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S Herrmann

Publications and source records attributed to S Herrmann.

At least 37 records · Page 2Linked to original sources
PubMed1997

Evaluation of Y-chromosomal STRs: a multicenter study.

A multicenter study has been carried out to characterize 13 polymorphic short tandem repeat (STR) systems located on the male specific part of the human Y chromosome (DYS19, DYS288, DYS385, DYS388, DYS389I/II, DYS390, DYS391, DYS392, DYS393, YCAI, YCAII, YCAIII, DXYS156Y). Amplification parameters and electrophoresis protocols including multiplex approaches were compiled. The typing of non-recombining Y loci with uniparental inheritance requires special attention to population substructuring due to prevalent male lineages. To assess the extent of these subheterogeneities up to 3825 unrelated males were typed in up to 48 population samples for the respective loci. A consistent repeat based nomenclature for most of the loci has been introduced. Moreover we have estimated the average mutation rate for DYS19 in 626 confirmed fatherson pairs as 3.2 x 10(-3) (95% confidence interval limits of 0.00041-0.00677), a value which can also be expected for other Y-STR loci with similar repeat structure. Recommendations are given for the forensic application of a basic set of 7 STRs (DYS19, DYS3891, DYS389II, DYS390, DYS391, DYS392, DYS393) for standard Y-haplotyping in forensic and paternity casework. We recommend further the inclusion of the highly polymorphic bilocal Y-STRs DYS385, YCAII, YCAIII for a nearly complete individualisation of almost any given unrelated male individual. Together, these results suggest that Y-STR loci are useful markers to identify males and male lineages in forensic practice.

DNA Mutational Analysis↗
PubMed1997

Chromosome Y microsatellites: population genetic and evolutionary aspects.

By means of a multicenter study, a large number of males have been characterized for Y-chromosome specific short tandem repeats (STRs) or microsatellites. A complete summary of the allele frequency distributions for these Y-STRs is presented in the Appendix. This manuscript describes in more detail some of the population genetic and evolutionary aspects for a restricted set of seven chromosome Y STRs in a selected number of population samples. For all the chromosome Y STRs markedly different region-specific allele frequency distributions were observed, also when closely related populations were compared. Haplotype analyses using AMOVA showed that when four different European male groups (Germans, Dutch, Swiss, Italians) were compared, less than 10% of the total genetic variability was due to differences between these populations. Nevertheless, these pairwise comparisons revealed significant differences between most population pairs. Assuming a step-wise mutation model and a mutation frequency of 0.21%, it was estimated that chromosome Y STR-based evolutionary lines of descent can be reliably inferred over a time-span of only 1950 generations (or about 49,000 years). This reduces the reliability of the inference of population affinities to a historical, rather than evolutionary time scale. This is best illustrated by the construction of a human evolutionary tree based on chromosome Y STRs in which most of the branches connect in a markedly different way compared with trees based on classical protein polymorphisms and/or mtDNA sequence variation. Thus, the chromosome Y STRs seem to be very useful in comparing closely related populations which cannot probably be separated by e.g. autosomal STRs. However, in order to be used in an evolutionary context they need to be combined with more stable Y-polymorphisms e.g. base-substitutions.

Biological Evolution↗
PubMed1997

Infections with Pseudomonas aeruginosa in patients with cystic fibrosis.

The lung infection with Pseudomonas aeruginosa is regarded as one of the major causes of health decline in patients with cystic fibrosis (CF). The CF host response to the persistent bacterial antigen load in the endobronchiolar lumen is characterized by a pronounced humoral response, local production of cytokines, influx of neutrophils into the lung and a protease-protease inhibitor imbalance predominantly sustained by released neutrophil elastase. CF is an autosomal recessive disease, and we could demonstrate for our local patient population that the age-dependent risk to become chronically colonized with P. aeruginosa can be differentiated by the disease-causing CFTR mutation genotype. The age-specific colonisation rates were significantly lower in pancreas sufficient than in pancreas insufficient patients. P. aeruginosa is occasionally detected in throat swabs already in infancy or early childhood in most patients although there is a lapse of several years amenable to preventive measures such as vaccination until onset of persistent colonization. The epidemiology of the infection with P. aeruginosa was investigated by quantitative macrorestriction fragment pattern analysis. The distribution and frequency of clones found in CF patients match that found in other clinical and environmental aquatic habitats, but the over-representation of specific clones at a CF clinic indicates a significant impact of nosocomial transmission for the prevalence of P. aeruginosa-positive patients at a particular center. Most patients remain colonized with the initially acquired P. aeruginosa clone. According to direct sputum analysis the majority of patients is carrying a single clonal variant at a concentration of 10(7)-10(9) CFU. Co-colonization with other species or other clones is infrequent. Independent of the underlying genotype, the CF lung habitat triggers a uniform, genetically fixed conversion of bacterial phenotype. Most CFP, aeruginosa strains become non-motile, mucoid, LPS-, pyocin- and phage-deficient, secrete less virulence determinants and shift the production of cytokines evoked in neutrophils. On the other hand, other properties such as antimicrobial susceptibility or adherence to bronchial mucins remain highly variable reflecting the capacity of P. aeruginosa to adapt to ongoing changes in the CF lung habitat.

