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Biomedical subjects

B Weber

Publications and source records attributed to B Weber.

At least 235 records · Page 13Linked to original sources
PubMed1995

Endoscopic features of Helicobacter pylori-related gastritis.

BACKGROUND AND STUDY AIMS: It is still controversial whether certain endoscopic features can be used to diagnose Helicobacter pylori (Hp)-related gastritis. To clarify this issue, we performed two consecutive prospective studies. PATIENTS AND METHODS: In the first study, we tried to identify endoscopic criteria associated with Hp-related gastritis from a total of 66 predefined gastric features on endoscopy. These features were selected by a stepwise logistic regression analysis in 101 patients. The validity of these features gained from this first study was then evaluated in a second study in 86 patients (40 with Hp gastritis, 8 with Hp-unrelated gastritis and 38 with normal gastric mucosa). RESULTS: Three features, namely an abnormal antral surface texture, a mammillated corpus surface, and white antral erosions, were identified in the first study as independent predictors of Hp-related gastritis. However, the sensitivity and specificity of these three criteria, as assessed in the second study, were only 75% and 63% respectively. CONCLUSIONS: We conclude that it is not possible to diagnose Hp-related gastritis on the basis of the endoscopic appearance alone. The diagnosis should be based on other criteria, such as a rapid urease test, or a histological examination of gastric biopsies, or both.

Adult↗
PubMed1995

Short-term and sustained renal effects of angiotensin II receptor blockade in healthy subjects.

We investigated the short-term and sustained hormonal and renal effects of angiotensin II (Ang II) receptor blockade in normotensive healthy volunteers. Twenty-four subjects maintained on a fixed sodium diet were randomized to receive for 8 days a placebo or 10 or 50 mg doses of the Ang II antagonist irbesartan (SR 47436, BMS 186295) according to a double-blind, parallel group design. Plasma renin activity, plasma immunoreactive Ang II and aldosterone levels, blood pressure, renal hemodynamics, and urinary electrolyte excretion were measured for 8 hours after the first and eighth administration of each dose of irbesartan or placebo. Ang II receptor blockade with irbesartan induced a dose-dependent compensatory increase in plasma renin activity and plasma angiotensin levels and a significant decrease in plasma aldosterone levels. The compensatory rise in plasma renin activity and Ang II levels was more pronounced on day 8, reflecting a long duration of the blocking effect of irbesartan. Irbesartan induced small changes in blood pressure and did not significantly modify renal blood flow and glomerular filtration rate. However, a significant decrease in filtration fraction was observed during receptor blockade on days 1 and 8. The tubular effects of irbesartan were characterized by a dose-dependent increase in sodium and chloride excretions. Interestingly, the cumulative natriuretic response to Ang II receptor blockade was similar on days 1 and 8, suggesting that in these subjects, renal Ang II receptors are not blocked over 24 hours during repeated administration even though this antagonist has a long duration of action (t1/2 of 15 to 17 hours).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Current treatment strategies in acute distal aortic occlusion].

Forty-eight acute distal aortic occlusions were treated on an inpatient basis from January 1973 to December 1993. The mean age was 66 years. Twenty-seven patients had an acute thrombotic occlusion of the distal aorta, and a cardiogenic embolism was the cause of occlusion in 21 cases. The 43 operated patients evidenced a hospital mortality of 32.6% (14/43) and an amputation rate of 7% (3/43). Reperfusion was achieved in 20 patients solely by remote thromboembolectomy with the aid of a Fogarty catheter. A TEA and patch graft were performed in six patients; an extra-anatomic bypass was established in 9 cases and an aortobifemoral bypass in 8. Severe accompanying cardiac diseases were predominant in the patients with an embolic occlusion, whereas severe arteriosclerotic risk factors prevailed in all those with thrombotic occlusions. The mortality among our patients showed a statistically significant (p < 0.05) correlation only with the preoperative ischemia time.

Adult↗
PubMed1994

In vitro phosphorylation of the 46-kDa mannose 6-phosphate receptor by casein kinase II. Structural requirements for efficient phosphorylation.

