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2.
Neurochirurgie ; 68(6): 589-594, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35963712

RESUMO

OBJECTIVE: Glibenclamide, Sulfonylurea receptor 1 antagonist, reduces brain edema after cerebral hemorrhage. However, the effects of glibenclamide on microglial activation and inflammatory cell infiltration after cerebral hemorrhage are unclear. The present study investigated the effect of glibenclamide on microglial activation and inflammatory cell infiltration in a rat cerebral hemorrhage model. METHODS: A collagenase intracerebral injection model was used to cause cerebral hemorrhage in rats. After injury, glibenclamide was continuously administered at 1.0µL/h for 24hours. We evaluated hematoma volume, brain edema, expression of ABCC8, galectin-3 and CD11b, and anti-Iba-1 antibody staining. RESULTS: Glibenclamide significantly reduced water content. Meanwhile, glibenclamide significantly reduced expression of galectin-3 and CD11b in the cerebral cortex and putamen on the bleeding side. Immunohistochemical staining confirmed that glibenclamide attenuated activation of microglia around the hematoma. CONCLUSIONS: Glibenclamide reduced microglial activation and infiltration of inflammatory cells, resulting in amelioration of cerebral edema.


Assuntos
Edema Encefálico , Animais , Ratos , Edema Encefálico/tratamento farmacológico , Edema Encefálico/etiologia , Hemorragia Cerebral/tratamento farmacológico , Galectina 3 , Glibureto/farmacologia , Glibureto/uso terapêutico , Hematoma , Microglia
3.
Pharmazie ; 76(2): 114-118, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33714289

RESUMO

Introduction: Considering the physique of the Japanese population, the standard daily vancomycin dose of 2 g/day and doses ≥ 3 g/day are high in terms of dose per body weight. Studies have reported that administering high-dose vancomycin to achieve a high target trough concentration has been associated with nephrotoxicity. The risk of high-dose vancomycin-associated nephrotoxicity is believed to be exceptionally high for Japanese patients because of their relatively low body weights, but data on the population is lacking. In this retrospective study, we aimed to evaluate risk factors associated with nephrotoxicity in Japanese patients treated with vancomycin. Methods: We examined the medical records of 107 Japanese patients who received vancomycin (3 to 4 g/day). They were divided into two groups based on the presence or absence of nephrotoxicity, and their demographics and clinical characteristics were compared. Results : The incidence of nephrotoxicity in patients receiving high-dose vancomycin was 13%. Age (≥ 60 years) and concurrent use of piperacillin/tazobactam were independent risk factors for vancomycin-associated nephrotoxicity (P = 0.027 and 0.017, respectively). Conclusions : We conclude that the nephrotoxicity risk of high-dose vancomycin in Japanese patients is not excessively high when administered within the confines of a therapeutic drug-monitoring program. However, special care must be taken with patients who are older or on concurrent piperacillin/tazobactam therapy.


Assuntos
Injúria Renal Aguda/induzido quimicamente , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Vancomicina/administração & dosagem , Vancomicina/toxicidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Japão , Rim/efeitos dos fármacos , Rim/lesões , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco
4.
Neurogastroenterol Motil ; 28(7): 1027-36, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26896291

RESUMO

BACKGROUND: This study aimed to examine the effects of Lactobacillus casei strain Shirota (LcS) on gut-brain interactions under stressful conditions. METHODS: Three double-blind, placebo-controlled trials were conducted to examine the effects of LcS on psychological and physiological stress responses in healthy medical students under academic examination stress. Subjects received LcS-fermented milk or placebo daily for 8 weeks prior to taking a national standardized examination. Subjective anxiety scores, salivary cortisol levels, and the presence of physical symptoms during the intervention were pooled and analyzed. In the animal study, rats were given feed with or without LcS for 2 weeks, then submitted to water avoidance stress (WAS). Plasma corticosterone concentration and the expression of cFos and corticotropin releasing factor (CRF) in the paraventricular nucleus (PVN) were measured immediately after WAS. In an electrophysiological study, gastric vagal afferent nerve activity was monitored after intragastric administration of LcS to urethane-anesthetized rats. KEY RESULTS: Academic stress-induced increases in salivary cortisol levels and the incidence rate of physical symptoms were significantly suppressed in the LcS group compared with the placebo group. In rats pretreated with LcS, WAS-induced increases in plasma corticosterone were significantly suppressed, and the number of CRF-expressing cells in the PVN was reduced. Intragastric administration of LcS stimulated gastric vagal afferent activity in a dose-dependent manner. CONCLUSIONS & INFERENCES: These findings suggest that LcS may prevent hypersecretion of cortisol and physical symptoms under stressful conditions, possibly through vagal afferent signaling to the brain and reduced stress reactivity in the PVN.


