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1.
Nature ; 625(7994): 264-269, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38093009

RESUMEN

Spin nematic is a magnetic analogue of classical liquid crystals, a fourth state of matter exhibiting characteristics of both liquid and solid1,2. Particularly intriguing is a valence-bond spin nematic3-5, in which spins are quantum entangled to form a multipolar order without breaking time-reversal symmetry, but its unambiguous experimental realization remains elusive. Here we establish a spin nematic phase in the square-lattice iridate Sr2IrO4, which approximately realizes a pseudospin one-half Heisenberg antiferromagnet in the strong spin-orbit coupling limit6-9. Upon cooling, the transition into the spin nematic phase at TC ≈ 263 K is marked by a divergence in the static spin quadrupole susceptibility extracted from our Raman spectra and concomitant emergence of a collective mode associated with the spontaneous breaking of rotational symmetries. The quadrupolar order persists in the antiferromagnetic phase below TN ≈ 230 K and becomes directly observable through its interference with the antiferromagnetic order in resonant X-ray diffraction, which allows us to uniquely determine its spatial structure. Further, we find using resonant inelastic X-ray scattering a complete breakdown of coherent magnon excitations at short-wavelength scales, suggesting a many-body quantum entanglement in the antiferromagnetic state10,11. Taken together, our results reveal a quantum order underlying the Néel antiferromagnet that is widely believed to be intimately connected to the mechanism of high-temperature superconductivity12,13.

2.
Nano Lett ; 24(4): 1277-1283, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38232182

RESUMEN

We reveal the critical effect of ultrashort dephasing on the polarization of high harmonic generation in Dirac fermions. As the elliptically polarized laser pulse falls in or slightly beyond the multiphoton regime, the elliptically polarized high harmonic generation is produced and exhibits a characteristic polarimetry of the polarization ellipse, which is found to depend on the decoherence time T2. T2 could then be determined to be a few femtoseconds directly from the experimentally observed polarimetry of high harmonics. This shows a sharp contrast with the semimetal regime of higher pump intensity, where the polarimetry is irrelevant to T2. An access to the dephasing dynamics would extend the prospect of high harmonic generation into the metrology of a femtosecond dynamic process in the coherent quantum control.

3.
J Endocrinol Invest ; 47(10): 2551-2563, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38493245

RESUMEN

BACKGROUND: Menopause, a dramatical estrogen-deficient condition, is considered the most significant milestone in women's health. PURPOSE: To investigate the metabolite changes attributed to estrogen deficiency using random forest (RF)-based machine learning (ML) modeling strategy in ovariectomized (OVX) mice as well as determine the clinical relevance of selected metabolites in older women. METHODS AND RESULTS: Untargeted and targeted metabolomic analyses revealed that metabolites related to TCA cycle, sphingolipids, phospholipids, fatty acids, and amino acids, were significantly changed in the plasma and/or muscle of OVX mice. Subsequent ML classifiers based on RF algorithm selected alpha-ketoglutarate (AKG), arginine, carnosine, ceramide C24, phosphatidylcholine (PC) aa C36:6, and PC ae C42:3 in plasma as well as PC aa 34:1, PC aa C34:3, PC aa C36:5, PC aa C32:1, PC aa C36:2, and sphingosine in muscle as top featured metabolites that differentiate the OVX mice from the sham-operated group. When circulating levels of AKG, arginine, and carnosine, which showed the most significant changes in OVX mice blood, were measured in postmenopausal women, higher plasma AKG levels were associated with lower bone mass, weak grip strength, poor physical performance, and increased frailty risk. CONCLUSIONS: Metabolomics- and ML-based methods identified the key metabolites of blood and muscle that were significantly changed after ovariectomy in mice, and the clinical implication of several metabolites was investigated by looking at their correlation with body composition and frailty-related parameters in postmenopausal women. These findings provide crucial context for understanding the diverse physiological alterations caused by estrogen deficiency in women.


