Platelet function in autoimmune (idiopathic) thrombocytopenic purpura

Platelets play an essential role in the formation of haemostatic plugs. The quantitative defect of platelets in autoimmune (idiopathic) thrombocytopenic purpura (ITP) can result in bleeding complications, but most ITP patients have platelets with normal or enhanced function. Platelets in ITP are large, young, so-called "stress" platelets with increased platelet-associated autoimmune antibody (immunoglobulin G). Young stress platelets are more functional platelets, and their presence may account for bleeding times in ITP patients that are shorter than would be predicted on the basis of the patients' (low) platelet counts. Some ITP patients have significant mucocutaneous bleeding with platelet counts >50 × 10⁹ l⁻¹; this may be due to qualitative platelet dysfunction (e.g. brought about by inhibitory antiplatelet autoantibodies).     

Correlates of prone infant sleeping position by period of birth

Intervention to avoid the prone sleeping position during infancy has occurred in various countries after evidence that it increases the risk of sudden infant death syndrome (SIDS). This study examined cohort data to determine if correlates of the prone position differed by period of birth, before intervention (1 May 1988 to 30 April 1991) compared with after intervention (1 May 1991 to 30 April 1992). The usual prone sleeping position was more closely associated with the following factors after intervention: teenage motherhood, low maternal education, paternal unemployment, unmarried motherhood, non-specialist antenatal care, not reading books to prepare for a baby, poor smoking hygiene, and bottle feeding. For example, the association of usual prone position with being unmarried shown by the odds ratio (95% confidence interval) was 0.54 (0.47 to 0.63) in the period before intervention and 1.92 (1.18 to 3.15) in the period after intervention. The alteration in correlates of the prone position reported here provide an example to support the theoretical concept that well known 'modifiable' risk factors for disease tend to be associated with each other in both populations and individuals. This phenomenon was not evident in the population before intervention, that is, before the prone sleeping position became a well known SIDS risk factor.     

Cerebral blood flow velocity in term newborns following intrapartum fetal asphyxia

Twenty-six term newborns with intrapartum fetal asphyxia, determined biochemically (umbilical artery base deficit < 12mmol/1), were compared with 59 normal newborns to determine the effect of intrapartum fetal asphyxia on newborn blood pressure and cerebral blood flow velocity following delivery. Cerebral blood flow velocity observations with concurrent measures of blood pressure and heart rate were obtained during the 24 h after delivery and after 24 h. After delivery, diastolic blood pressure in the newborns of the asphyxia group was significantly greater than that of the newborns of the normal group and this difference persisted after 24 h. Cerebral blood flow velocity in the newborns of the asphyxia group was of the same order as that of the newborns of the normal group during the 24 h after delivery. However, there was a significant increase in both peak systolic and end-diastolic blood flow velocity after 24 h. The duration of metabolic acidosis may be a factor in the occurrence of this delayed cerebral blood flow velocity response. Observations of cerebral blood flow velocity should be continued for more than 24 h following delivery to determine the effect of intrapartum fetal asphyxia.     

低场强MRI对于颅内转移瘤诊断价值的分析

目的:评价探讨低场强磁共振检查在脑转移瘤中的诊断价值。方法:用0.3 T开放型磁共振成像系统对30例脑转移瘤患者的磁共振平扫、水抑制(FIR)和增强扫描-采用静脉快速推注顺磁性造影剂Gd-DTPA(0.2 ml/kg)结果进行分析。结果:30例中单发病灶8例,多发22例,平扫发现48个病灶,FIR发现72例,增强扫描发现96个病灶,65个病灶直径大于3 cm;发现最小病灶直径3 mm;伴发空洞54例。增强扫描发现平均每个病人有3.2个病灶。结论:MRI是脑转移瘤不可缺少的检查方法,低场强磁共振检查既可准确发现微小和特殊部位的转移灶,又可得到病灶的边缘形态和内部情况以便于治疗方案的确定。