bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal of N-Linked Glycosylation Sites in the V1 Region of Simian Immunodeficiency Virus gp120 Results in Redirection of B-Cell Responses to V3
Authors: Cole Kelly Stefano , Steckbeck Jonathan D. , Rowles Jennifer L. , Desrosiers Ronald C. , Montelaro Ronald C. 
Published: January 2004

ABSTRACTOne mechanism of immune evasion utilized by human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) envelope glycoproteins is the presence of a dense carbohydrate shield. Accumulating evidence from in vitro and in vivo experiments suggests that alterations in N-linked glycosylation of SIV gp120 can enhance host humoral immune responses that may be involved in immune control. The present study was designed to determine the ability of glycosylation mutant viruses to redirect antibody responses to shielded envelope epitopes. The influence of glycosylation on the maturation and specificity of antibody responses elicited by glycosylation mutant viruses containing mutations of specific N-linked sites in and near the V1 and V2 regions of SIVmac239 gp120 was determined. Results from these studies demonstrated a remarkably similar maturation of antibody responses to native, fully glycosylated envelope proteins. However, analyses of antibodies to defined envelope domains revealed that mutation of glycosylation sites in V1 resulted in increased antibody recognition to epitopes in V1. In addition, we demonstrated for the first time that mutation of glycosylation sites in V1 resulted in a redirection of antibody responses to the V3 loop. Taken together, these results demonstrate that N-linked glycosylation is a determinant of SIV envelope B-cell immunogenicity in addition to in vitro antigenicity. In addition, our results demonstrate that the absence of N-linked carbohydrates at specific sites can influence the exposure of epitopes quite distant in the linear sequence.
Cross-Genotype Immunity to Hepatitis C Virus
Authors: Lanford Robert E. , Guerra Bernadette , Chavez Deborah , Bigger Catherine , Brasky Kathleen M. , Wang Xiao-Hong , Ray Stuart C. , Thomas David L. 
Published: January 2004

ABSTRACTRecent studies in humans and chimpanzees suggest that immunity can be induced to diminish the incidence of chronic hepatitis C virus (HCV) infection. However, the immunity that promotes viral recovery is poorly understood, and whether the breadth of this adaptive immunity is sufficient to overcome the substantial intergenotype antigenic diversity represents a final obstacle to demonstrating the feasibility of vaccine development. Here we demonstrate that recovery from a genotype 1 HCV infection protects chimpanzees against infection with representatives of other genotypes that exhibit up to 30% divergence at the amino acid level, including challenges with genotype 4, a mixture of genotypes 2 and 3, and a complex inoculum containing genotypes 1, 2, 3, and 4. In each instance, the level and duration of viremia were markedly reduced in comparison to the primary infection in the same animal. The data indicate that epitopes conserved between genotypes must play an essential role in immunity. The inocula used in the rechallenge studies induced typical primary infection profiles in naïve chimpanzees. Rechallenge infections were associated with rapid increases in the intrahepatic transcripts of interferon-stimulated genes, even in animals exhibiting apparent sterilizing immunity. Protective immunity was often associated with an early increase in gamma interferon transcripts in the liver and increases in intrahepatic transcripts of Mig, a T-cell chemokine that is a gamma interferon response gene. These studies are the first to show that cross-genotype immunity can be induced to HCV, demonstrating the feasibility of developing a vaccine protective against all HCV strains.
The Movement Protein of
Cowpea Mosaic Virus
Binds GTP and Single-Stranded Nucleic Acid In Vitro
Authors: Carvalho C. M. , Pouwels J. , van Lent J. W. M. , Bisseling T. , Goldbach R. W. , Wellink J. 
Published: January 2004

ABSTRACT

The movement protein (MP) of
Cowpea mosaic virus
forms tubules in plasmodesmata to enable the transport of mature virions. Here it is shown that the MP is capable of specifically binding riboguanosine triphosphate and that mutational analysis suggests that GTP binding plays a role in the targeted transport of the MP. Furthermore, the MP is capable of binding both single-stranded RNA and single-stranded DNA in a non-sequence-specific manner, and the GTP- and RNA-binding sites do not overlap.
Ability of Wild-Type and Mutant Lysyl-tRNA Synthetase To Facilitate tRNA
Lys
Incorporation into Human Immunodeficiency Virus Type 1
Authors: Cen Shan , Javanbakht Hassan , Niu Meijuan , Kleiman Lawrence 
Published: January 2004

