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2.
Ann Oncol ; 28(9): 2256-2263, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28633409

RESUMO

BACKGROUND: Immune checkpoint inhibitors improve outcomes compared with chemotherapy in lung cancer. Tumor PD-L1 receptor expression is being studied as a predictive biomarker. The objective of this study was to assess the cost-effectiveness and economic impact of second-line treatment with nivolumab, pembrolizumab, and atezolizumab with and without the use of PD-L1 testing for patient selection. DESIGN: We developed a decision-analytic model to determine the cost-effectiveness of PD-L1 assessment and second-line immunotherapy versus docetaxel. The model used outcomes data from randomized clinical trials (RCTs) and drug acquisition costs from the United States. Thereafter, we used epidemiologic data to estimate the economic impact of the treatment. RESULTS: We included four RCTs (2 with nivolumab, 1 with pembrolizumab, and 1 with atezolizumab). The incremental quality-adjusted life year (QALY) for nivolumab was 0.417 among squamous tumors and 0.287 among non-squamous tumors and the incremental cost-effectiveness ratio (ICER) were $155 605 and $187 685, respectively. The QALY gain in the base case for atezolizumab was 0.354 and the ICER was $215 802. Compared with treating all patients, the selection of patients by PD-L1 expression improved incremental QALY by up to 183% and decreased the ICER by up to 65%. Pembrolizumab was studied only in patients whose tumors expressed PD-L1. The QALY gain was 0.346 and the ICER was $98 421. Patient selection also reduced the budget impact of immunotherapy. CONCLUSION: The use of PD-L1 expression as a biomarker increases cost-effectiveness of immunotherapy but also diminishes the number of potential life-years saved.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Antígeno B7-H1/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Análise Custo-Benefício , Imunoterapia/métodos , Neoplasias Pulmonares/tratamento farmacológico , Antineoplásicos Imunológicos/economia , Orçamentos , Carcinoma Pulmonar de Células não Pequenas/fisiopatologia , Custos de Medicamentos , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/fisiopatologia , Anos de Vida Ajustados por Qualidade de Vida , Análise de Sobrevida , Resultado do Tratamento
3.
Opt Express ; 21(6): 6889-94, 2013 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-23546071

RESUMO

n-channel body-tied partially depleted metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated for large current applications on a silicon-on-insulator wafer with photonics-oriented specifications. The MOSFET can drive an electrical current as large as 20 mA. We monolithically integrated this MOSFET with a 2 × 2 Mach-Zehnder interferometer optical switch having thermo-optic phase shifters. The static and dynamic performances of the integrated device are experimentally evaluated.


Assuntos
Interferometria/instrumentação , Refratometria/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação , Silício/química , Transistores Eletrônicos , Condutividade Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Temperatura Alta , Fótons , Integração de Sistemas
5.
Abdom Imaging ; 28(5): 694-9, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14628879

RESUMO

BACKGROUND: We assessed the usefulness of magnetic resonance imaging (MRI) in identifying nonmalignant intraductal papillary mucinous tumors (IPMTs) of the pancreas. METHODS: Thirty-three patients with branch duct-type IPMT diagnosed by endoscopic retrograde cholangiopancreatography were prospectively examined with magnetic resonance cholangiopancreatography followed by dynamic gadolinium-enhanced MRI examinations, and patients with no findings suggestive of malignancy, including a solid mass, mural nodules, a main pancreatic duct wider than 5 mm in diameter, and stenosis of the main pancreatic duct, were prospectively followed up with sequential MRI examinations once or twice a year. RESULTS: Twenty-six (79%) patients showed no findings suggestive of malignancy in the initial MRI examination. The diameter (mean +/- standard error) of the main pancreatic duct was 3.9 +/- 0.7 mm and that of the ectatic branch pancreatic duct was 36.0 +/- 9.1 mm. Twenty-three patients were prospectively followed for more than 36 months and 22 of them showed no findings suggestive of malignancy during follow-up periods ranging from 39 to 77 months (mean = 55 months). CONCLUSION: MRI was useful to identify nonmalignant IPMTs of the branch duct type, and close follow-up observation with serial MRI examinations may be appropriate in the management of such patients.


