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Biomedical subjects

S Hoffmann

Publications and source records attributed to S Hoffmann.

At least 127 records · Page 7Linked to original sources
PubMed1993

Acute mercury poisoning (acrodynia) mimicking pheochromocytoma in an adolescent.

A 14-year-old boy was seen because of irritability, insomnia, lethargy, and profuse sweating, together with hypertension (blood pressure: 160/120 mm Hg), tachycardia, and a diffuse erythematous rash with desquamation of the palms and soles. Initial biochemical investigation suggested a diagnosis of pheochromocytoma, but subsequently a history of exposure to mercury vapor was obtained. This case emphasizes the clinical and biochemical similarities between mercury poisoning (acrodynia) and pheochromocytoma.

Acrodynia↗
PubMed1993

[Comparative study of immunologic consequences of autotransfusion and homologous transfusion in lung cancer surgery].

A study was carried out to determine the effects of transfusion with either autologous or homologous blood in 35 patients with lung cancer undergoing lung surgery. The patients were randomly allocated to two groups, "allo" receiving homologous blood (n = 10), and "auto" receiving autologous blood only (n = 13). A third control group included the patients (n = 12) who had not required any blood. In patients of "auto" group, two blood removals of 7 ml.kg-1 each were performed, provided their haemoglobin concentration was over 110 g.l-1 and their haematocrit over 34%. The following parameters were studied at t-1 (the day of inclusion), t0 (just before surgery and transfusion), t1 (one week after surgery), and t2 (one month later): haematocrit and haemoglobin concentration; IgG, IgA and IgM concentrations; polymorphonuclear and neutrophil leucocyte and lymphocyte numbers, lymphocyte subpopulations (CD4/CD8), activated natural killers (NK), polymorphonuclear leukocyte chemotaxis and chemoluminescence. Anaesthesia and surgery initiated initiated an early decrease in immunity in all three groups. The immune profile, and its time course in patients who received autologous blood only was similar to that of those who were not transfused at all. On the other hand, homologous blood transfusion seems to modify the recipient's non specific immune system. In group "allo", a decrease occurred in the number of auxiliary lymphocytes CD4, an increase in suppressor lymphocyte numbers CD8, with an increase in the CD4/CD8 ratio, and no increase in NK activity. These data suggest that autologous transfusion is well tolerated in cancer patients undergoing surgery.

Adult↗
PubMed1993

Clinical and experimental evaluation of intermittent intraoperative short-term expansion.

To assist in the closure of defects in the region of the head lack and neck, a number of surgeons recommend intermittent intraoperative short-term expansion to exploit the biomechanical properties of the skin. It was the aim of this study to assess quantitatively the amount of intraoperative "tissue gain," to analyze its origin, and to throw light on its underlying biomechanical processes. A total of 285 expansions in 5-minute intervals under a constant tissue pressure of 100 mmHg were performed on 30 patients with severe microtia. The volumes achieved were protocolled, and microcirculation was monitored with the help of a laser-Doppler flowmeter. Expanders exerting a tissue pressure of 100 mmHg for more than 80 cycles lasting 20 minutes also were employed in five dogs. Apart from determining the volumes, changes in distance between the skin tattoos and the diameter of the expander base were recorded. A volume increase of about 10 percent per hour was recorded for the human patients and an increase of about 30 percent per hour for the animals. After reaching a maximal increase in length of 15 to 20 percent, there was no further skin elongation despite increasing volumes. Instead, the expander began to move into the subcutaneous tissue so that its diameter showed a continuous increase. We can conclude on the basis of these results that the increase in volume during intermittent intraoperative short-term expansion is not caused by the proclaimed "creep" behavior of the skin.

Animals↗
PubMed1993

Human cytomegalovirus IE86 protein interacts with promoter-bound TATA-binding protein via a specific region distinct from the autorepression domain.

The major immediate-early gene of human cytomegalovirus encodes several isoforms of an immediate-early protein which has distinct transcriptional regulatory properties. The IE86 isoform autorepresses the major immediate-early promoter by directly binding the cis repression signal element located between the TATA box and the mRNA cap site. In addition to this activity, IE86 stimulates other viral and cellular promoters. One mechanism by which eukaryotic regulatory proteins are thought to stimulate transcription is by contacting one or more general transcription factors. We show that the IE86 protein physically interacts with the DNA-binding subunit (TATA-binding protein) human transcription factor IID via the TATA-binding protein-contacting domain in the N terminus of IE86. In a mobility shift assay, IE86 was also observed to stabilize the binding of TATA-binding protein to promoter DNA. The domains within IE86 responsible for mediating transactivation and repression functioned independently. These experiments thus demonstrate the elegant ability of human cytomegalovirus to join different protein domains to produce distinct multifunctional proteins.

