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Biomedical subjects

S Franke

Publications and source records attributed to S Franke.

At least 73 records · Page 4Linked to original sources
PubMed1996

Analysis of the enterohemorrhagic Escherichia coli O157 DNA region containing lambdoid phage gene p and Shiga-like toxin structural genes.

In this study, we determined the nucleotide sequence of the p gene contained within a 5-kb EcoRI restriction fragment cloned from Shiga-like toxin II (SLT-II)-converting phage 933W of Escherichia coli O157:H7 strain EDL933. The p gene was 702 bp long and had 95.3% sequence similarity to the p gene of phage lambda. Multiple hybridization patterns were obtained when genomic DNA fragments were hybridized with both p and slt-I, slt-II, or slt-IIc sequences. All O157 isolates also possessed an analog of lambda gene p which was not linked with either slt-I or slt-II. Restriction fragment length polymorphism comparisons of clinical O157 isolates and derivates undergoing genotype turnover during infection were made, and loss of large DNA fragments that hybridized with slt-II and p sequences was observed. To further analyze the DNA region containing the p and slt genes, we amplified fragments by using a PCR with one primer complementary to p and the other complementary to either the slt-I or the slt-II gene. PCR analysis with enterohemorrhagic E. coli O157 and non-O157 strains yielded PCR products that varied in size between 5.1 and 7.8 kb. These results suggest that even within O157 isolates, the genomes of SLT-converting phages differ. The methods described here may assist in further investigation of SLT-encoding phages and their role in the epidemiology of infection with enterohemorrhagic E. coli.

Bacterial Toxins↗
PubMed1995

Incremental value of biplane and multiplane transesophageal echocardiography for the assessment of active infective endocarditis.

In 41 patients with clinical evidence of active infective endocarditis, transesophageal echocardiography was performed in a stepwise manner, starting with evaluation of the monoplane views, followed by the longitudinal plane, and finally by the intermediate planes. Number, location, length, area, density, extent, and mobility of vegetations and abscesses were assessed in the monoplane, biplane, and best intermediate planes to identify and quantify the incremental value of the longitudinal and intermediate planes. Eighty-three vegetations and 6 abscesses were found. In 4 patients (10%) monoplane evaluation yielded false-negative results. There were no false-negative results using the biplane evaluation. However, when compared with multiplane evaluation, additional vegetations were missed in 23% of patients after monoplane and in 9% of patients after biplane evaluation. Three abscesses were missed using the monoplane and 1 was missed using the biplane technique. The area was underestimated in 60% of all vegetations (mean underestimation, 37% +/- 23% [SD] of maximal area) and length in 49% of cases (mean underestimation, 38% +/- 23% [SD] of maximal length) of all vegetations when biplane was compared with multiplane evaluation. Also, with monoplane and biplane evaluation, mobility and density were misinterpreted in 6% and 5% and 17% and 9% of all vegetations, respectively. Thus, multiplane transesophageal echocardiography is more accurate than the monoplane and biplane techniques in assessing patients with active infective endocarditis.

Abscess↗
PubMed1995

Construction of recombinant Shiga-like toxin-IIv (SLT-IIv) and its use in monitoring the SLT-IIv antibody status of pigs.

We constructed and purified recombinant B-subunits of the SLT-IIv as well as tested their usefulness in an immunoblot assay. The slt-IIvB gene amplified by PCR was ligated into the fusion vector pGEX-2T, and expressed in E. coli K 12 laboratory strains. Deletion of the signal sequence was necessary for optimal expression. High quantities of the fusion protein could be purified by affinity chromatography and subsequently used as antigen for immunoblot analysis with serum samples from diseased pigs and healthy controls. IgG antibodies against SLT-IIv were detected in the sera of 11 of 52 (21.15%) healthy pigs. By contrast, only in 1 of 28 (3.57%) serum samples of pigs with edema disease caused by SLT-IIv-producing E. coli we could demonstrate SLT-IIv-specific antibodies. During an outbreak of edema disease, sera from 10 pigs were taken at 4, 20, and 40 days after disease onset to investigate the immune response elicited by SLT-IIv. Immunoblot analysis with the recombinant SLT-IIv fusion protein revealed that the number of IgG-positive serum samples increased within this period of 40 days from one on day 4, to seven on day 20, to ten on day 40; the number of IgM-positive samples also increased from one after 4 days to eight after 20 days. Forty days after disease onset, IgM reactivity was no longer detectable. Since all animals seroconverted in the follow-up sera, the antigenicity of SLT-IIv during infection of pigs seems to differ from that of SLT-II in human hemolytic uremic syndrome where only a minority of patients are known to mount an immune response. The recombinant SLT-IIvB described here may be a possible candidate for vaccination trials.

