Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 274
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Circulation ; 148(10): 808-818, 2023 09 05.
Artículo en Inglés | MEDLINE | ID: mdl-37463608

RESUMEN

BACKGROUND: In hypertrophic cardiomyopathy (HCM), myocyte disarray and microvascular disease (MVD) have been implicated in adverse events, and recent evidence suggests that these may occur early. As novel therapy provides promise for disease modification, detection of phenotype development is an emerging priority. To evaluate their utility as early and disease-specific biomarkers, we measured myocardial microstructure and MVD in 3 HCM groups-overt, either genotype-positive (G+LVH+) or genotype-negative (G-LVH+), and subclinical (G+LVH-) HCM-exploring relationships with electrical changes and genetic substrate. METHODS: This was a multicenter collaboration to study 206 subjects: 101 patients with overt HCM (51 G+LVH+ and 50 G-LVH+), 77 patients with G+LVH-, and 28 matched healthy volunteers. All underwent 12-lead ECG, quantitative perfusion cardiac magnetic resonance imaging (measuring myocardial blood flow, myocardial perfusion reserve, and perfusion defects), and cardiac diffusion tensor imaging measuring fractional anisotropy (lower values expected with more disarray), mean diffusivity (reflecting myocyte packing/interstitial expansion), and second eigenvector angle (measuring sheetlet orientation). RESULTS: Compared with healthy volunteers, patients with overt HCM had evidence of altered microstructure (lower fractional anisotropy, higher mean diffusivity, and higher second eigenvector angle; all P<0.001) and MVD (lower stress myocardial blood flow and myocardial perfusion reserve; both P<0.001). Patients with G-LVH+ were similar to those with G+LVH+ but had elevated second eigenvector angle (P<0.001 after adjustment for left ventricular hypertrophy and fibrosis). In overt disease, perfusion defects were found in all G+ but not all G- patients (100% [51/51] versus 82% [41/50]; P=0.001). Patients with G+LVH- compared with healthy volunteers similarly had altered microstructure, although to a lesser extent (all diffusion tensor imaging parameters; P<0.001), and MVD (reduced stress myocardial blood flow [P=0.015] with perfusion defects in 28% versus 0 healthy volunteers [P=0.002]). Disarray and MVD were independently associated with pathological electrocardiographic abnormalities in both overt and subclinical disease after adjustment for fibrosis and left ventricular hypertrophy (overt: fractional anisotropy: odds ratio for an abnormal ECG, 3.3, P=0.01; stress myocardial blood flow: odds ratio, 2.8, P=0.015; subclinical: fractional anisotropy odds ratio, 4.0, P=0.001; myocardial perfusion reserve odds ratio, 2.2, P=0.049). CONCLUSIONS: Microstructural alteration and MVD occur in overt HCM and are different in G+ and G- patients. Both also occur in the absence of hypertrophy in sarcomeric mutation carriers, in whom changes are associated with electrocardiographic abnormalities. Measurable changes in myocardial microstructure and microvascular function are early-phenotype biomarkers in the emerging era of disease-modifying therapy.


Asunto(s)
Cardiomiopatía Hipertrófica , Hipertrofia Ventricular Izquierda , Humanos , Sarcómeros/genética , Imagen de Difusión Tensora , Predisposición Genética a la Enfermedad , Mutación , Cardiomiopatía Hipertrófica/diagnóstico , Fenotipo , Biomarcadores , Fibrosis
2.
Magn Reson Med ; 91(4): 1556-1566, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38073070

RESUMEN

PURPOSE: To demonstrate the feasibility of motion compensating diffusion gradient schemes in the acquisition of quality diffusion tensor images (DTI) of the brain during continuous gross head motion. METHODS: Five healthy subjects were scanned using a clinical 3 T MRI with and without continuous head motion. For one volunteer, DTI data was acquired using standard (M0) diffusion-weighted (DW) gradients, and first (M1) and second (M2) order gradient schemes that were previously developed for use in cardiac DTI. In four additional volunteers, DTI data was acquired with M0 and M2 gradients. DTI parameters were calculated and compared with established retrospective motion corrections. RESULTS: In the absence of motion, DTI parameters calculated from M0, M1, and M2 data were consistent. In the presence of motion, up to 44% of DW images acquired with M0 gradients were corrupted by signal dropout, compared to 0% of the M2 images. In voxelwise comparisons, DTI parameters calculated using motion-M0 data were elevated compared to reference data. Retrospective corrections for extreme motion applied to motion-M0 data did not improve consistency with reference data in cases where motion corrupted >15% of DW images. In contrast, DTI parameters calculated with motion-M2 data were consistent with reference data. CONCLUSION: This proof-of-principle study demonstrates that motion compensating diffusion gradients can mitigate artifacts because of continuous motion in DTI of the brain and offers promise for improved DTI accessibility. Further study will be necessary to determine the robustness of the approach in patient populations with high susceptibility to head motion.


