Structure, localization and histone binding properties of nuclear-associated nucleosome assembly protein from Plasmodium falciparum

BACKGROUND

Nucleosome assembly proteins (NAPs) are histone chaperones that are crucial for the shuttling and incorporation of histones into nucleosomes. NAPs participate in the assembly and disassembly of nucleosomes thus contributing to chromatin structure organization. The human malaria parasite Plasmodium falciparum contains two nucleosome assembly proteins termed PfNapL and PfNapS.

METHODS

Three-dimensional crystal structure of PfNapS has been determined and analysed. Gene knockout and localization studies were also performed on PfNapS using transfection studies. Fluorescence spectroscopy was performed to identify histone-binding sites on PfNapS. Extensive sequence and structural comparisons were done with the crystal structures available for NAP/SET family of proteins.

RESULTS

Crystal structure of PfNapS shares structural similarity with previous structures from NAP/SET family. Failed attempts to knock-out the gene for PfNapS from malaria parasite suggest essentiality in the parasite. GFP-fused PfNapS fusion protein targeting indicates cellular localization of PfNapS in the parasite nucleus. Fluorescence spectroscopy data suggest that PfNapS interacts with core histones (tetramer, octamer, H3, H4, H2A and H2B) at a different site from its interaction with linker histone H1. This analysis illustrates two regions on the PfNapS dimer as the possible sites for histone recognition.

CONCLUSIONS

This work presents a thorough analysis of the structural, functional and regulatory attributes of PfNapS from P. falciparum with respect to previously studied histone chaperones.

Cystojejunostomy for non-parasitic hepatic cyst with biliary communication

Non-parasitic hepatic cysts containing bile are rare entities and pose a challenge in surgical management as they cannot be managed by simple de-roofing. The biliary communication to the cyst cavity should either be closed meticulously, or these cysts should be managed by an internal drainage procedure such as cystoenterostomy. We report a 17-year-old Indian girl, in which such a cyst was treated by cystojejunostomy.

M-01ZH09, an oral live attenuated Salmonella enterica serovar Typhi vaccine for the prevention of typhoid fever

Typhoid fever remains a major health problem globally, particularly in the developing world. The increased emergence of several multidrug-resistant strains of Salmonella enterica serovar Typhi has made the management of the disease increasingly difficult. Although vaccines against typhoid fever are available, improvements are desired in dosage, immunogenicity and tolerability. Emergent BioSolutions Inc is developing M-01ZH09, a single-dose oral vaccine against typhoid fever based on an attenuated strain of S enterica serovar Typhi. Several clinical trials have been completed for the vaccine, including large phase II trials in the US and Vietnam. Additionally, a phase IIc clinical trial was ongoing in India at the time of publication. The available data suggest that M-01ZH09 is well tolerated in clinical trials, and is highly immunogenic, provoking broad immune responses. Because M-01ZH09 involves administration as a single oral dose, the vaccine has the potential to be used in a mass immunization program.

CYP11B2 gene haplotypes independently and in concurrence with aldosterone and aldosterone to renin ratio increase the risk of hypertension

OBJECTIVES

Aldosterone synthase produces aldosterone, which regulates electrolytes and thereby blood pressure. Polymorphisms in aldosterone-synthase gene (CYP11B2) may associate with heterogeneous aldosterone production and hypertension. Hence, we investigated -344T/C, Iw/Ic polymorphisms of CYP11B2, plasma renin activity (PRA) and aldosterone concentration (PAC).

DESIGN AND METHODS

Consecutive ethnically-matched 450 hypertensive patients and 360 controls were screened by PCR-RFLP for genotypes and haplotypes; PRA and PAC were measured.

RESULTS

The Iw/Ic polymorphism distribution differed significantly between the two groups (LRT chi(2)=15.8, df=2, P=0.000). The mutant allele-Ic and genotype-Ic/Ic were overrepresented in patients (35% versus 27% and 13% versus 7%). Overrepresentation of T-Ic haplotype in patients was identified as risk haplotype (P=0.000). Patients had significantly higher PAC and aldosterone-to-renin ratio (ARR; P=0.000), which was Ic-allele dependent.

