PubMed Health⌕ Search

Biomedical subjects

A S Gordon

Publications and source records attributed to A S Gordon.

At least 109 records · Page 6Linked to original sources
PubMed1983

Hepatic production of erythropoietin in a phenylhydrazine-induced compensated hemolytic state in the rat.

The relative roles of the kidney and liver as a source of Ep in a fully compensated hemolytic state were investigated. A compensated hemolytic anemia was induced in rats by injections of PHZ over a 6-week period. Verification of a fully compensated hemolytic state was established by MCV, MCH, MCHC, BV, PV, CRCV, peripheral reticulocyte counts, and bone marrow counts. The kidneys and livers of the PHZ-injected rats were subjected to concurrent perfusion at weekly intervals over the treatment period and the perfusate assayed for Ep activity. The kidney was found to be the principal source of Ep during the earlier stages of the anemia and the liver became increasingly important as a source of Ep during the later stages as the anemia became progressively compensated. By the fifth and sixth weeks of treatment, when the anemia was fully compensated, the livers of the PHZ-treated rats were the principal source of Ep. During these last 2 weeks of treatment, the amount of Ep recovered from the renal effluents of PHZ-injected rats was no greater than that collected from the renal effluents of saline-injected rats. The data indicate that the liver is the primary, if not the only, source of the higher titers of Ep in the fully compensated hemolytic state induced in the rat by long-term PHZ treatment.

Anemia, Hemolytic↗
PubMed1982

The influence of pancreatic hormones and diabetogenic procedures on erythropoietin production.

The influence of the pancreas on renal and extrarenal erythropoietin (Ep) production and on the elaboration of the hepatic erythropoietic factor (HEF) was studied in these experiments. Insulin was found to elevate Ep levels in the anephric hypoxic rat when compared to controls, whereas glucagon treatment augmented the hepatic Ep response to hypoxia in the subtotally hepatectomized (hepx) animal while lowering it in the renal intact rat. Production of experimental diabetes either through chemical induction by alloxan or following pancreatectomy diminished the Ep response in all groups tested. Treatment with antiglucagon caused an elevation in the Ep response to hypoxia in the intact rat but lowered Ep levels in the hepx animal. In addition, glucagon and a synthetic hepatotrophic agent (L-histidyl L-lysine acetate) stimulated HEF production in the hepx rat, although none of the agents tested were capable of enhancing HEF levels in the intact rat.

Animals↗
PubMed1982

Erythrocyte survival studies in a rat myelogenous leukemia.

To determine the extent intrinsic erythrocyte defects and/or extrinsic factors were involved in anemia of rats bearing Shay chloroleukemia (SCL), survival of 3H-DFP labeled erythrocytes was studied in leukemic and nonleukemic hosts. Red blood cells labeled before induction of leukemia, were rapidly lost from the peripheral circulation of SCL rats in terminal stages of disease. However, labeled erythrocytes from terminal SCL animals displayed normal lifespans when transfused into nonleukemic controls. Thus the anemia of this leukemia probably resulted from extrinsic factors associated with the leukemic process. Hemorrhage appeared to be primarily responsible for the anemia of this disease.

Anemia↗
PubMed1982

Studies on carbon tetrachloride-ethanol interactions in mice.

