Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 136
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Aging Cell ; 4(3): 139-45, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15924570

RESUMO

Brain mitochondrial function has been posited to decline with aging. In order to test this hypothesis, cortical and striatal mitochondria were isolated from Fischer 344 rats at 2, 5, 11, 24 and 33 months of age. Mitochondrial membrane potential remained stable through 24 months, declining slightly in mitochondria from both brain regions at 33 months. The ability of calcium to induce mitochondrial swelling and depolarization, characteristics of the permeability transition, was remarkably stable through 24 months of age and increased at advanced ages only for cortical, but not striatal, mitochondria. Striatal mitochondria were more sensitive to calcium than were cortical mitochondria throughout the first 2 years of life. A two-fold increased resistance to calcium was observed in striatal mitochondria between 5 and 11 months. Although these measurements do demonstrate changes in mitochondrial function with aging, the changes in polarization are relatively small and the increased cortical susceptibility to the permeability transition only occurred at very advanced ages. Thus mitochondrial decline with advanced age depends upon brain region.


Assuntos
Envelhecimento/fisiologia , Córtex Cerebral/fisiologia , Corpo Estriado/fisiologia , Mitocôndrias/efeitos dos fármacos , Animais , Cálcio/farmacologia , Feminino , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/fisiologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias/fisiologia , Ratos , Ratos Endogâmicos F344
2.
Cancer Res ; 46(11): 5624-8, 1986 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3756909

RESUMO

Both macrophages and natural killer cells have been implicated in the antimetastatic activity of maleic anhydride-divinyl ether (MVE-5). In the present study, we attempted to utilize anti-asialo-GM1 antibody and 2-chloroadenosine, agents that kill natural killer (NK) cells and macrophages, respectively, to determine the relative contribution of each effector cell type to the overall host defense. These agents were tested in the M109 lung metastasis model in syngeneic BALB/c mice, and the cytotoxic activities of both peritoneal macrophages and splenic NK cells were followed. The most profound antitumor effect was observed when MVE-5 was given before rather than after i.v. tumor inoculation. Treatment i.p. with MVE-5 at 20 mg/kg produced greater than 98% inhibition of subsequent lung metastases when given 2 days prior to tumor. Anti-asialo-GM1 antibody (25 mg/kg, i.p.) and 2-chloroadenosine (50 mg/kg, i.p.) were administered concurrently with MVE-5. Although each agent exhibited greater selectivity for its respective target, the early (Day 2) inhibitory response was nonspecific. By Day 5 after MVE-5 treatment, 2-chloroadenosine only inhibited macrophage tumoricidal activity, and conversely, anti-asialo-GM1 antibody only inhibited NK reactivity. Despite the ability of these agents to increase survival of metastases in control animals, they only slightly abrogated the antimetastatic activity of MVE-5. Our data suggest that caution should be exercised in using these agents to discriminate macrophage and NK responses.


Assuntos
Adenosina/análogos & derivados , Citotoxicidade Imunológica/efeitos dos fármacos , Gangliosídeo G(M1) , Glicoesfingolipídeos/imunologia , Imunidade Celular/efeitos dos fármacos , Vigilância Imunológica/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Macrófagos/imunologia , Polímeros/farmacologia , Copolímero de Pirano/farmacologia , 2-Cloroadenosina , Adenosina/farmacologia , Adenosina/toxicidade , Animais , Anticorpos/imunologia , Reações Antígeno-Anticorpo , Neoplasias Pulmonares/secundário , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C
3.
Cancer Res ; 48(21): 6081-9, 1988 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-3048654

