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1.
Annu Rev Public Health ; 44: 1-20, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36542771

RESUMO

Several peer-reviewed papers and reviews have examined the relationship between exposure to air pollution and COVID-19 spread and severity. However, many of the existing reviews on this topic do not extensively present the statistical challenges associated with this field, do not provide comprehensive guidelines for future researchers, and review only the results of a relatively small number of papers. We reviewed 139 papers, 127 of which reported a statistically significant positive association between air pollution and adverse COVID-19 health outcomes. Here, we summarize the evidence, describe the statistical challenges, and make recommendations for future research. To summarize the 139 papers with data from geographical locations around the world, we also present anopen-source data visualization tool that summarizes these studies and allows the research community to contribute evidence as new research papers are published.


Assuntos
Poluição do Ar , COVID-19 , Humanos , COVID-19/epidemiologia , Visualização de Dados , Material Particulado/efeitos adversos , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Poluição do Ar/efeitos adversos , Avaliação de Resultados em Cuidados de Saúde
2.
Philos Trans A Math Phys Eng Sci ; 379(2197): 20200069, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-33775145

RESUMO

We carry out efforts to reproduce computational results for seven published articles and identify barriers to computational reproducibility. We then derive three principles to guide the practice and dissemination of reproducible computational research: (i) Provide transparency regarding how computational results are produced; (ii) When writing and releasing research software, aim for ease of (re-)executability; (iii) Make any code upon which the results rely as deterministic as possible. We then exemplify these three principles with 12 specific guidelines for their implementation in practice. We illustrate the three principles of reproducible research with a series of vignettes from our experimental reproducibility work. We define a novel Reproduction Package, a formalism that specifies a structured way to share computational research artifacts that implements the guidelines generated from our reproduction efforts to allow others to build, reproduce and extend computational science. We make our reproduction efforts in this paper publicly available as exemplar Reproduction Packages. This article is part of the theme issue 'Reliability and reproducibility in computational science: implementing verification, validation and uncertainty quantification in silico'.

3.
Anaesthesia ; 76(2): 238-250, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33141959

RESUMO

Intravenous lidocaine is used widely for its effect on postoperative pain and recovery but it can be, and has been, fatal when used inappropriately and incorrectly. The risk-benefit ratio of i.v. lidocaine varies with type of surgery and with patient factors such as comorbidity (including pre-existing chronic pain). This consensus statement aims to address three questions. First, does i.v. lidocaine effectively reduce postoperative pain and facilitate recovery? Second, is i.v. lidocaine safe? Third, does the fact that i.v. lidocaine is not licensed for this indication affect its use? We suggest that i.v. lidocaine should be regarded as a 'high-risk' medicine. Individual anaesthetists may feel that, in selected patients, i.v. lidocaine may be beneficial as part of a multimodal peri-operative pain management strategy. This approach should be approved by hospital medication governance systems, and the individual clinical decision should be made with properly informed consent from the patient concerned. If i.v. lidocaine is used, we recommend an initial dose of no more than 1.5 mg.kg-1 , calculated using the patient's ideal body weight and given as an infusion over 10 min. Thereafter, an infusion of no more than 1.5 mg.kg-1 .h-1 for no longer than 24 h is recommended, subject to review and re-assessment. Intravenous lidocaine should not be used at the same time as, or within the period of action of, other local anaesthetic interventions. This includes not starting i.v. lidocaine within 4 h after any nerve block, and not performing any nerve block until 4 h after discontinuing an i.v. lidocaine infusion.


Assuntos
Anestésicos Locais/administração & dosagem , Anestésicos Locais/uso terapêutico , Lidocaína/administração & dosagem , Lidocaína/uso terapêutico , Dor Pós-Operatória/prevenção & controle , Administração Intravenosa , Anestésicos Locais/efeitos adversos , Comorbidade , Consenso , Humanos , Infusões Intravenosas , Lidocaína/efeitos adversos , Bloqueio Nervoso , Segurança do Paciente , Recuperação de Função Fisiológica , Medição de Risco , Resultado do Tratamento
4.
Exp Lung Res ; 45(5-6): 135-150, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190576

