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Biomedical subjects

M Naumann

Publications and source records attributed to M Naumann.

At least 19 recordsLinked to original sources
PubMed1992

Candidate proto-oncogene bcl-3 encodes a subunit-specific inhibitor of transcription factor NF-kappa B.

The NF-kappa B subunits p50 and p65 and the product of the rel proto-oncogene are members of a growing class of transcription factors with a unique DNA-binding and dimerization domain. Nuclear transfer of each of these factors is controlled by cytoplasmic inhibitors, and regulated by specific stimuli. The inhibitors I kappa B-alpha and -beta and pp40 recognize either p65 or the c-rel protein. We show here that the proto-oncogene bcl-3, believed to be involved in certain human B-cell leukaemias, encodes a protein that functions as an I kappa B-like molecule for native NF-kappa B but is specific for the p50 subunit. The ankyrin repeat domain of the bcl-3 product is shown to mediate complex formation with NF-kappa B dimers by contracting the conserved dimerization domain of NF-kappa B.

B-Cell Lymphoma 3 Protein↗
PubMed1992

The ankyrin repeat domains of the NF-kappa B precursor p105 and the protooncogene bcl-3 act as specific inhibitors of NF-kappa B DNA binding.

The inducible pleiotropic transcription factor NF-kappa B is composed of two subunits, p50 and p65. The p50 subunit is encoded on the N-terminal half of a 105-kDa open reading frame and contains a rel-like domain. To date, no function has been described for the C-terminal portion. We show here that the C-terminal half of p105, when expressed as a separate molecule, binds to p50 and can rapidly disrupt protein-DNA complexes of p50 or native NF-kappa B. Deletion analysis of this precursor-derived inhibitor activity indicated a domain containing ankyrin-like repeats as necessary for inhibition. The protooncogene bcl-3, which contains seven ankyrin repeats, can equally inhibit p50 DNA binding. These observations identify bcl-3 as an inhibitor of NF-kappa B and strongly suggest that the ankyrin repeats in these factors are involved in protein-protein interactions with the rel-like domain of p50. Comparison with other ankyrin repeat-containing proteins suggests that a subclass of these proteins acts as regulators of rel-like transcription factors.

Amino Acid Sequence↗
PubMed1992

Sex hormone binding and peritumoural oedema in meningiomas: is there a correlation?

Steroid receptor binding activity was evaluated in specimens of 28 human cerebral meningiomas using a dextran coated charcoal (DCC) assay. Oestrogen receptor (ER) binding activity at significant levels (greater than 10 fmol/mg protein) could be detected only in three postmenopausal females (11% positive cases) at low levels. Positive progesterone receptor (PR) binding was detected in eighteen of the twenty-eight analysed meningioma tissues (64% positive cases). A significantly higher level of PR in male than in female patients could be demonstrated. The degree of peritumoural oedema could be evaluated from CT scans. There was no significant correlation between lack and amount of peritumoural oedema and quantity of cytosolic PR binding activity. Therefore we conclude, that peritumoural oedema is related to other factors and a possible role of PR activity in development of peritumoural oedema and growth control of meningiomas could not be demonstrated.

Adult↗
PubMed1991

Expression in vivo of additional plasmid-mediated proteins during intestinal infection with Yersinia enterocolitica serotype O8.

The decisive aspect of Yersinia enterocolitica virulence in vivo is the ability of the plasmid-bearing bacteria to resist the immune response within the host tissue. The expression of plasmid-mediated virulence proteins was investigated in the intestinal lumen and in the Peyer's patches of infected mice. Three novel plasmid-mediated outer-membrane proteins have been identified with antisera raised against bacteria grown in vivo. When the bacteria were grown in the intestinal lumen, all plasmid-coded proteins known to be expressed in vitro, except the 26-Kda protein were expressed. Additionally, a novel outer-membrane protein of 23 Kda was synthesised. After penetration into the Peyer's patches, two further proteins of 240 and 210 Kda were expressed. None of these three proteins was detected in the outer membrane of bacteria grown in vitro. By contrast, plasmid-coded released proteins, which are abundantly synthesised in Ca(2+)-deficient media in vitro, were not detectable in the ileal lumen nor in the tissue of infected Peyer's patches, which suggests that they are not required for Y. enterocolitica pathogenesis.

