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Biomedical subjects

V Walker

Publications and source records attributed to V Walker.

At least 73 records · Page 4Linked to original sources
PubMed1987

Ectopic ACTH production by a thymic carcinoid tumour.

An ACTH-producing thymic carcinoid tumour was diagnosed in a 10-year-old girl, 8 years after bilateral adrenalectomy for Cushing's syndrome. The peptides produced by the tumour were characterised thoroughly. High circulating levels of beta-endorphin and other peptides may have contributed to mood and behaviour disturbances.

ACTH Syndrome, Ectopic↗
PubMed1987

Oral nimodipine reduces prostaglandin and thromboxane production by arteries chronically exposed to a periarterial haematoma and the antifibrinolytic agent tranexamic acid.

The calcium antagonist nimodipine blocks the effects of many vasoconstrictors of cerebrovascular smooth muscle and may reduce the incidence of delayed cerebral ischaemia following subarachnoid haemorrhage though not necessarily by inhibiting the development of angiographic cerebral vasospasm. Post-haemorrhagic CSF contains abnormally large quantities of various eicosanoids that partly reflect enhanced production by cerebral arteries. Does nimodipine affect this process? The extra-arterial and intra-arterial production of PG6 keto-F1 alpha, PGE2, PGF2 alpha and TXB2 were measured in perfused common carotid arteries taken from rabbits in which the arteries had been ensheathed by blood clot in vivo for 7 days. All rabbits were given the antifibrinolytic agent tranexamic acid to retard resolution of the clot, and half were given oral nimodipine (2 mg/kg/day) for 10 days. Nimodipine significantly reduced the extra-arterial production of TXB2 during the third and fourth hours of perfusion and, less consistently, the production of PGF2 alpha, PGE2 and PG6 keto-F1 alpha. Lutrol, the solvent for nimodipine, had no such effect.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Zinc and genital infections.

The zinc status of 19 patients with chronic or recurrent genital infections and 18 patients with non-recurrent genital infections was assessed by measuring plasma and leucocyte zinc concentrations. Neither group of patients had plasma or leucocyte zinc concentrations that differed significantly from those of matched healthy controls. Each of six patients with chronic candidiasis had anergy to candidal antigen, as shown by delayed cutaneous hypersensitivity to intradermal injection of the antigen, but their zinc status was normal. This study provided no evidence of zinc deficiency in this small number of patients with acute non-recurrent or chronic recurrent genital infections.

Adult↗
PubMed1987

Ready, set, go. Wellness movement focuses business efforts on improved worker fitness, health.

From its conception in the mid-1970s to the present, attention to fitness and education regarding preventive measures has increased at a phenomenal rate. Companies are involved in the attempt to keep employees healthy and health care cost-efficient. Reduced absenteeism, less turnover, more positive work attitudes, less strain and tension, improved work performance and health-related savings are but a few of the benefits cited by those involved in maintaining healthy lifestyles. At a time when the health care industry is undergoing major cost containment efforts, it seems most reasonable to adopt a preventive mindset and be concerned with employee fitness and lifestyle programs that lead to a decrease in immediate health care utilization.

Health Promotion↗
PubMed1986

Bronze baby syndrome, biliary hypoplasia, incomplete Beckwith-Wiedemann syndrome and partial trisomy 11.

A premature infant with duplication of material from chromosome 11 and some features of the Beckwith-Wiedemann syndrome developed the bronze baby syndrome when exposed to phototherapy. He subsequently developed hepatocellular dysfunction and died aged 5 weeks. Post mortem examination revealed striking hypoplasia of intralobular bile ducts but little inflammatory change or necrosis in the liver.

Beckwith-Wiedemann Syndrome↗
PubMed1986

Reaction of DNA with chemically or enzymatically activated mitomycin C: isolation and structure of the major covalent adduct.

