Myxoid liposarcoma: MRI features with histological correlation.

BACKGROUND AND AIMS: Myxoid liposarcoma is classified in the group of sarcomas with adipose differentiation, which is the second most common group of sarcomas. However, myxoid liposarcoma is not a homogeneous entity, because the behavior and clinical course of these tumours can vary widely. This study aimed to describe the magnetic resonance imaging (MRI) features of myxoid liposarcomas and to determine whether the MRI features are associated with the histologic grade and can differentiate between low-grade and high-grade tumours and thus help in clinical decision making. MATERIAL AND METHODS: We studied 36 patients with myxoid liposarcomas treated at our centre between 2010 and 2018. We analysed clinical variables (age, sex, and tumour site) and MRI features (size, depth, borders, fatty component, myxoid component, non-fatty/non-myxoid component, apparent diffusion coefficient (ADC), and type of enhancement after the administration of intravenous contrast material). We correlated the MRI features with the histologic grade and the percentage of round cells. RESULTS: In our series, patients with myxoid liposarcomas were mainly young adults (median age, 43 years). There were no differences between sexes; 97.2% were located in the lower limbs, 86.1% were deep, and 77.8% had well-defined borders. Of the 23 myxoid liposarcomas that contained no fat, 16 (69.6%) were high grade (p = 0.01). All the tumors with a myxoid component of less than 25% were high grade (p = 0.01); 83.3% of those with a non-fatty/non-myxoid component greater than 50% were high grade (p = 0.03) and 61.5% had more than 5% round cells (p = 0.01). Diffusion sequences were obtained in 14 of the 36 patients; ADC values were high (median, 2 × 10-3 mm2/s), although there were no significant associations between low-grade and high-grade tumours. Contrast-enhanced images were available for 30 (83.3%) patients; 83.3% of the tumours with heterogeneous enhancement were high grade (p = 0.01). CONCLUSIONS: MRI can be useful for differentiating between high- and low-grade myxoid liposarcomas and can help in clinical decision making.

Myxoid liposarcoma: MRI features with histological correlation. / Liposarcoma mixoide: características por resonancia magnética con correlación histológica.

BACKGROUND AND AIMS: Myxoid liposarcoma is classified in the group of sarcomas with adipose differentiation, which is the second most common group of sarcomas. However, myxoid liposarcoma is not a homogeneous entity, because the behavior and clinical course of these tumors can vary widely. This study aimed to describe the magnetic resonance imaging (MRI) features of myxoid liposarcomas and to determine whether the MRI features are associated with the histologic grade and can differentiate between low-grade and high-grade tumors and thus help in clinical decision making. MATERIAL AND METHODS: We studied 36 patients with myxoid liposarcomas treated at our center between 2010 and 2018. We analyzed clinical variables (age, sex, and tumor site) and MRI features (size, depth, borders, fatty component, myxoid component, non-fatty / non-myxoid component, apparent diffusion coefficient (ADC), and type of enhancement after the administration of intravenous contrast material). We correlated the MRI features with the histologic grade and the percentage of round cells. RESULTS: In our series, patients with myxoid liposarcomas were mainly young adults (median age, 43 years). There were no differences between sexes; 97.2% were located in the lower limbs, 86.1% were deep, and 77.8% had well-defined borders. Of the 23 myxoid liposarcomas that contained no fat, 16 (69.6%) were high grade (p=0.01). All the tumors with a myxoid component of less than 25% were high grade (p=0.01); 83.3% of those with a non-fatty / non-myxoid component greater than 50% were high grade (p=0.03) and 61.5% had more than 5% round cells (p=0.01). Diffusion sequences were obtained in 14 of the 36 patients; ADC values were high (median, 2 x 10-3 mm2/s), although there were no significant associations between low-grade and high-grade tumors. Contrast-enhanced images were available for 30 (83.3%) patients; 83.3% of the tumors with heterogeneous enhancement were high grade (p=0.01). CONCLUSIONS: MRI can be useful for differentiating between high- and low-grade myxoid liposarcomas and can help in clinical decision making.

Smart branched polymer drug conjugates as nano-sized drug delivery systems.

Polymer-drug conjugates represent excellent nanopharmaceutical candidates, as they offer multiple advantages related to their intrinsic characteristics. Many of the said characteristics are provided by the covalent bonding between the drug and the polymer. However, their clinical development has been slow and only one polymer-drug conjugate has reached the market, thus there remains an urgent need for the development of new and smart polymeric systems. Desirable characteristics of these new systems include higher molecular weight and degree of homogeneity, predictable conformations in solution, multivalency, and increased drug loading capacity, amongst others. With these aims in mind, branched polymers are ideal candidates due to their unique rheological, mechanical, and biomedical properties derived from their structure, inaccessible for linear polymers. Within this review, the synthetic strategies developed and the main efforts towards branched polymer implementation as carriers for polymer-drug conjugates will be addressed.

