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1.
Cell Stem Cell ; 31(4): 554-569.e17, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38579685

RESUMO

The YAP/Hippo pathway is an organ growth and size regulation rheostat safeguarding multiple tissue stem cell compartments. LATS kinases phosphorylate and thereby inactivate YAP, thus representing a potential direct drug target for promoting tissue regeneration. Here, we report the identification and characterization of the selective small-molecule LATS kinase inhibitor NIBR-LTSi. NIBR-LTSi activates YAP signaling, shows good oral bioavailability, and expands organoids derived from several mouse and human tissues. In tissue stem cells, NIBR-LTSi promotes proliferation, maintains stemness, and blocks differentiation in vitro and in vivo. NIBR-LTSi accelerates liver regeneration following extended hepatectomy in mice. However, increased proliferation and cell dedifferentiation in multiple organs prevent prolonged systemic LATS inhibition, thus limiting potential therapeutic benefit. Together, we report a selective LATS kinase inhibitor agonizing YAP signaling and promoting tissue regeneration in vitro and in vivo, enabling future research on the regenerative potential of the YAP/Hippo pathway.


Assuntos
Inibidores de Proteínas Quinases , Proteínas Serina-Treonina Quinases , Proteínas de Sinalização YAP , Animais , Humanos , Camundongos , Proliferação de Células , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Células-Tronco/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Sinalização YAP/agonistas , Proteínas de Sinalização YAP/efeitos dos fármacos , Proteínas de Sinalização YAP/metabolismo , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia
2.
Artigo em Inglês | MEDLINE | ID: mdl-38261479

RESUMO

Integrating information from vision and language modalities has sparked interesting applications in the fields of computer vision and natural language processing. Existing methods, though promising in tasks like image captioning and visual question answering, face challenges in understanding real-life issues and offering step-by-step solutions. In particular, they typically limit their scope to solutions with a sequential structure, thus ignoring complex inter-step dependencies. To bridge this gap, we propose a graph-based approach to vision-language problem solving. It leverages a novel integrated attention mechanism that jointly considers the importance of features within each step as well as across multiple steps. Together with a graph neural network method, this attention mechanism can be progressively learned to predict sequential and non-sequential solution graphs depending on the characterization of the problem-solving process. To tightly couple attention with the problem-solving procedure, we further design new learning objectives with attention metrics that quantify this integrated attention, which better aligns visual and language information within steps, and more accurately captures information flow between steps. Experimental results on VisualHow, a comprehensive dataset of varying solution structures, show significant improvements in predicting steps and dependencies, demonstrating the effectiveness of our approach in tackling various vision-language problems.

3.
Mater Horiz ; 11(3): 862, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38099608

RESUMO

Correction for 'Superprotonic conductivity in RbH2-3y(PO4)1-y: a phosphate deficient analog to cubic CsH2PO4 in the (1 - x)RbH2PO4 - xRb2HPO4 system' by Grace Xiong et al., Mater. Horiz., 2023, 10, 5555-5563, https://doi.org/10.1039/D3MH00852E.

