Melatonin receptor antagonists that differentiate between the human Mel1a and Mel1b recombinant subtypes are used to assess the pharmacological profile of the rabbit retina ML1 presynaptic heteroreceptor

We have identified subtype selective agonists, partial agonists and antagonists, which distinguish the human recombinant Mel1a and Mel1b melatonin receptors expressed in COS-7 cells. Melatonin receptor agonists showed higher affinity for competition of 2-[125I]-iodomelatonin binding for the Mel1b than the Mel1a melatonin receptor. The dissociation constants (Ki) of 16 agonists determined on the recombinant human Mel1a and Mel1b melatonin receptor subtypes showed a significant correlation (r2 = 0.85, slope = 0.97, P < 0.0001, n = 16). However, six agonists showed 10 to 60 fold higher affinity for the Mel1b melatonin receptor as indicated by the affinity selectivity ratios (Mel1a/Mel1b) [8-methoxy-2-acetamidotetraline (11); S20098 (14); 8-methoxy-2-propionamidotetraline (20); 6, 7 di-chloro-2-methylmelatonin (21); 6-chloromelatonin (57); 6-methoxymelatonin (59)]. Dissociation constants for competition of 11 partial agonists and antagonist for 2-[125I]-iodomelatonin binding were between 15.5 (luzindole, pKi: 7.7) to 362 (4-phenyl-2-chloroacetamidotetraline, pKi: 9.1) fold higher for the Mel1b than for the Mel1a melatonin receptor. The lack of correlation between the pKi values (r2 = 0.23, P > 0.1, n = 11) strongly suggest that the two human melatonin receptor subtypes can be distinguished pharmacologically. The partial agonist: 5-methoxyluzindole (pKi: 9.6) and the competitive melatonin receptor antagonists: GR128107 (pKi: 9.6), 4-phenyl-2-chloroacetamidotetraline (pKi: 9.1), 4-phenyl-2-acetamidotetraline (pKi: 8.9) and 4-phenyl-2-propionamidotetraline (pKi: 8.8) are selective Mel1b melatonin receptor analogues as their affinity selectivity ratios (Mel1a/Mel1b) are bigger than 100. We conclude that the 40% overall amino acid difference in the sequence of the human recombinant Mel1a and Mel1b melatonin receptors is reflected in distinct pharmacological profiles for the subtypes. We compared the pharmacological profile of the presynaptic ML1 melatonin heteroreceptor of rabbit retina mediating inhibition of the calcium-dependent release of dopamine to that of the recombinant Mel1a and Mel1b melatonin receptors. Melatonin inhibited [3H]dopamine release by 50% (1C50) at 20 pM with a maximal inhibitory effect (80%) at 1 nM. The partial agonists, i.e., N-acetyltryptamine (1C50 5.6, maximal inhibition 55%) and 5-methoxyluzindole (1C50: 1.3, maximal inhibition 40%) showed various degrees of efficacy while none of the competitive melatonin receptor antagonists did inhibit [3H]dopamine release on their own. The potency (1C50) of full melatonin receptor agonists significantly correlated with their affinity to compete for 2-[125I]-iodomelatonin binding to either the Mel1a (r2 = 0.76, slope = 0.77, P < 0.0001, n = 17) or Mel1b (r2 = 0.63, slope = 0.75, P < 0.001, n = 17) human melatonin receptors. By contrast, the apparent dissociation constants (KB) for partial agonists and antagonists to antagonize the inhibition of [3H]dopamine release mediated by activation of the ML1 heteroreceptor by melatonin, significantly correlated with the affinity constants (Ki) for 2-[125I]-iodomelatonin binding determined of the Mel1b (r2 = 0.77, slope = 0.55, P < 0.001; n = 11) but not the Mel1a (r2 = 0.27, P < 0.1, n = 11) subtype. Together these results demonstrate that the pharmacological profile of the human recombinant Mel1b melatonin receptor is similar to that of the functional presynaptic melatonin heteroreceptor of rabbit retina, which we referred as an ML1B subtype. We conclude that the selective Mel1b melatonin partial agonists and antagonists described here can be used to identify melatonin receptor subtypes in native tissues and to search for subtype selective analogues with therapeutic potential.

