Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
1.
Br J Radiol ; 85(1011): e49-52, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22391499

RESUMO

We present the case of a 79-year-old female with symptomatic cavernous haemangioma of the liver. The patient had experienced progressive right lateral abdominal pain for years despite increased painkiller use. Surgical resection or transarterial embolisation was not recommended because of the patient's age, cardiovascular comorbidities and large tumour size. Therefore, the patient was treated with 3-dimensional conformal radiotherapy (RT) with a total dose of 30 Gy in 15 fractions. Following RT, the painkillers were tapered from the third month, and complete symptomatic remission was achieved after the ninth month. The measured tumour volume from serial images pre-RT and 3, 9 and 15 months post-RT was 400 ml, 372 ml, 185 ml and 140 ml, respectively. The most dramatic volumetric reduction was found between 3 and 9 months post-RT, whereas the change before or after this period was minimal. The time course of the radiological volumetric changes correlated with that of the clinical symptoms. In addition, the observed vascular changes on serial imaging studies were consistent with the assumed radiobiological effects after fractionated RT.


Assuntos
Hemangioma Cavernoso , Neoplasias Hepáticas , Dor Abdominal/etiologia , Idoso , Feminino , Hemangioma Cavernoso/diagnóstico por imagem , Hemangioma Cavernoso/patologia , Hemangioma Cavernoso/radioterapia , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/radioterapia , Imageamento por Ressonância Magnética , Tomografia Computadorizada por Raios X
2.
AJNR Am J Neuroradiol ; 32(1): 159-64, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21051509

RESUMO

BACKGROUND AND PURPOSE: AICA aneurysms are rare and a challenge to treat surgically. We present our experience of the angiographic results and the clinical outcomes for 9 AICA aneurysms treated by EVT. MATERIALS AND METHODS: Between 1997 and 2009, EVT was attempted for 9 AICA aneurysms. Six patients presented with SAH, and 3 aneurysms were found incidentally. The location of the aneurysms was the proximal AICA in 7 and the distal AICA in 2. Five aneurysms originated from an AICA-PICA variant. Clinical outcomes and procedural complications were evaluated, and angiography was performed 6, 12, and 24 months after embolization to confirm recanalization of the coiled aneurysm. RESULTS: EVT was technically successful in 7 patients (78%). Surgical trapping was performed in 1 patient after failure of EVT, and another aneurysm occluded spontaneously, along with the parent artery during EVT. In 7 patients, the AICAs had good patency on postoperative angiography. Stent-assisted coiling was performed in 3 patients. Follow-up angiographies were performed in 7 patients and showed no evidence of recanalization or progressive occlusion with further thrombosis except in 1 patient. There was no evidence of aneurysm rupture during the follow-up period, and 8 patients were able to perform all usual activities (mRS score, 0-1). CONCLUSIONS: EVT may provide a feasible and safe option as an alternative, though a microsurgical option is initially considered for the management of AICA aneurysms. Further follow-up and more experience are also necessary.


Assuntos
Doenças Cerebelares/diagnóstico por imagem , Doenças Cerebelares/cirurgia , Cerebelo/irrigação sanguínea , Embolização Terapêutica/instrumentação , Embolização Terapêutica/métodos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Adulto , Idoso , Cerebelo/diagnóstico por imagem , Cerebelo/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia , Resultado do Tratamento
3.
AJNR Am J Neuroradiol ; 31(1): 155-60, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19749226

RESUMO

BACKGROUND AND PURPOSE: Intracranial fusiform aneurysms, which incorporate the branch vessel and require salvaging of the parent vessel, are difficult to manage. The goal of this study was to evaluate the efficacy of reconstructive endovascular treatment of intracranial fusiform aneurysms by using a 1-stage procedure with a stent and balloon. MATERIALS AND METHODS: During a 3-year period, 20 patients with 20 intracranial fusiform aneurysms were treated by using a 1-stage procedure involving a balloon and stent. Subarachnoid hemorrhage was present in 15 patients. Five aneurysms were located in the anterior circulation and 15, in the posterior circulation. Clinical outcomes and periprocedural complications were evaluated in all patients. The extent of coil packing was evaluated by control angiography after embolization and classified as either complete occlusion or partial occlusion. Angiography was performed 6, 12, and 24 months after embolization to evaluate stent patency and coil packing. RESULTS: The 1-stage procedure by using a combination of balloon and stent was technically successful in all patients. There were no complications related to the procedure, complete occlusion was obtained in 16 patients, and partial occlusion, in 4 patients. All patients recovered well except for 2 who died due to causes unrelated to the procedure. Clinical follow-up was performed in all surviving patients at a mean of 12.3 months (range, 7-24 months), and angiography showed that the patent parent arteries were free of aneurysm recanalization or in-stent stenosis. CONCLUSIONS: This 1-stage procedure may provide a feasible and safe treatment strategy for the management of intracranial fusiform aneurysms that are not amenable to deconstructive embolization.


