Diacylglycerol acyltransferase-1 localizes hepatitis C virus NS5A protein to lipid droplets and enhances NS5A interaction with the viral capsid core.

The triglyceride-synthesizing enzyme acyl CoA:diacylglycerol acyltransferase 1 (DGAT1) plays a critical role in hepatitis C virus (HCV) infection by recruiting the HCV capsid protein core onto the surface of cellular lipid droplets (LDs). Here we find a new interaction between the non-structural protein NS5A and DGAT1 and show that the trafficking of NS5A to LDs depends on DGAT1 activity. DGAT1 forms a complex with NS5A and core and facilitates the interaction between both viral proteins. A catalytically inactive mutant of DGAT1 (H426A) blocks the localization of NS5A, but not core, to LDs in a dominant-negative manner and impairs the release of infectious viral particles, underscoring the importance of DGAT1-mediated translocation of NS5A to LDs in viral particle production. We propose a model whereby DGAT1 serves as a cellular hub for HCV core and NS5A proteins, guiding both onto the surface of the same subset of LDs, those generated by DGAT1. These results highlight the critical role of DGAT1 as a host factor for HCV infection and as a potential drug target for antiviral therapy.

HCV infection induces a unique hepatic innate immune response associated with robust production of type III interferons.

BACKGROUND & AIMS: Polymorphisms in the IL28B gene have been associated with clearance of hepatitis C virus (HCV), indicating a role for type III interferons (IFNs) in HCV infection. Little is known about the function of type III IFNs in intrinsic antiviral innate immunity. METHODS: We used in vivo and in vitro models to characterize the role of the type III IFNs in HCV infection and analyzed gene expression in liver biopsy samples from HCV-infected chimpanzees and patients. Messenger RNA and protein expression were studied in HCV-infected hepatoma cell lines and primary human hepatocytes. RESULTS: HCV infection of primary human hepatocytes induced production of chemokines and type III IFNs, including interleukin (IL)-28, and led to expression of IFN-stimulated genes (ISGs). Chimpanzees infected with HCV showed rapid induction of hepatic type III IFN, associated with up-regulation of ISGs and minimal induction of type I IFNs. In liver biopsy specimens from HCV-infected patients, hepatic expression of IL-28 correlated with levels of ISGs but not of type I IFNs. HCV infection produced extensive changes with gene expression in addition to ISGs in primary human hepatocytes. The induction of type III IFNs is regulated by IFN regulatory factor 3 and nuclear factor κB. Type III IFNs up-regulate ISGs with a different kinetic profile than type 1 IFNs and induce a distinct set of genes, which might account for their functional differences. CONCLUSIONS: HCV infection results predominantly in induction of type III IFNs in livers of humans and chimpanzees; the level of induction correlates with hepatic levels of ISGs. These findings might account for the association among IL-28, level of ISGs, and recovery from HCV infection and provide a therapeutic strategy for patients who do not respond to IFN therapy.

A prospective comparative study to evaluate safety and efficacy of pneumatic versus laser lithotripsy in mini-percutaneous nephrolithotomy.

OBJECTIVE: The choice of lithotripter is an important part of planning in mini-percutaneous nephrolithotomy (mini perc) as the operating time is prolonged due to reduced sheath size and smaller working channel. Previous studies mostly reported the use of laser lithotripter for stone fragmentation while the literature on pneumatic lithotripter use in miniperc is scant. METHODS: In this study, we compared the efficacy and safety of the laser lithotripter (LL) vs pneumatic lithotripter (PL) in miniperc for small to medium-sized renal/upper ureteric stones (size: 1-2 cm). All consecutive patients who underwent miniperc from September 2020 to August 2022 were included in the study. Laser lithotripter was used in 81 patients (group LL), while pneumatic was used in 75 patients (group PL). The preoperative, operative, and postoperative findings were compared. RESULTS: Baseline patient characteristics (age, sex, body mass index, and co-morbid illness) and stone characteristics (size, stone number, laterality, presence of staghorn calculi, presence of hydronephrosis, Guy's stone scores) were comparable between the two groups (P>0.05). The mean operative time was comparable (P=0.38) while the mean fragmentation time was significantly higher in the PL group (35.42±6.34 vs 28.96±2.82 minutes; P<0.01). 29.3% required forceps/basket for stone removal in PL group as compared to 7.4% in LL group (P=0.02). Mean VAS (Visual Analog Scale) score on the first post-operative day, stone clearance, drop in hemoglobin, average hospital stay, stone clearance at 3 months postoperative, and complications were comparable (P>0.05). CONCLUSION: Lithotripsy with pneumatic lithotripter can be used as an equally effective and safe alternative to laser lithotripter in mini-perc for treatment of small-medium sized renal/upper ureteric calculi.

