Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 152
Filtrar
Más filtros

Intervalo de año de publicación
1.
Development ; 150(14)2023 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-37366057

RESUMEN

The earliest skeletal muscle progenitor cells (SMPCs) derived from human pluripotent stem cells (hPSCs) are often identified by factors expressed by a diverse number of progenitors. An early transcriptional checkpoint that defines myogenic commitment could improve hPSC differentiation to skeletal muscle. Analysis of several myogenic factors in human embryos and early hPSC differentiations found SIX1+PAX3+ co-expression was most indictive of myogenesis. Using dCas9-KRAB hPSCs, we demonstrate that early inhibition of SIX1 alone significantly decreased PAX3 expression, reduced PAX7+ SMPCs, and myotubes later in differentiation. Emergence of SIX1+PAX3+ precursors can be improved by manipulating seeding density, monitoring metabolic secretion and altering the concentration of CHIR99021. These modifications resulted in the co-emergence of hPSC-derived sclerotome, cardiac and neural crest that we hypothesized enhanced hPSC myogenic differentiation. Inhibition of non-myogenic lineages modulated PAX3 independent of SIX1. To better understand SIX1 expression, we compared directed differentiations to fetal progenitors and adult satellite cells by RNA-seq. Although SIX1 continued to be expressed across human development, SIX1 co-factor expression was dependent on developmental timing. We provide a resource to enable efficient derivation of skeletal muscle from hPSCs.


Asunto(s)
Células Madre Pluripotentes , Adulto , Humanos , Factor de Transcripción PAX3/genética , Factor de Transcripción PAX3/metabolismo , Células Madre Pluripotentes/metabolismo , Diferenciación Celular/genética , Músculo Esquelético/metabolismo , Desarrollo de Músculos/genética , Factor de Transcripción PAX7/genética , Factor de Transcripción PAX7/metabolismo , Proteínas de Homeodominio/metabolismo
2.
Proc Natl Acad Sci U S A ; 120(21): e2218775120, 2023 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-37186832

RESUMEN

Quantum computing technology may soon deliver revolutionary improvements in algorithmic performance, but it is useful only if computed answers are correct. While hardware-level decoherence errors have garnered significant attention, a less recognized obstacle to correctness is that of human programming errors-"bugs." Techniques familiar to most programmers from the classical domain for avoiding, discovering, and diagnosing bugs do not easily transfer, at scale, to the quantum domain because of its unique characteristics. To address this problem, we have been working to adapt formal methods to quantum programming. With such methods, a programmer writes a mathematical specification alongside the program and semiautomatically proves the program correct with respect to it. The proof's validity is automatically confirmed-certified-by a "proof assistant." Formal methods have successfully yielded high-assurance classical software artifacts, and the underlying technology has produced certified proofs of major mathematical theorems. As a demonstration of the feasibility of applying formal methods to quantum programming, we present a formally certified end-to-end implementation of Shor's prime factorization algorithm, developed as part of a framework for applying the certified approach to general applications. By leveraging our framework, one can significantly reduce the effects of human errors and obtain a high-assurance implementation of large-scale quantum applications in a principled way.

3.
Gynecol Oncol ; 185: 42-45, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38367302

RESUMEN

INTRODUCTION: The formative period of the specialty of gynecologic oncology was from 1968 to 1972 and became a board-certified specialty in 1973. During this formation there were no Black physicians participating in this process. We chronicle and document the incorporation of the first three board-certified Black physicians in the specialty of gynecologic oncology here for historical purposes. METHODS: We highlight the hostile climate experienced by Black physicians before and during the formation of gynecologic oncology, review the acceptance and training of the first three Black physicians in the specialty and recognize their significant contributions to the field. RESULTS: The biographies and the narrative of these men describe their impact and contribution to medicine. We chronicle the historic presence of the first board-certified Black gynecologic oncologists and pelvic surgeons in the United States. CONCLUSION: These three men represent the Black Founding Fathers of gynecologic oncology. Their perseverance in the face of adversity and commitment to excellence have left an indelible impact on the institutions that they developed, the individuals that they trained, and the patients that they served.


