Biomedical subjects
Publications and source records attributed to C Horn.
Sequences of 3279 sequences of tRNA genes and tRNAs published up to December 1996 are included in the compilation. Alignment of the sequences, which is most compatible with the tRNA phylogeny and known three-dimensional structures of tRNA, is used. Sequences and references are available under http://www.uni-bayreuth. de/departments/biochemie/trna/
The alanine-proline antigen (APA), representing less than 2% of the released or excreted material during Mycobacterium tuberculosis or bacillus Calmette-Guérin (BCG) growth, is a dominant antigen present during M. tuberculosis infection or BCG immunization. To obtain new tools to dissect the major epitopes of the APA molecules, seven monoclonal antibodies (mAbs) against the purified molecules were developed. Epitope maps of the mAbs were obtained on APA molecules absorbed on plastic surfaces or in solution (BIAcore technology). The mAbs were found to be independent or to be different despite binding to adjacent or overlapping epitopes. In Western blot assays some proteins secreted in culture fluid by M. avium, M. kansasii, M. smegmatis or M. xenopi were also labelled by six of the seven antibodies. Conversely one antibody was specific for the proteins from the M. tuberculosis complex (I10-0,3) demonstrating that the APA molecules have some properties or general conformations that are specific for M. tuberculosis and M. bovis.
Isoniazid (INH), one of the most effective antimycobacterial drugs, specifically inhibits, at an early stage of its action, the biosynthesis of mycolic acids, specific mycobacterial lipids which play a central role in the cell envelope architecture of mycobacteria. In the present study, the consequences of the action of INH on the cell morphology of Mycobacterium tuberculosis and Mycobacterium aurum were examined. Electron microscopy was used to observe bacilli which were previously treated with either subinhibitory concentrations of INH or the MIC of the drug, leading to a decrease of 20 to 35% (by weight) of their mycolic acid contents. The earlier effect of INH on the ultrastructure of mycobacteria, as revealed by negative staining of bacilli, was the alteration of the bacterial poles; this event was observed prior to the bacteriostatic action of the drug and was accompanied by a release of material from the poles into the extracellular medium. In a later stage of the drug's action, cell deformation occurred and more extracellular material was seen. The material released following the action of the drug on susceptible mycobacterial cells was identified as being almost exclusively composed of proteins. Labeling of amino acids with 35S prior to and during the action of INH on M. aurum and subsequent analysis of the labeled proteins led to the conclusion that they consisted of secreted proteins which were up to 20-fold oversecreted in the presence of the drug. Competitive enzyme-linked immunosorbent assay with the secreted 45/47-kDa antigen complex of M. tuberculosis demonstrated up to 20-fold oversecretion of these proteins. Taken together, the production of oversecreted proteins following the decrease of the cell envelope mycolate content by INH strongly suggests that mycolic acids may act as a barrier in the export of proteins secreted by mycobacteria.
Interactions of leukocytes with vascular endothelium are important components of inflammation tissue reactions and have been implicated in cardiac transplant rejection and demonstrated to be mediated by cell adhesion molecules (CAM's). The expression of ICAM-1, VCAM-1 and E-selectin in human myocardium is variable and little is known about the expression of LFA-1 and Mac-1 during allograft rejection. This study investigated these CAM's in myocardial biopsies of transplanted hearts (HTX) and of coronary artery disease eligible for coronary artery bypass grafting (CABG) as non-inflammatory controls and explicitly examines vascular endothelium, cardiomyocytes and infiltrating cells. Immunohistochemistry was performed using the APAAP-method and directing specific mouse anti-human monoclonal antibodies against ICAM-1 (CD54), VCAM-1 (CD106), E-selectin (CD62E), alpha-LFA-1 (CD11a), alpha-Mac-1 (CD11b), alpha-p150/95 (CD11c) and the beta2-integrin chain (CD18). CD18, LFA-1 (CD11a), Mac-1 (CD11b) and p150/95 (CD11c) were markedly expressed on infiltrating immunocytes in HTX compared to CABG where no expression of beta2-integrins was observed. Cardiac allografts demonstrated a strong expression of ICAM-1 on vascular endothelium and on infiltrating cells. ICAM-1 was not detected on cardiomyocytes. In CABG a weak expression of ICAM-1 was observed on endothelial cells but not on myocytes. VCAM-1 was expressed on vascular endothelium and perivascular infiltrating cells in HTX but not in CABG. VCAM-1 was not found to be expressed on myocytes. There was no evidence for the presence of E-selectin in any of our biopsy specimens. Our study shows that the study of cell adhesion molecules adds to the pathophysiological understanding of inflammation after transplantation in cardiac disease. This offers a potential for the development of diagnostic tools and new therapeutic strategies.
