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1.
Analyst ; 148(21): 5366-5379, 2023 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-37702052

RESUMEN

Paracetamol overdose is a leading cause of acute liver failure that can prove fatal. Establishing paracetamol concentration accurately and quickly is critical. Current detection methods are invasive, time-consuming and/or expensive. Non-invasive, rapid and cost-effective techniques are urgently required. To address this challenge, a novel approach, called Paper-Arrow Mass Spectrometry (PA-MS) has been developed. This technique combines sample collection, extraction, enrichment, separation and ionisation onto a single paper strip, and the entire analysis process, from sample to result, can be carried out in less than 10 min requiring only 2 µL of raw human saliva. PA-MS achieved a LOQ of 185 ng mL-1, mean recovery of 107 ± 7%, mean accuracy of 11 ± 8% and precision ≤5% using four concentrations, and had excellent linearity (r2 = 0.9988) in the range of 0.2-200 µg mL-1 covering the treatment concentration range, surpassing the best-in-class methods currently available for paracetamol analysis. Furthermore, from a panel of human saliva samples, inter-individual variability was found to be <10% using this approach. This technique represents a promising tool for rapid and accurate emergency diagnosis.

2.
Analyst ; 148(19): 4677-4687, 2023 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-37697928

RESUMEN

Surface-enhanced Raman scattering (SERS) is a powerful technique for detecting trace amounts of analytes. However, the performance of SERS substrates depends on many variables including the enhancement factor, morphology, consistency, and interaction with target analytes. In this study, we investigated, for the first time, the use of electrospray deposition (ESD) combined with a novel ambient focusing DC ion funnel to deposit a high density of gold nanoparticles (AuNPs) to generate large-area, uniform substrates for highly sensitive SERS analysis. We found that the combination of ambient ion focusing with ESD facilitated high-density and intact deposition of non-spherical NPs. This also allowed us to take advantage of a polydisperse colloidal solution of AuNPs (consisting of nanospheres and nanorods), as confirmed by finite-difference time domain (FDTD) simulations. Our SERS substrate exhibited excellent capture capacity for model analyte molecules, namely 4-aminothiophenol (4-ATP) and Rhodamine 6G (R6G), with detection limits in the region of 10-11 M and a relative standard deviation of <6% over a large area (∼500 × 500 µm2). Additionally, we assessed the quantitative performance of our SERS substrate using the R6G probe molecule. The results demonstrated excellent linearity (R2 > 0.99) over a wide concentration range (10-4 M to 10-10 M) with a detection limit of 80 pM.

3.
Mikrochim Acta ; 190(6): 215, 2023 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-37171648

RESUMEN

The detection of biogenic amines released from degraded meats is an effective method for evaluating meat freshness. However, existing traditional methods like titration are deemed tedious, while the use of sophisticated analytical instruments is not amenable to field testing. Herein, a cyanostilbene-based fluorescent array was rapidly fabricated using macroarray synthesis on a cellulose paper surface to detect amines liberated from spoiled beef, fish, and chicken. The fluorescence changes of immobilized molecules from the interaction with gaseous amines were used to monitor changes in freshness levels. Thanks to the high-throughput nature of macroarray synthesis, a set of highly responsive molecules such as pyridinium and dicyanovinyl moieties were quickly revealed. Importantly, this method offers flexibility in sensing applications including (1) sensing by individual sensor molecules, where the fluorescence response correlated well with established titration methods, and (2) collective sensing whereby chemometric analysis was used to provide a cutoff of freshness with 73-100% accuracy depending on meat types. Overall, this study paves the way for a robust and cost-effective tool for monitoring meat freshness.