Assuntos
Adenocarcinoma Mucinoso/patologia , Adenocarcinoma Papilar/patologia , Carcinoma Ductal Pancreático/patologia , Imageamento por Ressonância Magnética , Neoplasias Pancreáticas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
6.
Environ Toxicol Chem ; 20(11): 2552-60, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11699782

RESUMO

We studied the chronic effects of 4-nonylphenol (4-NP) on reproductive status of medaka (Oryzias latipes) over two generations of continuous exposure. The exposure study of the parental (F0) medaka was begun on embryos within 24 h postfertilization and continued with monitoring through embryological development, hatching, posthatch survival, growth, sexual differentiation, and reproduction under flow-through exposures to mean measured 4-NP concentrations of 4.2, 8.2, 17.7, 51.5, and 183 microg/L for up to 104 d. Eggs spawned from the F0 fish at 102 and 103 d posthatch were also examined for hatchability, survival after hatching, growth, and sexual differentiation until 60 d posthatch. The 183-microg/L treatment significantly reduced the embryo survival and swim-up success of the F0 fish. The cumulative mortality after swim-up of the F0 fish exposed to 17.7 and 51.5 microg/L were significantly higher than the control mortality. No concentration-related effect of 4-NP was observed on the growth of surviving F0 fish at 60 d posthatch. However, the sex ratio estimated from the appearance of their secondary sex characteristics was skewed toward female in the 51.5-microg/L treatment. Additionally, gonadal histology showed that 20% of the fish in the 17.7-microg/L treatment and 40% in the 51.5-microg/L treatment had testis-ova, indicating that 4-NP affects the gonadal development and survival of medaka at similar concentrations in juveniles. The sex ratio of the F0 fish in the 51.5-microg/L treatment was completely skewed toward female; subsequently, the effects on fecundity and fertility in this generation were monitored at mean measured concentrations of 4.2, 8.2, and 17.7 microg/L from 71 to 103 d posthatch. Fecundity was unaffected by any of the treatments examined. The mean fertility in the 17.7-microg/L treatment was reduced to 76% of that in the controls, although no statistically significant differences were determined. Overall, these results indicate that the lowest-observed-effect concentration (LOEC) and no-observed-effect concentration (NOEC) of 4-NP through the life cycle of the F0 medaka were 17.7 and 8.2 microg/L, respectively. In the F1 medaka, no significant effects were observed on hatching success, posthatch mortality, or growth, but sexual differentiation at 60 d posthatch was affected. Induction of testis-ova in the gonads of the F1 fish was observed in both the 8.2- and the 17.7-microg/L concentrations. The results indicate that 4-NP can have significant effects on reproductive potential of medaka at concentrations as low as 17.7 microg/L.


Assuntos
Oryzias/fisiologia , Fenóis/toxicidade , Reprodução/efeitos dos fármacos , Diferenciação Sexual/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário , Feminino , Gônadas/efeitos dos fármacos , Gônadas/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Masculino , Razão de Masculinidade , Análise de Sobrevida , Natação
7.
No To Shinkei ; 53(6): 585-97, 2001 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-11441873

