Anticarcinogenic antioxidants as inhibitors against intracellular oxidative stress

Oxidative stress has been implicated in the pathogenesis of numerous diseases, including cancer. In the present study, the protective effect of natural antioxidants, such as quercetin and tea polyphenols, on intracellular oxidative stress was studied. Here we report a novel function of quercetin and tea polyphenols, as potential inhibitors of 4-hydroxy-2-nonenal (HNE)-induced intracellular oxidative stress and cytotoxicity. In rat liver epithelial RL34 cells, a potent electrophile HNE dramatically induced the productions of reactive oxygen species (ROS), which correlated well with the reduction in cell viability. We found that quercetin and tea polyphenols, such as epigallocatechin gallate and theaflavins and their gallate esters, significantly inhibited the HNE-induced ROS production and cytotoxicity. In addition, HNE induced a transient decrease in the mitochondrial membrane potential (delta psi), which was also retarded by the antioxidants. These data suggest that the antioxidants, such as quercetin and tea polyphenols, are inhibitors against mitochondrial ROS production.

Mode of action of the ecdysone agonist tebufenozide (RH-5992), and an exclusion mechanism to explain resistance to it

Spruce budworm larvae (Choristoneura fumiferana) upon ingesting tebufenozide (RH-5992) stop feeding and go into a precocious, incomplete molt, leading eventually to death. Like 20-hydroxyecdysone (20E), tebufenozide also acts at the receptor level and transactivates the expression of up-regulated genes but, because of its persistence, the down-regulated genes that are normally expressed in the absence of 20E are not expressed. While tebufenozide is lepidopteran-specific, an analog, RH-5849, is effective on dipterans. This is reflected in the respective effects of the two compounds on Cf-203 (C. fumiferana--203), a lepidopteran cell line and Dm-2 (Drosophila melanogaster--2), a dipteran cell line. Cf-203 cells accumulated [14C]tebufenozide and expressed CHR3 (Choristoneura hormone receptor 3), but Dm-2 cells excluded the material and did not express DHR3 (Drosophila hormone receptor 3). Using yeast ABC (ATP binding cassette) transporter mutants, we determined that PDR5 (pleiotropic drug resistance 5) was responsible for the exclusion. We discovered recently that older instars of the white-marked tussock moth (Orgyia leucostigma) are resistant to tebufenozide, perhaps as a result of such an exclusion system. We are currently cloning PDR5 (pleiotropic drug resistance 5), which is an essential step in studying the resistance mechanism.

Increased inducible nitric oxide synthase expression contributes to myocardial dysfunction and higher mortality after myocardial infarction in mice

BACKGROUND

Inducible nitric oxide synthase (iNOS) is expressed in the myocardium after myocardial infarction (MI) and in heart failure. Its pathophysiological role in these conditions, however, is not clear. We hypothesized that increased NO production from iNOS expression causes myocardial dysfunction and results in higher mortality after MI.

METHODS AND RESULTS

MI was induced by left coronary artery ligation in iNOS(-/-) mutant and wild-type mice. Mortality was followed up for 30 days. MI resulted in a significant increase in mortality in both iNOS(-/-) and wild-type mice compared with sham operation (P<0.01). Mortality was significantly decreased and LV myocardial contractility was increased, however, in iNOS(-/-) mice compared with the wild-type mice (P<0.05). Five days after MI, myocardial iNOS mRNA expression, plasma nitrate and nitrite concentrations, and myocardial and plasma nitrotyrosine levels were significantly increased in wild-type compared with iNOS(-/-) mutant mice (P<0.05). Both basal LV +dP/dt and its response to dobutamine were significantly increased in iNOS(-/-) compared with the wild-type mice (P<0.05).

CONCLUSIONS

Increased NO production from iNOS expression contributes to myocardial dysfunction and mortality after MI in mice.

