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Biomedical subjects

M Hofmann

Publications and source records attributed to M Hofmann.

At least 91 records · Page 5Linked to original sources
PubMed1999

Cell specific effects of glucocorticoid treatment on the NF-kappaBp65/IkappaBalpha system in patients with Crohn's disease.

UNLABELLED: BACKGROUND/AIMS/PATIENTS: Glucocorticoid treatment is known to reduce nuclear factor-kappa B (NF-kappaB)p65 binding activity and activation in lamina propria cells of patients with Crohn's disease. However, lamina propria cells of glucocorticoid treated patients did not show increased expression of IkappaBalpha, and the hypothesised upregulation of IkappaBalpha by glucocorticoid treatment has not yet been shown in vivo. To investigate whether cells other than lamina propria localised mononuclear cells contribute to increased IkappaBalpha, resection gut specimens from patients matched for Crohn's disease activity index (CDAI) with or without glucocorticoid treatment were studied, and changes in the NF-kappaB/IkappaBalpha system were determined in the lamina propria as well as in underlying submucosal and endothelial cells. METHODS: Changes in the NF-kappaB/IkappaBalpha system were determined by immunohistochemistry, electrophoretic mobility shift assay, and western blot analysis in resected gut specimens from patients matched for CDAI and van Hees index with or without long term glucocorticoid treatment. RESULTS: Resection gut specimens from patients with Crohn's disease under glucocorticoid treatment had significantly lower nuclear NF-kappaBp65 levels in mononuclear, epithelial, and endothelial cells than samples from CDAI and van Hees index matched patients not having glucocorticoid treatment. Nuclear NF-kappaBp65 showed a strong positive correlation with both the CDAI (r = 1 for both groups) and the van Hees index (r = 0.605 for untreated and r = 0.866 for glucocorticoid treated specimens). Lower nuclear translocation of NF-kappaBp65 in the glucocorticoid treated group was paralleled by higher IkappaBalpha levels in vascular endothelial cells, but not in infiltrating mononuclear cells. CONCLUSION: A comparison of resection gut specimens from untreated and treated CDAI matched patients with Crohn's disease showed downregulation of NF-kappaB binding activity and NF-kappaBp65 expression and cell specific induction of endothelial IkappaBkappa expression in the glucocorticoid treated group. As the two groups showed similar disease activity (CDAI, van Hees index), the activation of the NF-kappaBp65/IkappaBalpha system must be only part of the inflammatory cascade leading to the clinical appearance of Crohn's disease.

Adult↗
PubMed1999

[Value of p53, urokinase plasminogen activator, PAI-1 and Ki-67 in vulvar carcinoma].

OBJECTIVE: The present study was to measure new prognostic factors including the plasminogen activator urokinase and the plasminogen inhibitor PAI-1, as well as p53 and Ki-67, a marker of proliferation and to compare the clinical value of these in relation to the classic histopathological prognostic factors. MATERIAL AND METHODS: The patient collective included 45 patients with vulvar carcinoma, both primary tumors and recurrences. RESULTS: Highly significant correlations were found for tumor diameter and thickness. According to Kaplan-Meier estimations, the influence of thickness on the prognosis had a p-value of 0.048, while the influence of diameter had a p-value of 0.029. The variable grading was also significantly associated to the probability of survival (p = 0.01). There was no statistically significant correlation between p53 and the parameters grading, degree of keratinization and Ki-67 color index. The correlation between p53 and PAI-1 as well as between UPA and PAI-1 was highly significant. According to the Kaplan-Meier estimations, Ki-67, UPA and PAI-1 had no influence on survival in our group of patients. CONCLUSIONS: For p53, the median value could be used as a divider with the median survival of patients with a p53 below 122 pg/mg protein being 151 months and with a p53 above 122 pg/mg being only 61 months. The corresponding p-value was significant at 0.0201.

Adult↗
PubMed1998

[Multiple endocrine neoplasia associated with multiple lipomas].

