Publications about D 2 Dimer

Publication

A clinical prediction model for cancer-associated venous thromboembolism: a development and validation study in two independent prospective cohorts.

Journal: The Lancet Haematology

October/17/2018

Abstract

BACKGROUND

Venous thromboembolism is a common complication of cancer, but the risk of developing venous thromboembolism varies greatly among individuals and depends on numerous factors, including type of cancer. We aimed to develop and externally validate a clinical prediction model for cancer-associated venous thromboembolism.

METHODS

We used data from the prospective Vienna Cancer and Thrombosis Study (CATS) cohort (n=1423) to select prognostic variables for inclusion in the model. We then validated the model in the prospective Multinational Cohort Study to Identify Cancer Patients at High Risk of Venous Thromboembolism (MICA) cohort (n=832). We calculated c-indices to show how the predicted incidence of objectively confirmed venous thromboembolism at 6 months compared with the cumulative 6-month incidences observed in both cohorts.

RESULTS

Two variables were selected for inclusion in the final clinical prediction model: tumour-site risk category (low or intermediate vs high vs very high) and continuous D-dimer concentrations. The multivariable subdistribution hazard ratios were 1·96 (95% CI 1·41-2·72; p=0·0001) for high or very high versus low or intermediate and 1·32 (95% CI 1·12-1·56; p=0·001) per doubling of D-dimer concentration. The cross-validated c-indices of the final model were 0·66 (95% CI 0·63-0·67) in CATS and 0·68 (0·62-0·74) in MICA. The clinical prediction model was adequately calibrated in both cohorts.

CONCLUSIONS

An externally validated clinical prediction model incorporating only one clinical factor (tumour-site category) and one biomarker (D-dimer) predicted the risk of venous thromboembolism in ambulatory patients with solid cancers. This simple model is a considerable improvement on previous models for predicting cancer-associated venous thromboembolism, and could aid physicians in selection of patients who will likely benefit from thromboprophylaxis.

BACKGROUND

Austrian Science Fund, Austrian National Bank Memorial Fund, and participating hospitals.

Authors

Ingrid Pabinger; Nick van Es; Georg Heinze; Florian Posch; Julia Riedl; Eva-Maria Reitter+6 authors

Publication

Genome-wide association and linkage analyses of hemostatic factors and hematological phenotypes in the Framingham Heart Study.

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Journal: BMC Medical Genetics

November/6/2007

Abstract

BACKGROUND

Increased circulating levels of hemostatic factors as well as anemia have been associated with increased risk of cardiovascular disease (CVD). Known associations between hemostatic factors and sequence variants at genes encoding these factors explain only a small proportion of total phenotypic variation. We sought to confirm known putative loci and identify novel loci that may influence either trait in genome-wide association and linkage analyses using the Affymetrix GeneChip 100K single nucleotide polymorphism (SNP) set.

METHODS

Plasma levels of circulating hemostatic factors (fibrinogen, factor VII, plasminogen activator inhibitor-1, von Willebrand factor, tissue plasminogen activator, D-dimer) and hematological phenotypes (platelet aggregation, viscosity, hemoglobin, red blood cell count, mean corpuscular volume, mean corpuscular hemoglobin concentration) were obtained in approximately 1000 Framingham Heart Study (FHS) participants from 310 families. Population-based association analyses using the generalized estimating equations (GEE), family-based association test (FBAT), and multipoint variance components linkage analyses were performed on the multivariable adjusted residuals of hemostatic and hematological phenotypes.

RESULTS

In association analysis, the lowest GEE p-value for hemostatic factors was p = 4.5*10(-16) for factor VII at SNP rs561241, a variant located near the F7 gene and in complete linkage disequilibrium (LD) (r2 = 1) with the Arg353Gln F7 SNP previously shown to account for 9% of total phenotypic variance. The lowest GEE p-value for hematological phenotypes was 7*10(-8) at SNP rs2412522 on chromosome 4 for mean corpuscular hemoglobin concentration. We presented top 25 most significant GEE results with p-values in the range of 10(-6) to 10(-5) for hemostatic or hematological phenotypes. In relating 100K SNPs to known candidate genes, we identified two SNPs (rs1582055, rs4897475) in erythrocyte membrane protein band 4.1-like 2 (EPB41L2) associated with hematological phenotypes (GEE p < 10(-3)). In linkage analyses, the highest linkage LOD score for hemostatic factors was 3.3 for factor VII on chromosome 10 around 15 Mb, and for hematological phenotypes, LOD 3.4 for hemoglobin on chromosome 4 around 55 Mb. All GEE and FBAT association and variance components linkage results can be found at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007 webcite.

CONCLUSIONS

Using genome-wide association methodology, we have successfully identified a SNP in complete LD with a sequence variant previously shown to be strongly associated with factor VII, providing proof of principle for this approach. Further study of additional strongly associated SNPs and linked regions may identify novel variants that influence the inter-individual variability in hemostatic factors and hematological phenotypes.

Authors

Qiong Yang; Sekar Kathiresan; Jing-Ping Lin; Geoffrey H Tofler; Christopher J O'Donnell

Publication

DNA-induced dimerization of the Escherichia coli rep helicase. Allosteric effects of single-stranded and duplex DNA.

Journal: Journal of Biological Chemistry

May/11/1992

Abstract

The Escherichia coli Rep helicase is a stable monomer (Mr = 72,802) in the absence of DNA; however, binding of single-stranded (ss) or duplex (ds) DNA induces Rep monomers to dimerize. Furthermore, a chemically cross-linked Rep dimer retains both its DNA-dependent ATPase and helicase activities, suggesting that the functionally active Rep helicase is a dimer (Chao, K., and Lohman, T. M. (1991) J. Mol. Biol. 221, 1165-1181). Using a modified "double-filter" nitrocellulose filter binding assay, we have examined quantitatively the equilibrium binding of Rep to a series of ss-oligodeoxynucleotides, d(pN)n (8 less than or equal to n less than or equal to 20) and two 16-base pair duplex oligodeoxynucleotides, which are short enough so that only a single Rep monomer can bind to each oligonucleotide. This strategy has enabled us to examine the linkage between DNA binding and dimerization. We also present a statistical thermodynamic model to describe the DNA-induced Rep dimerization in the presence of ss- and/or ds-oligodeoxynucleotides. We observe quantitative agreement between this model and the experimental binding isotherms and have analyzed these isotherms to obtain the seven independent interaction constants that describe Rep-DNA binding and Rep dimerization. We find that Rep monomers (P) can bind either ss-DNA (S) or ds-DNA (D) to form PS or PD, respectively, which can then dimerize to form P2S or P2D. Furthermore, both protomers of the DNA-induced Rep dimer can bind DNA to form either P2S2, P2D2 or the mixed dimer species P2SD and ss- and ds-DNA compete for the same sites on the Rep protein. When bound to DNA, the Rep dimerization constants are approximately 1-2 x 10(8) M-1 (6 mM NaCl, pH 7.5, 4 degrees C), which are greater than the dimerization constant for free Rep monomers by at least 10(4)-fold. The Rep-ss-DNA interaction constants are independent of base composition and sequence, consistent with its role as a nonspecific DNA-binding protein. Allosteric effects are associated with ss- and ds-DNA binding to the half-saturated Rep dimers, i.e. the affinity of either ss- or ds-DNA to the free promoter of a half-saturated Rep dimer is clearly influenced by the conformation of DNA bound to the first protomer. These allosteric effects further support the proposal that the Rep dimer is functionally important and that the Rep-DNA species P2S2 and P2SD may serve as useful models for intermediates that occur during DNA unwinding.(ABSTRACT TRUNCATED AT 400 WORDS)