RESUMO

We report a 68-year-old man with progressive speech disturbance and dementia. He was well until 1995, when he noted an onset of difficulty in speech. He was able to name simple objects and understand language, however, he showed great difficulty in spontaneous speech. In 1998, he visited our service. He was alert and oriented, but he showed moderate degree of dementia. He did not appear to have aphasia but he showed marked dysarthria and slurred speech. He showed limb-kinetic apraxia in his right hand. He showed moderate restriction in his vertical gaze, masked face, and dysphagia. He walked normally. No rigidity, ataxia, or abnormal involuntary movement was noted. He showed grasp response and he was bradykinetic. He was treated with levodopa without effect. His condition deteriorated slowly and he was admitted to our service because of fever on February 13, 1999. He was alert but almost mute. He was unable to look upward or downward. Oculocephalic response was preserved. Axial rigidity was noted but no limb rigidity was present. He walked with small steps. Retropulsion was present. Deep tendon reflexes were diminished and the plantar response was flexor bilaterally. Laboratory examinations were unremarkable and his fever went down within a few days by supportive treatment. He was discharged to his home, where his condition deteriorated further. He developed cardiopulmonary arrest on May 3, 1999 and was brought into ER again. Cardiopulmonary resuscitation was unsuccessful and he was pronounced dead at 7:30 in the morning on the same day. The patient was discussed in a neurological CPC. The chief discussant arrived at the conclusion that this patient had corticobasal degeneration. But he felt that the differential diagnosis from atypical progressive supranuclear palsy, in which cortical pathology and symptoms predominated as in corticobasal degeneration, would be extremely difficult. Most of the participants felt that this patient had corticobasal degeneration, but a few thought that he had atypical PSP. Post-mortem examination revealed asymmetric cortical atrophy, which was accentuated in the left motor cortical area. Microscopic examination of the precentral cortex revealed neuronal loss and gliosis. Ballooned neurons and astrocytic plaques were also seen. The substantia nigra showed marked neuronal loss. Neuropil threads were observed in the nigra. Those threads were positive for anti-tau immunohistochemistry. The internal segment of the globus pallidus, the subthalamic nucleus, and the cerebellar dentate nucleus showed mild to moderate neuronal loss. A few neurofibrillary tangle-positive neurons were seen in these structures. Neuropil threads were also seen throughout. Pathologic changes were consistent with the diagnosis of corticobasal degeneration. One of the participants pointed out that he was able to walk at the time when he was showing marked speech disturbance and limb-kinetic apraxia, which was rather unusual for PSP suggesting corticobasal degeneration.


Assuntos
Doenças dos Gânglios da Base/complicações , Demência/etiologia , Hipocinesia/etiologia , Distúrbios da Fala/etiologia , Idoso , Doenças dos Gânglios da Base/patologia , Encéfalo/patologia , Córtex Cerebelar/patologia , Diagnóstico Diferencial , Humanos , Masculino , Paralisia Supranuclear Progressiva/diagnóstico
8.
J Nucl Med ; 41(4): 763-9, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10768580

RESUMO

UNLABELLED: The purpose of this study was to evaluate the kinetics and image quality of positron-emitting 38K (half-life, 7.6 min) and high-resolution small-animal PET in the heart, kidney, and brain of rabbits. METHODS: Studies were performed with 18 closed-chest anesthetized rabbits at baseline and during infusions of adenosine (0.2 mg/kg/min) and propranolol (0.5-1.0 mg/kg intravenously) using high-resolution small-animal PET. 38K was injected intravenously and dynamic PET imaging of the heart, kidney, or brain was performed for 3 min. Colored microspheres were injected into the left ventricle to measure organ blood flow. Arterial blood was withdrawn directly from the femoral artery, and, after the animals were killed, 38K activities in each organ were measured directly with a well counter. Uptake of 38K was calculated by dividing the 38K activities in each organ by the integral of the input function. The extraction fraction of 38K was estimated by dividing the uptake of 38K in each organ by the organ blood flow, measured by microspheres. RESULTS: The left ventricular myocardium and kidney were clearly visualized, but there was no visual 38K uptake in the brain. For the heart, kidney, and brain, respectively, average blood flow was 2.91 +/- 1.29, 5.49 +/- 0.71, and 0.57 +/- 0.11 mL/min/g, and the extraction fraction of 38K at baseline was 0.55 +/- 0.13, 0.48 +/- 0.13, and 0.022 +/- 0004. The Renkin-Crone model fit the relation between myocardial extraction and flow under a wide range of myocardial blood flow (r = 0.89). CONCLUSION: 38K is a suitable tracer for noninvasively showing the potassium kinetics of the heart, kidney, and brain by PET imaging.


Assuntos
Encéfalo/diagnóstico por imagem , Coração/diagnóstico por imagem , Rim/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Radioisótopos de Potássio , Animais , Masculino , Radioisótopos de Potássio/farmacocinética , Coelhos
9.
Jpn Circ J ; 64(12): 971-6, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11194293

RESUMO

The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg x kg(-1) x min(-1)) in 8 WHHL rabbits (13.8+/-0.5 months) with 13N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml x min(-1) x g(-1)) did not differ significantly between control and WHHL groups both at baseline (3.67+/-0.72 vs 4.26+/-1.12 ml x min(-1) x g(-1), p=NS) and with adenosine (7.92+/-2.00 vs 9.27+/-2.91 ml x min(-1) x g(-1), p=NS), nor did coronary flow reserve (2.16+/-0.37 vs 2.18+/-0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model.


