Search PubMed⌕ Search

Biomedical subjects

W Zimmermann

Publications and source records attributed to W Zimmermann.

At least 91 records · Page 5Linked to original sources
PubMed1994

Physical, mental, emotional, and subjective workload components in train drivers.

This study, using 12 train drivers on a high speed track and 11 drivers on a mountain track, tried to differentiate between the physical, emotional, mental, and subjective workload components imposed on the drivers during work. With the simultaneous recording and on-line analysis of heart rate and physical activity, the emotional component in terms of the so-called additional heart rate was separated from the physical component. Mental workload was calculated by the heart rate variability and by shifts in the T-wave amplitude of the ECG. Speed of the train, mode of driving, and stress of the situation were rated by two observers who accompanied the drivers in the cabin. During speeds up to 100 km/h as compared to standstills no heart rate changes occurred, but with speeds from 100 km/h up to 200 km/h heart rate decreased indicating a monotony effect. However, heart rate variability, and T-wave amplitude indicated higher mental load during driving in most speed categories. Starting the train and coming to a halt showed greater emotional workload as compared to moving. Observer ratings of stress and subjective ratings of stress by the drivers revealed several discrepancies. Discrepancies were also seen between workload as indicated by the physiological parameters, and corresponding stress ratings by the observers or by the drivers.

Heart Rate↗
PubMed1994

Sequence conservation in field and experimental isolates of Borna disease virus.

Coding and noncoding sequences were analyzed from field and experimental isolates of Borna disease virus. For a 24-kDa protein, maximum divergence was 1.5% at the predicted amino acid level and 3.1% at the nucleotide level. For a 40-kDa protein, maximum divergence was 1.1% at the predicted amino acid level and 4.1% at the nucleotide level. The highest variability in sequence (10%) was found in a 40-nucleotide stretch of genomic RNA between coding sequences for the 40- and 24-kDa proteins. The degree of sequence conservation in these isolates, passaged in various host species in vivo and in vitro over a period of 64 years, is unusual for negative-strand RNA viruses.

Animals↗
PubMed1994

Borna disease virus: immunoelectron microscopic characterization of cell-free virus and further information about the genome.

The etiological agent of Borna disease, a persistent virus infection of the central nervous system with differently expressed symptomatology, was morphologically unknown. Here we provide the first convincing data on its phenotypic architecture. Salt-released virus comprising the biological parameters of Koch's postulates has an unsegmented single-stranded RNA. A dense band (1.22 g/cm3) in CsCl contains 90-nm particles which appear to be enveloped and a fraction of 50- to 60-nm particles. Labeling of the virions with neutralizing antisera and colloidal gold conjugates indicates that the 90-nm particles most likely represent the causative agent.

Animals↗
PubMed1993

A polymerase-chain-reaction assay for the specific identification of transcripts encoded by individual carcinoembryonic antigen (CEA)-gene-family members.

Carcinoembryonic antigen (CEA) is a tumor marker that belongs to a family of closely related molecules with variable expression patterns. We have developed sets of oligonucleotide primers for the specific amplification of transcripts from individual CEA-family members using the reverse transcriptase/polymerase chain reaction (RT/PCR). Specific primer sets were designed for CEA, non-specific cross-reacting antigen (NCA), biliary glycoprotein (BGP), carcinoembryonic antigen gene-family members 1, 6 and 7 (CGM1, CGM6 and CGM7), and one set for all pregnancy-specific glycoprotein (PSG) transcripts. Primers were first tested for their specificity against individual cDNA clones and product-hybridization with internal, transcript-specific oligonucleotides. Total RNA from 12 brain and 63 gynecological tumors were then tested for expression of CEA-related transcripts. None were found in tumors located in the brain, including various mesenchymal and neuro-epithelial tumors. CEA and NCA transcripts were, however, present in an adenocarcinoma located in the nasal sinuses. In ovarian mucinous adenocarcinomas, we always found co-expression of CEA and NCA transcripts, and occasionally BGP mRNA. CEA-related transcripts were also found in some serous, endometrioid and clear-cell ovarian carcinomas. CEA, NCA and BGP transcripts were present in endometrial carcinomas of the uterus and cervical carcinomas, whereas uterine leiomyomas were completely negative. No transcripts were found from CGM1, CGM6, CGM7 or from PSG genes in any of the tumors tested. The PCR data were compared with immunohistochemical investigations of ovarian tumors at the protein level using CEA (26/3/13)-, NCA-50/90 (9A6FR) and NCA-95 (80H3)-specific monoclonal antibodies.