Authors

I Wong; K L Chao; W Bujalowski; T M Lohman

Publication

Solution structure of the mithramycin dimer-DNA complex.

Journal: Biochemistry

August/12/1993

Abstract

We have characterized the NMR parameters for the complexes formed by the Mg(2+)-coordinated mithramycin dimer with self-complementary d(T-G-G-C-C-A) and d(T-C-G-C-G-A) duplexes. The solution structure of the latter complex has been determined using a combined NMR-molecular dynamics study including relaxation matrix refinement. The Mg(2+)-coordinated mithramycin dimer-d(T-C-G-C-G-A) complex exhibits a 2-fold center of symmetry with the divalent cation coordinated aglycons positioned opposite the central (G3-C4).(G3-C4) segment such that the aglycon C8 hydroxyl oxygens form symmetrical sequence-specific hydrogen bonds to guanine amino protons in the complex. The C-D-E trisaccharide segments of each monomer in the mithramycin dimer adopt extended conformations, are positioned inside the minor groove, and are directed toward either end of the duplex. The C-D saccharide component of one monomer and the aglycon of the other monomer in the mithramycin dimer share a widened minor groove with the hydrophobic edges of the C and D sugars interacting with individual strands of the duplex. The E-sugar ring is positioned in the floor of the minor groove, and its hydroxyl-bearing face interacts with both strands of the duplex through hydrogen-bonding and hydrophobic intermolecular interactions. The A-B disaccharide and the hydrophilic side chain form intermolecular contacts with the sugar-phosphate backbone in the complex. The antiparallel alignment of divalent cation coordinated monomers in the mithramycin dimer results in the two outwardly directed C-D-E trisaccharide segments generating a right-handed continuous hexasaccharide domain that spans six base pairs in the minor groove of the duplex. The solution structure of the mithramycin dimer-DNA complex reported in this study and the solution structure of the chromomycin dimer-DNA complex reported previously [Gao, X., Mirau, P., & Patel, D. J. (1992) J. Mol. Biol. 223, 259-279] show global similarities, as well as local differences that are of interest. All four nucleotides in the tetranucleotide segment of the duplex centered about the sequence-specific (G-C).(G-C) step adopt A-DNA sugar puckers and glycosidic torsion angles in the chromomycin dimer-DNA complex, while only the central cytidine adopts an A-DNA sugar pucker and glycosidic torsion angle in the mithramycin dimer-DNA complex.(ABSTRACT TRUNCATED AT 400 WORDS)

Authors

M Sastry; D J Patel

Publication

Cryo-negative staining.

Journal: Micron

August/11/1998

Abstract

A procedure is presented for the preparation of thin layers of vitrified biological suspensions in the presence of ammonium molybdate, which we term cryo-negative staining. The direct blotting of sample plus stain solution on holey carbon supports produces thin aqueous films across the holes, which are routinely thinner than the aqueous film produced by conventional negative staining on a continuous carbon layer. Because of this, a higher than usual concentration of negative stain (ca. 16% rather than 2%) is required for cryo-negative staining in order to produce an optimal image contrast. The maintenance of the hydrated state, the absence of adsorption to a carbon film and associated sample flattening, together with reduced stain granularity, generates high contrast cryo-images of superior quality to conventional air-dry negative staining. Image features characteristic of unstained vitrified cryo-electron microscopic specimens are present, but with reverse contrast. Examples of cryo-negative staining of several particulate biological samples are shown, including bacteriophage T2, tobacco mosaic virus (TMV), bovine liver catalase crystals, tomato bushy stunt virus (TBSV), turnip yellow mosaic virus (TYMV), keyhole limpet hemocyanin (KLH) types 1 and 2, the 20S proteasome from moss and the E. coli chaperone GroEL. Densitometric quantitation of the mass-density of cryo-negatively stained bacteriophage T2 specimens before and after freeze-drying within the TEM indicates a water content of 30% in the vitreous specimen. Determination of the image resolution from cryo-negatively stained TMV rods and catalase crystals shows the presence of optical diffraction data to ca. 10 A and 11.5 A, respectively. For cryo-negatively stained vitrified catalase crystals, electron diffraction shows that atomic resolution is preserved (to better than 20 diffraction orders and less than 3 A). The electron diffraction resolution is reduced to ca. 10 A when catalase crystal specimens are prepared without freezing or when they are freeze-dried in the electron microscope. Thin vitrified films of TMV, TBSV and TYMV in the presence of 16% ammonium molybdate show a clear indication of two-dimensional (2-D) order, confirmed by single particle orientational analysis of TBSV and 2-D crystallographic analysis of TYMV. These observations are in accord with earlier claims that ammonium molybdate induces 2-D array and crystal formation from viruses and macromolecules during drying onto mica. Three-dimensional analysis of the TBSV sample using the tools of icosahedral reconstruction revealed that a significant fraction of the particles were distorted. A reconstruction from a subset of undistorted particles produced the characteristic T = 3 dimer clustered structure of TBSV, although the spikes are shortened relative to the structure defined by X-ray crystallography. The 20S proteasome, GroEL, catalase, bacteriophage T2, TMV, TBSV and TYMV all show no indication of sample instability during cryo-negative staining. However, detectable dissociation of the KLH2 oligomers in the presence of the high concentration of ammonium molybdate conforms with existing knowledge on the molybdate-induced dissociation of this molecule. This indicates that the possibility of sample-stain interaction in solution, prior to vitrification, must always be carefully assessed.

