Breathing During Sleep in Patients with Myotonic Dystrophy and Non-myotonic Respiratory Muscle Weakness

Sleep apnoea and hypopnoea have been reported in myotonic dystrophy,but it is unclear whether this is simply attributable to therespiratory muscle weakness which is common in this condition.We therefore investigated whether breathing and oxygenationduring sleep were more abnormal in patients with myotonic dystrophythan in patients with non-myotonic muscle weakness. Seven subjectswere studied in each of three groups: normal controls, myotonicdystrophy and non-myotonic weakness. Patients in the lattergroup were chosen to represent a similar range of severity ofrespiratory muscle weakness to those with myotonic dystrophy.Detailed polysoranography was performed; the severity of breathingdisorders during sleep was quantified in terms of the frequenciesof apnoea and hypopnoea and the degree of arterial desaturation.The myotonic patients showed more frequent apnoea and hypopnoeaand more severe desaturation than the other two groups; theresults in the non-myotonic patients were generally intermediate.The results suggest that abnormal breathing during sleep iscommon in myotonic dystrophy and is not due solely to the directeffects of respiratory muscle weakness. Somnolence, which isa well recognized symptom of myotonic dystrophy, was not clearlyattributable to the sleep apnoea/hypopnoea syndrome nor to abnormalsleep architecture in the myotonic patients.     

二氢吡啶类钙拮抗剂对钙调素依赖性环核苷酸磷酸二酯酶的抑制机理

用单克隆抗体纯化的60kd为亚基的牛脑钙调素依赖性环核苷酸磷酸二酯酶的动力学研究表明,二氢吡啶类钙拮抗剂Nicardipine和Felodipine是该酶的“部分”竞争性抑制剂。因为近饱和浓度的药物抑制该酶活性仅能达到某限定值,且Dixon作图法不呈直线关系。该酶被一定浓度Felo-dipine抑制时,增加Nicardipine浓度可逆转酶的抑制而达到Nicardipine的最大抑制水平,Nicardipine不影响典型的竞争性抑制剂甲基异丁基黄嘌呤对该酶的抑制作用,说明该酶活性中心以外存在和二氢吡啶结合的部位。     

Autosomal dominant cerulean cataract is associated with a chain termination mutation in the human beta-crystallin gene CRYBB2

Congenital cataracts are a common major abnormality of the eye that frequently cause blindness in infants. At least a third of all cases are familial; autosomal dominant congenital cataract (ADCC) appears to be the most common familial form in the Western world. Cerulean cataracts have peripheral bluish and white opacifications in concentric layers with occasional central lesions arranged radially. Although the opacities may be observed during fetal development and childhood, usually visual acuity is only mildly reduced until adulthood, when lens extraction is generally necessary. We have been studying a family (ADCC- 1) with cerulean blue ADCC, in which the affected daughter of a first cousin mating was presumed to be homozygous for the cataract gene. Recently, we mapped an ADCC gene in this family to a region of chromosome 22 containing three beta-crystallin genes. Here we report that a chain-termination mutation in CRYBB2 is associated with ADCC in this family.      

研究环境香烟烟雾暴露方法上必需考虑的问题

本文对在美国所进行的不吸烟者环境香烟烟雾（ＥＴＳ）暴露水平的大样本研究作了综述。内容包括取样地点的特定要求，收集样本的时间问题，评估ＥＴＳ暴露的合理标记物，以及用独立的方法去核实被检者自述ＥＴＳ暴露情况。以下是一些最重要的结论：（ａ）ＥＴＳ暴露的实际浓度比以前各地测量结果或短期暴露结果的预期浓度为低。（ｂ）家庭中的接触比工作场所更重要（浓度×暴露时间），约高２～１０倍。（ｃ）被检者报告吸烟情况的错误率比美国环保署（ＥＰＡ）先前所估计的高。（ｄ）用唾液古丁（Ｃｏｔｉｎｉｎｅ）含量来评估ＥＴＳ中尼古丁暴露的定量指标并不合适，因有个体差异