[Etiology of hypercalciuria in recurrent kidney calculi].
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Calcium↗
Biomedical subjects
B Jung
Publications and source records attributed to B Jung.
[Synthesis of some 4-oxo-3,4-dihydroquinazoline-3-carboxylic acid derivatives].
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Carboxylic Acids↗
Cytoplasmic effects of X-irradiation on cultured cells in a nondividing stage. 3. Alterations in plasma membrane motility.
Cultured, density-dependent growth inhibited human glia cells were exposed to X-radiation, generated by an 8-MeV linear accelerator, at a dose of 200 Gy. Phase contrast microscopy, time-lapse cinemicrography and scanning electron microscopy showed the irradiated cells to have increased ruffling activity of plasma membranes and enhanced macropinocytosis with a maximum approximately 24 hours after irradiation. "Atypical" central ruffles arising from the upper cell surface were demonstrated on some irradiated cells. The turnover of plasma membranes was supposed to be increased in the irradiated cells resulting in the formation of the observed branched, thread-like cells. The diminished cell surface area was believed to result from an unbalance between degradation and renewal of the plasma membranes in the irradiated cells.
Cell Line↗
Radiation response modified by degradable starch microspheres. Experiments on the rat's foot.
Skin reaction in the rat's foot was used as an experimental method to evaluate the protective potential of profound temporary hypoxia against roentgen radiation produced by a linear accelerator. Hypoxia was induced by intraarterial injection of degradable starch microspheres. The irradiation dose needed to evoke a certain reaction in the hypoxic feet was 2.0 times the dose giving the same reaction in a control group. The results point towards a new technique of inducing local hypoxia in healthy tissues which need to be protected in an irradiation field.
Animals↗
Mucosal protection during irradiation of exteriorized rat ileum. Effect of hypoxia induced by starch microspheres.
Transient hypoxia induced by intra-arterial injection of degradable starch microspheres was used for protection of exteriorized segments of the rat ileum. Microscopic evaluation of the injury to the mucosa gave a dose modification factor of 0.44 +/- 0.04, which corresponds to an oxygen enhancement ratio of 2.30. A similar factor was also found from measurements of the mucosal weight. No significant development of mucosal oedema could be demonstrated, neither in protected nor in non-protected segments.
Animals↗
Abdominal radiation response modified by hypoxia after intra-aortal injection of starch microspheres. Experiments in the rat.
Degradable starch microsphers were injected in the aorta of rats above the level of the superior mesenteric artery 5 min before roentgen irradiation of the abdomen. The local hypoxia, induced by the spheres, was found to have an appreciable protective effect. The dose modification factor was estimated as 0.7.
Abdomen↗
Propulsion and mixing of small bowel contents during exogenous gastrin infusion. An experimental study in rat.
The effect of intravenous infusion of Synthetic Human Gastrin I (SHG) on the propulsion and mixing of small bowel contents was studied quantitatively in conscious rats. Radioactive test substances were infused continuously through a permanent duodenal catheter for totally five hours. Two differently labelled, but otherwise identical, test substances were used and one of them (125I-PVP) was infused during the first three hours, the other (131I-PVP) during the remaining two hours. The activity distribution of each isotope along the excised bowel specimen was measured immediately after the end of the infusion. The bowel length passed by the transition point between the nuclides and the region of overlap in the border zone between them were taken as measures of propulsion and mixing, respectively. A significant increase of the serum gastrin level during infusion of SHG was verified by radioimmunoassay. The total small bowel transit time was significantly prolonged during gastrin infusion secondary to a retarded propagation velocity in the distal small bowel. The slower transport rate during gastrin infusion was coupled to a significant increase of the mixing of small bowel contents. These changes in small bowel motility were not apparently due to a concomitant increase of gastrict acid secretion, since pretreatment with a potent H2-receptor blocker, cimetidine, did not abolish them.
Animals↗
Propulsion and mixing of small bowel contents in rat during varied levels of endogenous gastrin.
