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Biomedical subjects

W Bernhard

Publications and source records attributed to W Bernhard.

At least 37 records · Page 2Linked to original sources
PubMed1994

High-performance liquid chromatographic analysis of phospholipids from different sources with combined fluorescence and ultraviolet detection.

An isocratic high-performance liquid chromatographic (HPLC) system was developed for the separation of major phospholipid classes, i.e., phosphatidylcholine, sphingomyelin, lysophosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine. Phospholipids were detected with ultraviolet absorption at 205 nm and subsequent fluorescence detection. Fluorescence of the phospholipids (excitation, 340 nm; emission, 460 nm) was achieved by postcolumn formation of mixed micelles with 1,6-diphenyl-1,3,5-hexatriene. For ultraviolet absorption there were great differences depending on the saturation of phospholipid fatty acids but for fluorescence the sensitivity was almost identical for all phospholipids except phosphatidylinositol and lysophosphatidylcholine. Dipalmitoylphosphatidylcholine showed nearly no ultraviolet but good fluorescence response. Ultraviolet to fluorescence ratio was characteristic for different phospholipids and for identical phospholipids from different sources. Quantification of phosphatidylcholine and phosphatidylethanolamine with HPLC using N-monomethylphosphatidylethanolamine (dioleoyl) as an internal standard gave the same results as phospholipid phosphorus quantification after thin-layer chromatography.

Chromatography, High Pressure Liquid↗
PubMed1994

beta-Adrenergic priming of rats in vivo modulates the effect of beta-agonist in vitro on surfactant phospholipid metabolism of isolated lungs.

To evaluate the effects of multiple beta-adrenergic stimulations on pulmonary surfactant phospholipids, perfused lungs from beta-adrenergic primed and non-primed rats were challenged with the beta-agonist terbutaline in vitro. Cell-free lung lavage, lavagable alveolar cells and lung tissue were analysed for phospholipid content and incorporation of precursors. In lung lavage, terbutaline in vitro doubled the incorporation of 14C-choline and 3H-palmitate into total phosphatidylcholine (PC) and of 3H-palmitate into phosphatidylglycerol (PG). beta-adrenergic priming in vivo prior to terbutaline in vitro lowered the increase of precursor incorporation. For lavagable cells, terbutaline in vitro increased the incorporation of 3H-palmitate into PC. Priming in vivo reduced this effect and diminished the specific 3H-choline incorporation into lavagable cell PC below control level. For lung tissue, priming increased the amounts of PC and disaturated PC (DSPC) whereas terbutaline in vitro decreased DSPC in both primed and non-primed lungs. Terbutaline in vitro slightly increased the incorporation of 14C-choline and 3H-palmitate into PC and DSPC in non-primed but not in primed lungs. beta-adrenergic blockade by ICI 118.551 prevented all effects but generally increased 3H-palmitate incorporation into the phospholipids and, in lavagable cells, the amount of PC. We conclude that long-term beta-adrenergic treatment may alter the metabolism of pulmonary surfactant phospholipids by increasing tissue PC and DSPC and by decreasing the secretion of newly-synthesized PC.

Adrenergic beta-Antagonists↗
PubMed1994

Phospholipid synthesis in isolated porcine gastric mucous cells.

Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are the major phospholipids of the gastric mucosal surface barrier and chiefly originate from mucous cells. Among these phospholipids PC with palmitic acid as its hydrophobic moieties is believed to protect the gastric mucosa by its hydrophobic properties. We investigated the phospholipid synthesis of isolated porcine gastric mucous cells in vitro and incubated them in the presence of radiolabelled precursors. Incorporation of 3H-choline into PC and of 14C-ethanolamine into PE was linear at 1, 10, and 100 mumol/l substrate concentration for at least 6 h. Half-maximal rate of precursor incorporation was achieved at 21 and 15 mumol/l of choline and ethanolamine, respectively. Ethanolamine inhibited PC synthesis and choline inhibited PE synthesis. A small amount of radioactivity originating from 14C-ethanolamine and from the methyl groups of 3H-methionine were incorporated into PC. Palmitic acid was incorporated into PC more than PE. Indomethacin did not influence the de novo synthesis of PC and PE via the Kennedy pathway, but inhibited the incorporation of 3H-methionine into PC. These results indicate that in gastric mucous cells PC and PE synthesis de novo depends on the concentrations of choline and ethanolamine. The palmitic acid content of PC depends on the availability of palmitic acid as a substrate: indomethacin-induced mucosal damage is not explained by modulation of phospholipid synthesis de novo.

