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Biomedical subjects

S R Naik

Publications and source records attributed to S R Naik.

At least 19 recordsLinked to original sources
PubMed2003

High frequency of hepatitis B virus infection in patients with beta-thalassemia receiving multiple transfusions.

BACKGROUND AND OBJECTIVES: Hepatitis B virus (HBV) may occasionally be transmitted through transfusion of blood units that are hepatitis B surface antigen (HBsAg) negative but HBV DNA positive. Children with beta-thalassemia are particularly susceptible to HBV because they receive multiple blood transfusions. These children have high infection rates despite vaccination against HBV. Post-vaccination infections may be a result of viruses harbouring surface (S)-gene mutations (e.g. G587A) in a region critical for reactivity to antibody to hepatitis B surface antigen (anti-HBs). The true prevalence of HBV in individuals with beta-thalassemia has not been studied previously. PATIENTS AND METHODS: Seventy patients with beta-thalassemia (median age 6 years; range 8 months to 22 years; 49 male), who had received seven to 623 (median 61) units of blood each and three doses (10/20 micro g) of HBV vaccine (Engerix B) before presentation to us, were included in the study; 50 of the 70 patients had received transfusions prior to vaccination. Enzyme-linked immunoassay for serological markers [HBsAg, antibody to hepatitis B core antigen (anti-HBc) and quantitative anti-HBs] and polymerase chain reaction (PCR) followed by Southern hybridization for molecular detection of hepatitis B, was performed on all samples. The PCR-amplified product was cloned, sequenced and the nucleotide and deduced amino acid sequences for the HBV S and polymerase (P) genes were analysed for mutations. RESULTS: Four of 70 (5.7%) individuals with beta-thalassemia were HBsAg positive and 14 (20%) were anti-HBc positive. The prevalence of serological markers increased with number of transfusions (P < 0.01). Of 70 patients, 53 (75.7%) had an anti-HBs titre of > 10 IU/l following vaccination and 17 (24.3%) were non-responders (< 10 IU/l); 22 (31.4%) of the 70 were DNA positive. The frequency of HBV infection in beta-thalassemia was similar in vaccine responders and non-responders. The virus was of subtype ayw (genotype D) in the five DNA-positive samples in which a 388-nucleotide region of the S gene was sequenced. Mutations occurred at 13 positions in the S gene and at 10 positions in the P gene. Hydrophobicity plots revealed differences in amino acid regions 117-165 and 195-211. Some of these amino acid substitutions coincided with the putative cytotoxic T-lymphocyte epitopes of both S and P proteins. CONCLUSIONS: A high frequency of HBV infection was seen using molecular methods in thalassemic patients. The frequency of infection was similar in vaccine responders and non-responders. A number of mutations were observed in the S gene, which could have implications for viral replication as well as virus-host cell interaction.

Adolescent↗
PubMed2002

HPTLC determination of diclofenac sodium from serum.

Diclofenac sodium is one of the potent Non Steroidal Anti-Inflammatory Drugs (NSAID) used in the treatment of inflammatory conditions. The present work deals with the estimation of diclofenac sodium from serum by a novel High Performance Thin Layer Chromatographic (HPTLC) method developed in our laboratory. Standard diclofenac sodium was spotted on Silica Gel 60 F(254) precoated plates, which were developed using the mobile phase toluene:acetone:glacial acetic acid (80:30:1,v/v/v). Densitometric analysis of diclofenac sodium was carried out at 280 nm with diclofenac being detected at an R(f) of 0.58. The method was subsequently developed to estimate diclofenac sodium from serum. Diclofenac sodium was extracted with ethyl acetate from serum samples, spotted on Silica Gel 60 F(254) plates and the plates were developed using the above mentioned mobile phase. The method was validated for selectivity, extraction efficiency, sensitivity, accuracy, and intra and inter-day reproducibility studies. The extraction efficiency was found to range from 76 to 80%. The Limit of Detection (LOD) and Limit of Quantification (LOQ) of diclofenac sodium in serum were found to be 90 and 120 ng, respectively. The calibration curve of diclofenac sodium in serum was found to be linear in the range of 200-800 ng. The mean values (+/-S.D.) of correlation coefficient, slope and intercept were found to be 0.9876 (+/-0.0105), 0.0228 (+/-0.0036) and 6.15 (+/-1.4), respectively. The mean percentage coefficient of variation for accuracy, intra-day and inter-day analysis at 200-800 ng of diclofenac sodium were found to be 3.2, 6.35 and 8.025, respectively. The proposed method is a simple and sensitive method with good precision and reproducibility for the estimation of diclofenac sodium form serum samples.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Effect of co-administration of piperine on pharmacokinetics of beta-lactam antibiotics in rats.

