Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Cureus ; 16(2): e54387, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38505445

RESUMO

Background Hypertension, or high blood pressure, is a common medical condition that affects a significant portion of the global population. It is a major risk factor for cardiovascular diseases (CVD), stroke, and kidney disorders. Objective The objective of this study is to create and validate a model that combines bootstrapping, ordered logistic regression, and multilayer feed-forward neural networks (MLFFNN) to identify and analyze the factors associated with hypertension patients who also have dyslipidemia. Material and methods A total of 33 participants were enrolled from the Hospital Universiti Sains Malaysia (USM) for this study. In this study, advanced computational statistical modeling techniques were utilized to examine the relationship between hypertension status and several potential predictors. The RStudio (Posit, Boston, MA) software and syntax were implemented to establish the relationship between hypertension status and the predictors. Results The statistical analysis showed that the developed methodology demonstrates good model fitting through the value of predicted mean square error (MSE), mean absolute deviance (MAD), and accuracy. To evaluate model fitting, the data in this study was divided into distinct training and testing datasets. The findings revealed that the results strongly support the superior predictive capability of the hybrid model technique. In this case, five variables are considered: marital status, smoking status, systolic blood pressure, fasting blood sugar levels, and high-density lipoprotein levels. It is important to note that all of them affect the hazard ratio: marital status (ß1, -17.12343343; p < 0.25), smoking status (ß2, 1.86069121; p < 0.25), systolic blood pressure (ß3, 0.05037332; p < 0.25), fasting blood sugar (ß4, -0.53880322; p < 0.25), and high-density lipoprotein (ß5, 5.38065556; p < 0.25). Conclusion This research aims to develop and extensively evaluate the hybrid approach. The statistical methods employed in this study using R language show that regression modeling surpasses R-squared values in predicting the mean square error. The study's conclusion provides strong evidence for the superiority of the hybrid model technique.

2.
Med J Malaysia ; 76(5): 734-736, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34508384

RESUMO

Pulmonary Tuberculosis (PTB) is an endemic disease in Malaysia and continues to cause great morbidity and mortality. However, the diagnosis and treatment may pose a challenge to the attending physician since other diseases such as melioidosis can mimic tuberculosis. Hence, the final diagnosis should be done thorough history of illness, physical examination, investigations, and interpretation of findings. We present here a case of a 27-year-old man who presented at our primary care clinic with underlying diabetes mellitus whose symptoms were suggestive of PTB, and who was treated with anti-tuberculosis but later his sputum grew culture Burkholderia pseudomallei.


Assuntos
Burkholderia pseudomallei , Melioidose , Tuberculose Pulmonar , Tuberculose , Adulto , Antibacterianos/uso terapêutico , Humanos , Masculino , Melioidose/diagnóstico , Melioidose/tratamento farmacológico , Escarro , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/tratamento farmacológico
3.
Malays J Pathol ; 43(2): 303-310, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34448794

RESUMO

Death-in-custody refers to the occurrence of death, while a person is under the custody of any enforcement agency. Their incidence often creates overwhelming public and media attention. Currently, there is no standardised definition of 'death-in-custody' in Malaysia and internationally. A crosssectional descriptive study was performed in the Department of Forensic Medicine Hospital Tuanku Ja'afar Seremban (HTJS) for a period of 24 months. Information on all custodial deaths registered at HTJS from January 2001 till December 2015 was selected from the in-house hospital death registration system. The definition of 'death-in-custody' used was guided by the recommendation by the 'Australian Royal Commission into Aboriginal Deaths in Custody' 1991 with few adjustments. Four custodial settings of interest (the police, prison, immigration depot for the illegal immigrant, and army custody) were studied. A total of 172 deaths-in-custody were collected, in which the majority of cases were natural deaths (84.88%), predominantly infective in nature (65.07%). Less than 1/6th of cases were unnatural deaths with more than 80% died from legal intervention. All custodial deaths were dominated by males (96.51%) with a mean and median age of 37 years. In terms of nationality, 52.91% of the deaths involved Malaysian citizens in which the 'Malay/Bumi' race outnumbered the other two main races. The most documented custodial deaths occurred in prison (44.19%) followed by immigration depots (38.37%) and police lock-ups (17.44%). This study provides a general overview of the pattern including the causes and the demographic profile involving death in custody in the Seremban district registered at HTJS.