Animals↗
PubMed1993

Impaired regulation of surfactant phospholipid metabolism in the isolated rat lung after nitrogen dioxide inhalation.

Various drugs have been shown to stimulate surfactant phospholipid metabolism. Particularly beta-adrenergic agonists play an important role under physiologic conditions. For the first time we have studied whether nitrogen dioxide (NO2) inhalation alters beta-adrenergic regulation of surfactant phospholipid metabolism in the model of the isolated lung. Rats were continuously exposed in vivo to a 5 ppm NO2-containing atmosphere for 48 hr. The lungs were isolated and perfused in presence of the beta-adrenergic agonist dopexamine and surfactant metabolism was studied in three lung compartments: (1) lung lavage, (2) lung tissue, and (3) lavagable free alveolar cells. We found that (1) in normal rat lungs dopexamine increased the incorporation of palmitate and choline from the perfusate into lung lavage phospholipids. In nitrogen dioxide exposed rat lungs beta-adrenergic stimulation did not cause an increase in precursor incorporation. No significant difference in unstimulated precursor incorporation was found for normal and NO2-exposed rat lungs. (2) Lung tissue from rats exposed to NO2 showed a decreased precursor incorporation into disaturated phosphatidylcholine due to an augmented cellular pool size. (3) Lavagable alveolar cells showed an increased palmitate uptake after nitrogen dioxide inhalation and by beta-adrenergic stimulation. From these data we conclude that nitrogen dioxide inhalation impairs the beta-adrenergic regulation of surfactant phospholipid metabolism. Moreover these data underline the importance of beta-adrenergic agonists in surfactant metabolism.

Administration, Inhalation↗
PubMed1993

Shigella flexneri transformants expressing type 1 (mannose-specific) fimbriae bind to, activate, and are killed by phagocytic cells.

Shigella flexneri M90T (invasive) and BS176 (noninvasive) are typical nonfimbriated organisms that do not bind to or activate phagocytic cells. We demonstrate that S. flexneri M90Tp and BS176p, obtained by transformation of the strains named above with the cluster of genes encoding type 1 (mannose-specific) fimbriae of Escherichia coli, express the functional fimbriae, as shown by electron microscopy, by binding of antifimbria antibodies and by yeast cell aggregation. The transformants, but not the parental strains, bound to human granulocytes and mouse peritoneal macrophages. This binding was inhibited by methyl alpha-D-mannoside but not by methyl alpha-D-galactoside. The bound bacteria induced oxidative burst activation and degranulation of the granulocytes in vitro. With mouse peritoneal macrophages, the binding of the fimbriated bacteria induced degranulation in vitro. Injection of the bacteria into mouse peritoneum also induced degranulation of the macrophages in vivo; no such effect was observed with the nonfimbriated strains. The bound fimbriated transformants were effectively killed by the human granulocytes in vitro in the absence of opsonins or after opsonization with human anti-S. flexneri antiserum. The nonfimbriated strains were killed only after opsonization. These results provide further evidence for the role of type 1 fimbriae in lectin-mediated nonopsonic phagocytosis.

Animals↗
PubMed1992

Some anthropological aspects of the prehistoric Tyrolean ice man.

The corpse of a Late Neolithic individual found in a glacier in Oetztal is unusual because of the intact nature of all body parts that resulted from the characteristics of its mummification process and its protected geographical position with regard to glacier flow. Anthropological data indicate that the man was 25 to 40 years old, was between 156 and 160 centimeters in stature, had a cranial capacity of between 1500 and 1560 cubic centimeters, and likely died of exhaustion.

