Search PubMed⌕ Search

Biomedical subjects

M Friedrich

Publications and source records attributed to M Friedrich.

At least 55 records · Page 3Linked to original sources
PubMed2001

Characterization of 3-[(123)I]iodo-L-alpha-methyl tyrosine transport in astrocytes of neonatal rats.

3-[(123)I]Iodo-L-alpha-methyl tyrosine ((123)I-IMT) is used for diagnosis and monitoring of brain tumours by means of single-photon emission tomography. As recently shown, (123)I-IMT is predominantly mediated into rat C6 glioma cells by sodium-independent system L for large neutral amino acids. Until now, (123)I-IMT transport in non-neoplastic glial cells has not been examined. Therefore, the aim of this study was to examine the cellular pathways and precise transport kinetics of (123)I-IMT uptake into astrocytes of neonatal rats. In particular sodium-independent (123)I-IMT transport into neonatal astrocytes was compared with sodium-independent (123)I-IMT uptake into neoplastic rat C6 glioma cells. Competitive inhibition experiments showed that (123)I-IMT is exclusively transported via sodium-independent system L into the neonatal astrocytes (92%). Kinetic analysis of sodium-independent (123)I-IMT uptake into neonatal astrocytes and into C6 glioma cells revealed apparent Michaelis constants K(M) = 13.9 +/- 0.5 microM and K(M) = 33.9 +/- 4.1 microM, respectively, which are in the same range of K(M) values as those recently determined for amino acid transport into neoplastic and non-neoplastic glial cells. Indeed, the K(M) values in the micromolar range correspond to the expression of the LAT-1 subunit of system L both in the neonatal astrocytes and in C6 glioma cells. However, sodium-independent maximum transport velocities (V(max)) differed significantly between neonatal astrocytes and C6 glioma cells (11.1 +/- 0.3 and 39.9 +/- 3.3 nmol/mg protein/10 min, respectively).

Amino Acid Transport Systems↗
PubMed2001

Complete inhibition of in vivo glioma growth by oncostatin M.

We describe here the oncostatin M (OSM)-dependent inhibition of in vivo tumour formation after intracerebral inoculation of glioblastoma cells in mice. We generated human glioblastoma cells transfected with the OSM gene under the control of a tetracycline-response promoter. Upon removal of tetracycline from the medium, cells exhibited a differentiated cell morphology, while proliferation was significantly inhibited. After implantation of these cells into nude mice brains, large tumours developed in animals lacking OSM expression, whereas no tumour formation was observed in mice with induced OSM expression. Our results suggest that OSM exerts pronounced antitumorigenic effects on glioblastoma cells in vivo and provide arguments for a therapeutic application of OSM in humans.

Animals↗
PubMed2001

Interleukin-10 promoter polymorphism in psoriasis.

Beneficial effects of interleukin-10 therapy and lower endogenous interleukin-10 formation compared with atopic dermatitis and cutaneous T cell lymphomas indicated that interleukin-10 is a key cytokine in psoriasis. The interleukin-10 promoter is highly polymorphic, with two informative microsatellites, interleukin-10.G and interleukin-10.R. In order to understand whether interleukin-10 itself is a predisposing gene for the psoriasis susceptibility we analyzed interleukin-10 promotor polymorphism in patients. The distribution of interleukin-10.G and interleukin10.R microsatellite alleles did not vary between patients (n = 78) and healthy controls (n = 80). In addition, when the psoriasis patients were stratified according to age of onset (younger than 40 y of age, or age 40 and older), no difference in allele distribution was observed; however, a clear differential distribution was revealed at the interleukin10.G locus when patients were stratified according to whether they had a positive family history of psoriasis (p = 0.04). This difference was due to an over-representation of the interleukin10.G13 allele in those patients with familial disease (40.4% vs 19.6%, Chi-square = 7.292, p = 0.007). The positive association of allele interleukin10.G13 with familial psoriasis was especially true when patients with an early onset (< 40 y of age) of the disease were compared with those patients with early onset against a nonfamilial background (39.6% vs 14.5%, Chi-square = 8.959, p = 0.003). Patients with age-of-onset of less than 40 were 4-fold [odds ratio = 3.85 (1.55--9.62)] more likely to have a psoriatic family background if they carried this interleukin10.G13 allele. These data suggest that the interleukin-10 locus contributes to the heritability of psoriasis susceptibility.