CONCLUSIONS

The haplotype T-Ic associated with hypertension susceptibility. Correlation between Ic-allele and raised ARR likely serve in hypertension management.

Polyelectrolyte coated multilayered liposomes (nanocapsules) for the treatment of Helicobacter pylori infection

Helicobacter pylori infection is one of the major causes of gastric cancers. A number of systems have already been reported, but 100% eradication has never been achieved. The present invention designs a gastro-retentive drug delivery system incorporated with amoxicillin and metronidazole, specifically suited for the eradication of Helicobacter pylori infections due to its mucoadhesiveness in the presence of polyelectrolyte polymers. The system possesses the advantages of both vesicular and particulate carriers, and it was prepared by alternative coating of polyanion (poly(acrylic acid), PAA) and polycation (poly(allylamine hydrochloride), PAH) using liposomes as the core. Compared with the conventional liposomes, the polyelectrolyte based multilayered system (nanocapsules) gave prolonged drug release in simulated gastric fluid, which is well suited for drug delivery against H. pylori infection in the stomach. In vitro growth inhibition study, agglutination assay, and in situ adherence assay in cultured H. pylori suggested the successful in vitro activity and binding propensity of the system. In vivo bacterial clearance study carried out in a H. pylori infected mouse model finally confirmed the success of the developed novel nanocapsule system. Thus, the newly developed composite nanocapsules along with the use of combination therapy proved to have commendable potential in Helicobacter pylori eradication as compared to already existing conventional and novel drug delivery systems.

Emergence of Virulence to Sr25 of Puccinia graminis f. sp. tritici on Wheat in India

Stem (black) rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks. & Henn., is one of the most destructive diseases of wheat. It could be controlled through introgression of race-specific resistance genes. However, such kind of resistance is mostly short lived due to emergence of new virulences. For example, resistance genes Sr11, Sr24, Sr30, and Sr31 are no longer effective (2,4). Detection of new virulences has remained vital in the evaluation and identification of new sources of resistance. We report here the detection of virulence to Sr25, a gene from Thinopyrum elongatum (4), which had been effective or partially effective against stem rust worldwide, including race Ug99 (TTKSK) (4). A stem rust isolate collected in 2006 from Karnataka (southern India) produced susceptible reactions (infection type [IT] 3+ to 4) on the primary leaves of differential genotype 'Agatha' carrying Sr25 and susceptible check 'Agra Local' at 22 ± 2°C. To verify virulence to Sr25, single-pustule isolates from this sample were inoculated onto seedlings of 'Agrus', 'Agatha', 'RL6040' ('Thatcher' + Sr25), 'Superseri#1', 'Wheatear', and 'Morocco' + Sr25 (obtained from CIMMYT), which all carry Sr25. All these accessions were found susceptible (IT 3+ to 4) to this isolate, except Wheatear which expressed resistance (IT ;1), indicating the presence of additional gene(s). These genotypes are resistant (ITs ;1 to 2+) to Sr25-avirulent pathotypes. The new pathotype is avirulent to Sr11, 13, 14, 21, 22, 23, 24, 26, 27, 29, 31, 32, 33, 35, 37, 38, 39, 40, 43, and Tmp and virulent to Sr5, 6, 7a, 7b, 8a, 9a, 9b, 9d, 9e, 9f, 9g, 10, 12, 15, 16, 17, 18, 19, 20, 25, 28, 30, 34, 36, 42, Wld-1, and Gt at 22 ± 2°C. This pathotype has been designated as 58G13-3 and PKTSC according to the Indian nomenclature (1) and the North American system (3), respectively. It represents race 40 based on Stakman's differentials. It may have arisen from race 40 through mutation. The type culture of the pathotype has been added to the culture collection at Flowerdale, Shimla. Interestingly, 'Festiguay' (Sr30) was found resistant to this pathotype, indicating the presence of additional gene(s), whereas 'Webster' (Sr30) was susceptible. Adult plants of Agrus, Agatha, RL6040, Superseri#1, and Morocco+Sr25 also were susceptible, producing 20S to 60S responses. Sr25-avirulent pathotype 62G29 produced a TR (flecking in traces) response on these lines except Morocco + Sr25 that showed 20 to 40MR (moderately resistant) responses. In the same study however, adult plants of Thatcher showed a resistant reaction (10R to MR) at low (16 ± 2°C) and susceptible (20S) at high (22 ± 2°C) temperatures. Agatha and RL6040, having Thatcher as one of the parents, had similar responses. The detection of Sr25 virulence is significant since Sr25 is an important gene to be targeted for breeding wheat cultivars resistant to Ug99. We should use either adult plant resistance and/or pyramiding two or more genes for seedling resistance to enhance the field life of wheat cultivars. References: (1) P. Bahadur et al. Proc. Indian Acad. Sci. 95:29, 1985. (2) S. C. Bhardwaj et al. J. Wheat Res. 1:51, 2007. (3) Y. Jin et al. Plant Dis. 92:923, 2008. (4) R. P. Singh et al. CAB Rev. No. 054:1, 2006.