Asunto(s)
Aminas Biogénicas , Carne , Animales , Bovinos , Carne/análisis , Aminas Biogénicas/análisis , Colorantes , Peces , Pollos
4.
Trop Med Int Health ; 27(6): 564-573, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35411997

RESUMEN

OBJECTIVES: The objective was to compare COVID-19 outcomes in the Omicron-driven fourth wave with prior waves in the Western Cape, assess the contribution of undiagnosed prior infection to differences in outcomes in a context of high seroprevalence due to prior infection and determine whether protection against severe disease conferred by prior infection and/or vaccination was maintained. METHODS: In this cohort study, we included public sector patients aged ≥20 years with a laboratory-confirmed COVID-19 diagnosis between 14 November and 11 December 2021 (wave four) and equivalent prior wave periods. We compared the risk between waves of the following outcomes using Cox regression: death, severe hospitalisation or death and any hospitalisation or death (all ≤14 days after diagnosis) adjusted for age, sex, comorbidities, geography, vaccination and prior infection. RESULTS: We included 5144 patients from wave four and 11,609 from prior waves. The risk of all outcomes was lower in wave four compared to the Delta-driven wave three (adjusted hazard ratio (aHR) [95% confidence interval (CI)] for death 0.27 [0.19; 0.38]. Risk reduction was lower when adjusting for vaccination and prior diagnosed infection (aHR: 0.41, 95% CI: 0.29; 0.59) and reduced further when accounting for unascertained prior infections (aHR: 0.72). Vaccine protection was maintained in wave four (aHR for outcome of death: 0.24; 95% CI: 0.10; 0.58). CONCLUSIONS: In the Omicron-driven wave, severe COVID-19 outcomes were reduced mostly due to protection conferred by prior infection and/or vaccination, but intrinsically reduced virulence may account for a modest reduction in risk of severe hospitalisation or death compared to the Delta-driven wave.


Asunto(s)
COVID-19 , Técnicas de Laboratorio Clínico , SARS-CoV-2 , Adulto , COVID-19/diagnóstico , COVID-19/epidemiología , COVID-19/prevención & control , COVID-19/virología , Prueba de COVID-19 , Vacunas contra la COVID-19/administración & dosificación , Estudios de Cohortes , Femenino , Humanos , Masculino , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , Estudios Seroepidemiológicos , Sudáfrica/epidemiología , Adulto Joven
5.
Xenotransplantation ; 29(3): e12747, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35384085

RESUMEN

Although human islet transplantation has proven to provide clinical benefits, especially the near complete amelioration of hypoglycemia, the supply of human islets is limited and insufficient to meet the needs of all people that could benefit from islet transplantation. Porcine islets, secreting insulin nearly identical to that of human insulin, have been proposed as a viable supply of unlimited islets. Further, encapsulation of the porcine islets has been shown to reduce or eliminate the use of immunosuppressive therapy that would be required to prevent rejection of the foreign islet tissue. The goal of the current study was to determine the long-term safety and efficacy of agarose encapsulated porcine islets (macrobeads) in diabetic cynomolgus macaques, in a study emulating a proposed IND trial in which daily exogenous insulin therapy would be reduced by 50% with no loss of glucose regulation. Four of six animals implanted with macrobeads demonstrated ≥ 30% reduction in insulin requirements in year 1 of follow-up. Animals were followed for 2, 3.5, and 7.4 years with no serious adverse events, mortality or evidence of pathogen transmission. This study supports the continued pursuit of encapsulated porcine islet therapy as a promising treatment option for diabetes mellitus.


Asunto(s)
Diabetes Mellitus Experimental , Trasplante de Islotes Pancreáticos , Animales , Diabetes Mellitus Experimental/terapia , Humanos , Insulina/uso terapéutico , Macaca , Porcinos , Trasplante Heterólogo
6.
Surg Endosc ; 36(11): 8255-8260, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35474390