Quantification of serum markers of hepatitis B (HBV) and Delta virus (HDV) infections in patients with chronic HDV infection

The interplay between hepatitis B (HBV) and delta (HDV) viruses is complex and not always characterized during chronic HDV infection. We assessed the clinical usefulness of new quantitative assays for HBV and HDV serum markers in a retrospective cross-sectional study. Sera obtained from 122 HDV genotype 1 and HBV genotype D coinfected, anti-HIV-negative patients (71 males; median age 49.8 [21.7-66.9] years), recruited consecutively in two geographical areas (Italy 69 patients, Romania 53 patients) with different HBV and HDV epidemiology, were tested for HBsAg, HBV-DNA, HBcrAg, total anti-HBc, HDV-RNA, IgM and total anti-HDV using quantitative assays. Cirrhosis, which showed comparable prevalence in the two cohorts, was diagnosed in 97 of 122 (79.5%) patients. At multivariate analysis, cirrhosis was associated with lower total anti-HBc/IgM anti-HDV ratio (OR 0.990, 95% CI 0.981-0.999, P = .038), whereas disease activity was associated with higher total anti-HDV (OR 10.105, 95% CI 1.671-61.107, P = .012) and HDV-RNA levels (OR 2.366, 95% CI 1.456-3.844, P = .001). HDV-RNA serum levels showed a positive correlation with HBV-DNA (ρ = 0.276, P = .005), HBsAg (ρ = 0.404, P < .001) and HBcrAg (ρ = 0.332, P < .001). The combined quantitative profiling of HBV and HDV serum markers identifies specific patterns associated with activity and stage of chronic hepatitis D (CHD). HDV pathogenicity depends on the underlying active HBV infection in spite of the inhibition of its replication. HDV-RNA, IgM anti-HDV, total anti-HDV, total anti-HBc, HBsAg and HBcrAg serum levels qualify for prospective studies to predict progressive CHD and identify candidates to antiviral therapy.

Predictors of death on the waiting list for liver transplantation characterized by a long waiting time

The number of patients dying while on the liver transplantation (LT) waiting list (WL) has continued to increase in recent years as a result of severe shortage of organs. Therefore, it is important to evaluate the existing models that predict death on the WL and to determine the independent predictors of death. The study cohort comprised 152 adult patients listed for LT in our centre over a period of 2 years (January 2001 to January 2003). The 12-month survival rate has been calculated by Kaplan-Meier method. The survival analysis performed by Cox proportional hazard model has evaluated the three parameters which compose the model for end-stage liver disease (MELD) score. Forty-four patients (28.9%) died while listed for LT. The survival rate was 92% at 3 months, 80% at 6 months and 69% at 12 months. Median survival was not reached. MELD score was found to be an excellent predictor of death at 12 months on our WL--c-statistic (area under curve) 0.84. In our survival analysis, only international normalized (prothrombin) ratio (INR) and serum creatinine were identified as an independent predictors of death (P < 0.0001). A new simplified version of the MELD score, which does not include serum bilirubin, is proposed and its c-statistic as predictor for death on the WL at 12 months is 0.86, as good as the original MELD score, when evaluated on our list. There is a fourfold increase in mortality on our WL for LT between 3 and 12 months after the inclusion. A simplified version of the MELD score, using only serum creatinine and INR might be taken into account when predicting 12 months mortality on WL with longer waiting time, but it has to be confirmed by other prospective studies.