Some steps in the receptor-mediated transport of newly synthesized mannose 6-phosphate-containing lysosomal enzymes are assumed to be accompanied by changes in the phosphorylation state of receptors. In vitro, the metabolically phosphorylated 46-kDa mannose 6-phosphate receptor (MPR 46) was dephosphorylated by protein phosphatase 2A. The synthetic cytoplasmic domain of MPR 46 was phosphorylated in vitro by casein kinase II. Tryptic phosphopeptide mapping showed that casein kinase II phosphorylates MPR 46 in vitro at the same site that is phosphorylated in vivo. Inhibition studies using synthetic peptides corresponding to different amino acid sequences of the cytoplasmic tail of MPR 46 revealed that the sequence 26-32 (ADGCDFV) contribute to efficient phosphorylation of serine 56. Baby hamster kidney cells were transfected with wild type human MPR 46 cDNA or cDNAs containing mutations in the cytoplasmic tail and assayed for their phosphorylation state in vivo. The phosphorylation of mutant receptors with deleted residues 23-28 (NLVADG) was strongly reduced. These data indicate that residues on the N-terminal side of the phosphorylatable serine 56 may influence the efficiency with which a casein-kinase II-like kinase phosphorylates MPR 46.

Amino Acid Sequence↗
PubMed1994

[Incidence and significance of morphologic and morphometric variants in selective right ventricular angiography in diagnosis of arrhythmogenic right ventricular disease].

BACKGROUND: In arrhythmogenic right ventricular disease it is difficult to find an imaging technique not only to suppose but to diagnose this disease. PATIENTS AND METHOD: In order to assess the value of selective right ventricular angiography in 104 patients with arrhythmogenic right ventricular disease (n = 53), WPW-syndrome (n = 2), sarcoidosis (n = 1), atrial septum defect (n = 8), dilative cardiomyopathy (n = 8), mitral valve disease (n = 17) and normal patterns (n = 15) right ventricular angiography was performed in biplane 30 degrees RAO/60 degrees LAO projection. Quantitative criteria such as RVEDVi, RVEF, regional wall motion in infundibular, inferior, apical and anterior segments and qualitative criteria such as deep horizontal fissures in trabecular hypertrophy, "pile d'assiettes" phenomenon and enddiastolic bulges with loss of trabecular structure were analysed. RESULTS: After extensice statistical analysis enddiastolic bulges with loss of trabecular structure and in less circumstance segmental contraction impairment of the right ventricle are the most valuable angiographic signs in order to diagnose ARVD. CONCLUSION: The best definition of arrhythmogenic right ventricular disease is obtained by extensive angiographic analysis with measurement of oxygen saturation and pressure curves in different positions, coronary angiography and biventricular angiography in order to distinguish between some in regard to right ventricular involvement similar cardiac entities.

Adult↗
PubMed1994

U-type exchange in a paracentric inversion as a possible mechanism of origin of an inverted tandem duplication of chromosome 8.

A mentally retarded male with dysmorphic features was found to have a de novo 46,XY,inv dup(8) (p.23.1-->12). Confirmation of the segments duplicated in the rearrangement was achieved by biochemical analysis of glutathione reductase, which maps to 8p21.1, and DNA studies using the chromosome specific probe y-19-1D (D85131), which maps to 8p21. Assay of cathepsin B, which has been localised to 8p22, did not differ from controls with normal chromosomal constitution. DNA studies using the Defensin 1 gene probe, which maps to 8p23, showed a previously undetected deletion of that segment. We propose that the inverted tandem duplication/deletion arose as a single U-type exchange within an inversion loop.

Abnormalities, Multiple↗
PubMed1994

Low correlation of human cytomegalovirus DNA amplification by polymerase chain reaction with cytomegalovirus disease in organ transplant recipients.

Seventy-five organ transplant recipients underwent prolonged virological and serological follow-up for early detection of human cytomegalovirus (HCMV) infection after transplantation. HCMV DNA detection by nested polymerase chain reaction (PCR) and HCMV early structural antigen (pp65) detection were carried out in 576 peripheral blood leucocyte (PBL) samples. Furthermore, 563 blood specimens were investigated by a commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of specific immunoglobulins G, M, and A against HCMV structural antigens. In eight of nine symptomatic organ transplant recipients, HCMV DNA was detected in one or more consecutive blood samples. HCMV DNA PCR was also positive in one or more samples from eight patients who never developed HCMV-related symptoms. HCMV pp65 antigen was detected almost exclusively in PBL samples from organ transplant recipients suffering from HCMV disease. However, antigenaemia was not detected in four PCR positive patients presenting clinical signs attributable to HCMV infection. Two of the initially HCMV DNA positive samples were not confirmed by retesting and hybridisation. The results of the present study demonstrate that despite the high specificity of nested PCR, HCMV DNA may be detected in the absence of clinical symptoms attributable to HCMV infection. In asymptomatic reactivation, limited replication of viral DNA may be responsible for positive results of PCR without any clinical relevance. In this context, pp65-antigen detection from PBL seems to have a better prognostic value, but is not always detected when clinical symptoms are present.