RESUMEN

BACKGROUND: The use of the magnetic sphincter augmentation (MSA) in patients with de novo or persistent gastroesophageal reflux disease (GERD) after sleeve gastrectomy has not been thoroughly investigated. OBJECTIVE: The aim of this study is to evaluate the efficacy of MSA device placement in improving GERD symptoms and reducing anti-reflux medication usage in patients with persistent or de novo GERD after sleeve gastrectomy. METHODS: This is a retrospective analysis of patients who underwent laparoscopic MSA device placement between January 2018 and July 2020 after sleeve gastrectomy. RESULTS: A total of twenty-two patients met inclusion criteria. Twenty patients were female (91%) and two patients were male (9%). All patients were taking anti-reflux medications daily to control GERD symptoms prior to MSA device placement. There was a significant improvement in the mean GERD-HRQL survey scores when comparing scores prior to (43.8) and after (16.7) MSA device placement (p < 0.0001). Majority of the patients did well without any post-operative complications (77%). Nearly 82% of patients were no longer taking any anti-acid medications after MSA device placement (p < 0.0485). There were no patients that required MSA device removals. There were no adverse events such as MSA device erosions or device-related mortalities. CONCLUSIONS: MSA device placement in patients with medically refractory GERD after sleeve gastrectomy is a safe and viable alternative to Roux-en-Y gastric bypass without conferring additional risks. We show an improvement in reflux symptoms after MSA device placement as evidenced by decreased post-operative GERD-HRQL scores, decreased anti-acid medication usage, and overall patient satisfaction with the procedure. Further prospective and comparative studies with longer term follow-up are needed to validate the use of MSA in patients who have undergone sleeve gastrectomy.


Asunto(s)
Reflujo Gastroesofágico , Laparoscopía , Obesidad Mórbida , Masculino , Femenino , Humanos , Estudios Retrospectivos , Calidad de Vida , Reflujo Gastroesofágico/etiología , Reflujo Gastroesofágico/cirugía , Gastrectomía/efectos adversos , Gastrectomía/métodos , Laparoscopía/efectos adversos , Fenómenos Magnéticos , Resultado del Tratamiento , Obesidad Mórbida/cirugía
7.
J Phycol ; 57(5): 1492-1503, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33960400

RESUMEN

One previously unstudied aspect of differences between sexual and asexual life stages in large-scale transport and accumulation is density (mass per unit volume) of cells in each life stage. The specific density was determined for Scrippsiella lachrymosa cells in medium with and without nitrogen (N) enrichment through density-gradient centrifugation. Growth medium without N addition is often called "encystment medium" when used for the purpose of resting cyst formation in cyst-forming dinoflagellates; mating gametes are usually seen after 2-3 days. Significant differences in specific density were found after 2 days in encystment medium simultaneously with the observation of typical gamete swimming behavior and mating. The specific density of cells in encystment medium was 1.06 g · cm-3 ; whereas, the specific density of cells in growth medium was 1.11 g · cm-3 . Cells in encystment medium were found to have significantly increased lipid content, reduced chlorophyll content, and reduced internal complexity. The findings may explain differential transport of less dense and chemotactically aggregating gametes into surface blooms in contrast to denser vegetative cells that perform daily vertical migration and do not aggregate. Passive accumulation of non-migrating gametes into layers in stagnant water also can be explained, as well as sinking of zygotes when the storage of highly dense starch increases. Resting cysts had a density of over 1.14 g · cm-3 and would sink to become part of the silt fraction of the sediment. We suggest that differences in behavior and buoyancy between sexual and asexual life stages cause differences in cell accumulation, and therefore large-scale, environmental transport could be directly dependent upon life-cycle transitions.


Asunto(s)
Dinoflagelados , Animales , Clorofila , Hidrodinámica , Estadios del Ciclo de Vida , Cigoto
8.
Cogn Process ; 22(Suppl 1): 77-87, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34448970

RESUMEN

This paper is in two parts. Part 1 examines the phenomenon of making space as a process involving one or other kind of legal decision-making, for example when a state authority authorizes the creation of a new highway along a certain route or of a new park in a certain location. In cases such as this, a new abstract spatial entity comes into existence - the route, the boundaries of the area to be set aside for the park - followed only later by concordant changes in physical reality. In Part 2, we show that features identified in studying this phenomenon of legal spacemaking can be detected in other spheres of human activity, for example in planning (where spacemaking is projected into the future), and in reasoning about history (where spacemaking is projected back through time). We shall see that these features display themselves in especially complex ways in our everyday use of language, and we conclude by examining the implications of this complexity for attempts to create an artificial intelligence that would enjoy a mastery of language that would be equivalent to that of human beings.


