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1.
OTA Int ; 7(3): e337, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38863461

ABSTRACT

Background: Long-bone fractures are a major cause of morbidity worldwide. These injuries are often complicated by infection or nonunion, which significantly affect patient quality of life and economic costs. Although studies have quantified the impact of these fractures, there is not a comprehensive review summarizing their economic and lifestyle costs. Study Objective: This review summarized the impact of long-bone fracture infection and nonunion on health-related quality of life, as measured by utility scores, and both direct and indirect economic costs. Methods: A systematic review was conducted using the following databases: PubMed, EMBASE, Web of Science, and the Cochrane Library. The search included terms related to long-bone fractures, infection, nonunion, cost, and utility. The search yielded 1267 articles, and after deduplication, 1144 were screened, yielding 116 articles for full-text review. Screening was conducted using Covidence and extraction using REDCap. Results: Twenty-two articles met inclusion criteria, with the majority being from the United States and Europe. Most articles were retrospective studies, predominantly regarding the tibia. Fifteen articles contained cost data and 8 contained utility data, with 1 article containing both. Ten cost articles and 1 utility article contained infection data. 8 cost and all utility articles contained nonunion data. Infection ranged from 1.5 to 8.0 times the cost of an uncomplicated fracture. Nonunion ranged from 2.6 to 4.3 times the cost of an uncomplicated fracture. Utility data were variable and ranged from 0.62 to 0.66 for infection and 0.48-0.85 for nonunion. Conclusions: Infection and nonunion after long-bone fractures are associated with large decreases in health-related quality of life and incur substantial costs to both patients and health care systems. The data presented in this review quantify these impacts and may serve useful for future economic analyses. In addition, this study highlights the dearth of high-quality literature on this important topic.

2.
Eur Spine J ; 2024 Jun 24.
Article in English | MEDLINE | ID: mdl-38913179

ABSTRACT

PURPOSE: Kyphosis in the lower lumbar spine (L4-S1) significantly affects sagittal alignment. However, the characteristics of the spinopelvic parameters and compensatory mechanisms in patients with lower lumbar degenerative kyphosis (LLDK) have not been described in detail. The objective of this retrospective study was to analyze the morphological characteristics in patients with sagittal imbalance due to LLDK. METHODS: In this retrospective study, we reviewed the clinical records of consecutive patients who underwent corrective surgery for adult spinal deformity (ASD) at a single institution. We defined LLDK as (i) kyphotic deformity in lower lumbar spine (L4-S1) or (ii) inappropriate distribution of lordosis (lordosis distribution index < 40%) in the lower lumbar spine. Global spine parameters of ASD patients and MRI findings were compared between those with LLDK (LLDK group) and without LLDK (control group). RESULTS: A total of 95 patients were enrolled in this study, of which the LLDK group included 14 patients (14.7%). Compared to the control, LLDK presented significantly higher pelvic incidence (62.1° vs 52.6°) and pelvic tilt (40.0° vs 33.4°), larger lordosis at the thoracolumbar junction (12.0° vs -19.6°), and smaller thoracic kyphosis (9.3° vs 26.0°). In LLDK, there was significantly less disc degeneration at L2/3 and L3/4. CONCLUSION: LLDK patients had high pelvic incidence, large pelvic tilt, and a long compensatory curve at the thoracolumbar junction and thoracic spine region.

