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    Novel genome-wide associations for age-related macular degeneration in the sarcoglycan-sarcospan protein complex
    (2020)
    Asaf Calderon, Andrea Michelle
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    Dewan, Andrew
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    Ramírez, Israel
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    Zepeda-Palacio, Claudia
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    Palacio, Claudia
    Purpose : Since the advent of genomic approaches, many chromosomal regions and polymorphisms have been associated with age-related macular degeneration (AMD). However, most of the disease variability might not be still captured by current researched genetic markers due to power issues. We have evidence that at least one component of the sarcoglycan-sarcospan protein complex (Sg-Sspn) gene is associated with increased odds of geographic atrophy (GA) AMD. Moreover, the retina of the knocked-out mouse model for the Sg-Sspn phenotypically resembles GA. Here, we aimed to explore the genome-wide association of the Sg-Sspn complex gene regions with AMD.
      19  2
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    Altered calcium pump and secondary deficiency of γ-sarcoglycan and microspan in sarcoplasmic reticulum membranes isolated from δ-sarcoglycan knockout mice
    (2010)
    Solares-Pérez, Alhondra
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    Álvarez, Rocío
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    Crosbie, Rachelle H.
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    Vega-Moreno, Jesús
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    Medina-Monares, Joel
    Sarcoglycans (SGs) and sarcospan (SSPN) are transmembrane proteins of the dystrophin-glycoprotein complex. Mutations in the genes encoding SGs cause many inherited forms of muscular dystrophy. In this study, using purified membranes of wild-type (WT) and δ-SG knockout (KO) mice, we found the specific localization of the SG-SSPN isoforms in transverse tubules (TT) and sarcoplasmic reticulum (SR) membranes. Immunoblotting revealed that the absence of δ-SG isoforms in TT and SR results in a secondary deficiency of γ-SG and μSPN. Our results showed augmented ATP hydrolytic activity, ATP-dependent calcium uptake and passive calcium efflux, probably through SERCA1 in KO compared to WT mice. Furthermore, we found a conformational change in SERCA1 isolated from KO muscle as demonstrated by calorimetric analysis. Following these alterations with mechanical properties, we found an increase in force in KO muscle with the same rate of fatigue but with a decreased fatigue recovery compared to WT. Together our observations suggest, for the first time, that the δ-SG isoforms may stabilize the expression of γ-SG and μSPN in the TT and SR membranes and that this possible complex may play a role in the maintenance of a stable level of resting cytosolic calcium concentration in skeletal muscle.
    Scopus© Citations 11  11  1
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    A new de novo mutation in a non-hot spot region at the DMD gene in a Mexican family
    (2015)
    Luna-Angulo, A. B.
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    Gómez-Díaz, B.
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    Escobar-Cedillo, R. E.
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    Anaya-Segura, M. A.
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    In this report we present the analysis of a sporadic case of DMD and his family. In the present case, a deletion of exons 18-47 is presented which predicts abolition of the reading frame and is located between the well-known deletion hot spots of the DMD gene. This mutation was not previously reported in the Leiden database (LOVD). Both MLPA and segregation analysis with short tandem repeat markers elucidated the status of the mother, sister and the younger brother of the proband, who were not carriers of the mutation. This case provides a description of a new pathogenic variant presented as de novo mutation in a DMD patient. Haplotype analysis and complete gene screening may improve genetic counseling in cases of germline mosaicism and de novo mutations.
