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F Schulze

Publications and source records attributed to F Schulze.

At least 19 recordsLinked to original sources
PubMed2005

Development of a cell culture assay for the quantitative determination of vaccination-induced antibodies in rabbit sera against Clostridium perfringens epsilon toxin and Clostridium novyi alpha toxin.

Cell culture assays are possible alternatives to replace in vivo neutralization tests currently required for potency testing of clostridial vaccines. Cell culture assays based on the MDCK cell line and the Vero cell line which are sensitive to the Clostridium (C.) perfringens type D epsilon toxin and Clostridium novyi type B alpha toxin, respectively, were developed, and the test conditions were standardized. The antibody titres of vaccinated rabbits measured in vitro were compared with the results of current test procedures recommended by European Pharmacopoeia. The correlation coefficients calculated were significant for all sera tested. The cell culture assays proved to be sensitive, specific, reproducible and reliable. Therefore, these cell culture assays could be suitable in vitro alternatives to the in vivo mouse neutralization experiments required for potency tests of clostridial vaccines, but further validation studies are necessary.

Animal Testing Alternatives↗
PubMed2005

PCR detection of virulence-associated genes in Campylobacter jejuni strains with differential ability to invade Caco-2 cells and to colonize the chick gut.

In this study, the presence of 20 putative virulence genes was examined in 11 Campylobacter jejuni isolates with different colonization and invasion abilities as determined in a chick colonization model and on Caco-2 cells, respectively. The majority of the genes were detected in all strains. Among them, there were genes of the flagellar secretion apparatus like flhA, flhB, flgB, flgE2, the flagellin genes flaA and flaB, invasion-associated genes like ciaB and iamA, the cytotoxin genes cdtA-C, the adhesion related gene cadF, and some genes involved in the colonization process (docA, docB). The plasmid gene virB11 could not be detected in any strain. Specific differences between the isolates were observed only in genes cgtB and wlaN involved in lipo-oligosaccharide (LOS) biosynthesis. The gene cgtB was only detectable in three of five strains with strong colonization and invasion abilities. Probably, wlaN can overcome the lack of cgtB in the two cgtB- isolates.

Animals↗
PubMed2005

Determination of a reference value for N(G), N(G)-dimethyl-L-arginine in 500 subjects.

BACKGROUND: Asymmetric dimethylarginine (ADMA) acts as an endogenous inhibitor of NO-synthase. In the last years ADMA has emerged as a cardiovascular risk factor. The aim of this study was to determine a reference value for ADMA. METHODS: Plasma samples of 500 healthy subjects in the 19-75 year age group were analyzed. Exclusion criteria from this study were smoking, any known significant disease, body-mass-index (BMI) above 30 kg m(-2), elevated plasma lipid levels, impaired renal function, hypertension, and intake of any medication. The ADMA levels were determined by ELISA, (DLD Diagnostics, Hamburg, Germany). RESULTS: Mean ADMA plasma concentration of the total population was 0.69 micromol L(-1) (SD 0.20) and 95% of the measured values were in the range from 0.36 micromol L(-1) to 1.17 micromol L(-1). Women below 50 years of age had lower ADMA levels than men below 50 years of age [0.62 (0.17) micromol L(-1) vs. 0.69 (0.19) micromol L(-1); P = 0.001] and woman above 50 years of age had higher ADMA levels than men above 50 years of age [0.80 (0.22) micromol L(-1) vs. 0.73 (0.20) micromol L(-1); P = 0.036]. A regression analysis of ADMA levels and age was performed for each sex. The regression factor was r = 0.444 for women in a squared regression model (P < 0.001) and r = 0.212 for men in a linear regression model (P < 0.001). CONCLUSION: The study was able to define a reference value for ADMA plasma levels with 0.36-1.17 micromol L(-1) and found sex dependent correlations between ADMA and age. Women showed a significant increase in ADMA plasma levels with onset of menopause.

Adult↗
PubMed2004

Correlation between invasion of Caco-2 eukaryotic cells and colonization ability in the chick gut in Campylobacter jejuni.

In an in vitro cell culture model using Caco-2 cells the adhesion and invasion properties of 11 Campylobacter (C.) jejuni isolates of different origin were studied. Additionally, we investigated the colonization ability of the strains in a chick model. Virtually, all C. jejuni showed cell adherence in the in vitro assay, but there were large differences in the invasion frequencies among the Campylobacter isolates. The colonization ability in the chick gut also differed markedly and enabled the formation of three groups: non-colonizing, weak or delayed colonization and strong colonization ability. On this occasion, we found a putative correlation between invasion of Caco-2 cells and colonization in the chick gut. Non-colonizers are not invasive or only have small invasion indexes. Strains which colonize weakly or exhibit delayed colonization have a medium invasion index and strong colonizers show markedly higher values of this parameter. The characterization of the flagellin gene of the used C. jejuni strains resulted in eight flaA types. There was no association between flaA type and invasion or colonization ability in the chick gut.

