Reconstitution of composite actin and keratin networks in vesicles.

Although cytoskeletal networks are interpenetrating and interacting in living cells, very little is understood as to the effect their interaction has on their properties. Here, as a step towards elucidating the synergistic cellular role of these structural proteins, we investigate isolated keratin and actin composites and show how the in vitro network formation of keratin influences the properties of actin networks and vice versa. By encapsulating purified composite networks into vesicles and separating the time scales of network formation we are able to demonstrate that the actin network stabilizes keratin networks by providing an elastic resistance to their collapse in vitro.

Ribavirin steady-state plasma level is a predictor of sustained virological response in hepatitis C-infected patients treated with direct-acting antivirals.

BACKGROUND: In the era of highly effective direct-acting antivirals (DAAs) for treatment of patients with chronic hepatitis C virus (HCV) infection, ribavirin (RBV) is still considered beneficial in certain patients. AIM: To assess the association between RBV steady-state plasma levels and sustained virological response (SVR). METHODS: Consecutive HCV-infected patients treated with DAAs plus RBV from four Dutch academic medical centres were enrolled. RBV steady-state plasma levels were prospectively measured at treatment week 8 using validated assays. Logistic regression analyses were performed to assess the influence of RBV steady-state plasma level on SVR, and RBV therapeutic range was explored using area under the ROC curve analyses. RESULTS: A total of 183 patients were included, of whom 85% had one or more difficult-to-cure characteristics (ie treatment experienced, HCV genotype 3, cirrhosis). The majority was treated with a sofosbuvir-based regimen and 163 (89%) patients achieved SVR. Median RBV dose was 12.9 (interquartile range 11.2-14.7) mg/kg/d, and median RBV steady-state plasma level was 2.66 (1.95-3.60) mg/L. In multivariable analyses, higher RBV steady-state plasma level (adjusted odds ratio 1.79 [95% CI 1.09-2.93]) was an independent predictor of SVR. With regard to the optimal RBV therapeutic range, 2.28 mg/L was the optimal lower cut-off for achieving SVR and 3.61 mg/L was the upper cut-off for preventing significant anaemia (Haemoglobin < 10 g/dL). CONCLUSION: In this cohort of mainly difficult-to-cure patients treated with DAAs plus RBV, higher RBV steady-state plasma level was an independent predictor of SVR.

The frequency of acute kidney injury in patients with chronic hepatitis C virus infection treated with sofosbuvir-based regimens.

BACKGROUND: Guidelines recommend withholding sofosbuvir (SOF) in patients with an estimated glomerular filtration rate (eGFR) of less than 30 mL/min. AIM: To assess the risk of acute kidney injury (AKI) in patients with no renal contraindications for SOF-based treatment. METHODS: This multicenter retrospective observational study included all consecutive patients that were treated with SOF-based or telaprevir/boceprevir (TVR/BOC)-based regimens at two tertiary university centers in North America. AKI was defined as an increase of ≥0.3 mg/dL (≥26.5 µmol/L) in serum creatinine level. Multivariable logistic regression analysis was used to identify risk factors for the occurrence of AKI. RESULTS: In total, 426 patients were included and treated with a SOF-based regimen (n=233, 54.7%) or TVR/BOC-based regimen (n=193, 45.3%). Among patients treated with a TVR/BOC-based regimen 34 (18%) of 193 patients experienced AKI compared to 26 (11%) of 233 patients treated with SOF-based regimens (P=.056). Multivariable logistic regression analysis showed that the presence of ascites (OR: 4.44, 95%CI: 1.46-13.54, P=.009) and the use of NSAIDs (OR: 4.47, 95%CI: 1.32-15.19, P=.016) were associated with a risk of AKI during SOF-based antiviral therapy. Creatinine levels returned to normal at end of follow-up in 23 (88%) of the 26 patients who experienced AKI with a SOF-based regimen and had a creatinine level available during follow-up. CONCLUSIONS: Although the risk for AKI was lower than for patients treated with TVR/BOC-based regimens, AKI was seen during 11% of SOF-based regimens and was mostly reversible. Patients with ascites and patients using NSAIDs have an increased risk for AKI during SOF-based antiviral therapy.

Twelve months of nightly zolpidem does not lead to rebound insomnia or withdrawal symptoms: a prospective placebo-controlled study.

Rebound insomnia, worsened sleep when discontinuing use of a hypnotic, is reported in some short-term studies. No study has prospectively assessed, using patient reports or nocturnal polysomnography (NPSG), the likelihood of rebound insomnia with chronic hypnotic use. The objectives of this study was to assess in primary insomniacs the likelihood of experiencing rebound insomnia and a withdrawal syndrome on repeated placebo substitutions over 12 months of nightly zolpidem use. A group of 33 primary insomniacs, without psychiatric disorders or drug and alcohol abuse, 32-65 years old, 15 men and 18 women, were randomized to take zolpidem 10 mg (n = 17) or placebo (n = 16) nightly for 12 months. In probes during months 1, 4, and 12, placebo was substituted for 7 consecutive nights in both the zolpidem and placebo groups. NPSGs were collected and Tyrer Bezodiazepine Withdrawal Symptom Questionnaires were completed on the first two discontinuation nights. Rebound insomnia was not observed on the first two and the seventh discontinuation nights and its likelihood did not increase over the 12 months of nightly zolpidem use. Some individuals did show rebound insomnia, approximately 30-40% of participants, but the percentage of 'rebounders' did not differ between the placebo and zolpidem groups and did not increase across 12 months. No clinically significant withdrawal symptoms on the Tyrer were observed on the discontinuation nights over the 12 months of nightly use. Chronic nightly hypnotic use at therapeutic doses by primary insomniacs does not lead to rebound insomnia or withdrawal symptoms.