Design and evaluation of ocular hydrogel containing combination of ofloxacin and dexamethasone for the treatment of conjunctivitis

Abstract Conjunctivitis is an inflammation of the conjunctiva, which covers the white part of the eyeball. It can be caused by allergies, bacterial or viral infection. In situ hydrogels are three-dimensional hydrophilic cross-linked network of polymers. In situ hydrogel provided better therapeutic index when compared to conventional treatment. The present work describes the formulation and evaluation of ofloxacin and dexamethasone based on the concept of pH triggered in situ gelation. Carbopol 934p was used as the gelling agent in combination with HPMC, as a viscosity-enhancing agent, benzalkonium chloride as preservative, sodium chloride as tonicity adjusting agent. The prepared formulations were liquid at the low pH and underwent rapid transition into viscous gel at the pH of the tear fluid. Formulations were evaluated for various rheological, in vitro and in vivo release characteristics. Infrared spectroscopy studies showed that there were no interactions between the drug and polymers. Viscosity of the prepared hydrogels lies in the optimum range and drug was released up to 85 % as the end of 13 h. The prepared in situ hydrogel was sterile, non-irritant to the eye. The present study indicated that it is possible to develop safe and physiologically effective in situ hydrogel which is patient compliant.

Properties of decellularized rabbit carotid artery with two different cross-linked technologies: A comparative study / 中南大学学报(医学版)

Objective:To compare the properties between decellularized rabbit carotid artery with different cross-linked technologies.Methods:The decellularized rabbit carotid arteries were randomly divided into a photo-oxidation group and a procyanidins group.One group was cross-linked with photo-oxidation and the other group was cross-linked with procyanidins.The in vitro or in vivo properties of the two groups were evaluated by testing heat-shrinking temperature,max tensile strength and the max elongation or by testing tissue structure,inflammatory reaction and calcification degree.Results:The heat-shrinking temperature,max tensile strength and the max elongation were similar in the two groups (P＞0.05).The tissue structure and inflammatory reaction were also similar in the two groups.Mthough the result of Von-Kossa calcium salt stain was slightly different,the calcium content was lower in the procyanidins group than that in the photo-oxidation group (P＜0.05).Conclusion:The grafts by two cross-linked technologies show excellent mechanical capability,lower immunogenicity,good biological stability and anti-calcification ability.The procyanidins group shows a better anti-calcification property than the photo-oxidation group.

The Role of the Lysyl Oxidases in Tissue Repair and Remodeling: A Concise Review

Tissue injury provokes a series of events containing inflammation, new tissue formation and tissue remodeling which are regulated by the spatially and temporally coordinated organization. It is an evolutionarily conserved, multi-cellular, multi-molecular process via complex signalling network. Tissue injury disorders present grievous clinical prob-lems and are likely to increase since they are generally associated with the prevailing diseases such as diabetes, hyper-tension and obesity. Although these dynamic responses vary not only for the different types of trauma but also for the different organs, a balancing act between the tissue degradation and tissue synthesis is the same. In this process, the degradation of old extracellular matrix (ECM) elements and new ones' synthesis and deposition play an essential role, especially collagens. Lysyl oxidase (LOX) and four lysyl oxidase-like proteins are a group of enzymes capable of catalyzing cross-linking reaction of collagen and elastin, thus initiating the formation of covalent cross-links that insolubilize ECM proteins. In this way, LOX facilitates ECM stabilization through ECM formation, development, maturation and remodeling. This ability determines its potential role in tissue repair and regeneration. In this review, based on the current in vitro, animal and human in vivo studies which have shown the significant role of the LOXs in tissue repair, e.g., tendon regeneration, ligament healing, cutaneous wound healing, and cartilage remodeling, we focused on the role of the LOXs in inflammation phase, proliferation phase, and tissue remodeling phase of the repair process. By summarizing its healing role, we hope to shed light on the understanding of its potential in tissue repair and provide up to date therapeutic strategies towards related injuries.

Biomechanical Analysis of a Pedicle Screw-Rod System with a Novel Cross-Link Configuration

STUDY DESIGN: The strength effects of a pedicle screw-rod system supplemented with a novel cross-link configuration were biomechanically evaluated in porcine spines. PURPOSE: To assess the biomechanical differences between a conventional cross-link pedicle screw-rod system versus a novel cross-link instrumentation, and to determine the effect of the cross-links. OVERVIEW OF LITERATURE: Transverse cross-link systems affect torsional rigidity, but are thought to have little impact on the sagittal motion of spinal constructs. We tested the strength effects in pullout and flexion-compression tests of novel cross-link pedicle screw constructs using porcine thoracic and lumbar vertebrae. METHODS: Five matched thoracic and lumbar vertebral segments from 15 porcine spines were instrumented with 5.0-mm pedicle screws, which were then connected with 6.0-mm rods after partial corpectomy in the middle vertebral body. The forces required for construct failure in pullout and flexion-compression tests were examined in a randomized manner for three different cross-link configurations: un-cross-link control, conventional cross-link, and cross-link passing through the base of the spinous process. Statistical comparisons of strength data were analyzed using Student's t-tests. RESULTS: The spinous process group required a significantly greater pullout force for construct failure than the control group (p=0.036). No difference was found between the control and cross-link groups, or the cross-link and spinous process groups in pullout testing. In flexion-compression testing, the spinous processes group required significantly greater forces for construct failure than the control and cross-link groups (p<0.001 and p=0.003, respectively). However, there was no difference between the control and cross-link groups. CONCLUSIONS: A novel cross-link configuration that features cross-link devices passing through the base of the spinous processes increased the mechanical resistance in pullout and flexion-compression testing compared to un-cross-link constructs. This configuration provided more resistance to middle-column damage under flexion-compression testing than conventional cross-link configuration.

