Molecular diagnosis of Myxobolus spirosulcatus associated with encephalomyelitis of cultured yellowtail, Seriola quinqueradiata Temminck & Schlegel

Mass mortality of cultured yellowtail, Seriola quinqueradiata, has recently been reported from fish farms in western Japan. Previous studies revealed that diseased fish were characterized by encephalomyelitis and presporogonic stages of a myxosporean-like parasite in the spinal cord. However, the parasite has remained unidentified because of the lack of mature stages being present. Thus, in the present study, analysis of the small subunit ribosomal DNA (18S rDNA) of the parasite as well as in situ hybridization (ISH) studies using histological sections of the infected tissue was conducted. The 18S rDNA of the myxosporean had higher sequence similarities with those of bile-duct-infecting myxosporeans rather than those infecting nervous tissues and was identified as Myxobolus spirosulcatus. The ISH using specific probes demonstrated that the DNA amplified was derived from the multinuclear organisms found in histological sections. A highly sensitive and specific PCR-based assay for M. spirosulcatus was developed, which revealed a high prevalence of infection in cultured yellowtail that exhibited the clinical signs of encephalomyelitis.

BMP signalling permits population expansion by preventing premature myogenic differentiation in muscle satellite cells

Satellite cells are the resident stem cells of adult skeletal muscle, supplying myonuclei for homoeostasis, hypertrophy and repair. In this study, we have examined the role of bone morphogenetic protein (BMP) signalling in regulating satellite cell function. Activated satellite cells expressed BMP receptor type 1A (BMPR-1A/Alk-3) and contained phosphorylated Smad proteins, indicating that BMP signalling is operating during proliferation. Indeed, exogenous BMP4 stimulated satellite cell division and inhibited myogenic differentiation. Conversely, interfering with the interactions between BMPs and their receptors by the addition of either the BMP antagonist Noggin or soluble BMPR-1A fragments, induced precocious differentiation. Similarly, blockade of BMP signalling by siRNA-mediated knockdown of BMPR-1A, disruption of the intracellular pathway by either Smad5 or Smad4 knockdown or inhibition of Smad1/5/8 phosphorylation with Dorsomorphin, also caused premature myogenic differentiation. BMP signalling acted to inhibit the upregulation of genes associated with differentiation, in part, through regulating Id1. As satellite cells differentiated, Noggin levels increased to antagonise BMP signalling, since Noggin knockdown enhanced proliferation and impeded myoblast fusion into large multinucleated myotubes. Finally, interference of normal BMP signalling after muscle damage in vivo perturbed the regenerative process, and resulted in smaller regenerated myofibres. In conclusion, BMP signalling operates during routine satellite cell function to help coordinate the balance between proliferation and differentiation, before Noggin is activated to antagonise BMPs and facilitate terminal differentiation.

Mild resistance to thyroid hormone with a truncated thyroid hormone receptor beta

Recent studies have revealed mutations in the thyroid hormone receptor beta (TR beta) gene as a cause of the most cases of the thyroid hormone resistance syndrome. We have identified a novel nonsense mutation in codon 449 in the 3' end of exon 10 in the TR beta gene in a 16-year-old male patient with generalized resistance to thyroid hormone who also had familial thyroxine binding globulin deficiency. Receptor protein generated from this gene is thought to be 13 amino acid deficient at carboxy-terminus. Resistance to thyroid hormone was mild at least when the patient was evaluated. The patient was eumetabolic in the presence of elevated plasma-free thyroid hormone levels, and both thyrotrope and peripheral tissues responded to triiodothyronine (T3) administration. This mildness of resistance is in contrast to severe resistance to thyroid hormone in two previously reported cases with truncated receptors in which 16 amino acids or 11 amino acids were deficient at C-terminus. Thus, truncation of C-terminus of thyroid hormone receptor beta does not uniformly produce sever resistance.

