Changes in serum citrullinated fibrinogen concentration associated with the phase of bacteremia patients.

Background: Citrullinated fibrinogen (C-Fbg) has been detected in rheumatoid arthritis; however, few studies have reported the role of C-Fbg in other inflammatory diseases. This study aimed to clarify the changes in serum C-Fbg associated with the bacteremia phase.

Methods: We measured serum C-Fbg concentration in bacteremia patients.

Importance of cystatin C and uric acid levels in the association of cardiometabolic risk factors in Japanese junior high school students.

Background: Serum cystatin C (CysC), a novel marker of renal function, is associated with the components of metabolic syndrome in adults. Little is known about the utility of CysC and its association with cardiometabolic risks in young subjects.

Methods And Results: In a cohort of 454 Japanese junior high school students, the distribution of serum CysC levels and associated variables were analyzed.

[A Case of Secondary Cryofibrinogenemia with Cholangiocarcinoma and Deep Venous Thrombosis].

Cryofibrinogen (CF) is a type of cryoprotein (CP) that can precipitate in cooled plasma but not in serum, and resolves upon warming. We identified a case of secondary cryofibrinogenemia with cholangiocarcinoma and deep venous thrombosis. The patient's cryocrit measured using a Wintrobe tube was 19% in sodium citrate plasma stored for 7 days at 4 degrees C.

[Polymorphism frequency of fibrinogen Bβ-chain 448Arg and Lys, and the differences of plasma fibrinogen level and clotting function with three genotypes in Japanese].

The 448th residue in the fibrinogen Bβ-chain molecule is known to be polymorphic (Arg/Lys, R/K), and its allele frequency was previously estimated to be R: 0.85 and K: 0.15 in the US.

Novel heterozygous dysfibrinogenemia, Sumida (AαC472S), showed markedly impaired lateral aggregation of protofibrils and mildly lower functional fibrinogen levels.

Introduction: We encountered a 6-year-old girl with systemic lupus erythematosus. Although no bleeding or thrombotic tendency was detected, routine coagulation screening tests revealed slightly lower plasma fibrinogen levels, as determined by functional and antigenic measurements (functional/antigenic ratio=0.857), suggesting hypodysfibrinogenemia.

Recombinant γT305A fibrinogen indicates severely impaired fibrin polymerization due to the aberrant function of hole 'A' and calcium binding sites.

Introduction: We examined a 6-month-old girl with inherited fibrinogen abnormality and no history of bleeding or thrombosis. Routine coagulation screening tests showed a markedly low level of plasma fibrinogen determined by functional measurement and also a low level by antigenic measurement (functional/antigenic ratio=0.295), suggesting hypodysfibrinogenemia.

γ375W fibrinogen-synthesizing CHO cells indicate the accumulation of variant fibrinogen within endoplasmic reticulum.

Background: Hepatic endoplasmic reticulum (ER) storage disease (HERSD) associated with hypofibrinogenemia has been reported in patients with four types of heterozygous γ-chain variant fibrinogen in the C terminal region. Of interest, substitution of γR375W induced hypofibrinogenemia and HERSD, whereas γR375G induced dysfibrinogenemia.

Objectives: To analyze the synthesis of variant fibrinogen and morphological characteristics, we established variant fibrinogen-producing cells and compared them with wild-type fibrinogen-synthesizing cells.

Nonsense-mediated mRNA decay was demonstrated in two hypofibrinogenemias caused by heterozygous nonsense mutations of FGG, Shizuoka III and Kanazawa II.

We report two novel hypofibrinogenemias, Shizuoka III and Kanazawa II, which are caused by heterozygous mutations in FGG. Shizuoka III showed c.147delT and 147_149insACA in FGG exon 3 and a subsequent frameshift mutation, resulting in mature protein γ23X (native protein: γ49X), and Kanazawa II showed c.

Successful living-related kidney transplantation in a boy with inherited dysfibrinogenemia.

In kidney transplantation, it is essential to avoid acute vascular complications, such as hemorrhage and renal vascular thrombosis, which may often lead to allograft loss. Inherited dysfibrinogenemia is a rare coagulation disorder with a wide spectrum of clinical manifestations, such as excessive bleeding and thrombosis. A 12-yr-old boy, previously diagnosed with renal hypodysplasia, was found to have reduced fibrinogen concentrations.

siRNA down-regulation of FGA mRNA in HepG2 cells demonstrated that heterozygous abnormality of the Aα-chain gene does not affect the plasma fibrinogen level.

Introduction: We encountered two afibrinogenemia patients with homozygous and compound heterozygous FGA mutation. Of interest, the patients' parents, who are heterozygous, had normal levels of plasma fibrinogen; thus, we hypothesized that liver FGA mRNA levels were higher than those of FGB and/or FGG mRNA.