Facial Video-Based Photoplethysmography to Detect HRV at Rest.

Our aim is to demonstrate the usefulness of photoplethysmography (PPG) for analyzing heart rate variability (HRV) using a standard 5-min test at rest with paced breathing, comparing the results with real RR intervals and testing supine and sitting positions. Simultaneous recordings of R-R intervals were conducted with a Polar system and a non-contact PPG, based on facial video recording on 20 individuals. Data analysis and editing were performed with individually designated software for each instrument. Agreement on HRV parameters was assessed with concordance correlations, effect size from ANOVA and Bland and Altman plots. For supine position, differences between video and Polar systems showed a small effect size in most HRV parameters. For sitting position, these differences showed a moderate effect size in most HRV parameters. A new procedure, based on the pixels that contained more heart beat information, is proposed for improving the signal-to-noise ratio in the PPG video signal. Results were acceptable in both positions but better in the supine position. Our approach could be relevant for applications that require monitoring of stress or cardio-respiratory health, such as effort/recuperation states in sports.

Multilayer Architectures for Facial Action Unit Recognition.

In expression recognition and many other computer vision applications, the recognition performance is greatly improved by adding a layer of nonlinear texture filters between the raw input pixels and the classifier. The function of this layer is typically known as feature extraction. Popular filter types for this layer are Gabor energy filters (GEFs) and local binary patterns (LBPs). Recent work [1] suggests that adding a second layer of nonlinear filters on top of the first layer may be beneficial. However, it is unclear what is the best architecture of layers and selection of filters. In this paper, we present a thorough empirical analysis of the performance of single-layer and dual-layer texture-based approaches for action unit recognition. For the single hidden layer case, GEFs perform consistently better than LBPs, which may be due to their robustness to jitter and illumination noise as well as to their ability to encode texture at multiple resolutions. For dual-layer case, we confirm that, while small, the benefit of adding this second layer is reliable and consistent across data sets. Interestingly for this second layer, LBPs appear to perform better than GEFs.

Hidrocele con calcificación masiva escrotal / Hydrocele with massive scrotal calcification

No disponible

Human and computer recognition of facial expressions of emotion.

Neuropsychological and neuroimaging evidence suggests that the human brain contains facial expression recognition detectors specialized for specific discrete emotions. However, some human behavioral data suggest that humans recognize expressions as similar and not discrete entities. This latter observation has been taken to indicate that internal representations of facial expressions may be best characterized as varying along continuous underlying dimensions. To examine the potential compatibility of these two views, the present study compared human and support vector machine (SVM) facial expression recognition performance. Separate SVMs were trained to develop fully automatic optimal recognition of one of six basic emotional expressions in real-time with no explicit training on expression similarity. Performance revealed high recognition accuracy for expression prototypes. Without explicit training of similarity detection, magnitude of activation across each emotion-specific SVM captured human judgments of expression similarity. This evidence suggests that combinations of expert classifiers from separate internal neural representations result in similarity judgments between expressions, supporting the appearance of a continuous underlying dimensionality. Further, these data suggest similarity in expression meaning is supported by superficial similarities in expression appearance.

Face recognition by independent component analysis.

A number of current face recognition algorithms use face representations found by unsupervised statistical methods. Typically these methods find a set of basis images and represent faces as a linear combination of those images. Principal component analysis (PCA) is a popular example of such methods. The basis images found by PCA depend only on pairwise relationships between pixels in the image database. In a task such as face recognition, in which important information may be contained in the high-order relationships among pixels, it seems reasonable to expect that better basis images may be found by methods sensitive to these high-order statistics. Independent component analysis (ICA), a generalization of PCA, is one such method. We used a version of ICA derived from the principle of optimal information transfer through sigmoidal neurons. ICA was performed on face images in the FERET database under two different architectures, one which treated the images as random variables and the pixels as outcomes, and a second which treated the pixels as random variables and the images as outcomes. The first architecture found spatially local basis images for the faces. The second architecture produced a factorial face code. Both ICA representations were superior to representations based on PCA for recognizing faces across days and changes in expression. A classifier that combined the two ICA representations gave the best performance.

The Morton-Massaro law of information integration: implications for models of perception.

Information integration may be studied by analyzing the effect of 2 or more sources (e.g., auditory and visual) on participants' responses. Experiments show that ratios of response probabilities often factorize into components selectively influenced by only 1 source (e.g., 1 component affected by the acoustic source and another 1 affected by the visual source). This is called the Morton-Massaro law (MML). This article identifies conditions in which the law is optimal and notes that it reflects an implicit assumption about the statistics of the environment. Adherence to the MML can be used to assess whether the assumption is being made, and analyses of natural stimuli can be used to determine whether the assumption is reasonable. Feed-forward and interactive models subject to a channel separability constraint are consistent with the law.

Collateral biliary circulation in portal hypertension syndrome.

