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1.
Int J Mol Sci ; 25(9)2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38731864

RESUMO

The human brain possesses three predominate phospholipids, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS), which account for approximately 35-40%, 35-40%, and 20% of the brain's phospholipids, respectively. Mitochondrial membranes are relatively diverse, containing the aforementioned PC, PE, and PS, as well as phosphatidylinositol (PI) and phosphatidic acid (PA); however, cardiolipin (CL) and phosphatidylglycerol (PG) are exclusively present in mitochondrial membranes. These phospholipid interactions play an essential role in mitochondrial fusion and fission dynamics, leading to the maintenance of mitochondrial structural and signaling pathways. The essential nature of these phospholipids is demonstrated through the inability of mitochondria to tolerate alteration in these specific phospholipids, with changes leading to mitochondrial damage resulting in neural degeneration. This review will emphasize how the structure of phospholipids relates to their physiologic function, how their metabolism facilitates signaling, and the role of organ- and mitochondria-specific phospholipid compositions. Finally, we will discuss the effects of global ischemia and reperfusion on organ- and mitochondria-specific phospholipids alongside the novel therapeutics that may protect against injury.


Assuntos
Encéfalo , Parada Cardíaca , Mitocôndrias , Fosfolipídeos , Humanos , Fosfolipídeos/metabolismo , Mitocôndrias/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Parada Cardíaca/metabolismo , Transdução de Sinais , Membranas Mitocondriais/metabolismo , Dinâmica Mitocondrial
2.
Life (Basel) ; 14(4)2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38672748

RESUMO

BACKGROUND: Mitochondrial dysfunction, which is triggered by systemic ischemia-reperfusion (IR) injury and affects various organs, is a key factor in the development of post-cardiac arrest syndrome (PCAS). Current research on PCAS primarily addresses generalized mitochondrial responses, resulting in a knowledge gap regarding organ-specific mitochondrial dynamics. This review focuses on the organ-specific mitochondrial responses to IR injury, particularly examining the brain, heart, and kidneys, to highlight potential therapeutic strategies targeting mitochondrial dysfunction to enhance outcomes post-IR injury. METHODS AND RESULTS: We conducted a narrative review examining recent advancements in mitochondrial research related to IR injury. Mitochondrial responses to IR injury exhibit considerable variation across different organ systems, influenced by unique mitochondrial structures, bioenergetics, and antioxidative capacities. Each organ demonstrates distinct mitochondrial behaviors that have evolved to fulfill specific metabolic and functional needs. For example, cerebral mitochondria display dynamic responses that can be both protective and detrimental to neuronal activity and function during ischemic events. Cardiac mitochondria show vulnerability to IR-induced oxidative stress, while renal mitochondria exhibit a unique pattern of fission and fusion, closely linked to their susceptibility to acute kidney injury. This organ-specific heterogeneity in mitochondrial responses requires the development of tailored interventions. Progress in mitochondrial medicine, especially in the realms of genomics and metabolomics, is paving the way for innovative strategies to combat mitochondrial dysfunction. Emerging techniques such as mitochondrial transplantation hold the potential to revolutionize the management of IR injury in resuscitation science. CONCLUSIONS: The investigation into organ-specific mitochondrial responses to IR injury is pivotal in the realm of resuscitation research, particularly within the context of PCAS. This nuanced understanding holds the promise of revolutionizing PCAS management, addressing the unique mitochondrial dysfunctions observed in critical organs affected by IR injury.