Animals↗
PubMed1995

Genotyping of Shiga-like toxin genes in non-O157 Escherichia coli strains associated with haemolytic uraemic syndrome.

The pheno- and genotypes of Shiga-like toxins (SLTs) in non-O157 Escherichia coli strains from patients with haemolytic uraemic syndrome were determined. The clinical isolates investigated were from Italy and Germany and belonged to serotypes O22:H8, O26:H-, O26:H11, O91:H-, O111:H- and O128:H-; one isolate was non-typable. SLT genotypes were analysed by complete nucleotide sequence analysis of the B-subunit genes. The results showed that 14 strains possessed slt-I alone, two contained slt-II alone and five isolates harboured both slt-I and slt-II genes. In only two strains were slt-II-related genes found, together with either slt-I or slt-II. These findings indicate that variants of SLT-II are rarely found in non-O157 E. coli isolates from patients with haemolytic uraemic syndrome. Polymerase chain reaction (PCR) with Taq cycle sequencing was found to be a suitable method for classification of slt genotypes.

Bacterial Toxins↗
PubMed1995

Clonal relatedness of Shiga-like toxin-producing Escherichia coli O101 strains of human and porcine origin.

Shiga-like toxin (SLT)-producing Escherichia coli (SLTEC) O101 has recently been associated with hemorrhagic colitis and hemolytic-uremic syndrome in humans. In this study, SLTEC O101 strains from humans and pigs were characterized for clonal relatedness by nucleotide sequence analysis of their slt genes, DNA finger-printing of genomic DNA, and determination of virulence factors. The slt genes of five E. coli O101 strains were cloned and sequenced. For all strains, the deduced amino acid sequences of the B subunits were identical to those of the SLT-IIe present in the classical SLTEC O139 strains that cause edema disease in pigs. The A subunit revealed more than 99% homology to that of SLT-IIe. DNA fingerprinting revealed a high degree of genetic relatedness between the human and porcine O101 isolates. None of the O101 strains investigated had virulence factors frequently found in porcine (F107 fimbriae or heat-stable or heat-labile enterotoxins) or human SLTEC strains (eaeA or enterohemorrhagic E. coli hemolysin). The absence of virulence factors typical of SLT-I- and SLT-II-producing E. Coli together with the presence of SLT-IIe, a toxin previously seen only in porcine E. coli, suggests a new pathogenic mechanism for E. coli O101 infection of humans. For diagnostic purposes, we recommend the use of PCR primers and DNA probes complementary to slt-IIe to correctly identify such strains and to further evaluate their role in human diseases.

Amino Acid Sequence↗
PubMed1995

Development of PCR for screening of enteroaggregative Escherichia coli.

In this study, we determined the sequence of the EcoRI-PstI fragment of the plasmid pCVD432, also termed the enteroaggregative Escherichia coli (EAggEC) probe. A primer pair complementary to this probe was designed for PCR amplification of a 630-bp region. Comparison of the analysis of the EAggEC probe sequence with those in database libraries revealed no significant similarity to any known bacterial gene. Pure cultures of E. coli cells, as well as mixed cultures from stool specimens, were investigated with the PCR assay, the EAggEC probe test, and the adherence test. Of 50 E. coli strains which demonstrated aggregative adherence to HEp-2 cells, 43 (86%) were positive with the EAggEC PCR. All 43 of these strains reacted with the EAggEC probe. Six EAggEC strains gave negative results by both molecular techniques. In contrast, only 4 of 418 (0.96%) strains representing other categories of diarrheagenic E. coli demonstrated a positive PCR result. The PCR was also successful in screening for the presence of EAggEC in enriched cultures grown from stool specimens. Compared with cell culture assays and colony hybridization, our findings revealed that the PCR assay was more rapid, simple, and highly sensitive and can therefore be recommended as a screening method for EAggEC in the clinical laboratory.