Animals↗
PubMed1991

Humoral and cellular defense against intestinal murine infection with Yersinia enterocolitica.

The role of phagocytes and the complement system as potential host defense mechanisms against bacterial infection were studied in mice with two isogenic strains of Yersinia enterocolitica serotype O8 differing in pathogenicity because of differences in plasmid content. Complement depletion in mice by intraperitoneal injection of cobra venom factor did not affect the course of colonization of the intestinal tissue by each strain, indicating that in mice complement is not essential for the elimination of these bacteria. This conclusion is supported by the fact that fresh murine serum had no bactericidal effect in vitro either on the pathogenic or on the nonpathogenic strain. However, in the intestinal tissue as well as in the peritoneal cavity, only the pathogenic, plasmid-bearing Y. enterocolitica strain survived, while the nonpathogenic, plasmidless strain was rapidly eliminated. Since elimination from the peritoneal cavity is due to phagocytosis by polymorphonuclear leukocytes and macrophages, resistance to phagocytosis in vivo seems to be the decisive factor determining the virulence of pathogenic Y. enterocolitica strains.

Animals↗
PubMed1991

[Computer-assisted optimal regulation of combustion engines at work sites].

This is a report about the fundamentals of computerised optimation of duration of operation and air exchange for the use of working machines and cars with internal combustion engines in workrooms. The computer programme 'EMI', which bases on the corresponding national standard TGL 33,358/01 to /03, is suitable for the dialog work with the operator. On the foundation of the ensuring compliance with the maximum working place concentration values MAKK and MAKD it is possible to optimize the contrary requirements like air exchange and duration of operation of the internal combustion engines. The programme can be used for GDR-usual computers. It is possible to order the computer programme 'EMI' including user hints at Mansfeld Industrieanlagen Dresden.

Air Pollutants, Occupational↗
PubMed1991

Sleep patterns in aircrew operating on the polar route between Germany and east Asia.

The study was performed as the second part of an investigation to assess sleep behavior and circadian rhythmicity in aircrew operating regular passenger flights between Germany and East Asia via Anchorage (ANC). Continuous records of sleep and ratings of sleep quality were obtained by sleep logs from 101 B747-cockpit crewmembers, starting at least 3 d before commencing flight duty, continuing during days on duty (the duration depending on the flight schedule) and finishing 4 d after return, at the earliest. Regardless of the specific duty roster, sleep deficit occurred mainly after the first flight leg to ANC, presumably due to the 10-h time zone difference and the short layover time. During the layover in the Far East, the sleep deficit diminished partly because of additional naps. Sleep was often disturbed and scattered over days and nights. Another pronounced sleep deficit occurred after the first return flight from South Korea or Japan to ANC. Compared to the outgoing layover period in ANC, the number and duration of naps increased during this layover and, additionally, on the first 2 d after returning home. Poorer sleep quality ratings were associated with accumulated sleep deficit and increased napping, but significant decrements in sleep quality were seen only during two out of the six different duty rosters. All six of the polar route duty rosters may lead to significant sleep disturbances. During some flight schedules the sleep deficit is large enough to raise operational implications.

Adult↗
PubMed1990

Factors influencing meningioma recurrence rate.

The authors studied retrospectively 23 recurrent meningiomas of a total series of 277 intracranial meningiomas operated upon in the Department of Neurosurgery, University of Würzburg, between 1983 and 1989. All tumours were diagnosed by CT scan or MRI and operated upon using modern neurosurgical operation technology such as CUSA, Neodym-YAG-laser and if necessary operating microscope. Age, sex and tumour site could not be demonstrated as an influencing factor of tumour recurrence. Histological subtype and cellular criteria (mitoses, nuclear pleomorphism, focal necrosis) also were not predictive for tumour recurrence in the individual case. We found longer recurrence-free intervals after complete tumour removal (Simpson's grade I or II) than after subtotal tumour excision (Simpson's grade III or IV), but this tendency was not statistically significant. Obviously the analysed factors especially histomorphological criteria and surgical grading do not reflect the total biological behaviour of recurrent meningiomas. Further studies on growth kinetics and tumours metabolism may help to solve this problems.

