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1.
Hong Kong Med J ; 30(1): 10-15, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38327164

RESUMO

INTRODUCTION: Left ventricular thrombus (LVT) is associated with significant morbidity and mortality. Conventional treatment comprises warfarin-mediated anticoagulation; it is unclear whether non-vitamin K oral anticoagulants (NOACs) exhibit comparable efficacy and safety. Limited data are available for Asian patients. This study compared NOACs with warfarin in terms of clinical efficacy and safety for managing LVT. METHODS: Clinical and echocardiographic records were retrieved for all adult patients with echocardiography-confirmed LVT at a major regional centre in Hong Kong from January 2011 to January 2020. Discontinuation of anticoagulation by 1 year was recorded. Outcomes were compared between patients receiving NOACs and those receiving warfarin. Primary outcomes were cumulative mortality and net adverse clinical events (NACEs). Secondary outcomes were complete LVT resolution and percentage reduction in LVT size at 3 months. RESULTS: Forty-three patients were included; 28 received warfarin and 15 received NOACs, with follow-up periods (mean ± standard deviation) of 20 ± 12 months and 22 ± 9 months, respectively (P=0.522). Use of NOACs was associated with significantly lower NACE risk (hazard ratio [HR]=0.111, 95% confidence interval [CI]=0.012-0.994; P=0.049) and a tendency towards lower cumulative mortality (HR=0.184, 95% CI=0.032-1.059; P=0.058). There were no significant differences in secondary outcomes. Considering LVT resolution, discontinuation of anticoagulation by 1 year was not significantly associated with different outcomes. CONCLUSION: Non-vitamin K oral anticoagulants may be an efficacious and safe alternative to warfarin for LVT management. Future studies should explore the safety and efficacy of anticoagulation discontinuation by 1 year as an overall strategy.


Assuntos
Fibrilação Atrial , Acidente Vascular Cerebral , Trombose , Adulto , Humanos , Varfarina/efeitos adversos , Anticoagulantes/efeitos adversos , Vitamina K/uso terapêutico , Administração Oral , Fibrilação Atrial/tratamento farmacológico , Trombose/diagnóstico por imagem , Trombose/tratamento farmacológico , Trombose/induzido quimicamente , Resultado do Tratamento , Acidente Vascular Cerebral/tratamento farmacológico
2.
Clin Oncol (R Coll Radiol) ; 35(6): e376-e383, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37031076

RESUMO

AIMS: Gonadotropin-releasing hormone (GnRH) agonists and antagonists, critical medications for prostate cancer (PCa) treatment, may differ in cardiovascular safety. This prospective cohort study aimed to compare the long-term cardiovascular risks between GnRH agonists and antagonists. MATERIALS AND METHODS: Patients with PCa receiving GnRH agonists or antagonists during 2013-2021 in Hong Kong were identified. Patients with <6 months' prescriptions, who were switching between drugs, had missing baseline prostate-specific antigen level or had a prior stroke or myocardial infarction were excluded. Patients were followed up until September 2021. The primary outcome was major adverse cardiovascular events (MACE) as in the PRONOUNCE trial (MACEPRONOUNCE), i.e. a composite of all-cause mortality, stroke and myocardial infarction. The secondary outcome was MACECVM, i.e. a composite of cardiovascular mortality, stroke and myocardial infarction. Inverse probability treatment weighting was used to balance covariates between groups. The Log-rank test was used to compare the cumulative freedom from the primary outcome between groups. RESULTS: In total, 2479 patients were analysed (162 GnRH antagonist users and 2317 agonist users; median age 75.0 years, interquartile range 68.0-81.6 years). Inverse probability treatment weighting achieved good covariate balance between groups. Over a median follow-up duration of 3.0 years (interquartile range 1.7-5.0 years), 1115 patients (45.0%) had MACEPRONOUNCE and 344 (13.9%) had MACECVM. GnRH agonist users had lower risks of MACEPRONOUNCE (Log-rank P < 0.001) and MACECVM (Log-rank P = 0.027). However, no differences were observed within 1 year of follow-up (MACEPRONOUNCE: Log-rank P = 0.308; MACECVM: Log-rank P = 0.357). Among patients without cardiovascular risk factors at baseline, GnRH agonist users had lower risks of MACEPRONOUNCE (Log-rank P < 0.001) and MACECVM (Log-rank P = 0.001), whereas no differences were observed in those with such risk factor(s) (MACEPRONOUNCE: Log-rank P = 0.569; MACECVM: Log-rank P = 0.615). CONCLUSIONS: GnRH antagonists may be associated with higher long-term, but not short-term, cardiovascular risks than agonists in Asian patients with PCa, particularly in those without known cardiovascular risk factors.