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN-1) is characterized by tumors of the parathyroids, the neuroendocrine pancreas-duodenum and the anterior pituitary, but shows also a wide clinical variety of other symptoms. CASE REPORT: We present a case of a 68-year-old woman with a 18 year history of MEN-1 consisting of gastrinoma and primary hyperparathyroidism. Beside these typical symptoms, the patient suffered from thyroid adenoma, malignant kidney tumor and multiple subcutaneous lipomas. RESULT: While the number of autopsies declined from 113 in 1977 to 66 in 1984, the number of diagnostic techniques used increased continuously (94, 107, 118 and 140, amounting to 0.83, 1.34, 1.76 and 2.12 per patient). The premortal detection of abdominal abnormalities increased globally from 16.8 to 32.5%. This increase was largely due to better diagnosis of liver and gallbladder abnormalities which were in most cases of little relevance. CONCLUSION: Whether these non-endocrine tumors are associated to MEN-1 is unclear and has to be tested by examining the chromosomal regions 11q13 and 11q24/25 of the tumors sample, in which the possible MEN-1 involved tumor suppressor genes are located.

Aged↗
PubMed1998

[Reversible dementia].

A 65 year old woman, referred for differential diagnosis of dementia, presented with cognitive and mnestic deficits. Typical signs and symptoms of hypothyroidism led to the diagnosis of severe autoimmune thyroiditis. After six months of treatment with thyroid hormone, dementia, myopathy and ataxia had disappeared. The neurologic and neuropsychologic manifestations of hypothyroidism are discussed. In dementia the diagnosis of secondary and reversible forms is of great importance with regard to prognosis and treatment. Hypothyroidism is known to be a common and treatable cause of pseudodementia. Early diagnosis and adequate treatment are important to prevent further permanent deterioration of cerebral function.

Aged↗
PubMed1998

A novel technology for packing and unpacking pilot and production scale columns.

A new method of packing and unpacking large scale chromatography columns is described. This involves use of a 3-position valve that can inject chromatography media into a closed column thereby packing it. This same valve in another state is then used to unpack the column. Heights equivalent to a theoretical plate and asymmetry factors of packs on columns from 280 to 800 mm diameter are discussed.

Chromatography, Liquid↗
PubMed1998

Self-veto mechanism of CD8+ cytotoxic effector T cells. Peptide-induced paralysis affects the peptide-MHC-recognizing cytotoxic T lymphocytes and is independent of Fas/Fas ligand interactions.

The lytic activity of CD8+ cytotoxic T lymphocyte (CTL) cell lines or clones can be inhibited by addition of the peptide recognized by these cells. The mechanisms underlying this phenomenon are not fully understood. Here we have analyzed peptide-induced CTL paralysis using in vivo generated ovalbumin (OVA)-specific CTL. Lytic activity of OVA-specific CTL was inhibited by addition of the immunodominant OVA-peptide SIINFEKL in a dose-dependent manner. Paralysis was induced rapidly and binding of the peptide to MHC class I molecules was required. Using mixing experiments with CTL populations of different peptide specificities restricted to the same MHC class I molecule we identified a veto-like mechanism: the cytotoxic activity of the peptide-recognizing CTL was inhibited while the lytic activity of the peptide-presenting CTL was unaltered. Only CD8+ CTL but not CD4+ T cells or B+ cells induced paralysis. After removal of the peptide-presenting CTL by magnetic cell sorting, paralysis was maintained and paralyzed CTL showed no signs of apoptosis. Loss of cytotoxicity could be induced in CTL populations from Fas-deficient (lpr+/lpr+) or Fas ligand-deficient (gld+/gld+) mice and mixtures thereof, implying that Fas/Fas ligand interactions are not involved during induction of paralysis. Hence, peptide-induced paralysis of CTL is due to a self-veto mechanism rather than to mutual killing of CTL. These findings may have implications for in vivo immunization with peptides, viral escape and peripheral tolerance mechanisms.

Animals↗
PubMed1998

[Balloon angioplasty of stent restenosis: early and late results of first and second PTCA in focal and diffuse stenosis].

