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Biomedical subjects

A Honig

Publications and source records attributed to A Honig.

At least 55 records · Page 3Linked to original sources
PubMed2000

Importance of decreased intracellular phosphate and magnesium concentrations and reduced ATPase activities in spontaneously hypertensive rats.

A decrease in total magnesium content is not a direct proof of a decreased magnesium ion concentration. It could reflect a phosphate alteration or an ATP metabolism disorder. Plasma phosphate levels are lower in spontaneously hypertensive rats (SHRs) than in Wistar-Kyoto (WKY) rats, and defects in membrane regulation or mitochondrial ATP synthase occur. Only sparse data exist concerning cellular magnesium and phosphate concentrations in hypertensive cells. In aortic smooth muscle cells from 10 SHRs of the Münster strain and 10 age-matched normotensive WKY rats, the intracellular phosphate and magnesium content was measured by electron probe X-ray microanalysis (Camscan CS 24 apparatus, Cambridge, U.K.). The Mg++ content was 0.90+/-0.15 g/kg dry weight in SHRs versus 1.15+/-0.10 g/kg dry weight in WKY rats (p<0.05). Vascular smooth muscle phosphate content was 23.6+/-0.79 g/kg dry weight in WKY rats versus 15.81+/-1.22 g/kg dryweight in SHRs (p<0.01). In seven animals, erythrocytic ATP content was 180.2+/-102 in SHRs vs. 432+/-72 micromol/L cells in WKY rats (p< 0.01). The Na+/K+-ATPase activity was significantly decreased in hypertensive animals as compared to controls (6.49+/-2.3 vs. 12.64+/-2.9 nmol inorganic phosphate/mg protein/min (p< 0.01)). Aortic smooth muscle cells from SHRs are characterized by markedly lowered cellular phosphate and magnesium concentrations and an altered ATP metabolism, possibly due to a membrane defect or a magnesium deficit in hypertensive cells.

Adenosine Triphosphate↗
PubMed1999

A controlled study of temporal lobe structure volumes and P300 responses in schizophrenic patients with persistent auditory hallucinations.

Recent studies of cerebral pathology in patients with schizophrenia have focused on symptomatological and electrophysiological correlates of reduced temporal lobe structure volumes. Volume deficits of the left superior temporal gyrus have been correlated with auditory hallucinations as well as to left-sided P300 amplitude reduction. However, caution is needed to interpret correlational data as evidence of a specific relationship. Therefore, a controlled study was undertaken on schizophrenic patients with and without auditory hallucinations. MRI-defined volumes of the left superior temporal gyrus and other temporal lobe structures were quantified from 3-mm coronal slices in 15 schizophrenic patients with chronic auditory hallucinations (hallucinators), 15 schizophrenic patients without auditory hallucinations (nonhallucinators) and 17 healthy controls. In all subjects a simple oddball paradigm was used to elicit P300 responses at temporal and centro-parietal electrode sites. No evidence was found for volume reductions of temporal lobe structures in the combined patient group compared with controls, or in the hallucinators compared with the nonhallucinators. The patients did show left P300 amplitude reduction compared with controls, particularly in the hallucinator group. Correlations between volumes of left temporal lobe structures and left P300 amplitudes were low and not significant. The results of the present study do not indicate that auditory hallucinations and associated abnormal electrophysiological activity are the consequence of atrophy of localized temporal lobe structures. However, replication in a larger sample of subjects is needed before firm conclusions can be drawn.

Adult↗
PubMed1999

Mood effects of 24-hour tryptophan depletion in healthy first-degree relatives of patients with affective disorders.

BACKGROUND: Acute tryptophan (TRP) depletion was evaluated in healthy volunteers with or without a family history of major affective disorder (FH+ versus FH-). METHODS: Twenty-seven subjects (16 FH+, 11 FH-) received 100 g of an amino acid mixture with and without TRP according to a placebo-controlled, double-blind cross-over design and a diet devoid of TRP for the next 24 hours. RESULTS: The ratio TRP/large neutral amino acids declined to 22% of baseline values after 6 hours, and increased during the night reaching 85% of baseline after 24 hours. Overall, after 6 hours, TRP depletion lead to a lowering of mood, but after 24 hours, these changes were no longer detected. Mood changes and gastrointestinal side effects were significantly more evident in FH+ subjects than in FH- subjects. CONCLUSIONS: Our data support the hypothesis that subjects with a positive family history for depression are predisposed to increased vulnerability to the adverse consequences of serotonergic imbalance.

