缺氧缺血性脑损伤新生大鼠海马区脑红蛋白、凋亡相关蛋白Bcl-2、Bax的表达及其相关性

目的:探讨新生大鼠缺氧缺血性脑损伤(HIBD)后海马CA1区脑红蛋白(Ngb)及凋亡相关蛋白Bcl-2、Bax的变化规律及其相关性。方法:选用60只新生7日龄Wistar大鼠,随机分为三组:sham组(n=6),正常对照组(n=6)和HIBD组(n=48)。HIBD组新生大鼠建立HIBD模型,分别于HIBD后3h、6h、12h、24h、48h、72h、7d、14d取材,应用免疫组织化学染色方法检测各组海马CA1区Ngb及Bcl-2、Bax的表达变化情况。结果:(1)与sham组相比,HIBD组Ngb阳性细胞数于缺氧缺血后3h开始下降,但差异无统计学意义;6h、12h、24h呈逐渐下降趋势,阳性细胞数量已明显低于sham组;到48h时达最低水平;14d时Ngb阳性细胞数量基本恢复至sham组水平。(2)与sham组相比,HIBD组于缺氧缺血3hBcl-2阳性表达细胞开始显著增多,于12h达到高峰,24h时开始逐渐下降,14d时略高于sham组表达,但差异无统计学意义。(3)与sham组相比,HIBD组Bax蛋白免疫反应阳性细胞数目于缺氧缺血后3h时开始增加,12h时明显增多,于48h达高峰,此后逐渐下降,7d时阳性细胞数基本恢复至sham组水平,14d时未见Bax蛋白的阳性表达。(4)新生大鼠海马CA1区内,Ngb阳性细胞数与Bcl-2阳性细胞数无相关;与凋亡相关蛋白Bax阳性细胞数呈负相关(r=-0.697,P0.01)。结论:Bcl-2与Bax基因参与了HIBD后神经细胞凋亡的发生;Ngb可能通过抑制促凋亡蛋白Bax的表达,从而减少神经细胞的凋亡,发挥其神经保护作用。     

新生鼠脑缺氧缺血时天冬氨酸半胱氨酸蛋白酶-3表达的研究

目的：探讨新生大鼠缺氧缺血脑损伤（HIBD）时皮质及海马中天冬氨酸半胱氨酸蛋白酶-3（caspase-3）表达的变化。方法： 分假手术组和模型（HI）组。用新生7 d的大鼠建立新生儿HIBD的模型，于缺氧后不同时点取脑，分别行病理学检查、免疫组化和半定量逆转录-聚合酶反应（RT-PCR），观察双侧皮质及海马caspase-3 蛋白及mRNA表达的程度。结果： HI组皮质及海马caspase-3 mRNA 于HI后0 h出现瞬时高表达，然后下降，6 h可检测到mRNA和蛋白同时升高，表达峰值于HI后24-48 h出现，然后下降。结论： Caspase-3参与未成熟脑HIBD后皮质及海马区神经细胞凋亡的进程。在其表达峰值出现以前，即HI后24-48 h之前，抑制caspase-3的表达，应是治疗脑损伤的适宜时机。     

CEPO调控新生大鼠缺氧缺血性脑损伤Bcl-2、Bax基因表达的研究

目的 观察新生大鼠缺氧缺血性脑损伤（HIBD）脑组织Bcl-2、Bax基因表达变化及氨基甲酰化促红细胞生成素（CEPO）干预对其表达的影响,探讨CEPO发挥脑保护作用的可能机制.方法 将新生7日龄SD大鼠建立HIBD模型,利用RT-PCR检测缺氧缺血和CEPO干预后2h、12h、24 h、48 h、72 h凋亡基因Bcl-2、Bax的mRNA表达的改变.结果 与假手术组相比,缺氧缺组在2h、12h、24 h、48 h、72 h脑组织中Bcl-2、Bax的表达均增加（P＜0.05）,与缺氧缺血组相比,CEPO干预组在不同时间点Bcl-2表达增加（P＜0.05）,Bax表达下降（P＜0.05）.结论 在新生大鼠HIBD中Bcl-2、Bax mRNA的表达发生改变,调控二者的表达水平可能是CEPO发挥脑保护的作用机制之一.     

