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BACKGROUND: Epstein-Barr virus (EBV) is associated with many human neoplasms, including Burkitt's lymphoma (BL). Endemic BL in central Africa is more often EBV-associated than BL in the United States, where seroconversion for EBV occurs somewhat later than in Africa. Therefore, the EBV association rate in BL may correlate more with the socioeconomic status of the population studied, which influences the age of EBV seroconversion, than with such factors as malaria, which may relate to the overall higher incidence rate in endemic regions. METHODS: Forty-one patients with BL in Egypt, which differs both climatically and racially from central African countries (i.e., Kenya, Uganda) where BL is endemic, were analyzed. All biopsies were evaluated for EBV-encoded RNAs (EBER1) by RNA in situ hybridization, analyzed for p53 protein expression using the monoclonal antibody D07, and immunophenotyped using a panel of monoclonal antibodies that included L26 (CD20), Leu 22 (CD43), and A6 (CD45RO). Twelve cases were evaluable for EBV subtype by polymerase chain reaction with EBV-specific primers. RESULTS: The median age at diagnosis was 9 years (range, 2-22 years). The biopsy site was extranodal in 29 patients and nodal in 12 patients. All 41 cases were documented as B-cell neoplasms. A hybridization signal for EBER1 RNA was identified in greater than 95% of the neoplastic cells in 30 of 41 cases (73%), whereas no signal was observed in 11 cases (27%). Epstein-Barr virus subtype 1 was found in 10 patients, subtype 2 in two patients. Immunostaining for p53 was observed in greater than 5% of the neoplastic cells in 9 of 37 cases (24%). No significant correlation was observed between EBV positivity and sex, biopsy site, or p53 immunostaining. CONCLUSIONS: The prevalence of EBV in BL from Egypt is slightly lower than in BL in endemic regions, but significantly higher than in sporadic BL. Epstein-Barr virus positivity probably reflects the socioeconomic status of the patient population, and age at seroconversion. The prevalence of EBV subtype 1 suggests that immunodeficiency does not play a role in Egyptian Burkitt's lymphoma, in contrast to endemic Burkitt's lymphoma, in which holoendemic malaria is thought to contribute to immunodeficiency, a higher incidence rate, and the observed prevalence of subtype 2.

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The rate of cell production in thirty-five cases of carcinoma in Bilharzial bladder was evaluated from the labelling index after in vitro incubation with [3H]TdR. Squamous cell carcinoma was the most frequent histological type in this series and had a median LI of 8.0% which corresponds to a potential doubling time of 5.9 days. In squamous cell tumours the LI increased with the histological grade. Transitional cell tumours had a somewhat greater LI. In all histological types the LI was significantly greater in the deep infiltrating parts of the tumour than in the superficial parts. The discrepancy between the estimated potential doubling time and the growth rate normally attributed to such tumours suggests the existence of an extensive cell loss factor. Areas of focal or diffuse mucosal hyperplasia were associated with increased LI.

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A pathologic study of 135 cases of carcinoma of the bilharzial urinary bladder treated with radical anterior pelvic exenteration, including 60 cases examined by subserial sections of both ovaries, did not reveal a single incidence of ovarian metastases from bladder carcinoma. The same observation has been reported by some investigators examining the more aggressive forms of bladder carcinoma seen in Western countries. Based on these findings, we recommend that at least one ovary, the one away from the tumors, should be retained with an intact blood supply to avoid the distressing symptoms of menopausal syndrome. This is especially advisable in our patients where carcinoma of the bladder occurs at a younger age.

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The invasive potential of 15 brain tumors (seven meningiomas, and eight astrocytomas) as studied in cultures with Gelfoam used as a substrate. A three-stage system is introduced to classify in vitro invasiveness according to the depth of Gelfoam infiltration after 2 weeks' culture. This system proved to be simple and accurate. Meningiomas revealed greater activity in culture as compared to astrocytomas and infiltrated deeper into the Gelfoam. Dura mater explants were placed next to the culture of the tumors to study their interaction. Dura mater acted as a relatively strong barrier against tumor cell invasion in culture. In the majority of the explants, tumor cells revealed either contact arrest or spread underneath the dura and rarely spread over it. Tumor cells were seen infiltrating the dural explants in three cases, all of which were meningiomas.

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A study of the absorptive function of the small intestine in chidlhood malignant lymphomas was carried out at the Cancer Institute of Cairo University. The study comprised twenty-five children, with stage III or IV lymphoma. A complete lymphoma work-up was performed for each patient, comprising clinical, pathological, haematological, biochemical and roentgenological assessments. Evaluation of small intestinal function was done by means of mucosal biopsy, small bowel motor meal, xylose excretion test, and estimation of faecal fat excretion. These tests revealed evidence of malabsorption in 69% of the patients. The study provides a better understanding of childhood malignant lymphomas in Egypt, and shows that malabsorption may be more common in the disease than has been previously suspected.

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Exploratory laparotomy, splenectomy and liver biopsy were carried out as a pre-treatment staging procedure in 32 cases of pathologically proved malignant lymphoma with clinically palpable spleen. The spleen was found to be negative for lymphoma in 17 cases, of which liver pathology showed bilharzial hepatic fibrosis in eight cases, nutritional cirrhosis in two cases and non-caseating granuloma in three cases. The liver was clinically positive in 13 cases. After laparotomy, three cases showed bilharzial pathology only. Bilharziasis has accounted for about one half of the false positive hepato-splenic involvement. These findings exemplify the usefulness of laparotomy as a staging procedure in regions endemic for hepato-splenomegaly.

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