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M Bitzan

Publications and source records attributed to M Bitzan.

28 records · Page 2Linked to original sources
PubMed1988

Purified verotoxins of Escherichia coli O157:H7 decrease prostacyclin synthesis by endothelial cells.

Two immunologically distinct verotoxins purified from Escherichia coli C600, lysogenized with distinct temperate phages from E. coli strain 933 of serotype O157:H7, were compared by SDS-PAGE and different biological assays. The two toxins termed verotoxin 1 (VT1) and verotoxin 2 (VT2) differing in molecular weight exhibited similar biological activities. Both preparations were toxic for HeLa cells and lethal for mice. Epidemiological evidence of verotoxinogenesis in some cases of hemolytic-uremic syndrome (HUS) and the recent observations of inadequate prostacyclin production by endothelial cells associated with HUS prompted us to study the effect of purified verotoxins on prostacyclin synthesis in rat aortic tissue. Our results demonstrate a significant reduction of prostacyclin by both toxins at picomolar levels. The suppression of prostacyclin release by a lower concentration of VT2 as compared with VT1 reflects the relative potencies of these toxins in HeLa cell toxicity and mouse lethality. The results suggest an effect of verotoxins on endothelial cells and support the concept of these toxins as virulence factors in E. coli.

Animals↗
PubMed1988

Purification and characterization of a phage-encoded cytotoxin from an Escherichia coli O111 strain associated with hemolytic-uremic syndrome.

Cytotoxin production by Escherichia coli O111:H-strain HUS-2 (Hamburg) is associated with a temperate toxin-converting bacteriophage (Tcp-111). E. coli laboratory strain C600 transduced and subsequently lysed by the phage produced and liberated large amounts of cytotoxin (CT111) which was purified by sequential chromatography. When compared with published procedures for toxin release from viable cells, lysis of the C600 culture by the phage was most effective. By SDS-PAGE CT111 as Shiga toxin from Shigella dysenteriae 1 were shown to consist of two polypeptides of MW 31 kd and 4-5 kd. Both toxins share common antigenic epitopes as revealed by immunoblotting and neutralization studies. With rabbit anti-CT111 toxic activity of only 5 out of 8 clinical E. coli O111 isolates was neutralized suggesting the presence of different cytotoxins in E. coli serogroup O111. Taken together, our data established CT111 as a potent cytotoxin with significant enterotoxic and neurotoxic properties similar or identical to Shiga toxin and to Shiga-like toxin I from E. coli O26:H11 and O157:H7 strains.

Adult↗
PubMed1987

Yersinia enterocolitica serodiagnosis: a dual role of specific IgA. Evaluation of microagglutination and ELISA.

The microagglutination technique for the detection of antibodies against Y. enterocolitica, serovars 3 and 9 (corresponding to O-groups I and V), was compared with the conventional tube agglutination. An immunoglobulin class specific, indirect ELISA (polyvalent immunoglobulin, IgG, IgM, and IgA) was established employing as antigens formalinized whole bacteria ("OH"-antigens) and LPS preparations (hot phenol-water extraction). ELISA titers and net absorbancy (ELISA-"units") of single serum dilutions were in good agreement; the same was true for ELISA and agglutination results. Specificity (against healthy controls) and sensitivity of both serologic techniques were comparable. Cross-reacting antibodies against serovars 3 and 9 could be identified in the ELISA. Correct serovar-specific diagnosis was possible in 95% with a single assay (polyvalent Ig assay with LPS-antigen). The sensitivity of the LPS-ELISA was superior to the "OH" antigen assay after infections by serovar 3 strains, and antibodies were detected with LPS preparations for a longer period following reconvalescence. Specific IgA, due to its rapid decrease during reconvalescence, on one hand impresses as a valuable marker for the differentiation of recent disease from uncomplicated past infections, while persistence of IgA appears to be associated with Yersinia-induced arthritis. Persisting IgM but rarely IgA titers were characteristically found in patients with prolonged enteric yersiniosis.

