An Object-Oriented Framework for Robust Multivariate Analysis

Taking advantage of the S4 class system of the programming environment R, which facilitates the creation and maintenance of reusable and modular components, an object-oriented framework for robust multivariate analysis was developed. The framework resides in the packages robustbase and rrcov and includes an almost complete set of algorithms for computing robust multivariate location and scatter, various robust methods for principal component analysis as well as robust linear and quadratic discriminant analysis. The design of these methods follows common patterns which we call statistical design patterns in analogy to the design patterns widely used in software engineering. The application of the framework to data analysis as well as possible extensions by the development of new methods is demonstrated on examples which themselves are part of the package rrcov.

Hydatid liver disease - a review of the literature

Hydatid cyst disease of the liver is a worldwide parasitosis with significant debilitating effect on the patients. In Bulgaria, the most important biological reservoir and the final host is the dog. The distribution of the disease in the territory of the country is variable. Advances of laboratory and imaging diagnostic methods provide new options for multimodal approach. Surgery has been mainstay of treatment, however, new minimally invasive methods such as laparoscopic surgery and PAIR present with advantages in selected patients. Perioperative therapy diminishes postoperative relapses. In the present review, new data about the epidemiology and recent achievements in diagnosis and management of hydatid liver disease are presented.Scripta Scientifica Medica 2013; 45(2): 17-22

CLINICAL OUTCOME OF INTERSPHINCTERIC RESECTION FOR ULTRA-LOW RECTAL CANCER

BACKGROUND: Laparoscopic surgery has been reported to be one of the approaches for total mesorectal excision (TME) in rectal cancer surgery. Intersphincteric resection (ISR) has been reported as a promising method for sphincter-preserving operation in selected patients with very low rectal cancer. METHODS: We try to underline the important surgical issues surrounding the management of patients with low rectal cancer indicated to laparoscopic intersphincteric resection (ISR). From January 2007 till now, 35 patients with very low rectal cancer underwent laparoscopic TME with ISR. We report and analyze the results from them RESULTS: Conversion to open surgery was necessary in one (3%) patient. The median operation time was 293 min and median estimated blood loss was 40 ml. The pelvic plexus was completely preserved in 32 patients. There was no mortality. Postoperative complications occurred in three (9%) patients. The median length of postoperative hospital stay was 11 days. Macroscopic complete mesorectal excision was achieved in all cases. Complete resection (R0) was achieved in 21 (91%) patients.CONCLUSIONS: Laparoscopic TME with ISR is technically feasible and a safe alternative to laparotomy with favorable short-term postoperative outcomes. The literature research made by us found that the laparoscopic approach can be underwent in most patients with low rectal cancer in which laparoscopic ISR represents a feasible alternative to conventional open surgery

General approach to coordinate representation of compositional tables

This is the peer reviewed version which has been published in final form at [https://doi.org/10.1111/sjos.12326]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Compositional tables can be considered a continuous counterpart to the well-known contingency tables. Their cells, which generally contain positive real numbers rather than just counts, carry relative information about relationships between two factors. Hence, compositional tables can be seen as a generalization of (vector) compositional data. Due to their relative character, compositions are commonly expressed in orthonormal coordinates using a sequential binary partition prior to being further processed by standard statistical tools. Unfortunately, the resulting coordinates do not respect the two-dimensional nature of compositional tables. Information about relationship between factors is thus not well captured. The aim of this paper is to present a general system of orthonormal coordinates with respect to the Aitchison geometry, which allows for an analysis of the interactions between factors in a compositional table. This is achieved using logarithms of odds ratios, which are also widely used in the context of contingency tables

Association of SNPs in EGR3 and ARC with schizophrenia supports a biological pathway for schizophrenia risk

We have previously hypothesized a biological pathway of activity-dependent synaptic plasticity proteins that addresses the dual genetic and environmental contributions to schizophrenia. Accordingly, variations in the immediate early gene EGR3, and its target ARC, should influence schizophrenia susceptibility. We used a pooled Next-Generation Sequencing approach to identify variants across these genes in U.S. populations of European (EU) and African (AA) descent. Three EGR3 and one ARC SNP were selected and genotyped for validation, and three SNPs were tested for association in a replication cohort. In the EU group of 386 schizophrenia cases and 150 controls EGR3 SNP rs1877670 and ARC SNP rs35900184 showed significant associations (p = 0.0078 and p = 0.0275, respectively). In the AA group of 185 cases and 50 controls, only the ARC SNP revealed significant association (p = 0.0448). The ARC SNP did not show association in the Han Chinese (CH) population. However, combining the EU, AA, and CH groups revealed a highly significant association of ARC SNP rs35900184 (p = 2.353 x 10(-7); OR [95% CI] = 1.54 [1.310-1.820]). These findings support previously reported associations between EGR3 and schizophrenia. Moreover, this is the first report associating an ARC SNP with schizophrenia and supports recent large-scale GWAS findings implicating the ARC complex in schizophrenia risk. These results support the need for further investigation of the proposed pathway of environmentally responsive, synaptic plasticity-related, schizophrenia genes

