Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69
Filtrar
1.
J Mech Behav Biomed Mater ; 140: 105723, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36821908

RESUMO

Poly(glycolide-co-caprolactone) (PGCL) has become a novice to the bioresorbable suture owing to the synergistic properties taken from the homo-polyglycolide (PGA) and polycaprolactone (PCL) such as excellent bioresorption and flexibility. In addition to under conventional monotonic loading, the understanding of mechanical responses of PGCL copolymers under complex loading conditions such as cyclic and stress relaxation is crucial for its application as a surgical suture. Consequently, the present work focuses on evaluating the mechanical responses of PGCL sutures under monotonic, cyclic, and stress relaxation loading conditions. Under monotonic loading, the stress-strain behavior of the PGCL suture was found to be non-linear with noticeable strain-rate dependence. Under cyclic loading, inelastic responses including stress-softening, hysteresis and permanent set were observed. During cyclic loading, both stress-softening and hysteresis were found to increase with the maximum strain. In multi-step stress relaxation, the PGCL sutures were observed to exhibit a strong viscoelastic response. In an attempt to describe the relationship between the stress-relaxation and strain-induced crystallization (SIC) occurring during the loading and relaxation processes, a schematic illustration of the conformational change of polymer chains in PGCL sutures was proposed in this work. Results showed that SIC was dependent on the strain level as well as the loading and relaxation durations. The inelastic phenomena observed in PGCL sutures can be thus correlated to the combined effect of stress relaxation and SIC.


Assuntos
Implantes Absorvíveis , Elastina , Ácido Poliglicólico/química , Suturas , Estresse Mecânico , Resistência à Tração
2.
Sci Rep ; 11(1): 21055, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34702838

RESUMO

Aspergillus fumigatus is a fungal pathogen whose effects can be debilitating and potentially fatal in immunocompromised patients. Current drug treatment options for this infectious disease are limited to just a few choices (e.g. voriconazole and amphotericin B) and these themselves have limitations due to potentially adverse side effects. Furthermore, the likelihood of the development of resistance to these current drugs is ever present. Thus, new treatment options are needed for this infection. A new potential antifungal drug target is acetohydroxyacid synthase (AHAS; EC 2.2.1.6), the first enzyme in the branched chain amino acid biosynthesis pathway, and a target for many commercial herbicides. In this study, we have expressed, purified and characterised the catalytic subunit of AHAS from A. fumigatus and determined the inhibition constants for several known herbicides. The most potent of these, penoxsulam and metosulam, have Ki values of 1.8 ± 0.9 nM and 1.4 ± 0.2 nM, respectively. Molecular modelling shows that these compounds are likely to bind into the herbicide binding pocket in a mode similar to Candida albicans AHAS. We have also shown that these two compounds inhibit A. fumigatus growth at a concentration of 25 µg/mL. Thus, AHAS inhibitors are promising leads for the development of new anti-aspergillosis therapeutics.


Assuntos
Acetolactato Sintase , Antifúngicos/química , Aspergillus fumigatus/enzimologia , Proteínas Fúngicas , Herbicidas/química , Pirimidinas/química , Sulfonamidas/química , Triazóis/química , Uridina/análogos & derivados , Acetolactato Sintase/antagonistas & inibidores , Acetolactato Sintase/química , Candida albicans/enzimologia , Proteínas Fúngicas/antagonistas & inibidores , Proteínas Fúngicas/química , Uridina/química
3.
Artigo em Inglês | MEDLINE | ID: mdl-34098488

