A new variant of type II von Willebrand disease with aberrant multimeric structure of plasma but not platelet von Willebrand factor (type IIF)

A patient with a lifelong bleeding disorder was diagnosed as having Type II von Willebrand disease. The larger multimers of von Willebrand factor were absent from her plasma but present in platelets. A high- resolution electrophoretic technique was used to study the complex structure of individual von Willebrand factor multimers. In normal plasma, each multimer could be resolved into five bands: a more intense central one and four less intense, two moving faster and two slower than the central band. In normal platelets, each multimer could also be resolved into five bands. The central one had a mobility similar to that in plasma, whereas the four satellite bands had a mobility that differed from that of the corresponding plasma bands. In the patient, platelet von Willebrand factor antigen content and ristocetin cofactor activity were normal, and von Willebrand factor showed the same structure of individual multimers as seen in normal platelets. On the other hand, plasma von Willebrand factor antigen and ristocetin cofactor activity were decreased, and the structure of individual von Willebrand factor multimers was different from that of normal plasma and similar to that seen in normal and patient's platelets. After infusion of 1-deamino-8-D-arginine vasopressin, the largest von Willebrand factor multimers, as well as new satellite bands with a mobility similar to those in normal plasma, appeared in the patient plasma, and the levels of von Willebrand factor antigen and ristocetin cofactor activity became normal. Yet no relevant change in the prolonged bleeding time was observed. This new variant of von Willebrand disease, therefore, is characterized by the presence of a dysfunctional von Willebrand factor molecule that exhibits unique structural abnormalities in plasma but appears to be normal in platelets. The designation of Type IIF is proposed for this type of von Willebrand disease in accordance with the terminology that has been previously used.     

自体髂骨植骨带锁钢板内固定材料置入并一期前后路减压治疗多节段脊髓型颈椎病12例:临床资料回顾分析

目的:严重的多节段脊髓型颈椎病单纯前路或后路手术都有其局限性。观察一期前后路联合手术并自体髂骨植骨及带锁钢板内固定材料置入在治疗多节段脊髓型颈椎病中的应用价值。方法:选择2004-11/2006-12本院12例多节段脊髓型颈椎病患者,均采用一期前后路减压、自体髂骨植骨融合、带锁钢板内固定联合手术。其中男9例,女性3例,年龄49～75岁;3节段受累9例,4节段受累3例(突出节段分布:C3～66例,C4～73例,C3～73例)。全部病例进行临床随访,患者均对本试验知情同意。采用mJOA评分标准对患者神经功能改善情况进行评定;术前颈椎侧位片测量,以D值(C4椎体后下缘到齿突后缘与C7椎体后下缘连线的垂直距离)评价颈椎(C2～7)弧度;根据颈椎伸屈动态侧位片C2和C7椎体后缘切线相交所成的夹角之和评价颈椎(C2～7)活动范围。主要以电话随访和问卷填写的方式,分别从神经功能改善情况、颈椎弧度、活动范围及术后并发症等进行随访观察。结果:①12例患者全部得到随访,术后随访时间6～28个月,平均(16±6)个月。②所有植骨均获得骨性愈合;疗效结果中优4例(33.3%);良6例(50%);无效2例(16.7%);颈椎D值术前(3.9±1.4)mm,术后即刻(8.5±1.7)mm,随访时(8.1±2.5)mm。术前与术后差异有显著性(P<0.01),术后与随访时差异无显著性(P=0.251);颈椎活动范围术前(36.3±4.0)°,随访时(10.6±2.7)°,与术前相比差异具有显著性(P<0.01)。③术后C5神经根麻痹1例,为感觉及运动混合型,8个月随访时,感觉功能恢复,肩关节外展肌力从术后Ⅱ级恢复至Ⅳ级;1例术后6个月出现"S"畸形而再次压迫脊髓,神经功能改善停滞,目前处于随访中。结论:一期前后路手术并自体髂骨植骨及带锁钢板内固定材料置入减压充分、彻底,而且前路手术能重建颈椎稳定性,恢复颈椎生理前凸和椎间高度,并且后路减压术又能预防相邻颈椎退变引起的脊髓继发的压迫。     

DFNB74, a novel autosomal recessive nonsyndromic hearing impairment locus on chromosome 12q14.2-q15