Alleles↗
PubMed2001

Determination of erythrocyte antioxidant capacity in haemodialysis patients using electron paramagnetic resonance.

BACKGROUND: The increased oxidative stress of uraemia is caused both by an increased generation of oxygen-free radicals and a decrease of antioxidative forces. There are, however, conflicting data concerning disturbances of the radical-scavenging power of red blood cells (RBCs) in uraemic patients. METHODS: The antioxidant capacities of the RBCs of 10 haemodialysis (HD) patients and 10 controls were examined after treatment with 0.324 mM tert-butylhydroperoxide (t-BOOH) in phosphate-buffered saline at 37 degrees C using electron paramagnetic resonance (EPR) with 5,5-dimethylpyrroline-N-oxide (DMPO) as a spin trap and glutathione (GSH) regeneration as an indicator of hexose monophosphate shunt (HMPS) activity. EPR investigations were also done after pre-incubation with N-ethylmaleimide (NEM) to inhibit the GSH system. Furthermore, we determined the RBC redox state in 15 HD patients and 15 controls. RESULTS: There was no difference between HD patients and controls in the elimination of t-BOOH-generated free radicals in the RBCs. A more than 20-fold increase in radical concentration was observed after GSH trapping with NEM. In this case, we found a delayed decrease of the relative radical concentration in HD patients compared with controls with a significant difference after 7 min (2.2+/-0.26 vs 1.60+/-0.21; P=0.005) and after 10 min (1.82+/-0.41 vs 0.83+/-0.44; P=0.001). GSH regeneration via HMPS did not differ between the RBCs of HD patients (99.5+/-13.5 nmol/min x ml RBC) and those of the controls (94.2+/-16.9 nmol/min x ml RBC). There were no differences in the RBC concentrations of GSH, GSSG, NADP, NADPH, and in the GSH/GSSG and NADP/NADPH ratios between HD patients and controls. CONCLUSIONS: These data suggest a strong antioxidant potential in the GSH system of erythrocytes without any evidence of a disturbance in HD patients. The HMPS pathway also appears not to be impaired in the RBCs of HD patients. However, the slower radical elimination in the RBCs of HD patients after inhibition of GSH-depending radical scavengers as compared with controls indicates a defect in the antioxidant forces outside the GSH system, and could be one reason for the reduced lifespan of RBCs in HD patients.

Adult↗
PubMed2001

Multiple lateral transfers of dissimilatory sulfite reductase genes between major lineages of sulfate-reducing prokaryotes.

A large fragment of the dissimilatory sulfite reductase genes (dsrAB) was PCR amplified and fully sequenced from 30 reference strains representing all recognized lineages of sulfate-reducing bacteria. In addition, the sequence of the dsrAB gene homologs of the sulfite reducer Desulfitobacterium dehalogenans was determined. In contrast to previous reports, comparative analysis of all available DsrAB sequences produced a tree topology partially inconsistent with the corresponding 16S rRNA phylogeny. For example, the DsrAB sequences of several Desulfotomaculum species (low G+C gram-positive division) and two members of the genus Thermodesulfobacterium (a separate bacterial division) were monophyletic with delta-proteobacterial DsrAB sequences. The most parsimonious interpretation of these data is that dsrAB genes from ancestors of as-yet-unrecognized sulfate reducers within the delta-Proteobacteria were laterally transferred across divisions. A number of insertions and deletions in the DsrAB alignment independently support these inferred lateral acquisitions of dsrAB genes. Evidence for a dsrAB lateral gene transfer event also was found within the delta-Proteobacteria, affecting Desulfobacula toluolica. The root of the dsr tree was inferred to be within the Thermodesulfovibrio lineage by paralogous rooting of the alpha and beta subunits. This rooting suggests that the dsrAB genes in Archaeoglobus species also are the result of an ancient lateral transfer from a bacterial donor. Although these findings complicate the use of dsrAB genes to infer phylogenetic relationships among sulfate reducers in molecular diversity studies, they establish a framework to resolve the origins and diversification of this ancient respiratory lifestyle among organisms mediating a key step in the biogeochemical cycling of sulfur.