Asunto(s)
Composición Corporal , Fragilidad , Metabolómica , Ovariectomía , Posmenopausia , Femenino , Animales , Ratones , Humanos , Posmenopausia/metabolismo , Composición Corporal/fisiología , Metabolómica/métodos , Fragilidad/metabolismo , Fragilidad/sangre , Persona de Mediana Edad , Anciano , Metaboloma/fisiología , Biomarcadores/sangre , Ratones Endogámicos C57BL , Aprendizaje Automático
4.
Neurosurg Rev ; 47(1): 30, 2024 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-38172487

RESUMEN

Pneumocephalus is the pathologic collection of air in the intracranial cavity. In sufficient volumes, it can contribute to symptoms ranging from headaches to death. For conservative treatment, oxygen use is commonplace. Although this is an accepted tenet of clinical practice, it is not necessarily founded on robust trials. An electronic search of databases EMBASE and MEDLINE and the Cochrane Library was undertaken as per the 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. Three articles were included. Although the modes of oxygen delivery were heterogenous (non-rebreather versus endotracheal versus hyperbaric chamber), all studies concluded favorably on the use of oxygen therapy for increased reabsorption of pneumocephalus.


Asunto(s)
Neumocéfalo , Humanos , Neumocéfalo/terapia , Cefalea , Oxígeno
5.
J Synchrotron Radiat ; 30(Pt 3): 643-649, 2023 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-36947164

RESUMEN

An endstation for resonant inelastic X-ray scattering (RIXS), dedicated to operations in the hard X-ray regime, has been constructed at the 1C beamline of Pohang Light Source II. At the Ir L3-edge, a total energy resolution of 34.2 meV was achieved, close to the theoretical estimation of 34.0 meV, which considers factors such as the incident energy bandpass, intrinsic analyzer resolution, geometrical broadening of the spectrometer, finite beam-size effect and Johann aberration. The performance of the RIXS instrument is demonstrated by measuring the RIXS spectra of Sr2IrO4. The endstation can be easily reconfigured to measure energy-integrated intensities with very low background for diffuse scattering and diffraction experiments.

6.
Neuroradiology ; 64(5): 897-903, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34704112

RESUMEN

PURPOSE: Cortical vein opacification is not routinely assessed in patients presenting with acute ischemic stroke (AIS), and the value of temporal assessment of venous outflow is not known. We evaluated the utility of assessing cortical venous drainage over time using multiphase CT angiography (mCTA). METHODS: Cortical venous drainage was assessed in patients from the Precise and Rapid Assessment of Collaterals Using Multi-Phase CTA in the Triage of Patients With Acute Ischemic Stroke for IA Therapy prospective multicenter cohort study of patients with symptoms of AIS with ICA and/or middle cerebral artery occlusion on baseline mCTA. Opacification of vein of Labbe, sphenoparietal sinus, superficial middle cerebral vein, and vein of Trolard of the affected hemisphere was graded as no (0), partial (1), or full (2) opacification in each mCTA phase. The venous opacification scores for each phase were added to generate a total venous score (TVS) (range 0-24). Primary outcome was 90-day modified Rankin score. Repeated measures analysis was used to assess the effect of phase timing on venous score on outcome. RESULTS: Of 432 patients, 284 (65.7%) had proximal arterial occlusions. Median venous opacification score per phase (range 0-8) was 3 (IQR 1-6) in the first phase and increased in the second and third phases [median (IQR): 6 (5-8) and 8 (6-8), respectively] of the mCTA. In a multivariable analysis adjusting for age, baseline National Institutes of Health Stroke Scale, and Alberta stroke program early CT score, a significant association between TVS and 90-day mRS was noted ([adjusted cOR for TVS 6-11: 0.16 (95% CI 0.05-0.51); TVS 12-17: 0.18 (95% CI 0.06-0.57); TVS 18-24: 0.20 (0.06-0.63)]. Repeated measures analysis of venous scores from all three phases showed a significant effect of time/phase on TVS (p < 0.001). CONCLUSION: This study concludes that venous opacification over time on multiphase CTA is associated with 90-day clinical outcome. There was however no added benefit of venous scoring vis-a-vis arterial collateral assessment in predicting outcome.


