Biosensing using antibody-modulated motility of actin filaments on myosin-coated surfaces

Motor proteins, such as myosin and kinesin, are biological molecular motors involved in force generation and intracellular transport within living cells. The characteristics of molecular motors, i.e., their motility over long distances, their capacity of transporting cargoes, and their very efficient energy consumption, recommend them as potential operational elements of a new class of dynamic nano-devices, with potential applications in biosensing, analyte concentrators, and biocomputation. A possible design of a biosensor based on protein molecular motor comprises a surface with immobilized motors propelling cytoskeletal filaments, which are decorated with antibodies, presented as side-branches. Upon biomolecular recognition of these branches by secondary antibodies, the 'extensions' on the cytoskeletal filaments can achieve considerable lengths (longer than several diameters of the cytoskeletal filament carrier), thus geometrically impairing or halting motility. Because the filaments are several micrometers long, this sensing mechanism converts an event in the nanometer range, i.e., antibody-antigen sizes, into an event in the micrometer range: the visualization of the halting of motility of microns-long cytoskeletal filaments. Here we demonstrate the proof of concept of a sensing system comprising heavy-mero-myosin immobilized on surfaces propelling actin filaments decorated with actin antibodies, whose movement is halted upon the recognition with secondary anti-actin antibodies. Because antibodies to the actin-myosin system are involved in several rare diseases, the first possible application for such a device may be their prognosis and diagnosis. The results also provide insights into guidelines for designing highly sensitive and very fast biosensors powered by motor proteins.

Pre-sensitization with tuberculosis and non-tuberculosis mycobacteria and its impact on TB incidence in different age groups: Chengalpattu BCG trial revisited

Individuals pre-sensitized with Mycobacterium tuberculosis (MTB), non-tuberculosis mycobacteria, and its impact on TB incidence are relatively unexplored in a high TB burden setting. We conducted secondary data analysis of a double-blind, randomized Chengalpattu BCG trial, India. Induration to Purified Protein Derivative (PPD)-S and PPD-B were proxies for exposures to MTB and M. intracellulare respectively. Optimum cut-off for PPD-S and B were determined using Receiver-Operating Characteristic curves and induration ≥12 mm for PPD-S and ≥10 mm for PPD-B were considered strong reaction. Incidence rates of culture positive pulmonary TB per 100,000 person-years (PY) were calculated. Of 270,043 individuals with skin test results, children <14 years (n = 109,383, 64% showed strong-reaction to PPD-B and 17% to PPD-S) and adults between 25 and 34 years (n = 40,292, 98% were strong reactors to PPD-B and 73% to PPD-S). Overall incidence rate was lower in individuals with PPD-S < PPD-B (136, 95% CI: 130-141/100,000 PY) compared to individuals with PPD-S > PPD-B (447, 95% CI: 427-468/100,000 PY). Incidence rates of culture positive pulmonary TB was affected by early age of exposure to cross-reactive mycobacterial antigens represented by PPD-B and exposure to MTB represented by PPD-S during adolescence and early adulthood.

Ru-W modified graphitic carbon nitride by a monomer complexation synthesis approach from a tailored polyoxometalate: towards electrochemical detection of hydrogen peroxide released by cells

Detection of hydrogen peroxide (H₂O₂) from cell cultures is important for monitoring different diseases. Here, g-C₃N₄ (gCN) was incorporated into well-defined clusters of RuW (RuW-gCN) through monomer complexation of Ru-substituted phosphotungstate and melamine for electrochemical detection of H₂O₂. RuW-gCN exhibited enhanced electrochemical sensing properties in comparison to its constituents due to the synergic effects between RuW and gCN. The characterization of RuW-gCN revealed successful complexation to form the composite in addition to the presence of a layered structure of gCN. The electrochemical sensor made of RuW-gCN was able to detect H₂O₂ with a detection limit of 46 nM in the linear ranges from 100 nM to 50 μM and from 50 μM to 1 mM. The developed sensor was employed for the selective detection of H₂O₂ in the presence of analytes like ascorbic acid (AA), dopamine, and glucose in addition to being stable even after a week of storage at room temperature. It has also been verified for real sample application by detecting H₂O₂ produced by cancer cells as a result of an AA trigger.

Estimating the Frequency of Hanifin and Rajka’s Minor Criteria among Paediatric Atopic Cases at a Tertiary Care Hospital in Western Tamil Nadu, India- A Cross-sectional Study