Cystic Fibrosis↗
PubMed1996

Rescue of hybrid sterility in crosses between D. melanogaster and D. simulans.

The genetic analysis of reproductive isolation between species of Drosophila has now reached the resolution necessary to start answering one of the fundamental questions of evolution: what is the genetic basis of species differences? A.H. Sturtevant, one of the founders of Drosophila genetics, was fascinated by this question and thought he had found a way to analyse it when he realized that 'Drosophila melanogaster' was actually two species: D. melanogaster and D. simulans. By passing genes between these two species he hoped to investigate their genetic differences directly. No doubt he was disappointed to find that the D. melanogaster/D. simulans hybridization resulted only in unisexual sterile hybrids, a disappointment appreciated all the more by modern evolutionary biologists. Seventy-five years after Sturtevant's description of D. melanogaster/D. simulans hybrid sterility, we have discovered a strain of D. simulans that produces fertile female hybrids in crosses with D. melanogaster. Our discovery promises to bring the enormous resolution of D. melanogaster genetics to the study of reproductive isolation and species differences.

Animals↗
PubMed1996

Phenprocoumon for prevention of shunt occlusion after transjugular intrahepatic portosystemic stent shunt: a randomized trial.

Development of stenosis or occlusion of the transjugular intrahepatic portosystemic stent shunt (TIPSS) is one of the major limiting factors in the long-term viability of this procedure. The efficacy of anticoagulation with heparin which is used in different centers is still unclear. In the present study, we evaluated the effect of phenprocoumon on shunt patency after TIPSS placement using Palmaz stents; 49 patients with Child's A and B cirrhosis, who underwent successful TIPSS placement were randomized into the treatment group (n = 24) who received phenprocoumon and a control group (n = 25). After 11 to 13 weeks, all patients were admitted and had a reevaluation that included control angiography by transjugular approach. Phenprocoumon treatment was stopped after the first reevaluation and both groups were followed for 1 year after randomization. During the 3-month treatment period 11 of 22 patients of the treatment group and 12 of 23 patients of the control group required reintervention because of an increased portosystemic gradient. Five of the 12 patients in the control group showed complete occlusion of the shunt, whereas no occlusion in the treatment group was observed (P < .05). During the mean follow-up of 8 months after the treatment was stopped, in both groups stenosis occurred in 50% of patients, but no further occlusion of the stent was observed. These data indicate that occlusion of the stent is related to thrombosis, whereas stenosis does not appear to be dependent on blood coagulation. In patients with preserved liver function occlusion of the shunt may be prevented by phenprocoumon treatment in the first 3 months after TIPSS placement. Thereafter shunt occlusion was not observed and further phenprocoumon treatment seemed unnecessary.

Anticoagulants↗
PubMed1996

Molecular mechanisms underlying IFN-gamma-mediated tumor growth inhibition induced during tumor immunotherapy with rIL-12.

The present study investigates the molecular mechanisms by which IFN-gamma produced as a result of in vivo IL-12 administration exerts its anti-tumor effects. rIL-12 was administered three or five times into mice bearing CSA1M fibrosarcoma, OV-HM ovarian carcinoma or MCH-1-A1 fibrosarcoma. This regimen induced complete regression of CSA1M and OV-HM tumors but only transient growth inhibition of MCH-1-A1 tumors. The anti-tumor effects of IL-12 were associated with enhanced induction of IFN-gamma because these effects were abrogated by pretreatment of hosts with anti-IFN-gamma antibody. Exposure in vitro of the three types of tumor cells to rRFN-gamma resulted in moderate to potent inhibition of tumor cell growth. IFN-gamma stimulated the expression of mRNAs for an inducible type of NO synthase (iNOS) in CSA1M cells and indoleamine 2,3-dioxygenase (IDO), an enzyme capable of degrading tryptophan, in OH-HM cells, but induced only marginal levels of these mRNAs in MCH-1-A1 cells. In association with iNOS gene expression, IFN-gamma-stimulated CSA1M cells produced a large amount of NO which functioned to inhibit their own growth in vitro. Although OV-HM and MCH-1A1 cells did not produce NO, they also exhibited NO susceptibility. Whereas the tumor masses from IL-12-treated CSA1M-bearing or OV-HM-bearing mice induced higher levels of iNOS (for CSA1M) or IDO and iNOS (for OV-HM) mRNAs, the MCH-1-A1 tumor mass expressed lower levels of iNOS mRNA alone. Moreover, massive infiltration of CD4(+) and CD8(+) T cells and Mac-1(+) cells was seen only in the CSA1M and OV-HM tumors. Thus, these results indicate that IFN-gamma produced after IL-12 treatment induces the expression of various genes with potential to modulate tumor cell growth by acting directly on tumor cells or stimulating tumor-infiltrating lymphoid cells and that the effectiveness of IL-12 therapy is associated with the operation of these mechanisms.

