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Biomedical subjects

K Weiss

Publications and source records attributed to K Weiss.

At least 109 records · Page 6Linked to original sources
PubMed1992

Synergism between PGE1-metabolites(13,14-dihydro-prostaglandin E1, 15-keto prostaglandin E1, 15-keto-13,14-dihydro-prostaglandin E1) and nitric oxide (NO) on platelet aggregation.

A synergistic antiplatelet effect between prostaglandins (PG), cAMP-stimulators and nitric oxide (NO), a cGMP-stimulator, has already been described. Data on a synergism between NO and the metabolites of PGE1, however, are lacking so far. We therefore tested the antiplatelet activity of the metabolites of PGE1 alone and their synergism with NO on human platelets of 8 healthy volunteers in vitro. 13,14-DH-PGE1 (ID 50 = 10.8 ng/ml platelet rich plasma (PRP)) was the only PGE1 metabolite inhibiting the ADP-induced platelet aggregation, its efficacy being 76.4% of the parent compound PGE1 (ID 50 = 8.25 ng/ml PRP). NO (ID 50 = 0.52 microM) also inhibited platelet aggregation. The combined addition of 13,14-dihydro-prostaglandin E1 (13,14-DH-PGE1) and NO caused an additive effect. The other PGE1-metabolites tested, 15-keto prostaglandin (15-K-PGE1) (ID 50 = 16.2. micrograms/ml PRP) and 15-keto-13,14-dihydro-prostaglandin(15-K-13,14-DH-PGE1) (ID 50 = 14.8 micrograms/ml PRP), neither had any relevant antiaggregatory capacity themselves nor a synergistic effect with NO. These findings could be of clinical relevance as a NO-synergism may occur not only with therapeutically administered PGE1 but also with its biologically active metabolite 13,14-DH-PGE1.

Adult↗
PubMed1992

Definition and estimation of lifetime detriment from radiation exposures: principles and methods.

Although the lifetable methodology is a standard tool in epidemiology and risk assessment, there are a number of differences in the way it has been applied by various advisory committees that have attempted to estimate radiation risks. The most fundamental of these differences concerns the choice of parameter to be estimated: the "excess lifetime risk" is the difference in lifetime risks between exposed and unexposed populations; the "risk of exposure-induced death" is the lifetime risk of dying of a disease attributable to exposure. These two quantities are not the same, even at low doses. Although both quantities have some utility in risk assessment, the "risk of exposure-induced death" comes closer to capturing the total impact of exposure. Other differences between reported risk estimates include details of the calculations, the baseline rates and age distributions of the exposed population, the forms of the models for excess rates, handling of organ-specific doses, and the groupings of cancer sites. These issues are discussed theoretically and illustrated with comparisons of the BEIR V and UNSCEAR reports. Although the risk estimates from these two reports are similar for most cancer sites, it is shown that this happens to be the result of an approximate cancellation of a number of differences that could be quite large.

Environmental Exposure↗
PubMed1992

Longitudinal variability of skin prick test results.

The skin prick test (SPT) is a commonly used procedure for assessing a specific sensitization. The longitudinal variability of test results is of interest for clinical as well as epidemiological investigations. The sensitization to four common aeroallergens (grass pollen, birch pollen, Dermatophagoides pteronyssinus, cat dander) is investigated within the framework of three consecutive SPTs at 11-month intervals for a population of 587 schoolchildren. The prevalence of sensitization based on a weal diameter of at least 2 mm was between 12.9% (cat dander) and 23.9% (grass pollen) in the initial testing. The positive predictive values of the initial SPT were between 75.3% (birch pollen) and 88.2% (cat dander) for the two subsequent SPTs. In the case of initially negative tests with positive second and third SPTs the incidence ranged between 3.2% (cat dander) and 4.3% (birch pollen) per year. A clear increase in the intensity of reaction in subsequent tests was observed in a number of probands testing positively in the initial SPT. In conclusion, our data indicate a high long-term stability of a specific sensitization to aeroallergens in SPT.

Adolescent↗
PubMed1992

Variations in asthma hospitalizations and deaths in New York City.

