A molecular approach to identification and profiling of first-line-drug-resistant mycobacteria from sputum of pulmonary tuberculosis patients

Conventional and molecular techniques were applied to detect and characterize drug resistance of mycobacteria in the sputum samples of clinically confirmed tuberculosis. The sensitivities of mycobacterium detection by ZN staining, culture, multiplex PCR, and restriction fragment length polymorphism (RFLP) were 27.7%, 19.9%, 92.9%, and 95.7%, respectively, but all were 100% specific. The conventional and multiple-allele-specific PCR (MAS-PCR) methods enabled establishment of the drug resistance in 19.3% and 86.9% cases, respectively. We demonstrated that molecular techniques have potential in the accurate diagnosis of tuberculosis.

Diagnosing leprosy: revisiting the role of the slit-skin smear with critical analysis of the applicability of polymerase chain reaction in diagnosis

BACKGROUND

Diagnosing leprosy is challenging, especially in early-stage cases, and the need for a sensitive diagnostic tool is urgent. Polymerase chain reaction (PCR) holds promise as a simple and sensitive diagnostic tool, but its usefulness in the Indian context requires further evaluation. Slit-skin smear (SSS) remains the conventional method of leprosy detection. Hence, this study was undertaken to evaluate and compare the diagnostic efficacy of PCR versus that of SSS.

METHODS

Punch biopsy of skin and SSS were obtained from the active margins of lesions. Cases were clinically grouped according to whether they were multibacillary (MB) or paucibacillary (PB) and classified into tuberculoid (TT), borderline tuberculoid (BT), borderline lepromatous (BL), lepromatous (LL), histoid, and indeterminate groups after clinicopathological correlation. DNA was extracted from biopsy specimens, and multiplex PCR was carried out incorporating primers intended for the amplification of a specific 372-bp fragment of a repetitive sequence of Mycobacterium leprae DNA.

RESULTS

Among 164 patients, PCR was positive in 82.3%. The sensitivity of PCR was significantly greater (P < 0.0001) than that of SSS in both the MB (85.9% vs. 59.8%) and PB (75.4% vs. 1.8%) subgroups; the difference in sensitivity in the PB subgroup is remarkable. Positivity by PCR and SSS was found in 100% of LL and histoid leprosy, but PCR had significantly greater (P < 0.0001) positivity in BT leprosy and was of definite increased value in indeterminate and TT leprosy.

CONCLUSIONS

Polymerase chain reaction had higher sensitivity compared with SSS, especially in diagnostically challenging and PB cases. Thus, the use of this costly but sensitive tool should be restricted to this subgroup, because SSS is sufficiently sensitive in the diagnosis of LL and histoid leprosy.

Development of an eco-friendly method to convert life expired composite propellant into liquid fertilizer

Large quantity of composite propellants is produced as waste due to life expiry of missiles/rejection of propellant lots during manufacturing. The environmental protection agency does not allow the hazardous materials for open burning/open detonation. Therefore, a systematic study has been carried out to develop a method for the disposal of composite propellant into liquid fertilizer without affecting the environment. In this study, propellant compositions were digested in dilute nitric acid followed by neutralization with 5M KOH solution to get precipitated out aluminium as aluminium hydroxide and finally the obtained liquid was treated with orthophosphoric acid for further neutralization. The liquid fertilizer, thus, obtained was characterized for nitrate and phosphate content using ion chromatography while ICP-AES was used for the estimation of potassium, aluminium and other noxious metallic elements such as Pb, Cd, As, Cr, Cu, Ni and Zn. The analyses data indicate that liquid fertilizer is free from aluminium and noxious metallic elements while ratio of nitrogen, phosphorous and potassium are close to the Indian NPK value.

Impact of interleukin-6 promoter polymorphism and serum interleukin-6 level on the acute inflammation and neovascularization stages of patients with Eales' disease

PURPOSE

To evaluate the role of interleukin-6 (IL-6) in the inflammatory and proliferative stages of Eales' disease (ED) and to determine the influence of IL-6-174G/C polymorphism in the IL-6 and IL-6-regulated protein expression, as well as the development of ED.

METHODS

One hundred and twenty-one patients diagnosed with ED, 223 matched healthy controls, and 16 control patients with macular holes were recruited from the eastern Indian population. Serum and vitreous levels of IL-6 and vascular endothelial growth factors (VEGF) were measured by enzyme-linked immunosorbent assay. Serum levels of high-sensitivity C-reactive protein (hsCRP) were measured by enzyme immunoassay. Subjects were genotyped for the IL-6-174G/C polymorphism (rs1800795) by a custom TaqMan single-nucleotide polymorphism (SNP) Genotyping Assays system.