Assuntos
Medicina Legal , Adulto , Austrália , Causas de Morte , Feminino , Hospitais , Humanos , Masculino , Polícia , Prisioneiros
4.
J Parasit Dis ; 45(2): 459-473, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34295046

RESUMO

The cytotoxicity of Acanthamoeba is yet to fully illustrate due to recalcitrant of Acanthamoeba during cyst stage. The formation of the trehalose layer at the cyst stage protects the inner components of this opportunist protozoan parasite. Trehalase from the Aspergillus niger (AnTre) activity on the cyst of Acanthamoeba was determined based on AnTre dose-response, morphological and protein changes. The interaction of the AnTre and trehalose was also visualized through docking simulation. Vacuolation of the cyst can be seen when observed under light microscopy. Membrane integrity assessment suggested possible hydrolization of the AnTre enzyme to trehalose membranes which based on acridine orange and propidium iodide staining. Surface morphology based on scanning electron microscopy revealed the formation of bulging structure that was also proved through cross sectioning observed by transmission electron microscopy. Loss of internal structure of the cysts was clearly observed. Other morphological distinction where loss of rigid shape due to the destruction of the endo- and ecto cyst layers. However, the protein profile exhibits change of trehalose layer as responses to AnTre treatment. The observed biological results were also supported by interaction simulation based on molecular docking between trehalose and AnTre enzyme. In conclusion, this enzymatic approach could be developed into selective and effective mechanism to control Acanthamoeba without affecting the host especially mammals due to the absence of trehalose elements in the tissues of mammals.

5.
Biopolymers ; 111(2): e23337, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31691964

RESUMO

The interaction between mefloquine (MEF), the antimalarial drug, and human serum albumin (HSA), the main carrier protein in blood circulation, was explored using fluorescence, absorption, and circular dichroism spectroscopic techniques. Quenching of HSA fluorescence with MEF was characterized as static quenching and thus confirmed the complex formation between MEF and HSA. Association constant values for MEF-HSA interaction were found to fall within the range of 3.79-5.73 × 104 M-1 at various temperatures (288, 298, and 308 K), which revealed moderate binding affinity. Hydrogen bonds and hydrophobic interactions were predicted to connect MEF and HSA together in the MEF-HSA complex, as deduced from the thermodynamic data (ΔS = +133.52 J mol-1 K-1 and ΔH = +13.09 kJ mol-1 ) of the binding reaction and molecular docking analysis. Three-dimensional fluorescence spectral analysis pointed out alterations in the microenvironment around aromatic amino acid (tryptophan and tyrosine) residues of HSA consequent to the addition of MEF. Circular dichroic spectra of HSA in the wavelength ranges of 200-250 and 250-300 nm hinted smaller changes in the protein's secondary and tertiary structures, respectively, induced by MEF binding. Noncovalent conjugation of MEF to HSA bettered protein thermostability. Site marker competitive drug displacement results suggested HSA Sudlow's site I as the MEF binding site, which was also supported by molecular docking analysis.


