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D A King

Publications and source records attributed to D A King.

12 recordsLinked to original sources
PubMed1991

The neuropsychology of depression in the elderly: a comparative study of normal aging and Alzheimer's disease.

The neuropsychological testing of 23 elderly depressed patients was compared to that of 23 healthy controls and 20 Alzheimer's disease (AD) patients. Depressed subjects were deficient relative to controls on most tasks, including naming and cued memory. There was a greater negative influence of age on the performance of depressed subjects (relative to controls) on some tasks. Despite their significant deficits, depressed patients were clearly distinguishable from AD patients. It is suggested that the combined effects of age and depression produce a pattern of deficits that is distinct from that of younger depressives, but less severe than that of Alzheimer's patients.

Aged↗
PubMed1989

Lack of evidence for aromatase in human prostatic tissues: effects of 4-hydroxyandrostenedione and other inhibitors on androgen metabolism.

The effects of 4-hydroxyandrostenedione (4-OHA) and other aromatase inhibitors, 10-propargylestr-4-ene-3,17-dione and imidazo[1,5-alpha]-3,4,5,6-tetrahydropyrin-6-yl-(4-benzonitrile), as well as 5 alpha-reductase inhibitors N,N-diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane-17 beta-carboxyamide and 4-methyl-3-oxo-4-aza-androsta-5-ene-17-ol were investigated in prostatic tissue from six patients with benign prostatic hypertrophy and seven patients with prostatic cancer, and from normal men at autopsy. We attempted to measure aromatase activity in the tissue incubations by quantitating 3H2O released from androstenedione or testosterone labeled at the C-1 position. High performance liquid chromatography and thin layer chromatography were used to isolate steroid products. Although the amount of 3H2O released was at least twice that of the heat-inactivated tissue samples, no estrone or estradiol was detected on high performance liquid chromatography. The 3H2O release was significantly inhibited by 4-OHA and N,N-diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane-17 beta-carboxyamide, but not by the other aromatase inhibitors. 4-OHA also inhibited 5 alpha-reductase in both benign prostatic hypertrophy and cancer tissue, although to a lesser extent than N,N-diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane-17 beta-carboxyamide. The other aromatase inhibitors were without effect on 5 alpha-reductase. Our results indicate that 3H2O released from [1 beta-3H]androstenedione and [1,2,6,7-3H]androstenedione does not correlate with estrogen formation and may be the result of other metabolic reactions. Although it appears that the prostate lacks aromatase, 4-OHA may be of benefit in patients with benign prostatic hypertrophy or prostatic cancer by inhibiting this enzyme in peripheral tissue.

Androstenedione↗
PubMed1989

Tolerance to ethanol's disruptive effects on operant behavior in rats.

The effects of pre-session and post-session daily ethanol injections on the development and loss of tolerance to ethanol's effects on fixed ratio operant performance in rats was assessed using a cumulative dosing procedure. Daily pre-session ethanol administration produced a greater decrease in ethanol sensitivity than did daily post-session ethanol. Both tolerance effects persisted for at least 1 month after the chronic injection phase. No changes in ethanol sensitivity were apparent in the saline control group and no changes in estimated blood ethanol levels were found after the chronic treatments. The post-session ethanol groups displayed a performance decrement during the initial segment of the chronic injection period, but improved significantly across the chronic phase. These data suggest that some delayed effect of ethanol initially impaired performance but that tolerance to this ethanol effect also occurred and probably contributed to the decline in ethanol sensitivity seen in these groups. Compensatory learning as the mechanism for tolerance development in the pre-session and post-session ethanol groups was supported by the finding of no change in ethanol sensitivity in rats exposed to comparable daily ethanol without any concurrent operant task on which the direct, immediate, or indirect, delayed ethanol effects could operate.

Animals↗
PubMed1989

Parallel development of ethanol tolerance and operant compensatory behaviors in rats.

