2,384 research outputs found
Frequency of predischarge ventricular arrhythmias in postmyocardial infarction patients depends on residual left ventricular pump performance and is independent of the occurrence of acute reperfusion
AbstractObjective. To test whether acute reperfusion of the infarct-related vessel after an acute myocardial infarction is associated with a subsequent reduction in spontaneous ventricular arrhythmias that is independent of ventricular ejection fraction, 1,944 patients from the GISSI-2 study population were studied. The patients were selected on the basis of a first myocardial infarction and the availability of two-dimensional echocardiographic ejection fraction and data on the number of premature ventricular contractions per hour on Holter monitoring.Background. It has been suggested that postthrombolytic reperfusion of the culprit vessel may be associated with an increased electrical stability of the infarcted heart, irrespective of its residual pump performance.Methods. The predischarge relation between ejection fraction and number of premature ventricular contractions per hour was plotted according to the occurrence (1,309 ptients) or not (635 patients) of acute reperfusion, identified noninvasively according to the modifications of the ST segment in serial electrocardiograms obtained in the first 24 h after infarction.Results. The frequency of premature ventricular contractions increased in a linear fashion with decreasing ejection fraction in both cohorts (p < 0.005 and p < 0.0001); however, there was no significant difference between the slops and the intercepts of the two regression lines, so that the relation between ejection fraction and number of premature ventricular contractions per hour could be adequately described by a single equation: y (number of premature ventricular contractions) = 33.0 - 0.42x (ejection fraction) (r = −0.107, p < 0.0001). The results were the same even when differences between group characteristics were accounted for in a multiple regression model.Conclusions. It is concluded that 1) the number of premature ventricular contractions per hour after an acute myocardial infarction is dependent in a linear, inverse fashion on the residual ventricular ejection fraction, and 2) this relation is independent of the occurrence of reperfusion in the acute phase of infarction
Exactly quantized dynamics of classical incommensurate sliders
We report peculiar velocity quantization phenomena in the classical motion of
an idealized 1D solid lubricant, consisting of a harmonic chain interposed
between two periodic sliders. The ratio v_cm/v_ext of the chain center-of-mass
velocity to the externally imposed relative velocity of the sliders stays
pinned to exact "plateau" values for wide ranges of parameters, such as sliders
corrugation amplitudes, external velocity, chain stiffness and dissipation, and
is strictly determined by the commensurability ratios alone. The phenomenon is
explained by one slider rigidly dragging the kinks that the chain forms with
the other slider. Possible consequences of these results for some real systems
are discussed.Comment: 5 pags 4 fig
Modelo matemático e algoritmo de apoio para auxílio ao sequenciamento e à programação de lavra com alocação de equipamentos de carga
This paper focuses on the sequencing and scheduling problem of open pit mining,\ud
with the allocation of loading equipment considering a medium-term horizon.\ud
This study considers the existence of a heterogeneous loading equipment fleet and two\ud
types of mineable material, namely ore or waste rock. For the mining of ore, the following\ud
requirements are taken under consideration: the mixture quality, a crusher, the\ud
processing plant capacity and a stockpile, called ROM stockpile. In this context, we\ud
present a mathematical model in mixed integer linear programming, supported by an\ud
algorithm that is responsible for moving the time horizon at each model run, aiming\ud
to generate mining orders resolved with optimality. Together, these orders describe the\ud
loading equipment mining plan.Esse trabalho tem seu foco no problema de sequenciamento e programação da\ud
lavra em mina a céu aberto com a alocação de equipamentos de carregamento, considerando\ud
um período de médio prazo. Nesse estudo, considera-se a existência de uma\ud
frota heterogênea de equipamentos de carga e de dois tipos de materiais lavráveis,\ud
sendo minério ou estéril. Para a lavra de minério, são contemplados requisitos de\ud
qualidade da mistura, um britador, capacidade da usina de beneficiamento e uma pilha\ud
de estoque, denominada pilha de ROM. Nesse contexto, apresenta-se um modelo\ud
matemático em programação linear inteira mista, apoiado por um algoritmo responsável\ud
por mover o horizonte de tempo, a cada execução do modelo, com intuito de\ud
gerar ordens de lavra resolvidas com otimalidade. Juntas, essas ordens descreverão o\ud
plano de lavra dos equipamentos de carga
High-performance liquid chromatography/high-resolution mass spectrometry for the characterization of transformation products of ionic liquids
Total or near-total thyroidectomy versus subtotal thyroidectomy for multinodular non-toxic goitre in adults
Background
Total thyroidectomy (TT) and subtotal thyroidectomy (ST) are worldwide treatment options for multinodular non-toxic goitre in adults. Near TT, defined as a postoperative thyroid remnant less than 1 mL, is supposed to be a similarly effective but safer option than TT. ST has been shown to be marginally safer than TT, but it may leave an undetected thyroid cancer in place.
