The study of (Methyl-3H)decamethonium dichloride incorporation into normal and dystrophic mouse muscle. 1. (Methyl-3H)decamethonium dichloride was injected intravenously into the tail vein of dystrophic and normal mice of the Bar Harbour strain 129 ReJ/dy in paralysing doses. 2. Scintillation counts were made of 1 mm sections of diaphragm and tibialis anterior which showed a normal distribution of tritiated decamethonium in the dystrophic animals. 3. Intraperitoneal injections of L-(gamma-3H)leucine were made into dystrophic and normal mice. Examination of diaphragm and tibialis anterior by scintillation counting showed the abnormal uptake typical of dystrophic involvement of murine muscle. 4. The normal distribution of (methyl-3H)decamethonium dichloride uptake by the dystrophic muscle does not support the concept of active denervation in this disease.


Plasma kininogen during the oestrous cycle, early pregnancy and pseudopregnancy in the rat. 1. Changes in the plasma kinin precursor, kininogen, occur following treatment with oestrogens and progestogens. This work was undertaken to attempt to relate plasma kininogen values to hormonal changes in various reproductive states. 2. During the oestrous cycle kininogen concentrations follow a nychthemeral rhythm, kininogen depletion occurring during the increase in general activity of the rat. 3. Superimposed on the nychthemeral changes in kininogen concentration are changes which may be related to the hormonal events of the oestrous cycle. 4. During early pregnancy and pseudopregnancy the kininogen level rises; this increase may be due to changes in the circulating levels of oestrogens and progestogens. 5. It is suggested that the changes in kininogen concentration may result from utilization of kinin which could be of functional significance.


Renal handling of phenol red. II. The mechanism of substituted phenolsulphophthalein (PSP) dye transport in rabbit kidney tubules in vitro. 1. The uptake of various substituted phenolsulphophthalein dyes by cortical slices of rabbit kidney has been studied in detail in order to obtain more information on the secretory system for organic anions. 2. The rate of initial uptake of dyes and the accumulation after incubation for 2 hr under aerobic conditions increased in the order: phenol red (PR) greater than bromophenol blue (BPB) greater than bromocresol green (BCG) greater than bromothymol blue (BTB), while the reverse order of uptake was observed under anaerobic conditions. There was no difference between the uptake of BTB under aerobic and anaerobic conditions. 3. The accumulation of dyes under anaerobic conditions could be accounted for by binding to tissue constituents. In comparison with PR (Sheikh, 1972), the substituted dyes were found to interact extensively with the 700 G (cell membranes) and cytosol fractions of renal homogenates. 4. Low concentrations of the substituted dyes efficiently inhibited the accumulation of rho-aminohippurate (PAH). The concentration of dye resulting in 50% inhibition of PAH accumulation (KI) agreed well with concentrations estimated to sustain 50% of maximal dye transport (KM). On this basis the affinity of the dyes for the transport system increases in the order: PR less than BPB less than BCG less than BTB. 5. Probenecid, 2,4-dinitrophenol, PAH, octanoate and succinate affected to a smaller extent the uptake and binding of BPB and BCG by renal tissue than that previously shown for PR (Sheikh, 1972). No inhibitory effect of these substances on the accumulation of BTB by kidney tissue was observed. 6. The binding of PSP dyes by phospholipid vesicles (liposomes) and a representative binding protein, human serum albumin, exhibited close similarity to that of binding by renal tissue. Partition experiments involving octanol-water phases indicated that the hydrophobicity of the dyes increased in the order: PR less than BPB less than BCG less than BTB. 7. The results indicate that BTB, despite its inhibitory potency, is not transported by the organic anion system. BPB and BCG are transported to a lesser extent, and interact more strongly with the transport system than does PR. It is suggested that the substituted dyes by virtue of hydrophobic interaction with the transport system reduce the movement of the mobile part of the transport system.


Aspects of intestinal folate transport in the rat. 1. In vitro preparations of rat jejunum were used to study the metabolic dependence, the structural specificity, and the pH sensitivity of the folic acid absorption process. 2. The presence of 2:4 dinitrophenol, and the absence of oxygen, in the muscosal bathing medium both led to a decrease in the tissue accumulation and serosal transfer of folic acid by everted sacs. 3. 10-formylfolic acid, present in the mucosal medium at a molar ratio of 10:1 with labelled folic acid, appears to compete for tissue accumulation sites but has no significant effect on serosal transfer. 4. The efflux of folic acid from pre-loaded jejunal sacs is stimulated by the presence in the mucosal medium of the folic acid and related compounds. Pteroyl-L-glutamic acid, 10-formylfolic acid and methotrexate elicit a significant increase in the efflux rate; pteroyl-D-glutamic acid was significantly less effective and pteroic acid had no effect. 5. The uptake of folic acid by isolated jejunal cells prepared by enzymic disaggregation of the mucosa, was found to be influenced by the pH of the bathing medium, uptake being enhanced at a pH of between 5 and 6. 6. It is concluded that the effect of metabolic inhibitors and acid pH conditions on the uptake of folic acid in vitro is consistent with a passive absorption mechanism, influenced in intact preparations and in vivo by the jejunal pH microclimate. However the occurrence of competitive inhibition and stimulated efflux may indicate the existence of a structurally specific accumulation process at some site, or sites, within the mucosa.


The preparation of human red cell ghosts containing calcium buffers. 1. Ca buffers may be introduced into human red cells by reversible haemolysis. The resealed ghosts retain Ca and chelating anions in the same ratio as in the haemolysing solution, enabling the intracellular Ca2+ concentration to be calculated simply. 2. The passive permeability of the ghosts to Na and Cl is unaffected by intracellular Ca2+ concentrations in the 10(-8)-10(-4) M range, whereas the K permeability is greatly increased at concentrations above 10(-7) M. 3. These preparations enable Ca-dependent K movements to be studied under stable conditions. When the ghosts contain about 5 X 10(-6) M-Ca2+, over 96% of K transport occurs via the Ca-sensitive route.


Calcium-dependent potassium exchange in human red cell ghosts. 1. The properties of the Ca-dependent K transport system of human red cell ghosts have been examined under equilibrium exchange conditions. 2. K transport is stimulated half-maximally by about 0-4muM-Ca2i+ or 5muM-Sr2i+, but much higher concentrations of Ba2i+ give only slight stimulation. Mg is a weak antagonist to Ca. 3. The free Ca2+ concentration in human red cells is estimated to be below 0-25muM. 4. The curve relating the rate of K transport to the intracellular Ca2+ concentration is complicated and suggests that internal Ca acts at three or more sites. 5. K, Rb and possibly Cs ions are transported by the Ca-dependent system. Under comparable conditions the relative rates are 1(K):1-5(Rb): less than 0-05(Cs). 6. No Ca-dependent transport of Na, Li or choline could be detected. If Na is transported, it must be at less than 1/40 of the rate of K. 7. The rate of K transport is almost linearly related to the K concentration in the 0-200 mM range, but the curve is sigmoid close to the origin. 8. Intracellular, but not extracellular Na inhibits K transport, in a way that suggests competition with K at more than one site. 9. These results suggest that the transport system has a complex mechanism.


A study of the transport and permeability properties of the guinea-pig amniotic membrane. 1. The simultaneous measurement of the two-way sodium flux across the in vitro amniotic epithelium did not reveal a preferential active movement of sodium in either direction. The amnion is thus unlikely to be the site of formation of amniotic fluid. 2. The permeability of the amniotic epithelium to some non-electrolytes has been measured with isotopes and was found to be generally low in relation to the thinness of the tissue. The permeability to non-electroytes would appear to be depebility to sodium and to non-electrolytes was found to vary with gestational age. The amnion from animals of 61-70 days' gestation was markedly more permanent than those at 50-60 days (term 70 days).


The role of carbonic anhydrase inhibitors on anion permeability into ox red blood cells. 1. Organic anion permeability in ox red blood cell was measured by studying steady-state self-exchange of oxalate, chosen as a prototypical substrate of the organic anion transport system previously described; chloride self-exchange measured the inorganic anion permeability. 2. Carbonic anhydrase inhibitors of the sulphonamide class inhibit both organic anion self-exchange (A-/A-) and chloride self-exchang (CL-/CL-) although carbonic anhydrase plays no role in these exchanges. These results confirm the conclusions already published that sulphonamides can act directly on the cellular membrane as specific inhibitors of anion transport. 3. There is a correlation between the chemical structure of the sulphonamides and their capacity for inhibiting transmembrane anionic exchange. It is of significance that N-sulphamyl substitution, which abolishes the carbonic anhydrase inhibitory potency, does not destroy anionic inhibitory capacity and may even increase it. 4. For each sulphonamide the capacities for inhibiting chloride transport and oxalate transport are strictly identical. Inhibition appears non-competitive. 5. The temperature sensitivity of oxalate self-exchange is exactly the same as that of chloride self-exchange. From this, and from the nature of their inhibition by sulphonamides, it is proposed that chloride and organic anions share the same transport mechanism. 6. In the light of the present results the chloruretic action of sulphonamides in various tissues, in particular the kidney, is discussed.


The effect of a meal of meat on glomerular filtration rate in dogs at normal urine flows. 1. The exogenous creatinine clearance of conscious dogs has been measured by a method in which no loading doses of water or saline were given. The urine volume was thus in the normal range, 0-1-0-3ml./min. 2. Under these conditions, the exogenous creatine clearance of fourteen dogs, measured 17 hr after a meal, was 2-74 ml./min kg-1+/-0-54 (s.d.). This is about 40% lower than values usually regarded as "normal." 3. A meal of meat, 10g/kg, increased exogenous creatinine clearance reflects an increase in glomerular filtration rate. Since this occurs with small doses of meat, increase in glomerular filtration may be important in normal renal function of dogs.


The excretion of urea by dogs following a meat meal. 1. After a meal of meat (10g/kg), urea excretion in dogs increased by about 200%, plasma urea by 60% and exogenous creatinine clearance by 40% in comparison with control experiments. 2. Urea, given by stomach tube in doses producing the same increase in plasma urea, caused urea excretion to increase by only 90%, with no increase in creatinine clearance. With the increased glomerular filtration rate after meat there was added excretion of urea. 3. In control experiments and after urea, the rate of excretion of urea was directly proportional to plasma urea. The ratio urea clearance/creatinine clearance, was 0-45. 4. After meat, urea clearance increased more than creatinine clearance, the ratio increasing to 0-55, i.e. a smaller fraction of the filtered urea was re-absorbed after meat. 5. After meat, 10g/kg, the rate of urea production rose to 230-600 mumole/min for 4-6 hr.


