A novel nonsense variant in TPM4 caused dominant macrothrombocytopenia, mild bleeding tendency and disrupted cytoskeleton remodeling

[Background]: Rare inherited thrombocytopenias are caused by alterations in genes involved in megakaryopoiesis, thrombopoiesis and/or platelet release. Diagnosis is challenging due to poor specificity of platelet laboratory assays, large numbers of culprit genes, and difficult assessment of the pathogenicity of novel variants. [Objectives]: To characterize the clinical and laboratory phenotype, and identifying the underlying molecular alteration, in a pedigree with thrombocytopenia of uncertain etiology. [Patients/Methods]: Index case was enrolled in our Spanish multicentric project of inherited platelet disorders due to lifelong thrombocytopenia and bleeding. Bleeding score was recorded by ISTH‐BAT. Laboratory phenotyping consisted of blood cells count, blood film, platelet aggregation and flow cytometric analysis. Genotyping was made by whole‐exome sequencing (WES). Cytoskeleton proteins were analyzed in resting/spreading platelets by immunofluorescence and immunoblotting. [Results]: Five family members displayed lifelong mild thrombocytopenia with a high number of enlarged platelets in blood film, and mild bleeding tendency. Patient's platelets showed normal aggregation and granule secretion response to several agonists. WES revealed a novel nonsense variant (c.322C>T; p.Gln108*) in TPM4 (NM_003290.3), the gene encoding for tropomyosin‐4 (TPM4). This variant led to impairment of platelet spreading capacity after stimulation with TRAP‐6 and CRP, delocalization of TPM4 in activated platelets, and significantly reduced TPM4 levels in platelet lysates. Moreover, the index case displayed up‐regulation of TPM2 and TPM3 mRNA levels. [Conclusions]: This study identifies a novel TPM4 nonsense variant segregating with macrothrombocytopenia and impaired platelet cytoskeletal remodeling and spreading. These findings support the relevant role of TPM4 in thrombopoiesis and further expand our knowledge of TPM4‐related thrombocytopenia.This work was partially supported by grants from Instituto de Salud Carlos III (ISCIII) and Feder (PI17/01966, PI20/00926), Gerencia Regional de Salud (GRS2061A/19, GRS2135/A/2020, GRS2314/A/2021), Fundación Mutua Madrileña (FMM, AP172142019) and Sociedad Española de Trombosis y Hemostasia (SETHFETH; Premio López Borrasca 2019 and Ayuda a Grupos de Trabajo en Patología Hemorrágica 2020 and 2021).Peer reviewe

Novel variants in GALE cause syndromic macrothrombocytopenia by disrupting glycosylation and thrombopoiesis

Glycosylation is recognized as a key process for proper megakaryopoiesis and platelet formation. The enzyme uridine diphosphate (UDP)-galactose-4-epimerase, encoded by GALE, is involved in galactose metabolism and protein glycosylation. Here, we studied 3 patients from 2 unrelated families who showed lifelong severe thrombocytopenia, bleeding diathesis, mental retardation, mitral valve prolapse, and jaundice. Whole-exome sequencing revealed 4 variants that affect GALE, 3 of those previously unreported (Pedigree A, p.Lys78ValfsX32 and p.Thr150Met; Pedigree B, p.Val128Met; and p.Leu223Pro). Platelet phenotype analysis showed giant and/or grey platelets, impaired platelet aggregation, and severely reduced alpha and dense granule secretion. Enzymatic activity of the UDP-galactose-4-epimerase enzyme was severely decreased in all patients. Immunoblotting of platelet lysates revealed reduced GALE protein levels, a significant decrease in N-acetyl-lactosamine (LacNAc), showing a hypoglycosylation pattern, reduced surface expression of gylcoprotein Ibα-IX-V (GPIbα-IX-V) complex and mature β1 integrin, and increased apoptosis. In vitro studies performed with patients-derived megakaryocytes showed normal ploidy and maturation but decreased proplatelet formation because of the impaired glycosylation of the GPIbα and β1 integrin, and reduced externalization to megakaryocyte and platelet membranes. Altered distribution of filamin A and actin and delocalization of the von Willebrand factor were also shown. Overall, this study expands our knowledge of GALE-related thrombocytopenia and emphasizes the critical role of GALE in the physiological glycosylation of key proteins involved in platelet production and function.This work was supported by grants from Instituto de Salud Carlos III (ISCIII) & Feder (PI17/01966, PI20/00926) and cofunded by European Union (ERDF/ESF, “Investing in your future”), Gerencia Regional de Salud (GRS2061/A/2019, GRS2135/A/2020, GRS2314/A/2021), Fundación Mutua Madrileña (FMM, AP172142019), Sociedad Española de Trombosis y Hemostasia (SETH-FETH; Premio López Borrasca 2019 and Ayuda a Grupos de Trabajo en Patología Hemorrágica 2020 and 2021), Fundación Castellano Leonesa de Hematología y Hemoterapia (FUCALHH 2020), Red Temática de Investigación Cooperativa en Cáncer (RTICC) (RD12/0036/0069), Centro de Investigación Biomédica en Red de Cáncer (CIBERONC CB16/12/00233). Progetti di ricerca di rilevante interesse Nazionale (PRIN 2017Z5LR5Z), and the European Commission (H2020-FETOPEN-1-2016-2017-SilkFusion ID 767309). The author´s research on Inherited Platelet Disorders is conducted in accordance with the aims of the multicentric project “Functional and Molecular Characterization of Patients with Inherited Platelet Disorders” of Grupo Español de Alteraciones Plaquetarias Congénitas (GEAPC). A.M.-Q. is fully supported by an “Ayuda predoctoral de la Junta de Castilla y León” by the Fondo Social Europeo (JCYL- EDU/556/2019 PhD scholarship) and received an “Ayuda para breves estancias formativas” from the Sociedad Española de Hematología y Hemoterapia (SEHH-FEHH), and from the Sociedad Española de Trombosis y Hemostasia (SETH-FETH); E.V. is fully supported by an “Ayuda para contratos predoctorales de la Universidad de Salamanca cofinanciadas por el banco Santander,” programa propio III convocatoria 2018; I.S.-G. is supported by a contract from the University of Salamanca cofinanced by the Junta de Castilla y León (Council of Education) and FEDER-European Union [ref. SA0118P20 (2)]; S.S.-M. and C.M.-G. received funding from the European Research Council (ERC) under the ERA-Per-Med programme (ERAPERMED2018-275) SYNtherapy and ISCIII (AC18/00093) cofunded by ERDF/ESF, “Investing in your future”; I.G.-T. and R.B. are supported by a grant from the Universidad de Salamanca (“Contrato postdoctoral Universidad de Salamanca programa propio II, 2019”)Peer reviewe

