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1.
J Stomatol Oral Maxillofac Surg ; 122(3): 267-272, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32622002

RESUMO

Cryosurgery is a recognized method for the treatment of mucoceles in the oral cavity. In this study, cryosurgery was used for mucoceles at the lip or buccal mucosa, and the effect and the indication were evaluated clinically. The subjects were patients with a clinical diagnosis of mucocele on the lip or buccal mucosa and who chose cryosurgery after procedures for both surgical excision and cryosurgery for the lesion were explained. Cryosurgery was performed with a freezing device using liquid nitrogen without local anesthesia. Twenty-four patients chose cryosurgery, including seven preschool children. There were no serious adverse events during and after cryosurgery. Healing progress after cryosurgery was not affected by patient age, lesion size, or how long the patients had the lesion. Two cases later underwent surgical excision because cryosurgery was not successful. Twenty-three patients chose surgical excision, one case had a recurrence. The number of younger patients who chose cryosurgery was significantly higher than that who chose surgical excision. This study suggests that cryosurgery is effective for mucoceles of the lip or buccal mucosa and is a simple and safe treatment method, especially for preschool children.


Assuntos
Criocirurgia , Doenças da Boca , Mucocele , Pré-Escolar , Criocirurgia/efeitos adversos , Humanos , Doenças da Boca/cirurgia , Mucocele/diagnóstico , Mucocele/cirurgia , Recidiva Local de Neoplasia
2.
Int J Oral Maxillofac Surg ; 47(7): 896-899, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29625719

RESUMO

This study investigated the utility of endocytoscopy, a novel emerging endoscopic system, for in situ real-time histology of oral mucosal lesions. Endocytoscopy involves the use of a contact light microscopy system with 380-fold magnification. With the development of endoscopic instruments, it has become possible to observe the abnormal microvascular and capillary patterns of tumour cells. The resolution of the endoscopic image is improved in situ, and a more detailed diagnosis is possible. In this study, endocytoscopy along with other diagnostic modalities was used in nine patients. Normal mucous membranes and oral malignant lesions were observed. Endocytoscopy enabled the pathological diagnosis of oral malignancies in situ and the observation of both structural and cytological atypia. In the future, it is expected that pathological diagnoses will be made in situ by direct viewing of living cells. This technique has the potential to allow an 'optical biopsy'.


Assuntos
Endoscopia/instrumentação , Microscopia/instrumentação , Mucosa Bucal/diagnóstico por imagem , Neoplasias Bucais/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Biópsia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/patologia , Neoplasias Bucais/cirurgia
3.
Med Oral Patol Oral Cir Bucal ; 21(3): e341-8, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-27031062

RESUMO

BACKGROUND: 18F-fluoro-2-deoxy-D-glucose (18F-FDG) accumulations are commonly seen in the neck-related muscles of the surgical and non-surgical sides after surgery with neck dissection (ND) for oral cancers, which leads to radiologists having difficulty in diagnosing the lesions. To examine the alterations in 18F-FDG accumulation in neck-related muscles of patients after ND for oral cancer. MATERIAL AND METHODS: 18F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) in neck-related muscles were retrospectively analyzed after surgical dissection of cervical lymph nodes in oral cancers. RESULTS: According to the extent of ND of cervical lymph nodes, the rate of patients with 18F-FDG-PET-positive areas increased in the trapezius, sternocleidomastoid, and posterior neck muscles of the surgical and/or non-surgical sides. In addition, SUVmax of 18F-FDG-PET-positive areas in the trapezius and sternocleidomastoid muscles were increased according to the extent of the ND. CONCLUSIONS: In evaluating 18F-FDG accumulations after ND for oral cancers, we should pay attention to the 18F-FDG distributions in neck-related muscles including the non-surgical side as false-positive findings.