4.
Mater Horiz ; 10(12): 5555-5563, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-37855817

RESUMO

In contrast to CsH2PO4 (cesium dihydrogen phosphate, CDP), a material with a well-established superprotonic transition to a high conductivity state at 228 °C, RbH2PO4 (rubidium dihydrogen phosphate, RDP) decomposes upon heating under ambient pressure conditions. Here we find, from study of the (1 - x)RbH2PO4 - xRb2HPO4 system, the remarkable occurrence of cubic, off-stoichiometric RbH2-3y(PO4)1-y, or α-RDP, with a variable Rb : PO4 ratio. Materials were characterized by simultaneous thermal analysis and in situ X-ray powder diffraction performed under high steam partial pressure, from which the phase diagram between RbH2PO4 (x = 0) and Rb5H7(PO4)4 (x = 1/4) was established. The system displays eutectoid behavior, with a eutectoid transition temperature of 242.0 ± 0.5 °C and eutectoid composition of x = 0.190 ± 0.004. Even the end-member Rb5H7(PO4)4 appears to transform to α-RDP, implying y in the chemical formula of 0.2 and a phosphate site vacancy concentration as high as 20%. Charge balance is attained by a decrease in the average number of protons on the remaining phosphate groups. The cubic lattice parameter at x = 0.180, near the eutectoid composition, and at a temperature of 249 °C is 4.7138(2) Å. This value is substantially smaller than the estimated ambient-pressure lattice parameter of stoichiometric RbH2PO4 of 4.837(12) Å, consistent with the proposal of phosphate site vacancies in the former. The superprotonic conductivity of the x = 0.180 material is 6 × 10-3 S cm-1 at 244 °C, a factor of three lower than that of CDP at the same temperature. While the engineering properties of α-RDP do not suggest immediate technological relevance, the discovery of a superprotonic solid acid with a high concentration of phosphate site vacancies opens new avenues for developing proton conducting electrolytes, and in particular, for controlling their transition behavior.

5.
Oncoimmunology ; 12(1): 2214478, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37284696

RESUMO

The use of immune checkpoint inhibitors (ICIs) targeting PD-L1/PD-1 and CTLA-4 has transformed the oncology practice of hepatocellular carcinoma. However, only 25-30% of the patients with advanced HCC treated with atezolizumab-bevacizumab or tremelimumab-durvalumab (STRIDE) respond initially, and mechanistic biomarkers and novel treatment strategies are urgently needed for patients who present with or acquire resistance to first-line ICI-based therapies. The recent approval of the STRIDE regimen has also engendered new questions, such as patient selection factors (e.g. portal hypertension and history of variceal bleed) and biomarkers, and the optimal combination and sequencing of ICI-based regimens. Triumphs in the setting of advanced HCC have also galvanized considerable interest in the broader application of ICIs to early- and intermediate-stage diseases, including clinical combination of ICIs with locoregional therapies. Among these clinical contexts, the role of ICIs in liver transplantation - which is a potentially curative strategy unique to HCC management - as a bridge to liver transplant in potential candidates or in the setting of post-transplant recurrence, warrants investigation in view of the notable theoretical risk of allograft rejection. In this review, we summarize and chart the landscape of seminal immuno-oncology trials in HCC and envision future clinical developments.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/terapia , Neoplasias Hepáticas/terapia , Inibidores de Checkpoint Imunológico/uso terapêutico , Imunoterapia
6.
Oxf Med Case Reports ; 2022(1): omab138, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35083053

RESUMO

Non-bacterial thrombotic endocarditis (NBTE) is a rare condition characterized by non-infectious vegetations affecting the cardiac valves. Although systemic thromboembolism is a commonly associated condition, antiphospholipid syndrome is less common. Nevertheless, treatment generally involves long-term anticoagulation. We report a case of a patient with previously undiagnosed NBTE who suffered systemic thromboembolic events despite pre-existing treatment with a direct-acting oral anticoagulant.

7.
J Surg Case Rep ; 2021(10): rjab438, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34631009

RESUMO

Infective endocarditis is an important cause of morbidity and mortality, which classically presents with fevers and nonspecific symptoms. Afebrile infective endocarditis with negative blood cultures makes diagnosis more challenging and delays in treatment can occur increasing the likelihood of complications. The presence of prosthetic heart valves places patients at an increased risk of infective endocarditis and the case described below highlights the importance of considering this diagnosis even if classic clinical features such as fever and raised inflammatory markers are not present, as well as discussing an unusual complication of infective endocarditis; coronary artery embolism leading to myocardial infarction.

