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1.
Artigo em Inglês | MEDLINE | ID: mdl-37127805

RESUMO

Ferrous sulfate is a commonly prescribed drug for prophylaxis and treatment purposes, particularly in women and adolescent girls. However, its easy availability, potential toxicity at higher doses, and vague clinical presentation make it a drug of concern when evaluating a case of poisoning. We present the case of a 28-year-old female who allegedly consumed 60 ferrous sulfate (60 mg of elemental iron in 200 mg of ferrous sulfate) tablets in a suicidal attempt. She presented with gastrointestinal disturbances on the same day to a tertiary care health facility. Investigations revealed deranged liver function tests, serum iron levels ten times the normal range, and high levels of saturated transferrin. Despite treatment, she succumbed to the poisoning 4 days after the incident. Autopsy showed features of liver failure, which was confirmed by histopathology. Chemical examination detected free ferrous and chloride ions. This fatal case of adult iron toxicity highlights the different causes of death in various stages of iron toxicity, providing a wider perspective on clinical management and aiding in the determination of the cause of death during an autopsy. This article adds a rare fatal iron poisoning case in adults to the literature, emphasizing the necessity for regulating iron tablet supplementation and raising public awareness of the toxicity of iron, which could save millions of lives.

2.
Acad Forensic Pathol ; 13(3-4): 116-121, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38298543

RESUMO

Introduction: Gas Gangrene following intramuscular injection is a rare but serious condition that can lead to morbidity and mortality. This case conveys a severe and fatal complication following intramuscular injections of diclofenac and vitamin B12 in a diabetic patient. Case Report: The patient developed pain and swelling in the left buttock after the injection of vitamin B12 and Diclofenac one on each buttock which worsened over time. He was diagnosed with gas gangrene when he presented to the emergency department. The blood culture identified Klebsiella pneumonia. The patient's condition rapidly deteriorated, leading to sepsis and acute kidney injury. Despite intensive care management, the patient succumbed five days after admission. At autopsy, gas gangrene of the left lower limb was evident on external examination. Histopathological examination confirmed the acute tubular damage in the kidney and the postmortem blood culture also grew Klebsiella pneumonia and Enterobacter cloacae. The cause of death was determined to be acute tubular necrosis as a result of sepsis due to non-clostridial gas gangrene. Conclusion: This instance of gas gangrene following trivial trauma poses a challenge for the forensic pathologist in establishing the causal association and in determining the causative organism. These are important when medical/surgical intervention is in question to be the cause of a fatal infection like gas gangrene. Ante-mortem/postmortem blood culture can aid in defining the causative organism of gas gangrene but the causal association with the alleged trauma/insult is still a challenge at autopsy. This case report addresses and tries to overcome the diagnostic challenges and dilemmas at autopsy in a case of gas gangrene.

3.
Indian J Pharm Sci ; 77(2): 170-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26009649

RESUMO

Cajanus cajan (L.) Millsp is one of the second most dietary legume crops. The leaf extracts may be used as a potential source of natural antioxidant. The ash values, extractive values, total phenolic and flavonoid content, in vitro antioxidant activity of various leaf extracts as well as anatomical investigation of Cajanus cajan were carried out. Physicochemical parameters such as total, acid-insoluble and water-soluble ash values and moisture content of the leaf powder of C. cajan were found to be 9.50%, 1.40 g/100 g, 4.15 g/100 g drug and 6.72%, respectively. Percent yield of acetone, aqueous, ethanol, ethyl acetate and chloroform leaf extracts were 9.0, 10.6, 13.75, 8.7 and 5.8 g/100 g, respectively. Significant amount of phenolic and flavonoid content were observed. The results of the antioxidant activity were found to be concentration-dependent. The IC50 values for DPPH assay determined for aqueous and ethanol extracts were 0.69 and 0.79 mg/ml, respectively. Reducing power is increased with increasing amount of concentration in both aqueous and ethanol leaf extracts. The highest hydroxyl radical scavenging activity reached up to 83.67% in aqueous and 78.75% in ethanol extracts and in phosphomolybdenum assay the aqueous extract showed strong antioxidant capacity up to 55.97 nM gallic acid equivalents/g. It was found that the aqueous extract possessed highest antioxidant activity in all the assays tested. The antioxidant characteristics of leaf extracts are possibly because of the presence of polyphenols. Microscopic study showed the presence of collenchyma, fibres, xylem, phloem, epidermis, trichomes, palisade tissue, basal sheath, pith and cortex in leaf, petiole and pulvinus.