Asunto(s)
Encéfalo , Imagen de Difusión Tensora , Humanos , Imagen de Difusión Tensora/métodos , Estudios Retrospectivos , Encéfalo/diagnóstico por imagen , Movimiento (Física) , Imagen por Resonancia Magnética , Imagen de Difusión por Resonancia Magnética/métodos
3.
Magn Reson Med ; 91(6): 2546-2558, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38376096

RESUMEN

PURPOSE: We aimed to develop a free-breathing (FB) cardiac DTI (cDTI) method based on short-axis PROPELLER (SAP) and M2 motion compensated spin-echo EPI (SAP-M2-EPI) to mitigate geometric distortion and eliminate aliasing in acquired diffusion-weighted (DW) images, particularly in patients with a higher body mass index (BMI). THEORY AND METHODS: The study involved 10 healthy volunteers whose BMI values fell into specific categories: BMI <25 (4 volunteers), 25< BMI <28 (5 volunteers), and BMI >30 (1 volunteer). We compared DTI parameters, including fractional anisotropy (FA), mean diffusivity (MD), and helix angle transmurality (HAT), between SAP-M2-EPI and M2-ssEPI. To evaluate the performance of SAP-M2-EPI in reducing geometric distortions in the left ventricle (LV) compared to CINE and M2-ssEPI, we utilized the DICE similarity coefficient (DSC) and assessed misregistration area. RESULTS: In all volunteers, SAP-M2-EPI yielded high-quality LV DWIs without aliasing, demonstrating significantly reduced geometric distortion (with an average DSC of 0.92 and average misregistration area of 90 mm2) and diminished signal loss due to bulk motion when compared to M2-ssEPI. DTI parameter maps exhibited consistent patterns across slices without motion related artifacts. CONCLUSION: SAP-M2-EPI facilitates free-breathing cDTI of the entire LV, effectively eliminating aliasing and minimizing geometric distortion compared to M2-ssEPI. Furthermore, it preserves accurate quantification of myocardial microstructure.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Imagen de Difusión Tensora , Humanos , Estudios de Factibilidad , Imagen de Difusión Tensora/métodos , Imagen de Difusión por Resonancia Magnética/métodos , Corazón/diagnóstico por imagen , Ventrículos Cardíacos/diagnóstico por imagen , Imagen Eco-Planar/métodos
4.
Magn Reson Med ; 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-39313764

RESUMEN

PURPOSE: Our aim is to assess the potential of an MR system with ultrahigh performance gradients (200 mT/m maximum gradient strength) to address two interrelated challenges in cardiac DTI: low SNR and sensitivity to bulk motion. METHODS: Imaging was performed in 20 healthy volunteers, two patients, and one swine post-myocardial infarction. The impact of maximum gradient strength was assessed with spin echo cardiac DTI featuring second-order motion compensation and varying maximum system gradient strengths (40, 80, 200 mT/m). Motion compensation requirements at 200 mT/m were assessed with sequences featuring zeroth-, first-, and second-order motion compensation. SNR, mean diffusivity, fractional anisotropy, helix angle transmurality, and secondary eigenvector angle in the left ventricle were compared. RESULTS: Increasing maximum system gradient strength from 40 and 80 mT/m to 200 mT/m increased SNR of b = 500 s/mm2 images by 150% and 40% due to reductions in TE. Observed improvements in DTI metrics included reduction in variance in mean diffusivity and helix angle transmurality across healthy volunteers, improved visualization of myocardial borders and delineation of suspected scar. Whereas second-order motion compensation acquisitions were robust to motion-induced signal dropout, zeroth- and first-order motion compensation acquisitions suffered from severe signal loss and localized signal voids, respectively. CONCLUSION: Ultrahigh performance gradients (200 mT/m) enable high SNR DWIs of the heart and resultant improvements in diffusion tensor metrics. Despite reduced diffusion-encoding duration, second-order motion compensation is required to overcome sensitivity to cardiac motion.