Asunto(s)
Inteligencia Artificial , Actividades Humanas , Cognición , Humanos
9.
Anal Chem ; 92(13): 9104-9112, 2020 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-32479060

RESUMEN

This paper describes, in detail, the development of a novel, low-cost, and flexible drift tube (DT) along with an associated ion mobility spectrometer system. The DT is constructed from a flexible printed circuit board (PCB), with a bespoke "dog-leg" track design, that can be rolled up for ease of assembly. This approach incorporates a shielding layer, as part of the flexible PCB design, and represents the minimum dimensional footprint conceivable for a DT. The low thermal mass of the polyimide substrate and overlapping electrodes, as afforded by the dog-leg design, allow for efficient heat management and high field linearity within the tube-achieved from a single PCB. This is further enhanced by a novel double-glazing configuration which provides a simple and effective means for gas management, minimizing thermal variation within the assembly. Herein, we provide a full experimental characterization of the flexible DT ion mobility spectrometer (Flex-DT-IMS) with corresponding electrodynamic (Simion 8.1) and fluid dynamic (SolidWorks) simulations. The Flex-DT-IMS is shown to have a resolution >80 and a detection limit of low nanograms for the analysis of common explosives (RDX, PETN, HMX, and TNT).

10.
Opt Express ; 28(20): 29590-29618, 2020 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-33114856

RESUMEN

Calculations of X-ray wave propagation in large objects are needed for modeling diffractive X-ray optics and for optimization-based approaches to image reconstruction for objects that extend beyond the depth of focus. We describe three methods for calculating wave propagation with large arrays on parallel computing systems with distributed memory: (1) a full-array Fresnel multislice approach, (2) a tiling-based short-distance Fresnel multislice approach, and (3) a finite difference approach. We find that the first approach suffers from internode communication delays when the transverse array size becomes large, while the second and third approaches have similar scaling to large array size problems (with the second approach offering about three times the compute speed).

11.
Philos Trans A Math Phys Eng Sci ; 378(2166): 20190053, 2020 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-31955673

RESUMEN

Sparse solvers provide essential functionality for a wide variety of scientific applications. Highly parallel sparse solvers are essential for continuing advances in high-fidelity, multi-physics and multi-scale simulations, especially as we target exascale platforms. This paper describes the challenges, strategies and progress of the US Department of Energy Exascale Computing project towards providing sparse solvers for exascale computing platforms. We address the demands of systems with thousands of high-performance node devices where exposing concurrency, hiding latency and creating alternative algorithms become essential. The efforts described here are works in progress, highlighting current success and upcoming challenges. This article is part of a discussion meeting issue 'Numerical algorithms for high-performance computational science'.

12.
Nucleic Acids Res ; 46(D1): D1168-D1180, 2018 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-29186578

RESUMEN

The Planteome project (http://www.planteome.org) provides a suite of reference and species-specific ontologies for plants and annotations to genes and phenotypes. Ontologies serve as common standards for semantic integration of a large and growing corpus of plant genomics, phenomics and genetics data. The reference ontologies include the Plant Ontology, Plant Trait Ontology and the Plant Experimental Conditions Ontology developed by the Planteome project, along with the Gene Ontology, Chemical Entities of Biological Interest, Phenotype and Attribute Ontology, and others. The project also provides access to species-specific Crop Ontologies developed by various plant breeding and research communities from around the world. We provide integrated data on plant traits, phenotypes, and gene function and expression from 95 plant taxa, annotated with reference ontology terms. The Planteome project is developing a plant gene annotation platform; Planteome Noctua, to facilitate community engagement. All the Planteome ontologies are publicly available and are maintained at the Planteome GitHub site (https://github.com/Planteome) for sharing, tracking revisions and new requests. The annotated data are freely accessible from the ontology browser (http://browser.planteome.org/amigo) and our data repository.


