Search PubMed⌕ Search

Biomedical subjects

M Becker

Publications and source records attributed to M Becker.

At least 343 records · Page 19Linked to original sources

Persistence of benzo[alpha]pyrenediolepoxide DNA adduct in mouse skin.

The covalently bound products of [3H]benzo[alpha]pyrene (BP) were determined in the DNA isolated from the skin of mice 3 weeks after application of the carcinogen. In the relatively rapidly proliferating skin the persistence of BP-DNA adducts was observed, 50% of which were unmodified nucleosides. Small amounts of (7R) BPDE I-dG adduct (5% from the initial formation) were found after 3 weeks. The minor adducts observed at 18 h after treatment were excised.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

The measurement of lymphocyte size and thymidine uptake in comparative response to mitogen stimulation in vitro.

Measurements of thymidine uptake and cell size with the Coulter ZBI Counter and C-1000 channelyzer were found to be comparable for mitogen-stimulated lymphocytes. These two technics show a discrete relation with correlated regions of high and low response. Electronic sizing was correlated linearly to microscopic sizing of lymphoblasts. The reproducibility of radiolabeled and electronic sizing measurements were similar and significantly better than that of manual microscopic sizing. The distribution of lymphocyte sizes after two or three days in culture with mitogen was found to be bimodal. This facilitated the direct detection of stimulation responses with the ZBI counter.

Cells, Cultured↗

Inhibition by prostaglandin E2, somatostatin and secretin of histamine-sensitive adenylate cyclase in human gastric mucosa.

The effects of prostaglandin E2 (PGE2), somatostatin and secretin on gastric mucosal adenylate cyclase (AC) and their interactions with the histamine-sensitive AC were studied using biopsy specimens of normal human gastric mucosa. PGE2 (10(-7) to 10(-3) mol/l), somatostatin (10(-9) to 10(-5) mol/l), secretin (10(-9) to 10(-6) mol/l) and histamine (10(-7) to 10(-3) mol/l), all stimulated mucosal AC in a concentration-dependent manner. Besides this effect, PGE2, somatostatin and secretin significantly inhibited the histamine-activated enzyme at concentrations as low as 10(-10) to 10(-7) (PGE2), 10(-9) to 10(-6) (somatostatin) and 10(-9) to 10(-5) mol/l (secretin). They were more potent than cimetidine which initiated inhibition at concentrations exceeding 10(-7) mol/l. The data show that PGE2, somatostatin and secretin have a dual action on AC: (1) they all activate human gastric AC on their own, and (2) they all inhibit the histamine-sensitive enzyme at the parietal cell level at nanomolar concentrations, thus underlining the concept that hormonal control is essential in the regulation of gastric acid secretion.

Adenylyl Cyclase Inhibitors↗

An index of risk for obstructive airways disease.

Predictors of obstructive airways disease (OAD) have been identified, and models for estimating risk of developing OAD have been derived for the adult population of Tecumseh. Men and women 16 to 64 yr of age when first studied were reexamined after an average interval of 15 yr. Incidence rates of OAD increased with age and were higher in men than in women more than 45 yr of age. Incidence rates were significantly higher in men and women with low degrees of lung function initially, and in cigarette smokers, especially those who continued to smoke. Other risk factors included a physician's diagnosis of chronic bronchitis, or asthma, a history of cough, wheeze, shortness of breath, frequent upper or lower respiratory tract infections, bronchitis or pneumonia, leanness, and familial chronic bronchitis. Multiple logistic regression analyses identified combinations of risk factors that placed 70% of the male and 73% of the female incidence cases in the top 10% of the risk distribution. The excess risk of obstructive airways disease associated with cigarette smoking and reduced lung function and the benefits of stopping smoking are clearly apparent. For example, the risk of developing obstructive airways disease in the next 15 years is about 1 in 200 for a 45-yr-old male nonsmoker whose Vmax50 equals to 100% of predicted, if he doesn't take up smoking. The risk for a man of the same age who smokes 40 cigarettes a day and whose Vmax50 equals 80% of predicted is 1 in 5 or 6 if he doesn't cut down on his smoking and about 1 in 15 if he stops smoking.

Adolescent↗

[Haemodynamic and cardiac and respiratory changes during enflurane-monoanaesthesia in the Göttingen minipig (author's transl)].