RESUMO

Abrin, a highly toxic plant protein found in the seeds of Abrus precatorius plant. To date, there is no antidote against abrin intoxication. Abrin is toxic by all routes of exposure, but inhalation exposure is the most toxic of all routes. Present study was conducted to evaluate the acute inhalation toxicity of aerosolized abrin in BALB/c mice. Animals were exposed to 0.2 and 0.8LC50 doses of aerosolized abrin and evaluated at 1 and 3 day post toxin exposure. Bronchoalveolar fluid from lungs was used for evaluation of markers for lung injury. Abrin inhalation exposure caused rise in LDH activity, protein content, increase in ß-glucuronidase and myeloperoxidase activity. Increase in CRP activity, MMP-9 expression and recruitment of CD11b + inflammatory cells in lungs was also observed which was associated with severe inflammation and lung damage. Histopathological findings support the lung damage after abrin exposure. Our results indicate lung injury after single aerosol inhalation exposure, associated with excessive inflammation, oxidative stress, pulmonary edema followed by lung damage. These results could supplement treatment strategies and planning for therapeutic approaches against aerosolized abrin inhalation exposure.


Assuntos
Abrina/toxicidade , Exposição por Inalação/efeitos adversos , Pneumopatias/induzido quimicamente , Pulmão/efeitos dos fármacos , Animais , Líquido da Lavagem Broncoalveolar/química , Proteína C-Reativa/metabolismo , Antígeno CD11b/metabolismo , Catalase/metabolismo , Glucuronidase/metabolismo , Glutationa/metabolismo , L-Lactato Desidrogenase/metabolismo , Pulmão/enzimologia , Pulmão/imunologia , Pneumopatias/enzimologia , Pneumopatias/imunologia , Camundongos Endogâmicos BALB C , Ativação de Neutrófilo , Peroxidase/metabolismo
5.
Inhal Toxicol ; 30(7-8): 287-298, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30375901

RESUMO

Efficacy of two oximes treatments evaluated during inhalation of sarin vapor (LCt50, 755.9 mg/min/m3) in simulated real scenario in vivo. Majority of mice either became moribund or died within 1-2 min during exposure to multifold-lethal concentrations of sarin vapor. Protection indices were determined by exposing to sarin vapor in two sessions, 1 min exposure followed by treatments with or without HNK-102 (56.56 mg/kg, im) or 2-PAM (30 mg/kg, im) and atropine (10 mg/kg, ip), and again exposed for remaining 14 min. Protection offered by HNK-102 was found to be four folds higher compared to 2-PAM in the same toxic environment. Secondly, sub-lethal concentration of sarin vapor (0.8 × LCt50 or 605 mg/min/m3), 24 h post investigations revealed that the oximes could not reactivate brain and serum acetylcholinesterase (AChE) activity. The treatments prevented increase in protein concentration (p < .05) and macrophages infiltration compared to sarin alone group in broncho-alveolar lavage fluid. Lung histopathology showed intense peribronchial infiltration and edema with desquamating epithelial lining and mild to moderate alveolar septal infiltration in sarin and atropine groups, respectively. Noticeable peeling-off observed in epithelial lining and sporadic mild infiltration of epithelial cells at bronchiolar region in 2-PAM and HNK-102 groups, respectively. The oximes failed to reactivate AChE activity; however, the mice survived up to 6.0 × LCt50, proved involvement of non-AChE targets in sarin toxicity. Atropine alone treatment was found to be either ineffective or increased the toxicity. HNK-102, exhibited better survivability with lung protection, can be considered as a better replacement for 2-PAM to treat sarin inhalation induced poisoning.


