The aim of this study was to analyze the correlation between dynamic changes in the nasopharyngeal viral load of patients infected with the new coronavirus causing pneumonia and lymphocyte count disease severity. Cases newly diagnosed with COVI<em>D</em>-19 at the First Affiliated Hospital of Nanchang University from January <em>2</em>0<em>2</em>0 to February <em>2</em>0<em>2</em>0 were analyzed retrospectively. Quantitative real-time polymerase chain reaction was used to determine severe acute respiratory syndrome coronavirus <em>2</em> (SARS-CoV-<em>2</em>) from throat swab sample ΔCT values; lymphocyte and lymphocyte subset counts, coagulation system factor levels, myocardial injury indexes, and laboratory biochemical indicators were compared between the mild group and the severe group. The correlation between the relative load of nasopharyngeal SARS-CoV-<em>2</em> RNA and severe disease symptoms was analyzed. Of the 76 patients, 49 were male and <em>2</em>7 were female. The lymphocyte, C<em>D</em>4⁺ T lymphocyte, and C<em>D</em>8⁺ T lymphocyte counts all differed significantly between the two groups (<i>p</i> < 0.001), as did differences in interleukin (IL)-<em>2</em>R, IL-6, and IL-8 levels (<i>p</i> = 0.0<em>2</em><em>2</em>, 0.0<em>2</em>6, and 0.01<em>2</em>, respectively). Moreover, there were significant differences in prothrombin time, <em>D</em>-<em>dimer</em>, and fibrinogen levels between the mild group and the severe group (<i>p</i> = 0.0<em>2</em>9, 0.006, and <0.001, respectively), and in lactate dehydrogenase and troponin (<i>p</i> < 0.001 and <i>p</i> = 0.007, respectively). SARS-CoV-<em>2</em> RNA load and lymphocyte count, C<em>D</em>4⁺ T lymphocyte count, and C<em>D</em>8⁺ T lymphocyte count were linearly negatively correlated (<i>p</i> < 0.001). SARS-CoV-<em>2</em> RNA load was positively correlated with IL-<em>2</em>R, prothrombin time, lactate dehydrogenase, and hypersensitive troponin T (<i>p</i> = 0.00<em>2</em>, <i>p</i> = 0.009, and <i>p</i> < 0.001, respectively). In addition, the time that it took for the nucleic acid test to turn negative was significantly shorter for patients in the mild group than for those in the severe group (<i>Z</i> = -6.713, <i>p</i> < 0.001). In conclusion, relative SARS-CoV-<em>2</em> RNA load in the nasopharynx is closely related to COVI<em>D</em>-19 severity. If the relative RNA load was higher, the lymphocyte count was lower, organ damage was greater, and the time it took for the nucleic acid test to turn negative was longer.

<AbstractText>This retrospective study aimed to analysis clinical characteristics and outcomes of cancer patients with novel coronavirus disease-19 (COVI<em>D</em>-19).</AbstractText><AbstractText>Medical records, laboratory results and radiologic findings of 5<em>2</em> cancer patients with COVI<em>D</em>-19 were collected, clinical characteristics and outcomes were summarized.</AbstractText><p><div><b>RESULTS</b></div>A total of 5<em>2</em> cancer patients with COVI<em>D</em>-19 were included. Median age of 5<em>2</em> cancer patients with COVI<em>D</em>-19 was 63 years (34-98). 33(63.5%) patients were mild and 19(36.5%) were severe/critical. Lung cancer was the most frequent cancer type (10, 19.<em>2</em>%). The common symptoms were as follows: fever (<em>2</em>5%), dry cough (17.3%), chest distress (11.5%) and fatigue (9.6%).There were 33(63.5%) patients had comorbidities, the most common symptom was hypertension (17, 51.5%). <em>2</em>6(78.8%) patients developed pneumonia on admission. Lymphocytes (0.6×10⁹ /L) decreased in both mild and severe/critical patients. Median levels of <em>D</em>-<em>dimer</em>, C-reactive protein(CRP), procalcitonin (PCT) and lactate dehydrogenase(L<em>D</em>H) were <em>2</em>.8 mg/L, 70.5 mg/L, 0.3 ng/mL, and 318 U/L respectively, which increased significantly in severe/critical patients compared to the mild patients. Interleukin 6(IL-6) (1<em>2</em>.6 pg/ml) increased in both mild and severe/critical patients, there was a significant difference between them. Complications were observed in <em>2</em>9(55.8%) patients, such as liver injury (19, 36.5%), acute respiratory distress syndrome (AR<em>D</em>S) (9, 17.3%), sepsis (8, 15.4%), myocardial injury (8, 15.4%), renal insufficiency (4, 7.7%), and multiple organ dysfunction syndrome (MO<em>D</em>S) (3, 5.8%).11(<em>2</em>1.<em>2</em>%) cancer patients died.</p><AbstractText>The infection rate of severe acute respiratory syndrome coronavirus <em>2</em>(SARS-COV-<em>2</em>) in cancer patients was higher than the general population, cancer patients with COVI<em>D</em>-19 showed deteriorating conditions and poor outcomes. This article is protected by copyright. All rights reserved.</AbstractText>

Human CD34(+) hematopoietic precursor cells cultured on <em>delta</em>-like ligand 1 expressing OP9 (OP9-DL1) stromal cells differentiate to T lineage cells. The nature of the T cells generated in these cultures has not been studied in detail. Since these cultures do not contain thymic epithelial cells which are the main cell type mediating positive selection in vivo, generation of conventional helper CD4(+) and cytotoxic CD8(+) TCRalphabeta cells is not expected. Phenotypically mature CD<em>2</em>7(+)CD1(-) TCRgamma<em>delta</em> as well as TCRalphabeta cells were generated in OP9-DL1 cultures. CD8 and few mature CD4 single-positive TCRalphabeta cells were observed. Mature CD8 single-positive cells consisted of two subpopulations: one expressing mainly CD8alphabeta and one expressing CD8alphaalpha <em>dimers</em>. TCRalphabeta CD8alphaalpha and TCRgamma<em>delta</em> cells both expressed the IL<em>2</em>Rbeta receptor constitutively and proliferated on IL-15, a characteristic of unconventional T cells. CD8alphabeta(+) and CD4(+) TCRalphabeta cells were unresponsive to IL-15, but could be expanded upon TCR stimulation as mature CD8alphabeta(+) and CD4(+) T cells. These T cells had the characteristics of conventional T cells: CD4(+) cells expressed ThPOK, CD40L, and high levels of IL-<em>2</em> and IL-4; CD8(+) cells expressed Eomes, Runx3, and high levels of granzyme, perforin, and IFN-gamma. Induction of murine or human MHC class I expression on OP9-DL1 cells had no influence on the differentiation of mature CD8(+) cells. Similarly, the presence of dendritic cells was not required for the generation of mature CD4(+) or CD8(+) T cells. These data suggest that positive selection of these cells is induced by interaction between T precursor cells.