Assuntos
Fluordesoxiglucose F18/farmacocinética , Neoplasias Bucais/diagnóstico por imagem , Esvaziamento Cervical , Compostos Radiofarmacêuticos/farmacocinética , Humanos , Metástase Linfática , Neoplasias Bucais/patologia , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios X
4.
Int J Oral Maxillofac Surg ; 45(2): 194-9, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26599693

RESUMO

A modified technique of horseshoe osteotomy combined with Le Fort I osteotomy for superior and posterior repositioning of the maxilla is presented. Eight patients with maxillary excess associated with retrogenia or microgenia were treated with this technique in combination with genioplasty. The maxillary segment was repositioned a maximum of 5.0mm posteriorly and 7.0mm superiorly at point A. The mandible autorotated anterosuperiorly to achieve sound occlusion. Point B moved 2.0-10.0mm anteriorly and 5.0-10.0mm superiorly. The pogonion moved 7.0-17.0mm anteriorly in combination with genioplasty. All patients obtained sound occlusion and a good profile after the operation. Almost no skeletal relapse was observed during 1 year of postoperative follow-up. Patients with long faces with maxillary excess and retrogenia often have small, unstable condyles. In these cases, because surgical intervention to the ramus can result in postoperative progressive condylar resorption, maxillary single-jaw surgery with a horseshoe osteotomy, thereby avoiding ramus intervention, is a less invasive option.


Assuntos
Maxila/anormalidades , Maxila/cirurgia , Procedimentos Cirúrgicos Ortognáticos , Osteotomia/métodos , Adulto , Cefalometria , Feminino , Mentoplastia , Humanos , Japão , Osteotomia de Le Fort , Resultado do Tratamento
5.
Dentomaxillofac Radiol ; 42(7): 20130014, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23610089

RESUMO

OBJECTIVES: To elucidate the points that require attention when interpreting fluorine-18-labelled fluoro-2-deoxy-d-glucose ((18)F-FDG)/positron emission tomography (PET) images by demonstration of (18)F-FDG accumulation in various areas of the oral cavity other than primary lesions in patients with oral cancers. METHODS: (18)F-FDG accumulations with a maximal standardized uptake value of over 2.5 in various areas of the oral cavity other than primary lesions were identified in 82 patients with oral cancers. RESULTS: (18)F-FDG/PET-positive areas, excluding primary tumours, included the front intrinsic muscles of the tongue (89.0%), upper and lower marginal parts of the orbicularis oris muscle (64.6%), sublingual glands, palatine tonsil, pharyngeal tonsil, and lingual tonsil. In addition, some areas in the jaws also showed accumulation. CONCLUSIONS: In patients with oral cancers, areas of (18)F-FDG accumulation in the oral cavity should be precisely identified and appropriately diagnosed, because accumulations can be seen in areas other than the primary tumour.


Assuntos
Fluordesoxiglucose F18 , Neoplasias Bucais/diagnóstico por imagem , Boca/diagnóstico por imagem , Imagem Multimodal/métodos , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/metabolismo , Músculos Faciais/diagnóstico por imagem , Músculos Faciais/metabolismo , Feminino , Fluordesoxiglucose F18/farmacocinética , Neoplasias Gengivais/diagnóstico por imagem , Neoplasias Gengivais/metabolismo , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética , Masculino , Mandíbula/diagnóstico por imagem , Mandíbula/metabolismo , Maxila/diagnóstico por imagem , Maxila/metabolismo , Pessoa de Meia-Idade , Boca/metabolismo , Neoplasias Bucais/metabolismo , Tonsila Palatina/diagnóstico por imagem , Tonsila Palatina/metabolismo , Compostos Radiofarmacêuticos/farmacocinética , Glândula Sublingual/diagnóstico por imagem , Glândula Sublingual/metabolismo , Tomografia Computadorizada por Raios X , Língua/diagnóstico por imagem , Língua/metabolismo , Neoplasias da Língua/diagnóstico por imagem , Neoplasias da Língua/metabolismo , Adulto Jovem
6.
Appl Opt ; 50(13): 1941-4, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21532677

RESUMO

Glass welding by ultrashort laser pulses allows joining without the need of an absorber or a preheating and postheating process. However, cracks generated during the welding process substantially impair the joining strength of the welding seams. In this paper a sample preparation method is described that prevents the formation of cracks. The measured joining strength of samples prepared by this method is substantially higher than previously reported values.

