Biomedical subjects
Publications and source records attributed to A Robert.
Seven distinct periods may be recognised during ovarioles development. The timing of events is different in each species. In Roscius elongatus the first oocytes appear by the end of the fourth larval instar. In Roscius brazzavilliensis the meiosis starts later, in the middle of the fifth instar.
An assay (enteropooling assay) to test the diarrheogenic property of prostaglandins is described. Fasted rats are given a prostaglandins either orally or subcutaneously, and are killed 30 min later. The entire small intestine is removed and its contents collected into a test tube. The greater the volume of this intestinal fluid, the more diarrheogenic is the prostaglandin. The assay is simple, rapid, quantitative, and predictive of diarrhea. It can be used to grade the relative diarrhoegenic activity of prostaglandins as well as to test agents that may block this effect. The accumulation of fluid into the small intestine is called "enteropooling". It is the sum of (a) the fluid being excreted from the blood into the lumen, and (b) to a lesser extent, the portion of fluid already into the lumen but whose absorption is inhibited by the prostaglandin. The degree of enteropooling depends also on how much fluid flows from the small to the large intestine. Our results support the hypothesis that the diarrhea observed after administration of high doses of prostaglandins is due to accumulation of abundant fluid into the small intestine, and not intestinal hypermotility. This fluid is then carried into the large intestine and eventually expelled as diarrhea. Agents other than prostaglandins were tested for enteropooling activity. Laxatives such as castor oil, hypertonic solutions and bile salts caused enteropooling.
An arterial line filter can become a grave source of platelet and fibrin destruction, with widespread deposition on the filter to form a membrane across the mesh, as proved by careful scanning electron microscopy. The same filter, when subjected to the low flows of the cardiotomy line, was well tolerated and served a very useful function. There was a 260% improvement in platelet counts and a 170% reduction in chest drainage when the arterial line filter was not used, perhaps through elimination of a degree of consumptive coagulopathy. Neurological changes did not occur in the absence of the arterial line filter, and operative mortality was 4.8% (5 of 103 patients).
Testosterone and androstenedione concentrations in the plasma and testis of male guinea-pigs were estimated by gas chromatography at intervals (36 stages) from birth to death. Four main periods of androgenic activity were recognized. The neonatal period, from birth to Day 16, is characterized by a precocious but transient peak in plasma testosterone concentration at Days 2 and 3. The pubertal period from Days 16 to 90 can be subdivided into a prepubertal period starting on Day 16 and marked by a sudden linear increase in plasma and testicular testosterone concentration together with an increase in testicular and seminal vesicle weight, and a postpubertal period, from Day 50 (the time of hormonal puberty) to Day 90, characterized by high and stable androgen levels while testicular and genital tract development continues. Adulthood spans the period between Months 3-6 and Month 24; plasma and testicular concentrations of testosterone and androstenedione are stable but lower than those observed during puberty. The period of senescence occurs between Months 24 and 28 and is marked by a fall in testosterone secretion and involution of the seminiferous tubules and accessory sex glands.
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Six patients undergoing major elective vascular operations received an average of 1,700 ml. of intraoperative autotransfusion of shed blood. The patients were anticoagulated systemically during operation. The mean platelet count (156,000 per cubic millimeter and fibrinogen value (257 mg. per 100 ml.) were normal in autotransfused blood and the mean hemoglobin level was slightly below normal (11.5 Gm. per 100 ml.). Plasma hemoglobin values were variable. No patient suffered any complication that could be attributed to autotransfusion. Donor blood transfusion was avoided in five of the six patients by salvage and reinfusion of shed blood. No evidence of coagulopathy was found in any patient as measured by platelet count, fibrinogen level, prothrombin time, partial thromboplastin time, euglobulin clot lysis, and fibrin degradation products. The technique of intraoperative autotransfusion is described in detail.
