Identification and characterization of the genome of a papillomavirus from skin lesions of four-toed hedgehogs (Atelerix albiventris)

The present study describes the clinical and pathological characteristics of skin lesions in two four-toed hedgehogs (Atelerix albiventris). We performed inverse PCR to identify the genome of papillomavirus (PV) in the skin lesions and subsequently sequenced the full genome of the virus, which was tentatively named Atelerix albiventris papillomavirus 1 (AalbPV1). The overall sequences of the viral genomes of both four-toed hedgehogs were identical. This study first identified the presence of a novel PV in Japanese four-toed hedgehogs and provided genetic information about this virus.

Morphological study of apocrine gland tumors in domestic Richardson's ground squirrels (Urocitellus richardsonii)

The morphology of 58 apocrine tumors from 31 domestic Richardson's ground squirrels (Urocitellus richardsonii) was examined, comparing tumor subtypes with clinical information and histological findings. The squirrels included 23 males (74%) and 8 females (26%). Of the 58 tumors, 36 (62%) were located from the cervical skin to the dorsal skin, 17 (29%) were from the perioral region to the cheek, and the location was unrecorded for the remaining 5 squirrels (9%). Histologically, 49 tumors (84%) were apocrine adenocarcinomas, 6 were apocrine adenomas (10%), and 3 were apocrine cysts (5%). The 49 apocrine adenocarcinomas were subclassified as 16 (33%) cystic papillary type, 16 (33%) tubulopapillary type, 12 (24%) solid type, and 5 (10%) micropapillary invasive type. Fisher's exact test revealed correlations between tumor subtypes and tumor diameters, nuclear atypia, tumor margins, vascular invasion, and periodic acid-Schiff (PAS) positivity. This study showed a predominance of apocrine adenocarcinomas with various histological subtypes. In addition, subclassification of these tumors was useful for predicting the biological behavior of apocrine gland tumors in Richardson's ground squirrels.

Cutaneous papilloma and multicentric squamous cell carcinoma in four-toed hedgehogs (Atelerix albiventris)

Skin lesions possibly caused by Papillomavirus infections in two four-toed hedgehogs are described. In case 1, there was a papillary mass on the right hind limb. Histologically, the mass was consistent with a viral papilloma. In the other case, multifocal papillary masses with erosions and ulcers were found throughout the body, mainly on the extremities. Histology showed continuative lesions composed of acanthosis, Bowenoid in situ carcinoma, and squamous cell carcinoma, with abrupt transitions between the lesions. In both cases, keratinocytes in the granular layer infrequently had features of koilocytes and intranuclear inclusion bodies, and immunohistochemical staining was positive for anti-human papillomavirus antibody. To the best of the authors’ knowledge, this is the first pathological documentation of possibly papillomavirus-associated skin lesions in four-toed hedgehogs.

Thymoma originating from the cervical component of the thymus in a degu

A 5-y-old, male degu (Octodon degus) was presented with a subcutaneous mass in the ventral aspect of the cervical area. The mass was removed surgically. Histologically, the mass was a densely cellular, expansile neoplasm, with compression of thymic tissue to the periphery. The neoplasm consisted of solid sheets of polygonal cells, mixed with fewer small lymphocytes. Rare Hassall bodies were scattered throughout the mass. Polygonal cells were positive for anti-keratin/cytokeratin AE1/AE3 antibody, and small lymphocytes were positive for anti-CD3 antibody. The histopathologic and immunohistochemical findings were consistent with a thymoma. In addition, an autopsy revealed myxosarcoma of the right thoracic wall with metastasis to the lung. To our knowledge, thymoma originating from the cervical component of the thymus has not been documented previously in a rodent species.

Impact of higher detection rate of residual pulmonary thromboemboli one-year after acute pulmonary embolism: modified CT scan imaging method with modified CT obstruction index

Background

Recently, post pulmonary embolism (PE) syndrome or chronic thromboembolic disease after acute PE, has been recognized as important long-term complications. Furthermore, patients may develop with chronic thromboembolic pulmonary hypertension.