3.
J Transl Med ; 22(1): 230, 2024 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-38433198

RESUMO

BACKGROUND: Mitochondrial transplantation (MTx) has emerged as a novel therapeutic strategy, particularly effective in diseases characterized by mitochondrial dysfunction. This review synthesizes current knowledge on MTx, focusing on its role in modulating immune responses and explores its potential in treating post-cardiac arrest syndrome (PCAS). METHODS: We conducted a comprehensive narrative review of animal and human studies that have investigated the effects of MTx in the context of immunomodulation. This included a review of the immune responses following critical condition such as ischemia reperfusion injury, the impact of MTx on these responses, and the therapeutic potential of MTx in various conditions. RESULTS: Recent studies indicate that MTx can modulate complex immune responses and reduce ischemia-reperfusion injury post-CA, suggesting MTx as a novel, potentially more effective approach. The review highlights the role of MTx in immune modulation, its potential synergistic effects with existing treatments such as therapeutic hypothermia, and the need for further research to optimize its application in PCAS. The safety and efficacy of autologous versus allogeneic MTx, particularly in the context of immune reactions, are critical areas for future investigation. CONCLUSION: MTx represents a promising frontier in the treatment of PCAS, offering a novel approach to modulate immune responses and restore cellular energetics. Future research should focus on long-term effects, combination therapies, and personalized medicine approaches to fully harness the potential of MTx in improving patient outcomes in PCAS.


Assuntos
Parada Cardíaca , Hipotermia Induzida , Traumatismo por Reperfusão , Animais , Humanos , Terapia Combinada , Medicina de Precisão , Parada Cardíaca/terapia , Imunomodulação , Traumatismo por Reperfusão/terapia
4.
J Investig Med ; 72(2): 248-255, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38102744

RESUMO

Telemedicine is seen as a useful tool in reducing gaps in health care but this technology-enabled care can also exacerbate health inequity if not implemented with a focus on inclusivity. Though many studies have reported improvements as well as exacerbation of disparities in access to care in their telehealth programs, there does not exist a common evaluation tool to assess these programs. To mitigate the impact of COVID-19 on health care workers and protect medically vulnerable children, in March 2020 we expanded our pre-established specialty and subspecialty direct-to-patient pediatric telemedicine program in a high volume urban pediatric health system. Our program aimed to prevent disparities in pediatric health care. In this study, using a "Pillars of Access" approach as a model to evaluate impact and access to care of our direct-to-patient telemedicine program, we analyzed the patients that were seen pre-COVID versus post-COVID. Our study demonstrated an increase in telemedicine visits for patients from diverse socioeconomic and racial backgrounds, and geographically underserved communities. We also observed an increase in telemedicine visits for mental health complaints and for certain categories of high-risk patients. This study was not designed to identify language and cultural barriers to telemedicine. Future identification of these specific barriers is needed. The tool to evaluate telehealth impact/access to care through a "Pillars of Access" approach presented here could serve as a model for implementation of telehealth programs. Our study highlights telemedicine programs as a mechanism to address healthcare inequity and overcome barriers to care.


Assuntos
COVID-19 , Telemedicina , Criança , Humanos , Atenção à Saúde , COVID-19/epidemiologia , Desigualdades de Saúde
5.
Small ; 19(41): e2300144, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37329196

RESUMO

A key advantage of utilizing van-der-Waals (vdW) materials as defect-hosting platforms for quantum applications is the controllable proximity of the defect to the surface or the substrate allowing for improved light extraction, enhanced coupling with photonic elements, or more sensitive metrology. However, this aspect results in a significant challenge for defect identification and characterization, as the defect's properties depend on the the atomic environment. This study explores how the environment can influence the properties of carbon impurity centers in hexagonal boron nitride (hBN). It compares the optical and electronic properties of such defects between bulk-like and few-layer films, showing alteration of the zero-phonon line energies and their phonon sidebands, and enhancements of inhomogeneous broadenings. To disentangle the mechanisms responsible for these changes, including the atomic structure, electronic wavefunctions, and dielectric screening, it combines ab initio calculations with a quantum-embedding approach. By studying various carbon-based defects embedded in monolayer and bulk hBN, it demonstrates that the dominant effect of the change in the environment is the screening of density-density Coulomb interactions between the defect orbitals. The comparative analysis of experimental and theoretical findings paves the way for improved identification of defects in low-dimensional materials and the development of atomic scale sensors for dielectric environments.

