The effects on bacterial translocation and tissue damage of selenium treatment in an experimental intestina ischaemia-reperfusion model.

BACKGROUND: The free oxygen radicals formed with reperfusion following intestinal ischaemia are extremely toxic for the cells. Glutathione peroxidase, an important enzyme that prevents the formation of reactive oxygen species, requires selenium as a co-factor. This study aims to demonstrate the effects of selenium administration on reducing ischaemia-reperfusion damage. METHODS: In this study, 28 male Wistar rats were separated into four groups. To Groups 3 and 4, sodium selenite at the dose of 10 µg/kg/day was administered intraperitoneally for five days. In Groups 1 and 3, laparotomy was applied, and in Groups 2 and 4, following laparotomy, ischaemia was created by clamping the superior mesenteric artery for 45 mins, then reperfusion was provided for 90 mins. Blood, liver and ileum samples were taken from all the animals for examination of malondialdehyde. For examination of bacterial translocation, liver, spleen and mesenteric lymph node tissue samples were taken. A sample taken from the ileum was examined histopathologically. RESULTS: There was determined to be significantly more bacterial translocation in the mesenteric lymph nodes of the ischaemia-reperfusion group (p<0.05). In the histopathological evaluation, the score in the ischaemia-reperfusion group was significantly higher than the scores in the other groups (p<0.05). Elevated serum, liver and ileum malondialdehyde levels in the ischaemia-reperfusion group were significantly higher than those in the other groups (p<0.05). CONCLUSION: Selenium was seen to have decreased serum and tissue malondialdehyde levels and increased the histopathological damage developing in the intestines with ischaemia-reperfusion and thereby increased bacterial translocation.

Microscopic Characteristics of Late Intraocular Lens Opacifications.

CONTEXT.­: The increases in overall life expectancy and in lens surgeries performed on younger patients have resulted in a significant increase in the anticipated duration of artificial intraocular lenses (IOLs) in the eye. Thus, the physicochemical properties of the IOL become a critical issue, and several types of postoperative IOL opacifications have been reported. OBJECTIVE.­: To describe the microscopic characteristics of opacified IOLs. Glistenings and subsurface nanoglistenings are fluid-related phenomena developing mainly in hydrophobic acrylic IOLs and are associated with aqueous influx into the IOL matrix. Calcification presents in hydrophilic acrylic or silicone IOLs as deposits of hydroxyapatite or other phases of calcium. Snowflake degeneration is less common, and it manifests in older polymethyl methacrylate IOLs. DATA SOURCES.­: PubMed and ScienceDirect databases were searched for the following keywords: intraocular lens, IOL, cataract surgery, phacoemulsification, opacification, glistening, subsurface nanoglistenings, calcification, snowflake degeneration. English-language articles published up to October 15, 2019 were included in the study. The manuscript contains mainly a literature review; however, it was supplemented with original investigations from the David J. Apple International Laboratory for Ocular Pathology. CONCLUSIONS.­: Glistenings and subsurface nanoglistenings should be evaluated in a hydrated state and at room temperature; they manifest as microvacuoles sized from 1.0 to greater than 25.0 µm and less than 200 nm, respectively. Calcification deposits are situated on or underneath the surface of the IOL and can be stained with a 1% alizarin red solution or with the von Kossa method. Snowflake degeneration manifests as "particles" or "crystals," causing whitish IOL discoloration. Scanning electron microscopy or energy dispersive X-ray spectroscopy may improve the diagnostic accuracy.

Variation in intraocular lens calcification under different environmental conditions in eyes with supplementary sulcus-supported lenses.

PURPOSE: Analysis of explanted intraocular lenses (IOLs) from pseudophakic eyes with supplementary sulcus-supported IOLs. METHODS: In this laboratory investigation, ten supplementary and capsular bag IOLs were analyzed. All lenses were received between January 2012 and March 2018. Explants were examined morphologically with histological and electron microscopic techniques and patients' medical history was evaluated. Additionally, we used a technique new to this field: Transmission Electron Microscopy and electron diffraction pattern analysis was performed to investigate the structure of the opacifying crystals in detail. RESULTS: Eleven lenses were explanted due to IOL opacification from seven polypseudophakic eyes: In three cases the supplementary lens calcified, in three cases the capsular bag IOL (both lenses analyzed) and in one case both IOLs (only the supplementary was received). Additional surgical procedures and comorbidities included pars plana vitrectomy or Descemet stripping endothelial keratoplasty and diabetes mellitus. For each opacified lens, a varying layer of a Calcium phosphate beneath the optic surface was apparent. Crystal characterization revealed its composition to be Hydroxyapatite. CONCLUSIONS AND IMPORTANCE: We report on a series of secondary calcification in lenses explanted from polypseudophakic eyes. In some cases, calcification occurred in the capsular bag lens, in other cases in the supplementary lens, or in both. The severity of the morphological change could be related to the comorbidities and the presence of surgery subsequent to the lens implantations. Detailed morphology of the opacifying crystals was revealed.