Assuntos
Oclusão com Balão , Aneurisma Intracraniano/terapia , Stents , Adulto , Oclusão com Balão/métodos , Terapia Combinada/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Implantação de Prótese/métodos , Estudos Retrospectivos
4.
AJNR Am J Neuroradiol ; 28(4): 709-13, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17416826

RESUMO

BACKGROUND AND PURPOSE: "Gossypiboma" is a term used to describe a mass within the body that comprises a cotton matrix surrounded by a foreign-body reaction, which is extremely rare after spinal surgery. The purpose of this study was to describe the clinical and MR imaging features of gossypibomas in the paravertebral area of 7 patients. MATERIALS AND METHODS: Between October 1999 and December 2005, 7 cases of paravertebral gossypibomas were confirmed pathologically at 2 institutions. The clinical features were reviewed retrospectively. We recorded MR imaging features and differential MR imaging-based diagnoses. RESULTS: All patients were symptomatic; the most frequent symptom was nonspecific back or neck pain. None of the patients presented with signs of infection or required surgery urgently. In 3 of the 7 patients, gossypiboma was included in the preoperative differential imaging diagnosis. In all patients, the gossypiboma was located in the vicinity of the initial site of surgery. Typically, gossypibomas were visible in T2-weighted images as a mass with a hyperintense center and hypointense rim and exhibited strong peripheral enhancement in contrast-enhanced images. Retained surgical gauze was removed surgically from 4 patients; in the remaining patients, the surgical specimens contained suture threads. CONCLUSION: Gossypiboma should be included in the differential diagnosis of the paravertebral mass when a mass with a hyperintense center and peripheral hypointense rim on T2-weighted images and strong peripheral rim enhancement on contrast-enhanced T1-weighted MR images is seen in postoperative patients.


Assuntos
Reação a Corpo Estranho/diagnóstico , Laminectomia , Imageamento por Ressonância Magnética , Tampões de Gaze Cirúrgicos , Suturas , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Coluna Vertebral
5.
AJNR Am J Neuroradiol ; 27(10): 2078-82, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17110671

RESUMO

BACKGROUND AND PURPOSE: To describe the results of transvenous embolizations of cavernous dural arteriovenous fistua (cDAVF) with an emphasis on identifying the incidence, characteristics, and management strategies associated with the complications of transvenous embolization of cDAVFs. METHODS: Fifty-six consecutive patients who were treated by transvenous embolization for cDAVFs were reviewed. The approach routes, angiographic results, complications, and clinical outcome were assessed. RESULTS: Retrograde inferior petrosal sinus (n = 36), transfacial vein (n = 7), transcontralateral intercavernous sinus (n = 4), and direct superior ophthalmic vein (n = 3) approaches were used. Angiographic results showed complete occlusion (n = 29), nearly complete occlusion (n = 13), and incomplete occlusion (n = 14). Complications associated with the procedures were cranial nerve palsy (n = 6), venous perforation (n = 3), and brain stem congestion (n = 2). The cranial nerve signs resolved with conservative treatment. Venous perforations were managed by coil embolizations at the site of the tear with no significant neurologic sequelae. One case of brain stem congestion resulted in hemiplegia after conservative treatment. The other case showed venous congestion as a result of rerouting of the shunted flow after venous embolization that was successfully managed by covered stent deployment for occlusion of the residual feeders. Clinical follow-up data were available in 46 patients. Complete resolution or improvement of symptoms was seen in 42 patients (91%). CONCLUSIONS: Cavernous DAVFs may be effectively treated by transvenous embolization. However, the procedure can be associated with various complications, some of which can potentially result in significant morbidity. Prompt diagnosis of the complications with appropriate management strategies is mandatory for a safe procedure.