Animals↗
PubMed1995

Administration of recombinant interleukin 12 prevents outgrowth of tumor cells metastasizing spontaneously to lung and lymph nodes.

The present study investigates the ability of recombinant interleukin 12 (rIL-12) to modulate the growth of a primary tumor as well as the outgrowth of metastatic tumor cells in an ovarian carcinoma (OV-HM) model. This aggressive tumor displayed rapid growth of the primary tumor mass, high incidence of metastases to lung and lymph nodes, and invasion from the primary s.c. site to the peritoneal cavity. Starting 12 days after s.c. tumor cell implantation, several i.p. injections of rIL-12 at 2-3 day intervals resulted in regression of growing tumors. These treated mice did not show signs of metastases or tumor recurrence at the original site. One month after tumor implantation, untreated mice did not have visible lung metastasis, but some did have palpable lymph nodes. At this stage, the primary tumors of animals without palpable lymph nodes were surgically resected. When examined 2 months later, most animals had developed lymph node and lung metastases. In contrast, rIL-12 injections after tumor resection inhibited the development of metastases in both lung and lymph nodes. This contrasted with the failure of IL-2 to prevent metastases. Even for mice already showing signs of lymph node metastases or invasion of the abdominal wall, rIL-12 administration after tumor resection prevented further invasion to the peritoneal cavity and growth of metastatic tumor cells in lung. It was somewhat surprising that the IL-12 treatment of animals after 1 month of tumor growth without resection also resulted in complete tumor regression, as well as eradication of micrometastasis that would have occurred before the treatment. Moreover, they exhibited resistance to a rechallenge with the same tumor but not with a second tumor. Thus, this tumor system provides a relevant model to clinical situations in terms of treatment of advanced tumors and metastases. These results also indicate that IL-12 can induce a curative immune response, even in the face of an aggressive micrometastasizing tumor.

Animals↗
PubMed1995

[Acute liver failure as the initial manifestation of Wilson disease].

BACKGROUND: Establishing an early diagnosis is crucial to successfully treat mostly young patients with sudden onset acute hepatic failure as the initial symptom of Wilson's disease. Recognition of the entity of Wilsonian fulminant hepatitis is important, because liver transplantation improves survival if performed in a timely fashion. METHODS: Retrospective case analysis regarding characteristic profile of standard laboratory parameters and clinical course of acute Wilsonian hepatic failure. RESULTS: In two female patients (age 17 and 27 years) with non-autoimmune hemolysis serum AST and ALT levels were only moderately elevated with a conspicuously diminished ALT activity and relatively low serum alkaline phosphatase (AP) levels. Despite immediate application of D-Penicillamin one patient died from complications of multiorgan failure. CONCLUSION: In fulminant Wilsonian hepatic failure the AP/bilirubin ratio is usually below 2. Additionally calculation of free copper concentration in serum and renal excretion of ionic copper in combination with non-autoimmune hemolysis provide clues to establish an early diagnosis of Wilsonian hepatic failure.

Adolescent↗
PubMed1994

IL-12 protects bone marrow from and sensitizes intestinal tract to ionizing radiation.

IL-12, a potent stimulator of hemopoietic progenitor cells, was evaluated as a potential protector against 60Co-gamma radiation-induced lethal hemopoietic syndrome in mice. Administration of IL-12 before lethal irradiation of genetically distinct strains of mice, B6D2F1 and C3H/HeJ, protected a significant fraction of both strains of mice from death. Radioprotection was associated with a fivefold increase in the number of bone marrow cells at 6 days after irradiation. Even at supralethal doses of radiation (1200 cGy), the number of c-kit+ bone marrow cells 3 days after irradiation was twofold greater in IL-12-treated mice than in saline-treated mice. However, mice that received IL-12 and 1200 cGy (B6D2F1) or 900 cGy (C3H/HeJ) died of the gastrointestinal syndrome, as was evident by gross necroscopy and histologic evaluation, within 4 to 6 days after irradiation. Induction of the gastrointestinal syndrome in mice not treated with IL-12 required radiation doses of 1500 cGy or greater in both strains. Thus, at doses of radiation at which IL-12 still protects c-kit+ hemopoietic cells, it sensitizes the intestinal tract to damage. Radioprotection with IL-12 was abrogated by anti-IL-1R or anti-stem cell factor Ab. Anti-IFN-gamma Ab did not affect IL-12-induced hemopoietic radioprotection, but abrogated sensitization of the intestinal tract by IL-12. The sensitizing effect of IL-12 may be related to its ability to prime mice to subsequent inflammatory challenge, as demonstrated by an almost 100-fold increase in circulating TNF and IL-6 levels in normal B6D2F1 mice challenged with IL-12 and LPS. This priming effect of IL-12 also was abrogated by anti-IFN-gamma Ab.

