Comparative safety evaluation of riot control agents of synthetic and natural origin.

Riot control agents (RCA) are lachrymatory, irritating compounds which temporarily incapacitate the uncontainable crowd. Ortho-Chlorobenzylidene-malononitrile (CS), 2-chloroacetophenone (CN), dibenz[b,f]1:4-oxazepine (CR), and nonivamide (PAVA) are synthetic RCAs, while oleoresin extract of chili known as oleoresin capsicum (OC) a natural irritant has been in use by various law enforcement agencies. Though efficacy of these agents is beyond doubt, they suffer from certain drawbacks including toxicity, production cost, and ecological compatibility. Presently, we have evaluated the safety of CR, OC, and PAVA on inhalation variables along with oral lethality. Additionally, the liver function test (LFT) in serum and lungs function was evaluated in broncho-alveolar-lavage fluid (BALF), both collected on the 14th day after RCA exposure. Animals then sacrificed and histopathology of liver and lungs was carried out. Results showed OC and PAVA to be more toxic than CR with an oral LD50 of 150 and 200 mg/kg body weight, respectively, while CR was safe at >3 g/kg body weight. All three agents caused severe impairment of respiratory variables bringing down normal respiration by >80% with rise in sensory irritation. Recovery from the irritating effect of CR was more rapid than OC and PAVA. LFT and BALF variables were not significantly different from that of control. There were no remarkable histopathological changes in liver and lungs. Hence, as per results, CR is safest among all synthetic and natural origin RCAs and can be safely used for effective dispersion of disobedient mob.

Time- and temperature-dependent changes in cytochrome c oxidase activity and cyanide concentration in excised mice organs and mice cadavers.

Postmortem stability of cyanide biomarkers is often disputed. We assessed the time and temperature-dependent changes in cytochrome c oxidase (CCO) activity and cyanide concentration in various organs of mice succumbing to cyanide. Immediately after death, excised mice organs and mice cadavers were stored at room temperature (35°C ± 5°C) or in frozen storage (-20°C ± 2°C). At various times after death, CCO activity and cyanide concentrations were measured in excised mice organs or organs removed from mice cadavers. The study revealed that (i) measuring both the biomarkers in mice cadavers was more reliable compared to excised mice organs, (ii) measuring temporal CCO activity and cyanide concentration in vital organs from mice cadavers (room temperature) was reliable up to 24 h, and (iii) CCO activity in the brain and lungs and cyanide concentration in organs from mice cadavers (frozen) were measurable beyond 21 days. This study will be helpful in postmortem determination of cyanide poisoning.

Ameliorating effect of S-2(ω-aminoalkylamino) alkylaryl sulfide (DRDE-07) on sulfur mustard analogue, 2-chloroethyl ethyl sulfide-induced oxidative stress and inflammation.

Sulfur mustard (SM; 2,2'-dichloro diethyl sulfide), an alkylating chemical warfare agent, poses a major threat in both military conflict and chemical terrorism situations. 2-chloroethyl ethyl sulfide (CEES) is a monofunctional analogue of SM, frequently used in laboratory settings, therefore increasing chances of its exposure. S-2(ω-aminoalkylamino) alkylaryl sulfide (DRDE-07) is an analogue of amifostine reported to have protective effects against SM but its effect on CEES is largely unexplored. Therefore, this study was planned to explore the effects of DRDE-07 against CEES-induced toxicity. 0.75 LD50 (1068 mg/kg) of CEES was exposed percutaneously in the presence or absence of DRDE-07 (249 mg/kg p.o.) which is given prophylactically (before 30 minute) to male mice. Animals were sacrificed on 24 h, 7th day and 14th day of CEES exposure, and tissues were collected to study oxidative stress and inflammatory markers. CEES exposure depleted intracellular GSH level and activities of GSH-linked enzymes (GR, GPx and GST) which play a major role in GSH metabolism. CEES exposure augmented lipid peroxidation indicating severe oxidative stress. It also initiated inflammation causing an increase in proinflammatory (IL1-α, IL1-ß, IL-6, TNF-α and IFN-ϒ) and corresponding decrease in anti-inflammatory cytokines (IL-4 and IL-10). This was also accompanied by neutrophils infiltration indicated by higher than normal myeloperoxidase (MPO) levels. DRDE-07 efficiently reduced the oxidative stress and also facilitated to resolve inflammatory alterations. This study thus evaluated the beneficial role of DRDE-07 in ameliorating the deleterious effects of CEES and can be potentially used against SM/CEES poisoning.

Cyanide-induced changes in the levels of neurotransmitters in discrete brain regions of rats and their response to oral treatment with alpha-ketoglutarate.

Cyanide is a potential suicidal, homicidal and chemical warfare agent. It produces histotoxic hypoxia following inhibition of cytochrome c oxidase, a terminal respiratory chain enzyme. The profound metabolic changes lead to neurotoxicity including alterations in the levels of neurotransmitters. The present study addressed the effect of acute exposure of lethal and sub-lethal doses of potassium cyanide (KCN; 0.75 or 2.0 LD50; po) on the levels of neurotransmitters in discrete brain regions of rats and its response to treatment with alpha-ketoglutarate (alpha-KG; 0.5 g/kg; po; -10 min) alone or with sodium thiosulphate (STS; 1.0 g/kg; ip; -15 min). KCN significantly decreased norepinephrine, dopamine and 5-hydroxytryptamine levels in different brain regions which were resolved by alpha-KG and/or STS. Corpus striatum and hippocampus were more sensitive as compared to cerebral cortex and hypothalamus. alpha-KG, a potential cyanide antidote alone or with STS showed neuroprotective effects against cyanide.

