Correlation Between Vascular Endothelial Growth Factor C Expression and Lymph Node Metastasis in T1 Carcinoma of the Colon and Rectum

Purpose. Vascular endothelial growth factor C (VEGF-C) is known to be associated with the development of the lymphatic vessel system. Recently, VEGF-C is thought to be correlated with lymph node metastasis in some malignant tumors. In this study, we investigated the correlation between VEGF-C expression and lymph node metastasis in early carcinoma of the colon and rectum. Methods. Two hundred and twenty-one endoscopically biopsied specimens from patients with T1 colorectal carcinoma prior to operation were investigated by an immunohistochemical study. Results. VEGF-C expression was more frequently observed in the tumors with nodal metastasis than in those without metastasis. Moreover, a multivariate analysis indicated that VEGF-C expression is an independent predictor of lymph node metastasis. Conclusion. VEGF-C staining using endoscopically biopsied specimens prior to operation could be of use in the prediction of lymph node metastasis and in preoperative selection of treatment in patients with T1 colorectal carcinoma.     

Laparoscopic resection of ileal lipoma diagnosed by multidetector-row computed tomography

Intussusception is rare in adults and it is difficult to diagnose on admission. We present the case of a 43-year-old woman with the chief complaint of nausea and upper abdominal pain. Abdominal multidetector-row computed tomography showed ileo-ileal small bowel intussusception with an intraluminal soft tissue mass with attenuation numbers suggestive of a lipoma. The patient was treated with a laparoscopic-assisted extracorporeal partial resection of the small bowel including ileal lipoma, followed by a functional end-to-end anastomosis. Histologic diagnosis of the resected tumor, 2.4×2.0×2.0 cm, was an intestinal lipoma. This case serves as the basis of a review of small bowel intussusception in adults secondary to lipomas. It focuses on the utility of multidetector-row computed tomography and the cosmetic, physical, and economic benefits of laparoscopic surgery as well as the rarity of the disease.     

Alpha1-adrenoceptor-mediated breakdown of phosphatidylinositol 4,5-bisphosphate inhibits pinacidil-activated ATP-sensitive K+ currents in rat ventricular myocytes

Phosphatidylinositol 4,5-bisphosphate (PIP2) stimulates ATP-sensitive K+ (K(ATP)) channel activity. Because phospholipase C (PLC) hydrolyzes membrane-bound PIP2, which in turn may potentially decrease K(ATP) channel activity, we investigated the effects of the alpha1-adrenoceptor-G(q)-PLC signal transduction axis on pinacidil-activated K(ATP) channel activity in adult rat and neonatal mouse ventricular myocytes. The alpha1-adrenoceptor agonist methoxamine (MTX) reversibly inhibited the pinacidil-activated K(ATP) current in a concentration-dependent manner (IC50 20.9+/-6.6 micromol/L). This inhibition did not occur when the specific alpha1-adrenoceptor antagonist, prazosin, was present. An involvement of G proteins is suggested by the ability of GDPbetaS to prevent this response. Blockade of PLC by U-73122 (2 micromol/L) or neomycin (2 mmol/L) attenuated the MTX-induced inhibition of K(ATP) channel activity. In contrast, the MTX response was unaffected by protein kinase C inhibition or stimulation by H-7 (100 micro mol/L) or phorbol 12,13-didecanoate. The MTX-induced inhibition became irreversible in the presence of wortmannin (20 micro mol/L), an inhibitor of phosphatidylinositol-4 kinase, which is expected to prevent membrane PIP2 replenishment. In excised inside-out patch membranes, pinacidil induced a significantly rightward shift of ATP sensitivity of the channel. This phenomenon was reversed by pretreatment of myocytes with MTX. Direct visualization of PIP2 subcellular distribution using a PLCdelta pleckstrin homology domain-green fluorescent protein fusion constructs revealed reversible translocation of green fluorescent protein fluorescence from the membrane to the cytosol after alpha1-adrenoceptor stimulation. Our data demonstrate that alpha1-adrenoceptor stimulation reduces the membrane PIP2 level, which in turn inhibits pinacidil-activated K(ATP) channels.     

