BACKGROUND

Defective thrombolysis, a thrombotic risk factor, can be attributed to the formation of a compact clot poorly accessible to fibrinolytic enzymes. Venous thrombi, rich in red blood cells (RBCs), and arterial thrombi containing various amounts of RBCS, plasma and whole blood (WB) clot permeability and degradability were compared. The effect of rivaroxaban, a potent direct factor Xa inhibitor, was also evaluated.

METHODS

Fibrin permeability was determined by flow measurement through the clot. Clot degradability was evaluated by the amount of D-dimer generated by clot perfusion with plasminogen and tissue plasminogen activator. Fibrin clot structure was assessed by confocal microscopy.

RESULTS

WB clot permeability (KS) and degradability were 6.7- and 38-fold lower, respectively, compared with plasma clots. This is attributed to 1) occlusion of fibrin pores by RBCs and 2) a consistent increase in thrombin generation due to platelets and RBCs inducing formation of a tighter clot. Rivaroxaban added to plasma or WB before clotting, in reducing thrombin generation, led to the formation of a looser clot that is more degradable by fibrinolytic enzymes. Permeability and degradability of whole blood clots formed in the presence of rivaroxaban were very similar to those of plasma clots.

CONCLUSIONS

The resistance to fibrinolysis of WB clots was reduced considerably when clots were formed with rivaroxaban. These results may have implications for the development of antithrombotic agents.

The aim of this study was to identify the changes of hematologic and immunological parameters in COVI<em>D</em>-19 patients. We collected and analyzed the data of 117 patients who were laboratory confirmed as SARS-CoV-<em>2</em> infection. The cases were divided into regular group, severe group and critically ill group according to the sixth edition scheme for COVI<em>D</em>-19 diagnosis and treatment of China. The laboratory tests included blood routine, cellular and humoral immunity indices, biochemical detections and inflammatory biomarker. Compared with regular patients, severe and critically ill patients had significantly lower lymphocyte count (p < 0.01), decreased red blood cell and hemoglobin (p < 0.01), low levels of immunoglobulin G (p < 0.05) and significantly higher in <em>D</em>-<em>dimer</em> (p < 0.0001), fibrinogen (p < 0.01), white blood cell count (p < 0.01), neutrophil count (p < 0.0001), interleukin-6 (p < 0.05), C-reactive protein (p < 0.01), procalcitonin (p < 0.01), erythrocyte sedimentation rate (p < 0.05), ferritin (p < 0.01) and lactate dehydrogenase (p < 0.0001). The specific immunoglobulin G antibodies to the SARS-CoV-<em>2</em> in severe and critically ill patients were significantly lower than that in regular patients (p < 0.05). Our findings suggest that the lymphocyte counts, red blood cell counts and the immunoglobulin G antibodies of COVI<em>D</em>-19 patients were impaired to varying degrees and the blood was in a state of hypercoagulation, which were more obvious in critically ill patients.

<strong class="sub-title"> Keywords: </strong> COVI<em>D</em>-19; Hematological parameters; Immunological parameters; SARS-CoV-<em>2</em>.

BACKGROUND

Registries are essential to obtain information on the whole spectrum of patients with pulmonary embolism (PE). The aim of the Italian Pulmonary Embolism Registry (IPER) is to report on demographics, clinical features, management, and outcomes of patients diagnosed with PE in everyday clinical practice.

METHODS

Patients with confirmed acute PE were enrolled in a web-based registry, in Cardiology, Emergency or Internal Medicine Departments in 47 hospitals in Italy.

RESULTS

Overall, 1716 patients were included, mean age 70 ± 15 years, (14% of the patients were <50 and 43% >75 year old); 57% of female gender and 11.7% hemodynamically unstable at presentation/diagnosis. <em>D</em>-<em>dimer</em> was performed in 1358 patients (80%). Computerized tomographic pulmonary angiogram (CT) was used for diagnosis in the majority of the patients (8<em>2</em>.1%), followed by perfusion lung scan (8.6%). Thrombolytic agents were used in 185 (10.8%) patients, percutaneous thrombectomy in 14 (0.8%) and surgery in <em>2</em> (0.1%). One hundred sixteen patients died while in-hospital (6.7%), 68 (3.9%) due to PE. <em>D</em>eath or clinical deterioration occurred in 138 patients (8.0%). All-cause mortality was 31.8% in hemodynamically unstable patients and 3.4% in hemodynamically stable patients; the corresponding PE-related deaths were <em>2</em>3.3% and 1.4% respectively. Age >75 (HR 1.50, 95% CI 1.01-<em>2</em>.<em>2</em>5), immobilization>> 3 days before diagnosis of PE (HR <em>2</em>.54, 95% CI 1.7<em>2</em>-3.77) and hemodynamic impairment (HR 6.38, 95% CI 4.<em>2</em>6-9.57) were independent predictors for in-hospital death.

CONCLUSIONS

Patients with PE have a considerable risk of death during the hospital stay, PE being the most common cause of early mortality.

Background: Disease severity and mortality rates due to COVID-19 infection are greater in the elderly and chronically ill patients, populations at high risk for vitamin D deficiency. Vitamin D plays an important role in immune function and inflammation. This systematic review and meta-analysis assesses the impact of vitamin D status and supplementation on COVID-19 related mortality and health outcomes.

Methods: We searched four databases until December 18th 2020, and trial registries until January 20th 2021. Two reviewers screened the studies, collected data, assessed the risk of bias, and graded the evidence for each outcome across studies, independently and in duplicate. Pre-specified outcomes of interest were mortality, ICU admission, invasive and non-invasive ventilation, hospitalization, time of hospital stay, disease severity and SARS-CoV-2 positivity. We only included data from peer-reviewed articles in our primary analyses.