Adolescent↗
PubMed1995

[Open thrombendarterectomy of the carotid arteries with routine intraluminal shunt implantation, a reliable method for decreasing the risk of apoplexy--results of 11 years experience with 546 consecutive elective interventions].

The operative removal of haemodynamical significant carotid artery stenosis by endarterectomy nowadays is one of the vascular surgical standard procedures. Purpose of the operation is prevention of ischemic strokes. For a long-term prognostic advantage the patient has to take the risk of perioperative mortality and morbidity. While efforts are being made to minimize this risk, the question of optimal surgical strategy has not yet finally been solved. Since 1982 in our hospital all carotid endarterectomies are carried out with routine insertion of an intraluminal shunt. The distal intima step of the internal carotid artery is secured by a running suture and closure of the longitudinal arteriotomy is accomplished by dacron patch plasty. In this manner 546 successive operations have been performed under general anaesthesia until 1993. Intra- and postoperative mortality was 0.9% with an ischemic cerebral infarction rate of 1.8%. According to the preoperative stage of cerebrovascular insufficiency the frequencies for mortality and perioperative ischemic stroke were 0.6% and 1.3% for CVI I, 0.4% and 0.7% for CVI II and 2.8% and 5.7% for CVI IV. Apart from perioperative mortality for patients with CVI IV, these complication rates are clearly below the suggested limits of the Ad hoc Committee on Carotid Surgery Standards by the Stroke Council of the American Heart Association. Routine use of a temporary, intraluminal shunt in carotid artery operations therefore can be considered as a safe measure, with complication rates still not underbid by those achieved with intraoperative cerebral monitoring and selective shunting.

Aged↗
PubMed1995

Inhibition of adenosine deaminase activity of aortic endothelial cells by extracts of garlic (Allium sativum L.).

Aqueous extracts of fresh garlic (Allium sativum L.) inhibited efficiently the activity of adenosine deaminase (ADA) of cultivated endothelial cells. The IC50 value (range between 6 and 120 micrograms per ml) depended on the origin and storage time of the fresh garlic. The aqueous extraction of dried garlic powder showed also an inhibition if ADA activity, but the IC50 value was in the range of 2.5 mg per ml indicating that parts of the active principle were lost during the preparation of the garlic powder. The inhibition of endothelial ADA by garlic extracts seems to contribute to the hypotensive activity and vessel protective effects of A. sativum L.

Adenosine Deaminase Inhibitors↗
PubMed1995

[Aorto-intestinal fistula as a possible cause of endoscopically undetermined gastrointestinal hemorrhage].

Primary aorto-enteric fistulae are rare, mostly described as atypical first manifestation of an abdominal aortic aneurysm. Spread of elective aortic surgery led to increased appearance of secondary aorto-enteric fistulae as a typical postoperative complication. Gastrointestinal bleeding with endoscopical unclear findings in a patient with aortic aneurysm or history of aortic repair points towards an aorto-enteric fistula. While preoperative diagnosis is not possible in most instances, the proof of an anastomotic aneurysm and/or aortic graft infection hardens the suspected diagnosis of an aorto-enteric fistula decisively. The finding of coincidental mucosal lesions at gastroscopy may not mislead to give up the exclusion of an aorto-enteric fistula, possibly by explorative laparotomy, if suspicion is well-founded. In the present article nine cases of aorto-enteric fistulae treated at the Surgical University Clinic Würzburg between 1982 and 1993 are analyzed retrospectively. Topical questions of diagnosis and therapy are discussed.

