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Biomedical subjects

M Davidson

Publications and source records attributed to M Davidson.

At least 289 records · Page 16Linked to original sources
PubMed1989

Premorbid sociosexual functioning and long-term outcome in schizophrenia.

Chronic schizophrenic patients with the most severe social deterioration have been shown to differ from other chronic schizophrenic patients with respect to measures of left-to-right ventricular asymmetry, negative symptoms, and response to haloperidol treatment. In the current study, the authors investigated the social antecedents of these characteristics of very poor outcome schizophrenia in 69 chronic schizophrenic patients. Poor premorbid sociosexual functioning was associated with more severe left-to-right ventricular asymmetry, greater severity of negative symptoms, fewer positive symptoms, and worse current social functioning. These data suggest that factors associated with severe social deterioration in the end stage of schizophrenia are also associated with premorbid sociosexual impairment.

Adult↗
PubMed1989

The profit ward.

Explore the source record for details and available documents.

Commerce↗
PubMed1989

Pituitary--adrenal response to capture in Cayo Santiago--derived group M rhesus monkeys.

113 rhesus monkeys, representing 4 age classes, 3 matrilines, and immigrant adult males in a 161-member Cayo Santiago-derived troop living in a 2-acre enclosure, were sampled for levels of plasma ACTH and cortisol during a period of capture and brief cage confinement for routine veterinary examination. ACTH levels showed significant decreases over initially high values following capture in all subjects except infants, whereas cortisol levels remained elevated throughout the sampling period. Members of the lowest-ranking matriline had significantly higher ACTH levels than members of the other matrilines and immigrant males. Infants and juveniles exhibited higher cortisol levels than adolescent and adult monkeys. The overall pattern of results was generally consistent with previous findings from laboratory studies, providing not only evidence of generality across conditions and subject populations but also the basis for more detailed subsequent analyses of the relationship between pituitary-adrenocortical responsiveness, behavioral response to challenge, and age-sex-dominance status in wild-born rhesus monkeys.

Academies and Institutes↗
PubMed1989

Combined administration of physostigmine and clonidine to patients with dementia of the Alzheimer type: a pilot safety study.

Reports of cholinergic and noradrenergic deficits in brain specimens from Alzheimer patients have suggested that concomitant augmentation of cholinergic and noradrenergic neurotransmission can benefit some dementia of the Alzheimer type (DAT) patients. However, pharmacological agents that enhance central cholinergic and noradrenergic neurotransmission, like physostigmine and clonidine, might have serious adverse effects. Therefore, prior to the commitment of major resources in efficacy studies, feasibility pilot studies are necessary to ensure that physostigmine and clonidine, combined, can be safely administered to DAT patients. Physostigmine, 2 mg every 2 h, and clonidine, up to 0.3 mg/day, were tolerated by the nine DAT patients without clinically meaningful adverse effects.

Aged↗
PubMed1989

Evaluation of dressing protocols that reduce peritoneal dialysis catheter exit site infections.

Exit site infections (ESIs) remain a major complication of peritoneal dialysis (PD). This study was designed to evaluate various catheter care techniques that would decrease ESIs during the 3 months following catheter implantation. Factors that affect wound healing were studied by evaluating preoperative and postoperative variables, skin cleansing agents, and three types of dressings. A 40% reduction in ESIs occurred following implementation of a new protocol that was developed from the knowledge acquired after studying the catheter care protocols.

Bandages↗
PubMed1988

Ethanol increases synaptosomal free calcium concentration.

The effect of ethanol on synaptosomal free calcium concentration [( Ca2+]i) and 45Ca2+ uptake was studied in vitro. Synaptosomes were prepared from forebrains of adult rats and incubated in the presence of ethanol 50-500 mM. [Ca2+]i determined by means of the Ca2+-sensitive dye, fura-2, was increased by ethanol in polarized and depolarized synaptosomes, whereas 45Ca2+ uptake was decreased. The results suggest that ethanol may influence neuronal calcium homeostasis by increasing rather than decreasing [Ca2+]i.

Animals↗
PubMed1988

4-Aminopyridine in the treatment of Alzheimer's disease.

