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Biomedical subjects

R George

Publications and source records attributed to R George.

At least 217 records · Page 12Linked to original sources

Adenosine-5'-d: rotational conformation of the 5'-carbinol group.

A synthesis of adenosine-5'-d (4), and its p.m.r. spectral characteristics, are described. The presence of deuterium in 4 gives rise to a 2:1 mixture of R and S configurations at C-5, thereby permitting specific assignments for the resonances of the residual 5'-protons. From the observed spin-spin coupling between the latter and H-4', an estimate has been made of the rotamer population of the exocyclic 5'-carbinol group. It is shown that the gauche-gauche rotamer is preponderant (approximately 70%) and the gauche-trans one of minor importance (approximately 20%) in aqueous solution, which contrasts markedly with the preference for the latter rotamer exhibited by adenosine in the solid state.

Adenosine↗

Interaction of haemoglobin E with alpha-thalassaemia and haemoglobin Constant Spring.

The combination of Hb E,alpha-thalassaemia and Hb CoSp was found in a 20-year-old female Malay who presented with a moderately severe haemolytic anaemia. The findings in the patient and her family from which this diagnosis was arrived at are discussed. Although this is the first report of this condition in this country it is pointed out that one may see more such cases in the future if one is aware of this condition since Hb E, alpha-thalassaemia and Hb CoSp all occur at significant frequencies in this country.

Adult↗

Stimulation of hepatic biogenesis of sterols on administration of adenosine compounds.

1. Re-feeding starved rats increased the biogenesis of sterols in livers, with highest activity at 6h after the start of food intake. 2. Complete deficiency of protein or fat and partial deficiency of carbohydrate in the diet had no effect on sterol biogenesis. 3. Glucose, citrate or pyruvate, when administered intraperitoneally to starved rats, stimulated the biogenesis of sterols only at high concentrations. 4. ATP given intraperitoneally at low concentrations (10mg/rat) stimulated biogenesis of sterols, but not of fatty acids, from [1-14C]acetate. This effect was also obtained with other adenosine compounds, but not with adenine or guanosine. 5. Administration of adenosine compounds to starved rats also increased the incorporation of [1-14C]acetate into sterols in liver slices and also the activity of microsomal 3-hydroxy-3-methylglutaryl-CoA reductase. The results suggest a regulatory role for adenosine compounds in the hepatic biogenesis of isoprenoid compounds.

Acetates↗

An NIH/Columbia University information system interface.

The National Institutes of Health (NIH) and the Health Sciences of Columbia University have developed an information system interface whereby sponsored research information is routinely forwarded, in machine-readable form, from the NIH to Columbia University. For Columbia University the interface system has materially reduced data input costs, made information available on a more timely basis, improved the quality of its system by the adoption of existing standardized data definitions, and allowed flexible access to NIH's broad data base. For NIH the system permits an improvement in its data base through high-quality and fast feedback from the grantee institution. The promotion of future systems development is enhanced through the adoption of standardized data element designations and definitions.

Humans↗

Abnormal haemoglobins and hereditary ovalocytosis in the Ulu Jempul District of Kuala Pilah, West Malaysia.

A survey of abnormal haemoglobins and hereditary ovalocytosis was carried out among 629 Malays of Minangkabau descent in the Ulu Jempul District of Kuala Pilah, in the state of Negri Sembilan in West Malaysia.. Several abnormal haemoglobins were found with the following frequencies: Hb E 5.25%, Hb CoSp 2.38%, Hb A2 indonesia 0.80%, a fast moving Hb with a Mobility between A and Bart's 0.64% and Hb Q 0.16%. Hereditary ovalocytosis was found in 13.2% of these people. None of the persons with hereditary ovalocytosis had any evidence of haemolysis.

Adolescent↗

Acute morphine effects on regional brain amines, growth hormone and corticosterone.

Morphine sulfate was injected in doses of 5, 10 and 20 mg/kg i.p. to male rats at 3:00 pm. At 4:00 pm, the rats were decapitated and norepinephrine, dopamine and serotonin levels were measured in seven brain regions (cortex, striatum septum, amygdala, hypothalamus, midbrain and pons). Growth hormone and corticosterone levels were assayed from plasma. Saline-injected animals served as controls. The only significant change in brain amine level was an increase in striatal dopamine which occurred after 5 mg/kg morphine. 20 mg/kg caused an increase in plasma corticosterone; lower doses were ineffective. The dose for maximum growth hormone release was 10 mg/kg, although all three doses were effective. It was not possible to relate changes in brain amine levels with these hormonal responses to acute morphine administration.

Amines↗

Chronic morphine effects on regional brain amines, growth hormone and corticosterone.

This study was designed to examine the relationship between regional levels of brain amines (norepinephrine, NE; dopamine, DA; serotonin, 5-HT) and plasma hormone levels (corticosterone, CS; growth hormone, GH) in rats following chronic morphine administration (40 mg/kg twice daily). Rats were sacrificed at 4:00 pm (and the final injection was made at 9:00 am). Amine and hormone levels were determined after 1, 2 and 6 weeks of daily injections of morphine. Increased plasma CS was found after 1 and 2 weeks of injections and decreased GH levels were present after 2 and 6 weeks. In another 2 week study when morphine was administered 1 hr before sacrifice, plasma levels of CS were decreased and GH increased. Serotonin levels were decreased in all brain regions after 2 and 6 weeks of morphine administration and DA was decreased in the amygdala after 6 weeks. In 2 weeks treated rats injected 1 hr before sacrifice 5-HT levels had returned to control levels and DA was decreased. Inverse correlations were found to relate with 5-HT and CS levels, CS with GH levels and GH with brain DA. A direct correlation was present in GH and 5-HT levels.

Amines↗

Diurnal variations in plasma corticosterone and growth hormone as corrlelated with regional variations in norepinephrine, dopamine and serotonin content of rat brain.

Statistically significant diurnal variations in plasma growth hormone (GH) were found to occur in handled male rats. Peak GH values (at miday) appeared to be inversely correlated with the diurnal peak of plasma corticosterone(CS) which occurred after the onset of darkness. Brain amines were examined in the following regions: cortex, striatum, septum, amygdala, pons, midbrain, and hypothalamus. Statistically significant diurnal cycles of serotonin (5-HT) concentration were found in the amygdala and midbrain, significant diurnal alterations in norepinephrine (NE) levels. Ultradian dopamine (DA) cycles were significant in all regions examined. Plasma GH changes were found to be directly correlated with midbrain and amygdala 5-HT levels and with DA levels of all areas except the amygdala, Plasma CS was found to be inversely correlated with striatal and cortical DA and with 5-HT levels of amygdala.

Amygdala↗

Plasma corticoids in the respiratory distress syndrome and in normal infants.

Serial plasma samples for corticoid determination were obtained during the neonatal period in 16 infants with RDS (eight of whom died) and 44 healthy babies. The median corticoid level in the eight infants with RDS who was considerably higher than that of patients with RDS who survived, or the normal babies. The median corticoid level in the surviving RDS infants was statistically greater than that of the normal controls, but the actual difference was only 1.9 mug/100 ml. Simultaneous pH, PCO2, PO2, HCO3- and corticoid measurements were obtained serially in five patients with fatal RDS. However, the correlation between plasma corticoids and the acid-base determination was poor in all but one infant. It is concluded that infants are able to respond to severe physical stress in the neonatal period with an appropriate rise in plasma corticoid concentration, but lesser degrees of illness may cause only minimal changes in corticoid levels.

Adrenal Cortex Hormones↗