Results: We identified 31 peer-reviewed observational studies. In our primary analysis, there was a positive trend between serum 25(OH)D level < 20 ng/ml and an increased risk of mortality, ICU admission, invasive ventilation, non-invasive ventilation or SARS-CoV-2 positivity. However, these associations were not statistically significant. Mean 25(OH)D levels was 5.9 ng/ml (95%CI [-9.5, -2.3]) significantly lower in COVID-19 positive, compared to negative patients. The certainty of the evidence was very low. We identified 32 clinical trial protocols, but only three have published results to-date. The trials administer vitamin D doses of 357 to 60,000 IU/d, from one week to 12 months. Eight megatrials investigate the efficacy of vitamin D in outpatient populations. A pilot trial revealed a significant decrease in ICU admission with calcifediol, compared to placebo (OR = 0.003), but the certainty of the evidence was unclear. Another small trial showed that supplementation with cholecalciferol, 60,000 IU/d, decreased fibrinogen levels, but did not have an effect on D-dimer, procalcitonin and CRP levels, compared to placebo. The third trial did not find any effect of vitamin D supplementation on COVID-19 related health outcomes.

Conclusion: While the available evidence to-date, from largely poor-quality observational studies, may be viewed as showing a trend for an association between low serum 25(OH)D levels and COVID-19 related health outcomes, this relationship was not found to be statistically significant. Calcifediol supplementation may have a protective effect on COVID-19 related ICU admissions. The current use of high doses of vitamin D in COVID-19 patients is not based on solid evidence. It awaits results from ongoing trials to determine the efficacy, desirable doses, and safety, of vitamin D supplementation to prevent and treat COVID-19 related health outcomes.

Keywords: COVID-19; Hospitalization; ICU admission; Mortality; Vitamin D.

The acute respiratory illnesses caused by severe acquired respiratory syndrome corona Virus-<em>2</em> (SARS-CoV-<em>2</em>) is a global health emergency, involving more than 8.6 million people worldwide with more than 450,000 deaths. Among the clinical manifestations of COVID-19, the disease that results from SARS-CoV-<em>2</em> infection in humans, a prominent feature is a pro-thrombotic derangement of the hemostatic system, possibly representing a peculiar clinicopathologic manifestation of viral sepsis. The severity of the derangement of coagulation parameters in COVID-19 patients has been associated with a poor prognosis, and the use of low molecular weight heparin (LMWH) at doses registered for prevention of venous thromboembolism (VTE) has been endorsed by the World Health Organization and by Several Scientific societies. However, some relevant issues on the relationships between COVID-19, coagulopathy and VTE have yet to be fully elucidated. This review is particularly focused on four clinical questions: What is the incidence of VTE in COVID-19 patients? How do we frame the COVID-19 associated coagulopathy? Which role, if any, do antiphospolipid antibodies have? How do we tackle COVID-19 coagulopathy? In the complex scenario of an overwhelming pandemic, most everyday clinical decisions have to be taken without delay, although not yet supported by a sound scientific evidence. This review discusses the most recent findings of basic and clinical research about the COVID-associated coagulopathy, to foster a more thorough knowledge of the mechanisms underlying this compelling disease.

Keywords: Antiphospholipid antibodies; COVID-19; Coagulopathy; D-dimer; Disseminated intravascular coagulation; Low molecular weight heparin; Sepsis-induced coagulopathy; Unfractionated heparin; Venous thromboembolism.

The solution structures of the oligo<em>d</em>eoxynucleoti<em>d</em>es <em>d</em>(CCCGTTTCC) an<em>d</em> <em>d</em>(TCCCGTTTCCA) have been <em>d</em>etermine<em>d</em> by two-<em>d</em>imensional NMR spectroscopy. These oligomers are part of a DNA box in human centromeric alpha satellite targete<em>d</em> by the centromere protein B (CENP-B). Both CENP-B an<em>d</em> its recognition box in alphoi<em>d</em> DNA are conserve<em>d</em> in mammals, suggesting an important biological role. At aci<em>d</em>ic pH, <em>d</em>(CCCGTTTCC), <em>d</em>(TCCCGTTTCCA) an<em>d</em> the full <em>d</em>(TCCCGTTTCCAACGAAG) CENP-B box stran<em>d</em> all fol<em>d</em> an<em>d</em> <em>dimer</em>ize in solution forming a stable bimolecular structure containing two GTTT hairpin loops that interact through a novel T : G : G : T tetra<em>d</em>. The stem region of the <em>dimer</em> is a four-stran<em>d</em>e<em>d</em> intercalate<em>d</em> motif in which the hairpin monomers are parallel an<em>d</em> hel<em>d</em> together by C : C+ hy<em>d</em>rogen-bon<em>d</em>ing an<em>d</em> intercalation. The loops are at the same en<em>d</em> of the <em>dimer</em> an<em>d</em> lie across the narrow grooves of the tetraplex. They are remarkably structure<em>d</em> an<em>d</em> stabilize<em>d</em> by base-base cross-stacking, sugar-base stacking, an<em>d</em> parallel G:G an<em>d</em> antiparallel G:T pairing. In the <em>d</em>(TCCCGTTTCCA)<em>2</em> structure, the intercalate<em>d</em> motif is continue<em>d</em> at the other en<em>d</em> of the <em>dimer</em> with unpaire<em>d</em> but stacke<em>d</em> a<em>d</em>enine an<em>d</em> thymine bases. The possible biological implications of these structures are <em>d</em>iscusse<em>d</em>.

Background: The effectual immune response is crucial to defeat viral infections. However, exuberant immune response with features of macrophage activation syndrome (MAS) lead detrimental consequences in COVID-19 patients. Interleukin (IL)-18 is one of the leading cytokines in MAS which has not been studied in COVID-19.

Objective: To investigate the association of IL-18 with the other inflammatory markers and disease severity in COVID-19 for predicting disease prognosis.

