It has been demonstrated that beta 2-microglobulin is a major constituent of amyloid fibrils in dialysis-related amyloidosis, a serious complication leading to bone and joint destruction in long-term hemodialysis patients. However, the molecular pathogenesis of this complication remains unknown. Several lines of evidence suggest that beta 2-microglobulin plays an active role in the development of dialysis-related amyloidosis. It is unlikely that intact beta 2-microglobulin per se contributes to the pathogenesis, because no difference in the plasma levels of intact beta 2-microglobulin has yet been found between hemodialysis patients with and without this complication. Some investigators, therefore, have focused on the modification of this molecule. Recent studies have revealed a new modification of beta 2-microglobulin in amyloid fibrils: advanced glycation end products (AGEs) formed by a nonenzymatic reaction between aldoses and proteins. Further studies have suggested that the interaction of AGE-modified beta 2-microglobulin with monocyte/macrophage and osteoclast/osteoblast gives a plausible, albeit partial, explanation for the mechanism of bone and joint destruction in dialysis-related amyloidosis. This article focuses on the modification of beta 2-microglobulin with AGEs, especially on their structure and pathological role in dialysis-related amyloidosis. Furthermore, the implication of renal failure in the pathophysiology of AGEs is also discussed.

Amyloidosis↗

PubMed1996

[Reconstruction of the crural artery in atherosclerotic occlusive arterial disease].

Limb threatening ischemia in patients with atherosclerotic occlusive disease is frequently induced by the association of crural artery occlusion. To improve the patency of distal bypass grafts, we developed a "non-dissection method" for reconstruction of these lesions. This method involves following procedures; an adventitial dissection limited to the frontal surface of the artery at the anastomotic site, complete evacuation of blood from the lower leg using a Esmarch's rubber bandage or a pneumatic tourniquet under systemic heparinization, and distal anastomosis with vein graft in end to side fashion with long arteriotomy (20 mm in length) without use of vascular clamps. This method has several advantages to the conventional method, such as easiness of suturing for accurate anastomosis, preservation of the muscular branches around the anastomosis, avoidance of surgery-induced injury to the artery and prevention of postoperative cicatrization around the anastomosis which may affect natural enlargement of the bypassed native artery. The technical details are described. Since 1982, 76 tibial bypass surgeries were performed using this method. Whenever stenotic lesions were recognized, the grafts were revised and counted as a primary occlusion. The primary patency rates at 1 year, 3 years, 5 years and 10 years are 82.2%. 75.8%, 63.9% and 63.9% respectively. The secondary patency rates are 89.1%, 84.8%, 80.8% and 80.8% respectively at the same term.

Arterial Occlusive Diseases↗

PubMed1996

Activated eosinophils stimulate phosphatidylcholine secretion in primary culture of rat type II pneumocytes.

Activated eosinophils in airway epithelium are involved in the pathogenesis of many airway diseases. We examined whether activated eosinophils influence the secretion of phosphatidylcholine (PC), the predominant component of pulmonary surfactant, in primary culture of rat type II pneumocytes. The eosinophils (10(5) cells/ml) activated by opsonized zymosan (100 micrograms/ml) increased PC secretion from the type II pneumocytes. The increased PC secretion reduced in the presence of both superoxide dismutase (2 units/ml) and catalase (1000 units/ml). These results suggest that activated eosinophils stimulate the secretion of pulmonary surfactant partly through superoxide anions.

Animals↗

PubMed1996

[A case report of surgical management of blunt ruptured right atrium with blunt ruptured liver].

This is a case report of a 23 year old female involved in a car accident that caused blunt trauma to the patient. First of all, she was found to have cardiac tamponade when the abdomen was explored to suture and to put the gaze compression on for hemostasis of the ruptured liver. Then, she was brought to our institution by the ambulance. Upon the exploration of the heart under standby of extracorporal circulation (ECC), small multiple lacerations were found at the junction of the right atrium and superior vena cava. These were sutured directly to close without ECC. On the 2nd postoperative day, she was bought to the OR again to removal of the gaze tamponade from the ruptured liver and to complete hemostasis. The patient was discarded 35 days after admission.

