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1.
Int J Oral Maxillofac Surg ; 51(6): 713-723, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34483028

RESUMO

Melatonin receptors can inhibit breast and prostate cancers; however, little is known regarding their effects on oral squamous cell carcinoma. In this study, we collected specimens from 81 patients with oral squamous cell carcinoma and analysed clinicopathological data retrospectively. In addition, the expression of the melatonin receptor was analysed immunohistochemically. Survival rates were calculated using the Kaplan-Meier method and log-rank test. Multivariate analysis was performed based on the Cox proportional-hazards model. Further, an in vitro study was performed using YD15 cells. The cells were transfected with siRNA targeting melatonin receptor 1A and 1B for evaluating the malignancy of melatonin receptors by western blotting, trypan blue-exclusion, colony-forming, wound-healing, and invasion assays. Survival decreased as melatonin receptor expression and clinical and pathological tumour-node-metastasis stages increased. A Cox proportional-hazard model showed that melatonin receptor 1A may serve as a significant predictor of the survival rate of patients with oral squamous cell carcinoma [hazard ratio = 1.423, 95% confidence interval (CI) = 1.019-1.988, p = 0.038]. Melatonin receptor 1A and 1B knockdown significantly suppressed proliferation, migration ability, and invasion ability of YD15 cells in vitro. Our findings reveal that inhibiting melatonin receptor expression may suppress oral squamous cell carcinoma development.


Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Melatonina , Neoplasias Bucais , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/terapia , Humanos , Estimativa de Kaplan-Meier , Metástase Linfática , Masculino , Neoplasias Bucais/genética , Neoplasias Bucais/terapia , Prognóstico , Modelos de Riscos Proporcionais , Receptores de Melatonina , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço
2.
BJOG ; 127(1): 79-86, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31483927

RESUMO

OBJECTIVE: The present study aimed to analyse the Korean National Health Insurance Service (NHIS) cohort data to examine the safety of acupuncture therapy during pregnancy. DESIGN: Retrospective cohort. SETTING: Korea. POPULATION OR SAMPLE: Women with confirmed pregnancy between 2003 and 2012 from the 2002-13 NHIS sample cohort (n = 20 799). METHODS: Women with confirmed pregnancy were identified and divided into acupuncture or control group for comparison of their outcomes. Differences in other factors such as age, and rate of high-risk pregnancy and multiple pregnancy were examined. In the acupuncture group, the most frequent acupuncture diagnosis codes and the timing of treatment were also investigated. MAIN OUTCOME MEASURES: Incidence of full-term delivery, preterm delivery and stillbirth by pregnancy duration and among the high-risk and multiple pregnancy groups. RESULTS: Of 20 799 pregnant women analysed, 1030 (4.95%) and 19 749 were in the acupuncture and control groups, respectively. Both overall (odds ratio [OR] 1.23; 95% CI 0.98-1.54), and in the stratified analysis of high-risk pregnancies (OR 1.09; 95% CI 0.73-1.64), there was no significant difference between acupuncture and control groups in preterm deliveries. No stillbirths occurred in the acupuncture group and 0.035% of pregnancies resulted in stillbirths in the control group. CONCLUSION: No significant difference in delivery outcomes (preterm delivery and stillbirth) was observed between confirmed pregnancies in the acupuncture and control groups. Therefore, in pregnancy, acupuncture therapy may be a safe therapeutic modality for relieving discomfort without an adverse delivery outcome. TWEETABLE ABSTRACT: In pregnancy, acupuncture therapy may be a safe therapeutic modality for relieving discomfort without an adverse outcome.


Assuntos
Terapia por Acupuntura/efeitos adversos , Complicações na Gravidez/etiologia , Aborto Espontâneo/epidemiologia , Aborto Espontâneo/etiologia , Adolescente , Adulto , Distribuição por Idade , Criança , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Segurança do Paciente , Gravidez , Complicações na Gravidez/epidemiologia , Nascimento Prematuro/epidemiologia , Nascimento Prematuro/etiologia , República da Coreia/epidemiologia , Estudos Retrospectivos , Natimorto/epidemiologia , Adulto Jovem
3.
Rev Sci Instrum ; 84(7): 075104, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23902103

