Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 139
Filter
1.
Mymensingh Med J ; 33(3): 888-896, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38944737

ABSTRACT

Chronic non-healing ulcers present significant challenges in diabetic, dermatological and surgical patients. Platelet-Rich Plasma (PRP), enriched with bioactive factors, offers promise for wound healing enhancement. The prospective observational study was done in the Department of Transfusion Medicine at AIIMS Bhopal for a period of two years, from April 2020 to 2022. This study evaluates PRP's efficacy, prepared via the single spin method, in non healing chronic ulcers. Aseptically, 100 ml of blood was drawn into CPDA (citrate-phosphate-dextrose-adenine) bags. PRP was prepared by centrifuging blood at 3400 rpm for 10 minutes, yielding PRP and buffy coat. Patient serum and 10.0% calcium gluconate were added to fibrin gel. PRP was injected around the ulcer and then dressed. Dressings were changed on the 5th, 15th and 20th days with PRP. The evaluation was done on day 30 using surface area and volume assessments. Thirteen patients aged 18-65 participated. The patients treated with single spin PRP (four females, nine males) had mean hemoglobin of 10.79±2.22gm/dL. Initial lesions (14.72cm²) significantly reduced to (8.78cm²) after application of single Spin PRP sessions (p=0.005). The PRP showed a mean platelet count of 1,527.00±192.26 × 109/L. Ulcer surface area decreased from 9.87cm² to 7.56cm²; lesion volume reduced from 14.72cm³ to 8.78cm³. Platelet count differences between whole blood and PRP were significant (p<0.05). The single-spin PRP method exhibited considerable improvements in healing parameters, showcasing its potential for chronic ulcer management.


Subject(s)
Platelet-Rich Plasma , Wound Healing , Humans , Female , Male , Middle Aged , Prospective Studies , Adult , Aged , Chronic Disease , Adolescent , Young Adult , Skin Ulcer/therapy
2.
J Dairy Sci ; 107(5): 2864-2882, 2024 May.
Article in English | MEDLINE | ID: mdl-38101729

ABSTRACT

Rumen-protected choline (RPC) promotes benefits in milk production, immunity, and health in dairy cows by optimizing lipid metabolism during transition period management and early lactation. However, the RPC success in dairy cows depends on choline bioavailability, which is affected by the type of protection used in rumen-protected choline. Therefore, our objectives were to determine the effects of a novel RPC on dry matter intake (DMI), identify markers of metabolism and immunity, and evaluate lactation performance. Dry Holstein (n = 48) cows at 245 ± 3 d of gestation were blocked by parity and assigned to control or RPC treatment within each block. Cows enrolled in the RPC treatment received 15 g/d of CholiGEM (Kemin Industries, Cavriago RE, Italy) from 21 d prepartum and 30 g/d of CholiGEM from calving to 21 d postpartum. During the transition period, DMI was measured daily, and blood was sampled weekly for energy-related metabolites such as ß-hydroxybutyrate (BHB), glucose, and nonesterified fatty acids (NEFA), as well as immune function markers such as haptoglobin (Hp) and lipopolysaccharide-binding protein (LPB). Vaginal discharge samples were collected at the calving and 7 d postpartum and stored in microcentrifuge tubes at -80°C until 16S rRNA sequencing. The main responses of body condition score, body weight, DMI, milk yield, milk components, and immune function markers were analyzed using the GLIMMIX procedure of SAS with the effects of treatment, time, parity, and relevant covariates added to the models. The relative abundance of microbiome α-diversity was evaluated by 3 indexes (Chao1, Shannon, and Simpson) and ß-diversity by principal coordinate analysis and permutational multivariate ANOVA. We found no differences in DMI in the pre- and postpartum periods. Cows fed RPC increased the yields of energy- and 3.5% fat-corrected milk and fat yield in primiparous and multiparous cows, with an interaction between treatment and parity for these lactation variables. However, we found no differences in milk protein and lactose up to 150 DIM between treatments. Glucose, NEFA, and BHB had no differences between the treatments. However, RPC decreased BHB numerically (control = 1.07 ± 0.13 vs. RPC = 0.63 ± 0.13) in multiparous on the third week postpartum and tended to reduce the incidence of subclinical ketosis (12.7% vs. 4.2%). No effects for Hp and LPB were found in cows fed RPC. Chao1, Shannon, and Simpson indexes were lower at calving in the RPC treatment than in the Control. However, no differences were found 7 d later for Chao1, Shannon, and Simpson indexes. The vaginal discharge microbiome was altered in cows fed RPC at 7 d postpartum. Fusobacterium, a common pathogen associated with metritis, was reduced in cows fed RPC. Rumen-protected choline enhanced lactation performance and health and altered the vaginal discharge microbiome which is a potential proxy for uterine healthy in dairy cows. The current study's findings corroborate that RPC is a tool to support adaptation to lactation and shed light on opportunities for further research in reproductive health.


