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Biomedical subjects

M Krause

Publications and source records attributed to M Krause.

At least 199 records · Page 11Linked to original sources
PubMed1992

[Bilateral pheochromocytoma. Is there stimulation of an extra-adrenal adrenaline liberation after bilateral adrenalectomy?].

BACKGROUND: In order to determine plasma and urine epinephrine levels after bilateral adrenalectomy, we examined a 16 year old young man with bilateral pheochromocytoma. Bilateral removal of the adrenals was performed because of a left sided pheochromocytoma relapse. An extra-adrenal pheochromocytoma could be excluded by scintigraphy. Macroscopically all adrenal tissue was removed during surgery. METHODS: A modified radioenzymatic determination of the free catecholamines epinephrine, norepinephrine and dopamine was used according to Peuler and Johnson. Sulfoconjugated catecholamines were measured after addition of 60 microU arylsulfatase type VI. Urine catecholamine levels were determined fluorometrically. RESULTS: The elevated plasma andurine norepinephrine levels before surgery returned to normal after surgery. In contrast, plasma epinephrine levels returned to subnormal values thereafter but increases 5-fold at the end of anesthesia suggesting an extra-adrenal source of epinephrine. Urine epinephrine levels remained in the lower normal range. An insulin induced hypoglycemia was performed resulting in adrenergic symptoms of hypoglycemia and a subnormal increase of epinephrine. CONCLUSIONS: We conclude, that epinephrine mediated physiological regulations occur inspite of bilateral adrenalectomy probably by a regulated extra-adrenal source of epinephrine. The kidney could be the site of extra-adrenal epinephrine production.

Adolescent↗
PubMed1992

[Infectious sinusitis and otitis].

Insight into the pathogenesis and knowledge of the microbial flora provide the basis for the treatment of sinus and ear infections. Reduced oxygen tension and impaired mucociliary transport are important factors that influence the pathogenesis of both acute and chronic sinusitis and otitis. Therefore, topical decongestion and antibiotic regimens belong to the main therapeutic principles. The choice of an antibiotic for treatment of acute infections is usually empiric; however, in chronic and recurrent infections identification of the microbiology by fluid aspiration from the sinus or middle ear is desirable before long-term antibiotic therapy is initiated. It is also important to recognize underlying predisposing conditions such as nasal polyps, anatomic deformities or tooth abscesses which should be corrected to prevent further recurrences. External otitis is a painful condition seen most frequently in the swimming season (swimmer's ear) and is often associated with the use of cotton swabs. Repeated removal of debris from of the external canal and ototopical antibiotics are mostly successful; however, in severe cases like in necrotizing external otitis antibiotic therapy is indicated.

Anti-Bacterial Agents↗
PubMed1991

An active serine is involved in covalent substrate amino acid binding at each reaction center of gramicidin S synthetase.

The condensing peptide forming multienzyme of gramicidin S synthetase (gramicidin S synthetase 2) was specifically labeled at its putative thiotemplate sites for L-valine and L-leucine by covalent incorporation of the 14C-labeled substrate amino acids. The thioester complexes of the multienzyme were digested with CNBr, Staphylococcus aureus V8 protease, and pepsin. Reaction center peptides containing the [14C]valine and [14C]leucine labels were isolated in pure form. They show a high degree of sequence similarity and contain the same consensus sequence LGGH/DXL. The labels were eliminated in the first Edman degradation step. A dehydroalanine was identified which can originate from either a cysteine or a serine. The comparison of the chemical results with the deduced amino acid sequence of the grsB gene encoding the gramicidin S synthetase 2 revealed that 4 such motifs are located within the gene structure, each of them being localized in the 3'-terminal region of one of 4 gene segments grsB1-B4. They have a size of approximately 2 kilobases and presumably code for the 4 amino acid activating domains of the synthetase. Surprisingly a serine was found at each putative substrate amino acid-binding position instead of a cysteine as postulated by the thiotemplate mechanism. Therefore the data suggest that active serine residues are involved in nonribosomal peptide syntheses of microbial peptides.

Amino Acid Isomerases↗
PubMed1991

The myoD gene family: nodal point during specification of the muscle cell lineage.

