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Biomedical subjects

D Hofmann

Publications and source records attributed to D Hofmann.

172 records · Page 10Linked to original sources

[Clinical aspects and problems in thoracic dystrophy].

We report about a child with Jeune-syndrome in whom surgical enlargement of the thorax at the age of 4 months was performed. In the beginning there was a significant improvement of the respiratory situation. Due to resorption of the interposed ribs there was again a shrinking of the thorax and a deterioration in the child's condition. A reoperation at the age of 8 months couldn't improve the situation anymore, because at that time the child had already additional problems such as pulmonary hypertension and broncho-pulmonary dysplasia. We overview the literature and line out our opinion about the indication for surgical enlargement of the thorax in children with Jeune syndrome.

Asphyxia Neonatorum↗

[Pappataci fever].

Sandfly fever virus is known to cause pappataci fever. The sandfly fever virus belongs to the Genus Phlebovirus (family: Bunyaviridae) and is endemically found in areas of South Europe, Asia and Africa. In Germany, pappataci fever is only described in connection with travelling to endemic areas. We report on a 15 year-old girl suffering from sandfly fever virus infection after vacation in Turkey. The initial symptoms started with fever for about three days, frontal headache, nausea and arthralgia. After a short time of clinical improvement symptoms recurred and our patient entered hospital with signs of severe meningitis. Liquor analysis showed a lymphocytic meningitis. Due to multiple insect bites on her legs sandfly fever was suspected. Blood analysis confirmed an acute infection with sandfly virus Sicilian from which she completely recovered. ELISA and immunoblot analysis revealed an infection with sandfly virus serotype Sicilian, which was not encountered with meningitis so far. Our case report illustrates that due to increased tourism sandfly fever virus infection has to be considered as a cause of aseptic meningitis in travellers.

Adolescent↗

MR imaging in pediatric airway obstruction.

Magnetic resonance (MR) imaging of the trachea was performed in 27 children with congenital tracheal narrowing. The diagnoses included aortic arch anomalies (n = 7), innominate artery compression (n = 13), pulmonary artery compression (n = 5), and tracheomalacia (n = 2). Demonstration of the trachea and the surrounding tissue and vessels on MR images allowed the evaluation of the cause of tracheal compression and the degree and location of collapse. Patients were examined with MR imaging if the cause of airway obstruction was still unclear after bronchoscopy. It is concluded that MR imaging is a well suited modality for characterizing tracheal narrowing without using ionizing radiation or intravenous contrast medium.

Airway Obstruction↗

Expression and purification of recombinant HIV-1 tat protein using HIV-1-tat specific monoclonal antibodies.

We expressed tat protein from HIV-1 coding AA 1-67 (strain HIV-Bru) in the inducible vector pTrc 99A in E. coli. The tat coding region was cloned in the ATG site of the expression vector. A sequence coding for 15 AA was added at the 3'region as a molecular marker. After sonification, the tat protein was routinely detected in Western blots using the Mab developed by us. Following precipitation and centrifugation the resulting pellets were dissolved and purified by three different methods: 1. immunoaffinity-chromatography using Affi-gel HZ coupled with a Mab recognizing the N-terminal sequence of HIV-1-tat; 2. ion exchange chromatography using DEAE-52 cellulose, and 3. isoelectric focusing in free solution. The resulting protein extracts obtained from the three purification protocols were checked in ELISA with the antibody. The peak fraction from all the procedures showed tat activity. No cross reaction in the presence of sera from uninfected persons was observed. The results showed that the purification of tat protein using monoclonal antibodies leads to highly purified preparations.

Antibodies, Monoclonal↗

Inhibition of tat-mediated HIV-1-LTR transactivation and virus replication by sulfhydryl compounds with chelating properties.

D-Penicillamine, a structural analog of cysteine, has the ability to chelate metal ions and reacts with cysteine. We have shown earlier that D-Penicillamin is a potential inhibitor of tat-mediated transactivation of HIV-1-LTR (14) and possesses anti-HIV-1 activity (23). Following this approach, we evaluated the anti-tat and anti-HIV-1 activity of several sulfhydryl compounds with chelating properties. The tested compounds: N-(2-Mercapto-propionyl)-glycin (MPG), 2,3-Dimercapto-propanol (DMP) and 2,3-Dimercapto-propane-sulfonic acid (DMPS) exhibited an inhibitory effect on the tat-mediated transactivation in Jurkat cells, as well as in U937 cells. The highest inhibitory response was shown by DMP leading to about 50% inhibition of transactivation in Jurkat cels and an 80% inhibition in U937 cells. On the contrary, DMPS (30 micrograms/ml) had no inhibitory effect in U937 cells, but did exhibit a 50% inhibition of transactivation in Jurkat cells at 30 micrograms/ml. The antiviral activity of DMP and DMPS was evaluated in H9 cells. In the concentration range which is effective for antiviral effect, both the compounds were highly cytotoxic. Mercapto-propionyl-glycin, although a weak inhibitor of transactivation, was able to inhibit synctia formation to more than 90% and inhibit the viral antigene expression to about 70%. The concentration of MPG needed to achieve this antiviral effect was very high, but it had no cytotoxicity at this concentration. We suggest that a search for compounds using this approach may be useful in developing potential inhibitors of tat-mediated transactivation.