Assuntos
Malformações Vasculares do Sistema Nervoso Central/terapia , Embolização Terapêutica/efeitos adversos , Embolização Terapêutica/métodos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
6.
AJNR Am J Neuroradiol ; 27(4): 780-5, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16611764

RESUMO

BACKGROUND AND PURPOSE: The goal of thrombolytic therapy in patients with acute ischemic stroke is early recanalization, but this may result in delayed reperfusion injury. The purpose of this study was to evaluate the neuroprotective effect of agmatine in a transient ischemic cat model by using MR perfusion imaging and histopathologic analyses. METHOD: One-hour temporary occlusion of the left middle cerebral artery of cats was performed in the control ischemia group (n = 10), and 100 mg/kg of agmatine was intravenously injected immediately after recanalization in the agmatine-treated group (n = 15). MR imaging was performed at 1, 24, and 48 hours after recanalization, and the perfusion patterns were investigated. Terminal-deoxynucleotidyl transferase mediated nick and end-labeling (TUNEL) and hematoxylin-eosin (H&E) stainings were performed at the corresponding sections. RESULTS: In the control ischemia group, the number of TUNEL-positive cells was significantly increased in the areas with reperfusion hyperemia (P < .05). In the agmatine-treated group, no significant increase in the number of TUNEL-positive cells was noted in the areas of reperfusion hyperemia. The difference in the number of TUNEL-positive cells between the control ischemia and agmatine-treated group in the areas of reperfusion hyperemia was significant (P < .05). The total number of TUNEL-positive cells and the area of severe ischemic neuronal damage on H&E stain were also significantly attenuated in the agmatine-treated cats compared with the control ischemia cats (P < .05). CONCLUSION: Our results suggest that agmatine has neuroprotective effects against reperfusion injury and ischemia.


Assuntos
Agmatina/uso terapêutico , Ataque Isquêmico Transitório/tratamento farmacológico , Ataque Isquêmico Transitório/patologia , Imageamento por Ressonância Magnética , Animais , Gatos , Circulação Cerebrovascular , Modelos Animais de Doenças , Ataque Isquêmico Transitório/fisiopatologia , Fatores de Tempo
7.
Hong Kong Med J ; 12(2): 115-8, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16603778

RESUMO

OBJECTIVE: To investigate the management of hypertension by private doctors in Hong Kong. DESIGN: Self-administered questionnaire survey. SETTING: Hong Kong. PARTICIPANTS: Private doctors from all districts in Hong Kong selected by simple random sampling from the website of "The Hong Kong Doctors Homepage" from March to June 2005. MAIN OUTCOME MEASURES: Practice of blood pressure measurement and the treatment prescribed to hypertensive patients. RESULTS: A total of 225 (46%) completed questionnaires were analysed. Only 24.4% of the respondents measured blood pressure in all new patients aged above 18 years. A total of 28.0% of doctors reported that hypertensive status was unknown in over 30% of their patients prior to their first clinic visit when it was consequently diagnosed. Calcium channel blockers (31%), angiotensin-converting enzyme inhibitors (28.5%), diuretics (27.5%), and beta-blockers (21.2%) were the most commonly prescribed antihypertensive medication. Drug efficacy was the reason cited by more than half (56.9%) of doctors for selecting a given drug. Public education about hypertension was considered insufficient by 66.2% of doctors and 32% believed that self-medication would have a very significant effect on drug compliance. CONCLUSIONS: In private clinics, blood pressure measurement should become a routine procedure. There is a need to raise public awareness of hypertension.


Assuntos
Hipertensão/prevenção & controle , Padrões de Prática Médica , Adulto , Anti-Hipertensivos/uso terapêutico , Determinação da Pressão Arterial , Pesquisas sobre Atenção à Saúde , Hong Kong , Humanos , Programas de Rastreamento , Educação de Pacientes como Assunto
8.
J Chem Phys ; 121(24): 12626-31, 2004 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-15606287

