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Biomedical subjects

A V Rao

Publications and source records attributed to A V Rao.

At least 19 recordsLinked to original sources
PubMed1992

Effect of dietary oxidized cholesterol on azoxymethane-induced colonic preneoplasia in mice.

The effect of cholesterol and oxidized cholesterol on azoxymethane-induced colonic preneoplasia was evaluated in C57BL/6J and BALB/cJ mouse strains. Mice were fed either a control AIN 76 semisynthetic diet or the control diet supplemented with 0.1% or 0.3% cholesterol, or 0.1% or 0.3% oxidized cholesterol for an 8-week period. For the first 4 weeks of the experiment, mice received weekly injections of azoxymethane (5 mg/kg body weight). Dietary cholesterol increased fecal concentrations of neutral and acid sterols. A dose-response relationship was observed in both mouse strains between the level of dietary cholesterol or oxidized cholesterol and formation of preneoplastic aberrant crypt foci. Enhanced cell proliferation along with alterations in several crypt morphometric parameters were also observed. These anomalies were enhanced to a greater extent by oxidized cholesterol. This data shows a very strong effect of cholesterol in enhancing the development of preneoplastic lesions in chemically induced cells. It also demonstrated that the state of oxidation of cholesterol influences colonic preneoplasia. This factor has been overlooked in previous animal experiments.

Analysis of Variance↗
PubMed1992

Dietary cholesterol enhances the induction and development of colonic preneoplastic lesions in C57BL/6J and BALB/cJ mice treated with azoxymethane.

The effect of dietary cholesterol on the induction and development of colonic precursor lesions was determined in two mouse strains, C57BL/6J and BALB/cJ, which differ in their metabolism of cholesterol. Mice were randomized into four groups and fed a cholesterol-free or a 1.25% cholesterol diet during and/or subsequent to four weekly injections of azoxymethane (5 mg/kg body wt.). Dietary cholesterol significantly increased the number of aberrant crypt foci (P less than 0.0001), enhanced cell proliferation (P less than 0.0001) and induced alterations in the proliferative pattern and crypt morphometrics in the colonic epithelium of both mouse strains. While C57BL/6J mice developed a greater number of aberrant crypt foci than BALB/cJ mice (p less than 0.0001), a significant diet-strain interaction effect was not observed. The present results indicate that dietary cholesterol enhances the induction and development of chemically-induced colonic precancerous lesions but this process is not affected by genetic differences in cholesterol metabolism, as represented by the two strains of mice studied.

Animals↗
PubMed1992

Synthesis of lysine-containing fragments of the Proteus mirabilis O27 O-specific polysaccharide and neoglycoconjugates therefrom.

Amide-linked lysine mono- and di-uronic acid fragments of the O-specific polysaccharide from P. mirabilis O27 have been synthesised. N epsilon-Boc-L-lysine tert-butyl ester was condensed with 2-azidoethyl glycosides of glucuronic acid and beta-D-GlcpNAc-(1----3)-beta-D-GlcpA. Transformation of the products into 2-acrylamidoethyl glycosides, followed by deprotection using trifluoroacetic acid, gave the target monomers that were converted into high-molecular-weight copolymer-type neoglycoconjugates.

Carbohydrate Sequence↗
PubMed1992

Ultrafiltration membranes for the separation of catalyst and products in homogeneous catalysis systems.

Results of preliminary studies on concentration by ultrafiltration and reuse of a Ru(III)EDTA complex in homogeneous catalysis are reported. A method of preparation and selection of conditions of making cellulose acetate membranes for concentrating Ru(III)EDTA is described. At an operating pressure of 75 psig (517 kPa), the above catalyst can be concentrated to seven to eight times its initial concentration. The membrane used exhibits a separation of about 97.5% for the complex with a permeate flow rate of about 3-6 gallons per sq. ft per day. The catalyst activities were determined for two reactions, viz. hydroformylation of 1-hexene and carbonylation of ammonia for five cycles of concentration followed by reuse. The experimental data indicated that the catalyst concentration by ultrafiltration for subsequent reuse is simple and attractive and can provide potentially energy saving alternative to the cumbersome conventional separation processes associated with the recovery of catalysts in homogeneous catalysis.

Biotechnology↗
PubMed1992

Dose-dependent effects of dietary phytosterol on epithelial cell proliferation of the murine colon.