Male C57BL/6J (C57) and DBA/2J (DBA) inbred mice were dosed with either corn oil or carbon tetrachloride (CCl4) in corn oil 24 h before a 3.25 g/kg i.p. dose of ethanol. The CCl4 doses were increased in approximate half-log intervals (5, 15, 50, 150 or 500 microliter/kg, intragastrically (i.g.)). Blood acetaldehyde concentrations were significantly increased 1, 2, 3 and 4 h after ethanol administration at CCl4 doses of 15 microliter/kg and higher, with DBA and C57 mice exhibiting similar dose-response effects up to the 150 microliter/kg dose. A CCL4 dose of 500 microliter/kg produced differences in blood acetaldehyde elevation between the two inbred strains (DBA - 5-fold, C57 - 3-fold). Associated with the elevation of blood acetaldehyde content was a decrease in the rat of elimination of ethanol from blood. Using male genetically heterogeneous stock (HS) mice it was shown that phenobarbital pretreatment potentiated the CCl4-induced decrease in in vivo acetaldehyde oxidation. An equimolar dose of CHCl3 (0.5 mmol/kg) was without effect in either control or phenobarbital-pretreated mice. Mice pretreated with 0.5 mmol/kg, i.g., 1,2-dichloroethane, 1, 1,2-trichloroethylene or bromobenzene did not exhibit significant interaction with ethanol. These data show that in vivo acetaldehyde oxidation is inhibited by very low doses of CCl4 (15 microliter/kg, i.g.) and that this inhibition is enhanced by the cytochrome P-450-inducing agent phenobarbital.

Acetaldehyde↗
PubMed1982

Extramedullary hematopoiesis simulating parasagittal meningioma.

We report a patient with polycythemia vera and myeloid metaplasia of nine years duration who developed raised intracranial pressure related to a mass obliterating the sagittal fissure. Although clinically and radiologically simulating a meningioma, biopsy revealed extramedullary hematopoiesis involving the falx cerebri. Although uncommon, this case illustrates that myeloproliferative disease can present with symptomatology and radiologic features similar to primary intracranial tumours.

Adult↗
PubMed1982

Specificity and localization of the acetylcholine receptor kinase.

Acetylcholine receptor-phosphorylation has been compared in sealed and lysed right-side-out membrane vesicles prepared form Torpedo californica electric organ. Phosphorylation was increased 5- to 12-fold in hypotonically lysed vesicles as compared with untreated vesicles. Control experiments confirm that this enhancement is a result of increased permeability of the membrane to ATP. These data suggest that the acetylcholine receptor kinase is located on the cytoplasmic side of the plasma membrane. Results with detergent lysis support this conclusion. Although the acetylcholine receptor constitutes less than 10% of the total protein in these membranes, the kinase was found to be highly specific for polypeptides corresponding in molecular weight to acetylcholine receptor subunits.

Adenosine Triphosphate↗
PubMed1982

Microcalorimetric Measurements of Glucose Metabolism by Marine Bacterium Vibrio alginolyticus.

Microcalorimetric measurements of heat production from glucose by Vibrio alginolyticus were made to assess the viability of calorimetry as a technique for studying the metabolism of marine bacteria at organic nutrient concentrations found in marine waters. The results show that the metabolism of glucose by this bacterium can be measured by calorimetry at submicromolar concentrations. A linear correlation between glucose concentration and total heat production was observed over a concentration range of 8 mM to 0.35 muM. It is suggested that these data indicate a constant efficiency of metabolism for this bacterium over the wide range of glucose concentrations studied.

Journal Article↗
PubMed1982

Increased erythropoiesis and 2'5'-A polymerase activity in the marrow and spleen of phenylhydrazine-injected rats.

The rate of CFUE production in adult rats varies considerably according to whether the animals are rendered anemic by short or long term treatment with phenylhydrazine. The bone marrow responds during 2 months of phenylhydrazine injections with a progressive increase in CFUE, the spleen shows a rapid and larger rise after 3 daily injections followed by a decline to near zero, control numbers, after prolonged administration of the drug, and the liver never develops erythropoietic activity. Endogenous colonies, that is, colonies that grow in plasma clots without added erythropoietin, are most numerous in bone marrow after phenylhydrazine treatment, are always few in the spleen and are never present in cultures of liver cells. In both marrow and spleen, there is a direct correlation between the rate of erythropoiesis and 2'5'-A polymerase activity. These findings suggest that production of the enzyme may be an early event in erythroid cell differentiation.

2',5'-Oligoadenylate Synthetase↗
PubMed1982

Granulopoiesis and colony stimulating factor production in regenerating liver.

