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Biomedical subjects

G I Scott

Publications and source records attributed to G I Scott.

13 recordsLinked to original sources

The effect of certain intrinsic and extrinsic variables on the acute toxicity of selected organophosphorus insecticides to the mummichog, Fundulus heteroclitus.

The acute toxicity of two organophosphorus (OP) insecticides, azinphosmethyl and acephate, was evaluated in the mummichog, Fundulus heteroclitus. In addition, the effects of certain intrinsic (sex) and extrinsic (salinity and multiple toxicant interraction) variables on the toxic response were also investigated. Azinphosmethyl was by far the most toxic of the two OP insecticides with a 96h LC50 approximately 100,000 x lower than that for acephate. Slight sex differences were observed in the sensitivity of mummichogs to each of the OP insecticides with male fish being marginally more sensitive. Significant effects of low salinity stress were observed only with acephate exposure and, in this case, low salinity appeared to be slightly protective. In general, all of the insecticide mixtures (azinphosmethyl/endosulfan, azinphosmethyl/fenvalerate and acephate/fenvalerate) tested exhibited simple additive toxicity.

Animals

Vas cannulation with implanted sperm reservoirs for obstructive azoospermia or ejaculatory failure.

Seven patients with azoospermia due to obstruction of the abdominal part of the vas deferens, and five paraplegic men with ejaculatory failure, were treated with implanted sperm reservoirs. In eight patients (67%) motile spermatozoa were recovered. Two pregnancies (17%) were achieved with subsequent live births (by AIH). In two patients the fertilising capacity of the spermatozoa was unsuccessful as assessed by IVF. Infection required the removal of two reservoirs.

Catheterization

Lethal and sublethal effects of chlorine, phenol, and chlorine-phenol mixtures on the mud crab, Panopeus herbstii.

The mud crab, Panopeus herbstii, was acutely exposed (96-hr) to chlorine-produced oxidants (CPO), phenol, and a CPO-phenolic mixture (1:1) to determine lethal and sublethal effects. The 96-hr (LC50) values were determined for each individual compound and mixture. Additionally, whole-animal respiration rates were measured following acute exposure to sublethal concentrations of each compound or mixture. Phenol uptake/depuration rates were measured in the phenol and CPO-phenol mixture concentrations. Results indicated 96-hr LC50 values of 1.06 mg/L for CPO (fiducial limits (FL) = 0.53-2.01 mg/L), 52.8 mg/L for phenol (FL = 45.6-64.5 mg/L), and 184.7 mg/L total toxicant units (TTU) for the CPO-phenol mixture (FL = 143.7-250.2 mg/L TTU). Statistical analysis indicated that the acute toxicity of the CPO-phenol mixture was less than additive. Sublethal studies indicated that only acute exposure to sublethal concentrations of CPO caused altered respiration rates. After 96-hr depuration, metabolic rates in all CPO-exposure crabs generally returned to control rates. Uptake/depuration rate studies indicated significantly lower phenol uptake rates in crabs exposed to the CPO-phenol mixture. These findings suggest that the less-than-additive toxicity of the CPO-phenol mixture may result from lowered uptake/depuration rate kinetics and indicate that the discharge of chlorinated-phenolic waste may not result in additive and/or synergistic interactions, but rather in less-than-additive effects on decapod aquatic species.

Animals

A double-blind controlled trial of a new alpha-1 blocking drug in the treatment of bladder outflow obstruction.

Thirty-one patients with urodynamically proven bladder outflow obstruction were treated with Alfuzosin in a 3-month, double-blind, placebo-controlled study. The irritative symptoms of bladder outflow obstruction were improved significantly in the treatment group, according to both objective and subjective evaluation. There was no objective evidence of a reduction in outflow resistance or obstruction in either group.

Adult