RESUMO

While the processes governing docosahexaenoic acid (DHA) trafficking across the blood-brain barrier have been elucidated, factors governing DHA uptake into microglia, an essential step for this fatty acid to exert its anti-inflammatory effects, are unknown. This study assessed the mRNA and protein expression of fatty acid-binding proteins (FABPs) and fatty acid transport proteins (FATPs) in mouse BV-2 cells and their mRNA expression in primary mouse microglia. The microglial uptake of DHA-d5, a surrogate of DHA, was assessed by LC-MS/MS following interventions including temperature reduction, silencing of various FABP isoforms, competition with DHA, and metabolic inhibition. It was found that DHA-d5 uptake at 4°C was 39.6% lower than at 37°C, suggesting that microglial uptake of DHA-d5 likely involves passive and/or active uptake mechanisms. Of all FABP and FATP isoforms probed, only FABP3, FABP4, FABP5, FATP1, and FATP4 were expressed at both the mRNA and protein level. Silencing of FABP3, FABP4, and FABP5 resulted in no change in cellular DHA-d5 uptake, nor did concomitant DHA administration or the presence of 0.1% sodium azide/50 mM 2-deoxy-D-glucose. This study is the first to identify the presence of FABPs and FATPs in mouse microglia, albeit these proteins are not involved in the microglial uptake of DHA-d5.


Assuntos
Barreira Hematoencefálica/metabolismo , Ácidos Docosa-Hexaenoicos/metabolismo , Proteínas de Transporte de Ácido Graxo/metabolismo , Proteínas de Ligação a Ácido Graxo/metabolismo , Microglia/metabolismo , Animais , Deutério , Proteína 3 Ligante de Ácido Graxo/genética , Proteína 3 Ligante de Ácido Graxo/metabolismo , Proteínas de Transporte de Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/genética , Camundongos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo
4.
J Hazard Mater ; 407: 124365, 2021 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-33162238

RESUMO

Non-edible bio-oil derived from lignocellulosic biomass could be used as environmentally friendly lubricant-ester base stock for maritime and road-type transportations. However, the use of crude bio-oil with highly oxygenated compounds required further upgrading to yield ester that mimicked the characteristics of Group V base oil (polyolesters). In this study, bio-oil based polyolesters was produced via esterification using green biopolymer alginate acid catalyst (Al-Alg). The bio-oil compounds used were acetic acid (AcA), propionic acid (PrA) and levulinic acid (LA), while polyols such as neopentyl glycol (NPG), trimethylolpropane (TMP) and pentaerythritol (PE) were used. Optimization studies revealed that NPG-PrA ester gave the best ester purity of 100%, with 95% of diester selectivity under optimum conditions of 15 wt% Al-Alg, 8 h, 6:1 PrA:NPG and 140 °C. The produced polyolesters showed potential lube characteristics with viscosity index of 76, kinematic viscosity of 2.3 mm2 s-1 at 40 °C and oxidative induction time of 15 min at 100 °C. Furthermore, a reusability study of the Al-Alg catalyst indicated high NPG-PrA diester selectivity (above 90%) for 8 consecutive cycles. The physico-chemical properties of spent Al-Alg catalyst were also discussed.


Assuntos
Óleos de Plantas , Polifenóis , Biocombustíveis , Biomassa , Catálise , Esterificação , Ésteres
5.
Cytopathology ; 29(4): 343-348, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29683536

RESUMO

INTRODUCTION: To assess our practice using the recently developed standardised classification system designated The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) and to ascertain the rates of malignancy for each category by means of a retrospective study. METHODS: All salivary gland FNAC samples received between 1 January 2013 and 31 December 2015 were retrospectively assigned a diagnostic category code from the MSRSGC. Cytology results were correlated with subsequent histology (where available), and clinical and radiological follow up. RESULTS: A total of 287 salivary gland FNA samples were received from 272 patients. The specimens were classified as non-diagnostic (21.3%), non-neoplastic (22%), atypia of undetermined significance (2.4%), neoplasm benign (36.9%), neoplasm of uncertain malignant potential (5.2%), suspicious for malignancy (1.7%) and malignant (10.5%; low grade 1.4% and high grade 9.1%). Histological and clinical/radiological follow up was available for 138 (48.1%) specimens, clinical/radiological follow up only for 145 (50.5%) and no follow up for the remaining four (1.4%) samples. The risk of malignancy for each category was non-diagnostic (8.5%), non-neoplastic (1.6%), atypia of undetermined significance (0%), neoplasm benign (1.9%), neoplasm of uncertain malignant potential (26.7%), suspicious for malignancy (100%) and malignant (100%). CONCLUSIONS: The MSRSGC appears to be a useful tool to guide clinical management and provide an indication of possible risk of malignancy. We favour implementing use of these categories in our reporting practice with a future re-evaluation to assess maintenance of service quality as well as the clinical utility of this reporting system.


