Although the role of the epididymis, a male accessory sex organ, in sperm maturation has been established for nearly four decades, the maturation process itself has not been linked to a specific molecule of epididymal origin. Here we show that Bin1b, a rat epididymis-specific beta-defensin with antimicrobial activity, can bind to the sperm head in different regions of the epididymis with varied binding patterns. In addition, Bin1b-expressing cells, either of epididymal origin or from a Bin1b-transfected cell line, can induce progressive sperm motility in immotile immature sperm. This induction of motility is mediated by the Bin1b-induced uptake of Ca(2+), a mechanism that has a less prominent role in maintaining motility in mature sperm. In vivo antisense experiments show that suppressed expression of Bin1b results in reduced binding of Bin1b to caput sperm and in considerable attenuation of sperm motility and progressive movement. Thus, beta-defensin is important for the acquisition of sperm motility and the initiation of sperm maturation.

We analyzed the serum concentrations of lipids and lipoproteins and the prevalence of other risk factors in a case-control study of 304 consecutive Chinese patients with acute stroke (classified as cerebral infarction, lacunar infarction, or intracerebral hemorrhage) and 304 age-and sex-matched controls. For all strokes we identified the following risk factors: a history of ischemic heart disease, diabetes mellitus, or hypertension; the presence of atrial fibrillation or left ventricular hypertrophy; a glycosylated hemoglobin A, concentration of >9.1%; a fasting plasma glucose concentration 3 months after stroke of >6.0 mmol/1; a serum triglyceride concentration 3 months after stroke of >2.1 mmol/1; and a serum lipoprotein(a) concentration of >29.2 mg/dl. We found the following protective factors: a serum high density lipoproteincholesterol concentration of >1.59 mmol/1 and a serum apolipoprotein A-I concentration of a 106 mg/dl. The patterns of risk factors differed among the three stroke subtypes. When significant risk factors were entered into a multiple logistic regression model, we found a history of hypertension, a high serum lipoprotein(a) concentration, and a low apolipoprotein A-I concentration to be independent risk factors for all strokes. The attributable risk for hypertension was estimated to be 24% in patients aged >60 years. In this population, in which cerebrovascular diseases are the third commonest cause of mortality, identification of risk factors will allow further studies in risk factor modification for the prevention of stroke. (Stroke 1991;22:203-208) R isk factors for cerebrovascular diseases have been studied extensively in Caucasian and Japanese populations. 1 " 6 However, there are few studies examining apolipoproteins as risk factors. Also, there are few stroke studies among Chinese populations. No longitudinal or case-control studies of risk factors have been reported, few studies provide classification of stroke subtypes by computed tomography (CT), and the role of lipids and lipoproteins has not been investigated systematically. In this case-control study, we examined the serum concentrations of lipids, lipoproteins, and apolipoproteins and the prevalence of other risk factors in Chinese subjects with different stroke subtypes and estimated the attributable risks of some common risk factors for the Chinese population in Hong Kong.

The Shatin Stroke Registry is a prospective study of all patients admitted with acute stroke to a general hospital in Hong Kong where the population is predominantly Chinese. Each patient was examined by a neurologist and 95.5% of the patients had a brain CT. Of 777 patients included in the study, 44.0% had a cortical/subcortical infarct, 18.5% a supratentorial lacunar infarct, 24.2% a supratentorial intracerebral hemorrhage, 5.8% brainstem/cerebellar infarct, 2.9% a brainstem/cerebellar hemorrhage, and 4.5% an uncertain diagnosis. The overall 30-day case fatality rate was 25.4%. Comparison with five stroke registries from the West suggests that intracerebral hemorrhage occurs between two and three times more frequently in the Chinese than in Westerners. Whether there is any difference in the relative frequencies for lacunar infarction remains unclear.

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