Partial hepatectomy (hepx) of the adult animal induces a substantial hepatic erythropoietin (Ep) response following hypoxia and results in a transient reinitiation of hepatic erythropoiesis. This phenomenon is associated with an elevation in the number and activity of the hepatic macrophages or Kupffer cells. Kupffer cells have been implicated in the production not only of Ep, but of the moiety which regulates granulocyte growth in vitro, Colony Stimulating Factor (CSF). Histological examination of the regenerating liver revealed some foci of granulopoiesis, but not to the extent noted for erythropoiesis. Granulopoiesis was not associated with islet conformations involving central reticular or macrophagic cells. In addition, serum derived from the hepatic venous drainage of hepx animals possessed moderate levels of CSF, as determined by its ability to promote the growth of granulocytic-macrophagic colonies in agar culture.

Animals↗
PubMed1982

Effects of anemia and hypertransfusion on neonatal marrow and splenic erythrocytic colony-forming units in vitro.

Employing the plasma clot culture system, the effects of anemia or plethora on 10-day-old neonatal rat bone marrow and splenic erythrocytic colony-forming units (CFU-E) were examined. Anemia induced by phenylhydrazine resulted in a decreased CFU-E population in the bone marrow and dramatically increased CFU-E numbers in the spleen. Transfusion-induced plethora increased CFU-E numbers in both the marrow and the spleen. These in vitro findings lend support to studies performed in vivo and further suggest that regulation of erythropoiesis in the neonatal rat differs from that observed in the adult.

Anemia↗
PubMed1981

The effect of prostaglandins A2,E1,E2,15 methyl E2, 16, 16 dimethyl E2 and F2 alpha on erythropoiesis.

Prostaglandins A2, E1, E2, methylated E2s, and F2 alpha affected erythropoiesis and/or erythropoietin (Ep) production. This action is indicated in the exhypoxic, polycythemic mouse where radioiron incorporations into RBC increased after administration of these compounds. The kidney and liver have been indicated through previous studies, to actively participate in Ep production. The kidney and liver have been indicated through previous studies, to actively participate in Ep production. By the removal of one of these active sites in a murine system treated with prostaglandins it is shown that a response is reflected in Ep levels. Interference of the action of prostaglandins (PG) is altered by the removal of these target sites of Ep production. The erythropoietic responses elicited by PGA2, E1, and perhaps the methylated PGE2s act through the liver whereas PGE2 may operate through a renal pathway for its response. PGF2 alpha reveals no effect on erythropoietic activity and is no different than that observed for vehicle-treated controls. The prostaglandins tested appear to act primarily through the kidney or liver but the possibility exists that some yet undetermined organ site may also be involved.

16,16-Dimethylprostaglandin E2↗
PubMed1981

The role of the father in his son's marijuana use.

In order to explore perceived paternal correlates of adolescent marijuana use (both alone and in interaction with perceived maternal correlates), 71 adolescent boys were interviewed with a questionnaire assessing their perception of paternal and maternal warmth, child-centeredness, control through guilt, autonomy, and identification. The results showed users are less likely to perceive their fathers as affectionate and child-centered. The absence of both paternal tolerance in control and maternal affection is also associated with adolescent marijuana use. The results are discussed in terms of the possible impact of the father in the context of the family on the adolescent's marijuana use.

Adolescent↗
PubMed1981

Maternal and personality determinants of adolescent smoking behavior.

This study examined the interconnection of maternal determinants and personality attributes of adolescent male tobacco users. The 39 mothers and their 39 sons were interviewed separately about their attitudes and the mother's child-rearing practices. The sons also responded to questions concerning their personality characteristics. In general, the findings indicated that adolescent tobacco use depends on the coexistence of certain personality predispositions and maternal conditions. Thus, with regard to personality factors, male smokers tended to be less in control of their impulses, less responsible and autonomous, more rebellious, and more likely to engage in interpersonal aggression. With respect to the coexisting maternal conditions, the mothers of smokers tended to be less traditional and affectionate, and less likely to serve as models for their sons.

Adolescent↗