Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 64
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Diabetologia ; 67(3): 528-546, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38127123

RESUMEN

AIMS/HYPOTHESIS: Diabetes mellitus is associated with impaired insulin secretion, often aggravated by oversecretion of glucagon. Therapeutic interventions should ideally correct both defects. Glucagon-like peptide 1 (GLP-1) has this capability but exactly how it exerts its glucagonostatic effect remains obscure. Following its release GLP-1 is rapidly degraded from GLP-1(7-36) to GLP-1(9-36). We hypothesised that the metabolite GLP-1(9-36) (previously believed to be biologically inactive) exerts a direct inhibitory effect on glucagon secretion and that this mechanism becomes impaired in diabetes. METHODS: We used a combination of glucagon secretion measurements in mouse and human islets (including islets from donors with type 2 diabetes), total internal reflection fluorescence microscopy imaging of secretory granule dynamics, recordings of cytoplasmic Ca2+ and measurements of protein kinase A activity, immunocytochemistry, in vivo physiology and GTP-binding protein dissociation studies to explore how GLP-1 exerts its inhibitory effect on glucagon secretion and the role of the metabolite GLP-1(9-36). RESULTS: GLP-1(7-36) inhibited glucagon secretion in isolated islets with an IC50 of 2.5 pmol/l. The effect was particularly strong at low glucose concentrations. The degradation product GLP-1(9-36) shared this capacity. GLP-1(9-36) retained its glucagonostatic effects after genetic/pharmacological inactivation of the GLP-1 receptor. GLP-1(9-36) also potently inhibited glucagon secretion evoked by ß-adrenergic stimulation, amino acids and membrane depolarisation. In islet alpha cells, GLP-1(9-36) led to inhibition of Ca2+ entry via voltage-gated Ca2+ channels sensitive to ω-agatoxin, with consequential pertussis-toxin-sensitive depletion of the docked pool of secretory granules, effects that were prevented by the glucagon receptor antagonists REMD2.59 and L-168049. The capacity of GLP-1(9-36) to inhibit glucagon secretion and reduce the number of docked granules was lost in alpha cells from human donors with type 2 diabetes. In vivo, high exogenous concentrations of GLP-1(9-36) (>100 pmol/l) resulted in a small (30%) lowering of circulating glucagon during insulin-induced hypoglycaemia. This effect was abolished by REMD2.59, which promptly increased circulating glucagon by >225% (adjusted for the change in plasma glucose) without affecting pancreatic glucagon content. CONCLUSIONS/INTERPRETATION: We conclude that the GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of glucagon secretion. We propose that the increase in circulating glucagon observed following genetic/pharmacological inactivation of glucagon signalling in mice and in people with type 2 diabetes reflects the removal of GLP-1(9-36)'s glucagonostatic action.


Asunto(s)
Diabetes Mellitus Tipo 2 , Hipoglucemia , Islotes Pancreáticos , Fragmentos de Péptidos , Humanos , Glucagón/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Péptido 1 Similar al Glucagón/metabolismo , Islotes Pancreáticos/metabolismo , Hipoglucemia/metabolismo , Insulina/metabolismo
2.
New Phytol ; 240(2): 676-693, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37545368

RESUMEN

Reactive carbonyl species (RCS) derived from lipid peroxides can act as critical damage or signaling mediators downstream of reactive oxygen species by modifying target proteins. However, their biological effects and underlying mechanisms remain largely unknown in plants. Here, we have uncovered the mechanism by which the RCS 4-hydroxy-(E)-2-nonenal (HNE) participates in photosystem II (PSII) repair cycle of chloroplasts, a crucial process for maintaining PSII activity under high and changing light conditions. High Light Sensitive 1 (HLT1) is a potential NADPH-dependent reductase in chloroplasts. Deficiency of HLT1 had no impact on the growth of Arabidopsis plants under normal light conditions but increased sensitivity to high light, which resulted from a defective PSII repair cycle. In hlt1 plants, the accumulation of HNE-modified D1 subunit of PSII was observed, which did not affect D1 degradation but hampered the dimerization of repaired PSII monomers and reassembly of PSII supercomplexes on grana stacks. HLT1 is conserved in all photosynthetic organisms and has functions in overall growth and plant fitness in both Arabidopsis and rice under naturally challenging field conditions. Our work provides the mechanistic basis underlying RCS scavenging in light acclimation and suggests a potential strategy to improve plant productivity by manipulating RCS signaling in chloroplasts.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Cloroplastos/metabolismo , Tilacoides/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Aclimatación , Luz
3.
Reprod Biol Endocrinol ; 21(1): 24, 2023 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-36869381