BACKGROUND: Recent reports have identified New York City as having asthma mortality rates that are substantially higher than expected based on US rates. This study investigates the problems of asthma morbidity and mortality in New York City. METHODS: Data on asthma hospitalizations (1982 to 1986) and deaths (1982 to 1987) among persons aged 0 to 34 years were studied. Descriptive and multivariate techniques were used to examine differences in rates among subgroups and across geographic areas. RESULTS: The average annual hospitalization rate was 39.2 per 10,000; the mortality rate was 1.2 per 100,000. Hospitalization and death rates among Blacks and Hispanics were 3 to 5.5 times those of Whites. Large geographic variations in hospitalizations and mortality occurred. Asthma hospitalization and mortality rates were highly correlated (r = .67), with the highest rates concentrated in the city's poorest neighborhoods. Household income, percentage of population Black, and percentage of population Hispanic were significant predictors of area hospitalization rates (adjusted R2 = .75). CONCLUSION: These findings provide a basis for focusing investigations of the causes of variations in asthma outcomes and targeting interventions to reduce the disproportionate morbidity and mortality borne by poor and minority populations.

Abstracting and Indexing↗
PubMed1992

[Risk factors of atherosclerosis--primary examination of Vienna employees].

In the course of an atherosclerosis intervention study, a basic medical check-up of 2105 out of 4800 employees of a Viennese banking house was carried out (37.1 +/- 11.0 years, 54.6% females). Apart from liver and kidney function parameters, an extensive lipid status was determined, the blood pressure was measured, and a cardiovascular-centered case history ascertained. The mean cholesterol level in females was 208.3 +/- 54 mg/dl and that in males was 226.8 +/- 61.1 mg/dl. The HDL-cholesterol level in males was 43.8 +/- 11.9 mg/dl; that in females (54.9 +/- 13.4 mg/dl) was significantly higher. The mean value of LDL-cholesterol in the entire group was 141.6 +/- 51.4 mg/dl and it was significantly higher in males, as well as in participants with known hypertension. 33.4% of the persons stated that they smoked. The obtained data will serve not only to discover potential interrelations between the individual risk factors of atherosclerosis in Austria, but also in particular as a basis for interventional strategies on the part of the company's medical services.

Adolescent↗
PubMed1991

Interaction between prostaglandin E1 and nitric oxide (NO).

A synergistic antiplatelet effect between prostaglandin I2 (PGI2), a cAMP-stimulator, and nitric oxide (NO), a cGMP-stimulator, has been described. Data on a PGE1-NO interaction, however, are lacking so far. We therefore examined the question in healthy volunteers, whether a similar synergism exist between PGE1 and NO on human platelets in vitro. Each of the substances alone caused a dose-dependent inhibition of ADP-induced platelet aggregation, PGE1 (1ng/mlPRP) reduced platelet aggregation by 27.8 +/- 14.6%, NO (0.3%) by 26.7 +/- 25.5%. The combination of these compounds caused an additive effect resulting in a reduction of 40.6 +/- 23.5%. The findings indicate that PGE1 (like PGI2) and NO have a synergistic antiplatelet action. The concomitant treatment with both compounds offers an interesting concept for clinical therapy.

Adult↗
PubMed1991

[Air pollutant burden and bronchial asthma in school children].

To examine the possibility of an effect of indoor and outdoor exposures on the prevalence of asthma in childhood we conducted a cross-sectional study in the area of Freiburg city and two communities in the Black Forest. The study group consists of 704 children aged 7 to 16 years. The children and their mothers took part in a standardized interview and a medical examination. Indoor exposures were assessed from information gathered in the interview by two different indices: (a) heating system and single room heating, and (b) the amount of indoor ventilation. The measurement of outdoor pollutants took into account weekly estimations of NO2 and combustion particles. The presence of asthma was recorded according to a previous medical diagnosis. Confounders were assessed during the interview (passive smoking, genetic predisposition to asthma etc.) or during the medical examination (cutaneous sensitization with a skin prick test). For the analysis of the data we applied logistic regression models and estimated odds-ratios. Only one of the four hypothesis variables displays a significant effect on the prevalence of asthma: Stoves as heating device carry a 4.8-fold relative risk for asthma compared to other types of heating. Among the confounding variables controlled for in the explanatory model, cutaneous reactions showed a relative risk of eight.

Adolescent↗
PubMed1991

Intravenous prostacyclin (PGI2) infusion to 108 patients with ischaemic peripheral vascular disease: phase II-open study.