Objectives
The objective was to assess the effects of total or near-total thyroidectomy compared to subtotal thyroidectomy for multinodular non-toxic goitre.
Search methods
We searched the Cochrane Library, MEDLINE, PubMed, EMBASE, as well as the ICTRP Search Portal and ClinicalTrials.gov. The date of the last search was 18 June 2015 for all databases. No language restrictions were applied.
Selection criteria
Two review authors independently scanned the abstract, title or both sections of every record retrieved to identify randomised controlled trials (RCTs) on thyroidectomy for multinodular non-toxic goitre for further assessment.
Data collection and analysis
Two review authors independently extracted data, assessed studies for risk of bias and evaluated overall study quality utilising the GRADE instrument. We calculated the odds ratio (OR) and corresponding 95% confidence interval (CI) for dichotomous outcomes. A random-effects model was used for pooling data.
Main results
We examined 1430 records, scrutinized 14 full-text publications and included four RCTs. Altogether 1305 participants entered the four trials, 543 participants were randomised to TT and 762 participants to ST. A total of 98% and 97% of participants finished the trials in the TT and ST groups, respectively. Two trials had a duration of follow-up between 12 and 39 months and two trials a follow-up of 5 and 10 years, respectively. Risk of bias across studies was mainly unknown for selection, performance and detection bias. Attrition bias was generally low and reporting bias high for some outcomes. In the short-term postoperative period no deaths were reported for both TT and ST groups. However, longer-term data on all-cause mortality were not reported (1284 participants; 4 trials; moderate quality evidence). Goiter recurrence was lower in the TT group compared to ST. Goiters recurred in 0.2% (1/425) of the TT group compared to 8.4% (53/632) of the ST group (OR 0.05 (95% CI 0.01 to 0.21); P < 0.0001; 1057 participants; 3 trials; moderate quality evidence). Re-intervention due to goitre recurrence was lower in the TT group compared to ST. Re-intervention was necessary in 0.5% (1/191) of TT patients compared to 0.8% (3/379)of ST patients (OR 0.66 (95% CI 0.07 to 6.38); P = 0.72; 570 participants; 1 trial; low quality evidence). The incidence of permanent recurrent laryngeal nerve palsy was lower for ST compared with TT. Permanent recurrent laryngeal nerve palsy occurred in 0.8% (6/741) of ST patients compared to 0.7% (4/543) of TT patients (OR 1.28, (95% CI 0.38 to 4.36); P = 0.69; 1275 participants; 4 trials; low quality evidence). The incidence of permanent hypoparathyroidism was lower for ST compared with TT. Permanent hypoparathyroidism occurred in 0.1% (1/741) of ST patients compared to 0.6% (3/543) of TT patients (OR 3.09 (95% CI 0.45 to 21.36); P = 0.25; 1275 participants: 4 trials; low quality evidence). The incidence of thyroid cancer was lower for ST compared with TT. Thyroid cancer occurred in 6.1% (41/669) of ST patients compared to 7.3% (34/465)of TT patients (OR 1.32 (95% CI 0.81 to 2.15); P = 0.27; 1134 participants; 3 trials; low quality evidence). No data on health-related quality of life or socioeconomic effects were reported in the included studies.