8.
J Paediatr Child Health ; 57(7): 1141, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34216163
9.
Lancet ; 397(10287): 1830-1841, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33965067

RESUMO

BACKGROUND: Metabolic-bariatric surgery delivers substantial weight loss and can induce remission or improvement of obesity-related risks and complications. However, more robust estimates of its effect on long-term mortality and life expectancy-especially stratified by pre-existing diabetes status-are needed to guide policy and facilitate patient counselling. We compared long-term survival outcomes of severely obese patients who received metabolic-bariatric surgery versus usual care. METHODS: We did a prespecified one-stage meta-analysis using patient-level survival data reconstructed from prospective controlled trials and high-quality matched cohort studies. We searched PubMed, Scopus, and MEDLINE (via Ovid) for randomised trials, prospective controlled studies, and matched cohort studies comparing all-cause mortality after metabolic-bariatric surgery versus non-surgical management of obesity published between inception and Feb 3, 2021. We also searched grey literature by reviewing bibliographies of included studies as well as review articles. Shared-frailty (ie, random-effects) and stratified Cox models were fitted to compare all-cause mortality of adults with obesity who underwent metabolic-bariatric surgery compared with matched controls who received usual care, taking into account clustering of participants at the study level. We also computed numbers needed to treat, and extrapolated life expectancy using Gompertz proportional-hazards modelling. The study protocol is prospectively registered on PROSPERO, number CRD42020218472. FINDINGS: Among 1470 articles identified, 16 matched cohort studies and one prospective controlled trial were included in the analysis. 7712 deaths occurred during 1·2 million patient-years. In the overall population consisting 174 772 participants, metabolic-bariatric surgery was associated with a reduction in hazard rate of death of 49·2% (95% CI 46·3-51·9, p<0·0001) and median life expectancy was 6·1 years (95% CI 5·2-6·9) longer than usual care. In subgroup analyses, both individuals with (hazard ratio 0·409, 95% CI 0·370-0·453, p<0·0001) or without (0·704, 0·588-0·843, p<0·0001) baseline diabetes who underwent metabolic-bariatric surgery had lower rates of all-cause mortality, but the treatment effect was considerably greater for those with diabetes (between-subgroup I2 95·7%, p<0·0001). Median life expectancy was 9·3 years (95% CI 7·1-11·8) longer for patients with diabetes in the surgery group than the non-surgical group, whereas the life expectancy gain was 5·1 years (2·0-9·3) for patients without diabetes. The numbers needed to treat to prevent one additional death over a 10-year time frame were 8·4 (95% CI 7·8-9·1) for adults with diabetes and 29·8 (21·2-56·8) for those without diabetes. Treatment effects did not appear to differ between gastric bypass, banding, and sleeve gastrectomy (I2 3·4%, p=0·36). By leveraging the results of this meta-analysis and other published data, we estimated that every 1·0% increase in metabolic-bariatric surgery utilisation rates among the global pool of metabolic-bariatric candidates with and without diabetes could yield 5·1 million and 6·6 million potential life-years, respectively. INTERPRETATION: Among adults with obesity, metabolic-bariatric surgery is associated with substantially lower all-cause mortality rates and longer life expectancy than usual obesity management. Survival benefits are much more pronounced for people with pre-existing diabetes than those without. FUNDING: None.


Assuntos
Cirurgia Bariátrica , Diabetes Mellitus Tipo 2/complicações , Obesidade/cirurgia , Estudos de Casos e Controles , Causas de Morte , Estudos de Coortes , Ensaios Clínicos Controlados como Assunto , Humanos , Expectativa de Vida , Mortalidade , Obesidade/complicações , Modelos de Riscos Proporcionais , Estudos Prospectivos , Ensaios Clínicos Controlados Aleatórios como Assunto , Taxa de Sobrevida
12.
Antioxid Redox Signal ; 34(18): 1484-1497, 2021 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-33198508

