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Biomedical subjects

H Noack

Publications and source records attributed to H Noack.

At least 37 records · Page 2Linked to original sources
PubMed1995

Cytochrome-c oxidase in developing rat heart. Enzymic properties and amino-terminal sequences suggest identity of the fetal heart and the adult liver isoform.

Perinatal development of cytochrome-c oxidase (complex IV) and ubiquinol-cytochrome-c reductase (complex III) was investigated in rat heart and liver by analysing catalytic properties, protein amounts, and subunit isoforms during the transition from the fetal to the adult state. The total amounts of complexes from milligram quantities of tissue, and the portions of isoforms of complex IV, were quantified densitometrically after isolation of the native complexes by blue native polyacrylamide gel electrophoresis and separation of the protein subunits by Tricine/SDS/PAGE [Schägger, H. & von Jagow, G. (1991) Anal. Biochem. 199, 223-231]. A parallel increase of protein amounts and catalytic activities during perinatal development was observed in heart and liver for complex III, but only in liver for complex IV. In heart, both a doubling of the turnover number of complex IV and a lowered Km for cytochrome c were observed. The altered enzymic properties correlated with the increase of heart type subunits VIa and VIII. The fetal enzymes from heart and liver seem to be identical to the adult liver isoform, as deduced from their enzymic properties and identical aminoterminal sequences of subunits VIa and VIII.

Amino Acid Sequence↗
PubMed1995

[Sleep disorders in professional man and women and their relationship to the workplace].

In Switzerland as well as in many other industrialized countries, sleep disturbances are among the most prevalent health problems. Reliable knowledge about the social and personal conditions of sleep disturbances and especially about their association with conditions is however limited. Using data from the Bern workplace Health Project ("Härz-AsProjekt", n = 774) a logistic regression model was applied to study the association between an indicator of sleep disturbances composed both of problems falling asleep and problems waking-up during the night and several work-related factors. Sleep disturbances were found to be directly associated with perceived work load, time pressure and physical work demands and inversely associated with social acceptance at workplace, work satisfaction and the ability not to become immersed into work. Under comparable working conditions these associations did not differ for men and women. It was concluded that psychosocial demands and resources of the workplace do affect the quality of sleep.

Adolescent↗
PubMed1995

The relation of reported symptoms to social, individual, and behavioral indicators of ill-health: is the number of reported symptoms a unique general dimension of ill-health?

Counts of functional symptoms are an accepted measure of ill-health in general populations. However, their relation to other indicators of ill-health are still poorly understood. The aim of this study was to investigate such relations in order to reach a better understanding of the 'meaning' of the number of symptoms. The data analyzed was drawn from a telephone health survey conducted among a representative sample of 2111 Swiss adults as part of the Intercantonal Health Indicators Project in 1989. In a logistic regression analysis the Number of symptoms (a summery score of eleven severe function symptoms) was found to be strongly associated with eight social, behavioral, and psychological indicators of ill-health ('Unable to work', 'Frequently consulting a physician', 'Use of analgesics', 'Use of sedatives', 'Poor coping with ill-health', 'Social impairment', 'Poor health', and 'Poor psychological well-being'). To control for effects due to individual symptoms, they were included in the models by stepwise procedure. Although individual symptoms became predictive for all indicators (except for Poor coping with illness), the association between the Number of symptoms and the indicators (except for Social impairment) remained statistically significant. Despite methodological provisos our results seem to support an interpretation of the Number of symptoms as a distinct and general dimension of ill-health.

Adaptation, Psychological↗
PubMed1994

[3-dimensional topography of the optic papilla with laser scanning tomography: clinical correlation of cluster analysis].

BACKGROUND The evaluation of optic disc topography is essential for the clinical diagnosis of primary open angle glaucoma. The purpose of this study was (1) to establish a computerized cluster formation of optic nerve head topography based on quantitative three-dimensional parameter values and (2) to describe the resulting clusters according to morphological appearance and visual fields. PATIENTS AND METHODS 337 optic nerve heads (glaucomatous optic neuropathy (n = 99), glaucoma suspects (n = 159), normals (n = 79) were analyzed using laser scanning tomography. A hierarchical cluster analysis was performed based on standardized variables (optic disc area, rim area, area-ratio, cup depth, cup steepness, height variations along the contour-line). Visual fields were tested by computerized static threshold perimetry. RESULTS A seven cluster solution met the optimizing criteria. The characteristic morphology of the clusters can be described as "normal" (N), "normal, large" (NL), "supernormal" (SN), "pseudonormal" (PN), "glaucoma-like-flat" (GF), "glaucoma-like-steep" (GS) and "macropapillary" (M). Visual fields were normal in 180 eyes. 99 eyes had glaucomatous field defects, 58 eyes revealed isolated relative scotomas < 10 db. Presence and degree of visual field defects varied within the automatically classified optic disc groups considerably. Visual field defects were found in 7.7% (SN), 8.3% (N), 18.8% (NL), 33.3% (M), 37% (PN), 64.7% (GF) and 83.3% (GS) respectively. Pseudonormal discs were characterized by a flattening of the height variations along the disc border. CONCLUSIONS (1) Optic nerve heads may be automatically classified based upon a combination of three-dimensional topographic variables. (2) Analysis of optic disc topography and computerized perimetry are supplementary tools in the evaluation of the glaucoma patient. Visual field defects may be present within any cluster. However, the likelyness of the presence of visual field defects differs considerably among the topometrically defined groups of optic nerve heads. Functional damage is to be expected in association with reduced height variations along the disc border, a small rim area and a steep cupping of the optic nerve head.

