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Biomedical subjects

A Hoffmann

Publications and source records attributed to A Hoffmann.

At least 343 records · Page 19Linked to original sources
PubMed1990

[Effect of a new gestagen--dienogest--and its combination with ethinyl estradiol on the activity of biotransformation reactions].

Caffeine is mainly metabolized by 3-methyl-cholanthrene-inducible cytochrome P-450, whereas metamizol (Analgin) is probably mainly metabolized by phenobarbital inducible cytochromes P-450. Therefore the elimination of caffeine from serum and the amount of the main metabolites of metamizol excreted into urine reflect the activity of these two cytochrome P-450 families. Sex hormones can influence the activity of cytochrome P-450. Dienogest is a new gestagen, used for temporary contraception. We investigated the effect of this new sexual hormone alone and in combination with ethynylestradiol on the elimination of both testdrugs. In 10 healthy volunteers dienogest 2 mg daily for 14 days have no effect on the metabolism of model drugs whereas the combination with 0.05 mg ethynylestradiol has an influence on the elimination of caffeine and metamizol.

Adult↗
PubMed1990

[Bundle wire nailing in pathological upper arm fractures].

Between 1973 and 1987 we applied stacked Bundle-nailing in 24 cases of pathological humerus fractures. It is a fast, low-risk technique with which a good stabilization can be obtained. Especially in patients with advanced malignant disease, a fast improvement of life-quality is significant.

Aged↗
PubMed1989

[Diagnosis and therapy of malignant peritoneal mesothelioma].

Malignant peritoneal mesothelioma is an uncommon tumor with great diagnostic and therapeutic problems. Symptoms, clinical features and course of the disease are described in three patients which were seen at our hospital within the last years. At the beginning there are often severe weight loss, malaise and sometimes fever of unknown origin. Abdominal pain, increased abdominal girth or nausea indicate advanced tumor stages in most cases. Ultrasonography and computed tomography of the abdomen can give important information during the diagnostic approach. Nevertheless, the definite diagnosis can only be established by laparoscopy or open surgery with biopsy for a histological examination. Despite intern and extern radiotherapy as well as systemic and/or local chemotherapy the prognosis of malignant peritoneal mesothelioma remains unfavourable. Mean survival time ranges from six to 18 months.

Aged↗
PubMed1989

The carboxyltransferase activity of the sodium-ion-translocating methylmalonyl-CoA decarboxylase of Veillonella alcalescens.

Methylmalonyl-CoA decarboxylase of Veillonella alcalescens catalyzed the isotopic exchange between methylmalonyl-CoA and [1-14C]propionyl-CoA or between malonyl-CoA and [1-14C]acetyl-CoA. The exchange was independent of sodium ions and was abolished by avidin. The enzyme also catalyzed the carboxyl transfer reaction from methylmalonyl-CoA to acetyl-CoA yielding propionyl-CoA and malonyl-CoA, and vice versa. The beta subunit was dissociated from methylmalonyl-CoA decarboxylase by prolonged washing of the enzyme while bound via its biotin prosthetic group to monomeric avidin-Sepharose. The beta-chain-depleted enzyme was inactive as a methylmalonyl-CoA decarboxylase but retained carboxyltransferase activity. The beta subunits were specifically protected by Na+ ions from tryptic hydrolysis. Based on these and other observations the following functions may be assigned to the different polypeptide chains of methylmalonyl-CoA decarboxylase: carboxyltransferase (alpha), carboxybiotin-carrier-protein decarboxylase (beta), biotin carrier protein (gamma). The function of the delta chain is unknown.

Biological Transport↗
PubMed1989

Sudden cardiac death after aortic valve surgery: incidence and concomitant factors.

A retrospective analysis of 599 consecutive patients after aortic valve surgery aged 7-82 years (mean 56) was performed. During a follow-up of 1-14 years (mean 4.7 years) a 4-week perioperative mortality of 6.9% and a late annual mortality of 3.6% were observed. Sudden cardiac death was the most frequent single cause of death, accounting for 24% of all deaths. Patients dying suddenly were younger than patients dying from other causes (51 +/- 17 vs. 59 +/- 14 years, p less than 0.05) and showed more left ventricular hypertrophy by electrocardiographic criteria when compared with matched survivors (mean Estes score 5.2 +/- 2.4 vs. 2.8 +/- 1.9; p less than 0.01) and with patients dying nonsuddenly (mean Estes score 5.2 +/- 2.4 vs. 1.8 +/- 1.8; p less than 0.01). Ventricular premature beats in the resting electrocardiogram were more prevalent in patients dying suddenly than in matched survivors (55 vs. 20%; p less than 0.025) as well as in patients dying from other causes (55 vs. 25%; p less than 0.05). In addition, there were more intracardiac conduction disturbances and more ungrafted coronary vessels with insignificant stenoses at the time of surgery in sudden death patients. Our findings suggest that after aortic valve replacement patients with left ventricular hypertrophy, bundle-branch block, and ventricular premature beats in the resting electrocardiogram are at increased risk for sudden cardiac death. A possible etiological role of concomitant coronary artery disease must be considered.

