Lead poisoning--one approach to a problem that won't go away.

A reduction in sources of environmental lead exposure has resulted in substantial declines in mean blood lead concentrations of all age groups in the United States. However, some segments of the population continue to have unacceptable levels of lead exposure and elevated blood lead concentrations. In addition, virtually all residents of industrialized countries have bone lead stores that are several orders of magnitude greater than those of our preindustrial ancestors. Recent studies suggest that these skeletal lead stores adversely affect health and can contribute to reduced birth weights, aggressive behavior in children, and anemia, hypertension, and kidney disease in adults. Evidence is described that demonstrates that an increase in dietary calcium consumption can reduce lead absorption and toxicity from exogenous and endogenous lead exposure. A relatively inexpensive and effective way to reduce the substantial morbidity that will result from widespread lead exposure is by fortification of a variety of foods with low levels of calcium. This approach can complement other efforts to prevent lead exposure and reduce lead toxicity.     

晶体玻璃体视网膜联合手术治疗复杂性视网膜脱离

目的探讨玻璃体视网膜手术（ｖｉｔｒｅｒｅｔｉｎａｌｓｕｒｇｅｒｙ，ＶＲ术）联合晶体切除／超声粉碎的效果。方法对８１例（８１只眼）应用晶体玻璃体视网膜联合手术（ｌｅｎｔｉｃｕｌａｒ－ｖｉｔｒｅｏｒｅｔｉｎａｌｓｕｒｇｅｒｙ，ＬＶＲ术）治疗的复杂性视网膜脱离进行回顾性分析。结果解剖性成功者６４只眼（７９．０１％），功能性成功者４５只眼（５５．５６％）；手术成功率显著降低的原因是前部增殖性玻璃体视网膜病变（ｐｒｏｌｉｆｅｒａｔｉｖｅｖｉｔｒｅｏ－ｒｅｔｉｎｏｐａｔｈｙ，ＰＶＲ）（成功率４２．８６％，Ｐ＜０．０１）和术中／术后眼内出血（成功率５８．８２％，Ｐ＜０．０２５）。结论ＬＶＲ术是治疗复杂性视网膜脱离的主要方法；显著影响手术预后的因素是前部ＰＶＲ和术中／术后眼内出血。     

Diterpenoids from the Roots of Agastache rugosa

从土藿香根中得到两个二萜化合物，藿香酚（２）及异藿香酚（３）。经光谱解析（ＩＲ，ＵＶ，ＨＲＭＳ及ＮＭＲ谱），确定它们的结构分别为１１，１４ｄｉｈｙｄｒｏｘｙ１２ｍｅｔｈｏｘｙ１９（４→３）ａｂｅｏａｂｉｅｔａ４，（１８），８，１１，１３ｔｅｔｒａｅｎ７ｏｎｅ（２）和１１，１４ｄｉｈｙｄｒｏｘｙ１２ｍｅｔｈｏｘｙ１９（４→３）ａｂｅｏａｂｉｅｔａ３，８，１１，１３ｔｅｔｒａｅｎ７ｏｎｅ（３）藿香酚（２）为一新的化合物，而异藿香酚（３）系首次从天然界分离得到，二者为一对异构体。     

混合Poisson分布及其应用：疾病的统计分布（五）

本文讨论了混合Ｐｏｉｓｓｏｎ分布的性质、应用条件、参数的估计及混合Ｐｏｉｓｓｏｎ分布阶数的确定，指出混合Ｐｏｉｓｓｏｎ分布可用于混合样本的判别归类，并用Ｂａｙｅｓ的思想导出其判别归类方法。模拟试验结果表明：当混合Ｐｏｉｓｓｏｎ分布中各部分的比例相差不大，而各部分的均值相差较大时，抽样效果和拟合效果越好，所得到的估计值越接近理论值；反之效果越差。     

The effect of palytoxin on neuromuscular junctions in the anococcygeus muscle of the rat

Palytoxin, a highly toxic natural product isolated from zoanthids of the genus Palythoa, is accumulated by a wide range of fishes and marine invertebrates used as food in the Indo-Pacific. It is responsible for many incidents of human morbidity and mortality. The toxin is a potent smooth muscle spasmogen. The cause of the contraction of smooth muscle is unclear, but recent work strongly suggests that it is primarily initiated by the release of neurotransmitters from the motor innervation of the smooth muscle. We show here that palytoxin caused the swelling of the muscle cells and some internal organelles of the anococcygeus muscle of the rat, but no substantial structural damage to the tissue. Axons and Schwann cells were also swollen but the most dramatic feature was the depletion of synaptic vesicles from putative release sites in the axons. Some axons were physically damaged following exposure to the toxin, but this was relatively uncommon (<10% of all axons studied). In the majority of axons there was no damage to nerve terminal membranes, but there was damage to mitochondria. The depletion of vesicles involved all types – clear, dense-cored, large and small. Our observations and pharmacological data gathered elsewhere, provide a neuropathological basis for the spasmogenic activity of palytoxin.     

The role of ultrasound in the diagnosis of a large, rapidly growing, thyroid mass.

The value of ultrasound in the diagnosis of a large rapidly growing thyroid mass was assessed in a study of 42 patients with a large (> 3 cm) rapidly growing (< two months) solitary mass. Haemorrhage into a thyroid nodule was present in 31 patients and thyroid malignancy in 11. Ultrasound of haemorrhage into a thyroid nodule revealed a large cystic mass in all 31 patients containing internal debris (22), septations (three), or a combination of both (six). The malignant causes of a large rapidly growing mass were lymphoma (two), anaplastic carcinoma (four) and metastasis (five). Ultrasound of these thyroid malignancies revealed a mass with a smooth, well-defined margin and strikingly low homogeneous echogenicity in all cases. Patients with thyroid metastases had evidence of widespread metastatic disease elsewhere. Lymphoma was differentiated from anaplastic carcinoma on fine-needle aspiration cytology or surgical biopsy. Ultrasound was of value in differentiating between a benign haemorrhagic nodule and a malignant tumour. The various malignant tumours had similar appearances, however, and could not be distinguished on ultrasound.