UNLABELLED: From January 1996 until February 1997 6,376 patients were treated by our group with PTCA and 3,859 (60.5%) received one or several stents. An angiographic followup was achieved in 63% of the patients with 1,267 experiencing restenosis (32.8%). Of those being treated with re-PTCA 302 were randomly selected for further analysis. In-stent-restenosis was treated with rotablator in 8 patients (2.7%), with eximer laser in 21 (7.0%) and with another stent in 48 patients (15.9%). 225 patients (74.4%) of this subselection were treated with balloon-angioplasty only. Mean patient age was 63 +/- 10.2 years, 401 stents had been implanted (42.5% Wiktor, 13.7% Jomed Sito, 12.3% ACS Multlink, 9.5% GR II, and some others), the number of stents per patient was 1.68, mean stent length 28.5 mm, mean stent diameter 3.01 +/- 0.3 mm, the time since implantation 142 +/- 76 days. The recurrence appeared as restenosis in 199 patients (88.4%) and as a chronic stent occlusion in 26 (11.6%). In-stent-restenosis was discovered in 94.7% within the stent and was of focal appearance (restenosic lesion of < or = 5 mm) in 28.5% and diffuse (> 5 mm) in 71.5%. Balloondilatation (balloon:artery = 1:1; maximal pressure 11.7 +/- 3.3 bar) was successfull in 98% of the stenotic lesions and in 18/26 of the chronically occluded stents (definition of success: residual stenosis < 50%, no major complications). The stenosis decreased from 82.2% to 20.5% (12.8% in focally stenosed vessels and 23.6% in diffuse restenosis). Complications were death in 0.9%, Q-MI in 0% CABG in 0.9%, Non-Q-MI in 2.4%, subacute stent thrombosis in 0.5% and groin bleeding in 1.8%. A clinical follow up after 151.7 +/- 87.7 days was achieved in 98.6% and an angiographic follow up in 69.1% of the patients: 1.9% had died (2/4 due to noncardiac disease), no MI, 6.2% CABG and 31% PTCA (TLR 37.2%). A second restenosis within the stents ocurred in 27.9% of those with focal disease and in 44.3% of those with diffuse in stent restenosis. CONCLUSIONS: Restenosis within stents may occurr in about 30% of unselected patients. In 2/3 these stenoses appear diffuse and in 10% they appear as chronic occlusions. Re-PTCA with balloons is rather simple with a high success rate (even in chronic stent occlusions) and a low complication rate. The incidence of a second restenosis is acceptably high in focal lesions but appears unacceptable in patients with diffuse in-stent-restenosis. Thus the indication for stenting should be restricted to patients with clear cut advantage over balloon-angioplasty alone, e.g. threatening closure, chronic occlusion, old savenous veingraft and proximal LAD stenosis.

Aged↗
PubMed1998

Effect of the triaminopyridine flupirtine on calcium uptake, membrane potential and ATP synthesis in rat heart mitochondria.

1. Flupirtine is an analgesic agent which exhibits neuronal cytoprotective activity and may have value in the treatment of conditions involving cell injury and apoptosis. Since flupirtine has no action on known receptor sites we have investigated the effect of this drug on mitochondrial membrane potential, and the changes in intramitochondrial calcium concentration in particular. 2. The findings show that flupirtine increases Ca2+ uptake in mitochondria in vitro. At clinically relevant flupirtine concentrations, corresponding to flupirtine levels in vitro of 0.2 to 10 nmol mg(-1) mitochondrial protein, there was a 2 to 3 fold increase in mitochondrial calcium levels (P<0.01). At supra-physiological flupirtine concentrations of 20 nmol mg(-1) mitochondrial protein and above, the mitochondrial calcium concentrations were indistinguishable from those in untreated mitochondria. 3. Mitochondrial membrane potential closely paralleled the changes in mitochondrial calcium levels showing a 20% (P<0.01) increase when the flupirtine concentration was raised from 0.2 nmol to 10 nmol mg(-1) mitochondrial protein and a return to control values at 20 nmol mg(-1) protein. 4. The increase in mitochondrial calcium uptake and membrane potential were accompanied by an increase in mitochondrial ATP synthesis (30%; P<0.05) and a similar percentage reduction in mitochondrial volume. 5. Calcium at 80 and 160 nmol mg(-1) mitochondrial protein decreased ATP synthesis by 20-25% (P<0.001). This decrease was prevented or diminished if flupirtine at 10 nmol mg(-1) protein was added before the addition of calcium. 6. Since intracellular levels of flupirtine in intact cells never exceeded 10 nmol mg(-1) mitochondrial protein, these findings are supportive evidence for an in vivo cytoprotective action of flupirtine at the mitochondrial level.

