Search PubMed⌕ Search

Biomedical subjects

D Bauer

Publications and source records attributed to D Bauer.

At least 55 records · Page 3Linked to original sources
PubMed1997

Human renin binding protein: complete genomic sequence and association of an intronic T/C polymorphism with the prorenin level in males.

The role of renin binding protein (RnBP) in human (patho)physiology, despite its biochemical characterization, is as yet unclear. RnBP has been shown to bind and inactivate renin, a key player of the blood pressure regulating renin-angiotensin system. This renders the RnBP gene a promising candidate gene in human hypertension. Herein, a molecular genetic approach was employed to investigate if RnBP might affect renin, prorenin and/or blood pressure levels. Sequencing of the human Xq28 chromosomal region provided the precise chromosomal location and full genomic sequence of the RnBP gene. All 11 exons, adjacent intronic splice sites and the promoter region were sequenced in 20 patients with essential hypertension of early onset and possible X-linked inheritance and in four normotensive individuals. The only variant found was a single base exchange polymorphism 61 base pairs upstream of the intron 6/exon 7 boundary (T61C). Several cardiovascular parameters, the renin, and prorenin levels and the T61C allele status were determined in 505 Caucasian individuals. Male individuals without medication who were hemizygous for the C allele were characterized by lower prorenin levels (196 +/- 15 versus 256 +/- 12 mU/l, P = 0.05) and a significantly higher renin/prorenin ratio (10.7 +/- 1.5 versus 7.7 +/- 0.3%, P = 0.002), whereas no variations in circulating renin, blood pressure, heart rate and left ventricular mass index were associated with the C allele. No significant association was observed in women. The data do not exclude a role of RnBP in essential hypertension. The complete genomic structure of the RnBP gene, including the identified repetitive sequence elements, provides an essential tool for further studies of the RnBP gene in hypertensive patients with a different genetic background.

Base Sequence↗
PubMed1997

Ataxia-telangiectasia locus: sequence analysis of 184 kb of human genomic DNA containing the entire ATM gene.

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder involving cerebellar degeneration, immunodeficiency, chromosomal instability, radiosensitivity, and cancer predisposition. The genomic organization of the A-T gene, designated ATM, was established recently. To date, more than 100 A-T-associated mutations have been reported in the ATM gene that do not support the existence of one or several mutational hotspots. To allow genotype/phenotype correlations it will be important to find additional ATM mutations. The nature and location of the mutations will also provide insights into the molecular processes that underly the disease. To facilitate the search for ATM mutations and to establish the basis for the identification of transcriptional regulatory elements, we have sequenced and report here 184,490 bp of genomic sequence from the human 11q22-23 chromosomal region containing the entire ATM gene, spanning 146 kb, and 10 kb of the 5'-region of an adjacent gene named E14/NPAT. The latter shares a bidirectional promoter with ATM and is transcribed in the opposite direction. The entire region is transcribed to approximately 85% and translated to 5%. Genome-wide repeats were found to constitute 37.2%, with LINE (17.1%) and Alu (14.6%) being the main repetitive elements. The high representation of LINE repeats is attributable to the presence of three full-length LINE-1s, inserted in the same orientation in introns 18 and 63 as well as downstream of the ATM gene. Homology searches suggest that ATM exon 2 could have derived from a mammalian interspersed repeat (MIR). Promoter recognition algorithms identified divergent promoter elements within the CpG island, which lies between the ATM and E14/NPAT genes, and provide evidence for a putative second ATM promoter located within intron 3, immediately upstream of the first coding exon. The low G+C level (38.1%) of the ATM locus is reflected in a strongly biased codon and amino acid usage of the gene.

Ataxia Telangiectasia↗
PubMed1997

SICONA: the development of signal conditioning communication aids for the severely hearing impaired.