Asunto(s)
Negro o Afroamericano , Ginecología , Oncología Médica , Humanos , Negro o Afroamericano/historia , Negro o Afroamericano/psicología , Oncología Médica/historia , Ginecología/historia , Historia del Siglo XX , Femenino , Estados Unidos , Masculino
4.
Gynecol Oncol ; 184: 236-242, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38382150

RESUMEN

INTRODUCTION: Endometrial cancer is the most commonly diagnosed female genital tract malignancy in the United States of America. Racial disparities surrounding this particular disease have been extensively investigated for over 26-years. We sought to determine if research in this area has led to any significant improvements in this disparity. METHODS: We performed a rapid systematic review of English language publications on racial disparities in endometrial cancer among African American (AAW) and white American women (WAW), from 1997 to 2023. We looked at trends in incidence and survival; impact of known poor prognostic factors (stage at diagnosis, histological subtypes, grade); co-morbidities; differences in treatment (surgery, radiation and chemotherapy); socioeconomic factors; differences in biological and genetic markers; and policies/declarations. RESULTS: During the period under review (1997-2023), there was a notable increase in both disease incidence (39%) and mortality (26%) rates for AAW, in comparison to WAW among whom the incidence rates increased by 2% and mortality rates rose, but 9% less than for AAW. It should be noted that the current incidence rate of 29.4% in AAW represent a reversal of what is was 26-years ago, when the incidence rate was 17.8%. In comparison to WAW, AAW had a higher prevalence of poor prognostic variables, more co-morbidities, lower income levels, less insurance coverage, and were more frequently under treated with surgery, chemotherapy and radiation. To date no actionable molecular/genetic markers have been identified. We were unable to locate any published recommendations or active programs of implementation strategies/policies designed to effectively mitigate the documented racial disparity. CONCLUSION: Racial disparities in disease incidence and mortality in endometrial cancer rates between WAW and AAW have widened during a 26-year period of robust research, suggesting that current research alone is not enough to eliminate this disparity. Based on this rapid systematic review we have identified and analyzed the impact of causation variables on this disparity. Additionally, we have made strong and pertinent recommendations for the benefit of mitigating this escalating racial disparity.


Asunto(s)
Negro o Afroamericano , Neoplasias Endometriales , Población Blanca , Humanos , Femenino , Neoplasias Endometriales/etnología , Neoplasias Endometriales/terapia , Neoplasias Endometriales/epidemiología , Neoplasias Endometriales/patología , Neoplasias Endometriales/mortalidad , Población Blanca/estadística & datos numéricos , Negro o Afroamericano/estadística & datos numéricos , Estados Unidos/epidemiología , Disparidades en el Estado de Salud , Incidencia , Disparidades en Atención de Salud/estadística & datos numéricos , Disparidades en Atención de Salud/etnología , Factores Socioeconómicos
5.
Bioorg Med Chem ; 85: 117273, 2023 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-37030194

RESUMEN

GPR40 AgoPAMs are highly effective antidiabetic agents that have a dual mechanism of action, stimulating both glucose-dependent insulin and GLP-1 secretion. The early lipophilic, aromatic pyrrolidine and dihydropyrazole GPR40 AgoPAMs from our laboratory were highly efficacious in lowering plasma glucose levels in rodents but possessed off-target activities and triggered rebound hyperglycemia in rats at high doses. A focus on increasing molecular complexity through saturation and chirality in combination with reducing polarity for the pyrrolidine AgoPAM chemotype resulted in the discovery of compound 46, which shows significantly reduced off-target activities as well as improved aqueous solubility, rapid absorption, and linear PK. In vivo, compound 46 significantly lowers plasma glucose levels in rats during an oral glucose challenge yet does not demonstrate the reactive hyperglycemia effect at high doses that was observed with earlier GPR40 AgoPAMs.


Asunto(s)
Glucemia , Hiperglucemia , Ratas , Animales , Receptores Acoplados a Proteínas G , Péptido 1 Similar al Glucagón , Hipoglucemiantes/farmacología , Pirrolidinas/farmacología , Pirrolidinas/química , Insulina
6.
J Nanobiotechnology ; 21(1): 303, 2023 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-37641124

