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Biomedical subjects

S Bent

Publications and source records attributed to S Bent.

18 recordsLinked to original sources
PubMed2000

[Decontamination of highly polychlorinated biphenyl contaminated indoor areas by complete removal of primary and secondary sources].

A new sanitization concept in a school highly contaminated with polychlorinated biphenyls (PCBs) is described. The maximum indoor air concentration was 13,100 ng/m3 PCB. Initially the average indoor PCB concentrations attained 6,000-7,000 ng/m3. A reduction to 226 +/- 89.1 ng/m3 (n = 24) was achieved. Ten months later the PCB concentration was 171 +/- 57.6 ng/m3 (n = 3). Primary sources were PCB-contaminated elastic sealants and the paint of radiators or heating elements. Also PCB-contaminated materials were walls, floors and ceilings. These secondary contaminations were also relevant for PCB indoor air concentrations. The primary sources were removed dust-free by manual procedures. Contrary to other sanitization concepts all secondary-contaminated PCB materials were also removed with a high-pressure water method specially developed for such cases. Because of the removal of all relevant primary and secondary PCB deposits, a lasting effect can be expected. By this sanitization concept, the use of new and less intensively explored products suppressing the diffusion of PCBs into the indoor air and whose toxicity is hardly known, may be prevented, thus avoiding the need for prolonged control measurements. Before using the above-mentioned new sanitization concept, another concept had been rejected for lack of efficiency, thus avoiding unnecessary costs. The companies performing sanitization should be compelled to accept a defined lowest PCB concentration.

Adult↗
PubMed1999

Antibiotics in acute bronchitis: a meta-analysis.

PURPOSE: Most patients with acute bronchitis who seek medical care are treated with antibiotics, although the effectiveness of this intervention is uncertain. We performed a meta-analysis of randomized, controlled trials to estimate the effectiveness of antibiotics in the treatment of acute bronchitis. SUBJECTS AND METHODS: English-language studies published January 1966 to April 1998 were retrieved using MEDLINE, bibliographies, and consultation with experts. Only randomized trials that enrolled otherwise healthy patients with a diagnosis of acute bronchitis, used an antibiotic in the treatment group and a placebo in the control group, and provided sufficient data to calculate an effect size were included. RESULTS: We identified eight randomized controlled trials that satisfied all inclusion criteria. These studies used one of three antibiotics (erythromycin, doxycycline, trimethoprim/sulfamethoxazole). The use of antibiotics decreased the duration of cough and sputum production by approximately one-half day (summary effect size 0.21; 95% CI, 0.05 to 0.36). For specific symptoms, there were nonsignificant trends favoring the use of antibiotics: a decrease of 0.4 days of purulent sputum (95% CI, -0.1 to 0.8), a decrease of 0.5 days of cough (95% CI, -0.1 to 1.1), and a decrease of 0.3 days lost from work (95% CI, -0.6 to 1.1). CONCLUSION: This meta-analysis suggests a small benefit from the use of the antibiotics erythromycin, doxycycline, or trimethoprim/sulfamethoxazole in the treatment of acute bronchitis in otherwise healthy patients. As this small benefit must be weighed against the risk of side effects and the societal cost of increasing antibiotic resistance, we believe that the use of antibiotics is not justified in these patients.

Acute Disease↗
PubMed1996

[Solvent emissions in a school building after using a construction moisture protection substance].

A wall of a school building was treated with a moisture repellent containing a silicone resin and white spirit. In the temporal connection with this a child experienced an exacerbation of its bronchial asthma. Some weeks after the second application the users of the rooms complained about unpleasant odor and discomfort. As shown by analysis the white spirit containing aliphatic and aromatic hydrocarbons diffused through the 50 cm thick stone wall into the classrooms. Due to the considerable concentration of the pollutant a part of the building could not be used any longer. In Germany no guideline values exist for white spirit or any mixtures of hydrocarbons in indoor air for non-occupational workplaces. For the reopening of the rooms a target value of 300 micrograms VOC/m3 was set. The incident shows that building materials can cause health problems and discomfort even if instructions of application are followed.