RESUMO

It is generally agreed that, in most cases, surfactants are required to obtain stable polymeric nanoparticle dispersions. Here, we report a method which can be used to produce surfactant free yet stable polymeric nanoparticle dispersions. This method is based on explored mechanism of selective solvation of nanoparticles and EPD (electron pair donor)/EPA (electron pair acceptor) complexes formed among solvent and nonsolvent molecules. Using polyimide P84 (copolyimide 3,3(') 4,4(')-benzophenone tetracarboxylic dianhydride and 80% methylphenylene diamine+20% methylene dianiline) as the model polymer, this mechanism was realized through a combined liquid-liquid phase separation and solvent/nonsolvent mixing technology. Surfactant-free polyimide nanoparticles (<100 nm) were produced. Experimental details and principles of this technology were given based on the ternary diffusion, the liquid-liquid phase separation and the advanced nucleation and growth theory. Two types of methods [denoted as the forward titration method and the backward titration (BT) method] were examined. It was found that the BT method is extremely helpful to prepare polyimide nanoparticles (<100 nm). As another important aspect, explored stabilization mechanism of the resultant nanoparticle dispersions was supported by the comparative experiments, implying that selective solvation of nanoparticles and EPD/EPA complexes may play key roles in stabilization.


Assuntos
Nanotecnologia/métodos , Polímeros/química , Solventes/química , Tensoativos/química , Benzofenonas/química , Modelos Químicos , Nanoestruturas , Tamanho da Partícula , Fenilenodiaminas/química , Resinas Sintéticas/química
9.
J Microencapsul ; 18(5): 637-49, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11508769

RESUMO

Poly(D,L-lactide-co-glycolide) (PLG, 65:35) was used to encapsulate bovine serum albumin (BSA) using a water-in-oil-in-water (W/O/W) double emulsion solvent extraction technique. To investigate the effects of an inner water/oil ratio on microsphere characteristics, microspheres were fabricated using four different formulations with a fixed oil volume of 12ml and the inner aqueous phase volume of 0.2ml, 0.3 ml, 0.4ml or 0.5 ml, respectively. Spherical microspheres were obtained after collection by filtration for formulations employing any of the four different inner water/oil ratios. However, microspheres with smaller inner water volumes tend to collapse after vacuum drying. The surface of the formulation with a higher inner water/oil ratio was shown to possess many more pores than that of the formulations with lower inner water/oil ratios. These pores may facilitate the water withdrawal during vacuum drying. Furthermore, microspheres with the lowest inner water/oil ratio (1/60) had higher initial burst release due to its larger surface area. However, microspheres with the highest inner water volume yield a faster release profile of BSA due to interconnected voids within microspheres and more pores on the surface. Therefore, the inner water/oil ratio is a crucial factor in the W/O/W double emulsion technique affecting the morphology and release kinetics of the resulting microspheres.


Assuntos
Sistemas de Liberação de Medicamentos , Emulsões , Poliglactina 910/administração & dosagem , Microscopia , Microesferas , Tamanho da Partícula
10.
J Control Release ; 75(1-2): 11-25, 2001 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-11451493

RESUMO

A study has been carried out to investigate the degradation and protein release mechanisms of BSA-loaded microspheres made with auto-catalyzed poly(ortho esters) (POEs) of varying diol composition and molecular weights. Due to the instability of the POE/dichloromethane primary emulsion, microspheres made using the W/O/W double emulsion solvent extraction/evaporation method showed a multivesicular internal structure. An O/W single emulsion process yielded dense POE microspheres. Using electron scanning microscopy, the microspheres were observed to erode throughout their matrices with increasing internal pore sizes and a steady loss of mass. However, despite a substantial weight loss of almost 80% after an in vitro period of 129 days, the molecular weight of the polymer remained relatively unchanged with loss averaging about 18 and 32% for low- and high-molecular-weight POEs, respectively. Such constancy in molecular weight was similarly reflected in the glass transition temperature of the degrading microspheres. The differences in both the molecular weight loss and polydispersity index changes depended largely on the molecular weight of the polymer. For protein release of POE microspheres, an induction period followed by BSA release for a period of 3 to 10 days was observed. The lag time depended on the hydrophilicity and the molecular weight of the polymer as well as the morphology of the microspheres. Protein release was incomplete, possibly due to the slow degradation of the POE polymers, protein aggregation and protein degradation.