Base Sequence↗
PubMed1993

Direct interaction of the human cytomegalovirus IE86 protein with the cis repression signal does not preclude TBP from binding to the TATA box.

The human cytomegalovirus major immediate-early gene encodes several protein isoforms which autoregulate the major immediate-early promoter (MIEP). One of these isoforms, the IE86 protein, represses the MIEP through a DNA sequence located between the TATA box and the transcription initiation site, designated the cis repression signal (crs). Through mutational analysis, amino acid domains within IE86 responsible for binding the crs element were located at the C terminus. Mutation of the putative zinc finger domain, which precluded IE86 from binding DNA, converted the protein from a repressor of MIEP transcription into an activator. DNase I protection analysis demonstrated that the IE86 footprint overlapped the sequence protected by the TATA-binding protein (TBP). Investigation of whether IE86 was able to displace TBP from DNA revealed that both proteins could bind DNA simultaneously. However, higher concentrations of IE86 were required to obtain protection of the crs element in the presence of prebound TBP. Similarly, higher concentrations of TBP were required to obtain protection in the presence of prebound IE86. These observations indicate that steric hinderance impairs but does not prevent both proteins from binding DNA synchronously.

Base Sequence↗
PubMed1993

Analysis of heavy metals content in the brain with the use of electron paramagnetic resonance in a clinically unusual case of hepato-lenticular degeneration.

An analysis of heavy metals content in the brain of a clinically unusual case of hepatolenticular degeneration was performed with the use of paramagnetic resonance. The studies established a manyfold increase of copper content in the brain in the form of free ions, and, less significant, also in the form of copper multi-ion clusters. The content of iron in the studied brain was lower than in controls. These results confirmed significantly the neuropathological diagnosis of hepato-lenticular degeneration.

Adult↗
PubMed1992

Rejection prophylaxis with interleukin-2 receptor antibody BT 563: mechanisms of action on human cells.

We investigated the in vitro immunosuppressive effect of BT 563, a monoclonal antibody, against the alpha-chain of the human interleukin-2 (IL-2) receptor (p 55), which has been used to prevent transplant rejection in several clinical trials. We also measured the proliferative T cell alloresponse and pCTL frequencies of BT563-treated kidney transplant patients. In mixed lymphocyte cultures BT 563 caused a reduction of T cell proliferation to about 50%. This could not be reversed by the addition of exogenous IL-2. A more effective reduction (80%) was seen in the generation of cytotoxic T cells from CML cultures and at the clonal level. The specific T cell response after preincubation with antigen and BT 563 was not reduced so that BT 563 did not induce tolerance. The in vitro findings indicated that BT 563 had a significant but incomplete immunosuppressive effect. This correlated with the clinical course and ex vivo analysis of PBL from BT 563-treated patients after kidney transplantation.

Antibodies, Monoclonal↗
PubMed1992

Aspergillus fumigatus fungaemia and myocarditis in a patient with acquired immunodeficiency syndrome.

Necrotizing myocarditis due to Aspergillus fumigatus was a contributory cause of death in a patient with acquired immunodeficiency syndrome and non-Hodgkin lymphoblastic malignant lymphoma of the Burkitt type. A transient remission of the lymphoma had been obtained by cytostatic treatment. A. fumigatus was isolated from blood two weeks before death, but myocarditis was not diagnosed until autopsy.

Acquired Immunodeficiency Syndrome↗
PubMed1992

An algorithm for a selective use of throat swabs in the diagnosis of group A streptococcal pharyngo-tonsillitis in general practice.

A prospective evaluation was made of an algorithm for a selective use of throat swabs in patients with sore throat in general practice. The algorithm states that a throat swab should be obtained (a) in all children younger than 15 years; (b) in patients aged 15 years or more who have pain on swallowing and at least three of four signs (enlarged or hyperaemic tonsils; exudate; enlarged or tender angular lymph nodes; and a temperature > or = 38 degrees C); and (c) in adults aged 15-44 years with pain on swallowing and one or two of the four signs, but not both cough and coryza. Group A streptococci were found by laboratory culture in 30% of throat swabs from 1783 patients. Using these results as the reference, the algorithm was 95% sensitive and 26% specific, and assigned 80% of the patients to be swabbed. Its positive and negative predictive values in this setting were 36% and 92%, respectively. It is concluded that this algorithm may be useful in general practice.

Acute Disease↗
PubMed1992

[Neutral and zwitterionic detergents: dependence of biological effectiveness on critical micellar concentration].