Subject(s)
Cattle Diseases , Vaginal Discharge , Pregnancy , Female , Cattle , Animals , Choline/pharmacology , Choline/metabolism , Diet/veterinary , Dietary Supplements/analysis , Fatty Acids, Nonesterified , Rumen/metabolism , RNA, Ribosomal, 16S/metabolism , Postpartum Period/metabolism , Lactation/physiology , Glucose/metabolism , Vaginal Discharge/veterinary , Cattle Diseases/metabolism
3.
Arch Toxicol ; 93(6): 1473-1484, 2019 06.
Article in English | MEDLINE | ID: mdl-30923868

ABSTRACT

Humans are constantly exposed to a wide range of reactive and toxic chemicals from the different sources in everyday life. Identification of the exposed chemical helps in the detection and understanding the exposure associated adverse health effects. Covalent adducts of proteins and DNA formed after xenobiotics exposure may serve as readily measurable indicators of these exposures. Measuring the exposed chemicals with focus on adducts resulting from the nucleophilic interactions with blood proteins is useful in the development of diagnostic markers. Particularly, the most abundant proteins such as albumin and hemoglobin acts as dominant scavengers for many reactive chemicals in blood and can serve as excellent diagnostic candidates to determine the type of chemical exposure. This review focuses on the potential application of an adductomics approach for the screening of bimolecular adducts of chemical warfare agents (CWAs). Recent incidents of CWAs use in Syria, Malaysia, and the UK illustrate the continuing threat of chemical warfare agents in the modern world. Detection of CWAs and their metabolites in blood or in other body fluids of victims depends on immediate access to victims. Concentrations of intact CWAs in body fluids of surviving victims may decline rapidly within a few days. Certain CWAs, particularly nerve agents and vesicants, form covalent bonds with certain amino acids to form CWA-protein adducts. Proteins that are abundant in the blood, including albumin and hemoglobin, may carry these adducts longer after the original exposure. We searched MEDLINE and ISI Web of Science databases using the key terms "adductomics" "adducts of CWAs," "CWAs adducts detection in the biological samples," "protein adducts of CWAs," alone and in combination with the keywords "detection" "intoxication" "exposure" "adverse effects" and "toxicity." We also included non-peer-reviewed sources such as text books, relevant newspaper reports, and applicable Internet resources. We screened bibliographies of identified articles for additional relevant studies including non-indexed reports. These searches produced 1931 citations of which only relevant and nonduplicate citations were considered for this review. The analysis of biomedical samples has several purposes including detecting and identifying the type of chemical agent exposed, understanding the biological mechanism, assists in giving adequate treatment, determining the cause of death and providing evidence in a court of justice for forensic investigations. Rapid advances in the mass spectrometry to acquire high-quality data with greater resolution enabled the analysis of protein and DNA adducts of xenobiotics including CWAs and place the rapidly advancing 'adductomics' next to the other "-omics" technologies. Adductomics can serve as a powerful bioanalytical tool for the verification of CWAs exposure. This review mostly describes the protein adducts for nerve agents and vesicants, outlines the procedures for measuring adducts, and suggests the evolving (or future) use of adducts in the detection and verification of CWAs.


Subject(s)
Chemical Warfare Agents/toxicity , Chemical Warfare , DNA Adducts/chemistry , Humans , Mass Screening
4.
Hum Exp Toxicol ; 37(4): 373-389, 2018 Apr.
Article in English | MEDLINE | ID: mdl-28425350

ABSTRACT

Pyrazinamide (PYZ)-an essential component of primary drug regimen used for the treatment and management of multidrug resistant or latent tuberculosis-is well known for its hepatoxicity. However, the mechanism of PYZ-induced hepatotoxicity is still unknown to researchers. Studies have shown that the drug is metabolized in the liver to pyrazinoic acid (PA) and 5-hydroxy pyrazinoic acid (5-OHPA) which individually may cause different degrees of hepatotoxicity. To evaluate this hypothesis, PYZ, PA, and 5-OHPA were administered to albino Wistar rats orally (respectively, at 250, 125, and 125 mg kg-1 for 28 days). Compared to normal rats, PYZ and its metabolic products decreased the weights of dosed rats and induced liver injury and a status of oxidative stress as assessed by combined histopathological and biochemical analysis. Compared to normal controls, the biochemical and morphological changes were more aberrant in PA- and 5-OHPA-dosed rats with respect to those dosed with PYZ. Finally, the serum metabolic profiles of rats dosed with PYZ, PA, and 5-OHPA were measured and compared with those of normal control rats. With respect to normal control rats, the rats dosed with PYZ and 5-OHPA showed most aberrant metabolic perturbations in their sera as compared to those dosed with PA. Altogether, the study suggests that PYZ-induced hepatotoxicity might be associated with its metabolized products, where 5-OHPA contributes to a higher degree in its overall toxicity than PA.


