Cognitive processes and information seeking concerning an environmental health threat.

Interviews with 577 college students in New Jersey, a state with a high reported rate of cancer, were conducted to assess the ways in which they conceptualize this issue and to determine how they would react when offered an opportunity to obtain factual information about the cancer threat. Those who appeared to be most in need of information were found to be the least likely to seek it. Of students who were undecided whether or not living in the state would increase their chance of getting cancer, only 25.7 percent requested the information, compared to 49.1 percent of students who acknowledged the increased risk and 43.9 percent of those who denied the risk. Individuals who had not known previously about the high cancer rates were less likely to request information (37.9 percent) than those who had known (47.9 percent), and they used different arguments to justify their denial of risk. The specific arguments used by students to explain why they denied that there was a threat or why they planned to stay in the state in spite of the risk were generally unrelated to information seeking.


Rfv-1 and Rfv-2, two H-2-associated genes that influence recovery from Friend leukemia virus-induced splenomegaly.

Two genes, Rfv-1 and Rfv-2, that influence recovery from Friend virus leukemia have been identified within or adjacent to the mouse major histocompatibility gene complex (H-2). Rfv-1 was determined to be in the H-2G or H-2D regions by testing of mice with recombinations both to the left and right of these regions. Rfv-2 was located either in the H-2K or H-2I regions or in the Tla region. The Rfv-2 effect was not seen in the high recovery H-2D(Rfv-1)b/b mice. This could be an indication that this gene is weaker than Rfv-1 in its influence on leukemia. The influence of H-2 on recovery from leukemia appeared to operate in a gene-dose fashion (H-2b/b greater than H-2a/b greater than H-2a/a).


Effect of liposomal model membrane composition on immunogenicity.

We have examined the effect of composition on the immunogenicity in mice of liposomal model membranes sensitized with dinitrophenyl-epsilon-aminocaproyl-phosphatidylethanolamine (DNP-Cap-PE) derivatives. Neither cholesterol content nor incorporation of exogenous charged amphiphile (dicetylphosphate, stearylamine) exerted a significant influence on the in vivo anti-DNP response as measured by the appearance of direct plaque-forming cells in the spleen. Similarly, the nature of the fatty acids (saturated vs unsaturated) present in DNP-Cap-PE had no effect. In contrast, the nonpolar region of the basic phospholipids comprising the liposomal bilayers played an important role as revealed by a comparative study of model membranes prepared with beef sphingomyelin (SM), egg phosphatidylcholine (PC), and synthetic distearoyl-, dimyristoyl-, dilauroyl-, and dioleoyl-phosphatidylcholines (DSPC, DMPC, DLPC, DOPC). Thus, liposomes with a large content of phospholipids possessing a high transition temperature (e.g., beef SM, DSPC) were more immunogenic than those containing phospholipids of low transition temperature (e.g., egg PC, DOPC). This correlation held for both unsonicated and sonicated liposomes. These findings may have a bearing on the phenomenon of membrane-localized antigen expression.


Comparison of the homogeneous, primary anti-dextran B1355 antibody raised in BALB/c mice with protein 104E.

The primary antibody response to dextran B1355 in BALB/c mice is largely a homogenous IgM antibody. This antibody appears to be similar if not identical to the myeloma protein, protein 104E, for the following reasons: a) isoelectric focusing of the 7S monomers, separately and together in co-isoelectric focusing, give the same pattern, both in the presence and absence of 4M urea; b) the inhibition of lysis of the dextran-coated SRBC by specifically purified anti-dextran antibody and by protein 104E required essentially the same concentration of dextran B1355. This similarity was further demonstrated by plaque assays with dextran-coated SRBC, in which the formation of plaques was inhibited by free dextran. Inhibition of plaques produced by both types of cells required essentially the same concentration of dextran B1355. On these bases, there appears to be no difference in properties (or in structure) between the myeloma protein and the induced antibody.


Immunologic responses to Candida albicans. III. Effects of passive transfer of lymphoid cells or serum on murine candidiasis.

Passive transfer of immune serum gave a significant degree of protection against deep seated candidiasis in mice. Repeated attempts to transfer resistance by the transfer of sensitized lymphoid cells gave negative results, even though cutaneous delayed hypersensitivity was transferred by the cells. The results suggest that cell-mediated immunity is not of primary importance in this model of murine candidiasis, and that humoral immunity contributes to protection.


Inhibition of tumor growth mediated by lymphocytes sensitized in vitro to a syngeneic murine teratocarcinoma 402AX.

TerC, a cell line derived from a strain 129 teratocarcinoma 402AX, was used to sensitize syngeneic 129 (H-2bc) splenic lymphocytes in vitro. The effector cells generated inhibited in vitro growth of TerC as measured by an 125I-IUDR ost-labeling technique. It was also shown, with a modified Winn assay, that the sensitized cells were effective in preventing TerC growth in vivo. The effector lymphocyte was nonadherent to nylon wool was sensitive to anti-Thy-1.2 + C, and was phenotypically Ly 1-2+. The anti-TerC effector T lymphocytes were not functional in a 51Cr-release assay. However, this failure to lyse appears not to be due to some intrinsic membrane resistance since both BCG and ConA-activated killers were able to lyse TerC. The TerC-sensitized lymphocytes displayed no H-2 restriction and were able to growth inhibit in vitro a wide range of tumorigenic cell lines, e.g., P815 (H-2d), EL-4 (H-2b),Sal (H-2a), and BALB/c (H-2d) 3T12. Mouse blastocyst cell lines were also inhibited. BALB/c 3T3 and mouse fibroblast cell strains were not growth inhibited. Thus, it appears that oncofetal antigens expressed on TerC are capable of initiating a cell-mediated response and that these antigenic specificities are shared by many transformed cell lines.


Generation of suppressor lymphocytes during sensitization in culture against a syngeneic tumor: affinity chromatography on insolubilized histamine.

We investigated the effect of depletion of histamine-binding lymphoid cells on immunological properties of lymphocytes sensitized in culture against tumor cells. C57BL/6 spleen cells that were sensitized in vitro on monolayers of the syngeneic Lewis lung carcinoma (3LL) became cytotoxic to the tumor cells in vitro after 3 to 5 days of sensitization. Sensitized cells harvested after 4 days of sensitization occasionally enhanced tumor growth in vivo. Fractionation of the sensitized lymphocytes over insolubilized histamine-rabbit serum albumin-Sepharose (HRS) columns decreased or abolished the enhancing activity in vivo and specifically increased the in vitro cytotoxic activity of the depleted lymphocytes. A similar increase in the cytotoxic activity of HRS-fractionated cells was observed in an allogeneic combination of C57BL spleen cells sensitized against C3H fibroblasts. The effect of HRS chromatography on the in vitro cytotoxic activity increased with prolonged incubation of the depleted effector cells with the target cells.


Depression of mitogen response in spleen cells from reticuloendotheliosis virus-infected chickens and their suppressive effect on normal lymphocyte response.

Spleen cells and peripheral blood lymphocytes from chickens infected with reticuloendotheliosis virus (REV) were depressed in their responsiveness to phytohemagglutinin (PHA). When spleen cells from uninfected chickens were co-cultured with spleen cells from chickens infected with REV at 2 weeks of age, the PHA response by the normal cells was completely suppressed. Although spleen cells from chickens infected with REV at 6 or 9 weeks of age were also suppressed in their ability to respond to PHA, they did not suppress the mitogenic response of normal cells in mixed cultures.


A caucasoid pedigree demonstrating the transmission of a Gm 1,2,17;5,13,14 haplotype.

Data illustrating the inheritance of a Gm1,2,17,5,13,14 haplotype in a Caucasian family are presented. The mother and two children are heterozygous for this unusual haplotype. The possible origin of the haplotype is discussed.


Evidence that blood group A antigen on lymphocytes is derived from the plasma.

Serum from group O volunteers, who had been injected with porcine A blood group substance, was used in lymphocytotoxicity tests. Positive reactions were obtained only with lymphocytes of group A secretors; the strongest reactors were Le(a--b--). The same group O sera reacted with group O lymphocytes which had been exposed to a glycosphingolipid fraction prepared from the plasma of A,Le(a--b--) secretors. These reactions were specifically inhibited by A substance. It is suggested that, unlike the A antigen on red cells, the A antigen detected in lymphocytotoxicity tests is entirely derived from the plasma.


Complement fixation antibodies to glycosphingolipids in sera of rare blood group p and Pk phenotypes.

Blood group P antigen and Pk antigen were recently identified as glycosphingolipid globoside, GalNAc(beta, 1 leads to 3)Gal(alpha, 1 leads to 4)Gas(beta, 1 leads to 4)Glc(beta, 1 leads to 1)ceramide, and trihexosylceramide, Gal(alpha, 1 leads to 4)Gal(beta, 1 leads to 4)Gld(beta, 1 leads to 1)ceramide, respectively (Naiki & Marcus, 1974). The presence of antibodies to both antigens in the sera from rare p donors and antibodies to P antigen in the serum from a rare Pk donor were first demonstrated by the complement fixation test with the optimal antigen preparations containing each purified glycoplipid, lecithin and cholesterol. In the serum from a p donor, most of antibody population of anti-P was IgM and was cross-reacted to Forssman glycolipid, GalNAc(alpha, 1 leads to 3)GalNAc(beta, 1 leads to 3)Gal(alpha, 1 leads to 4)Gal(beta, 1 leads to 4)Glc(beta 1 leads to 1) ceramide, but the rest of the anti-P antibodies and most of anti-Pk antibodies were IgG and had marked specificities for globoside and trihexosylceramide, respectively.


Intercellular adhesiveness of H-2 identical and H-2 disparate cells.

Using a 2 X 2 design, the collection rates of cells from radioactively labelled single-cell suspensions on cell-coated collecting surfaces were tested for a possible H-2 effect on intracellular adhesiveness. By a statistical procedure, the undesirable variability in the suspension and/or in the collecting surface could be eliminated, and the H-2 specific net effect estimated. In this way it was possible to detect (even on the background of a large non-specific variability) significant reductions of the allogeneic collection rates (i.e. between cells which differed only in their H-2 haplotypes) as compared to the syngeneic standards. It is concluded that cells of a given H-2 haplotype have preferential adhesiveness to syngeneic cells.


A human subject with a new defect in repair of ultraviolet damage.