RESUMEN

BACKGROUND: Polycystic ovarian syndrome (PCOS) is one of the most common causes of infertility in reproductive-age women. However, the efficacy and optimal therapeutic strategy for reproductive outcomes are still under debate. We conducted a systematic review and network meta-analysis to compare the efficacy of different first-line pharmacological therapies in terms of reproductive outcomes for women with PCOS and infertility. METHODS: A systematic retrieval of databases was conducted, and randomized clinical trials (RCTs) of pharmacological interventions for infertile PCOS women were included. The primary outcomes were clinical pregnancy and live birth, and the secondary outcomes were miscarriage, ectopic pregnancy and multiple pregnancy. A network meta-analysis based on a Bayesian model was performed to compare the effects of the pharmacological strategies. RESULTS: A total of 27 RCTs with 12 interventions were included, and all therapies tended to increase clinical pregnancy, especially pioglitazone (PIO) (log OR 3.14, 95% CI 1.56 ~ 4.70, moderate confidence), clomiphene citrate (CC) + exenatide (EXE) (2.96, 1.07 ~ 4.82, moderate confidence) and CC + metformin (MET) + PIO (2.82, 0.99 ~ 4.60, moderate confidence). Moreover, CC + MET + PIO (2.8, -0.25 ~ 6.06, very low confidence) could increase live birth most when compared to placebo, even without a significant difference. For secondary outcomes, PIO showed a tendency to increase miscarriage (1.44, -1.69 ~ 5.28, very low confidence). MET (-11.25, -33.7 ~ 0.57, low confidence) and LZ + MET (-10.44, -59.56 ~ 42.11, very low confidence) were beneficial for decreasing ectopic pregnancy. MET (0.07, -4.26 ~ 4.34, low confidence) showed a neutral effect in multiple pregnancy. Subgroup analysis demonstrated no significant difference between these medications and placebo in obese participants. CONCLUSIONS: Most first-line pharmacological treatments were effective in improving clinical pregnancy. CC + MET + PIO should be recommended as the optimal therapeutic strategy to improve pregnancy outcomes. However, none of the above treatments had a beneficial effect on clinical pregnancy in obese PCOS. TRIAL REGISTRATION: CRD42020183541; 05 July 2020.


Asunto(s)
Aborto Espontáneo , Infertilidad Femenina , Metformina , Síndrome del Ovario Poliquístico , Femenino , Embarazo , Humanos , Metaanálisis en Red , Clomifeno , Nacimiento Vivo , Obesidad , Pioglitazona , Ensayos Clínicos Controlados Aleatorios como Asunto
4.
Clin Genet ; 102(3): 228-233, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35599441

RESUMEN

Hypokalemia is a common disorder in clinical settings; however, nonmolecular diagnostic testing cannot explain some causes of hypokalemia. To determine the etiology of clinically unexplained hypokalemia without hypertension (CUHypoNH) and to obtain a diagnostic yield of monogenic hypokalemia without hypertension in adults (MHNHA), we enrolled 82 patients with CUHypoNH for whole-exome sequencing or targeted gene sequencing of genes associated with 4000 monogenic disorders. Through molecular diagnosis, 25 patients were diagnosed with monogenic hypokalemia, and a diagnostic yield of 30.5% was obtained. Among patients with MHNHA, 18 patients (18/82, 22.0% and 72% of MHNHA) with Gitelman syndrome accounted for the largest proportion. Among the 29 diagnostic variants found, eight mutations have not been reported previously; these include three point mutations, one frameshift mutation, and four exon deletions. Based on the clinical presentation of patients with CUHypoNH, the diagnostic yield of monogenic hypokalemia was the highest for chronic asymptomatic hypokalemia (8/11, 72.7%). Twenty-one patients had concomitant hypomagnesemia, when accompanied with hypocalciuria, the molecular diagnostic yield of Gitelman syndrome increased to 88.2%. Overall, this study on hospitalized adult patients explored the etiology of CUHypoNH using high-throughput sequencing. Molecular diagnosis of CUHypoNH is clinically significant in guiding precision treatment and improving disease prognosis.


