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Biomedical subjects

G Wells

Publications and source records attributed to G Wells.

At least 199 records · Page 11Linked to original sources
PubMed1986

A comparison of confidence interval methods for the intraclass correlation coefficient.

Different methods of obtaining confidence intervals for the intraclass correlation coefficient rho in the unbalanced one-way random-effects model are investigated, focusing on applications to family studies. Methods based on simple modifications of formulas for the case of equal group sizes are found to provide adequate coverage at small to moderate values of rho. A method based on the large-sample standard error of the sample intraclass correlation, as derived by Smith (1956, Annals of Human Genetics 21, 363-373), is shown to provide consistently good coverage at all values of rho. A method proposed by Thomas and Hultquist (1978, Annals of Statistics 6, 582-587) also provides consistently good coverage, but generates mean interval widths substantially greater than those generated by Smith's method at values of rho likely to arise in practice.

Biometry↗
PubMed1985

Peripheral lymph flow in sheep with bacterial peritonitis: evidence for increased peripheral microvascular permeability accompanying systemic sepsis.

We studied the effects of systemic sepsis on peripheral microcirculatory fluid exchange by examining changes in flow (Qlymph) and lymph-to-plasma [L/P] total protein and albumin ratios from lymph draining, the efferent duct of a prefemoral lymph node in sheep, before and during surgically-induced peritonitis. After baseline study, peritonitis was produced by cecal ligation, perforation, and devascularization. By 24 hours blood cultures revealed a polymicrobial bacteremia. The hemodynamic response to the septic insult during the 72-hour study period was characterized by an increase in heart rate and an initial fall in stroke volume index; yet, the mean blood pressure remained unchanged from baseline levels throughout the study protocol. The intrapulmonary shunt fraction increased (p less than 0.05) by 48 hours, as did both the Qlymph (2.6 +/- 1.9 ml/hr to 6.8 +/- 4.6 ml/hr; p less than 0.05) and the calculated lymph albumin clearance (1.6 +/- 1.2 ml/hr to 3.1 +/- 1.7 ml/hr; p less than 0.05). Although the calculated serum to interstitial colloid osmotic pressure gradient fell (F = 4.37; p less than 0.04), both the [L/P] total protein and albumin ratios were unchanged from baseline throughout 72 hours of study. Further, [L/P] total protein ratios were unrelated to Qlymph (r = -0.20); as Qlymph (experimental/baseline) increased with sepsis, [L/P] total protein ratio (experimental/baseline) did not fall (r = +0.62). We therefore conclude that systemic sepsis, as represented by this model of bacterial peritonitis, results in increased peripheral microcirculatory fluid flux that is primarily a consequence of an increase in permeability of the peripheral microvascular exchanging membrane.

Animals↗
PubMed1985

Role of piperacillin in surgical prophylaxis of genitourinary infections.

One hundred sixty-five men and women undergoing open or transurethral urologic surgery participated in a study designed to compare the prophylactic efficacy and safety of piperacillin with those of cefotaxime when administered perioperatively. The piperacillin-treated group received 2 Gm one hour before surgery and 2 Gm three hours later, and the cefotaxime-treated group was administered 1 Gm on the same schedule. In 9 per cent of the piperacillin-treated patients and in 11 per cent of the cefotaxime-treated patients postoperative urinary tract infections developed, although no patient in either group had sepsis. The most frequently isolated pathogens were Escherichia coli and Enterococcus sp. As expected, the females in both surgical groups had a greater incidence of postoperative infections than did the males. No significant drug-related clinical reactions or changes in the results of the laboratory tests were encountered in either treatment group. Thus, a two-dose perioperative prophylactic regimen of piperacillin was as safe and as effective as a two-dose regimen of cefotaxime in preventing postoperative urinary tract infections or sepsis in these patients.

Bacterial Infections↗
PubMed1983

Vocational adaptation of patients on home dialysis: its relationship to personality, activities and support received.

This analysis identifies, in terms of relative contribution, seven independent variables which appear to be associated with the vocational adaptation of home dialysis patients. The tentative model created by the analysis can be used as a guide for assessing a patient's potential vocational adaptation. It has also identified some conditions associated with adaptation which are amenable to treatment by dialysis staff. Validation of the model, however, requires further testing with other patient groups.