Air Pollution, Indoor↗
PubMed1995

[Copper-induced liver cirrhosis in a 13-month old boy].

A micronodular liver cirrhosis with a massive accumulation of copper in hepatocytes was found in a 13-months old boy. The causal factor was due to the increased copper concentration within the drinking water, which caused liver disease of the boy who had been completely weaned at the age of four weeks. The cooper concentration found in the drinking water exceeded 12 mg/l after a twelve hour stagnation time; after several days of stagnation the highest measured concentration was 28.6 mg/l. This increase is caused by the combined effect of copper pipes and acidulous well water.

Biopsy↗
PubMed1994

[Management of indoor air pollution by polychlorinated biphenyl compounds exemplified by two Hagen schools].

An indoor pollution of polychlorinated biphenyls (PCB) of about 4000 ng/m3 could be reduced by an average amount of 68% by temporary sealing of the primary source in combination with intensive cleaning. The costs were around DM 100,000.- for the school building containing 12 classrooms. Due to this procedure a continued usage of the building is possible until a concept of decontamination is available. In another building the PCB indoor pollution was reduced by 73% in a representative trial restoration, whereas the stripping of the paint with a chemical caustic substance induced a significant reduction of the PCB concentration. The usage of special air conditioners--called "Luftwäscher"--in the classrooms did not reduce the PCB concentration. The realisation of disturbing factors such as the fluctuation of the temperature is of great importance for judging the efficiency of decontamination procedures. The possible misinterpretation regarding the results and the data of decontamination procedures can be excluded by parallel measurements in control rooms. Costs induced by these additional analyses will be reduced by the early realization of ineffective steps.

Adolescent↗
PubMed1991

The influence of H1-, H2- and H3-receptors on the spontaneous and ConA induced histamine release from human adenoidal mast cells.

The effects of the H3-agonist R-alpha-methylhistamine (R-alpha-MeHA) and the H3-antagonist thioperamide on the spontaneous and concanavalin A (ConA) induced histamine release from human mast cells were tested and compared with the effect of some H1- and H2-receptor active substances. R-alpha-MeHA (10(-9)-10(-7) M) exerted no effect on histamine release whereas thioperamide increased the spontaneous release at 10(-6)-10(-4) M but inhibited the ConA induced release in a narrow concentration range (10(-6)-10(-5) M). This enhancement might be taken as an indication of the existence of H3-receptor dependent autoregulation although presently other mechanism cannot be excluded.

Adenoids↗
PubMed1991

Comparison of dermal and systemic application of glucocorticoids on the RM 3/1+ macrophage in human blood.

Dermal administration of either hydrocortisone or fluprednidene to healthy skin causes only a weak and short-lasting increase of the proportion of the anti-inflammatory macrophage RM 3/1 in the blood compared to the effect of the systemic application of glucocorticoids on this cell subtype. On the other hand, a rather permanent increase of these macrophages could be observed in untreated patients suffering from certain skin diseases, e.g. urticaria, atopic dermatitis, psoriasis.

Administration, Cutaneous↗
PubMed1990

Effects of calmodulin antagonists on human adenoidal mast cells.

N-(6-aminohexyl)-1-naphthalenesulfonamide (W5), N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W7) and Triflupromazine (TFPr) are substances with calmodulin antagonistic properties. All of these compounds inhibited the Con A-induced histamine release from human adenoidal mast cells. Maximal inhibition for W5 was observed at 200 microM, for W7 at 50 microM and for TFPr at 20 microM. Higher concentrations of each substance induced a marked histamine release. The kinetics of the mediator release were found to be different for Con A and W7 only after 5 mins incubation. The kinetics of TFPr were found to be biphasic: a slow onset was followed by a fast release reaction.

Adenoids↗
PubMed1990

Glucocorticoid-induced appearance of the macrophage subtype RM 3/1 in peripheral blood of man.