Asunto(s)
Síndrome de Gitelman , Hipertensión , Hipopotasemia , Adulto , Síndrome de Gitelman/complicaciones , Síndrome de Gitelman/diagnóstico , Síndrome de Gitelman/genética , Humanos , Hipertensión/diagnóstico , Hipertensión/genética , Hipopotasemia/complicaciones , Hipopotasemia/diagnóstico , Hipopotasemia/genética , Mutación , Miembro 3 de la Familia de Transportadores de Soluto 12/genética
5.
Ecotoxicol Environ Saf ; 243: 113964, 2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-35994903

RESUMEN

To monitor environmental water pollution effectively and meet human water needs, it is crucial to develop a fast, simple, and accurate method for monitoring chemical oxygen demand (COD) in various water systems. In this study, COD prediction models for different water systems were developed by combining near-infrared (NIR) spectroscopy with partial least squares regression (PLSR). Samples of wastewater, surface water, and seawater were collected from Guangzhou, Guangdong Province, China. Three pretreatment methods were used to preprocess the spectra in order to improve the accuracy and minimalism of the model. We investigate the performance of two variable selection algorithms, namely, binary gray wolf optimization (BGWO) and competitive adaptive reweighting sampling (CARS). The results show that both BGWO and CARS improved the performance of the model in terms of higher accuracy and less wavelength input; both of the combined model performances were better than that of PLSR alone, and CARS-PLSR achieved the best results. Using CARS-PLSR, surface water, wastewater, and seawater model inputs were reduced by 96 %, 96 %, and 82 % as compared to the PLSR results, respectively, and the testing sets R2 reached 0.860, 0.815, and 0.692, respectively. The spectral variable selection algorithm could identify the important spectral variables between COD content and NIR spectra in three water systems, thereby improving the accuracy and simplicity of the PLSR model for COD prediction. Our results have important practical value for predicting COD content in different water systems by NIR spectroscopy.


Asunto(s)
Espectroscopía Infrarroja Corta , Agua , Algoritmos , Análisis de la Demanda Biológica de Oxígeno , Humanos , Análisis de los Mínimos Cuadrados , Espectroscopía Infrarroja Corta/métodos , Aguas Residuales
6.
Proc Natl Acad Sci U S A ; 113(38): 10708-13, 2016 09 20.
Artículo en Inglés | MEDLINE | ID: mdl-27601637

RESUMEN

Light is a major environmental factor regulating flowering time, thus ensuring reproductive success of higher plants. In contrast to our detailed understanding of light quality and photoperiod mechanisms involved, the molecular basis underlying high light-promoted flowering remains elusive. Here we show that, in Arabidopsis, a chloroplast-derived signal is critical for high light-regulated flowering mediated by the FLOWERING LOCUS C (FLC). We also demonstrate that PTM, a PHD transcription factor involved in chloroplast retrograde signaling, perceives such a signal and mediates transcriptional repression of FLC through recruitment of FVE, a component of the histone deacetylase complex. Thus, our data suggest that chloroplasts function as essential sensors of high light to regulate flowering and adaptive responses by triggering nuclear transcriptional changes at the chromatin level.


Asunto(s)
Proteínas de Arabidopsis/genética , Proteínas Portadoras/genética , Flores/genética , Proteínas de Dominio MADS/genética , Dedos de Zinc PHD/genética , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Núcleo Celular/genética , Núcleo Celular/efectos de la radiación , Cloroplastos/genética , Cloroplastos/metabolismo , Cromatina/genética , Cromatina/efectos de la radiación , Flores/crecimiento & desarrollo , Flores/efectos de la radiación , Regulación de la Expresión Génica de las Plantas/efectos de la radiación , Histona Desacetilasas/genética , Luz , Transducción de Señal/genética , Factores de Transcripción
7.
AAPS PharmSciTech ; 18(3): 913-919, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27401333

RESUMEN

The objective of this paper is to develop an easy and fast near-infrared spectroscopy (NIRS) assay for the four key quality-indicative active ingredients of Tongkang tablets by comparing the true content of the active ingredients measured by high performance liquid chromatography (HPLC) and the NIRS data. The HPLC values for the active ingredients content of Cimicifuga glycoside, calycosin glucoside, 5-O-methylvisamminol and hesperidin in Tongkang tablets were set as reference values. The NIRS raw spectra of Tongkang tablets were processed using first-order convolution method. The iterative optimization method was chosen to optimize the band for Cimicifuga glycoside and 5-O-methylvisamminol, and correlation coefficient method was used to determine the optimal band of calycosin glucoside and hesperidin. A near-infrared quantitative calibration model was established for each quality-indicative ingredient by partial least-squares method on the basis of the contents detected by HPLC and the obtained NIRS spectra. The correlation coefficient R 2 values of the four models of Cimicifuga glycoside, calycosin glucoside, 5-O-methylvisamminol and hesperidin were 0.9025, 0.8582, 0.9250, and 0.9325, respectively. It was demonstrated that the accuracy of the validation values was approximately 90% by comparison of the predicted results from NIRS models and the HPLC true values, which suggested that NIRS assay was successfully established and validated. It was expected that the quantitative analysis models of the four indicative ingredients could be used to rapidly perform quality control in industrial production of Tongkang tablets.


