新型生物——人工复合血管研制的初步报告

本文设计一种由胶原和高分子聚合物组成的新型生物一人工复合血管。其研制过程是将包绕有聚酯网的硅胶棒埋入羊的皮下组织,再将形成的经聚酯网为支架的胶原管经醛化处理。作者通过肉眼和SEM观察提出了研制生物——人工复合血管的要点:聚酯网网孔要合适,其与硅胶棒的间隙要恰当,理化处理方法更要选择好。     

胶原转录反式调控因子研究进展

Ｉ型胶原是晚期肝纤维化的主要细胞外间质成分之一,以Ｉ型胶原为主的胶原转录激活主要与ＰＳ－１,ＮＦ－Ｉ,ＡＰ－１等核转录因子有关,新的尚未发现的核蛋白因子尚在不断认识中,该研究对于揭示肝纤维化乃至器官纤维化的发生机制具有重要意义。     

胶原膜与羟基磷灰石应用于牙周牙髓联合病变的探讨

目的：初步探索胶原膜与羟基磷灰石在治疗牙周牙髓联合病变中牙槽骨缺损的作用。方法：患牙进行根管治疗,调颌及牙周翻瓣术。其中２１例患牙的牙周骨缺损区植入胶原膜和羟基磷灰石;２０例以传统血充盈法关闭骨腔。二组患牙于治疗后１、３、６、１２、２４个月分别进行随访;结果：提示应用胶原膜和羟基磷灰石组的疗效明显优于对照组,并有统计学上差异。结论：胶原膜加羟基磷灰石治疗牙周牙髓联合病变的方法值得提倡。     

皮下埋植剂避孕5年临床观察

皮下埋植剂是一种长效、安全、可逆的避孕方法。我站１９９３年６月至１９９８年６月临床应用国产Ⅱ型埋植剂２根型１２６０例,现将结果报告如下。１材料与方法１．１材料ＬＮＧ皮下埋植剂是国产Ⅱ型左旋炔诺孕酮硅胶棒,系上海达华制药厂生产,每份２根硅胶棒组成。每根...     

浒苔(Enteromorpha prolifera)藻体发育的显微观察

通过显微镜观察以及石蜡切片法观察了浒苔属浒苔藻体的发育过程,阐述了浒苔从孢子释放到形成成熟藻体这一发育过程的显微特征。结果表明:浒苔孢子由成熟体细胞分化发育而成,每个成熟体细胞可形成10～30个孢子;孢子首先分裂为2细胞结构,2细胞具有明显的极性,基细胞发育成为假根,顶端细胞不断进行横分裂形成丝状体;丝状体顶端以下细胞通过纵分裂形成管状叶状体,顶端细胞始终保持横分裂;纵分裂分为切向分裂与径向分裂,切向分裂增加管状叶状体管周细胞数从而使管体增大,径向分裂形成管外壁突起细胞,最终发育为分枝;管状叶状体管腔内部有绒毛状的突起及糖蛋白成分的网架结构;当管状叶状体管周细胞达到30～50h,管腔内部突起消失,网架结构收缩拉紧,管壁细胞贴近形成片状叶状体;整个浒苔藻体始终保持极性发育。     

长白山风灾景观30年格局变化过程分析

以长白山自然保护区内的由1986年台风形成的风灾景观为研究对象。选取1987年、1993年、1999年、2004年、2010年和2016年遥感影像进行解译。利用Fragstats 4.2软件对景观格局指数进行定量分析,并用主成分分析法与景观综合评价指数相结合的方法对景观格局变化做出综合评价,揭示风灾后30年景观格局变化过程。结果表明：(1)草本-灌木的优势度不断下降;阔叶林和针叶林在恢复过程中先以增加大斑块为主,后期面积增加主要是以小斑块为主;岳桦林恢复过程中先以增加小斑块为主,后期以大斑块连片生长。(2)小而分散的斑块在恢复过程中转换为大而集中的斑块,景观趋于均质化。(3)草本-灌木,阔叶林,针叶林,岳桦林四种斑块类型在恢复过程中呈现一种演替关系。(4)确定了分别与景观规模、形状和景观聚散度相关的两个主成分,作为表征景观恢复性的关键指标。(5)在30年的恢复期中,研究区整体景观格局质量得到提升,但恢复缓慢,与风灾前依然相差较大。(6)多次强风干扰可以形成长白山西、南坡非标准的垂直带谱。     