RESUMO

We have examined the ability of in vivo treatment of mice with recombinant interleukin 2 (rIL-2) to affect natural immunity measured against tumor (YAC-1) or virally infected (herpes simplex type 1) target cells. rIL-2 treatment leads to significant increases in natural killer/lymphocyte-activated killer (NK/LAK) function and spleen cells recovered. This effect is dose dependent and strain related. The latter parameter correlated with the pretreatment NK activity level of the strain. The rIL-2 induced NK/LAK augmentation is also kinetically restricted as treatment must have occurred within 48-72 h of assay to be effective. The rIL-2 therapy effectively enhances both antitumor and antiviral NK/LAK activity and results in a noticeable increase in asialo-GM1-positive cells in the spleens of treated mice as well as a significant increase in IL-2 receptor expression as monitored by either cytometry or radioligand binding. In vivo treatment of mice with an antibody directed to the ASGM1 determinant effectively reduces the rIL-2 augmentation of both antitumor and antiviral activity even though this treatment does not affect the pretreatment level of antiviral activity. Various natural and induced immunodeficiency states (immunotherapy, irradiation, immunosuppressive drugs, cytoreductive drugs) have been examined for the ability of in vivo treatment with rIL-2 to enhance NK/LAK activity. In vivo rIL-2 administration is differentially effective in enhancing NK/LAK activity in these situations. Notably, in these induced immunodeficiency states, although NK/LAK activity is commonly enhanced, the number of spleen cells recovered often is only marginally affected. Thus, as expected, a limiting aspect in this use of a natural immunomodulator is the number of potentially responsive cells present in the immunodeficiency condition. In addition, correlations between rIL-2 effect, several of the immunodeficiency states, and vascular leak syndrome are briefly discussed.


Assuntos
Gangliosídeo G(M1) , Síndromes de Imunodeficiência/imunologia , Interleucina-2/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Animais , Antineoplásicos/farmacologia , Relação Dose-Resposta a Droga , Feminino , Glicoesfingolipídeos/análise , Glicoesfingolipídeos/imunologia , Imunossupressores/farmacologia , Células Matadoras Naturais/imunologia , Masculino , Camundongos , Camundongos Endogâmicos , Neoplasias Experimentais/imunologia , Receptores de Interleucina-2/análise , Proteínas Recombinantes/farmacologia , Especificidade da Espécie , Viroses/imunologia , Irradiação Corporal Total
4.
Neurology ; 53(6): 1308-11, 1999 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-10522889

RESUMO

OBJECTIVE: To determine whether a specific apolipoprotein E (APOE) polymorphism is a risk factor for ischemic cerebrovascular disease (CVD; stroke or TIA). BACKGROUND: The APOE epsilon4 allele is overrepresented in AD, atherosclerosis, and ischemic heart disease. In addition, epsilon4 carriers have higher plasma cholesterol levels than non-epsilon4 carriers. METHODS: Using Medline (OVID and PubMed), a search was performed for all studies that examined APOE in ischemic CVD. The authors identified nine case-control studies that were suitable for analysis. RESULTS: There were 926 patients with ischemic stroke or TIAs and 890 age- and sex-matched control subjects. Overall analysis revealed a significantly higher APOE-epsilon4 allelic frequency in affected patients compared with control subjects (0.14 versus 0.09; odds ratio, 1.68; 95% CI, 1.36 to 2.09; p<0.001). There was a significant excess of the epsilon3 allele (0.85 versus 0.80) but not the epsilon2 allele (0.06 versus 0.06) in the control subjects compared with the ischemic CVD patients. Seven studies had data on APOE genotypes. Carriers of epsilon4 were more frequent among ischemic CVD patients than control subjects (27% versus 18%; odds ratio, 1.73; 95% CI, 1.34 to 2.23; p<0.001). CONCLUSIONS: The APOE-epsilon4 allele and carriers of epsilon4 are more frequent among patients with ischemic CVD compared with control subjects. The epsilon2 allele does not appear to be protective for ischemic CVD. These findings imply a role for the APOE genotype in the pathogenesis of some cases of ischemic CVD.


Assuntos
Apolipoproteínas E/genética , Isquemia Encefálica/genética , Transtornos Cerebrovasculares/genética , Alelos , Genótipo , Humanos , Razão de Chances , Polimorfismo Genético , Fatores de Risco
5.
Neurology ; 53(9): 2176-9, 1999 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-10599801

RESUMO

We investigated whether early hematoma or edema volumes could explain the adverse association between APOE epsilon4 and survival in intracerebral hemorrhage. Among 102 patients, epsilon4 carriers had a higher mortality rate than non-epsilon4 carriers (38 versus 24%, p = 0.05). Nonsurvivors had larger hematoma (75.5 cm3 versus 27.1 cm3, p<0.001) and edema volumes (37.5 cm3 versus 17.1 cm3, p<0.01), but these were not associated with epsilon4 after adjusting for race, age, and type of hemorrhage.


