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Biomedical subjects

B Wagner

Publications and source records attributed to B Wagner.

At least 127 records · Page 7Linked to original sources
PubMed1995

Antigenic properties and immunoelectron microscopic localization of Mycobacterium fortuitum beta-lactamase.

Mycobacterium fortuitum is a fast-growing Mycobacterium species which produces a beta-lactamase involved in the intrinsic resistance of the microorganism to beta-lactam antibiotics. An anti-beta-lactamase serum against the purified enzyme was raised in rabbits. Antibody binding was specific for native beta-lactamase, and enzyme activity was partially inhibited by the serum; furthermore, cross-reactions with denatured class A beta-lactamases were observed. This serum was used as a probe in immunogold labeling for the localization of the cell-bound beta-lactamase in both the low-level producer ATCC 19542 (parental strain) and the overproducer mutant D316. By the combination of preembedding immunogold labeling and replica technique, it was shown that the beta-lactamase was uniformly distributed on the whole external cell surface, where it appeared to be associated with a Tween 80-removable capsule-like material. Compared with the parental strain, a much higher level of expression of surface enzyme was observed in strain D316. Surface labeling was more intense in the stationary phase of growth than in exponentially growing cells. The data obtained are interpreted in the context of the intrinsic resistance of M. fortuitum to beta-lactam antibiotics.

Antigens, Bacterial↗
PubMed1995

PCR-based study of conserved and variable DNA sequences of Tritrichomonas foetus isolates from Saskatchewan, Canada.

The protozoan parasite Tritrichomonas foetus causes infertility and spontaneous abortion in cattle. In Saskatchewan, Canada, the culture prevalence of trichomonads was 65 of 1,048 (6%) among 1,048 bulls tested within a 1-year period ending in April 1994. Saskatchewan was previously thought to be free of the parasite. To confirm the culture results, possible T. foetus DNA presence was determined by the PCR. All of the 16 culture-positive isolates tested were PCR positive by a single-band test, but one PCR product was weak. DNA fingerprinting by both T17 PCR and randomly amplified polymorphic DNA PCR revealed genetic variation or polymorphism among the T. foetus isolates. T17 PCR also revealed conserved loci that distinguished these T. foetus isolates from Trichomonas vaginalis, from a variety of other protozoa, and from prokaryotes. TCO-1 PCR, a PCR test designed to sample DNA sequence homologous to the 5' flank of a highly conserved cell division control gene, detected genetic polymorphism at low stringency and a conserved, single locus at higher stringency. These findings suggested that T. foetus isolates exhibit both conserved genetic loci and polymorphic loci detectable by independent PCR methods. Both conserved and polymorphic genetic loci may prove useful for improved clinical diagnosis of T. foetus. The polymorphic loci detected by PCR suggested either a long history of infection or multiple lines of T. foetus infection in Saskatchewan. Polymorphic loci detected by PCR may provide data for epidemiologic studies of T. foetus.

Abortion, Veterinary↗
PubMed1995

Antibiotic patterns associated with fungal colonization in critically ill surgical patients.

Fungal infections (FI) in surgical patients are increasing; mortality approaches 50 per cent. Prior studies identified factors predicting fungal colonization (FC) including broad spectrum antibiotics (BSA). This study investigates antibiotic patterns predicting FC. Other risk factors and outcomes are analyzed. A total of 72 consecutive SICU patients receiving > or = 7 days BSA were followed. None received prophylactic antifungals. Input data: Age, APACHE II, surgical procedure, lines, ulcer prophylaxis, TPN duration, antibiotic/antifungal regimen. Outcome data: FC, FI, length of SICU and hospital stay, mortality. A total of 32 patients (44%) developed FC; five (16%) developed FI (P = 0.08). All infected patients died (P = 0.0002). FC of GU (25%), respiratory (19%), and GI (19%) tracts were common. Multiple site colonization occurred in 25 per cent of colonized patients. Metronidazole and duration of ventilation predicted FC. APACHE II and TPN duration predicted mortality. Mortality occurred exclusively among patients requiring systemic antifungals. Among BSA, only metronidazole independently predisposed to FC. Other predictors of colonization and mortality agree with prior studies. The high mortality among patients requiring systemic antifungals implies that a more aggressive approach to prophylaxis may be warranted.