Inhibition of in vitro concentrative prostaglandin accumulation by prostaglandins, prostaglandin analogues and by some inhibitors of organic anion transport. 1. Incubation of rabbit choroid plexus, anterior uvea (iris-ciliary body complex) or slices of kidney cortex in a medium containing tritium-labelled prostaglandin F(2alpha) ([3H]PGF(2alpha) or E1 ([3H]PGE1) results in a four- to thirteenfold concentrative accumulation of 3H activity. 2. Addition of PGF(2alpha, PGF(1) or PGA(1), any one of five PG analogues or a PG precursor, arachidonic acid, at a concentration of 10(-4) M reduced the active accumulation of [3H]PGs by 47-97%. Octanoic acid, at the same concentration, had only a moderate effect on the choroid plexus and no significant inhibitory effect on [3H]PFG(2alpha) accumulation by anterior uvea or kidney cortex. 3. Inhibition was also obtained with 2 mM iodoacetate (under anaerobic conditions) and with 10(-4) M diploretin phosphate, probenecid, iodipamide, indomethacin or dinitrophenol. Perchlorate (10(-4) M) and iodide (10(-4) or 10(-3) M) had no inhibitory effect while 10(-4) M p-aminohippuric acid had a significant inhibitory effect on the kidney cortex at a concentration of 10(-4) M and on the anterior uvea at 10(-3) M. 4. It is concluded that the apparent carrier mediated PG transport systems of the choroid plexus, anterior uvea and kidney cortex are not related to the iodide transport system, but may represent a subcomponent of the iodipamide transport system of these tissues. 5. These results suggest that the systemic distribution and the rate of renal excretion of PGs could be altered by high concentrations of PGs, pharmacologically less active PG analogues, some inhibitors of organic acid transport, and by some inhibitors of PG synthesis and PG action.


[Heat debt and thermal insulation in women exposed to cold : contribution of direct calorimetry to the study of a mathematical model (author's transl)]. 1. Measurements of total heat losses by direct calorimetry, metabolic heat production by indirect calorimetry, body temperatures by thermometry, and thickness of subcutaneous fat with skin-fold calipers were made in four groups of subjects (anorexic, controls, trend to obesity, and obesity) at ambient temperatures of 28 degrees C and 20 degrees C. 2. At 28 degrees C, the four groups of subjects reached thermal equilibrium after 30 min. 3. Both metabolic heat production and total heat losses were lower in the anorexic group than in the control group. 4. Body thermal insulation was not simply related to the thickness of subcutaneous fat (passive insulation), but was actively regulated in such a way that thermal balance was attained by all subjects at 28 degrees C. Body tissues underlying the subcutaneous fat contributed to the thermal insulation of the subjects at both 28 degrees C and 20 degrees C. 5. At 28 degrees C, total body thermal insulation was higher in anorexic subjects than in controls. 6. At 20 degrees C, heat debt was similar in three of the four groups : the anorexic subjects showed a higher debt. 7. A highly significant correlation between subcutaneous fat and weight/area ratio, was found. 8. The heat exchange coefficient of radiation and convection was found to be 6,47 Wm-2 degrees C-1. 9. By combining our measured values with those of various tissue physical characteristics, it was possible to produce a mathematical model. With this model one can calculate the penetration of the thermal gradient into the body, and estimate the mean temperature of each tissue participating in the thermal insulation for moderately cold ambient temperatures.


Influence of mechanical properties on the relation between EMG activity and torque. An attempt was made to determine the average stiffness and viscosity of the muscle groups responsible, in human subjects, for the flexion and extension of the forearm, when these movements are produced intentionally. To this end, the subjects were instructed to produce sinusoidal movements by tracking acoustic and visual signals. 1. By recording simultaneously the sinusoidal angular variations and the EMG activity of both triceps and biceps it was possible to determine the phase angle between EMG and inertial torque at different frequencies (between 0.2 and 5 Hz). 2. The known phase relations between EMG and torque were then subtracted from this plot obtaining, therefore, the phase characteristics of the mechanical system (forearm-lever complex). 3. The average resonant frequency for different amounts of intentional contraction of the muscles responsible for the motion was 0.8 Hz, leading to an estimate of the average stiffness of 2.57 kgw.m/rad. 4. The slope of the phase in proximity of the resonant frequency lends an estimate for the viscosity of 0.85 kgw.m.sec/rad. 5. The contribution to the motion by elastic forces and the active contraction due to intentional motor commands was also considered.


[Influence of the acclimation temperature on the phospholipid metabolism of the fresh water ell (Anguilla anguilla) (author's transl)]. Lowering of the acclimation temperature of the eel induced a reduction of 32P incorporation into the lipid phosphorus of various tissues. This effect was partly the result of a slight decrease of the inorganic phosphate exchange and metabolism of tissues. 2. The variation of the 32P incorporation into the various phosphatides was different according to the tissue ; gill and kidney phospholipids being the most effected. At high temperature (22 degrees C), the turnover of sphingomyelin and phosphatidyl-choline was four or seven fold higher in all tissues than at low temperature. At low temperature (12 degrees C), the incorporation of 32P into gill and kidney phosphatidylinositol and gill diphosphatidyl-glycerol was the same as at high temperature. The kidney diphosphatidyl-glycerol turnover was affected to the same extent as the other phosphatides by high acclimation temperature. The gill phosphatidyl-ethanolamines had a relatively higher turnover at low temperature. 3. The acclimation of the eel at low temperature provoked an increase of the turnover of phosphatidyl-ethanolamine and diphosphatyl-glycerol into the gill, parallel with an increase of some enzymatic activities. 4. The variation of the acclimation temperature may impose restrictions on the turnover of some phosphatides. There is a limited action of the temperature on the turnover of metabolically active phosphatides of the osmoregulatory organs, such as gill phosphatidyl-inositol and diphosphatidyl-glycerol or kidney phosphatidyl-inositol. 5. The significance of these findings is discussed in relation to the role of phospholipids in the cell and to the physiological functions of the various organs of the eel.


Variation in intramembrane components of Trypanosoma brucei from intact and x-irradiated rats: a freeze-cleave study. Additional information on host interactions with trypanosomatid membranes was obtained from studies of a monomorphic strain of Trypanosoma brucei harvested at peak parasitemia from intact and lethally irradiated rats. Pellets of trypanosomes were fixed briefly in glutaraldehyde and processed for thin section electron microscopy or freeze-cleave replicas. Observations of sectioned material facilitated orientation and comparison of details seen in replicas. Fracture faces of cell body and flagellar membranes as well as 3-dimensional views of the nuclear membrane were studied. Cell body membranes of 80% of the organisms from intact rats contained random arrays of intramembranous particles (IMP). Aggregated clusters of particles appeared on the fracture faces of 20% of the trypanosomes. Some of these membranes had nonrandomly distributed particles aligned in distinct rows on the outer fracture face of both cell body and flagellum. Many inner face fractures of the cell body membranes had a particle arrangement similar to the longitudinal alignment of cytoskeletal microtubules. No aggregated particle distribution was seen in membranes of trypanosomes harvested from lethally irradiated rats. Replicas of trypanosome pellets also had plasmanemes as a series of attached, empty, coated membrane vesicles. These structures were found in close association with, as well as widely separated from the parasites. The shedding of these vesicles and the variation of particles in cell body membranes are discussed in light of antibody-induced architectural and antigenic changes in surface properties of trypanosomatids. The convex face of the inner membrane of the nucleus also is covered with randomly arrayed particles. More IMP were observed on the inner than on the outer nuclear membranes. Images of nuclear pores were also seen. The importance of these structures in drug and developmental studies of trypanosomes is discussed. On fracture faces of the flagellar membrane there were miniature maculae adherentes, unique to the inner fracture face and occurring only at regions of membrane apposition between cell body and flagellum. Each cluster of particles exposed by the freeze-cleave method corresponds to an electron-dense plaque seen in thin section images. However, because of a unique fracture pattern, these plaques were not revealed on the apposing body membranes, as illustrated in thin sectioned organisms.


Feeding mechanisms in extracellular Babesia microti and Plasmodium lophurae. Although large hemoglobin inclusions are observed in intraerythrocytic Babesia microti parasites, they are absent from parasites freed of hamster red cells by immune lysis with anti-hamster erythrocyte serum. Babesia microti has no cytostome. This parasite, therefore, does not appear to feed by phagocytosis of large boluses of hemoglobin, as does Plasmodium. To determine whether Babesia can pinocytose protein, free parasites were fed ferritin in an in vitro system. Ferritin was taken up from the entire cell surface into narrow channels within 15 min at 37 C. Only merozoites, with their pellicular complex, failed to take up the protein. By 60 min, the ferritin was highly concentrated in many channels and vesicles, which formed interconnecting stacks. The ferritin-containing channels became associated with membrane whorls of the multimembranous structure. Membrane whorls were also observed in the process of extrusion in samples incubated for longer times. These events may represent steps in the digestion and excretion of the pinocytosed protein. Empty channels formed when Babesia was fed albumin. The diaminobenzidine reaction for hemoprotein was positive for the channels in both free and intraerythrocytic babesias. The staining reaction was completely inhibited by cyanide, but not at all by aminotriazole. These results further suggest that Babesia pinocytoses hemoglobin in vivo. Plasmodium lophurae parasites freed of red cells by immune lysis are surrounded by 2 membranes and apparently can ingest ferritin only through the cytostome. Extracellular cytostomal feeding involves both membranes, as it does in vivo. Ferritin was found in food vacuoles, some of which contained hemoglobin ingested before parasite isolation, connected to or near the cytostome. In both Plasmodium and Babesia low temperature inhibited ferritin uptake.


