Enrichment and visualization of small replication units from cultured mammalian cells.

DNA from cultured Chinese hamster cells has been fractionated to yield a population of DNA enriched for replicating molecules. Molecules containing replication structures were analyzed by electron microscopy, and replicon size was estimated. The enrichment procedure takes advantage of single-stranded regions characteristic of replicating molecules, and the greater affinity of mercuric ion for single-stranded rather than native DNA. After interaction with low concentrations of HgCl2, DNA with bound mercury is separated from the bulk of the DNA by virtue of its increased buoyant density in an isopycnic Cs2SO4 gradient. When DNA from cells labeled with [3H]thymidine for 45 s is interacted with HgCl2 and banded in Cs2SO4, the DNA with the highest specific activity is found in a dense region of the gradient. The high specific activity DNA behaves kinetically like nascent DNA since the radioactivity can be chased into main band if the cells are incubated for a further 2 h in excess unlabeled thymidine. Electron microscope analysis of the DNA in the enriched fraction confirmed that it contains a substantial fraction of molecules with replication structures. The level of enrichment is about 25-fold compared to unfractionated DNA or DNA taken from the main band of the Hg++/Cs2SO4 gradient. Of the replicating molecules visualized, 85% possessed a single replication structure. All molecules with multiple replication forms contained replicon sizes less than 5 micron, ranging from 0.2 to 4.5 micron. Replicon size was determined by measuring the distance from the center of one replication structure to the center of the adjacent replication structure on the same molecule. The replicons observed in this study are far smaller than can be detected by DNA fiber autoradiography and are in the same size range as the very small replication units reported in embryonic systems.


Analogous ultrastructure and surface properties during capping and phagocytosis in leukocytes.

Ultrastructural analyses have revealed striking similarities between Concanavalin A capping and phagocytosis in leukocytes. Both processes involve extensive membrane movement to form a protuberance or pseudopods; a dense network of microfilaments is recruited into both the protuberance and the pseudopods; microtubules are disassembled either generally (capping) or in the local region of the pseudopods (phagocytosis); and cells generally depleted of microtubules by colchicine show polarized phagocytosis via the microfilament-rich protuberance rather than uniform peripheral ingestion of particles via individual pseudopods. Cap formation can thus be viewed as occurring as an exaggeration of the same ultrastructural events that mediate phagocytosis. Similar changes in cell surface topography also accompany capping and phagocytosis. Thus, in nonfixed cells, Concanavalin A-receptor complexes aggregate into the region of the protuberance in colchicine-treated leukocytes (conventional capping) or into the region of pseudopod formation in phagocytizing leukocytes. In the latter case, the movement of lectin-receptor complexes occurs from membrane overlying peripheral microtubules into filament-rich pseudopods that exclude microtubules. These data provide evidence against a role for microtubules as "anchors" for lectin receptors. Rather, they indicate a preferential movement of cell surface Concanavalin A-receptor complexes towards areas of extensive (the protuberance) or localized (pseudopods) microfilament concentration. In conventional capping, Concanavalin A must be added to the colchicine-treated cells before fixation in order to demonstrate movement of receptors from a diffuse distribution into the protuberance. However, Convanavalin A receptors are enriched in the membrane associated with phagocytic particles as compared to the remaining membrane. This particle-induced redistribution of receptors is particularly prominent in colchicine-treated cells that phagocytize and are then fixed and Concanavalin A labeled; both lectin receptors and beads are concentrated over the protuberance. Thus, the final analogy between conventionally capped and phagocytic cells is that in both cases the properties of the plasma membrane in regions of microfilament concentration are modified by Concanavalin A itself (capping) or by the phagocytized particle, to limit locally the diffusion of Concanavalin A receptors.


A factor analysis of coping behaviors.

Undertook factor analysis on questionnaire data that deal with ways of diminishing tension. Data were obtained on 132 college students. Seven patterns of coping were identified tentatively: seeking social support, dysfunctional behavior, narcotizing anxiety, problem solving, reliance on professionals, bearing with discomfort, and escape.


Role of activation and sensory stimuli in recovery from lateral hypothalamic damage in the cat.

The early stages of recovery from lateral hypothalamic lesions were analyzed in 30 adult cats. In addition to aphagia and adipsia, neurological examination revealed deficits suggestive of deficient endogenous arousal, including somnolence, catalepsy, akinesia, and sensory neglect. Manipulations (tail pinch and injection of amphetamine) that counteracted these deficits also restored feeding. During recovery from aphagia, feeding gradually became activated by sensory stimuli (sight, feel, and smell) associated with food. These data suggest that activation is an important component in the control of normal feeding.


Polarized monolayers formed by epithelial cells on a permeable and translucent support.

An epithelial cell line (MDCK) was used to prepare monolayers which, in vitro, develop properties of transporting epithelia. Monolayers were formed by plating cells at high densities (10(6) cells/cm2) on collagen-coated nylon cloth disks to saturate the area available for attachment, thus avoiding the need for cell division. An electrical resistance developed within 4-6 h after plating and achieved a steady-state value of 104 +/- 1.8 omega-cm2 after 24 h. Mature monolayers were morphologically and functionally polarized. They contained junctional complexes composed of desmosomes and tight junctions with properties similar to those of "leaky" epithelia. Monolayers were capable of maintaining a spontaneous electrical potential sensitive to amiloride, produced a net water flux from the apical to basal side, and discriminated between Na+ and Cl- ions. The MDCK permeability barrier behaves as a "thin" membrane with negatively charged sites. It has: (a) a linear conductance/concentration relationship; (b) an asymmetric instantaneous current/voltage relationship; (c) a reduced ability to discriminate between Na+ and Cl- caused by lowering the pH; and (d) a characteristic pattern of ionic selectivity which suggests that the negatively charged sites are highly hydrates and of medium field strength. Measurements of Na+ permeability of electrical and tracer methods ruled out exchange diffusion as a mechanism for ion permeation and the lack of current saturation in the I/deltapsi curves does not support the involvement of carriers. The discrimination between Na+ and Cl- was severely but reversibly decreased at low pH, suggesting that Na+-specific channels which exclude Cl- contain acidic groups dissociated at neutral pH. Bound Ca++ ions are involved in maintaining the integrity of the junctions in MDCK monolayers as was shown by a reversible drop of resistance and opening of the junctions in Ca++-free medium containing EGTA. Several other epithelial cell lines are capable of developing a significant resistance under the conditions used to obtain MDCK monolayers.


Histology of benign virus induced tumors of the skin.

The majority of findings in relation to warts have been passed on from one textbook to the other since the end of the last century. More recent studies have been carried out with the electron microscope. But information is lacking as to histology, histochemistry, examination with the phase-contrast microscope, with the interference microscope, microradiography and other new techniques. Warts are a proliferation of the epidermis caused by a virus, and we know that the culprit acts in the epidermis itself. Warts are acanthomas, and a transition to malignancy is possible in predisposed persons. It is most remarkable that in the malignant tumors of epidermodysplasia verruciformis, no virus could be found. As the demonstration of viruses with the electron microscope and other techniques cannot be made as a matter of routine, we have to search for a simpler method with the light microscope. With the application of more elaborate procedures, new information about epidermal proliferation will certainly be obtained.


Ultrastructural resemblance of basal cell epithelioma to primary epithelial germ.

Six examples of basal cell epithelium were compared to fetal and adult skin. Five parameters were used in this study: abnormally large aggregates of melanosomes in epithelial cells; the paucity of half-desmosomes; the increase of microfilaments in the cell periphery; clustered membrane-limited granules; and desmosome-like structures of stromal fibroblasts. All of these indicators were positive in both basal cell epithelioma and fetal hair follicle; but they were negative in both fetal and adult epidermis. Therefore, it was concluded that basal cell epithelioma seems to mimic fetal primary epithelial germ. Interestingly, stromal fibroblasts of basal cell epithelioma phagocytize collagen fibers, and membrane-limited granules were found both inside and outside the tumor cells facing the digested collagen stroma. In view of the collagenolytic activity of the homogenate of basal cell epithelioma, membrane-limited granules might represent zymogen granules for collagenases.


Nutrient quality and acceptability of mechanically deboned meat.

The meat processing industry has great incentive to push for the lifting of the ban on MDM. By using MDM equipment, much meat now being lost could be salvaged for human consumption with great economies and world food shortage implications. The properties of mechanically deboned meat vary with the percentage of bone and marrow in the original products, the equipment, and by other factors. The question of future use of MDM hinges on its readmission to the market, based on safety and health aspects. Dietiticians and others in health care service may be asked to give an opinion concerning the use of MDM. Consideration of the possible addition of nutrients over and above those usually supplied in meats may be a positive factor. Certainly, if its use is reinstated, health care professionals will need to be aware of the implications of including such products in the foods chosen for themselves and their patients.


Effect of diet on fecal nutrients.

Calculated and chemically analyzed nutrient values for three weighed constant diets were dissimilar for calcium, magnesium, protein, and fat, and similar for fiber and ash. Fecal nutrient concentrations of ten healthy men fed the same constant diets were quite variable. Feeding constant weighed diets of similar composition does not assure the same fecal residue in the large colon of human subjects.


Binding of IgG and papain-derived fragments to Fc receptors of the fetal rabbit yolk sac membrane.

Quantitative measurements of the in vitro binding of 125I-labeled rabbit IgG (IgGR), and its Fab-1, Fab-2, and Fc fragments to receptors on the fetal rabbit yolk sac membrane (YSM) were carried out by incubating equimolar solutions (1 X 10(-5) M) of IgGR and of each of its fragments with formalin-fixed discs (3.5 cm2) of the YSM. It was found that 97, 4, 2, and 96 pmoles of IgGR, Fab-1, Fab-2, and Fc, respectively, were bound per YSM disc. Since the binding characteristics of intact IgGR were fully conserved in the Fc piece, the results establish that the YSM receptor for IgG is an Fc receptor. It was also shown that whereas IgGR retained its binding ability after exposure to stress (55 degrees C, 10 min), free Fc did not. These findings, together with knowledge of the IgG structure, imply that the YSM receptor recognition unit of IgGR resides in the CH2 domain of its Fc piece.


Activation of the classical and alternative pathways of complement fixation by immune complexes containing normal and tryptophan-modified immunoglobulin G.