The myoD gene converts many differentiated cell types into muscle. MyoD is a member of the basic-helix-loop-helix family of proteins; this 68-amino acid domain in MyoD is necessary and sufficient for myogenesis. MyoD binds cooperatively to muscle-specific enhancers and activates transcription. The helix-loop-helix motif is responsible for dimerization, and, depending on its dimerization partner, MyoD activity can be controlled. MyoD senses and integrates many facets of cell state. MyoD is expressed only in skeletal muscle and its precursors; in nonmuscle cells myoD is repressed by specific genes. MyoD activates its own transcription; this may stabilize commitment to myogenesis.

Animals↗
PubMed1991

Syllabic stress and the occurrence of stuttering.

The occurrence of stuttering on stress-peak and unstressed syllables in connected speech was studied in 10 young adult stutterers. Results showed a significant coincidence of stutter events and syllabic stress peaks, particularly in polysyllabic words. Stuttering on the first three words of principal clauses, however, appeared independent of syllabic stress. Similarities between the loci of stutter events and segmental errors of speech are considered in relation to explanations that regard stuttering as evidence of failure in normal speech production processes.

Adolescent↗
PubMed1991

Molecular analysis of the virulence locus of the Salmonella dublin plasmid pSDL2.

The virulence properties of various non-typhoid Salmonella serotypes depend on the presence of large plasmids 60-100 kb in size. We have shown previously that the virulence region on the 80 kb plasmid pSDL2 of Salmonella dublin Lane maps within a 14kb SalI fragment. In this report we show that an 8.2 kb region within this fragment is sufficient to express lethal disease in BALB/c mice. Sequence analysis of this segment revealed six sequential open reading frames designated vsdA-F, which encode putative proteins of 13-65kDa. Deletion analysis and location of Tn5-oriT inserts which abolish virulence suggest that vsdA, vsdC, vsdD and vsdE are essential for virulence expression. Downstream of vsdF we discovered a locus involved in stable plasmid maintenance. Deletion of that region resulted in plasmid multimerization and instability.

Amino Acid Sequence↗
PubMed1991

Genetic analysis of homology between the virulence plasmids of Salmonella dublin and Yersinia pseudotuberculosis.

Two segments within the virulence region of Salmonella dublin plasmid pSDL2 that were homologous to regions on Yersinia pseudotuberculosis plasmid pIB1 were located with regard to the four known genes (vsdA, vsdB, vsdC, and vsdD) of pSDL2. One segment mapped upstream of vsdA within an insertion element related to IS630 of Shigella sonnei; the second was confined to a 45-bp sequence containing an inverted repeat between vsdC and vsdD. On pIB1, both areas were located in an intergenic region upstream of yopH. These results indicate that the homology between Yersinia and Salmonella virulence plasmids is not located within structural genes.

Amino Acid Sequence↗
PubMed1991

Identification of a multimer resolution system involved in stabilization of the Salmonella dublin virulence plasmid pSDL2.

The Salmonella dublin virulence plasmid pSDL2 is a low-copy-number plasmid that is highly conserved in its host. Deletion of the 8-kb EcoRI C fragment downstream of the virulence region leads to plasmid instability and formation of multimers. We identified a multimer resolution system in the EcoRI C fragment composed of a trans-acting resolvase gene and a cis-acting resolution site. The resolvase gene, rsd, maps within a 2-kb EcoRV fragment and appears to be part of a multicistronic unit together with at least two other genes of unknown function. The derived protein, 28.7-kDa in size, is almost identical to the D protein of miniF. The C-terminal region was shown to have substantial similarity to the conserved C-terminal domains of the site-specific recombinases of the integrase family. The cis-acting resolution site, crs, is located upstream of rsd within a 628-bp SmaI-HpaI fragment. It contains eight direct incomplete 17-bp repeats followed by a segment rich in indirect repeats, the latter being homologous to the oriV1 sequence of miniF. crs contains the crossover site for specific recombination and mediates bidirectional promoter activity. A replicative function in analogy to that of oriV1 of F could not be demonstrated. The multimer resolution system was shown to stabilize pACYC184 and is dependent on the recA-mediated formation of multimeric plasmids. Screening different Salmonella serovars with a pSDL2-specific recombination assay revealed that only strains harboring a virulence plasmid encode for resolvase activity. Our results suggest that site-specific recombination contributes to the stable inheritance of pSDL2 and other Salmonella virulence plasmids.