Characterization of hydrazine-stimulated proteolysis in human erythrocytes

The ability of hydrazine, acetylphenylhydrazine, methylhydrazine, and phenylhydrazine to stimulate proteolysis in red cells has been characterized. All four hydrazines effectively stimulated proteolysis in red cells and in hemolysate as evidenced by a two- to threefold increase in the rate of tyrosine release. The rate of tyrosine release varied linearly with time, increased with increasing concentration of hydrazine, and also increased as a function of hematocrit. The rank order for stimulation of proteolysis in red cells was phenylhydrazine greater than methylhydrazine greater than hydrazine approximately equal to acetylphenylhydrazine. Inhibitors of glycolysis in red cells only minimally (13-27%) decreased the rate of tyrosine release stimulated by the different hydrazines. Agents which diminished electron transport decreased the rate of tyrosine release. NADP inhibited the rate of tyrosine release stimulated by hydrazine, methylhydrazine, and acetylphenylhydrazine by approximately 36 to 41%; 2'-AMP was less effective. The rate of tyrosine release resulting from insult by the hydrazines was increased slightly by methylene blue, moderately inhibited (approximately 10 to 27%) by the chelator o-phenanthroline and inhibited approximately 30 to 40% by N-ethylmaleimide. Use of an oxygen-depleted atmosphere (N2) increased slightly the rate of tyrosine release stimulated by the hydrazines; in contrast, carbon monoxide decreased proteolysis stimulated by hydrazine, methylhydrazine, and acetylphenylhydrazine by approximately 50%. Although the antioxidants dimethylfuran, dimethylthiourea, and methylsulfoxide failed to diminish proteolysis stimulated by the hydrazines, N-acetylcysteine exerted a protective effect, decreasing hydrazine-stimulated tyrosine release in red cells approximately 30 to 50%. Inclusion of 3-amino-1,2,4-triazole in the incubation failed to increase further the rate of hydrazine-stimulated proteolysis. These data suggest that more reactive free radicals generated from the hydrazine are responsible for protein damage, that damaged protein (hemoglobin) is degraded via proteolysis, and that an ATP-independent process primarily participates in the degradation of abnormal proteins in the red cell. Thus, proteolytic enzymes present in the erythrocyte appear to exert a protective effect against cellular damage through the removal of abnormal proteins generated as a consequence of xenobiotic insult. The ability of proteolytic enzymes to recognize and degrade abnormal proteins may be of importance in using protein (hemoglobin)-xenobiotic adducts to assess exposure to toxic agents (risk assessment).

Collapse of the N=28 shell closure in (42)Si

The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from the fragmentation of secondary beams of (42,44)S at 39A MeV. The low 2(+) energy of (42)Si, 770(19) keV, together with the level schemes of (41,43)P, provides evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that (42)Si is best described as a well-deformed oblate rotor.

Impact of Quilting Sutures on Surgical Outcomes After Mastectomy: A Systematic Review and Meta-Analysis

BACKGROUND

Seroma after mastectomy and/or axillary lymph node dissection (ALND) is among the most common issue surgeons have to face in the early postoperative management of breast cancer. Using quilting sutures (QS) to aid in tissue approximation and decrease dead space is proposed as a simple technique to reduce seroma rate. We aimed to perform a systematic review, and analyse, in a meta-analytical model, the role of QS in improving wound outcomes and decrease volume, duration of drainage, and length of stay in hospital.

METHODS

The study was registered with PROSPERO. A systematic search of the PubMed, EMBASE, and SCOPUS databases was performed for all comparative studies examining surgical outcomes in patients who underwent QS versus conventional closure (CC) after mastectomy ± ALND.

RESULTS

Twenty-one studies with a total of 3473 patients (1736 in the study group and 1737 in the control group) were included based on the selection criteria. The study group showed significantly lower rates of seroma (p < 0.00001), total volume of drainage (p < 0.0001), days to drain removal (p < 0.00001), and length of stay (p < 0.00001) compared with the control group, while wound complication rates (surgical site infection, flap necrosis, hematoma, skin dimpling) were comparable between the two groups.

CONCLUSIONS

QS are a reliable intraoperative technique that decrease seroma formation, volume of postoperative drainage, duration of drainage and length of hospital stay, and should be considered in mastectomies with or without ALND.