4.
Indian J Med Paediatr Oncol ; 31(1): 33-5, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20931020

RESUMO

Secondary acute myeloid leukemia (sAML) is a rare complication following chemotherapy for osteogenic sarcoma. However, the exact offending drug is difficult to prove as there is no consistent data. It usually develops 2 years after completion of therapy. We report a case of sAML that developed within 8 months of completing the treatment. The patient was treated with cisplatin, doxorubicin and high-dose methotreaxate followed by surgery (amputation). Eight months after completion of therapy, while on follow-up, he presented with leukocytosis and thrombocytopenia and confirmed to have AML.

5.
Ann Bot ; 106(5): 663-74, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20736293

RESUMO

BACKGROUND AND AIMS: Abiotic stresses including salinity are the major constraints to crop production. In this regard, the use of thiourea (TU) in imparting salinity-stress tolerance to Indian mustard (Brassica juncea) has been demonstrated earlier. To gain an insight into the mechanism of TU action, various molecular and biochemical studies were conducted. METHODS: Microarray analysis was performed in seeds subjected to distilled water (control), 1 m NaCl, 1 m NaCl + 6·5 mm TU and 6·5 mm TU alone for 1 h. Real-time PCR validation of selected genes and biochemical studies were conducted under similar treatments at 1 h and 6 h. KEY RESULTS: The microarray analysis revealed a differential expression profile of 33 genes in NaCl- and NaCl + TU-treated seeds, most of which are established markers of stress tolerance. The temporal regulation of eight selected genes by real-time PCR indicated their early and co-ordinated induction at 1 h in NaCl + TU only. Besides, NaCl + TU-treated seeds also maintained a higher level of abscisic acid, reduced to oxidized glutathione (GSH : GSSG) ratio and activities of catalase, phenylalanine ammonia lyase and glutathione-S-transferases, as compared with that of NaCl treatment. The addition of LaCl(3) (a specific calcium-channel blocker) restricted the responses of TU both at molecular and biochemical level suggesting the possible involvement of a cytosolic calcium burst in the TU-mediated response. The TU-alone treatment was comparable to that of the control; however, it reduced the expression of some transcription factors and heat-shock proteins presumably due to the stabilization of the corresponding proteins. CONCLUSIONS: The TU treatment co-ordinately regulates different signalling and effector mechanisms at an early stage to alleviate stress even under a high degree of salinity. This also indicates the potential of TU to be used as an effective bioregulator to impart salinity tolerance under field conditions.


Assuntos
Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Mostardeira/efeitos dos fármacos , Mostardeira/metabolismo , Transdução de Sinais , Cloreto de Sódio/farmacologia , Estresse Fisiológico , Tioureia/farmacologia , Ácido Abscísico/farmacologia , Catalase/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Glutationa/metabolismo , Dissulfeto de Glutationa/metabolismo , Glutationa Transferase/metabolismo , Mostardeira/genética , Análise de Sequência com Séries de Oligonucleotídeos , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/metabolismo , Reação em Cadeia da Polimerase , Salinidade , Sementes/efeitos dos fármacos , Sementes/genética , Sementes/metabolismo
6.
Ann Bot ; 103(3): 403-10, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19033283

RESUMO

BACKGROUND AND AIMS: Large areas of the globe are becoming saline due to evapotranspiration and poor irrigation practices, and sustainability of agriculture is being seriously affected. Thiourea (TU) has been identified as an effective bioregulator imparting stress tolerance to crops. The molecular mechanisms involved in the TU-mediated response are considered in this study. METHODS: Differential display was performed in order to identify TU-modulated transcripts in Brassica juncea seeds exposed to various treatments (distilled water; 1 m NaCl; 1 m NaCl + 500 p.p.m. TU). The differential regulation of these transcripts was validated by quantitative real-time PCR. KEY RESULTS: Thiourea treatment maintained the viability of seeds exposed to NaCl for 6 h. Expression analysis showed that the transcript level of alpha, beta, gamma, delta and epsilon subunits of mitochondrial ATPase (mtATPase) varied in seeds subjected to the different treatments for 1 h: expression level was significantly altered by 1 m NaCl relative to controls; however, in the NaCl + TU treatment it reverted back in an integrated manner. Similar results were obtained from time-kinetics studies of beta and delta subunits in roots of 8-d-old seedlings. These observations were also confirmed by the mtATPase activity from isolated mitochondria. The reversal in the expression and activity profile of mtATPase through the application of a bioregulator such as TU is a novel finding for any plant system. CONCLUSIONS: The results suggest that TU treatment maintains the integrity and functioning of mitochondria in seeds as well as seedlings exposed to salinity. Thus, TU has the potential to be used as an effective bioregulator to impart salinity tolerance under field conditions, and might prove to be of high economic importance by opening new avenues for both basic and applied research.


