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At the time of writing this commentary (February 2020), the coronavirus COVID-19 epidemic has already resulted in more fatalities compared with the SARS and MERS coronavirus epidemics combined. Therapeutics that may assist to contain its rapid spread and reduce its high mortality rates are urgently needed. Developing vaccines against the SARS-CoV-2 virus may take many months. Moreover, vaccines based on viral-encoded peptides may not be effective against future coronavirus epidemics, as virus mutations could make them futile. Indeed, new Influenza virus strains emerge every year, requiring new immunizations. A tentative suggestion based on existing therapeutics, which would likely be resistant to new coronavirus mutations, is to use available angiotensin receptor 1 (AT1R) blockers, such as losartan, as therapeutics for reducing the aggressiveness and mortality from SARS-CoV-2 virus infections. This idea is based on observations that the angiotensin-converting enzyme 2 (ACE2) very likely serves as the binding site for SARS-CoV-2, the strain implicated in the current COVID-19 epidemic, similarly to strain SARS-CoV implicated in the 2002-2003 SARS epidemic. This commentary elaborates on the idea of considering AT1Rblockers as tentative treatment for SARS-CoV-2 infections, and proposes a research direction based on datamining of clinical patient records for assessing its feasibility.

Contemporary Jews comprise an aggregate of ethno-religious communities whose worldwide members identify with each other through various shared religious, historical and cultural traditions. Historical evidence suggests common origins in the Middle East, followed by migrations leading to the establishment of communities of Jews in Europe, Africa and Asia, in what is termed the Jewish Diaspora. This complex demographic history imposes special challenges in attempting to address the genetic structure of the Jewish people. Although many genetic studies have shed light on Jewish origins and on diseases prevalent among Jewish communities, including studies focusing on uniparentally and biparentally inherited markers, genome-wide patterns of variation across the vast geographic span of Jewish Diaspora communities and their respective neighbours have yet to be addressed. Here we use high-density bead arrays to genotype individuals from 14 Jewish Diaspora communities and compare these patterns of genome-wide diversity with those from 69 Old World non-Jewish populations, of which 25 have not previously been reported. These samples were carefully chosen to provide comprehensive comparisons between Jewish and non-Jewish populations in the Diaspora, as well as with non-Jewish populations from the Middle East and north Africa. Principal component and structure-like analyses identify previously unrecognized genetic substructure within the Middle East. Most Jewish samples form a remarkably tight subcluster that overlies Druze and Cypriot samples but not samples from other Levantine populations or paired Diaspora host populations. In contrast, Ethiopian Jews (Beta Israel) and Indian Jews (Bene Israel and Cochini) cluster with neighbouring autochthonous populations in Ethiopia and western India, respectively, despite a clear paternal link between the Bene Israel and the Levant. These results cast light on the variegated genetic architecture of the Middle East, and trace the origins of most Jewish Diaspora communities to the Levant.

Previous studies have shown that neuroblastoma cells and several types of primary neuronal cells in culture rapidly extend neurites when switched from serum-containing to serum-free medium. The present studies on cloned neuroblastoma cells show that thrombin blocked this spontaneous differentiation at 2 nM with a half-maximal potency of 50 pM. This required the catalytic activity of thrombin and was reversed upon thrombin removal. Thrombin also caused cells in serum-free medium to retract their neurites at equally low concentrations. Two other serine proteases, urokinase and plasmin, did not block or reverse neurite extension even at 100-fold higher concentrations. A specific assay for thrombin indicated that thrombin detected in serum-containing medium from neuroblastoma cultures was derived from serum and that it was likely responsible for much of the known capacity of serum to maintain neuroblastoma cells in a nondifferentiated state. This was supported by the rinding that heparin addition reduced the thrombin concentration in serum-containing medium and stimulated neurite outgrowth from neuroblastoma cells in serum-containing medium. Studies on the ability of thrombin to modulate neurite outgrowth by other agents showed that it blocked and reversed the neurite outgrowth activity of two thrombin inhibitors: protease nexin-1 (which is identical to glial-derived neurite-promoting factor) and hirudin. Thrombin, however, did not block the neurite-promoting activity of dibutyryl cAMP or prostaglandin El. These results suggest a specific role for thrombin in control of neurite outgrowth.Cloned murine neuroblastoma cells have been widely used as a model system for neuronal cells since they can be induced to differentiate in culture by stimuli such as dibutyryl cAMP (Bt2cAMP) (1-3), prostaglandin E1 (PGE1) (4), and serum removal (5)(6)(7)(8)(9). Differentiation is observed morphologically as neurite extension, a process that requires assembly of microtubules (10) and is blocked by microtubule-disrupting agents (7, 11). Neurite outgrowth is paralleled by increased activities of several enzymes related to neural function such as tyrosine hydroxylase, choline acetyltransferase, and acetylcholine esterase (12,13 In view of these considerations, we evaluated the hypothesis that thrombin might induce neurite retraction and modulate neurite outgrowth by certain agents. Cloned neuroblastoma cells were used in these studies to determine whether thrombin had direct effects on neurite outgrowth in the absence of other cell types. MATERIALS AND METHODSMaterials. Purified human a-thrombin (2750 NIH units/mg) was generously supplied by John W. Fenton II (New York State Department of Health, Albany). Thrombin, whose catalytic site serine residue was derivatized with a diisopropylphospho group (DIP-thrombin), was prepared as described (25). Protease nexin-1 (PN-1) was purified from serum-free medium conditioned by normal human foreskin fibroblasts cultured on microcarrier beads as described (26) (GIBCO), penicillin G (100 u...

SummaryMitochondrial aldehyde dehydrogenase (ALDH2) is one of the most important enzymes in human alcohol metabolism. The oriental ALDH2 * 504Lys variant functions as a dominant negative, greatly reducing activity in heterozygotes and abolishing activity in homozygotes. This allele is associated with serious disorders such as alcohol liver disease, late onset Alzheimer disease, colorectal cancer, and esophageal cancer, and is best known for protection against alcoholism. Many hundreds of papers in various languages have been published on this variant, providing allele frequency data for many different populations. To develop a highly refined global geographic distribution of ALDH2 * 504Lys, we have collected new data on 4,091 individuals from 86 population samples and assembled published data on a total of 80,691 individuals from 366 population samples. The allele is essentially absent in all parts of the world except East Asia. The ALDH2 * 504Lys allele has its highest frequency in Southeast China, and occurs in most areas of China, Japan, Korea, Mongolia, and Indochina with frequencies gradually declining radially from Southeast China. As the indigenous populations in South China have much lower frequencies than the southern Han migrants from Central China, we conclude that ALDH2 * 504Lys was carried by Han Chinese as they spread throughout East Asia. Esophageal cancer, with its highest incidence in East Asia, may be associated with ALDH2 * 504Lys because of a toxic effect of increased acetaldehyde in the tissue where ingested ethanol has its highest concentration. While the distributions of esophageal cancer and ALDH2 * 504Lys do not precisely correlate, that does not disprove the hypothesis. In general the study of fine scale geographic distributions of ALDH2 * 504Lys and diseases may help in understanding the multiple relationships among genes, diseases, environments, and cultures.