Ultrastructure of intraerythrocytic Babesia microti with emphasis on the feeding mechanism. Babesia microti is a highly polymorphic organism. To unravel its fine structure and the function of organelles it was necessary to resort often to serial sections. A single plasma membrane covers the organism. In trophozoites approaching reproduction, segments of double membranes can be found below the plasma membrane. In electron micrographs of poor resolution these segments of double membranes look like pieces of thick membranes and they were often thought to be a thick 2nd membrane. Before the segments of double membranes appear 2 other organelles are formed in older trophozoites: micronemes and rhoptries. There are indications that these structures originate from vesicles of the Golgi apparatus. Large dense bodies of the same structure as the host cytoplasm are not food vacuoles but merely invaginations of host cytoplasm, as found in serial sections and in organisms removed from the host cell. Feeding in Babesia seems to take place by a special organelle composed of tightly coiled double membranes located partly inside and partly outside the parasite. It is assumed that extracellular digestion of host cytoplasm take place through this organelle. The nucleus remains undifferentiated throughout the whole intraerythrocytic stage. It becomes irregular, loboid, but does not divide and remains a single body until the late stage of reproduction when only a small portion, a bud, extends into the forming merozoite.


Ultrastructure of the peripheral zone of a Glugea-induced xenoma. The Glugea stephani-induced xenoma in the winter flounder, Pseudopleuronectes americanus, is a large spherical host-parasite complex, up to 4.0 mm in diameter, with the host and parasite components of the xenoma being most active in the peripheral zone. The xenoma has an extensive periodic acid-silver methenamine-positive surface coat covering the plasma membrane. The surface of this membrane is amplified by the presence of numerous folds and fine tubular extensions. The peripheral zone of the xenoma contains many host-cell mitochondria in addition to numerous microsporidan parasites. At the ultrastructural level, the peripheral zone of the host-cell cytoplasm appears normal. Inside the peripheral region of the 0.4-1.0 mm xenoma, the host-cell component largely disintegrates in the presence of microsporidan parasites undergoing sporogenesis.


Axenic cultivation of Phytomonas davidi Lafont (Trypanosomatidae), a symbiote of laticiferous plants (Euphorbiaceae). Phytomonas davidi (Trypanosomatidae) originally discovered by Lafont in 1909 on the island of Mauritius was rediscovered in Euphorbia cyathophora in Florida. Successful cultures were established in diphasic medium consisting of duck blood agar and modified Phillips' medium as overlay. Optimal growth was obtained when Mansour's medium was used as overlay and poorest growth when Cowperthwaite's medium buffered at pH 5.0 was utilized for this purpose. Marked changes tending toward choanomastigotes rather than the elongate twisted promastigotes were observed in cultures.


Symbiote-free hemoflagellates, Blastocrithidia culicis and Crithidia oncopelti: their liver factor requirement and serologic identity. Several aposymbiotic strains of Blastocrithidia culicis and Crithidia oncopelti were cultivated in Trager's chemically defined medium as well as in a blood broth, both supplemented with 0.25% (v/v) liver extract concentrate. For all such strains, the liver extract was found to serve as an essential growth factor in the defined medium and as growth promoting additive in the blood broth. The active molecules were found to be water-soluble, heat stable, dialyzable, and probably nonlipid fractions. Antisera were developed in rabbit against all the available aposymbiotic strains. An almost total cross-reactivity at very high titers was observed in reciprocal agglutination test using strains with and without the bacterial symbiotes. These results indicate that the loss of the symbiotes does not affect the antigenic identity of B. culicis and C. oncopelti.


Infectivity of Leishmania donovani amastigotes and promastigotes for golden hamsters. Intracardial injection of hamsters with from 5 to 114 million amastigotes or promastigotes of Leishmania donovani and screening of the 8th-day liver impression smears, provides a rapid and reproducible method for assaying infectivity. Amastigotes are at least 10X more infective than promastigotes, and log-phase promastigotes act as a single infective population for hamsters.


The cell surface of Trypanosoma musculi bloodstream forms. II. Lectin and immunologic studies. Living  Trypanosoma musculi bloodstream trypomastigotes were agglutinated specifically with concanavalin A (ConA), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and fucose-binding protein (FBP). The agglutination with these lectins of living cells from which the coat was removed by trypsinization was the same as with intact trypanosomes. Glutaraldehyde or formalin fixation did not affect the results with regard to agglutination with WGA, SBA, and FBP, but lower agglutination with ConA was observed upon fixation. By using a dense iron-dextran marker many fewer ConA marker particles were localized at the fine structural level in the intact than in trypsin-treated trypanosomes. On the basis of the results obtained by agglutination and electron microscopy, it is likely that fixation  cross-links intact surface-coat components associated with the ConA binding sites. It is  evident from the studies in which lectins were employed that ligands containing alpha-D-mannose, N-acetylglucosamine, N-acetylgalactosamine, and alpha-L-fucose are randomly distributed in the outer surface of the pellicular and flagellar membranes of T. musculi trypomastigotes. Results obtained with alpha-amylase- and dextranase-treated trypanosomes suggested that lectin-binding sugar ligands in the cell surface were not directly associated with alpha-1,4 or repetitive alpha-1,6 glucan-bonded polysaccharide moieties. Similar conclusions can be drawn on the basis of neuraminidase treatment with regard to N-acetylated neuraminic acids. After thorough washing, intact, but not trypsin-treated trypomastigotes were agglutinated specifically with antisera against whole mouse serum and against mouse IgG. Evidently, adsorbed constituents of mouse serum are regular components of the T. musculi surface coat. After incubation in dilute whole mouse serum or in mouse IgG solutions, also the trypsinized cells were agglutinated by the 2 antisera. No such results were obtained with trypsinized cells incubated in serum-free buffers. It was concluded that mouse serum proteins were readily readsorbed on, and firmly bound to the trypsinized cells' surfaces. Specific agglutinations were obtained with trypsinized cells after incubation in dilute rat, rabbit, bovine, and human sera and in solutions of rat and rabbit IgG in reactions with the corresponding antisera. It seems, therefore, that the host serum proteins are adsorbed nonspecifically to the cell surface of trypsinized T. musculi bloodstream forms. When examined by electron microscopy, the intact trypomastigotes were covered by an ununiform, slightly granular, fibrillar extracellular coat, applied to the entire outer lamina of the pellicular and flagellar membranes. No indication of such a coat was noted in the trypsinized organisms. Flocculent surface coat-like matrix could, however, be discerned in cells which, after trypsinization, were incubated in various sera.


Does a histidine-rich protein from Plasmodium lophurae have a function in merozoite penetration? Autoradiography was used to localize the distribution of L-[3H]histidine incorporated in vitro by developing  segmenters of Plasmodium lophurae. Under conditions used for the visualization of high specific activity loci, radioactivity appeared associated mainly with the histidine-rich protein of cytoplasmic granules as well as with rhoptries and micronemes of merozoites. The isolated histidine-rich protein caused agglutination of erythrocytes and increased their osmotic fragility. Based on the observed evidence suggesting the presence of this histidine-rich protein in the polar organelles of merozoites and its reactivity with erythrocyte membranes, the hypothesis that such a protein may have a function in the penetration of merozoites is proposed.


Demonstration that Leptomonas pessoai Galvão, Oliveira, Carvalho & Veiga, 1970, is a Herpetomonas. Leptomonas pessoai from the reduviid hemipteron Zelus leucogrammus, was cloned. The original strain (ATCC 30252) and clones can differentiate from promastigote to opisthomastigote. Differentiation is faster at high temperature (37 C) and in a defined medium as compared with a complex medium. It is suggested that Leptomonas pessoai be designated Herpetomonas samuelpessoai.


Demonstration of concanavalin A receptors on Leptomonas pessoai cell memebrane. Leptomonas pessoai promastigotes cultivated in a synthetic medium were agglutinated with concanavalin A (ConA). Agglutination was predominantly of the flagellar-flagellar type, and was inhibited with sucrose or alpha-methyl-D-mannoside. Cell surface polysaccharides and/or glycoproteins were demonstrated by several cytochemical methods at the fine-structural level. A Con A-horseradish peroxidase-diaminobenzidine (DAB) technic was used to detect Con A receptors in the pellicular membrane of the flagellar pocket region and in the flagellar membrane proper. Somewhat less of the Con A-DAB reaction product was observed in the pellicular membrane enclosing the rest of the cell.


Effects of actinomycin D on generation time and morphogenesis in Paramecium. The sensitivity of Paramecium tetraurelia (=P. aurelia syngen 4) cells to pulse treatments with various doses of Actinomycin D (AMD) was estimated by comparing the generation times of treated and untreated sister cells. It was found that the delay of division in treated cells depended on the concentration of AMD, on their "age" at the time of the pulse treatment, and on their individual sensitivity. Sensitivity of Paramecium to AMD changes during the cell cycle in a predictable way. About 3 1/2 hr before the normally expected cell fission (total generation time approximately 5 1/2 hr) there is a decrease of sensitivity. Thereafter, the cell enters a new stage with a progressive increase of sensitivity. This 2nd phase ends at the "transition point" (approximately 2 hr before cell division), when sensitivity drops abruptly. The division process itself may be altered and slowed down by high concentrations of AMD, even if the drug is applied after the transition point, but this process can never be completely annulled. The impairment of the division mechanism may lead to morphologic anomalies in the offspring. Resorption of oral anlagen in P. tetraurelia probably never occurs during the cell cycle after AMD treatment. The reason for individual variability of the cells, mechanisms controlling development, and the question of an obligate sequence of gene action in each cell cycle are discussed.


The new colposcopic terminology.

The new colposcopic terminology. A generally acceptable scheme for the classification of colposcopic findings is critical for the more widespread acceptance of this valuable diagnostic tool. Older schemes have tended to confuse students. The scheme described in this article sets appearances against an order of events in time and place based on the biological life history of the organ. This amounts to the history of exposed columnar epithelium as it changes, by a typical or atypical process, into squamous epithelium to produce, respectively, a typical or atypical transformation zone. The former produces a homogeneous appearance, the latter a heterogeneous appearance requiring further subdivision by the use of the categories of white epithelium, blood vessel abnormalities such as punctation and mosaic and other atypical patterns, and leukoplakia. Not all of these abnormal appearances are associated with greatly altered histological appearances and, therefore, a further system of their grading is introduced. Other categories include appearances associated with overt cancer, with miscellaneous noncancerous conditions and with states in which the complete transformation zone is not viewed and, therefore, the colposcopic findings are not satisfactory. Finally, the present scheme is integrated as far as possible with older schemes.