Molecular variants of HPV-16 associated with cervical cancer in Indian population

Human papilloma virus is a causative factor in the etiology of cervical cancer with HPV16 being the most prevalent genotype associated with it. Intratype variations in oncogenic E6/E7 and capsid L1 proteins of HPV 16 besides being of phylogenetic importance, are associated with risk of viral persistence and progression. The objective of this multicentric study was to identify HPV-16 E6, E7 and L1 variants prevalent in India and their possible biological effects. Squamous cell cervical cancer biopsies were collected from 6 centres in India and examined for the presence of HPV 16. Variants of HPV-16 were characterized by full length sequence analysis of L1, E6 and E7 genes in 412 samples. Similar distribution of the variants was seen from the different centres/regions, with the European variant E350G being the most prevalent (58%), followed by American Asian variant (11.4%). Fifty six changes were seen in E6 region, 31 being nonsynonymous. The most frequent being L83V (72.3%), Q14H (13.1%) and H78Y (12.1%). Twenty-nine alterations were seen in E7 region, with 12 being nonsynonymous. The most frequent being F57V (9%). L1 region showed 204 changes, of which 67 were nonsynonymous. The most frequent being 448insS (100%), and 465delD (100%), H228D (94%), T292A (85%). The identified variants some new and some already reported can disrupt pentamer formation, transcriptional regulation of the virus, L1 protein interface interaction, B and T cell epitopes, p53 degradation, and thus their distribution is important for development of HPV diagnostics, vaccine, and for therapeutic purpose.

Multi-locus interactions of vascular homeostasis genes in essential hypertension: a gender-based study

BACKGROUND

Studies on genes of endothelial and vascular homeostasis are inadequate in females.

METHODS

We investigated the role of 7 variants of ACE, AGT and NOS3 and their correlation with NO(x) levels and ACE activity in hypertension susceptibility in 910 case-controls of both genders.

RESULTS

Prevalence of alleles D of ACE I/D; -6A of AGT -6G/A; -786C, 894T and 4a of NOS3 -786T/C, 894G/T and 4b/4a polymorphisms was observed in patients (P< or =0.05). The 3 genotypes-combinations containing 6+5 wild-type alleles of AGT and NOS3 were significantly less prevalent in patients (P< or =0.0003). The haplotypes 235T/174T/-6A of AGT (P=4E-3) and -786T/894G/4a and -786C/894G/4a of NOS3 (P=2E-3, P=0.011, respectively) were significantly more prevalent in patients. The AGT and NOS3 findings were similar in males. Genotypes-combinations with 6+5 wild-type alleles of AGT correlated with higher NO(x) levels (P=0.03). The NOS3 genotypes-combinations having 6 and 6+5 wild-type alleles correlated with decreased ACE activity (P=0.025, P=0.0015, respectively) and increased NO(x) levels (P=0.001, P=0.0001, respectively) in patients. In gene-gene interactions, ACE D allele associated with < or =4 wild-type alleles containing genotypes-combinations of AGT and NOS3 in patients (P< or =0.04).

