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Biomedical subjects

G Evans

Publications and source records attributed to G Evans.

At least 289 records · Page 16Linked to original sources
PubMed1980

The interrelationship between hormones, psychotropic drugs and the opiate receptor--a pilot study.

Earlier reports had shown pronounced effects of clomipramine on plasma pituitary and gonadal hormone levels. In a continuation of these studies no change could be seen in rat plasma corticosterone levels following long-term, toxic administration of the drug despite a marked adrenal hyperplasia. It had been suggested that the action of clomipramine might be potentiated through the opiate receptor. Initial experiments using a rat model system have shown that morphine increased plasma prolactin and reduced plasma luteinizing hormone levels in vivo and that these effects could be overcome by naloxone. No direct effect of enkephalins was observed on rat pituitary organ cultures. The results are discussed in the light of recent findings of the relationship between properties of the opiate receptor and the observed side effects of tricyclic antidepressant therapy.

Animals↗
PubMed1980

Immunonephelometric assay of human apolipoprotein AI.

We report an immunonephelometric assay for apolipoprotein AI, which involves use of a laser nephelometer and an antiserum prepared in our laboratory. Coefficients of variation were 2.5% within-run, 6.3% between-run. Several types of manipulation of the samples (heating, delipidation, dissociation with urea), reportedly necessary for accurate determinations by radioimmunoassay or gel diffusion immunoassay, did not substantially affect results obtained with our technique. The assay is sensitive, reproducible, and simple, and appears suitable for routine use.

Apolipoprotein A-I↗
PubMed1979

Purification and properties of endo-beta-N-acetylglucosaminidase L from Streptomyces plicatus.

An enzyme, previously described as endo-beta-N-acetylglucosaminidase L (Tarentino, A.L., and Maley, F. (1974) J. Biol. Chem. 249, 811-817) because of its apparent specificity for Man(GlcNAc)2Asn, has been purified to homogeneity. The enzyme has now been found to hydrolyze (GlcNAc)3 to (GlcNAc)2 plus GlcNAc, and (GlcNAc)4 to 2(GlcNAc)2, at twice the rate observed for Man(GlcNAc)2Asn. Removal of the asparagine from the latter compound reduces the rate of hydrolysis by about 30-fold. Reduction of (GlcNAc)3 to GlcNAc beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc-ol eliminates this compound as a substrate for endo-beta-N-acetylglucosaminidase L. However, the reduction of (GlcNAc)4 does not affect its rate of hydrolysis. Endo-beta-N-acetylglucosaminidase L consists of a single polypeptide chain with a molecular weight of 49,500 +/- 400, which on isoelectric focusing separates into two closely migrating bands; a major with a pI of 4.25 and a minor one with a pI 4.20. Both bands possess similar enzyme activities and amino acid compositions, but differ slightly in their tryptic peptide maps.

Acetylglucosaminidase↗
PubMed1979

Short-term effects of CHO, fat and protein loads on total tryptophan/tyrosine levels in plasma as related to %REM sleep.

The effect on plasma amino acid levels and sleep parameters of three experimental diet conditions was investigated in 12 healthy young men. A total of 71 sleep records and 715 plasma samples were analysed for %REM (TDT) and total plasma tryptophan and tyrosine respectively. The ratio of tryptophan to tyrosine was virtually the same under the fat supplement as under the nosupplement conditions. The ratio associated with the CHO load was found to be 14 per cent higher, however. A 29 per cent higher value found with the Protein load may be misleading due to the nature of the supplement used. %REM (TDT) was not found to be significantly related to any of the above conditions.

Adolescent↗
PubMed1976

Recurrent hormone dependent chorea: effects of oestrogens and progestogens.

A case of hemi-chorea is described in a young woman, initially following administration of an oral contraceptive pill and recurring in a subsequent early pregnancy. The chorea ceased with the removal of the aetiological factor on each occasion. Subsequent challenge with a combined oestrogen/progestogen pill resulted in recurrence of the chorea, but the patient has been successfully maintained on a progestogen without any further symptoms. Thus it would appear that oestrogen component was the precipitating factor for the chorea.

Adolescent↗