Asunto(s)
Bases de Datos Genéticas , Genoma de Planta , Plantas/genética , Productos Agrícolas/genética , Curaduría de Datos , Regulación de la Expresión Génica de las Plantas , Ontología de Genes , Anotación de Secuencia Molecular , Fenotipo , Programas Informáticos , Interfaz Usuario-Computador
13.
Can Assoc Radiol J ; 71(2): 217-225, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32062992

RESUMEN

PURPOSE: The aim of our study was to compare whole-body diffusion-weighted MRI (WB-DWI-MRI) to fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the assessment of initial staging and treatment response in pediatric patients with Hodgkin lymphoma. MATERIALS AND METHODS: This prospective study comprised 11 children with Hodgkin lymphoma. Whole-body DWI-MRI and FDG-PET/CT were obtained at baseline and after 2 cycles of chemotherapy. Two radiologists measured the apparent diffusion coefficient (ADC) values of the sites of involvement agreed upon in consensus and 1 nuclear medicine physician assessed the PET/CT. Reliability of radiologists' ratings was assessed by intraclass correlation coefficients (ICC2,1). The sensitivity and positive predictive value (PPV) of DW-MRI relative to PET/CT were calculated for nodal and extranodal sites. The patients were staged according to both modalities. Association of treatment responses was assessed through the Pearson correlation between the ADC ratios and the change standardized uptake value (SUV) between baseline and follow-up. RESULTS: There was good agreement between the raters for nodal and extranodal ADC measurements. The sensitivity and PPV of DW-MRI relative to PET/CT of nodal disease was 0.651 and 1.0, respectively, at baseline, and 0.697 and 0.885 at follow-up. The sensitivity and PPV of extranodal disease were 0.545 and 0.6 at baseline, and 0.167 and 0.333 at follow-up. Diffusion-weighted MRI determined correct tumor stage in 8 of 11 examinations. There was poor correlation between the ADC ratios and the absolute change in SUV between baseline and follow-up (0.348). CONCLUSION: Our experience showed that WB-DWI-MRI is inferior to PET/CT for initial staging and assessment of treatment response of Hodgkin lymphoma in pediatric patients.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Enfermedad de Hodgkin/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones , Imagen de Cuerpo Entero/métodos , Adolescente , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Niño , Femenino , Fluorodesoxiglucosa F18 , Enfermedad de Hodgkin/tratamiento farmacológico , Enfermedad de Hodgkin/patología , Humanos , Ganglios Linfáticos/diagnóstico por imagen , Masculino , Estadificación de Neoplasias , Variaciones Dependientes del Observador , Valor Predictivo de las Pruebas , Estudios Prospectivos , Radiofármacos , Reproducibilidad de los Resultados
14.
Nucleic Acids Res ; 45(D1): D339-D346, 2017 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-27899649

RESUMEN

The Protein Ontology (PRO; http://purl.obolibrary.org/obo/pr) formally defines and describes taxon-specific and taxon-neutral protein-related entities in three major areas: proteins related by evolution; proteins produced from a given gene; and protein-containing complexes. PRO thus serves as a tool for referencing protein entities at any level of specificity. To enhance this ability, and to facilitate the comparison of such entities described in different resources, we developed a standardized representation of proteoforms using UniProtKB as a sequence reference and PSI-MOD as a post-translational modification reference. We illustrate its use in facilitating an alignment between PRO and Reactome protein entities. We also address issues of scalability, describing our first steps into the use of text mining to identify protein-related entities, the large-scale import of proteoform information from expert curated resources, and our ability to dynamically generate PRO terms. Web views for individual terms are now more informative about closely-related terms, including for example an interactive multiple sequence alignment. Finally, we describe recent improvement in semantic utility, with PRO now represented in OWL and as a SPARQL endpoint. These developments will further support the anticipated growth of PRO and facilitate discoverability of and allow aggregation of data relating to protein entities.