Accidents, Traffic↗

PubMed1996

Genetic characterization of protein C deficiency in Japanese subjects using a rapid and nonradioactive method for single-stand conformational polymorphism analysis and a model building.

We studied the molecular basis of protein C deficiency in 28 Japanese families including 4 asymptomatic families. Two showed a decreased level of function with a normal antigen concentration consistent with type II protein C deficiency and the remaining 26 showed type I deficiency with decreases in both function and antigen level. All the exons and intron/exon junctions of the protein C gene were studied using a strategy combining polymerase chain reaction (PCR) amplification and rapid nonradioactive single-strand conformational polymorphism (SSCP) analysis. The PCR-amplified fragments with aberrant migration on SSCP analysis were sequenced. We identified 11 missense mutations, 1 nonsense mutation, 2 neutral polymorphisms, 1 frameshift deletion, 1 inframe deletion, and 1 splice site mutation. We also identified two different rare mutations in the 5'-untranslated region in the protein C gene that may be responsible for the phenotype. Of these molecular defects, ten were novel. From the results of genetic analysis of 47 Japanese families with protein C deficiency reported in this and previous studies, Phe139Val and Met364Ile substitutions and a G8857 deletion were only found in Japanese subjects and seem to be a founder effect. In contrast, Arg169Trp and Val297Met substitutions, both occurring at CG dinucleotides, were commonly observed in not only Japanese but also Western populations, indicating that these are hot spots for mutation in the protein C gene. These molecular defects were found in 22 families in total, accounting for 47% of Japanese families with protein C deficiency. The structural models of the second EGF and protease domains of activated wild-type and mutant human protein C suggest a possible substrate binding exosite on two loops; one from amino acid position 349 to 357 and the other from position 385 to 388, both of which are close to each other in the three-dimensional model.

Amino Acid Sequence↗

PubMed1996

[Progress and clinical usefulness of color Doppler method in diagnosing abdominal diseases].

We report the clinical usefulness of extracorporeal color Doppler ultrasonography (CDUS), color Doppler endoscopic ultrasonography (CDEUS), and recent progress in diagnosing abdominal diseases by the color Doppler method. CDUS has the advantage of being able to be performed repeatedly and noninvasively, it is thought to be useful for the evaluation of tumor vascularity and diagnosis of vascular tumor invasion and analysis of hemodynamics in abnormal vessels found in several abdominal diseases. CDEUS, which is performed under endoscopic ultrasonography (EUS), can evaluate the hemodynamics more minutely and visualize small vessels more clearly than conventional CDUS. Recent progress in the color Doppler method, such as US color angiography and the use of contrast agents is expected to lead to a higher resolution of visualization and easier detection of abdominal vessels.

Abdomen↗

PubMed1996

[Two cases of localized organizing pneumonia simulating lung cancer].

Localized organizing pneumonia is one of the benign conditions which must be differentiated from lung cancer. We have reported two cases of localized organizing pneumonia diagnosed by histological study of surgical specimens. Two cases were initially regarded as lung cancer, because the symptoms of respiratory tract infection were not remarkable and initial roentgenographic findings revealed a tumor-like shadow. Diagnostic thoracoscopy which was less invasive upon a patient were very useful in differentiating organizing pneumonia from lung cancer.

Adult↗

PubMed1996

[Abnormalitis in the distributions of ventilation-perfusion ratios and diffusing capacity-perfusion ratios in three types of chronic obstructive pulmonary disease].

To assess whether diffusion-limited gas exchange plays a significant role in hypoxemia in various types of chronic obstructive pulmonary disease(COPD), we analyzed the distribution of ventilation-perfusion (VA/Q) ratios and of diffusing capacity-perfusion (G/Q) ratios. We compared VA/Q and G/Q distribution in patients with three basic types of COPD: emphysematous changes, bronchiolar involvement, and airway hypersecretion, which were classified based on symptoms and on findings of high-resolution CT. The results were that 1) hypoxemia was not caused by diffusion-limited gas exchange with low G/Q regions in any type of COPD, that 2) hypoxemia was not caused by inhomogeneities in VA/Q distribution, that 3) emphysematous changes and bronchiolar involvement were associated with high and low VA/Q regions, respectively, and that 4) either hypersecretion itself or related airway abnormalities may cause low VA/Q regions to form.