Subject(s)
Antitubercular Agents/toxicity , Chemical and Drug Induced Liver Injury/etiology , Liver/drug effects , Metabolomics/methods , Pyrazinamide/analogs & derivatives , Pyrazinamide/toxicity , Toxicity Tests/methods , Administration, Oral , Animals , Antitubercular Agents/administration & dosage , Antitubercular Agents/blood , Biomarkers/blood , Biotransformation , Chemical and Drug Induced Liver Injury/blood , Chemical and Drug Induced Liver Injury/pathology , Liver/metabolism , Liver/ultrastructure , Male , Microscopy, Electron, Scanning , Multivariate Analysis , Oxidative Stress/drug effects , Proton Magnetic Resonance Spectroscopy , Pyrazinamide/administration & dosage , Pyrazinamide/blood , Rats, Wistar , Risk Assessment , Time Factors
5.
Neurotox Res ; 33(4): 738-748, 2018 05.
Article in English | MEDLINE | ID: mdl-28929435

ABSTRACT

Neuroprotection from nerve agent such as soman-induced neural damage is a major challenge for existing drugs. Nerve agent exposure can cause many neural effects in survivors arising mainly due to acetylcholinesterase (AChE) inhibition or death within minutes. Unraveling the mechanisms underlying the nerve agent-induced multiple neurological effects is useful to develop better and safe drugs. The present study aimed to understand the molecular response during soman exposure and to evaluate the neuroprotective efficacy of galantamine on nerve agent-induced neurotoxic changes. mRNA expression studies using quantitative real-time PCR revealed significant changes in S-100ß, Gfap, c-fos, and Bdnf in the hippocampus and piriform cortex after soman (90 µg/kg, s.c) exposure. Immunoblot analysis showed acute soman exposure significantly increased the protein levels of neuroglial markers (S100-ß and GFAP); c-Fos and protein oxidation in discrete rat brain areas indicate their role in nerve agent-induced neurotoxicity. Induction of BDNF levels during soman exposure may indicate the recovery mechanisms activation. AChE was inhibited in the blood and brain up to 82% after soman exposure. Antidotal treatment with galantamine alone (3 mg/kg) and galantamine plus atropine (10 mg/kg) has protected animals from nerve agent-induced intoxication, death, and soman-inhibited AChE up to 45% in the blood and brain. Animal received galantamine displayed increased levels of neuroprotective genes (nAChRα-7, Bcl-2, and Bdnf) in the brain suggest the neuroprotective value of galantamine. Neuroglial changes, c-Fos, and protein oxidation levels significantly reduced after galantamine and galantamine plus atropine treatment indicate their potential antidotal value in nerve agent treatment.


Subject(s)
Brain , Galantamine/pharmacology , Nerve Agents/pharmacology , Neuroglia/drug effects , Neuroprotective Agents/pharmacology , Soman/pharmacology , Acetylcholinesterase/metabolism , Animals , Atropine/pharmacology , Brain/cytology , Brain/drug effects , Brain/metabolism , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/metabolism , Gene Expression Regulation/drug effects , Glial Fibrillary Acidic Protein/genetics , Glial Fibrillary Acidic Protein/metabolism , Male , Muscarinic Antagonists/pharmacology , Protein Carbonylation/drug effects , Proto-Oncogene Proteins c-fos/genetics , Proto-Oncogene Proteins c-fos/metabolism , RNA, Messenger/metabolism , Rats , Rats, Wistar , S100 Calcium Binding Protein beta Subunit/genetics , S100 Calcium Binding Protein beta Subunit/metabolism , Time Factors
6.
J Postgrad Med ; 64(1): 53-55, 2018.
Article in English | MEDLINE | ID: mdl-28862245

