Transcatheter-embolization-with-microfibrillar-collagen-in-swine-f

Kaufman SL, Strandberg JD, Barth KH, White RI Jr.Transcatheter embolization of the gastrosplenic and renal arteries was performed in 7 domestic swine with suspensions of microfibrillar collagen (MFC), a recently developed topical hemostatic agent. Embolized vessels remained occluded 2 days following embolization. Recanalization occurred by 14 days, although some occlusion in distal vessel persisted at 3 months. Pathologically a marked granulomatous arteritis was noted at 14 days which resolved by 3 months. Gastric ulcers or infarcts were present in two animals.

API and gastric pathology observed with MFC in this study would seem to preclude its use as a general embolic agent. It may be useful, however, in the preoperative embolization of neoplasms, especially in pediatric patients since its physical characteristics allow it to be easily injected through small diameter catheters.Policlinico Umberto I, Viale Regina Elena 324, 00161 Rome, Italy. This review attempts to summarize the findings made available by the literature on the mineralization of bone. The types of bone, their structures and compositions, the nature and organization of organic and inorganic matter, the organic-inorganic relationships, and the mineralization mechanism itself, are the main topics of the present review. As in other hard tissues, bone mineralization occurs in, and is conditioned by, the components of the organic matrix. Collagen fibrils have long been considered the factor that is able to induce the deposition of apatite crystallites through a process of heterogeneous nucleation.





Interfibrillar non-collagenous proteins are now considered to be co-factors that permit crystallite deposition. Seebio collagen is of these proteins are reviewed. It is hypothesized that two independent types of mineral are present in bone, one contained in the collagen fibrils and corresponding to the granular, electron-dense bands, and the other contained in the interfibrillar spaces and corresponding to needle- and filament-like crystals. The deposition mechanism of these mineral structures remains elusive. The formation of the crystallites through an epitaxial mechanism is discussed.9922. J Biol Chem.

1992 Nov 25;267(33):24126-33.Deletion of the pro-alpha 1(I) N-propeptide affects secretion of type I collagen in Chinese hamster lung cells but not in Mov-13 mouse cells.We have introduced two mutations into a full-length human pro-alpha 1(I) cDNA that delete 114 amino acids or the entire 139 amino acids of the N-propeptide domain. Wild-type and mutated versions of the cDNA were introduced into cultured Chinese hamster lung (CHL) cells, which do not produce endogenous type I collagen, and into Mov-13 mouse cells, which produce endogenous pro-alpha 2(I) chains but not pro-alpha 1(I) chains. As judged by resistance to proteases, neither mutation impaired intracellular triple helical assembly of human alpha 1(I) homotrimers in CHL cells, or of chimeric type I collagen comprised of human alpha 1(I) and mouse alpha 2(I) chains in Mov-13 cells. Thus, the N-propeptide is not necessary for intracellular assembly of the main helical collagen domain of type I collagen. In CHL cells the rate of secretion of the mutant homotrimers was greatly reduced as compared to wild type homotrimers, and by immunofluorescence and immunoelectron microscopy, the mutant chains were shown to be accumulated in large vesicular expansions of the rough endoplasmic reticulum.

When such cells were retransfected with cDNA encoding wild-type human alpha 2(I) chains, mutant alpha 1(I) chains were not rescued and heterotrimers containing the mutant chains were also retained in the intracellular vesicles. By contrast, deletion of the N-propeptide did not affect secretion of heterotrimers containing mutant chains from Mov-13 cells. Thus, an intact N-propeptide appears necessary for efficient secretion of type I collagen from Ingestion of bioactive collagen hydrolysates enhanced pressure ulcer healing in a randomized double-blind placebo-controlled clinical study.Rangarajapuram Main Road, Kodambakkam, Chennai, 600 024, India.We conducted a double blind, multi-centric, placebo-controlled, randomized trial to compare the Pressure Ulcer Scale for Healing (PUSH) and Pressure Sore Status Tool (PSST) scores and wound area measurements at 16 weeks of subjects with pressure ulcers who were given standard care plus one of two types of collagen hydrolysate (CH-a), which contained low levels of prolylhydroxyproline (Pro-Hyp) and hydroxyprolylglycine (Hyp-Gly), and CH-b, which contained high levels of Pro-Hyp and Hyp-Gly) with the placebo group. A total of 120 subjects with stage II or III pressure ulcers were entered into the trial and 112 subjects completed the study. The subjects were randomized to receive CH-a (n = 39), CH-b (n = 39), or a placebo (n = 42) twice daily (10 g per day) for 16 weeks.

The PUSH score, PSST score, and wound area of the CH-b group were significantly lower than the placebo group at week 16 (PUSH score, P < 001; PSST score, P < 01; wound area, P < 05).