Effects of a synthetic prostaglandin analog-16--16-dimethyl prostaglandin E2, methyl ester (16-diMe-PGE2)--on pancreatic secretion were evaluated in seven dogs with chronic duodenal fistulas. Graded doses of 16-diMe-PGE2 were administered intravenously (0.1, 0.3, 0.5, and 1.0 mug per kilogram, intraduodenally, or intragastrically (15, 30, 50, 100 mug per kilogram) with the pancreas in the resting state or in response to (1) secretin and (2) secretin with cholecystokinin-pancreozymin. Profound and prolonged inhibition of volume and bicarbonate concentration of secretion occurred in the resting and stimulated gland. ED50 was 0.31 mug per kilogram intravenously (1/75 the ED50 for PGE1) and 25 mug per kilogram intraduodenally. As with PGE1, stimulation of enzymes occurred, even with doses that were subthreshold for inhibition of volume and HCO3. Like PGE1, 16-diMe-PGE2 has a dual action on the intact canine pancreas (stimulation of enzymes and inhibition of volume and electrolytes), but is much more potent, has a prolonged action, and is active intraduodenally and intragastrically. Nonsteroid inhibitors of endogenous prostaglandin synthesis did not alter these effects.
15-Methyl PGE2 and 16,16-dimethyl PGE2 were found (1) to be 40 and 100 times, respectively, more potent than PGE2 after intravenous administration in inhibiting histamine-stimulated gastric secretion in dogs with a denervated (Heidenhain) gastric pouch, (2) to be active orally and intrajejunally, whereas PGE2 was inactive, and (3) to exert antisecretory activity for longer duration than PGE2. 16,16-Dimethyl PGE2 was about 2.5 times more potent than 15-methyl PGE2. Volume, acid concentration, and output, and pepsin output (but not concentration) were reduced in a dose-dependent manner. In the rat, 16,16-dimethyl PGE2 also inhibited gastric secretion and prevented the formation of ulcers produced by various methods: gastric ulcers (Shay, and steroid induced) and duodenal ulcers (secretogogue induced). In this species, 1l816-dimethyl PGE2 was 2 to 50 times more potent than PGE2, depending on the endpoint, and was active orally. These prostaglandins appear to inhibit gastric acid secretion by acting directly on the parietal cells, and making these unresponsive to most stimulants. Vomiting was a side effect of the prostaglandin analogues in the dog, but almost exclusively when these were given orally. After intravenous or intrajejunal administration at doses inhibiting gastric secretion by 80%, vomiting was seen only once. These results suggest that 15-methyl PGE2 and 16,16-dimethyl PGE2 may be of value in the treatment of peptic ulcer.
In 32 healthy male volunteers the effects on gastric secretion of three methyl analogues of prostaglandin (PG) E2 have been studied, namel, 15 (R) -15-methyl PGE2 methyl ester, 15 (S) -15-methyl PGE2 methyl ester, and 16, 16-dimethyl PGE2. Secretion was measured for 30 min and a PG analogue at doses ranging from 1.25 to 2.5 mug per kg or a placebo was administered. Gastric secretion was then stimulated either by an intravenous infusion of pentagastrin (2 mug per kg-hr) or by a peptone meal with acid secretion determined by intragastric titration technique. The tests were randomized and double blind. All three methyl PG analogues exhibited a profound and prolonged inhibitory action on gastric acid and pepsin secretion induced by pentagastrin. PG analogues caused almost complete inhibition of gastric acid response to a peptone meal accompanied by a significant reduction in the serum concentration of immunoassayable gastrin. Except with the highest dose of PG (S) -15-methyl PGE2 methyl ester, which caused abdominal discomfort and single episodes of diarrhea in some subjects, no symptoms or untoward biochemical effects were observed. It is concluded that these methylated PG analogues are very potent inhibitors of gastric acid and pepsin secretion stimulated by pentagastrin or a meal and may have clinical potential in the treatment of peptic ulcer.
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The authors studied cerebrospinal fluid (CSF) in 51 patients with malignant blood diseases. 136 assays were performed over a three month period. In children, two technics were used; in the first case, smears were done with cells obtained through centrifugation; in the second case, CSF was directly thrown on glass slides in a special cytocentrifuge. Only the latter was performed for adults. In each case, the results of the cytological analysis were compared with those of cyto-chemical assay and clinical status.
