Our objective in this study was to identify histologically homogenous classes of childhood supratentorial neuroglial tumors. Previously, we identified five quantitative histologic factors (differing linear combinations of 17 reliably recognized histologic features in neuroglial tumors). They account for much of the histologic variance in the 703 supratentorial tumors in the Childhood Brain Tumor Consortium (CBTC) database. In this study, we used the scores on the factors in cluster analyses and identified eight classes of neuroglial tumors. Each of these classes had significant differences in histology, allowing the separation of many of the conventional types of neuroglial tumors into two or more classes. For instance, fibrillary astrocytoma, pilocytic astrocytoma, subependymal giant cell astrocytoma, anaplastic astrocytoma, oligodendroglioma, and ependymoma were represented in two or more classes. Often these classes had statistically significant differences in survival distributions. For instance, the two classes of "anaplastic astrocytomas" have widely discrepant 5-year survival probabilities of 0.7 and 0.2. Use of the classes identified in this study ensures relatively homogeneous histologic subsets of tumors. We suggest that these classes will be useful for the selection of children for therapeutic clinical trials.

Astrocytoma↗

PubMedDate not supplied

Effect of Fluosol on oxygen availability, regional cerebral blood flow, and infarct size in a model of temporary focal cerebral ischemia.

Twenty-four cats had an intravenous infusion of either Fluosol or saline and then were subjected to 2 hours of middle cerebral artery occlusion. All the animals infused with Fluosol and one-half the animals infused with saline were ventilated with 100% O2. Tissue oxygen availability and regional cerebral blood flow were measured by platinum electrodes using direct voltage recordings for oxygen measurements and hydrogen clearance curves for measurements of cerebral blood flow. With 100% oxygenation tissue oxygen availability increased significantly in the Fluosol treated animals, however, during the time of ischemia oxygen availability decreased below baseline values to about an equal level whether the animals were treated with Fluosol or saline. Regional cerebral blood flow fell to a similar value in all groups during the time of occlusion. One hour after reperfusion blood flow increased considerably above baseline values in all groups and oxygen availability also increased in all groups but particularly in the Fluosol treated animals. Overall mortality and the size of infarction 1 week after the ischemic insult were not significantly different in the three groups. Mortality was directly related to the size of the infarct which, in turn, was related to the degree of ischemia during the time of occlusion.

Animals↗

PubMedDate not supplied

Reassessment of cerebral capillary changes in acute global ischemia and their relationship to the "no-reflow phenomenon".

Electron and light microscopic studies were performed on rabbit brain to re-examine the structural changes of endothelial cells and perivascular glia following ischemia. Although swelling of perivascular glia occurred, earlier findings of extreme perivascular glial swelling and bleb formation leading to luminal collapse and plugging could not be confirmed. Ischemic brains, however, had a higher proportion of small-diameter capillaries than controls. It is felt that structural changes in ischemic capillary walls in themselves are not sufficient to explain failed cerebral reperfusion, or the no-reflow phenomenon.

Animals↗

PubMedDate not supplied

Quantitative histologic factors for grouping childhood supratentorial neuroglial tumors.

The histologic heterogeneity of childhood supratentorial neuroglial tumors, when quantified, identifies relatively homogeneous subgroups for prognostic purposes and for assignment in clinical trials. Our sample consisted of supratentorial tumors in the Childhood Brain Tumor Consortium. The data consist of reliably identified histologic features and demographic, clinical, operative, and survival information. Factor analysis was used to identify uncorrelated "factors," each represented by a different combination of histologic features in 703 tumors. The defining histologic features were used to label each factor. The heterogeneity of each tumor was summarized using the factor scores for each factor. We compared the survival estimates of subgroups of tumors within common diagnostic classes. We identified five uncorrelated quantitative factors that accounted for much of the histologic variation. Our factor labels were Jumbo, Fibrillary, Proliferative, Spongy, an Oligodendroglial. Two thirds of tumors had high scores on two or more factors, indicating a high degree of heterogeneity among these tumors. Eighty-four percent of supratentorial tumors were accounted for by 19 nonoverlapping relatively homogeneous histologic groups. The five quantitative factors complement standard qualitative taxonomies by summarizing more completely the histologic feature aspects of a tumor than by diagnosis alone and quantify the histologic heterogeneity of individual tumors. Histologically homogeneous groups of tumors are essential for clinical trials, biologic research, and prognostic models.

Adolescent↗

PubMedDate not supplied

Prognosis for children with supratentorial neuroglial tumors.

Factor analysis of reliably identified histologic features in supratentorial glial tumors yielded five interpretable "factors": Spongy, Fibrillary, Proliferative, Jumbo, and Oligodendroglial. Quantitative scores can be calculated for each factor in a tumor to summarize its heterogeneity. The objective was to investigate whether factor scores are useful for prognostic purposes. The sample consisted of 703 children with supratentorial neuroglial tumors with factor scores for each of the five factors. Data were based on the presence or absence of 26 reliably identified histologic features, plus clinical and survival information. Multivariate proportional hazards models assessed each factor's contribution to survival for children who survived 1 month after operation (n = 609). Patient-specific clinical data were allowed in the models. Increased likelihood of survival is associated with greater tumor removal, later decade of surgery, and high Spongy and high Oligodendroglial factor scores. Decreased likelihood of survival is associated with high Proliferative factor scores and radiation and/or chemotherapy treatment. Gender, age, location, and Jumbo and Fibrillary factor scores did not provide additional prognostic information. Three reliable histologic features, nondefining for any histologic factor, added prognostic information: Rosenthal fibers and glomeruli are associated with improved prognosis; pleomorphic nuclei are associated with worse prognosis. A high Oligodendroglial factor score is associated with a worse prognosis for some classes of astrocytoma but with a better prognosis for oligodendroglial tumors. A high Proliferative score is associated with a worse prognosis for anaplastic astrocytomas, ependymomas, and unclassifiable tumors. A high Spongy score is associated with a better prognosis for anaplastic astrocytomas but with a worse prognosis for pilocytic astrocytomas. For giant cell astrocytomas, gangliogliomas, and miscellaneous tumors, none of the factors is prognostic. Spongy, Oligodendroglial, and Proliferative factors provide important prognostic information for children with supratentorial neuroglial tumors.

Adolescent↗

PubMedDate not supplied

Quantitative histologic factors for grouping childhood infratentorial neuroglial tumors.

We employed factors analysis to quantify the degree of histologic heterogeneity of childhood infratentorial neuroglial tumors. Our data were 26 reliably ascertained histologic features in 1068 children in the Childhood Brain Tumor Consortium database. The factor analysis identified five uncorrelated quantitative "factors," each derived from a different linear combination of the 26 histologic features, that accounted for much of the histologic variation. Histologic features differed in their importance in each factor. The most important features in each factor were used for naming using simple, histologic, familiar descriptive terms: Spongy, Proliferative, Ring, Fibrillary, and Nuclear. Each tumor has a score on each factor. Two-thirds of tumors had high scores for at least two factors, indicating frequent histologic heterogeneity among these tumors. Ninety-five percent of tumors were allocated to 1 of 11 nonoverlapping histologically homogeneous groups. The five quantitative factors complement standard qualitative taxonomies by making explicit the histologic heterogeneity or homogeneity of individual tumors and provide the pathologist with a method that takes advantage of more of the histology of each tumor than conventional nomenclatures. Histologically homogeneous groups of tumors are likely to be of value in clinical trials and biologic research. Prognostic models based on these factors have been published.

Adolescent↗