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Biomedical subjects

M Wynn

Publications and source records attributed to M Wynn.

31 records · Page 2Linked to original sources
PubMed1988

Nutrition around conception and the prevention of low birthweight.

About 80 per cent of perinatal deaths are associated with low birthweight. Mothers' prepregnancy weight for height is correlated with birthweight, but this is only a crude indication of the close connection between low birthweight and maternal consumption of energy, protein and a range of other nutrients before and around the time of conception. Diet influences follicular growth before ovulation and thus affects ovulatory maturation and the number and quality of ova produced. Immediately after fertilisation diet affects the rate at which ova proceed to first and subsequent cleavages and therefore the size of the subsequent fetus. Diet acts not only directly on follicular and embryonic growth but indirectly by affecting gonadotropin secretion. The endocrine system is sensitive to blood concentrations of amino acids and some vitamins and minerals. Gonadotropin secretion is also depressed by smoking, and by some drugs, poisons and diseases, which may as a result also affect birthweight.

Animals↗
PubMed1988

Magnesium and other nutrient deficiencies as possible causes of hypertension and low birthweight.

7.2 per cent of babies born in England and Wales in 1986 had birthweights below 2,500 g. Low birthweight and hypertension are associated. European trials have reported that oral supplementation with physiological amounts of magnesium during pregnancy reduces pregnancy hypertension and also miscarriage, preterm birth and fetal growth retardation. Magnesium deficiency causes hypertension and low birthweight in animals. In humans deficiency of thiamin and other B vitamins has also been reported to cause pregnancy hypertension and low birthweight. Magnesium and B vitamins are essential for the same biochemical reactions in energy metabolism. There is evidence that magnesium consumption of substantial numbers of women in Europe and North America is too low to support a healthy pregnancy. Magnesium and thiamin are lost in processing many foods. British trials of magnesium supplementation are advocated. It is suggested that more attention should be given to magnesium in nutritional advice.

Female↗
PubMed1985

Management of pancreatic and duodenal trauma.

Eighty-four patients were treated for pancreatic or duodenal injuries or both over a 13 year period. Isolated contusion of the duodenum was managed by drainage only, and disruption was managed with primary closure, coverage of the closure with a serosal patch, and drainage. Patients with distal pancreatic injuries that involved the body or tail of the pancreas and were total or near-total transections underwent distal pancreatectomy and splenectomy. The difficult areas of management continue to be the type III and IV pancreatic and duodenal injuries. Extensive pancreatic resection should be reserved for those situations in which the pancreas has been devitalized and it is not expected that resolution will occur with drainage. The mortality in combined severe pancreatic and duodenal injuries was 64 percent with death related to associated injuries in most cases; however, extensive resection (Whipple procedure) in two cases led to death because of leakage from the anastomosis with subsequent retroperitoneal infection. Postoperative management of patients with pancreatic and duodenal injuries should always include careful attention to nutrition.

Abscess↗
PubMed1983

Reduction of laccase type 1 copper by 3,4-dihydroxyphenylalanine and other catechol derivatives.

3,4-Dihydroxyphenylalanine (DOPA) is not a preferred substrate of Rhus vernicifera laccase, as rate constants for the anaerobic reduction of the type 1 cupric atom by L-DOPA (6.3 X 10(1) M-1 s-1), D-DOPA (2.6 X 10(1) M-1 s-1), and L-DOPA methyl ester (2.6 X 10(1) M-1 s-1) are considerably smaller than k1 (catechol) (7 X 10(2) M-1 s-1) and rate constants characteristic of numerous other nonphysiological organic substrates (25 degrees C, pH 7.0, I = 0.5 M). The reactions of DOPA derivatives with laccase are unique, however, in that a two-term rate law pertains: kobsd = k0 + k1[phenol]; k0(L-DOPA) = 7 X 10(-2) s-1. The reactivities of other catechol derivatives (pyrogallol, gallic acid, and methyl gallate) with laccase type 1 copper were also examined.

Catechols↗
PubMed1982

Anation of laccase type 2 copper by azide and thiocyanate ions.

A mechanistic study of the anation of type 2 Cu(II) in fully oxidized laccase by azide and thiocyanate ions (X-) is reported. The rate data support a mechanism involving rapid formation of an outer-sphere complex (laccase . X-) followed by rate-limiting dissociative interchange to give the inner-sphere complex (laccase-X-) product: (formula; see text) Rate parameters for the laccase-azide reaction are k'2 = 1.25 X 10(-1) s-1 and k'-2 = 1.50 X 10(-2) s-1; those for the laccase-thiocyanate reaction are k'2 = 2.0 X 10(-2) s-1 and k'-2 = 1.1 X 10(-2) s-1 (25 degrees C, pH 6.1 phosphate buffer, I = 0.5 M). Although the rate law for anation of type 2 Cu(II) by N3- in 2-(N-morpholino)ethanesulfonic acid (Mes) or acetate medium (kobsd = k3 + k4[N3-]) differs from that observed in phosphate buffer, the data may still be accounted for in terms of the above mechanism, with Kos[N3-] much less than 1 [in Mes, k3 = 2.2 X 10(-2) s-1 and k4 = 3.3 X 10(-1) M-1 s-1; in acetate, k3 = 2.1 X 10(-2) s-1 and k4 = 3.4 X 10(-1) M-1 s-1 (25 degrees C, pH 6.0, I = 0.25 M)]. The equilibrium and spectroscopic characteristics of the laccase type 2 Cu(II)-N3- complex are compared with those of low molecular weight copper(II)-azide species, and the factors responsible for the very low substitutional reactivity of the type 2 cupric ion are discussed.

Anions↗
PubMed1979

Next year's pay.

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Allied Health Personnel↗
PubMed1973

The amino acid sequences of cytochromes c-551 from three species of Pseudomonas.

The amino acid sequences of the cytochromes c-551 from three species of Pseudomonas have been determined. Each resembles the protein from Pseudomonas strain P6009 (now known to be Pseudomonas aeruginosa, not Pseudomonas fluorescens) in containing 82 amino acids in a single peptide chain, with a haem group covalently attached to cysteine residues 12 and 15. In all four sequences 43 residues are identical. Although by bacteriological criteria the organisms are closely related, the differences between pairs of sequences range from 22% to 39%. These values should be compared with the differences in the sequence of mitochondrial cytochrome c between mammals and amphibians (about 18%) or between mammals and insects (about 33%). Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 50015 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 5.

Acetone↗