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Biomedical subjects

A Honig

Publications and source records attributed to A Honig.

At least 73 records · Page 4Linked to original sources
PubMed1995

Cardiorespiratory responses to acute hypoxia and hyperoxia in adult and neonatal spontaneously hypertensive and normotensive rats.

The aim of this study was to investigate whether there are differences between particular characteristics of breathing regulation in primary hypertensive and normotensive states which might indicate significant differences in arterial chemoreceptor reflex function. Under air-breathing conditions, minute ventilation was similar in adult spontaneously hypertensive rats (SHR) (50 +/- 2ml/min x 100 g) and in Wistar-Kyoto rats (WKY) (54 +/- 3 ml/min x 100 g) but significantly lower in randomly bred normotensive Wistar rats (NWR) (39 +/- 1 ml/min x 100 g). In seven-day-old rats minute ventilation was 10.5 +/- 1.2ml/min x 10 g in SHR and 10.2 +/- 1.4 ml/min x 10 g in 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 and neonatal animals. Acute inhibition of ventilation caused by hyperoxia indicated that oxygen dependent peripheral chemoreceptor activity during air-breathing was similar in SHR and normotensive controls both in the unanesthetized neonatal state and in anesthetized adult animals. No well defined association between the characteristics of the hypoxic ventilatory response and primary hypertension could be demonstrated although responses in adult anesthetized SHR tended to be faster and of higher amplitude than in normotensive controls.

Acute Disease↗
PubMed1994

Demonstration of temperature dependence of Na(+)-K+ pump activity of human blood cells.

In our physiology laboratory course we introduced several simple but instructive experiments in which medical students make observations on their own blood cells. In this experiment, students measured and discussed the effect of different temperatures on Na+ and K+ distribution between blood cells and plasma. In venous blood of 35 female and 64 male students, plasma (extracellular) [Na+] and [K+] were measured with ion-selective electrodes immediately after blood sampling and successively four times in intervals of 1 h in three samples stored at 1, 20, and 37 degrees C. At 1 degree C, plasma [K+] increased significantly and nearly linearly with cooling time of the blood, whereas plasma [Na+] decreased. In contrast, at 37 degrees C plasma K+ levels significantly decreased in the first 2 h and then stabilized at new levels clearly below baselines. At 1 degree C blood cells had a greater K+ loss in women than in men, whereas at 37 degrees C the K+ loss was significantly less pronounced in women. Plasma Na+ did not significantly change at 37 degrees C. This remarkably reproducible experiment demonstrates the existence of active Na(+)-K+ transport in human blood cells by showing medical students, with their own blood, that the basal chemical processes of such pumps are inhibited at a temperature of 1 degree C and stimulated when blood temperature is slightly higher than the usual body temperature.

Adult↗
PubMed1992

Physical illness in chronic psychiatric patients from a community psychiatric unit revisited. A three-year follow-up study.

A group of 156 psychiatric patients from an urban community psychiatric unit for chronic psychiatric patients was routinely medically screened and reported on. Re-evaluation of the medical diseases found in those patients was carried out three years later. Those who were still being treated--73 patients (47%)--were interviewed, as were their psychiatrist and, where necessary, their general practitioner (GP). The implementation of medical recommendations given following the physical screening by the specialist in internal medicine was also assessed. Re-evaluation of the diagnoses confirmed that 36% of this population had one or more physical diseases, rather than the 53% found earlier. The results show that the majority of physical complaints and diseases as well as functional illnesses were as persistent as the psychiatric diagnoses in this patient group. The patients' GP seems to be the person best suited as the primary physician responsible for the patient's physical health.

Chronic Disease↗
PubMed1992

Coping with hearing voices: an emancipatory approach.

A questionnaire comprising 30 open-ended questions was sent to 450 people with chronic hallucinations of hearing voices who had responded to a request on television. Of the 254 replies, 186 could be used for analysis. It was doubtful whether 13 of these respondents were experiencing true hallucinations. Of the remaining 173 subjects, 115 reported an inability to cope with the voices. Ninety-seven respondents were in psychiatric care, and copers were significantly less often in psychiatric care (24%) than non-copers (49%). Four coping strategies were apparent: distraction, ignoring the voices, selective listening to them, and setting limits on their influence.

