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Biomedical subjects

J Belleville

Publications and source records attributed to J Belleville.

At least 73 records · Page 4Linked to original sources
PubMed1987

Time course of changes in rat serum apolipoproteins during the consumption of different low protein diets followed by a balanced diet.

The effects of protein malnutrition (PM) followed by refeeding a balanced diet on apolipoprotein and lipid contents of the serum lipoproteins were studied in young Wistar male rats. The changes of serum apolipoproteins were compared with the appearance of fatty liver during PM and its disappearance during refeeding. The control group (T) was fed a balanced diet containing 15% casein for 42 d. Two depleted groups (C) and (G1) were fed for 28 d low protein diets containing 2% casein and 5% gluten, respectively, and then were fed the balanced diet for 14 d. During PM a concentration of triacylglycerols (TGs) in liver in the two depleted groups increased; the level in rats fed 2% casein was twice that in rats fed 5% gluten. There was a significant negative correlation between serum TGs and liver TGs. The serum apolipoproteins (apo) did not respond consistently. The high-density lipoproteins apo A-I, A-II and A-IV, which are more than 50% synthetized in the intestine, remained essentially unchanged, thus showing resistance to protein malnutrition. The very low density lipoproteins apo B and total apo C, which mainly originate from liver, were significantly lower in malnourished groups than in controls, while the liver TGs accumulated in malnourished groups. Only the levels of total apo C and apo B48 were correlated with hepatic TG steatosis during malnutrition and refeeding.

Animals↗
PubMed1987

[Influence of protein malnutrition followed by a balanced refeeding on the synthesis level of pancreatic hydrolases in growing rats].

The intake of 5% gluten + casein (4:1, W:W) (PM) (E group) diet compared to 20% (16:4, W:W) (control group) caused an overall decreased synthesis. With the duration of PM, Tg2 and Chtg1 synthesis remained steady, while lipase synthesis decreased and amylase synthesis increased. At the beginning of refeeding (two days), in E group Tg2 and amylase synthesis was increased with rebound effect compared to controls, then decreased, Chtg1 synthesis was higher than control synthesis and remained constant, lipase synthesis was increased and reached the control value only after 9 days.

Animals↗
PubMed1986

Rat coagulation factor V purification and production of the monospecific antiserum.

An original method was applied to purify rat factor V. The final preparation had a sp. act. of 45 U/ml for a 2500-fold purification with a yield of 43%. The final product is partially activated since it is 4.7-fold activable by RVV-VAE vs 6.3 in plasma. It can explain the presence of some of the four slightly stained additional bands found in SDS-electrophoresis. Finally, results of the purification suggest that rat factor V is a 338,000 single chain glycoprotein with a strong molecular asymmetry. A factor V deficient fraction was produced and used to adsorb an anti-factor V antiserum. This adsorbed antiserum was found monospecific against purified rat factor V.

Animals↗
PubMed1986

[Chronologic studies of the effects of a hypoproteinic diet followed by an equilibrated diet on delta-6 and delta-5 desaturations of linoleic acid in liver microsomes in the rat].

A low protein diet affects amounts of linoleic and arachidonic acids in hepatic microsomal phospholipids of growing rats. Are the changes related to modifications in microsomal delta 6- and delta 5- linoleic acid desaturase activities? Two groups of Wistar rats weighing 80 +/- 5 g at the beginning of the experiment were used: Control group (T) was fed on a 16% gluten + 4% casein diet for 53 days; Experimental group (E) was fed on a 4% gluten + 1% casein diet for 26 days (MP) then Control diet for 27 days (RE). After 2, 14 and 26 days of MP and 2, 15 and 27 days of RE, rats of each group were sacrificed. Protein and water contents of liver, quantitative fatty acid, composition of total lipids in liver and hepatic microsomes were determined. delta 6- and delta 5- linoleic acid desaturase activities were estimated from incubation of liver microsomes with [1-14C] C 18: 2 n-6 or [2(14)C] C 20: 3 n-6 respectively. The low protein diet stops practically ponderal growth. The fatty-acid compositions of microsomal total lipids of E rats were affected in comparison with values of T rats. These modifications persist after 27 days of RE. The C 20: 4 n-6/C 18: 2 n-6 ratio in microsomal total lipids was slightly different between T and E rats but increased strongly during refeeding. Same modifications take place in the fatty-acid composition of hepatic total lipids. After two days of MP, delta 6- and delta 5- desaturase activities were depressed, phenomenon that not persist in the course of MP. These enzyme activities increase to higher values than those of the T after two days of RE.

Animals↗
PubMed1985

Immunolocalization of factor V in adult and fetal rat liver.

