Atypical B cells consist of subsets with distinct functional profiles

Atypical B cells are a population of activated B cells that are commonly enriched in individuals with chronic immune activation but are also part of a normal immune response to infection or vaccination. To better define the role of atypical B cells in the human adaptive immune response, we performed single-cell sequencing of transcriptomes, cell surface markers, and B cell receptors in individuals with chronic exposure to the malaria parasite Plasmodium falciparum, a condition known to lead to accumulation of circulating atypical B cells. We identified three previously uncharacterized populations of atypical B cells with distinct transcriptional and functional profiles and observed marked differences among these three subsets in their ability to produce immunoglobulin G upon T-cell-dependent activation. Our findings help explain the conflicting observations in prior studies regarding the function of atypical B cells and highlight their different roles in the adaptive immune response in chronic inflammatory conditions.

Lymphotoxin beta receptor signaling directly controls airway smooth muscle deregulation and asthmatic lung dysfunction

BACKGROUND

Dysregulation of airway smooth muscle cells (ASM) is central to the severity of asthma. Which molecules dominantly control ASM in asthma is unclear. High levels of the cytokine LIGHT (aka TNFSF14) have been linked to asthma severity and lower baseline predicted FEV1 percentage, implying that signals through its receptors might directly control ASM dysfunction.

OBJECTIVE

Our study sought to determine whether signaling via lymphotoxin beta receptor (LTβR) or herpesvirus entry mediator from LIGHT dominantly drives ASM hyperreactivity induced by allergen.

METHODS

Conditional knockout mice deficient for LTβR or herpesvirus entry mediator in smooth muscle cells were used to determine their role in ASM deregulation and airway hyperresponsiveness (AHR) in vivo. Human ASM were used to study signals induced by LTβR.

RESULTS

LTβR was strongly expressed in ASM from normal and asthmatic subjects compared to several other receptors implicated in smooth muscle deregulation. Correspondingly, conditional deletion of LTβR only in smooth muscle cells in smMHCCreLTβRfl/fl mice minimized changes in their numbers and mass as well as AHR induced by house dust mite allergen in a model of severe asthma. Intratracheal LIGHT administration independently induced ASM hypertrophy and AHR in vivo dependent on direct LTβR signals to ASM. LIGHT promoted contractility, hypertrophy, and hyperplasia of human ASM in vitro. Distinguishing LTβR from the receptors for IL-13, TNF, and IL-17, which have also been implicated in smooth muscle dysregulation, LIGHT promoted NF-κB-inducing kinase-dependent noncanonical nuclear factor kappa-light-chain enhancer of activated B cells in ASM in vitro, leading to sustained accumulation of F-actin, phosphorylation of myosin light chain kinase, and contractile activity.

CONCLUSIONS

LTβR signals directly and dominantly drive airway smooth muscle hyperresponsiveness relevant for pathogenesis of airway remodeling in severe asthma.

Utility of myxedema score as a predictor of mortality in myxedema coma

OBJECTIVE

Myxedema crisis (MC) is a rare condition. There is a dearth of data regarding the predictors of mortality in MC. Predictive scores for mortality specific to the clinical and biochemical profile of MC are still lacking.

DESIGN AND METHODS

All consecutive patients presenting with MC from September 2006 to December 2020 comprised the new cohort. Patients managed between January 1999 and August 2006 comprised the old cohort. Both cohorts were compared for the determination of secular trends. Combined analysis of both the cohorts was done for clinico-demographic profile and predictors of mortality. Myxedema score (MS) and qSOFA (Quick Sequential Organ Failure Assessment) score were evaluated in all the patients.

RESULTS

A total of forty-one patients (new cohort; n = 18 and old cohort; n = 23) were enrolled into the study. There was a female predominance (80.5%). Nearly half (51.2%) of the patients were newly diagnosed with hypothyroidism on admission. Overall mortality was 60.9%. On comparative analysis among survivors and non-survivors, female gender (OR 20.4, p value 0.018), need for mechanical ventilation (OR16.4, p value 0.009), in-hospital hypotension (OR 9.1, p value 0.020), and high qSOFA score (OR 7.1, p value 0.023) predicted mortality. MS of > 90 had significantly higher mortality (OR-11.8, p value - 0.026) while MS of > 110 had 100% mortality. There was no change in secular trends over last 20 years. There was no difference in outcome of patients receiving oral or IV levothyroxine.