Adult↗
PubMed1990

Maffucci's syndrome with bilateral cartilaginous tumors of the cerebellopontine angle.

Maffucci's syndrome is characterized by the combination of multiple enchondromas (Ollier's disease) and hemangiomatosis. These hemangiomas develop in the subcutaneous tissue and form red-blue tumors dispersed over the whole body. Intracranial involvement is rare, making a preoperative radiological diagnosis and differentiation from other tumors rather difficult. The radiological characteristics and successful removal of the intracranial part of a chondrosarcoma of the cerebellopontine angle in a case of Maffucci's syndrome are reported in this paper.

Adult↗
PubMed1990

Purification and characterization of glucose-6-phosphate dehydrogenase from Pseudomonas W6.

Glucose-6-phosphate dehydrogenase (EC 1.1.1.49) has been purified from methanol grown Pseudomonas W6 by a simple procedure involving dye-ligand affinity chromatography on Cibacronblue F3G-A-Sephadex and Procion Red HE-3B-Sepharose. The purification procedure yielded a homogeneous enzyme with (1) high specific activity of 390 and 500 units/mg with NADP and NAD, respectively, and (2) low concentrations of contaminating activities. The molecular mass of the native enzyme was estimated to be 123 +/- 5 kDa. For the polypeptide chain after SDS denaturation a molecular mass of about 61 kDa was calculated. The kinetic behaviour of glucose-6-phosphate dehydrogenase exhibiting activity with either NADP or NAD was studied with respect to the substrate and coenzyme affinities and to ATP inhibition of enzyme activity. The applicability of prepared glucose-6-phosphate dehydrogenase as an auxiliary enzyme in clinical tests is discussed.

Chromatography, Affinity↗
PubMed1989

Affinity chromatography of bovine heart lactate dehydrogenase using dye ligands linked directly or spacer-mediated to bead cellulose.

A number of reactive dyes coupled to bead cellulose directly or spacer-mediated has been investigated in respect of their interaction with lactate dehydrogenase (LDH; E.C. 1.1.1.28) from heart muscle. The Procion dyes Red HE-7B and Navy H-ER, as well as the Remazol dyes Brilliant Blue R and Brilliant Red 5-BN directly bound to bead cellulose provide high binding of LDH and the adsorbed enzyme is eluted specifically from these affinity adsorbents in high yield. In contrast, under the same conditions no binding of LDH has been found to the Procion dyes Green H-4G, Yellow HE-3G, Scarlet MX-G and Orange MX-G, although an opposite behaviour was expected from the results of affinity partitioning in aqueous two-phase systems. However, immobilizing these dyes via a spacer generated strong binding of the enzyme to the affinity adsorbent. The influence of the length of the spacer was studied in respect of the binding capacity and the yield of the enzyme specifically eluted. The applicability of Procion Scarlet MX-G-(diaminohexyl)-bead cellulose for the purification of LDH from muscle extract in one chromatographic step was demonstrated.

Animals↗
PubMed1989

Determinants of invasion and survival of Yersinia enterocolitica in intestinal tissue. An in vivo study.

