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Biomedical subjects

M Lehmann

Publications and source records attributed to M Lehmann.

At least 217 records · Page 12Linked to original sources
PubMed1991

[CT arthrography of the shoulder after surgical repair for ventral instability].

25 patients who had undergone a modified Lange repair were examined postoperatively after about four years, both clinically and by CT arthrography. Ventral redislocation was no longer seen postoperatively. As regards residual ventral instability, there was agreement between CT arthrography and the clinical findings in 20/25 patients (90%). Newly developed or residual dorsal instability could be accurately demonstrated by the presence of pathological changes of the dorsal labrum and by the observation of a wide dorsal joint recess. CT arthrography did not provide reliable evidence concerning loss of function and mobility of the treated shoulder. However, the presence of marked capsular folding suggests a poor clinical result.

Adult↗
PubMed1991

The maternally inherited regulation of P elements in Drosophila melanogaster can be elicited by two P copies at cytological site 1A on the X chromosome.

Two P elements, inserted at the cytological site 1A on an X chromosome from an Drosophila melanogaster natural population (Lerik, USSR), were isolated by genetic methods to determine if they are sufficient to cause the P cytotype, the cellular condition that regulates the P family of transposable element. The resulting "Lerik P(1A)" line (abbreviated "Lk-P(1A)") carries only one P element in situ hybridization site but genomic Southern analysis indicates that this site contains two, probably full length, P copies separated by at least one EcoRI cleavage site. Because the Lk-P(1A) line shows some transposase activity, at least one of these two P elements is autonomous. The Lk-P(1A) line fully represses germline P element activity as judged by the GD sterility and snw hypermutability assays; this result shows that the P cytotype can be elicited by only two P element copies. However, the Lk-P(1A) line does not fully repress delta 2-3(99B) transposase activity in the soma, although it fully represses delta 2-3(99B) transposase activity in the germline (delta 2-3(99B) is an in vitro modified P element that produces a high level of transposase activity in both the germline and the soma). The germline regulatory properties of the Lk-P(1A) line are maternally transmitted, even when the delta 2-3(99B) element is used as the source of transposase. By contrast, the partial regulation of delta 2-3(99B) somatic activity is chromosomally inherited. These results suggest that the regulatory P elements of the Lk-P(1A) line are inserted near a germline-specific enhancer.

Animals↗
PubMed1991

The monoclonal antibody RIB5/1--a useful completion of the MRC OX-3 and OX-6 haplotype specificity.

The haplotype binding pattern of a new mAb RIB5/1 against RT1 class II antigens on different tissues of inbred rat strains was investigated using the indirect POD-technique and a cytofluorometric analysis. RIB5/1 binds to a polymorphic determinant of the RT1 class II glycoprotein. Unlike MRC OX-3 (and OX-6), RIB5/1 reacts in optimal dilution with the RT1 haplotypes dvl, a, av, g, 1 but not with u. Therefore, the mAb pair MRC OX-3 (OX-6) and RIB5/1 is applicable for specific immunohistological purposes in chimaeric models with these RT1 haplotypes.

Animals↗
PubMed1990

[Humidifier syndrome as occupational disease in Switzerland].

Control of humidity may be necessary in various industrial processes. Contamination of humidifiers by algae and bacteria may lead in exposed workers to two distinct syndromes: extrinsic allergic alveolitis and humidifier fever. In Switzerland 18 cases of humidifier syndrome were accepted by SUVA as occupational disease. 13 of the 18 cases occurred in the printing industry. In 13 out of 18 cases contaminated humidifiers were the cause of the syndrome and in five cases contaminated air-conditioning systems. Due to the often uncharacteristic clinical signs and symptoms and variable clinical features diagnosis of humidifier syndrome was missed by the general practitioner. Once humidifier fever was clearly diagnosed most workers had to change their working place. Despite the avoidance of exposure respiratory problems, radiographic changes and pulmonary function changes often persisted. Major pulmonary function decreases resulting in pulmonary invalidity were observed in five of the 18 cases (28%). Technical measures to prevent humidifier syndrome are described.