Adaptation, Psychological↗
PubMed1991

Muscle lactate transport studied in sarcolemmal giant vesicles: dependence on fibre type and age.

Lactate transport was studied in sarcolemmal giant vesicles obtained from rat or rabbit skeletal muscle. With this technique it is possible to obtain quantitative information on sarcolemmal transport characteristics. In equilibrium exchange experiments with 10, 30 and 60 mM lactate, vesicles from 'red' rat muscles had a 50% higher lactate transport capacity than vesicles from 'white' muscles. Giant vesicles made from rabbit red muscles had a 39% higher lactate transport capacity than vesicles from white muscles. These differences probably reflect a different number of lactate transporters, whereas the lactate affinity in red and white muscles are identical. Lactate transport capacity decreased with age. Sarcolemmal giant vesicles made from 22-month-old rats had a 28% lower transport capacity than vesicles from 2-month old rats. In absolute terms, the initial exchange flux with 30 mM lactate was 92 and 127 pmol cm-2 sec-1 for old and young rats, respectively. In supplementary studies in which microelectrode measurements were made in single mouse muscle fibers, it was shown that the cellular acidification rate due to lactate incubation, was 38% lower in fibres from 18-month old mice than in fibres from 2-month old mice.

Aging↗
PubMed1990

Hormonal and renal responses to arterial chemoreceptor stimulation by almitrine in healthy and normotensive men.

Healthy and normotensive men (n = 11) were hospitalized and kept under controlled fluid and sodium intake (120 mequ/d) for 5 days. Their systemic arterial blood pressures as well as heart and breathing rates were measured, and venous blood and urine samples were collected at intervals of 1-4 h. Diuresis was induced by scheduled drinking of tea (150 ml/h). Electrolytes, osmolality, and creatinine were determined in both plasma and urine samples. Aldosterone, cortisol, and vasopressin concentrations were measured only in the plasma. On the 2nd and 3rd day of the experiments the participants received orally either a placebo-pill or 100 mg almitrine bismesylate (Vectarion). Each subject was tested in a placebo- and an almitrine experiment. The subjects responded to the almitrine treatment with a suppression of the plasma aldosterone content, a transient rise of glomerular filtration rate, a natriuresis and an increase of renal concentrating ability. In the placebo-experiments, only the transient rise of filtration rate was significant. The data indicate that almitrine, by stimulating the peripheral arterial chemoreceptors, suppresses plasma aldosterone and inhibits renal proximal sodium reabsorption by so far unknown mechanisms. They also suggest that oral and intravenous almitrine administrations, respectively, might differently affect renal hemodynamics and excretory function.

Adult↗
PubMed1990

Influence of sorbitol and mannitol on the reactions of kidney excretory function evoked by arterial chemoreceptor stimulation with almitrine in anaesthetized and artificially ventilated cats.

The reactions of renal hemodynamics, as well as of excretory and concentrating function (clearance-technique) in response to arterial chemoreceptor stimulation by almitrine bismesylate were studied in 3 groups of chloralosed, relaxed, and constantly ventilated cats. In 2 groups of chemoreceptor-intact animals an osmotic diuresis was induced by intravenous infusion of an isoionic solution containing equivalent amounts of either sorbitol or mannitol. Under similar conditions the 3rd series of experiments was carried out in cats under mannitol diuresis but with deafferented arterial chemoreceptors. The changes of mean arterial and central venous pressures as well as of the parameters of the arterial acid-base balance were similar in all groups of cats studied. The chemoreceptor-intact animals undergoing sorbitol diuresis did not show any natriuresis in response to the drug but reacted with a remarkable increase in their U/Posm and TCH2O/Cosm ratios. In contrast, the chemoreceptor-intact animals infused with mannitol in saline reacted to almitrine with a transient natriuresis but with only a weak increase in their U/Posm and TCH2O/Cosm ratios. The data suggest that arterial chemoreceptor stimulation inhibits proximal tubular sodium reabsorption. In the sorbitol-experiments during chemoreceptor stimulation the enhanced delivery of sodium by the proximal fluid was reabsorbed in the thick ascending limb of Henle's loop thus increasing medullary osmolality and renal concentrating ability. Mannitol apparently limited this additional sodium reabsorption in the thick ascending limb of Henle's loop; therefore in the mannitol-experiments during chemoreceptor stimulation a natriuresis but only relatively weak changes of renal concentrating function occurred. The data also suggest that a pharmacological chemoreceptor stimulation might support the recovery of renal excretory function post-anaesthetically, although the optimal solution infused to induce an osmotic diuresis remains to be determined.