Purpose

We aimed to evaluate the frequency of residual pulmonary thromboemboli after acute PE by using our “higher”-resolution CT scan imaging method to detect residual thromboemboli down to sub-segmental pulmonary arteries.

Methods

This study was a prospective multi-center observational study. We enrolled consecutive 34 patients with acute symptomatic PE whose informed consent was obtained, and followed up for one year. One year after the onset of acute PE, patients were referred to our hospital and multiple examination including CT scan, 6-minute walk test (6MWT), questionnaire of SF-36, echocardiography and laboratory testing were performed. Additionally, we have modified the CT obstruction index (CTOI) to quantitatively evaluate the thromboemboli down to sub-segmental pulmonary arteries.

Results

Mean age was 60.5±15.8 years, and 56% were male. No patient was categorized as low recurrent VTE risk which was caused by transient factors, one patient was associated with active cancer, and 12% had known thrombophilia. In 85% of the patients, this onset was the first obvious episode of PE. At diagnosis, elevated B-type natriuretic peptide (BNP) (≥100 pg/ml) or N-terminal (NT)-proBNP (≥500 pg/ml) was observed in 45% of the patients. Median tricuspid regurgitation peak gradient (TRPG) by echocardiography was 30.9 (19.3–50.1) mmHg. Among all, 35% of the patients received single-drug approach with DOACs. At discharge, all of the patients except two were treated with DOACs.

One year after the onset, 21% of the patient were in NYHA II and others were in NYHA I. It was notable that pulmonary thromboemboli was detected by our CT scan in 76% of the patients. Modified CTOI was median 11.9 (1.8–24.4) % as shown in the figure.

In multiple regression analysis, TRPG at diagnosis and BNP at one month were significantly associated with mCTOI (β=0.536, p=0.002 and β=−0.482, p=0.003, respectively). Additionally, lowest SpO2 during 6MWT after one year from the onset, tended to inversely associate with mCTOI (β=−0.341, p=0.052).

Conclusions

Using our modified CT scan imaging method and modified CTOI, residual pulmonary thromboemboli was able to be detected more frequently than the previous studies. Residual pulmonary thromboemboli could be one of the cause of the post PE syndrome and lead to exercise-induced desaturation.

Figures

Funding Acknowledgement

Type of funding source: None

Primary localized histiocytic sarcoma of the lumbar vertebrae in a four-toed hedgehog (Atelerix albiventris)

We describe a case of primary localized histiocytic sarcoma of the lumbar vertebrae in a four-toed hedgehog. The case showed aggressive osteolysis of lumbar vertebrae on radiography, and a soft-tissue mass effacing this region was noted, suggesting a neoplastic lesion. No metastatic lesions were apparent. Antemortem diagnosis was challenging, and necropsy was performed. Histopathological and immunohistochemical findings were consistent with localized histiocytic sarcoma. This report provides documentation of the clinical and pathologic features of an unusual form of histiocytic sarcoma localizing to lumbar vertebrae in a four-toed hedgehog.

Activation of a chondrocyte volume-sensitive Cl(-) conductance prior to macroscopic cartilage lesion formation in the rabbit knee anterior cruciate ligament transection osteoarthritis model

OBJECTIVE

The anterior cruciate ligament transection (ACLT) rabbit osteoarthritis (OA) model confers permanent knee instability and induces joint degeneration. The degeneration process is complex, but includes chondrocyte apoptosis and OA-like loss of cartilage integrity. Previously, we reported that activation of a volume-sensitive Cl(-) current (ICl,vol) can mediate cell shrinkage and apoptosis in rabbit articular chondrocytes. Our objective was therefore to investigate whether ICl,vol was activated in the early stages of the rabbit ACLT OA model.

DESIGN

Adult Rabbits underwent unilateral ACLT and contralateral arthrotomy (sham) surgery. Rabbits were euthanized at 2 or 4 weeks. Samples were analyzed histologically and with assays of cell volume, apoptosis and electrophysiological characterization of ICl,vol.

