UNDERSTANDING THE VITAL DETERMINANTS SHAPING LEARNERS' PHYSICAL ACTIVITYAND PSYCHOEMOTIONAL WELLBEING IN THE COVID-19 PERIOD

The Corona Virus (COV-19) epidemic significantly affected the educational environment, requiring a quick transition to distance and blended learning methods. This extraordinary disruption had an incredible impact on pupil's levels of physical activity (PA), psycho-emotional health (PEH) and engagement with academic material. The research aims to examine the vital determinants that influenced various areas of learners' lives during CoV-19. The purpose of this 600-person study was to collect data on the subjects' overall health and PA levels for the CoV-19 pandemic. The SPSS application was used to process the questionnaire's collected data. The information given reveals the respondents' degree of PA throughout the quarantine. According to the breakdown, 15% indicated low levels of PA, 39% reported medium levels and 46% reported high levels. The data show that, despite the respondents' different levels of PA, little PA predominated for most of them. The limitations of distance learning throughout quarantine and the prevalent recommendation of leaving residence for necessary reasons were blamed for this tendency. There were fewer prospects for higher-intensity PA due to these circumstances.

Relationship between online cognition and personality traits: A questionnaire based study of medical college students

Introduction

Current classification systems are not sure where to place the internet use disorder. Is it an addiction, an impulse control disorder, a consequence of another psychiatric morbidity or a consequence of personality trait/personality disorder?

Objectives

We intended to study which personality traits associated with online cognition may contribute towards Problematic internet use(PIU). We also analysed the relationship between number of hours of use/week of internet and PIU along with its relation with two ‘screening’ questions.

Methods

Online cognition scale and Abbreviated Eysenck Personality questionnaires were our measurements of choice in addition to demographic measures and some questions pertaining to online behaviour patterns.

Results

Total 163 responses were analysed. The demographic pools consisted mostly of young adults who had, on average, used the internet for 5.2 years at present rate of 21.81hours/week. We observed significantly higher mean OCS scores in men, in people who thought that the internet interfered with their lives and in those who felt the need to ‘cut-down’. A moderate positive and significant correlation was observed between hpurs/week of internet use and OCS scores. Also, significant positive correlation was observed between Neuroticism and OCS, impulsivity, and loneliness/depression scores. Significant negative correlations were observed between the Lie trait and impulse control. Neuroticism and Lie together contributed to 21.8% of variance in OCS scores.

Conclusions

Neuroticism and Lie traits (representing need for social acceptance) were found to the causing significamn varience in the OCS scores of the subjects. High number of hours/week use of internet was related to the feeling of ‘need to cut down use’.

Clinical Efficacy of Subgingivally Delivered Punica Granatum Chip and Gel in Management of Chronic Periodontitis Patients

Background Periodontitis has a multifactorial etiology, and the pathogenic bacteria that reside in the subgingival area are the primary etiologic agent. Objective The study aimed to evaluate the clinical efficacy and benefits of herbal chip and gel made from extracts of Punica granatum as a subgingival adjunct to scaling and root planing (SRP). Method A randomized control clinical trial was conducted on 30 systemically healthy patient's sites having chronic periodontitis, and they were randomly allocated to into three treatment groups followed by Scaling and Root Planing in all patients. Group 1 - Ten patients received Scaling and Root Planing and Punica granatum chip at selected sites. Group 2 - Ten patients received Scaling and Root Planing and punica granatum gel at selected sites. Group 3 - Ten patients with Scaling and Root Planing alone. Clinical parameters were recorded at baseline, 21 days and at 45 days which included plaque index (PI), gingival index (GI), probing pocket depth (PPD) and relative attachment level (RAL). Result Plaque Index and Gingival index showed better reduction in group I compared to group II and group III at 21st day 45th day follow up. Analysing Pocket Probing Depth the intergroup comparison revealed similar results with maximum reduction being seen in group I from baseline to 21 and baseline to 45 days (p < 0.001). On analysing Relative Attachment Loss revealed reduction in all three groups with maximum reduction in group I from baseline to 45 days and reduction in group III was not statistically significant (p < 0.090). Conclusion The study concluded that Punica granatum chip as an adjunct to Scaling and Root Planing was more effective than Punica granatum gel and scaling and root planing alone.

Structural and Optical Properties of Self-Assembled Epitaxially Grown GaN Nanorods and Nanoporous Film on Sapphire (0001) Using Laser Molecular Beam Epitaxy

The GaN nanoporous-film (NPF) and nanorods (NRs) were grown on sapphire (0001) using laserassisted molecular beam epitaxy (LMBE) technique by laser ablating solid GaN target at different laser energy density. The interconnected GaN NPF was grown at low laser energy density of ˜4 J/cm² whereas vertically aligned GaN NRs was obtained at high laser energy density of ˜7 J/cm². The pore size of the GaN NPF structure is in range of 40-120 nm. The GaN NRs possess hexagonal shape with six sidewall facets and truncated top facet. The length, width and density of GaN NRs are 600-900 nm, 150-250 nm and ˜2.5×10⁷ cm^-2, respectively. The X-ray rocking curve full width at half maximum values along GaN (0002) and (1012) planes for GaN NRs obtained to be 0.41 and 0.53°, respectively. The biaxial stress in hetero-epitaxially grown GaN was investigated with Raman spectroscopy and it was found that GaN NRs possesses a very low in-plane compressive biaxial stress of 0.09 GPa. The photoluminescence study exhibits a sharp band-to-band emission at 3.4 eV with a peak line width of 140 meV, signifying the good optical quality of the LMBE grown GaN NRs on sapphire (0001).

Excitation Density Dependent Photoluminescence Studies on Homo-Epitaxial GaN Nanowall Networks Grown by Laser Assisted Molecular Beam Epitaxy

The optical properties of laser-assisted molecular beam epitaxy grown homo-epitaxialGaN nanowall networks (NWNs) were investigated using power dependent photoluminescence (PL) spectroscopy and compared with homo-epitaxial GaN thin film. The pore size and tip width of GaN NWN sample is ˜120-180 nm and 10-15 nm, respectively. The ultraviolet-visible spectroscopy study shows that the GaN NWNs have low optical light reflection and minimum Fabry-Perot cavity effect than GaN film. The room temperature PL spectroscopy reveals that the GaN NWNs possesses enhanced band gap of 3.51 eV with blue shift of 90 meV than the GaN film (3.42 eV). The excitation density dependent PL spectroscopy measurements reveal that the GaN NWNs nanowall and near band emission (NBE) peak position and its linewidth invariant. The intensity of NBE peak for GaN film and nanowalls varies linearly whereas NBE to defect related yellow luminescence peak intensity ratio shows a non-linear variation on the excitation density. The excitation density in PL measurements plays a key role when the sample quality compared on the basis of PL data.