CONCLUSION

Myxedema crisis is associated with high mortality despite improvement in health care services. The current study is first to elucidate the role of the MS in predicting mortality in patients with MC.

Tunable phase transitions in half-Heusler TbPtBi compound

We report various phase transitions in half-Heusler TbPtBi compound using density functional theory. Specifically, the inclusion of spin-orbit coupling (SOC) leads to the band inversion resulting in the transition from the metallic to the topological semimetallic phase. However, in the presence of SOC, there is a phase transition from the topological semimetal to the trivial semimetal when the material is subjected to compressive strain-7%. Subsequently, under the further increase of compressive strain(⩾​​-7%), we find an opening of a direct band gap at the point, driving the system from the trivial semimetallic to a semiconducting state with changes in the sequence of the bands. In the absence of SOC, only the transition from the metallic to the semiconducting phase is noticed. Under tensile strain, the TbPtBi compound maintains its phase as in the unstrained condition but with an increase in the hole pocket at the Fermi level, both in the absence and presence of SOC. These tunable phase transitions (especially as a fraction of strain) make this compound very promising for application in various quantum devices, such as highly sensitive strain gauges.

Mesenchymal Stem Cell Therapy for Patients with Post COVID ARDS on ECMO Referred for Lung Transplantation - Single Center Experience from India

Purpose

India experienced a devastating second wave of the covid 19 pandemic triggered by the delta variant, which peaked in end of April and early May 2021 with average daily new cases hitting 300,000 to 400,000 and daily death toll reaching 3000 to 3500. ECMO emerged as an option for severe post covid ARDS and was offered in many centers across India for patients who were worsening despite full ventilatory support and prone positioning. A small minority of these patients who showed no improvement despite several weeks on ECMO were referred for lung transplantation to our center. Out of the 63 ECMO pts we received for Lung Transplantation 5 patients received Mesenchymal Stem Cell (MSC) infusion over and above standard treatment after getting necessary clearance from hospital Ethics committee and consent from patients’ family

Methods

We conducted a case control study on critically ill post covid ARDS patients on ECMO referred for lung transplantation to our center. 5 patients received 2 million umbilical cord derived MSCs/kgwt infused over 30 minutes, for 3 doses on days 0, 3 and 6 and was compared to other local ECMO patients (control group; n=58). The primary outcome was safety and secondary outcome was all cause mortality.

Results

All 5 patients tolerated MSC infusions well with no side effects observed. Out of the 5 patients who received MSC infusions 3 pts (60%) recovered and were weaned off ECMO successfully. 1 pt (20%) did not improve and expired, 1 pt (20%) did not recover and underwent successful lung transplantation and was discharged home. In the ECMO control group, 15 patients (26%) recovered without transplant, 23 pts (40%) underwent successful lung transplantation and 20 pts (34%) expired.

Conclusion

MSC IV infusion is safe and well tolerated without side effects in covid ARDS pts on ECMO. The efficacy of MSC in repairing the covid destroyed lung should be further evaluated in large randomised controlled studies.

Airway Complications After Lung Transplant for Post Coronaviral Disease (COVID-19) Acute Respiratory Distress Syndrome (ARDS) Related End Stage Lung Disease: Single Centre Experience

Purpose

Severe COVID-19 ARDS related end stage lung fibrosis with irreversible changes is a newer indication for lung transplantation with acceptable survival rate. Airway complication post lung transplant is a major source of morbidity and mortality with incidence as high as 25 to 49 percent. Patients with end stage COVID-19 fibrosis are likely to be clinically deconditioned with long duration of extracorporeal oxygenator (ECMO) support, high burden of sepsis and prolonged respiratory support which may affect the airways post lung transplantation.

Methods

This is a retrospective observational study after obtaining institutional ethical clearance. We reviewed electronic medical data of patients who underwent lung transplantation for post COVID-19 ARDS related fibrosis. We evaluated the incidence and type of airway complications and the various therapeutic interventions applied for its management.