Corneal Edema after Cataract Surgery

his systematic review investigates the prevalence and underlying causes of corneal edemafollowing cataract surgery employing manual phacoemulsification. A comprehensive search encom-passing databases such as PubMed, Embase, ProQuest, Cochrane Library, and Scopus was conducted,focusing on variables encompassing cataract surgery and corneal edema. Two independent reviewerssystematically extracted pertinent data from 103 articles, consisting of 62 theoretical studies and41 clinical trials. These studies delved into various aspects related to corneal edema after cataractsurgery, including endothelial cell loss, pachymetry measurements, visual performance, surgicaltechniques, supplies, medications, and assessments of endothelial and epithelial barriers. This review,encompassing an extensive analysis of 3060 records, revealed significant correlations between cornealedema and endothelial cell loss during phacoemulsification surgery. Factors such as patient age,cataract grade, and mechanical stress were identified as contributors to endothelial cell loss. Fur-thermore, pachymetry and optical coherence tomography emerged as valuable diagnostic tools forassessing corneal edema. In conclusion, this systematic review underscores the link between cornealedema and endothelial cell loss in manual phacoemulsification cataract surgery. It highlights therelevance of factors like patient demographics and diagnostic modalities. However, further researchis essential to unravel the complexities of refractive changes and the underlying mechanisms.This study was supported by the following foundations: Alcon-FOM-UVEG Cathedra, Foundation of Ophthalmology Medicine, and Universitat de València.Medicin

Effect of the color of the intraocular lens on optical and visual quality

Purpose: To analyze the optical quality of intraocular lenses (IOL) with an orange (PC440Y) and a yellow (SN60AT) filter, and correlate these results with the visual quality of patients with these implants. Setting: Fisabio Oftalmologνa Mιdica, Valencia, Spain. Design: Randomized prospective study. Materials and Methods: The IOL optical quality was determined using the modulation transfer function (MTF) and the spectral transmission. The visual quality of 87 eyes with cataract (51 with orange filter and 36 with yellow filter) was determined by best corrected visual acuity (BCVA) and contrast sensitivity function (CSF) under photopic and mesopic conditions. To analyze the results, we use a Student′s t-test. Results: Orange lens filtered more of the blue spectrum (cut-off wavelength of 370 nm) than the yellow lens (390 nm). The MTF of the yellow lens was better than the orange lens (average modulation of 0.676 for natural and 0.672 for orange). The patients′ BCVA was 0.02 + 0.10 logMAR for both lenses. The CSF obtained with the yellow lens was slightly better, although without statistically significant differences (P > 0.05). Conclusions: Both lenses are of good optical quality. The patients′ visual quality was similar with both lenses, and optical quality was also similar. The color of the lens does not affect the visual quality of the patient

A rapid method for measuring intraocular lens power in vitro with a focimeter

En este artículo se describe un nuevo método para medir la potencia de la lente intraocular usando un focímetro, una lente oftálmica negativa y una solución salina. Para probar su fiabilidad, se mide la potencia de 58 lentes diferentes y se comparan con la potencia indicada por el fabricante. A pesar de las limitaciones des dispositivo experimental ideado, los resultados muestran una buena correlación entre ambos parámetros

Grupo Colaborativo de Resistencia Bacteriana, Chile: recommendations 2014 towards the control of bacteria resistance

Artículo de publicación ISIEn la reunión anual del Grupo Colaborativo de Resistencia Bacteriana del año 2014 se revisaron en profundidad cinco tópicos cuyos antecedentes y conclusiones se detallan en este documento. Los temas fueron: I.- Novedades del CLSI 2014: se revisaron las dificultades e implicancias de su implementación a nivel local y se establecen recomendaciones. II.- Criterios para la determinación de incidencia de microoganismos multi-resistentes en unidades de pacientes críticos, donde se definieron los indicadores y la metodología de vigilancia para una mejor cuantificación del problema. III.- Se establecieron requisitos de calidad a considerar por los profesionales que participan en la selección de antimicrobianos en el hospital. IV.- Se discutieron las políticas de traslado, tamizaje y precauciones de contacto para el control de la transmisión de bacterias multiresistentes. V.- Se establecieron recomendaciones para los establecimientos de salud frente a la pesquisa de una enterobacteria productora de carbapenemasa en formato de lista de chequeo para la implementación rápida en hospitales sin endemia de estos agentes. Estas sugerencias nacen del trabajo conjunto de especialistas de muchos hospitales, no representan un consenso o normativa pero pueden ser de ayuda para el control de la resistencia en cada establecimiento de salud del país