脑缺氧缺血后新生大鼠海马CA1区NMDAR的表达

目的 :研究新生大鼠缺氧缺血性脑损伤 (HIBD)后 ,海马CA1区N甲基D天门冬氨酸受体 (NMDAR)及NMDARmRNA表达的变化。方法 :建立HIBD模型 ,用免疫组化及原位杂交方法 ,检测正常对照 (NORM)组和缺氧缺血 (HI)后不同时间点 ,NMDA受体I型亚单位 (NR1)表达的阳性细胞及NR1mRNA表达的阳性细胞。结果 :HI后 2h时NR1、NR1mR NA的表达稍下降 ,2 4h开始上升 ,72h达高峰 ,与正常对照组相比较有显著意义 (P <0 .0 5 )。结论 :正常新生大鼠海马CA1区有NR1及NR1mRNA的表达 ,HI后NR1及NR1mRNA的表达上调     

Bcl-2、Bax蛋白在NRs抗体预处理后缺氧缺糖海马脑片CA_1区的表达变化

运用海马脑片培养技术、海马脑片缺氧缺糖方法、免疫组织化学染色和图像分析处理技术观察用 NMDA受体亚单位抗体预处理后再缺氧缺糖的海马脑片 CA1 区 Bcl-2和 Bax蛋白的表达变化 ,以探究其亚单位与海马脑片缺氧缺糖性损伤的关系。结果显示 ,各实验组海马脑片 CA1 区均有不同程度 Bcl-2、Bax蛋白表达和细胞缺失形成的空洞。 Bcl-2蛋白在 NR1+ OGD组、NR2 A+ OGD组和 NR2 A + NR2 B+ OGD组 CA1 区的表达均明显弱于 OGD组 (3组均 P<0 .0 5 ) ;其在 NR2 B+ OGD组和HOTC组的表达则强于 OGD组 (两者 P<0 .0 5 )。 Bax蛋白在 NR1+ OGD组、NR2 A+ OGD组和 NR2 A+ NR2 B+ OGD组的表达均强于 OGD组 (NR2 A+ OGD组 P<0 .0 5 ) ;在 NR2 B+ OGD组和 HOTC组其表达则明显弱于 OGD组 (后者 P<0 .0 5 )。结论 :单纯缺氧缺糖可引起海马脑片 CA1 区锥体细胞的迟发性损伤 ,同时引起 Bcl-2蛋白和 Bax蛋白的表达变化 ;预加 NMDA受体亚单位 NR1、NR2 A抗体和 NR2 A+ NR2 B抗体可以加重缺氧缺糖性海马脑片 CA1 区细胞损伤程度 ;预加 NR2 B抗体则可减轻其损伤程度。提示 NMDA受体亚单位成分的变化可以调节 Bcl-2和 Bax蛋白在缺氧缺糖性海马脑片 CA1 区的表达 ,从而调节CA1 区神经元的损伤程度     

低分子肝素抗新生大鼠大脑皮层神经细胞缺氧性凋亡

目的：探讨低分子肝素对体外培养的新生大鼠大脑皮层神经细胞缺氧性凋亡的作用机制。方法： 应用“neurobasal 加 B27 supplement”体外培养大鼠大脑皮层神经细胞，并在缺氧条件下使用Hoechst 33342荧光染色法、免疫细胞化学染色法观察低分子肝素对原代神经细胞的抗凋亡作用。结果： 在250-500 U/L的浓度范围內，低分子肝素能降低缺氧诱导的神经细胞凋亡率（P<0.05），并且较BDNF（50 μg/L）抗凋亡阳性对照组的凋亡率更低（P<0.05）。低分子肝素（500 U/L）增加缺氧的神经细胞Bcl-2蛋白的表达（P<0.05），减少Bax蛋白的表达（P<0.01），提高Bcl-2/Bax比值（P<0.01）。低分子肝素500 U/L组的Bcl-2/Bax比值比正常对照组、BDNF抗凋亡阳性对照组和凋亡阳性组都高（P<0.05）。结论： 低分子肝素通过上调缺氧神经细胞Bcl-2表达和下调Bax表达，提高Bcl-2/Bax比值减少缺氧的神经细胞凋亡。     

