Biomedical subjects

D Warren

Publications and source records attributed to D Warren.

72 records · Page 4Linked to original sources

PubMed1980

Atenolol kinetics in renal failure.

Blood and urine levels of atenolol were measured in 12 subjects--2 anephric and 10 with creatinine clearances ranging from 0 to 122 ml/min/1.73 m2. In a single-dose study subjects were given atenolol 100 mg by mouth, and blood and urine levels were measured during the subsequent 72 hr. In a repeated-dose study 10 subjects were given atenolol 100 mg for 20 days, and blood and urine levels were measured before and for 72 hr after the final dose on day 21. In the single-dose study the peak blood level occurred later and the 24-hr plasma concentrations increased as creatinine clearance decreased. The range in peak blood level was sixfold throughout this range of creatinine clearance. The blood atenolol half-life (t1/2) increased from about 6 hr to more than 100 hr with progressive renal failure and there was a corresponding decrease in elimination rate constant and increase in area under the curve. In the repeated-dose study there was good correlation between predose blood level of atenolol and both logarithm creatinine clearance and serum creatinine, and the elimination rate constant correlated with creatinine clearance and the logarithm of serum creatinine. In the single-dose study minimum heart rates were observed just after the peak atenolol level. Blood pressure response did not correlate closely with serum atenolol levels. Dosing recommendations are suggested for patients with renal failure to take account of the effects of renal function on atenolol kinetics.

Adult↗

PubMed1980

Acute renal failure complicating Legionnaires' disease.

A 45-year-old man developed symptoms of pneumonia while on holiday in Spain. On his return home, a diagnosis of Legionnaires' disease was confirmed, complicated by acute renal failure, He was treated with dialysis and spontaneous recovery of renal function began on day 19.

Acute Kidney Injury↗

PubMed1978

Measurements of muscle stiffness and the mechanism of elastic storage of energy in hopping kangaroos.

1. A kangaroo hopping above a certain speed appears to consume less oxygen than a quadrupedal mammal, of similar weight, running at the same speed (Dawson & Taylor, 1973). This is thought to be achieved by storage of elastic energy in tendons and ligaments. 2. Energy can be stored in a tendon by stretching it, but only if the muscle fibres in series with it are stiff enough to resist most of the length change. We have measured length and tension changes in the contracting gastrocnemius muscle of the wallaby Thylogale during rapid, controlled stretches, and from this determined the amount of movement in muscle fibres and tendon (method of Morgan, 1977). 3. When the muscle was developing close to its maximum isometric tension, up to eight times as much movement occurred in the tendon as in the muscle fibres. This is made possible by the wallaby having a long and compliant tendon. 4. Measurement of work absorption by the muscle with a full length of free tendon and when the tendon had been shortened, showed that with the shortened tendon a larger proportion of movement occurred in the muscle fibres, producing a steep rise in work absorption by the muscle and a consequent increase in energy loss.

Animals↗

PubMedDate not supplied

Novel technique for the combined recovery, extraction and clean-up of forensic organic and inorganic trace explosives samples.

This paper describes a simple processing and analysis scheme for explosives trace swab samples which deals both with organic and inorganic materials. Swabs, wetted with ethanol or ethanol/water mixture, were extracted with ethanol/water mixture. The extract was passed directly through a simple column containing an acrylonitrile/styrene copolymer adsorbent. The adsorbent retained common organic explosives, which were recovered with an efficiency of 30-50% as a relatively clean ethyl acetate solution. The concentrated ethyl acetate eluate was analysed using gas chromatography with chemiluminescence or mass spectrometric detection. The unretained inorganic ions and sugars, which were recovered with generally high efficiency as an ethanol/water solution, could be directly analysed using ion chromatography and/or capillary electrophoresis. Minor difficulties encountered in the analysis of sugars, fluoride and phosphate were examined.

Chromatography, Gas↗

PubMedDate not supplied

Effects of perfluorochemical on phagocytic function of leukocytes.

