2型糖尿病大鼠骨折愈合障碍与体内晚期糖基化终末产物的变化

背景：近年来,晚期糖基化终末产物在骨组织领域的作用日益受到重视,而糖代谢紊乱是引起晚期糖基化终末产物增加的主要原因之一。 目的：观察2型糖尿病大鼠体内晚期糖基化终末产物表达的变化,并探讨其与糖尿病骨折愈合障碍的关系。 方法：30只SD大鼠随机均分为2组,实验组制备2型糖尿病模型,对照组正常饲养。糖尿病模型制备成功后,所有大鼠建立左胫骨骨折牵引成骨模型,胫骨延长0.3 mm/d,持续14 d。 结果与结论：牵引结束后,X射线摄片显示实验组糖尿病模型大鼠骨折断端之间牵引骨痂形成较对照组明显减少;骨痂组织学检查表现为微骨柱排列紊乱,初始基质前沿浅染。ELISA法检测实验组血清和双侧骨痂组织中晚期糖基化终末产物水平较对照组明显升高(P < 0.01),骨钙素明显降低(P < 0.01)。提示2型糖尿病大鼠骨折牵引骨痂生成障碍,而骨组织中晚期糖基化终末产物水平增高可能是导致2型糖尿病骨折愈合障碍的原因。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

糖尿病大鼠骨折愈合早期局部骨痂组织中Ⅰ型胶原纤维表达和骨密度的变化

背景：糖尿病患者骨折愈合过程中局部骨痂形成较差,成骨细胞增殖能力下降,骨折延迟愈合或者不愈合,而Ⅰ型胶原纤维和钙质成分是骨痂的主要成分。 目的：观察糖尿病大鼠骨折愈合早期过程中骨痂组织中Ⅰ型胶原纤维含量和骨密度的变化,分析糖尿病大鼠骨折愈合过程中骨折延迟愈合,或者不愈合的原因。 方法：10只腹腔内注射链脲佐菌素破坏胰岛细胞诱导为糖尿病大鼠,10只为正常对照大鼠,腹腔内注射等容量生理盐水。2组大鼠均造成右胫骨斜形骨折,于伤后第1,2,4,6周取骨痂组织进行检测。 结果与结论：正常对照组X射线片显示骨痂生成量多,骨折愈合程度明显优于模型对照组(P < 0.01),各组Ⅰ型胶原纤维表达均呈上升趋势,在第2周达到峰值,第4周下降,至第6周进一步下降。模型对照组骨痂中Ⅰ型胶原纤维表达和骨密度升高幅度明显低于正常对照组(P < 0.01)。提示糖尿病大鼠骨折愈合过程中较正常大鼠骨痂生成下降,骨痂中Ⅰ型胶原纤维表达和骨密度升高幅度同步下降。     

仙灵骨葆对骨质疏松性骨折骨痂血管形成的影响

背景：骨质疏松对骨折愈合早期的影响尚存争议,仙灵骨葆对骨质疏松性骨折愈合的影响及其机制尚有待深入研究。 目的：观察骨质疏松对大鼠股骨干骨折愈合的影响,以及仙灵骨葆对骨质疏松性骨折愈合的作用。 方法：将50只雌性12周龄Sprague-Dawley大鼠随机分成5组：假手术组、骨折组、去卵巢组、去卵巢+骨折组及治疗组,后3组切除大鼠双侧卵巢制备去卵巢模型,骨折模型于去卵巢后4周制备,为股骨干中段横行骨折。治疗组在去卵巢及骨折基础上灌胃给予仙灵骨葆250 mg/(kg•d)。给药3周,取去卵巢+骨折组、骨折组和治疗组大鼠骨折侧标本行X射线摄像仪摄片后,测量其骨密度,苏木精-伊红染色观察骨痂组织的病理学改变并计数血管,免疫组织化学染色检测骨痂组织骨形态发生蛋白2的表达。 结果与结论：去卵巢处理后大鼠的骨密度、计算机X射线摄像仪摄片评分显著降低(P < 0.05),仙灵骨葆可在一定程度上提高去卵巢后骨折大鼠的骨密度及X射线摄像仪摄片评分,但差异无显著性意义(P > 0.05);仙灵骨葆可提高去卵巢后骨折大鼠骨痂组织的血管数量(P < 0.05),但对骨形态发生蛋白2的表达无影响。提示,去卵巢后大鼠骨折早期愈合过程延迟,仙灵骨葆可促进骨质疏松大鼠骨折愈合早期血管的形成。     

