The stimulatory effect of beta-endorphin on the plasma prolactin levels was diminished in the rats treated with 6-hydroxydopamine

Intraventicular injection of beta-endorphin (beta LPH_61^?91) in urethane anesthetized male rats led to a dose dependent increase of plasma prolactin levels. Intravenous injection of apomorphine completely abolished the stimulatory effect of beta-endorphin. Animals treated with 6-hydroxydopamine (6-OHDA) and 6-OHDA plus desmethylimipramine showed inhibition of beta-endorphin induced prolactin release. These results suggest that beta-endorphin presynaptically inhibits the activity of dopaminergic neurones, leading to the stimulation of plasma prolactin levels.     

Intravesical treatment of bladder cancer with recombinant human interferon-β

Summary In order to examine its clinical efficacy, recombinant human interferon- (rIFN-) was instilled intravesically into 51 patients with superficial bladder cancer. Ten patients, who received intermittent intravesical instillation at a dose of (3–36) × 10⁶ U rIFN- on days 1–3 every week, showed no response. Thirty-two patients received intravesical instillation at a dose of (3–36) × 10⁶ U every day for 10–20 days. Eight patients showed partial response, indicating an efficacy rate of 25%. Nine patients received divided doses of 18 × 10⁶ U twice a day every day for 10–20 days. Six patients showed partial response, indicating an efficacy rate of 67%. This value was significantly higher than that obtained by administering divided doses. The response to intravesical instillation therapy with rIFN- varies with treatment protocol. Frequent and longer exposure to rIFN- may induce better regression of superficial bladder cancer. Six incidences of side-effects were found in five cases (9.8%): pollakiuria in one, pain on micturition in two, fever in two, and eruption in one case. All of these side-effects were slight and reversible after drug withdrawal. Laboratory tests showed only a few changes with low severity. Thus, rIFN- is potentially a new drug for instillation therapy of superficial bladder cancer, in view of the absence of adverse effects.     

Akt is an endogenous inhibitor toward tumor necrosis factor-related apoptosis inducing ligand-mediated apoptosis in rheumatoid synovial cells

Akt is known to be activated in the rheumatoid synovial tissues. We examined here functional role of Akt during tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-mediated apoptosis in rheumatoid synovial cells. Rheumatoid synovial cells in vitro were rapidly committed to apoptosis in response to TRAIL in mitochondria-dependent manner whereas Akt and extracellular signal-regulated kinase (ERK) were also phosphorylated. TRAIL-mediated apoptosis in synovial cells was significantly increased through inactivation of Akt by LY294002, however, that process was not so changed by adding ERK inhibitor, PD98059. Platelet-derived growth factor (PDGF) clearly phosphorylated both Akt and ERK in synovial cells, and PDGF pretreatment markedly suppressed TRAIL-mediated synovial cell apoptosis. The use of not PD98059 but LY294002 abrogated PDGF-mediated inhibitory effect toward TRAIL-induced apoptosis in synovial cells. The above protective effect of Akt was confirmed by the use of short interfering RNA (siRNA)-directed inhibition of Akt. Our data suggest that Akt is an endogenous inhibitor during TRAIL-mediated synovial cell apoptotic pathway, which may explain that synovial cells in situ of the rheumatoid synovial tissues are resistant toward apoptotic cell death in spite of death receptor expression.     

Specific expression of annexin III in rat-small-hepatocytes

Small hepatocytes are cells that express characteristic phenotypes such as a high growth potential and differentiation capacity. In order to identify rat-small-hepatocyte specific proteins, we separated the cellular proteins of isolated small and parenchymal hepatocytes by 2D polyacrylamide gel electrophoresis. Comparison of their profiles revealed a protein with a molecular mass of 37 kDa in the small hepatocytes that was not present in the parenchymal hepatocytes. Proteolytic peptide mass fingerprinting was used to identify the protein and it was found to be annexin III. The validity of the identification was confirmed by Western blot analysis with anti-annexin III antibody.     

粒重差异显著的两种水稻颖果发育比较

为了探讨控制水稻(Oryza sativa L.)颖果发育的因素,选择了颖果干重有显著差异的Ootikara (大粒,36mg/粒)和Habataki (小粒,18 mg/粒)两个水稻品种,比较颖果重量、胚乳细胞数、果皮和胚乳的结构以及某些生理活性等变化。结果指出:与Habataki相比, Ootikara子房壁细胞和颖果的持续生长期长,最终颖果的胚乳细胞数目和每个细胞的平均干重大; Ootikara颖果的脱氢酶和H2O2酶活性、穗的呼吸速率、剑叶的绿色程度和光合速率等维持高水平的时间长;Ootikara子房背部维管束失去功能的时间也较迟。结果表明,大粒品种的库容大和生理活性期长是其颖果能显著增大的生理原因。     

Connexin 32 down-regulates the fibrinolytic factors in metastatic renal cell carcinoma cells

