Biomedical subjects

C J Hayostek

Publications and source records attributed to C J Hayostek.

4 recordsLinked to original sources

PubMed1999

Cellular proliferation in pilocytic and diffuse astrocytomas.

Using quantitative image analysis, we evaluated the MIB-1 labeling index (LI) in a large population of pilocytic (n = 131) and diffuse astrocytomas (n = 140), explored its significance as a prognostic predictor of survival, and compared it to other commonly accepted predictors, including grade and its histologic determinants, atypia, mitoses, endothelial proliferation, and necrosis. Diffuse astrocytomas were graded according to the St Anne-Mayo scheme and included 45 grade 2, 50 grade 3, and 45 grade 4 astrocytomas. In pilocytic astrocytomas, mean, median, and range of MIB-1 LIs were 1.1, 0.9, and 0-3.9%, respectively. In diffuse astrocytomas, these values were 2.3, 2, and 0-7.6% in grade 2; 6, 4.4, and 0.1-25.7% in grade 3; 9.1, 6, and 0.3-36% in grade 4. There was a significant difference in the distribution of MIB-1 LIs between pilocytic and diffuse grade 2 astrocytomas (p < 0.001), between grade 2 and grade 3 (p < 0.001), and between tumors of grade 3 and 4 (p = 0.014). Among pilocytic astrocytomas there was no association between survival and MIB-1 LI or any histologic parameter. In diffuse astrocytomas, MIB-1 LI was significantly correlated with grade as well as with mitotic activity (<0.001) and survival. While in diffuse astrocytomas of all grades, necrosis was the strongest factor associated with survival, in tumors of grades 2 and 3 the MIB-1 LI preceded other histologic parameters and, on multivariate analysis, remained the only feature predictive of survival. Grade 3 astrocytomas with a single "solitary" mitosis had a significantly lower MIB-I LI than did grade 3 tumors with >1 mitosis and, compared to the latter, had a significantly longer survival (p = 0.013), one not significantly different from patients with grade 2 astrocytomas. These findings suggest that the cutoff point between grade 2 and 3 in the St. Anne-Mayo scheme may not be optimal and may need to be revised.

Adolescent↗

PubMed1994

The significance of atypia and histologic malignancy in pilocytic astrocytoma of the cerebellum: a clinicopathologic and flow cytometric study.

Biologically malignant pilocytic astrocytomas are rare. Precise morphologic criteria permitting their identification and clinically meaningful distinction from more ordinary pilocytic astrocytomas have not been developed. The histologic grading schemes applied to fibrillary astrocytomas--ones based on nuclear atypia, increased cellularity, mitotic activity, endothelial proliferation, and necrosis--are thought not to correlate with prognosis in pilocytic astrocytomas. Nonetheless, these features were systematically sought in 107 cerebellar pilocytic astrocytomas, four of which were histologically malignant. The clinical, morphologic, and flow cytometric features of these cases were studied. The incidence of histologic malignancy occurring spontaneously in otherwise typical pilocytic astrocytomas was 0.9%; that occurring after radiation was 1.8%. The four histologically malignant tumors occurred in two males and two females, ages 6 to 18 years. All showed increased mitotic activity (three to five mitoses per high-power microscopic field [250x]). Endothelial proliferation and necrosis were present in three and two cases each. DNA ploidy analysis showed the spontaneously occurring malignant-appearing tumors to be aneuploid, whereas both previously radiated tumors were tetraploid; 5% to 11% of cells were in S phase. The appearance of histologic malignancy in pilocytic astrocytoma is rare and less reliably correlated with prognosis than in patients with fibrillary astrocytomas. Essential features of such tumors include a high mitotic index and perhaps a high percentage of cells in S phase.

Adolescent↗

PubMed1993

Astrocytomas of the cerebellum. A comparative clinicopathologic study of pilocytic and diffuse astrocytomas.

BACKGROUND: The majority of patients with astrocytomas of the cerebellum have an excellent prognosis; however, a small percentage of patients continue to do poorly. To clarify the clinical, pathologic, and treatment characteristics that determine prognosis and therapeutic recommendations, a large group of patients with astrocytic tumors of the cerebellum was reviewed and analyzed. METHODS: A clinicopathologic analysis was performed of all patients undergoing initial operation for astrocytomas in the cerebellum between 1960 and 1984. Of the 132 patients, 105 patients had pilocytic astrocytomas and 27 had diffuse astrocytomas. RESULTS: Multivariate analysis revealed that the division of pilocytic and diffuse histologic type was the most significant prognostic factor influencing survival. The 5-year, 10-year, and 20-year survival rates were 85%, 81%, and 79%, respectively, for patients with pilocytic astrocytomas and 7%, 7%, and 7%, respectively, for patients with diffuse astrocytomas (P < 0.001). Pilocytic astrocytomas occurred in a younger age group and were more commonly cystic and completely resected. CONCLUSIONS: Astrocytomas of the cerebellum can be divided into two principal groups, the pilocytic and the diffuse astrocytomas, each of which has distinct clinical, pathologic, and prognostic characteristics.

Adolescent↗

PubMed1992

Radiosensitization of human tumor cells with levamisole.

Levamisole in combination with radiation and chemotherapeutic agents is being studied in clinical trials. The mechanism of interaction of levamisole with these modalities is unknown. In order to determine if there is direct interaction between radiation and levamisole, a series of colony-formation assays was performed with the use of two human tumor cell lines. Cells were exposed to 0-10 Gy of radiation, with or without the addition of 0-1000 microM levamisole. Exposure to levamisole alone had no effect on cell survival; however, the combination of continuous exposure to levamisole at concentrations approaching 1000 microM and radiation revealed a potentiation of radiation-induced cell killing.

Adenocarcinoma, Bronchiolo-Alveolar↗