Methylation of histone H4 at arginine 3 facilitating transcriptional activation by nuclear hormone receptor

Acetylation of core histone tails plays a fundamental role in transcription regulation. In addition to acetylation, other posttranslational modifications, such as phosphorylation and methylation, occur in core histone tails. Here, we report the purification, molecular identification, and functional characterization of a histone H4-specific methyltransferase PRMT1, a protein arginine methyltransferase. PRMT1 specifically methylates arginine 3 (Arg 3) of H4 in vitro and in vivo. Methylation of Arg 3 by PRMT1 facilitates subsequent acetylation of H4 tails by p300. However, acetylation of H4 inhibits its methylation by PRMT1. Most important, a mutation in the S-adenosyl-l-methionine-binding site of PRMT1 substantially crippled its nuclear receptor coactivator activity. Our finding reveals Arg 3 of H4 as a novel methylation site by PRMT1 and indicates that Arg 3 methylation plays an important role in transcriptional regulation.

Attenuation of compensatory right ventricular hypertrophy and heart failure following monocrotaline-induced pulmonary vascular injury by the Na+-H+ exchange inhibitor cariporide

Pulmonary hypertension results in compensatory right ventricular (RV) hypertrophy. We studied the role of the Na+-H+ exchange (NHE) in the latter process by determining the effect of the NHE-1 inhibitor cariporide after monocrotaline-induced pulmonary artery injury. Sprague-Dawley rats received a control or cariporide diet for 7 days, at which time they were administered either monocrotaline (60 mg/kg) or its vehicle. Twenty-one days later, monocrotaline control, but not cariporide-fed animals, demonstrated increased RV weights and cell size of 65 and 52%, respectively. Monocrotaline alone significantly increased RV systolic pressure and end diastolic pressure by 70 and 94%, respectively, whereas corresponding values with cariporide were significantly reduced to 33 and 42%. Central venous pressure increased by 414% in control animals, which was significantly reduced by cariporide. Monocrotaline treatment produced a decrease in cardiac output of 28 and 8% in the absence or presence of cariporide (P < 0.05 between groups), respectively. Although body weights were significantly lower in both monocrotaline-treated groups compared with vehicle treatment, with cariporide the net gain in body weight was twice that seen in the monocrotaline-treated animals without cariporide. Monocrotaline also increased RV NHE-1 and atrial natriuretic peptide mRNA expression, which was abrogated by cariporide. Monocrotaline-induced myocardial necrosis, fibrosis, and mononuclear infiltration was completely prevented by cariporide. Cariporide had no effect on monocrotaline-induced pulmonary intimal wall thickening. Our results demonstrate that cariporide directly attenuates myocardial dysfunction after monocrotaline administration independent of pulmonary vascular effects. NHE-1 inhibition may represent an effective adjunctive therapy that selectively targets myocardial hypertrophic responses in pulmonary vascular injury.

Cardiac myocytes exposed to anoxia-reoxygenation promote neutrophil transendothelial migration

The goal of the present study was to assess whether cardiac myocytes exposed to anoxia-reoxygenation (A/R) could generate a chemotactic gradient for polymorphonuclear neutrophil (PMN) transendothelial migration. Exposure of neonatal mouse cardiac myocytes to A/R induced an oxidant stress in the myocytes. Supernatants obtained from A/R-conditioned myocytes promoted mouse PMN migration across mouse myocardial endothelial cell monolayers. This increase in PMN transendothelial migration could be prevented if catalase or a platelet-activating factor (PAF) antagonist was added to the supernatants before assay. Supernatants from A/R-conditioned myocytes activated endothelial cells by inducing an intracellular oxidant stress. The oxidant stress and PMN transendothelial migration induced by supernatants from A/R-conditioned myocytes were substantially reduced when endothelial cells derived from manganese superoxide dismutase overexpressing mice were used in the assays. Supernatants from A/R-conditioned myocytes also increased endothelial cell surface levels of E-selectin and intercellular adhesion molecule-1. Our results indicate that cardiac myocytes exposed to A/R can generate a chemotactic gradient, presumably due to production and release of stable oxidants and PAF. The ability of supernatants from A/R-conditioned myocytes to promote PMN transendothelial migration was largely dependent on induction of an oxidant stress in endothelial cells. In addition, these supernatants also induced a proadhesive phenotype in the endothelial cells.

