Search PubMed⌕ Search

Biomedical subjects

W Bär

Publications and source records attributed to W Bär.

At least 19 recordsLinked to original sources
PubMed2002

Diagnosis of systemic Candida infections in patients of the intensive care unit. Significance of serum antigens and antibodies.

The combined detection of Candida antigen and antibody for the determination of systemic Candida infections (SCI) was investigated. One hundred and four patients from the intensive care unit (ICU) were analysed. Seventeen of the patients were suspected of having SCI, based on clinical and laboratory criteria. In these patients, Candida antigens and antibodies were analysed extensively. Ten patients had a positive Candida antigen (titre >1:16) determined by the latex agglutination assay Cand-Tec(R) and their median antibody titre was 1:160 in the indirect haemagglutination test (HAT). Seven antigen-negative patients had a median titre of 1:1280 (HAT). Forty-one of 42 colonized control patients had negative antigen titres and a median antibody titre of 1:160. The sensitivities and specificities were 58.8% and 97.6% for antigenemia, and 52.9% and 85.7% for antibody detection. These values reached 100.0% and 83.3%, respectively, when the results of both tests were combined. This indicates a high degree of concordance between serological results (Candida antigen and/or antibodies) and clinical presentation. We conclude, that the combined investigation of antigen and antibody titres might be a helpful tool in the characterization of SCI in ICU patients, if antigen titres are >or=1:16 or antibody titres (HAT) are >or=1:640.

Adolescent↗
PubMed2001

Contamination of bronchoscopes with Mycobacterium tuberculosis and successful sterilization by low-temperature hydrogen peroxide plasma sterilization.

BACKGROUND: The transmission of mycobacteria by bronchoscopes has been reported several times in the last years. To explore methods to prevent transmission of tuberculosis in this way, we sterilized contaminated bronchoscopes with low-temperature hydrogen peroxide gas plasma sterilization. METHODS: Bronchoscopes were contaminated with Mycobacterium tuberculosis and decontaminated with a washer/disinfector ("normal washing"). Some were additionally disinfected with glutaraldehyde ("intensive washing"). Afterward the bronchoscopes were sterilized by low-temperature hydrogen peroxide plasma sterilization. RESULTS: After normal washing, 8/17 samples had positive results by culture, and 7/17 had positive results by nucleic acid amplification technique. After intensive washing, all samples had negative results by culture, and 10/25 had positive results by nucleic acid amplification technique; after sterilization with low-temperature hydrogen peroxide plasma sterilization, all samples had negative results by culture and nucleic acid amplification technique. CONCLUSION: Washing of bronchoscopes, as performed normally, is not sufficient for decontamination of bronchoscopes. Additional disinfection is recommended. If the nucleic acid amplification technique is used for diagnostic procedures, sterilization by low-temperature hydrogen peroxide plasma sterilization is recommended to avoid false-positive results.

Anti-Infective Agents, Local↗
PubMed2001

A variable fluence step clustering and segmentation algorithm for step and shoot IMRT.

A step and shoot sequencer was developed that can be integrated into an IMRT optimization algorithm. The method uses non-uniform fluence steps and is adopted to the constraints of an MLC. It consists of a clustering, a smoothing and a segmentation routine. The performance of the algorithm is demonstrated for eight mathematical profiles of differing complexity and two optimized profiles of a clinical prostate case. The results in terms of stability, flexibility, speed and conformity fulfil the criteria for the integration into the optimization concept. The performance of the clustering routine is compared with another previously published one (Bortfeld et al 1994 Int. J. Radiat. Oncol. Biol. Ph.vs. 28 723-30) and yields slightly better results in terms of mean and maximum deviation between the optimized and the clustered protile. We discuss the specific attributes of the algorithm concerning its integration into the optimization concept.

Algorithms↗
PubMed2001

Second primary glioblastoma.