Assuntos
Antimaláricos/química , Mefloquina/química , Simulação de Acoplamento Molecular , Albumina Sérica Humana/química , Dicroísmo Circular , Humanos , Espectrometria de Fluorescência
6.
Malays J Pathol ; 41(2): 83-89, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31427544

RESUMO

INTRODUCTION: Stature estimation is population dependent, and population-specific regression equations should be generated for accurate anthropological assessments. Nevertheless, stature estimation data was inaccessible and limited in some of the South-East Asian countries. The systematic review was conducted to analyse the regression equations of stature estimations developed in South-East Asian region. MATERIALS AND METHODS: A systematic literature search was performed through SCOPUS database and Google Scholar from January till March 2018. All published articles which developed stature estimation from different types of bone, methods and type of statures (i.e. living stature, forensic stature and cadaveric stature) were included in this study. Risks of biases were also assessed. Population studies with no regression equations were excluded from the study. RESULTS: Seven studies that met the inclusion criteria were identified. In the South-East Asia region, regression equations for stature estimation were developed in Thailand and Malaysia. In these studies, bone measurements were done either by radiography, direct bone measurement, or palpation on body surface for anatomical bony prominence. All of these studies used various parts of bones for stature estimation. CONCLUSION: The most widely used regression equations for stature estimation in South-East Asian population were from the Thailand population. Further research is recommended to develop regression equations for other South-East Asian countries.


Assuntos
Estatura , Antropologia Forense , Povo Asiático , Feminino , Humanos , Masculino
7.
Geriatr Gerontol Int ; 19(3): 233-239, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30618211

RESUMO

AIM: The 36-month Long-Term Research Grant Scheme project: Towards Usual Aging - Neuroprotective Model for Healthy Longevity among Malaysian Elderly was designed to address multidimensional aspects including psychosocial, biophysical health, nutrition and dietary pattern, and auditory and visual function to highlight the magnitude of these associations in a single study. METHODS: A total of 2322 respondents aged ≥60 years were recruited at baseline using the multistage sampling method, followed up at 18 months and 36 months. RESULTS: Response rates at baseline, 18 months and 36 months were 87.8%, 77.3% and 67.1%, respectively. At baseline, the prevalence of successful aging, usual aging and mild cognitive impairment was 11%, 73% and 16%, respectively. The prevalence of single and multimorbidity at baseline were 25.9% and 50.3%, respectively. The incidence rates of mild cognitive impairment at 18 months and 36 months were 6.5 and 5.6 per 100 person-years. The incidence rates of multimorbidity at 18 months and 36 months were 23.7 and 21.5 per 100 person-years, respectively. CONCLUSIONS: The Long-Term Research Grant Scheme project: Towards Usual Aging study provides an opportunity to investigate the interactions between wide ranges of aspects of the older population in a nationally representative sample of the older population. Geriatr Gerontol Int 2019; 19: 233-239.


Assuntos
Disfunção Cognitiva/epidemiologia , Projetos de Pesquisa Epidemiológica , Longevidade , Idoso , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Multimorbidade
8.
Sultan Qaboos Univ Med J ; 18(4): e494-e500, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30988969

RESUMO

OBJECTIVES: Heart failure (HF) is a common clinical syndrome with an enormous impact on prognosis and lifestyle. Accordingly, rehabilitation measures need to be patient-specific and consider various sociocultural factors so as to improve the patient's quality of life (QOL). This study aimed to develop and validate a HF-specific QOL (HFQOL) questionnaire within a multicultural setting. METHODS: This study took place at the National Heart Institute and Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia, between March 2013 and March 2014. A self-administered 75-item HFQOL questionnaire was designed and administrated to 164 multi-ethnic Malaysian HF patients. Exploratory factor analysis was performed to assess the instrument's construct validity. Cronbach's alpha coefficients were used to determine internal consistency. RESULTS: A total of 33 out of 75 items were retained in the final tool. The HFQOL questionnaire had three common factors-psychological, physical-social and spiritual wellbeing-resulting in a cumulative percentage of total variance of 44.3%. The factor loading ranges were 0.450-0.718 for psychological wellbeing (12 items), 0.394-0.740 for physical-social wellbeing (14 items) and 0.449-0.727 for spiritual wellbeing (seven items). The overall Cronbach's alpha coefficient of the questionnaire was 0.82, with coefficients of 0.86, 0.88 and 0.79 for the psychological, physical-social and spiritual wellbeing subdomains, respectively. CONCLUSION: The HFQOL questionnaire was found to be a valid and reliable measure of QOL among Malaysian HF patients from various ethnic groups. Such tools may facilitate cardiac care management planning among multi-ethnic patients with HF.


