Clinical Efficacy of SARS-CoV-2 Vaccination in Hemodialysis Patients.

Introduction: The COVID-19 pandemic is a global public health problem. Patients with end-stage renal disease on hemodialysis are at a higher risk of infection and mortality than the general population. Worldwide, a vaccination campaign has been developed that has been shown to reduce severe infections and deaths in the general population. However, there are currently limited data on the clinical efficacy of vaccinations in the hemodialysis population. Methods: A national multicenter observational cohort was performed in Chile to evaluate the clinical efficacy of anti-SARS-CoV-2 vaccination in end-stage renal disease patients on chronic hemodialysis from February 2021 to August 2021. In addition, the BNT162b2 (Pfizer-BioNTech) and CoronaVac (Sinovac) vaccines were evaluated. The efficacy of vaccination in preventing SARS-CoV-2 infection, hospitalizations, and deaths associated with COVID-19 was determined. Results: A total of 12,301 patients were evaluated; 10,615 (86.3%) received a complete vaccination (2 doses), 490 (4.0%) received incomplete vaccination, and 1196 (9.7%) were not vaccinated. During follow-up, 1362 (11.0%) patients developed COVID-19, and 150 died (case fatality rate: 11.0%). The efficacy of the complete vaccination in preventing infection was 18.1% (95% confidence interval [CI]:11.8-23.8%), and prevention of death was 66.0% (95% CI:60.6-70.7%). When comparing both vaccines, BNT162b2 and CoronaVac were effective in reducing infection and deaths associated with COVID-19. Nevertheless, the BNT162b2 vaccine had higher efficacy in preventing infection (42.6% vs. 15.0%) and deaths (90.4% vs. 64.8%) compared to CoronaVac. Conclusion: The results of our study suggest that vaccination against SARS-CoV-2 in patients on chronic hemodialysis was effective in preventing infection and death associated with COVID-19.

Survival study and factors associated with mortality in Chilean patients on peritoneal dialysis infected with SARS-CoV-2.

The Covid-19 pandemic has been responsible for millions of deaths worldwide. Patients with comorbidities- such as those on peritoneal dialysis (PD)- present higher morbidity and mortality than the general population. We prospectively evaluated all Chilean patients on PD (48 centres) and followed those who had Covid-19 from the beginning of the Covid-19 pandemic in Chile (March 2020) to January 2021 (start of vaccination campaign). We described demographic history, comorbidities, factors related to infection, need for hospitalisation and death due to Covid-19. During the study period, 106 adults on PD were infected by SARS-CoV-2, with a mean age of 53.1 (±16.3) and of which 53.9% were female. From that group, 54.8% required hospitalisation and 24.5% (n = 26) died due to Covid-19. Most of the patients (63.4%) were infected at home and 22.8% during hospitalisation for other reasons. There was a significant association for Covid-19 mortality with: being ≥60 years old, diabetes, time on PD ≥5 years, need for hospitalisation and hospital-acquired infection. At 90 days of follow-up, all deaths associated to Covid-19 occurred before 40 days. We conclude that patients on PD without Covid-19 vaccination have a high mortality and need for hospitalisation associated to Covid-19. To avoid this negative outcome, it is necessary to intensify strategies to avoid contagion, especially in those ≥60 years old, with diabetes and/or ≥5 years spent on PD.

Quadruple therapies are superior to standard triple therapy for Helicobacter pylori first-line eradication in Chile. / Terapias cuádruples son superiores a terapia triple estándar en primera línea de erradicación de Helicobacter pylori en Chile.

INTRODUCTION: Helicobacter pylori infection affects approximately 70% of the Chilean population. It is a public health problem whose eradication treatment is part of the explicit health guarantees in Chile. OBJECTIVES: Characterize the most widely used H. pylori first-line eradication therapies in our environment and evaluate their efficacy. METHODS: A retrospective observational study was carried out where, in patients with certified H. pylori infection, the eradication therapy indicated by the treating physician, its efficacy, adherence and adverse effects, in addition to the eradication certification method used, were evaluated. RESULTS: 242 patients and 4 main therapies were analyzed: standard triple therapy, dual therapy, concomitant therapy, and bismuth quadruple therapy. Eradication rates of 81.9% (95% CI 74.44-87.63), 88.5% (95% CI 73.13-95.67), 93.7% (95% CI 78.07-98.44) and 97.6% (95% CI 84.81-99.67) were observed respectively, with concomitant therapy (RR: 1.14; 95% CI 1.01-1.29; p=.028) and quadruple therapy with bismuth (RR: 1.19; 95% CI 1.09-1.31; p<.001) being significantly more effective than standard triple therapy. Regarding the rate of reported adverse effects, it was 58.5% (95% CI 50.66-65.92), 35.4% (95% CI 24.6-48.11), 22.9% (95% CI 81-37.14) and 63.4% (95% CI 47.8-76.64), having the dual and concomitant therapy significantly fewer adverse effects compared with standard therapy. CONCLUSIONS: Quadruple therapies are superior to standard triple therapy and should be considered as first-line treatment in Chile. Dual therapy is promising. More studies will be required to determine which therapies are most cost-effective.

Consenso chileno de diagnóstico y manejo de neoplasias quísticas pancreáticas. Club de páncreas Chile-SCHGE / Chilean consensus on diagnosis and management of pancreatic cystic neoplasms

Pancreatic cystic neoplasms (PCN) are frequently detected on abdominal images performed for non-pancreatic indications. Their prevalence in asymptomatic population ranges from 2.7 to 24.8%, and increases with age. There are several types of pancreatic cysts. Some may contain cancer or have malignant potential, such as mucinous cystic neoplasms, including mucinous cystadenoma (MCN) and intraductal papillary mucinous neoplasms (IPMN). In contrast, others are benign, such as serous cystadenoma (SCA). However, even those cysts with malignant potential rarely progress to cancer. Currently, the only treatment for pancreatic cysts is surgery, which is associated with high morbidity and occasional mortality. The Board of the Chilean Pancreas Club of the Chilean Gastroenterology Society developed the first Chilean multidisciplinary consensus for diagnosis, management, and surveillance of PCN. Thirty experts were invited and answered 21 statements with five possible alternatives: 1) fully agree; 2) partially agree; 3) undecided; 4) disagree and 5) strongly disagree. A consensus was adopted when at least 80% of the sum of the answers "fully agree" and "partially agree" was reached. The consensus was approved by the Board of Directors of the Chilean Pancreas Club for publication.

[Chilean consensus on diagnosis and management of pancreatic cystic neoplasms]. / Consenso chileno de diagnóstico y manejo de neoplasias quísticas pancreáticas. Club de páncreas Chile-SCHGE.

Pancreatic cystic neoplasms (PCN) are frequently detected on abdominal images performed for non-pancreatic indications. Their prevalence in asymptomatic population ranges from 2.7 to 24.8%, and increases with age. There are several types of pancreatic cysts. Some may contain cancer or have malignant potential, such as mucinous cystic neoplasms, including mucinous cystadenoma (MCN) and intraductal papillary mucinous neoplasms (IPMN). In contrast, others are benign, such as serous cystadenoma (SCA). However, even those cysts with malignant potential rarely progress to cancer. Currently, the only treatment for pancreatic cysts is surgery, which is associated with high morbidity and occasional mortality. The Board of the Chilean Pancreas Club of the Chilean Gastroenterology Society developed the first Chilean multidisciplinary consensus for diagnosis, management, and surveillance of PCN. Thirty experts were invited and answered 21 statements with five possible alternatives: 1) fully agree; 2) partially agree; 3) undecided; 4) disagree and 5) strongly disagree. A consensus was adopted when at least 80% of the sum of the answers "fully agree" and "partially agree" was reached. The consensus was approved by the Board of Directors of the Chilean Pancreas Club for publication.

Polymeric nanoencapsulation of alpha interferon increases drug bioavailability and induces a sustained antiviral response in vivo.

Polymeric nanoparticulate systems allow the encapsulation of bio-active substances, giving them protection against external agents and increasing the drug's bioavailability. The use of biocompatible and biodegradable polymers usually guarantees the harmless character of the formulation, and a controlled drug release is also assured. A relatively easy procedure to obtain polymeric formulations of bioactive agents is ionotropic gelation, which allows the synthesis of chitosan (CS) - sodium tri-polyphosphate nanoparticles (NPs) loading encapsulated proteins. In this work, Bovine serum albumin (BSA) model protein and a recombinant porcine alpha interferon variant were used to obtain nanoparticulate formulations. The internalization of the encapsulated material by cells was studied using a BSA-fluorescein system; the fluorescent conjugate was observable inside the cells after 20 h of incubation. The therapeutic CS-alpha interferon formulation showed a maximum of protein released in vitro at around 90 h. This system was found to be safe in a cytotoxicity assay, while biological activity experiments in vitro showed antiviral protection of cells in the presence of encapsulated porcine alpha interferon. In vivo experiments in pigs revealed a significant and sustained antiviral response through overexpression of the antiviral markers OAS2 and PKR. This proves the preservation of porcine alpha interferon biological activity, and also that a lasting response was obtained. This procedure is an effective and safe method to formulate drugs in nanoparticulate systems, representing a significant contribution to the search for more effective drug delivery strategies.

Variations in periplasmic loop interactions determine the pH-dependent activity of the hexameric urea transporter UreI from Helicobacter pylori: a molecular dynamics study.

BACKGROUND: Helicobacter pylori is an important factor in the development of diseases such as ulcer and gastric cancer. This bacterium uses a periplasmic transporter, UreI, to deliver urea to the intracelullar space, where later it is transformed into ammonia by the cytoplasmic enzyme urease to survive the acidic condition of the human stomach. The UreI transporter presents a pH-dependent activity, where this pH-dependence remains unknown at a structural level. Althought the existance of several protonable residues in the periplasmic loops are related to the pH-dependent activity, we find interesting to have a clear view of the conformational changes involved in this phenomena through a molecular dynamic study. RESULTS: Molecular dynamic simulations of the UreI transporter at three different pH conditions were performed, revealing two main pH-dependent conformations, which we present as the open and close states. We find that salt bridges between the periplasmic loops are crucial interactions that stabilize these conformations. Besides, a cooperative behaviour exists between the six subunits of the system that is necessary to fulfill the activity of this transporter. CONCLUSIONS: We found different pH-dependent conformations of the urea transporter UreI from Helicobacter pylori, which are related to salt-bridge interactions in the periplasmic regions. The behaviour of every channel in the system is not independent, given the existance of a cooperative behaviour through the formation of salt-bridges between the subunits of the hexameric system. We believe that our results will be related to the generation of new eradication therapies using this transporter as an attractive target, denoting that the knowledge of the possible pH-dependent conformations adopted for this transporter are important for the development of rational drug design approximations.