21,586 research outputs found

    Corneal alterations associated with pseudoexfoliation syndrome and glaucoma: A literature review

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    A systematic literature review was performed evaluating articles examining the effects of pseudoexfoliation syndrome (PEX) and glaucoma (PEXG) on the cornea with a focus on the corneal endothelium. We searched for articles relevant to pseudoexfoliation syndrome, pseudoexfoliation glaucoma and corneal endothelial cell counts using Pubmed, Google Scholar Database, Web of Science and cochrane Library databases published prior to September of 2016. We then screened the references of these retrieved papers and performed a Web of Science cited reference search. corneal characteristics analyzed included central corneal thickness (ccT), corneal nerve density, endothelial cell density (EcD), polymegathism, and pleomorphism. These parameters were compared in the following populations: control, PEX, PEXG, and primary open angle glaucoma (POAG). Over 30 observational studies were reviewed. Most studies showed a statistically significant lower EcD in PEX and PEXG populations compared to controls. Overall, PEX eyes had a non-statistically significant trend of lower EcDs compared to PEXG eyes. No consistent trends were found when analyzing differences in ccT amongst control, PEX and PEXG groups. For the few studies that looked at corneal nerve characteristics, the control groups were found to have statistically significantly greater nerve densities than PEX eyes, which had significantly greater densities than PEXG eyes. EcD and corneal nerve densities may be potential metrics for risk-stratifying patients with PEX and PEXG. Our literature review provided further evidence of the significant negative influence PEX has on the cornea, worsening as patients convert to PEXG

    A comparative study of peroxisomal structures in Hansenula polymorpha pex mutants

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    In a recent study, we performed a systematic genome analysis for the conservation of genes involved in peroxisome biogenesis (PEX genes) in various fungi. We have now performed a systematic study of the morphology of peroxisome remnants (‘ghosts’) in Hansenula polymorpha pex mutants (pex1–pex20) and the level of peroxins and matrix proteins in these strains. To this end, all available H. polymorpha pex strains were grown under identical cultivation conditions in glucose-limited chemostat cultures and analyzed in detail. The H. polymorpha pex mutants could be categorized into four distinct groups, namely pex mutants containing: (1) virtually normal peroxisomal structures (pex7, pex17, pex20); (2) small peroxisomal membrane structures with a distinct lumen (pex2, pex4, pex5, pex10, pex12, pex14); (3) multilayered membrane structures lacking apparent matrix protein content (pex1, pex6, pex8, pex13); and (4) no peroxisomal structures (pex3, pex19).

    The evaluation of correlation between Pseudoexfoliation of pupil and increased intraocular pressure or glaucoma in patients referred to ophthalmology clinic of Ardabil Alavi hospital

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    Introduction : Purpose : To evaluate the pseudoexfoliation syndrome and its associations with elevation of IOP/Glaucoma this study was designed and performed in Ardabil Alavi hospital. Methods : This was a hospital-based, cohort study in Ardabil Alavi hospital from Farvardin 1387 to Aban 1388. Only patients of aged 50 and older referred to Alavi clinic of ophthalmology were examined to find the PEX depositions. PEX was diagnosed on slit lamp biomicroscopy by the presence of white dandruff-like material in the pupillary margin or other sites of one or both eyes. These patients was known as “case group”, another group was prepared with the same age subgroups of case groups and was known as “control group”. There was 72 patients in both groups. All patients underwent a comprehensive ophthalmic evaluation. Visual acuity, refraction, Goldmann applanation tonometry, gonioscopy, slit lamp examination and dilated pupil fundus examination was performed. Results : Out of 144 eyes of case group, 112 (77.77%) had PEX depositions. There was a significant increase in number of PEX involved eyes with age. In this study the frequency of disease in men was higher than women (46 (63.9%) men, 26 (36.1%) women). Out of 72 patients, 40 (55.5%) patients were bilaterally and 32 (44.5%) patients were unilaterally involved. The mean of IOP in PEX involved eyes was 17.94±8.88 and 14.51±2.90 in non PEX involved eyes. The frequency of cortical cataract was higher than other forms. Conclusion : PEX is an important risk factor for increased IOP and glaucoma in our area and must be considered a lot. Patients with this risk factor must undergo frequent IOP measurement

    Poor recovery from cystic fibrosis pulmonary exacerbations is associated with poor long-term outcomes

