Exclusion mapping of 12 X-linked disease loci and 10 DNA probes from the long arm of the X-chromosome

Specific chromosome rearrangements associated with disease entities are invaluable resources for physical mapping. A deletion on the X chromosome of a male leads to the nullisomy for X-linked genes, resulting in the onset of genetic diseases and/or the absence of the DNA probe detectable sequences. This permits the localization of these loci within the deleted area. On the other hand, the region for some other X-linked loci can be excluded from the deleted area according to the absence of the characteristic symptoms of the disease and/or the presence of the hybridization signals. An interstitial deletion on the long arm of the X chromosome of a male has been characterized by high resolution banding. The karyotype of the proband is 46,Y,del(X)(pter----q21.1::q21.33----qter). The regions for 12 X-linked disease loci as well as 10 DNA probes are excluded from the deleted area, and localized either proximally or distally to the deletion. The results also reveal a controversy in the present linkage data concerning the assignment of these loci.     

Human mini-chromosomes in mouse embryonal stem cells

We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb in size into mouse embryonal stem cells. Although these human mini- chromosomes are stable in hamster and chicken cells, they re-arrange or segregate aberrantly in the embryonal stem cells and are rapidly lost in the absence of selection. However, one of the mini-chromosomes re- arranged, acquired mouse centromeric sequences and was then stably maintained for at least 60 population doublings in culture. This mini- chromosome, which is 4 Mb in size, is a candidate for a mouse germ line chromosome vector.      

乙酰胆碱酯酶阳性神经元在鼠脑的分布和形态特征

本文用乙酰胆碱酯酶(AChE)再生技术,研究AChE阳性神经元在鼠脑的分布和形态特征。按其染色程度,可见强度、中度和轻度三种染色细胞。强染色细胞多数是较大的多极细胞,主要分布于纹状体、基底前脑、下丘脑、黑质、红核、蓝斑,腹侧被盖区、臂旁核、桥被盖核和脑神经运动核。本文将AChE染色结果和胆碱乙酰转移酶(ChAT)免疫组织化学资料进行了比较,对AChE和胆碱能神经元的关系,以及AChE阳性神经元的性质和意义,进行了讨论。     

Genomic instability in scleroderma

Scleroderma is an enigmatic rheumatic disorder of uncertain etio-pathogenesis. Cancer has an approximately two-fold higher incidence in scleroderma patients than in the general population. There are preliminary data of acquired genetic damage in scleroderma but the significance of these observations are uncertain. To determine somatic mutation frequency at the glycophorin-A (GPA) locus in patients with limited and diffuse cutaneous scleroderma. The GPA assay measures the total somatic mutation frequency (Vf), composed of gene inactivating mutations (NO) and mutations arising from mitotic recombination (NN) in individuals heterozygous for the GPA MN blood group. Mutation frequency was determined using a validated GPA flow cytometric assay using fluorescent labeled monoclonal antibodies specific for the GPA blood groups M and N. This assay detects and enumerates progeny of red blood cell (rbc) precursor cells which have acquired genetic damage resulting in a loss of expression of one of the GPA alleles. It was found that patients with scleroderma (n = 23) had significantly elevated Vf as compared with young healthy controls (p < 0.001) and elderly controls (p = 0.03). Patients with diffuse scleroderma had higher mean Vf as compared with limited scleroderma (p = 0.055). In comparison with controls, patients with scleroderma exhibit a higher proportion of mitotic recombinant mutations than inactivating mutations (p < 0.002). There was no correlation between Vf and disease duration, age at onset or autoantibody status. We have documented evidence of acquired genetic damage at the GPA locus in scleroderma. Evidence of acquired genetic damage in this disorder may be importance in explaining both the etio-pathogenesis of scleroderma and the association of scleroderma with cancer.     