Factors That May Enhance Longevity: A Literature Review and a Comprehensive Update for Aesthetic Surgeons

INTRODUCTION

After surgery, the plastic surgeon is very often questioned about how to maintain the result and more frequently how to slow down the aging process. However, this type of knowledge is not commonly delivered during medical education or at least needs an update. This review could be used as a guide to help plastic surgeons to manage these frequent postoperative consultations. The aim of this literature review was to focus discussion on specific positive factors, identified to have a significant impact on human longevity.

MATERIALS AND METHODS

A literature review was performed using the automated computerized PubMed search, with the keywords "human longevity." Only papers written in the English language were included. References were screened to identify further relevant articles. Experimental studies based on microorganisms and animals, works published in non-indexed journals, case reports, letters, and viewpoints were excluded.

RESULTS

One hundred and twenty-four articles reporting factors influencing human longevity were analyzed for data extraction. A total of 59 articles reporting only positive factors were included. Fourteen factors seemed to have a positive impact on longevity: caloric restriction, active effort and sports, happiness, vitamins, vegetarian or Mediterranean diet, oriental practices, socioeconomic status, genetics, sexual activity, sleep, moderate wine consumption, religion, and education.

CONCLUSION

While some factors with a positive impact on longevity are clearly identified and should be integrated in the postoperative process, further studies are still needed to be able to slow down the aging process.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

BACKGROUND

Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks.

METHODS

The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned.

RESULTS

A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31).

CONCLUSION

Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov).

Ribavirin with either standard or pegylated interferon to treat recurrent hepatitis C after liver transplantation

AIM

To investigate the efficacy of two anti-viral protocols in hepatitis C virus-reinfected liver transplant recipients.

METHODS

In this prospective study, 26 liver transplant patients were treated with standard interferon-alpha2b for 12 months or standard interferon-alpha2b for 3 months followed by pegylated interferon-alpha2b for 9 months. Interferon was combined with ribavirin in all patients. The histological course of the study population was compared with an untreated historic control group (n = 38) with similar baseline characteristics.

RESULTS

The sustained virological response rates in the standard interferon group and in the pegylated interferon group were 27.3% and 26.7%, respectively. Only 29% of patients with sustained virological response had end of treatment histological response, whereas 47% of viral non-responders showed end of treatment histological response. The percentage of patients with histological improvement was significantly higher in the study population when compared to the controls. Univariate analysis indicated that hepatitis C virus genotype non-1, high baseline alanine aminotransferase, the time interval between liver transplant and interferon therapy and the body mass index predicted sustained virological response. In the multivariate model, baseline alanine aminotransferase and the body mass index remained a significant predictor of sustained virological response.

CONCLUSIONS

Both treatment regimens offer similar efficacy profiles. Failure to eradicate hepatitis C virus should not lead to treatment discontinuation if serial liver biopsies demonstrate histological response.

[Immunologic research in pediatrics]

The child, in his ontogenesis, repeats the phylogenetic evolution of the immune processes. The immunologic maturation gradually appears, the process having a definite duration. The immunologic maturation seems to be parallel to the maturation of other physiological processes. The immune system of the child is different from that of the adult, and the development features of his immune reactivity will give a specific evolution to his morbid manifestations.

Memory-Non-Linearity Trade-Off in Distance-Based Delay Networks

The performance of echo state networks (ESNs) in temporal pattern learning tasks depends both on their memory capacity (MC) and their non-linear processing. It has been shown that linear memory capacity is maximized when ESN neurons have linear activation, and that a trade-off between non-linearity and linear memory capacity is required for temporal pattern learning tasks. The more recent distance-based delay networks (DDNs) have shown improved memory capacity over ESNs in several benchmark temporal pattern learning tasks. However, it has not thus far been studied whether this increased memory capacity comes at the cost of reduced non-linear processing. In this paper, we advance the hypothesis that DDNs in fact achieve a better trade-off between linear MC and non-linearity than ESNs, by showing that DDNs can have strong non-linearity with large memory spans. We tested this hypothesis using the NARMA-30 task and the bitwise delayed XOR task, two commonly used reservoir benchmark tasks that require a high degree of both non-linearity and memory.

