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Biomedical subjects

B Jung

Publications and source records attributed to B Jung.

At least 91 records · Page 5Linked to original sources
PubMed1985

A new monooxygenase product from 7-ethoxycoumarin and its relation to the O-dealkylation reaction.

The widely used fluorometric microsomal monooxygenase test for 7-ethoxycoumarin O-dealkylation was reinvestigated with regard to other possible hydroxylation products. By HPLC-analysis no beta-hydroxylation of the ethyl group and no 8-hydroxylation could be detected. Only a small percentage of 6-hydroxylation occurred, but as a new major metabolite 7-ethoxy-3-hydroxycoumarin was found in quantities depending on the microsomal preparation used. The ratio of O-dealkylation to 3-hydroxylation varied according to species, induction, buffer and pH, suggesting that different isozymes of cytochrome P450 were involved. The isozyme mainly responsible for 3-hydroxylation exhibited a great dependence on cytochrome b5 as the donor for the second electron. The fluorometric test does not include 3-hydroxylation due to the virtual absence of an emission spectrum above 450 nm.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1985

Radioprotection of the kidney with degradable microspheres. A pilot study in the dog with repeated irradiation.

The left kidney of 9 dogs was irradiated daily for three days with 300 kVp X-rays. Radioprotection was attempted in 5 of the kidneys by administration of degradable microspheres in the renal artery, immediately before irradiation. Protected kidneys received 3 X 8 or 3 X 12 Gy in midplane dose, unprotected kidneys 3 X 5.2 or 3 X 8 Gy. A protective effect due to induced hypoxia could be demonstrated in creatinine clearance, which was significantly higher in protected than in unprotected kidneys at 7 - 13 weeks after irradiation.

Animals↗
PubMed1984

Morphologic and histochemical studies on the differing radiosensitivity of ductular and acinar cells of the rat submandibular gland.

The submandibular glands of male rats were exposed to 50 Gy X-irradiation as a single dose, with or without pre-treatment with either alpha-adrenergic agonists (noradrenaline, phenylephrine) or a cholinergic antagonist (atropine). The effects were analyzed by morphometric, cytochemical and biophysical methods. When X-irradiated without drug pre-treatment, many serous epithelial cells of the intralobular convoluted ducts displayed morphologic evidence of irreversible radiation damage, in contrast to neighbouring mucous and other cells which were unaffected. The effect was maximal 96 h after irradiation. Serous cells from animals irradiated after pre-treatment with atropine showed much more wide-spread injury than those of animals exposed to X-irradiation only. In contrast , serous cells suffered considerably less damage if their secretory granules had been depleted 1 or 2 h before irradiation with either noradrenaline or phenylephrine. Other epithelial cells showed no modulation of their slight radioresponsiveness by these drugs. The observations were substantiated by morphometry of three cell types: (a) mucous cells, (b) non-granulated serous and intralobular striated duct cells, and (c) granulated serous cells. The findings suggest that the striking radiosensitivity of salivary gland serous epithelial cells is linked to their content of secretory granules. These granules are rich in heavy metals, as demonstrated cytochemically with the sulphide silver method (SSM). Using particle-induced X-ray emission ( PIXE ) spectroscopy, the principal metals were shown to be Zn, Mn and Fe. It is conceivable that membranes which enclose organelles rich in metals with the ability to form redox systems (e.g. Fe2+ in equilibrium Fe3+) show enhanced sensitivity to radiation damage due to the metal-catalyzed induction of lipid peroxidation by ionizing radiation. Disruption of secretory granules would be expected to release lytic enzymes into the cell sap, resulting in autolysis. This hypothesis is supported by the findings that atropine--which increases the number of granulated serous cells--enhances radiosensitivity, while noradrenaline and phenylephrine--which cause degranulation of serous cells--decrease radiosensitivity.

Animals↗
PubMed1984

Evidence for a propulsive function of the migrating myoelectric complex in rats.

In order to investigate the relation between myoelectric activity and the transport of small bowel luminal contents, recordings of migrating myoelectrical complexes (MMCs) were combined with studies of the propulsion of a bile-excreted radioactive test substance. At laparotomy, rats were provided with three pairs of bipolar electrodes, sewn to the seromuscular layer of the small bowel 15, 30 and 45 cm distal to the pylorus. After recovery for 1 week MMCs were recorded with the animal fasted for 18 h and in light barbiturate anesthesia. Concurrently, the bile-excreted radiopharmaceutic, 99mTc-Solco-HIDA, was infused intravenously. At the end of the experiment the rats were sacrificed and the distribution of 99mTc activity was recorded from the excised bowel specimen. In 12 animals with a typical MMC activity recurring every 20 min, the small bowel radioactivity was distributed into discrete portions, separated by fairly long empty segments. In 6 animals the experiments were terminated when an MMC activity front had reached one of the electrodes and in all, a portion of radioactivity was found to be located immediately distal to the position of that particular electrode. 6 control animals were killed when about 10 min had elapsed since the MMC front passed one of the electrode sites. In all these cases the electrode position was found to correspond to empty bowel segments. These data obtained from animals with permanent electrodes but an otherwise intact small bowel strongly support the notion that MMCs result in propulsion of luminal contents.