Colposcopic evaluation of cervical neoplasia in pregnancy. The need for histologic examination of the cervix during pregnancy is not uncommon. Classically, the cone biopsy has been the diagnostic procedure of choice, but this procedure is attended by a significant and excessive complication rate. The cumulative data strongly supports the conclusion that the combination of cytology and colposcopically directed biopsy can be relied upon to provide an accurate diagnosis in a high percentage of patients. Colposcopy should be a routine diagnostic procedure in the evaluation of patients with abnormal Pap smears or grossly abnormal cervices.


Colposcopy screening for cervical cancer in a family planning program. A brief history is presented of colposcopy in the United States and at Louisiana State University. Incorporation of colposcopy screening as a part of the cervical cancer screening program in the Louisiana Family Planning Program is discussed, and the reasons for the need of "in house" colposcopy service are outlined. Data of the Louisiana Family Planning Program Colposcopy Service for the three-year period 1972 through 1974 are presented. Analysis of these data reveals that cytology when used without colposcopy fails to reveal the presence of major cervical pathology in 30.2% of patients. It is concluded that colposcopic screening must be a part of all family planning and cervical cancer detection programs.


Histopathologic spectrum of benign proliferative and intraepithelial neoplastic reactions of the uterine cervix. A working model for the histogenesis of carcinoma of the uterine cervix is summarized in Table I. The inclusion of squamous metaplasia in this chart does not imply that this reaction falls into the spectrum of cervical neoplasia or is necessarily an antecedent to neoplasia. It does simply imply that the carcinogenic event or events apparently occur in or involve an epithelium that is indistinguishable from squamous metaplasia. The chart intentionally implies that the lesions mentioned are not separate diseases but arbitrary points in the spectrum of cervical neoplasia. It must be emphasized that one stage does not necessarily progress to the next and that at any stage up to indisputable cancer the changes may regress, persist or progress. The careful evaluation of histologic material from the uterine cervix will permit the pathologist to exclude those epithelial abnormalities which are not a part of the spectrum of cervical neoplasia and allow him or her to place the patient with cervical neoplasia at the proper stage in the development of the process. With this information the clinician can then intelligently plan appropriate therapy.


Midtrimester pregnancy termination with prostaglandin E2 vaginal suppositories. One hundred midtrimester pregnancies were randomly selected for elective termination with 20 mg prostaglandin E2 vaginal suppositories. The abortion rate was 93%. There were 66% complete abortions, 27% incomplete abortions and 7% failures. Mean insertion abortion time was 17 hours, 26 minutes. Average dosage was 82 mg. There were no mortalities but a high percentage of side effects, all of which were well tolerated. Two patients were admitted to other hospitals unfamiliar with termination technics, transfused and subjected to dilatations and curettages. There were no long-term sequelae.


Intrauterine (extraamniotic) prostaglandins in the management of unsuccessful pregnancy. Extraamniotic administration of prostaglandin E2 or prostaglandin F2alpha has been used in the treatment of 72 cases of unsuccessful pregnancy which included 50 of fetal death in utero, 13 of anencephaly and nine of hydatidiform mole. This management is highly effective in achieving abortion or delivery within 24 hours in almost all cases and results in few side effects. Pyrexia occurred during treatment in three patients, but in none was intrauterine infection observed. Blood loss greater than 250 ml occurred in only two patients, and none required transfusion. We advocate the use of extraamniotic prostaglandins as an active approach to the problem of unsuccessful pregnancy to relieve the patient of emotional distress and avoid the hazards of blood coagulopathy and intrauterine infection, both of which increase the longer a dead fetus is retained in utero.


The use of oral prostaglandin E2 to induce labor at term. Prostaglandin E2 (PGE2) was given to 60 patients to induce labor at term. Two dosage schedules were used: 30 patients were given 0.5 mg hourly and 30 patients were given 1.0 mg hourly. Membranes were ruptured when active labor had occurred. The Bishop score was used for inducibility quotient. In general, the higher the Bishop score, the shorter the delivery time. The 1.0 mg dosage schedule decreased the induction time in both nulliparas and multiparas. There were 55 vaginal deliveries. Five patients were delivered by cesarean section for obstetrical indications; two were in active labor. The overall success rate was 91.6%. No fetal distress occurred that could be attributed to the PGE2. Maternal complications consisted of nausea and vomiting.


Classification and relationships of induced chromosomal structual changes. A detailed survey is given of the types and classification of primary structural changes that can be induced in chromosomes and observed at the first metaphase after the initial damage. Comments upon identification and scoring are given for the benefit of new workers. The annotation concludes with a brief discussion of the potential relationships between the primary types, and the secondary or derived types encountered in clinical studies.


Absence of distal interphalangeal creases of fingers with flexion limitation. An Ashkenazi Jewish family is described, in which absence of distal interphalangeal creases of fingers with flexion limitation is transmitted through 4 generations with 8 affected individuals. The malformation is caused by an autosomal dominant gene with full penetrance and variable expressivity, and causes only little inconvenience. In one case the joints were normal on radiological examination. The malformation was not associated with any other anomaly except in the propositus who was referred becaused of profound mental retardation and cerebral palsy. This association is probably fortuitous as the other affected members were of above average intelligence. We were unable to find any report on this anomaly without associated malformations.


A family of juvenile proximal spinal muscular atrophy with dominant inheritance. A family with juvenile proximal spinal muscular atrophy with dominant inheritance and complete penetrance is reported. The disease occurred in three generations and showed high variations in the age of onset and progression among the affected members. A characteristic feature was the constant involvement of facial nuclei.


Camptodactyly, with muscular hypoplasia, skeletal dysplasia, and abnormal palmar creases: Tel Hashomer camptodactyly syndrome. A syndrome characterized by camptodactyly, distinct facial features, multiple musculoskeletal defects, and unique dermatoglyphic changes is described in two sisters born of consanguineous parents. In 1972 this same constellation of findings was first reported in two sibs from a different ethnic origin. This heritable disorder of connective tissue termed the Tel Hashomer camptodactyly syndrome is thought to be transmitted as an autosomal recessive trait. The basic defect is unknown.


Haemoglobin M Hyde Park occurring as a fresh mutation: diagnostic, structural, and genetic considerations. Hb M Hyde Park disease was detected in a girl who for several years was thought to have cyanotic heart disease. The problems of recognizing the condition are outlined and clues to diagnosis are discussed. Evidence for heme loss from the aberrant beta chains of Hb M Hyde Park and production of an unstable molecule is presented. The normal haematological findings in the patient's parents, as well as their blood groups and isozymes, suggest that the occurrence of her Hb M Hyde Park was the result of a fresh mutation.


The Prader-Willi syndrome with a 15/15 translocation. Case report and review of the literature. A case, diagnosed clinically as the Prader-Willi syndrome, was shown by Giemsa banding, to have a 15/15 chromosome translocation. A review of the literature indicates that such a translocation has only been described once before, in a normal woman, but that chromosme abnormalities in the Prader-Willi syndrome most commonly involve the D group. The significance of this would be clarified by specific chromosome identification in these patients.


Trisomy 13 in a female over 5 years of age. A case of simple trisomy 13, confirmed by G-banded chromosome analysis, is reported in a Caucasian female over 5 years of age. There is no cytogenetic evidence available for mosaicism in the propositus or her parents. The patient's salient clinical features are: profound mental and motor retardation; microcephaly with trigonocephaly; ear malformations; small, sunken eyes; unusual eyebrows; cleft lip and palate; bulbar nose; coloboma iris; polydactyly; unusual dermatoglyphic patterns; large adductor thumbs; enlarged great toes; multiple capillary haemangiomas; club feet; inguinal and umbilical hernias; hyperconvexed fingernails; and seizure disorder.


Familial ureteric bud anomalies.

Familial ureteric bud anomalies. A family is described in which various renal anomalies occurred. The condition is considered to represent an autosomal dominantly inherited 'instability' of the ureteric bud.


Use of phytohaemagglutinin stimulated lymphocytes to study effects of hypoxanthine-guanine phosphoribosyltransferase (HGPRT) deficiency on polynucleotide and protein synthesis in the Lesch-Nyhan syndrome. The incorporation of [14C]thymidine and [14C]uridine into the nucleoprotein, and [14C]phenylalanine into the protein by phytohaemagglutinin (PHA) stimulated lymphocytes from a patient with the Lesch-Nyhan syndrome [hypoxanthine-guanine phosphoribosyl transferase (EC 2.4.2.8 HGPRT) deficiency] and controls, was studied over 72 hours of incubation, with and without azaserine to block de novo purine biosynthesis. No difference was observed between the values obtained for Lesch-Nyhan and control lymphocytes, when PHA-stimulated without added azaserine. The percentage reduction in the incorporation of precursors into nucleoprotein and protein after PHA stimulation in the presence of azaserine was more obvious in the lymphocytes of the patient with the Lesch-Nyhan syndrome than in the controls after the shorter incubation periods at the lower rates of synthesis. Blocking the de novo purine biosynthetic pathway, in control PHA stimulated lymphocytes, inhibited transformation, whereas loss of the purine salvage enzyme HGPRT did not have this effect. These results are compatible with the view that the brain and bone-marrow damage that occur in the Lesch-Nyhan syndrome are the result of lack of HGPRT in tissues with little de novo purine biosynthetic capability. Other tissues with both pruine biosynthetic and salvage pathways are less vulnerable to the enzyme defect. Some possible mechanisms by which HGPRT deficiency could act are discussed. We suggest that inability to increase the supply of guanylic acid (GMP) in response to a mitotic stimulus may mediate the effect of HGPRT deficiency.


Differential expression of salivary (Amy1) and pancreatic (Amy2) human amylase loci in prenatal and postnatal development. The age-dependent development of alpha-amylase expression in utero and during the first two years of life is reported. Separation of salivary and pancreatic amylase isozymes in a discontinuous buffered sheet polyacrylamide electrophoretic system, with subsequent densitometry, provides a reliable semiquantitative method of estimating the proportions of salivary and pancreatic amylases in urine and amniotic fluid samples. In the newborn the predominant amylase isozymes seen in the urine are of salivary origin. As the child ages the level of amylase in the urine rises and an increase in the proportion of pancreatic amylase isozymes occurs. Amniotic fluids of late first and early second trimester pregnancies contain salivary isozymes. None of the amniotic fluid samples examined has pancreatic amylase isozymes. These data reflect a differential development of the expression of the two amylase approaches adult levels by 16 months of age. Conversely, the salivary (Amy1) locus is expressed as early as 18 weeks of gestation and remains relatively constant with but a small increase in salivary amylase (units/ml) activity during early development, as the total amylase activity approaches adult values.