Amino Acid Sequence↗
PubMed1991

Growth regulation of a Salmonella plasmid gene essential for virulence.

The Salmonella dublin plasmid gene vsdC is essential for virulence. We have constructed a vsdC-lacZ translational fusion to demonstrate that vsdC is selectively expressed during the stationary phase of bacterial cell growth. This pattern of expression has been confirmed by mRNA hybridization studies. Carbon starvation is able to induce vsdC expression by limiting bacterial growth. The expression of vsdC is dependent upon an upstream gene, vsdA, whose gene product possesses significant amino-terminus homology with the LysR family of transcriptional activator proteins. We have further demonstrated that vsdC expression is not dependent upon the known Salmonella chromosomal virulence regulatory loci ompR, phoP, and cya-crp and that vsdC can be expressed in a range of nontyphoidal Salmonella serovars, including some serovars in which introduction of the virulence plasmid does not confer mouse virulence. The vsd system provides a model for the study of transcriptional activation, a basis for the development of new expression vectors, and a novel mechanism of virulence gene regulation. Bacterial growth limitation within the phagosomes of host phagocytic cells may be the environmental signal inducing plasmid-mediated virulence gene expression in salmonellae.

Blotting, Northern↗
PubMed1991

Ring Y chromosome: molecular characterization by DNA probes.

A young male with a karyotype of 46,X,+ mar is described. Physical mapping of the marker chromosome by using Y-specific single-copy or moderately repeated DNA sequences as molecular probes showed that, in addition to the heterochromatic part of the Yq, a considerable portion of the euchromatin in both Yp and Yq had been lost. These findings suggest that the marker chromosome is a ring Y, for the generally accepted model of ring formation implies breakages in both chromosome arms. The clinical features of the patient correlated well with the phenotypic changes expected from the loss of genetic material from the Y.

Adolescent↗
PubMed1991

[Assessment of diagnostic lung function and diagnostic laboratory parameters in workers exposed to diesel exhaust below ground in comparison with non-exposed workers].

Toxic gases caused by the use of large Diesel-driven devices in underground mines may lead to impairment of health, especially in the respiratory system. By means of occupational hygiene supervision it may be checked if the effectiveness of accomplished occupational hygiene measures are sufficient. By an enlarged examination programme of the respiratory function and laboratory diagnostic investigation miners exposed to Diesel-exhaust-gas were compared within the above mentioned supervision with a non-exposed population. In this study was not found any difference between the respiratory results attributed to influence of Diesel-exhaust-gas. Among the laboratory parameters the exposition to Diesel-exhaust-gas will only affect the mercapturic acid, however, which also may be influenced by other factors. Under the conditions of the measured low degree of exposition was not found any correlation between the level of mercapturic acids and the duration of exposure as well as to the actual degree of exhaust-gas exposition.

Adult↗
PubMed1991

[Therapy of acute myeloid leukemia in children--results of the AML II/87 multicenter study].

Fifty seven patients entered the cooperative study AML II/87 of the working group "Pediatric Hematology and Oncology" of East Germany. Two patients with initial hyperleukocytosis died prior therapy. 13 patients died within the first 4 weeks of therapy, 3 patients did not respond to therapy, and one patient is not yet in remission. 38 patients (70%) attained a complete remission. 15 patients get a bone marrow transplantation in first CR (10 autologous BMT without purging, 5 allogenous BMT). 12 of them are living and well 3 to 34 months after BMT. 9 of the 23 patients under chemotherapy relapsed, one patient is lost to follow up. 13 patients are living in continuous complete remission. The life table probabilities 48 months after the start of the protocol are 0.43 for disease free survival (DFS) and 0.60 for event free interval (EFI). The respective results of the former protocol AML I/82 were 0.34 for DFS and 0.47 for EFI.

Adolescent↗
PubMed1991

[Early detection of changes in peripheral blood vessels in children and adolescents with insulin-dependent diabetes mellitus using Doppler ultrasound].