Assuntos
Biópsia por Agulha Fina/métodos , Citodiagnóstico/classificação , Doenças das Glândulas Salivares/patologia , Glândulas Salivares/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Técnicas Histológicas , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
6.
Am J Otolaryngol ; 39(2): 247-252, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29336902

RESUMO

INTRODUCTION: Jugular bulb and sigmoid sinus anomalies are well-known causes of vascular pulsatile tinnitus. Common anomalies reported in the literature include high-riding and/or dehiscent jugular bulb, and sigmoid sinus dehiscence. However, cases of pulsatile tinnitus due to diverticulosis of the jugular bulb or sigmoid sinus are less commonly encountered, with the best management option yet to be established. In particular, reports on surgical management of pulsatile tinnitus caused by jugular bulb diverticulum have been lacking in the literature. OBJECTIVES: To report two cases of pulsatile tinnitus with jugular bulb and/or sigmoid sinus diverticulum, and their management strategies and outcomes. In this series, we describe the first reported successful case of pulsatile tinnitus due to jugular bulb diverticulum that was surgically-treated. SUBJECTS AND METHODS: Two patients diagnosed with either jugular bulb and/or sigmoid sinus diverticulum, who had presented to the Otolaryngology clinic with pulsatile tinnitus between 2016 and 2017, were studied. Demographic and clinical data were obtained, including their management details and clinical outcomes. RESULTS: Two cases (one with jugular bulb diverticulum and one with both sigmoid sinus and jugular bulb diverticula) underwent surgical intervention, and both had immediate resolution of pulsatile tinnitus post-operatively. This was sustained at subsequent follow-up visits at the outpatient clinic, and there were no major complications encountered for both cases intra- and post-operatively. CONCLUSION: Transmastoid reconstruction/resurfacing of jugular bulb and sigmoid sinus diverticulum with/without obliteration of the diverticulum is a safe and effective approach in the management of bothersome pulsatile tinnitus arising from these causes.


Assuntos
Malformações Vasculares do Sistema Nervoso Central/complicações , Cavidades Cranianas/anormalidades , Divertículo/complicações , Veias Jugulares/anormalidades , Procedimentos Cirúrgicos Otorrinolaringológicos/métodos , Zumbido/etiologia , Adulto , Malformações Vasculares do Sistema Nervoso Central/diagnóstico , Divertículo/diagnóstico , Feminino , Humanos , Veias Jugulares/diagnóstico por imagem , Pessoa de Meia-Idade , Terapia Trombolítica , Zumbido/diagnóstico , Zumbido/cirurgia , Tomografia Computadorizada por Raios X
7.
Physiol Res ; 65(6): 1053-1058, 2016 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-27539106

RESUMO

The endothelial barrier function is tightly controlled by a broad range of signaling cascades including nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway. It has been proposed that disturbances in NO and cGMP production could interfere with proper endothelial barrier function. In this study, we assessed the effect of interferon-gamma (IFN-gamma), a pro-inflammatory cytokine, on NO and cGMP levels and examined the mechanisms by which NO and cGMP regulate the IFN-gamma-mediated HUVECs hyperpermeability. The flux of fluorescein isothiocyanate-labeled dextran across cell monolayers was used to study the permeability of endothelial cells. Here, we found that IFN-gamma significantly attenuated basal NO concentration and the increased NO levels supplied by a NO donor, sodium nitroprusside (SNP). Besides, application of IFN-gamma also significantly attenuated both the basal cGMP concentration and the increased cGMP production donated by a cell permeable cGMP analogue, 8-bromo-cyclic GMP (8-Br-cGMP). In addition, exposure of the cell monolayer to IFN-gamma significantly increased HUVECs basal permeability. However, L-NAME pretreatment did not suppress IFN-gamma-induced HUVECs hyperpermeability. L-NAME pretreatment followed by SNP or SNP pretreatment partially reduced IFN-gamma-induced HUVECs hyperpermeability. Pretreatment with a guanylate cyclase inhibitor, 6-anilino-5,8-quinolinedione (LY83583), led to a further increase in IFN-gamma-induced HUVECs hyperpermeability. The findings suggest that the mechanism underlying IFN-gamma-induced increased HUVECs permeability is partly related to the inhibition of NO production.