      6  1
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    Brief inflammatory profile after femtosecond laser-assisted pretreatment in nuclear cataract surgery
    (2020)
    Palacio, Claudia
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    Antonio-Aguirre, Bani
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    Mendoza Velásquez, Cristina
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    Camacho-Ordóñez, Azyadeh
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    Purpose : Femtosecond laser-assisted cataract surgery (FLACS) is an FDA-approved treatment with increasing popularity. So far, there are no studies assessing the inflammatory response to FLACS corneal incision, anterior capsulorhexis, and nuclear fragmentation before phacoemulsification in patients exclusively diagnosed with nuclear cataracts. Here, we measured key inflammatory markers in the aqueous humor of patients exposed to femtosecond laser pretreatment. Methods : We performed a cross-sectional study of 67 patients diagnosed with nuclear cataract (LOCS III NO3) undergoing surgery. Of those, 34 were exposed to femtosecond laser pretreatment. At the beginning of the surgery, we collected aqueous humor samples under sterile conditions through a side-port incision. Samples were collected 8 minutes after laser treatment. We measured PgE2 by competitive ELISA, IL-1 β, and IL-6 through cytometric bead arrays. We performed bivariate and stratified analysis in SAS v.9.4. ©Investigative Ophthalmology & Visual Science
      33  1
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    Lack of Delta-Sarcoglycan (Sgcd) Results in Retinal Degeneration
    (2019)
    Peralta-Ildefonso, Martha Janneth
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    Ramírez-Sánchez, Israel
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    ;
    Age-related macular degeneration (AMD) is the leading cause of central vision loss and severe blindness among the elderly population. Recently, we reported on the association of the SGCD gene (encoding for δ-sarcoglycan) polymorphisms with AMD. However, the functional consequence of Sgcd alterations in retinal degeneration is not known. Herein, we characterized changes in the retina of the Sgcd knocked-out mouse (KO, Sgcd−/−). At baseline, we analyzed the retina structure of three-month-old wild-type (WT, Sgcd+/+) and Sgcd−/− mice by hematoxylin and eosin (H&E) staining, assessed the Sgcd-protein complex (α-, β-, γ-, and ε-sarcoglycan, and sarcospan) by immunofluorescence (IF) and Western blot (WB), and performed electroretinography. Compared to the WT, Sgcd−/− mice are five times more likely to have retinal ruptures. Additionally, all the retinal layers are significantly thinner, more so in the inner plexiform layer (IPL). In addition, the number of nuclei in the KO versus the WT is ever so slightly increased. WT mice express Sgcd-protein partners in specific retinal layers, and as expected, KO mice have decreased or no protein expression, with a significant increase in the α subunit. At three months of age, there were no significant differences in the scotopic electroretinographic responses, regarding both a- and b-waves. According to our data, Sgcd−/− has a phenotype that is compatible with retinal degeneration. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
    Scopus© Citations 5  30  2
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    Pharmacological Treatments and Therapeutic Targets in Muscle Dystrophies Generated by Alterations in Dystrophin-Associated Proteins
    (2024)
    Alexandra Luna-Angulo
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    Carlos Landa-Solís
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    Rosa Elena Escobar-Cedillo
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    Laura Sánchez-Chapul
    <jats:p>Muscular dystrophies (MDs) are a heterogeneous group of diseases of genetic origin characterized by progressive skeletal muscle degeneration and weakness. There are several types of MDs, varying in terms of age of onset, severity, and pattern of the affected muscles. However, all of them worsen over time, and many patients will eventually lose their ability to walk. In addition to skeletal muscle effects, patients with MDs may present cardiac and respiratory disorders, generating complications that could lead to death. Interdisciplinary management is required to improve the surveillance and quality of life of patients with an MD. At present, pharmacological therapy is only available for Duchene muscular dystrophy (DMD)—the most common type of MD—and is mainly based on the use of corticosteroids. Other MDs caused by alterations in dystrophin-associated proteins (DAPs) are less frequent but represent an important group within these diseases. Pharmacological alternatives with clinical potential in patients with MDs and other proteins associated with dystrophin have been scarcely explored. This review focuses on drugs and molecules that have shown beneficial effects, mainly in experimental models involving alterations in DAPs. The mechanisms associated with the effects leading to promising results regarding the recovery or maintenance of muscle strength and reduction in fibrosis in the less-common MDs (i.e., with respect to DMD) are explored, and other therapeutic targets that could contribute to maintaining the homeostasis of muscle fibers, involving different pathways, such as calcium regulation, hypertrophy, and maintenance of satellite cell function, are also examined. It is possible that some of the drugs explored here could be used to affordably improve the muscular function of patients until a definitive treatment for MDs is developed.</jats:p>
      4
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    Detección de una mutación en el gen KCNQ1 (KvLQT1) causante de síndrome de Jervell, Lange-Nielsen en una familia mexicana
    (2006-07)
    Márquez, Manlio F.