5.
Clin Endocrinol (Oxf) ; 100(4): 350-357, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-37807424

RESUMEN

OBJECTIVES: To determine all-cause in-hospital mortality associated with severe hypernatraemia and the causes, comorbidities, time to treatment, discharge destination and postdischarge mortality. DESIGN: Retrospective observational cohort study. PATIENTS: Severe hypernatraemia, (sodium concentration ≥ 155 mmol/L), at any time during a tertiary hospital admission in Melbourne, Australia, 1 January 2019 to 31 December 2019 (pre-COVID19). MEASUREMENTS: Deaths, Charlson Comorbidity Index (CCI), hypernatraemia causes, time to treatment, discharge destination. RESULTS: One hundred and one inpatients: 64 community-acquired, 37 hospital-acquired. In-hospital mortality was 38%, but cumulative mortality was 65% by 1 month after discharge, with only a minor further increase at 6 and 12 months. After adjusting for peak sodium concentration, the community acquired group had significantly reduced odds of in-hospital mortality (odds ratio 0.15, 95% confidence interval [0.04-0.54], p = .003). Iatrogenic factors were present in 57% (21/37) of the hospital-acquired group. Only 55% of all cases received active sodium directed treatment. Time to start treatment did not affect outcomes. High levels of comorbidity were present, median CCI (IQR) was 6 (5-8) in the community and 5 (4-7) in the hospital group. Dementia prevalence was higher in the community group, 66% (42/64) versus 19% (7/37) (p = .001). Infection was the most common precipitant with 52% (33/64) in the community and 32% (12/37) in the hospital group. Of the survivors, 32% who had been living independently required residential care after discharge. CONCLUSIONS: Mortality was high and loss of independence in survivors common. To potentially improve outcomes, hypernatraemia-specific guidelines should be formulated and efforts made to reduce system and iatrogenic factors.


Asunto(s)
Hipernatremia , Humanos , Hipernatremia/etiología , Estudios Retrospectivos , Pacientes Internos , Cuidados Posteriores , Alta del Paciente , Sodio , Enfermedad Iatrogénica/epidemiología
6.
Circ Res ; 131(12): 980-1000, 2022 12 02.
Artículo en Inglés | MEDLINE | ID: mdl-36367103

RESUMEN

BACKGROUND: RBPs (RNA-binding proteins) perform indispensable functions in the post-transcriptional regulation of gene expression. Numerous RBPs have been implicated in cardiac development or physiology based on gene knockout studies and the identification of pathogenic RBP gene mutations in monogenic heart disorders. The discovery and characterization of additional RBPs performing indispensable functions in the heart will advance basic and translational cardiovascular research. METHODS: We performed a differential expression screen in zebrafish embryos to identify genes enriched in nkx2.5-positive cardiomyocytes or cardiopharyngeal progenitors compared to nkx2.5-negative cells from the same embryos. We investigated the myocardial-enriched gene RNA-binding protein with multiple splicing (variants) 2 [RBPMS2)] by generating and characterizing rbpms2 knockout zebrafish and human cardiomyocytes derived from RBPMS2-deficient induced pluripotent stem cells. RESULTS: We identified 1848 genes enriched in the nkx2.5-positive population. Among the most highly enriched genes, most with well-established functions in the heart, we discovered the ohnologs rbpms2a and rbpms2b, which encode an evolutionarily conserved RBP. Rbpms2 localizes selectively to cardiomyocytes during zebrafish heart development and strong cardiomyocyte expression persists into adulthood. Rbpms2-deficient embryos suffer from early cardiac dysfunction characterized by reduced ejection fraction. The functional deficit is accompanied by myofibril disarray, altered calcium handling, and differential alternative splicing events in mutant cardiomyocytes. These phenotypes are also observed in RBPMS2-deficient human cardiomyocytes, indicative of conserved molecular and cellular function. RNA-sequencing and comparative analysis of genes mis-spliced in RBPMS2-deficient zebrafish and human cardiomyocytes uncovered a conserved network of 29 ortholog pairs that require RBPMS2 for alternative splicing regulation, including RBFOX2, SLC8A1, and MYBPC3. CONCLUSIONS: Our study identifies RBPMS2 as a conserved regulator of alternative splicing, myofibrillar organization, and calcium handling in zebrafish and human cardiomyocytes.


Asunto(s)
Calcio , Miocardio , Proteínas de Unión al ARN , Proteínas de Pez Cebra , Animales , Humanos , Calcio/metabolismo , Miocardio/metabolismo , Miocitos Cardíacos/metabolismo , Proteínas Represoras/metabolismo , Factores de Empalme de ARN/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Pez Cebra/genética , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo
7.
J Int Neuropsychol Soc ; : 1-14, 2024 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-39291438

RESUMEN

OBJECTIVE: The number of test translations and adaptations has risen exponentially over the last two decades, and these processes are now becoming a common practice. The International Test Commission (ITC) Guidelines for Translating and Adapting Tests (Second Edition, 2017) offer principles and practices to ensure the quality of translated and adapted tests. However, they are not specific to the cognitive processes examined with clinical neuropsychological measures. The aim of this publication is to provide a specialized set of recommendations for guiding neuropsychological test translation and adaptation procedures. METHODS: The International Neuropsychological Society's Cultural Neuropsychology Special Interest Group established a working group tasked with extending the ITC guidelines to offer specialized recommendations for translating/adapting neuropsychological tests. The neuropsychological application of the ITC guidelines was formulated by authors representing over ten nations, drawing upon literature concerning neuropsychological test translation, adaptation, and development, as well as their own expertise and consulting colleagues experienced in this field. RESULTS: A summary of neuropsychological-specific commentary regarding the ITC test translation and adaptation guidelines is presented. Additionally, examples of applying these recommendations across a broad range of criteria are provided to aid test developers in attaining valid and reliable outcomes. CONCLUSIONS: Establishing specific neuropsychological test translation and adaptation guidelines is critical to ensure that such processes produce reliable and valid psychometric measures. Given the rapid global growth experienced in neuropsychology over the last two decades, the recommendations may assist researchers and practitioners in carrying out such endeavors.