Aged↗

PubMed1996

Completion arteriography in paramalleolar bypasses: effect of configurational changes, with special reference to spasm, on long-term outcome.

PURPOSE: The purpose of this study was to ascertain the durability of paramalleolar bypasses and elucidate the effect of configurational changes, especially spasm, seen on the completion arteriography upon the outcome. DESIGN: Retrospective study. SETTING: University hospital experience. PATIENTS AND METHODS: Nineteen paramalleolar bypass operations in sixteen patients performed between April 1988 and March 1995 were studied retrospectively. Reversed saphenous vein grafts were used in all cases. One patient required an additional microvascular free flap transfer to cover a foot amputation stump. Seventeen completion arteriograms were obtained. Patients were followed for an average of 37 months. RESULTS: One patient died in hospital, giving a hospital death rate of 5.9%. Two grafts failed immediately and could not be salvaged. Inadvertent perforation of one graft required partial replacement with a polytetrafluoroethylene graft; it eventually failed after 42 months. There were no other graft failures during follow-up. Nine completion arteriograms showed spastic change of the run-off artery, but this change had disappeared on repeat angiograms obtained before discharge. CONCLUSION: Spasm of run-off artery is a frequent finding in distal bypass surgery and adversely affects the immediate outcome. Heparinization during the first 24 hours after surgery may reduce the consequences of spasm, and long-term patency can be expected providing that the whole graft consists of autogenous vein.

Adult↗

PubMed1995

Identification and characterization of a novel protein kinase, TESK1, specifically expressed in testicular germ cells.

We have isolated cDNA clones encoding the rat and human forms of a novel protein kinase, termed TESK1 (testis-specific protein kinase 1). Sequence analysis indicates that rat TESK1 contains 628 amino acid residues, composed of an N-terminal protein kinase consensus sequence followed by a C-terminal proline-rich region. Human TESK1 contains 626 amino acids, sharing 92% amino acid identity with its rat counterpart. The protein kinase domain of TESK1 is structurally similar to those of LIMK (LIM motif-containing protein kinase)-1 and LIMK2, with 49-50% sequence identity. Phylogenetic analysis of the protein kinase domains revealed that TESK1 is most closely related to a LIMK subfamily. Chromosomal localization of human TESK1 gene was assigned to 9p13. Anti-TESK1 antibody raised against the C-terminal peptide of TESK1 recognized two polypeptides of 68 and 80 kDa in cell lysates of COS cells transfected with human TESK1 cDNA expression plasmid. TESK1 protein expressed in COS cells exhibited serine/threonine kinase activity, when myelin basic protein was used as a substrate. Northern blot analysis revealed that TESK1 mRNA was specifically expressed in rat and mouse testicular germ cells. The TESK1 mRNA in the testis was detectable only after the 18th day of postnatal development of mice and was mainly expressed in the round spermatids. These observations suggest that TESK1 has a specific function in spermatogenesis.

Alternative Splicing↗

PubMed1995

Functional consequences of the Ser334-->Pro mutation in a human factor X variant (factor XMarseille).

A factor X molecular variant was identified in a 55-year-old woman at a routine preoperative coagulation screening. Plasma factor X antigen was normal, whereas factor X activity was decreased when factor X was activated by either the extrinsic pathway (21%), the intrinsic pathway (21%) or the factor X activator from Russell viper venom, RVV-X (26%). Factor XMarseille was isolated from plasma by immunoaffinity chromatography and compared with normal factor X purified by the same method. Activation of factor XMarseille by factor IXa or by RVV-X in a purified system showed that the rate of cleavage was decreased, whereas once produced, factor XaMarseille had a normal catalytic efficiency for either the peptide substrate S-2765 (D-Arg-Gly-Arg-NH-Np) or prothrombin. The rate of inhibition of factor XaMarseille by antithrombin III was also normal. Defective proteolysis of factor XMarseille by factor IXa or by RVV-X was the consequence of a threefold decrease in the kcat for the activation of factor XMarseille while the Km of RVV-X or factor IXa for factor X was normal. We have determined the molecular basis of the defect in the factor XMarseille gene by amplification of all eight exons, single-strand conformational polymorphism analysis of the amplified exons and subsequent sequence analysis. The patient was homozygous for a T-->C mutation in exon VIII, resulting in the substitution of Ser334 by proline. From comparison of three-dimensional models of various serine proteases, it appears that Ser334 is located within a surface-exposed variable region of factor X. This observation suggests that the Ser334-->Pro mutation either is responsible for a misalignment of the active sites of specific factor X activators in close proximity to the cleavage site, or that the Ser-->Pro mutation alters the spatial orientation of the cleavage site by nonlocal modifications of factor X structure.