Animals↗
PubMed1992

Lectinophagocytosis of type 1 fimbriated (mannose-specific) Escherichia coli in the mouse peritoneum.

Bacteria can bind specifically to phagocytic cells via lectin-carbohydrate interactions and such binding is often followed by activation and degranulation of the phagocytes, as well as uptake and killing of the bacteria, a phenomenon designated lectinophagocytosis. Although extensively studied in vitro, no direct evidence for the occurrence of lectinophagocytosis in vivo has been available. To obtain such evidence, we injected type 1 fimbriated (mannose-specific) or nonfimbriated Escherichia coli into the peritoneal cavity of mice (10(7)-10(10) bacteria/animal) in the absence or presence of sugars and quantified the phagocytic activity by assaying the release of lysosomal N-acetyl-beta-D-glucosaminidase into the peritoneal fluid, up to 45 min after injection. Following injection of the type 1 fimbriated bacteria, significant release of the enzyme was observed which was time dependent and increased with the number of bacteria injected, whereas the nonfimbriated bacteria caused only little release. Methyl alpha-D-mannoside (50 mM), but not methyl alpha-D-galactoside or sucrose, inhibited the release by 60 to 100%. No release of N-acetyl-beta-D-glucosaminidase was induced by bacteria injected into a peritoneal cavity from which the macrophages had been removed. Our findings show that lectinophagocytosis can occur in vivo and may contribute to the host's defence against type 1 fimbriated bacteria.

Acetylglucosaminidase↗
PubMed1991

[The body muscle compartment and its relationship to food absorption and blood chemistry during an extreme endurance performance].

The purpose of the study was to examine the changes of the muscle's fat-free compartment and its relation to the corresponding biochemical and nutritional parameters of 42 men and 13 women, the participants of an ultra long-distance run of 1000 km (20 days of daily running 50 km). The muscle-fractions initially increased, decreased in the middle phase, and remained stable for the rest of the run. Significant changes of the fat-free weight were registered from the 11th day on, the LBM decreasing until the middle of the distance; then the lean body mass enlarged. All the muscle-circumferences were reduced with the exception of the thigh, which grew, paralleling the CK/CKMB-concentrations, this phenomenon being due to the high mechanical stress of the lower extremities. The biochemical parameters exhibit a strain-related reaction of adaptation within the initial 6 days, the hormones and protein-concentration increasing in the beginning and falling from the third day on, uric acid and CK/CKMB-activity decreasing from the 6th day on. The consecutive parallel reduction of both uric acid, urea, and muscle measurements might be seen as a special endurance-related clearance-mechanism of potential toxicants. The negative relationship between the changes of muscle measurements and the cumulative protein intake and the catabolic constellation of the clinical-chemical values might suggest that the absolute protein intake of 1.7 g/kg body mass should be increased in order to diminish the loss of musculature during an ultra-long distance run.

Absorption↗
PubMed1991

[Changes in foot dimensions during extreme endurance running].

55 (including 13 women) of 110 starters of a 1000-km-ultra long distance run reached their goal after 20 days of daily running 50 km. As a consequence of the burden of running 500 km the flat feet form is diminished, which might be caused by an increased reactive muscular tonus. The increase of foot length and breadth measures between the 9th and 16th day, however, demonstrates the opposite effect, when a "physiological limit" of circa 500 km is exceeded.

Anthropometry↗
PubMed1989

Altered regulation of beta-amylase activity in mutants of Arabidopsis with lesions in starch metabolism.

Three classes of mutants of Arabidopsis thaliana (L.) Heynhold with alterations in starch metabolism were found to have higher levels of leaf amylase activity than the wild type when grown in a 12-hr photoperiod. This effect was dependent upon the developmental stage of the plants and was largely suppressed during growth in continuous light. The various amylolytic activities in crude extracts were separated by electrophoresis in nondenaturing polyacrylamide gels and visualized by activity staining. The increased amylase activity in the mutants was due to an up to 40-fold increase in the activity of an extrachloroplast beta-amylase (EC 3.2.1.2). These observations indicate the existence of a regulatory mechanism that controls the amount of beta-amylase activity in response to fluctuations in photosynthetic carbohydrate metabolism. It is paradoxical that beta-amylase appears to be a highly regulated enzyme, but as yet no physiologically relevant function can be assigned to this enzyme due to the absence of starch in the cytoplasmic compartment of leaf cells.