We recently reported the results of a double-blind trial of PGI2 in 108 patients with ischaemic peripheral vascular disease Stage II according to Fontaine. They were randomly allocated to receive an intravenous infusion of either PGI2 (6 ng/kg/min over 8 hours daily for 5 consecutive days) or placebo and classified as treatment responders or non-responders on the basis of changes in absolute and relative walking times. Patients treated with placebo and those who did not improve in this double blind trial entered an open trial in which they all received infusion of PGI2 (6 ng/kg/min over 8 hours daily for 5 consecutive days). The results of this open trial are reported here. Patients who had been allocated to PGI2 in the blind trial had significantly (p less than 0.01) longer walking times as compared to placebo-treated patients prior to receiving the second (PGI2) infusion. PGI2-infusion caused significant (p less than 0.01) prolongation of walking times in both groups up to the 2nd follow-up month. One month after infusion 52% (23 patients) of the initially placebo-treated patients and 31% (14 patients) of the initially PGI2-treated patients were scored as positive treatment responders (p less than 0.01).

Aged↗
PubMed1991

[Risk factors of atherosclerosis: results of screening in Southern Austria].

In the western industrialized countries atherosclerosis is the leading cause of death. In this investigation serum cholesterol and blood pressure were measured in 4321 (60.9% females) inhabitants of Lower Austria. In addition, a short cardiovascular history was taken and age, sex, body weight, height and smoking habits were recorded. In the various villages the mean serum cholesterol differed considerably (194 +/- 52-244 +/- 49 mg/dl). Overall, women had a slightly, but non-significantly, higher serum cholesterol (224.0 +/- 53.5 mg/dl) than men (218.6 +/- 58.4 mg/dl). Although 2/3 of the participants showed an elevated serum cholesterol, only 6% were taking lipid lowering drugs. An age-dependent increase in cholesterol was found in women, whereas this correlation was present in men only until the age of 40. Approximately 30% of the participants reported a positive family history. A comparison with the mortality register showed a correlation between smoking and bronchogenic cancer. No correlation, however, was demonstrable between smoking and cardiovascular mortality--perhaps due to methodological difficulties. Regional analysis of the results indicates the importance of the role of local general practitioners in the prevention of atherosclerosis.

Adult↗
PubMed1990

[Atherosclerosis Risk Factors Intervention Study Strass (ARIS)].

Mortality due to cardiovascular disease in Austria amounted to 53.7% of the overall mortality in 1986. Elevated cholesterol, cigarette smoking and hypertension are the main risk factors. In order to estimate the prevalence of these risk factors and to evaluate the effectiveness of intervention strategies, we started the ARIS (in Strass, Lower Austria) in 1987/88. 568 participants (56.7% female, 43.3% male) were asked some questions concerning their cardiovascular status; blood pressure and 22 laboratory parameters were measured (including the serum lipid profile). Doppler sonography of the carotid arteries was performed in participants older than 60 years of age (n = 229). The mean values were: cholesterol: 220.3 +/- 45 mg/dl, systolic blood pressure: 147 +/- 45 mmHg, diastolic blood pressure: 88 +/- 29 mmHg. The percentage of smokers was 18.7%. A positive family history of coronary heart disease was reported by 32.7%. Stenosis (greater than 50%) of the carotid artery was discovered in 7 cases. After this initial examination we started an information campaign at regular two-monthly intervals with around 100 participants a time. As a first result a changed consumer behaviour was observed with respect to foods. The effectiveness of the intervention trial will be seen on evaluation of annual follow-up examinations over a 10-year period in the first place.

Adolescent↗
PubMed1990

Immunohistochemical identification of CA125 and the F(ab')2 fragments of the murine monoclonal antibody OC125 in ovarian cancer tissue.

Benign and malignant tissue samples of 19 ovarian cancer patients who received an intravenous infusion of radiolabelled F(ab')2 fragments of OC125 were examined for expression of CA125 and the cellular location of the injected antibodies. CA125 could be detected by immunohistochemistry in 47 of 71 biopsies containing cancer cells, but not in 258 biopsies with benign tissue. F(ab')2 fragments were found in 34 of these 47 biopsies. The diffuse intracytoplasmic staining pattern seemed to indicate that the injected antibodies had crossed the membranes of the cancer cells. Since the antibody could not be detected in benign tissues, further applications of OC125 for diagnostic and therapeutic purposes seems to be justified.

