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Biomedical subjects

E Hofer

Publications and source records attributed to E Hofer.

At least 73 records · Page 4Linked to original sources
PubMed1987

Complementary DNA for human glioblastoma-derived T cell suppressor factor, a novel member of the transforming growth factor-beta gene family.

Human glioblastoma cells secrete a peptide, termed glioblastoma-derived T cell suppressor factor (G-TsF), which has suppressive effects on interleukin-2-dependent T cell growth. As shown here, complementary DNA for G-TsF reveals that G-TsF shares 71% amino acid homology with transforming growth factor-beta (TGF-beta). In analogy to TGF-beta it is apparently synthesized as the carboxy-terminal end of a precursor polypeptide which undergoes proteolytic cleavage to yield the 112 amino-acid-long mature form of G-TsF. Comparison of the amino-terminal sequence of G-TsF with that of porcine TGF-beta 2 and bovine cartilage-inducing factor B shows complete homology, which indicates that we have cloned the human analogue of these factors. It is tempting to consider a role for G-TsF in tumor growth where it may enhance tumor cell proliferation in an autocrine way and/or reduce immunosurveillance of tumor development.

Amino Acid Sequence↗
PubMed1987

T cell suppressor factor from human glioblastoma cells is a 12.5-kd protein closely related to transforming growth factor-beta.

T cell suppressor factor produced by human glioblastoma cells inhibits T cell proliferation in vitro and more specifically interferes with interleukin-2 (IL-2)-dependent T cell growth. Here we report the purification of this factor from conditioned medium of the human glioblastoma cell line 308. Amino-terminal sequence analysis of the 12.5-kd protein demonstrates that eight out of the first 20 amino acids are identical to human transforming growth factor-beta. Purified glioblastoma-derived T cell suppressor factor and transforming growth factor-beta from porcine platelets inhibit both IL-2-induced proliferation of ovalbumin-specific T helper cells and lectin-induced thymocyte proliferation with similar specific activities. If released by glioblastoma cells in vivo, the factor may contribute to impaired immunosurveillance and to the cellular immunodeficiency state detected in the patients.

Amino Acid Sequence↗
PubMed1987

Complementary DNA for human T-cell cyclophilin.

Complementary DNA encoding human cyclophilin, a specific cyclosporin A-binding protein, has been isolated from the leukemic T-cell line Jurkat and sequenced. Comparison of the deduced amino acid sequence with the previously determined sequence of bovine thymus cyclophilin reveals only three differences: an additional amino acid at the carboxy terminus end and two internal changes. RNA transfer blot analysis indicates an mRNA size of approximately 1 kb for human T-cell cyclophilin. Phytohaemagglutinin and phorbol myristate acetate induction of T cells treated or not with cyclosporin A affects only marginally the level of cyclophilin mRNA. Southern blot analysis of human genomic DNA digested with different restriction enzymes strongly suggests the existence of a multigene family for cyclophilin.

Amino Acid Sequence↗
PubMed1987

Analysis of single channel currents with a microprocessor based device.

Data evaluation of single channel currents obtained from artificial black lipid membranes and with the patch clamp method is an important part of every single channel study, but it is a time consuming part often exceeding the time for experimentation and recording by far. We describe here a microprocessor based device, which allows the experimentator to analyse in a simple way the distribution of current levels in a single channel trace (amplitude-histogram analysis of single channel currents) either online, or offline. Current levels are sampled at a constant frequency of 6 kHz and the relative frequencies of occurrence of these current levels are displayed as a histogram on the screen of an analog or digital storage oscilloscope. The data reducing algorithm of this analyser eliminates the requirement of large amounts of mass storage that normally is needed for digital amplitude-histogram analysis of single channel recordings. Examples of evaluation for both a voltage operated cation-channel and a blockage of a potassium channel by tetraethylammoniumchloride (TEA) are given.

Animals↗
PubMed1985

Catheter jet ventilation, a favorable technique during resection of the central tracheobronchial system.

Experience with catheter jet ventilation as an optimal ventilation technique during the critical phase of resection in the region of the central tracheobronchial system (bifurcational resections, extended resections in the bifurcational region) in 9 patients is described. For this technique we use a simple and cheap system consisting of a pressure-reduction valve, an interruption valve manually worked with a pistol handle, 2 manometers and a thin plastic catheter as a jet. In 8 cases the anesthesiologic management during the jet ventilation phase, ranging between 35 and 150 minutes, was without any problem; the one complication and the possible way of solving similar accidents are discussed. In comparison with the conventional technique, catheter jet ventilation gives the surgeon the possibility of complete freedom of action during suturing of the airway anastomosis.

Bronchi↗
PubMed1984

A minimal intron length but no specific internal sequence is required for splicing the large rabbit beta-globin intron.

