Age-related changes in control of blood pressure and heart rate during sleep in the rat.

STUDY OBJECTIVES: The aim of this study was to determine age-related changes in the control of mean arterial pressure (MAP) and heart rate (HR) during sleep, and its relationship to the baroreflex in aging. DESIGN: MAP, HR, body temperature (TP), spontaneous activity (ACT), and sleeping/waking duration were monitored for 24 hours in groups of young (10-12 wk old) and old (23-24 mo old) rats. SETTING: The sleep laboratory at the University of Tokushima. PARTICIPANTS: Subjects were 8 young (10-12 wk old) and 7 old (23-24 mo old) Wistar rats. INTERVENTIONS: Reflex control of HR was evaluated by examining various pressure responses to an intravenous bolus injection of phenylephrine and sodium nitroprusside. MEASUREMENTS AND RESULTS: MAP and TP were recorded by a radiotelemetry system. HR was detected from the AP signal. ACT was counted by a photo-sensor system. In the case of old rats, the sensitivity of baroreflex control of HR was significantly depressed, and the spontaneous increase of MAP and HR during REM sleep and the MAP drop at the end of REM sleep were significantly enhanced. The old rats showed no large deterioration of the circadian profiles of MAP, HR, TP, and the amount of sleep. CONCLUSIONS: The baroreflex dysfunction is considered to appear in an early stage of the aging process, and to affect the control of MAP and HR during sleep.

Unusual skin reactions after mosquito bites and Epstein-Barr virus reactivation in a patient with mantle cell lymphoma.

We detected Epstein-Barr virus (EBV) reactivation in a patient with mantle cell lymphoma (MCL). The patient, a 53-year-old Japanese man, had been referred to our hospital because of generalized lymphadenopathy, hepatosplenomegaly and lymphocytosis and gave a history of intense skin reactions to mosquito bites. The biopsied lymph node contained a monotonous proliferation of medium-sized lymphocytes with scant cytoplasm and slightly irregular nuclei that were CD5+, CD20+ and CD23-. Antibody titers of IgG against EBV viral capsid antigen and early antigen were increased, and EBV was detected in the lymphoma cells. This case may suggest a relationship between EBV and MCL.

Soluble Fas in malignant pleural effusion and its expression in lung cancer cells.

Soluble Fas (sFas) has the ability to block Fas-mediated apoptosis, suggesting that sFas at tumor sites might inhibit tumor cell-killing by immune effector cells. We examined the sFas level in pleural effusion associated with lung cancer. The level of sFas in malignant pleural effusion was significantly higher than those in transudate and tuberculous pleural effusion. There was no significant difference in the sFas concentration among various histological types of lung cancer. The cytotoxicity mediated by anti-Fas agonistic antibody against Jurkat cells was inhibited by the addition of malignant pleural effusion, being inversely correlated with the sFas concentration. When Fas expression was examined using flow cytometry, eight of ten (80%) lung cancer cell lines expressed cell surface Fas. On the other hand, sFas protein and mRNA were detected in six of ten (60%) lung cancer cell lines, but there was no correlation between Fas and sFas expression. Furthermore, although the expressions of Fas and sFas were clearly detected in tumor cells derived from malignant effusion, the sFas expression was down-regulated in an in vitro culture. These results suggest that sFas in malignant pleural effusion is at least in part produced by lung cancer cells, and might play a role in local immunosuppression by tumor cells.