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Biomedical subjects

C Schuster

Publications and source records attributed to C Schuster.

At least 19 recordsLinked to original sources
PubMed1992

[Prenatal diagnosis of thanatophoric dwarfism].

Thanatophoric dwarfism is a rare malformation, occurring in less than 1:10,000 pregnancies. It can be discovered by standard ultrasound examination, but other skeletal dysplasias such as achondroplasia, achondrogenesis and polydactyly syndromes must be taken into consideration. Sonographic findings are polyhydramnia, narrow chest, symmetric tetramicromelia and macrocephaly. Macrocephaly might cause a problem for vaginal delivery. The narrow chest with secondary lung hypoplasia determines the infaust prognosis.

Adult↗
PubMed1992

Altered murein composition in a DD-carboxypeptidase mutant of Streptococcus pneumoniae.

The muropeptide composition of a Streptococcus pneumoniae mutant in which the DD-carboxypeptidase (penicillin-binding protein 3) gene was interrupted by plasmid insertion close to the 3' end of the gene was examined. Extensive compositional changes were observed: the linear pentapeptide, a minor component of the parental cells, became the most abundant monomeric peptide in the mutant wall, while the proportion of tripeptides that represent the main monomers in the parental cells was greatly reduced. The amount of the major dimer of parental cells, the directly cross-linked tri-tetrapeptide, was also reduced by a factor of 4. It was partially replaced by a novel dimer: the cross-linked product of a linear pentapeptide and a pentapeptide carrying a serylalanine dipeptide substituent on the epsilon-NH2 group of its lysine residue. This dimer together with two other dimeric peptides, each containing the serylalanine cross bridge, became the quantitatively major components of the mutant peptidoglycan.

Amino Acid Sequence↗
PubMed1992

[Nitrogen and chemical oxygen demand burden of waste water caused by trout raising influenced by the protein content of the feed].

A possibility was shown, how to quantify the water content of nitrogen and COD (Chemical Oxygen Demand) from intensive fish production, independent of flow rate and feeding time. The nitrogen excretion could be reduced 50% by feeding a protein reduced fish feed (A: 38.4% XP) compared with an fish feed B contending 47.9% protein (XP). The excretion-compartments were evaluated with the waste water parameter COD. Doing this, it could be shown that the COD input by feed A is reduced 20% in opposite to feed B. Further more the separation of fish faeces would achieve an COD reduction from about 50% to 70%.

Animal Feed↗
PubMed1991

Relatedness between Streptococcus pneumoniae and viridans streptococci: transfer of penicillin resistance determinants and immunological similarities of penicillin-binding proteins.

The occurrence of highly variable penicillin-binding proteins (PBPs) in penicillin-resistant Streptococcus pneumoniae suggested that transfer of homologous genes from related species may be involved in resistance development. Antiserum and monoclonal antibodies raised against PBPs 1a and 2b from the susceptible S. pneumoniae R6 strain were used to identify related PBPs in 41 S. mitis, S. sanguis I and S. sanguis II strains mostly isolated in South Africa with MIC values ranging from less than 0.15 to 16 mg/ml. Furthermore, the possibility of genetic exchange was examined with 30 penicillin-resistant strains of this collection (MIC greater than 0.06 mg/ml) as donors using S. pneumoniae R6 as recipient in transformation experiments. The majority of S. mitis and S. sanguis II strains but none of the S. sanguis I strains could transform penicillin resistance genes into S. pneumoniae R6. All positive donor strains and all susceptible isolates of S. mitis and S. sanguis II strains contained PBPs which cross-reacted with the anti-PBP 1a and/or anti-PBP 2b antibodies. On the other hand, only five of the 14 S. sanguis I strains contained a PBP that reacted with one of the antibodies. This strongly suggested the presence of genes homologous to the pneumococcal PBP 1a and 2b genes in viridans streptococci, and documents that penicillin resistance determinants can be transformed from viridans streptococci into the pneumococcus.

Bacterial Proteins↗
PubMed1991

Activation of Epstein-Barr virus promoters by a growth-factor and a glucocorticoid.

Transforming growth factor-beta (TGF-beta) and a glucocorticosteroid, Dexamethasone (DXM), both cause transcriptional induction of Epstein-Barr virus (EBV) early antigens (EA) in Daudi lymphoma cells. The viral induction occurs through the viral promoter DR overlapping an origin of replication which is active during the lytic cycle. Each hormone requires specific regions on the DR promoter. Since these regions also mediate the action of two viral transcription factors, EB1 and R, it may be emphasized that EB1 and/or R are involved in the EA induction process by TGF-beta and by DXM.