Assuntos
Permeabilidade Capilar/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Interferon gama/farmacologia , Óxido Nítrico/metabolismo , Permeabilidade da Membrana Celular , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , GMP Cíclico/farmacologia , Inibidores Enzimáticos/farmacologia , Feminino , Guanilato Ciclase/antagonistas & inibidores , Humanos , NG-Nitroarginina Metil Éster/farmacologia , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia
8.
Asian J Neurosurg ; 11(3): 316, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27366276

RESUMO

Burr-hole drainage of chronic subdural hematomas are routine operative procedures done by neurosurgical residents. Common postoperative complications include acute epidural and/or subdural bleeding, tension pneumocephalus, intracranial hematomas and ischemic cerebral infarction. We report an interesting post-operative complication of a 'subarachnoid cyst' after burr-hole evacuation of a chronic subdural hematoma. The authors hypothesize that the 'cyst' is likely secondary to the splitting of the adjacent neomembrane within its arachnoid-brain interface by iatrogenic irrigation of the subdural space. Over time, this 'cyst' develops into an area of gliosis which eventually causes long-term scar epilepsy in the patient. As far as we are aware, this is the first complication of such a 'subarachnoid cyst' post burr-hole drainage reported in the literature.

9.
Med J Malaysia ; 71(2): 83-4, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-27326951

RESUMO

Abdominal pain with dengue fever can be a diagnostic challenge. Typically, pain is localised to the epigastric region or associated with hepatomegaly. Patients can also present with acute abdomen. We report a case of a girl with dengue fever and right iliac fossa pain. The diagnosis of acute appendicitis was made only after four days of admission. An appendicular mass and a perforated appendix was noted during appendectomy. The patient recovered subsequently. Features suggestive of acute appendicitis are persistent right iliac fossa pain, localised peritonism, persistent fever and leucocytosis. Repeated clinical assessment is important to avoid missing a concurrent diagnosis like acute appendicitis.


Assuntos
Apendicectomia , Apendicite/complicações , Dengue/complicações , Dor Abdominal , Doença Aguda , Apendicite/cirurgia , Criança , Diagnóstico Diferencial , Feminino , Humanos
10.
Med J Malaysia ; 70(4): 259-62, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26358026

RESUMO

Isolated fallopian tube torsion is an uncommon diagnosis. It is particularly rare in the paediatric and post-menopausal age groups. It lacks pathognomonic symptoms, signs and imaging findings, yet each of these diagnostic steps plays a crucial role in early diagnosis. We describe two cases of isolated fallopian tube torsion in prepubertal females.