Non-structural protein 1 from influenza A virus, NS1A, is a key multifunctional virulence factor compose<em>d</em> of two <em>d</em>omains: an N-terminal <em>d</em>ouble-stran<em>d</em>e<em>d</em> RNA (<em>d</em>sRNA)-bin<em>d</em>ing <em>d</em>omain an<em>d</em> a C-terminal effector <em>d</em>omain (ED). Isolate<em>d</em> RNA-bin<em>d</em>ing an<em>d</em> effector <em>d</em>omains of NS1A both exist as homo<em>dimer</em>s in solution. Despite recent crystal structures of isolate<em>d</em> ED an<em>d</em> full-length NS1A proteins from <em>d</em>ifferent influenza virus strains, controversy remains over the actual biologically relevant ED <em>dimer</em> interface. Here, we report the biophysical properties of the NS1A ED from H3N<em>2</em> influenza A/U<em>d</em>orn/307/197<em>2</em> (U<em>d</em>) virus in solution. Several lines of evi<em>d</em>ence, inclu<em>d</em>ing (15)N NMR relaxation, NMR chemical shift perturbations, static light scattering, an<em>d</em> analytical se<em>d</em>imentation equilibrium, <em>d</em>emonstrate that U<em>d</em> NS1A ED forms a relatively weak <em>dimer</em> in solution (K(<em>d</em>) = 90 ± <em>2</em> μm), featuring a symmetric helix-helix <em>dimer</em> interface. Mutations within an<em>d</em> near this interface completely abolish <em>dimer</em>ization, whereas mutations consistent with other propose<em>d</em> ED <em>dimer</em> interfaces have no effect on <em>dimer</em> formation. In a<em>d</em><em>d</em>ition, the critical Trp-187 resi<em>d</em>ue in this interface serves as a sensitive NMR spectroscopic marker for the concentration-<em>d</em>epen<em>d</em>ent <em>dimer</em>ization of NS1A ED in solution. Finally, <em>d</em>ynamic light scattering an<em>d</em> gel shift bin<em>d</em>ing experiments <em>d</em>emonstrate that the ED interface plays a role in both the oligomerization an<em>d</em> the <em>d</em>sRNA bin<em>d</em>ing properties of the full-length NS1A protein. In particular, mutation of the critical tryptophan in the ED interface substantially re<em>d</em>uces the propensity of full-length NS1A from <em>d</em>ifferent strains to oligomerize an<em>d</em> results in a re<em>d</em>uction in <em>d</em>sRNA bin<em>d</em>ing affinity for full-length NS1A.

Venous thromboembolism (VTE) is common in patients with brain tumors, and underlying mechanisms are unclear. We hypothesized that podoplanin, a sialomucin-like glycoprotein, increases the risk of VTE in primary brain tumors via its ability to induce platelet aggregation. Immunohistochemical staining against podoplanin and intratumoral platelet aggregates was performed in brain tumor specimens of <em>2</em>13 patients (mostly high-grade gliomas [89%]) included in the Vienna Cancer and Thrombosis Study, a prospective observational cohort study of patients with newly diagnosed cancer or progressive disease aimed at identifying patients at risk of VTE. Platelet aggregation in response to primary human glioblastoma cells was investigated in vitro. <em>D</em>uring <em>2</em>-year follow-up, <em>2</em>9 (13.6%) patients developed VTE. One-hundred fifty-one tumor specimens stained positive for podoplanin (33 high expression, 47 medium expression, 71 low expression). Patients with podoplanin-positive tumors had lower peripheral blood platelet counts (P < .001) and higher <em>D</em>-<em>dimer</em> levels (P < .001). Podoplanin staining intensity was associated with increasing levels of intravascular platelet aggregates in tumor specimens (P < .001). High podoplanin expression was associated with an increased risk of VTE (hazard ratio for high vs no podoplanin expression: 5.71; 95% confidence interval, 1.5<em>2</em>-<em>2</em>1.<em>2</em>6; P =010), independent of age, sex, and tumor type. Podoplanin-positive primary glioblastoma cells induced aggregation of human platelets in vitro, which could be abrogated by an antipodoplanin antibody. In conclusion, high podoplanin expression in primary brain tumors induces platelet aggregation, correlates with hypercoagulability, and is associated with increased risk of VTE. Our data indicate novel insights into the pathogenesis of VTE in primary brain tumors.

<strong class="sub-title"> Background: </strong> The pandemic of coronavirus disease <em>2</em>019 (COVID-19) caused by severe acute respiratory syndrome coronavirus <em>2</em> (SARS-CoV-<em>2</em>) infection has made widespread impact recently. We aim to investigate the clinical characteristics of COVID-19 children with different severities and allergic status.

<strong class="sub-title"> Methods: </strong> Data extracted from the electronical medical records, including demographics, clinical manifestations, comorbidities, laboratory and immunological results and radiological images of 18<em>2</em> hospitalized COVID-19 children were summarized and analyzed.

<strong class="sub-title"> Results: </strong> The median age was 6 years old, ranging from 3 days to 15 years, and there were more boys (male-female ratio about <em>2</em>:1) within the studied 18<em>2</em> patients. Most of the children were infected by family members. Fever (43.4%) and dry cough (44.5%) were common symptoms, and gastrointestinal manifestations accounted for 11.0%, including diarrhea, abdominal discomfort and vomiting. 71.4% had abnormal chest computed tomography (CT) scan images, and typical signs of pneumonia were ground-glass opacity and local patchy shadowing on admission. Laboratory results were mostly within normal ranges, and only a small ratio of lymphopenia (3.9%) and eosinopenia (<em>2</em>9.5%) were observed. The majority (97.8%) of infected children were not severe, and <em>2</em>4 (13.<em>2</em>%) of them had asymptomatic infections. Compared to children without pneumonia(manifested as asymptomatic and acute upper respiratory infection), children with pneumonia were associated with higher percentages of the comorbidity history, symptoms of fever and cough, and increased levels of serum procalcitonin, alkaline phosphatase and serum interleukins (IL)-<em>2</em>, IL-4, IL-6, IL-10 and TNF-α.There were no differences of treatments, duration of hospitalization, time from first positive to first negative nucleic acid testing and outcomes between children with mild pneumonia and without pneumonia. All the hospitalized COVID-19 children had recovered except one death due to intussusception and sepsis. In 43 allergic children with COVID-19, allergic rhinitis (83.7%) was the major disease, followed by drug allergy, atopic dermatitis, food allergy and asthma. Demographics and clinical features were not significantly different between allergic and non-allergic groups. Allergic patients showed less increase in acute phase reactants, procalcitonin, D-dimer and aspartate aminotransferase levels compared to all patients. Immunological profiles including circulating T, B and NK lymphocyte subsets, total immunoglobulin and complement levels and serum cytokines did not show any difference in allergic and pneumonia groups. Neither eosinophil counts nor serum total immunoglobulin E (IgE) levels showed a significant correlation with other immunological measures, such as other immunoglobulins, complements, lymphocyte subsets numbers and serum cytokine levels.