Authors

M Adrian; J Dubochet; S D Fuller; J R Harris

Publication

Thermodynamics of CFTR channel gating: a spreading conformational change initiates an irreversible gating cycle.

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Journal: Journal of General Physiology

December/27/2006

Abstract

CFTR is the only ABC (ATP-binding cassette) ATPase known to be an ion channel. Studies of CFTR channel function, feasible with single-molecule resolution, therefore provide a unique glimpse of ABC transporter mechanism. CFTR channel opening and closing (after regulatory-domain phosphorylation) follows an irreversible cycle, driven by ATP binding/hydrolysis at the nucleotide-binding domains (NBD1, NBD2). Recent work suggests that formation of an NBD1/NBD2 dimer drives channel opening, and disruption of the dimer after ATP hydrolysis drives closure, but how NBD events are translated into gate movements is unclear. To elucidate conformational properties of channels on their way to opening or closing, we performed non-equilibrium thermodynamic analysis. Human CFTR channel currents were recorded at temperatures from 15 to 35 degrees C in inside-out patches excised from Xenopus oocytes. Activation enthalpies(DeltaH(double dagger)) were determined from Eyring plots. DeltaH(double dagger) was 117 +/- 6 and 69 +/- 4 kJ/mol, respectively, for opening and closure of partially phosphorylated, and 96 +/- 6 and 73 +/- 5 kJ/mol for opening and closure of highly phosphorylated wild-type (WT) channels. DeltaH(double dagger) for reversal of the channel opening step, estimated from closure of ATP hydrolysis-deficient NBD2 mutant K1250R and K1250A channels, and from unlocking of WT channels locked open with ATP+AMPPNP, was 43 +/- 2, 39 +/- 4, and 37 +/- 6 kJ/mol, respectively. Calculated upper estimates of activation free energies yielded minimum estimates of activation entropies (DeltaS(double dagger)), allowing reconstruction of the thermodynamic profile of gating, which was qualitatively similar for partially and highly phosphorylated CFTR. DeltaS(double dagger) appears large for opening but small for normal closure. The large DeltaH(double dagger) and DeltaS(double dagger) (TDeltaS(double dagger)>>/= 41 kJ/mol) for opening suggest that the transition state is a strained channel molecule in which the NBDs have already dimerized, while the pore is still closed. The small DeltaS(double dagger) for normal closure is appropriate for cleavage of a single bond (ATP's beta-gamma phosphate bond), and suggests that this transition state does not require large-scale protein motion and hence precedes rehydration (disruption) of the dimer interface.

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Authors

László Csanády; Angus C Nairn; David C Gadsby

Publication

Predictive value of D-dimer test for recurrent venous thromboembolism after anticoagulation withdrawal in subjects with a previous idiopathic event and in carriers of congenital thrombophilia.

Journal: Circulation

August/12/2003

Abstract

BACKGROUND

We have shown that normal D-dimer levels obtained after the discontinuation of oral anticoagulant treatment (OAT) has a high negative predictive value for recurrent venous thromboembolism (VTE). The aim of the present study was to assess the predictive value of D-dimer for recurrent VTE in subjects with a previous unprovoked event who are either carriers of inherited thrombophilia or not.

RESULTS

We prospectively evaluated 599 patients (301 males) with a previous VTE episode. They were repeatedly examined for D-dimer levels after OAT withdrawal and were screened for inherited thrombophilic alterations. Alterations were detected in 130 patients (21.7%), factor V Leiden (70 patients; 2 of whom were homozygotes) and prothrombin mutation (38 patients) were the most prevalent ones. Recurrent events were recorded in 58 subjects (9.7%) during a follow-up of 870.7 patient-years. Altered D-dimer levels at 1 month after OAT withdrawal were associated with a higher rate of subsequent recurrence in all subjects investigated, especially in those with an unprovoked qualifying VTE event (hazard ratio, 2.43; 95% confidence interval, 1.18 to 4.61) and in those with thrombophilia (hazard ratio, 8.34; 95% confidence interval, 2.72 to 17.43). The higher relative risk for recurrence of altered D-dimer was confirmed by multivariate analysis after adjustment for other risk factors. The negative predictive value of D-dimer was 92.9% and 95.8% in subjects with an unprovoked qualifying event or with thrombophilia, respectively.

CONCLUSIONS

D-dimer levels measured 1 month after OAT withdrawal have a high negative predictive value for recurrence in subjects with unprovoked VTE who are either carriers or not carriers of congenital thrombophilia.

Authors

Gualtiero Palareti; Cristina Legnani; Benilde Cosmi; Lelia Valdré; Barbara Lunghi; Francesco Bernardi; Sergio Coccheri

Publication

Reduced clot permeability and susceptibility to lysis in patients with acute coronary syndrome: effects of inflammation and oxidative stress.

Journal: Atherosclerosis

March/23/2008

Abstract

BACKGROUND

Stable angina is associated with unfavorable fibrin structure/function. It is not known how acute coronary syndromes (ACS) affect fibrin architecture.

OBJECTIVE

We investigated fibrin clot properties and their determinants in ACS patients.

METHODS

Clot permeability, turbidity and fibrinolysis were assessed in 40 patients with ACS versus 40 controls with stable angina matched for age, sex, and risk factors.

RESULTS

Patients with ACS had lower clot permeability (p=0.001), faster fibrin polymerization (p=0.008), and prolonged fibrinolysis time (p<0.0001) than controls. C-reactive protein (CRP) and 8-epi-prostaglandin F(2alpha), a marker of oxidative stress, were the only independent predictors of clot permeability (R(2)=-0.74; p<0.0001 and R(2)=-0.65; p<0.0001, respectively) and fibrinolysis time in ACS patients (R(2)=0.60; p<0.0001 and R(2)=0.59; p=0.0002, respectively). In angina patients, fibrinogen and CRP predicted permeability (R(2)=-0.71; p<0.0001 and R(2)=-0.62; p<0.0001), and D-dimer predicted lysis time (R(2)=0.54; p=0.0005). In regression analysis models incorporating all patients, the only independent predictor of all clot variables was being an ACS patient (R(2) 0.51 to 0.85; p<0.001).

CONCLUSIONS

This first study of clot properties in patients during an ACS demonstrated that compared with stable angina patients, their clots are composed of dense networks that are more resistant to lysis and these features are correlated with raised CRP and oxidative stress.

Authors

Anetta Undas; Konstanty Szułdrzynski; Ewa Stepien; Jarosław Zalewski; Jacek Godlewski; Wiesława Tracz+2 authors

Publication

D-dimer, P-selectin, and microparticles: novel markers to predict deep venous thrombosis. A pilot study.

