Comparison between Rotary (Mtwo) and Manual (H-Files) Techniques for Instrumentation of Primary Teeth Root Canals.

BACKGROUND: The aim of the study is to compare instrumentation time between manual (H-files) and rotary (Mtwo) files along with patient and operator compliance in primary lower molars. MATERIALS AND METHODS: 30 primary teeth were selected and divided into two groups of 15 in each group instrumented with H-files and Mtwo files respectively. Time taken for instrumentation was calculated using stop watch. Patient and operator compliance was recorded through questionnaire. STATISTICAL ANALYSIS USED: Chi Square test was used to compare the distribution of teeth and number of canals. Independent Student t test was used to compare the mean time taken for instrumentation with both techniques in different canals and the mean overall time for instrumentation where P value is less than 0.001. Chi Square Goodness of Fit test was used to compare the patient's and operator's perspective regarding instrumentation techniques. RESULTS: The instrumentation time recorded with Mtwo files is less when compared with H-files. 66.7% children preferred H-files over Mtwo, 60% children reported pain while using H-files, 60% of children were scared on sight of Mtwo rotary system. Operator could manage 80% of children easily while using H-files, but it was found that operator ease of comfort was more with Mtwo rotary system. CONCLUSION: Time taken for instrumentation with Mtwo files was less as compared to H-files. It was convenient for the operator to manage the child using H-files but with the use of Mtwo files, marked reduction in the instrumentation time was appreciated.

Influence of diosmin pretreatment on the pharmacokinetics of chlorzoxazone in healthy male volunteers.

Chlorzoxazone, a centrally acting muscle relaxant, is a probe for cytochrome P450 2E1 (CYP2E1). The first part of the study consisted of oral administration of 250 mg of chlorzoxazone (Paraflex 250 tablet) alone to 12 healthy male volunteers. Blood samples were collected from the antecubital vein at intervals of 0, 0.5, 1, 2, 3, 4, 5, 6, 7, and 8 hours and urine voided during 0-4 and 4-8 hours was collected after the administration of chlorzoxazone. The second part of the study was conducted after a wash-out period of 7 days; 500 mg of diosmin (Venex 500) was administered daily for 9 days. On day 10, 250 mg of chlorzoxazone was administered. Blood and urine samples were obtained as mentioned above. Serum levels of chlorzoxazone were determined by HPLC. Pharmacokinetic parameters were determined based on non-compartmental model analysis using the computer program RAMKIN. Diosmin pretreatment significantly enhanced AUC, C(max) and t1/2 with a concomitant reduction in CL/f. The urinary excretion of 6-hydroxychlorzoxazone was decreased and unchanged chlorzoxazone was increased over 8 hours. Urinary metabolic ratios of 6-hydroxychlorazoxazone and chlorazoxazone were increased. After pretreatment with diosmin, overall excretion (0-8 h) of 6-hydroxychlorazoxazone and chlorazoxazone were decreased. Diosmin might have inhibited the microsomal CYP2E1-mediated hydroxylation of chlorazoxazone.

HIV sero-prevalance in general population of Warangal, A.P., South India.

HIV/AIDS pandemic has devastated many countries reversing national development; HIV was not seen in Asia and India till 1980. Now India has become epicenter of AIDS pandemic. During April 2002 to March 2003 the HIV+ ve pregnant women and their husbands were encouraged to enroll in the prospective study with informed consent. The study results consist of most of the females who are in the age group between 16-25 years who were affected by HIV High infection is observed in people with lower socio-economic and education background. High infection rate is observed in house wives (26.7%), laborers (23%) and agricultural workers (12.1%) followed by toddy tapers (5%), drivers (5.96%) and others (6 47%). HIV +ve subjects at Mother To Child Transmission (MTCT) centers are surprisingly clinically very healthy. No disease manifestation was noticed.

Cytochrome P450 3A: genetic polymorphisms and inter-ethnic differences.

Ethnicity is a demographic variable that plays an important role in interindividual variability of drug metabolism and response. The genetic variations of drug-metabolizing enzymes exhibiting interindividual differences of drug metabolism also show differences between populations. The reason for this is that the frequency of a polymorphism is found to differ between populations. The other reason is that different variants are seen in different populations. Most drugs are biotransformed in the body by cytochrome P450. The CYP3A isozymes are responsible for the metabolism of 50-60% of all currently prescribed drugs. Studies have shown that there is variability in CYP3A activity and also inter-ethnic differences in CYP3A-mediated drug metabolism. The purpose of this review is to focus on the genetic polymorphism and ethnic variations in CYP3A-mediated oxidative drug metabolism.

Design, synthesis and cytotoxic studies on the simplified oxy analog of eleutherobin.

A straight forward entry into nine membered B ring of eleutherobin as oxy analog and its cyctotoxic properties on HBL cell lines is described. Molecular modeling studies were carried out to ascertain the binding of the model compound to the active site of beta-tubulin.

Selective activation of anthracycline prodrugs for use in conjunction with ADEPT.

A major limitation in the chemotherapy of cancer results from the lack of tumor specificity displayed by most anticancer drugs. In this regard, a great deal of research has been focused on the development of new chemotherapeutic agents that are able to effectively exploit the differences between neoplastic and normal tissues. Several cancerous tissues and tumors are rich in certain lysosomal enzymes as compared with those found in the normal tissues. Thus, a prodrug can be designed to selectively target such tumor cells where it can be activated to antineoplastic agent by tumor-associated antigen-targeted monoclonal antibody-enzyme conjugate (antibody directed enzyme prodrug therapy strategy) or by the action of an enzyme present at high levels in tumor tissues (prodrug monotherapy strategy). This approach protects the normal cells from the cytotoxic effects of the drug. In the last few years, a number of new MAb-based reagents has been clinically approved (Rituxan, Herceptin and Panorex), and several others are now in advanced clinical trials. This review focuses on the design of several different enzyme/prodrug combinations with an emphasis on mechanistic insight and clinical activity.

HPLC determination of valproic acid in human serum.

A HPLC method for the determination of valproic acid (VA) in human serum using diazepam as internal standard (I.S.) is described. The eluates were separated with a C18 250 x 4.6 mm internal diameter reversed phase column maintained at a temperature of 50 degrees C. A mobile phase consisting of acetonitrile and 0.05 M phosphate buffer (pH 3.0) 45:55 v/v was used at a flow rate of 1.2 ml/min. Wavelength was switched from 360 nm to 210 nm during valproic acid retention. The method was linear over a concentration range of 20 to 160 microg/ml for valproic acid. Recovery was greater than 94% over a concentration range of 20 to 120 microg/ml and the limit of quantitation was 1 microg/ml. The intra day and inter day relative standard deviation (R.S.D.) measured at 20, 60, 80 and 120 microg/ml ranged from 1.46 to 5.34% and 0.83 to 5.03% respectively. The method is simple, rapid, accurate and sensitive and it was used for Therapeutic Drug Monitoring (TDM) in Indian epileptic patient population. The results obtained with this method correlated well with clinical practice.

Oxidative stress and anti-oxidant status in leprosy patients.

Severe oxidative stress has been reported in leprosy patients because of malnutrition and poor immunity. The purpose of this study was to investigate the serum lipid peroxidation products, serum LDH and important free radical scavenging enzymes, i.e. superoxide dismutase (SOD), and catalase and anti-oxidant glutathione levels and total anti-oxidant status, in different types of leprosy patients. The subjects for this study were normal human volunteers (NHVs, n=14), paucibacillary leprosy patients (PB, n=18), untreated MB patients (MB1, n=18), MB patients under treatment (MB2, n=19), and MB patients released from treatment (RFT) (MB3, n=28). The levels of lipid peroxidation product, malondialdehyde (MDA), and LDH increased significantly (p<0.001) in MB (MB1, MB2, MB3) patients, and both gradually decreased with clinical improvement following MDT. The levels of SOD, catalase and glutathione, and the total anti-oxidant status decreased significantly in MB (MB1, MB2, MB3) patients (p<0.001), in comparison with NHVs. They gradually increased with clinical improvement with MDT. There was no significant variation of these parameters in PB leprosy patients in comparison with healthy volunteers. High free radical activity and low anti-oxidant levels observed in MB (MB1, MB2, MB3) leprosy patients indicate that there is an oxidative stress in MB cases, irrespective of the treatment status and suggest a suitable anti-oxidant therapy to prevent possible tissue injury.

Validated HPLC method for the determination of tinidazole in human serum and its application in a clinical pharmacokinetic study.

A high performance liquid chromatographic (HPLC) method for the determination of tinidazole in human serum using metronidazole as internal standard (IS) is described. Protein precipitation is used for the preparation of sample. Mobile phase consisting of 0.002 M phosphate buffer, methanol and acetonitrile mixture (85:7.5:7.5/v/v/v) was used at a flow rate of 1 ml/min on a C18 column. The eluate was monitored using an UV/Vis detector set at 320 nm. Ratio of peak area of analyte to IS was used for quantification of serum samples. The absolute recovery was greater than 95% over a concentration range of 0.5 to 30 micrograms/ml and the limit of quantitation was 0.05 microgram/ml. The intra-day relative standard deviation (RSD) measured at 0.5, 5, 15 and 30 micrograms/ml ranged from 0.36 to 6.14%. The inter-day RSD ranged from 1.14 to 4.21%. The method is simple, sensitive and has been successfully used in a pharmacokinetic study conducted in healthy human volunteers.