Results

Between May 2020 and September 2021 our centre performed 23 bilateral lung transplants for end stage COVID-19 ARDS related fibrosis. 22 patients were on ECMO support with mean duration of 50.9 days before transplantation. All patients underwent lung transplantation with central Veno-Arterial ECMO support with mean organ ischaemia time of 360±154 minutes. The incidence of airway complication in our study group was 56%. We observed anastomotic narrowing in 3(13%), distal airway narrowing in 4(17%) and sloughing/coating of anastomotic site in 5(22%) patients. Nonspecific inflammatory polypi around the bronchial anastomotic site were noticed in 4(17%) and mild airway anastomotic dehiscence in 2 subjects. 8(34%) patients required serial bronchoscopy and balloon dilatation; 2 among them mandated additional cautery usage. 2 cases underwent polypectomy, further 4 subjects needed bronchial stent placement. 5 (21%) recipients were discharged with Tracheostomy while rest were successfully decannulated in the ward.

Conclusion

We observed a high incidence of airway complications in post lung transplant for COVID-19 ARDS related fibrosis. Early detection, timely management and serial follow up is of paramount importance in this subset of patients.

Thermodefect voltage in graphene nanoribbon junctions

Thermoelectric junctions are often made of components of different materials characterized by distinct transport properties. Single material junctions, with the same type of charge carriers, have also been considered to investigate various classical and quantum effects on the thermoelectric properties of nanostructured materials. We here introduce the concept of defect-induced thermoelectric voltage, namely,thermodefect voltage, in graphene nanoribbon (GNR) junctions under a temperature gradient. Our thermodefect junction is formed by two GNRs with identical properties except the existence of defects in one of the nanoribbons. At room temperature the thermodefect voltage is highly sensitive to the types of defects, their locations, as well as the width and edge configurations of the GNRs. We computationally demonstrate that the thermodefect voltage can be as high as 1.7 mV K^-1for 555-777 defects in semiconducting armchair GNRs. We further investigate the Seebeck coefficient, electrical conductance, and electronic thermal conductance, and also the power factor of the individual junction components to explain the thermodefect effect. Taken together, our study presents a new pathway to enhance the thermoelectric properties of nanomaterials.

Remission in Cushing's disease is predicted by cortisol burden and its withdrawal following pituitary surgery

AIM

To ascertain the predictors of remission and relapse in patients of Cushing's disease (CD) undergoing pituitary transsphenoidal surgery (TSS).

METHODS

Patients with CD subjected to TSS over 35 years at a tertiary care center were included. Patients were grouped into remission and persistent disease at 1 year after surgery, and were further followed up for relapse. Demographic, clinical, biochemical, histological, radiological and post-operative follow-up parameters were analyzed.

RESULTS

Of the 152 patients of CD, 145 underwent TSS. Remission was achieved in 95 (65.5%) patients at 1 year. Patients in remission had shorter duration of symptoms prior to presentation (p = 0.009), more frequent presence of proximal myopathy (p = 0.038) and a tumor size of < 2.05 cm (p = 0.016) in comparison to those with persistent disease. Post-TSS, immediate post-operative 0800-h cortisol (< 159.85 nmol/L; p = 0.001), histological confirmation of tumor (p = 0.045), duration of glucocorticoid replacement (median 90 days; p = 0.001), non-visualization of tumor on MRI (p = 0.003), new-onset hypogonadism (p = 0.001), 3-month 0800-h cortisol (< 384.9 nmol/L; p = 0.001), resolution of diabetes (p = 0.001) and hypertension (p = 0.001), and recovery of hypothalamic-pituitary-adrenal axis (p = 0.018) favored remission. In logistic regression model, requirement of glucocorticoid replacement (p = 0.033), and resolution of hypertension post-TSS (p = 0.003) predicted remission. None of the parameters could predict relapse.

CONCLUSION

The study could ascertain the predictors of remission in CD. Apart from the tumor characteristics, surgical aspects and low post-operative 0800-h cortisol, the results suggest that baseline clinical parameters, longer glucocorticoid replacement, and resolution of metabolic complications post-TSS predict remission in CD. Long-term follow-up is essential to look for relapse.

