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D Bauer

Publications and source records attributed to D Bauer.

At least 109 records · Page 6Linked to original sources
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↗
PubMed1993

Identification of differentially expressed mRNA species by an improved display technique (DDRT-PCR).

We have significantly improved a method originally developed by Liang and Pardee [Science 257 (1992) 967-971] to display a broad spectrum of expressed genes and to detect differences in expression between different cell types. We have analysed various aspects of the technique and have modified it for both, the application to fast and efficient identification of genes and the use with automatic analysis systems. Based on the mathematical background we have devised the appropriate number of optimal PCR primers. We have also introduced nondenaturating gels for separating double stranded fragments as single bands. By applying the method to regenerating mouse liver, we have identified, out of a total of 38,000 bands, about 70 fragments where the expression of the corresponding genes seems to be differentially regulated at different time points. Application of the method to an automatic DNA sequencer was successfully done. Thus, we have confirmed the usefulness and increased the power of the RNA display technique, which we named differential display reverse transcription PCR (DDRT-PCR), and have extended the range of its application.

Animals↗
PubMed1993

Investigation of a new Cu,Zn superoxide dismutase mutant: the Thr-->Arg 137 derivative.

The preparation and biophysical characterization of a mutant of superoxide dismutase in which the native Thr 137 has been substituted with a positive Arg residue are reported. Thr 137 forms, together with Arg 143, a bottleneck at the entrance to the active-site Cu ion. The geometry of the Cu ligands shows only minor changes after the above substitution. However, the enzymatic activity of the Arg 137 mutant is smaller than that of the wild type at physiological ionic strength and approaches that of wild type in the limit of zero ionic strength. The binding constant of the anion N3-, which had previously been shown to be a good probe of the O2- substrate, is increased about 20-fold in the mutant with respect to the value found in the wild type. These results are discussed on the bases of the whole charge of the cavity and the possible change in the conformation of the active-site channel.

Amino Acid Sequence↗
PubMed1993

Immunobiology of Acinetobacter baumannii and genospecies 3.

Five representative, taxonomically and serologically defined clinical isolates of Acinetobacter baumannii and genospecies 3, and A. baumannii strain ATCC 19606 were examined for immunogenicity in rabbits following experimental bacteremia. All rabbits seroconverted as determined with the aid of the tube O-agglutination, indirect hemagglutination, and enzyme-linked immunosorbent assay (ELISA) procedures. Immunoblots detected over twenty immunogenic, proteinase-K-degradable polypeptide antigens in trichloroacetic acid extracts, outer membrane protein fractions, and mechanically disrupted (type MM2 mixer drill) cell preparations. Sodium periodate-susceptible phenol-water and phenol-chloroform-light petroleum lipopolysaccharide (LPS) extracts proved to be immunogenic for the rabbits as well. Convalescent sera from two patients with documented bacteremia due to genospecies 3, serovar 4, likewise revealed numerous anti-polypeptide and anti-LPS antibodies comprising the immunoglobulin G (IgG) and the IgM class.

Acinetobacter↗
PubMed1993

Histological findings in a falloposcopically retrieved isthmic plug causing reversible proximal tubal obstruction.

We present the case of a 33-year-old woman with a 10 year history of infertility. Transvaginal falloposcopy revealed a proximal tubal occlusion (PTO) on the right due to a tissue plug. The plug was removed during dilatation of the tubal lumen. After the procedure patency for dye was restored. Histological and immunohistochemical findings--for the first time, to the best of our knowledge, performed in a falloposcopically retrieved plug--revealed the diagnosis of an inflammatory polyp arising from the tubal mucosa with focal calcifications. Local obstructive inflammatory residues of a previously treated tubal endometriosis, which was accompanied by features of salpingitis isthmica nodosa, are considered the most likely cause for this condition. Other possible aetiological factors responsible for PTO are discussed.

Adult↗
PubMed1992

A 41.7 kDa serine protease from Clostridium perfringens type A: degradation of purified human serum proteins.

Two clinical isolates of Clostridium perfringens type A produced a novel caseinolytic serine protease. Both enzymes had a molecular weight of 41.7 kilodaltons and an isoelectric point of 9.1. The two enzymes were immunogenic for rabbits and closely related serologically. Both enzymes partially degraded the heavy chains of human immunoglobulins (Ig) G and IgM, but not IgA. Purified human complement (C) components C3, C5, C8, and C9 were attacked; C1q was refractory. Both enzymes were active against human transferrin, alpha 1-antitrypsin, alpha 2-macroglobulin, haptoglobin, type III fibrinogen, and fibronectin. C-reactive protein was refractory.

Blood Proteins↗