We constructed rabbit beta-globin genes with deletions in the large intron, extending from the midpoint toward the 5' or 3' splice sites. Analysis of transcripts in transformed HeLa cells showed that six 5' proximal intron nucleotides allowed normal splicing. Correct splicing at the 3' splice site required 12 or more 3' proximal intron nucleotides; optimal efficiency required 24 nucleotides. Remarkably, a mini-intron comprising six 5' and 24 3' intron nucleotides gave no correctly spliced transcripts; extending the miniintron with polyoma or pBR322 fragments to 80 or more nucleotides restored normal splicing. Thus other than in yeast nuclear genes, no specific internal intron sequences appear to be needed but a minimal intron length is important.

Animals↗
PubMed1984

An evaluation of the efficiency of enrichment media in the isolation process for Vibrio parahaemolyticus.

An evaluation of the efficiency of seven enrichment media for Vibrio parahaemolyticus was effected, by means of material collected from the corporeal surface of 82 marine fish caught off the Brazilian coast. On the whole, 45 fish proved positive, from which 71 strains were taken. Among the culture media analyzed the best results were obtained with the new enrichment media represented by two of the nutrient broth (Difco) pH 8.3; one supplemented with 2 g % of NaCl and 500 mg % eosin Y, and another supplemented with 125 mg % metachrome yellow II RD. The combination of enrichment media plus selective-indicator media demonstrated the superiority of the binary association of alcaline broth eosin Y to TCBS agar, both in the number of isolations and serotypes detected.

Animals↗
PubMed1983

Investigations on the mechanism of photodynamic action of different psoralens with DNA.

Investigations on the photodynamic action of psoralens with DNA were performed, using experimental techniques of fluorescence lifetime and NMR-CIDNP, as well as SCF-MO and CNDO molecular orbital calculations. It has been shown that the formation of a biradical through the triplet state is the decisive step for psoralen dimer formation, as well as for cyclobutane addition with thymine, while singlet oxygen production is responsible for enzyme inactivation (e.g., lysozyme and trypsin). The molecular orbital calculations, in agreement with experimental results, indicate that the differences in biological effectivity of different psoralens are based on variations in triplet formation probability.

Animals↗
PubMed1983

Bacteriologic and epidemiologic studies on the occurrence of Listeria monocytogenes in healthy cattles.

The incidence of Listeria monocytogenes in 61 fresh stool specimens from normal beef cattle obtained from a slaughterhouse in Rio de Janeiro was studied. The animals were divided in two groups of similar number separated by age; animals of up to five years, and animals of 5 years and more. In the research of this microorganism 9 culture media were used: four enrichment media, one for transport and four selective media. From the results, 11 animals proved to be carriers, of which nine were five years of age or older and two were of the younger group. Two hundred and twenty-one samples of Listeria were obtained from these 11 animals. The combination of Tryptose broth containing 40 mcg/ml nalidixic acid and 10 mcg/ml trypaflavine, incubated for 5 days at ambient temperature (+/- 28 degrees C), with the second modification of Ralovich medium, showed the best results for detection of Listeria both quantitatively and qualitatively. Among the serotypes characterized in this research the types with greater incidence were L 4 a (60.18%), L 4 f (20.36%), and L 4 b (9.05%).

Abattoirs↗
PubMed1982

Globin RNA transcription: a possible termination site and demonstration of transcriptional control correlated with altered chromatin structure.

The transcription unit that encodes beta-globin (major) mRNA has been examined by analysis of nascent labeled RNA from the nuclei of mouse erythroleukemia cells treated with agents that induce beta-globin formation. More than 95% of the time, transcription appears to terminate within a region 1400 +/- 100 nucleotides downstream from the poly(A) site. The nuclei of mouse erythroleukemia cells treated with agents that induce beta-globin synthesis showed a 10 to 20 fold stimulation of transcription assayed by chain elongation of beta-globin RNA sequences, including sequences downstream from the poly(A) site. Associated with the increase in transcription was a generalized increase in sensitivity to DNAase treatment of globin genomic DNA in whole nuclei. A DNAase I-hypersensitive site in the vicinity of the cap site was also found to be prominent in induced cells.

Animals↗
PubMed1980

[Deep venous thrombosis: streptokinase treatment with adaptation of the maintenance dosage].

Prolonged infusion of streptokinase at the customary dose of 100 000 u/h results in undesired plasminogen depletion in many patients. This can be avoided by adaptation of the streptokinase maintenance dose to the presumed rate of plasminogen synthesis of each individual patient. The practicability of this approach was tested in 52 patients who had streptokinase therapy of 3 to 9 days duration for deep vein thrombosis. Twice daily measurements of thrombin time and fibrinogen concentration were performed for immediate clinical surveyance and dosage adjustments. These led to a change from the original 100 000 u/h in most patients: in 65% the dose was reduced and in 10% it was increased. By this measure excessive plasminogen depletion was avoided in 88% of the patients. In them the final maintenance dose ranged from 40 000 to 150 000 u/h. Side effects were similar to those reported for the standard dosage scheme, and clinical results were good with a phlebographic success rate of 91% in recent and 65% in subacute or chronic deep vein thrombosis.

Adult↗