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    Hernández-Pacheco, Guadalupe
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    Fabregat, Juan R.
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    Pérez-Vielma, Nadia
    Antecedentes: Los síndromes de QT largo son enfermedades hereditarias causadas por mutaciones en los genes que codifican las proteínas de los canales iónicos transmembranales de sodio o potasio. Se han encontrado más de 200 mutaciones en por lo menos seis genes. El síndrome de Jervell y Lange-Nielsen (JLN) es la variedad recesiva de la enfermedad y se asocia con sordera congénita. Estudios recientes sugieren correlaciones fenotipo-genotipo con implicaciones importantes para el diagnóstico y tratamiento de este padecimiento. Métodos: En el presente trabajo se analizó el gen KCNQ1 (KvLQTl) en una familia mexicana afectada por síndrome de JLN, utilizando el método de secuenciación automática. © Archivos de Cardiología de México
    Scopus© Citations 7  13  2
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    Machine learning method to establish the connection between age related macular degeneration and some genetic variations
    Medicine research based in machine learning methods allows the improvement of diagnosis in complex diseases. Age related Macular Degeneration (AMD) is one of them. AMD is the leading cause of blindness in the world. It causes the 8.7% of blind people. A set of case and controls study could be developed by machine-learning methods to find the relation between Single Nucleotide Polymorphisms (SNPs) SNP_A, SNP_B, SNP_C and AMD. In this paper we present a machine-learning based analysis to determine the relation of three single nucleotide SNPs and the AMD disease. The SNPs SNP_B, SNP_C remained in the top four relevant features with ophthalmologic surgeries and bilateral cataract. We aim also to determine the best set of features for the classification process. © Springer International Publishing AG 2016.
    Scopus© Citations 1  56  2
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    FMR1 CGG repeat distribution and linked microsatellite-SNP haplotypes in normal Mexican Mestizo and indigenous populations
    (2006)
    Felix-López, Xóchitl Adriana
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    Argüello-García, Raúl
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    Cerda-Flores, Ricardo M.
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    Peñaloza-Espinoza, Rosenda I.
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    Buentello-Malo, Leonor
    The (CGG)n repeat size distribution in the FMR1 gene was studied in healthy individuals: 80 X chromosomes of Mexican Mestizos from Mexico City and 33 X chromosomes of Mexican Amerindians from three indigenous communities (Purepechas, Nahuas, and Tzeltales), along with alleles and haplotypes defined by two microsatellite polymorphic markers (DXS548 and FRAXAC1) and two single nucleotide polymorphisms (FMRA and FMRB). Genetic frequencies of Mestizo and Amerindian subpopulations were statistically similar in almost all cases and thus were considered one population for comparisons with other populations. Sixteen (CGG)n alleles in the 17–38 size range were observed, and the most common were the 25 (38.0%), 26 (28.3%), and 24 (12.3%) repeat alleles. This pattern differs from most other populations reported, but a closer relation to Amerindian, European, and African populations was found, as expected from the historical admixture that gave rise to Mexican Mestizos. The results of the CA repeats analysis at DXS548-FRAXAC1 were restricted to nine haplotypes, of which haplotypes 7-4 (52.2%), 8-4 (23.8%), and 7-3 (11.5%) were predominant. The modal haplotype 7-4, instead of the nearly universal haplotype 7-3, had been reported exclusively in Eastern Asian populations. Likewise, only seven different FRAXAC1-FMRA-FMRB haplotypes were observed, including five novel haplotypes (3TA, 4TA, 3-A, 4A, and 5A), compared with Caucasians. Of these, haplotypes -A (78.7%) and 3-A (13.2%) were the most common in the Mexican population. These data suggest a singular but relatively low genetic diversity at FMR1 in the studied Mexican populations that may be related to the recent origin of Mestizos and the low admixture rate of Amerindians.
      13  2