Zinc Increases ABCA1 by Attenuating Its Clearance Through the Modulation of Calmodulin Activity

Aim: We previously revealed that Ca⁺⁺-activated calmodulin binds to ABCA1 by the region near the PEST sequence and retards its calpain-mediated degradation to increase HDL biogenesis. Calmodulin activity is reportedly modulated also by other nutritional divalent cations; thus, we attempted to determine whether Zn⁺⁺ is involved in the regulation of ABCA1 stability through the modulation of calmodulin activity.Methods: The effects of Zn⁺⁺ on ABCA1 expression was investigated in J774 mouse macrophage cell-line cells and HepG2 human hepatoma cell-line cells.Results: Zn⁺⁺ increased ABCA1 expression, not by increasing the mRNA but by attenuating its decay rate, more prominently in the presence of cAMP. Accordingly, it enhanced cell cholesterol release with extracellular apolipo-protein A-I. Calmodulin binding to ABCA1 was increased by Zn⁺⁺ and Ca⁺⁺. Zn⁺⁺ suppressed calpain-mediated hydrolysis of the peptide of ABCA1 cytosolic loop, including the PEST sequence and the calmodulin-binding site, in a calmodulin-dependent fashion, in the presence of the minimum amount of Ca⁺⁺ to activate calpain, but not calmodulin. Calpain activity was not directly inhibited by Zn⁺⁺ at the concentration for enhancing calmodulin binding to ABCA1.Conclusion: Nutritional divalent cation Zn⁺⁺ is involved in the regulation of ABCA1 activity and biogenesis of HDL through the modulation of calmodulin activity. The results were consistent with previous clinical findings that Zn⁺⁺ increased plasma HDL in the conditions of sympathetic activation, such as type 2 diabetes and chronic hemodialysis.     

Recombinant cell-detecting RaDR-GFP in mice reveals an association between genomic instability and radiation-induced-thymic lymphoma

In this study, we aimed to investigate how homologous recombinant (HR)-related genomic instability is involved in ionizing radiation (IR)-induced thymic lymphoma in mice. We divided five-week-old Rosa26 Direct Repeat-GFP (RaDR-GFP) transgenic mice into non-IR control and IR groups and exposed the mice in the IR group to a 7.2 Gy dose of γ-rays, delivered in 1.8 Gy fractions, once a week for four weeks. We then estimated mouse survival and recorded their body, thymus, and spleen weights. The frequency of HR events in the chromosomes of the thymus, bone marrow, and spleen cells and the phenotype of thymic lymphoma cells were analyzed using fluorescence-activated cell sorting (FACS). We found that most mice in the IR group developed thymic lymphoma, their survival rate decreasing to 20% after 180 days of IR exposure, whereas no mice died in the non-IR control group until day 400. The thymus and spleen weighed significantly more in the IR-4-month group than that in the non-IR group; however, we observed no significant differences between the body weights of the control and IR mice. FACS analysis indicated that the frequency of HR events significantly increased at two and four months after the last IR dose in the bone marrow and thymus cells, but not in the spleen cells of RaDR-GFP transgenic mice, suggesting that recombinant cells accumulated in the thymus upon IR exposure. This suggests that IR induces genome instability, revealed as increased HR, that drives the development of thymic lymphoma. Additionally, phenotypic analysis of lymphoma cells showed an increase in the CD4^-/CD8⁺ (CD8SP) cell population and a decrease in the CD4⁺/CD8^- (CD4SP) cell population in the IR-4-month group compared to that in the non-IR group, indicating that IR induces an aberrant cell phenotype characteristic of lymphoma. In conclusion, we observed a significant increase in HR events and abnormal phenotype in thymic lymphoma cells at two and four months after IR exposure in both the thymus and bone marrow tissues, suggesting that genomic instability is involved in the early stages of thymic lymphomagenesis. Our study indicates that HR-visualizing RaDR-GFP transgenic mice can help explore the links between the molecular mechanisms of genome instability and IR-induced tumorigenesis.     

