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Biomedical subjects

D R Bailey

Publications and source records attributed to D R Bailey.

35 records · Page 2Linked to original sources

Effects of ultrasonography on the bovine testis and semen quality.

Ten yearling beef bulls were assigned to control (n = 5) or ultrasound treatment (n = 5) groups. Treatment consisted of a single 3-min exposure per testis to ultrasonic radiation at a frequency of 5 MHz and at low acoustical intensity (spatial peak temporal averages at 10 and 18 mm, focal points of 0.14 and 0.59 mW/cm(2) and spatial peak pulse averages of 1.1 and 3.4 W/cm(2) at corresponding focal points). Ultrasonic treatment had no effect (P > 0.05) on the percentage of progressively motile spermatozoa, primary sperm defects, secondary sperm defects or normal acrosomes over a 10-wk posttreatment evaluation period. Similarly, scrotal circumference, testicular consistency, paired testes weight, paired epididymal weight, daily sperm production per gram of testicular parenchuma, and epididymal sperm reserves were not affected (P > 0.05) at 69 d following ultrasound treatment. Ultrasonography of bovine scrotal contents did not affect reproductive capacity over the interval studied.

Journal Article↗

Growth and body composition of mice selected for high body weight.

To elucidate the influence of high body weight selection on body compositional relationships, the accumulation of lipid, protein, and ash was investigated in two lines of mice selected for high 42-day body weight (H lines) and an unselected foundation population (FP). The two H lines differed in population size and were designated as the high-large (HL) and high-small (HS) lines. Logistic body growth curves revealed that HL mice exhibited an accelerated growth rate and reached a higher mature body weight than FP or HS mice. Over the range of body weights examined, HL mice had more lipid, less protein, and less ash than FP or HS mice of the same sex and body weight. However, HL lipid accumulation (relative to body weight increase) was not accelerated in comparison to that of FP mice. This study suggests that the existing model of selection-mediated compositional changes requires expansion to account for the ability of high-growth selection to direct an acceleration of body growth without a correlated enhancement of the relative rate of fat accumulation.

Aging↗

Relationship of scrotal surface temperature measured by infrared thermography to subcutaneous and deep testicular temperature in the ram.

The right testis of 9 anaesthetized rams was removed from the parietal tunica vaginalis and replaced by a surrogate testis (water-filled balloon) through which water of known temperature was circulated. Thermistors were inserted in the surrogate testis, between the scrotal skin and parietal tunica vaginalis on the right side, and deep within the intact left testis. Scrotal surface temperatures over the surrogate and intact testes were measured by infrared thermography. Scrotal surface temperature was correlated (P less than 0.01) with both subcutaneous (r = 0.95) and surrogate (r = 0.91) testicular temperature. The temperature differential between scrotal surface (30.1 +/- 0.1 degrees C) and deep testicular temperature over the intact side (34.9 +/- 0.09 degrees C) was 4.8 degrees C at an ambient temperature between 24.0 and 26.6 degrees C. Contact with the scrotal skin is not required to measure scrotal surface temperature by infrared thermography. This, coupled with the close association between scrotal surface temperature and that of underlying structures, will enhance our ability to understand better testicular temperature regulation and scrotal/testicular function.

Animals↗

The renin--angiotensin--aldosterone system during cardiac surgery with morphine--nitrous oxide anesthesia.

Ten consecutive adult patients undergoing elective cardiac surgery with extracorporeal circulation were anesthetized using morphine (1-3 mg/kg) and nitrous oxide. Pre-bypass plasma renin activity showed a 3.5-fold elevation (P smaller than 0.001) over baseline values. This correlated with maximal blood pressure elevation. Plasma renin activity remained elevated during bypass. High baseline aldosterone levels increased 3.4-fold (P smaller than 0.001) after 15 minutes on bypass and 4.0-fold by the end of bypass. Plasma potassium decreased from 3.9 mEq/1 before bypass to 3.2 mEq/1 (P smaller 0.0001) during bypass, and the fractional urinary excretion of potassium was 32 per cent before bypass with a mean of 34.4 per cent during bypass. Urinary output remained high during bypass despite a progressive decrease in glomerular filtration rate. Catecholamine levels showed no significant change. The data suggest that the renin-angiotensin-aldosterone system may play a role in blood pressure regulation during cardiopulmonary bypass and may result in the excessive urinary excretion of potassium and decrease in plasma potassium levels.

