A small angle light scattering device for planar connective tissue microstructural analysis

The planar fibrous connective tissues of the body are composed of a dense extracellular network of collagen and elastin fibers embedded in a ground matrix, and thus can be thought of as biocomposites. Thus, the quantification of fiber architecture is an important step in developing an understanding of the mechanics of planar tissues in health and disease. We have used small angle light scattering (SALS) to map the gross fiber orientation of several soft membrane connective tissues. However, the device and analysis methods used in these studies required extensive manual intervention and were unsuitable for largescale fiber architectural mapping studies. We have developed an improved SALS device that allows for rapid data acquisition, automated high spatial resolution specimen positioning, and new analysis methods suitable for large-scale mapping studies. Extensive validation experiments revealed that the SALS device can accurately measure fiber orientation for up to a tissue thickness of at least 500 μm to an angular resolution of∼1^o and a spatial resolution of±254 μm. To demonstrate the new device’s capabilities, structural measurements from porcine aortic valve leaflets are presented. Results indicate that the new SALS device provides an accurate method for rapid quantification of the gross fiber structure of planar connective tissues.     

Construction of a stable nipple valve with processed dermal sheep collagen for continent ileostomy and urostomy

Summary Complications of the nipple valve system used for continent urostomy and ileostomy basically consist of incomplete (or complete lack of) adhesion of the invaginated serosal surfaces of the valve. A novel concept in fixation of the valve by means of the intussusception of a newly developed biomaterial (processed dermal sheep collagen; PDSC) was tested. The implanted PDSC is characterized by induction of fibroblast invasion and formation of new collagen fibers, initial high tensile strength, bio-inertion and (slow) biodegradation. It was implanted between the serosal surfaces of the invagination in 14 dogs without the application of the commonly used staples and synthetic mesh. Good permanent fixation was obtained in all cases after the PDSC had been sutured in place. As the observation time advanced up to 2 years, an increased amount of newly formed collagen was seen anchoring the serosal surfaces firmly together via the implanted PDSC with apparent slow degradation. In none of the test animals did complications accur. The first clinical trial was successful.This study was sponsored by the Preventie fonds     

The effects of brisk walking on markers of bone and calcium metabolism in postmenopausal women

Weight-bearing exercise has been shown to maintain or increase bone mass in younger as well as older individuals but the mechanisms by which mechanical loading affects bone metabolism are not known in detail. Twelve postmenopausal women participated in a single bout of brisk walking (50% of VO_{2 max}) for 90 minuttes. Calciotropic hormones and markers of type I collagen formation (PICP) and degradation (ICTP) were measured before the exercise, and 1, 24, and 72 hours following the exercise. Total body bone mineral content (BMC) and density (BMD) were measured by dual energy X-ray absorptiometry (DXA). Brisk walking did not induce any significant changes in the concentrations of ionized calcium, parathyroid hormone (PTH), calcitonin, or osteocalcin. A significant increase of PICP was noted 24 and 72 hours (P<0.01) after exertion and a significant decrease in the concentration of serum ICTP at 1 hour (P<0.05) was followed by an increase at 72 hours (P<0.001). There was no significant difference between the increases in the concentrations of PICP and ICTP at 72 hours. Strong inverse correlations between the basal levels of PTH and BMD (r=−0.78;P<0.01) as well as between osteocalcin and BMD (r=−0.83;P<0.01) were noticed. The changes in serum levels of bone collagen markers indicate an altered bone collagen turnover due to this moderate endurance exercise. The results also support the fact that serum levels of PTH as well as those of osteocalcin are associated with total body BMD in postmenopausal women.     

血小板源生长因子对人血管成纤维细胞DNA及胶原蛋白合成的影响

目的:观察血小板源生长因子对培养的人血管成纤维细胞DNA及胶原蛋白合成的影响。方法:采用培养的人血管成纤维细胞,应用 [³H]-TdR和 [³H]-脯氨酸掺入的方法,观察血小板源生长因子-BB对人血管成纤维细胞DNA合成以及胶原蛋白合成的影响。结果:血小板源生长因子-BB可促进静止状态的人血管成纤维细胞DNA及胶原蛋白的合成,在 30μg/L浓度时DNA及胶原蛋白的合成达到高峰,DNA及胶原蛋白分别于 2 4h和 36h合成最为显著。结论:血小板源生长因子-BB可明显促进培养的人血管成纤维细胞DNA及胶原蛋白的合成     

肺癌细胞外基质的表达与临床病理的关系

目的探讨原发性肺癌层粘蛋白（Ｌａｍｉｎｉｎ,ＬＮ）、纤维连接蛋白（ｆｉｂｒｏｎｅｃｔｉｎ,ＦＮ）和Ⅳ型胶原的表达与临床病理的关系。方法采用免疫组化ＬＳＡＢ法检测１８４例肺癌标本中ＬＮ、ＦＮ和Ⅳ型胶原的表达。结果ＬＮ及Ⅳ型胶原在中、高分化的肺鳞癌中的表达均明显强于低分化组（Ｐ＜００１）,在有无淋巴结转移两组间的表达差异均具显著性（Ｐ＜００５）;肺鳞癌５年以上生存组ＬＮ、Ⅳ型胶原的表达明显高于０５年内死亡组（Ｐ＜００１）,ＦＮ的表达亦有差异（Ｐ＜００５）。肺腺癌的５年以上生存组中ＦＮ、Ⅳ型胶原的表达均强于０５年内死亡组（Ｐ＜００５,００１）。结论ＬＮ和Ⅳ型胶原的表达与肺鳞癌的组织学分级和淋巴结转移有关;ＬＮ、ＦＮ、Ⅳ型胶原的表达均可作为评估肺鳞癌预后的指标,而腺癌的预后仅与ＦＮ、Ⅳ型胶原的表达有关。     