Introduction: Atopic Dermatitis (AD) is a common relapsing inflammatory disorder, among the paediatric population clinically, characterised by pruritus and recurring eczematous skin lesions and a host of other cutaneous changes. Diagnosis is done on the basis of clinical findings with the usage of Hanifin and Rajka’s criteria which includes 4 major and 23 minor criteria. Geographical, climatic factors and other population factors have been reported to influence the occurrence of minor criteria. Aim: To estimate the frequency of Minor criteria among paediatric atopic dermatitis in Western Tamil Nadu, India. Materials and Methods: This cross-sectional observational study was done by including 110 atopic children attending Paediatric and Dermatology Outpatient Departments (OPD) of KMCH IHSR, Coimbatore, Western Tamil Nadu, India, between March 2022 to August 2022. The clinical and ophthalmological findings were documented. Categorical variables were presented as frequency and percentages, Continuous variables were presented as Mean±Standard deviation. The data was entered in excel and was analysed using statistical package for social sciences (SPSS) version 27. Results: Among the total study population of 110, 53 (48.2%) were males and the rest 57 (51.8%) were females. The mean age was 24.73±5.18 years with a range of 2-15 years. Early age of onset was seen in 73.6% of study population. Hyperlinear palms were found in 70% of the study patients. 68.2% had Dennie Morgan infraorbital fold, 64.5% had xerosis, 61% had pityriasis alba and 60% had a family history of atopy. Conclusion: Certain minor manifestations of AD like xerosis, icthyosis, hyprerlinear palms, and perifollicular accentuation were more common in the present study. Western Tamil Nadu having a tropical semi-arid climate tempered by higher altitude could explain the differences noted in the frequency of certain minor criteria.

A New Frontier in Temporal Bone Imaging: Photon-Counting Detector CT Demonstrates Superior Visualization of Critical Anatomic Structures at Reduced Radiation Dose

BACKGROUND AND PURPOSE

Photon-counting detector CT is a new technology with a limiting spatial resolution of ≤150 μm. In vivo comparisons between photon-counting detector CT and conventional energy-integrating detector CT are needed to determine the clinical impact of photon counting-detector CT in temporal bone imaging.

MATERIALS AND METHODS

Prospectively recruited patients underwent temporal bone CT examinations on an investigational photon-counting detector CT system after clinically indicated temporal bone energy-integrating detector CT. Photon-counting detector CT images were obtained at an average 31% lower dose compared with those obtained on the energy-integrating detector CT scanner. Reconstructed images were evaluated in axial, coronal, and Pöschl planes using the smallest available section thickness on each system (0.4 mm on energy-integrating detector CT; 0.2 mm on photon-counting detector CT). Two blinded neuroradiologists compared images side-by-side and scored them using a 5-point Likert scale. A post hoc reassignment of readers' scores was performed so that the scores reflected photon-counting detector CT performance relative to energy-integrating detector CT.

RESULTS

Thirteen patients were enrolled, resulting in 26 image sets (left and right sides). The average patient age was 63.6 [SD, 13.4] years; 7 were women. Images from the photon-counting detector CT scanner were significantly preferred by the readers in all reconstructed planes (P < .001). Photon-counting detector CT was rated superior for the evaluation of all individual anatomic structures, with the oval window (4.79) and incudostapedial joint (4.75) receiving the highest scores on a Likert scale of 1-5.

CONCLUSIONS

Temporal bone CT images obtained on a photon-counting detector CT scanner were rated as having superior spatial resolution and better critical structure visualization than those obtained on a conventional energy-integrating detector scanner, even with a substantial dose reduction.

Occupational Performance Coaching for Mothers of Children with Disabilities in India

BACKGROUND.

Occupational Performance Coaching (OPC) aims to help mothers plan and manage theirs and their children's occupational performance.

PURPOSE.

To assess the effectiveness of OPC in improving occupational performance and parenting competence of mothers of children with disabilities in an Indian context.

METHOD.

Mixed method design was used. Thirty-six mothers were assigned to intervention or control groups. Occupational performance and parenting competence were measured at three time points. Semi-structured interviews were used.

FINDINGS.

OPC had significant effects on children's occupational performance (p < 0.001), mothers' occupational performance (p < 0.001), and self-competence (p = 0.003). There was also a significant difference between control and intervention groups in occupational performance (p = 0.001) and satisfaction (p = 0.003). Interviews revealed three themes: acceptance, self-learning, and challenges during OPC.

IMPLICATIONS.

OPC is effective in improving the occupational performance and parenting competence of mothers of children with disabilities in varied cultural contexts.

TB diagnostic cascade among patients registered under the Revised National TB Control Programme in Chennai, South India

OBJECTIVE

To discern and quantify the TB diagnostic cascade among patients registered under the Revised National TB Control Programme, Chennai city, Tamil Nadu, South India.

METHODS

This cross-sectional study was conducted in metropolitan Chennai from February 2017 to March 2018. We interviewed TB patients retrospectively on their diagnostic attempt in different health facilities.

RESULTS

Of 455 TB patients, only 4.4% received their diagnosis at their first health facility. Of 1250 visits to health facilities, the vast majority (79.4 vs. 20.6%) was in the public rather than the private sector. 56% of patients went to a public facility as the first point of care, of whom 1.6% shifted to private facilities subsequently. The remaining 54.4% shifted between up to five government health facilities. Male patients and those with a higher family income were more likely to shift from private to public.

CONCLUSION

Most shifts between diagnostic facilities occurred in the public sector. This necessitates interventions at public health facilities for strengthening and extending services to TB patients at their first point of care.

