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Biomedical subjects

S R Naik

Publications and source records attributed to S R Naik.

At least 37 records · Page 2Linked to original sources

Endosonographic, endoscopic, and histologic evaluation of alterations in the rectal venous system in patients with portal hypertension.

BACKGROUND: Colorectal varices and congestive rectopathy or colopathy have been erratically reported in patients with portal hypertension. The clinical importance of these entities has not been described. We assessed the changes in the venous system of the rectum by endoscopy and rectal endosonography (EUS). We also assessed the role of factors such as etiology of portal hypertension, grade of esophageal varices, sclerotherapy, and liver disease severity on the occurrence of these vascular changes. METHODS: We studied changes in the venous system of the rectum using endoscopy and EUS in 60 patients with portal hypertension (cirrhotic 41, noncirrhotic 19). Ten patients with irritable bowel syndrome and 6 patients with hemorrhoids served as controls. Rectal varices were classified as tortuous, nodular, and tumorous. Corresponding appearances on rectal EUS were classified as single or discrete multiple, multiple, and innumerable submucosal veins, respectively. Evidence of congestive rectopathy was also recorded. RESULTS: Prevalence of rectal varices was 43.3% on endoscopy (73% tortuous, 19% nodular, and 8% tumorous) and 75% on EUS (p < 0.0005). The latter showed corresponding appearances of submucosal veins in 25 of 26 patients and detected submucosal veins not identified at endoscopy in 19 other patients. Congestive rectopathy was found in 38.3% of patients. Multiple small dilated vessels in the submucosa were seen in 23.3% patients on rectal EUS. The development of these vascular changes was significantly influenced by sclerotherapy, but not by higher grade of esophageal varices, the etiology of portal hypertension, or severity of liver disease. CONCLUSIONS: Changes in the rectal venous system are common, with rectal EUS being superior to endoscopy in detecting early, as well as florid, changes.

Adolescent↗

Moderate protective effect of 6-MFA, a microbial metabolite obtained from Aspergillus ochraceus on immunological liver injury in mice.

Hepatoprotective effect of 6-MFA, obtained from fungus Aspergillus ochraceus ATCC 28706, was evaluated by employing three different immunological liver injury mice models. The first liver injury model was induced by injecting anti-basic liver protein (BLP) antibody into mice previously immunised with rabbit IgG (RGG). The other models were simulated by injecting antiliver specific protein (LSP) antibody or by injecting bacterial lipopolysaccharide (LPS) into mice pretreated with Corynebacterium parvum (C. parvum). 6-MFA treatment inhibited the increased transaminases (GOT and GPT) activities and showed a tendency to inhibit the histopathological changes of the liver in all the models studied. Furthermore, 6-MFA treatment inhibited deoxycholic acid induced transaminase release from cultured rat hepatocytes in vitro, but failed to affect the formation of hemolytic plaque forming cells in immunised mice spleens and hemolytic activity of guinea pig complement in immunohemolytic reaction. Our findings, therefore, suggested that the moderate hepatoprotective effect of 6-MFA could be related to it's protective effect on hepatocyte plasma membrane rather than the direct inhibitory effects on the antibody formation and/or complement activity.

Animals↗

Experimental studies (in vitro) on polyene macrolide antibiotics with special reference to hamycin against Malassezia ovale.

Hamycin activity (in vitro) against Malassezia ovale was studied and compared with old and newly discovered polyene antifungal antibiotics. Hamycin showed a marked anti-M. ovale activity which was enhanced in the presence of divalent cations like Cu++ and Zn++. Furthermore, the absorption of hamycin onto the cell membrane or cell surface of M. ovale was also increased in the presence of divalent cations. It is suggested that hamycin alone or along with metal ions, specifically Cu++ may be useful clinically in the treatment of dandruff or seborrheic dermatitis.

Amphotericin B↗

Preparation and activity of some novel organo-metallic complexes against Helicobacter pylori.

Some novel organo-metallic complexes were prepared by complexing the antibiotics erythromycin (CAS 114-07-8), doxycycline (CAS 564-25-0), ciprofloxacin (CAS 85721-33-1) and amoxicillin (CAS 26787-78-0) with bismuth citrate and their antibacterial activity against Helicobacter pylori and other micro-organisms were investigated. Amoxicillin-bismuth citrate had the strongest activity against H. pylori with a lowest minimum inhibitory concentration of 0.007 mg/l. The complexes exhibited moderate activity against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Bacillus subtilis. The findings suggest that the activity of these organo-metallic complexes might be specifically directed against H. pylori.