ABSTRACT

We report a case of a 36-year-old man with a medical history of human immunodeficiency virus (HIV) infection who presented with hypomimia, hypophonia, bradykinesia, rigidity, and freezing of gait. His clinical presentation and magnetic resonance imaging were consistent with HIV encephalopathy with involvement of the bilateral basal ganglia and diffuse leukoencephalopathy. We initiated a trial of carbidopa-levodopa. The dose was escalated to 1050 mg levodopa daily. Amantadine was also started. The patient was closely monitored for behavioral, neurological, or systemic side effects. He tolerated therapy well without adverse effects. The patient's neurological status significantly improved with levodopa, including hypomimia, hypophonia, bradykinesia, and fluidity of gait. This case demonstrates that carbidopa-levodopa can be safely utilized to manage parkinsonism in an adult patient with HIV encephalopathy.


Subject(s)
AIDS Dementia Complex/drug therapy , Amantadine/therapeutic use , Antiparkinson Agents/therapeutic use , Carbidopa/administration & dosage , Gait Disorders, Neurologic/etiology , Hypokinesia/etiology , Levodopa/administration & dosage , Adult , Carbidopa/therapeutic use , Drug Combinations , Humans , Leukoencephalopathies , Levodopa/therapeutic use , Male , Treatment Outcome
7.
Indian J Med Res ; 146(Supplement): S1-S7, 2017 Nov.
Article in English | MEDLINE | ID: mdl-29578188

ABSTRACT

BACKGROUND & OBJECTIVES: Hyperosmolar hyperglycaemic state (HHS) is a medical emergency, but there is a paucity of studies reporting the spectrum of neurological manifestations of HHS. We, therefore, report the neurological spectrum, triggering factors and outcome of HHS in general neurology practice. METHODS: The records of the patients with HHS were extracted from computerized hospital information system and those managed currently were prospectively included. The demographic, clinical manifestations, duration of diabetes and precipitating events such as infection, stress and stroke were noted. Patients with HHS were categorized into seizure, movement disorder and encephalopathy groups. Their electroencephalography, magnetic resonance imaging (MRI) findings and outcome were noted. RESULTS: There were 17 patients with HHS (age range 40 and 75 yr) and seven were females. Seven patients were diabetic for five years, one for four years, one for one year and four were diagnosed after the occurrence of HHS. Four patients had epilepsia partialis continua persisting for 72-360 h, one patient had focal seizures and his MRI revealed T2 hyperintensity in frontal region in one patient and cerebellar vermian hyperintensity in another. All the five patients improved, but two had neurological deficits on discharge. Nine patients had encephalopathy which was precipitated by stroke in six patients, urinary infections in two and meningitis in one. Three females had hemichorea-hemiballismus syndrome, which was triggered by infections. Abnormal movements lasted 5-10 days and responded to correction of hyperosmolarity. Nine out of 17 patients improved completely whereas the remaining eight had partial recovery, these patients had stroke, ventilator-related complications or meningoencephalitis. INTERPRETATION & CONCLUSIONS: The most common presentation of HHS was encephalopathy (9) followed by seizure (5) and hemichorea-hemiballismus syndrome (3) which responded to the correction of hyperosmolar state.


Subject(s)
Hyperglycemic Hyperosmolar Nonketotic Coma/complications , Adult , Aged , Chorea/etiology , Coma/etiology , Dyskinesias/etiology , Female , Humans , Male , Middle Aged , Neurology , Seizures/etiology
10.
Neuroscience ; 320: 57-68, 2016 Apr 21.
Article in English | MEDLINE | ID: mdl-26844388

ABSTRACT

cAMP response-element binding protein (CREB)-dependent genes are differentially expressed in brains of temporal lobe epilepsy (TLE) patients and also in animal models of TLE. Previous studies have demonstrated the importance of CREB regulated transcription in TLE. However, the role of the key regulator of CREB activity, CREB-regulated transcription coactivator 1 (CRTC1), has not been explored in epilepsy. In the present study the pilocarpine-induced status epilepticus (SE) model of TLE was used to study the regulation of CRTC1 during and following SE. Nuclear translocation of CRTC1 is critical for its transcriptional activity, and dephosphorylation at serine 151 residue via calcineurin phosphatase regulates cytoplasmic to nuclear transit of CRTC1. Here, we examined the localization and phosphorylation (Ser151) of CRTC1 in SE-induced rat hippocampus at two different time points after SE onset. One hour after SE onset, we found that CRTC1 translocates to the nucleus of CA1 neurons but not CA3 or dentate granule neurons. We further found that this CRTC1 nuclear localization is independent of Ser151 dephosphorylation since we did not detect any difference in dephosphorylation of Ser151 between control and SE animals at this time point. In contrast, 48 h after SE CRTC1 shows increased nuclear localization in the dentate gyrus (DG) of the SE-induced rats. At 48 h after SE, FK506 treatment blocked CRTC1 nuclear localization and dephosphorylation of Ser151. Our results provide evidence that CREB cofactor CRTC1 translocates into the nucleus of a distinct subset of hippocampal neurons during and following SE and this translocalization is regulated by calcineurin at a later time point following SE. Nuclear CRTC1 can bind to CREB possibly altering transcription during epileptogenesis.