Analysis of phthalate esters in two different baby care products available in United Arab Emirates

Phthalates are used as plasticizers in a wide range of products and are known to affect the human health adversely. Hence, the present study was carried out to identify and quantify the presence of four phthalates namely dimethyl phthalate (DMP), dibutyl phthalate (DBP), and diethyl phthalate (DEP), di (2-ethylhexyl) phthalate (DEHP) in the two baby products i.e. baby oils and baby lotions. The daily exposure levels and hazard index of each phthalate were also calculated. It was an analytical study where two different brands of samples of baby oil and baby lotion each, from the date of manufacturing of 3, 10, and 20 months were collected. The extraction of phthalates from different samples was done and analyzed using HPTLC. Results showed the presence of all four phthalates, although some phthalates were not present in 3 M samples. The maximum concentration of all the phthalates was found in 20 M samples. Their concentration increased with the storage time indicating the possibility of leaching and migration of phthalates from the container into the product. The hazard indices for phthalates estimated for baby oil and baby lotion were found below 1, which denotes that the daily phthalate exposures are within the regulatory limits. It is important to consider that the exposure to phthalates can occur not only by dermal contact of these baby products but also through other routes. Hence, the study signifies the importance of phthalates concentration in such regularly used products.

Uncertainties in the 2004 Sumatra-Andaman source through nonlinear stochastic inversion of tsunami waves

Numerical inversions for earthquake source parameters from tsunami wave data usually incorporate subjective elements to stabilize the search. In addition, noisy and possibly insufficient data result in instability and non-uniqueness in most deterministic inversions, which are barely acknowledged. Here, we employ the satellite altimetry data for the 2004 Sumatra–Andaman tsunami event to invert the source parameters. We also include kinematic parameters that improve the description of tsunami generation and propagation, especially near the source. Using a finite fault model that represents the extent of rupture and the geometry of the trench, we perform a new type of nonlinear joint inversion of the slips, rupture velocities and rise times with minimal a priori constraints. Despite persistently good waveform fits, large uncertainties in the joint parameter distribution constitute a remarkable feature of the inversion. These uncertainties suggest that objective inversion strategies should incorporate more sophisticated physical models of seabed deformation in order to significantly improve the performance of early warning systems.

Chest radiographic manifestations of scrub typhus

Background and Rationale:

Respiratory system involvement in scrub typhus is seen in 20–72% of patients. In endemic areas, good understanding and familiarity with the various radiologic findings of scrub typhus are essential in identifying pulmonary complications.

Materials and Methods:

Patients admitted to a tertiary care center with scrub typhus between October 2012 and September 2013 and had a chest X ray done were included in the analysis. Details and radiographic findings were noted and factors associated with abnormal X-rays were analyzed.

Results:

The study cohort contained 398 patients. Common presenting complaints included fever (100%), generalized myalgia (83%), headache (65%), dyspnea (54%), cough (24.3%), and altered sensorium (14%). Almost half of the patients (49.4%) had normal chest radiographs. Common radiological pulmonary abnormalities included pleural effusion (14.6%), acute respiratory distress syndrome (14%), airspace opacity (10.5%), reticulonodular opacities (10.3%), peribronchial thickening (5.8%), and pulmonary edema (2%). Cardiomegaly was noted in 3.5% of patients. Breathlessness, presence of an eschar, platelet counts of <20,000 cells/cumm, and total serum bilirubin >2 mg/dL had the highest odds of having an abnormal chest radiograph. Patients with an abnormal chest X-ray had a higher requirement of noninvasive ventilation (odds ratio [OR]: 13.98; 95% confidence interval CI: 5.89–33.16), invasive ventilation (OR: 18.07; 95% CI: 6.42–50.88), inotropes (OR: 8.76; 95% CI: 4.35–17.62), higher involvement of other organ systems, longer duration of hospital stay (3.18 ± 3 vs. 7.27 ± 5.58 days; P < 0.001), and higher mortality (OR: 4.63; 95% CI: 1.54–13.85).

Conclusion:

Almost half of the patients with scrub typhus have abnormal chest radiographs. Chest radiography should be included as part of basic evaluation at presentation in patients with scrub typhus, especially in those with breathlessness, eschar, jaundice, and severe thrombocytopenia.

Hospital based surveillance and genetic characterization of rotavirus strains in children (<5 years) with acute gastroenteritis in Kolkata, India, revealed resurgence of G9 and G2 genotypes during 2011-2013

INTRODUCTION

India accounts for an estimated 457,000-884,000 hospitalizations and 2 million outpatient visits for diarrhea. In spite of the huge burden of rotavirus (RV) disease, RV vaccines have not been introduced in national immunization programme of India. Therefore, continuous surveillance for prevalence and monitoring of the circulating genotypes is needed to assess the disease burden prior to introduction of vaccines in this region.

METHODS

During January 2011 through December 2013, 830 and 1000 stool samples were collected from hospitalized and out-patient department (OPD) patients, respectively, in two hospitals in Kolkata, Eastern India. After primary screening, the G-P typing was done by multiplex semi-nested PCR using type specific primers followed by sequencing. Phylogenetic analysis for the VP7 gene of 25 representative strains was done.