Koshland's reagent (2-hydroxy-5-nitrobenzyl bromide (NBB)) has been shown to modify tryptophanyl residues in anti-ovalbumin IgG. As little as 2 moles NBB/mole IgG antibody are sufficient to block the classical pathway of complement activation when the antibody is complexed to antigen (ovalbumin). In contrast, immune complexes containing antibody with the same degree of tryptophanyl substitution will activate the alternative pathway of complement fixation. Immune complexes containing F(ab')2 fragments derived from anti-ovalbumin IgG do not activate the classical pathway. When measuring the percentage activation of C3 using the method of Laurell, NBB does not affect the alternative pathway of the complement system up to a molar ratio of 2 NBB/F(ab')2. The above findings, provide a means to evaluate the relative contribution of complement activation by the different pathways.


Plasma concentrations of calcium, chromium, copper, iron, magnesium, and zinc in maternal and cord blood and their relationship to low birth weight.

A study of the relationship between low birth weight and concentrations of six metals in maternal and cord plasma was conducted. Maternal and cord blood were collected at delivery. Cases and controls were matched for maternal age (+/- 3 yr), race, parity, socioeconomic status, and smoking habits and the sex of the neonate. Plasma concentrations of calcium, copper, magnesium, and zinc were determined by flame atomic absorption spectrophotometry; plasma chromium and iron concentrations were determined by flameless atomic absorption techniques. Mean maternal plasma concentrations were significantly lower in the low-birth-weight group than in the controls for iron (p = 0.012) and calcium (p = 0.007). Mean cord plasma concentrations were also significantly lower for calcium (p = 0.037). There were no statistically significant differences between the low- and normal-birth-weight groups for the maternal or cord chromium, copper, magnesium, and zinc concentrations or for the cord iron concentrations. It is probably true that many factors, acting additively or synergistically, can produce low birth weight, and that low birth weight acts only as a marker for a number of biologic insults. The results of this study suggest that nutrient metals may be one of these factors.


Differences in the release of melanocyte-stimulating hormone in vitro by rat pituitary glands collected at various times during the oestrous cycle.

The release of melanocyte-stimulating hormone (MSH) into the medium during incubation and the pituitary tissue content of MSH were measured separately using pituitary glands collected from rats at various stages of the oestrous cycle. The MSH was measured by a biological assay using a synthetic alpha-MSH as standard. The release of MSH was maximal during thepro-oestrous phase and MSH content of the pituitary gland was highest during dioestrus. The influences of the tripeptide Pro-Leu-Gly-NH2, which inhibits MSH secretion in vivo, and of progesterone on the release of MSH in vitro were studied with tissue collected at various phases of the oestrous cycle. Pro-Leu-Gly-NH2 was effective in inhibiting MSH release both at pro-oestrus and oestrus but not at dioestrus. Progesterone overcame this inhibition.


Interaction of beta1H globulin with cell-bound C3b: quantitative analysis of binding and influence of alternative pathway components on binding.

Purified beta1H globulin (beta1H) was shown to bind to C3b coated cells by both immunofluorescent and radioactive tracer techniques. With EAC43, the amount of beta1H bound was directly proportional to the amount of C3 used to prepare the cells; EA, EAC14 and EAC14oxy2 bound very small amounts of beta1H. The C3b binding site on beta1H was labile in that not all of the purified 125I-beta1H was capable of binding to C3b, even when an excess of cell-bound C3b was present. Scatchard analysis of binding of beta1H to C3b-coated cells indicated an equilibrium constant of 10(9) L/M. Deviations from linearity were regularly found on Scatchard analyses. This was consistent with the hypothesis that the beta1H binding sites exhibit negative cooperativity in that as more sites become occupied, it becomes more difficult to fill the remaining sites. The stoichiometry of the reaction between C3b and beta1H was examined using EAC14oxy23 prepared with 131I-C3 and beta1H labeled with 125I. Between 0.5--0.8 beta1H molecules were bound per C3b molecule. Other alternative pathway components influenced the binding of 125I-beta1H to cell bound C3b. Both C3b and native C3 inhibited binding of labeled beta1H at an efficiency approximately 1/1,000 that of unlabeled beta1H. Factor B inhibited binding with 1/280 the efficiency of unlabeled beta1H. Properdin caused a dose-dependent increase in the binding of beta1H; this enhancement was abrogated if B was also present in the reaction mixture. Scatchard analysis indicated that the enhancement of beta1H binding by P resulted in an increased number of available binding sites rather than an increase in the affinity of binding.


Affinity of fibronectin to collagens of different genetic types and to fibrinogen.

Fibronectin, a fibroblast surface protein, was purified from human and chicken plasma and extracts of cultured chicken fibroblasts with affinity chromatography on gelatin coupled to Sepharose particles. A fibronectin-like protein was also isolated from the plasma of Torpedo fish. The collagen binding properties of fibronectin were studied with several genetically distinct collagens. Heat denatured types I, II, and III collagens were equal in their binding capacity and more active than the native collagens or A and B chains. Native type III collagen was more active than the other native collagens. Human and chicken fibronectins showed approximately the same pattern of specificity. Identical specificities were shown by the plasma and fibroblast forms of chicken fibronectin. Two cyanogen bromide peptides of the collagen alpha1 (II) chain, CB8 and CB12, derived from different parts of the chain, were active in fibronectin binding. A polymer of the tripeptide pro-gly-pro, and polyproline were inactive. Fibronectin also binds to fibrinogen and fibrin. Comparison of this binding to collagen binding showed that fibrinogen inhibited binding of fibronectin to collagen, but was less active than native collagen. Two other fibrous proteins, tropoelastin and keratin, did not bind fibronectin. The binding of fibronectin to fibrinogen was inhibited by collagen and incorporation of fibronectin into blood clot in the cold was inhibited by gelatin. These results suggest that the binding of fibronectin to collagen and fibrinogen depends on the same binding site in the fibronectin molecule. It is proposed that cell surface fibronectin mediates attachment of cells to the collagenous extracellular matrix and to a temporary fibrin matrix in a wound.


Synthesis and secretion of plasma proteins by embryonic chick hepatocytes: changing patterns during the first three days of culture.

A simple model system is described for studying synthesis of plasma proteins. The system is based on chick embryo hepatocytes in primary monolayer culture which synthesize a broad spectrum of plasma proteins and secrete them into the culture medium. The secreted proteins are stable and consist almost exclusively of plasma proteins. The cultured cells are nonproliferating hepatic parenchymal cells whose cell mass remains constant in culture. By a modification of Laurell's rocket immunoelectrophoresis, the secreted plasma proteins can be detected in nanogram amounts in 3 microliter of unconcentrated culture medium. Kinetics of secretion are obtained by sequential assay of proteins accumulating in the medium. In this system it is demonstrated that: (a) intracellular plasma protein levels are equivalent to less than 5% of the daily secretion; (b) synthesis and secretion are continuous; and (c) the overall half-time for plasma protein movement along the secretory pathway is less than 10 min. From these results, it follows that the rate at which the plasma proteins are secreted gives a valid estimate of their rate of synthesis. This feature of the culture and the sensitivity of the assay allow routine measurements of plasma protein synthesis without disruption of the cells and without the use of radioisotopes. It is shown, furthermore, that the overall rate of plasma protein synthesis in cultured hepatocytes is constant over a 3-day period and is similar to that of the intact liver. 3,000,000 cells, containing 1 mg cell protein, synthesize 0.2 mg of plasma proteins daily, amounting to one-fifth of hepatocellular protein synthesis. Under the conditions used, albumin synthesis steadily decreases with culture time whereas the synthesis of many other plasma proteins increases. The observed phenotypic changes and reorganization of plasma protein synthesis illustrate how the system may be exploited for studying the regulatory processes governing plasma protein synthesis.


Quantitative determination of the binding capacity of the sex hormone-binding globulin, using agar gel electrophoresis.

An easy, rapid and precise technique for the determination of the binding capacity of the sex hormonebinding globulin (SHBG) is described. The plasma is incubated with [3H]5 alpha-dihydrotestosterone (DHT) either alone, or together with an excess of unlabelled DHT. The SHBG-binding peaks are demonstrated by agar gel electrophoresis according to Wagner (1972) Hoppe-Seylers Z. Physiol. Chem. 353, 1235--1245), and the SHBG-binding capacity is calculated from the radioactivity specifically bound to the SHBG peak, corrected for the dissociation of the [3H]DHT from SHBG during the 90 minute electrophoresis. In addition to investigating various problems of methodology, the following clinical results were obtained: 1 Normal range (x +/- s) of the SHBG-binding capacity for males (age 22--41; n = 26) 38 +/- 11 nmol/1.2. An older male group has, with 48 +/- 10 nmol/l, a a significantly higher binding capacity. 3. The highest values found so far were in pregnancy plasma of the third trimenon (330 and 400 nmol/l).


Central and peripheral catecholamines and phenylethanolamine-N-methyl-transferase activity during the oestrus cycle.

Natural variations in monoamine levels in the adrenal gland, whole brain, hypothalamus and plasma during the oestrus cycle were determined in Sherman rats. Noradrenaline content of adrenal gland was at its highest level during met-oestrus phase while adrenaline was at its lowest level. During pro-oestrus adrenaline in the adrenal gland was at the maximum value. Plasma adrenaline did not change significantly during the oestrus cycle. However plasma noradrenaline was significantly higher during metoesrus compared to the value of di-oestrus and pro-oestrus. In the hypothalamus noradrenaline level was at its highest value during di-oestrus and at its lowest during met-oestrus, while brian noradrenaline reached its maximum value during pro-oestrus. The sum of plasma adrenaline and noradrenaline showed maximum level during met-oestrus phase but at the same time total adrenal adrenaline plus noradrenaline was lowered. The variations in adrenaline and noradrenaline in the adrenal gland did not correspond to the changes in the activity of enzyme, phenylethanolamine-N-methyltransferase (PNMT). The activity of PNMT reached its maximum value during met-oestrus phase of the oestrus cycle. The observed variations in adrenal, brain, hypothalamus and plasma catecholamines can be attributed to the modification in endocrine activity which takes place during the oestrus cycle.


Activity of catechol-o-methyltransferase in brain regions and adrenal gland during the oestrus cycle.

The activity of the enzyme catechol-O-methyltransferase (COMT) during four different phases of the oestrus cycle were determined. Brain and hypothalamus had highest level of COMT activity during oestrus phase, while at pro-oestrus it was at its lowest level. COMT activity in the adrenal gland was also modified during the four phases with the maximum level at met-oestrus and minimum at pro-oestrus phase. The results provide evidence to show that COMT in the brain, hypothalamus and the adrenals is markedly affected by changes in physiological status of the female rats and its evolution in brain is different from adrenal gland during the oestrus cycle. The variations in the activity of COMT may be the consequence of modified endocrine activity which takes place naturally during oestrus cycle.