Uncommon electrocardiographic changes corresponding to symptoms during recurrent pulmonary embolism as documented by computed tomography scans

Electrocardiographic (ECG) findings of pulmonary embolism (PE) include S1Q3T3 pattern, right bundle-branch block, right-axis deviation, and T-wave inversion in medial precordial leads. We report other uncommon ECG changes associated with various symptoms during recurrent PE as documented by computed tomography (CT) scans in a single patients. An 83-year-old woman was admitted with PE secondary to deep venous thrombosis in the left leg. During episodes of chest pain, ECG showed QTc prolongation (480 ms) with new T-wave inversion in leads III, aVF, and V1-V3, and ST-segment depression in leads V5-V6. Despite adequate anticoagulant therapy, recurrent episodes of PE occurred in the hospital. When the patient experienced sudden chest tightness, ECG showed a new S-wave notch in lead V1 and clock-wise rotation with sinus tachycardia. She also experienced transient syncope with hypotension. At this time, ECG showed transient atrioventricular junctional rhythm followed by sinus arrest, and CT scan showed a new massive embolus in the main pulmonary trunk with right ventricular dilatation, as demonstrated by echocardiography. The mechanism responsible for QTc prolongation with ST-T changes, the S-wave notch in lead V1 with clockwise rotation, or atrioventricular junctional rhythm with sinus arrest during PE may be associated with myocardial ischemia, acute right ventricular overload, or vagal reflex, respectively.

Exercise-induced QTc-interval changes for predicting improvement in regional blood flow in ischemic myocardium and cardiac output after coronary angioplasty in patients with right bundle-branch block

BACKGROUND

We have previously shown that QT-interval changes are more useful than ST-T changes in evaluating the severity of exercise-induced myocardial ischemia in patients with right bundle-branch block (RBBB).

HYPOTHESIS

The purpose of this study was to evaluate whether the improvement in regional myocardial blood flow (RMBF) in ischemic areas and cardiac output after percutaneous transluminal coronary angioplasty (PTCA) can be predicted by exercise-induced QT-interval changes prior to PTCA.

METHODS

The RMBF and cardiac output were quantified with nitrogen-13 ammonia positron emission tomography at rest and during exercise in 20 patients with RBBB and ischemic heart disease before and 6 months after PTCA, and in 9 healthy volunteers.

RESULTS

Before PTCA, exercise-induced prolongation by < 20 ms or shortening of the Bazett-corrected QT (QTc) interval (454 +/- 38 to 451 +/- 41 ms, p = NS) was observed in 13 patients (Group 1) and prolongation by > or = 20 ms (429 +/- 44 to 466 +/- 50 ms, p < 0.002) was observed in 7 (Group 2). The number of regions of exercise-induced ischemia was significantly greater in Group 2 than in Group 1 (4.0 +/- 1.2 vs. 2.1 +/- 1.2, p < 0.01). The RMBF in regions of exercise-induced ischemia and cardiac output at rest was not significantly different between Groups 1 and 2, whereas during exercise both the parameters were significantly lower in Group 2 than in Group 1 (both p < 0.05). After successful PTCA, RMBF both at rest and during exercise improved significantly in Group 1 (0.67 +/- 0.04 to 0.71 +/- 0.06 ml/min/g, 0.74 +/- 0.05 to 0.84 +/- 0.08 ml/min/g; both p < 0.0001), but did not improve significantly in Group 2 (0.63 +/- 0.05 to 0.65 +/- 0.07 ml/min/g, 0.65 +/- 0.04 to 0.69 +/- 0.11 ml/ min/g; both p = NS). Cardiac output during exercise improved significantly in Group 1 (6.4 +/- 0.7 to 7.4 +/- 0.9 l/min; p < 0.002) but not in Group 2 (5.7 +/- 0.6 to 5.9 +/- 0.6 l/min; p = NS).

CONCLUSIONS

Our results suggest that the marked prolongation of the QTc interval induced by pre-PTCA exercise may predict a lack of improvement in RMBF in ischemic areas and cardiac output after PTCA in patients with RBBB and ischemic heart disease.