Assuntos
Apolipoproteínas E/genética , Edema Encefálico/genética , Hemorragia Cerebral/genética , Genótipo , Hematoma/genética , Idoso , Apolipoproteína E4 , Edema Encefálico/mortalidade , Hemorragia Cerebral/mortalidade , Feminino , Frequência do Gene/genética , Triagem de Portadores Genéticos , Hematoma/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Taxa de Sobrevida
6.
Int J Radiat Oncol Biol Phys ; 46(4): 947-58, 2000 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-10705017

RESUMO

PURPOSE: The objective of this study was to perform the dosimetry and evaluate the dose-response relationships in newly diagnosed patients with malignant brain tumors treated by direct injections of (131)I-labeled 81C6 monoclonal antibody (MAb) into surgically created resection cavities (SCRCs). METHODS AND MATERIALS: Absorbed doses to the 2-cm-thick shell as measured from the margins of the resection cavity interface were estimated for 42 patients with primary brain tumors. MR images were used to assess the enhanced-rim volume as a function of time after radiolabeled MAb therapy. Biopsy samples were obtained from 15 patients and 1 autopsy. RESULTS: The average absorbed dose [range] to the 2-cm shell region was 32 [3-59] Gy. For the endpoint of minimal time to MR contrast enhancement, the optimal absorbed dose and initial dose-rate were 43 +/- 16 Gy and 0. 41 +/- 0.10 Gy/h, respectively. There was a correlation between the absorbed dose and dose rate to the shell region and biopsy outcome (tumor recurrence, radionecrosis, and tumor recurrence and/or radionecrosis). In this Phase I study, the maximum tolerated dose (MTD) was 120 mCi. At this MTD, the estimated average absorbed dose and initial dose rate to the 2-cm shell were 41 [9-89] Gy and 0.51 [0.24-1.13] Gy/h, respectively. These values are in agreement with the optimal values based on the time to MR lesion rim enhancement. CONCLUSIONS: The average absorbed dose to the 2-cm shell region varied considerably and mainly depended on cavity volume. In future clinical trials, the administered activity of (131)I-labeled 81C6 MAb may be adjusted based on cavity volume in order to deliver the optimal absorbed dose of 43 Gy rather than giving a fixed administered activity.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Neoplasias Encefálicas/radioterapia , Glioma/radioterapia , Radioisótopos do Iodo/uso terapêutico , Radioimunoterapia/métodos , Tenascina/imunologia , Relação Dose-Resposta à Radiação , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
7.
J Med Chem ; 23(4): 368-72, 1980 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6247489

RESUMO

The synthesis and antirhinovirus activity of syn and anti isomers of 6-[[(hydroxyimino)phenyl]methyl]-1-[(1-methylethyl)sulfonyl]-1H-benzimidazol-2-amine (4 and 5) are reported. The structural assignments of 4 and 5 are based upon 13C NMR spectra of both isomers and also X-ray analysis of 5. The anti-isomer 5 was more potent than the syn-isomer 4 when compared as an inhibitor of rhinovirus multiplication in vitro. Both isomers inhibited multiplication of 15 different serotypes of rhinovirus.


Assuntos
Antivirais/síntese química , Benzimidazóis/síntese química , Rhinovirus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Benzimidazóis/farmacologia , Células HeLa , Humanos , Espectroscopia de Ressonância Magnética , Oximas , Estereoisomerismo , Sulfonamidas , Ensaio de Placa Viral , Cultura de Vírus , Difração de Raios X
8.
J Nucl Med ; 36(5): 883-7, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7738668