Aplicação de transglutaminase microbiana em produtos cárneos processados com teor reduzido de sódio / Application of microbial transglutaminase in processed meat products with reduced content of sodium

O presente artigo compreende uma revisão sobre a aplicação da transglutaminase de origem microbiana (MTGase) em produtos cárneos, elaborados com teor reduzido de sódio. A MTGase tem se mostrado muito eficiente em promover pontes cruzadas entre proteínas, favorecendo a coesão em produtos reestruturados e melhorando a força de géis em produtos cárneos emulsionados, contribuindo para a melhoria de textura e preservando o sabor dos produtos. Tradicionalmente, o cloreto de sódio (NaCl) é adicionado às massas cárneas por desempenhar um papel-chave na solubilização das proteínas miofibrilares. No entanto, o excesso desse mineral tem sido associado aos altos índices de problemas de saúde, como a hipertensão arterial. Como reação a este cenário, a sociedade científica e indústrias ligadas ao setor cárneo têm buscado alternativas que possam atuar na redução do sódio nesses alimentos. Na presente revisão, são relatados estudos recentes sobre a aplicação da MTGase em diversos produtos de origem cárnea, elucidando a importância desse coadjuvante de tecnologia para a pesquisa científica e a aplicação industrial na área de produção de alimentos de conveniência e mais saudáveis.

This article includes a review of the application of microbial transglutaminase (MTGase) in meat products prepared with reduced-sodium. The MTGase has shown to be very efficient in promoting protein cross-bridges, favoring the cohesion restructured products and improving the strength of gels inemulsified meat products, contributing to preserve and improve their texture and flavor. Traditionally sodium chloride (NaCl) is added to pasta cárneas to play a key role in the solubilization of the myofibrillar proteins. However, the excess of this mineral has been linked to high rates of health problems as hypertension. In response to this scenario, scientific society and industries connected to the meat industry has sought alternatives that can acte to reduce the sodium in these foods. In this review, recent studies are reported on the application of MTGase in various products of meat mixture, elucidating the importance of supporting technology for scientific research and industrial application in the production of convenience healthier foods.

Assessment for the stability of fracture thoracic lumber spine(T11~L3) fixed with crossbar equipped pedicle screws / 医用生物力学

Objective To determine the stability of fracture thoracic lumber spine (T11~L3) fixed with crossbar equipped pedicle screws. MethodThe thoracic lumber spine segments (T11~L3) were obtained from calves. A wedge cut was performed on L1 vertebral body to produce a model resembling severe vertebral compressive fracture. Some of the fracture spine segments were fixed with pedicle screws with and without crossbar. Thus, 4 types of spine segments were available: (1) normal segments; (2) unfixed fracture; (3) fracture fixed with crossbar equipped pedicle screws and (4) fracture fixed with pedicle screws without crossbar. The segmental stability was determined by measuring the range of motion (ROM) at directions of flexion/extension, left/right axial rotation and left/right lateral bending using a three dimensional laser scanner. Each ROM was standardized into a stability potential index (SPI) for the comparison among 4 groups. ResultsCompared to unfixed fracture, both fixations significantly increase stability of injuried specimens at each motion direction. The stability of injured segment fix with crossbar equipped pedicle screws is higher than that fixed without crossbar, but the difference does not reach statistically significant. ConclusionsPedicle screw fixation can significantly increase the stability of fracture spine. However, crossbar may not play a further role in raising fixative stability.

In vivo recellularization of decellularized vascular scaffolds cross-linked with anti-CD34 antibody / 第二军医大学学报

Objective: To evaluate the role of decellularized vascular scaffolds coated with anti-CD34 antibodies in capturing endothelial progenitor cells from the circulation to participate in recellularization. Methods: Fresh caprine forelimb arteries were treated with repeated frozen/thawing, ultrahigh pressure and SDS to prepare decellularized vascular scaffolds. After reaction with photochemical crosslinker SANPAH, anti-rabbit CD34 was coated onto the decellularized vascular scaffolds using ultraviolet ray. Twenty New Zealand white rabbits were performed for right lower-abdominal pedicled skin flap, which were supplied by branches of femoral artery. Whole defects (1 cm) were made in femoral arteries and end-to-end anastomosis repaired by 10 cross-linked and 10 non-cross-linked scaffolds in experimental group and control group, respectively. The patency of the pedicle was observed through color and appearance of the flap postoperatively. After transplantation, patency rate and cell seeding were detected by Doppler, DSA, and pathological test. Results:. Flaps of the experimental group had good blood supply after transplantation, while swelling and necrosis could be found in the control group. Doppler and DSA showed that the 7 of 10 cross-linked scaffolds remained patent for 4 weeks and there was no stenonsis, but all the scaffolds were obstructed in the control group after 1 week. Hematoxylin and eosin staining revealed that the inner layers of cross-linked scaffolds were partly covered with endothelial cells four weeks later, and there was no noticeable stenosis. In contrast, thrombosis formation was noticed in the control group and there was no cell coverage one week after operation. Conclusion: Cross-linked scaffolds with anti-CD34 antibodies are superior to bare scaffolds in early postoperative anticoagulation and patency.

