972 resultados para Standing, Guy
Resumo:
Background: To investigate indocyanine green angiography (ICGA) findings in patients with long-standing Vogt-Koyanagi-Harada (VKH) disease and their correlation with disease activity on clinical examination as well as with systemic corticosteroid therapy. Methods: Twenty-eight patients (51 eyes) with long-standing (>= 6 months from disease onset) VKH disease whose treatment was tapered based only in clinical features were prospectively included at a single center in Brazil. All patients underwent standardized clinical evaluation, which included fundus photography, fluorescein angiography and ICGA. Clinical disease activity was determined based in the Standardization in Uveitis Nomenclature Working Group. Fisher exact test and logistic regression models were used for statistical analysis. Results: Disease-related choroidal inflammation on ICGA was observed in 72.5% (31 of 51 eyes). Angiographic findings suggestive of (choroidal and/or retinal) disease activity were not observed on FA. Clinically active disease based on clinical evaluation was observed in 41.2% (21 of 51 eyes). In these 21 eyes, disease-related choroidal inflammation on ICGA was observed in 76.2% (16 of 21 eyes); in the remaining eyes (without clinical active disease) disease-related choroidal inflammation on ICGA was observed in 70.0% (21 of 30 eyes). In respect to systemic corticosteroid therapy, 10 patients (18 of 51 eyes) were under treatment with prednisone. In these 10 (18 of 51 eyes) patients, disease-related choroidal inflammation on ICGA was observed in 83.3% (15 of 18 eyes); in the remaining patients (33 of 51 eyes) disease-related choroidal inflammation on ICGA was observed in 66.7% (22 of 33 eyes). Conclusion: ICGA findings suggestive of disease-related choroidal inflammation were observed in a considerable proportion of patients with long-standing VKH disease, independent of the inflammatory status of the disease on clinical examination or current use of systemic corticosteroid. Therefore, the current study reinforces the crucial role of ICGA to assist the management and treatment of patients with long-standing VKH disease.
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In questa tesi viene descritto lo studio delle fasi liquido-cristalline del 4-n-ottil-4-cianobifenile eseguito tramite simulazioni al calcolatore molecular dynamics, sia per campioni bulk che per film smectici sottili. Impiegando un campo di forze "molecular mechanics" precedentemente usato con successo per studiare sistemi composti da 250 molecole della serie degli n-cianobifenili (nCB, con n pari a 4-8 atomi di carbonio nella catena alifatica), si è simulato il comportamento di un sistema bulk di 750 molecole e di un film smectico di 1500 molecole. Nel primo caso, sottoponendo il campione a un graduale raffreddamento, si è osservata la formazione spontanea di fasi ordinate quali quella nematica e quella smectica. Nel secondo caso, invece, si è studiata l'influenza dell'interfaccia con il vuoto sull'ordine posizionale e orientazionale di film sottili di diverso spessore e temperatura. Si sono confrontate le proprietà di entrambi i sistemi simulati con i dati sperimentali disponibili in letteratura, confermando la bontà del modello nel riprodurre fedelmente le caratteristiche dei campioni reali.
Resumo:
L’infiammazione cronica è un fattore di rischio di insorgenza del cancro, e la citochina infiammatoria IL-6 gioca un ruolo importante nella tumorigenesi. In questo studio abbiamo dimostrato che L’IL-6 down-regola l'espressione e l'attività di p53. In linee cellulari umane, IL-6 stimola la trascrizione dell’rRNA mediante espressione della proteina c-myc a livello post-trascrizionale in un meccanismo p38MAPK-dipendente. L'up-regolazione della biogenesi ribosomiale riduce l'espressione di p53 attraverso l'attivazione della via della proteina ribosomale-MDM2. La down-regolazione di p53 produce l’acquisizione di modifiche fenotipiche e funzionali caratteristiche della epitelio mesenchimale di transizione, un processo associato a trasformazione maligna e progressione tumorale. I nostri dati mostrano che questi cambiamenti avvengono anche nelle cellule epiteliali del colon di pazienti affetti da colite ulcerosa, un esempio rappresentativo di una infiammazione cronica soggetta a trasformazione neoplastica, che scompaiono dopo trattamento con farmaci antinfiammatori. Questi risultati svelano un nuovo effetto oncogenico indotto dall’IL-6 che può contribuire notevolmente ad aumentare il rischio di sviluppare il cancro non solo in pazienti con infiammazioni croniche, ma anche in quei pazienti con condizioni patologiche caratterizzate da elevato livello di IL-6 nel plasma, quali l'obesità e e il diabete mellito di tipo 2.
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The research presented in this thesis was conducted to further the development of the stress wave method of nondestructively assessing the quality of wood in standing trees. The specific objective of this research was to examine, in the field, use of two stress wave nondestructive assessment techniques. The first technique examined utilizes a laboratory-built measurement system consisting of commercially available accelerometers and a digital storage oscilloscope. The second technique uses a commercially available tool that incorporates several technologies to determine speed of stress wave propagation in standing trees. Field measurements using both techniques were conducted on sixty red pine trees in south-central Wisconsin and 115 ponderosa pine trees in western Idaho. After in-situ measurements were taken, thirty tested red pine trees were felled and a 15-foot-long butt log was obtained from each tree, while all tested ponderosa pine trees were felled and an 8 1/2 -foot-long butt log was obtained, respectively. The butt logs were sent to the USDA Forest Products Laboratory and nondestructively tested using a resonance stress wave technique. Strong correlative relationships were observed between stress wave values obtained from both field measurement techniques. Excellent relationships were also observed between standing tree and log speed-of-sound values.
