10 results on '"Meza RA"'
Search Results
2. Rapid prototyping of a polymer MEMS droplet dispenser by laser-assisted 3D printing.
- Author
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Courson R, Bratash O, Maziz A, Desmet C, Meza RA, Leroy L, Engel E, Buhot A, Malaquin L, and Leïchlé T
- Abstract
In this work, we introduce a polymer version of a previously developed silicon MEMS drop deposition tool for surface functionalization that consists of a microcantilever integrating an open fluidic channel and a reservoir. The device is fabricated by laser stereolithography, which offers the advantages of low-cost and fast prototyping. Additionally, thanks to the ability to process multiple materials, a magnetic base is incorporated into the cantilever for convenient handling and attachment to the holder of a robotized stage used for spotting. Droplets with diameters ranging from ∼50 µm to ∼300 µm are printed upon direct contact of the cantilever tip with the surface to pattern. Liquid loading is achieved by fully immersing the cantilever into a reservoir drop, where a single load results in the deposition of more than 200 droplets. The influences of the size and shape of the cantilever tip and the reservoir on the printing outcome are studied. As a proof-of-concept of the biofunctionalization capability of this 3D printed droplet dispenser, microarrays of oligonucleotides and antibodies displaying high specificity and no cross-contamination are fabricated, and droplets are deposited at the tip of an optical fiber bundle., Competing Interests: Conflict of interestThe authors declare no competing interests., (© The Author(s) 2023.)
- Published
- 2023
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3. Enteropathogen Changes After Rotavirus Vaccine Scale-up.
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Ballard SB, Requena D, Mayta H, Sanchez GJ, Oyola-Lozada MG, Colquechagua Aliaga FD, Cabrera L, Vittet Mondonedo MD, Taquiri C, Tilley CDH, Simons CMP, Meza RA, Bern C, Saito M, Figueroa-Quintanilla DA, and Gilman RH
- Subjects
- Case-Control Studies, Child, Preschool, Diarrhea microbiology, Diarrhea prevention & control, Diarrhea virology, Feces microbiology, Feces virology, Gastroenteritis parasitology, Gastroenteritis virology, Genotype, Humans, Norovirus genetics, Peru, Prospective Studies, Rotavirus genetics, Sapovirus genetics, Severity of Illness Index, Gastroenteritis microbiology, Gastroenteritis prevention & control, Rotavirus Infections prevention & control, Rotavirus Vaccines
- Abstract
Objectives: To inform next steps in pediatric diarrhea burden reduction by understanding the shifting enteropathogen landscape after rotavirus vaccine implementation., Methods: We conducted a case-control study of 1788 medically attended children younger than 5 years, with and without gastroenteritis, after universal rotavirus vaccine implementation in Peru. We tested case and control stools for 5 viruses, 19 bacteria, and parasites; calculated coinfection-adjusted attributable fractions (AFs) to determine pathogen-specific burdens; and evaluated pathogen-specific gastroenteritis severity using Clark and Vesikari scales., Results: Six pathogens were independently positively associated with gastroenteritis: norovirus genogroup II (GII) (AF 29.1, 95% confidence interval [CI]: 28.0-32.3), rotavirus (AF 8.9, 95% CI: 6.8-9.7), sapovirus (AF 6.3, 95% CI: 4.3-7.4), astrovirus (AF 2.8, 95% CI: 0.0-4.0); enterotoxigenic Escherichia coli heat stable and/or heat labile and heat stable (AF 2.4, 95% CI: 0.6-3.1), and Shigella spp. (AF 2.0, 95% CI: 0.4-2.2). Among typeable rotavirus cases, we most frequently identified partially heterotypic strain G12P[8] (54 of 81, 67%). Mean severity was significantly higher for norovirus GII-positive cases relative to norovirus GII-negative cases (Vesikari [12.7 vs 11.8; P < .001] and Clark [11.7 vs 11.4; P = .016]), and cases in the 6- to 12-month age range relative to cases in other age groups (Vesikari [12.7 vs 12.0; P = .0002] and Clark [12.0 vs 11.4; P = .0016])., Conclusions: Norovirus is well recognized as the leading cause of pediatric gastroenteritis in settings with universal rotavirus vaccination. However, sapovirus is often overlooked. Both norovirus and sapovirus contribute significantly to the severe pediatric disease burden in this setting. Decision-makers should consider multivalent vaccine acquisition strategies to target multiple caliciviruses in similar countries after successful rotavirus vaccine implementation., Competing Interests: FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose., (Some authors are military service members or employees of the US Government. This work was prepared as part of their official duties. Title 17 U.S.C. §105 provides that “Copyright protection under this title is not available for any work of the United states Government.” Title 17 USC §101 defines a US Government work as a work prepared by a military service member or employee of the US Government as part of that person’s official duties.)