Asunto(s)
Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Isquemia Encefálica/diagnóstico por imagen , Angiografía Cerebral , Estudios de Cohortes , Angiografía por Tomografía Computarizada , Drenaje , Humanos , Estudios Prospectivos , Estudios Retrospectivos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/terapia
7.
J Eur Acad Dermatol Venereol ; 36(5): 651-660, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35098589

RESUMEN

Nail melanoma (NM) is an important differential diagnosis in patients with longitudinal melanonychia. However, diagnosis is often challenging as it is difficult to differentiate from other pigmented nail disorders. The main challenge for diagnosis is obtaining adequate nail matrix biopsy specimens for histopathological assessment. Furthermore, the histopathological changes in the early stages of NM are subtle and contribute to a delay in diagnosis and care. Therefore, the integration of clinical and histopathological analyses is essential. Clinical and dermoscopic features, such as a broadened width of asymmetric bands in an irregular pattern, with multicolour pigmentation, periungual pigmentation, and continuous growth, are features that support the diagnosis of NM. The essential histological features that must be assessed are cellular morphology, architectural features, melanocyte density, and inflammatory changes. The reported mutations in NMs were BRAF (0-43%), NRAS (0-31%), KIT (0-50%), NF1 (0-50%), and GNAQ (0-25%). Surgery is the primary treatment for NM. The recommended treatment for in situ or minimally invasive NM is functional surgery, but cases with suspected bone invasion should be treated with amputation. Targeted therapy and immunotherapy are indicated for advanced stages of NM. This review summarizes the updated guidelines for the diagnosis and treatment of NM.


Asunto(s)
Melanoma , Enfermedades de la Uña , Neoplasias Cutáneas , Dermoscopía , Diagnóstico Diferencial , Humanos , Melanoma/diagnóstico , Melanoma/genética , Melanoma/terapia , Enfermedades de la Uña/diagnóstico , Enfermedades de la Uña/genética , Enfermedades de la Uña/terapia , Uñas/patología , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/terapia
9.
Nat Mater ; 19(9): 974-979, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32632280

RESUMEN

Td-WTe2 (non-centrosymmetric and orthorhombic), a type-II Weyl semimetal, is expected to have higher-order topological phases with topologically protected, helical one-dimensional hinge states when its Weyl points are annihilated. However, the detection of these hinge states is difficult due to the semimetallic behaviour of the bulk. In this study, we have spatially resolved the hinge states by analysing the magnetic field interference of the supercurrent in Nb-WTe2-Nb proximity Josephson junctions. The Josephson current along the a axis of the WTe2 crystal, but not along the b axis, showed a sharp enhancement at the edges of the junction, and the amount of enhanced Josephson current was comparable to the upper limits of a single one-dimensional helical channel. Our experimental observations suggest a higher-order topological phase in WTe2 and its corresponding anisotropic topological hinge states, in agreement with theoretical calculations. Our work paves the way for the study of hinge states in topological transition-metal dichalcogenides and analogous phases.

10.
Clin Exp Dermatol ; 46(5): 901-905, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33763910

RESUMEN

Skin necrosis is one of the most severe complications following filler injections, and can result in permanent aesthetic defects. Although an increasing number of studies have addressed the management of dermal filler complications, no study has described the spectrum of microbial pathogens. The aim of this study was to delineate the bacterial profile and prognostic factors of filler-related skin necrosis by reviewing the clinical and microbiological features of these patients. A retrospective medical record review of patients undergoing treatment for skin necrosis induced by fillers was conducted. In total, 10 cases were identified, with injection sites being the nasolabial fold (70%; n = 7), nasal dorsum (20%; n = 2) and nasal tip (10%; n = 1). Reviewing the culture results, the true culture-positive rate was found to be 50% after cases of contamination were excluded. To avoid permanent sequelae, all physicians should be aware of possible secondary infections when treating filler-induced skin necrosis.


