[Prospective study on associations between levels of total cholesterol, triglyceride and risk of ischemic and hemorrhagic strokes].

OBJECTIVE: To explore associations between levels of total cholesterol (TC), triglyceride (TG) and incidence of ischemic and hemorrhagic strokes in populations. METHODS: Baseline investigations on stroke-related risk factors and physical examinations were performed in 10 093 (> 35 years) stroke-free urban community residents from 5 cities in China during May to July in 1987, follow-up investigations on stroke events were made during 1998 to 2000. The hazard ratios and 95% confidence intervals (CI) of ischemic and hemorrhagic strokes in middle, high tertiles of baseline TC or TG levels were compared with low baseline tertile residents using the Cox regression model. RESULTS: There were 491 first strokes during the 8-years cohort follow-up. Compared with the low tertile, risk of ischemic stroke in the middle and high tertiles of TC level was increased by 61% (HR: 1.61, 95%CI: 1.14-2.27) and 58% (HR: 1.58, 95%CI: 1.12-2.22) after adjustments for DBP, age, sex and other variables in the Cox proportional hazards model. Compared with the low tertile, risk of ischemic stroke in the high tertile of TG level was increased by 43% (HR: 1.43, 95%CI: 1.02-2.00). However, risk of hemorrhagic stroke in the middle and high tertiles of TC level decreased by 12% (HR: 0.88, 95%CI: 0.64-1.22) and 33% (HR: 0.67, 95%CI: 0.48-0.95) compared with the low tertile. CONCLUSIONS: Elevated serum TC and TG are independent risk factors for risk of ischemic stroke. However, low TC was related with increased risk of hemorrhagic stroke.

Effect of hyperbaric oxygen on cytochrome C, Bcl-2 and Bax expression after experimental traumatic brain injury in rats.

OBJECTIVE: To explore the effects of hyperbaric oxygen (HBO) treatment on the neuronal apoptosis at an earlier stage and the expressions of Cytochrome C (Cyt C), Bcl-2 (B-cell lymphoma-2 family) and Bax (Bcl-2 associated X protein) in rat brain tissues after traumatic brain injury (TBI). METHODS: Forty adult rats were divided into two groups, i.e., Group A (the rats with untreated TBI) and Group B (rats with HBO treatment after TBI). Sections of brain tissues of these two groups were then detected at 3, 6, 12, 24, 72 hours after TBI by immunohistochemistry and electronmicroscope, respectively. RESULTS: HBO treatment could up-regulate the expression of Bcl-2 within 72 hours, reduce the release of Cyt C from mitochondria, attenuate the formation of dimeric Bax and alleviate the mitochondrial edema within 24 hours after TBI. CONCLUSIONS: HBO treatment can alleviate neuronal apoptosis after TBI by reducing the release of Cyt C and the dimers of Bax and up-regulating the expression of Bcl-2.

Subtype hypertension and risk of stroke in middle-aged and older Chinese: a 10-year follow-up study.

BACKGROUND AND PURPOSE: Hypertension is the most important indicator of stroke. We aim to compare the long-term effects of the subtypes of hypertension on the risk of stroke in a Chinese cohort. METHODS: A total of 26,587 subjects > or =35 years of age and free of stroke were recruited in 5 cities in 1987. The subtypes of hypertension were defined as isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), systolic and diastolic hypertension (SDH), as well as managed hypertension (MHT), according to the criteria of systolic blood pressure > or =140 or diastolic blood pressure >90 mm Hg or under antihypertensive treatment. The relative risks of stroke with the subtypes of hypertension, compared with normotensives, were estimated using the Cox model after adjustments for age, sex, and other confounders. RESULTS: The prevalence of hypertension was: ISH 7.1%, SDH 18.4%, IDH 6.7%, and MHT 3.9%. During a total of 233 437 person years of follow-up, 1107 subjects developed stroke (614 ischemic and 451 hemorrhagic events and 42 unclassified). SDH patients were at the highest risk of stroke among all the hypertensives. The hazard ratio and 95% CI was 2.96 (2.49 to 3.52) for all stroke, 4.05 (3.10 to 5.30) for hemorrhagic, and 2.33 (1.84 to 2.95) for ischemic stroke. Although the incidence of stroke was higher in the older population, the effect of hypertension, especially SDH, on hemorrhagic stroke is stronger in the middle-aged population. CONCLUSIONS: ISH and IDH are similarly prevalent in the population; both are independent predictors of stroke. Patients with SDH are at the highest risk of stroke and should be treated more aggressively.

Effect of thyrotropin-releasing hormone on cerebral free radical reactions following acute brain injury in rabbits.

OBJECTIVE: To investigate the early effect of thyrotropin-releasing hormone (TRH) on cerebral free radical reactions after acute brain injury in rabbits. METHODS: 30 healthy white rabbits were randomly divided into three groups: Group A (n=10), Group B (n=12) and Group C (n=8). The rabbits in Group A and Group B were injured by direct hit. At 0.5-4 hours after injury, the rabbits in Group A were injected with TRH (8 mg/kg body weight) through a vein and the rabbits in Group B were injected with normal saline of equal volume. The rabbits in Group C served as the normal control. Then all the rabbits were killed and brain tissues were obtained. The content of lipoperoxide (LPO), the activity of superoxide dismutase (SOD) and the water content of the brain tissues were measured. RESULTS: The contents of LPO and water in brain tissues in Group A were lower and the activity of SOD was higher than those of Group B (P<0.05). After injury, intracranial pressure (ICP) rose rapidly and continuously with time passing by. When TRH was given to the animals in Group A, the rising speed of ICP slowed down significantly. CONCLUSIONS: TRH can decrease the cerebral free radical reactions and cerebral edema after acute brain injury in rats.