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Biomedical subjects

J E Wallace

Publications and source records attributed to J E Wallace.

At least 37 records · Page 2Linked to original sources
PubMed1983

Thermal and photolytic degradation studies of promethazine hydrochloride: a stability-indicating assay.

A stability-indicating GLC method for the analysis of promethazine hydrochloride in polyethylene glycol delivery systems is reported. This method is capable of distinguishing the intact drug from its thermal and photodegradation products. A linear relationship between peak height ratio (promethazine-promazine) and promethazine concentration is found up to a concentration of 600 micrograms/ml. Kinetic studies were performed to determine the photolytic and thermal degradation rates of promethazine hydrochloride as a function of pH. The activation energies at pH 2.98, 3.94, and 5.12 were obtained from linear Arrhenius plots and were found to be 6601, 5888, 5570 cal/mole, respectively. The first-order rate constant increased with increasing pH. The photolytic degradation of promethazine hydrochloride does not follow simple first-order kinetics.

Chromatography, Gas↗
PubMed1983

Ethanol acceptance as a function of genotype amounts of brain [Met]enkephalin.

Our results indicate a negative correlation between the amount of ethanol (10%) consumed and endogenous levels of brain [Met]enkephalin in C57BL/6J (alcohol-preferring) and DBA/2J (alcohol-nonpreferring) inbred mice strains. Additionally, it was found that 8 wk after 1-day starved groups of both C57BL/6J and DBA/2J mice were challenged with ethanol (10%) for 1-day acceptance, they had significantly lower levels of brain [Met]enkephalin compared with their nonalcohol-treated controls. These results suggest that the brain endogenous peptidyl opiates may play a crucial role in alcohol-seeking behavior.

Alcoholism↗
PubMed1983

Anticonformity aspects of depression in mild depressive states.

Controversial issues regarding the relation of conformity and anticonformity variants of dependency to depression and self-esteem were examined. The Willis-Hollander model of social influence and an experimental paradigm which permits differentiation of dependency responses into conformity and anticonformity subcategories were used. Ninety female college students who had been given the Beck Depression Inventory and a measure of self-esteem engaged in a perceptual judgment task, with two degrees of social influence. Depression and self-esteem were unrelated to independence and conformity. The main finding in the step-wise regression analyses was that depression was significantly related (p less than .001) to the anticonformity variant of dependency. The assumption that depression is related to dependency was supported, but the conventional position that such dependency consists of the conforming variant, involving compliance and approval- and guidance-seeking, was not supported, at least within the range of depression sampled.

Adolescent↗
PubMed1982

Effect of vitamin D2 on the assay of 24,25-dihydroxyvitamin D3 in man.

Serum levels of the dihydroxylated metabolite of vitamin D3, 24,25-dihydroxycholecalciferol (24, 25(OH)2D3) were measured by competitive protein-binding assay in 2 anephric patients while undergoing therapy with 25-hydroxycholecalciferol (25(OH)D3) and, at a later date, vitamin D2, ergocalciferol. Whereas there was no increase in serum levels of 24, 25 (OH)2D3 when the patients were treated with 25 (OH)D3, a significant increase was apparently seen when vitamin D2 was given. These results suggest that a metabolite of vitamin D2, non-renal in origin, may be interfering in the assay for 24, 25 (OH)2D3. The different levels of serum 24, 25 (OH)2D3 in anephric man found by various groups of workers are explained by these results.

24,25-Dihydroxyvitamin D 3↗
PubMed1981

Determination of promethazine in serum by liquid chromatography.

We describe a procedure for the liquid-chromatographic determination of promethazine in low-nanogram concentrations in serum. Triflupromazine is used as the internal standard. The method is based on a single extraction of promethazine from serum with hexane and subsequent derivatization with trichloroethyl chloroformate. Analytical recovery of promethazine is about 90%. The lower limit of detection is 1 microgram/L when a 2.0-mL aliquot of serum is assayed. Our data illustrate the practicability of the method for bioavailability studies after oral or rectal administration of promethazine hydrochloride.

Administration, Oral↗
PubMed1980

Animal models of declining memory in the aged: short-term and spatial memory in the aged rat.