Phytosterols are a group of compounds in plants that have been found to inhibit tumour development and decrease enhanced colonic epithelial cell proliferation in carcinogen-treated rats. The mechanism by which phytosterols may inhibit tumour development and alter cell proliferation is unknown. However, studies have shown that dietary phytosterol intake may alter levels of certain promoters in the colonic lumen, leading to altered levels of colonic epithelial cell proliferation. In this study, the effect of dietary phytosterol on the proliferative status of the intestinal epithelium was investigated in mice. Inbred C57B1/6J mice were fed semi-synthetic diet (control); 0.1% cholic acid, 0% phytosterol (cholic acid control); and cholic acid plus 0.3, 1.0 or 2.0% phytosterol. Dietary cholic acid significantly increased colonic epithelial cell proliferation and the highest labelled cell position by 92 and 35%, respectively. Phytosterol significantly reduced the enhanced labelling index and the position of the highest labelled cell in a dose-dependent manner. Mitotic index was also reduced significantly by phytosterol but not in a dose-dependent manner. The results of this study indicate that phytosterol influences the colonic epithelial cell morphometrics, that are important preneoplastic events in colon carcinogenesis, and may thus contribute to a reduced risk of cancer.

Administration, Oral↗
PubMed1992

Dietary cholesterol enhances preneoplastic aberrant crypt formation and alters cell proliferation in the murine colon treated with azoxymethane.

The effect of dietary cholesterol on the development of colonic preneoplastic aberrant crypts, as well as its influence on the proliferative status of the intestinal epithelium, was investigated in mice exposed to the chemical carcinogen azoxymethane. Two strains of mice, C57BL/6J and BALB/cJ, were fed a semisynthetic diet containing 0% (control), 1.25%, or 5.00% cholesterol for eight weeks. During the first four weeks of the experiment, mice were given weekly injections of azoxymethane. Cholesterol supplementation significantly increased the formation of aberrant crypts (p less than 0.0001), enhanced the rate of cell proliferation (p less than 0.0001), altered the cell proliferative pattern, and increased crypt height (p less than 0.05) and the total number of cells per crypt (p less than 0.01) in the colonic epithelium of both mouse strains. C57BL/6J mice developed a greater number of aberrant crypts (p less than 0.0001). However, a diet-strain interaction was not observed. The results of this study indicate that dietary cholesterol enhances colon carcinogenesis in the murine colon and therefore may be an important factor in the etiology of large bowel cancer in humans.

Analysis of Variance↗
PubMed1992

The role of dietary phytosterols in colon carcinogenesis.

Epidemiological and experimental studies have shown that increased intake of plant foods and decreased meat consumption are correlated with a decreased risk for colon cancer. Many components of plant foods are suggested to mitigate colon carcinogenesis, including vitamins, minerals, and dietary fiber. Phytosterols are a common component of plant foods consumed in relatively large quantities by vegetarians, who are at lower risk for colon cancer development than individuals on a Western diet low in phytosterols. In addition, phytosterols have been shown experimentally to inhibit colon cancer development. Dietary cholesterol, although structurally similar to the phytosterols, is correlated etiologically to the incidence of colon cancer, with changes in serum cholesterol levels and fecal bile acid profiles suggested to increase susceptibility to colon tumorigenesis. The objective of this paper is to discuss the effect of dietary phytosterols on cholesterol and bile acid metabolism and how these effects may lead to a decreased risk for colon cancer development.

Animals↗
PubMed1992

Role of rifampin and clofazimine ointments in the treatment of leprosy.

The use of rifampin and clofazimine ointments alone and in combination over the patches of tuberculoid patients had a beneficial effect. In combination (rifampin and clofazimine), erythema, inflammation, and edema are considerably reduced. For some of the cases with a recent appearance of a patch, the patch completely disappeared. It is suggested that topical therapy with rifampin and clofazimine ointments would be economical and beneficial in tuberculoid leprosy.

Clofazimine↗
PubMed1991

Tridimensional ultrastructure of perfusion fixed gastrointestinal epithelial cells by high resolution scanning electron microscopy.

Improvements in the design of modern scanning electron microscopes (SEM) and new methods of specimen preparation incorporating chemical removal of the cytosol and cytoskeleton, now make it possible to view cells and their organelles in three dimensions (3D) at high magnification. In this experiment, high resolution SEM (HRSEM) utilizing new methods of tissue preparation was used to study the intracellular structures of the mouse ileum. In addition, in vivo intestinal perfusion was used to further enhance cellular preservation. Using these modifications it was possible to visualize, in 3D, the fine structure of intestinal epithelial cells and intracellular organelles such as the nucleus, mitochondria, endoplasmic reticulum, and Golgi complex, as well as microvilli and cell membrane. Whole mitochondria appeared as irregularly shaped organelles which contained tubular cristae. Plate-like cristae were not observed. The brush border was found to be closely packed array of cylindrical projections. The extensive folding and structural intricacy of lateral cell membranes between absorptive cells could only be appreciated by viewing this tissue with 3D HRSEM. The use of HRSEM to study 3D ultrastructure of cells and their organelles will improve our understanding of the structure-function relationships in both the healthy and diseased gastrointestinal tract.

Animals↗
PubMed1991

Synthesis of glycuronamides of amino acids, constituents of microbial polysaccharides and their conversion into neoglycoconjugates of copolymer type.

Glycopyranosiduronic acids, amidically linked to amino acids (alanine, serine, threonine, and lysine) were prepared. O-tert-Butyl and N epsilon-tert-butyloxycarbonyl protected amino acid tert-butyl esters were used in ethyl 2-ethoxy-1,2-dihydroquinoline-1-carboxylate promoted condensation with 2-azidoethyl glycosides of glucuronic and galacturonic acid. Reduction of the azido-function followed by N-acryloylation and removal of blocking groups with trifluoroacetic acid gave the target monomers. These were converted into neoglycoconjugates of copolymer type, potentially useful for immunochemical studies.

Amides↗
PubMed1991

Antepartum cultures for Ureaplasma urealyticum are not useful in predicting pregnancy outcome. The Vaginal Infections and Prematurity Study Group.

To test the hypothesis that genital colonization with Ureaplasma urealyticum would predict adverse pregnancy outcome, 4934 women from five medical centers were evaluated for vaginal colonization with U. urealyticum between 23 and 26 weeks' gestation and followed up to delivery. U. urealyticum colonization was associated with maternal age, parity, racial-ethnic group, martial status, income, education, smoking, number of sexual partners, and colonization with Trichomonas vaginalis, Mycoplasma hominis, and bacterial vaginosis. After adjustment for medical and sociodemographic factors in a multivariate analysis, there was no difference in the mean birth weight or proportion of low-birth-weight infants delivered by women who carried U. urealyticum and those who did not. U. urealyticum colonization at 23 to 26 weeks was not associated with preterm rupture of membranes, preterm labor, or preterm delivery. A positive vaginal culture for U. urealyticum in midgestation does not predict those women at risk for preterm labor, preterm delivery, preterm premature rupture of membranes, or delivery of a low-birth-weight infant.

Adolescent↗
PubMed1991

A randomized placebo-controlled trial of erythromycin for the treatment of Ureaplasma urealyticum to prevent premature delivery. The Vaginal Infections and Prematurity Study Group.

Ureaplasma urealyticum has been associated with low birth weight and histologic chorioamnionitis and it is a frequent isolate from the chorioamnion of patients who are delivered prematurely. In prior clinical trials using antibiotics active against U. urealyticum, antibiotic treatment was associated with reduced prematurity and increased mean birth weight. In this multicenter, randomized, double-blind clinical trial, pregnant women with U. urealyticum were treated with 333 mg of erythromycin base or placebo three times daily, starting between 26 and 30 weeks' gestation and continuing through 35 completed weeks of pregnancy. Women with urinary tract infection or Neisseria gonorrhoeae infection were excluded from the trial, and women with Chlamydia trachomatis or group B streptococci were excluded from these analyses. Erythromycin did not eliminate U. urealyticum from the lower genital tract. There were no significant differences between erythromycin- and placebo-treated women in infant birth weight or gestational age at delivery, in frequency of premature rupture of membranes, or in neonatal outcome.

Adult↗
PubMed1991

Long-term effect of Bifidobacteria and Neosugar on precursor lesions of colonic cancer in CF1 mice.

This investigation was undertaken to study the role of Bifidobacteria and bifidogenic factor Neosugar in the process of 1,2-dimethylhydrazine-induced colonic carcinogenesis in CF1 mice. Intestinal colonization and selective proliferation of Bifidobacteria were achieved by oral administration of indigenous Bifidobacteria and the incorporation of 5% Neosugar in the diet of animals. The Bifidobacteria were isolated from the feces of CF1 mice and were identified to be Bifidobacterium pseudolongum biovar b. This incidence of aberrant crypts and foci were significantly lower 38 weeks after the last injection of the carcinogen in animals fed Bifidobacteria than in animals treated with the carcinogen alone. The aberrance also appeared to be confined to the more distal end of the colon in animals fed bifidogenic diet. Such changes in the precursor lesions of colonic carcinogenesis are presumably due to the increase in the number of Bifidobacteria and their acidifying action in the lower intestinal tract of the animals.

Animals↗
PubMed1991

Specific types of colonic fermentation may raise low-density-lipoprotein-cholesterol concentrations.