6.
Phys Rev Lett ; 130(8): 086701, 2023 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-36898102

RESUMO

Conventional approaches for lattice dynamics based on static interatomic forces do not fully account for the effects of time-reversal-symmetry breaking in magnetic systems. Recent approaches to rectify this involve incorporating the first-order change in forces with atomic velocities under the assumption of adiabatic separation of electronic and nuclear degrees of freedom. In this Letter, we develop a first-principles method to calculate this velocity-force coupling in extended solids and show via the example of ferromagnetic CrI_{3} that, due to the slow dynamics of the spins in the system, the assumption of adiabatic separation can result in large errors for splittings of zone-center chiral modes. We demonstrate that an accurate description of the lattice dynamics requires treating magnons and phonons on the same footing.

7.
Nano Lett ; 22(18): 7401-7407, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36122409

RESUMO

The optical properties of transition-metal dichalcogenides have previously been modified at the nanoscale by using mechanical and electrical nanostructuring. However, a clear experimental picture relating the local electronic structure with emission properties in such structures has so far been lacking. Here, we use a combination of scanning tunneling microscopy (STM) and near-field photoluminescence (nano-PL) to probe the electronic and optical properties of single nanobubbles in bilayer heterostructures of WSe2 on MoSe2. We show from tunneling spectroscopy that there are electronic states deeply localized in the gap at the edge of such bubbles, which are independent of the presence of chemical defects in the layers. We also show a significant change in the local band gap on the bubble, with a continuous evolution to the edge of the bubble over a length scale of ∼20 nm. Nano-PL measurements observe a continuous redshift of the interlayer exciton on entering the bubble, in agreement with the band-to-band transitions measured by STM. We use self-consistent Schrödinger-Poisson simulations to capture the essence of the experimental results and find that strong doping in the bubble region is a key ingredient to achieving the observed localized states, together with mechanical strain.

8.
Phys Rev Lett ; 128(9): 095901, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35302830

RESUMO

In insulators, Born effective charges describe the electrical polarization induced by the displacement of individual atomic sublattices. Such a physical property is at first sight irrelevant for metals and doped semiconductors, where the macroscopic polarization is ill defined. Here we show that, in clean conductors, going beyond the adiabatic approximation results in nonadiabatic Born effective charges that are well defined in the low-frequency limit. In addition, we find that the sublattice sum of the nonadiabatic Born effective charges does not vanish as it does in the insulating case, but instead is proportional to the Drude weight. We demonstrate these formal results with density functional perturbation theory calculations of Al and electron-doped SnS_{2} and SrTiO_{3}.

9.
Mitochondrion ; 60: 112-120, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34384933

RESUMO

Cardiac arrest (CA) induces whole-body ischemia resulting in mitochondrial dysfunction. We used isolated mitochondria to examine phospholipid alterations in the brain, heart, kidney, and liver post-CA. Our data shows that ischemia/reperfusion most significantly alters brain mitochondria phospholipids, predominately after resuscitation. Furthermore, the alterations do not appear to be a function of dysregulated importation of phospholipids, but caused by impaired intra-mitochondrial synthesis and/or remodeling of phospholipids. Our data demonstrates only brain mitochondria undergo significant alterations in phospholipids, providing a rationale for the high vulnerability of the brain to ischemia/reperfusion. Furthermore, analyzing this pathophysiologic state provides insight into physiologic mitochondrial phospholipid metabolism.


Assuntos
Encéfalo/metabolismo , Parada Cardíaca/metabolismo , Mitocôndrias/metabolismo , Miocárdio/metabolismo , Fosfolipídeos/metabolismo , Animais , Rim/metabolismo , Fígado/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley
10.
Endosc Int Open ; 9(5): E701-E705, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33937511