Animals↗

PubMed1995

Identification of two highly homologous presynaptic proteins distinctly localized at the dendritic and somatic synapses.

Through screening of a murine brain cDNA library, we have isolated two brain specific cDNAs encoding highly homologous proteins, named 921-L and 921-S, comprised of 134 amino acids with 80% identity. Immunohistological study with the mAbs raised against the bacterially expressed 921 proteins showed that 921-L protein is distributed at the dendritic region and 921-S at the neuronal somatic surface. Immuno-electron microscopic study revealed that both 921 proteins are localized at the presynaptic terminal, indicating that the 921 proteins are differentially expressed at the dendritic and somatic presynapses.

Adaptor Proteins, Vesicular Transport↗

PubMed1995

A giant nucleopore protein that binds Ran/TC4.

Ran/TC4 is a small nuclear G protein that forms a complex with the chromatin-bound guanine nucleotide release factor RCC1 (ref. 2). Loss of RCC1 causes defects in cell cycle progression, RNA export and nuclear protein import. Some of these can be suppressed by overexpression of Ran/TC4 (ref. 1), suggesting that Ran/TC4 functions downstream of RCC1. We have searched for proteins that bind Ran/TC4 by using a two-hybrid screen, and here we report the identification of RanBP2, a novel protein of 3,224 residues. This giant protein comprises an amino-terminal 700-residue leucine-rich region, four RanBP1-homologous (refs 9, 10) domains, eight zinc-finger motifs similar to those of NUP153 (refs 11, 12), and a carboxy terminus with high homology to cyclophilin. The molecule contains the XFXFG pentapeptide motif characteristic of nuclear pore complex (NPC) proteins, and immunolocalization suggests that RanBP2 is a constituent of the NPC. The fact that NLS-mediated nuclear import can be inhibited by an antibody directed against RanBP2 supports a functional role in protein import through the NPC.

Amino Acid Sequence↗

PubMed1995

Effect of heparin on the inhibition of factor Xa by tissue factor pathway inhibitor: a segment, Gly212-Phe243, of the third Kunitz domain is a heparin-binding site.

Tissue factor pathway inhibitor (TFPI) inhibits the tissue factor--factor VIIa complex and factor Xa with its first and second Kunitz domains (K1 and K2), respectively. The inhibitory activity is enhanced by heparin, and the C-terminal basic part has been shown to be a heparin-binding site (HBS-1). To characterize and localize a second heparin-binding site (HBS-2), we studied the effect of heparin on the inhibitory activity of two forms of recombinant human TFPI, the full-length TFPI (rTFPI), and TFPI lacking the C-terminal basic part (rTFPI-C), by assaying the inhibition of human factor Xa. rTFPI-C inhibited factor Xa with an initial Ki of 6.79 nM in the absence of Ca2+ and 22.3 nM in the presence of 5 mM CaCl2. Heparin decreased the initial Ki to 1.79 nM in the absence of Ca2+ and 2.68 nM in the presence of 5 mM CaCl2, indicating the presence of HBS-2 in rTFPI-C. The dissociation constant for the binding of HBS-2 with heparin was determined to be 830 nM using fluorescein-labeled heparin and rTFPI-C. Heparin enhanced the inhibitory activity of a fragment consisting of the K2 and K3 domains, but it did not stimulate the inhibitory activity of the K2 domain. A synthetic peptide mimicking from Gly212 to Phe243 in the K3 domain reduced the effect of heparin on the inhibition by rTFPI-C and rTFPI. These results defined the location of HBS-2 in the basic region of the K3 domain between Gly212 and Phe243.

Amino Acid Sequence↗