The invasion of intestinal tissue by Yersinia enterocolitica was studied after infection of mice with plasmid-bearing or with plasmidless strains of serotype 08 and 03. Within the first 15 h of infection each strain colonized the mouse ileum to the same extent, indicating that the initial binding and invasion are not plasmid dependent. This conclusion is supported by the finding that the plasmidless and the plasmid-bearing Yersiniae (serotype 08) colonize the ileum in a quantitatively similar, dose-dependent manner. The data show that the virulence of Yersiniae depends primarily on their ability to survive and to proliferate within the tissue. This character was expressed by the plasmid-bearing 08 strain, but not by the plasmidless 08 and 03 strain nor by the plasmid-bearing 03 strain. An orally induced rabbit antiserum was used to identify plasmid-coded antigens (relative molecular masses = 47, 45 and 42 kDa), which are expressed in vivo by the plasmid-bearing 08 strain, but not by the three other strains investigated. These antigens may be crucial for virulence of the 08 strain.

Animals↗
PubMed1989

Immunohistochemical and electron microscopic study of interaction of Yersinia enterocolitica serotype O8 with intestinal mucosa during experimental enteritis.

The experimental infection of mice with Yersinia enterocolitica serotype O8 was investigated in a quantitative and histological study. The course of bacterial penetration and spreading was precisely determined by immunohistochemical staining. After oral administration, the bacteria passed the epithelial barrier of the ileum and spread into the lamina propria. By preference they entered Peyer's patches, which were about 1,000 times more heavily colonized than the surrounding epithelium of a comparable surface area. The bacteria proliferated in the follicles, from which they spread into the lamina propria of the villi. At either site most of the bacteria multiplied extracellularly, with only a small percentage observed to be present within the phagocytes. The bacteria did not appear to be able to pass the intact basement membrane; hence, the integrity of the basement membrane is likely to play a role in determining the route of entry and limit of spread of Y. enterocolitica infection.

Animals↗
PubMed1989

[Determination and occupational health evaluation of pollutant concentrations from combustion engines in occupational environments].

For ensuring compliance with the maximum working place concentration values MAKD and MAKK for the use of internal combustion engines in workrooms, new directives for the determination of pollutant emissions, the calculation of working place concentrations, and the industrial-hygienic assessment are now available in form of the completely revised version of the national standard TGL 33,358/01 to 03 which is mandatory as from August 1st, 1988. Here, contrary to the former methodology pursuant to TGL 32,610/02, a partly additive, partly individual assessment of the pollutants is made. The inclusion of further emission sources in the industrial-hygienic assessment is envisaged. For the projecting stage, a mathematical estimation model has been developed which considers such requirements as air exchange and duration of use of the internal combustion engines already in the planning stage. Practice-orientated examples are given to facilitate the application of this directive for control bodies of industrial-hygiene, projectors, and other users.

Air Pollutants, Occupational↗
PubMed1986

Interactions of immobilized and free triazine dyes with glucose-6-phosphate dehydrogenase from yeast.

Glucose-6-phosphate dehydrogenase (EC 1.1.1.49) prepared from baker's yeast binds to immobilized Cibacron Blue F3G-A and Procion Red HE-3B. In this paper the two dyes are compared with respect to their use in the purification of this enzyme. Cibacron Blue chromatography was found useful at an early stage of purification for the removal of contaminating hexokinase, phosphoglucose isomerase and phosphoglucomutase. With Procion Red HE-3B Sepharose the NADP dependent enzymes phosphogluconate dehydrogenase and glutathione reductase are separable from glucose-6-phosphate dehydrogenase. Unlike Cibacron Blue gel chromatography, the enzyme can be specifically eluted from Procion Red HE-3B Sepharose by a NADP gradient. Other monochlorotriazine dyes like Xirone Brillant Red BHD, 4BHD, 6BHD and GHD and the dichlorotriazine dye Procion Brown MX-5BR immobilized to Sepharose have only little binding affinity to glucose-6-phosphate dehydrogenase. The binding behaviour of different immobilized triazine dyes for pre-purified and purified glucose-6-phosphate dehydrogenase is compared. In addition, the influence of the free dyes on the activity of glucose-6-phosphate dehydrogenase is studied. It is demonstrated that the results of kinetic and binding studies with the purified enzyme are not uncritically applicable for the selection of a dye as ligand for affinity chromatography during enzyme preparation.

Chromatography, Affinity↗