Assuntos
Doenças Cardiovasculares , Infarto do Miocárdio , Neoplasias da Próstata , Acidente Vascular Cerebral , Masculino , Humanos , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/induzido quimicamente , Doenças Cardiovasculares/epidemiologia , Hormônio Liberador de Gonadotropina/uso terapêutico , Fatores de Risco , Estudos Prospectivos , Estudos de Coortes , Antagonistas de Androgênios/uso terapêutico , Infarto do Miocárdio/induzido quimicamente , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/tratamento farmacológico , Neoplasias da Próstata/terapia , Acidente Vascular Cerebral/induzido quimicamente , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/tratamento farmacológico , Fatores de Risco de Doenças Cardíacas
6.
Artigo em Inglês | MEDLINE | ID: mdl-34040647

RESUMO

INTRODUCTION: The Carica papaya L. leaf is gaining interest as a potential therapeutic agent for alleviating dengue- and non-dengue-associated thrombocytopaenia. In that regard, safety considerations are as important as efficacy potential. The safety evaluation of botanical products for human use is complicated by variable formulations, complex phytochemical composition, and extrinsic toxicants. This review aimed to systematically collate related safety clinical and preclinical data, as well as reports on herb-drug interactions of C. papaya leaf consumption. METHODS: A systematic search using predetermined keywords on electronic databases (MEDLINE, Cochrane Library Central, LILACS, and Web of Science) and grey literature was conducted. Relevant clinical and preclinical studies were identified, screened, and analysed to present an overall safety profile of C. papaya leaf consumption. RESULTS: A total of 41 articles were included (23 clinical, 5 ongoing trials, and 13 preclinical) for descriptive analysis on study characteristics, adverse reactions, toxicity findings, and herb-drug interactions, from which 13 randomised controlled and quasiexperimental trials were further assessed for risk of bias and reporting quality. Overall, C. papaya leaf consumption (in the form of juice and standardised aqueous extract) was well tolerated by adult humans for short durations (

8.
Hong Kong Med J ; 26(1): 44-55, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32051329

RESUMO

Echocardiography is a key evaluation tool for the diagnosis, prognosis, and guidance of interventional management of numerous cardiovascular conditions, including ischaemia, heart failure, and structural heart diseases. Recent technological advancements have also seen the exploration of artificial intelligence, intracardiac vortex imaging, and three-dimensional printing in echocardiography. With cardiovascular diseases increasing in prevalence worldwide, it is important for clinicians including general practitioners to have updated knowledge of appropriate use of echocardiography. As such, this article reviews the current literature and summarises the latest developments and the general clinical usage of echocardiography.


Assuntos
Doenças Cardiovasculares/diagnóstico por imagem , Ecocardiografia/métodos , Coração/diagnóstico por imagem , Atenção Primária à Saúde/métodos , Cardiologia , Doenças Cardiovasculares/fisiopatologia , Ecocardiografia Tridimensional/tendências , Coração/fisiopatologia , Humanos
9.
Ann Oncol ; 30(6): 977-982, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30912815

RESUMO

BACKGROUND: Early-stage nasopharyngeal carcinoma (NPC) evades detection when the primary tumor is hidden from view on endoscopic examination. Therefore, in a prospective study of subjects being screened for NPC using plasma Epstein-Barr virus (EBV) DNA, we conducted a study to investigate whether magnetic resonance imaging (MRI) could detect endoscopically occult NPC. PATIENTS AND METHODS: Participants with persistently positive EBV DNA underwent endoscopic examination and biopsy when suspicious for NPC, followed by MRI blinded to the endoscopic findings. Participants with a negative endoscopic examination and positive MRI were recalled for biopsy or surveillance. Diagnostic performance was assessed by calculating sensitivity, specificity and accuracy, based on the histologic confirmation of NPC in the initial study or in a follow-up period of at least two years. RESULTS: Endoscopic examination and MRI were performed on 275 participants, 34 had NPC, 2 had other cancers and 239 without cancer were followed-up for a median of 36 months (24-60 months). Sensitivity, specificity and accuracy were 76.5%, 97.5% and 94.9%, respectively, for endoscopic examination and 91.2%, 97.5% and 96.7%, respectively, for MRI. NPC was detected only by endoscopic examination in 1/34 (2.9%) participants (a participant with stage I disease), and only by MRI in 6/34 (17.6%) participants (stage I = 4, II = 1, III = 1), two of whom had stage I disease and follow-up showing slow growth on MRI but no change on endoscopic examination for 36 months. CONCLUSION: MRI has a complementary role to play in NPC detection and can enable the earlier detection of endoscopically occult NPC.


