卵胞质移植、克隆与逆向克隆

目的:最近人类卵细胞间的胞质移植被作为人类辅助生殖生物技术的手段并成为研究热点。本文回顾了该领域的研究进展和存在的问题,并以此为基础提出“逆向克隆技术”这一新概念。资料来源:应用计算机检索PUBMED 1998-01/2006-12期间的相关文章,检索词为“ooplasmic transfer,mitochondria heteroplasmy,animal cloning”,并限定文章语言种类为English。同时计算机检索万方数据库1998-01/2006-12期间的相关文章,检索词为“胞质转移,线粒体异质性,动物克隆”,并限定文章语言种类为中文。资料选择:对资料进行初审,并查看每篇文献后的引文。纳入标准:文章所述内容应与卵胞质移植、克隆或逆向克隆研究相关。排除标准:重复研究或Meta分析类文章。资料提炼:共收集到126篇相关文献,31篇文献符合纳入标准,排除的95篇文献为内容陈旧或重复。符合纳入标准的31篇文献中,17篇涉及卵胞质移植,13篇涉及动物克隆,1篇涉及逆克隆。资料综合:人类的生殖技术领域发展迅速,卵胞质移植技术得到广泛应用。研究表明,卵胞质对受精和胚胎发育具有重要作用,其中线粒体与受精和胚胎发育关系最为密切。大量实验对细胞质与细胞核的相互作用、基因组的重编程机制上进一步研究,同时也在技术上不断改进。克隆技术有广阔的应用前景,同时也存在着不少问题,基于此提出以胞质转移为基础的“逆向克隆技术”。结论:线粒体对卵母细胞的受精和胚胎发育有显著影响,但卵胞质移植可能导致线粒体的异质性及其潜在的问题还需要进一步研究。以卵胞质转移为基础的“逆向克隆技术”是否能达到克隆动物的结果前景喜人。     

血管内皮生长因子对佐剂性关节炎滑膜细胞基质金属蛋白酶3及基质金属蛋白酶9表达的影响

目的:观察血管内皮生长因子对佐剂性关节炎滑膜细胞质金属蛋白酶3及质金属蛋白酶9表达的影响,并探讨其意义。方法:实验于2006-02/12在桂林医学院实验中心完成。①实验材料:清洁级8周龄雄性Wistar大鼠6只,血管内皮生长因子为Peprotech EC LTD公司产品,基质金属蛋白酶3(扩增369bp)上游引物、下游引物,基质金属蛋白酶9(扩增405bp)上游引物、下游引物均购自晶美公司。②实验干预:先用弗氏完全佐剂造Wistar大鼠模型;造模20d后取Wistar大鼠右后足滑膜细胞进行原代培养。③实验分组:实验分为血管内皮生长因子组:取P2代细胞接种于6孔培养板,分别加入终浓度为5,25,50μg/L血管内皮生长因子;对照组:不加血管内皮生长因子。④实验评估:取病理切片观察滑膜细胞形态学改变;采用半定量反转录聚合酶链反应检测Wistar大鼠佐剂性关节炎滑膜细胞基质金属蛋白酶3及基质金属蛋白酶9的m-RNA表达。结果:①培养细胞的形态学观察:原代培养14d滑膜细胞从组织块边缘逸出,21d密集生长开始传代;传代细胞48h可明显分辨出树突样细胞、巨噬细胞样细胞和成纤维细胞样细胞;传至21代,细胞生长及特性稳定。②病理切片:滑膜组织有中性粒细胞、单核细胞、淋巴细胞浸润,滑膜细胞增生、排列紊乱,纤维素渗出,胶原纤维沉着,纤维素样坏死,呈滑膜炎表现。③基质金属蛋白酶3、基质金属蛋白酶9的mRNA表达:对照组基质金属蛋白酶3mRNA表达相对灰度值与血管内皮生长因子终浓度5,25,50μg/L组比较,差异有显著性意义(0.32±0.03,0.77±0.06,1.12±0.12,1.59±0.02,P<0.05);对照组基质金属蛋白酶9mRNA表达相对灰度值与血管内皮生长因子终浓度5,25,50μg/L组比较,差异有显著性意义(0.47±0.07,0.50±0.10,0.91±0.10,1.31±0.06,P<0.05);基质金属蛋白酶3和基质金属蛋白酶9mRNA表达随血管内皮生长因子浓度的加大表达增加。结论:血管内皮生长因子以剂量递增的方式对体外培养的佐剂性关节炎滑膜细胞基质金属蛋白酶3及基质金属蛋白酶9的表达有促进作用。     