This experiment was designed to detect compensatory learning that has been suggested to occur during the course of tolerance development to ethanol's effects on operant performance. The effects of presession ethanol injections on the development of tolerance to ethanol's effects on operant performance in an afternoon Fixed-Ratio (FR) task was assessed in rats that were concurrently performing in a morning DRL task. Only presession saline injections were administered for the DRL task. A cumulative dosing procedure was used to establish initial and postethanol exposure dose-effect curves for both tasks. Daily presession ethanol administration produced a 3-fold shift-to-the-right in the dose-effect curve for FR-task performance. No changes were evident in the FR-task performance of controls that received daily saline injections. However, during the period of daily ethanol injections and during subsequent cumulative dose tests, the ethanol, but not the control, group displayed dose-related increases in total DRL-task responses relative to baseline. These DRL data were interpreted as reflecting the development of rate-increasing behaviors that compensated for and contributed to the tolerance of ethanol's rate-decreasing effects on FR-task performance.

Animals↗
PubMed1987

Associative control of tolerance to the sedative effects of a short-acting benzodiazepine.

The role of Pavlovian conditioning in tolerance to the depressant effect of a benzodiazepine (midazolam) on the ambulatory activity of rats was examined. The depression of activity by low doses (1.0 and 4.0 mg/kg, ip) of midazolam diminished quickly over repeated doses given at 48-hr intervals (Experiment 1). Equivalent tolerance was observed in groups measured at 2 min and 30 min after drug injection. When challenged with saline, however, drug-tolerant animals tested immediately after injection were hyperactive in comparison with nontolerant controls, whereas equivalent groups tested 30 min after injection were not. A second context was designed, and its discriminability from the original was established by assessing context-specific suppression of activity following exposure to mild electric shock (Experiment 2). In Experiment 3A, although tolerant animals tested in the drug-associated context remained fully tolerant, a second group demonstrated a complete loss of tolerance when given the drug in a saline-associated context. Both groups were fully tolerant when tested again in the drug-associated context after 14 drug-free days. In Experiment 3B, tolerance was significantly reduced by 14 extinction exposures to the drug-associated environment without the drug. These results are uniquely predicted by associative models of drug tolerance and may have implications for the clinical use of this class of drugs.

Animals↗
PubMed1976

The effect of oral physiotherapy on dilantin gingival hyperplasia.

Gingival hyperplasia was studied in 13 boys with epilepsy living in a state hospital. Boys were selected on the basis of having gingival hyperplasia, having all teeth between cuspids (upper and lower), having no occlusal abnormality and being cooperative. After gingivectomy, regrowth of gingiva was compared around lateral incisors on one side of the mouth having operator-assisted oral hygiene with that around lateral incisors on the other side of the mouth without operator-assisted oral hygiene. Regrowth of tissue was documented by precise photogrammetry. Oral hygiene, gingival inflammation and crevicular fluid were monitored. Less inflammation, less crevicular fluid and less regrowth of gingival tissues occurred around teeth subjected to good oral hygiene. Precise periodic photographic documentation of the clinical status of patients during studies such as this is considered very valuable.

Adolescent↗
PubMedDate not supplied

Role of context in ethanol tolerance and subsequent hedonic effects.

Two groups of male Sprague-Dawley rats received ethanol dose-effect tests for FR30, food-reinforced operant performance, in each of two environmental contexts, before and after a period of daily presession ethanol or saline injections. During the latter period, context alternated daily. The ethanol group received ethanol prior to sessions for one context and saline, prior to sessions for the other context. The saline group always received presession saline. The ethanol, but not the saline, group displayed robust tolerance to ethanol's rate-decreasing effects, with no difference between tests in each context. Both groups then received training and testing in an ethanol-conditioned place preference task. The saline group displayed significant avoidance of the compartment paired with ethanol. The ethanol group displayed no initial aversion for the ethanol compartment and, with extended conditioning, showed a significant increase in time spent in the ethanol compartment. We suggest that this tolerance represents context-independent, learning to compensate for ethanol-induced effects, and that this tolerance subsequently blocked the conditioned place aversion evident in nontolerant controls, thereby enhancing the estimates of ethanol's reward properties.

Animals↗