RESUMO

Femoroacetabular impingement stems from an abnormal shape of the acetabulum and proximal femur. It is treated by resection of damaged soft tissue and by the shaping of bone to resemble normal features. The arthroscopic treatment of femoroacetabular impingement has many advantages, including minimal incisions, rapid recovery, and less pain. However, in some cases, revision is needed owing to the insufficient resection of damaged bone from a misreading of the surgical site. The limited view of arthroscopy is the major reason for the complications. In this research, a navigation method for the arthroscopic treatment of femoroacetabular impingement is developed. The proposed navigation system consists of femur attachable measurement device and user interface. The bone mounted measurement devices measure points on head-neck junction for registration and position of surgical instrument. User interface shows the three-dimensional model of patient's femur and surgical instrument position that is tracked by measurement device. Surgeon can know the three-dimensional anatomical structure of hip joint and surgical instrument position on surgical site using navigation system. Surface registration was used to obtain relation between patient's coordinate at the surgical site and coordinate of three-dimensional model of femur. In this research, we evaluated the proposed navigation system using plastic model bone. It is expected that the surgical tool tracking position accuracy will be less than 1 mm.


Assuntos
Artroscopia/instrumentação , Impacto Femoroacetabular/cirurgia , Fêmur/cirurgia , Algoritmos , Desenho de Equipamento
4.
Int J Oral Maxillofac Surg ; 42(6): 790-5, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23294855

RESUMO

This study employed the cone-beam computed tomography (CBCT) superimposition method to evaluate postoperative midfacial soft-tissue changes in cases of skeletal Class III malocclusion after double-jaw surgery with setback and vertical reduction Le Fort I osteotomy. A retrospective study was carried out on 15 patients who had undergone maxillary setback Le Fort I osteotomy and mandibular setback sagittal split ramus osteotomy with alar cinch suturing and V-Y soft-tissue closure. Three dimensional CBCT volume scans were recorded preoperatively (T0) and 6 months postoperatively (T1) to measure soft-tissue changes of the upper lip and midface. Post-surgery, soft-tissue landmarks in the cheek and paranasal areas had moved forward; the soft-tissue thickness at the A-point had markedly increased (P<0.05); there was no significant change in the subnasale, and the midline of the soft-tissue of the upper-lip area had moved backward. The extent of the mean soft-tissue change at the labrale superius was greater than that at the other soft-tissue landmarks of the upper lip. The results suggest that maxillary setback movement of the maxilla by alar cinch suturing has a beneficial effect on paranasal soft-tissue and lip contours for patients with protrusive lip and acute nasolabial angle.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Face/anatomia & histologia , Má Oclusão Classe III de Angle/diagnóstico por imagem , Má Oclusão Classe III de Angle/cirurgia , Mandíbula/cirurgia , Maxila/cirurgia , Osteotomia de Le Fort , Adulto , Cefalometria , Feminino , Humanos , Masculino , Sulco Nasogeniano/anatomia & histologia , Osteotomia Sagital do Ramo Mandibular , Estudos Retrospectivos , Técnica de Subtração , Técnicas de Sutura , Resultado do Tratamento , Adulto Jovem
5.
Int J Oral Maxillofac Surg ; 41(1): 87-93, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22024138

RESUMO

The purpose of this study was to evaluate the volumetric change of the upper airway space in 36 Class III patients who had undergone bimaxillary surgery or isolated mandibular setback, and, further, to analyse the relation between post-surgical stability and airway change using cone-beam computed tomography (CBCT). A three-dimensional (3D) CBCT examination was performed at three stages: T0 (before surgery), T1 (an average of 4.6 months after surgery), and T2 (an average of 1.4 years after surgery). The results showed that the volumes of the oropharyngeal and hypopharyngeal airways decreased significantly 4.6 months post-surgery in the mandibular setback group (p<0.05), and these diminished airways had not recovered 1.4 years post-surgery. In the bimaxillary surgery group, the volume of the oropharyngeal airway also decreased. A Spearman correlation analysis showed that the anteroposterior length of the hypopharyngeal area had a correlation with post-surgical stability in the isolated mandibular surgery group, and that the cross-sectional area of the nasopharynx was correlated with maxillary relapse only in the bimaxillary surgery group (p<0.05).