Immunogenetic factors in aetiology of pre-eclampsia/eclampsia (gestosis). The evidence that genetic and immunogenetic influences operate in the causation of pre-eclampsia/eclampsia (gestosis) is reviewed. The problems of definitive diagnosis are discussed along with the possibility of a multifactorial aetiology. The difficulties of differentiating trigger and effector mechanisms are also considered. It is concluded that there is evidence for a predisposition, probably genetic, operating in some cases, an immunogenetic mechanism in others, and chromosomal factors in a small group.


Pre-eclampsia/eclampsia in twin pregnancies. A study of 1045 twin gestations with regard to known or likely zygosity and the incidence of pre-eclampsia/eclampsia failed to reveal differences between known dizygous twins and like-sex 'presumed' and 'estimated' monozygous twins except in the 'estimated' data for multigravidae. There was a threefold increase in the incidence for twins as opposed to singleton pregnancies. These results are discussed in relation to increased conceptus-mother antigenic differences. It is suggested that the risk of gestosis in twin pregnancy involves more than a summation of that operating in two singleton pregnancies.


X-linked anhidrotic ectodermal dysplasia with some unusual features. A total of 85 members of a family in which several individuals presented with hypodontia, hypotrichosis, and hypohidrosis were examined. Of these, 77 were evaluated clinically and the results compared with those obtained in an equal number of carefully chosen controls. The main symptoms among the affected males and females involved changes in the quantity and texture of head hair and in the distrubution of body hair. More than half of the males also showed precocious baldness, and 6 of them had dyskeratosis. The average of missing teeth was 12 among men with the syndrome, but only 2 among the obligate female carriers. The sweat pore counts were lower in the two sexes (42% and 60% of the normal values, respectively), and a much higher degree of asymmetry was observed especially among the affected women. Inheritance of the syndrome seems to be the result of a dominant sex-linked gene with 78% to 87.5% penetrance in the females. Genetic data concerning anhidrotic ectodermal dysplasia are still unsatisfactory; new, more detailed studies are needed, in which special attention is given to the female carriers.


Supravalvular aortic stenosis-infantile hypercalcaemia syndrome: in vitro hypersensitivity to vitamin D2 and calcium. The incidence of cytoplasmic metachromasia has been studied in cultures of skin fibroblasts derived from 6 cases of the syndrome of supravalvular aortic stenosis, characteristic facies, and mental retardation which in many instances represents the late normocalcaemic stage of the severe form of infantile hypercalcaemia. The percentage of metachromatic cells (mean positivity 7.3%) was significantly higher than in control cultures. The addition of vitamin D2 and calcium to culture media caused a highly significant increase in metachromatic cells (mean positivity in supplemented media 16.1%) compared with a lesser increase in controls. These findings strengthen previous suggestions that there is a genetically determined hypersensitivity to vitamin D in some cases of the syndrome. A multifactorial aetiology is proposed, dependent on a variable genetic susceptibility of fetal connective tissues to a non-physiological effect of D vitamins and a variable level of maternal vitamin D nutrition.


Partial trisomy 9 with resemblance to Coffin-Siris syndrome. An infant with partial trisomy of chromosome 9 who phenotypically resembled a case of Coffin-Siris syndrome is presented.


Pure partial trisomy for long arm of chromosome 9. A case of a 4-year-old boy with trisomy of the long arm of chromosome 9 is described (46,XY, der (9), t (9;9) (q32;q12)). The trisomy is probably the result of a translocation of the long arm of the chromosome from one homologue to the other in a parental gonad. The clinical features of the child which include severe developmental retardation, bird-like facies, tapered fingers, and flexion contractures of the legs are similar to those of the few cases described of trisomy of the whole chromosome.


Pseudohermaphroditism due to XY gonadal absence syndrome. A 21-year-old phenotypic female with a 46,XY chromosome complement and gonadal absence was studied. Basal levels of plasma immunoreactive luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, and oestradiol were measured. Pituitary sensitivity and reserve was evaluated by the exogenous administration of synthetic luteinizing hormone-releasing hormone. The episodic release of gonadotrophins was assessed by measuring plasma LH and FSH in plasma samples obtained at 20-minute intervals for a 4-hour period. Endocrine gonadal function was evaluated by a stimulation test with human chorionic gonadotrophin for 3 days. The results showed: a) persistently raised plasma levels of both LH and FSH; b) a pulsatile pattern of release of both gonadotrophins and a normal pituitary response to the synthetic hypothalamic decapeptide; and c) extremely low levels of circulating testosterone and oestradiol with a lack of response to the HCG stimulus. A careful exploratory laparotomy revealed absence of uterus, Fallopian tubes, the Mullerian portion of the vagina, and gonads. No Wolffian derivatives were found. A dissociation of testosterone and the so-called Jost substance effects during early sexual development may explain the findings in this unusual abnormality. The term 'XY gonadal absence syndrome' including five types of variants to designate this condition is proposed.


Cervical vertebral fusion (Klippel-Feil) syndrome with consanguineous parents. We describe a female infant with the cervical vertebral fusion (Klippel-Feil) syndrome whom we recognized at birth because of her short neck, restriction of cervical movement, and low posterior hairline. X-ray examination showed anomalies of C1, and between C2-3 and C3-4; thus, we classified her as type II, with variable cervical fusion. At 24 months she was small and manifested hearing deficiency. The mother and father were consanguineous with five common ancestors four generations ago, which resulted in a coefficient of inbreeding equivalent to a second cousin relationship. The parents and grandparents were phenotypically normal, and the parents were radiologically normal. This form of the syndrome has previously been said to be autosomal dominant. Our conclusion of determination by a single autosomal recessive gene is evidence of genetic heterogeneity.


Pterygium syndrome.

Pterygium syndrome. The pterygium syndrome consists of the neck, the antecubital fossae and the popliteal regions together with flexion deformities of the limb joints and anomalies of the vertebrae. A family, three offspring of which appear to be affected with the same disorder, is presented. All three are female; there is also a normal female child of the same union.


Weiskotten survey, class of 1960: a profile of physician location and specialty choice. This survey is the eighth in a series which has included every fifth American medical school graduating class, starting with the class of 1915. The questionnaire design differed from previous Weiskotten studies and emphasized attitudes towards location information not contained in the American Medical Association Physician Masterfile. Traditional tabular comparisons are focused on contemporary locational policy needs. The findings and methodology of this study are generally similar to those of many earlier studies of both physician location and, in a very limited way, of specialty choice. The paper contains findings on certain characteristics of physicians who move their practice and those who do not. These characteristics have not been contrasted previously in this series.


A positive approach to the utilization of student feedback in medical education. Many of the problems related to the usability of student feedback in medical education are concerned with validity and reliability. In this paper the author presents a rationale and a systematic procedure for the construction, implementation, and analysis of student feedback data which will provide both valid and reliable information about specific areas of the educational process that are controllable by instructors. This information can then be combined with other factors and used for continuous improvement of the teaching/learning process.


A look at a deviant group of medical school applicants. A total of 246 physicians who either had graduated from or had matriculated without graduating from dental school prior to entering a medical school were identified, and a combination multiple-choice, open-ended questionnaire was mailed to the group. Completed questionnaires were recived from 194 subjects for a 79 percent response rate. The questionnaire was designed to elicit information about the decision to study dentistry and the subsequent decision to study medicine. The authors were also interested in the process of admission to medical school, in academic performance in both schools, in choice of medical specialty, and in attitudes toward dentistry and medicine.


An individualized course in clinical psychiatry. Although a variety of new teaching strategies and materials are available in education today, medical education has been slow to move away from the traditional lecture format. An individualized course in clinical psychiatry is described, both from a philosophical and operational frame of reference. Features of the course of include programmed instruction, behavioral objectives, criterion-referenced mastery level evaluations, contracting for grades, and utilization of small-group discussions. Attention is directed to the advantages of the new methods as well as to new problems which surfaced.


Trends in medical education in Great Britain. In this paper the author examines the ways in which medical school curricula have been influenced in recent years. First, consideration is given to the factors that led to the basic curriculum adopted by British medical schools at the time the National Health Service was established in Britain. Then the author goes on to examine how the founding of the National Health Service itself about a further influence on patterns in medical education and considers the effects this has had. Finally, he considers likely future development in light of present trends and assesses their implications.


A comparison of two item-scoring procedures and student reactions to them. Two scoring schemes--a partial-credit scoring scheme and a dichotomous scoring approach--were compared to determine whether one could be selected over the other on the basis of empirical data. Means, variances, and reliabilities on alternate measures and student reactions to the two approaches were analyzed. It was found that the mean partial-credit test score was significantly greater than the dichotomous test score. Reliability on the partial-credit measure was higher, but not significantly, than the dichotomously scored measure. Variance of the dichotomously scored measure was greater, but not statistically, than its partial-credit counterpart. Students clearly preferred the partial-credit approach over the dichotomous scheme. It was concluded that the partial-credit scoring system permitted the assessment of a significant amount of partial knowledge. The approach is recommended if rewarding for partial knowledge is an important concern.


Mathematical modeling and the redesign of a teaching ambulatory clinic. Mathematical modeling was utilized in the planning and decision-making process involved in reorganizing a teaching clinic to effect continuity of care. The model interrelated physicians, time and space, facilitating value judgments and decisions. After examining multiple model runs, the authors finally selected a per-clinic-session doctor mix of 5 interns, 2.3 residents, and 1.6 fellows. Group productivity by model simulation was 14.6 pts/hour, utilizing 10.1 rooms. Subsequently, 90 house officers were each assigned to the clinic one-half day a week on a continuing basis. Time-motion data, from 10 sessions five months after the change, showed that during one week 353 patients were seen at a rate of 13.9 patients per hour in the rooms and time available. The fact that the reorganization was successful and the outcomes remarkably similar to model predictions has engendered confidence in the role of modeling in the planning process.


