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Biomedical subjects

S Siegert

Publications and source records attributed to S Siegert.

10 recordsLinked to original sources
PubMed2003

[Hepatitis of unknown origin with protracted liver failure in a 48-year-old patient with significantly increased pANCA titer].

In spite of intense diagnostic testing, no cause for the chronically aggressive hepatitis of a 48-year old male patient was found. Evidence for an autoimmune process, however, could be derived from a high titer of pANCA. Only according to the revised criteria of the working group on autoimmune hepatitis, but not to the first version, it was possible to classify this as an autoimmune hepatitis. Despite of high-dose steroid treatment and accelerated preparation for liver transplantation the patient died of the complications of rapid liver failure. Thus, in case of unclear rapid progressive hepatitis, the revised criteria of autoimmune hepatitis should be reviewed early and with high priority and consequent high-dose steroid therapy and preparation for liver transplantation should be initiated. The prognostic impact of a high titer of pANCA in patients with autoimmune hepatitis remains to be established.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2001

Modeling of nonlinear Lévy processes by data analysis.

The paper presents a method to analyze time series of nonlinear Lévy processes. The Lévy stability index as well as the nonlinear deterministic and stochastic parts of the dynamics together with their uncertainties can be calculated numerically. As last step of the analysis the membership of the investigated system to the regarded class of dynamical systems is validated. For demonstration the algorithm is applied to artificially created time series with different Lévy indices.

Journal Article↗
PubMed2001

Hyponatraemia as a complication of colonoscopy.

A case of colonoscopy-induced hyponatraemic encephalopathy led us to study the risk of hyponatraemia after gastrointestinal endoscopy. We assessed 40 patients before and after colonoscopy. 20 gastroscopy patients served as controls. Our findings show a high incidence (7.5%) of hyponatraemia after colonoscopy, in association with raised serum concentrations of arginine vasopressin. Physicians should be aware of this complication, since it may contribute to psychological and neurological symptoms after colonoscopy.

Arginine Vasopressin↗
PubMed2001

Low T cell production of TNFalpha and IFNgamma in ankylosing spondylitis: its relation to HLA-B27 and influence of the TNF-308 gene polymorphism.

OBJECTIVE: To test the hypothesis that ankylosing spondylitis (AS) is a T helper cell type 2 polarised disease by quantifying the T cell cytokines interferon gamma (IFNgamma), interleukin 4 (IL4), tumour necrosis factor alpha (TNFalpha), and IL10 at the single cell level in patients with AS in comparison with healthy HLA-B27 negative and HLA-B27 positive controls. METHODS: Peripheral blood mononuclear cells from 65 subjects (25 HLA-B27 positive patients with active AS, 18 healthy HLA-B27 positive controls, and 22 healthy HLA-B27 negative controls) were stimulated with phorbol myristate acetate/ionomycin for six hours, surface stained for CD3 and CD8, intracellularly stained for the cytokines IFNgamma, TNFalpha, IL4, and IL10, and analysed by flow cytometry. TNFalpha production was related to the genotype of the TNFalpha promoter at the -308 and -238 polymorphisms. RESULTS: In peripheral blood the percentage of TNFalpha+ T cells was significantly lower in HLA-B27 positive patients with AS (median 5.1% for CD4+ T cells) than in healthy HLA-B27 negative controls (median 9.5%; p=0.008). Surprisingly, the percentage of TNFalpha+ T cells was also significantly lower in healthy HLA-B27 positive controls (median 7.48%) than in healthy HLA-B27 negative controls (p=0.034). Furthermore, the percentage of IFNgamma+ T cells was lower in patients with AS and in healthy HLA-B27 positive controls than in healthy HLA-B27 negative controls (p=0.005 and p=0.003, respectively). The percentage of IL10+/CD8+ T cells was higher in patients with AS than in both control groups. In HLA-B27 positive subjects, TNF1/2 heterozygosity at -308 (n=6) was associated with a higher percentage of TNFalpha+ T cells than TNF1/1 homozygosity (n=25; median 9.97% v 5.11% for CD4+ T cells; p=0.017). In contrast, in HLA-B27 negative controls (n=18) there was no such genotype/phenotype correlation (median 9.4% v 10.6%). CONCLUSIONS: The lower T cell production of TNFalpha and IFNgamma shown at the single cell level in HLA-B27 positive patients with AS and healthy HLA-B27 positive controls may contribute to the increased susceptibility of HLA-B27 positive subjects to develop AS. Preliminary genotype-phenotype correlations suggest that in HLA-B27 positive subjects TNF2 at -308 or a linked gene results in higher TNFalpha production and, therefore, might be a marker for a protective haplotype.