RESUMO

Significance: Hypoxia is emerging as a crucial regulator of the tumor microenvironment; it governs the metastatic potential of multiple primary cancers. It is also potentially involved in the regulation of tumorigenesis, tumor metabolism, and proangiogenic activity. Recent Advances: A wealth of clinical data across a wide range of cancer types has revealed strong correlations between hypoxia or the overexpression of hypoxia-inducible transcription factors and the rates of distant metastases and poor prognoses. Hypoxia-inducible factor (HIF)-1α, one of the key regulatory molecules of the HIF-1 signaling pathways, is involved in multiple crucial steps in the metastatic cascade. Critical Issues: Here, we present recent findings on the roles of the HIF-1 complex in tumor metastasis and highlight the potential of HIF-1α as a target for abrogating tumor metastasis. Moreover, we systematically describe the regulatory role of HIF-1 at each step of the metastatic cascade. Finally, we present the most recent advances in potential pharmacological interventions and the development of specific HIF-1 inhibitors for blocking tumor metastasis. Future Directions: Well-designed clinical trials are urgently needed to validate the anti-metastatic activity of HIF-1 inhibitors discovered in preclinical models. Antioxid. Redox Signal. 34, 1484-1497.


Assuntos
Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Metástase Neoplásica/genética , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Movimento Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Metástase Neoplásica/tratamento farmacológico , Prognóstico , Transdução de Sinais/efeitos dos fármacos , Hipóxia Tumoral/efeitos dos fármacos , Microambiente Tumoral/efeitos dos fármacos
14.
J Am Chem Soc ; 142(47): 19992-20001, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33180477

RESUMO

We report the discovery of a new superprotonic compound, Cs7(H4PO4)(H2PO4)8, or CPP, which forms at elevated temperatures from the reaction of CsH2PO4 and CsH5(PO4)2. The structure, solved using high-temperature single-crystal X-ray diffraction and confirmed by high-temperature 31P NMR spectroscopy, crystallizes in space group Pm3̅n and has a lattice constant of 20.1994(9) Å at 130 °C. The unit cell resembles a 4 × 4 × 4 superstructure of superprotonic CsH2PO4, but features an extraordinary chemical moiety, rotationally disordered H4PO4+ cations, which periodically occupy one of every eight cation sites. The influence of this remarkable cation on the structure, thermodynamics, and proton transport properties of the CPP phase is discussed. Notably, CPP forms at a temperature of 90 °C, much lower than the superprotonic transition temperature of 228 °C of CsH2PO4, and the compound does not appear to have an ordered, low-temperature form. Under nominally dry conditions, the material is stable against dehydration to ∼151 °C, and this results in a particularly wide region of stability of a superprotonic material in the absence of active humidification. The conductivity of Cs7(H4PO4)(H2PO4)8 is moderate, 5.8 × 10-4 S cm-1 at 140 °C, but appears nevertheless facilitated by polyanion (H2PO4-) group reorientation.

