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1.
ACS Appl Mater Interfaces ; 15(1): 806-817, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36542810

RESUMO

Identifying thermodynamically favorable and stable non-stoichiometric metal oxides is of crucial importance for solar thermochemical (STC) fuel production via two-step redox cycles. The performance of a non-stoichiometric metal oxide depends on its thermodynamic properties, oxygen exchange capacity, and its phase stability under high-temperature redox cycling conditions. Perovskite oxides (ABO3-δ) are being considered as attractive alternatives to the state-of-the-art ceria (CeO2-δ) due to their high thermodynamic and structural tunability. However, perovskite oxides often exhibit low entropy change compared to ceria, as they generally have one only redox active site, leading to lower mass-specific fuel yields. Herein, we investigate cation-deficient Ce-substituted perovskite oxides as a new class of potential redox materials combining the advantages of perovskites and ceria. We newly synthesized the (CexSr1-x)0.95Ti0.5Mn0.5O3-δ (x = 0, 0.10, 0.15, and 0.20; CSTM) series, with dual-redox active sites comprising Ce (at the A-site) and Mn (at the B-site). By introducing a cation deficiency (∼5%), CSTM perovskite oxides with both phase purity (x ≤ 0.15) and high-temperature structural stability under STC redox cycling conditions are obtained. Thermodynamic properties are evaluated by measuring oxygen non-stoichiometry in the temperature range T = 700-1400 °C and the oxygen partial pressure range pO2 = 1-10-4 bar. The results demonstrate that CSTM perovskite oxides exhibit a composition-dependent simultaneous increase of enthalpy and entropy change with increasing Ce-substitution. (Ce0.20Sr0.80)0.95Ti0.5Mn0.5O3-δ (CSTM20) showed a combination of large entropy change of ∼141 J (mol-O)-1 K-1 and moderate enthalpy change of ∼238 kJ (mol-O)-1, thereby creating favorable conditions for thermochemical H2O splitting. Furthermore, the oxidation states and local coordination environment around Mn, Ce, and Ti sites in the pristine and reduced CSTM samples were extensively studied using X-ray absorption spectroscopy. The results confirmed that both Ce (at the A-site) and Mn (at the B-site) centers undergo simultaneous reduction during thermochemical redox cycling.

2.
Br J Surg ; 108(3): 315-325, 2021 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-33760065

RESUMO

BACKGROUND: Primary endocrine therapy may be an alternative treatment for less fit women with oestrogen receptor (ER)-positive breast cancer. This study compared quality-of-life (QoL) outcomes in older women treated with surgery or primary endocrine therapy. METHODS: This was a multicentre, prospective, observational cohort study of surgery or primary endocrine therapy in women aged over 70 years with operable breast cancer. QoL was assessed using European Organisation for Research and Treatment of cancer QoL questionnaires QLQ-C30, -BR23, and -ELD14, and the EuroQol Five Dimensions 5L score at baseline, 6 weeks, and 6, 12, 18, and 24 months. Propensity score matching was used to adjust for baseline variation in health, fitness, and tumour stage. RESULTS: The study recruited 3416 women (median age 77 (range 69-102) years) from 56 breast units. Of these, 2979 (87.2 per cent) had ER-positive breast cancer; 2354 women had surgery and 500 received primary endocrine therapy (125 were excluded from analysis due to inadequate data or non-standard therapy). Median follow-up was 52 months. The primary endocrine therapy group was older and less fit. Baseline QoL differed between the groups; the mean(s.d.) QLQ-C30 global health status score was 66.2(21.1) in patients who received primary endocrine therapy versus 77.1(17.8) among those who had surgery plus endocrine therapy. In the unmatched analysis, changes in QoL between 6 weeks and baseline were noted in several domains, but by 24 months most scores had returned to baseline levels. In the matched analysis, major surgery (mastectomy or axillary clearance) had a more pronounced adverse impact than primary endocrine therapy in several domains. CONCLUSION: Adverse effects on QoL are seen in the first few months after surgery, but by 24 months these have largely resolved. Women considering surgery should be informed of these effects.