Asunto(s)
Rellenos Dérmicos/efectos adversos , Necrosis/inducido químicamente , Necrosis/microbiología , Enfermedades de la Piel/etiología , Adulto , Antibacterianos/normas , Antibacterianos/uso terapéutico , Técnicas de Cultivo/métodos , Técnicas de Cultivo/estadística & datos numéricos , Rellenos Dérmicos/administración & dosificación , Femenino , Bacterias Gramnegativas/crecimiento & desarrollo , Bacterias Gramnegativas/aislamiento & purificación , Humanos , Reacción en el Punto de Inyección/microbiología , Reacción en el Punto de Inyección/patología , Persona de Mediana Edad , Surco Nasolabial/microbiología , Surco Nasolabial/patología , Necrosis/diagnóstico , Necrosis/terapia , Nariz/microbiología , Nariz/patología , Pronóstico , Repitelización/fisiología , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Enfermedades de la Piel/patología
11.
Clin Exp Dermatol ; 46(2): 324-327, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32974941

RESUMEN

Systemic contact dermatitis (SCD) develops when a person who was previously sensitized to an allergen is exposed to the same allergen via the systemic route. In East Asia, the use of lacquer for polishing furniture is common and a part of the traditional culture. Contact exposure to tableware polished with Rhus lacquer may lead to sensitization. In Korea, SCD is commonly observed after systemic exposure to Rhus, a nutritious food item consumed because of the common belief of it improving the immune system. In this study, we reviewed the medical records of 21 Korean patients with SCD caused by Rhus ingestion. We found that the most significant epidemiological factor for SCD was the season of the year. Furthermore, 66.67% of the patients presented with leucocytosis and 23.81% showed increased liver enzyme levels. It is important to educate people on the risks associated with the systemic ingestion of Rhus.


Asunto(s)
Dermatitis por Contacto/etiología , Dermatitis por Toxicodendron/diagnóstico , Exposición Dietética/efectos adversos , Rhus/efectos adversos , Corticoesteroides/uso terapéutico , Adulto , Anciano , Alérgenos/inmunología , Dermatitis por Toxicodendron/tratamiento farmacológico , Dermatitis por Toxicodendron/epidemiología , Dermatitis por Toxicodendron/inmunología , Dieta Vegetariana/efectos adversos , Quimioterapia Combinada , Femenino , Antagonistas de los Receptores Histamínicos/uso terapéutico , Humanos , Incidencia , Masculino , Persona de Mediana Edad , República de Corea , Estudios Retrospectivos , Rhus/inmunología , Estaciones del Año
12.
J Eur Acad Dermatol Venereol ; 35(7): 1587-1594, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33721365

RESUMEN

BACKGROUND: Letibotulinum toxin A (LeBA) was approved by the Ministry of Food and Drug Safety (known as the Korea Food & Drug Administration) for cosmetic indications in 2012. However, the efficacy and safety of this newly introduced LeBA have not been investigated in crow's feet lines (CFL) treatment and standardization before its universal use. OBJECTIVE: The aim of this multicentre, double-blind, randomized, parallel, active-controlled Phase III clinical trial with two stages (ClinicalTrials.gov identifier: NCT03408236) was to investigate the non-inferiority of LeBA vs. the existing onabotulinum toxin A (OnBA) for the treatment of CFL. METHODS: A total of 240 subjects were randomized to either the test (LeBA) or control (OnBA) group. At the baseline and at weeks 4 while maximum smiling (primary efficacy assessment), 8, 12 and 16, investigator's on-site evaluation, independent evaluator, evaluation by the subjects, subjects' satisfaction assessment and safety assessment were performed. RESULTS: At week 4, the response rate of primary efficacy assessment was 69.75% and 68.33% in the test (LeBA) and control (OnBA) groups, respectively, without a significant difference. Other minor secondary evaluation results showed significant differences suggesting that LeBA offered better improvement than OnBA, but the overall results did not show significant differences between the two groups. CONCLUSION: This study showed that LeBA was as effective and safe as OnBA for the treatment of CFL at the same doses.