Anti-HIV Agents↗

The significance of bronchial and nasal provocation tests in making the diagnosis of allergy in children.

The relationship between positive skin tests and positive provocation tests at the affected organ level was studied in children with rhinitis and bronchial asthma. Of 357 positive skin reactions against pollens only 49% were positive in rhinometry, while of non pollen allergens only 31% of 59 challenges were positive. Of 778 challenges with pollens 40% gave a positive bronchial response, while only 27% of 848 challenges with non pollens were positive. More detailed information is given on single allergens and the consequences for hyposensitation therapy are discussed.

Airway Resistance↗

Expression of a reverse transcriptase activity in a cell line established from peritoneal macrophages of mice treated with N-methyl-N-nitrosourea.

We have established a cell line from peritoneal macrophages of mice treated intraperitoneally with N-methyl-N-nitrosourea. The present communication describes the identification of an RNA-dependent DNA-polymerase activity in a particulate fraction from supernatants of the cell culture. This activity is similar to retroviral Reverse Transcriptase (RT) based on its template specificity and ionic preference. The proof of the retrovirus-like nature of RT was obtained by ultracentrifugation of the pelleted proteins secreted in the medium on a sucrose gradient. The main RT activity was obtained in fractions of 1.14-1.16 g/ml densities, which are comparable to those of type C retroviruses. The presented data support constitutive expression of the retrovirus gene in a chemically transformed cell line.

Animals↗

The establishment of a macrophage-like cell line (Ymnu) from NMRI mice treated with N-methyl-N-nitrosourea. II. Induction of differentiation of Ymnu cells: a cytochemical and immunocytochemical study.

The Ymnu cell line established by us from peritoneal exudate cells of mice treated with methylnitrosourea is of macrophage origin. We have shown that 54% of these cells possess Fc-gamma receptors and can bind opsonized erythrocytes; 30% of these cells express the nonspecific esterase and 65% the Mac-1 antigen, indicating these cells are dedifferentiated. Treatment of the cells with various differentiation inducers led to time-dependent redifferentiation of the cells. The expression of the nonspecific esterase increased to 51.1% (TPA), 42.5% (RA), 63.6% (DMSO), 40.6% (SB). The fraction of Mac-1 positive cells increased to 90.5% (TPA), 80.6% (RA), 84.5% (SB) and decreased to 52.7% (DMSO). The maximal effects of the chemicals on expression of these two parameters were achieved at different times following treatment. While RA and SB were effective after one day, the maximum effect of TPA was seen at day 5.

Animals↗

The establishment of a macrophage-like cell line (Ymnu) from NMRI mice treated with N-methyl-N-nitrosourea. I. Characterization of the cell line.

Here we describe the establishment of a cell line from peritoneal exudate cells for NMRI-mice treated with methylnitroso urea, which we designate Ymnu. Tests for macrophage specific characteristics have shown that 54% of Ymnu cells possess Fc-gamma receptors, 30% are nonspecific esterase positive and 65% possess the macrophage specific antigen Mac-1, indicating their macrophage origin. Although of macrophage origin, the majority of these cells are round, 13 microns in diameter. The cells grow partially in suspension and have doubling times varying from 3 to 1.75 days depending on serum concentration. Cultures of Ymnu cells achieve after 14 days densities 4 times higher than those achieved by NIH-3T3 cells. Ymnu cells have lost the anchorage dependence of growth and grew very well on semi-solid media. In addition, they possess an oncogenic potential and build tumors when injected subcutaneously in nude mice.

Animals↗

Characterization of the RNA dependent DNA polymerase of bovine leukemia virus.

The reverse transcriptase-RNA dependent DNA polymerase of Bovine Leukemia Virus (BLV) was isolated and characterized. The enzyme has a molecular weight of about 80kd and the isoelectric point is 7.6. The enzyme prefers magnesium, as a divalent cation using synthetic homopolymeric template primer poly (C) oligo (dG). Monoclonal antibodies directed against reverse transcriptase of human immunodeficiency virus type I (HIV-I) did not crossreact with the isolated polymerase.

Antibodies, Monoclonal↗