Structural alterations of the erythrocyte membrane proteins in diabetic retinopathy

Background: Several rheological disorders of the erythrocytes, such as increased aggregation and decreased deformability, have been observed in diabetes mellitus and have been implicated in the development of diabetic microangiopathy. Structural alterations of the erythrocyte membrane proteins caused by the diabetic process may be at the origin of those observations. In the present study, we searched for erythrocyte membrane protein alterations in diabetic retinopathy. Methods: We examined peripheral blood samples from 40 type-2 diabetic patients with diabetic retinopathy of variable severity (19 males and 21 females, mean age 66.8years, Group A) and we compared them with samples from 19 type-2 diabetic patients without diabetic retinopathy (13 males and six females, mean age 66.5years, Group B) and 16 healthy volunteers (eight males and eight females, mean age 65.6years, Group C). Erythrocyte membrane ghosts from all samples were subjected to SDS-PAGE, and the electrophoretic pattern of transmembrane and cytoskeletal proteins was analysed for each sample. The protein quantification of each electrophoretic band was accomplished through scanning densitometry. Results: No significant deviations from normal electrophoresis were observed in Groups B and C, apart from an increase in band 8 in two samples from Group B (11%). In contrast, in 14 samples from Group A (35%) we detected increases in protein band 8 and/or membrane-bound haemoglobin along with a decrease in spectrin. Moreover, increased mobility of band 3, an aberrant high molecular weight (MW) (>255kDa) band and a low MW (42kDa) band were evident in ten samples from Group A (25%). Glycophorins were altered in 46% of Group-A patients versus 38% of Group-B patients. Females and patients with long duration of diabetes presented more electrophoretic abnormalities. Conclusions: Structural alterations of the erythrocyte membrane proteins are shown for the first time in association with diabetic retinopathy. Their detection may serve as a blood marker for the development of diabetic microangiopathy. Further studies are needed to assess whether pharmaceutical intervention to the rheology of erythrocytes can prevent or alleviate microvascular diabetic complication

Impact of flight and equivalent short-term high-altitude exposure on ocular structures and function

Background: Exposure to high-altitude conditions during flight or similar activities affects many aspects of visual function, which is critical not only for flight safety but for any altitude-related activity. We aimed to summarize the available literature pertaining to ocular changes during flight or equivalent short-term high-altitude exposure (e.g., hypobaric chamber, effortless ascent lasting less than or equal to 24 h) and to highlight future research priorities. Methods: Using the PubMed/MEDLINE and Web of Science/ISI Web of Knowledge databases with structured search syntax, we conducted a systematic review of the literature spanning a 40-year period (January 1, 1983, to October 10, 2023). Articles pertaining to ocular changes during flight or flight-equivalent exposure to altitude were retrieved. The reference lists of retrieved studies were also searched, and citations of these references were included in the results. Results: Of 875 relevant PubMed and ISI publications, 122 qualified for inclusion and 20 more were retrieved from the reference lists of initially selected records, for a total of 142 articles. Reported anterior segment changes included deterioration in tear film stability and increased dry eye incidence, increased corneal thickness, discomfort and bubble formation in contact lens users, refraction changes in individuals with prior refractive surgery, decreased intraocular pressure, and alterations in pupillary reaction, contrast sensitivity, and visual fields. Photoreceptor–visual pathway changes included alterations in both photoreceptors and neuro-transduction, as evidenced in dark adaptation, macular recovery time, reduction in visual field sensitivity, and optic neuritis (likely an element of decompression sickness). Retinochoroidal changes included increases in retinal vessel caliber, retinal blood flow, and choroidal thickness; central serous chorioretinopathy; and retinal vascular events (non-arteritic ischemic optic neuropathy, high-altitude retinopathy, and retinal vein occlusion). Conclusions: The effect of short-term high-altitude exposure on the eye is, in itself, a difficult area to study. Although serious impairment of visual acuity appears to be rare, ocular changes, including tear film stability, contact lens wear, central corneal thickness, intraocular pressure, contrast sensitivity, stability of refractive surgeries, retinal vessels, visual fields, and macula recovery time, should be considered in civilian aviators. Our report provides guidance to climbers and lowlanders traveling to altitude if they have pre-existing ocular conditions or if they experience visual symptoms while at altitude. However, key outcomes have been contradictory and comprehensive studies are scarce, especially those pertaining to the choroid and retina. Such studies could not only deepen our understanding of high-altitude ocular pathophysiology, but could also offer valuable information and treatment possibilities for a constellation of other vision-threatening diseases