Project SICONA endeavours to satisfy the specific needs of the severely hearing impaired. A complex system is introduced, consisting of several speech processing modules to achieve an improvement of the communication ability within the target group. The basic methods are improving the S/N-ratio by multichannel wireless FM transmission, enhancing weak consonants and second formant information and transposing the unvoiced fricative /s/ into the residual hearing area. Single case studies indicate the effectiveness of the proposed methods; improved reception of speech features within the F2 range and successful integration of the replacement /s/ could be shown. Practical useability is achieved by introducing wireless coupling between the miniaturized (SMD technology, ASIC) system components.

Conditioning, Psychological↗
PubMed1996

The genomic organization of a human creatine transporter (CRTR) gene located in Xq28.

During the course of a large-scale sequencing project in Xq28, a human creatine transporter (CRTR) gene was discovered. The gene is located approximately 36 kb centromeric to ALD. The gene contains 13 exons and spans about 8.5 kb of genomic DNA. Since the creatine transporter has a prominent function in muscular physiology, it is a candidate gene for Barth syndrome and infantile cardiomyopathy mapped to Xq28.

Base Sequence↗
PubMed1996

[The prevalence of sleep-related breathing disorders in patients with implanted cardioverter-defibrillators. The effect on the incidence and circadian distribution of malignant ventricular tachyarrhythmias].

OBJECTIVE: To determine the prevalence of sleep-related breathing disorders (SRBD) on patients who, because of malignant ventricular tachyarrhythmias associated with cardiac disease, have an implanted cardioverter-defibrillator (ICD). It was also investigated whether the frequency and circadian distribution of spontaneous ventricular tachycardia and (or) fibrillation (VTF) can be influenced by SRBD. PATIENTS AND METHODS: 29 consecutive ICD patients (28 men, one woman; mean age 64 +/- 8 years) were investigated by multifunction recordings. 22 patients had coronary heart disease, and seven dilated cardiomyopathy. For each patient the number of VIF episodes per month were recorded, as well as the percentage distribution of the episodes during the day per hour and after grouping into four time periods. RESULTS: SRBDs were recorded in 13 of the 29 patients (45%) (apnoea-hypopnea index [AHI] > 10). The other 16 patients had normal findings (AHI < or = 10). Mean frequency of the registered VTF attacks was similar in both groups (0.41/month with AHI < or = 10 vs 0.44/month with AHI > 10; difference not statistically significant). Averaged percentage distribution pattern showed a maximum frequency in both groups between 6 o'clock and 12 o'clock a.m. There was no significant increase of VTF during the night (10 o'clock p.m.-6 o'clock a.m.) in the group with SRBD (19% with AHI > 10 vs 18.2% with ATF < or = 10; difference not significant). CONCLUSION: There was a high prevalence of SRBD in the patients with ICD and underlying cardiac disease. No influence of SRBD on frequency and circadian distribution of VTF was demonstrated in patients with ICD during long-term observation.

Aged↗
PubMed1996

Enhancement of cytomegalovirus infection and acute rejection after allogeneic lung transplantation in the rat.

A possible mechanism of the induction of lung transplant rejection by cytomegalovirus (CMV) infection is the inflammatory upregulation of adhesion ligand molecules on transplant endothelia by the viral infection leading to leukocyte activation. To study this question a rat model of rat cytomegalovirus (RCMV) infection and acute lung transplant rejection was established to study: (1) the influence of RCMV infection on the course of rejection, (2) the influence of rejection on the course of RCMV infection, and (3) the influence of RCMV on adhesion molecule expression and leukocyte infiltration. For this Lew (RT1l) rats received either syngenic (n=25) or allogeneic (BN, RT1n; n=38) left lateral lung transplants. Postoperatively, CsA 25mg/kg was given on days 1-3 and triple drug (CsA, Aza, Pred) immunosuppression was given from days 4-10 to induce systemic RCMV infection and acute rejection developed from postoperative day (POD) 15-25 in allogeneic transplants. In RCMV-positive animals the rejection grade was gradually increased at POD 15 and 18. Furthermore, after allogeneic transplantation an enhanced viral infection of the lung transplant as early as POD 11 was found and increased salivary gland PFU titers on days 20 and 25. In the absence of rejection infiltration a maximal induction of ICAM-1 adhesion molecules was found on lung endothelia in RCMV+ allogeneic animals as compared with noninfected controls. This induction was found to lesser degree for VCAM-1 and MHC class II adhesion ligand molecules. This was accompanied by a significantly increased CD11a+ and CD49d+ leukocyte infiltration into the alveolar interstitium on day 11 and 15 in infected transplants. The results show an enhancement of RCMV infection after allogeneic lung transplantation leading to endothelial activation and recruitment of CD11a/CD49d+ leukocytes. This mechanism may strongly influence transplant inflammation and the long-term course of lung transplant rejection.