Antigens, Viral↗
PubMed1991

Penicillin-binding proteins in Streptococcus pneumoniae: alterations during development of intrinsic penicillin resistance.

Four out of the five high molecular weight penicillin-binding proteins (PBPs) of Streptococcus pneumoniae are involved in the development of intrinsic penicillin resistance. In beta-lactam resistant laboratory mutants, point mutations in the PBP 2x-genes were identified that result in low penicillin-affinity mutant proteins. In contrast, PBPs 1a, 2x, and 2b of resistant clinical isolates are highly altered as can be recognized biochemically and immunologically; DNA sequence analysis of the PBP 2x gene from resistant strains confirmed these results. The variability of the three PBPs analyzed implies a very heterogeneous gene pool accessible to the pneumococcus that is used for recruitment of resistant PBP genes in wild type strains.

Anti-Bacterial Agents↗
PubMed1991

Evidence for a functional glucocorticoid responsive element in the Epstein-Barr virus genome.

Glucocorticoids induce the expression of Epstein-Barr virus early antigens in latently infected Daudi cells. By sequence analysis, we found that fragment C of the BamHI digested Epstein-Barr virus B95-8 genome contains a region with a large degree of homology to the glucocorticoid responsive element of known glucocorticoid-regulated genes. By transfection experiments in Daudi and HeLa cells, different lengths of this region, cloned in front of the bacterial chloramphenicol acetyl transferase linked to the Herpes Simplex virus thymidine kinase promoter (pBLCAT.2), were assayed for their responsiveness to dexamethasone; our results led us to the conclusion that the hormonal effect observed was mediated by a minimal sequence of 15 base pairs presenting 85% homology with the consensus glucocorticoid responsive element sequence.

Base Sequence↗
PubMed1990

Unusual septum formation in Streptococcus pneumoniae mutants with an alteration in the D,D-carboxypeptidase penicillin-binding protein 3.

An internal 630-bp DNA fragment of the gene encoding penicillin-binding protein 3 (PBP 3) (dacA) of Streptococcus pneumoniae was identified in a lambda gt11 gene bank screened with anti-PBP 3 antiserum. The deduced 210-amino-acid sequence showed a high degree of homology to the low-molecular-weight PBPs 5 and 6 of Escherichia coli and Bacillus subtilis PBP 5. Viable mutants lacking a C-terminal part of PBP 3 were obtained after a plasmid containing the dacA fragment was integrated into the PBP 3 gene by homologous recombination. The truncated PBP 3* was still active in terms of beta-lactam binding. Most PBP 3 was found in the growth medium, indicating that membrane anchoring of PBP 3 is provided by the C terminus, as has been shown for other D,D-carboxypeptidases. The mutant cells grew with a slower generation time than the wild type in the shape of irregular enlarged spheres. In addition, as revealed by electron microscopy, cell separation was severely affected, septa were found unevenly distributed at multiple sites within the cells, and the murein layer appeared variable in thickness.

Amino Acid Sequence↗
PubMed1990

[Electronic data processing-assisted text processing at the clinic and in general practice].

Word processing is currently the most frequent application for personal computers, and a wide variety of standard software is available. The capabilities of modern word-processing software includes the convenient typing and correction of all routine correspondence, as well as the professional layout of scientific manuscripts. The decision to purchase a certain word-processing programm should be made according to local needs and prerequisities. Three to six months may be necessary to fully adapt the organization of a clinic or private practice to the new technology.

Computer Systems↗
PubMed1989

Binding studies of the antiglucocorticoid RU38486 in Daudi and Raji lymphoma cells.

The activity of RU38486 has been studied in Burkitt's lymphoma cells which are Epstein-Barr virus (EBV) positive. The early antigens (EA) of the virus are induced by dexamethasone (DXM) in Daudi but not in Raji cells, whereas a growth factor (transforming growth factor-beta, TGF-beta) induces the EA in both cell lines. RU38486 blocks the EA induction obtained by DXM or by TGF-beta in either cell line. In order to understand the interaction of RU38486, we considered its binding to specific receptors. We first investigated the binding of the antagonist in whole cells at 22 degrees C. A number of specific binding sites higher for RU38486 than for DXM was found, suggesting that RU38486 may bind to the glucocorticoid receptor and also to other cellular structures which we called the antiglucocorticoid binding sites ("AGBS"). To support this hypothesis, competition experiments have been conducted between RU38486 and other steroid hormones (progesterone and testosterone) since it is known that RU38486 is also able to interact with their cognate receptors. Binding studies of RU38486 in vitro at 4 degrees C in the presence of cytosolic extracts from Daudi and Raji cells led to conclusions similar to those drawn from the whole cell experiments: more complexes were formed with RU38486 than with DXM. Finally, the steroid-receptor complexes were incubated with DNA-cellulose. Since the binding measured for RU38486 was higher than for DXM, we suspect that sites different from the classical glucocorticoid receptor sites are also able to interact with DNA. The blockage exerted by RU38486 on the EA induced by glucocorticoids or by non-steroidal molecules and the lack of responsiveness to glucocorticoids in Raji cells are discussed in the light of the present findings.