卵巢切除股骨骨折大鼠骨愈合中降钙素的作用

背景：降钙素可活化腺苷酸环化酶蛋白激酶A通路及磷脂酶C通路,抑制破骨细胞的活性,可能治疗骨质疏松性骨折。 目的：观察降钙素对去卵巢大鼠股骨骨折愈合的作用。 方法：构建双侧卵巢切除骨质疏松右股骨骨折SD大鼠模型,然后分别皮下注射生理盐水和降钙素(16 IU/kg),隔日1次,于骨折后3周和6周测量右股骨行骨密度,苏木精-伊红及抗酒石酸酸性磷酸酶染色,骨形态发生蛋白2及血管内皮生长因子免疫组化染色。 结果与结论：骨折后给予降钙素治疗的大鼠抗酒石酸酸性磷酸酶染色阳性细胞积分吸光度值较生理盐水治疗的大鼠显著减少(P < 0.05)。骨折后3周,两组骨折线均较清晰,骨痂体积无明显差别,骨折愈合以软骨内化骨过程为主,骨密度无显著性差异(P > 0.05)。骨折后6周,两组骨折线较模糊,骨痂体积无差别,骨小梁排列较有序,用药组股骨骨密度较对照组升高(P < 0.05)。两组在骨折后3周和6周的骨形态发生蛋白2及血管内皮生长因子差异无显著性意义(P > 0.05)。证实降钙素可以抑制去卵巢大鼠骨折部位破骨细胞活性,但无明显促进大鼠股骨骨折愈合的作用。     

骨折局部注射结缔组织生长因子后骨保护素和血管内皮生长因子的表

背景：研究发现结缔组织生长因子在软骨发育过程中起重要作用,并具有强烈的促血管增殖作用,但其对骨折愈合的影响尚不清楚。 目的：观察局部注射结缔组织生长因子对骨折愈合过程中骨保护素和血管内皮生长因子表达的影响及作用机制。 方法：40只SD大鼠随机分为2组,建立胫骨干骨折模型后实验组动物即刻在骨折断端注射结缔组织生长因子0.1 μg/kg,对照组注射等量生理盐水,隔日1次。 结果与结论：实验组骨痂组织的早期即可见大量软骨细胞;免疫组织化学染色显示实验组骨保护素和血管内皮生长因子的表达均较对照组明显增强(P < 0.05),并且两者表达的高峰期与对照组相比有所延长,有效缩短了两者表达高峰期之间的时间间隔。提示局部注射外源性生长因子结缔组织生长因子能增加骨折愈合过程中骨保护素和血管内皮生长因子在骨痂组织中的表达,并能改变两者的表达高峰期进而促进骨折愈合。     

淫羊藿及骨形态发生蛋白2与家兔的骨折愈合

背景：淫羊藿是防治骨质疏松症的中药,但对骨折愈合的治疗尚缺乏依据。 目的：观察中药淫羊藿对家兔骨折愈合的作用。 方法：建立家兔单侧桡骨3 mm骨折动物模型,随机将其分为空白组、对照组和实验组。空白组予生理盐水灌胃加骨折局部注射生理盐水,实验组予中药淫羊藿熬制液灌胃加骨折局部注射生理盐水,对照组予生理盐水灌胃加骨折局部注射骨形态发生蛋白2。在术后2,4,8周,每组各取4只兔子通过X射线摄片、骨密度测定、生物力学测试(仅8周时)以及组织切片等评价骨折愈合的程度。 结果与结论：在各个时期段,X射线摄片显示实验组和对照组在骨痂的形成、改建及髓腔再通等均比空白组要好。实验组骨密度均优于空白组(P < 0.05),实验组和对照组之间差异无显著性意义(P > 0.05)。实验组生物力学性能优于空白组(P < 0.05),对照组数值介于两者之间。实验组和对照组在胶原纤维、软骨组织、骨小梁及骨基质的形成时期均早于空白组,实验组和对照组之间无显著性差异。提示淫羊藿能促进家兔骨折愈合。     