RESULTS

Serum IL-6 (p<0.0001), hsCRP (p<0.0001), and VEGF (p=0.0031) levels were significantly higher in the inflammatory stage of ED than in healthy controls. Serum IL-6 also significantly correlated with hsCRP (Spearman's correlation coefficient; r=0.4992, p=0.0009), but not with VEGF in this stage in ED patients. At the proliferative stage of ED, significantly higher levels of vitreous IL-6 (p=<0.0001) and VEGF (p=<0.0001) were found compared with the vitreous of patients with macular holes. A significant correlation was observed between vitreous IL-6 and VEGF in ED patients (Spearman's correlation coefficient; r=0.5834, p=0.0087). A statistically significant association was found between the -174GG genotype (p=0.006) and occurrence of ED. Mean serum and vitreous concentrations of IL-6 were also higher in the subjects with the GG genotype than in those with the GC or CC genotype in this population.

CONCLUSIONS

IL-6 expression, regulated by the allelic distribution of -174 loci and the enhanced level of IL-6, modulates CRP and VEGF concentration depending respectively on the acute inflammatory stimulation at the initial stage and angiogenic stimulation at the advanced stage of ED.

Increased Toll-like receptor-2 expression on nonclassic CD16+ monocytes from patients with inflammatory stage of Eales' disease

PURPOSE

To identify the distribution, differential Toll-like receptor (TLR) expression, and functional contribution of monocyte subpopulations in the inflammatory stage of Eales' disease (ED).

METHODS

Peripheral blood mononuclear cells were isolated from nine patients during the inflammatory stage of ED and nine age- and sex-matched healthy controls. The expression of CD14, CD16, TLR-2, and TLR-4 on monocytes was measured by flow cytometry. The CD14⁺, CD16⁻, and CD16⁺ monocyte populations were sorted on the basis of magnetic-activated cell-sorting methodology, and levels of cytokines were measured by ELISA.

RESULTS

In ED patients, the number of circulating monocytes was significantly expanded compared with that in controls (P = 0.01), with a marked increase in the nonclassic CD16⁺ subset, which showed an activated phenotype in patients that correlated with levels of serum proinflammatory cytokines and clinical progression. A higher expression of cell surface TLR-2 (P = 0.02), but not TLR-4, was found in monocytes of patients with ED. Furthermore, TLR-2 was expressed at higher levels on CD16⁺ monocytes than on CD16⁻ monocytes in patients, whereas no significant variation was found in TLR-4 expression on different monocyte subsets. Peptidoglycan-induced TNF-α expression correlated with TLR-2 expression in monocytes isolated from controls (r = 0.85, P = 0.0061), but not in monocytes isolated from ED patients (r = 0.553, P = 0.1328).

CONCLUSIONS

These results indicate that in the pathogenesis of ED, TLR activation and increased numbers of nonclassic CD16⁺ monocytes are crucial regulators, along with the secretion of proinflammatory cytokines that perpetuate the inflammatory process in the retina.

Association of interferon-gamma, interleukin-10, and tumor necrosis factor-alpha gene polymorphisms with occurrence and severity of Eales' disease

PURPOSE

Eales' disease (ED) is an idiopathic retinal vasculitis characterized by capillary nonperfusion and neovascularization. Previous reports on ED demonstrated that T-cell-mediated immunoresponse and differential cytokine production in inflammatory and angiogenic stage seem to influence the extent and severity of this disease. Therefore, the purpose of this study is to investigate the influence of cytokine gene polymorphisms on occurrence and severity of ED.

METHODS

One hundred twenty-one patients with ED were recruited from an Eastern Indian population and compared with 223 matched healthy control subjects. Genotyping of IFN-γ, IL-10, and TNF-α were performed by amplification refractory mutation system polymerase chain reaction (ARMS-PCR).

RESULTS

A statistically significant association was found between the IL-10 -1082AA (P = 0.002), TNF-α -308AA (P = 0.0017) genotypes and the IL-10 ATA haplotype (P = 0.0123) and the occurrence of ED. In addition IL-10 -1082GG (P = 0.0005), TNF-α -308GG (P < 0.0001) genotype were found to be protective against disease occurrence. A synergistically low IL-10/high TNF-α genotype increased the risk of development (P < 0.0001) and the severity (P = 0.019) of ED.

CONCLUSIONS

These data suggest that a low IL-10-expressing and high TNF-α-expressing genotype of the host can influence the occurrence and severity of outcome of ED.