Assuntos
Adenosina/farmacologia , Circulação Coronária/efeitos dos fármacos , Hiperlipidemias/fisiopatologia , Coelhos/fisiologia , Animais , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/patologia , Doença da Artéria Coronariana/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Hiperlipidemias/diagnóstico por imagem , Hiperlipidemias/patologia , Masculino , Microesferas , Modelos Animais , Coelhos/sangue , Tomografia Computadorizada de Emissão
10.
Jpn Circ J ; 63(10): 789-93, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10553922

RESUMO

The authors recently developed a cone-beam computed tomography (CT) scanner and this report presents their evaluation of its potential for thoracic vascular imaging. An X-ray tube and a video-fluoroscopic system were rotated around the objects and 360 projected images were collected in a 12-s scan. Each image was digitized and a 3 dimensional (D) image (256x256x256 voxel volume with a voxel dimension of 0.9x0.9x0.9 mm) was reconstructed. Two different 3D-CT angiographies were investigated in 2 pigs: right atriography and thoracic aortography. Each pig was anesthetized, mechanically ventilated and positioned within the scanner. Contrast agent was infused through the right atrium or the aortic root at a rate of 3 ml/s during the scan. The right atriography scan clearly delineated the anatomy of the pulmonary artery, heart chambers and thoracic aorta. The thoracic aortography scan also clearly delineated the aortic anatomy including the internal thoracic and intercostal arteries. In conclusion, cone-beam CT angiography is potentially useful for thoracic vascular imaging.


Assuntos
Angiografia/métodos , Processamento de Imagem Assistida por Computador , Radiografia Torácica/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Suínos , Artérias Torácicas/diagnóstico por imagem
11.
J Nucl Med ; 39(12): 2022-7, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9867135

RESUMO

UNLABELLED: A high-resolution PET system for small animals was tested for its applicability to the investigation of regional myocardial blood flow (MBF) in rabbits. METHODS: Nineteen measurements were performed in 10 closed-chest anesthetized rabbits at baseline and during infusions of adenosine (0.2 mg/kg/min) and propranolol (0.20-1.20 mg slow infusion) to obtain a wide range of MBF. Myocardial blood flow was assessed both by dynamic 13N-ammonia PET and by colored microspheres. Blood was withdrawn directly from the femoral artery, and arterial 13N activity was measured by coincidence type gamma detection system for the input function. Nitrogen-13 myocardial uptake was calculated by dividing the myocardial 13N activity by the integral value of the input function. RESULTS: Three or four contiguous cross-sectional myocardial images were obtained after 13N-ammonia injection. The left ventricular wall and cardiac cavity were clearly visualized. Moreover, initial passage of the tracer through the heart was obtained with serial 10-sec PET images. Nitrogen-13 myocardial uptake correlated well with flow measured with microspheres (r = 0.88). CONCLUSION: Our cardiac PET system can be used for in vivo imaging and quantitation of MBF in small animals and may play an important role in the future study of animal models of cardiovascular diseases.


Assuntos
Circulação Coronária , Coração/diagnóstico por imagem , Tomografia Computadorizada de Emissão/métodos , Adenosina/farmacologia , Amônia/farmacocinética , Animais , Circulação Coronária/efeitos dos fármacos , Coração/fisiologia , Frequência Cardíaca/efeitos dos fármacos , Masculino , Miocárdio/metabolismo , Radioisótopos de Nitrogênio/farmacocinética , Propranolol/farmacologia , Coelhos , Sensibilidade e Especificidade , Sístole/efeitos dos fármacos , Distribuição Tecidual
12.
Pancreas ; 14(4): 407-14, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9163788