Asunto(s)
Comprimidos/química , Calibración , Cromatografía Líquida de Alta Presión/métodos , Cromonas/química , Cimicifuga/química , Glicósidos/química , Hesperidina/química , Isoflavonas/química , Análisis de los Mínimos Cuadrados , Control de Calidad , Espectroscopía Infrarroja Corta/métodos
8.
Zhonghua Nei Ke Za Zhi ; 53(12): 964-8, 2014 Dec.
Artículo en Zh | MEDLINE | ID: mdl-25623564

RESUMEN

OBJECTIVE: To compare the efficacy and safety of long-term treatment (48 weeks) with tiotropium bromide (5 µg) via Respimat(®) with placebo in patients with chronic obstructive pulmonary disease (COPD). METHODS: A total of 338 patients were randomized in this double-blind, placebo controlled, parallel study. All patients received either tiotropium bromide or placebo. Tiotropium bromide solution 5 µg (2×2.5 µg/puff) or matching placebo was delivered via Respimat(®) at a dosage of once daily for 48 weeks. Co-primary endpoints were trough forced expiratory volume in one second (FEV(1)) and the time to first exacerbation. RESULTS: Statistically significant improvements of both trough FEV(1) and trough forced vital capacity (FVC) in the tiotropium group were achieved at weeks 4, 24, and 48 compared with those in the placebo group (P < 0.000 1). Tiotropium treatment delayed the time to first exacerbation. The time was 157 days in the tiotropium group and 85 days in the placebo group. A statistically significant difference (P = 0.002 7) in favor of tiotropium was also observed. The total numbers of exacerbation during treatment were 90 and 128 in the tiotropium and placebo groups, respectively. The Poisson regression analysis gave a mean exacerbation rate per patient year exposure of 0.67 in the tiotropium group compared to 0.98 in the placebo group with a rate ratio of 0.69 (95%CI 0.50-0.93, P = 0.016 4). A much larger improvement from baseline in St. George's respiratory questionnaire (SGRQ) total score was observed for the tiotropium group than in the placebo group (P = 0.036 7), SGRQ symptom and activity scores of patients in the tiotropium group were also superior to those of patients receiving placebo. The drugs-related adverse events in the tiotropium and placebo groups were 12 cases and 11 cases, respectively. CONCLUSIONS: Tiotropium significantly improved lung function and quality of life, delayed the time to first exacerbation, reduced the number of exacerbation. Overall, tiotropium was well tolerated.


Asunto(s)
Broncodilatadores/administración & dosificación , Antagonistas Colinérgicos/administración & dosificación , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Derivados de Escopolamina/administración & dosificación , Administración por Inhalación , Broncodilatadores/efectos adversos , Antagonistas Colinérgicos/efectos adversos , Método Doble Ciego , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Calidad de Vida , Pruebas de Función Respiratoria , Seguridad , Derivados de Escopolamina/efectos adversos , Encuestas y Cuestionarios , Bromuro de Tiotropio , Resultado del Tratamiento
9.
PLoS One ; 19(4): e0300965, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38557554

RESUMEN

AIM: Our study aims to identify novel non-coding RNA-mRNA regulatory networks associated with ß-cell dysfunction and compensatory responses in obesity-related diabetes. METHODS: Glucose metabolism, islet architecture and secretion, and insulin sensitivity were characterized in C57BL/6J mice fed on a 60% high-fat diet (HFD) or control for 24 weeks. Islets were isolated for whole transcriptome sequencing to identify differentially expressed (DE) mRNAs, miRNAs, IncRNAs, and circRNAs. Regulatory networks involving miRNA-mRNA, lncRNA-mRNA, and lncRNA-miRNA-mRNA were constructed and functions were assessed through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. RESULTS: Despite compensatory hyperinsulinemia and a significant increase in ß-cell mass with a slow rate of proliferation, HFD mice exhibited impaired glucose tolerance. In isolated islets, insulin secretion in response to glucose and palmitic acid deteriorated after 24 weeks of HFD. Whole transcriptomic sequencing identified a total of 1324 DE mRNAs, 14 DE miRNAs, 179 DE lncRNAs, and 680 DE circRNAs. Our transcriptomic dataset unveiled several core regulatory axes involved in the impaired insulin secretion in HFD mice, such as miR-6948-5p/Cacna1c, miR-6964-3p/Cacna1b, miR-3572-5p/Hk2, miR-3572-5p/Cckar and miR-677-5p/Camk2d. Additionally, proliferative and apoptotic targets, including miR-216a-3p/FKBP5, miR-670-3p/Foxo3, miR-677-5p/RIPK1, miR-802-3p/Smad2 and ENSMUST00000176781/Caspase9 possibly contribute to the increased ß-cell mass in HFD islets. Furthermore, competing endogenous RNAs (ceRNA) regulatory network involving 7 DE miRNAs, 15 DE lncRNAs and 38 DE mRNAs might also participate in the development of HFD-induced diabetes. CONCLUSIONS: The comprehensive whole transcriptomic sequencing revealed novel non-coding RNA-mRNA regulatory networks associated with impaired insulin secretion and increased ß-cell mass in obesity-related diabetes.