The effect of dietary selenium and vitamin A on biochemical parameters and survival of young among white-tailed deer (Odocoileus virginianus).

Thirty-two adult female white-tailed deer were assigned to four complete pelleted diets (+/- 45 ppm vitamin E; +/- 0.2 ppm selenium). Selenium and vitamin E concentration in the unsupplemented diet was 0.04 and 5.5 ppm, respectively. Biochemical parameters of the erythrocyte (RBC) glutathione peroxidase system and survival of off-spring to weaning were followed for 2 years. At the end of the second year, 12 male young (3 per treatment) and the remaining adults were killed, and liver and muscle parameters of the glutathione system determined. Plasma selenium (Se) and vitamin E (E) were significantly lower among unsupplemented adults within 6 months of treatment and remained essentially constant from 10 months on. In vitro hemolysis and mortality of young were affected by dietary E but not by Se. Tissue glutathione peroxidase (GSH-Px) was correlated with tissue Se in all tissues measured (RBC, liver and muscle). Tissue Se, in turn, was related to dietary Se. Thus, dietary Se deficiency (Se = 0.04 ppm) resulted in biochemical deficiency (depressed GSH-Px). This was not reflected in gross lesions among the adults, nor in increased mortality among young.


The life cycle of Eimeria falciformis var. pragensis (Sporozoa: Coccidia) in the mouse, Mus musculus.

The life cycle of Eimeria falciformis var. pragensis, established from a single oocyst, is described in experimentally infected mice (Mus musculus). The coccidium had a prepatent period of 7 days and a patent period of 10--16 days. Oocysts were spherical to ellipsoidal in shape and measured 21.2 x 18.3 micron. Sporulation time was 3 to 3.5 days. Sporocysts measured 12.2 x 7.2 micron and contained a circular to avoid granular sporocyst residuum measuring 5.5 X 5.0 micron. One, 2 or 3 circular to rectangular polar granules were observed within each sporulated oocyst. The endogenous stages developed primarily in the cecum and colon and only occasionally in the lower ileum. Four generations of schizonts were found. Mature 1st-generation schizonts, first observed 48 hr postinfection (PI), measured 17.8 x 12.3 micron and had 12 merozoites that measured 13.3 x 2.0 micron. Mature 2nd-generation schizonts appeared 78 hr PI. They measured 10.2 x 9.3 micron and had 8 merozoites measuring 5.0 x 1.6 micron. Mature 3rd-generation schizonts appeared first at 114 hr PI and measured 17.5 x 10.2 micron and had 10 merozoites that measured 12.4 x 1.8 micron. Mature 4th-generation schizonts appeared first at 144 hr PI. They measured 18.2 x 15.3 micron and had 18 merozoites. The merozoites of the 4th-generation schizont were 4.5 x 1.2 micron. Mature macrogamonts and microgamonts developed simultaneously appearing at 156 hr PI. Macrogamonts measured 16 x 14.5 micron and microgamonts were 18.2 x 15.3 micron. In experimentally infected rats (Rattus norvegicus), development of E. falciformis var. pragensis progressed only as far as mature 1st-generation schizonts.


Use of hamster antisera in the preliminary differentiation of Leptospira interrogans servars hardjo and balcanica.

Preliminary differentiation of Leptospira interrogans serovars hardjo and balcanica can be made with antisera that are collected from hamsters after experimental infection with serovar hardjo and selected for high homologous and low or nil heterologous titres, as measured by the microscopic agglutination test. Rabbit antisera against serovars hardjo and balcanica, cattle antisera against hardjo and sheep antisera against the serogroup Hebdomadis each agglutinated hardjo and balcanica to a similar titre.


Cellular and molecular toxicology of lead. I. Effect of lead on cultured cell proliferation.

Growth studies were done on a cultured rat liver cell line (RLC-GAI) grown in a chemically defined medium in the presence of lead nitrate. Lead reversibly inhibited the growth of these cells even after 6 d of exposure to the heavy metal. To compare lead sensitivity in various cell lines, GI50 and LD50 values were determined in the RLC-GAI cells as well as two glioma cell lines (B82 and C(6)) and a neuroblastoma cell line (N18). The LD50 values paralleled but were consistently lower than the GI50 values. Since lead is known to affect heme synthesis, hemin was added to test the possibilty of preventing the growth-inhibitory effect of the lead. The growth capacity of lead-treated cells did not change with the addition of hemin. It is thought that differentiated cultured cell lines such as these could be useful in examining the molecular mechanism of lead toxicity.


Cellular and molecular toxicology of lead. III Effect of lead on heme synthesis.

The effect of lead nitrate on the biosynthesis of heme and the cellular uptake of (59)Fe was studied in an established rat liver cell line (RLC-GAI) grown in serum-free medium. Heme synthesis was shown to be increased in lead-treated cells when determined by measuring the amount of (59)Fe incorporated into the heme fraction of cell homogenates; concomitant with increased (59)Fe incorporation into heme, cellular uptake of (59)Fe was also increased. By contrast, heme synthesis was inhibited by lead in a dose-dependent manner when determined by measuring the conversion of ((14)C) aminolevulinic acid into heme under identical experimental conditions. Cellular degradation of heme was not found to be significantly affected by lead. It is proposed that lead inhibited the biosynthesis of heme and that the increased incorporation of (59)Fe into the heme fraction of the lead-treated cells was the result of the increased uptake of (59)Fe and hence labeling of the heme molecules. Evidence is presented that suggests that only (59)Fe present in solution as a low-molecular-weight complex was accumulated in increased amounts by lead-treated cells.


Angiosarcoma of the liver associated with diethylstilbestrol.

Angiosarcoma of the liver occurred in a 76-year-old man who had been treated for a well-differentiated adenocarcinoma of the liver with diethylstilbestrol for 13 years. Angiosarcoma was also present within pulmonary and renal arteries. The possibility that the intraarterial lesions might represent independent primary tumors is considered.


[Genetic and physiological mechanisms of the hypertensive reaction in emotional stress in rats].

The experiments were performed on rats of three inbred strains (Wistar, August, and Spreg-Dowley). Arterial pressure was measured during acute emotional stress. The reactivity of arteries to vasopressor stimuli, the corticosteroid function, and the humoral pressor activity of plasma were also studied to investigate some physiologic mechanisms of genetically determined differences in the level of arterial pressure during stress. It was established that the rat strains which were examined did not differ in the level of arterial pressure at rest, but showed marked differences in pressure under conditions of stress: the greatest rise in pressure was noted among August rats, the least among Wistar rats, while animals of the Spreg-Dowley strain occupied an intermediate position. It is concluded that inter-strain differences in the pressor reaction reflect genetical peculiarities in the system of nonspecific stress reactivity of animals.


Anthelmintic control of concurrent Hymenolepis nana and Syphacia obvelata infections in the mouse with uredofos.

Tests were made to determine the efficacy of uredofos in either the diet or drinking water for controlling induced Hymenolepis nana and naturally acquired Syphacia obvelata infections in the mouse. Four levels of administration (50, 75, 100, and 125 parts per million) were used in a 6-day drugdiet assay. Consistent removal of Hymenolepis nana occurred only at 125 parts per million, whereas removal Syphacia obvelata was complete at all levels. The disodium salt of uredofos was given in the drinking water. Three levels of administration (12, 18 and 25 mg/kg) were used, and the treatment period was limited to 24 hours. Complete removal of Hymenolepis nana occurred at 25 mg/kg and Syphacia obvelata was completely eliminated at all levels.


Mechanical failure (leaflet disruption) of a porcine aortic heterograft: rare cause of acute aortic insufficiency.

Use of the Hancock, glutaraldehyde-preserved, stented heterograft for aortic valve replacement has gained wide acceptance in the past 7 years. Nevertheless, very little is known about the long-term mechanical and pathological characteristics following implantation. A rare case is presented in which mechanical valve failure occurred secondary to leaflet disruption in the absence of infection 23 months after implantation. The literature is reviewed and the implications of this unusual complication are discussed.


Hemolytic anemia associated with heterograft replacement of the mitral valve.

The first case of overt hemolytic anemia following mitral valve replacement with a porcine heterograft is reported. Cardiac catheterization failed to reveal a paravalvular leak or valvular incompetence to account for the hemolysis. Red cell traumatization by the Dacron-covered Stellite ring and stent is suggested as the cause of hemolysis with the porcine heterograft.


Primary thrombocythemia in the young patient.

Primary thrombocythemia is typically a disease of older patients and frequently is associated with thrombosis and hemorrhage. Seven female and two male patients younger than 30 years were evaluated because of platelet counts exceeding 1 million/mm3. No hemorrhagic or thrombotic problems existed before diagnosis or developed during the follow-up period of 14 months to 10 years. Platelet function studies done in six of the nine patients showed absent aggregation with epinephrine and variable aggregation with adenosine diphosphate, as are seen in other chronic myeloproliferative states. One patient had spontaneous aggregation. Secondary causes of thrombocytosis were excluded. Only one patient received specific chemotherapy, which was given before 1973. Thus, thrombocythemia without a secondary cause appears to be much more benign in the young patient than in the older, and aggressive chemotherapy to lower the platelet count is not necessarily justified unless serious complications develop.


The sublabial transseptal transsphenoidal approach to the hypophysis.

A simple and safe technique for the sublabial transseptal transsphenoidal approach to the hypophysis and parasellar region is described. A review of the literature reveals that this technique and other transsphenoidal routes to the hypophysis were performed more than half a century ago.These procedures fell into disfavor because fo low magnification and insufficient illumination of the operative field, infection and inadequate postoperative endocrine replacement therapy. With today's antibiotic therapy and hormonal replacement, plus the use of the operating microscope, the transsphenoidal route to the hypophysis has gained renewed interest among neurosurgeons and otolaryngologists. Each of the transsphenoidal routes and the advantages of the "from below" approach are described. The applications of transsphenoidal approach and the nonsurgical modalities for hypophysectomy are reviewed. The simplicity and safety of the sublabial transseptal transsphenoidal approach depend on a thorough familiarity with the surgical anatomy, proper positioning of the patient, and the availability of appropriate instrumentation. Photographs of specially prepared whole head anatomical specimens plus skull dissections with radiographic correlation illustrate the pertinent anatomy. Some of the vital structures to be identified and avoided are the optic canals, carotid arteries, circular sinuses, cavernous sinuses, III, IV, V, VI cranial nerves, foramen rotundum, medial walls of the orbits, medial walls of maxillary sinuses, medial pterygoid plates and pterygoid canals. A method for preoperative determination of key distances within the patient's skull is described along with other preoperative tests. This paper discusses the self-retaining speculum and other new instruments for this procedure. A gauge mounted on the front end of the speculum is calibrated to measure the size of the opening at the tip of the speculum. Thirty cases are included in this report, six of which are presented in detail. No operative mortality, CSF rhinorrhea, visual damage carotid or cavernous sinus hemorrhage fracture of the medial pterygoid plates or maxilla were encountered in this series. Three patients developed diabetes insipidus and two patients had meningitis which responded to antibiotic therapy.