CONCLUSION

Within gene and between genes interactions of variants influence ACE activity and NO(x) levels and associate with EH.

Crystal structure of malaria parasite nucleosome assembly protein: distinct modes of protein localization and histone recognition

Nucleosome assembly proteins (NAPs) are histone chaperones that are essential for the transfer and incorporation of histones into nucleosomes. NAPs participate in assembly and disassembly of nucleosomes and in chromatin structure organization. Human malaria parasite Plasmodium falciparum contains two nucleosome assembly proteins termed PfNapL and PfNapS. To gain structural insights into the mechanism of NAPs, we have determined and analyzed the crystal structure of PfNapL at 2.3 A resolution. PfNapL, an ortholog of eukaryotic NAPs, is dimeric in nature and adopts a characteristic fold seen previously for yeast NAP-1 and Vps75 and for human SET/TAF-1b (beta)/INHAT. The PfNapL monomer is comprised of domain I, containing a dimerization alpha-helix, and a domain II, composed of alpha-helices and a beta-subdomain. Structural comparisons reveal that the "accessory domain," which is inserted between the domain I and domain II in yeast NAP-1 and other eukaryotic NAPs, is surprisingly absent in PfNapL. Expression of green fluorescent protein-tagged PfNapL confirmed its exclusive localization to the parasite cytoplasm. Attempts to disrupt the PfNapL gene were not successful, indicating its essential role for the malaria parasite. A detailed analysis of PfNapL structure suggests unique histone binding properties. The crucial structural differences observed between parasite and yeast NAPs shed light on possible new modes of histone recognition by nucleosome assembly proteins.

Inflammatory response to isocyanates and onset of genomic instability in cultured human lung fibroblasts

Lungs comprise the primary organ exposed to environmental toxic chemicals, resulting in diverse respiratory ailments and other disorders, including carcinogenesis. Carcinogenesis is a multi-stage phenomenon, which involves a series of genetic alterations that begin with genomic instability provoked by certain factors such as inflammation and DNA damage and end with the development of cancer. Isocyanates such as methyl isocyanate are the chief metabolic intermediates in many industrial settings with diverse applications; exposure to them can lead to severe hypersensitive, mutagenic and genotoxic alterations. We examined the molecular mechanisms underlying isocyanate-mediated inflammatory responses and their probable role in the onset of genomic instability in cultured IMR-90 human lung fibroblasts. The isocyanates induced inflammation, resulting in extensive DNA damage, evidenced by increases in ATM, ATR, gammaH2AX, and p53 expression levels. The apoptotic index also increased. Chromosomal anomalies in treated cells included over-expression of centrosome protein and variable amplification of inter-simple sequence repeats, further demonstrating isocyanate-induced genomic instability. This information could be useful in the design of new approaches for risk assessment of potential industrial disasters.

Nitrate removal using Brevundimonas diminuta MTCC 8486 from ground water

Brevundimonas diminuta MTCC 8486, isolated from marine soil of coastal area of Trivandrum, Kerala, was used for biological removal of nitrate from ground water collected from Kar village of Pali district, Rajasthan. The organism was found to be resistance for nitrate up to 10,000 mg L(-1). The optimum growth conditions for biological removal of nitrate were established in batch culture. The effect of carbon sources on nitrate removal was investigated using mineral salt medium (MSM) containing 500 mg L(-1) of nitrate to select the most effective carbon source. Among glucose and starch as carbon source, glucose at 1% concentration increased the growth (182+/-8.24 x 10(4) CFU mL(-1)) and induced maximum nitrate reduction (86.4%) at 72 h. The ground water collected from Kar village, Pali district of Rajasthan containing 460+/-5.92 mg L(-1) of nitrate was subjected to three different treatment processes in pilot scale (T1 to T3). Higher removal of nitrate was observed in T2 process (88%) supplemented with 1% glucose. The system was scaled up to 10 L pilot scale treatment plant. At 72 h the nitrate removal was observed to be 95% in pilot scale plant. The residual nitrate level (23+/-0.41 mg L(-1)) in pilot scale treatment process was found to be below the permissible limit of WHO.