Authors' conclusions
The body of evidence on TT compared with ST is limited. Goiter recurrence is reduced following TT. The effects on other key outcomes such as re-interventions due to goitre recurrence, adverse events and thyroid cancer incidence are uncertain. New long-term RCTs with additional data such as surgeons level of experience, treatment volume of surgical centres and details on techniques used are needed
Contrast-Enhanced Ultrasound: a Simple and Effective Tool in Defining a Rapid Diagnostic Work-up for Small Nodules Detected in Cirrhotic Patients during Surveillance
Disappearance of portal blood flow and arterial vascularization is the hallmark of hepatocarcinogenesis. The capability of a dynamic imaging modality detecting arterial hypervascularization of small nodules is crucial to promote a rapid diagnostic and therapeutic work-up improving survival. We aimed to evaluate the capability of CEUS to detect arterial vascularization of ≤ 2 cm HCC nodules arising during surveillance so as to shorten the diagnostic and therapeutic work-up
The Dlx5 and Foxg1 transcription factors, linked via miRNA-9 and -200, are required for the development of the olfactory and GnRH system
Induction of Functional Neovascularization by Combined VEGF and Angiopoietin-1 Gene Transfer Using AAV Vectors
Vectors based on the adeno-associated virus (AAV) deliver therapeutic genes to muscle and heart at high efficiency and maintain transgene expression for long periods of time. Here we report about the synergistic effect on blood vessel formation of AAV vectors expressing the 165 aa isoform of vascular endothelial growth factor (VEGF165), a powerful activator of endothelial cells, and of angiopoietin-1 (Ang-1), which is required for vessel maturation. High titer AAV-VEGF165 and AAV-Ang-1 vector preparations were injected either alone or in combination in the normoperfused tibialis anterior muscle of rats. Long term expression of VEGF165 determined massive cellular infiltration of the muscle tissues over time, with the formation of a large set of new vessels. Strikingly, some of the cells infiltrating the treated muscles were found positive for markers of activated endothelial precursors (VEGFR-2/KDR and Tie-2) and for c-kit, an antigen expressed by pluripotent bone marrow stem cells. Expression of VEGF165 eventually resulted in the formation of structured vessels surrounded by a layer of smooth muscle cells. Presence of these arteriolae correlated with significantly increased blood perfusion in the injected areas. Co-expression of VEGF165 with angiopoietin-1-which did not display angiogenic effect per se-remarkably reduced leakage of vessels produced by VEGF165 alone
Microwave Ablation in Intermediate Hepatocellular Carcinoma in Cirrhosis: An Italian Multicenter Prospective Study
Background and Aims:
To report long-term results in treatment of intermediate hepatocellular carcinoma (HCC) in cirrhotics using new high-powered microwaves (MWS) ablation alone.
Methods:
This multicenter study included 215 cirrhotics (age range: 67-84 years; 137 males; 149 Child A, 66 Child B) who underwent percutaneous ultrasound-guided high-powered MWS ablation instead of transarterial chemoembolization. Among the patient population, 109 had a single nodule (Ø 5.3-8 cm) [group A], 70 had 2 nodules (Ø 3-6 cm) [group B] and 36 had 3-5 nodules (Ø 1.5-6.8 cm) [group C]. MWS ablation efficacy was evaluated using enhanced-computed tomography and/or magnetic resonance imaging. Primary end-point was 5-year cumulative overall survival (OS).
Results:
On enhanced-computed tomography and/or magnetic resonance imaging, complete ablation rates were 100% for 1.5-3.5 cm nodules. In nodules >3.5-5 cm, it was 89% for the first ablation and 100% for the second. For lesions >5-8 cm, ablation was up to 92%. Overall, 1-, 3- and 5-year survival rates were 89, 60, and 21%, respectively. The cumulative OS rate of group A was 89%, 66% and 34% at 1, 3 and 5 years. The cumulative OS rate of group B was 88%, 60% and 11% at 1, 3 and 5 years. The cumulative OS rate of group C was 86%, 55% and 0%. The 5-year survival rate was significantly different among the groups (p <0.001). One patient died from rupture of HCC. Upon multivariate analysis, preablation total bilirubin >1.5 mg/dL was an independent factor for predicting lower survival.
Conclusions:
Percutaneous MWS ablation of intermediate HCC is safe and effective in inducing large volume of necrosis in intermediate HCC nodules, providing long-term survival rates similar to transarterial chemoembolization. Preablation total bilirubin >1.5 mg/dL as expression of liver function reserve is the main factor predicting a worse outcome
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