Assuntos
Infecções por Vírus Epstein-Barr/diagnóstico , Carcinoma Nasofaríngeo/diagnóstico , Neoplasias Nasofaríngeas/diagnóstico , Adulto , DNA Viral/sangue , DNA Viral/genética , Detecção Precoce de Câncer/métodos , Endoscopia/métodos , Infecções por Vírus Epstein-Barr/sangue , Infecções por Vírus Epstein-Barr/patologia , Infecções por Vírus Epstein-Barr/virologia , Seguimentos , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/isolamento & purificação , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo/diagnóstico por imagem , Carcinoma Nasofaríngeo/cirurgia , Carcinoma Nasofaríngeo/virologia , Neoplasias Nasofaríngeas/diagnóstico por imagem , Neoplasias Nasofaríngeas/cirurgia , Neoplasias Nasofaríngeas/virologia , Prognóstico , Estudos Prospectivos , Carga Viral
10.
QJM ; 111(3): 203-204, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29194521
11.
Oncogene ; 37(2): 160-173, 2018 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-28892046

RESUMO

Most anticancer therapies to date focus on druggable features of tumor epithelia. Despite the increasing repertoire of treatment options, patient responses remain varied. Moreover, tumor resistance and relapse remain persistent clinical challenges. These observations imply an incomplete understanding of tumor heterogeneity. The tumor microenvironment is a major determinant of disease progression and therapy outcome. Cancer-associated fibroblasts (CAFs) are the dominant cell type within the reactive stroma of tumors. They orchestrate paracrine pro-tumorigenic signaling with adjacent tumor cells, thus exacerbating the hallmarks of cancer and accelerating tumor malignancy. Although CAF-derived soluble factors have been investigated for tumor stroma-directed therapy, the underlying transcriptional programs that enable the oncogenic functions of CAFs remain poorly understood. Nuclear receptors (NRs), a large family of ligand-responsive transcription factors, are pharmacologically viable targets for the suppression of CAF-facilitated oncogenesis. In this study, we defined the expression profiles of NRs in CAFs from clinical cutaneous squamous cell carcinoma (SCC) biopsies. We further identified a cluster of driver NRs in CAFs as important modifiers of CAF function with profound influence on cancer cell invasiveness, proliferation, drug resistance, energy metabolism and oxidative stress status. Importantly, guided by the NR profile of CAFs, retinoic acid receptor ß and androgen receptor antagonists were identified for concurrent therapy with cisplatin, resulting in the inhibition of chemoresistance in recurred SCC:CAF xenografts. Our work demonstrates that treatments targeting both the tumor epithelia and the surrounding CAFs can extend the efficacy of conventional chemotherapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Fibroblastos Associados a Câncer/efeitos dos fármacos , Carcinoma de Células Escamosas/patologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Receptores Citoplasmáticos e Nucleares/antagonistas & inibidores , Neoplasias Cutâneas/patologia , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biópsia , Fibroblastos Associados a Câncer/patologia , Carcinogênese/efeitos dos fármacos , Carcinogênese/patologia , Carcinoma de Células Escamosas/tratamento farmacológico , Linhagem Celular Tumoral , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Terapia Combinada/métodos , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Camundongos , Cultura Primária de Células , Receptores Citoplasmáticos e Nucleares/metabolismo , Neoplasias Cutâneas/tratamento farmacológico , Resultado do Tratamento , Microambiente Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
12.
Oncogene ; 36(46): 6408-6419, 2017 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-28745316