Asunto(s)
Diabetes Mellitus , MicroARNs , ARN Largo no Codificante , Ratones , Animales , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Dieta Alta en Grasa/efectos adversos , ARN Circular/metabolismo , Secreción de Insulina , Secuenciación del Exoma , Ratones Endogámicos C57BL , MicroARNs/genética , MicroARNs/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Obesidad/genética , Redes Reguladoras de Genes , Canales de Calcio Tipo N/metabolismo
10.
iScience ; 27(5): 109665, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38646167

RESUMEN

Glucagon is secreted by pancreatic α-cells to counteract hypoglycaemia. How glucose regulates glucagon secretion remains unclear. Here, using mouse islets, we studied the role of transmembrane and endoplasmic reticulum (ER) Ca2+ on intrinsic α-cell glucagon secretion. Blocking isradipine-sensitive L-type voltage-gated Ca2+ (Cav) channels abolished α-cell electrical activity but had little impact on its cytosolic Ca2+ oscillations or low-glucose-stimulated glucagon secretion. In contrast, depleting ER Ca2+ with cyclopiazonic acid or blocking ER Ca2+-releasing ryanodine receptors abolished α-cell glucose sensitivity and low-glucose-stimulated glucagon secretion. ER Ca2+ mobilization in α-cells is regulated by intracellular ATP and likely to be coupled to Ca2+ influx through P/Q-type Cav channels. ω-Agatoxin IVA blocked α-cell ER Ca2+ release and cell exocytosis, but had no additive effect on glucagon secretion when combined with ryanodine. We conclude that glucose regulates glucagon secretion through the control of ER Ca2+ mobilization, a mechanism that can be independent of α-cell electrical activity.

11.
Plant Physiol ; 158(2): 693-707, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22170977

RESUMEN

The chloroplast ribosome is a large and dynamic ribonucleoprotein machine that is composed of the 30S and 50S subunits. Although the components of the chloroplast ribosome have been identified in the last decade, the molecular mechanisms driving chloroplast ribosome biogenesis remain largely elusive. Here, we show that RNA helicase 22 (RH22), a putative DEAD RNA helicase, is involved in chloroplast ribosome assembly in Arabidopsis (Arabidopsis thaliana). A loss of RH22 was lethal, whereas a knockdown of RH22 expression resulted in virescent seedlings with clear defects in chloroplast ribosomal RNA (rRNA) accumulation. The precursors of 23S and 4.5S, but not 16S, rRNA accumulated in rh22 mutants. Further analysis showed that RH22 was associated with the precursors of 50S ribosomal subunits. These results suggest that RH22 may function in the assembly of 50S ribosomal subunits in chloroplasts. In addition, RH22 interacted with the 50S ribosomal protein RPL24 through yeast two-hybrid and pull-down assays, and it was also bound to a small 23S rRNA fragment encompassing RPL24-binding sites. This action of RH22 may be similar to, but distinct from, that of SrmB, a DEAD RNA helicase that is involved in the ribosomal assembly in Escherichia coli, which suggests that DEAD RNA helicases and rRNA structures may have coevolved with respect to ribosomal assembly and function.


Asunto(s)
Arabidopsis/metabolismo , ARN Helicasas DEAD-box/metabolismo , Subunidades Ribosómicas/metabolismo , Arabidopsis/enzimología , Cloroplastos/metabolismo , ARN Helicasas DEAD-box/genética , Técnicas de Silenciamiento del Gen , ARN Mensajero/genética
12.
Plant Physiol ; 160(4): 1911-22, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23043079

RESUMEN

The biogenesis and assembly of photosynthetic multisubunit protein complexes is assisted by a series of nucleus-encoded auxiliary protein factors. In this study, we characterize the dac mutant of Arabidopsis (Arabidopsis thaliana), which shows a severe defect in the accumulation of the cytochrome b(6)/f complex, and provide evidence suggesting that the efficiency of cytochrome b(6)/f complex assembly is affected in the mutant. DAC is a thylakoid membrane protein with two predicted transmembrane domains that is conserved from cyanobacteria to vascular plants. Yeast (Saccharomyces cerevisiae) two-hybrid and coimmunoprecipitation analyses revealed a specific interaction between DAC and PetD, a subunit of the cytochrome b(6)/f complex. However, DAC was found not to be an intrinsic component of the cytochrome b(6)/f complex. In vivo chloroplast protein labeling experiments showed that the labeling rates of the PetD and cytochrome f proteins were greatly reduced, whereas that of the cytochrome b(6) protein remained normal in the dac mutant. DAC appears to be a novel factor involved in the assembly/stabilization of the cytochrome b(6)/f complex, possibly through interaction with the PetD protein.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Complejo de Citocromo b6f/metabolismo , Proteínas de las Membranas de los Tilacoides/metabolismo , Secuencia de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Datos de Secuencia Molecular , Mutación/genética , Fenotipo , Polirribosomas/metabolismo , Unión Proteica , Estabilidad Proteica , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de Secuencia , Espectrometría de Fluorescencia , Fracciones Subcelulares/metabolismo , Sacarosa/metabolismo , Proteínas de las Membranas de los Tilacoides/química , Proteínas de las Membranas de los Tilacoides/genética , Tilacoides/metabolismo
13.
J Endocrinol ; 258(2)2023 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-37159865

RESUMEN

Glucagon is the principal glucose-elevating hormone that forms the first-line defence against hypoglycaemia. Along with insulin, glucagon also plays a key role in maintaining systemic glucose homeostasis. The cells that secrete glucagon, pancreatic α-cells, are electrically excitable cells and use electrical activity to couple its hormone secretion to changes in ambient glucose levels. Exactly how glucose regulates α-cells has been a topic of debate for decades but it is clear that electrical signals generated by the cells play an important role in glucagon secretory response. Decades of studies have already revealed the key players involved in the generation of these electrical signals and possible mechanisms controlling them to tune glucagon release. This has offered the opportunity to fully understand the enigmatic α-cell physiology. In this review, we describe the current knowledge on cellular electrophysiology and factors regulating excitability, glucose sensing, and glucagon secretion. We also discuss α-cell pathophysiology and the perspective of addressing glucagon secretory defects in diabetes for developing better diabetes treatment, which bears the hope of eliminating hypoglycaemia as a clinical problem in diabetes care.


Asunto(s)
Diabetes Mellitus , Células Secretoras de Glucagón , Hipoglucemia , Humanos , Glucagón , Insulina , Glucosa , Fenómenos Fisiológicos Celulares , Electrofisiología
14.
Front Endocrinol (Lausanne) ; 14: 1234918, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37900151

RESUMEN

Aim: To probe the appropriate iodine nutritional status for patients with Graves'disease (GD) hyperthyroidism and on antithyroid drugs (ATD) or after drugwithdrawal. Method: Studies were retrieved from three databases (Embase, Medline, and Cochrane Library) and were screened and evaluated using predefined criteria. The risk of bias of each trial was assessed using a tool from Cochrane. The iodine nutritional status of the subjects was redefined according to the World Health Organization (WHO) criteria and classified as insufficient/adequate/above requirements/excessive iodine intake. Result: Two randomized controlled trials (RCTs) and 3 observational studies were selected from the 376 retrieved papers, which had different degrees of risk of bias in study design. The heterogeneity among them prevented us from further synthesizing effect indicators and subsequent statistical analyses. Two RCTs with high quality showed that insufficient or above requirements iodine intake was detrimental for ATD-treated GD patients; adequate iodine intake was associated with a lower risk of recurrence and better efficacy in controlling thyrotoxicosis. It could be speculated from three low-quality observational studies that excessive iodine intake may be associated with higher (or similar) recurrence rates and lower remission rates compared to above requirements iodine intake in these patients, but none of them could answer the question of the effect of insufficient or adequate iodine intake on this issue. Conclusion: Although the available evidence is suboptimal, this systematic review tentatively suggests that in adult patients with GD hyperthyroidism receiving ATDs and according to WHO criteria for iodine nutritional status, adequate iodine intake is associated with a lower recurrence rate, a higher remission rate and a better efficacy to control thyrotoxicosis than insufficient, above requirement, or excessive iodine intake. Future RCTs with large samples are expected to elucidate the actual impact of different iodine nutritional statuses on the recurrence rate of hyperthyroidism and the efficacy of ATD to control thyrotoxicosis in these patients. Systematic review registration: identifier CRD42022359451.


Asunto(s)
Enfermedad de Graves , Hipertiroidismo , Yodo , Tirotoxicosis , Humanos , Adulto , Antitiroideos/uso terapéutico , Yodo/uso terapéutico , Estado Nutricional , Enfermedad de Graves/tratamiento farmacológico , Hipertiroidismo/tratamiento farmacológico , Hipertiroidismo/epidemiología , Hipertiroidismo/inducido químicamente
15.
Biofactors ; 49(3): 646-662, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36714992

RESUMEN

The semi-essential ubiquitous amino acid taurine has been shown to alleviate obesity and hyperglycemia in humans; however, the pathways underlying the antidiabetic actions have not been characterized. We explored the effect of chronic taurine exposure on cell biology of pancreatic islets, in degenerative type 1-like diabetes. The latter was modeled by small dose of streptozotocin (STZ) injection for 5 days in mice, followed by a 10-day administration of taurine (2% w/v, orally) in the drinking water. Taurine treatment opposed the detrimental changes in islet morphology and ß-/α-cell ratio, induced by STZ diabetes, coincidentally with a significant 3.9 ± 0.7-fold enhancement of proliferation and 40 ± 5% reduction of apoptosis in ß-cells. In line with these findings, the treatment counteracted an upregulation of antioxidant (Sod1, Sod2, Cat, Gpx1) and downregulation of islet expansion (Ngn3, Itgb1) genes induced by STZ, in a pancreatic ß-cell line. At the same time, taurine enhanced the transdifferentiation of α-cells into ß-cells by 2.3 ± 0.8-fold, echoed in strong non-metabolic elevation of cytosolic Ca2+ levels in pancreatic α-cells. Our data suggest a bimodal effect of dietary taurine on islet ß-cell biology, which combines the augmentation of α-/ß-cell transdifferentiation with downregulation of apoptosis. The dualism of action, stemming presumably from the intra- and extracellular modality of the signal, is likely to explain the antidiabetic potential of taurine supplementation.


Asunto(s)
Células Secretoras de Insulina , Islotes Pancreáticos , Humanos , Ratones , Animales , Taurina/farmacología , Transdiferenciación Celular , Glucemia/metabolismo , Islotes Pancreáticos/metabolismo , Hipoglucemiantes/farmacología , Estreptozocina , Insulina/metabolismo
16.
J Biophotonics ; 16(3): e202200251, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36177762

RESUMEN

Hepatitis B is an infectious disease cause by the hepatitis B virus (HBV). In recent years, HBV-DNA level clinically gets more attention for its detailed information than other serological markers. Unfortunately, common clinical method for HBV-DNA level detection is limited for its hours consuming. This study combined infrared spectroscopy with machine learning to investigate the feasibility of near-infrared (NIR) and mid-infrared (MIR) spectra for rapid detection of HBV-DNA level. Based on partial least squares-discriminant analysis (PLS-DA) modeling method, the optimal NIR and MIR models and traditional data fusion models were constructed, respectively. Considering inequal weight between interval and point data in machine learning, interval-point data fusion method was used to compare with other traditional date fusion methods. The results of the study illustrate that interval-point data fusion of NIR and MIR spectra combined with PLS-DA modeling can provide a rapid method for HBV-DNA level detection.


Asunto(s)
Virus de la Hepatitis B , Espectroscopía Infrarroja Corta , Espectroscopía Infrarroja Corta/métodos , ADN Viral , Espectrofotometría Infrarroja , Análisis Discriminante , Análisis de los Mínimos Cuadrados
17.
Front Microbiol ; 14: 1107649, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36778865

RESUMEN

The feasibility of sulfur enhancement for uranium bioleaching in column reactors was assessed with a designed mixed Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferriphilum from a refractory uranium ore. The uranium extraction reached 86.2% with the sulfur enhancement (1 g/kg) in 77 days leaching process, increased by 12.6% vs. the control without sulfur addition. The kinetic analysis showed that uranium bioleaching with sulfur enhancement in columns followed an internal diffusion through the product layer-controlled model. Ore residue characteristics indicated that sulfur enhancement could strengthen the porosity of passivation layer, improving the ore permeability. Notably, bacterial community analysis showed that sulfur enhancement at 1 g/kg could make the iron-oxidizing and sulfur-oxidizing bacteria on the ore surface maintain a good balance (approx. 1:1), and thus decomposing ore more effectively. Lastly, a possible mechanism model for uranium bioleaching with sulfur enhancement was proposed.

