Maize NDC80 is a constitutive feature of the central kinetochore

In yeast and animals, Nuclear Division Cycle 80 (NDC80) is an important kinetochore protein that binds to microtubules and mediates chromosome movement. Its localization pattern is unusual, since it is generally not viewed as either an inner (centromeric chromatin) or outer (regulatory) component of the kinetochore. Here we report the characterization of NDC80 in a higher plant. By taking advantage of the large meiotic kinetochores of maize, we were able to show that NDC80 localizes outside of the constitutive kinetochore protein CENP-C. Further, a detailed analysis of mitosis indicates that NDC80 is stably present on kinetochores throughout the cell cycle. The quantity of NDC80 positively correlates with measured quantities of DNA and CENP-C, suggesting that NDC80 rapidly associates with DNA following replication and is stably maintained at centromeres during cell division. The data suggest that in plants NDC80 is on par with ‘foundation’ kinetochore proteins such as CENH3 and CENP-C.     

Global gene expression and the role of sigma factors in Neisseria gonorrhoeae in interactions with epithelial cells

Like many bacterial pathogens, Neisseria gonorrhoeae must adapt to environmental changes in order to successfully colonize and proliferate in a new host. Modulation of gene expression in response to environmental signals is an efficient mechanism used by bacteria to achieve this goal. Using DNA microarrays and a tissue culture model for gonococcal infection, we examined global changes in gene expression in N. gonorrhoeae in response to adherence to host cells. Among those genes induced upon adherence to human epithelial cells in culture was rpoH, which encodes a homolog of the heat shock sigma factor, sigma(32) (RpoH), as well as genes of the RpoH regulon, groEL and groES. Attempts to construct an rpoH null mutant in N. gonorrhoeae were unsuccessful, suggesting that RpoH is essential for viability of N. gonorrhoeae. The extracytoplasmic sigma factor, RpoE (sigma(E)), while known to regulate rpoH in other bacteria, was found not to be necessary for the up-regulation of rpoH in gonococci upon adherence to host cells. To examine the role of RpoH in host cell interactions, an N. gonorrhoeae strain conditionally expressing rpoH was constructed. The results of our experiments showed that while induction of rpoH expression is not necessary for adherence of gonococci to epithelial cells, it is important for the subsequent invasion step, as gonococci depleted for rpoH invade cells two- to threefold less efficiently than a wild-type strain. Taken together, these results indicate that sigma(32), but not sigma(E), is important for the response of gonococci in the initial steps of an infection.     

Recurrent chromosome changes in 62 primary gastric carcinomas detected by comparative genomic hybridization

Comparative genomic hybridization (CGH) has been applied to detect recurrent chromosome alterations in 62 primary gastric carcinomas. Several nonrandom chromosomal changes, including gains of 8q (31 cases, 50%), 20q (29 cases, 47%) with a minimum gain region at 20q11. 2-q12, 13q (21 cases, 34%) with a minimum gain region at 13q22, and 3q (19 cases, 31%) were commonly observed. The regions most frequently lost included: 19p (23 cases, 37%), 17p (21 cases, 33%), and 1p (14 cases, 23%). High copy number gain (DNA sequence amplification) was detected in 6 cases. Amplification of 8q23-q24.2 and 20q11.2-q12 were observed in 3 cases. Gain of 20q and loss of 19p were confirmed by fluorescence in situ hybridization using corresponding bacterial artificial chromosomes (BAC) clones from those regions. The gain and loss of chromosomal regions identified in this study provide candidate regions involved in gastric tumorigenesis.     

Functional disomies of the X chromosome influence the cell selection and hence the X inactivation pattern in females with balanced X-autosome translocations: a review of 122 cases.

We reviewed 122 cases of balanced X-autosome translocations in females, with respect to the X inactivation pattern, the position of the X break point and the resulting phenotype. In 77% of the patients the translocated X chromosome was early replicating in all cells analysed. The break points in these cases were distributed all along the X chromosome. Most of these patients were either phenotypically normal or had gonadal dysgenesis, some had single gene disorders, and less than 9% had multiple congenital anomalies and/or mental retardation. In the remaining 23% of the cases the translocated X chromosome was late replicating in a proportion of cells. In these cells only one of the translocation products was reported to replicate late, while the remaining portion of the X chromosome showed the same replication pattern as the homologous part of the active, structurally normal X chromosome. The analysis of DNA methylation in one of these cases confirmed noninactivation of the translocated segment. Consequently, these cells were functionally disomic for a part of the X chromosome. The presence of disomic cells was highly prevalent in translocations with break points at Xp22 and Xq28, even though spreading of X inactivation onto the adjacent autosomal segment was noted in most of these cases. This suggests that selection against cells with a late replicating translocated X is driven predominantly by a functional disomy X, and that the efficiency of this process depends primarily on the position of the X break point, and hence the size of the noninactivated region.(ABSTRACT TRUNCATED AT 250 WORDS)     

Early treatment with ganciclovir to prevent cytomegalovirus disease after allogeneic bone marrow transplantation.