Activities of Daily Living↗
PubMed1981

Utilization of prenatal genetic diagnosis in women 35 years of age and older in the United States, 1977 to 1978.

As a measure of access to and acceptability of prenatal chromosomal diagnosis among older gravidas, we determined the ratio of use of prenatal diagnosis among women 35 years of age and older in Alabama, California, Manhattan, and Nebraska for the period 1977-1978. Utilization ratios were higher in 1978. Overall, utilization ratios were between 6% and 28%, well below the adjusted rates of 40% to 50% found in certain United States and British localities. Urban women tended to have higher utilization ratios than had rural women, and white women had higher ratios than had black women. Ratios were extremely low for black and rural residents. The oldest women (those greater than or equal to 40 years), who were at fivefold greater risk than women 35 to 36 years of age, had less than a onefold increase in utilization over the latter groups. The vast majority of older gravidas initiated prenatal care sufficiently early in their pregnancies to receive prenatal diagnosis. Current program strategies need to ensure access to prenatal diagnosis, especially for women greater than or equal to 40 years of age, women who are black, and women who live in rural areas.

Adult↗
PubMed1981

The metabolism of 1,3-dibromopropane by the rat.

1. The metabolism of 1,3-dibromopropane had been investigated in the rat. Two conjugated metabolites have been isolated from the urine and identified as S-(3-hydroxypropyl)cysteine and N-acetyl-S-(3-hydroxypropyl)cysteine. 2. An oxidation product, identified as beta-bromolactic acid, has been isolated as a urinary metabolite. 3. 1,3-dibromopropane is not excreted unchanged in expired air or in the urine. Approx. 15% of the dose (100 mg/kg) is excreted as metabolic products over 50 h and 3.5% as CO2 within 6 h, indicating that oxidation is the main route of detoxication.

Amino Acids↗
PubMed1981

The comparative metabolism of 2-bromoethanol and ethylene oxide in the rat.

1. The metabolism of 2-bromo[U-14C]ethanol an [U-14C]ethylene oxide has been studied in the rat. 2. As both compounds give rise to similar amounts of two urinary metabolites, identified as S-(2-hydroxyethyl)cysteine and N-acetyl-S-(2-hydroxyethyl)cysteine, it is proposed that 2-bromoethanol is converted into ethylene oxide in vivo. 3. A minor metabolite of 2-bromoethanol has been identified as N-acetyl-S-(carboxymethyl)cysteine. 4. The metabolism of bromoacetaldehyde and bromoacetic acid has been investigated; N-acetyl-S-(carboxymethyl)cysteine had been shown to be a common urinary metabolite. 5. An oxidative metabolic pathway is proposed for 2-bromoethanol, via bromoacetaldehyde and bromoacetic acid, to N-acetyl-S-(carboxymethyl)cysteine.

Amino Acids↗
PubMed1979

Sub-mitochondrial and sub-microsomal distribution of creatine kinase in guinea pig myocardium.

Mitochondrial and microsomal fractions were isolated from guinea pig myocardium by differential pelleting. The mitochondrial fraction was subjected to analytical subfractionation by sucrose density gradient centrifugation and the gradient fractions assayed for marker enzymes for the various mitochondrial compartments, viz outer membrane (monoamine oxidase), intermembranous space (adenylate kinase), inner membrane (Mg2+-dependent ATPase and cytochrome c oxidase) and mitochondrial matrix (malate dehydrogenase), and for creatine kinase. Both creatine kinase and adenylate kinase were released by suspending the mitochondria in 50 mmol . litre-1 sodium phosphate buffer. Sonication or disruption with the detergent, digitonin released the adenylate kinase but the creatine kinase remained associated with the inner membranes. Subsequent salt treatment desorbed the creatine kinase from these membranes. It is concluded that creatine kinase is located to the outer aspect of the inner mitochondrial membrane. Analytical subfractionation of the microsomal fraction clearly resolved markers for the sarcolemma (5'-nucleotidase), outer mitochondrial membrane (monoamine oxidase) and endoplasmic reticulum (neutral alpha-glucosidase and RNA). Creatine kinase was localised in the endoplasmic reticulum particularly the smooth membranes.

Adenylate Kinase↗