Adult↗
PubMed2000

Analysis of time series from stochastic processes

Analysis of time series from stochastic processes governed by a Langevin equation is discussed. Several applications for the analysis are proposed based on estimates of drift and diffusion coefficients of the Fokker-Planck equation. The coefficients are estimated directly from a time series. The applications are illustrated by examples employing various synthetic time series and experimental time series from metal cutting.

Journal Article↗
PubMed2000

Response to methotrexate in early rheumatoid arthritis is associated with a decrease of T cell derived tumour necrosis factor alpha, increase of interleukin 10, and predicted by the initial concentration of interleukin 4.

OBJECTIVE: This study was performed to assess whether there is any change in the T cell cytokine pattern in early rheumatoid arthritis (RA) patients treated with methotrexate (MTX) and whether the lymphocytic cytokine pattern correlates with disease activity. METHODS: Eight patients with RA (disease duration < six months) were studied serially before, after three, and after six to nine months of treatment with MTX for the cytokines tumour necrosis factor alpha (TNFalpha), interferon gamma (IFNgamma), interleukin 4 (IL4) and interleukin 10 (IL10) by intracellular staining of T cells derived from peripheral blood. Response to treatment was assessed by the modified disease activitiy score. RESULTS: The clincial response was accompanied by a significant decrease of TNFalpha positive CD4(+) T cells from a median of 8.53% (interquartile range 5.83-10.91%) before treatment to 6.17% (2.15-6.81%) after six to nine months of treatment (p=0.021). Inversely, IL10 positive T cells increased from a median of 0.65% (interquartile range 0.6-0.93%) to a median of 1. 3% (1.22%-1.58%) after six to nine months of treatment (p=0.009). No significant change in the percentage of INFgamma positive T cells and a small decrease of IL4 positive T cells during treatment were observed. The percentage of IL4 positive CD4(+) T cells before treatment correlated with disease activity after six to nine months (r= -0.7066; p=0.05). CONCLUSIONS: During treatment of RA with MTX the percentage of TNFalpha producing T cells decreases whereas that of IL10 producing T cells increases. This may affect macrophage activation and, therefore, may represent a regulatory mechanism relevant to disease remission. Furthermore, the percentage of IL4 positive CD4(+) T cells at disease onset may be a useful prognostic marker.

Antirheumatic Agents↗
PubMed1999

Low secretion of tumor necrosis factor alpha, but no other Th1 or Th2 cytokines, by peripheral blood mononuclear cells correlates with chronicity in reactive arthritis.

OBJECTIVE: To determine Th1 and Th2 cytokine production in patients with reactive arthritis (ReA) in relation to disease outcome and in comparison with rheumatoid arthritis (RA). METHODS: Secretion of tumor necrosis factor alpha (TNFalpha), interferon-gamma, interleukin-10 (IL-10), and IL-4 by peripheral blood mononuclear cells (PBMC) from 53 patients with early ReA (disease duration <8 weeks, 64% HLA-B27 positive) and 30 patients with early, untreated RA (disease duration <6 months) was determined by enzyme-linked immunosorbent assay (ELISA) after ex vivo stimulation. Intracellular cytokine staining with quantification of positive T cells by fluorescence-activated cell sorting (FACS) was performed in 12 ReA patients and 12 RA patients. In 27 ReA patients, cytokine secretion was measured again after 3 months. Patients were followed up for 1 year, and cytokine patterns were correlated with disease duration. RESULTS: TNFalpha secreted by whole PBMC and by T cells was significantly lower, by ELISA and by FACS, in ReA patients than in RA patients, while no significant differences were detected for the other cytokines. ReA patients with a disease duration of > or =6 months showed significantly lower TNFalpha secretion than patients with a disease duration of <6 months (mean +/- SD 385 +/- 207 pg/ml versus 684 +/- 277 pg/ml; P = 0.003). Furthermore, low TNFalpha secretion after 3 months also correlated significantly with a more chronic course of disease. HLA-B27 positive patients secreted less TNFalpha than did those who were B27 negative (338 +/- 214 pg/ml versus 512 +/- 207 pg/ml; P = 0.05), and patients with a more chronic course had a higher frequency of B27 positivity (47% versus 80%; P = 0.01). Among the 27 HLA-B27 positive patients, TNFalpha secretion in those with a disease duration of > or = 6 months was lower than that in the 7 with a disease duration of <6 months (308 +/- 167 pg/ml versus 562 +/- 308 pg/ml; P = 0.04). CONCLUSION: Low TNFalpha secretion and HLA-B27 status correlate with longer disease duration in ReA patients, possibly with an additive effect. The diminished TNFalpha production might reflect a state of relative immunodeficiency contributing to bacterial persistence in ReA.

Adult↗
PubMed1999

The elevated ratio of interferon gamma-/interleukin-4-positive T cells found in synovial fluid and synovial membrane of rheumatoid arthritis patients can be changed by interleukin-4 but not by interleukin-10 or transforming growth factor beta.