Adult↗
PubMed1990

[Effect of beta blockade on hemodynamics in physical exertion].

Beta-receptor blocking agents are known for more than 20 years. They are of definite use in the therapy of arterial hypertension and coronary heart disease. Beta-blockers lower the sympathoadrenergic discharge to the heart and circulation, particularly if the former is increased. Beta-blockers induce a negative chronotropic and inotropic effect and inhibit beta 2-mediated vasodilation. Thus beta-sympathicolysis during physical activity results in damping of heart rate increase and of elevation of cardiac contractility. Systolic blood pressure does not increase much, and usually there is no decline in diastolic blood pressure, due to elevated peripheral resistance. With adequate dosage, there may even be a slight increase in diastolic pressure, an effect eventually vaning in chronic therapy. Pulmonary capillary wedge pressure is elevated to above normal via inhibition of contractility and relaxation of the heart. Stroke volume, cardiac output and the double-product decrease, the arteriovenous oxygen difference under exercise increases clearly and the maximum aerobic performance capacity decrease in healthy individuals. In coronary patients, this may protect against cardiac overload and increase symptom-free physical work capacity, due to a relative decrease in the myocardial O2 requirement and improved coronary perfusion resulting from prolonged diastole. With verified indication (hypertensive-hyperkinetic impairments of cardiovascular function, coronary heart disease), the goal is an overlapping, endurance-oriented training to reduce the overall sympathetic activation, in order to minimize medication in the long run.

Adrenergic beta-Antagonists↗
PubMed1990

Hypertension and sports activities: institutional experience.

Findings of 185 patients and 271 control subjects are presented for the assessment of work capacity in hypertensive individuals (primary hypertension); an attempt at classification by hypertensive stage is seen as an essential presupposition. The subdivision into three stages recommended by the Experts' Commission of the WHO places the effects of hypertension on the organism, especially on the heart, in the focal point. This appears justified from a prognostic, pathophysiological, and therapeutic point of view. Hemodynamics in the examined patients undergo increasing impairment in relation to the stage of hypertension with a decrease in maximum cardiac index and work capacity and an increase in myocardial oxygen requirement. Initially, only the diastolic cardiac function is impaired; however, in advanced stages, the systolic function of the heart is impaired as well. Evaluation of work capacity is usually possible from a cardiac point of view by means of noninvasive echocardiographic and spiroergometric methods. The mass/volume ratio of the left cardiac ventricle and the relationship between left ventricular muscle mass (or volume) and work capacity are especially important. Both experience characteristic changes depending on the stage of hypertension and thus permit precise determination of work capacity, progress controls, and delineation from physiological cardiac hypertrophy (athletic heart).

Cardiomegaly↗
PubMed1990

Recreational swimming in CHD patients and healthy control subjects in relation to left heart function.

We examined the influence on heart rate, blood pressure, lactate, glucose, and catecholamine levels of moderate recreational swimming at a mean time of 5.2 to 9 minutes with mean speed of 0.33 to 0.49 m/s in 25 CHD patients and 8 healthy control subjects. During swimming, changes in these exercise-related parameters were observed such as were only found in seated ergometry trials at levels above 100 to 175 W. We consider these changes tolerable for patients with mild left heart damage (n = 13; ejection fraction 54 +/- 7%; exercise capacity 2.1 +/- 0.4 W/kg). They may indicate overexertion in patients with marked damage to the left heart (n = 12; ejection fraction 44 +/- 5%; exercise capacity 1.3 +/- 0.4 W/kg). Six of the 12 patients with marked left heart damage stopped swimming before the planned time had elapsed for subjective (overexertion) or objective (arrhythmia) reasons.

Analysis of Variance↗
PubMed1990

Interval versus continuous exercise training after coronary bypass surgery: a comparison of training-induced acute reactions with respect to the effectiveness of the exercise methods.