RESUMEN

Skeletal muscle disease severity can often progress asymmetrically across muscle groups and heterogeneously within tissues. An example is Duchenne Muscular Dystrophy (DMD) in which lack of dystrophin results in devastating skeletal muscle wasting in some muscles whereas others are spared or undergo hypertrophy. An efficient, non-invasive approach to identify sites of asymmetry and degenerative lesions could enable better patient monitoring and therapeutic targeting of disease. In this study, we utilized a versatile intravenously injectable mesoporous silica nanoparticle (MSNP) based nanocarrier system to explore mechanisms of biodistribution in skeletal muscle of mdx mouse models of DMD including wildtype, dystrophic, and severely dystrophic mice. Moreover, MSNPs could be imaged in live mice and whole muscle tissues enabling investigation of how biodistribution is altered by different types of muscle pathology such as inflammation or fibrosis. We found MSNPs were tenfold more likely to aggregate within select mdx muscles relative to wild type, such as gastrocnemius and quadriceps. This was accompanied by decreased biodistribution in off-target organs. We found the greatest factor affecting preferential delivery was the regenerative state of the dystrophic skeletal muscle with the highest MSNP abundance coinciding with the regions showing the highest level of embryonic myosin staining and intramuscular macrophage uptake. To demonstrate, muscle regeneration regulated MSNP distribution, we experimentally induced regeneration using barium chloride which resulted in a threefold increase of intravenously injected MSNPs to sites of regeneration 7 days after injury. These discoveries provide the first evidence that nanoparticles have selective biodistribution to skeletal muscle in DMD to areas of active regeneration and that nanoparticles could enable diagnostic and selective drug delivery in DMD skeletal muscle.


Asunto(s)
Distrofina , Músculo Esquelético , Animales , Ratones , Distribución Tisular , Ratones Endogámicos mdx , Regeneración
7.
J Sep Sci ; 46(21): e2300300, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37715328

RESUMEN

Pharmaceutical development currently relies on quality separation methods from early discovery through to line-of-site manufacturing. There have been significant advancements made regarding the column particle packing, internal diameter, length connectivity, the understanding of the impact key parameters like void volume, flow rate, and temperature all that affects the resultant separation quality, that is, resolution, peak shape, peak width, run time, and signal-to-noise ratio. There is however a strong need to establish better alternatives to large bulky high-performance liquid chromatography racks either for process analytical reaction monitoring or mass spectrometry analysis in establishing product quality. Compact, portable high-pressure liquid chromatography can be a more efficient alternative to traditional ultra-high pressure liquid chromatography and traditional liquid chromatography. The compact versatile instrument evaluated here allows good separation control with either the on-board column with fixed ultra-violet wavelength cartridge or for use with a high-resolution mass spectrometry. Significant space reduction results in greener lab spaces with improved energy efficiency for smaller labs with lower energy demands. In addition, this compact liquid chromatography was used as a portable reaction monitoring solution to compare forced degradation kinetics and assess portable liquid chromatography-mass spectrometry capability for the analyses required for pharmaceutical drug product testing.

8.
Proc Natl Acad Sci U S A ; 117(6): 3053-3062, 2020 02 11.
Artículo en Inglés | MEDLINE | ID: mdl-31980526

RESUMEN

Genome sequencing has established clinical utility for rare disease diagnosis. While increasing numbers of individuals have undergone elective genome sequencing, a comprehensive study surveying genome-wide disease-associated genes in adults with deep phenotyping has not been reported. Here we report the results of a 3-y precision medicine study with a goal to integrate whole-genome sequencing with deep phenotyping. A cohort of 1,190 adult participants (402 female [33.8%]; mean age, 54 y [range 20 to 89+]; 70.6% European) had whole-genome sequencing, and were deeply phenotyped using metabolomics, advanced imaging, and clinical laboratory tests in addition to family/medical history. Of 1,190 adults, 206 (17.3%) had at least 1 genetic variant with pathogenic (P) or likely pathogenic (LP) assessment that suggests a predisposition of genetic risk. A multidisciplinary clinical team reviewed all reportable findings for the assessment of genotype and phenotype associations, and 137 (11.5%) had genotype and phenotype associations. A high percentage of genotype and phenotype associations (>75%) was observed for dyslipidemia (n = 24), cardiomyopathy, arrhythmia, and other cardiac diseases (n = 42), and diabetes and endocrine diseases (n = 17). A lack of genotype and phenotype associations, a potential burden for patient care, was observed in 69 (5.8%) individuals with P/LP variants. Genomics and metabolomics associations identified 61 (5.1%) heterozygotes with phenotype manifestations affecting serum metabolite levels in amino acid, lipid and cofactor, and vitamin pathways. Our descriptive analysis provides results on the integration of whole-genome sequencing and deep phenotyping for clinical assessments in adults.