Assuntos
Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/terapia , Qualidade de Vida , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/metabolismo , Neoplasias da Mama/psicologia , Feminino , Humanos , Estudos Longitudinais , Mastectomia , Estudos Prospectivos , Receptores de Estrogênio/metabolismo
3.
Br J Surg ; 108(5): 499-510, 2021 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-33760077

RESUMO

BACKGROUND: Rates of surgery and adjuvant therapy for breast cancer vary widely between breast units. This may contribute to differences in survival. This cluster RCT evaluated the impact of decision support interventions (DESIs) for older women with breast cancer, to ascertain whether DESIs influenced quality of life, survival, decision quality, and treatment choice. METHODS: A multicentre cluster RCT compared the use of two DESIs against usual care in treatment decision-making in older women (aged at least ≥70 years) with breast cancer. Each DESI comprised an online algorithm, booklet, and brief decision aid to inform choices between surgery plus adjuvant endocrine therapy versus primary endocrine therapy, and adjuvant chemotherapy versus no chemotherapy. The primary outcome was quality of life. Secondary outcomes included decision quality measures, survival, and treatment choice. RESULTS: A total of 46 breast units were randomized (21 intervention, 25 usual care), recruiting 1339 women (670 intervention, 669 usual care). There was no significant difference in global quality of life at 6 months after the baseline assessment on intention-to-treat analysis (difference -0.20, 95 per cent confidence interval (C.I.) -2.69 to 2.29; P = 0.900). In women offered a choice of primary endocrine therapy versus surgery plus endocrine therapy, knowledge about treatments was greater in the intervention arm (94 versus 74 per cent; P = 0.003). Treatment choice was altered, with a primary endocrine therapy rate among women with oestrogen receptor-positive disease of 21.0 per cent in the intervention versus 15.4 per cent in usual-care sites (difference 5.5 (95 per cent C.I. 1.1 to 10.0) per cent; P = 0.029). The chemotherapy rate was 10.3 per cent at intervention versus 14.8 per cent at usual-care sites (difference -4.5 (C.I. -8.0 to 0) per cent; P = 0.013). Survival was similar in both arms. CONCLUSION: The use of DESIs in older women increases knowledge of breast cancer treatment options, facilitates shared decision-making, and alters treatment selection. Trial registration numbers: EudraCT 2015-004220-61 (https://eudract.ema.europa.eu/), ISRCTN46099296 (http://www.controlled-trials.com).


Assuntos
Neoplasias da Mama/terapia , Tomada de Decisões , Técnicas de Apoio para a Decisão , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/mortalidade , Quimioterapia Adjuvante , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Qualidade de Vida
4.
Phys Chem Chem Phys ; 22(4): 2466-2474, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31939962

RESUMO

The perovskite oxide SrFeO3 has favourable redox properties for oxygen exchange applications, including oxygen separation and oxygen production chemical looping cycles. For such applications, lower temperature operation can improve the energy demand and feasibility of the process, but can also lead to kinetic limitations. Here we investigate the oxidation and reduction reaction kinetics of SrFeO3 in the temperature range 450-750 K. Isothermal relaxation techniques are used to observe the reaction rates across this temperature range, using a thermogravimetric analysis system. Experimental data are analysed according to an isoconversional method and fit with a simple power law model to extract activation energies. The apparent activation energy of oxidation and reduction was found to be 92 ± 16 and 144 ± 17 kJ mol-1 respectively. Comparison of oxidation and reduction kinetics together with considerations of particle size indicate that the oxidation reaction rate may be limited by diffusion in the bulk, while the reduction reaction rate is limited by the surface reaction. Furthermore, we also investigated the mixed perovskite Sr0.93Ca0.07Fe0.9Co0.1O3, which exhibited a 4-fold increase in the oxidation rate.