Immunolocalization of the factor V was performed in adult and fetal rat liver by means of an indirect peroxidase labelling. This could be done owing to the production in our laboratory of a mono-specific antiserum anti rat factor V. In all the cases (perfused and non-perfused adult liver and fetal one) the observation of the sections has revealed an intense circular or granular labelling into all the hepatocytes whatever was their localization in the hepatic lobule. Hepatic endothelial cells seemed to be negative for factor V and this aspect of our results was discussed.

Animals↗
PubMed1985

In vitro study of the inhibition of coagulation induced by different radiocontrast molecules.

The anticoagulant activity of seven intravascular radiocontrast molecules (RCM) was evaluated in different in vitro systems using citrated human plasma. Each RCM was tested in a concentration range of 5 to 50 mM. The thrombin time and the reptilase time showed a dose-dependent lengthening of fibrinoformation, the recording of fibrinoformation exhibited a significant delay of fibrin monomer generation and polymerization although the amplitude of the fibrinoformation was not decreased. The interfering effect with fibrin clot formation impairs also global coagulation tests and monospecific coagulation tests using fibrinoformation as the final step of the assay, but a possible interaction between RCM and some specific coagulation factors cannot be excluded. RCM potentiated the anti-thrombin action of heparin but the inhibition or delay of fibrinoformation is not related to an antithrombinic effect of contrast media. The thrombin amidolytic activity is not modified by RCM but the generation of FpA is delayed and decreased. The ultrastructure of the fibrin clot is not altered at the end of the polymerization.

Adult↗
PubMed1985

Experimental DMNA induced hepatic necrosis: early course of haemostatic disorders in the rat.

The course of haemostasis defects was investigated in dimethylnitrosamine (DMNA) acute liver necrosis. Before 18 hr there was no evidence of disseminated intravascular coagulation (DIC) nor of abnormal fibrinolysis. At 12 hr the level of the vitamin-K-dependent factors (factors II, VII, IX and X) was reduced to 25-63% of control. Factors V and VIII:C levels decreased to about 10 and 20% by 12 hr. Factor V was the only molecule which decreased significantly by 6 hr. The rapid decrease of these proteins might be related to an early parenchymal functional impairment attested by early structural lesions observed in the endoplasmic reticulum and nucleus. The isolated decrease of factor V in the absence of any significant change in serum transaminase (SGOT and SGPT) levels is proposed, at least in the rat, as an early criterion of hepatic failure.

Alanine Transaminase↗
PubMed1985

An ultrastructural study of the contact between type I collagen assemblies and the induced human platelet aggregates.

Several type I collagen assemblies have been tested for their ability to induce platelet aggregation: a molecular solution, native and reconstituted native-type fibrils, segment long spacing aggregates (SLS) and an unordered collagen multimer. The ultrastructure of the inducer has been observed before its introduction into the platelet suspension as well as within the final aggregates. The following results have been obtained: 1) platelet aggregation was induced by the monomeric solution of collagen only after a long lag phase. While the original solution did not contain fibrillar elements, the platelet aggregates were in contact with collagen filaments showing a faint banding pattern. The results confirm that the longer lag time recorded is necessary for the collagen to polymerize and that the monomeric collagen actually does not induce platelet aggregation; 2) native and reconstituted native-type fibrils, SLS and unordered collagen multimer similarly induce platelet aggregation and were not modified during the course of this phenomenon; 3) although the general ultrastructure of the contacts between platelet and collagen assemblies were similar, a difference was noted in the extent of contact: a focal zone with native-type fibrils, numerous zones of contact with SLS and very extensive contact with unordered multimer. These results suggest that the combination of three factors are necessary to trigger platelet activation by collagen: the nature of the active sites on collagen, the density of these sites and the geometry of the collagen assembly.

Animals↗
PubMed1984

Drugs effect on platelet survival time: comparison of two pyrimido-pyrimidine derivatives in patients with aortic or mitral replacement.

A prospective randomized trial of the effects of 2 antiplatelet aggregating drugs, dipyridamole (375 mg/d), a related substance RA 233 (1500 mg/d) and placebo, concomitantly with oral anticoagulants, was carried out in patients with prior valvular replacement. The study was aimed to determine effect on platelet survival time (PST) of these 2 agents. The trial sample consisted of 40 males and 15 females aged 40-70 years (average 53 years). 32 received Björk-Shiley valve in aortic position, 23 underwent mitral valve replacement: 3 with Cooley-Cutter, 11 with Lillehei-Kaster 500 and 9 with Starr-Edwards 6120 prostheses; 28 patients had aortic stenosis, 21 aortic insufficiency. All the PST measured after 3 months of treatment were within normal ranges and not different between placebo, dipyridamole or RA 233 treated subjects: averages in days were, respectively, 7.49, 7.11 and 6.88. The present study did not support the claim that modern valve prosthesis could lead to a shortened PST.

Adult↗
PubMed1984

A freeze-fracture and thin section study of the interaction of blood platelets with native type I collagen fibrils.

The membranes of non-activated and activated human blood platelets have been studied with freeze-fracture and conventional electron microscopy. Aggregated platelets activated by ADP or by native collagen fibrils did not show any intramembrane particle clustering. No intramembrane modification is detectable at the contact regions with collagen fibrils. However, a local densification of the cortical cytoplasm is noted in thin sections where platelets make contact with collagen fibrils. These results suggest that either the membrane receptor for collagen is not visualized by freeze-fracturing or that, as suggested previously, the binding site on collagen may not have a specificity and affinity as high as expected from a conventional receptor-ligand interaction.

Blood Platelets↗
PubMed1983

[Comparative study of the effects of 2 types of protein-energy malnutrition followed by a balanced refeeding, on the lipase, phospholipase A2 and amylase activities of the pancreas and pancreatic juice in the growing rat].

The intake of 2 p. 100 casein diet as only protein source decreased overall phospholipase A2 activity. Amylase activity was more affected than lipase one. The effects of intake of 5 p. 100 gluten diet as only protein source were less important than 2 p. 100 casein diet. Refeeding on 20 p. 100 or 15 p. 100 casein diet caused a considerable increase of phospholipase A2, lipase and amylase activities.

Amylases↗
PubMed1983

[Course of the levels of myofibrillar proteins in the cardiac ventricles of adult rats in protein malnutrition followed by a balanced diet].

Adult male Wistar rats weighing 320 +/- 20 g at the beginning of the experiment were divided into two equal lots. A reference lot (T) was fed on a balanced diet containing 23,5 p. 100 mixed protein, for 60 days. A deficient lot (E) was fed on a low protein diet (3 p. 100 cereal protein) for 30 days (malnutrition), then on a balanced diet for 30 days (refeeding). When the food intake was expressed in 100 g of body weight/day, both lots ate about the same amount throughout the experiment. On the contrary, the amount of N ingested/100 mg of body weight/day by the E rats was only 11 p. 100 of that of the T lot. After 30 days of refeeding, the mean weight of the E rats equalled 90 p. 100 of that of the T rats. In the E lot, during malnutrition, the nitrogen balances were always positive and their nitrogen CDU were ranged between 73-83 p. 100 in comparison with 86-88 p. 100 in the T lot. The protein concentration of cardiac ventricles was the similar in both lots of rats, during malnutrition and refeeding periods. On the contrary, the myofibrillar protein concentration was increased in the E rats during these two phases. After separation of subunits sizes of muscle proteins by sodium dodecyl sulphate gel electrophoresis, we observed that the concentrations of myosin, actin, troponin-tropomyosin complex, myosin light chains, evolved in the same way that the total myofibrillar proteins. A relative degree of cardiac myocontractile protein sparing is suggested in our chronic protein malnutrition of adult rats.

Animals↗
PubMed1982

Contrast agents used for excretory urography impair platelet function in human patients.

The platelet function was investigated in 65 patients submitted to diagnostic excretion urography (injection of 60 ml contrast medium). Blood sampling was performed before (T0) 90 seconds after (T1) and 30 minutes after (T2) injection of the radiocontrast molecule (RCM). Five RCM of different osmolality ionicity and nature of the lateral chain have been tested. Platelet aggregation, platelet release of ATP, osmolality, total calcemia and ionized calcium level were determined on each plasma sample as well as RCM concentration at T1 and T2. Decrease (20 - 40%) of platelet aggregation occurred at T1, whichever platelet aggregating agent (ADP, collagen, Ristocetin or thrombin) were used (significant after Iopamidol 300 and Na Meg Ioxaglate). Platelet release of ATP induced by collagen was also decreased or delayed. These changes were rapidly reversible and a tendency to improvement was observed at T2. Among the five RCM tested, one (Na Diatrizoate) might be a proaggregating agent. No changes of osmolality occurred in the plasma and no correlation could be established between RCM concentration and platelet inhibition. A pathogenic hypothesis is suggested by the significant fall of total and ionized calcium level after RCM injection.

Adenosine Triphosphate↗
PubMed1982

[Comparative study of the effects of 2 types of protein-energy malnutrition followed by a balanced realimentation on trypsin and chymotrypsin activity of the pancreas and the pancreatic juice of the rat].

The intake of 2 p. 100 casein or 5 p. 100 gluten diet as only protein source caused overall protein synthesis and immediately stopped the rat growth. Trypsin activity was less affected than chymotrypsin activity in pancreas. Refeeding on 20 p. 100 or 15 p. 100 casein diet caused a considerable increase of trypsin and chymotrypsin activities during the first week.

Animals↗