Validated HPLC method for determination of chlorzoxazone in human serum and its application in a clinical pharmacokinetic study.

A high performance liquid chromatographic (HPLC) method for the determination of chloroxazone in human serum using phenacetin as internal standard (IS) is described. Protein precipitation is used for preparation of the sample. A mobile phase consisting of acetonitrile and 0.5% acetic acid in water mixture (40:60 v/v) was used at a flow rate of 1 ml/min on a C18 column. The eluate was monitored using an UV/VIS detector set at 287 nm. Ratio of peak area of analyte to IS was used for quantification of serum samples. The absolute recovery was greater than 96% over a concentration range of 1 to 100 micrograms/ml and the limit of quantitation was 0.05 microgram/ml. The intra-day relative standard deviation (RSD) measured at 1, 10, 50, and 100 micrograms/ml ranged from 0.9 to 5.1%. The inter-day RSD ranged from 0.6 to 3.0%. The method is simple, sensitive and has been successfully used in pharmacokinetic study conducted in healthy human volunteers.

Assessment of antioxidant activity of some antileprotic drugs.

DPPH (alpha,alpha-diphenyl-beta-picryl hydrazyl) (CAS 217-591-8), a stable free radical can be used to determine the antioxidant activity (AOA) of some drugs. In the present study the DPPH method was used for the first time to test AOA of dapsone (CAS 80-08-0), clofazimine (CAS 2030-63-9) and rifampicin (CAS 13282-42-1) in vitro and deproteinated blood method. Ascorbic acid (CAS 50-81-7) was used as a control in the study, which showed concentration-dependent antioxidant activity. Rifampicin showed a per se effect but it showed concentration dependent decrease in the DPPH absorbance. Ascorbic acid, dapsone and rifampicin showed DPPH scavenging activity both in vitro and deproteinated blood method. Clofazimine did not have any influence on DPPH. This method may be extended to different drugs for testing their AOA in biological fluids.

Influence of rice bran oil on serum lipid peroxides and lipids in human subjects.

To study the effect of rice bran oil (RBO) on serum lipids and lipid peroxides in human volunteers. Nine healthy volunteers, aged between 42 to 57 years were given 75 ml of RBO thrice daily as the cooking medium with break fast, lunch and dinner for a period of 50 days. At the beginning and at the end of 50 days, 5 ml of blood were drawn from an ante cubital vein. Serum lipids and lipid peroxides levels were estimated from the blood sample. There was a significant decrease in the levels of lipid peroxides, triglycerides, LDL, VLDL, and total cholesterol in human volunteers who switched over to RBO. RBO has evidently antioxidant and antilipidemic activities in human subjects.

Does pH 6 beta-galactosidase activity indicate cell senescence?

Apparently two forms of beta-galactosidase (beta-GAL) in cells or tissue sections can be detected by enzyme histochemical staining (X-GAL). Using a sensitive and specific HPLC method we have determined the pH dependent activity of beta-GAL in cell lines of lung carcinoma (A549), colon carcinoma (Caco2-TC7), promyelocytic leukemia (HL60), hepatoma (HepG2) and human liver homogenates. The HPLC method has been validated and the influence of pH and substrate concentration was studied. There was a good linear correlation between HPLC and quantitative enzyme histochemistry (pH 4.5: r = 0.985; pH 6.0: r = 0.967). Both, pH 4.5 beta-GAL and pH 6 beta-GAL could be demonstrated in all biological material tested and pH 6 beta-GAL activity was always lower (25-50%) than pH 4.5 activity. In Caco2-TC7 cells both activities increased by a factor of 10 from day 3 to day 17 after seeding. In addition, since the beta-GAL activity decreased with increase in pH both in human liver homogenates (independent of the age of the donor) as well as in tumor cell lysates in a similar fashion we believe that the activity at pH 6 can hardly be considered as an exclusive 'senescence marker'. In addition, the more sensitive HPLC method could demonstrate activity in cells that showed negative reaction with X-GAL.

Pro- and anti-oxidant effects of some antileprotic drugs in vitro and their influence on super oxide dismutase activity.

