Free radicals in myocardial injury: experimental and clinical studies

The exposure of cardiac cells to OFR generated artificially, showed a marked decrease (p less than 0.01) in cellular utilization of glucose along with a significant decrease in calcium uptake (p less than 0.05). We have also provided evidence for a direct relationship of neutrophil OFR production with the extent of myocardial ischemia in patients of myocardial infarction. Our data provides evidence for implication of OFR in myocardial injury and the pivotal role played by modulators like calcium, ECGF and prostaglandins in potentiating damage to the myocardium.

Calcium transport and Ca(++)-ATPase activity in spermatozoal plasma membrane vesicles of nifedipine-administered guinea pigs

Spermatozoal plasma membrane vesicles isolated from distal portion of the epididymis and vas deferens were found to contain Ca(++)-activated ATPase and calcium transport activities. Nifedipine was administered at two different doses (1.0 and 2.5 mg/kg b.w./day) and the effect was observed for both short- (4 week) and long-term (12 week) period. The cellular ionic calcium content and Ca(++)-ATPase activity were observed to be enhanced in the drug-treated animals. The recovery studies carried out after 4 and 6 weeks of withdrawal of the drug treatment exhibited partial to complete restoration of observed changes. The stimulatory rather than inhibitory effect of Nifedipine, a specific calcium channel blocker, on calcium uptake may suggest that voltage-sensitive calcium channels may be lacking in guinea pig spermatozoa. The stimulatory effect of the drug is speculated to be either by inhibition of Na(+)-Ca++ antiporter or G-protein activated agonistic effect or probably due to altered physicochemical properties of the drug-treated sperm plasma membranes.

Effect of indomethacin on serum lipids, lipoproteins, prostaglandins and the extent and severity of atherosclerosis in rhesus monkeys

The present study evaluated indomethacin therapy--a nonsteroidal anti-inflammatory drug--on experimental hyperlipidemia and atherosclerosis in Rhesus monkeys. Twenty-four monkeys were divided randomly into four groups of six. Two groups received stock pellet diet and two were given an atherogenic diet for six months. After this period, one stock diet-fed group and one atherogenic diet-fed group were treated with oral indomethacin (2.5 mg) on alternate days for a further six months. Serum lipids and lipoproteins were markedly elevated in atherogenic diet-fed monkeys. Generally, indomethacin did not exert a hypocholesterolemic effect; however, liver cholesterol was decreased (P less than 0.05) in atherogenic diet-fed monkeys treated with indomethacin. High density lipoprotein cholesterol was increased in stock diet-fed, indomethacin-treated monkeys but not in atherogenic diet-fed, indomethacin-treated monkeys. Apoprotein A-I was not affected by indomethacin in either stock or atherogenic diet-fed monkeys; however, the drug produced a significant (P less than 0.01) reduction of serum thromboxane B2 in stock diet-fed monkeys, without restoring the 6-keto-prostaglandin F1 alpha to pretreatment levels. A protective role of the drug was noted on both the extent and severity of aortic and coronary atherosclerosis.

Role of circulating immune complexes and platelet aggregation in the development of experimentally induced atherosclerosis in monkeys with normal intact vas deferens and following vasectomy

The study was undertaken in normal and vasectomized monkeys to elucidate the relationship of circulating immune complexes and platelet aggregability with experimental aortic and coronary atherosclerosis. Four groups of animals, viz. sham-vasectomized stock diet fed, vasectomized stock diet fed, sham-vasectomized atherogenic diet fed, were studied for a period of 1 year. An increased incidence of atherosclerosis was noted with high levels of circulating immune complexes in vasectomized monkeys. Platelets obtained from atherogenic diet fed monkeys had a clear tendency of increased aggregation and agglutination in the presence of ADP, epinephrine and ristocetin respectively. Vasectomy produced a significant enhancement in platelet aggregation response with ADP and epinephrine in atherogenic diet fed animals. The aortic and coronary atherosclerosis was also significantly increased in atherogenic diet fed groups both with and without vasectomy.