Amino Acid Sequence↗
PubMed2001

Dissimilatory sulfite reductase (desulfoviridin) of the taurine-degrading, non-sulfate-reducing bacterium Bilophila wadsworthia RZATAU contains a fused DsrB-DsrD subunit.

A dissimilatory sulfite reductase (DSR) was purified from the anaerobic, taurine-degrading bacterium Bilophila wadsworthia RZATAU to apparent homogeneity. The enzyme is involved in energy conservation by reducing sulfite, which is formed during the degradation of taurine as an electron acceptor, to sulfide. According to its UV-visible absorption spectrum with maxima at 392, 410, 583, and 630 nm, the enzyme belongs to the desulfoviridin type of DSRs. The sulfite reductase was isolated as an alpha2beta)gamma(n) (n > or = 2) multimer with a native size of 285 kDa as determined by gel filtration. We have sequenced the genes encoding the alpha and beta subunits (dsrA and dsrB, respectively), which probably constitute one operon. dsrA and dsrB encode polypeptides of 49 (alpha) and 54 kDa (beta) which show significant similarities to the homologous subunits of other DSRs. The dsrB gene product of B. wadsworthia is apparently a fusion protein of dsrB and dsrD. This indicates a possible functional role of DsrD in DSR function because of its presence as a fusion protein as an integral part of the DSR holoenzyme in B. wadsworthia. A phylogenetic analysis using the available Dsr sequences revealed that B. wadsworthia grouped with its closest 16S rDNA relative Desulfovibrio desulfuricans Essex 6.

Amino Acid Sequence↗
PubMed2001

Transient bilateral osteoporosis of the hip in pregnancy. A case report and review of the literature.

Osteoporosis of the hip is a rare complication of pregnancy, the diagnosis of which can only be determined by radiologic means. Differentiation between osteonecrosis and osteoporosis remains problematic in some cases. Magnetic resonance imaging was reported as useful for the diagnosis of osteoporosis. Treatment of osteoporosis of the hip in pregnancy should be conservative including physical therapy, restricted weight bearing and analgetic therapy. We report an unusual case of bilateral transient osteoporosis of the hip in pregnancy.

Adult↗
PubMed2001

The clinical significance of antenatal pathological Doppler findings in the fetal middle cerebral artery in cases with peripheral reduced diastolic doppler flow but no absence of end-diastolic flow in the umbilical artery or fetal aorta.

PURPOSE: The effects of antepartum pathological Doppler findings in the fetal middle cerebral artery in cases with simultaneously peripheral reduced diastolic Doppler flow on perinatal outcome and the odds ratio of perinatal risks were studied. METHODS: 214 patients were examined by color Doppler ultrasound in relationship to complications in gestation and labor and fetal outcome. One thousand and seventy Doppler flow measurements of the middle cerebral artery, the umbilical artery and the fetal aorta between 28 and 40 weeks of gestation were performed. Sensitivity and odds ratio of synchronous cerebral pathological and peripheral pathological Doppler blood flow with regard to the prediction of intrauterine growth retardation, rate of cesarean section, preterm delivery and newborn depression was calculated. In all Doppler measurements there were no cases with absence of end-diastolic flow. RESULTS: Preterm delivery rate and intrauterine growth retardation rate were significantly higher in cases of synchronous cerebral pathological and peripheral pathological Doppler blood flow as in cases of isolated reduced peripheral blood flow (p<0.001; odds ratio 13.2 and 16.6). CONCLUSION: Pregnancies with no absence of end-diastolic flow in the fetal aorta or umbilical artery, but with reduced diastolic flow in these vessels and simultaneous pathological Doppler findings in the fetal middle cerebral artery are high risk pregnancies, above all in respect to intrauterine growth retardation, preterm delivery and newborn depression. Surveillance of pregnant women should be performed in a perinatal centre.