Assuntos
Encéfalo/metabolismo , Trato Gastrointestinal/metabolismo , Lacticaseibacillus casei , Modelos Animais , Probióticos/uso terapêutico , Estresse Psicológico/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Produtos Fermentados do Leite , Método Duplo-Cego , Feminino , Trato Gastrointestinal/efeitos dos fármacos , Humanos , Hidrocortisona/metabolismo , Masculino , Probióticos/farmacologia , Ratos , Ratos Endogâmicos F344 , Saliva/efeitos dos fármacos , Saliva/metabolismo , Estresse Psicológico/tratamento farmacológico , Estresse Psicológico/psicologia , Nervo Vago/efeitos dos fármacos , Nervo Vago/fisiologia , Adulto Jovem
5.
Benef Microbes ; 7(2): 153-6, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26689231

RESUMO

This pilot study investigated the effects of the probiotic Lactobacillus casei strain Shirota (LcS) on psychological, physiological, and physical stress responses in medical students undertaking an authorised nationwide examination for promotion. In a double-blind, placebo-controlled trial, 24 and 23 healthy medical students consumed a fermented milk containing LcS and a placebo milk, respectively, once a day for 8 weeks until the day before the examination. Psychophysical state, salivary cortisol, faecal serotonin, and plasma L-tryptophan were analysed on 5 different sampling days (8 weeks before, 2 weeks before, 1 day before, immediately after, and 2 weeks after the examination). Physical symptoms were also recorded in a diary by subjects during the intervention period for 8 weeks. In association with a significant elevation of anxiety at 1 day before the examination, salivary cortisol and plasma L-tryptophan levels were significantly increased in only the placebo group (P<0.05). Two weeks after the examination, the LcS group had significantly higher faecal serotonin levels (P<0.05) than the placebo group. Moreover, the rate of subjects experiencing common abdominal and cold symptoms and total number of days experiencing these physical symptoms per subject were significantly lower in the LcS group than in the placebo group during the pre-examination period at 5-6 weeks (each P<0.05) and 7-8 weeks (each P<0.01) during the intervention period. Our results suggest that the daily consumption of fermented milk containing LcS may exert beneficial effects preventing the onset of physical symptoms in healthy subjects exposed to stressful situations.


Assuntos
Ansiedade/prevenção & controle , Produtos Fermentados do Leite/análise , Lacticaseibacillus casei/metabolismo , Leite/microbiologia , Animais , Ansiedade/metabolismo , Ansiedade/fisiopatologia , Ansiedade/psicologia , Método Duplo-Cego , Feminino , Fermentação , Humanos , Masculino , Leite/metabolismo , Probióticos/metabolismo , Estresse Fisiológico , Estudantes de Medicina/psicologia , Triptofano/metabolismo , Adulto Jovem
7.
Eur J Clin Microbiol Infect Dis ; 34(2): 261-6, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25142803

RESUMO

Reports have detailed the increasing use of spinal instrumentation in the treatment of pyogenic vertebral osteomyelitis, with the aims of achieving a lower pseudoarthrosis rate and restoring spinal alignment. However, controversy remains over the use of instrumentation in the presence of active infection because of concerns about increased bacterial adherence and biofilm formation on the metallic implant surface. Fourteen consecutive patients were followed who were diagnosed as having pyogenic vertebral osteomyelitis and underwent surgery with spinal instrumentation with iodine-containing surfaces that could be directly supported to existing titanium implants. Bone-cage interfaces and implant-related complications after surgery were evaluated. The white blood cell (WBC) count and C-reactive protein (CRP) level were analyzed during the follow-up period. To confirm the influence of iodine release from the implant, thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were also examined. The infection subsided in all 14 patients. Both WBC counts and CRP levels returned to normal ranges by the final follow-up. One patient showed a lucent area around the screw and two patients showed lucencies inside the cage. However, no cage dislocations, cage migrations, or screw pull-outs were noted, and all patients' FT3, FT4, and TSH levels were within normal ranges during the follow-up period. We demonstrated the efficacy of iodine-supported titanium implants in the management of pyogenic vertebral osteomyelitis. No cytotoxicity or adverse effects were noted in this series.