10.
Thromb Res ; 101(6): 493-500, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11323007

RESUMO

The pharmacokinetics of pamiteplase and recombinant tissue-type plasminogen activator (rt-PA) in rats, dogs, and monkeys were examined using a newly developed enzyme-linked immunosorbent assay (ELISA). Plasma concentrations after intravenous administration of pamiteplase to rats declined in a triphasic manner. Plasma concentrations after intravenous administration of pamiteplase to dogs or monkeys declined in a biphasic manner. The area under the plasma concentration-time curve from zero to infinity (AUC(0-->infinity)) in rats and dogs increased with increasing dose. The half-life and mean residence time of pamiteplase in rats, dogs, and monkeys were shown to be longer than those of rt-PA. Total clearance (CL(total)) of pamiteplase was only 7-16% that of rt-PAs, suggesting that concentrations of pamiteplase in plasma were higher and more continuous than those of rt-PA in these experimental animals. The data suggest that a bolus administration of pamiteplase shows the same thrombolytic activity as continuous infusion of rt-PA in experimentally induced thrombosis in rats and dogs. The pharmacokinetic parameters distribution volume at the steady state and CL(total) calculated by immunoreactive concentration after administration of pamiteplase to rats, dogs, and monkeys show high correlation with body weights (r(2)=.7728 and .9039).


Assuntos
Proteínas Recombinantes/farmacocinética , Ativador de Plasminogênio Tecidual/farmacocinética , Animais , Área Sob a Curva , Peso Corporal , Cães , Ensaio de Imunoadsorção Enzimática/normas , Meia-Vida , Haplorrinos , Injeções Intravenosas , Masculino , Taxa de Depuração Metabólica , Ratos , Ratos Endogâmicos F344 , Proteínas Recombinantes/sangue , Ativador de Plasminogênio Tecidual/sangue
11.
Xenobiotica ; 30(10): 993-1003, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11315107

RESUMO

1. An enzyme-linked immunosorbent assay (ELISA) and functional bioassay to determine immunoreactive and bioactive concentrations of pamiteplase, a novel thrombolytic agent, in human plasma were developed. The ELISA and functional bioassay showed satisfactory accuracy and precision within a concentration range of 0.5-25 ng.ml(-1) and of 0.127-16.2 ng.ml(-1) respectively. 2. The pharmacokinetics of pamiteplase in healthy human subjects were evaluated using the ELISA and functional bioassay. Irrespective of the method used, plasma concentrations declined bi-exponentially. Half-lives in the beta phase were 1.25 and 0.78 h, and AUCs were 507.9 and 286.4 ng.h.ml(-1) respectively. Total clearances of pamiteplase decreased to 19 and 31% of those of the wild-type tissue-type plasminogen activator. 3. The protein binding of pamiteplase in human plasma was investigated by gel filtration chromatography. Pamiteplase formed three high molecular weight complexes with alpha2-macroglobulin, C1-esterase inhibitor and alpha2-plasmin inhibitor in human plasma. This complex formation was relatively slow, and was thought to be irreversible and covalently bounded. Furthermore, this protein binding in humans resulted in the termination of biological action.


Assuntos
Proteínas Recombinantes/sangue , Proteínas Recombinantes/farmacocinética , Ativador de Plasminogênio Tecidual/sangue , Ativador de Plasminogênio Tecidual/farmacocinética , Adulto , Animais , Anticorpos Monoclonais , Área Sob a Curva , Bioensaio , Ensaio de Imunoadsorção Enzimática , Humanos , Radioisótopos do Iodo , Masculino , Taxa de Depuração Metabólica , Camundongos , Camundongos Endogâmicos BALB C , Coelhos
12.
Intern Med ; 38(10): 804-7, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10526944

RESUMO

A 59-year-old man was admitted to our hospital because of muscular pain, weakness, and anorexia. He had been treated with 600 mg/day of fosfestrol, a synthetic estrogen, for 10 years for prostatic carcinoma. Endocrinological studies demonstrated adrenocortical insufficiency due to inadequate ACTH secretion. After initiation of glucocorticoid replacement therapy, his symptoms subsided rapidly. To our knowledge, an association between estrogenic agents, including fosfestrol, and secondary adrenocortical insufficiency has not been previously reported. Physicians who treat patients with long-term and high-dose strong estrogenic agents should be cautious about the possible emergence of secondary adrenocortical insufficiency.