Aorta↗
PubMed2001

The immunolocalization of Bcl-2 in human term placenta.

PURPOSE: To study the immunolocalization of the Bcl-2 protein in formalin-fixed placental tissue collected from uncomplicated term pregnancies. METHODS: A total of 19 human term placentas of 38-41 weeks' gestation, 11 obtained from spontaneous deliveries and eight from elective caesarean sections prior to labour were included. Sections were incubated with an antibody to the Bcl-2 protein and light microscopy was used to evaluate Bcl-2 staining. RESULTS: The anti-apoptotic Bcl-2 protein was expressed diffusely throughout the cytoplasm of the syncytiotrophoblast with much less intensive staining in cytotrophoblast and mesenchymal cells. Bcl-2 expression was reduced or lost in areas of syncytial sprouts. No differences in Bcl-2 staining were observed between placentas obtained after spontaneous deliveries and those collected before the onset of labour after elective caesarean section. CONCLUSION: Expression of the anti-apoptotic Bcl-2 protein in human term placenta does not seem to be influenced by parturition. Additionally, Bcl-2 expression might be an important factor in the regulation of apoptosis in the human trophoblast and thus in maintaining placental function during gestation.

Female↗
PubMed2001

Single atriocaval cannulation is associated with increased incidence of hypercirculatory failure after cardiopulmonary bypass.

UNLABELLED: Cardiopulmonary bypass (CPB) can lead to hypercirculatory cardiac failure (HCF). Despite the activation of inflammatory mediators, the infusion of cardioplegic solution into the systemic circulation may result in decreased systemic vascular resistance and thus may cause HCF. The present prospective study was conducted to investigate in cardiac surgical patients the effects of single atrial versus bi-caval venous drainage and intraoperative hemofiltration on the incidence of HCF. METHODS AND RESULTS: 120 patients undergoing coronary artery bypass surgery (CABG) were randomized in 3 groups: A- single atrial cannulation; B- single atrial cannulation and intraoperative zero fluid balance hemofiltration; C- bi-caval cannulation. Myocardial protection was performed using cold crystalloid cardioplegia (Bretschneider's HTK) administrated into the aortic root and moderate hypothermia (32 degree C). Hemodynamics, fluid balance, vasoactive drugs, body temperature, and hemoglobin/hematocrit ratio were recorded during and up to 12 hours after surgery. We noted a significantly increased incidence of HCF in-group A (32%, n=13) and B (40%, n=16) when compared to group C (10%, n=4, p<0.05), with significantly increased requirements for vasoactive medication in patients developing HCF. CONCLUSION: The present study results demonstrate that single atrial cannulation is associated with a significantly higher incidence of HCF. This is presumably caused by infusion of cardioplegic solution into the systemic circulation.

Aged↗
PubMed2001

[Segmental variants of the inferior vena cava--manifestations with embryological correlation in differentiation from secondary vena cava occlusion].

The vast variability of the overall rare congenital anomalies of the inferior vena cava (IVC) are mostly detected by accident through different imaging modalities. These cannot be classed as pathological findings, and should not be confused with lymphomas and has to differ from secondary collateral venous pathways. Based on 656 CT examinations 10.5% known forms of IVC anomalies were found. According to the embryological development three main groups of IVC variants could be nosologically classified: agenesis of the suprarenal IVC, anomalies of the pars renalis and anomalies of the infrarenal IVC. Additionally three unusual anomaly complexes were found. For the understanding details of the embryology based on a simplified depiction are presented.

Adolescent↗
PubMed2000

Activation of the Jak-Stat- and MAPK-pathways by oncostatin M is not sufficient to cause growth inhibition of human glioma cells.

