RESUMEN
An outbreak of clusters of viral pneumonia due to a novel coronavirus (2019-nCoV / SARS-CoV-2) happened in Wuhan, Hubei Province in China in December 2019. Since the outbreak, several groups reported estimated R0 of Coronavirus Disease 2019 (COVID-19) and generated valuable prediction for the early phase of this outbreak. After implementation of strict prevention and control measures in China, new estimation is needed. An infectious disease dynamics SEIR (Susceptible, Exposed, Infectious and Removed) model was applied to estimate the epidemic trend in Wuhan, China under two assumptions of Rt. In the first assumption, Rt was assumed to maintain over 1. The estimated number of infections would continue to increase throughout February without any indication of dropping with Rt = 1.9, 2.6 or 3.1. The number of infections would reach 11,044, 70,258 and 227,989, respectively, by 29 February 2020. In the second assumption, Rt was assumed to gradually decrease at different phases from high level of transmission (Rt = 3.1, 2.6 and 1.9) to below 1 (Rt = 0.9 or 0.5) owing to increasingly implemented public heath intervention. Several phases were divided by the dates when various levels of prevention and control measures were taken in effect in Wuhan. The estimated number of infections would reach the peak in late February, which is 58,077-84,520 or 55,869-81,393. Whether or not the peak of the number of infections would occur in February 2020 may be an important index for evaluating the sufficiency of the current measures taken in China. Regardless of the occurrence of the peak, the currently strict measures in Wuhan should be continuously implemented and necessary strict public health measures should be applied in other locations in China with high number of COVID-19 cases, in order to reduce Rt to an ideal level and control the infection.
RESUMEN
Objective To investigate the effect of penehyclidine hydrochloride (PHCD) on tramadol dependence and c-fos,△ FosB and M5 receptor expression in relevant brain regions in rats.Methods Thirty male adult SD rats weighing 180-220 g were randomly assigned to 3 groups (n =10 each):control group (group C),tramadol dependence group (group T) and PHCD group (group P).Tramadol dependence was induced by subcutaneous 10 mg/kg once a day for 7 consecutive days in groups T and P.PHCD 1.5 mg/kg was injected intraperitoneally on day 8 in group P,while in groups C and T the equal volume of normal saline was injected intraperitoneally instead of PHCD.The rats underwent conditioned place perference test at 30 min after intraperitoneal injection.The time spent in drug-paired side (gray area) was recorded.The rats were sacrificed after the conditioned place perference testand the brain was removed.The relevant brain regions (ventral tegmental area,prefrontal cortex,nucleus accumbens )were separated for determination of c-fos,△ FosB expression by Western blot and M5 receptor mRNA expression by RT-PCR.Results Compared with group C,the time spent in the drug-paired side (gray area) was significantly prolonged,and c-fos,△FosB and M5 receptor mRNA expressions were up-regulated in group T,△FosB and Ms receptor mRNA expressions were down-regulated in group P ( P ＜ 0.05 or 0.01 ).There was no significant difference in time spent in the drug-paired side (gray area) and c-fos expression between groups C and P( P ＞ 0.05).Compared with group T,the time spent in the drug-paired side (gray area) was significantly shortened,and c-fos,△ FosB and M5 receptor mRNA expressions were down-regulated in group P (P ＜0.01).Conclusion PHCD can significantly inhibit tramadol dependence by down-regulating c-fos,△FosB and M5 receptor expression in relevant brain regions.