Prolyl and lysyl hydroxylases in collagen synthesis

Collagens are the most abundant proteins in the extracellular matrix. They provide a framework to build organs and tissues and give structural support to make them resistant to mechanical load and forces. Several intra‐ and extracellular modifications are needed to make functional collagen molecules, intracellular post‐translational modifications of proline and lysine residues having key roles in this. In this article, we provide a review on the enzymes responsible for the proline and lysine modifications, that is collagen prolyl 4‐hydroxylases, 3‐hydroxylases and lysyl hydroxylases, and discuss their biological functions and involvement in diseases.     

Er:YAG激光桩道预处理的研究进展

本文回顾了Er:YAG激光活化根管冲洗技术的最新研究进展,包括光子诱导光声流(photon initiated photoacoustic streaming,PIPS)技术和冲击波增强发射光声流(shock wave enhanced emission photoacoustic streaming,SWEEPS)技术,探讨Er:YAG激光预处理桩道的原理、优点以及对纤维桩粘接强度的影响,以期为临床选择适宜的桩道处理方法提供新思路。     

Optimization of immunohistochemical detection of collagen type II in osteochondral sections by comparing decalcification and antigen retrieval agent combinations

Bone containing tissues such as osteochondral joint are resistant to routine tissue processing, therefore require decalcification. This technique causes removal of mineral salts, but in the process may macerate the organic tissue, hence the need for tissue fixation. Such severe processing demands careful antigen retrieval to necessitate optimal staining. The aim of our study was to compare five different antigen retrieval protocols (heat retrieval and protein digestion) following decalcification of rabbit knee joints using two different techniques (20% formic acid and 10% ethylenediamine-tetra acetic acid: EDTA). Osteochondral sections were compared based on time required for decalcification, ease of sectioning, morphological integrity using HE staining and antigen preservation (Collagen type II) using immunohistochemistry. The two decalcification solutions did not impair the tissue morphology and ease of sectioning. Joints processed with formic acid decalcified four times faster than EDTA. Among the five antigen retrieval approaches, maximal collagen II uptake with minimal nonspecific staining was found with protein digestion (pronase and hyaluronidase) in both formic acid and EDTA sections. For osteo-chondral sections, we recommend using 10% EDTA for decalcification and pronase plus hyaluronidase for antigen retrieval if maintaining tissue morphology is crucial, whereas if time is of the essence, 20% FA with pronase plus hyaluronidase is the faster option while still preserving structural integrity. Clin. Anat. 33:343–349, 2020. © 2019 Wiley Periodicals, Inc.     

桑根酮C对博莱霉素诱导小鼠肺纤维化改善作用及机制研究

目的观察桑根酮C对博莱霉素诱导的小鼠肺纤维化的影响,并探讨其可能的作用机制。方法 C57BL/6小鼠随机分为4组,即假手术组、模型组和桑根酮C(100、50 mg/kg)组,每组20只。假手术组小鼠气管内注射生理盐水,模型组小鼠气管内注射博莱霉素诱导肺纤维化模型。术后第4天开始给药,连续给药28d后检测小鼠呼吸功能;检测肺内羟脯氨酸含量;HE染色观察肺内炎症表现;Masson染色观察肺内胶原活性;免疫组化法检测肺内转化生长因子-β1(TGF-β1)蛋白表达量;免疫蛋白印迹法检测肺内α平滑肌肌动蛋白(α-SMA)、核转录因子-κB p65(NF-κB p65)、磷酸化的核转录因子-κB p65(p-NF-κB p65)、Ⅰ型胶原和Ⅲ型胶原表达量。结果与模型组比较,桑根酮C能够改善经博莱霉素诱导形成肺纤维化后小鼠的呼吸功能,能够明显降低肺内羟脯氨酸含量,明显减轻肺内炎症和胶原沉积,肺内TGF-β1、α-SMA、NF-κBp65、p-NF-κBp65、Ⅰ型胶原和Ⅲ型胶原蛋白表达量明显降低。结论桑根酮C能够明显改善博莱霉素诱导小鼠肺纤维化,改善呼吸功能,其机制可能与抑制TGF-β1过表达和降低炎症转录因子NF-κB及磷酸化表达有关。     

Histomorphologic Characterization of Noncarious and Caries-Affected Dentin/Adhesive Interfaces

PURPOSE: The purpose of this study was to compare the dentin/adhesive interfacial characteristics when bonding to noncarious as well as caries-affected dentin. MATERIALS AND METHODS: Seven extracted, unerupted, third molars were sectioned into halves. Artificial caries was created on one-half of each tooth, leaving the other half as a control. Dentin surfaces were treated with UNO adhesive according to the manufacturer's instructions for the wet-bonding technique and under environmental conditions present in the oral cavity. Dentin/adhesive interface sections of each half-tooth were stained with Goldner's trichrome, a classic bone stain, and examined using light microscopy. The width of exposed collagen was measured directly from photomicrographs, and adhesive penetration was analyzed qualitatively. RESULTS: The degree and extent to which the adhesive encapsulated the demineralized dentin matrix were reflected in the color difference in the stained sections with the noncarious dentin sections showing a degree of collagen encapsulation superior to that of the caries-affected dentin sections. The overall mean widths of exposed collagen were significantly (p < or = .05) greater at the caries-affected dentin/adhesive interface, 8.6 (1.7) microm, as compared with those at the noncarious dentin/adhesive interface, 6.0 (1.5) microm. CONCLUSIONS: The morphologic characteristics of the caries-affected dentin/interface suggest an increase in the exposed collagen zone and a decrease in the quality of the adhesive infiltration when compared with noncarious dentin. The evidence suggests that dentin substrate characteristics have a significant effect on the dentin/adhesive interface structure.