The antitumor antibiotic mitomycin C is shown to form a covalent complex with calf thymus DNA under anaerobic conditions in the presence of either NADPH cytochrome c reductase/NADPH, xanthine oxidase/NADH, or the chemical reducing system H2/PtO2. Digestion of the complex with DNase I/snake venom diesterase/alkaline phosphatase yields a single mitomycin deoxyguanosine adduct as the major DNA alkylation product, identified as N2-(2'' beta,7''-diaminomitosen-1'' alpha-yl) 2'-deoxyguanosine (Structure 2). Two minor adducts, 2-5% each of the total adduct pool, are isolated and identified as the 1'' beta stereoisomer of 2 (Structure 3), and 10''-decarbamoyl-2 (Structure 7). The same results were obtained with M13 DNA and poly(dG-dC).poly(dG-dC); however, in the latter case, a minor adduct apparently possessing two deoxyguanosine and one mitomycin unit is isolated. Digestion of the covalent mitomycin-calf thymus DNA complex with nuclease P1 yields four dinucleotide adducts, all of which consist of 2 linked at its 3' end to each of the four possible 5' nucleotides (A, T, G, and C). Upon treatment of each dinucleotide adduct with snake venom diesterase/alkaline phosphatase, 2 is released along with the corresponding free nucleoside. In apparent conflict with the present results, previous reports from another laboratory have indicated that modification of calf thymus DNA by mitomycin C under conditions identical to those described here result in the isolation of three mitomycin C mononucleotide adducts possessing linkages of the drug to N2 and O6 of guanine and N6 of adenine. Evidence is shown suggesting that the latter adducts are actually three of the above four dinucleotide derivatives of 2 obtained independently by us and, thus, all of them in fact possess an identical N2-mitosenylguanine adduct moiety. Model-building studies indicate an excellent fit of the guanine N2-linked drug molecule inside the minor groove of B-DNA with no appreciable distortion of the DNA structure.

Alkaline Phosphatase↗
PubMed1986

The sodium and potassium intake of 3 to 5 year olds.

The sodium intake of preschool children in their home environment was investigated and the major sources of sodium other than added table salt identified. Thirty five children from a Southampton general practice were studied. Twenty four hour urinary sodium excretion was measured as a reliable indicator of daily total sodium intake. The daily intake of sodium other than that from added table salt, and of potassium and other nutrients, was also calculated from three day dietary diaries collected using the household measures method. Median excretion of sodium was 62 mmol/24h (range 28-105, 28 urine collections) and of potassium was 25 mmol/24 h (range 14-46). The sodium:potassium ratio was 2.7 (1.4-5.2). From the diaries, the average daily intake of sodium was 68 mmol (32-98) and of potassium was 47 mmol (24-95), and the sodium:potassium ratio was 1.4 (0.5-2.7) (median and ranges, 35 children). Foods contributing more than 30 mmol sodium to one day's intake were mainly processed convenience foods.

Child, Preschool↗
PubMed1985

Fluid balance and secretion of antidiuretic hormone following transsphenoidal pituitary surgery. A preliminary series.

Hyponatremia developing some days after transsphenoidal pituitary adenectomy is a treacherous complication of uncertain cause. Of 19 patients monitored in a pilot study at the Wessex Neurological Centre, plasma sodium fell below 125 mmol/liter in three patients at times ranging from 6 to 9 days postoperatively. One patient had evidence of inappropriate secretion of arginine vasopressin (AVP), and the other two probably had steroid insufficiency despite apparently adequate steroid cover. In a more detailed study, the fluid and sodium balance of a further 16 patients was monitored for 7 to 11 days following transsphenoidal surgery together with plasma cortisol, renin, and AVP concentrations. No patient became severely hyponatremic. Three developed partial diabetes insipidus. Two patients with Cushing's disease had evidence of postoperative corticosteroid insufficiency despite normal steroid protection. An inappropriately low plasma cortisol concentration was recorded in both. Plasma AVP concentrations did not show a delayed surge postoperatively. Delayed hyponatremia appears to occur most often in patients with hypoadrenalism, as glucocorticoid cover is decreased. It results from water retention combined with natriuresis, and is reversed by glucocorticoid treatment.

Adenoma↗
PubMed1984

Production of prostaglandins and thromboxane by isolated cells from intracranial tumours.

Tumour cell-rich platelet-free preparations were isolated from 21 fresh samples of human intracranial tumours using enzymic digestion, followed by discontinuous density gradient centrifugation on Percoll and (14 preparations) adherence on plastic. Of the disaggregated cells 79.8 to 97.7% (mean 86.2%) were tumour cells, and mean cell viability was 82.6%. All the tumours produced prostaglandin (PG), E2, F2 alpha, 6 oxo F1 alpha and Thromboxane B2 during 16 hours of incubation but the amount varied widely. Highest production of PGE2 and TXB2 per 10(5) cells was by the eight meningiomas in which the prostanoid profile closely resembled that of circulating monocytes.

6-Ketoprostaglandin F1 alpha↗