RESUMO

UNLABELLED: FDG-PET can differentiate benign from malignant focal pulmonary opacities. We performed dynamic FDG-PET studies to determine the optimum time for emission data acquisition. METHODS: Patients with focal pulmonary abnormalities demonstrated by biopsy to be malignant (n = 10) or benign (n = 4) were evaluated with dynamic FDG-PET. Dynamic PET data were acquired as sequential 5-min images for 2.5 hr. Radioactivity concentration measurements of the focal abnormality, a similar area in the opposite lung, and both lungs in the field of view were made throughout the period of acquisition. Standardized uptake ratios (SUR) of the lesions were calculated. SUR data and lesion-to-background ratios were plotted. The time that the SUR provided the maximum separation between benign and malignant masses after FDG administration was determined. RESULTS: The SUR values provided the greatest separation between benign and malignant abnormalities beginning at 50 min and no advantage was identified in imaging later. Achievement of a 4:1 lesion-to-background ratio occurred by 50 min in malignant lesions. CONCLUSION: The acquisition of the emission data used in the evaluation of pulmonary malignancy should begin approximately 50 min after FDG administration.


Assuntos
Desoxiglucose/análogos & derivados , Radioisótopos de Flúor , Neoplasias Pulmonares/diagnóstico por imagem , Tomografia Computadorizada de Emissão , Fluordesoxiglucose F18 , Humanos
9.
J Nucl Med ; 35(11): 1771-6, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7965154

RESUMO

UNLABELLED: FDG PET images of the thorax can be analyzed semiquantitatively using standardized uptake ratios (SUR) or activity ratios between abnormal and normal tissue, or qualitatively by visual comparison of the abnormality to normal structures. Standardized uptake ratio evaluation of FDG PET images has been shown to accurately differentiate benign from malignant focal pulmonary abnormalities. The accuracy of activity ratios and visual analysis have not been evaluated. We therefore prospectively analyzed FDG PET images in patients with pulmonary abnormalities to evaluate differences in analytic schemes. METHODS: We evaluated 107 patients with an indeterminate focal abnormality on chest radiograph or CT with FDG PET between November 1991 and March 1993. The PET studies were evaluated using SUR, activity ratios and visual analysis. Activity ratios of maximum activity/cc and average activity/cc between regions of interest (ROIs) in abnormalities and normal lung on the contralateral side were calculated. Visual interpretations were graded on a five-point scale of two observers' confidence of malignancy. FDG uptake in the abnormality was also visually graded in comparison to mediastinal activity. Receiver-operating characteristic (ROC) curve areas were generated for the SUR data, activity ratios and visual analysis. RESULTS: Of 88 patients in which a conclusive diagnosis was made, 61 (69%) patients had malignancy and 27 (31%) patients had a benign process. SUR, maximum activity ratio, average activity ratio and visual interpretation ROC curve areas were 0.96, 0.95, 0.92 and 0.96, respectively. CONCLUSIONS: SUR, activity ratios and visual evaluation are each equally accurate methods of FDG PET data analysis in differentiating malignant from benign focal pulmonary abnormalities.


Assuntos
Desoxiglucose/análogos & derivados , Radioisótopos de Flúor , Neoplasias Pulmonares/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Tomografia Computadorizada de Emissão , Diagnóstico Diferencial , Fluordesoxiglucose F18 , Humanos , Processamento de Imagem Assistida por Computador , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade
10.
J Nucl Med ; 36(2): 278-86, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7830132

RESUMO

UNLABELLED: This study evaluates the quantitative accuracy of SPECT for in vivo distributions of 99mTc radiopharmaceuticals using fanbeam (FB) and parallel-beam (PB) collimators and compares uniform and nonuniform attenuation correction methods in terms of quantitative accuracy. METHODS: SPECT quantification of canine myocardial radioactivity was performed followed by well counter measurements of extracted myocardial tissue samples. Transmission scans using a line source and an FB collimator were performed to generate nonuniform attenuation maps of the canine thorax. Emission scans with two energy windows were acquired. Images were reconstructed using a filtered backprojection algorithm, with a dual-window scatter subtraction combined with either no attenuation compensation or single iteration Chang attenuation compensation based on an uniform attenuation map (mu = 0.152 cm-1) or the nonuniform transmission map. RESULTS: The measured mean counts from the SPECT images were converted to radionuclide concentrations (MBq/g) using a standard source calibration and were compared with those obtained using the well counter. CONCLUSION: The experimental results demonstrate that, compared with well counter values, the in vivo distributions of 99mTc were most accurately determined in FB and PB SPECT reconstructions with nonuniform attenuation compensation, under-estimated without attenuation compensation and overestimated with uniform attenuation compensation.