OBJECTIVES: To quantify the T-helper type (Th) 1 cytokine interferon gamma (IFN-gamma)-positive and the Th2 cytokine interleukin (IL)-4-positive cells in synovial fluid (SF) and synovial membrane (SM) at the single-cell level in rheumatoid arthritis (RA) in comparison to reactive arthritis (ReA), and to manipulate the cytokine pattern of RA patients in vitro. METHODS: Eighteen patients with RA and 17 with ReA were studied. For intracellular staining of cytokines, SF mononuclear cells (MNC) from seven patients with RA, in comparison to eight patients with ReA, were triple stained with anti-IFN-gamma, IL-4 and anti-CD4 or anti-CD8 monoclonal antibodies (mAb) and analysed by flow cytometry. Furthermore, in 13 patients with RA, immunohistology of SM was performed and compared with seven ReA patients. In addition, in six of the RA patients, synovial T cells were grown over 3 weeks in the presence of various cytokines and intracellular cytokine staining analysed by flow cytometry weekly. RESULTS: In SF, the mean percentage of IFN-gamma+/CD4+ T cells in RA was almost 4-fold higher than the number of IL-4+/CD4+ T cells (11.3+/-5 vs 3.02+/-1.04; P=0.0012), while the ratio of IFN-gamma/IL-4+ CD4+ T cells was only 1.59 in ReA (P=0.047 for the ratio difference). A similar result was obtained for SM: the ratio of IFN-gamma/IL-4+ cells in RA was 4.3 (P<0.0001 for the IFN-gamma/IL-4 difference), but only 1.2 for ReA (P=0.02 for the ratio difference). Of the CD3+ cells in SM, 2.8% were positive for IFN-gamma and 0.4% for IL-4 in three RA patients. A decrease in the number of IFN-gamma-positive SF T cells and an increase in the number of IL-4-positive SF T cells could be achieved in vitro through IL-4, but not by IL-10 or transforming growth factor beta. CONCLUSIONS: The Th1 pattern in the joint of RA patients demonstrated at the single-cell level may be important for the pathogenesis of RA and may provide a target for future immunotherapy. Our data suggest a therapeutic role for IL-4.

Adolescent↗
PubMed1997

Interphase cytogenetic analysis of mucinous ovarian neoplasms.

Extending our previous efforts to characterize ovarian neoplasms by interphase cytogenetics, we analyzed a series of 32 mucinous tumors by nonisotopic in situ hybridization with seven different centromere-specific probes as well as by flow and image DNA cytometry; we then compared the data with results of p53 and Ki67 immunohistochemistry and MYC DNA-PCR analysis and of the clinical follow-ups. Of the tumors studied, 11 of 14 (78.6%) mucinous carcinomas, 7 of 7 (100%) mucinous tumors of low malignant potential (LMP), and 7 of 11 (63.6%) mucinous cystadenomas demonstrated chromosomal aberrations. The mean number of chromosomal aberrations (+/- SD) was slightly higher in DNA cytometrically nondiploid cases than in diploid cases (2.0 +/- 1.6 versus 1.6 +/- 1.2, not significant) but did not differ significantly among the study groups (carcinomas: 1.7 +/- 1.4; tumors of LMP; 1.9 +/- 0.7; adenomas: 1.4 +/- 1.4). Aberrations affected chromosomes 1 (14 of 27 cases) and 6 (12 of 31) most frequently, followed by chromosomes 17 (7 of 28), 7 (6 of 29), and X (6 of 28). Signal gain for centromere 1, which was the most prevalent finding (13 of 27), was observed in 3 of 10 mucinous cystadenomas, 2 of 4 mucinous tumors of LMP, and 8 of 13 mucinous carcinomas. All six moderately and poorly differentiated carcinomas demonstrated this aberration. Signal gain of centromere 6 (3 of 13) and centromere 7 (4 of 13) were found only in carcinomas (p < 0.05 and p < 0.025, respectively). The interphase cytogenetic results correlated neither with proliferative activity, immunohistochemical p53 accumulation, MYC DNA amplification, nor postoperative outcome. Compared with serous ovarian neoplasms (Lab Invest 1996, 75:473-485), mucinous tumors demonstrated signal gain for chromosome 1 (p < 0.0001) and signal loss for chromosomes 6 (p < 0.001) and X (p < 0.01) significantly more often. Loss of centromere 17 was more characteristic for serous than for mucinous carcinomas (p < 0.05). Our observations show that chromosomal aberrations in mucinous ovarian neoplasms are apparently not random. These results support the notion that the molecular genetic changes in mucinous neoplasms differ from those in serous tumors.

Adenocarcinoma, Mucinous↗