正常椎间盘胶原的研究

腰椎间盘突出症是引起腰腿痛常见的原因。胶原作为椎间盘结构的主要成分,构成椎间盘的纤维框架,其类型与分布直接决定着椎间盘结构的强度和功能的稳定。本文利用溴化氰消化椎间盘胶原产生多肽,借助于梯度层析。SDS-PAGE及光密度定量扫描等对正常人椎间盘胶原进行了研究。结果表明:正常人椎间盘含Ⅰ型及Ⅱ型两种胶原,它们的分布呈明显而特征性的移行性变化:纤维环外层边缘以Ⅰ型胶原为主(83％),由外向内Ⅰ型胶原逐渐移行为Ⅱ型胶原,靠近髓核处以Ⅱ型胶原为主(72％);髓核中心含有Ⅱ型胶原。此为椎间盘的一个结构特性,以满足椎间盘的特殊功能的需要。     

海甘蓝种子成熟过程中脂肪酸含量以及脱落酸和山梨醇的效应

海甘蓝种子在成熟过程中,棕榈酸、硬脂酸和亚麻酸的含量不断下降,而十二碳烯酸和芥酸的含量呈上升趋势。选用开花后２５￣２７ｄ的海甘蓝幼胚分别在含不同浓度的ＡＢＡ或高渗透剂的培养基中培养１￣３ｄ,发现其各种脂肪酸的变化趋势和种子自然成熟过程中脂肪酸的变化相似,说明ＡＢＡ或高渗透剂可能是种子成熟过程中各种脂肪酸合成和相互转化所需的条件。     

海甘蓝种子成熟过程中脂肪酸含量以及脱落酸和山梨醇的效应

海甘蓝种子在成熟过程中,棕榈酸、硬脂酸和亚麻酸的含量不断下降,而二十碳烯酸和芥酸的含量呈上升趋势。选用开花后２５～２７ｄ的海甘蓝幼胚分别在含不同浓度的ＡＢＡ或高渗透剂的培养基中培养１～３ｄ,发现其各种脂肪酸的变化趋势和种子自然成熟过程中脂肪酸的变化相似,说明ＡＢＡ或高渗透剂可能是种子成熟过程中各种脂肪酸合成和相互转化所需的条件。     

汉防己甲素及克矽平时矽肺大鼠I型和Ⅲ型胶原mRNA的影响

汉防己甲素（汉甲）及克矽平是目前较为有效的抑制矽肺纤维化的药物,本文研究了其对胶原ｍＲＮＡ水平的影响。斑点杂交实验表明大鼠接尘６０天和１２０天后α１（Ⅲ）ｍＲＮＡ水平明显上升。经汉甲或克矽平治疗１个月域３个月后,胶原ｍＲＮＡ水平明显下降,原位杂交结果表明胶原ｍＲ－ＮＡ银颗粒与细胞性结节和增厚的肺泡壁的成纤维细胞分重事,汉甲或克矽平治疗后银颗粒数下降。提示汉甲及克矽平对矽肺进程中的胶原基因表达增强有     

Changes in the distribution of fibrillar collagens in the collateral and cruciate ligaments of the rabbit knee joint during fetal and postnatal development

Summary The collateral ligaments can be clearly distinguished in the 25-day fetal rabbit knee joint. Types I and V collagens are present in the extracellular matrix between the cells of the lateral and medial collateral ligaments and this distribution persists until the rabbit is skeletally mature. From 8 months onwards type III collagen is also present, particularly around the cells. Type I collagen mRNA is expressed by the cells from the 25-day fetal to 8-month-old adult ligament. The ligament sheath is composed of types III and V collagens. The cruciate ligaments are present between the femur and tibia in the 20-day fetus. The matrix is composed of types I and V collagens from the 25-day fetus until at 12- to 14-weeks postnatal, type III collagen appears in the pericellular regions together with type V. At 8 months and 2 years, the amount of type III collagen has increased. All the cells express the mRNA for type I collagen at 12- to 14-weeks, but only isolated cells express this mRNA at 8 months. Thus, both the collateral and cruciate ligaments undergo changes in their complement of collagens during postnatal development and ageing. The implications of these complex interactions of different types of collagen are discussed in relation to healing and the surgical replacement of torn ligaments by tendons.     