合并中枢神经损伤骨折愈合过程中胰岛素样生长因子Ⅰ的作用

背景：胰岛素样生长因子Ⅰ由成骨细胞合成,并对成骨细胞具有促进增殖和分化作用。 目的：观察中枢神经损伤对胰岛素样生长因子Ⅰ在血清、局部骨痂的表达及骨折愈合的影响。 方法：取Wistar大鼠随机分成正常对照组、脑损伤-骨折组、脊髓损伤-骨折组、单纯骨折组。于术后第1,2,3周测量血清中胰岛素样生长因子Ⅰ水平;术后第2,3周行X射线摄片评估骨痂愈合情况,术后1,2,3,4周取股骨制作标本,测量骨痂体积,术后3 d,1,2周免疫组织化学染色法检测骨痂局部胰岛素样生长因子Ⅰ的表达。 结果与结论：正常对照组、单纯骨折组的胰岛素样生长因子Ⅰ血清质量浓度无明显变化,脑损伤-骨折组和脊髓损伤-骨折组骨痂体积、X射线评分高于单纯骨折组(P < 0.05);伤后3 d, 1,2周时,脑损伤-骨折组和脊髓损伤-骨折组胰岛素样生长因子Ⅰ的血清质量浓度较其他两组明显增加(P < 0.01);伤后1周,脑损伤-骨折组和脊髓损伤-骨折组骨折端平均阳性细胞数高于单纯骨折组(P < 0.01)。提示中枢神经损伤可以影响血清中胰岛素样生长因子Ⅰ的质量浓度和骨痂局部的表达,从而能促进骨折愈合。     

糖皮质激素对大鼠骨折愈合方式的影响

目的:探讨糖皮质激素对大鼠骨干骨折愈合方式的影响。方法:取3月龄雌性SD大鼠60只分为实验组和对照组,实验组肌肉注射醋酸强的松5mg·kg-1.d-1,对照组注射等容积的生理盐水。3周后制成胫骨干骨折模型,骨折后不同阶段处死,分别进行组织学、骨密度、Western印迹检测骨痂中Ⅱ型胶原蛋白的表达以及生物力学测定。结果:肌肉注射醋酸强的松3周后骨密度检查证实模型制造成功。骨折后第3d2组均开始形成原始骨痂;第2周实验组软骨骨痂明显比对照组少,第4-6周实验组骨痂面积高于对照组,且软骨骨痂比例较高,骨密度减低。实验组中Ⅱ型胶原蛋白表达明显延迟。第6周生物力学测定对照组实际最大载荷为(69.77±8.46)N,较实验组(51.38±3.37)N增加35.8%。结论:大剂量糖皮质激素在大鼠骨折早期延缓软骨骨痂的产生,在骨折中后期使软骨性骨痂至骨性骨痂演变过程减缓。Ⅱ型胶原蛋白的表达延迟可能是其对骨折愈合产生不利影响的原因之一。     

局部应用神经生长因子对周围神经损伤后骨折早期愈合的影响

背景：骨折愈合机制复杂,受到多种因素的影响,骨折延迟愈合、不愈合时有发生,如何促进骨折愈合成为亟待解决的问题。 目的：观察周围神经损伤后局部应用神经生长因子对骨折早期愈合的影响。 方法：36只健康雄性Wistar大白鼠建立胫骨骨折模型,将其随机分为4组,每组18个肢体。①骨折+盐水组为胫骨骨折予以双侧腓肠肌生理盐水注射。②骨折伴神经损伤+盐水组胫骨骨折伴神经损伤予以生理盐水注射。③骨折+神经生长因子组为胫骨骨折予以局部注射神经生长因子。④骨折伴神经损伤+神经生长因子组为神经损伤、胫骨骨折予以局部注射神经生长因子。对各组骨痂计量学结果等情况进行观察对比。 结果与结论：①骨痂量：干预4周时与骨折+盐水组、骨折+神经生长因子组、骨折伴神经损伤+神经生长因子组比较,骨折伴神经损伤+盐水组骨痂量最多,其他3组比较差异无显著性意义(P > 0.05)。②骨计量指标：干预2周时,骨折伴神经损伤+盐水组骨吸收表面积明显大于骨折伴神经损伤+神经生长因子组(P < 0.05),骨折+盐水组破骨细胞指数明显大于骨折+神经生长因子组(P < 0.05);干预4周时,矿化骨小梁宽度,骨折+盐水组明显小于骨折+神经生长因子组(P < 0.05),骨折伴神经损伤+盐水组明显小于骨折伴神经损伤+神经生长因子组(P < 0.05)。结果提示周围神经损伤后的骨折局部应用神经生长因子均可增强成骨能力,且可有效抑制破骨细胞活动,促进骨折早期愈合。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