The subject under study (11961) is a child with extreme sun sensitivity. Fibroblasts derived from the child's skin, like those from patients with the disorder xeroderma pigmentosum were hypersensitive to the lethal effects of 254 nm and 310 nm UV-irradiation. Unlike xeroderma pigmentosum cells, however, fibroblasts from our subject were not hypersensitive to the chemical mutagen N-hydroxyacetylaminofluorene but they were hypersensitive to ethylmethanesulfonate. Furthermore, despite the ultra violet light sensitivity, no defects could be detected either in excision or postreplication repair of damaged DNA after UV-irradiation of 11961 cells. This again contrasts with xeroderma pigmentosum cells, which are defective in one or the other of these repair processes. On the basis of these characteristics and the clinical symptoms, we are not at present able to classify this patient as having any of the known sun-sensitive syndromes.


Simple screening test for estimation of some phenolic and indolic compounds in urine application to melanoma.

A simple screening test for estimation of some phenolic and indolic compounds in urine is described. The method is rapid, simple and able to detect all the indolic and phenolic compounds observed, including o-dihydroxy compounds. The method is based on the color reaction with reagent solution composed of sodium tungstate, trichloroacetic acid, hydrochloric acid and sodium nitrite. After alkalinization by sodium hydroxide the optical density is measured at 405 and 490 nm. The latter is specific for o-dihydroxy compounds. This test seems to be useful for estimation of phenolic and indolic compounds in urine of patients with increased production of compounds of this nature, particularly in some tumors.


Linoleic acid effects on epidermal DNA synthesis and cutaneous prostaglandin levels in essential fatty acid deficiency.

An essential fatty acid (EFA) deficient state has been induced in hairless mice. The epidermal changes included hyperkeratosis, hypergranulosis and acanthosis. Epidermal DNA synthesis was increased 3-fold compared with normal diet mice. Prostaglandin E (PGE) and prostaglandin F (PGF) levels, measured by radioimmunoassay, were much reduced in the EFA deficient mice skin. 10% Linoleic acid applied topically for 2 weeks corrected the gross and histological skin abnormalities and reduced epidermal DNA synthesis to normal values. The levels of PGE and PGF were only partially corrected. Linoleic acid applied to normal diet mice increased skin levels of PGE and PGF compared with the control vehicle treated normal diet mice. These results provide further evidence for the importance of essential fatty acids in the control of epidermal proliferation and differentiation. The importance of PGE and PGF in controlling epidermal DNA synthesis in EFA deficiency is less clear.


Circumscribed sebaceous gland hyperplasia: autoradiographic and histoplanimetric studies.

Circumscribed sebaceous gland hyperplasia (sebaceous hyperplasia) is a common benign facial tumor found in adults and aged. Seventeen biopsies of sebaceous hyperplasia from 10 patients, females and males aged 57-87 years were secured which were injected 45 min or up to 15 days prior with tritiated thymidine, and prepared for autoradiography. Specimens were evaluated by cell counts (labeling index, labeled total cells), and histoplanimetric techniques (sagittal section areas and circumference of sebaceous hyperplasia, of sebocytes, and of sebocyte nuclei). Controls were uninvolved sebaceous follicles from the same subjects, from an age-matched group, and from young male adults. In sebaceous hyperplasia the labeling index of basal cells is low with 5.7% +/- 2.3 vs uninvolved sebaceous follicles from the same subject (8.6% +/- 2.4) and the younger subjects with a value of 10.1% +/- 2.0). Labeled cells are retained in the acini much longer than in young adults (slowed down transit and turnover time). The glands of sebaceous hyperplasia are very large, their sebocytes are small, and many more basal cells are found per unit basement membrane length.


Cockayne's syndrome fibroblasts have increased sensitivity to ultraviolet light but normal rates of unscheduled DNA synthesis.

Cockayne's syndrome is a form of cachectic dwarfism characterized by acute sun sensitivity and numerous other abnormalities of many organ systems. We studied fibroblasts from 9 Cockayne's syndrome patients to determine if their fibroblasts had abnormal post-ultraviolet light colony-forming ability or abnormal ultraviolet light-induced unscheduled DNA synthesis. The fibroblast strains from all the patients had markedly decreased post-ultraviolet light colony-forming ability in comparison with fibroblasts from control donors. Since this increased ultraviolet light sensitivity is propagable in vitro, it may be a manifestation of, or be closely associated with, the inherited genetic defect of this autosomal recessive disease. However, the patients' fibroblasts had normal rates of ultraviolet light-induced unscheduled DNA synthesis. Thus, unlike the UV sensitivity of DNA excision repair-deficient xeroderma pigmentosum strains, the UV sensitivity of Cockayne's syndrome strains is not related to abnormal DNA excision repair, at least to the extent that this repair process is reflected by rates of ultraviolet light-induced unscheduled DNA synthesis.


DNA synthesis among uninvolved and involved psoriatic epidermal cells and normal epidermal cells in vitro.

Epidermal cells from 8 patients with psoriasis (involved and uninvolved areas) and from 7 normal individuals, were propagated in vitro. DNA synthesis was determined autoradiographically by measuring the labeling index (1 hr) and a continuous labeling index (72 hr) on 8-10 day old cell cultures. No differences in these 2 kinetic parameters were obtained with respect to involved and uninvolved psoriatic cells. However, when psoriatic cells (involved and uninvolved) were compared to normal cells, the psoriatic cells exhibited a much higher labeling index and continuous labeling index, 200-300% and 60-70% respectively. These data clearly show that in vitro (1) epidermal cells from clinically uninvolved skin of psoriatics proliferate at a rate equal to that of involved psoriatic cells and (2) psoriatic epidermal cells proliferate at a rate greater than normal cells.


Identification of systemic phototoxic drugs by human intradermal assay.

An improved method is presented for the detection of systemically administered photosensitizing drugs in humans. Test agents were injected intradermally in physiologic saline and then exposed to broad spectrum radiation from a Xenon solar simulator. Several clinically recognized photosensitizers were identified by this technique. The activating spectrum depended on the test drug. Sulfonamides and vinblastin were activated by sunburning erythemic radiation (UV-B), while tetracyclines, nalidixic acid and phenothiazines by near UV (UV-A), and chlorothiazide by both. It is suggested that intradermal phototesting offers a means of verifying the phototoxic potential of agents suspected clinically of provoking a photosensitivity eruption.


Effects of 4-tertiary butyl catechol on tissue cultured melanocytes.

Depigmenting effects of 4-tertiary butyl catechol (TBC) were investigated using tissue cultured melanocytes of adult guinea pig. Black guinea pig ear epidermis was trypsinized, suspended in BME Eagle media (5 X 10(6) cells) supplemented with 10% calf serum, and seeded in Petri dishes (2 ml/ea). On the 5th day of culture, TBC dissolved in DMSO was added to the media, and the central area of Petri dishes with large numbers of melanocytes (but not keratinocytes) present were examined by light and electron microscopy. After 6 hr of treatment with 1.5 X 10(-3) mg TBC per ml of media, about 15 to 30% of melanocytes detached and about half of the remaining cells showed reversible changes in the cell shapes. An increase of TBC concentration to more than 2 X 10(-3) mg per ml of media resulted in larger numbers of melanocyte deaths. The surviving cells contained numerous, but ultrastructurally unusual premelanosomes and melanosomes. In addition, microfilaments showed a wavy appearance.


Counting and sizing of epidermal cells in normal human skin.

During keratinocyte maturation, individual cells undergo an orderly succession of biochemical and structural changes. In certain skin disorders alterations in keratinocyte numbers, volumes, and epidermal skin thickness occur. To assess such alterations and to provide base line values for normal human epidermis, a computer assisted histologic technique was developed. Skin biopsies were taken from normal skin on the forearm, back and thigh of 6 adult men. Whole specimens of epidermis were separated from the dermis with collagenase, fixed, stained, and mounted for microscopic examination. From the three dimensional coordinates of epidermal nuclei, epidermal cell volumes, surface density of epidermal cells, and epidermal thickness were determined. Measurement of cell volumes in this way compared favorably with electronic cell sizing of disaggregated epidermal cells in matched samples. The mean densities of nucleated cells per 10(4) mu2 surface area were 452, 483, and 487 for the forearm, back and thigh respectively. This technique will be used to make similar assessments in disorders of abnormal keratinocyte maturation.


The keratin polypeptides of psoriatic epidermis.

The polyacrylamide SDS electrophoretic pattern of protein extracted from the stratum corneum obtained by scraping the surface of involved skin of patients with psoriasis was different from that of uninvolved skin and normal controls. The pattern from superficial scales was similar to that of whole stratum corneum in the case of involved psoriatic epidermis but different in uninvolved and normal epidermis. These data indicate that the changes which are observed in the structural proteins during normal keratinization are not seen in involved psoriatic epidermis. In addition, the relative proportion of keratin polypeptides was different in involved psoriatic epidermis compared to normal skin. That these changes are not specific for psoriasis was shown by finding similar electrophoretic patterns with stratum corneum proteins from patients with other keratinizing disorders.


The effects of ancrod, the coagulating enzyme from the venom of Malayan pit viper (A. rhodostoma) on prothrombin and fibrinogen metabolism and fibrinopeptide A release in man.

The action of ancrod on fibrinogen and prothrombin metabolism was studied in six healthy individuals by the use of 131I-fibrinogen and 125I-prothrombin and by measurement of blood levels of fibrinopeptide A. Two untreated healthy controls were studied at the same time. Rapid defibrinogenation occurred during the initial 3 hr ancrod infusion, and fibrinogen levels were maintained near zero throughout the study. Large quantities of non-thrombin-clottable TCA-precipitable 131I material could be demonstrated in the circulation, reaching a maximum 3 to 6 hr after ancrod infusion and clearing with a half-life of 6 hr. Gel filtration of 6 hr plasmas demonstrated the presence of complexes larger than fibrinogen, as well as degradation products of fibrinogen-fibrin. Prothrombin concentration and metabolism were unchanged by ancrod treatment. Fibrinopeptide A levels in the ancrod group were greather than 4,000 ng/ml during the initial defibrinogenation, declined to greater than 80 ng/ml, and then increased to high levels after 3 days. These studies provide explanations of previous observations concerning the specificity of ancrod and demonstrate that rapid clotting of fibrinogen and dissolution of fibrin can occur in vivo without recruitment of the classic coagulation mechanism.


Effects of Aureomycin on bile acids in rats.