Adolescent↗
PubMed1999

Lithium induced cognitive side-effects in bipolar disorder: a qualitative analysis and implications for daily practice.

Qualitative analysis of the literature on cognitive side-effects of lithium in patients with a bipolar disorder identified four of 17 studies that fulfilled criteria of adequate methodological quality. Analysis of these four studies showed that lithium had a negative effect on memory and speed of information processing, often without subjective complaints or awareness of mental slowness. The consequences of these findings for daily practice are discussed, in particular with respect to driving performance. When neurocognitive complaints or deficits are present, lithium plasma level, thyroid functions and degree of mood disturbance should be assessed. In cases where all these parameters are within normal limits and neurocognitive complaints still persist, dose reduction of lithium, thyroid hormone addition, prescription of a slow release preparation or replacement of lithium by another moodstabiliser should be considered. Guidelines are suggested with respect to further neuropsychological screening.

Antimanic Agents↗
PubMed1998

Cardiac side-effects of two selective serotonin reuptake inhibitors in middle-aged and elderly depressed patients.

Selective serotonin reuptake inhibitors (SSRIs) are the 'new' drugs of first choice for the treatment of depression in the older patient. Systematic studies on the effects of SSRIs on cardiac function are scarce, despite the high prevalence of cardiac disorders in the older depressed patient. This is a study which systematically assessed cardiac function by echocardiography in middle-aged and elderly depressed patients treated with SSRI. In a double-blind randomized trial, 20 patients were assigned to receive fluvoxamine 100 mg/day [DOSAGE ERROR CORRECTED] or fluoxetine 20 mg/day [DOSAGE ERROR CORRECTED] for 6 weeks. Cardiac function was assessed by left ventricle ejection fraction, aortic flow integral and early or passive/late or active mitral inflow, and electrocardiography. Neither SSRI significantly affected cardiac function. Compared with patients without a history of myocardial infarction and/or hypertension, patients with such a history showed a significant improvement in left ventricular ejection fraction. Despite our small study sample, these data indicate that both fluoxetine and fluvoxamine do not affect cardiac function adversely.

Aged↗
PubMed1998

Auditory hallucinations: a comparison between patients and nonpatients.

The form and the content of chronic auditory hallucinations were compared in three cohorts, namely patients with schizophrenia, patients with a dissociative disorder, and nonpatient voice-hearers. The form of the hallucinatory experiences was not significantly different between the three groups. The subjects in the nonpatient group, unlike those in the patient groups, perceived their voices as predominantly positive: they were not alarmed or upset by their voices and felt in control of the experience. In most patients, the onset of auditory hallucinations was preceded by either a traumatic event or an event that activated the memory of earlier trauma. The significance of this study is that it presents evidence that the form of the hallucinations experienced by both patient and nonpatient groups is similar, irrespective of diagnosis. Differences between groups were predominantly related to the content, emotional quality, and locus of control of the voices. In this study the disability incurred by hearing voices is associated with (the reactivation of) previous trauma and abuse.

Adult↗
PubMed1997

Psycho-education in bipolar disorder: effect on expressed emotion.

In a waiting-list controlled study on a multi-family psycho-educational intervention in bipolar disorder, key relatives in the treatment group showed a significant change from high to low levels of expressed emotion (EE) compared with the control group. In addition, patients with low-EE key relatives had a significantly lower number of hospital admissions compared with those living with high-EE key relatives. The multi-family groups were well received by the participants, and there were only a few drop-outs.

Adult↗
PubMed1997

[Depression following a first heart infarct; similarities with and differences from 'ordinary' depression].

OBJECTIVE: To determine frequency and clinical features of major depressive disorder according to DSM IV criteria in patients following a first myocardial infarction. DESIGN: Questionnaire. SETTING: Departments of Cardiology and Psychiatry, University Hospital Maastricht, the Netherlands. METHOD: Depression was assessed using the Zung 'Self-rating depression scale' (Zung-SDS) and the 'Symptom checklist' (SCL)-90 in 228 patients who filled the questionnaires out themselves (response: 60-70%), 1, 3, 6 en 12 months after their first heart attack. When the score on one or both lists was above threshold, the patient was invited for a clinical interview with a psychiatrist. RESULTS: One month post infarction 10% were diagnosed with a major depressive episode, a percentage which increased to 34% one year post infarction. The clinical features of the depression in these patients were the same as in a matched sample of depressed psychiatric inpatients without a cardiac history, except that hostility was significantly increased in the post-infarction patients. There was no mortality. CONCLUSION: Depressive disorder is a frequent comorbid disease after a first myocardial infarction.

