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Biomedical subjects

M Fuchs

Publications and source records attributed to M Fuchs.

At least 163 records · Page 9Linked to original sources
PubMed1993

[DNA flow cytometry of malignant melanoma of the choroid].

Thirty-five choroidal melanomas were analyzed by flow cytometry. DNA euploidy, aneuploidy and polyploidy were found in approximately 54, approximately 46, and approximately 20% of the tumors, respectively. No correlation between histological type and ploidy was found. The synthesis phase was irregular in approximately 25 and approximately 38% of the spindle and the mixed cell melanomas, respectively. The G2M peak was broadened in approximately 50% and in approximately 23% of the spindle and the mixed cell melanomas. About 20% of the malignant melanomas were highly proliferative. In 25% of the melanomas chemotherapy seemed to be useful.

Brachytherapy↗
PubMed1993

[Corrective interventions for malunited fractures of the distal end of the forearm. Indications, choice of procedure, results].

Malunion, non-union, as well as painful ligamentous joint instability following fractures to the distal forearm may seriously compromise the function of a hand. Forty-seven surgically treated cases, thirty-nine of which were followed up, are presented in order to point out the problems of such lesions. Retrospective evaluation of the lesion is absolutely mandatory, as it often dates back to childhood. Management should take clinical findings as well as the patient's functional demands on his hands into consideration, but without overestimating therapeutic potentials.

Adolescent↗
PubMed1993

Post-capillary Immobilon-P membrane fraction collection for capillary electrophoresis.

A simple, cost-effective and efficient method of continuous fraction collection for capillary electrophoresis is described. The method employs a membrane, such as polyvinylidene difluoride, onto which the separated components from a capillary electrophoresis capillary are directly collected to overcome the problem of analyte dilution and to facilitate the fraction collection process. Model proteins are separated and collected onto a polyvinylidene difluoride membrane.

Animals↗
PubMed1993

Bile acid synthesis from newly synthesized vs. preformed cholesterol precursor pools in the rat.

The present study defines the origin of cholesterol subserving bile acid synthesis in male rats with an extracorporal bile duct by labeling newly formed cholesterol with tritiated water. Within 6 hr after interruption of the enterohepatic circulation, the bile acid pool was depleted. At this early time point the proportion from de novo cholesterol was 8% and 12% for biliary cholesterol and cholate, but 18% and 19% for muricholate and chenodeoxycholate, respectively. This proportion gradually rose to 40%, 34%, 51% and 51%, respectively, at 15 to 30 hr. At 78 hr after bile diversion, 64% of cholate was labeled, compared with 84% to 88% of the other biliary lipids and 71% of plasma cholesterol. Total and labeled bile acid secretion exhibited the same diurnal rhythm. To allow differentiation between direct hepatocytic de novo synthesis of bile acids from acetate and recycling of labeled plasma cholesterol, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (pravastatin) was infused from 54 to 78 hr. It suppressed total synthesis of primary bile acids by 60% to 80% but decreased the tritium label of bile acids only from a range of 74% to 92% (54 hr) to a range of 54% to 63% (78 hr), which was in the range of plasma cholesterol (58%). We conclude that bile acids and biliary cholesterol are synthesized mostly from preformed (i.e., plasma) cholesterol, both immediately after depletion of the pool in enterohepatic circulation and after derepression. Moreover, the hepatic cholesterol pools subserving the synthesis of different bile acids and biliary cholesterol secretion are not identical.

Acetates↗
PubMed1992

Effect of the signal-to-noise ratio on the quality of linear estimation reconstructions of distributed current sources.

Currently, linear estimation reconstruction is the only feasible method for extracting information about spatially distributed current sources from measurements of neural magnetic fields. We present the results of a systematic study of the effect of the signal-to-noise ratio on the imaging quality of one such algorithm in over-as well as undetermined circumstances. In particular, we will discuss the necessary trade-off between the contradictory goals of a minimum norm of the reconstructed current density distribution and of a minimal deviation of the reconstructed fields from the measured fields. As an example, we show the reconstruction of a simple arrangement of two nearly parallel dipoles in two different depths inside a spherical volume conductor, discussing the differences between the computer simulation without noise and simulation with a realistic noise level.