Assuntos
Iodo/uso terapêutico , Osteomielite/cirurgia , Próteses e Implantes , Infecções Relacionadas à Prótese/prevenção & controle , Coluna Vertebral/cirurgia , Titânio/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Animais , Proteína C-Reativa/análise , Feminino , Humanos , Leucócitos , Masculino , Pessoa de Meia-Idade , Osteomielite/microbiologia , Infecções Relacionadas à Prótese/microbiologia , Coluna Vertebral/microbiologia , Supuração
8.
Oral Dis ; 21(3): 361-72, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25180458

RESUMO

OBJECTIVES: The characteristics of cell populations extracted from oral mucosal non-epithelial tissues and their ability to differentiate were evaluated in vitro as a potential source of cells for mandibular and corneal regeneration. MATERIALS AND METHODS: Oral mucosal non-epithelial cells (OMNECs) were extracted from tissue samples and were studied by flow cytometry and RT-PCR. Cells differentiating into osteoblasts, adipocytes, chondrocytes, neurocytes, or keratocytes were characterized by RT-PCR and cell staining. RESULTS: OMNECs expressed CD44, CD90, CD105, CD166, and STRO-1 antigens, which are markers for mesenchymal stem cells. In addition, Oct3/4, c-Myc, Nanog, KLF4, and Rex, which are expressed by embryonic or pluripotent stem cells, were detected by RT-PCR. Expression of CD49d, CD56, and PDGFRα, proteins closely associated with the neural crest, was observed in OMNECs, as was expression of Twist1, Sox9, Snail1 and Snail2, which are early neural crest and neural markers. Specific differentiation markers were expressed in OMNECs after differentiation into osteoblasts, adipocytes, chondrocytes, or keratocytes. CONCLUSIONS: Populations of OMNECs may contain both mesenchymal stem cells and neural crest origin cells and are a potential cell source for autologous regeneration of mandibular or corneal stroma.


Assuntos
Antígenos CD/metabolismo , Expressão Gênica , Células-Tronco Mesenquimais/citologia , Mucosa Bucal/citologia , Fatores de Transcrição/metabolismo , Adipócitos/metabolismo , Adulto , Antígenos CD/genética , Antígenos de Superfície/genética , Diferenciação Celular , Células Cultivadas , Condrócitos/metabolismo , Produtos do Gene rex/genética , Humanos , Queratinócitos/metabolismo , Fator 4 Semelhante a Kruppel , Masculino , Células-Tronco Mesenquimais/fisiologia , Pessoa de Meia-Idade , Proteína Homeobox Nanog/genética , Osteoblastos/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Fatores de Transcrição/genética
10.
Mol Oral Microbiol ; 28(5): 379-91, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23734737

RESUMO

Streptococcus gordonii is a commensal gram-positive bacterium that resides in the human oral cavity, and is one of the most common causes of infective endocarditis (IE). Bacterial surface molecules play an important role in establishing IE, and several S. gordonii proteins have been implicated in binding to host cells during the establishment of IE. In this study, we identified a putative lipoprotein, peptidyl-prolyl cis/trans isomerase (PpiA), and clarified its role in evasion of phagocytosis by macrophages. Attenuation of the gene encoding prolipoprotein diacylglyceryl transferase (Lgt) altered the localization of PpiA from the cell surface to the culture supernatant, indicating that PpiA is lipid-anchored in the cell membrane by Lgt. Both human and murine macrophages showed higher phagocytic activity towards ppiA and lgt mutants than the wild-type, indicating that the presence of PpiA suppresses phagocytosis of S. gordonii. Human macrophages treated with dextran sulfate had significantly impaired phagocytosis of S. gordonii, suggesting that class A scavenger receptors in human macrophages are involved in the phagocytosis of S. gordonii. These results provide evidence that S. gordonii lipoprotein PpiA plays an important role in inhibiting phagocytic engulfment and in evasion of the host immune response.