Distribution of apolipoproteins in normal individuals of various age groups

The study comprised normal controls with 10 males and 10 females in each decade of age starting from birth till greater than 70 years of age and also 20 cord blood samples (10 males and 10 females). In normal controls there was a progressive increase in the levels of total cholesterol and triglycerides in both men and women with age. Women had significantly lower levels of Tc and TG as compared to men until 40 years of age. Beyond this age levels of Tc were similar to those in men. HDL-c was lower in girls below 10 years of age compared to boys. Above 10 years of age women had significantly higher levels of HDL-c. Apo A-I and A-II levels were also significantly higher in women compared to men.

Verapamil stimulates Ca(++)-uptake and Ca(++)-ATPase in plasma membrane vesicles of guinea pig spermatozoa

Verapamil, a potent calcium channel blocker, was administered orally at three different doses to guinea pigs for both short- (4 weeks) and long-term (12 weeks) effects. The drug treatment stimulated Ca(++)-transport and Ca(++)-activated ATPase in isolated plasma membrane vesicles of guinea pig spermatozoa. Ca(++)-uptake studies exhibited partial to complete restoration of stimulated Ca(++)-transport during recovery period, whereas the CA(++)-activated ATPase system remained stimulated even after 4 and 6 weeks of withdrawal of the drug treatment. The lack of inhibitory effect of verapamil on Ca(++)-uptake ruled out the involvement of calcium channels in spermatozoal calcium uptake in guinea pigs. The stimulatory effect of the drug on CA(++)-uptake, on the other hand, might indicate the possible capability of this lipophilic compound to induce favourable changes in the lipid microenvironment of the membrane, wherein the integral membrane proteins operate.

Effect of verapamil on different spermatozoal functions in guinea pigs--a preliminary study

Verapamil, a calcium channel blocker, was administered orally using three different doses to guinea pigs. Both short-term (4 weeks) and long-term (12 weeks) effects of the drug were observed. The drug administration resulted in a marked decrease in sperm density, sperm motility and cellular energy content (ATP). Zona pellucida penetration by the sperm obtained from drug-treated animals was significantly lower when compared with sperm from normal animals. Histopathological findings exhibited partial arrest of spermatogenesis. Partial to complete recovery was observed after 4 and 6 weeks of withdrawal of the drug treatment.

Catecholamine-induced experimental cardiomyopathy--a histopathological, histochemical and ultrastructural study

An experimental model of myocardiopathy was induced in rhesus monkeys following noradrenaline (NA) infusion (20 ug/kg body wt/minute), for a period of 2 hours daily for three consecutive days. The animals were sacrificed after two hours (acute phase), forty-eight hours (sub-acute phase) and twenty-one days (chronic phase). Focal depletion of succinic dehydrogenase, increase in adenosine triphosphatase, acid phosphatase and appearance of large fat droplets in myocardial muscle was noted in the acute phase. Histopathological examination revealed focal edema, opacity and fuchsinorrhagia of the muscle fibres distributed in both the ventricles. Myofibrillar degeneration, myocytolysis and vacuolization with aggregation of lymphomononuclear cells were the significant features in the acute phase. During sub-acute and chronic phases, these features became less prominent and reparative changes with proliferation of fibroblasts became more marked. By the twenty-first day, irregular, focal scars replaced the necrosed myocardium. Ultrastructurally, heart muscle showed myofibrillar disorganisation, distortion of Z and A bands, dilatation of sarcoplasmic reticulum and swelling and rupture of mitochondria. Altered membrane permeability was evidenced by the presence of reaction products of horseradish peroxidase within the cardiac cells. In the reparative phase, however, myocytolytic changes regressed and collagen deposition was the prominent feature. This experimental study has several histological features simulating human cases of myocardial infarction without coronary occlusion.

Enzyme immunoassay (ELISA) for the detection of anticarbohydrate antibodies in rheumatic fever and rheumatic heart disease

Antibodies to group A streptococcal polysaccharide were estimated in the following groups of patients: (I) Patients with uncomplicated streptococcal pharyngitis: 10 patients, followed up for 3 months. (II) Patients with acute rheumatic fever: 8 patients with first attack followed up for one year. (III) Patients with reactivated rheumatic heart disease: 10 patients, followed up for one year. (IV) Patients with chronic rheumatic heart disease: followed up for one year. (V) normal controls without any history of sore throat/fever/vaccination/rheumatic disease: 10 patients followed up for one year. Group (I) patients did not show any significant elevation in anticarbohydrate antibodies by both ELISA and RIA. In the case of (III) and (IV), antibody levels were significantly higher as compared to group (V) and remained so till one year of follow up. In group (II) patients there was no significant rise in antibody levels. There was a good correlation between the ELISA and RIA used to detect the antibody levels. These findings suggest that the use of ELISA to detect anticarbohydrate antibody can be of help in diagnosing cases of rheumatic heart disease (both acute and chronic RHD).