Asunto(s)
Toxinas Botulínicas Tipo A , Fármacos Neuromusculares , Envejecimiento de la Piel , Toxinas Botulínicas Tipo A/efectos adversos , Método Doble Ciego , República de Corea , Resultado del Tratamiento
13.
J Synchrotron Radiat ; 27(Pt 4): 963-969, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33566005

RESUMEN

Resonant inelastic X-ray scattering (RIXS) is increasingly playing a significant role in studying highly correlated systems, especially since it was proven capable of measuring low-energy magnetic excitations. However, despite high expectations for experimental evidence of novel magnetic phases at high pressure, unequivocal low-energy spectral signatures remain obscured by extrinsic scattering from material surrounding the sample in a diamond anvil cell (DAC): pressure media, Be gasket and the diamond anvils themselves. A scattered X-ray collimation based medium-energy resolution (∼100 meV) analyzer system for a RIXS spectrometer at the Ir L3-absorption edge has been designed and built to remediate these difficulties. Due to the confocal nature of the analyzer system, the majority of extrinsic scattering is rejected, yielding a clean low-energy excitation spectrum of an iridate Sr2IrO4 sample in a DAC cell. Furthermore, the energy resolution of different configurations of the collimating and analyzing optics are discussed.

14.
Nat Mater ; 18(6): 563-567, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30911120

RESUMEN

Ruthenium compounds serve as a platform for fundamental concepts such as spin-triplet superconductivity1, Kitaev spin liquids2-5 and solid-state analogues of the Higgs mode in particle physics6,7. However, basic questions about the electronic structure of ruthenates remain unanswered, because several key parameters (including Hund's coupling, spin-orbit coupling and exchange interactions) are comparable in magnitude and their interplay is poorly understood, partly due to difficulties in synthesizing large single crystals for spectroscopic experiments. Here we introduce a resonant inelastic X-ray scattering (RIXS)8,9 technique capable of probing collective modes in microcrystals of 4d electron materials. We observe spin waves and spin-state transitions in the honeycomb antiferromagnet SrRu2O6 (ref. 10) and use the extracted exchange interactions and measured magnon gap to explain its high Néel temperature11-16. We expect that the RIXS method presented here will enable momentum-resolved spectroscopy of a large class of 4d transition-metal compounds.

15.
Phys Rev Lett ; 124(6): 067201, 2020 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-32109088

RESUMEN

The effect of compression on the magnetic ground state of Sr_{2}IrO_{4} is studied with x-ray resonant techniques in the diamond anvil cell. The weak interlayer exchange coupling between square-planar 2D IrO_{2} layers is readily modified upon compression, with a crossover between magnetic structures around 7 GPa mimicking the effect of an applied magnetic field at ambient pressure. Higher pressures drive an order-disorder magnetic phase transition with no magnetic order detected above 17-20 GPa. The persistence of strong exchange interactions between J_{eff}=1/2 magnetic moments within the insulating IrO_{2} layers up to at least 35 GPa points to a highly frustrated magnetic state in compressed Sr_{2}IrO_{4}, opening the door for realization of novel quantum paramagnetic phases driven by extended 5d orbitals with entangled spin and orbital degrees of freedom.

