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L Fox

Publications and source records attributed to L Fox.

At least 109 records · Page 6Linked to original sources
PubMed1971

The ecology of micro-organisms in a closed environment.

Experimental data are presented which have a bearing on the susceptibility of astronauts to infectious diseases. These experiments include the observation of growth by two bacteria in Biosatellite 2, in which higher mean densities were attained than in earth-based controls. In addition, weightlessness combined with the special environment of a space vessel may affect the physiology of the astronauts. Earth-based studies in closed chambers were carried out under a variety of conditions with regard to pressure and oxygen content. One notable result was the transfer of micro-organisms from subject to subject. Comparative experiments were carried out in Antarctica and it was shown that the tests in closed chambers differed markedly from the Antarctica experience. The objectives and procedures of microbiological tests of the Gemini and Apollo programs are outlined.

Aerospace Medicine↗
PubMedDate not supplied

Potential role for P-glycoprotein in the non-proportional pharmacokinetics of UK-343,664 in man.

1. UK-343,664 is a potent and specific PDE5 inhibitor. Following single oral doses to human volunteers, it exhibited non-proportional pharmacokinetics over the dose range 30-800 mg. Over this 27-fold dose range, Cmax and AUCt increased 247- and 287-fold respectively. The half-life (4-6 h) was similar at all doses. No systemic exposure was quantifiable at doses <10 mg. 2. UK-343,664 is a lipophilic molecule (log D7.4 = 3.1) and as such is expected to be cleared mainly by metabolism. Based on studies with expressed human P450 enzymes it was concluded that the metabolism of UK-343,664 was predominantly mediated by CYP3A4. With a moderate Km = 76 microM for this enzyme, saturation of first-pass metabolism alone was considered unlikely to account for the non-proportional pharmacokinetics. 3. UK-343,664 showed high affinity for P-glycoprotein in vitro, with a Km = 7.3 microM. In transport studies in LLC-PK1 cell monolayers transfected with P-glycoprotein, UK343,664 showed marked polarized transport which was concentration dependent. 4. The high affinity of UK-343,664 for P-glycoprotein is considered to be the primary source of the non-proportional pharmacokinetic profile observed in man.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMedDate not supplied

Protein catabolic rate in patients on continuous peritoneal dialysis. A multivariate predictive model.

Protein catabolic rate (PCR) and PCR normalized to standard weight (PCRN) are important indices of nutrition in patients on continuous peritoneal dialysis. The purpose of this study was to test whether urea clearance is among the predictors of PCR and PCRN in a multivariate analysis. Stepwise logistic regression was used to develop separate models for low PCR and low PCRN on a set of 143 urea kinetic studies in 92 patients on continuous peritoneal dialysis. The regression models were tested on an independent sample of 189 urea kinetic studies in 102 patients on continuous peritoneal dialysis by deriving the area under a receiver operating characteristic curve. In the derivation set, low serum urea, high serum creatinine, low urine and dialysate drain volumes, and low body surface area were identified as predictors of PCR < or = 50 g daily. The area under the receiver operating characteristic curve in the validation set was 0.930 (95% confidence interval: 0.915-0.945). Low serum urea, male gender, high body mass index and low urea fractional clearance (KT/V) were predictors of PCRN < or = 0.80 g/kg daily. The receiver operating characteristic area for this model was 0.948 (95% confidence interval: 0.926-0.970). Logistic regression analysis was repeated twice after adding urea nitrogen excretion normalized to standard weight (UNEN) as a candidate variable. This process identified low UNEN, male gender, and obesity as the predictors of low PCRN, and low UNEN, male gender, low urine volume, low drain volume normalized by body water, and high serum albumin as predictors of low KT/V urea. The authors conclude that PCR and PCRN can be predicted by models that incorporate serum azotemic indices, body size and composition, and direct or indirect measurements of urea clearance. Small body size and lean body composition predict low PCR but high PCRN values. Both PCRN and KT/V urea are predicted by UNEN. Multivariate analysis cannot, therefore, rule out the hypothesis that PCRN and KT/V are linked mathematically.

Body Weight↗
PubMedDate not supplied

Variation in the process of pediatric asthma care.

In May 1994, the continuous quality improvement team at Hermann Children's Hospital in Houston, TX, began to study the structure, process, and outcome of asthma care for pediatric patients. The team's immediate goals were to identify variation in the treatment of pediatric asthma and to determine the most cost-effective interventions. This article details the team's development of a clinical pathway to reduce variation in patient care; use of the pathway led to a reduction in length of stay and a corresponding reduction in costs.

Adolescent↗
PubMedDate not supplied

Adverse ocular effects of acetate hemodialysis.

In order to better define ocular dynamics during hemodialysis, we studied intraocular pressure (IOP) and anterior chamber depth (ACD) serially during both acetate and bicarbonate hemodialysis in 10 stable hemodialysis patients. IOP did not change significantly in any patient during dialysis. In contrast, however, ACD decreased significantly during acetate but not bicarbonate dialysis. ACD could be maintained during acetate dialysis by concomitant administration of mannitol. We conclude that acetate dialysis might adversely affect ocular dynamics in susceptible patients with glaucoma or recent ocular surgery. In such individuals administration of mannitol or use of a bicarbonate dialysate should be considered.

Acetates↗
PubMedDate not supplied

Under guarantee.

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Health Care Rationing↗
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Personal service.

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Humans↗