Structural and Optical Properties of GaN Film on Copper and Graphene/Copper Metal Foils Grown by Laser Molecular Beam Epitaxy

We report the direct growth of crystalline GaN on bare copper (Cu) and monolayer-graphene/Cu metal foils using laser molecular beam epitaxy technique at growth temperature of 700 °C. The surface morphology investigated with field emission scanning electron microscopy revealed that the size of GaN grains for film grown on bare Cu falls in range of 90 to 160 nm whereas large grains with size of ˜200 to 600 nm was obtained for GaN grown on graphene/Cu foil under similar growth condition. The transverse optical mode of cubic GaN and E₂ (high) phonon mode for wurtzite GaN phases were obtained on the GaN film grown on Cu and graphene/Cu metal foils as deduced by Raman spectroscopy. The photoluminescence (PL) spectroscopy studies showed that the near band edge emission peaks for GaN on Cu and graphene/Cu consist two major peaks at 3.26 and 3.4 eV, corresponding to cubic and wurtzite GaN, respectively. The Raman and PL studies disclosed that the mixed phase growth of GaN occurs on these foils and better structural and optical quality for GaN on graphene/Cu foil. The direct growth of GaN on two dimensional graphene on polycrystalline metal foils is beneficial various transferrable and flexible opto-electronics device applications.

Effect of surface modification and laser repetition rate on growth, structural, electronic and optical properties of GaN nanorods on flexible Ti metal foil

The effect of flexible Ti metal foil surface modification and laser repetition rate in laser molecular beam epitaxy growth process on the evolution of GaN nanorods and their structural, electronic and optical properties has been investigated. The GaN nanostructures were grown on bare- and pre-nitridated Ti foil substrates at 700 °C for different laser repetition rates (10–30 Hz). It is found that the low repetition rate (10 Hz) promotes sparse growth of three-dimensional inverted-cone like GaN nanostructures on pre-nitridated Ti surface whereas the entire Ti foil substrate is nearly covered with film-like GaN consisting of large-sized grains for 30 Hz growth. In case of the GaN growth at 20 Hz, uniformly-aligned, dense (∼8 × 10⁹ cm⁻²) GaN nanorods are successfully grown on pre-nitridated Ti foil whereas sparse vertical GaN nanorods have been obtained on bare Ti foil under similar growth conditions for both 20 and 30 Hz. X-ray photoemission spectroscopy (XPS) has been utilized to elucidate the electronic structure of GaN nanorods grown under various experimental conditions on Ti foil. It confirms Ga–N bonding in the grown structures, and the calculated chemical composition turns out to be Ga rich for the GaN nanorods grown on pre-nitridated Ti foil. For bare Ti substrates, a preferred reaction between Ti and N is noticed as compared to Ga and N leading to sparse growth of GaN nanorods. Hence, the nitridation of Ti foil is a prerequisite to achieve the growth of dense and aligned GaN nanorod arrays. The X-ray diffraction, high resolution transmission electron microscopy and Raman studies revealed the c-axis growth of wurtzite GaN nanorods on Ti metal foil with good crystallinity and structural quality. The photoluminescence spectroscopy showed that the dense GaN nanorod possesses a near band edge emission at 3.42 eV with a full width at half maximum of 98 meV at room temperature. The density-controlled growth of GaN nanorods on a flexible substrate with high structural and optical quality holds promise for potential applications in futuristic flexible GaN based optoelectronics and sensor devices.

The effect of flexible Ti metal foil surface modification and laser repetition rate in laser molecular beam epitaxy growth process on the evolution of GaN nanorods and their structural, electronic and optical properties has been investigated.

A quinoline compound inhibits the replication of dengue virus serotypes 1-4 in Vero cells

BACKGROUND

The global occurrence of dengue, a mosquito-​borne viral disease caused by four distinct dengue viruses (DENV-1, -2, -3 and -4), is reported to have increased approximately 30-fold in the last 50 years, causing approximately 400 million infections a year. A limited use, sub-optimal live attenuated dengue vaccine has become available recently. It is becoming apparent that antibodies to DENVs can promote infection by Zika virus (ZIKV), a related mosquito-borne flavivirus. A drug to treat these flaviviral infections continues to be an unmet public health need.

METHODS

We screened an 'in-house' library of approximately 2,000 small molecules for inhibitors of cloned DENV-2 protease. Putative inhibitor binding to DENV-2 protease was analysed by in silico docking. Anti-DENV activity was analysed by monitoring viral antigen synthesis by ELISA, viral RNA synthesis by reverse-transcription​ coupled to real-time polymerase chain reaction and infectious virus production by plaque assay, in DENV-infected Vero cells.

RESULTS

A quinoline derivative, BT24, was identified for the first time as a potent inhibitor of the cloned DENV-2 protease (half maximal inhibitory concentration [IC₅₀]=0.5 µM). In silico analysis revealed that BT24 binds to an allosteric site in the vicinity of the active site of DENV-2 protease. Cell-based assays demonstrated that BT24 can inhibit all four DENVs in infected Vero cells.

CONCLUSIONS

BT24 is a DENV-2 protease inhibitor which manifests the capacity to inhibit the replication of all four DENVs in cultured cells. It may provide a lead for a pan-DENV inhibitory drug.

A tetravalent virus-like particle vaccine designed to display domain III of dengue envelope proteins induces multi-serotype neutralizing antibodies in mice and macaques which confer protection against antibody dependent enhancement in AG129 mice

Background

Dengue is one of the fastest spreading vector-borne diseases, caused by four antigenically distinct dengue viruses (DENVs). Antibodies against DENVs are responsible for both protection as well as pathogenesis. A vaccine that is safe for and efficacious in all people irrespective of their age and domicile is still an unmet need. It is becoming increasingly apparent that vaccine design must eliminate epitopes implicated in the induction of infection-enhancing antibodies.