RESULTS

Among hospitalized and OPD patients, 53.4% and 47.5% cases were positive for rotaviruses, respectively. Unlike previous studies where G1 was predominant, in hospitalized cases G9 rotavirus strains were most prevalent (40%), followed by G2 (39.6%) whereas G1 and G12 occurred at 16.4% and 5.6% frequency. In OPD cases, the most prevalent strain was G2 (40.3%), followed by G1, G9 and G12 at 25.5%, 22.8%, 9.3%, respectively. Phylogenetically the G1, G2 and G9 strains from Kolkata did not cluster with corresponding genotypes of Rotarix, RotaTeq and Rotavac (116E) vaccine strains.

CONCLUSION

The study highlights the high prevalence of RV in children with gastroenteritis in Kolkata. The circulating genotypes have changed over the time with predominance of G9 and G2 strains during 2011-2013. The current G2, G9 and G1 Kolkata strains shared low amino acid homologies with current vaccine strains. Although there is substantial evidence for cross protection of vaccines against a variety of strains, still the strain variation should be monitored post vaccine introduction to determine if it has any impact on vaccine effectiveness.

Comparison between Single Dose Azithromycin and Six Doses, 3 Day Norfloxacin for Treatment of Cholera in Adult

AIM

To evaluate the efficacy of single dose Azithromycin (1 gram) in treatment of cholera in adults. A randomized, controlled clinical trial on 120 adults with acute watery diarrhoea and moderate to severe dehydration compared the efficacy of azithromycin (1 gram) single dose and Norfloxacin (400 mg) twice daily for three days in treating cholera. Data were analysed for 64 patients who were stool culture positive for Vibrio cholerae. In conjunction with rehydration therapy, 32 patients received Azithromycin and 32 patients received Norfloxacin. Patients in the two treatment groups had comparable clinical characteristics on admission.

CONCLUSIONS

Result shows Azithromycin and Norfloxacin has got almost similar efficacy in reducing stool output, duration of diarrhoea and fluid requirement in cholera positive cases.

Evaluation of metformin hydrochloride in Wistar rats by FTIR-ATR spectroscopy: A convenient tool in the clinical study of diabetes

Introduction:

The IR absorption patterns (in cm⁻¹) provide the basis to distinguish among the constituents and to separately quantify as well as qualify them and they possess many advantages such as very small sample volume requirement, good precision over entire physiological range, avoid of costly disposables, wealth of information from a single spectral measurement. The efficacy of anti-diabetic drug metformin hydrochloride as used to treat diabetic-induced Wistar rats and their sera were analyzed by FT-IR (ATR) in absorption mode.

Materials and Methods:

The present work was attempted in the study of normal and antidiabetic regimen-treated rat blood samples using FTIR spectroscopy by the attenuated total reflectance (ATR) sampling technique. The biomolecule characteristics were measured as intensity ratio parameter (IRP) values and interpreted.

Results:

To quantify the results three IRPs such as R1, R2 and R3 were calculated, respectively, for lipid, protein, and glucose. The glucose IRP value R3 showed, 0.3802, 0.3304, and 0.2847, respectively, for diseased, metformin-treated, and normal rats.

Conclusion:

The IRP values for glucose are compared to the glucose level obtained by using a glucometer. This study can be conveniently used in diagnostic procedures, patient compliance assessment, and efficacy evaluation of metformin hydrochlorides.

Encouraging an environment to nurture lifelong learning: an Asian experience

INTRODUCTION

Within an Asian context, this study examines the effect of changing from traditional course grades to a distinction/pass/fail (D/P/F) grading system on medical student self-perceived stress levels and on student exam performance.

METHODS

At the end of the 2010-2011 academic year, the Perceived Stress Scale-10 (PSS-10) was administered to the cohort of students finishing their first year of medical studies. For the academic year 2011-2012, the grading system was changed to D/P/F for the first year of medical school. The PSS-10 was also administered to the subsequent cohort of first-year medical students at the same point in the academic year as previous. Qualitative comments were collected for both cohorts.

RESULTS

Stress as measured by the PSS-10 was significantly lower in the cohort that went through the year with the D/P/F grading system in place. Thematic analysis of qualitative responses showed a shift in sources of student stress away from peer-competition. There were no significant differences in overall exam performance.

DISCUSSION

Within an Asian context, switching to a D/P/F grading system can alleviate stress and peer competition without compromising knowledge. This may help foster a "learning orientation" rather than an "exam orientation," and contribute to inculcating lifelong learning skills.

Vibrio cholerae non-O1, non-O139 serogroups and cholera-like diarrhea, Kolkata, India

We identified 281 Vibrio cholerae non-O1, non-O139 strains from patients with diarrhea in Kolkata, India. Cholera-like diarrhea was the major symptom (66.0%); some patients (20.3%) had severe dehydration. These strains lacked the ctxA gene but many had hlyA, rtxA, and rtxC genes. Pulsed-field gel electrophoresis showed no genetic link among strains.

Vibrio fluvialis in patients with diarrhea, Kolkata, India

We identified 131 strains of Vibrio fluvialis among 400 nonagglutinating Vibrio spp. isolated from patients with diarrhea in Kolkata, India. For 43 patients, V. fluvialis was the sole pathogen identified. Most strains harbored genes encoding hemolysin and metalloprotease; this finding may contribute to understanding of the pathogenicity of V. fluvialis.