[Radioprotective effect of acute hypoxia on 5-day-old mice preliminarily adapted to oxygen deficiency].

Studies of 5-day mice F1 (CBA X C57Bl) demonstrated that an exposure of animals to acute hypoxia (5% O2--95% N2) during their irradiation produced a different effect on the spleen and the growing cerebellar cortex. In these circumstances lesions of well oxygenated spleen tissues were noticeably reduced, whereas cerebellar cortex cells characterized by a low oxygen tension and a high tolerance to anoxia remained essentially unprotected. The findings are discussed in the light of adaptation concepts postulating that oxygen tension in cells is regulated, depending on the level of its uptake which in turn is determined by the relative oxygen content in the surrounding medium.


[Immunologic and physico-chemical properties of hyperimmune antibodies with different affinities].

By immune chromatography fractions with various reaction rates of antigen precipitation and neutralization of toxin "in vivo" have been isolated from a common pool of antibodies. Antibodies of higher pI possessed an elevated relation of basis amino acid residues to unsubstituted dicarboxylic residues as well as greater affinity. The data suggest an important role of ion interaction and a general scheme of antigen and antibody molecules structure for immune reactions.


Diurnal variations in the motor activity of the rat: effects of inhibitors of the catecholamine synthesis.

The effects of the inhibitor of the tyrosine-hydroxylase H 44/68 and the inhibitor of the dopamine-beta-hydroxylase FLA 63 on the diurnal variations of the motor activity was studied in male Wistar rats, which were kept under standardized conditions of light and darkness (L:D = 12:12 h). The motor activity was continuously registered in groups of 5 rats using a two-channel Animex motimeter. During light FLA 63 (40 mg/kg, s.c.) greatly increased motor activity on acute application and during darkness the physiological elevation in motor activity was further but slightly increased. H 44/68 (200 mg/kg, i.p.) also increased motor activity during light, but in contrast to FLA 63 greatly reduced motor activity during darkness. The results indicate that though dopamine and noradrenaline are involved in the regulation of behavioural components, one or the other catecholamine may play a predominant role at different times of the day. Thus, it seems worthwhile to study the effects of drugs separately during light and during darkness.


Diurnal rhythm in the central dopamine turnover in the rat.

Under controlled conditions of environmental light and darkness of 12:12 h the turnover of dopamine and noradrenaline in brain of male Wistar rats was studied at different times of the day. The turnover was calculated from the decline of the amine concentrations either after inhibition of the tyrosine-hydroxylase with H 44/68 (200 mg/kg, i.p.) or after inhibition of the dopamine-beta-hydroxylase with FLA 63 (40 mg/kg s.c.). Whereas the noradrenaline turnover showed only slight but not significant variations within 24 h, the turnover of the central dopamine exhibited significant variations with increased turnover rates in the second half of the light and first half of the dark period. Thus, diurnal variations have to be taken into account when studying the effects of drugs on the turnover of biogenic amines in the central nervous system.


Subsensitivity of striatal and mesolimbic dopamine target cells after repeated treatment with apomorphine dipivaloyl ester.

The effects of acute and repeated treatments with the dipivaloyl ester of apomorphine on behaviour and brain dopamine metabolism were compared in rats. A single injection of the ester (50 mg/kg i.p.) indued a stereotyped behaviour lasting for at least 6 h and a concomitant decrease in striatal HVA levels. After repeated treatment (twice daily for 7 days) with the drug, both the stereotyped behaviour and the decreases in striatal HVA levels were attenuated as compared to acute treatment; the minimal dose tested which induced this tolerance was found to be 25 mg/kg i.p. The minimal length of treatment with 50 mg/kg of the ester after which tolerance was observed was 3-4 days. The ED50 for haloperidol-induced catalepsy was about 4 times lower in rats treated with apomorphine dipivaloyl ester (50 mg/kg) for 7 days than in naive rats. Similarly, a shift to the left of the haloperidol dose-response curve for the increase in striatal dopamine metabolite levels was observed in rats treated subacutely with the ester as compared to control rats. Repeated treatment (7 days) with the dipivaloyl ester of apomorphine also attenuated the decrease in NVA levels seen with acute treatment in nucleus accumbens and tuberculum olfactorium; however, the threshold dose inducing tolerance in limbic regions was higher than in striatum. No difference in the brain concentrations of apomorphine was found after acute and repeated treatments with the ester. Thus, the present study provides evidence for the development of subsensitivity of dopamine receptors after repeated administration of aopomorphine dipivaloyl ester.


[Hemangioblastoma of the cauda equina--a case report (author's transl)].

We reported the case of a 40-year-old man who was hospitalized to our department on November 16, 1975 with a year history of neuralgia in the saddle region and vesicorectal dysfunction. Examination of CSF on lumbar puncture at L4-5 revealed xanthochromia with a protein content of 2,560 mg/dl. Myelography revealed a tortuous filling defect at the level of L2 coupled with complete blockade at L3 level. Selective spinal angiography of the left 12th intercostal artery demonstrated the enlarged Adamkiewicz's artery. This blood vessel was found to enter a diffuse uniform density, where no distinct blood vessels were visible. Within one second after the injection of contrast agent an efferent vein appeared from the right side of the density, ascended to the level of Th12 and then, upon turning, descended to the pelvic canal. These findings suggested a hemangioblastoma of the spinal cord. Laminectomy was performed at levels of L2 through L4 and a hemangioblastoma of the cauda equina was totally excised at L3 level. Although the postoperative course was complicated by a transient dysuria and hypesthesia at S1-S5 levels, complete cure was achieved in a month. In the present paper clinical features and neuroradiological examination of a hemangioblastoma of the spinal cord were described.


Effects of hypothalamic deafferentation on ovulation and estrous cyclicity in the female guinea pig.

The effects of hypothalamic deafferentiation on the estrous cycle and ovulation were studied in the mature female guinea pig, a spontaneous ovulator with a true luteal phase. Animals were stereotaxically deafferentated using the Haláxz knife technique. (1) Large complete deafferentation of the medial basal hypothalamus (MBH; arcuate nucleus, median eminence (ME), and a ventral part of the ventromedial nucleus) did not block cyclic ovulation, although the cycle became slightly prolonged. (2) Small complete deafferentation which excluded the ventromedial nucleus from the MBH and partially damaged the arcuate nucleus in anovulation and constant closure of the vaginal membrane. (3) Large anterior deafferentation, which eliminated neural afferent from medial preoptic area (MPO), suprachiasmatic portion of the preoptic nucleus (POSC) and the anterior periventricular area to the MBH, was effective in blocking ovulation and inducing constant vaginal opening. In most of the cases, the knife passed rostral to the suprachiasmatic nucleus (SCN). (4) Small anterior deafferentation at the caudal border of the optic chiasma did not block ovulation if the arcuate nucleus and ME were intact, although the cycle sometimes became irregular. (5) Posterior deafferentation at the level of the mammillary bodies failed to interfere with cyclic ovulation. It is concluded that, in the guinea pig, the deafferentated MBH is capable of sustaining both tonic and phasic secretion of gonadotropins (Gns) necessary for maintenance of normal estrous cycles and ovulation. However, this function of the MBH may also be modulated by facilitatory and inhibitory influences arising from extrahypothalamic areas.


[Sea urchin sperm DNP. I. Chemical composition and template properties of DNP].

Electrophoretic mobility, amino acid composition and salt dissociation of histones isolated from sperm of sea urchin Strongylocentrotus intermedius and calf thymus cells were studied. The special arginine-rich histone fraction (I) has been observed in sea urchin sperm chromatin, this fraction being absent in calf thymus chromatin. Dissociation of lysine-containing histone fractions from sea urchin chromatin occured in the range of 0.7 to 1.0 M NaCl concentrations. H1 of calf thymus chromatin was totally extracted with 0.6 M NaCl. In the course of a further increase of salt concentrations (up to 1.5 M NaCl) a practically total extraction of histones from sperm chromatin was observed, while about 20% of proteins remained bound to DNA in thymus chromatin after extraction with 2.0 M NaCl. The template activity of non-extracted DNP preparations from urchin sperm was equal to 2-3% of that of totally deproteinized DNA. The template activity of DNP gradually increased at protein extraction from DNP preparations. The hybridization capacity of RNA transcribed on partially dehistonized DNP templates in vitro also increased.


Luteinizing hormone secretion in hemidecorticate female rats under several experimental conditions.

Luteinizing hormone (LH) secretion by the anterior pituitary gland was investigated in hemidecorticate (HD) rats under several conditions. Higher plasma and lower pituitary LH levels were observed in HD rats in the afternoon of proestrus, after unilateral ovariectomy, and at the 7th and 14th days after bilateral castration. The ovarian hypertrophy observed in HD rats did not differ from control. When hormonal substitutive therapy was started 3 days after bilateral ovariectomy, larger doses of estradiol benzoate (EB) were required to reduce plasma LH levels in control than in HD animals. The increase in pituitary weight was, however, significantly higher in the HD castrated group. When substitutive therapy started at the 7th and 14th days after castration no significant differences between the 2 experimental groups were observed. The results of substitutive therapy suggest that hemidecortication induces an increase in the sensitivity of hypothalamic-pituitary axis to estrogen negative feedback. This change in sensitivity is clearly seen in HD rats during the first few days after castration. These results suggest that hemidecortication may release the hypothalamus from inhibitory influences coming from rhinencephalic or cortical structures, thus rendering the preoptic-suprachiasmatic complex (POA-SCH) more sensitive to LH-releasing mechanisms.


Transient ischemic attacks: a prospective study of 225 patients.