Animals↗
PubMed1984

Variance measurements with two semiconductor dose detectors.

Variance measurements were performed with pairs of semiconductor detectors of different ionization volumes in continuous and pulsed radiation fields. By a statistical analysis the relative variance of the detector was separated from that of the accelerator. The relative variance of the detector signal was shown to be correlated to the detector volume and to the dose per pulse. From the measurements the number of events per pulse within the detector volume was estimated and the number of pulses needed to have a reading with a given precision was estimated.

Cobalt Radioisotopes↗
PubMed1983

Ellipsoidal body phantom for evaluation of CT scanners.

A phantom for study of uniformity, artifacts from dense structures, and consistency in pixel values was constructed. On-site studies of eight computed tomographs belonging to the second, third, and fourth generations showed that the phantom was appropriate for such measurements. The results indicate certain inherent shortcomings in some of the present designs.

Humans↗
PubMed1983

Effects of a fatty meal on small bowel propulsion in intact and vagotomized rats.

The mechanisms by which a fatty meal alters small bowel motility was studied in rats. The fatty meal (3 ml soya bean emulsion) was infused via a permanent gastric catheter and, simultaneously, a bile-excreted radiopharmaceutic, via a central venous catheter. After infusion for 1 h the radioactivity along the small bowel was measured from the excised bowel specimen. In fasting animals an 'interdigestive' pattern was found, characterized by the distribution of small bowel contents in well-separated portions. After administration of the fat meal, a different ('postprandial') type of transit was found, characterized by a continuous distribution of radioactivity along the small bowel. In vagotomized animals the chosen fat meal did not induce a postprandial pattern but instead the small bowel retained its interdigestive transit mode. However, in intact animals pretreated with atropine or naloxone, the fatty meal intragastrically resulted in an ordinary postprandial transit pattern. Thus, the effect of the surgical vagotomy seems to be mediated by interruption of noncholinergic, nonenkephalinergic neurons.

Animals↗
PubMed1983

Effect of feeding on the pattern of small bowel transit in the rat.

The effect of feeding on the small bowel transit pattern was studied in rats provided with a central venous catheter and a permanent gastric catheter. Solutions of glucose, amino acids or lipids were administered via the gastric catheter for 20 minutes (2 or 10 ml X h-1), while 99Tcm-Solco-HIDA, a bile-excreted radiopharmaceutic, was infused intravenously for 1, 3 or 5 hours. At the end of the intravenous infusion, the gastrointestinal tract was excised and the radioactivity along the specimen was measured. In rats given no gastric feeding, the transit of small bowel contents occurred in well separated portions and the gut segments between the portions were free from radioactivity. With gastric feeding at the higher rate, examination of the small bowel contents after 1 hour showed continuous distribution along the gut, without apparent peaks or empty regions. When examined at 3 and at 5 hours, the small bowel seemed to have resumed its interdigestive pattern. The transit of chyme in the early postprandial period thus occurs in a manner distinctly different from the interdigestive transit pattern. The observations agree closely with electromyographic studies showing postprandial elimination of cyclic recurring activity.

Amino Acids↗
PubMed1982

Effects of neurotensin on small bowel propulsion in intact and vagotomized rats.

The effects of intravenous infusion of neurotensin on small bowel motility was studied in conscious rats. During 1 h a standardized test meal of glucose, polyethyleneglycol (PEG) 3000, phenol red and 125I-labelled polyvinylpyrrolidone was administered via a permanent gastric catheter and simultaneously the bile-excreted radio-pharmaceutic 99Tcm-Solco-HIDA was infused intravenously. Immediately after the infusions the gastrointestinal specimen was excised and examined for distribution of radioactivity. Both doses of neurotensin (0.1 and 0.3 microgram . kg-1 . h-1) resulted in an increase in the neurotensin-like immunoreactivity (NTLI) of plasma to levels similar to that found after a fatty meal. Concurrently the small bowel transport pattern was changed from an interdigestive state to one similar to that found after a meal. In animals not receiving the gastric test meal, neurotensin (0.1-0.5 microgram . kg-1 . h-) had no effect on motility. Infusion of the gastric test meal alone did not change the interdigestive motility or the NTLI value. This indicates that the presence of gastric infusates potentiates the effect of neurotensin on small bowel motility. The motility response to neurotensin did not differ between intact and vagotomized animals. This contrasts to earlier findings that the small bowel motility response to a fatty meal is dependent on intact vagal function. Thus, a difference in the mechanism responsible for the motility responses between a fatty meal and neurotensin exists. In view of this finding it seems reasonable to assume that neurotensin cannot be the only factor responsible for the shift in motility found after a fatty meal.