Prestress Due to Dimensional Changes Caused by Demineralization: A Potential Mechanism for Microcracking in Bone

Microcracking in bone due to internal strains caused by mineralization is a possible mechanism of damage. Similar damage can be seen in other biological composites such as trees experiencing growth-related prestresses. Dimensional changes in cortical bone due to demineralization and experimental glycation were studied to test whether mineralization-related prestrains are consistent with observed microcracking patterns in bone. A microscopy technique that enables wet measurements of length and angle of milled bone specimens was used. Demineralization of bovine and human bones caused significant anisotropic changes in tissue size. Dimensional changes due to demineralization in bovine bone were prevented or reduced when collagen cross linking was increased by glycation. The dimensional changes of bone caused by demineralization are consistent with the hypothesis that mineralization-caused stresses in remodeling tissue can cause microcracks. © 2002 Biomedical Engineering Society. PAC2002: 8719Rr     

Autologous rib perichondrial grafts in experimentally induced osteochondral lesions in the sheep-knee joint: Morphological results

Summary The purpose of the present study was to examine the fate of autologous perichondrial grafts after transplantation into cartilage lesions in weight-bearing joints. Osteochondral lesions were made in the articular surface of knee joints in 36 sheep. The defects were filled with autologous rib perichondrial grafts which were secured by either collagen sponges (12 animals) or fibrin glue (12 animals). Defects without perichondrial grafts served as controls (12 animals). Following 1 week of immobilization of the operated leg, the plaster was removed and the animals were allowed to move freely. Animals were sacrificed after 4, 8, 12 and 16 weeks. The grafts were removed and investigated histologically. In contrast to weight-bearing areas and control defects, hyaline-like cartilage formation was seen in non-weightbearing areas after 4 weeks. This newly formed cartilage revealed strong metachromasia following staining with acidic toluidine blue and reacted positively with periodic acid-Schiff, indicating de novo synthesis of proteoglycans and glycoproteins. Scanning electron microscopy and examinations with polarized light confirmed a hyaline cartilage-like architecture for the surface area as well as for the fibre orientation of the whole graft. Enzyme histochemistry for alkaline and acid phosphatase activity showed positive reactivity only at the base of the transplants.     

FD-1冷冻干燥机的研制及生物材料的冷冻干燥

观察自制冷冻干燥机冷冻干燥生物材料的效果。采用 R5 0 2压缩机和制冷剂制成 FD- 1冷冻干燥机。本实验冷冻干燥了胶原海绵、菌种及去纤酶。在冻干箱负载或空载情况下蒸发冷凝器温度均可达到 - 4 5℃ ,小冰箱可达到 - 30℃ ,冻干的胶原海绵具有许多孔洞的结构 ,冻干的菌种和去纤酶性能保持良好。 FD- 1冷冻干燥机适用于生物样品中小批量的冷冻干燥     

糖尿病大鼠创面愈合过程中成纤维细胞增殖及Ⅰ型胶原合成减少

目的：观察链脲佐菌素诱导的大鼠糖尿病复合创伤修复过程中成纤维细胞增殖与胶原合成的变化。 方法： 实验采用Wistar大鼠112只，随机分对照组和模型组。模型组大鼠腹腔注射链脲佐菌素（STZ）55 mg/kg，3周后各组动物复合背部2.04 cm²全厚皮切除形成伤口。观察创面愈合时间和愈合率；采用HE染色和免疫组化法观察成纤维细胞和增殖细胞核抗原(PCNA)表达水平；采用苦味酸-天狼星红染色和图像分析技术观察创面Ⅰ、Ⅲ型胶原含量及Ⅰ/Ⅲ型比值。 结果： STZ诱发的糖尿病大鼠复合创伤后创面的愈合时间为(27.13±1.81)d，明显长于对照组（15.25±1.67）d，P<0.01；模型组在创伤第3、7和15 d创面愈合率明显低于对照组，分别P<0.01；在3、5、7和9 d模型组创面成纤维细胞数量和PCNA表达也明显少于对照组，分别P<0.05和P<0.01。两组创面在不同时点上Ⅰ型胶原分布均呈递增趋势，但对照组明显多于模型组，分别P＜0.05；尽管对照组在创伤3、7 d Ⅲ型胶原含量高于模型组，但在创伤3、7和11 d模型组Ⅰ/Ⅲ胶原比值都明显低于对照组，分别P＜0.01。 结论： STZ可能通过影响创面细胞增殖和创面胶原合成，从而导致创面愈合迟缓。     

葡甘聚糖-胶原蛋白-壳聚糖共混膜(I)

用溶液共混法制备了葡甘聚糖-胶原蛋白-壳聚糖(KCCS)共混膜。并用FT-IR,X-RD,SEM及透光率表征了膜的结构,同时测试了膜的抗张强度、断裂伸长率、吸水率、透水汽性、渗透性和吸附性。结果表明:共混膜中葡甘聚糖、胶原蛋白及壳聚糖之间存在着强烈的相互作用和良好的相容性,三者共混明显改善了纯聚合物和二元膜的性能。以共混膜为载体培养内皮细胞,发现共混膜具有良好的细胞相容性,预示着共混膜可作为潜在的组织工程支架材料。