RESUMO

The junction between the main pancreatic duct and the accessory duct has been thought to be the site of fusion between the ducts of the ventral and the dorsal primordia of the pancreas. The aim of this study was to investigate the fusion point between the ventral and the dorsal pancreatic ducts and to determine whether there is any relationship between the configuration of the pancreatic ducts and the manner of embryological fusion. Pancreatography was performed at 22 consecutive autopsies. Immunohistochemical staining of pancreatic polypeptide (PP) was performed because PP cells were rich in the ventral pancreas but poor in the dorsal pancreas. We identified two types of fusion. In one type, the ventral and the dorsal pancreatic ducts fuse at their junction (one-point fusion). In the other type, the two ducts fuse not only at the proximal site but at a second, more distal site (two-point fusion). Analysis of the pancreatograms showed that the distance between the junction and the major papilla in two-point fusion is significantly shorter than in one-point fusion (p < 0.01). These results indicate a close correlation between the pattern seen on pancreatograms and the manner of embryological fusion.


Assuntos
Fusão de Membrana/fisiologia , Pâncreas/embriologia , Idoso , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Pâncreas/anatomia & histologia , Pâncreas/metabolismo , Ductos Pancreáticos/diagnóstico por imagem , Ductos Pancreáticos/embriologia , Ductos Pancreáticos/metabolismo , Radiografia
13.
Gene ; 175(1-2): 157-65, 1996 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-8917093

RESUMO

Bacteriophage phi gle was induced from a lysogenic Lactobacillus strain Gle. phi gle genome is double-stranded DNA of approximately 42.5 kilo-base (kb) pairs. SDS poly-acrylamide gel electrophoresis demonstrated that the phage particles contain 4 major structural (capsid) proteins, gpB, gpG, gpO, and gpP, whose molecular weights (MW) are estimated to be 64, 43, 29 and 26 kilodaltons (kDa), respectively. More than 16 minor proteins ranging from 113 to 9.6 kDa were also detected. The genes for the major capsid proteins were cloned and each DNA sequence was determined. N-terminal amino acid alignments determined by protein sequencing completely coincided with those deduced from the nucleotide sequences.


Assuntos
Bacteriófagos/química , Capsídeo/genética , Genes Virais/genética , Lactobacillus/virologia , Proteínas Estruturais Virais/genética , Sequência de Aminoácidos , Bacteriófagos/ultraestrutura , Sequência de Bases , Mapeamento Cromossômico , Clonagem Molecular , Microscopia Eletrônica , Dados de Sequência Molecular , Alinhamento de Sequência
14.
J Cardiovasc Pharmacol ; 28(1): 134-41, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8797147

RESUMO

Calcium channel blockers are commonly used for the treatment of ischemic heart disease, but their effects on myocardial infarct size (IS) after reperfusion are not well known. Enflurane-anesthetized open-chest pigs subjected to 60-min left anterior descending coronary artery (LAD) occlusion followed by 3-h reperfusion were referred to one of the four experimental groups. Beginning 10 min before the onset of reperfusion, pigs in group A received diltiazem (7.5 micrograms/kg/min) retrogradely infused into the coronary vein for 30 min. In group B, the same amount of diltiazem was infused into the right atrium. A corresponding volume of saline was infused into the coronary vein in group C or into the right atrium in group D. IS expressed as a percentage of the myocardium at risk was significantly smaller (p < 0.01) in group A (33 +/- 14%; mean +/- SD) than in groups B (58 +/- 11%), C (58 +/- 11%), and D(63 +/- 10%). After reperfusion, functional recovery of the ischemic myocardium, determined by ultrasound crystals, was significantly more improved (p < 0.05) in group A as compared with other groups. The ischemic and nonischemic regional myocardial blood flow (RMBF), determined by radioactive microspheres, did not differ between four groups. Coronary venous retroinfusion of diltiazem had a myocardial protective effect in the porcine experimental model of acute coronary occlusion/reperfusion, whereas intravenous drug administration was not effective. The protective effect could not be attributed to washout of toxic metabolites from the ischemic area or to improved microcirculation. It was probably related to a pronounced accumulation of the calcium-channel blocker diltiazem in the ischemic myocardium achieved by the coronary venous route of delivery.