Effects of Soy Protein and Isoflavones on Bone Markers and Hormones in Growing Male Rats

Soybean is a rich source of isoflavones such as genistein and daidzein. Soy isoflavones have both weak estrogenic and anti-estrogenic effects and are structurally similar to tamoxifen, an agent that has an effect similar to that of estrogen in terms of reducing postmenopausal bone loss. The purpose of this study was to determine the effects of differences in protein source (casein vs soy) and isoflavone levels (reduced vs higher levels) on selected bone markers and hormones in growing male rats. Thirty weanling Sprague-Dawley young rats were divided into 3 groups: The control group was fed a casein-based diet, the soy concentrate group was fed soy protein with totally reduced isoflavones content (isoflavones 0.07 mg/g protein), and the soy isolate group was fed soy protein with a higher than normal isoflavones content (isoflavones 3.4 mg/g protein). The degree of bone formation was estimated by measuring serum osteocalcin and alkaline phosphoatase (ALP). By determining collagen cross-linkage by immunoassay and correcting with creatinine values, the bone resorption rate was compared. Serum osteocalcin, growth hormone, estrogen and calcitonin were analyzed using radio immunoassay kits. The bone formation marker and ALP activity were differentiated by protein source, showing higher values than casein in feeding either soy isolate or soy concentrate. In this study using growing rats, the differences in isoflavone contents were not a significant factor in either bone formation or bone reaborption markers. Moreover, the soy isolate group had significantly higher levels of growth hormone than the casein group. The findings of this study suggest that growth hormone is partially responsible for its bone-formation effects in young growing rats. Soy protein and the isoflavones in soy protein are beneficial for bone-formation in growing male rats. Therefore, exposure to soy protein and isoflavones early in life may have long-term health benefits in preventing bone diseases such as osteoporosis. Further study to evaluate the mechanism of action of isoflavones on bones is warranted.

Identification of Plasma Coagulation Factor XIII, Transglutaminase 3 and N epsilon-(gamma-glutamyl) lysine cross-Link in the Silicotic Nodule by Immunohistochemistry / 대한산업의학회지

OBJECTIVES: This study was performed to examine the immunohistochemical distribution of TGase 1, 2, 3, coagulation factor XIII and N epsilon-(gamma-glutamyl) lysine cross-link in the silicotic nodules formed after an intratracheal instillation of the silica. METHODS: The immunohistochemical examinations used antibodies against TGase 1, 2, 3, coagulation factor XIII and N epsilon-(gamma-glutamyl) lysine isopeptide in the silicotic nodules induced after an intratracheal instillation of 50 mg of size fractionated, crystalline silica. RESULTS: A high level of TGase 3 was related to the severity of fibrosis in silicotic nodules and extracellular coagulation factor XIII was detected around the nodules. Expressions of both membrane-bound TGase 1 and TGase 2 were barely detected in the nodules although high expressions were detected in the intact lung. Formation of N epsilon-(gamma-glutamyl) lysine cross-links was increased in severe fibrotic nodules. CONCLUSIONS: TGase 3 might contribute to the eventual stone-like fibrosis via formation of N epsilon-(gamma-glutamyl) lysine cross-links. Futhermore, coagulation factor XIII plays a role in the formation of a provisional matrix which results in fibrogenesis during silicotic nodule formation.

The cross-links between outer hair cell stereocilia in the guinea pig cochlea / 解放军医学杂志

Objective To investigate the structure and function of cross-links on stereocilia of guinea pig outer hair cell (OHC). Method The ultrastructures of cross-links on stereocilia of guinea pig OHC were observed by scanning electron microscopy and tannic acid procedures. Results The side-links ran horizontally between OHC stereocilia. The stereocilia of the same and different row on each hair cell were joined by horizontally-running links. The side-links were observed in the first turn as well as the fourth turn. There were more side-links on the intact stereocilia than that on the disrupted arrangement. The side-links in the first turn and the fourth turn were more abundant than that in the second turn and the third turn. The side-links between stereocilia were spare if the stereocilia were separated. The number of side-links on stereocilia was proportional to the number of bulb-like structures on stereocilia. Conclusion The side-link is a kind of morphological structure on hair cells stereocilia of cochlea. The results suggest that cross-links play an important role in maintaining the structure and function of the hair cell stereocilia.