Primary BA's secreted into the duodenum are extensively altered by bacteria in the large intestine. Such changes are not found in GF animals. As a result, GF rats reabsorb BA much more efficiently than do CV controls, and BA and cholesterol pools are higher in GF than CV rats. This indicates the importance of the intestinal flora in the homeostasis of cholesterol metabolism. Antibiotics can affect the extent to which BA's are altered by bacteria. In some cases, the antibiotic treatment also affects cholesterol levels in serum or liver. We have found that treatment of CV rats for only 5 days with low levels of Aureomycin (0.85 micron) led to a predominance of omega-MC over HDC in the feces at 10 days after withdrawal of the antibiotic. This reduced the usual HDC/omega-MC ratio from approximately 2.0 to 0.9 or less. These rats were also found to have liver cholesterol levels modestly elevated over those of controls. In other experiments the decrease in hyodeoxycholate/omega-muricholate ratio was found to persist for at least 90 days after discontinuation of treatment. Later experiments carried out with Aureomycin and with penicillin revealed the possible existence of a resistance factor to Aureomycin. A significant lowering of the hyodeoxycholate/omega-muricholate ratio was now found only with antibiotic concentrations 10 to 100 times greater than those used previously. Possible implications of the persistence of antibiotic effects, as measured by changes in fecal BA's, include effects on vitamin metabolism, colon cancer, and cholesterol metabolism.


Relative hemostatic effectiveness of human platelets stored at 4 degrees and 22 degrees C.

Platelet concentrates stored at 2 degrees to 4 degrees C or at 20 degrees to 24 degrees C for 24 or 72 hr were transfused to 22 thrombocytopenic patients selected to minimize host factors which affect the survival and function of transfused platelets. Platelets stored at either temperature range for only 24 hr were equally effective in elevating platelet levels and in shortening bleeding times, 1, 4 and 24 hr after transfusion. After 72 hr of storage, however, refrigerated platelets were significantly less effective than platelets kept at room temperature by these two criteria. We suggest that routine storage of platelets at 2 degrees to 4 degrees C can no longer be justified except possibly when platelets are to be shipped over long distance by common carrier and transfused within 24 hr of preparation.


Renal sodium conservation during starvation in the rat.

The phenomenon of natriuresis during the early phase of total starvation has been described in man and rabbit. We have examined the pattern of electrolyte excretion initiated by starvation for 4 days in the male Wistar rat. Within 24 hr sodium excretion is significantly diminished when compared to prestarvation values (control 2.55 +/- 0.76 [S.D.] mEq/day; 1-day fast 0.42 +/- 0.27) and by day 2 is less than one tenth of the control value. Chloride retention parallels this sodium conservation. Concomitant changes in urinary pH and ammonia excretion (UNH4V) reflect the mild acidosis of starvation (control pH 7.46 +/- 0.18 [S.D.], UNH4V 0.21 +/- 0.08 [S.D.] mEq/day; day 2 pH 6.10 +/- 0.31, UNH4V 0.71 +/- 0.21). However, the excretion of organic acids is not elevated but is actually decreased by day 2 (control 1.02 +/- 0.21 [S.D.] mEq/day; day 2 0.66 +/- 0.26). The majority of the organic acids are excreted as salts (day-2 0.51 +/- 0.21). This level of excretion does not obligate excessive sodium loss and can be adequately matched by renal ammonia production. Normal plasma glucose levels are maintained, consistent with the well-documented increase in renal gluconeogenesis in the starved rat. Plasma levels of glucagon, a known natriuretic and ketogenic agent, do not rise, and this together with a normal plasma glucose concentration may account for the failure of the rat to exhibit the natriuresis of starvation that is observed in man and rabbit.


HgCl2-induced acute renal failure in the Goldblatt rat.

These experiments were designed to test the hypothesis that renal renin is an important determinant of the severity of acute renal failure in rats. Two-kidney "Goldblatt rats" were prepared by constricting the left renal arteries with silver clips and leaving the contralateral arteries untouched. After 2 to 5 weeks, the clips were removed, and HgCl2 was injected in 13 rats (1 ml/kg body weight of 4.7 mg of HgCl2 per milliliter of 140 mM NaCl). These rats exhibited the characteristic features of acute renal failure 24 hr later. As compared with a group of seven similarly treated rats injected with 140 mM NaCl without HgCl2, GFR, V, and UNaV were reduced, and %FE H2O and %FE Na were increased. As assessed by these parameters, severity of functional impairment was equal in both kidneys. However, cortical renin was 28 times higher in the left kidney than in the right. These results are inconsistent with the hypothesis.


Survival of normal and magnesium-deficient erythrocytes in rats: effect of magnesium-deficient diet vs. splenectomy.

Magnesium deficiency in rats causes anemia, the mechanism of which is unknown. The effect of dietary magnesium, splenectomy, and magnesium content of erythrocytes on erythrocyte survival was studied in Fisher rats. Half of the animals were splenectomized, the remainder sham-splenectomized; each group was subdivided, and some were placed on a magnesium-deficient diet, the rest on a control diet. After 6 weeks, each of the four subgroups was divided, half were given 51Cr-labeled red cells from magnesium-deficient rats, the remainder, labeled normal red cells. The survival functions of the labeled erythrocytes were fitted to a mathematical model composed of both first-order and accelerating components. The results show that the most important factor influencing erythrocyte survival was dietary magnesium intake. The magnesium content of the transfused red cells affected erythrocyte survival only in the rats fed the control diet, whereas splenectomy affected erythrocyte survival only in rats receiving the magnesium-deficient diet. The accelerating component of the survival function was increased eightfold in the animals fed the magnesium-deficient diet, whereas much smaller changes occurred in the first-order components.


Hemoperfusion removal of digoxin from dogs.

Removal of digoxin by XAD-4 hemoperfusion columns was tested after four dogs were given 0.06 mg/kg of digoxin i.v. Dogs were perfused for 4 to 5 hr at a flow of 105 ml/min through a 100 gm XAD-4 column 16 hr after the dose. Pharmacokinetic analysis of digoxin levels was performed with a three-compartment model. The apparent postdistribution t1/2 was 16.0 +/- 2.9 (S.D.) hr and decreased to 7.1 +/- 2.1 hr during perfusion. Digoxin perfusion clearance was 46 ml/min. An average of 51 microgram of digoxin was recovered from used columns. CP of digoxin calculated from the total R was 127.5 +/- 13 ml/min or 2.3 times greater than plasma flow. With the use of 3H-digoxin, canine blood was found to contain 2.5 times as much digoxin as did plasma. After perfusion there was an increase in serum digoxin levels in all dogs. Computer analysis showed that the increase in plasma digoxin levels immediately after hemoperfusion occurred because the central compartment, which was depleted of digoxin during hemoperfusion, was refilled from peripheral compartments. This study demonstrated that (1) XAD-4 hemoperfusion doubles the rate of removal of digoxin from dogs, (2) dog whole blood contains more than twice as much digoxin than does plasma, so that hemoperfusion clearance exceeds plasma flow, and (3) a multicompartmental pharmacokinetic model explains the increase in serum digoxin concentrations observed at the completion of hemoperfusion.


Measurement of serum proinsulin-like material: cross-reactivity of porcine and human proinsulin in the insulin radioimmunoassay.

The variation in cross-reactivity of human and porcine insulins and proinsulins was determined with a number of insulin antisera. The relative immunoreactivity of insulin and proinsulin with these antisera ranged from a ratio of 1.08 to 5.7 on a molar basis. The displacement curves of human insulin and proinsulin were not parallel, and the relationship of porcine and human proinsulin varied with different antisera. Sera with varying concentrations of PLM (proinsulin and its intermediate components) and serum PLM and insulin fractions (separated by gel filtration) were measured in two assays using the antisera which reacted most differently with human insulin and proinsulin standards. With the use of these two antisera, measurement of serum PLM against a human insulin standard gave different results, which were only partially corrected by reading the values from a human proinsulin standard. The magnitude of the serum IRI differences with these antisera was related to the proinsulin/insulin ratio in each sample. These results indicate the necessity for each laboratory to critically evaluate the reaction of their insulin antiserum with human proinsulin. In addition, measurement of serum PLM in terms of a insulin standard will give different results depending upon the particular antiserum used.


Plasma prolactin in essential and renovascular hypertension.

Plasma prolactin response to postural change and variation in dietary sodium was evaluated in five normal volunteers and 15 patients with essential hypertension. Values at 0800 hours (11.9 +/- 3.5 ng/ml, mean +/- 1 S.D.) were uninfluenced by the duration of recumbency (10 or 34 hr) and were significantly higher than those obtained at noon (6.9 +/- 3.5 ng/ml, mean +/- 1 S.D., p less than 0.001). The latter were uninfluenced by postural change. There was no correlation between sodium intake and plasma prolactin, nor was there any apparent correlation between prolactin and plasma renin activity. There was no significant difference in prolactin concentrations between normotensive and hypertensive subjects. In 10 additional patients with unilateral renal disease, renal vein prolactin concentrations did not differ significantly from simultaneously obtained peripheral concentrations. Renal vein prolactin was uninfluenced by the presence of renal disease and did not correlate with renal blood flow. It is concluded that there is no evidence of feedback between sodium intake and prolactin in man. Human kidneys do not seem to clear significant amounts of prolactin. It appears unlikely that alterations in prolactin concentration, at least as assessed by daytime values, participate in the maintenance of either essential or renovascular hypertension. Since values at 0800 hours are frequently elevated as a reflection of preceding sleep-related peaks, sampling at 1200 hours may be preferable when search is undertaken for hypothalamic-pituitary disease.


Diaphragmatic EMG response to isocapnic hypoxia and hyperoxic hypercapnia in humans.

The EMGdi response to both isocapnic hypoxia and hyperoxic hypercapnia was studied in the same sitting in six normal subjects. Rebreathing methods achieving "open loop" conditions were used. EMGdi was quantified as a moving time average. In almost all subjects, during hypoxia changes in EMGdi were inversely and hyperbolically related to changes in PAO2. When EMGdi was plotted against extrapolated O2 saturation, the relationship was linear in all subjects. The EMGdi response to hypoxia was qualitatively similar to the concurrent responses VI and P.15. EMGdi was linearly related to PACO2 during CO2 rebreathing. The slopes of the EMGdi response to decreasing O2 saturation were positively correlated to the slopes of the EMGdi response to PACO2, so that subjects with a low hypoxic response also had a low CO2 response and vice versa. The couplings of neural to muscular and muscular to ventilatory events as assessed by the ratio of the slopes of EMGdi to P.15 and P.15 to VI, respectively, were similar for all subjects and were not related to the degree or type of chemostimulation. The following were our conclusions. (1) EMGdi can be used as an index of respiratory motoneuron drive during hypoxic or hypercapnic breathing in normal humans. (2) The relative degree of responsiveness to hypoxic and hypercapnia stimuli (chemosensitivity) appears to be similar in any given individual. (3) In normal subjects, changes in inspiratory muscle pressure and ventilation are proportionate to changes in inspiratory neural drive as assessed by EMGdi.