RESUMO

Metastatic cancer cells acquire energy-intensive processes including increased invasiveness and chemoresistance. However, how the energy demand is met and the molecular drivers that coordinate an increase in cellular metabolic activity to drive epithelial-mesenchymal transition (EMT), the first step of metastasis, remain unclear. Using different in vitro and in vivo EMT models with clinical patient's samples, we showed that EMT is an energy-demanding process fueled by glucose metabolism-derived adenosine triphosphate (ATP). We identified angiopoietin-like 4 (ANGPTL4) as a key player that coordinates an increase in cellular energy flux crucial for EMT via an ANGPTL4/14-3-3γ signaling axis. This augmented cellular metabolic activity enhanced metastasis. ANGPTL4 knockdown suppresses an adenylate energy charge elevation, delaying EMT. Using an in vivo dual-inducible EMT model, we found that ANGPTL4 deficiency reduces cancer metastasis to the lung and liver. Unbiased kinase inhibitor screens and Ingenuity Pathway Analysis revealed that ANGPTL4 regulates the expression of 14-3-3γ adaptor protein via the phosphatidylinositol-3-kinase/AKT and mitogen-activated protein kinase signaling pathways that culminate to activation of transcription factors, CREB, cFOS and STAT3. Using a different mode of action, as compared with protein kinases, the ANGPTL4/14-3-3γ signaling axis consolidated cellular bioenergetics and stabilized critical EMT proteins to coordinate energy demand and enhanced EMT competency and metastasis, through interaction with specific phosphorylation signals on target proteins.


Assuntos
Proteínas 14-3-3/metabolismo , Proteína 4 Semelhante a Angiopoietina/metabolismo , Transição Epitelial-Mesenquimal , Transdução de Sinais , Proteínas 14-3-3/genética , Trifosfato de Adenosina/metabolismo , Proteína 4 Semelhante a Angiopoietina/genética , Animais , Linhagem Celular Tumoral , Células HEK293 , Células Hep G2 , Humanos , Immunoblotting , Células MCF-7 , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Microscopia Confocal , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Interferência de RNA , Fator de Transcrição STAT3/metabolismo , Transplante Heterólogo
13.
J Intellect Disabil Res ; 61(6): 532-548, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28387017

RESUMO

BACKGROUND: Recent literature has suggested that relaxation activities can reduce the challenging behaviours of people with intellectual disabilities, particularly in severe and profound grades, due to the counteractive effect of muscle relaxation on emotional frustration or psychological distress. Despite having inconclusive evidence, multisensory environment (MSE) and massage therapy (MT) are the commonly used approaches to relaxation among these people. However, these two approaches have not yet practised or tested in combination for reducing these people's challenging behaviours. METHODS: A preliminary clinical efficacy trial was conducted to evaluate the effects of MT, MSE and their combined use for residents with intellectual disabilities in a long-term care facility on reducing their challenging behaviours. Eligible residents were recruited and randomly assigned to one of the four study groups (n = 11-12 per group), that is, MT in MSE, MSE alone, MT alone or usual care, for a 10-week intervention after a 1-month washout period. Outcome measures, including the Behaviour Problem Inventory, pulse and respiration rates, Behaviour Checklist and Alertness Observation Checklist, were assessed at recruitment and immediately following the interventions. RESULTS: A total of 42 participants (17 men and 25 women) completed the study. There were no significant differences in frequency and severity of challenging behaviours and most of the outcome measures between the four groups at post-test. Nevertheless, there were statistical significant differences on the active and inactive state (Alertness Observation Checklist) between the three treatment and control groups. Many participants in the three treatment groups changed from an active to inactive state (i.e. reduced activity levels) throughout the interventions, especially the MT in MSE. Such inactivity might suggest the participants' brief exhaustion followed by a period of alertness during the treatment activities. But their attention span and social contact to the immediate environment could still be maintained. CONCLUSIONS: Participants of MT in multisensory environment acquired more inactive state than the other study groups. This inactive state indicates a state of 'passive alertness', which is more likely in a relaxing manner.


Assuntos
Deficiência Intelectual/reabilitação , Massagem/métodos , Avaliação de Resultados em Cuidados de Saúde , Comportamento Problema , Adulto , Feminino , Humanos , Deficiência Intelectual/fisiopatologia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Índice de Gravidade de Doença
14.
Am J Transplant ; 16(12): 3416-3429, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27172087

RESUMO

Pretransplant autoantibodies to LG3 and angiotensin II type 1 receptors (AT1R) are associated with acute rejection in kidney transplant recipients, whereas antivimentin autoantibodies participate in heart transplant rejection. Ischemia-reperfusion injury (IRI) can modify self-antigenic targets. We hypothesized that ischemia-reperfusion creates permissive conditions for autoantibodies to interact with their antigenic targets and leads to enhanced renal damage and dysfunction. In 172 kidney transplant recipients, we found that pretransplant anti-LG3 antibodies were associated with an increased risk of delayed graft function (DGF). Pretransplant anti-LG3 antibodies are inversely associated with graft function at 1 year after transplantation in patients who experienced DGF, independent of rejection. Pretransplant anti-AT1R and antivimentin were not associated with DGF or its functional outcome. In a model of renal IRI in mice, passive transfer of anti-LG3 IgG led to enhanced dysfunction and microvascular injury compared with passive transfer with control IgG. Passive transfer of anti-LG3 antibodies also favored intrarenal microvascular complement activation, microvascular rarefaction and fibrosis after IRI. Our results suggest that anti-LG3 antibodies are novel aggravating factors for renal IRI. These results provide novel insights into the pathways that modulate the severity of renal injury at the time of transplantation and their impact on long-term outcomes.