ABSTRACT

The major human tRNA
Lys
isoacceptors, tRNA1,2Lys and tRNA3Lys, are selectively packaged into human immunodeficiency virus type 1 (HIV-1) during assembly, where tRNA3Lys acts as a primer for reverse transcription. Lysyl-tRNA synthetase (LysRS) is also incorporated into HIV-1, independently of tRNA
Lys
, via its interaction with Gag, and it is a strong candidate for being the signal that specifically targets tRNA
Lys
for viral incorporation. Expression of exogenous wild-type LysRS in cells results in an approximately twofold increase in the viral packaging of both LysRS and tRNA
Lys
. Herein, we show that this increase in tRNA
Lys
incorporation into virions is dependent upon the ability of LysRS to bind to tRNA
Lys
but not upon its ability to aminoacylate the tRNA
Lys
. COS7 cells were cotransfected with plasmids coding for both HIV-1 and either wild-type or mutant human LysRS, all of which are incorporated into virions with similar efficiency. However, N-terminally truncated LysRS, which binds poorly to tRNA
Lys
, does not increase tRNA
Lys
packaging into viruses, while C-terminally truncated LysRS, which binds to but does not aminoacylate tRNA
Lys
, still facilitates an increase in tRNA
Lys
packaging into virions.
SUBLATTICES OF LATTICES OF ORDER-CONVEX SETS, II.
Authors: SEMENOVA MARINA , WEHRUNG FRIEDRICH 
Published: January 2004

For a positive integer n, we denote by SUB (respectively, SUBn) the class of all lattices that can be embedded into the lattice Co(P) of all order-convex subsets of a partially ordered set P (respectively, P of length at most n). We prove the following results:(1) SUBnis a finitely based variety, for any n≥1.(2) SUB2is locally finite.(3) A finite atomistic lattice L without D-cycles belongs to SUB if and only if it belongs to SUB2; this result does not extend to the nonatomistic case.(4) SUBnis not locally finite for n≥3.
FREE MONOID THEORY: MAXIMALITY AND COMPLETENESS IN ARBITRARY SUBMONOIDS
Authors: NÉRAUD JEAN , SELMI CARLA 
Published: January 2004

In this paper, we discuss the different notions of local topological density for subsets of the free monoid A*. We introduce the notion of weak completeness for a set X, relatively to an arbitrary submonoid M of A*. For the so-called strongly M-thin codes, we establish that weak completeness is equivalent to maximality in M. This constitutes a new generalization of a famous result due to Schützenberger.
Thrombin binding to GPIbα induces integrin αIIbβ3 dependent platelet adhesion to fibrin in ex vivo flowing whole blood
Authors: Reigner Sylvie C. , Steiner Beat , Dubois Christophe , Riederer Markus 
Published: January 2004

SummaryWe have investigated the role of the thrombin/GPIbα interaction in the adhesion of platelets to fibrin in a whole blood ex vivo perfusion model at a shear rate of 280 s-1. Blood was perfused through parallel-plate chambers containing coverslips coated with cells expressing tissue factor, leading to the generation of thrombin and thus, deposition of fibrin onto the exposed cells. Adhesion of platelets to fibrin and thrombus growth were analyzed. Interestingly, when GPIbα was removed from the platelet surface by action of mocarhagin, platelet adhesion on fibrin was inhibited. Furthermore, a monoclonal antibody, VM16d, directed against the thrombin binding site on GPIbα also inhibited platelet adhesion on fibrin, showing the importance of the thrombin/GPIbα interaction. We then looked at the involvement of αIIbβ3 and showed that platelet adhesion and thrombus growth on fibrin were inhibited by the dodecapeptide, whereas lamifiban only inhibited the growth of the platelet thrombus. These results indicated that binding of thrombin to GPIbα induced an intracellular signaling leading to the interaction of the platelet integrin αIIbβ3 with the fibrindodecapeptide sequence.
Coagulopathy of sepsis
Authors: Dempfle Carl-Erik 
Published: January 2004