Cytological features of carcinoma of the collecting ducts of Bellini in voided urine cytology

Carcinoma of the collecting ducts of Bellini (CCDB) is a rare histological type of renal cell carcinoma. This article describes the cytological features of CCDB in voided urine, confirmed on the basis of the histopathology and immunohistochemistry. The CCDB cells occurred singly in loose aggregates and in small clusters, occasionally in a rosette‐like structure. There were various types of cancer cells, including round to oval, spindle, and tadpole‐like cells. The nuclei usually showed coarse chromatin, inconspicuous nucleoli, and lacy to vacuolated cytoplasm. CCDB of the kidney is a rare cytodiagnostic challenge in voided urine cytology alone. When the cytological diagnosis is considered, it is necessary to perform immunocytochemistry and correlate the clinical history and imaging studies. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Processive movement of single 22S dynein molecules occurs only at low ATP concentrations

We have analyzed the movement of single 22S dynein molecules from Tetrahymena cilia by using a nanometer measuring system equipped with optical tweezers. Statistical analysis proved that a single molecule of 22S dynein can move processively and develop force at low concentrations of ATP (<20 microM). The maximum force was approximately 4.7 pN, and the force-velocity curve was convex down. During force development, dynein molecules showed stepwise displacement of approximately 8 nm and frequently exhibited backward steps of approximately 8 nm. At higher concentrations of ATP (>/=20 microM) single molecules of 22S dynein were not observed to move processively. Twenty-two S dynein seems to switch over from a processive mode to a nonprocessive mode, sensing a subtle change of ATP concentrations. These observations indicate that the processivity, maximum force, and step size of dynein are similar to those of kinesin, but the ATP concentration-dependence, force-velocity relationship, and backward steps are clearly distinct from kinesin.     

The treatment of unruptured tubal pregnancy with intratubal methotrexate injection under laparoscopic control

Nine patients with unruptured tubal pregnancies of 6-9 weeks' duration were treated with methotrexate intratubal injection under laparoscopic control. Urinary hCG levels decreased immediately after completion of the procedure, with a median time of 11 days (range 1-29) to resolution. Tubal patency on the side of the ectopic gestation was confirmed by hysterosalpingography 1-3 months after the procedure in all cases. This method requires a reduced methotrexate dosage compared with intramural or intravenous therapy. The indications are unruptured tubal pregnancy of 4 cm or less in diameter and urinary hCG levels of 8000 mIU/mL or lower.     

Prevention of halothane-induced hepatotoxicity by hemin pretreatment: protective role of heme oxygenase-1 induction

Reductive metabolism of halothane in phenobarbital-pretreated rats is known to increase free radical formation that results in hepatotoxicity. It also is associated with a marked induction of microsomal heme oxygenase-1 (HO-1), suggesting that there is an alteration in heme metabolism. In this study, we examined heme metabolism in rats pretreated with phenobarbital, followed by exposure to halothane-hypoxia. In this model, there was a significant decrease in microsomal cytochrome P450 content in the liver, followed by a rapid increase in free heme concentration and a decrease in the level of mRNA for the nonspecific delta-aminolevulinate synthase. A transient but dramatic induction of HO-1 mRNA and a prolonged induction of heat shock protein 70 mRNA also occurred. The HO-1 protein was detected principally in the hepatocytes around the central vein. Serum alanine transaminase (ALT) activity, an indicator of hepatic dysfunction, increased continuously throughout the experiment. Hemin pretreatment induced hepatic HO-1 with abrogation of the halothane-induced hepatotoxicity in this model, as judged by ALT activity and normal histology. Our findings in this study thus indicate that halothane-induced hepatotoxicity is due not only to its reductive metabolite formation, but also to an increase in hepatic free heme concentration, which is a potent prooxidant; HO-1 induction is an important protective response against such changes. This is also the first study to demonstrate that hemin pretreatment, which induces HO-1 prior to exposure to halothane, effectively prevents halothane-induced hepatotoxicity.