Spinocerebellar ataxia type 6 in eastern India: Some new observations

Introduction:Spinocerebellar ataxias (SCAs) are hereditary, autosomal dominant progressive neurodegenerative disorders showing clinical and genetic heterogeneity. They are usually manifested clinically in the third to fifth decade of life although there is a wide variability in the age of onset. More than 36 different types of SCAs have been reported so far and about half of them are caused by pathological expansion of the trinucleotide, Cytosine Alanine Guanine (CAG) repeat. The global prevalence of SCA is 0.3-2 per 100,000 population, SCA3 being the commonest variety worldwide, accounting for 20-50 per cent of all cases, though SCA 2 is generally considered as the commonest one in India. However, SCA6 has not been addressed adequately from India though it is common in the eastern Asian countries like, Japan, Korea and Thailand.Objective:The present study was undertaken to identify the prevalence of SCA6 in the city of Kolkata and the eastern part of India.Results:6 of the 83 subjects turned out positive for SCA6, constituting therefore, 13.33% of the patient pool.Discussion:SCA6 is prevalent in the eastern part of India, though not as frequent as the other common varieties.Conclusions:Further community based studies are required in order to understand the magnitude of SCA6 in the eastern part, as well as in other regions of India.     

Direct and antibody dependent cell mediated cytotoxicity against Giardia lamblia by splenic and intestinal lymphoid cells in mice.

Direct cytotoxicity and antibody dependent cell mediated cytotoxicity against Giardia lamblia trophozoites exhibited by splenic, intraepithelial and lamina propria lymphocyte populations isolated from G lamblia infected mice were studied. Different patterns of cytotoxicity were found. Intraepithelial lymphocytes showed a direct cytotoxic activity of 20.6 +/- 5.6% before infection. It was significantly higher on the 20th (p less than 0.01) and 30th (p less than 0.05) day postinfection. Lamina propria lymphocytes showed a significantly augmented level of both direct cytotoxicity and antibody dependent cell mediated cytotoxicity on the 20th and 30th postinfection days. Direct cytotoxicity by splenic lymphocytes remained unchanged during infection but antibody dependent cell mediated cytotoxicity was significantly increased.     

Low level determinations of methyl methanesulfonate and ethyl methanesulfonate impurities in Lopinavir and Ritonavir Active pharmaceutical ingredients by LC/MS/MS using electrospray ionization

Methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) have been highlighted as potential genotoxic impurities (PGIs). A sensitive LC/MS/MS method is developed and validated for the determination of MMS and EMS impurities in both Lopinavir and Ritonavir Active pharmaceutical ingredient. Method utilizes, Atlantis T3 column with electrospray ionization in multiple reactions monitoring (MRM) mode for quantitation of impurities. The proposed method is specific, linear, accurate and precise. The calibration curves show good linearity over the concentration range of 0.01-0.23 μg/mL for MMS and 0.005-0.23 μg/mL for EMS. The correlation coefficient obtained is >0.99 in each case. Method has very low limit of detection (LOD) and quantification (LOQ). LOD and LOQ of MMS and EMS are as low as ～0.002 μg/mL and ～0.01 μg/mL respectively. Method has accuracy within 80-120% for both the analytes. This method is a good quality control tool for quantitation of MMS and EMS impurities at very low levels in Lopinavir and Ritonavir.     