A clinically established method for early diagnosis of a macroangiopathy in a preclinical state has not been available so far. It was therefore checked whether vascular changes in diabetics can already be detected in childhood and adolescence by determination of pulse wave velocity using the Doppler ultrasound technique. The pulse wave velocity (PWV) was determined in 63 diabetics with a mean age (mean +/- s) of 16.2 +/- 3.3 years and a mean duration of diabetes (mean +/- s) of 8.5 +/- 4.7 years and in 45 control subjects with a mean age of 15.8 +/- 3.8 years by simultaneous recording of the pulse curves from the femoral artery and the posterior tibial artery. The diabetics had a very much higher PWV than the control group (mean +/- s: 10.9 +/- 1.6 m/s as compared to 9.9 +/- 0.8 m/s; p less than 0.001). In 21 out of 63 diabetics, the values were above the 2s range of controls. Indeed, nine of these 21 patients had values above the 3s range. In the diabetics, there was a significant correlation between PWV and the duration of diabetes and mean blood pressure. Vascular changes can already be demonstrated in childhood and adolescence by measurement of the PWV using the Doppler ultrasound method in diabetics. A longitudinal study would be necessary to establish whether this enables early diagnosis of macroangiopathy.

Adolescent↗
PubMed1990

CeMyoD accumulation defines the body wall muscle cell fate during C. elegans embryogenesis.

We have cloned a gene from the nematode C. elegans that is closely related to the vertebrate MyoD gene family. The nematode gene product, CeMyoD, is a nuclear protein that is expressed specifically in body wall muscle cells. Antibody staining of early embryos shows that CeMyoD accumulates in early blastomeres that will subsequently produce only body wall muscle cells. CeMyoD is not detected in pharyngeal muscle cells or in nonmyogenic lineages. A CeMyoD-beta-galactosidase fusion gene is accurately expressed in myogenic cells that also express CeMyoD. In addition, the beta-galactosidase reporter is expressed as early as the 28 cell stage of embryogenesis in specific blastomeres prior to their clonal commitment to body wall muscle. This early fusion gene activity reveals that part of the specificity for CeMyoD transcription can arise very early in development and that subsequently, negative events may restrict CeMyoD expression in progeny cells not destined to become muscle.

Amino Acid Sequence↗
PubMed1990

Predegenerated peripheral nerve grafts facilitate neurite outgrowth from the hippocampus.

Autologous predegenerated (10 days after transection) (PD) distal stumps of rat sciatic nerves and nonpredegenerated (NPD) nerves were implanted into the hippocampus. Light microscopic examination of sections treated by hematoxylin-eosin and Nauta-Gygax silver method was performed at 2, 4, 8, and 16 weeks following implantation and revealed that two weeks after surgery PD implants were better connected with the surrounding brain tissue than NPD nerve fragments. Greater differences were observed at the 4th week of the experiment. Predegenerated grafts were better vascularized and contained many fibers bridging the site of anastomosis. At the 8th and 16th week, there were, in the microscopic preparations, no visible differences between PD sciatic nerve grafts and NPD ones.

Animals↗
PubMed1990

Homologous DNA sequences on the virulence plasmids of pathogenic Yersinia and Salmonella dublin lane.

Yersinia and Salmonella harbour plasmids that encode traits important for virulence, enabling both pathogenic genera to survive and grow in cells of the reticulo-endothelial organs during systemic infections. We have detected DNA homology between the Salmonella dublin virulence plasmid pSDL2 and the plasmids of the pathogenic Yersinia species pestis, pseudotuberculosis, and enterocolitica. Three regions of pSDL2 were found to share homology with the virulence plasmid pIB1 of Yersinia pseudotuberculosis. Two separate hybridizing segments mapped within the previously characterized 6.4 kb vir region of pSDL2 in the SalI B fragment. The third homologous region involved the replicon of pIB1, which hybridized to the SalI C2 fragment of pSDL2. The virulence plasmid pCD1 from Y. pestis showed similar homology with the three regions of pSDL2. Homologies to the vir and SalI C2 regions of pSDL2 were also found on plasmids from Yersinia enterocolitica serotypes 0:9, 0:3 and 0:5, 27. The discovery of separate homologous regions on the virulence plasmids of Salmonella and Yersinia suggests a distant evolutionary relationship.

Blotting, Southern↗