Hepatocyte growth factor enhances adhesion of breast cancer cells to endothelial cells in vitro through up-regulation of CD44

For cancer metastasis, tumor cells present in the circulation must first adhere to the endothelium. Integrins play a central role in leukocyte adhesion to the endothelium and subsequent migration into tissues. The majority of tumor cells derived from solid cancers, including breast cancer, do not express integrins. We investigated the mechanisms of adhesion and transendothelial migration of cancer cells using breast carcinoma cell lines. Our results showed the following features of breast cancer cells: (1) HGF stimulated breast cancer cells by up-regulating CD44 expression in a concentration-dependent manner. (2) the maximum level of HGF-induced CD44 up-regulation on breast cancer cell lines occurred within 3 h. (3) HGF-induced up-regulation of CD44 was mediated by the tyrosine kinase signaling pathway. (4) HGF induced CD44-mediated adhesion of tumor cell lines to bone marrow-derived endothelial cells. (5) HGF did not change rolling of breast cancer cell lines on bone marrow-derived endothelial cells, but enhanced firm adhesion of cancer cells on endothelial cells under shear stress conditions. (6) HGF increased transendothelial migration of cancer cells. Our results indicate that HGF stimulates CD44-mediated adhesion of breast cancer cells to bone marrow-derived endothelial cells, which subsequently results in transendothelial migration of tumor cells. These results suggest that CD44 may confer the metastatic properties of breast cancer cells and, therefore, could be used as a target in future molecular cancer therapy.     

Molecular heterogeneity of heat-stable toxin-producing and non-producing Escherichia coli O25 strains isolated in Japan

Escherichia coli O25 strains that produce heat-stable toxin (ST) have been recently isolated in Japan, and epidemiological study of this type of enterotoxigenic E. coli is required. In this study the heterogeneity of 16 ST-producing and non-producing strains of E. coli O25 was investigated. All eight ST-producing strains were shown to have STIb gene, and seven of them had similar profiles of plasmids, ladder-banding of LPS in SDS-polyacrylamide gel electrophoresis, and chromosomal DNA digestions in pulsed-field gel electrophoresis (PFGE). In contrast, ST-non-producing strains were more heterogeneous in all parameters examined. PFGE of the digested chromosomal DNA with several restriction enzymes was proved to be an effective procedure to compare the closely related strains of E. coli O25.     

Occurrence of an alpha-galacturonosyl-ceramide in the dioxin-degrading bacterium Sphingomonas wittichii

The chemical structure of two glycosphingolipids (GSLs) found in the dioxin-degrading bacterium Sphingomonas wittichii strain RW1 was investigated by means of mass spectrometry and (1)H-nuclear magnetic resonance spectroscopy. One of the GSLs was alpha-D-glucuronosyl-ceramide, commonly present in Sphingomonas spp., and the other was proved to be alpha-D-galacturonosyl-ceramide, whose sugar configuration has not been reported before. In both GSLs the ceramide portion was composed of myristic acid or 2-hydroxy-myristic acid as the fatty acid, and 2-amino-1,3-octadecanediol or 2-amino-cis-13,14-methylene-1,3-eicosanediol as the dihydrosphingosine.     

Regeneration of hippocampal pyramidal neurons after ischemic brain injury by recruitment of endogenous neural progenitors

The adult brain is extremely vulnerable to various insults. The recent discovery of neural progenitors in adult mammals, however, raises the possibility of repairing damaged tissue by recruiting their latent regenerative potential. Here we show that activation of endogenous progenitors leads to massive regeneration of hippocampal pyramidal neurons after ischemic brain injury. Endogenous progenitors proliferate in response to ischemia and subsequently migrate into the hippocampus to regenerate new neurons. Intraventricular infusion of growth factors markedly augments these responses, thereby increasing the number of newborn neurons. Our studies suggest that regenerated neurons are integrated into the existing brain circuitry and contribute to ameliorating neurological deficits. These results expand the possibility of novel neuronal cell regeneration therapies for stroke and other neurological diseases.     

Effects of static stress on the mechanical properties of cultured collagen fascicles from the rabbit patellar tendon

In-vitro tissue culture experiments were performed to study the effects of static stress on the mechanical properties of collagen fascicles obtained from the rabbit patellar tendon. After collagen fascicles having the diameter of approximately 300 microm were cultured for 1 and 2 wk under static stress between 0 and 3 MPa, their mechanical properties and crimp morphology were determined using a micro-tensile tester and a light microscope, respectively. The tensile strength and tangent modulus of the fascicles were significantly decreased by culture under no load compared to control fascicles. A statistically significant correlation, which was described by a quadratic curve, was observed between applied stress and tensile strength. The maximum tensile strength (16.7 MPa) was obtained at the applied stress of 1.2 MPa; the strength was within a range of control values. There was a similar correlation between applied stress and tangent modulus, and the modulus was maintained at control level under 1.3 MPa stress. The stress of 1.2 to 1.3 MPa is equivalent to approximately 50 percent of the peak stress developed in the intact rabbit patellar tendon by running. Strain at failure of cultured collagen fascicles was negatively correlated with applied stress, and that at 1.2 to 1.3 MPa stress was almost the same as the control value. Crimp morphology in the fascicles cultured under about 1.2 MPa stress was similar to that in control fascicles. These results indicate that cultured collagen fascicles change the mechanical properties and structure in response to static tensile stress. In addition, their mechanical properties and structure are maintained at control level if the static stress of 50 percent of in-vivo peak stress is applied.     

Diagnostic evaluation of 2', 5'-oligoadenylate synthetase activities and antibodies against Epstein-Barr virus and Coxiella burnetii in patients with chronic fatigue syndrome in Japan

To investigate the association of viral infections with chronic fatigue syndrome (CFS), we assayed 2', 5'-oligoadenylate synthetase (2-5AS) activities in peripheral blood mononuclear cells from CFS patients in Japan. These patients were diagnosed in two hospitals, H1 and H2, located in different areas of the country. The activities were detected in 19 (86%) and 7 (32%) of each of the 22 patients in H1 and H2, respectively, while they were detected in only four (11%) out of the 38 healthy controls. IFN-alpha was similarly detected in a few CFS patients and healthy controls. We also assayed the antibody titers against Epstein-Barr virus (EBV) and Coxiella burnetii in these patients. The EBV anti-EA-IgG antibodies were detected in two (9%) and seven (32%) of each of the 22 patients in H1 and H2, respectively. Anti-C. burnetii IgG antibodies were detected in six (27%) out of 22 patients in H1 but not in 22 patients in H2, while they were detected in one (11%) of the nine healthy controls. Some CFS patients may be associated with EBV or C. burnetii infection. There were some statistical correlations between the 2-5AS activities and antibody titers of EA-IgG (P < 0.05, Student's t-test) but not to the antibody titers of C. burnetii. The up-regulation of 2-5AS activities suggests immunological dysfunctions with some virus infections in the CFS patients. Our results indicate that 2-5AS activities are useful for a diagnostic marker of CFS and for exploring the complicated pathogenesis of CFS.     

Beta 3-adrenergic receptor is involved in feeding regulation in chicks

We examined whether the brain beta 3-adrenergic receptor (B3-AR) is involved in the feeding regulation of chicks. Intracerebroventricular (ICV) injection of BRL37344, a B3-AR agonist, reduced food intake of chicks under ad libitum, but not fasting, feeding conditions. The ICV injection of BRL37344 did not affect chick posture or locomotion activity suggesting that BRL37344 inhibited feeding without induction of sleep-like behavior as caused by norepinephrine. Furthermore, the rectal temperature increased following the ICV injection of BRL37344. Intraperitoneal administration of BRL37344 did not reduce food intake under ad libitum feeding condition. The present study demonstrated that the brain B3-AR is involved in the inhibition of feeding in chicks. We also suggested that activation of the brain affects the energy metabolism in chicks.     

Properties of a novel extracellular cell-free ice nuclei from ice-nucleating Pseudomonas antarctica IN-74

Some ice-nucleating bacterial strains, including Pantoea ananatis (Erwinia uredovora), Pseudomonas fluorescens, and Pseudomonas syringae isolates, were examined for the ability to shed ice nuclei into the growth medium. A novel ice-nucleating bacterium, Pseudomonas antarctica IN-74, was isolated from Ross Island, Antarctica. Cell-free ice nuclei from P. antarctica IN-74 were different from the conventional cell-free ice nuclei and showed a unique characterization. Cell-free ice nuclei were purified by centrifugation, filtration (0.45 microm), ultrafiltration, and gel filtration. In an ice-nucleating medium in 1 liter of cell culture, maximum growth was obtained with the production of 1.9 mg of cell-free ice nuclei. Ice nucleation activity in these cell-free ice nuclei preparations was extremely sensitive to pH. It was demonstrated that the components of cell-free ice nuclei were protein (33%), saccharide (12%), and lipid (55%), indicating that cell-free ice nuclei were lipoglycoproteins. Also, carbohydrate and lipid stains showed that cell-free ice nuclei contained both carbohydrate and lipid moieties.     

Stimulatory effect of a dietary casein phosphopeptide preparation on the mucosal IgA response of mice to orally ingested lipopolysaccharide from Salmonella typhimurium

The effect on immunoglobulin production of a commercially available casein phosphopeptide preparation (CPP-III) consisting mainly of bovine alpha s2-casein (1-32) and beta-casein (1-28) in mice that had orally ingested lipopolysaccharide (LPS) from Salmonella typhimurium was investigated. No significant difference in body weight gain was observed between the mice fed on the CPP-III-added diet and those fed on the control diet. The mice fed on the CPP-III-added diet exhibited similar serum and intestinal IgG, IgM, and IgE responses towards LPS to those fed on the control diet. In contrast, fecal and intestinal anti-LPS IgA and total IgA in mice fed on the CPP-III-added diet were significantly higher than in those fed on the control diet. Spleen cells from mice fed on the CPP-III-added diet produced larger amounts of IgA, IL-5, and IL-6 than cells from mice fed on the control diet. These results suggest that dietary casein phosphopeptide may protect a host from invasion of the intestinal mucosa by food-born pathogenic microorganisms.