Assuntos
Insuficiência Cardíaca/complicações , Psicometria/normas , Qualidade de Vida/psicologia , Idoso , Assistência à Saúde Culturalmente Competente/métodos , Feminino , Insuficiência Cardíaca/psicologia , Humanos , Malásia , Masculino , Pessoa de Meia-Idade , Psicometria/instrumentação , Psicometria/métodos , Reprodutibilidade dos Testes , Inquéritos e Questionários
9.
Front Microbiol ; 8: 1518, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28848527

RESUMO

Staphylococcus aureus infection is a common cause of mastitis, reducing milk yield, affecting animal welfare and causing huge economic losses within the dairy industry. In addition to the problem of acquired drug resistance, bacterial invasion into udder cells and the formation of surface biofilms are believed to reduce antibiotic efficacy, leading to treatment failure. Here, we investigated the antimicrobial activities of enrofloxacin, an antibiotic that is commonly used in mastitis therapy and polyhexamethylene biguanide (PHMB), an antimicrobial polymer. The antimicrobial activities were tested against intracellular S. aureus in infected Mac-T cells (host cells). Also, fluorescein-tagged PHMB was used to study PHMB uptake and localization with S. aureus within the infected Mac-T cells. Anti-biofilm activities were tested by treating S. aureus biofilms and measuring effects on biofilm mass in vitro. Enrofloxacin and PHMB at 15 mg/L killed between 42 to 92 and 99.9% of intracellular S. aureus, respectively. PHMB-FITC entered and colocalized with the intracellular S. aureus, suggesting direct interaction of the drug with the bacteria inside the host cells. Enrofloxacin and PHMB at 15 mg/L reduced between 10 to 27% and 28 to 37% of biofilms' mass, respectively. The half-maximal inhibitory concentrations (IC50) obtained from a cytotoxicity assay were 345 ± 91 and 21 ± 2 mg/L for enrofloxacin and PHMB, respectively; therefore, both compounds were tolerated by the host cells at high concentrations. These findings suggest that both antimicrobials are effective against intracellular S. aureus and can disrupt biofilm structures, with PHMB being more potent against intracellular S. aureus, highlighting the potential application of PHMB in mastitis therapy.

10.
Acta Trop ; 171: 138-140, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28359829

RESUMO

Mosquitoes are vectors of various human diseases in the tropics including yellow fever, dengue, malaria and West Nile virus. Mosquitoes can act as vectors between wildlife and humans, which is particularly important for diseases where wild animals serve as reservoirs of parasites in the absence of human infections. Research has mainly focused on the medical impacts of Anopheles, Aedes, Mansonia and Culex, however, very little attention has been directed towards other mosquito genera, especially those which act as vectors of diseases of wildlife. We have observed adults of Mimomyia (Etorleptiomyia) luzonensis (Ludlow, 1905) feeding on a toad, Ingerophrynus parvus, near an oil palm plantation settlement in Setia Alam, Selangor state, Peninsular Malaysia. Mimomyia is known to feed on reptiles and amphibians, and is a documented vector of several arboviruses, including West Nile virus. The observation of Mimomyia feeding on a common toad near a human settlement highlights a need to understand the relationships between mosquitoes, toads and humans from an ecological perspective. We report on-site observations of the feeding habit of Mimomyia; the first records from Malaysia.


