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Biomedical subjects

S Fenton

Publications and source records attributed to S Fenton.

65 records · Page 4Linked to original sources
PubMed1978

Preliminary studies with the sensitive cytochemical assay for parathyroid hormone.

A modification of the cytochemical assay for parathyroid hormone (PTH) is described which permits the measurement of as little as 0.1 fg ml-1. Using this assay circulating concentrations in normal humans range between 1 and 30 pg ml-1 using a bovine PTH standard. Elevated values are found in hyperparathyroidism with reduced concentrations in hypoparathyroidism. Where detectable, PTH concentrations measured by radioimmunoassay are on average fourteen-fold higher than by cytochemical assay. No cross reactivity was found with AVP, calcitonin and 1,25 dihydroxy vitamin D in concentrations normally found in health or disease.

Adult↗
PubMed1977

Partial body calcium measurements on patients with renal failure.

The bone calcium status of 39 patients with chronic renal failure on hemodialysis has been measured by in vivo neutron activation analysis (IVNAA) and reported in terms of a calcium bone index (CaBl) which relates the calcium in a patient to that in a normal person of the same height. In 20 of the 39 cases sequential measurements were made over periods of up to 40 mo. The results are compared with data obtained by radiology and by histological examination of bone biopsies. CaBl values varied from below normal to, in one case, above the range of normal. Many of the higher values were associated with demonstrable osteosclerosis. As found in previous work here with IVNAA, significantly low values of CaBl were associated with vertebral deformities; however, some patients with deformity had normal CaBl values, indicating that these had both local mineral loss (resulting in fracture) and osteosclerosis. Taken all together, the data suggest that more than half the patients have osteosclerosis. Sequential data showed no uniform response to treatment.

Adult↗
PubMed1976

Factor V in an industrial population.

Factor-V levels have been measured in a random sample of 626 men and 307 women working in a variety of occupations in North West London. The method is an automated one-stage assay using the same batch of freeze-dried thromboplastin, all results being expressed in terms of the same freeze-dried standard plasma; it has been shown that only one dilution of test plasma is necessary. Factor-V levels are significantly higher when venepuncture is difficult than when it is satisfactory, the mean levels being about 130% and 117% respectively. Factor-V levels are approximately normally distributed; they are similar in men and women and in blacks and whites, and increase significantly with age at the rate of about 0.6% per annum. Factor-V levels are not affected by oral contraceptives or the menopause, and there are no differences according to blood group or secretor status.

Adult↗
PubMed1974

Pseudomembranous colitis associated with antibiotic therapy - an emerging entity.

Two cases of pseudomembranous colitis are presented. The first patient had been treated with novobiocin-tetracycline and penicillin, and two weeks later developed severe fulminating diarrhea with ascites and bilateral pleural effusions which did not respond to intravenous ACTH. Subsequently she underwent subtotal colectomy and made a rapid and complete recovery. The second patient developed severe diarrhea two weeks after a 10-day course of clindamycin. She was treated with intravenous ACTH, oral Lactobacillus and a fecal enema and made a complete recovery.These cases reconfirm the importance of antibiotics as etiologic agents in this disease. They also stress the classic sigmoidoscopic and histologic findings that should facilitate prompt and rapid diagnosis.

Adolescent↗
PubMedDate not supplied

The hazards of using active clinic patients as a source of subjects for clinical studies.

The authors describe and empirically demonstrate a form of bias that results from deriving subjects for clinical studies from available patients currently being followed in specific disease clinics instead of inception cohorts (patients enrolled at a uniform and early point in their disease). They label this effect "clinic patient bias." It is a variation of prevalence-incidence (Neyman) bias in that it also results from the time gap between the onset of a specific characteristic (a risk factor, exposure or disease) and enrollment in the study, causing selective exclusion of fatal or short episodes, or mild or silent cases. Clinic patient bias may distort an estimate of relative risk in either direction. The empirical example is derived from a study of risk factors for developing complications such as peritonitis among end-stage renal disease patients treated with continuous ambulatory peritoneal dialysis (CAPD). The use of available clinic patients rather than an inception cohort (patients newly beginning CAPD) resulted in the demonstration of false apparent risk relationships for two variables: the calendar date when patients began CAPD (with those enrolled at an earlier time appearing to be at lower risk), and serum albumin level at the start of CAPD (with those having lower albumin levels appearing to be at higher risk). This example demonstrates one of the potential hazards of using active or available clinic patients as a source of subjects for clinical studies.

Cross-Sectional Studies↗
PubMedDate not supplied

Cadaveric renal transplant failure: the short-term sequelae.

Quality of life was evaluated in 103 patients initially when each was placed on the waiting list for a cadaveric transplant. Patients who were not transplanted were reassessed six months after being placed on the waiting list. Patients who received a transplant were reassessed six months after the surgery. Cadaveric transplantation was performed in sixty-three patients by the time of follow-up. The mortality rate of 12.7 percent in transplanted patients after six months was more than twice that in patients who remained on the waiting list without a transplant, but this difference was not statistically significant. There was a graft failure rate of 23.6 percent among transplanted patients who survived six months. Graft failures were associated with some deterioration in subsequent physical activity (F = 5.4, p less than 0.03) but not in psychosocial functioning. Successful cadaveric transplants were associated with a marked and significant improvement in psychosocial well-being (F = 10.5, p less than 0.002) after six months even though physical activity did not increase. These findings suggest that 1) a successful cadaveric transplant is associated with an improved quality of life, 2) the graft failure rate of 23 percent with cadaveric transplantation is still appreciable but 3) graft failure is not necessarily associated in the short term with deterioration in psychosocial well-being.

Adolescent↗