Depression↗
PubMed1997

Erythrocyte carbonic anhydrase activity in smokers and in diabetic patients.

Carbonic anhydrase activity was measured in lyzed erythrocytes from smoking and non-smoking young men as well as from diabetic and healthy young women. Enzyme activity was determined by a changing-pH-assay, using a stirred reaction vessel and glass pH electrode. CAA was lower in smokers than in non-smokers. Furthermore, it was lower in diabetics than in nondiabetic controls. We conclude that cigarette smoking as well as diabetes mellitus may reduce erythrocyte carbonic anhydrase activity.

Adult↗
PubMed1996

Effects of acute hypoxia and hyperoxia on ventilation in spontaneously hypertensive and normotensive rat.

The aim of this study was to investigate whether there are differences between particular characteristics of the ventilatory responses to acute hypoxia and hyperoxia in primary hypertensive and normotensive states which might indicate significant differences in arterial chemoreceptor reflex function. Pneumotachographic monitoring of ventilation was carried out in anesthetized, spontaneously breathing, normotensive randomly bred Wistar rats (NWR), Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Under air breathing conditions, minute ventilation in SHR (50 +/- 2 ml/min per 100 g) was not significantly different from that of WKY (54 +/- 3 ml/min per 100 g) but NWR had a significantly lower minute ventilation (39 +/- 1 ml/min per 100 g) than both SHR and WKY. Our data indicate that there is no elevation of the ventilatory drive under air breathing conditions which can be unequivocally associated with primary hypertension in adult animals. During acute hypoxia, minute ventilation increased by a similar magnitude in SHR and NWR (by 97 and 77%, respectively, above baseline values), whereas in WKY the increase was only 58%. When exposed to acute hyperoxia, minute ventilation was inhibited by a similar degree in all animals investigated. We conclude that there is no characteristic pattern of peripheral chemoreceptor-mediated ventilatory responses in close association with primary hypertension.

Animals↗
PubMed1996

Selective serotonin reuptake inhibitors (SSRIs) in the treatment of elderly depressed patients: a qualitative analysis of the literature on their efficacy and side-effects.

A qualitative analysis of studies on the efficacy and side-effects of selective serotonin reuptake inhibitors (SSRIs) for the treatment of elderly people with depression is presented. Only placebo-controlled or comparison studies of SSRI versus other antidepressants were included. The description and methodological quality of the analysed studies were important criteria in the outcome of the analysis. Quality was assessed by means of a blinded review approach. After excluding duplicate publications, 16 studies were analysed, of which six turned out to be of good quality. The results indicated that at the end of the treatment periods (4-8 weeks) all antidepressants were equally effective. Side-effects occurred less frequently with SSRIs than with tricyclics (TCAs), and different side-effect profiles were found. Significantly fewer SSRI-treated patients than TCA-treated patients dropped out both overall and due to side-effects.

1-Naphthylamine↗
PubMed1996

Cardiorespiratory and renal responses to arterial chemoreceptor stimulation by hypoxia or almitrine in men.

1. The cardiorespiratory and renal responses to 3 h of normobaric whole-body hypoxic hypoxia (FiO2 = 0.12) as well as to arterial chemoreceptor stimulation by the oral administration of 100 mg almitrine bismesylate during normoxia were measured in 12 normotensive young men undergoing water diuresis. A third series of responses obtained under comparable conditions in the same subjects served as time controls. 2. No significant changes could be detected over time in the parameters measured in control experiments. The subjects reacted to both whole-body hypoxic hypoxia and to pharmacological chemoreceptor stimulation with significant increases in heart rate, tidal volume, minute ventilation and filtration-fraction. Overall renal vascular resistance rose significantly in hypoxia; increases in renal vascular resistance in almitrine experiments were not significant. 3. Renal fractional lithium excretion decreased significantly in response to whole-body hypoxic hypoxia and increased slightly in response to almitrine. Fractional urine and sodium excretion showed negligible changes. 4. The data indicate that, in humans, both almitrine and whole-body hypoxic hypoxia affect not only alveolar ventilation but also renal haemodynamics. 5. The renal electrolyte excretion pattern suggests that under certain circumstances (e.g. dilated renal vascular bed) acute, but well-tolerated, whole-body hypoxic hypoxia can simultaneously stimulate renal proximal tubular sodium reabsorption and inhibit distal tubular sodium reabsorption. The renal tubular responses also indicate that almitrine may influence renal tubular lithium reabsorption by, thus far, unknown mechanisms.