Cluster Analysis↗
PubMed1994

Relations between tocopherol depletion and coenzyme Q during lipid peroxidation in rat liver mitochondria.

In order to evaluate different mitochondrial antioxidant systems, the depletion of alpha-tocopherol and the levels of the reduced and oxidized forms of CoQ were measured in rat liver mitochondria during Fe++/ascorbate and NADPH/ADP/Fe++ induced lipid peroxidation. During the induction phase of malondialdehyde formation, alpha-tocopherol declined moderately to about 80% of initial contents, whereas the total CoQ pool remained nearly unchanged, but reduced CoQ9 continuously declined. At the start of massive malondialdehyde formation, CoQ9 reaches its fully oxidized state. At the same time alpha-tocopherol starts to decline steeply, but never becomes fully exhausted in both experimental systems. Evidently the oxidation of the CoQ9 pool constitutes a prerequisite for the onset of massive lipid peroxidation in mitochondria and for the subsequent depletion of alpha-tocopherol. Trapping of the GSH by addition of dinitrochlorbenzene (a substrate of the GSH transferase), results in a moderate acceleration of lipid peroxidation, but alpha-tocopherol and ubiquinol levels remained unchanged when compared with the controls. Addition of succinate to GSH depleted mitochondria effectively suppressed MDA formation as well as alpha-tocopherol and ubiquinol depletion. The data support the assumption that the protective effect of respiratory substrates against lipid peroxidation in the absence of mitochondrial GSH is mediated by the regeneration of the lipid soluble antioxidants CoQ and alpha-tocopherol.

Animals↗
PubMed1993

[Health, health-related behavior and gainful employment].

Based on data collected in a survey as part of the Swiss Intercantonal Health Indicators Project (random sample stratified by age of 20-75 year old persons, n = 2106) relationships between level of employment (full, part-time, none) and health/disease as well as health behaviour were studied. Employed men and to some extent employed women as well were found to be less frequently sick and to feel more frequently well than non-employed men and women. Overall employment appears to affect health/disease in men more strongly than in women, whereas influence on health behaviour appears to be similar in both gender groups. The results of the study are discussed both with regard to further hypotheses of health research and opportunities of health promotion.

Adult↗
PubMed1992

Are large optic nerve heads susceptible to glaucomatous damage at normal intraocular pressure? A three-dimensional study by laser scanning tomography.

To evaluate the effects of the presence of glaucomatous visual field defects and of intraocular pressure elevations on optic nerve head topography, we analyzed 148 left optic nerve heads of 148 patients using laser scanning tomography. The optic discs are classified according to computerized static perimetry and documented IOP readings: 101 discs show normal visual fields (36 normal discs, 22 ocular hypertensives, 28 normotensive glaucoma suspects and 15 ocular hypertensive glaucoma suspects), 47 discs (34 high-pressure glaucoma discs, 13 normal-tension glaucoma discs) demonstrate glaucomatous visual field damage. A two-way analysis of variance discloses significant differences (P < 0.01) between the groups of optic discs classified according to perimetry for most topometric parameters evaluated except for disc area. Classification according to documented IOP (cut off at 21 mmHg) results in larger disc areas in normotensive discs compared to hypertensive optic nerve heads in the study population. Results suggest that large discs may be susceptible to glaucomatous visual field damage at statistically normal IOP readings.

Adult↗
PubMed1992

Evaluation of a procedure for the simultaneous determination of oxidized and reduced pyridine nucleotides and adenylates in organic phenol extracts from mitochondria.

An extraction procedure using mixtures of phenol, chloroform, and isoamyl alcohol originally applied to quench mitochondria for determining adenylates proved suitable also for the quantification of reduced and oxidized pyridine nucleotides yielding recoveries of more than 90%. In combination with HPLC, this approach allows the simultaneous determination of NAD+, NADP+, NADH, and NADPH as well as of adenylates within one extract. A comparison of this extraction method with fluorimetric measurements of pyridine nucleotide reduction in intact mitochondria revealed that about 30% of the fluorescence signal in the resting state of liver mitochondria is caused by NADPH.