Asunto(s)
Diagnóstico por Imagen , Metabolómica , Medicina de Precisión/métodos , Secuenciación Completa del Genoma , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Predisposición Genética a la Enfermedad/genética , Genotipo , Cardiopatías/genética , Humanos , Masculino , Persona de Mediana Edad , Fenotipo , Adulto Joven
9.
Anal Chem ; 94(40): 13795-13803, 2022 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-36154017

RESUMEN

N-Nitrosamines are strictly regulated in pharmaceutical products due to their carcinogenic nature. Therefore, the ability to rapidly and reliably identify the N-nitroso functionality is urgently needed. Unfortunately, not all ionized N-nitroso compounds produce diagnostic fragment ions and hence tandem mass spectrometry based on collision-activated dissociation (CAD) cannot be used to consistently identify the N-nitroso functionality. Therefore, a more reliable method was developed based on diagnostic functional-group selective ion-molecule reactions in a linear quadrupole ion trap mass spectrometer. 2-Methoxypropene (MOP) was identified as a reagent that reacts with protonated N-nitrosamines in a diagnostic manner by forming an adduct followed by the elimination of 2-propenol (CH3C(OH)═CH2]). From 18 protonated N-nitrosamine model compounds studied, 15 formed the diagnostic product ion. The lack of the diagnostic reaction for three of the N-nitrosamine model compounds was rationalized based on the presence of a pyridine ring that gets preferentially protonated instead of the N-nitroso functionality. These N-nitrosamines can be identified by subjecting a stable adduct formed upon ion-molecule reactions with MOP to CAD. Further, the ability to use ion-molecule reactions followed by CAD to differentiate protonated O-nitroso compounds with a pyridine ring from analogous N-nitrosamines was demonstrated This methodology is considered to be robust for the identification of the N-nitroso functionality in unknown analytes. Lastly, HPLC/MS2 experiments were performed to determine the detection limit for five FDA regulated N-nitrosamines.


Asunto(s)
Nitrosaminas , Espectrometría de Masas en Tándem , Iones/química , Preparaciones Farmacéuticas , Piridinas , Espectrometría de Masas en Tándem/métodos
10.
Anal Bioanal Chem ; 414(12): 3581-3591, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35441858

RESUMEN

Bioprocess development of increasingly challenging therapeutics and vaccines requires a commensurate level of analytical innovation to deliver critical assays across functional areas. Chromatography hyphenated to numerous choices of detection has undeniably been the preferred analytical tool in the pharmaceutical industry for decades to analyze and isolate targets (e.g., APIs, intermediates, and byproducts) from multicomponent mixtures. Among many techniques, ion exchange chromatography (IEX) is widely used for the analysis and purification of biopharmaceuticals due to its unique selectivity that delivers distinctive chromatographic profiles compared to other separation modes (e.g., RPLC, HILIC, and SFC) without denaturing protein targets upon isolation process. However, IEX method development is still considered one of the most challenging and laborious approaches due to the many variables involved such as elution mechanism (via salt, pH, or salt-mediated-pH gradients), stationary phase's properties (positively or negatively charged; strong or weak ion exchanger), buffer type and ionic strength as well as pH choices. Herein, we introduce a new framework consisting of a multicolumn IEX screening in conjunction with computer-assisted simulation for efficient method development and purification of biopharmaceuticals. The screening component integrates a total of 12 different columns and 24 mobile phases that are sequentially operated in a straightforward automated fashion for both cation and anion exchange modes (CEX and AEX, respectively). Optimal and robust operating conditions are achieved via computer-assisted simulation using readily available software (ACD Laboratories/LC Simulator), showcasing differences between experimental and simulated retention times of less than 0.5%. In addition, automated fraction collection is also incorporated into this framework, illustrating the practicality and ease of use in the context of separation, analysis, and purification of nucleotides, peptides, and proteins. Finally, we provide examples of the use of this IEX screening as a framework to identify efficient first dimension (1D) conditions that are combined with MS-friendly RPLC conditions in the second dimension (2D) for two-dimensional liquid chromatography experiments enabling purity analysis and identification of pharmaceutical targets.