Delirium in Older Patients With COVID-19 Presenting to the Emergency Department

Importance: Delirium is common among older emergency department (ED) patients, is associated with high morbidity and mortality, and frequently goes unrecognized. Anecdotal evidence has described atypical presentations of coronavirus disease 2019 (COVID-19) in older adults; however, the frequency of and outcomes associated with delirium in older ED patients with COVID-19 infection have not been well described. Objective: To determine how frequently older adults with COVID-19 present to the ED with delirium and their associated hospital outcomes. Design, Setting, and Participants: This multicenter cohort study was conducted at 7 sites in the US. Participants included consecutive older adults with COVID-19 presenting to the ED on or after March 13, 2020. Exposure: COVID-19 was diagnosed by positive nasal swab for severe acute respiratory syndrome coronavirus 2 (99% of cases) or classic radiological findings (1% of cases). Main Outcomes and Measures: The primary outcome was delirium as identified from the medical record according to a validated record review approach. Results: A total of 817 older patients with COVID-19 were included, of whom 386 (47%) were male, 493 (62%) were White, 215 (27%) were Black, and 54 (7%) were Hispanic or Latinx. The mean (SD) age of patients was 77.7 (8.2) years. Of included patients, 226 (28%) had delirium at presentation, and delirium was the sixth most common of all presenting symptoms and signs. Among the patients with delirium, 37 (16%) had delirium as a primary symptom and 84 (37%) had no typical COVID-19 symptoms or signs, such as fever or shortness of breath. Factors associated with delirium were age older than 75 years (adjusted relative risk [aRR], 1.51; 95% CI, 1.17-1.95), living in a nursing home or assisted living (aRR, 1.23; 95% CI, 0.98-1.55), prior use of psychoactive medication (aRR, 1.42; 95% CI, 1.11-1.81), vision impairment (aRR, 1.98; 95% CI, 1.54-2.54), hearing impairment (aRR, 1.10; 95% CI 0.78-1.55), stroke (aRR, 1.47; 95% CI, 1.15-1.88), and Parkinson disease (aRR, 1.88; 95% CI, 1.30-2.58). Delirium was associated with intensive care unit stay (aRR, 1.67; 95% CI, 1.30-2.15) and death (aRR, 1.24; 95% CI, 1.00-1.55). Conclusions and Relevance: In this cohort study of 817 older adults with COVID-19 presenting to US emergency departments, delirium was common and often was seen without other typical symptoms or signs. In addition, delirium was associated with poor hospital outcomes and death. These findings suggest the clinical importance of including delirium on checklists of presenting signs and symptoms of COVID-19 that guide screening, testing, and evaluation

Examining Mobile Search and Re-finding Behaviour

Mobile search has been a target of research for many years as it is challenging, multi-level and rapidly increasing in use, much like the mobile platforms themselves. This work examines the aforementioned subject from two of its aspects; mobile re-finding behaviour and queries' contextual information. Re-finding behaviour is an well-known phenomenon amongst the big search engines. It describes the tendency people have to search for contents of a web page they have already viewed before. This also applies to internet access through mobile environment. Studies have shown that identifying and exploiting this phenomenon can lead to improving the availability of information while reducing the cost of access. However, according to previous work, the phenomenon is declining and with the work of this thesis, we inspect its current state. In parallel with that, we examine mobile search semantics in the context of topic, time and location. Analysis on this contextual information helps us better understand users' online behaviour. For the purposes of the project, an Android Logging Framework was developed which was used to perform a live user study with 14 smartphone users, for the duration of a month. Results showed a 5,52% of average re-finding behaviour amongst the participants, while revealing patterns concerning their search queries. Topic of the searches is influenced by the time of the day, as well as the location of the users. Finally, a high number of searches have migrated from the browser to a richer and more intuitive environment, that of topic-specific applications.Web Information SystemsSoftware TechnologyElectrical Engineering, Mathematics and Computer Scienc