Short-term and spatial memory were studied in Fischer 344 rats ranging in age from 6 to 26 months of age. Spatial memory, as measured by performance in an 8-armed radial maze, declined gradually with age. In contrast, short-term memory, as measured by retention of previous choices in the spatial maze over short intervals and performance on a modified form of Konorski's discriminated delayed response task, did not decline differentially as a function of age. These findings may be comparable to those obtained in the aged human, who also show marked deficits in spatial memory and little change in primary memory under appropriate test conditions.

Aging↗
PubMed1980

Motor and reflexive behavior in the aging rat.

Four age groups of Fischer 344 rats (6-, 12-, 18-, and 24-months of age) were compared on a battery of reflexive and locomotor tasks. The simple reflexive tasks such as placing, hopping, negative geotaxis and surface and mid-air righting showed little or no change as a function of age. In contrast, tasks requiring more coordinated control of motor and reflexive responses such as suspension from a horizontal wire, descent of a wire mesh pole, traversal of an elevated platform and rotorod performance showed significant declines with age, with some declines noticeable early in the lifespan. When these results are compared with the results of tasks conducted with infant rats, it is noted that the reflexive and motor skills that emerge early in development are the least affected by the aging process. This observation suggests a first-in, last-out sequence for reflexive and motor behaviors.

Aging↗
PubMed1980

Evaluation of an enzyme immunoassay for determining diazepam and nordiazepam in serum and urine.

We evaluated a commercially available enzyme immunoassay method for determining the concentration of total diazepam plus its active metabolite, nordiazepam, in small amounts of serum and urine. The coefficients of variation were 5% within assay and 8% between assay. Concentrations so measured for patients' sera correlated well with those obtained both by gas chromatography with electron-capture detection and by liquid chromatography with ultraviolet detection. For urine samples, the correlation between values obtained by the enzyme immunoassay method and those for total diazepam/nordiazepam/oxazepam obtained by liquid chromatography was adequate for routine clinical toxicological use. The ability of the immunoassay to determine other benzodiazepines was also evaluated.

Chromatography, High Pressure Liquid↗
PubMed1979

Tuberculosis.

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England↗
PubMed1979

1,25-Dihydroxycholecalciferol in human serum and its relationship with other metabolites of vitamin D-3.

A competitive protein binding assay for 1,25-dihydroxycholecalciferol has been developed using the hormone's nuclear receptor protein from chick intestinal mucosa. This nuclear receptor protein can be stored at -70 degrees C for several months and bound and free hormone can be separated easily with dextran coated charcoal. Results obtained using this assay agree well with those reported by other groups of workers. Serum levels of other vitamin D-3 metabolites, namely 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol have also been measured and are shown in relation to 1,25-(OH)2D3 levels.

Animals↗
PubMed1979

Emotional disturbance and cognitive deficits in hyperthyroidism.

Assessment of cognitive and emotional variables in 19 females with hyperthyroidism was made pretreatment, at 3 weeks, and after euthyroidism was established. A matched group of normal controls was similarly tested. Group differences on cognitive measures did not reach statistical significance, but cognitive deficits and symptoms of emotional disorder were significantly associated with the severity of thyroid toxicity previous to treatment. Measures of cognitive function and personality features moved towards control group values as euthyroidism was established. The implication of these findings is discussed in the context of a review of previous literature. The observed cognitive disturbance and emotional distress appear to be reflections of thyroid toxicity.

Age Factors↗
PubMed1979

Analysis for diazepam and nordiazepam by electron-capture gas chromatography and by liquid chromatography.

We describe the use of electron-capture gas chromatography or reversed-phase "high-performance" liquid chromatography for concurrent analysis for diazepam and nordiazepam in serum. In the gas-chromatographic analysis our use of a new chemically deactivated stationary liquid phase, SP 2250-DB (Supelco, Inc.), resulted in improved chromatographic sensitivity and peak symmetry for the two benzodiazepines as compared to that obtained with either OV-17or OV-1 phases. Steady-state concentrations of diazepam and nordiazepam in serum as determined by gas-liquid chromatography correlated closely with those found by liquid-liquid chromatography.

Chromatography, Gas↗