Animals↗
PubMed1996

Phenotypic and genotypic characterization of clinically recovered presumptive Acinetobacter baumannii isolates which failed to grow at 44 degrees C.

Eleven clinical isolates of Acinetobacter, which exhibited an identical biochemical profile compatible with genospecies 3 and failed to grow at 44 degrees C, were not agglutinated by polyclonal rabbit immune sera against 26 serovars of genospecies 3. Rather, all 11 isolates reacted strongly with antiserum against serovar 18 of A. baumannii. Macrorestriction (SmaI) analysis of genomic DNA revealed that only one isolate was genotypically different, whereas the remaining ones were either closely related or identical. However, the genomic DNA of the A. baumannii serovar 18 reference strain proved to be genotypically unrelated.

Acinetobacter↗
PubMed1996

Typing of nosocomial strains of Serratia marcescens: comparison of restriction enzyme cleaved genomic DNA fragment (PFGE) analysis with bacteriocin typing, biochemical profiles and serotyping.

Eighty-eight selected clinical isolates of Serratia marcescens, representing 27 putative outbreaks of nosocomial cross-infection encountered during 1980-1995, were tested comparatively by bacteriocin typing, carbon source assimilation tests, serotyping (O and H antigens), and restriction pattern (RFLP) analysis of restriction cleaved (SpeI, XbaI) genomic DNA fragments after pulsed-field gel electrophoresis (PFGE). Serotyping served as the "gold standard" of the phenotypic methods. One pseudo-outbreak (bacteriocin typing incriminated type 26) was uncovered through serotyping as well as the biochemical profile and confirmed by PFGE analysis of genomic DNA. Bacteriocin typing and determination of biochemical profiles disclosed several instances of phenotypic variation; serotyping revealed two episodes of shifts from motility (H12) to nonmotility. Resolution of restricted genomic DNA fragments with the PFGE procedure permitted detection of 27 PFGE patterns (A-M, N-1-N-3, O-1, O-2, P-1-P-3, Q-1-Q-3, R-1-R-3, S-1, and T). Based on the analysis of PFGE patterns against the background of epidemiological data, the number of nosocomically significant strains of S. marcescens could be reduced to 16 (PFGE patterns A-M, N-2, O-1, P-2, and T). It was concluded that PFGE analysis of restricted genomic DNA of S. marcescens was superior to the three phenotypic methods.

Animals↗
PubMed1996

Clusters of nosocomial cross-infection due to Acinetobacter baumannii and genospecies 3: comparison of serotyping with macrorestriction analysis of genomic DNA with pulsed-field gel electrophoresis.

Triplets of isolates representing 20 putative clusters of nosocomial cross-infection due to Acinetobacter baumannii and genospecies 3 were examined comparatively using serotyping and analysis of restriction fragments (SmaI and ApaI) of genomic DNA with the aid of pulsed-field gel electrophoresis. Carbon source assimilation tests disclosed phenotypic variation among 6 to 20 triplets of isolates. Two misleading results of serotyping were encountered. With respect to the presumptive cluster No. 9, one of the genospecies 3 (originally serovar 4) isolates proved to be polyagglutinable upon repeat examination; this particular putative cluster was shown to be a pseudocluster by comparison of the macrorestriction profiles of the respective triple isolates. A strain of A. baumannii serovar 15 had infected 8 patients in a surgical intensive care unit, while a second, genotypically totally different strain of identical serovar had caused infection in one additional patient. With this exception, the correlation between serotyping and analysis of macrorestriction profiles was excellent.