Antigens, Viral↗
PubMed1994

Replication of human cytomegalovirus in a rhabdomyosarcoma cell line depends on the state of differentiation of the cells.

The replication of human cytomegalovirus (HCMV) was investigated in a new human rhabdomyosarcoma cell line (KFR) with morphological and biochemical characteristics of fetal striated muscle precursors (rhabdomyoblasts). KFR cells exhibited the unique property for spontaneous morphological transformation from a poorly-differentiated state into well-differentiated (myotube-like) rhabdomyoblasts. The poorly-differentiated rhabdomyoblasts promoted both complete viral gene expression and the production of infectious virus. In contrast, in well-differentiated rhabdomyoblasts HCMV infection was abortive. The results showed that replication of HCMV in this human rhabdomyosarcoma cell line depended on the state of cellular differentiation.

Antigens, Viral↗
PubMed1994

In vitro effects of retinoic acid on mouse incisor development.

The developing dentition is known to express the complete set of retinoic acid (RA) nuclear receptors and cytoplasmic RA-binding proteins (CRABPI and II), and RA is required for in vitro mouse molar morphogenesis, so the role of RA during in vitro mouse incisor development was investigated. Histological procedures, immunocytochemical detection of proliferating cells, immunofluorescence detection of laminin, and in situ hybridization with RNA probes for CRABPI and II were done on the tooth-germ cultures either in the presence or in the absence of RA. RA appeared to control initial morphogenesis, particularly the asymmetrical growth of the cervical loop, and to regulate required differential mitotic activity. RA seemed also to be involved in asymmetrical laminin deposition. The distribution of the CRABP gene transcripts was similar during in vivo and in vitro incisor development. However, CRABPI gene transcript distribution in the labial part of the epithelial loop was detected in vitro only in the presence of RA. A direct role of the CRABPs during tooth development is, however, unlikely because Ch55, a synthetic RA analogue that does not bind to CRABP, had the same effects as RA on in vitro incisor development.

Animals↗
PubMed1994

A study of human reovirus IgG and IgA antibodies by ELISA and western blot.

Immunoglobulin A and G reactivities to human reovirus were investigated comparatively by Western blot and ELISA in a collection of 120 serum samples. Five different reovirus polypeptides of molecular weights of 127, 79, 54 42 and 40 kDa were visualized by polyacrylamide gel electrophoresis. Of 80 anti-reovirus ELISA-IgG positive serum samples, 97.5% and 15.0% reacted with one or more virus-specific bands in the IgG and IgA Western blot respectively. The 127 and 79 kDa proteins reacted with 100% and 96.2% of the IgG Western blot-positive serum samples (n = 78). IgG reactivities to the 40, 54 and 42 kDa proteins were detected in 96.2%, 80.8% and 20.5% of the immunoblot-positive sera. Compared to the Western blot, the ELISA had a specificity of 94.9% for IgG and 96.3% for IgA detection. The sensitivity of specific IgG and IgA detection by ELISA were 96.3% and 100%, respectively. Using the ELISA, a seroepidemiological survey was carried out on 850 sera collected from October 1989 to September 1992. The overall prevalence of reovirus IgG and IgA antibodies were 53.5% and 15.5% respectively. An age dependent increase of the seroprevalence of anti-reovirus IgG was observed. In contrast, the prevalence of IgA antibodies remained constant during childhood. Seroprevalence peak levels were observed in the 9-11, 20-29, 40-49 and > or = 60 years age group. The results of the study suggest that antireovirus IgG antibodies may persist lifelong, whereas IgA antibodies are detectable for a short time and may indicate a recent reovirus infection. The development of a sensitive and specific ELISA assay for the detection of class-specific immunoglobulins permits further investigation of reovirus infections and may contribute to improving the serological diagnosis of recent infection.