The effect of intravenous administration of the glucocorticoid prednylidene on the macrophage subtype RM 3/1 in the peripheral blood of man was studied. Injection of 60 mg steroid resulted in an increase in the proportion of RM 3/1 positive monocytes 12 h after application from the basic level to about 80%. After 24 h the number of RM 3/1 positive cells decreased but remained elevated over the basis rate for a period of at least 15 days. Similar results were obtained after administration of 30 or 6 mg prednylidene even if the peak value occurred with a delay of 12 h after 6 mg. A dose- and time-dependent induction of the RM 3/1 positive subtype could also be demonstrated in vitro by the addition of prednylidene or dexamethasone to cultured purified human monocytes/macrophages. Deoxycortone or indomethacin had no effects. These results suggest that glucocorticoids exert their influence on cells of the mononuclear phagocytic lineage by inducing a distinct monocyte/macrophage subpopulation which seems to be associated with anti-inflammatory functions.

Adult↗
PubMed1986

Evaluation of acute bioassays for assessing toxicity of polychlorinated biphenyl-contaminated soils.

Proposed State of California regulations use fish toxicity information as one criterion in municipal or industrial waste hazard evaluation. Static 96-hr bioassays were performed using fathead minnows (Pimephales promelas), blacksmith (Chromis punctipinnis), and glass shrimp (Palaemonetes kadiakensis) exposed to soil experimentally contaminated with up to 500 ppm polychlorinated biphenyl (PCB) capacitor fluid added at a concentration of 500 mg liter-1. Other bioassays were conducted with a 6-day mixing period prior to the bioassay or with acetone added to solubilize the PCBs. No mortality attributable to PCB toxicity was observed in definitive bioassays using the two fish and one invertebrate species. PCB levels leached from soil containing 500 ppm Aroclor 1242 ranged from less than 0.6 to 3.4 ppb in freshwater tests to 3.5 ppb in seawater bioassays. Using these data as the basis for waste classification, soils contaminated with up to 500 ppb PCBs during capacitor spills would be designated nonhazardous. PCBs are known to be environmentally persistent and to bioaccumulate. Acute toxicity tests, therefore, do not adequately evaluate the general toxicity of PCB-contaminated soils. Hazardous waste regulations for hydrophobic compounds such as PCBs should instead be based upon chronic toxicity data and should also consider bioaccumulation potential.

Animals↗
PubMedDate not supplied

Antibiotics in chronic obstructive pulmonary disease exacerbations. A meta-analysis.

OBJECTIVE: A meta-analysis of randomized trials was performed to estimate the effectiveness of antibiotics in treating exacerbations of chronic obstructive pulmonary disease (COPD). DATA SOURCES: English-language studies published from 1955 through 1994 were retrieved using MEDLINE, Index Medicus, bibliographies, and consultation with experts. MEDLINE search terms included "COPD," "chronic bronchitis," and "antibiotic(s)." STUDY SELECTION: Only randomized trials that enrolled patients having an exacerbation of COPD, used an antibiotic in the treatment group and placebo in the control group, and provided sufficient data to calculate an effect size were included in the meta-analysis. DATA EXTRACTION: Descriptive and outcome data from each study were independently in the meta-analysis. DATA SYNTHESIS: Overall summary effect size of the nine trials satisfying all inclusion criteria was 0.22 (95% confidence interval [CI], 0.10 to 0.34), indicating a small benefit in the antibiotic-treated group. Similar analysis of the six studies that provided data on peak expiratory flow rate changes revealed a summary effect size of 0.19 (95% CI, 0.03 to 0.35) and a summary change in peak expiratory flow rate of 10.75 L/min (95% CI, 4.96 to 16.54 L/min) in favor of the antibiotic-treated group. Sensitivity analyses did not significantly affect these results. CONCLUSIONS: These analyses suggest a small but statistically significant improvement due to antibiotic therapy in patients with exacerbations of COPD. This antibiotic-associated improvement may be clinically significant, especially in patients with low baseline flow rates.

Anti-Bacterial Agents↗
PubMedDate not supplied

Sickle cell disease.

Explore the source record for details and available documents.

Anemia, Sickle Cell↗