Situation Report -66 HIGHLIGHTS• Three new countries/territories/areas from the Region of the Americas [1], and African Region [2] have reported cases of COVID-19.• The United Nations launched a US$2 billion COVID-19 Global Humanitarian Response Plan to support the world's most vulnerable countries. More information can be found here.• The WHO Director-General mentioned many key issues and action steps to effectively combat COVID-19, as well as maintaining physical distance but not social distance. More information can be found here.• WHO published the COVID-19: Operational guidance for maintaining essential health services during an outbreak and the Handbook for public health capacity-building at ground crossings and cross-border collaboration on 25 March 2020. All guidance documents can be found here. Western Pacific Region 99 058 confirmed (1292) 3540 deaths (22) European Region 250 287 confirmed (29 771) 13 950 deaths (1964) South-East Asia Region 2536 confirmed (192) 79 deaths (7) Eastern Mediterranean Region 32 442 confirmed (2811) 2162 deaths (154) Region of the Americas 75 712 confirmed (14 878) 1065 deaths (252) African Region 1937 confirmed (275) 31 deaths (2) WHO RISK ASSESSMENTGlobal Level Very High

No abstract

The evidence for loss of Ca2+ homeostasis due to neuronal degeneration is considerable and rapidly increasing. In this study, we try to evaluate the protective effect of tetrandrine (TET), an alkaloid isolated from the Chinese medicinal herb Radix Stephania tetrandrae S., on amyloid-beta protein (Abeta) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced cell death in SK-N-SH neuroblastoma cells. Both compounds reduced cell viability in a concentration-dependent manner after 72 h in culture. Cell proliferation in the presence of 20 microM Abeta or 0.4 mM MPTP was reduced to 58.3 +/- 4.9 or 54.9 +/- 5.5 %, respectively. TET (0.1, 0.5 and 1 microM) alone had no significant effect on cell survival; however, it prevented Abeta-induced cell death in a concentration-dependent manner. In contrast, TET failed to counteract MPTP-induced cytotoxicity. Also, an L-type calcium channel blocker, nimodipine, solely reversed Abeta-induced cell death. On the other hand, ELISA determination of mono-/oligo-nucleosomes accumulation showed that the mode of cell death evoked by Abeta was necrosis while that evoked by MPTP was presumably apoptosis. These results suggest that TET may mitigate the harmful effects of Abeta on cell survival, probably by interfering via the necrotic signal related to Ca2+ overloading through the L-type calcium channel.