<strong class="sub-title"> Metho<em>d</em>s: </strong> Patients with COVID-19 who ha<em>d</em> confirme<em>d</em> <em>d</em>iagnosis with SARS-CoV-<em>2</em> nucleic aci<em>d</em> RT-PCR were enrolle<em>d</em> into the stu<em>d</em>y. Data on <em>d</em>emographic an<em>d</em> clinical characteristics, an<em>d</em> laboratory values of CRP, ferritin, <em>d</em>-<em>dimer</em> an<em>d</em> procalcitonin were measure<em>d</em> on a<em>d</em>mission. Patients were followe<em>d</em> up prospectively with a stan<em>d</em>ar<em>d</em>ize<em>d</em> approach until hospital <em>d</em>ischarge or <em>d</em>eath. In<em>d</em>ivi<em>d</em>uals were classifie<em>d</em> as asymptomatic, mil<em>d</em> an<em>d</em> severe pneumonia accor<em>d</em>ing to their clinical, laboratory an<em>d</em> ra<em>d</em>iological characteristics. Worse outcome was <em>d</em>efine<em>d</em> as requirement of intensive care unit (ICU) a<em>d</em>mission or <em>d</em>eath. Bloo<em>d</em> samples were collecte<em>d</em> at enrollment an<em>d</em> serum levels of IL-6 an<em>d</em> IL-18 were <em>d</em>etermine<em>d</em> by ELISA. Association between IL-18 an<em>d</em> other inflammatory markers an<em>d</em> prognosis were analyze<em>d</em>.

<strong class="sub-title"> Results: </strong> There were 58 COVID-19 patients (50% male) with a me<em>d</em>ian age of 43 (min <em>2</em><em>2</em>-max 81) years. Twenty age an<em>d</em> sex matche<em>d</em> healthy subjects were serve<em>d</em> as control group. The stu<em>d</em>y population was <em>d</em>ivi<em>d</em>e<em>d</em> into three groups accor<em>d</em>ing to <em>d</em>isease severity: asymptomatic (n = <em>2</em>0), mil<em>d</em> pneumonia group (n = <em>2</em>7) an<em>d</em> a severe group (n = 11). During follow up nine (15.5%) patients require<em>d</em> ICU a<em>d</em>mission an<em>d</em> three of them were <em>d</em>ie<em>d</em> eventually. Serum IL-18 were correlate<em>d</em> with other inflammatory markers an<em>d</em> biochemical markers of organ injury; creatinine, liver enzymes an<em>d</em> troponin. Serum IL-18 levels were remarkably higher in COVID-19 patients compare<em>d</em> to healthy subjects with being highest in severe pneumonia group (p < 0.001). IL-18 serum concentrations were almost four-fol<em>d</em> higher in patients with worse outcome compare<em>d</em> to goo<em>d</em> outcome (p < 0.001). Serum IL-18 above the cut off value of 576 pg/mL on a<em>d</em>mission was associate<em>d</em> with 11.7 fol<em>d</em> increase<em>d</em> risk of ICU a<em>d</em>mission.

Conclusions: The serum concentrations of IL-18 correlate with other inflammatory markers and reflect disease severity. Results of the present study shed light on role of IL-18 on COVID-19 pathogenesis and might provide an evidence for the clinical trials on IL-18 antagonists for the treatment of severe COVID-19 patients.

Keywords: COVID-19; Cytokine; Intensive care unit; Interleukin-18; Prognosis.

Background: Pregnant women represent a potentially high-risk population in the COVID-19 pandemic.

Objective: To summarize clinical characteristics and outcomes among pregnant women hospitalized with COVID-19.

<strong class="sub-title"> Search strategy: </strong> Relevant databases were searched up until May <em>2</em>9, <em>2</em>0<em>2</em>0.

Selection criteria: Case series/reports of hospitalized pregnant women with laboratory-confirmed COVID-19.

Data collection and analysis: PRISMA guidelines were followed. Methodologic quality was assessed via NIH assessment tools.

<strong class="sub-title"> Main results: </strong> Overall, 63 observational studies of 637 women (84.6% in third trimester) with laboratory-confirmed SARS-CoV-<em>2</em> infection were included. Most (76.5%) women experienced mild disease. Maternal fatality, stillbirth, and neonatal fatality rates were 1.6%, 1.4%, and 1.0%, respectively. Older age, obesity, diabetes mellitus, and raised serum <em>D</em>-<em>dimer</em> and interleukin-6 were predictive of poor outcomes. Overall, 33.7% of live births were preterm, of which half were iatrogenic among women with mild COVI<em>D</em>-19 and no complications. Most women underwent cesarean despite lacking a clear indication. Eight (<em>2</em>.0%) neonates had positive nasopharyngeal swabs after delivery and developed chest infection within 48 hours.

Conclusions: Advanced gestation, maternal age, obesity, diabetes mellitus, and a combination of elevated D-dimer and interleukin-6 levels are predictive of poor pregnancy outcomes in COVID-19. The rate of iatrogenic preterm birth and cesarean delivery is high; vertical transmission may be possible but has not been proved.

Keywords: COVID-19; Intrauterine fetal demise; Maternal morbidity; Maternal mortality; Miscarriage; Neonatal morbidity; Neonatal mortality; Preterm birth.

<strong class="sub-title"> Background: </strong> Observational studies indicate that children hospitalized with COVID-19-related illness, like adults, are at increased risk for venous thromboembolism (VTE). A multicenter phase <em>2</em> clinical trial of anticoagulant thromboprophylaxis in children hospitalized with COVID-19-related illness has recently been initiated in the United States. To date, there remains a paucity of high-quality evidence to inform clinical practice world-wide. Therefore, the objective of this scientific statement is to provide consensus-based recommendations on the use of anticoagulant thromboprophylaxis in children hospitalized for COVID-19-related illnesses, and to identify priorities for future research.

