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Biomedical subjects

A Schmidt

Publications and source records attributed to A Schmidt.

At least 667 records · Page 37Linked to original sources
PubMed1982

Emission of Hydrogen Sulfide by Leaf Tissue in Response to l-Cysteine.

Leaf discs and detached leaves exposed to l-cysteine emitted a volatile sulfur compound which was proven by gas chromatography to be H(2)S. This phenomenon was demonstrated in all nine species tested (Cucumis sativus, Cucurbita pepo, Nicotiana tabacum, Coleus blumei, Beta vulgaris, Phaseolus vulgaris, Medicago sativa, Hordeum vulgare, and Gossypium hirsutum). The emission of volatile sulfur by cucumber leaves occurred in the dark at a similar rate to that in the light. The emission of leaf discs reached the maximal rate, more than 40 picomoles per minute per square centimeter, 2 to 4 hours after starting exposure to l-cysteine; then it decreased. In the case of detached leaves, the maximum occurred 5 to 10 h after starting exposure. The average emission rate of H(2)S during the first 4 hours from leaf discs of cucurbits in response to 10 millimolar l-cysteine, was usually more than 40 picomoles per minute per square centimeter, i.e. 0.24 micromoles per hour per square decimeter. Leaf discs exposed to 1 millimolar l-cysteine emitted only 2% as much as did the discs exposed to 10 millimolar l-cysteine. The emission from leaf discs and from detached leaves lasted for at least 5 and 15 hours, respectively. However, several hours after the maximal emission, injury of the leaves, manifested as chlorosis, was evident. H(2)S emission was a specific consequence of exposure to l-cysteine; neither d-cysteine nor l-cystine elicited H(2)S emission. Aminooxyacetic acid, an inhibitor of pyridoxal phosphate dependent enzymes, inhibited the emission. In a cell free system from cucumber leaves, H(2)S formation and its release occurred in response to l-cysteine. Feeding experiments with [(35)S]l-cysteine showed that most of the sulfur in H(2)S was derived from sulfur in the l-cysteine supplied and that the H(2)S emitted for 9 hours accounted for 7 to 10% of l-cysteine taken up. (35)S-labeled SO(3) (2-) and SO(4) (2-) were found in the tissue extract in addition to internal soluble S(2-). These findings suggest the existence of a sulfur cycle which converts l-cysteine to SO(4) (2-) through cysteine desulfhydration.

Journal Article↗
PubMed1982

The effect of sodium cromoglycate delivered by Spinhaler and by pressurized aerosol on exercise-induced asthma in children.

Sixteen children completed a randomized placebo-controlled double-blind study comparing the efficacy of pre-treatment with (1) 20 mg sodium cromoglycate (SCG) powder delivered by Spinhaler, (2) 2 mg SCG delivered by pressurized aerosol and (3) placebo. The drug was administered 15 min before the 6 min of treadmill-running performed at the same time of day on 3 consecutive days in a climate chamber with a temperature of 23 degrees C and a relative humidity of 40%. All the patients, none of whom were taking systemic steroids, had shown a post-exercise fall in peak expiratory flow (PEF) of more than 15% from baseline when tested one day prior to the study. On the day with no pre-treatment the average post-exercise fall in PEF was 46% (+/- 4) (mean +/- s.e. mean). After pre-treatment with SCG powder the average fall in PEF was 21% (+/- 3), after pre-treatment with SCG aerosol the fall was 22% (+/- 3) and after placebo a post-exercise fall of 31% (+/- 5) was seen. Both forms of SCG were significantly better than pre-treatment with placebo. Comparing no pre-treatment with pre-treatment with placebo revealed a statistically significant difference (P less than 0 . 001) indicating a placebo effect. It is concluded that this study design has a marked placebo effect. Both pre-treatment with 2 mg SCG delivered by pressurized aerosol and 20 mg delivered by Spinhaler is superior to placebo in conferring protection against exercise-induced asthma (EIA). No bronchodilating effect was seen in the first 15 min after administration of the drug.

Administration, Intranasal↗
PubMed1982

[Absorption of isosorbide dinitrate in guinea-pig intestine and in the colon of sheep (author's transl)].