Algorithms↗
PubMed1992

[Results of a volar approach to plate osteosynthesis of radius shaft fractures. Theoretical basis--clinical results].

This retrospective study analyses the results of 80 shaft fractures of the radius treated by open reduction and plating by a volar approach. Studies about strain distribution on the radius shaft worked out a varying pattern of tensile forces and a continuously change of the tension bend side through full range of motion. So from the biomechanical aspect an ideal position for compression plating is not determined and dorsal or volar plating brings the same stability. The advantage of the volar approach by Henry is the possibility of an easy extension of the approach to the distal or proximal part of the forearm and an optimal covering of the plate by soft tissue. To expose the superficial radial nerve is obligate, if necessary the deep radial nerve should be exposed too in proximal fractures. From 1973 to 1987 80 fractures of the shaft of the radius were treated by plating using the volar approach, since 1977 3.5 dynamic compression plate of the AO was used exclusively. Only two non-unions occurred in the beginning when the AO's third tube plate was used routinely. One massive callus formation had to be noticed with a complete loss of pronation and supination. One infection occurred, but normal wound healing and bone union could be achieved after early reoperation. Two incomplete lesions of the superficial radial nerve were seen, but normal sensibility occurred spontaneously. No other neural or vascular complication had to be noticed using this approach. In the follow-up 56 patients were seen two to 14 years postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Replication of grapevine fanleaf virus satellite RNA transcripts in Chenopodium quinoa protoplasts.

A set of full-length cDNA clones of the satellite RNA of grapevine fanleaf nepovirus isolate F13 (GFLV-F13) was constructed with a variable number of additional, non-viral nucleotides at the 5' and 3' ends. The biological activity of the RNAs transcribed from these constructs was tested in Chenopodium quinoa protoplasts using a helper virus. When inoculated with arabis mosaic virus S (ArMV-S) RNA as helper, transcripts with 33 non-viral nucleotides at the 5' end (tr45p4) did not replicate, whereas transcripts with only one non-viral nucleotide at the 5' end (tr3S and tr3M) did replicate. Capping of the transcripts enhanced their replication. On the other hand, the presence of extra nucleotides at the 3' end had little influence on the biological activity of the in vitro transcripts. In contrast with ArMV-S, GFLV isolate 24 was not a helper for tr3M transcripts, indicating a specific interaction between the helper strain and the satellite RNA.

Base Sequence↗
PubMed1992

Immunodetection of grapevine fanleaf virus satellite RNA-encoded protein in infected Chenopodium quinoa.

An antiserum was raised against a fusion protein containing the C-terminal half of the protein (P3) encoded by the satellite RNA of grapevine fanleaf virus (GFLV; F13 isolate) and the N-terminal portion of the CI repressor of phage lambda. This antiserum specifically recognized P3 synthesized in the in vitro wheatgerm translation system and also in infected Chenopodium quinoa plants. In these plants, the amount of virus increased for 10 days, then remained constant for up to 21 days, whereas P3 was detected transiently, reaching its maximum on day 10.

Antibodies, Viral↗
PubMed1992

Enterohepatic circulation in hamsters with an extracorporeal bile duct.