Assuntos
Coração/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Animais , Cães , Miocárdio , Compostos de Sulfidrila , Agregado de Albumina Marcado com Tecnécio Tc 99m
11.
Antiviral Res ; 2(6): 339-46, 1982 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6299189

RESUMO

A significant reduction in the death rate of infant mice infected with ten 50% lethal doses (LD50) of coxsackievirus A16 was observed when they were treated 58 h after infection with two injections of guanidine at 145 mg/kg per injection. Tremors occurred at this level but disappeared after treatment was discontinued. Tremors were apparent, but less severe at 97 mg/kg per injection and did not occur at 48 mg/kg per injection. No antiviral effect could be detected at either of these levels of guanidine. When an inactive level of guanidine (97 mg/kg per injection) was combined with 1.7 mg/kg per injection of LY122771-72, LY127123, or 2-(alpha-hydroxybenzyl)benzimidazole (HBB) and 17 mg/kg per injection of 2-guanidino-benzimidazole (GB), significant activity resulted with 2-8 treatments begun 58 h after infection. The same treatment schedule using 136 mg/kg per injection of LY122771-72, 90 mg/kg per injection of LY127123, 136 mg/kg per injection of HBB and 68 mg/kg per injection of GB produced no effect. Guanidine-associated tremors were also enhanced by the addition of the substituted benzimidazoles. When guanidine was reduced to 48 mg/kg per injection, 34 mg/kg per injection of LY122771-72 was required to produce a significant reduction in the death rate and no tremors were observed.


Assuntos
Antivirais/uso terapêutico , Benzimidazóis/uso terapêutico , Infecções por Coxsackievirus/tratamento farmacológico , Guanidinas/uso terapêutico , Animais , Combinação de Medicamentos , Sinergismo Farmacológico , Enterovirus , Guanidina , Camundongos , Oximas , Relação Estrutura-Atividade , Sulfonamidas
12.
Antiviral Res ; 10(1-3): 141-9, 1988 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3232968

RESUMO

Marked synergy between the antirhinoviral effect of rHuIFN alpha and enviroxime has been observed in vitro but an attempt to demonstrate it in volunteers was unsuccessful. The sub-optimal intranasal dose of rHuIFN alpha (0.18 Mu four times daily for 4 1/4 days) used prophylactically in the trial did reduce the severity of colds induced by RV9 and 14, but the difference did not reach statistical significance and was not enhanced by the administration of enviroxime (0.28 mg six times daily for six days). The main reason for failure is thought to be the rapid removal of enviroxime from the nose when given intranasally.


Assuntos
Benzimidazóis/uso terapêutico , Resfriado Comum/terapia , Adolescente , Adulto , Benzimidazóis/administração & dosagem , Resfriado Comum/prevenção & controle , Sinergismo Farmacológico , Quimioterapia Combinada , Feminino , Humanos , Interferon Tipo I/administração & dosagem , Interferon Tipo I/uso terapêutico , Masculino , Pessoa de Meia-Idade , Oximas , Sulfonamidas
13.
Invest Radiol ; 31(6): 316-22, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8761863