Methodology/principal findings

We report a Pichia pastoris-expressed dengue immunogen, DSV4, based on DENV envelope protein domain III (EDIII), which contains well-characterized serotype-specific and cross-reactive epitopes. In natural infection, <10% of the total neutralizing antibody response is EDIII-directed. Yet, this is a functionally relevant domain which interacts with the host cell surface receptor. DSV4 was designed by in-frame fusion of EDIII of all four DENV serotypes and hepatitis B surface (S) antigen and co-expressed with unfused S antigen to form mosaic virus-like particles (VLPs). These VLPs displayed EDIIIs of all four DENV serotypes based on probing with a battery of serotype-specific anti-EDIII monoclonal antibodies. The DSV4 VLPs were highly immunogenic, inducing potent and durable neutralizing antibodies against all four DENV serotypes encompassing multiple genotypes, in mice and macaques. DSV4-induced murine antibodies suppressed viremia in AG129 mice and conferred protection against lethal DENV-4 virus challenge. Further, neither murine nor macaque anti-DSV4 antibodies promoted mortality or inflammatory cytokine production when passively transferred and tested in an in vivo dengue disease enhancement model of AG129 mice.

Conclusions/significance

Directing the immune response to a non-immunodominant but functionally relevant serotype-specific dengue epitope of the four DENV serotypes, displayed on a VLP platform, can help minimize the risk of inducing disease-enhancing antibodies while eliciting effective tetravalent seroconversion. DSV4 has a significant potential to emerge as a safe, efficacious and inexpensive subunit dengue vaccine candidate.

Dengue is mosquito-borne viral disease which is currently a global public health problem. It is caused by four different types of dengue viruses. Nearly a 100 million people a year suffer from overt sickness, which may range from mild fever to potentially fatal disease. A virus-based dengue vaccine was launched for the first time in late 2015. Unexpectedly, this vaccine mimics the dengue viruses in that it appears to elicit disease-enhancing antibodies. To reduce such risk, safer vaccines that eliminate viral proteins responsible for undesirable antibodies are needed. We focused our attention on a small domain of the dengue virus surface protein known as envelope domain III (EDIII). Humans make only a small amount of antibodies against EDIII, but these antibodies are effective in blocking dengue virus from entering cells. We used a yeast expression system to display EDIIIs of all four types of dengue viruses on the surface of non-infectious virus-like particles (VLPs). These VLPs elicited antibodies, in mice and monkeys, which blocked all four dengue virus types and their variants from entering cells in culture. Importantly, these antibodies did not enhance dengue infection in a mouse model.

Cissampelos pareira Linn: Natural Source of Potent Antiviral Activity against All Four Dengue Virus Serotypes

BACKGROUND

Dengue, a mosquito-borne viral disease, poses a significant global public health risk. In tropical countries such as India where periodic dengue outbreaks can be correlated to the high prevalence of the mosquito vector, circulation of all four dengue viruses (DENVs) and the high population density, a drug for dengue is being increasingly recognized as an unmet public health need.

METHODOLOGY/PRINCIPAL FINDINGS

Using the knowledge of traditional Indian medicine, Ayurveda, we developed a systematic bioassay-guided screening approach to explore the indigenous herbal bio-resource to identify plants with pan-DENV inhibitory activity. Our results show that the alcoholic extract of Cissampelos pariera Linn (Cipa extract) was a potent inhibitor of all four DENVs in cell-based assays, assessed in terms of viral NS1 antigen secretion using ELISA, as well as viral replication, based on plaque assays. Virus yield reduction assays showed that Cipa extract could decrease viral titers by an order of magnitude. The extract conferred statistically significant protection against DENV infection using the AG129 mouse model. A preliminary evaluation of the clinical relevance of Cipa extract showed that it had no adverse effects on platelet counts and RBC viability. In addition to inherent antipyretic activity in Wistar rats, it possessed the ability to down-regulate the production of TNF-α, a cytokine implicated in severe dengue disease. Importantly, it showed no evidence of toxicity in Wistar rats, when administered at doses as high as 2g/Kg body weight for up to 1 week.

CONCLUSIONS/SIGNIFICANCE

Our findings above, taken in the context of the human safety of Cipa, based on its use in Indian traditional medicine, warrant further work to explore Cipa as a source for the development of an inexpensive herbal formulation for dengue therapy. This may be of practical relevance to a dengue-endemic resource-poor country such as India.

Pichia pastoris-expressed dengue 3 envelope-based virus-like particles elicit predominantly domain III-focused high titer neutralizing antibodies

Dengue poses a serious public health risk to nearly half the global population. It causes ~400 million infections annually and is considered to be one of the fastest spreading vector-borne diseases. Four distinct serotypes of dengue viruses (DENV-1, -2, -3, and -4) cause dengue disease, which may be either mild or extremely severe. Antibody-dependent enhancement (ADE), by pre-existing cross-reactive antibodies, is considered to be the major mechanism underlying severe disease. This mandates that a preventive vaccine must confer simultaneous and durable immunity to each of the four prevalent DENV serotypes. Recently, we used Pichia pastoris, to express recombinant DENV-2 E ectodomain, and found that it assembled into virus-like particles (VLPs), in the absence of prM, implicated in the elicitation of ADE-mediating antibodies. These VLPs elicited predominantly type-specific neutralizing antibodies that conferred significant protection against lethal DENV-2 challenge, in a mouse model. The current work is an extension of this approach to develop prM-lacking DENV-3 E VLPs. Our data reveal that P. pastoris-produced DENV-3 E VLPs not only preserve the antigenic integrity of the major neutralizing epitopes, but also elicit potent DENV-3 virus-neutralizing antibodies. Further, these neutralizing antibodies appear to be exclusively directed toward domain III of the DENV-3 E VLPs. Significantly, they also lack discernible ADE potential toward heterotypic DENVs. Taken together with the high productivity of the P. pastoris expression system, this approach could potentially pave the way toward developing a DENV E-based, inexpensive, safe, and efficacious tetravalent sub-unit vaccine, for use in resource-poor dengue endemic countries.