Health risks from PAHs and potentially toxic elements in street dust of a coal mining area in India

Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) (Ba, Zn, Pb, Cu, Cr, Ni, As, Co) were determined in the road dusts of a coal mining area (Dhanbad, India) to assess their content and potential human health risks. Dust samples were collected from sign boards of the heavy traffic road connecting Dhanbad and Sindri. The total PAHs (∑PAHs, all values in mg/kg) content in the road dust samples varied from 3.98 to 13.1, with carcinogenic PAHs content of 14.8-34.4% of the ∑PAHs. Phenanthrene (2.72), fluorene (0.715) and pyrene (0.575) are the major PAHs. Principal component analysis revealed that these PAHs are probably originated from pyrogenic (coal combustion and traffic emission) and petrogenic (coal dust, tyre and road particles) sources. Among the PTEs, the mean content was higher for Ba (293 mg/kg) followed by Zn (224), Pb (128), Cu (52.6), Cr (45.2), Ni (22.0), As (17.5) and Co (8.11). The overall pollution load index varied from 0.43 to 1.0. Source analysis showed that PTEs in the road dust of the study site were derived from traffic emission (Zn, Fe, Mn, Co and Pb), coal dust (Cr, As and Ni) and soil (K, Mg, Ba, Sr and Ca). In general, the PTEs are lower, but the PAHs contents were elevated in the road dust samples. Although the exposure risks from PTEs are low, the risk to children (expressed as hazardous quotient) for As and Pb is near to the permissible limit of 1.0. Cancer risk from PAHs for adult (4.8 × 10^-6) and child (5.3 × 10^-6) has exceeded the acceptable limit of 10^-6.

Metamagnetic transition and observation of spin-fluctuations in the antiferromagnetic Heusler compound Pd2MnIn

We report detailed investigations on the structural, magnetic, magneto-transport and calorimetric aspects of a partially ordered Heusler compound Pd₂MnIn. The sample shows antiferomagnetic (AFM) state below around 120 K, though positive paramagnetic Curie temperature signifies a complex magnetic ground state with the presence of both ferromagnetic (FM) and AFM correlations. A clear spin-flop type metamagnetic transition is observed as evident from the magnetization and resistivity data. However, non-saturation of magnetization even at 145 kOe of applied field implies that the high field state may be a spin canted state, originating from the enhanced FM correlations by field induced conduction electron spin polarization. The sample shows a profound quadratic temperature dependence of resistivity below about 20-25 K indicating a spin-fluctuation dominated low temperature region. Previous electronic structure calculations show the existence of a subtle balance between superexchange mediated AFM state and an RKKY (Ruderman-Kittel-Kasuya-Yoshida) interaction mediated FM state in Pd₂MnIn. Such competing AFM-FM correlations can be accounted for the observed spin fluctuations.

Effect of Linagliptin on Incretin-axis and Glycaemic Variability in T1DM

BACKGROUNDS AND OBJECTIVES

Short-term studies have demonstrated potential therapeutic efficacy of dipeptidyl peptidase 4 inhibitors (DPP4 inhibitors) in patients with poorly controlled T1DM. In this study we evaluated the effect of DPP4 inhibitor, linagliptin, on glycaemic control and variability, and incretinaxis in well controlled T1DM patients to mitigate the effect of glucotoxicity on incretin secreting cells.

METHODS

Twenty T1DM patients were randomized to receive either linagliptin (10 patients, dose-5 mg/day) or placebo (10 patients), in addition to insulin for 3 months. HbA1C, continuous glucose monitoring (CGM) and mixed meal test (MMT) were performed before and at the end of the study period.

RESULTS

HbA1C reduction and change in glycaemic variability and insulin requirement in the linagliptin group did not attain the level of statistical significance. The increase in AUC GLP1 (Area under curve for GLP1) and decrease in AUC glucagon (Area under curve for glucagon) during the MMT in linagliptin group were also statistically insignificant.

INTERPRETATIONS AND CONCLUSIONS

Linagliptin is not effective in reducing HbA1C and glycaemic variability in relatively well controlled T1DM patients.