The propulsion and mixing of small bowel contents were studied in conscious rats 14 days after antral resection, antral exclusion and gastroentero-anastomosis in order to evaluate the influence of hypo-, hyper- and normogastrinemia, respectively, on the net result of small bowel muscular activities. The quantitative measures of propulsion and mixing did not differ significantly between the groups. There was, however, a significant correlation between high serum gastrin and increased intestinal mixing after antral exclusion and gastroentero-anastomosis. This finding supports earlier studies on gastrin effects on the small bowel obtained by exogenous gastrin infusion.
Animals↗
Gastric emptying in duodenal ulcer patients before and after truncal vagotomy with pyloroplasty and parietal cell vagotomy.
The gastric emptying of a liquid test meal containing 99Tcm-sulphur colloid was studied with a gamma camera in 24 duodenal ulcer patients. Studies were made before surgery, randomly chosen between truncal vagotomy with pyloroplasty and parietal cell vagotomy, and six weeks and one year after. Large variations in the emptying patterns were observed both between patients and in the same patients. No consistent change in the distribution of patterns were found between the three observation times and between the two surgical procedures. An initial rapid emptying was found in several studies and was observed both before and after operation and did not seem to be related to type of surgical procedure or to individual patients. The method applied did not allow a detailed study of this initial phase, which appears to be of a higher significance for the over-all emptying characteristics than the late exponential emptying, on which earlier investigators have been focused.
Adult↗
Simultaneous measurement of the propulsion and mixing of small bowel contents in the rat.
A method is presented for the simultaneous measurement of propulsion and mixing of small bowel contents in conscious rats. Through a permanent duodenal catheter two differently labeled test substances (125I-PVP and 131I-PVP) were infused continuously one after the other. The radioactive label was changed once during the total infusion period of 5 hours. Studies were performed in six groups of animals which differed with respect to time for interchange of test substance. At the end of the total infusion period the border zone had travelled to six different locations in the small bowel. The animals were then killed and the two radioactivities were recorded from the excised bowel specimen. The resulting activity densities along the small bowel were peaky and the overlap between the two labels in the border zone was minute, indicating that the intestinal contents were transported in isolated portions with only minor exchange of luminal contents between adjacent regions. The transport apparently proceeded steadily in a mainly aboral direction with no indications of abrupt changes in transport velocity.
Animals↗
Cytoplasmic effects of X-irradiation on cultured cells 2. Alterations in lysosomes, plasma membrane, Golgi apparatus, and related structures.
Topoinhibited human glia cells in vitro were exposed to X-radiation generated by an 8-MeV linear accelerator at a dose of 20,000 rad. Transmission electron microscopy of irradiated cells at intervals varying between 30 min. and 5 days following irradiation revealed alterations mainly in the plasma membrane and the lysosomal vacuome. Increased ruffling of plasma membranes, augmented endocytosis and extensive intracellular autophagy developed within 24 hours after irradiation. The implications of the plasma membrane alterations are discussed, and a tentative model covering possible mechanism involved in the development of autophagic vacuoles is presented. The possibility is entertained that alternative mechanism may be operative during the formation of the autophagic vacuole in irradiated glia cells. The origin of the isolation membrane appears to be (a) preexisting lysosomes; and (b) flattened vacuolar cytoplasmic elements.
Cell Membrane↗
Cytoplasmic effects of x-irradiation on cultured cells in a nondividing stage. 1. Establishment of an experimental model.
The investigation was initiated with the aim of establishing a suitable experimental model with respect to mode of radiation and radiation dose for elucidating morphologically the sequential development of radiation induced damage of interphase cells (human glia cells in vitro). Adequately defined and reproducible cellular changes were obtained using X-radiation generated by an 8 MeV linear accelerator at a dose of 20,000 rad. The cellular alterations were studied in the light microscope and by scanning and transmission electron microscopy. The most conspicuous changes--first appreciable about 5 hours after irradiation--occurred in the lysosomal vacuome, and the plasma membrane and associated structures.