Antigens, Neoplasm↗
PubMed1993

Genomic organization, splice variants and expression of CGM1, a CD66-related member of the carcinoembryonic antigen gene family.

The tumor marker carcinoembryonic antigen (CEA) belongs to a family of proteins which are composed of one immunoglobulin variable domain and a varying number of immunoglobulin constant-like domains. Most of the membrane-bound members, which are anchored either by a glycosylphosphatidylinositol moiety or a transmembrane domain, have been shown to convey cell adhesion in vitro. Here we describe two splice variants of CGM1, a transmembrane member of the CEA family without immunoglobulin constant-like domains. CGM1a and CGM1c contain cytoplasmic domains of 71 and 31 amino acids, respectively. The cytoplasmic region of CGM1a is encoded by four exons (Cyt1-Cyt4). Differential splicing of the Cyt1 exon (53 bp) leads to the formation of CGM1c. The presence or absence of potential protein kinase phosphorylation sites in the cytoplasmic domains and a sequence consensus motif involved in signal transduction in multichain immune recognition receptors indicates that this splice event is of functional importance. CGM1a mRNA, the predominant CGM1 transcript, was found in the granulocytic lineage, but not in monocytes, lymphocytes nor in a number of tumors derived from all three germ layers. Weak staining using monoclonal antibodies Tu2 and 73 in fluorescence-activated cell scan analyses indicate low concentrations of CGM1 protein on the surface of granulocytes. The CGM1 protein is also recognized by CD66 antibodies. Therefore, the granulocyte-specific CD66 epitope is present on at least four CEA family members: CGM1, CEA, NCA-50/90 and NCA-160.

Amino Acid Sequence↗
PubMed1993

Decolorization of industrial effluents containing reactive dyes by actinomycetes.

Actinomycete strains have been identified which decolorize effluents containing different types of reactive dyes. Adsorption of anthraquinone, phthalocyanine and azo dyes to the cells of some of the strains resulted in the decolorization of the effluents, but no degradation of the dyes was observed. In contrast, effluents containing an azo-copper complex and a formazan-copper complex dye were almost completely decolorized by several of the strains without adsorption to the cells. The observed changes in the visible spectra indicated a degradation during incubation with the strains.

Actinomycetales↗
PubMed1993

Spatiotemporal expression of pregnancy-specific glycoprotein gene rnCGM1 in rat placenta.

As a basis towards a better understanding of the role of the pregnancy-specific glycoprotein (PSG) family in the maintenance of pregnancy, detailed investigations are described on the expression of a recently identified rat PSG gene (rnCGM1) at the mRNA and protein levels. Using specific oligonucleotide primers, rnCGM1 transcripts were identified after reverse transcription, polymerase chain reaction, and hybridization with a radiolabelled, internal oligonucleotide. Transcripts were only found in significant amounts in placenta. In situ hybridization visualized rnCGM1 transcripts at day 14 post coitum (p.c.), in secondary trophoblast giant cells and in the spongiotrophoblast. Only those secondary giant cells lining the maternal decidua were positive. In contrast, primary giant cells did not contain rnCGM1 mRNA. At day 18 p.c., rnCGM1 transcripts were almost exclusively detectable in the spongiotrophoblast. No rnCGM1 transcripts were found in rat embryos of these two developmental stages. Rabbit antisera were generated against the amino-terminal immunoglobulin variable-like domain and against a synthetic peptide containing the last 13 carboxy-terminal amino acids of rnCGM1. Both antisera recognized a 124 kDa protein in day 18 rat placental extracts as identified by Western blot analysis. The anti-peptide antiserum recognized a 116 kDa protein in the serum of a 14 day p.c. pregnant rat that is absent from the sera of non-pregnant females. Taken together, these results confirm exclusive expression of rnCGM1 in the rat trophoblast, but unlike human PSG, negligible or no expression is found in other organs, such as fetal liver or salivary glands, indicating a more specialized function of rnCGM1. Its spatiotemporal expression pattern is conducive with a potential role of PSG in protecting the fetus against the maternal immune system and/or in regulating the invasive growth of trophoblast cells.

Amino Acid Sequence↗
PubMed1993

[Spontaneous growth inhibition in retinoblastoma].

