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BACKGROUND: γ-aminobutyric acid (GABA), known as the main inhibitory neurotransmitter in the brain, exerts immunomodulatory functions by interaction with immune cells, including T cells. Metabolic programs of T cells are closely linked to their effector functions including proliferation, differentiation, and cytokine production. The physiological molecules glucose and insulin may provide environmental cues and guidance, but whether they coordinate to regulate GABA-mediated T cell immunomodulation is still being examined. METHODS: CD4+ T cells that were isolated from blood samples from healthy individuals and from patients with type 1 diabetes (T1D) were activated in vitro. We carried out metabolic assays, multiple proximity extension assay (PEA), ELISA, qPCR, immunoblotting, immunofluorescence staining, flow cytometry analysis, MS-based proteomics, as well as electrophysiology and live-cell Ca2+ imaging. FINDINGS: We demonstrate that GABA-mediated reduction of metabolic activity and the release of inflammatory proteins, including IFNγ and IL-10, were abolished in human CD4+ T cells from healthy individuals and patients with T1D when the glucose concentration was elevated above levels typically observed in healthy people. Insulin increased GABAA receptor-subunit ρ2 expression, enhanced the GABAA receptors-mediated currents and Ca2+ influx. GABA decreased, whereas insulin sustained, hexokinase activity and glycolysis in a glucose concentration-dependent manner. INTERPRETATION: These findings support that metabolic factors, such as glucose and insulin, influence the GABA-mediated immunomodulation of human primary T cells effector functions. FUNDING: The Swedish Children's Diabetes Foundation, The Swedish Diabetes Foundation, The Swedish Research Council 2018-02952, EXODIAB, The Ernfors Foundation, The Thurings Foundation and the Science for Life Laboratory.
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Linfocitos T CD4-Positivos , Diabetes Mellitus Tipo 1 , Glucosa , Insulina , Ácido gamma-Aminobutírico , Humanos , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/inmunología , Ácido gamma-Aminobutírico/metabolismo , Insulina/metabolismo , Glucosa/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/inmunología , Masculino , Femenino , Citocinas/metabolismo , Adulto , Receptores de GABA-A/metabolismo , Activación de LinfocitosRESUMEN
In the North Sea, Tripos and Dinophysis are commonly occurring mixotrophic planktonic dinoflagellate genera. In order to understand their bloom dynamics, an occurring bloom dominated by T. furca and D. norvegica was followed for several days. High cell abundances of these species were located to estimate: in situ growth rates from cell cycle analyses, depth distributions, growth rates sustained by photosynthesis, and parasite infection prevalence in all T. furca, T. fusus, D. norvegica and D. acuminata. Cell abundances were over 10000 cells L-1 for T. furca and up to 18000 cells L-1 for D. norvegica. Cells accumulated between 15-25 m depth and presented low specific in situ growth rates of 0.04-0.15 d-1 for T. furca and 0.02-0.16 d-1 for D. norvegica. Photosynthesis could sustain growth rates of 0.01-0.18 d-1 for T. furca and 0.02 to 0.14 d-1 for D. norvegica, suggesting that these species were relying mainly on photosynthesis. Parasite infections where generally low, with occasional high prevalence in D. norvegica (by Parvilucifera sp.) and T. fusus (by Amoebophrya sp.), while both parasites showed comparable prevalence in D. acuminata, which could offset in situ growth rates by parasite-induced host mortality. The restructuring effect of parasites on dinoflagellate blooms is often overlooked and this study elucidates their effect to cell abundances and their growth at the final stages of a bloom.
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Dinoflagelados , Fotosíntesis , Dinámica Poblacional , Dinoflagelados/fisiología , Dinoflagelados/crecimiento & desarrollo , Mar del Norte , Floraciones de Algas NocivasRESUMEN
Pluripotent stem cell-derived islets (SC-islets) have emerged as a new source for ß-cell replacement therapy. The function of human islet transplants is hampered by excessive cell death posttransplantation; contributing factors include inflammatory reactions, insufficient revascularization, and islet amyloid formation. However, there is a gap in knowledge of the engraftment process of SC-islets. In this experimental study, we investigated the engraftment capability of SC-islets at 3 months posttransplantation and observed that cell apoptosis rates were lower but vascular density was similar in SC-islets compared with human islets. Whereas the human islet transplant vascular structures were a mixture of remnant donor endothelium and ingrowing blood vessels, the SC-islets contained ingrowing blood vessels only. Oxygenation in the SC-islet grafts was twice as high as that in the corresponding grafts of human islets, suggesting better vascular functionality. Similar to the blood vessel ingrowth, reinnervation of the SC-islets was four- to fivefold higher than that of the human islets. Both SC-islets and human islets contained amyloid at 1 and 3 months posttransplantation. We conclude that the vascular and neural engraftment of SC-islets are superior to those of human islets, but grafts of both origins develop amyloid, with potential long-term consequences.
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Trasplante de Islotes Pancreáticos , Islotes Pancreáticos , Humanos , Trasplante de Islotes Pancreáticos/métodos , Islotes Pancreáticos/irrigación sanguínea , Islotes Pancreáticos/citología , Islotes Pancreáticos/fisiología , Animales , Ratones , Apoptosis/fisiología , Células Madre Pluripotentes/citología , Células Madre Pluripotentes/fisiología , Supervivencia de Injerto/fisiología , MasculinoRESUMEN
INTRODUCTION: The rate of progression to complete insulin deficiency varies greatly in type 1 diabetes. This constitutes a challenge, especially when randomizing patients in intervention trials aiming to preserve beta cell function. This study aimed to identify biomarkers predictive of either a rapid or slow disease progression in children with new-onset type 1 diabetes. RESEARCH DESIGN AND METHODS: A retrospective, longitudinal cohort study of children (<18 years) with type 1 diabetes (N=46) was included at diagnosis and followed until complete insulinopenia (C-peptide <0.03 nmol/L). Children were grouped into rapid progressors (n=20, loss within 30 months) and slow progressors (n=26). A sex-matched control group of healthy children (N=45) of similar age was included for comparison. Multiple biomarkers were assessed by proximity extension assay (PEA) at baseline and follow-up. RESULTS: At baseline, rapid progressors had lower C-peptide and higher autoantibody levels than slow. Three biomarkers were higher in the rapid group: carbonic anhydrase 9, corticosteroid 11-beta-dehydrogenase isozyme 1, and tumor necrosis factor receptor superfamily member 21. In a linear mixed model, 25 proteins changed over time, irrespective of group. One protein, a coxsackievirus B-adenovirus receptor (CAR) increased over time in rapid progressors. Eighty-one proteins differed between type 1 diabetes and healthy controls. Principal component analysis could not distinguish between rapid, slow, and healthy controls. CONCLUSIONS: Despite differences in individual proteins, the combination of multiple biomarkers analyzed by PEA could not distinguish the rate of progression in children with new-onset type 1 diabetes. Only one marker was altered significantly when considering both time and group effects, namely CAR, which increased significantly over time in the rapid group. Nevertheless, we did find some markers that may be useful in predicting the decline of the C-peptide. Moreover, these could potentially be important for understanding type 1 diabetes pathogenesis.
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Diabetes Mellitus Tipo 1 , Niño , Humanos , Diabetes Mellitus Tipo 1/patología , Insulina/metabolismo , Estudios Longitudinales , Estudios Retrospectivos , Péptido C , Autoanticuerpos , Insulina Regular Humana , BiomarcadoresRESUMEN
2,4-dimethylfuran has a rare disubstitution pattern in the five-membered heterocyclic furan ring that is highly interesting chemically but challenging to access synthetically. We present a heterogeneously catalysed route to synthesise 2,4-dimethylfuran from commonly available 2,5-dimethylfuran using a zeolite packed-bed flow reactor. As supported by DFT calculations, the reaction occurs inside the zeolite channels, where the acid sites catalyse proton transfer followed by migration of a methyl group. The zeotype Ga-silicate (MFI type) appears superior to an aluminium-containing ZSM-5 by demonstrating higher selectivities and slower catalyst deactivation. This work provides new opportunities for the continuous valorisation of bio-feedstock molecules in the perspective of the emerging biorefinery era.
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BACKGROUND: Both tinnitus and hearing loss are multidimensional. The purpose of this study was to identify and determine the degree of mental fatigue in patients with hearing loss and/or tinnitus participating in audiological rehabilitation, and to examine the self-reported mental fatigue scale (MFS) in this patient group. METHODS: Patients undergoing audiological rehabilitation at the Department of Audiology and Neurotology, Karolinska University Hospital, Sweden, between 2011 and 2017 who completed a self-reported MFS questionnaire were investigated. Data on 76 patients were analysed in this pilot study. Patients were also assessed using the Tinnitus Handicap Inventory (THI). RESULTS: The study population had an age range of 38-65 years, and most had normal hearing (37%) or mild to moderate hearing loss (46%). Only 17% had severe to profound hearing loss. A total of 56.5% had tinnitus, of whom 39.5% scored ≥57 on the THI, indicating severe tinnitus, whereas 43.5% reported no tinnitus. The MFS scores, ranging from 13 to 42.5 points, were divided into three severity levels for analysis: 10.5-15, 15.5-20, and ≥20.5. In total, 67% of the patients had MFS scores ≥ 20.5. Importantly, most of the participants (90%) with a THI score ≥ 57 belonged to that group. A significant positive correlation between a high MFS score and severe tinnitus was found. CONCLUSIONS: The study reveals that severe mental fatigue is more common in patients with severe tinnitus than sole hearing loss.
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NADPH oxidase 4 (NOX4) inhibition has been reported to mitigate diabetes-induced beta-cell dysfunction and improve survival in vitro, as well as counteract high-fat diet-induced glucose intolerance in mice. We investigated the antidiabetic effects of the selective NOX4 inhibitor GLX7013159 in vivo in athymic diabetic mice transplanted with human islets over a period of 4 weeks. The GLX7013159-treated mice achieved lower blood glucose and water consumption throughout the treatment period. Furthermore, GLX7013159 treatment resulted in improved insulin and c-peptide levels, better insulin secretion capacity, as well as in greatly reduced apoptotic rates of the insulin-positive human cells, measured as colocalization of insulin and cleaved caspase-3. We conclude that the antidiabetic effects of NOX4 inhibition by GLX7013159 are observed also during a prolonged study period in vivo and are likely to be due to an improved survival and function of the human beta-cells.
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Diabetes Mellitus Experimental , Insulinas , Humanos , Ratones , Animales , NADPH Oxidasa 4 , Glucemia , Hipoglucemiantes , Insulina , Glucosa/farmacologíaRESUMEN
Intensive treatments for posttraumatic stress disorder (PTSD) are gaining increased research support. Treatment models targeting Complex PTSD and previously treatment-resistant PTSD have shown a good effect. A pilot study was performed to assess the feasibility of an 8-day intensive treatment program for severe PTSD in a Swedish public healthcare setting. Eleven participants completed treatment, and overall, the reduction in PTSD symptoms was considerable. Also, loss of diagnosis at 3-month follow-up was 100%. No adverse events occurred, and no elevation of suicidal intentions was reported. Symptom exacerbation could not be observed in the data and dropout due to the intensity of the treatment format did not occur. Based on these positive results, it is recommended that further research with larger samples is conducted. If found safe and effective, the 8-day treatment program could be an important addition to psychiatric healthcare.
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AIM/HYPOTHESIS: This study aimed to investigate the safety and efficacy of treatment with allogeneic Wharton's jelly-derived mesenchymal stromal cells (MSCs) in recent-onset type 1 diabetes. METHODS: A combined Phase I/II trial, composed of a dose escalation followed by a randomised double-blind placebo-controlled study in parallel design, was performed in which treatment with allogeneic MSCs produced as an advanced therapy medicinal product (ProTrans) was compared with placebo in adults with newly diagnosed type 1 diabetes. Inclusion criteria were a diagnosis of type 1 diabetes <2 years before enrolment, age 18-40 years and a fasting plasma C-peptide concentration >0.12 nmol/l. Randomisation was performed with a web-based randomisation system, with a randomisation code created prior to the start of the study. The randomisation was made in blocks, with participants randomised to ProTrans or placebo treatment. Randomisation envelopes were kept at the clinic in a locked room, with study staff opening the envelopes at the baseline visits. All participants and study personnel were blinded to group assignment. The study was conducted at Karolinska University Hospital, Stockholm, Sweden. RESULTS: Three participants were included in each dose cohort during the first part of the study. Fifteen participants were randomised in the second part of the study, with ten participants assigned to ProTrans treatment and five to placebo. All participants were analysed for the primary and secondary outcomes. No serious adverse events related to treatment were observed and, overall, few adverse events (mainly mild upper respiratory tract infections) were reported in the active treatment and placebo arms. The primary efficacy endpoint was defined as Δ-change in C-peptide AUC for a mixed meal tolerance test at 1 year following ProTrans/placebo infusion compared with baseline performance prior to treatment. C-peptide levels in placebo-treated individuals declined by 47%, whereas those in ProTrans-treated individuals declined by only 10% (p<0.05). Similarly, insulin requirements increased in placebo-treated individuals by a median of 10 U/day, whereas insulin needs of ProTrans-treated individuals did not change over the follow-up period of 12 months (p<0.05). CONCLUSIONS/INTERPRETATION: This study suggests that allogeneic Wharton's jelly-derived MSCs (ProTrans) is a safe treatment for recent-onset type 1 diabetes, with the potential to preserve beta cell function. TRIAL REGISTRATION: ClinicalTrials.gov NCT03406585 FUNDING: The sponsor of the clinical trial is NextCell Pharma AB, Stockholm, Sweden.
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COVID-19 , Diabetes Mellitus Tipo 1 , Células Madre Mesenquimatosas , Adulto , Humanos , Adolescente , Adulto Joven , Diabetes Mellitus Tipo 1/tratamiento farmacológico , SARS-CoV-2 , Insulina/uso terapéutico , Péptido C , Resultado del Tratamiento , Método Doble Ciego , Cordón UmbilicalRESUMEN
INTRODUCTION: To improve the utilization of continuous- and flash glucose monitoring (CGM/FGM) data we have tested the hypothesis that a machine learning (ML) model can be trained to identify the most likely root causes for hypoglycemic events. METHODS: CGM/FGM data were collected from 449 patients with type 1 diabetes. Of the 42,120 identified hypoglycemic events, 5041 were randomly selected for classification by two clinicians. Three causes of hypoglycemia were deemed possible to interpret and later validate by insulin and carbohydrate recordings: (1) overestimated bolus (27%), (2) overcorrection of hyperglycemia (29%) and (3) excessive basal insulin presure (44%). The dataset was split into a training (n = 4026 events, 304 patients) and an internal validation dataset (n = 1015 events, 145 patients). A number of ML model architectures were applied and evaluated. A separate dataset was generated from 22 patients (13 'known' and 9 'unknown') with insulin and carbohydrate recordings. Hypoglycemic events from this dataset were also interpreted by five clinicians independently. RESULTS: Of the evaluated ML models, a purpose-built convolutional neural network (HypoCNN) performed best. Masking the time series, adding time features and using class weights improved the performance of this model, resulting in an average area under the curve (AUC) of 0.921 in the original train/test split. In the dataset validated by insulin and carbohydrate recordings (n = 435 events), i.e. 'ground truth,' our HypoCNN model achieved an AUC of 0.917. CONCLUSIONS: The findings support the notion that ML models can be trained to interpret CGM/FGM data. Our HypoCNN model provides a robust and accurate method to identify root causes of hypoglycemic events.
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[This corrects the article DOI: 10.1371/journal.pone.0161834.].
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MODY3 is a monogenic hereditary form of diabetes caused by mutations in the transcription factor HNF1A. The patients progressively develop hyperglycemia due to perturbed insulin secretion, but the pathogenesis is unknown. Using patient-specific hiPSCs, we recapitulate the insulin secretion sensitivity to the membrane depolarizing agent sulfonylurea commonly observed in MODY3 patients. Unexpectedly, MODY3 patient-specific HNF1A+/R272C ß cells hypersecrete insulin both in vitro and in vivo after transplantation into mice. Consistently, we identified a trend of increased birth weight in human HNF1A mutation carriers compared with healthy siblings. Reduced expression of potassium channels, specifically the KATP channel, in MODY3 ß cells, increased calcium signaling, and rescue of the insulin hypersecretion phenotype by pharmacological targeting ATP-sensitive potassium channels or low-voltage-activated calcium channels suggest that more efficient membrane depolarization underlies the hypersecretion of insulin in MODY3 ß cells. Our findings identify a pathogenic mechanism leading to ß cell failure in MODY3.
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Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Humanos , Ratones , Animales , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Diabetes Mellitus Tipo 2/genética , FenotipoRESUMEN
INTRODUCTION: Pregnancy entails both pancreatic adaptations with increasing ß-cell mass and immunological alterations in healthy women. In this study, we have examined the effects of pregnancy on ß-cell function and immunological processes in long-standing type 1 diabetes (L-T1D). RESEARCH DESIGN AND METHODS: Fasting and stimulated C-peptide were measured after an oral glucose tolerance test in pregnant women with L-T1D (n=17) during the first trimester, third trimester, and 5-8 weeks post partum. Two 92-plex Olink panels were used to measure proteins in plasma. Non-pregnant women with L-T1D (n=30) were included for comparison. RESULTS: Fasting C-peptide was detected to a higher degree in women with L-T1D during gestation and after parturition (first trimester: 64.7%, third trimester: 76.5%, and post partum: 64.7% vs 26.7% in non-pregnant women). Also, total insulin secretion and peak C-peptide increased during pregnancy. The plasma protein levels in pregnant women with L-T1D was dynamic, but few analytes were functionally related. Specifically, peripheral levels of prolactin (PRL), prokineticin (PROK)-1, and glucagon (GCG) were elevated during gestation whereas levels of proteins related to leukocyte migration (CCL11), T cell activation (CD28), and antigen presentation (such as CD83) were reduced. CONCLUSIONS: In summary, we have found that some C-peptide secretion, that is, an indirect measurement of endogenous insulin production, is regained in women with L-T1D during pregnancy, which might be attributed to elevated peripheral levels of PRL, PROK-1, or GCG.
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Diabetes Mellitus Tipo 1 , Insulina , Embarazo , Femenino , Humanos , Insulina/metabolismo , Secreción de Insulina , Péptido C , Prueba de Tolerancia a la Glucosa , Insulina Regular Humana/metabolismoRESUMEN
INTRODUCTION: The progression to insulin deficiency in type 1 diabetes is heterogenous. This study aimed to identify early characteristics associated with rapid or slow decline of beta-cell function and how it affects the clinical course. RESEARCH DESIGN AND METHODS: Stimulated C-peptide was assessed by mixed meal tolerance test in 50 children (<18 years) during 2004-2017, at regular intervals for 6 years from type 1 diabetes diagnosis. 40% of the children had a rapid decline of stimulated C-peptide defined as no measurable C-peptide (<0.03 nmol/L) 30 months after diagnosis. RESULTS: At diagnosis, higher frequencies of detectable glutamic acid decarboxylase antibodies (GADA) and IA-2A (p=0.027) were associated with rapid loss of beta-cell function. C-peptide was predicted positively by age at 18 months (p=0.017) and 30 months duration (p=0.038). BMI SD scores (BMISDS) at diagnosis predicted higher C-peptide at diagnosis (p=0.006), 3 months (p=0.002), 9 months (p=0.005), 30 months (p=0.022), 3 years (p=0.009), 4 years (p=0.016) and 6 years (p=0.026), whereas high HbA1c and blood glucose at diagnosis predicted a lower C-peptide at diagnosis (p=<0.001) for both comparisons. Both GADA and IA-2A were negative predictors of C-peptide at 9 months (p=0.011), 18 months (p=0.008) and 30 months (p<0.001). Ten children had 22 events of severe hypoglycemia, and they had lower mean C-peptide at 18 months (p=0.025), 30 months (p=0.008) and 6 years (p=0.018) compared with others. Seven of them had a rapid decline of C-peptide (p=0.030), and the odds to experience a severe hypoglycemia were nearly fivefold increased (OR=4.846, p=0.04). CONCLUSIONS: Low age and presence of multiple autoantibodies at diagnosis predicts a rapid loss of beta-cell function in children with type 1 diabetes. Low C-peptide is associated with an increased risk of severe hypoglycemia and higher Hemoglobin A1C. A high BMISDS at diagnosis is predictive of remaining beta-cell function during the 6 years of follow-up.
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Diabetes Mellitus Tipo 1 , Hipoglucemia , Niño , Adolescente , Humanos , Lactante , Péptido C , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/diagnóstico , Autoanticuerpos , Hipoglucemia/diagnóstico , InsulinaRESUMEN
A two-step seeded-growth method was refined to synthesize Au@Pd core@shell nanoparticles with thin Pd shells, which were then deposited onto alumina to obtain a supported Au@Pd/Al2O3 catalyst active for prototypical CO oxidation. By the strict control of temperature and Pd/Au molar ratio and the use of l-ascorbic acid for making both Au cores and Pd shells, a 1.5 nm Pd layer is formed around the Au core, as evidenced by transmission electron microscopy and energy-dispersive spectroscopy. The core@shell structure and the Pd shell remain intact upon deposition onto alumina and after being used for CO oxidation, as revealed by additional X-ray diffraction and X-ray photoemission spectroscopy before and after the reaction. The Pd shell surface was characterized with in situ infrared (IR) spectroscopy using CO as a chemical probe during CO adsorption-desorption. The IR bands for CO ad-species on the Pd shell suggest that the shell exposes mostly low-index surfaces, likely Pd(111) as the majority facet. Generally, the IR bands are blue-shifted as compared to conventional Pd/alumina catalysts, which may be due to the different support materials for Pd, Au versus Al2O3, and/or less strain of the Pd shell. Frequencies obtained from density functional calculations suggest the latter to be significant. Further, the catalytic CO oxidation ignition-extinction processes were followed by in situ IR, which shows the common CO poisoning and kinetic behavior associated with competitive adsorption of CO and O2 that is typically observed for noble metal catalysts.
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Severe-to-profound hearing loss (STPHL) can affect a person negatively in many ways. Audiological rehabilitation is important for these patients. Patients receiving cochlear implants make up less than 10% of this group but have been studied extensively. In 2005, a national registry for adult patients with STPHL was introduced in Sweden. Its purpose was to evaluate and improve rehabilitation for all patients with STPHL. Data from the Swedish registry for adult patients with STPHL were used to evaluate variables affecting the audiological rehabilitation. Previous published data from the registry were reviewed, and new data from the follow-up questionnaire were presented. More than 90% of patients rehabilitated with hearing aids experienced a good or very good benefit of audiological rehabilitation. Tinnitus and vertigo affected quality of life negatively and were reported by many patients with STPHL (41% and 31%) at follow-up. To maintain the high number of patients who find audiological rehabilitation beneficial, individualized treatment plans and timely re-evaluations are crucial. Tinnitus and vertigo need to be addressed repeatedly in the rehabilitation process.
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BACKGROUND: The prevalence of disabling hearing loss is increasing worldwide. However, previous studies on hearing loss prevalence have enrolled small populations or only provided estimates. AIM: To establish the prevalence of severe-to-profound hearing loss (STPHL) in the adult Swedish population and compare it with the cochlear implantation rate in Sweden. MATERIAL AND METHODS: We established a database containing over 15 million audiograms obtained from regions covering > 99% of the Swedish population by extracting audiogram data from the computer software application, Auditbase. We used this database to calculate the percentage of adult patients with bilateral hearing levels ≥ 70 dB. We collected data regarding cochlear implantations in Sweden from the National Board of Welfare and Health. RESULTS: The prevalence of STPHL in the adult Swedish population was 0.28%. There were regional variations in the prevalence and rate of cochlear implantation; however, there was no association between both parameters. CONCLUSIONS: This study presents an updated and reliable prevalence figure for STPHL in Sweden. SIGNIFICANCE: Patients with STPHL have extensive rehabilitation requirements; accordingly, it is important to determine the accurate prevalence of STPHL to inform the allocation of adequate resources.
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Implantación Coclear , Implantes Cocleares , Sordera , Pérdida Auditiva Sensorineural , Pérdida Auditiva , Percepción del Habla , Adulto , Sordera/cirugía , Pérdida Auditiva/epidemiología , Pérdida Auditiva/cirugía , Pérdida Auditiva Sensorineural/cirugía , Humanos , Prevalencia , Suecia/epidemiología , Resultado del TratamientoRESUMEN
Transplantation of pancreatic islet cells derived from human pluripotent stem cells is a promising treatment for diabetes. Despite progress in the generation of stem-cell-derived islets (SC-islets), no detailed characterization of their functional properties has been conducted. Here, we generated functionally mature SC-islets using an optimized protocol and benchmarked them comprehensively against primary adult islets. Biphasic glucose-stimulated insulin secretion developed during in vitro maturation, associated with cytoarchitectural reorganization and the increasing presence of alpha cells. Electrophysiology, signaling and exocytosis of SC-islets were similar to those of adult islets. Glucose-responsive insulin secretion was achieved despite differences in glycolytic and mitochondrial glucose metabolism. Single-cell transcriptomics of SC-islets in vitro and throughout 6 months of engraftment in mice revealed a continuous maturation trajectory culminating in a transcriptional landscape closely resembling that of primary islets. Our thorough evaluation of SC-islet maturation highlights their advanced degree of functionality and supports their use in further efforts to understand and combat diabetes.
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Trasplante de Islotes Pancreáticos , Islotes Pancreáticos , Células Madre Pluripotentes , Animales , Glucosa/metabolismo , Humanos , Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Trasplante de Islotes Pancreáticos/métodos , Ratones , Células Madre Pluripotentes/metabolismoRESUMEN
We have used grazing incidence X-ray absorption fine structure spectroscopy at the cobalt K-edge to characterize monolayer CoO films on Pt(111) under ambient pressure exposure to CO and O2, with the aim of identifying the Co phases present and their transformations under oxidizing and reducing conditions. X-ray absorption near edge structure (XANES) spectra show clear changes in the chemical state of Co, with the 2+ state predominant under CO exposure and the 3+ state predominant under O2-rich conditions. Extended X-ray absorption fine structure spectroscopy (EXAFS) analysis shows that the CoO bilayer characterized in ultrahigh vacuum is not formed under the conditions used in this study. Instead, the spectra acquired at low temperatures suggest formation of cobalt hydroxide and oxyhydroxide. At higher temperatures, the spectra indicate dewetting of the film and suggest formation of bulklike Co3O4 under oxidizing conditions. The experiments demonstrate the power of hard X-ray spectroscopy to probe the structures of well-defined oxide monolayers on metal single crystals under realistic catalytic conditions.
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Irisin is a myokine involved in glucose homeostasis. It is primarily expressed in skeletal muscle, but also in the pancreas. This study aimed to elucidate its presence and role in the islets of Langerhans-i.e., its effect on insulin and glucagon secretion as well as on blood flow in the pancreas. The precursor of irisin, fibronectin type III domain-containing protein 5 (FNDC5), was identified in rat and human islets by both qPCR and immunohistochemistry. Both α- and ß-cells stained positive for FNDC5. In human islets, we found that irisin was secreted in a glucose-dependent manner. Neither irisin nor an irisin-neutralizing antibody affected insulin or glucagon secretion from human or rat islets in vitro. The insulin and glucagon content in islets was not altered by irisin. The intravenous infusion of irisin in Sprague Dawley rats resulted in nearly 50% reduction in islet blood flow compared to the control. We conclude that irisin is an islet hormone that has a novel role in pancreatic islet physiology, exerting local vascular effects by diminishing islet blood flow without affecting insulin secretion per se.