Assuntos
Substâncias para a Guerra Química/intoxicação , Exposição por Inalação/efeitos adversos , Oximas/farmacologia , Compostos de Pralidoxima/farmacologia , Sarina/intoxicação , Acetilcolinesterase/sangue , Animais , Relação Dose-Resposta a Droga , Intoxicação por Gás/prevenção & controle , Dose Letal Mediana , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Camundongos , Oximas/química , Compostos de Pralidoxima/química , Sarina/toxicidade
6.
Drug Chem Toxicol ; 39(2): 182-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26247826

RESUMO

OBJECTIVE: The present study was planned to investigate the prophylactic efficacy of S-2(2-aminoethylamino)ethyl phenyl sulfide (DRDE-07), against topically applied SM induced pulmonary toxicity in mouse. MATERIALS AND METHODS: Animals were pretreated with S-2(2-aminoethylamino)ethyl phenyl sulfide (DRDE-07) (249.4 mg/kg by oral gavage) 30 minutes before SM exposure. The SM (6.48 mg/kg) was applied on hair clipped dorsocaudal region (percutaneous) of the animal. The animals were sacrificed on day 1, 3, 5 and 7. The biochemical changes those were observed in the bronchoalveolar lavage (BAL) fluid and lung tissue included protein, LDH, MPO, ß-glucuronidase, MMP-2, MMP-9, activated macrophages, reduced glutathione and lipid peroxidation level. RESULTS AND DISCUSSION: Pretreatment with DRDE-07 (0.2 LD50) attenuated SM-induced changes at all time point tested. BAL fluid biochemical endpoints indicated epithelial and endothelial cell damages as evidenced by increase in BAL protein, LDH level and increased number of activated macrophages. The increased myeloperoxidase activity and ß-glucuronidase level exhibited the degranulation of neutrophils due to SM toxicity in lung. The zymogrphy analysis of BAL fluid showed a significant increase in matrix metalloproteases (MMP) activity due to inflammatory cells accumulation. CONCLUSION: Thirty minutes pretreatment with DRDE-07 decreased vascular permeability reduced the inflammation and oxidative stress, hence may be recommended as a potential prophylactic agent for SM intoxication.


Assuntos
Amifostina/análogos & derivados , Substâncias para a Guerra Química/toxicidade , Lesão Pulmonar/prevenção & controle , Pulmão/efeitos dos fármacos , Gás de Mostarda/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Administração Cutânea , Administração Oral , Amifostina/administração & dosagem , Amifostina/farmacologia , Amifostina/uso terapêutico , Animais , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Feminino , Citometria de Fluxo , Glucuronidase/metabolismo , Pulmão/metabolismo , Pulmão/patologia , Lesão Pulmonar/induzido quimicamente , Lesão Pulmonar/patologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/imunologia , Camundongos , Infiltração de Neutrófilos/efeitos dos fármacos , Peroxidase/metabolismo
7.
Environ Toxicol ; 30(1): 64-73, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23929680

RESUMO

T-2 toxin is the most toxic among mycotoxins and poses a potential health hazard for both humans and animals. At high doses, T-2 toxin can cause shock-like syndrome that can result in death. We evaluated the effect of time course and route of exposure on hepatic oxidative damage in mice and it is only such study so far to compare the effects of dermal and subcutaneous exposure of T-2 toxin. Mice were exposed to 1 LD50 of T-2 toxin either by percutaneous (5.94 mg/kg body weight) or subcutaneous (1.54 mg/kg body weight) route and sacrificed at 0, 1, 3, and 7 days postexposure. Analysis of a number of serum biochemical variables, antioxidant enzymes activity, gene and protein expression by immunoblot assay showed time and route dependent effects of T-2 induced hepatic oxidative damage. Time dependent increase in protein carbonyl content and protein oxidation was seen in serum and liver. Results of our study may provide possible mechanism for developing medical countermeasures against T-2 toxin.


Assuntos
Antioxidantes/metabolismo , Fígado/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Toxina T-2/toxicidade , Administração Cutânea , Animais , Biomarcadores/sangue , Catalase/genética , Catalase/metabolismo , Feminino , Expressão Gênica/efeitos dos fármacos , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Injeções Subcutâneas , Fígado/enzimologia , Fígado/metabolismo , Camundongos , Carbonilação Proteica , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo
8.
Anaesthesia ; 67(2): 110-4, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22251104

RESUMO

We speculated that asymptomatic patients undergoing routine surgery might be at higher risk of subsequent cardiac events. We studied 183,534 patients with no prior admission for heart disease, aged 50-75 years, admitted electively for one of five operations considered medium to low risk of peri-operative cardiac morbidity, between January 1997 and December 2005. Controls were generated from linked records. Within 3 years 3444 (1.9%) patients undergoing operations had subsequent myocardial infarction/acute coronary syndrome (MI/ACS) compared with 3708 (2.0%) controls (p < 0.001). Overall 8406 (4.6%) patients undergoing surgery had MI/ACS compared with 9306 (5.1%) controls (p < 0.001). Of patients undergoing surgery, 20.2% died compared with 25.7% of controls (p < 0.001). Patients undergoing certain surgical procedures did not have a higher incidence of readmission for cardiac events, but had a general survival benefit compared with other elective hospital admissions. Assessment for surgery may represent a health benefit beyond the original surgery.