Cell Line↗
[Coxsackie B3 epidemic in a neonatal ward].
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Antibodies, Viral↗
The use of 125I-labelled fibrinogen for determination of fibrin trapping in the lungs in patients developing the microembolism syndrome.
The microembolism syndrome occurred in four patients out of a series of 15 patients with multiple injuries who were considered to run a risk of developing this syndrome. These four patients showed signs of fibrin trapping in the lungs, as demonstrated by the use of 125I-labelled fibrinogen and external detection over the lungs. It is, therefore, considered that this method can be used for diagnosing the microembolism syndrome. The fibrin trapping occurred at the onset of the progressive respiratory insufficiency. The time relation between the uptake of fibrin and the onset of the progressive respiratory insufficiency supports the theory of a causal connection between fibrin and pulmonary damage. Measurements of different coagulation and fibrinolysis factors in the blood were not able to discriminate between patients who developed the microembolism syndrome and those who did not.
Adolescent↗
Perception of simulated lesions in the lung.
The detectability of phi 20 mm, disk-shaped objects on a normal chest film was investigated at viewing distances of 0.3, 1.0 and 3.0 m. Objects with a tapered border were found to be best perceived at longer distances. The photpgraphic density difference between object and background yielding a 50% detection probability was found to increase from 0.025 to 0.060 when the outer gradient zone of the object increased from 0.8 to 4.0 mm.
Absorptiometry, Photon↗
Cell kinetic approach to optimising dose distribution in radiation therapy.
A simple tumour-cell radiation-response model was coupled to a dose-calculation routine and applied to a clinical situation in radiation therapy. The dose distributions resulting from various settings of two radiation fields, as well as the tumour response under various assumptions regarding sensitivity and distribution of tumour cells, were calculated automatically. The probability of zero surviving tumour cells after 30 fractions was taken as a measure of goodness of the dose distributions and was found to vary rather smoothly over the parameter intervals considered. For some parameters a distinct optimum was found, rather insensitive to different assumptions regarding cell response. A tolerance factor for healthy tissue, based on a dose-volume relationship, was also considered. It is concluded that a cell kinetic approach to automatic optimisation of field parameters in external radiation therapy might be realistic both from computional and economic points of view.
Cell Survival↗
11C and 15O induced in the mouse by 175 MeV protons.
The total production of 11C, 13N and 15O in the mouse by protons with a mean energy of about 175 MeV was found to be 8 200, 1 500 and 14 000 nuclei per g-rad, respectively. About 40 per cent of the total induced 11C activity was eliminated through expiration and about 2.5 per cent with the urine during the first hour after irradiation. The expired gas contained 11CO and 11CO2 in the ratio 2/1. The urinary 11C activity was bound to several compounds, the chemical nature of which was not established. The 15O activity behaved as H2O and was found not to be eliminated from the body during the short observation time available. The additional, fractional, integral radiation dose due to decay of induced nuclides is less than 0.1 per cent, and can be neglected since no accumulation to any small organ was seen. Sensitive means for an estimate of integral dose based on the induced nuclides would be the detection of 11CO activity in expired gas or in blood.
Animals↗
Errors and uncertainties in external radiation therapy. A system analysis with a cell kinetic model.
The relative importance of accurate knowledge and control of various biologic and physical factors in external radiation therapy was estimated with a simple cell kinetic treatment response model for a simulated tumour therapy situation. A set of parameter values was chosen for a reference case so that the calculated probability of zero surviving tumour cells was about 0.5. The parameters were varied, one at a time, over a range that was considered representative with respect to uncertainty in dose calculation, dose delivery and the description of the pertinent patient data. Also parameters in the cell kinetic model were varied. The calculations demonstrated a strong influence on the number of surviving cells from even moderate changes in the parameters which affect the tumour dose. Predictions with regard to curability are heavily dependent on the reliability of the biologic parameters in the model.
Cell Survival↗