Assuntos
Culicidae/fisiologia , Comportamento Alimentar/fisiologia , Animais , Bufonidae , Culicidae/virologia , Humanos , Malásia
11.
Clin Ter ; 168(2): e84-e87, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28383619

RESUMO

INTRODUCTION: Stature is one of the characteristics that could be used to identify human, besides age, sex and racial affiliation. This is useful when the body found is either dismembered, mutilated or even decomposed, and helps in narrowing down the missing person's identity. AIM: The main aim of the present study was to construct regression functions for stature estimation by using lower limb bones in the Malaysian population. MATERIALS AND METHODS: The sample comprised 87 adult individuals (81 males, 6 females) aged between 20 to 79 years. The parameters such as thigh length, lower leg length, leg length, foot length, foot height and foot breadth were measured. They were measured by a ruler and measuring tape. Statistical analysis involved independent t-test to analyse the difference between lower limbs in male and female. The Pearson's correlation test was used to analyse correlations between lower limb parameters and stature, and the linear regressions were used to form equations. The paired t-test was used to compare between actual stature and estimated stature by using the equations formed. RESULTS: Using independent t-test, there was a significant difference (p< 0.05) in the measurement between males and females with regard to leg length, thigh length, lower leg length, foot length and foot breadth. The thigh length, leg length and foot length were observed to have strong correlations with stature with p= 0.75, p= 0.81 and p= 0.69, respectively. Linear regressions were formulated for stature estimation. Paired t-test showed no significant difference between actual stature and estimated stature. CONCLUSIONS: It is concluded that regression functions can be used to estimate stature to identify skeletal remains in the Malaysia population.


Assuntos
Antropometria , Estatura/fisiologia , Extremidade Inferior/anatomia & histologia , Adulto , Idoso , Povo Asiático , Restos Mortais , Feminino , Pé/anatomia & histologia , Antropologia Forense , Humanos , Modelos Lineares , Malásia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
12.
World J Transplant ; 6(3): 532-41, 2016 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-27683631

RESUMO

The successful of transplantation is determined by the shared human leukocyte antigens (HLAs) and ABO blood group antigens between donor and recipient. In recent years, killer cell receptor [i.e., killer cell immunoglobulin-like receptor (KIR)] and major histocompatibility complex (MHC) class I chain-related gene molecule (i.e., MICA) were also reported as important determinants of transplant compatibility. At present, several different genotyping techniques (e.g., sequence specific primer and sequence based typing) can be used to characterize blood group, HLA, MICA and KIR and loci. These molecular techniques have several advantages because they do not depend on the availability of anti-sera, cellular expression and have greater specificity and accuracy compared with the antibody-antigen based typing. Nonetheless, these molecular techniques have limited capability to capture increasing number of markers which have been demonstrated to determine donor and recipient compatibility. It is now possible to genotype multiple markers and to the extent of a complete sequencing of the human genome using next generation sequencer (NGS). This high throughput genotyping platform has been tested for HLA, and it is expected that NGS will be used to simultaneously genotype a large number of clinically relevant transplantation genes in near future. This is not far from reality due to the bioinformatics support given by the immunogenetics community and the rigorous improvement in NGS methodology. In addition, new developments in immune tolerance based therapy, donor recruitment strategies and bioengineering are expected to provide significant advances in the field of transplantation medicine.

13.
Hum Immunol ; 77(4): 338-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26820937

RESUMO

Cytokines are involved in immune responses and the pathogenesis of various diseases. Allelic variations within the genes coding for various ∼30 kDa cytokine protein/glycoproteins have been reported for many populations and have been the subjects of many ancestry and health analyses. In this study, we typed 22 single nucleotide polymorphisms (SNPs) in 13 cytokine genes of 165 Orang Asli individuals by using sequence specific primer-polymerase chain reaction (SSP-PCR) assay. The volunteers came from all across the Peninsular of Malaysia and belong to six Orang Asli subgroups; Batek, Kensiu, Lanoh, Che Wong, Semai and Orang Kanaq. Here we report our general findings and original genotype data and their associated analyses (Hardy-Weinberg proportions, estimation of allele and haplotype frequencies) can be found in the supplementary files and will be held at Allele Frequency Net Database (AFND).