Asunto(s)
Productos Biológicos , Cromatografía Líquida de Alta Presión/métodos , Cromatografía por Intercambio Iónico/métodos , Péptidos , Proteínas/análisis
11.
Proc Natl Acad Sci U S A ; 116(18): 8960-8965, 2019 04 30.
Artículo en Inglés | MEDLINE | ID: mdl-30988206

RESUMEN

Sequence variation data of the human proteome can be used to analyze 3D protein structures to derive functional insights. We used genetic variant data from nearly 140,000 individuals to analyze 3D positional conservation in 4,715 proteins and 3,951 homology models using 860,292 missense and 465,886 synonymous variants. Sixty percent of protein structures harbor at least one intolerant 3D site as defined by significant depletion of observed over expected missense variation. Structural intolerance data correlated with deep mutational scanning functional readouts for PPARG, MAPK1/ERK2, UBE2I, SUMO1, PTEN, CALM1, CALM2, and TPK1 and with shallow mutagenesis data for 1,026 proteins. The 3D structural intolerance analysis revealed different features for ligand binding pockets and orthosteric and allosteric sites. Large-scale data on human genetic variation support a definition of functional 3D sites proteome-wide.


Asunto(s)
Variación Genética/genética , Imagenología Tridimensional/métodos , Proteoma/genética , Sitios de Unión , Calmodulina/genética , Análisis Mutacional de ADN/métodos , Humanos , Ligandos , Proteína Quinasa 1 Activada por Mitógenos/genética , Modelos Moleculares , Conformación Molecular , Mutación , PPAR gamma/genética , Fosfohidrolasa PTEN/genética , Conformación Proteica , Proteína SUMO-1/genética , Enzimas Activadoras de Ubiquitina/genética
12.
Pain Med ; 22(4): 807-818, 2021 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-33779730

RESUMEN

OBJECTIVE: For many medical professionals dealing with patients with persistent pain following spine surgery, the term Failed back surgery syndrome (FBSS) as a diagnostic label is inadequate, misleading, and potentially troublesome. It misrepresents causation. Alternative terms have been suggested, but none has replaced FBSS. The International Association for the Study of Pain (IASP) published a revised classification of chronic pain, as part of the new International Classification of Diseases (ICD-11), which has been accepted by the World Health Organization (WHO). This includes the term Chronic pain after spinal surgery (CPSS), which is suggested as a replacement for FBSS. METHODS: This article provides arguments and rationale for a replacement definition. In order to propose a broadly applicable yet more precise and clinically informative term, an international group of experts was established. RESULTS: 14 candidate replacement terms were considered and ranked. The application of agreed criteria reduced this to a shortlist of four. A preferred option-Persistent spinal pain syndrome-was selected by a structured workshop and Delphi process. We provide rationale for using Persistent spinal pain syndrome and a schema for its incorporation into ICD-11. We propose the adoption of this term would strengthen the new ICD-11 classification. CONCLUSIONS: This project is important to those in the fields of pain management, spine surgery, and neuromodulation, as well as patients labeled with FBSS. Through a shift in perspective, it could facilitate the application of the new ICD-11 classification and allow clearer discussion among medical professionals, industry, funding organizations, academia, and the legal profession.


Asunto(s)
Dolor Crónico , Síndrome de Fracaso de la Cirugía Espinal Lumbar , Dolor Crónico/diagnóstico , Síndrome de Fracaso de la Cirugía Espinal Lumbar/diagnóstico , Humanos , Clasificación Internacional de Enfermedades , Manejo del Dolor , Columna Vertebral
13.
Neuromodulation ; 24(4): 610-621, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32329155

RESUMEN

BACKGROUND: Dorsal root ganglion stimulation (DRG-S) is a novel approach to treat chronic pain. Lead placement at L2 has been reported to be an effective treatment for axial low back pain (LBP) primarily of discogenic etiology. We have recently shown, in a diverse cohort including cases of multilevel instrumentation following extensive prior back surgeries, that DRG-S lead placement at T12 is another promising target. Local effects at the T12 DRG, alone, are insufficient to explain these results. MATERIALS AND METHODS: We performed a literature review to explore the mechanisms of LBP relief with T12 DRG-S. FINDINGS: Branches of individual spinal nerve roots innervate facet joints and posterior spinal structures, while the discs and anterior vertebrae are carried via L2, and converge in the dorsal horn (DH) of the spinal cord at T8-T9. The T12 nerve root contains cutaneous afferents from the low back and enters the DH of the spinal cord at T10. Low back Aδ and C-fibers then ascend via Lissauer's tract (LT) to T8-T9, converging with other low back afferents. DRG-S at T12, then, results in inhibition of the converged low back fibers via endorphin-mediated and GABAergic frequency-dependent mechanisms. Therefore, T12 lead placement may be the optimal location for DRG-S to treat LBP.


