In vitro retinoid binding and release from a collagen sponge material in a simulated intravaginal environment

Four in vitro preparations were constructed to simulate the intravaginal release of two retinoids, all-trans-retinoic acid (t-RA) and 13-cis-retinoic acid (c-RA), from a 0.7% collagen sponge diaphragm insert. Four t-RA concentrations, 0.019, 0.05, 0.1, and 0.15% in methanol were added to the sponge. The release into an artificial vaginal fluid was monitored serially over 72 h by serial analysis for t-RA and c-RA using high-pressure liquid chromatography. In each preparation, retinoid release was immediate and noncontinuous. At 37 degrees C, the retinoids were stable for at least 48 h. Trans-retinoic acid was the predominant retinoid recovered. Only trace amounts of the cis-isomer were released. Peak t-RA levels were 20 microM after 0.01%, 60-80 microM after 0.05%, 100-200 microM after 0.1%, and 320 microM after 0.15%. When the vaginal fluid bath was changed after 5 h, no further significant retinoid release occurred. There was significant loss of up to 70% of the applied t-RA into the collagen sponge. The retinoid binding was concentration dependent (higher binding with higher concentrations) and was maximal only after 24 h of co-incubation. The discontinuous release of t-RA and the high degree of binding to collagen would seem to preclude use of the diaphragm insert as a vaginal drug delivery system, at least for retinoids

A phase I trial of beta-all-trans-retinoic acid delivered via a collagen sponge and a cervical cap for mild or moderate intraepithelial cervical neoplasia.

A phase I trial was conducted of the vitamin A derivative beta-all-trans-retinoic acid (vitamin A acid; TRA), delivered via a collagen sponge and cervical cap for mild or moderate intraepithelial cervical neoplasia. On the basis of known skin and mucosal membrane toxicity, a concentration of 0.05% TRA in a cream-based vehicle was selected as the starting dose and was escalated later with the use of a modified Fibonacchi scale. The delivery device and the TRA were changed daily for 4 days, and side effects were assessed on days 1, 2, 3, 4, 8, and 30 by clinical and colposcopic examination. Vaginal, cervical, and systemic toxicity were evaluated in 35 patients. No dose-related systemic effects were found; mild cervical inflammation increased in many patients at higher doses. Unacceptably high vaginal toxicity was reached at a TRA concentration of 0.484%. A concentration of 0.372% TRA is recommended for use in phase II trials in mild and moderate cervical intraepithelial neoplasia

Bone Fracture Toughness and Strength Correlate With Collagen Cross‐Link Maturity in a Dose‐Controlled Lathyrism Mouse Model

Collagen cross‐linking is altered in many diseases of bone, and enzymatic collagen cross‐links are important to bone quality, as evidenced by losses of strength after lysyl oxidase inhibition (lathyrism). We hypothesized that cross‐links also contribute directly to bone fracture toughness. A mouse model of lathyrism using subcutaneous injection of up to 500 mg/kg β‐aminopropionitrile (BAPN) was developed and characterized (60 animals across 4 dosage groups). Three weeks of 150 or 350 mg/kg BAPN treatment in young, growing mice significantly reduced cortical bone fracture toughness, strength, and pyridinoline cross‐link content. Ratios reflecting relative cross‐link maturity were positive regressors of fracture toughness (HP/[DHLNL + HLNL] r2 = 0.208, p < 0.05; [HP + LP]/[DHNL + HLNL] r2 = 0.196, p < 0.1), whereas quantities of mature pyridinoline cross‐links were significant positive regressors of tissue strength (lysyl pyridinoline r2 = 0.159, p = 0.014; hydroxylysyl pyridinoline r2 = 0.112, p < 0.05). Immature and pyrrole cross‐links, which were not significantly reduced by BAPN, did not correlate with mechanical properties. The effect of BAPN treatment on mechanical properties was dose specific, with the greatest impact found at the intermediate (350 mg/kg) dose. Calcein labeling was used to define locations of new bone formation, allowing for the identification of regions of normally cross‐linked (preexisting) and BAPN‐treated (newly formed, cross‐link‐deficient) bone. Raman spectroscopy revealed spatial differences attributable to relative tissue age and effects of cross‐link inhibition. Newly deposited tissues had lower mineral/matrix, carbonate/phosphate, and Amide I cross‐link (matrix maturity) ratios compared with preexisting tissues. BAPN treatment did not affect mineral measures but significantly increased the cross‐link (matrix maturity) ratio compared with newly formed control tissue. Our study reveals that spatially localized effects of short‐term BAPN cross‐link inhibition can alter the whole‐bone collagen cross‐link profile to a measureable degree, and this cross‐link profile correlates with bone fracture toughness and strength. Thus, cross‐link profile perturbations associated with bone disease may provide insight into bone mechanical quality and fracture risk. © 2014 American Society for Bone and Mineral Research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110745/1/jbmr2356.pd