Application of devices for safe laparoscopic hepatectomy

The continuing evolution of a variety of laparoscopic instrument and device has been gradually applied to the laparoscopic hepatectomy in many countries. Recent experience has persuaded us that there are great potential benefits derived from laparoscopic hepatectomy and much has been learned about patient selection, the grade of surgical difficulty with respect to tumor location, and the required instrumentation. Among these efforts, various ways of hepatic parenchymal transection with mechanical devices have been attempted and continuing to innovate to perform safe laparoscopic hepatectomy Important technologic developments and improved endoscopic procedures are being established equipment modifications. For safe laparoscopic hepatectomy, it is important to have all necessary equipment. The intraoperative laparoscopic ultrasonography, microwave coagulators, ultrasonic dissection, argon beam coagulators, laparoscopic coagulation shears, endolinear staplers and TissueLink monopolar sealer are essential. This procedure is in need that well experienced endoscopic surgeon and well-experienced liver surgeon should be collaborated in laparoscopic hepatectomy and the indications are strictly followed based upon the location and size of tumors. Finally critical determinant for success and safe laparoscopic hepatectomy is through familiarity with the relevant laparoscopic instruments and equipments. Laparoscopic hepatectomy is expected to develop further in the future as a new surgical instrument, equipment and method, which improves patients' quality of life.

Involvement of elevated expression of multiple cell-cycle regulator, DTL/RAMP (denticleless/RA-regulated nuclear matrix associated protein), in the growth of breast cancer cells

To investigate the detailed molecular mechanism of mammary carcinogenesis and discover novel therapeutic targets, we previously analysed gene expression profiles of breast cancers. We here report characterization of a significant role of DTL/RAMP (denticleless/RA-regulated nuclear matrix associated protein) in mammary carcinogenesis. Semiquantitative RT-PCR and northern blot analyses confirmed upregulation of DTL/RAMP in the majority of breast cancer cases and all of breast cancer cell lines examined. Immunocytochemical and western blot analyses using anti-DTL/RAMP polyclonal antibody revealed cell-cycle-dependent localization of endogenous DTL/RAMP protein in breast cancer cells; nuclear localization was observed in cells at interphase and the protein was concentrated at the contractile ring in cytokinesis process. The expression level of DTL/RAMP protein became highest at G(1)/S phases, whereas its phosphorylation level was enhanced during mitotic phase. Treatment of breast cancer cells, T47D and HBC4, with small-interfering RNAs against DTL/RAMP effectively suppressed its expression and caused accumulation of G(2)/M cells, resulting in growth inhibition of cancer cells. We further demonstrate the in vitro phosphorylation of DTL/RAMP through an interaction with the mitotic kinase, Aurora kinase-B (AURKB). Interestingly, depletion of AURKB expression with siRNA in breast cancer cells reduced the phosphorylation of DTL/RAMP and decreased the stability of DTL/RAMP protein. These findings imply important roles of DTL/RAMP in growth of breast cancer cells and suggest that DTL/RAMP might be a promising molecular target for treatment of breast cancer.

Bone regeneration by synthetic octacalcium phosphate and its role in biological mineralization

Octacalcium phosphate (Ca8H2(PO4)6 * 5H2O; OCP) has been advocated to be a precursor of biological apatite crystals in bone and tooth. Recent studies, using physical techniques, showed that OCP is present as a transient phase during biological apatite formation in human dentin, porcine enamel and murine bone. However, there is still a controversy regarding the chemical nature of the first mineral formed in the biominerals. A number of studies have demonstrated that synthetic OCP shows bone regenerative and biodegradable characteristics, rather than other calcium phosphate bone substitute materials, such as hydroxyapatite (Ca10(PO4)6(OH)2; HA) ceramic. It seems likely that synthetic OCP may be an alternative to autogenous bone graft. It is known that OCP contains alternative layers of water molecules and an apatite structure, and that the transition of OCP to HA is likely to be spontaneous and irreversible. The conversion process induces modification of local environment adjacent to OCP surface, including the changes in adsorption of serum proteins and concentration of calcium and inorganic phosphate ions. This article reviews the possible application to bone regeneration by synthetic OCP and the mechanism to enhance bone regeneration in relation to biological mineralization in bone and tooth.

