Erythroid failure in Diamond-Blackfan anemia is characterized by apoptosis

Programmed cell death, also known as apoptosis, is frequently initiated when cells are deprived of specific trophic factors. To investigate if accelerated apoptosis contributes to the pathogenesis of Diamond- Blackfan anemia (DBA), a rare pure red blood cell aplasia of childhood, we studied the effect of erythropoietin (epo) deprivation on erythroid progenitors and precursors from the bone marrow of DBA patients as compared with hematologically normal controls. Apoptosis in response to epo deprivation was evaluated by enumeration of colony-forming unit- erythroid (CFU-E)- and burst-forming unit-erythroid (BFU-E)-derived colonies in plasma clot semisolid culture and by the identification of typical DNA oligosomes by gel electrophoresis from marrow mononuclear cells in liquid culture. In all DBA patients there was a marked decrease in CFU-E- and BFU-E-derived colony formation compared with normal controls at comparable time points of epo deprivation, with a complete loss of CFU-E-derived colonies in semisolid culture by 9 hours of epo deprivation versus 48 hours in controls. The BFU-E-derived colony response to epo deprivation displayed a similar pattern of decrement. Apoptotic changes assessed by the presence of characteristic DNA fragmentation began in the absence of epo deprivation and were readily detected within 3 hours of epo deprivation in DBA cultures versus 9 hours in controls. We conclude that DBA is characterized by accelerated apoptosis as measured by the loss of erythroid progenitor clonogenicity and increased progenitor and precursor DNA fragmentation leading to the formation of characteristic oligosomes, consistent with an intrinsic erythroid-progenitor defect in which increased sensitivity to epo deprivation results in erythroid failure.     

胰岛素样生长因子与胎儿宫内发育迟缓

０　引言　胎儿宫内发育迟缓（ＩＵＧＲ）是指出生体质量小于其孕龄平均体质量的第１０百分位者,或者小于其平均体质量的两个标准差者．发病率约为３％～４％．ＩＵＧＲ是围产儿死亡的重要原因之一,新生儿期及远期发病率明显增高．在儿童期比正常儿体格和智力发育均落后．还有研究提示ＩＵＧＲ和成年期发生糖尿病及心血管病有因果联系［１］．鉴于以上原因,ＩＵＧＲ的病因探讨越来越受到人们的重视,尤其是对ＩＵＧＲ内分泌方面的研究也越来越深入．本文着重综述近年来胰岛素样生长因子（ｉｎｓｕｌｉｎｌｉｋｅｇｒｏｗｔｈｆａｃｔ…     

神经节苷脂GM1对乙醇引起的神经膜磷脂脂肪酸参入变化的影响

研究神经节苷脂ＧＭ１对乙醇引起的神经膜磷脂的脂肪酸参入变化的影响。使用同位素标记的脂肪酸测定其对神经膜磷脂不同组分的参入率，比较ＧＭ１和乙醇对参入率的影响。慢性乙醇暴露发迹了不饱和脂肪酸「油酸，亚油酸，花生四烯酸和二十二碳六烯酸」参入到旨酰肌醇，磷脂酰丝氨酸和磷脂酰胆碱。     

Exudative macular degeneration and intravitreal triamcinolone: 18 month follow up

Purpose: To evaluate the safety and efficacy of intravitreal triamcinolone after 18 months of follow up in patients with age-related macular degeneration and subfoveal or juxtafoveal choroidal neovascularization considered unsuitable for laser photocoagulation. Methods: Thirty eyes of 28 patients, referred from general eye clinics as well as the private clinic of one of the authors to a hospital-based retinal out-patient clinic, were treated with an intravitreal injection of triamcinolone (4mg). The primary outcome measure was the proportion of eyes with loss of six or more lines on a Bailey-Lovie Chart. The incidence of adverse events associated with treatment was also observed. Results: Of the 20 eyes with initial visual acuity (VA) of 6/60 or better, the vision was maintained (± 1 Bailey-Lovie lines) in 11 eyes (55%), while six eyes (30%) suffered severe visual loss (six or more lines). The VA improved by five to six lines in three of 10 eyes with initial vision of 3/60 or worse. Three of four eyes receiving a second injection suffered either progressive cataract or elevated intra-ocular pressure (IOP) requiring cataract surgery and/or filtering surgery. One of 26 eyes (3%) receiving a single injection showed progression of cataract and elevation of IOP within 6 weeks of treatment and required anti-glaucoma medication for 6 weeks. Progression of nuclear sclerosis 8–12 months after treatment was observed in six of 26 eyes (23%) receiving a single injection. Conclusions: The results of the present study suggest that a single intravitreal injection of 4 mg triamcinolone is reasonably well tolerated by the human eye. The rate of development of severe visual loss was less than reported for historical controls. Because the results are preliminary and uncontrolled, the treatment should not be used routinely until its benefit to patients is established by a prospective, randomized controlled study.