Between the years 1964 and 1973, 225 patients with transient ischemic attacks (TIAs) due primarily to atherosclerosis were evaluated and treated. They have now been followed for from 3 to 14 years (average 5.5 years). As of 1976, 82 of the 225 patients were dead, 21 from cerebral infarction, 52 from heart disease and nine from other causes. Of the 56 untreated patients, 11 (19 percent) had cerebral infarctions, four (7 percent) of which were fatal; six (11 percent) were still having TIAs. Of the 45 patients medically treated, 10 (24 percent) had cerebral infarctions, three (7 percent) of which were fatal; 11(25 percent) still experienced TIAs. In the surgical group of 124, 27 (21 percent) had postoperative cerebral infarctions, seven (6 percent) of which were fatal; 23 (18 percent) had cerebral infarctions during follow-up, of which seven (6 percent) were fatal; and 15 (12 percent) were still having TIAs. No statistically significant differences (p less than 0.05) related to cerebral infarction or TIAs developed among the three groups. The majority (23 percent) eventually succumbed to myocardial infarction, leading us to conclude that great emphasis must be placed upon TIAs as a warning for cardiac as well as cerebrovascular disease.


The Harvard Cooperative Stroke Registry: a prospective registry.

Data from 694 patients hospitalized with stroke were entered in a prospective, computer-based registry. Three hundred and sixty-four patients (53 percent) were diagnosed as having thrombosis, 215 (31 percent)as having cerebral embolism 70 (10 percent) as having intracerebral hematoma, and 45 (6 percent) as having subarachnoid hemorrhage from aneurysm or arteriovenous malformations. The 364 patients diagnosed as having thrombosis were divided into 233 (34 percent of all 694 patients) whose thrombosis was thought to involve a large artery and 131 (19 percent) with lacunar infarction. Many of the findings in this study were comparable to those in previous registries based on postmortem data. New observations include the high incidence of lacunes and cerebral emboli, the absence of an identifiable cardiac origin in 37 percent of all emboli, a nonsudden onset in 21 percent of emboli, and the occurrence of vomiting at onset in 51 percent and the absence of headache at onset in 67 percent of hematomas.


Cerebrovascular disease in infants and children: a study of incidence, clinical features, and survival.

A 10-year review of the Mayo Clinic experience with childhood cerebrovascular disease unrelated to birth, intracranial infection, or trauma identified 69 patients (38 with ischemic stroke, and 31 with subarachnoid or intracerebral hemorrhage). Although children with cerebral infarction had better survival, they experienced more residual disability than children with cerebral hemorrhage. The medical records-linkage system for Rochester, Minnesota residents made it possible for the first time to study cerebrovascular disease in a well-defined childhood population. Records from all medical facilities serving this population (average of 15,834 resident children) showed four strokes over 10 years (average annual incidence rate of 2.52 cases per 100,000 per year).


Delayed cerebral ischemic episodes distal to occlusion of major cerebral arteries.

Some time after deletion of occlusion of the appropriate artery, 20 patients had transient ischemic attacks and seven had strokes. The common statement that transient ischemic attacks cease when an artery becomes occluded must, therefore, be modified. Seventeen of the 20 patients reported here developed symptoms weeks to years after the appropriate artery was known to be occluded, while 10 attacks occurred within 1 week after occlusion. Embolism through collateral circulation probably accounts for the delayed ischemic events in most of the patients, and hemodynamic factors in a few. The stump of the occluded artery may be the site of atheromatous ulceration. The possibility of revascularization procedures for patients with occluded arteries makes pertinent these observations about potential embolic sources.


Radionuclide angiography: a sensitive diagnostic test for anterior circulation ischemia.

Radionuclide angiography, using high resolution equipment, is a sensitive noninvasive, safe, and rapid diagnostic test for ischemia of the anterior circulation of the brain. The test permits recognition of focally increased or decreased circulation immediately following the onset of a neurologic deficit. The sensitivity of the test is improved by using multiple projections of the head. The distribution of the anterior cerebral artery is best seen in the anterior projection; the lateral projection is used to resolve the superior and inferior divisions of the middle cerebral artery or to identify multiple regions of ischemia. Both projections should be used routinely.


Basilar artery migraine 12 patients, with an attack recorded electroencephalographically.

Basilar artery migraine is distinctive disorder characterized by symptoms referable to dysfunction of brainstem structures in conjunction with more typical migrainous phenomena. Our experience with 12 cases, seen in a period of 10 years, is reviewed. In one instance, an attack of basilar artery migraine was captured by EEG, and appeared as a typical photoconvulsive response. More than half of our patients responded well to anticonvulsant drugs.


Human pneumatic tourniquet paralysis.

A 47-year-old woman experienced loss of strength, sensation, and sweating distal to a pneumatic tourniquet applied to her upper arm during operation for a Dupuytren contracture. Electrophysiologic tests showed a severe conduction block of sensory and motor fibers, well localized to the presumed lower margin of the tourniquet, with little evidence of axonal degeneration. Reversal of block began at 5 weeks and was complete in 6 months, coincident with almost full clinical recovery. Sweating was absent before 5 weeks and then returned, accompanied by a causalgic syndrome that did not disappear until recovery from the electrophysiologic block. The findings in this case correspond closely to pneumatic tourniquet paralysis in baboons, the pathophysiology having been recently defined. The relationship of autonomic changes to the electrophysiologic block suggest a mechanism for this patient's causalgia.


Cell-mediated immunity to measles, myelin basic protein, and central nervous system extract in multiple sclerosis. A longitudinal study employing direct buffy coat migration inhibition assays.

Cell-mediated immunity to myelin basic protein, to an extract of central nervous system white matter, and to measles virus nuclear core, was studied nine patients with multiple sclerosis in a serial longitudinal fashion using in vitro inhibition of buffy coat migration. The mean migration index to all antigens at various times before, during, and after exacerbation of multiple scelrosis in the patients did not differ from the index in a reference group of normal subjects. The incidence of inhibition of migration induced by central nervous system white matter and basic protein was greater than in serially studied normal subjects (p less than 0.05, p less than 0.2 less than 0.1, respectively) but bore no definite relation to clinical course.


The resolution of discrepancies in the reported incidence of primary brain tumors.

Population-based morbidity studies of primary intracranial neoplasms reveal a general pattern of age-specific incidence: a small childhood peak, followed by a taller peak between ages 50 and 80. One notable exception is Rochester, Minnesota, where there is a sustained increase in incidence with increasing age, together with higher age-specific rates than seen in data from other locations. Comparing data from Rochester and Connecticut reveals that the larger percentage of cases first diagnosed at autopsy in Rochester accounts in large part for these discrepancies and suggests that a substantial number of brain tumors remain undiagnosed in the elderly during life.


Spontaneous spinal epidural hematoma in an 8-year-old boy.

Spontaneous spinal epidural hematoma was confirmed by myelography in an 8-year-old boy. The hematoma was removed more than 21 hours after the onset of paraplegia, and there was no evidence of vascular malformation. The patient made a complete recovery.


Calcification in brainstem gliomas.

Calcification in brainstem gliomas is an unusual histologic and and radiologic finding. To date, radiologic evidence of calcification in these tumors has not been reported. The two patients described here had evidence of calcification on either computerized tomography (CT) or plain skull films. Increasing availability of CT scans may provide a more accurate estimate of the incidence of calcification in these tumors.


Cerebral cysticercosis.

Five patients with cerebral cysticercosis, two within the year preceding the date of this article, were seen at the New York Neurological Institute. The patients presented with mental changes, seizures, and symptoms of increased intracranial pressure, and had a history of having immigrated from an area endemic for cysticercosis. They were found to have parenchymal or intraventricular cysticercosis cysts. The interval from immigration to onset of symptoms was as long as 3 years. Plain radiograms of the skull and soft tissues, ventriculograms, and especially the CT scan, as well as the CSF examination, were useful in making the diagnosis. Surgical removal of an intraventricular cyst was curative in two patients and seizures were controlled with anticonvulsants in the other three.


Deformed erythrocytes in muscular dystrophies.

Because of previous reports of a possible correlation between echinocytogenesis and muscular dystrophies, we investigated the time-dependent development of echinocytes in the blood of normal subjects, patients, and healthy carries of Duchenne dystrophy. There was a quantitatively significant increase of echinocytes in patients and carriers.


Hypoglossal nerve palsy in infectious mononucleosis.

Involvement of the central nervous system is a rare complication of infectious mononucleosis. Isolated cranial nerve palsy is the least reported neurologic complication. We report a second case of hypoglossal nerve palsy associated with infectious mononucleosis, and review 20 other reported cases of cranial nerve palsies. Any cranial nerve may be involved. The onset of the palsy usually follows the diagnosis and clinical presentation of infectious mononucleosis. The prognosis for a complete recovery is excellent, although recovery may be protracted. The use of steroids does not appear to be etiologic, nor beneficial or deleterious in treatment.


Penicillamine-induced myasthenia gravis associated with antibodies to acetylcholine receptor.

A woman with rheumatoid arthritis was treated with penicillamine and developed myasthenia gravis. This drug-induced disease was associated with characteristic autoantibodies to acetycholine receptor. After discontinuing the drug, her symptoms improved and the antibody titers fell. Penicillamine is now being used much more frequently in the treatment of rheumatoid arthritis and it is likely that this complication will become more prevalent.


Prolonged encephalopathy with arsenic poisoning.

A case of prolonged reversible encephalopathy in a woman with arsenic poisoning is described. Previous descriptions of extended encephalopathy due to arsenic are rare.


Evaluation of the pituitary. Patients with suspected prolactin-producing tumors.

We have reviewed our experience in the radiographic and ophthalmologic evaluation of 1001 patients with symptoms suggesting the presence of a pituitary, prolactin-secreting adenoma. Twenty-seven patients had abnormal or suspicious radiographic examination of the sella turcica. Twenty-two of those had hyperprolactinemia. In only one instance was an abnormality noted on polytomography that was not seen on a conventional four-view study of the skull. Based on these findings, a four-view plain conventional radiographic assessment of the skull suffices as a screening procedure in patients with amenorrhea, galactorrhea, or both. Thin section tomography should be reserved to more thoroughly evaluate those patients with elevated serum prolactin concentrations and/or abnormal conventional radiographs. We found visual field testing to be of little value as an initial screening procedure in these patients.


Stage II carcinoma of the endometrium. An analysis of treatment.