RESULTS

At 2 and 4 weeks post ACLT cartilage appeared histologically normal, nevertheless cell swelling and caspase 3/7 activity were both significantly increased compared to sham controls. In cell-volume experiments, exposure of chondrocytes to hypotonic solution led to a greater increase in cell size in ACLT compared to controls. Caspase-3/7 activity, an indicator of apoptosis, was elevated in both ACLT 2wk and 4wk. Whole-cell currents were recorded with patch clamp of chondrocytes in iso-osmotic and hypo-osmotic external solutions under conditions where Na(+), K(+) and Ca(2+) currents were minimized. ACLT treatment resulted in a large increase in hypotonic-activated chloride conductance.

CONCLUSION

Changes in chondrocyte ion channels take place prior to the onset of apparent cartilage loss in the ACLT rabbit model of OA. Further studies are needed to investigate if pharmacological inhibition of ICl,vol decreases progression of OA in animal models.

Wild boars from Sweden, Austria, the Czech Republic and Japan possess intact mannose-binding lectin 2 (MBL2) genes

The two-nucleotide deletion recently detected in the mannose-binding lectin 2 gene in purebred and crossbred domestic pigs was not found among 68 wild boars representing 4 populations from Europe and Asia. This suggests that the deletion is a result of breeding and/or genetic drift/bottle necks.

MBL1 genotypes in wild boar populations from Sweden, Austria, the Czech Republic, and Japan

The single nucleotide polymorphism (SNP) G949T in the mannose-binding lectin ( MBL ) 1 gene has been associated with low MBL-A concentration in serum and detected at different frequencies in various European pig populations. However, the origin of this SNP is not known. Part of the MBL1 gene was sequenced in 12 wild boar/Large White crossbred pigs from the second backcross (BC 2 ) generation in a family material originating from two wild boar x Large White intercrosses. Also, MBL-A serum concentration was measured in the entire BC 2 generation (n = 45). Furthermore, the genotypes of 68 wild boars from Sweden, Austria, the Czech Republic, and Japan were determined in regard to five previously described SNPs in MBL1 . The T allele of G949T was present among the BC 2 animals. MBL-A serum concentration in the BC 2 animals showed a bimodal distribution, with one-third of the animals at levels between 0.7 and 1.6 μg mL(-1) and the remaining pigs at levels around 13 μg mL(-1) . There was a co-variation between the presence of the T allele and low MBL-A concentration in serum. The genotyping of the wild boars revealed differences between populations. The T allele of G949T was not detected in the Austrian and Japanese samples and is thus unlikely to be an original feature of wild boars. In contrast, it was present at high frequency (0.35) among the Swedish wild boars, probably representing a founder effect. Five MBL1 haplotypes were resolved. Only two of these were present among the Japanese wild boars compared to four in each of the European populations. This difference may reflect differences in selection pressure and population history.

Worldwide genetic relationships of pigs as inferred from X chromosome SNPs

The phylogeography of the porcine X chromosome has not been studied despite the unique characteristics of this chromosome. Here, we genotyped 59 single nucleotide polymorphisms (SNPs) in 312 pigs from around the world, representing 39 domestic breeds and wild boars in 30 countries. Overall, widespread commercial breeds showed the highest heterozygosity values, followed by African and American populations. Structuring, as inferred from FST and analysis of molecular variance, was consistently larger in the non-pseudoautosomal (NPAR) than in the pseudoautosomal regions (PAR). Our results show that genetic relationships between populations can vary widely between the NPAR and the PAR, underscoring the fact that their genetic trajectories can be quite different. NPAR showed an increased commercial-like genetic component relative to the PAR, probably because human selection processes to obtain individuals with high productive parameters were mediated by introgressing boars rather than sows.

Identification of N-homocysteinylated apolipoprotein AI in normal human serum

Background

In human serum, a portion of homocysteine (Hcy) exists as an N-linked form to the ε-amino group of protein lysine residues. N-homocysteinylated proteins differ structurally and functionally from native proteins. The present study strives to develop detection and potential semi-quantification methods for N-homocysteinylated apolipoprotein AI ( N-Hcy-apoAI) in human serum.