The influence of plasma bilirubin on zinc protoporphyrin measurement by a hematofluorimeter.

A fluorimeter has recently been developed to detect lead poisoning and iron deficiency by measuring erythrocyte ZPP directly from whole blood. Plasma bilirubin fluorescence has been found to influence this technique. ZPP levels determined by the fluorimeter were elevated by artificially increasing the plasma bilirubin concentration, both within and above the normal range, in whole blood samples. A rise in ZPP levels were also observed when the hemoglobin concentration was lowered by dilution with native plasma. When blood samples of patients with hyperbilirubinemia were analyzed, direct measurement of ZPP by this fluorimeter yielded significantly higher levels than did an alternate extraction method. Photodegradation of bilirubin in whole blood samples did not decrease fluorescent interference. Although the bilirubin measurably decreased, fluorescence increased following a 5 hr exposure to light.


A sensitive radioimmunoassay method for urinary kinins in man.

A sensitive and specific radioimmunoassay method for urinary kinins was developed, which uses antiserum against synthetic bradykinin in combination with labeled tyr8-bradykinin. The assay detects as little as 6 pg per tube of bradykinin. The dose-response curves of bradykinin. lysyl-bradykinin (kallidin), and methionyl-lysyl-bradykinin were almost identical. This suggests that the values estimated with bradykinin as the standard exhibit the total urinary kinins which contain these three peptides. The assay was performed without extraction of urinary samples, since a chromatographic study demonstrated that no interfering substances in urine samples remain in our assay system. The urinary levels of total kinins in 10 normal male subjects, three male patients with chronic renal failure, and 12 male patients with essential hypertension was 37.9 +/- 3.9 microgram/day (mean +/- S.E.M.), 9.0 +/- 5.1 microgram/day, and 24.2 +/- 5.2 microgram/day, respectively.


Fibronectin concentration is decreased in plasma of severely ill patients with disseminated intravascular coagulation.

Plasma fibronectin (cold-insoluble globulin) is known to be cross-linked to fibrin during the final stage of blood coagulation and is probably the major nonspecific opsonin of blood. We measured the concentration of plasma fibronectin in 36 hospitalized patients (11 with malignancy, 12 with infection, 13 with other underlying diseases) with evidence of fibrin depostion and lysis. Plasma fibronectin concentration was greater than 2 S.D. below the mean of normals in 17 of the patients (p less than 0.001). Depression of fibronectin was not related to severity of disseminated intravascular coagulation, as assessed by fibrinogen concentration and the quantity of FDP in serum. Depressed plasma fibronectin concentration and the quantity of FDP in serum. Depressed plasma fibronectin concentration was an unfavorable prognostic finding, inasmuch as 12 of the 17 patients with depressed fibronectin concentrations died during hospitalization as compared to five of the 19 patients with normal fibronectin concentrations (p less than 0.02). We speculate that specific depletion of plasma fibronectin, because of codeposition with fibrin or due to increased utilization as a nonspecific opsonin, may contribute to the organ failure seen in severely ill patients.


Role of the spleen and lymphocytes in regulation of the circulating platelet number in mice.

The role of the spleen in the regulation of the circulating platelet number was studied in mice. The increased 75Se-Met incorporation found after removal of the spleen indicates that postsplenectomy thrombocytosis is due to enhanced platelet production. The increased thrombopoietic activity observed in the plasma of splenectomized mice proves the presence of a humoral factor which mediates this process. Administration of spleen lymphocytes to control mice caused mild thrombocytopenia and prevented postsplenectomy thrombocytosis in splenectomized animals. Moreover, culture medium obtained from peripheral blood and spleen lymphocytes contained a substance which induces thrombocytopenia when injected into control mice. The mechanism by which the spleen and lymphocytes affect the amount of circulating platelets is discussed.


Importance of the isolation of 25-hydroxyvitamin D before assay.

A protein-binding assay for determination of 25(OH)D was used to analyze the profile of chromatographed ethanol extracts of serum. There were substances in the serum of normal subjects which displaced labeled 25(OH)D3 from the binding protein and which were different from 25(OH)D or 24R,25(OH)2D. Values of 25(OH)D from serum samples without prior chromatography were higher than those obtained with chromatography (40.2 +/- 12.2 ng/ml vs. 22.3 +/- 8.2, mean +/- S.D.). This indicates a need for chromatography before assay to ensure specificity of 25(OH)D measurement.


Connective tissue activation. XIII. Stimulation of sulfated glycosaminoglycan synthesis in human connective tissue cells by peptide mediators from lymphocytes and platelets.

CTAP-I from lymphocytes and CTAP-III from platelets markedly stimulated 35SO4= incorporation into chondroitin 4/6 sulfate and dermatan sulfate synthesized by human synovial, dermal, and cartilage connective tissue cells in vitro. These agonists promoted synthesis of the GAG carbon chain as well as sulfate incorporation. Both RNA and protein synthesis were required for these mediators to be effective in stimulating synthesis of connective tissue matrix components. A major part of the capacity of normal serum to stimulate sulfate incorporation into GAG's may reside in CTAP-III.


Effect of phagocytosis and Fc receptor occupancy on complement-dependent neutrophil chemotaxis.

Neutrophil migration was assessed following cell interaction with IgG or after phagocytosis of antibody-coated EA or latex. The migration of these neutrophil preparations was markedly impaired as studied in an agarose medium with ZAS as the chemoattractant. Neutrophils which had interacted with EA retained some capacity for directed migration toward synthetic tripeptides and E. coli filtrate. Rosette formation with EA(IgM)C3 did not impair cell movement. The reduced cell migration observed after immune or nonimmune ingestion was reversible following a prolonged incubation period. The results suggest that phagocytosis or Fc receptor occupancy transiently blocks the ability of neutrophils to migrate.


Acromegaly and the temporal bone.

Acromegaly is a chronic disease of middle life resulting from excessive secretion of growth hormones by the acidophil cells of the anterior pituitary. The typical clinical features include enlargement of the skull, thorax, hands and feet. Recently, three patients with acromegaly have been operated upon for active otologic disease. In spite of massive mastoid cortex bone, the structures of the otic capsule were found to be of normal dimensions and in the usual relationships.


Simultaneous histological, audiological and radiological findings in congenital anomalies of the inner ear.

Twenty-eight cases of children with deafness or severe perceptive impairment of hearing are discussed. They are selected into two groups for the symmetrical longitudinal planigraphy of the ear, the findings of which enable us to prove a labyrinthine aplasia and to compare them with audiometric findings. Accordingly we are able to draw a definite conclusion in small children. Histological findings about congenital anomalies of the inner ear with changes in the cochlea may also be divided into two groups: 1. Complete absence of development of inner ear with labyrinth aplasia. 2. Greater or lesser aplasia in the bony part of the cochlea Subgroups: (a) classic type after Mondini; (b) partial type after Mondini.


The post-auricular myogenic response: a new instrument which simplifies its detection by machine scoring.

A portable apparatus is described which can be used for routine audiometric screening in a children's clinic. The apparatus measures the postauricular myogenic response to click stimuli and the design of the machine makes for great simplicity of operation. A simple form of machine scoring is employed so that a completely objective result is obtained. Evaluating the equipment on 102 subjects produced no false positive results, but a small percentage of normally hearing adults and children failed to produce a response. The equipment was successfully evaluated in a routine audiometric screening situation on 46 babies aged 6 to 9 months.


Difficulties in management of vocal cord precancerous lesions.

Hyperplastic aberrations are differently classified and the term of precancerosis diversely interpreted; therefore, it is extremely difficult to evaluate the effectiveness of particular therapeutic methods. A standardized classication would enable an objective assessment of the treatment for precanceroses. Our own conception of the histologic patterns in precanceroses is presented. In the period 1960-1975, a total of 2,700 biopsies were performed in patients with hyperplastic aberrations in the vocal cord mucosa. In 133 patients, histology revealed precancerosis. In the patients who had received medical therapy, no improvement was obtained; on the contrary, in 16 patients the process became malignant. Among the patients who had undergone de-epithelialization (61), 44 were cured. After the de-epithelialization, no precancerous case turned malignant. De-epithelialization has been shown to be the procedure of choice for the treatment of precanceroses of the vocal cord.


Guillotine tonsillectomy: anachronism or pragmatism.

The results of a retrospective survey comparing the complications of guillotine tonsillectomy with those of dissection tonsillectomy are given. The problem of tonsil tags and adenoidectomy are discussed and a reappraisal of the indications for guillotine tonsillectomy are considered. We feel that guillotine tonsillectomy should only be carried out in very special circumstances.


A new approach to the treatment of laryngeal papilloma in adults.

Twenty-six cases of multiple laryngeal papillomatosis were treated by a newly developed grafting technique. The larynx was opened in the midline under local anaesthesia and the tumour mass was surgically resected. Mucous membrane along with the lamina propria was taken from patient's upper jaw and grafted over the wound, with the help of plain catgut on an atraumatic needle. Although our patients have been observed for only a short period of 5 years from 1972, no recurrence has been seen and good vocal cord function has remained.


Leiomyosarcoma of paranasal sinuses.

A leiomyosarcoma of the upper respiratory and food passages is a rarity. Two rare cases of leiomyosarcoma of the paranasal sinuses, of which one developed recurrence are reported.


Cutaneous horn.

Cutaneous horn or sebaceous horn is an extremely rare clinical entity. A case of cutaneous horn of the cheek presenting in a middle aged female is reported. It was successfully treated by surgical excision.


Effect of perinatal oestrogen on the pretreatment required for mouse mammary lobular formation in vitro.

Morphological differentiation was enhanced in mammary glands from mice injected with oestradiol as neonates both in vivo, after 9 days of pretreatment with oestrogen and progesterone, and in vitro, either after 6 or 9 days of pretreatment and on all hormone supplements, or after culture with oestradiol, progesterone, aldosterone, insulin and thyroxine with or without prolactin and growth hormone. These hormone combinations further enhanced development, whereas culture with insulin and thyroxine did not. Differentiation in vitro was least on medium containing insulin + thyroxine, and was greatest on the complete medium (insulin, thyroxine, growth hormone, prolactin, aldosterone, progesterone and oestradiol). An intermediate degree of differentiation occurred when growth hormone and prolactin were omitted from the complete medium. Differences in lobule formation between oestrogen-treated and control mice were probably ovary-dependent at the dose used (25 microgram/day), since pretreatment with oestradiol and progesterone was necessary to reveal them. Enhanced hormone sensitivity of murine mammary tissues exposed to oestradiol early in life may be related to subsequent enhanced dysplastic potential of the tissue and provides a further basis for caution in the administration of steroids to immature individuals.


