MicroRNAs in platelet physiology and pathology.

MicroRNAs (miRNAs), highly conserved, short (approx. 22 nucleotides) non-coding RNAs, exhibit a fine-tune control over gene expression by complementary sequence binding and translational repression of protein coding mRNA transcripts. Recently, the role of miRNAs has been increasingly investigated in various physiological or pathophysiological events. Circulating platelets are crucial for coagulation physiology to maintain haemostatic balance and are involved in various pathologies such as atherosclerosis and thrombosis. Anucleate platelets lack genomic DNA but inherit diverse array of functional coding or non-coding RNAs and translational machinery from their parent cells - megakaryocytes enabling activated platelets to synthesize proteins which suggests the possibility of post transcriptional gene regulation in platelets. Expression of functionally active miRNAs in platelets changes during platelet activation indicating a role in platelet biology. Here, we present a review on recently identified platelet miRNAs and their role in platelet physiology that is essential for maintaining haemostasis.

Novel techniques and targets in cardiovascular microRNA research.

MicroRNAs (miRNAs) are highly conserved, tiny (∼22 nucleotides) non-coding RNAs that have emerged as potent regulators of mRNA translation. miRNAs exhibit fine-tuning of the control of proteins involved in cell signalling (AE) pathways and in vital cellular and developmental processes. miRNAs are expressed in cardiovascular tissues, and multiple functional aspects of miRNAs underscore their key role in cardiovascular (patho)physiology. The development and increasing use of novel molecular biology tools have contributed to the recent success in miRNA research. In the present review, we discuss current updates on important and novel miRNA techniques, including: (i) miRNA screening tools; (ii) bioanalytical target prediction tools; (iii) target validation tools; and (iv) manipulative miRNA expression tools. We also present an update about recently identified miRNA targets that play a key role in cardiovascular development and disorders.

MULTIDRUG RESISTANT TUBERCULOSIS - BIOMECHANISM, EPIDEMIOLOGY AND MANAGEMENT STRATEGIES.

Muitidrug resistant tuberculosis has shown an alarming increase and this assumes added importance in view of the increasing number of HIV infected patients. This article reviews the biomechanism of resistance and discusses the present stategies that are available and recommended to tackle the rising incidence of tuberculosis due to resistant mycobacteria.

A spectrophotometric method for determination of phosgene in air.

A reagent consisting of 0.4% of nitrobenzyl pyridine and 0.5% of sodium acetate in ethanol was found to be applicable as a sampling and coloring solution to a sensitive and relatively specific spectrophotometric determination of phosgene. This method is a modification of the method developed by Noweir et al. An aqueous 0.005% methyl orange pretrap was used to eliminate interference with chlorine and hydrogen chloride which are likely to be encountered in industrial environment. This colour produced by this method was stable for 2 hours, reduced by 3% and 7% after 3 and 4 hours of sampling respectively. The method is so sensitive as to detect phosgene at a concentration of 0.1 microgram/ml in the sampling solution with the coefficient of variation (CV) of 4.5%. The collection efficiency of phosgene with the sampling solution was found to be greater than 98% at a sampling rate of 1 l/min.

Evaluation and control of mercury vapor exposure in the cell house of chlor alkali plants.

A pilot study was carried out in the cell houses of three chlor alkali plants to assess level of exposure to mercury vapors among workers by air and biological monitoring. Overall airborne mercury concentrations (mg/m3) were found to range from 0.05 to 0.42 (mean, 0.21, n = 68), 0.03 to 0.16 (mean, .08, n = 49), and 0.02 to 0.17 (mean, 0.04, n = 26), whereas urinary mercury levels (mg/liter) of the exposed workers of the respective plants ranged from 0.076 to 0.592 (mean, 0.207, SD, 0.107, n = 19), 0.015 to 0.220 (mean, 0.070, SD, 0.054, n = 16), and 0.013 to 0.275 (mean, 0.06, SD, 0.054, n = 23). Unattended mercury spillage on the floor and improper sealing of the lids of the end boxes of electrolysis cells were found to be main factors attributing to prevalence of mercury vapors in excess of the permissible exposure limit of 0.05 mg/m3. Based on the deficiencies observed, appropriate control measures have been suggested to reduce airborne mercury vapor concentrations in the work environment.

Determination of 1, 2, 3, 4, 5, 6-hexachlorocyclohexane (BHC) in air by microdiffusion method.

A simple analytical method is described whereby 1,2,3,4,5, 6-hexachlorocyclohexane (BHC) is extracted from a sample in acetic acid, dechlorinated by reaction with zinc and acetic acid and the resultant benzene is volatilized and absorbed in a nitrating mixture by micro-diffusion technique. The m-dinitrobenzene formed in the nitrating mixture is spectrophotometrically analyzed by the butanone method. The sensitivity and precision (CV) of this method is found to be 5 micrograms +/- 5.0%.

A simple method of determination of nitrobenzene and nitrochlorobenzene in air and urine.

An analytical method based on the direct coupling of the dye sodium salt of 1,2-naphthoquinone-4-sulphonic acid with the chemically converted nitrobenzene (NB) and p-nitrochlorobenzene (NCB) to aniline and p-chloroaniline in aqueous medium (pH 7.0-9.0) is presented. The coupled dye is extracted in carbon tetrachloride and spectrophotometrically determined at 450 nm wavelength. Carbon tetrachloride is found to be a selective solvent for extraction of aniline and its analogous coupled derivative of the dye, thus the interference of the other urinary nitro and amine compounds normally present is removed. Ethanol and isopropyl alcohol are efficient sampling media for trapping airborne NB and NCB vapors. The sensitivity and precision of the method are 10 micrograms and 3.5%, respectively, for NB and NCB in air samples. The sensitivity and precision of this method for urinary NB and NCB estimation is 0.8 mg/L and 0.6 mg/L; and 6.1% and 4.0%, respectively.

Determination of urinary nitrobenzene by the microdiffusion method.

A simple, sensitive and specific analytical method based on microdiffusion of urinary nitrobenzene into a nitrating mixture and its subsequent determination by the butanone method is described in this paper. The method is sensitive to detect 0.2 mg/L of urinary nitrobenzene.