192 research outputs found
REFRACTIVE INDEX SENSITIVITY IN THINNED UV AND ARC INDUCED LONG-PERIOD GRATINGS: A COMPARATIVE STUDY
Multipoint temperature monitoring of microwave thermal ablation in bones through fiber bragg grating sensor arrays
Bones are a frequent site of metastases that cause intolerable cancer-related pain in 90% of patients, making their quality of life poor. In this scenario, being able to treat bone oncology patients by means of minimally invasive techniques can be crucial to avoid surgery-related risks and decrease hospitalization times. The use of microwave ablation (MWA) is gaining broad clinical acceptance to treat bone tumors. It is worth investigating temperature variations in bone tissue undergoing MWA because the clinical outcomes can be inferred from this parameter. Several feasibility studies have been performed, but an experimental analysis of the temperature trends reached into the bone during the MWA has not yet been assessed. In this work, a multi-point temperature study along the bone structure during such treatment is presented. The study has been carried out on ex vivo bovine femur and tibia, subjected to MWA. An overall of 40 measurement points covering a large sensing area was obtained for each configuration. Temperature monitoring was performed by using 40 fiber Bragg grating (FBGs) sensors (four arrays each housing 10 FBGs), inserted into the bones at specific distances to the microwave antenna. As result, the ability of this experimental multi-point monitoring approach in tracking temperature variations within bone tissue during MWA treatments was shown. This study lays the foundations for the design of a novel approach to study the effects of MWA on bone tumors. As consequence, the MWA treatment settings could be optimized in order to maximize the treatment effects of such a promising clinical application, but also customized for the specific tumor and patient
Glucosamine-induced endoplasmic reticulum stress affects GLUT4 expression via activating transcription factor 6 in rat and human skeletal muscle cells
AIMS/HYPOTHESIS: Glucosamine, generated during hyperglycaemia, causes insulin resistance in different cells. Here we sought to evaluate the possible role of endoplasmic reticulum (ER) stress in the induction of insulin resistance by glucosamine in skeletal muscle cells. METHODS: Real-time RT-PCR analysis, 2-deoxy-D: -glucose (2-DG) uptake and western blot analysis were carried out in rat and human muscle cell lines. RESULTS: In both rat and human myotubes, glucosamine treatment caused a significant increase in the expression of the ER stress markers immunoglobulin heavy chain-binding protein/glucose-regulated protein 78 kDa (BIP/GRP78 [also known as HSPA5]), X-box binding protein-1 (XBP1) and activating transcription factor 6 (ATF6). In addition, glucosamine impaired insulin-stimulated 2-DG uptake in both rat and human myotubes. Interestingly, pretreatment of both rat and human myotubes with the chemical chaperones 4-phenylbutyric acid (PBA) or tauroursodeoxycholic acid (TUDCA), completely prevented the effect of glucosamine on both ER stress induction and insulin-induced glucose uptake. In both rat and human myotubes, glucosamine treatment reduced mRNA and protein levels of the gene encoding GLUT4 and mRNA levels of the main regulators of the gene encoding GLUT4 (myocyte enhancer factor 2 a [MEF2A] and peroxisome proliferator-activated receptor-gamma coactivator 1alpha [PGC1alpha]). Again, PBA or TUDCA pretreatment prevented glucosamine-induced inhibition of GLUT4 (also known as SLC2A4), MEF2A and PGC1alpha (also known as PPARGC1A). Finally, we showed that overproduction of ATF6 is sufficient to inhibit the expression of genes GLUT4, MEF2A and PGC1alpha and that ATF6 silencing with a specific small interfering RNA is sufficient to completely prevent glucosamine-induced inhibition of GLUT4, MEF2A and PGC1alpha in skeletal muscle cells. CONCLUSIONS/INTERPRETATION: In this work we show that glucosamine-induced ER stress causes insulin resistance in both human and rat myotubes and impairs GLUT4 production and insulin-induced glucose uptake via an ATF6-dependent decrease of the GLUT4 regulators MEF2A and PGC1alpha