Animals↗
PubMed1982

Histopathological malignancy grading and familiality in an unselected series of 1303 women with breast carcinoma.

Histopathological characteristics were studied in 1303 women consecutively diagnosed as having breast cancer. They comprised a total material from a defined geographical area. The significance and distribution of malignancy grades according to Ackerman's system were evaluated in this unselected material. Their relationships with other morphological characteristics and with the occurrence of axillary node metastases with or without periglandular growth were appraised. These characteristics were also related to the familial occurrence of breast cancer. The distribution according to the Ackerman grading was: type I 39 cases (3%), type II 75 (6%), type III: 2 95 (7%), type III:1 793 (61%) and type IV 301 cases (23%). The degree of differentiation (partly by definition) correlated highly significantly with the malignancy grading. Axillary lymph nodes were available for histopathological examination in 844 cases. In malignancy types I and II there were no lymph node metastases, in type III:2 2%, in III:I 40% and in type IV 77%. Periglandular growth was found only in type III:I and IV--in 9 and 59%, respectively. Familial occurrence of breast cancer was confirmed in 19% of the patients. Familial and non familial cases did not differ significantly with respect to the distribution of malignancy grades, degree of differentiation, grade of cell polymorphism or frequency of lymph node metastases.

Aged↗
PubMed1982

Studies on oesophagitis--no evidence for pyloric incompetence as a primary etiological factor. a scintigraphic study with 99Tcm-Solco-HIDA.

Duodeno-gastric bile reflux was studied by means of a non-invasive scintigraphic technique in 15 patients with symptomatic oesophagitis. The fate of an intravenously administered, bile-excreted radiopharmaceutic, 99Tcm-Solco-HIDA, was followed with a gamma camera. In 12 patients with an intact pylorus and in one patient operated upon by truncal vagotomy and pyloroplasty no evidence of bile reflux to the stomach was found. One of two patients earlier operated upon by a Billroth I gastrectomy had scintigraphic evidence of a severe bile reflux. We conclude that duodeno-gastric bile reflux is uncommon in patients with hiatal hernia and oesophagitis, and hence that normally pyloric incompetence is of minor importance for the development of this disorder.

Adult↗
PubMed1981

Fine structure and function of interrenal (adrenocortical) cells of dexamethasone-treated trout (Salmo fario L.).

The ultrastructure of the interrenal (adrenocortical) cells of trout (Salmo fario L.) was studied after dexamethasone treatment. A procedure for identifying and isolating interrenal tissue fragments from the surrounding head kidney tissue prior to their preparation for electron microscopy is described. The peripheral plasma cortisol concentrations were measured in order to evaluate the steroidogenic activity of this tissue. The interrenal cells of control animals contain numerous mitochondria with tubular cristae, and a well developed and highly organized smooth endoplasmic reticulum (SER). The scarcity, or absence, of lipid droplets contrasts markedly with the abundance of SER. Treatment with dexamethasone results in a decrease steroidogenic activity of the interrenal cells, as indicated by the fall in plasma cortisol concentrations. The interrenal cells are small, but still contain numerous mitochondria. The SER is poorly developed, but masses of densely intermeshed smooth cisternae subsist. Lipid droplets do not accumulate in these cells; this peculiarity is discussed in connection with the virtual absence of liposomes in teleost interrenal cells.

Adrenal Glands↗
PubMed1981

Perceptibility of experimental and clinical lesions in the CT image with and without image processing.

The Ohio-Nuclear Delta 50 FS whole-body CT scanner and image filtering programs FI and SP:SMOOTH provided with the equipment were used to investigate how the perceptibility in the CT image of artificial lesions in a phantom and of liver lesions in patients was influenced by different reconstruction diameters, radiation doses and section thicknesses and by image filtering and different conditions of viewing. The perceptibility of both artificial and clinical lesions was considerably improved, especially in scans with a low radiation dose, when optimum viewing conditions and image filters were used.

Filtration↗