Journal Article↗
PubMed1989

Degradation of vasoactive intestinal peptide by isolated, ventilated, and perfused rat lungs.

The degradation of vasoactive intestinal peptide (VIP) was studied using an isolated perfused rat lung model. 125iodine labelled VIP (125I-VIP) was used as a tracer. VIP was cleared from the perfusate by a single lung passage up to concentrations of 1 nmol l-1. The clearance rate was decreased at higher concentrations of VIP. VIP was taken up by the lung tissue and the cleavage products were re-extruded into the perfusate. The time delay of re-extrusion was increased at starting concentrations of VIP exceeding 1 nmol l-1 and in the presence of the lysosomal inhibitor chloroquine. After a bolus of 9 pmol or 40 nmol 125I-VIP into the pulmonary artery catheter 6.3 pmol or 2920 pmol, respectively, were bound by the lung. Most of the radioactive material was extruded within 25 min and consisted of low molecular weight 125I-labelled degradation products. We conclude that the receptors for VIP in the alveolar capillaries are of high affinity and capacity to extract VIP from the circulation and that lysosomes may be involved in the degradation. The degradation products are of low molecular weight.

Animals↗
PubMed1988

[Comparative studies of the population structure of a Kurd village population in Southeast Turkey. I. Morphologic regional comparison].

The paper is dealing with an anthropological investigation of a Kurdish village population from southern Turkey. We especially attached importance on the complete registration of all inhabitants to get a reliable sample for regional comparison of morphological features. Anthropological data of other Kurdish population groups are used for univariate and multivariate analysis. The resulting clusters are discussed beside the question of representation under the standpoint of regional and cultural origin of the samples.

Anthropometry↗
PubMed1987

[Correlates and predictors of the age of menarche].

In a cross-sectional study of 452 girls between 10 and 16 years of age 36 indices of physical and 50 of mental development were tested for their correlation with age at menarche and chronological age, as well as for their predictive power for estimating menarche by multiple regression analysis. Indices of physical maturity and body weight when adjusted for chronological age showed the highest partial correlation coefficients with age at menarche. Among mental characters which show lower intercorrelations with menarche occurred the highest correlation coefficients for a handmotor factor "Spurennachzeichnen" and a factor "Gruppenabhängigkeit" (which indicates a type of social motivation). In general physical and mental factors correlate higher with chronological age than with age at menarche. By multiple regression analysis we determined 14 physical and 25 mental predictors explaining 21% and 17% respectively of the variance of age at menarche. The error of the estimate predicting menarche on body weight without knowledge of onset of menarche is +/- 1 year. Using chronological age in a sample of girls before menarche the error of the estimate only is +/- 6 months. To compare the predictive power of chronological age combined with body weight or with skeletal age the time interval is calculated within which 95% of girls attain menarche. The range of prediction extends from 4.3 to 1 year on chronological age (11-16 years); using mean body weight it can be improved by 1.8 to 6 months, while using mean skeletal age an improvement of 0.2 to 3.9 months is possible compared with body weight. The correlations between age at menarche and physical and mental variables are attributed to a common hormonal influence on rate of development.

Adolescent↗
PubMed1986

[Physical and psychological changes in relation to the period before and after onset of the menarche].

This cross-sectional study on 452 girls between 11 and 16 years of age examines the physical and psychological changes in the period 30 months before and 60 months after onset of menarche. Indicators of maturity showed the strongest alterations around menarche. In the majority of the physical characters (e. g. thickness of skinfold) adult values are achieved only a longer period after menarche, whereas others (e. g. dimensions of the head) terminate growth already largely by onset of menarche. We found out a minimum in development of thickness of skinfold at the time of menarche indicating a "second loss of body fat" in girls. In four different dimensions of personality (health, anxiety, neuroticism, power of concentration) menarche causes an interruption of the psychic development, and that in an adverse sense.