Assuntos
Materiais Biocompatíveis/química , Sistemas de Liberação de Medicamentos , Microesferas , Preparações Farmacêuticas/administração & dosagem , Polímeros/química , Acetatos , Varredura Diferencial de Calorimetria , Cromatografia em Gel , Eletroforese em Gel de Poliacrilamida , Emulsões , Microscopia Eletrônica de Varredura , Peso Molecular , Tamanho da Partícula , Soroalbumina Bovina , Viscosidade
11.
J Control Release ; 75(1-2): 115-28, 2001 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-11451502

RESUMO

Poly(ortho ester) (POE)-poly (ethylene glycol) (PEG) triblock copolymers (POE-PEG-POE) with different PEG contents were synthesised as carriers for controlled protein delivery. POE-PEG-POE microspheres containing bovine serum albumin (BSA) were prepared using a double-emulsion (water-in-oil-in-water) process. In this first paper of a two-part series, we report the fundamentals of the fabrication and characterization of POE-PEG-POE microspheres. Because the triblock copolymer is more hydrophilic than neat poly(ortho ester), the triblock copolymer yields a more stable first emulsion (water-in-oil) and a greater BSA encapsulation efficiency (90% vs. 30%). No BSA is found on POE-PEG-POE microsphere surfaces measured by X-ray photoelectron spectroscopy, while uniform BSA distributions are observed within the microspheres by confocal microscopy. SEM pictures show that an increase in PEG content results in microspheres with a denser cross-section because of a more stable first emulsion and better affinity between the copolymer and water. POE-PEG(20%)-POE suffers significant swelling during the fabrication process and yields the biggest microspheres. However, the POE-PEG(30%)-POE microspheres are much smaller since the dissolution loss of POE-PEG(30%)-POE in the external water phase may be much higher than that of POE-PEG(20%)-POE. The salt concentration in the external water phase significantly affects the morphology of the resultant microspheres. Microspheres with a dense wall are produced when using pure water as the external water phase. Polymer concentration has less impact on BSA encapsulation efficiency but has a considerable effect on microsphere size and morphology. Increasing the concentration of the polyvinyl alcohol emulsifier does not cause an obvious decrease in microsphere size. However, increased BSA loading results in bigger microspheres.


Assuntos
Poloxâmero/química , Proteínas/química , Algoritmos , Fenômenos Químicos , Físico-Química , Emulsões , Microscopia Eletrônica de Varredura , Microesferas , Peso Molecular , Tamanho da Partícula , Álcool de Polivinil/química , Proteínas/administração & dosagem , Soroalbumina Bovina , Solventes , Viscosidade
12.
J Control Release ; 75(1-2): 129-41, 2001 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-11451503

RESUMO

The first paper of this series presented the fabrication and characterization of POE-PEG-POE triblock copolymeric microspheres containing protein. In this paper, we focus on the polymer erosion and the mechanism of protein release. Fourteen-week in vitro behaviors of POE-PEG-POE microspheres loaded with bovine serum albumin (BSA) have been monitored. SEM micrographs reveal that after 14-week incubation in PBS buffer, pH 7.4, 37 degrees C, the polymeric particles remain spherical despite mass loss of almost 90%. On the other hand, molecular weight undergoes a high initial loss of 38% and 44% during the first 2-week incubation for POE-PEG(5%)-POE and POE-PEG(10%)-POE, respectively. Then, it keeps relatively unchanged over 12 weeks. However, POE-PEG(20%)-POE copolymer provides a better compatibility between the POE and PEG blocks. Hydrolysis is homogeneous through the polymer backbone. Thus, its molecular weight remains relatively constant and mass loss shows quite sustained over the 14-week in vitro release. The similar phenomena are observed in the polydispersity index of the degrading copolymers. SDS-PAGE of the encapsulated BSA within the POE-PEG(5%)-POE microspheres displays that the structural integrity of BSA is intact for at least 8 weeks due to a mild environment provided by the copolymer. In addition, XPS and FTIR are utilized to investigate protein behaviors in the degrading microspheres. Protein release from the POE-PEG-POE microspheres shows a biphasic pattern, characterized by an initial stage followed by a non-detectable release. The non-release phase is dominated by either slow polymer degradation or dense microsphere matrix structures. The microsphere formulation is optimized and a sustained protein release over 2 weeks is achieved by using POE-PEG(20%)-POE at a high protein loading.