Protection of PC12 cells from chemical ischemia induced oxidative stress by Fagonia arabica.

Fagonia arabica (Zygophyllaceae) is an important Ayurvedic herb, grows throughout arid regions of India, has been widely used as a folk remedy by the indigenous people for its anti-inflammatory, analgesic and antipyretic effects. In the present study, antioxidant potential of F. arabica and the associated mechanism of antioxidant defence in rat pheochromocytoma (PC12) cells subjected to chemical ischemia was studied. Effect of total extract of F. arabica was studied for its antioxidant potential on the chemical ischemia induced PC12 cells. Alterations in the activities of cellular antioxidant enzymes (SOD, CAT, GSH-Px and GSH-R) were measured. Antioxidant potential of herb (ABTS), extent of lipid peroxidation (MDA and 4-HAE), total antioxidant status (TAS) and total glutathione (reduced, oxidized and their ratio) were evaluated. F. arabica scavenges the free radicals (ABTS(.)+), and showed a concentration dependent antioxidant activity, highest being at 1000 microg/ml. Its treatment with ischemic cells ameliorates the GSH and TAS levels and also helps the cells to restore the activities of the cellular antioxidative enzymes and also reduced the degree of lipid peroxidation. F. arabica scavenges the free radicals and attenuates oxidative stress mediated cell injury during ischemia.

Activity and gene expression profile of certain antioxidant enzymes in different organs of rats after subacute cyanide exposure: effect of alpha-ketoglutarate.

Oxidative stress plays a crucial role in mediating cyanide toxicity. The present study addresses the effect of cyanide on activity and gene-expression profile of certain antioxidant enzymes and the expression of heat shock protein (HSP-70) in different organs of rats. Rats were treated with 0.50 LD(50) (7.0 mg/kg) of potassium cyanide (KCN; oral) and/or alpha-ketoglutarate (A-KG; 1.0 g/kg; oral) daily for 14 days, and various biochemical variables were measured in brain, liver, and kidney after 7 and 14 days of treatments and a 7-day recovery period. Cyanide significantly reduced the activity of glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CA) in all the organs after 7 days, while the activity of GPx in brain, liver, and kidney, GR in liver, and CA in brain remained diminished up to 14 days. The gene-expression profile of corresponding enzymes did not show any difference between the control and treatment groups. Elevated levels of malondialdehyde were observed in brain and kidney 7 and 14 days after cyanide. Cyanide also increased the expression of HSP-70 activity in brain after 7 days alone. Regression of toxicity was observed after the withdrawal of KCN. Treatment of A-KG was found to prevent all the biochemical alterations caused by cyanide. This study reveals that oxidative stress caused by cyanide was independent of the expression of antioxidant enzyme activity at the gene level, and all changes responded favorably to A-KG, indicating its therapeutic potential.

Secretory factors of human neuroblastoma (IMR-32) and human glioblastoma (U87MG) cell lines induce neurite outgrowths in PC12 cells.

Neurite outgrowth is essential for the communication of the nervous system. The rat Pheochromocytoma (PC12) cells are commonly used in the neuronal cell study. It is well known that exogenous stimuli such as Nerve Growth Factor (NGF) induce neurite outgrowth. In the present study it has been investigated whether or not the conditioned medium from human neuroblastoma cell line (IMR-32) and human glioblastoma cell line (U87MG) may augment neurite outgrowth in PC12 cells. PC12 were cultured with and without conditioned media of IMR-32 and U87MG. The result showed that both the conditioned media induce neurite outgrowth within 48 hr and stops further proliferation of PC12 cells. However no outgrowth was noted in PC12 cells incubated without conditioned medium. In conclusion, it is shown that both the conditioned media (IMR-32 and U87MG) have the potential to induce the neurite outgrowth in the PC12 cells.

Differential diagnosis of tuberculous meningitis from partially-treated pyogenic meningitis by cell ELISA.

BACKGROUND: Tuberculous meningitis (TBM) is a major global health problem, and it is sometimes difficult to perform a differential diagnosis of this disease from other diseases, particularly partially-treated pyogenic meningitis (PTPM). In an earlier study, we demonstrated the presence of a 30-kD protein antigen in cerebrospinal fluid (CSF) of TBM patients. We have also shown that lymphocytes from CSF of TBM patients respond differently to this antigen than do those from PTPM patients. The purpose of this study was to develop an assay that can discriminate between TBM and PTPM. METHODS: We developed a cell enzyme-linked immunosorbant assay (Cell ELISA) to quantitatively measure production of antibodies against the 30-kD protein in B cells from CSF of TBM and PTPM patients. RESULTS: The cell ELISA yielded 92% (11/12) sensitivity and 92% (11/12) specificity for the differential diagnosis of TBM from PTPM. CONCLUSION: When induced with the 30-kD protein antigen, B cells derived from CSF of TBM patients respond to IgG production within 24 h while those derived from PTPM patients do not respond.