Assuntos
Autoanticorpos/sangue , Função Retardada do Enxerto/etiologia , Sobrevivência de Enxerto/imunologia , Proteoglicanas de Heparan Sulfato/imunologia , Transplante de Rim/efeitos adversos , Traumatismo por Reperfusão/etiologia , Animais , Autoanticorpos/imunologia , Função Retardada do Enxerto/sangue , Função Retardada do Enxerto/patologia , Feminino , Seguimentos , Taxa de Filtração Glomerular , Humanos , Falência Renal Crônica/cirurgia , Testes de Função Renal , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Prognóstico , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/patologia , Estudos Retrospectivos , Fatores de Risco
16.
J Cell Biochem ; 114(10): 2356-62, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23633411

RESUMO

We sought to determine whether the estrogen receptor-related receptor gamma (mEsrrg) regulated the Osteopontin (Opn) promoter through the same AP1/CAAT box element that we have previously described for mEsrra. In HeLa cells mEsrrg used an additional site present in the 5'UTR, while in ROS17/2.8 cells the AP1/CAAT site was not used, but a completely novel site surrounding the transcription start site was used. We also find that in ROS17/2.8 cells mEsrra repressed, while mEsrrg activated the Opn promoter. None of the sites identified conform to established Esrr response elements (ERREs). Additionally, the two reported mEsrrg protein isoforms showed differences in their activation potential. Mutations in the activation function 2 (AF2) of mEsrra, predicted to abolish activation, surprisingly turned mEsrra into a better activator. In contrast, similar AF2 mutations in Esrrg2 abolished its ability to activate the Opn promoter. Mutation of the DNA binding domain of mEsrra/g2 abolished transcriptional activity in HeLa and ROS17/2.8 cells. Our data indicate, first, that the two Esrr isoforms regulate Opn in a cell context-dependent manner. Second, they suggest that although the DNA binding domains of mEsrra and mEsrrg are 93% identical and required for regulation, the receptors bind to distinct Opn promoter elements, suggesting that the two isoforms may co-regulate Opn, and perhaps other genes, without competing for the same site in the promoter. Finally, the results suggest that each isoform interacts differently with co-activators and co-repressors, as highlighted by the AF2 mutation that turns mEsrra into a better activator but abolishes activity of Esrrg2.


Assuntos
Osteopontina/genética , Regiões Promotoras Genéticas/genética , Receptores de Estrogênio/metabolismo , Células HeLa , Humanos , Osteoblastos/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Receptores de Estrogênio/genética
17.
Diabetologia ; 56(7): 1649-60, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23609310

RESUMO

AIMS/HYPOTHESIS: We investigated whether heterogeneous nuclear ribonucleoproteins F and K (hnRNP F, hnRNP K) mediate insulin inhibition of renal Agt expression and prevention of hypertension and kidney injury in an Akita mouse model of type 1 diabetes. METHODS: Adult male Akita mice (12 weeks old) were treated with insulin implants and killed at week 16. Untreated non-Akita littermates served as controls. The effects of insulin on blood glucose, systolic BP (SBP), renal proximal tubular cell (RPTC) gene expression and interstitial fibrosis were studied. We also examined immortalised rat RPTCs stably transfected with control plasmid or with plasmid containing rat Agt promoter in vitro. RESULTS: Insulin treatment normalised blood glucose levels and SBP, inhibited renal AGT expression but enhanced hnRNP F, hnRNP K and angiotensin-converting enzyme-2 expression, attenuated renal hypertrophy and glomerular hyperfiltration and decreased urinary albumin/creatinine ratio, as well as AGT and angiotensin II levels, in Akita mice. In vitro, insulin inhibited Agt but stimulated Hnrnpf and Hnrnpk expression in high-glucose media via p44/42 mitogen-activated protein kinase signalling in RPTCs. Transfection with Hnrnpf or Hnrnpk small interfering RNAs prevented insulin inhibition of Agt expression in RPTCs. CONCLUSIONS/INTERPRETATION: These data indicate that insulin prevents hypertension and attenuates kidney injury, at least in part, through suppressing renal Agt transcription via upregulation of hnRNP F and hnRNP K expression in diabetic Akita mice. HnRNP F and hnRNP K may be potential targets in the treatment of hypertension and kidney injury in diabetes.