We have recently described that oncostatin M (OSM), a member of the IL-6 family of cytokines, induces the differentiation of human glioma cells in culture. In order to extend this studies, we analyzed the effect of OSM on other human glioma cell lines including A172, U343-MG and T98G. All of these cell lines express the receptor components of OSM and leukemia inhibitory factor (LIF) gp130, LIFR and the OSM specific OSMRbeta. Therefore, we expected these cell lines to respond to OSM and LIF. Using specific antibodies recognizing proteins of the janus kinase (Jak-)/signal transducers and activator of transcription (Stat-) signaling cascade that has been shown to transduce the signals of the IL-6 cytokines to the nucleus, we could show that Jak1, Jak2 and Tyk2, as well as the Stat proteins Stat1, Stat3 and Stat5b were phosphorylated in all three cell lines by OSM and, at least in part, by LIF. Activation of the Stat proteins was also detected by EMSA which revealed complex formation on the Stat3 DNA-binding element and on a Stat5 binding site. Consistent with our recent findings, OSM treatment also induced the activation of the MAPK erk2 and the tyrosine phosphatase SHP-2 in cells of the A172, T98G and U343-MG cell lines. Although this activation pattern was very close to what we had observed in the GOS3 glioma cells, only T98G showed a growth inhibition in response to OSM while the A172 and the U343-MG cell lines did not respond to OSM treatment in terms of growth inhibition.

Antigens, CD↗
PubMed2000

Effect of soil aggregate size on methanogenesis and archaeal community structure in anoxic rice field soil.

In anoxically incubated slurries of Italian rice field soil, CH(4) production is initiated after a lag phase during which ferric iron and sulfate are reduced. The production of CH(4) was affected by the size of soil aggregates used for the preparation of the soil slurry. Rates of CH(4) production were lowest with small aggregates (<50 and 50-100 µm), were highest with aggregates of 200-2000 µm size and were intermediate with aggregates of 2000-15000 µm size. The different amounts of CH(4) accumulated were positively correlated to the concentrations of acetate, propionate and caproate that transiently accumulated in the slurries prepared from different aggregate sizes and also to the organic carbon content. The addition of organic debris that was collected from large-size aggregates to the aggregate size fractions <200 and <50 µm resulted in an increase of CH(4) production to amounts that were comparable to those measured in unamended aggregates of 200-2000 µm size, indicating that CH(4) production in the different aggregate size fractions was limited by substrate. The distribution of archaeal small-subunit rRNA genes in the different soil aggregate fractions was analyzed by terminal restriction fragment length polymorphism which allowed seven different archaeal ribotypes to be distinguished. Ribotype-182 (consisting of members of the Methanosarcinaceae and rice cluster VI), ribotype-389 (rice cluster I and II) and ribotype-820 (undigested DNA, rice cluster IV and members of the Methanosarcinaceae) accounted for >20, >30 and >10% of the total, respectively. The other ribotypes accounted for <10% of the total. The relative quantity of the individual ribotypes changed only slightly with incubation time and was almost the same among the different soil aggregate fractions. Ribotype-389, for example, slightly decreased with time, whereas ribotype-182 slightly increased. At the end of incubation, the relative quantity of ribotype-182 seemed to be slightly higher in soil fractions with larger than with smaller aggregates, whereas it was the opposite with ribotype-80 (Methanomicrobiaceae) and ribotype-88 (Methanobacteriaceae). Ribotype-280 (Methanosaetaceae and rice cluster V), ribotype-375 (rice cluster III), ribotype-389 and ribotype-820, on the other hand, were not much different among the different soil aggregate size fractions. However, the differences were not significant relative to the errors encountered during the extraction of polymerase chain reaction (PCR)-amplifiable DNA from soil. In conclusion, soil aggregate size and incubation time showed a strong effect on the function but only a small effect on the structure of the methanogenic microbial community.

Journal Article↗
PubMed2000

Spinal posture during stooped walking under vertical space constraints.