Investigations into the role of calcium ions in the control of steroid production by isolated adrenal zona glomerulosa cells of the rat.

An increase in the concentration of extracellular potassium from 3.6 to 8.4 mmol/1 had only a small delayed effect on the uptake of radioactive calcium by isolated adrenal glomerulosa cells. However, the same stimulus had a rapid and highly significant effect on the efflux of radioactive calcium from glomerulosa cells preloaded with 45Ca2+. Cells incubated in medium containing 8.4 mmol potassium/1 had retained approximately 15% more radioactivity than conrol cells after 2.5 min and this difference was maintained for up to 90 min. There was an increase in the production of steroids by the glomerulosa cells in the presence of 8.4 mM-potassium. No effect on calcium efflux was observed in similar experiments with isolated fasciculata cells; it has been established that this concentration of potassium does not affect steroidogenesis in fasciculata cells, indicating that the effect on glomerulosa cells may be causally linked to steroidogenesis. There was no significant change in the total calcium content of glomerulosa cells in the presence of 8.4 mM-potassium. Exchangeable calcium in these cells was found to be 60% of the total calcium content.


DNA synthesis and depletion of prolactin in the pituitary gland of the male rat.

Haloperidol, bromocriptine and diethylstilboestrol dipropionate were given in various régimes to male rats to determine their effects on pituitary DNA synthesis, prolactin secretion and growth hormone secretion. Haloperidol increased serum prolactin but did not stimulate pituitary DNA synthesis or reduce pituitary prolactin concentrations. Haloperidol potentiated the effects of oestrogen on serum prolactin and on pituitary DNA synthesis; pituitary prolactin concentrations were greatly reduced, and growth hormone secretion was slightly inhibited. The inhibitory effects of bromocriptine in oestrogen-stimulated rats were demonstrated by smaller pituitary weights and decreased DNA synthesis; serum prolactin levels were lowered and pituitary prolactin concentrations were increased. Haloperidol, given to rats treated with oestrogen and bromocriptine, reversed the inhibitory effects of bromocriptine on DNA synthesis and serum prolactin; pituitary prolactin concentrations fell to well below normal. The results suggest that the haloperidol potentiation of oestrogen-induced pituitary DNA synthesis may depend upon stimulation of prolactin secretion together with reduction of intracellular prolactin levels.


Effects of ovarian steroids and prolactin on the contractility and sodium pump site density of guinea-pig myometrium.

Ovariectomized guinea-pigs were given a single dose of oestrogen or progestogen or the two steroids combined. Controls were given 0.9% saline. Four days after the injection, myometrial contractility in response to spasmogens was measured isometrically in isolated tissue baths, both before and after incubation in Kreb's solution with or without added prolactin. Further myometrial strips were also incubated with or without prolactin and the density of Na+/K+ ATPase 'pump' sites on the surface of the myometrial cell was estimated by labelling with tritiated ouabain. Incubation with prolactin significantly reduced the contractility of myometrial tissue from guinea-pigs given saline alone, progestogen alone or progestogen plus oestrogen, but not in tissue from animals pretreated with oestrogen. When myometrial strips from animals pretreated with oestrogen or progestogen were incubated without prolactin in the medium, there was a significant increase in the density of pump sites compared with the number in saline-pretreated animals; incubation with prolactin did not further modify this effect. When both steroids were administered together there was a significant increase only when prolactin was present in the incubation medium. There was also a significant increase in the density of pump sites after incubation of myometrium from the control (saline-pretreated) animals in the presence of prolactin.


Feedback control of follicle-stimulating hormone in pre-and postpubertal rams as revealed by hemicastration.

The levels of FSH, LH and testosterone in the plasma were measured in cross-bred male lambs which were bilaterally castrated, hemicastrated or left entire at 1 week of age. Removal of one testis caused the level of FSH in the circulation to increase to a value midway between the levels found in entire and castrated lambs up to 12 weeks of age. The concentrations of LH and testosterone in the plasma were similar in the control and hemicastrated lambs. The concentration of FSH in the plasma of the hemicastrated lambs fell at 12--14 weeks of age, the expected time of puberty, to the level found in control animals of the same age. Although the possibility of increased release of LH cannot be excluded, the increase in the secretion of FSH is believed to account for the compensatory hypertrophy of the remaining testis observed in the hemicastrated lambs. Removal of one testis from mature Soay rams in sping (May) caused a small selective increase in the concentration of RSH in the plasma, compared with entire animals. This difference was maintained until July when there was a marked increase in the levels of FSH and LH in the hemicastrated rams such that an exaggeration of the normal seasonal changes in these hormones was observed. Compensatory hypertrophy of the remaining testis was observed in the hemicastrated animals.


Histoenzymological studies of 3beta- and 17beta-hydroxysteroid dehydrogenases in the placentae and adrenal glands of bilaterally ovariectomized rats.

The distribution and activities of 5-unsaturated-3beta- and 17beta-hydroxysteroid dehydrogenases (HSD) have been studied during the pregnancy of normal and ovariectomized rats on days 17, 19 and 21 post coitum. No hormonal substitution was provided after bilateral ovariectomy on day 15 post-coitum. 5-Unsaturated-3beta-HSD was characterized with pregnenolone, 17alpha-hydroxypregnenolone and dehydroepiandrosterone as substrates; oestradiol-17beta and testosterone were used for the investigation of 17beta-HSD activity. With these substrates, it was found that the placental and adrenal activities and distribution of 5-unsaturated-3beta- and 17beta-HSD did not differ in ovariectomized and control rats and it is suggested that increased placental or adrenal steroidogenesis does not supplement deficient ovarian function in order to maintain pregnancy. In the pregnant rat, the ovaries do not control the activities of 5-unsaturated-3beta- and 17beta-HSD in the placenta.


An evaluation of the Jeol Clinalyzer.

The Jeol Clinalyzer was evaluated over a period of 15 weeks. The operating principles are briefly described. The functions of the mechanical components were tested and assessments made of the instrument's safety and reliability. The mechanical and electrical reliability of the instrument was excellent and the pumps and spectrophotometer gave good accuracy and precision. Between-batch precision of the analytical methods was good for urea, protein and bilirubin and acceptable for alkaline phosphatase and aspartate transaminase. There was a poor relative accuracy for alkaline phosphatase and aspartate transaminase and some proportional inaccuracy for urea and bilirubin.


Influence of monoethanolamine on activity measurements of the isoenzymes of alkaline phosphatase.

Monethanolamine, a frequent impurity of diethanolamine, inhibits the activity of the isoenzymes of alkaline phosphatase to various extents. Isoenzymes from liver and bone, in particular, are strongly inhibited. Inhibition is stronger at lower (25 degrees C) than at higher temperatures (37 degrees C).


[Microdetermination of glucose using glucose dehydrogenase, with independent sample preparation in the routine laboratory (author's transl)].

A micromethod for the determination of glucose in 20 microliter of capillary blood using glucose dehydrogenase is described. After deproteinisation with uranyl acetate, the samples are analysed by an Autoanalyzer II method or by a manual procedure. Precision and accuracy are well correlated with the hexokinase-glucose-6-phosphate dehydrogenase method. Eleven months experience have shown the practicability and economic advantages of this method.


[The determination of capillary blood glucose using the automatic clinical analyzer (aca) Dupont (author's transl)].

The determination of capillary blood glucose after deproteinization using the aca is described. The method, which uses the hexokinase/glucose-6-phosphate dehydrogenase reaction, is compared with the glucose dehydrogenase method. The comparison shows that glucose values measured in capillary blood are essentially the same in both methods. The requirements for quality control are fulfilled. The method is not influenced by hemolysis, bilirubinemia, and hypertriglyceridemia.


[Kinetic assay of creatinine with the Gemsaec-Fast-Analyzer; comparison with the Fuller's earth method (author's transl].

A kinetic method is described for the determination of creatinine in serum. The method is adapted for use with Gemsaec-Fast-Analyzer. The reliability criteria of the method are reported. The only interfering substance is bilirubin, which, when present in elevated concentrations, causes an apparent decrease in the level of creatinine. This interference can be avoided by treating the sample with Fuller's earth prior to the creatinine determination. 72 sera were analysed by the kinetic method and by the Fuller's earth method without deproteinization (5). There was excellent agreement between the two methods (y=1.011 x--0.8222;r=0.9970).


A simple and sensitive radiochemical assay for plasma guanase.

A simple and sensitive radiochemical micro-assay has been developed for the determination of plasma guanase activity. The method is based upon the measurement of the conversion of 14C-labeled guanine to xanthine, catalysed by the enzyme guanase (guanine aminohydrolase;EC 3.5.4.3). Using this method, the catalytic activity in the plasma of adult healthy controls was 0.040 +/- 0.09 nmol/h.mg protein (x +/- s). In children under 5 years of age higher levels of enzyme activity were demonstrated. In adult patients with liver disease plasma guanase activities were found to be 3 to 7-fold increased as compared to the normal adult mean value.


[The importance of ionic strength and protein concentration in the dialysis performance of autoanalyzer systems for the enzymatic determination of uric acid (author's transl)].

An earlier method for the determination of uric acid (this journal 13, 89--96, (1975) was reevaluated. It was confirmed that it is necessary to add NaCl and a detergent to the wash fluid in order to obtain full sensitivity and linearity. Protein components in the samples or in secondary standard solutions also increase sensitivity and straighten the calibration curve of primary standard solutions. The effects are compared with results reported in the literature, and the possible mechanisms of these effects are discussed.


[Interference by glutathione reductase in the "CK-MB-inhibition-test": elimination of the catalytic activity of glutathione reductase by anti-glutathione reductase (author's transl)].

Glutathione reductase interferes in the determiniation of creatine kinase-MB by the "CK-MB-inhibition-test". In 36 out of 55 serum samples with normal and elevated catalytic activities of creatine kinase, "negative" values greater than 14 U/l were obtained for the creatine kinase-MB. This interference by glutathione reductase is avoided by preincubation of the serum samples for 5 min with anti-glutathione reductase.


[Adaptation of the SMAC for the determination of uric acid with an uricase/perioxidase procedure (author's transl)].

We describe the enzymatic determination of uric acid (uricase/peroxidase) with the SMAC system. The method correlates well with known SMA 12 and Autoanalyzer methods. The change from the original uric acid method to the enzymatic one is simple and does not require any change of the software.


Cystic fibrosis: making a correct and early diagnosis.