Assuntos
Macrófagos/microbiologia , Peptidilprolil Isomerase/imunologia , Fagocitose/imunologia , Streptococcus gordonii/enzimologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Linhagem Celular Tumoral , Células Cultivadas , Sulfato de Dextrana/farmacologia , Inativação Gênica , Humanos , Evasão da Resposta Imune/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/microbiologia , Lipídeos de Membrana/genética , Lipídeos de Membrana/imunologia , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/imunologia , Camundongos , Mutação/genética , Peptidilprolil Isomerase/genética , Fagocitose/efeitos dos fármacos , RNA Interferente Pequeno , Receptores Depuradores Classe A/imunologia , Streptococcus gordonii/genética , Transferases/genética , Transferases/imunologia
12.
Oncogene ; 31(44): 4667-76, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22249260

RESUMO

Anaplastic lymphoma kinase (ALK) was originally identified from a rare subtype of non-Hodgkin's lymphomas carrying t(2;5)(p23;q35) translocation, where ALK was constitutively activated as a result of a fusion with nucleophosmin (NPM). Aberrant ALK fusion proteins were also generated in inflammatory fibrosarcoma and a subset of non-small-cell lung cancers, and these proteins are implicated in their pathogenesis. Recently, ALK has been demonstrated to be constitutively activated by gene mutations and/or amplifications in sporadic as well as familial cases of neuroblastoma. Here we describe another mechanism of aberrant ALK activation observed in a neuroblastoma-derived cell line (NB-1), in which a short-form ALK protein (ALK(del2-3)) having a truncated extracellular domain is overexpressed because of amplification of an abnormal ALK gene that lacks exons 2 and 3. ALK(del2-3) was autophosphorylated in NB-1 cells as well as in ALK(del2-3)-transduced cells and exhibited enhanced in vitro kinase activity compared with the wild-type kinase. ALK(del2-3)-transduced NIH3T3 cells exhibited increased colony-forming capacity in soft agar and tumorigenicity in nude mice. RNAi-mediated ALK knockdown resulted in the growth suppression of ALK(del2-3)-expressing cells, arguing for the oncogenic role of this mutant. Our findings provide a novel insight into the mechanism of deregulation of the ALK kinase and its roles in neuroblastoma pathogenesis.


Assuntos
Neuroblastoma/enzimologia , Neuroblastoma/genética , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Quinase do Linfoma Anaplásico , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Retículo Endoplasmático/enzimologia , Retículo Endoplasmático/metabolismo , Ativação Enzimática/genética , Ordem dos Genes , Humanos , Camundongos , Células NIH 3T3 , Neuroblastoma/metabolismo , Pirimidinas/farmacologia , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Deleção de Sequência
14.
IEEE Comput Graph Appl ; 31(5): 43-53, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-24808190

RESUMO

Current computer-aided engineering systems use numerical-simulation methods mainly as offline verification tools to reject designs that don't satisfy the required constraints, rather than as tools to guide users toward better designs. However, integrating real-time finite element method (FEM) into interactive geometric modeling can provide user guidance. During interactive editing, real-time feedback from numerical simulation guides users toward an improved design without tedious trial-and-error iterations. Careful reuse of previous computation results, such as meshes and matrices, on the basis of speed and accuracy trade-offs, have helped produce fast FEM analysis during interactive editing. Several 2D example applications and informal user studies show this approach's effectiveness. Such tools could help nonexpert users design objects that satisfy physical constraints and help those users understand the underlying physical properties.