Binding, Competitive↗
PubMed1989

[Prevalence and incidence of arterial hypertension in patients with kidney calculi treated by extracorporeal shock wave lithotripsy].

Follow-up studies were conducted on 806 patients to investigate the question of whether or not arterial hypertension can develop subsequent to ESWL. First of all, it was determined that 509 of 518 patients who were subjected to ESWL treatment from December 1985 to December 1986 still had normotension (n = 410) or hypertension (RR greater than or equal to, 160/95, n = 99) prior to and on an average of 9.3 months after ESWL. Six hypertensive patients became normotensive subsequent to ESWL. Only 1 patient developed hypertension following ESWL. Secondly, the 288 patients who were subjected to ESWL treatment from May 1982 to May 1984 revealed a 3.1% incidence of arterial hypertension within a period of 3.6 years following ESWL. This incidence, however, only illustrates that there was a pronounced age-related increase in the prevalence of hypertension (0.8% per year) in these study groups.

Adult↗
PubMed1989

[Long-term experiences following extracorporeal shockwave lithotripsy in patients with urinary calculi].

A report is given on the experience we have had over a period of up to 7 years following ESWL treatment in urinary stone patients. 131I-hippuran clearance studies were conducted on 19 patients prior to and 6.6 years subsequent to ESWL. There was no evidence of any degree of deterioration in total renal function or of any form of dysfunction in the kidney treated. Follow-up examinations on 247 patients showed a 7% recurrent stone rate within a period of 3.6 years following ESWL. In 16% of the cases, residual concretions were found 6 months after ESWL, only 4% of which were larger than 5 mm in diameter. In 22%, concretions were discovered 3.6 years after ESWL 36% of which were larger than 5 mm. This size increase in the fragments accounts for the stone growth.

Adult↗
PubMed1989

[Microcomputer systems in urology: hardware--mole's hole or useful equipment?].

The basic concepts and elements of micro- and minicomputer hardware components frequently used in urology are described. For advanced users, the details and trends are discussed in more detail. The interdependence of hardware and operating systems is emphasized. In addition, a method for the evaluation of personal computer performance is presented. Finally, proposals are made concerning purchasing procedures and selection criteria.

Humans↗
PubMed1988

Antagonistic action of RU38486 on the activity of transforming growth factor-beta in fibroblasts and lymphoma cells.

Transforming growth factor-beta (TGF-beta) is a multifunctional protein involved in the control of proliferation, differentiation and other functions in many cell types. The anchorage-independent growth of some established lines of untransformed fibroblasts in soft agar is induced by TGF-beta and requires in addition exogenous EGF for certain target cells, notably rat NRK-49 cells. The formation of colonies of NRK-49F cells is completely inhibited by the synthetic 11-beta substituted nor-steroid RU38486 added at a final concentration of 1.3 X 10(-5) M. We also explored the effect of TGF-beta on Daudi and Raji lymphoma cells by measuring the production of Epstein-Barr Virus (EBV) early antigens (EA). In Daudi cells an induction capacity giving rise to 10-16% positive EA-cells was observed; in Raji cells the induction only reached between 6 and 8%. The induction was partially inhibited by the anti-steroid RU38486 in both systems. Thus, RU38486 not only antagonizes the glucocorticoid hormone action but also interferes with the effects of TGF-beta in fibroblasts and in lymphoma cells. The molecular basis of the interactions observed was investigated by considering (1) the binding to specific receptors, (2) transfection experiments, in order to examine if the interference of the anti-steroid with TGF-beta activities occurs at the transcriptional level as in the case of glucocorticoid induction. The results suggest that the blocking by antiglucocorticoids of the effects of TGF-beta and glucocorticoids, in fibroblasts and lymphoma cells, occurs by different mechanisms.

Animals↗
PubMed1988

[Use of electronic data processing in the urologic clinic and practice--possibilities and perspectives].

The development, present status and future trends in the use of computers in urology in the Federal Republic of Germany are reviewed. The hardware, software required for hospital and private practice and the staff needed are discussed. Proposals are given for the installation and stepwise upgrading of computer systems, from simple text processing units to complex hospital communication systems. Finally new technologies that might considerably change the use of computers in urology are presented.

Computers↗