SummaryDisseminated intravascular coagulation (DIC) is a common phenomenon in patients with sepsis, but the clinical implications of this condition are not clear. Clinical trials with coagulation inhibitors have failed to show a significant benefit concerning survival. DIC is primarily a laboratory diagnosis, based on the combination of elevated fibrin-related markers (FRM), with decreased procoagulant factors and platelets. Non-overt DIC is observed in most patients with sepsis, whereas overt DIC is less frequent. Patients with overt DIC may display consumption coagulopathy and purpura fulminans. Consumption coagulopathy is a bleeding disorder caused by low levels of platelets and procoagulant factors associated with massive coagulation activation. Purpura fulminans is caused by widespread microvascular thrombosis, resulting in tissue necrosis. Treatment with drotrecogin alfa (activated) improves survival and other outcome parameters in severe sepsis, including a subgroup of patients fulfilling the laboratory criteria of overt DIC. No randomized trials demonstrating effective therapies in consumption coagulopathy have been published. Bleeding patients with consumption coagulopathy are most frequently treated with platelet transfusions and various plasma products including fresh frozen plasma and coagulation factor concentrates. Based on case reports, treatment with drotrecogin alfa (activated) or substitution of protein C have been recommended for adjuvant treatment of sepsis-related purpura fulminans.
Relationships between plasma adiponectin and blood cells, hepatopancreatic enzymes in women
Authors: Namioka Katsuhiko , Katayose Shinji , Matsubara Miyao 
Published: January 2004

SummaryAdiponectin, which is secreted specifically from adipocyte, is thought to play a key role in the metabolic syndrome. We studied the associations of plasma adiponectin concentrations with blood cells and hepatopancreatic enzymes in 339 women aged 54.0 ± 0.8 (mean ± SE) years. Plasma adiponectin before and after adjustment for body composition or calculated insulin resistance increased in slight anemic women (372.6 ± 2.6 ×104/mm3) compared with non-anemic subjects (471.1 ± 1.7) (all p < 0.0001), and were inversely associated with red blood cells (RBC), hemoglobin, hematocrit, white blood cells and platelet values (p < 0.0001 ∼ 0.02), independent of age, diastolic blood pressure, body mass index, serum triglyceride, insulin resistance or blood urea nitrogen. Age and adiponectin/body fat mass (%) were negative, and blood pressure and insulin resistance were positive significant independent determinants of RBC in stepwise regression analysis. Moreover, adiponectin before and after adjustment were inversely associated with serum ALAT,γGTP and ChE, and positively with amylase levels (p < 0.0001 ∼ 0.02). These results indicate the possibility that increased adiponectin may contribute to the suppressive bone marrow function in vivo. Combined with the leptin’s data, adipocyte derived proteins were related to the hematopoiesis, therefore it has shown the possible existence of adipose tissue/ bone marrow function linkage more clearly. Furthermore, hepatopancreatic enzyme associations with this protein may indicate the possibility that adiponectin will regulate the hepatopancreatic function in health and disease.
Plasma MMP–2 and MMP–9 and their inhibitors TIMP-1 and TIMP-2 during human orthotopic liver transplantation
Authors: Kuyvenhoven Johan , Molenaar Quintus , Veldman Marietta , Palareti Gualtiero , Legnani Cristina , Moolenburgh Sanne , Terpstra Onno , Lamers Cornelis , van Hoek Bart , Porte Robert , Verspaget Hein 
Published: January 2004