Adolescent↗
PubMed1983

Ethnogenesis of South Asia with special reference to India.

An attempt has been made to illustrate the quite complicated process of ethnogenesis in South Asia from the viewpoint of physical anthropology. The numerous invading waves which reached the Indian subcontinent from the northwest played an important role in this process. Most important for the ethnogenesis of South Asia was the invasion of Indo-Aryan groups in the middle of the 2nd millenium B.C. known from historical sources. In large parts of the Indo-Pakistan region they assimilated the aboriginal population in ethnic, cultural and linguistic respects in the course of time. Furthermore, the ethnogenesis of the Indian region is determined by the caste system of Hinduism which, however, is not as rigid as generally assumed. There are numerous evidences that since more than 2000 years a slow but steady process of assimilation and integration of tribal groups, living in the forest areas of Central India, into the Hindu caste system took place, a process which is still going on. It is intended to demonstrate to what degree the ethnogenetic processes in South Asia, known from prehistoric and historical sources, can be traced in human skeletal findings of different time periods as well as in the anthropological structure of the living population. Finally, hypotheses and theories, especially those of Risley and von Eickstedt are discussed, who attempted to interpret the great variability of anthropological and morphological traits in the Indian subcontinent by taking into consideration the existence of different old population substrata and their mixing and assimilation.

Asia↗
PubMed1981

Effect of quinacrine on nuclear structure and RNA synthesis in cultured rat hepatocytes.

The effects of quinacrine, an antimetabolite which intercalates into DNA, on the ultrastructure of interphase nuclei and on RNA turnover were studied in primary cultures of rat hepatocytes. Procedures included ultrastructural cytochemical staining for ribonucleoprotein and DNA, autoradiography, and measurement of labeled uridine uptake and incorporation. Addition to the culture medium of a nontoxic dose (10 microM for 30 min) reduces the net accumulation of labeled uridine in RNA. This involves first heterogeneous RNA and then ribosomal RNA since their structural precursors, interchromatin fibrils and nucleolar fibrils, respectively, diminish in that order. Intranucleolar chromatin retracts, and perinucleolar chromatin becomes unusually condensed. A toxic dose (50 microM for 30 min) produces greater inhibition of tritiated uridine incorporation in RNA. This precedes and is not due to a drop in uridine uptake into the cells. Toxic doses produce unusually large clusters of interchromatin granules which are embedded in an unusual dense material which stains positively for ribonucleoprotein. Three regions of the chromatin are altered. (a) Perinuclear condensed chromatin retracts from the nuclear envelope, remaining attached by short DNA-containing bridges. (b) The normally dispersed nucleoplasmic chromatin condenses into a stainable network which retracts centrifugally. (c) Perinucleolar chromatin becomes a network of small highly condensed masses or bands interconnected by fibrils which are either decondensed or stretched. These alterations in chromatin structure probably form the basis of quinacrine-impaired nuclear metabolism.

Animals↗
PubMed1980

[Distribution of ABO blood groups and incidence of Rh factor (D) in various ethnic groups in the Hindu Kush region (Kafirs, Kalash Chitrali)].

With the aid of Eldon cards the distribution of the ABO blood groups and of the Rh factor (D) was investigated in different native ethnic groups (Kafirs, Kalash, Chitrali) in the Hindu Kush region of Afghanistan and Pakistan. All studied groups are characterized by a relatively high frequency of blood group gene A and extremely low frequencies of B and O. This distribution differs appreciably from that of the rest of the Indian subcontinent as well as that of the adjacent Central Asiatic areas. The possible causes of the exceptional position of the native Hindu Kush groups in the ABO blood group system are discussed. It may be assumed that selection as a result of mother-child compatibility played a role as will be shown in a later paper. Concerning the studied traits of the Rhesus system, all investigated groups fit in the range of variation of the South Asian area.

ABO Blood-Group System↗