Methods

Serum treated with or without cysteamine was supplied to isoelectric focusing (IEF) followed by an immunoblot using an anti-apoAI antibody. Cysteamine treatment increased the isoelectric point for N-Hcy-apoAI, but not for unmodified apoAI, due to the presence of -SH group(s) derived from Hcy and the absence of a cysteine residue in the apoAI molecule. N-Hcy-apoAI was semi-quantified from the scanned immunoblot pattern via a computer.

Results

After cysteamine treatment, N-Hcy-apoAI in the serum was identified by IEF at the position with a higher pI value compared with intact apoAI. The reproducibility (between assays) of the semi-quantification method was 19.1% CV (coefficient of variation) for an average ratio 5.9% of N-Hcy-apoAI to the whole apoAI in the serum. Approximately 1.0–7.4% of apoAI was N-homocysteinylated in the serum obtained from 27 healthy subjects. Neither the ratio of N-Hcy-apoAI nor its concentration, calculated by total apoAI concentration, indicated correlation with the so-called total (free and S-linked) Hcy concentration.

Conclusions

We directly found that a portion of apoAI in the serum undergoes homocysteinylation in an N-linkage manner, and used this to develop a potential semi-quantification method for N-Hcy-apoAI.

Evolution of a pairing-induced pseudogap from the superconducting gap of (Bi,Pb)2Sr2CuO6

We have performed an ultrahigh-resolution angle-resolved photoemission spectroscopy study of slightly overdoped (Bi,Pb)2Sr2CuO6 to elucidate the origin of the pseudogap. By using a newly developed xenon-plasma light source, we determined the comprehensive momentum and temperature dependencies of the superconducting gap and the pseudogap. We found that the antinodal pseudogap persists far above the superconducting transition temperature and is smoothly connected to the nodal gap. The characteristic temperature of the pseudogap scales well with the superconducting gap size irrespective of the momentum location. The present experimental results point to the pairing origin of the pseudogap.

Primary chylopericardium with pulmonary lymphedema

Primary chylopericardium is an uncommon entity, and its association with pulmonary lymphedema has been rarely reported.We describe a case of primary chylopericardium with pulmonary lymphedema developing into hypoxemia. The pulmonary lesions were histologically diagnosed as pulmonary lymphangiectasis and lymphedema on lung biopsies. Lymphedema seems to suggest the existence of chylous reflux with pulmonary lymphangiectasis. The patient underwent pericardial fenestration and resection of the thoracic duct. After the operation, the chylous accumulation in the pericardial cavity had disappeared,and hypoxemia improved following the disappearance of the pulmonary lesions.

A novel exogenous concentration-gradient collagen scaffold augments full-thickness articular cartilage repair

OBJECTIVES

A collagen scaffold has been long used in order to enhance the regeneration of articular cartilage. In the present study, we investigate the effectiveness of a concentration-gradient (CG) collagen that is designed to recruit efficiently the mesenchymal stem cells (MSCs) to the central region of the full-thickness cartilage defects via haptotaxis.

METHODS

The present study used Cellmatrix (0.3% type I collagen; Nitta gelatin, Osaka, Japan) as the collagen material. We prepared 33%CG collagen gel and 50%CG collagen gel. No gradient collagen gel served as negative control. Full-thickness cartilage defects were created at the patella groove of the rabbit knee, to which the three different collagen gels were transplanted. Bromodeoxyuridine (BrdU) positive, proliferating cells were enumerated and localized, whereas the histological grading score for cartilage regeneration was counted. The expression of type I and type II collagens was evaluated by immunohistochemistry. We also confirmed that the MSCs migrate toward the collagen substrate of higher concentration in a stringently in vitro haptotactic manner.

RESULTS

Enumeration of the BrdU-positive cells demonstrated that 33%CG collagen gel recruited a significantly larger number of proliferating cells to the central region of the cartilage defect. The histological grading score for the regenerated cartilage treated with 33%CG collagen gel was superior to the other groups.

