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Biomedical subjects

U Baumann

Publications and source records attributed to U Baumann.

137 records · Page 8Linked to original sources

Asymmetric structure of five and six membered DNA hairpin loops.

The tertiary structure of nucleic acid hairpins was elucidated by means of the accessibility of the single-strand-specific nuclease from mung bean. This molecular probe has proven especially useful in determining details of the structural arrangement of the nucleotides within a loop. In this study 3'-labeling is introduced to complement previously used 5'-labeling in order to assess and to exclude possible artifacts of the method. Both labeling procedures result in mutually consistent cleavage patterns. Therefore, methodological artifacts can be excluded and the potential of the nuclease as structural probe is increased. DNA hairpins with five and six membered loops reveal an asymmetric loop structure with a sharp bend of the phosphate-ribose backbone between the second and third nucleotide on the 3'-side of a loop. These hairpin structures differ from smaller loops with 3 or 4 members, which reveal this type of bend between the first and second 3' nucleotide, and resemble with respect to the asymmetry anticodon loops of tRNA.

Base Sequence↗

Buccal adherence of Pseudomonas aeruginosa in patients with cystic fibrosis under long-term therapy with azithromycin.

BACKGROUND: The oropharyngeal barrier is an innate host defence mechanism to prevent bacterial Lung infection. A compromised barrier function is observed in patients with cystic fibrosis (CF) who are chronically infected with Pseudomonas aeruginosa. Macrolides are assumed to modify host defence. We investigated the oropharyngeaL barrier function in CF patients treated with azithromycin (AZM). PATIENTS AND METHODS: In a prospective study, eleven chronically infected children with CF were treated with longterm low-dose AZM. The oropharyngeal barrier function was assessed by adherence of P. aeruginosa (strain PACF 12-1) to buccal epithelial cells of the patients before and after therapy. RESULTS: The mean (standard deviation, SD) buccaL adherence before therapy was markedly high with 8.0 (4.8) bacteria/cell. Following therapy with AZM adherence decreased in all patients by 70% or 5.6 to 2.4 (1.1) bacteria/cell (p = 0.007), representing close to normal LeveLs (1.2 +/- 0.6). CONCLUSION: Long-term low-dose AZM therapy may improve the compromised oropharyngeaL barrier function in patients with CF, opening new perspectives for early treatment of P. aeruginosa infection in CF.

Adolescent↗

Is serum gentamicin level a good predictor of graft injury in intestinal transplantation?

INTRODUCTION: Following intestinal transplant (SBT), the early diagnosis and treatment of rejection is a major management aim. The diagnosis of rejection is based on histology of stomal biopsies. Oral gentamycin (2.5 mg/kg) was used for selective decontamination of the digestive system. Our hypothesis was that gentamycin might be absorbed in the presence of graft dysfunction. AIM: Our goal was to assess the correlation between serum gentamycin level and the health of the intestinal graft. SUBJECTS AND METHODS: Among 33 SBT performed from 1993 to 2005, serum gentamycin levels were performed once weekly or more often when there was a suspicion of rejection. All data were analyzed retrospectively. RESULTS: Adequate trough levels were achieved for only 23 patients, six of whom had histologically proven rejection and only one did not have a raised gentamycin content. Five patients with raised levels but no rejection included two with severe intestinal ischemia and three with bowel obstruction/ileus. Four of the five patients required laparotomies. CONCLUSION: We concluded that in our study raised serum gentamycin levels were a good predictor of rejection or significant injury to the graft.

Biomarkers↗

[Lectin-reactive alpha-fetoprotein in tyrosinaemia type I].

UNLABELLED: Despite the introduction of NTBC into the treatment of tyrosinaemia type I (TT1) and a considerable improvement in the outcome of these patients, the principal risk of developing hepatocellular carcinoma (HCC) in this metabolic disorder remains mainly in those children with late introduction of NBTC after the second year of life. Serial total alpha-Fetoprotein (AFP) levels are used to evaluate the individual risk to develop malignant changes. A failure of AFP to decrease on adaequate treatment or a secondary increase after a period of falling levels have been an indication for liver transplantation. Lectin-reactive alpha-Fetoprotein is a recently described marker to distinguish hepatocellular carcinoma from benign liver disease in adult cirrhotic patients. AIMS: To investigate if the analysis for Lectin-reactive alpha-Fetoprotein would lead to earlier detection of HCC compared to a judgement based on the evolution of standard total AFP alone. PATIENTS: We report the analysis of 12 patients with TTI and histologically proven HCC. There of 5 were diagnosed under one year of age, but NTBC treatment was started between 2 years 3 month and 7 years of age except in one case in which NTBC was introduced when the diagnosis of TTI was made. The remainder of the patients cover up to the age of 15 years. All patients had been treated with NTBC. METHODS: Lectin containing agarose gel for AFP electrophoresis leads to AFP separation according to different affinities of the varying carbohydrate chains of AFP to lectins. RESULTS: AFP subfractions could be identified in all 12 patients. In 6 patients the L3-AFP rose before the total AFP. In 3 patients the rise in L3-AFP was consistent with the rise of the total AFP and in 3 patients the L3-AFP was raised after the total AFP or did not increase at all. DISCUSSION: We were able to identify 6 out of 12 patients who had an early increase of L3-AFP before they developed a change in total AFP levels. The clinical significance of these early changes need to be determined. Lectin-affinity electrophoresis may have a potential role as an additional tool that may help to discriminate benign liver disease from HCC in TTI. CONCLUSIONS: We suggest the further evaluation of lectin-reactive AFP in TTI.

Adolescent↗

Comparison of the TEMPO+ ear-level speech processor and the cis pro+ body-worn processor in adult MED-EL cochlear implant users.

A study was conducted to compare the new MED-EL TEMPO+ ear-level speech processor with the CIS PRO+ body-worn processor in the COMBI 40/COMBI 40+ implant system. Speech tests were performed in 46 experienced subjects in two test sessions approximately 4 weeks apart. Subjects were switched over from the CIS PRO+ to the TEMPO+ in the first session and used only the TEMPO+ in the time between the two sessions. Speech tests included monosyllabic word tests and sentence tests via the telephone. An adaptive noise method was used to adjust each subject's scores to approximately 50%. Additionally, subjects had to complete a questionnaire based on their 4 weeks of experience with the TEMPO+. The speech test results showed a statistically significant improvement in the monosyllabic word scores with the TEMPO+. In addition, in the second session, subjects showed a significant improvement when using the telephone with the TEMPO+, indicating some learning in this task. In the questionnaire, the vast majority of subjects found that the TEMPO+ allows equal or better speech understanding and rated the sound quality of the TEMPO+ higher. All these objective and subjective results indicate the superiority of the TEMPO+ and are mainly attributed to a new coding strategy called CIS+ and its implementation in the TEMPO+. In other words, based on the results of this study, it appears that after switching over from the CIS PRO+ to the TEMPO+, subjects are able to maintain or even improve their own speech understanding capability.

Adult↗