RESUMO

Background and study aims The COVID-19 pandemic has disrupted routine medical care due to uncertainty regarding the risk of viral spread. One major concern for viral transmission to both patients and providers is performing aerosol-generating procedures such as endoscopy. As such, we performed a prospective study to examine the extent of viral contamination present in the local environment before and after endoscopic procedures on COVID-19 positive patients. Materials and methods A total of 82 samples were collected from 23 surfaces in the procedure area of four COVID-positive patients undergoing upper endoscopic procedures. Samples were collected both before and after the procedure. severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was extracted and quantified using reverse transcription quantitative polymerase chain reaction with primers to detect nucleocapsid RNA, and results reported as the number of viral copies per square centimeter of contaminated surface. Results A total of six positive samples were detected from three of the four patients. The floor beneath the patient bed was the most common site of viral RNA, but RNA was also detected on the ventilator monitor prior to the procedure and the endoscope after the procedure. Conclusions The risk of SARS-CoV-2 transmission associated with upper endoscopy procedures is low based on the low rate of surface contamination. Some surfaces in close proximity to the patient and endoscopist may pose a higher risk for contamination. Patient positioning and oxygen delivery methods may influence the directionality and extent of viral spread. Our results support the use of appropriate personal protection to minimize risk of viral transmission.

11.
J Transl Med ; 19(1): 214, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001191

RESUMO

BACKGROUND: Mitochondria are essential organelles that provide energy for cellular functions, participate in cellular signaling and growth, and facilitate cell death. Based on their multifactorial roles, mitochondria are also critical in the progression of critical illnesses. Transplantation of mitochondria has been reported as a potential promising approach to treat critical illnesses, particularly ischemia reperfusion injury (IRI). However, a systematic review of the relevant literature has not been conducted to date. Here, we systematically reviewed the animal and human studies relevant to IRI to summarize the evidence for mitochondrial transplantation. METHODS: We searched MEDLINE, the Cochrane library, and Embase and performed a systematic review of mitochondrial transplantation for IRI in both preclinical and clinical studies. We developed a search strategy using a combination of keywords and Medical Subject Heading/Emtree terms. Studies including cell-mediated transfer of mitochondria as a transfer method were excluded. Data were extracted to a tailored template, and data synthesis was descriptive because the data were not suitable for meta-analysis. RESULTS: Overall, we identified 20 animal studies and two human studies. Among animal studies, 14 (70%) studies focused on either brain or heart IRI. Both autograft and allograft mitochondrial transplantation were used in 17 (85%) animal studies. The designs of the animal studies were heterogeneous in terms of the route of administration, timing of transplantation, and dosage used. Twelve (60%) studies were performed in a blinded manner. All animal studies reported that mitochondrial transplantation markedly mitigated IRI in the target tissues, but there was variation in biological biomarkers and pathological changes. The human studies were conducted with a single-arm, unblinded design, in which autologous mitochondrial transplantation was applied to pediatric patients who required extracorporeal membrane oxygenation (ECMO) for IRI-associated myocardial dysfunction after cardiac surgery. CONCLUSION: The evidence gathered from our systematic review supports the potential beneficial effects of mitochondrial transplantation after IRI, but its clinical translation remains limited. Further investigations are thus required to explore the mechanisms of action and patient outcomes in critical settings after mitochondrial transplantation. Systematic review registration The study was registered at UMIN under the registration number UMIN000043347.


Assuntos
Traumatismo por Reperfusão , Animais , Morte Celular , Criança , Humanos , Mitocôndrias , Traumatismo por Reperfusão/terapia
12.
Artigo em Inglês | MEDLINE | ID: mdl-33802332