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Má Oclusão Classe III de Angle/cirurgia , Mandíbula/cirurgia , Maxila/cirurgia , Procedimentos Cirúrgicos Ortognáticos/métodos , Faringe/diagnóstico por imagem , Adulto , Anatomia Transversal , Placas Ósseas , Parafusos Ósseos , Cefalometria/métodos , Feminino , Seguimentos , Humanos , Hipofaringe/diagnóstico por imagem , Hipofaringe/patologia , Imageamento Tridimensional/métodos , Masculino , Mandíbula/patologia , Maxila/patologia , Nasofaringe/diagnóstico por imagem , Nasofaringe/patologia , Orofaringe/diagnóstico por imagem , Orofaringe/patologia , Osteotomia de Le Fort/instrumentação , Osteotomia de Le Fort/métodos , Osteotomia Sagital do Ramo Mandibular/instrumentação , Osteotomia Sagital do Ramo Mandibular/métodos , Faringe/patologia , Recidiva , Adulto Jovem
6.
Environ Toxicol ; 22(5): 532-8, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17696134

RESUMO

Marine copepods have recently been recognized as important organisms in ecotoxicity testing for regulatory purposes. The harpacticoid copepod Tigriopus japonicus has a wide geographical distribution along the coast in the Western Pacific including Japan, South Korea, Taiwan, and Hong Kong. This study evaluated the acute toxicity sensitivity profile of Tigriopus japonicus against 12 common toxic substances including six endocrine disrupting chemicals (EDCs), three biocides and three trace metals. Through standard acute toxicity test procedures, toxicity endpoints LC(50), LC(10), and no observed effect concentration (NOEC) of each chemical were obtained. Although T. japonicus depicted different sensitivities towards different chemicals, a dose-response relationship was consistent in all cases. T. japonicus was particularly sensitive to most of the EDCs, but relatively less sensitive to molinate (a thiocarbate herbicide). Across all tested chemicals, tributyltin (TBT) was the most toxic to the copepod with the LC(50), LC(10), and NOEC of 0.05, 0.03, and 0.02 mg/L, respectively. A comparison made with available data on acute toxicities of these chemicals to other marine copepod species revealed that T. japonicus is generally more sensitive to EDCs and in particular to TBT. We, therefore, strongly advocate that T. japonicus shall be adopted as a benchmark marine species for routine ecotoxicity testing and ecotoxicological studies in Western Pacific coasts.


Assuntos
Copépodes/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Xenobióticos/toxicidade , Animais , Dose Letal Mediana , Nível de Efeito Adverso não Observado , Oceano Pacífico , Praguicidas/toxicidade , Fenóis/toxicidade , Bifenilos Policlorados/toxicidade , Medição de Risco/métodos , Testes de Toxicidade/métodos , Compostos de Trialquitina/toxicidade
7.
J Bone Joint Surg Br ; 88(10): 1390-2, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17012434

RESUMO

In a 41-year-old man, right-sided infraspinatus muscle weakness was associated with compression of the suprascapular nerve caused by a spinoglenoid ganglion cyst. The lesion was confirmed using electromyography and MRI. In addition, arthroscopy showed an incomplete discoid labrum. The free inner edge of the labrum was removed as in a meniscectomy of a discoid meniscus in the knee joint. Arthroscopic decompression of the cyst was performed through a juxtaglenoid capsulotomy which was left open. Neurological function recovered completely.


Assuntos
Cistos Glanglionares/patologia , Síndromes de Compressão Nervosa/patologia , Escápula/anormalidades , Articulação do Ombro/patologia , Adulto , Artroscopia/métodos , Cistos Glanglionares/complicações , Cistos Glanglionares/cirurgia , Humanos , Masculino , Síndromes de Compressão Nervosa/complicações , Síndromes de Compressão Nervosa/cirurgia , Resultado do Tratamento
8.
Oncogene ; 25(2): 298-303, 2006 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-16170356

RESUMO

BRCA1-dependent ubiquitination activity regulates centrosome number in several tissue culture cell lines derived from breast cells. In these experiments, we asked how BRCA1 inhibits centrosome amplification. In general, supernumerary centrosomes can accumulate by three mechanisms: (1) failed cytokinesis and the accumulation of centrosomes by duplication in a repeated S-phase of the cell cycle, (2) disruption of the licensing of centrosome doubling such that they duplicate at inappropriate times in the cell cycle, or (3) fragmentation of the centrosomes. In this study, we found that inhibition of BRCA1 caused premature separation of centrioles and reduplication. By blocking cells in early S-phase before centrosome amplification secondary to BRCA1 inhibition could occur and then releasing, we found that inhibition of BRCA1 caused centrosome amplification between late S-phase and G2/M before the cell divided. These results suggest that normal BRCA1 function is critical in these cell lines to prevent centriole separation and centrosome reduplication before mitosis.