STUDY DESIGN: Simultaneous spine kinematic variables in sewage workers were quantified using a two-dimensional video-based gait analysis system. OBJECTIVES: To identify patterns of spinal posture in a population of sewage workers pushing waste matter through tunnels while walking stooped under various height constraints. SUMMARY OF BACKGROUND DATA: Working with stooped postures is one of several occupational risk factors that have been associated with spinal disorders. However, the specific changes in spinal posture during stooped walking under various height constraints have not been documented. METHODS: A video-based gait analysis system was used to measure spinal posture in 22 sewage workers. Angles of the cervical, thoracic, and lumbar spine in the sagittal plane were assessed during walking with five levels of height constraint, from upright walking to stooped walking under a headroom restriction of 105 cm. Correlations among gait parameters, demographic data, and clinical results were determined. Linear regression analysis was performed to examine which variables have the largest impact on the posture resulting from a given vertical height constraint when age and body height are held constant. RESULTS: Mean angular values changed significantly with increasing headroom restrictions, with increases in cervical and thoracic extension as well as lumbar flexion. The cervical and thoracic angles were best correlated with height constraint, followed by lumbar angle and stride length. The inverse relation between cervical and thoracic angle during upright walking increased with increasing vertical space constraints, whereas the relation between the thoracic and lumbar angles decreased. Subjects with decreased abdominal muscle strength adopted a significantly more kyphotic thoracic posture when walking under headroom constraints than subjects with normal abdominal muscle strength. CONCLUSIONS: Combined walking and pushing under vertical space constraints was associated not only with the expected increased flexion of the lumbar spine, but also with greater extension (i.e., reduced kyphosis) of the thoracic spine.

Adult↗
PubMed2000

Divergent decapentaplegic expression patterns in compound eye development and the evolution of insect metamorphosis.

In the fruit fly Drosophila, the patterning genes decapentaplegic and wingless contribute to the spatial control of retina development in an antagonistic manner. We examined the expression patterns of these genes in the developing visual system of the hemimetabolous grasshopper Schistocerca americana and the primitive holometabolous beetle species Tribolium castaneum. The pattern of wingless expression was strongly conserved as a pair of lateral domains at the anterior margins of both the developing retina and the developing optic lobes. The expression of decapentaplegic, on the other hand, is different. Unlike in Drosophila, no decapentaplegic expression was detected before the onset of photoreceptor differentiation in the retinal precursor tissue of either grasshopper or beetle. Moreover, the subsequent expression of decapentaplegic in the latter species was not concentrated in the moving front of retina differentiation, as in Drosophila, but observed in anterior and posterior regions. Our results indicate that Drosophila eye development contains elements of both ancestral and derived regulatory gene functions. The requirement for decapentaplegic as an antagonist of wingless during the early development of the Drosophila retina might have originated during the evolution of insect metamorphosis.

Animals↗
PubMed2000

[Fulminant pulmonary embolism after cesarean section].

On the first day after an uneventful emergence caesarean section a 36-year-old woman developed circulatory collapse requiring cardiopulmonary resuscitation for 15 minutes. After resuscitation the patient remained haemodynamically unstable and was clinically highly suspected to suffer from fulminant pulmonary embolism. In this situation the physicians caring for the patient decided to perform a surgical pulmonary embolectomy without previous diagnostic workup. Massive emboli were removed from both pulmonary arteries. Postoperatively the patient recovered and was transferred to a rehabilitation center without severe cerebral sequelae.

Aged↗
PubMed2000

FTY 720A mediates reduction of lymphocyte counts in human renal allograft recipients by an apoptosis-independent mechanism.

The novel immunosuppressive compound FTY 720A posseses a mode of action which is different from all other immunosuppressive drugs. The most prominent feature is a reversible decrease in peripheral lymphocyte counts observed in animal experiments. We investigated in the first human trial (phase 1) whether FTY 720A induces apoptosis of peripheral blood mononuclear cells (PBMC) in stable renal allograft recipients. Monitoring of lymphocyte counts revealed a significant and dose-dependent decrease within 6 h post-FTY 720A dose: placebo 5.1%; 0.25 mg 36.4%; 0.5 mg 40.8%; 0.75 mg 39.4%; 1 mg 45.8%; 2 mg 67.2%; 3.5 mg 64.9%. PBMC apoptosis rates did not change, as determined before intake of FTY 720A and 2 h, 6 h, 24 h and 96 h post-FTY 720A dose. We detected no significant difference in apoptosis rates between patients who received placebo or FTY 720A. However, in vitro experiments showed that high concentrations of FTY 720 A induced apoptosis in human PBMC.

Apoptosis↗