Sudakshina Ghosh

Polymorphisms in CaSR and CLDN14 Genes Associated with Increased Risk of Kidney Stone Disease in Patients from the Eastern Part of India

Kidney stone disease (KSD) is a major clinical problem imposing a large burden for both healthcare and economy globally. In India, the prevalence of kidney stone disease is rapidly increasing. This study aimed to evaluate the association between genetic defects in vitamin D receptor (VDR), calcium sensing receptor (CaSR) and claudin 14 (CLDN14) genes and kidney stone disease in patients from eastern India. We enrolled 200 consecutive kidney stone patients (age 18–60 years) (cases) and their corresponding sex and age matched 200 normal individuals (controls). To identify genetic variants responsible for KSD, we performed sequence analysis of VDR, CaSR and CLDN14 genes. Four non-synonymous (rs1801725, rs1042636, rs1801726 and rs2228570), one synonymous (rs219780) and three intronic single nucleotide polymorphisms (SNPs) (rs731236, rs219777 and rs219778) were identified. Genotype and allele frequency analysis of these SNPs revealed that, rs1801725 (Ala986Ser), rs1042636 (Arg990Gly) of CaSR gene and rs219778, rs219780 (Thr229Thr) of CLDN14 gene were significantly associated with KSD. Serum calcium levels were significantly higher in subjects carrying 986Ser allele and calcium excretion was higher in subjects bearing 990Gly allele. In conclusion, rs1801725, rs1042636, rs219778 and rs219780 SNPs were associated with kidney stone risk in patients from the eastern part of India.

Xenobiotic Pathway Gene Polymorphisms Associated with Gastric Cancer in High Risk Mizo-Mongoloid Population, Northeast India

The aim of this study was to evaluate the risk of gastric cancer associated with individual or combined glutathione S‐transferases (GSTs) polymorphism and their interaction with environmental factors.

Spectrum and frequency of GJB2, GJB6 and SLC26A4 gene mutations among nonsyndromic hearing loss patients in eastern part of India

Genetically caused nonsyndromic hearing loss is highly heterogeneous. Inspite of this large heterogeneity, mutations in the genes GJB2, GJB6 and SLC26A4 are major contributors. The mutation spectrum of these genes varies among different ethnic groups. Only a handful of studies focused on the altered genetic signature of these genes in different demographic regions of India but never focused on the eastern part of the country. Our study for the first time aimed to characterize the mutation profile of these genes in hearing loss patients of West Bengal state, India. Mutations in GJB2, GJB6 and SLC26A4 genes were screened by bidirectional sequencing from 215 congenital nonsyndromic hearing loss patients. Radiological diagnosis was performed in patients with SLC26A4 mutations by temporal bone CT scan. The study revealed that 4.65% and 6.97% patients had monoallelic and biallelic GJB2 mutations respectively. Six mutations were identified, p.W24X being the most frequent one accounting for 71.05% of the mutated alleles. Mutations in GJB6 including the previously identified deletion mutation (GJB6-D13S1830) were not identified in our study. Further, no patients harbored biallelic mutations in the SLC26A4 gene or the common inner ear malformation Enlarged Vestibular Aqueduct (EVA). The mutation profile of GJB2 in our study is distinct from other parts of India, suggesting that the mutation spectrum of this gene varies with ethnicity and geographical origin. The absence of GJB6 mutations and low frequency of SLC26A4 mutations suggest that additional genetic factors may also contribute to this disease.

Relationship between Eustachian tube function and location of the perforation in chronic otitis media

Background: Eustachian tube function (ETF) has been the center of focus as a prognostic factor because of its presumed primary role in the pathogenesis of otitis media and clearance of the middle ear cavity. There is a general agreement that adequate ETF is necessary for middle ear surgery. In this study, the incidence of ET dysfunction and its patency has been evaluated in inactive mucosal variety of chronic otitis media, in relation to the types of central perforation. Materials and Methods: A cross-sectional study was done with 54 patients presenting with inactive mucosal type of chronic otitis media. All the recruited patients were first examined clinically and under microscope and then their audiological (impedance audiometry) and radiological assessment of mastoid was done. Alongside otoendoscopy, nasal endoscopy, dye test were done. In all these cases, other routine investigations were also performed. Results: Impedance audiometry offers an easy means of assessing ETF. The automatic Toynbee test can be a practical, objective and suitable method to assess ventilatory function of ET. The saccharin test is a simple, cost-effective and is valuable diagnostic tool to assess the mucociliary function of the ET. Mucociliary and ventilatory function may vary in the same patient. Saccharin test and methylene blue tests are comparable. Patients having poor saccharin test, methylene blue test, and ventilatory test are more prone to develop central perforation posterior to the handle of the malleus. The most frequent abnormal finding at nasal endoscopy was edema about the tubal orifice. Conclusion: A clinically useful test for ETF is still lacking. Impedance audiometry offers an easy means of assessing ETF. Ventilatory function of ET which is the single most important contributory factor in the pathogenesis of chronic otitis media should be evaluated with the objective method before tympanoplasty.

DNA Barcoding: A Tool to Assess and Conserve Marine Biodiversity

Accurate Species diagnosis is the key element for biodiversity studies and conservation planning. Conventionally, morphological characters are used to identify a species. But, this approach needs a thorough expertise in identifying the external features which often leads to narrowing down of specialization with regard to ascertaining a species within a limited group of taxa. The approach may be particularly valuable for species identification of organisms that are rare, fragile, and/or small, especially when morphological identification is problematic and errors are likely due to simple or evolutionarily conserved body plans. However, each time a new technique has been introduced in science it was accompanied by some debate and distress, and DNA barcoding was no exception. Therefore, more collaborative efforts are needed to explore the potentialities of DNA barcoding in proper species identification across all taxa. At the same time, we need to set a threshold of the genetic variation in species delimitation to find out the cryptic species. It is also an important point to know that the benefits of DNA barcoding are not restricted to taxonomic or systematic research only. The discovery of high-throughput sequencing technologies are going to change the dimension of these techniques in the years to come.