Inhibition of tumor invasion and metastasis by calcium spirulan (Ca-SP), a novel sulfated polysaccharide derived from a blue-green alga, Spirulina platensis

We have investigated the effect of calcium spirulan (Ca-SP) isolated from a blue-green alga, Spirulina platensis, which is a sulfated polysaccharide chelating calcium and mainly composed of rhamnose, on invasion of B16-BL6 melanoma, Colon 26 M3.1 carcinoma and HT-1080 fibrosarcoma cells through reconstituted basement membrane (Matrigel). Ca-SP significantly inhibited the invasion of these tumor cells through Matrigel/fibronectin-coated filters. Ca-SP also inhibited the haptotactic migration of tumor cells to laminin, but it had no effect on that to fibronectin. Ca-SP prevented the adhesion of B16-BL6 cells to Matrigel and laminin substrates but did not affect the adhesion to fibronectin. The pretreatment of tumor cells with Ca-SP inhibited the adhesion to laminin, while the pretreatment of laminin substrates did not. Ca-SP had no effect on the production and activation of type IV collagenase in gelatin zymography. In contrast, Ca-SP significantly inhibited degradation of heparan sulfate by purified heparanase. The experimental lung metastasis was significantly reduced by co-injection of B16-BL6 cells with Ca-SP. Seven intermittent i.v. injections of 100 microg of Ca-SP caused a marked decrease of lung tumor colonization of B16-BL6 cells in a spontaneous lung metastasis model. These results suggest that Ca-SP, a novel sulfated polysaccharide, could reduce the lung metastasis of B16-BL6 melanoma cells, by inhibiting the tumor invasion of basement membrane probably through the prevention of the adhesion and migration of tumor cells to laminin substrate and of the heparanase activity.     

Labial adhesion presenting as urinary incontinence and dysuria in a postmenopausal woman: a case report

A 68-year-old woman admitted to our hospital complaining of urinary incontinence and dysuria. On examination, the labia were found to be fused extensively, with a pinhole opening at the midline. Under spinal anesthesia, the adhesion was clearly separated with the Hegar's dilator. There remains no recurrence in this patient following therapy. The labial adhesion was considered to be an acquired disease caused by infection, trauma in the genitalia, or sexless life, according to hypoestrogenism.     

Visual Search Asymmetry With Uncertain Targets.

The underlying mechanism of search asymmetry is still unknown. Many computational models postulate top-down selection of target-defining features as a crucial factor. This feature selection account implies, and other theories implicitly assume, that predefined target identity is necessary for search asymmetry. The authors tested the validity of the feature selection account using a singleton search task without a predefined target. Participants conducted a target-defined and a singleton search task with a circle (O) and a circle with a vertical bar (Q). Search asymmetry was observed in both tasks with almost identical magnitude. The results were not due to trial-by-trial feature selection, because search asymmetry persisted even when the target was completely unpredictable. Asymmetry in the singleton search was also observed with more complex stimuli, Kanji characters. These results suggest that feature selection is not necessary for search asymmetry, and they impose important constraints on current visual search theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Production of -lyxose from -glucose by microbial and enzymatic reactions

-Arabitol was first prepared from -glucose using Candida famata R28. The reaction gave 5.0% -arabitol from 10.0% -glucose. -Arabitol was then almost completely converted to -xylulose using Acetobacter aceti IFO 3281. Finally, -lyxose was prepared from -xylulose enzymatically using -ribose isomerase from toluene-treated cells of Acinetobacter sp. strain DL-28. The isomerization reaction progressed steadily and the concentration of -xylulose increased from 1.0 to 10.0%. About 70% of -xylulose was converted to -lyxose in all cases. Separation of residual -xylulose from the reaction mixture is very difficult to achieve by column chromatography, but -xylulose could be selectively degraded easily using Saccharomyces cerevisiae IFO 0841. The product was crystallized and was confirmed to be -lyxose by HPLC, ¹³C-NMR spectra, IR spectra analysis, and optical rotation measurement.     

Viscosity measurement of gelcasting slurry during in-situ gelation by a micro X-ray CT scan system

This paper reports the use of a micro X-ray CT scan system to measure the viscosity increase during in-situ gelation of a gelcasting slurry. Three small steel balls were dropped in the slurry at a desired time interval after the addition of the gelling agent, while being monitored by the CT scan system. It was determined that the plot of the logarithm of the calculated viscosities based on the settling velocity of the falling ball versus the gelation time can be classified into three regions with increasing slopes. The first region is designated as the idle time during which the gelcasting slurry can be further processed and cast into a mold. The second region is the onset of gelation during which the polymer networks start to form with a gradual increase in the viscosity, whereas the third region is attributed to the increased concentration of the polymerized networks as typified by the significant increase in the slurry viscosity. Moreover, the falling ball method was found to be more sensitive to detecting the onset of gel formation in the gelcasting slurry than stress-controlled rheometric analyses.     

Metabolic and hormonal mechanisms of mineral metabolic adaptation to induced hypokinetics in rats

During simulated hypokinetics, many biological functions have a tendency to stabilize at different levels with the passing of time. In this experiment, hypokinetic exposure was induced in albino rats by the suspension method for 5 weeks. A new plateau in urinary K+ excretion was attained during the third week, after a transient decrease during the first week. Since the formation of this steady plateau is considered a manifestation of the adaptation of this function, the hypokinetic exposure period was divided into a prestabilized phase and a stabilized phase. To ascertain the biochemical mechanisms of this adaptation process, the effects of aldosterone and anti-aldosterone substances (e.g., tetracycline) on K+ and Na+ excretion patterns in each phase were investigated. Decreasing aldosterone activity in the prestabilized phase and increasing activity in the stabilized phase are recognized as one of the main factors in the renal adaptation process to hypokinetics.     

Nano-optical probing of exciton wave-functions confined in a GaAs quantum dot

We have enhanced the performance of near-field scanning optical microscopy (NSOM) in terms of the spatial resolution and the sensitivity in signal detection. A careful preparation of an aperture-NSOM probe provides us with a spatial resolution as high as 30 nm in fluorescence imaging spectroscopy. We have applied this technique to map out the center-of-mass wave functions of an exciton confined in a GaAs quantum dot (a monolayer-high island formed in a quantum well). The spatial profile of the exciton emission, which reflects the shape of the island, differs from that of biexciton emission, due to different distributions of the polarization field for the exciton and biexciton recombinations. A theoretical calculation of the spatial distribution of the polarization field quantitatively reproduced the experimental result. Furthermore, mapping of an excited state wave-function with a node structure is also demonstrated. The novel technique can be extensively applied to wave-function engineering in the design and fabrication of quantum devices.     

Effect of oxygen concentration on nitrogen removal by Nitrosomonas europaea and Paracoccus denitrificans immobilized within tubular polymeric gel

Tubular gel reactors containing Nitrosomonas europaea and Paracoccus denitrificans, which remove nitrogen from solutions through a process of nitrification and denitrification, require oxygen for ammonia oxidation, the first and rate-limiting step in the process. To accelerate ammonia oxidation, high concentrations of oxygen were applied to the reactors instead of air. Although a 50% O2:N2 gas mixture and pure oxygen were both toxic to free N. europaea cells, they actually accelerated ammonia oxidation by N. europaea immobilized within the tubular gel. Indeed, the rate of ammonia oxidation by a tube exposed to pure oxygen was twice that of one exposed to 20% O2. When the distribution of N. europaea cells within the tubes was investigated using a fluorescently-labeled antibody, colonies were found on the external surface of the tube exposed to 20% O2, but were located at a depth of 120-300 microm from the external surface in the case of the tube exposed to pure oxygen. The region between the external surface of the gel and the colonies apparently acted as a barrier, reducing the diffusion of oxygen and thus protecting the cells from oxygen cytotoxicity.     

Inhibition of tumor cell adhesion and metastasis

Since the establishment of an experimental metastasis model using some tumor metastatic cell lines, progress has been made in basic studies on tumor metastasis. In addition, the complex mechanisms of tumor metastasis have been elucidated by the cellular and molecular studies. Here we focus our attention on the relationship between tumor metastasis and cellular adhesiveness, a factor which is a critical determinant in tumor progression and metastasis. The roles of cell adhesive molecules in the metastatic process are also described. This type of study is invaluable in understanding the molecular and regulatory mechanisms of tumor metastasis. We also report the antimetastatic effect of some polypeptides of fibronectin in the extracellular matrices, poly (RGD) and recombinant fusion peptide containing cell- and heparin-binding domain of fibronectin (CH-271) in regulating the mechanism of tumor cell adhesion.