Two groups of 10 Göttingen minipigs each were anaesthetized with enflurane in a mixture of O2 and N2O for 90 minutes. One group breathed spontaneously. In the other controlled respiration was used following relaxation with succinylcholine-chloride. Control values of ECG, blood pressure, aortic blood flow, arterial oxygen and carbon dioxide tensions, arterial pH, the maximum rate of rise of the left ventricular pressure (max. dp/dt) were recorded from all animals. Anaesthesia was induced with enflurane using a face mask. On reaching the stage of deep surgical anaesthesia the pigs were quickly intubated and anaesthesia was maintained for up to 90 minutes. Max. dp/dt, blood gas tensions and pH were measured again 60 minutes after induction of anaesthesia. A third arterial blood sample was taken in the 100th minute at the end of the experiment. Enflurane produced a negative chronotropic and inotropic effect on the heart muscle. Blood pressure decreased by 40% and cardiac output by 32%. Total peripheral resistance was reduced in the 20th minute by 28% but returned to the control level towards the end of the experiment. We observed a few disturbances of cardiac rhythm and conduction. The spontaneously breathing group developed a respiratory acidosis. Within 10 minutes of discontinuing enflurane administration all parameters returned to the control levels. An obvious overdose of enflurane caused transitory convulsions in two animals. Similar symptoms are well known in humans. We prefer enflurane in the minipig since, in contrast to other inhalation anaesthetics, almost none is metabolised. This is especially important in cases of repeated anaesthesia in the same animal.

Anesthesia, Inhalation↗

Quantitative changes of membranes in rat parathyroid cells related to variations of serum calcium.

Parathyroid glands of rats were exposed to low, normal, or high serum calcium concentration by infusion of either ethylenglycol-bis-(2-aminoethylether)-tetraacetic acid (EGTA), NaCl, or CaCl2 for 90 minutes. Electron microscopic morphometry revealed that the cell volume remained constant, whereas the cell surface increased significantly after EGTA infusion and decreased significantly after CaCl2 infusion compared with parathyroid cells of NaCl-infused rats. The surface of the Golgi complex including the surrounding vesicles increased significantly after CaCl2 infusion. Significant changes were not obvious in the volume and surface of the nucleus or in the surface of the rough endoplasmic reticulum. These results suggest, first, that parathyroid hormone is released by exocytosis leading to increased cell surface within 90 minutes. Second, it is considered likely that plasma membrane constituents are retrieved by endocytosis and incorporated into the Golgi complex supporting the idea of membrane recycling.

Animals↗

[Non A, non B-hepatitis in children].

Between 1975 and 1980, 10 children with acute and 8 children with chronic hepatitis type Non A, NON B (NANB) were seen in our hospital. Parenteral inoculation was probable in 10 cases. Hepatitis NANB was diagnosed in about 11% of all children with acute viral hepatitis who were admitted over this period. Children with parenterally acquired disease were more frequently anicteric and had less pronounced transaminase elevation than "sporadic" cases. An uncomplicated outcome was observed in only three of the ten children. Two patients died from acute liver failure, chronic hepatitis developed in three other children. The 9 children with chronic hepatitis NANB are representing 17% of all patients with chronic hepatitis who were seen in our clinic between 1975 and 1980. In six children with CPH a benign course was observed whereas three children with CAH were severely ill including portal hypertension. Immunosuppressive therapy was tried in two cases without success. In children as well as in adult patients, acute hepatitis NANB apparently has more frequently a prolonged course or progression to chronic liver disease than acute hepatitis of other etiology. It seems that CPH NANB shows a similarly benign course as chronic persistent hepatitis B. CAH NANB in our patients, however, had a poorer prognosis than CAH type B.

Acute Disease↗

[Arterial vascular occlusion in penicillin allergy (author's transl)].

A nodular exanthema of the skin was observed in an 8-year-old girl. She had been treated with penicillin a few days ago because of a gastrointestinal infection. Continuation of penicillin treatment led to occlusion of larger arteries with gangrene of the forefoot. This was accompanied by septic temperatures and superinfected skin lesions. Angiologic and angiographic investigations showed a right-sided femoro-popliteal occlusion and occlusions of the arteries of the lower leg. On the left side there was spasm of the superficial femoral artery. After cessation of penicillin and high-dose steroid therapy rapid restitution occurred. Arterial spasms regressed, the occlusions remained persistent, but there was adequate collateral blood supply and ischaemic acral necroses healed. An allergic reaction of the intermediary type involving major arteries can be considered causative underlying pathology.

Adrenal Cortex Hormones↗

Surgical treatment for congenital occlusion of the inferior vena cava in its diaphragmatic portion.

This is a case report on a congenital occlusion of the inferior vena cava in its diaphragmatic part. Additionally, the proximal 10 cm within the retrohepatic portion of the vessel were highly stenotic. With exception of the vena hepatica brevis all larger hepatic veins were occluded. Correction was achieved using a 14 mm Gore-Tex (Polytetrafluoroethylene) graft, which connected the abdominal part of the inferior vena cava to the right atrium.