糖尿病大鼠皮肤伤口愈合过程中结缔组织生长因子的表达

背景：结缔组织生长因子表达在糖尿病伤口愈合过程中的变化及意义少见报道。 目的：观察链脲佐菌素诱导的糖尿病模型大鼠复合创伤修复过程中结缔组织生长因子表达的变化及意义。 方法：将Wistar大鼠随机分成正常对照组和模型组,3周后将各组动物复合背部1.3 cm2全厚皮切除形成伤口。 结果与结论：链脲佐菌素诱发的糖尿病模型大鼠伤口愈合明显延迟,创伤后第4,8,12 和16天创面愈合率明显低于正常对照组(P  < 0.01)。术后第8天,糖尿病组大鼠肉芽组织成熟度和新生血管形成指标得分均低于正常对照组(P < 0.01)。正常对照组的结缔组织生长因子蛋白表达呈时间递增趋势,而糖尿病组的结缔组织生长因子表达在整个创面愈合过程的后期(第12天后)均明显低于正常对照组(P < 0.01)。结果提示,糖尿病大鼠皮肤伤口愈合后期创面组织结缔组织生长因子表达相对正常对照组减少可能是导致创面愈合迟缓的重要原因之一。     

Viral interactions with the host and microbiota in the intestine

This review explores the recent advances that have been made in our understanding of host viral interactions in the intestine. Technical advances have allowed the initial definition of intestinal viromes in a number of species including humans. Important advances in our knowledge of the host response to viral infection have shown that interferon lambda has a role that is unique from type I interferons in the intestine. Lastly, our understanding of virally induced phenotypes has expanded through new studies that show bacteria can play an important role in the outcome of viral infection in the intestine.     

HLA genes in Macedonians and the sub-Saharan origin of the Greeks

HLA alleles have been determined in individuals from the Republic of Macedonia by DNA typing and sequencing. HLA-A, -B, -DR, -DQ allele frequencies and extended haplotypes have been for the first time determined and the results compared to those of other Mediterraneans, particularly with their neighbouring Greeks. Genetic distances, neighbor-joining dendrograms and correspondence analysis have been performed. The following conclusions have been reached: 1) Macedonians belong to the "older" Mediterranean substratum, like Iberians (including Basques), North Africans, Italians, French, Cretans, Jews, Lebanese, Turks (Anatolians), Armenians and Iranians, 2) Macedonians are not related with geographically close Greeks, who do not belong to the "older" Mediterranenan substratum, 3) Greeks are found to have a substantial relatedness to sub-Saharan (Ethiopian) people, which separate them from other Mediterranean groups. Both Greeks and Ethiopians share quasi-specific DRB1 alleles, such as *0305, *0307, *0411, *0413, *0416, *0417, *0420, *1110, *1112, *1304 and *1310. Genetic distances are closer between Greeks and Ethiopian/sub-Saharan groups than to any other Mediterranean group and finally Greeks cluster with Ethiopians/sub-Saharans in both neighbour joining dendrograms and correspondence analyses. The time period when these relationships might have occurred was ancient but uncertain and might be related to the displacement of Egyptian-Ethiopian people living in pharaonic Egypt.     

