Due to the emergence of highly pathogenic and oseltamivir-resistant influenza viruses, there is an urgent need to develop new anti-influenza agents. Herein, five sub-series of oseltamivir derivatives were designed and synthesized to improve their activity towards drug-resistant viral strains by further exploiting the 150-cavity in the neuraminidases (NAs). The bioassay results showed that compound 21h exhibited antiviral activities similar to or better than those of oseltamivir carboxylate (OSC) against H5N1, H5N2, H5N6 and H5N8. Besides, 21h was 5-to 86-fold more potent than OSC toward N1, N8, and N1-H274Y mutant NAs in the inhibitory assays. Computational studies provided a plausible rationale for the high potency of 21h against group-1 and N1-H274Y NAs. In addition, 21h demonstrated acceptable oral bioavailability, low acute toxicity and potent antiviral activity in vivo, and high metabolic stability. Overall, above excellent profiles make 21h a promising drug candidate for the treatment of influenza virus infection.

We examined esophageal cancer patients who received enteral nutrition (EN) to evaluate the validity of early EN compared to delayed EN, and to determine the appropriate time to start EN. A total of 208 esophagectomy patients who received EN postoperatively were divided into three groups (Group 1, 2 and 3) based on whether they received EN within 48 h, 48 h–72 h or more than 72 h, respectively. The postoperative complications, length of hospital stay (LOH), days for first fecal passage, cost of hospitalization, and the difference in serum albumin values between pre-operation and post-operation were all recorded. The statistical analyses were performed using the t-test, the Mann-Whitney U test and the chi square test. Statistical significance was defined as p < 0.05. Group 1 had the lowest thoracic drainage volume, the earliest first fecal passage, and the lowest LOH and hospitalization expenses of the three groups. The incidence of pneumonia was by far the highest in Group 3 (p = 0.019). Finally, all the postoperative outcomes of nutritional conditions were the worst by a significant margin in Group 3. It is therefore safe and valid to start early enteral nutrition within 48 h for postoperative esophageal cancer patients.

On the basis of our earlier discovery of N1-selective inhibitors, the 150-cavity of influenza virus neuraminidases (NAs) could be further exploited to yield more potent oseltamivir derivatives. Among the synthesized compounds, 15b and 15c were exceptionally active against both group-1 and -2 NAs. Especially for 09N1, N2, N6, and N9 subtypes, they showed 6.80-12.47 and 1.20-3.94 times greater activity than oseltamivir carboxylate (OSC). They also showed greater inhibitory activity than OSC toward H274Y and E119V variant. In cellular assays, they exhibited greater potency than OSC toward H5N1, H5N2, H5N6, and H5N8 viruses. 15b demonstrated high metabolic stability, low cytotoxicity in vitro, and low acute toxicity in mice. Computational modeling and molecular dynamics studies provided insights into the role of R group of 15b in improving potency toward group-1 and -2 NAs. We believe the successful exploitation of the 150-cavity of NAs represents an important breakthrough in the development of more potent anti-influenza agents.

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