In order to improve endurance by exercise on a bicycle ergometer, both the interval method (I) (exertion and recovery phases alternate each minute) and the continuous method (constant exertion) can be employed. We examined the effects of both methods on the following parameters: heart rate, blood pressure, rate-pressure product, glucose, lactate, and catecholamine levels, and physical performance. Two groups of nine male patients were trained daily on a bicycle ergometer for 3.5 weeks. These patients had undergone coronary bypass surgery 24 and/or 26 days before the training started. The training heart rate was set at 86% of the individual maximum heart rate. In the last week of training, the exercise intensity in both patient groups, following either I or C regimen, was 20:121 W and 83 W respectively. The exercise training lasted 20 minutes with the following findings: (1) there were no significant differences in blood pressure, rate-pressure product, rates of glucose and catecholamines, and (2) there was a significantly higher rate of lactate in the second ten minutes of the I training. Before and after the training period, the patients were subjected to a multistage bicycle ergometer exercise test (sitting). The following results obtained after the training favor the I method: (1) patients' physical performance increased (+0.63 vs. +0.26 W/kg; p less than 0.001); (2) heart rate was lower at rest (-9 vs. -4 beats/min; p less than 0.04) and at 75 W (-12 vs. -2 beats/min; p less than 0.02); (3) rate-pressure product was lower at rest (-1675 vs. -291; p less than 0.04) and at 75 W (-2810 vs. -735; p less than 0.05); (4) rate of lactate was lower at 75 W (-0.83 vs. -0.33 mmol/l; p less than 0.04); (5) catecholamines were not lowered by I or C training, and no differences between the two groups could be observed. Exercise training according to the I method involves both the aerobic and anaerobic capacity of the organism, whereas exercise training according to the C method involves only oxidative capacity. After coronary bypass surgery, the I method is better suited to increase physical performance and is more effective in economizing the cardiac function.

Adult↗
PubMed1990

Heart rates, cardiac arrhythmia, lactate levels and catecholamine excretions in CHD patients during cross-country skiing.

We examined cross-country skiing-related strain in 10 less experienced postinfarction patients, performing a skiing test, covering a distance of approximately 7 km in 90 min. Heart rates, cardiac arrhythmia, lactic acid levels and catecholamine excretions were determined as strain indicators. The patients' exercise capacity, estimated during graded ergometric cycling, was 2.1 +/- 0.4 watts.kg-1, indicating a nearly age-appropriate submaximum performance ability. They had suffered myocardial infarction 2.8 +/- 0.7 years previously, participated regularly in a rehabilitation program for at least one year, and they did not show coronary insufficiency or significant cardiac dysrhythmias during laboratory testing under their usual medications. They went cross-country skiing during a 4-day instruction period and subsequently performed a cross-country skiing test on the 5th day. Mean skiing-related heart rates (124 +/- 9 bpm) and adrenaline excretions (124 +/- 88 pmol.min-1) corresponded on average to an exercise level of 1.85-2.0 watts.kg-1 during laboratory testing, and mean noradrenaline excretions (586-343 pmol.kg-1) and lactate concentrations (3.83 +/- 2.18 mmol.l-1) to a level of 1.48-1.73 watts.kg-1. Cardiac dysrhythmias were observed in a moderate number of 6-8 SVES, 9 to 12 VES and 4 to 7 couplets of VES per 1000 beats during cross-country skiing. The present results point to a comparatively high cardiovascular strain in less experienced postinfarction patients during a cross-country skiing test at an intensity level thought to be moderate.

Adult↗
PubMed1990

[CT arthrography in the diagnosis of shoulder instability].