3.
J Orthop ; 54: 103-107, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38560590

ABSTRACT

Purpose: There is high burden of long bone fractures in low- and middle-income countries (LMICs). Given a limited availability of fluoroscopy in LMICs, the Surgical Implant Generation Network (SIGN) developed two types of intramedullary nails: the SIGN standard nail and the SIGN Fin Nail. A limited number of studies have analyzed healing outcomes with the SIGN Fin Nail and the current study is the largest one to date. The purpose of this study is to compare outcomes between the SIGN standard nail and SIGN Fin Nails in adult femoral shaft fractures treated with a retrograde approach. Method: A retrospective cohort study of adults with femoral shaft fractures was performed using the Sign Online Surgical Database (SOSD). The primary outcome was achieving full painless weight bearing and the secondary outcomes assessed were radiographic healing and infection. A propensity-score adjustment was performed for potential confounders and effect modification due to fracture location was tested using a Mantel-Haenszel test for heterogeneity. Results: Of 19,928 adults with femoral shaft fractures, 2,912 (14.7%) had the required 6-month follow-up to be included. The overall propensity score weighted relative risk between the Fin and Standard Nail for achieving painless weight-bearing was 0.99, 95% CI [0.96-1.03] and for radiographical healing was 0.99, 95%CI [0.97-1.02]. The propensity score weighted relative risk for infection was 1.30, 95% [0.85-1.97]. Use of the Fin nail was also significantly associated with shorter surgery times (p < 0.005, effect size = 24 min). Sub-group analysis based on fracture location and injury cause demonstrated no change in relative risk. Conclusion: The Fin nail showed no change in relative risk in terms of achieving full painless weightbearing or radiographic healing compared to the standard nail for retrograde nailing of femoral shaft fractures in adults. The heterogeneous nature of the cohort and large sample size allow for generalizability and add to a growing base of literature supporting use of the Fin Nail for retrograde femoral nailing. However, there are limitations as we could not correct for comminution at the fracture site or measure radiographic alignment or shortening.

5.
Environ Res ; 251(Pt 1): 118549, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38412915

ABSTRACT

Antimicrobial Resistance (AMR) poses a global threat to both human health and environmental well-being. Our study delved into Costa Rican wildlife reserves, uncovering a substantial human impact on these ecosystems and underscoring the imperative to pinpoint AMR hotspots. Embracing a One Health perspective, we advocated for a comprehensive landscape analysis that intricately intertwined geographic, climatic, forest, and human factors. This study illuminated the link between laboratory results and observed patterns of antimicrobial use, thereby paving the way for sustainable solutions. Our innovative methodology involved deploying open-ended questions to explore antimicrobial usage across livestock activities, contributing to establishing a comprehensive methodology. Non-invasive sampling in wildlife emerged as a critical aspect, shedding light on areas contaminated by AMR. Feline species, positioned at the apex of the food chain, acted as sentinels for environmental health due to heightened exposure to improperly disposed waste. Regarding laboratory findings, each sample revealed the presence of at least one antimicrobial resistance gene (ARG). Notably, genes encoding resistance to tetracyclines dominated (94.9%), followed by beta-lactams (75.6%), sulfonamides (53.8%), aminoglycosides (51.3%), quinolones (44.9%), phenicols (25.6%), and macrolides (20.5%). Genes encoding polymyxins were not detected. Moreover, 66% of samples carried a multi-resistant microbiome, with 15% exhibiting resistance to three antimicrobial families and 51% to four. The absence of a correlation between forest coverage and ARG presence underscored the profound human impact on wildlife reserves, surpassing previous estimations. This environmental pressure could potentially modify microbiomes and resistomes in unknown ways. As not all antimicrobial families encoding ARGs were utilized by farmers, our next step involved evaluating other human activities to identify the primary sources of contamination. This comprehensive study contributed crucial insights into the intricate dynamics of AMR in natural ecosystems, paving the way for targeted interventions and sustainable coexistence.


Subject(s)
Ecosystem , Animals , Costa Rica , Anti-Bacterial Agents/pharmacology , Cats , Environmental Monitoring/methods , Drug Resistance, Bacterial , Humans
6.
Environ Res ; 242: 117665, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-37993051

ABSTRACT

In this investigation, the presence of antibiotics and pharmaceuticals in Costa Rican surface waters, specifically in regions near feline habitats, was examined. The study revealed that 47% of the water samples contained detectable traces of at least one antibiotic. Ciprofloxacin and norfloxacin were the most frequently detected compounds, each with a detection rate of 27%. Other antibiotics, such as erythromycin, roxithromycin, and trimethoprim, were also found but at lower frequencies, around 14%. Notably, all antibiotic concentrations remained below 10 ng/L, with ciprofloxacin, norfloxacin, and erythromycin showing the highest concentrations. Furthermore, the investigation revealed the presence of non-antibiotic pharmaceutical residues in the water samples, typically at concentrations below 64 ng/L. Tramadol was the most frequently detected compound, present in 18% of the samples. The highest concentrations were observed for acetaminophen and tramadol, measuring 64 and 10 ng/L, respectively. Comparing these findings with studies conducted in treated wastewater and urban rivers, it became evident that the concentrations of antibiotics and pharmaceuticals were notably lower in this study. While previous research reported higher values, the limited number of studies conducted in protected areas raises concerns about the potential environmental impact on biodiversity. In summary, these results emphasize the importance of monitoring pharmaceutical residues and antimicrobial resistance genes ARGs in vulnerable ecosystems, especially those in close proximity to feline habitats in Costa Rica. Additionally, the study delved into the detection of (ARGs). All tested water samples were positive for at least one ARG, with the blaTEM gene being the most prevalent at 82%, followed by tetS at 64% and qnrB at 23%. Moreover, this research shed light on the complexity of evaluating ARGs in environmental samples, as their presence does not necessarily indicate their expression. It also highlighted the potential for co-selection and co-regulation of ARGs, showcasing the intricate behaviors of these genes in aquatic environments.