Elevation of matrix metalloproteinases and interleukin-6 in the culprit coronary artery of myocardial infarction

BACKGROUND

Interleukin-6 (IL-6) and metalloproteinases (MMPs) are involved in the instability of vulnerable plaque associated with the induction of acute myocardial infarction (AMI). We examined the regional changes of cytokines, MMPs and adhesion molecules in patients with AMI to elucidate how these factors are involved in the onset of AMI.

MATERIALS AND METHODS

One hundred and twenty-two patients with AMI were included. Blood was aspirated from the culprit coronary artery with a thrombectomy catheter, and was also sampled from peripheral veins during the coronary intervention. Control samples were obtained from the peripheral blood of age-matched patients.

RESULTS

The serum levels of IL-6 (P < 0.05), tumour necrosis factor-alpha (P < 0.005), MMP-1 (P < 0.001), MMP-13 (P < 0.001), soluble intercellular adhesion molecule-1 (P < 0.005), and soluble vascular cellular adhesion molecule-1 (P < 0.05) in peripheral blood were significantly higher in the AMI group than in the controls. Aspirated serum contained significantly higher levels of IL-6 (P < 0.001), MMP-1 (P < 0.001), and MMP-13 (P < 0.05) compared to the peripheral blood of AMI. Serum IL-6 levels were significantly higher in the aspirated than in the peripheral blood in the patients hospitalized within 6 h and 6-12 h, but were similar in the aspirated and peripheral blood of the patients hospitalized 12-24 h after the onset of AMI. There were no differences between the aspirated serum and peripheral blood in the levels of interleukin-1beta and MMP-2.

CONCLUSIONS

The levels of MMP-1, MMP-13 and IL-6 were higher in the culprit coronary artery than in the peripheral blood. These factors appear to be involved in the early stage of AMI.

CDC20, a potential cancer therapeutic target, is negatively regulated by p53

The p53 protein inhibits malignant transformation through direct and indirect regulation of transcription of many genes related to cell cycle, apoptosis and cellular senescence. A number of genes induced by p53 have been well characterized, but biological significance of genes whose expression was suppressed by p53 is still largely undisclosed. To clarify the roles of p53-suppressive genes in carcinogenesis, we analysed two data sets of whole-genome expression profiles, one for cells in which wild-type p53 was exogenously introduced and the other for a large number of clinical cancer tissues. Here, we identified CDC20 that was frequently upregulated in many types of malignancies and remarkably suppressed by ectopic introduction of p53. CDC20 expression was suppressed by genotoxic stresses in p53- and p21-dependent manners through CDE-CHR elements in the CDC20 promoter. Furthermore, small interference RNA (siRNA)-mediated silencing of p53 induced CDC20 expression in normal human dermal fibroblast cells. As we expected, treatment of cancer cells with siRNA against CDC20 induced G(2)/M arrest and suppressed cell growth. Our results indicate that p53 inhibits tumor cell growth through the indirect regulation of CDC20 and that CDC20 might be a good potential therapeutic target for a broad spectrum of human cancer.

Binding of Bacillus thuringiensis Cry1A toxins to brush border membrane vesicles of midgut from Cry1Ac susceptible and resistant Plutella xylostella

Plutella xylostella strain resistant (PXR) to Bacillus thuringiensis Cry1Ac toxin was not killed at even more than 1000 microg Cry1Ac/g diet but killed by Cry1Ab at 0.5 microg/g diet. In contrast, susceptible strain (PXS) was killed by Cry1Ac at 1 microg/g diet. Cy3-labeld Cry1A(s) binding to brush border membrane vesicles (BBMV) prepared from both strains were analyzed with direct binding assay. The Kd value of Cry1Aa to both BBMV was almost identical: 213.2 and 205.8 nM, and 263.5 and 265.0 nM for Cry1Ac. The highest Kd values were in Cry1Ab which showed most effective insecticidal activity in PXS and PXR, 2126 and 2463 nM, respectively. These results clearly showed that the BBMV from PXR and PXS could equally bind to Cry1Ac. The binding between BBMV and Cy3-labeled Cry1Ac was inhibited only by anti-175 kDa cadherin-like protein (CadLP) and -252 kDa protein antisera, but not by anti-120 kDa aminopeptidase. This supports that resistance in PXR resulted from the abortion of pore formation after the binding of Cry1Ac to the BBMV. And furthermore, the importance of 175K CadLP and P252 proteins in those bindings was suggested. We briefly discuss possible mechanisms of the resistance.