Rapid identification of mycobacterium species with the aid of multiplex polymerase chain reaction (PCR) from clinical isolates

Mycobacteria are aerobic, nonspore forming, non-motile,single-cell bacteria.Of more than 40 currently recognized species of mycobacteria, Mycobacterium tuberculosis, the causative agent of human TB is the commonest pathogen for pulmonary and extra pulmonary tuberculosis cases. The other members of the Mycobacterium tuberculosis complex (MTC) or the nontubercular mycobacterium (NTM) produces similar diseases which cannot be differentiated from tuberculosis by clinical symptoms and signs. But this differentiation is important as the chemotherapy varies widely according to the strain of mycobacterium. The burden of morbidity and mortality of tuberculosis is rapidly growing worldwide, particularly with the HIV/AIDS epidemic. The strain identification of Mycobacterium remains a cumbersome, labor intensive and expensive procedure, which requires 3 to 12 weeks of time. The conventional methods of strain identification lack proper standardization and precise diagnosis. The prime objective of this study is to overcome these problems.A multiplex PCR using 3 amplicons of 165,365, and 541 base pair target sequences was done with a total number of 165 clinical isolates of suspected Koch's patients. Strain identification was compared both by conventional methods and multiplex PCR. The results of the study show that this multiplex PCR is supposed to be less complicated, less time consuming, cost-effective and superior to the conventional methods. It is also applicable for culture negative samples where strain identification is not possible by conventional approach.

Detection of mycoplasma contamination in cell substrates using reverse transcription-PCR assays

AIMS

To assess the limit of detection (LOD) and the feasibility of 16S rRNA-based reverse transcription-PCR (RT-PCR) assays for advanced detection of mycoplasma contamination in cell substrates.

MATERIALS AND METHODS

The RT-PCR approach is based on detecting the 16S rRNA molecules that, in contrast to genomic bacterial DNA, are represented by multiple copies in mycoplasma cell. The number of 16S rRNA molecules in mycoplasma cells of five species i.e. Mycoplasma arginini, Myc. fermentans, Myc. hyorhinis, Myc. orale and Acholeplasma laidlawii, all known to be frequent cell line contaminants in industrial and research laboratories, was measured using molecular methods. The results of two independently prepared mycoplasma cultures harvested at the stationary phase of their growth showed that the 16S rRNA copy number per cell varied in the range from about 400 to 2000 copies, depending on species, but stayed close between different preparations of one species. The assessment of the LOD of the in-house 16S rRNA-based RT-PCR was performed using samples of MDCK cell culture spiked with different amounts of five aforementioned mycoplasma species. To minimize the bias in methods comparison, the LOD of the RT-PCR assay was expressed in terms of genome equivalents (GEs) and compared with that determined for highly optimized 16S rDNA-based mycoplasma testing methods previously described in scientific literature.

CONCLUSIONS

The results of the study showed that the in-house 16S rRNA-based RT-PCR assay was able to reliably detect the presence of less than one mycoplasma GE that is at least 10-fold higher of the LOD previously determined for well-optimized 16S rDNA-based assays developed and described by other researchers.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of the study showed that rapid RT-PCR methods based on the detection of bacterial 16S rRNA are able to expedite mycoplasma testing of cell cultures (1-2 days vs 28 days) and to ensure the limits of detection comparable to that of currently used culture-based mycoplasma testing methods.

Multiplex PCR technique could be an alternative approach for early detection of leprosy among close contacts--a pilot study from India

Background

Implementation of Multi drug Therapy (MDT) regimen has resulted in the decline of the total number of leprosy cases in the world. Though the prevalence rate has been declining, the incidence rate remains more or less constant and high in South East Asian countries particularly in India, Nepal, Bangladesh, Pakistan and Srilanka. Leprosy, particularly that of multibacillary type spreads silently before it is clinically detected. An early detection and treatment would help to prevent transmission in the community. Multiplex PCR (M-PCR) technique appears to be promising towards early detection among contacts of leprosy cases.

Methods

A total of 234 paucibacillary (PB) and 205 multibacillary (MB) leprosy cases were studied in a community of an endemic area of Bankura district of West Bengal (Eastern India). They were assessed by smear examination for acid-fast bacilli (AFB) and M-PCR technique. These patients were treated with Multidrug Therapy (MDT) as prescribed by WHO following detection. A total of 110 MB and 72 PB contacts were studied by performing M-PCR in their nasal swab samples.

Results

83.4% of MB patients were observed to be positive by smear examination for AFB and 89.2% by M-PCR. While 22.2% of PB patients were found to be positive by smear examination for AFB, 80.3% of these patients were positive by M-PCR. Among leprosy contacts (using M-PCR), 10.9% were found to be positive among MB contacts and 1.3% among PB contacts. Interestingly, two contacts of M-PCR positive MB cases developed leprosy during the period of two years follow up.

Conclusion

The M-PCR technique appears to be an efficient tool for early detection of leprosy cases in community based contact tracing amongst close associates of PB and MB cases. Early contact tracing using a molecular biology tool can be of great help in curbing the incidence of leprosy further.

