Pollen: evidence and controversy.
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Chemical Warfare↗
Biomedical subjects
H Cohen
Publications and source records attributed to H Cohen.
Control of the activity of phosphoenolpyruvate carboxykinase and the level of its mRNA in livers of newborn rats. Effect of diabetes, glucose load and glucocorticoids.
Streptozotocin treatment produces a typical experimental diabetes in neonates exhibiting hyperglycemia, glucosuria, ketonemia and increased level of fatty acids in the blood. The liver is affected as well, with reduced activity of glycogen synthase and a corresponding decrease in the content of liver glycogen. In contrast, the activity of liver cytosolic phosphoenolpyruvate carboxykinase and the level of its mRNA are not affected. Using a cDNA containing P-pyruvate carboxykinase sequence, the relative abundance of the enzyme mRNA was estimated. The level of the mRNA was readily observed increasing by glucocorticoid treatment or decreasing in response to administered load of glucose. These parallel the changes observed in the activity of the enzyme under these treatments, indicating that the level of P-pyruvate carboxykinase mRNA actually determines that of the enzyme. The failure of diabetes to increase the level of enzyme mRNA and the limited response to glucose loading strongly suggest that the mechanisms controlling the level of P-pyruvate carboxykinase mRNA in neonates are relatively resistant to insulin. This is unique to neonates, since in both the adult and the fetal liver. P-pyruvate carboxykinase readily responds to insulin. The minimal levels of glucocorticoids characteristic of neonates may be associated with this phenomenon.
Animals↗
The role of the tissue adhesive fibrin seal (FS) in esophageal anastomoses.
Following surgical removal of esophageal tumors, leakage and mediastinitis is a frequent and often fatal complication. A new method has been developed to seal suture lines in the esophagus with preparations containing fibrinogen, cold insoluble globulin, factor XIII, antiplasmin, platelet growth factor, thrombin, and calcium chloride. In experimental animals operated on by standard methods, esophageal leakage developed in 50% of the animals and death in 40%. By contrast, in treated animals, esophageal leak and death developed in only 20%. More adhesions were found in treated animals than in control animals.
Animals↗
Unresponsiveness of prolactin to repeated injection of sulpiride in man.
The prolactin (PRL) response to repeated injections of sulpiride, a dopamine antagonist, was evaluated in 18 healthy young men. Each subject received one or two injections of sulpiride 1 mg/kg i.m. The first injection was always given at 9 a.m. and the second after 2, 8, 24 or 48 h. Blood samples were taken through an indwelling venous catheter every 20 min during the first hour following the injection and then hourly for 12 h. The first sulpiride injection increased serum PRL level 10-fold the peak being reached after 20 or 40 min. The second injection up to 24 h had no effect on serum PRL, but when two sulpiride injections were given at a 48 h-interval, both caused a sharp increase in PRL. To conclude, PRL cells in man, after a sulpiride injection, may therefore be unresponsive to a second sulpiride injection for more than 24 h.
Adult↗
Micrognathia-prenatal ultrasonographic diagnosis.
The first case of prenatal real-time ultrasonographic diagnosis of micrognathia is presented. Diagnosis was made at 17 weeks' gestation in the fetus of a patient with previous infant affected with the syndrome of thrombocytopenia with absent radii (TAR). Recognition of micrognathia as a part of TAR syndrome and the easy visualization of fetal facial bones in the second trimester made diagnosis possible.
Adult↗
Cytogenetic findings in congenital leukemia: case report and review of the literature.
The cytogenetic findings in a five-week-old female infant with acute lymphoblastic leukemia (ALL) are reported. Markers 11q - and 19 + were observed and considered to be due to an interstitial deletion of segment 11q13 to 11q23 of chromosome #11 and an insertion of this segment into the terminal region of the short arm of #19. Previously published banded cases of leukemic infants under one year of age have been summarized. A review of the data in these 29 cases suggests that the appearance of a normal karyotype in acute leukemia of infants (less than or equal to 1 year old) is much less common than in other categories of acute leukemia. Fourteen out of 29 cases (48%) had chromosomal abnormalities involving 11q. Seven of eight ALL cases had aberrations with a breakpoint at 11q22-23; six cases had t(4;11), one case had a del(11q) and ins(19p), and another had a t(1;22;4). All of three AMMoL cases had translocations involving the long arm of #11. The percentage of patients with t(4;11) and certain translocations involving 11q in infants with ALL or AMMoL, respectively, is higher than that seen in ALL and AMMoL in general. Eleven out of 12 cases (92%) of infant acute leukemias with chromosomal abnormalities involving 11q22-23 were five months old or less.
Chromosome Deletion↗
Selenium deficiency with total parenteral nutrition: reversal of biochemical and functional abnormalities by selenium supplementation: a case report.
