Cell mediated calcification in collagen gel cultures of fetal rat calvaria cells. Loss of gap junctions precedes calcification

Summary To analyze the mechanism of initiation of cell-mediated calcification in hard tussue and its relationship to the frequency of gap junctions, enzymatically isolated cells from fetal rat calvaria cultured in collagen gels were observed ultrastructurally over a time course. Calcification was observed at 2–3 weeks after the initiation of culture when the seeding cellularity and the concentration of β-glycerophosphate were sufficiently high. In the collagen gels, round cells (R), spindle or stellate cells (S), and fat cells (F) were characterised morphologically. The ultrastructural features of initial calcification could be classified into 4 subtypes: 1) a large mass greater than 10 μm in diameter (Type I), 2) deposition associated with dead R cells or matrix vesicles (Type II), 3) intracellular deposition (Type III), and 4) other than Types I–III (Type IV). Type II was the most frequent (44.5%) and Type III was the least (6.8%). Gap junction was observed frequently between 1) R cells, 2) S cells, 3) between R cells and S cells. The frequency of gap junctions in collagen gels decreased statistically (X²-test; p<0.001), when calcification was initiated. This cell culture system can be regarded as a useful model to analyze the initiation of cell mediated calcification in hard tissue. Gap junctions might function in cell communication and a decrease in their numbers could lead to cell death and, subsequently to calcification.     

红蓝光照射联合胶原贴敷料治疗寻常痤疮疗效观察

目的观察红蓝光照射联合胶原贴敷料治疗寻常痤疮疗效和安全性。方法126例寻常痤疮患者随机分成两组,试验组采用红蓝光照射联合胶原贴敷料治疗,对照组采用红蓝光照射治疗。结果治疗4周后试验组和对照组患者有效率分别为93．9％和73．3％,差异有统计学意义（P〈0．01）。结论红蓝光照射联合胶原贴敷料治疗寻常痤疮安全有效。     

牙本质内Ⅰ型胶原纤维形态的免疫标记初探

目的初步探讨进行免疫标记的牙本质脱矿后暴露的Ⅰ型胶原纤维。方法利用免疫组化技术和场发射扫描电镜(FEISEM)相结合,对暴露胶原纤维的形态以及结构完整性进行评价。结果通过FEISEM观察,牙本质脱矿后暴露的Ⅰ型胶原纤维,可以结合抗Ⅰ型胶原单克隆抗体以及胶体金标记的相应二抗,胶体金标记颗粒分布均匀,可与暴露的胶原纤维上的抗原表位相结合,实现免疫定位。结论免疫组化技术和FEISEM相结合,可以直观观察胶原纤维立体网络的超微结构,是一种准确的、可复制的、可行的方法 。     

内外源性结缔组织生长因子对肾小管上皮细胞胶原合成的比较研究

目的：探讨内外源性结缔组织生长因子（CTGF）对人肾小管上皮细胞（HK2）胶原合成的作用。方法：将HK2细胞分为5组：（1）对照组；（2）TGF-β₁ 5 μg/L刺激组；（3）CTGF 5 μg/L刺激组；（4）TGF-β₁ 5 μg/L刺激＋CTGF反义ODN 3 mmol/L干预组；（5）TGF-β₁ 5 μg/L刺激＋CTGF正义ODN 3 mmol/L干预组。采用 RT-PCR 和Western blotting检测胶原Iα₁（Col Iα₁）、胶原IVα₁（Col IVα₁） mRNA水平和蛋白水平表达。 结果：TGF-β₁刺激可使HK2细胞Col Iα₁、Col IVα₁ mRNA和蛋白表达显著升高，而CTGF刺激则无此作用，CTGF反义ODN可拮抗TGF-β₁刺激引起Col Iα₁、Col IVα₁ mRNA和蛋白表达升高，正义ODN无拮抗作用。 结论：内源性CTGF介导了TGF-β₁刺激引起的HK2细胞胶原合成，外源性CTGF对HK2细胞胶原合成无影响。     

循环纤维细胞和人胚肺成纤维细胞的比较研究

目的 比较人循环纤维细胞与人胚肺成纤维细胞的形态学特征和合成胶原的能力.方法 体外分离、培养人循环纤维细胞,用酶水解法和天狼星红染色法分别测定培养液中的羟脯氨酸含量和细胞层中的胶原含量,比较其在不同分化阶段与培养的人胚肺成纤维细胞合成胶原的能力,同时用Western blotting分析其分泌胶原的类型.结果 循环纤维细胞在体外分化过程中,形态学特征不断变化,从圆形幼小、多聚集成"细胞岛"的纤维细胞向梭形、透明、边缘多纤毛状突起的成纤维细胞样细胞分化,在分化过程中不断合成胶原,尤其在培养的细胞层中伴有大量胶原沉积,所分泌的胶原以I型和Ⅲ型胶原为主.结论 循环纤维细胞能够在体外分化为成纤维细胞样细胞,与人胚肺成纤维细胞具有相似的胶原合成能力.     

Optical anisotropies in corneal stroma collagen fibers from diabetic spontaneous mice

In this work, optical retardation (OR) was investigated in corneal stroma collagen fibers from nonobese diabetic (NOD) and healthy (BALB/c) mice. Linear dichroism (LD) was investigated in corneas stained with Ponceau SS and Toluidine Blue, using microspectrophotometer. NOD corneas showed higher OR values than the control. Ponceau SS-complexed collagen fibers showed positive LD that was higher for NOD corneas. After staining with Toluidine Blue, NOD and BALB/c corneas showed negative LD. The results of this study demonstrate that diabetes was capable of altering the corneal optical anisotropies, possibly altering the number of intermolecular crosslinks in collagen fibers.     

Urinary β-1-galactosyl-0-hydroxylysine (GH) as a marker of collagen turnover of bone

Summary β-1-galactosyl-0-hydroxylysine (GH) was measured in the urine of 59 women and 48 men, aged 30–79 years, by High Performance Liquid Chromatography (HPLC) of the dansylated derivative. Vertebral mineral density, measured by quantitative computed tomography (QCT), and urinary GH were inversely correlated (r=−0.74;P<0.001). High rate of bone mineral loss is associated with a high urinary GH excretion. Measurement of GH in urine provides a simple and noninvasive method for the evaluation of the extent of bone resorption in large groups of subjects and appears to be more specific than urinary hydroxyproline excretion.     

Twisted plywood architecture of collagen fibrils in human compact bone osteons

Summary Ultrathin sections of decalcified human compact bone, observed by transmission electron microscopy, reveal that collagen fibrils can be distributed in the form of a superimposed series of nested arcs. This characteristic pattern has never been interpreted in previous works on compact bone structure. We demonstrate, by goniometric observations at the ultrastructural level, that such series of nested arcs are a consequence of the “twisted plywood” architecture of collagen fibrils in the compact bone matrix. In the same specimens, an “orthogonal plywood” disposition of collagen fibrils is also observed; a transition exists between these two types of orders. We show that the “twisted plywood structure” accounts well for certain optical properties of osteons, observed in polarizing microscopy, described as “intermediate osteons.” The particular geometry of collagen fibrils, leading to nested arcs in oblique sections, is analogous to the distribution of molecules in certain liquid crystals (called cholesteric liquid crystals). The principle of a liquid crystalline self-assembly of the collagen matrix in bone is therefore discussed.