Effect of vasectomy on serum lipids, platelet aggregability and development of ischaemic heart disease in rhesus monkeys

In this study the long term effects of vasectomy on serum lipid profile, in vitro platelet aggregability and the risk of developing acute myocardial infarction have been elucidated in a monkey model. Four groups were made viz. (I) atherogenic diet fed vasectomised, (II) atherogenic diet fed control, (III) stock diet fed vasectomised and (IV) stock diet fed control. The respective diets were fed for first 6 months and then half of the atherogenic and stock diet fed monkeys were bilaterally vasectomised. The remaining monkeys were sham-vasectomised. At the end of one year, norepinephrine infusion was given to all the monkeys each day for 2 hrs, for 3 consecutive days and animals sacrificed after 96 hrs. Although serum lipids were not altered following vasectomy, platelet aggregation response was significantly enhanced in atherogenic diet fed animals. ECG changes were suggestive of acute myocardial ischaemia in 4 monkeys, 2 each from gp. I and II. Histopathology of heart revealed patchy myocardial necrosis and haemorrhage only in one monkey of gp. I, while others had fuchsinorrhagia indicating ischaemic change. These findings are in contrast to those seen in vasectomised human subjects.

Physiological and histopathological changes in the intestines of mice challenged with S. typhi

Transport of Na+, Cl-, Ca2+ and 3-0-methyl-D-glucose (a non-metabolizable analogue of D-glucose) was worked out in control, infected and immunized-infected animals along with histopathological studies of the intestines in these groups. There was significant decrease (p less than 0.01) in net absorption of Na+ and Cl- in the infected group as compared to that in the control group. There was also a significant decrease (p less than 0.01) in 3-0-methyl-D-glucose uptake in the infected group. However, no change was found in the immunized group in any of the electrolytes and non-metabolizable analogue of D-glucose. These findings correlated well with the histopathological studies as the infected intestines showed complete disorganization of mucosal tissues with loss of epithelial cells from the villi whereas the mucosal lining and epithelial cells from the intestines of immunized mice were normal looking.

Towards the mechanism of protection against indomethacin induced gastro-intestinal ulceration by naloxone

Activities of lysosomal hydrolases have been evaluated in relation to indomethacin and naloxone, using purified lysosomal fractions from rat intestinal mucosa. Indomethacin treatment significantly decreased (p less than 0.001) lysosomal enzyme activities in purified lysosomes, while an increase in the activities was observed in intestinal homogenates. However, indomethacin could not affect lysosomal system in animals pretreated with naloxone, thereby establishing that naloxone neutralises the effect of indomethacin.

Effect of vasectomy on humoral and cell-mediated immunity in monkeys with experimentally induced atherosclerosis

The development of humoral and cell-mediated immune responses and circulating immune complexes following vasectomy were studied in rhesus monkeys fed a high cholesterol (atherogenic) diet. Four groups of monkeys were studied: (i) sham-vasectomized males fed a normal stock diet, (ii) sham-vasectomized males fed an atherogenic diet, (iii) vasectomized males fed a normal stock diet, and (iv) vasectomized males fed an atherogenic diet. Monkeys were observed for a period of 1.5 years. Sperm agglutinins and immobilizins in serum were detected in 100 and 60%, respectively, of vasectomized monkeys fed stock diet. In contrast, 60% of vasectomized monkeys fed an atherogenic diet showed agglutinins in their sera and only 20% exhibited immobilizins. The sensitization of lymphocytes by seminal plasma antigens was of a lower order in vasectomized monkeys fed an atherogenic diet as compared to those maintained on a stock diet. Circulating immune complexes (CIC) were present in both the groups of vasectomized monkeys but the level was higher in animals fed an atherogenic diet. The aortic atherosclerosis score was increased significantly in vasectomized monkeys fed an atherogenic diet, whereas the coronary atherosclerosis score was increased both in vasectomized males and in animals fed an atherogenic diet.

Renal involvement in Mycobacterium leprae infected mice. Histopathological, bacteriological and immunofluorescence study

Swiss albino mice were inoculated in the footpads with Mycobacterium leprae obtained from untreated lepromatous patient. The kidneys obtained from the animals sacrificed during different periods were processed for histopathology, presence of AFB and immunofluorescence studies. Renal lesions, AFB and immune complex deposits were seen in the infected animals. Such findings have not been studied in great detail in experimental leprosy earlier.

Venous involvement in leprosy: a venographic and histopathological correlation

Venous system involvement was studied by venography and vein histology in 30 leprosy patients irrespective of age, sex, duration of the disease, and treatment. Vascular abnormalities by venography were seen in 96.3% and by histopathological studies in 76.6% of patients. The percentage and severity of radiological and histological changes increased from tuberculoid to lepromatous in the disease spectrum. Perfect correlation of histology and venography was found in 40% of the paucibacillary patients and good correlation was found in 100%. In multibacillary patients perfect correlation was found in 29.4%, good correlation in 41.1%, and no correlation in 29.4% of the patients.

Isolation of monkey aortic lysosomes using Percoll density gradient

A novel technique involving the Percoll density gradient and 0.01M phosphate buffer has been employed for the first time on aortic tissue for isolation of lysosomes. The purity of the lysosomes has been established by marker-enzymes, acid phosphatase and N-acetyl-beta-D-glucosaminidase and latent activities of lysosomal hydrolases. The heavier fraction (density 1.08) obtained after Percoll density gradient centrifugation showed high specific activities of lysosomal hydrolases and these enzymes were markedly latent. Moreover this heavier (lysosome rich) fraction has been noted to be free of other sub-cellular contaminants.

Long term effects of vasectomy on experimental atherosclerosis in rhesus monkeys

Five groups of male rhesus monkeys, Gp. I--sham-vasectomized stock diet-fed (SVS), Gp. II--vasectomized stock diet-fed (VS), Gp. III--sham-vasectomized atherogenic diet-fed (SVA), Gp. IV--vasectomized atherogenic diet-fed (VA) and Gp. V--atherogenic diet-fed vasectomized monkeys (AV) were observed for a period of 1 1/2 years. Vasectomy per se had no effect on the level of serum or tissue lipids either alone or in combination with atherogenic diet feeding. Following vasectomy the involvement of aorta by fatty lesions was significantly increased and this occurred in animals of all four experimental groups when compared with the control animals. The maximum increase was noted in group IV. Again, there was a significant increase in the frequency of aortic plaques in groups II, III and IV while it was increased in coronary arteries of all the experimental animals (Gps. II, III, IV and V). Group IV monkeys showed higher frequency of plaques as compared to group V animals. Although the plaque height was increased in all the vessels of the experimental animals, significant differences were observed only in the coronary arteries of group II monkeys and in intra-cranial cerebral vessels of group III animals. This study shows that vasectomy per se tends to increase atherosclerosis in rhesus monkeys.

Frequency and size of atherosclerotic plaques in vasectomized diabetic monkeys

Male rhesus monkeys were used to elucidate the combined effect of vasectomy and diabetes on frequency and size of atherosclerotic plaques. Four groups were made: in two, bilateral vasectomy was performed, and the other two were subjected to sham vasectomy. Half of the vasectomized and sham-vasectomized monkeys were made diabetic by intravenous injection of alloxan. The animals were observed for a period of one year. Clinical examination revealed bilateral cataract in 40% of the diabetic animals. Marked hyperglycemia along with significant increase of serum triglycerides and free fatty acids was noted in diabetic monkeys. Vasectomy per se did not alter serum lipid levels and overall atherosclerotic plaque score in nondiabetic monkeys. However, the combination of vasectomy with diabetic state led to significant increase of overall atherosclerotic plaque score in coronary and renal arteries.