Adenosine Triphosphate↗
PubMed1998

[Regional distribution of predisposition to maligant hyperthermia in Germany: tate in 1997].

Malignant hyperthermia (MH) is a rare autosomally dominantly hereditary and potentially life-threatening disease. The prevalence of the genetic MH predisposition is estimated as 1:10,000 to 1:20,000. In Germany no data on the regional distribution are available. Therefore, the purpose of this investigation is to summarise and present the epidemiological data of all German MH laboratories. Nine German hospitals offer the specific in vitro contracture test to diagnose the MH predisposition. All German MH laboratories carry out the examination in accordance with the standardised protocol of the European Malignant Hyperthermia Group. The laboratories were asked to provide the number of all patients investigated, excluding those suffering from other neuromuscular diseases, separated according to diagnostic groups and their places of residence, the number of the identified MH-families as well as the number of the clinically suspected and investigated MH cases with their places of residence. Eight MH laboratories provided the requested data. Until September 1997 a total of 2620 patients were investigated. In 865 patients (34%) MH suspicion was confirmed (diagnosis: MHS). 1494 patients (56%) were released by investigation from MH-suspicion (diagnosis: MHN). In 261 patients (10%) the MH-predisposition remained unsolved (diagnosis: MHE). 580 MH families were identified. Among 2620 patients 757 were clinically suspected MH cases. 35% of these suspected MH cases were classified as MHS, 10% as MHE and 55% as MHN. The documentation of the patients places of residence classified as MHS and MHE into a map of Germany demonstrates an exhaustive distribution with an increased regional prevalence in the areas of the MH laboratories. This concentration in the area of the MH laboratories becomes even more evident, when the places of residence of the MH suspected cases are demonstrated. In conclusion, the distribution of the MH predisposition is uniform and exhaustive in Germany. The presented regional concentration of clinically suspected MH cases among the MH laboratories is mainly interpreted as an expression of effective regional education and information. Considering the overall incidence of the MH predisposition as described above only 15-20% of the MH patients have so far been identified. The MH laboratories have already released about 10,000 patients from the suspicion of MH predisposition. A preliminary prevalence of at least 1:60,000 to 1:80,000 in Germany can be estimated according to the presented data.

Epidemiologic Studies↗
PubMed1998

C-myc mRNA expression in epithelial ovarian carcinomas in relation to estrogen receptor status, metastatic spread, survival time, FIGO stage, and histologic grade and type.

Recently, it has been suggested that c-myc expression might correlate with estrogen receptor (ER) status and metastatic spread in ovarian cancer. In this study, expression of c-myc mRNA in 90 epithelial ovarian carcinomas was determined using the S1 nuclease protection assay. Expression of c-myc mRNA was detectable in 27 of 90 tumors. There was no significant association between c-myc mRNA expression and metastatic spread, survival time, FIGO stage, or histologic grade and type. C-myc mRNA was expressed in 45% of ER-positive tumors but only 24% of ER-negative tumors (p = 0.094; Fisher's exact test). Similarly, 44% of progesterone receptor (PR)-positive and 23% of PR-negative tumors expressed c-myc mRNA (p = 0.098). However, the association between c-myc mRNA expression and ER and PR status was not statistically significant. The ratio of mean expression of c-myc mRNA in patients with FIGO stages III/IV compared with patients with FIGO stages I/II was 2.1:1, an insignificant difference (p = 0.57, Wilcoxon rank sum test). In conclusion, c-myc was not significantly associated with the clinical parameters investigated in this study.