Asunto(s)
Biología Computacional/métodos , Bases de Datos Genéticas , Proteínas , Animales , Humanos , Proteínas/química , Proteínas/genética , Navegador Web
15.
Anal Chem ; 90(15): 9353-9358, 2018 08 07.
Artículo en Inglés | MEDLINE | ID: mdl-29975501

RESUMEN

It is well-known that 2D dried blood spots on paper offer a facile sample collection, storage, and transportation of blood. However, large volume requirements, possible analyte instability, and difficult sample recovery plague this method, lowering confidence in analyte quantification. For the first time, we demonstrate a new approach using 3D dried blood spheroids for stabilization of small volume blood samples, mitigating these effects without cold storage. Blood spheroids form on hydrophobic paper, preventing interaction between the sample and paper substrate, eliminating all chromatographic effects. Stability of the enzyme alanine transaminase and labile organic compounds such as cocaine and diazepam were also shown to increase in the spheroid by providing a critical radius of insulation. On-surface analysis of the dried blood spheroids using paper spray mass spectrometry resulted in sub-ng/mL limits of detection for all illicit drugs tested, representing 1 order of magnitude improvement compared with analysis from 2D dried blood spots.


Asunto(s)
Pruebas con Sangre Seca/métodos , Temperatura , Alanina Transaminasa/sangre , Cocaína/sangre , Diazepam/sangre , Estabilidad de Enzimas , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Límite de Detección
16.
BMC Cancer ; 18(1): 1217, 2018 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-30514247

RESUMEN

BACKGROUND: Agarose encapsulated murine renal adenocarcinoma cells (RENCA macrobeads) are currently being investigated in clinical trials as a treatment for therapy-resistant metastatic colorectal cancer. We have previously demonstrated the capacity of RENCA macrobeads to produce diffusible substances that markedly inhibit the proliferation of epithelial-derived tumor cells outside the macrobead environment. This study examined the molecular mechanisms underlying the observed inhibition in targeted tumor cells exposed to RENCA macrobeads. METHODS: We evaluated changes in transcription factor responses, participating intracellular signaling pathways and the involvement of specific cellular receptors in targeted tumor cells exposed to RENCA macrobeads. RESULTS: Factors secreted by RENCA macrobeads significantly up-regulated the activity of the MEF2 transcription factor as well as altered the transcription of MEF2b and MEF2d isoforms in targeted tumor cells. Suppression of individual or multiple MEF2 isoforms in target tumor cells markedly reduced the growth inhibitory effects of RENCA macrobeads. Furthermore, these effects were linked to the activation of the EGF receptor as attenuation of EGFR resulted in a substantial reduction of the cancer cell growth-inhibitory effect. CONCLUSIONS: Since interruption of the EGFR signaling cascade did not eliminate RENCA macrobead-induced growth control, our data suggests that RENCA macrobeads exert their full growth inhibitory effects through the simultaneous activation of multiple signaling pathways. In contrast to a precision medicine approach targeting single molecular abnormalities, the RENCA macrobead functions as a biological-systems therapy to re-establish regulation in a highly dysfunctional and dysregulated cancer system.


Asunto(s)
Carcinoma de Células Renales/metabolismo , Neoplasias Renales/metabolismo , Microesferas , Transducción de Señal/fisiología , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Receptores ErbB/metabolismo , Gefitinib/farmacología , Humanos , Factores de Transcripción MEF2/fisiología , Ratones , Ratones Endogámicos BALB C , Transducción de Señal/efectos de los fármacos
17.
Xenotransplantation ; 25(6): e12443, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30054944

