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Biomedical subjects

B Ehlers

Publications and source records attributed to B Ehlers.

At least 37 records · Page 2Linked to original sources
PubMed1991

Chemoprophylaxis of scrapie in mice.

Three applications of the polyanion pentosanpolysulphate about 2 months before infection of mice with scrapie completely protected animals infected with up to 100 LD50, and considerably prolonged the lifespan of those infected with 100 to 10,000 LD50. The clinical diagnosis was confirmed by immunoblot analysis for the protein of scrapie-associated fibrils.

Animals↗
PubMed1989

[Incidence of intravenous thrombolytic therapy and fatalities in patients with acute transmural myocardial infarct (Q infarct). A study of observations from 1984 to 1987].

All patients admitted to the ICU with acute myocardial infarction (MI) were treated by the same protocol since 1984. We report the results in Q-wave-MI of 1987 compared to 1984. Age (67.2 +/- 12.4 vs. 66.8 +/- 11.4 years), sex distribution (70.1% vs. 71.9% male), time elapse between begin of symptoms and admittance to the hospital (15.5 +/- 27.0 vs. 15.0 +/- 32.5 hours) were similar in both years, but the total number of definite Q-MI decreased by 22% from 135 (1984) to 105 (1987). Inhospital mortality (20% vs. 23%) and ICU mortality (14% vs. 20%) tended to decrease, although differences did not reach statistical significance. This was paralleled by an increase in the rate of i.v. thrombolytic therapy from 17% (1984) to 28% (1987) of all patients with Q-MI. The percentage of patients who definitely received i.v. thrombolysis when all indication criteria were present and all contraindicatory factors excluded increased from 47% (1984) to 97% (1987). We conclude, that the performance of i.v. thrombolysis in all patients, who fulfill the general accepted criteria for thrombolysis may improve clinical course and outcome in a given population of patients with acute Q-wave-infarction.

Aged↗
PubMed1989

[Effectiveness and hemodynamic mechanism of action of blood pressure lowering by intravenous labetalol in patients with a critical increase in blood pressure].

Labetalol (L) was intravenously given to ten patients with an acute elevation of arterial blood pressure above to 200 to 100 mmHg. Blood pressure was controlled in 9 of 10 patients (less than or equal to 170/100 mmHg) with 50 mg in 4, 100 mg in 4 and 200 mg L in 1 patient. In 9 responders, systolic pressure decreased from 207 +/- 20 to 161 +/- 9, diastolic pressure from 107 +/- 11 to 90 +/- 8, and mean pressure from 140 +/- 11 to 113 +/- 5 mmHg, and all pressures remained at these levels during a 25 min control period. Heart rate decreased significantly from 87 +/- 20 to 69 +/- 11 per min and cardiac index from 3.2 +/- 0.8 to 2.6 +/- 0.61/min x m2. Stroke volume index remained unchanged. Total peripheral resistance and pulmonary artery occlusion pressure were not significantly altered but tended to increase, resulting in a small shift to the right of the ventricular function curve. Pulmonary vascular resistance increased significantly from 236 +/- 108 to 314 +/- 132 dyn x sec x cm-5 and mixed venous oxygen saturation decreased from 70 +/- 5 to 65 +/- 8%. Peripheral resistance was considerably higher and cardiac index lower in patients with a heart rate below 70/min. We conclude that L effectively lowers the arterial blood pressure in hypertensive crisis, but the substance should not be used in patients with heart rates below 70/min, as in this case the beta-blocking effect may supervene resulting in a high-resistance low-output state.

Adult↗
PubMed1989

[Predictive value of a combined physiologic-therapeutic oriented score system in patients of intensive internal medicine].

171 consecutive patients of a medical intensive care unit (age 18 to 81 years, mortality 24.6%) who were treated in the ICU for at least 72 hours were investigated in order to test the hypothesis, that the combination of therapeutic scoring (TISS) and physiologic scoring (APS) may improve the prognostic significance of score systems and/or the severity of disease classification in critically ill patients. Discrimination of survivors and non-survivors of the combined score was comparable to the results of isolated scores. A higher weighting of the physiology parameters in the combined score did not improve its prognostic significance. On the other hand, only the combined score implicated a linear increase of mortality with increasing score point values. - We conclude, that the combined score system improves the severity of disease classification in critically ill medical patients.

Adolescent↗
PubMed1987

Repression and reactivation of the variant surface glycoprotein gene in Trypanosoma brucei.

Rapid repression of variant surface glycoprotein (VSG) synthesis is an early event during the in vitro transformation of Trypanosoma brucei from coated bloodstream forms to uncoated procyclic cells. Repression occurs at the transcriptional level and is triggered by the combined action of two signals: a reduction in temperature from 37 to 27 degrees C and the addition of the citric acid cycle intermediates citrate and cis-aconitate. It is shown that synthesis of VSG mRNA can be reactivated up to 8 h after triggering differentiation by releasing either one or both of the signals. After 30 h repression is irreversible. The results suggest that transformation of bloodstream forms to procyclic cells proceeds through a reversible phase to an irreversible committed state. A reversible repression of VSG mRNA synthesis is also observed upon inhibition of protein synthesis in bloodstream forms at 37 degrees C.

Aconitic Acid↗
PubMed1987

RNA turnover in Trypanosoma brucei.

Regulation of variant surface glycoprotein (VSG) mRNA turnover in Trypanosoma brucei was studied in bloodstream forms, in procyclic cells, and during in vitro transformation of bloodstream forms to procyclic cells by approach-to-equilibrium labeling and pulse-chase experiments. Upon initiation of transformation at 27 degrees C in the presence of citrate-cis-aconitate, the half-life of VSG mRNA was reduced from 4.5 h in bloodstream forms to 1.2 h in transforming cells. Concomitantly, an approximately 25-fold decrease in the rate of transcription was observed, resulting in a 100-fold reduction in the steady-state level of de novo-synthesized VSG mRNA. This low level of expression was maintained for at least 7 h, finally decreasing to an undetectable level after 24 h. Transcription of the VSG gene in established procyclic cells was undetectable. For comparison, the turnover of polyadenylated and nonpolyadenylated RNA, beta-tubulin mRNA, and mini-exon-derived RNA (medRNA) was studied. For medRNA, no significant changes in the rate of transcription or stability were observed during differentiation. In contrast, while the rate of transcription of beta-tubulin mRNA in in vitro-cultured bloodstream forms, transforming cells, and established procyclic cells was similar, the half life was four to five times longer in procyclic cells (t1/2, 7 h) than in cultured bloodstream forms (t1/2, 1.4 h) or transforming cells (t1/2, 1.7 h). Inhibition of protein synthesis in bloodstream forms at 37 degrees Celsius caused a dramatic 20-fold decrease in the rate of VSG mRNA synthesis and a 6-fold decrease in half-life to 45 min, while beta-tubulin mRNA was stabilized 2- to 3-fold and mRNA stability remained unaffected. It is postulated that triggering transformation or inhibiting protein synthesis induces changes in the abundance of the same regulatory molecules which effect the shutoff of VSG gene transcription in addition to shortening the half-life of VSG mRNA.

Animals↗
PubMed1985

Analysis of bovine cytomegalovirus genome structure: cloning and mapping of the monomeric polyrepetitive DNA unit, and comparison of European and American strains.

The genome of bovine cytomegalovirus (BCMV) strain 66-P-347 consists of double-stranded, linear DNA with a size of 144 +/- 6 kb. It contains polyrepetitive DNA (prDNA) segments like five other BCMV strains. The restriction patterns of the prDNA of all six strains are very similar and indicate that monomeric prDNA units are either 1950 bp (class I and Ia), 2350 bp (class II) or 2750 bp (class III) in size. The complete unit sequence of strain 66-P-347 (class II) was cloned in bacteriophage vector M13mp7 and mapped by the restriction enzymes EcoRI, BamHI, Bg/I, NaeI, SstII and PstI. From these results the restriction maps of the prDNA of the other five strains were deduced. The 400 bp differences in size between the three prDNA classes are a consequence of the appearance of an internal 200 bp sequence being present one-, three- or fivefold in head-to-tail formation. Hybridization of 35S-labelled recombinant phage DNA to Southern blots with DNA of the different strains leads to the conclusion that prDNA units are present as multimers in tandem formation at both genomic termini in the same orientation. The number of terminal repeat units varies between individual molecules of a strain, but the actual terminal sequences are identical.