Nutritional risk screening and prevalence of malnutrition on admission to gastroenterology departments: a multicentric study

BACKGROUND AND AIMS

There is little awareness and a lack of data on the prevalence of hospital malnutrition in gastro-enterology departments. Since part of these patients are referred for surgical treatment and poor nutritional status is a known risk factor for perioperative morbidity, we conducted a prospective study aimed to screen for the nutritional risk and assess the prevalence and risk factors of malnutrition in gastro-enterology departments in Romania.

METHODS

We included patients consecutively admitted to 8 gastroenterology units over a period of three months in our study. Nutritional risk was evaluated using NRS 2002. Malnutrition was defined using BMI ( 20 kg m2) or and 10% weight loss in the last six months.

RESULTS

3198 patients were evaluated, 51.6% males and 48.4% females, with the mean age of 54.5 Â+- 14.3 years. Overall percentage of patients at nutritional risk was 17.1%, with the highest risk for patients with advanced liver diseases (49.8%), oncologic (31.3%), inflammatory bowel diseases (20.2%), and pancreatic diseases (18.9%). The overall prevalence of malnutrition was of 20.4%, higher for advanced liver diseases (39.4%), inflammatory bowed diseases (30.6%), oncologic (26.8%) and pancreatic diseases (23%). Independent risk factors for malnutrition were younger age (p 0.0001), female gender (p 0.0001), a higher (A ≥ 3) NRS (p 0.0001), presence of neoplasm (p 0.0001), of advanced liver disease (p=0.0003) and a reduction of 25% of dietary intake (p 0.0001).

CONCLUSIONS

One in five patients admitted to gastroenterology units could benefit from prompt nutritional intervention. Correction of nutritional status is mandatory before any surgical procedure. Emphasis on nutritional evaluation at admission and beginning of nutritional therapy where needed are particularly required in patients with advanced liver diseases, digestive neoplasms, inflammatory bowel diseases and pancreatic diseases.

ABBREVIATIONS

NRS= nutritional risk score, BMI = body mass index, IBD = inflammatory bowel diseases.

MELD exceptions and new predictive score of death on long waiting lists for liver transplantation

BACKGROUND

Cirrhosis related complications, considered MELD exceptions, proved to add prognostic value to the MELD score in predicting waiting list mortality.

AIM

To identify the predictive value for death on a long waiting list (WL) for the complications of liver disease.

METHODS

During 2004-2007, 372 consecutive adult patients were listed for liver transplantation (LT). To identify the potential predictors of patient death, univariate and multivariate Cox's proportional hazards regression model was used.

RESULTS

In the univariate survival analysis the following variables were significant: spontaneous bacterial peritonitis, refractory ascites, hyponatremia, hepatic encephalopathy, hepatorenal syndrome, initial and current MELD score, initial and current Child-Pugh score. The independent predictors of death on our WL were: refractory ascites (p=0.002) and hepatorenal syndrome (p=0.002). Based on a logistic regression analysis a new score has been developed: Score = 1/(1+ exp(-(-4.38 + 1.34 x Refractory ascites + 0.9 x Hepatorenal syndrome + 0.15 x Current MELD). The c-statistic for the new score for prediction of death on the WL was 0.85 compared to 0.80 for current MELD score.

CONCLUSION

Refractory ascites and hepatorenal syndrome should add valuable points to the current MELD in order to better prioritize for LT patients included on long WL.