8.
J Intensive Care Med ; : 8850666241255345, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38881385

RESUMEN

Background: Patients in the intensive care unit (ICU) often experience poor sleep quality. Pharmacologic sleep aids are frequently used as primary or adjunctive therapy to improve sleep, although their benefits in the ICU remain uncertain. This review aims to provide a comprehensive assessment of the objective and subjective effects of medications used for sleep in the ICU, as well as their adverse effects. Methods: PubMed, Web of Science, Scopus, Embase, and Cochrane Central Register of Controlled Trials were systematically searched from their inception until June 2023 for comparative studies assessing the effects of pharmacologic sleep aids on objective and subjective metrics of sleep. Results: Thirty-four studies with 3498 participants were included. Medications evaluated were melatonin, ramelteon, suvorexant, propofol, and dexmedetomidine. The majority of studies were randomized controlled trials. Melatonin and dexmedetomidine were the best studied agents. Objective sleep metrics included polysomnography (PSG), electroencephalography (EEG), bispectral index, and actigraphy. Subjective outcome measures included patient questionnaires and nursing observations. Evidence for melatonin as a sleep aid in the ICU was mixed but largely not supportive for improving sleep. Evidence for ramelteon, suvorexant, and propofol was too limited to offer definitive recommendations. Both objective and subjective data supported dexmedetomidine as an effective sleep aid in the ICU, with PSG/EEG in 303 ICU patients demonstrating increased sleep duration and efficiency, decreased arousal index, decreased percentage of stage N1 sleep, and increased absolute and percentage of stage N2 sleep. Mild bradycardia and hypotension were reported as side effects of dexmedetomidine, whereas the other medications were reported to be safe. Several ongoing studies have not yet been published, mostly on melatonin and dexmedetomidine. Conclusions: While definitive conclusions cannot be made for most medications, dexmedetomidine improved sleep quantity and quality in the ICU. These benefits need to be balanced with possible hemodynamic side effects.

9.
J Intensive Care Med ; : 8850666241246748, 2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38602149

RESUMEN

Malnutrition in adult intensive care unit patients is associated with poor clinical outcomes. Providing adequate nutritional support to the critically ill adult should be an important goal for the intensivist. This narrative review aims to delineate the role of parenteral nutrition (PN) in meeting nutritional goals. We examined the data regarding the safety and efficacy of PN compared to enteral nutrition. In addition, we describe practical considerations for the use of PN in the ICU including patient nutritional risk stratification, nutrient composition selection for PN, route of PN administration, and biochemical monitoring.

10.
Surg Endosc ; 38(9): 5246-5252, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38992284

RESUMEN

OBJECTIVE: While sleeve gastrectomy (SG) results in sustained weight loss for the majority of patients, some will experience inadequate weight loss or weight regain requiring revision. The objective of this study was to evaluate differences in weight loss over time between patients undergoing Roux-en-Y gastric bypass (RYGB) or single anastomosis duodenoileostomy (SADI) after SG. METHODS: We queried a single institution's bariatrics registry to identify patients who underwent RYGB or SADI after previous SG over a three-year period. Demographics, operative characteristics, and post-operative complications were evaluated. Interval total body weight loss (TBWL) and excess body weight loss (EBWL) were calculated from available follow-ups within 2 years. RESULTS: We identified 124 patients who underwent conversion to RYGB (n = 61) or SADI (n = 63) following previous SG. There were no differences in sex, age, or medical comorbidities between groups. The median initial BMI was higher in the SADI group (44.9 vs. 41.9 for RYGB, p = 0.03) with greater excess body weight (56.7 vs. 64.3 kg, p = 0.04). The SADI group had a shorter median operative duration (157 vs. 182 min for RYGB, p < 0.01) and lower readmission rates (0 vs. 14.75%, p < 0.01). There was no difference in post-operative complications or need for rehydration therapy between the groups. Among 122 patients (98.4%) that had follow-up weights available, there were no differences in TBWL between groups. RYGB patients had a higher EBWL at 2, 3, and 6 months (p < 0.05 for all comparisons), but there were no differences between RYGB and SADI at 1 or 2 years. CONCLUSIONS: Both RYGB and SADI conversions proved effective for further weight loss following failed SG at our academic center. While neither demonstrated clear superiority in long-term (> 1 year) weight loss, RYGB's restrictive gastric pouch may explain its early weight loss advantage.