<strong class="sub-title"> Methods: </strong> We surveyed <em>2</em>0 pediatric hematologists and pediatric critical care physicians from several continents who were identified by Pediatric/Neonatal Hemostasis and Thrombosis Subcommittee leadership as having experience and expertise in the use of anticoagulant thromboprophylaxis and/or the management of COVID-19-related illness in children. A comprehensive review of the literature on COVID-19 in children was also performed.

Results: Response rate was 90%. Based on consensus of expert opinions, we suggest the administration of low-dose low molecular weight heparin subcutaneously twice-daily as anticoagulant thromboprophylaxis (in the absence of contraindications, and in combination with mechanical thromboprophylaxis with sequential compression devices, where feasible) in children hospitalized for COVID-19-related illness (including the multisystem inflammatory syndrome in children [MIS-C]) who have markedly elevated D-dimer levels or superimposed clinical risk factors for hospitalassociated VTE. For children who are clinically unstable or have severe renal impairment, we suggest the use of unfractionated heparin by continuous intravenous infusion as anticoagulant thromboprophylaxis. In addition, continued efforts to characterize VTE risk and risk factors in children with COVID-19, as well as to evaluate the safety and efficacy of anticoagulant thromboprophylaxis strategies in children hospitalized with COVID-19-related illness (including MIS-C) via cooperative multicenter trials, were identified among several key priorities for future research.

Conclusion: These consensus-based recommendations on the use of anticoagulant thromboprophylaxis in children hospitalized for COVID-19-related illnesses and priorities for future research will be updated as high-quality evidence emerges.

<strong class="sub-title"> Keywords: </strong> COVID‐19; SARS‐CoV‐<em>2</em>; children; thromboprophylaxis; venous thromboembolism.

<strong class="sub-title"> Background: </strong> Multisystem inflammatory syndrome in children (MIS-C) is a newly identified and serious health condition associated with SARS-CoV-<em>2</em> infection. Clinical manifestations vary widely among patients with MIS-C, and the aim of this study was to investigate factors associated with severe outcomes.

<strong class="sub-title"> Methods: </strong> In this retrospective surveillance study, patients who met the US Centers for Disease Control and Prevention (CDC) case definition for MIS-C (younger than <em>2</em>1 years, fever, laboratory evidence of inflammation, admitted to hospital, multisystem [≥<em>2</em>] organ involvement [cardiac, renal, respiratory, haematological, gastrointestinal, dermatological, or neurological], no alternative plausible diagnosis, and either laboratory confirmation of SARS-CoV-<em>2</em> infection by RT-PCR, serology, or antigen test, or known COVID-19 exposure within 4 weeks before symptom onset) were reported from state and local health departments to the CDC using standard case-report forms. Factors assessed for potential links to severe outcomes included pre-existing patient factors (sex, age, race or ethnicity, obesity, and MIS-C symptom onset date before June 1, <em>2</em>0<em>2</em>0) and clinical findings (signs or symptoms and laboratory markers). Logistic regression models, adjusted for all pre-existing factors, were used to estimate odds ratios between potential explanatory factors and the following outcomes: intensive care unit (ICU) admission, shock, decreased cardiac function, myocarditis, and coronary artery abnormalities.

<strong class="sub-title"> Findings: </strong> 1080 patients met the CDC case definition for MIS-C and had symptom onset between March 11 and Oct 10, <em>2</em>0<em>2</em>0. ICU admission was more likely in patients aged 6-1<em>2</em> years (adjusted odds ratio 1·9 [95% CI 1·4-<em>2</em>·6) and patients aged 13-<em>2</em>0 years (<em>2</em>·6 [1·8-3·8]), compared with patients aged 0-5 years, and more likely in non-Hispanic Black patients, compared with non-Hispanic White patients (1·6 [1·0-<em>2</em>·4]). ICU admission was more likely for patients with shortness of breath (1·9 [1·<em>2</em>-<em>2</em>·9]), abdominal pain (1·7 [1·<em>2</em>-<em>2</em>·7]), and patients with increased concentrations of C-reactive protein, troponin, ferritin, D-dimer, brain natriuretic peptide (BNP), N-terminal pro B-type BNP, or interleukin-6, or reduced platelet or lymphocyte counts. We found similar associations for decreased cardiac function, shock, and myocarditis. Coronary artery abnormalities were more common in male patients (1·5 [1·1-<em>2</em>·1]) than in female patients and patients with mucocutaneous lesions (<em>2</em>·<em>2</em> [1·3-3·5]) or conjunctival injection (<em>2</em>·3 [1·4-3·7]).

Interpretation: Identification of important demographic and clinical characteristics could aid in early recognition and prompt management of severe outcomes for patients with MIS-C.

Funding: None.

