Evidence for a new pathway in the bacterial degradation of 4-fluorobenzoate.
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Six bacterial strains able to use 4-fluorobenzoic acid as their sole source of carbon and energy were isolated by selective enrichment from various water and soil samples from the Stuttgart area. According to their responses in biochemical and morphological tests, the organisms were assigned to the genera Alcaligenes, Pseudomonas, and Aureobacterium. To elucidate the degradation pathway of 4-fluorobenzoate, metabolic intermediates were identified. Five gram-negative isolates degraded this substrate via 4-fluorocatechol, as described in previous studies. In growth experiments, these strains excreted 50 to 90% of the fluoride from fluorobenzoate. Alcaligenes sp. strains RHO21 and RHO22 used all three isomers of monofluorobenzoate. Alcaligenes sp. strain RHO22 also grew on 4-chlorobenzoate. Aureobacterium sp. strain RHO25 transiently excreted 4-hydroxybenzoate into the culture medium during growth on 4-fluorobenzoate, and stoichiometric amounts of fluoride were released. In cell extracts from this strain, the enzymes for the conversion of 4-fluorobenzoate, 4-hydroxybenzoate, and 3,4-dihydroxybenzoate could be detected. All these enzymes were inducible by 4-fluorobenzoate. These data suggest a new pathway for the degradation of 4-fluorobenzoate by Aureobacterium sp. strain RHO25 via 4-hydroxybenzoate and 3,4-dihydroxybenzoate. (+info)
View of the regulatory use of rat liver foci data in the Federal Republic of Germany.
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Altered hepatocellular foci (AHF) are suspected of being phenotypic markers of a stage in the sequential process of tumor development in the liver. A number of short-term and mid-term tests, including some that use AHF as an endpoint, have been reviewed by the Federal Health Office to determine if they are suitable to replace long-term animal experiments for predicting the carcinogenic potential of chemicals. Although regulatory authorities recognize the advantages of short-term tests, including a possible reduction in the number of animals used, it is still premature to make a general recommendation regarding the suitability of these tests for regulatory decision-making. At this time, the Commission of European Communities (CEC) follows a decision-tree approach for regulating chemicals coming to the market. Since it is unrealistic to expect a reasonable number of AHF to evaluate in 28-day or 90-day studies, AHF can only be practically evaluated in the conventional long-term bioassay. There is still insufficient knowledge regarding the biological significance of the various phenotypic forms of AHF to use them as a relevant endpoint for regulatory purposes. However, data on AHF derived from routine hematoxylin and eosin (H&E) work can be used to aid in the interpretation of the study and in recommending additional investigations. (+info)
Unsatisfactory specificities and sensitivities of six enzyme immunoassays for antibodies to hepatitis B core antigen.
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To examine the consistency and comparability of anti-hepatitis B core antigen (anti-HBcAg) assays, four blood donation centers of the Red Cross in the Federal Republic of Germany tested 4,080 unselected blood donors with six different tests in parallel. Confirmation testing of reactive samples was done in the National Reference Center for Viral Hepatitis. Depending on the test kit used, 4.1 to 9.9% of serum samples were initially positive and 2.9 to 7.5% were repeatedly positive. Sixteen percent of serum samples were positive in at least one test but only three percent were positive in all six tests. Statistical analysis of frequency distribution of optical densities for each test suggested that there should be a correction of the cutoff values. This reduced the number of false-positive results by half, but a significant proportion of discrepant results could not be resolved. The lack of specificity and consistency requires cautious interpretation of isolated anti-HBcAg results in clinical specimens. Screening of predominantly anti-HBcAg-negative populations (e.g., blood donors) by the current anti-HBcAg test kits will almost necessarily give unsatisfactory results. (+info)
CHOP-VP16 chemotherapy and involved field irradiation for high grade non-Hodgkin's lymphomas: a phase II multicentre study.
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Sixty previously untreated patients with high grade non-Hodgkin's lymphomas stages II-IV received cyclophosphamide 750 mg m2 i.v., doxorubicin 50 mg m2 i.v., and vincristine 2 mg i.v. on day 1, prednisolone 100 mg p.o. on days 1-5 and etoposide 100 mg m2 i.v. on days 3-5 (CHOP-VP16). After four courses an involved field irradiation with a total dose of 25 Gy was employed and followed by two additional courses of CHOP-VP16. The overall response rate was 93%, with 49 patients (82%) achieving a complete remission (CR). Seven patients had a partial response and four patients showed no response. During a median follow-up period of 55 months, 22 of the 49 patients with CR relapsed, seven of them achieving a second complete remission with the same drug regimen. A maintained complete remission of up to 68 months was seen in 55% of all patients initially achieving CR. The median survival is 43 months. Mean side-effects of this drug regimen were alopecia (89%), nausea/vomiting (76%) and leukopenia (61%). No therapy-related deaths were seen. The results of this study demonstrate that this combined modality treatment produces high complete remission rates and that more than half of these patients achieve long-term disease-free survival. (+info)
Disability from inflammatory bowel disease among employees in West Germany.