CONCLUSIONS

CG collagen scaffold recruits effectively the MSCs to the center of full-thickness cartilage defect and enhances regeneration of the full-thickness cartilage defect.

B:b interactions are essential for polymerization of variant fibrinogens with impaired holes 'a'

BACKGROUND

Fibrin polymerization is mediated by interactions between knobs 'A' and 'B' exposed by thrombin cleavage, and holes 'a' and 'b' always present in fibrinogen. The role of A:a interactions is well established, but the roles of knob:hole interactions A:b, B:b or B:a remain ambiguous.

OBJECTIVES

To determine whether A:b or B:b interactions have a role in thrombin-catalyzed polymerization, we examined a series of fibrinogen variants with substitutions altering holes 'a': gamma364Ala, gamma364His or gamma364Val.

METHODS

We examined thrombin- and reptilase-catalyzed fibrinopeptide release by high-performance liquid chromatography, fibrin clot formation by turbidity, fibrin clot structure by scanning electron microscopy (SEM) and factor (F) XIIIa-catalyzed crosslinking by sodium dodecylsulfate polyacrylamide gel electrophoresis.

RESULTS

Thrombin-catalyzed fibrinopeptide A release was normal, but fibrinopeptide B release was delayed for all variants. The variant fibrinogens all showed markedly impaired thrombin-catalyzed polymerization; polymerization of gamma364Val and gamma364His were more delayed than gamma364Ala. There was absolutely no polymerization of any variant with reptilase, which exposed only knobs 'A'. SEM showed that the variant clots formed after 24 h had uniform, ordered fibers that were thicker than normal. Polymerization of the variant fibrinogens was inhibited dose-dependently by the addition of either Gly-Pro-Arg-Pro (GPRP) or Gly-His-Arg-Pro (GHRP), peptides that specifically block holes 'a' and 'b', respectively. FXIIIa-catalyzed crosslinking between gamma-chains was markedly delayed for all the variants.

CONCLUSION

These results demonstrate that B:b interactions are critical for polymerization of variant fibrinogens with impaired holes 'a'. Based on these data, we propose a model wherein B:b interactions participate in protofibril formation.

Co-localization of TFF2 with gland mucous cell mucin in gastric mucous cells and in extracellular mucous gel adherent to normal and damaged gastric mucosa

Trefoil factor 2 (TFF2) is mucin associated peptide that has a mucosal barrier function in addition to participating in repair and healing. We examined the localization of TFF2 and gastric mucins in gastric mucous cells, the surface mucous gel layer (SMGL) adherent to normal gastric mucosa, and in the mucoid cap covering gastric erosions. Carnoy's solution, or formalin/picric acid-fixed paraffin embedded materials from resected stomachs and formalin-fixed paraffin embedded gastric biopsy materials were used. Sections were immunostained for the TFF2 and histochemically stained for gastric mucins. In addition, thick sectioned gastric mucosa fixed in Carnoy's solution were stained with FITC-labeled GSA-II lectin specific for gland mucous cell mucin and examined for three-dimensional images of the SMGL using a confocal laser scanning microscope. The TFF2 and gland mucous cell mucin were found intermixed together in the gastric gland mucous cells, in the SMGL in laminated layers, and in the mucoid cap. A laminated arrangement of continuous sheets of gland mucous cell mucin in the SMGL was demonstrated in the three-dimensional images. Co-localization of the TFF2 with gland mucous cell mucin suggests a physical interaction between the TFF2 and gland mucous cell mucin. The TFF2 trapped in the adherent mucins may be responsible for mucosal defense, healing, and repair.

Functional analysis of recombinant Bbeta15C and Bbeta15A fibrinogens demonstrates that Bbeta15G residue plays important roles in FPB release and in lateral aggregation of protofibrils

BACKGROUND AND OBJECTIVES

Analysis of dysfibrinogens has improved our understanding of molecular defects and their effects on the function of intact fibrinogen. To eliminate the influence of plasma heterozygous molecules, we synthesized and analyzed recombinant-variant fibrinogens.