Subject(s)
Cyclic AMP Response Element-Binding Protein/metabolism , Epilepsy, Temporal Lobe/metabolism , Hippocampus/metabolism , Status Epilepticus/metabolism , Transcription Factors/metabolism , Active Transport, Cell Nucleus , Animals , Convulsants/toxicity , Disease Models, Animal , Fluorescent Antibody Technique , Immunoblotting , Male , Pilocarpine/toxicity , Rats , Rats, Sprague-Dawley , Real-Time Polymerase Chain Reaction
11.
Sci Total Environ ; 542(Pt A): 551-61, 2016 Jan 15.
Article in English | MEDLINE | ID: mdl-26540602

ABSTRACT

Quantification of greenhouse gases (GHGs) emissions from agriculture is necessary to prepare the national inventories and to develop the mitigation strategies. Field experiments were conducted during 2008-2010 at the experimental farm of the Indian Agricultural Research Institute, New Delhi, India to quantify nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions from soils under cereals, pulses, millets, and oilseed crops. Total cumulative N2O emissions were significantly different (P>0.05) among the crop types. Emission of N2O as percentage of applied N was the highest in pulses (0.67%) followed by oilseeds (0.55%), millets (0.43%) and cereals (0.40%). The emission increased with increasing rate of N application (r(2)=0.74, P<0.05). The cumulative flux of CH4 from the rice crop was 28.64±4.40 kg ha(-1), while the mean seasonal integrated flux of CO2 from soils ranged from 3058±236 to 3616±157 kg CO2 ha(-1) under different crops. The global warming potential (GWP) of crops varied between 3053 kg CO2 eq. ha(-1) (pigeon pea) and 3968 kg CO2 eq. ha(-1) (wheat). The carbon equivalent emission (CEE) was least in pigeon pea (833 kg C ha(-1)) and largest in wheat (1042 kg C ha(-1)). The GWP per unit of economic yield was the highest in pulses and the lowest in cereal crops. The uncertainties in emission values varied from 4.6 to 22.0%. These emission values will be useful in updating the GHGs emission inventory of Indian agriculture.

12.
Indian J Physiol Pharmacol ; 59(2): 136-47, 2015.
Article in English | MEDLINE | ID: mdl-26685500

ABSTRACT

Cold pressor test (CPT) is a well-known method for evaluating non-baroreflex mediated autonomic cardiovascular functions in humans. It has been reported that autonomic cardiovascular response to CPT differs in males and females and that heat stress attenuates the increase in arterial blood pressure during CPT. Study has also indicated that heat stress attenuates the increase in arterial blood pressure during CPT. The present study assessed the autonomic cardiovascular reactivity in males and females during cold pressor test before and after whole body heating for 40 min. 20 healthy Indian males and 18 females participated in the study. The participants were exposed to 40°C dry bulb temperature and 40% relative humidity in a simulated thermal chamber. They performed CPT before and after heat stress and their beat to beat heart rate and blood pressure were recorded. It was observed that baroreflex sensitivity (BRS) was significantly lower in females during CPT before heat stress (p < 0.01) as well as after heat stress (p < 0.01). Moreover, following whole body heating, the BRS during CPT increased slightly in females but not in males. Stroke Volume (SV) increased significantly during CPT before heat stress in females from pre-heat baseline (82 ml/beat vs. 101 ml/beat) (p < 0.001) as well as during CPT after heat stress from post-heat baseline (75 ml/beat vs. 95 ml/ beat) (p < 0.01). SV increased significantly in males during CPT after heat stress only (p < 0.01) as compared to post-heat baseline (82.5 ml/beat vs. 94.5 ml/beat). Frequency domain analysis of heart rate variability indicated that during CPT, low frequency power in males was higher than females (p < 0.05) and high frequency power was higher in females than males (p < 0.05). This suggests that autonomic modulation of cardiovascular function during CPT in males is mediated mainly via sympathetic neural system and in females it is mediated via vagal system. LF/HF ratio during CPT was found to be significantly higher in males (2.54) than females (1.27) before heat stress (p < 0.01).