Assuntos
Doença da Artéria Coronariana/etiologia , Complicações Pós-Operatórias/etiologia , Procedimentos Cirúrgicos Operatórios/efeitos adversos , Síndrome Coronariana Aguda/epidemiologia , Síndrome Coronariana Aguda/etiologia , Síndrome Coronariana Aguda/mortalidade , Fatores Etários , Idoso , Doença da Artéria Coronariana/epidemiologia , Doença da Artéria Coronariana/mortalidade , Bases de Dados Factuais , Procedimentos Cirúrgicos Eletivos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/mortalidade , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/mortalidade , Análise de Regressão , Estudos Retrospectivos , Escócia/epidemiologia , Fatores Sexuais , Análise de Sobrevida , Procedimentos Cirúrgicos Vasculares/efeitos adversos
9.
J Environ Biol ; 33(3): 673-81, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-23029921

RESUMO

The chemical and biological warfare agents are extremely toxic in nature. They act rapidly even in very small quantities and death may occur in minutes. Hence, physical and medical protection must be provided immediately to save life or avoid serious injury. A first aid kit has thus been developed for providing immediate relief from chemical and biological warfare agents (FAKCBW) with the objective of easy detection, personal decontamination, antidote for chemical warfare agents (like nerve agents, sulphur mustard, phosgene, cyanide, radiation exposure and bacterial agents), along with basic medication aid for pain, fever and inflammation. The kit box also includes a user friendly handbook with a simple standard operating procedure. In addition, the kit is rugged to withstand normal jerks, vibration and is water-proof.


Assuntos
Antídotos/uso terapêutico , Armas Biológicas , Substâncias para a Guerra Química , Primeiros Socorros/instrumentação , Intoxicação/tratamento farmacológico , Descontaminação/instrumentação , Lesões por Radiação/prevenção & controle , Fitas Reagentes
10.
Apoptosis ; 16(2): 145-61, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21082355

RESUMO

Okadaic acid (OA) is a specific and potent protein phosphatase inhibitor and tumor promoter. The present study establishes the role of reactive oxygen species (ROS) and mitogen activated protein kinases in cell death induced by okadaic acid. The study showed that okadaic acid is cytotoxic at 10 nM with an IC50 of 100 nM in U-937 cells. The CVDE assay and mitochondrial dehydrogenase assay showed a time dependent cytotoxicity. The phase contrast visualization of the OA treated cells showed the apoptotic morphology and was confirmed with esterase staining for plasma membrane integrity. OA activated caspases-7, 9 and 3, PARP cleavage and induced nuclear damage in a time and dose dependent manner. Compromised mitochondrial membrane potential, release of cytochrome-c and apoptosis inducing factor confirms the involvement of mitochondria. A time dependent decrease in glutathione levels and a dose dependent increase in ROS with maximum at 30 min were observed. ROS scavenger-N-acetyl cysteine, mitochondrial stabilizer-cyclosporin-A, and broad spectrum caspase inhibitor Z-VAD-FMK inhibited the OA induced caspase-3 activation, DNA damage and cell death but caspase-8 inhibitor had no effect. OA activated p38 MAPK and JNK in a time dependent manner, but not ERK½. MAP kinase inhibitors SB203580, SP600125 and PD98059 confirm the role of p38 MAPK and JNK in OA induced caspase-3 activation and cell death. Over all, our results indicate that OA induces cell death by generation of ROS, and activation of p38 MAPK and JNK, and executed through mitochondrial mediated caspase pathway.