SummaryUncontrolled activation of matrix metalloproteinases (MMPs) can result in tissue injury and inflammation, yet little is known about the activation of MMPs during orthotopic liver transplantation (OLT). OLT is associated with increased fibrinolytic activity due to elevated plasmin generation. The serine-protease plasmin not only causes degradation of fibrin clots but is also thought, amongst others, to play a role in the activation of some matrix metalloproteinases. We therefore studied the evolution of MMP-2 and -9 plasma concentrations during OLT and the effect of serine-protease inhibition by aprotinin on the level and activation of these MMPs. In a group of 24 patients who participated in a randomized, double-blind, placebo-controlled study we determined serial MMP-2 and MMP-9 plasma levels during transplantation using ELISA (total MMP), activity assays (activatable MMP) and zymography. In addition, the MMP-inhibitors TIMP-1 and TIMP-2 were assessed by ELISA. The putative regulating factors tumor necrosis factor alpha (TNF-α) and tissue-type plasminogen activator (t-PA) were assessed as well. Patients were administered high-dose aprotinin, regular-dose aprotinin or placebo during surgery. Plasma TIMP-1, TIMP-2 and MMP-2 level gradually decreased during transplantation. Approximately twothirds of total MMP-2 appeared to be in its activatable proMMP form. No release of MMP-2 from the graft could be detected. In contrast, plasma levels of MMP-9 increased sharply during the anhepatic and postreperfusion periods. Peak MMP-9 levels of about eight times above baseline were found at 30 minutes after reperfusion. Most MMP-9 appeared to be in its active/inhibitorcomplexed form. No significant differences were observed between the three treatment groups. However, in patients with more severe ischemia/reperfusion (I/R) injury the MMP-9 concentration, particularly of the active/inhibitor-complexed form, remained high at 120 minutes postreperfusion compared to patients with no or mild I/R injury. The decrease in plasma levels of MMP-2,TIMP-1 and TIMP-2 during OLT occurred irrespective of the severity of the I/R injury. There was a significant correlation between MMP-9 and t-PA levels, but not with TNF-α. In conclusion, OLT is associated with a sharp increase of MMP-9 during the anhepatic and postreperfusion periods, which coincided with the changes in t-PA. MMP-2, TIMP-1 and TIMP-2 gradually decreased during OLT. The composition of these MMPs was not altered by the use of aprotinin, suggesting that serine–protease/plasmin-independent pathways are responsible for MMP regulation during OLT. In addition, only MMP-9 seems to be involved in I/R injury during human liver transplantation.
Sustained elevated amounts of circulating procoagulant membrane microparticles and soluble GPV after acute myocardial infarction in diabetes mellitus
Authors: Morel Olivier , Hugel Bénédicte , Jesel Laurence , Lanza François , Douchet Marie-Pierre , Zupan Michel , Chauvin Michel , Cazenave Jean-Pierre , Freyssinet Jean-Marie , Toti Florence 
Published: January 2004

SummaryDuring myocardial infarction (MI), platelet activation and endothelial apoptosis are responsible for the release of procoagulant membrane-derived microparticles (MP) in the blood flow. MP prothrombotic and proinflammatory properties may be crucial for coronary prognosis. Elevated amounts of circulating procoagulant MP were described in diabetes mellitus (DM), and could be of particular significance in a MI context. We evaluated the prothrombotic status of DM and non-DM (NDM) patients at days 1 and 6 after MI, by measurement of circulating procoagulant MP and soluble GPV (sGPV), the platelet glycoprotein V major fragment released upon thrombin cleavage. Variations were compared to values measured in healthy volunteers (HV). Procoagulant MP were captured onto insolubilized annexin V and quantified by prothrombinase assay. Their cellular origin was assessed. With respect to HV, the levels of procoagulant MP detected at D1 and D6 were elevated in DM and NDM, MP being significantly higher in DM vs. NDM. The high amounts of platelet-derived MP and the correlation between procoagulant MP and sGPV, testify to the central role of thrombin-activated platelets during MI in both DM and NDM subsets. The release of platelet and endothelial cell-derived MP persisted at D6 and was more important in DM, the associated prothrombotic risk being also reflected by higher levels of sGPV. The endothelial damage revealed by endothelial-derived MP was twice that observed in NDM patients. In DM patients presenting cardiovascular events at 6 month follow-up, MP levels were significantly higher at D1 after MI than in those without complication (24.9 ± 4.8 vs. 12.3 ± 2.7 nM PhtdSer, p = 0.02), suggesting a prognostic potential for MP.
Activated protein C generation is greatly decreased in plasma from newborns compared to adults in the presence or absence of endothelium
Authors: Patel Sanjay , Male Christoph , Berry Leslie , Mitchell Lesley , Chan Anthony 
Published: January 2004