First report of Chikungunya virus circulation during a dengue outbreak in Arunachal Pradesh, a Northeastern state of India

Dengue has become a major public health problem in Pasighat, Arunachal Pradesh since 2012 outbreak. This region is rich in Aedes mosquitoes, the common vector for Dengue and Chikungunya (CHIK), however, active surveillance of CHIK is lacking in this part of India. Therefore, this study has been undertaken to detect the presence of CHIKV infection during 2014 and 2015 dengue outbreak in Arunachal Pradesh. A total of 116 (52 during 2014 and 64 during 2015 outbreak) dengue negative serum samples were collected from General Hospital, Pasighat and were screened for the presence of CHIK IgM antibodies. All the samples were further processed for CHIKV RNA detection by RT-PCR using specific primers. Phylogenetic tree was constructed by Neighbor Joining method using Kimura-2 parameter model. A total of 8 samples were found to be positive for IgM antibodies. RT-PCR showed CHIKV RNA positivity in 2 samples. Both of these samples belonged to 2014 outbreak. Phylogenetic tree revealed that the CHIKV circulating during the outbreak belonged to Eastern, Central and Southern African genotype. Sequence analysis showed two uniform nucleotide substitutions. Circulation of CHIKV masked by dengue is reported from this study. Therefore, CHIKV diagnosis should be made as a routine test in areas where dengue is already endemic so as to prevent misdiagnosis of the disease and to check its accomplishment before commencing an outbreak.

Glassy magnetic ground state and Kondo-like behaviour in Mn10FeGe8 alloy

We report a detailed investigation of the ground-state magnetic properties of newly synthesized [Formula: see text] [Formula: see text] alloy. The sample can be thought of being derived by substituting one Mn atom by Fe of the parent compound [Formula: see text] [Formula: see text]. Fe-substitution leads to a drastic change in the magnetic ground state as well as to the magneto-transport properties of the parent alloy. On cooling below 250 K, [Formula: see text] [Formula: see text] undergoes a transition from paramagnetic phase to a state having significant ferromagnetic correlations. The ground state is found to be canonical spin glass (CSG) type in nature as evident from the dc magnetization and ac susceptibility measurements. Interestingly, the resistivity data shows an upturn at low temperature below about 30 K, mimicking Kondo-like behaviour. [Formula: see text] [Formula: see text] turns out to be a rare example among 3d transition metal alloys, where a Kondo-like state coexists within a CSG phase.

Effect of Skin Application of Dorogov's Antiseptic-Stimulant on Behavioral Reactions in Rats

Local application of the Dorogov's antiseptic-stimulant onto the skin of 2-month-old male Sprague-Dawley rats in a low dose (0.5 g/kg/day) for 1 week increased motor and ultrasonic activity of experimental animals and the content of activated c-Fos⁺ neurons on the cingular, motor, insular, and pyriform cortex and in the striatum.

The inheritance of juvenile onset primary open angle glaucoma

Juvenile onset open angle glaucoma (JOAG) affects patients before 40 years of age, who present with high intraocular pressure and deep steep cupping of the optic nerve head. While it was considered to be inherited in an autosomal dominant fashion, recent studies have shown an autosomal recessive pattern as well as sporadic occurrence of the disease in several families. In this review, we analyze the genetic basis of the disease along with common mutations and their association with JOAG. We also analyzed the inheritance patterns in a large group of unrelated JOAG patients (n = 336) from Northern India wherein the prevalence of familial occurrence was assessed and segregation analysis performed, to determine the mode of inheritance.

Transport and noise properties of a normal metal-superconductor-normal metal junction with mixed singlet and chiral triplet pairings

We study transport and zero frequency shot noise properties of a normal metal-superconductor-normal metal (NSN) junction, with the superconductor having mixed singlet and chiral triplet pairings. We show that in the subgapped regime when the chiral triplet pairing amplitude dominates over that of the singlet, a resonance phenomena emerges out at zero energy where all the quantum mechanical scattering probabilities acquire a value of 0.25. At the resonance, crossed Andreev reflection mediating through such junction, acquires a zero energy peak. This reflects as a zero energy peak in the conductance as well depending on the doping concentration. We also investigate shot noise for this system and show that shot noise cross-correlation is negative in the subgapped regime when the triplet pairing dominates over the singlet one. The latter is in sharp contrast to the positive shot noise obtained when the singlet pairing is the dominating one.

The structural characterization and biological activity of sulfamethoxazolyl-azo-p-cresol, its copper(ii) complex and their theoretical studies

Sulfonamide-azophenol and its copper(ii) complex exhibit antimicrobial activity and interaction with DNA. Molecular docking was used to determine the mechanism of drug action.