Assuntos
Proteína BRCA1/antagonistas & inibidores , Neoplasias da Mama/metabolismo , Divisão Celular , Centrossomo/metabolismo , Fase G2 , Glândulas Mamárias Humanas/metabolismo , Fase S , Adenocarcinoma/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Células Cultivadas , Centríolos/metabolismo , Centrossomo/efeitos dos fármacos , Feminino , Humanos , Hidroxiureia/farmacologia , Mitose , RNA Interferente Pequeno/farmacologia
9.
Cell Death Differ ; 12 Suppl 1: 962-70, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15832179

RESUMO

The destruction of CD4(+) T cells and eventual induction of immunodeficiency is a hallmark of the human immunodeficiency virus type 1 infection (HIV-1). However, the mechanism of this destruction remains unresolved. Several auxiliary proteins have been proposed to play a role in this aspect of HIV pathogenesis including a 14 kDa protein named viral protein R (Vpr). Vpr has been implicated in the regulation of various cellular functions including apoptosis, cell cycle arrest, differentiation, and immune suppression. However, the mechanism(s) involved in Vpr-mediated apoptosis remains unresolved, and several proposed mechanisms for these effects are under investigation. In this review, we discuss the possibility that some of these proposed pathways might converge to modulate Vpr's behavior. Further, we also discuss caveats and future directions for investigation of the interesting biology of this HIV accessory gene.


Assuntos
Apoptose , Linfócitos T CD4-Positivos/virologia , Produtos do Gene vpr/fisiologia , HIV-1/fisiologia , Proteínas Adaptadoras de Transdução de Sinal , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Complexo do Signalossomo COP9 , Proteínas de Transporte/fisiologia , Fatores de Iniciação em Eucariotos/fisiologia , Produtos do Gene vpr/antagonistas & inibidores , Produtos do Gene vpr/farmacologia , Proteínas de Choque Térmico HSP70/farmacologia , Humanos , Membranas Intracelulares/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Complexos Multiproteicos/fisiologia , Peptídeo Hidrolases/fisiologia , Receptores de Glucocorticoides/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Produtos do Gene vpr do Vírus da Imunodeficiência Humana
10.
J Med Primatol ; 31(4-5): 179-85, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12390540

RESUMO

We compared the immunogenicity of plasmid vaccines containing multiple human immunodeficiency virus (HIV) antigens and found that covaccination with plasmids expressing HIV-1 14 kDa vpr gene product profoundly reduces antigen-specific CD8-mediated cytotoxic T-cell activity (CTL). Interestingly, Th1 type responses against codelivered antigens (pGag-Pol, pNef, etc.) encoded by the plasmid vaccines were suppressed. This suggested that vpr might compromise CD8 T-cell immunity in vivo during infection. A pilot primate vaccine study was designed to test the hypothesis to compare the following groups: unvaccinated controls, animals vaccinated without simean immunodeficiency virus (SIV)-Nef antigen plasmid, and animals covaccinated with the identical plasmid antigen and a plasmid construct encoding SIV Vpr/Vpx. Animals were subsequently challenged intrarectally with pathogenic SIVmac251 after the final vaccination of a multiple immunization protocol. Control animals were all infected and exhibited high viral loads and rapid CD4+ T-cell loss. In contrast, the Nef plasmid-vaccinated animals were also infected but exhibited preservation of CD4+ T-cells and a multilog reduction in viral load compared with controls. Animals covaccinated multiple times with the Nef vaccine and pVpr/Vpx plasmid suffered rapid and profound loss of CD4+ T-cells. These results have important implications for the design of multicomponent and particle vaccines for HIV-1 as well as for our understanding of HIV/SIV pathogenesis in vivo.


