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Biomedical subjects

H U Fisch

Publications and source records attributed to H U Fisch.

At least 37 records · Page 2Linked to original sources
PubMed1992

Paradoxical effects of mild hypoxia and moderate altitude on human visual perception.

1. Prolonged (> 10 h) exposure to hypoxia and high altitude (> 5000 m) invariably have detrimental effects on cognitive performance. Paradoxically, mild improvements in cognitive function in patients with chronic obstructive pulmonary disease after cessation of oxygen therapy have been reported. 2. We studied in each of 10 healthy subjects the effect of an acute altitude challenge [rapid helicopter transport to the Jungfraujoch (3450 m), experiment 1] and of an acute exposure to mild hypoxia (fractional inspiratory oxygen concentration 14.5% experiment 2) on a simple test of cognitive performance (the time needed to read briefly displayed letters). 3. Under both hypoxic conditions the time needed to read briefly presented letters decreased, from 12.1 +/- SD 3.8 ms to 8.3 +/- 1.5 ms (P < 0.01) in experiment 1, and from 11.9 +/- 1.9 ms to 8.1 +/- 1.1 ms (P < 0.01) in experiment 2. 4. A rapid and mild hypoxic challenge seems to improve a simple measure of cognitive performance above normal values. The common notion that exposure to hypoxia and altitude invariably impairs cognitive performance may have to be re-evaluated.

Adult↗
PubMed1991

[Khat, a herbal drug with amphetamine properties].

Because of their stimulating effect, leaves of the khat bush are chewed in several East African countries and in Yemen. Since only fresh leaves are active, this habit is almost unknown outside the regions where the plant grows. Recently, however, khat has made its appearance in the United States and in several European countries, while an import permit has been requested in Switzerland. These are reasons for making the practitioner familiar with the effects of this drug. During the last fifteen years, knowledge of khat and its constituents has made substantial progress. Today, the alkaloid cathinone is regarded as the main active principle of this drug, and this substance is held to be a natural amphetamine. This article summarizes knowledge of the pharmacology of khat.

Africa, Eastern↗
PubMed1991

Visual masking: a reliable measure for the assessment of cognitive dysfunction in the elderly?

Reliable assessment of cognitive dysfunction in the elderly is a prerequisite for the evaluation of treatment of age-related cognitive decline. Psychophysical thresholds are known to be more reliable than psychometric tests, as assessed by stability of performance in visual masking. A backward (Till & Franklin, 1981) and a forward masking study (Coyne, 1981) were replicated. Thereafter, the same volunteers carried out a backward and forward masking task adapted to minimize noncognitive age-related influences: target and mask duration were individually adjusted to control for reduced eye transmissiveness. Attention was assessed with the electrooculogram; a dependent variable insensitive to sporadic decreases of attention was selected. Test-retest stability in the elderly after 2-4 weeks was r = .97 in backward and r = .86 in forward masking. As Alzheimer's disease mainly affects the cortex, backward masking, which is primarily cortical, may be useful to assess aspects of cognitive dysfunction.

Adult↗
PubMed1991

[Orthotopic liver transplantation at the Island Hospital. Initial experiences 1985-1990].

Between 1985 and 1990 22 orthotopic liver transplantations (OLT) were realized in 19 patients. Active infection and diffuse splanchnic venous thrombosis were the only contra-indications to the intervention. Sixteen patients were transplanted electively; three had to be retransplanted urgently. Three patients had an urgent primary transplant. The incidence of surgical complications related to liver implantation was fair. One patient (5%) developed a late portal vein thrombosis; another patient (5%) had to be retransplanted because of hepatic artery thrombosis. All patients presented one or more major postoperative complications. All, but one, patients had a rejection of the allograft; five of them needed treatment with mono- or polyclonal antilymphocytic sera to reverse the rejection. One patient was retransplanted because of a hyperacute rejection. The six-month survival in this series is 68.5% (13 of 18 patients); one patient died 7 months post-OLT due to a neurological complication of her Wilson disease. Quality of life (from 6 to 64 months post-OLT) is excellent in the 12 long-term survivors. This small experience of the Bernese transplantation program shows that liver transplantation is a safe surgical procedure allowing excellent quality of life in a majority of patients.