Almitrine↗
PubMed1989

Peripheral arterial chemoreceptors and reflex control of sodium and water homeostasis.

In response to acute exposure to moderate high-altitude hypoxia, mammals increase their blood hemoglobin concentration very rapidly by reducing their plasma volume. This phenomenon is caused not only by a redistribution of the body fluid volumes but also by a suppression of voluntary sodium and water intake as well as an inhibition of renal tubular sodium reabsorption with natriuresis and diuresis. This article reviews the role of the peripheral arterial chemoreceptors within the framework of the reflex mechanisms that might cause the changes in sodium and water metabolism in acute arterial hypoxia. The evidence that the peripheral arterial chemoreceptors do also influence sodium and water homeostasis in normoxia is presented. The interrelations between carotid body structure and arterial chemoreceptor reflex effects on the one hand and primary systemic hypertension on the other are discussed.

Animals↗
PubMed1989

The influence of consensus on the assessment of physical disease in chronic community psychiatric patients.

Physical disease is a frequent concomitant of mental disease. The majority of chronic psychiatric patients have physical complaints. Screening physical disease on a regular basis in an ambulatory setting for chronic psychiatric patients is often impossible if only for lack of medical manpower and facilities. Especially for the nonmedical personnel of a community psychiatric unit (CPU) for chronic patients, approaching and handling physical complaints and diseases poses a formidable problem. This paper addresses the issue of screening physical disease from a completely different viewpoint than that of the often advocated but just as often infeasible routine physical examination and laboratory workup. It is argued that consensus (i.e., agreement and mutual understanding) between patient and therapist on the physical well-being of the patient may increase the accuracy with which a CPU therapist, irrespective of his/her discipline, assesses physical disease. This hypothesis was tested in a sample of 156 chronic ambulatory psychiatric patients. Consensus between patient and CPU therapist was measured by means of a questionnaire. The CPU therapist assessment on physical disease in both the consensus and no consensus group was compared with those of two external medical observers; the patients' general practitioner and a specialist in internal medicine, who followed a protocolized physical screening procedure. The results tend to support the proposed hypothesis. Replication of this study using a larger samples is recommended in order to confirm the value of consensus in the assessment of physical disease in at least some subgroups of chronic ambulatory psychiatric patients and for the implications that consensus could have for daily community psychiatric practice.

Adult↗
PubMed1989

Physical illness in chronic psychiatric patients from a community psychiatric unit. The implications for daily practice.

The prevalence and significance of physical diseases, and health-care-seeking behaviour, were examined in a sample of 218 chronic psychiatric patients from an urban community psychiatric unit. Only 14% declined medical screening. Of the respondents, 53% had one or more probable or certain physical diseases warranting further medical attention. The majority of the diseases found were minor and typical of primary care problems. A severe (i.e. life-threatening) disease was present in 7% of respondents. Of the patients, 87% visited their GP at least once a year. The implications are that frequent consultation with primary care specialists and health-care-seeking behaviour should be noted, and included in any evaluation of the medical needs of chronic patients in community psychiatric care.

Community Mental Health Centers↗
PubMed1988

Amino acid levels in depression: a preliminary investigation.

Plasma, cerebrospinal fluid and brain tissue amino acid levels were measured in 14 patients with affective illness and generally confirm previous findings. There was no correlation between these values and age, sex, family history and levels of anxiety. GABA levels measured in cortex tissue were negatively correlated with depressive mood (P less than 0.05), supporting a possible involvement of GABA in depressive illness.

Adult↗