A patient with multiple intestinal fistulae maintained on total parenteral nutrition for 18 months developed low serum selenium. Erythrocyte glutathione peroxidase activity was 6% of normal. Erythrocytes were not able to metabolize H2O2 as well as those from controls, although the hexose monophosphate shunt itself was intact. Granulocytes from this patient had 15% of the erythrocyte glutathione peroxidase activity found in normals. Patient granulocytes were not able to metabolize H2O2 as well as controls, although the hexose monophosphate shunt was intact. Erythrocyte glutathione peroxidase-deficient granulocytes incubated with a respiratory burst stimulant, phorbol myristate acetate, had only 60% of the hexose monophosphate shunt activity present in control granulocytes. These abnormalities were reversed with selenium supplementation. Bacterial killing of Staphylococcus aureus 502A and cardiac function were not affected by selenium deficiency. Thus, selenium deficiency resulted in biochemical and functional abnormalities of erythrocytes and granulocytes. These abnormalities were reversed with selenium supplementation.
Adult↗
Disseminated histoplasmosis complicating bone marrow transplantation.
A patient receiving allogeneic bone marrow transplant for treatment of acute myelomonocytic leukemia died on the 78th post-transplant day with clinically unrecognized disseminated histoplasmosis. Granulomas and Histoplasma organisms were found in the histologic sections of the marrow aspirate. Patients from endemic areas referred to transplant centers may be at high risk for disseminated histoplasmosis when treated with long-term prednisone for graft-versus-host disease. Aspiration of bone marrow with use of clot sections is a minimally invasive, sensitive, and rapid means of detecting granulomatous infection in such febrile immunosuppressed hosts. Disseminated histoplasmosis has not been described previously as a complication of bone marrow transplantation.
Adult↗
A new hypoprolactinemic rat strain. Prolactin, luteinizing hormone, follicle-stimulating hormone, testosterone and corticosterone levels in males and effects of two anesthetics.
A new strain of rat, the IPL nude rat, derived by spontaneous mutation from the Sprague-Dawley strain, is characterized by a lack of hair, delayed puberty and a total lack of lactation. To characterize partially the endocrine system in this rat, serum levels of prolactin (Prl), luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone and corticosterone were quantified. The content of gonadotropins and Prl in the pituitary gland was also measured. Blood samples were collected following decapitation or by cardiac puncture after ether or ketamine anesthesia. Serum levels of Prl were decreased by approximately 50% in IPL nude compared to normal Sprague-Dawley rats, regardless of the method used for collection of the samples. There were also significantly reduced levels of testosterone, LH and FSH in the serum collected from IPL nude rats. Levels of corticosterone in serum were similar in IPL nude and normal rats. There was the same relative response to anesthesia in the levels of all the hormones measured when the data from IPL nude and normal rats were compared. The quantities of LH, FSH and Prl contained in the pituitary of the IPL nude rats were not significantly different from those observed in normal rats. These data suggest that the serum hormone deficiencies observed in the nude IPL rat may be due to an altered regulation of hormone production by hypothalamic factors.
Anesthetics↗
Intracellular localization of Neurospora crassa endo-exonuclease and its putative precursor.
Endo-exonuclease of rapidly growing mycelia of Neurospora crassa was found to be distributed in a ratio of about 1.6:1 in vacuoles and in mitochondria where it is associated with the inner membrane. Although the activity in vacuoles was readily released by osmotic shock, very little of that in mitochondria was released by this method. The mitochondrial activity was partially (60 to 70%) released by sonication, and the remaining activity was solubilized in the presence of Triton X-100. An inactive form of endo-exonuclease, activated in vitro by treatment with trypsin, is present in mycelia at a level over four times that of active enzyme. It was found to be distributed in a ratio of about 2.5:1 in the cytosol and in the inner membrane of mitochondria. The mitochondrial protein was more tightly bound than the active enzyme. Very little of the inactive enzyme was released by sonication, but it was solubilized in the presence of Triton X-100. The intracellular distribution of active and inactive forms of endo-exonuclease differs in a mutagen-sensitive mutant of Neurospora crassa (uvs-3) which shows many pleiotropic effects. The most striking difference in distribution is in the mitochondria where endo-exonuclease is present almost entirely in the inactive form at a level 30% higher than in wild-type mitochondria.
Cell Nucleus↗
Postreceptorial refractoriness of prolactin release mechanisms.
While a first injection of the antidopaminergic benzamide drug, sulpiride, induced a large rise in plasma prolactin (PRL) levels in chronically cannulated adult male rats, a second injection given 2 h later was totally inactive although the pituitary content of the hormone was still 76% of the initial value. When the second injection was given 8 h after the first it was slightly effective, but when administered 24 h later it was as effective as the first. The second of two consecutive injections of haloperidol given at 2-h intervals, or an injection of morphine given 2 h after sulpiride, were incapable of inducing a release of PRL. Two hours after an injection of sulpiride, a 30-min period of immobilization stress induced a significant rise in plasma PRL levels. A significant rise in plasma PRL levels was also observed when larger doses of sulpiride were given 2 h after a first injection of the drug. Apomorphine was at least as effective an inhibitor of PRL secretion when given 2 h after sulpiride than when injected after saline. In vitro studies of dopaminergic binding sites revealed the presence, in pituitary glands of sulpiride-treated rats, of receptors not modified by the drug. These data suggest that the only plausible explanation for the ineffectiveness of the second of two consecutive injections of sulpiride is the development of a state of refractoriness of the mechanisms that subserve the release of PRL induced by suppression of the inhibitory dopaminergic tonus.