The effect of ofloxacin (CAS 82419-36-1), dapsone (CAS 80-08-0), rifampicin (CAS 13282-46-1) and clofazimine (CAS 2030-63-9) on the generation of superoxide anions was studied in vitro. The drugs were incubated with a superoxide generating system (photochemical reaction between riboflavin and dianisidine). The change in optical density was measured. The optical density was increased with dapsone and ofloxacin and decreased in presence of clofazimine and rifampicin. This result indicates that ofloxacin and dapsone have an antioxidant property, whereas clofazimine and rifampicin behave as pro-oxidants.

Transdermal delivery of isosorbide 5-mononitrate from a new membrane reservoir and matrix-type patches.

Isosorbide 5-mononitrate (5-ISMN) has a direct relaxing effect on vascular smooth muscle. In the present study we developed matrix and reservoir-type transdermal patches of 5-ISMN. We investigated the usefulness of a new film-forming material isolated from the roots of Salacia macrosperma to serve as rate-controlling membrane for the reservoir-type patches. Matrix-type patches were formulated using polyvinyl chloride. Permeation studies through rat skin were conducted on both types of patches using Teflon cells. The mean +/- SD flux values from the matrix- and reservoir-type patches were 99.55 +/- 22.89 and 31.82 +/- 8.31 micrograms/cm2.hr, respectively.

Probenecid affects the pharmacokinetics of ofloxacin in healthy volunteers.

OBJECTIVE: The aim of this randomised, double-blind, crossover study was to evaluate the effect of single-dose probenecid on the pharmacokinetics of ofloxacin in eight healthy male volunteers. METHODS: After an overnight fast, and according to a randomised sequence, each volunteer received either single oral ofloxacin 200mg (Hoechst Marion Roussel Ltd., Mumbai, India) or both ofloxacin (1 x 200mg) and probenecid (1 x 500mg) [Geno Pharmaceutical Ltd., Mumbai, India]. Blood samples were collected at regular intervals until 24 hours. Serum concentration versus time profiles for ofloxacin were generated and pharmacokinetic parameters were calculated by noncompartmental model analysis. RESULTS: Elimination half-life, mean residence time and area under the curve were significantly increased (4.86 vs 5.26h; 7.23 vs 7.95h; 10.28 vs 11.9 mg/L . h) [p < 0.01], whereas the total clearance was decreased (19.66 vs 16.95 L/h) [p < 0.01] in the presence of probenecid. Other pharmacokinetic parameters were not significantly affected by coadministration of probenecid. CONCLUSION: Concomitant administration of probenecid with ofloxacin may result in a decreased elimination half-life and consequently increased bioavailability of ofloxacin. Probenecid may be co-prescribed with ofloxacin; patients taking this combination should be closely monitored and dosage reduction should be considered if warranted in high-risk patients.

Characterization of leprosy based on the nasal lipid profile.

While extracting the M. leprae from the nasal flushings of leprosy patients it was found that these organisms were trapped in the waxy layer, between the aqueous and the chloroform layers. Thin layer chromotography (TLC) analysis of this layer, using chloroform-methanol-water system, revealed different spots when sprayed with acid alcohol and heated at 160 degrees C. The TLC profile of lipids of lepromatous and borderline (MB according to the WHO terminology) leprosy patients was distinctly different from that of tuberculoid leprosy patients and normal human volunteers. A simple, economical and fast procedure to characterize patients belonging to different spectra has been developed.

Characterization of clofazimine metabolites in humans by HPLC-electrospray mass spectrometry.

Clofazimine (CAS 2030-63-9) is an important drug used in the treatment of leprosy. Its important metabolites are investigated by thin layer chromatography (TLC), HPLC (diode array) and HPLC-electrospray mass spectrometry. The resulting analytical data, extraction, isolation and characterization methods are presented. Their applicability is described for human urine analysis.

Disposition of rifampicin following intranasal and oral administration.

Leprosy is transmitted by dissemination of M.leprae which are lodged in the nose of the patients suffering from multibacillary (MB) type of the disease. Rifampicin, a potent bactericidal antileprotic drug is given orally to the patients with a view to make the infective cases non-infective. Earlier work by us has shown that intranasal administration of rifampicin helps in reducing the M.leprae load in the nose much faster than after conventional oral administration. In the present study, rifampicin concentrations in plasma/urine/nasal wash of healthy volunteers following oral and intranasal administration were determined. Following intranasal administration, rifampicin was not detectable in plasma and high concentrations were measured in the nasal wash. Following oral administration, rifampicin was not detectable in the nasal wash indicating that enough antibiotic levels are not available for clearing M.leprae from nose.