River space: A hydro-bio-geomorphic framework for sustainable river-floodplain management.

The lateral dimension of an alluvial river - floodplains - provides a plethora of goods and services for human needs. Also, it supports the richest and diverse riverine ecosystems on Earth. But over-utilization of floodplain resources had impacted functions of river system adversely. So, the present study attempts to formulate a hydro-bio-geomorphological framework to assess the lateral dimension of a river system for sustainable management of river-floodplains and termed as river space in this paper. The study illustrates river space at seven hydro-meteorological sites situated on the main stem of the Ganga river in the ~750 km stretch that lies between Haridwar and Prayagraj cities. For hydrological aspect, the flood frequency analysis is used to identify flood inundation widths for floods of different return periods with the help of the rating curve and derived cross-section from satellite imagery. Bio-geomorphological aspects are taken into consideration for corroborating the hydrologically assessed river widths (lateral dimension). The present study suggests that the minimum river space should be equal to the lateral width corresponding to the 1-year return period flood. In the present hydro-meteorological sites in the middle Ganga plains, it ranges from 2 to 21 km. Overall, the present study gives an insight of a simple and logical approach that could be beneficial for the biomic restoration of rivers and their floodplains.

Stability of Meropenem and Piperacillin/Tazobactam with Heparin in Various Peritoneal Dialysis Solutions.

BACKGROUND: Infections caused by ceftazidime-resistant Pseudomonas and extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacteria are increasing worldwide. Meropenem and piperacillin/tazobactam (PIP/TZB) are recommended for the treatment of peritoneal dialysis-associated peritonitis (PDAP) caused by ceftazidime-resistant Pseudomonas and other resistant gram-negative bacteria. Patients may also receive intraperitoneal heparin to prevent occlusion of their catheters. However, the stability of meropenem or PIP/TZB, in combination with heparin, in different types of peritoneal dialysis (PD) solutions used in clinical practice is currently unknown. Therefore, we investigated the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. METHODS: A total of 15 PD bags (3 bags for each type of PD solution) containing meropenem and heparin and 24 PD bags (3 bags for each type of PD solution) containing PIP/TZB and heparin were prepared and stored at 4°C for 168 hours. The same bags were stored at 25°C for 3 hours followed by 10 hours at 37°C. An aliquot withdrawn before storage and at defined time points was analyzed for the concentration of meropenem, PIP, TZB, and heparin using high-performance liquid chromatography. Samples were also analysed for particle content, pH and color change, and the anticoagulant activity of heparin. RESULTS: Meropenem and heparin retained more than 90% of their initial concentration in 4 out of 5 types of PD solutions when stored at 4°C for 168 hours, followed by storage at 25°C for 3 hours and then at 37°C for 10 hours. Piperacillin/tazobactam and heparin were found to be stable in all 8 types of PD solutions when stored under the same conditions. Heparin retained more than 98% of its initial anticoagulant activity throughout the study period. No evidence of particle formation, color change, or pH change was observed at any time under the storage conditions employed in the study. CONCLUSIONS: This study provides clinically important information on the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. The use of meropenem-heparin admixed in pH-neutral PD solutions for the treatment of PDAP should be avoided, given the observed suboptimal stability of meropenem.