穴位埋线对血管性痴呆大鼠海马CA1区神经细胞凋亡的影响

目的 观察穴位埋线疗法对血管性痴呆（VD）大鼠海马CA1区神经细胞凋亡和Bcl-2 mRNA及Bax mRNA表达的影响,探讨穴位埋线对VD大鼠脑缺血性损伤的神经保护机制。 方法 采用改良Pulsinelli’s 4血管阻断法建立VD大鼠模型,随机数表法分为VD模型组、穴位埋线组、尼莫地平组,并设置假手术组作为对照。两个治疗组分别施行穴位埋线和尼莫地平治疗。Morris 水迷宫检测各组大鼠学习记忆能力后,取含海马的脑组织,TUNEL法检测海马CA1区神经细胞凋亡,原位杂交法检测其Bcl-2 mRNA及Bax mRNA表达,观察并比较各组大鼠海马神经细胞凋亡、蛋白表达的变化。 结果 VD模型组大鼠海马CA1区可见大量凋亡细胞、Bcl-2 mRNA 表达降低、Bax mRNA 的表达增高,与假手术组比较差异均有统计学意义（P＜0.01）。VD模型组表现出明显的学习记忆障碍,与假手术组相比差异有统计学意义（P＜0.01）;与VD模型组比较,穴位埋线组大鼠学习记忆能力显著提高（P＜0.01）,CA1区凋亡细胞明显减少（P＜0.01）,可见一定数量的Bcl-2 mRNA阳性细胞表达,而Bax mRNA阳性细胞表达较少。 结论 穴位埋线可通过上调VD大鼠海马CA1区Bcl-2 mRNA的表达、下调Bax mRNA 的表达,抑制海马神经细胞凋亡,改善VD大鼠学习记忆能力。     

神经干细胞移植对HIBD新生大鼠学习记忆的影响

目的：探讨脑内移植胚鼠神经干细胞 (NSCs)对新生大鼠缺氧缺血性脑损伤(HIBD)后学习记忆的影响。 方法： 分离孕龄14 d的Sprague-Dawley（SD）大鼠胚胎前脑皮质，采用无血清悬浮培养的方法获得细胞克隆；7 d龄新生大鼠随机分为假手术组（n=10）、HIBD组（n=11）和移植组（n=13），后两组结扎左侧颈总动脉联合8%氧吸入制作HIBD模型，损伤后3 d利用立体定位仪分别在左侧海马区植入培养基作为对照或BrdU 标记的NSCs，观察植入4 周后大鼠学习记忆功能的恢复情况。计数海马CA1区正常神经元，间接免疫荧光法观察移植细胞在脑内的存活、迁移情况。 结果： 在放射形迷宫测试中，移植组较对照组表现出明显的改善，觅水时间缩短(61.40 s±24.83 s vs 89.32 s±31.52 s)，错误次数（2.65±0.57 vs 3.78±0.41）及重复次数明显减少(0.32±0.43 vs 0.81±0.47)(P<0.05)。BrdU间接免疫荧光显示移植后4周，在脑内可见存活的NSCs在海马内广泛分布；尼氏染色显示移植可明显减少海马CA1区的细胞丢失。 结论： 脑内移植胚鼠NSCs对HIBD新生大鼠的学习记忆恢复有良好的促进作用。     

