Arterial distensibility in children and teenagers: normal evolution and the effect of childhood vasculitis

Background: Polyarteritis nodosa is a necrotising vasculitis of the medium sized and small muscular arteries. The inflammatory and subsequent reparative processes may alter the arterial mechanical properties. The effect of vasculitic damage on arterial distensibility has never been explored however. Aim: To determine the normal values and the effect of childhood vasculitis on arterial distensibility in children and teenagers. Methods: Distensibility of the brachioradial arterial segment was studied using pulse wave velocity (PWV ∝1/√distensibility), in 13 children with polyarteritis nodosa at a median age of 11.8 (range 4.9–16) years. As a control group, 155 healthy schoolchildren (6–18 years, 81 boys) were studied. PWV was assessed using a photoplethysmographic technique; blood pressure was measured by an automatic sphygmomanometer (Dinamap). Data from patients were expressed as z scores adjusted for age and compared to a population mean of 0 by a single sample t test. Determinants of PWV in normal children were assessed by univariate and multivariate linear regression analyses. Results: Age, height, weight, and systolic blood pressure correlated individually with the brachioradial PWV. Multivariate analysis identified age as the only independent determinant. Ten of the patients were in clinical remission, while three had evidence of disease activity at the time of study. The PWV in the patient group as a whole was significantly greater than those in healthy children (mean z score +0.99). Raised C reactive protein concentration (>2 mg/dl) in the three patients with active disease was associated with a higher PWV when compared to those in remission (z score +2.78 v +0.45). The diastolic blood pressure of the patients was higher than those of the controls (z score +1.04) while the systolic pressure was similar (z score -0.36). Conclusions: PWV in the brachioradial arterial segment increases gradually during childhood independent of body weight, height, mass, and blood pressure. Increased PWV, and hence decreased distensibility, in this peripheral arterial segment occurs in polyarteritis nodosa and is amplified during acute inflammatory exacerbation.     

Bullying behaviors among US youth: prevalence and association with psychosocial adjustment

CONTEXT: Although violence among US youth is a current major concern, bullying is infrequently addressed and no national data on the prevalence of bullying are available. OBJECTIVES: To measure the prevalence of bullying behaviors among US youth and to determine the association of bullying and being bullied with indicators of psychosocial adjustment, including problem behavior, school adjustment, social/emotional adjustment, and parenting. DESIGN, SETTING, AND PARTICIPANTS: Analysis of data from a representative sample of 15 686 students in grades 6 through 10 in public and private schools throughout the United States who completed the World Health Organization's Health Behaviour in School-aged Children survey during the spring of 1998. MAIN OUTCOME MEASURE: Self-report of involvement in bullying and being bullied by others. RESULTS: A total of 29.9% of the sample reported moderate or frequent involvement in bullying, as a bully (13.0%), one who was bullied (10.6%), or both (6.3%). Males were more likely than females to be both perpetrators and targets of bullying. The frequency of bullying was higher among 6th- through 8th-grade students than among 9th- and 10th-grade students. Perpetrating and experiencing bullying were associated with poorer psychosocial adjustment (P<.001); however, different patterns of association occurred among bullies, those bullied, and those who both bullied others and were bullied themselves. CONCLUSIONS: The prevalence of bullying among US youth is substantial. Given the concurrent behavioral and emotional difficulties associated with bullying, as well as the potential long-term negative outcomes for these youth, the issue of bullying merits serious attention, both for future research and preventive intervention.     

Primary retroperitoneal myxoid/round cell liposarcoma is a nonexisting disease: an immunohistochemical and molecular biological analysis

Almost all primary retroperitoneal liposarcomas can be classified as well-/dedifferentiated liposarcoma. Rarely, however, primary retroperitoneal liposarcoma is classified as myxoid/round cell liposarcoma, based on the presence of myxoid areas and vascular crow's feet pattern, which has resulted in a debate on the classification of liposarcoma in the retroperitoneum. Genetically, myxoid/round cell liposarcoma and well-/dedifferentiated liposarcoma are different diseases. Myxoid/round cell liposarcoma is characterized by a translocation causing FUS-CHOP or EWSR1-CHOP fusion, whereas well-/dedifferentiated liposarcoma is characterized by an amplification of the 12q13-15 region, including MDM2 and CDK4 genes. As myxoid/round cell liposarcoma is highly radio- and chemosensitive, differentiation between subtypes is important to optimize treatment. We studied whether primary retroperitoneal liposarcomas diagnosed as myxoid/round cell liposarcoma represent molecularly true myxoid/round cell liposarcoma or are histopathological mimics and represent well-/dedifferentiated liposarcoma. Primary retroperitoneal myxoid/round cell liposarcoma (n=16) were compared to primary extremity myxoid/round cell liposarcoma (n=20). Histopathological and immunohistochemical features were studied. Amplification status of the 12q13-15 region was studied using a multiplex ligation-dependent probe amplification analysis, and FUS-CHOP or EWS-CHOP translocations were studied using RT-PCR. In primary retroperitoneal myxoid/round cell liposarcoma, MDM2 and CDK4 staining was both positive in 12 of 15 cases. In primary extremity myxoid/round cell liposarcoma, MDM2 was negative in 18/20 and CDK4 was negative in all cases. Multiplex ligation-dependent probe amplification showed the amplification of 12q13-15 region in 16/16 primary retroperitoneal myxoid/round cell liposarcomas and in 1/20 primary extremity myxoid/round cell liposarcomas. Translocation was present in all (18/18) primary extremity myxoid/round cell liposarcomas, but absent in all primary retroperitoneal myxoid/round cell liposarcomas. On the basis of immunohistochemical and molecular characteristics, apparent primary retroperitoneal myxoid/round cell liposarcoma can be recognized as well-/dedifferentiated liposarcoma with morphological features mimicking myxoid/round cell liposarcoma. In these cases, treatment should probably be specifically designed as for well-/dedifferentiated liposarcoma. Moreover, finding of myxoid/round cell liposarcoma translocations in a retroperitoneal localization is highly suggestive of metastasis and should prompt search for a primary localization outside the retroperitoneum.     

B-cell lymphoproliferative disorders in children after bone marrow transplantation: radiologic manifestations

The radiographic findings in five pediatric patients in whom unregulated B-cell lymphoproliferative disorders developed following bone marrow transplantation are described. Four patients received T-cell-depleted bone marrow from mismatched donors and one received nondepleted marrow from a matched sibling donor. These disorders are similar to B-cell lymphoproliferative disorders that have been described in other immunosuppressed hosts. They are associated with Epstein-Barr virus and range from polyclonal proliferation without cytogenetic abnormalities to monoclonal lymphoma with clonal cytogenetic changes. Unlike other postallograft lymphoproliferative processes, B-cell lymphoproliferative disorders in these patients have not responded to antiviral therapy, immunologic therapy, or chemotherapy. The radiographic patterns of disease include diffuse or focal hepatic involvement; gallbladder wall thickening; and pulmonary, soft-tissue, and basal-ganglion masses. These radiologic findings are not specific and evaluation of tissue histology is required for diagnosis.     

苦楝化学成份的研究

从苦楝(Melia azedarach L.)果中分得苦楝新醇(Ⅰ),苦楝醇(Ⅱ)、苦楝酮(Ⅲ)、苦楝二醇(Ⅳ)、香草醛(Ⅴ)和香草酸(Ⅵ)。根据波谱(IR,MS,¹HNMR,¹³CNMR)分析和理化常数测定,确定了它们的结构。其中苦楝新醇(Ⅰ)为新化合物,对菜青小虫有一定的拒食活性。