Animals↗
PubMed2003

[Identification and differentiation of Campylobacter fetus subspecies by PCR].

The species Campylobacter (C.) fetus is divided into the subspecies venerealis and fetus, which differ in epidemiology and clinical importance. The differences between these subspecies make an accurate distinction essential. Differentiation of C. fetus by traditional microbiological methods is only based on two reactions (tolerance to glycin, Na selenite reduction), in which C. fetus ssp. venerealis reacts negatively. However, the value of both reactions is limited. We used a specific PCR-based assay for identifying and differentiating the two C. fetus subspecies, which was recently developed by HUM et al. (1997). In this assay, a 764 bp amplicon is produced using primers MG3F and MG4R for both subspecies of C. fetus. In contrast to HUM et al. (1997), this amplicon was approximately 200 bp smaller. This discrepancy can't be explained. Afterwards, the primers VenSF and VenSR are used for differentiation. The identification of the sub-species venerealis is based on the presence of a 142 bp amplicon, which is not formed with subspecies fetus. The type strains of both C. fetus subspecies were used as positive controls. Non-specific reactions were not observed. In this PCR assay, 73 field strains were investigated (among them 24 C. fetus ssp. veneralis, 26 C. fetus ssp. fetus). In these investigations, the method has proved its diagnostic suitability. The results of the traditional microbiological differentiation of the C. fetus field strains could be confirmed by the PCR assay. In future, the traditional phenotypic characterization of C. fetus subspecies remains indispensable, but this PCR assay constitutes a valuable method for the confirmation of these results.

Animals↗
PubMed2002

[Colonisation studies using Campylobacter jejuni in chicks].

White Leghorn chicks used in this study were hatched from specific pathogen-free eggs. The colonizing capability of Campylobacter (C.) jejuni strains was investigated in 6 experiments. The formation of specific antibodies associated to colonization was also detected. In each experiment, day of hatch chicks were randomly separated into three groups of 24 birds each: two groups colonized experimentally and one control group. Chicks were reared on the floor in three separated, adjacent rooms with sterilized wood shavings as litter. At 2 or 8 days of age, respectively, the chicks in the experimentally colonized groups received between 3.3 x 10(7) and 2.0 x 10(8) colony-forming units (CFU) of C. jejuni via oesophageal gavage. Furthermore, 7, 14, 21, 28, 42 and 56 days after inoculation, 4 chicks of each group were sacrificed by cervical dislocation, at which time blood, liver and faeces were collected for processing. Serum was centrifuged and Campylobacter-specific IgG, IgA and IgM antibodies were measured by an indirect enzyme-linked immunosorbent assay (ELISA). Altogether, the colonizing capability of 11 C. jejuni strains was examined. Surprisingly, there were large differences between the C. jejuni isolates. After these experiments, we could divide the isolates into three groups. 4 out of 11 isolates could not be reisolated, 2 isolates caused weak or delayed colonization and 5 C. jejuni produced strong, long-lasting colonization. In the first days of life (9 days), the C. jejuni-free SPF chicks (control animals) had high IgG titres in sera, which decreased markedly up to the age of 15 days. During the experiments the IgM and IgA titres remained nearly at the same level, i.e., the amounts of maternal antibodies were low and there was no evidence for antibody formation in the chicks themselves. Two- and 8-day-old chicks were inoculated with C. jejuni strain Penner 1. Two-day-old chicks were colonized 3 weeks after inoculation. In comparison with these animals, 8-day-old chicks were colonized already 2 weeks after inoculation. There is the assumption, that the higher maternal antibodies in 2-day-old chicks could be responsible for this delay. In chicks the C. jejuni colonization resulted in a marked IgG (but not IgM and IgA) increase. Apparently, there is a positive relationship between the counts of this pathogen in caeca and the IgG increase.

Animals↗
PubMed2002

[The use of the toxin binding inhibition test for potency testing of Clostridium novyi type B alpha toxoid vaccines].

The toxin binding inhibition test (ToBI) were developed for potency testing of C. novyi type B alpha toxoid containing veterinary vaccines to replace the currently used toxin neutralisation test in mice (TNT). The antitoxin titres of rabbit sera (AN-, HV- and SP sera) were determined with ToBI using the international reference serum with known antitoxin titre. In order to show the validity of the methods, the results were compared with those of the manufacturers/regulatory authorities and correlation coefficients were calculated. The correlation coefficients were r = 0.93 (AN sera), r = 0.73 (HV sera) and r = 0.85 (SP sera). All correlations were statistically significant. The specificity of the methods could be proved using heterologous antisera. The results of the ToBI were reproducible. Thus, the ToBI offers a suitable in vitro method for the determination of the antitoxin titre of rabbit antisera as an alternative to the toxin neutralisation in mice for potency testing of vaccines containing C. novyi type B alpha toxoid.