Adenine Nucleotides↗
PubMed1992

[Courses in health education as interventions in industry].

Following a brief overview of approaches to workplace health promotion and more specifically of health education courses the paper describes the objectives, contents and methods of a new health course for workers at elevated health risk. This course was developed as part of a comprehensive workplace intervention programme. It comprises three consecutive modules, coping with stress, nutrition, and fitness, each consisting of five 75-minute lessons. Due to intervals of several months between the modules the whole course takes about a year. Course objectives are to improve awareness of own health-related life-style, to mobilise health resources and to develop potentials for health action. Instructional methods include teaching of relevant knowledge, exchange of experience, observational tasks as well as practical exercises.

Curriculum↗
PubMed1991

Coupling of spectrin and polylysine to phospholipid monolayers studied by specular reflection of neutrons.

The technique of specular reflection of neutrons is applied for the first time to study the charge-dependent interaction of the protein spectrin and the polypeptide poly-L-lysine with model phospholipid monolayers in the condensed phase state. We first established the structure of a pure monolayer of dimyristolyphosphatidylcholine (DMPC) in both the expanded and condensed fluid phase states without protein in the subphase. The thickness of the hydrocarbon chains increases from 11.4 +/- 1.5 A in the expanded state to 15.8 +/- 1.5 A in the condensed state, whereas the head group region is approximately 10 A thick for both phase states. When spectrin is present in the subphase, the dimensions of DMPC in the condensed state are not significantly affected, but there is approximately 0.09 volume fraction spectrin in the head group region. Lipid-spectrin coupling is enhanced by electrostatic interaction, as the volume fraction of spectrin in the head group region increases to 0.22 in a mixed monolayer of DMPC and negatively charged dimyristolyphosphatidylglycerol in the condensed state. In contrast to spectrin, polylysine does not penetrate the head group region, but forms a layer electrostatically adsorbed to the charged head groups.

Biophysical Phenomena↗
PubMed1991

[Volumetric analysis of the optic papilla using laser scanning tomography. Parameter definition and comparison of glaucoma and control papilla].

We performed a three-dimensional structure analysis of the optic disc in 65 eyes of 65 patients (38 glaucoma patients, 27 control-group patients) using laser scanning tomography. Patients classified as glaucoma showed at least 3 points with a relative scotoma of -10 db loss or greater compared to age matched controls on static 30 degrees computerized perimetry. Control-group patients showed no relative scotoma outside the blind spot area compared to age matched controls. One way analysis of variance revealed statistically significant differences between the glaucoma (G) and the control-group (C) for excavation volume (+0.57 +/- 0.37 mm3 G/0.31 +/- 0.27 mm3 C, p less than 0.01), for the 3rd moment of the frequency distribution of excavation depths readings (-0.01 +/- -0.12 G/-0.13 +/- -0.09 C, p less than 0.001), area ratio (0.75 +/- 0.15 G/0.57 +/- 0.16 C, p less than 0.001), depth area ratio (0.35 +/- 0.24 G/0.18 +/- 0.12 C, p less than 0.001). A stepwise discriminant analysis classified 32 of 38 (84.2%) glaucoma discs and 21 of 27 (77.8%) control-group discs by a linear combination of 5 out of 15 topographic parameters. The results suggest that a combination of topographic parameters may provide an objective optic disc classification.

Computer Graphics↗
PubMed1991

[Modification of coronary arteriosclerosis in man by calcium antagonists?].

Calcium channel blockers may retard development and progression of coronary arteriosclerosis in man because of protective effects on membranes, (especially the endothelium), relaxation of vessel walls, inhibition of various platelet functions, impairment of proliferation and migration of smooth muscle cells in the vessel wall, and an improvement of vascular cholesterol metabolism. In animal trials development of atheromas in large arteries induced by cholesterol-rich food and other stimuli of atherogenesis could be successfully retarded by a broad variety of calcium channel blockers. Some clinical observations in patients with coronary artery disease pointed at positive effects of calcium antagonists in coronary arteriosclerosis. To date, the results of three prospective placebo-controlled trials with calcium antagonists in coronary arteriosclerosis are available. In all trials progression of atherosclerosis was assessed by serial angiograms: 1) INTACT (nifedipine: 20 mg four times daily; observation period: 3 years, two coronary angiograms); 2) Study of the Montreal Heart Institute (nicardipine: 30 mg three times daily; observation period: 2 years, two coronary angiograms); 3) FIPS (Frankfurt Isoptin Progression Study) (verapamil: 120 mg three times daily; observation period: 3 years, three coronary angiograms). Target variables in these studies were progression or regression of preexisting lesions, development of new lesions and the incidence of vessel occlusions. The INTACT and the Nicardipine studies preferably included patients in early stages of coronary artery disease. The patients of FIPS who were entered into the study immediately after coronary bypass surgery suffered from severe, advanced coronary artery disease. In the latter study progression of coronary artery disease was assessed separately in different vascular regions (bypassed and non-bypassed segments) and in the bypass grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium Channel Blockers↗
PubMed1991

[Determinants and educational approaches to AIDS anxiety in adolescents].