Microbes responsible for acute exacerbation of COPD

This study was designed to find out the microbes responsible for acute exacerbation of chronic obstructive pulmonary disease (COPD). This study was carried out in the National Institute of Diseases of the Chest & Hospital (NIDCH), Dhaka during the period of January 2003 to December 2003. The study was a prospective case control study. There were 88 male and 2 female patients. The majority of the study subjects fell within the range of 50-70 years. All were smokers. 30 stable COPD patients were taken as control for comparison of sputum culture results of acute exacerbated COPD patients. A standard proforma with questionnaire was designed and filled to select patient with COPD. The patients were selected according to the predetermined criteria viz FEV1<70% predicted and FEV1/FVC % <70% of predicted. Morning specimen of sputum was collected after appropriate preparation and physical character of the sputum were noted. Sputum was immediately sent to microbiology lab for culture. Out of 30 stable COPD patients 6(20%) showed positive sputum culture for bacteria, Pseudomonas 3, Klebsiella 1, Streptococcus pneumoniae 1 and Haemophilus influenza 1. Majority of them were Gram-negative organism. Out of 60 patients with acute exacerbation of COPD 39 patients (65%) showed positive culture for bacteria. Pseudomonas 15, Klebsiella 8, Acinetobacter 4, Enterobacter 2, Moraxella catarrhalis 2 and mixed organisms like, Pseudomonas + Klebsiella 2 and Pseudononas + Acinobacter 1. Majority were Gram-negative bacilli viz. Pseudomonas and Klebsiella spp. species. From this study it was concluded that the prevalence of lower airway bacterial colonization in outpatients with stable COPD is high and is mainly due to Gram-negative bacilli like Pseudomonas spp. The greater rate of isolation of pathogenic bacteria in exacerbated COPD than in stable COPD in this study, supports the pathogenic role of bacteria in a proportion of acute exacerbations of chronic obstructive pulmonary disease. The organism commonly play pathogenic role in acute exacerbations of COPD are Pseudomonas and Klebsiella. Acinobacter Moraxella catarrhalis and Enterobacter also contributed in exacerbation of COPD.     

Quantitative evaluation of the relaxivity effects of iodine on GD-DTPA enhanced MR arthrography

PURPOSE: To quantify the effect of iodine on the gadolinium (Gd) contrast-enhanced signal in MR arthrography. MATERIALS AND METHODS: Saline solutions of Gd contrast agent (0-1 mmol/liter) were mixed with iodinated contrast agent (0-185 mmol/liter). The T1 and T2 relaxation constants of these solutions were measured at 1.5T. Different types of commonly used iodinated contrast agents as well as sodium iodide (NaI) solutions were also analyzed. RESULTS: Iodine caused significant T2 shortening and some T1 shortening in Gd contrast solutions. Both contrast agents independently obeyed the standard relaxation relation, and their mixture obeyed a modified version of this relation. The side chains in various iodine molecules and their viscosities affected the relaxation properties differently. For various spin-echo (SE) sequences, the signal from synovial fluid containing different concentrations of the two contrast agents was calculated. The T2-weighted signal appeared to be most affected by the increase in iodine concentrations. In the absence of Gd contrast, all SE sequences showed an initial increase in signal from iodine contrast. CONCLUSION: A generalized relation for the relaxivities of Gd contrast in the presence of iodine was established. The side chains of iodine contrast were found to alter the relaxivities of Gd contrast. Imaging with proton density (PD)-weighted SE with only iodine contrast agent was found to be feasible.     

Skoura – a genetic island for congenital insensitivity to pain and anhidrosis among Moroccan Jews, as determined by a novel mutation in the NTRK1 gene

Congenital insensitivity to pain with anhidrosis (CIPA) or hereditary sensory and autonomic neuropathy type IV is a rare, autosomal recessive neurologic disorder, characterized by absence of reaction to painful stimuli, mental retardation, self- mutilating behavior, anhidrosis, and recurrent episodes of hyperthermia. Mutations in the neurotrophic tyrosine kinase receptor 1, a receptor phosphorylated by nerve growth factor, have been documented in diverse ethnic groups. We identified the same novel nonsense mutation in two unrelated families of Moroccan Jewish descent, each with two affected siblings. This possible founder mutation may trace to the rural Jewish village in southern Morocco from where both these families originated. Genetic screening for the causative mutation among 300 unrelated Moroccan Jews did not reveal carriers for the causative mutation, thus excluding high risk for CIPA in this ethnic subpopulation.     

De novo discovery of serotonin N-acetyltransferase inhibitors

Serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase, AANAT) is a member of the GCN5 N-acetyltransferase (GNAT) superfamily and catalyzes the penultimate step in the biosynthesis of melatonin; a large daily rhythm in AANAT activity drives the daily rhythm in circulating melatonin. We have used a structure-based computational approach to identify the first druglike and selective inhibitors of AANAT. Approximately 1.2 million compounds were virtually screened by 3D high-throughput docking into the active site of X-ray structures for AANAT, and in total 241 compounds were tested as inhibitors. One compound class, containing a rhodanine scaffold, exhibited low micromolar competitive inhibition against acetyl-CoA (AcCoA) and proved to be effective in blocking melatonin production in pineal cells. Compounds from this class are predicted to bind as bisubstrate inhibitors through interactions with the AcCoA and serotonin binding sites. Overall, this study demonstrates the feasibility of using virtual screening to identify small molecules that are selective inhibitors of AANAT.