15.
Methods Find Exp Clin Pharmacol ; 32(7): 475-80, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21069098

RESUMO

Cerebral salt wasting (CSW) frequently occurs concomitantly with an aneurysmal subarachnoid hemorrhage (SAH). CSW induces excessive natriuresis and osmotic diuresis, and reduces the total volume of blood. We previously reported that a rat model with SAH induced by endovascular puncture (EP) exhibited CSW. Therefore, we investigated the relationship between the spread of bleeding in the subarachnoid space and the intensity of CSW. We also investigated the development of CSW in different SAH models. SAH was induced by EP or by 0.3 mL of blood injection (BI) into the cisterna magna. To evaluate the occurrence of CSW, urine was cumulatively collected at the onset of SAH to 6 h later and analyzed for sodium (Na) excretion. SAH was classified from grade 1 (no bleeding) to grade 4 (severe bleeding) based on the spread of bleeding in the subarachnoid space. In the EP model (SAH grade > 2) as the SAH grade increased, the volume of urine and Na excretion also significantly increased. Although the BI model rats exhibited SAH of grade 4, the volume of urine and Na excretion did not change. Therefore, our conclusion is that the spread of bleeding in the subarachnoid space may not cause CSW.


Assuntos
Hiponatremia/etiologia , Hemorragia Subaracnóidea/fisiopatologia , Desequilíbrio Hidroeletrolítico/fisiopatologia , Animais , Sangue , Cisterna Magna , Modelos Animais de Doenças , Masculino , Natriurese , Osmose , Ratos , Ratos Wistar , Hemorragia Subaracnóidea/complicações , Urinálise , Desequilíbrio Hidroeletrolítico/etiologia
16.
Clin Nephrol ; 73(5): 398-402, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20420802

RESUMO

Rotavirus (RV) is a common pathogen that causes acute gastroenteritis in childhood. Some cases with RV infection also have prerenal renal failure induced by dehydration associated with vomiting and diarrhea. Here, we report 4 patients with RV infection who developed postrenal renal failure induced by urinary tract obstruction with uroammoniac calculi or crystals. The patients did not have metabolic disorders or abnormalities of the urinary tract, and increased urinary excretion of uric acid was not recognized at discharge. In addition, no abnormalities in the uric acid transporter (URAT1) were found in any of the patients. Uric acid stone formation was considered to have originated from the low pH caused by dehydration and the increase of urinary uric acid excretion from damaged cells.


Assuntos
Injúria Renal Aguda/virologia , Gastroenterite/complicações , Cálculos Renais/etiologia , Infecções por Rotavirus/complicações , Injúria Renal Aguda/diagnóstico , Injúria Renal Aguda/terapia , Feminino , Gastroenterite/terapia , Gastroenterite/virologia , Humanos , Lactente , Cálculos Renais/diagnóstico , Cálculos Renais/terapia , Masculino , Infecções por Rotavirus/diagnóstico , Infecções por Rotavirus/terapia
17.
Aktuelle Urol ; 41 Suppl 1: S20-3, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20094946

RESUMO

We evaluated clinical efficacies of transvaginal mesh (TVM) reconstruction alone and those concomitant with a TVT/TOT sling for the treatment of pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Between January 2006 and February 2007, 138 female patients with POP underwent TVM reconstruction. The mean age was 66.6 years (range: 52-84). Fourteen individuals were qualified as grade II in the POP quantification (POP-Q) system, 85 and 39 were grades III and IV, respectively. One hundred and seventeen of 138 (85 %) cases showed SUI. Twenty-one patients without SUI underwent TVM alone, and 117 cases with SUI underwent TVM concomitant with TVT/TOT sling. Mean operation time and intra-operative bleeding was 79 min (range: 25-177) and 74 ml (range: 10-429), respectively. Mean follow-up period is 5.3 months (range: 1-14). The vaginal prolapses were cured (grade 0) in 129 cases (93 %) after the surgery. Total inter-national prostate symptom score (IPSS), its QOL score, International Consultation on Incontinence Questionnaires Short Form (ICIQ-SF) significantly improved (from 12.6 to 3.9; p < 0.0001, from 5.0 to 1.0; p < 0.0001, and from 6.1 to 2.5; p < 0.01, respectively). Six of 21 cases (29%) who underwent TVM alone showed postoperative de-novo SUI. In contrast, 116 cases (99%) who underwent TVM concomitant with TVT/TOT, experienced a cure of SUI. Maximum flow rate did not change postoperatively in the both groups. In conclusion, the short-term efficacies of TVM reconstruction for POP are excellent, and a concomitant TVT/TOT sling prevents postoperative SUI.