Cystic fibrosis is detected with increasing frequency in older children, adolescents, and even young adults. The quality of life and longevity in patients with cystic fibrosis is more favorable the earlier a diagnosis is made and a therapeutic regimen begun. This report presents and reviews five cases in chich the diagnosis of cystic fibrosis was made after the age of six years. Emphasis is placed on the variability of presenting signs and symptoms and the problems that can arise in confirming a suspected diagnosis of cystic fibrosis.


Treatment of obesity in family practice.

This paper describes the experience of a senior family practice resident in managing obesity using behavior modification techniques. Weight reduction was begun and continued by 9 of 32 identified obese patients. Patients who were successful in losing weight were those who kept accurate intake diaries, returned for follow-up, and had made prior attempts at weight loss. Patients who were unsuccessful in losing weight were those who kept incomplete intake diaries, had no continuing physician-patient relationship with the investigator, and had made no prior attempts at weight loss. The method management described allowed efficient use of physician time so that the time required was well within the limits set by a busy family practice setting.


Recurrent ergotism: a case report.

A patient was seen with absent pulses and vague symptoms. History and clinical findings supported a diagnosis of ergotism due to heavy use of ergotamine suppositories. The patient continued to use ergotamine despite warnings and was seen on two additional occasions with ergotism. Previously a heavy user of ergotamine, she became sensitive to small doses, demonstrating marked vasospasm after only one suppository. This phenomenon, not previously reported, is postulated secondarily to drug interaction. The patient is presented with a review of the pharmacology, toxicity, and treatment of ergotamine-induced ergotism. Alerted to the possibility of drug interactions, physicians may safely use ergotamine in the treatment of migraine headache with careful monitoring for signs and symptoms of early toxicity.


Death of an infant: parental grieving and the failure of social support.

Parents undergo intense grief reactions following the death of their newborn infant, but frequently fail to receive emotional support from their family and circle of friends. Because this response from family and friends differs from what occurs with the death of an older child or adult, this study was undertaken to explore the events and personal interactions that helped or hindered the parents following their infant's death. Alternations in familial and extrafamilial relationships are described in seven families with infant deaths, and useful support mechanisms are proposed.


Family practice in Virginia: a comparative analysis of two years' data.

Data representing Fiscal Years 1975 and 1976 as well as the aggregate 1975--1976 data set are reviewed in this paper. Information on 92,410 discrete patients and the 333,709 transactions they generated is studied. The transactions per patient rate of 3.6 varies greatly among the eight practices under investigation. This interpractice variation is complemented by remarkable year-to-year consistency within each practice. Age and the percent of continuing patients are presented as possible explanations for this variation. These data are useful to the physician in identifying the high-use patients and to the health planner for manpower and funding appropriations.


Practice profiles in evaluating the clinical experience of family medicine trainees.

A practice profile is a compilation of information allowing definition and evaluation of any of several parameters of health-care delivery. Prerequisites for development of profiles presented in this report include: suitable classification of health problems; patient demographic data; identification of individual and groups of health-care providers; and definition of the practice or study population. Details are given for two profiles: the assigned patient and the diagnostic workload profiles. Single profiles are purely descriptive but, when evaluated by appropriate peer comparison, may form the basis for a more dynamic process--that of improvement and change. Possible applications of practice profiles are discussed.


Expressed reasons for the choice of a residency in family practice.

An analysis was conducted of expressed reasons for the choice of a family practice residency by prospective residents. The nature and frequency of reasons are presented. An attempt was also made to judge the importance of saliency of specific reasons expressed. The results are discussed in relation to past studies and future directions for the training of family physicians.


A family practice residency inpatient service: a review of 631 admissions.

This study reports a review of 631 admissions by family practice residents and staff over a 12-month period to an autonomous family practice service in a large US Army medical center. The diagnoses, number and types of consultations requested, types of patients cared for by residents in various levels of taining, and other pertinent data are reviewed. The study indicates that an inpatient family practice service can be very successful in terms of physician and patient satisfaction.


Family practice residency graduates as faculty members.

The demand for teachers of family practice is being met in part by recent residency graduates. The background of these individuals would not predict that they would become teachers, and a major role adaptation is required of them. Yet a number of factors lead them to elect to become faculty members. They possess several qualities different from faculty members coming from practice backgrounds and are, therefore, able to make unique contributions. A combination of recent graduates and practice-experienced faculty members may represent the ideal mix for the further development of academic family practice.


Behavioral scientist meets the practicing physician.

The difficulty of integrating behavioral science into family practice programs is discussed by identifying (1) the problems arising from behavioral scientists, and (2) the problems arising from physicians. Some of the behavioral science issues discussed are miscommunications regarding the difficulty of understanding human behavior and empathy, and "sets" that affect diagnostic procedures and physician-patient interactions. Contributory issues, discussed which arise from physicians include the post-Flexnerian model of medical practice and the question of values in the physician role.


Limited patient knowledge as a reproductive risk factor.

A study was designed to obtain information on the concerns, attitudes, beliefs, and knowledge that women have about reproduction in order to determine how these factors affect their ability to plan pregnancies. A clinical population was studied and in general found to be uninformed and misinformed about basic physiological facts relating to reproduction. Their lack of information or their misinformation about the menstrual cycle, safe time for intercourse, and contraception contributed to unwated pregnancies. They did not know enough to prevent pregnancy. The patients were aware of some deficits in their knowledge about reproduction and expressed a desire to learn more. This study suggests that individualized education may be necessary to break the pattern of unwanted pregnancies and the feelings of apathy and fatalism so common among low-income patients.


Insomnia.

Insomnia is a symptom requiring medical investigation and the elimination of external and physical causes. Anxiety and/or depression have been shown to be present in most of the patients complaining of inability to sleep. Antidepressant medication with sedating potential is very effective in patients with depressive symptoms when most of the dose is given at bed-time. Most of the sedative-hypnotic drugs disturb the qualitative aspects of sleep and many rapidly produce tolerance. Flurazepam has been shown to be the drug of choice for purely symptomatic insomnia. Except in very transient situational stresses, a psychotherapeutic relationship to investigate the causes of the insomnia may be the most important aspect of the treatment program.


Effects of alpha-amanitin on RNA synthesis by mouse embryos in culture.

Investigations were conducted to test the effects of alpha-amanitin on RNA synthesis in preimplantation  mouse embryos. Exposure of embryos in culture to 1-100 microgram/ml alpha-amanitin produced a dose- and time-dependence suppression of total RNA synthesis as measured by incorporation of [3H]uridine. Synthesis of polyadenylated RNA in blastocyst-stage embryos was abolished by alpha-amanitin-treatment at concentrations and exposure times that suppressed total RNA synthesis by less than 15%. DNA-dependent RNA polymerase activity was measured in lysates of embryos at several stages of preimplantation development. alpha-Amanitin suppressed total polymerase activity assayed under ionic conditions favorable to the detection of RNA polymerase II. Electrophoretic analyses revealed that preincubation of blastocysts in 100 microgram/ml alpha-amanitin reduced labelling of cytoplasmic 28S and 18S RNA by inhibition of both synthesis and maturation of nucleolar 45SrRNA-precursor. This action of alpha-amanitin on nucleolar RNA synthesis cannot be correlated with the minimal suppression of nucleolar RNA polymerase activity and suggests that the synthesis and processing of rRNA may be under control of nucleoplasmic gene products.


The possible role of hemidesmosomes in neonatally estrogen-induced selection of a permanently altered abnormal vaginal epithelium.

In untreated and neonatally-estrogenized (E) Balb/c mice the numbers of hemidesmosomes per basal cell cross section (HD/bccs) gradually increases from 0.07 HD/bccs on day 1 to about 2 to 3 HD/bccs on day 4 postpartum. In untreated mice the incidence of HD's increases and plateaus at 6 to 7 HD/bccs on days 5 and 8, while during this same period in E-treated mice the incidence is increased to 14 to 15 HD/bccs. In 5-day-old E-treated mice two types of basal vaginal epithelial cells can be recognized: basophilic cells rich in HD (19.5 +/- 2.1 HD/bccs) and light cells containing only 5.3 +/- 3.3 HD/bccs. The basophilic, HD-rich cells appear to replace the lighter HD-poor cells. The hypothesis that HD's are involved in the estradiol-induced selection of an abnormal vaginal epithelium is discussed.


Nuclear protein changes in the maternally and paternally derived chromatin at fertilization.

The proteins which become associated with the paternally derived chromatin during fertilization may be instrumental in its activation and in the dramatic structural metamorphosis of the sperm nucleus during pronuclear development. Proteins associated with sperm and zygote nuclei and male and female pronuclei of fertilized sea urchin eggs were analysed by polyacrylamide gel electrophoresis in order to examine nuclear protein changes in the paternally and maternally derived chromatin following insemination. Results demonstrate major changes in both the solubility characteristics and polypeptide profiles of sperm nuclei upon insemination. Evidence is presented which indicates that at fertilization the paternally derived chromatin acquires proteins of molecular weights greater than 80,000 and a nuclear protein composition similar to that of the female pronucleus. The nuclear proteins associated with zygote nuclei were compared to those of combined male and female pronuclei and showed many similarities and some differences. Several polypeptides were present in zygote nuclei which were not observed in pronuclear extracts.


Radioautographic and biochemical studies of secretion of venom protein in the South American rattlesnake Crotalus durissus terrificus.

Protein secretion was investigated in the main venom gland of the South American rattlesnake, using radioautographic and biochemical techniques after a single intracardiac injection of L-(3,5-3H)tyrosine. All the snakes were injected at the fourth day of the secretory cycle and killed at 1/2, 1, 2, 4, 8 and 24 hours after injection. Most of the radioactive amino acid is cleared from the blood stream up to four hours after injection. On the other hand the specific activity (c.p.m./mg of protein) of the intracellular proteins reaches a peak at the 4-hour time interval decreasing afterwards. There was a good correlation between the values of the specific activity of the intracellular proteins and those of the silver grain density over the secretory cells at the several time intervals after the injection of 3H-tyrosine. The results of the quantitative analysis carried out in light- and electron-microscope radioautographs led to the conclusion that venom proteins are synthesized in the rough endoplasmic reticulum of the secretory cells, transferred to the Golgi apparatus from where they are carried to the secretory tobule lumen by the secretion granules. The fact that the values of the relative concentration of the radioactivity of he intracisternal granules double at the last three time intervals, strongly suggests that these structures are formed by the aggregation of the amorphous material present inside the cisternae of the rough endoplasmic reticulum.


Structure, function, and long-term maintenance of the isolated turtle colon.

