克隆缺失连接片段——一种基于PCR技术的缺失型假肥大型肌营养不良症的携带者检测

目的 依据dystrophin基因缺失后断端重接可形成一段变异的DNA序列,提出一种利用缺失连接片段进行缺失型假肥大型肌营养不良症携带者检测的新方法.方法 实验以来自广东省肇庆地区的一个Becker型肌营养不良(Becket muscular dystrophy,BMD)家系为研究对象,其中2例确诊的男性BMD患者,3例待诊的女性携带者,1例待诊的人工流产绒毛.先证者经外显子PCR检测确定第3～5外显子缺失,随后采用PCR步移法在相应内含子设计引物定位断裂点的位点,最后利用靠近断裂点设计的引物直接对家系的6例基因组DNA进行缺失连接片段的PCR扩增和测序.结果 6例基因组DNA均扩增出阳性的产物片段且连接片段的测序序列完全一致,绒毛的性别诊断结果为女性,可以确诊本家系中的3个女性和流产绒毛均为缺失型BMD携带者.结论 作者成功地将整个家系患者和携带者的缺失连接片段进行克隆和测序分析,实现了利用缺失连接片段对缺失型假肥大型肌营养不良症携带者进行准确基因诊断的设想,同时对在产前诊断上的应用前景进行了探讨.     

Transplantation of hematopoietic stem cells for induction of unresponsiveness to organ allografts

Although it has been recognized since the early days of Owen and Medawar that engraftment of donor stem cells, induced in utero spontaneously or intentionally neonatally, results in life-long unresponsiveness to donor alloantigens. However, successful induction of transplantation tolerance in adult life still represents an unsolved problem. Engraftment of donor stem cells using conventional modalities involves intensive myeloablative or lymphoablative immunosuppression, which is associated with toxicity and mortality and such methods are not suitable for organ allograft recipients. In this chapter, we present an innovative approach for induction of donor-specific unresponsiveness to bone marrow and organ allografts without myeloablative conditioning. Our methods is based on cyclophosphamide-induced, alloantigen-primed lymphocyte depletion. Cyclophosphamide is administered 1 day following infusion of donor hematopoietic cells, thus eliminating predominantly host T lymphocytes reacting against donor cell challenge, and resulting in relative unresponsiveness to donor alloantigens. Subsequently, life-long tolerance to fully mismatched donor skin allografts can be accomplished by a second infusion of stem cells from the same donor, with donor T cells displacing residual alloreactive host cells that may have escaped deletion. Taken together, we believe that induction of true permanent and specific tolerance to organ allografts using donor hematopoietic cells could become a clinical reality in the foreseeable future.     

Pericentric inversions of chromosome 4: report of a new family and review of the literature

A family was cytogenetically studied because of the birth of a male child with a multiple congenital anomaly pattern, in whom a dup (4q) recombinant was found. His phenotypically normal mother's karyotype showed an apparently balanced pericentric inversion in a chromosome 4. So as to analyze the occurrence of recombinants, the cytogenetic data from this family are compared with those of the 18 previously reported familial cases of pericentric inversions (PIs) of chromosome 4. The congenital anomalies observed in the child strongly suggest Wolf-Hirschhorn syndrome but some of his clinical features seem to be pathogenetically related to the presence of lymphedema during the intrauterine period. In the multiple congenital anomaly pattern observed in this patient, the lymphedema could be the consequence of the large 4q duplication. The review of chromosome 4 PIs with 4q duplication suggests that the q3 region should be examined when edema is detected prenatally.     

Familial translocation t(10;14) (q26.1;q32.3): report of three offspring with 10q deletion and 14q duplication

We describe two brothers and a cousin with common clinical features, including mild mental retardation, motor delays, hypotonia with truncal ataxia, esotropia, and mild facial and hand dysmorphia. The initial routine chromosome study failed to detect any abnormality in the proband. Based on a high index of clinical suspicion, high-resolution chromosome studies were performed on the proband's parents. A small reciprocal translocation t(10;14) (q26.1;q32.3) was detected in the father. The breakpoint on the derivative chromosome 14 was further placed telomeric to the immunoglobulin heavy-chain gene cluster at the band q32.33 by fluorescence in situ hybridization. Studies of the proband and two affected paternal cousins revealed that each had inherited the same derivative chromosome 10 from their carrier parents. This unbalanced karyotype resulted from an adjacent-1 segregation of the 10;14 translocation.     

