LitCovid-sentences  

PMC:7408073 / 39383-43824 JSONTXT 11 Projects

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Id Subject Object Predicate Lexical cue
T188 0-185 Sentence denotes ACE2, as well as ACE, is a zinc metalloprotease that can be inhibited by zinc chelating EDTA and activated by high concentrations of chloride or fluoride anions and zinc cation [79,90].
T189 186-250 Sentence denotes Indeed, both enzymes have chloride- and zinc-binding sites [90].
T190 251-375 Sentence denotes It is conceivable that these sites are responsible for the anion and zinc activation effect in both homologous enzymes [90].
T191 376-634 Sentence denotes However, the presence of chloride ions increases Ang I cleavage by ACE and ACE2 (increasing both Ang II and Ang (1–9)) and decreases Ang II cleavage by ACE2, suggesting that chloride induces specific ACE2 conformational changes in its active site (see [44]).
T192 635-805 Sentence denotes To this regard, in plasma samples of COVID–19 patients, chloride range is usually normal or slightly higher (99.6–107.0 mmol/L) than normal values (96.–106.0 mmol/L) [5].
T193 806-892 Sentence denotes Unfortunately, I was not able to find plasma zinc concentrations in COVID-19 patients.
T194 893-1012 Sentence denotes Zinc is involved in several cellular activities and its systemic concentration is tightly regulated by several factors.
T195 1013-1613 Sentence denotes Of interest, the major transporter/reservoir of zinc in plasma is albumin [91], a protein that was detected at significantly low concentrations in SARS-CoV-2 as well as severe adult respiratory distress syndrome (ARDS, a COVID-19-like disease) (usually < 3.5 g/dL, normal range 3.5–5.4) and inflammatory bowel disease (IBD, a disease with increased ACE2 activity) [6,8,66,92] Since most of zinc in plasma is sequestered by albumin, the total amount of plasma zinc mostly depends on albumin concentration and even small changes in albumin’s capacity for zinc binding may have significant consequences.
T196 1614-1836 Sentence denotes To this regard, reduced concentrations of plasma albumin is believed to increase plasma levels of free zinc, while reducing the total plasma zinc concentrations [91], a condition that was observed in ARDS patients [93,94].
T197 1837-1979 Sentence denotes Indeed, albumin can potentially deplete free bioavailable forms of zinc; vice versa, hypoalbuminaemia may increase free zinc levels in plasma.
T198 1980-2115 Sentence denotes Therefore, some ARDS patients with low levels of both total zinc and albumin might have rather higher than lower free zinc levels [93].
T199 2116-2330 Sentence denotes The free zinc concentration, which describes the fraction of zinc that is loosely bound and easily exchangeable, represents the highly bioavailable (and toxic) part of plasma zinc but it is not clinically detected.
T200 2331-2411 Sentence denotes To that end, zinc/albumin ratio might be a surrogate marker of free zinc levels.
T201 2412-2551 Sentence denotes Indeed, only recently it was described a fluorescence-based method for determining the free zinc concentration in human serum samples [95].
T202 2552-2675 Sentence denotes With this method it was shown that free zinc concentration in sera from females was significantly lower than in males [95].
T203 2676-2825 Sentence denotes Moreover, free zinc concentration did correlate neither with total serum concentrations of zinc (or other metal ions such as iron) nor with age [95].
T204 2826-3049 Sentence denotes Notably, increased plasma zinc bioavailability consequent to reduced albumin levels induces zinc import into cells and likely increases the cellular functions associated to cellular zinc concentrations such as ACE and ACE2.
T205 3050-3236 Sentence denotes Indeed, enzymatic activity of both enzymes seems significantly upregulated in ARDS patients as detected by analysis of Ang peptide concentrations in plasma (see Box later in ARDS topic).
T206 3237-3475 Sentence denotes In addition, serum albumin levels in COVID-19 were usually very low (in severe forms is usually < 3.1 g/dL) [6,8], raising the possibility of a negative correlation between albumin concentration in plasma and increase of the RAS activity.
T207 3476-3798 Sentence denotes In line with these hypotheses, both asthmatic/allergic disease patients and chronic kidney disease patients without a history of cardiovascular disease, which are protected from developing COVID-19, showed a significant decrease in both circulating zinc levels and ACE2 activity as compared to normal values [96,97,98,99].
T208 3799-4105 Sentence denotes Interestingly, chronic renal disease patients with low zinc levels had normal concentrations of albumin but higher urinary zinc excretion than healthy controls [97], suggesting that low ACE2 activity in chronic renal diseases (and protection from SARS) might derive from a higher free Zn2+ renal excretion.
T209 4106-4243 Sentence denotes A similar mechanism mediated by a reduction of extracellular levels of free Zn2+ might be hypothesised for asthma patients, as well [98].
T210 4244-4441 Sentence denotes Unfortunately, I could not find information on plasma albumin concentrations for asthma patients; nevertheless, we might suppose that in these patients the albumin concentration is in normal range.