Assuntos
Linfócitos T CD4-Positivos/citologia , Produtos do Gene nef/imunologia , Produtos do Gene vpr/imunologia , Macaca mulatta/imunologia , Macaca mulatta/virologia , Vacinas contra a SAIDS/genética , Vacinas contra a SAIDS/imunologia , Vírus da Imunodeficiência Símia/imunologia , Carga Viral , Animais , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/imunologia , Modelos Animais de Doenças , Feminino , Produtos do Gene nef/genética , Produtos do Gene vpr/genética , Modelos Logísticos , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Plasmídeos/genética , RNA Viral/sangue , RNA Viral/genética , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/fisiologia , Fatores de Tempo , Vacinas de DNA/genética , Vacinas de DNA/imunologia
11.
J Biol Chem ; 276(44): 40873-9, 2001 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-11527965

RESUMO

To adapt to anaerobic conditions, Escherichia coli operates the Arc two-component signal transduction system, consisting of a sensor kinase, ArcB, and a response regulator, ArcA. ArcA is converted to the active form, phosphorylated ArcA (ArcA-P), by ArcB-mediated phosphorylation. The active ArcA-P binds to the promoter regions of target genes, thereby regulating their transcriptional activities. The phosphoryl group of ArcA-P is unstable with a half-life of 30 min. However, we were able to inhibit the dephosphorylation for more than 12 h by the addition of EDTA; this allowed us to characterize ArcA-P. Gel-filtration and glycerol sedimentation experiments demonstrated that ArcA exists as a homo-dimer. ArcA phosphorylated by either ArcB or carbamyl phosphate multimerizes to form a tetramer of dimers; this multimer binds to the ArcA DNA binding site. Isoelectric focusing gel electrophoresis and nitrocellulose-filter binding analyses indicated that the ArcA multimer is composed of both ArcA-P and ArcA in a ratio, 1:1. The ArcA(D54E) mutant protein was unable to be phosphorylated by ArcB. This defect resulted in the inability of ArcA(D54E) to form a multimer or to bind to the ArcA DNA binding site. These results indicate that phosphorylation of ArcA induces multimerization prior to DNA binding, and the multimerization is a prerequisite for binding. Our results suggest a novel model that phosphorylation of ArcA by ArcB regulates multimerization of ArcA, which in turn functions as a response regulator.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas Repressoras , Transdução de Sinais , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/isolamento & purificação , Sequência de Bases , Biopolímeros , Primers do DNA , Proteínas de Escherichia coli , Mutagênese , Fosforilação
12.
J Biol Chem ; 276(37): 34600-6, 2001 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-11457824

RESUMO

The binding of SeqA protein to hemimethylated GATC sequences is important in the negative modulation of chromosomal initiation at oriC, and in the formation of SeqA foci necessary for Escherichia coli chromosome segregation. Using gel-filtration chromotography and glycerol gradient sedimentation, we demonstrate that SeqA exists as a homotetramer. SeqA tetramers are able to aggregate or multimerize in a reversible, concentration-dependent manner. Using a bacterial two-hybrid system, we demonstrate that the N-terminal region of SeqA, especifically the 9th amino acid residue, glutamic acid, is required for functional SeqA-SeqA interaction. Although the SeqA(E9K) mutant protein, containing lysine rather than glutamic acid at the 9th amino acid residue, exists as a tetramer, the mutant protein binds to hemimethylated DNA with altered binding patterns as compared with wild-type SeqA. Aggregates of SeqA(E9K) are defective in hemimethylated DNA binding. Here we demonstrate that proper interaction between SeqA tetramers is required for both hemimethylated DNA binding and formation of active aggregates. SeqA tetramers and aggregates might be involved in the formation of SeqA foci required for the segregation of chromosomal DNA as well as the regulation of chromosomal initiation.