Assuntos
Adenosina Trifosfatases/metabolismo , Mitocôndrias/enzimologia , Mostardeira/enzimologia , Salinidade , Sementes/enzimologia , Estresse Fisiológico/efeitos dos fármacos , Tioureia/farmacologia , Adenosina Trifosfatases/genética , Células Clonais , DNA Complementar/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Germinação/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mostardeira/efeitos dos fármacos , Mostardeira/embriologia , Mostardeira/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Sementes/efeitos dos fármacos , Sementes/genética , Análise de Sequência de DNA , Fatores de Tempo
7.
Acta Haematol ; 118(3): 141-5, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17804901

RESUMO

Acute leukemia presenting as cholestatic jaundice is rare. It can occur due to granulocytic sarcoma compressing the bile ducts in case of acute myeloid leukemia. Rarely, diffuse infiltration of the liver sinusoids by the leukemic blasts can present as cholestatic jaundice. We report a case of chronic myeloid leukemia in lymphoid blast cell crisis presenting with severe cholestatic jaundice due to diffuse infiltration of the liver sinusoids with lymphoblasts. This patient tolerated imatinib well and, coinciding with the hematological response, there was marked reduction in the cholestasis due to blast clearance from the hepatic sinusoids. He was subsequently treated with combination chemotherapy and achieved morphological and cytogenetic remission.


Assuntos
Antineoplásicos/administração & dosagem , Crise Blástica/tratamento farmacológico , Icterícia Obstrutiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Piperazinas/administração & dosagem , Pirimidinas/administração & dosagem , Adulto , Antineoplásicos/efeitos adversos , Benzamidas , Crise Blástica/complicações , Crise Blástica/diagnóstico , Crise Blástica/patologia , Diagnóstico Diferencial , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Humanos , Mesilato de Imatinib , Icterícia Obstrutiva/complicações , Icterícia Obstrutiva/diagnóstico , Icterícia Obstrutiva/patologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/complicações , Leucemia Mielogênica Crônica BCR-ABL Positiva/congênito , Leucemia Mielogênica Crônica BCR-ABL Positiva/diagnóstico , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patologia , Masculino , Piperazinas/efeitos adversos , Pirimidinas/efeitos adversos
8.
Radiat Environ Biophys ; 45(3): 221-9, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16850336

RESUMO

The alterations in structure and function of photosystem II (PS II) during the senescence of primary leaves of wheat seedlings have been compared with the changes induced by ultraviolet-B (UV-B) radiation in the presence or absence of photosynthetically active radiation (PAR). The results indicated that the senescence-induced loss in pigment content, thylakoid membrane integrity and carotenoid-to-chlorophyll (Car-to-Chl) energy transfer efficiency was intensified by exposure to UV-B radiation. Different parameters for the measurement of PS II activity, such as Chl a fluorescence, O2-evolution and thermoluminescence intensity, were altered during senescence and these alterations were furthered by UV-B irradiation. The damage of photosynthetic apparatus by UV-B exposure in the presence of PAR was less than the damage in absence of PAR. The activation of molecular defense mechanisms could be a factor in the alleviation of UV-B damage in the presence of PAR.


Assuntos
Senescência Celular/efeitos da radiação , Fotossíntese/fisiologia , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação , Triticum/fisiologia , Triticum/efeitos da radiação , Raios Ultravioleta , Senescência Celular/fisiologia , Relação Dose-Resposta à Radiação , Oxigênio/metabolismo , Fotossíntese/efeitos da radiação , Complexo de Proteína do Fotossistema II/fisiologia , Complexo de Proteína do Fotossistema II/efeitos da radiação , Doses de Radiação
9.
J Dairy Sci ; 85(1): 234-43, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11860116