Assuntos
Poloxâmero/química , Proteínas/química , Animais , Bovinos , Composição de Medicamentos , Eletroforese em Gel de Poliacrilamida , Microscopia Eletrônica de Varredura , Microesferas , Peso Molecular , Tamanho da Partícula , Proteínas/administração & dosagem , Soroalbumina Bovina , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier
13.
AJNR Am J Neuroradiol ; 22(6): 1043-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11415895

RESUMO

BACKGROUND AND PURPOSE: Functional MR (fMR) imaging is based on changes in regional blood flow. The purpose of this study was to evaluate the role of fMR imaging for detection of a vascular compromised status in the occipital lobe in patients with ischemia in the visual cortex. METHODS: We performed fMR imaging in seven control subjects and seven patients with symptoms and signs of visual cortical transient ischemia and/or infarct. fMR imaging was performed using a gradient-echo sequence with the 2D fast low-angle shot technique. An axial slice including both visual cortices was selected, and stimulation of the visual cortex was performed using a red photostimulator. The number of activated pixels in each primary visual cortex area were counted and an asymmetry ratio [AR (%) = 100 x (R-L)/(R+L)/2] was calculated. Patients and control subjects underwent visual field examination, conventional MR imaging, and vascular imaging (MR angiography in all patients and control subjects, conventional catheter angiography in two patients). fMR imaging results were compared with the results of a visual field examination, conventional MR imaging, and vascular imaging. RESULTS: fMR imaging of the patients showed significant activation asymmetry (P <.05) compared with that of control subjects. Vascular abnormalities in the posterior circulation were found in all seven patients. By conventional MR imaging, five patients were found to have infarction in the occipital lobe and the remaining two patients showed no abnormality. In visual field examination, six of the seven patients showed homonymous hemi- or quadrantanopsia suggesting postchiasmic abnormalities, and the remaining patient had normal findings. fMR imaging showed decreased activity in the visual cortices corresponding to vascular abnormalities (seven of seven patients), permanent infarction (five of seven patients), or visual field defect (six of seven patients). Two patients with normal conventional MR imaging had vascular lesions in the posterior circulation, and fMR imaging showed decreased activity in the corresponding visual cortices. One patient with normal visual field examination had multifocal stenosis in the posterior cerebral artery without infarction, and fMR imaging showed decreased activity in the corresponding visual cortex. CONCLUSION: fMR imaging of the visual cortex may be a sensitive method for the detection of vascular-compromised status in the occipital lobe.


Assuntos
Infarto Cerebral/diagnóstico , Ataque Isquêmico Transitório/diagnóstico , Imageamento por Ressonância Magnética , Córtex Visual/irrigação sanguínea , Adulto , Idoso , Infarto Cerebral/fisiopatologia , Diagnóstico Diferencial , Dominância Cerebral/fisiologia , Feminino , Humanos , Ataque Isquêmico Transitório/fisiopatologia , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Valores de Referência , Fluxo Sanguíneo Regional/fisiologia , Córtex Visual/patologia
14.
AJNR Am J Neuroradiol ; 22(6): 1149-60, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11415912

RESUMO

BACKGROUND AND PURPOSE: Our purpose was to investigate transient MR signal changes on periictal MR images of patients with generalized tonicoclonic seizure or status epilepticus and to evaluate the clinical significance of these findings for differential diagnosis and understanding of the pathophysiology of seizure-induced brain changes. METHODS: Eight patients with MR images that were obtained within 3 days after the onset of generalized tonicoclonic seizure or status epilepticus and that showed seizure-related MR signal changes had their records retrospectively reviewed. T1- and T2-weighted images were obtained of all eight patients. Additional diffusion-weighted images were obtained of five patients during initial examination. After adequate control of the seizure was achieved, follow-up MR imaging was performed. We evaluated the signal changes, location of the lesions, and degree of contrast enhancement on T1- and T2-weighted images and the signal change and apparent diffusion coefficient (ADC) on diffusion-weighted images. We also compared the signal changes of the initial MR images to those of the follow-up MR images. RESULTS: The initial MR images revealed focally increased T2 signal intensity, swelling, and increased volume of the involved cortical gyrus in all eight patients. The lesions were located in the cortical gray matter or subcortical white matter in seven patients and at the right hippocampus in one. T1-weighted images showed decreased signal intensity at exactly the same location (n = 6) and gyral contrast enhancement (n = 4). Diffusion-weighted images revealed increased signal intensity at the same location and focally reduced ADC. The ADC values were reduced by 6% to 28% compared with either the normal structure opposite the lesion or normal control. Follow-up MR imaging revealed the complete resolution of the abnormal T2 signal change and swelling in five patients, whereas resolution of the swelling with residual increased T2 signal intensity at the ipsilateral hippocampus was observed in the other two patients. For one of the two patients, hippocampal sclerosis was diagnosed. For the remaining one patient, newly developed increased T2 signal intensity was shown. CONCLUSION: The MR signal changes that occur after generalized tonicoclonic seizure or status epilepticus are transient increase of signal intensity and swelling at the cortical gray matter, subcortical white matter, or hippocampus on periictal T2-weighted and diffusion-weighted images. These findings reflect transient cytotoxic and vasogenic edema induced by seizure. The reversibility and typical location of lesions can help exclude the epileptogenic structural lesions.