Asunto(s)
Gastrectomía , Derivación Gástrica , Obesidad Mórbida , Pérdida de Peso , Humanos , Masculino , Femenino , Derivación Gástrica/métodos , Gastrectomía/métodos , Adulto , Persona de Mediana Edad , Obesidad Mórbida/cirugía , Estudios Retrospectivos , Reoperación/estadística & datos numéricos , Insuficiencia del Tratamiento , Duodenostomía/métodos , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/epidemiología
11.
Endocr Pract ; 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39187158

RESUMEN

OBJECTIVE: To evaluate the effects of teprotumumab on ophthalmologic and biochemical findings and assess potential genetic markers for response to treatment. METHODS: This is a retrospective study. Participants were 18-76 year old. All subjects were treated with teprotumumab. The primary outcome was the change in proptosis before and after teprotumumab treatment. Secondary outcomes include change in other ophthalmic measures and thyroid laboratory tests. Human leukocyte antigens (HLA) markers were analyzed for response to teprotumumab. RESULTS: Twenty-six patients were included in the final analysis. There was a significant decrease in thyroid stimulating immunoglobulin and thyrotropin receptor antibody levels and significant increases in glycated hemoglobin A1c, fasting glucose, and total T3 levels. There was also significant reduction in proptosis, clinical activity score, retinal nerve fiber layer thickness, ganglion cell analysis, and intraocular pressure. HLA haplotypes were distinct between responders and nonresponders, with HLA-DRB3 02:02:01G, HLA-DRB4 neg, and HLA-DQB1 02:01:01G demonstrating better response to teprotumumab and HLA-A 23:01:01G strongly correlating to nonresponse. CONCLUSIONS: Patients with both acute and chronic thyroid eye disease treated with teprotumumab had a significant reduction in thyroid stimulating immunoglobulin and thyrotropin receptor antibody levels and improvement in proptosis, clinical activity score, retinal nerve fiber layer and ganglion cell analysis thickness, and intraocular pressure. HLA may predict responders vs nonresponders. Further studies with longer duration and larger population comparing teprotumumab with steroids or other immunomodulatory agents (tocilizumab, rituximab, etc) may be helpful.

12.
Magn Reson Med ; 89(3): 990-1001, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36300861

RESUMEN

PURPOSE: The noninvasive measurement of biological tissue elasticity is an evolving technology that enables the robust characterization of soft tissue mechanics for a wide array of biomedical engineering and clinical applications. We propose, design, and implement here a new MRI technique termed asynchronous magnetic resonance elastography (aMRE) that pushes the measurement technology toward a driverless implementation. This technique can be added to clinical MRI scanners without any additional specialized hardware. THEORY: Asynchronous MRE is founded on the theory of diffuse wavefields and noise correlation previously developed in ultrasound to reconstruct shear wave speeds using seemingly incoherent wavefields. Unlike conventional elastography methods that solve an inverse problem, aMRE directly reconstructs a pixel-wise mapping of wave speed using the spatial-temporal statistics of the measured wavefield. METHODS: Incoherent finger tapping served as the wave-generating source for all aMRE measurements. Asynchronous MRE was performed on a phantom using a Siemens Prismafit as an experimental validation of the theory. It was further performed on thigh muscles as a proof-of-concept implementation of in vivo imaging using a Siemens Skyra scanner. RESULTS: Numerical and phantom experiments show an accurate reconstruction of wave speeds from seemingly noisy wavefields. The proof-of-concept thigh experiments also show that the aMRE protocol can reconstruct a pixel-wise mapping of wave speeds. CONCLUSION: Asynchronous MRE is shown to accurately reconstruct shear wave speeds in phantom experiments and remains at the proof-of-concept stage for in vivo imaging. After further validation and improvements, it has the potential to lower both the technical and monetary barriers of entry to measuring tissue elasticity.


Asunto(s)
Diagnóstico por Imagen de Elasticidad , Diagnóstico por Imagen de Elasticidad/métodos , Ultrasonografía , Elasticidad , Fantasmas de Imagen , Imagen por Resonancia Magnética/métodos
13.
Magn Reson Med ; 90(4): 1594-1609, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37288580

RESUMEN

PURPOSE: Modern high-amplitude gradient systems can be limited by the International Electrotechnical Commission 60601-2-33 cardiac stimulation (CS) limit, which was set in a conservative manner based on electrode experiments and E-field simulations in uniform ellipsoidal body models. Here, we show that coupled electromagnetic-electrophysiological modeling in detailed body and heart models can predict CS thresholds, suggesting that such modeling might lead to more detailed threshold estimates in humans. Specifically, we compare measured and predicted CS thresholds in eight pigs. METHODS: We created individualized porcine body models using MRI (Dixon for the whole body, CINE for the heart) that replicate the anatomy and posture of the animals used in our previous experimental CS study. We model the electric fields induced along cardiac Purkinje and ventricular muscle fibers and predict the electrophysiological response of these fibers, yielding CS threshold predictions in absolute units for each animal. Additionally, we assess the total modeling uncertainty through a variability analysis of the 25 main model parameters. RESULTS: Predicted and experimental CS thresholds agree within 19% on average (normalized RMS error), which is smaller than the 27% modeling uncertainty. No significant difference was found between the modeling predictions and experiments (p < 0.05, paired t-test). CONCLUSION: Predicted thresholds matched the experimental data within the modeling uncertainty, supporting the model validity. We believe that our modeling approach can be applied to study CS thresholds in humans for various gradient coils, body shapes/postures, and waveforms, which is difficult to do experimentally.