Asunto(s)
Dolor Crónico , Dolor de la Región Lumbar , Estimulación de la Médula Espinal , Ganglios Espinales , Humanos , Dolor de la Región Lumbar/terapia , Columna Vertebral
14.
Neuromodulation ; 24(4): 746-752, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33227827

RESUMEN

BACKGROUND: Dorsal root ganglion neurostimulation (DRG-S) is effective in treating various refractory chronic pain syndromes. In preclinical studies, DRG-S at very low frequencies (<5 Hz) reduces excitatory output in the superficial dorsal horn. Clinically, we have also observed the effectiveness of DRG-S at low frequencies. We conducted a case series to describe the effect of very low-frequency DRG-S stimulation on clinical outcomes. MATERIALS AND METHODS: DRG-S for refractory low back pain was initiated at parameters consistent with published values. Thereafter, the stimulation frequency of DRG-S was reduced in a stepwise fashion to the lowest frequency that maintained pain relief. Pain intensity, disability, and general health status data were collected at baseline, prior to initiation of tapering, and at four weeks after each patient's lowest effective stimulation frequency was reached. RESULTS: After device activation (N = 20), DRG-S frequency was tapered from 16 to 4 Hz over a 4- to 17-week period, reducing charge-per-second by nearly two-thirds. Even so, pain relief was maintained at more than 75%, with consistent findings in the other measures. CONCLUSION: DRG-S may have utility in treating chronic pain at lower stimulation frequencies than previously recognized. We have previously theorized that the mechanism of action may involve preferential recruitment of low-threshold mechanoreceptor fibers via the endogenous opioid system. Of clinical relevance, lower frequency stimulation maintains DRG-S efficacy regarding improvements in pain, disability, and quality of life. It can extend battery life and may potentially lead to the development of smaller implantable pulse generators.


Asunto(s)
Dolor Crónico , Estimulación de la Médula Espinal , Dolor Crónico/terapia , Ganglios Espinales , Humanos , Manejo del Dolor , Calidad de Vida
15.
Neuromodulation ; 24(4): 738-745, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33236811

RESUMEN

BACKGROUND: Dorsal root ganglion stimulation (DRG-S) involves the electrical modulation of the somata of afferent neural fibers to treat chronic pain. DRG-S has demonstrated clinical efficacy at frequencies lower than typically used with spinal cord stimulation (SCS). In a clinical study, we found that the frequency of DRG-S can be tapered to a frequency as low as 4 Hz with no loss of efficacy. This review discusses possible mechanisms of action underlying effective pain relief with very low-frequency DRG-S. MATERIALS AND METHODS: We performed a literature review to explore the role of frequency in neural transmission and the corresponding relevance of frequency settings with neuromodulation. FINDINGS: Sensory neural transmission is a frequency-modulated system, with signal frequency determining which mechanisms are activated in the dorsal horn. In the dorsal horn, low-frequency signaling (<20 Hz) activates inhibitory processes while higher frequencies (>25 Hz) are excitatory. Physiologically, low-threshold mechanoreceptors (LTMRs) fibers transmit or modulate innocuous mechanical touch at frequencies as low as 0.5-5 Hz, while nociceptive fibers transmit pain at high frequencies. We postulate that very low-frequency DRG-S, at least partially, harnesses LTMRs and the native endogenous opioid system. Utilizing lower stimulation frequency decreases the total energy delivery used for DRG-S, extends battery life, and facilitates the development of devices with smaller generators.