Subject(s)
Blood Pressure/physiology , Heart Rate/physiology , Hot Temperature , Adult , Autonomic Nervous System/physiology , Female , Humans , Male , Muscles/innervation , Sex Characteristics
13.
J Chromatogr A ; 1426: 16-23, 2015 Dec 24.
Article in English | MEDLINE | ID: mdl-26639217

ABSTRACT

In this work, a glass capillary based microfluidic electromembrane extraction (µ-EME) was demonstrated for the first time. The device was made by connecting an auxillary borosilicate glass tubing (O.D. 3mm, I.D. 2mm) perpendicular to main borosilicate glass capillary just below one end of the capillary (O.D. 8mm, I.D. 1.2mm). It generated the distorted T-shaped device with inlet '1' and inlet '2' for the introduction of sample and acceptor solutions, respectively. At one end of this device (inlet '2'), a microsyringe containing acceptor solution along with hollow fiber (O.D. 1000µm) was introduced. This configuration creates the micro-channel between inner wall of glass capillary and outer surface of hollow fiber. Sample solution was pumped into the system through another end of glass capillary (inlet '1'), with a micro-syringe pump. The sample was in direct contact with the supported liquid membrane (SLM), consisted of 20% (w/w) di-(2-ethylhexyl)phosphate in 2-nitrophenyl octyl ether immobilized in the pores of the hollow fiber. In the lumen of the hollow fiber, the acceptor phase was present. The driving force for extraction was direct current (DC) electrical potential sustained over the SLM. Highly polar (logP=-2.5 to 1.4) basic degradation products of nitrogen mustard and VX were selected as model analytes. The influence of chemical composition of SLM, extraction time, voltage and pH of donor and acceptor phase were investigated. The model analytes were extracted from 10µL of pure water with recoveries ranging from 15.7 to 99.7% just after 3min of operation time. Under optimized conditions, good limits of detection (2-50ngmL(-1)), linearity (from 5-1000 to 100-1000ngmL(-1)), and repeatability (RSDs below 11.9%, n=3) were achieved. Applicability of the proposed µ-EME was proved by recovering triethanolamine (31.3%) from 10µL of five times diluted original water sample provided by the Organization for the Prohibition of Chemical Weapons during 28th official proficiency test.


Subject(s)
Mechlorethamine/isolation & purification , Microfluidics/instrumentation , Microfluidics/methods , Organothiophosphorus Compounds/isolation & purification , Water/chemistry , Electricity , Ethers/chemistry , Glass , Mechlorethamine/chemistry , Membranes, Artificial , Organophosphates/chemistry , Organothiophosphorus Compounds/chemistry
14.
J Chromatogr A ; 1423: 54-62, 2015 Dec 04.
Article in English | MEDLINE | ID: mdl-26554296

ABSTRACT

Present study aimed at graphene surface modification to achieve selective analyte binding in dispersive solid phase extraction. Magnetic graphene - polystyrene sulfonic acid (MG-PSS) cation exchange nano-composite was prepared by non-covalent wrapping method. Composite was characterized by FT-IR and zeta potential. Material exhibited good dispersion in water and high exchange capacity of 1.97±0.16mMg(-1). Prepared nano-sorbent was then exploited for the cation exchange extraction and gas chromatography mass spectrometric analysis of Chemical Weapons Convention relevant aminoalcohols and ethanolamines from aqueous samples. Extraction parameters such as sorbent amount, extraction time, desorption conditions and sample pH were optimized and effect of common matrix interferences such as polyethylene glycol and metal salts was also studied. Three milligram of sorbent per mL of sample with 20min of extraction time at room temperature afforded 70-81% recoveries of the selected analytes spiked at concentration level of 1µgmL(-1). Method showed good linearity in the studied range with r(2)≥0.993. The limits of detection and limits of quantification ranged from 23 to 54ngmL(-1) and 72 to 147ngmL(-1), respectively. The relative standard deviation for intra- and inter-day precision ranged from 4.6 to 10.2% and 7.4 to 14.8% respectively. Applicability of the method to different environmental samples as well as the proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons (OPCW) was also ascertained.