We describe the 5-day maintenance of sacs of turtle colonic mucosa in enriched bathing solutions. The mean maximum transepithelial potential difference (PD) developed by the sacs in Ringer solution enriched with tissue-culture medium and gassed with 95% air-5% CO2 was 126 mV at 24 hours. Lower values were observed in other solutions. The PD of 24-hour sacs was partially or totally inhibited by ouabain, replacement of Na by choline in mucosal bathing fluids, or removal of Ca from serosal bathing fluids. The sacs transported Na in excess of H2O forming a dilute mucosal solution. The response of four different sac preparations (normally oriented or everted, and stripped normally oriented or everted) to long incubation were compared. Stripped normally oriented tissue developed the highest PD and maintained the lowest water content. The morphology of fresh and long-incubated tissue was examined. This investigation demonstrates that the turtle colon can be maintained in vitro for long periods, and it provides information on the morphology and physiology of this tissue.


Nerve dependent macromolecular synthesis in the epidermis and blastema of the adult newt regenerate.

The present study is an analysis of neurotrophic control of DNA and protein synthesis in the separated epidermis and blastema of the early newt limb regenerate. Previous macromolecular studies employed the entire regenerate without discrimination between its two components. The results demonstrate that the specific activities of newly synthesized protein and DNA show a nerve dependence in both epidermis and blastema. There appears to be a postdenervation rise in synthesis followed by a decline to a plateau level in both components, similar to what is reported for the whole regenerate. After two days of denervation DNA synthesis in the mesenchymatous cells is more profoundly depressed, suggesting that the epidermis is less nerve dependent.


Trophoblast regeneration by inner cell masses isolated from cultured mouse embryos.

The developmental potential of the inner cell mass (ICM) of the cultured mouse embryo was determined by testing the ability of the ICM to regenerate trophoblast in vitro. ICM's isolated by immunosurgery from either single or chimeric embryos were able to regenerate trophoblast when they were isolated at 69 hours of culture from the 2-cell stage, but they had lost this capacity by 93 hours of culture. Trophoblast regeneration by isolated ICM's did not appear to require either a critical cell mass at the time of isolation or cell proliferation during regeneration.


Epidermal regeneration and percutaneous water loss following cellophane stripping of reptile epidermis.

The histological and physiological effects of the removal of superficial corneous epidermal materials have been studied in several squamate species and a caiman. The gross and microscopic anatomy of the squamate integument has characteristics which make cellophane stripping inherently variable, but in general, when corneous materials were removed, they are replaced over a period of one to two weeks, by a tissue with the histological characteristics of the normal alpha-layer. This tissue may be produced by stimulated germinal activity and/or metaplasia of the other presumptive cell populations. In caiman, the thickness of the corneous tissues of the outer scale surface is reduced by stripping and the tissue is restored to normal in approximately two weeks by stimulated germinal proliferation. Measurements of cutaneous water loss (CWL) before, immediately after, and during two weeks post-trauma revealed the following. There is a sudden rise in CWL immediately after stripping, and values decline over the next two weeks as the corneous tissues are replaced. The results are interpreted as indicating that, as in mammals, the impermeability of the epidermis depends on the thickness of the corneous materials. In squamates it appears that the physiological barrier is the alpha-layer of the epidermal generation, and while the beta-layer cannot be excluded as playing some role in reducing the permeability of the integument, its role appears to be primarily mechanical.


Experimental studies on hatching behavior in the chick. IV. Evidence for the role of a noradrenergic mechanism.

In the present experiments we have attempted to determine whether one or more of the biogenic amines are involved in the prehatching and hatching behavior of the chick. Injection of reserpine first induces a depression in ongoing spontaneous motility on day 16 of incubation. Prior to this, reserpine has no apparent effect on embryonic behavior. Reserpine injections on days 17-19 induce a similar behavioral depression that lasts for at least six hours; by 24 hours post-injection the behavior of reserpine-treated embryos is comparable to controls. Injection of reserpine on day 20 (post-pip) delays hatching by about nine hours. Injection of reserpine into the yolk-sac of eggs prior to incubation also delays hatching by eight to nine hours. It is unlikely that the well-known cardiovascular effects of reserpine are involved in the above behavioral results since spinal embryos also exhibit a behavioral depression following reserpine treatment. Biochemical estimation of norepinephrine (NE) in the brain of reserpine-treated embryos suggest that it is release, not depletion, of the catecholamines that is responsible for the behavioral effects. Additional suport for this notion comes from experiments in which 16- or 18-day old embryos were injected with NE, L-dopa or amphetamine. In each case, a behavioral depression similar to that produced by reserpine resulted. Clonidine, a NE agonist induces a depression in certain aspects of embryonic behavior (Types 1 and 2), but also selectively enhances a corrdinated motor pattern (type 3 motility) involved in prehatching behavior (tucking). Clonidine first evokes this behavior pattern one or two days prior to its spontaneous appearance on day 16. After pipping on day 19 or 20 clonidine no longer activates Type 3 behavior, even if injected during the actual hatching process (climax). Since the alpha-adrenergic blocking agent phenoxybenzamine blocks the effect of clonidine on Type 3 tucking behavior, whereas the beta-adrenergic blocker propranolol does not, we suggest that tucking and the attainment of the hatching position are mediated by an alpha-adrenergic mechanism in the brain and/or spinal cord. Furthermore, since clonidine affects the Type 3 behavior associated with tucking, but not the somewhat similar coordinated behavior involved in hatching and emergence from the shell (climax), we propose that this later behavior pattern be given a new name, Type 4 motility.


The role of extracellular material in chick neurulation. II. Surface morphology of neuroepithelial cells during neural fold fusion.

Changes in cell surface morphology of the neuroepithelium during fusion of neural folds in the chick were studied. As the folds were about to meet, a thick extracellular coat material (ECM) appeared between the two leading edges. Cell membranes forming the fusion area were relatively smooth and heavily coated with ECM. By contrast, the apical surface of most cells lining the wall of the neural tube was folded with much less ECM. During the contact of neural folds, ECM was displaced from the space between the two leading edges, leaving a thin, closely adherent "typical" cell surface coat. Trypsin and concanavalin A inhibited proper alignment and fusion of apposing neural folds by modifying the surface of developing neuroepithelium. Results of this study support a hypothesis that ECM may serve temporarily as an adhesive to bind together the leading edges of neural folds until establishment of more intimate contacts (junctional complexes).


Immunological specificity of anti-zona binding to zona pellucida.

Biochemically purified and F(ab')2 immunoglobulin fractions were prepared from several antisera, including a human serum, which contained anti-zona pellucida activity. Anti-zona activity was monitored either by the formation of the antibody produced precipitation layer on the zona following antiserum treatment and/or by the indirect fluorescent antibody method. No changes in anti-zona activity were observed when the purified and the digested immunoglobulin preparations from each antiserum were compared to their whole serum counterparts. It is included that anti-zona binding to the zona as well as the formation of the precipitation layer on the zona is the result of a specific antigen-antibody reaction.


Oogenesis in Xenopus laevis (Daudin). VI. The route of injected tracer transport in the follicle and developing oocyte.

In Xenopus laevis, vitellogenin (the yolk precursor) is synthesized in the liver and transported via the circulatory system to the ovary. In order to reach developing oocytes where it is sequestered, it must exit the circulatory system and traverse several follicular tissue layers including the theca, the follicle cell layer, and the vitelline envelope. This study demonstrates this pathway by means of electron-opaque tracers, and follows the fate of heterologous macromolecules after their incorporation into the ooplasm. The tracers used were horseradish peroxidase, iron dextran, ferritin, and thorotrast. The bulk of the tracers exit the circulatory system through gaps between adjacent capillary endothelial cells and migrate into the connective tissue theca, where they appear randomly dispersed. All tracers, except thorotrast, penetrate the basement membrane on the distal surface of the follicle cells and pass through channels between adjacent follicle cells into the vitelline envelope and to the surface of developing oocytes, where they are incorporated by endocytosis. Endosomes which contain tracer, and also presumably vitellogenin, fuse to form primordial yolk platelets. During this fusion process an extensive network of smooth-surfaced tubules arises in the peripheral ooplasm. Endosomes and/or primordial yolk platelets continue to fuse with each other, resulting in the growth of primordial platelets which move deeper into the ooplasm, where they are transformed into yolk platelets with crystalline main bodies. Peroxidase and iron dextran remain in the superficial layer of the platelet, while ferritin is present in both the superficial layer and the crystalline main body.


Organ culture of mammalian skin and the effects of ultraviolet light and testosterone on melanocyte morphology and function.

Scrotal skin of black Long-Evans rats and human thigh skin were maintained in vitro as organ cultures for as long as 14 days, and examined histologically using the combined skin splitting and Dopa techniques. Selected rat skin cultures received testosterone in the culture medium and/or were irradiated with ultraviolet light (290-320 nm UVL). With increased time in culture, scrotal melanocytes round up and there is an increase in epidermal pigmentation. Human skin behaves similarly; after eight days in vitro human melanocytes also become rounded, but remain strongly Dopa-positive. Addition of exogenous testosterone to cultured rat skin maintains dendritic morphology of melanocytes, but cell body size is still reduced. UVL irradiation stimulates melanocytes in rat skin cultures, maintaining their dendritic morphology and increasing epidermal and dermal pigmentation. Cultured skin receiving both UVL and testosterone illustrates a synergistic effect. Electron microscopic examination of cultured rat skin shows the presence of large melanosome complexes in keratinocytes, much larger than those found in vivo. Melanocytes appear to be active as they contain an extensive Golgi zone, rough endoplasmic reticulum, and melanosomes in various stages of formation. Dermis contained many dermal melanocytes and macrophages laden with melanosomes, correlating with the increased visible dermal pigmentation in vitro. This UVL stimulation of melanocytes in our skin organ cultures contrasts with the lack of melanogenic stimulation found in melanoma cell cultures. Our findings suggest that the intact epidermal melanin unit may be necessary for UVL stimulation of melanocytes.


Proteolytic degradation of protamine during thiol-induced nuclear decondensation in rabbit spermatozoa.

Rabbit sperm nuclei decondensed when incubated with dithiothreitol and Triton X-100. Protamine isolated from these nuclei during the course of treatment exhibited marked and progressive degradation. Timed interval experiments revealed that the degradation of protamine significantly preceded sperm nuclear decondensation and reached its maximum extent before decondensation was completed. Studies with protease inhibitors demonstrated that proteolysis was involved in both nuclear decondensation and protamine degradation.


Trypsinization increases lectin-induced agglutinability of uncapacitated guinea pig sperm.