11.
Public Health ; 129(11): 1471-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26296847

RESUMO

OBJECTIVES: Fever screening systems, such as Infrared Thermal Detection Systems (ITDS), have been used for rapid identification of potential cases during respiratory disease outbreaks for public health management. ITDS detect a difference between the subject and ambient temperature, making deployment in hot climates more challenging. This study, conducted in Singapore, a tropical city, evaluates the accuracy of three different ITDS for fever detection compared with traditional oral thermometry and self-reporting in a clinical setting. STUDY DESIGN: This study is a prospective operational evaluation conducted in the Singapore military on all personnel seeking medical care at a high-volume primary healthcare centre over a one week period in February 2014. METHODS: Three ITDS, the STE Infrared Fever Screening System (IFSS), the Omnisense Sentry MKIII and the handheld Quick Shot Infrared Thermoscope HT-F03B, were evaluated. Temperature measurements were taken outside the healthcare centre, under a sheltered walkway and compared to oral temperature. Subjects were asked if they had fever. RESULTS: There were 430 subjects screened, of whom 34 participants (7.9%) had confirmed fever, determined by oral thermometer measurement. The handheld infrared thermoscope had a very low sensitivity (29.4%), but a high specificity (96.8%). The STE ITDS had a moderate sensitivity (44.1%), but a very high specificity (99.1%). Self-reported fevers showed good sensitivity (88.2%) and specificity (93.9%). The sensitivity of the Omnisense ITDS (89.7%) was the highest among the three methods with good specificity (92.0%). CONCLUSION: The new generation Omnisense ITDS displayed a relatively high sensitivity and specificity for fever. Though it has a lower sensitivity, the old generation STE ITDS system showed a very high specificity. Self-reporting of fever was reliable. The handheld thermograph should not be used as a fever-screening tool under tropical conditions.


Assuntos
Febre/diagnóstico , Raios Infravermelhos , Programas de Rastreamento/instrumentação , Medicina Tropical , Temperatura Corporal , Feminino , Humanos , Masculino , Militares/estatística & dados numéricos , Estudos Prospectivos , Sensibilidade e Especificidade , Singapura , Adulto Jovem
12.
J Hum Nutr Diet ; 28(6): 623-35, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25808062

RESUMO

BACKGROUND: The benefits of short-term oral nutritional supplementation (ONS) in undernourished children are well-established. The benefits of long-term ONS in promoting longitudinal growth and health in children who are at risk of undernutrition have not been reported previously. METHODS: In this 48-week prospective, single-arm, multicentre trial, 200 Filipino children aged 3-4 years with weight-for-height percentiles from 5th to 25th (WHO Child Growth Standards) were enrolled. Parents received dietary counselling at baseline, and at weeks 4 and 8. Two servings of ONS (450 mL) were consumed daily, providing 450 kcal, 13.5 g protein and micronutrients. Weight, height, dietary intake using 24-h dietary recalls, and physical activity and appetite using the visual analogue scales were assessed at baseline and weeks 4, 8, 16, 24, 32, 40 and 48. The number of sick days for acute illnesses was collected over the study period. RESULTS: At baseline, mean age was 41.2 months with 50% being male. Weight-for-height percentiles showed the greatest increase in the first 4 weeks (12.1 and 12.8 percentiles, respectively, P < 0.0001) and remained significantly higher than baseline (P < 0.0001) but were relatively stable from week 4 onwards. Height-for-age percentiles increased steadily over time and became significantly higher than baseline from week 24 onwards (P < 0.0001). Appetite and physical activity scores at all post-baseline visits improved from baseline (P < 0.0001), and a reduction in the number of sick days from week 16 onwards was also observed (P < 0.0001). Higher parental education level, being male and higher baseline weight-for-height percentiles were significantly associated with higher ponderal and linear growth over time in repeated measures analysis of covariance. CONCLUSIONS: Intervention consisting of initial dietary counselling and continued ONS helped sustain normal growth after a catch-up growth in nutritionally at-risk children.


Assuntos
Estatura/fisiologia , Peso Corporal/fisiologia , Desenvolvimento Infantil/fisiologia , Transtornos da Nutrição Infantil/prevenção & controle , Dieta/estatística & dados numéricos , Suplementos Nutricionais/estatística & dados numéricos , Transtornos da Nutrição Infantil/dietoterapia , Pré-Escolar , Dieta/métodos , Ingestão de Energia , Feminino , Humanos , Masculino , Filipinas , Estudos Prospectivos
13.
Mater Sci Eng C Mater Biol Appl ; 34: 345-53, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24268268

