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Background: Because recognizable lesions are often absent, selection of biopsy sites for diagnosis of intravascular large B-cell lymphoma (IVL) is frequently problematic., Case: A 59-year-old woman was admitted with fever and general fatigue. Combined physical and roentgenographic examinations revealed neither lymphadenopathy, hepatosplenomegaly nor mass lesions in other organs. Serum lactate dehydrogenase level was 1412 IU/L. There were no genital symptoms, but uterine cytologic examination revealed large cells distributed in a noncohesive pattern. These cells had a large, irregularly shaped nucleus in which several nucleoli were discernible and showed positive immunoreactivity for leukocyte common antigen. Three months after admission, neurologic symptoms appeared, and magnetic resonance imaging revealed multiple nodular lesions in the brain. Biopsy specimens from the brain lesion showed the proliferation of large lymphoid cells filling the lumina of small vessels and Virchow-Robin's space. Immunohistochemistry revealed that the tumor cells were positive for CD20 and CD79a but negative for CD3, indicative of IVL., Conclusion: Uterine cytologic and/or histologic examinations could be the choice for diagnosis of IVL, even when genital symptoms are absent.

A 45-year-old woman with breast cancer was admitted to our hospital because of several episodes of disturbed consciousness and generalized convulsions. While these symptoms resolved quickly, dysphagia and bilateral blepharoptosis persisted. Neurological findings were improved by steroid therapy. MRI on the first hospital day showed T2/FLAIR high intensity lesions in both occipital lobes, but these lesions diminished on the 8th day, indicating reversible posterior leukoencephalopathy syndrome. A new lesion appeared in the left temporal lobe on the 8th day. A diagnosis of Hashimoto's encephalopathy (HE) was made due to the following features: 1) encephalitis not due to herpes simplex virus, 2) high titers of antithyroid antibodies in serum, 3) marked effectiveness of steroid therapy, and 4) antibodies against the amino terminal of alpha-enolase, a specific antigen for HE.

Nitric oxide (NO) is considered to be associated with the pathogenesis of cerebral ischemic injury. In the present study, NO production was continuously monitored employing in vivo microdialysis. A microdialysis probe was inserted into the stratum. Levels of the major NO metabolite, NO-2, in the dialysate were determined using the Griess reaction. Rats were subjected to global cerebral ischemia produced by occlusion of both common carotid arteries together with induced hypotension. Cerebral ischemia induced a decrease in NO production, which was interrupted by a transient increase in NO synthesis. This increment was abolished in the presence of a NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), suggesting that NO synthase activity is transiently activated during ischemia. Following reperfusion, NO synthesis was enhanced. To our knowledge, this is the first report concerning the continuous temporal profile of NO production during global cerebral ischemia and reperfusion.

A novel spectrophotometric nitrite (NO2-)/nitrate (NO3-) assay system for a small quantity (5 microliter) of dialysate sample obtained by in vivo brain microdialysis was developed based on the diazotization reaction. The system has the advantage of in vivo consecutive measurement, high precision, good reproducibility, technical simplicity, relatively short resolution time (2.5-20 min), and wide availability. The NO3- level in the rat striatum was found to be 3 times higher than the NO2- level. A nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester, reduced striatal NO2-/citrulline formation in a dose-related manner and increased arginine, indicating that the tissue NO2- level detected by this assay system adequately reflects the striatal NO synthase activity.