16.
Eur J Neurol ; 27(5): 900-902, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32064742

RESUMEN

BACKGROUND AND PURPOSE: We analyzed the incidence and causes of oral anticoagulant (OAC) cessation and subsequent stroke after OAC withdrawal in a cohort of Korean stroke patients with atrial fibrillation. METHODS: The Korean Atrial Fibrillation Evaluation Registry in Ischemic Stroke patients (K-ATTENTION) is a multicenter cohort study, merging stroke registries from 11 tertiary centers in Korea. The number of OAC interruption episodes and the reasons were reviewed from hospital records. Stroke after OAC withdrawal was defined when a patient experienced ischaemic stroke within 31 days after OAC withdrawal. Clinical variables were compared between patients who experienced stroke recurrence during OAC interruption and those who did not experience recurrence. RESULTS: Among 3213 stroke patients with atrial fibrillation, a total of 329 episodes of OAC interruption were detected in 229 patients after index stroke (mean age 72.9 ± 8.3 years, 113 female patients). The most frequent reason for OAC withdrawal was poor compliance [103 episodes (31.3%)] followed by extracranial bleeding [96 episodes (29.2%)]. Stroke after OAC withdrawal was noted in 13 patients. Mean age, vascular risk factor profile and mean CHA2 DS2 -VASc score were not significantly different between patients with and without recurrent stroke. CONCLUSIONS: A considerable number of stroke patients with atrial fibrillation experienced temporary interruption of OAC after index stroke, which was associated with stroke recurrence of 4.0 cases per 100 interruption episodes.


Asunto(s)
Fibrilación Atrial , Isquemia Encefálica , Accidente Cerebrovascular , Administración Oral , Anciano , Anciano de 80 o más Años , Anticoagulantes/uso terapéutico , Fibrilación Atrial/complicaciones , Fibrilación Atrial/tratamiento farmacológico , Fibrilación Atrial/epidemiología , Isquemia Encefálica/complicaciones , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/epidemiología , Estudios de Cohortes , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Sistema de Registros , República de Corea/epidemiología , Medición de Riesgo , Factores de Riesgo , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/tratamiento farmacológico , Accidente Cerebrovascular/epidemiología
17.
Eur J Neurol ; 27(2): 343-351, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31535427

RESUMEN

BACKGROUND AND PURPOSE: The rate at which the chance of a good outcome of endovascular stroke therapy (EVT) decays with time when eligible patients are selected by baseline diffusion-weighted magnetic resonance imaging (DWI-MRI) and whether ischaemic core size affects this rate remain to be investigated. METHODS: This study analyses a prospective multicentre registry of stroke patients treated with EVT based on pretreatment DWI-MRI that was categorized into three groups: small [Diffusion-Weighted Imaging Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS)] (8-10), moderate (5-7) and large (<5) cores. The main outcome was a good outcome at 90 days (modified Rankin Scale 0-2). The interaction between onset-to-groin puncture time (OTP) and DWI-ASPECTS categories regarding functional outcomes was investigated. RESULTS: Ultimately, 985 patients (age 69 ± 11 years; male 55%) were analysed. Potential interaction effects between the DWI-ASPECTS categories and OTP on a good outcome at 90 days were observed (Pinteraction  = 0.06). Every 60-min delay in OTP was associated with a 16% reduced likelihood of a good outcome at 90 days amongst patients with large cores, although no associations were observed amongst patients with small to moderate cores. Interestingly, the adjusted rates of a good outcome at 90 days steeply declined between 65 and 213 min of OTP and then remained smooth throughout 24 h of OTP (Pnonlinearity  = 0.15). CONCLUSIONS: Our study showed that the probability of a good outcome after EVT nonlinearly decreased, with a steeper decline at earlier OTP than at later OTP. Discrepant effects of OTP on functional outcomes by baseline DWI-ASPECTS categories were observed. Thus, different strategies for EVT based on time and ischaemic core size are warranted.


