Neurohormonal modulation: The new paradigm of pharmacological treatment of heart failure

The current paradigm of medical therapy for heart failure with reduced ejection fraction (HFrEF) is triple neurohormonal blockade with an angiotensin-converting enzyme inhibitor (ACEI), a beta-blocker (BB) and a mineralocorticoid receptor antagonist (MRA). However, three-year mortality remains over 30%. Stimulation of counter-regulatory systems in addition to neurohormonal blockade constitutes a new paradigm, termed neurohormonal modulation. Sacubitril/valsartan is the first element of this new strategy. PARADIGM-HF was the largest randomized clinical trial conducted in HFrEF. It included 8442 patients and compared the efficacy and safety of sacubitril/valsartan versus enalapril. The primary endpoint was the composite of cardiovascular mortality and hospitalization due to HF, which occurred in 914 (21.8%) patients receiving sacubitril/valsartan and in 1117 (26.5%) patients receiving enalapril (HR 0.8, 95% CI 0.73-0.87, p=0.0000002; NNT 21). Sacubitril/valsartan reduced both primary endpoint components, as well as sudden cardiac death, death due to worsening HF, and death from all causes. Patients on sacubitril/valsartan reported less frequent deterioration of HF and of quality of life, and discontinued study medication less frequently because of an adverse event. PARADIGM-HF demonstrated the superiority of sacubitril/valsartan over enalapril, with a 20% greater impact on cardiovascular mortality compared to ACEIs. Accordingly, in 2016, the European (ESC) and American (ACC/AHA/HFSA) cardiology societies simultaneously issued a class I recommendation for the replacement of ACEIs by sacubitril/valsartan in patients resembling PARADIGM-HF trial participants.

Characterization of a new genotype of Betapapillomavirus HPV 17 through L1, E7, E7 and LCR sequences

Human papillomavirus (HPV) exhibits epithelial and mucosal tropism. HPV type 17 belongs to the Betapapillomavirus genus and molecular cloning experiments have identified two subtypes (17a and 17b) isolated from epidermodysplasia verruciformis (EV). HPV subtypes are characterized by dissimilarities from 2 to 10% at the nucleotide level from their referenced HPV. The aim of this study was to characterize the L1, E6, E7 and LCR sequences from an isolate, which was recovered from the oral mucosa of an asymptomatic 63 year-old woman. The whole late gene 1 (L1) was amplified using several sets of primers. The complete early genes 6 and 7 (E6, E7) and the long control region (LCR) were amplified using specific primers. Potential binding sites for transcriptional factors within the LCR were also investigated. Within these sets, the DNA sequence was altered at 91 positions (68 in L1, 13 in E6, 8 in E7, and 2 in LCR sequences). L1 analysis showed high dissimilarity compared with the HPV 17 prototype, reaching 4% of nucleotide substitutions and leading to a probable third 17 subtype. The E6 oncoprotein presented the highest modification among the sequences studied, with four amino acid changes in comparison with the prototype isolate. One amino acid was modified at a position 62 (S-T), a zinc-binding domain (CxxC(C)29 CxxC). Our findings provide data on genetic variations seen in this genotype, reaching to dichotomic branching and pointing to an evolutionary process.

Modeling adult emergence and fecundity of factitious hosts under different food sources supports massive egg production management

Ephestia kuehniella (Lepidoptera, Pyralidae) and Sitotroga cerealella (Lepidoptera, Gelechiidae) are important factitious hosts used for production of biological control agents. Their differences in terms of biology and behavior require adjustments in their mass production, particularly when using corn or barley as food in grain or in bran. We modeled adult emergence, oviposition period and egg production along time after emergence, as a function of the food source. Significant differences between hosts or food type were found for these variables and for adult weight but not for sex ratio. Our results confirm the possibility of mass production of these hosts using corn or barley as food source. Integrating adult emergence patterns and age specific fecundity patterns into a single model, it is clear that rearing E. kuehniella on barley would result in the highest egg output in much shorter time than E. kuehniella on corn or S. cerealella on barley.

Risk Factors for Yeast Superinfection in the Treatment of Suspected Exit Site Infections: A Case-Control Study

Purpose

The risk of infection can be reduced in hemodialysis (HD) patients with central venous catheters (CVCs) by using prophylactic intranasal mupirocin or polysporin at the exit site. However, there are concerns about the potential emergence of resistant microorganisms. The purpose of our study was to determine if the use of polysporin double in the treatment of exit site infections was associated with the emergence of yeast positive exit site cultures.

Methods

In this case control study, we evaluated the risk of developing yeast positive exit site cultures after introducing a polysporin medical directive for the treatment of presumed exit site infections in our HD units. All HD patients using a CVC for blood access at the Ottawa Hospital were eligible for study. Demographic variables, use of polysporin, antibiotics and immunosuppressive medications were compared between those patients with yeast positive exit site cultures and controls.

Results

There was no differences in age, gender or diabetic status between the cases and controls. However, the use of polysporin, antibiotics and immunocompromised status were associated with an increased risk of yeast positive exit site cultures. The relative importance of each of these factors could not be determined using this study design and requires future prospective study.

Conclusions

The emergence of yeast positive exit site cultures after the introduction of a new medical directive at a tertiary care hospital highlights the difference between medications used for prophylaxis and those used for treatment of CVC infections in high risk dialysis patients.

Force spectroscopy unravels the role of ionic strength on DNA-cisplatin interaction: Modulating the binding parameters

In the present work we have gone a step forward in the understanding of the DNA-cisplatin interaction, investigating the role of the ionic strength on the complexes formation. To achieve this task, we use optical tweezers to perform force spectroscopy on the DNA-cisplatin complexes, determining their mechanical parameters as a function of the drug concentration in the sample for three different buffers. From such measurements, we determine the binding parameters and study their behavior as a function of the ionic strength. The equilibrium binding constant decreases with the counterion concentration ([Na]) and can be used to estimate the effective net charge of cisplatin in solution. The cooperativity degree of the binding reaction, on the other hand, increases with the ionic strength, as a result of the different conformational changes induced by the drug on the double-helix when binding under different buffer conditions. Such results can be used to modulate the drug binding to DNA, by appropriately setting the ionic strength of the surrounding buffer. The conclusions drawn provide significant new insights on the complex cooperative interactions between the DNA molecule and the class of platinum-based compounds, much used in chemotherapies.