黄芪注射液对缺氧缺糖/复氧复糖大鼠海马神经元Bcl-2和Bax表达的影响

目的: 观察黄芪注射液对缺氧缺糖/复氧复糖大鼠海马神经元凋亡相关蛋白Bcl-2、Bax及其mRNA表达的影响。方法: 取原代培养8 d的大鼠海马神经元,随机分为4组:正常对照组、模型组(缺氧缺糖/复氧复糖组)、溶剂对照组(缺氧缺糖/复氧复糖+黄芪注射液溶剂处理组)和黄芪注射液处理组(缺氧缺糖/复氧复糖+黄芪注射液处理组)。除正常对照组外,各组均进行缺糖缺氧0.5 h,再分别于复氧复糖后0 h、0.5 h、2 h、6 h、24 h、72 h和120 h采用Western blotting法检测海马神经元Bcl-2和Bax蛋白的表达,RT-PCR法检测海马神经元bcl-2和bax mRNA的表达。结果: Western blotting结果显示:与正常对照组比,模型组Bcl-2和Bax蛋白表达明显升高,而Bcl-2/Bax比值下调(P<0.05);与模型组比,黄芪注射液处理组Bcl-2蛋白表达升高,Bax蛋白表达明显降低,Bcl-2/Bax比值升高( P<0.05),而溶剂对照组Bcl-2、Bax蛋白表达及Bcl-2/Bax比值则无显著变化(P>0.05)。bcl-2 mRNA、bax mRNA表达趋势同蛋白。结论: 黄芪注射液可提高缺氧缺糖/复氧复糖大鼠海马神经元Bcl-2表达及Bcl-2/Bax比值,抑制Bax表达,从而抑制缺氧缺糖/复氧复糖引起的海马神经元凋亡。     

C57black/6小鼠全脑缺血模型的海马区Bcl-2和Bax的表达

使用 C5 7black/6小鼠制造的全脑缺血模型 ,观察全脑缺血后海马 Bcl-2和 Bax的表达 ,为这种新的模型在脑缺血研究中的应用提供实验依据。双侧颈总动脉夹闭 15 min诱发全脑缺血模型 ,2 4h后取脑组织进行 Bcl-2和 Bax免疫组织化学染色。缺血组海马 Bax阳性反应神经元数目增多 ,主要分布在 CA1 区 ,胞浆深染 ,假手术组 Bax阳性细胞数目少 ,染色浅。缺血组 CA3区和齿状回 Bcl-2阳性反应神经元数目增多 ,胞浆染色深 ,假手术组 Bcl-2阳性细胞数目少 ,染色浅。C5 7black/6小鼠全脑缺血模型的海马内 Bcl-2和 Bax表达发生改变 ,Bax表达增加在 CA1 区 ,Bcl-2表达增加在 CA3区和齿状回 ,提示二者在该模型的脑缺血后神经细胞死亡过程中发挥作用     

Relation of plasma protein oxidation parameters and paraoxonase activity in the ageing population

The incidence of atherosclerosis increases with age. Oxidative changes in proteins and lipids are considered to be among the molecular mechanisms leading to endothelial dysfunction. Paraoxonase (PON1) is exclusively associated with high-density lipoprotein (HDL) and protects both HDL and low-density lipoprotein (LDL) from oxidation. PON1 has two cysteine residues for its antioxidant function. We investigated the relation between PON1 activity and protein oxidation parameters such as protein hydroperoxides (P-OOH), protein carbonyl (PCO), total thiol (T-SH) and advanced oxidation protein products (AOPP). Our study also covered other oxidative stress parameters such as oxidised LDL (oxLDL) and superoxide dismutase activity in the plasma of young, middle-aged and elderly individuals. PON1 activity of elderly and middle-aged individuals was decreased significantly compared with that in the young group. oxLDL levels of elderly individuals were increased significantly compared with those of both the young and middle-aged individuals. P-OOH, PCO and AOPP levels of the elderly and middle aged individuals were higher compared with those of the young. On the other hand, T-SH levels of the elderly and middle-aged individuals were lower compared with those of the young. Side by side with the decrease in the T-SH levels in the middle-aged and elderly groups as compared to the young, the increase we have observed in other protein oxidation parameters in the groups leading to decreasing PON1 activity might, we think, create a predisposition to atherosclerosis.     