<AbstractText>As an acute febrile and inflammatory disease, Kawasaki disease (K<em>D</em>) could develop Kawasaki disease shock syndrome (K<em>D</em>SS) sometimes. However its pathogenesis was still not well known. This study was to learn more about the clinical features and evaluate the role of cytokines in the pathogenesis of K<em>D</em>SS.</AbstractText><AbstractText>We collected clinical and laboratory data retrospectively for all patients with K<em>D</em>SS(K<em>D</em>SS, n = <em>2</em>7)who were hospitalized at our hospital from Jan <em>2</em>014 to Oct <em>2</em>017. For patient with K<em>D</em>SS, we randomly identified 43 patients with K<em>D</em> as control subjects (K<em>D</em>, n = 43). Clinical features, laboratory evaluations were collected. Cytokines IL-<em>2</em>, IL-4, IL-6, IL-10, TNF-α and IFN-γ in serum were assayed using flow cytometric bead array.</AbstractText><AbstractText>The patients with K<em>D</em>SS were older age (43.41 ± 31.4<em>2</em> vs <em>2</em>8.81 ± <em>2</em>1.51 months, P < 0.05), longer duration of fever (10.63 ± 5.1<em>2</em> vs 6.98 ± <em>2</em>.45 days, P < 0.05), higher WBC count, neutrophils, CRP, ESR, PCT and <em>D</em>-<em>dimer</em>, and lower hemoglobin and albumin, more severe hyponatremia and hypokalemia, more refractory to IVIG therapy, more coronary artery abnormalities (CAAs), aseptic meningitis, and longer duration of hospitalization than patients with K<em>D</em> (all P < 0.05). The levels of serum IL-6 [184.1 (<em>2</em>7.7-<em>2</em>577.3) vs 54.1 (4-4<em>2</em>5) pg/ml], IL-10 [4<em>2</em>.6 (5-<em>2</em>36.7) vs 9.4 (3-94) pg/ml], TNF-α [<em>2</em>.6 (1.0-<em>2</em>3.4) vs <em>2</em>.1 (1-6) pg/ml] and IFN-γ [18.3 (4.5-94.4) vs 6.7 (<em>2</em>-56) pg/ml] in K<em>D</em>SS patients were significant higher than K<em>D</em> patients (all P < 0.05). ROC curves showed that 66.7 pg/ml of IL-6, <em>2</em>0.85 pg/ml of IL-10 and 8.35 pg/ml of IFN-γ had sensitivity and specificity for identifying K<em>D</em>SS as 85.<em>2</em> and 6<em>2</em>.8%; 66.7 and 83.7%; 74.1 and 74.4% respectively. No fatality was recorded in this series.</AbstractText><AbstractText>K<em>D</em>SS were characteristic as more cytokine production and prone to developing IVIG non-responsiveness and CAAs. K<em>D</em> patients with IL-6 above 66.7 pg/ml, IL-10 above <em>2</em>0.85 pg/ml, and IFN-γ above 8.35 pg/ml suggested higher risk for K<em>D</em>SS.</AbstractText>

<b>Objective:</b> To understand the clinical characteristics, change of liver function, influencing factors and prognosis in hospitalized patients with coronavirus disease-19 (COVI<em>D</em>-19) combined with liver injury. <b>Methods:</b> The general conditions, biochemical indicators of liver, blood clotting mechanism, routine blood test, UGT1A1 * <em>2</em>8 gene polymorphism and other data of 40 cases with COVI<em>D</em>-19 admitted to the isolation ward of Tangdu Hospital were retrospectively analyzed. The clinical characteristics, influencing factors and prognosis of liver injury in patients with liver injury group and those with normal liver function group were compared. The mean of two samples in univariate analysis was compared by t-test and analysis of variance. The counting data was measured by <i>χ</i>(<em>2</em>) tests. The non-normal distribution measurement data were described by the median, and the non-parametric test was used. Statistically significant influencing factors were used as the independent variables in univariate analysis. Multiple logistic regression analysis was used to analyze the main influencing factors of liver injury. <b>Results:</b> Of the 40 cases, <em>2</em>5 were male (6<em>2</em>.5%) and 15 were female (37.5%), aged <em>2</em><em>2</em> to 83 (53.87 ± 15.84) years. Liver injury was occurred in <em>2</em><em>2</em> cases (55%) during the course of the disease. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level was initially increased (4.4 to 3.5 times of the normal value) along with decrease of albumin in the second week, and the difference was statistically significant (<i>P</i> < 0.001). Ten cases (43.5%) had highest abnormal total blood bilirubin (54.1 μmol/ L). There was no correlation between the increase in transaminase and the increase in total blood bilirubin (<i>R</i> = -0.006, <i>P</i> = 0.97<em>2</em>). Three cases had prothrombin activity (PTA) of ≤ 50%, 10 cases had elevated F<em>D</em>P, and 13 cases had elevated <em>D</em>-<em>dimer</em>, all of whom were severe or critically ill. Liver function injury was more likely to occur in patients who used many types of drugs and large amounts of hormones (<i>P</i> = 0.00<em>2</em>, <i>P</i> = 0.031), and there was no correlation with the TA6TA7 mutation in the UGT1A1 * <em>2</em>8 gene locus. Multiple regression analysis showed that the occurrence of liver injury was only related to critical illness. The liver function of all patients had recovered within one week after conventional liver protection treatment. <b>Conclusion:</b> COVI<em>D</em>-19 combined with liver function injury may be due to the slight elevation of transaminase, mostly around the second week of the disease course. Severe patients have a higher proportion of liver injury, and critical type is an independent risk factor for liver injury.

Randomized clinical trials have identified a population of acute medically ill patients who remain at risk for venous thromboembolism (VTE) beyond the standard duration of therapy and hospital discharge. The aim of the APEX study is to determine whether extended administration of oral betrixaban (35-4<em>2</em> days) is superior to a standard short course of prophylaxis with subcutaneous enoxaparin (10 ± 4 days followed by placebo) in patients with known risk factors for post-discharge VTE. Patients initially are randomized to receive either betrixaban or enoxaparin (and matching placebo) in a double dummy design. Following a standard duration period of enoxaparin treatment (with placebo tablets) or betrixaban (with placebo injections), patients receive only betrixaban (or alternative matching placebo). Patients are considered for enrollment if they are older than 40 years, have a specified medical illness, and restricted mobility. They must also meet the APEX criteria for increased VTE risk (aged ≥75 years, baseline <em>D</em>-<em>Dimer</em> ≥<em>2</em>× upper the limit of "normal", or <em>2</em> additional ancillary risk factors for VTE). The primary efficacy end point is the composite of asymptomatic proximal deep venous thrombosis, symptomatic deep venous thrombosis, non-fatal (pulmonary embolus) pulmonary embolism, or VTE-related death through day 35. The primary safety outcome is the occurrence of major bleeding. We hypothesize that extended duration betrixaban VTE prophylaxis will be safe and more effective than standard short duration enoxaparin in preventing VTE in acute medically ill patients with known risk factors for post hospital discharge VTE.

OBJECTIVE

To assess the extent to which inflammatory, procoagulant, and endothelial biomarkers modify the relationship between diminished renal function and cardiovascular mortality.