Capacitated guinea pig sperm are more agglutinable by the lectin soybean agglutinin (SBA) than uncapacitated sperm (Talbot and Franklin, '78). This study demonstrates that uncapacitated guinea pig sperm become as agglutinable by SBA as capacitated sperm when treated with trypsin, but not chymotrypsin. The pattern of lectin induced sperm agglutination after trypsinization resembles that for capacitated sperm. Also, trypsinization specifically increases SBA induced agglutination and does not affect agglutination by RCA-60; similar results are obtained during in vitro capacitation. Taken together, these data may indicate that a trypsin-like enzyme modifies the sperm surface during capacitation.


The eel retina. Receptor classes and spectral mechanisms.

Light and electron microscopy revealed that there are both rods and cones in the retina of the eel Anguilla rostrata. The rods predominate with a rod to cone ratio of 150:1. The spectral sensitivity of the dark-adapted eyecup ERG had a peak at about 520 nm and was well fit by a vitamin A2 nomogram pigment with a lambdamax = 520 nm. This agrees with the eel photopigment measurements of other investigators. This result implies that a single spectral mechanism--the rods--provides the input for the dark-adapted ERG. The spectral sensitivity of the ERG to flicker in the light-adapted eyecup preparation was shifted to longer wavelengths; it peaked at around 550 nm. However, there was evidence that this technique might not have completely eliminated rod intrusion. Rod responses were abolished in a bleached isolated retina preparation, in which it was shown that there were two classes of cone-like mechanisms, one with lambdamax of 550 nm and the other with lambdamax of less than 450 nm. Ganglion cell recording provided preliminary evidence for opponent-color processing. Horizontal cells were only of the L type with both rod and cone inputs.


The eel retina. Ganglion cell classes and spatial mechanisms.

We have been able to separate optic fibers in the eye of the eel Anguilla rostrata into two distinct classes on the basis of spatial summation properties. X fibers, the first class, are like X ganglion cells in the cat: they have null positions for contrast reversal sine gratings; they respond at the modulation frequency; and many have a strong surround mechanism. X fibers, the second class, respond with an "on-off" response to local stimulation, to diffuse light modulation, to coarse drifting gratings, and to contrast reversal gratings. We have put forward a model for the receptive field of X fibers which involves two subunits, with rectification before the subunits add their signals. This model accounts for many of the quirks of X fibers.


Interaction of chemosensory, visual, and statocyst pathways in Hermissenda crassicornis.

Neurons in the cerebropleural ganglia (CPG), photoreceptors in the eye, optic ganglion cells, and statocyst hair cells of the nudibranch mollusk Hermissenda crassicornis responded in specific ways, as recorded intracellularly, to stimulation of the chemosensory pathway originating at the tentacular chemoreceptors as well as to stimulation of the visual pathway originating at the photoreceptors. Synaptic inhibition of photoreceptors occurs via the chemosensory pathway. The possible significance of such intersensory interaction is discussed with reference to preliminary investigation of the animal's gustatory behavior and possible neural mechanisms of behavioral choice.


The permeability of single capillaries to potassium ions.

This paper reports a description of methods for determining the diffusional permeability to potassium ions of single capillaries in the frog mesentery. By means of micropipettes, injections or infusions were delivered into a single capillary. The subsequent concentration variations in and about the capillary were followed with K(+)-sensitive microelectrodes. A theoretical analysis is provided which give a quantitative frame of reference for evaluating the observed time-concentration curves in terms of capillary permeability. The advantage of single capillary studies is that the surface area through which diffusion occurs is known as is the concentration difference across the capillary membrane. Three different techniques are: (a) the "single injection" method which represents an application of the indicator diffusion technique where a high-K(+) bolus is injected into a single capillary; (b) the "sack" method which determines the rate of K(+) disappearance from within and immediately outside an occluded capillary segment, after a brief increase in intracapillary K(+) concentration; and (c) the "interstitial diffusion" method which records time and spatial distribution of K(+) in the interstitial space after a step-change in intracapillary K(+) concentration. The methods gave an average potassium permeability of the capillary membrane of 67x10(-5) cm s(-1) (SD: 23, n=26) at room temperature. These figures are clearly higher than those previously reported in mammalian capillary studies using whole-organ techniques. In terms of the pappenheimer pore model, this estimate of capillary permeability is consistent with the behavior of a membrane with a thickness of 1.0 mum which possesses equivalent pores with a radius of 110 A, a fractional pore area of 0.3 percent, and a pore density of 8 mum(-2).


Physiological basis of the selective advantage of a Spirillum sp. in a carbon-limited environment.

A Spirillum sp. and a Pseudomonas sp. possessing crossing substrate saturation curves for L-lactate were isolated from fresh water by chemostat enrichment. Their Ks and mumax values for L-lactate were: Spirillum sp., 23 micrometer and 0.35 h-1, respectively; Pseudomonas sp., 91 micrometer and 0.64 h-1, respectively. Under L-lactate limitation, pseudomonas sp. outgrew Spirillum s. at dilution rates (D) above 0.29 h-1, but the converse occurred at lower D values. The advantage of Spirillum sp. increased with decreasing D until, at D = 0.05 h-1 (i.e. L-lactate concentration of approximately 1 micrometer), Pseudomonas sp. was eliminated from the culture essentially as a non-growing population. In Spirillum sp. the Km for L-lactate transport (5.8 micrometer) was threefold lower than in Pseudomonas sp. (20 micrometer); Spirillum sp. also possessed a higher Vmax for the transport of this substrate. The surface to volume ratio was higher in Spirillum sp. and increased more markedly than in Pseudomonas sp. in response to decreasing D. Thus, a more efficient scavenging capacity contributes to the advantage of Spirillum sp. at low concentrations of the carbon source. Although most of the enzymes of L-lactate catabolism were more active in Pseudomonas sp., NADH oxidase activity was about twice as high in Spirillum sp.; and, unlike Pseudomonas sp., the cytochrome c content of this bacterium increased markedly with decreasing D. A more active and/or more efficient respiratory chain may therefore also play a role in the advantage of Spirillum sp. The other factors which appear to be involved include a lower energy of maintenance of Spirillum sp. [0.016 g L-lactate (g cell dry wt)-1 h-1 compared with 0.066 in Pseudomonas sp.] and a lower minimal growth rate.


A study of the interaction between oral streptococci and hard surfaces.

A rotating disc method was used to compare the tendencies of two oral streptococci to deposit on to glass and polystyrene surfaces from electrolyte solutions of varying ionic strength. Streptococcus salivarius had a greater tendency to deposit than had Streptococcus mitior under these condition. In addition to the balance of van der Waals' forces of attraction and electrostatic forces of repulsion, it is suggested that the adsorption to the glass and polystyrene surfaces of material present in the outer layers of the cell wall could play a significant part in the deposition of S. salivarius.


Characterization and identification of coagulase-negative, heat-stable deoxyribonuclease-positive staphylococci.

Various characteristics of 13 coagulase-negative, weakly heat-stable deoxyribonuclease-positive staphylococci from human, veterinary and food sources were determined in an effort to identify them. Nine of the isolates were identified as coagulase-negative Staphylococcus aureus (2), Staphylococcus xylosus (2), Staphylococcus simulans (3), Staphylococcus capitis (1) and Staphylococcus sciuri subsp. lentus (1); the other four isolates, from food and veterinary sources, could not be identified as currently accepted or proposed species. Teichoic acid and peptidoglycan compositions were used as key taxonomic characteristics. The determination of heat-stable deoxyribonuclease activity can be useful to detect coagulase-negative S. aureus strains. However, this activity also appears to be present in strains of other staphylococcal species.


The role of carbonate in the metabolism of glucose by Butyrivibrio fibrisolvens.

The amount of Na2CO3 added to semi-synthetic medium determined the length of the lag phase, the growth rate and the dry weight of three strains of Butyrivibrio fibrisolvens (WV1, NOR37, B835). With increasing CO3(2-) concentration the molar growth yield of bacteria, from glucosewas increased and, of the fermentation products, formate increased more than the other acids. CO3(2-)-limited cultures of strain WV1 (Group 2 Butyrivibrio) and strain NOR37 (Troup 1 Butyrivibrio) incorporated 14CO3(2-) into lactate and formate. In NOR37, lactate and formate had equal specific activities; in WV1, the formate specific activity was twice that of lactate. Strain WV1 had an active pyruvate synthase and an energy-dependent exchange between CO3(2-) and formate was demonstrated. In strain WV1 butyrate was produced mainly from glucose.


An alternative pathway for the degradation of endogenous fructose during the catabolism of sucrose in Rhodopseudomonas capsulata.

Sucrose catabolism was studied in Rhodopseudomonas capsulata. Sucrose was hydrolysed by the action of a constitutive cytoplasmic sucrase. The use of a glucose-6-phosphate dehydrogenase-deficient mutant and radiorespirometric experiments demonstrated that both the glucose and fructose moieties of sucrose were catabolized via the Entner-Doudoroff pathway. This result was confirmed by enzyme analysis and studies on sugar assimilation. All the enzymes of the Entner-Doudoroff pathway were present in bacteria grown on secrose but fructokinase (EC 1.7.1.4) activity was relatively low. In contrast, phosphoenolpyruvate:fructose phosphotransferase and 1-phosphofructokinase, the key enzymes for the catabolism of exogenous fructose, were only partially induced. Bacteria grown on sucrose and treated with chloramphenicol were, therefore, not able to assimilate exogenous fructose. We conclude that under these conditions endogenous fructose is catabolized via the Entner-Douboroff pathway, while exogenous fructose is degraded via fructose 1-phosphate and the Embden-Meyerhof pathway.


Establishment and characterization of a subacute sclerosing panencephalitis (measles) virus persistent infection in BGM cells.

Infection of BGM cells with the Halle isolate of subacute sclerosing panencephalitis (SSPE) gave rise to a persistent infection (BGM/Halle), whereas infection of another African green monkey kidney cell line (Vero) under identical conditions led to a lytic infection. The BGM/Halle cells multiplied more slowly than the non-infected cells (even when the medium was changed daily). Under such conditions 10(7) to 10(8) p.f.u./ml/24 h of measles virus was released into the medium. It was established that the persistent infection was not due to the accumulation of thermosensitive mutants and that the virus was not modified as measured by several biological parameters. The virus released from BGM/Halle cells had, however, acquired an ability to give rise to a persistent infection in Vero cells. The quantity of virus released from persistently infected Vero cells was very low (10(2) to 10(3) p.f.u./ml). It was concluded that a host-cell factor plays a role in the restriction of virus replication.