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Biomedical subjects

J Robert

Publications and source records attributed to J Robert.

At least 451 records · Page 25Linked to original sources
PubMed1981

Phospholipid acyl group composition in normal and tumoral nerve cells in culture.

We have studied the fatty acid composition of total phosphoglycerides from various types of nerve cells in culture. Primary cell cultures were compared with tumoral cell strains. Glial cells exhibited no characteristic pattern when compared to neurons. Tumoral cell phosphoglycerides contained much higher levels of octadecenoic acid and lower levels of C-20 to C-22 polyunsaturated fatty acids than normal cell phosphoglycerides. This observation seems to be a general feature in tumoral cell membranes. It could be of interest in respect to the membrane fluidity of cancer cells.

Animals↗
PubMed1981

Changes in 86-rubidium uptake in erythrocytes of digoxin-treated patients, in heart failure with sinus rhythm. Relationship to clinical effects.

Previous studies have shown a significant relationship between the clinical effect of digoxin and a tissue response, namely the inhibition of 86Rb uptake by the patients' erythrocytes. In the present study, this relationship is confirmed in patients, in heart failure with sinus rhythm. The slowing of the heart rate but not the QS2 index changes correlates significantly with the 86Rb uptake inhibition.

Adult↗
PubMed1981

Digoxin in the elderly and in renal failure. Contribution of erythrocyte 86-rubidium uptake tests.

Na+,K+-ATPase activity was assessed indirectly in three groups of subjects of differing age, and in a group of patients with renal failure, by measuring the 86-rubidium uptake in the patients' own erythrocytes. The inhibiting action of digoxin on this activity was also measured in vitro. Erythrocyte 86Rb uptake was found to be lower in the elderly as was the calculated volume of distribution of digoxin. Sensitivity to the inhibiting action of digoxin increased with age. In the renal failure group 86Rb uptake was diminished and the sensitivity to digoxin was variable. This suggested that Na+,K+-ATPase activity could be one determinant of the volume of distribution of digoxin and that quantitative and qualitative changes of this enzyme could explain features of the pharmacokinetics of digoxin in renal failure and in old age.

Adult↗
PubMed1981

Study of the sensitivity of neonates to digoxin: contribution of erythrocyte 86rubidium uptake test.

In general, there is little agreement how digoxin should be used in newborn, and the results of studies in this field seem contradictory. This study attempts a quantitative assessment of the number and the sensitivity of cellular receptors for digoxin in the organism, by the in vitro measurement of erythrocyte 86Rubidium uptake in neonates compared with adults and old people. Red blood cells are first incubated with differing concentrations of digoxin, and then incubated with 86Rb. The initial level of 86Rb uptake (Rbi) is that observed in the absence of digoxin. The 50% index of captation (IC50) is the digoxin concentration in nanograms per ml at which 86Rb uptake is half Rbi. Three groups of patients were studied: Group I: 12 neonates, less than 5 days old; Group II: 11 adults (26 to 57 years old); Group III: 9 elderly people (71 to 82 years old). Rbi was significantly lower in neonates (Mean +/- SD: 25.8% +/- 3.5, P less than 0.001) and in the elderly (29.9% +/- 3.1) than in adults (36.8% +/- 4.6). IC50 was significantly lower in the elderly (12.1 ng/ml +/- 2.4) than in the adult patients (20.5 ng/ml +/- 5.5, P less than 0.001). In the newborns, values of IC50 were widely scattered (16.2 ng/ml +/- 7.2). The authors suggest that since Rbi reflects Na+, K+-ATPase activity, this activity is diminished in newborn and old people, and indicates that they have fewer cellular receptors for digoxin than adults. In the elderly, the low IC50 would imply increased sensitivity to digoxin. In neonates, the wide range of values for IC50 suggests considerable individual variation in sensitivity to digoxin. The results are consistent with the recently recommended lower dosages of digoxin in neonates.

Adult↗
PubMed1981

[Myocardial scintigraphy using technetium-99m labelled methylene diphosphonate in coronary care units. 82 cases].