Assuntos
Edema Encefálico/diagnóstico , Epilepsia Tônico-Clônica/diagnóstico , Aumento da Imagem , Imageamento por Ressonância Magnética , Estado Epiléptico/diagnóstico , Adolescente , Adulto , Encéfalo/patologia , Encéfalo/fisiopatologia , Edema Encefálico/fisiopatologia , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Criança , Pré-Escolar , Difusão , Dominância Cerebral/fisiologia , Epilepsia Tônico-Clônica/fisiopatologia , Feminino , Hipocampo/patologia , Hipocampo/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Estado Epiléptico/fisiopatologia
15.
J Korean Med Sci ; 16(3): 294-302, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11410689

RESUMO

Feasibility of identifying viable myocardium in rest and stress magnetic resonance imaging (MRI) was evaluated using 3 hr occlusion and 30 min reperfusion model of left anterior descending (LAD) coronary artery in 12 felines. At rest MRI, viable myocardium confirmed by 2,3,5-triphenyl tetrazolium chloride (TTC)-staining showed rapid signal intensity (SI) rise followed by gradual decline not significantly different from normal myocardium that the two hyperperfused regions were distinguishable only from the hypoperfused nonviable myocardium. At stress MRI, hyperemia induced perfusion change was most pronounced in normal myocardium with earlier and greater peak enhancement followed by brisk 'washout' phase while minimally augmented enhancement in viable myocardium was still in 'washin' phase. From these findings, it was concluded that viable myocardium is identified in rest and stress MRI as redistributing hypo- perfusion compared to persistent hyper-perfusion of the normal myocardium and the persistent hypo-perfusion of the nonviable myocardium.


Assuntos
Coração/diagnóstico por imagem , Hiperemia/diagnóstico por imagem , Infarto do Miocárdio/diagnóstico por imagem , Traumatismo por Reperfusão Miocárdica/diagnóstico por imagem , Animais , Gatos , Imageamento por Ressonância Magnética , Radiografia , Estresse Fisiológico
16.
Biomaterials ; 22(3): 231-41, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11197498

RESUMO

The surface and internal morphology, drug distribution and release kinetics at 22 degrees C of polyesters such as PCL (polycaprolactone) and PLGA (poly(DL-lactic-co-glycolic acid)) 65:35 microspheres containing BSA (bovine serum albumin) have been investigated in order to understand the relationship amongst morphology, drug distribution and in vitro release profiles and to develop controlled release devices for marine fishes in tropical area. CLSM (confocal laser scanning microscope) micrographs reveal that the polyvinylalcohol (PVA as an emulsifier) concentration in the external water phase strongly influences drug distribution within microspheres and release profiles. The presence of PVA in the internal water phase enhances the stabilization of inner water droplets against coalescence. This results in a more uniform drug distribution and a slower BSA release. Different oil-phase volumes and polymer concentrations yield different solvent exchange and precipitation mechanisms, which lead to different morphologies. A low oil-phase volume yields microspheres with a porous matrix and defective skin surface, which gives a high initial BSA burst as well as a fast release profile. Microspheres fabricated from a low polymer concentration have less defective skin surface, but with a less tortuous inner matrix which results in a more rapid BSA release. A higher BSA loading yields a larger concentration gradient between the emulsion droplet and the continuous water phase as well as between the microspheres and the in vitro medium. The former results in a lower encapsulation efficiency, whereas the latter yields a faster initial burst and a more rapid release profile. High stirring speed can reduce microsphere size, but decreases the yield of microspheres.