Acinetobacter↗
PubMed1996

Phenotypic variation of clinical Serratia marcescens isolates repeatedly recovered from individual patients.

A total of 129 selected isolates of Serratia marcescens which had been recovered from 50 patients during the 1980-1995 period and which revealed phenotypic variation in terms of bacteriocin (phage tail) susceptibility, carbon source assimilation, or serotype, were reexamined with these three phenotypic methods. Seven isolates (5.4%) were bacteriocin nontypable; all 129 isolates utilized carbon sources and could be serotyped. Fourty-eight isolates from 20 patients yielded unambiguous results with these 3 phenotypic methods and were excluded from further analysis. Among the remaining 81 isolates from 30 patients, isolates from 2 patients revealed phenotypic variation in bacteriocin susceptibility only, whereas isolates from 6 patients showed variant bacteriocin types and variant biochemical profiles, but were of identical serotype. Isolates from 20 patients revealed variant biochemical profiles only. Three patients had become superinfected with strains of S. marcescens of different phenotype and genotype. In 4 patients, previously motile (H12) isolates had become nonmotile (H-). PFGE analysis of XbaI and SpeI-restricted genomic DNA of the 81 isolates of the 30 patients demonstrated the isolates of 22 patients to be genotypically identical. The isolates from 3 patients were closely related by genotype, and those from an additional patient proved to be possibly related. PFGE analysis demonstrated one patient to have become infected by two genotypically different strains of S. marcescens of identical serotype, which, however, differed in bacteriocin type and biochemical profile. It was concluded that PFGE analysis of restricted genomic S. marcescens DNA was superior to the three phenotypic methods examined comparatively. Serotyping was more reliable than bacteriocin typing, and the latter technique yielded fewer phenotypic variants than determination of biochemical profiles among consecutively recovered isolates from patients with long-lasting S. marcescens infection.

Bacterial Typing Techniques↗
PubMed1996

Identification of a gene disrupted by a microdeletion in a patient with X-linked retinitis pigmentosa (XLRP).

The gene for the most frequent from of X-linked retinitis pigmentosa (XLRP), RP3, has been assigned by genetic and physical mapping to a segment of less than 1000 kbp, which is flanked by the marker DXS1110 and the ornithine transcarbamylase (OTC) gene. In search of microdeletions, we have screened the DNA of 30 unrelated patients with XLRP by employing a representative set of YAC-derived DNA fragments that were generated by restriction enzyme digestion and PCR amplification. In one of these patients, a 6.4 kbp microdeletion was detected which was not present in the DNA of 444 male controls. A cosmid contig spanning the deletion was constructed and used to isolate cDNAs from retina-specific libraries. Exons corresponding to these expressed sequences as well as other putative exons were identified by sequencing more than 30 kbp of the critical region. So far, no point mutations in these putative exon sequences have been identified.

Cell Line↗
PubMed1996

Flow cytometric analysis of bronchoalveolar lavage and venous blood lymphocyte phenotype for the diagnosis of acute graft rejection in lung transplant patients. The Lung Transplant Group, Ospedale Maggiore di Milano.