A hospital-based study to evaluate the incidence pattern of group A streptococcal throat infections from different age group patients

Streptococcus pyogenes(group A) is a major pathogen capable of causing a wide range of diseases in different age group of people. In this study 100 patients were selected who presented with the complaint of sore throat. All the patients were divided in four age groups. Streptococcus pyogenes colonies were confirmed on the basis of beta-haemolysis, bacitracin sensitivity test, and latex agglutination test for group A. Out of a total of 100 samples, 42 were confirmed as group A streptococcus. From this study, it has been observed that all age groups, with maximum occurrence in 5-15 years age group, were suffering from group A streptococcal pharyngitis. Therefore every case of sore throat especially affecting children should be investigated to detect the causative agent for initiation of proper therapy so that the more serious outcome like acute rheumatic fever (ARF) and acute glomerulonephritis (AGN) can be prevented.

Studies on the effect of plasticiser and addition of toluene diisocyanate at different temperatures in composite propellant formulations

Different composite propellant mixtures have been prepared using ammonium perchlorate, aluminium powder and hydroxyl terminated polybutadiene by varying the percentage of plasticiser and addition of toluene diisocyanate at different temperatures, and studied their different properties such as viscosity build-up, mechanical and ballistic properties and sensitivity. The data on different plasticiser level indicate that on decreasing the plasticiser content, there is a significant enhancement in end of mix viscosity, tensile strength and modulus while elongation decreases drastically. The data on sensitivity of the studied mixtures reveal that on decreasing the percentage of plasticiser, the sensitivity increases, accordingly. Further, the data on the effect of addition of TDI at different temperatures (35-60 degrees C) infer that on increasing the addition temperature of TDI there is a decrease in end of mix viscosity i.e. 800Pas at 35 degrees C to 448Pas at 60 degrees C. Moreover, there is no effect on mechanical and ballistic properties on higher temperature addition of TDI was observed.

Adenosine deaminase estimation and multiplex polymerase chain reaction in diagnosis of extra-pulmonary tuberculosis

SETTING

Extra-pulmonary tuberculosis (EPTB), including mycobacteriosis, contributes 15-20% of all tuberculosis (TB) cases. The diagnosis of EPTB remains elusive because of the inadequate sensitivity of routine and conventional bacteriological methods for the detection of Mycobacterium tuberculosis and related organisms in clinical specimens such as cerebrospinal fluid (CSF), pleural fluid and peritoneal fluid.

OBJECTIVE

To develop a better diagnostic marker for EPTB.

DESIGN

In our study, 179 cases of EPTB were analysed for acid-fast bacilli (AFB) smear, adenosine deaminase activity (ADA) and multiplex polymerase chain reaction (PCR). Although estimation of ADA is helpful, its sensitivity and specificity varies widely. On the other hand, a multiplex PCR using amplicons such as IS6110, dnaJ gene and hsp65 genes has high sensitivity (60-88%) and specificity (81-100%).

RESULTS

On comparing AFB and ADA results with PCR, the PCR is clearly more effective than AFB (P < 0.001) and ADA estimation (P < 0.02) in CSF. The same result was observed with peritoneal fluid (P < 0.001 vs. P < 0.05) and pleural fluid (P < 0.001 and P < 0.05).

CONCLUSION

The study shows that multiplex PCR remains the best tool and is a much better marker for diagnosing EPTB.

Alteration of timing of secretion of vascular endothelial growth factors is responsible for progression of diabetic retinopathy

Diabetic retinopathy is one of the most common complications in diabetes mellitus due to persistent hyperglycaemia. Various biochemical mechanisms have been suggested to cause this complication. The authors' present study which included 100 patients of type-2 diabetes mellitus with different stages of diabetic retinopathy and without retinopathy shows that initiation of diabetic retinopathy is associated with increased anaerobic glycolysis and accelerated oxidative stress. Progression of this complication is guided by increased secretion of vascular endothelial growth factors. It is our assumption that increased secretion of vascular endothelial growth factors in early part of this disease e.g. before occurrence of morphological abnormality may modify this complication.

Development and application of a new efficient and sensitive multiplex polymerase chain reaction (PCR) in diagnosis of leprosy

India contributes about 80% of the global leprosy case load including case of fresh infection and reinfection. Due to lack of gold standard, diagnosis is done mainly based on routine clinical signs and symptoms, smear and histopathological evidences. There is a lot of lacunae in early confirmatory diagnosis in terms of sensitivity and specificity, especially in paucibacillary tuberculoid type. Moreover, the classification of different classes of leprosy is very important for selection of proper therapeutic schedule. Hence this study was undertaken to develop a multiplex polymerase chain reaction for the diagnosis and strain differentiation of M leprae. A multiplex polymerase chain reaction was developed using the primers R1 and R2 (a) amplifying 372bp DNA target from a repetitive sequence of M leprae and this repetitive sequence (372bp) that was used as a target DNA for amplification was reported to be specific for M leprae was not present in 20 mycobacterium species other than M leprae and primers TTCA and TTCB (b) amplifying (201bp) DNA target of variable sizes from the regions flanking TTC repeats of M leprae genome. This multiplex polymerase chain reacton developed in our laboratory revealed that the number of repeats at each locus might be variable among M leprae but they are found mostly in multibacillary (as the bacterial load is higher in multibacillary) type.