The present study describes a novel technique for investigations of the enterohepatic circulation in the hamster with an extracorporeal bile duct that allows long-term bile collection in the free-moving animal. The animals recovered for 7 days after the operation before the external loop was cut and bile was collected over a period of 78 h. Under these optimal conditions, initial bile flow (651 +/- 89 microliters per 100 g.h-1) and the secretion rates of biliary lipids were several-fold higher than reported in an earlier study using the acute fistula hamster. Biliary cholesterol secretion amounted to 369 +/- 32 nmol per 100 g.h-1, phospholipid secretion was 2.6 +/- 0.3 mumol per 100 g.h-1, and total bile acid secretion was 31.9 +/- 2.2 mumol per 100 g.h-1. A clearcut diurnal rhythm was demonstrated for bile flow and all biliary constituents. After 9 h the depletion of the bile acid pool was complete and cholic acid synthesis derepressed 1.4-fold from a basal rate of 818 nmol per 100 g.h-1, whereas the derepression of chenodeoxycholic acid synthesis was even less pronounced. Biliary cholesterol output increased 2.2-fold, but the phospholipid secretion was constant during the full experiment. It may be concluded that the technique of an extracorporeal bile duct in the free-moving animal allows studies of bile secretion under optimal conditions. Most likely the bile secretion rates given above approach the physiological rates in the hamster.

Animals↗
PubMed1992

[Dental status of 12-year-old children].

During the course of a stomatological screening 96% of all twelve-year old children in the district Greiz were examined with respect to the rate of dental caries and malocclusion and oral hygiene index. The results were compared with the targets of the WHO "Health for all by the year 2000".

Child↗
PubMed1991

GroE facilitates refolding of citrate synthase by suppressing aggregation.

The molecular chaperone GroE facilitates correct protein folding in vivo and in vitro. The mode of action of GroE was investigated by using refolding of citrate synthase as a model system. In vitro denaturation of this dimeric protein is almost irreversible, since the refolding polypeptide chains aggregate rapidly, as shown directly by a strong, concentration-dependent increase in light scattering. The yields of reactivated citrate synthase were strongly increased upon addition of GroE and MgATP. GroE inhibits aggregation reactions that compete with correct protein folding, as indicated by specific suppression of light scattering. GroEL rapidly forms a complex with unfolded or partially folded citrate synthase molecules. In this complex the refolding protein is protected from aggregation. Addition of GroES and ATP hydrolysis is required to release the polypeptide chain bound to GroEL and to allow further folding to its final, active state.

Animals↗
PubMed1991

[Relationship between T-subsets and clinical aspects of HIV-associated diseases].

HIV predominantly infects the CD4+ T cells, which during the progression of the disease are eliminated, causing an immune deficiency which renders the patients more susceptible to infections. To evaluate the relevance of the CD4+ T cell elimination and thus the clinical usefulness of CD4/CD8 subset determinations in HIV infected persons, we investigated whether analyses of 667 subset determinations of 365 patients correlated with clinical stages of HIV-infection (CDC classification). Progress of HIV related disease was accompanied by a fall in CD4+ cells and an increase in CD8+ cells, leading to a drastically reduced CD4/CD8 ratio. This change of T-cell subset values correlated well with the clinical classification (CDC). It was, however, only statistically significant if percent values were used, but not if absolute CD4 cell counts, calculated from the peripheral lymphocyte count, were considered. While patients in CDC stage IVC2 (mainly Candida stomatitis) did not differ from stages IIB, IIIB, IVA, we found statistically lower CD4 values if the patients had stage IVA plus IVC2. Stage IVC1 (mainly Pneumocystis carinii pneumonia [PcP, n = 20]) had even lower CD4 values, as PcP appeared almost exclusively in patients with CD4 counts below 20% or 200/microliter. The lowest CD4 counts were observed in patients with Kaposi sarcoma (n = 11) with CD4 cells less than 10% and significant elevated values of CD8 cells (greater than 50%). While the total lymphocyte count correlated with the absolute counts of CD4 and CD8 cells, it was impossible to estimate the T-subset distribution from the absolute lymphocyte count. Our investigations show that a decreased number of circulating CD4 cells correlates well with an increased tendency to develop infections, and thus support the relevance of CD4 cell measurements for the optimal care of asymptomatic HIV infected persons in particular. They also show that the percent values correlate better with clinical stage than the absolute CD4 cell count.

CD4-Positive T-Lymphocytes↗