Oxygen-carrying perfluorochemical emulsions may become useful for transfusions when red cells cannot be used. Since accumulation of perfluorochemicals in reticuloendothelial cells has been demonstrated, we tested the phagocytic function of monocytes and neutrophils in rabbit and human blood exposed in vivo and in vitro, respectively, to perfluorotributylamine (Oxypherol) a perfluorochemical blood substitute. Neutrophil and monocyte phagocytosis was assessed by determining the uptake of serum-coated fluorescent beads by monocytes and neutrophils in whole blood. Morphologic changes were assessed by electron microscopy. The phagocytic activity of monocytes and neutrophils in the blood of four rabbits injected 4 hours earlier with 70 to 85 ml of Oxypherol (28 ml/kg) was depressed by 87 +/- 1.0 percent. Neutrophils in this blood showed morphological alterations characterized by swelling and extensive vacuole formation. Similar changes were found in neutrophils and monocytes of human blood incubated with Oxypherol (10-50%, V/V) at 37 degrees C for 1 hour. The phagocytic activity of human neutrophils and monocytes exposed to 20 percent, V/V Oxypherol was depressed by 35 +/- 9.9 percent. We conclude that caution should be exercised when administering perfluorochemical blood substitutes in patients exposed or at risk of infection.

Animals↗

PubMedDate not supplied

Rapid temperature check for heat blocks.

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Blood Preservation↗

PubMedDate not supplied

CA 125--epitopes and molecular size.

CA 125 has two main immunogenic areas reactive with mouse and rat monoclonal antibodies. These areas are defined by the antibodies OC 125 and M11, respectively. Antibodies related to the main groups are named OC 125-like and M 11-like antibodies. The OC 125-like antibodies can be subgrouped into four sets, whereas the M 11-like antibodies segregate into many closely related binding specificities. One M 11-like antibody, ZR38, is not fully inhibited by any other M 11-like antibody and therefore represents a distinct subgroup. A single antibody, OV 197, is related to some OC 125-like antibodies, but not to OC 125. However, OC 125 enhances binding of OV 197 to its epitope. A new antibody, 7C 12, induces conformation changes, affecting binding of some M 11-like and some OC 125-like antibodies. CA 125 exists as very large molecules that can be partly disrupted by SDS and heat. The form found in serum might be a degradation product from a larger molecule found in the abdominal and other serous cavities.

Animals↗

PubMedDate not supplied

In vivo assessment of antiviral reactivity in chronic HIV infection.

PURPOSE AND METHOD: Chronic infection with HIV renders individuals incapable of mounting an effective host antiviral response, as defined by in vitro assays. Therefore, to determine whether antiviral reactivity could be detected in vivo, we interrupted effective antiviral treatment prospectively in nine chronically infected aviremic individuals. Low-dose interleukin-2 (IL-2) was administered before and after treatment interruption to compensate for any potential IL-2 production deficiency. In vivo antiviral reactivity was monitored subsequent to the interruption of antiviral therapy via viral and lymphocyte dynamics. The study was terminated when the plasma HIV RNA concentration reached a plateau, defined as four successive determinations that were <25% from the mean. RESULTS: Plasma viral relapse occurred in all participants; reaching a peak concentration within 2.5 weeks. However, over the subsequent 2 weeks viremia was reduced an order of magnitude coincident with a 2-fold lymphocytosis of the CD8 + T cell subset. A second treatment interruption resulted in attenuation of the peak and trough virus concentrations by <10-fold in 3 of 4 participants, while the CD8 + T cell concentrations remained elevated. CONCLUSION: These findings indicate that chronic HIV infection prior to successful antiviral therapy does not preclude host antiviral reactivity. In addition, in vivo antiviral reactivity as revealed by viral and lymphocyte dynamics after antiviral treatment interruption can be useful to monitor the efficacy of different therapies.

Antiretroviral Therapy, Highly Active↗

PubMedDate not supplied