Assuntos
Angiotensinogênio/metabolismo , Hipertensão/prevenção & controle , Insulina/uso terapêutico , Rim/efeitos dos fármacos , Angiotensinogênio/genética , Animais , Glicemia/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Rim/patologia , Masculino , Camundongos
18.
Opt Express ; 19(13): 12434-9, 2011 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-21716482

RESUMO

A simple technique for transverse mode selection in a large-mode-area (multimode) fiber laser is described. The technique exploits the different spectral responses of feedback elements based on a fiber Bragg grating and a volume Bragg grating to achieve wavelength-dependent mode filtering. This approach has been applied to a cladding-pumped thulium-doped fiber laser with a multimode core to achieve a single-spatial-mode output beam with a beam propagation factor (M2) of 1.05 at 1923 nm. Without mode selection the free-running fiber laser has a multimode output beam with an M2 parameter of 3.3. Selective excitation of higher order modes is also possible via the technique and preliminary results for laser oscillation on the LP11 mode are also discussed along with the prospects for scaling to higher power levels.


Assuntos
Tecnologia de Fibra Óptica/instrumentação , Tecnologia de Fibra Óptica/métodos , Lasers , Fibras Ópticas , Túlio/química , Retroalimentação , Germânio/química , Modelos Teóricos
19.
Eur Neuropsychopharmacol ; 18(12): 908-16, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18789657

RESUMO

Current antidepressants have a delayed onset of action and disturbing side effects, including inhibition of sexual behavior. It is hypothesized that novel drugs, hitting multiple disease-relevant targets, may yield a new generation of superior antidepressants. One such approach is simultaneous inhibition of serotonin, norepinephrine and dopamine transporters. We tested the triple uptake inhibitor (TUI), DOV 216,303 (5, 10 and 20 mg/kg) after 1, 7 and 14 days administration in the olfactory bulbectomized (OBX) rat depression model, and in a model of rat sexual behavior to detect putative sexual side effects. Chronic, but not acute treatment of DOV 216,303 (20 mg/kg) normalized OBX-induced hyperactivity in the open field, similar to the effect of imipramine (20 mg/kg). None of the doses of DOV 216,303 had any effect on sexual behavior at any time point. The results indicate that DOV 216,303 displays antidepressant efficacy and is devoid of sexual side effects.


Assuntos
Antidepressivos/uso terapêutico , Compostos Aza/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Depressão/tratamento farmacológico , Ejaculação/efeitos dos fármacos , Bulbo Olfatório/cirurgia , Animais , Comportamento Animal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Comportamento Exploratório/efeitos dos fármacos , Masculino , Paroxetina/uso terapêutico , Ratos , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacos , Estatísticas não Paramétricas
20.
Vox Sang ; 93(1): 57-63, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17547566

RESUMO

BACKGROUND AND OBJECTIVES: Adequate blood supply is crucial to the health-care system. To maintain a stable donor pool, donation-promotion strategies should not only be targeted in recruitment but also focus on retaining donors to give blood regularly. A study using statistical modelling is conducted to understand the first 4-year donation patterns for drop-out and committed first-time blood donors and to build model for the donor-type identification based on their first 1.5-year donation patterns. SUBJECTS AND METHODS: First-time whole blood (n= 20 631) adult donors recruited in year 2000 and 2001 in Hong Kong were observed for more than 4 years. Cluster analysis was first applied to group donor type by their similarities in donation behaviour under the surveillance period. A decision tree model based on a shorter surveillance period (1.5 years) is then built to predict the donor type. RESULTS: Three donation patterns - one-time, drop-out, and committed donor behaviour - were identified in cluster analysis. Three variables - donation frequencies in the first-year and in the half-year period after first year, and the number of donation centre visits in the following half year after first year, were able to predict drop-out donors with potential to become committed and committed donors with relatively lower donation frequency. CONCLUSIONS: The present statistical modelling is able to identify those donors with potential to become committed donors and those committed donors who can donate more frequently. This information is useful for development of targeted donor retention strategies.


Assuntos
Doadores de Sangue/provisão & distribuição , Modelos Estatísticos , Adulto , Povo Asiático , Feminino , Previsões/métodos , Hong Kong , Humanos , Masculino , Valor Preditivo dos Testes
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