Animals↗
[Somatocrinin (GRF) stimulates the liberation of biologically active somatotropin (GH) in adult man].
Intravenous injection of four doses (75, 150, 300, 600 micrograms) of synthetic somatocrinin (GRF 44) greatly increases serum growth hormone concentrations in ten adult normal men in contrast to placebo. Mean peak values were identical. Plasma GH released under GRF stimulation was able to stimulate proliferation of NB2 cells.
Adult↗
Cancer pain: evaluation of electromyographic and electrodermal feedback.
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Adult↗
Survey of vomitoxin contamination of 1980 Ontario white winter wheat crop: results of survey and feeding trials.
During the harvesting of the 1980 Ontario white winter wheat crop, producers noticed pink discoloration on kernels; this was attributed to Fusarium mold. Grain elevator and boatload samples were analyzed for mycotoxin contamination. Vomitoxin levels up to 8 ppm were detected in samples from southwestern Ontario. Other suspected mycotoxins were either nondetectable or present in trace amounts. Fusarium-contaminated wheat and clean wheat were added to swine and poultry diets for feeding trials. Feed refusal and decreased weight gains were observed in pigs fed diets containing 0.3 and 0.7 ppm vomitoxin, but there was no vomiting or other ill effects. Adult roosters and laying hens fed diets containing vomitoxin levels similar to those of the pig diets did not show any overt toxicological effects. Chemical analysis of suspected field cases of vomitoxin-contaminated feed did not reveal high vomitoxin levels.
Animal Feed↗
The application of tissue adhesives in small bowel anastomoses.
One layer everted end-to-end anastomosis was performed on the small bowel of mongrel dogs. Cultures of Serratia marcescens were injected into the lumen. Twenty-four hours later the animals were reexplored, and peritoneal cultures were observed. In animals where Fibrin Seal (consisting of fibrinogen, cold insoluble globulin, factor XIII, platelet growth factor, antiplasmin, thrombin, and calcium chloride) was applied to the suture line, negative cultures were found except for two experiments in which dehiscence or contamination from the Serratia injection site occurred.
Animals↗
Attempts to bypass the need for splenectomy in splenic injury.
Within the last decade spleen salvage has been a controversial issue. Only recently, with the advances and utilization of modern technology in surgery, spurred by a better understanding of this immunologically important organ, preservation has become a reality. Numerous approaches have been suggested. Reported is a simple method of applying a new agent, Fibrin Seal (FS), to control hemorrhage from splenic injury. In a controlled study using 14 mongrel dogs, it is compared to the hemostatic ability of cryoprecipitate with thrombin and Avitene. FS is an adhesive material with hemostatic qualities consisting of fibrinogen, factor XIII, antiplasmin, cold-insoluble globulin, and platelet growth factor. FS appears to have cohesive and adhesive properties that result in more efficient hemostasis than the controls. FS conforms to the spleen surface, allowing manipulation of the organ without dislodgement of the coagulum. Follow-up laparotomy showed minimal tissue reaction. On the basis of these data, consideration of FS as an important hemostatic agent warrants clinical investigation.
Animals↗
Hemostasis in experimental pulmonary injury.
Fibrin Seal (consisting of fibrinogen, cold insoluble globulin, factor XIII, antiplasmin, platelet growth factor, thrombin, and calcium chloride), cryoprecipitate, at Avitene were applied to areas of pulmonary wedge resections in dogs and cynomologus monkeys in an attempt to stop bleeding and air leakage. In the control groups, hemorrhage persisted. Comparing the three hemostatic agents used. Avitene was the least effective followed by cryoprecipitate. Fibrin Seal was most effective. In all cases, it eliminated both air leakage and bleeding.
Animals↗
Imaging of outer segment periodicities in unstained cryoultramicrotomy sections of the frog retina.
Frog retinas were examined following cryoultramicrotomy. The extent of glutaraldehyde cross-linking ranged from maximally 2% for 2 h to no cross-linking. When the tissue was cryoprotected, the effects of hypotonic, isotonic and hypertonic media on outer segment banding periodicities were studied. The specimen was cryosectioned at 193 K to 113 K with sections collected on a dry knife (213 K to 123 K). The sections were freeze-dried and only rehydrated with phosphotungstic acid section stain when transmission electron microscopy was used to establish the extent of gross retinal morphology for each fixation protocol employed. As the extreme of no cross-linking and no cryoprotection was approached and reached, conventional sections which displayed extensive retinal morphology were not obtained. Instead, fragments of retinal tissue resulted which showed periodicities of alternating light and dark bands. These periodicities are interpreted as photoreceptor outer segment discs with contrast formation depending upon an interplay between three factors: mass density differences between disc and interdisc space, section cutting angle, and section thickness.
Animals↗