Co-administration of piperine, an alkaloid isolated from Piper nigrum L. enhanced bioavailability of beta lactam antibiotics, amoxycillin trihydrate and cefotaxime sodium significantly in rats. The improved bioavailability is reflected in various pharmacokinetic parameters viz. tmax, Cmax, t(1/2) and AUC, of these antibiotics. The increased bioavailability could be attributed to the effect of piperine on microsomal metabolising enzymes or enzymes system.

Alkaloids↗
PubMed2001

Pimprinine, an extracellular alkaloid produced by Streptomyces CDRIL-312: fermentation, isolation and pharmacological activity.

Pimprinine, an extracellular alkaloid has been isolated from the culture filtrate of Streptomyces CDRIL-312. Pimprinine was subsequently purified using silica gel column chromatography and also by preparatory thin layer chromatography. Some physicochemical properties, antimicrobial activities (in-vitro) and pharmacological activities of pimprinine were studied. Pimprinine showed promising anticonvulsant activity in both minimum and maximum electric seizure threshold test in mice. Its anticonvulsant activity is very much comparable to that of phenyl hydantion sodium. Pimprinine also inhibited effectively tremorine-induced tremors and analgesia in mice.

Animals↗
PubMed2001

Prevalence and natural history of subclinical hepatic encephalopathy in cirrhosis.

BACKGROUND AND AIMS: The natural history of subclinical hepatic encephalopathy (SHE) is unknown. The present study was conducted to study the prevalence and the natural history of SHE in patients with cirrhosis of the liver. METHODS: One hundred and sixty-five patients with cirrhosis of the liver were studied. A total of nine psychometric tests (trail making and Wechsler adult intelligence scale-performance (WAIS-P) tests) were administered. Subclinical hepatic encephalopathy was present if two or more psychometric tests were abnormal. Seventy-two patients (SHE 40, without SHE 32) also underwent serial psychometric testing on follow-up visits at 6-8 week intervals. RESULTS: Subclinical hepatic encephalopathy was present in 103 (62.4%) patients. The number and figure connection, block design and picture completion tests were the most useful in the detection of SHE. Severity of SHE, as assessed by the number of abnormal tests, was greater in patients with more severe liver disease. During follow up, SHE tended to persist or worsen in patients with poorer liver function. Although other clinical complications were similar in different groups, overt hepatic encephalopathy developed more commonly in those patients who had SHE at entry compared to those who did not (22.6 vs 5.6%, P = 0.044). Among the patients with SHE, the development of overt hepatic encephalopathy was more common in patients with Child's score of > 6 than with Child's score of <or= 6 (40 vs 5%, P = 0.019). CONCLUSIONS: We conclude that SHE is common in cirrhosis. The natural history of SHE is worse in patients with advanced cirrhosis and SHE probably predisposes the cirrhotic patient to overt hepatic encephalopathy.

Adult↗
PubMed2001

Two cases of ethylene dibromide poisoning.

Ethylene dibromide (EDB) is commonly available as a liquid pesticide for use as fumigant and preservative for storage of cereals and grains in India. Accidental or suicidal ingestion is often associated with often fatal delayed sudden hepatic or renal failure. We report 2 cases of EDB poisoning in humans.

Accidents↗
PubMed2001

Coeliac disease in Indian children: assessment of clinical, nutritional and pathologic characteristics.