Subject(s)
Roxithromycin , Tramadol , Water Pollutants, Chemical , Cats , Animals , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/analysis , Costa Rica , Drug Resistance, Bacterial , Norfloxacin , Ecosystem , Ciprofloxacin , Pharmaceutical Preparations , Water , Rivers/chemistry , Environmental Monitoring , Water Pollutants, Chemical/analysis
8.
J Mol Cell Cardiol ; 185: 38-49, 2023 12.
Article in English | MEDLINE | ID: mdl-37890552

ABSTRACT

The cardiac ryanodine receptor (RyR2) is an intracellular Ca2+ release channel vital for the function of the heart. Physiologically, RyR2 is triggered to release Ca2+ from the sarcoplasmic reticulum (SR) which enables cardiac contraction; however, spontaneous Ca2+ leak from RyR2 has been implicated in the pathophysiology of heart failure (HF). RyR2 channels have been well documented to assemble into clusters within the SR membrane, with the organisation of RyR2 clusters recently gaining interest as a mechanism by which the occurrence of pathological Ca2+ leak is regulated, including in HF. In this review, we explain the terminology relating to key nanoscale RyR2 clustering properties as both single clusters and functionally grouped Ca2+ release units, with a focus on the advancements in super-resolution imaging approaches which have enabled the detailed study of cluster organisation. Further, we discuss proposed mechanisms for modulating RyR2 channel organisation and the debate regarding the potential impact of cluster organisation on Ca2+ leak activity. Finally, recent experimental evidence investigating the nanoscale remodelling and functional alterations of RyR2 clusters in HF is discussed with consideration of the clinical implications.


Subject(s)
Heart Failure , Ryanodine Receptor Calcium Release Channel , Humans , Ryanodine Receptor Calcium Release Channel/metabolism , Myocytes, Cardiac/metabolism , Calcium Signaling , Sarcoplasmic Reticulum/metabolism , Calcium/metabolism
9.
J Mol Cell Cardiol ; 184: 75-87, 2023 11.
Article in English | MEDLINE | ID: mdl-37805125

ABSTRACT

Caveolae are tiny invaginations in the sarcolemma that buffer extra membrane and contribute to mechanical regulation of cellular function. While the role of caveolae in membrane mechanosensation has been studied predominantly in non-cardiomyocyte cells, caveolae contribution to cardiac mechanotransduction remains elusive. Here, we studied the role of caveolae in the regulation of Ca2+ signaling in atrial cardiomyocytes. In Langendorff-perfused mouse hearts, atrial pressure/volume overload stretched atrial myocytes and decreased caveolae density. In isolated cells, caveolae were disrupted through hypotonic challenge that induced a temporal (<10 min) augmentation of Ca2+ transients and caused a rise in Ca2+ spark activity. Similar changes in Ca2+ signaling were observed after chemical (methyl-ß-cyclodextrin) and genetic ablation of caveolae in cardiac-specific conditional caveolin-3 knock-out mice. Acute disruption of caveolae, both mechanical and chemical, led to the elevation of cAMP level in the cell interior, and cAMP-mediated augmentation of protein kinase A (PKA)-phosphorylated ryanodine receptors (at Ser2030 and Ser2808). Caveolae-mediated stimulatory effects on Ca2+ signaling were abolished via inhibition of cAMP production by adenyl cyclase antagonists MDL12330 and SQ22536, or reduction of PKA activity by H-89. A compartmentalized mathematical model of mouse atrial myocytes linked the observed changes to a microdomain-specific decrease in phosphodiesterase activity, which disrupted cAMP signaling and augmented PKA activity. Our findings add a new dimension to cardiac mechanobiology and highlight caveolae-associated cAMP/PKA-mediated phosphorylation of Ca2+ handling proteins as a novel component of mechano-chemical feedback in atrial myocytes.