Anti-Salmonella activity of Terminalia belerica: in vitro and in vivo studies

To search for an herbal remedy for protection against and treatment for typhoid fever, a number of plants were screened. Anti-Salmonella activity of Terminalia belerica, an ingredient of Ayurvedic preparation 'triphala' used for treatment of digestive and liver disorders, has been reported. Fruits of T. belerica were extracted with petroleum ether, chloroform, acetone, alcohol and water and efficacy of extracts against Salmonella typhi and Salmonella typhimurium was evaluated. Alcoholic and water extracts of T. belerica showed significant anti-Salmonella activity and MIC was 12.5 mg/ml against S. typhimurium. Aqueous extracts of Picrohiza kurroa and Vitits vinefera also showed low anti-Salmonella activity where as aqueous extracts of Asparagus racemosus and Zingiber officinale showed no anti-Salmonella activity. Extracts of T. belerica, Picrohiza kurroa and Vitits vinefera with other solvents such as chloroform and petroleum ether showed insignificant activity. Results showed that aqueous extract of T. belerica was bactericidal at high concentrations where as low concentrations showed bacteriostatic property. In vitro cellular toxicity studies showed no cyto-toxicity associated with T. belerica extracts. Pretreatment of mice with aqueous extract of T. belerica conferred protection against experimental Salmonellosis and 100% survival of animals has been reported when challenged with lethal doses of S. typhimurium.

Development and Characterization of Mucoadhesive Microspheres Bearing Salbutamol for Nasal Delivery

Mucoadhesive drug delivery systems are those that provide intimate contact of the drug with the mucosa for an extended period of time. In our present work, mucoadhesive chitosan microspheres were prepared by emulsion solvent method. Formulations were characterized for various physicochemical attributes, shape, surface morphology, size, and size distribution, drug payload, swelling ability, and mucoadhesion. The effect of drug, citric acid, and permeation enhancer concentration on the physicochemical properties was studied. Crosslinked chitosan microspheres showed very good mucoadhesion, which was decreased on increasing the drug concentration and citric acid concentration, and slightly improved upon incorporation of permeation enhancer. The in vitro drug release and in vitro drug permeability through mucous membrane were performed, and slow release/permeation was noted with chitosan citrate complexed microspheres compared with noncomplexed chitosan microspheres. The in vivo performance of mucoadhesive microspheres formulations showed prolonged and controlled release of salbutamol as compared with oral administration of conventional dosage form.

Design and Development of Multiparticulate System for Targeted Drug Delivery to Colon

A multiparticulate system combining pH-sensitive property and specific biodegradability for colon-targeted delivery of metronidazole has been investigated. Cross-linked chitosan microspheres were prepared from an emulsion system using liquid paraffin as the external phase and solution of chitosan in acetic acid as the disperse phase. The multiparticulate system was prepared by coating cross-linked chitosan microspheres exploiting Eudragit L-100 and S-100 as pH-sensitive polymers. Morphology and surface characteristics of the formulations were determined by scanning electron microscopy. Particle size of the chitosan microspheres was determined by optical microscopy while that of coated microspheres was determined by particle size analyzer. In vitro drug-release studies were performed in conditions simulating stomach-to-colon transit in presence and absence of rat caecal contents. The size of the microspheres was small and they were efficiently microencapsulated within Eudragit microspheres, forming a multireservoir system. By coating the microspheres with Eudragit pH-dependant release profiles were obtained. No release was observed at acidic pH; however, when it reached the pH where Eudragit starts solublizing there was continuous release of drug from the formulation. Further, the release of drug was found to be higher in the presence of rat caecal contents, indicating the susceptibility of chitosan matrix to colonic enzymes released from rat caecal contents.