A small molecule inhibitor of dengue virus type 2 protease inhibits the replication of all four dengue virus serotypes in cell culture

Background

Dengue has emerged as the most significant of arboviral diseases in the 21st century. It is endemic to >100 tropical and sub-tropical countries around the world placing an estimated 3.6 billion people at risk. It is caused by four genetically similar but antigenically distinct, serotypes of dengue viruses. There is neither a vaccine to prevent nor a drug to treat dengue infections, at the present time. The major objective of this work was to explore the possibility of identifying a small molecule inhibitor of the dengue virus protease and assessing its ability to suppress viral replication in cultured cells.

Methods

We cloned, expressed and purified recombinant dengue virus type 2 protease. Using an optimized and validated fluorogenic peptide substrate cleavage assay to monitor the activity of this cloned dengue protease we randomly screened ~1000 small molecules from an ‘in-house’ library to identify potential dengue protease inhibitors.

Results

A benzimidazole derivative, named MB21, was found to be the most potent in inhibiting the cloned protease (IC₅₀ = 5.95 μM). In silico docking analysis indicated that MB21 binds to the protease in the vicinity of the active site. Analysis of kinetic parameters of the enzyme reaction suggested that MB21 presumably functions as a mixed type inhibitor. Significantly, this molecule identified as an inhibitor of dengue type 2 protease was also effective in inhibiting each one of the four serotypes of dengue viruses in infected cells in culture, based on analysis of viral antigen synthesis and infectious virus production. Interestingly, MB21 did not manifest any discernible cytotoxicity.

Conclusions

This work strengthens the notion that a single drug molecule can be effective against all four dengue virus serotypes. The molecule MB21 could be a potential candidate for ‘hit-to-lead’ optimization, and may pave the way towards developing a pan-dengue virus antiviral drug.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-015-0248-x) contains supplementary material, which is available to authorized users.

Pelvic organ cross-sensitization to enhance bladder and urethral pain behaviors in rats with experimental colitis

Neural cross-sensitization has been postulated as a mechanism underlying overlaps of chronic pelvic pain disorders such as bladder pain syndrome/interstitial cystitis (BPS/IC) and irritable bowel syndrome (IBS). Animals with experimental colitis have been used to study the underlying mechanisms for overlapped pelvic pain symptoms, and shown to exhibit bladder overactivity evidenced by frequent voiding; however, it has not directly been evaluated whether pain sensation derived from the lower urinary tract is enhanced in colitis models. Also, the cross-sensitization between the colon and urethra has not been studied previously. In the present study, we therefore investigated pain behaviors induced by nociceptive stimuli in the lower urinary tract and the involvement of C-fiber afferent pathways using rats with colitis induced by intracolonic application of 2,4,6-trinitrobenzenesulfonic acid (TNBS). In TNBS-induced colitis rats at 10 days, intravesical application of resiniferatoxin (RTx) induced a significantly greater number of episodes of both licking and freezing behaviors, which were reduced by capsaicin-sensitive C-fiber afferent desensitization. Histochemical studies using fluorescent dye tracers injected into the colon, bladder or urethra showed that dichotomized afferent neurons comprised 6.9-14.5% of L1, L6 and S1 dorsal root ganglion (DRG) neurons innervating the colon or the lower urinary tract. Transient receptor potential vanilloid 1 (TRPV1) mRNA expression was significantly increased in, the bladder, urethra and S1 DRG in colitis rats. An increase in myeloperoxidase (MPO) activity was found in the colon, but not in the bladder or urethra after intracolonic TNBS treatment. These results indicate that TNBS-induced colitis increased pain sensitivity in the bladder and urethra via activation of C-fiber afferent pathways due to colon-to-bladder and colon-to-urethral cross-sensitization, suggesting the contribution of pelvic organ cross-sensitization mechanisms to overlapped pain symptoms in BPS/IC and IBS.

Dengue-specific subviral nanoparticles: design, creation and characterization

Background

Dengue is today the most significant of arboviral diseases. Novel tools are necessary to effectively address the problem of dengue. Virus-like particles (VLP) offer a versatile nanoscale platform for developing tools with potential biomedical applications. From the perspective of a potentially useful dengue-specific tool, the dengue virus envelope protein domain III (EDIII), endowed with serotype-specificity, host receptor recognition and the capacity to elicit virus-neutralizing antibodies, is an attractive candidate.

Methods

We have developed a strategy to co-express and co-purify Hepatitis B virus surface (S) antigen in two forms: independently and as a fusion with EDIII. We characterized these physically and functionally.

Results

The two forms of the S antigen associate into VLPs. The ability of these to display EDIII in a functionally accessible manner is dependent upon the relative levels of the two forms of the S antigen. Mosaic VLPs containing the fused and un-fused components in 1:4 ratio displayed maximal functional competence.

Conclusions

VLPs armed with EDIII may be potentially useful in diagnostic, therapeutic and prophylactic applications.

Pichia pastoris-expressed dengue 2 envelope forms virus-like particles without pre-membrane protein and induces high titer neutralizing antibodies

Dengue is a mosquito-borne viral disease with a global prevalence. It is caused by four closely-related dengue viruses (DENVs 1–4). A dengue vaccine that can protect against all four viruses is an unmet public health need. Live attenuated vaccine development efforts have encountered unexpected interactions between the vaccine viruses, raising safety concerns. This has emphasized the need to explore non-replicating dengue vaccine options. Virus-like particles (VLPs) which can elicit robust immunity in the absence of infection offer potential promise for the development of non-replicating dengue vaccine alternatives. We have used the methylotrophic yeast Pichia pastoris to develop DENV envelope (E) protein-based VLPs. We designed a synthetic codon-optimized gene, encoding the N-terminal 395 amino acid residues of the DENV-2 E protein. It also included 5’ pre-membrane-derived signal peptide-encoding sequences to ensure proper translational processing, and 3’ 6× His tag-encoding sequences to facilitate purification of the expressed protein. This gene was integrated into the genome of P. pastoris host and expressed under the alcohol oxidase 1 promoter by methanol induction. Recombinant DENV-2 protein, which was present in the insoluble membrane fraction, was extracted and purified using Ni²⁺-affinity chromatography under denaturing conditions. Amino terminal sequencing and detection of glycosylation indicated that DENV-2 E had undergone proper post-translational processing. Electron microscopy revealed the presence of discrete VLPs in the purified protein preparation after dialysis. The E protein present in these VLPs was recognized by two different conformation-sensitive monoclonal antibodies. Low doses of DENV-2 E VLPs formulated in alum were immunogenic in inbred and outbred mice eliciting virus neutralizing titers >1∶1200 in flow cytometry based assays and protected AG129 mice against lethal challenge (p<0.05). The formation of immunogenic DENV-2 E VLPs in the absence of pre-membrane protein highlights the potential of P. pastoris in developing non-replicating, safe, efficacious and affordable dengue vaccine.