15.
Ann Surg ; 272(2): 253-265, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32675538

RESUMO

OBJECTIVE: To perform an individual participant data meta-analysis using randomized trials and propensity-score matched (PSM) studies which compared laparoscopic versus open hepatectomy for patients with colorectal liver metastases (CLM). BACKGROUND: Randomized trials and PSM studies constitute the highest level of evidence in addressing the long-term oncologic efficacy of laparoscopic versus open resection for CLM. However, individual studies are limited by the reporting of overall survival in ways not amenable to traditional methods of meta-analysis, and violation of the proportional hazards assumption. METHODS: Survival information of individual patients was reconstructed from the published Kaplan-Meier curves with the aid of a computer vision program. Frequentist and Bayesian survival models (taking into account random-effects and nonproportional hazards) were fitted to compare overall survival of patients who underwent laparoscopic versus open surgery. To handle long plateaus in the tails of survival curves, we also exploited "cure models" to estimate the fraction of patients effectively "cured" of disease. RESULTS: Individual patient data from 2 randomized trials and 13 PSM studies involving 3148 participants were reconstructed. Laparoscopic resection was associated with a lower hazard rate of death (stratified hazard ratio = 0.853, 95% confidence interval: 0.754-0.965, P = 0.0114), and there was evidence of time-varying effects (P = 0.0324) in which the magnitude of hazard ratios increased over time. The fractions of long-term cancer survivors were estimated to be 47.4% and 18.0% in the laparoscopy and open surgery groups, respectively. At 10-year follow-up, the restricted mean survival time was 8.6 months (or 12.1%) longer in the laparoscopy arm (P < 0.0001). In a subgroup analysis, elderly patients (≥65 years old) treated with laparoscopy experienced longer 3-year average life expectancy (+6.2%, P = 0.018), and those who live past the 5-year milestone (46.1%) seem to be cured of disease. CONCLUSIONS: This patient-level meta-analysis of high-quality studies demonstrated an unexpected survival benefit in favor of laparoscopic over open resection for CLM in the long-term. From a conservative viewpoint, these results can be interpreted to indicate that laparoscopy is at least not inferior to the standard open approach.


Assuntos
Neoplasias Colorretais/patologia , Laparoscopia/mortalidade , Laparotomia/mortalidade , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/secundário , Idoso , Teorema de Bayes , Intervalo Livre de Doença , Feminino , Hepatectomia/métodos , Humanos , Estimativa de Kaplan-Meier , Laparoscopia/métodos , Laparotomia/métodos , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Prognóstico , Pontuação de Propensão , Modelos de Riscos Proporcionais , Ensaios Clínicos Controlados Aleatórios como Assunto , Análise de Sobrevida
16.
ASAIO J ; 66(2): 132-138, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-30913099

RESUMO

At fixed speed, the spontaneous increase in pump flow accompanying exercise in patients with continuous flow left ventricular assist devices (cfLVADs) is slight in comparison to normal physiologic response, limiting exercise capacity. We systematically exercised 14 patients implanted with an isolated HeartWare HVAD undergoing routine right heart catheterization at baseline and at maximal safe pump speed. In addition to hemodynamics, mixed venous oxygen saturation (SvO2), echocardiography and noninvasive mean arterial pressure, and heart rate were measured. Significantly greater pump flows were achieved with maximum pump speed compared with baseline speed at rest (mean ± standard deviation [SD]: 5.0 ± 0.7 vs. 4.6 ± 0.8 L/min) and peak exercise (6.7 ± 1.0 vs. 5.9 ± 0.9 L/min, p = 0.001). Pulmonary capillary wedge pressure was significantly reduced with maximum pump speed compared to baseline pump speed at rest (10 ± 4 vs. 15 ± 5 mmHg, p < 0.001) and peak exercise (27 ± 8 vs. 30 ± 8 mmHg, p = 0.002). Mixed venous oxygen saturation decreased with exercise (p < 0.001) but was unaffected by changes in pump speed. In summary, although higher pump speeds synergistically augment the increase in pump flow associated with exercise and blunt the exercise-induced rise in left heart filling pressures, elevated filling pressures and markedly diminished SvO2 persist at maximal safe pump speed, suggesting that physiologic flow increases are not met by isolated cfLVADs in the supported failing heart.


Assuntos
Exercício Físico/fisiologia , Insuficiência Cardíaca/fisiopatologia , Coração Auxiliar , Hemodinâmica/fisiologia , Feminino , Humanos , Masculino
17.
ACS Med Chem Lett ; 10(11): 1524-1529, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31749905

RESUMO

Small molecules that inhibit the metabolic enzyme NAMPT have emerged as potential therapeutics in oncology. As part of our effort in this area, we took a scaffold morphing approach and identified 3-pyridyl azetidine ureas as a potent NAMPT inhibiting motif. We explored the SAR of this series, including 5 and 6 amino pyridines, using a convergent synthetic strategy. This lead optimization campaign yielded multiple compounds with excellent in vitro potency and good ADME properties that culminated in compound 27.

