Fast K-dimensional tree-structured vector quantization encoding method for image compression

This paper presents a fast K-dimensional tree-based search method to speed up the encoding process for vector quantization. The method is especially designed for very large codebooks and is based on a local search rather than on a global search including the whole feature space. The relations between the proposed method and several existing fast algorithms are discussed. Simulation results demonstrate that with little preprocessing and memory cost, the encoding time of the new algorithm has been reduced significantly while encoding quality remains the same with respect to other existing fast algorithms

Imaging predictors of incident heart failure: a systematic review and meta-analysis

BACKGROUND: Preventing the evolution of subclinical cardiac disease into overt heart failure is of paramount importance. Imaging techniques, particularly transthoracic echocardiography (TTE), are well suited to identify abnormalities in cardiac structure and function that precede the development of heart failure. METHODS: This meta-analysis provides a comprehensive evaluation of 32 studies from 11 individual cohorts, which assessed cardiac indices from TTE (63%), cardiovascular magnetic resonance (CMR; 34%) or cardiac computed tomography (CCT; 16%). Eligible studies focused on measures of left ventricular geometry and function and were highly heterogeneous. RESULTS: Among the variables that could be assessed through a meta-analytic approach, left ventricular systolic dysfunction, defined as left ventricular ejection fraction (LVEF) lower than 50%, and left ventricular dilation were associated with a five-fold [hazard ratio (HR) 4.76, 95% confidence interval (95% CI) 1.85-12.26] and three-fold (HR 3.14, 95% CI 1.37 -7.19) increased risk of heart failure development, respectively. Any degree of diastolic dysfunction conveyed an independent, albeit weaker, association with heart failure (HR 1.48, 95% CI 1.11-1.96), although there was only a trend for left ventricular hypertrophy in predicting incident heart failure (hazard ratio 2.85, 95% CI 0.82-9.85). CONCLUSION: LVEF less than 50%, left ventricular dilation and diastolic dysfunction are independent predictors of incident heart failure among asymptomatic individuals, while left ventricular hypertrophy seems less predictive. These findings may serve as a framework for implementing imaging-based screening strategies in patients at risk of heart failure and inform future studies testing preventive or therapeutic approaches aiming at thwarting or halting the progression from asymptomatic (preclinical) to overt heart failure

Metformin use in obese mothers is associated with improved cardiovascular profile in the offspring

BACKGROUND: Maternal obesity increases the risk for pregnancy complications and adverse neonatal outcome and it has also been associated with long lasting adverse effects in the offspring, including increased body fat mass, insulin resistance and increased risk for premature cardiovascular disease. Lifestyle interventions in pregnancy have produced none or modest effects in reducing adverse pregnancy outcomes in obese mothers. Metformin use in Obese Pregnant women trial was associated with reduced adverse pregnancy outcomes and had no effect on birthweight. However, the long-term implications of metformin on the health of offspring remain unknown. OBJECTIVE: The purpose of this study was to assess whether prenatal exposure to metformin can improve the cardiovascular profile and body composition in the offspring of obese mothers. STUDY DESIGN: In 151 children from the Metformin use in Obese-Pregnant women trial we measured body composition, peripheral blood pressure and arterial pulse wave velocity. Central hemodynamics (central blood pressure and augmentation index) were estimated using the Vicorder device. Left ventricular cardiac function and structure were assessed by echocardiography. RESULTS: Children were 3.9±1.0 years of age and 77 were exposed to metformin prenatally. There was no significant difference in peripheral blood pressure, arterial stiffness and body composition apart from gluteal and tricep circumferences which were lower in the metformin group (p<0.05). The metformin, compared to the placebo group, had lower central hemodynamics (mean adjusted decrease - 0.707mmHg for aortic systolic blood pressure, -1.65mmHg for aortic pulse pressure and -2.68% for augmentation index, p<0.05 for all) and lower left ventricular diastolic function (adjusted difference in left atrial area -0.525cm2, in isovolumic relaxation time -0.324msec and in pulmonary venous systolic wave 2.97cm/s, p<0.05 for all). There were no significant differences in metabolic profile between the groups. CONCLUSION: Children of obese mothers who were prenatally exposed to metformin, compared to those exposed to placebo, have lower central hemodynamic and cardiac diastolic indices. These results suggest that administration of metformin in obese pregnant women may potentially have a beneficial cardiovascular effect for their offspring

COVID-19 and myocarditis: a systematic review and overview of current challenges

Myocardial inflammation in COVID-19 has been documented. Its pathogenesis is not fully elucidated, but the two main theories foresee a direct role of ACE2 receptor and a hyperimmune response, which may also lead to isolated presentation of COVID-19-mediated myocarditis. The frequency and prognostic impact of COVID-19-mediated myocarditis is unknown. This review aims to summarise current evidence on this topic. We performed a systematic review of MEDLINE and Cochrane Library (1/12/19–30/09/20). We also searched clinicaltrials.gov for unpublished studies testing therapies with potential implication for COVID-19-mediated cardiovascular complication. Eligible studies had laboratory confirmed COVID-19 and a clinical and/or histological diagnosis of myocarditis by ESC or WHO/ISFC criteria. Reports of 38 cases were included (26 male patients, 24 aged &lt; 50&nbsp;years). The first histologically proven case was a virus-negative lymphocytic myocarditis; however, biopsy evidence of myocarditis secondary to SARS-CoV-2 cardiotropism has been recently demonstrated. Histological data was found in 12 cases (8 EMB and 4 autopsies) and CMR was the main imaging modality to confirm a diagnosis of myocarditis (25 patients). There was a substantial variability in biventricular systolic function during the acute episode and in therapeutic regimen used. Five patients died in hospital. Cause-effect relationship between SARS-CoV-2 infection and myocarditis is difficult to demonstrate. However, current evidence demonstrates myocardial inflammation with or without direct cardiomyocyte damage, suggesting different pathophysiology mechanisms responsible of COVID-mediated myocarditis. Established clinical approaches should be pursued until future evidence support different actions. Large multicentre registries are advisable to elucidate further