Absence of peripheral clonal deletion and anergy in immune responses of T cell-reconstituted athymic mice

Superantigens induce clonal deletion of reactive T cells in the thymus and clonal deletion and anergy in the periphery of euthymic mice. In this report we have assessed the ability of Staphylococcal enterotoxin B (SEB) to induce peripheral tolerance in nude mice reconstituted with normal, syngeneic T cells. Immunization of reconstituted nude mice with SEB resulted in lethal toxic shock in a large fraction of the animals. Such lethality was never observed in the normal donor mouse strain. Analysis of lymphokine production in response to SEB showed that reconstituted nude mice produced higher levels of interleukin-2 and tumor necrosis factor-α, but lower levels of interleukin-4, than euthymic control mice. Furthermore, SEB was unable to promote either clonal elimination or induction of anergy in the SEB-responsive peripheral T cells, despite the fact that reconstituted nude mice did produce high levels of corticosterone upon treatment with SEB. These results imply a lack of control over immune responses to superantigen in T cell-reconstituted athymic mice.     

A case of de novo interstitial deletion of chromosome 9(p12p13)

The present paper describes a girl with a small de novo deletion of chromosome 9(p12p13). This deletion has not been published previously. The deleted fragment is clearly outside the region involved in the so-called deletion 9p syndrome. The patient had mild dysmorphic features and feeding problems during the first weeks of life, but is now developing well. Because of the lack of severe clinical features in this patient, we speculate that the deletion may be prevalent in other patients who have no clinical indication for chromosome investigation.     

Saethre‐Chotzen syndrome and hyper IgE syndrome in a patient with a novel 11 bp deletion of the TWIST gene

Molecular genetic studies in a seven‐year‐old boy and his mother demonstrated a novel 11 bp deletion in the TWIST gene (127del11), causing Saethre‐Chotzen syndrome. The mother had rather mild signs of the Saethre‐Chotzen syndrome; however, her son presented with marked acrocephalosyndactyly type 3, leading to craniotomy at three years. He also had recurrent infections and laboratory findings comparable with the hyper IgE syndrome, a rare primary immunodeficiency disorder. It is likely that the 11bp deletion caused the Saethre‐Chotzen syndrome in the patient and his mother, and another, not yet identified genetic defect, seen in the patient but not in the mother, is responsible for the hyper IgE phenotype. A combination of these two congenital conditions has not been described to date. © 2001 Wiley‐Liss, Inc.     

Mitochondrial DNA content and 4977 bp deletion in unfertilized oocytes

Previous studies analysing the incidences of mitochondrial DNA (mtDNA) deletions and mtDNA content in unfertilized oocytes in relation to donors' age have been controversial. The objective of the study was to compare these two parameters in unfertilized oocytes and relate them to the donors' age. Fifty-two women donated 155 unfertilized metaphase II (MII) oocytes. The incidence of 4977 bp deletion was 34.6%, and the mtDNA copy number was 598 350 +/- 265 862. Women >or=35 years of age had a significantly higher incidence of 4977 bp deletion, lower mtDNA copy number, higher FSH level and poorer ovarian response when compared with younger women. The mtDNA copy number was negatively correlated with the donor's age. The higher incidence of mtDNA deletion and lower mtDNA copy number in older women suggested that these two parameters may reflect ovarian ageing.     

Interstitial deletion in the long arm of chromosome no. 5

A case of a male infant with several congenital anomalies combined with an interstitial deletion of the long arm of chromosome no. 5 is presented. The symptoms of the infant were compared to five previous reported cases with similar interstitial deletions in 5q.     

HCV NS3 N末端部分氨基酸缺失对NS3/NS3与NS3/NS4A分子间相互作用的影响

目的旨在弄清ＮＳ３参与分子间相互作用的确切区段，为研究针对ＮＳ３的抗ＨＣＶ寡肽小分子药物的设计提供依据。方法参照ＨＣＶ中国河北株序列设计ＮＳ３引物，将其Ｎ末端的前１５个和前３０个氨基酸分别缺失掉。然后用酵母双杂交系统检测ＮＳ３／ＮＳ３及ＮＳ３／ＮＳ４Ａ分子间相互作用强度在缺失前后的变化，从而判明ＮＳ３Ｎ末端氨基酸在分子间相互作用中的意义。核苷酸序列分析采用ＡｐｐｌｉｅｄＢｉｏｓｙｓｔｅｍ３７３Ａ型自动测序仪。结果ＮＳ３Ｎ末端氨基酸缺失前后，ＮＳ３／ＮＳ３分子间及ＮＳ３／ＮＳ４Ａ分子间相互作用的强度相差有显著性（Ｐ＜０．０１），但缺失１５个氨基酸和缺失３０个氨基酸对上述相互作用强度的影响差异无显著性（Ｐ＞０．０５）。结论ＮＳ３Ｎ末端的１～３０个氨基酸在ＮＳ３／ＮＳ３及ＮＳ３／ＮＳ４Ａ分子间相互作用中有一定意义，其Ｎ末端前１５个氨基酸（ＡＰＩＴＡＹＳＱＱＴＲＧＬＬＧ）对于分子间相互作用更为关键。本研究结果将为抗ＮＳ３丝氨酸蛋白酶活性的寡肽抑制物的研究打下基础，并为抗ＨＣＶ的寡肽小分子药物的设计提供依据