An analysis of 41 patients with histologically documented Stage II adenocarcinoma of the endometrium treated between 1969 and 1974 is presented. The 3-year survival for all patients was 46%. Patients treated with radiation therapy alone (tandem, ovoids, and external radiation therapy) had 29% survival while patients treated with radiation therapy and surgery had a 71% survival. For all patients, survival by grade was 80% (Grade I), 36% (Grade II), and 20% (Grade III). Among those patients with recurrent disease, 40% of cases were in the pelvis while 20% were isolated distal recurrences. Patients with stromal invasion of the cervix had a 30% survival while patients without stromal invasion had a 67% survival. An analysis of these data, along with a review of the literature, reveals that 1) hysterectomy plays a critical role in survival, 2) invasion of the cervical stroma would appear to be a requisite criteria for the establishment of Stage II disease, and 3) aggressive radiation therapy with uterine packings (Heyman capsules) should be attempted in those patients who are not surgical candidates.


Galactorrhea, amenorrhea, hyperprolactinemia, and an empty sella.

Increased serum prolactin (hPRL) and increased volume of the sella turcica as detected by roentgenography are compatible with a pituitary adenoma. The empty sella syndrome can increase sella volume, but is usually associated with minimal, if any, endocrine dysfunction. The present case details a young woman with amenorrhea, galactorrhea, elevated serum hPRL, and roentgenographic evidence of an enlarged sella turcica. Pneumoencephalography with hypocycloidal polytomography is interpreted as both an empty sella, and evidence of a pituitary adenoma. The etiology and endocrine findings in the empty sella syndrome are discussed.


Fetal death during a negative contraction stress test.

This report describes a fetal death during a negative antepartum contraction stress test, without oxytocic stimulation, at 34 weeks' gestation in a woman with Class B diabetes mellitus.


Diagnostic value of androgen measurements in polycystic ovary syndrome.

A group of 51 women with a diagnosis of polycystic ovary syndrome (PCO) were investigated. They were further classified into PCO Type I and PCO Type II based on clinical and laboratory investigations. Serum levels of unbound (free) and total testosterone, testosterone binding globulin (TBG), and androstenedione were measured in these women and compared with values in normal women. Mean levels of all these steroids were elevated in women with PCO. No difference in adrogen levels was found between women with PCO Type I and PCO Type II. Serum unbound testosterone concentrations correlated better with the presence and severity of hirsutism than did the total testosterone.


Pharmacological alterations of coronary collateral circulation; implication to the steal-phenomenon.

Measurements of resistances were performed on different parts of coronary vessels, including spontaneous collaterals in anesthetized dogs, following ligation and embolization of the descending branch of the left coronary artery. The normal situation was compared with the state of maximal pharmacological dilatation. The pharmacological dilatation decreased the collateral resistance by 24% in spite of the fact that the collaterals supplied an infarcted area in this case; the precollateral resistance, which chiefly consists of large vessels was also diminished. The collateral perfusion pressure is not only dependent on the aortic pressure, but also on the flow rate in the corresponding large coronary vessel and thereby on the ratio of precollateral to postcollateal resistance. A decrease of the collateral perfusion pressure causes an insufficient perfusion of the area supplied by the collaterals only when the pressure fall is not compensated for by an adequate decrease in the collateral resistance and when the ratio of the collateral to the nutritive resistance increases. Thus, both, the extent of the pressure fall across the precollateral resistance and the dilating capacity of the collaterals determine whether is not a pharmacological dilatation of the coronary vascular bed results in an insufficient supply of an infarcted area, i.e. in a so called "Steal-phenomenon". The results show further, that the given physical model of the microcirculation satisfactorily approximates the observed behaviour of the vascular system.


Effect of denervation and ouabain on the response of the resting membrane potential of rat skeletal muscle to potassium.

The effects of denervation and ouabain on the relationship between resting membrane potential (EM) and extracellular potassium concentration were determined for rat soleus (SOL) and extensor digitorum longus (EDL) muscles. At concentrations above 20 mM for both SOL AND EDL fibres the relationship could be described adequately by the Nernst equation. Denervation resulted in reduction of EM and a decrease in the slope of the relationship between EM and potassium concentration. 10(-3) M ouabain produced the same effects as denervation. The results are discussed in relation to the alterations in membrane permeability previously shown to occur as a consequence of denervation. It is concluded that the low EM of denervated muscle is the result of an increase in membrane permeability to sodium.


Magnesium handling by the papilla of the young rat.

In a recent study it was found that in Mg loaded rats, the fraction of filtered Mg (% E Mg) recovered in the bend of the loop of Henle of papilla was greater than the filtered load. However, the site of this Mg addition was unspecified and could be either the juxtamedullary proximal tubule, the pars recta, or in the papilla, the descending limb of the loop of Henle. In order to investigate the movement of Mg in the various structures of the papilla, we have studied: 1. The transport of this electrolyte along the collecting duct. 2. Its relative concentration in the loop of Henle and in the adjacent vasa recta. The experiments have been performed in hydropenic and Mg loaded rats. In the collecting duct, the inulin and Mg concentrations increase proportionally, indicating an absence of any transport of Mg along this part of this nephron. In the vasa recta of the accessible papilla, the capillary over peripheral plasma Mg ratio (C/UF Mg) in hydropenia and after Mg loading [1.88 +/- 0.15 (ES) and 2.89 +/- 0.25] were significantly lower than the corresponding TF/UF Mg in the adjacent loops of Henle (2.90 +/- 0.17 and 4.04 +/- 0.37). This finding reduces the possibilities of a Mg passive diffusion from the capillaries to the tubular lumen, unless the electrical potential of the descending limb is more negative than -5 mV. The hypothesis of an active secretion, or a passive diffusion of Mg in the deep proximal tubule, in the pars recta, or in the early non accessible descending limb constitutes the other alternative.


Sugar transport by brush border membrane vesicles isolated from human small intestine.

Uptake of D- and L-glucose, and fructose by purified brush border membrane vesicles isolated from human small intestine was studied using a rapid filtration technique. The uptake of D-glucose by the vesicles was osmotically sensitive and represented transport into an intravesicular space and not binding to the membranes. Transport of both, D- and L-glucose was inhibited by phlorizin. Uptake of D-fructose into the brush border vesicles was not stimulated by sodium. In the presence of a sodium gradient D-glucose was taken up 5 times faster than L-glucose. The amount of D-glucose transported into the vesicles in the presence of a sodium gradient was transiently higher than the amount of D-glucose taken up at equilibrium (over-shoot). D-Glucose transport was stimulated only by a sodium gradient; other monovalent cations had no effect. In the presence of a sodium gradient D-glucose transport was increased by the nearly impermeable anion sulfate as compared with uptake of D-glucose in the presence of a sodium chloride gradient. This indicates an influence of the electrical membrane potential on the sodium coupled non-electrolyte transport.


Effects of total body core cooling on heat production of conscious goats.

Experiments were performed to investigate the effect of general body core cooling on heat production at various air temperatures between +1 degree C and +56 degrees C in conscious goats. An intravascular heat exchanger (IVHE) was used to alter body core temperature independently of air temperature. Heat loss via the IVHE caused a fall in body core temperature, the extent of which depended on the rate of extraction and air temperature. Irrespective of air temperature the decrease in body core temperature resulted in shivering and an increase in heat production, which eventually balanced the heat loss. During steady state conditions the extra heat production was approximately equal to that lost via the IVHE. The threshold body core temperature at which heat production increased in response to central cooling did not significantly alter with air temperature. However, the slopes of the curves describing this response were smaller at higher than at lower air temperatures, which indicated that central thermosensitivity decreased with increasing air temperature. Irrespective of air temperature the threshold temperatures for shivering were higher and the slopes of the curves were steeper than those previously found with combined cooling of the hypothalamus and spinal cord in the same species which indicated the existence of central thermosensors outside the above two mentioned areas.


In vivo measurement of carbon dioxide tension with a miniature electrode.

A commercially available catheter type electrode with which PCO2 can be continuously measured in vivo and in vitro gave progressively less accurate results the longer the measuring period was extended. This proved to be due to temperature effects and a change in sensitivity with time. A correction procedure for these effects was developed which was based on two observations. 1. The relationship between temperature and the logarithm of the sensitivity of the electrode-amplifier combination was linear and virtually identical for 9 electrodes: 8% change in sensitivity for a deviation of 1 degree C from the temperature during calibration. 2. The change in sensitivity due to drift of the electrode output is approximately a logarithmic function of time: 1 h after calibration all electrodes exhibited a decreased sensitivity, varying between 0.3 and 16.7%. The drift effect can be dealt with by repeated calibrations, preferably at 1 1/2 h intervals. The adequacy of the correction procedure was assessed in in vivo measurements in cats and dogs. The mean PCO2 difference between the in vivo measurement, corrected for temperature and drift, and samples analyzed with a conventional electrode, was 0.005 kPa (0.04 mm Hg) with a standard deviation of 0.187 kPa (1.39 mm Hg).


A fiberoptic reflection oximeter.

A catheter tip oximeter is described consisting of a cardiac catheter containing optical fibers, and incandescent light source, a light detection unit and a processing unit. Half of the optical fibers guide the light to the blood at the tip of the catheter, the other half the backscattered (reflected) light to the detection unit. The detection unit contains a dichroic mirror, transmitting most of the light with lambda less than 800 nm and reflecting most of the light with lambda greater than 900 nm, thus splitting the light into two beams. These pass through interference filters with nominal wavelengths of 640 and 920 nm respectively, and are focused on silicium barrier layer photocells. The photocell signals are amplified and fed into a divider giving the ratio of measuring (R640) and compensating (R920) photocell output. The relationship between log R640/R920 and oxygen saturation is represented by a slightly curved line. The relation may be linearized by subtracting a constant voltage from the divided output before taking the logarithm. The slope of the calibration line is dependent on the total haemoglobin concentration. Nonetheless an average calibration line can be used between 70 and 100% oxygen saturation. For 78 measurements of pig blood samples in this range (haemoglobin concentration between 96 and 161 g.1(-1)), the standard deviation of the difference between the fiberoptic oximeter and a Radiometer OSM1 oxygen saturation meter was 1.9% saturation, for 152 samples over the entire saturation range the standard deviation of the difference was 3.1% saturation. The influence of the flow velocity of blood on the light reflection depends on wavelength as well as on oxygen saturation. Therefore, complete compensation for the flow effect is not possible by simple means.


Estimation of the number of normal subpopulations in an heterogeneous sample and of their parameters. A recurrent method applied to neurobiology.