5.
Support Care Cancer ; 27(7): 2699-2705, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30488222

RESUMO

PURPOSE: Chemotherapy-induced nausea and vomiting (CINV) remain significant clinical problems, especially in the delayed phase (24-120 h after chemotherapy). Amisulpride is a dopamine D2/D3-receptor antagonist previously shown to be an effective intravenous antiemetic. We conducted a randomised, double-blind study to characterise the dose response of oral amisulpride in delayed phase CINV. METHODS: Chemotherapy-naïve patients receiving cisplatin ≥ 70 mg/m2 or an anthracycline-cyclophosphamide regimen for breast cancer received, on day 1, 20 mg amisulpride and 8-16 mg ondansetron intravenously followed, once daily on days 2-4, by 10, 20 or 40 mg oral amisulpride or placebo. A control group receiving standard three-drug prophylaxis was enrolled for assay sensitivity purposes. The primary endpoint was complete response (CR), defined as no emesis or rescue medication use, in the delayed phase. RESULTS: Three hundred eighteen subjects were evaluable per protocol. CR rate (24-120 h) was 20% with placebo and 46% with 10 mg amisulpride (p = 0.006 after multiplicity adjustment); in the three-drug control group, it was 59%. Emesis, nausea and 0-120-h CR rate were significantly improved with 10 mg amisulpride compared to placebo. Higher doses of amisulpride were not more effective than 10 mg. In patients with acute phase CR, delayed phase CR rate was 44% for placebo, 75% for 10 mg amisulpride (p = 0.022) and 70% for the 3-drug control. No significant differences were seen between groups in safety parameters. CONCLUSIONS: Amisulpride 10 mg orally is safe and superior to placebo at preventing delayed CINV caused by highly emetogenic chemotherapy. TRIAL REGISTRATION: NCT01857232.


Assuntos
Amissulprida/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Cisplatino/efeitos adversos , Náusea/prevenção & controle , Neoplasias/tratamento farmacológico , Vômito/prevenção & controle , Adulto , Idoso , Antraciclinas/efeitos adversos , Antieméticos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Cisplatino/uso terapêutico , Ciclofosfamida/efeitos adversos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Quimioterapia de Indução , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Ondansetron/uso terapêutico , Indução de Remissão , Vômito/induzido quimicamente
6.
J Res Med Sci ; 18(4): 341-5, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24124435

RESUMO

Nutrition for under-5 children is of great importance as the foundation for life-time health, strength, and intellectual vitality is laid during this period. Globally, more than one-third of the child deaths are attributable to under-nutrition. The discriminatory attitudes against female children vary from being implicit to those that are quite explicit. So, the present cross-sectional study aims to assess the nutritional status (gender differences) of 146 under-5 children attending Anganwadis and also to study the bio-socio-demographic factors associated with malnutrition attending three Anganwadis of Adopted Urban slum area, involving anthropometric examination using standardized techniques and interview using predesigned semi-structured questionnaire for the mothers in September-October 2011. Nutritional status grading was done based on weight for age as per Indian Academy of Pediatrics (IAP) Classification and using height for age as per Vishveshwara Rao's Classification. 51.4% were males, majority in age group of 2-3 years. 63% children were malnourished, majority in Grade I malnutrition. Out of the total females, 72% were stunted and 43% were severely malnourished having mid arm circumference <12.5 cm. Birth order (P < 0.05), education status of the mother (P < 0.001), socio-economic status (P < 0.05) and type of family (P < 0.05) were found to be significantly associated with malnutrition.

7.
J Laryngol Otol ; 127(1): 67-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23217274

RESUMO

OBJECTIVE: We present an extremely rare case of congenital cholesteatoma in identical twins. METHOD: Case report of congenital cholesteatoma in identical twins, and a literature review, are presented. RESULTS: Both cases presented to the ENT out-patient clinic, but with different clinical pictures. Both were managed surgically. CONCLUSION: Congenital cholesteatoma presents as a whitish mass in the middle ear, with an intact tympanic membrane. It is a rare entity comprising between 3.7 and 24 per cent of total cholesteatoma cases. The key to its diagnosis is the absence of previous ear infection, ear surgery and local trauma. To our best knowledge, this paper represents the first report in the world literature of congenital cholesteatoma in identical twins.


Assuntos
Colesteatoma/congênito , Doenças em Gêmeos , Processo Mastoide/cirurgia , Procedimentos Cirúrgicos Otológicos/métodos , Membrana Timpânica/patologia , Criança , Colesteatoma/diagnóstico , Colesteatoma/cirurgia , Diagnóstico Diferencial , Humanos , Masculino , Otoscopia , Tomografia Computadorizada por Raios X
8.
Ann R Coll Surg Engl ; 94(6): 411-5, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22943331