Subject(s)
Atrial Fibrillation , Myocytes, Cardiac , Mice , Animals , Myocytes, Cardiac/metabolism , Caveolae/metabolism , Mechanotransduction, Cellular , Atrial Fibrillation/metabolism , Cyclic AMP/metabolism , Signal Transduction/physiology
10.
Structure ; 31(7): 790-800.e4, 2023 07 06.
Article in English | MEDLINE | ID: mdl-37192614

ABSTRACT

The coordinated release of Ca2+ from the sarcoplasmic reticulum (SR) is critical for excitation-contraction coupling. This release is facilitated by ryanodine receptors (RyRs) that are embedded in the SR membrane. In skeletal muscle, activity of RyR1 is regulated by metabolites such as ATP, which upon binding increase channel open probability (Po). To obtain structural insights into the mechanism of RyR1 priming by ATP, we determined several cryo-EM structures of RyR1 bound individually to ATP-γ-S, ADP, AMP, adenosine, adenine, and cAMP. We demonstrate that adenine and adenosine bind RyR1, but AMP is the smallest ATP derivative capable of inducing long-range (>170 Å) structural rearrangements associated with channel activation, establishing a structural basis for key binding site interactions that are the threshold for triggering quaternary structural changes. Our finding that cAMP also induces these structural changes and results in increased channel opening suggests its potential role as an endogenous modulator of RyR1 conductance.


Subject(s)
Nucleotides , Ryanodine Receptor Calcium Release Channel , Adenine/metabolism , Adenosine/metabolism , Adenosine Monophosphate/metabolism , Adenosine Triphosphate/metabolism , Calcium/metabolism , Muscle, Skeletal/metabolism , Nucleotides/metabolism , Ryanodine Receptor Calcium Release Channel/chemistry , Humans , Animals , Rabbits
11.
Life (Basel) ; 13(4)2023 Apr 14.
Article in English | MEDLINE | ID: mdl-37109544

ABSTRACT

The mitochondrial splice variant of the sulfonylurea receptor (SUR2A-55) is associated with protection from myocardial ischemia-reperfusion (IR) injury, increased mitochondrial ATP sensitive K+ channel activity (mitoKATP) and altered glucose metabolism. While mitoKATP channels composed of CCDC51 and ABCB8 exist, the mitochondrial K+ pore regulated by SUR2A-55 is unknown. We explored whether SUR2A-55 regulates ROMK to form an alternate mitoKATP. We assessed glucose uptake in mice overexpressing SUR2A-55 (TGSUR2A-55) compared with WT mice during IR injury. We then examined the expression level of ROMK and the effect of ROMK modulation on mitochondrial membrane potential (Δψm) in WT and TGSUR2A-55 mice. TGSUR2A-55 had increased glucose uptake compared to WT mice during IR injury. The expression of ROMK was similar in WT compared to TGSUR2A-55 mice. ROMK inhibition hyperpolarized resting cardiomyocyte Δψm from TGSUR2A-55 mice but not from WT mice. In addition, TGSUR2A-55 and ROMK inhibitor treated WT isolated cardiomyocytes had enhanced mitochondrial uncoupling. ROMK inhibition blocked diazoxide induced Δψm depolarization and prevented preservation of Δψm from FCCP perfusion in WT and to a lesser degree TGSUR2A-55 mice. In conclusion, cardio-protection from SUR2A-55 is associated with ROMK regulation, enhanced mitochondrial uncoupling and increased glucose uptake.