Waste explosives and other hazardous materials--hazard potential and remedial measures: an overview

A large amount of energetic materials including propellants, high explosives, pyrotechnics are subjected to disposal either due to expiry of their useful life or rejection in the manufacturing process. The environmental regulations do not allow the hazardous materials for open burning / detonation in view of the health hazard involved in these operations. The present paper describes the hazard potential of energetic materials and associated hazardous chemicals. It also deals with global technological status for remedial measures of hazardous chemicals along with their merits and demerits.

Studies on siderophore production of different diarrhoeagenic Escherichia coli

In the present study, siderophore production capacity of various diarrhoeagenic E coli strains was tested on quantitative basis. The collected strains were classified under enteropathogenic E coli, enterotoxigenic E coli and entero-invasive E coli groups by using appropriate techniques. A few reference . enterotoxigenic E coli strains were also included in this study. The confirmation of various properties of enteropathogenic E coli, enterotoxigenic E coli and entero-invasive E coli strains was carried out by standard procedures. Several non-pathogenic E coli strains were also included in the study to assess their siderophore producing capacity. The results presented in the study showed that, the phenolate type of siderophore, that is enterochelin was predominantly produced by majority of these E coli strains. Only 30% of enteropathogenic E coli and 33% of enterotoxigenic E coli strains failed to produce any detectable level of enterochelin. On the other hand, only 50% of enteropathogenic E coli strains and all the entro-invasive E coli (100%) showed the positive aerobactin that is hydroxamate type of siderophore production ability. None of the enterotoxigenic E coli and non-pathogenic strains produced aerobactin.

Coexistent partial anodontia and supernumerary tooth in the mandibular arch: a rare case

Coexistent partial anodontia and supernumerary tooth in the lower jaw is a very uncommon condition. Very few cases have been reported in the literature of this condition, etiology of which is still obscure. Presented here is a rare case of simultaneous presence of single supernumerary tooth together with missing permanent central incisor teeth in the lower jaw without any associated systemic condition or syndrome.

Immunogenetic association and thyroid autoantibodies in juvenile autoimmune thyroiditis in North India

OBJECTIVES

Autoimmune thyroid diseases (AITD) encompass a number of conditions that have in common cellular and humoral responses targeting the thyroid gland. Interactions between susceptibility genes and environmental triggers are thought to initiate an autoimmune response to thyroid antigens leading to disease manifestation. Commencement of the disease in childhood leads to the presumption that genetics may have an important role in the causation of the disease.

DESIGN

The present study was aimed at evaluating the human leucocyte antigen (HLA) encoded susceptibility to develop juvenile autoimmune thyroiditis (JAT) in patients from North India.

PATIENTS

We studied 48 consecutive patients of JAT along with 176 first-degree relatives for their thyroid function (FT4, TSH) and anti-thyroid peroxidase antibody status (AbTPO).

MEASUREMENTS

HLA studies were carried out using serology for HLA-class I antigens and DNA analysis of HLA-class II alleles. The data were compared with a cohort of 308 ethnically matched healthy individuals.

RESULTS

We observed overt hypothyroidism in 50% and AbTPO positivity in 70.8% of the index cases. Among the first-degree relatives, goitre was observed in 51.7%, thyroid dysfunction in 28.4% and AbTPO in 29.5% of individuals. Of the 37 relatives who underwent fine-needle aspiration cytology (FNAC), 60% had evidence of chronic lymphocytic thyroiditis (CLT). A strong positive association of HLA-DRB1*1404 was observed with the JAT (35.4%vs. 10.4%, chi2 = 19.8, Pc = 0.0001). We also observed a higher (72%, P = 0.03) paternal transmission of HLA-DRB1*1404 to affected offspring in comparison to unaffected offspring. HLA-DRB1*03 was also increased among JAT patients but did not reach statistical significance.

CONCLUSION

These studies point towards an important role of immune modifying genes, such as HLA, in influencing susceptibility to juvenile-onset AITD.

Machine learning in soil classification

In a number of engineering problems, e.g. in geotechnics, petroleum engineering, etc. intervals of measured series data (signals) are to be attributed a class maintaining the constraint of contiguity and standard classification methods could be inadequate. Classification in this case needs involvement of an expert who observes the magnitude and trends of the signals in addition to any a priori information that might be available. In this paper, an approach for automating this classification procedure is presented. Firstly, a segmentation algorithm is developed and applied to segment the measured signals. Secondly, the salient features of these segments are extracted using boundary energy method. Based on the measured data and extracted features to assign classes to the segments classifiers are built; they employ Decision Trees, ANN and Support Vector Machines. The methodology was tested in classifying sub-surface soil using measured data from Cone Penetration Testing and satisfactory results were obtained.