An approach to prevent frailty in community dwelling older adults: a pilot study performed in Campania region in the framework of the PERSSILAA project
We developed and tested an innovative physical
training method in older adults that embeds the gym
program into everyday life in the most conservative
way possible. Physical training was included in the
activities of local parishes where older women from
Southern Italy spend most of their free time and was
delivered by trained physical therapists with the
support of an ICT tool known as CoCo. 113 older
women (aged 72.0 [69.0-75.0] years) noncompliant
to conventional exercise programs participated to
the study. 57 of them underwent the final
anthropometric assessment and 50 the final physical
tests. In study completers handgrip strength and
physical performance evaluated with the chair-stand,
the two minutes step and the chair-sit and -reach
tests significantly improved. Quality of life as
evaluated with the EuroQol-5dimension (EQ-5D)
questionnaire improved as well. In conclusion, a
training program designed to minimally impact on
life habits of older people is effective in improving
fitness in patients noncompliant to other to physical
exercise programs
ENPP1 Affects Insulin Action and Secretion: Evidences from In Vitro Studies
The aim of this study was to deeper investigate the mechanisms through which
ENPP1, a negative modulator of insulin receptor (IR) activation, plays a role on
insulin signaling, insulin secretion and eventually glucose metabolism. ENPP1
cDNA (carrying either K121 or Q121 variant) was transfected in HepG2 liver-, L6
skeletal muscle- and INS1E beta-cells. Insulin-induced IR-autophosphorylation
(HepG2, L6, INS1E), Akt-Ser473,
ERK1/2-Thr202/Tyr204 and GSK3-beta Ser9
phosphorylation (HepG2, L6), PEPCK mRNA levels (HepG2) and
2-deoxy-D-glucose uptake (L6) was studied. GLUT 4 mRNA
(L6), insulin secretion and caspase-3 activation (INS1E) were also investigated.
Insulin-induced IR-autophosphorylation was decreased in HepG2-K, L6-K, INS1E-K
(20%, 52% and 11% reduction vs. untransfected cells) and
twice as much in HepG2-Q, L6-Q, INS1E-Q (44%, 92% and 30%).
Similar data were obtained with Akt-Ser473,
ERK1/2-Thr202/Tyr204 and GSK3-beta Ser9 in
HepG2 and L6. Insulin-induced reduction of PEPCK mRNA was progressively lower in
untransfected, HepG2-K and HepG2-Q cells (65%, 54%, 23%).
Insulin-induced glucose uptake in untransfected L6 (60% increase over
basal), was totally abolished in L6-K and L6-Q cells. GLUT 4 mRNA was slightly
reduced in L6-K and twice as much in L6-Q (13% and 25% reduction
vs. untransfected cells). Glucose-induced insulin secretion was 60%
reduced in INS1E-K and almost abolished in INS1E-Q. Serum deficiency activated
caspase-3 by two, three and four folds in untransfected INS1E, INS1E-K and
INS1E-Q. Glyburide-induced insulin secretion was reduced by 50% in
isolated human islets from homozygous QQ donors as compared to those from KK and
KQ individuals. Our data clearly indicate that ENPP1, especially when the Q121
variant is operating, affects insulin signaling and glucose metabolism in
skeletal muscle- and liver-cells and both function and survival of insulin
secreting beta-cells, thus representing a strong pathogenic factor predisposing
to insulin resistance, defective insulin secretion and glucose metabolism
abnormalities
Sensing characteristics of long period gratings in hollow core fiber fabricated via electrode arc discharge
This paper reports on the fabrication of Long Period Gratings (LPGs) in hollow-core air-silica photonic bandgap fibers (HC-PCFs) by using pressure assisted Electrode Arc Discharge (EAD) technique. In particular, the fabrication procedure relies on the combined use of EAD step, to locally heat the HC fiber, and of a static pressure (slightly higher than the external one) inside the fiber holes, to modify the holes. Here, the experimental fabrication of LPG prototypes with different periods and lengths are discussed. And, the sensitivity of LPGs in HC-PCF to environmental parameters such as strain, temperature and static pressure are presented and discussed
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