Modified immunogold labelling applied to the study of protein droplets in glomerular disease

Summary Glomerular protein droplets have been observed in human glomerular epithelial cells, peripolar cells and mesangial cells, particularly in the preeclamptic lesion. Although morphologically similar, their functional role is uncertain. Whilst previous electron microscopic studies have shown these droplets to be generally uniform in electron density, our immunoelectron microscopy study of 10 biopsies, one showing lesions of preeclampsia, and the remaining 9 showing different forms of glomerular disease, generally displayed two distinct patterns of electron density and immunolabelling, when using a less severe fixation regime. An electron dense inner core was strongly positive to anti-fibrinogen, whilst a less dense peripheral zone was positive to anti-IgM. All other immunoglobulins, C₃c, and albumin showed a less specific immunolabelling pattern. Protein droplets were also observed in proximal tubules in 7 out of 10 biopsies. In droplets found in most tubular cells immunolabelling was not partitioned, the most prominent findings being diffuse labelling for fibrinogen and albumin.In most instances where glomerular droplets were found adjacent to intraglomerular deposits, the marker identified within the deposit could also be seen in either the core area or the peripheral zone of the droplets. These findings raise the possibility that these droplets may be involved in protein absorption from the deposits through a damaged glomerular basement membrane.     

The effect of hypokinesia and hypodynamia on protein turnover and the growth of four skeletal muscles of the rat

An animal suspension model has been used to simulate the weightlessness experienced during space travel. This procedure results in a reduction in the normal shortening (i.e. hypokinesia) and force generation functions of hind limb muscles (i.e. hypodynamia). The ensuing muscle atrophy was studied over 12 days in different muscle types. Slow muscles (e.g. the soleus) underwent a more pronounced atrophy than intermediate (i.e. gastrocnemius) and fast phasic muscles (e.g. extensor digitorum longus). In all muscle types inactivity resulted in a smaller accumulation of DNA and losses of RNA and protein after 5 days. The latter arose from a decrease in the rate of protein synthesis (measured in vivo) and an increase in protein breakdown. Increased specific activities of cathepsins B and D also supported the view that there is an increased proteolysis after hypokinesia and hypodynamia.When the inactive soleus was simultaneously held in a lengthened (stretched) state the atrophy was prevented through a large increase in the fractional rate of protein synthesis. Protein degradation remained elevated with stretch, thereby slowing the growth of these muscles relative to those in pair-fed, ambulatory controls. The much smaller atrophy of the tibialis anterior and extensor digitorum longus muscles in suspended only limbs represented an underestimate of the true atrophic effects of hypokinesia and hypodynamia. In this model gravity pulls the suspended foot into a plantar flexed position, thereby permanently stretching and protecting such flexor muscles. When this influence of stretch was removed a greater atrophy ensued, mainly due to the loss of the stretch-induced stimulation of protein synthesis. Despite this, the inactive fast-twitch muscles still exhibited less atrophy than the gastrocnemius and soleus muscles.     

Polymorphic forms of the protein L-isoaspartate (D-aspartate) O-methyltrans-ferase involved in the repair of age-damaged proteins

The protein L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) can initiate the repair of age-damaged aspartyl and asparaginyl residues of intracellular proteins. The human gene PCMT1 encoding this enzyme has at least four polymorphic sites, one of which results in two major isoforms with either an Ile residue or a Val residue at amino acid position 119. The frequencies of the alleles encoding the Ile₁₁₉ and Val₁₁₉ variants are similar in Caucasian populations, but a predominance of the Ile₁₁₉ allele exists in Asian and African populations. Analyses of the enzymatic activities of the Ile₁₁₉ and Val₁₁₉ variants in red blood cell lysates show that the higher specific activity and thermostability of the Ile₁₁₉ isoform is balanced by the potentially compensating higher substrate affinity of the Val₁₁₉ isoform. In a preliminary attempt to find an association between genotype frequency at the PCMT1 locus and healthy aging, we compared the distribution of genotypes in a healthy older population of Ashkenazi Jewish individuals with that in a younger ethnically matched control group. We found that 65% of the healthy older population had the heterozygous genotype, greater than the 50% expected by Hardy-Weinberg equilibrium, suggesting a possible selection for having both alleles of the repair methyltransferase in successful aging. Three additional polymorphisms in non-coding regions of the methyltransferase gene were found to be biallelic and demonstrated nonrandom association in a specific haplotype with the codon 119 polymorphism. Finally, we also detected a heterozygous mutation in the splicing branch site of intron 2 that did not appear to affect activity. This study will help define the normal physiological range of activity for this repair methyltransferase and give us a better understanding of its role in the processes of aging and disease. Received: March 11, 1999 / Accepted: April 23, 1999     

