Search PubMed⌕ Search

Biomedical subjects

J Mai

Publications and source records attributed to J Mai.

At least 55 records · Page 3Linked to original sources
PubMed1986

[New methods in the radiotherapy of bronchial carcinoma. Endobronchial small-field irradiation using the iridium-129 high-dose afterloading technic in combination with the neodymium-YAG laser].

106 patients with inoperable malignant tumours constricting the central bronchial tree underwent endobronchial small-field radiotherapy with iridium-192 at high dose between June 1983 and September 1985. Treatment was performed using the computer-guided after-loading technique and a flexible bronchoscope under local anaesthesia. In complete occlusion of a bronchus by the tumour, a neodymium YAG-laser was applied (57 patients) to allow insertion of the after-loading probe. Endoscopy showed tumour regression in 75% of the patients, accompanied by clinical improvement. Pulmonary function tests, arterial blood gas analyses and pulmonary perfusion scans yielded a highly significant improvement of data after treatment. The procedure also proved effective upon exhaustion of external radiation. Apart from its positive palliation, endobronchial small-field radiotherapy using high doses of iridium-192 also has a curative effect, thus opening up a new approach to the therapy of advanced bronchial carcinoma.

Aged↗
PubMed1985

[New possibilities in radiotherapy of endobronchial tumors using the afterloading method in combination with laser technics].

New possibilities for radiotherapy of bronchial carcinomas are provided by the combined application of the recently introduced afterloading method used hitherto in the treatment of stenosing processes of bronchial carcinomas and the neodyme-YAG laser which opens the stenosis in such a manner that the afterloading probe can be inserted. This new method allows to perform without complications or disadvantages further combined therapies such as percutaneous irradiation (telecobalt, linear accelerator or betatron). An irradiation scheme leading to a decisive tumor regression can be established due to the fast reventilation of the lung obtained by both methods. Surprisingly, three patients could be submitted despite the small-field radiotherapy to rather important lung operations such as lobectomy and pneumonectomy which were performed without complications or disadvantages. The patients were not operable without laser and afterloading therapy. This method was applied several times in the treatment of other diseases such as oesophageal cancer and stenosing cancer of the antrum. In these cases, a normal ingestion due to tumor regression was obtained rapidly.

Brachytherapy↗
PubMed1983

Prostaglandins and thromboxane: tert.-butyldimethylsilyl ethers as derivatives for their analyses by gas chromatography-mass spectrometry-selected ion monitoring.

tert.-Butyldimethylsilyl ethers of eighteen prostaglandins (PGs) and thromboxane have been analyzed by combined packed-column or fused-silica capillary gas chromatography-mass spectrometry (GC-MS). Except for thromboxane B2 and PGs of the 3 series the [M - 57] ion, the loss from the molecular ion of the tert.-butyl radical, is generally the major peak in the spectra of PGs. This high abundance of large fragments provides suitable criteria for the employment of these derivatives in GC-MS selected ion monitoring for rapid quantity estimation of PGs from biological samples. PGs from rat stomach fundus were rapidly quantitated in a single chromatogram using this procedure.

Animals↗
PubMed1982

Determination of prostaglandins and thromboxane as their pentafluorobenzyl-trimethylsilyl derivatives by electron-capture gas chromatography.

The optimization of the parameters affecting the chromatographic properties and separation of prostaglandin pentafluorobenzyl derivatives by gas chromatography using electron-capture detection is described. The effects of composition and flow-rate of carrier gas, temperatures of detector and column, and nature of stationary phases on the detector response to different pentafluorobenzyl (both oxime and ester) trimethylsilyl ether derivatives of prostaglandins were systemically examined. The stability of some selected prostaglandin derivatives at -20 degrees C was also determined. After standardizing these parameters, prostaglandins and related compounds from biological samples, e.g. semen, rat aorta, dog serum and trout gill were successfully analyzed. Identification of prostaglandins was confirmed by gas chromatography-mass spectrometry.

Animals↗
PubMed1982

Dietary trilinoelaidate: effects on metabolic parameters related to EFA metabolism in rats.