Radiofrequency ablation of unresectable primary and metastatic hepatic malignancies

Отворената хирургия е златен стандарт за лечение на хепатоцелуларен карцином (НСС) и чернодробни метастази от рак на дебелото черво. Днес чернодробната резекция е все още само лечебен вариант за пациенти с рак на черния дроб, с 5-годишната преживяемост между 25-60%, в сравнение с 0% 5-годишна преживяемост без никакви лечение. Само 5-15% от пациентите с НСС или с чернодробни метастази могат да бъдат подложени на чернодробна резекция поради различни противопоказания: голям брой тумори, тумори на труднодостъпни места, недостатъчен чернодробен обем за резекция.Open surgery is a gold standard for treating hepatocellular carcinoma (HCC) and hepatic metastases of colorectal cancer. Today, liver resection is still only a radically option for patients with liver cancer, with a 5-year survival rate of 25-60%, compared with 0% 5-year survival without any treatment. Only 5-15% of patients with HCC or liver metastases may undergo hepatic resection due to different contraindications: a large number of tumors, tumors in hard-to-reach places, insufficient hepatic volume for resection

INFLUENCE OF THE FDG-PET/CT ON THE DIAGNOSE AND STAGING OF COLORECTAL CANCER.

INTRODUCTION: In patients with colorectal cancer (CRC), preoperative evaluation and staging should focus on techniques that might alter the preoperative or intraoperative surgical plan. Conventional imaging methods (CT, MRI) have low accuracy for identifying the depth of tumour infiltration and have limited ability to detect regional lymph node involvement. The aim of this study was to evaluate the utility of FDG-PET in the initial staging of patients with CC in comparison with conventional staging methods and to determine its impact on therapeutic management.METHODS: In First Clinic of Surgery at University Hospital “St. Marina” one hundred and four patients with a diagnosis of CRC (53 males and 51 females; mean age 66.76± 12.36 years), selected prospectively. All patients were studied for staging using a standard procedure (CT) and FDG-PET. The reference method was histology. The effect of FDG-PET on the diagnose and the operative treatment was studied.RESULTS: In 14 patients, surgery was contraindicated by FDG-PET owing to the extent of disease (only 6/14 suspected by CT). FDG-PET revealed four synchronous tumours. For N staging, both procedures showed a relatively high specificity but a low diagnostic accuracy (PET 56%, CT 60%) and sensitivity (PET 21%, CT 25%). For M assessment, diagnostic accuracy was 92% for FDGPET and 87% for CT. FDG-PET results led to modification of the therapy approach in 17.85% of the patients with rectal cancer and in 14.8% of the patients with colon cancer.CONCLUSION: Compared with conventional techniques, FDGPET appears to be useful in pre-surgical staging of CC, revealing unsuspected disease and impacting on the treatment approach

Minimally invasive ablative techniques of liver tumors

Само 5-15% от пациентите с НСС или с чернодробни метастази могат да бъдат подложени на чернодробна резекция, поради различни противопоказания: голям брой тумори, тумори на трудно достъпни места, недостатъчен чернодробен обем за резекция. Вариантите за перкутанно лечение могат да бъдат: Химичната аблация: инжектиране на етанол или оцетна киселина; Термалната аблация: (а) криохирургични аблация (CSA/КХА): използване на течен азот, аргон, или NO2; (б) коагулационната: използване на радиочестотен ток (RFA/РФА); Микровълнова аблация (MWA/МВ); лазерна интерстициална термотерапия (ЛИТТ) или високоинтензивен фокусиран ултразвук (HIFU/ ВФУ); Необратима електропорация (IRE).Only 5-15% of patients with HCC or liver metastases may undergo hepatic resection due to different contraindications: a large number of tumors, tumors in hard-to-reach places, insufficient hepatic volume for resection. The options for percutaneous treatment can be: Chemical Ablation: Injection of Ethanol or Acetic Acid; Thermal ablation: (a) cryosurgical ablation (CSA): use of liquid nitrogen, argon, or NO2; (b) Coagulation: Radio Frequency Ablation (RFA); Microwave ablation (MWA); Laser Interstitial Thermotherapy (LITT) or High Intensive Focused Ultrasound (HIFU); Irreversible electroporation (IRE)

26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)