Autosomal recessive nonsyndromic hearing impairment (ARNSHI) segregating in three unrelated, large consanguineous Pakistani families (PKDF528, PKDF859 and PKDF326) is linked to markers on chromosome 12q14.2-q15. This novel locus is designated DFNB74 . Maximum two-point limit of detection (LOD) scores of 5.6, 5.7 and 2.6 were estimated for markers D 12 S 313, D 12 S 83 and D 12 S 75 at θ = 0 for recessive deafness segregating in these three families. Haplotype analyses identified a critical linkage interval of 5.35 cM (5.36 Mb) defined by D 12 S 329 at 74.58 cM and D 12 S 313 at 79.93 cM. DFNB74 is the second ARNSHI locus mapped to chromosome 12, but the physical intervals do not overlap with one another. A locus contributing to the early onset, rapidly progressing hearing loss of A/J mice ( ahl4 , age-related hearing loss 4) was reported to map to chromosome 10 in a region of conserved synteny to DFNB74 , suggesting that ahl4 and DFNB74 may be due to mutations of the same gene in these two species.     

Immunolocalization of Le(y) oligosaccharide in endometrium during menstrual cycle and effect of early luteal phase mifepristone administration on its expression in implantation stage endometrium of the rhesus monkey

Changes in carbohydrate expression on endometrial and blastocyst cell surfaces may play a critical role in the process of implantation. Le(y) is an oligosaccharide antigen which has been shown to be involved in blastocyst attachment in the mouse. In the present study, immunohistochemical distribution of Le(y) in endometrium during proliferative and secretory phases of normal menstrual cycles in the rhesus monkey was examined. Endometrial samples were collected on cycle days 7 (n=4), 13 (n= 4), 16 (n=4), 20 (n=4) and 25 (n=3). There was a gradual increase of Le(y) in luminal surface from proliferative to periovulatory (P < 0.001), and from periovulatory to postovulatory (P < 0.05), phases. Le(y) then remained constant in the midsecretory phase and decreased (P < 0.01) during the premenstrual phase. Le(y) score in glands did not change between the phases, except in midsecretory phase when it was higher than that in other phases (P < 0.05). The stromal compartment showed no statistically significant changes. The profiles of endometrial Le(y) on day 6 after ovulation in mated fecund cycles with or without early luteal phase mifepristone treatment were also examined. Females were allowed to cohabit with males during days 8-16 of their ovulatory cycles and were injected s.c. with vehicle (n=7) only, or with a single dose of mifepristone (2 mg/kg body weight; n=8) on day 2 after ovulation. Significant decreases in the area and optical absorption of immunoprecipitate were observed in the epithelial compartment (P < 0.01) following mifepristone treatment. There was no change in the stromal compartment either in area or in optical absorption of immunoprecipitate for Le(y) with or without mifepristone treatment. The expression of Le(y) in the endometrial epithelial compartment appears to be influenced by progesterone and may be associated with endometrial receptivity prior to implantation in the rhesus monkey.      

葡萄糖酸镁对离体大鼠心肌缺血再灌注细胞凋亡的抑制效应

目的:观察葡萄糖酸镁对离体大鼠心肌缺血再灌注损伤心肌细胞凋亡的影响。方法:实验于2005-10/2006-01在辽宁医学院药理实验室完成。选用雄性SD大鼠48只,体质量250～300g,按随机排列表法将大鼠分为对照组、缺血再灌注组、葡萄糖酸镁组,每组16只,建立Langendorff离体大鼠心肌缺血再灌注损伤模型。(1)每组各取8只:①对照组:改良的K-H缓冲液持续灌流110min。K-H缓冲液成分(mmol/L)如下:NaCl118.1,NaHCO325.0,KH2PO41.2,MgSO40.6,CaCl22.0,KCl4.7,Glucose11.0。②缺血再灌注组:改良的K-H缓冲液持续灌注至各项指标稳定后,约20min,停灌30min,再灌60min。③葡萄糖酸镁组:灌注方法同缺血再灌注组,但将K-H缓冲液内加葡萄糖酸镁2.4mmol/L。取左室心肌标本测总超氧化物歧化酶活性,丙二醛、Ca2 含量。(2)每组其余8只:①对照组K-H缓冲液持续灌流170min。②缺血再灌注组和葡萄糖酸镁组持续灌注至各项指标稳定后停灌30min,再灌注120min。观察对细胞凋亡的影响。(3)组间计量资料差异比较采用单因素方差分析。结果:SD大鼠共48只均进入结果分析。①缺血再灌注组大鼠心肌组织中丙二醛、Ca2 含量较对照组明显升高(P<0.01),总超氧化物歧化酶活性较对照组明显降低(P<0.01)。②葡萄糖酸镁组与缺血再灌注组比较,总超氧化物歧化酶活性明显升高(P<0.01),丙二醛、Ca2 含量明显降低(P<0.01)。③缺血再灌注组细胞凋亡指数显著高于对照组(P<0.01)。④葡萄糖酸镁组细胞凋亡指数与缺血再灌注组比较显著降低(P<0.01)。结论:葡萄糖酸镁有抑制心肌缺血再灌注损伤中心肌细胞凋亡的作用。其机制可能与葡萄糖酸镁减轻钙超载、清除氧自由基、减少脂质过氧化有关。     

