Posterior atlantooccipital subluxation in Down syndrome

Three Down syndrome patients with posterior atlantooccipital (AO) subluxation are described. All are asymptomatic. The subluxation becomes manifest during active extension of the neck and reduces in flexion. Methods of assessing posterior AO subluxation are discussed. The abnormality is attributed to ligamentous laxity in patients with Down syndrome.     

CD5-CD56+ T-cell receptor silent peripheral T-cell lymphomas are natural killer cell lymphomas [see comments]

Non-Hodgkin's lymphomas are divided into B- and T-cell neoplasms. The existence and the clinical relevance of lymphomas derived from the third lymphocyte lineage, ie, natural killer (NK) cells are still controversial. NK cells are lymphocytes that mediate cytotoxicity without prior sensitization. NK cells also have phenotypic and genotypic characteristics: they express the NK-related antigen CD56, T- cell markers such as CD2 and CD7, but do not express CD5 and T-cell receptor (TCR) proteins, and their TCR locus is not rearranged. Therefore, if NK cell lymphomas exist, they should express some T-cell markers, but not alpha beta or gamma delta TCR proteins. Such lymphomas are actually called TCR silent peripheral T cell lymphomas (PTCL). To detect and characterize NK cell lymphomas, we investigated the immunophenotype and immunogenotype of 35 patients with TCR silent PTCL. The first group included 16 patients with a lymphoma of CD5-CD56+ phenotype, which is identical to normal NK cells. These patients had either a nasal/nasopharyngeal lymphoma (11 cases) or a lymphoma with predominant non-nasal/non-nodal initial involvement (five cases). Eight of the nine cases for which immunogenotypic data were available lacked clonal rearrangement of the TCR gamma genes. Thus, these tumors are likely to be NK cell lymphomas. The second group of 15 cases had a CD5+ phenotype (14 were CD56-, and 1 was CD56+) and clonal rearrangement of TCR gamma genes, indicating that they were true PTCL with unproductive TCR rearrangement. The four remaining cases were CD5- CD56- lymphomas and disclosed either a clonal (two cases) or no clonal (two cases) rearrangements of the TCR gamma genes. Altogether these findings show that CD5-CD56+ so-called "TCR silent PTCL" bear the immunophenotype and immunogenotype of normal NK cells and display peculiar clinical features distinct from true PTCL.     

Oral sumatriptan: effect of a second dose, and incidence and treatment of headache recurrences

Oral sumatriptan in a dose of 100 mg aborts about 60% of migraine attacks within 2 h, but the headache may recur within 24 h. We investigated: (i) the incidence of headache recurrence after oral sumatriptan, (ii) whether a second tablet of sumatriptan at 2 h increases initial efficacy and/or (iii) prevents headache recurrence and (iv) whether a further tablet of sumatriptan treats headache recurrence. In a randomized, parallel-group clinical trial, 1246 patients treated one to three migraine attacks (with or without aura) with 100 mg oral sumatriptan. Two hours later they all took a double-blind randomized second tablet of sumatriptan (group I) or placebo (group II). Patients who initially improved, but then experienced headache recurrence took a further double-blind randomized tablet of sumatriptan or placebo. Proportions of patients who improved from moderate/severe headache to mild/none were similar in groups I and II at 2 h (55 vs 56%) and 4 h (80 vs 77%). Incidences of headache recurrence (moderate/severe-any grade of headache) and median times to headache recurrence were also similar: 22-32% at 16 h in group I and 25-33% at 16.5 h in group II. Sumatriptan was superior to placebo in treating headache recurrence: 74 vs 49% ( p = 0.017) in group I and 70 vs 30% ( p = 0.0001) in group II. Thus, one-fourth of patients experience headache recurrence at about 16 h after successful treatment of a migraine attack with 100 mg oral sumatriptan. A second tablet of sumatriptan at 2 h does not increase initial efficacy and neither prevents nor delays headache recurrence. A further tablet of sumatriptan is, however, highly effective in treating headache recurrence. All dose regimens were well tolerated.     