Resumo:
OBJECTIVE: To investigate the effect of plasma concentrations obtained by a low dose constant rate infusion (CRI) of racemic ketamine or S-ketamine on the nociceptive withdrawal reflex (NWR) in standing ponies. STUDY DESIGN: Prospective, blinded, cross-over study. ANIMALS: Six healthy 5-year-old Shetland ponies. METHODS: Ponies received either 0.6 mg kg(-1) racemic ketamine (group RS) or 0.3 mg kg(-1) S-ketamine (group S) intravenously (IV), followed by a CRI of 20 microg kg(-1)minute(-1) racemic ketamine (group RS) or 10 microg kg(-1)minute(-1) S-ketamine (group S) for 59 minutes. The NWR was evoked by transcutaneous electrical stimulation of a peripheral nerve before drug administration, 15 and 45 minutes after the start of the bolus injection and 15 minutes after the end of the CRI. Electromyographic responses were recorded and analysed. Arterial blood was collected before stimulation and plasma concentrations of ketamine and norketamine were measured enantioselectively using capillary electrophoresis. Ponies were video recorded and monitored to assess drug effects on behaviour, heart rate (HR), mean arterial blood pressure (MAP) and respiratory rate. RESULTS: The NWR was significantly depressed in group RS at plasma concentrations between 20 and 25 ng mL(-1) of each enantiomer. In group S, no significant NWR depression could be observed; plasma concentrations of S-ketamine (9-15 ng mL(-1)) were lower, compared to S-ketamine concentrations in group RS, although this difference was not statistically significant. Minor changes in behaviour, HR and MAP only occurred within the first 5-10 minutes after bolus drug administration in both groups. CONCLUSION: Antinociceptive activity in standing ponies, demonstrated as a depression of the NWR, could only be detected after treatment with racemic ketamine. S-ketamine may have lacked this effect as a result of lower plasma concentrations, a more rapid metabolism or a lower potency of S-ketamine in Equidae so further investigation is necessary.
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To assess bone mineral density (BMD) at different skeletal sites in women with hypothalamic or ovarian amenorrhea and the effect of estrogen-gestagen substitution on BMD we compared BMD of 21 amenorrheic patients with hypothalamic or ovarian amenorrhea with that of a control population of 123 healthy women. All amenorrheic patients were recruited from the outpatient clinic of the Division of Gynecological Endocrinology at the University of Berne, a public University Hospital. One hundred and twenty-three healthy, regularly menstruating women recruited in the Berne area served as a control group. BMD was measured using dual-energy X-ray absorptiometry (DXA). At each site where it was measured, mean BMD was lower in the amenorrheic group than in the control group. Compared with the control group, average BMD in the amenorrheic group was 85% at lumbar spine (p < 0.0001), 92% at femoral neck (p < 0.02), 90% at Ward's triangle (p < 0.03), 92% at tibial diaphysis (p < 0.0001) and 92% at tibial epiphysis (p < 0.03). Fifteen amenorrheic women received estrogen-gestagen replacement therapy (0.03 mg ethinylestradiol and 0.15 mg desogestrel daily for 21 days per month), bone densitometry being repeated within 12-24 months. An annual increase in BMD of 0.2% to 2.9% was noted at all measured sites, the level of significance being reached at the lumbar spine (p < 0.0012) and Ward's triangle (p < 0.033). In conclusion BMD is lower in amenorrheic young women than in a population of normally menstruating, age-matched women in both mainly trabecular (lumbar spine, Ward's triangle, tibial epiphysis) and mainly cortical bone (femoral neck, tibial diaphysis).(ABSTRACT TRUNCATED AT 250 WORDS)
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Catheter ablation for paroxysmal atrial fibrillation is a meanwhile established therapy option, which is most frequently performed using radiofrequency ablation. Mid-term success rate of 70 % are achievable with a single ablation procedure. However, the mechanistics of persistent atrial fibrillation are less well understood and catheter ablation is a far more challenging procedure. Different ablation approaches are being performed to treat persistent atrial fibrillation ranging from sole pulmonary vein isolation to additional ablation of fractionated electrograms aiming for termination of atrial fibrillation. Thus far, it has not been investigated which strategy is most successful in treating persistent atrial fibrillation. After extended ablation of atrial fibrillation, occurrence of organized atrial arrhythmias is not uncommon and can be successfully ablated. These consecutive arrhythmias can be considered as a next step towards stable sinus rhythm after repeat ablation. Improvement of mapping methods as well as a better understanding of mechanisms of atrial fibrillation may increase success rate of catheter ablation of persistent atrial fibrillation and may also help to improve success rate of these complex procedures.
Resumo:
Observations of the ozone profile by a ground-based microwave radiometer in Switzerland indicate a dominant 20-day oscillation in stratospheric ozone, possibly related to oscillations of the polar vortex edge during winter. For further understanding of the nature of the 20-day oscillation, the ozone data set of ERA Interim meteorological reanalysis is analyzed at the latitude belt of 47.5° N and in the time from 1979 to 2010. Spectral analysis of ozone time series at 7 hPa indicates that the 20-day oscillation is maximal at two locations: 7.5° E, 47.5° N and 60° E, 47.5° N. Composites of the stream function are derived for different phases of the 20-day oscillation of stratospheric ozone at 7 hPa in the Northern Hemisphere. The streamline at Ψ = −2 × 107 m2 s−1 is in the vicinity of the polar vortex edge. The other streamline at Ψ = 4 × 107 m2 s1 surrounds the Aleutian anticyclone and goes to the subtropics. The composites show 20-day period standing oscillations at the polar vortex edge and in the subtropics above Northern Africa, India, and China. The 20-day period standing oscillation above Aral Sea and India is correlated to the strength of the Aleutian anticyclone.