Animals↗
PubMed1994

The prognostic value of magnetic resonance imaging for the management of breech delivery.

In patients with breech presentation secondary cesarean section is often caused by a failure to progress in labor due to a disproportion between fetal breech and maternal pelvis. The aim of the present study was to select such patients for primary cesarean section by prenatal use of magnetic resonance imaging. In 39 patients with breech presentation at term, maternal obstetric conjugate, transversal inlet diameter, sagittal mid-pelvis diameter, and interspinal distance, as well as fetal transversal and sagittal breech diameters, were measured by magnetic resonance imaging 1-7 days before delivery. All obstetricians that were involved in this study were blind to the measured values. For statistical evaluation the Mann-Whitney U-test was used. In 13 of these patients a secondary cesarean section was performed due to failure to progress in labor and in 9 due to other indications (intrauterine asphyxia, etc.). Seventeen women were delivered vaginally. The proportion between maternal pelvic inlet and fetal breech diameters was significantly less favourable in patients with failure to progress in labor (n = 13) than that in patients who were delivered vaginally (n = 17) (0.97 +/- 0.06 vs. 0.86 +/- 0.05, P < 0.001). Furthermore, by comparing the maternal pelvic inlet diameters with the corresponding fetal breech diameters, three groups of patients could be selected: one group (A; n = 8), in which the patients could be delivered only by cesarean section, a second group (B; n = 10), in which delivery by both cesarean section and vaginally was possible, and a third group of patients (C; n = 12), in which vaginal delivery was exclusively successful.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The cloning of CD70 and its identification as the ligand for CD27.

CD70 is a surface Ag found on activated but not resting T and B lymphocytes. The biologic activity of this Ab-defined cell surface molecule on lymphocytes has not been established. Therefore, in an effort to understand the function of the CD70 protein, a mAb defining the CD70 Ag was used to isolate by expression cloning the cDNA responsible for the CD70 molecule. The predicted protein product is a type II transmembrane protein. Bioassays demonstrated that the CD70 cDNA clone expressed in African green monkey kidney cells would induce the proliferation of PHA-costimulated T cells. Comparison with known sequences indicates identity with the CD27 ligand. Therefore the molecule defining the CD70 Ag is identical to the recently defined ligand for CD27.

Amino Acid Sequence↗
PubMed1993

Frequency distribution of D1S80 alleles in the German population.

The locus D1S80 is a very useful genetic marker system for forensic DNA analysis. It consists of a variable number of tandem repeats (VNTR) and can be analyzed by the polymerase chain reaction (PCR). As accurate data about the distribution of the alleles is one of the most important prerequisites for the application in forensic biology we studied the allele distribution in the German population.

Base Sequence↗
PubMed1993

[X-ray studies of the peripheral joints: a comparison of digital luminescence radiography (DLR) and film-screen systems].

175 matched skeletal x-ray examinations were carried out by digital luminescent radiography (DLR) and conventional screen-film system combinations. In digital luminescent radiography (DLR) two differently postprocessed images were obtained from one x-ray exposure: A display with low spatial frequency enhancement was opposed to a second display with high edge enhancement. Conventional and digital images were evaluated randomly and separately by four radiologists using a questionnaire. DLR proved to be diagnostically equivalent to the conventional technique except for a diminished visibility of subtle erosions and fissures. As major advantages of DLR maybe pointed out that faulty exposures were avoided by the automatic adjustment of image brightness and that the soft tissue margins could be more easily delineated in displays with high edge enhancement than in conventional radiography. However, digital displays with high edge enhancement did not provide additional diagnostic information and led to artifacts at the edges of metal prostheses.

Adult↗
PubMed1992

Norepinephrine sensitivity of the endocrine pancreas in aging F344 rats.

The effect of norepinephrine (NE) infusion on glucose-stimulated insulin secretion was evaluated in whole perfused pancreases isolated from 6-, 12-, and 26-month-old male Fischer 344 (F344) rats. Glucose-stimulated insulin secretion was significantly inhibited by NE in all age groups. There was no significant effect of aging on the sensitivity or magnitude of inhibition at any of the concentrations of NE. In contrast, vascular pressure attained during NE infusion was significantly less in the 26-month-old rats compared to 6- and 12-month-old animals. These results suggest that the adrenoceptor neuroeffector mechanism of the smooth muscle declines at a faster age-related rate than does the beta-cell's adrenoceptor mechanism.

Aging↗