<strong class="sub-title"> Conclusion: </strong> Pediatric COVID-19 patients tended to have a mild clinical course. Patients with pneumonia had higher proportion of fever and cough and increased inflammatory biomarkers than those without pneumonia. There was no difference between allergic and non-allergic COVID-19 children in disease incidence, clinical features, laboratory and immunological findings. Allergy was not a risk factor for developing and severity of SARS-CoV-<em>2</em> infection and hardly influenced the disease course of COVID-19 in children.

<strong class="sub-title"> Keywords: </strong> COVID-19; SARS-CoV-<em>2</em>; allergy; children; lymphocyte subsets; pneumonia.

YiiP is a 3<em>2</em>.9-k<em>D</em>a metal transporter foun<em>d</em> in the plasma membrane of Escherichia coli (Chao, Y., an<em>d</em> Fu, <em>D</em>. (<em>2</em>004) J. Biol. Chem. <em>2</em>79, 17173-17180). Here we report the <em>d</em>etermination of the YiiP oligomeric state in <em>d</em>etergent-lipi<em>d</em> micelles an<em>d</em> in membranes. Molecular masses of YiiP solubilize<em>d</em> with <em>d</em>o<em>d</em>ecyl-, un<em>d</em>ecyl-, <em>d</em>ecyl-, or nonyl-beta-<em>d</em>-maltosi<em>d</em>e were measure<em>d</em> <em>d</em>irectly using size-exclusion chromatography couple<em>d</em> with laser light-scattering photometry, yiel<em>d</em>ing a mass <em>d</em>istribution of YiiP homo-oligomers within a narrow range (68.0-68.8 k<em>D</em>a) that equals the pre<em>d</em>icte<em>d</em> mass of a YiiP <em>dimer</em> within experimental error. The <em>d</em>etergent-lipi<em>d</em> masses associate<em>d</em> with YiiP in the mixe<em>d</em> micelles were foun<em>d</em> to increase from 135.5 to <em>2</em>3<em>2</em>.6 k<em>D</em>a, with an apparent correlation with the alkyl chain length of the maltosi<em>d</em>e <em>d</em>etergents. Cross-linking the <em>d</em>etergent-solubilize<em>d</em> YiiP with 1-ethyl-3-[3-<em>d</em>imethylaminopropyl] carbo<em>d</em>iimi<em>d</em>e hy<em>d</em>rochlori<em>d</em>e (E<em>D</em>C) resulte<em>d</em> in a <em>dimer</em>ic cross-linke<em>d</em> pro<em>d</em>uct in an E<em>D</em>C concentration-<em>d</em>epen<em>d</em>ent manner. The oligomeric state of the purifie<em>d</em> YiiP in reconstitute<em>d</em> membranes was <em>d</em>etermine<em>d</em> by electron microscopic analysis of two-<em>d</em>imensional YiiP crystals in negative stain. A projection structure calculate<em>d</em> from measurable optical <em>d</em>iffractions to <em>2</em>5 A reveale<em>d</em> a pseu<em>d</em>o-<em>2</em>-fol<em>d</em> symmetry within a molecular boun<em>d</em>ary of approximately 75 x 40 A, in<em>d</em>icative of the presence of YiiP <em>dimers</em> in membranes. These <em>d</em>ata provi<em>d</em>e <em>d</em>irect structural evi<em>d</em>ence for a <em>dimer</em>ic association of YiiP both in <em>d</em>etergent-lipi<em>d</em> micelles an<em>d</em> in the reconstitute<em>d</em> lipi<em>d</em> bilayer. The functional relevance of the <em>dimer</em>ic association in YiiP is <em>d</em>iscusse<em>d</em>.

We used a perfused clot system to study the degradation of cross-linked fibrin. Multiangle laser light scattering showed that plasmin-mediated cleavage caused the release of noncovalently associated fibrin degradation products (F<em>D</em>Ps) with a weight-averaged molar mass (Mw) of approximately 6 x 10(6) g/mol. The Mw of F<em>D</em>Ps is dependent on ionic strength, and the Mw observed at 0.15 M NaCl resulted from the self-association of F<em>D</em>Ps having Mw of approximately 3.8 x 10(6) g/mol. Complete solubilization required the cleavage of approximately <em>2</em>5% of fragment <em>D</em>/fragment E connections, with 48% alpha-, 6<em>2</em>% beta-, and 4<em>2</em>% gamma-chains cleaved. These results showed that <em>D</em>-E cleavage cannot be explained by a random mechanism, implying cooperativity. Gel filtration and multiangle laser light scattering showed that F<em>D</em>Ps range from <em>2</em>.5 x 10(5) to 1 x 10(7) g/mol. In addition to fragment E, F<em>D</em>Ps are composed of fragments ranging from <em>2</em> x 10(5) <em>D</em>a (<em>D</em>-<em>dimer</em>, or <em>D</em><em>D</em>) to at least <em>2</em>.3 x 10(6) <em>D</em>a (<em>D</em>X8<em>D</em>). F<em>D</em>P mass distribution is consistent with a model whereby F<em>D</em>Ps bind to fibrin with affinities proportional to fragment mass. Root mean square radius analysis showed that small F<em>D</em>Ps approximate rigid rods, but this relationship breaks down as F<em>D</em>Ps size increases, suggesting that large F<em>D</em>Ps possess significant flexibility.

Previous studies from our laboratory using co-immunoprecipitation techniques suggested that the human lutropin receptor (hLHR) constitutively self-associates into <em>dimers</em>/oligomers and that agonist treatment of cells either increased hLHR <em>dimer</em>ization/oligomerization and/or stabilized hLHR <em>dimers</em>/oligomers to detergent solubilization (Tao, Y. X., Johnson, N. B., and Segaloff, <em>D</em>. L. (<em>2</em>004) J. Biol. Chem. <em>2</em>79, 5904-5914). In this study, bioluminescence resonance energy transfer (BRET(<em>2</em>)) analyses confirmed that the hLHR constitutively self-associates in living cells. After subcellular fractionation, hLHR <em>dimers</em>/oligomers were detected in both the plasma membrane and endoplasmic reticulum (ER). Further evidence supporting the constitutive formation of hLHR <em>dimer</em>/oligomers in the ER is provided by data showing homo<em>dimer</em>ization of misfolded hLHR mutants that are retained in the ER. These mutants, when co-expressed with wild-type receptor, are shown by BRET(<em>2</em>) to hetero<em>dimer</em>ize, accounting for their dominant-negative effects on cell surface receptor expression. Hormone desorption assays using intact cells demonstrate allosterism between hLHR protomers, indicating functional cell surface hLHR <em>dimers</em>. However, quantitative BRET(<em>2</em>) analyses in intact cells indicate a lack of effect of agonist on the propensity of the hLHR to <em>dimer</em>ize. Using purified plasma membranes, human chorionic gonadotropin was similarly observed to have no effect on the BRET(<em>2</em>) signal. An examination of the propensity for constitutively active and signaling inactive hLHR mutants to <em>dimer</em>ize further showed no correlation between <em>dimer</em>ization and the activation state of the hLHR. Taken altogether, our data suggest that hLHR <em>dimers</em>/oligomers are formed early in the biosynthetic pathway in the ER, are constitutively expressed on the plasma membrane, and are not affected by the activation state of the hLHR.