RESUMEN

BACKGROUND: Allogeneic islet transplantation for the treatment of type 1 diabetes often requires multiple implant procedures, from as many as several human pancreas donors, to achieve lasting clinical benefit. Given the limited availability of human pancreases for islet isolation, porcine islets have long been considered a potential option for clinical use. Agarose-encapsulated porcine islets (macrobeads) permit long-term culture and thus a thorough evaluation of microbiological safety and daily insulin secretory capacity, prior to implantation. The goal of this study was the development of a method for determining an effective dose of encapsulated islets based on their measured in vitro insulin secretion in a preclinical model of type 1 diabetes. METHODS: Spontaneously diabetic BioBreeding diabetes-prone rats were implanted with osmotic insulin pumps in combination with continuous glucose monitoring to establish the daily insulin dose required to achieve continuous euglycaemia in individual animals. Rats were then implanted with a 1×, 2× or 3× dose (defined as the ratio of macrobead in vitro insulin secretion per 24 hours to the recipient animal's total daily insulin requirement) of porcine islet macrobeads, in the absence of immunosuppression. In vivo macrobead function was assessed by recipient non-fasted morning blood glucose values, continuous glucose monitoring and the presence of peritoneal porcine C-peptide. At the end of the study, the implanted macrobeads were removed and returned to in vitro culture for the evaluation of insulin secretion. RESULTS: Diabetic rats receiving a 2× macrobead implant exhibited significantly improved blood glucose regulation compared to that of rats receiving a 1× dose during a 30-day pilot study. In a 3-month follow-up study, 2× and 3× macrobead doses initially controlled blood glucose levels equally well, although several animals receiving a 3× dose maintained euglycaemia throughout the study, compared to none of the 2× animals. The presence of porcine C-peptide in rat peritoneal fluid 3 months post-implant and the recurrence of hyperglycaemia following macrobead removal, along with the finding of persistent in vitro insulin secretion from retrieved macrobeads, confirmed long-term graft function. CONCLUSIONS: Increasing dosages of islet macrobeads transplanted into diabetic rats, based on multiples of in vitro insulin secretion matched to the recipient's exogenous insulin requirements, correlated with improved blood glucose regulation and increased duration of graft function. These results demonstrate the usefulness of a standardized model for the evaluation of the functional effectiveness of islets intended for transplantation, in this case using intraperitoneally implanted agarose macrobeads, in diabetic rats. The results suggest that some features of this islet-dosing methodology may be applicable, and indeed necessary, to clinical allogeneic and xenogeneic islet transplantation.


Asunto(s)
Secreción de Insulina/fisiología , Insulina/biosíntesis , Trasplante de Islotes Pancreáticos , Islotes Pancreáticos/metabolismo , Animales , Automonitorización de la Glucosa Sanguínea/métodos , Diabetes Mellitus Experimental/sangre , Trasplante de Islotes Pancreáticos/métodos , Proyectos Piloto , Trasplante Heterólogo/métodos
18.
Ecotoxicology ; 27(5): 539-555, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29623614

RESUMEN

The concept of the Anthropocene, that humans are now re-engineering global ecosystems, is in part evidenced by the pervasive pollution by persistent organic pollutants (POPs). Certain POPs are hormone mimics and can disrupt endocrine and hence reproductive processes, shown mainly by laboratory studies with model species. There are, in contrast, fewer confirmations of such disruption from eco-epidemiological studies of wild mammals. Here we used the American mink (Neovison vison) as a sentinel species for such a study. Over the period 1998-2006, 161 mink carcasses were obtained from commercial trappers in the Canadian provinces of British Columbia and Ontario. Mink were aged, sexed, measured, and body condition assessed. Livers were analyzed either individually or pooled for organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and subsets for polybrominated diphenyl ethers (PBDEs). We primarily addressed whether contaminants affected male reproductive development by measuring baculum size and assessing the influences of age and body condition. We also considered the influence of spatial variation on relative exposure and size of baculum. Statistical models separated by age class revealed that significant relationships between baculum length or mass and juvenile mink were mostly positive, whereas for adults and first year mink they were mostly negative. A significant negative relationship for adult mink was determined between DDE and both baculum length and mass. For juvenile mink we found significant positive relationships between ∑PCBs, DDE and ∑PBDEs with baculum length. Our results provide some indication of negative effects of halogenated contaminants on male reproductive development in wild mink, and the most likely candidate chemical is the confirmed anti-androgenic compound, DDE, rather than PCBs or other compounds.