The heterogeneity of type IIA von Willebrand's disease: studies with protease inhibitors

The absence of large von Willebrand factor (vWF) multimers from plasma is a characteristic of Type IIA von Willebrand's disease (vWD) and is thought to contribute to the clinical expression of this disorder. Recently, three IIA patients have been reported in whom intermediate and large multimers could be restored if blood were collected in 5 mm EDTA, 6 mmol/L N-ethylmaleimide, and 1 mmol/L leupeptin. This suggested that absence of large multimers resulted from in vitro proteolysis. We have now collected blood from ten Type IIA vWD patients in these inhibitors but were not able to detect large multimers in the plasma of any of them. In addition, intermediate-sized multimers were reduced or completely absent in all. The inclusion of inhibitors in the citrate anticoagulant, as compared to citrate alone, was found to increase the relative proportion of intermediate multimers in some patients but had no effect in others, and in none did it restore large multimers to plasma. The results with platelet vWF were more varied. Four patients showed an absence or decrease of large multimers, whereas in seven patients large multimers were present. When compared with citrate anticoagulant alone, the inclusion of inhibitors in the anticoagulant had little or no effect on the platelet multimeric pattern. 1-Deamino-8- D-Arginine Vasopressin (DDAVP) was administered to six patients from five families. Two patients from one family showed complete correction and a third patient showed almost complete correction of her bleeding time. Two patients showed minimal correction and one showed no detectable correction. An increase in multimer size after DDAVP tended to be associated with correction of the bleeding time. However, in no case did the largest multimers appear in plasma even in patients with complete bleeding time correction. The presence or absence of inhibitors in the anticoagulant had little or no effect on the multimeric pattern after DDAVP. These results indicate that Type IIA vWD is a heterogeneous disorder in which absence of largest and intermediate multimers is an in vivo phenomenon.     

Increased surface expression of the membrane glycoprotein IIb/IIIa complex induced by platelet activation. Relationship to the binding of fibrinogen and platelet aggregation

Platelet activation altered the binding of three monoclonal antibodies (monovalent Fab' fragment) directed against the glycoprotein (GP) IIb/IIIa complex. An increased binding of two- to threefold occurred after stimulation with thrombin or phorbol myristate acetate (PMA), with slight but significant increase in the dissociation constants (Kd) of two antibodies (LJ-CP8 and LJ-P9). In contrast, no statistically significant changes were observed with ADP-stimulated platelets. The increased binding of LJ-CP3, but not of the other two antibodies, to activated platelets decreased by 30% to 40% in the presence of EDTA at 22 to 25 degrees C. Platelets stimulated by thrombin or PMA bound more fibrinogen than did those stimulated by ADP, and significant differences in the extent but not in the affinity of fibrinogen binding were observed with various platelet agonists. When the pool of GP IIb/IIIa molecules exposed on the surface of unstimulated platelets was reacted with the monoclonal antibody LJ-CP3 to block ADP-induced fibrinogen binding and platelet aggregation, stimulation with thrombin or PMA still induced substantial binding of antibody and fibrinogen, and aggregation ensued. Therefore, platelets exposed to "strong" agonists exhibit an increased number of surface-oriented epitopes associated with GP IIb/IIIa. The GP IIb/IIIa molecules bearing these newly exposed epitopes are functional in that they can bind fibrinogen and mediate platelet aggregation.