Machine learning in sedimentation modelling

The paper presents machine learning (ML) models that predict sedimentation in the harbour basin of the Port of Rotterdam. The important factors affecting the sedimentation process such as waves, wind, tides, surge, river discharge, etc. are studied, the corresponding time series data is analysed, missing values are estimated and the most important variables behind the process are chosen as the inputs. Two ML methods are used: MLP ANN and M5 model tree. The latter is a collection of piece-wise linear regression models, each being an expert for a particular region of the input space. The models are trained on the data collected during 1992-1998 and tested by the data of 1999-2000. The predictive accuracy of the models is found to be adequate for the potential use in the operational decision making.

Interspecific variation in heavy metal body concentrations in biota of Sunderban mangrove wetland, northeast India

The coastal environment of West Bengal, recognized as the most diversified and productive ecosystem among all the maritime states of India, faces organic pollution from domestic sewage and urban and industrial effluents leading serious impacts on biota. The present paper aims at providing information on concentration level of heavy metals among the tissues of benthic polychaetes, bivalve molluscs and finfishes collected from Sundarban mangrove wetland, northeast coast of India. An overall common trend in bioaccumulation was revealed with the following decreasing order: Zn>Mn>Cu>Cr>Se>Hg with few exceptions. Both species dependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs. Variability between closely related species is a reflection of different uptake rates, physiology and impact of environmental factors. The results of this analysis suggest that mollusks can play a significant role in trace metal trophic transfer studies, especially as their representatives are intertidally and subtidally ubiquitous.

Relation between increased anaerobic glycolysis and visual acuity in long-standing type 2 diabetes mellitus without retinopathy

In long-standing diabetes mellitus, blood flow to essential organs including the retina is reduced owing to macrovascular and/or microvascular changes. Poor glycolytic pathway of glucose metabolism owing to tissue hypoxia caused by ischemia at capillary bed of essential organs produces excessive lactic acid and less of adenosine triphosphate, which lead to poor cellular function. The purpose of the study was to evaluate the relationship between increased anaerobic glycolysis and visual acuity in type 2 diabetes mellitus without retinopathy. Fifty patients of type 2 diabetes mellitus of 10-12 years duration, without retinopathy, constituted the study group. The controls were 50 age-matched healthy persons without diabetes mellitus. Blood lactate level and best-corrected visual acuity (BCVA) were measured in both the groups. The mean blood lactate level was 1.05 mM/l in the control group and 2.32 mM/l in the study group. BCVA of 20/20 (log MAR 0) was seen in 48 (96%) patients of the control group and in 27 (54%) patients of the study group. BCVA of 20/30 (log MAR 0.2) was seen in 23 (46%) patients in the study group and 2 (4%) in the control group. Association of higher blood lactate level with decreased BCVA in the study group was statistically significant (P< 0.001).

Role of cytosolic phospholipase A2 in the enhancement of α2-adrenoceptor-mediated vasoconstriction by the thromboxane-mimetic U46619 in the porcine isolated ear artery: Comparison with vasopressin-enhanced responses

Pre-contraction with the thromboxane-mimetic U46619 enhances the subsequent alpha(2)-adrenoceptor-mediated vasoconstriction in the porcine ear artery through an enhanced activation of ERK-MAP kinase. In this study we determined the role of cPLA(2) in this enhanced response, and determined whether vasopressin is also able to enhance alpha(2)-adrenoceptor-mediated vasoconstriction through the same pathway. The cPLA(2) inhibitors AACOCF3 (50 microM) and MAFP (50 microM) both inhibited the U46619-enhanced alpha(2)-adrenoceptor response, but had no effect on the direct alpha(2)-adrenoceptor response. AACOCF3 also inhibited the enhanced ERK activation associated with the enhanced alpha(2)-adrenoceptor-mediated vasoconstriction. Pre-contraction with arachidonic acid mimicked the effect of U46619 by enhancing the contractile response to the alpha(2)-adrenoceptor agonist UK14304 (1 microM) and enhancing the alpha(2)-adrenoceptor-mediated ERK activation. Pre-contraction with vasopressin also enhanced the contractile response to UK14304, but neither PD98059 (50 microM) nor AACOCF3 (50 microM) had any effect this vasopressin-enhanced response, indicating that neither the ERK pathway, nor cPLA(2) are involved in vasopressin-enhanced responses. The alpha(2)-adrenceptor-stimulated activation of ERK was also unaffected by pre-contraction with vasopressin. On the other hand, inhibition of PKCzeta inhibited the enhanced alpha(2)-adrenoceptor contraction after pre-contraction with both U46619 and vasopressin. This study demonstrates that alpha(2)-adrenoceptor-mediated vasoconstriction can be enhanced through two different pathways-one dependent upon the enhanced activation of ERK-MAP kinase through activation of cPLA(2), and the other through a different, ERK/cPLA(2)-independent pathway.