Journal: Thrombosis and Haemostasis

April/26/2006

Abstract

Current plasma markers for diagnosis of deep venous thrombosis (DVT) allow for exclusion of the diagnosis, but lack adequate specificity to establish the diagnosis. Thus, a prospective study was performed to determine the sensitivity and specificity of plasma assays for D-dimer, soluble P-selectin (P-selectin), and total microparticles in patients with documented DVT by duplex ultrasound. Three groups of individuals were examined: 30 normals; 22 positive for DVT on duplex ultrasound (Group 2); and 21 symptomatic, but negative on duplex ultrasound for DVT (Group 3). Group 1 individuals had D-dimer values of 1.53 +/- 0.12 mg/l and P-selectin values of 0.34 +/- 0.05 ng/mg total protein. Group 2 vs. Group 3 individuals had D-dimer values of 7.57 +/- 2.03 vs. 3.19 +/- 0.79 mg/l, p = 0.02; P-selectin values of 0.98 +/- 0.11 vs. 0.55 +/- 0.08 ng/mg total protein, p < 0.01; and micro-particle values of 129 +/- 17% vs. 99 +/- 12% of control, p = ns. Using a logistic regression model with dichotomous variables, we determined a sensitivity of 73%, specificity of 81%, and accuracy of 77% when combining D-dimer, soluble P-selectin, and total microparticles to differentiate Group 2 from Group 3 patients. Logistic regression using continuous variables yielded similar results (p = 0.05). This study demonstrates that plasma markers for DVT can be developed and achieve moderate sensitivity and specificity in diagnosing DVT. However for clinical applicability, the sensitivity/specificity will need to be improved. These studies also suggest the importance of soluble P-selectin in assessing DVT in humans.

Authors

John E Rectenwald; Daniel D Myers; Angela E Hawley; Christopher Longo; Peter K Henke; Kenneth E Guire+2 authors

Publication

Prognostic factors associated with mortality risk and disease progression in 639 critically ill patients with COVID-19 in Europe: Initial report of the international RISC-19-ICU prospective observational cohort

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Journal: EClinicalMedicine

August/24/2020

Abstract

Background: Coronavirus disease 2019 (COVID-19) is associated with a high disease burden with 10% of confirmed cases progressing towards critical illness. Nevertheless, the disease course and predictors of mortality in critically ill patients are poorly understood.

Methods: Following the critical developments in ICUs in regions experiencing early inception of the pandemic, the European-based, international RIsk Stratification in COVID-19 patients in the Intensive Care Unit (RISC-19-ICU) registry was created to provide near real-time assessment of patients developing critical illness due to COVID-19.

Findings: As of April 22, 2020, 639 critically ill patients with confirmed SARS-CoV-2 infection were included in the RISC-19-ICU registry. Of these, 398 had deceased or been discharged from the ICU. ICU-mortality was 24%, median length of stay 12 (IQR, 5-21) days. ARDS was diagnosed in 74%, with a minimum P/F-ratio of 110 (IQR, 80-148). Prone positioning, ECCO2R, or ECMO were applied in 57%. Off-label therapies were prescribed in 265 (67%) patients, and 89% of all bloodstream infections were observed in this subgroup (n = 66; RR=3·2, 95% CI [1·7-6·0]). While PCT and IL-6 levels remained similar in ICU survivors and non-survivors throughout the ICU stay (p = 0·35, 0·34), CRP, creatinine, troponin, d-dimer, lactate, neutrophil count, P/F-ratio diverged within the first seven days (p<0·01). On a multivariable Cox proportional-hazard regression model at admission, creatinine, d-dimer, lactate, potassium, P/F-ratio, alveolar-arterial gradient, and ischemic heart disease were independently associated with ICU-mortality.

Interpretation: The European RISC-19-ICU cohort demonstrates a moderate mortality of 24% in critically ill patients with COVID-19. Despite high ARDS severity, mechanical ventilation incidence was low and associated with more rescue therapies. In contrast to risk factors in hospitalized patients reported in other studies, the main mortality predictors in these critically ill patients were markers of oxygenation deficit, renal and microvascular dysfunction, and coagulatory activation. Elevated risk of bloodstream infections underscores the need to exercise caution with off-label therapies.

Keywords: Acute respiratory distress syndrome; COVID-19; Coronavirus; Pandemic; Public health.

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Temporal progression of organ function, vital, and laboratory parameters over the initial seven...

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Risk factors associated with ICU mortality. Prognostication of ICU mortality in a multivariable...

Authors

Pedro Garcia; Thierry Fumeaux; Philippe Guerci; Dorothea Heuberger; Jonathan Montomoli; Ferran Roche-Campo+3 authors

Publication

Disseminated intravascular coagulation or acute coagulopathy of trauma shock early after trauma? An observational study.

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Journal: Critical Care

June/11/2013

Abstract

BACKGROUND

It is debated whether early trauma-induced coagulopathy (TIC) in severely injured patients reflects disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype, acute coagulopathy of trauma shock (ACoTS) or yet other entities. This study investigated the prevalence of overt DIC and ACoTS in trauma patients and characterized these conditions based on their biomarker profiles.

METHODS

An observational study was carried out at a single Level I Trauma Center. Eighty adult trauma patients (≥18 years) who met criteria for full trauma team activation and had an arterial cannula inserted were included. Blood was sampled a median of 68 minutes (IQR 48 to 88) post-injury. Data on demography, biochemistry, injury severity score (ISS) and mortality were recorded. Plasma/serum was analyzed for biomarkers reflecting tissue/endothelial cell/glycocalyx damage (histone-complexed DNA fragments, Annexin V, thrombomodulin, syndecan-1), coagulation activation/inhibition (prothrombinfragment 1+2, thrombin/antithrombin-complexes, antithrombin, protein C, activated protein C, endothelial protein C receptor, protein S, tissue factor pathway inhibitor, vWF), factor consumption (fibrinogen, FXIII), fibrinolysis (D-dimer, tissue-type plasminogen activator, plasminogen activator inhibitor-1) and inflammation (interleukin (IL)-6, terminal complement complex (sC5b-9)). Comparison of patients stratified according to the presence or absence of overt DIC (International Society of Thrombosis and Hemostasis (ISTH) criteria) or ACoTS (activated partial thromboplastin time (APTT) and/or international normalized ratio (INR) above normal reference).