<em>D</em>imerization of lambda cI repressor monomers is required for high-affinity binding to bacteriophage lambda operator <em>D</em>NA and is known to involve protein-protein contacts between C-terminal domains of the repressor monomers. In order to address the importance of the C-terminal domain in mediating the oligomeric properties of <em>dimer</em>ization and cooperative binding to operator <em>D</em>NA, eight single-site mutant repressors were screened for possible deficiencies in cooperative interactions; all but one of the amino acid substitutions are located within the C-terminal domain. As a prelude to binding studies and the complete characterization of cooperativity mutants of lambda cI repressor (Burz, <em>D</em>. S., & Ackers, G. K. (1994) Biochemistry 33, 8406-8416), the thermodynamics of self-assembly of seven of these mutants was examined from 10(-11) to 10(-5) M total repressor using analytical gel chromatography. Results show that the structural perturbation accompanying single amino acid replacement does not significantly affect the monomer-<em>dimer</em> equilibrium with the exception of that accompanying replacements of serine <em>2</em><em>2</em>8; mutations at that site weaken, by <em>2</em>-4 kcal/mol, the protein-protein interactions responsible for self-association. An additional mutant repressor, Pro158->>Thr, was also examined and found to associate reversibly from monomers to a species with stoichiometry greater than <em>2</em>. All mutations increase the apparent Stokes radius of the monomeric form by <em>2</em>-4.5 A and that of <em>dimers</em> by 1 or 3 A.

High-valent iron-oxo interme<em>d</em>iates are known or believe<em>d</em> to be key oxi<em>d</em>izing species in the catalytic mechanisms of many mononuclear an<em>d</em> binuclear non-heme iron enzymes. So far only limite<em>d</em> experimental <em>d</em>ata on their electronic structures are available. In this stu<em>d</em>y we exten<em>d</em> knowle<em>d</em>ge from the experimentally well characterize<em>d</em> mononuclear Fe(IV)=O (S=1) biomimetic mo<em>d</em>el system to computational insight into the spectroscopy an<em>d</em> electronic structures of mono-an<em>d</em> binuclear high-valent iron-oxo enzyme interme<em>d</em>iates. In the mononuclear Fe(IV)=O complexes, we pre<em>d</em>ict the spectroscopy an<em>d</em> energies of the electronic transitions to be very <em>d</em>ifferent for the S=1 an<em>d</em> S=<em>2</em> spin states, but the iron-oxo bon<em>d</em>ing for both spin states to be very similar. A comparison of the S=<em>2</em> mono- an<em>d</em> binuclear high-valent iron-sites pre<em>d</em>icts similar electronic transitions. However, the bent iron-oxo bri<em>d</em>ge an<em>d</em> interactions with the secon<em>d</em> iron-center in the <em>dimer</em> shift the transitions to higher energies an<em>d</em> splits the <em>d</em>(xz/yz) orbital set. These electronic structure an<em>d</em> TD-DFT results provi<em>d</em>e a basis for un<em>d</em>erstan<em>d</em>ing the spectroscopy an<em>d</em> electronic structures of high-valent interme<em>d</em>iates in mono- an<em>d</em> binuclear non-heme iron enzymes.

A monoclonal antibo<em>d</em>y (mcAb) that recognizes an intracellular <em>d</em>omain of the major lens membrane protein in both chicken an<em>d</em> bovine lenses is <em>d</em>escribe<em>d</em>. Mice were immunize<em>d</em> with chicken lens fiber cell membranes that ha<em>d</em> been washe<em>d</em> with 7 M urea. Hybri<em>d</em>omas were screene<em>d</em> by means of enzyme-linke<em>d</em> immunosorbent assays an<em>d</em> the molecular specificities of the mcAbs were <em>d</em>etermine<em>d</em> using electrophoretic transfer proce<em>d</em>ures, "Westerns." One of these mcAbs, an IgG <em>d</em>esignate<em>d</em> B<em>2</em>, reacte<em>d</em> with a single ban<em>d</em> of <em>2</em>8,000 Mr from the chicken embryo lens (MP<em>2</em>8) an<em>d</em> the analogous <em>2</em>6,000 Mr protein in the bovine lens (MP<em>2</em>6). Monoclonal B<em>2</em> was shown to be specific for these proteins, since (a) heating in SDS cause<em>d</em> MP<em>2</em>6 to aggregate an<em>d</em> re<em>d</em>uce<em>d</em> B<em>2</em> bin<em>d</em>ing to the protein ban<em>d</em> at an Mr of <em>2</em>6,000 in Western transfer analysis; (b) apparent <em>dimers</em> were boun<em>d</em> by B<em>2</em> in Western transfers; (c) soluble protein fractions from the lens containe<em>d</em> no <em>d</em>etectable B<em>2</em> antigens; an<em>d</em> (<em>d</em>) a cyanogen bromi<em>d</em>e fragment of MP<em>2</em>6 was boun<em>d</em> by B<em>2</em>. Stu<em>d</em>ies with several proteases in<em>d</em>icate<em>d</em> that the antigenic site for B<em>2</em> resi<em>d</em>es on a <em>2</em>-k<em>d</em>, protease-sensitive region at the C-terminal en<em>d</em> of MP<em>2</em>6 an<em>d</em> MP<em>2</em>8. Evi<em>d</em>ence for B<em>2</em> bin<em>d</em>ing on the cytoplasmic si<em>d</em>e of the membrane comes from labeling stu<em>d</em>ies <em>d</em>one at the ultrastructural level. These stu<em>d</em>ies, utilizing in<em>d</em>irect metho<em>d</em>s with peroxi<em>d</em>ase an<em>d</em> colloi<em>d</em>al gol<em>d</em> markers, clearly <em>d</em>emonstrate<em>d</em> that B<em>2</em> labels two types of junctional profiles. In our calf lens membrane preparations after tannic aci<em>d</em> staining, the pre<em>d</em>ominant type (80%) measure<em>d</em> 16-18 nn thick, with the secon<em>d</em> type measuring only 1<em>2</em>-14 nm. Chick embryo lens cells that ha<em>d</em> <em>d</em>ifferentiate<em>d</em> in vitro an<em>d</em> forme<em>d</em> groups of lens fiber-like cells (terme<em>d</em> lentoi<em>d</em>s), fluoresce<em>d</em> brightly only when they ha<em>d</em> been permeabilize<em>d</em> before labeling with B<em>2</em> an<em>d</em> a fluorochrome-conjugate<em>d</em> antibo<em>d</em>y. This bin<em>d</em>ing was concentrate<em>d</em> at the plasma membranes of cells within the lentoi<em>d</em>s, even outsi<em>d</em>e areas of cell-cell contact. Surroun<em>d</em>ing epithelioi<em>d</em> cells were not staine<em>d</em>. Solubilize<em>d</em> lens cultures, examine<em>d</em> by Westerns, <em>d</em>isplaye<em>d</em> a single immunoreactive ban<em>d</em>, which co-migrate<em>d</em> with MP<em>2</em>8.

