Tissue reaction to subcutaneous implantation of a collagen sponge. A histological, ultrastructural, and immunological study.

The biocompatibility of a subcutaneously implanted bovine collagen sponge (Haemostagen) was studied in rats by analyzing tissue reactions up to 3 months by histological and ultrastructural methods; in addition, the level of serum antibodies to bovine type I collagen (the major implant collagen) was measured by solid-phase radioimmunoassay. By 8 h after implantation, the implant was completely filled with polymorphonuclear cells (PMNs). After 8 days, fibroblasts had developed a granulation tissue within the sponge and the PMNs had almost disappeared. The small residue that remained after 1 month consisted of some densely packed collagen fibrils containing giant cells, which had disappeared by 3 months. No antibodies to bovine type I collagen were found in the sera of implanted rats.

[Optical and scanning electron microscopic study of the structural development of the cecum and colon walls in the rabbit (Oryctolagus cuniculus L.) during the perinatal period]. / Etude en microscopie optique et electronique a balayage de l'evolution structurale des parois du caecum et du colon, durant la periode perinatale, chez le lapin (Oryctolagus cuniculus L.).

The study, through optical and scanning microscopy, of various developmental stages, from the 24th day of gestation to the 13th day after birth, shows a quick development of the structures of the caecal and colic mucosal layers to the adult forms, from the very first week of postnatal life. The distal part of the colon is full-grown before the other parts of the alimentary canal, and is particularly rich in mucous cells. The caecum is the place where an early lymphoid defense is provided, from the 30th day of gestation.

Evolution of glycogen and blood metabolites after controlled suckling at two periods of lactation in young rabbits.

In natural conditions young rabbit nurses once a day and therefore ingests the whole of his daily caloric intake during a single meal. The present work investigates glucose homeostasis during perinatal period in young rabbit by assessing blood glucose and glycogen stores before and after one single meal. Ponderal data, glycogen and blood metabolites were determined in 1-4 day- and 17-21 day-old rabbits before suckling and at different times (1, 3, 6, 9, 24, 48, 72 h) after controlled suckling. In "young" and "old" rabbits hepatic glycogen stores were exhausted after 48 and 72 h of fast. Within the first hours following milk ingestion, muscle and carcass glycogen did not vary until 9 h in the "young" and until 24 h in the "old" without notable variation of glycemia. From 24 to 72 h young rabbits were in a fasting period with low hepatic glycogen and a decrease of muscle and carcass glycogen, but glycaemia decreased only slightly at 48 and 72 h in "young" and at 72 h in "old" As blood alanine was decreased, it appears that gluconeogenesis was effective and that alanine-glucose and Cori cycles were operating in these conditions.

[In vitro study of the lipase activity of bacterial strains isolated from the rabbit cecum on C14-labeled triolein]. / Etude in vitro de l'activité lipasique de souches bactériennes isolées de caecum de lapins sur la trioléine marquée au 14C.

The lipase activity of bacterial species isolated from the caecum of conventional rabbits was studied by means of two groups of tests: (1) bacteriologic isolation and an identification of nine aerobic and anaerobic clones and (2) incubation of each of these clones in the appropriate medium in the presence of labelled triolein (oleyl 1-14C), a biochemical analysis of the radioactivity of the fractions obtained. The main results can be expressed in the following way: maximum hydrolysis of glycerides is achieved by two species: Bacillus licheniformis and Clostridium sporogenes. The reaction is proportional to the incubation time for incubations of less than 8 h. The release of fatty acids is concomitant to the synthesis of phospholipids and of fatty acid methyl esters.

[Tolerance and metabolic results of long-term administration of a mixture of saturated triglycerides by recto-colic route in rabbits]. / Tolérance et conséquences métaboliques résultant de l'administration chronique de mélange de triglycérides saturés par voie recto-colique chez le lapin.

Rabbit's and Dog's colonic absorption of triglycerides is shown in previous works. Further, we are studying the possibility to use the rectal route for nutritive substances. This way remains now poorly used and an exceptional therapeutic. However, bringing triglycerides in adequate state would be an energetic, supply, all the more as it is very difficult to provide potent caloric source in parenteral nutrition. This is why we investigate, on the Rabbit, the issues of chronic administration of glycerides by rectal route, on caloric balance and on a biochemical view to seek for in lipid composition of tissues the print of lipids administrated by transanal way. The animals are individually housed in metabolism units feeding a standard diet and drinking ad libitum. The treated subjects are given by transanal way, twice a day, for eight weeds, a sum of 1 g/kg of medium chain triglycerides. The metabolic balance-sheet is daily drawn. The clinic balance-sheet is set on the end, by biological controls to explore the hepatic and renal function (prothrombine ratio, transaminases (SGOT, SGPT), ornithine, carbamyl transferase (OCT), urea, total proteins ratio and electrolyte imbalance. We measure also the concentration of total lipids plasma and tissue (liver, kidney, heart, lungs, perirenal adipose tissue). The triglyceride composition and fatty acid composition of different lipids fractions of control and treated subjects are analyzed by gas-liquid chromatography. The animals support perfectly, without damage, a chronic and massive (1 g/kg/each day) administration of medium chain triglycerides by rectal route. The growth of treated subjects is normal. On the opposite, they adjust their alimentary consumption with the caloric charge of the diet, this is the reason why the reduction is about 12p. 100 with respect to the control animals. The coli-rectal administration of saturated glycerides produces at middle end only qualitative variations of lipids extracts. They essentially affect the triglyceride and fatty acid fraction of the tissue lipids, they become intermediate between that of control animals and the mixture administered by the transanal way. These results prove the integration of the glycerides in the metabolic pathway. They show the problem of the colonic absorption for the liposoluble substances. They authorize researches in view of a possible caloric assistance by this way.