Asunto(s)
Fenómenos Electromagnéticos , Corazón , Humanos , Porcinos , Animales , Corazón/diagnóstico por imagen , Imagen por Resonancia Magnética , Ventrículos Cardíacos , Electricidad
14.
Magn Reson Med ; 89(5): 1901-1914, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36585915

RESUMEN

PURPOSE: To substantially shorten the acquisition time required for quantitative three-dimensional (3D) chemical exchange saturation transfer (CEST) and semisolid magnetization transfer (MT) imaging and allow for rapid chemical exchange parameter map reconstruction. METHODS: Three-dimensional CEST and MT magnetic resonance fingerprinting (MRF) datasets of L-arginine phantoms, whole-brains, and calf muscles from healthy volunteers, cancer patients, and cardiac patients were acquired using 3T clinical scanners at three different sites, using three different scanner models and coils. A saturation transfer-oriented generative adversarial network (GAN-ST) supervised framework was then designed and trained to learn the mapping from a reduced input data space to the quantitative exchange parameter space, while preserving perceptual and quantitative content. RESULTS: The GAN-ST 3D acquisition time was 42-52 s, 70% shorter than CEST-MRF. The quantitative reconstruction of the entire brain took 0.8 s. An excellent agreement was observed between the ground truth and GAN-based L-arginine concentration and pH values (Pearson's r > 0.95, ICC > 0.88, NRMSE < 3%). GAN-ST images from a brain-tumor subject yielded a semi-solid volume fraction and exchange rate NRMSE of 3 . 8 ± 1 . 3 % $$ 3.8\pm 1.3\% $$ and 4 . 6 ± 1 . 3 % $$ 4.6\pm 1.3\% $$ , respectively, and SSIM of 96 . 3 ± 1 . 6 % $$ 96.3\pm 1.6\% $$ and 95 . 0 ± 2 . 4 % $$ 95.0\pm 2.4\% $$ , respectively. The mapping of the calf-muscle exchange parameters in a cardiac patient, yielded NRMSE < 7% and SSIM > 94% for the semi-solid exchange parameters. In regions with large susceptibility artifacts, GAN-ST has demonstrated improved performance and reduced noise compared to MRF. CONCLUSION: GAN-ST can substantially reduce the acquisition time for quantitative semi-solid MT/CEST mapping, while retaining performance even when facing pathologies and scanner models that were not available during training.


Asunto(s)
Neoplasias Encefálicas , Imagen por Resonancia Magnética , Humanos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética , Encéfalo/diagnóstico por imagen , Arginina
15.
Magn Reson Med ; 90(1): 222-230, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-36864561

RESUMEN

PURPOSE: To investigate the feasibility of combining simultaneous multislice (SMS) and region-optimized virtual coils (ROVir) for single breath-hold CINE imaging. METHOD: ROVir is a recent virtual coil approach that allows reduced-field of view (FOV) imaging by localizing the signal from a region-of-interest (ROI) and/or suppressing the signal from unwanted spatial regions. In this work, ROVir is used for reduced-FOV SMS bSSFP CINE imaging, which enables whole heart CINE with a single breath-hold acquisition. RESULTS: Reduced-FOV CINE with either SMS-only or ROVir-only resulted in significant aliasing, with severely reduced image quality when compared to the full FOV reference CINE, while the visual appearance of aliasing was substantially reduced with the proposed SMS+ROVir. The end diastolic volume, end systolic volume, and ejection fraction obtained using the proposed approach were similar to the clinical reference (correlations of 0.92, 0.94, and 0.88, respectively with p < 0 . 05 $$ p<0.05 $$ in each case, and biases of 0.1, 1.6 mL, and - 0 . 6 % $$ -0.6\% $$ , respectively). No statistically significant differences for these parameters were found with a Wilcoxon rank test (p = 0.96, 0.20, and 0.40, respectively). CONCLUSION: We demonstrated that reduced-FOV CINE imaging with SMS+ROVir enables single breath-hold whole-heart imaging without compromising visual image quality or quantitative cardiac function parameters.