Synthesis of Bisphosphodiester Surfactants Derived from Tetradecanol and Different Methylene Chains as a Spacer Derived from α-ω-Alkyl Dibromides

Bisphosphodiester surfactant is a name assigned to a family of synthetic amphiphiles possessing a hydrocarbon chain attached to another hydrocarbon chain via different methylene chains as a spacer derived from α-ω-alkyl dibromide (1,4-DBB, 1,6-DBH and 1,8-DBO). In the present study, a series of bisphosphodiester surfactants having C14 hydrophobic tail and different methylene chains as a spacer derived from α-ω-alkyl dibromide have been synthesized at 35°C. The effect of reaction variables like temperature, duration and molar ratios of mono tetradecyl phosphate, tetramethyl ammonium hydroxide and spacer on the yield of bisphosphodiester surfactants has also been reported. Modern instrumental techniques viz. FT-IR, 1HNMR, and 13CNMR were utilized to characterize the functional groups presence in synthesized bisphosphodiester surfactants. Elemental analysis of synthesized bisphosphodiester surfactants was also carried out. Surface active properties viz. surface tension, interfacial tension, critical micelle concentration and aqueous properties viz. foaming stability, wetting ability, emulsifying ability and dispersing power of synthesized gemini surfactants were also determined. Among all synthesized bisphosphodiester surfactants IIIb had maximum anionic content of 78.9%; and showed highest foaming ability (70 ml), superior dispersing ability (45.7%), whereas IIIc showed low CMC values (0.00026 mmol/l); minimum surface tension and interfacial tension (37.3 mN/m and 31.6 mN/m) respectively.

Synthesis, Structural Properties and Applications of Gemini Surfactants: A Review

Gemini surfactants are most exciting new types of surfactants. They have two hydrophilic head groups and two hydrophobic groups in a molecule separated by a spacer group. Nowadays different types of geminis have been synthesized. Geminis show some characteristic features like low cmc, high surface activity, high solubility in water, good foaming and wetting properties, as well as low Krafft temperature. Geminis imply low eye and skin irritation. These surfactants are widely used as antifoaming and antimicrobial agents. This review paper deals with synthesis, properties and applications of various gemini surfactants.

Synthesis and Properties of Di-n-hexadecyl-α,ω-Alkyl Bisphosphate Surfactants

Amphipatic compounds with connecting group between two lipophilic groups were prepared by phosphorylating a long chain alcohol (hexadecanol) with pyrophosphoric acid to prepare hexadecyl phosphate. Then the resulting hexadecyl phosphate was used to prepare bisphosphate surfactants with terminal dibromo alkanes viz. 1,4-dibromo butane or 1,6-dibromo hexane or 1,8-dibromo octane using acetonitrile as solvent. The structure of synthesized products were verified by modern analytical techniques viz. FT-IR, and 1H-NMR. The disodium salts of bisphosphate surfactants were obtained by neutralization of free acid with sodium hydroxide. The performance properties viz. foaming, wetting, emulsifying ability and anionic content of synthesized surfactants were also evaluated. The synthesized bisphosphate surfactant with 1,6-dibromo hexane possessed maximum anionic content and showed good water solubility, foaming, wetting, and emulsifying ability compared to conventional analogs.

Virus-like particles displaying envelope domain III of dengue virus type 2 induce virus-specific antibody response in mice

OBJECTIVE

Currently, dengue represents one of the most significant arboviral disease worldwide, for which a vaccine is not yet available. Persistent challenges in live viral dengue vaccines have sparked a keen interest in exploring non-replicating dengue vaccines. We have examined the feasibility of using the methylotrophic yeast Pichia pastoris to develop a chimeric vaccine candidate displaying the dengue virus type-2 (DENV-2) envelope domain III (EDIII), implicated in host receptor binding and in the induction of virus-neutralizing antibodies, on the surface of non-infectious virus-like particles (VLP)-based on the Hepatitis B virus core antigen (HBcAg).

METHODS

We designed a fusion antigen by inserting DENV-2 EDIII into c/e1 loop of HBcAg. A codon-optimized gene encoding this fusion antigen was integrated into the genome of P. pastoris, under the control of the Alcohol Oxidase 1 promoter. The antigen was expressed by methanol induction and purified to near homogeneity by Ni(2+) affinity chromatography. The purified antigen was characterized physically and functionally to evaluate its ability to assemble into VLPs, and elicit DENV-2-specific antibodies in mice.

RESULTS

This fusion antigen was expressed successfully to high yields and purified to near homogeneity. Electron microscopy and competitive ELISA analyses showed that it formed VLPs in which the EDIII moiety was accessible to different EDIII-specific antibodies. These VLPs were immunogenic in mice, stimulating the production of antibodies that could specifically recognize DENV-2 and neutralize its infectivity. However, virus-neutralizing antibody titers were modest.

CONCLUSIONS

Our data show: (i) insertion of EDIII into the c/e1 loop of HBcAg does not compromise particle assembly; and (ii) the chimeric VLPs elicit a specific humoral response against DENV-2. The strategy of displaying dengue virus EDIII using a VLP platform will need further optimization before it may be developed into a viable alternative option.

Chimeric Hepatitis B core antigen virus-like particles displaying the envelope domain III of dengue virus type 2

Background

Dengue is a global public health problem for which no drug or vaccine is available. Currently, there is increasing interest in developing non-replicating dengue vaccines based on a discrete antigenic domain of the major structural protein of dengue viruses (DENVs), known as envelope domain III (EDIII). The use of bio-nanoparticles consisting of recombinant viral structural polypeptides, better known as virus-like particles (VLPs), has emerged as a potential platform technology for vaccine development. This work explores the feasibility of developing nanoparticles based on E. coli-expressed recombinant Hepatitis B virus core antigen (HBcAg) designed to display EDIII moiety of DENV on the surface.