APACHE↗
PubMed1995

A pathogenetic link between aplastic anemia and paroxysmal nocturnal hemoglobinuria is suggested by a high frequency of aplastic anemia patients with a deficiency of phosphatidylinositol glycan anchored proteins.

The clinical interrelationship between paroxysmal nocturnal hemoglobinuria (PNH) and aplastic anemia (AA) promoted a search for a pathogenetic link. Since the molecular defect in PNH is a failure to express phosphatidylinositol glycan-anchored proteins (PIG-AP), we investigated whether this defect could also be demonstrated on peripheral blood cells of patients with typical AA. Quantification of the expression of PIG-AP was performed by flow cytometry using the monoclonal antibodies (MAbs) CD16 and CD66b for granulocytes, CD14 and CD48 for monocytes, CD48 and CD52 for lymphocytes, and CD55 and CD59 for erythrocytes. We analyzed cells from 52 patients with acquired AA. A PIG-AP-defective population was identified in 27 of 52 patients (52%) in at least one cell lineage. Granulocytes were involved in 25 of 27, monocytes in 18 of 25, lymphocytes in seven of 27, and erythrocytes in seven of 27 AA patients who were affected by a PIG-AP deficiency. The response rate to standard immunosuppressive therapy was significantly higher in the group of patients without a PIG-AP-deficient population than in patients with a PIG-AP-deficient population in at least one cell lineage (85.7 vs. 30.4%; p < 0.0003). Our results demonstrate that on the basis of PIG-AP expression, the proportion of AA patients who show features of typical AA along with a PNH phenotype is substantially higher than previously recognized. The pattern of PIG-AP expression might identify subgroups of AA patients who differ in the underlying mechanism as well as in the course of their disease.

Adolescent↗
PubMed1995

[Validation of the Sleep-Doc-Porti system for ambulatory sleep apnea diagnosis].

The aim of our study was to validate the Sleep-Doc-Porti-System (SDPS), a simple device to monitor patients suspected of suffering from obstructive sleep apnea syndrome (OSAS). This digital recording system measures nasal flow, oxygen saturation, heart rate, and body position. To assess the reliability of results obtained by the SDPS, cardiorespiratory polygraphy and SDPS were performed simultaneously on 48 patients with OSAS (apnea/hypopnea index (AHI) 26 +/- 25) and 10 habitual snorers (AHI = 0.6 +/- 0.7). There was a strong correlation between the apnea index (AI) recorded by the SDPS and the AI (r = 98; p < 0.001) and AHI (r = 97; p < 0.001) obtained by polygraphy. However, the SDPS significantly underestimated the respiratory disturbance index, because hypopneas were not detected by the recorder (AI by SDPS vs. AHI by polygraphy: 19.6 +/- 24.4 vs. 26.7 +/- 25.3; p < 0.01). With the cardiorespiratory polygraphy as standard, the sensitivity of the SDPS in detecting OSAS ranged between 71 and 72%, and the specificity between 91 and 100%, depending on the AHI values of 5, 10, 15 and 20 chosen to define severity of the disease. Reproducibility was assessed in 23 patients who underwent in-home monitoring in two consecutive nights and yielded no evidence of a "first night effect" (AI: 30.9 +/- 24.3 vs. 33.4 +/- 23.3; p = n.s.). In 18 OSAS patients in-home monitoring was able to demonstrate the worsening effect of alcohol on the disease by a significant increase in the AI comparing the night with and without alcohol (AI: 23.1 +/- 11.9 vs. 35.2 +/- 14.8; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Principles of development and design of microsystems.

The state of the art in microsystem design and fabrication is reviewed. The focus is on silicon micromachining, which uses the equipment and processes of IC-technology to produce highly miniaturized, three-dimensional structures, sensors and actuators for various biomedical applications. The micro components can be integrated into surgical instruments, catheters and implants. Thus new functions and a higher level of intelligence are created. Portable microsystems are being developed for chemical analysis and biomedical monitoring. The cultivation and investigation of live cells on chip substrates offers encouraging perspectives for the future.