Clostridium difficile: isolation and characteristics. Clostridium difficile can be grown readily in Reinforced Clostridial Medium (RCM) containing 0-1-0-4% of o-, m- or p-cresol, or phenol. We recommend 0-2% of phenol or p-cresol in RCM for the isolation of this organism. The characteristic "cornfield" growth in RCM in 25-ml Universal containers is described. Glucose, fructose, galactose, mannose, raffinose, aesculin and mannitol are fermented with production of acid and gas; maltose, sucrose, glycogen, soluble starch and sorbitol are fermented with production of acid only. Lactose and rice starch are not fermented by any strain, and DL-methionine is not attacked. Nitrate is reduced to nitrite. Hydrogen sulphide and indole are not produced. Gelatin is attacked by all strains, but in some cases prolonged incubation is required. Hyaluronidase is produced, but not deoxyribonuclease. A lethal toxin appears to be produced. Strains possess shared and strain-specific antigens.


The route of entry of leptospires into the kidney tubule. To study the migration of Leptospira interrogans serotype pomona through the kidney, conventionally-reared mice aged 2 or 3 weeks were infected intraperitoneally with this organism. Within the first 4 days, the organisms migrated from the capillary lumina to the interstitial tissue and provoked an interstitial oedema. By the 10th day they were seen between the epithelial cells of the proximal convoluted tubules and by the 14th day many were located within tubular lumina. There was no evidence of viable leptospires within the cells of the proximal tubules, though occasionally structures resembling leptospiral fragments inside lysosomes were observed. At no stage during the study were glomerular lesions seen.


Studies on Campylobacter sputorum subspecies Mucosalis. Catalase-negative vibrios can be isolated in large numbers from the affected intestinal mucosa of pigs suffering from a range of porcine enteropathies in which the mucosa has an adenomatous component. These vibrios cannot be distinguished from strains of Campylobacter sputorum subsp. mucosalis. The resemblance between these bacteria strengthens the case already made on morphological evidence that these enteropathies have a common origin. Catalase-negative vibrios have also been isolated from the mouth and faeces of pigs. Some of these conform to the criteria established for the mucosalis subspecies but others can be differentiated from it. An antigenic analysis shows that strains of the mucosalis subspecies are closely related antigenically, but that differences may allow separation of strains.


Lipolytic activity of Staphylococcus aureus from different sources. The lipolytic activity for a number of triglycerides, oils, and Tween 80 of 50 Staphylococcus aureus strains from the margin of the eyelids in patients with chronic blepharitis was found to be significantly greater than that of 80 S. aureus strains from the upper respiratory tract.


Calcium-binding of synaptosomes isolated from rat brain cortex. IV. Effects of ruthenium red on the Co-operative nature of calcium-binding. Ruthenium red combines with isolated synaptosomes, resulting in strong inhibition of their Ca2+-binding. In isotonic saline media, however, the dye-induced inhibition of Ca2+-binding is significantly greater than that expected for the amount of bound dye and Hill's exponent of the Ca2+-binding decreases to 1 with an increase in the amount of the dye bound. On the other hand in isotonic mannitol-sucrose solution, inhibition of synaptosmal Ca2+-binding brought about by the dye is proportional to the amount of dye bound. Based on these results, the effects of the dye on the co-operative nature of synaptosomal Ca2+-binding is discussed.


The effect of poly-L-lysine, amiloride and methyl-L-lysine on gill ion transport and permeability in the rainbow trout. The action of poly-L-lysine (PLL) on Na and Cl transport across freshwater fish gills was studied. Low concentration (10-6M) were added to the external medium for brief periods (1--5 min), then removed. During the next 20 min there was a rapid net loss of Na (117+/17 muEquiv[100 g]-1hr-1) and Cl (129+/17 muEquiv[100 g]-1hr-1). Both values are an order of magnitude larger than unidirectional effluxes in control fish. The efflux of both ions decreased to control values within 60 min after application and removal of PLL. In contrast, unidirectional influxes (JCl in and JNa in) were inhibited by about 40+ and showed no sign of returning to the original rates for 3 hr. Thus, PLL has two independent actions, causing a large increase in gill permeability which is reversible within an hour and apartial inhibition of influx which showed no sign of reversing for 2--3 hr. When PLL was applied for a longer period (60 min, the results were qualitatively similar but the permeability change was larger and persisted longer. These effects were compared with those of the small organic amines, amiloride and methyl-L-lysine. The latter inhibited JNa in, but there was not other similarity to PLL. Neither affected sodium efflux, not did they have any effect on Cl movements, in or out, across the gill. Inhibition of JNa in, was rapidly and completely reversible, and amiloride was shown to act by competing with Na for an entry site.


Modification of valinomycin-mediated bilayer membrane conductance by 4,5,6,7-tetrachloro-2-methylbenzimidazole. The compound 4,5,6,7-tetrachloro-2-methylbenzimidazole (TMB), has been found to markedly modify the steady-state valinomycin-mediated conductance of potassium (K+) ions through lipid bilayer membranes. TMB alone does not contribute significantly to membrane conductance, being electrically neutral in solution. In one of two classes of experiments (I), valinomycin is first added to the aqueous phases, then changes of membrane conductance accompanying stepwise addition of TMB to the water are measured. In a second class of experiments (II), valinomycin is added to the membrane-forming solution, followed by TMB additions to the surrounding water. In both cases membrane conductance shows an initial increase with increasing TMB concentration which is more pronounced at lower K+ ion concentration. At TMB concentrations in excess of 10(-5) M, membrane conductance becomes independent of K+ ion concentration, in contrast to the linear dependence observed at TMB concentrations below 10(-7) M. This transition is accompanied by a change of high field current-voltage characteristics from superlinear (or weakly sublinear) to a strongly sublinear form. All of these observations may be correlated by the kinetic model for carrier-mediated transport proposed by Läuger and Stark (Biochim. Biophys. Acta 211:458, 1970) from which it may be concluded that valinomycin-mediated ion transport is limited by back diffusion of the uncomplexed carrier at high TMB concentrations. Experiments of class I reveal a sharp drop of conductance at high (greater than 10(-5) M) TMB concentration, not seen in class II experiments, which is attributed to blocked entry of uncomplexed carrier from the aqueous phases. Valinomycin initially in the membrane is removed by lateral diffusion to the surrounding torus. The time dependence of this removal has been studied in a separate series of experiments, leading to a measured coefficient of lateral diffusion for valinomycin of 5 x 10(-6) cm2/sec at 25 degrees C. This value is about two orders of magnitude larger than the corresponding coefficient for transmembrane carrier diffusion, and provides further evidence for localization of valinomycin in the membrane/solution interfaces.


Studies on the brush border membrane of mouse duodenum. III. Iodination of membrane proteins. Microvillus membranes were iodinated from luminally administered lactoperoxidase, H2O2 and 125I before and after neuraminidase treatment. Membranes were isolated, solubilized in sodium dodecyl sulphate buffer and electrophoresed on gels. Gels were stained for protein, and then sliced for liquid scintillation counting. When membranes were not treated with neuraminidase, the nonpermeating iodination probe attached only to a band containing protein of 150,000 daltons approximate molecular weight. This size class of protein may reside on the luminal side of the brush border membrane as opposed to the serosol side. Qualifications of this statement are discussed with reference to the location of tyrosyl residues and to the possibilities of masking molecules. Membranes treated from the luminal side with neuraminidase to remove possibly masking carbohydrate and then iodinated, appeared to contain an additional protein of estimated molecular weight 220,000 daltons which was accessible to 125I. Thus, a 220,000 dalton protein may also be on the luminal side of the membrane. An explanation is attempted for the discrepancy between the very few proteins labelled and the many proteins involved in terminal digestion and transport which would all be expected to be available to luminally administered iodination probe. Membranes were isolated, exposed to iodination and then solubilized for electrophoresis. Nearly all proteins were labelled, which indicated that there is an asymmetric distribution of proteins in the plane of the membrane. The two smallest molecular weight polypeptides which were not iodinated were proposed to be so disposed in the membrane that they were inaccessible to the probe, from either side.


New membrane formation and intercellular communication in the early Xenopus embryo. The ionic permeability of the nonjunctional and newly formed junctional membranes was investigated in embryos of Xenopus laevis up to the onset of the fifth cleavage. Continuous measurements were made of the equivalent nonjunctional (R'o) and junctional resistances (R'i) in different pairs of adjacent cells separated by one of the four cleavage membranes formed in that period. The specific resistance of the nonjunctional membranes (ro) and of each cleavage membrane (ri) as a function of time were derived using a generally applicable computer simulation model. ro decreased from about 40 komega cm2 in the in the uncleaved egg to about 10 komega cm2 at the 16-cell stage, due to the insertion of a small fraction of the relatively permeable newly formed cleavage membranes into the outer surface. Superimposed on this overall decline, a transient decrease of ro was observed during each cycle, caused by a temporary partial separation of the peripheral parts of adjacent blastomeres. The changes in followed the same pattern. R'1 increased stepwise during each cleavage cycle. At the onset of each cleavage there were no significant differences in R'i as measured between different pairs of cells. After an initial phase of membrane formation ri of all cleavage membranes remained constant at about 400 omega cm2. In the states investigated the coupling ratio ranged from 0.8 to 1. It is argued that this close coupling could be the result of the highly impermeable outer surface even in the absence of specialized junctions in the intercellular membranes.


New membrane formation and intercellular communication in the early Xenopus embryo. II. Theoretical analysis. In conjunction with a previous analysis of the electrical networks formed by the Xenopus embryo during development from the 2-cell stage to the 16-cell stage, some theoretical aspects are investigated. A computer simulation method for the derivation of the specific membrane resistances from the measured equivalent resistances between different compartments of a multicellular biological system is described in detail. The interdependence of the equivalent junctional and nonjunctional resistances, and the possible role of the blastocoel in intercellular communication are analyzed. Assuming that no direct pathways exist between nonadjacent cells, the equivalent junctional and nonjunctional resistances, as well as the resulting coupling ratios are calculated for all pairs of cells in the 4-cell, 8-cell and 16-cell embryo. Previous studies on electrotonic coupling in the early Xenopus embryo are discussed.