Assuntos
Apoptose , Ácido Okadáico/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Acetilcisteína/farmacologia , Clorometilcetonas de Aminoácidos/farmacologia , Antracenos/farmacologia , Fator de Indução de Apoptose/metabolismo , Western Blotting , Caspase 3/genética , Caspase 3/metabolismo , Caspase 7/genética , Caspase 7/metabolismo , Caspase 9/genética , Caspase 9/metabolismo , Linhagem Celular Tumoral , Ciclosporinas/farmacologia , Citocromos c/metabolismo , Dano ao DNA/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Flavonoides/farmacologia , Glutationa/análise , Humanos , Imidazóis/farmacologia , Immunoblotting , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Piridinas/farmacologia , Células U937 , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
11.
Environ Toxicol Pharmacol ; 76: 103333, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32062414

RESUMO

Our previous study showed that percutaneous sulfur mustard (SM) exposure induced pulmonary toxicity, which was attenuated by DRDE-07 (S-2[2-aminoethylamino] ethyl phenyl sulphide) pretreatment. The present study aimed to evaluate the protective efficacy of DRDE-07 and its analogues viz., DRDE-30 (S-2(2-aminoethyl amino)ethyl propyl sulphide) and DRDE-35 (S-2(2-aminoethyl amino)ethyl butyl sulphide) against SM. Thirty minutes before percutaneous SM (0.8 LD50) exposure, female Swiss mice were orally gavaged with DRDE-07 and its analogues(0.2 LD50). Animals were sacrificed on day 3 and 7, BAL fluid (BALF) and lung tissue were collected for biochemical, histopathological studies. As results, DRDE-07 and its analogues were beneficial in reducing the number of BALF inflammatory cells, protein level, lactate dehydrogenase (LDH) activity, myeloperoxidase (MPO) and ß-glucuronidase activity, while content of BALF and lung reduced glutathione level (GSH) were significantly protected. The pretreatment of DRDE-07 and its analogues inhibited the recruitment of inflammatory cells into the lung. The beneficial effects of DRDE-07 and its analogues were attributed to their antioxidant and anti-inflammatory activity. Among the analogues, DRDE-30 exhibited significant beneficial effects as compared to the other two compounds. These analogues may be considered as prototype candidate molecules as there is no effective antidote for SM toxicity.


Assuntos
Amifostina/análogos & derivados , Inflamação/induzido quimicamente , Pneumopatias/induzido quimicamente , Pneumopatias/prevenção & controle , Gás de Mostarda/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Amifostina/farmacologia , Animais , Anti-Inflamatórios/farmacologia , Líquido da Lavagem Broncoalveolar/química , Substâncias para a Guerra Química/toxicidade , Feminino , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Inflamação/prevenção & controle , Pulmão/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Malondialdeído , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 9 da Matriz/metabolismo , Camundongos
12.
J Pain Res ; 12: 1189-1192, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31118747

RESUMO

Peripheral nerve damage can result in neuronal hyperexcitability, resulting in neuropathic pain. Localized neuropathic pain is confined to a specific area not larger than a letter-size piece of paper. Topical analgesics are increasingly popular for the treatment of localized neuropathic pain because systemic agents for managing neuropathic pain often produce undesirable and intolerable side effects. Commonly used agents for topical use are amitriptyline, baclofen, ketamine and lidocaine; however, these agents do not always give the desired analgesic effect in some patients. We report for the first time a patient with chronic idiopathic axonal polyneuropathy and intractable localized neuropathic pain treated successfully with loperamide 5% cream. After application of loperamide 5% cream, the patient reported a complete reduction of pain within 30 mins, lasting for 2.5 hrs. Subsequently, the patient was able to reduce his daily intake of oxycodone, while using topical loperamide for pain relief. Loperamide is a nonprescription opioid agonist, commonly used against diarrhea. As a topical formulation, it is preferable over other opioids due to its low systemic bioavailability and low risk of crossing the blood-brain barrier. Peripheral upregulation and sensitization of opioid receptors at peripheral nerve endings and perhaps at other cell populations in the epidermis might be targets of topical loperamide.