Aged↗
PubMed1995

[The immune response in edema disease of weaned piglets measured with a recombinant B subunit of shiga-like toxin II].

An outbreak of edema disease (ED) was monitored in 80 piglets after weaning over a period of 4 weeks. The shedding of Shiga-like toxin-IIe) producing Escherichia coli strains, the serum bactericidal activity (SBA) against SLTEC-IIe, and the antibody response against SLT-IIe were investigated. The antibody response was monitored by utilizing a glutathione-S-transferase (GST) + SLT-IIe B/SUB fusion protein (FRANKE et al., in press) for immunoblot assays. E. coli-strain GO15III (0141:K85ac) was diagnosed as SLT-IIe-producing E. coli by polymerase chain reaction, DNA hybridization and cytotoxicity assays. Maximum excretion of GO15III appeared between days 8 and 15 after weaning. On day 1 after weaning no piglet shed GO15III, while the number increased on day 8 to 53 (66.2%) and on day 15 to 59 (73.8%) of the piglets. 4 week after weaning, GO15III was only isolated from 23 (28.8%) of the piglets. In parallel, serum bactericidal activity against GO15III increased significantly in the sera of 73 (91.2%) piglets, reaching a stable maximum from day 15 on. During the first two weeks after weaning, no piglet yielded detectable SLT-IIe-IgG. However, the number of SLT-IIe-IgG positive piglets increased steadily from day 15. On day 15, 5 (6.2%) piglets were positive in SLT-IIe immunoblot analysis and 29 days after weaning the number increased to 31 (38.8%). These data represent the first serological monitoring of a natural outbreak of edema disease in piglets after weaning by using a recombinant fusion protein (GST+SLT-IIe B/SUB). The recombinant protein proved to be a useful diagnostical tool for monitoring the specific antibody status of piglets.

Animals↗
PubMed1994

Identification of novel ubiquitous and cell type-specific factors that specifically recognize immunoglobulin heavy chain and kappa light chain promoters.

In a search for novel factors that interact with the octamer element, immunoglobulin kappa light chain (V kappa) and heavy chain VH) gene promoters were compared for binding to nuclear proteins from lymphoid cells. Both promoters showed a similar pattern of bound factors, which was entirely different from that seen with the human immunodeficiency virus, type I promoter. Besides OTF-1 (Oct-1) and OTF-2 (Oct-2), at least three additional complexes were observed. Two of these were functionally analyzed: C1, a slowly migrating complex, which was much more abundant in B cells than in non-lymphoid cells, and C4, which appeared to have ubiquitous distribution. As determined by several methods, the protein(s) forming the C1 complex bound on the V kappa gene to a site that partially covers the octamer element, whereas, surprisingly, in the VH gene a region spanning the TATA box up to the transcriptional initiation site was recognized. The ubiquitous C4 complex was analyzed for the light chain promoter. The protein specifically bound to a site immediately 5' to the octamer. By in vitro transcription analysis, we found that C4 augments the octamer-dependent transcription of the V kappa gene. The activation required binding of OTF-1/OTF-2, and C4 could not stimulate transcription by itself, implying a synergistic interaction. Due to the overlapping binding sites, the effect of C1 by itself could not be clearly separated from the C4 effect. However, the specific interaction of C1 with crucial control elements of light chain and heavy chain promoters strongly suggests a functional role in immunoglobulin gene transcription control.

B-Lymphocytes↗
PubMed1994

Isolation and mapping of a cosmid clone containing the human NAT2 gene.

The NAT2 gene encodes for a polymorphic arylalkylamine N-acetyltransferase and thus accounts for the human N-acetylation polymorphism. By a NAT2-specific primer set we have screened a human chromosome 8-specific cosmid library. A positive cosmid clone was mapped by fluorescence in situ hybridization to 8p22. The polymerase chain reaction followed by restriction analysis of the PCR product was used to identify allele 2 to be contained in the cosmid clone.

Arylamine N-Acetyltransferase↗