RESUMO

RATIONALE AND OBJECTIVES: Functional imaging studies such as 18F-fluoro-18-labeled-deoxyglucose-positron emission tomography (18FDG-PET) are being used increasingly in the evaluation of patients with dementia. The authors evaluate inter- and intraobserver interpretation agreement in a diverse group of patients with clinically diagnosed dementia and subjective memory complaints, as well as two healthy control subjects. METHODS: Ninety-six patients with clinical diagnoses of probable Alzheimer's disease (n = 18), possible Alzheimer's disease (n = 33), dementia (n = 26), and mild memory impairment (n = 17), as well as two healthy control subjects were studied using 18FDG-PET. Three observers graded all studies for regional 18FDG uptake in the temporal, parietal, and frontal regions bilaterally. The studies also were interpreted for the presence of bilateral temporoparietal hypometabolism, which typically is present in Alzheimer's disease. The kappa statistic was used to determine intra- and interobserver agreement for regional 18FDG uptake and bilateral temporoparietal hypometabolism. RESULTS: There was excellent intraobserver (kappa = .56, P < 0.0005) and interobserver (kappa = .51, P < 0.0005) interpretation agreement for bilateral temporoparietal hypometabolism. There also was excellent intraobserver (kappa = .61, P < 0.000) and interobserver (kappa = .55, P < 0.000) interpretation agreement of regional 18FDG uptake. Interobserver agreement was extremely high in those patients who were considered clinically to have possible (kappa = .42, P < 0.001) or probable (kappa = .42, P < 0.01) Alzheimer's disease. CONCLUSIONS: Results confirm that bilateral temporoparietal hypometabolism is the metabolic abnormality associated with the diagnosis of probable Alzheimer's disease. Furthermore, intra- and interobserver agreement of visual interpretation of 18FDG-PET images indicates that 18FDG-PET is acceptable as an imaging technique in the clinical evaluation of the dementia patient.


Assuntos
Demência/diagnóstico por imagem , Desoxiglucose/análogos & derivados , Radioisótopos de Flúor , Variações Dependentes do Observador , Tomografia Computadorizada de Emissão , Adulto , Idoso , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Pessoa de Meia-Idade
14.
J Pain ; 1(4): 268-74, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-14622609

RESUMO

In this study, pain during mammography in women treated conservatively for breast cancer was examined. It studied pain intensity and its relation to a variety of demographic, medical, and pain coping variables as well as to objective measures of breast compression. Ninety-nine women, treated with lumpectomy (with or without radiation) and undergoing follow-up screening mammography, were asked about strategies they use to cope with everyday pain and then were asked to report pain experienced during the mammogram. Treated and untreated breasts were rated separately and compared with a sample of 125 control women with no history of breast cancer. Women reported significantly greater pain in the treated breast (41% greater than the untreated breast and 32% greater than the control group). There was no consistent relationship between mammography pain and pain coping. Average intensity of pain at last mammogram was the best predictor of pain in both breasts. Women treated conservatively for breast cancer experience significantly greater pain during mammography of their treated breast. Radiologists and technologists can identify women at risk for a painful mammogram by asking about the pain at last mammogram. By applying pain-reducing interventions, they might be able to make the mammography experience more tolerable for these women.

15.
J Neuroimaging ; 11(2): 141-7, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11296583

RESUMO

OBJECTIVE: Diffusion-weighted magnetic resonance imaging (DWI) detects acute ischemic infarcts with high lesion conspicuity. Determination of infarct age is difficult on DWI alone because infarct signal intensity (SIinfarct) on DWI is influenced by T2 properties ("T2 shine-through"). Maps of the apparent diffusion coefficient (ADC) reflect pure diffusion characteristics without T2 effects but have low lesion conspicuity. Thus, in clinical practice, combined use of DWI and ADC maps is required. Exponential DWI (eDWI) is an innovative means of MRI-diffusion data analysis that merges the advantages of DWI and ADC maps. The authors hypothesized that SIinfarct on eDWI would correlate with infarct age. The authors studied 114 consecutive patients who had 120 ischemic strokes with clearly determined onset times and who underwent echo-planar DWI. The eDWI were generated by dividing the signal intensity on DWI by that on the corresponding T2 image on a pixel-by-pixel basis. SIinfarct on eDWI was measured in the lesion core and expressed as a percentage of contralateral control tissue. On eDWI, relative SIinfarct changed significantly with infarct age (P < .0001). When patients were sorted in infarct-age groups, no significant differences were found within the first 120 hours. However, for patients studied within 5 days, the mean relative SIinfarct was significantly higher compared with patients studied > or = 8 days after stroke (P < .05). For all infarcts up to 5 days old, the eDWI signal intensity was higher than control tissue (hyperintense appearance). All infarcts > 10 days old had an eDWI signal intensity lower than control tissue (hypointense appearance). The authors concluded that the use of eDWI, as a single set of images, reliably differentiates acute infarcts (< or = 5 days old) from infarcts > 10 days old. This feature would be expected to be helpful when the distinction between acute and nonacute infarction cannot be determined on clinical grounds.