Anti-Bacterial Agents↗

Preparation, relative toxicity and therapeutic efficacy in mice and rats of liposomal HA-1-92, a new oxohexaene polyene macrolide antibiotic.

HA-1-92, a new polyene oxohexaene macrolide antibiotic isolated from Streptomyces CDRIL-312, was incorporated into liposomes containing phosphotidyl choline and cholesterol. The liposomal incorporated HA-1-92 considerably decreased toxicity when compared with free HA-1-92 in mice. Liposomal HA-1-92 showed improved pharmacokinetic profiles in rats. When administered to aspergillosis- and cryptococcosis-infected Balb/c mice, liposomal HA-1-92 showed increased antifungal activity, compared with free HA-1-92, with improved survival rate and decreased colony-forming units in lung, liver, spleen and kidney. These results suggest that liposomal HA-1-92 is more effective than free HA-1-92 in controlling experimental aspergillosis and cryptococcosis in Ba1b/c mice.

Animals↗

Vaccine potential of 56-66 kDa protease secreted by Entamoeba histolytica.

Excretory/secretory (ES) antigens and sub-cellular fractions of E. histolytica (HM1:IMSS strain) were tested for the presence of common proteases using substrate gel electrophoresis. We obtained two E. histolytica proteases (56-66 kDa and 29 kDa) from ES material, soluble components and plasma membrane. Protease 56-66 kDa from ES antigen was selected for immunizing hamsters because it gave a consistent broad band. We observed 62.5 per cent protection in immunized animals, compared to 0 per cent in unimmunized controls. Although all vaccinated golden hamsters showed high antibody response, there was no correlation between antibody titres and protection. 56-66 kDa ES protease could thus prevent disease and could be a candidate molecular vaccine against amoebiasis.

Amebiasis↗

Influence of alkali-treated cornsteep liquor containing medium on protein A production by Staphylococcus aureus.

Staphylococcus aureus cultivated in liquid media containing untreated cornsteep liquor (CSL) and alkali-treated CSL produced similar biomass yields (6.5-6.9 g/L). However, contents of protein A in the biomass was 0.5% and 1.56% for untreated CSL and treated CSL, respectively. Addition of treated CSL at 20 g/L achieved optimal enhancement of protein A production (0.11 g/L). Probable factors associated in treated CSL for the enhanced protein A production are discussed.

Culture Media↗

Protection by Rhinax in various models of ulceration in rats.

The effect of Rhinax on gastric damage in different animal models including gastric ulceration induced by a necrotic agent such as 0.6 N HCl, indomethacin, and intragastric distension was studied. Treatment with Rhinax at a dose of 160 mg/kg protected gastric mucosa against the damage induced by oral administration of indomethacin and intragastric distension. The volume and acidity of gastric juice in pyloric ligated rats was reduced by Rhinax. It also significantly promoted gastric mucus secretion in normal animals. On the basis of these observations, we conclude that Rhinax possesses anti-ulcer activity and that the observed activity may be due to the modulation of defensive factors by improvement in gastric cytoprotection.

Animals↗

Oesophageal motility and gastro-oesophageal reflux: effect of variceal eradication by endoscopic sclerotherapy.

Endoscopic injection sclerotherapy (EIS) is known to produce oesophageal structural and motility changes; however, alterations in frequency and severity of gastro-oesophageal reflux (GER) following EIS have not been investigated in detail. We studied 22 patients with cirrhosis and oesophageal varices before EIS and 26 after variceal eradication with intravariceal EIS using manometry and 24 h pH monitoring. The post-EIS group had reduced oesophageal sphincter pressure (19.2+/-11.4 vs 26.1 +/-16.4 mmHg, P< 0.05) and slower velocity of oesophageal peristalsis (2.47+/-0.71 vs 3.06+/-0.77 cm/s, P< 0.01) than the pre-EIS patients. There was no difference in the amplitude or duration of the contraction. Abnormal contraction wave-forms were observed more frequently in post-EIS than in the pre-EIS patients (3/22 vs 12/26, P< 0.05). Various quantitative parameters for GER were not increased in post-EIS compared with pre-EIS patients. Abnormal GER was present in nine of 21 pre-EIS and eight of 17 post-EIS patients (no significant difference). These results suggest that although persistent oesophageal motility changes are frequent after intravariceal EIS, these do not lead to a significant increase in GER.