RESULTS

No patients had overt DIC whereas 15% had ACoTS. ACoTS patients had higher ISS, transfusion requirements and mortality (all P < 0.01) and a biomarker profile suggestive of enhanced tissue, endothelial cell and glycocalyx damage and consumption coagulopathy with low protein C, antithrombin, fibrinogen and FXIII levels, hyperfibrinolysis and inflammation (all P < 0.05). Importantly, in non-ACoTS patients, apart from APTT/INR, higher ISS correlated with biomarkers of enhanced tissue, endothelial cell and glycocalyx damage, protein C activation, coagulation factor consumption, hyperfibrinolysis and inflammation, that is, resembling that observed in patients with ACoTS.

CONCLUSIONS

ACoTS and non-ACoTS may represent a continuum of coagulopathy reflecting a progressive early evolutionarily adapted hemostatic response to the trauma hit and both are parts of TIC whereas DIC does not appear to be part of this early response.

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Authors

Pär I Johansson; Anne Marie Sørensen; Anders Perner; Karen Lise Welling; Michael Wanscher; Claus F Larsen; Sisse R Ostrowski

Publication

Coagulation activation and microparticle-associated coagulant activity in cancer patients. An exploratory prospective study.

Journal: Thrombosis and Haemostasis

November/11/2012

Abstract

Cancer increases the risk of venous thromboembolism (VTE). Here, we investigated the contribution of microparticle (MP)-dependent procoagulant activity to the prothrombotic state in these patients. In 43 cancer patients without VTE at study entry and 22 healthy volunteers, markers of in vivo and MP-dependent coagulation were measured and patients were prospectively followed for six months for the development of VTE. Procoagulant activity of MPs was measured in vitro using a tissue factor (TF)-independent phospholipid dependent test, a factor Xa-generation assay with and without anti-TF, and a fibrin generation test (FGT) with and without anti-factor VII(a). Markers of in vivo coagulation activation and total number of MPs at baseline were significantly elevated in cancer patients compared to controls (F1+2 246 vs. 156 pM, thrombin-antithrombin complexes 4.1 vs. 3.0 mg/l, D-dimer 0.76 vs. 0.22 mg/l and 5.53 x 10⁶ vs. 3.37 x 10⁶ MPs/ml). Five patients (11.6%) developed VTE. Patients with VTE had comparable levels of coagulation activation markers and phospholipid-dependent MP procoagulant activity. However, median TF-mediated Xa-generation (0.82 vs. 0.21 pg/ml, p=0.016) and median VIIa-dependent FGT (13% vs. 0%, p=0.036) were higher in the VTE group compared with the non-VTE group. In this exploratory study the overall hypercoagulable state in cancer patients was not associated directly with the MP phospholipid-dependent procoagulant activity. However, in the patients who developed VTE within six months when compared to those who did not, an increased MP procoagulant activity was present already at baseline, suggesting this activity can be used to predict VTE.

Authors

Frederiek van Doormaal; Ankie Kleinjan; René J Berckmans; Nigel Mackman; David Manly; Pieter W Kamphuisen+4 authors

Publication

Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study.

Journal: American Journal of Medicine

March/8/2004

Abstract

OBJECTIVE

To evaluate a diagnostic strategy for pulmonary embolism that combined clinical assessment, plasma D-dimer measurement, lower limb venous ultrasonography, and helical computed tomography (CT).

METHODS

A cohort of 965 consecutive patients presenting to the emergency departments of three general and teaching hospitals with clinically suspected pulmonary embolism underwent sequential noninvasive testing. Clinical probability was assessed by a prediction rule combined with implicit judgment. All patients were followed for 3 months.

RESULTS

A normal D-dimer level (<500 microg/L by a rapid enzyme-linked immunosorbent assay) ruled out venous thromboembolism in 280 patients (29%), and finding a deep vein thrombosis by ultrasonography established the diagnosis in 92 patients (9.5%). Helical CT was required in only 593 patients (61%) and showed pulmonary embolism in 124 patients (12.8%). Pulmonary embolism was considered ruled out in the 450 patients (46.6%) with a negative ultrasound and CT scan and a low-to-intermediate clinical probability. The 8 patients with a negative ultrasound and CT scan despite a high clinical probability proceeded to pulmonary angiography (positive: 2; negative: 6). Helical CT was inconclusive in 11 patients (pulmonary embolism: 4; no pulmonary embolism: 7). The overall prevalence of pulmonary embolism was 23%. Patients classified as not having pulmonary embolism were not anticoagulated during follow-up and had a 3-month thromboembolic risk of 1.0% (95% confidence interval: 0.5% to 2.1%).

CONCLUSIONS

A noninvasive diagnostic strategy combining clinical assessment, D-dimer measurement, ultrasonography, and helical CT yielded a diagnosis in 99% of outpatients suspected of pulmonary embolism, and appeared to be safe, provided that CT was combined with ultrasonography to rule out the disease.

Authors

Arnaud Perrier; Pierre-Marie Roy; Drahomir Aujesky; Isabelle Chagnon; Nigel Howarth; Anne-Laurence Gourdier+5 authors

Publication

Purification and partial characterization of the Mr 30,000 integral membrane protein associated with the erythrocyte Rh(D) antigen.

Journal: Journal of Biological Chemistry

January/28/1988

Abstract

Erythrocytes bearing the Rh(D) antigen have an Mr 30,000 integral membrane protein which can be surface-labeled with 125I and can be quantitatively immunoprecipitated from Triton X-100-solubilized spectrin-depleted membrane vesicles. The 125I-labeled Rh(D)-associated protein was purified to radiochemical homogeneity from membrane skeletons solubilized in sodium dodecyl sulfate and urea by hydroxylapatite chromatography, gel filtration, and preparative polyacrylamide gel electrophoresis. The Rh(D)-associated protein was purified nearly 200-fold from 2 units of erythrocytes from DD individuals by employing similar methods on a large scale using the purified 125I-labeled Rh(D)-associated protein as a tracer. The product appeared to be greater than 95% pure and migrated as a diffuse band of Mr approximately 30,000-32,000 on silver-stained sodium dodecyl sulfate electrophoresis gels poured from 12% acrylamide. It is estimated that the Rh(D)-associated protein makes up approximately 0.5% of the original membrane protein. When concentrated, partially purified Rh(D)-associated protein forms dimers and larger oligomers which are stable in sodium dodecyl sulfate and urea. The Rh(D)-associated protein was protected from degradation when intact erythrocytes or inside out membrane vesicles were enzymatically digested. These studies indicate that the Mr 30,000 protein associated with the Rh(D) antigen is linked to the membrane skeleton, resides within the lipid bilayer with minimal extra- or intracellular protrusions, exists normally as an oligomer, and can be purified in denatured form.