Assuntos
Infarto Cerebral/diagnóstico , Aumento da Imagem , Imageamento por Ressonância Magnética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Difusão , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
16.
Acad Radiol ; 3(3): 254-9, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8796673

RESUMO

RATIONALE AND OBJECTIVES: To control costs, it is increasingly important to make efficient use of imaging technology. We sought to determine and analyze the time required to complete each step of a body computed tomography (CT) scan, focusing on factors that influence patient throughput. METHODS: Over 4 weeks, we prospectively monitored the time required for each step of a body CT scan (i.e., image time, check time, and clear time). Covariate data were collected by patient status: outpatient, inpatient, emergency department (ED), and intensive care unit (ICU); work shift; and radiologist training level (junior resident, senior resident, fellow, and attending). Technologists also predicted whether repeat images would be requested by the radiologist. RESULTS: Three hundred eighty CT examinations were studied: 277 for outpatients, 90 for inpatients, 9 for ED patients, and 4 for ICU patients. The mean total examination time was 44.7 min (mean image time = 33.1 min, mean review time = 8.2 min, and mean clear time = 3.4 min), which did not differ significantly with patient status. A second opinion was sought from a consultant radiologist on the scans of 44 patients. Consultation was requested significantly more frequently (1) by junior residents than by senior residents or fellows and (2) for ED and ICU patients (22% and 50%, respectively) than in outpatients and inpatients (10% and 14%, respectively). Repeat images were obtained from 75 patients, and this was not significantly related to patient status, scan type, or radiologist training level. When the technologist predicted that no repeat images were needed, this prediction agreed with the radiologist in 86% of the cases. When the technologist predicted that repeat images were necessary, this prediction agreed with the radiologist in 56% of the cases. CONCLUSION: Reviewing scans before the patient leaves the CT suite adds considerably to the total time required to complete a scan, particularly if junior residents review scans. If technologists obtain repeat images at their discretion, time would be saved.


Assuntos
Hospitais de Ensino , Serviço Hospitalar de Radiologia/organização & administração , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Humanos , Estudos Prospectivos , Garantia da Qualidade dos Cuidados de Saúde , Análise e Desempenho de Tarefas , Fatores de Tempo , Tomografia Computadorizada por Raios X/normas
17.
J Thorac Imaging ; 10(1): 59-72, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7891398

RESUMO

We compared the conspicuity of acute pulmonary emboli with contrast-enhanced spiral computed tomography (CT) and two- and three-dimensional time-of-flight magnetic resonance (MR) techniques. Seven dogs who received experimental pulmonary emboli and one control were imaged with spiral CT and with 2-D (FMPVAS and FASTCARD) and 3-D time-of-flight MR. Blinded, independent, prospective evaluations of the CT and MR images by two MR radiologists and two chest radiologists were then compared to the location of the emboli as determined by subsequent pathologic evaluation of the excised lungs. Embolus/blood contrast-to-noise ratios (CNRs) were calculated on both MR and CT images for pulmonary emboli that could be identified. Fifty emboli ranging from 1.0 to 5.5 mm (mean, 2.7, +/- 0.14 SEM) in diameter and from 3.0 to 60 mm (mean, 28.1 +/- 1.9 SEM) in length were found in the seven embolized dogs on pathologic examination. Three of the four radiologists identified more thrombi on CT images than they did on their best MR pulse sequence (FASTCARD) and with greater confidence. The fourth radiologist identified an equal percentage of clot on CT and FASTCARD images with confidence slightly greater on FASTCARD MR than on spiral CT. Mean CNR for the best MR technique was 43.4 (+/- 3.9 SEM) and for CT was 20.7 (+/- 1.3 SEM). In general, pulmonary emboli were detected more accurately on contrast-enhanced spiral CT than on MR. This occurred although the embolus/blood CNR was higher on MR than on CT. Better pulmonary embolus conspicuity on CT images was attributed to better spatial resolution and fewer artifacts on CT than on MR. One MR radiologist performed equally well with both spiral CT and FASTCARD techniques, suggesting that experience may be a factor in performance.