- Published
- 2022
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4. Following replicative DNA synthesis by time-resolved X-ray crystallography.
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Chim N, Meza RA, Trinh AM, Yang K, and Chaput JC
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- Crystallography, X-Ray, DNA, Bacterial chemistry, DNA, Bacterial genetics, Escherichia coli genetics, Escherichia coli metabolism, Models, Genetic, Nucleic Acid Conformation, Time Factors, DNA Polymerase I metabolism, DNA Replication, DNA, Bacterial metabolism, Escherichia coli Proteins metabolism
- Abstract
The mechanism of DNA synthesis has been inferred from static structures, but the absence of temporal information raises longstanding questions about the order of events in one of life's most central processes. Here we follow the reaction pathway of a replicative DNA polymerase using time-resolved X-ray crystallography to elucidate the order and transition between intermediates. In contrast to the canonical model, the structural changes observed in the time-lapsed images reveal a catalytic cycle in which translocation precedes catalysis. The translocation step appears to follow a push-pull mechanism where the O-O1 loop of the finger subdomain acts as a pawl to facilitate unidirectional movement along the template with conserved tyrosine residues 714 and 719 functioning as tandem gatekeepers of DNA synthesis. The structures capture the precise order of critical events that may be a general feature of enzymatic catalysis among replicative DNA polymerases.
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- 2021
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5. Frontotemporal brain sagging syndrome: Craniospinal hypovolemia secondary to a T6-T7 cerebrospinal fluid-venous fistula.
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Ortega-Porcayo LA, Ortega EP, Quiroz-Castro O, Carrillo-Meza RA, Ponce-Gomez JA, Romano-Feinholz S, Alcocer-Barradas V, de Velasco AR, and Zazueta MO
- Abstract
Background: The frontotemporal brain sagging syndrome (FTBSS) is defined as an insidious/progressive decline in behavior and executive functions, hypersomnolence, and orthostatic headaches attributed to cerebrospinal fluid (CSF) hypovolemia. Here, a T6 CSF-venous fistula (e.g., between the subarachnoid CSF and a paraspinal vein) resulted in a CSF leak responsible for craniospinal hypovolemia., Case Description: A 56-year-old male started with orthostatic headaches and fatigue after scuba diving. His symptoms included progressive, vertigo, tinnitus, nausea, lack of judgment, inappropriate behavior, memory dysfunction, apathy, tremor, orofacial dyskinesia, dysarthria, dysphagia, and hypersomnolence. The lumbar puncture revealed an opening pressure of 0 cm H2O. Magnetic resonance imaging (MRI) findings included brain sagging, bilateral temporal lobe herniation, and pachymeningeal enhancement. The computed tomography (CT) myelogram showed a thoracic diverticulum and a CSF-venous leak at the T6-T7 level. Surgery, which comprised a T6-T7 laminotomy, allowed for dissecting, clipping, and ligating the diverticulum/fistula. The patient improved postoperatively (e.g., cognitive, behavioral, and brainstem symptoms). The follow-up MRI's showed the reversion of the sagging index/uncal herniation., Conclusion: The FTBSS should be considered in the differential diagnosis of an early onset frontotemporal dementia. Establishing the diagnosis and localizing the site of a spinal CSF/venous leak warrant both MRI and myelogram CT studies, to pinpoint the CSF leak site for proper surgical clipping/ligation of these thoracic diverticulum/CSF-venous leaks., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Surgical Neurology International.)
- Published
- 2020
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6. Infection profile in neonatal patients during extracorporeal membrane oxygenation.
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Rodríguez RX, Villarroel LA, Meza RA, Peña JI, Musalem C, Kattan J, and Urzúa S
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Objectives: To describe risk factors for acquired infection during neonatal extracorporeal membrane oxygenation and to examine the predictive value of inflammatory markers in the diagnosis of infection., Methods: A retrospective study was conducted with data for patients under 30 days supported with extracorporeal membrane oxygenation from 2003 to April 2016, in a neonatal intensive care unit., Results: Our study included 160 neonatal patients, the average age of connection was 8.5 days and the duration of extracorporeal membrane oxygenation support was 9.7 days. The incidence of confirmed infection was 23%. Patients with confirmed infection present more frequently: vaginal delivery, lower birth weight, female sex, diagnosis of congenital diaphragmatic hernia, and longer duration of extracorporeal membrane oxygenation. When comparing the group of patients with confirmed infection and suspicion of infection, there were no significant differences in the inflammatory markers. When calculating the slope for each one, the difference in white blood cell count slope 72 h before the infection is significant; in patients with confirmed infection, the count of white blood cell increases (slope: 0.25), versus the group of patients with suspected infection in whom the count decreases (slope: -0.39). No differences were found in other variables., Conclusion: Our study describes that the factors that increase the risk of infection are lower birth weight, vaginal birth, duration of extracorporeal membrane oxygenation, and a positive trend of white blood cell 72 h prior to infection/suspicion. Further studies are necessary to include or definitively rule out the use of these factors and the biomarkers as predictors of infection in neonatal patients supported with extracorporeal membrane oxygenation.
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- 2020
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7. Distribution of Capsular Types of Campylobacter jejuni Isolates from Symptomatic and Asymptomatic Children in Peru.
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Rojas JD, Reynolds ND, Pike BL, Espinoza NM, Kuroiwa J, Jani V, Ríos PA, Nunez RG, Yori PP, Bernal M, Meza RA, Kosek MN, McCoy AJ, Simons MP, Gregory MJ, Guerry P, and Poly FM
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- Asymptomatic Infections epidemiology, Campylobacter Infections diagnosis, Campylobacter jejuni classification, Child, Preschool, DNA, Bacterial genetics, Diarrhea epidemiology, Diarrhea microbiology, Female, Humans, Infant, Male, Peru epidemiology, Prevalence, Prospective Studies, Bacterial Capsules classification, Bacterial Capsules genetics, Campylobacter Infections epidemiology, Campylobacter Infections microbiology, Campylobacter jejuni genetics
- Abstract
Campylobacter jejuni is the leading bacterial cause of diarrhea worldwide. A capsular polysaccharide (CPS) conjugate vaccine is under development and requires determination of the valency. However, distribution of CPS types circulating globally is presently poorly described. We aimed to determine whether CPS type distribution in Peru differs from that in other endemic regions. We used a multiplex polymerase chain reaction (PCR) assay for the detection of CPS encoding genes capable of distinguishing all 35 CPS types on Campylobacter isolates in two prospective communities based studies conducted in cohorts of children less than 59 months of age in Peru. Results showed that CPS type HS4 complex was the most prevalent, followed by HS3 complex and HS15. Differences in CPS type for symptomatology were not statistically significant. Most subjects demonstrated repeated infections over time with different CPS types, suggesting that CPS types may confer of a level of homologous protective immunity. In this dataset, some differences in CPS type distribution were observed in comparison to other low-middle income countries. Further studies need to be conducted in endemic areas to increase our knowledge of CPS type distribution and guide vaccine development.
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- 2019
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8. [Efficacy of viscosupplementation with high and medium molecular weight hyaluronic acid in patients with symptomatic gonarthrosis grades II-III].
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Vázquez-Morales E, Verdugo-Meza RA, Godínez-Alvarado M, and Chávez-Covarrubias G
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- Adult, Aged, Aged, 80 and over, Cross-Sectional Studies, Female, Humans, Hyaluronic Acid, Injections, Intra-Articular, Male, Middle Aged, Molecular Weight, Quality of Life, Retrospective Studies, Treatment Outcome, Osteoarthritis, Knee therapy, Viscosupplementation
- Abstract
Introduction: OA is currently the fifth leading cause of adult disability, its prevalence increases from age 40. Viscosupplementation is a treatment for the early stages of knee OA., Objective: To compare efficacy and quality of life in patients with symptomatic gonartrosis, treated with high and low molecular weight hyaluronic acid., Material and Methods: Analytical, retrospective, cross-sectional, observational study of clinical records of patients diagnosed with grade II and grade III gonarthrosis, October 2017 to June 2018, treated with viscosupplementation with high molecular weight hyaluronic acid or low molecular weight; WOMAC quality of life and scale were analyzed prior to the first application and tracked at two, four and six months., Results: 194 patients, aged between 30 to 87 years (promedio 61.85; SD = 11.3); 134 women (69.1%), 60 men (30.9%). In both groups the evolution was towards improvement, with a decrease in the WOMAC score, with no significant difference between groups. The WOMAC score had a minimum increase after 6 months of application in both groups, which is interpreted as decreasing the therapeutic effect. Two patients had localized minimal adverse reactions which were resolved with general measures., Conclusion: Hyaluronic acid in both presentations, high and low molecular weight, are effective in the treatment of symptomatic goonarthrosis without difference to molecular weight.
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- 2019
9. [Claudication, functional outcomes and quality of life in primary total hip arthroplasty with minimally invasive anterolateral approach].
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Verdugo-Meza RA, González-Castillo CJ, Gaona-Valle S, Salgado-Carbajal E, and Rubí-Flores R
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- Aged, Female, Humans, Longitudinal Studies, Male, Middle Aged, Minimally Invasive Surgical Procedures, Prospective Studies, Treatment Outcome, Arthroplasty, Replacement, Hip, Quality of Life
- Abstract
Introduction: The coxarthrosis has incidence of 88 cases per 100,000 people/year and symptomatic prevalence of 16% men and 6% women aged 65-74 years and increases with age. It is a growing public health disease. Total hip arthroplasty (THA) has become the most successful procedure to increase the quality of life of patients with coxarthrosis. Our objective was to determine the claudication, quality of life and functional results of THA through minimal invasive approach in patients with primary coxarthrosis., Material and Methods: Prospective longitudinal study in patients with unilateral primary coxarthrosis postop of THA with minimally invasive approach from March 2015-February 2016, each patient was analyzed with quality of Life instrument (WOMAC), Functional test for coxarthrosis (HHS) and functional test in patients with hip surgery (OHS) with follow-up of one year., Results: We included 21 patients, 17 female and 4 males corresponding to 80.95% and 19.05% respectively, average age of 59.95 years (ED = 9.64), with excellent functional results to one year according to HHS and OHS, quality of life high in 100% of cases according to WOMAC, with claudication rate of 4.76%., Discussion: The minimal invasive approach is a reproducible surgical technique, with excellent functional results, low claudication rate and high quality of life in postoperative patients of primary ATC at only one year of follow-up.
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- 2019
10. Diabetes in Panama: Epidemiology, Risk Factors, and Clinical Management.
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Mc Donald Posso AJ, Bradshaw Meza RA, Mendoza Morales EA, Jaen Y, Cumbrera Ortega A, and Mendoza Posada EJ
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- Diabetes Mellitus ethnology, Diabetes Mellitus mortality, Female, Humans, Hypertension epidemiology, Male, Overweight epidemiology, Panama epidemiology, Prevalence, Risk Factors, Rural Population, Urban Population, Diabetes Mellitus epidemiology, Triglycerides blood
- Abstract
Objectives: To draw evidence-based conclusions about the epidemiology, drivers, and management of diabetes in Panama based on a literature review and original analyses of large databases., Methods: A search about diabetes in Panama was conducted through PubMed. We used the final reports of 2 studies: the first Survey of Health and Life Quality, 2007, and the first Survey of Risk Factors Associated to Cardiovasular Diseases, 2010-2011, conducted in Panama and analyzed the databases. We reviewed the approach adopted by the Panamanian Social Security institution and the diabetes national guidelines published by the Panamanian Ministry of Health., Findings: The prevalence of diabetes, as estimated in 1 database (ENSCAVI), was 5.4% (4.3% men; 6.0% women; OR = 1.41 [confidence interval 1.26-1.59]; P < 0.0001), with the highest prevalence in urbanized regions. In another database (PREFREC), prevalence was 9.5% (10.3% men and 9.1% women), again higher in urbanized regions, but also in males, older adults, and Afro-Panamanians. Obesity, abdominal obesity, physical inactivity, family history of diabetes, high blood pressure, and triglycerides ≥ 150 mg/dL were associated as risk factors for diabetes in both genders (P < 0.0001). Total cholesterol ≥ 200 mg/dL and high-density lipoprotein cholesterol < 40 mg/dL were risk factors in men (P < 0.0001). In the last 5 years, diabetes was ranked between the sixth and fifth cause of death in Panama. In response, the Panamanian Social Security created the "Program for Prevention and Control of Diabetes" to strengthen primary health care., Conclusions: Diabetes is a serious national public health threat in Panama. To address this problem in a public health modality, information from large databases was analyzed and presented to the Panamanian Ministry of Health to prompt constructive policy change to enhance diabetes prevention., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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