RESUMO

The piezoelectric response from ß-phase poly(vinylidene fluoride) (PVDF) can potentially be exploited for biomedical application. We hypothesized that α and ß-phase PVDF exert direct but different influence on cellular behavior. α- and ß-phase PVDF films were synthesized through solution casting and characterized with FT-IR, XRD, AFM and PFM to ensure successful fabrication of α and ß-phase PVDF films. Cellular evaluation with L929 mouse fibroblasts over one-week was conducted with AlamarBlue® metabolic assay and PicoGreen® proliferation assay. Immunostaining of fibronectin investigated the extent and distribution of extracellular matrix deposition. Image saliency analysis quantified differences in cellular distribution on the PVDF films. Our results showed that ß-phase PVDF films with the largest area expressing piezoelectric effect elicited highest cell metabolic activity at day 3 of culture. Increased fibronectin adsorption towards the cell-material interface was shown on ß-phase PVDF films. Image saliency analysis showed that fibroblasts on ß-phase PVDF films were more homogeneously distributed than on α-phase PVDF films. Taken collectively, the different molecular packing of α and ß-phase PVDF resulted in differing physical properties of films, which in turn induced differences in cellular behaviors. Further analysis of how α and ß-phase PVDF may evoke specific cellular behavior to suit particular application will be intriguing.


Assuntos
Materiais Biocompatíveis/farmacologia , Fibroblastos/citologia , Fibroblastos/metabolismo , Fibronectinas/metabolismo , Transição de Fase/efeitos dos fármacos , Polivinil/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fibroblastos/ultraestrutura , Camundongos , Microscopia de Força Atômica , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Água/química , Difração de Raios X
14.
Singapore Med J ; 53(2): 109-15, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22337185

RESUMO

INTRODUCTION: Patients in Singapore can choose their primary care provider on a per-episode basis and pay out-of-pocket for services rendered. The infrastructure of subsidised and private primary care sector facilities differs. Onsite ancillary services are available in subsidised facilities, allowing for convenience of routine investigations, while private clinics are usually standalone practices. This study sought to examine the factors influencing patients' choice of polyclinic. METHODS: This was a cross-sectional survey of a convenient sample of 484 random patients who sought treatment at a polyclinic located in a new housing estate from 24-27 June 2008. RESULTS: The response rate was 85.4% (n = 409). 38.1% of the patients were male. Mean age was 36.2 years. Only 13.8% had a regular private family physician, while 37.3% were followed up at polyclinics. Patients on regular polyclinic follow-up were more likely to be older (p < 0.001), unemployed, retirees or housewives (p < 0.001) and were seeking treatment for chronic diseases (p < 0.001). Geographical convenience (p = 0.002), low cost of consultation (p = 0.024), and onsite laboratory (p = 0.001) and imaging services (p = 0.018) significantly influenced those on regular polyclinic follow-up to attend the polyclinic. CONCLUSION: Affordability, convenience of travel and onsite laboratory facilities influence patients' choice of seeking treatment at polyclinics. Further research examining whether the overall convenience of onsite ancillary services influences patients' choice of primary care provider would be useful in redesigning private primary care infrastructure to enhance patient convenience and encourage more patients to have a regular private family physician.


Assuntos
Aceitação pelo Paciente de Cuidados de Saúde , Adulto , Comportamento de Escolha , Estudos Transversais , Feminino , Custos de Cuidados de Saúde/estatística & dados numéricos , Serviços de Saúde/estatística & dados numéricos , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Atenção Primária à Saúde/estatística & dados numéricos , Singapura , Fatores Socioeconômicos , Adulto Jovem
15.
Br J Radiol ; 84(1001): e91-4, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21511744

RESUMO

A 13-month-old male presented with large hepatic mass that was confirmed diagnostically to be a cystic hepatic mesenchymal hamartoma. The sieve-like appearance of the solid components of the mass, as seen at ultrasonography, and findings of dynamic post-contrast MRI are highlighted here. Beyond diagnostic imaging, we extended our role in patient management through ultrasound-guided intra-operative aspiration of fluid from the cystic components of the tumour to reduce its volume and thereby facilitate surgical resection.