Adult↗
PubMed1996

Effect of arterial chemoreceptor stimulation with almitrine bismesylate on plasma renin activity, aldosterone, ACTH and cortisol in anaesthetized, artificially ventilated cats.

1. Changes in plasma renin activity (PRA) and in the plasma concentration of aldosterone, adrenocorticotrophic hormone (ACTH) and cortisol in response to an intravenous infusion of the chemoreceptor stimulant almitrine bismesylate (0.2 mg/kg) were studied in two groups of anaesthetized, paralysed and constantly ventilated cats. In one group, the peripheral arterial chemoreceptors remained innervated, whereas in the other they were denervated by bilateral cervical vagotomy and section of the carotid sinus nerves. 2. Animals with innervated chemoreceptors (n = 16) reacted to almitrine bismesylate with a significant (P <0.05) increase in both ACTH and cortisol. These responses were not present in cats in which the peripheral arterial chemoreceptors had been surgically denervated (n = 16). 3. Plasma renin activity and plasma aldosterone increased with time during experiments on both the chemoreceptor-intact and chemoreceptor-denervated cats. Almitrine did not affect the time course of the rise in PRA and plasma aldosterone in either group of animals. 4. These data indicate that, under the conditions of our experiments, almitrine induced arterial chemoreceptor reflex mechanisms stimulate ACTH and cortisol release, but has no chemoreceptor-dependent influence on PRA or plasma aldosterone.

Adrenocorticotropic Hormone↗
PubMed1996

Cardiorespiratory and renal responses to arterial chemoreceptor stimulation in early hypertension.

The peripheral arterial chemoreceptors (PAC) modify not only cardiorespiratory but also renal hemodynamic and excretory function. There is evidence that in hypertensive animals and humans the reflectoric actions of the PAC on ventilation and circulation differ from those of normotensive subjects. However, the influence of these receptors on kidney function of hypertensive subjects is poorly understood. Cardiorespiratory and renal responses to pharmacological stimulation of PAC by almitrine bismesylate during normoxia were measured in 16 normotensive (NT) and 13 age-matched borderline-hypertensive young men (BHT) undergoing water diuresis. Placebo experiments served as time controls in each subject. NT reacted to almitrine with significant rises in heart rate, minute ventilation, and filtration fraction. Renal vascular resistance tended to increase slightly. In BHT the drug caused a significant rise in heart rate and minute ventilation too, however, this reaction had a longer latency when compared to NT. In contrast to NT, filtration fraction, and renal vascular resistance decreased. Renal fractional sodium and lithium excretion did not show any clear response to almitrine in NT, but decreased in BHT. The results suggest that the weaker ventilatory response in BHT vs. NT might indicate a lower reactivity of their PAC to almitrine. The different reactions of the renal vascular bed to pharmacological chemoreceptor excitation in mild hypertensives might result from a different reactivity of the renal arterioles, whereas the enhanced proximal tubular sodium reabsorption could be due to an exaggerated increase in efferent renal nerve activity.

Adult↗
PubMed1995

Psychoeducation and expressed emotion in bipolar disorder: preliminary findings.

A multifamily psychoeducational intervention was carried out in patients with bipolar disorder. The study explored (1) the effects of the intervention on the level of expressed emotion (EE) of key relatives; (2) the validity of EE defined by a 5-min speech sample as a predictor of relapse; and (3) the evaluations of the intervention program by patients and key relatives. Four key relatives in the treatment group, compared with none in a waiting list control group, changed from high to low EE levels. The change was clinically but not statistically significant, perhaps because of the small sample size. Patients whose key relatives had low EE levels had a significantly lower number of relapses and hospital admissions compared with those whose key relatives had high EE levels. The psychoeducational program was well received by all participants, and there were no dropouts.

Bipolar Disorder↗