Essential thrombocythemia

Essential thrombocythemia (ET) is an acquired myeloproliferative disorder (MPD) characterized by a sustained elevation of platelet number with a tendency for thrombosis and hemorrhage. The prevalence in the general population is approximately 30/100,000. The median age at diagnosis is 65 to 70 years, but the disease may occur at any age. The female to male ratio is about 2:1. The clinical picture is dominated by a predisposition to vascular occlusive events (involving the cerebrovascular, coronary and peripheral circulation) and hemorrhages. Some patients with ET are asymptomatic, others may experience vasomotor (headaches, visual disturbances, lightheadedness, atypical chest pain, distal paresthesias, erythromelalgia), thrombotic, or hemorrhagic disturbances. Arterial and venous thromboses, as well as platelet-mediated transient occlusions of the microcirculation and bleeding, represent the main risks for ET patients. Thromboses of large arteries represent a major cause of mortality associated with ET or can induce severe neurological, cardiac or peripheral artery manifestations. Acute leukemia or myelodysplasia represent only rare and frequently later-onset events. The molecular pathogenesis of ET, which leads to the overproduction of mature blood cells, is similar to that found in other clonal MPDs such as chronic myeloid leukemia, polycythemia vera and myelofibrosis with myeloid metaplasia of the spleen. Polycythemia vera, myelofibrosis with myeloid metaplasia of the spleen and ET are generally associated under the common denomination of Philadelphia (Ph)-negative MPDs. Despite the recent identification of the JAK2 V617F mutation in a subset of patients with Ph-negative MPDs, the detailed pathogenetic mechanism is still a matter of discussion. Therapeutic interventions in ET are limited to decisions concerning the introduction of anti-aggregation therapy and/or starting platelet cytoreduction. The therapeutic value of hydroxycarbamide and aspirin in high risk patients has been supported by controlled studies. Avoiding thromboreduction or opting for anagrelide to postpone the long-term side effects of hydrocarbamide in young or low risk patients represent alternative options. Life expectancy is almost normal and similar to that of a healthy population matched by age and sex.     

Essential Reading

In this issue of the Journal of Gene Medicine we are pleased to introduce a new section called ‘Essential Reading’. Members of the Journal's Editorial Board have been asked to suggest recent papers they have read which they consider noteworthy. Because space is limited, the section does not claim to be exhaustive, nor does the absence of an article imply that it is not important. Here is the Board's selection for this issue.     

Essential Reading

Articles cited in “Essential Reading” are a selection chosen by the Editorial Board of the Journal. Because space is limited, the section does not claim to be exhaustive, nor does the absence of an article imply that it is not important. Here is the Board's selection for this issue. Copyright © 2001 John Wiley & Sons, Ltd.     

Essential eukaryotic core

The AIDs-related fungal pathogen Pneumocystis carinii is unusual in having a remarkably compact genome of 7.7 megabase pairs (mbp) whose small size presents the opportunity to identify the essential eukaryotic core of genes. The essential eukaryotic core is defined to be a collection of essential genes shared by all eukaryotes. Sequencing the 3' ends of more than 5500 cDNAs from P. carinii allowed us to identify about 200 genes shared with its nearest known but distant relative, Schizosaccharomyces pombe and also Saccharomyces cerevisiae, and with homologs known to be essential in S. pombe or S. cerevisae. As the cDNA library contains about one half of the P. carinii genes, the size of the essential eukaryotic core (approximately 400) is slightly larger than the prokaryotic core (265-350) being identified by studies of the bacterial pathogen Mycoplasma genitalium. The collection of genes in the essential eukaryotic core may prove useful in identifying new broad spectrum antifungal drug targets.     

必需微量元素铬的研究

尽管30年前已经确定了铬是动物营养的必需微量元素,但对于这种元素的生理功能,特别是它对人体的生物学作用,只是近10年才得到了比较深刻的认识。这主要由于三个方面的原因:(1)食物和机体中的铬都以ng存在,要准确测量非常困难;(2)用实验动物观察铬的缺乏或过量,需配制无铬的合成饲料,对纯化饲料的技术要求很高;(3)难以确定机