RESUMO

Eight multiparous Holstein and four multiparous Brown Swiss (78 +/- 43 DIM) cows were used in a 4 x 4 Latin square with 28-d periods to evaluate if feeding fish oil with a source of linoleic acid (extruded soybeans) would stimulate additional amounts of conjugated linoleic acid in milk. Four treatments consisted of a control diet with a 50:50 ratio of forage to concentrate (DM basis), a control diet with 2% added fat from either menhaden fish oil or extruded soybeans, or a combination of fish oil and extruded soybeans each adding 1% fat. DM intake (24.3, 21.6, 24.5, and 22.5 kg/d, for control, fish oil, extruded soybeans, and combination diets, respectively), milk production (32.1, 29.1,34.6, and 31.1 kg/d), and milk fat content (3.51, 2.79, 3.27, and 3.14%) were lower for cows that consumed either fish oil-containing diet, especially the 2% fish oil diet. The proportion of n-3 fatty acids in milk fat increased similarly among all three fat-supplemented diets. Concentrations of transvaccenic acid (1.00, 4.16, 2.17, and 3.51 g/100 g of fatty acids) and cis-9, trans-11 conjugated linoleic acid (0.60, 2.03, 1.16, and 1.82 g/100 g of fatty acids) in milk fat increased more with fish oil than with extruded soybeans. When fed the combination diet, these fatty acids were approximately 50% higher than expected for Holsteins, whereas concentrations were similar for Brown Swiss compared with feeding each fat source separately. These data indicated that fish oil modifies ruminal or systemic functions, stimulating increased conversion of linoleic acid into transvaccenic and conjugated linoleic acids.


Assuntos
Bovinos/metabolismo , Óleos de Peixe/administração & dosagem , Ácido Linoleico/análise , Lipídeos/análise , Leite/química , Ração Animal , Animais , Bovinos/fisiologia , Ácidos Graxos/análise , Ácidos Graxos Ômega-3/administração & dosagem , Feminino , Ácido Linoleico/administração & dosagem , Glycine max/química
10.
J Dairy Sci ; 84(10): 2144-51, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11699444

RESUMO

Milk was collected from eight multiparous Holstein and four multiparous Brown Swiss cows that were distributed into four groups and arranged in a randomized complete block design with four 4-wk periods. The four treatments included a control diet of a 50:50 ratio of forage-to-concentrate; a fish oil diet of the control diet with 2% (on dry matter basis) added fat from menhaden fish oil; a fish oil with extruded soybean diet of the control diet with 1% (on dry matter basis) added fat from menhaden fish oil and 1% (on dry matter basis) added fat from extruded soybeans; and an extruded soybean diet of the control diet with 2% (on dry matter basis) added fat from extruded soybeans. Milk from cows fed control, fish oil, fish oil with extruded soybean, and extruded soybean diets contained 3.31, 2.58, 2.94, and 3.47% fat, respectively. Concentrations of conjugated linoleic acid in milk were highest in the fish oil (2.30 g/100 g of fatty acids) and fish oil with extruded soybean (2.17 g/100 g of fatty acids) diets compared with the control (0.56 g/100 g fatty acids) diet. Milk, cream, butter, and buttermilk from the fish oil, fish oil with extruded soybean, and extruded soybean diets had higher concentrations of transvaccenic acid and unsaturated fatty acids compared with the controls. Butter made from the extruded soybean diet was softest compared with all treatments. An experienced sensory panel found no flavor differences in milks or butters.


Assuntos
Manteiga/análise , Bovinos/fisiologia , Óleos de Peixe/administração & dosagem , Glycine max , Leite/química , Ração Animal , Animais , Bovinos/metabolismo , Gorduras/análise , Ácidos Graxos Insaturados/análise , Feminino , Ácido Linoleico/análise , Distribuição Aleatória , Paladar
11.
Kidney Int ; 57(4): 1460-71, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10760082