A method is proposed to estimate the number of subpopulations which compose a heterogeneous experimental population. The method consists of reconstructing a population sample by adding computed subpopulations, postulated to be independent. The assumption is made that each subpopulation fits a normal distribution; the method may also be generalized to other distributions laws; each subpopulation can thus be entirely defined by its mean, variance and relative weight. Recurrent adjustments of number and parameters of subpopulations are carried out in order to minimize the difference between synthetized and experimental populations. This difference was measured by the quadratic distance chi2 between the two populations. Mean, variance and weight of the computed population must then be close to those of the experimental population in order to consider the results as acceptable. This method is discussed with regard to others proposed in the literature.


EEG effects of the ventricular cerebrospinal fluid of rabbits submitted to thalamic stimulation.

Electrical stimulation of the "somnogenic" thalamic area of Hess in chronic rabbit donors significantly increases the EEG delta activity against controls (41%; p less than or equal to 0.05). In recipient rabbits infused with cerebrospinal fluid (csf) from these donors, the delta increase against control rabbits (26%) suggests a sedative activity of the infused csf, able to counteract the waking tendency in chronic recipients.


Hyperthermic effects of arachidonic acid, prostaglandin E2 and F2alpha in rats.

The aim of the present study was to investigate the possibility that endotoxin fever in rats is mediated by arachidonic acid (AA) which in turn is converted to the active metabolites such as prostaglandin (PG) E2, PGF2alpha, thromboxane A2 (TxA2), or prostacyclin (PGI2). Evidence is presented indicating that PGE2 induces fever (not hyperthermia) by acting on the anterior hypothalamic preoptic area. Conversely, both PGF2alpha and AA produce mutually similar hyperthermia and there is no correlation between their microinjection sites in the diencephalon and the observed hyperthermic response. In addition, evidence is presented suggesting that involvement of other metabolites of AA, namely TxA2 and PGI2 in the mediation of endotoxin fever in rats seems unlikely. Only PGE2-induced fever is significantly similar, consistent with the parameters of this study, to endotoxin-induced fever in rats. AA-induced hyperthermia is probably brought about by increased levels of PGF2alpha or both PGF2alpha and PGE2 in the hypothalamus following AA injection. It seems highly unlikely that endotoxin produces fever in rats through the increased availability of free AA or through the activation of the PG endoperoxide synthetase in the hypothalamus. The mechanism by which endotoxin may increase PGF2 levels in the rat hypothalamus remains unknown.


Flux of metabolic fuels during starvation in the rat.

Rats were starved for 6 days to determine whether the "nitrogen sparing" observed during starvation in humans was also present in rats. The urinary nitrogen excretion decreased on the first day, probably due to metabolism of remaining dietary protein. From the second day of starvation to the end of the starvation period, the urinary nitrogen excretion increased progressively. The hepatic glycogen stores were depleted at the end of the first day. The blood glucose concentration remained constant throughout starvation period except for a 15% decrease on the first day. There was increased mobilization of lipid stores, starting on the first day, reflected by an increase in the blood free fatty acids, glycerol and ketone body concentrations. These metabolite concentrations began to increase on the third and fourth day which probably reflected depleted fat stores since no visible body fat was observed by the fourth day. The data indicate that the rat does not spare body protein during starvation, probably because it depletes its glycogen and fat stores rapidly and must then depend on body protein as the major fuel for energy metabolism.


Medullary and carotid chemoreceptor interaction for mild stimuli.

The interaction of medullary and carotid chemoreceptors during mild stimulation was investigated in 44 experiments on 6 chloralose-urethane anesthetized mongrel dogs using a donor-perfused, bilateral carotid sinus preparation. The donor dog breathed hypoxic mixtures (average PaO2 of 78 mm Hg) and the experimental animal breathed hypercapnic mixtures (average PACO2 of 49 mm Hg) in order to separately or simultaneously stimulate both chemoreceptor areas at low levels. After 4 min, the changes of tidal volume (VT), respiratory rate (f) and minute ventilation (VI), as a percentage of the control value, were compared to test whether the sums of the changes for separate stimuli were the same as for simultaneous stimuli, i.e. additive chemoreceptor effects. The simultaneous stimuli had significantly (P less than 0.05) greater responses for VT (19% greater than 5%) and VI (42% greater than 13%), but not for f (23% = 9%). Stepwise multiple regression studies of the response/control ratios on the blood gas values showed that multiplicative interaction terms accounted for more of the variance than additive terms for VT, f and VI and yielded equations which had overall significant slopes. We conclude that this evidence demonstrates that the two chemoreceptor effects combine synergistically at low levels of stimulation.


Interactions of behavioral and autonomic thermoregulation in heat stressed pigeons.

The interactions of behavioral and autonomic thermoregulation in pigeons during ambient heat load were studied by simultaneous measurements of instrumental response rate for cold air reinforcement and respiratory rate. When providing sufficient reinforcement-magnitudes, deep body temperatures were stabilized, due to a linear increase of response rate with ambient loads from 40-60 degrees C, without involving an increase in respiratory heat dissipation. This was effected by maintaining the temporal mean of air temperature and consequently of all skin temperatures at a level independent from load temperature (Fig. 3). When the efficiency of instrumental thermoregulation was limited by reducing the reinforcement-magnitude, not only the instrumental response rate increased, but in addition body temperatures and subsequently respiratory rate rose with the thermal load. Thus a positive correlation between body temperatures and response rate and a simultaneous increase of autonomic heat defence activities characterize incomplete behavioral thermoregulation. The instrumental response rate rapidly followed changes of external load temperature without preceding changes of core temperatures or skin temperatures at well feathered areas (Fig. 6). These findings suggest that the input signal controlling instrumental thermoregulatory behavior is related to the rate of change of temperatures at exposed areas of the body shell, whereas the autonomic heat defence response follows the steady displacements of body temperatures. This points to an important difference between the input signals controlling behavioral and autonomic heat defence in the pigeon.


Distribution of the myocardial tissue PO2 in the rat and the inhomogeneity of the coronary bed.

The structural inhomogeneity of the myocardial capillary bed is stimulated by microcirculatory units (MCU's) in a diffusion model. This stimulation is based on MCU's in which the arrangement of the capillary ends (concurrent structure, partial and total countercurrent (structure, helical structure) as well as the structure and supply parameters are varied. The variation of these parameters is based on own measurements of the intracapillary HbO2 saturation as well as on the following parameters from the literature: frequency distribution of capillary distance and capillary radius, mean capillary length or capillary section length respectively, arterial and mean venous PO2, mean coronary blood flow, mean O2 consumption and diffusion conductivity. The analysis of O2 supply of the normoxic rat heart shows that an O2 diffusion shunt is obligatory except of MCU's with an extremely large capillary distance or with a concurrent capillary structure. Therefore the minimal tissue PO2 lies at the level of the capillary venous PO2 of a MCU. The maximum of the total PO2 frequency distribution in the normoxic rat myocardium lies at 25 +/- 5 mm Hg, i.e. above the mean venous PO2 (20 mm Hg). Tissue PO2 values between 0 and 5 mm Hg amount to 0.5% i.e. they are extremely rare. Tissue PO2 values of 0-1 mm Hg represent less than 0.2%.


Modifications by stretches of the mechanical response of isolated cerebral and extracerebral arteries to vasoactive agents.

Length-tension relationship was compared in helically cut strips of canine cerebral, coronary, mesenteric, renal, and femoral arteries. Tension developed progressively by increasing the stretch; with the same strain, a greater passive tension developed in cerebral than in extracerebral arteries. The peak active tension developed by serotonin (cerebral, coronary), norepinephrine (mesenteric, renal and femoral) or K+ (coronary) was obtained at a resting tension of 1.5 g (other than coronary) or 2.0 g (coronary). Papaverine (10(-4) M) caused a relaxation in cerebral arterial strips contracted with serotonin to a level lower than that prior to the addition of serotonin, the relaxation from the initial level of tension being related directly to the stretch applied. The relaxing effect of adenosine was related directly to stretches of cerebral arterial strips. It seems likely that a rise of intra-arterial pressure effects a greater increase in the wall stiffness in cerebral than in extracerebral arteries. The responsiveness to vasoconstricting and vasodilating agents of both cerebral and extracerebral arteries appears to increase when the arteries are distended.


Current-voltage relations in ventricular muscle preparations from different species.

Current-voltage relations were determined in ventricular muscle preparations from dog, sheep, pig, guinea pig, bull and cat hearts. The single sucrose gap voltage clamp method was used to apply 2 s steps or slow speed voltage ramps (3-4 mV/s). 1. The current-voltage relations obtained with 2 s steps were similar to those obtained with ramps. 2. Negative slope regions were readily apparent in the current-voltage relations of preparations from all species except cat although the latter did display marked anomalous rectification. 3. Increasing the external potassium concentration from 3 to 10 mM increased the slope of the current-voltage relation around the resting potential and resulted in the "crossing-over" and "crossing-back" of the relations if all tissues. 4. The two extreme cases of bull (marked negative slope region) and cat (no negative slope region) were compared with regard to transgap intracellular and extracellular resistances; they were quite similar. This suggests that the current-voltage relations reflect differences in membrane properties rather than, for example, different proportions of non-membrane leakage current. 5. In bull ventricular preparations, the application of D-600 (2 X 10(-6) M), 30 min) had only a small effect on the current-voltage relation. In contrast, cesium (10-20 mM) nearly abolished the negative slope region suggesting that this characteristic of the current-voltage relation is due to potassium channel rectification. 6. Possible explanations for action potential durations in bull ventricular fibres being 50 to 100% longer than in cat are considered.


Respiratory oscillations of the arterial PO2 and their effects on the ventilatory controlling system in the cat.

The respiratory oscillations of the arterial PO2 were measured in paralyzed, artificially ventilated cats by a small (1.2 mm) fast-responding catheter oxygen electrode. The amplitude of these oscillations could be changed independently of the mean PA,O2n by a specially designed respirator circuit. deltaPaO2 was shown to increase with increasing tidal volume or decreasing frequency of the respirator, and with increasing mean PaO2. The amplitude of the oscillations was attenuated considerably from the left atrium to the aorta. No attenuation occurred from the aorta to the carotid artery, provided that the blood flow in the carotid artery was not impeded. The measured attenuation of the oscillations was compared to that calculated by Yokota and Kreuzer (1973) and found to be quite different. The output of the ventilatory controlling system of the cat was measured from the quantified phrenic nerve activity. When only deltaPaO2 was changed at a constant level mean PaO2, the quantified phrenic nerve activity did not change, indicating that the amplitude of the oscillations does not influence the ventilatory controlling system. In vagotomized animals, the periodicities of the oscillations and the phrenic nerve activity were completely dissociated. From the fact that no Cheyne-Stokes type of breathing occurred, it was concluded that the effect of timing is negligible.