18.
Cell Signal ; 102: 110535, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36436799

RESUMEN

Endoplasmic reticulum (ER) stress is closely associated with type 2 diabetes (T2D). Activating transcription factor 5 (ATF5) is a member of the ATF/cAMP response element binding protein (CREB) family whose levels are increased upon stress in pancreatic islets from mice. Intriguingly, ATF5 deficiency has been shown to contribute to increased ER stress and apoptosis in mouse islet micro-organs. We hypothesized that either deficiency or overexpression of ATF5 is equally deleterious for pancreatic islets in terms of ER stress and apoptosis. To test this, we used a number of in vitro and in vivo models whereby ATF5 levels were overexpressed. We also determined the regulation of ATF5 in the context of metabolic derangements by using various mouse models of obesity and T2D. Our in vitro results show that ATF5 overexpression promoted palmitic acid (PA)-induced lipotoxic apoptosis. In vivo, global ATF5 overexpression in mice was lethal and pancreas-specific ATF5 overexpressing mice exhibit increased ß-cell apoptosis. Interestingly, ATF5 is downregulated in all mouse models of severe obesity and T2D used in the current study. In conclusion, a tight control on ATF5 levels might be considered when developing novel agents targeting ATF5 for prevention and treatment of metabolic diseases.


Asunto(s)
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Ratones , Animales , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Factores de Transcripción Activadores/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Apoptosis/fisiología , Modelos Animales de Enfermedad , Dieta , Obesidad/metabolismo , Células Secretoras de Insulina/metabolismo , Estrés del Retículo Endoplásmico/fisiología
19.
Foods ; 12(22)2023 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-38002117

RESUMEN

Gastrodia elata (G. elata) Blume is widely used as a health product with significant economic, medicinal, and ecological values. Due to variations in the geographical origin, soil pH, and content of organic matter, the levels of physiologically active ingredient contents in G. elata from different origins may vary. Therefore, rapid methods for predicting the geographical origin and the contents of these ingredients are important for the market. This paper proposes a visible-near-infrared (Vis-NIR) spectroscopy technology combined with machine learning. A variety of machine learning models were benchmarked against a one-dimensional convolutional neural network (1D-CNN) in terms of accuracy. In the origin identification models, the 1D-CNN demonstrated excellent performance, with the F1 score being 1.0000, correctly identifying the 11 origins. In the quantitative models, the 1D-CNN outperformed the other three algorithms. For the prediction set of eight physiologically active ingredients, namely, GA, HA, PE, PB, PC, PA, GA + HA, and total, the RMSEP values were 0.2881, 0.0871, 0.3387, 0.2485, 0.0761, 0.7027, 0.3664, and 1.2965, respectively. The Rp2 values were 0.9278, 0.9321, 0.9433, 0.9094, 0.9454, 0.9282, 0.9173, and 0.9323, respectively. This study demonstrated that the 1D-CNN showed highly accurate non-linear descriptive capability. The proposed combinations of Vis-NIR spectroscopy with 1D-CNN models have significant potential in the quality evaluation of G. elata.

20.
J Carcinog ; 11: 8, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22919281

RESUMEN

BACKGROUND: Sulforaphane (SFN), an activator of nuclear factor erythroid-2 related factor 2 (Nrf2), is a promising chemopreventive agent which is undergoing clinical trial for several diseases. Studies have indicated that there is gain of Nrf2 function in lung cancer and other solid tumors because of mutations in the inhibitor Kelch-like ECH-associated protein 1 (Keap1). More recently, several oncogenes have been shown to activate Nrf2 signaling as the main prosurvival pathway mediating ROS detoxification, senescence evasion, and neoplastic transformation. Thus, it is important to determine if there is any risk of enhanced lung tumorigenesis associated with prolonged administration of SFN using mouse models of cancer. MATERIALS AND METHODS: We evaluated the effect of prolonged SFN treatment on oncogenic K-ras (K-ras(LSL-G12D))-driven lung tumorigenesis. One week post mutant-K-ras expression, mice were treated with SFN (0.5 mg, 5 d/wk) for 3 months by means of a nebulizer. Fourteen weeks after mutant K-ras expression (K-ras(LSL-G12D)), mice were sacrificed, and lung sections were screened for neoplastic foci. Expression of Nrf2-dependent genes was measured using real time RT-PCR. We also determined the effect of prolonged SFN treatment on the growth of preclinical xenograft models using human A549 (with mutant K-ras and Keap1 allele) and H1975 [with mutant epidermal growth factor receptor (EGFR) allele] nonsmall cell lung cancer cells. RESULTS: Systemic SFN administration did not promote the growth of K-ras(LSL-G12D)-induced lung tumors and had no significant effect on the growth of A549 and H1975 established tumor xenografts in nude mice. Interestingly, localized delivery of SFN significantly attenuated the growth of A549 tumors in nude mice, suggesting an Nrf2-independent antitumorigenic activity of SFN. CONCLUSIONS: Our results demonstrate that prolonged SFN treatment does not promote lung tumorigenesis in various mouse models of lung cancer.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA