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M A Shaw

Publications and source records attributed to M A Shaw.

At least 91 records · Page 5Linked to original sources
PubMed1984

The rare Lutheran blood group phenotype Lu(a-b-): a genetic study.

The rare blood group phenotype lacking Lutheran antigens, Lu(a-b-), is known to have two genetic backgrounds. Tests on 250000 blood donors show the frequency of Lu(a-b-) to be approximately 1 in 3000. The families of 41 propositi show the dominant inhibitor of Lutheran antigens, In(Lu), to be the usual cause of the phenotype in South East England; there was no proven case of the recessive background, LuLu. Lod scores for In(Lu) and other blood group loci are presented; the only hint of linkage is between In(Lu) and Rh. The suppressing effect of In(Lu) on the expression of antigens of unrelated blood group systems, P1, Aua and i, is confirmed.

Antigens↗
PubMed1983

Adsorption of pregnanediol-3 alpha-glucuronide by plastics and glass.

Radioactive pregnanediol-3 alpha-glucuronide at low concentration was found to bind to a number of common laboratory materials. Adsorption was greatest with polypropylene and unsilanised glass tubes. The presence of 0.1% gelatine reduced adsorption, except in polyethylene insert vials. Adsorption of pregnanediol-3 alpha-glucuronide may present a problem in radioimmunoassay studies.

Adsorption↗
PubMed1983

Urinary concentrations of steroid glucuronides in women taking oral contraceptives.

The aim of this study was to use measurements of urinary steroid glucuronides to confirm the suppression of ovulation of ovulation in women taking oral contraceptives. Urinary concentrations of oestrone-3-glucuronide (E1G) and pregnanediol-3 alpha-glucuronide (Pd-3-G) were measured by radioimmunoassay in early morning urine samples from six normally-menstruating women and six women who were taking combined oral contraceptives. In the normally-menstruating women, E1G concentrations, and the E1G/Pd-3-G ratio, increased 2-3 fold before ovulation. There was no midcycle increase in either measure in women taking oral contraceptives. We suggest that measurement of these steroid metabolites provides a means of assessing the anti-ovulatory effects of oral contraceptives.

Adult↗
PubMed1983

The effects of ovarian hormones on regulation of energy balance in Zucker rats.

Congenitally obese Zucker rats showed greater food intake, less running in activity wheels and greater body weight and fat content than the normal phenotype. Their food intake, running and body weight did not change significantly with the phase of the oestrous cycle. Ovariectomy had no effect on these variables or on body composition. Oestradiol replacement had little effect. Zucker rats of normal weight, however, showed a normal pattern of responses to the oestrous cycle, ovariectomy and oestradiol administration. The central regulation of energy balance and body weight appear to be insensitive to oestrogens in the obese Zucker rat.

Animals↗
PubMed1983

Plasma oestradiol-17 beta and testosterone concentrations as possible causes of the infertility of congenitally obese Zucker rats.

The plasma oestradiol-17 beta concentrations of obese and non-obese female Zucker rats have been measured in three phases of the oestrous cycle. The oestradiol concentrations of both phenotypes were similar, and changed normally with the oestrous cycle. The weights of the uteri also changed normally with the cycle. Plasma androgen concentrations in male Zucker rats have also been measured: the mean concentration was slightly but significantly lower in obese rats, and androgen-sensitive tissues were slightly reduced in weight. The oestradiol-17 beta concentrations in males of both phenotypes were similar. It seems unlikely that deficient plasma concentrations of gonadal hormones cause the infertility of obese rats of either sex.

Animals↗
PubMed1982

Human mitochondrial glycerol phosphate dehydrogenase (GPDm) isozymes.

1. A hydrophobic/phospholipid electrophoretic system has been devised which makes possible the analysis of human mitochondrial glycerol phosphate dehydrogenase (E.C. 1.1.99.5. GPDM). 2. GPDM has a wide tissue distribution in both adult and foetal life and is active in cultured lymphoblastoid cells and fibroblasts but is absent from red cells. 3. The solubilization procedure does not significantly alter the kinetic properties of the enzyme (Km alpha-glycerophosphate = 0.04-0.07 M, Km PMS = 0.19-0.35 mM) but the soluble form is less thermostable. 4. Comparisons of physicochemical characteristics, tissue distribution and coenzyme requirement point to a separate genetic determination and low level of evolutionary relatedness between GPDM and its cytosolic counterpart GPDS.

Animals↗
PubMed1981

Human succinate dehydrogenase: biochemical and genetic characterization.

A simple procedure for the preparation of soluble human succinate dehydrogenase is described. These preparations have proved suitable for analysis by zone electrophoresis, using a specific stain to detect activity after separation. In a survey of succinate dehydrogenase from various tissues and different individuals, no evidence for genetic heterogeneity due to the expression of either multiple loci or alternative alleles at the succinate dehydrogenase locus was found. However, epigenetic heterogeneity in both molecular size and charge was seen and various explanations for the occurrence of the isoenzymes are explored. Estimates of molecular size (93,300 +/- 9100) suggest that the smallest active unit of succinate dehydrogenase accounts for the major part of the solubilized activity. Kinetic studies have shown that the apparent Km values for succinate (0.9 mM) and PMS (0.4 mM) are comparable to those previously described for the beef heart enzyme, and these parameters were not significantly altered when the enzyme was removed from the membrane milieu. However a marked non-succinate-dependent activation of the membrane-associated enzyme at 38 C is apparently lost on solubilization, and this observation may have some bearing on earlier reports of an apparent decrease in Vmax on solubilization of succinate dehydrogenase.

Adult↗
PubMedDate not supplied

Urinary growth hormone excretion rates in normal and acromegalic man: a critical appraisal of its potential clinical utility.

The assessment of growth hormone (GH) secretory status is often difficult because of the intermittent nature of GH release and resulting wide swings in plasma GH levels. Urinary GH excretion holds promise as an index of integrated plasma GH free of this limitation, but technical problems have prevented its use until recently. We adapted a recently developed method for accurately measuring GH and its various molecular forms in urine to the determination of GH excretion rates. The method involves diafiltration and immunoextraction of GH from urine, with monitoring of recovery and final quantification by radioimmunoassay. Twenty-four h GH excretion rates were determined in 30 normal adults (15 men and 15 women) and 4 acromegalic patients. They ranged from 1 to 81 ng/24 h in men, from 1 to 70 ng/24 h in women and from 87 to 1660 ng/24 h in acromegaly (medians = 8.7, 18.0 and 267 ng/24 h, respectively). Excretion rates varied widely, not only between subjects, but also within the same subject on different days. Women and younger subjects tended to excrete more GH than men and older subjects, although these trends were not statistically significant. Acromegalics excreted significantly more GH than normals (p less than 0.001). Twelve normal subjects underwent simultaneous assessment of 24 h integrated plasma GH (sampling every 20 min) and urine GH excretion. Urine GH correlated weakly (r = 0.45) with integrated plasma GH.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