Materials And Methods: To test the hypothesis, we quantitated mRNA levels of a normal liver and a human hepatocyte cell line, HepG2 cells, and performed siRNA-mediated down-regulation of the fibrinogen gene in HepG2 cells.

Fibrinopeptide A release is necessary for effective B:b interactions in polymerisation of variant fibrinogens with impaired A:a interactions.

Fibrin polymerisation is mediated by interactions between knobs 'A' and 'B' exposed by thrombin cleavage, and holes 'a' and 'b'. We demonstrated markedly delayed thrombin-catalysed fibrin polymerisation, through B:b interactions alone, of recombinant γD364H -fibrinogen with impaired hole 'a'. To determine whether recombinant variant fibrinogens with no release of fibrinopeptide A (FpA) polymerise similarly to γD364H -fibrinogen, we examined two variant fibrinogens with substitutions altering knob 'A', Aα17A- and Aα17C-fibrinogen.

[Comparison of fibrinogen synthesis and secretion between novel variant fibrinogen, nagakute (gamma305Thr --> Ala), and other variants located in gamma305-308 residues].

We found and identified a novel heterozygous dysfibrinogenemia with gammaT305A (ACA --> GCA) mutation in a 6-month old boy. Since his plasma antigenic concentration of fibrinogen was 1.12g/l and less than the lower limit of the reference interval, we guessed that the production of a variant fibrinogen might be a partial defect.

[Functional analysis for dysfibrinogenemias, Toyama and Adachi, which have a mutation of Aalpha16Arg-->His (CGT-->CAT) with aberrant fibrinopeptide A release].

We found and identified four heterozygous dysfibrinogenemias with AalphaR16H(CGT-->CAT) mutation in two families by coagulation tests and direct sequence analysis for PCR-amplified DNA fragments. Two dysfibrinogens were designated as fibrinogen Toyama and Adachi, according to the place of residence of proposituses, respectively. Patients' fibrinogen purified from plasma using immunoaffinity-chromatography was subjected to thrombin- or batroxobin-catalyzed fibrin polymerization, fibrinopeptide A (FPA) release, and clottability test.

Molecular analysis of afibrinogenemic mutations caused by a homozygous FGA1238 bp deletion, and a compound heterozygous FGA1238 bp deletion and novel FGA c.54+3A>C substitution.

We identified two afibrinogenemic girls in two Japanese families and performed molecular analysis to clarify the mechanisms of fibrinogen defects. Genetic analyses were performed by PCR amplification of the fibrinogen gene and DNA sequence analysis. To analyze the mechanisms of mature fibrinogen defects in plasma, we cloned minigenes from the proposita's PCR-amplified DNA, transfected them into CHO cells, and sequenced the cDNA amplified with the RT reaction followed by PCR.

[SNP-specific mismatched PCR for embryonic DNA detection using blood from pregnant mothers].

Background: Although prenatal diagnoses are performed using amniotic fluid cells, chorionic villus, or cord blood, these methods are hazardous for pregnant woman and the fetus. To determine a procedure for safe prenatal diagnosis, we have developed a sensitive method to analyze SNPs and we evaluated the possibility to detect fetal DNA in the maternal blood.

Methods: GeneScan analysis was performed by using mismatched specific primers for 5 SNP types and fluorescein amidite (FAM) labeled primers, and Real-time PCR analysis was also performed by using mismatched specific primers for the same SNP type and probes labeled with FAM and black hole quencher.

Heterozygous Bβ-chain C-terminal 12 amino acid elongation variant, BβX462W (Kyoto VI), showed dysfibrinogenemia.

A heterozygous patient with dysfibrinogenemia with slight bleeding and no thrombotic complications was diagnosed with fibrinogen Kyoto VI (K-VI). To elucidate the genetic mutation(s) and characterize the variant protein, we performed the following experiments and compared with identical and similar variants that have already been reported. The proposita's PCR-amplified DNA was analyzed by sequencing and her purified plasma fibrinogen underwent SDS-PAGE followed by immunoblotting, fibrin polymerization, and scanning electron microscopic observation of fibrin clot and fibers.

[Role of fibrinogen Bbeta-chain D-region 454-458 residues for assembly and secretion of intact fibrinogen].

Background: To examine the role of fibrinogen Bbeta-chain D region in the assembly and/or secretion of multichain protein, we synthesized eight variant fibrinogens with truncated Bbeta-chains in the C terminal region, terminating with 454, 455, 456 or 458 residues, and with substitution at Bbeta-455Arg by Lys, Ile, Ala or Asp in Chinese hamster ovary (CHO) cells.

Methods: A fibrinogen Bbeta-chain expression vector was altered and transfected into CHO cells that expressed normal human fibrinogen Aalpha- and gamma-chains. Expressed fibrinogens of cell lysates and culture media of the established cell lines were subjected to ELISA and immunoblot analysis.