ABBREVIATIONS

Liver transplantation (LT), Model for End-Stage Liver Disease (MELD), waiting list (WL), United Network for Organ Sharing (UNOS), standard deviation (SD), receiver operating characteristic (ROC), hepatitis B virus (HBV), hepatocellular carcinoma (HCC), positive predictive value (PPV), negative predictive value (NPV), Child-Turcotte-Pugh (CTP), hepatic venous pressure gradient (HVPG).

Outcome of liver transplantation for hepatocellular carcinoma -- a single center experience

BACKGROUND & AIMS

Liver transplantation (LT) is a promising treatment for patients with liver cirrhosis associated with hepatocellular carcinoma (HCC). The aim of our study was to evaluate our experience regarding the clinical and pathological staging of HCC in patients who underwent LT, as well as recurrence free and overall survival.

METHODS

From January 2006 to December 2011, 38 patients with diagnosis of HCC, underwent LT in our Center. Demographic, clinical, imaging and pathologic information were recorded. A Cox proportional hazards survival analysis was performed in order to identify significant predictors of tumor recurrence and patient's death after LT.

RESULTS

Eighteen patients (47.4%) in our study group were within Milan criteria. The mean follow-up was 22 months and the recurrence rate of HCC after LT was 13.2%. The 1, 3- year recurrence free survival rates were 85%, 74.3% respectively. The 1 and 3-year overall survival rates were 83.5% and 63.6% respectively. No significant predictor for HCC recurrence was identified in our study group by survival analysis, taking into account 13 different variables. As independent predictors of patient'ss death after LT for HCC however, the presence of diabetes mellitus (p=0.001), presence of more than 3 HCC nodules (p=0.03) and tumor recurrence after LT (p=0.03) were identified by multivariate Cox proportional hazards survival analysis.

CONCLUSION

In our cohort HCC recurrence rate after LT was 13.2%. Diabetes mellitus, presence of more than 3 HCC nodules and HCC recurrence were significant predictors of poor overall survival after LT.

Evaluation of Changes in Circulating Cell-Free DNA as an Early Predictor of Response to Chemoradiation in Rectal Cancer-A Pilot Study

Background and Objectives: The objective of this study was to investigate quantitative changes in cell-free DNA (cfDNA) found in the bloodstream of patients with locally advanced rectal cancer who received neoadjuvant long-course chemoradiation, assuming a change in DNA fragments release during therapeutic stress. Materials and Methods: This was a prospective observational study that involved 49 patients who had three distinct pathologies requiring neoadjuvant chemoradiation: 18 patients with breast cancer, 18 patients with cervical cancer, and 13 patients with rectal cancer. Both breast cancer and cervical cancer patients were used as a control groups. Breast cancer patients were used as a control group as irradiation targeted healthy tissue after the tumor resection (R0), while cervical cancer patients were used as a control group to evaluate the effect of chemoradiation regarding cfDNA in a different setting (squamous cell carcinomas) and a different tumor burden. Rectal cancer patients were the study group, and were prospectively evaluated for a correlation between fragmentation of cfDNA and late response to chemoradiation. Blood samples were collected before the initiation of treatment and after the fifth radiation dose delivery. cfDNA was quantified in peripheral blood and compared with the patients' clinicopathological characteristics and tumor volume. Conclusion: Thirteen patients with locally advanced rectal cancer (T3/T4/N+/M0) were included in the study, and all of them had their samples analyzed. Eight were male (61.54%) and five were female (38.46%), with an average age of 70.85 years. Most of the patients had cT3 (53.85%) or cT4 (46.15%) tumors, and 92.31% had positive lymph nodes (N2-3). Of the thirteen patients, only six underwent surgery, and one of them achieved a pathological complete response (pCR). The mean size of the tumor was 122.60 mm3 [35.33-662.60 mm3]. No significant correlation was found between cfDNA, tumor volume, and tumor regression grade. cfDNA does not seem to predict response to neoadjuvant chemoradiotherapy and it is not correlated to tumor volume or tumor regression grade.