18.
JACC Cardiovasc Imaging ; 12(8 Pt 2): 1618-1628, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30660547

RESUMO

OBJECTIVES: This study aimed to determine the role of T1 mapping in identifying cardiac allograft rejection. BACKGROUND: Endomyocardial biopsy (EMBx), the current gold standard to diagnose cardiac allograft rejection, is associated with potentially serious complications. Cardiac magnetic resonance (CMR)-based T1 mapping detects interstitial edema and fibrosis, which are important markers of acute and chronic rejection. Therefore, T1 mapping can potentially diagnose cardiac allograft rejection noninvasively. METHODS: Patients underwent CMR within 24 h of EMBx. T1 maps were acquired at 1.5-T. EMBx-determined rejection was graded according to International Society of Heart and Lung Transplant (ISHLT) criteria. RESULTS: Of 112 biopsies with simultaneous CMR, 60 were classified as group 0 (ISHLT grade 0), 35 as group 1 (ISHLT grade 1R), and 17 as group 2 (2R, 3R, clinically diagnosed rejection, antibody-mediated rejection). Native T1 values in patients with grade 0 biopsies and left ventricular ejection fraction >60% (983 ± 42 ms; 95% confidence interval: 972 to 994 ms) were comparable to values in nontransplant healthy control subjects (974 ± 45 ms; 95% confidence interval: 962 to 987 ms). T1 values were significantly higher in group 2 (1,066 ± 78 ms) versus group 0 (984 ± 42 ms; p = 0.0001) and versus group 1 (1,001 ± 54 ms; p = 0.001). After excluding patients with an estimated glomerular filtration rate <50 ml/min/m2, there was a moderate correlation of log-transformed native T1 with high-sensitivity troponin T (r = 0.54, p < 0.0001) and pro-B-type natriuretic peptide (r = 0.67, p < 0.0001). Using a T1 cutoff value of 1,029 ms, the sensitivity, specificity, and negative predictive value were 93%, 79%, and 99%, respectively. CONCLUSIONS: Myocardial tissue characterization with T1 mapping displays excellent negative predictive capacity for the noninvasive detection of cardiac allograft rejection and holds promise to reduce substantially the EMBx requirement in cardiac transplant rejection surveillance.


Assuntos
Edema Cardíaco/diagnóstico por imagem , Rejeição de Enxerto/diagnóstico por imagem , Transplante de Coração/efeitos adversos , Imagem Cinética por Ressonância Magnética , Adulto , Aloenxertos , Biópsia , Estudos de Casos e Controles , Estudos Transversais , Edema Cardíaco/imunologia , Edema Cardíaco/patologia , Edema Cardíaco/fisiopatologia , Feminino , Fibrose , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Rejeição de Enxerto/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Miocárdio/imunologia , Miocárdio/patologia , Valor Preditivo dos Testes , Estudos Prospectivos , Volume Sistólico , Resultado do Tratamento , Função Ventricular Esquerda , Adulto Jovem
19.
Acta Ophthalmol ; 97(2): e238-e247, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30259687