Lack of transformation of the collagen substratum in collagen lattice cultures

Human dermal fibroblasts were seeded into collagen lattices (tridimensional meshwork) of two preparations: (1) acid-extracted, (2) pepsin-digested-calf skin collagens. Lattices prepared with pepsin-digested collagen retracted faster during the first 2 days, then the two preparations gave the same contraction pattern. Lattices of both preparations were contracted for up to 23 days and their collagens submitted to CNBr treatment. The patterns of CB-peptides were found identical for all the incubation periods tested. There is no formation of cross-links during the contraction process.     

Quantitative Evaluation of Collagen Crosslinks and Corresponding Tensile Mechanical Properties in Mouse Cervical Tissue during Normal Pregnancy

The changes in the mechanical integrity of the cervix during pregnancy have implications for a successful delivery. Cervical collagens are known to remodel extensively in mice with progressing gestation leading to a soft cervix at term. During this process, mature crosslinked collagens are hypothesized to be replaced with immature less crosslinked collagens to facilitate cervical softening and ripening. To determine the mechanical role of collagen crosslinks during normal mouse cervical remodeling, tensile load-to-break tests were conducted for the following time points: nonpregnant (NP), gestation day (d) 6, 12, 15, 18 and 24 hr postpartum (PP) of the 19-day gestation period. Immature crosslinks (HLNL and DHLNL) and mature crosslinks (DPD and PYD) were measured using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). There were no significant changes in the total immature crosslink density (HLNL+DHLNL mol per collagen mol) throughout normal mouse gestation (range: 0.31–0.49). Total mature crosslink density (PYD+DPD mol per collagen mol) decreased significantly in early softening from d6 to d15 (d6: 0.17, d12: 0.097, d15: 0.026) and did not decrease with further gestation. The maturity ratio (total mature to total immature crosslinks) significantly decreased in early softening from d6 to d15 (d6: 0.2, d15: 0.074). All of the measured crosslinks correlated significantly with a measure of tissue stiffness and strength, with the exception of the immature crosslink HLNL. This data provides quantitative evidence to support the hypothesis that as mature crosslinked collagens decline, they are replaced by immature collagens to facilitate increased tissue compliance in the early softening period from d6 to d15.     

Influence of neutral salts on the hydrothermal stability of acid-soluble collagen

The thermal stability of acid-soluble collagens was studied by circular dichroism (CD) spectroscopy. Adult bovine dermal collagen (BDC), rat-tail tendon collagen (RTC), and calf skin collagen (CSC) were compared. Despite some variability in amino acid composition and apparent molecular weight, the CD spectra for helical and unordered collagen structures were essentially the same for all the sources. The melting of these collagens occurs as a two-stage process characterized by a pretransition (T _p) followed by complete denaturation (T _d). The characteristic temperatures vary with the source of the collagen; for mature collagens (BDC, RTC) T _p = 30°C and T _d = 36deg;C, and for CSC T _p = 34°C and T _d = 40°C. Neutral salts, NaCl or KCl, at low concentrations (0.02–0.2 M) appear to bind to the collagens and shift the thermal transitions of these collagens to lower temperatures.     