On the basis of a questionnaire filled out by 480 adolescents determinants of fear of AIDS were evaluated with a model of linear structural equations. The main factors that appeared were knowledge about AIDS (those who know more report less fear), personal involvement (those who are confronted more with the problem of AIDS report more fear) and sexual experience (those who are sexually more experienced report less fear). The last finding is interpreted to the effect that mainly sexually inexperienced adolescents, who are usually also the younger ones, shift their sexual fears to the AIDS-complex.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Randomized comparative study of secondary prevention of Pneumocystis carinii pneumonia in patients with acquired immunologic deficiency syndrome].

Pneumocystis carinii pneumonia is one of the most frequent infectious complications in patients with the acquired immunodeficiency syndrome (AIDS). A prospective trial was initiated to compare azidothymidine alone with azidothymidine plus aerosolized pentamidine as a secondary prophylaxis for pneumocystis carinii pneumonia. 27 patients (24 male, three female, average age 39 years) were enrolled, 14 patients receiving azidothymidine and pentamidine aerosol and 13 azidothymidine alone. After 166 days of follow-up, this trial had to be terminated prematurely, since the efficacy of pentamidine aerosol in the prevention of pneumocystis carinii pneumonia was clearly demonstrated in two recently published studies. Two patients died during the study period, one in either group, but neither due to pneumocystis carinii pneumonia. Two patients developed histologically proven pneumocystis carinii pneumonia; both patients were allocated to the azidothymidine arm. Pneumocystis carinii pneumonia was suspected clinically but not proven in four patients, three were randomized in the azidothymidine arm. Pentamidine was well tolerated and produced no severe side effects. The sample size is too small to draw definitive conclusions concerning the efficacy of pentamidine aerosol in AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Retardation of development and progression of coronary atherosclerosis: a new indication for calcium antagonists?

Development of atherosclerotic lesions in animals, preferrably induced by a high-cholesterol diet, can be successfully suppressed by calcium channel blockers such as verapamil, nifedipine, nicardipine and diltiazem. The issue of a beneficial effect of calcium channel blockers on human coronary atherosclerosis is however not yet settled. At present, three prospective randomized clinical trials with calcium channel blockers (Nifedipine, Verapamil, Nicardipine) are being conducted (INTACT, FIPS, Study of the Montreal Heart Institute). Target variable for assessment of progression in these studies is the severity of coronary atherosclerosis evaluated by angiography both at entry into the study and after 2-3 years of treatment. A total of 445 patients after coronary bypass surgery (CABG) were entered in FIPS (Frankfurt Isoptin Progression Study) and randomly allocated to either verapamil 120 mg t.i.d. or placebo. The extent of coronary atherosclerosis is assessed by repeat angiography both 1 year and 3 years after randomization. Three vessel regions are evaluated separately. 1. Native vessels without bypass grafts and segments distal to the peripheral graft anastomosis ("core region") 2. Segments bridged by bypass grafts and 3. Bypass grafts. The 1-year follow-up was completed by 162 patients (Group A = 80 patients; Group B = 82 patients). There was a homogeneous distribution in the two groups for all clinical variables, graft patency rates, and the incidence of clinical events (myocardial infarction, need for cardiac surgery or PTCA, cardiac death). The overall progression rate of atherosclerosis in the first year was expectedly low.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The reliability of psychophysiological examinations under field conditions: results of repetitive mental stress testing in middle-aged men.

In an epidemiological examination outside specialized laboratories we investigated the test-retest stability of blood pressure (BP) and heart rate (HR) reactions to standardized mental stress in 136 men (mean age 44 +/- 7 years) with complaints of mental and physical fatigue. Repetitive stress testing was performed at 4-week intervals on four occasions. On all four occasions stress levels differed significantly from baseline levels (P less than 0.001). Baseline conditions for BP and HR were significantly correlated at 4-week and 8-week intervals (P less than 0.001). Cardiovascular reactivity to mental stress was also stable over a 4, 8, and 12-week period. We conclude that psychophysiological reactivity can be assessed with good reliability under field conditions.

Adult↗