In a prospective study elastase alpha 1-proteinase inhibitor (E alpha 1PI), polymorphonuclear (PMN) count, the immature to total neutrophil count ratio (I/T ratio), and C-reactive protein (CRP) were analysed in 74 patients (76 cases) with neonatal septicaemia at the time of initial clinical symptoms. At that early stage of the disease, 94% of the patients had abnormal values for E alpha 1PI, 71% for I/T ratio, 61% for PMN count, and only 54% for CRP. PMN count was a poor indicator of septicaemia. Neutropenia, present in 26% of all patients, was related to normal E alpha 1PI in only 4 patients. The combined use of E alpha 1 and I/T ratio was the most sensitive indicator. In all patients irrespective of causative bacteria or disease onset at least one of these parameters was elevated. In early-onset septicaemia (n = 31), normal CRP values occurred significantly more often (63%) than in late-onset sepsis (33%). Even in five of the seven fatal cases, initial CRP measurements were normal. The sensitivity of PMN count and I/T ratio did not differ significantly between early- and late-onset septicaemia. Laboratory changes observed in 18 newborns during the first 3 days of the septic episode show that the rate of pathological values for E alpha 1PI and I/T ratio was highest at the time of initial clinical symptoms and decreased on days 2 and 3. In contrast, CRP reached maximal values as late as day 2 (88% abnormal values), followed by a decrease on day 3. We conclude that the use of E alpha 1PI may improve the laboratory detection of neonatal septicaemia especially if used in combination with I/T ratio.
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C-reactive protein (CRP) has served as a reliable indicator of infectious and inflammatory diseases for a long time. Sequential CRP determinations offer a useful means of monitoring clinical courses and therapeutic effects in patients of any age as its serum concentrations correlate well with clinical symptoms. Especially in pediatric patients, however, venous blood sampling causes many problems. Thus, in our study a new method of CRP analysis from capillary plasma samples was tested and compared with CRP determinations from venous serum samples. 101 pairs of samples simultaneously obtained from 64 pediatric and neonatal patients (mean age of 5.8 months: min. 1 day, max. 5.5 years) were analyzed and compared. A good correlation (r = 0.967) was found for the whole range of measured CRP-concentrations (5-175 mg/l), showing a linear relationship between both methods. Results were analyzed by chi 2-test. Using a cutoff level of 5 mg/l, a sensitivity of 96%, a specificity and a positive predictive value of 98% each and an efficiency of 97% was found. Thus, the CRP determination from capillary blood samples offers a reliable method and a useful alternative for conventional analysis from venous serum.
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Pseudomonas sp. strain A grew with 2-chloro-1,3,5-triazine-4,6-diamine as the sole and growth-limiting source of nitrogen. The substrate was utilized quantitatively and concomitantly with growth and with excretion of a product which was identified as 2-chloro-4-amino-1,3,5-triazine-6(5H)-one. The reaction yielded 1 mol of organic product and 1 mol of NH4+ per mol of substrate.
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A protocol of chronic antepartum surveillance was initiated at the University of Illinois hospitals in 1973 to assess the impact on perinatal mortality. At the same time, a policy of unselected fetal heart rate (FHR) monitoring was initiated to judge the effect on the intrapartum stillbirth rate. The impact of both programs played a significant role in the decline of perinatal mortality rates for infants weighing more than 1 500 g, from 21.1/1 000 births in 1970--1971 to 14.4/1 000 births in the monitored years 1973 and 1974 (p less than 0.02).
The processing of the dental radiographic films in the darkroom is decisive of the optimal information content of dental radiographs. Proper storage of the films, darkroom lighting according to regulations and standardized film developing are the basic conditions for stable film quality. The indications given are above all intended for aiding the stomatological nurse in taking dental radiographs.
An analysis of histological and clinical findings in 102 keratoplasties confirms that suture loosening is often associated with defects found in Bowman's membrane and in the superficial stroma. These structures of the cornea serve as the major supporting layer for a suture. In cases of more generally weakened corneal tissue, like in keratokonus, suture loosening is also a relatively frequent occurance. In this paper we report on our experiences with correction methods, post-operative care and immunoprophylaxis after correction.
A unique case of congenital heart disease and complete heart block diagnosed by fetal electrocardiogram (ECG) and phonocardiogram recorded initially at 32 weeks gestation is presented. The slow, regular fetal heart rate of approximately 50 beats/min with bizarre QRS and a diamond-shaped murmur beginning with the fetal QRS complex made a diagnosis of complete heart block (CHB) and associated congenital heart disease highly probable. Direct fetal electrocardiograms (FECG) recorded during labor and vaginal delivery at term confirmed the diagnosis of completel atrioventricular block. Cardiac catheterization at 1 day of age showed multiple congenital heart anomalies. The infant developed signs of congestive heart failure and transvenous pacemaker was successfully placed; however, he died at 9 days of age of sepsis and renal failure.
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