Adult↗
PubMed1990

Excessive motor impairment two hours after triazolam in the elderly.

The pharmacokinetics of triazolam 0.25 mg p.o. and psychomotor coordination were compared in nine healthy, elderly volunteers and nine middle aged controls. Motor coordination, as measured by pursuit rotor performance, was impaired in the elderly even before triazolam administration, and in contrast to the controls it deteriorated to a critical level after the drug. Factors associated with the major decrease in psychomotor performance in the elderly volunteers were poor baseline performance, an additional independent-age factor, and the plasma concentration of free triazolam. Although short acting benzodiazepines may have a less detrimental effect on performance on the morning following their intake, there may be serious motor incoordination and falls may occur if the patients have to rise during the night, particularly when the plasma concentration is high, i.e. about 2 h after dosing.

Adult↗
PubMed1990

Amphetamine-like effects in humans of the khat alkaloid cathinone.

1. The chewing of khat leaves as a stimulant is common in certain countries, and the effects of this material are supposed to be due to the phenylalkylamine alkaloid cathinone. In order to determine the effects of this substance in humans, a single oral dose of cathinone or placebo was administered to six healthy male volunteers in a double-blind, random order crossover study. 2. Cathinone produced increases in blood pressure and in heart rate, and these changes were concomitant with the presence of cathinone in blood plasma. 3. The physical and mental changes that the subjects reported during the experiment indicated that cathinone has in humans euphorigenic and psychostimulant effects. 4. These observations support the assumption that cathinone is the constituent mainly responsible for the effects of khat, and they show that this alkaloid has also in humans amphetamine-like effects.

Administration, Oral↗
PubMed1990

[Diagnosis and treatment of alcoholism: psychiatric aspects].

The image of the chronic alcohol patient has changed. Diagnosis is only possible if the doctor assumes alcohol abuse in all his patients. The diagnosis can only be made taking psychiatric, somatic and psychosocial aspects into consideration. Because of the tendency of the patient to deny, an independent history is necessary. Questionnaires, such as the 'Münchner Alkoholismustest', may be helpful. Therapy by the family physician is initiated with a careful somatic, psychiatric and psychosocial work-up, counselling and care. An important factor is the close collaboration between physician and social worker.

Alcohol Drinking↗
PubMed1989

Ethological studies in animals and man, their use in psychiatry.

Ethology is concerned with the observation, description and measurement of the acts and postures which make up the behavioural repertoire of animals. Man too, exhibits analogous patterns of non-verbal behaviour, many of which serve social interactions. It is shown how ethological profiles of psychiatric patients can be constructed using the same methods as are used to analyse the social behaviour of rodents. It is argued that deficits in social behaviour are a key feature of the mentally ill patient and arise when flight, i. e. escape-oriented behaviour predominates. This notion is supported by an ethological study which shows that compared to healthy subjects, depressed patients exhibit fewer facial expressions and gestures which instigate or invite social interactions. These patterns serve to isolate the depressive patients from the group. With its emphasis upon objective analysis of behaviour, the ethological approach can provide a useful adjunct to conventional but largely subjective, clinical assessment schemes. It can also help to integrate findings in man and animals since in both, the behaviour is assessed in the same kind of units according to a common conceptual framework.

Animals↗
PubMed1988

[HIV infection of the central nervous system: psychiatric consequences].

Cerebral infection with human immunodeficiency virus can result in the development of symptoms covering a wide spectrum of psychiatric disorders and including adjustment disorders, affective disorders, delirium and dementia. The rapid and insidious nature of the disease requires an approach that relies on differential diagnosis, thorough psychiatric and neurological examination and, when indicated, additional tests such as EEG, LP, CT or MRI. The treatment of psychiatric symptoms is based on traditional pharmacological principles, although at lower doses due to the patients' propensity to develop delirium. Supportive psychotherapy and education of the patient and his family on the special aspects of HIV-associated psychiatric disorders are also cornerstones of treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Sleep and sleep disorders].