Assuntos
Fatores de Transcrição/química , Proteínas da Membrana Bacteriana Externa , DNA/metabolismo , Metilação de DNA , Proteínas de Ligação a DNA , Proteínas de Escherichia coli , Fatores de Transcrição/fisiologia , Técnicas do Sistema de Duplo-Híbrido
13.
Mol Gen Genet ; 264(6): 931-5, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11254141

RESUMO

The SeqA protein acts as a regulator of chromosomal replication initiation in Escherichia coli by sequestering hemi-methylated oriC, effectively blocking methylation and therefore preventing rapid re-initiation. The level of SeqA protein is maximal at mid-log phase and decreases when cells enter late-log phase. In hup mutants that lack the HU protein, the maximal seqA expression is also seen at mid-log phase, but seqA expression, as well as SeqA levels and activity, is increased by up to four fold relative to that in the wild type. These results suggest that the HU protein functions as a negative modulator of seqA expression.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Proteínas da Membrana Bacteriana Externa , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Proteínas de Escherichia coli , Genótipo , Cinética , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas , Fatores de Transcrição/metabolismo
14.
J Biol Chem ; 276(13): 9917-23, 2001 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-11133990

RESUMO

Under anaerobic growth conditions, Escherichia coli operates a two-component signal transduction system, termed Arc, that consists of ArcB protein, a transmembrane sensor kinase and ArcA protein, the cognate response regulator. In response to low oxygen levels, autophosphorylated ArcB phosphorylates ArcA, and the resulting phosphorylated ArcA (ArcA-P) functions as a transcriptional regulator of the genes necessary to maintain anaerobic growth. Under anaerobic conditions, cells maintain a slow growth rate, suggesting that the initiation of chromosomal replication is regulated to reduce the initiation frequency. DNase I footprinting experiments revealed that ArcA-P binds to the left region of the chromosomal origin, oriC. ArcA-P did not affect the in vitro replication of plasmid DNA containing the ColE1 origin nor the in vitro replication of viral DNAs; however, ArcA-P specifically inhibited in vitro E. coli chromosomal replication. This inhibition was caused by the prevention of open complex formation, a necessary step in the initiation of chromosomal replication. Our in vitro results suggest that the Arc two-component system participates in regulating chromosomal initiation under anaerobic growth conditions.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Cromossomos/metabolismo , Proteínas de Escherichia coli , Escherichia coli/metabolismo , Proteínas de Membrana/fisiologia , Proteínas Quinases/fisiologia , Proteínas Repressoras , Transdução de Sinais , Proteínas de Bactérias/metabolismo , Divisão Celular , DNA/metabolismo , Replicação do DNA , Proteínas de Ligação a DNA/metabolismo , Desoxirribonuclease I/metabolismo , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Escherichia coli/genética , Complexo de Reconhecimento de Origem , Oxigênio/metabolismo , Fosforilação , Plasmídeos/metabolismo , Ligação Proteica , Transcrição Gênica , Proteínas Virais/metabolismo
15.
Mol Cells ; 10(5): 519-24, 2000 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-11101142

RESUMO

TLHS1 is a class I low molecular weight heat-shock protein (LMW HSP) of tobacco (Nicotiana tabacum). For a functional study of TLHS1, a recombinant DNA coding for TLHS1 with a hexahistidine tag at the amino-terminus was constructed and expressed in Escherichia coli. An expressed fusion protein, H6TLHS1, was purified using a Ni2+ affinity column and a Sephacryl S400 HR column. A polyclonal antibody against H6TLHS1 was produced to follow the fate of H6TLHS1 in E. coli. The fusion protein in E. coli maintained its solubility at a temperature of up to 90 degrees C and most of the proteins in the E. coli cell lysate with H6TLHS1 were prevented from thermally induced aggregation at up to 90 degrees C. We compared the viability of E. coli cells expressing H6TLHS1 to the E. coli cells without H6TLHS1 at a temperature of 50 degrees C. After 8 h of high temperature treatment, E. coli cells with H6TLHS1 survived about three thousand times more than the bacterial cells without H6TLHS1. These results showed that a plant class I LMW HSP, TLHS1, can protect proteins of E. coli from heat denaturation, which could lead to a higher survival rate of the bacterial cells at high temperature.


