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Biomedical subjects

Y Rolland

Publications and source records attributed to Y Rolland.

At least 109 records · Page 6Linked to original sources
PubMed1990

Contribution of MRI to the diagnosis and post-therapeutic monitoring of brain stem tumours.

MRI has become indispensable to the positive diagnosis of brain stem tumours which develop preferentially in young people. The prognosis of these tumours, especially infiltrating gliomas, being relatively sombre, it is important to make a precise morphological diagnosis of the lesions (increase in size, signal abnormalities) which will help both neurosurgeons and radiotherapists. As regards post-therapeutic monitoring, MRI with gadolinium contrast injection is harmless and will make it possible to follow these patients regularly and to detect recurrences.

Adolescent↗
PubMed1989

Decreased incorporation of glucose into lipids and increased lactate production by adipose tissue after long-term treatment of rats with D-fenfluramine.

Male rats were treated with ten daily doses of 10 mg of D-fenfluramine/kg. Body weight decreased after days 1 and 2, but thereafter the weight gain paralleled that of the control rats. After the tenth injection there were decreases in the weights of the epididymal fat pads, their fat content, and the average size of the adipocytes after collaginase digestion. The rate of glucose uptake by incubated pieces of adipose tissue was maintained after D-fenfluramine treatment, and the production of lactate increased. The incorporation of glucose into fatty acids by adipose tissue pieces decreased by 65-74% after treatment with D-fenfluramine. This effect was not reversed by adding insulin or phenylisopropyladenosine to the incubations. D-Fenfluramine also decreased the incorporation of glucose into glyceride-glycerol, but this effect was less pronounced than that for fatty acid synthesis. Direct addition of D-fenfluramine to the incubation inhibited lipid synthesis from [14C]glucose but only at drug concentrations above 1 mM. It is concluded that the treatment of rats with D-fenfluramine modifies the metabolic balance of adipose tissue so as to direct glucose metabolism away from lipid synthesis and towards lactate production. This could be a significant mechanism in the overall loss of adipose tissue mass caused by the administration of D-fenfluramine.

Adipose Tissue↗
PubMed1989

Promotion of micrometastasis proliferation in a rat rhabdomyosarcoma model by epidermal growth factor.

Using a rat rhabdomyosarcoma 9-4/0, we investigated the role of epidermal growth factor (EGF) in tumor dissemination. In vitro, we detected high-affinity EGF receptors on tumor cells and stimulation of their proliferation by EGF. When injected iv, EGF-pretreated cells demonstrated an increased capacity to form lung colonies and to invade lymphatic tissue. In vivo, EGF treatment led to increased metastatic spread of subcutaneous tumors. When primary tumors were ablated, and the treatment was given from the time of graft until ablation (seeding step), no effect on metastatic spread was noticed. When treatment was given from the time of ablation until death (growth step), EGF increased the number of lung metastases and of invaded lymph node sites.

Animals↗
PubMed1989

Possible connections between stress, diabetes, obesity, hypertension and altered lipoprotein metabolism that may result in atherosclerosis.

This review has discussed some metabolic and endocrine changes that can be associated with a stress type of metabolism, diabetes, obesity, hypertension, smoking and the consumption of diets rich in fat and refined sugar, or poor in ascorbate. These are some of the risk factors associated with premature atherosclerosis, coronary thrombosis and stroke. It has been proposed that an increased control of metabolism by the 'stress' or counter-regulatory hormones, relative to insulin, is a common feature of these risk factors. Particular emphasis was placed upon the action of the glucocorticoids which can produce insulin insensitivity, leading to hyperglycaemia, hypertriglyceridaemia, hypercholesterolaemia and hyperinsulinaemia. Furthermore, glucocorticoids can decrease energy expenditure and, together with insulin, promote energy deposition. These observations provide a partial explanation for the metabolic changes that can accompany the risk factors and clarify why they interact in promoting atherosclerosis.

Arteriosclerosis↗
PubMed1988

[Disk hypodensity and disk herniation].

The authors report the case of a patient with a herniated lumbar disk and bacterial meningitis. CT scan showed central disk hypodensity at the hernia level, whilst full cytological and bacteriological study of the disk following surgery revealed no evidence of spondylodiscitis. The problem was thus that of consequences of "degenerative" events related to the herniation. Central or peripheral disk hypodensity must in no case be considered as specific of discitis when there is a concomitant disk herniation.

Aged↗
PubMed1988

Effect of diosmin upon red blood cell deformability and osmotic fragility. Relationship with lipid content.

Rats were treated by ingesting forcibly 2 ml of a suspension of four different doses (100, 200, 300 and 400 mg/kg) of diosmin in carboxymethylcellulose (CMC) and were killed immediately or after 3 or 6 hours of fasting. Animals treated by CMC only in a similar way (gavage) exhibited a fall in red blood cell (RBC) membrane cholesterol and an increase in RBC rigidity at the third hour while osmotic fragility remained stable. Diosmin treatment opposed the rise in RBC rigidity evoked by the gavage and induced a dose-dependent decrease of the RBC membrane cholesterol over phospholipid ratio.

Animals↗
PubMed1987

Experimental animal models of eating disorders. Recent pharmacological studies.

Until recently, the amount of standardized laboratory food eaten--during a short period of time--by starved young and lean animals was the only parameter used to determine the effects of drugs on feeding behaviours. Now with the introduction of recent physio-pathological concepts and new behavioural designs the information obtained from pharmacological studies is much more elaborate. It concerns not only the ingestive behaviours but also the peri-prandial behaviours. It gives specific indications on how the effects of different drugs may be affected by changes in the "milieu intérieur" and by the characteristics of environmental factors. Different experimental models are described; results obtained with these models are discussed.

Animals↗
PubMed1987

[Severe and extensive algodystrophies and malignant tumors. Apropos of 4 cases].

The authors report on 4 cases of particularly severe and extensive reflex neurovascular dystrophy, whose clinical course was marked by the onset of a malignant tumor, without any sign of improvement in the reflex neurovascular dystrophy, despite various therapeutic regimens, until the patient's death from malignancy. At this time, the authors compiled a total of 63 case reports (4 of which were reported) and have proposed a classification to differentiate 4 types of disorders in combination according to whether there is a very probable, probable, or possible link or whether the combination is strictly a coincidence. The pathogenic mechanism remains a mystery, when a link is observed; but it never corresponds to criteria to describe a paraneoplastic disorder. Finally, the authors insist on the practical value of detecting this combination, even if due to chance: in order to systematically detect cancer in the presence of any reflex neurovascular dystrophy, and especially to be conscious of a possible reflex neurovascular dystrophy, besides possible metastatic lesions, in the presence of osteoarticular pain present in a patient with cancer. Such a diagnosis, although difficult to realize, has great prognostic and therapeutic interest.

Aged↗
PubMed1986

Effect of dexfenfluramine on body weight set-point: study in the rat with hoarding behaviour.

The food hoarding behaviour paradigm (HB) was used to evaluate the modification of the set-point of body weight (BW) regulation induced by dexfenfluramine (D-FF) in rats fed with chow or previously made obese by a cafeteria diet for 51 days. Daily injections of D-FF at a dose of 7 mg/kg (i.p.) induced a 58.5 g shift-down of the BW set-point in a group of chow fed rats submitted to HB measurement, and induced an equivalent weight reducing effect in a control-BW group always fed with chow ad libitum. In the rats fed ad libitum with the cafeteria diet, the BW reducing effect of D-FF(7 mg/kg/day) was about twice as great as in the lean rats. The HB measurement indicates that the vehicle-injected/cafeteria-obese rats had a BW set-point 54.6 g lower than the BW they reached when fed ad libitum with the cafeteria diet. It was concluded that the hyperphagia induced by the cafeteria diet was above that needed for BW regulation, and that D-FF may suppress this unregulated weight increase. In the cafeteria-obese rats submitted to HB measurement and D-FF injections a BW set-point 110.7 g lower than their initial ad libitum BW was observed. It is concluded that D-FF has induced a double effect in these rats: (1) a shift-down of the BW set-point and (2) the suppression of the unregulated weight increase induced by the cafeteria diet.

Animals↗
PubMed1986

Fibroblast-dependent tumorigenicity of cells in nude mice: implication for implantation of metastases.

The inadequate nature of the microenvironment is one of several factors considered in the failure of tumor engraftment in athymic mice; in the present work, we have tried to more adequately reconstitute it by injecting tumor cells together with fibroblasts. We have demonstrated that the s.c. co-inoculation of fibroblasts with different kinds of tumor cells of animal origin [rat rhabdomyosarcoma (RMS) 9-4/0, rat hepato-carcinoma FAO] or human origin (colonic adenocarcinoma HT29, Ewing's sarcoma pleural metastasis EW-S1) is necessary for tumor take and growth when the number of tumor cells alone is below the tumorigenic dose. We have shown that the s.c. coinoculation of 10(6) fibroblasts and 10(2) RMS 9-4/0 tumor cells induced a tumor take in all the recipient mice, while 10(2) tumor cells alone never gave any tumor. With a tumorigenic number of RMS 9-4/0 tumor cells (10(4), addition of 10(6) fibroblasts decreased the delay between cell injection and tumor appearance, thereby increasing tumor take and growth rate. These results were observed not only in nude animals (mice and rats) used as recipient animals but also in normal WAG rats receiving the syngeneic RMS 9-4/0 tumor cells, and they were independent of the nature or origin of the different fibroblasts cells. This helper effect has also been observed in the normal WAG rats. I.v. injection of tumor cells from a poorly metastatic 9-4/8 subline, derived from the RMS 9-4/0 line and mixed with 10(6) fibroblasts, gave a high number of lung colonies. Addition of 10(6) irradiated 9-4/8 tumor cells instead of fibroblasts did not increase the lung colonizing potential. Fibroblast-conditioned medium mixed with tumor cells instead of fibroblasts also enhanced tumor take and size but to a lesser extent than did the fibroblasts themselves. Only endothelial cells cultured from porcine aorta had a similar helper effect among the cells tested. It is argued in the discussion that the proliferating state of cultivated fibroblasts is a determinant factor conferring upon them the ability to promote tumor cell growth, while fibroblasts very numerous at the implantation site but quiescent might not be efficient in cooperation. Changes in fibroblast morphology and physiology may be necessary in order for tumor cells to express their tumorigenicity.

Animals↗
PubMed1985

Chronic administration of sulbutiamine improves long term memory formation in mice: possible cholinergic mediation.

Thiamine deficiency in both man and animals is known to produce memory dysfunction and cognitive disorders which have been related to an impairment of cholinergic activity. The present experiment was aimed at testing whether, inversely, chronic administration of large doses of sulbutiamine would have a facilitative effect on memory and would induce changes in central cholinergic activity. Accordingly mice received 300 mg/kg of sulbutiamine daily for 10 days. They were then submitted to an appetitive operant level press conditioning test. When compared to control subjects, sulbutiamine treated mice learned the task at the same rate in a single session but showed greatly improved performance when tested 24 hr after partial acquisition of the same task. Parallel neurochemical investigations showed that the treatment induced a slight (+ 10%) but significant increase in hippocampal sodium-dependent high affinity choline uptake. The present findings and previous results suggest that sulbutiamine improves memory formation and that this behavioral effect could be mediated by an increase in hippocampal cholinergic activity.

Animals↗
PubMedDate not supplied

[Clinical aspects of receptors; from animal models to physiopathological concepts. Experience with fenfluramine].

The fenfluramine racemate belongs to a new therapeutic class of molecules acting on food intake, without psychostimulant or addictive potential. This molecule was extensively studied in the treatment of obesity and its action was better understood by studying the dextrogyre and levogyre enantiomers. New methods allowed to show that dexfenfluramine (the dextrogyre isomer) worked through a serotoninergic activity which was responsible for the effect on food intake and disorders of eating behavior. New pharmacological concepts have emerged by using this molecule and new animal models, nearer to human pathology, were found (stress induced eating, carbohydrate selection...). Molecular Biology and Neurosciences have already led to a better knowledge of the central mechanism of action of the molecule by describing its effect on receptors and binding sites; however a lot of other concepts remain to be discovered.

Animals↗
PubMedDate not supplied

Nutritional intake and recreational physical activity in healthy elderly women living in the community.

PURPOSE: Recreational physical activity, which increases energy expenditure, may help to maintain proper food intake. To compare the nutritional intake of inactive, active and very active healthy elderly women. METHODS: Eighty-two women were recruited in the community. Participants had to be > or = 65 years and in good health (< or = 2 drugs, < or = 1 major illness, < or = 1 surgical operation, no disability in basic or instrumental activities of daily living and no cognitive impairment). We compared food intakes between the 26 inactive (age 73.9 +/- 7.7 y, BMI 24.3 +/- 3.2 kg/m2), the 29 active (age 71.5 +/- 5.6 y, BMI 23.2 +/- 3.5 kg/m2) and the 27 very active (age 70.9 +/- 4.8 y, BMI 24.3 +/- 3.2 kg/m2) healthy women. The nutritional intake was evaluated by a three-day food record. Macronutrient, mineral and vitamin content were derived from tables. Self-reported type, duration and frequency of recreational physical activities during the last month were converted into energy expenditures. RESULTS: Despite high levels of energy intake (mean 1743.9 kcal/d), mean intakes of calcium, vitamin B1, E and folic acid were lower than Recommended Dietary Allowances (-26.2%, -12%, -50.8%, -2.4% respectively) in the whole sample. There were no significant differences of energy intake and quantities of nutrients between the groups except for calcium intake which was significantly higher in inactive women (p=0.04). CONCLUSION: Active healthy elderly women do not have a better nutritional profile than their inactive peers.

Aged↗