RESUMO

Background: Health care systems in the United States are continuously expanding and contracting spaces to treat patients with coronavirus disease 2019 (COVID-19) in intensive care units (ICUs). As a result, hospitals must effectively decontaminate and contain severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in constructed and deconstructed ICUs that care for patients with COVID-19. We assessed decontamination of a COVID-19 ICU and examined the containment efficacy of combined contact and droplet precautions in creating and maintaining a SARS-CoV-2-negative ICU "antechamber". Methods: To examine the efficacy of chemical decontamination, we used high-density, semi-quantitative environmental sampling to detect SARS-CoV-2 on surfaces in a COVID-19 ICU and COVID-19 ICU antechamber. Quantitative real-time polymerase chain reaction was used to measure viral RNA on surfaces. Viral location mapping revealed the distribution of viral RNA in the COVID-19 ICU and COVID-19 ICU antechamber. Results were further assessed using loop-mediated isothermal amplification. Results: We collected 224 surface samples pre-decontamination and 193 samples post-decontamination from a COVID-19 ICU and adjoining COVID-19 ICU antechamber. We found that 46% of antechamber objects were positive for SARS-CoV-2 pre-decontamination despite the construction of a swinging door barrier system, implementation of contact precautions, and installation of high-efficiency particulate air filters. The object positivity rate reduced to 32.1% and viral particle rate reduced by 95.4% following decontamination. Matched items had an average of 432.2 ± 2729 viral copies/cm2 pre-decontamination and 19.2 ± 118 viral copies/cm2 post-decontamination, demonstrating significantly reduced viral surface distribution (p < 0.0001). Conclusions: Environmental sampling is an effective method for evaluating decontamination protocols and validating measures used to contain SARS-CoV-2 viral particles. While chemical decontamination effectively removes detectable viral RNA from surfaces, our approach to droplet/contact containment with an antechamber was not highly effective. These data suggest that hospitals should plan for the potential of aerosolized virions when creating strategies to contain SARS-CoV-2.


Assuntos
COVID-19 , SARS-CoV-2 , Descontaminação , Humanos , Unidades de Terapia Intensiva , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico
13.
Phys Rev Lett ; 125(13): 136602, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-33034493

RESUMO

First-principles calculations of e-ph interactions are becoming a pillar of electronic structure theory. However, the current approach is incomplete. The piezoelectric (PE) e-ph interaction, a long-range scattering mechanism due to acoustic phonons in noncentrosymmetric polar materials, is not accurately described at present. Current calculations include short-range e-ph interactions (obtained by interpolation) and the dipolelike Frölich long-range coupling in polar materials, but lack important quadrupole effects for acoustic modes and PE materials. Here we derive and compute the long-range e-ph interaction due to dynamical quadrupoles, and apply this framework to investigate e-ph interactions and the carrier mobility in the PE material wurtzite GaN. We show that the quadrupole contribution is essential to obtain accurate e-ph matrix elements for acoustic modes and to compute PE scattering. Our work resolves the outstanding problem of correctly computing e-ph interactions for acoustic modes from first principles, and enables studies of e-ph coupling and charge transport in PE materials.

14.
medRxiv ; 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32511486

RESUMO

IMPORTANCE: The novel Coronavirus Disease 2019 (COVID-19), declared a pandemic in March 2020, may present with disproportionately higher rates in underrepresented racial/ethnic minority populations in the United States, including African American communities who have traditionally been over-represented in negative health outcomes. STUDY OBJECTIVE: To understand the impact of the density of African American communities (defined as the percentage of African Americans in a county) on COVID-19 prevalence and death rate within the three most populous counties in each U.S. state and territory (n=152). Design: An ecological study using linear regression was employed for the study. SETTING: The top three most populous counties of each U.S. state and territory were included in analyses for a final sample size of n=152 counties. PARTICIPANTS: Confirmed COVID-19 cases and deaths that were accumulated between January 22, 2020 and April 12, 2020 in each of the three most populous counties in each U.S. state and territory were included. MAIN OUTCOME MEASURES: Linear regression was used to determine the association between African American density and COVID-19 prevalence (defined as the percentage of cases for the county population), and death rate (defined as number of deaths per 100,000 population). The models were adjusted for median age and poverty. RESULTS: There was a direct association between African American density and COVID-19 prevalence; COVID-19 prevalence increased 5% for every 1% increase in county AA density (p<.01). There was also an association between county AA density and COVID-19 deaths, such; the death rate increased 2 per 100,000 for every percentage increase in county AA density (p=.02). CONCLUSION: These study findings indicate that communities with a high African American density have been disproportionately burdened with COVID-19. Further study is needed to indicate if this burden is related to environmental factors or individual factors such as types of employment or comorbidities that members of these community have.