Attenuation of intracavitary applicators in 192Ir-HDR brachytherapy

Unlike the penetrating monoenergetic 662 keV gamma rays emitted by 137Cs LDR sources, the spectrum of 192Ir used in HDR brachytherapy contains low-energy components. Since these are selectively absorbed by the high-atomic number materials of which intracavitary applicators are made, the traditional neglect of applicator attenuation can lead to appreciable dose errors. We investigated the attenuation effects of a uterine applicator, and of a set of commonly used vaginal cylinders. The uterine applicator consists of a stainless steel source guide tube with a wall thickness of 0.5 mm and a density of 8.02 g/cm3, whereas the vaginal cylinders consist of the same stainless steel tube plus concentric polysulfone cylinders with a radius of 1 or 2 cm and a density of 1.40 g/cm3. Monte Carlo simulations were performed to compute dose distributions for a bare 192Ir-HDR source, and for the same source located within the applicators. Relative measurements of applicator attenuation using ion-chambers (0.125 cm3) confirmed the Monte Carlo results within 0.5%. We found that the neglect of the applicator attenuation overestimates the dose along the transverse plane by up to 3.5%. At oblique angles, the longer photon path within applicators worsens the error. We defined attenuation-corrected radial dose and anisotropy functions, and applied them to a treatment having multiple dwell positions inside a vaginal cylinder.     

抗慢性B淋巴细胞白血病患者IgM单抗相对亲和力的分析

本文采用间接ELISA法检测了11株抗B-CLL患者IgM腹水和杂交瘤上清McAb的相对亲和力。结果提示,各株McAb结合抗原的相对亲和力不同。根据50％最大结合浓度分为两组。其中4株杂交瘤上清McAb与纯化腹水McAb测得结果基本吻合。实验结果为合理地选用这些单抗提供了重要依据。     

Distinct types of T-cell help for the induction of a humoral immune response to Streptococcus pneumoniae

Studies have indicated that purified soluble polysaccharide antigens can elicit T cell-independent Ig responses in vivo, although these responses can be modulated by T cells in a noncognate manner. Relatively little is known, however, concerning the parameters that regulate polysaccharide-specific, as well as protein-specific, Ig isotype responses to an intact extracellular bacterium. Using the murine in vivo humoral response to intact Streptococcus pneumoniae as a model it can be shown that CD4+ T-cell receptor alphabeta+ T cells deliver help for both polysaccharide- and protein-specific Ig responses. However, these responses differ fundamentally in their mechanism of action.     

钾离子对体外培养中枢神经髓鞘形成的影响──一种新的体外培养中枢神经脱髓鞘模型的建立

本文应用组织培养和电镜等方法研究了ＫＣＩ对体外培养中枢神经系统髓鞘形成的影响。结果表明：体外培养Ｂ６Ｃ３小鼠小脑组织髓鞘形成的关键期是１０～１４ｄ，在１０～１２ｄ时体外培养的小脑组织对ＫＣＩ最为敏感；当培养液内ＫＣＩ浓度达到３０ｍｍｏｌ／Ｌ时，即可完全抑制髓鞘形成。本文对钾离子引起体外培养中枢神经组织脱髓鞘的机制进行了讨论。     

豚鼠脊髓运动神经元分支至股神经和腰背肌的研究——逆行荧光双标记法

应用碘化丙院-双苯甲亚胺配伍逆行荧光双标记技术对豚鼠脊髓运动神经元分支至股神经和腰背肌作了研究.结果发现股神经的运动纤维来源于同侧L1～5脊髓前角内侧核运动神经元和L4～5脊髓前角外侧核运动神经元;腰背肌的运动纤维来源于同侧相应节段脊髓前角内侧核运动神经元.在L3～5脊髓前角内侧核运动神经元中,有碘化丙啶-双苯甲亚胺荧光双标记运动神经元,占内侧核全部标记运动神经元的18.8‰.结果提示脊髓前角运动神经元具有分支分布至腰背肌和股神经的现象.