Kinetic analysis of carrier-mediated ion transport by the charge-pulse technique. The charge-pulse technique has been used previously for the study of quasi-stationary processes in membranes which required only a moderate time resolution. It is shown here that a time resolution of about 400 nsec may be achieved with this technique and that it may be applied to the kinetic analysis of carrier-mediated ion transport. By this method we have studied the transport of alkali ions through optically black monoolein membranes in the presence of the ion carrier valinomycin. All three relaxation processes that are predicted by theory have been resolved. From the relaxation times and the relaxation amplitudes the rate constants for the association (kR) and the dissociation (kD) of the ion-carrier complex, as well as the translocation rate constants of the complex (kMS) and the free carrier (kS) could be obtained. For 1 M Rb+ at 25 degrees C the values are kR=3 x 10(5) M(-1) sec(-1), kD=2 x 10(5) sec (-1), kMS=3 x 10(5) sec(-1), kS=4 x 10(4) sec(-1). The activation energies of the single rate constants which have been estimated from experiments at two different temperatures range between 50 and 90kJ/mol.


Temporal and local concentration changes in diffusion layers at cellulose membranes due to concentration differences between the solutions on both sides of the membrane. By means of a laser-interferometrical method diffusion layers at the interface of a noncharged cellulose membrane are studied. These layers are induced by a concentration difference between the NaCl solutions separated by the membrane. The temporal and local shift of the NaCl concentration in the diffusion layers were measured. A steady-state concentration profile could be obtained for times of 121 sec less than or equal to to less than or equal to 484 sec. The concentration profiles at any time (to less than or equal to 900) are not a linear function of the membrane surface, but could be fitted to a quadratic function. The thickness of the diffusion layers is also a function of time and its stationary value in this system is (575 +/- 49) X 10(-6)m. The role of concentration polarization for the determination of phenomenological thermodynamic coefficients of membranes is discussed and a new method is suggested, which excludes the difficulties of the concentration polarization in the diffusion layers at the membrane.


Membrane capacity of squid giant axon during hyper- and depolarizations. The change in membrane capacitance and conductance of squid giant axons during hyper- and depolarizations was investigated. The measurements of capacitance and conductance were performed using an admittance bridge with resting, hyperpolarizaed and depolarized membranes. The duration of DC pulses is 20-40 msec and is long enough to permit the admittance measurements between 1 and 50 kHZ. The amplitudes of DC pulses were varied between 0 and 40 mV for both depolarization and hyperpolarization. Within these limited experimental conditions, we found a substantial increase in membrane capacitance with depolarization and a decrease with hyperpolarization. Our results indicate that the change in membrane capacitance will increase further if low frequencies are used with larger depolarizing pulses. The change in membrane capacitance is frequency dependent and it increases with decreasing frequencies. The analyses based on an equivalent circuit (vide infra) gives rise to a time constant of active membrane capacitance close to that of sodium currents. This result indicates that the observed capacitance changes may arise from sodium channels. A brief discussion is given on the nature of frequency-dependent membrane capacitance of nerve axons.


Pigment containing lipid vesicles. II. Interaction of valinomycin with lecithin as sensed by chlorophyll a. Valinomycin added to a suspension of chlorophyll a containing lecithin vesicles induces slight changes in the spectrum of chlorophyll a. These changes are measured as a difference spectrum between samples with and without valinomycin but of otherwise identical composition. The analysis of the experiments reveals that the effect is neither associated with the ionophoric properties of valinomycin nor due to a direct interaction of this agent with chlorophyll a. The molar ratio of valinomycin dissolved in the membrane to lecithin is found to be the relevant parameter, thus indicating an interaction between these two components. As a consequence, the aggregational state of the lecithin molecules is altered. Chlorophyll a incorporated into the membrane acts as a sensor, i.e. it reflects the alteration by a change in its spectroscopic parameters.


Studies on the brush border membrane of mouse duodenum. II. Membrane protein metabolism. Mouse duodenal microvillus membrane protein metabolism was measured using radioactive labelling techniques. Labelled amino acids were introduced into the lumen of ligatured duodena. Following exposure to label, brush border membranes were isolated and analyzed. Experiments measuring the specific activity of protein labelled with a single amino acid revealed that total membrane protein appeared to turnover in about 14 hr. Protein in the mucosal homogenate had a faster turnover rate. Turnover rates of individual proteins were measured with single and dual isotope experiments. Membrane protein was solubilized with sodium dodecyl sulphate (SDS) buffer. Single isotope experiments showed that all polypeptides separated on SDS-gels were maximally labelled at 6 hr after injection. Bands did not incorporate label linearly. Rates of loss (degradation) of label from membrane proteins in the seventeen bands appeared to be related to the estimated molecular size of the proteins. Rates were highest for larger polypeptides. A double isotope technique, in which proteins were allowed to incorporate the same amino acid in two isotopic forms, delivered with a set time interval intervening, revealed that the ratios of the second label to the first in the SDS-separated polypeptides were highest for larger proteins and lowest for smaller polypeptides. Certain assumptions were outlined and the ratios taken as measures of turnover  of proteins. Loss of label due to cell sloughing is discussed. A mixture of labelled amino acids (excluding leucine) was used to show that differences in leucine contents of different proteins was not an explanation for the variation in level of leucine radioactivity in different bands. For specific activity measurements throughout, protein in gels was quantitated with reference to the uptake of Coomassie stain. The use of this stain was validated by the finding that, at low protein concentration, the amount of stain taken up was proportional to the amount of bovine serum albumin or membrane protein loaded.


Neuronal pathways from the dorsal ocelli of the house cricket, Acheta domesticus. Each ocellar nerve in the house cricket Acheta domesticus contains giant nerve fibers of 10--15 mum diameter, characterized in Golgi-Cox preparations by a single row of short collaterals which runs along nearly the entire length of a fiber. Numerous long collaterals are given off by thin fibers in the ocellar nerve; medium-size fibers give off relatively few collaterals. The lateral ocellar tracts extend posteriorly through the dorsal protocerebrum, crossing the protocerebral bridge dorsally. The smaller median ocellar tract runs more ventrally through the pars intercerebralis; posterior to the bridge its fibers turn out toward the lateral nerves. Golgi and cobalt preparations reveal branching of giant and medium-size ocellar fibers posterior to the bridge at two levels, forming bilateral regions of ocellar neuropile. No ocellar processes appear to be given off to the corpora pedunculata, central body, nervi corporis cardiaci, antennal lobes, or circumesophageal connectives; it is uncertain whether ocellar collaterals extend into the protocerebral bridge or optic lobes. Cell bodies of giant and medium-sized fibers are located in the pars intercerebralis.


Collagenous and other organizations in mature annelid cuticle and epidermis. The mature annelid cuticle contains orthogonally oriented collagen in a matrix capped superficially by a dense epicuticle with external corpuscles. The underlying epidermis is a simple columnar epithelium with two major cell types, mucous-secreting cells which secrete through channels in the cuticle to the exterior of the worm, and "supportive" cells which presumably produce and increase the cuticle by secreting into it. The structures of supportive cells, previously interpreted as specialized for establishing interfibrillar collagen order, are revealed by glutaraldehyde fixation as common cellular components without the qualities deemed useful to align collagen. Cell processes which penetrate and sometimes pass completely through the cuticle are not stable, not in geometric order, and lack cilia-like structure. Cilia, unlike the ubiquitous cellular processes, are highly restricted to regions of the epidermis with specialized functions. Cellular control, or other control, of collagen fibrillogenesis remains unestablished.


Collagen deposition on a preformed grid. Appearance of collagen fibrils in the cuticle was seen by electron microscopy to be preceded by formation of a finely filamentous matrix material. At first, the fine filaments of the matrix are unorganized. However, signs of orthogonal ordering soon appear in the most superficial portion of the cuticle, and subsequently appear more basally and closer to the underlying epidermis. Meanwhile, fibrils of different staining properties and identifiable as collagen begin to be deposited in the superficial portion of the cuticle, the same region which first showed organized fine filaments. Then, like the fine filaments before them, the collagen fibrils polymerize more basally. Collagen appears to polymerize on the preformed skeleton of fine filaments as though the fine filaments lagen fibrils seems to require direct cellular intervention but occur first in that portion of the cuticle which is furthest away from the underlying epidermis. The fine filaments may be self ordering, extracellular macromolecules which in turn determine the polymerization of collagen fibrils.


Morphology of the gills of larval and parasitic adult sea lamprey, Petromyzon marinus L. The general morphology of the gills is similar in larval (ammocoetes) and parasitic adult sea lampreys, Petromyzon marinus, despite different methods of ventilation necessitated by their feeding habits. The gill lamellae are supported by randomly-distributed pillar cells which enclose blood spaces and collagen columns. The distribution of these cells in lampreys is different from that of higher fishes and it may be inefficient for respiratory exchange. The presence of cytoplasmic microfilaments suggests that these cells have the ability to reduce the lamellar blood spaces through contraction. Marginal channels at the tips of the lamellae are lined only by endothelial cells. The thickness of the water-blood pathway in lampreys falls within the range described for higher fishes, with the most efficient gas exchange likely occuring at the lamellar tips where only a single layer of epithelial cells is present. The abrupt increase in height of the epithelium near the lamellar bases in adults, compared to the gradual transition in height along the lamellae in ammocoetes, is perhaps reflective of higher oxygen requirements during the parasitic stage. The consistent appearance of wide, lateral intercellular spaces within the respiratory epithelium of lampreys indicates possible involvement of these spaces in transport. Mucous secretion appears to be an important function of the superficial platelet cells in ammocoetes. "Mitochondria-rich" and "mitochondria-poor" superficial cells are observed in both ammocoetes and adults, with the mitochondria-rich cells more prevalent toward the lamellar bases. The possibility that at least some of these cells may be involved in absorption is discussed. Mitochondria-rich cells in the interlamellar region are morphologically different in ammocoetes and adults but all possess an abundance of smooth endoplasmic reticulum and hence resemble "chloride cells" of higher fishes. The similarity of these cells in the parasitic adult lamprey to chloride cells of marine fishes may reflect the potential of the adult lamprey to osmoregulate in salt water. A scarcity of these cells in ammocoetes and their resemblance to chloride cells in freshwater fishes may reflect the restriction of larval lampreys to a freshwater habitat.


The nature and development of sex attractant specificity in cockroaches of the genus Periplaneta. I. Sexual dimorphism in the distribution of antennal sense organs in five species. Sexual dimorphism in the distribution of antennal sense organs is common among adults of the genus Periplaneta. In three out of the four strains of Periplaneta americana examined, adult males had more contact chemoreceptros than females. In the fourth strain of P. americana and in P. australasiae, P. brunnea, P. fuliginosa, and P. japonica, no statistically supportable sexual dimorphism of contact chemoreceptors was found. However, in all strains and species of Periplaneta examined, sexual dimorphism was found in the total number and/or density of olfactory sensilla. Male adults had nearly twice as many olfactory sensilla as female adults. These observations are consistent with the behavioral observation that males within the genus Periplaneta rely on the reception of an airborne pheromone for the initiation of courtship behavior. In P. americana, where sexual dimorphism was found in the contact chemoreceptors, contact stimuli release the full wing raising display and presentation in males during courtship.