13.
Toxicol In Vitro ; 22(8): 1902-8, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18854210

RESUMO

Abrin is a plant glycoprotein toxin, classified as ribosome inactivating protein (RIP) due to its property of damaging ribosomes in an irreversible manner. Many RIPs have direct DNA damaging activity. The objective of the present study was to evaluate the oxidative stress and DNA damaging potential of abrin in U937 human myeloleukemic cells. Cells were treated with abrin at IC50 of 8 ng/ml for 24h. Abrin induced a time dependent increase in reactive oxygen species and levels of antioxidant enzymes. There was significant depletion of reduced glutathione levels. DNA damage was assessed by comet assay in terms of percent head DNA, tail DNA, tail length and Olive tail moment. DNA damage was more pronounced at 4 and 8h at IC50 concentration. Abrin at 4, 8, 16 and 32 ng/ml concentration induced significant DNA damage at 4h. There was time dependent increase in levels of 8-OHdG in abrin treated cells indicating the oxidative stress mediated DNA damage. N-Acetylcysteine pretreatment at 10nM for 1h, considerably reversed the abrin induced DNA damage at 16 and 32 ng/ml. Our results clearly show oxidative DNA damage potential of abrin at low concentration.


Assuntos
Abrina/toxicidade , Dano ao DNA/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Proteínas Inativadoras de Ribossomos/toxicidade , Abrina/administração & dosagem , Acetilcisteína/farmacologia , Antioxidantes/metabolismo , Ensaio Cometa , Sequestradores de Radicais Livres/farmacologia , Glutationa/efeitos dos fármacos , Glutationa/metabolismo , Humanos , Concentração Inibidora 50 , Linfoma Difuso de Grandes Células B/metabolismo , Proteínas Inativadoras de Ribossomos/administração & dosagem , Fatores de Tempo , Células U937
14.
Indian J Physiol Pharmacol ; 52(4): 366-74, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19585753

RESUMO

The aim of the study is to demonstrate the presence of intracellular calcium store in frog ventricle based on contractures induced by 4-aminopyridine in calcium-free media. Frog-ventricular strips were subjected to field stimulation at 0.2 Hz and the force of contraction was recorded after stabilization. The preparation was then kept quiescent for some time in solutions with different sodium concentrations, containing 0 or 1 mmol/L calcium. Caffeine, 4-aminopyridine (4-AP), or tetraethylammonium chloride was then added. Frog skeletal muscle preparations were used as positive controls for the caffeine experiments. Frog ventricular preparations did not develop contractures (sustained contractions) in the presence of caffeine (25 mmol/L), while frog skeletal muscle preparations developed caffeine-induced contractures. However, 4-AP (16 mmol/L) was able to induce contractures in quiescent frog ventricular preparations, even when they were superfused with calcium-free solution. 4-AP contractures in frog ventricle were seen in the presence of nifedipine also. Amplitude of 4-AP evoked contractures in frog ventricle were much larger in low sodium (30 mmol/L) and sodium-free (sodium substituted by lithium) solutions than in normal sodium solution, suggesting that the route of extrusion of the cytosolic calcium (released from intracellular stores by 4-AP) is the sodium calcium exchanger, which gets reversed in low sodium solutions. Tetraethylammonium chloride (TEA) was not able to induce contractures in frog ventricle suggesting that the contracture evoked by 4-AP is not due to its potassium channel blocking effect. In quiescent frog skeletal muscle preparations, caffeine as well as 4-AP induced contractures in calcium-free solutions. We therefore conclude that there is a caffeine-insensitive, 4-AP sensitive intracellular calcium store in the frog ventricle.


Assuntos
4-Aminopiridina/farmacologia , Cálcio/metabolismo , Contração Miocárdica/efeitos dos fármacos , Miocárdio/metabolismo , Animais , Cafeína/farmacologia , Canais de Cálcio Tipo L/efeitos dos fármacos , Feminino , Técnicas In Vitro , Masculino , Ranidae , Compostos de Tetraetilamônio/farmacologia
16.
Cell Mol Biol (Noisy-le-grand) ; 53(5): 92-102, 2007 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-17543238