Molecular typing by pulsed-field gel electrophoresis of Flavobacterium psychrophilum isolates derived from Japanese fish

Sixty-four isolates of Flavobacterium psychrophilum from ayu, Plecoglossus altivelis altivelis (Temminck & Schlegel), and other fish (n=16) in Japan and the type strain (NCIMB 1947(T)) were typed using pulsed-field gel electrophoresis (PFGE) with endonuclease BlnI and XhoI. These isolates were classified into 20 clusters and 42 genotypes by PFGE analysis. The most predominant cluster of isolates from ayu was cluster XII (n=20), followed by clusters XVII, XVI, XX, XI, IX, X, XIII and XV; the remaining 17 isolates from other fish were divided into clusters I, II, III, IV, V, VI, VII, VIII, XIV, XVIII and XIX. The PFGE genotype of isolates from ayu clearly differed from those of other fish. The isolates from ayu in Gunma Prefecture belonged to clusters XII, XVI, XVII and XX, and the strains of three of these clusters (XII, XVII and XX) were isolated from ayu in 15 of 19 prefectures. PFGE typing enabled more accurate classification of isolates into clusters than previously achieved by analysing the restriction fragment length polymorphism of PCR products. These results suggest that F. psychrophilum isolated from ayu and other fish are genetically different and strains with several PFGE types have spread within Japan.

Involvement of upregulation of DEPDC1 (DEP domain containing 1) in bladder carcinogenesis

In an attempt to disclose mechanisms of bladder carcinogenesis and discover novel target molecules for development of treatment, we applied a cDNA microarray to screen genes that were significantly transactivated in bladder cancer cells. Among the upregulated genes, we here focused on a novel gene, (DEPDC1) DEP domain containing 1, whose overexpression was confirmed by northern blot and immunohistochemical analyses. Immunocytochemical staining analysis detected strong staining of endogenous DEPDC1 protein in the nucleus of bladder cancer cells. Since DEPDC1 expression was hardly detectable in any of 24 normal human tissues we examined except the testis, we considered this gene-product to be a novel cancer/testis antigen. Suppression of DEPDC1 expression with small-interfering RNA significantly inhibited growth of bladder cancer cells. Taken together, these findings suggest that DEPDC1 might play an essential role in the growth of bladder cancer cells, and would be a promising molecular-target for novel therapeutic drugs or cancer peptide-vaccine to bladder cancers.

Bacterial translocation in small intestinal ischemia-reperfusion injury and efficacy of Anti-CINC antibody treatment

The involvement of bacterial translocation in small intestinal ischemia-reperfusion injuries and the efficacy of using anti-CINC antibodies for treatment were investigated. A model for ischemia-reperfusion injury of the small intestine was constructed by clamping the supramesenteric artery (for 90 min) in rats. Anti-CINC antibodies and saline were given just before the induction of ischemia in the treatment group and the control group, respectively. Six hours after reperfusion, bacteria were detected in the mesenteric lymph nodes, but the 'bacteria-positive' rate was significantly lower in the treatment group than in the control group. Bacterial cultures and endotoxins in the blood were negative in both groups up to 24 h later. The plasma cytokine levels showed similar variations, although the increases were significantly lower after reperfusion in the treatment group. In addition, the degrees of neutrophil infiltration and mucosal injury were attenuated in the small intestine, and the structure of the liver was maintained. Furthermore, the 1-week survival was improved. These results suggest that bacterial translocation occurred predominantly via the lymphatic system and that anti-CINC antibody treatment exerted a protective effect against small intestinal ischemia-reperfusion injury.