Adolescent↗
PubMed1994

Comparison of two hybridization assays for the rapid detection of PCR amplified HSV genome sequences from cerebrospinal fluid.

Rapid diagnosis of herpes simplex encephalitis (HSE) can only be achieved by the polymerase chain reaction (PCR). In order to carry out PCR under routine conditions, it is of great importance to establish an easy DNA extraction protocol and especially a rapid and sensitive DNA detection method. In the present study, two different solid phase hybridization assays (Gen-Eti-K-DNA Enzyme Immunoassay (DEIA), Sorin Biomedica, Italy and Enzymun-Test DNA detection, Boehringer Mannheim, Germany) were compared for detection of PCR amplified HSV DNA polymerase genome region, using standard primers, from cerebrospinal fluid (CSF) samples. 122 CSF samples obtained from patients suffering from encephalitis and hospitalized at the University Clinics of Frankfurt and Graz during the period January 1992 to July 1993 were tested. To ascertain the sensitivity of the hybridization assays, dilution series of a plasmid, encoding the amplified region of the polymerase gene, were investigated. The detection limit of the DEIA assay was one copy of the plasmid/microliter, and the lowest amount of DNA which could be detected by the Enzymun assay as well as Southern blot was 10 copies/microliter. 15 CSF samples obtained from patients with HSE were found positive by the three assays. Concordant results were also obtained with CSF samples from non-HSE patients. The results of this study show that new hybridization systems guarantee a fast and high-sensitive detection of amplified HSV DNA. HSV PCR in CSF can be carried out routinely by the combined use of rapid hybridization and a simple extraction procedure.

Base Sequence↗
PubMed1994

Serological diagnosis of cytomegalovirus infection: comparison of 8 enzyme immunoassays for the detection of HCMV-specific IgM antibody.

BACKGROUND: Recently, numerous commercial ELISA kits for the detection of HCMV-specific IgM antibodies have been developed and are available on the international market. OBJECTIVE: The aim of the present study was to compare eight different ELISAs for the early serological diagnosis of HCMV infection. STUDY DESIGN: A panel of paired sera obtained from patients suffering from primary or secondary infection and potential cross-reactive serum samples positive for IgM antibodies against other herpesviruses, antinuclear antibody and rheumatoid factor were investigated with 5 indirect ELISAs (1-5) and 3 mu-capture assays (ELISAs 6-8). RESULTS: The highest sensitivity for IgM detection was achieved by a mu-capture assay (ELISA 8) and a traditional indirect ELISA (4). Their respective sensitivities were 78.0 and 76.0%. Overall, mu-capture immunoassays (ELISAs 6-8) detected HCMV infection earlier than indirect ELISAs (1-5) and showed a higher sensitivity for antibody detection in dilution series of IgM positive serum samples. Whereas ELISAs 1, 2, 5 and 6 showed a specificity of 100%, the alternative assays were affected by a variable number of false positive results obtained by testing potential cross-reactive serum samples. Their specificities ranged from 72.0% (ELISA 8) to 96.0% (ELISA 3). CONCLUSION: The results of the present study show that recent mu-capture and indirect ELISAs permit a relatively sensitive and reliable diagnosis of HCMV infection. Cross-reactive antigens and interference from antinuclear antibody may limit the specificity of commercial kits.

Journal Article↗
PubMed1994

Typing and strain differentiation of clinical herpes simplex virus type 1 and 2 isolates by polymerase chain reaction and subsequent restriction fragment length polymorphism analysis.

In the present study, different combinations of primers were investigated for PCR amplification and typing of clinical herpes simplex virus type 1 (HSV-1) (n = 22) and herpes simplex virus type 2 (HSV-2) (n = 12) isolates. Intratypic strain differentiation was performed by restriction fragment length polymorphism (RFLP) analysis of different PCR amplified HSV genome regions. Enzymatic amplification of HSV DNA from all the clinical isolates could be achieved using primer combinations DNAP5/DNAp3-1 (HSV-1), DNAP5/DNAP3-2 (HSV-2). With the primer pair corresponding to the thymidine kinase (TK) genome region, amplification of all the HSV-1 isolates was only possible by nested PCR. With primers HSV UP/DOWN, 10 of 12 HSV-2 isolates could be detected. HSV typing by type-specific primers DNAP5/DNAP3-1 (HSV-1), DNAP5/DNAP3-2 (HSV-2) or restriction enzyme analysis (Ava II) of amplified DNA with HSV-specific UP/DOWN primers showed results which concorded with serotyping by monoclonal antibodies. RFLP analysis of the PCR products using selected restriction enzymes showed sufficient diversity of profiles among strains to differentiate all the HSV-1 isolates and to distinguish four groups of HSV-2 isolates. Amplification of HSV DNA from clinical isolates with subsequent typing and strain differentiation represents a valuable alternative to conventional methods (virus isolation, serotyping and restriction fragment analysis of the entire genomic DNA) and may be suitable for the study of HSV transmission and pathogenesis, especially in labour-intensive clinical samples with low levels of virus replication (i.e. cerebrospinal fluid, vitreous fluid and corneal transplants).

Base Sequence↗
PubMed1994

Evaluation of a new automated microneutralization assay for the quantitative detection of neutralizing antibodies against enteroviruses.

An automated microneutralization assay for the quantitative detection of neutralizing antibodies (NA) against polioviruses and non-polio enteroviruses (NPEV) using a pipetting roboter (Tecan RSP 5072) was established and compared to the conventional manually performed test procedure. The qualitative neutralizing antibody detection was not significantly influenced by the assay system (manual or automated assay). Concerning the quantitative antibody detection, two-fold titre differences between the two test systems were observed in only 2.3% of the 260 serum samples investigated. The intra-assay and inter-assay variability of the quantitative detection of neutralizing antibodies using the automated assay proved to be very low. The quantitative detection of neutralizing antibodies using an automated pipetting robot permitted the testing of large numbers of samples within a shorter period and with less labour intensity as compared to the manually performed assay. Therefore it represents a valuable alternative to the conventional microneutralization test, especially for the serodiagnosis of non-polio enterovirus infections in large sample collectives, assessment of immunity to polioviruses and for seroepidemiological surveys.

Animals↗
PubMed1994

Quantitative detection of neutralizing antibodies against polioviruses and non-polio enteroviruses (NPEV) using an automated microneutralization assay: a seroepidemiologic survey.

A seroepidemiological survey for the assessment of immunity against polioviruses and non-polio enteroviruses (NPEV) seroprevalence was performed using a recently established automated microneutralization assay. The seroprevalences of neutralizing antibodies against Coxsackie viruses B1-B6, and A9, echoviruses 6, 9, 11, and 30, and polioviruses 1, 2, and 3 were investigated in serum samples collected over a period of 30 months (January 1990 to June 1992). Overall, NPEV seroprevalence ranged from 8.3% (Coxsackie virus B6) to 69.8% (echovirus 30). Age-related increases of seroprevalence were only observed for Coxsackie viruses B2 and A9. Relatively low antibody titres were found, the average antibody titre being the highest for Coxsackie virus B2 (1/55.4). The overall poliovirus seropositivity rate reached 80%. The highest seroprevalence was observed in the higher age groups (> or = 50 years). A relatively high proportion (7%) of individuals did not show neutralizing antibodies against all the three poliovirus serotypes. The results of our study have shown that, using an automated microneutralization assay, it is possible to perform seroepidemiological surveys in large patient populations. Until now, no comparable study concerning the NPEV seroprevalence has been performed.

Adolescent↗
PubMed1994

A two-site monoclonal antibody ELISA for the quantification of group V allergens in grass extracts.

A two-site solid-phase enzymimmunoassay was used for the quantification of group V allergen in grass pollen extracts in mass units. The assay is based on the monoclonal antibodies (MoAbs), 1D11 and 3B2 which recognize different epitopes on the standard Phl p V. The MoAb-ELISA is very sensitive (15-100 ng/ml Phl p V) and highly specific for group V allergens. Six pollen extracts of different grasses demonstrated parallel binding curves. The group V content ranged between 73 and 673 micrograms/ml in the extracts. The International Standard of Phleum pratense (IS 82/520) contains 400 micrograms/ml Phl p V. A good correlation was observed between the group V content and RAST inhibition, with the exception of Poa pratensis.

Allergens↗