RESUMO

BACKGROUND: : Cellular proliferation is a key factor in the enlargement of renal cysts in autosomal dominant polycystic kidney disease (ADPKD). We determined the extent to which adenosine 3':5'-cyclic monophosphate (cAMP) may regulate the in vitro proliferation of cyst epithelial cells derived from human ADPKD cysts. METHODS: : Epithelial cells from cysts of individuals with ADPKD and from normal human kidney cortex (HKC) of individuals without ADPKD were cultured. The effects of agonists and inhibitors on the rate of cellular proliferation and the activation of extracellular signal-regulated kinase (ERK1/2) were determined. RESULTS: : 8-Br-cAMP (100 micromol/L) stimulated the proliferation of cells from eight different ADPKD subjects to 99.0% above baseline; proliferation was inhibited by protein kinase A (PKA) antagonists H-89 (97%) and Rp-cAMP (90%). Forskolin (10 micromol/L), which activates adenylyl cyclase, increased proliferation 124%, and receptor-mediated agonists arginine vasopressin, desmopressin, secretin, vasoactive intestinal polypeptide, and prostaglandin E2 stimulated proliferation 54.2, 56.3, 46.7, 37.1, and 48.3%, respectively. The mitogen extracellular kinase (MEK) inhibitor PD98059 completely inhibited ADPKD cell proliferation in response to cAMP agonists, but genistein, a receptor tyrosine kinase inhibitor, did not block cAMP-dependent proliferation. cAMP agonists increased the activity of ERK above control levels within five minutes. In contrast to ADPKD, proliferation and ERK activity of cells derived from normal HKC were not stimulated by cAMP agonists, although electrogenic Cl- secretion was increased by these agonists in both ADPKD and HKC cell monolayers. CONCLUSIONS: : We conclude that cAMP agonists stimulate the proliferation of ADPKD but not HKC epithelial cells through PKA activation of the ERK pathway at a locus distal to receptor tyrosine kinase. We suggest that the adenylyl cyclase signaling pathway may have a unique role in determining the rate of cyst enlargement in ADPKD through its actions to stimulate cellular proliferation and transepithelial solute and fluid secretion.


Assuntos
AMP Cíclico/farmacologia , Rim/patologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Rim Policístico Autossômico Dominante/patologia , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Impedância Elétrica , Ativação Enzimática/fisiologia , Células Epiteliais/enzimologia , Células Epiteliais/patologia , Células Epiteliais/fisiologia , Humanos , Rim/enzimologia , Rim/fisiopatologia , Córtex Renal/citologia , Córtex Renal/fisiologia , Rim Policístico Autossômico Dominante/enzimologia , Rim Policístico Autossômico Dominante/fisiopatologia
12.
Mol Carcinog ; 25(4): 262-72, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10449033

RESUMO

Exposure of mammalian cells to ultraviolet (UV) light and other DNA-damaging agents triggers the UV response which is characterized by induction of a large number of genes including c-fos, c-jun, and the genes for DNA repair enzymes and cell-cycle regulatory proteins such as p21 WAF1 and p53. Upon DNA damage, the p53 tumor suppressor protein transmits signals to restrict cell-cycle progression, thereby allowing time for DNA repair to occur. Cells also respond to genotoxic stress by activation of the jun N-terminal kinase (JNK)/stress-activated protein kinase pathway. In this report we investigated the effects of modulation of the level of wild-type and mutant p53 protein on basal and UV-inducible JNK activity. We used the A1-5 rat fibroblast cell line, which contains a p53 gene coding for a temperature-sensitive p53 protein, which allows us to regulate the relative level of wild-type and mutant p53 protein produced in a cell. We measured the relative levels of JNK activity in sham-irradiated and UV-irradiated cells by using the immune complex kinase assay and then computed the fold induction of JNK after UV exposure. We demonstrated that cells expressing p53 protein in the wild-type conformation (when grown at 32 degrees C) exhibited a very low level of JNK activity that was induced 14- to 16-fold by UVC irradiation. When cells were grown at 37 degrees C or 39 degrees C to express predominantly mutant p53 protein, basal JNK activity was significantly higher than at 32 degrees C. UVC irradiation of cells expressing mutant p53 protein resulted in JNK activation, although the overall fold-induction was only two-fold because JNK1 activity was already high in the sham-treated controls. UVB irradiation also induced JNK1 activity, although we again observed a relatively high level of basal JNK activity in sham-irradiated cells expressing mutant p53 protein compared with cells expressing wild-type p53. Control experiments confirmed that JNK1 basal activity was not affected by temperature alone. Western blot analysis of cell extracts indicated that expression of p21 WAF protein was significantly higher in cells expressing wild-type p53 protein and was associated with low basal levels of JNK1 activity. In contrast, cells expressing mutant p53 protein and very low levels of p21 WAF1 protein were found to have a higher level of basal JNK1 activity. We also observed a reduced ability to induce JNK1 after UV irradiation of several other cell lines with p53-mutant or p53-null genotypes. Our results provide evidence for a novel connection between p53 status and the basal level of JNK1, a critical enzyme in the stress-activated protein kinase family. In addition, these studies suggest that the presence of mutant p53 protein in a cell not only affects basal activity of JNK1 but also affects the ability of a cell to respond to UV-induced stress by transmitting signals via induction or activation of the JNK1 cascade.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Genes p53 , Proteínas Quinases Ativadas por Mitógeno , Mutação , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/biossíntese , Linhagem Celular , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/metabolismo , Indução Enzimática/efeitos da radiação , Fibroblastos/enzimologia , Fibroblastos/efeitos da radiação , Proteínas Quinases JNK Ativadas por Mitógeno , Queratinócitos/enzimologia , Queratinócitos/efeitos da radiação , Camundongos , Ratos , Transdução de Sinais , Proteína Supressora de Tumor p53/metabolismo , Raios Ultravioleta
13.
Oncogene ; 16(11): 1501-5, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9525748