Assuntos
Escherichia coli/fisiologia , Proteínas de Choque Térmico/fisiologia , Nicotiana/genética , Plantas Tóxicas , Clonagem Molecular , Escherichia coli/citologia , Escherichia coli/genética , Proteínas de Choque Térmico/genética , Temperatura Alta , Peso Molecular , Proteínas Recombinantes de Fusão/metabolismo , Nicotiana/fisiologia
16.
Cancer Lett ; 148(1): 105-10, 2000 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-10680599

RESUMO

p27Kip1, a cyclin-dependent kinase (CDK) inhibitor, plays a critical role in cell cycle regulation. Expression of p27Kip1 is shown to increase during apoptosis in mammalian cells. Here, to directly address the role of p27Kip1 in apoptosis, p27Kip1 is overexpressed in human SK-Hep1 hepatoma cells. This leads to apoptotic cell death and this reduces protein, but not mRNA, levels of the retinoblastoma (Rb). Consistently, accumulation of Rb protein blocks p27Kip1-mediated apoptosis. These studies demonstrate an involvement of Rb in the apoptotic cell death which is induced by overexpression of p27Kip1.


Assuntos
Apoptose , Proteínas de Ciclo Celular , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína do Retinoblastoma/metabolismo , Proteínas Supressoras de Tumor , Western Blotting , Inibidor de Quinase Dependente de Ciclina p27 , Quinases Ciclina-Dependentes/antagonistas & inibidores , DNA/análise , DNA/genética , Fragmentação do DNA , Regulação para Baixo , Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Proteínas Associadas aos Microtúbulos/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína do Retinoblastoma/genética , Transfecção , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
17.
J Biomed Mater Res ; 53(1): 100-10, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10634959

RESUMO

The size and morphology of particulate wear debris retrieved from tissues around 18 failed total knee replacements (TKR) were characterized. Interfacial membranes from nine cemented and nine uncemented TKR were harvested from below the tibial components during revision surgery. Wear debris were extracted using papain and potassium hydroxide digestion. Ultrahigh molecular weight polyethylene (UHMWPE) particles from around cemented or uncemented TKR were similar in size and morphology. The mean size was 1.7 +/- 0. 7 microm with a range of 0.1-18 microm. Thirty-six percent of the particles were less than 1 microm and 90% were less than 3 microm. Morphologically the particles were predominantly spherical with occasional fibrillar attachments and flakes. Particles from TKR were greater than threefold larger than previously characterized particles from total hip replacements, which were 0.5 microm in mean size. Differences in joint conformity and wear patterns between the hip and knee articulations may explain the disparity in size of the wear debris. Since particle size represents an important variable influencing the magnitude of the biological response, it is possible that in vivo the larger TKR debris results in a diminished mediator release, which in turn may account for the lower incidence of osteolysis and aseptic loosening in some designs of TKR.


Assuntos
Materiais Biocompatíveis , Prótese do Joelho , Polietileno , Falha de Prótese , Idoso , Materiais Biocompatíveis/química , Feminino , Humanos , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Peso Molecular , Tamanho da Partícula , Polietileno/química , Fatores de Tempo
18.
Mol Gen Genet ; 262(3): 448-52, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10589831

RESUMO

The IciA protein from Escherichia coli has been shown specifically to inhibit the in vitro initiation of chromosomal DNA replication. However, the in vivo role of IciA has not yet been established. In order to investigate the in vivo function of this protein, expression of the iciA gene was studied by monitoring the beta-galactosidase activity specified by an iciA promoter-lacZ fusion inserted into the chromosome. Among the conditions tested (carbon starvation, the stringent response, phosphate starvation, and the SOS response), only phosphate depletion increased iciA expression. Supplementation of phosphate-depleted cultures with inorganic phosphate reduced the beta-galactosidase activity to basal levels. Enhanced expression of iciA-lacZ was dependent upon the PhoB protein. PhoB is known to be a transcriptional activator of the Pho regulon, expression of which is activated during phosphate starvation. It was also found that the iciA promoter contains a PhoB protein-binding sequence, termed the Pho box, which is necessary for the activation of genes of the Pho regulon. These results suggest that the iciA gene is a member of the Pho regulon.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Escherichia coli , Escherichia coli/genética , Fosfatos/deficiência , Ativação Transcricional , Proteínas de Bactérias/biossíntese , Proteínas de Ligação a DNA/biossíntese , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Regulon
19.
Zhonghua Yi Xue Za Zhi (Taipei) ; 62(9): 598-604, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10502850

