A mouse-adapted enterovirus 71 (EV71) strain with increased virulence in mice, MP4, was generated after four serial passages of the parental EV71 strain 4643 in mice. Strain MP4 exhibited a larger plaque size, grew more rapidly, and was more cytotoxic in vitro than strain 4643. Although strains 4643 and MP4 both induced apoptosis of SK-N-SH human neuroblastoma cells, MP4 was more virulent than 4643 in 1-day-old mice (50% lethal doses, 10 2 and 10 4 PFU/mouse, respectively). Strain MP4 (5 ؋ 10 6 PFU/mouse), but not 4643, could orally infect 7-day-old mice, resulting in rear-limb paralysis followed by death 5 to 9 days after inoculation with the virus. Histopathologically, neuronal loss and apoptosis were evident in the spinal cords as well as the brain stems of the infected mice. The limb muscles displayed massive necrosis. There was early and transient virus replication in the intestines, whereas the spinal cord, brain, and muscle became the sites of viral replication during the late phase of the infection. Virus transmission occurred among infected and noninfected cagemates, as demonstrated by the occurrence of seroconversion and the presence of viable viruses in the stool samples of the latter. Protection against EV71 challenge was demonstrated following administration of hyperimmune serum 1 day after inoculation with the virus. Nucleotide sequence analysis of the genome of EV71 strain MP4 revealed four nucleotide changes on the 5 untranslated region, three on the VP2 region, and eight on the 2C region, resulting in one and four amino acid substitutions in the VP2 and 2C proteins, respectively.Enterovirus 71 (EV71), a neurotropic virus with undefined pathogenesis, has caused significant morbidity and mortality worldwide and especially in the Asia-Pacific region since it was first described in 1969 in the United States (1, 2). EV71 infections are generally mild, such as hand-foot-and-mouth disease (HFMD) and herpangina, but occasionally lead to severe diseases such as aseptic meningitis, poliomyelitis-like paralysis, and possibly fatal encephalitis in neonates. The outbreak of EV71 in Taiwan in 1998 killed 78 children, and since then EV71 infection has become endemic in Taiwan (8, 16). Brain stem encephalitis associated with pulmonary edema and cardiac insufficiency were the primary manifestations in patients with neurologic involvement (10, 16, 28). The predominant pathological findings were in the thalamus, pons, midbrain, medulla oblongata, and spinal cord, with intense neutrophil and mononuclear cell infiltrates. There was severe congestion with focal hemorrhage and edema in the lungs (21). Although EV71 was recovered from the mycocardium, there was only mild degeneration of the mycocardium. Neurogenic shock as a result of brain stem encephalitis has been proposed as the cause of pulmonary and cardiac complications (13,16). It has also been postulated that overwhelming virus replication combined with damage in tissues with the induction of toxic inflammatory cytokines is one possible pathogenesis (14,15,27)...

Baicalein (BA), one of the major compounds isolated from the root of Scutellaria baicalensis Gerogi, exhibits various pharmacological effects, such as anti-oxidant, anti-inflammatory, and anticancer effects. In this study, we found that BA reduced cell viability and increased apoptosis in ovarian cancer cells. Treatment of cells with BA enhanced microtubule-associated protein light chain 3-II (LC3-II) expression, acidic vesicular organelle and GFP-LC3 fluorescence dot accumulation. Combined treatment with chloroquine and BA apparently reduced cell viability and increased the cleavage of poly (ADPribose) polymerase (PARP) in both HEY and A2780 ovarian cancer cell lines, indicating that BA induces a protective autophagy in these cells. Knockdown of Beclin 1 by siRNA remarkably decreased BA-induced LC3-II lipidation. In addition, we found an increase in the phosphorylation of extracellular signal-regulated kinase (ERK, Thr202/Thr204) and AKT (Ser473) after BA treatment, and inhibition of ERK activation by the pharmacological inhibitor U0126 or ERK siRNA blocked BA-induced autophagy. Taken together, these results suggest that BA induces Beclin 1- and ERK-dependent autophagy in ovarian cancer cells.