In male Guinea-pig, hormonal puberty is situated about the 50th day; at this moment production rate of testosterone reaches its maximum during post-natal life. This hormonal puberty period is preceded by a prepuberty period, marked by a sharp linear increase of plasmatic and testicular testosterone levels, which starts on the 16th day, long before spermatozoïds became apparent.
During courses of haemodialysis or treatment with powerful diuretics, the clinician at the present time bases his actions on blood pressure levels which reflects blood volume and on weight variation which is dependent on water loss. The authors show, in studying variations in total body impedance at 5kHz and 1kHz and their ratio R, that there exists another method of observation which complements the basic notions provided by blood pressure levels and baseline weight. They were thus able to detect the possible formation of cellular oedema due to excessively rapid osmotic depletion. The method makes possible the evaluation of these sectorial fluid transfers when they occur, even though they are not evident clinically. This easy to use method is perhaps less rapid than the usual means of observation but is nevertheless more rational and provides information on electrolyte balance.
With careful refinements in the pump oxygenator and a nonblood prime, bloodless open heart surgery may be performed almost routinely. In our series these measures reduced blood trauma, with a remarkable preservation of blood elements, especially platelets, and a corresponding elimination of postoperative bleeding. The mean hematocrit value decreased from 38 to 27% and recovered to 33% in the first 3 hours of postoperative diuresis. Mannitol and furosemide were rarely needed. Of 61 adult patients whp underwent open heart surgery for aortocoronary bypass or valve replacement, the last 43 had a bloodless procedure. Of the 43, 26 (60%) required no bank blood postoperatively (in the operating room or the intensive care unit). In these 26 the operative mortality was 4% (1 patient). Bloodless techniques are invaluable during periods of bank blood shortage. They avoid the dangers of hepatitis and transfusion reaction, and they may minimize the incidence of postperfusion lung syndrome as well as renal complications.
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Gastric juice was collected from gastric pouches in dogs stimulated with histamine. 15(R)-15-methyl PGE2, methyl ester inhibited gastric secretion in dogs when given orally, but was almost inactive when given intravenously, whereas 15(S)-15-methyl PGE2 methyl ester was active by both routes. When given directly into the small intestine (intrajejunally), the 15(S) was active and the 15(R) was inactive. The 15(R), diluted in acid and administered intrajejunally, became active in inhibiting gastric secretion. When the 15(S) was diluted in acid and administered intrajejunally, it lost half of its activity. When each analog was incubated in an acid medium, each was epimerized to give approximately a 1:1 mixture of both 15(R) and 15(S). Incubation of the 15(R) in pH 3 buffer resulted in only a trace of formation of 15(S). These results explain why the 15(R) is active orally but not intrajejunally. When given orally, the low pH of gastric secretion epimerizes much of the 15(R) into the 15(S),which is active by any route. The degree of acidity of gastric contents may determine whether the 15(R) will exert an antisecretory effect.
Several prostaglandins were found to prevent development of multiple ulcertions of the small intestine, produced in rats by nonsteroidal antiinflammatory compounds such as indomethacin. The syndrome appears to be due to a prostaglandin deficiency produced by indomethacin; treatment with a prostaglandin prevents such deficiency and thus protects the animals.
A 7 week old infant was admitted for auto-immune hemolytic anemia, of progressive onset. Auto-antibodies were of IgG nature and of anti-e and anti-nl specificity. Treatment associated transfusions of leukocyte-free blood and corticosteroids reaching 4,5 mg/kg/day. Hemolysis stopped after 15 days and corticosteroid therapy was stopped without incident over 30 days. One month later, the clinical status was excellent, blood count was normal and immuno-hematological tests were negative. This case is a new one of the few auto-immune hemolytic anemias in children under 3 months of age. All showed an adequate immune development allowing the typical clinical and biological picture of an auto-immune disease, in spite of the classical idea of immunological immaturity, at this age.