RESUMO

Ricin a glycoprotein from the Ricinus communis seeds, is known to have diverse toxic effects on cells of different visceral organs. We have studied the effect of ricin (0.5, 1.0 and 2.0 LD50) on various oxidative stress markers at 1, 3 and 7 day post exposure following i.p. administration in Swiss albino male mice. Results of this study revealed that ricin induces generation of reactive species, lipidperoxidation, DNA fragmentation and depletion of GSH. Activity of antioxidant cascade related enzyme like superoxide dismutase (SOD), glutathione peroxidase (GPx) decreased, while glutathione reductase (GR) and catalase activity increased. Superoxide dismutase and glutathione peroxidase activity was decreased significantly in liver, spleen and kidney. The decrease was more prominent on 7 day of post exposure in all the exposed doses. A significant increase in the activities of catalase was observed in plasma, liver, spleen and kidney on 7 day following ricin exposure. Glutathione reductase increased significantly as early as 24 h following 1.0 LD50 dose. Lipid peroxidation increased and non protein sulfhydryl content decreased in all the tissues at different time intervals. Total antioxidant status was reduced as early as 1 day post exposure. Nearly two fold increase was observed in DNA fragmentation following 0.5 LD50 dose of ricin on 1 day post exposure. DNA diffusion assay also indicated an early damage to DNA due to ROS. An early change in DNA fragmentation, DNA diffusion, and total antioxidant status and in the activity of various enzymes indicates that ricin produce oxidative stress by generation of reactive oxygen species as early as 24 h at a minimum dose of 0.5 LD50. Probably this is the first study which indicate that ricin induced oxidative stress at a minimum dose of 0.5 LD50.


Assuntos
Antioxidantes/metabolismo , Dano ao DNA/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ricina/farmacologia , Animais , Catalase/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Baço/efeitos dos fármacos , Baço/metabolismo , Superóxido Dismutase/metabolismo
17.
J Assoc Physicians India ; 54: 109-12, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16715612

RESUMO

AIM: Natural calamities are known to result in higher stress conditions and also result in adverse health outcomes including development of non-communicable diseases. The impact of tsunami on mental stress and prevalence of hyperglycemic conditions was assessed in a population affected by the calamity in coastal populations of southern India. METHODS: Two populations similar in demography and physical characteristics, but, one affected by tsunami were selected for a comparative study. Subjects aged 20 years or above were randomly selected (control population n = 1176; tsunami population n = 1184). Details of stress were assessed using Harvard trauma questionnaire and scores were assigned. Glucose tolerance was assessed using 2h capillary blood glucose (75gms glucose load) and diagnosis was made using WHO criteria. RESULTS: Stress score was significantly higher in tsunami population. Although the total prevalence of diabetes was similar (control - 10.0 %; tsunami population - 10.5 %) prevalence of undetected diabetes (5.7 % vs. 3.8 %; Z = 9.54, P < 0.001) and impaired glucose tolerance (9.8 % vs. 8.3 %; Z = 12.83, P < 0.001) higher in the tsunami area. Stress score was higher in women and in the young in the tsunami area. CONCLUSION: Population affected by tsunami was under high stress and also showed a high prevalence of undetected diabetes and impaired glucose tolerance.


Assuntos
Diabetes Mellitus/diagnóstico , Desastres , Hiperglicemia/etiologia , Estresse Psicológico/complicações , Adulto , Estudos de Casos e Controles , Diabetes Mellitus/epidemiologia , Feminino , Humanos , Hiperglicemia/diagnóstico , Índia/epidemiologia , Masculino , Prevalência , Inquéritos e Questionários
18.
Artigo em Inglês | MEDLINE | ID: mdl-16766833

RESUMO

BACKGROUND: Banana leaf is used in many centers in India during the care of patients with toxic epidermal necrolysis (TEN) and other extensive blistering disorders. Sepsis is an important cause of death in TEN patients and use of banana leaf may be a source of such infection. AIMS: We conducted this study to detect the bacterial flora of the banana leaf and to examine various methods of rendering the leaf aseptic. METHODS: Five pieces of banana leaf, 2 x 2 cm in size, were cultured separately in blood agar as follows: One piece was heated over a flame and one was soaked in boiling water and one was autoclaved. Methylated spirit was applied over one piece and ignited. One piece was placed on the media, 'as is.' The Petri dishes were incubated examined after 48 h. RESULTS: All the pieces except the autoclaved specimen of the leaf grew coagulase-negative staphylococci (CONS) when aseptic precautions were not maintained and aerobic spore bearers when all aseptic measures were subsequently instituted during the procedure. CONCLUSION: We recommend measures to prevent possible transmission of bacterial infection by the leaf. Autoclaved and aseptically handled banana leaves may be used to reduce chance of infection in the treatment of TEN.