Antibodies, Monoclonal↗
PubMed1990

[Risk factors of atherosclerosis and awareness of risk in employees of a Viennese insurance company].

In Austria still more than 50% of overall mortality are due to cardiovascular diseases. An efficient prevention via change of life-style has been proven. We started with an intervention-trial in a Viennese insurance company. 667 persons (50.7% m, 49.1% f, 0.1% no declaration) participated in the basic examination. The mean cholesterol level was 221.85 +/- 43.87 mg/dl, being clearly above the threshold value of 200 mg/dl. In spite of the fact, that 69.7% of the female and 65.5% of the male had elevated serum cholesterol only 1.8% already took lipid lowering drugs. Participants with a positive family history (myocardial infarction) had significantly elevated cholesterol (228.2 +/- 49.4 mg/dl vs 219.7 +/- 50.4 mg/dl). Another point we were drawing special attention to was the knowledge of the participants about the risk factors of atherosclerosis. Only 13% of the males and 13.8% of the females knew their cholesterol level. 11.5% of the males and 15.9% of the females were aware of the threshold value of cholesterol. Intervention strategies (information campaign, works kitchen) have been initiated. A possible beneficial effect will be examined in biannual follow-up examinations.

Adult↗
PubMed1989

[Prostaglandin interaction in the human liver].

The binding of prostaglandin (PG) E1 and Iloprost, a chemically stable PGI2-analogue, to purified plasma cell membranes (LPZM) from liver tissue samples obtained at surgery revealed heterogeneity of the binding sites identifying high and low affinity subpopulations. In contrast to these findings only high affinity binding sites were characterized for PGE2. Displacement studies exhibited the highest competition for the PGE1-sites by PGE1 and subsequently by PGE2, Iloprost, PGD2 and PGF2 alpha. The binding of PGE2 to the hepatic receptor could be best displaced by PGE2 and subsequently by PGE1 and Iloprost, PGD2 and PGF2 alpha. In addition, PGE1, PGE2 and Iloprost enhanced cAMP-production dose-dependently over baseline. Clinical studies revealed a remarkably lower binding capacity for PGE1 in hepatocellular cancer tissue than in normal liver parenchyma. The different binding behaviour of PGE1 (Iloprost) and PGE2 for the first time provides evidence that PGE1 and PGI2 like at platelet membranes occupate the same receptor also at human LPZM. Since a reasonable number of binding sites for these substances and an enhanced cAMP-production were shown in the liver, the study indicates a regulatory role of PGs in hepatic function.

Alprostadil↗
PubMed1989

[Cholesterol screening in a bank for the detection of a risk population].

In October 1987 voluntary screening for cholesterol war performed in a bank. After preceding information had been issued to the participants 25 ml blood were drawn on 4 days from 667 employees (48.9% males, 51.1% females) for determination of the blood lipids and other parameters. The mean age (range 19 to 60) was 39 +/- 9 years; 29.2% were smokers. The mean cholesterol level amounted to 212 mg/dl. According to age- and sex-related normal values 42% exhibited an increased risk, whereby the percentage was particularly high (55%) in the age group under 30 years.

Adult↗
PubMed1989

Isradipine: a potent calcium blocker with beneficial effects on platelet function and vascular prostacyclin production.

Calcium blockers inhibit platelet aggregation induced in vitro by various stimuli, such as ADP and collagen. In this study the in vitro effects of isradipine, a new dihydropyridine-derivative, and of nifedipine on platelet aggregation and malondialdehyde-production were tested. The lowest concentrations affecting ADP-induced platelet aggregation were 1.0 micrograms/ml isradipine and 12.5 micrograms/ml nifedipine. Both drugs exhibited an inhibitory action on malondialdehyde-production in concentrations 2 to 3 times lower than those affecting platelet aggregation. In vitro, PGI2-formation by rat aortic rings incubated with calcium blockers was increased in a dose-dependent manner. The lowest concentration of isradipine which increased PGI2-generation amounted 0.5 micrograms/ml. The corresponding value for nifedipine was 10 micrograms/ml. The findings demonstrate isradipine to be more potent than nifedipine in affecting in vitro platelet aggregation and enhancing PGI2-formation.

Adenosine Diphosphate↗