Burden of respiratory tract infections among paediatric in and out-patient units during 2010-11

INTRODUCTION

Respiratory tract infections due to viral etiology were studied with an objective to identify and compare the pathogens between Hospital Indoor and Outdoor Units.

MATERIALS AND METHODS

A hospital-based cross-sectional study was conducted among children below 12 years over a period of one year. The throat and nasal swabs were collected from both the Units and screened for viral infections by real time RT-PCR technique.

RESULTS

Out of 880 samples collected, 87% and 13% were from outdoor and indoor Department with total viral positivity rate of 30% and 25% respectively. Influenza B virus (IBV) (n=126, 16%) was more prevalent in Outdoor Unit, whereas respiratory syncytial virus (RSV) (n=18, 16%) among indoor admitted cases. The multinomial logistic regression analysis revealed that both RSV and Influenza viruses were predominant in children of pre-school age groups < 5 years. In the year 2010-11, the prevalence of human metapneumovirus (HMPV) was low. The pandemic influenza A virus (pH1N1/2009) accounted for 4% (n=29) and 0.8% (n=1) cases among Outdoor and Indoor Units respectively.

CONCLUSIONS

The Outdoor Department outnumbered the Indoor Unit in terms of patient attendees and the rate of viral infections. An effective vaccination and continuous surveillance program is the need of the hour.

Validation of a new serology-based dipstick test for rapid diagnosis of typhoid fever

Currently, no reliable diagnostic test is available for typhoid fever. One serology-based dipstick test, developed indigenously, was validated in this study. Preserved sera from 336 fever patients with known culture results for Salmonella Typhi were blindly tested by the Widal test and the new assay. Analytical sensitivities, specificities, and efficiencies for the new assay versus the Widal test were 68.8% versus 62.5%, 71.1% versus 37.1%, and 70.5% versus 43.2%, respectively (p < 0.001), considering S. Typhi-positive samples as gold standards. Thereafter, fresh sera from 102 hospital-attending children with clinical typhoid fever (including 20 confirmed nontyphoidal cases as control) were tested by both methods and analyzed statistically. The diagnostic sensitivity, specificity, and efficiency were 51.2%, 85%, and 57.8% for the new assay, and 43.9%, 65%, and 48% for the Widal test, respectively. Overall performance ability of the new assay was not better than the Widal test (p > 0.5). Further improvement of the new point-of-care typhoid assay is recommended before implementation in the field setup.

Mechanical responsiveness of the endothelial cell of Schlemm's canal: scope, variability and its potential role in controlling aqueous humour outflow

Primary open-angle glaucoma is associated with elevated intraocular pressure, which in turn is believed to result from impaired outflow of aqueous humour. Aqueous humour outflow passes mainly through the trabecular meshwork (TM) and then through pores formed in the endothelium of Schlemm's canal (SC), which experiences a basal-to-apical pressure gradient. This gradient dramatically deforms the SC endothelial cell and potentially contributes to the formation of those pores. However, mechanical properties of the SC cell are poorly defined. Using optical magnetic twisting cytometry and traction force microscopy, here we characterize the mechanical properties of primary cultures of the human SC cell, and for the first time, the scope of their changes in response to pharmacological agents that are known to modulate outflow resistance. Lysophosphatidic acid, sphingosine-1-phosphate (S1P) and thrombin caused an increase in cell stiffness by up to 200 per cent, whereas in most cell strains, exposure to latrunculin A, isoproterenol, dibutryl cyclic-AMP or Y-27632 caused a decrease in cell stiffness by up to 80 per cent, highlighting that SC cells possess a remarkably wide contractile scope. Drug responses were variable across donors. S1P, for example, caused 200 per cent stiffening in one donor strain but only 20 per cent stiffening in another. Isoproterenol caused dose-dependent softening in three donor strains but little or no response in two others, a finding mirrored by changes in traction forces and consistent with the level of expression of β(2)-adrenergic receptors. Despite donor variability, those drugs that typically increase outflow resistance systematically caused cell stiffness to increase, while in most cases, those drugs that typically decrease outflow resistance caused cell stiffness to decrease. These findings establish the endothelial cell of SC as a reactive but variable mechanical component of the aqueous humour outflow pathway. Although the mechanism and locus of increased outflow resistance remain unclear, these data suggest the SC endothelial cell to be a modulator of outflow resistance.

Genetic characteristics and changing antimicrobial resistance among Shigella spp. isolated from hospitalized diarrhoeal patients in Kolkata, India

To study the prevalence pattern and trends in the phenotypic and genetic characteristics of shigellae, we tested 212 isolates isolated from diarrhoeal patients admitted to the Infectious Diseases Hospital, Kolkata, India, from November 2007 to October 2010. Prevalence of Shigella spp. was higher in the >5 years age group (69 %) than in children in the <5 years age group (31 %). Serotypes 2a, 3a and untypable isolates of Shigella flexneri were frequently detected. An increase in the isolation of Shigella sonnei (15 %) is a novel trend in this region. Fluoroquinolone resistance among S. flexneri serotypes 2a, 3a and other serogroups of shigellae is another evolving trend. The set gene was exclusively present in S. flexneri 2a, and the sen gene was detected in all serogroups. PFGE revealed the grouping of S. flexneri isolates according to their serotypes with approximately 80-100 % similarity, whilst Shigella dysenteriae type 2 and S. sonnei were clonal in nature. There was no demarcation in the prevalence of serotypes, antimicrobial resistance or clonality between the two age groups.