RESUMO

BACKGROUND: High-resolution peripheral vascular sonography has the capability to determine vessel compliance. A number of factors affect compliance in humans, including age, hypertension and atherosclerosis. However, compliance in patients with coronary artery disease (CAD) combined with carotid artery lesions has not been well studied. The objectives of this study were: 1) to determine whether carotid artery compliance is reduced in patients with CAD and carotid artery lesions, and 2) to determine whether decreased arterial compliance is related to an abnormality in vascular wall structure. METHODS: The study participants included 12 patients with CAD and carotid artery disease (group III), 13 patients with CAD only (group II) and 13 age-matched normal subjects who served as controls (group I). High-resolution peripheral vascular ultrasonography was performed to directly visualize the common carotid artery and to measure its diameter and wall thickness. Carotid artery elastic properties were determined relative to arterial diameter and pressure generated within the heart. RESULTS: Carotid artery walls were thicker in Group II and III patients than in normal subjects (1.49 +/- 0.03 mm, 1.98 +/- 0.04 mm, vs 1.22 +/- 0.03 mm, p < 0.05 and p < 0.01). There were significant differences in wall thickness between subgroups of CAD patients (p < 0.01). Carotid distensibility was lower (21.8 +/- 1.2 x 10(-6).N-1.m2, 14.8 +/- 1.7 x 10(-6).N-1.m2, vs 25.6 +/- 1.5 x 10(-6).N-1.m2; p < 0.05 and p < 0.01) and Young's modulus of elasticity was higher (3.12 +/- 0.43 x 10(5).Nm-2, 4.18 +/- 0.30 x 10(5).Nm-2, vs 2.34 +/- 0.23 x 10(5).Nm-2; p < 0.05 and p < 0.01) in group II and III patients than in normal subjects. These two indices of carotid artery compliance also differed between subgroups of CAD (p < 0.01). Increased wall thickness may occur secondary to changes in the architectural structure of the vessel wall, and these atherosclerotic changes lead to decreased compliance of arteries. CONCLUSION: The mechanical properties of the carotid arteries provide reliable information regarding changes caused by atherosclerosis.


Assuntos
Arteriosclerose/fisiopatologia , Artérias Carótidas/fisiopatologia , Doenças das Artérias Carótidas/fisiopatologia , Pressão Sanguínea , Artérias Carótidas/diagnóstico por imagem , Complacência (Medida de Distensibilidade) , Humanos , Pessoa de Meia-Idade , Ultrassonografia
20.
J Biol Chem ; 274(17): 11463-8, 1999 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-10206949

RESUMO

Preferential binding of SeqA protein to hemimethylated oriC, the origin of Escherichia coli chromosomal replication, delays methylation by Dam methylase. Because the SeqA-oriC interaction appears to be essential in timing of chromosomal replication initiation, the biochemical functions of SeqA protein and Dam methylase at the 13-mer L, M, and R region containing 4 GATC sequences at the left end of oriC were examined. We found that SeqA protein preferentially bound hemimethylated 13-mers but not fully nor unmethylated 13-mers. Regardless of strand methylation, the binding of SeqA protein to the hemimethylated GATC sequence of 13-mer L was followed by additional binding to other hemimethylated GATC sequences of 13-mer M and R. On the other hand, Dam methylase did not discriminate binding of 13-mers in different methylation patterns and was not specific to GATC sequences. The binding specificity and higher affinity of SeqA protein over Dam methylase to the hemimethylated 13-mers along with the reported cellular abundance of this protein explains the dominant action of SeqA protein over Dam methylase to the newly replicated oriC for the sequestration of chromosomal replication. Furthermore, SeqA protein bound to hemimethylated 13-mers was not dissociated by Dam methylase, and most SeqA protein spontaneously dissociated 10 min after binding. Also, SeqA protein delayed the in vitro methylation of hemimethylated 13-mers by Dam methylase. These in vitro results suggest that the intrinsic binding instability of SeqA protein results in release of sequestrated hemimethylated oriC.


Assuntos
Proteínas de Bactérias/metabolismo , Cromossomos Bacterianos , Escherichia coli/genética , Origem de Replicação , DNA Metiltransferases Sítio Específica (Adenina-Específica)/metabolismo , Fatores de Transcrição , Proteínas da Membrana Bacteriana Externa , Sequência de Bases , Metilação de DNA , DNA Bacteriano , Proteínas de Ligação a DNA , Proteínas de Escherichia coli , Dados de Sequência Molecular , Ligação Proteica
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