Assuntos
Insuficiência Adrenal/induzido quimicamente , Antineoplásicos/efeitos adversos , Dietilestilbestrol/análogos & derivados , Neoplasias da Próstata/tratamento farmacológico , Insuficiência Adrenal/metabolismo , Hormônio Adrenocorticotrópico/metabolismo , Antineoplásicos/uso terapêutico , Dietilestilbestrol/efeitos adversos , Dietilestilbestrol/uso terapêutico , Humanos , Hidrocortisona/metabolismo , Masculino , Pessoa de Meia-Idade
13.
Nihon Hinyokika Gakkai Zasshi ; 90(8): 741-4, 1999 Aug.
Artigo em Japonês | MEDLINE | ID: mdl-10487051

RESUMO

A 2,510 g female newborn was delivered by Cesarean section at 33 weeks gestation due to increasing volume of her huge bladder and bilateral hydronephrosis. Just after birth 190 ml of urine was drainaged by catheterization without difficulty. Voiding cystourethrography showed no VUR. She had no ureteral dilation, either. Urodynamic study revealed large bladder capacity and detrusor hypocontractility. Neither neurological nor gastrointestinal abnormality was detected neonatally. Clean intermitted catheterization was performed every 4 hours. At 12 months of her age she had no history of urinary tract infection. However, as she grew up with normal diet, severe constipation became apparent. This is a case of idiopathic intestinal pseudo-obstruction syndrome whose gastrointestinal symptom was masked in the newborn period. Attention should be paid for gastrointestinal tract as well as urinary tract when the body has congenital megacystis with unknown etiology.


Assuntos
Doenças Fetais/diagnóstico por imagem , Pseudo-Obstrução Intestinal/congênito , Ultrassonografia Pré-Natal , Doenças da Bexiga Urinária/diagnóstico por imagem , Feminino , Humanos , Hidronefrose/diagnóstico por imagem , Recém-Nascido , Doenças da Bexiga Urinária/patologia
14.
Clin Implant Dent Relat Res ; 1(2): 92-7, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-11359303

RESUMO

BACKGROUND: Clinical studies have reported a correlation between the surface roughness of implant abutments and the rate of supragingival and subgingival plaque formation. In order to maintain periimplant health, it is important to understand the relationship between abutment surface characteristics and plaque formation. PURPOSE: The aim of this study was to use high image resolution imaging techniques for analysis of implant abutment surface topography. MATERIALS AND METHODS: Five commercially available implant abutments (Brånemark, Nobel Biocide, AB, Goteborg, Sweden, Astra, Astra Tech AB, Mondal, Sweden, IMZ, Friatec AG, Mannheim, Germany, Steri-Oss, Denar Corp, Anaheim, Calif, USA, and POI, Kyocera Corp, Kyoto, Japan) were visually and quantitatively characterized using an atomic force microscope. RESULTS: Statistical analysis by analysis of variance and Fishers's Protected Least Significant Differences showed significant differences (p < .05) between arithmetic mean deviation values of surface relative to the center plane (Sa). Power spectral density analysis also was effective as a spacing parameter. Sectional profiles measured the exact length, depth, or height of the specific features on the images. CONCLUSIONS: Within the limits of this study, the Brånemark, Astra and IMZ abutments displayed turning marks in x direction from the procedure. The Steri-Oss abutment showed smoothest surface among the five abutments tested.


Assuntos
Dente Suporte , Implantes Dentários , Planejamento de Prótese Dentária , Análise de Variância , Microscopia de Força Atômica , Propriedades de Superfície
15.
Eur Urol ; 33 Suppl 3: 37-40, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9599736

RESUMO

OBJECTIVE(S): Two hundred and thirty-eight children (170 males, and 68 females) with nocturnal enuresis were retrospectively studied for lower urinary tract problems. Surgical correction of subclinical organic obstruction in the lower urinary tract was evaluated for the improvement of bed-wetting. METHODS: One hundred and fifty-five micturating cystourethrography (MCU), and 89 urodynamic studies were performed. Optic internal urethrotomy was done in a boy, and meatoplasty in a girl for urethral 'ring' stenosis (URS). RESULTS: Nocturnal enuresis was found in 153 cases and nocturnal enuresis associated with daytime enuresis in 67 cases. Vesicoureteral reflux was found in 30, URS in 42, and posterior urethral valve in 3 cases on MCU. Detrusor instability was recognized in 39.4% of 38 cases of nocturnal enuresis associated with daytime enuresis and in 25.0% of 51 cases of nocturnal enuresis. Surgery brought 73.8% improvement of bed-wetting in 42 cases. CONCLUSIONS: Surgical correction of subclinical obstruction in the lower urinary tract might contribute to the earlier resolution of bed-wetting in children with nocturnal and/or diurnal enuresis.