RESUMO

INTRODUCTION: Evidence suggests a clinical benefit with patch angioplasty after carotid endarterectomy (CEA). The UK National Vascular Database has demonstrated variation in practice but does not record technical details. This study was intended to define indications and technique of patching after CEA. METHODS: An electronic questionnaire was emailed to all 402 members of the Vascular Society of Great Britain and Ireland. The email could not be received by 23 and 14 did not perform CEA. Some questions allowed multiple answers. Fisher's exact test was used for statistical analysis. RESULTS: There were 187 responses (51%). Fifteen members (8%) performed eversion CEA, which obviates patching. Of all the respondents, 121 surgeons (65%) always use a patch. Seventy of these (58%) use the full patch width (median: 8 mm, range: 4-10 mm). Fourteen (12%) variably trimmed the patch (median: 7.5 mm, range: 5-10 mm) and 34 (28%) routinely trimmed (median: 6 mm, range: 3-20 mm). Selective patching, dependent on internal carotid artery diameter, was performed by 48 respondents (26%), 23 of whom specified a median artery threshold diameter of 5 mm (range: 3-8 mm). General anaesthesia was always or usually used by 83 surgeons (45%), local anaesthesia by 77 (41%) and the remainder followed patient choice. Obligatory patching is performed by 68 of the 83 respondents (82%) who prefer general anaesthesia whereas only 40 of the 77 surgeons (52%) who use local anaesthesia always patch (p<0.0001). CONCLUSIONS: There is a variable rate of patching after CEA in the UK, which appears dependent on the vessel size and mode of anaesthesia. There are also differences in the patch width adopted.


Assuntos
Angioplastia/métodos , Endarterectomia das Carótidas/métodos , Padrões de Prática Médica/estatística & dados numéricos , Anestesia Geral/estatística & dados numéricos , Anestesia Local/estatística & dados numéricos , Artéria Carótida Interna/cirurgia , Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas/estatística & dados numéricos , Humanos , Irlanda , Telas Cirúrgicas/estatística & dados numéricos , Inquéritos e Questionários , Técnicas de Sutura/estatística & dados numéricos , Reino Unido
12.
Gene Ther ; 15(8): 604-16, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18305577

RESUMO

Although adoptive T-cell therapy has shown clinical success, efficacy is limited by low levels of T-cell trafficking to, and survival in, the immunosuppressive environment of an established tumor. Oncolytic virotherapy has recently emerged as a promising approach to induce both direct tumor cell killing and local proinflammatory environments within tumors. However, inefficient systemic delivery of oncolytic viruses remains a barrier to use of these agents against metastatic disease that is not directly accessible to the end of a needle. Here we show that the ability of antigen-specific T cells to circulate freely, and to localize to tumors, can be exploited to achieve the systemic delivery of replication-competent, oncolytic vesicular stomatitis virus (VSV). Thus, VSV loaded onto OT-I T cells, specific for the SIINFEKL epitope of the ovalbumin antigen, was efficiently delivered to established B16ova tumors in the lungs of fully immune-competent C57Bl/6 mice leading to significant increases in therapy compared to the use of virus, or T cells, alone. Although OT-I T-cell-mediated delivery of VSV led to viral replication within tumors and direct viral oncolysis, therapy was also dependent upon an intact host immune system. Moreover, VSV loading onto the T cells increased both T-cell activation in vitro and T-cell trafficking in vivo. The combination of adoptive T-cell transfer of antigen-specific T cells, along with oncolytic virotherapy, can, therefore, increase the therapeutic utility of both approaches through multiple mechanisms and should be of direct translational value.


Assuntos
Transferência Adotiva/métodos , Antígenos de Neoplasias/imunologia , Linfócitos do Interstício Tumoral/imunologia , Neoplasias/terapia , Terapia Viral Oncolítica/métodos , Vesiculovirus/genética , Animais , Movimento Celular , Terapia Combinada , Terapia Genética/métodos , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/terapia , Ativação Linfocitária , Linfócitos do Interstício Tumoral/virologia , Melanoma Experimental , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Metástase Neoplásica/terapia , Transplante de Neoplasias , Replicação Viral
13.
Eur J Vasc Endovasc Surg ; 35(4): 436-8, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18226566

RESUMO

To demonstrate the use of a commercially available branch stent graft system, designed to preserve the internal iliac artery (IIA) in common iliac artery (CIA) aneurysms (CIAA) in two patients, who had undergone previous abdominal aortic aneurysm (AAA) surgery.