Asunto(s)
Accidente Cerebrovascular , Anciano , Anciano de 80 o más Años , Alberta , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/terapia , Imagen de Difusión por Resonancia Magnética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/terapia , Tiempo de Tratamiento , Resultado del Tratamiento
18.
Osteoarthritis Cartilage ; 27(10): 1508-1517, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31229684

RESUMEN

OBJECTIVE: Osteoarthritis (OA) is characterized by cartilage degeneration resulting from hypertrophic changes in chondrocytes caused by altered gene expression. The involvement of Ras homolog enriched in brain (RHEB) in OA regulation is unclear. METHODS: Human knee articular cartilage samples - were analyzed for structural and biological changes by histology, immunohistochemistry, real time PCR and western blotting. OA-mouse model developed by surgical destabilization of the medial meniscus (DMM) were treated with adenovirus harboring Rheb gene to analyze onset and progression of OA. Histological scoring, immunohistochemistry, and TUNEL assay was performed to assess cartilage damage across the entire joint. RESULTS: Human and mouse OA cartilage is degenerated and has markedly reduced levels of RHEB. Human OA-degenerated chondrocytes (DC) exhibited a fibroblastic phenotype and 80 % of degenerative cartilage were senescent, with higher levels of reactive oxygen species (ROS). Gene expression analysis of DC revealed almost no COL2A1 expression and reduced SOX9 and RHEB expression. Transient transfection of RHEB rescued the DC phenotype and reduced senescence and ROS levels markedly. RHEB overexpression also increased COL2A1 and SOX9 expression. In an OA-mouse model, the Rheb protein level decreased as the severity of OA increased. Ectopic expression of Rheb using adenovirus in mouse-OA cartilage suppressed surgically-induced OA pathogenesis accompanied by modulation of Adamts5, Mmp 13, Col 10, and Col2a1 expression. Rheb induction significantly reduced apoptosis in OA-cartilage. CONCLUSION: RHEB plays an important role in maintaining the chondrogenic characteristics of chondrocytes, and has potential in preventing progression of OA in the destabilize the medial meniscus (DMM) mouse model of OA.


Asunto(s)
Cartílago Articular/fisiología , Condrogénesis , Terapia Genética , Osteoartritis/genética , Osteoartritis/terapia , Proteína Homóloga de Ras Enriquecida en el Cerebro/genética , Animales , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Osteoartritis/prevención & control
19.
Osteoporos Int ; 30(5): 1059-1069, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30719548

RESUMEN

Analyses using the largest Korean cohort of adrenal incidentaloma (AI) revealed that subtle cortisol excess in premenopausal women and reduced dehydroepiandrosterone-sulfate (DHEA-S) in postmenopausal women and men are associated with bone mineral density (BMD) reduction in Asian patients with subclinical hypercortisolism (SH). INTRODUCTION: Few studies evaluated bone metabolism in Asians with SH. We investigated associations of cortisol and DHEA-S, an adrenal androgen, with BMD in Asians with AI, with or without SH. METHODS: We used cross-sectional data of a prospective multicenter study from Korea. We measured BMD, bone turnover markers, cortisol levels after 1-mg dexamethasone suppression test (1-mg DST), DHEA-S, and baseline cortisol to DHEA-S ratio (cort/DHEA-S) in 109 AI patients with SH (18 premenopausal, 38 postmenopausal women, and 53 men) and 686 with non-functional AI (NFAI; 59 premenopausal, 199 postmenopausal women, and 428 men). RESULTS: Pre- and postmenopausal women, but not men, with SH had lower BMDs at lumbar spine (LS) than those with NFAI (P = 0.008~0.016). Premenopausal women with SH also had lower BMDs at the hip than those with NFAI (P = 0.009~0.012). After adjusting for confounders, cortisol levels after 1-mg DST demonstrated inverse associations with BMDs at all skeletal sites only in premenopausal women (ß = - 0.042~- 0.033, P = 0.019~0.040). DHEA-S had positive associations with LS BMD in postmenopausal women (ß = 0.096, P = 0.001) and men (ß = 0.029, P = 0.038). The cort/DHEA-S had inverse associations with LS BMD in postmenopausal women (ß = - 0.081, P = 0.004) and men (ß = - 0.029, P = 0.011). These inverse associations of cort/DHEA-S remained significant after adjusting for cortisol levels after 1-mg DST (ß = - 0.079~- 0.026, P = 0.006~0.029). In postmenopausal women, the odds ratios of lower BMD by DHEA-S and cort/DHEA-S was 0.26 (95% CI, 0.08-0.82) and 3.40 (95% CI, 1.12-10.33), respectively. CONCLUSION: Subtle cortisol excess in premenopausal women and reduced DHEA-S in postmenopausal women and men may contribute to BMD reduction in Asians with SH.