12.
J Wildl Dis ; 59(1): 12-23, 2023 01 01.
Article in English | MEDLINE | ID: mdl-36762840

ABSTRACT

Human activities such as habitat degradation and fragmentation threaten biodiversity in Neotropical areas. This work proposes an analytical methodology to identify natural areas in Central America with anthropogenic impact, analyzing the presence of antimicrobial resistance genes (ARGs) in accordance with their theoretical relationship with human-related activities. Sixteen ARGs were quantified in feces of different individuals of 13 jaguars (Panthera onca) and 13 pumas (Puma concolor) in three conservation areas in Costa Rica by real-time PCR. At least one ARG was detected in all samples. Of the ARGs encoding tetracycline resistance, the most frequent were tetQ and tetY (85% and 69%, respectively). The sulfonamides (sulI and sulII; 69% each), phenicols (catI and catII; 19% and 54%, respectively), and quinolones (qnrS; 12%) were also detected. The presence of human settlements, livestock farms (pigs, cattle, and poultry), roads, human health centers, flood zones, and rivers were identified within each area to generate an index of human activity. We found no difference between the presence of ARG by roads, agricultural activities, and human settlements (P>0.05). However, tetW showed higher percentages with porcine and bovine farms; both tetY and tetW were more frequent in jaguars than in pumas. Of concern is that many of the most contaminated samples were taken from national parks, such as Braulio Carrillo and Tortuguero, where animals should not have direct contact with humans.


Subject(s)
Panthera , Puma , Animals , Humans , Cattle , Swine , Anti-Bacterial Agents , Anthropogenic Effects , Drug Resistance, Bacterial , Ecosystem
13.
Injury ; 54(5): 1287-1291, 2023 May.
Article in English | MEDLINE | ID: mdl-36759310

ABSTRACT

INTRODUCTION: Prior studies have shown that the surgical stabilization of rib fractures (SSRF) for patients with multiple rib fractures is associated with improved outcomes by restoring chest wall integrity and decreasing time to return to prior functional status. It is unclear if patients with pulmonary comorbidities (PCM) would benefit from this procedure. OBJECTIVE: To compare the difference in morbidity and mortality of patients with multiple rib fractures undergoing SSRF who have underlying PCM to those who do not have PCM. METHODS: We performed a retrospective cohort study of patients with multiple rib fractures using data from the Trauma Quality Improvement Program (January 2015 to December 2018). Patients with penetrating injuries, those who died within the first 24 h, those with substantial head, spine, or abdominopelvic injuries, and those who were pregnant, were excluded. A PCM was defined as chronic lower respiratory disease, active smoking, or morbid obesity. Dichotomous outcomes were adjusted for potential confounders by creating a propensity score for PCM and applying inverse probability weighting. The propensity score accounted for multiple patient-level and hospital level covariates. Continuous outcomes were adjusted for these same covariates using multivariable quantile regression. RESULTS: Of the 4,084 patients who underwent SSRF, 3048 (75%) were males, the median age was 57 years [IQR 47, 66], and 1504 (37%) had at least one PCM. After adjusting for the propensity score, patients with PCM who underwent SSRF had no significant difference in mortality compared to those without PCM (absolute difference, 0.7% [95% CI -0.2, 1.7]). Similarly, there was no significant difference in time on the ventilator (0.6 days [-0.1, 1.4]). Patients with PCM, however, had a statistically significantly longer hospital LOS (0.8 days [0.3, 1.3]) and ICU LOS (0.6 days [0.1, 1.1]), higher risk of tracheostomy (2.7% [0.1, 4.6]) and higher probability of pulmonary complications (2.7% [1.2, 4.2]), compared to those without PCM. CONCLUSION: Among patients with multiple rib fractures who undergo SSRF, having a PCM did not result in a clinically important higher probability of dying or experiencing substantial morbidity. This factor should not exclude patients with PCM from receiving SSRF for multiple rib fractures but the small increased risk in morbidity should be discussed with patients prior to SSRF.


Subject(s)
Rib Fractures , Spinal Fractures , Thoracic Wall , Male , Humans , Middle Aged , Female , Rib Fractures/complications , Rib Fractures/surgery , Retrospective Studies , Fracture Fixation/methods , Fracture Fixation, Internal/methods , Spinal Fractures/complications , Length of Stay
15.
Ann Intern Med ; 175(8): JC88, 2022 08.
Article in English | MEDLINE | ID: mdl-35914255

ABSTRACT

SOURCE CITATION: Ezekowitz JA, Colin-Ramirez E, Ross H, et al. Reduction of dietary sodium to less than 100 mmol in heart failure (SODIUM-HF): an international, open-label, randomised, controlled trial. Lancet. 2022;399:1391-400. 35381194.