Assuntos
Angioplastia/instrumentação , Implante de Prótese Vascular/instrumentação , Aneurisma Ilíaco/cirurgia , Stents , Idoso , Aneurisma da Aorta Abdominal/complicações , Aneurisma da Aorta Abdominal/cirurgia , Humanos , Aneurisma Ilíaco/complicações , Masculino
14.
J Surg Res ; 129(1): 52-6, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16087194

RESUMO

Intimal hyperplasia (IH) can occur after any vascular injury and results from smooth muscle cells (SMC) proliferation, migration, and invasion into the subintimal space. The purpose of this study was to investigate the effect of six different statins on the proliferation, migration, and invasion of human venous SMC. The statins were all used at their Cmax concentrations. SMCs were used to construct growth curves in the presence of 10% fetal calf serum or 10% fetal calf serum supplemented with the six statins. Migration and invasion experiments were performed using modified Boyden chambers. The invasion experiments were performed using Matrigel coated plates. We found that all of the statins significantly inhibited SMC proliferation compared to the platelet-derived growth factor control (ranging from fluvastatin 33% of control to pravastatin 72% of control, P = 0.03). SMC migration through uncoated polycarbonate membranes in presence of the six statins was significantly reduced (ranging from lovastatin 43% to pravastatin 57% of control, P = 0.006). All six statins also significantly reduced SMC invasion (ranging from fluvastatin 65% to simvastatin 87% of control, P = 0.002). We conclude that the inhibitory effect of statins on SMC proliferation, migration, and invasion is a class, rather than drug specific effect.


Assuntos
Divisão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Quimiotaxia/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Miócitos de Músculo Liso/efeitos dos fármacos , Atorvastatina , Ácidos Graxos Monoinsaturados/farmacologia , Fluvastatina , Ácidos Heptanoicos/farmacologia , Humanos , Indóis/farmacologia , Lovastatina/farmacologia , Miócitos de Músculo Liso/fisiologia , Pravastatina/farmacologia , Piridinas/farmacologia , Pirróis/farmacologia , Veia Safena , Sinvastatina/farmacologia
15.
Eur J Vasc Endovasc Surg ; 29(2): 177-81, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15649726

RESUMO

OBJECTIVE: Intimal hyperplasia (IH) threatens the patency of up to 35% of saphenous vein (SV) bypass grafts. In addition to reducing cholesterol levels, statins may modulate smooth muscle cell proliferation and migration. Statins inhibit matrix metalloproteinase (MMP) activity. We therefore investigated the effect of six statins on neointimal formation and MMP activity in human SV organ culture. STUDY DESIGN: Human SV specimens were cultured for 14 days in the presence of six different statins and subsequently processed for measurement of neointimal thickness and MMP activity. The drug concentrations chosen corresponded to the manufacturers' Cmax. RESULTS: The six statins all significantly reduced IH development (P = 0.004) in association with reduced expression of proMMP-2 and 9 (P = 0.03) and reduced activity of activated MMP-2 and 9 (P = 0.03). CONCLUSION: This study suggests that the potential benefit of statins in reducing IH is a class effect and not confined to specific statins. The reduction of IH produced by statins may in part be due to their inhibition of MMPs.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Veia Safena/patologia , Túnica Íntima/patologia , Colagenases/efeitos dos fármacos , Colagenases/metabolismo , Precursores Enzimáticos/efeitos dos fármacos , Precursores Enzimáticos/metabolismo , Oclusão de Enxerto Vascular/prevenção & controle , Humanos , Hiperplasia/prevenção & controle , Metaloproteinase 2 da Matriz/efeitos dos fármacos , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/efeitos dos fármacos , Metaloproteinase 9 da Matriz/metabolismo , Veia Safena/metabolismo , Técnicas de Cultura de Tecidos , Túnica Íntima/metabolismo
16.
Eur J Vasc Endovasc Surg ; 25(5): 462-8, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12713787