Although characterized by a highly variable phenotype and multiple genetic alterations, glioblastomas are considered monoclonal in origin. We here report on a 64-yr-old patient who developed a second glioblastoma in the left frontal lobe 10 yr after surgical resection of a glioblastoma of right frontal lobe. The first tumor contained 2 p53 mutations, in codon 213 (CGA-->TGA, Arg-->stop) and codon 306 (CGA-->TGA, Arg-->stop), further, 1 missense PTEN mutation (codon 257, TTC-->TTA, Phe-->Leu) and a silent PTEN mutation (codon 154, TTC-->TTT, Phe-->Phe). The second glioblastoma also contained multiple, but different mutations: p53 mutations in codons 158 (CGC-->CAC, Arg-->His) and 273 (CGT-->TGT, Arg-->Cys), and a PTEN mutation in codon 233 (CGA-->TGA, Arg-->Stop). Both neoplasms had a homozygous p16 deletion. The discordant pattern of mutations indicates that the second glioblastoma was not a recurrence but an independent second glioblastoma. The presence in these neoplasms of multiple mutations in tumor suppressor genes suggests the involvement of a novel disease mechanism but there was no indication of a DNA mismatch repair deficiency or of an inherited tumor syndrome.

Chromosomes, Human, Pair 10↗
PubMed2000

Bradycardia.

Explore the source record for details and available documents.

Adult↗
PubMed2000

Biostatistics for mixed stains: the case of tested relatives of a non-tested suspect.

Analysis of a mixed biological stain by means of highly polymorphic VNTR systems usually reveals a profile composed of multiple markers. If the victim and one or several suspects match the profile, the evidential strength of the matches has to be very carefully analysed. The appropriate methods for the statistical analysis of DNA profiles advanced recently were limited to cases with no relationship between the tested and non-tested persons. The present paper extends the theory beyond this limitation.

Biometry↗
PubMed1999

Biostatistical evaluation of mixed stains with contributors of different ethnic origin.

The analysis of a mixed biological stain by means of highly polymorphic VNTR systems usually reveals a profile composed of multiple alleles. If the victim and one or several suspects match the profile the evidential strength of the matches has to be very carefully analysed. The appropriate methods for the statistical analysis of DNA profiles advanced recently by Weir with coauthors and by the present authors are limited to cases where all non-tested persons involved in the analysis belong to the same ethnic group. The present paper extends the theory beyond this limitation.

Biometry↗
PubMed1999

[Species diagnosis of a tissue using the polymerase chain reaction].

The unambiguous identification of a biological specimen can deliver invaluable evidence to solve criminal cases. In this case the origin of a heart had to be clarified. Using the polymerase chain reaction technique and species-specific primer pairs for two genes it was clearly shown that this tissue was not from a human but from a pig.

Animals↗
PubMed1998

[Driving fitness/driving capacity of patients treated with methadone].

To answer the question whether or not therapeutic methadone doses significantly reduce traffic-related performance of drivers on medically supervised methadone programmes, 34 methadone substitution patients, all of them volunteers, were subjected to a test series: the focus of the study was a psychophysical test battery consisting of 10 individual performance tests to assess essential functions with regard to driving ability, such as concentration, attention, reaction capability, memory, perception and sensorimotor coordination. In evaluating the results of the psychophysical tests, multiple drug use and subjective methadone influence at the time of the examination were taken into consideration but current methadone blood level was neglected. The results were compared to those of a control group. The methadone group (n = 34) consisted of 25 men and 9 women aged between 18 and 38. At the time of the study, the majority of the test persons (29) were on low dosage methadone maintenance (up to 60 mg/day). In the urine samples of approximately 2/3 of the test persons, evidence was found for multiple drug use together with other psychotropic substances, the most frequent (14) being cannabis metabolites. Referring to their driving practices, a mere 4 out of 29 drivers had not committed any driving offences. A comparison of the psychophysical performance of the whole methadone group (n = 34) with a control group demonstrated that the methadone substitution patients achieved rather lower results in almost all variables. These performance deficits were particularly conspicuous in sustained attention, sensorimotor coordination and reaction capability. 12 "methadone only" participants, i.e. methadone probands without any additional consumption of psychotropic substances showed-partly considerably-better performance than the methadone group as a whole and also achieved normal results in relation to the test norm. Nevertheless, once again, results tended to be of lower level in comparison to the control group. "Methadone only" substitution patients, in particular those volunteers without a current subjective methadone influence-reached practically the same results as the corresponding control subjects, or at least average results based on test norm. However, the study revealed distinctive performance impairment (e.g. in sustained attention, reaction capability) when other psychotropic substances (including alcohol and cannabis!) were taken as well during the subjective methadone phase. The performance deficits were predominantly caused by a slowing down of reactions. Our study illustrates that, under certain conditions, long-term methadone maintenance under strict medical supervision does not have any significant unfavourable impact on the psychophysical performances in driving ability as examined in this study. Thus, these research findings support the previous Zurich experiences, according to which driving ability--and in the end also driving aptitude--of the methadone substitution patients does not depend on the methadone therapy itself, nor on the amount of the daily methadone intake. In making the final medical judgement on driving ability, the presence of a mixed drug use and the personality of the person in question are of far greater importance.