Deep Impact: observations from a worldwide Earth-based campaign

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

Erupted maxillary conical mesiodens in deciduous dentition in a Bengali girl--a case report

Mesiodens is a midline supernumerary tooth commonly seen in the maxillary arch. It is the most significant dental anomaly affecting permanent dentition mainly and primary dentition rarely. It may occur as an isolated dental anomalous condition or may be associated with a syndrome. Many theories have been promulgated to explain its etiology. But an exact etiology is still obscure. Incidence of mesiodens in children varies from 0.15 to 3.8%. Boys are affected more (2:1) than girls. Morphologically, mesiodens may be of three types: the most commonly seen is conical, while tuberculate and supplementary types.

The efficacy of topical administration of brimonidine to reduce ischaemia in the very early stage of diabetic retinopathy in good controlled type-2 diabetes mellitus

It is now proved that diabetic micro-angiopathy is caused by ischaemia at the capillary bed of retina due to reduced capillary blood flow in long standing type-2 diabetes mellitus. Deranged metabolic process due to chronic hypoxia at the tissue level produces visual and vascular dysfunction. Brimonidine tartrate, an alpha-2 agonist which is commonly used in glaucoma to protect retinal ganglion cells from pressure related ischaemia induced cell apoptosis, is administered in very early stage of non-proliferative diabetic retinopathy to reduce ischaemia at the capillary bed of retina. Improved visual acuity and decreased micro-aneurysm formation, which indicate elimination of ischaemic stimulus at the tissue level, are seen in long standing type-2 diabetes mellitus.

The determination of n-alkanes in the cuticular wax of leaves of Ludwigia adscendens L

An n-hexane extract of fresh, mature leaves of Ludwigia adscendens, containing a thin layer of epicuticular waxes, has been analysed for the first time by TLC, IR and GC using standard hydrocarbons. The leaves contained 22 identified long chain (C15-C36) n-alkanes, accounting for 74.27% of the hydrocarbons present, and an unknown number of unidentified branched chain alkanes. The predominant n-alkane was C25 (11.02%), whilst C18 (7.62%), C20 (6.14%), C29 (5.36%) and C27 (5.29%) n-alkanes were moderately abundant: the C35 homologue was present only in minor amounts (0.22%).

Enhancement of alpha2-adrenoceptor-mediated vasoconstriction by the thromboxane-mimetic U46619 in the porcine isolated ear artery: role of the ERK-MAP kinase signal transduction cascade

1. Alpha(2)-adrenoceptor-mediated contractions in porcine blood vessels can be enhanced in the presence of the thromboxane-mimetic U46619, and forskolin. The aim of this study was to determine the role of U46619 in the enhanced contractions, and to determine whether signalling through the ERK-MAP kinase pathway is involved. 2. Responses to the alpha(2)-adrenoceptor agonist UK14304 (1 micro M) were increased from 22+/-3% of the response to 60 mM KCl to 68+/-12% (n=8, mean+/-s.e.m.) in the presence of a low concentration of U46619 (< 20% of the 60 mM KCl response). 3. Both the direct and the U46619-enhanced UK14304 responses were inhibited by 50 microM PD98059, an inhibitor of the ERK-MAP kinase pathway. UK14304-induced contractions were associated with an increase in ERK2 phosphorylation, indicating an increased activity. In the presence of U46619, there was an enhanced phosphorylation of ERK2. U46619 on its own had no effect on ERK phosphorylation. 4. Both the direct and enhanced UK14304 contractions were inhibited in the absence of extracellular calcium. These conditions also prevented the increase in ERK2 phosphorylation. This indicates a role for calcium influx in the enhanced contractions. 5. In conclusion, this study demonstrates that precontraction with the thromboxane-mimetic U46619 enhances alpha(2)-adrenoceptor-mediated vasoconstriction through the enhancement of the ERK-MAP kinase pathway, and influx of extracellular calcium.

Development of a new sensitive and efficient multiplex polymerase chain reaction (PCR) for identification and differentiation of different mycobacterial species

For early detection and species differentiation of mycobacteria, polymerase chain reaction (PCR) techniques are currently in wide use. However, individual techniques using amplification of different targets with appropriate primers still have some limitations, which have to be overcome. The ideal technique would use DNA sequences which should be present in all mycobacteria and absent in others and would be able to discriminate one species from the other, as non-tuberculous mycobacteria (NTM) are on rise in terms of frequency of detection. We developed a multiplex PCR based on amplification of 165, 365 and 541 bp target fragments of unrelated genes, hsp 65 coding for 65 kDa antigen, dnaJ gene of mycobacteria and insertion element IS 6110 of Mycobacterium tuberculosis, respectively. This multiplex PCR was tested over 5 years from 1996 to 2001 with 411 clinical specimens from suspected cases of tuberculosis and mycobacterioses and compared with standard laboratory techniques. The multiplex PCR was positive for 379 cases compared with 280 cases by standard techniques (P < 0.0001). It could distinguish between strains of the M. tuberculosis complex and NTM; the results are comparable with standard techniques. Thus the multiplex PCR can be useful in early detection, species differentiation and epidemiology.