Asunto(s)
Neoplasias de las Glándulas Suprarrenales/sangre , Densidad Ósea/fisiología , Síndrome de Cushing/sangre , Sulfato de Deshidroepiandrosterona/sangre , Hidrocortisona/sangre , Neoplasias de las Glándulas Suprarrenales/fisiopatología , Adulto , Anciano , Biomarcadores/sangre , Remodelación Ósea/fisiología , Estudios Transversales , Síndrome de Cushing/fisiopatología , Femenino , Cuello Femoral/fisiopatología , Humanos , Hidrocortisona/fisiología , Hallazgos Incidentales , Vértebras Lumbares/fisiopatología , Masculino , Persona de Mediana Edad , Osteoporosis/sangre , Osteoporosis/fisiopatología , Posmenopausia/sangre , Posmenopausia/fisiología , Premenopausia/sangre , Premenopausia/fisiología
20.
Osteoporos Int ; 30(5): 1071-1078, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30719549

RESUMEN

The plasma n-3 fatty acid level was 26.2% lower in patients with osteoporotic hip fracture than in those with osteoarthritis. In all patients, n-3 fatty acid was positively associated with bone mineral density and inversely associated with tartrate-resistant acid phosphatase-5b level in bone marrow aspirates, reflecting the bone microenvironment. INTRODUCTION: Despite the potential beneficial role of n-3 fatty acid (FA) on bone metabolism, the specific mechanisms underlying these effects in humans remain unclear. Here, we assessed whether the plasma n-3 level, as an objective indicator of its status, is associated with osteoporosis-related phenotypes and bone-related markers in human bone marrow (BM) samples. METHODS: This was a case-control and cross-sectional study conducted in a clinical unit. n-3 FA in the blood and bone biochemical markers in the BM aspirates were measured by gas chromatography/mass spectrometry and immunoassay, respectively. BM fluids were collected from 72 patients who underwent hip surgery because of either osteoporotic hip fracture (HF; n = 28) or osteoarthritis (n = 44). RESULTS: After adjusting for confounders, patients with HF had 26.2% lower plasma n-3 levels than those with osteoarthritis (P = 0.006), and each standard deviation increment in plasma n-3 was associated with a multivariate-adjusted odds ratio of 0.40 for osteoporotic HF (P = 0.010). In multivariate analyses including all patients, a higher plasma n-3 level was associated with higher bone mass at the lumbar spine (ß = 0.615, P = 0.002) and total femur (ß = 0.244, P = 0.045). Interestingly, the plasma n-3 level was inversely associated with the tartrate-resistant acid phosphatase-5b level (ß = - 0.633, P = 0.023), but not with the bone-specific alkaline phosphatase level, in BM aspirates. CONCLUSIONS: These findings provide clinical evidence that n-3 FA is a potential inhibitor of osteoclastogenesis that favors human bone health.


Asunto(s)
Densidad Ósea/fisiología , Ácidos Grasos Omega-3/sangre , Fracturas de Cadera/fisiopatología , Fracturas Osteoporóticas/fisiopatología , Fosfatasa Ácida Tartratorresistente/metabolismo , Anciano , Anciano de 80 o más Años , Médula Ósea/metabolismo , Resorción Ósea/fisiopatología , Estudios de Casos y Controles , Estudios Transversales , Ácidos Grasos Omega-3/fisiología , Ácidos Grasos Omega-6/sangre , Femenino , Fémur/fisiopatología , Fracturas de Cadera/sangre , Humanos , Vértebras Lumbares/fisiopatología , Masculino , Fracturas Osteoporóticas/sangre
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