Polysaccharides for Colon Targeted Drug Delivery

Colon targeted drug delivery has the potential to deliver bioactive agents for the treatment of a variety of colonic diseases and to deliver proteins and peptides to the colon for their systemic absorption. Various strategies, currently available to target the release of drugs to colon, include formation of prodrug, coating of pH-sensitive polymers, use of colon-specific biodegradable polymers, timed released systems, osmotic systems, and pressure controlled drug delivery systems. Among the different approaches to achieve targeted drug release to the colon, the use of polymers especially biodegradable by colonic bacteria holds great promise. Polysaccharidases are bacterial enzymes that are available in sufficient quantity to be exploited in colon targeting of drugs. Based on this approach, various polysaccharides have been investigated for colon-specific drug release. These polysaccharides include pectin, guar gum, amylose, inulin, dextran, chitosan, and chondroitin sulphate. This family of natural polymers has an appeal to drug delivery as it is comprised of polymers with a large number of derivatizable groups, a wide range of molecular weights, varying chemical compositions, and, for the most part, low toxicity and biodegradability yet high stability. The most favorable property of these materials is their approval as pharmaceutical excipients.

Development of Matrix-Membrane Transdermal Drug Delivery System for Atenolol

A polymer matrix system for transdermal delivery of Atenolol was developed for its prolonged and controlled release systemic availability. To achieve the desired and controlled release rate, different combinations of Eudragit RL with polyvinyl pyrrolidone and polyethylene glycol 4000 were used in the preparations of polymeric matrix system. These preparations were evaluated for in vitro release and permeation of the drug across pig skin. The desired systems exhibited linear relationship between drug release (Q) versus ne0.8(hr0.8). The product exhibiting required skin permeation 64 mcg/h/cm2 to achieve an effective plasma concentration was selected for the in vivo performance evaluation. The drug plasma profile was compared with the plasma profile obtained following the administration of a conventional oral dose of Atenolol. The study revealed that the designed polymeric matrix transdermal drug delivery system of Atenolol could be successful with improved performance.

Methotrexate bearing calcium pectinate microspheres: a platform to achieve colon-specific drug release

In the present work calcium pectinate (Ca-pectinate) microspheres were prepared to deliver methotrexate in the environment of colon. Calcium pectinate microspheres were prepared by modified emulsification method using calcium chloride as cross linker. All the formulations were evaluated for various physicochemical parameters. Particle size of the microspheres was determined using laser diffraction particle size analyzer. Encapsulation efficiency was determined by digesting with enzyme pectinase for 24 hours and swellability by equilibrium swelling in simulated gastrointestinal fluid. The in vitro drug release studies were performed in simulated gastric fluid for 2 hours and simulated intestinal fluid for 3 hours. In vitro release rate studies were also carried out in simulated colonic fluid in presence of rat caecal contents. Moreover, release rate studies were also carried out after enzyme induction by treating the rats with 1 ml of 1% w/v aqueous dispersion of pectin for 7 days. Mean particle size of the microspheres was found to be in the range of 20.82+/-1.34 to 32.26+/-1.59 microm whereas the entrapment efficiency varied from 52.28+/-0.32 to 74.01+/-3.32%. The in vitro drug release studies in simulated gastric fluid and simulated intestinal fluid showed that only 8.15+/-0.49% drug was released in 5 hours whereas most of the loaded drug was released in simulated colonic fluid containing pectinase. In vitro release rate study showed release of 69.94+/-3.46% of drug in presence of 3% rat caecal contents, which was further increased to 94.43+/-4.48% when enzyme induction was carried out for 7 days. Thus, it is concluded that calcium pectinate microspheres can be used to effectively localize the release of drug in the physiological environment of colon.

Transdermal atenolol releasing system: An approach towards its development

A polymer matrix system for transdermal delivery of atenolol was developed for its prolonged and controlled release using different ratios of ethylcellulose and hydroxypropyl methylcellulose. These polymeric matrix films were characterized for thickness, tensile strength, moisture content and drug content. They were also studied for in vitro drug release and in vitro drug skin permeation. The drug release from the films was found to be Fickian diffusion type and exhibiting linear relationship between drug release (Q) vs. square root of time (t0.5). The in vitro skin permeation of drug from transdermal drug delivery system (TDDS) was evaluated using dermatomed pig skin. The product which shows in vitro drug skin permeation near to 64 mcg/h/ml was selected for in vivo studies. The in vivo studies revealed that Ma EC HPMC 46 is most effective among the other polymeric matrix TDDS. The AUC0-28 with Ma EC HPMC 46 was better than orally administered conventional doses at twelve hours interval (AUC0-28 1587 ng h/ml) as well as no trough and peaks in drug plasma level was recorded with TDDS. Hence, it could be concluded that the designed polymeric matrix TDDS of atenolol could be used successfully for effective and prolonged delivery of atenolol. However, it further demands exploration in clinic, an insight vision towards the development of TDDS for commercial use.