Disturbance of sleep is a symptom of heterogeneous origin. Hypersomnia (excessive sleep during daytime) must be carefully distinguished from hyposomnia. Hypersomnic patients should be referred to a neurologist for further diagnostic workup; hypnotics may be dangerous in these patients. Medical, psychiatric and other cases of hyposomnia should be identified and treated as part of a comprehensive therapy plan. Counselling and application of the rules of sleep hygiene should be considered. When drug therapy is indicated, benzodiazepines are preferable. Because chronic insomnia causes serious impairment to the quality of life, prolonged treatment with hypnotics is sometimes unavoidable. However, their long term efficacy remains to be demonstrated.

Circadian Rhythm↗
PubMed1987

[Cardiovascular and metabolic changes in the antabuse-alcohol reaction: basis for the diagnosis of degree of severity].

The clinical symptoms and signs, certain metabolic aspects (including ethanol, acetaldehyde and glucose concentrations in plasma) and hemodynamic parameters (cardiac rate, blood pressure and cardiac output) were assessed in 16 ambulatory alcoholics (3 female, 13 male, average age 46 years) following pretreatment with disulfiram (total dose 1.2 to 2.4 g) and oral administration of 0.2 g ethanol 94% per kg body weight. Since the only selection criterion for inclusion was a diagnosis of alcohol dependence (DSM III, 303.9), the group was heterogeneous and exhibited a variety of concomitant diseases such as alcoholic liver disease in 9, chronic bronchitis in 5 and arterial hypertension in 3. Whereas peak plasma alcohol concentrations were comparable (median: 0.33 mg/ml; range: 0.19 to 0.40) in all subjects, peak acetaldehyde levels varied over 40-fold (median 5.1 micrograms/ml; range: 0.2 to 8.8). In consequence, there were marked interindividual differences in cardiovascular reaction, in contrast to the virtually constant finding of flush, palpitations and dyspnoea. Since the decrease in peripheral vascular resistance (to a median of 46% of control) was only in part compensated by increased cardiac output (median: 161%), both systolic and diastolic blood pressures were reduced by 30 and 45 mm Hg respectively. In 4 patients systolic pressure fell to shock levels (less than 70 mm Hg). The presumed toxic effect of acetaldehyde is again supported by close correlations between acetaldehyde plasma concentrations and the changes in blood pressures and peripheral resistances. We were able to demonstrate that disulfiram-induced inhibition of hepatic microsomal function - measured with the aminopyrine breath test - predicts the expected acetaldehyde peak levels following ethanol administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaldehyde↗
PubMed1986

Light treatment of seasonal affective disorder in Switzerland.

Seasonal Affective Disorder (SAD) has been characterised by two or more depressive episodes in autumn or winter (with remission the following spring or summer), decreased energy, increased sleep, increased appetite, weight gain and carbohydrate craving. SAD patients were identified in a Swiss-German population; 22 participated in a light-therapy protocol (1 week bright white light 2,500 lux or dim yellow light 250 lux, from 06-08 h and 18-20 h). Both observer and self-ratings indicated a significant diminution of depressive symptoms with both lights. One week after withdrawal from yellow light, depression ratings relapsed to previous values; remission lasted longer after bright white light. Global VAS self-rating scales for "mood" and "well-being" however, and the Hamilton scale for atypical SAD symptoms, differentiated clearly between bright and dim light: only bright light showed an improvement that persisted after withdrawal. These results suggest that even though a placebo effect cannot be excluded, 4 h explicit light exposure/day may not be a negligible quantity. Light treatment promises to be a useful non-pharmacological intervention in certain forms of depressive illness.

Adult↗
PubMed1986

[Effect of psychotropic drugs on information processing].

Although psychopharmacology relies heavily upon precise, objective measurement of drug effects, the latter remain phenomenological unless they are relatable to clinically relevant disorders. Consequently, ideal drug testing procedures should not only be based upon understandable physiological principles, but also afford accurate, unequivocal measurement of parameters in models which are available in both animals and humans. In recent years the study of information processing via the peripheral visual system has emerged as a promising model having at least some of the aforementioned features. Much is known about the physiological characteristics of animal visual pathways. It is a unique property of the visual system, that the neurophysiological measures in animals find their analogue in the psychophysical measurements which can be carried out with great precision in humans. This relationship may be used to compare effects of drugs in neurophysiological studies of animals with their influence on perceptive phenomena in humans. However, whereas the animal peripheral visual system has been used to assess drug effects on information processing, there is a paucity of such studies in humans.

Animals↗