The effect of diabetes mellitus on the association between measures of glycaemic control and ICU mortality: a retrospective cohort study

Introduction

In critical illness, four measures of glycaemic control are associated with ICU mortality: mean glucose concentration, glucose variability, the incidence of hypoglycaemia (≤ 2.2 mmol/l) or low glucose (2.3 to 4.7 mmol/l). Underlying diabetes mellitus (DM) might affect these associations. Our objective was to study whether the association between these measures of glycaemic control and ICU mortality differs between patients without and with DM and to explore the cutoff value for detrimental low glucose in both cohorts.

Methods

This retrospective database cohort study included patients admitted between January 2004 and June 2011 to a 24-bed medical/surgical ICU in a teaching hospital. We analysed glucose and outcome data from 10,320 patients: 8,682 without DM and 1,638 with DM. The cohorts were subdivided into quintiles of mean glucose and quartiles of glucose variability. Multivariable regression models were used to examine the independent association between the four measures of glycaemic control and ICU mortality, and for defining the cutoff value for detrimental low glucose.

Results

Regarding mean glucose, a U-shaped relation was observed in the non-DM cohort with an increased ICU mortality in the lowest and highest glucose quintiles (odds ratio = 1.4 and 1.8, P < 0.001). No clear pattern was found in the DM cohort. Glucose variability was related to ICU mortality only in the non-DM cohort, with highest ICU mortality in the upper variability quartile (odds ratio = 1.7, P < 0.001). Hypoglycaemia was associated with ICU mortality in both cohorts (odds ratio non-DM = 2.5, P < 0.001; odds ratio DM = 4.2, P = 0.001), while low-glucose concentrations up to 4.9 mmol/l were associated with an increased risk of ICU mortality in the non-DM cohort and up to 3.5 mmol/l in the DM cohort.

Conclusion

Mean glucose and high glucose variability are related to ICU mortality in the non-DM cohort but not in the DM cohort. Hypoglycaemia (≤ 2.2 mmol/l) was associated with ICU mortality in both. The cutoff value for detrimental low glucose is higher in the non-DM cohort (4.9 mmol/l) than in the DM cohort (3.5 mmol/l). While hypoglycaemia (≤ 2.2 mmol/l) should be avoided in both groups, DM patients seem to tolerate a wider glucose range than non-DM patients.     

中国西南地区汉族人群肿瘤坏死因子基因多态性与鼻咽癌遗传易感性

目的:分析肿瘤坏死因子基因多态性分布与中国西南地区汉族人群鼻咽癌易感性的关系。方法:选择2000-10/2005-09在华西医科大学第一附属医院就诊的100例鼻咽癌患者为鼻咽癌组,均经过病理科活检确诊,其中包括未治疗44例,放疗后37例,放疗加化疗后19例,选择100名同期入院健康体检者为对照组。所有受试对象为中国西南地区汉族人,均对检测项目知情同意。采用聚合酶链反应-限制性片段长度多态性的方法检测100例中国西南地区汉族鼻咽癌患者和100名健康对照者肿瘤坏死因子α基因启动子区-308位点及肿瘤坏死因子β基因第一内含子252位点的等位基因以及基因型频率,分析两位点多态性与鼻咽癌遗传易感性的关系。结果:鼻咽癌组患者肿瘤坏死因子β( 252)位点G/A杂合子基因型频率显著高于对照组(57%,29%,P<0.01),野生型(G/G基因型)频率低于健康对照组(23%,51%,P<0.01),等位基因A的频率高于健康对照组(48.5%,13%,P<0.01);肿瘤坏死因子α(-308)位点基因型以及等位基因频率与对照组相比较无统计学差异。结论:本实验人群中未发现肿瘤坏死因子α(-308)位点多态性与鼻咽癌易感性无关;肿瘤坏死因子β( 252)位点基因多态性与鼻咽癌具有相关性,A等位基因可能是鼻咽癌的遗传易感基因,G/A杂合子基因型个体较易患鼻咽癌。     

Temporal fluctuations in coherence of brain waves.