RESULTS

Prospective study of 40<em>2</em>9 men aged 60-79 years followed up for a mean period of 6 years, during which 304 cardiovascular deaths occurred. Predicted estimated glomerular filtration rate (eGFR) was used as a measure of renal function. Reduced eGFR was associated with increased prevalence of established cardiovascular risk factors [cardiovascular disease, diabetes, hypertension, left ventricular (LV) hypertrophy, and dyslipidaemia] and higher levels of inflammatory markers [interleukin 6 (IL-6), C-reactive protein], endothelial markers [von Willebrand factor (vWF) and tissue plasminogen activator], activated coagulation markers (fibrin <em>D</em>-<em>dimer</em>), and blood viscosity. Cardiovascular mortality risk increased with decreasing levels of eGFR, particularly among men with eGFR <60 mL/min per 1.73 m(<em>2</em>) even after adjustment for established risk factors (adjusted RR 1.49, 95% CI 1.10, <em>2</em>.03; <60 vs.>> or =70 mL/min per 1.73 m(<em>2</em>)). The association was attenuated after further adjustment for vWF, <em>D</em>-<em>dimer</em>, and IL-6 (adjusted RR 1.34, 95% CI 0.98-1.8<em>2</em>).

CONCLUSIONS

Mild-to-moderate renal insufficiency is associated with significantly increased cardiovascular mortality in elderly men, which is partly explained by the increased prevalence of established risk factors, markers of coagulation, endothelium, and inflammation.

BACKGROUND

Venous thromboembolism (VTE) causes major morbidity in adults after trauma, occurring in up to 50% of patients without prophylaxis. The incidence of VTE after trauma is lower in children. No study has measured the incidence of and risk factors for VTE in critically ill children after trauma.

METHODS

Nested case-control study of children, younger than 18 years, admitted to the pediatric intensive care unit at a level I trauma center. Three controls were selected for each identified VTE case.

RESULTS

Nine of 144 children admitted to the pediatric intensive care unit after trauma developed VTE (incidence 6.<em>2</em>%, 95% confidence interval [CI] <em>2</em>.3-10.<em>2</em>), with a median age of 8.6 years (range, <em>2</em>.3-17.9). VTE was diagnosed at a median of 9 days after admission, with 67% of VTE located at the site of previous or existing central venous line (CVL). Significant risk factors for thrombosis included parenteral nutrition (odds ratio [OR] <em>2</em>0, 95% CI 1.9-<em>2</em><em>2</em>7), CVL (OR 19, 95% CI <em>2</em>-178), deep sedation (OR 13, 95% CI 1.6-48), neuromuscular blockade (OR 10, 95% CI 1.4-70), inotropic support (OR 10, 95% CI 1.7-59), and recombinant factor VIIa administration (p = 0.01<em>2</em>, OR not calculable). Logistic analysis found a 7.9-fold increase in the odds of developing VTE for each additional CVL (p = 0.005), a threefold increase with each additional risk factor present (p = 0.009), and a 1.3-fold increase for an increase in injury severity (p = 0.03). VTE was not associated with sepsis, spinal cord injury, fracture, or elevated <em>D</em>-<em>dimer</em> level.

CONCLUSIONS

VTE is not a rare event in critically ill children after trauma. Most patients developing thrombosis have multiple risk factors, including poor perfusion, immobility, and presence of a CVL.

The mechanism of regulation for the ribozyme activity of hepatitis <em>delta</em> virus (HDV) RNA in infected cells is unknown. Previously, we developed a direct assay capable of detecting the ribozyme activity of HDV <em>dimer</em> or trimer RNAs in vivo (K.-S. Jeng, A. Daniel, and M. M. C. Lai, J. Virol, 70:<em>2</em>403-<em>2</em>410, 1996). In this study, we used this method to examine the effects of hepatitis <em>delta</em> antigen (HDAg) on the ribozyme activities of HDV RNA in vivo. The HDV multimer cDNAs were cotransfected with plasmids encoding either HDV small <em>delta</em> antigen (SHDAg) or large <em>delta</em> antigen (LHDAg), and the self-cleavage of the primary transcripts from the HDV cDNA was analyzed at day <em>2</em> postransfection. The results were as follows. (i) Both HDAgs, particularly LHDAg, enhanced the self-cleavage activity of HDV RNA; however, HDAgs are not required for HDV RNA cleavage. (ii) HDAg could not restore the ribozyme activity of mutant HDV RNAs which have lost the ribozyme function. (iii) The enhancement of ribozyme activity by HDAg does not require HDV RNA replication. (iv) RNA-binding activity of HDAg is required for the enhancement of RNA cleavage. (v) The self-ligation activities of HDV ribozyme also were enhanced by HDAg. These results suggest that HDAg can regulate the cleavage and ligation of HDV RNA during the HDV life cycle.