Agglutination Tests↗
PubMed1987

Rubella myelitis and encephalitis in childhood. A report of two cases with magnetic resonance imaging.

Two children are described with postnatally acquired acute rubella which induced neurological disease. The first patient with restricted transverse myelitis (Th 11-12) was remarkable for the positive result obtained by the magnetic response (MR) technique of the spinal cord. In the second patient the clinical examination demonstrated a circumscribed, however severe, lasting defect in the extrapyramidal motor system with facial muscle dystonia and complete anarthria; in the latter case the CSF contained rubella specific IgM five days after the onset of exanthema. No abnormalities were noticed by MR five weeks after the clinical onset. The possible significance of MR imaging in virus-induced encephalomyelitis is discussed.

Adolescent↗
PubMed1987

Intra-atrial malpositions of Silastic catheters in newborns.

The intra-atrial position of Silastic catheters placed in the center of the right atrium was assessed by two-dimensional echocardiography in 25 newborns. In 32% of the infants, the catheter tip was located in the patent foramen ovale, and in another 40% of the infants, the catheter tip was located close to the patent foramen ovale. This placement increases the risk of systemic air and fat embolism. Consequently, the tip of Silastic catheters should be placed just behind the confluence of the superior-inferior vena cava and the right atrium.

Cardiac Catheterization↗
PubMed1983

Significance of Yersinia enterocolitica isolates and antibody titers. A prospective study in patients with enteritis and healthy controls under bacteriological, serological, epidemiological and clinical aspects.

A simple and fast isolation procedure in combination with the search for Salmonella and Shigella spp. has been applied for the screening of Yersinia enterocolitica from the faeces. The microorganisms was isolated from 31 out of 4052 patients with gastrointestinal symptoms (0.8%) and from one out of 2295 healthy individuals (0.04%). 42% of the isolates were detected from infants up to the age of 3 years. Y. enterocolitica was excreted on the average at least 22 days after the clinical onset (n = 29). In 17 out of 24 patients (71%) significant agglutinin titers were demonstrated by the first serological examination one to 13 weeks after clinical onset. Acute diarrhoea, the most prominent symptom, lasted for 15 days and was followed in one third of the cases by a protracted course of approximately eight weeks. A reliable diagnosis of "enteric yersiniosis" rests besides the uncharacteristic clinical symptoms on the isolation of the microorganism and/or the demonstration of specific antibodies in significant titers, preferable with fourfold rise or decrease.

Adolescent↗
PubMedDate not supplied

Differences in verotoxin neutralizing activity of therapeutic immunoglobulins and sera from healthy controls.

Intestinal infection by Escherichia coli O157 and other verotoxin (VT) producing E. coli has been increasingly recognized as an important factor for the causation of classic (enteropathic) hemolytic uremic syndrome (HUS) and hemorrhagic colitis (HC). Toxins most frequently involved are VT1 and VT2. As with other toxin-mediated diseases, administration of immunoglobulin (Ig) may be beneficial. However, little is known about the immune response elicited by the toxin(s), and the prevalence of VT neutralizing antibodies in the healthy population. We studied the capacity of seven Igs and a commercial plasma preparation to neutralize four different VTs (VT1, VT2, VT2c and VT2e). The results were compared with the neutralization titers (NT50%) of normal human serum samples from various age groups. Plasma products and normal sera were separated by protein G affinity chromatography to investigate the factor(s) responsible for VT neutralization. All Igs neutralized VT1 (8 to 96 NT50%). None of them inhibited VT2, VT2c or VT2e effectively. In contrast, none of 40 pediatric, and only one of 20 adult control sera (starting dilution 1:4) neutralized VT1 (25 NT50%). All 60 samples as well as the plasma preparation blocked VT2 (22 to 446 NT50%, median 137), but not VT2c and VT2e. The VT1 neutralizing activity was eluted with the IgG fraction. The VT2 neutralizing activity was not bound by protein G, but was recovered in the IgG-free effluent. In conclusion, therapeutic Igs significantly neutralize VT1, but are largely ineffective against other VTs. In contrast, all control sera inhibited VT2, but rarely VT1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