As a measure of dynamical structure, short-term fluctuations of coherence between 0.3 and 100 Hz in the electroencephalogram (EEG) of humans were studied from recordings made by chronic subdural macroelectrodes 5-10 mm apart, on temporal, frontal, and parietal lobes, and from intracranial probes deep in the temporal lobe, including the hippocampus, during sleep, alert, and seizure states. The time series of coherence between adjacent sites calculated every second or less often varies widely in stability over time; sometimes it is stable for half a minute or more. Within 2-min samples, coherence commonly fluctuates by a factor up to 2-3, in all bands, within the time scale of seconds to tens of seconds. The power spectrum of the time series of these fluctuations is broad, extending to 0.02 Hz or slower, and is weighted toward the slower frequencies; little power is faster than 0.5 Hz. Some records show conspicuous swings with a preferred duration of 5-15s, either irregularly or quasirhythmically with a broad peak around 0.1 Hz. Periodicity is not statistically significant in most records. In our sampling, we have not found a consistent difference between lobes of the brain, subdural and depth electrodes, or sleeping and waking states. Seizures generally raise the mean coherence in all frequencies and may reduce the fluctuations by a ceiling effect. The coherence time series of different bands is positively correlated (0.45 overall); significant nonindependence extends for at least two octaves. Coherence fluctuations are quite local; the time series of adjacent electrodes is correlated with that of the nearest neighbor pairs (10 mm) to a coefficient averaging approximately 0.4, falling to approximately 0.2 for neighbors-but-one (20 mm) and to < 0.1 for neighbors-but-two (30 mm). The evidence indicates fine structure in time and space, a dynamic and local determination of this measure of cooperativity. Widely separated frequencies tending to fluctuate together exclude independent oscillators as the general or usual basis of the EEG, although a few rhythms are well known under special conditions. Broad-band events may be the more usual generators. Loci only a few millimeters apart can fluctuate widely in seconds, either in parallel or independently. Scalp EEG coherence cannot be predicted from subdural or deep recordings, or vice versa, and intracortical microelectrodes show still greater coherence fluctuation in space and time. Widely used computations of chaos and dimensionality made upon data from scalp or even subdural or depth electrodes, even when reproducible in successive samples, cannot be considered representative of the brain or the given structure or brain state but only of the scale or view (receptive field) of the electrodes used. Relevant to the evolution of more complex brains, which is an outstanding fact of animal evolution, we believe that measures of cooperativity are likely to be among the dynamic features by which major evolutionary grades of brains differ.     

Bone loss and avascular necrosis of bone after hematopoietic cell transplantation

Advances in transplantation technology and supportive care measures have resulted in significant decrease in early mortality resulting in continued growth in the number of long-term hematopoietic cell transplantation (HCT) survivors. The intensity of chemotherapy and total body irradiation regimen used pretransplantation to eradicate the primary disease can lead to organ toxicities, including significant bone complications after HCT. Bone loss is frequent in HCT recipients and results from impaired bone mineralization through disturbances of calcium and vitamin D homeostasis, osteoblast and osteoclast dysfunction, and deficiencies in growth or gonadal hormone secretion. Exposure to glucocorticoids and calcineurin inhibitors for prevention and treatment of graft-versus-host disease (GVHD) represents one of the major causes for the increased risk of osteoporosis and avascular necrosis of bone (AVN) in recipients of allogeneic HCT. In this article we review the incidence, pathogenesis, and risk factors for osteoporosis and AVN after allogeneic HCT and discuss general guidelines for their treatment and monitoring based on the limited available reports.