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Biomedical subjects

M Davidson

Publications and source records attributed to M Davidson.

At least 109 records · Page 6Linked to original sources
PubMed1997

Identification of the DRB1*1313 allele in a sibling pair.

Sequence-specific oligonucleotide probe hybridization (PCR/SSOP), which is now routinely used in HLA laboratories to type for alleles of the class II loci, can also detect the presence of previously unknown alleles. In the course of clinical typing for DRB1, we identified two samples with probe hybridization patterns appropriate for DRB1*1313, a previously submitted sequence that had been withdrawn. Direct sequencing showed that the two individuals carried an allele with an exon 2 sequence identical to that previously submitted for DRB1*1313.

Alleles↗
PubMed1997

Age-related differences in formal thought disorder in chronically hospitalized schizophrenic patients: a cross-sectional study across nine decades.

OBJECTIVE: This study used a cross-sectional design to examine the frequency of occurrence and severity of 10 different signs of thought disorder in schizophrenic patients across the lifespan. METHOD: Schizophrenic patients, who ranged in age from 19 to 96 years (N = 392), were examined with the Scale for Assessment of Thought, Language, and Communication. The cognitive functioning of the geriatric patients (patients over the age of 64, N = 120) was also assessed. RESULTS: Poverty of speech was more common and more severe in geriatric patients, while four different signs of thought disorder that reflect disconnected speech were less common and less severe in geriatric patients. Analysis of covariance found that the lower severity of disconnection thought disorders in the older patients was not attributable to differences in the amount of speech produced. CONCLUSIONS: Aspects of disconnected speech were less severe in older patients, while the severity and frequency of poverty of speech were greater. These findings suggest that the two previously identified separate dimensions of communication disorder in schizophrenia vary differently with age and possibly in their cognitive and biological underpinnings.

Adult↗
PubMed1997

Verbal fluency deficits in geriatric and nongeriatric chronic schizophrenic patients.

This study examined age-related differences and correlates of deficits on phonological and category fluency tasks performed by schizophrenic patients. Equal numbers (n = 41) of geriatric (age > 64) and nongeriatric chronically hospitalized schizophrenic patients were examined with tests of phonological and category fluency, verbal learning and delayed recall, confrontation naming, and reading, as well as overall estimates of cognitive impairment. Both types of fluency tests were performed very poorly by both groups. Age-related differences were found to be statistically significant. In both groups, category fluency impairments were correlated with deficits in naming, while phonological fluency deficits were best predicted by memory impairments. These data suggest that category fluency impairments are part of a general profile of impaired semantic functioning, whereas phonological fluency deficits may be induced by alterations in information processing capacity.

Aged↗
PubMed1997

Symptom severity and cognitive impairment in chronically hospitalised geriatric patients with affective disorders.

BACKGROUND: Affective disorders typically have a better outcome than schizophrenia, although recent evidence suggests that some patients with affective disorder have a relatively poor outcome, with cognitive impairments and persistent symptomatology. METHOD: Fifty chronically hospitalised geriatric patients with mood disorders (major depression or bipolar disorder) were compared on the clinical symptoms and aspects of cognitive impairment with 308 geriatric schizophrenic patients who were hospitalised at the same institution. The two samples did not differ in current age or in premorbid education level, but the affective patients had a later age of onset and more females in the sample. RESULTS: There were no overall differences in cognitive functioning between the groups, although the clinical symptom profiles resembled those seen in better outcome patients. CONCLUSIONS: Cognitive impairment is present in poor-outcome patients with affective disorders as well as schizophrenia, suggesting that cognitive impairments predict poor outcome across psychiatric disorders and not just in schizophrenia.

Aged↗
PubMed1997

Oral rabies vaccination of red foxes and golden jackals in Israel: preliminary bait evaluation.

Field trials were conducted in late April to early May of 1995 and 1996 in central Israel to assess the potential for controlling rabies in red foxes (Vulpes vulpes) and golden jackals (Canis aureus) by using vaccine-laden baits. Of the bait types which were field tested, polymer fish meal baits were selected as the most suitable for both species. Fish meal baits containing tetracycline hydrochloride, an oral biomarker, were distributed by four-wheel-drive vehicle at a density of approximately 30 baits/km2 in two test areas of 35 km2. Of the animals which were trapped and euthanized seven to ten days after treatment, 65% of foxes and 56% of jackals gave positive results when tested for the biomarker. These results indicate the potential effectiveness of oral rabies vaccination of these species in Israel and possibly elsewhere in the Middle East, where rabies is a problem in wild canids.

Administration, Oral↗
PubMed1997

Cost effectiveness of treatment to National Cholesterol Education Panel (NCEP) targets with HMG-CoA reductase inhibitors. Trial design.

HMG-CoA reductase inhibitors effectively reduce cholesterol levels, and this is associated with a lower rate of cardiovascular events. Some HMG-CoA reductase inhibitors are more effective than others in reducing low density lipoprotein (LDL) cholesterol, and such drugs should help patients achieve LDL cholesterol targets prescribed by the National Cholesterol Education Panel (NCEP). This paper describes the design of a trial comparing the clinical efficacy and cost effectiveness of four HMG-CoA reductase inhibitors in reducing LDL cholesterol to specified targets. This trial is being conducted in 30 physicians' practices in the USA. Its primary aim is to assess the resource use required to achieve and maintain NCEP targets by all patients randomised and followed up for one year.

Anticholesteremic Agents↗
PubMed1997

Comparison of combination therapy with paclitaxel and cisplatin versus cyclophosphamide and cisplatin in patients with suboptimal stage III and stage IV ovarian cancer: a Gynecologic Oncology Group study.

This prospective study compared the combination of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) and cisplatin with the standard therapy of cyclophosphamide/cisplatin in women with suboptimal stage III and stage IV ovarian cancer. Of the initial 410 women who presented with advanced disease and greater than 1 cm residual masses after initial surgery, 386 met all eligibility criteria and were randomly assigned to receive a regimen of cisplatin 75 mg/m2 and cyclophosphamide 750 mg/m2 or cisplatin 75 mg/m2 and paclitaxel 135 mg/m2 delivered over 24 hours. Dosage reductions were permitted in the event of significant toxicity. Among 216 patients with measurable disease, responses were reported in 73% of those receiving cisplatin/paclitaxel and in 60% of those receiving cisplatin/cyclophosphamide. Median progression-free survival was significantly longer (P < .001) in the group treated with cisplatin/paclitaxel, compared with those receiving cisplatin/cyclophosphamide (17.9 v 12.9 months, respectively).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Cognitive impairment and negative symptoms in geriatric chronic schizophrenic patients: a follow-up study.

Cognitive impairment is increasingly recognized as an important aspect of schizophrenia. Since cognitive impairment has many features in common with the negative symptoms of the illness, it is possible that some of the characteristics attributed to negative symptoms are due to an association with cognitive impairments. In order to test this hypothesis, 174 chronically hospitalized geriatric schizophrenic patients were examined twice at a 1-year follow-up with ratings of the severity of their symptoms (using the Positive and Negative Syndrome Scale: PANSS) and assessments of cognitive functions with the Mini-Mental State Examination and a brief neuropsychological battery aimed at the typical impairments seen in dementia. Positive symptoms were unassociated with any of the cognitive variables, while negative symptom severity was correlated with each of the cognitive measures. In the cross-temporal analyses, cognitive impairments were more stable over time than negative symptom scores, but cognitive impairment did not predict the severity of any negative symptom over time. At each assessment, however, cognitive impairment was strongly correlated with each of the seven negative symptoms studied. These data indicate that cognitive impairments and negative symptoms are related, but discriminable, features in schizophrenia and that the considerable overlap between some negative symptoms and estimates of cognitive function may suggest a rethinking of the definition of some of these symptoms.

Aged↗
PubMed1996

Empirical evaluation of the factorial structure of clinical symptoms in schizophrenia: effects of typical neuroleptics on the brief psychiatric rating scale.

There has been little investigation of the effect of neuroleptic medication on the structure of symptoms in schizophrenia. In this study, 135 male schizophrenic patients were rated with the Brief Psychiatric Rating Scale (BPRS) after 4 weeks of treatment with typical neuroleptic medication and after 2 weeks free of neuroleptics, with the order of assessment varying across patients. Confirmatory factor analyses (CFA) found that there were no differences in symptom structure across medication status and no differences in the structure of symptoms in treatment responders and nonresponders. The typical 5-factor BPRS model fit the data poorly and the fit improved considerably through deletion of items measuring symptoms not associated with schizophrenia, suggesting that some of the symptoms that contribute to a total BPRS score may be adding primarily error variance. Although the sample size in this study is limited, the results suggest that using total BPRS scores to measure severity of schizophrenic symptoms should be reconsidered.

Adult↗
PubMed1996

Lack of effect of laboratory-provoked anxiety on plasma homovanillic acid concentration in normal subjects.

The present study was undertaken to investigate if acute anxiety can affect plasma concentrations of homovanillic acid (pHVA). Since elevated pHVA levels have been associated with severity of schizophrenic symptoms, the results of this study will help determine if the pHVA elevations are directly related to psychosis or if anxiety is also a contributory factor. Anxiety was provoked in 10 young normal subjects by a combined paradigm of mental arithmetic task and threat of electrical shock. A significant increase in self-ratings of anxiety, blood pressure, and plasma levels of norepinephrine, 3-methoxy-4-hydroxyphenylethyleneglycol and growth hormone indicated that the paradigm used was effective in provoking anxiety; however, anxiety did not affect pHVA concentrations. The results may support the notion that increased pHVA levels in severely ill schizophrenic patients are related to the schizophrenic pathophysiology rather than to anxiety.

Adult↗
PubMed1996

Cost-effectiveness of pravastatin in secondary prevention of coronary artery disease.

This study analyzed the cost-effectiveness of pravastatin in secondary prevention of coronary artery disease (CAD). The projected risk model in 445 male patients with established CAD and moderately elevated serum low-density lipoprotein cholesterol used results data from 2 placebo-controlled plaque regression trials: Pravastatin Limitation of Atherosclerosis in the Coronary Arteries and Pravastatin, Lipids, and Atherosclerosis in the Carotids. Framingham Heart Study data were used to project the risk of mortality 10 years after myocardial infarction (MI) for incremental male patients in the placebo group who had MI. A Markov process was used to estimate life-years saved, and decision analysis was used to estimate cost. Depending on the patient-risk profile, the midrange estimated cost per life-year saved with pravastatin in secondary prevention of CAD varied from $7,124 to $12,665, which is favorable compared with other widely accepted medical interventions.

Anticholesteremic Agents↗
PubMed1996

Isolation of a mouse theta glutathione S-transferase active with methylene chloride.

A glutathione S-transferase metabolizing methylene chloride has been isolated from mouse liver using a variety of chromatographic methods. N-terminal and internal amino acid sequences show that the enzyme, designated GST T1-1*, is closely related to the rat Theta-class GST 5-5. The mouse enzyme, molecular mass 25000 Da, has been isolated to homogeneity in active form with an approximate yield of 2% of the cytosolic activity towards methylene chloride. GST T1-1* has a specific activity of about 5.5 micromol/min per mg of protein whereas the rat GST 5-5 is reported to have a specific activity of about 11 micromol/min per mg of protein [Meyer, Coles, Pemble, Gilmore, Fraser and Ketterer (1991) Biochem. J. 274, 409-414], demonstrating that both the rat and mouse enzymes have similar activity with this substrate. Limited evidence was obtained for a second enzyme, with a similar molecular mass (25400 Da), which had an N-terminal sequence identical to that of rat GST 12-12. This protein, which was sequenced from a band on a gel, was extremely labile and could not be isolated to homogeneity. The partially purified enzyme was not active with methylene chloride.

Amino Acid Sequence↗
PubMed1996

Age disorientation in chronically hospitalized patients with mood disorders.

Age disorientation was studied in 45 geriatric patients with chronic mood disorders. In a yearly assessment of cognitive functions, subjects were questioned about their age, year of birth, and the current year. Patients who misstated their age by > or = 5 years were considered age disoriented. Among the 45 patients, age-disorientation data were available for 32 patients, with the remainder either stating that they did not know their age or providing age-delusional responses. Six of the 32 patients were characterized as age disoriented at baseline and again at 12- to 18-month follow-up assessment. Age-disoriented patients performed worse overall on the Mini-Mental State Examination compared with patients who did not show age disorientation. Future studies of brain function and structure should include poor-outcome patients with mood disorders as well as patients with schizophrenia in attempts to identify the possible neurological dysfunctions that may underlie the phenomenon of age disorientation.

Adult↗
PubMed1996

Neuropeptide deficits in schizophrenia vs. Alzheimer's disease cerebral cortex.

Neuropeptide concentrations were determined in the postmortem cerebral cortex from 19 cognitive-impaired schizophrenics, 4 normal elderly subjects, 4 multi-infarct dementia (MID) cases, and 13 Alzheimer's disease (AD) patients. Only AD patients met criteria for AD. The normal elderly and MID cases were combined into one control group. Somatostatin concentrations were reduced in both schizophrenia and AD. Neuropeptide Y concentrations were reduced only in schizophrenia, and corticotropin-releasing hormone concentrations were primarily reduced in AD. Concentrations of vasoactive intestinal polypeptide and cholecystokinin also were reduced in schizophrenia, although not as profoundly as somatostatin or neuropeptide Y. In AD, cholecystokinin and vasoactive intestinal peptide were unchanged. Neuropeptide deficits in schizophrenics were more pronounced in the temporal and frontal lobes than in the occipital lobe. The mechanisms underlying these deficits in schizophrenia and AD are likely distinct. In schizophrenia, a common neural element, perhaps the cerebral cortical gaba-aminobutyric acid (GABA)-containing neuron, may underlie these deficits.

Aged↗
PubMed1996

Symptom stability in geriatric chronic schizophrenic inpatients: a one-year follow-up study.

The results of previous studies of symptom stability in schizophrenia suggest that negative symptoms manifest traitlike characteristics while positive symptoms fluctuate over time. Various prospective studies of chronic schizophrenic patients have found consistent results, regardless of the follow-up period, yet there is little research addressing symptomatology in geriatric schizophrenic patients. Since these patients have a very poor outcome and more severe negative symptoms, their symptoms might differ from younger patients. This study examined the course of symptomatology in 178 geriatric schizophrenic inpatients who were assessed twice at a 1-year interval with the Positive and Negative Syndrome Scale (PANSS). Intraclass correlations revealed that the distribution of negative symptoms was considerably more stable than that of positive symptoms over the interval, and subtypes based on negative symptoms were the only ones that manifested consistent stability over time. There was also a significant increase in negative symptom severity for the sample, with a slight decrease in positive symptom severity. Thus, even in chronic inpatients, with a very extended illness, positive symptom severity is not particularly stable within patients. These data indicate that the characteristics of negative and positive schizophrenic symptoms are similar in younger and geriatric schizophrenic patients, suggesting a continuity of the illness process. Tentative evidence for increasing severity of negative symptoms over a brief follow-up period suggests the possibility of a steady worsening of clinical state in very elderly patients who remained hospitalized.

Age Factors↗