Subject(s)
Heart Failure , Sodium, Dietary , Humans , Sodium Chloride, Dietary
16.
Toxics ; 10(7)2022 Jun 22.
Article in English | MEDLINE | ID: mdl-35878251

ABSTRACT

The Volcán River watershed in the south Pacific of Costa Rica comprises forests, small urban settlements, cattle fields, and intensive agriculture (mostly pineapple and sugarcane). The ecological integrity and quality of its waters was assessed from 2011-2013 and 2018-2019 by means of physical-chemical parameters (pH, conductivity, temperature, DO, DBO, nitrate, total phosphorus, and pesticide residues) and benthic macroinvertebrate (MI) sampling in eight sites (Volcán, Cañas, and Ángel Rivers, and Peje and Maura streams), resulting in high ecological integrity in all sites except the Peje stream, which is polluted with nitrates and pesticides. Only in this stream was there a marked seasonal variation in the abundance of 16 MI families including Leptohyphidae, Leptophlebiidae, Philopotamidae, Glossossomatidae, and Corydalidae, among others, whose presence was limited exclusively to the dry season (December to April), disappearing from the stream in the rainy season, with corresponding peaks in nitrate (max 20.3 mg/L) and pesticides (mainly herbicides and organophosphate insecticides). The characteristics of the watershed, with large areas of forest and excellent water quality, allow for the re-colonization of organisms into the Peje stream; however, those organisms are incapable of development and growth, providing evidence of a contaminant-driven habitat fragmentation in this stream during the rainy season.

17.
mBio ; 13(4): e0084022, 2022 08 30.
Article in English | MEDLINE | ID: mdl-35735743

ABSTRACT

Global population immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is accumulating through heterogeneous combinations of infection and vaccination. Vaccine distribution in low- and middle-income countries has been variable and reliant on diverse vaccine platforms. We studied B-cell immunity in Mexico, a middle-income country where five different vaccines have been deployed to populations with high SARS-CoV-2 incidences. Levels of antibodies that bound a stabilized prefusion spike trimer, neutralizing antibody titers, and memory B-cell expansion correlated with each other across vaccine platforms. Nevertheless, the vaccines elicited variable levels of B-cell immunity, and the majority of recipients had undetectable neutralizing activity against the recently emergent omicron variant. SARS-CoV-2 infection, experienced before or after vaccination, potentiated B-cell immune responses and enabled the generation of neutralizing activity against omicron and SARS-CoV for all vaccines in nearly all individuals. These findings suggest that broad population immunity to SARS-CoV-2 will eventually be achieved but by heterogeneous paths. IMPORTANCE The majority of studies on SARS-CoV-2 vaccine-elicited immunity and immune evasion have focused on single vaccines corresponding to those distributed in high-income countries. However, in low- and middle-income countries, vaccine deployment has been far less uniform. It is therefore important to determine the levels of immunity elicited by vaccines that have been deployed globally. Such data should help inform policy. Thus, this paper is very much a "real-world" study that focuses on a middle-income country, Mexico, in which five different vaccines based on mRNA, adenovirus, and inactivated-virus platforms have been extensively deployed, while (as documented in our study) SARS-CoV-2 variants with increasing degrees of immune evasiveness have propagated in the Mexican population, culminating in the recent emergence of B.1.1.529 (omicron).


Subject(s)
COVID-19 , Viral Vaccines , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Humans , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
18.
J Mol Cell Cardiol ; 167: 118-128, 2022 06.
Article in English | MEDLINE | ID: mdl-35413295

ABSTRACT

Ryanodine receptor 2 (RyR2) is an ion channel in the heart responsible for releasing into the cytosol most of the Ca2+ required for contraction. Proper regulation of RyR2 is critical, as highlighted by the association between channel dysfunction and cardiac arrhythmia. Lower RyR2 expression is also observed in some forms of heart disease; however, there is limited information on the impact of this change on excitation-contraction (e-c) coupling, Ca2+-dependent arrhythmias, and cardiac performance. We used a constitutive knock-out of RyR2 in rabbits (RyR2-KO) to assess the extent to which a stable decrease in RyR2 expression modulates Ca2+ handling in the heart. We found that homozygous knock-out of RyR2 in rabbits is embryonic lethal. Remarkably, heterozygotes (KO+/-) show ~50% loss of RyR2 protein without developing an overt phenotype at the intact animal and whole heart levels. Instead, we found that KO+/- myocytes show (1) remodeling of RyR2 clusters, favoring smaller groups in which channels are more densely arranged; (2) lower Ca2+ spark frequency and amplitude; (3) slower rate of Ca2+ release and mild but significant desynchronization of the Ca2+ transient; and (4) a significant decrease in the basal phosphorylation of S2031, likely due to increased association between RyR2 and PP2A. Our data show that RyR2 deficiency, although remarkable at the molecular and subcellular level, has only a modest impact on global Ca2+ release and is fully compensated at the whole-heart level. This highlights the redundancy of RyR2 protein expression and the plasticity of the e-c coupling apparatus.