Authors

P Agre; A M Saboori; A Asimos; B L Smith

Publication

A novel and rapid whole-blood assay for D-dimer in patients with clinically suspected deep vein thrombosis.

Journal: Circulation

May/3/1995

Abstract

BACKGROUND

The clinical utility of using a novel whole blood assay for D-dimer (SimpliRED), alone or in combination with impedance plethysmography (IPG), was investigated in a two-center, prospective cohort study of 214 consecutive patients with clinically suspected deep vein thrombosis (DVT).

RESULTS

All patients underwent the SimpliRED D-dimer assay, contrast venography, and IPG. According to the results of venography, 43 patients had proximal DVT (popliteal and/or more proximal veins), 10 had isolated calf DVT, and 161 had DVT ruled out. The D-dimer had a sensitivity of 93% for proximal DVT and of 70% for calf DVT, an overall specificity of 77%, and a negative predictive value of 98% for proximal DVT. The sensitivity and specificity of IPG for proximal DVT were 67% and 96%, respectively. When analyzed in combination with the IPG results, it was determined that (1) the combination of a negative D-dimer and a normal IPG had a negative predictive value of 97% for all DVT and of 99% for proximal DVT and occurred in 58% of patients (likelihood ratio, 0.1) and (2) the combination of a positive D-dimer and an abnormal IPG had a positive predictive value of 93% for any DVT and of 90% for proximal DVT and occurred in 14% of patients (likelihood ratio, 42.6). When the D-dimer and IPG results were discordant, it was not possible to exclude or diagnose DVT reliably; discordant results occurred in 28% of patients.

CONCLUSIONS

The SimpliRED D-dimer assay, which can be performed and interpreted at the bedside within 5 minutes, has great potential in patients with clinically suspected DVT, especially for ruling out DVT, and is complementary to IPG. The assay should be evaluated in large clinical management studies.

Authors

P S Wells; P Brill-Edwards; P Stevens; A Panju; A Patel; J Douketis+4 authors

Publication

Hemostatic function and progressing ischemic stroke: D-dimer predicts early clinical progression.

Journal: Stroke

November/15/2004

Abstract

OBJECTIVE

Early clinical progression of ischemic stroke is common and is associated with increased risk of death and dependency. We hypothesized that activation of the coagulation system is an important contributor in some cases of deterioration. We aimed to characterize alterations in circulating hemostatic markers in patients with progressing stroke.

METHODS

Consecutive acute ischemic stroke admissions were recruited. Progressing stroke was defined by deterioration in components of the Scandinavian Stroke Scale. Hemostatic markers (coagulation factors VIIc, VIIIc, and IXc, prothrombin fragments 1+2 [F1+2], thrombin-antithrombin complexes [TAT], D-dimer, fibrinogen, von Willebrand factor [vWF] and tissue plasminogen activator) were measured within 24 hours of symptom recognition.

RESULTS

Fifty-four (25%) of the 219 patients met criteria for progressing stroke. F1+2 (median 1.28 versus 1.06 nmol/L, P=0.01), TAT (5.28 versus 4.07 microg/L, P<0.01), D-dimer (443 versus 194 ng/mL, P<0.001) and vWF (216 versus 198 IU/dL, P<0.05) levels were higher in these patients than in stable/improving patients. In logistic regression analysis, with all important clinical and laboratory variables included, only natural log D-dimer (odds ratio [OR]: 1.87; 95% confidence interval [CI]: 1.38 to 2.54; P=0.0001) and mean arterial blood pressure (OR: 1.26 per 10 mm Hg change; 95% CI: 1.05 to 1.51; P=0.01) remained independent predictors of progressing stroke.

CONCLUSIONS

There is evidence of excess thrombin generation and fibrin turnover in patients with progressing ischemic stroke. Measurement of D-dimer levels can identify patients at high risk for stroke progression. Further research is required to determine whether such patients benefit from acute interventions aimed at modifying hemostatic function.

Authors

Mark Barber; Peter Langhorne; Ann Rumley; Gordon D O Lowe; David J Stott

Publication

The effect of tranexamic acid on local and plasma fibrinolysis during total knee arthroplasty.

Journal: Thrombosis Research

May/19/1997

Abstract

The aim of the present study was to investigate aspects of coagulation and fibrinolysis during knee arthroplasties in order to find out. 1. whether an increased fibrinolysis is correlated to an increased blood loss 2. whether there is a difference in markers for coagulation and fibrinolysis in peripheral venous blood compared to those in blood from the wounds 3. whether the administration of tranexamic acid modifies the fibrinolytic response. Twenty-four patients were included. Twelve patients were given tranexamic acid intravenously at the end of the operation. The dose was repeated three hours later. The other 12 patients were given an equivalent amount of placebo. The administration was randomised and double-blind. Levels of prothrombin fragments 1 + 2, D-dimers, plasminogen, alpha 2-antiplasmin, tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI-1) in venous blood were investigated just before the operation, at the end of the operation and three hours later. At the end of the operation blood for analysis was also drawn from the wound. Coagulation and fibrinolysis was activated during and after surgery. The activation was significantly higher in blood from the wounds than in peripheral venous blood. We found no direct correlation between the degree of fibrinolysis and blood loss. The administration of tranexamic acid reduced fibrinolysis in the wounds but not in peripheral venous blood. The postoperative blood loss was reduced by half.

Authors

G Benoni; S Lethagen; H Fredin

Publication

Tranexamic acid attenuates inflammatory response in cardiopulmonary bypass surgery through blockade of fibrinolysis: a case control study followed by a randomized double-blind controlled trial.

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Journal: Critical Care

April/13/2008

Abstract

BACKGROUND

Extracorporeal circulation induces hemostatic alterations that lead to inflammatory response (IR) and postoperative bleeding. Tranexamic acid (TA) reduces fibrinolysis and blood loss after cardiopulmonary bypass (CPB). However, its effects on IR and vasoplegic shock (VS) are not well known and elucidating these effects was the main objective of this study.

METHODS

A case control study was carried out to determine factors associated with IR after CPB. Patients undergoing elective CPB surgery were randomly assigned to receive 2 g of TA or placebo (0.9% saline) before and after intervention. We performed an intention-to-treat analysis, comparing the incidence of IR and VS. We also analyzed several biological parameters related to inflammation, coagulation, and fibrinolysis systems. We used SPSS version 12.2 for statistical purposes.