Asunto(s)
Exposición a Riesgos Ambientales , Contaminantes Ambientales/efectos adversos , Visón/metabolismo , Reproducción/efectos de los fármacos , Factores de Edad , Animales , Composición Corporal/efectos de los fármacos , Colombia Británica , Monitoreo del Ambiente , Éteres Difenilos Halogenados/efectos adversos , Hidrocarburos Clorados/efectos adversos , Masculino , Ontario , Tamaño de los Órganos/efectos de los fármacos , Plaguicidas/efectos adversos , Bifenilos Policlorados/efectos adversos
19.
Chin J Cancer Res ; 30(1): 72-83, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29545721

RESUMEN

OBJECTIVE: The complexity, heterogeneity and capacity of malignant neoplastic cells and tumors for rapid change and evolution suggest that living-cell-based biological-systems approaches to cancer treatment are merited. Testing this hypothesis, the tumor marker, metabolic activity, and overall survival (OS) responses, to the use of one such system, implantable macrobeads [RENCA macrobeads (RMBs)], in phase I and IIa clinical trials in advanced, treatment-resistant metastatic colorectal cancer (mCRC) are described here. METHODS: Forty-eight mCRC patients (30 females; 18 males), who had failed all available, approved treatments, underwent RMB implantation (8 RMB/kg body weight) up to 4 times in phase I and phase IIa open-label trials. Physicals, labs [tumor and inflammation markers, lactate dehydrogenase (LDH)] and positron emission tomography-computed tomography (PET-CT) imaging to measure number/volume and metabolic activity of the tumors were performed pre- and 3-month-post-implantation to evaluate safety and initial efficacy (as defined by biological responses). PET-CT maximum standard uptake value (SUVmax) (baseline and d 90; SUVmax ≥2.5), LDH, and carcinoembryonic antigen (CEA) and/or cancer antigen 19-9 (CA 19-9) response (baseline, d 30 and/or d 60) were assessed and compared to OS. RESULTS: Responses after implantation were characterized by an at least 20% decrease in CEA and/or CA 19-9 in 75% of patients. Fluorodeoxyglucose (FDG)-positive lesions (phase I, 39; 2a, 82) were detected in 37/48 evaluable patients, with 35% stable volume and stable or decreased SUV (10) plus four with necrosis; 10, increased tumor volume, SUV. LDH levels remained stable and low in Responders (R) (d 0-60, 290.4-333.9), but increased steadily in Non-responders (NR) (d 0-60, 382.8-1,278.5) (d 60, P=0.050). Responders to RMBs, indicated by the changes in the above markers, correlated with OS (R mean OS=10.76 months; NR mean OS=4.9 months; P=0.0006). CONCLUSIONS: The correlations of the tumor marker, tumor volume and SUV changes on PET-CT, and LDH levels themselves, and with OS, support the concept of a biological response to RMB implantation and the validity of the biological-systems approach to mCRC. A phase III clinical trial is planned.

20.
Genet Med ; 19(3): 345-351, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27632687

RESUMEN

PURPOSE: He Tangata Kei Tua, a relationship model for biobanks, was developed to facilitate best practice in addressing Maori ethical concerns by guiding culturally informed policy and practice for biobanks in relation to governance, operational, and community engagement activities. METHODS: The model is based on key issues of relevance to Maori that were identified as part of the Health Research Council of New Zealand-funded research project, Te Mata Ira (2012-2015). RESULTS: This project identified Maori perspectives on biobanking and genetic research, and along with tikanga Maori it developed cultural guidelines for ethical biobanking and genetic research involving biospecimens. The model draws on a foundation of matauranga (Indigenous knowledge) and tikanga Maori (Maori protocols and practices) and will be useful for biobanks, researchers, ethics committee members, and those who engage in consultation or advice about biobanking in local, regional, national, or international settings. CONCLUSION: This article describes the model and considers the policy and practice implications for biobanks seeking to address Maori ethical concerns. Although the model has focused on Maori aspirations in the New Zealand context, it provides a framework for considering cultural values in relation to other community or indigenous contexts.Genet Med 19 3, 345-351.


Asunto(s)
Bancos de Muestras Biológicas/ética , Participación de la Comunidad/métodos , Competencia Cultural/ética , Investigación Genética/ética , Nativos de Hawái y Otras Islas del Pacífico/genética , Investigación Biomédica/ética , Femenino , Genómica/ética , Humanos , Masculino , Nueva Zelanda , Grupos de Población , Investigadores/ética
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