Adult↗

Significance of elevated IgG anticardiolipin antibody levels in patients with Budd-Chiari syndrome.

OBJECTIVES: Budd-Chiari syndrome (BCS) is characterized by hepatic venous outflow obstruction. Though hypercoagulable states are implicated in the causation of BCS, the etiology remains unknown in most cases. Presence of anticardiolipin antibodies (aCL) is a known cause of hypercoagulable state. We therefore studied the frequency of IgG aCL in BCS. METHODS: Sera were obtained from 19 patients with BCS, 50 healthy controls, 18 age- and gender-matched patients with cirrhosis, and 15 patients with acute viral hepatitis. IgG aCL levels were measured using a solid-phase enzyme immunoassay. Values exceeding mean + 2 SD of healthy controls were taken as abnormal. RESULTS: Mean +/- SD IgG aCL levels (GPL units) in the four groups were: healthy controls, 6.3 +/- 4.4; BCS, 13.8 +/- 13.3 (p < 0.05, compared with healthy controls); cirrhosis, 15.1 +/- 14.9 (p < 0.05, compared with healthy controls and p = ns, compared with BCS patients); and acute viral hepatitis, 5.0 +/- 2.5 (p = ns, compared with healthy controls). The levels in BCS and cirrhosis patients were similar (p = ns). The number of patients with elevated aCL was: healthy controls, 3/50; BCS, 6/19; cirrhosis, 7/18; and acute viral hepatitis, 0/15. The number of patients with elevated IgG aCL was significantly higher among patients with BCS and cirrhosis, compared with controls (p = 0.03 and p = 0.002, respectively). CONCLUSIONS: Patients with BCS had higher IgG aCL levels than healthy controls. However, as aCL levels were also elevated in patients with cirrhosis, the pathogenetic role of IgG aCL in the causation of BCS is doubtful.

Acute Disease↗

Relationship of manometric findings to symptomatic response after pneumatic dilation in achalasia cardia.

BACKGROUND: Achalasia cardia is usually treated by pneumatic dilation or surgical esophagomyotomy. The role of esophageal manometry for objective assessment of symptom response is controversial. AIM: To study the relationship between symptoms and manometric parameters before and after pneumatic dilation in patients with achalasia cardia. METHODS: Sixteen patients with achalasia cardia underwent esophageal manometry before and after undergoing pneumatic dilation. At each time, lower esophageal sphincter (LES) pressure and mean basal esophageal-gastric pressure gradient (MIEP-MIGP) were measured. RESULTS: Good symptom response was obtained in 12 of 16 patients. Median (range) LES pressure fell from 42 (17-51) mmHg to 18 (8-39) mmHg in those patients with a good response, and from 51 (25-68) mmHg to 29.5 (23-42) mmHg in those who responded poorly. Mean intraesophageal pressure fell below mean intragastric pressure in both the groups. CONCLUSIONS: Esophageal manometry does not correlate with symptom improvement after pneumatic dilation in achalasia cardia. Dysphagia may persist in spite of reversal of the MIEP-MIGP gradient.

Adolescent↗

Proteinase activity & virulence of Entamoeba histolytica on passage through hamster liver.

This study was undertaken to determine the enzymatic differences in the process of increasing the degree of virulence in E. histolytica successively passaged in hamster liver. Substrate gel electrophoresis was used to compare proteinase banding patterns under reducing conditions from whole cell lysates of one axenic E. histolytica (strain HM1:IMSS) and five xenic isolates of the same strain of E. histolytica passaged five times through hamster liver. Trophozoites successively passaged in hamster liver showed in supernatants, major bands in the 56-97 kDa region whereas only the axenic strain produced additional band at 34 KDa. Inoculation of amoebic trophozoites into hamster led to progressive increase in proteinase activity of supernatants as well as increased virulence of amoebae; proteinase activity of amoebae showed an excellent correlation with their virulence. All the infected animals died when activity of proteinase was 0.152 mg of protein.