Assuntos
Sistemas de Liberação de Medicamentos , Soroalbumina Bovina/administração & dosagem , Biodegradação Ambiental , Emulsões , Cinética , Microscopia Eletrônica de Varredura , Microesferas , Peso Molecular , Tamanho da Partícula , Solventes
17.
Arch Neurol ; 57(10): 1510-2, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11030805

RESUMO

OBJECTIVE: To describe hemidystonia and hemichoreoathetosis in an adult patient with moyamoya disease without a previous history of cerebrovascular accident. DESIGN: Case report. SETTING: Tertiary care center. PATIENT: A 22-year-old woman suddenly developed dystonic spasms in her left hand and left foot after a severe emotional stress. The dyskinesia gradually subsided over the next 4 months. Five months after the onset, she suddenly developed choreoathetoid movement in her right hand and right foot. MAIN OUTCOME AND RESULTS: The patient had both somatic and cortical sensory deficits in the right hand and right foot. Magnetic resonance imaging of the brain showed an infarction at the right putamen and lesions involving the right frontal lobe and the left frontotemporoparietal lobe. Magnetic resonance cerebral angiography showed severe stenoses of both internal carotid arteries at the supraclinoid portion and numerous collateral vessels, compatible with moyamoya disease. Single photon emission tomography of the brain showed hypoperfused areas at the right frontal and left frontotemporoparietal lobes. The choreoathetosis of the right limbs improved markedly, along with improvement of sensory deficits. CONCLUSIONS: To our knowledge, this is the first report of an adult patient presenting with hemidystonia and hemichoreoathetosis as the initial manifestations of moyamoya disease. Arch Neurol. 2000;57:1510-1512


Assuntos
Atetose/diagnóstico , Coreia/diagnóstico , Distonia/diagnóstico , Doença de Moyamoya/complicações , Doença de Moyamoya/diagnóstico , Adulto , Atetose/etiologia , Encéfalo/metabolismo , Encéfalo/patologia , Coreia/etiologia , Distonia/etiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Índice de Gravidade de Doença , Tomografia Computadorizada de Emissão
18.
J Control Release ; 69(1): 81-96, 2000 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-11018548

RESUMO

This study describes the influence of preparation temperature on the various characteristics and release profiles of poly(DL-lactide-co-glycolide) (PLGA) microspheres. The bovine serum albumin (BSA)-loaded microspheres were prepared using the water-in-oil-in-water (w/o/w) technique with poly(vinyl alcohol) as surfactant in the external aqueous phase. We have varied the preparation temperature to observe its effect on microsphere characteristics such as the microsphere shrinking rate during formation, particle size, density, surface and internal morphology, BSA encapsulation efficiency, BSA initial release, microsphere degradation and BSA in vitro release behaviour. During fabrication, a low preparation temperature of 5 degrees C gives the fastest initial but the slowest overall shrinking rate. Microspheres formed at high temperatures of 38 degrees C and 42 degrees C on the other hand have the lowest initial yet the highest overall shrinking rate. Subsequently, microsphere mean size increases and the particle size distribution widens with increase in the preparation temperature. Although all the microspheres have a porous surface as well as internal structure, microspheres fabricated at high temperatures have a uniform internal pore distribution and a very thin dense skin layer, while microspheres fabricated at lower temperatures have a thicker but porous skin layer and bigger pores in the middle of the sphere. Microspheres formed at 33 degrees C are found to give the highest initial burst release. In terms of in vitro release, microspheres fabricated at low temperatures (5 degrees C, 15 degrees C and 22 degrees C) exhibit similar, steady rates. Microspheres formed at higher temperatures however give very low release rates after their initial release. The results obtained suggest that preparation temperature significantly affects microsphere formation, resulting in their structural and protein release profile differences. These differences ultimately work together to affect the initial release and overall release patterns of the microspheres.


Assuntos
Proteínas/química , Algoritmos , Fenômenos Químicos , Físico-Química , Portadores de Fármacos , Composição de Medicamentos , Excipientes , Ácido Láctico , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Microesferas , Tamanho da Partícula , Ácido Poliglicólico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros , Proteínas/administração & dosagem , Soroalbumina Bovina , Solventes , Temperatura
20.
J Dermatol ; 27(1): 27-30, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10692821

RESUMO

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare benign condition affecting principally the head and neck region of young females. We describe a 42-year-old female patient of ALHE showing the typical changes of endothelial cells and features similar to Kimura's disease in histologic and immunohistochemical findings.


Assuntos
Hiperplasia Angiolinfoide com Eosinofilia/patologia , Pele/patologia , Adulto , Antígenos CD/análise , Linfócitos B/química , Linfócitos B/patologia , Complexo CD3/análise , Antígenos CD79 , Feminino , Humanos , Imunoglobulina E/análise , Imuno-Histoquímica , Receptores de Antígenos de Linfócitos B/análise , Linfócitos T/química , Linfócitos T/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...