Segments of the intestine of anaesthetized guinea-pigs and the colon of conscious sheep were perfused with saline containing 0.1--25 mg/l 1,4:3,6-dianhydrosorbitol-2,5-dinitrate (isosorbide dinitrate, ISDN). The increase in ISDN uptake was linearly related to its concentration. Absorption was rapid. In the jejunum and the ileum of guinea-pig, 7% of perfused ISDN was absorbed per 10 cm of intestine in the proximal and 15% in the distal colon, respectively. In the total colon of sheep, 83% disappeared during the perfusion. Per unit of length, surface or dry weight of mucosa the net flux of ISDN in the small intestine was only half that in the colon. Absorption from the colon per unit of wet weight of the gut was only slightly higher compared to the small intestine. 1 h after the infusion of 14C-labelled ISDN into the large intestine of sheep filled with normal contents 14C-activity was detected in the plasma, a maximum was reached after 4 h. Renal excretion of ISDN or its 14C-labelled metabolites was parallel to the ISDN concentration in blood. Microbial degradation of ISDN to CO2 in colon contents was insignificant.

Animals↗
PubMed1982

[The effect of benzarone on serum lipids and arterial wall of cholesterol fed rats].

Rats of BD X strain and SHR/NIH Montreal Ingelheim strain (genetic hypertension) received a diet containing 3.9% cholesterol or 3.7% cholesterol plus 0.6% benzarone, respectively, and libitum for 5 or 9 months. The following chemical and ultrastructural results were obtained. 1. The cholesterol-benzarone diet causes a body weight reduction of 10%, a relative increase of serum HDL and a corresponding decrease of serum LDL and VLDL, as compared with the effects of the cholesterol diet. No differences of total serum cholesterol and serum triglycerides between the two groups were observed. 2. The aorta of cholesterol fed animals shows a slight but statistically not significant increase of total cholesterol content. 3. No differences in the composition of connective tissue components (collagen, elastin, uronic acid content) between the cholesterol fed animals and a control group on normal diet could be detected. 4. Electron micrographs of several vessel wall areas from cholesterol fed hypertensive animals revealed fibrosis, necrosis of media muscle cells and an increase of matrix vesicles. Severe damages were found in coronary arteries and in the caudal arteries. 5. Cholesterol feeding of hypertensive rats increases the cholesterol content of liver 10fold and the triglycerides content 3fold as compared with liver lipids of control rats. Benzarone application to cholesterol fed rats effects a statistically significant decrease of liver cholesterol and triglycerides.

Animals↗
PubMed1982

Influence of temperature and relative humidity of inhaled gas on exercise-induced asthma.

The decrease in pulmonary function, expressed as peak expiratory flow, which is seen in some asthmatics after exercise (exercise-induced asthma (EIA)), has been studied under conditions standardized with regard to ventilation during exercise, room temperature and relative humidity of the inhaled air. Exercise was performed under four different conditions. 1) temperature (T) 15 degrees C and relative humidity (RH) 30%, and 2) T 15 degrees C and RH 70%, 3) T 30 degrees C and RH 30% and 4) T 30 degrees C and RH 70%. Treadmill running was performed on four succeeding days at the same time of day with the four different combined conditions. Identical ventilation during the exercise was secured on each day by monitoring respiratory frequency, tidal volume, minute ventilation and accumulated ventilation. A significantly smaller decrease in pulmonary function occurred when both T and RH were high, whereas the decrease in pulmonary function after exercise was identical when either temperature or relative humidity, or both, were low. It is concluded that the water concentration of the inspired air is negatively correlated to the decrease in pulmonary function after exercise in asthmatics.

Adolescent↗
PubMed1982

Exercise-induced asthma after swimming and bicycle exercise.

Eleven adult patients with exercise-induced asthma (EIA) were subjected to swimming and bicycle exercise under controlled conditions regarding temperature and relative humidity of the inhaled air, the respiratory frequency, tidal volume, minute ventilation and the accumulated ventilation. Swimming for 6 min was performed on the first day, and the next day the patients performed bicycle exercise. On both days the temperature of the inhaled air was 23% C and the relative humidity 15%. The average accumulated ventilation for the 6 min of exercise was 404 l for bicycle exercise and 419 l for swimming. The decrease in pulmonary function was 31% after bicycle exercise and 30% after swimming. It is concluded that the stimuli for EIA are equally effective whether exercise is performed in the form of swimming or bicycling.

Adolescent↗
PubMed1982

Exercise-induced asthma after walking, running and cycling.

Bronchial response to 6 min exercise performed as treadmill-walking, treadmill-running, ergometer bicycling and free running were compared in 11 subjects with exercise-induced asthma (EIA). The study was performed under control of air temperature and relative humidity. The three different types of exercise were performed on consecutive days, and the ventilation was monitored using pneumotachography and rating of perceived exertion (RPE). The decrease in peak expiratory flow after treadmill-running was 25.5 +/- 4.5% (mean +/- SEM), after bicycle ergometer exercise 26.0 +/- 3.0%, after treadmill-walking 26.0 +/- 3.0% and after free running 27.0 +/- 3.5%. No statistical difference in bronchial response was demonstrated between the four types of exercise. The total ventilation for the 6 min period of exercise was 421, 411 and 427 litres for treadmill-walking, treadmill-running and bicycle ergometer exercise, respectively. It is concluded that the type of work is of little importance in EIA.

