Fetal intestinal transplant as an accessory enteral segment.

Fetal tissue transplantation has gathered considerable interest among researchers dealing with organ transplantation. A large number of studies concerning fetal intestinal transplantation have been published in the past 2 decades, almost all of them aiming to determine the feasibility of a properly functioning fetal transplant in continuity with the host's own enteral system. This study was designed to determine the absorptive capacity of the neogut in vivo, without anastomosing the transplant to the host's intestine, and to evaluate its use as an accessory enteral segment. Intestinal segments taken from Wistar albino fetuses were transplanted subcutaneously into the abdominal wall of 20 Sprague-Dawley rats. Immunosuppression was maintained by daily cyclosporin A (Cy A) 10 mg/kg injections s.c. and evaluated by determination of serum Cy A level and T-helper/T-suppressor cell ratio. The neogut was converted into a Thiry-Vella loop 2 weeks after transplantation. A test solution composed of 20% glucose and Trophamine was perfused via the stomas; glucose and amino acid absorption gradients were calculated. The gamma-glutamyl transferase (GGT) activity and mitotic index of the neogut were determined. Results were compared to those obtained from the host. There was no significant difference (P > 0.05) in glucose absorption between the neogut and the host tissue. Amino acid absorption and specific GGT activity were significantly less (P < 0.01) in the neogut. There was no significant difference (P > 0.05) between neogut and host intestine in mitotic index. Our data support the idea of using a transplanted fetal intestinal segment as an accessory feeding route.

Liver delta-aminolevulinate dehydratase activity in amitriptyline- or chlorpromazine-treated rats.

Amitriptyline (AMT) and chlorpromazine (CPZ) (0.5 mg per animal, i.p.) were injected into rats separately for 30 days and their effects on heme metabolism in liver were examined. Significant decreases in the delta-aminolevulinate dehydratase activity were observed following the administration of both drugs (mean value of AMT-group: 6.58 U/g tissue; and CPZ-group: 7.04 U/g tissue) in comparison to that of controls (11.71 U/g tissue); however total liver heme content was not altered. When 24-h urinary excretions of delta-aminolevulinate (ALA) and porphobilinogen (PBG) were measured on the last day of the experiment, a slight (AMT-group: 38.40 micrograms/day) to distinct (CPZ-group: 59.11 micrograms/day) increase of urinary ALA was observed, while PBG excretion tended to decline only moderately under CPZ (3.52 micrograms/day), but significantly in presence of AMT (2.16 micrograms/day). Mean values obtained from control group were 32.12 micrograms/day for ALA and 4.25 micrograms/day for PBG.

Gamma-glutamyl transpeptidase and acetylcholinesterase activities in brain capillaries of cholesterol-fed rabbits.

Cerebral microvascular endothelium, the constituent cell of the blood-brain barrier, is enriched in the enzyme gamma-glutamyl transpeptidase (GGT). This enzyme plays a role in the regulation of amino acid uptake and transport, and in the gamma-glutamylation of serotonin, dopamine and norepinephrine. Recent studies have demonstrated that GGT activity is modulated by cholinergic-adrenergic agonists. The levels of the acetylcholine-catabolizing enzyme acetylcholinesterase (AChE), may therefore be related to the modulation of the GGT activity. In this study, the activities of GGT and AChE in microvessel-enriched fractions were assayed after feeding of rabbits a high cholesterol diet. A 21% decrease of GGT activity and a 44% increase of AChE activity appeared at the end of dietary treatment.

Modulation of gamma-glutamyl transpeptidase activity by dietary eicosapentaenoic acid and vitamin E in livers of rabbits on hypercholesterolemic diet.

Rabbits were fed high-cholesterol diets containing either eicosapentaenoic acid (EPA) or vitamin E at doses of 80 mg and 100 IU per day, respectively. Liver gamma-glutamyl transpeptidase (GGT) activity and liver cholesterol and phospholipid levels were determined following the administration of the diets for 45 days. The feeding of cholesterol produced the highest concentrations of cholesterol in livers accompanied with the elevated enzymatic activity. Addition of EPA to the diet dramatically reduced GGT activity to normal levels, whereas vitamin E administration caused only a slight reduction.

Influence of eicosapentaenoic acid and vitamin E on hepatic hydroxyproline content in rabbits fed cholesterol-rich diet.

The effect of eicosapentaenoic acid (EPA) and vitamin E on hepatic hydroxyproline content, as an index of collagen was examined in rabbits receiving cholesterol rich diets for a period of 45 days. Rabbits were divided as control (A) and cholesterol fed groups (B, C, D). Group C received 80 mg. of EPA and group D received 100 IU of vitamin E daily in addition to the cholesterol rich diet (2% w/w) which was solely given to group B. The maintenance of rabbits on high cholesterol diets resulted in significantly increased liver cholesterol concentrations. This effect was most pronounced in rabbits receiving cholesterol alone. Hepatic triglyceride levels remained unchanged in all cholesterol-fed rabbits, but total phospholipid levels in liver significantly decreased in EPA and vitamin E supplemented rabbits. An interesting finding was the increase in hepatic hydroxyproline content in rabbits following the administration of EPA and vitamin E to cholesterol rich diet.

Influence of eicosapentaenoic acid and vitamin E on brain cortex Ca2+ ATPase activity in cholesterol-fed rabbits.

The influence of eicosapentaenoic acid (EPA) and vitamin E on brain cortex Ca2+ ATPase activity was examined in rabbits receiving cholesterol-rich diets for a period of 45 days. Rabbits were divided as control (A) and cholesterol-fed groups (B, C, and D). Group C received 80 mg of EPA and group D received 100 IU of vitamin E every day in addition to the cholesterol-rich (2%, w/w) diet which was solely given to Group B. Rabbits receiving cholesterol alone had a significant reduction in brain microsomal phospholipid level. Microsomal free cholesterol and polyunsaturated fatty acids (PUFA) were significantly increased in all experimental groups. Cortex microsomal Ca2+ ATPase activity was found to be inhibited in all cholesterol-fed rabbits as compared to controls, but the highest inhibition was seen in rabbits fed cholesterol alone. Additions of EPA or Vitamin E to the cholesterol-rich diets resulted in a recovery of the enzymatic activity. It is concluded that cholesterol feeding without any addition of PUFA or antioxidant agent might cause an inhibition of brain Ca2+ ATPase activity in rabbits, thereby leading to the dysfunction in ion transport and neurotransmitter release.

Activity of gamma-glutamyl transpeptidase in human fetal membranes.

The presence of gamma-glutamyl transpeptidase in human fetal membranes and alterations in enzyme activity during the gestational period were studied. Fetal membranes from term deliveries exhibited a high enzymatic activity, whereas membranes from preterm deliveries showed alterations with regard to the gestational weeks. These alterations were found to be similar to those which had previously been obtained from rat placentae during fetal growth and development.