Responses in the inferior olive to stimulation of the cerebellar and cerebral cortices in the cat

1. Extracellular field potentials and single unit responses have been recorded from the inferior olive of the cat following stimulation of the surface of the contralateral paramedian lobule of the cerebellum, and of the ipsilateral cerebral cortex. 2. Cerebellar stimulation results in antidromic invasion of inferior olivary neurones via the climbing fibres. These responses are followed by synaptic discharges which may be generated through climbing fibre recurrent collaterals. 3. Precise histological controls have shown that these responses to stimulation of the paramedian lobule are located in the ventral lamella of the principal olive. 4. Unifocal stimulation of the sensori-motor cortex with surface-anodal pulses evokes synaptically generated discharges of neurones in the central lamella, with a latency of 8-9 msec. The area of cortex yielding responses has been mapped at chosen stimulus intensities and the limitations of the maps have been discussed. 5. It has been shown that the initial excitatory responses obtained from either cortex are followed by an inhibition which lasts about 100 msec, and gives way to a period of recovery or facilitation. This, in turn, is succeeded by a further period of inhibition. Possible neural substrates for these changes have been discussed.     

Splitting and lumping in the nosology of XLMR.

Although it is assumed that genes that influence cognitive function are ubiquitous in the human genome, to date, more such genes have been found on the X chromosome than on any other comparable segment of the autosomes. This is in large measure because of the power of hemizygosity in exposing mutations of X-linked genes in males. Clinical manifestations, mapping of gene loci by linkage analysis or chromosome rearrangements, and gene identification by positional cloning or mutational analysis of candidate genes have permitted extensive lumping and splitting within the large and heterogeneous category of X-linked mental retardation (XLMR). Approximately 130 XLMR syndromes have been identified, 25 gene loci have been mapped and cloned, and 55 other loci have been mapped but not cloned. Well-recognized syndromes (e.g., Fragile X and Coffin-Lowry syndromes) and syndromes represented by only a single family (e.g., Arena and monoamine oxidase-A syndromes) are among these more or less well-defined entities. In addition, more than 75 families with nonsyndromal XLMR have been regionally mapped and 7 causative genes have been identified.     

Tissue and cell studies of the growth plate in the chondrodysplasias

As the morphologic expression of the chondrocytic differentiation pathway responsible for bone development and growth, the growth plate has been investigated extensively in the chondrodysplasias. Unique morphologic abnormalities identified in many disorders have provided insight into pathogenetic mechanisms and have been useful diagnostically and nosologically. Biochemical studies have detected evidence of type II collagen defects in patients having disorders in the achondrogenesis type II-spondyloepiphyseal dysplasias (SED) congenita family of chondrodysplasias. Most promising may be the cell culture systems now being developed for human chondrocytes. Preliminary results suggest that they will allow the cellular and molecular biology of the dysplastic growth plate to be directly analyzed.     

Air- breathing in fish: Air- breathing organs and control of respiration: Nerves and neurotransmitters in the air-breathing organs and the skin

In fishes, exploitation of aerial gas exchange has evolved independently many times, involving a variety of air-breathing organs. Indeed, air-breathing occurs in at least 49 known families of fish (Graham, 1997). Many amphibious vertebrates, at some stage of their development are actually trimodal breathers that use various combinations of respiratory surfaces to breath both water (skin and/or gill) and air (skin and/or lung). The present review examines the evolutionary implications of air-breathing organs in fishes and the morphology of the peripheral receptors and the neurotransmitter content of the cells involved in the control of air-breathing. Control of breathing, whether gill ventilation or air-breathing, is influenced by feedback from peripheral and/or central nervous system receptors that respond to changes in PO2, PCO2 and/or pH. Although the specific chemoreceptors mediating the respiratory reflexes have not been conclusively identified, studies in water-breathing teleosts have implicated the neuroepithelial cells (NECs) existing in gill tissues as the O2 sensitive chemoreceptors that initiate the cardiorespiratory reflexes in aquatic vertebrates. Some of the air-breathing fishes, such as Protopterus, Polypterus and Amia have been shown to have NECs in the gills and/or lungs, although the role of these receptors and their innervation in the control of breathing is not known. NECs have been also reported in the specialized respiratory epithelia of accessory respiratory organs (ARO’s) of some catfish species and in the gill and skin of the mudskipper Periophthalmodon schlosseri. Unlike teleosts matching an O2-oriented ventilation to ambient O2 levels, lungfishes have central and peripheral H+/CO2 receptors that control the acid-base status of the blood.     