Spontaneous cholesterol movement between lipid vesicles and monkey small intestinal brush border membrane

[14C]Cholesterol movement between egg phosphatidylcholine-cholesterol lipid vesicles and vesicles prepared from monkey small intestinal brush border membrane (BBMV) was studied in physiological buffer at 37 degrees C. The rate of cholesterol transfer from sonicated unilamellar vesicles (ULV) to BBMV follows apparently first-order kinetics. Intermembrane cholesterol movement was strikingly similar in both the directions. However, from BBMV to ULV, the transfer rate was three times faster than that of ULV to brush border membrane (BBM). Similarity in the rate constant was observed when cholesterol transfer was studied using either large multilamellar lipid vesicles or ULV as the donor and BBMV as the acceptor membrane. Rate constant was also the same when the acceptor membrane used was either intact BBMV or ULV prepared from BBM lipids. The rate of transfer of label was not affected even when the acceptor vesicle concentration was increased over fivefold, indicating the first-order nature of the reaction. Transfer of cholesterol from ULV to BBMV was accelerated by the presence of acetone, dimethyl sulfoxide (DMSO), deoxycholate, and papain. Partially purified nonspecific lipid-exchange protein increased the rate of cholesterol transfer by about threefold. Reduction in BBM cholesterol and phospholipid content was noted by DMSO, acetone, and deoxycholate, while papain caused a small depletion of membrane protein. Cholesterol transfer is temperature dependent with an activation energy of 31 kJ X mol-1, which is almost identical in the presence or absence of nonspecific lipid-exchange protein. The molecular mechanism of intermembrane cholesterol movement is discussed in view of the kinetic data obtained.

Pathological changes in fallopian tubes following three different kinds of occlusive techniques in primates

A comparative evaluation of three different techniques (Madlener's, Wood's and Filshie Clip Mark IV) for female sterilization was carried out in adult female rhesus monkeys with the aim of finding out the efficacy and the extent of tissue damage in the fallopian tube. The severity of pathological changes would indicate the chances of future successful reversal. The experiment was carried out in two phases. In Phase-I, no post-operative antibiotics were given whereas in Phase-II in addition to post-operative antibiotics, two sham-operated controls were also kept. This study revealed that the Filshie's clip is associated with significantly (p less than 0.01-0.001) greater tissue damage of the fallopian tubes with formation of dense adhesions as compared to the Madlener's or Wood's technique. Further, Filshie's clip had slipped off from 4 tubes out of 14 tubes where it was applied.

Pyelonephritis alters the reabsorption of nutrients and brush border membrane enzymes of rat kidney

The uptake of nutrients and activities of membrane enzymes in the kidney were investigated using renal brush border membrane (BBM) vesicles in acute pyelonephritis in rats. A significant decrease (P less than 0.001) in the uptake of D-glucose and L-phenylalanine was observed in both the unobstructed right and obstructed left kidney, while there was a significant increase (P less than 0.001) in the uptake of L-alanine in the left kidney of pyelonephritic rats, demonstrating disturbances in the reabsorption of the glucose and aminoacids in the kidneys. Vmax of alkaline phosphatase, leucine-amino-peptidase and maltase was found to be decreased in the left kidney, suggesting that there was a reduction in the active enzyme molecule number. Km of alkaline phosphatase and leucine-aminopeptidase remained unchanged, while km of maltase decreased in both the right and left kidneys. An increase in the Vmax of alkaline phosphatase and leucine-aminopeptidase and substrate affinity of the maltase in the right kidney demonstrated a compensatory phenomenon for the malfunctioning of the left kidney. This is the first report demonstrating alterations in reabsorption of nutrients and BBM enzymes in experimental pyelonephritis.