Transferrin coupled liposomes as drug delivery carriers for brain targeting of 5-florouracil

Diseases and disorders of the brain are extremely difficult to treat pharmacologically because most drugs are unable to pass across the blood--brain barriers. Complex multi-strand tight junctions between adjacent cerebral endothelial cells and between choroid plexus epithelial cells form a physical barrier and prevent the passage of water soluble drugs from the blood into the brain, whereas the inward passage of lipid soluble drugs is restricted by drug efflux pumps which act as a functional barrier. In the present work, a transferrin-coupled liposomal system for brain delivery of 5-florouracil has been investigated.5-florouracil and (99m)Tc-DTPA bearing non-coupled liposomes were prepared by cast film method, which were coupled with the transferrin by incubating these liposomes with transferrin in the presence of the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in saline phosphate buffer (pH 7.4). These liposomal systems were characterized for vesicle size, percent drug entrapment, and in vitro drug release. The size of the liposomes was increased on coupling with transferrin while percent drug entrapment reduced. The results of the in vitro release profile demonstrated that non-coupled liposomal formulation releases a comparatively higher percent (i.e. 74.8+/-3.21%) of drug than coupled liposomes. Results of in vivo study suggested a selective uptake of the transferrin-coupled liposomes from the brain capillary endothelial cells. In case of coupled liposomes, the level of radioactivity was 17-fold more as compared to the free radioactive agent and 13 times more with the non-coupled liposomes. Therefore, it could be concluded that using transferrin coupled liposomes the brain uptake of the drug could be enhanced.

Potential of Guar Gum Microspheres for Target Specific Drug Release to Colon

Various approaches for colon targeted drug delivery have been studied over the last decade including, pro-drugs, timed-released systems, coating of pH-dependant polymer and the use of polysaccharides. In the present work, a novel formulation consisting of cross-linked microspheres of guar gum has been investigated for colon-targeted delivery of metronidazole. An emulsification method involving the dispersion of aqueous solution of guar gum in castor oil was used to prepare spherical microspheres. Process parameters were analyzed in order to optimize the formulation. Shape and surface morphology of the microspheres were examined using scanning electron microscopy. Placebo microspheres exhibited a smooth surface while the incorporation of drug imparted a slight roughness to the surface texture. Particle size of the microspheres was determined using laser diffraction particle size analyzer. The in vitro drug release studies were performed in simulated gastric fluid for 2 h and intestinal fluid for 3 h, which revealed that the drug was retained comfortably inside the microspheres and that only 15.27+/-0.56% of the drug was released in 5 h. In vitro release rate studies were also carried out in simulated colonic fluid (SCF) in the presence of rat cecal contents, which showed improved drug release. Moreover, to induce the enzymes that specifically act on guar gum, the rats were treated with 1 ml of 1% w/v dispersion of guar gum for 2, 4 and 6 days and release rate studies were repeated in SCF in the presence of 2 and 4% w/v of cecal matter. A marked improvement in the drug release was observed in presence of cecal matter obtained after induction when compared to those without induction. In vitro release studies exhibited 31.23+/-1.49% drug release in 24 h in dissolution medium without rat cecal matter. However, the incorporation of 4% w/v cecal matter obtained after 6 days of enzymes induction increased the drug release to 96.24+/-4.77%.

The role of antibiotic prophylaxis in mesh repair of primary inguinal hernias using prolene hernia system: a randomized prospective double-blind control trial

Antibiotic prophylaxis is being commonly used in mesh repair of inguinal hernia but its role has been questioned in a recent Cochrane analysis performed in 2003. Routine use of antibiotic prophylaxis in mesh repair of inguinal hernia can lead to bacterial resistance and increase in cost. In a present double-blind placebo controlled trial involving 120 patients undergoing inguinal hernia repair using prolene hernia system, we did not find any benefit of the routine use of antibiotic prophylaxis in terms of wound infection rate.

