We wanted to know if the control of tissue architecture to achieve function extends down to the nanoscale level of the individual, cable-like collagen fibrils

Using tendons from young adult bovine forelimbs, we performed stress-strain experiments on single collagen fibrils extracted from tendons with positional function, and tendons with energy storing function. Collagen fibrils from the two tendon types, which have known differences in intermolecular crosslinking, showed numerous differences in their responses to elongation. Unlike those from positional tendons, fibrils from energy storing tendons showed high strain stiffening and resistance to disruption in both molecular packing and conformation, helping to explain how these high stress tissues withstand millions of loading cycles with little reparative remodeling. Functional differences in load-bearing tissues are accompanied by important differences in nanoscale collagen fibril structure.Conflict of interest statement: The authors declare no competing interests.Changes in morphometric parameters and the characteristics of collagen following thyroxine and thiourea treatments in young male garden lizards.

Administration of both thyroxine (1 microgram/g body wt) and thiourea (0 mg/10 g body wt) to young male garden lizards for a period of 2 weeks led to changes in morphometric/biochemical parameters. Percentages of increase in body weight and snout-to-vent length of thyroxine-treated lizards during this period were significantly lower than the percentages of increase observed in control lizards. Thiourea-induced inhibition of increase in body weight was marginal but not significant statistically. The total collagen content of tendons decreased upon thyroxine treatment and increased following thiourea administration. Thyroxine treatment led to an increase in salt solubility of bone and skin collagens and thiourea showed a reverse effect. On  the ordinary squalane cleanser , the acid solubility of tendon collagen increased after thyroxine administration and decreased following thiourea treatment.[The influence of angiotensin-converting enzyme inhibitors on collagen content of the aorta wall in experimental hypercholesterolemia].

In atherosclerosis numerous qualitative and quantitative changes in connective tissue metabolism parameters in serum and aorta occur. In atherosclerosis there is an enhanced activity of local renin-angiotensin systems. It leads to overexpression of ANG II, both in serum and arterial wall. ANG II stimulates SMC to over-synthesize the collagens type I and III. Hyper-cholesterolemia is a form of metabolic injury which can both induce phenotypic change of SMC and activate RA system in arterial wall. ACEI lower the accumulation of collagens type I and III, and enhance elastin content in arterial wall in experimental hypertension. The aim of this study was to assess the influence of captopril, enalapril and quinapril on connective tissue metabolism of the aorta in experimental hyper-cholesterolemia.

64 male New Zealand rabbits were used. Animals were fed with standard fodder, special diet (1% cholesterol content) or special diet + tested ACEI. Two doses of ACE inhibitors were used: 1st--equivalent to doses applied to human subjects (in mg/kg of body weight), 2nd--dose 10 times higher. The animals were divided into 8 equal groups: K--standard fodder, B--special diet, C1, C2--special diet + captopril in doses 2 and 25 mg/kg/24 hours, respectively, E1, E2--special diet + enalapril in doses 05 and 7 mg/kg/24 hours, respectively, Q1 i Q2--special diet + quinapril in doses 05 and 7 mg/kg per day, respectively. The experiment lasted for 6 months. After 24 weeks the animals were sacrificed and aortae were excised for collagens assay. The statistical analysis was performed using ANOVA, followed by LSD test; p < 05 was considered statistically significant.

The aorta collagens content of cholesterol-fed rabbits significantly increased. The tested ACEI (captopril, enalapril in both doses and quinapril in lower dose) had a preventive effect against the increase of aorta collagen content.[Effects of fasting on skin and bone collagen metabolism of rats].Collagenous crystalloids in pleomorphic adenoma of the parotid gland.In vitro analysis of differential expression of collagens, integrins, and growth factors in cultured human chondrocytes.of Baden-Württemberg/Hessen, Ruprecht-Karls-University Heidelberg, Theodor-Kutzer-Ufer, D-68135 Mannheim, Germany. OBJECTIVES: Tissue engineering represents a promising method for the construction of autologous chondrogenic grafts for reconstructive surgery.

In cultured chondrocytes, the dedifferentiation and proliferation of the cells are critical factors that influence the generation of transplants. The aim of our study was to find and characterize markers for cell proliferation and dedifferentiation in cultured chondrocytes.STUDY DESIGN AND SETTING: Human chondrocytes were isolated from septal cartilage and held in primary cell culture. Cells were harvested after 1, 6, and 21 days. The differentiation of the cells was investigated with bright-field microscopy, the expression patterns of various proteins using immunohistochemistry, and the expression of distinct genes with the microarray technique.RESULTS: The chondrocytes showed a strong proliferation. After  ordinary squalane cleanser  and 21 days, collagen 9 and 10 were downregulated; collagen 11 was activated.