Subject(s)
Amino Alcohols/isolation & purification , Environmental Monitoring/methods , Ethanolamines/isolation & purification , Graphite/chemistry , Nanocomposites/chemistry , Polystyrenes/chemistry , Water/chemistry , Amino Alcohols/analysis , Ethanolamines/analysis , Gas Chromatography-Mass Spectrometry , Solid Phase Extraction , Spectroscopy, Fourier Transform Infrared , Water Pollutants, Chemical/analysis
15.
J Chromatogr A ; 1394: 9-17, 2015 May 15.
Article in English | MEDLINE | ID: mdl-25828545

ABSTRACT

Present study deals with the preparation and evaluation of graphene based magnetic nano-composite for dispersive solid phase extraction of Chemical Weapons Convention (CWC) relevant chemicals from aqueous samples. Nano-composite, Fe3O4@SiO2-G was synthesized by covalently bonding silica coated Fe3O4 onto the graphene sheets. Nerve agents (NA), Sulfur mustard (SM) and their non-toxic environmental markers were the target analytes. Extraction parameters like amount of sorbent, extraction time and desorption conditions were optimized. Dispersion of 20 milligram of sorbent in 200mL of water sample for 20min. followed by methanol/chloroform extraction produced average to good recoveries (27-94%) of targeted analytes. Recoveries of real agents exhibited great dependency upon sample pH and ionic strength. Sarin produced maximum recovery under mild acidic conditions (56% at pH 5) while VX demanded alkaline media (83% at pH 9). Salts presence in the aqueous samples was found to be advantageous, raising the recoveries to as high as 94% for SM. Excellent limits of detection (LOD) for sulphur mustard and VX (0.11ngmL(-1) and 0.19ngmL(-1) respectively) proved the utility of the developed method for the off-site analysis of CWC relevant chemicals.


Subject(s)
Chemical Warfare Agents/isolation & purification , Ferric Compounds , Graphite , Nanocomposites , Silicon Dioxide , Solid Phase Extraction/methods , Water Pollutants, Chemical/isolation & purification , Hydrogen-Ion Concentration , Limit of Detection , Mustard Gas/isolation & purification , Organophosphorus Compounds/isolation & purification , Osmolar Concentration , Water/chemistry
16.
J Chromatogr A ; 1370: 80-92, 2014 Nov 28.
Article in English | MEDLINE | ID: mdl-25454132

ABSTRACT

Environmental markers of chemical warfare agents (CWAs) comprise millions of chemical structures. The simultaneous detection and identification of these environmental markers poses difficulty due to their diverse chemical properties. In this work, by using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF), a generic analytical method for the detection and identification of wide range of environmental markers of CWAs (including precursors, degradation and co-products of nerve agents and sesqui-mustards) in drinking water, was developed. The chromatographic analysis of 55 environmental markers of CWAs including isomeric and isobaric compounds was accomplished within 20 min, using 1.8 µm particle size column. Subsequent identification of the compounds was achieved by the accurate mass measurement of either protonated molecule [M+H](+) or ammonium adduct [M+NH4](+) and fragment ions. Isomeric and isobaric compounds were distinguished by chromatographic retention time, characteristic fragment ions generated by both in-source collision induced dissociation (CID) and CID in the collision cell by MS/MS experiments. The exact mass measurement errors for all ions were observed less than 3 ppm with internal calibration. The method limits of detection (LODs) and limits of quantification (LOQs) were determined in drinking water and found to be 1-50 ng mL(-1) and 5-125 ng mL(-1), respectively. Applicability of the proposed method was proved by determining the environmental markers of CWAs in aqueous samples provided by Organization for the Prohibition of Chemical Weapons during 34th official proficiency test.


Subject(s)
Chemical Warfare Agents/analysis , Chromatography, High Pressure Liquid/methods , Drinking Water/chemistry , Prodrugs/analysis , Tandem Mass Spectrometry/methods , Water Pollutants, Chemical/analysis , Chemical Warfare Agents/chemistry , Limit of Detection , Prodrugs/chemistry , Water Pollutants, Chemical/chemistry
17.
J Chromatogr A ; 1359: 325-9, 2014 Sep 12.
Article in English | MEDLINE | ID: mdl-25103280

ABSTRACT

This study deals with the solid supported in situ derivatization extraction of acidic degradation products of nerve agents present in aqueous samples. Target analytes were alkyl alkylphosphonic acids and alkylphosphonic acids, which are important environmental signatures of nerve agents. The method involved tert-butyldimethylchlorosilane mediated in situ silylation of analytes on commercially available diatomaceous solid phase extraction cartridges. Various parameters such as derivatizing reagent, its concentration, reaction time, temperature and eluting solvent were optimized. Recoveries of the analytes were determined by GC-MS which ranged from 60% to 86%. The limits of detection (LOD) and limit of quantification (LOQ) with selected analytes were achieved down to 78 and 213ngmL(-1) respectively, in selected ion monitoring mode. The successful applicability of method was also demonstrated on samples of biological origin such as plasma and to the samples received in 34th official proficiency test conducted by the Organization for Prohibition the of Chemical Weapons.