Carcinoma↗
PubMed1998

Identification of IHABP, a 95 kDa intracellular hyaluronate binding protein.

The extracellular matrix component hyaluronan is believed to play important roles in various processes of organogenesis, cell migration and cancer. Recognition of and binding to hyaluronan is mediated by cell surface receptors. Three of them, CD44, ICAM-1 and RHAMM (receptor for hyaluronic acid mediated motility), have been identified. A cDNA clone designated RHAMM turned out to possess transforming capacity. Based on this published sequence, we isolated the complete cDNA of the murine gene. The cDNA comprises an open reading frame of 2.3 kb and encodes a 95 kDa protein. The protein carries a hyaluronan binding motif which binds to hyaluronan in vitro but not to heparin or chondroitin sulphate. It is ubiquitously expressed in normal cells and in all tumour cell lines irrespective of their metastatic properties. One tumour cell line, the metastatic Lewis lung carcinoma, expresses a larger 105 kDa variant form of the protein due to a genomic rearrangement. Antibodies raised against the 95 kDa protein were used for subcellular localization studies. The hyaluronan binding protein is not detectable at the cell surface but is rather localized exclusively intracellularly. Clearly, the sequence we have identified encodes a protein with properties substantially different to the RHAMM protein. We tentatively name the protein intracellular hyaluronic acid binding protein, IHABP.

3T3 Cells↗
PubMed1998

The human hyaluronan receptor RHAMM is expressed as an intracellular protein in breast cancer cells.

The receptor for hyaluronan mediated motility (RHAMM) has been reported to mediate migration, transformation, and metastatic spread of murine fibroblasts. Here we describe the expression of two human RHAMM isoforms, which are generated by alternative splicing of the primary gene transcript, by a series of human breast carcinoma cell lines. A polyclonal antibody, raised against a bacterially expressed RHAMM fusion protein, detected an 85-90 kDa protein by western blot analysis. No correlation between the level of RHAMM mRNA and protein expression with known metastatic/malignant potential of the tumour cell lines was observed. Interestingly, we found that the antibody did not stain the cell surface but the cytoplasm of breast cancer cells. The intracellular localisation of RHAMM was confirmed by subcellular fractionation studies. RHAMM proteins were capable of binding to hyaluronan, but not to heparin or chondroitin sulphate, in an vitro binding assay. We also provide evidence that a potential hyaluronan-binding motif in the N terminus of the protein is not involved in the interaction of RHAMM with hyaluronan. Our findings lead us to conclude that RHAMM does not function as a conventional motility receptor for HA in human breast cancer cells and we suggest the term RHAMM be substituted by 'intracellular hyaluronic acid binding protein' (IHABP).

Alternative Splicing↗
PubMed1998

Theronts of Ichthyophthirius multifiliis find their fish hosts with complex behavior patterns and in response to different chemical signals.

How parasites find and recognize fish hosts is best known for trematode cercariae. These multicellular organisms respond with complex behavior patterns to sequences of different chemical host signals, although these invasive stages are produced in large numbers. However, little is known on the host-finding of protozoan parasites. We therefore studied how the infective theronts of I. multifiliis find their fish hosts by offering them various fractions and chemical modifications of fish skin surface. Free swimming theronts showed at least 6 different behavior patterns, 4 of them were stimulated by fish skin components, e.g. by amino acids. Theronts approached towards solid substrates ("stop and go ahead") in response to macromolecular glycoproteins of fish skin, and they were repelled ("stop and turn away") by other macromolecular glycoconjugates. After contact with solid surfaces, they repeatedly dipped on the surface ("dipping contact") in response to glycoconjugates of fish skin and they swam along the surface ("body parallel") when it contained proteins of fish skin. The results demonstrate that also a protozoan fish-parasite without nervous system and cellular chemoreceptors may show very diverse host-finding behavior patterns (at least 11) and may respond to different chemical host cues (at least 5).

Amino Acids↗