Assuntos
Enurese/etiologia , Obstrução Uretral/complicações , Adolescente , Criança , Pré-Escolar , Cistoscopia , Enurese/diagnóstico por imagem , Enurese/cirurgia , Feminino , Humanos , Masculino , Radiografia , Estudos Retrospectivos , Fatores Sexuais , Resultado do Tratamento , Uretra/diagnóstico por imagem , Obstrução Uretral/diagnóstico por imagem , Obstrução Uretral/cirurgia , Urodinâmica
16.
Diabetes Res Clin Pract ; 42(1): 65-70, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9884035

RESUMO

We studied 68 Japanese NIDDM patients (38 men and 30 women), aged 56.9+/-1.2 years (range 33-75 years), with a BMI of 23.1+/-0.5 kg/m2 without hypertension, dyslipidemia, and diabetic macroangiopathy for evaluating the relationship between serum soluble vascular cell adhesion molecule-1 (sVCAM-1) levels and the severity of diabetic retinopathy. Fundus examination was performed by an ophthalmologist using an ophthalmoscope, and the findings were graded as: (1) no signs of diabetic retinopathy (NDR), (2) background diabetic retinopathy (BDR), or (3) proliferative diabetic retinopathy (PDR). Serum sVCAM-1 levels were measured in duplicate by enzyme-linked immunosorbent assay using the soluble VCAM-1 KIT (R&D Systems Ltd., Ablingdon, Oxfordshire, UK). There was no difference in serum sVCAM-1 levels between patients with BDR (n = 17) and patients with NDR (n = 40) (1035.3+/-104.4 and 978.8+/-48.9 ng/ml, respectively, P = 0.8), but patients with PDR (n = 11) showed a significant increase of serum sVCAM-1 levels compared with patients with NDR (1281.8+/-166.3 and 978.8+/-48.9 ng/ml, respectively, P = 0.02). Although serum sVCAM-1 levels were correlated, not only with age but also with the known diabetic duration (r = 0.39, P = 0.001, and r = 0.40, P = 0.0007, respectively), age-adjusted sVCAM-1 levels were still significantly higher in the PDR group than in the NDR group. In contrast. serum sVCAM-1 levels were not related to the presence of diabetic nephropathy or HbA1c levels. Our results suggest that sVCAM-1 might be implicated in the development of the diabetic retinopathy, and measurement of serum sVCAM-1 levels in NIDDM patients maybe clinically useful for assessing the severity and possibly the activity of diabetic retinopathy.


Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Retinopatia Diabética/sangue , Molécula 1 de Adesão de Célula Vascular/sangue , Adulto , Idoso , Biomarcadores/sangue , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Creatinina/sangue , Diabetes Mellitus Tipo 2/sangue , Retinopatia Diabética/fisiopatologia , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Triglicerídeos/sangue
17.
J Pharm Pharmacol ; 49(9): 892-6, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9306257

RESUMO

Time-course of plasma concentration of unchanged drug of the dopamine DA1-receptor agonist (-)-(S)-4-(3,4-dihydroxyphenyl)-7,8-dihydroxy-1,2,3,4- tetrahydroisoquinoline hydrochloride hydrate (YM435), and its effects on blood pressure and renal blood flow were investigated in anaesthetized dogs. Continuous intravenous infusion of YM435 (0.1-3 micrograms kg-1 min-1) rapidly increased renal blood flow and lowered blood pressure in a dose-dependent manner. These effects remained generally stable throughout the infusion period. Following the start of infusion, plasma concentration of unchanged drug also rose rapidly and dose-dependently and remained virtually constant throughout the infusion period. A significant correlation was observed between log YM435 plasma concentration and the increase in renal blood flow (r = 0.93, P < 0.0001) and between the former and the reduction in blood pressure (r = 0.93, P < 0.0001). The present results indicate that YM435 produces renal vasodilatation and lowering of blood pressure in a dose-dependent manner and with rapid onset following continuous intravenous infusion, and that these effects are generally stable throughout the period of infusion. These haemodynamic effects of YM435 were in good agreement with the time-course of plasma concentration of unchanged drug.