Influence of relative humidity in Vibrio cholerae infection: a time series model

BACKGROUND & OBJECTIVES

Spread of cholera in West Bengal is known to be related to its ecosystem which favours Vibrio cholerae. Incidence of cholera has not been correlated with temperature, relative humidity and rainfall, which may act as favourable factors. The aim of this study was to investigate the relational impact of climate changes on cholera.

METHODS

Monthly V. cholerae infection data for of the past 13 years (1996-2008), average relative humidity (RH), temperature and rainfall in Kolkata were considered for the time series analysis of Seasonal Auto-Regressive Integrated Moving Average (SARIMA) model to investigate relational impact of climatic association of V. cholerae infection and General Linear Model (GLM) for point estimation.

RESULTS

The SARIMA (1,0,0)(0,1,1) model revealed that monthly average RH was consistently linear related to V. cholerae infection during monsoon season as well as temperature and rainfall were non-stationary, AR(1), SMA(1) and SI(1) (P<0.001) were highly significant with seasonal difference. The GLM has identified that consistent (<10%) range of RH (86.78 ± 4.13, CV=5.0, P <0.001) with moderate to highest (>7 cm) rainfall (10.1 ± 5.1, CV=50.1, P <0.001) and wide (>5-10ºC) range of temperature (29.00 ± 1.64, CV=5.6, P <0.001) collectively acted as an ideal climatic condition for V. cholerae infection. Increase of RH to 21 per cent influenced an unusual V. cholerae infection in December 2008 compared to previous years.

INTERPRETATION & CONCLUSIONS

V. cholerae infection was associated higher RH (>80%) with 29°C temperature with intermittent average (10 cm) rainfall. This model also identified periodicity and seasonal patterns of cholera in Kolkata. Heavy rainfall indirectly influenced the V. cholerae infection, whereas no correlation was found with high temperature.

Phage types of Vibrio cholerae O1 and O139 in the past decade in India

Cholera has been a prevalent disease worldwide since the early 19th century. Vibrio cholerae O1 and O139 are the two serogroups that have been mainly implicated in causing cholera. This study reports the results of biotyping, serotyping and phage typing of V. cholerae O1 and O139 (1998-2007) strains received from different parts of India for the identification of the trends in the occurrence and spread of cholera in the country. However, there has been a notable steep decline in the occurrence of V. cholerae O139 strains over the past few years resulting in no strain of V. cholerae O139 being received from any part of India in 2007 and 2008. Of the total strains received, 79.1% were serotyped as Ogawa and the remaining 20.9% were found to be Inaba, which indicates that Ogawa was the predominant serotype. Almost 100% typeability was observed with the new scheme of V. cholerae O1, with type 27 being the dominant phage type and V. cholerae O139 strains were clustered into the predominant phage type T-1. From the phage typing and serotyping results, it can be concluded that V. cholerae O1 (T-27) and O139 (T-1) strains circulate throughout the country at any given time.

Comparative evaluation of real-time PCR and conventional RT-PCR during a 2 year surveillance for influenza and respiratory syncytial virus among children with acute respiratory infections in Kolkata, India, reveals a distinct seasonality of infection

Acute respiratory tract infections (ARTIs) are one of the most common causes of morbidity and mortality in young children worldwide. Influenza virus and respiratory syncytial virus (RSV) are the predominant aetiological agents during seasonal epidemics, and thus rapid and sensitive molecular tests for screening for such agents and timely identification of epidemics are required. This study compared real-time quantitative PCR (qPCR) with conventional RT-PCR for parallel identification of influenza A virus (IAV) or influenza B virus (IBV) and RSV. A total of 1091 respiratory samples was examined from children with suspected ARTIs between January 2007 and December 2008. Of these, 275 (25.21 %) were positive for either influenza or RSV by qPCR compared with 262 (24 .01%) positive by RT-PCR. Overall, IAV, IBV and RSV were detected in 121 (11.09 %), 59 (5.41 %) and 95 (8.71 %) samples, respectively. In spite of overlapping clinical symptoms, RSV and influenza virus showed distinct seasonal peaks. IAV correlated positively and RSV negatively with rainfall and temperature. No distinct seasonality was observed in IBV infections. This is, to the best of our knowledge, the first report of a systemic surveillance of respiratory viruses with seasonal correlation and prevalence rates from eastern India. This 2 year comparative analysis also confirmed the feasibility of using qPCR in developing countries, which will not only improve the scope for prevention of epidemics, but will also provide crucial epidemiological data from tropical regions.