The biological activity of various zwitterionic and nonionic detergents was studied as a function of the corresponding critical micellar concentration (CMC-values). The criteria chosen to measure biological activities were inhibition of bioluminescence, lysis and cell-killing of Vibrio fischeri, hemolysis, and inhibition of Daphnia magna. When Zwittergent-detergents were studied in three different bioassays their biological activity increased with decreasing CMC-values. However, the biological activity of various TWEEN-detergents and alkylglucopyranosides depended on CMC-values in a very different way. We therefore conclude that CMC-values, length of alkylgroups and charge are parameters not yet sufficient to predict the potential toxicity of detergents.

Animals↗
PubMed1992

Electron paramagnetic resonance analysis of heavy metals in the aging human brain.

Electron paramagnetic studies of heavy metals were performed with the use of a Radiopan spectrometer on autopsy material of 5 aged patients (mean age 80.2 years) and 15 control patients (mean age 29 years). The obtained results lead to the following conclusions: 1. The aging brain is characterized by a tendency to decrease in concentration of isolated Cu2+ ions, and a marked decrease in concentration of Fe3+ ions as well as of free radicals, whereas the concentration of Cu2+ clusters is significantly increased. 2. The cases showing both arteriosclerotic and senile degenerative changes are characterized by higher concentrations of Cu2+ clusters than the brains with dominance of the arteriosclerotic process, whereas the concentrations of isolated Cu2+ and Fe3+ ions as well as that of free radicals do not differ between the two subgroups. 3. The diminished concentrations of Cu2+ and Fe3+ ions and free radicals observed in brains of old persons and concomitant with increased concentration of multi-ion aggregates (clusters), more marked in cases of senile atrophy of Alzheimer type, seem to result from some slow-down of metabolic processes in the aging brain.

Adult↗
PubMed1992

Does physical exercise influence bowel transit time in healthy young men?

An examination was performed on 20 healthy men, who had a specific diet, to test the influence of moderate physical activity on bowel transit. During a 3-day pause and a 3-day phase of easy sports activity (jogging), oro-anal transit was measured with the help of radiopaque markers (Hinton method). While the subject was under exertion, the entire weight of stool rose significantly (743 vs. 600 g), whereas we found no significant influence on the oro-anal transit time (39 vs. 48 h) or on stool frequency (1.3 vs. 1.3 per day). Moderate physical activity had no effect on bowel transit time of healthy men under a constant diet. The effect of the so often recommended increase of physical activity on constipation remains to be elucidated.

Adult↗
PubMed1991

Alpha B crystallin accumulation is a specific response to Ha-ras and v-mos oncogene expression in mouse NIH 3T3 fibroblasts.

The conditional expression of the v-mos and Ha-ras(EJ) oncogenes in NIH 3T3 cells leads to the accumulation of a 23-kDa protein (p23) (R. Klemenz, S. Hoffmann, R. Jaggi, and A.-K. Werenskiold, Oncogene 4:799-803, 1989). We purified p23 to homogeneity and determined part of the amino acid sequence. The obtained sequence is identical with that of the eye lens protein alpha B crystallin. Northern (RNA) blot and Western immunoblot experiments were performed to demonstrate that alpha B crystallin mRNA and protein do indeed accumulate as a consequence of v-mos and Ha-ras oncogene expression. Comparison of cDNA clones obtained from the mRNA of eye lenses and of oncogene-expressing fibroblasts revealed identity between them. The major transcription initiation site of the alpha B crystallin gene in our experimental system was shown by primer extension experiments to be identical with the one used in eye epithelial cells. In addition, we identified a second minor initiation site 49 nucleotides further upstream. Serum growth factors did not stimulate alpha B crystallin expression in growth-arrested cells.

Amino Acid Sequence↗
PubMed1991

Low yield of screening for cryptococcal antigen by latex agglutination assay on serum and cerebrospinal fluid from Danish patients with AIDS or ARC.

From July 1, 1989 to September 5, 1990, 530 serum specimens and 50 cerebrospinal fluid (CSF) specimens from 334 HIV-1 infected patients, most of whom had AIDS or ARC, were analysed in a cryptococcal antigen latex agglutination assay, and all were negative. Three cases of meningitis due to Cryptococcus neoformans diagnosed by microscopy and culture in 3 HIV-1 infected patients are presented. Stored specimens of serum and CSF from these patients were assayed for cryptococcal antigen, and in all 3 the onset of meningitis was preceded by the presence of cryptococcal antigen in serum. It is concluded that the low occurrence of cryptococcosis in our patient population does not justify a routine serum screening for cryptococcal antigen.

AIDS-Related Complex↗