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J Primavera

Publications and source records attributed to J Primavera.

8 recordsLinked to original sources
PubMed2001

Diffusion MRI in ischemic stroke compared to pathologically verified infarction.

BACKGROUND: Diffusion MRI abnormality correlates with pathology in animal ischemic stroke models. A combined retrospective and prospective analysis of consecutive patients over a 3-year period who had a clinical diagnosis of probable new ischemic stroke, underwent diffusion MRI, and were later studied at autopsy was performed. METHODS: Inclusion criteria for the retrospective analysis were 1) symptom onset within 14 days of presentation, 2) diffusion MRI within 28 days of symptom onset, and 3) autopsy within 16 weeks of symptom onset. Patients with suspected further infarcts between MRI and autopsy were excluded. The locations of all areas of MRI abnormality were identified by a blinded neuroradiologist, and recent infarcts were identified by review of pathologic records and microscopic slides. RESULTS: Eleven patients were identified who fulfilled inclusion criteria, with 25 discrete pathologic infarcts. Diffusion MRI abnormality corresponded to pathologically verified infarction in 23 cases, was present in two locations where no pathologic infarct was identified, and was absent in two locations where an infarct was present at autopsy. In two cases, despite clinical suspicion of acute ischemic stroke, no MRI abnormality or pathologic infarct was found. The sensitivity and specificity of diffusion MRI were 88.5% (95% CI, 69.9% to 97.6%) and 96.6% (95% CI, 91.5% to 99.1%). Accuracy was 95.1% (95% CI, 90.2% to 98%). Three further patients who died during the course of the retrospective analysis were studied prospectively, and are described separately. CONCLUSIONS: These findings suggest high accuracy of diffusion MRI for detection of ischemic infarction compared with pathologic examination.

Adult↗
PubMed2001

Clear cell pleomorphic xanthoastrocytoma: case report.

Pleomorphic xanthoastrocytoma (PXA) is a well-described astrocytic neoplasm with distinctive clinical and pathological features. Although most patients with PXAs are cured by surgical excision, other patients experience malignant progression and tumor recurrence. We describe a 47-year-old woman with a left temporal lobe PXA that had classic histopathological characteristics as well as extensive clear cell and focal papillary changes, and some anaplastic findings. The patient has now suffered two recurrences after complete resection. The case illustrates a rare, previously undescribed histological variant of PXA, with a prominent clear cell and focal papillary morphology. The study of histologically similar cases is needed to determine whether this variant is always associated with a greater likelihood of recurrence.

Astrocytoma↗
PubMed1998

Endothelial dysfunction and the expression of endothelial nitric oxide synthetase in diabetic neuropathy, vascular disease, and foot ulceration.

We studied endothelial-mediated microvascular blood flow in neuropathic diabetic patients to determine the association between endothelial regulation of the microcirculation and the expression of endothelial constitutive nitric oxide synthetase (ecNOS) in the skin. Vasodilation on the dorsal foot in response to heating and iontophoresis of acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) were measured using single-point laser Doppler and laser Doppler imaging in diabetic patients with neuropathy (DN), with neuropathy and vascular disease (DI), with Charcot arthropathy (DA), and without complications (D), and in healthy control subjects (C). The response to heat was reduced in the DN (321 [21-629] percentage of increase over the baseline, median [interquartile range]) and DI (225 [122-470]) groups but was preserved in the DA (895 [359-1,229]), D (699 [466-1,029]), and C (810 [440-1,064], P < 0.0001) groups. The endothelial-mediated response to acetylcholine was reduced in the DN (17 [11-25]), DA (22 [2-34]), and DI (13 [2-30]) groups compared with the D (47 [24-58]) and C (44 [31-70], P < 0.001) groups. The non-endothelial-mediated response to sodium nitroprusside was also reduced in the DI (4 [0-18]), DN (17 [9-26]), and DA (21 [11-31]) groups compared with the D (37 [19-41]) and C (44 [26-67], P < 0.0001) groups. There was a significant reduction in vasodilation in the DI group compared with all other groups (P < 0.0001). Full thickness skin biopsies from the dorsum of the foot of 15 DN, 10 DI, and 11 C study subjects were immunostained with antiserum to human ecNOS, the functional endothelial marker GLUT1, and the anatomical endothelial marker von Willebrand factor. The staining intensity of ecNOS was reduced in both diabetic groups. No differences were found among the three groups in the staining intensity of von Willebrand factor and GLUT1. We conclude that the endothelium-dependent and endothelium-independent vasodilations are impaired in diabetic patients predisposed to foot ulceration and that neuropathy is the main factor associated with this abnormality. Reduced expression of ecNOS may be a major contributing factor for endothelial dysfunction. These data provide support for a close association of neuropathy and microcirculation in the pathogenesis of foot ulceration.

Acetylcholine↗
PubMed1985

Parental separation/divorce and adolescents: an examination of factors mediating adaptation.

This study examined the relationship between differences in current adjustment as they related to a number of demographic, personal, and situational factors for 65 late adolescents/young adults who had experienced this life transition. Utilizing multiple regression analyses, several factors emerged as particularly salient mediators of the adolescents' postdivorce adjustment, including distance from home, coping style, family cohesion, conflict and organization, and the use of family members for support. The importance of clarifying the role of psychological and situational mediating factors in order to understand the consequences of parental divorce and to organize preventive and ameliorative efforts for this population is discussed.

Adaptation, Psychological↗
PubMed1985

Adaptation and vulnerability in high-risk adolescents: an examination of environmental mediators.

The relationship of characteristics of the social environment to the adaptation of adolescents from high-risk predisposing environments was examined. Specifically, the degree to which adolescents' perceptions of various dimensions of their family and school environment as well as sources of social support related to differential levels of personal well-being and academic adjustment was explored. Multiple regression analyses revealed differences in the salience of the dimensions of the social environment as a function of the particular sphere of functioning under consideration. Implications of the findings for developing a model for understanding the relative vulnerability of individuals at risk as well as of the design of preventive interventions are discussed.

Achievement↗
PubMed1982

Social support in high-risk adolescents: structural components and adaptive impact.

This study examines the structure of social support and its relationship to adjustment for adolescents from high-stress lower socioeconomic class inner-city backgrounds. An attempt is made to (a) identify meaningful dimensions of perceived social support for this population; (b) examine the degree to which the perceived helpfulness of each source of support varied as a function of age, sex, and ethnic background; and (c) determine the relationship between the dimensions of social support, personal characteristics of the adolescent, and indices of personal and academic adjustment. Factor analyses reveal three distinct support dimensions: Family, Formal, and Informal Support. Multivariate and univariate analyses of variance show differences in the perceived helpfulness of the support dimensions as a function of the adolescent's age, sex, and ethnic background as well as in the relationship of each source of support to the adjustment indices. Implications of the findings for elaborating the impact of social support on coping efforts are discussed.

Achievement↗
PubMed1982

Primary prevention during school transitions: social support and environmental structure.

The nature and evaluation of a primary prevention project for students during the transition to high school are presented. In order to facilitate students' coping efforts during this transition, the project sought to increase the level of social support available as well as to reduce the degree of flux and complexity in the school setting. Midyear and end of ninth-grade assessments were done of Project and matched Control students' self-concepts. Their perceptions of the school environment, and their eighth- and ninth-grade attendance and grade averages examined. By the end of ninth grade, Project participants showed significantly better attendance records and grade point averages as well as more stable self-concepts than controls. Further, by the final evaluation point, Project students also reported perceiving the school environment as having greater clarity of expectations and organizational structure and higher levels of teacher support and involvement than did nonproject Controls.

Achievement↗