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    RATIONALE: People with CF treated with IV antibiotics for a pulmonary exacerbation (PEx) frequently fail to recover to baseline FEV1 . The long-term impact of these events has not been studied. OBJECTIVES: To determine if a patient's spirometric recovery after a PEx is associated with time to next PEx within 1 year, the spirometric recovery after the next PEx, and/or the number of PEx episodes in the next 3 years. METHODS: We used data from the CF Foundation Patient Registry from 2004 to 2011. We randomly selected one PEx per patient that met inclusion/exclusion criteria. Patients were defined as Non-Responders if their best FEV1 (in liters) recorded in the 3 months after the PEx was <90% of the best FEV1 (in liters) in the 6 months before the PEx. We compared Responders and Non-Responders using multivariable regression models. RESULTS: We randomly chose 13 954 PEx episodes that met inclusion/exclusion criteria. A total of 2 762 (19.8%) patients were classified as Non-Responders. Non-Responders had a shorter median time to the next PEx, 235 (95%CI 218, 252) days, versus >365 days for Responders. Thirty-four percent of Non-Responders at the initial PEx were also Non-Reponders at the next PEx, versus 20% of Responders at the initial PEx. Non-Responders had more PEx episodes over the next 3 years, 4.99 (95%CI 4.84, 5.13), than Responders, 3.46 (95%CI 3.41, 3.51). CONCLUSIONS: Poor recovery after a PEx is associated with a shorter time to the next PEx, increased risk of poor recovery at a second PEx, and more frequent subsequent PEx treatments

    Poor recovery from a pulmonary exacerbation does not lead to accelerated FEV1 decline

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    BACKGROUND: Patients with CF treated for pulmonary exacerbations (PEx) may experience faster subsequent declines in FEV1. Additionally, incomplete recovery to baseline FEV1 occurs frequently following PEx treatment. Whether accelerated declines in FEV1 are preceded by poor PEx recovery has not been studied. METHODS: Using 2004 to 2011 CF Foundation Patient Registry data, we randomly selected one PEx among patients ≥6years of age with no organ transplantations, ≥12months of data before and after the PEx, and ≥1 FEV1 recorded within the 6months before and 3months after the PEx. We defined poor PEx recovery as the best FEV1 in the 3months after the PEx 5% predicted/year FEV1 decline and poor PEx recovery using multi-state Markov models. RESULTS: From 13,954 PEx, FEV1 declines of >5% predicted/year were more likely to precede poor spirometric recovery, HR 1.17 (1.08, 1.26), in Markov models adjusted for age and sex. Non-Responders were less likely to have a subsequent fast FEV1 decline, HR 0.41 (0.37, 0.46), than patients who recovered to >90% of baseline FEV1 following PEx treatment. CONCLUSIONS: Accelerated declines in FEV1 are more likely to precede a PEx with poor recovery than to occur in the following year. Preventing or halting declines in FEV1 may also have the benefit of preventing PEx episodes

    Short-term Organic Carbon Release and Chlorine Disinfectant Decay for Cross-linked Polyethylene (PEX) Plumbing Pipes

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    The use of cross-linked polyethylene (PEX) plumbing pipes has grown in popularity for residential applications. However, PEX pipes can leach organic materials into water that can enable biofilm growth, cause off-tastes and -odors, and may react with disinfectants to form disinfection by-products (DBP). Varied manufacturing processes that are applied to create PEX pipes add to the complexity of understanding organic materials released. In this study, organic carbon release from three PEX pipe brands was monitored for up to five days using a series of stagnation periods. Seven stagnation periods of 1, 2, 4, 8, 24, 72, and 120 hours were conducted at 50 degrees Celsius with varying initial chlorine concentrations for a type A (PEX-a), type B (PEX-b), and type C (PEX-c) brand. Pipes were exposed to chlorinated tap water synthesized in the lab. Water exposed to these pipes was analyzed to determine total organic carbon (TOC), assimilable organic carbon (AOC), total chlorine, and free chlorine concentrations. Results show that all pipe brands had different chlorine decay rates and TOC concentrations. Chlorine residual decayed the slowest and fastest for PEX-A pipes and PEX-C pipes, respectively. Chlorine completely decayed in most pipes by 24 hours when the initial chlorine concentration was 2.0 mg/L. PEX-B leached the most amount of contaminants, with a TOC concentration that far exceeded 2.0 mg/L within 24 hours. AOC concentrations tended to increase over time for all pipes. Future work should include additional brands, aged PEX pipes, different flow conditions, temperatures, and longer stagnation periods

    Comparative Genomics of Peroxisome Biogenesis Proteins:Making Sense of the PEX Proteins

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    PEX genes encode proteins involved in peroxisome biogenesis and proliferation. Using a comparative genomics approach, we clarify the evolutionary relationships between the 37 known PEX proteins in a representative set of eukaryotes, including all common model organisms, pathogenic unicellular eukaryotes and human. A large number of previously unknown PEX orthologs were identified. We analyzed all PEX proteins, their conservation and domain architecture and defined the core set of PEX proteins that is required to make a peroxisome. The molecular processes in peroxisome biogenesis in different organisms were put into context, showing that peroxisomes are not static organelles in eukaryotic evolution. Organisms that lack peroxisomes still contain a few PEX proteins, which probably play a role in alternative processes. Finally, the relationships between PEX proteins of two large families, the Pex11 and Pex23 families, were analyzed, thereby contributing to the understanding of their complicated and sometimes incorrect nomenclature. We provide an exhaustive overview of this important eukaryotic organelle
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