[Assembly and secretion of mutant fibrinogens with variant gamma-chain C terminal region (gamma313-gamma345)].

Background: It has been reported that the structure of the fibrinogen gamma-chain C terminal (D) region (140-411 residues) has important functions in fibrinogen assembly and/or secretion. Variant fibrinogens, gamma313S>N, gamma336M>I, gamma341A>D, and gamma345N>D have been reported as hypofibrinogenemias or dysfibrinogenemias. To study the assembly and secretion of the variant fibrinogens containing aberrant D regions, we established CHO cells producing these four fibrinogens.

A C-terminal amino acid substitution in the gamma-chain caused by a novel heterozygous frameshift mutation (Fibrinogen Matsumoto VII) results in hypofibrinogenaemia.

We found a novel hypofibrinogenemia designated as Matsumoto VII (M-VII), which is caused by a heterozygous nucleotide deletion at position g.7651 in FGG and a subsequent frameshift mutation in codon 387 of the gamma-chain. This frameshift results in 25 amino acid substitutions, late termination of translation with elongation by 15 amino acids, and the introduction of a canonical glycosylation site.

In vitro transcription of compound heterozygous hypofibrinogenemia Matsumoto IX; first identification of FGB IVS6 deletion of 4 nucleotides and FGG IVS3-2A>G causing abnormal RNA splicing.

Background: We reported a case of hypofibrinogenemia Matsumoto IX (M IX) caused by a novel compound heterozygous mutation involving an FGB IVS6 deletion of 4 nucleotides (Delta4b) (three T, one G; between FGB IVS6-10 and -16) and FGG IVS3-2A/G, which are both identified for the first time. To examine the transcription of mRNA from the M IX gene, we cloned the wild-type and mutant genes into expression vectors.

Methods: The vectors were transfected into CHO cells and transiently produced wild-type, Bbeta- or gamma-mRNA in the cells.

Analysis of plasmin generation and clot lysis of plasma fibrinogen purified from a heterozygous dysfibrinogenemia, BbetaGly15Cys (Hamamatsu II).

We found a heterozygous dysfibrinogenemia caused by the substitution of BbetaGly15Cys and designated it fibrinogen Hamamatsu II (H-II). Although the propositus suffered an infarction of the medulla oblongata, other thrombotic risk factors, paradoxical cerebral infarction, and arterial dissection were not found. To determine whether the delayed lysis of fibrin clots or not in the context of the BbetaGly15Cys substitution, we examined the clot lysis and plasmin generation of propositus' fibrinogen.

[Functional analysis of heterozygous plasma dysfibrinogens derived from two families of gammaArg275Cys and three families of gammaArg275His, and haplotype analysis for these families].

We have identified five heterozygous dysfibrinogenemias, two families with variant fibrinogen gammaArg275Cys (CGC > TGC; Matsumoto III and Sendai) and three families with gammaArg275His (CGC > CAC; Otsu II, Iida, and Shizuoka), from PCR-amplified DNA fragments and direct sequence analysis. gammaArg275 is the most important residue in fibrinogen for the so-called "D-D interface" in protofibril elongation. We compared the functions of plasma fibrinogen purified from affected family members with gammaArg275Cys and gammaArg275His.

Recombinant variant fibrinogens substituted at residues gamma326Cys and gamma339Cys demonstrated markedly impaired secretion of assembled fibrinogen.

Background: To study the functions of residues gamma326Cys and gamma339Cys in the assembly and/or secretion of fibrinogen, recombinant fibrinogens were synthesized to replicate naturally occurring gamma326Tyr and gamma326Ser variants, along with gamma326Ala and gamma339Ala variants.

Methods: A fibrinogen gamma-chain expression vector was altered and transfected into Chinese hamster ovary (CHO) cells. Cell lysates and culture media of the established cell lines were subjected to ELISA and immunoblotting analysis.

Citrullinated fibrinogen shows defects in FPA and FPB release and fibrin polymerization catalyzed by thrombin.

Background: Antibody-antigen complexes formed by IgG autoantibodies against citrullinated proteins and citrullinated forms of the alpha- and beta-chains of fibrin in rheumatoid synovial tissue play a key role in the pathophysiology of rheumatoid arthritis.

Methods: Recombinant fibrinogen was citrullinated by rabbit skeletal muscle peptidylarginine deiminase so that we could analyze the function of citrullinated fibrinogen. Namely, thrombin-catalyzed fibrin polymerization and fibrinopeptide release, protection against plasmin digestion, and factor XIIIa-catalyzed cross-linking of fibrin or fibrinogen were performed.

[Analysis of antibody reactivity for FDP D-dimer fragments by Western blotting].

We evaluated three test kits for fibrin degradation products (FDP) D-dimer. We found that six of 217 plasma sample values obtained by Nanopia test were markedly higher than the values obtained using the other two kits. The regression equation for 211 samples (excluding six) was y=0.