Dopamine and synaptic plasticity in the neostriatum

After the unilateral destruction of the dopamine input to the neostriatum there are enduring changes in rat behaviour. These have been ascribed to the loss of dopamine and the animals are often referred to as ‘hemiparkinsonian’. In the denervated neostriatum, we have shown that not only are the tyrosine hydroxylase positive boutons missing, but also the medium sized densely spiny output cells have fewer spines. Spines usually have asymmetric synapses on their heads. In a recent stereological study we were able to show that there is a loss of approximately 20% of asymmetric synapses in the lesioned neostriatum by 1 mo after the lesion. Current experiments are trying to establish the specificity of this loss. So far we have evidence suggesting that there is no obvious preferential loss of synapses from either D1 or D2 receptor immunostained dendrites in the neostriatum with damaged dopamine innervation. These experiments suggest that dopamine is somehow necessary for the maintenance of corticostriatal synapses in the neostriatum. In a different series of experiments slices of cortex and neostriatum were maintained in vitro in such a way as to preserve at least some of the corticostriatal connections. In this preparation we have been able to show that cortical stimulation results in robust excitatory postsynaptic potentials (EPSPs) recorded from inside striatal neurons. Using stimulation protocols derived from the experiments on hippocampal synaptic plasticity we have shown that the usual consequence of trains of high frequency stimulation of the cortex is the depression of the size of EPSPs in the striatal cell. In agreement with similar experiments by others, the effect seems to be influenced by NMDA receptors since the unblocking of these receptors with low Mg⁺⁺ concentrations in the perfusate uncovers a potentiation of the EPSPs after trains of stimulation. Dopamine applied in the perfusion fluid round the slices has no effect but pulsatile application of dopamine, close to the striatal cell being recorded from, and in temporal association with the cortical trains, leads to a similar LTP like effect. The reduction of K⁺ channel conductance in the bath with TEA also has the effect of making cortical trains induce potentiation of corticostriatal transmission. TEA applied only to the cell being recorded from has no similar effect; the cortical stimulation again depresses the EPSP amplitude, so the site of action of TEA may well be presynaptic to the striatal cell. The morphological and physiological experiments may not necessarily be related but it is tempting to suggest that dopamine protects some corticostriatal synapses by potentiating them but that in the absence of dopamine others simply disconnect and are no longer detectable on electron microscopy.     

Long-term potentiation and depression in the cerebral neocortex

Long-term potentiation of synaptic efficacy following tetanic synaptic inputs was described originally in the hippocampus, and it has been studied extensively based on the hypothesis that it represents a synaptic model of learning and memory in the brain. In the cerebral neocortex, studies on LTP have burgeoned later, and have progressed less rapidly than those in the hippocampus. Recently, however, experimental data describing the phenomenology and the mechanisms underlying LTP have accumulated in the neocortex, particularly in the visual, somatosensory, and motor cortices. In the developing visual cortex, LTP has been induced by afferent tetanic stimulation at relatively low frequencies, for long duration. Thus, particular attention has been given to parameters of the tetanus optimal for the induction of cortical LTP, and the differences between these and those effective in inducing hippocampal LTP have been reviewed. In the motor cortex, the associative LTP following combined activation of separate sites as well as homosynaptic LTP following activation of single pathways have been reported and these types of synaptic plasticity have been suggested as being a basis for a certain type of motor learning. Long-lasting depression (LTD) of synaptic efficacy also has been reported in the developing visual cortex and suggested as a neural basis for experience-dependent modifications of visual cortical neurons. LTD has been found in other areas of the neocortex as well, although the probability of its induction is relatively low and its functional significance is not yet clear. Among the possible mechanisms for the induction of LTP and LTD, those including the involvement of NMDA receptors, protein kinase C, Ca2+/calmodulin-dependent kinase II, and membrane-associated cytoskeletal proteins have been reviewed, although the results obtained so far are only fragmentary and are premature for definitive conclusions to be drawn.