Adult↗

[Practical-clinical aspects in primary clearing of the upper respiratory tract in newborn (author's transl)].

There are contradictory descriptions in the literature about the methods as well as the sequence of clearing the upper respiratory tract of new-born babies. In order to clarify this problem anatomical, physiological and pathophysiological aspects of the fetal and neonatal respiratory system are described. Intrauterine asphyxia can lead to aspiration of amniotic fluid (containing meconium, squamous epithelium, lanugo hair). During delivery the fetal airway is cleared by compression of the thorax. Through suction of the mouth, throat and nose--in exactly this defined sequence--before birth of the thorax, aspiration of potentially damaging material can be prevented. The particular problem associated with meconium-steined amniotic fluid is described.

Amniotic Fluid↗

Three genes coding for subunits of the membrane sector (F0) of the Escherichia coli adenosine triphosphatase complex.

Two mutant unc alleles, unc-469 and unc-476, have been characterized as affecting a previously undescribed gene, designated uncF. The uncF gene is part of the unc operon (with the gene order being uncBFEAGDC), although some uncertainty remains as to the relative order of the uncF and uncE genes. Mutant strains carrying the uncF469 or uncF476 allele lack the 18,000-molecular-weight component of the F0 sector of the adenosine triphosphatase in the cell membrane but retain the dicyclohexylcarbodiimide-binding protein (molecular weight, 8,400). Conversely, strains carrying mutations in the uncE gene lack the dicyclohexylcarbodiimide-binding protein but retain the 18,000-molecular-weight protein in the cell membrane. Strains carrying mutations in the uncB gene have both the 18,000-molecular-weight protein and the dicyclohexylcarbodiimide-binding protein present in the cell membranes. The three proteins of the F0 portion of the adenosine triphosphatase, viz., 24,000, 18,000, and 8,400 molecular weights, became membrane associated after in vitro transcription-translation with plasmid pAN51 as template. Plasmids carrying deletions which affected the UncBFE region were isolated from plasmid pAN51 and characterized genetically. A comparison of the genes that were absent from the various deletion plasmids with the membrane-associated products formed after in vitro transcription-translation indicated that the uncB gene coded for the 24,000-molecular-weight protein and that the gene order was probably uncBFE. A correlation between length of deoxyribonucleic acid, genes present, and their products is presented in relation to plasmid pAN51.

Adenosine Triphosphatases↗

Adrenaline sensitive adenylate cyclase in human gastric mucosa.

Basal and adrenaline-stimulated adenylate cyclase (AC) was studied in biopsy specimens of the gastric and duodenal mucosa from 112 individuals. AC activities were log normally distributed. AC of fundic and antral gastric mucosa responded to adrenaline in a concentration-dependent manner, that of the duodenal mucosa did not respond to adrenaline. The degree of activation in biopsies of normal gastric mucosa was similar to that of patients with chronic atrophic gastritis or patients antrectomized according to the Billroth method. AC in biopsies from cimetidine-treated peptic ulcer patients was less sensitive to adrenaline than AC in biopsies from untreated patients. The threshold concentration of cimetidine to inhibit adrenaline-stimulated AC in vitro was 10(-6) mol/l. The data provide evidence of an adrenaline-sensitive AC in cells other than parietal cells and show an inhibitory action of cimetidine on the catecholamine-sensitive AC in the human gastric mucosa.

Adenylyl Cyclases↗

[Treatment of pains from bone metastases with 90Y (author's transl)].

For palliation of pain caused by bone metastases beta radiation isotope therapy was successful. As shown in experimental work on animals bone uptake of 90Y with its shorter half-life is high when it is administered as a citrate complex. 90Y can be eluted with high purity from a 90Sr "cow". The retention in man was found by whole-body counting to be higher than 80%. In preliminary trials on 16 patients the analgetic effect was the same as that of 89Sr. The properties of 90Y therapy are discussed.

Bone Neoplasms↗

Immunological features of preeclampsia: increased frequency of antilymphocyte antibodies, but not of immune complexes.

Using two methods for detecting circulating immune complexes (CIC)--inhibition of antibody-dependent cell-mediated cytotoxicity and solid-phase C1q assay--we were unable to demonstrate CIC in sera from preeclamptic patients and from healthy pregnant women. Antilymphocyte antibodies were found much more frequently in multiparous women suffering from preeclampsia-like disease than in healthy multiparous pregnant control patients. They were not detected in primigravida uncomplicated or preeclamptic pregnancies. It is suggested, therefore, that preeclampsia may have a different etiology in the multiparous woman than in the primigravida.

Antibody-Dependent Cell Cytotoxicity↗