Report on 8 cases with spontaneous arrest of retinoblastoma. The incidence was 3.2% which is approximately 1000 times more than in other malignant tumors. Multifocal lesions suggesting that this form of "regression" may not be a regression at all. Spontaneous arrest of retinoblastoma is obviously a lesion of low malignant potential. The presence of a spontaneous arrest of retinoblastoma necessitates genetic counselling and examinations of the eyes in the offspring. Synonymous names are: 1. Spontane Rückbildung eines Retinoblastoms (spontaneous regression of retinoblastoma), 2. Retinoma, 3. Retinocytoma, 4. benign variant of retinoblastoma, 5. spontaneous arrest of retinoblastoma, 6. spontaneous cure of retinoblastoma.

Adolescent↗
PubMed1993

Transport of tricarballylate by intestinal brush-border membrane vesicles from steers.

Tricarballylic acid is a non-metabolizable rumen bacterial fermentation product of the naturally occurring tricarboxylic acid trans-aconitic acid. The aim of the present study was to investigate intestinal absorption of tricarballylate using brush-border membrane vesicles (BBMVs) isolated from the proximal jejunum of steers by a Ca2+ precipitation method with subsequent differential centrifugation. Transport of tricarballylate was investigated indirectly (influence of tricarballylate on the uptake of 14C-labelled citrate) as well as directly (uptake of 3H-labelled tricarballylate). Citrate as well as tricarballylate uptake (at a concentration of 0.05 mmol l-1) was strongly stimulated by an inwardly directed initial Na+ gradient. Furthermore, transport of both tricarboxylates under Na+ gradient conditions was clearly enhanced by lowering the extravesicular pH from 7.8 to 5.6. The imposition of an inwardly directed H+ gradient (pH(out)/pH(in) = 5.6/7.8) further enhanced the intravesicular accumulation of citrate as well as of tricarballylate compared with pH(out)/pH(in) = 5.6/5.6. Unequivocal evidence for a common transport site for tricarballylate and citrate was obtained from 'cis-inhibition' and 'trans-stimulation' of Na(+)-dependent citrate uptake by tricarballylate. In further experiments the influence of different substances on the uptake of 3H-labelled tricarballylate was evaluated. Unlabelled tricarballylate, citrate, succinate as well as trans- and cis-aconitate significantly inhibited the accumulation of 3H-labelled tricarballylate by BBMVs. Tricarballylate uptake as a function of the tricarballylate concentration revealed a Na(+)-dependent saturable component (apparent kinetic parameters: maximal transport capacity (Vmax) = 119 pmol (mg protein)-1 (3s)-1; affinity constant (Km) = 0.097 mmol l-1) and a Na(+)-independent diffusional component (diffusion constant: 169 nl (mg protein)-1 (3s)-1). It is concluded that tricarballylate and citrate are transported across the intestinal brush-border membrane by a common, Na(+)-dependent transport mechanism. The stimulatory influence of a low extravesicular pH most probably indicates that the protonated forms of tricarboxylates are better transported than the trivalent species.

Animals↗
PubMed1993

Linkage analysis in German breast cancer families with early onset of the disease, using highly polymorphic markers from the chromosome 17q11-q24 region.

Linkage analysis in German breast cancer families with early onset of the disease by using six markers on chromosome 17q11-q24 has been carried out. In the region between markers D17S250 and GH, three markers showed positive LOD scores at an estimated distance of zero. Evidence for linkage is greatest for D17S250, with a LOD score of 2.42.

Adult↗
PubMed1993

[The "hemorrhagic bowel syndrome" of swine: clinical, pathologo-anatomic and etiopathogenic aspects].

In an analysis of autopsy findings from 16,384 pigs (1980-90) 436 cases of haemorrhagic bowel syndrome (HBS) were found (2.66% of autopsies). In most cases fattening pigs (in the weight of 25-100 kg) were affected. HBS was significantly more frequent in females. Intestinal volvulus was confirmed in 56.2% of all cases of HBS, however by more careful examination between 1988 and 1990 even in 80% of cases. In most cases the degree of torsion was 180 degrees and the direction as seen with the pig lying on its back was anticlockwise. Clinical history as reported by owners revealed limited information: sudden death of one or several pigs within three months, association with whey feeding not uncommon. Significantly more cases of HBS were seen during spring and on mondays. Numerous yeasts could be detected in mucosal impression smears of ileum, colon and caecum. Additional analyses in six farms suffering from big losses due to HBS suggested that several environmental and management factors may be involved pathogenetically: feeding only once a day of excessive amounts of a liquid diet, especially whey (a highly fermentable substrate), poor hygiene of liquid diets (high bacterial counts and yeast concentrations). In mixed breeding and fattening units, the aforementioned factors could be responsible also for sudden deaths in dry sows caused by colonic bloat often associated with intestinal rupture and torsions of the stomach and/or the spleen.

Animal Feed↗