To study the effects of dietary trilinoelaidate (tt18:2) on metabolic parameters, as they relate to essential fatty acid metabolism, a diet containing "adequate" linoleic acid with incremental isocaloric ttl8:2 supplementation was formulated. This diet was fed to rats for 11 weeks and oxygen (O2) consumption, insensible water loss (IWL), growth parameters and liver fatty acid composition evaluated at specified time intervals. The results showed that while an essential fatty acid deficient diet (hydrogenated tallow) increased IWL and decreased body weight gains, O2 consumption remained unaltered. Dietary tt18:2, while accumulating in liver lipids, apparently inhibiting delta 6 desaturase, as evidenced by 18.2/20.4 ratios, did not alter O2 consumption of IWL. At the highest level of tt18:2 fed (2.5 weight percent of dietary fat) there was a noticeable decrease in body weight gains by the 11th week; organ weights, however, were not affected. While the increased consumption of dietary trans fatty acids has raised questions regarding their potential biologically detrimental effects, the present study indicated that gross metabolic alterations related to classical essential fatty acid deficiency symptoms are not precipitated in the rat by tt18:2 levels comparable to those consumed in a normal human diet.

Animals↗
PubMed1981

Extraction and purification of prostaglandins and thromboxane from biological samples for gas chromatographic analysis.

An efficient extraction procedure for the isolation of prostaglandins (PGs) from biological samples for their subsequent quantification by gas chromatography-electron capture detection (GC-ECD) is described. PGs were extracted from lung, kidney, spleen and stomach fundus into ethyl acetate at different pHs. The highest recovery and least extraction of contaminating pigments was obtained at pH 4.5. Pigments and other contaminants are removed by thin layer chromatography using a solvent system chloroform-isopropyl alcohol-ethanol-formic acid (45:5:0.5:0.3). The isolated PGs were determined by GC-ECD after appropriate derivatization. The overall recovery of PGs using this procedure is 60%.

Animals↗
PubMed1981

Metabolism of trans fatty acids with emphasis on the effects of trans, trans-octadecadienoate on lipid composition, essential fatty acid, and prostaglandins: an overview.

Information concerning the metabolism of trans isomers of dietary unsaturated fatty acids is presented. Dietary trans-octadecenoic and trans,trans-octadecadienoic acids are apparently absorbed, activated, oxidized, and acylated into ester lipids much like saturated fatty acids although differences have been observed with regard to their metabolism by different organs. Because of the important role of linoleic acid as the principal precursor of cyclic endoperoxides, prostaglandins and leukotrienes, the potential deleterious effects of trans isomers of this acid are discussed. High levels of dietary trans,trans lineoleate can impair delta 6 desaturase activity and decrease prostaglandin production in rats on experimental diets.

Animals↗
PubMed1980

Prostaglandin E1 and E2 in bovine semen: quantification by gas chromatography.

Prostaglandins PGE1 and PGE2 extracted from bovine semen, purified via silicic column chromatography were quantified by gas chromatography as their methoxime methyl ester trimethylsilyl ether derivatives. The PGE2 and PGE2 concentrations of 19 bovine semen samples ranged from 395 +/- 225 and 487 +/- 407 ng/ml, respectively. A constant 1:1 ratio between PGE1 and PGE2 was observed. There was not relationship between PGE and sperm motility, but high sperm counts were generally associated with decreased PGE levels. The direct precursors of PGE1 and PGE2, i.e. 20:3n6 and 20:4n6, occurred in low concentrations compared to other related unsaturated fatty acids, i.e. 18:2n6 and 22:5n6 of the n-6 family.

Animals↗
PubMed1979

Prostaglandins and their precursors in tissues from rats fed on trans, trans-linoleate.

Feeding trans,trans-9,12-linoleate to rats as 50 and 100% of the dietary fat decreased the concentrations of n-6 fatty acids, i.e. 18:2, 20:3 and 20:4, in heart, kidney, lung, adipose tissue and platelets of rats. The concentrations of prostaglandin products prostaglandins E1, E2 and F2 alpha in serum were significantly decreased in rats receiving high concentrations of dietary trans, trans-linoleate.

Animals↗
PubMed1979

Mode of action of dantrolene sodium in spasticity.

The mode of action of dantrolene sodium was studied in 11 multiple sclerosis patients with spastic paresis of the legs by measurements of changes in electromyographic and mechanomyographic proprioceptive reflex responses and in voluntary power. Dantrolene sodium 0.5 mg per kg body weight given intravenously clearly reduced monosynaptic reflex twitch tension, but voluntary power only moderately so. The electromyographic reflex responses were unchanged or slightly increased. The mode of action of the drug on spindle function is discussed on the basis of the present findings and the literature. It is concluded that dantrolene sodium does not reduce spindle stretch sensitivity, but probably reduces activity in group II and tonic 1a afferent fibers.

Dantrolene↗