Findings

We designed a synthetic gene construct encoding HBcAg containing an EDIII insert in its c/e1 loop. The fusion antigen HBcAg-EDIII-2 was expressed in E. coli, purified to near homogeneity using Ni⁺² affinity chromatography and demonstrated to assemble into discrete 35–40 nm VLPs by electron microscopy. Competitive ELISA analyses showed that the EDIII-2 moieties of the VLPs are accessible to anti-EDIII-2-specific monoclonal and polyclonal antibodies, suggesting that they are surface-displayed. The VLPs were highly immunogenic eliciting high titer anti-EDIII-2 antibodies that were able to recognize, bind and neutralize infectious DENV based on ELISA, immunofluorescence and virus-neutralization assays.

Conclusion

This work demonstrates that HBcAg-derived nanoparticles can serve as a useful platform for the display of DENV EDIII. The EDIII-displaying nanoparticles may have potential applications in diagnostics/vaccines for dengue.

Approach to Chronic Hepatitis B Virus Infection

Hepatitis B virus (HBV) infection constitutes one of the major global public health problems. Not only India and Nepal, East Asia is ghting with the same. About 30 percent of the world’s population has serological evidence of current or past infection with HBV. By virtue of its different stage of presentation in different age groups of patients and the rapid mutation in the virus, the treatment of HBV requires thorough work-up and regular monitoring. Many new concepts have evolved in last decade in managing these patients, such as HBV Genotype, HBV DNA quanti cation and mutation analysis. The introduction of oral antivirals in the treatment of HBV infection has revolutionized the treatment.

Approach to chronic hepatitis B virus infection

Hepatitis B virus (HBV) infection constitutes one of the major global public health problems. Not only India and Nepal, East Asia is fighting with the same. About 30 percent of the world's population has serological evidence of current or past infection with HBV. By virtue of its different stage of presentation in different age groups of patients and the rapid mutation in the virus, the treatment of HBV requires thorough work-up and regular monitoring. Many new concepts have evolved in last decade in managing these patients, such as HBV Genotype, HBV DNA quantification and mutation analysis. The introduction of oral antivirals in the treatment of HBV infection has revolutionized the treatment.

Evaluation of envelope domain III-based single chimeric tetravalent antigen and monovalent antigen mixtures for the detection of anti-dengue antibodies in human sera

Background

Flavivirus cross-reactive antibodies in human sera interfere with the definitive identification of dengue virus (DENV) infections especially in areas with multiple co-circulating flaviviruses. Use of DENV envelope domain-III (EDIII) can partially resolve the problem. This study has examined the effect of (i) incorporating the EDIIIs of four DENV serotypes into a single chimeric antigen, and (ii) immobilizing the antigen through specific interaction on the sensitivity and specificity of anti-DENV antibody detection.

Methods

A sera panel (n = 164) was assembled and characterized using commercial kits for infection by DENV and a host of other pathogens. Anti-DENV antibodies of both IgM and IgG classes in this panel were detected in indirect ELISAs using a mixture of monovalent EDIIIs, a chimeric EDIII-based tetravalent antigen, EDIII-T, and a biotinylated version of the latter as coating antigens. The sensitivity and specificity of these assays were compared to those obtained using the PanBio Dengue IgG/IgM ELISAs.

Results

The performance of dengue IgG and IgM indirect ELISAs, using either a physical mixture of four EDIIIs or the single chimeric EDIII-T antigen, were comparable. Coating of a biotinylated version of the tetravalent antigen on streptavidin plates enhanced sensitivity without compromising specificity.

Conclusions

The incorporation of the EDIIIs of the four DENV serotypes into a single chimeric antigen did not adversely affect assay outcome in indirect ELISAs. Oriented, rather than random, immobilization of the tetravalent antigen enhanced sensitivity of detection of anti-DENV antibodies with retention of 100% specificity.

Patternable nanowire sensors for electrochemical recording of dopamine

Spatially resolved electrochemical recording of neurochemicals is difficult due to the challenges associated with producing nanometer-scale patternable and integrated sensors. We describe the lithographic fabrication and characterization of patternable gold (Au) nanowire (NW) based sensors for the electrochemical recording of dopamine (DA). We demonstrate a straightforward NW-size-independent approach to align contact pads to NWs. Sensors, with NW widths as small as 30 nm, exhibited considerable insensitivity to scan rates during cyclic voltammetry, a nonlinear increase in oxidation current with increasing NW width, and the selectivity to measure submaximal synaptic concentrations of DA in the presence of interfering ascorbic acid. The electrochemical sensitivity of Au NW electrode sensors was much larger than that of Au thin-film electrodes. In chronoamperometric measurements, the NW sensors were found to be sensitive for submicromolar concentration of DA. Hence, the patternable NW sensors represent an attractive platform for electrochemical sensing and recording.

Immunology of mycobacterial infections: with special reference to Mycobacterium avium subspecies paratuberculosis

The interplay between mycobacteria and host determines the outcome of infection. After uptake of mycobacteria by macrophages, several possible scenarios may emerge; mycobacteria may be destroyed immediately or there is establishment of persistent infection. This review is focused around mycobacteria-host interactions with reference to Mycobacterium avium subspecies paratuberculosis (MAP) infection and highlights protective mechanisms involved in order to design vaccines and other control strategies.

Diaphragm disease of the ileum: a case report

Non-steroidal anti-inflammatory drugs induced diaphragm like lesions are a rare cause of small intestinal obstruction. They occur most commonly in elderly patients who have been consuming these drugs for prolonged periods for pain relief. We report the first case of ileal diaphragm disease from Asia. She responded well to localised resection of the diseased ileum. Intra-operative enteroscopy may be helpful in deciding the extent of intestinal resection.

Serological appraisal of malaria status in tribal area of Orissa, India

A cross-sectional seroepidemiological study conducted in 173 tribal residents (including all age groups) from three villages of Sundergarh district of Orissa using ELISA as a tool revealed high levels of antibody titres against both AR1 and Pf antigens. The mean +/- S.D. ELISA O.D. obtained for AR1 were 0.73 +/- 0.2, 1.037 +/- 0.196, 1.05 +/- 0.42 and for Pf, 0.70 +/- 0.2, 1.0 +/- 0.28, 0.94 +/- 0.4 respectively for Badramoli, Jharbeda and Boneikela population. Parasitological results showed high incidence of malaria in < 5 years age group in Badramoli and Boneikela villages when compared to other age groups. An. fluviatilis was found to be the principle malaria vector as found in the HBI results. High ELISA O.D. and high equivalent transmission index (ETI) indicate a high malaria transmission in the area. Seroepidemiological studies could be used for effective surveillance and stratification of endemicity in a given area which can help in executing intervention strategy for malaria control.

Encapsulation in cationic liposomes enhances antitumour efficacy and reduces the toxicity of etoposide, a topo-isomerase II inhibitor

Etoposide exerts its antineoplastic effect by forming a ternary complex with topo-isomerase II and DNA, leading to DNA breaks and cell death. However, it causes myelosuppression and its lipophilicity poses a major limitation during administration. Liposomes have been reported to increase the efficacy and reduce the toxicity of antineoplastic agents. Recent evidence suggests that cationic liposomes bind efficiently to tumours. The present study was thus designed to encapsulate etoposide in cationic liposomes and to evaluate its antitumour efficacy and systemic toxicity in comparison with a conventional parenteral formulation. Etoposide encapsulated in liposomes was synthesised by thin film hydration followed by an extrusion method. Fibrosarcoma was induced in mice by subcutaneous administration of 20-methylcholanthrene. Chemotherapy was started when the tumour reached 200 mm(3) in volume. Liposomal etoposide (10 mg/m(2)/day for 5 days) significantly delayed tumour growth as compared to non-liposomal etoposide. The median time of death was calculated to be 19.5, 26.25 and 56 days in vehicle-treated controls, non-liposomal-etoposide- and liposomal-etoposide-treated groups, respectively. A transient reduction in body weight was seen in both the liposomal- and non-liposomal-etoposide-treated groups. The maximum tolerated dose was however significantly higher in the group treated with liposomal etoposide, which also exhibited a lesser degree of myelosuppression than the animals treated with non-liposomal etoposide. The present findings suggest that cationic liposomes could be considered as potential for delivery of etoposide to tumours.

Etoposide encapsulated in positively charged liposomes: pharmacokinetic studies in mice and formulation stability studies

Etoposide is an antineoplastic agent which acts by forming a ternary complex with topoisomerase II and DNA, causing DNA breaks and cell death. In recent studies we have demonstrated that encapsulation in liposomes increases the antitumour efficacy and reduces the adverse effects associated with etoposide. The present study was thus conducted to evaluate whether encapsulation in cationic liposomes altered the pharmacokinetics of etoposide and to study the effect of cholesterol incorporation on the stability of the liposomes. Etoposide-encapsulated unilammellar liposomes were synthesized by thin film hydration followed by extrusion. The drug was administered to Swiss albino mice at a dose of 10 mg kg(-1). The concentration of the drug in plasma was analysed at different time points till 360 min after injection, using a h.p.l.c. method. The terbium chloride-dipicolinic acid interaction method was applied to study the stability of the formulation in mouse serum and also following storage at 0( composite function)C over a period of time. The effect of the free and liposomal drug on myelosuppression was evaluated at 10 mg m(-2)and 40 mg m(-2)dose levels by quantifying blood cell counts on day 15 and day 21 following a 5 day course of therapy. Encapsulation in cationic liposomes increased the area under the concentration vs time curve to 42.98 microghml(-1)from 24.18 microghml(-1)in the case of the free drug. Half-life (beta) was 58. 62 and 186 min in the case of free and liposomal etoposide, respectively. In the stability studies, incorporation of cholesterol progressively stabilized the formulation in serum. The use of sucrose at increasing concentrations as a cryoprotectant also increased the shelf stability of the formulation at 0( composite function)C. Toxicity studies using a dose of pure drug revealed that though myelosuppression was evident in both liposomal- and free drug-treated groups on day 15 it was reversed by day 21 following initiation of therapy. The present findings suggest that liposomes could serve as an alternative mode of delivery for etoposide.

Serological investigation of malaria outbreak in Thar desert of Rajasthan

A serological investigation by a repeat cross-sectional survey was conducted in Thar desert (Rajasthan) during and after one year of malaria outbreak to determine malaria endemicity using ELISA as a tool. The assay was based on indirect ELISA to measure antibody levels against a nonapeptide R1 (EENVEHDA-cys) derived from Pf 155/Resa and Plasmodium falciparum crude antigen. Finger prick blood samples were collected from individuals belonging to all age groups. Sera were tested at already standardized optimum dilution to detect antigen specific immunoglobulin isotype. The mean ELISA O.D. values 0.153 for anti R1 peptide and 0.162 for anti Pf antigen reflected the seronegative profile, when the focal malaria outbreak occurred in 1994. A substantial increase in antibody levels was detected in individuals after one year showing mean ELISA values for anti-R1 and anti-Pf antigens as 0.52 and 0.58 and seropositivity as 75.2% and 52% respectively. Data obtained from the present study indicate that serological survey could be done to assess the situation in case of reappearing or disappearing status of malaria in a defined population.

Mycoplasmal antibodies as determined with an enzyme-linked immunosorbent assay, in tubal factor infertility

A total of 81 infertile women, who had been referred for diagnostic loparoscopy, were tested for the presence of antibodies to Mycoplasma hominis and T-mycoplasma. Out of 81, 30 had tubal adhesions and 51 had unilateral/bilateral tubal blockage. Antibodies to M. hominis were found in 21/30 (70%) and 14/51 (27.45%) women, antibodies to T-mycoplasma in 12/20 (40% and 39/51 (76.47%) women with tubal disorder. In a control group of 40 pregnant women, antibodies to the same two organisms occurred in 10% and 32.5%. Antibodies to M. hominis and T-mycoplasma were significantly (P < 0.001) more common in women with tubal disorder. Our results confirm the important role of M. hominis and T-mycoplasma in the aetiology of tubal infertility.

Naturally occurring plasmodia-specific circulating immune complexes in individuals of malaria endemic areas in India

Blood samples collected from individuals belonging to malaria endemic areas were assayed for antigen-specific circulating immune complexes in polyethylene glycol precipitates of serum by enzyme immunoassay. Sera were tested from patients with acute P. vivax and P. falciparum infections, from clinically immune individuals and also from healthy normals. Circulating immune complexes (CICs) containing immunoglobulin G and M isotypes were found to be abundant in individuals with ongoing and past infections and also in clinically immune donors. In patients with acute infection but without any past history of malaria, CICs of IgM type were found to be significantly higher. Demonstration of antigen/antibody specific CICs could be a useful indicator of active, ongoing and recent/past infection, also of the status of immune responses of individuals belonging to various endemic areas.

