ABSTRACT
To study the antiviral effect of Hypericum perforatum L. extract (HPE) on influenza A virus (IAV) (H1N1) in vitro and in vivo. Cytopathic effect (CPE) and neutral red (NR) dye uptake were used to examine the antiviral effect of HPE on Madin Darby Canine Kidney (MDCK) cells which were infected with IAV in vitro. HPE was effective against influenza A virus (IAV) in vitro, with a 50% effective concentration (EC50) of 40 μg/mL. The mean 50% cytotoxic concentration (CC50) in the MDCK used in these experiments was 1.5 mg/mL. Ribavirin was run in parallel with EC50 values of 5.0 μg/mL; the mean CC50 for ribavirin was 520 μg/mL. Oral gavage administrations of HPE or ribavirin to mice infected with the IAV were highly effective in preventing death, slowing the decline of arterial oxygen saturation, inhibiting lung consolidation and reducing lung virus titers. The minimum effective dose of HPE in these studies was 31.25 mg/kg/day, which was administered twice daily for 5 d beginning 4 h prior to virus exposure. Below a dosage of 2000 mg/kg/day, almost all treated mice survived, which suggests that HPE is of low toxicity. Ribavirin's minimum effective dose was 40 mg/kg/day with the LD50 determined to be 200 mg/kg/day. Delay of the initiation of either HPE or ribavirin therapy, using approximately 1/3 LD50 dose each time, could still be protective as late as 48 h after exposure to the IAV. While both agents appeared to have similar efficacy against IAV infections, HPE was considered to be less toxic and may warrant further evaluation as a possible therapy for influenza.
ABSTRACT
@# Objective To investigate the risk factors related with chronic stuttering of children lasting more than 6 months.MethodsThe data of 109 children of 2～10 years old with chronic stuttering lasting more than 6 months and 68 children with developmental stuttering lasting less than 6 months were analyzed.ResultsThe minor symptom and escape behavior in the stuttering children group were significantly more than children in the control group. The risk factors related with chronic stuttering showed by Logistic regression analysis were as follows: care about their stuttering, not professional advice and training, the attitude of parents on stuttering, family history, incorrect rectifying methods, few family members, improper family bring-up environment.ConclusionChildren with minor symptom and escape behavior concurrent with stuttering, care about their stuttering and with family record, are susceptible to chronic stuttering. Following factors are found important to chronic stuttering: professional advice and training, the attitude of parents to stuttering, methods of parents correcting stuttering, number of family members, bring-up environment of family.