Adult intradural lipoma with tethered spinal cord syndrome

A 48-year-old woman presented to our imaging department with lumbar sciatica. The patient had a medical history of low back pain and spina bifida. A transverse section lumbar spine CT-scan, obtained with soft-tissue window setting (Fig. A, arrow) showed, a fat-density (45-HU), oblong, posterior intradural supracentimetric lesion, at level of L5-S1. The use of bone window setting revealed a spina bifida at L4-L5-S1 (Fig. B, arrow). Lumbar spine MRI performed shortly afterwards confirmed the presence of a posterior intradural supracentimetric lesion, at level of L5-S1, hyperintense on T1 (Fig. C, arrow) and T2, and hypointetense on T2 Stir weighted imaging (Fig. D, arrow), and showed that the filum terminale was attached to the aforementioned lesion. It also demonstrated that the conus medullaris was in an abdormally low position, set at the spinal level of L3-L4. Intradural spinal lipoma with tethered spinal cord was diagnosed. The patient will benefit from physiotherapy and a surgical option could be envisaged according to the clinical evolution

Response to 'Does smoking or alcohol cause early vascular damage in teenage years?'

This commentary refers to ‘Early vascular damage from smoking and alcohol in teenage years: the ALSPAC study’, by M. Charakida et al., 345–353

Remote ischemic preconditioning (RIPC) protects against endothelial dysfunction in a human model of systemic inflammation: a randomized clinical trial

Objective: Inflammation, oxidative stress, and endothelial dysfunction are known to contribute to ischemia-reperfusion injury. Remote ischemic preconditioning (RIPC) protects from endothelial dysfunction and the damage induced by ischemia-reperfusion. Using intensive periodontal treatment (IPT), an established human model of acute systemic inflammation, we investigated whether RIPC prevents endothelial dysfunction and modulates systemic levels of inflammation and oxidative stress. Approach and Results: Forty-nine participants with periodontitis were randomly allocated to receive either 3 cycles of ischemia-reperfusion on the upper limb (N=24, RIPC) or a sham procedure (N=25, control) before IPT. Endothelial function assessed by flow-mediated dilatation of the brachial artery, inflammatory cytokines, markers of vascular injury, and oxidative stress were evaluated at baseline, day 1, and day 7 after IPT. Twenty-four hours post-IPT, the RIPC group had lower levels of IL-10 (interleukin-10) and IL-12 (interleukin-12) compared with the control group (P<0.05). RIPC attenuated the IPT-induced increase in IL-1β (interleukin-1β), E-selectin, sICAM-3 (soluble intercellular adhesion molecule 3), and sTM (soluble thrombomodulin) levels between the baseline and day 1 (P for interaction <0.1). Conversely, oxidative stress was differentially increased at day1 in the RIPC group compared with the control group (P for interaction <0.1). This was accompanied by a better flow-mediated dilatation (mean difference 1.75% [95% CI, 0.428–3.07], P=0.011). After 7 days from IPT, most of the inflammatory markers, endothelial-dependent and -independent vasodilation, were similar between groups. Conclusions: RIPC prevented acute endothelial dysfunction by modulation of inflammation and oxidation processes in patients with periodontitis following exposure to an acute inflammatory stimulus

Predictors of adverse prognosis in COVID-19: A systematic review and meta-analysis

Background: Identification of reliable outcome predictors in coronavirus disease 2019 (COVID-19) is of paramount importance for improving patient's management. Methods: A systematic review of literature was conducted until 24 April 2020. From 6843 articles, 49 studies were selected for a pooled assessment; cumulative statistics for age and sex were retrieved in 587&nbsp;790 and 602&nbsp;234 cases. Two endpoints were defined: (a) a composite outcome including death, severe presentation, hospitalization in the intensive care unit (ICU) and/or mechanical ventilation; and (b) in-hospital mortality. We extracted numeric data on patients’ characteristics and cases with adverse outcomes and employed inverse variance random-effects models to derive pooled estimates. Results: We identified 18 and 12 factors associated with the composite endpoint and death, respectively. Among those, a history of CVD (odds ratio (OR)&nbsp;=&nbsp;3.15, 95% confidence intervals (CIs) 2.26-4.41), acute cardiac (OR&nbsp;=&nbsp;10.58, 5.00-22.40) or kidney (OR&nbsp;=&nbsp;5.13, 1.78-14.83) injury, increased procalcitonin (OR&nbsp;=&nbsp;4.8, 2.034-11.31) or D-dimer (OR&nbsp;=&nbsp;3.7, 1.74-7.89), and thrombocytopenia (OR&nbsp;=&nbsp;6.23, 1.031-37.67) conveyed the highest odds for the adverse composite endpoint. Advanced age, male sex, cardiovascular comorbidities, acute cardiac or kidney injury, lymphocytopenia and D-dimer conferred an increased risk of in-hospital death. With respect to the treatment of the acute phase, therapy with steroids was associated with the adverse composite endpoint (OR&nbsp;=&nbsp;3.61, 95% CI 1.934-6.73), but not with mortality. Conclusions: Advanced age, comorbidities, abnormal inflammatory and organ injury circulating biomarkers captured patients with an adverse clinical outcome. Clinical history and laboratory profile may then help identify patients with a higher risk of in-hospital mortality