Assuntos
Bloqueadores dos Canais de Cálcio/administração & dosagem , Diltiazem/administração & dosagem , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Vasos Coronários , Diltiazem/farmacologia , Infarto do Miocárdio/patologia , Miocárdio/patologia , Suínos
16.
Artif Organs ; 19(7): 665-70, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8572970

RESUMO

Flow visualization is widely applied to evaluate rotary blood pumps; however, it is very difficult to visualize flow near the vanes of centrifugal blood pumps because the rotational speed of the impeller is usually several thousand rpm. In this study, a tracer method with a high speed video camera that can take more than 2,000 frames/s was utilized for flow visualization together with computer-assisted image measurement. This method visualized the complex secondary flow pattern near the vanes of the impeller, such as the vortex and recirculation. It also visualized the enhanced washout effect by the secondary washout vanes on the backside of the impeller. The proposed method was effective to analyze the flow pattern in the centrifugal blood pump by providing useful information for better design of the pump hemolysis and thrombus formation.


Assuntos
Coração Auxiliar/normas , Gravação de Videoteipe , Velocidade do Fluxo Sanguíneo/fisiologia , Hemólise/fisiologia , Processamento de Imagem Assistida por Computador , Rotação , Trombose/prevenção & controle
17.
Biomaterials ; 14(6): 442-8, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8507791

RESUMO

Surface modification of polyurethane by glow-discharge treatment and subsequent graft polymerization of acrylamide was studied. The modified hydrophilic surfaces were characterized by the measurements of dynamic contact angle and zeta potentials and examined for protein adsorption behaviour and platelet adhesion. Data from in vitro and ex vivo experiments indicated a reduction of protein adsorption and platelet adhesion for the hydrophillic graft polymers, the extent of which was correlated to polymer graft density.


Assuntos
Acrilamidas , Adesividade Plaquetária/efeitos dos fármacos , Poliuretanos/farmacologia , Adsorção , Animais , Materiais Biocompatíveis , Interações Medicamentosas , Polímeros , Poliuretanos/química , Coelhos
18.
J Biomed Mater Res ; 27(3): 335-43, 1993 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8360203

RESUMO

In an attempt to develop blood-contacting tubes that can be applied for short-term uses with a reduced heparin concentration or, ideally, without heparinization, we evaluated the blood compatibility of polymeric materials with a rabbit ex vivo shunt model. The shunt tubes employed were made of silicone, plasticized poly(vinyl chloride) (PVC), and segmented poly(ether urethane) (PU). In addition, two kinds of surface-modified tube were used: poly(vinyl alcohol) (PVA)-coated PVC and poly(dimethylacrylamide) (PDMAA)-grafted PU. The ex vivo shunt results correlated well with protein adsorption and platelet adhesion in vitro. The following order for the extent of platelet deposition was given, irrespective of the blood-contacting duration: PDMAA-grafted PU < PVA-coated PVC < PU < silicone, PVC. It is likely that many platelet aggregates detached from the PVA-coated PVC surface. For PDMAA-grafted PU, no trace of detachment of aggregates could be detected on any of the SEM photographs. The number and morphology of blood cells adhered onto the tube surfaces during ex vivo shunting were dependent on the kind of polymer surfaces, the blood exposure time, and the flow rate of blood.


Assuntos
Derivação Arteriovenosa Cirúrgica , Teste de Materiais , Adesividade Plaquetária , Polímeros , Animais , Adesão Celular , Fibrinolíticos/química , Leucócitos/citologia , Coelhos , Propriedades de Superfície
19.
Cardiovasc Drugs Ther ; 7(1): 159-67, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8097926