Adult↗
PubMed1982

Effect of physical training on peak oxygen consumption rate and exercise-induced asthma in adult asthmatics.

Sixteen adults with perennial asthma were trained for 2 months using heavy exercise. Eleven comparable subjects performing light exercise with the same frequency and duration served as controls. After the training the peak oxygen consumption rate (Vo2max) was increased by 10% (P = 0.02) in the heavily trained group, whereas no significant change was observed in the control group. The difference in Vo2max between males and females averaged 20% and is thus of the same magnitude as found in healthy subjects. An exercise-induced asthma (EIA) test comprising 6 min of free running was carried out in all participants in both training groups before and after the training period. The post-exercise decrease in pulmonary function assessed by peak expiratory flow (PEF) was 36 + 4% (mean +/- SEM) before heavy training and 33 +/- 2% after two months of training (paired t-test: P = 0.18); for the control group the decrease was 40 +/- 6% and 40 +/- 7% (P = 0.22), respectively, at the pre- and post-training investigation. It is concluded that physical training may increase the Vo2max in asthmatic patients by the same amount as in normal subjects, whereas no influence on the degree of EIA could be detected.

Adolescent↗
PubMed1982

Surgery for gallstones in old age: do we operate too late?

Out of 59 patients of 70 years of age or more submitted consecutively to operative treatment for gallstone disease, 25 patients (42%) had histories of more than one year's duration. Jaundice had been present or was observed in 32 patients (54%) and acute cholecystitis was found in 21 (41%). Choledocholithiasis was found in 32 patients (54%). The patients with complications had significantly longer had symptoms of gallstones than patients without complications. The mortality was 12% (7 patients). Four of these were submitted to operation as an emergency and three were submitted to operation subacutely because of deterioration in their general condition. In cases submitted to elective operation the mortality was thus nil. On the basis of these results and review of the literature, it is concluded that complications of gallstone disease are less well tolerated in elderly patients than in younger patients. In cases where elective operation is possible, elderly patients seem to have just as good a prognosis as slightly younger age groups. Our material seems to indicate that, probably because of their age, elderly patients have their operation postponed despite symptoms of gallstones, until a complication occurs. If this is so it might be questioned whether we operate on these patients too late.

Acute Disease↗
PubMed1981

[X-linked mental retardation and X-chromosome fragile sites (author's transl)].

One of the commonest forms of mental retardation can now be especially diagnosed by differentiated chromosome analysis: X-linked heritable mental retardation with a fragile site on the X-chromosome. The fragile site on the distal long arm of the X-chromosome in region 2, band 7 (Xq27) is not apparent under normal circumstances of culture but must be provoked by folic acid deficiency in the culture medium. The marker X-chromosome is demonstratable in 4-56% of the metaphases in affected males, whereas the recognition of heterozygote gene carriers is still uncertain. In the hemizygotes the defect is characterised clinically by a usually moderately severe intellectual retardation. The character of the carriers is friendly, and well balanced. Speech development is greatly retarded. Testicular volume beyond puberty is increased. Heterozygote females are usually clinically unremarkable. At times a slight mental retardation has been described.

Culture Media↗
PubMed1981

Phosphate ester groups in proteoglycans from bovine nasal cartilage.

1. Proteoglycan subunits isolated by standard procedures from bovine nasal cartilage, previously incubated in the presence of [32P]phosphate contain [32]-phosphate ester groups as a regular structural component. 2. Contamination of the proteoglycan subunit with 32P-labeled nucleic acids could be excluded by repeated cesium chloride density gradient centrifugation under associative and dissociative conditions, lanthanum chloride precipitation, gel filtration and by the resistance of the proteoglycan subunit associated 32P to phosphoric diester hydrolases. 3. The [32P]phosphate ester groups are associated to the chondroitin sulfate peptide fraction obtained by proteolytic digestion of the proteoglycan subunit molecule. Degradation of the chondroitin sulfate peptide by chondroitinase ABC resulted in a 32P-labelled oligosaccharide peptide fraction, that contains xylose, galactose, glucuronic acid and inorganic phosphate in a molar ratio 1 : 2 : 1 : 0.12. 4. 32P radioactivity is released as inorganic phosphate by treatment of the 32P-labelled oligosaccharide peptide with acid phosphatase or alkali.

Acid Phosphatase↗