To test the hypothesis that bacterial contamination of menstrual blood could be a local biologic event in the development of endometriosis, menstrual blood was cultured and bacterial endotoxin was measured in menstrual blood and peritoneal fluid. Our results suggest that compared with control women, higher colony formation of Escherichia coli in menstrual blood and endotoxin levels in menstrual fluid and peritoneal fluid in women with endometriosis may promote Toll-like receptor 4-mediated growth of endometriosis.

Granulocytic sarcoma (chloroma) was present in 23 of 338 myelogenous leukemia patients autopsied in Hiroshima and Nagasaki during 1949‐1969. There was no evidence that granulocytic sarcoma was more frequent among those who received heavy atomic‐bomb irradiation, although the incidence of myelogenous leukemia was greatly increased in the heavily irradiated group compared with controls. Granulocytic sarcoma was found in 19 of 237 persons with acute myelogenous leukemia, in 3 of 77 with chronic myelogenous leukemia, and 1 of 24 with chronic myelogenous leukemia with blast crisis. It was distinguished from myelogenous leukemia by: significantly higher frequency in children and young adults; clinical manifestations of pain and tumor formation (often with exophthalmos) followed by paralysis and/or urinary incontinence; slightly shorter survival time; and greater intensity of leukemic infiltration in the pituitary. At autopsy, gross tumors occurred most frequently in bone, ovary, lymph nodes, kidney, dura, lung, arm, and breast. The pathogenesis of tumor formation in leukemia is discussed.

The human UBE3A gene shows brain-specific partial imprinting, and lack of a maternally inherited allele causes Angelman syndrome (AS), which is characterized by neurobehavioral anomalies. In several AS model mice, imprinted Ube3a expression is detected predominantly in the hippocampus, cerebellar Purkinje cells and the olfactory bulb. Therefore, imprinting of mouse Ube3a is thought to be region-specific with different levels of silencing of the paternal Ube3a allele in different brain regions. To determine cell types of imprinted Ube3a expression, we analyzed its imprinting status in embryonic brain cells by using primary cortical cell cultures. RT-PCR and immunofluorescence were performed to determine the allelic expression of the gene. The Ube3a gene encodes two RNA transcripts in the brain, sense and antisense. The sense transcript was expressed maternally in neurons but biallelically in glial cells in the embryonic brain, whereas the antisense transcript was expressed only in neurons and only from the paternal allele. Our data present evidence of brain cell type-specific imprinting, i.e. neuron-specific imprinting of Ube3a in primary brain cell cultures. Reciprocal imprinting of sense and antisense transcripts present only in neurons suggests that the neuron-specific imprinting mechanism is related to the lineage determination of neural stem cells.