Adolescent↗
PubMed1989

[Loading of polystyrene solid phases with microbial agents and their polysaccharide antigens for the screening of monoclonal antibodies].

Before screening monoclonal antibodies using enzyme immuno assays, it is necessary to prove that the coating of the solid phases occurs efficiently. The adhesion of whole cells of group B streptococci, Escherichia coli K1, Haemophilus influenzae type b and Candida albicans as well as B-Streptococcus group antigen, H. influenzae type b capsular antigen, and C. albicans cell wall antigen to polystyrene solid phases was studied and detected by the following methods: Peroxidase competition procedure, scintillation measurement of 32phosphate-labelled germs, and reactions with monoclonal antibodies.

Antibodies, Monoclonal↗
PubMed1989

Human autoantibody to topoisomerase II.

The rheumatic diseases are characterized by the production of autoantibodies that are usually directed against components of the cell nucleus. In this communication, we describe autoantibodies that recognize DNA topoisomerase II (anti-topoII) present in the serum of a patient with systemic lupus erythematosus. Several lines of evidence indicate that this antibody recognizes topoisomerase II. First, it binds to the native enzyme in soluble extracts prepared from isolated chromosomes and effectively depletes such extracts of active enzyme. Second, the serum binds to topoisomerase II in immunoblots of mitotic chromosomes and chromosome scaffolds. Finally, the antiserum binds strongly to a fusion protein encoded by a cloned cDNA and expressed in Escherichia coli that (based on immunological evidence) represents the carboxy-terminal portion of chicken topoisomerase II. Autoantibodies such as the one described here may provide useful reagents for the study of human topoisomerase II.

Adult↗
PubMed1989

[Transthoracic color Doppler echocardiography in the diagnosis of insufficiency of heart valve prostheses. A comparison with conventional Doppler sonography].

Color-coded and conventional pulsed wave/continuous wave Doppler detection of valvular or paravalvular regurgitation in 59 patients with 67 cardiac valve prostheses were compared; 21 patients had known regurgitation determined by auscultation. Analysis of the color-coded Doppler findings was made from videotape and blinded as to patient identity and clinical findings. Conventional Doppler Sonography detected 36 instances of aortic and 3 of mitral prosthetic regurgitation. Color-coded Doppler investigation detected 27 instances of aortic and 1 of mitral prosthetic regurgitation resulting in a sensitivity of 72% and specificity of 100% as compared to conventional Doppler sonography. All 21 patients with a regurgitant murmur had pathological conventional Doppler findings, but 3 of them did not show regurgitant flow in the color-coded Doppler examination. The apical four chamber view contributed most to the colour-coded Doppler detection of regurgitant flow, followed by the parasternal long axis view.

Adult↗
PubMed1989

Introduction of functional artificial introns into the naturally intronless ura4 gene of Schizosaccharomyces pombe.

Insertion of a 36-base-pair (bp) synthetic oligonucleotide comprising the sequence 5'-GTAGGT(19N)CTAAT (4N)AG-3' into several different positions within the coding region of the naturally intronless ura4 gene of Schizosaccharomyces pombe leads to an efficiently spliced gene producing a functional product. This suggests that the proper signals within an intron are sufficient to initiate and complete a splicing event independent of the location of the intron in the gene. Point mutations in the 5' junction (5'-GTAGGT-3') and in the putative branch sequence (5'-CTAAT-3') affect splicing efficiency significantly. A G-to-A transition at the first nucleotide at the 5' splice junction (5'-ATAGGT-3') abolishes the use of the authentic splice junction and leads to the increased use of an alternative splice site. No functional product is produced from this transcript. An A-to-G transition of the second A in the putative branch sequence (5'-CTAGT-3') lowers the splicing efficiency drastically, but still results in a functional gene product. Furthermore, extension of the 36-bp intron to introns more than 180 bp in size abolishes splicing, suggesting that the splicing apparatus might be restricted to very short introns. We discuss the possibility that S. pombe introns represent a simple type of eucaryotic intron.