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The statistics of the German social security system were used to analyse the epidemiology of inflammatory bowel disease (IBD) in Germany and to assess its impact on disability. Patients granted disability pension for IBD were compared with a control group of patients disabled from other causes. Crohn's disease and ulcerative colitis led to disability in significantly younger patients than other diseases. Disability from Crohn's disease was 2.0-fold more common in women than men (95% confidence interval: 1.8-2.3), while disability from ulcerative colitis was similar in both sexes. White collar employees were affected by both diseases more frequently than blue collar employees, the ratio being 1.3 (1.2-1.5) in Crohn's disease and 1.6 (1.4-1.8) in ulcerative colitis. Although IBD is relatively rare, it has severe socioeconomic implications, because compared with other diseases, predominantly young age groups become disabled. (+info)
Risk of cancer from the use of tar bitumen in road works.
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Tar bitumens are increasingly being used as a binder in road works. They consist of a standard product of about 70% bitumen and 25-30% tar. Tar bitumens are classifiable as the pyrolysis products of organic materials and are applied hot. Depending on the temperature used there are emissions of various intensities of polycyclic aromatic hydrocarbons (PAH), some of which are carcinogenic. A total of 250 one hour air samples was taken at breathing height on 20 days at 11 road works sites. The region of road paving operations in the immediate neighbourhood of the finishing machine operator and the screedmen were the chosen sampling points. A total of 19 unsubstituted chromatography/mass spectrometry. These included benzo[b]fluoranthene, benzo[a]pyrene, chrysene, dibenzo[a,h]anthracene, and indeno[1,2,3-cd]pyrene, all of which are carcinogenic. The median concentrations of chrysene and of benzo[b,j + k] fluoranthenes (determined en masse) were 9.3 and 2.8 micrograms/m3 respectively. The median concentrations of benzo[a]pyrene (BaP) and indeno[1,2,3,-cd]pyrene were 0.7 and 0.2 micrograms/m3 respectively. Dibenzo[a,h]anthracene had the lowest median concentration with about 0.03 micrograms/m3. Of the resulting shift means, the BaP concentration was over 1 microgram/m3 in about 50% of the cases, over 2 micrograms/m3 in 35%, and over 5 micrograms/m3 in about 15%. Even when the temperature of the paving mix was only between 120 degrees and 135 degrees C. 4.8% of the concentrations (identical to 3 samples) were greater than 2 micrograms BaP/m3, this value was exceeded in 34.9% of the determinations (identical to 30 samples) when the temperature of the tar bitumen was between 135 degrees and 150 degrees C. The highest concentration measured here was 17.8 micrograms BaP/m3. The recommended maximum paving temperature of the paving mix of 150 degrees C was exceeded in about 23% of all cases. The maximum concentration determined under any condition was 22 microgram/m(3). Thus the employment of tar bitumen as a binding material during road paving operations must be regarded as causing a considerable risk to health. The primary task is to ascertain whether tar bitumen can be replaced as a binder in paving for roads and what safety measures are practicable. (+info)
The importance of listening to medical students' experiences when teaching them medical ethics.
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This paper describes the change of emphasis that occurred in the teaching of ethics to small groups of clinical students. Although the original focus of the course was on the analysis of ethical dilemmas associated with individual patients known to the students, it soon became evident that there were, for the students themselves, more fundamental ethical dilemmas in their new role as clinical students. These included worries about how to respond when patients asked questions which their consultants had previously deceived them about, worries about inflicting pain on patients, as with intravenous cannulation, and the role of the medical student in the clinical team. We emphasise the need to explore student experiences as part of the process of ethics teaching. (+info)
PGM1 system. Report on the international workshop, October 10-11, 1983, Munich, West Germany.
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Because of the increase in the number of PGM1 polymorphisms and the existence of four distinct nomenclatures for expressing subtypes by isoelectric focusing, a nomenclature workshop was held in 1983 to compare variants and arrive at a single method for reporting PGM1 data. A total of 30 rare variants were identified and the recommended method for expressing the four common alleles is PGM1*1A, PGM1*1B, PGM1*2A, and PGM1*2B. (+info)