Biomedical subjects

D O Stram

Publications and source records attributed to D O Stram.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Analysing repeated measurements with possibly missing observations by modelling marginal distributions.

Suppose that subjects are observed repeatedly over a common set of time points with possibly time-dependent covariates and possibly missing observations. At each time point we model the marginal distribution of the response variable and the effect of the covariates on that distribution using a class of quasi-likelihood models studied in McCullagh and Nelder. No parametric model of dependence of the repeated observations of the subject is assumed. For large samples, the quasi-likelihood estimates of the time-specific regression coefficients over the set of predetermined time points are shown to be approximately jointly normal. This, coupled with various inference procedures, provides a global picture about the effects of the covariates on the response variable over the entire study period. A lack-of-fit test for testing the adequacy of the assumed quasi-likelihood model is also provided. All the methods considered here are illustrated with real-life examples.

Air Pollution↗

PubMedDate not supplied

Metastatic sites in stage IV and IVS neuroblastoma correlate with age, tumor biology, and survival.

PURPOSE: The goal of this study was to determine the incidence of metastatic sites in neuroblastoma and the extent to which metastatic sites correlate with age, tumor biology, and survival. PATIENTS AND METHODS: All 648 patients with stage IV and IVS neuroblastoma registered on Children's Cancer Group protocols 3881 and 3891 were analyzed. Metastatic site data were provided by treating institutions and reviewed in patients with central nervous system (CNS), intracranial, lung, or "other" metastases. RESULTS: The incidence of metastatic sites at diagnosis was 70.5% in bone marrow, 55.7% in bone, 30.9% in lymph nodes, 29.6% in liver, 18.2% in intracranial and orbital sites, 3.3% in lung, and 0.6% in CNS. Event-free survival (EFS) was decreased in patients with bone, bone marrow, CNS, intracranial/ orbital, lung, and pleural metastases, and improved in those with liver and skin metastases. In infants, MYCN amplification and unfavorable Shimada histopathology correlated with increased frequencies of bone and intracranial or orbital metastases. In older patients, MYCN amplification correlated with increased frequencies of intracranial or orbital, liver, and lung metastases. Multivariate analysis revealed that metastatic site is not an independent prognostic factor. CONCLUSIONS: Metastatic pattern in neuroblastoma differs with age and correlates with tumor biological features and EFS. These correlations could reflect changes in host or tumor biological features with age resulting in differences in metastatic capacity or tumor affinity for specific sites.

Adolescent↗

PubMedDate not supplied

Antineuronal antibodies in patients with neuroblastoma and paraneoplastic opsoclonus-myoclonus.

PURPOSE: To identify serologic markers in children with paraneoplastic opsoclonus-myoclonus (POM). MATERIALS AND METHODS: We examined the sera of 64 children with neuroblastoma (16 with POM and 48 age-matched and stage-matched controls) by immunohistochemistry of rat brain and human cerebellum, and by Western blot analysis of protein extracts from human Purkinje cells, cortical neurons, neuroblastoma cell lines, and HuD. RESULTS: Using immunohistochemistry, IgG reactivity against neurons was identified in 13 of 16 POM sera (81%), and 12 of 48 non-POM sera (25%; P<0.001). IgM antineural antibodies were present in 3 of 16 POM sera (19%) and 11 of 48 (23%) non-POM sera. Except for anti-Hu antibodies detected in 10 sera (4 with POM), no other specific reactivities were identified by Western blot analysis of neuronal or of neuroblastoma protein extracts. CONCLUSIONS: We conclude that: 1) patients with neuroblastoma and POM are more likely to harbor antineuronal antibodies than patients without POM; 2) no specific serologic marker of POM was identified, but the frequent presence of antineuronal antibodies suggests that POM is immune-mediated; and 3) anti-Hu antibodies are present in some sera from patients with neuroblastoma, irrespective of the presence of POM.

Adult↗