The fluorescence, F, of two dicarbocyanine dyes, diS-C3(5) and diI-C3(5), depends both on the membrane potential, E, and on the intracellular pH, pHc, or human red blood cells. Compositions of isotonic media have been devised in which the equilibrium Donnan potential, E, varies at constant pHc and in which pHc varies at constant E. Dye fluorescence measurements in these suspensions yield calibrations of +1.7 % <em>delta</em> F/mV for diS-C3(5) and +0.6 % <em>delta</em> F/mV for diI-C3 (5). While pHo does not affect F of either dye, changes in pHc of 0.1 unit at constant E cause changes of F equivalent to those induced by <em>2</em>--3mV. Based on these results, a method is given for estimating changes in E from dye fluorescence in experiments in which E and pHc co-vary. The relation of F to E also depends in a complex way on the type and concentration of cells and dye, and the wavelengths employed. The equilibrium calibration of dye fluorescence, when applied to diffusion potentials induced by 1 microM valinomycin, yields a value for the permeability ratio, PK.VAL/PCl, of <em>2</em>0 +/- 5, in agreement with previous estimates by other methods. The calibration of F is identical both for diffusion potentials and for equilibrium potentials, implying that diC-C3(5) responds to changes in voltage independently of ionic fluxes across the red cell membrane. Changes in the absorption spectra of dye in the presence of red cells in response to changes in E show that formation of nonfluorescent <em>dimers</em> contributes to fluorescence quenching of diS-C3(5). In contrast, only a hydrophobic interaction of dye monomers need be considered for diI-C3(5), indicating the occurrence of a simpler mechanism of fluorescence quenching.

Haemostatic changes in 16 patients with Crohn's disease were studied from active disease into clinical remission and beyond. Elevated concentrations of fibrinopeptide A (FpA) and prothrombin fragments F1 + <em>2</em> (F1 + <em>2</em>) were found at times of both active (FpA median 3.<em>2</em>, range [0.3-40] ng/ml and F1 + <em>2</em> median <em>2</em>.3, range [0.3-18] nm/l) and inactive disease (FpA median <em>2</em>, range [0.4-40] ng/ml and F1 + <em>2</em> median 1.3, range [0.<em>2</em>-<em>2</em>0) nm/l]. We also measured the physiological inhibitors of coagulation and fibrinolysis; there was no significant difference in the levels of antithrombin III, protein C or the Exner ratio between active and inactive disease. Free protein S levels were significantly lower in active disease (median 34, range 9-54 U/dl) than in remission (median 40, range 1<em>2</em>-65 U/dl). Plasminogen activator inhibitor type 1 (PAI-1) was significantly raised in remission (median 11, range 3-3<em>2</em> ng/ml) when compared to active disease (median 7, range 3-4<em>2</em> ng/ml). The <em>D</em>-<em>dimer</em> correlated significantly with fibrinopeptide A (P < 0.001), suggesting reactive fibrinolysis in some patients. Most (35/5<em>2</em>, 67%) samples showed evidence of persistent haemostatic activation (elevated FpA and/or F1 + <em>2</em>) during phases of apparent clinical remission in Crohn's disease, a factor that is not reflected by clinical activity scores. This study supports the hypothesis that coagulation is activated in the mesenteric vasculature of patients with Crohn's disease.

Mithramycin (MTH) is a <em>D</em>NA-bin<em>d</em>ing antitumor agent containing A-B <em>d</em>isacchari<em>d</em>e an<em>d</em> C-<em>D</em>-E trisacchari<em>d</em>e segments projecting from opposite en<em>d</em>s of an aglycone chromophore. We have previously reporte<em>d</em> on the solution structure of the MTH-<em>D</em>NA 6-mer complex base<em>d</em> on a combine<em>d</em> NMR an<em>d</em> molecular <em>d</em>ynamics stu<em>d</em>y. This stu<em>d</em>y establishe<em>d</em> that the Mg(<em>2</em>+)-coor<em>d</em>inate<em>d</em> mithramycin <em>dimer</em> boun<em>d</em> to a wi<em>d</em>ene<em>d</em> minor groove centere<em>d</em> about the sequence-specific (G-C).(G-C) site an<em>d</em> that the C-<em>D</em>-E trisacchari<em>d</em>e segments from in<em>d</em>ivi<em>d</em>ual monomers were <em>d</em>irecte<em>d</em> towar<em>d</em>s opposite en<em>d</em>s of the helix spanning a six base-pair segment. This research is now exten<em>d</em>e<em>d</em> to the bin<em>d</em>ing of mithramycin <em>dimers</em> to partially overlapping sites on the self-complementary <em>d</em>(T-A-G-C-T-A-G-C-T-A) 10-mer <em>d</em>uplex. The six base-pair mithramycin <em>dimer</em> footprint centere<em>d</em> about (G-C).(G-C) steps shoul<em>d</em> result in a potential steric clash in the center of the helix involving the inwar<em>d</em>ly pointing E-sugars of the pair of mithramycin <em>dimers</em> boun<em>d</em> to the <em>D</em>NA 10-mer <em>d</em>uplex. The MTH-<em>d</em>(T-A-G-C-T-A-G-C-T-A) complex (two MTH <em>dimers</em> per <em>d</em>uplex) yiel<em>d</em>s narrow an<em>d</em> well-resolve<em>d</em> NMR spectra, which have been assigne<em>d</em> to i<em>d</em>entify intramolecular an<em>d</em> intermolecular nuclear Overhauser enhancement (NOE) connectivities in the complex. The solution structure of the MTH-<em>D</em>NA 10-mer complex base<em>d</em> on <em>d</em>istance-restraine<em>d</em> molecular <em>d</em>ynamics calculations has <em>d</em>efine<em>d</em> the conformation of the <em>d</em>rug an<em>d</em> the <em>D</em>NA necessary for accommo<em>d</em>ation of the pair of mithramycin <em>dimers</em> on the <em>D</em>NA 10-mer helix. Specifically, the inwar<em>d</em>ly pointing E-sugars retain their face-<em>d</em>own alignment towar<em>d</em>s the floor of the minor groove an<em>d</em> occupy a<em>d</em>jacent bin<em>d</em>ing sites in the center of the <em>d</em>uplex. This is achieve<em>d</em>, in part, through torsion angle <em>d</em>ifferences in the glycosi<em>d</em>ic linkage bon<em>d</em>s along the length of the inwar<em>d</em>ly pointing aglycone-C-<em>D</em>-E trisacchari<em>d</em>e segment relative to its outwar<em>d</em>ly pointing aglycone-C-<em>D</em>-E trisacchari<em>d</em>e counterpart in the complex. In a<em>d</em><em>d</em>ition, a pronounce<em>d</em> kink at the central (T-A).(T-A) step opens the minor groove an<em>d</em> generates a<em>d</em><em>d</em>itional space to accommo<em>d</em>ate the inwar<em>d</em>ly pointing E-sugars at a<em>d</em>jacent sites in the MTH-<em>D</em>NA 10-mer complex. These stu<em>d</em>ies establish conformational plasticity in the C-<em>D</em>-E trisacchari<em>d</em>e segment of the mithramycin <em>dimer</em> an<em>d</em> <em>d</em>eformability of the <em>D</em>NA helix allowing mithramycin <em>dimers</em> to bin<em>d</em> to partially overlapping minor groove sites on the <em>D</em>NA helix.

The monomeric form of the acetylcholine receptor from torpedo is composed of five, membrane-spanning chains with the stoichiometry alpha <em>2</em> beta gamma <em>delta</em>. The native receptor is predominantly a <em>dimer</em> cross-linked by a disulfide bridge between <em>delta</em> chains. We reduced native <em>dimer</em> to monomer and generated a different <em>dimer</em> by diamide-induced disulfide formation specifically between beta chains. Purified beta-beta cross-linked <em>dimer</em>, when adsorbed to a carbon film and negatively stained, appears in the electron microscope as two contiguous disks, frequently with central, stain-filled pits; i.e. it looks like native receptor in situ viewed normal to the plane of the membrane. We take the region of closest approach of the disks to mark the portions of the beta chains involved in the cross-link. In addition, we tagged the acetylcholine binding sites (one on each alpha chain) for electron microscopic identification, using a complex of monobiotinylated cobratoxin and avidin. Based on the locations of avidins bound to the beta-beta cross-linked <em>dimer</em>, the two toxin binding sites/monomer appear to be separated on the average by 110 degrees, as measured between lines from the center of the monomer to the centers of the avidins. One toxin binding site appears close to the beta-beta cross-link and the other close to the end of the monomer opposite to the cross-link; these locations are similar to the locations of the toxin binding sites relative to the <em>delta</em>-<em>delta</em> cross-link in native <em>dimer</em>. On the assumptions that the chains are compact units and are arranged in a unique order around the central pit, we interpret these results as indicating that the alpha chains are not contiguous and that neither the beta chain nor the <em>delta</em> chain lies between them. Therefore, the arrangement of the chains most easily reconciled with our assumptions and observations is alpha gamma alpha beta <em>delta</em>.

Cytidine deaminases (C<em>D</em>A, EC 3.5.4.5) are zinc-containing enzymes in the pyrimidine salvage pathway that catalyze the formation of uridine and deoxyuridine from cytidine and deoxycytidine, respectively. Two different classes have been identified in the C<em>D</em>A family, a homo<em>dimer</em>ic form (<em>D</em>-C<em>D</em>A) with two zinc ions per <em>dimer</em> and a homotetrameric form (T-C<em>D</em>A) with four zinc ions per tetramer. We have determined the first structure of a T-C<em>D</em>A from Bacillus subtilis. The active form of T-C<em>D</em>A is assembled of four identical subunits with one active site apiece. The subunit of <em>D</em>-C<em>D</em>A is composed of two domains each exhibiting the same fold as the T-C<em>D</em>A subunits, but only one of them contains zinc in the active site. The similarity results in a conserved structural core in the two C<em>D</em>A forms. An intriguing difference between the two C<em>D</em>A structures is the zinc coordinating residues found at the N-terminal of two alpha-helices: three cysteine residues in the tetrameric form and two cysteine residues and one histidine residue in the <em>dimer</em>ic form. The role of the zinc ion is to activate a water molecule and thereby generate a hydroxide ion. How the zinc ion in T-C<em>D</em>A surrounded with three negatively charged residues can create a similar activity of T-C<em>D</em>A compared to <em>D</em>-C<em>D</em>A has been an enigma. However, the structure of T-C<em>D</em>A reveals that the negative charge caused by the three ligands is partly neutralized by (1) an arginine residue hydrogen-bonded to two of the cysteine residues and (<em>2</em>) the dipoles of two alpha-helices.

OBJECTIVE

This study was designed to determine whether novel cardiovascular disease (CVD) risk factors explain the high prevalence of peripheral arterial disease (PAD) among African Americans.

BACKGROUND

Compared with Caucasians, African Americans have higher prevalence of PAD, an association that is not explained by traditional CVD risk factors. The degree to which novel CVD risk markers may explain the higher prevalence is uncertain.

METHODS

A nested case-control study within the San <em>D</em>iego Population Study was performed. The study evaluated 104 persons with PA<em>D</em> and 164 age- and gender-matched control subjects who were employees of a large public university and participated in a peripheral artery and venous disease study. Nine novel CV<em>D</em> risk factors (homocysteine, lipoprotein (a), C-reactive protein, fibrinogen, tumor necrosis factor-alpha, von Willebrand factor, prothrombin fragment 1-<em>2</em>, <em>D</em>-<em>dimer</em>, and plasmin antiplasmin) were measured. Multivariable logistic regression evaluated whether these novel factors attenuated the association of African-American race and PA<em>D</em> and whether there was differential ethnic susceptibility to the novel factors.

RESULTS

African Americans had 3-fold higher odds of PA<em>D</em> in age- and gender-matched models (odds ratio [OR] 3.1; 95% confidence interval [CI] 1.5 to 6.4; p < 0.01), an association that was modestly attenuated by adjustment for traditional (OR <em>2</em>.4; 95% CI 0.9 to 6.1; p = 0.06) and novel CV<em>D</em> risk markers (OR 1.9; 95% CI 0.7 to 4.7; p = 0.18). Among the novel factors, the attenuation was primarily due to fibrinogen and lipoprotein (a). No interactions by novel CV<em>D</em> risk markers (both p values for interaction>> or =0.<em>2</em>4) were observed.

CONCLUSIONS

Traditional and novel CVD risk factors only partially explain the higher prevalence of PAD among African Americans.

The factor for inversion stimulation (FIS) binds as a homo<em>dimer</em>ic molecule to a loose 15 nucleotide consensus sequence in <em>D</em>NA. It stimulates <em>D</em>NA-related processes, such as <em>D</em>NA inversion and excision, it activates transcription of tRNA and rRNA genes and it regulates its own synthesis. FIS crystallizes as a homo<em>dimer</em>, with <em>2</em> x 98 amino acid residues in the asymmetric unit. The crystal structure was determined with multiple isomorphous replacement and refined to an R-factor of 19.<em>2</em>% against all the 1<em>2</em>,719 X-ray data (no sigma-cutoff) extending to <em>2</em>.0 A resolution. The two monomers are related by a non-crystallographic dyad axis. The structure of the <em>dimer</em> is modular, with the first <em>2</em>3 amino acid residues in molecule M1 and the first <em>2</em>4 in molecule M<em>2</em> disordered and not "seen" in the electron density. The polypeptide folds into four alpha-helices, with alpha A, alpha A' (amino acid residues <em>2</em>6 to 40) and alpha B, alpha B' (49 to 69) forming the core of the FIS <em>dimer</em>, which is stabilized by hydrophobic forces. To the core are attached "classical" helix-turn-helix motifs, alpha C, alpha <em>D</em> (73 to 81 and 84 to 94) and alpha C', alpha <em>D</em>'. The connections linking the helices are structured by two beta-turns for alpha A/alpha B, and alpha C1 type extensions are observed at the C termini of helices alpha B, alpha C and alpha <em>D</em>. Helices alpha <em>D</em> and alpha <em>D</em>' contain <em>2</em> x 6 positive charges; they are separated by <em>2</em>4 A and can bind adjacent major grooves in B-type <em>D</em>NA if it is bent 90 degrees. The modular structure of FIS is also reflected by mutation experiments; mutations in the N-terminal part and alpha A interfere with FIS binding to invertases, and mutations in the helix-turn-helix motif interfere with <em>D</em>NA binding.

Potent an<em>d</em> selective inhibitors of in<em>d</em>ucible nitric oxi<em>d</em>e synthase (iNOS) (EC ) were i<em>d</em>entifie<em>d</em> in an enco<em>d</em>e<em>d</em> combinatorial chemical library that blocke<em>d</em> human iNOS <em>dimer</em>ization, an<em>d</em> thereby NO pro<em>d</em>uction. In a cell-base<em>d</em> iNOS assay (A-17<em>2</em> astrocytoma cells) the inhibitors ha<em>d</em> low-nanomolar IC(50) values an<em>d</em> thus were >1,000-fol<em>d</em> more potent than the substrate-base<em>d</em> <em>d</em>irect iNOS inhibitors 1400W an<em>d</em> N-methyl-l-arginine. Biochemical stu<em>d</em>ies confirme<em>d</em> that inhibitors cause<em>d</em> accumulation of iNOS monomers in mouse macrophage RAW <em>2</em>64.7 cells. High affinity (K(<em>d</em>) approximately 3 nM) of inhibitors for isolate<em>d</em> iNOS monomers was confirme<em>d</em> by using a ra<em>d</em>ioligan<em>d</em> bin<em>d</em>ing assay. Inhibitors were >1,000-fol<em>d</em> selective for iNOS versus en<em>d</em>othelial NOS <em>dimer</em>ization in a cell-base<em>d</em> assay. The crystal structure of inhibitor boun<em>d</em> to the monomeric iNOS oxygenase <em>d</em>omain reveale<em>d</em> inhibitor-heme coor<em>d</em>ination an<em>d</em> substantial perturbation of the substrate bin<em>d</em>ing site an<em>d</em> the <em>dimer</em>ization interface, in<em>d</em>icating that this small molecule acts by allosterically <em>d</em>isrupting protein-protein interactions at the <em>dimer</em> interface. These results provi<em>d</em>e a mechanism-base<em>d</em> approach to highly selective iNOS inhibition. Inhibitors were active in vivo, with ED(50) values of (<em>2</em> mg/kg in a rat mo<em>d</em>el of en<em>d</em>otoxin-in<em>d</em>uce<em>d</em> systemic iNOS in<em>d</em>uction. Thus, this class of <em>dimer</em>ization inhibitors has broa<em>d</em> therapeutic potential in iNOS-me<em>d</em>iate<em>d</em> pathologies.

Oligo<em>d</em>eoxyribonucleosi<em>d</em>e methylphosphonates of <em>d</em>efine<em>d</em> sequence of the type <em>d</em>-Np(NP)nN, where n is 6-13, are rea<em>d</em>ily prepare<em>d</em> on insoluble polystyrene supports by use of protecte<em>d</em> 5'-(<em>d</em>imethoxytrityl)<em>d</em>eoxyribonucleosi<em>d</em>e 3'-(methylphosphonic imi<em>d</em>azoli<em>d</em>es) as synthetic interme<em>d</em>iates. The imi<em>d</em>azoli<em>d</em>es are prepare<em>d</em> in situ by reaction of protecte<em>d</em> 5'-(<em>d</em>imethoxytrityl)<em>d</em>eoxyribonucleosi<em>d</em>e with methylphosphonic bis(imi<em>d</em>azoli<em>d</em>e) an<em>d</em> can be stores in the reaction solution for up to <em>2</em> weeks at 4 <em>d</em>egrees C with no loss in activity. The con<em>d</em>ensation reaction is accelerate<em>d</em> by the presence of tetrazole, which appears to act as an aci<em>d</em> catalyst. The half-life for <em>dimer</em> formation on the polystyrene support is 5 min, an<em>d</em> the reaction is 95% complete after 60 min. Although similar kinetics are observe<em>d</em> when controlle<em>d</em> pore glass is use<em>d</em> as the support, the extent of the reaction <em>d</em>oes not go beyon<em>d</em> 78%, even after prolonge<em>d</em> incubation. In or<em>d</em>er to simplify purification an<em>d</em> sequence analysis of the oligomer, the 5'-terminal nucleosi<em>d</em>e unit is linke<em>d</em> via a phospho<em>d</em>iester bon<em>d</em>. This linkage may be intro<em>d</em>uce<em>d</em> by either an o-chlorophenyl phosphotriester metho<em>d</em> or a cyanoethyl phosphorami<em>d</em>ite metho<em>d</em>. The latter proce<em>d</em>ure simplifies the <em>d</em>eprotection step, since the cyanoethyl group is rea<em>d</em>ily cleave<em>d</em> by ethylene<em>d</em>iamine, which also removes the base protecting groups an<em>d</em> cleaves the oligomer from the support. The singly charge<em>d</em> oligomers are easily purifie<em>d</em> by affinity chromatography on DEAE-cellulose. The chain lengths of the oligomers were confirme<em>d</em> after 5'-en<em>d</em> labeling with polynucleoti<em>d</em>e kinase by partial hy<em>d</em>rolysis of the methylphosphonate linkages with 1 M aqueous piperi<em>d</em>ine followe<em>d</em> by polyacrylami<em>d</em>e gel electrophoresis of the hy<em>d</em>rolysate.(ABSTRACT TRUNCATED AT <em>2</em>50 WORDS)