Assuntos
Assepsia/métodos , Terapias Complementares/métodos , Musa , Folhas de Planta , Síndrome de Stevens-Johnson/terapia , Humanos , Folhas de Planta/microbiologia , Staphylococcus/patogenicidade
19.
Biochem Pharmacol ; 69(5): 855-65, 2005 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-15710362

RESUMO

The mechanism of ricin-induced apoptosis in human cervical cancer cell line HeLa was studied. The present study demonstrated that ricin induces apoptosis of human cervical cancer cells (HeLa) in a time dependent manner with an IC(50) for cell viability of 1 microg/ml. Ricin treatment resulted in a time dependent increase in LDH leakage, DNA fragmentation, percent apoptotic cells, generation of reactive oxygen species and depletion of intracellular glutathione levels. DNA agarose gel electrophoresis showed typical oligonucleosomal length DNA fragmentation. Additionally, DNA diffusion assay was performed to confirm DNA damage and apoptosis. Ricin activated caspase-3 as evidenced by both proteolytic cleavage of procaspase-3 into 20 and 18 kDa subunits, and increased protease activity. Caspase activity was maximum at 4h and led to the cleavage of 116 kDa poly(ADP-ribose) polymerase (PARP), resulting in the 85 kDa cleavage product. Ricin-induced caspase-3 activation also resulted in cleavage of DNA fragmentation factor-45 (DFF45/ICAD) and DFF40 or caspase-activated DNase in HeLa cells. Activation of caspase-3, cleavage of PARP and DNA fragmentation was blocked by pre-treatment with caspase-3 specific inhibitor Ac-DEVD-CHO (100 microM) and broad-spectrum caspase inhibitor Z-VAD-FMK (40 microM). Ricin-induced DNA fragmentation was inhibited by pre-treatment with PARP inhibitors 3-aminobenzamide (100 microM) and DPQ (10 microM). Our results indicate that ricin-induced cell death was mediated by generation of reactive oxygen species and subsequent activation of caspase-3 cascade followed by down stream events leading to apoptotic mode of cell death.


Assuntos
Apoptose/efeitos dos fármacos , Ricina/farmacologia , Caspase 3 , Caspases/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Glutationa/metabolismo , Células HeLa , Humanos , Estresse Oxidativo , Poli(ADP-Ribose) Polimerases/fisiologia
20.
J Environ Biol ; 26(3): 511-5, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16334290

RESUMO

Most frequently encountered freshwater cyanobacterial toxin is Microcystin-LR (MC-LR). Microcystins released from cells into water have been responsible for the death of humans, domestic and wild animals. Removal of microcystin by active carbon has been one of the best methods available so far. This study evaluates three grades of active carbon namely 40, 60 and 80 CTC for their removal efficiency of MC-LR from contaminated water. Kinetics of toxin removal was studied in time course experiments. Protection in mouse model was studied for the samples after the adsorption. Toxin quantitation was done by HPLC method. The MC-LR concentration after 24 hr treatment with 40, 60 and 80 CTC carbons were 4.8, 3.3 and 1.3 microg/ml respectively from an initial concentration of 5.2 microg/ml. Protection in mouse bioassay was seen after 48, 24 and 2 hr of adsorption time respectively for 40, 60 and 80 CTC carbons. 80 CTC carbon was found to be most efficient in removing MC-LR from contaminated water.


Assuntos
Toxinas Bacterianas/química , Carbono/química , Peptídeos Cíclicos/química , Purificação da Água/métodos , Adsorção , Animais , Bioensaio , Cromatografia Líquida de Alta Pressão , Cianobactérias/química , Estudos de Avaliação como Assunto , Feminino , Filtração/métodos , Cinética , Toxinas Marinhas , Camundongos , Microcistinas , Análise de Sobrevida , Fatores de Tempo
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