Assuntos
Citocinas/genética , Etnicidade/genética , Polimorfismo de Nucleotídeo Único , Alelos , Frequência do Gene , Haplótipos , Humanos , Malásia
14.
Ir J Med Sci ; 182(4): 697-701, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23645548

RESUMO

AIMS: To study the nature of the tumours managed in the Irish population. METHODS: This audit research was completed via a retrospective medical review on 200 patients with CNS tumours managed in a tertiary care centre between 2008 and 2009. RESULTS: The mean age was 53 years. The male:female ratio was 2:1. The majority were glioblastomas and astrocytomas. Grade IV tumours were predominant (65.5 %). Headaches (37 %), motor weakness (32 %) and seizures (25.5 %) were the highest presentations. The commonest sites affected were the left parietal and left temporal lobes. There were 17.5 % operative morbidities with motor weakness (22.9 %), seizure (14.3 %) and thrombo-embolism (14.3 %) dominating and significant association to surgical radicality (p = 0.041). 3.5 % operative mortalities were reported. 52.5 and 62.5 % of patients received adjuvant chemotherapy and radiotherapy, respectively. CONCLUSIONS: Patients with CNS tumours typically had multiple presentations. More extensive surgical resection was associated with higher postoperative morbidities (p = 0.041). The 30-day postoperative morbidity (17.5 %) and mortality (3.5 %) were concordant with the currently available literature.


Assuntos
Astrocitoma/cirurgia , Neoplasias do Sistema Nervoso Central/cirurgia , Glioblastoma/cirurgia , Procedimentos Neurocirúrgicos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Astrocitoma/complicações , Astrocitoma/mortalidade , Neoplasias do Sistema Nervoso Central/complicações , Neoplasias do Sistema Nervoso Central/mortalidade , Quimioterapia Adjuvante , Criança , Pré-Escolar , Feminino , Glioblastoma/complicações , Glioblastoma/mortalidade , Cefaleia/etiologia , Humanos , Lactente , Irlanda , Masculino , Auditoria Médica , Pessoa de Meia-Idade , Doença dos Neurônios Motores/etiologia , Gradação de Tumores , Procedimentos Neurocirúrgicos/efeitos adversos , Procedimentos Neurocirúrgicos/mortalidade , Radioterapia Adjuvante , Estudos Retrospectivos , Convulsões/etiologia , Centros de Atenção Terciária , Tromboembolia/etiologia , Resultado do Tratamento , Adulto Jovem
15.
J Dent Res ; 92(1): 51-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23114032

RESUMO

The discovery that dental pulp stem cells are capable of differentiating into endothelial cells raises the exciting possibility that these cells can be a single source of odontoblasts and vascular networks in dental tissue engineering. The purpose of this study was to begin to define signaling pathways that regulate endothelial differentiation of SHED. Stem cells from exfoliated deciduous teeth (SHED) exposed to endothelial growth medium (EGM-2MV) supplemented with vascular endothelial growth factor (VEGF) differentiated into VEGFR2-positive and CD31-positive endothelial cells in vitro. In vivo, VEGFR1-silenced SHED seeded in tooth slice/ scaffolds and transplanted into immunodeficient mice showed a reduction in human CD31-positive blood vessels as compared with controls (p = 0.02). Exposure of SHED to EGM2-MV supplemented with VEGF induced potent activation of ERK and Akt signaling, while it inhibited phosphorylation of STAT3. Notably, genetic (MEK1 silencing) or chemical (U0126) inhibition of ERK signaling restored constitutive STAT3 phosphorylation and inhibited the differentiation of SHED into endothelial cells. Collectively, analysis of these data unveiled the VEGF/MEK1/ERK signaling pathway as a key regulator of the endothelial differentiation of dental pulp stem cells.