Fibrinolytic factors have an important role in tumor progression through the degradation of extracellular matrix. The increased levels of urokinase-type plasminogen activator (uPA), uPA-receptor (uPAR) and type-1 PA inhibitor (PAI-1) are reported in human renal cell carcinoma (RCC). Connexin (Cx) gene, a member of gap junction, is known to act as a tumor suppressor gene. We have reported that Cx32 improves malignant phenotypes of metastatic RCC cells via the inhibition of Src-dependent signaling. In this study, we examined the effect of expression of Cx32 gene on the production of uPA, uPAR and PAI-1, and on the induction of PAI-1 stimulated by hypoxia in a human metastatic RCC cell line, Caki-1 cells. Cx32 expression decreased both mRNA level and production of PAI-1, uPA and uPAR in Caki-1 cells. Cx32 also decreased hypoxia-inducible factor (HIF)-1alpha and HIF-2alpha mRNA level. PP1, a Src inhibitor, significantly decreased PAI-1, uPA, uPAR and HIF-alpha mRNA levels in Caki-1 cells. Furthermore, Cx32 suppressed the induction of HIF-2alpha protein in Caki-1 cells under hypoxia. PAI-1 mRNA level in Cx32-transfected Caki-1 cells was lower than that of mock transfectant under hypoxic conditions. These results suggest that Cx32 might reduce PAI-1, uPA and uPAR production in metastatic RCC cells via the inhibition of Src-dependent induction of HIF-1alpha and HIF-2alpha gene expression and that Cx32 might suppress hypoxia-inducible gene expression under hypoxic conditions.     

Verification of the antidiabetic effects of cinnamon (Cinnamomum zeylanicum) using insulin-uncontrolled type 1 diabetic rats and cultured adipocytes

It has long been believed that an intake of cinnamon (Cinnamomum zeylanicum) alleviates diabetic pathological conditions. However, it is still controversial whether the beneficial effect is insulin-dependent or insulin-mimetic. This study was aimed at determining the insulin-independent effect of cinnamon. Streptozotocin-induced diabetic rats were divided into four groups and orally administered with an aqueous cinnamon extract (CE) for 22 d. The diabetic rats that had taken CE at a dose of more than 30 mg/kg/d were rescued from their hyperglycemia and nephropathy, and these rats were found to have upregulation of uncoupling protein-1 (UCP-1) and glucose transporter 4 (GLUT4) in their brown adipose tissues as well as in their muscles. This was verified by using 3T3-L1 adipocytes in which CE upregulates GLUT4 translocation and increases the glucose uptake. CE exhibited its anti-diabetic effect independently from insulin by at least two mechanisms: i) upregulation of mitochondrial UCP-1, and ii) enhanced translocation of GLUT4 in the muscle and adipose tissues.     

Diallyl trisulfide suppresses the proliferation and induces apoptosis of human colon cancer cells through oxidative modification of beta-tubulin

Allyl sulfides are characteristic flavor components obtained from garlic. These sulfides are thought to be responsible for their epidemiologically proven anticancer effect on garlic eaters. This study was aimed at clarifying the molecular basis of this anticancer effect of garlic by using human colon cancer cell lines HCT-15 and DLD-1. The growth of the cells was significantly suppressed by diallyl trisulfide (DATS, HCT-15 IC50 = 11.5 microM, DLD-1 IC50 = 13.3 microM); however, neither diallyl monosulfide nor diallyl disulfide showed such an effect. The proportion of HCT-15 and that of DLD-1 cells residing at the G1 and S phases were decreased by DATS, and their populations at the G2/M phase were markedly increased for up to 12 h. The cells with a sub-G1 DNA content were increased thereafter. Caspase-3 activity was also dramatically increased by DATS. Fluorescence-activated cell sorter analysis performed on the cells arrested at the G1/S boundary revealed cell cycle-dependent induction of apoptosis through the transition of the G2/M phase to the G1 phase by DATS. DATS inhibited tubulin polymerization in an in vitro cell-free system. DATS disrupted microtubule network formation of the cells, and microtubule fragments could be seen at the interphase. Peptide mass mapping by liquid chromatography-tandem mass spectrometry analysis for DATS-treated tubulin demonstrated that there was a specific oxidative modification of cysteine residues Cys-12beta and Cys-354beta to form S-allylmercaptocysteine with a peptide mass increase of 72.1 Da. The potent antitumor activity of DATS was also demonstrated in nude mice bearing HCT-15 xenografts. This is the first paper describing intracellular target molecules directly modified by garlic components.     

The root tip and accelerating region suppress elongation of the decelerating region without any effects on cell turgor in primary roots of maize under water stress

To identify the region in which a root perceives a decrease in the ambient water potential and changes its elongation rate, we applied two agar blocks (1 x 1 x 1 mm(3)) with low water potential bilaterally to primary roots of maize (Zea mays) at various positions along the root. When agar blocks with a water potential of -1.60 MPa (-1.60-MPa blocks) or lower were attached to a root tip, the rate of elongation decreased. This decrease did not result from any changes in the water status of elongating cells and was not reversed when the -1.60-MPa blocks were replaced by -0.03-MPa blocks. The rate decreased slightly and was unaffected, respectively, when -1.60-MPa blocks were applied to the so-called decelerating region of the elongating zone and the mature region. However, the rate decreased markedly and did not recover for several hours at least when such blocks were attached to the accelerating region. In this case, the turgor pressure of the elongating cells decreased immediately after the application of the blocks and recovered thereafter. The decrease in elongation rate caused by -1.60-MPa blocks applied to the root tip was unaffected by additional -0.03-MPa blocks applied to the accelerating region and vice versa. We concluded that a significant reduction in root growth could be induced by water stress at the root tip, as well as in the accelerating region of the elongating zone, and that transmission of some signal from these regions to the decelerating region might contribute to the suppression of cell elongation in the elongation region.