Thermally-induced cutaneous sympathetic activity related to blood flow through capillaries and arteriovenous anastomoses.

In the ears of anaesthetized rabbits cutaneous efferent sympathetic nerve activity (SkNA) and blood flow (Q) to capillaries have been measured during various thermal treatments. Warming the spinal cord or skin of the body midside caused a marked decrease in SkNA but capillary Q increased only slightly. Exposure to a warm environment or localized warming of the ear alone induced either a decrease, an increase, or no change in SkNA, but capillary Q always increased markedly. The usual slight increase in capillary Q during spinal warming, was abolished by preventing the usual marked increase in skin temperature. When the spinal cord of the conscious rat was warmed, a marked increase in temperature of the tail (which contains arteriovenous anastomoses, AVA's) indicated dilatation, whereas there was no change in ear temperature (where there are no AVA's). When these results are considered together with recently defined differential influences of reflex and direct effects of temperature on blood flow through cutaneous AVA's and capillaries, it is concluded: (1) That thermally-induced reflex changes in skin blood flow are mediated via sympathetic nervous action on AVA's; (2) Changes in blood flow evoked by direct heating take place through the capillaries, not the AVA's, quite independently of SkNA.


Intracerebral gas partial pressure changes under vasoactive drugs. A mass spectrometry study.

An original technique based on mass spectrometry has been used to measure simultaneously in undrugged, freely-breathing animals local PO2 and PCO2 in the brain (caudate nucleus) and arterial PO2 and PCO2 in the aorta. Injection of vasoactive drugs brought about significant modifications of the partial pressures of the physiological gases in the brain. The origin of these variations was discussed, based on the combination of 3 possible factors: cerebral vascular changes, systemic metabolic changes (PaO2 and PaCO2) and local metabolic changes. It was demonstrated that local variations of PCO2 cannot be held to be responsible for the modifications of cerebral blood flow induced by papaverine or the sympathomimetic drugs.


Effects of locally applied chemicals on transretinal potential and horizontal cells in the isolated carp retina I. Amino acids.

Experiments were performed on isolated retinas of teh carp (Cyprinus carpio) to investigate the effects of locally applied amino acids on the transretinal potential and the membrane potential of horizontal cells. A minute quantity of each solution of an amino acid was applied locally at different layers by means of pressure-microinjection. The responses were induced by alternating central and annular stimuli of white light. Amino acids applied locally at the distal layer (receptor surface or outer plexiform layer) in the centrally stimulated area, caused, at concentrations of 25--50mM, rapid changes in the light-induced potential, whereas those microinjected into the inner plexiform layer did not. When applied locally at the distal layer, amino acids abolished the proximal PIII response and reduced the amplitude of S-potentials, particularly in response to a central stimulus. However, the resting potential of horizontal cells was depolarized only slightly by acidic amino acids. The results suggest that the passive membrane properties of horizontal cells are not altered significantly by the amino acids applied. Differential susceptibilities of the PII component to acidic and neutral amino acids were found; the former did not change or, in some cases, enlarged, whereas the latter abolished it. Possibly, neutral amino acids interfere with a neural mechanism generating the PII component.


Asymmetry of the chloride transport system in human erythrocyte ghosts.

The concentration dependence of the unidirectional chloride flux and the inhibition of the unidirectional chloride flux by sulfate were studied in human red cell ghosts. The concentration dependence of the unidirectional chloride flux and its inhibition by sulfate were asymmetric. The unidirectional chloride flux can be saturated from the inner and from the outer membrane surface. For the inner membrane surface, lower chloride half-saturation constants were obtained than for the outer membrane surface. The inhibition of the unidirectional chloride flux by sulfate is competitive. In contrast to the chloride half-saturation constants, the inhibition constants of sulfate for the inner membrane surface were higher than the inhibition constants of sulfate for the outher membrane surface. Either there are fixed anion binding sites at the inner and at the outer membrane surface which control the access of anions to a pore, or there is a mobile carrier which is in contact with both membrane surfaces. The asymmetry of the concentration response and of the inhibition of the unidirectional chloride flux suggest that the anion binding sites at the inner and at the outer membrane surface differ with respect to their affinities for chloride and for sulfate. Alternatively, the asymmetry of the chloride transport system could indicate an asymmetric distribution of a mobile anion carrier across the erythrocyte membrane.


[Treatment of insulin-resistant form of diabetes mellitus by intravenous droplet infusion of insulin].

Four patients with an insulin-resistant form of diabetes mellitus were treated with intravenous droplet injections of swine insulin. There was revealed a rapid reduction of the 24-hour requirement in insulin and of the antiinsulin antibody titre. The method proved to be effective for the treatment of patients with "immune" and "nonimmune" forms of insulin resistance. The method is recommended for the treatment of patients with diabetes mellitus decompensation.


Dopaminergic mediation of beta-endorphin-induced catalepsy.

Acute intracisternal administration of human beta-endorphin produced catalepsy and increased striatal concentrations of 3,4-dihydroxyphenylacetic acid (DOPA) and homovanillic acid (HVA). All of these effects were blocked by naloxone. Apomorphine, a dopamine receptor antagonist, also prevented beta-endorphin-induced catalepsy and the increase in striatal DOPAC and HVA. The combination of subcataleptic doses of haloperidol and beta-endorphin produced catalepsy and large increases in striatal DOPAC and HVA. These data provide evidence for a role for nigrostriatal dopamine neurons in beta-endorphin-induced catalepsy. The apparent increase in striatal dopamine turnover following beta-endorphin administration may be compensatory.


Pathways of propranolol metabolism. Use of the stable isotope twin-ion GC-MS technique to examine the conversion of propranolol to propranolol-diol by 9000g rat liver supernatant.

The metabolic conversion of propranolol to propranolol-diol [1-(1-naphthyloxy)-2,3-propyleneglycol] by rat liver 9000g supernatant was demonstrated to proceed through the intermediate 3-naphthyloxy-2-hydroxypropionaldehyde. Using side chain deuterated propranolol-d5 as substrate, propranolol-diol-d4 was produced, indicating an obligatory aldehyde intermediate. Analysis of desisopropylpropranolol obtained in the same incubation showed no loss of deuterium indicating that the possibility of rapidly tautomerizing imine intermediate did not make a significant contribution in this metabolic conversion. Desisopropylpropranolol, added in small amounts to the incubation mixture is more rapidly converted to the propranolol-diol than is propranolol, indicating that the major pathway of conversion of propranolol to its diol metabolite is through the desisopropylpropranolol intermediate.


Plasma vitamin A transport and visual dark adaptation in diseases of the intestine and liver.

Quantitative analyses of plasma concentrations of retinol binding protein (RBP), prealbumin and total proteins were performed in normal subjects and in forty-two patients suffering from diseases of the intestine and liver. The visual dark adaptation ability (DAA) was also assessed. Reduction of DAA and of RBP and prealbumin levels was noted in patients with chronic liver disease and fat malabsorption. In sixty-eight patients with intestinal diseases the RBP concentration seemed to be reduced in relation to the degree and duration of steatorrhoea. Furthermore, inflammatory activity, as revealed by laborabory tests, markedly reduced the RBP level. Treatment with vitamin A increased the RBP and prealbumin concentrations and restored the DAA to normal in patients with malabsorption but normal liver function. In patients with liver disease reduced DAA and serum RBP values were not affected by vitamin A therapy. Only at RBP concentrations below half the normal was impairment of the dark adaptation observed, suggesting that serum RBP is a more sensitive indicator of vitamin A deficiency than measurement of dark adaptation.


Phenylalanine depletion for the management of phenylketonuria: use of enzyme reactors with immobilized enzymes.

Multitubular enzyme reactors with immobilized phenylalanine ammonia lyase were tested in vitro and in vivo for depletion of phenylalanine in circulating blood. Sustained reduction of phenylalanine was achieved in less than 30 minutes. A 50% decrease of phenylalanine was obtained with a 2-hour application of enzyme reactors and was maintained for more than 2 days. Similar enzyme reactors have therapeutic potential for temporary management of phenylketonuric patients when their circulating phenylalanine becomes exceedingly high because of infection, fever, or pregnancy.


Formation of mutagens in beef and beef extract during cooking.

Mutagens, distinguishable from benzo[a]pyrene and from mutagenic amino acid and protein pyrolysis products, are formed when ground beef is cooked in a home hamburger cooking appliance or when beef stock is concentrated, by boiling, to a paste known commercially as beef extract. "Well-done" hamburgers contain about 0.14 part per million of the mutagens, and beef bouillon cubes which contain beef extract about 0.1 part per million. Since such mutagens may be potentially carcionogenic and are formed during ordinary cooking procedures, their occurrence raises questions about possible risks to human health.


Histidine-rich protein as a model malaria vaccine.

Ducklings were successfully immunized against Plasmodium lophurae with a purified and characterized histidine-rich protein as antigen. The use of adjuvant is not required for this protective effect, and immunity can be passively transferred with serum.


Phagocytosis in the retinal pigment epithelium of the RCS rat.

The retinal pigment epithelium of RCS rats, previously thought not to phagocytize photoreceptor outer segments, exhibited a peak of phagocytosis in vivo when animals were kept under conditions of cyclic lighting (12 hours of darkness and 12 hours of light). The peak occurred at 1 hour after the onset of light, with maximum and minimum levels of phagocytosis averaging about 5 percent of that found in  the pigment epithelium of Osborn-Mendel rats used as a control. Eyecups that were obtained from Osborn-Mendel rats and maintained for up to 3 hours in organ culture demonstrated levels of phagocytosis that were sevenfold greater than those of unincubated controls. Likewise a tenfold increase occurred in incubated as opposed to unicubated RCS eyes, raising the possibility that phagocytosis could be experimentally stimulated in vivo.


Cutaneous angiosarcoma of the hip.

An elderly patient is presented who developed a fatal angiosarcoma of the hip about ten years after surgery and radiation for a uterine malignancy. She developed a metastasis of the uterine tumor, requiring additional radiation, which led to aseptic necrosis of the hip and chronic joint and soft tissue infection of the hip from a joint prosthesis. Subsequently she developed chronic lymphedema of the hip and finally the cutaneous angiosarcoma in this area. Any or all of these factors might bear a causative relationship to the angiosarcoma, but none can be proved.