Animals↗

Effect of rhinax on bacterial lipopolysaccharide induced endotoxemia in rats.

Administration of lipopolysaccharide (LPS) at 3 mg/kg, i.p. in rats resulted in reduced food intake, febrile hyperthermia, decreased body weight and reduced muscle performance in treadmill tests. It also induced some biochemical changes like increased serum levels of transaminases, acid phosphatase, pseudocholinesterase, free fatty acids and decreased blood glucose and liver glycogen levels. Rhinax (RHX), a herbal formulation, at 160 mg/kg, p.o. improved muscle performance but had no effect on the elevated temperature or the reduced body weight of rats weakened by LPS. It also normalised various biochemical alterations induced by LPS. The results of these studies indicate efficacy of RHX as an antifatigue agent to improve muscular performance.

Animals↗

Lack of in vitro lymphoproliferative response to hepatitis B surface antigen in healthy vaccine recipients.

A majority of HBsAg vaccine recipients show good anti-HBs antibody responses but poor antigen specific lymphoproliferative responses. We investigated the basis for this poor in vitro antigen specific proliferative responsiveness in vaccinees who had received the standard three dose schedule (0, 1 and 6 months) of plasma derived HBsAg vaccine. Peripheral blood mononuclear cells (PBMC) from 26 of 29 (89.7%) vaccinees failed to show lymphoproliferative responses to HBsAg in spite of having a very good anti-HBs antibody response (geometric mean titre 3154 IU/1). The mitogen (phytohaemagglutinin, PHA) and antigen (purified protein derivative, PPD) driven lymphoproliferative responses in these individuals were normal. Addition of exogenous recombinant interleukin-2 (rIL-2) along with HBsAg had no effect in the response to HBsAg in six of nine vaccinees, who were tested six months after the third vaccine dose or in four unvaccinated controls. However, in three vaccinees who did not have lymphoproliferative response to HBsAg alone, addition of exogenous rIL-2 resulted in a synergistic response. These data suggest that HBsAg reactive cells are few in the peripheral circulation of a majority of individuals following the standard three dose schedule of vaccination and addition of exogenous rIL-2 induces a response only in a subgroup of individuals. The inability of HBsAg to induce a T cell proliferative response may have implications for the maintenance of protective immunity and immunological memory following vaccination.

Adult↗

Effect of bacterial association on virulence of Entamoeba histolytica to baby hamster kidney cell monolayers.

Axenic E. histolytica trophozoite strain NIH:200 and HMI:IMSS when co-associated with aerobic bacteria Escherichia coli strain K12 and serotype 056 showed marked increase in virulence as observed by destruction of baby hamster kidney (BHK) monolayers. However, when incubated with anaerobic bacterial strains Clostridium perfringens and Bacteroides fragilis virulence remained unaltered. Further, adherence of E. histolytica to BHK monolayer was found to be mediated by N-acetyl-D-galactosamine.

Acetylgalactosamine↗

Assessment of enzyme linked immunosorbent assay based diagnostic kits (Toxokit-G and Toxokit-M) for the detection of IgG and IgM antibodies to Toxoplasma gondii in human serum.

An enzyme linked immunosorbent assay (ELISA) using penicillinase was developed in the form of diagnostic kits (Toxokit-G and Toxokit-M) for the detection of IgG and IgM antibodies to Toxoplasma gondii. The performance of both the kits was compared with commercially available diagnostic kits, i.e. Enzygnost-Toxoplasmosis/IgG (Behring Co., Germany), TOXOTEK-G (Flow Lab., U.K.) and Toxoplasma IgM Microassay (Diamedix Corp., U.S.A.) by testing toxoplasma-suspected human serum samples. The results indicate a good reliability between these diagnostic kits. Toxokit-G has 86.66 and 96.05% sensitivity and specificity respectively. The main advantage of Toxokit-G is that the end result can be assessed visually without using sophisticated instruments. Toxokit-M has 100% sensitivity and specificity and test results were not affected by the presence of antitoxoplasma IgG antibodies, rheumatoid factor or antinuclear antibodies.

Animals↗