Coeliac disease is an important cause of chronic diarrhoea, failure to thrive, and anaemia in children. Little information on the disease is available in India. This study was undertaken to determine the prevalence, clinical, anthropometric and histological profiles of coeliac disease in patients attending a tertiary referral centre in India. Coeliac disease was diagnosed in 42 (16.6%) of 246 children with chronic diarrhoea, failure to thrive, and anaemia. The mean ages at onset of symptoms and at diagnosis were 2.4 (range 0.5-10) years and 8.3 (range 3-14) years respectively, and a mean period of delay in diagnosis was 5.9 (range 1-13.5) years. Of the 42 cases, history of failure to thrive was observed in 38 (90%), chronic diarrhoea in 37 (88%), and anaemia in 6 cases. Short stature, under-nutrition, anaemia, oedema of feet, rickets, clubbing of fingers, features of vitamin A deficiency, and B-vitamin deficiency were found in 42, 26, 38, 9, 8, 6, 3, and 2 cases respectively. Onset of symptoms, such as, chronic diarrhoea and failure to thrive, was earlier in children with subtotal villous atrophy than in those with partial villous atrophy (mean +/- SD; 2.00 +/- 1.46 years vs 3.30 +/- 2.72 years; p < 0.05). Results of the study suggest that coeliac disease is not uncommon in Indian children. Coeliac disease should be considered in the differential diagnosis, particularly in children without any symptoms of diarrhoea.

Adolescent↗
PubMed2000

Duration of viraemia and faecal viral excretion in acute hepatitis E.

Data on duration of viral excretion and viraemia during hepatitis E virus (HEV) infection are limited. We tested serial stool and serum samples from 20 patients with acute hepatitis E for HEV RNA. Faecal excretion and viraemia in these patients were found to be short lived. In 19 patients, all samples obtained after biochemical resolution of hepatitis tested negative; in the remaining patient, HEV RNA was detected in the serum samples but not in stool after biochemical resolution. Long-term persistence of HEV in body fluids of infected individuals seems to be an unlikely reservoir for transmission of HEV.

Acute Disease↗
PubMed2000

In situ liposomal preparation containing amphotericin B: related toxicity and tissue disposition studies.

The purpose of this research was to develop a novel hydroalcoholic method for the preparation of liposome entrapping inclusion complex of amphotericin B (AmB) with a view to obtaining reduced toxicity and superior tissue distribution of AmB in vivo. The method involves initial preparation of AmB-hydroxypropyl-beta-cyclodextrin (AmB-HPBCD) intercalated proliposome which is subsequently converted into a liposome dispersion by single dilution method. The AmB-liposome (L-AmB) derived from proliposome exhibited a superior entrapment efficiency (94.8 +/- 0.7%) compared to liposomes prepared by employing a conventional solvent-based technique (89.7 +/- 2.9%). The dose that was lethal to 50% of subjects (LD50) (mg/kg) value of AmB contained in stabilized proliposome-based liposomes was 18.6 +/- 0.25, whereas that in conventional solvent-based liposomes was 7.8 +/- 0.25. Incorporation of AmB-HPBCD into hydroalcoholic liposomes enhanced antifungal activity in experimental aspergillosis in Balb/c mice in vivo: 80% survival was recorded after 7 days of therapy and the fungal load in lung was reduced. The results clearly demonstrate that preferential uptake of L-AmB entrapped inclusion complex (AmB-HPBCD) by the reticulo endothelial system correlated with diminished levels of AmB in infected (p > 0.05) and noninfected (p > 0.001) kidney after 24 hr compared to that observed with conventional solvent-based L-AmB. Therefore, proliposome-based liposome entrapping inclusion complex of AmB with HPBCD offered an improved therapeutic efficacy by lowering toxicity as well as by altering the tissue distribution pattern.

Amphotericin B↗
PubMed2000

Detection of circulating antigens by ELISA using penicillinase in sera of mice infected with Toxoplasma gondii.

An enzyme linked immunosorbent assay (ELISA) has been developed using penicillinase as an enzyme marker for the detection of Toxoplasma gondii antigens during the acute stage of infection in the sera of experimentally infected mice. Circulating antigens were detected as early as 2 days after the infection and all mice had antigenemia by fourth day. The developed ELISA test is sensitive, specific and reproducible.

Animals↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1999

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↗