Many isotopic methods have been proposed recently for the investigation of normal and diseased myocardium in ischaemic heart disease. The results of myocardial scintigraphy with Technetium 99 m marked methylene diphosphonate in the supine, left lateral and 30 degrees or 45 degrees right anterior oblique incidences are reported. A preliminary study of the tracer's fixation on diseased myocardium was performed in 18 patients. Scintigraphy every 30 minutes over a five hour period showed the optimal time for investigation to be situated between the third and fourth hour after the injection of the tracer. Seventy eight patients were then investigated; 82 scintigraphies were performed, 58 in patients with acute myocardial infarctions confirmed by the usual biological and electrocardiographic changes. A 74% sensitivity and 67% specificity were obtained with the methylene diphosphonate method. These figures varied according to the type of necrosis, subendocardial or transmural and with its extent, chronicity and degree of CPK elevation. Methylene diphosphonate scintigraphy would appear to be less sensitive and more specific for diseased myocardium than other isotopic methods. It may be carried out at the bedside and could improve the diagnosis of acute myocardial infarction when the clinical history and electrocardiographic changes are difficult to interpret.

Adult↗
PubMed1981

[Importance of bone scanning with Tc 99m in the supervision of hemodialysis patients with chronic renal failure (author's transl)].

Bone uptake of 99 m Tc diphosphonate may allow early diagnosis of renal osteodystrophy. Our study deals with 53 patients treated by repeated hemodialysis and reveals scanning abnormalities in 75% of them. Bone scanning provides information which are not visualized radiologically, especially scattered or located pulmonary calcifications (15% in our series). It is valuable in the follow-up of bone changes and is part of the necessary investigations before carrying out parathyroidectomy.

Adult↗
PubMed1981

[Combined hyperthermia, radiotherapy and chemotherapy: preliminary clinical results (author's transl)].

Results of treating superficial cancerous nodules by hyperthermia, alone or combined with radiotherapy or chemotherapy, over a period of one year, are presented. Twenty-five patients with multiple cutaneous or subcutaneous metastatic tumors were treated by 1 to 3 MHz ultrasound hyperthermia or 434 MHz microwave hyperthermia. Good local tolerance was observed, even in regions previously treated with high doses of irradiation. Regression of the tumors was assessed by comparison with unheated nodules. Two out of 11 tumors treated by hyperthermia alone, 10 out of 17 tumors treated by conventional chemotherapy combined with hyperthermia showed significant regression.

Hot Temperature↗
PubMed1981

NMR proton longitudinal relaxation times in tissues of the tumour-bearing C3H mouse studied as a function of frequency.

Because of progress in NMR imaging techniques that open the feasibility of detecting cancer by recording water protein relaxation times, it is essential to elucidate the origin of the changes of this parameter by careful studies on animals. Water proton longitudinal relaxation times were measured in vitro between 7 and 90 MHz for several tissue samples of C3H male and female mice, controls and tumor-bearing. We showed that tumor and other tissues of cancerous animals gave higher T1 values than the same tissues of controls, but that this "systemic" effect of cancer was superimposed to larger genetical T1 changes. We draw conclusions for an optimum frequency around 10 MHz, giving maximum of contrast between tumor and other tissues. According to a two-site model of water in tissues, we found the "bound" water compartment to be smaller in tumor, or, preferably, that the magnitude of the water-protein interaction was smaller there.

Animals↗
PubMed1980

[Characterization of viral RNA in Friend tumor cells having lost their capacity to produce viral particles].

Cytoplasmic RNA from Friend tumoral cells which had lost their ability to produce viral particles was analyzed for its viralRNA content. A major 32S RNA corresponding to the genome of the defective SFFV virus was detected by hybridization with a synthetic DNA complementary to the Rauscher virus genome. Very low amounts of a 34S species were also found. No 38S RNA with the size of the helper virus genome was present in the cells. It was concluded that the cessation of virus production resulted from a disappearance of the helper provirus from these cells or from a block in the transcriptional process of this provirus.

Animals↗