Accidents, Traffic↗
PubMed1998

Interpreting forensic DNA evidence on the basis of hypotheses testing.

Analysis of a mixed biological stain by means of highly polymorphic VNTR systems usually reveals a profile composed of multiple markers. If the victim and one or several suspects match the profile the evidential strength of the matches has to be very carefully analysed. It is shown that a treatment to evaluate mixed stains within the scope of a hypotheses testing approach yields a formula identical to one proposed recently by Weir und coauthors. A simple combinatorial proof of this formula is presented. Further, a special computational formula is derived for the cases where the formula of Weir turns out to be cumbersome.

DNA↗
PubMed1998

Mycobacterium ulcerans infection in a child from Angola: diagnosis by direct detection and culture.

Buruli ulcer, caused by Mycobacterium ulcerans, is a chronic ulcerative skin disease, found predominantly in central and west Africa and Australia. A boy of 2.5 years of age from Angola was admitted to our hospital with severe kwashiokor and a large ulcer with undermined edges on the left side of the thorax. Further examination revealed anaemia, hypoproteinaemia, bacterial superinfection of the ulcer and intestinal parasites. Histological analysis showed acid-fast bacilli and histopathological changes typical of Buruli ulcer. M. ulcerans was detected by PCR and culture. The patient was treated by surgical excision of diseased skin, followed by split-skin grafting. He also received antibiotic therapy (ciprofloxacin, clarithromycin, rifabutin, and dapsone). After six months, the child was discharged from hospital in good condition. This is the first published case of Buruli ulcer from Angola.

Angola↗
PubMed1998

Phenotypic and genotypic differentiation of several human and avian isolates of Cryptococcus neoformans.

The Cryptococcus neoformans strains isolated from two human cases could be diagnosed as Cr. neoformans var. neoformans by differentiation on the basis of their characteristics determined by proline, canavanine and EDTA urease tests. The results of the serovar assignment were: for the isolate from the meningoencephalitis patient with lethal outcome, serovar A; for the strain isolated from the osteomyelitis patient with benign course, serovar D. Also, the PCR fingerprinting using primers (GACA)4, (CAC)5 and FM 1 resulted in a clear and reproducible assignment of the Cr. neoformans strains to the varieties neoformans and gattii, respectively, and, in addition, it confirmed the serovar assignment. No statistically confirmed differences in virulence between the osteomyelitis and the meningoencephalitis strain could be established by i.v. testing in mice, nor did the PCR with several primers provide any clues to a genetically determined higher virulence of the meningoencephalitis strain. The different classification as serovars A and D does not allow any conclusions concerning different virulence. It was not possible to retrospectively establish the sources of infection of the two Cr. neoformans infections, but pigeon faeces may well have played a role as a reservoir for one of the illnesses.

Animals↗
PubMed1998

The central, surface-exposed region of the flagellar hook protein FlgE of Campylobacter jejuni shows hypervariability among strains.

In a previous study, we observed that monoclonal antibodies raised against the hook protein FlgE of Campylobacter jejuni LIO 36, isolate 5226, bound exclusively to this strain. The aim of this study was to elucidate the molecular basis for these binding specificities. The hook protein-encoding gene flgE of C. jejuni was cloned in Escherichia coli and sequenced. The flgE genes of four additional C. jejuni strains were amplified by PCR and also sequenced. Comparison of the deduced amino acid sequences revealed a high degree of variability in the central parts of the FlgE proteins among the strains, including variable and hypervariable domains. These findings may indicate a selective pressure of C. jejuni hosts, forcing the bacteria to generate variations in surface-exposed antigenic determinants.

Amino Acid Sequence↗