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Biomedical subjects

G L Sprague

Publications and source records attributed to G L Sprague.

22 records · Page 2Linked to original sources
PubMed1976

Control of ethanol withdrawal symptoms in mice by phenytoin.

Mice were made physically dependent upon ethanol using either of two methods which involved ethanol vapor inhalation. Following the cessation of exposure to ethanol, the severity of handling-induced convulsions and changes in the response to an electric foot shock (startle reflex) were recorded. Animals given isotonic saline or propylene glycol:ethanol vehicle during withdrawal exhibited handling-induced convulsions, and ethanol (2.0-4.0 g/kg) or phenytoin (5-20 mg/kg) administration during withdrawal resulted in a reduction in the severity of these convulsions. A reduced startle reflex threshold was also evident during withdrawal in mice given isotonic saline or propylene glycol:ethanol vehicle. Ethanol (0.5-4.0 g/kg) or phenytoin (10-20 mg/kg) administration during withdrawal resulted in a significant elevation of the startle reflex threshold compared to control animals. The results are discussed as they relate to others obtained in experimental and clinical studies.

Animals↗
PubMedDate not supplied

Effect of multiple diisopropyl fluorophosphate injections in hens: a behavioral, biochemical, and histological investigation.

Delayed neurotoxicity after acute administration of organophosphates to hens can be predicted by using the neurotoxic esterase (NTE) assay. The present study was designed to compare results obtained with the assay after single or multiple diisopropyl fluorophosphate (DFP) injections in hens. Adult White Leghorn hens were given DFP in a single (1.0 mg/kg) or in multiple (0.05 mg/kg . d for 20 d) sc injections. Walking behavior was measured and both groups showed significant impairment by d 5 after the first or only DFP injection. However, impairment at the end of the study was greater in hens given a single injection of 1.0 mg/Kg. All DFP-treated hens exhibited axonal degeneration in brains, spinal cords, and peripheral nerves, and the changes in the two groups were of equal severity. Cervical and thoracic spinal cord lesions in hens given multiple DFP injections appeared to be primarily restricted to the myelinated spinocerebellar tracts. Inhibition of NTE was measured in brains, spinal cords, ilea, and thymuses 24 h after the single injection of 1.0 mg/kg DFP or after the 20th injection of 0.05 mg/kg DFP in additional hens. The NTE inhibition was significantly greater in all four tissues in the group given DFP as a single treatment. NTE in nerve and nonnerve tissues appeared to be differentially affected by single and multiple DFP treatments. Walking impairment and NTE inhibition were more marked when DFP was given in a single rather than 20 daily injections. However, in hens given multiple DFP injections the severity of central and peripheral nerve lesions was greater than was expected from the clinical and biochemical results.

Animals↗
PubMedDate not supplied

Critical neurohistopathologic evaluation of clinically healthy commercial single-comb White Leghorn hens.

A neurohistopathologic study was conducted to determine the types and incidence of spontaneous lesions of the nervous system in healthy adult hens. Tissues examined were brain, three levels of spinal cord, and sciatic nerves from 92 healthy commercial hens from a single commercial egg-production flock judged above average in health. These hens represented negative controls (untreated or given corn oil) in 9 separate toxicologic studies. Minimal to mild focal proliferative or degenerative microscopic changes were detected at all levels of the nervous system. More than 50% of the hens had lymphocytic perivascular cuffing and focal gliosis in the central nervous system. Similarly, lymphocytic foci (in nerve sheaths or within fasciculi) and Schwann cell hyperplasia were commonly seen in sciatic nerves. The spinal cord exhibited neuronal swelling and chromatolysis frequently; axonal degeneration (in brain and spinal cord) and swelling or degeneration of nerve fibers in sciatic nerves were observed sporadically. Most changes were rare or mild. A few chickens had mild or moderately severe perivascular cuffing and focal gliosis. The significance of these findings is discussed in relation to the use of the adult hen in neurotoxicologic evaluations.

Animals↗