In the course of a prospective study, CT arthrography was carried out on 40 patients with shoulder instability. In 35 of these patients a lesion of the capsule and labrum was demonstrated, indicating glenohumeral instability; in three patients this was shown primarily by CT arthrography. In three patients, multidirectional instability was demonstrated. In four patients there was an isolated lesion of the labrum, whereas in one patient all the findings were normal. Compared with the capsulo-labral lesions, bone changes involving the head of the humerus and the glenoid were of lesser importance, although their severity affected the choice of operative treatment in four patients. Fifteen of the 40 patients have undergone surgery so far and in all cases the findings on CT arthrography could be confirmed.

Adolescent↗
PubMed1990

[Acute cardiovascular and metabolic changes in interval and endurance training in selected patients following aortocoronary bypass operation].

UNLABELLED: This study compared the acute changes of cardiovascular and metabolic reactions during interval and continuous training after coronary bypass surgery. Two groups of 9 male patients (age: 59 +/- 4 and 56 +/- 6 years, resp.) each trained on bicycle ergometer start on post-operative days 24 and 26, resp. In both training groups training heart rate was set at 86% of individual maximum heart rate. In the last week of training the exercise intensity in the group of patients who were trained by the continuous method was at 83 watts, and at 20:121 watts in the group of patients who were trained by interval method (rest:work each 1:1 min). At this exercise training that lasted for 20 min the acute response of heart rate, blood pressure, rate-pressure product, glucose, lactate and catecholamines was measured. RESULTS: In both methods there were no significant differences in systolic and diastolic pressure, rate-pressure product, in glucose or catecholamine levels. However, there was a significantly higher rate of lactate in the second 10 min of the interval training. And, in spite of higher peripheral exercise intensity by interval training, there was no higher cardiac work than by the continuous training. These findings suggest that interval training strains the oxidative capacity of the trained muscles in a more intensive and direct way than does continuous training.

Adult↗
PubMed1990

[Effects of interval versus endurance training of increasing performance, cardiovascular function, metabolism and catecholamines in selected patients after aortocoronary bypass operation].

This paper reports the effect of endurance exercise training on bicycle ergometer by interval method (work and interval each 1:1 min) and continuous method on increase of physical performance, decrease of heart rate, rate-pressure-product, glucose, lactate, and catecholamines. Two groups of nine male patients (aged 59 +/- 4 vs 56 +/- 6 (mean +/- SD)) after coronary bypass surgery each participated in the inpatient rehabilitation training. Training started 24 and 26 days, resp., after surgery and lasted for 3.5 weeks. Frequency and duration of exercise training: Monday-Friday 1 x 20 min and 1 x 25 min per day; Saturday/Sunday each 1 x 25 min per day. In the interval group and the continuous group the exercise training intensity was set at 86% of individual max. heart rate. In the last week of training mean exercise intensity was at 83 watts in the group of patients who were trained by the continuous method and at 20:121 watts in the group of patients who were trained by the interval method. Before and after the training period patients underwent a multistage bicycle ergometer exercise test in sitting position. Beginning at 25 w, each stage was increased by 25 w, whereby each stage lasted 3 min. Cutoff criteria were heart rate (220 - age x 0.85) and/or fatigue of the leg muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Catecholamine metabolism in heart failure patients and healthy control subjects.

Parameter of catecholamine metabolism were examined in patients (Groups II to V) in chronic, stable stages of coronary heart disease (n = 45), dilated cardiomyopathy (n = 17) and healthy control subjects (Group I). Plasma and urinary catecholamine patterns, catecholamine plasma half-life and catecholamine metabolism following administration of levodopa were determined. In cases of slight (Group II, ejection fraction (EF) 54 +/- 7%) to marked left-heart damage (Group III, EF 44 +/- 5%), the findings indicate elevated catecholamine excretion and a beginning reduction of plasma clearance as the cause of excessive, circulating and renally excreted catecholamines (applies to noradrenaline, less to adrenaline). The renal 24-h dopamine elimination is already slightly reduced in these patients. In cases of severe left-heart damage, the findings are not uniform. In some cases, noradrenaline at rest and at comparable exercise levels are elevated (Group IV, EF 20 +/- 11%), in some cases they are normal (Group V, EF 16 +/- 4%). The 24-h dopamine elimination is reduced in both groups to 34-41% of normal. Noradrenaline and adrenaline elimination is normal, or reduced (Group V, adrenaline). The exercise-induced, maximum plasma noradrenaline concentrations in Group IV and V are much lower (33-40% of normal) than in the healthy control individuals and patients in Groups II and III. Oral administration of 2-4 g levodopa per day result in a 20- to 40-fold dopamine increase in patients with heart failure (Group IV) and healthy control persons (Group I) (free and conjugated plasma dopamine, as well as free urinary dopamine).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Activity requirement for young domestic rabbits: raw fiber consumptionand animal welfare].