On March 11, <em>2</em>0<em>2</em>0, the World Health Organization declared its assessment of COVI<em>D</em>-19 as a global pandemic. However, specific anti SARS-CoV-<em>2</em> drugs are still under development, and patients are managed by multiple complementary treatments. We performed a retrospective analysis to compare and evaluate the effect of low molecular weight heparin (LMWH) treatment on disease progression. For this purpose, the clinical records and laboratory indicators were extracted from electronic medical records of forty-two patients with COVI<em>D</em>-19 (twenty-one of whom were treated with LMWH, and twenty-one without LMWH) hospitalized (Union Hospital of Huazhong University of Science and Technology) from February 1 to March 15, <em>2</em>0<em>2</em>0. Changes in the percentage of lymphocytes before and after LMWH treatment were significantly different from those in the control group (p=0.011). Likewise, changes in the levels of <em>D</em>-<em>dimer</em> and fibrinogen degradation products (F<em>D</em>P) in the LMWH group before and after treatment were significantly different from those in the control group (p=0.035). Remarkably, IL-6 levels were significantly reduced after LMWH treatment (p=0.006), indicating that, besides other beneficial properties, LMWH may exert an anti-inflammatory effect and attenuate in part the 'cytokine storm' induced by the virus. Our results support the use of LMWH as a potential therapeutic drug for the treatment of COVI<em>D</em>-19, paving the way for a subsequent well-controlled clinical study.

Keywords: COVID-19; Cytokine Storm; IL-6; LMWH; Lymphocytes%.

<AbstractText><em>D</em>escribe characteristics, daily care and outcomes of patients with coronavirus disease <em>2</em>019 (COVI<em>D</em>-19) acute respiratory distress syndrome (AR<em>D</em>S).</AbstractText><AbstractText>Case series of 73 patients.</AbstractText><AbstractText>Large tertiary hospital in Milan.</AbstractText><AbstractText>Mechanically ventilated patients with confirmed COVI<em>D</em>-19 admitted to the intensive care unit (ICU) between <em>2</em>0 February and <em>2</em> April <em>2</em>0<em>2</em>0.</AbstractText><AbstractText><em>D</em>emographic and daily clinical data were collected to identify predictors of early mortality.</AbstractText><p><div><b>Results</b></div>Of the 73 patients included in the study, most were male (83.6%), the median age was 61 years (interquartile range [IQR], 54-69 years), and hypertension affected 5<em>2</em>.9% of patients. Lymphocytopenia (median, 0.77 x 10³ per mm³ ; IQR, 0.58-1.00 x 10³ per mm³), hyperinflammation with C-reactive protein (median, 184.5 mg/dL; IQR, 108.<em>2</em>-<em>2</em>69.1 mg/dL) and pro-coagulant status with <em>D</em>-<em>dimer</em> (median, 10.1 μg/m; IQR, 5.0-<em>2</em>3.8 μg/m) were present. Median tidal volume was 6.7 mL/kg (IQR, 6.0-7.5 mL/kg), and median positive end-expiratory pressure was 1<em>2</em> cmH_<em>2</em>O (IQR, 10-14 cmH_<em>2</em>O). In the first 3 days, prone positioning (1<em>2</em>-16 h) was used in 63.8% of patients and extracorporeal membrane oxygenation in five patients (6.8%). After a median follow-up of 19.0 days (IQR, 15.0-<em>2</em>7.0 days), 17 patients (<em>2</em>3.3%) had died, <em>2</em>3 (31.5%) had been discharged from the ICU, and 33 (45.<em>2</em>%) were receiving invasive mechanical ventilation in the ICU. Older age (odds ratio [OR], 1.1<em>2</em>; 95% CI, 1.04-1.<em>2</em><em>2</em>; <i>P</i> = 0.004) and hypertension (OR, 6.15; 95% CI, 1.75-<em>2</em>9.11; <i>P</i> = 0.009) were associated with mortality, while early improvement in arterial partial pressure of oxygen (PaO_<em>2</em>) to fraction of inspired oxygen (FiO_<em>2</em>) ratio was associated with being discharged alive from the ICU (<i>P</i> = 0.00<em>2</em> for interaction).</p><AbstractText><em>D</em>espite multiple advanced critical care interventions, COVI<em>D</em>-19 AR<em>D</em>S was associated with prolonged ventilation and high short term mortality. Older age and pre-admission hypertension were key mortality risk factors.</AbstractText><AbstractText>ClinicalTrials.gov identifier: NCT04318366.</AbstractText>

OBJECTIVE

Laparoscopic gastric bypass (GBP) induces a postoperative hypercoagulable state that is similar or reduced compared with open GBP.

METHODS

University hospital.

METHODS

Between May 1999 and June 2000, 70 patients were randomly assigned to laparoscopic (n = 36) or open (n = 34) GBP. Deep venous thrombosis (DVT) prophylaxis consisted of antiembolism stockings and sequential pneumatic compression devices.

METHODS

Plasminogen, thrombin-antithrombin complex (TAT), prothrombin fragment 1.2 (F1.2), fibrinogen, D-dimer, antithrombin III (AT), and protein C levels were measured at baseline and at 1, 24, 48, and 72 hours postoperatively. A venous duplex examination of both lower extremities was performed preoperatively and between the third and fifth day postoperatively.

RESULTS

The 2 groups were similar in age, weight, and body mass index. Plasminogen levels decreased, and TAT, F1.2, and fibrinogen levels increased after laparoscopic and open GBP. There was no significant difference in these levels between groups. D-dimer levels increased in both groups, but the levels were significantly higher after open GBP than after laparoscopic GBP (P<.01). Antithrombin III and protein C levels decreased in both groups. The reduction of AT (at 1 hour) and protein C (at 72 hours) was significantly less after laparoscopic GBP than after open GBP (P<.05). Postoperative venous duplex examination revealed DVT in 1 (2.9%) of 34 patients after open GBP but in none of 36 patients after laparoscopic GBP. One patient developed pulmonary embolism after open GBP.

CONCLUSIONS

Laparoscopic GBP induces a hypercoagulable state similar to that of open GBP. Our findings suggest that DVT prophylaxis should be used during laparoscopic GBP as in open GBP.