Assuntos
Polpa Dentária/citologia , Células Endoteliais/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Células-Tronco/fisiologia , Dente Decíduo/citologia , Animais , Vasos Sanguíneos/imunologia , Butadienos/farmacologia , Técnicas de Cultura de Células , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Meios de Cultura , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inativação Gênica/fisiologia , Humanos , MAP Quinase Quinase 1/genética , MAP Quinase Quinase Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Knockout , Camundongos SCID , Nitrilas/farmacologia , Proteína Oncogênica v-akt/efeitos dos fármacos , Fosforilação , Molécula-1 de Adesão Celular Endotelial a Plaquetas/análise , Fator de Transcrição STAT3/antagonistas & inibidores , Alicerces Teciduais , Fator A de Crescimento do Endotélio Vascular/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/análise
16.
Int J Oral Maxillofac Surg ; 41(9): 1090-6, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22260789

RESUMO

A refinement technique is proposed for developing finite element models capable of simulating peri-implant bone conditions for bone types II, III, and IV at various degrees of osseointegration. The refined models feature a transition region between bone (cortical and cancellous) and implant and designate it partially to fully osseointegrated by assigning corresponding fractions of the bulk bone's elastic properties to this region. Bone is assumed to be transversely isotropic. The refined technique is implemented in a case study, in which osseointegrated (25-100%) peri-implant bone, type II, III, or IV with an implant attached, is loaded with a 100 MPa occlusal load. The biomechanics of this peri-implant bone was simulated and analysed. Results showed that the less dense bone must support higher stress and strain, especially at the cortical region. Higher degree of osseointegration induced higher stress but lower strain. Both the bone type and the osseointegration condition significantly affected the stress-strain relation. For minimum stress and strain, denser and more osseointegrated peri-implant bone is desirable. When bone failure criteria were set, based on the yield strength and strain of the bone, a higher degree of osseointegration was needed for the less dense peri-implant bone to be considered safe.


Assuntos
Desenho Assistido por Computador , Implantação Dentária Endóssea/métodos , Planejamento de Prótese Dentária/métodos , Osseointegração , Zigoma/cirurgia , Perda do Osso Alveolar/complicações , Fenômenos Biomecânicos , Simulação por Computador , Projeto do Implante Dentário-Pivô , Análise de Elementos Finitos , Humanos , Doenças Maxilares/complicações , Modelos Anatômicos
17.
Proc Inst Mech Eng H ; 225(10): 1015-20, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22204123

RESUMO

Tensile tests were conducted on polycaprolactone at various strain rates and temperatures. Focusing on the mechanical properties within only the small-strain elastic region, i.e. up to the inflection point in the stress-strain diagram, it was found that strain rate and temperature had significant effects on the polymer. This finding implies that the effects of strain rate and temperature on the elastic properties of polycaprolactone should be considered in the design and manufacture of rigidity-sensitive, load-bearing applications, including use as biomaterial for scaffolds in tissue engineering applications.


Assuntos
Elasticidade , Poliésteres , Temperatura , Resistência à Tração , Teste de Materiais/métodos
18.
Cytometry A ; 69(10): 1077-85, 2006 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-16924636

RESUMO

BACKGROUND: Nuclear texture analysis measures phenotypic changes in chromatin distribution within a cell nucleus, while the alkaline Comet assay is a sensitive method for measuring the extent of DNA breakage in individual cells. The authors aim to use both methods to provide information about the sensitivity of cells to ionizing radiation. METHODS: The alkaline Comet assay was performed on six human bladder carcinoma cell lines and one human urothelial cell line exposed to gamma-radiation doses from 0 to 10 Gy. Nuclear chromatin texture analysis of 40 features was then performed in the same cell lines exposed to 0, 2, and 6 Gy to explore if nuclear phenotype was related to radiation sensitivity. RESULTS: Comet assay results demonstrated that the cell lines exhibited different levels of radiosensitivity and could be divided into a radiosensitive and a radioresistant group at >6 Gy. Using stepwise discriminant analysis, a subset of important nuclear texture features that best discriminated between sensitive and resistant cell lines were identified A classification function, defined using these features, correctly classified 81.75% of all cells into their radiosensitive or radioresistant groups based on their pretreatment chromatin phenotype. Posttreatment chromatin changes also varied between cell lines, with sensitive cell lines showing a relaxed chromatin conformation following radiation, whereas resistant cell lines exhibited chromatin condensation. CONCLUSIONS: The authors conclude that the alkaline Comet assay and nuclear texture methodologies may prove to be valuable aids in predicting the response of tumor cells to radiotherapy.


Assuntos
Raios gama , Tolerância a Radiação , Bexiga Urinária/efeitos da radiação , Linhagem Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Núcleo Celular/efeitos da radiação , Cromatina/metabolismo , Ensaio Cometa , Quebras de DNA , Relação Dose-Resposta à Radiação , Humanos , Bexiga Urinária/citologia , Urotélio/citologia , Urotélio/efeitos da radiação
19.
Ann R Coll Surg Engl ; 86(2): 125-7, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15005933

RESUMO

OBJECTIVE: To determine the seniority and career intentions of doctors in posts recognised for basic surgical training in the Northern Region of England and to relate it to the number of specialist registrar posts available. METHODS: Postal questionnaire to and telephone interviews with 270 doctors. The main outcome measures were: demographic details, career stage, and intentions regarding subspecialties of choice. RESULTS: Of the post-holders, 171 (63%) intended to pursue a surgical career and, of these, 69% (118/171) were graduates of British universities. Of these 171, 28% (48) were uncertain of their subspecialty of choice and 10% (17) intended to work abroad. The overall ratio for SHO:SpR posts was 1.6:1 for this region and 40% of all basic surgical trainees were in favour of a specialist training programme after PRHO. CONCLUSIONS: Planning for surgical training and workforce needs to be supported by information about trainees' career plans and prospects.


Assuntos
Escolha da Profissão , Cirurgia Geral/educação , Mobilidade Ocupacional , Inglaterra , Humanos , Corpo Clínico Hospitalar , Inquéritos e Questionários
20.
Radiat Res ; 159(1): 49-56, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12492368

RESUMO

The alkaline single-cell gel electrophoresis (comet) assay can be combined with fluorescence in situ hybridization (FISH) methodology to investigate the localization of specific gene domains within an individual cell. The position of the fluorescent hybridization spots in the comet head or tail indicates whether the sequence of interest lies within or in the vicinity of a damaged region of DNA. In this study, we used the comet-FISH assay to examine initial DNA damage and subsequent repair in the TP53 gene region of RT4 and RT112 bladder carcinoma cells after 5 Gy gamma irradiation. In addition to standard comet parameter measurements, the number and location of TP53 hybridization spots within each comet was recorded at each repair time. The results indicate that the rate of repair of the TP53 gene region was fastest during the first 15 min after damage in both cell lines. When compared to overall genomic repair, the repair of the TP53 gene region was observed to be significantly faster during the first 15 min and thereafter followed a rate similar to that for the overall genome. The data indicate that the TP53 domain in RT4 and RT112 cells is repaired rapidly after gamma irradiation. Furthermore, this repair may be preferential compared to the repair of overall genomic DNA, which gives a measure of the average DNA repair response of the whole genome. We suggest that the comet-FISH assay has considerable potential in the study of gene-specific repair after DNA damage.


Assuntos
Dano ao DNA , Reparo do DNA/efeitos da radiação , Genes p53/efeitos da radiação , Neoplasias da Bexiga Urinária/genética , Ensaio Cometa/métodos , Raios gama , Humanos , Hibridização in Situ Fluorescente/métodos , Células Tumorais Cultivadas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...