Assuntos
Cistos/diagnóstico , Hamartoma/diagnóstico , Hepatopatias/diagnóstico , Imageamento por Ressonância Magnética/métodos , Ultrassonografia Doppler em Cores/métodos , Biópsia por Agulha , Cistos/diagnóstico por imagem , Hamartoma/diagnóstico por imagem , Humanos , Lactente , Hepatopatias/diagnóstico por imagem , Masculino
16.
J Biomater Sci Polym Ed ; 22(12): 1651-67, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20699059

RESUMO

α-Phase poly(vinylidene fluoride) (PVDF) has chains of zero dipole moments and is, therefore, nonpiezoelectric, while ß-phase PVDF has the most significant piezoelectric properties among the polymorphs due to its polar chains. Although many reports describe PVDF as a suitable biomaterial due to its stability and biocompatibility, few considered the specific effects that the different polymorphs exert on cellular behaviour. We hypothesized that α- and ß-phase PVDF will exert direct but different influences on cell attachment and metabolic activity. PVDF films were fabricated using N,N-dimethylformamide (DMF) and hexamethylphosphoramide (HMPA) by solvent casting. Samples were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy and X-ray diffraction. Films containing 83.5% α-phase PVDF (DMF-PVDFα) and 91.4% of ß-phase PVDF (HMPA-PVDFß within the crystalline regions were produced and used to evaluate in vitro attachment and metabolic activity of L929 cells. Cell metabolic activity on both PVDF conformations increased 3-fold over the 1-week culture period, with higher cell metabolic activity observed on DMF-PVDFα on day 5 of culture, compared to HMPA-PVDFß. Cells grown on DMF-PVDFα were well-spread, flat and expressed spotted paxillin in focal adhesions that were mainly localized to perinuclear regions of the cells, while a high proportion of cells on HMPA-PVDFß were bulging, round and expressed relatively fewer paxillin spots. Our results suggest that α-phase PVDF supports higher cell metabolic activity and better cell spreading compared to ß-phase PVDF. Such variations can potentially be exploited for different biomedical applications.


Assuntos
Fenômenos Fisiológicos Celulares/efeitos dos fármacos , Polivinil/química , Polivinil/farmacologia , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Varredura Diferencial de Calorimetria , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Forma Celular/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas , Isomerismo , Camundongos , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
17.
Diabetologia ; 53(4): 757-67, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20076942

RESUMO

AIMS/HYPOTHESIS: Insulin resistance (IR) is associated with obesity, but can also develop in individuals with normal body weight. We employed comprehensive profiling methods to identify metabolic events associated with IR, while controlling for obesity. METHODS: We selected 263 non-obese (BMI approximately 24 kg/m2) Asian-Indian and Chinese men from a large cross-sectional study carried out in Singapore. Individuals taking medication for diabetes or hyperlipidaemia were excluded. Participants were separated into lower and upper tertiles of IR based on HOMA indices of < or =1.06 or > or =1.93, respectively. MS-based metabolic profiling of acylcarnitines, amino acids and organic acids was combined with hormonal and cytokine profiling in all participants. RESULTS: After controlling for BMI, commonly accepted risk factors for IR, including circulating fatty acids and inflammatory cytokines, did not discriminate the upper and lower quartiles of insulin sensitivity in either Asian- Indian or Chinese men. Instead, IR was correlated with increased levels of alanine, proline, valine, leucine/isoleucine, phenylalanine, tyrosine, glutamate/glutamine and ornithine, and a cluster of branched-chain and related amino acids identified by principal components analysis. These changes were not due to increased protein intake by individuals in the upper quartile of IR. Increased abdominal adiposity and leptin, and decreased adiponectin and IGF-binding protein 1 were also correlated with IR. CONCLUSIONS/INTERPRETATION: These findings demonstrate that perturbations in amino acid homeostasis, but not inflammatory markers or NEFAs, are associated with IR in individuals of relatively low body mass.


