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Biomedical subjects

G Lacombe

Publications and source records attributed to G Lacombe.

22 records · Page 2Linked to original sources

Experimental systolic and diastolic overloading in rats: total proteins turnover rate. Enzymatic and structural properties of myosin.

The fractional turnover rate of the total cardiac proteins has been measured by using the continuous infusion technique with 3H lysine. It augments by a factor of 3 in systolic as well as in diastolic overloading, but in the former the peak was reached within the first week after operation and in the later the peak was not reached until the 14th day. The myosin structure and enzymatic properties have been studied in several huge hypertrophic hearts (around 100% hypertrophy). In this condition the burst size of myosin is normal, as well as its K+ ATPase, but there is a sharp decline in the Ca2+ ATPase activity. Moreover, antibodies against native or defolded heavy meromyosin exhibit, a vertical shift in microcomplement fixation when made to react with molecules extracted from hypertrophied hearts. The normal isozymic pattern of rat heart myosin, as shown in non dissociating electrophoresis, was reversed.

Adenosine Triphosphatases↗

Imbalance between jejunum and ileum in the response of brush border hydrolases to oral feeding after intravenous alimentation in rats.

The effect of oral refeeding after total parenteral nutrition (TPN) on brush border hydrolases was measured in the proximal jejunum and ileum of adult rats. The animals received intravenously for 4 days a mixture of Intralipid 10% and Vamine-Glucose. At the end of TPN, oral feeding was reinstituted and the rats were fed with an isocaloric standard diet (60% carbohydrate, 17% protein, 3% lipid). Sucrase, isomaltase, lactase, and aminopeptidase N activities were measured at the end of TPN and at 1, 3, and 5 days after TPN. Sham-operated rats nourished orally with the standard diet were used as controls. In both intestinal segments, lactase activity showed no significant changes at the end of TPN or during oral realimentation. Isomaltase, and especially sucrase activities, exhibited an important drop at the end of TPN. After TPN, a complete restoration of isomaltase and sucrase activities was obtained in the jejunum only. During oral refeeding a 40% deficit in sucrase activity persisted in the ileum throughout the experimental period, whereas normal isomaltase activity was restored in this segment. Aminopeptidase N activity was lowered by TPN and recovered normal values within a few hours after oral realimentation. Thus, reinstitution of oral feeding after TPN should take into account that the intestine is capable of digesting normal amounts of dietary protein but has a reduced tolerance for carbohydrates.

Animals↗