Prevalence of lymphatic filariasis in a tea garden worker population of Dibrugarh (Assam), India after six rounds of mass drug administration

BACKGROUND & OBJECTIVES

Lymphatic filariasis (LF) is endemic in the state of Assam and mass drug administration (MDA) programme for LF elimination is being implemented in the state since 2004. A study on prevalence of microfilaria (mf), disease endemicity and vector infection was carried out in a tea garden population of Dibrugarh, Assam (India) to assess the effect of ongoing MDA programme on elimination of LF.

METHODS

Finger prick thick blood smears (20 mm3) were made from individuals aged ≥2 yr old during night blood survey in between 2000-0000 hrs during the period of November 2012 to February 2013. Blood smears were dehaemoglobinised, stained with Giemsa and examined under microscope for presence of mf. Indoor resting mosquitoes were collected during 0600-1000 hrs and female Culex quinquefasciatus were dissected and examined under microscope for larval forms of the parasite.

RESULTS

A total of 634 blood smears were collected and screened for mf and 47 (7.41%) individuals were found microfilaraemic, with predominance of males (74.5%). Highest mf rate (20.0%) was seen in the males of 30-39 yr age group while in females, age group of 10-19 yr recorded maximum mf rate (5.48%). Entomological collection and dissection of Cx. quinquefasciatus revealed presence of larval stages of the parasite and infection and infectivity rates recorded were 13.20 and 3.70%, respectively. Chronic clinical manifestations in the form of elephantiasis and hydrocele were recorded in 33 (5.73%) subjects of the 575 examined.

INTERPRETATION & CONCLUSION

Mass drug administration data showed six rounds of MDA with drug distribution coverage in between 63.42 and 95.93% in the study population. Out of 634 individuals examined 47 were found microfilaraemic giving an overall infection rate of 7.41%. Mosquito vector infection and infectivity rates were 13.20 and 3.70%, respectively. Presence of high mf rate, vector infectivity rate and clinical cases in the study population after six rounds of MDA warrants concerted efforts to be made for effective implementation and monitoring of MDA for success of LF elimination programme.

Genetic polymorphisms associated with sulphadoxine-pyrimethamine drug resistance among Plasmodium falciparum field isolates in malaria endemic areas of Assam

Background:

The emergence of antimalarial drug resistance malaria parasite is widespread in North eastern region of India. During January 2012-December 2013, we conducted active surveillance for detection of antifolate resistance-associated genetic polymorphisms in Plasmodium falciparum malaria parasite from different malaria endemic areas of Assam.

Materials and Methods:

A total of 281 field samples were collected from suspected malaria patients of which 106 malaria P. falciparum positive cases were detected in microscopic slide examination. A nested PCR was done for amplification of a 648 bp portion of the dhfr gene and 710 bp portion of the dhps gene.

Results:

Mutation analysis revealed existence of three different haplotypes of the P. falciparum dhfr gene of which ANRNI was highly prevalent (90%). Triple mutant haplotypes AIRNI (N51I + C59R + S108N) of the dhfr gene associated with pyrimethamine resistance were prevalent in Chirang district of Assam. Whereas, dhps mutation study revealed that triple mutant haplotype AGEAA (S436A + A437G + K540E) associated with Sulphadoxine resistance was found among 26% of P. falciparum field isolates. However, P. falciparum dhfr-dhps two locus mutation analysis showed that there were a total of nine dhfr-dhps genotypes.

Conclusion:

It was noticed that 93.62% (88/94) isolates had mutations in the sequences of both enzymes, which is an indication of prevalence of high grade of Sulphadoxine — pyrimethamine resistance in P. falciparum malaria parasites in Assam.

Microfilarial periodicity of Wuchereria bancrofti in Assam, Northeast India

BACKGROUND & OBJECTIVES

Wuchereria bancrofti has shown nocturnal periodicity in India and other endemic countries of the world except pacific regions where non-periodic or diurnal sub-periodic forms have been reported. Presence of sub-periodic form of W. bancrofti in Andaman and Nicobar Islands, India and a case report of sub- periodic form of W. bancrofti from Mysore, India provide basis for exploring the periodicity pattern of microfilaria of W. bancrofti prevalent in Assam, Northeastern region of India. State of Assam has unique geographical location as its Northeastern region shares international boundaries with Nepal, China, Bhutan, Myanmar and Bangladesh. Evolutionary association of W. bancrofti found in Assam is not known and possibility of its link with W. bancrofti form, prevalent in neighbouring countries may not be ruled out. Hence, this study was undertaken to know the microfilarial periodicity of W. bancrofti in Assam.