骨形态发生蛋白对去势大鼠股骨颈骨形态、骨密度和骨生物力学的影响

目的:观察在去势大鼠股骨颈植入牛骨形成蛋白后其骨形态、骨密度及骨强度的变化。方法:实验于2006-06/12在解放军兰州军区兰州总医院骨科研究所完成。①实验材料:普通级3个月龄wistar雌性大鼠60只。骨形态发生蛋白冻干粉剂(从幼龄牦牛新鲜长骨皮质中提取)。②实验分组:以同一只大鼠左右肢体为对照,右侧为实验侧,左侧为对照侧。③大鼠摘除卵巢制作绝经后骨质疏松模型经双能X射线骨密度仪检测筛选出造模成功的44只大鼠,实验侧距大转子0.5cm处股骨颈植入牛骨形成蛋白冻干粉剂,对照侧植入牛血清白蛋白。④实验评估:术后4周、8周时麻醉下处死大鼠取材,应用苏木精-伊红染色,组织切片后光镜下观察、CT扫描、双能X射线骨密度仪及万能生物力学机观察大鼠股骨颈骨形态学、骨皮质厚度、骨密度及骨强度的变化。结果:纳入造模成功后的44只大鼠均进入结果分析。①股骨颈骨组织形态学观察:4周时实验侧股骨颈局部骨小梁完整、连续性尚好;对照侧股骨颈局部骨小梁稀少、连续性中断,不完整。8周时实验侧股骨颈骨小梁致密,数量增多、完整,连接成网状结构、分布均匀;对照侧股骨颈骨小梁稀疏、变细、间距变大,呈髓腔扩大。②骨皮质厚度、骨密度及生物力学测定:4周时实验侧和对照侧股骨颈皮质厚度无明显差异,骨密度及最大载荷有明显差异(P<0.05);8周实验侧较对照侧骨皮质厚度明显增加、骨密度、最大载荷均增高[皮质厚度:(2.632±0.042),(1.728±0.034)mm,骨密度:(0.210±0.026),(0.182±0.029)g/mm2,最大载荷:(97.2±8.1),(85.6±7.9)N,P均<0.05]。结论:植入牛骨形成蛋白可以提高去势大鼠股骨颈局部骨皮质厚度、骨密度及生物力学强度,这将可能为绝经后骨质疏松性股骨颈骨折的防治提供一种新的途径。     

Partial chimerism after T-cell-depleted allogeneic bone marrow transplantation in leukemic HLA-matched patients: a cytogenetic documentation

We evaluated serially by cytogenetics the blood and marrow chimerism of 38 leukemic recipients of HLA-matched bone marrow transplants (BMT) who were prepared by high doses of alkylating agents and fractionated total- body irradiation (2.2 Gy X 5). Donor or host mitoses were identified by examination of sex chromosomes in 32 patients or by evaluation of the polymorphism of other chromosomes after specific banding in six patients. Twenty-four patients were recipients of untreated BMT, and 14 were recipients of T-cell-depleted BMT. In the 24 patients who received untreated BMT, all showed successful engraftment, and only three had a transient mixed chimera. In the 14 recipients of T-cell-depleted BMTs, four rejected their grafts, and seven had mixed chimeras; these mixed chimeras were more frequent in blood lymphocytes than in marrow cells and could be detected up to 26 months after BMT. This high frequency of partial chimerism after T-cell-depleted BMT by comparison with a control group suggests that the donor's T cells play an important role in the eradication of host residual hematopoiesis after allogeneic BMT.     

Leu 697-->Val mutation in mature von Willebrand factor is responsible for type IIB von Willebrand disease

Type IIB von Willebrand disease is characterized by the selective loss of high molecular weight von Willebrand factor (vWF) multimers from plasma and enhanced platelet agglutination of platelet-rich-plasma in the presence of low concentrations of ristocetin. We identified, in two related patients, a C-->G transversion resulting in the substitution of Valine for Leucine at position 697 of the mature subunit of vWF. We reproduced this mutation in vWF cDNA and expressed the recombinant protein in Cos-7 cells. The subunit composition and multimeric structure of mutated protein (rvWFLeu697Val) were similar to the wild- type recombinant (WTrvWF). Ristocetin-induced binding of rvWFLeu697Val to platelets was markedly increased in the presence of low doses of ristocetin and slightly increased with botrocetin as compared with that for WTrvWF, whereas collagen binding was not affected by the mutation. These data show that the Leu 697-->Val substitution is not a rare polymorphism but is responsible for the subtype IIB characteristic abnormalities identified in the two affected patients; however, it is not located in the area of vWF (amino acid 540 to amino acid 578) where most of the other type IIB mutations have already been reported.     

Isolation and characterization of gelatinase granules from human neutrophils

We recently confirmed the existence of gelatinase granules as a subpopulation of peroxidase-negative granules by double-labeling immunogold electron microscopy on intact cells and by subcellular fractionation. Further characterization of gelatinase granules has been hampered by poor separation of specific and gelatinase granules on both two-layer Percoll gradients and sucrose gradients. We have developed a three-layer Percoll density gradient that allows separation of the different granules and vesicles from human neutrophils; in particular, it allows separation of specific and gelatinase granules. This allows us to characterize these two granule populations with regard to their content of membrane proteins, which become incorporated into the plasma membrane during exocytosis. We found that gelatinase granules, defined as peroxidase-negative granules containing gelatinase but lacking lactoferrin, contain 50% of total cell gelatinase, with the remaining residing in specific granules. Furthermore, we found that 20% to 25% of both the adhesion protein Mac-1 and the NADPH-oxidase component cytochrome b558 is localized in gelatinase granules. Although no qualitative difference was observed between specific granules and gelatinase granules with respect to cytochrome b558 and Mac-1, stimulation of the neutrophil with FMLP resulted in a selective mobilization of the least dense peroxidase-negative granules, ie, gelatinase granules, which, in concert with secretory vesicles, furnish the plasma membrane with Mac-1 and cytochrome b558. This shows that gelatinase granules are functionally important relative to specific granules in mediating early inflammatory responses.