Animals↗
PubMed1984

The reticuloendothelial system in scrapie pathogenesis.

A single injection of 1 mg dextran sulphate 500 per mouse considerably prolonged incubation times and produced survivors, even when given 3 days after intravenous or intraperitoneal scrapie infection. Since this compound could be detected in mononuclear phagocytes of spleen and lymph nodes for up to 7 months, it is suggested that it impairs a particular step in the infectious process in these cells of the lymphoreticular system. Blockage of the reticuloendothelial system by trypan blue and silica did not alter the pathogenesis.

Animals↗
PubMed1984

Bovine cytomegaloviruses: identification and differential properties.

Biological properties and restriction enzyme patterns of the slowly replicating herpesviruses isolated from cattle affected with different diseases in North America and Europe were analysed. These virus isolates induced identical plaques that developed within 7 to 9 days in bovine foetal spleen cells and within 5 days in actively growing Georgia bovine kidney cells. These virus isolates were found to be antigenically related when tested in the indirect immunofluorescence test, and antigenic relationships with bovine herpesvirus 1 (BHV-1), BHV-2, BHV-3 or BHV-6 were not detected. The genomes of these strains were shown to have virtually identical cleavage sites when treated with restriction enzymes EcoRI, BamHI, SstII, SphI and HindIII. The resulting restriction enzyme patterns differed strikingly from those of BHV-1, BHV-2, BHV-3 and BHV-6. Because the herpesviruses tested become enveloped on the nuclear as well as on endoplasmic membranes, a process through which they induce cytoplasmic vesicles filled with enveloped viral particles, and because of the unique cytoplasmic inclusions that are induced, we classify them tentatively as bovine cytomegaloviruses.

Animals↗
PubMed1984

Dextran sulphate 500 delays and prevents mouse scrapie by impairment of agent replication in spleen.

Treatment of scrapie-infected mice with dextran sulphate (DS) 500 resulted in considerably reduced spleen titres over a long period of time. Subsequently, the central nervous system disease was delayed or even prevented during the 350-day period of observation. Both effects increased after multiple injections of the compound. The potency of DS 500 to protect against scrapie was greatest when treatment and infection were carried out simultaneously. Under these conditions the lethality of 500 to 1000 LD50 was reduced to almost zero. Treatment as early as 10 weeks before infection still prolonged the incubation periods. Of several other polyions tested, dextran sulphate 5 and pentosan polysulphate also impaired scrapie pathogenesis.

Animals↗
PubMed1983

Towards purification of the scrapie agent.

A method for the partial purification of scrapie infectivity from hamster brain is described. About a 100-1000-fold, 20-fold, and 200-fold enrichment in scrapie infectivity with respect to protein, RNA, and DNA content has been achieved using differential centrifugation, enzyme and detergent treatment. The inbred CLAC strain of hamsters used in our experiments contained about 10 times less infectivity in brain than has been found in randomly bred animals or other inbred strains.

Animals↗
PubMed1978

Paddle cilia and discocilia - genuine structures? Observations on cilia of sensory cells in marine turbellaria.

Kinocilia of epidermal sensory cells in fixed marine Turbellaria often terminate as flattened biconcave discs. The distal part of the ciliary axoneme curves back upon itself forming a 360 degree loop which is enveloped by the plasmalemma. In living animals this structure can be induced by the addition of sodium cacodylate, monobasic sodium phosphate, dibasic sodium phosphate, sucrose, calcium chloride, or formaldehyde to the sea water. Specimens treated with sodium chloride, glutaraldehyde, or osmium tetroxide do not show modified cilia. In animals prepared for EM at low temperature and with a buffered hypotonic fixative less kinocilia are modified than in animals treated with a buffered iso- or hypertonic fixative and at a higher temperature. It is assumed that the unusually shaped cilia, described as "paddle cilia" or "discocilia" in other invertebrates, do not represent a genuine but an artificial structure.

Animals↗