OBJECTIVE: To investigate modifications of phenotype in bronchoalveolar lavage (BAL) and venous blood lymphocytes as markers of acute organ rejection in lung transplant patients. STUDY DESIGN: Five consecutive patients receiving successful single lung transplants between March 1991 and April 1992 were followed for two years; serial bronchoscopies with BAL and transbronchial biopsies (TBBs) were performed. BAL and venous blood lymphocyte cytofluorimetry was performed at every procedure, and an index, (blood T4/T8)/(BAL T4/T8), was computed. RESULTS: The index was always > or = 3 in the two patients who did not have graft rejection and always < 3 in the two patients who had repeated episodes of acute rejection (even when no rejection was apparent). The index was frequently < 3 when cytomegalovirus infection was diagnosed. CONCLUSIONS: Since BAL is far less invasive and carries lower risks than TBB, the index might be considered, if our results are confirmed, for screening patients at high risk of acute rejection. TBB could be used as a confirmatory tool for patients who have an index < 3.

Adult↗
PubMed1996

[HIV infection and opportunistic pathology: the etiopathogenetic considerations and clinico-diagnostic aspects in candidiasis of the oral mucosa].

Opportunistic infections are, together with some specific neoplasias, the main problem facing the physician when treating patients affected with AIDS. In fact complications arising from infections correlated to the syndrome are a major factor in both morbidity and mortality. In recent years, thanks to improvements in diagnostic techniques, it has become possible to diagnose opportunistic infections much earlier than in the past, and the use of new antiviral and antifungal molecules has provided the means for more effective treatment, with lower toxicity. In the present study we examine the clinical and diagnostic implications of opportunistic mycotic pathologies, in particular candidiasis of the oral mucosa, which occurs frequently in HIV-positive and AIDS patients. In determining the clinical, diagnostic and therapeutic aspects of mycosis of the oral cavity, close collaboration with the pathologist is crucial importance to the stomatologist, as well as objective clinical examination and microbiological culture tests.

AIDS-Related Opportunistic Infections↗
PubMed1995

Simplified purification of Listeria monocytogenes listeriolysin O and preliminary application in the enzyme-linked immunosorbent assay (ELISA).

A simplified procedure was developed for purification of listeriolysin O (LLO) of Listeria monocytogenes, consisting of hydroxylapatite adsorption chromatography followed by Sepharose S ion exchange chromatography. The LLO (58 kDa) appeared pure in terms of sodium dodecylsulfate polyacrylamide electrophoresis and immunoblots with polyclonal rabbit immune sera. The purified LLO could be stored at -65 degrees C for 1 year without loss of immunoreactivity. Similarly, flat-bottom microtiter strips from two vendors that had been charged with LLO, could be stored at -65 degrees C for up to 3 months without loss of LLO. Three patients with documented listeriosis developed elevated IgG titres against LLO; 2 of the patients revealed minimally raised IgM titres, as determined with the enzyme-linked immunosorbent assay.

Animals↗
PubMed1995

Immunocytochemical detection of progesterone receptors. A study in a patient with primary pulmonary hypertension.

Primary pulmonary plexogenic arteriopathy (PPPA) is one of the principal conditions in which pulmonary hypertension may be clinically unexpected. It occurs in the lung vessels in the absence of any demonstrable cause. Its high incidence in women of childbearing age combined with reports of disease following delivery of a child or assumption of oral contraceptives suggest that hormonal factors may play a role in the pathogenesis of PPPA. The suspicion that the pulmonary vascular lesions occurring in PPPA could represent the effect of a hormonal mediated vascular hyperreactivity prompted the evaluation of the steroid hormone receptor status on lung tissue obtained from a women suffering from this disease who had a double-lung transplantation. By the immunocytochemical method performed on formalin fixed, paraffin-embedded lung tissue, we showed the presence of progesterone receptors (PR) in the nuclei of the myofibroblasts forming the arterial obstructive intimal proliferations and of the spindle cells present in the walls of the plexiform lesions. To enhance the staining and to facilitate the observation, we used a microwave-based antigen unmasking technique. The lack of estrogen receptors and the presence of PR could have increased, in the case, the sensitivity of the pulmonary muscular arteries to vasoconstrictory compounds. We hypothesize that on this substrate of a presumptive steroid-mediated vasoconstriction the sequence of the histologic lesions characteristic of pulmonary vascular hypertensive disease could have developed.

Female↗