RESUMO

OBJECTIVES: accurate diagnosis is essential if patients with chronic leg ulceration are to receive optimal treatment. This prospective study describes the findings of a standardised assessment protocol and the initial management of a consecutive series of patients with chronic leg ulceration presenting to a single-visit leg ulcer assessment clinic. METHODS: between January 1993 and January 1999, a total of 555 patients (220 men and 335 women of median age 73, range 28-95 years) with 689 chronic leg ulcers were assessed. Full clinical assessment, ankle:brachial pressure index and lower limb venous duplex scan were performed according to a standardised protocol and diagnostic and management data were recorded prospectively on a computerised database. RESULTS: venous disease alone was responsible for 496 of 689 (72%) ulcers. Isolated superficial venous reflux (SVR) was identified in 52% of limbs and two-thirds of these had superficial venous surgery. Combined SVR and segmental deep venous reflux (DVR) was present in 13%, and full-length DVR was present in 33% of limbs. Nineteen (4%) limbs had deep venous stenosis or obstruction. Overall, superficial venous surgery was performed in 43% and compression bandages or hosiery alone were applied in 52% of limbs. Mixed arterio-venous ulceration was present in 100 (14.5%) limbs of which 56 had arterial revascularisation, 38 had superficial venous surgery and 23 had compression alone. Fifteen limbs with pure arterial ulceration had angioplasty (n=13) or simple dressings alone (n=2). Ulceration due to lymphoedema (n=17), mixed lymphoedema and venous reflux (n=11) and other causes (n=50) were managed by compression, dressings or skin grafting. CONCLUSIONS: a standardised protocol of clinical and duplex assessment can lead to a diagnosis in 97% of chronic leg ulcers. Duplex is essential to confirm or exclude potentially correctable venous disease and allow tailored surgical intervention for those patients who many benefit.


Assuntos
Úlcera da Perna/diagnóstico por imagem , Úlcera da Perna/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Assistência Ambulatorial , Distribuição de Qui-Quadrado , Doença Crônica , Feminino , Humanos , Úlcera da Perna/etiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento , Ultrassonografia Doppler Dupla
17.
Am J Physiol Lung Cell Mol Physiol ; 281(6): L1436-43, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11704540

RESUMO

Carbon monoxide (CO) has been proposed to attenuate the vasoconstrictor response to local hypoxia that contributes to pulmonary hypertension. However, the segmental response to CO, as well as its mechanism of action in the pulmonary circulation, has not been fully defined. To investigate the hemodynamic response to exogenous CO, lungs from male Sprague-Dawley rats were perfused with physiological saline solution. Measurements were made of pulmonary arterial, venous, and capillary pressures. Lungs were constricted with the thromboxane mimetic U-46619. To examine the vasodilatory response to CO, 500 microl of CO-equilibrated physiological saline solution or vehicle were injected into the arterial line. Additionally, CO and vehicle responses were examined in the presence of the soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 microM) or the larger conductance calcium-activated K(+) (BK(Ca)) channel blockers tetraethylammonium chloride (10 mM) and iberiotoxin (100 nM). CO administration decreased vascular resistance to a similar degree in both vascular segments. This vasodilatory response was completely abolished in lungs pretreated with ODQ. Furthermore, CO administration increased whole lung cGMP content, which was prevented by ODQ. Neither tetraethylammonium chloride nor iberiotoxin affected the CO response. We conclude that exogenous CO administration causes vasodilation in the pulmonary vasculature via a soluble guanylyl cyclase-dependent mechanism that does not likely involve activation of K(Ca) channels.


Assuntos
Monóxido de Carbono/farmacologia , Circulação Pulmonar/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacologia , Animais , GMP Cíclico/metabolismo , Dipiridamol/farmacologia , Inibidores Enzimáticos/farmacologia , Heme Oxigenase (Desciclizante)/metabolismo , Hipertensão Pulmonar/fisiopatologia , Técnicas In Vitro , Masculino , Músculo Liso Vascular/metabolismo , Oxidiazóis/farmacologia , Peptídeos/farmacologia , Inibidores de Fosfodiesterase/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Quinoxalinas/farmacologia , Ratos , Ratos Sprague-Dawley , Tetraetilamônio/farmacologia , Resistência Vascular/efeitos dos fármacos
18.
J Agric Food Chem ; 49(8): 3579-83, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11513631

RESUMO

At present, the commonly used HPLC method for the analysis of caffeine and theobromine contents in aqueous cocoa extracts employs direct application of the extracts on the column. This practice gradually reduces the efficiency of the column and shortens its life. Also, this method gives inflated values due to interfering substances and difficulty in achieving baseline resolution. In the improved method, the interfering cocoa pigments are effectively removed by passing the aqueous extract through a Sep-pak C(18) cartridge. Subsequent injection on a C(18) reverse-phase column employing acetonitrile and water (20:80) as the mobile phase reduces the analysis time without affecting either resolution of the peak or the accuracy of caffeine and theobromine determination or achieving baseline resolution. Therefore, this method is ideally suited for rapid routine analysis of cocoa and its products.