Assessment of Minimal Hepatic Encephalopathy with Brain MRI and EncephalApp Stroop Test

Background: Minimal hepatic encephalopathy (MHE) consists of subtle cognitive deficits that are not apparent on a standard neurological examination. Minimal hepatic encephalopathy has been reported in up to 80% of cirrhotic patients and is associated with decreased job performance, poor driving performance, impaired quality of life, and poor survival. In parallel, brain magnetic resonance imaging (MRI) abnormalities are known to occur in liver cirrhotic patients in the form of T1 globus pallidus hyperintensities. In recent years, a new psychometric test for diagnosing MHE has been developed as an app for smartphones and tablets (EncephalApp Stroop test). A translated version of the app is available in Romanian language. Aim:To use EncephalApp Stroop test for MHE diagnosis in our cirrhotic patients; to describe the main brain MRI abnormalities encountered in these patients; and to establish if Stroop test results correlate with imaging findings, clinical neurologic findings, and liver function parameters or prognosis. Material and methods:Cross-sectional study over a one-year period, involving 30 adult patients with liver cirrhosis. Subjects were evaluated through a standard neurological examination, psychometric testing using EncephalApp Stroop test, electroencephalogram and brain MRI. In parallel, 40 adult healthy controls were also recruited and evaluated with the EncephalApp Stroop test using the same methodology. Results:Age distribution was similar between the two groups (p=0.6). The mean age of patients was 50±10 years and that of controls 51±12 years. Mean Stroop result was 171±26 seconds for the patient group and 143±20 seconds for the control group (p<0.0001). There was a direct correlation between Stroop test results and age in the control group (R=0.69, p<0.0001) but not also in the patient group (R=0.28, p=0.13). Statistically significant results were obtained by using the Fischer exact test for both cut-off values: 145 seconds in patients < 45-year-old (p<0.001) and 190 seconds in those ≥45 years-old (p=0.03). MRI T1-hyperintensities of the basal ganglia, blood ammonia levels and electroencephalographic changes were not associated with poorer results. Conclusion:Our pilot study, although small, confirmed that patients with liver cirrhosis may have subtle deficits in cognitive areas like attention, concentration or reaction time. This can be assessed easily with the EncephalApp Stroop test which is readily available for use on smartphones or tablets.

Stem cells therapies for gastrointestinal and liver diseases

Stem cells therapies represent a new field of biomedical science which could provide in the future the cure for diseases until now incurable. The present paper reviews current knowledge on key biological properties of stem cells with focus on hepatic and gastrointestinal stem cells and current applications of stem cells therapies in gastrointestinal and liver diseases. Potential clinical applications for stem cells therapies have been suggested from animal model trials in acute liver failure, inherited metabolic liver disease and endstage liver disease (cirrhosis). Hematopoietic autologous stem cells transplantation has already been successfully performed in patients with severe inflammatory bowel disease or patients with refractory celiac disease with aberrant T cells. Future stem cells therapies for gastrointestinal postoperative or Crohn's disease fistulas are currently under investigation. More research is needed for perfecting stem cells harvesting protocols from different sources, in vitro expansion and differentiation protocols which can be used in phase II and III clinical trials.

Exploiting Signal Propagation Delays to Match Task Memory Requirements in Reservoir Computing

Recurrent neural networks (RNNs) transmit information over time through recurrent connections. In contrast, biological neural networks use many other temporal processing mechanisms. One of these mechanisms is the inter-neuron delays caused by varying axon properties. Recently, this feature was implemented in echo state networks (ESNs), a type of RNN, by assigning spatial locations to neurons and introducing distance-dependent inter-neuron delays. These delays were shown to significantly improve ESN task performance. However, thus far, it is still unclear why distance-based delay networks (DDNs) perform better than ESNs. In this paper, we show that by optimizing inter-node delays, the memory capacity of the network matches the memory requirements of the task. As such, networks concentrate their memory capabilities to the points in the past which contain the most information for the task at hand. Moreover, we show that DDNs have a greater total linear memory capacity, with the same amount of non-linear processing power.