Asunto(s)
Contencion de la Respiración , Imagen por Resonancia Cinemagnética , Imagen por Resonancia Cinemagnética/métodos , Reproducibilidad de los Resultados , Interpretación de Imagen Asistida por Computador/métodos
16.
Invest New Drugs ; 41(2): 350-355, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-37004644

RESUMEN

Mycosis fungoides (MF) and Sézary Syndrome (SS) are the most common subtypes of cutaneous T cell lymphomas (CTCL). Advanced-stage MF/SS have poor prognoses and may be refractory to multiple systemic treatments. These cases can be difficult to achieve and maintain complete response and there is a need for novel therapeutics. Inhibition of the phosphatidylinositol 3-kinase (PI3K) pathway by Tenalisib presents one such emerging drug. We report a relapsed/refractory SS patient achieving complete remission using the combination of Tenalisib and Romidepsin and subsequently maintaining long-duration CR with Tenalisib monotherapy.


Asunto(s)
Linfoma Cutáneo de Células T , Síndrome de Sézary , Neoplasias Cutáneas , Humanos , Síndrome de Sézary/tratamiento farmacológico , Síndrome de Sézary/patología , Fosfatidilinositol 3-Quinasas , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/patología , Linfoma Cutáneo de Células T/tratamiento farmacológico
17.
J Surg Res ; 282: 147-154, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36274449

RESUMEN

INTRODUCTION: Although imaging plays no role in diagnosing primary hyperparathyroidism (PHPT), preoperative localization is essential for a focused parathyroidectomy. We hypothesized that reviewing imaging obtained prior to PHPT diagnosis can identify enlarged parathyroid glands and provide information that might potentially impact the preoperative evaluation and intraoperative course of patients undergoing parathyroidectomy. METHODS: We included adult patients with PHPT who underwent parathyroidectomy between October 2015 and October 2020 and had contrast-enhanced computed tomography (CT) imaging of the lower neck and upper chest obtained prior to diagnosis for unrelated indications. A radiologist reviewed the prediagnosis CTs blinded to subsequent parathyroid localization imaging and operative findings. A surgeon assessed the radiologist's findings in the context of each case to determine the potential impact of information from old imaging on surgical decision-making. RESULTS: We identified at least one enlarged parathyroid gland on prior contrast-enhanced CT in 30 (75%) of 40 included patients. Despite old imaging enabling correct localization, 60% of these 30 underwent dedicated parathyroid imaging prior to parathyroidectomy. Knowledge of the enlarged parathyroid(s) on prior imaging might have allowed a more focused approach in 10.0% and prompted a more thorough exploration in 13.3%. In the total cohort, reviewing prior imaging could have provided information capable of changing the preoperative evaluation in 52.5% and the operative course in 17.5%. CONCLUSIONS: The identification of enlarged parathyroid glands on contrast-enhanced CT imaging that predates a diagnosis of PHPT is possible. Prospective studies might verify the impact of these findings on the preoperative evaluation and operative course of patients undergoing parathyroidectomy.


Asunto(s)
Hiperparatiroidismo Primario , Neoplasias de las Paratiroides , Adulto , Humanos , Paratiroidectomía/métodos , Hiperparatiroidismo Primario/diagnóstico por imagen , Hiperparatiroidismo Primario/cirugía , Hiperparatiroidismo Primario/patología , Neoplasias de las Paratiroides/cirugía , Estudios Prospectivos , Glándulas Paratiroides/diagnóstico por imagen , Glándulas Paratiroides/cirugía , Glándulas Paratiroides/patología , Tomografía Computarizada por Rayos X , Hiperplasia/patología , Hormona Paratiroidea , Estudios Retrospectivos
18.
Arterioscler Thromb Vasc Biol ; 42(2): e61-e73, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34809448

RESUMEN

OBJECTIVE: Arterial stiffness is a risk factor for cardiovascular disease, including heart failure with preserved ejection fraction (HFpEF). MGP (matrix Gla protein) is implicated in vascular calcification in animal models, and circulating levels of the uncarboxylated, inactive form of MGP (ucMGP) are associated with cardiovascular disease-related and all-cause mortality in human studies. However, the role of MGP in arterial stiffness is uncertain. Approach and Results: We examined the association of ucMGP levels with vascular calcification, arterial stiffness including carotid-femoral pulse wave velocity (PWV), and incident heart failure in community-dwelling adults from the Framingham Heart Study. To further investigate the link between MGP and arterial stiffness, we compared aortic PWV in age- and sex-matched young (4-month-old) and aged (10-month-old) wild-type and Mgp+/- mice. Among 7066 adults, we observed significant associations between higher levels of ucMGP and measures of arterial stiffness, including higher PWV and pulse pressure. Longitudinal analyses demonstrated an association between higher ucMGP levels and future increases in systolic blood pressure and incident HFpEF. Aortic PWV was increased in older, but not young, female Mgp+/- mice compared with wild-type mice, and this augmentation in PWV was associated with increased aortic elastin fiber fragmentation and collagen accumulation. CONCLUSIONS: This translational study demonstrates an association between ucMGP levels and arterial stiffness and future HFpEF in a large observational study, findings that are substantiated by experimental studies showing that mice with Mgp heterozygosity develop arterial stiffness. Taken together, these complementary study designs suggest a potential role of therapeutically targeting MGP in HFpEF.