Assuntos
Cacau/química , Cafeína/análise , Cromatografia Líquida de Alta Pressão/métodos , Teobromina/análise , Sensibilidade e Especificidade , Fatores de Tempo
19.
J Appl Physiol (1985) ; 90(1): 172-8, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11133908

RESUMO

Attenuation of sympathetic vasoconstriction (sympatholysis) in working muscles during dynamic exercise is controversial. A potential mechanism is a reduction in alpha-adrenergic-receptor responsiveness. The purpose of this study was to examine alpha(1)- and alpha(2)-adrenergic-receptor-mediated vasoconstriction in resting and exercising skeletal muscle using intra-arterial infusions of selective agonists. Thirteen mongrel dogs were instrumented chronically with flow probes on the external iliac arteries of both hindlimbs and a catheter in one femoral artery. The selective alpha(1)-adrenergic agonist (phenylephrine) or the selective alpha(2)-adrenergic agonist (clonidine) was infused as a bolus into the femoral artery catheter at rest and during mild and heavy exercise. Intra-arterial infusions of phenylephrine elicited reductions in vascular conductance of 76 +/- 4, 71 +/- 5, and 31 +/- 2% at rest, 3 miles/h, and 6 miles/h and 10% grade, respectively. Intra-arterial clonidine reduced vascular conductance by 81 +/- 5, 49 +/- 4, and 14 +/- 2%, respectively. The response to intra-arterial infusion of clonidine was unaffected by surgical sympathetic denervation. Agonist infusion did not affect either systemic blood pressure, heart rate, or blood flow in the contralateral iliac artery. alpha(1)-Adrenergic-receptor responsiveness was attenuated during heavy exercise. In contrast, alpha(2)-adrenergic-receptor responsiveness was attenuated even at a mild exercise intensity. These results suggest that the mechanism of exercise sympatholysis may involve reductions in postsynaptic alpha-adrenergic-receptor responsiveness.


Assuntos
Artéria Femoral/fisiologia , Artéria Ilíaca/fisiologia , Atividade Motora/fisiologia , Músculo Esquelético/irrigação sanguínea , Receptores Adrenérgicos alfa/fisiologia , Agonistas alfa-Adrenérgicos/farmacologia , Animais , Clonidina/farmacologia , Cães , Artéria Femoral/efeitos dos fármacos , Hemodinâmica/fisiologia , Membro Posterior , Artéria Ilíaca/efeitos dos fármacos , Injeções Intra-Arteriais , Músculo Esquelético/inervação , Fenilefrina/farmacologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Simpatectomia
20.
Eur J Vasc Endovasc Surg ; 19(1): 62-4, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10706837

RESUMO

OBJECTIVE: as a result of a serious complication from compression bandaging in a patient with venous ulceration and deep-vein obstruction, a policy of incremental compression in such limbs has been developed. The purpose of this retrospective study is to review the outcome of this policy. DESIGN: limbs with deep-venous obstruction (stenosis or occlusion) were treated initially with 3-layer compression bandaging and reviewed 24 h later. If 3-layer bandaging was tolerated, it was re-applied for a further 48 h. If there were no problems, then 4-layer bandaging was applied and the patient reviewed at 24 and 72 h. If 4-layer bandaging could not be tolerated, the limb was returned to 3-layer bandaging. RESULTS: of 325 limbs seen in a venous-ulcer clinic, 22 (7%) had deep-vein obstruction. Fifteen (68%) limbs were able to tolerate 4-layer bandaging, five (23%) could tolerate 3-layer bandaging and two limbs (9%) could only tolerate class 2 compression hosiery. The overall 1-year healing rate was 55%. There were no serious complications from bandaging. CONCLUSIONS: a protocol of incremental compression bandaging is safe in ulcerated legs with deep-vein obstruction and produces healing in up to 55% of cases.


Assuntos
Bandagens , Úlcera Varicosa/terapia , Idoso , Feminino , Humanos , Masculino , Fatores de Tempo , Resultado do Tratamento , Úlcera Varicosa/etiologia , Insuficiência Venosa/complicações , Cicatrização
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