Transferrin-conjugated liposomal system for improved delivery of 5-fluorouracil to brain

The objective of this study is to achieve the enhanced delivery of 5-fluorouracil to brain through transferrin-coupled liposomes. 5-Fluorouracil-loaded liposomes were prepared by cast film method and characterized for particle size, shape, percent encapsulation efficiency and in vitro drug release. Biodistribution studies were carried out with the help of radiolabelled 5-fluorouracil. 5-Fluorouracil was labelled with (99m)Tc-DTPA by oxidation-reduction method using stannous chloride and optimized for labelling parameters to get a high labelling efficiency. The in vitro stability was determined to check the efficiency of a system to find out the suitability of the radiolabelled system for in vivo studies. (99m)Tc-DTPA-labelled 5-fluorouracil bearing non-coupled and coupled liposomes were administered intravenously and biodistribution studies were performed. The distribution of 5-fluorouracil via non-coupled and coupled liposomes was determined in various organs, such as lungs, liver, kidneys, spleen and brain, by measuring the radioactivity using a gamma scintillation unit. The results of in vivo studies confirmed a selective uptake of the transferrin-coupled liposomes from the brain capillary endothelial cells. An average of 10-fold increase in the brain uptake of the drug was observed after the liposomal delivery of 5-fluorouracil, while the transferrin-coupled liposomes caused a 17-fold increase in the brain uptake of 5-fluorouracil. Therefore, it can be concluded that transferrin-coupled liposomes enhance the brain uptake of the drug, like 5-fluorouracil.

Role of cyanoacrylate in the management of low fistula in ano: a prospective study

BACKGROUND AND AIMS

Fistulotomy has remained the gold standard in the management of fistula in ano, especially low fistula in ano. Although highly effective in the management of fistula in ano, fistulotomy is associated with considerable discomfort and incontinence. This study was designed to evaluate the role of cyanoacrylate in the management of low fistula in ano. We present our short-term results with a 6-month follow-up.

MATERIALS AND METHODS

Twenty patients were enrolled in the study as day cases. Patients were analyzed clinically and then subjected to trans-anal ultrasound, as diagnosis of internal opening was not palpable on per rectal examination. The fistula tracks were probed and washed with saline, and granulation tissue at external opening was debrided. The glue was then injected into the fistulous track from a syringe nozzle through an infant feeding tube. Patients were further examined in the outpatient department until 6 months.

RESULTS

Seventeen patients got healed with primary injection with stoppage of any discharge from the fistulous track. The other two patients required one more injection and showed no signs of discharge thereafter. One patient who had two external openings continued to discharge from one opening even after two injections.

CONCLUSIONS

Cyanoacrylate glue can be offered as an effective alternative to surgery in patients suffering from fistula in ano as it is easy, safe, non-invasive, and effective.

Optimized conditions for high-level expression and purification of recombinant human interleukin-2 in E. coli

Interleukin-2 (IL-2), a potent cytokine has been used in anti-cancer therapy for over a decade now. IL-2, originally identified as a growth factor for T lymphocytes is a 15 kDa hydrophobic glycoprotein that induces the activation, clonal proliferation and differentiation of T and B-lymphocytes and enhances the cytotoxicity of monocytes and natural killer (NK) cells. Here, we report a simple method for the cloning, high-level expression and purification of IL-2 protein, which can be easily extended to other bioactive therapeutic proteins. The IL-2 gene was amplified from human spleen cDNA and cloned in a prokaryotic (E. coli) expression system. An optimal expression of the IL-2 protein was determined by varying the expression conditions like temperature, inducer concentration and duration of induction. The protein was expressed as inclusion bodies and a panel of reagents including detergents, urea and guanidine hydrochloride were used to solubilize it. After solubilization, the protein was renatured and subjected to a single step gel-filtration chromatography to yield immunobioactive IL-2 protein with > 99% purity.