To assess the effects of increased colonic fermentation on serum lipids, eight healthy volunteers were placed on two identical 2-wk metabolic diets, one of which was supplemented with lactulose (18-25 g/d). Lactulose raised day-long concentrations of breath hydrogen and serum glutamine as indicators of increased colonic fermentation by 78 +/- 13% (P less than 0.001) and 24.7 +/- 9.5% (P less than 0.05), respectively). Unexpectedly, however, fasting serum total and low-density-lipoprotein cholesterol and apolipoprotein B concentrations were higher at 2 wk by 8.9 +/- 1.5% (P less than 0.001), 10.9 +/- 2.2% (P less than 0.005), and 18.9 +/- 5.9% (P less than 0.02), respectively, compared with the control diet. With lactulose, mean free fatty acid concentrations were reduced over the day by 19.5 +/- 5.9% (P less than 0.02), with no change in mean day-long blood glucose, serum insulin, or C-peptide concentrations. We conclude that certain rapidly fermented substrates may raise rather than lower serum lipids, possibly through increasing the amount of acetate absorbed from the colon.

Acetates↗
PubMed1991

Propionate lowers blood glucose and alters lipid metabolism in healthy subjects.

Incorporation of 3.3 g sodium propionate per 50 g available carbohydrate portion of bread reduced acutely the blood glucose response area in six healthy volunteers by 47.6 +/- 12.1% Similarly, in vitro digestibility was reduced by 47.4 +/- 1.1% (P less than 0.01). One week of dietary supplementation with 9.9 g sodium propionate in bread/d reduced the blood glucose area in comparison with standard propionate-free bread by 38.0 +/- 8.7% (P less than 0.05), but increased fecal bulk by 28.3 +/- 8.7% (P less than 0.05) and anaerobic microflora by 0.564 +/- 0.165 X 10(6)/g feces (P less than 0.05), specifically as bifidobacteria. Day-long breath hydrogen concentrations did not increase after 1 wk on propionate bread but methane production increased in the three methane producers. Although lipid changes were not significant, five subjects showed reduced high-density-lipoprotein and increased triglyceride concentrations, both of which correlated with increased fecal weight (P less than 0.05). Because propionate reduces the rate of starch digestion, studies using oral propionate must take into account its action as an enzyme inhibitor.

Adult↗
PubMed1991

A multi-centre comparative study of diclofenac sodium and a dipyrone/spasmolytic combination, and a single-centre comparative study of diclofenac sodium and pethidine in renal colic patients in India.

A single-blind, randomized clinical trial was carried out to compare the analgesic effectiveness in patients with renal colic of single intramuscular doses of diclofenac sodium (75 mg) versus a dipyrone (1 g)/spasmolytics combination, and diclofenac sodium (75 mg) versus pethidine (75 mg). The first study involved three centres, the second study one centre. In total, 107 patients were treated with diclofenac sodium, 85 with dipyrone/spasmolytics, and 25 with pethidine. Assessments were made during the first hour after drug administration of the degree of pain relief, the severity of pain using a visual analogue scale, and the duration of analgesia. A global assessment of treatment efficacy was made by the participating physicians at the end of the study period. Patients treated with diclofenac sodium showed an earlier onset of analgesia and a higher incidence of total pain relief compared to those treated with dipyrone/spasmolytics or pethidine. Although the mean duration of analgesia was only slightly greater in the diclofenac sodium group than in the dipyrone/spasmolytics group, a significantly longer effect was seen when diclofenac sodium was compared with pethidine (p less than 0.01). Pain severity assessments revealed that diclofenac sodium caused a significantly greater improvement in pain after 60 minutes compared to dipyrone/spasmolytics (p less than 0.05) and after 30 minutes compared to pethidine (p less than 0.05). Global efficacy assessments by the physician rated diclofenac sodium as significantly superior to dipyrone/spasmolytics (p less than 0.01) and pethidine (p less than 0.001). Moreover, diclofenac sodium was better tolerated than either of the comparative treatments. The results indicate that intramuscular diclofenac sodium is a useful alternative to the drugs commonly used in India in the treatment of renal colic.

Adolescent↗
PubMed1991

Behaviour change in HIV infected subjects following health education.

A total of 85 HIV seropositive subjects among consecutive new registrants in the STD Department were given health education measures directed to avoiding high risk behaviours and also the events with a high potential for transmission of infection. The emphasis was on the use of condoms, discontinuing promiscuity, abstaining from homosexual acts and avoidance of pregnancy and advice against marriage for those contemplating it. The Health Education Programme was delivered individually to each subject over two or three sessions, each lasting for 30 to 45 min. At the time of follow up (one to 24 months) 42 per cent of subjects had become non-promiscuous. There was a good compliance on advice against marriage and pregnancy. Seven infants born during the follow up period were seronegative. The use of condom was not found to be acceptable. The prostitutes comprised the most resistant group to education. Among the factors that influenced the behaviour change favourably was the absence of earlier STD or a short duration of the current STD. Literacy, marital status, awareness of AIDS did not influence the outcome of education. The study demonstrated the feasibility of health education at individual level in the clinical setting of an STD Department. A longer follow-up may indicate the sustainability of behaviour change in the subjects.

Adult↗