Asunto(s)
Proteínas de Unión al Calcio/sangre , Proteínas de la Matriz Extracelular/sangre , Insuficiencia Cardíaca/sangre , Rigidez Vascular , Animales , Presión Sanguínea , Proteínas de Unión al Calcio/genética , Proteínas de la Matriz Extracelular/genética , Femenino , Eliminación de Gen , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/fisiopatología , Humanos , Estudios Longitudinales , Masculino , Ratones Endogámicos C57BL , Persona de Mediana Edad , Estudios Prospectivos , Volumen Sistólico , Proteína Gla de la Matriz
19.
Int J Mol Sci ; 24(3)2023 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-36768560

RESUMEN

Photoacoustic imaging using external contrast agents is emerging as a powerful modality for real-time molecular imaging of deep-seated tumors. There are several chromophores, such as indocyanine green and IRDye800, that can potentially be used for photoacoustic imaging; however, their use is limited due to several drawbacks, particularly photostability. There is, therefore, an urgent need to design agents to enhance contrast in photoacoustic imaging. Naphthalocyanine dyes have been demonstrated for their use as photoacoustic contrast agents; however, their low solubility in aqueous solvents and high aggregation propensity limit their application. In this study, we report the synthesis and characterization of silicon-centered naphthalocyanine dyes with high aqueous solubility and near infra-red (NIR) absorption in the range of 850-920 nm which make them ideal candidates for photoacoustic imaging. A series of Silicon-centered naphthalocyanine dyes were developed with varying axial and peripheral substitutions, all in an attempt to enhance their aqueous solubility and improve photophysical properties. We demonstrate that axial incorporation of charged ammonium mesylate group enhances water solubility. Moreover, the incorporation of peripheral 2-methoxyethoxy groups at the α-position modulates the electronic properties by altering the π-electron delocalization and enhancing photoacoustic signal amplitude. In addition, all the dyes were synthesized to incorporate an N-hydroxysuccinimidyl group to enable further bioconjugation. In summary, we report the synthesis of water-soluble silicon-centered naphthalocyanine dyes with a high photoacoustic signal amplitude that can potentially be used as contrast agents for molecular photoacoustic imaging.


Asunto(s)
Colorantes , Técnicas Fotoacústicas , Medios de Contraste , Solubilidad , Silicio , Imagen Molecular , Agua , Técnicas Fotoacústicas/métodos , Colorantes Fluorescentes
20.
Am J Physiol Lung Cell Mol Physiol ; 322(2): L204-L223, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-34878944

RESUMEN

During newborn lung injury, excessive activity of lysyl oxidases (LOXs) disrupts extracellular matrix (ECM) formation. Previous studies indicate that TGFß activation in the O2-injured mouse pup lung increases lysyl oxidase (LOX) expression. But how TGFß regulates this, and whether the LOXs generate excess pulmonary aldehydes are unknown. First, we determined that O2-mediated lung injury increases LOX protein expression in TGFß-stimulated pup lung interstitial fibroblasts. This regulation appeared to be direct; this is because TGFß treatment also increased LOX protein expression in isolated pup lung fibroblasts. Then using a fibroblast cell line, we determined that TGFß stimulates LOX expression at a transcriptional level via Smad2/3-dependent signaling. LOX is translated as a pro-protein that requires secretion and extracellular cleavage before assuming amine oxidase activity and, in some cells, reuptake with nuclear localization. We found that pro-LOX is processed in the newborn mouse pup lung. Also, O2-mediated injury was determined to increase pro-LOX secretion and nuclear LOX immunoreactivity particularly in areas populated with interstitial fibroblasts and exhibiting malformed ECM. Then, using molecular probes, we detected increased aldehyde levels in vivo in O2-injured pup lungs, which mapped to areas of increased pro-LOX secretion in lung sections. Increased activity of LOXs plays a critical role in the aldehyde generation; an inhibitor of LOXs prevented the elevation of aldehydes in the O2-injured pup lung. These results reveal new mechanisms of TGFß and LOX in newborn lung disease and suggest that aldehyde-reactive probes might have utility in sensing the activation of LOXs in vivo during lung injury.


Asunto(s)
Aldehídos/metabolismo , Lesión Pulmonar/metabolismo , Pulmón/enzimología , Pulmón/patología , Proteína-Lisina 6-Oxidasa/metabolismo , Aldehídos/química , Animales , Animales Recién Nacidos , Embrión de Mamíferos/patología , Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Regulación Enzimológica de la Expresión Génica , Ratones , Ratones Endogámicos C57BL , Sondas Moleculares/metabolismo , Células 3T3 NIH , Proteína-Lisina 6-Oxidasa/genética , Alveolos Pulmonares/metabolismo , Alveolos Pulmonares/patología , Transducción de Señal , Proteínas Smad/metabolismo , Transcripción Genética , Factor de Crecimiento Transformador beta/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA