113 research outputs found
The Impact of Inflammation on Pancreatic β-Cell Metabolism, Function and Failure in T1DM and T2DM: Commonalities and Differences
Physiological regulation of the heat shock response by glutamine: implications for chronic low-grade inflammatory diseases in age-related conditions
The effects of aerobic exercise training at two different intensities in obesity and type 2 diabetes: implications for oxidative stress, low-grade inflammation and nitric oxide production
Aims To investigate the effect of 16 weeks of aerobic training performed at two different intensities on nitric oxide (tNOx) availability and iNOS/nNOS expression, oxidative stress (OS) and inflammation in obese humans with or without type 2 diabetes mellitus (T2DM).
Methods Twenty-five sedentary, obese (BMI > 30 kg/m(2)) males (52.8 +/- 7.2 years); 12 controls versus 13 T2DM were randomly allocated to four groups that exercised for 30 min, three times per week either at low (Fat-Max; 30-40 % VO2max) or moderate (T-vent; 55-65 % VO2max) intensity. Before and after training, blood and muscle samples (v. lateralis) were collected.
Results Baseline erythrocyte glutathione was lower (21.8 +/- 2.8 vs. 32.7 +/- 4.4 nmol/ml) and plasma protein oxidative damage and IL-6 were higher in T2DM (141.7 +/- 52.1 vs. 75.5 +/- 41.6 nmol/ml). Plasma catalase increased in T2DM after T-vent training (from 0.98 +/- 0.22 to 1.96 +/- 0.3 nmol/min/ml). T2DM groups demonstrated evidence of oxidative damage in response to training (elevated protein carbonyls). Baseline serum tNOx were higher in controls than T2DM (18.68 +/- 2.78 vs. 12.34 +/- 3.56 mu mol/l). Training at T-vent increased muscle nNOS and tNOx in the control group only. Pre-training muscle nNOS was higher in controls than in T2DMs, while the opposite was found for iNOS. No differences were found after training for plasma inflammatory markers.
Conclusion Exercise training did not change body composition or aerobic fitness, but improved OS markers, especially when performed at T-vent. Non-diabetics responded to T-vent training by increasing muscle nNOS expression and tNOx levels in skeletal muscle while these parameters did not change in T2DM, perhaps due to higher insulin resistance (unchanged after intervention)
L-Arginine Is Essential for Pancreatic b-Cell Functional Integrity, Metabolism and Defense From Inflammatory Challenge
In this work, our aim was to determine whether L-arginine (a known insulinotropic amino acid) can promote a shift of b-cell intermediary metabolism favoring glutathione (GSH) and glutathione disulfide (GSSG) antioxidant responses, stimulus–secretion coupling and functional integrity. Clonal BRIN-BD11 b-cells and mouse islets were cultured for 24 h at various L-arginine concentrations (0–1.15 mmol/l) in the absence or presence of a proinflammatory cytokine cocktail (interleukin 1b, tumour necrosis factor a and interferon g). Cells were assessed for viability, insulin secretion, GSH, GSSG, glutamate, nitric oxide (NO), superoxide, urea, lactate and for the consumption of glucose and glutamine. Protein levels of NO synthase-2, AMP-activated protein kinase (AMPK) and the heat shock protein 72 (HSP72) were also evaluated. We found that L-arginine at 1.15 mmol/l attenuated the loss of b-cell viability observed in the presence of proinflammatory cytokines. L-Arginine increased total cellular GSH and glutamate levels but reduced the GSSG/GSH ratio and glutamate release. The amino acid stimulated glucose consumption in the presence of cytokines while also stimulating AMPK phosphorylation and HSP72 expression. Proinflammatory cytokines reduced, by at least 50%, chronic (24 h) insulin secretion, an effect partially attenuated by L-arginine. Acute insulin secretion was robustly stimulated by L-arginine but this effect was abolished in the presence of cytokines. We conclude that L-arginine can stimulate b-cell insulin secretion, antioxidant and protective responses, enabling increased functional integrity of b-cells and islets in the presence of proinflammatory cytokines. Glucose consumption and intermediary metabolism were increased by L-arginine. These results highlight the importance of L-arginine availability for b-cells during inflammatory challeng
Effects of acute aerobic, resistance and combined exercises on 24-h glucose variability and skeletal muscle signalling responses in type 1 diabetics
Purpose: To compare the effect of high-intensity aerobic (AER), resistance (RES), and combined (COMB: RES + AER) exercise, on interstitial glucose (IG) variability and skeletal muscle signalling pathways in type 1 diabetes (T1D).