Intestinal parasitism and Vibrio cholerae infection among diarrhoeal patients in Kolkata, India

In this study, we have analysed the epidemiological significance of the concurrent infections caused by Vibrio cholerae and intestinal parasites among different age groups of hospitalized diarrhoeal patients in Kolkata. A total of 3556 stool samples collected during 1996-2004 were screened for vibrios and parasites. The seasonality of V. cholerae and parasitic infections were studied in detail. The detection rates for Ascaris lumbricoides and Giardia lamblia infection were more than for the hookworm, Trichuris trichiura and Entamoeba histolytica. V. cholerae O1 was identified as the predominant serogroup among diarrhoeal patients. The highest rates for V. cholerae infection were in the 2-5 years age group and combined infection of V. cholerae and parasites was recorded among children aged between 2 and 10 years.

Detection of Genogroup I and II human picobirnaviruses showing small genomic RNA profile causing acute watery diarrhoea among children in Kolkata, India☆

Picobirnaviruses (PBVs) with bisegmented small RNA genome profile (1.75 and 1.55kbp for segment 1 and 2, respectively) were detected from 1999 to 2003 in faecal specimens of acute watery diarrhoea cases, largely children (n=20) and an adult in Kolkata, India. Varying degrees of dehydration necessitated their visit to hospital for further treatment and management of acute watery diarrhoea. PBV was associated with rotavirus (n=3) or astrovirus (n=3) and with both in one case. No co-infection with norovirus, sapovirus or adenovirus was detected in the picobirnavirus positive cases. No co-infection with parasites (Cryptosporidium spp., Giardia spp., Entamoeba spp., helminths) or bacteria (Vibrio spp., Shigella spp., Escherichia coli) was detected among the picobirnavirus positive cases. There was a single instance of co-infection with Salmonella spp. (n=1). PBVs not associated with serious diarrhoea illness and showing large genome profile (2.3-2.6 and 1.5-1.9kbp for segment 1 and 2, respectively) have earlier been reported in adult individuals and recently among children from a slum community in Kolkata, India. The short genome profile PBVs associated with acute watery diarrhoea may be another emerging diarrhoeagenic virus in Kolkata, India. Molecular characterization using reported primers PicoB25-PicoB43 for Genogroup I and PicoB23-PicoB24 for Genogroup II in RT-PCR showed the presence of Genogroup I PBVs (n=6) and Genogroup II PBVs (n=5), while some could not be amplified (n=3) with these primers. Sequence analysis of Genogroup I amplicons indicated remarkable sequence heterogeneity. After more than a decade, four PBV positives of Genogroup II were detected during this study. Phylogenetic analysis showed varying degree of genetic diversity amongst PBV strains from Kolkata and other countries.

Morphological variation, histology, histochemistry and nutrient contents of Frankia root nodules in Casuarina equisetifolia

Root nodules were collected from the existing plantation of Casuarina equisetifolia from three different agroclimatic zones of Tamil Nadu, India. Morphological variation, histology, histochemistry and nutrient contents of the nodules were studied. The nodules were found to be simple, dichotomously branched and coralloid. The stele in simple and branched nodules reached up to the tip of the nodules. Structure of Frankia nodules was described using histochemical methods to elucidate the nature of micro-symbiont within the nodules. The nodule consisted of a distinct periderm enclosing the cortex. The cortex showed patches of infected cells interspersed among the uninfected ones. Inside the cortex was a stele bound by an endodermis, which contained high amount of tannin. The micro-symbiont was observed in the nodule tisues in hyphal form and spore packed sporocorp was also seen in the cortex. The histochemical tests revealed the presence of proteins, insoluble polysaccharides and polyphenols.

Effect of aqueous bark extract of Garuga pinnata Roxb. in streptozotocin-nicotinamide induced type-II diabetes mellitus

A study was undertaken to evaluate the antihyperglycemic activity of aqueous extract of bark of Garuga pinnata Roxb. (Burseraceae). The various parameters studied included fasting blood sugar levels, serum lipid levels, liver glycogen content, serum insulin level and glycated hemoglobin in diabetic and normal rats. Streptozotocin-nicotinamide was used to induce type-II diabetes mellitus. Treatment with the extract at two dose levels showed a significant increase in the liver glycogen and serum insulin level and a significant decrease in fasting blood glucose and glycated hemoglobin levels. The total cholesterol and serum triglycerides levels were also significantly reduced and the HDL cholesterol levels were significantly increased upon treatment with the extract thus proving the potent antidiabetic property of the plant.

Histopathological changes in experimental cholera with a non toxigenic non- O1 non-O139 Vibrio cholerae strain isolated from Kolkata, India

This study was conducted to understand the pathophysiological changes in experimental rabbit ileal loop model using the Vibrio cholerae strain non-O1non-O139, isolated as sole pathogen from clinically diagnosed cholera patients in Kolkata. Significant amount of haemorrhagic fluid accumulation was observed in all the test loops of rabbit model where the strain of V.cholerae was inoculated as compared to control loops. Microscopic examination of the accumulated fluid showed the presence of erythrocytes and pus cells. Histology revealed structural alteration of the villous epithelium with inflammatory cells infiltration in all the layers of the gut mucosa including the nerve plexus region. Preliminary observation with a haemagglutinin protease extracted from the non-O1 non-O139 strain, was also studied in different concentrations in the same animal model which showed similar type of macroscopic and microscopic response in the ileal loops as seen with the original strain. The results highlight that along with other pathways, inflammatory cells and the enteric neurons have an important role in the pathophysiology of diarrhoea and the isolated protease may be the probable virulence factor in initiating the disease process in this non-O1non-O139 strain induced cholera.