The river Ganga of northern India: an appraisal of its geomorphic and ecological changes

The Ganga is the most important perennial river originating from Gangotri in the snow-bound Himalayas about 3,900 m above mean sea level. Gorging a distance of about 220 km in the Himalayas, it enters the plain at Hardwar and after meandering and braiding over a distance of about 2,525 km through the Indo-Gangetic plains, ultimately joins the Bay of Bengal. The course of this river has been changed due to: (i) subsurface geotectonic movement leading to change in slope of the deltaic plain and subsidence of the Bengal basin; (ii) changing pattern of water discharge with time; (iii) variations in sediment load. The environment of Ganga basin is also deteriorating with time due to severe natural episodes of periodic floods and storms as well as anthropogenic factors such as population growth, deforestation, agricultural activities, urbanisation, fertiliser and fossil fuel consumption and construction activities such as dams and bridges. All these have inconceivable adverse impacts on the health and natural regeneration capacity of the river basin. The presence of micropollutants in water and sediments of this river turns the system into being unsustainable to the biota. The present study synthesises the available information on the changes of its geological, geomorphological and ecological aspects and suggests some remedial measures to be adopted now and in future.

Role of chromium supplementation in Indians with type 2 diabetes mellitus

Type 2 diabetes mellitus is a complex metabolic disorder with adverse cardiovascular risk. The role of micronutrients has not yet been well clarified in this condition, especially in India.THE OBJECTIVES OF THIS STUDY WERE TO: (1) evaluate chromium status in Indian subjects with type 2 diabetes mellitus, (2) assess the effect of chromium picolinate (200 &mgr;g trivalent chromium twice daily) administration on glycaemic control and lipid profile in these subjects and (3) comment on the possible mechanism of any beneficial effect noted above.Fifty subjects were studied in a double blind, placebo-controlled, crossover fashion, with each treatment arm (chromium/placebo) lasting 12 weeks and 4 weeks' wash-off period in between. 50 healthy age- and sex-matched volunteers served as controls. Serum chromium level appeared to be higher in the general population in our country compared to western countries (36.5-59.5 nmol/L as compared to 2.3-40.3 nmol/L) However, the local diabetics were found to have a lower serum chromium level than the healthy controls (32.3 nmol/L against 44.7 nmol/L; p < 0.0001) and a mean increase of 3.5 nmol/L was noted after 12 weeks of chromium supplementation that was, expectedly, not seen in the placebo phase (p < 0.0001).Significant improvement in glycaemic control was noted in the chromium-treated group (DeltaFasting serum glucose = 0.44 mmol/L, p < 0.001; DeltaPost-prandial serum glucose = 1.97 mmol/L, p < 0.001; Deltaglycated hemoglobin = 0.01; p = 0.04, in comparison to placebo) This was accompanied by a significant greater fall in fasting serum insulin in the chromium-treated group, p < 0.05.The change in lipid parameters (total serum cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides) did not show significant difference between the chromium and placebo groups.Clinically significant hematological, renal or hepatic toxicity were excluded by routine hemogram, serum urea, creatinine, alanine amino transferase (ALT) and alkaline phosphatase estimations.In conclusion, chromium supplementation seems to improve glycaemic control in type 2 diabetic patients, which appears to be due to an increase in insulin action rather than stimulation of insulin secretion.

Short-term REM sleep deprivation effect on temperature rhythm of rats

Circadian rhythm of body temperature (CRT) is altered in endogenous depression and many psychiatric disorders. Even the sleep pattern is disrupted. Sleep deprivation alleviates symptoms in depression. The present study was conducted to find the role of noradrenergic innervation to the pineal gland in bringing about the effect of REM sleep deprivation (REMSD) on the CRT. Adult male Wistar rats (n = 12) divided into 2 groups were used for the study. The group I rats (n = 6) underwent superior cervical ganglionectomy and the group II rats (n = 6) were sham ganglionectomised. After recovery rats were given REMSD for 48 hours. The CRT was measured in three periods of the study i.e. basal, post operative and post REMSD. The results indicated REMSD increased the Amplitude and Mesor of the CRT in both the groups which was shortlasting and reversible thus suggesting non sympathetic mediation of the pineal in bringing about the circadian rhythm alteration due to REMSD.