BACKGROUND. Cytomegalovirus (CMV) infection is a major cause of morbidity and mortality after allogeneic bone marrow transplantation. We conducted a controlled trial of ganciclovir for the early treatment of CMV infection in asymptomatic recipients of bone marrow transplants whose surveillance cultures for CMV became positive. METHODS. Bone marrow--allograft recipients who were seropositive for CMV antibodies or who received seropositive marrow were screened for CMV excretion by culture of throat swabs, blood, urine, or bronchoalveolar-lavage fluid. In this double-blind trial, 72 patients who had marrow engraftment and were excreting virus were randomly assigned to receive either placebo or ganciclovir (5 mg per kilogram of body weight twice a day for one week, followed by 5 mg per kilogram per day) for the first 100 days after transplantation. Patients were followed for the development of biopsy-confirmed CMV disease, ganciclovir-related toxicity, and survival. RESULTS. Between assignment to the study drug and day 100 after transplantation, CMV disease developed in only 1 of the 37 patients assigned to receive ganciclovir (3 percent), but in 15 of the 35 patients assigned to receive placebo (43 percent, P less than 0.00001). The ganciclovir recipients had rapid suppression of virus excretion; 85 percent had negative cultures after one week of treatment, as compared with 44 percent of the placebo group (P = 0.001). The principal toxic reaction was neutropenia; 11 ganciclovir recipients had an absolute neutrophil count below 0.75 x 10(9) per liter, as compared with 3 placebo recipients (P = 0.052). Treatment was discontinued in 11 ganciclovir recipients and 1 placebo recipient because of neutropenia (P = 0.003). After treatment was stopped, the neutrophil count recovered in all patients. Overall survival was significantly greater in the ganciclovir group than in the placebo group both 100 days and 180 days after transplantation (P = 0.041 and 0.027, respectively). CONCLUSIONS. Early treatment with ganciclovir in patients with positive surveillance cultures reduces the incidence of CMV disease and improves survival after allogeneic bone marrow transplantation.     

白细胞介素1刺激破骨细胞性骨吸收作用的实验研究

目的：了解白细胞介素1β（IL－1β）在破骨细胞性骨吸收中的刺激作用及其相应的作用机制。方法：分别将新生大鼠破骨细胞单独以及和成骨细胞联合接种于预置象牙片的培养板中。24h后培养液中加入不同浓度的IL－1β。继续培养48h,然后取出象牙片,超声处理后行甲苯胺蓝染色,光镜下观察骨吸收陷窝的数目并计算其部面积。结果：IL－1β能够明显增加坡骨细胞和成骨细胞联合培养组象牙片上吸收陷窝的数目和面前,且刺激作用呈剂量依赖性,但对单独培养的破骨细胞无明显刺激作用。结论：IL－1β的刺激骨吸收作用由成骨细胞所介导,而非直接作用于破骨细胞。     

小儿再发性腹痛的病因学分析

目的 分析小儿再发性腹痛的病因以及相关的因素为临床选择辅助检查及诊断提供依据或参考。方法 268例再发性腹痛患儿选人调查对象,对其进行病因学调查,调查内容包括年龄、性别、季节、诱因、部位等8个因素,进行分析。选择相关的辅助检查确定病因。结果 有52例有器质性疾病(19．4％),以慢性胃炎居首位。与发作有关的因素有季节、年龄、情绪反应。结论 小儿再发性腹痛绝大多数属于功能性疾病,只有少数由器质性原因引起,但仍应引起足够重视,谨慎的选择辅助检查,避免漏诊。     

海南省琼中县高疟区应用磷酸萘酚喹控制疟疾的效果

目的 评估在较大的范围内使用磷酸萘酚喹控制疟疾的效果,为今后该药用于控制疟疾提供依据。方法 在季节性抗疟控制传染源的用药上,对春季和秋季抗疟的集体服药村庄,一律使用磷酸萘酚喹一天疗法,代替哌喹 防Ⅱ 伯喹两天疗法,从首次服药的第七天起,由卫生院防保人员和村医,每隔七天到各村巡诊,发现“四热”病人采血送检,掌握用药前后的疫情动态。结果 据疫情报告统计,2000年全年“四热”血检率达10％以上,血检阳性率0．62％、居民带虫率0．05％、年带虫发病率(API)1．5‰,与1999年对比,分别下降55．83％、93．93％、33．78％,发病村(队)由1999年的180个减至109个,减少39．44％,且无明显副反应。结论 琼中县高疟区居民集体服药使用磷酸萘酚喹控制疟疾流行效果较为显,值得继续应用作进一步的评估。     

人工机械瓣膜替换术后早期并发症分析

1987年1月至2000年4月,共施行人工机械瓣膜替换手术700例,其中二尖瓣替换术398例,主动脉瓣替换术81例,二尖瓣和主动脉瓣替换术213例,三尖瓣替换术8例.158例患者术中和术后早期发生并发症,发生率为22.6%,死亡44例,死亡率6.3%.死亡原因主要为低心排出量综合征、严重感染和心律失常等.     

p16、p15蛋白在小儿急性淋巴细胞白血病的表达及临床相关性研究

目的：探讨p16、p15蛋白在急性淋巴细胞白血病（ALL）发病中的意义。方法：对23例ALL细胞进行间接免疫荧光染色,用流式细胞仪检测细胞的荧光强度,间接反映p16、p15蛋白水平。结果：23例ALL患儿p16蛋白阴性10例,p15蛋白阴性8例,p16、p15蛋白均阴性6例。3例T－ALL中p16、p15蛋白皆阴性2例,13例Non T-ALL中,p16蛋白阴性6例,p15蛋白阴性5例。高白细胞组的p16、p15蛋白表达阳性率低于非高白细胞组,差异有显著意义（P＜0．05）,HR－ALL组p16、p15蛋白阳性表达低于SR－ALL组,差异有显著意义（P＜0．05）。结论：p16、p15蛋白参与了部分急性淋巴细胞白血病的发病,p15、p15蛋白阴性的患者可能预后不良。