Assuntos
Isoquinolinas/farmacologia , Receptores de Dopamina D1/agonistas , Tetra-Hidroisoquinolinas , Vasodilatadores/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Cães , Feminino , Isoquinolinas/sangue , Isoquinolinas/farmacocinética , Masculino , Receptores de Dopamina D1/efeitos dos fármacos , Circulação Renal/efeitos dos fármacos , Vasodilatadores/sangue , Vasodilatadores/farmacocinética
18.
Kokubyo Gakkai Zasshi ; 63(2): 354-74, 1996 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-8741520

RESUMO

Two hundred fifty-five solitary and 42 multiple cases of fibro-osseous lesions of the jaws, and 74 cases of sclerosing osteomyelitis were studied clinico-pathologically, in order to discuss the entity of peculiar cemental lesion with sequester-like appearance, which occurs mainly in the mandibular molar area of over middle-aged females. Four allied lesions, including the sequester-like cemental lesion, were revealed. They were provisionally designated sequestrated cemental masses, cemental masses, focal cemento-osseous dysplasia, and periapical cemental masses respectively, because no entities that were consistent with them could be found in the classifications of World Health Organization (WHO). The above- mentioned peculiar cemental lesion was equivalent to sequestrated cemental masses, which consist of sclerotic cementum and/or osteocementum with inflammation. Cemental masses and periapical cemental masses were related to sequestrated cemental masses. Focal cemento- osseous dysplasia was considered to be a counterpart of lesion which had been recently reported by Summerlin et al. In consideration of similarity and continuity of the histological and clinical findings, the four allied lesions were thought to be arranged in a continuous spectrum of fibro-cemento-osseous dysplasia of the jaws, along with periapical cemental dysplasia and florid cemento-osseous dysplasia that are mentioned in the WHO classification.


Assuntos
Cemento Dentário/patologia , Doenças Maxilomandibulares/patologia , Osteomielite/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
20.
Mutat Res ; 315(3): 229-37, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7526200

RESUMO

The XPA (xeroderma pigmentosum group A) gene encodes a protein of 273 amino acids with a zinc finger motif. The human XPA cDNA was placed in an Escherichia coli expression vector for the synthesis of the recombinant XPA protein. The molecular weight of the wild-type protein was about 40 kDa in SDS-PAGE. Microinjection of the wild-type protein specifically restored the defect of UV-induced unscheduled DNA synthesis in XP-A cells. Thus, the bacterially expressed XPA protein retains biochemical properties identical to those of natural sources. The wild-type protein binds preferentially to UV-, cis-diamminedichloroplatinum(II) (cisplatin)- or osmium tetroxide (OsO4)-damaged DNA as assayed by retention on nitrocellulose filters. In addition, the data from atomic absorption and UV-CD spectra revealed that the wild-type protein is a zinc metalloprotein with secondary structure. Furthermore, the mutant protein, of which the cysteine-103 residue in the zinc finger motif was replaced with serine, has a vastly different protein conformation resulting in a loss of XP-A correcting and DNA-binding activities. These findings indicate that the XPA protein is a zinc-binding protein with affinity for various DNA damages, and a cysteine residue in the C4-type zinc finger motif is indispensable for normal protein conformation.


Assuntos
Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Metaloproteínas/metabolismo , Zinco/análise , Aminoácidos/análise , Linhagem Celular , DNA/biossíntese , DNA Viral/efeitos da radiação , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Escherichia coli/genética , Humanos , Metaloproteínas/química , Metaloproteínas/genética , Microinjeções , Peso Molecular , Ligação Proteica , Conformação Proteica , Proteínas Recombinantes de Fusão/biossíntese , Raios Ultravioleta , Xeroderma Pigmentoso , Proteína de Xeroderma Pigmentoso Grupo A
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