RESUMO

Jun N-terminal kinase (JNK1) is a member of a family of stress-activated protein kinases which are activated by many forms of stress including UV radiation, resulting in the phosphorylation of c-Jun, ATF-2, Elk-1 and p53. As UV-B radiation is mainly responsible for ultraviolet (UV)-induced skin cancers, we chose to elucidate JNK1 activation in keratinocytes which represent a UV-relevant cell system. We have demonstrated rapid activation of JNK1 in a keratinocyte cell line, C50, in response to multiple doses of UV-B irradiation. JNK1 activation occurred within 1 min, peaked by 10 min and returned to near basal levels within 2 h following the UV-B treatments. Our data provide the first evidence to show that keratinocytes do respond to multiple doses of the physiologically relevant UV-B radiation through rapid activation of the JNK1 pathway.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Epiderme/efeitos da radiação , Queratinócitos/efeitos da radiação , Proteínas Quinases Ativadas por Mitógeno , Raios Ultravioleta , Linhagem Celular Transformada , Relação Dose-Resposta à Radiação , Ativação Enzimática , Células Epidérmicas , Epiderme/enzimologia , Proteínas Quinases JNK Ativadas por Mitógeno , Queratinócitos/enzimologia
14.
Eur J Biochem ; 153(3): 509-14, 1985 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-3841062

RESUMO

We have partially purified the CO2 reductase, present in green potato tuber chloroplasts, as a latent form. Illumination of the chloroplasts in the absence of substrate, bicarbonate, activated the enzyme, which could then be obtained in soluble forms. Purification of the enzyme was achieved by (NH4)2SO4 fractionation (0-30%) and adsorption and elution from a DEAE-Sephadex A-50 column. The final preparation showed 15-fold purification and 50% recovery of the activity. The pH optimum for CO2 reductase was 8.0. Hepes and Tricine buffers showed maximum activity whereas Tris/phosphate or borate failed to show any activity. The enzyme reaction was sensitive to the presence of metal ions like Fe3+, Hg2+, Cu2+, Mo6+ and Zn2+, however, a threefold activation was observed with Fe2+. The metal requirement for CO2 reductase was evident from the observed inhibition by metal chelators like o-phenanthroline, alpha, alpha'-dipyridyl, bathocuproine, 8-hydroxyquinoline etc. Out of these o-phenanthroline was the strongest inhibitor and its concentration for 50% inhibition was 40 microM. The presence of Fe2+ ions in the reaction mixture protected the enzyme from heat denaturation upto 50 degrees C. Maximum enzyme activity was observed at 15 degrees C. The enzyme activity showed a 30-s lag period and the maximum was reached in 90 s. Supplementation of sodium dithionite in the reaction activated enzyme activity threefold, suggesting involvement of dithiol groups in the catalytic activity. There was strong inhibition by -SH inhibitors like 5,5'-dithiobis(2-nitrobenzoic acid) and N-ethylmaleimide and -SH reagents like dithiothreitol, 2-mercaptoethanol and cysteine. Various nucleotide coenzyme tried inhibited the enzyme strongly.


Assuntos
Aldeído Oxirredutases/isolamento & purificação , Cloroplastos/enzimologia , Complexos Multienzimáticos , Aldeído Oxirredutases/metabolismo , Ativação Enzimática/efeitos da radiação , Concentração de Íons de Hidrogênio , Luz , Metais/farmacologia , Plantas/enzimologia , Temperatura
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