The cognitive and behavioral effect of 4-aminopyridine (4-AP) was examined in Alzheimer's disease (AD) using a dose finding/replication study design. Fourteen inpatients, aged 54-89 years (mean 66.1 +/- 10.6 SD), meeting NINCDS criteria for probable AD, were studied. Three doses of 4-AP--2.5 mg b.i.d., 5 mg b.i.d., and 10 mg b.i.d.--or placebo were administered for 4 consecutive days in random order. Symptomatic assessment was performed on the fourth day of each condition using the Alzheimer Disease Assessment Scale (ADAS). Thereafter, the dose on which the best performance occurred was readministered, as was placebo. Of the 13 patients who completed the dose-finding phase, 7 patients had at least one dose of 4-AP that was associated with less severe symptoms than was placebo, and those patients were included in the replication phase. Results indicated no significant difference in total ADAS scores (p greater than 0.05). Examination of the ADAS subscales revealed no significant 4-AP effect on any particular symptom. Possible explanations of the lack of a drug effect in this study include the unselective release of neurotransmitters by 4-AP, poor penetration into the central nervous system (CNS), and the presenile onset of the disease in these patients.

4-Aminopyridine↗
PubMed1988

Memory impairment in schizophrenic patients with tardive dyskinesia.

Memory functioning was contrasted in 40 schizophrenic patients with and without tardive dyskinesia (TD). Visual and verbal memory tests were used to investigate specific types of impairments. The presence of TD was ascertained using the Abnormal Involuntary Movement Scale (AIMS). TD patients scored significantly lower than non-TD patients on two measures of visual learning, though no differences were found for verbal learning or immediate recall. These results are consistent with previous reports that schizophrenic patients with TD demonstrate impaired cognitive functioning. They also raise the possibility that the neurochemical and structural changes underlying TD may produce specific deficits in memory for visual materials. In addition, a significant relationship was found between total score on the Brief Psychiatric Rating Scale (BPRS) and performance on all of the test measures included in the cognitive test battery. This demonstrates the importance of attending to the overall level of schizophrenic symptomatology when evaluating results from experimental learning tasks.

Dyskinesia, Drug-Induced↗
PubMed1988

A comparison of plasma homovanillic acid concentrations in schizophrenic patients and normal controls.

Plasma homovanillic acid concentrations, a potential index of central dopamine turnover, were examined in normal control subjects and chronic schizophrenic patients over a 12-hour period, including the period of sleep. Plasma homovanillic acid concentrations were lower in schizophrenic patients compared with normal controls at all times; however, within the group of schizophrenics, the more symptomatic patients had higher plasma homovanillic acid concentrations than the less severely ill patients. These data are consistent with a more complex role of dopamine in schizophrenia than was previously conceptualized.

Adult↗
PubMed1988

Platelet alpha 2-adrenergic receptor function in psychiatric disorders.

The inhibitory effects of norepinephrine (NE) on the cyclic adenosine-3',5'-monophosphate (cAMP) response to prostaglandin E1 (PGE1), a measure of alpha 2-adrenergic receptor function, have been compared in platelets from drug-free schizophrenic patients, depressive patients, and normal controls. The absolute value of the inhibition by NE of the cAMP response to PGE1 was smaller in platelets from schizophrenic and depressive patients than in controls. However, this result was secondary to the smaller baseline platelet cAMP response to PGE1 in patients with these disorders. Effects of NE on cAMP production did not discriminate between actively ill and remitted patients with either schizophrenia or depression. Platelet alpha 2-receptor sensitivity, as measured by the effects of NE on cAMP production, does not appear to be altered in these psychiatric disorders.

Adult↗
PubMed1988

Microbiological and clinical significance of a new property of defective lysis in clinical strains of pneumococci.

A pneumococcal isolate that caused relapsing meningitis in a patient infected with human immunodeficiency virus (HIV) was found to display an unusual response to penicillin--rapid death but a striking lack of cellular lysis. This lytic defect was also detected in all four pneumococcal isolates from three additional HIV-infected patients and in more than half of the clinical isolates from patients with bacteremia. In a rabbit model of meningitis, the lysis-defective strain remained cryptic, with a delay of 5 h in the onset of leukocytosis in cerebrospinal fluid. A marked burst of leukocytosis was associated with ampicillin-induced lysis of a lysis-sensitive strain but not of a lysis-defective strain. Pneumococcal clinical isolates have different lytic responses to penicillin; defective lysis may adversely affect the course of meningitis, an observation suggesting that autolysins play a role in modulating infectious diseases.

Acquired Immunodeficiency Syndrome↗