Assuntos
Imageamento por Ressonância Magnética , Embolia Pulmonar/diagnóstico , Tomografia Computadorizada por Raios X , Animais , Cães , Feminino , Variações Dependentes do Observador , Estudos Prospectivos , Embolia Pulmonar/diagnóstico por imagem , Método Simples-Cego
18.
Clin Imaging ; 23(6): 347-52, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10899415

RESUMO

The purpose of this study was to evaluate the stereotactic 14-gauge, vacuum-assisted biopsy technique in diagnosing noncalcified breast lesions. Stereotactic biopsy of 116 noncalcified breast lesions was performed with either 14-gauge, vacuum-assisted technique or multipass, automated large-core technique. The number of core samples and time required for each biopsy were compared. Outcome for each technique was compared based on recommendations after the mammographic-histologic review process. Results from surgical excision and mammographic follow-up were reviewed. The vacuum-assisted technique obtained more tissue cores per lesion than the automated gun technique, showed marginal decrease in number of repeat biopsies for discordant results, and required fewer short-term follow-up mammograms, although the difference did not achieve statistical significance. The vacuum-assisted technique can be used successfully to sample noncalcified breast masses, with marginal improvement over the automated gun technique.


Assuntos
Biópsia por Agulha/métodos , Neoplasias da Mama/patologia , Adulto , Idoso , Biópsia por Agulha/instrumentação , Neoplasias da Mama/diagnóstico por imagem , Calcinose/patologia , Distribuição de Qui-Quadrado , Feminino , Humanos , Mamografia/métodos , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Estatísticas não Paramétricas , Técnicas Estereotáxicas , Vácuo
19.
Lab Anim (NY) ; 30(4): 23-6, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11385741

RESUMO

An effective occupational health and safety program is critical to ensure personnel safety in working with animals. The authors present data compiled from AAALAC international site visits conducted between 1993 and 1999, which indicate how programs can fall short of current recommendations.


Assuntos
Técnicos em Manejo de Animais , Animais de Laboratório , Fidelidade a Diretrizes , Saúde Ocupacional , Animais , Humanos , Higiene , Cooperação Internacional , Política Organizacional , Equipamentos de Proteção , Medição de Risco , Desenvolvimento de Pessoal
20.
AORN J ; 54(4): 831-6, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1952907

RESUMO

The current approach to QA primarily involves taking action when problems are discovered and designing a documentation system that records the deliverance of quality care. Involving the entire staff helps eliminate problems before they occur. By keeping abreast of current problems and soliciting input from staff members, the QA at our hospital has improved dramatically. The cross-referencing of JCAHO and AORN standards on the assessment form and the single-sheet reporting form expedite the evaluation process and simplify record keeping. The bulletin board increases staff members' understanding of QA and boosts morale and participation. A sound and effective QA program does not require reorganizing an entire department, nor should it invoke negative connotations. Developing an effective QA program merely requires rethinking current processes. The program must meet the department's specific needs, and although many departments concentrate on documentation, auditing charts does not give a complete picture of the quality of care delivered. The QA committee must employ a variety of data collection methods on multiple indicators to ensure an accurate representation of the care delivered, and they must not overlook any issues that directly affect patient outcomes.


Assuntos
Comitê de Profissionais/organização & administração , Garantia da Qualidade dos Cuidados de Saúde/organização & administração , Centro Cirúrgico Hospitalar/normas , Controle de Formulários e Registros , Humanos , Joint Commission on Accreditation of Healthcare Organizations , Prontuários Médicos , Enfermagem de Centro Cirúrgico/normas , Objetivos Organizacionais , Técnicas de Planejamento , Sociedades de Enfermagem , Centro Cirúrgico Hospitalar/organização & administração
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA