Detection of nivalenol genotoxicity in cultured cells and multiple mouse organs by the alkaline single-cell gel electrophoresis assay

The effects of upper airway (UAW) flows and pressures on breathing pattern and respiratory muscle activities were studied in anesthetized rats breathing through a tracheostomy. A steady flow (approximately 1000 ml/kg/min) of cold dry air, or cold wet air, or warm wet air was passed through the UAW, in the expiratory direction for approximately 20 sec (20-40 sec). In other trials positive or negative pressure was applied to the isolated UAW for a similar duration. There was a marked prolongation of the expiratory duration and decreases in peak inspiratory flow, tidal volume, and peak diaphragm electromyogram (EMG) activity in response to cold dry airflow. The responses to cold wet air were reduced but still significant. Warm wet air had no effect on breathing. These responses show that UAW cooling and drying depress breathing in the rat and that cooling itself could cause the inhibition of breathing. Negative pressure induced substantial increases in genioglossus and laryngeal inspiratory activity while positive pressure caused a decrease in genioglossus activity. Positive pressure also increased expiratory time while negative pressure increased inspiratory time. These results confirm the functional role of the UAW dilating muscles in preventing UAW from collapse in rats.     

Degradation of polyetherurethane by subcutaneous implantation into rats. I. Molecular weight change and surface morphology

The pharmacological characteristics of the 3-oxamethano-prostaglandin I1 compound (+)-methyl [2-[(2R,3aS,4R,5R,6aS)-octahydro-5-hydroxy-4- [(E)-(3S,5S)-3-hydroxy-5-methyl-1-nonenyl]-2-pentalenyl]etho xy] acetate (SM-10902, CAS 139403-31-9), a novel stable analogue of prostacyclin and its free acid, SM-10906, were studied. SM-10902 was rapidly deesterified to its free acid in rabbit and human serum. SM-10902 and SM-10906 exhibited antiplatelet potency against ADP-induced aggregation in rabbit and human platelets. In the presence of diisopropyl fluorophosphate, an esterase inhibitor, the antiplatelet activity of SM-10902 was markedly reduced, to much less than that of SM-10906. SM-10906 inhibited platelet aggregation induced by various inducers in several species and enhanced the cyclic AMP (cAMP) level in human platelets. These activities were nearly equal to those of prostaglandin (PG) E1 and less than those of PGI2. SM-10906 relaxed isolated rabbit mesenteric and bovine coronary arteries, and elevated the cAMP level in bovine coronary arteries. SM-10906 given intravenously exhibited a sustained reduction in blood pressure based on vasodilation in ganglion-blocked, angiotensin II-supported rats. SM-10902 applied to the guinea-pig auricles increased the skin temperature, but SM-10906 and PGI2 showed no such effect. In conclusion, SM-10902, which is considered to be a prodrug of SM-10906, was suggested to exert its anti-platelet and vasodilator activities through the increase of cAMP. Since SM-10902 penetrates well into the skin, it may be useful as an external preparation to improve peripheral circulatory insufficiency.     

Preoperative staging of endometrial carcinoma: diagnostic effect of T2-weighted fast spin-echo MR imaging

PURPOSE: To evaluate the usefulness of T2-weighted fast spin-echo magnetic resonance (MR) imaging with a 512 x 256 matrix for assessment of the preoperative stage of endometrial carcinoma. MATERIALS AND METHODS: Twenty-eight women with histopathologically proved endometrial carcinoma underwent preoperative T2-weighted fast spin-echo, dynamic T1-weighted fast spin-echo, and postcontrast T1-weighted spin-echo MR imaging with a phased-array surface coil. The uterine long-axis planes in each sequence were reviewed at separate sessions by three radiologists blinded to the histopathologic data. RESULTS: For the diagnosis of myometrial invasion, no statistically significant differences were found among T2-weighted imaging, dynamic imaging, and postcontrast T1-weighted imaging. For the diagnosis of deep myometrial invasion, T2-weighted and dynamic images showed higher specificity than postcontrast T1-weighted images (T2-weighted, 89%; dynamic, 88%; and postcontrast T1-weighted, 80%). For cervical invasion, T2-weighted and dynamic images showed larger areas under receiver operating characteristic curves than did postcontrast T1-weighted images (T2-weighted, 0.78; dynamic, 0.71; and postcontrast T1-weighted, 0.67). CONCLUSION: T2-weighted imaging is useful for identifying the stage of endometrial carcinoma.     

Characterization of heparinase from an oral bacterium Prevotella heparinolytica

The idea that amphotericin B (AmB) may not require sterols to form ion selective channels has recently been criticized on the grounds that egg phospholipids commonly used in experiments may contain small amounts of sterol which associate with AmB to form AmB/sterol pore channel structures. It was recently shown in this laboratory that modest osmotic stress can enhance the formation of AmB channels in sterol-free egg phosphatidylcholine (eggPC) membranes. We have tested AmB's ability to form ion channels/defects in synthetic palmitoyl oleoyl (POPC), dieicosenyl (DEPC) and natural eggPC osmotically stressed large unilamellar vesicles (LUV) using pyranine fluorescence detected ion/H+ exchange. These sterol-free POPC LUV exhibit greatly increased sensitivity to cation selective AmB channel formation when osmotically stressed; even more than eggPC. Under these stressed conditions, AmB activity was observed at [AmB]/POPC ratios as low as 3.5x10(-4), corresponding to about 34 AmB molecules/vesicle. DEPC vesicles were almost completely unresponsive, demonstrating a strong bilayer thickness dependence. These results prove conclusively that AmB can form sterol-free channels and do so within therapeutic concentration ranges (>0.5-10x10(-6) M) in a stress-dependent manner. This phenomenon may allow us to use osmotic stress changes in simple model systems to spectroscopically isolate and characterize the thus-far elusive AmB channel forming aggregate. In addition, this stress dependence may be responsible for the potentiation of renal toxicity of AmB in the ascending branch of the loop of Henle which is under greatest osmotic stress.     

Optical nonlinear characteristics of a side-injectionlight-controlled laser diode with a multiple-quantum-well saturableabsorption region

A multiple-quantum-well bistable laser-diode structure in which the input signal is launched into the main laser through an orthogonally configured subwaveguide is proposed. Insensitivity to input light wavelength (28 nm of 3 dB bandwidth) and high isolation of input versus output (over 30 dB) are observed. In addition, reflection of input signal is negligibly small     

Modulation of dihydroxy-di-n-propylnitrosamine-induced liver lesion development in Opisthorchis-infected Syrian hamsters by praziquantel treatment in association with butylated hydroxyanisole or dehydroepiandrosterone administration

The effects of praziquantel coupled with dehydroepiandrosterone (DHEA) or butylated hydroxyanisole (BHA) administration 16 weeks subsequent to dihydroxy-di-n-propylnitrosamine (DHPN) treatment and infection with Opisthorchis viverrini (OV) on lesion development in the liver of Syrian hamsters were investigated. Animals were given 80 OV metacercariae and then two i.p. injections of DHPN (500 mg/kg body weight) 4 and 5 weeks thereafter. At week 16, groups received praziquantel (250 mg/kg, i.g.) and were placed on normal diet or diet supplemented with BHA (1%) or DHEA (0.6%) until they were killed at week 24. Histopathological assessment revealed that, whereas antihelminthic treatment alone resulted in a clear reduction in hepatocellular lesion development, effects on cholangiocellular lesions were equivocal. BHA and DHEA, in contrast, were both associated with a significant reduction in frequency of cholangiofibrosis and cholangiocellular carcinoma. The former chemical, however, increased the numbers of liver nodules while the hormone brought about a decrease as well as a shift in the phenotype of the lesions. The results thus indicate that although cholangiocellular lesion development may, unlike generation of hepatocellular nodules, be to a certain extent independent of the continued presence of parasite, it can be influenced by exogenous treatments.     

煅烧炉用喷射耐火料的近期发展趋向

开发了一种干式喷射隔热材料,其热导率与隔热板一样低.它正取代普通的隔热板,因它的安装方便,工作环境较好.另外,我们已开发了新的湿式喷射料体系,它效率高,工作环境好.     

Lysophosphatidic acid-induced association of SHP-2 with SHPS-1: roles of RHO, FAK, and a SRC family kinase

SHPS-1 is an approximately 120 kDa glycosylated receptor like protein that contains three immunoglobulin-like domains in its extracellular region as well as four potential tyrosine phosphorylation and SRC homology 2 (SH2) domain binding sites in its cytoplasmic region. Lysophosphatidic acid (LPA) stimulated the rapid tyrosine phosphorylation of SHPS-1 and its subsequent association with SHP-2, a protein tyrosine phosphatase containing SH2 domains in Rat-1 fibroblasts. LAP-induced tyrosine phosphorylation of SHPS-1 was inhibited by Clostridium botulinum C3 exoenzyme (which inactivates RHO) but not by pertussis toxin. The protein kinase C activator phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) also stimulated tyrosine phosphorylation of SHPS-1; however, down-regulation of protein kinase C by prolonged exposure of cells to TPA did not affect LAP-induced tyrosine phosphorylation of SHPS-1. LPA-induced tyrosine phosphorylation of SHPS-1 was markedly reduced in either focal adhesion kinase (FAK)-deficient mouse cells or CHO cells overexpressing the tyrosine kinase CSK. Overexpression of a catalytically inactivate SHP-2 markedly inhibited MAP kinase activation in response to low concentrations of LPA in CHO cells, whereas overexpression of a wild-type SHPS-1 did enhance this effect of LPA. Furthermore, MAP kinase activation in response to a low concentration of LPA was inhibited by botulinum C3 exoenzyme. These results indicate that LPA-induced tyrosine phosphorylation of SHPS-1 and its association with SHP-2 may be mediated by a RHO-dependent pathway that includes FAK and a SRC family kinase. Thus, in addition to its role in receptor tyrosine kinase-mediated MAP kinase activation, the formation of a complex between SHPS-1 and SHP-2 may, in part, play an important role in the activation of MAP kinase in response to low concentrations of LPA.     

Tunable liquid-crystal Fabry-Perot interferometer filter forwavelength-division multiplexing communication systems

We explain how to obtain the bandwidth and tunable range required for wavelength-division multiplexing communication systems and how to design tunable liquid-crystal Fabry-Perot interferometer filters. The main factors determining the performance are liquid-crystal loss, mirror loss, surface roughness, and parallelism, as well as mirror reflectivity and cavity gap. Experimental results closely agree with the designed performance. Temperature dependence, response time, acceptable input power, and reliability are investigated. Pigtailed polarization-independent filter modules with a Peltier controller are made and are shown to have low polarization dependence (<0.3 dB), low driving voltage (<15 V), and compact size, as well as a narrow bandwidth (0.3 nm), high finesse of 189, and large tunable range (50 nm)     

A hidden immunoglobulin G2 in patients with rheumatoid arthritis detected by nuclear magnetic resonance

OBJECTIVE: The ratios of immunoglobulin (Ig) G1 and IgG2 in patients with rheumatoid arthritis (RA) were examined by nuclear magnetic resonance (NMR) and the results were compared to data obtained by ELISA. METHODS: The IgG of 11 patients with RA were prepared with a DE-52 column and the specific signals for IgG1 and IgG2 were measured by NMR. The ratios of IgG1 and IgG2 were determined by the intensity of this signal. The samples were also measured by ELISA. RESULTS: The ratios of IgG2 in patients with RA measured by NMR were increased significantly compared to controls. However, there were no significant differences in the data determined by ELISA. Thus, a discrepancy exists in the analysis of IgG2 ratios between NMR and ELISA methods. CONCLUSION: There was a discrepancy in the IgG2 ratios of patients with RA between NMR and ELISA methods, and we attribute this to a conformational difference in IgG2 in patients with RA.