OBJECTIVE: to describe collateral circulation in the gallbladder wall in relation with portal hypertension syndrome, and to determine whether this syndrome is frequently associated portal vein thrombosis. METHODS: images were retrospectively reviewed for 9 patients with previously diagnosed portal hypertension syndrome, in whom ultrasound results suggested the presence of varices of the cystic vein. RESULTS: four patients showed signs suggesting portal vein thrombosis. The gallbladder wall showed diffuse hypoechoic thickening in all patients, 7 of whom had intramural dilation of tubular, tortuous appearance. Ultrasound findings, however, were not very specific, and differential diagnosis with a large number of other entities is required to rule out other possible causes of focal and diffuse thickening of the gallbladder wall. The use of Doppler sonographic techniques made it possible to determine the cause of the varices, and to confirm suspicions of portal thrombosis. This method was found to be just as sensitive as ultrasound imaging, and much more specific. Angiograms obtained in 3 patients for different reasons confirmed the ultrasonographic findings in all cases. CONCLUSIONS: this study confirms the association between thromboses and varices, and analyzes the physiopathological hypotheses invoked to explain this association. We emphasize the need for correct diagnosis, given the frequency of surgical iatrogenic bleeding or misdiagnosis resulting from confusion with other possible causes of gallbladder wall thickening. Doppler ultrasound is considered the ideal diagnostic method as it is harmless, sensitive and specific.

[Morphometric study of somatostatin-producing "D" cells in duodenum and pancreas of the rat, following experimental antrectomy]. / Estudio morfométrico de las células "D" productoras de somatostatina en duodeno y páncreas de la rata, tras la antrectomía experimental.

Given the inhibition of gastric secretion by the "D" cells producing somatostatin in antral mucosa, as well as evidence of disorders of the postprandial blood glucose after antrectomy, we may expect as a result of the antral resection a series of modifications in the content of the "D" cells in duodenum and pancreas. The study group was made up of 30 Sprague-Dawley albino rats, distributed in 3 groups as follows: Billroth I, Billroth II and laparotomy. The "D" cell study and the morphometric analysis after immunohistochemical avidin-biotin, was carried out with an automatic image analyzer and a morphometric calculation program. The results show that: the "D" cell population decreased significantly in the B-II group while the number of pancreatic islets and the average insular surface, did not show significantly differences in the tree groups, the relationship of the average insular surface with respect to the pancreas, decreased significantly in the two groups with antrectomy, expressing a hyperplasia of the exocrine pancreas and that the number of insular "D" cells decreased significantly in the B-II group and didn't change in the B-I group. These findings suggest that antrectomy, originates an increase of the exocrine pancreas and that antrectomy with gastrojejunal anastomosis excluding the duodenum, decreases the number of duodenal "D" cells and number of "D" cells of the pancreatic islets.

[The effect of duodenal exclusion on the cellular endocrine adaptation of the duodenum after performing an antrectomy. An experimental study in the rat]. / Influencia de la exclusión duodenal en la adaptación celular endocrina del duodeno tras la práctica de una antrectomía. Estudio experimental en la rata.

We present an experimental study in rats with the aim to value the adaptative variations over the duodenal gastrin and somatostatin cell producing populations after antrectomy and gastrojejunostomy. 30 animals were distributed into two groups of 15 animals each. Group 1 rats underwent antrectomy and gastrojejunostomy, the animals of group 2 were considered as a controls. The results obtained show that after antrectomy and gastrojejunostomy an increase of gastrin producing cells is produced as well as decrease of somatostatin producing cells, both figures are statistically significant, concluding that the duodenum is able to supply the gastric antrum in gastrin production while the duodenal somatostatin cell producing population is negative influenced by the absence of alimentary stimuli and gastric secretions.

[Adaptive duodenal endocrine cell changes after antrectomy. Experimental study in the rat]. / Cambios celulares endocrinos duodenales adaptativos tras la práctica de una antrectomía. Estudio experimental en la rata.

The known gastric endocrine relationship between "G" cells and "D" cells is altered after the loss of antral "G" cell population after antrectomy, leading to physiologic adaptative changes over the cell population producing gastrin and somatostatin in the duodenum, replacing thus the endocrine function of the resected gastric antrum. In this experimental study, Sprague-Dawley rats have been randomized in two groups, Control and Antrectomy with gastroduodenostomy, maintaining the alimentary stimulation of the duodenum. Endocrine "G" and "D" cell studies have been carried out by immunohistochemical staining with an Avidin-Biotin affinity technique. The statistical method used was the "t" test of Student. The results demonstrated a significant increase of the duodenal "G" cell population without changes of the duodenal "D" cell population after antrectomy and gastroduodenostomy. The endocrine cell ratio "G/D" in the duodenum increases due to the loss of antral gastrin release and the decrease of gastric acid output provoked by antrectomy.