Effects of 17 beta-estradiol and progesterone on intestinal digestive and absorptive functions in ovariectomized rats

The effects of low and high doses of 17 beta-estradiol and progesterone for 2 weeks on intestinal digestive and absorptive functions have been investigated in ovariectomized rats. The uptake of glucose was significantly enhanced following ovariectomy and administration of hormones restored the level of glucose uptake to that observed in sham-operated animals. Neither, the uptake of L-leucine nor calcium was affected after ovariectomy and treatment with the hormones. The activity of alkaline phosphatase (AP) of ileum was significantly elevated with the low and high doses of 17 beta-estradiol but in jejunum only at high doses. Progesterone alone did not alter AP activity but the combination of this hormone and 17 beta-estradiol significantly enhanced the jejunal and ileal AP activities. It seems that activity of AP is mainly under the control of 17 beta-estradiol. The activity of ileal disaccharidases and leucine aminopeptidase were enhanced at high doses of 17 beta-estradiol alone or in combination with progesterone whereas in the jejunum only AP activity was increased significantly. The present study indicates that 17 beta-estradiol plays an important role in regulating the activities of intestinal digestive enzymes and it is the ileal enzymes which are more prone to its action.

Aggravation of experimental atherosclerosis in vasectomized, cholesterol-fed rabbits

Rabbits were fed a stock or atherogenic diet for a period of fourteen months. Half of each group of rabbits was bilaterally vasectomized while the other half underwent sham vasectomy. The level of plasma cholesterol was significantly elevated following vasectomy in stock diet-fed rabbits. Atherogenic diet feeding caused marked elevation of plasma cholesterol in both vasectomized as well as sham-vasectomized animals. At the termination of the experiments, aortic cholesterol in stock diet-fed vasectomized rabbits remained unchanged, but this was increased in both vasectomized and sham-vasectomized atherogenic diet-fed animals. Aortic sudanophilia, atherosclerotic plaque size and coronary atherosclerosis index were significantly increased in vasectomized atherogenic diet-fed rabbits as compared to their controls. In stock diet-fed vasectomized rabbits no macroscopic or microscopic lesions were seen even in the presence of mild hypercholesterolaemia.

Effect of short-term and long-term treatment with a steroidal oral contraceptive on the intestinal absorption of nutrients in vitro in female rats

The effect of steroidal oral contraceptive (SOC), comprising megestrol acetate (5 mg/kg body weight) plus ethinyl estradiol (0.05 mg/kg body weight), administered daily by stomach tube for 5, 15, 30 and 90 days, on the intestinal uptake of nutrients such as glucose, amino acids and calcium has been investigated in vitro in female rats. The administration of SOC for 5 days did not affect the uptake of nutrients, but treatment for 15, 30 and 90 days led to a progressive and significant increase in the uptake of glucose and amino acids. The calcium uptake was increased in the groups treated for 5 and 15 days, but decreased after 30 and 90 days of treatment. Kinetic studies done on glucose uptake indicated that the steroid contraceptive might be inducing the transport carrier protein of this nutrient, as elevation in Vmax was observed in the group treated for 30 days. There was no change in brush border membrane phospholipid and cholesterol contents after 30 and 90 days of treatment, but a significant increase in phospholipid after 5 and 15 days of treatment was observed. This study suggests that SOC treatment significantly altered the intestinal absorptive functions and the effect appears to be on the carrier-mediated transport of glucose.

Influence of levamisole on lymphocytes and M. leprae in mice

Normal uninfected (N) and M. leprae infected mice (NI) were given levamisole in the dose of 2.5 mg/kg body weight. The animals were observed over a period of nine months for bacillary load, T and B cell counts and blast transformation with PHA. Significant increase in B cell counts was observed in the levamisole treated normal (NL) compared to normal control (N) group. T cell counts and blast transformation, however, remained unaffected. However, T-cell counts and blast transformation improved significantly in the infected and levamisole treated (NIL) as compared to the infected group (NI) not given levamisole. Bacillary loads remained unaltered in both, the infected (NI) and levamisole treated (NIL) group.

Trophic changes and extensive dissemination in normal mice infected with human Mycobacterium leprae

Closely bred Swiss albino normal mice (Lecca Strain) were inoculated in the footpad with M. leprae, at room temperature. The animals were harvested at 3, 6 and 9 months post inoculation, and bacillary counts were made. Trophic changes were observed in the tail-tips, ears, footpads and forepaws 12-14 months post inoculation in a group which was allowed to survive. The histopathological changes and bacillary infiltration was found in many tissues/organs. The possibility of studying this normal strain of mice as an experimental model for human leprosy has been discussed.

Humoral immunity in experimental immune carditis

An experimental model of carditis has been produced in the rhesus monkey by giving 12 weekly injections of a streptococcal membrane antigen. There was histological evidence of focal myocarditis, subendocardial infiltration with lymphomononuclear cells and in one animal myocardial granuloma formation. No valvular lesions were seen. Humoral immune responses monitored throughout the experiment showed that anti-heart antibodies appeared in circulation after the 2nd injection, attained maximal titres by the 6th injection, and thereafter the titres declined. The anti-membrane antibodies appeared slightly later and these titres kept rising till sacrifice. By the 6th injection there was evidence of complement consumption and appearance of circulating immune complexes. It is concluded that these immunological responses might have a role to play in the pathogenesis of carditis.

Effect of medroxyprogesterone acetate on the intestinal absorptive functions in protein-deficient rat

Effect of Medroxyprogesterone acetate (MPA) at a dose level of 35mg/Kg body weight per week for four weeks on the intestinal uptake of nutrients viz glucose, amino acids, (alanine and leucine), calcium and zinc has been investigated in protein-deficient female rats. The administration of MPA was found to enhance significantly the uptake of glucose and amino acids in both the pair-fed and the protein-deficient rats. In contrast, calcium uptake was depressed as a result of treatment with the drug as well as protein-deficiency. The uptake of zinc was not affected on drug administration. This steroidal contraceptive caused elevation in sodium-dependent glucose uptake, while the sodium-independent uptake remained unaltered. The kinetic parameters of glucose and leucine uptake indicate that MPA might be inducing the transport carrier protein of these nutrients as elevation in Vmax of these nutrients transport system was observed following its administration.

Alterations and reversibility of digestive and absorptive functions of rat intestine following medroxyprogesterone acetate administration

The long term (90 days) effects of medroxyprogesterone acetate (MPA) administration on the digestive and absorptive functions of the small gut have been investigated in female albino rats. The uptake of glucose and amino acids was found to be significantly increased while Ca++ uptake decreased following MPA treatment (35 mg/kg body weight). The observed increase in glucose uptake might be due to carrier mediated transport in enterocytes and not to a change in cell number. The Michaelis constant for glucose uptake was not altered by MPA. Activities of brush border membrane disaccharidases, leucine aminopeptidase and basolateral membrane enzyme Na+, K+-ATPase were significantly increased in response to MPA treatment. It was observed that these biochemical alterations caused by MPA in intestinal digestive and absorptive functions were reversible by 5 weeks after termination of the drug treatment. The action of the drug appears to closely resemble that of known effects of glucocorticoids on intestinal mucosa.

Intestinal adaptation to zinc absorption following massive small bowel resection and colon interposition in rhesus monkeys

The intestinal uptake of zinc was studied in Rhesus monkeys, after 80% small bowel resection and colon interposition in between the remnant jejunum and the ileum. The hair and serum zinc levels decreased in the early postoperative period and gradually attained normal values after three months postoperatively. A significant increase in the zinc uptake was observed in vitro, in the remnant jejunum, ileum and the grafted colon, both in six months and one year old operated monkeys, suggesting a compensatory intestinal adaptation for zinc absorption after massive small bowel resection and antiperistaltic colon interposition.

Morphological and functional changes in the gut after massive small bowel resection and colon interposition in rhesus monkeys

An experimental model of massive small bowel resection and colonic autograft in an antiperistaltic fashion in between the remnants of jejunum and ileum was developed in Rhesus monkeys. The gross morphological changes showed significant (p less than 0.001) lengthening and dilatation of the remnant jejunum, ileum and the colonic graft. Hypertrophy and hyperplasia of the mucosal and muscular layers of all the 3 segments was revealed by morphometric studies and the estimation of the nucleic acid content of the mucosa. All the 3 segments of the bowel showed a significant increase (p less than 0.001) in the uptake of D-glucose, L-alanine and L-phenylalanine when compared to the control animals. These changes were more pronounced in the animals kept for longer duration. Phlorizin was found to be inhibitory for the uptake of D-glucose in the grafted colon, suggesting the induction of an active nonelectrolyte transport process in the autografted colon. The present study suggests that the colonic loop adapts itself to the functions of the small bowel along with the compensatory adaptation of the remnant jejunum and the ileum for the loss of absorptive surface secondary to massive small bowel resection .