15.
Nat Nanotechnol ; 15(7): 580-584, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32572229

RESUMO

Moiré superlattices in van der Waals heterostructures have given rise to a number of emergent electronic phenomena due to the interplay between atomic structure and electron correlations. Indeed, electrons in these structures have been recently found to exhibit a number of emergent properties that the individual layers themselves do not exhibit. This includes superconductivity1,2, magnetism3, topological edge states4,5, exciton trapping6 and correlated insulator phases7. However, the lack of a straightforward technique to characterize the local structure of moiré superlattices has thus far impeded progress in the field. In this work we describe a simple, room-temperature, ambient method to visualize real-space moiré superlattices with sub-5-nm spatial resolution in a variety of twisted van der Waals heterostructures including, but not limited to, conducting graphene, insulating boron nitride and semiconducting transition metal dichalcogenides. Our method uses piezoresponse force microscopy, an atomic force microscope modality that locally measures electromechanical surface deformation. We find that all moiré superlattices, regardless of whether the constituent layers have inversion symmetry, exhibit a mechanical response to out-of-plane electric fields. This response is closely tied to flexoelectricity wherein electric polarization and electromechanical response is induced through strain gradients present within moiré superlattices. Therefore, moiré superlattices of two-dimensional materials manifest themselves as an interlinked network of polarized domain walls in a non-polar background matrix.

16.
F1000Res ; 82019.
Artigo em Inglês | MEDLINE | ID: mdl-31249674

RESUMO

Cardiac arrest remains a significant cause of death and disability throughout the world. However, as our understanding of cardiac arrest and resuscitation physiology has developed, new technologies are fundamentally altering our potential to improve survival and neurologic sequela. Some advances are relatively simple, requiring only alterations in current basic life support measures or integration with pre-hospital organization, whereas others, such as extra-corporeal membrane oxygenation, require significant time and resource investments. When combined with consistent rescuer and patient-physiologic monitoring, these innovations allow an unprecedented capacity to personalize cardiac arrest resuscitation to patient-specific pathophysiology. However, as more extensive options are established, it can be difficult for providers to incorporate novel resuscitation techniques into a cardiac arrest protocol which can fit a wide variety of cases with varying complexity. This article will explore recent advances in our understanding of cardiac arrest physiology and resuscitation sciences, with particular focus on the metabolic phase after significant ischemia has been induced. To this end, we establish a practical consideration for providers seeking to integrate novel advances in cardiac arrest resuscitation into daily practice.


Assuntos
Reanimação Cardiopulmonar/métodos , Parada Cardíaca/terapia , Humanos , Medicina de Precisão
17.
Cancers (Basel) ; 12(1)2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31888002

RESUMO

Ovarian cancer remains a highly lethal disease due to its late clinical presentation and lack of reliable early biomarkers. Protein-based diagnostic markers have presented limitations in identifying ovarian cancer. We tested the potential of phospholipids as markers of ovarian cancer by utilizing inter-related regulation of phospholipids, a unique property that allows the use of ratios between phospholipid species for quantitation. High-performance liquid chromatography mass spectrometry was used to measure phospholipid, lysophospholipid, and sphingophospholipid content in plasma from patients with benign ovarian masses, patients with ovarian cancer, and controls. We applied both absolute and relative phospholipid ratios for quantitation. Receiver operating characteristic analysis was performed to test the sensitivity and specificity. We found that utilization of ratios between phospholipid species greatly outperformed absolute quantitation in the identification of ovarian cancer. Of the phospholipids analyzed, species in phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and sphingomyelin (SM) were found to have great biomarker potential. LPC(20:4)/LPC(18:0) carried the greatest capacity to differentiate cancer from control, SM(d18:1/24:1)/SM(d18:1/22:0) to differentiate benign from cancer, and PC(18:0/20:4)/PC(18:0/18:1) to differentiate benign from control. These results demonstrate the potential of plasma phospholipids as a novel marker of ovarian cancer by utilizing the unique characteristics of phospholipids to further enhance the diagnostic power.