Swiss Animal Protection Regulations summon that the food provided shall be such as to permit the animals to satisfy their need for occupation combined with feeding. In intensive cage-keeping of fattening rabbits there is often no hay or straw fed in addition to the pellets, despite ethological evidence, that this does not fit their need for occupation. In a large semi-natural enclosure (600 m2) with grass and shrubs as well as feeding huts with pellets young rabbits at the age of 30-120 days are observed seven times from 6.00-21.00 h (N = 78 observations on 13 individuals). During this time they spend 81 +/- 37 minutes feeding on pellets and 92 +/- 47 minutes grazing, mainly early in the morning or late in the evening. In a group housing system for fattening rabbits (base 150 x 150 cm, two floors) the behaviour of 24 young rabbits from six different groups is surveyed in the region of the hay rack with a video camera. Two recordings during 24 hours in each group at the age of about 60 days (N = 48) show that in addition to feeding on pellets the animals engage with hay and straw for 111 +/- 45 minutes a day. The daily distribution shows maxima at dawn and dusk. The feeding patterns correspond to those observed in the semi-natural enclosure. Based on the ethological evidence and the Animal Protection Ordinance rabbits are to get additional straw or hay.

Animal Feed↗
PubMed1990

Suramin-treated HT29-D4 cells grown in the presence of glucose in permeable culture chambers form electrically active epithelial monolayers. A comparative study with HT29-D4 cells grown in the absence of glucose.

The clonal cell line HT29-D4 is able to differentiate by two different ways: i) by replacing glucose by galactose in the culture medium; ii) by addition of suramin (a drug known to interfere with the growth promoting activity of growth factors) in the medium. In both cases the transition in the organization of the cell monolayer occurred without cell loss. The two ways (i.e., glucose starvation or suramin addition) lead to polarized cells which generate electrically active cell monolayers (Fantini et al., Biol. Cell 65, 163-169 (1989) and this paper). Yet several important differences can be observed at the morphological or at the electrophysiological levels. 1) The suramin-treated cells (HT29-D4-S cells) organized into monolayers of high (40-50 microns) columnar cells while glucose-starved cells (HT29-D4-Gal cells) were rather cuboidal (20-25 microns). 2) HT29-D4-S cells were highly polarized; the nucleus was rejected at the basal side of the cell and lysosomes in the upper part of the cytoplasm. Numerous lipid-like droplets surrounded with glycogen were observed underneath the nucleus. HT29-D4-Gal cells never presented such a degree of organization. 3) The transepithelial resistance and the potential difference of HT29-D4-S monolayers reached values significantly higher than those for HT29-D4-Gal monolayers, reflecting a higher degree of organization. Specific proteins such as sucrase-isomaltase, alkaline phosphatase and carcinoembryonic antigen were localized exclusively on the apical membrane while human lymphocyte antigen (HLA) class I molecules were restricted to the basolateral membrane for both HT29-D4-S and HT29-D4-Gal cells. The present data demonstrate that the same cells can generate a different degree of cellular organization according to the experimental conditions of cell growth, the most elaborate state of differentiation being obtained in the presence of suramin.

Cell Division↗