Subject(s)
Adrenergic Agents , Ryanodine Receptor Calcium Release Channel , Animals , Arrhythmias, Cardiac/metabolism , Calcium/metabolism , Calcium Signaling , Excitation Contraction Coupling , Myocytes, Cardiac/metabolism , Rabbits , Ryanodine Receptor Calcium Release Channel/genetics , Ryanodine Receptor Calcium Release Channel/metabolism , Sarcoplasmic Reticulum/metabolism
19.
medRxiv ; 2022 Feb 08.
Article in English | MEDLINE | ID: mdl-35169812

ABSTRACT

Global population immunity to SARS-CoV-2 is accumulating through heterogenous combinations of infection and vaccination. Vaccine distribution in low- and middle-income countries has been variable and reliant on diverse vaccine platforms. We studied B-cell immunity in Mexico, a middle-income country where five different vaccines have been deployed to populations with high SARS-CoV-2 incidence. Levels of antibodies that bound a stabilized prefusion spike trimer, neutralizing antibody titers and memory B-cell expansion correlated with each other across vaccine platforms. Nevertheless, the vaccines elicited variable levels of B-cell immunity, and the majority of recipients had undetectable neutralizing activity against the recently emergent omicron variant. SARS-CoV-2 infection, experienced prior to or after vaccination potentiated B-cell immune responses and enabled the generation of neutralizing activity against omicron and SARS-CoV for all vaccines in nearly all individuals. These findings suggest that broad population immunity to SARS-CoV-2 will eventually be achieved, but by heterogenous paths.

20.
Vector Borne Zoonotic Dis ; 21(9): 720-726, 2021 09.
Article in English | MEDLINE | ID: mdl-34255563

ABSTRACT

Objective: The aim of this study is to describe the main clinical phenotypes, laboratory findings, and severity of coronavirus disease 2019 (COVID-19) in patients hospitalized at the High Specialty Medical Unit # 71 of the Mexican Social Security Institute. Methods: Prospective observational cohort study with a total of 105 patients hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at the High Specialty Medical Unit # 71 (Torreón, Coahuila, Mexico), from May 15th to August 15th, 2020. The cases were confirmed to be COVID-19 positive through an RT-qPCR test. Clinical phenotypes and laboratory tests were evaluated to determine the degree of severity of the disease and the most frequent comorbidities. Results: The clinical characteristics of a total of 105 hospitalized patients (47 females and 58 males; median age being 52 years) with confirmed COVID-19 diagnoses were studied. The severity of the disease was classified as moderate grade (62.7%), severe grade (21.5%), and critical grade (15.6%). Among the most frequent underlying pathologies coexisted overweight (n = 75, 78.12%), obesity (n = 21, 21.87%), diabetes (n = 10, 9.52%), and hypertension (n = 6, 5.71%), some of these patients present more than one pathology. This association was found with diabetes (odds ratio [OR]: 1.42; 95% confidence interval [CI]: 1.23-1.97; p = 0.021) and high levels of D-dimer (OR: 1.01; 95% CI: 1.00-1.08; p = 0.001). Conclusion: In this retrospective cohort study of patients with COVID-19 from a specialty hospital in the northeast region of Mexico, it was observed that clinical phenotypes and D-dimer elevation were compatible with an inflammatory state by degree of severity; it was found that the hospitalized patients with underlying chronic medical conditions such as diabetes and elevated D-dimer levels were significantly associated with increased mortality from COVID-19. Age and sex (males) were two factors highly associated with mortality.


Subject(s)
COVID-19/epidemiology , COVID-19/pathology , SARS-CoV-2 , Adult , Aged , Aging , Cohort Studies , Diabetes Mellitus, Type 2/complications , Female , Fibrin Fibrinogen Degradation Products , Humans , Male , Mexico/epidemiology , Middle Aged , Phenotype , Prospective Studies , Risk Factors , Sex Factors
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