METHODS

Ten microfilaria positive adult male individuals having moderate to high microfilaraemia were selected. Informed written consent from each participant was obtained. The presence of microfilaria was observed at two hourly intervals over a period of 24 h using 50 μl of finger prick peripheral blood samples. Peripheral blood smears were processed, stained and examined under microscope and microfilaria counts were recorded.

RESULTS

Data collected were calculated and analyzed using modified statistical method, and the periodicity curve was prepared. Typical nocturnal periodicity was observed at a peak time of 0003 hrs with a periodicity index of 136.2.

INTERPRETATION & CONCLUSION

Analysis of the data revealed nocturnal periodicity of the W. bancrofti prevalent in the Assam with peak periodicity about one hour ahead of the other states in India. Findings will be helpful in evaluation and monitoring of ongoing MDA programme for elimination of LF in Assam.

Population genetic study of Plasmodium falciparum parasites pertaining to dhps gene sequence in malaria endemic areas of Assam

Plasmodium falciparum malaria parasite had developed resistance to almost all the currently used antimalarial drugs. The purpose of the study was to come across the genetic distances in P. falciparum dhps gene sequences circulating in Assam. A partial fragment of P. falciparum dhps gene containing major single nucleotide polymorphisms associated with sulphadoxine resistance were amplified and sequenced. Thereafter specific bioinformatics tools like BioEdit v7.0.9, ClustalW in Mega 5, DnaSP version v.5.10.01 etc were used for the analysis. A total of 100 P. falciparum positive cases in different malaria endemic areas of Assam were included for the study. Based upon the mutation analysis, a total of seven different P. falciparum dhps genotypes were observed with five variable sites. Maximum five haplotypes were found in the P. falciparum isolates from Jorhat district of Assam. Four polymorphic sites were observed in the P. falciparum dhps gene sequences in Karbi Anglong, NC Hills, Chirang and Jorhat whereas the isolates from other study areas had three polymorphic sites. A statistically significant positive value of Tajima's D were observed among the P. falciparum field isolates in Assam indicating that there is an excess of intermediate frequency alleles and can result from population bottlenecks, structure and/or balancing selection. Extensive gene flow took place among the P. falciparum population of Jorhat with Sivasagar, Chirang with Sivasagar and Chirang with Karbi Anglong. However, large genetic differentiation was observed among the P. falciparum isolates of NC Hills with Lakhimpur, Tinsukia, Dibrugarh and Golaghat and also the parasite population of Karbi Anglong with Lakhimpur and Tinsukia signifying little gene flow among the population. This finding has shown that mutant Pfdhps gene associated with sulphadoxine resistance is circulating in Assam. It is believed that, the parasite population may have undergone high level of breeding.

The crystal structure of sulfamethoxazole, interaction with DNA, DFT calculation, and molecular docking studies

Sulfamethoxazole (SMX) [4-amino-N-(5-methyl-1,2-oxazol-3-yl)benzenesulfonamide] is structurally established by single crystal X-ray diffraction measurement. The crystal packing shows H-bonded 2D polymer through N(7)-H(7A)-O(2), N(7)-H(7B)-O(3), N(1)-H(1)-N(2), C(5)-H(5)-O(3)-S(1) and N(7)-(H7A)-O(2)-S(1). Density Functional Theory (DFT) and Time Dependent-DFT (TD-DFT) computations of optimized structure of SMX determine the electronic structure and has explained the electronic spectral transitions. The interaction of SMX with CT-DNA has been studied by absorption spectroscopy and the binding constant (Kb) is 4.37×10(4)M(-1). The in silico test of SMX with DHPS from Escherichia coli and Streptococcus pneumoniae helps to understand drug metabolism and accounts the drug-molecule interactions. The molecular docking of SMX-DNA also helps to predict the interaction feature.