A randomized, controlled, prospective trial to evaluate the haemostatic effect of Lyostypt versus Surgicel in arterial bypass anastomosis: "COBBANA" trial

<p>Abstract</p> <p>Background</p> <p>The development of suture hole bleeding at peripheral arterial bypass anastomoses using PTFE graft prostheses is a common problem in peripheral vascular surgery. Traditionally the problem is managed by compression with surgical swabs and reversal heparin or by using several haemostatic device (e.g. different forms of collagen, oxidized cellulose, gelatine sponge, ethylcyanoacrylate glue or fibrin) with various success. Preclinical data suggest that the haemostatic effect of collagen is stronger than that of oxidized cellulose, but no direct clinical comparison of their hemostatic performance has been published so far.</p> <p>Design</p> <p>This randomized, controlled, prospective trial evaluates the haemostatic effect of Lyostypt versus Surgicel in arterial bypass anastomosis. 28 patients undergoing an elective peripheral vascular reconstruction due to peripheral vascular disease will be included. Suture hole bleeding occurring at the arterial bypass anastomosis using a PTFE prostheses will be stopped by the application of Lyostypt and/or Surgicel. The proximal anastomoses will be randomized intraoperatively. The patients will be allocated into 4 different treatment groups. Group1 Lyostypt distal/Surgicel proximal; Group 2: Lyostypt proximal/Surgicel distal; Group 3: Surgicel distal and proximal; Group 4: Lyostypt distal and proximal. Primary endpoint of the study is time to haemostasis. Secondary endpoints are the number of intraoperatively used haemostatic devices, postoperative mortality within 30 days as well as the intraoperative efficacy rating of the two devices evaluated by the surgeon. As a safety secondary parameter, the local and general complication occurring till 30 ± 10 days postoperatively will also be analysed. After hospital discharge the investigator will examine the enrolled patients again at 30 days after surgery.</p> <p>Discussion</p> <p>The COBBANA trial aims to assess, whether the haemostatic effect of Lyostypt is superior to Surgicel in suture hole bleedings of arterial bypass anastomoses.</p> <p>Trial registration</p> <p>NCT00837954</p

A computational procedure for functional characterization of potential marker genes from molecular data: Alzheimer's as a case study

Abstract Background A molecular characterization of Alzheimer's Disease (AD) is the key to the identification of altered gene sets that lead to AD progression. We rely on the assumption that candidate marker genes for a given disease belong to specific pathogenic pathways, and we aim at unveiling those pathways stable across tissues, treatments and measurement systems. In this context, we analyzed three heterogeneous datasets, two microarray gene expression sets and one protein abundance set, applying a recently proposed feature selection method based on regularization. Results For each dataset we identified a signature that was successively evaluated both from the computational and functional characterization viewpoints, estimating the classification error and retrieving the most relevant biological knowledge from different repositories. Each signature includes genes already known to be related to AD and genes that are likely to be involved in the pathogenesis or in the disease progression. The integrated analysis revealed a meaningful overlap at the functional level. Conclusions The identification of three gene signatures showing a relevant overlap of pathways and ontologies, increases the likelihood of finding potential marker genes for AD.</p