RESUMO

Previous studies have demonstrated pronounced ischemic zone myocardial concentrations of metoprolol following coronary venous retroinfusion in pigs with coronary artery ligation. The effect of coronary venous retroinfusion of metroprolol on myocardial infarct size was studied in 16 pentobarbital-anesthetized open-chest pigs undergoing 60-minute occlusion of the left anterior descending coronary artery followed by 3 hours of reperfusion. Pigs in the experimental group (n = 8) were given 0.4 mg/kg (1.0 mg/ml) of metroprolol via the anterior interventricular vein over a period of 5 minutes, beginning immediately after coronary occlusion followed by 0.2 mg/kg/hr intravenously. Control pigs (n = 8) received the same volume of saline as the treated group. The risk area and the necrotic area were assessed by monastral blue dye and triphenyl tetrazolium chloride staining, respectively. Metoprolol did not influence hemodynamics. Plasma concentrations of metoprolol were within therapeutic levels. The administration of the beta-blocker resulted in a trend toward reduced norepinephrine concentrations, both in the aorta and coronary vein after coronary occlusion, but it did not prevent norepinephrine overflow following reperfusion. Infarct size expressed as a percentage of the risk area was 77 +/- 11% in the control group and 75 +/- 12% (mean +/- SD; NS) in the treated group. Thus, metoprolol retroinfusion did not reduce infarct size and did not prevent catecholamine overflow after reperfusion. It is concluded that the beneficial effects of metroprolol in acute infarction are probably unrelated to local beta-adrenergic blockade, at least in the pig, an animal with a paucity of coronary collateral blood flow.


Assuntos
Metoprolol/uso terapêutico , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Antagonistas Adrenérgicos beta/sangue , Antagonistas Adrenérgicos beta/uso terapêutico , Animais , Vasos Coronários/fisiologia , Feminino , Hemodinâmica/efeitos dos fármacos , Infusões Intravenosas , Masculino , Metoprolol/sangue , Infarto do Miocárdio/sangue , Isquemia Miocárdica/sangue , Isquemia Miocárdica/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/sangue , Norepinefrina/sangue , Suínos , Função Ventricular Esquerda/efeitos dos fármacos
20.
J Cardiovasc Pharmacol ; 18(4): 581-8, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1724536

RESUMO

The effects of the antiarrhythmic drugs lidocaine and bretylium tosylate on myocardial necrosis were studied in anesthetized pigs subjected to 60-min coronary occlusion followed by 3-h reperfusion. Group A (n = 7) received lidocaine (average dose +/- SD = 1,828 +/- 515 mg) before and during coronary occlusion and after reperfusion; the other series (group B, n = 7) received bretylium tosylate (3,457 +/- 1,323 mg). Infarct size was 16.3 +/- 14.7% in the lidocaine group as compared with 68.6 +/- 12.6% (p less than 0.01) in the bretylium group. In vitro release of superoxide anion from porcine granulocytes was studied using the lucigenin-dependent chemiluminescence technique. Lidocaine significantly reduced the peak chemiluminescence response to zymosan from 3.34 +/- 0.44 without lidocaine to 2.23 +/- 0.46 (p less than 0.01) and 1.06 +/- 0.17 mV (p less than 0.001), with lidocaine concentrations of 20 and 200 micrograms/ml, respectively. Bretylium had no effect on the chemiluminescence response. Adherence of porcine granulocytes to plastic was also reduced from 332 +/- 32 cells/mm2 (no lidocaine) to 247 +/- 35 and 206 +/- 26 cells/mm2 with lidocaine concentrations of 20 and 200 micrograms/ml, respectively (p less than 0.001). Bretylium had no significant effect. Eight additional bretylium-treated pigs received either rabbit antiporcine granulocyte serum (group C, n = 4) to reduce circulating granulocytes or nonimmune serum (group D, n = 4). Infract size in the granulocyte-depleted pigs was 26.6 +/- 5.6% as compared with 51.4 +/- 5.5% in pigs that received nonimmune serum (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Tosilato de Bretílio/farmacologia , Doença das Coronárias/patologia , Lidocaína/farmacologia , Infarto do Miocárdio/patologia , Traumatismo por Reperfusão Miocárdica/patologia , Animais , Arteriopatias Oclusivas/fisiopatologia , Tosilato de Bretílio/farmacocinética , Circulação Coronária/efeitos dos fármacos , Doença das Coronárias/complicações , Doença das Coronárias/tratamento farmacológico , Granulócitos/imunologia , Granulócitos/metabolismo , Técnicas In Vitro , Teste de Inibição de Aderência Leucocítica , Lidocaína/farmacocinética , Medições Luminescentes , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/etiologia , Traumatismo por Reperfusão Miocárdica/complicações , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Necrose/patologia , Consumo de Oxigênio/efeitos dos fármacos , Superóxidos/metabolismo , Suínos
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