Subject(s)
Chemical Warfare Agents/analysis , Chemical Warfare Agents/isolation & purification , Gas Chromatography-Mass Spectrometry/methods , Solid Phase Extraction/methods , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/isolation & purification , Animals , Limit of Detection , Mice , Plasma/chemistry
18.
Indian J Physiol Pharmacol ; 58(3): 275-9, 2014.
Article in English | MEDLINE | ID: mdl-25906611

ABSTRACT

Armed forces personnel including military aviators are quite often exposed concurrently to various environmental stressors like high environmental temperature and hypoxia. Literatures have suggested that exposure to one environmental stressor may modify the physiological response on subsequent exposure to same or different stressor. The present study was undertaken to investigate the impact of cross tolerance between two environmental stressors of aviation (heat and hypoxia) in ten healthy adult males in a simulated altitude chamber in a within subject experimental study. They were assessed for their convergence ability of the eyes at ground and at simulated altitude of 18,000 ft with or without pre-exposure to heat stress. Subjective convergence at simulated altitude of 18,000 ft did not show any improvement following pre-exposure to heat stress. Objective convergence was improved following pre-exposure to heat stress and was found to be 10.76 cm and 9.10 cm without and with heat stress respectively at simulated altitude of 18,000 ft. Improved objective convergence at high altitude as a result of pre-exposure to heat stress is indicative of better ocular functions. This might benefit aviators while flying at hypoxic condition.


Subject(s)
Altitude , Convergence, Ocular/physiology , Hot Temperature , Adult , Heat-Shock Proteins/physiology , Humans , Male
19.
J Chromatogr A ; 1311: 170-5, 2013 Oct 11.
Article in English | MEDLINE | ID: mdl-24016719

ABSTRACT

Present study deals with the on-matrix derivatization-extraction of aminoalcohols and thiodiglycols, which are important precursors and/or degradation products of VX analogues and vesicants class of chemical warfare agents (CWAs). The method involved hexamethyldisilazane (HMDS) mediated in situ silylation of analytes on the soil. Subsequent extraction and gas chromatography-mass spectrometry analysis of derivatized analytes offered better recoveries in comparison to the procedure recommended by the Organization for the Prohibition of Chemical Weapons (OPCW). Various experimental conditions such as extraction solvent, reagent and catalyst amount, reaction time and temperature were optimized. Best recoveries of analytes ranging from 45% to 103% were obtained with DCM solvent containing 5%, v/v HMDS and 0.01%, w/v iodine as catalyst. The limits of detection (LOD) and limit of quantification (LOQ) with selected analytes ranged from 8 to 277 and 21 to 665ngmL(-1), respectively, in selected ion monitoring mode.


Subject(s)
Amino Alcohols/isolation & purification , Chemical Warfare Agents/isolation & purification , Gas Chromatography-Mass Spectrometry/methods , Soil/chemistry , Sulfhydryl Compounds/isolation & purification , Limit of Detection , Organosilicon Compounds/chemistry
20.
Analyst ; 137(23): 5648-53, 2012 Dec 07.
Article in English | MEDLINE | ID: mdl-23086107

ABSTRACT

Conventional methods of detection of chemical warfare agents (CWAs) based on chromogenic reactions are time and solvent intensive. The development of cost, time and solvent effective microfluidic paper based analytical devices (µ-PADs) for the detection of nerve and vesicant agents is described. The detection of analytes was based upon their reactions with rhodamine hydroxamate and para-nitrobenzyl pyridine, producing red and blue colours respectively. Reactions were optimized on the µ-PADs to produce the limits of detection (LODs) as low as 100 µM for sulfur mustard in aqueous samples. Results were quantified with the help of a simple desktop scanner and Photoshop software. Sarin achieved a linear response in the two concentration ranges of 20-100 mM and 100-500 mM, whereas the response of sulfur mustard was found to be linear in the concentration range of 10-75 mM. Results were precise enough to establish the µ-PADs as a valuable tool for security personnel fighting against chemical terrorism.


Subject(s)
Chemical Warfare Agents/analysis , Microfluidic Analytical Techniques/instrumentation , Rhodamines/chemistry , Chromogenic Compounds , Limit of Detection , Mustard Gas/analysis , Paper , Pyridines/chemistry , Sarin/analysis
SELECTION OF CITATIONS
SEARCH DETAIL
...