Methods: T1D participants (6 M/6F) wore a flash glucose monitoring system in four randomized sessions: one control (CONT), and one AER, RES and COMB (40 min each). Mean amplitude of glycemic excursions (MAGE), standard deviation (SD) and coefficient variation (CV) of IG were used to compare the 24 h post-exercise IG variability. Blood and muscle samples were collected to compare exercise-induced systemic and muscle signalling responses related to metabolic, growth and inflammatory adaptations.
Results: Both RES and COMB decreased the 24 h MAGE compared to CONT; additionally, COMB decreased the 24 h SD and CV. In the 6-12 h post-exercise, all exercise modalities reduced the IG CV while SD decreased only after COMB. Both AER and COMB stimulated the PGC-1α mRNA expression and promoted the splicing of IGF-1Ea variant, while Akt and p38MAPK phosphorylation increased only after RES and COMB. Additionally, COMB enhanced eEF2 activation and RES increased myogenin and MRF4 mRNA expression. Blood lactate and glycerol levels and muscle IL-6, TNF-α, and MCP-1 mRNAs increased after all exercise sessions, while serum CK and LDH level did not change.
Conclusion: COMB is more effective in reducing IG fluctuations compared to single-mode AER or RES exercise. Moreover, COMB simultaneously activates muscle signalling pathways involved in substrate metabolism and anabolic adaptations, which can help to improve glycaemic control and maintain muscle health in T1D
Padrão de resistência antimicrobiana em culturas ambulatoriais de urina em mulheres no sul do Brasil – comunicação breve de um estudo transversal
Objetivo: O aumento da resistĂŞncia aos antibiĂłticos (AR) Ă© um fenĂ´meno global com variações regionais. Esta pesquisa tem como objetivo descrever a AR em culturas de urina de mulheres oriundas da comunidade em uma cidade sul-brasileira.MĂ©todos: Um estudo de centro Ăşnico, transversal e retrospectivo em culturas de urina oriundas da comunidade. O principal desfecho foi o perfil de AR de bactĂ©rias isoladas de uroculturas ambulatoriais.Resultados: De 4.011 culturas de urina, 524 foram positivas (91% de mulheres). As bactĂ©rias mais frequentemente isoladas em mulheres foram Escherichia coli (67,0%) e Klebsiella spp. (19,4%). E. coli apresentou baixa resistĂŞncia Ă nitrofurantoĂna (3,7%), moderada a levofloxacina (15,6%), amoxacilina-clavulonato (16,4%) e ciprofloxacina (17,4%) e alta ao trimetoprim-sulfametoxazol (26,9%) entre mulheres.Conclusões: A nitrofurantoĂna parece ser a melhor escolha para o tratamento empĂrico das infecções do trato urinário inferior em mulheres, enquanto as sulfonamidas nĂŁo sĂŁo mais uma opção, uma vez que a resistĂŞncia de E. coli a essa droga Ă© superior a 20%.
Palavras-chave: Infecções urinárias. Infecções comunitárias adquiridas. Resistência microbiana a medicamentos. Brasil. Escherichia coli
Beyond frequency: Evaluating the validity of assessing the context, duration, ability and botherement of depression and anxiety symptoms in south Brazil
Assessment tools for depression and anxiety usually inquire about frequency of symptoms. However, evidence suggests that different question framings might trigger different responses. Our aim is to test if asking about symptom’s context, ability, duration and botherement adds validity to PHQ-9, GAD-7 and PROMIS depression and anxiety. Participants came from two cross-sectional convenience-sampled surveys (N=1,871) of adults (66% females, aged 33.4 ± 13.2), weighted to approximate with the state-level population. We examined measurement invariance across the different question frames, estimated whether framing affected mean scores, and tested their independent validity using covariate-adjusted and sample-weighted structural equation models. Validity was tested using tools assessing general disability, alcohol use, loneliness, well-being, grit, and frequency-based questions from depression and anxiety questionnaires. A bifactor model was applied to test the internal consistency of the question-frames under the presence of a general factor (i.e., depression or anxiety). Measurement invariance was supported across the different frames. Framing questions as ability (i.e., “how easily…”) produced a higher score, compared with framing by context (i.e., “in which daily situations…”). Construct and criterion validity analysis demonstrate that variance explained using multiple question frames were similar to using only one. We detected a strong overarching factor for each instrument, with little variances left to be explained by the question frame. Therefore, it is unlikely that using different adverbial phrasings can help clinicians and researchers to improve their ability to detect depression or anxiety.Key words: PHQ-9, GAD-7, PROMIS, mental health questionnaire, question frame.<br/
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
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