RESULTS

In the case control study, 165 patients were studied, 20.6% fulfilled IR criteria, and the use of TA proved to be an independent protective variable (odds ratio 0.38, 95% confidence interval 0.18 to 0.81; P < 0.01). The clinical trial was interrupted. Fifty patients were randomly assigned to receive TA (24) or placebo (26). Incidence of IR was 17% in the TA group versus 42% in the placebo group (P = 0.047). In the TA group, we observed a significant reduction in the incidence of VS (P = 0.003), the use of norepinephrine (P = 0.029), and time on mechanical ventilation (P = 0.018). These patients showed significantly lower D-dimer, plasminogen activator inhibitor 1, and creatine-kinase levels and a trend toward lower levels of soluble tumor necrosis factor receptor and interleukin-6 within the first 24 hours after CPB.

CONCLUSIONS

The use of TA attenuates the development of IR and VS after CPB.

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Authors

Juan J Jimenez; Jose L Iribarren; Leonardo Lorente; Jose M Rodriguez; Domingo Hernandez; Ibrahim Nassar+5 authors

Publication

Historically controlled comparison of glucocorticoids with or without tocilizumab versus supportive care only in patients with COVID-19-associated cytokine storm syndrome: results of the CHIC study

Journal: Annals of the Rheumatic Diseases

July/28/2020

Abstract

Objectives: To prospectively investigate in patients with severe COVID-19-associated cytokine storm syndrome (CSS) whether an intensive course of glucocorticoids with or without tocilizumab accelerates clinical improvement, reduces mortality and prevents invasive mechanical ventilation, in comparison with a historic control group of patients who received supportive care only.

Methods: From 1 April 2020, patients with COVID-19-associated CSS, defined as rapid respiratory deterioration plus at least two out of three biomarkers with important elevations (C-reactive protein >100 mg/L; ferritin >900 µg/L; D-dimer >1500 µg/L), received high-dose intravenous methylprednisolone for 5 consecutive days (250 mg on day 1 followed by 80 mg on days 2-5). If the respiratory condition had not improved sufficiently (in 43%), the interleukin-6 receptor blocker tocilizumab (8 mg/kg body weight, single infusion) was added on or after day 2. Control patients with COVID-19-associated CSS (same definition) were retrospectively sampled from the pool of patients (n=350) admitted between 7 March and 31 March, and matched one to one to treated patients on sex and age. The primary outcome was ≥2 stages of improvement on a 7-item WHO-endorsed scale for trials in patients with severe influenza pneumonia, or discharge from the hospital. Secondary outcomes were hospital mortality and mechanical ventilation.

Results: At baseline all patients with COVID-19 in the treatment group (n=86) and control group (n=86) had symptoms of CSS and faced acute respiratory failure. Treated patients had 79% higher likelihood on reaching the primary outcome (HR: 1.8; 95% CI 1.2 to 2.7) (7 days earlier), 65% less mortality (HR: 0.35; 95% CI 0.19 to 0.65) and 71% less invasive mechanical ventilation (HR: 0.29; 95% CI 0.14 to 0.65). Treatment effects remained constant in confounding and sensitivity analyses.

Conclusions: A strategy involving a course of high-dose methylprednisolone, followed by tocilizumab if needed, may accelerate respiratory recovery, lower hospital mortality and reduce the likelihood of invasive mechanical ventilation in COVID-19-associated CSS.

Keywords: biological therapy; cytokines; epidemiology; glucocorticoids.

Authors

Sofia Ramiro; Rémy Mostard; César Magro-Checa; Christel van Dongen; Tom Dormans; Jacqueline Buijs+8 authors

Publication

Proteolytic activation and function of the cytokine Spätzle in the innate immune response of a lepidopteran insect, Manduca sexta.

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Journal: The FEBS journal

January/31/2010

Abstract

The innate immune response of insects includes induced expression of genes encoding a variety of antimicrobial peptides. The signaling pathways that stimulate this gene expression have been well characterized by genetic analysis in Drosophila melanogaster, but are not well understood in most other insect species. One such pathway involves proteolytic activation of a cytokine called Spätzle, which functions in dorsal-ventral patterning in early embryonic development and in the antimicrobial immune response in larvae and adults. We have investigated the function of Spätzle in a lepidopteran insect, Manduca sexta, in which hemolymph proteinases activated during immune responses have been characterized biochemically. Two cDNA isoforms for M. sexta Spätzle-1 differ because of alternative splicing, resulting in a 10 amino acid residue insertion in the pro-region of proSpätzle-1B that is not present in proSpätzle-1A. The proSpätzle-1A cDNA encodes a 32.7 kDa polypeptide that is 23% and 44% identical to D. melanogaster and Bombyx mori Spätzle-1, respectively. Recombinant proSpätzle-1A was a disulfide-linked homodimer. M. sexta hemolymph proteinase 8 cleaved proSpätzle-1A to release Spätzle-C108, a dimer of the C-terminal 108 residue cystine-knot domain. Injection of Spätzle-C108, but not proSpätzle-1A, into larvae stimulated expression of several antimicrobial peptides and proteins, including attacin-1, cecropin-6, moricin, lysozyme, and the immunoglobulin domain protein hemolin, but did not significantly affect the expression of two bacteria-inducible pattern recognition proteins, immulectin-2 and beta-1,3-glucan recognition protein-2. The results of this and other recent studies support a model for a pathway in which the clip-domain proteinase pro-hemolymph proteinase 6 becomes activated in plasma upon exposure to Gram-negative or Gram-positive bacteria or to beta-1,3-glucan. Hemolymph proteinase 6 then activates pro-hemolymph proteinase 8, which in turn activates Spätzle-1. The resulting Spätzle-C108 dimer is likely to function as a ligand to activate a Toll pathway in M. sexta as a response to a wide variety of microbial challenges, stimulating a broad response to infection. Structured digital abstract * MINT-7295125: Spätzle 1A (uniprotkb:C8BMD1) and Spätzle 1A (uniprotkb:C8BMD1) bind (MI:0407) by comigration in gel electrophoresis (MI:0807).

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Authors

Chunju An; Haobo Jiang; Michael R Kanost

Publication

Direct calcium binding results in activation of brain serine racemase.