Over-expression,purification and determination of the proteolytic processing site of the yeast mitochondrial CBS1 protein

Summary Yeast transformats harboring the CBS1 gene under the control of the strong ADC1 promoter on a high copy number plasmid express the mitochondrial CBS1 protein at artificially high levels. Over-expressed protein is imported into mitochondria and correctly processed to vield the mature mitochondrial 23.5 kDa form, but differs in its solubility properties from CBS1 in wild-type mitochondria. It forms insoluble protein aggregates, which are refractory to solubilization with 1% Taurodeoxycholate. We exploited this observation to separate CBS1 from the bulk of mitochondrial proteins and to isolate CBS1 after SDS gel electrophoresis. Determination of the amino-terminal amino acids of the purified protein reveals that the mature CBS1 protein starts with Ile³⁰, at the characteristic distance of +2 amino acids from an arginine residue (Arg²⁸). The cleavage site shows a remarkable homology to that of subunit 9 of the F₀F₁ ATPase from Neurospora crassa.     

SPlitSSI-SVM: An algorithm to reduce the misleading and increase the strength of domain signal

Protein domains contain information about the prediction of protein structure, function, evolution and design since the protein sequence may contain several domains with different or the same copies of the protein domain. In this study, we proposed an algorithm named SplitSSI-SVM that works with the following steps. First, the training and testing datasets are generated to test the SplitSSI-SVM. Second, the protein sequence is split into subsequence based on order and disorder regions. The protein sequence that is more than 600 residues is split into subsequences to investigate the effectiveness of the protein domain prediction based on subsequence. Third, multiple sequence alignment is performed to predict the secondary structure using bidirectional recurrent neural networks (BRNN) where BRNN considers the interaction between amino acids. The information of about protein secondary structure is used to increase the protein domain boundaries signal. Lastly, support vector machines (SVM) are used to classify the protein domain into single-domain, two-domain and multiple-domain. The SplitSSI-SVM is developed to reduce misleading signal, lower protein domain signal caused by primary structure of protein sequence and to provide accurate classification of the protein domain. The performance of SplitSSI-SVM is evaluated using sensitivity and specificity on single-domain, two-domain and multiple-domain. The evaluation shows that the SplitSSI-SVM achieved better results compared with other protein domain predictors such as DOMpro, GlobPlot, Dompred-DPS, Mateo, Biozon, Armadillo, KemaDom, SBASE, HMMPfam and HMMSMART especially in two-domain and multiple-domain.     

运用蛋白质芯片技术鉴定干扰素的亚型

目的：采用自制的6株干扰素单克隆抗体，在本实验室建立的金基底蛋白质芯片平台上对IFN-α1b、IFN-α2a、IFN-α2b、IFN-β及IFN-γ进行鉴定。方法：金基底蛋白质芯片用已知亚型的IFN半成品包被，封闭后与自制的6株干扰素单抗反应，再与Cy3-羊抗鼠IgG反应，反应后GenePix4100A芯片扫描仪扫描读数，将结果与ELISA法、Western blot法比较。同样方法检测IFN成品。结果：金基底蛋白质芯片检测技术结果表明，该平台鉴定干扰素的亚型具有特异性，与ELISA法、Western blot法能得出一致的结论。结论：运用本实验室建立的蛋白质芯片平台可以对干扰素的亚型进行鉴定，具有高通量，操作简单，样品用量少，重复性强等优点。     