Base Sequence↗
PubMed1989

[Mechanisms of thrombin-induced plasminogen activator release].

The protein kinase C inhibitor H7 (10(-5) mol/l) is able to inhibit the thrombin-induced t-PA release in the isolated perfused pig ear. The thrombin-induced t-PA release can be blocked by increasing the intracellular c-AMP via either the activation of adenylate cyclase by means of forskolin, or the inhibition of the phosphodiesterase by means of motapizone or milrinone. Protein kinase C is assumed to be involved in the process of thrombin-induced t-PA release.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

Cytochrome P-450-dependent biotransformation in Uje:WIST rats with chronic liver injury induced by thioacetamide.

In female Uje:WIST rats micronodular liver cirrhosis was produced by thioacetamide (TAA) given in the drinking water (0.3 g/l) from the 4th to 6th months of life. 14 d after TAA cessation it was examined, whether this animal model reflects the restricted cytochrome P-450-dependent biotransformation in severe stages of human liver cirrhosis by in vivo (caffeine and metamizol elimination) and in vitro methods (cytochrome P-450, 7-ethoxycoumarin and 7-ethoxyresorufin O-deethylation, ethylmorphine N-demethylation). The total biotransformation capacity was unchanged in TAA rats, partly even enhanced. Only several in vitro parameters reflect diminished cytochrome P-450-dependent biotransformation calculated per weight unit comparable to severe stages of human liver cirrhosis. Therefore, the chosen experimental conditions are suitable for conclusions concerning cytochrome P-450-dependent biotransformation in early rather than in severe stages of human liver cirrhosis.

Aminopyrine↗
PubMed1989

[Resorption and biotransformation of model substances in primary idiopathic hemochromatosis (siderophilia)].

In 12 patients with primary idiopathic haemochromatosis absorption and biotransformation were measured by model substances. Aim of the investigation was the correlation of the biotransformation of the liver with the degree of liver injury and the clinical picture. We determined in patients and compared with control group: elimination of metamizol in urine, absorption and elimination of caffeine in serum, serum concentrations and elimination of sulfamethazin in urine, absorption of xylose, - In patients with haemochromatosis accompanied with slight liver damage only demethylation of metamizol was slackened. In patients with higher degree of liver damage the elimination of metamizol as well as of caffeine was decreased. Because of the high percentage of slow acetylators in the patient group metabolism of sulfamethazine is decreased. - There was no correlation between iron loading of the organism, absorption of xylose and biotransformation of the model substances.

Adult↗
PubMed1989

Studies on the in-vitro biotransformation in patients with liver diseases.

The activity of 7-ethoxycoumarin O-deethylase (ECOD) was determined in the human liver bioptate of 53 patients with chronic liver diseases. Remarkable are the lower values of ECOD in the hepatoses, chronic hepatitis and cirrhosis as compared to patients with normal histology or residual hepatitis. The decline in the activity of ECOD in the patients with chronic hepatitis and cirrhosis has to be seen in connection with parenchymatous necrosis, nodular liver transformation and intracinar fibrosis. For the time being it is not possible to give a satisfactory explanation of the decrease in the ECOD activity of the hepatoses.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1989

Functional characteristics (EEG) of the thalamo-telencephalic projections of toads.

Electrical or chemical (carbachol) stimulation of the dorsal thalamus of anesthetized and conscious toads induced synchronization (increased number of spindles and increased amplitude of the waves) in the electric tracing (EEG) of the telencephalon. This alteration was accompanied by mydriasis and greater behavioral alert in conscious animals. No recruitment response was observed in anesthetized toads. The present findings were compared to those obtained by stimulating the nonspecific thalamus of mammals and reptiles. Even though the data available at present do not demonstrate the existence of a system with the morphological characteristics of the reticulo-thalamo-cortical system of mammals in anurans, the functional data presented here suggest this possibility.

Animals↗
PubMed1989

[Bundle nailing as an alternative treatment indication in pathologic fractures of the humerus].

In patients with multiple bone metastases of malignant tumors, bundle-nailing according to Hackethal is a fast and non-traumatic way of stabilizing existing or impending pathological fractures. It is also a therapeutic alternative in benign lesions, provided it is genuinely indicated and is performed correctly. Either as primary treatment following resection (sometimes with spongioplasty) or as secondary treatment, i.e. stabilization, it can be a valuable technique. Between 1976 and 1986 we performed 14 operations in our hospital using this technique. The tumor was malignant in 11 cases, benign in 3 and unclear in 1 case. The incidence of unfavorable results due to corrosion has been reduced recently, in particular since titanium has been used.

Adult↗