Artificial Intelligence↗
PubMed1994

The baby chase.

Explore the source record for details and available documents.

Ambulatory Care Facilities↗
PubMed1994

Determination of factor XIII activity by a new photometric assay in plasma and platelets of healthy blood donors.

Crosslinking of fibrin monomers by activated factor XIII (F XIIIa) is a final event in blood coagulation. So the fibrin clot gains mechanical stability and resistance to plasmin degradation which is thought to be essential for normal blood clotting and wound healing (1-3). In addition, changes in plasma F XIII activity were found in several state of disease such as collagenoses, inflammatory bowel diseases, leukemias, subarachnoidal bleeding and delayed fracture healing (4-12). Because approximately 50% of the potential F XIII activity in plasma are present in platelets (1), the additional determination of F XIII activity in platelets is of clinical interest especially concerning platelet transfusions that may exert an additional benefit due to simultaneous substitution of platelet-bound F XIII. The latter differs from plasma F XIII as a dimer containing only a-chains (a2) compared to the plasmatic tetramer carrying additional b-chains (a2b2). We applied a recently described photometric assay suitable for the routine laboratory after adaption to an autoanalyser to determine F XIII activity in plasma and platelets of 64 healthy blood donors.

Adolescent↗
PubMed1994

Treatment of relapsing acute lymphoblastic leukemia in childhood. III. Experiences with 54 first bone marrow, nine isolated testicular, and eight isolated central nervous system relapses observed 1985-1989.

Of 54 children with acute lymphoblastic leukemia (ALL) and first hematological recurrence observed between 1985 and 1989, 31 relapsed while still on treatment and 23 after cessation of therapy. Of the former, only one survived. Of the latter, 11 children survived after a minimum follow-up of 25 months. During the same period, a first isolated testicular relapse was observed in nine boys, of whom six survived, and an isolated CNS relapse in eight patients, of whom three survived. As a rule, survivors of a bone marrow or testicular relapse were doing well while those surviving a CNS relapse had considerable neuropsychological sequelae. These results, compared with those of two preceding studies, suggest that with intensification of front-line treatments, it becomes more difficult to rescue children who relapse, particularly those with a bone marrow relapse while on therapy.

Adolescent↗
PubMed1994

Radio-frequency microtools for particle and liver cell manipulation.

Single particles can be manipulated by applying high frequencies to ultramicro electrode arrays fabricated on planar structures. Heat production can be reduced to the extent that intense electric fields can be applied even to unmodified cell culture media. Animal cells grow normally in the high field (up to 100 kV/m) between such continuously energized multielectrodes. As with laser tweezers [1-3], this technique can capture particles and cells in field traps, generate linear movement, and permit cell cultivation. It can also produce micropatterns of pH gradients, field-cast objects, and control cell adhesion. These microtools may be combined to develop cell separators, microsensors, and controlled-biocompatibility surfaces.

Animals↗
PubMed1994

Shielding effects and hypoxia in photodynamic therapy.

Photodynamic therapy (PDT) is a new modality to treat cancer. In clinical use, the procedure is limited by the poor penetration depth of the curative light, which ranges between 3 and 6 mm. The cause of this situation is not clear. Two hypotheses are discussed: shielding effect or hypoxia. To test both hypotheses, we designed an in vitro model. Suspensions and sediments of OAT-75 cells were incubated at 37 degrees C with pheophorbide a or 13(2)-hydroxy-bacteriopheophorbide a methyl ester, both second-generation sensitizers. Irradiation was done with laser light of suitable wavelength. In all experiments, cell death was seen on the surface of the sediment, i.e., near the border of the oxygen-containing atmosphere and opposite the site of the irradiation beam. Therefore, we should accept the hypoxia thesis.

Absorption↗
PubMed1994

JM9 strains, a new type of group B streptococci from Japan.

JM9 strains isolated from human carriers and patients in several districts of Japan, represent a new serotype of group B streptococci (GBS, Streptococcus agalactiae). They were first detected in 1983 but are meanwhile prevailing among all other GBS serotypes in Japan. Outside of Japan, strains of this type have not been reported until now. In the present work, N-acetylneuraminic acid was detected in all strains investigated, by chemical analysis as well as by interaction with a sialic acid-binding lectin. This component is characteristic of all analyzed GBS type polysaccharides. In a chicken embryo model, all strains exhibited a very strong virulence. Examination of the antibiotic sensitivity revealed that all strains were susceptible to penicillin, cephalothin, clindamycin, mezlocillin, azlocillin, erythromycin, methicillin, chloramphenicol, tetracyclin, oxacillin and sulfamethoxazole/trimethoprim, whereas all strains were resistant against gentamicin, kanamycin and neomycin. Electron microscopic studies revealed for these strains relatively small capsules but unusually thick cell walls. By immunogold labelling, the type polysaccharide, the group polysaccharide, the lipoteichoic acid and in some strains, the protein R were localized.

Animals↗
PubMed1994

Quinapril, hydrochlorothiazide, and combination in patients with moderate to severe hypertension.

This 8-week, double-blind, multicentre study compared the efficacy and safety of the combination of quinapril and hydrochlorothiazide (HCTZ) with each drug as monotherapy. Outpatients with moderate to severe hypertension defined as supine diastolic blood pressure (DBP) > or = 105 mmHg and < or = 120 mmHg at the end of a 2 to 4-week placebo-baseline period were randomly assigned to one of the three treatments: once-daily 10 mg quinapril plus 12.5 mg HCTZ or monotherapy with these doses. After 4 weeks, the doses were to be doubled for the remaining 4 weeks. Three hundred and sixty-eight patients were randomized to double-blind medication; 346 completed the study. Seven patients withdrew due to lack of efficacy. Four patients withdrew due to side effects. In all three treatment groups, clinically significant reductions in DBP were achieved. Combination therapy was statistically more effective than each component taken as monotherapy. Adverse events were infrequent in all treatment groups. No patients experienced symptomatic hypotension or orthostatic hypotension.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Fenoterol metabolism in man: sulphation versus glucuronidation.

1. Plasma levels of fenoterol (F) and its conjugate metabolites were determined in healthy female subjects and in pregnant women treated for preterm labour. Sulphate (S) and glucuronide (G) conjugates could be quantified. 2. In the healthy volunteers, AUC of both the metabolites was half that of parent compound (AUC-S/AUC-F: 0.42; 0.14-1.16) (AUC-G/AUC-F: 0.49; 0.18-0.86) during i.v. administration of the drug and was several fold that of parent drug (AUC-S/AUC-F: 116.9; 36.4-353.3, AUC-G/AUC-F: 19.9; 5.1-57.5) after p.o. administration indicating extensive presystemic elimination. 3. In the healthy subjects, the AUC ratio of G:S was 1.1 (0.5-2.6) and 0.16 (0.10-0.27) after i.v. and p.o. administration, respectively, thus indicating that sulphation is the prevailing metabolic pathway in the presystemic elimination. 4. In patients, concentration ratios were used for the analysis. During continuous i.v. treatment, Css-S/Css-F was 3.8 (2.5-4.8) and Css-G/Css-F was 1.5 (0.7-2.1). During p.o. treatment Csstrough S/Csstrough-F was 69.4 (32.1-145.7) and Csstrough-G/Csstrough-F 9.4 (5.6-13.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1994

[Primary localization of malignant lymphoma in the urinary bladder?].

We report on the case of a malignant non-Hodgkin lymphoma with primary location in the urinary bladder of an 83-year-old woman. Diagnosis was established by transurethral resection of the tumor and histological examination. No clinical signs (e.g. alterations of peripheral blood count) or tumor generalization were observed. To date only 86 cases of primary localization of lymphoma in the urinary bladder have been described, whereas secondary involvement occurs in 5.4-13% of cases.

Aged↗