The activation of fibrinolysis during bicycle ergometry was studied in two pairs of age-matched groups. Group A: 18 healthy male competitive athletes (<em>2</em>3 +/- 3.5 years of age, mean +/- S<em>D</em>), Group B: 18 healthy male volunteers (<em>2</em>5.7 +/- <em>2</em>.7) not engaged in any sports, Group C: 17 healthy male volunteers (50.6 +/- 7.7) regularly practicing sports, and Group <em>D</em>: 18 male survivors from myocardial infarction (MI-patients, 54.<em>2</em> +/- 7.9) who took part in a rehabilitation sports program. Before ergometry, healthy participants with regular sporting activities showed significantly lower plasma plasminogen activator inhibitor capacities (PAI cap) than the members of the respective age-matched control groups: Group A 13.9 +/- <em>2</em>.6 AU/ml, Group B 18.5 +/- 5.5, p less than 0.005; Group C 15.<em>2</em> +/- <em>2</em>.9, Group <em>D</em> <em>2</em>0.7 +/- 5.5, p less than 0.05. <em>D</em>uring ergometry the release of tPA antigen did not differ significantly between the age-matched groups, however, tissue plasminogen activator (tPA) activities after ergometry were higher in groups presenting lower pre-test PAI cap values. Group A 5.5 +/- 6.4 AU/ml, Group B 1.1 +/- <em>2</em>.9 AU/ml, p less than 0.05; Group C <em>2</em>.9 +/- 3.3, Group <em>D</em> 0.<em>2</em> +/- 0.7, p less than 0.05. Levels of the fibrin split product (<em>D</em>-<em>dimer</em>) did not change in any of the groups. This investigation indicates that (1) regular vigorous sporting activities enhance blood fibrinolysis by reducing blood PAI cap in healthy individuals, (<em>2</em>) rehabilitation sport is not capable of reducing blood PAI cap in MI-patients to values measured in age matched healthy individuals regularly practicing sports and (3) the activation of fibrinolysis during physical exercise has no systemic fibrinolytic effect.

The membrane protein M<em>2</em> from influenza-A forms a single-pass transmembrane helix that assembles in lipid membrane as homotetramers whose primary function is to act as a proton transporter for viral acidification. A single residue, histidine 37 (His 37), is known to be responsible for selectivity and plays an integral role in the protein's function. We report pH-dependent (15)N MAS NMR spectra of His 37 within the influenza-A proton conduction domain of M<em>2</em>, M<em>2</em>18-60, which has been previously shown to be a fully functional construct and was recently determined to adopt a <em>dimer</em>-of-<em>dimers</em> structure in lipids. By extracting the ratio of [His]/[HisH(+)] as a function of pH, we obtained two doubly degenerate proton disassociation constants, 7.63 ± 0.15 and 4.5<em>2</em> ± 0.15, despite a possible maximum of four. We also report the (1)HNε chemical shifts at pH 6.5 recorded at 60 kHz MAS in a CP-based (1)H-(15)N spectrum. We were unable to detect resonances indicative of direct proton sharing among His 37 side chains when the tetramer is in the +<em>2</em> state. In the neutral state, His 37 is exclusively in the τ tautomer, indicating that the <em>δ</em> nitrogen is protonated solely as a function of pH. We also found that the plot of [HisH(+)]/[His] as a function of pH is qualitatively similar to previously reported proton conduction rates, indicating that proton conduction rate is proportional to the level of histidine protonation within the channel. Two-dimensional (13)C-(13)C and (13)C-(15)N correlations suggest that at low pH multiple conformations are populated as the spectra broaden and eventually disappear as the acidity is increased. A second highly resolved state at low pH was not observed.

myo-Inositol-1-phosphatase has been purifie<em>d</em> to homogeneity from Lilium longiflorum pollen using an alternative proce<em>d</em>ure which inclu<em>d</em>es pH change an<em>d</em> phenyl Sepharose column chromatography. So<em>d</em>ium <em>d</em>o<em>d</em>ecyl sulfate-polyacrylami<em>d</em>e gel electrophoretic analysis shows that the enzyme is a <em>dimer</em> (subunit molecular weight, <em>2</em>9,000 <em>d</em>altons). The enzyme is stable at low pH values an<em>d</em> is inactivate<em>d</em> only below pH 3.0. In a<em>d</em><em>d</em>ition to 1l-an<em>d</em> 1<em>d</em>-myo-inositol-1-phosphate, it shows high specificity for 1l-chiro-inositol-3-phosphate. As observe<em>d</em> earlier with other primary phosphate esters, <em>d</em>-glucitol-6-phosphate an<em>d</em> <em>d</em>-mannitol-6-phosphate are hy<em>d</em>rolyze<em>d</em> very slowly. No activity is observe<em>d</em> with inorganic pyrophosphate or myo-inositol pentaphosphate as substrate. The enzyme is inhibite<em>d</em> by fluori<em>d</em>e, sulfate, molyb<em>d</em>ate, an<em>d</em> thiol-<em>d</em>irecte<em>d</em> reagents. Partial protection against N-ethylmaleimi<em>d</em>e inhibition by substrate an<em>d</em> Mg(<em>2</em>+) together suggests sulfhy<em>d</em>ryl involvement at the active site.

BACKGROUND

The role of risk stratification in normotensive patients with acute pulmonary embolism (PE) is still unclear.

OBJECTIVE

We evaluated, in these patients, the usefulness of six prognostic markers for predicting in-hospital adverse events related to PE and 3-month mortality.

METHODS

Two hundred and one consecutive patients with confirmed acute PE and normal blood pressure, who were administered conventional anticoagulation, were recruited in a multicentre prospective cohort study with 3 months of follow-up. At baseline, they received a comprehensive risk-evaluation including echocardiographic assessment of right ventricular dysfunction, determination of troponin I, brain natriuretic peptide and D-dimer, arterial blood gas analysis and a clinical score. Primary outcome of the study was PE-related in-hospital death or clinical deterioration. Secondary outcomes were in-hospital and 3-month all-cause mortality.

RESULTS

The primary outcome occurred in one patient (0.5%), who died from PE during hospitalization. The in-hospital and 3-month all-cause mortality were 2% and 9%, respectively. None of the prognostic markers was predictive of the primary outcome. Clinical score, troponin I and hypoxemia predicted in-hospital all-cause mortality (P = 0.02, 0.01 and < 0.01, respectively). Clinical score (HR, 4.7; 95% CI, 1.9-12.0), D-dimer (4.8; 1.4-16.3), hypoxemia (5.7; 2.1-15.1) and troponin I (7.5; 2.5-22.7) were predictors of 3-month all-cause mortality on univariate analysis. On multivariate analysis clinical score and troponin I remained independently predictive.

CONCLUSIONS

We did not find prognostic markers useful as predictors of in-hospital PE-related adverse events. Clinical score, troponin I and hypoxemia predicted in-hospital all-cause mortality. Clinical score and troponin I independently predicted 3-month all-cause mortality.

Aspartate aminotransferase from the archaebacterium Sulfolobus solfataricus, a thermoacidophilic organism isolated from an acidic hot spring (optimal growth conditions: 87 degrees C, pH 3.5) was purified to homogeneity. The enzyme is a <em>dimer</em> (Mr subunit = 53,000) showing microheterogeneity when submitted to chromatofocusing and/or isoelectric focusing analysis (two main bands having pI = 6.8 and 6.3 were observed). The N-terminal sequence (<em>2</em><em>2</em> residues) does not show any homology with any stretch of known sequence of aspartate aminotransferases from animal and bacterial sources. The apoenzyme can be reconstituted with pyridoxamine 5'-phosphate and/or pyridoxal 5'-phosphate, each subunit binding 1 mol of coenzyme. The absorption maxima of the pyridoxamine and pyridoxal form are centered at 3<em>2</em>5 and 335 nm, respectively; the shape of the pyridoxal form band does not change with pH. The enzyme has an optimum temperature higher than 95 degrees C, and at 100 degrees C shows a half-inactivation time of <em>2</em> h. The above properties seem to be unique even for enzymes from extreme thermophiles (<em>D</em>aniel, R. M. (1986) in Protein Structure, Folding, and <em>D</em>esign (Oxender, <em>D</em>. L., ed) pp. <em>2</em>91-<em>2</em>96, Alan R. Liss, Inc., New York) and lead to the conclusion that aspartate aminotransferase from S. solfataricus is one of the most thermophilic and thermostable enzymes so far known.

Trichothiodystrophy is a genetic disease which in the majority of cases studied is associated with a deficiency in the ability to repair UV damage in cellular <em>D</em>NA. Three categories of UV response have been identified. In type 1 the response is completely normal, whereas type <em>2</em> cells are deficient in excision-repair, with properties indistinguishable from those of XP complementation group <em>D</em>. Type 3 cells have normal survival following UV-irradiation and normal rates of removal of cyclobutane pyrimidine <em>dimer</em> sites. Nevertheless repair synthesis is reduced by 50% in these cell strains and this is associated with a marked reduction in the repair of 6-4 photoproducts from cellular <em>D</em>NA. The present results show that 50% or more of repair synthesis at early times after irradiation of normal primary human fibroblasts is attributable to repair of 6-4 products. They also suggest that repair of cyclobutane <em>dimers</em> is crucial for cell survival.

<em>D</em>opamine <em>D</em>(<em>2</em>) receptor homo<em>dimer</em>s might be of particular importance in the pathophysiology of schizophrenia and, thus, serve as promising target proteins for the discovery of atypical antipsychotics. A highly attractive approach to investigate and control GPCR <em>dimer</em>ization may be provided by the exploration and characterization of bivalent ligands, which can act as molecular probes simultaneously binding two adjacent binding sites of a <em>dimer</em>. The synthesis of bivalent dopamine <em>D</em>(<em>2</em>) receptor ligands of type 1 is presented, incorporating the privileged structure of 1,4-disubstituted aromatic piperidines/piperazines (1,4-<em>D</em>APs) and triazolyl-linked spacer elements. Radioligand binding studies provided diagnostic insights when Hill slopes close to two for bivalent ligands with particular spacer lengths and a comparative analysis with respective monovalent control ligands and unsymmetrically substituted analogues indicated a bivalent binding mode with a simultaneous occupancy of two neighboring binding sites.

<em>D</em>uring replication, the lengthy genome of double-stranded <em>D</em>NA viruses is translocated with remarkable velocity into a limited space within the procapsid. The question of how this fascinating task is accomplished has long been a puzzle. Our recent investigation suggests that phi<em>2</em>9 <em>D</em>NA packaging is accomplished by a mechanism similar to the driving of a bolt with a hex nut and that six packaging RNAs (pRNAs) form a hexagonal complex to gear the <em>D</em>NA-translocating machine (Chen, C., and Guo, P. (1997) J. Virol. 71, 3864-3871; Zhang, F., Lemieux, S., Wu, X., St.-Arnaud, S., McMurray, C. T., Major, F., and Anderson, <em>D</em>. (1998) Mol. Cell <em>2</em>, 141-147; Guo, P., Zhang, C., Chen, C., Garver, K., and Trottier, M., (1998) Mol. Cell <em>2</em>, 149-155). In the current study, circularly permuted pRNAs were used to position an azidophenacyl photoreactive cross-linking agent specifically at a strategic site that was predicted to be involved in pRNA-pRNA interaction. Cross-linked pRNA <em>dimers</em> were isolated, and the sites of cross-link were mapped by primer extension. The cross-linked pRNA <em>dimer</em> retained full activity in phi<em>2</em>9 procapsid binding and genomic <em>D</em>NA translocation, indicating that the cross-link distance constraints identified in <em>dimer</em> formation reflect the native pRNA complex. Both cross-linked <em>dimers</em> either containing or not containing the interlocking loops for programmed hexamer formation bound procapsid equally well; however, only the one containing the interlocking loops programmed for hexamer formation was active in phi<em>2</em>9 <em>D</em>NA packaging. The cross-linked pRNA <em>dimers</em> were also identified as the minimum binding unit necessary for procapsid binding. Primer extension of the purified cross-linked pRNA <em>dimers</em> revealed that base G(8<em>2</em>) was cross-linked to bases G(39), G(40), A(41), C(49), G(6<em>2</em>), C(63), and C(64), which contribute to the formation of the three-way junction, suggesting that these bases are proximate in the formation of pRNA tertiary structure. Interestingly, the photoaffinity agent in the left interacting loop did not cross-link directly to the right loop as expected but cross-linked to bases adjacent to the right loop. These data provide a background for future modeling of pRNA tertiary structure.