Antipyretic activity of Alstonia macrophylla Wall ex A. DC: an ethnomedicine of Andaman Islands

PURPOSE

Alstonia macrophylla Wall ex A. DC. Leaf, used in different ailments by the Onge tribes of Little Andaman Island, India, was investigated for its antipyretic potential.

METHODS

The methanol extract and its fractions were tested on normal body temperature and yeast-induced pyrexia in Wistar Albino rats.

RESULTS

The leaf extract at oral doses of 200 and 300 mg/kg, and the n-butanol fractions of the extract at 50 mg/kg showed significant reduction in normal body temperature and yeast-provoked elevated temperature in a dose-dependent manner comparable to that of standard antipyretic drug paracetamol. The antipyretic effect was started at 1 h and extended for at least 5 h after the drug administration.

CONCLUSIONS

The antipyretic effect was more pronounced when the fraction A and B was administered together, indicating that both the fractions may contain antipyretic compounds which produce an additive effect in combination. Phytochemically these fractions contain beta-sitosterol and ursolic acid.

Alcoholic stem extract of Coscinium fenestratum regulates carbohydrate metabolism and improves antioxidant status in streptozotocin-nicotinamide induced diabetic rats

Alcoholic extract of the stems of Coscinium fenestratum, a medicinal plant indigenous to India and Sri Lanka used in ayurveda and siddha medicine for treating diabetes, was studied for its carbohydrate metabolism effect and antioxidant status in streptozotocin-nicotinamide induced type 2 diabetic rats. Oral administration of C. fenestratum stem extract in graded doses caused a significant increase in enzymatic antioxidants such as catalase, superoxide dismutase, glutathione synthetase, peroxidase, and glutathione peroxidase and in the nonenzymatic antioxidants ascorbic acid, ceruloplasmin and tocopherol. Effects of alcoholic extract on glycolytic enzymes such as glucose-6-phosphate dehydrogenase, lactate dehydrogenase and hexokinase showed a significant increase in their levels, whereas a significant decrease was observed in the levels of gluconeogenic enzyme, glucose-6-phosphatase and alanine aminotransferase in treated diabetic rats. Serum creatinine and urea levels also declined significantly. This investigation demonstrates significant antidiabetic activity of C. fenestratum.

Hepatitis B infection in Eastern Indian families: need for screening of adult siblings and mothers of adult index cases

OBJECTIVES

India, with its 43 million hepatitis B virus (HBV) carriers and absence of any national immunization programme, adds a substantial number of HBV infections to the HBV carrier pool yearly. The aim of this study was to assess the spread of HBV infection in families with an infected member and to identify the family members with the highest risk of infection in our community.

METHODS

A total of 937 serum samples from 215 HBV-infected cases and 722 members of their households were screened prospectively for markers of HBV by commercial enzyme-linked immunosorbent assay.

RESULTS

Among family members, 140 (19.4%) were HBsAg positive and 272 (37.6%) were negative for HBsAg but positive for either anti HBc or anti HBs. There were 145 HBsAg-positive adults among the index cases whose 133 adult siblings, 59 spouses and 59 mothers participated in the study. Interestingly, 28.81% mothers and 28.57% adult siblings of these adult index cases were positive for HBsAg compared with only 8.75% of their spouses (P < 0.001). Only 15.2% of the HBsAg-positive women in the childbearing age group were found to be HBeAg positive.

CONCLUSIONS

Our results suggest that intrafamilial childhood horizontal transmission is important for HBV transmission in our community, and highlight the need for screening of adult siblings and mothers of adult HBsAg carriers in addition to their spouses and children.

Periodic deworming with albendazole and its impact on growth status and diarrhoeal incidence among children in an urban slum of India

This study was undertaken to measure the impact of periodic deworming with albendazole on growth status and incidence of diarrhoea in children aged 2-5 years in an urban setting in India and to assess the feasibility of local health workers implementing the procedures involved. This was a double-blind, placebo-controlled, randomized, community-based intervention trial with 702 children randomly allocated to receive either albendazole or placebo. The two study groups received two doses of albendazole (400 mg) or placebo six months apart. Mean weight increased significantly in the albendazole group compared to the control group at three months, six months and nine months following treatment (P<0.01, P<0.01 and P<0.001 respectively). The albendazole group also experienced fewer episodes of diarrhoea than their control counterparts (relative risk 1.3, 95% CI 1.07-1.53) with a 28% reduction. The health workers administered the correct dosage satisfactorily and there were no adverse effects. Thus, periodic mass deworming with albendazole would seem to be a safe and effective method that could be adopted at the community level or as an integral part of school health services and could be expected to improve growth and reduce the incidence of diarrhoea in children.