Journal: Journal of Biological Chemistry

September/15/2002

Abstract

Serine racemase (SR) is a brain enzyme present in glial cells, where it isomerizes L-serine into D-serine that, in turn, diffuses and coactivates the N-methyl-D-aspartate receptor through the binding to the so-called "glycine site." We have developed a method for the slow expression of SR in a eukaryotic vector that permits the correct insertion of the prosthetic group into the active site, rendering functional SR with a K(m) toward L-serine of 4.8 mm. Divalent cations such as calcium or manganese were necessary for complete enzyme activity, whereas the presence of chelators such as EDTA completely inhibited the enzyme. Moreover, direct binding of calcium to SR was evidenced using (45)Ca(2+). Gel filtration of the recombinant SR revealed the protein to be in a dimer-tetramer equilibrium. The addition of EDTA to a calcium-saturated serine racemase evokes a profound conformational change, as monitored by both fluorescence and circular dichroism techniques. Fluorescence titration allowed us to calculate a binding constant for calcium of 6.2 microm. Reagents that react with sulfhydryl groups, such as cystamine, were potent inhibitors of SR, in a clear reflection that one or more cysteine residues are important for enzyme activity. Additionally, 16 serine analogues were tested as a putative SR substrate or inhibitors. Significant inhibition was only observed for L-Ser-O-sulfate, L-cycloserine, and L-cysteine. Finally, activation of brain SR as a result of the changes in calcium concentration was studied in primary astrocytes. Treatment of astrocytes with the calcium ionophore, as well as with compounds that augment the intracellular calcium levels such as glutamate or kainate led to an increase in the amount of d-serine present in the extracellular medium. These results suggest that there might be a glutamatergic-mediated regulation of SR activity by intracellular calcium concentration.

Authors

Silas P Cook; Ismael Galve-Roperh; Alvaro Martínez del Pozo; Ignacio Rodríguez-Crespo

Publication

Association of localized intravascular coagulopathy with venous malformations.

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Journal: Archives of dermatology

August/13/2008

Abstract

OBJECTIVE

To determine which venous malformations (VMs) are at risk for coagulopathy. Venous malformations are slow-flow vascular malformations present at birth, and localized intravascular coagulopathy (LIC) causes pain and thrombosis within a lesion and severe bleeding during surgical procedures.

METHODS

Prospective convenience sample accrued from 2 multidisciplinary sites in Brussels, Belgium, and Caen, France.

METHODS

The study population comprised 140 patients with clinical data and coagulation parameters. Magnetic resonance imaging was performed for 110 patients.

METHODS

Measurement of D-dimer levels.

RESULTS

Of the 140 participants, 59 (42%) showed high D-dimer levels, 36 (61%) of whom had levels higher than 1.0 microg/mL. Six of the participants had low fibrinogen levels. In univariate analysis, large surface, presence of palpable phleboliths, and truncal localization were associated with high D-dimer levels. In the multivariate analysis, only large surface area and presence of phleboliths remained independently associated with high D-dimer levels. Severe LIC, characterized by concomitant low fibrinogen level, was associated with extensive venous malformations of the extremities.

CONCLUSIONS

Localized intravascular coagulopathy is statistically significantly associated with large and/or deep venous malformations that affect any location, which can have a palpable phlebolith. These patients are at risk of local pain due to thrombosis. Lesions with elevated D-dimer levels associated with low fibrinogen levels (severe LIC) commonly affect an extremity and have a high risk of hemorrhage. Low-molecular-weight heparin can be used both to treat the pain caused by LIC and to prevent decompensation of severe LIC to disseminated intravascular coagulopathy.

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Authors

Anne Dompmartin; Aurélie Acher; Pascal Thibon; Sébastien Tourbach; Cédric Hermans; Véronique Deneys+7 authors

Publication

Factors associated with death outcome in patients with severe coronavirus disease-19 (COVID-19): a case-control study

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Journal: International Journal of Medical Sciences

June/17/2020

Abstract

Rationale: Up to date, the exploration of clinical features in severe COVID-19 patients were mostly from the same center in Wuhan, China. The clinical data in other centers is limited. This study aims to explore the feasible parameters which could be used in clinical practice to predict the prognosis in hospitalized patients with severe coronavirus disease-19 (COVID-19). Methods: In this case-control study, patients with severe COVID-19 in this newly established isolation center on admission between 27 January 2020 to 19 March 2020 were divided to discharge group and death event group. Clinical information was collected and analyzed for the following objectives: 1. Comparisons of basic characteristics between two groups; 2. Risk factors for death on admission using logistic regression; 3. Dynamic changes of radiographic and laboratory parameters between two groups in the course. Results: 124 patients with severe COVID-19 on admission were included and divided into discharge group (n=35) and death event group (n=89). Sex, SpO2, breath rate, diastolic pressure, neutrophil, lymphocyte, C-reactive protein (CRP), procalcitonin (PCT), lactate dehydrogenase (LDH), and D-dimer were significantly correlated with death events identified using bivariate logistic regression. Further multivariate logistic regression demonstrated a significant model fitting with C-index of 0.845 (p<0.001), in which SpO2≤89%, lymphocyte≤0.64×109/L, CRP>77.35mg/L, PCT>0.20μg/L, and LDH>481U/L were the independent risk factors with the ORs of 2.959, 4.015, 2.852, 3.554, and 3.185, respectively (p<0.04). In the course, persistently lower lymphocyte with higher levels of CRP, PCT, IL-6, neutrophil, LDH, D-dimer, cardiac troponin I (cTnI), brain natriuretic peptide (BNP), and increased CD4+/CD8+ T-lymphocyte ratio and were observed in death events group, while these parameters stayed stable or improved in discharge group. Conclusions: On admission, the levels of SpO2, lymphocyte, CRP, PCT, and LDH could predict the prognosis of severe COVID-19 patients. Systematic inflammation with induced cardiac dysfunction was likely a primary reason for death events in severe COVID-19 except for acute respiratory distress syndrome.

Keywords: COVID-19; Critical care; Prognosis; Radiography; Risk factors.

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Flowchart of inclusion of the patients.

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ROC curve of multivariate logistic regression. Note: C-index of the predicted probability was...

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Typical radiographic aggravation manifestations. Note: A-C from a patient in discharge group...

Authors

Feng Pan; Lian Yang; Yuncheng Li; Bo Liang; Lin Li; Tianhe Ye+5 authors

Publication

Total synthesis and structural revision of the piperarborenines via sequential cyclobutane C-H arylation.

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Journal: Journal of the American Chemical Society

March/19/2012

Abstract

A strategy for the construction of unsymmetrical cyclobutanes using C-H functionalization logic is demonstrated in the total synthesis of piperarborenine B and piperarborenine D (reported structure). These syntheses feature a new preparation of cis-cyclobutane dicarboxylates from commercially available coumalate starting materials and a divergent approach to the controlled cis or trans installation of the two distinct aryl rings found in the natural products using the first example of cyclobutane C-H arylation. The structure of piperarborenine D is reassigned to a head-to-head dimer, which was synthesized using an intramolecular [2+2] photocycloaddition strategy.

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Authors

Will R Gutekunst; Phil S Baran