Animals↗
PubMed2001

[Development of in vitro methods for the potency testing of clostridial vaccines].

Cell culture assays, using the MDCK cell line was confirmed as being sensitive to the C. perfringens epsilon toxin and VERO cell line to the C. novyi type B alpha toxin. Cell culture assays using these cells were developed and the test conditions were standardised. The antitoxin titres of rabbit antisera were calculated and compared with those of the manufacturers. The correlation coefficients between in vitro and in vivo method were calculated and were significant. The cell culture assay offers a valid in vitro alternative to the animal experiments for the titration of sera generated in the course of potency tests of clostridial vaccines.

Animal Testing Alternatives↗
PubMed2000

Retrocardiac arteriovenous malformation causing recurrent cerebral ischemia.

A 28-year-old woman had been suffering from recurrent cerebral embolizations for almost 9 years. A retrocardiac arteriovenous malformation was identified as the source of emboli. It was supplied by chest wall veins and the right upper pulmonary vein, connected to the back wall of the left atrium and a possibly aberrant hepatic vein originating from the abdomen. The aneurysm was resected and all supplying veins ligated. The vein from below the diaphragm was implanted into the right atrium. Her postoperative course was uncomplicated. Long-term follow-up free from cerebrovascular events.

Adult↗
PubMed1999

Detection of Clostridium novyi type B alpha toxin by cell culture systems.

Ten permanent cell lines were examined for their reaction to the Clostridium novyi alpha toxin. The action of the toxin was determined after 3 days by microscopic examination and the MTT assay. The alpha toxin exhibited the strongest effect on ESH-L cells rather than other cell lines. Vero and SFT-R cells reacted in a comparable way, but less sensitively. We were able to show that the cytopathic effect on the three types of cells was neutralised by the international standard for gas gangrene antitoxin (C. novyi) but in no case by heterologous antisera. Our results have shown that the three cell lines were specific indicators for the detection of the cytopathic effect of alpha toxin. The cytopathic effect can be measured reproducibly by the cell culture assay used. These results are suitable as the starting point for the development of the neutralisation test using cell cultures.

Animals↗
PubMed1998

Simultaneous manifestation of acute myocardial infarction and nephrotic syndrome.

This report describes the simultaneous manifestation of ischemic heart disease and nephrotic syndrome in a 37-year-old woman presenting with acute anterior myocardial infarction. Symptoms of nephrotic syndrome, such as facial and peripheral edema accompanied by proteinuria and hyperlipidemia, and onset of severe retrosternal pain developed within 24 h. Coronary angiography revealed a complete thrombotic occlusion of the proximal portion of the left anterior descending artery with no evidence of arteriosclerotic lesions. Histologic examination of renal biopsy, including electron microscopy, revealed evidence of minimal change glomerulonephritis. Ultrastructural studies demonstrated widespread effacement of epithelial foot processes. Elevated levels of circulating fibrinogen appeared to be an important factor for the hypercoagulable state in this patient, suggesting a causative relationship between coronary thrombosis and nephrotic syndrome.

Adult↗
PubMed1998

Formation of cytotoxins by enteric Campylobacter in humans and animals.

Campylobacter (C.) jejuni from persons suffering from diarrhoea, from organs of poultry, C. jejuni and C. fetus ssp. fetus from the gastrointestinal tract of calves and adult cattle as well as a number of reference strains were examined for cytotoxin formation in a CHO-K1 cell culture test. During evaluation, three morphologically different pictures were observed. The first cytotoxin caused a formation of strikingly large, rounded or polymorphic and elongated cells which was associated with reduced growth. The progressive morphological changes corresponded to those described for the Cytolethal Distending Toxin (CLDT) and were assigned to it. The second cytotoxin produced a rounding of cells without a change in their size while at the same time, growth was reduced. In analogy to CLDT, this toxin was termed Cytolethal Rounding Toxin (CLRT). A third morphological picture consisted of cell changes characterized by enlarged polymorphic as well as by small rounded cells. These cell changes were considered as being distinct from the above mentioned ones and referred to as CLTD/CLRT effect. In none of the 39 Campylobacter strains isolated from humans and calves with diarrhoea, a noteworthy cytotonic activity could be detected that would indicate the presence of an enterotoxin.

Animals↗
PubMed1998

Detection and characterization of two cytotoxins produced by Campylobacter jejuni strains.