SummaryActivated protein C (APC) generation strongly affects sepsis and thrombosis by inhibition of thrombin generation. However, it is unclear if there are age-related differences in effectiveness of protein C (PC). We studied age effects on plasma APC generation ± endothelium. Defibrinated (Ancrod) plasma (from adults or newborns (umbilical cord)) was recalcified with buffer containing tissue factor ± thrombomodulin (TM) on either plastic or endothelium (HUVEC) at 37oC. Timed subsamples of reaction mixture were taken into either heparin-EDTA or FFRCMK-EDTA solutions and analyzed for APC-PC inhibitor (APC-PCI) or APC-α1antitrypsin (APC-α1AT) by ELISAs. Since heparin converts free APC to APC-PCI, the difference in APCPCI measured in heparin-EDTA and FFRCMK-EDTA samples was equal to free active APC. APC-α2macroglobulin (APC-α2M) was measured as remaining chromogenic activity in heparin-EDTA. Free APC, APC-PCI and APC-α1AT were decreased in newborn compared to adult plasma on plastic. However, APC-α2M made up a larger fraction of inhibitor complexes in newborn plasma. On endothelium, significantly more APC, APC-PCI and APC-α1AT were generated in either plasma compared to that on plastic with excess added TM. APC, APC-PCI and APC-α1AT were also reduced and total APC-α2M increased in newborn plasma on HUVEC. Addition of PC to newborn plasma gave APC generation similar to adult plasma. Thus, free APC, APC-PCI and APC-α1AT generation is reduced in newborn compared to adult plasma with or without endothelium, likely due to reduced plasma PC levels. Endothelium enhances APC generation, regardless of plasma type, possibly because of cell surface factors such as TM, phospholipid and endothelial PC receptor.
Local INR calibration of the Owren type prothrombin assay greatly improves the intra- and interlaboratory variation
Authors: Egberg Nils , Nordin Gunnar , Stigendal Lennart , Fagerberg Inger , Lindahl Tomas , Hillarp Andreas 
Published: January 2004

SummaryIn 1999, a simplified procedure for calibration of the Owren prothrombin time (Owren PT) assay was introduced by a working group of the organisation for national quality assurance in laboratory medicine in Sweden. The new protocol allowed local calibration by means of only two lyophilised national plasma calibrators and expression of results as an international normalized ratio (INR). This is our report of a three-year follow-up involving the analysis of data from all laboratories, in hospitals (n=88 in 2002) and primary health care units (n=246 in 2002) that perform the Owren PT assay in Sweden. The interlaboratory variation was significantly improved after the introduction of the new calibration procedure. For the larger hospital-based laboratories, the mean coefficient of variation (CV) was reduced from 7.9% to 5.2% (p<0.0001) when analysing test materials with INR range 2-4. In the higher INR range (>4), the CV was reduced even further, from 10.4% to 6.8% (p<0.0001). The corresponding results from smaller laboratories in the primary health care units showed a similar decrease in CV from 8.2% to 5.7% in the INR range 2-4 (p<0.0001). At the INR range >4, the CV was reduced from 9.5% to 7.8%. The intralaboratory variation was also improved for both types of laboratory categories. This study shows an improved precision, with CV less than 6% at the therapeutic INR range, for both hospital-based laboratories and smaller laboratories in the primary health care system. The results indicate that the Owren PT assay is well suited for local INR calibration employing only two calibrant plasmas in a simplified procedure.
Beneficial effects of vitamins D and K on the elastic properties of the vessel wall in postmenopausal women: a follow-up study
Authors: Braam Lavienja , Hoeks Arnold , Brouns Fred , Hamulyák Karly , Gerichhausen Monique , Vermeer Cees 
Published: January 2004

SummaryMatrix-Gla Protein (MGP) is a strong inhibitor of vascular calcification, the expression of which is vitamin D dependent. MGP contains five γ-carboxyglutamic acid (Gla)-residues which are formed in a vitamin K-dependent carboxylation step and which are essential for its function. Hence vascular vitamin K-deficiency will result in undercarboxylated, inactive MGP which is a potential risk factor for calcification. In the present study we describe the effects of vitamin K1 and D supplementation on vascular properties in postmenopausal women. In a randomized placebo-controlled intervention study, 181 postmenopausal women were given either a placebo or a supplement containing minerals and vitamin D (MD-group), or the same supplement with vitamin K1 (MDK-group). 150 participants completed the study and analysis was performed on 108 participants. At baseline and after three years, vessel wall characteristics, including compliance coefficient (CC), distensibility coefficient (DC), intima-media thickness (IMT) and the Young’s Modulus (E) were measured to assess the effect of the supplements on the change of these parameters. The results showed that the elastic properties of the common carotid artery in the MDK-group remained unchanged over the three-year period, but decreased in the MDand placebo-group. Comparing the MDKand placebo-group, there were significant differences in decrease of DC (8.8%; p<0.05), CC (8.6%; p<0.05), and in increase of PP (6.3%; p<0.05) and E (13.2%, p<0.01).There were no significant differences between the MD-group and placebo. No significant differences were observed in the change of IMT between the three groups. It is concluded that a supplement containing vitamins K1 and D has a beneficial effect on the elastic properties of the arterial vessel wall.