18.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1093-1094: 147-157, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30029201

RESUMO

Phospholipids content in cellular and mitochondrial membranes is essential for maintaining normal function. Previous studies have found a lower polyunsaturated fatty acid (PUFA) content in mitochondria than whole tissue, theorizing decreased PUFA protects against oxidative injury. However, phospholipids (PPLs) are uniquely difficult to quantify without class separation and, as prior approaches have predominately used reverse-phase HPLC or shotgun analysis, quantitation of PPL classes may have been complicated due to the existence of numerous isobaric and isomeric species. We apply normal-phase HPLC with class separation to compare whole tissue and mitochondrial PPL profiles in rat brain, heart, kidney, and liver. In addition, we establish a novel method to ascertain PPL origin, using cardiolipin as a comparator to establish relative cardiolipin /PPL ratios. We report a higher PUFA content in tissue mitochondria driven by increased phosphatidylcholine unsaturation, suggesting mitochondria purposefully incorporate higher PUFA PPLs.


Assuntos
Ácidos Graxos Insaturados/análise , Membranas Mitocondriais/química , Fosfatidilcolinas/análise , Fosfolipídeos/análise , Animais , Química Encefálica , Cardiolipinas/análise , Cromatografia Líquida de Alta Pressão , Ácidos Graxos Insaturados/química , Rim/química , Fígado/química , Miocárdio/química , Especificidade de Órgãos , Fosfatidilcolinas/química , Fosfolipídeos/química , Ratos
19.
Planta ; 248(3): 613-628, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29846775

RESUMO

MAIN CONCLUSION: The histone acetyltransferase GCN5 and associated transcriptional coactivator ADA2b are required to couple endoreduplication and trichome branching. Mutation of ADA2b also disrupts the relationship between ploidy and leaf cell size. Dynamic chromatin structure has been established as a general mechanism by which gene function is temporally and spatially regulated, but specific chromatin modifier function is less well understood. To address this question, we have investigated the role of the histone acetyltransferase GCN5 and the associated coactivator ADA2b in developmental events in Arabidopsis thaliana. Arabidopsis plants with T-DNA insertions in GCN5 (also known as HAG1) or ADA2b (also known as PROPORZ1) display pleiotropic phenotypes including dwarfism and floral defects affecting fertility. We undertook a detailed characterization of gcn5 and ada2b phenotypic effects in rosette leaves and trichomes to establish a role for epigenetic control in these developmental processes. ADA2b and GCN5 play specific roles in leaf tissue, affecting cell growth and division in rosette leaves often in complex and even opposite directions. Leaves of gcn5 plants display overall reduced ploidy levels, while ada2b-1 leaves show increased ploidy. Endoreduplication leading to increased ploidy is also known to contribute to normal trichome morphogenesis. We demonstrate that gcn5 and ada2b mutants display alterations in the number and patterning of trichome branches, with ada2b-1 and gcn5-1 trichomes being significantly less branched, while gcn5-6 trichomes show increased branching. Elongation of the trichome stalk and branches also vary in different mutant backgrounds, with stalk length having an inverse relationship with branch number. Taken together, our data indicate that, in Arabidopsis, leaves and trichomes ADA2b and GCN5 are required to couple nuclear content with cell growth and morphogenesis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Histona Acetiltransferases/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Fatores de Transcrição/metabolismo , Tricomas/crescimento & desenvolvimento , Arabidopsis/enzimologia , Arabidopsis/genética , Arabidopsis/metabolismo , Citometria de Fluxo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Microscopia de Interferência , Ploidias , Reação em Cadeia da Polimerase
20.
Instr Course Lect ; 66: 25-37, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28594486

RESUMO

Traumatic injury to the foot and ankle can result in long-term disability, which may have substantial negative implications on a patient's functional outcomes and quality of life. The diagnosis and appropriate management of these challenging injuries are not always agreed on or straightforward. In particular, the appropriate diagnosis and management of distal tibiofibular syndesmotic injuries as well as the surgical approach and role of primary subtalar arthrodesis for intra-articular calcaneal fractures are controversial.


Assuntos
Traumatismos do Tornozelo , Calcâneo , Fraturas Ósseas , Traumatismos do Tornozelo/cirurgia , Artrodese , Calcâneo/lesões , Fixação Interna de Fraturas , Fraturas Ósseas/cirurgia , Humanos , Qualidade de Vida , Resultado do Tratamento
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