Campylobacter jejuni strains are able to produce at least two different cytotoxins called "cytolethal distending toxin" (CLDT) and "cytolethal rounding toxin" (CLRT). In this study, we investigated the corresponding changes in CHO-K1 cells using the cell counter and analyzer system CASY 1. Determination of the cell volume after toxin treatment of the cells is a useful criterion for differentiation between the cytotoxic activities produced by Campylobacter strains. Incubation of the cells with crude CLDT resulted in a decrease in the cell count combined with a dramatic increase of the mean cell volume in comparison to the control culture. A decrease in the cell count was also seen as a response to CLRT preparations, while this toxin had no effect on the mean cell volume determined. It was shown that only CLDT caused histone-associated DNA fragments in the cytoplasm of CHO-K1 cells indicating an apoptotic pathway of cell death. In addition, the polymerase chain reaction (PCR) was employed to screen Campylobacter strains for the presence of the cdtB gene sequence, which was detectable in all strains investigated.

Animals↗
PubMed1998

[Computer assisted training of attention and concentration with healthy children].

The intention of this study was to analyze in how far a computer assisted training for brain damaged adults can be used for the practice with children. Healthy children of different ages were trained with this attention and concentration programme. The results should help to adapt the training programme for the use in brain damaged children. Age-groups differed significantly in level of performance. Data showed that in comparison to Kindergarten-children, first-grade children showed a higher benefit from the training. Implications for modifications of the training-programme are discussed. Other parameter of performance (reaction-time, errors) in relation to school age provide clues to the distribution of structure of difficulty in the programmes. A questionnaire assessing motivation before and during the training, intelligibility of the task, feasibility of the computer and adequacy of the test in children showed that sustained motivation can be achieved provided the training is used in an adaptive way. Thereby demotivating with too easy tasks as well as frustration caused by difficult tasks can be avoided. In general, there was good acceptance of the computerised cognitive training. The presence of a therapist during every training session proved to be necessary in children under the age of 6 years.

Attention↗
PubMed1996

Acute renal failure following cardiac surgery is reverted by administration of Urodilatin (INN: Ularitide).

Acute renal failure (ARF) is a serious complication following cardiac surgery. This first controlled study was undertaken to verify, if Urodilatin (URO) infusion can revert incipient oliguric ARF after cardiac surgery. We conducted a randomized, double blind trial comparing 7 URO (20 ng/kg/min) with 7 placebo patients. Inclusion criterion was oliguria/anuria (< 0.5 ml/kg/hour) refractory to conventional treatment including administration of dopamine and furosemide. No patient in the URO treated group, but 6 patients in the placebo group had to be hemofiltered or hemodialyzed (p < 0.005) during the 7 day treatment period. In the URO group all 7 patients demonstrated a rapid recovery of diuresis after 2 - 8 hours of treatment that persisted throughout the treatment period. In contrast, placebo treated patients remained oliguric. Serum creatinine (SC) decreased in URO treated patients. No adverse effects were observed during URO administration. After termination of URO, 2 patients underwent hemodialysis for elevated blood urea nitrogen (BUN) values. In the postoperative follow-up period of 60 days, 4 out of 7 placebo treated patients died while still on hemodialysis. In contrast, all URO patients survived. URO is an effective drug to reverse oliguric ARF following cardiac surgery. Prolonged renal failure and renal replacement therapy can be avoided.

Acute Kidney Injury↗
PubMed1995

Differential cell count and lymphocyte subsets in bronchoalveolar lavage during pneumonia with and without peripheral neutropenia.

One hundred immunocompromised HIV negative patients with microbiologically positive pneumonia underwent bronchoalveolar lavage (BAL) studies. Thirty cases showed peripheral neutropenia (< 1000 neutrophils/microL), 70 did not. The total cell number in BAL, the differential cell counts, and the lymphocyte subsets (CD4, CD8, CD19, CD57) were measured. Patients with pneumonia and normal or elevated peripheral neutrophils had a significantly increased total number of cells in BAL compared to patients with peripheral neutropenia (3.2 +/- 2 vs 1.3 +/- 0.6 x 10(5) cells/ml2 lavage fluid, p < 0.01). Ninety percent of the BAL differential cell counts obtained in patients exceeding 1000 neutrophils/microL showed a lymphocytic and/or neutrophilic alveolitis, whereas only 54% of patients with peripheral neutropenia displayed abnormal counts (p < 0.01). Yet the typical pattern of neutrophilic alveolitis was found more often for peripheral neutrophil counts over 1000/microL with high significance (p < 0.0001). Abnormal BAL cell patterns for neutropenic patients uniformly showed a lymphocytic alveolitis, only 10% additionally conformed with the pattern of neutrophilic alveolitis. Patients with pneumonia with and without peripheral neutropenia had similar findings in BAL lymphocyte subsets and exhibited a reduced CD4/CD8 ratio compared to controls (p < 0.05). The high susceptibility of severe neutropenic patients to pulmonary, especially fungal infections may be explained by the local lack of neutrophils.

Adolescent↗