Biological Mineralization of Hydrophilic Intraocular Lenses

Biomaterials calcify upon implantation in contact with biological fluids, which are supersaturated with respect to more than one crystalline phase of calcium phosphate. The implantation of intraocular lenses (IOLs) for cataract treatment has been hailed as a major advance. Hydrophilic acrylic IOLs, made of Poly(2-hydroxyethyl methacrylate) (PHEMA), upon contact with aqueous humor, exhibit significant incidence of opacification, due to the formation of calcium phosphate crystals, mainly hydroxyapatite (Ca5(PO4)3OH, HAP) on the surface or in their interior. The aqueous humor is supersaturated with respect to HAP. Clinical findings were duplicated by laboratory experiments through the development of appropriate experimental models which included batch reactors, well stirred operating at constant supersaturation (CCR) and reactors simulating anterior eye chamber (ECSR). In both CCR and ECSR, simulated aqueous humor was used. In ECSR the flow rate was the same as in the eye chamber (2.5 mL per 24 h). HAP formed both on the surface and inside the IOLs tested. Induction times preceding the crystallization of HAP on the surface of the IOLs and crystal growth rates were measured. Surface hydroxyl ionized groups favored the development of locally high supersaturation by surface complexation. In the interior of the IOLs, HAP formed by the diffusion of the calcium and phosphate ions inside the polymeric matrix

Lysyl oxidase-like 1 polymorphisms in a southwestern Greek cataract population with pseudoexfoliation syndrome

Alexios A Panoutsopoulos,1 Vassiliki S Gartaganis,2 Marios P Giannakopoulos,1 Panos D Goumas,3 Evangelos D Anastassiou,4 Sotirios P Gartaganis1 1Department of Ophthalmology, School of Medicine, University of Patras, Achaia, Greece; 2Protein Chemistry Group, Institute of Molecular Oncology, BSRC “Al Fleming”, Vari, Greece; 3Department of Otolaryngology, Head and Neck Surgery, 4Department of Microbiology, School of Medicine, University of Patras, Achaia, Greece Purpose: The aim of this study was to determine the possible association of rs1048661 and rs3825942 single nucleotide polymorphisms (SNPs) in the lysyl oxidase-like 1 (LOXL1) gene of cataract patients from southwestern Greece with pseudoexfoliation (PEX) syndrome. Patients and methods: Ninety-three patients with PEX syndrome and 74 without PEX syndrome were recruited with the principal diagnosis being cataract. LOXL1 SNPs, rs1048661 and rs3825942, were genotyped by using polymerase chain reaction. Results: The G allele of rs1048661 was found in 96.7% in the PEX group as compared to 80.5% of non-PEX alleles (P=19×10-4; Odds ratio [OR] =5.37; 95% confidence interval [CI] =1.68–17.12). Similarly, the G allele of rs3825942 was found in 72.1% of the PEX group as compared to 41.8% of non-PEX alleles (P=4×10-5; OR =3.78; 95% CI =1.98–7.23). The T and A allele frequencies of rs1048661 and rs3825942, respectively, were underrepresented in the PEX group patients as compared to non-PEX group. Conclusion: Our data confirm previously reported association between LOXL1 polymorphisms and PEX syndrome in a southwestern Greek population. A significant association was found for the G allele of rs1048661 and rs3825942 demonstrating that the GG haplotype is a high-risk factor for the development of PEX syndrome. Keywords: exfoliative syndrome, PEX syndrome, single nucleotide polymorphism