Assuntos
Índice de Massa Corporal , Resistência à Insulina/fisiologia , Adiponectina/sangue , Adulto , Aminoácidos/sangue , Aminoácidos/metabolismo , Povo Asiático , Glicemia/metabolismo , Colesterol/sangue , Estudos Transversais , Demografia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/sangue , Humanos , Índia , Insulina/sangue , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/sangue , Interleucinas/sangue , Estilo de Vida , Lipídeos/sangue , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Seleção de Pacientes , Grupos Raciais , Fatores de Risco , Singapura/epidemiologia , População Branca
18.
Int J Obes (Lond) ; 33(11): 1299-308, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19736555

RESUMO

OBJECTIVE: To examine the changes in weight and waist circumference of adult Singaporeans between 1998 and 2005-2007, and the associations of these changes with demographic and socio-economic factors. METHODOLOGY: A prospective study, which followed up participants aged 18-69 years from the 1998 National Health Survey. Analysis was performed on data from 2483 individuals (53% of original sample) who returned for follow-up in 2005-2007. Body weight and waist circumference were measured both at baseline and follow-up. Logistic regression was used to examine factors associated with being overweight and obese at baseline. Linear regression was used to examine changes in weight and waist circumference over time. The variables examined were age, gender, ethnicity, marital status, educational level, housing and employment status, smoking, alcohol consumption and sports activities. RESULTS: Mean weight for the population increased over the follow-up period by 1.48 kg (s.d.=4.95) and mean waist circumference increased by 3.32 cm (s.d.=7.92). Cross-sectionally, those who were overweight or obese were more likely to be Malays or Indians, married, homemakers and have lower educational level. Prospectively, individuals who gained the most weight were younger, more likely to be ethnic minority groups and have the lowest body mass index (BMI) at baseline. They also appeared to be of higher socio-economic status (SES) based on housing type. These associations were statistically significant even after adjusting for other variables. CONCLUSION: Obesity prevention should start early in the younger age. Preventive programs need to reach out to Malay and Indian ethnic groups and those with higher SES. These findings should be used in designing messaging of preventive strategies.


Assuntos
Povo Asiático/etnologia , Peso Corporal/fisiologia , Obesidade/epidemiologia , Circunferência da Cintura/fisiologia , Adolescente , Adulto , Idoso , Índice de Massa Corporal , Peso Corporal/etnologia , Demografia , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Obesidade/etnologia , Estudos Prospectivos , Singapura/epidemiologia , Circunferência da Cintura/etnologia , Adulto Jovem
20.
Br J Cancer ; 100(8): 1358-64, 2009 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-19319135

RESUMO

We investigated common genetic variation in the entire ESR1 and EGF genes in relation to endometrial cancer risk, myometrial invasion and endometrial cancer survival. We genotyped a dense set of single-nucleotide polymorphisms (SNPs) in both genes and selected haplotype tagging SNPs (tagSNPs). The tagSNPs were genotyped in 713 Swedish endometrial cancer cases and 1567 population controls and the results incorporated into logistic regression and Cox proportional hazards models. We found five adjacent tagSNPs covering a region of 15 kb at the 5' end of ESR1 that decreased the endometrial cancer risk. The ESR1 variants did not, however, seem to affect myometrial invasion or endometrial cancer survival. For the EGF gene, no association emerged between common genetic variants and endometrial cancer risk or myometrial invasion, but we found a five-tagSNP region that covered 51 kb at the 5' end of the gene where all five tagSNPs seemed to decrease the risk of dying from endometrial cancer. One of the five tagSNPs in this region was in strong linkage disequilibrium (LD) with the untranslated A61G (rs4444903) EGF variant, earlier shown to be associated with risk for other forms of cancer.


Assuntos
Neoplasias do Endométrio/genética , Fator de Crescimento Epidérmico/genética , Receptor alfa de Estrogênio/genética , Variação Genética , Polimorfismo de Nucleotídeo Único , Idoso , Estudos de Casos e Controles , Neoplasias do Endométrio/epidemiologia , Neoplasias do Endométrio/mortalidade , Feminino , Genótipo , Humanos , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Sistema de Registros , Fatores de Risco , Análise de Sobrevida , Suécia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...