Asunto(s)
Dolor Crónico , Estimulación de la Médula Espinal , Dolor Crónico/terapia , Ganglios Espinales , Humanos , Fibras Nerviosas , Manejo del Dolor
16.
Neuromodulation ; 24(6): 971-982, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33098229

RESUMEN

INTRODUCTION: Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy (RSD), is a difficult to treat condition characterized by debilitating pain and limitations in functional ability. Neuromodulation, in the form of spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS), have been traditionally used as a treatment for CRPS with variable success. OBJECTIVE: This chart review describes the use of implantable PNS systems in the treatment of CRPS of the upper and lower extremities spanning nearly three decades. MATERIALS AND METHODS: A retrospective chart review was performed on 240 patients with PNS implanted between 1990 and 2017 at our institution. Of these, 165 patients were identified who had PNS systems implanted for a diagnosis of CRPS. Patient profile, including baseline characteristics, comorbidities, past/current interventions/medications and targeted nerves, was descriptively summarized through standard summary statistics. Patients' pain scores and opioid consumptions at baseline (preimplant), 1 month, 6 months, and 12 months were collected and compared. Device revisions and explants were summarized, and patient functional outcomes were described. RESULTS: Pain scores at baseline and at 12-month follow-up were decreased from a mean of 7.4 ± 1.6 to 5.5 ± 2.4 and estimated to be 1.87 (95% CI: [1.29, 2.46], paired t-test p-value <0.001) lower at 12 months. At baseline, 62% of patients were on chronic opioid therapy, compared with 41% at 12 months. Of 126 patients who reported changes in functional status, 64 (51%) reported improvement, 27 (21%) reported worsening, and 35 (28%) did not report any meaningful change. Excluding end-of-life battery replacements, surgical revision occurred in 56 (34%) of patients. Thirteen patients (8%) underwent implantation of a second PNS because of symptomatic expansion outside of the original painful region. Device explant was performed in 32 (19%) of patients. Median length of follow-up was 74 [14, 147] months. Of the 36 patients who continue to follow-up at our institution, 29 (81%) continue to use their PNS. CONCLUSIONS: We can conclude that PNS is a useful modality to improve function and reduce long-term pain in selected patients suffering from CRPS type I and type II.


Asunto(s)
Síndromes de Dolor Regional Complejo , Distrofia Simpática Refleja , Estimulación de la Médula Espinal , Síndromes de Dolor Regional Complejo/terapia , Humanos , Nervios Periféricos , Distrofia Simpática Refleja/terapia , Estudios Retrospectivos
17.
Philos Stud ; 178(2): 533-557, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33442071

RESUMEN

Humeans are often accused of positing laws which fail to explain or are involved in explanatory circularity. Here, I will argue that these arguments are confused, but not because of anything to do with Humeanism: rather, they rest on false assumptions about causal explanation. I'll show how these arguments can be neatly sidestepped if one takes on two plausible commitments which are motivated independently of Humeanism: first, that laws don't directly feature in scientific explanation (a view defended recently by Ruben in R Inst Philos Suppl 27:95-117, 1990, 10.1017/S1358246100005063 and Skow in Reasons why, Oxford University Press, Oxford, 2016) and second, the view that explanation is contrastive. After outlining and motivating these views, I show how they bear on explanation-based arguments against Humeanism.

18.
J Asthma ; 56(10): 1110-1119, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-30273510

RESUMEN

Objective: We aimed to perform a meta-analysis evaluating the efficacy and safety of dupilumab in patients with uncontrolled asthma. Data source: A search of electronic databases was performed using PubMed, Cochrane library and Embase. Study selection: The literature search was conducted independently by two reviewers. Only randomized controlled trials (RCTs) that compared between placebo and dupilumab in patients with uncontrolled asthma were included in this analysis. Pooled risk ratios (RRs) and mean differences (MDs) with their corresponding 95% confidence intervals (CIs) were calculated for dichotomous and continuous data, respectively. Results: A total of four RCTs representing 2,992 patients were included. Pooled analysis showed significant reductions of the annualized rate of severe asthma exacerbation in the dupilumab group compared with placebo (RR 0.44; 95% CI 0.35-0.055; P < 0.01; I2 = 42%). In addition, the absolute forced expiratory volume at 1 s (FEV1) changes were significantly increased for the dupilumab group (MD 0.14; 95% CI: 0.12-0.17; P < 0.01; I2 = 0%). Finally, there were no significant differences between both groups in the development of any adverse event, serious adverse events, adverse events leading to death, discontinuation of medication due to adverse event or the occurrence of upper respiratory tract, influenza or bronchitis infections. However, dupilumab was associated with an increased risk of injection site reactions compared with placebo (RR 1.91; 95% CI 1.41, 2.59; P < 0.01; I2 = 24%). Conclusion: Among patients with uncontrolled asthma, the addition of dupilumab was associated with a reduced risk of severe asthma exacerbations and improvement in FEV1 without an increased risk of adverse events apart from injection site reactions with dupilumab.


Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Asma/diagnóstico , Asma/tratamiento farmacológico , Femenino , Volumen Espiratorio Forzado/efectos de los fármacos , Humanos , Inyecciones Subcutáneas , Masculino , Seguridad del Paciente , Pronóstico , Ensayos Clínicos Controlados Aleatorios como Asunto , Pruebas de Función Respiratoria , Medición de Riesgo , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
19.
Hum Genet ; 137(6-7): 447-458, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29978320

RESUMEN

Whole genome sequencing (WGS) was performed to identify the variants responsible for inherited retinal degeneration (IRD) in a Caucasian family. Segregation analysis of selected rare variants with pathogenic potential identified a set of compound heterozygous changes p.Arg266*:c.796C>T and p.Ala568Thr:c.1702G>A in the intraflagellar transport protein-88 (IFT88) gene segregating with IRD. Expression of IFT88 with the p.Arg266* and p.Ala568Thr mutations in mIMDC3 cells by transient transfection and in HeLa cells by introducing the mutations using CRISPR-cas9 system suggested that both mutations result in the formation of abnormal ciliary structures. The introduction of the IFT88 p.Arg266* variant in the homozygous state in HeLa cells by CRISPR-Cas9 genome-editing revealed that the mutant transcript undergoes nonsense-mediated decay leading to a significant depletion of IFT88 transcript. Additionally, abnormal ciliogenesis was observed in these cells. These observations suggest that the rare and unique combination of IFT88 alleles observed in this study provide insight into the physiological role of IFT88 in humans and the likely mechanism underlying retinal pathology in the pedigree with IRD.


Asunto(s)
Ciliopatías/genética , Degeneración Retiniana/genética , Proteínas Supresoras de Tumor/genética , Secuenciación Completa del Genoma , Alelos , Sistemas CRISPR-Cas/genética , Ciliopatías/fisiopatología , Femenino , Edición Génica , Predisposición Genética a la Enfermedad , Células HeLa , Homocigoto , Humanos , Masculino , Persona de Mediana Edad , Mutación , Linaje , Retina/patología , Degeneración Retiniana/fisiopatología
20.
Drug Metab Dispos ; 46(8): 1106-1117, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29784728

RESUMEN

Metabolic phenotype can be affected by multiple factors, including allelic variation and interactions with inhibitors. Human CYP2D6 is responsible for approximately 20% of cytochrome P450-mediated drug metabolism but consists of more than 100 known variants; several variants are commonly found in the population, whereas others are quite rare. Four CYP2D6 allelic variants-three with a series of mutations distal to the active site (*34, *17-2, *17-3) and one ultra-metabolizer with mutations near the active site (*53), along with reference *1 and an active site mutant of *1 (Thr309Ala)-were expressed, purified, and studied for interactions with the typical substrates dextromethorphan and bufuralol and the inactivator SCH 66712. We found that *34, *17-2, and *17-3 displayed reduced enzyme activity and NADPH coupling while producing the same metabolites as *1, suggesting a possible role for Arg296 in NADPH coupling. A higher-activity variant, *53, displayed similar NADPH coupling to *1 but was less susceptible to inactivation by SCH 66712. The Thr309Ala mutant showed similar activity to that of *1 but with greatly reduced NADPH coupling. Overall, these results suggest that kinetic and metabolic analysis of individual CYP2D6 variants is required to understand their possible contributions to variable drug response and the complexity of personalized medicine.


Asunto(s)
Citocromo P-450 CYP2D6/genética , Dextrometorfano/metabolismo , Etanolaminas/metabolismo , Imidazoles/metabolismo , Mutación/genética , NADP/metabolismo , Pirimidinas/metabolismo , Alelos , Dominio Catalítico/genética , Citocromo P-450 CYP2D6/metabolismo , Humanos , Inactivación Metabólica , Cinética , Fenotipo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA