Cardiac failure in beef cattle fed dried poultry litter.
Explore the source record for details and available documents.
Animal Feed↗
Biomedical subjects
M Davidson
Publications and source records attributed to M Davidson.
Changes in plasma homovanillic acid concentrations in schizophrenic patients following neuroleptic discontinuation.
Changes in plasma levels of the dopamine metabolite homovanillic acid have been reported to correlate with changes in the severity of schizophrenic symptoms during neuroleptic administration and after neuroleptic discontinuation. This study examined the effects of discontinuation of neuroleptic treatment on plasma homovanillic acid levels in 23 patients with chronic schizophrenia. It was hypothesized that clinical decompensation would be associated with increased plasma homovanillic acid levels. Plasma homovanillic acid was measured during administration of neuroleptic medication and during a subsequent 6-week drug-free period. Nine patients decompensated during the drug-free period and 14 patients did not. Following drug discontinuation, plasma homovanillic acid concentrations were higher in schizophrenic patients who decompensated than in those who did not. Furthermore, peak plasma homovanillic acid elevation after discontinuation of neuroleptic medication was significantly correlated with peak Brief Psychiatric Rating Scale increase. The data suggest that, in some schizophrenic patients, symptomatic decompensation after discontinuation of neuroleptic treatment is associated with increases in dopamine turnover.
Adult↗
Effects of neuroleptic treatment on symptoms of schizophrenia and plasma homovanillic acid concentrations.
Measurement of plasma concentrations of the dopamine metabolite, homovanillic acid, is an indirect tool to assess changes in dopamine turnover in schizophrenic patients. Plasma homovanillic acid concentrations have been reported to decrease during neuroleptic treatment, with the decrement correlating with symptomatic improvement in symptoms of schizophrenia. The present study tested the hypothesis that neuroleptic drugs decrease plasma homovanillic acid concentrations in those schizophrenic patients who improve with administration of neuroleptic drugs but not in patients who fail to display a treatment response. Twenty schizophrenic men who remained drug free for at least 2 weeks were treated with 20 mg/d of haloperidol for 5 weeks. Symptoms and plasma homovanillic acid concentrations were assessed on the last drug-free day and weekly for 5 weeks. Mean plasma homovanillic acid concentrations decreased in the group of patients who responded to neuroleptic treatment and did not change in the group of patients who did not improve. These findings suggest that there may be a qualitative distinction between responders and nonresponders to dopamine antagonists.
Administration, Oral↗
Effects of indomethacin on plasma homovanillic acid concentration in normal subjects: a study of prostaglandin-dopamine interactions.
In laboratory animals, prostaglandins have been shown to act as endogenous neuromodulators of central dopamine (DA) activity. To examine the interaction between prostaglandins and DA in man, the effect of a prostaglandin synthesis inhibitor, indomethacin, was studied on plasma concentrations of the DA metabolite, homovanillic acid (pHVA). Indomethacin (150 mg PO) as compared to placebo significantly elevated mean pHVA concentrations in eight normal subjects. Results of this study support the hypothesis that, as in animals, inhibition of prostaglandin synthesis increases central DA turnover in man.
Adult↗
Nongenital pelvic leiomyosarcoma metastatic to the heart.
A patient who had a 5-year history of a low-grade nongenital pelvic leiomyosarcoma was evaluated for worsening dyspnea, hypertension, and jugular venous distension. An echocardiogram revealed a large right atrial mass. At surgical exploration, metastatic leiomyosarcoma was found within the inferior vena cava extending from below the renal veins up into the right atrium. Using cardiopulmonary bypass with profound hypothermia and circulatory arrest, the inferior vena cava was opened below the renal veins, and the tumor was transected. That portion of the tumor above this transection was then extracted through a right atriotomy. Resection of the pelvic tumor was not thought to be feasible. The patient remains asymptomatic with stable pelvic tumor 1 year after the procedure.
Female↗
Brief neuroleptic discontinuation and clinical symptoms in Kraepelinian and non-Kraepelinian chronic schizophrenic patients.
Neuroleptic medication was abruptly discontinued in 24 male chronic schizophrenic patients who were subdivided on the basis of their history of illness into Kraepelinian (n = 8) and non-Kraepelinian (n = 16) subgroups. These patients were kept drug free for 6 weeks and then returned to treatment with haloperidol, 20 mg/day. Half of the non-Kraepelinian patients developed exacerbations of their symptoms, which quickly resolved when they were returned to medication, while none of the Kraepelinian patients showed a worsening of symptomatology. On-medication clinical severity failed to predict risk for exacerbation, with severity of exacerbation predicting the amount of improvement when returned to medication. The Kraepelinian patients were found to be much less variable than the non-Kraepelinian patients in their symptoms during both medication manipulations, suggesting that medication truly has a negligible effect on them.
Antipsychotic Agents↗
Continuous performance tests in schizophrenic patients: stimulus and medication effects on performance.
Medicated (n = 17) and unmedicated (n = 17) schizophrenic patients were compared to a normal control group (n = 19) on their performance on auditory and visual versions of the Continuous Performance Test (CPT). Within each stimulus modality, performance was examined on lexical and nonlexical target stimuli. Neuromotor competence was assessed on the basis of motor speed and proficiency. Normal subjects made fewer errors of all types than schizophrenic patients. Unmedicated patients made significantly more errors on nonlexical stimuli than medicated patients, with medication status found not to be associated with stimulus modality effects. Motor proficiency was associated with CPT performance in the medicated patients, but not the unmedicated ones, although this difference in correlations did not account for the group differences between these patients. The authors discuss the implications of these data for the type of cognitive and attentional functions that are affected by medication in schizophrenia.
Adult↗
Effect of concurrent distraction on communication failures in schizophrenic patients. II. Medication status correlations.
In order to examine the effects of irrelevant distracting information on speech disorder, medicated (n = 13) and unmedicated (n = 18) schizophrenics were compared to a mixed affective sample (n = 15) on the frequencies of linguistic measures of verbal communication disorder. Patients conversed with an interviewer during the presence and absence of irrelevant information inserted into their conversation. Affective patients manifested no distraction-related increase in communication disorder. Schizophrenics on medication manifested a small, but nonsignificant, increase in communication disorders during the concurrent distraction condition. Unmedicated schizophrenics manifested a substantial increase in their communication disorders during distraction. These data suggest that medication reduces the extent to which speech processes in schizophrenia are vulnerable to overload-related deterioration and provide confirmation of the hypothesis that some component of positive thought disorder in schizophrenia is due to medication-responsive attention deficits.
Adult↗
Time course and clinical predictors of treatment response in schizophrenia.
The severity of schizophrenic symptoms was examined in 50 male chronic patients while neuroleptic free for at least 3 weeks and during 6 weeks of treatment with haloperidol. The results suggested that 50% of the improvement associated with haloperidol administration occurred by the end of the first treatment week and that early improvement, at both 1 and 4 weeks of treatment, was predictable from drug-free symptom severity. There was a negative correlation between week 1 improvement and improvement during the next 3 weeks of treatment, suggesting that medication response is not linear. Finally, dose increases after 4 weeks of treatment with 20 mg of haloperidol did not lead to any clinical improvement. These results are discussed in terms of their implications for selecting chronic schizophrenic patients who will and will not benefit from medication treatment.
Adult↗
The liver/erythrocyte pyruvate kinase gene complex [Pk-1] in the mouse: regulatory gene mutations.
Nine enzyme activity variants and one charge variant of liver/erythrocyte pyruvate kinase have been found amongst laboratory and wild mice. Four of the enzyme activity variants were previously reported to be caused by allelic differences in the structural gene, Pk-1s. Analysis of two putative regulatory gene mutations is now reported, both of which map at, or close to, the structural gene on chromosome 3. One of these mutations, in the inbred strain SWR, is tissue specific, affecting enzyme concentration in the liver but not the erythrocyte the other, which arose in a mutation experiment, doubles the enzyme concentration in both tissues. The organization and the nomenclature in the [Pk-1] gene complex are discussed and are compared with the organization of other comprehensively analysed gene complexes in the mouse.
Animals↗
Cholinergic strategies in the treatment of Alzheimer's disease.
Since the identification of the cholinergic deficit, strategies aimed at enhancing cholinergic neurotransmission have dominated the field of pharmacology in Alzheimer's disease (AD). These strategies include increasing acetylcholine precursor availability, delaying synaptic degradation and stimulating muscarinic receptors. Although most clinical trials report mild symptomatic improvements in some patients, support for large-scale clinical use of cholinomimetics in AD is not yet available. This article presents the most representative clinical trials, discusses the limitations of the cholinergic strategies and suggests future directions in the treatment of AD.
Acetylcholine↗
Neuron-like cells in culture of tuberous sclerosis tissue.
Explore the source record for details and available documents.
Antibodies, Monoclonal↗
Affective and impulsive personality disorder traits in the relatives of patients with borderline personality disorder.
OBJECTIVE: This study tested the hypothesis that the risk for affective and impulsive personality disorder traits commonly found in patients with borderline personality disorder would be greater in the first-degree relatives of probands with borderline personality disorder than in two comparison groups. METHOD: Blind family history interviews were conducted with family informants to assess the extent to which first-degree relatives of 29 probands with borderline personality disorder, 22 probands with other personality disorders who met three or fewer of the criteria for borderline personality disorder, and 43 probands with schizophrenia fulfilled operationalized criteria for the two kinds of personality disorder traits and for other diagnostic categories. The crude proportions of adult relatives with each diagnosis, as well as the age-adjusted morbid risks, were assessed in the three groups of relatives. RESULTS: The risks for affective and impulsive personality disorder traits were independently greater in the 129 relatives of the borderline probands than in the 105 relatives of the probands with other personality disorders and the 218 relatives of the schizophrenic probands. There was no similarly greater risk for any other psychiatric disorder assessed, including major affective disorder. In addition, the relatives of borderline probands with current or past major depressive disorder showed a greater risk for major affective disorders than the relatives of never-depressed probands with other personality disorders but not the relatives of never-depressed borderline probands. CONCLUSIONS: These results suggest familial transmission of the hallmark borderline-related personality characteristics and raise the possibility that these familial traits may be partially independent.
Adult↗
Dopamine in schizophrenia: a review and reconceptualization.
OBJECTIVE: The initial hypothesis that schizophrenia is a manifestation of hyperdopaminergia has recently been faulted. However, several new findings suggest that abnormal, although not necessarily excessive, dopamine activity is an important factor in schizophrenia. The authors discuss these findings and their implications. METHOD: All published studies regarding dopamine and schizophrenia and all studies on the role of dopamine in cognition were reviewed. Attention has focused on post-mortem studies, positron emission tomography, neuroleptic drug actions, plasma levels of the dopamine metabolite homovanillic acid (HVA), and cerebral blood flow. RESULTS: Evidence, particularly from intracellular recording studies in animals and plasma HVA measurements, suggests that neuroleptics act by reducing dopamine activity in mesolimbic dopamine neurons. Post-mortem studies have shown high dopamine and HVA concentrations in various subcortical brain regions and greater than normal dopamine receptor densities in the brains of schizophrenic patients. On the other hand, the negative/deficit symptom complex of schizophrenia may be associated with low dopamine activity in the prefrontal cortex. Recent animal and human studies suggest that prefrontal dopamine neurons inhibit subcortical dopamine activity. The authors hypothesize that schizophrenia is characterized by abnormally low prefrontal dopamine activity (causing deficit symptoms) leading to excessive dopamine activity in mesolimbic dopamine neurons (causing positive symptoms). CONCLUSIONS: The possible co-occurrence of high and low dopamine activity in schizophrenia has implications for the conceptualization of dopamine's role in schizophrenia. It would explain the concurrent presence of negative and positive symptoms. This hypothesis is testable and has important implications for treatment of schizophrenia and schizophrenia spectrum disorders.
Animals↗
Plasma homovanillic acid in schizotypal personality disorder.
Schizotypal patients were found to have a significantly higher mean plasma HVA concentration than normal comparison subjects. Furthermore, plasma HVA concentration positively correlated with "psychotic-like" schizotypal symptoms. These results implicate dopaminergic mechanisms modulating the psychotic-like symptoms of schizotypal personality disorder.
Dopamine↗
Safety of percutaneous lung needle aspiration.
Explore the source record for details and available documents.
Biopsy, Needle↗
Diagnostic and pharmacological approaches in Alzheimer's disease.
Alzheimer's disease is a chronic progressive disease affecting higher intellectual functioning. The clinical diagnosis is made when the onset of illness is insidious, the course slowly progressive and all the treatable causes of dementia have been ruled out. The use of more stringent criteria has improved clinical diagnosis, but at best only 80% of patients are accurately diagnosed. Ultimately the diagnosis depends upon pathological confirmation. The neuritic plaques and neurofibrillary tangles described by Alzheimer, although not pathognomonic for the disease, continue to be the basis for pathological diagnosis. The aetiology and pathophysiology of Alzheimer's disease are presently unknown. Epidemiological studies have suggested a genetic basis for the disorder, and many biochemical studies have linked it to degeneration of central cholinergic neurons, and possibly to abnormalities of other neurotransmitter systems. A marker which would permit accurate diagnosis early in the course of disease would be of major importance to researchers and clinicians alike. No marker has been found to date, although recent research results are promising. Various pharmacological strategies have been employed in the treatment of Alzheimer's disease. More recently attempts have focused on enhancing central cholinergic transmission. Despite the well-founded rationale for these studies, results have been modest.
Alzheimer Disease↗
The use of benzodiazepines in the management of behavioral symptoms in demented patients.
Hard data on the efficacy of benzodiazepines in the treatment of behavioral disturbances in Alzheimer's disease are not available. Short-acting benzodiazepines, such as oxazepam, appear safer than long-acting benzodiazepines and more efficient than placebo in the short-term (4-8 weeks) treatment of behavioral disturbances in geriatric, psychogeriatric, and demented patients. It is unknown whether oxazepam is superior to neuroleptic drugs or other commonly prescribed sedatives in this context. To some extent these findings may apply to patients with Alzheimer's disease as well, but there are several arguments against an uncritical extrapolation of conclusions drawn from other geriatric populations to patients with Alzheimer's disease. When, despite the lack of well-founded knowledge in this field, such a treatment modality is chosen, short-acting benzodiazepines should be preferred over long-acting agents. Drug interactions and pharmacokinetic aspects of the specific agent in the individual patient should always be considered carefully. Future studies on the treatment of behavioral disturbances in Alzheimer's disease need to clarify which specific behavioral symptoms should be treated pharmacologically, which therapeutic agents have the most advantageous risk-benefit ratio in this context, and what is the optimal treatment duration.
Aged↗