RESUMO

PURPOSE: To conduct a multi-tissue investigation on the penetration and distribution of topical atropine in myopia treatment, and determine if atropine is detectable in the untreated contralateral eye after uniocular instillation. METHODS: Nine mature New Zealand white rabbits were evenly divided into three groups. Each group was killed at 5, 24 and 72 hr, respectively, following uniocular instillation of 0.05 ml of 1% atropine. Tissues were sampled after enucleation: conjunctiva, sclera, cornea, iris, ciliary body, lens, retina, aqueous, and vitreous humors. The assay for atropine was performed using liquid chromatography-mass spectrometry (LC-MS), and molecular tissue distribution was illustrated using matrix-assisted laser desorption ionization-imaging mass spectrometry (MALDI-IMS) via an independent experiment on murine eyes. RESULTS: At 5 hr, the highest (mean ± SEM) concentration of atropine was detected in the conjunctiva (19.05 ± 5.57 ng/mg, p < 0.05) with a concentration gradient established anteriorly to posteriorly, as supported by MALDI-IMS. At 24 hr, preferential binding of atropine to posterior ocular tissues occurred, demonstrating a reversal of the initial concentration gradient. Atropine has good ocular bioavailability with concentrations of two magnitudes higher than its binding affinity in most tissues at 3 days. Crossing-over of atropine to the untreated eye occurred within 5 hr post-administration. CONCLUSION: Both transcorneal and transconjunctival-scleral routes are key in atropine absorption. Posterior ocular tissues could be important sites of action by atropine in myopic reduction. In uniocular atropine trials, cross-over effects on the placebo eye should be adjusted to enhance results reliability. Combining the use of LC-MS and MALDI-IMS can be a viable approach in the study of the ocular pharmacokinetics of atropine.


Assuntos
Humor Aquoso/metabolismo , Atropina/farmacocinética , Miopia/tratamento farmacológico , Corpo Vítreo/metabolismo , Administração Tópica , Animais , Atropina/administração & dosagem , Cromatografia Líquida , Modelos Animais de Doenças , Midriáticos/administração & dosagem , Midriáticos/farmacocinética , Miopia/metabolismo , Soluções Oftálmicas , Coelhos , Espectrometria de Massas em Tandem , Distribuição Tecidual
20.
Circ Genom Precis Med ; 11(8): e002135, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30354343

RESUMO

Background Truncating variants in the TTN gene ( TTNtv) are common in patients with dilated cardiomyopathy (DCM) but also occur in the general population. Whether TTNtv are sufficient to cause DCM or require a second hit for DCM manifestation is an important clinical issue. Methods We generated a zebrafish model of an A-band TTNtv identified in 2 human DCM families in which early-onset disease appeared to be precipitated by ventricular volume overload. Cardiac phenotypes were serially assessed from 0 to 12 months using video microscopy, high-frequency echocardiography, and histopathologic analysis. The effects of sustained hemodynamic stress resulting from an anemia-induced hyperdynamic state were also evaluated. Results Homozygous ttna mutants had severe cardiac dysmorphogenesis and premature death, whereas heterozygous mutants ( ttnatv/+) survived into adulthood and spontaneously developed DCM. Six-month-old ttnatv/+ fish had reduced baseline ventricular systolic function and failed to mount a hypercontractile response when challenged by hemodynamic stress. Pulsed wave and tissue Doppler analysis also revealed unsuspected ventricular diastolic dysfunction in ttnatv/+ fish with prolonged isovolumic relaxation and increased diastolic passive stiffness in the absence of myocardial fibrosis. These defects reduced diastolic reserve under stress conditions and resulted in disproportionately greater atrial dilation than observed in wild-type fish. Conclusions Heterozygosity for A-band titin truncation is sufficient to cause DCM in adult zebrafish. Abnormalities of systolic and diastolic reserve in titin-truncated fish reduce stress tolerance and may contribute to a substrate for atrial arrhythmogenesis. These data suggest that hemodynamic stress may be an important modifiable risk factor in human TTNtv-related DCM.


Assuntos
Cardiomiopatia Dilatada/genética , Conectina/genética , Hemodinâmica/genética , Estresse Fisiológico/genética , Adaptação Biológica/genética , Adolescente , Adulto , Idoso , Animais , Animais Geneticamente Modificados , Cardiomiopatia Dilatada/patologia , Cardiomiopatia Dilatada/fisiopatologia , Embrião não Mamífero , Feminino , Estudos de Associação Genética , Coração/embriologia , Coração/crescimento & desenvolvimento , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Sarcômeros/patologia , Deleção de Sequência , Volume Sistólico/genética , Adulto Jovem , Peixe-Zebra
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