Anti-inflammatory activity and pharmacokinetic profile of a new parenteral formulation of nimesulide

Nimesulide, a selective COX-2 inhibitor, exerts potent anti-inflammatory and analgesic effects when administered orally, rectally or topically. The present study was designed to evaluate the anti-inflammatory activity of a new parenteral formulation of nimesulide and to correlate it with the pharmacokinetic profile. Nimesulide was administered intramuscularly at increasing doses of 1. 5, 3, 6, 12.5 and 25 mg kg-1 which produced dose-dependent anti-inflammatory effects in the carrageenan-induced rat paw edema. The anti-inflammatory activity of nimesulide was greater than that of diclofenac which was administered at identical doses though the difference was not statistically significant. Peak anti-inflammatory effects with nimesulide were observed between 2 and 3 h post-treatment which correlates well with the tmax of 115 min. The plasma concentration of nimesulide at different time points was assayed using HPLC after administration at a dose of 25 mg kg-1. Peak plasma concentration (Cmax) was 23 microgram ml-1 while t1/2 was derived as 4.2 h. Area Under Curve (AUC(0-6 h)) was calculated as 83. 31 microgram ml-1 h-1. No toxicity or adverse effects were noted at the doses administered. The present study demonstrates that nimesulide administered intramuscularly may be superior to other routes of administration when fast onset of action is required with high plasma concentration.

Chlamydial and gonococcal serology in women with tubal infertility

Sera from 81 infertile women with tubal pathology and 40 controls were tested for the presence of antibodies against Chlamydia trachomatis & Neisserria gonorrhoeae. Indirect immunoperoxidase test (Ipazyme kit) & Enzyme linked immuno sorbent assay (ELISA kit) were used for detection of chlamydial & gonococcal antibodies respectively. Antibodies to Ch. trachomatis were found in 74.07% of the infertile women and 5% in control group. Only a very low prevalence (4.93%) of antibodies to N. gonorrhoeae was found is infertile women as compared to nil in control group. Antibodies detection is a sensitive, specific and noninvasive test for diagnosing infertility.

Suppressive effect of circulating immune complexes from leprosy patients on the lymphocyte proliferation induced by M. leprae antigens in healthy responders

The effect of circulating immune complexes, isolated in the form of polyethylene glycol (PEG) precipitates from leprosy patients, on lymphocyte proliferation was studied. The results obtained showed that PEG precipitates obtained from the borderline lepromatous/lepromatous (BL/LL) types of leprosy patients and those undergoing erythema nodosum leprosum (ENL) had significant suppressive effects on the lymphocyte proliferation induced by Mycobacterium leprae antigens in healthy responders. The percent decreases in the mean values of delta cpm in the presence of PEG precipitates from the BL/LL and ENL groups were found to be 46.8 +/- 22.4 and 65.0 +/- 24.3, respectively. However, no significant suppressive effects (except for ENL PEG precipitates) of these PEG precipitates were observed on the lymphocyte proliferation induced by tuberculin (PPD). Further, PEG precipitates alone (in the absence of M. leprae antigen) from the BL/LL and ENL groups were found to have no effect on the lymphocyte proliferation.

Antigens of Mycobacterium leprae in the cerebrospinal fluid of leprosy patients: detection by monoclonal-antibody-based sandwich immunoradiometric assay and avidin/biotin immunoblotting

Mycobacterium leprae antigens could be detected in the cerebrospinal fluid (CSF) of patients with leprosy, using a monoclonal-antibody-based sandwich immunoradiometric assay (SIRMA). Antigens of 12 kD, 35 kD and 30-40 kD were detected using ML06, ML04, and ML34 monoclonal antibodies, respectively. The 30-40-kD polysaccharide antigen, although present in larger amounts in M. leprae than the 12-kD and 35-kD protein antigens, was found in the CSF of comparatively fewer subjects. The antigen capture assay has been found sensitive to the level of nanograms. Avidin-biotin-based immunoblotting using pooled leprosy sera detected a larger number of antigens than using anti-M. leprae antisera raised in rabbits. The immunoblotting of CSF samples revealed about three antigens in the region of 100-160 kD and three more in the region of 45-60 kD as probed by leprosy sera. This study has for the first time revealed the presence of M. leprae antigens in the CSF of leprosy patients and the probable involvement of the central nervous system in leprosy.

Persistent reduced solubilization of immune complexes in lepromatous leprosy patients with reactions

It is held that immune complexes (IC) play a vital role in the pathogenesis of some of the reactions in leprosy. The complement system is known to solubilize and render IC innocuous. We have previously shown that patients undergoing lepra reactions had lowered complement-mediated IC solubilization (CMS). We, therefore, undertook a prospective study of untreated multibacillary leprosy patients and monitored their CMS levels sequentially while on therapy. In addition, the concentrations of the complement component C3d, immunoglobulins G, A and M, and circulating immune complexes (CIC) were also estimated. A total of 26 patients were included in the study and were investigated at 3-month intervals for 3 years. Thirteen of the 14 patients who did not develop reactions at all had normal CMS values, although all of them showed elevated CIC. From the inception of treatment, 10 of the 12 patients who developed lepra reactions had low CMS values which remained below normal levels even after evidence of complement activation disappeared and long after the subsidence of reaction. It is suggested that this defective CMS acts as a predisposing cause of lepra reactions.

Activation of the human complement system by phenolic glycolipid 1 of Mycobacterium leprae

The activation of the complement system by phenolic glycolipid 1 (PGL) from Mycobacterium leprae was studied. It was found that PGL consumed haemolytic complement through both the classical and the alternative pathways. This was further studied at the level of C3. Although the activation was independent of anti-PGL antibodies present in normal human serum, the addition of antibody augmented the activation of complement by PGL. The uptake of C3 through the classical pathway was enhanced predominantly by IgM antibody whereas, IgG antibody against PGL was responsible for the augmentation of the alternative pathway activation. Furthermore, it was found that both the disaccharide and trisaccharide components of PGL were able to activate the complement system.