Development of tendon structure and function: regulation of collagen fibrillogenesis

In the tendon, the development of mature mechanical properties is dependent on the assembly of a tendon-specific extracellular matrix. This matrix is synthesized by the tendon fibroblasts and composed of collagen fibrils organized as fibers, as well as fibril-associated collagenous and non-collagenous proteins. All of these components are integrated, during development and growth, to form a functional tissue. During tendon development, collagen fibrillogenesis and matrix assembly progress through multiple steps where each step is regulated independently, culminating in a structurally and functionally mature tissue. Collagen fibrillogenesis occurs in a series of extracellular compartments where fibril intermediates are assembled and mature fibrils grow through a process of post-depositional fusion of the intermediates. Linear and lateral fibril growth occurs after the immature fibril intermediates are incorporated into fibers. The processes are regulated by interactions of extracellular macromolecules with the fibrils. Interactions with quantitatively minor fibrillar collagens, fibril-associated collagens and proteoglycans influence different steps in fibrillogenesis and the extracellular microdomains provide a mechanism for the tendon fibroblasts to regulate these extracellular interactions.     

Effect of pH on thermal stability of collagen in the dispersed and aggregated states (Short Communication)

Thermal stabilities of mature insoluble collagen, salt-precipitated fibrils of acid-soluble collagen and acid-soluble collagen in solution were compared as a function of acid pH. Both insoluble and precipitated collagens showed large parallel destabilization with decrease in pH, whereas the intrinsic stability of individual collagen molecules in dilute solution was comparatively unaffected.     

Molecular and biochemical aspects of nematode collagens.

Collagens are major structural proteins of nematode cuticles and basement membranes (basal laminae). The collagen proteins that form these structures differ in their biochemical and physical properties and are encoded by distinct gene families. Nematode basement membrane collagens are large proteins that show strong homology to basement membrane collagens of vertebrates. There appear to be 2 nonidentical basement membrane collagen genes in nematodes. Cuticle collagens are about one-sixth the size of basement membrane collagens and are encoded by a large family of 20-150 nonidentical genes. Cuticle collagens can be subdivided into 4 families based upon certain structural features in the proteins. The mature, extracellular forms of both types of collagen proteins are extensively cross-linked by disulfide bonds and are largely insoluble in the absence of a thiol-reducing agent. Cuticle collagens also are cross-linked by nonreducible covalent bonds that involve tyrosine residues. The experimental studies that have led to our current understanding of the structures of basement membrane and cuticle collagens are reviewed. Some previous questions about the physical properties of these proteins are reexamined in light of the primary sequence information now available for the proteins.     

Selective decrease of type I collagen synthesis in Fraser mice skin

Quantification and biosynthesis of type I and type III collagens were determined in skin of control and Fraser mice (CatFraser mutation), which exhibit a genetically determined cataract. Skin organ cultures were labelled with [3H]proline. Pepsin-solubilized collagens were studied using three different approaches: (a) differential salt precipitation at neutral pH, followed by SDS-polyacrylamide gel electrophoresis; (b) differential salt precipitation at acid pH followed by SDS-polyacrylamide gel electrophoresis. (c) CNBr peptide analysis. These methods gave consistent and reproducible results, indicating a selective decrease of type I collagen in Fraser mouse skin as compared to control mouse skin. Metabolic labelling of skin organ cultures showed a decreased specific radioactivity of hydroxy[3H]proline in type I collagen of Fraser mouse skin. The concordant results of these experiments suggest a genetically determined alteration of interstitial collagen metabolism in the Fraser mutation apparently specifically concerning the expression of type I collagen gene(s).     

The degradation rates of type I, II, and III collagens by tadpole collagenase

The degradation rates of type I, II, and III collagens by tadpole collagenase were studied by measuring the viscosity of the solution and the contents of alpha chains and alpha A chains of collagen, using SDS-polyacrylamide gel electrophoresis followed by densitometric analysis of the separated peptide bands. An empirical parameter was derived from the viscosity, and was shown to change in parallel with the content of alpha chains upon incubation with tadpole collagenase almost to the stage of complete digestion of collagen. Linear plots of parameters reflecting the concentration of intact collagen molecules against time were obtained, indicating the degradation to be pseudo-first order. The first-order rate constants for the degradation of Type I, II, and III collagens with tadpole collagenase at 30, 25, and 20 degrees C gave activation energies of 60 kcal/mol for Type III collagen and 40 kcal/mol for Type I and II collagens. There appeared to be a dependency of the degradation rates on the conformation of the collagen molecules (which is affected by temperature).