The cranial arteries of turtles and their evolutionary significance. In this paper the cranial arteries, cranial arterial foramina, and bony canals of the Cheloniidae, Chelydridae, Pelomedusidae, and Chelidae are described in detail. From skull studies and published material, the general cranial arterial patterns of all the turtle families can be inferred. Sea turtles, the Cheloniidae and Dermochelyidae, possess both a large stapedial artery and a large artery supplying the orbit, which is possibly similar to the primitive cranial arterial pattern for turtles. From a primitive pattern in which stapedial and palatine arteries supply the orbit, the Chelydridae and Testudinidae retained a large stapedial artery and reduced the palatine artery, while the Kinosternidae and Dermatemydidae developed a large palatine artery and reduced the stapedial artery. The Trionychidae and probably the Carettochelyidae evolved a complex arterial pattern in which the stapedial artery was reduced somewhat and the pseudopalatine artery was substituted for the palatine artery. Pleurodires in general retained a large stapedial artery and reduced or eliminated the palatine artery. The Podocneminae, including the Madagascar species, developed a highly modified carotid canal, which is found in no other turtle group. The facts which have been presented should aid in fossil skull studies and in understanding the evolutionary background of recent turtles.


Ultrastructure of the main excretory duct of the cat submandibular gland. The main excretory ducts (MED's) from the submandibular gland of adult cats were examined by electron microscopy. The ducts consisted of a pseudostratified epithelial lining surrounded by abundant connective tissue and numerous, small, longitudinally-oriented blood vessels. The taller epithelial cells were closely coherent, without the luminal clefts between adjacent cells that are characteristic of rat MED's. In the cat, these cells lacked basal membrane specialization, but showed considerable lateral interdigitation. Some microvilli were present on the apical surface. In a few rare cells, the luminal surface bore cilia of typical appearance. The smaller, pyramidal basal cells had irregular basal surfaces that gave rise to one or more long cytoplasmic processes. The basal surface of the pyramidal cells was studded with hemidesmosomes. The cytoplasms contained abundant tonofilaments, which sometimes aggregated in prominent perinuclear bundles. Occasional goblet cells were present in the duct wall. MED's perfused either in situ or in a perfusion chamber with Locke's solution also were studied. Even after perfusion of 160 minutes duration, the ultrastructure of the ductal epithelium showed remarkably few alterations. The MED model system thus remains stable long enough to carry out physiological experiments which may produce ultrastructural alterations.


The structure and formation of the byssus attachment plaque in Mytilus. The byssus attachment plaque and the tissues responsible for its formation were studied in M. californianus by light microscopy and by transmission and scanning electron microscopy. It was shown that the plaque consists of at least three phases which ultrastructurally resemble three secretions considered to be collagen, mucoid material and polyphenol. The mucoid and polyphenol appear to mix as a colloidal suspension in which the latter is the continuous phase and forms the definitive bonding surface. Plaque collagen represents an extension of thread material into the cementing substance. Stimulated secretion within the ducts and distal depression of the mussel's foot shows a continuum of increasing heterogeneity from the inner toward the outer regions. This reflects the distribution of exocrine cell apices wherein exocytosis of polyphenol granules predominate deeply, mucous granules superficially and collagen granules in between. It is proposed that the morphology of the plaque conforms to theoretical physical-chemical requirements for adhesion under water.


Evolutionary processes and evolutionary noise at the molecular level. I. Functional density in proteins. The distinction between molecular sites that mainly carry out general functions and sites committed to specific functions is analyzed, notably in terms of different evolutionary variabilities. Functional density is defined as the proportion of sites involved in specific functions. Weighted functional density, by representing the relative variability at specific-function sites is to some extent a measure of the specificity of molecular interactions. The relationship between general- and specific-function sites on the one hand the covarions of Fitch on the other is discussed. The functional "degeneracy" of amino acids is described as increasing the interdependence of general functions. It is predicted that proteins tht do not possess general-function sites besides their specific-function sites tend to "freeze" their primary structure, according to an evolutionary process that is an autocatalytic function of the decrease in site variability. This limits the use of weighted functional density as an indicator of the overall degree of interaction specificity of a protein to values that are not close to unity.


Counter-examples to a neutralist hypothesis. Specific counter-examples are derived theoretically to the hypothesis that a random amino acid composition signifies a random evolutionary process.


On certain homologies between proteins.

On certain homologies between proteins. Using, in part, comparisons between reconstructed ancestral sequences, homologies are suggested between certain proteins. Genetically related groups seem to be: 1. pancreatic and bacterial nucleases, 2. lysozymes and subtilisins, 3. c type cytochromes, ferredoxins and rubredoxins, 4. b type cytochromes, myoglobins and hemoglobins, catalase, and glutamic dehydrogenase. These homologies suggest that a given ancestral sequence can evolve into quite different tertiary structures.


Polymerization of nucleotide analogues I: reaction of nucleoside 5'-phosphorimidazolides with 2'-amino-2'-deoxyuridine. 2'-Amino-2'-deoxyuridine reacts efficiently with nucleoside 5'-phosphorimidazolides in aqueous solution. The dinucleoside monophosphate analogues were obtained in yields exceeding 80% under conditions in which little reaction occurs with the natural nucleosides. In a similar way, the 5'-phosphorimidazolide of 2'-amino-2'-deoxyuridine undergoes self-condensation in aqueous solution to give a complex mixture of oligomers. The phosphoramidate bond in the dinucleoside monophosphate analogues is stable for several days at room temperature and pH 7. The mechanisms of their hydrolysis under acidic and alkaline conditions are described.


5-Methylcytosine content in the vertebrate deoxyribonucleic acids: species specificity. RNA-free native DNA samples, isolated by four methods, from different vertebrate tissues and species, were hydrolyzed chemically and enzymatically and analyzed by paper chromatography to estimate the base composition. It was noted that (i) all the DNA preparations analyzed contained 5-methylcytosine, (ii) on the basis of mole percent of 5-methylcytosine, the composition of DNA varied in different species, but not so much in different tissues of the same species, (iii) the method of DNA hydrolysis, but not the method of deproteinization, affected the mole percent of 5-methylcytosine, and (iv) no 5-hydroxymethylcytosine (5-HMC) was detected in any of the DNA preparations analyzed.


Regional transport of phenylalanine across the blood-brain barrier. In adult rats, using the single-pass brain uptake technique with a tritiated water standard, L-phenylalanine was shown to enter brain across the blood-brain barrier (BBB) by both a saturable and diffusionary process. A kinetic analysis of the data revealed a Michaelis constant (Ka) of 0.42 mM and a Vmax of 35 nmoles g-1 min-1. The saturable component of L-phenylalanine transport was adversely affected by dinitrophenol or or low sodium concentration in the intracarotid injection solution. Intravascular ouabain did not affect transport and only partial inhibition was observed with 1.5 mM L-leucine. It appears that there is no reginonal difference in the capacity of the BBB to move L-phenylalanine from blood to brain. This process is directly or indirectly coupled to sodium movement and is partially dependent on cellular energy.


Bioelectric observations on adult and newborn hypothalamic dendrites. Bioelectric activities of hypothalamic dendrites of newborn kittens and adult cats were recorded in vivo. Stimulation of various hypothalamic areas with electrical stimuli, or by injection of norepinephrine, generated propagated spikes in both newborn and adult neurons. The morphologically immature hypothalamic dendrites were hypersensitive to stimuli and were able to generate propagated spikes not only of axon hillock (adults) but also of dendritic membrane origin. Some mechanisms responsible for the two types of spike formation (newborn and adult) have been identified.


Effects of specific brain lesions on the thermal responses of rats to D-amphetamine. Lesions in either olfactory bulb or in area postrema modify the amphetamine-induced paradoxical thermoregulatory behavior, although these lesions in no way affect amphetamine-induced hypothermia. In addition, these lesions lead to complicated patterns of thermoregulatory behavior. These results can be best explained by assuming that lesions in one part of the brain monoamine system might affect levels and turnover of monoamines in remote parts of the brain. Among d-amphetamine behavioral effects which are known to be mediated by central dopaminergic neurons are hypothermia in animals placed in a cold environment, and paradoxical thermoregulatory behavior (this involves the movement of animals away from the heating source despite hypothermia). This latter effect requires intact alpha norepinephrine receptors. It seems that neither type of lesion affected dopaminergic neuronal activity in the brain. However, norepinephrine activity in the brain was affected by the area postrema lesion as well as by the olfactory bulb removal.


The effect of alpha-melanocyte stimulating hormone (alpha-msh) on the metabolism of biogenic amines in the rat brain. The effect of the chronic administration of alpha-MSH on the incorporation of tritiated tyrosine into noradrenalin and dopamine and of tritiated tryptophan into serotonin was studied in different regions of the rat brain. Alpha-MSH increased the incorporation of tritiated trytophan into serotonin in the cortex and slightly decreased that of tryosine into the dopamine in the hypothalamus. As the brain concentration of serotonin was unchanged in the animals treated with alpha-MSH, it is suggested that some of the changes in behavior, which other investigators have found following the administration of peptides containing the same sequence of amino acids to that found in MSH, could be associated with an increased turnover of cortical serotonin.


Mesencephalic lesions followed by normophagia but decreased body weight. Twenty mature male Sprague-Dawley rats were lesioned in the area of the ascending ventral noradrenergic bundle in the mesencephalon. Nine sham-operated animals served as controls. Food intake between the lesioned and nonlesioned groups was not significantly different except for the first day post surgery. However, body weight of the lesioned group was significantly below that of the controls when measured 15 days after the operation. The lesioned animals weighed significantly less than the controls throughout the rest of the  experiment. They also were hypoactive when compared to the sham-operated rats. Control rats and lesioned rats did not differ significantly in deep rectal temperature. It is suggested that the significant decrease in body weight of the lesioned rats in the presence of normophagia may be caused by alterations in the animal's metabolism.