Comparison of penetrating and endothelial keratoplasty in patients with iridocorneal endothelial syndrome: A registry study.

BACKGROUND: To compare graft survival of endothelial keratoplasty (EK) versus penetrating keratoplasty (PK) in patients with iridocorneal endothelial (ICE) syndrome and identify ocular features associated with graft survival. METHODS: Observational, prospective, cohort study. A total of 30 806 first grafts performed between 1985 and 2020 were identified through the Australian Corneal Graft Registry and included in this observational, prospective cohort study. A total of 196 eyes underwent a primary corneal graft for ICE syndrome. Kaplan-Meier graft survival plots and Chi-squared tests were performed to identify graft survival rates for EK and PK. A history of raised intraocular pressure (IOP) was also recorded and analysed. Graft survival of eyes with ICE syndrome were compared to that of other indications. RESULTS: Grafts performed for ICE syndrome increased to 0.8% of all cases during the 2005 to 2020 period compared with 0.5% between 1985 to 2004 (χ2 =9.35, p = 0.002). From 2010, EK surpassed PK as the preferred graft type. Survival of primary grafts in eyes with ICE syndrome was lower than for other indications (log-rank = 56.62, p < 0.001). Graft survival was higher following PK than Descemet stripping (automated) endothelial keratoplasty (DS(A)EK) (log-rank = 10.56, p = 0.001). Graft survival was higher in eyes without a history of raised IOP compared to those with a reported history of raised IOP (log-rank = 13.06, p < 0.001). CONCLUSIONS: ICE syndrome carries a poor prognosis for graft survival. DS(A)EK had a poorer prognosis than PK. A history of raised IOP is associated with higher risk of graft failure.

Further development of silk sericin as a biomaterial: comparative investigation of the procedures for its isolation from Bombyx mori silk cocoons.

There is significant research dedicated to fibroin and sericin, the two major proteinaceous components of the silk threads produced by the domesticated silkworm, Bombyx mori. While fibroin is accepted as an established biomaterial, sericin (BMSS) has been largely neglected in this respect on the account of a hypothetical allergenic activity. Research over the past decade, including our previous study (Prog Biomater 2:14, 2013), demonstrated the biocompatibility of sericin and feasibility of its use as a biomaterial. However, the current procedures for isolating BMSS from the raw silk cocoons can only provide degraded proteins, where the size and distribution of their molecular masses are significantly altered. Based on the plausible assumption that such effects can have a negative impact on the properties of sericin as a biomaterial, in this study we investigated comparatively four different extraction procedures in order to find the method that would cause the least hydrothermal degradation of BMSS. The products resulting from commonly used procedures (extraction in boiling water, alkaline extraction, and extraction in autoclave) were compared to those resulting from aqueous extraction in mild conditions as described a long time ago by Anderlini. The molecular mass distribution in BMSS resulting from each procedure was examined by electrophoretic analysis performed on sodium dodecyl sulphate-polyacrylamide gel (SDS-PAGE), while the conformational changes pertaining to secondary structure of BMSS were evaluated by Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectrometry. The electrophoretograms indicated that the aqueous extraction in mild conditions conducted at 50 °C for durations up to 4 weeks, with/without stirring, afforded the least degraded BMSS. The infrared spectrometric analysis showed that BMSS resulting from the mild extraction method contained predominantly ß-sheet conformations, while the more degradative methods (alkaline, autoclave) led to BMSS where the random-coil conformations were preferential. The long-duration aqueous extraction at 50 °C (but not at 60 °C) appeared as a valid option for obtaining BMSS products where the hydrothermally induced fragmentation of the polypeptidic components is minimized.

The role of endocannabinoids in pregnancy.

Endocannabinoids are a family of lipid signalling molecules. As with prostaglandins (PGs), endocannabinoids are derived from polyunsaturated fatty acids and affect cell function via receptor-mediated mechanisms. They also bind to PG receptors, although at a lower affinity. The endocannabinoid network is regulated in pregnancy from embryo development to labour onset. Even small changes in endocannabinoid exposure can retard embryo development and affect implantation success. There is now compelling evidence that aberrant expression of factors involved in the endocannabinoid pathway in the placenta and circulating lymphocytes results in spontaneous miscarriage and poor pregnancy outcomes. It is likely that competition between endocannabinoids, PGs and other similar lipids ultimately determines how phospholipid/fatty acid substrates are metabolised and, thus, the balance between the uterotonic and tocolytic activities. We, therefore, hypothesise that endocannabinoid profiles may be used as a biomarker to predict and/or identify spontaneous labour onset.