METHODS

We synthesized two recombinant-variant fibrinogens with a single amino acid substitution at the 15Gly residue in the Bbeta-chain: namely, Bbeta15Cys and Bbeta15Ala.

RESULTS

Western blotting analysis of purified fibrinogen revealed the existence of a small amount of a dimeric form only for Bbeta15Cys fibrinogen. For Bbeta15Cys fibrinogen, functional analysis indicated (a) no thrombin-catalyzed fibrinopeptide B (FPB) release and (b) markedly impaired lateral aggregation in thrombin- and reptilase-catalyzed fibrin polymerizations. For Bbeta15Ala fibrinogen, such analysis indicated slight impairments of both thrombin-catalyzed FPB release and lateral aggregation in thrombin-catalyzed fibrin polymerization, but nearly normal lateral aggregation in reptilase-catalyzed fibrin polymerization. These impaired lateral aggregations were accompanied by thinner fibrin fiber diameters (determined by scanning electron microscopy of the corresponding fibrin clots).

CONCLUSION

We conclude that a region adjacent to Bbeta15Gly plays important roles in lateral aggregation not only in desA fibrin polymerization, but also in desAB fibrin polymerization, and we speculate that the marked functional differences between Bbeta15A and Bbeta15C fibrinogens in FPB release and fibrin polymerization might not only be due to the presence of a substituted cysteine residue in Bbeta15C fibrinogen, but also to the existence of disulfide-bonded forms. Finally, our data indicate that the Bbeta15Gly residue plays important roles in FPB release and lateral aggregation of protofibrils.

Comparison of thrombin-catalyzed fibrin polymerization and factor XIIIa-catalyzed cross-linking of fibrin among three recombinant variant fibrinogens, gamma 275C, gamma 275H, and gamma 275A

BACKGROUND AND OBJECTIVES

We have previously reported that recombinant gamma 275Cys fibrinogen exhibits a marked impairment of functions as well as aberrant fibrin clot and bundle structures, as compared with wild-type, gamma 275Arg, and plasma fibrinogen from a heterozygous proband. Since gamma Arg275His mutations have also been reported in 10 families, we synthesized recombinant gamma 275His fibrinogen and gamma 275Ala fibrinogen (as a control) and analyzed and compared them with gamma 275Cys and gamma 275Arg.

METHODS

A variant gamma-chain expression plasmid was transfected into Chinese hamster ovary cells expressing normal human fibrinogen A alpha- and B beta-chains. After purification of the recombinant variant fibrinogens, we performed functional analyzes for thrombin-catalyzed fibrin polymerization and factor XIIIa (FXIIIa)-catalyzed gamma-gamma dimer formation from fibrin or fibrinogen and also ultrastructural analysis of fibrin clots and bundles.

RESULTS

By comparison with both gamma 275His and gamma 275Ala fibrinogens, recombinant gamma 275Cys fibrinogen exhibited a more impaired gamma-gamma dimer formation from fibrin or fibrinogen, a more aberrant fibrin clot structure, and thicker fibers in fibrin bundles. In 1 : 1 mixtures of gamma 275Arg and gamma 275Cys fibrinogens or gamma 275Arg and gamma 275His fibrinogens, thrombin-catalyzed fibrin polymerization and both fibrin clot and fiber structures showed some compensation (as compared with gamma 275Cys or gamma 275His alone).

CONCLUSION

These results strongly suggest that an amino acid substitution of gamma 275Arg alone disrupts D:D interactions in thrombin-catalyzed fibrin polymerization and the formation of fibrin bundles and fibrin clots. Moreover, the existence of a subsequent disulfide-linked Cys in gamma 275C fibrinogen augments the impairment caused by a His or Ala substitution.