Assuntos
Colposcopia/métodos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Slings Suburetrais , Telas Cirúrgicas , Incontinência Urinária por Estresse/cirurgia , Prolapso Uterino/cirurgia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade , Satisfação do Paciente , Complicações Pós-Operatórias/etiologia , Desenho de Prótese , Qualidade de Vida
18.
Pathobiology ; 76(5): 221-6, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19816081

RESUMO

OBJECTIVE: IgA nephropathy (IgA-N) frequently leads to progressive renal failure, thus estimation of the degree of progression is important for patient management. Autophagy is a mechanism that facilitates clearance of waste products to preserve renal function. The aim of this study was to assess autophagy in podocytes in children with progressive IgA-N at initial diagnosis by electron microscopy and investigate the relationship between the types of autophagy and severity of the disease. METHODS: Renal biopsies from 16 children with established progressive IgA-N were examined by light and transmission electron microscopy with reference to autophagy types in the podocytes and histopathological diagnosis of IgA-N. RESULTS: Two autophagy types were found. Type I rarely transformed to autophagic vacuoles and did not dissolve, thus possibly impairing cell function. However, type II frequently transformed to autophagosomes and autophagic vacuoles thus facilitating protein and lipid clearance. Of the 16 children studied, 8 (50%) with type I autophagy at initial diagnosis showed focal proliferative glomerulosclerosis (GN) of mild type (3 cases, 37.5%), mild/moderate type (2 cases, 25%) and moderate type (3 cases, 37.5%). In contrast, the remaining 8 children with type II autophagy at initial diagnosis showed focal proliferative GN of mild type in 7 (87.5%) and mild/moderate type in 1 (12.5%) case. CONCLUSION: In IgA-N children, the occurrence of type I autophagy is correlated with histopathologically more progressive disease, possibly reflecting a tendency to a poorer prognosis.


Assuntos
Autofagia/fisiologia , Glomerulonefrite por IGA/patologia , Podócitos/ultraestrutura , Adolescente , Criança , Feminino , Humanos , Masculino , Microscopia Eletrônica de Transmissão
19.
Oral Microbiol Immunol ; 24(6): 485-92, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19832801

RESUMO

INTRODUCTION: Hydrogen sulfide is responsible for lysis of red blood cells and is a major compound for oral malodor. To clarify the production mechanism of hydrogen sulfide in Prevotella intermedia, we found an L-cysteine desulfhydrase gene (lcs) homologue on the genome database of P. intermedia ATCC25611 and characterized its gene product. METHODS: The lcs gene homologue cloned into pGEX6p-1 vector was expressed in Escherichia coli and purified. Lcs activity was assayed by detection of the reaction products (hydrogen sulfide and pyruvate) or its derivatives from L-cysteine. Site-directed mutagenesis was used to convert an amino acid of the Lcs molecule. RESULTS: The purified lcs gene product catalysed the degradation of L-cysteine to pyruvate, ammonia, and hydrogen sulfide, indicating that the protein is L-cysteine desulfhydrase. The enzyme required pyridoxal 5'-phosphate as a cofactor, and it was highly active at pH 7.0 and completely inhibited by ZnCl(2). The K(m) and V(max) of the enzyme were 0.7 mm and 4.2 micromol/min/mg, respectively. Replacement of Tyr-59, Tyr-118, Asp-198, and Lys-233 with any of the amino acids resulted in the complete disappearance of Lcs activity, implying that these amino acids are essential for enzyme activity. In addition, hydrogen sulfide produced by this enzyme lysed sheep red blood cells and modified hemoglobin. CONCLUSION: These results show the enzymatic properties of L-cysteine desulfhydrase from P. intermedia ATCC25611 and also suggest that the Lcs enzyme, which produces hydrogen sulfide from L-cysteine, is closely associated with the pathogenesis of P. intermedia.


Assuntos
Cistationina gama-Liase/química , Cistationina gama-Liase/genética , Hemólise/genética , Prevotella intermedia/enzimologia , Substituição de Aminoácidos , Clonagem Molecular , Cistationina gama-Liase/metabolismo , Hemólise/fisiologia , Sulfeto de Hidrogênio/metabolismo , Mutagênese Sítio-Dirigida , Proteínas Recombinantes
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