Anesthesia, Inhalation↗

Effect of metrifonate on blood cholinesterases in children during the treatment of schistosomiasis.

In a controlled clinical trial, Tanzanian schoolchildren with urinary schistosomiasis, many of whom had coexisting hookworm infection, were randomly allocated to one of three groups that were treated with doses of 7.5, 10.0, and 12.5 mg per kg of body weight, respectively, of metrifonate, orally, up to 3 times at 14-day intervals. No serious side effects were observed during or after the administration of single or repeated doses. A few hours after medication, plasma cholinesterase was almost completely inhibited, regardless of the dose given, while erythrocyte cholinesterase was almost completely inhibited, regardless of the dose given, while erythrocyte cholinesterase was inhibited down to 40-60% of the pretreatment level, depending on the dose. Plasma cholinesterase was inhibited to a greater extent than erythrocyte cholinesterase but showed a more rapid recovery of activity. A moderate accumulation of unreactivated erythrocyte cholinesterase occurred at all dose levels with this regime. Four weeks after the last dose of drug, plasma cholinesterase activity was nearly normal in all the treated children. Erythrocyte cholinesterase activity returned to normal 8-15 weeks after the last dose. The therapeutic results confirmed the efficacy of metrifonate against Schistosoma haematobium. There was an additional though less striking effect against hookworm.

Adolescent↗

The effect of salt medicated with diethylcarbamazine in bancroftian filariasis.

The paper describes a trial conducted in Tanzania of the effect on bancroftian microfilaraemia of common salt medicated with diethylcarbamazine at a 0.1% (w/w) concentration, when given to a closed population of 600-700 with a known salt intake.After good observer agreement in microfilarial counting had been demonstrated, quantitative blood surveys were performed monthly on known carriers. Paired pretreatment microfilarial counts from the same patients at an interval of 4 months suggested a natural fluctuation in microfilarial densities and emphasized the need for parallel concurrent controls during treatment.During the trial the mean microfilarial densities fell steadily, being reduced by 73% at 3 months and 90% after 6 months. Tolerance to the drug-salt mixture was extremely good.Problems of planning, salt preparation and assessment of results are discussed and the importance of correct experimental design in future trials is stressed. The authors suggest that a trial of salt containing 0.2% (w/w) diethylcarbamazine may achieve optimum results. They point out that, while the use of diethylcarbamazine-medicated salt may prove useful in reducing transmission in closed communities or in endemic areas with no alternative source of salt, its extension to national populations as a sole means of bancroftian filariasis control would be of problematical value.

Diethylcarbamazine↗

Metrifonate in urinary schistosomiasis.

This paper describes the effect of oral metrifonate, an organophosphorus cholinesterase inhibitor, on Schistosoma haematobium infections.The methodology of initial studies in hospital patients and 3 field trials in schoolchildren, using spaced doses ranging from 5 mg to 15 mg per kg of body-weight is detailed.The expected fall in plasma cholinesterase was confirmed. No major side-effects were encountered and minor symptoms were associated with high doses only.The optimum dose was 7.5 mg per kg, given once every 14 days or once monthly to a maximum of 3 doses if necessary. About two-thirds of patients were cured after 1 or 2 doses, but some 10% of these relapsed within 6 months of treatment. In 2 trials of this dose, cure rates of 71% and 79% were obtained.The authors conclude that metrifonate is a useful addition to oral schistosomicides for the treatment of S. haematobium infections in children, but suggest that more trials with spaced dose regimes are indicated and that further experimental studies are needed to define its mode of action.

Child↗

A comparative study of enflurane and halothane using systolic time intervals.

The effects of enflurane and halothane anesthesia on systolic time intervals were studied in 12 healthy patients. Cardiovascular measurements were made at equipotent levels of anesthesia: enflurane 1.23% end-tidal and halothane 0.65% end-tidal. These agents were studied first with 50% N2O and then without N2O. Systolic, diastolic, and mean arterial blood pressure were decreased more by enflurane than by halothane (p less than 0.05). However, halothane caused significantly more myocardial depression than enflurane, as indicated by a larger preejection period (PEP) and preejection period/left ventricular ejection time (PEP/LVET) and a smaller 1/PEP2 and ejection fraction. When N2O was discontinued, both agents increased PEP and PEP/LVET and decreased 1/PEP2 and the ejection fraction.

Adult↗

Distal push splint.

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Activator Appliances↗