吗啡长时程作用对小鼠脑组织蛋白激酶A及C活性的影响

本文通过复制小鼠吗啡耐受依赖模型，观察了吗啡长时程作用对小鼠脑组织ＰＫＡ及ＰＫＣ活性的影响。结果发现：（１）吗啡耐受依赖小鼠纹状体、海马、大脑皮层神经细胞胞浆ＰＫＡ活性显著升高，而小脑胞浆及以上各部位膜相ＰＫＡ活性变化不明显；（２）不同脑组织中ＰＫＣ活性变化不同，吗啡耐受依赖小鼠大脑皮层及小脑胞浆ＰＫＣ活性明显升高，在纹状体胞浆则显著下降，但纹状体膜相ＰＫＣ活性却显著增加，海马及小脑膜相ＰＫＣ活性则明显降低；（３）纳洛酮可拮抗吗啡引起的上述变化。结果提示：一些脑组织胞浆ＰＫＡ活性的升高、ＰＫＣ活性的变化以及可能存在的ＰＫＣ于胞浆和膜相之间的移位可能是吗啡耐受依赖的重要生化基础，且此变化可能由阿片受体所介导。     

类金刚石薄膜成分变化对蛋白吸附的影响

采用全方位离子注入离子束增强沉积工艺制备类金刚石薄膜 (DL C) ,再将 DL C进行有氧和低压氩气保护条件下的热处理 ,分别得到富石墨相 DL C和富金刚石相 DL C。通过 X光电子能谱分析了三种 DL C的碳相组成 ,用放射性同位素 1 2 5I标记法 ,测定了恒温条件下人血白蛋白 (HSA)、纤维蛋白原 (HFG)和免疫球蛋白 (Ig G)在 3种 DL C材料表面的吸附量。结果 ,经两种不同的热处理工艺 ,DL C中石墨相和金刚石相分别增加了一倍左右 ;随着石墨、金刚石等杂质相的增加 ,DL C对 HSA的吸附能力下降 ,对 HFG和 Ig G的吸附能力显著提高 ,同时蛋白吸附特性也由原来对 3种蛋白的非特异性吸附 ,转变为对 HFG和 Ig G的优先吸附。这一结果表明 ,石墨和金刚石等杂质相将严重影响 DL C的蛋白吸附性能 ,并进而对 DL C的血液相容性产生负面影响。文中还对石墨和金刚石相的转化生成机理进行了探讨     

Bone Morphogenetic Protein 2 Induces the Expression of Cementum Attachment Protein in Human Periodontal Ligament Clones

Cementum is continuously formed during the lifetime of a tooth. The paravascular zones in the adult periodontal ligament (PL) comprise the progenitors for the fibroblastic (Fb) lineage and mineralized tissue-forming (MTF) cell lineages--the osteoblastic (Ob) and cementoblastic (Cb) lineages. Recent studies indicate that cementum attachment protein (CAP) is related to the differentiation of the Cb lineage and is instrumental in differentiating between the three periodontal cell lineages. The purpose of this study was to assess the effect of bone morphogenetic protein 2 (BMP2) on the expression of cementum attachment protein (CAP) and on the differentiation of cloned PL progenitors. The effect of BMP2 on CAP expression and on the differentiation of cloned Fb and MTF progenitors was tested by assessing the expression of alkaline phosphatase (ALP), CAP, and bone sialoprotein (BSP) by immunochemistry and by determining the CAP-binding capacity of these clones. Untreated Fb clones were negative for all tested markers and had low CAP-binding capacity. Untreated MTF clones had a high CAP-binding capacity and were positive for the three markers. BMP2 enhanced the CAP-binding potential of both Fb and MTF clones. BMP2 induced the expression of CAP, ALP, and BSP in the Fb clones and enhanced the expression of CAP and BSP in the MTF clones. These results indicate for the first time that BMP2 can recruit progenitors to the Cb lineage and regulate the differentiation of the Cb lineage by inducing and enhancing the expression of CAP, a cell lineage-specific regulator. Furthermore, the results suggest that the MTF and Fb lineages may originate from a common early progenitor cell.