Recombinant fibrinogen, gamma275Arg-->Cys, exhibits formation of disulfide bond with cysteine and severely impaired D:D interactions

BACKGROUND AND OBJECTIVES

Analysis of dysfibrinogens has provided useful information aiding our understanding of molecular defects in fibrin polymerization. We have already reported impaired fibrin polymerization in a variant fibrinogen (gammaArg275Cys), the Cys being located in the D:D interface. Since this substitution occurred in a heterozygous individual, interpretation of the functional analysis was complicated. We tried to resolve this complication by synthesizing a recombinant variant fibrinogen.

METHODS

A variant gamma-chain expression plasmid was transfected into Chinese hamster ovary cells expressing normal human fibrinogen Aalpha- and Bbeta-chains. The recombinant variant fibrinogen (gamma275C) was purified using an immunoaffinity column, and we compared its structure and functions with those of normal recombinant fibrinogen (gamma275R) and plasma variant fibrinogen.

RESULTS

Mass analyses showed the existence of disulfide-linked Cys in both patient and recombinant variant fibrinogens. Functional analyses indicated that both fibrin polymerization and gamma-gamma dimer formation were markedly impaired in the variant fibrinogen. The impairments were much more pronounced in gamma275C than in plasma variant fibrinogen. In addition, scanning electron microscopic observation of fibrin clots made from gamma275C revealed less dense fibrin fiber bundles and larger fiber diameter than in those made from gamma275R, and also the existence of many aberrant fibrin fibers with tapered ends.

CONCLUSIONS

These results indicate that gammaArg275 has an important residue affecting the structure and function of the gamma-chain C-terminal domain. However, the variant D:D interface can interact with that of the normal fibrinogen existing in a heterozygous patient with dysfibrinogenemia.

Fibrinogens Kosai and Ogasa: Bbeta15Gly-->Cys (GGT-->TGT) substitution associated with impairment of fibrinopeptide B release and lateral aggregation

We found two heterozygous dysfibrinogenemias, designated fibrinogen Kosai and fibrinogen Ogasa. Kosai was associated with arteriosclerosis obliterans but Ogasa showed no bleeding or thrombotic tendencies. The plasma fibrinogen concentrations from the two propositi (Ogasa and Kosai) were much lower when determined by the thrombin-time method (0.94 and 1.06 g L(-1), respectively) than when determined by the immunological method (2.87 and 2.72 g L(-1), respectively). We performed DNA sequencing and functional analyses to clarify the relationship between the structural and functional abnormalities. Genetic analysis of PCR-amplified DNA from the propositi identified the heterozygous substitution Bbeta15Gly-->Cys (GGT-->TGT). Western blotting analysis of purified fibrinogen revealed the existence of albumin-fibrinogen complexes. Functional analyses indicated that compared with the normal control, the propositi's fibrinogen released only half the normal amount of fibrinopeptide B and showed markedly impaired polymerization. In addition, the observation of thinner fibers in fibrin clots (by scanning electron microscopy) indicated markedly defective lateral aggregation in the variant fibrinogens. The impaired functions may be due to the substitution of Cys for Bbetao15Gly plus the existence of some additional disulfide-bonded forms.

Interaction of the SH2 domain of Fyn with a cytoskeletal protein, beta-adducin

Fyn is a Src family tyrosine kinase expressed abundantly in neurons and believed to have specific functions in the brain. To understand the function of Fyn tyrosine kinase, we attempted to identify Fyn Src homology 2 (SH2) domain-binding proteins from a Nonidet P-40-insoluble fraction of the mouse brain. beta-Adducin, an actin filament-associated cytoskeletal protein, was isolated by two-dimensional gel electrophoresis and identified by tandem mass spectrometry. beta-Adducin was tyrosine phosphorylated by coexpression with wild type but not with a kinase-negative form of Fyn in COS-7 cells. Cell staining analysis showed that coexpression of beta-adducin with Fyn induced translocation of beta-adducin from the cytoplasm to the periphery of the cells where it was colocalized with actin filaments and Fyn. These findings suggest that tyrosine-phosphorylated beta-adducin associates with the SH2 domain of Fyn and colocalizes under plasma membranes.