The ABC transporter Pdr5p mediates the efflux of nonsteroidal ecdysone agonists in Saccharomyces cerevisiae

We have previously shown that the synthetic nonsteroidal ecdysone agonist tebufenozide (RH-5992) is actively excluded by resistant cells of insects. To identify the transporter that could be involved in the efflux of RH-5992, the role of three ATP binding cassette transporters, Pdr5p, Snq2p and Ycf1p, has been studied using transporter-deletion mutants of yeast Saccharomyces cerevisiae. PDR5 (pleiotropic drug resistance 5) deletion mutants (Deltapdr5 and Deltapdr5Deltasnq2) retained significantly higher levels of 14C-radiolabeled RH-5992 within the cells when compared to wild-type strain or single deletion mutants of SNQ2 (Deltasnq2) and YCF1 (Deltaycf1). Introduction of an expression vector containing the PDR5 gene into the PDR5 single deletion mutant reversed the effect, resulting in the active exclusion of [14C]RH-5992 from these cells as efficiently as the wild-type cells. These results demonstrated that the ABC transporter Pdr5p but not Snq2p or Ycf1p was responsible for the active exclusion of [14C]RH-5992 in yeast. This exclusion was temperature-dependent and was blocked by the ATPase inhibitors oligomycin and vanadate, indicating that the efflux was an active process. The mutants with the PDR5 deletion can also selectively accumulate [14C]RH-0345 and [14C]RH-2485, but not [14C]RH-5849, indicating that these three compounds share the same transporter Pdr5p for efflux.

Vrp1p functions in both actomyosin ring-dependent and Hof1p-dependent pathways of cytokinesis

Vrp1p/verprolin/End5p is a Saccharomyces cerevisiae proline-rich protein, structurally and functionally related to human Wiskott-Aldrich syndrome protein-interacting protein. Vrp1p is required for viability at 37 degrees C, but not 24 degrees C. Here, we show that loss of Vrp1p (vrp1Delta) leads to a 3-4-fold delay in cytokinesis, wide bud necks, abnormal actomyosin rings, and aberrant septa even at 24 degrees C. Like other mutations affecting the actomyosin ring, vrp1Delta is synthetic lethal with deletion of HOF1 (or CYK2), which encodes a protein related to mammalian proline serine threonine phosphatase-interacting protein and Schizosaccharomyces pombe Cdc15p required for an actomyosin ring-independent pathway of cytokinesis in S. cerevisiae. At 37 degrees C, vrp1Delta cells rapidly cease dividing and exhibit a novel terminal phenotype: a single large bud, two well-separated nuclei, and an interphase microtubule array. The arrested cells have a persistent ring containing both actin and myosin at the bud neck. Many also exhibit some polarisation of cortical actin patches to the bud neck. Vrp1p binds an SH3-domain-containing fragment of Hof1p in vitro. Vrp1p is required in vivo for Hof1p relocalisation to a single ring at the bud neck prior to cytokinesis at 37 degrees C, but not at 24 degrees C. Vrp1p thus acts in both actomyosin ring formation and function, as well as in Hof1p localisation during cytokinesis.

A novel method for enzyme immobilization: direct encapsulation of acid phosphatase in nanoporous silica host materials

Immobilization of acid phosphatase (ACP) in mesoporous or, more generally, nanoporous silica has been accomplished via the sol-gel reactions of tetramethyl orthosilicate in the presence of ACP and of D-glucose (DG) as a nonsurfactant template, which is subsequently removed by water extraction after the formation of nanocomposite gels. Characterization of the silica host after the removal of DG shows that the pore size and volume generally increase with the DG content. At high DG contents, the silica hosts are nanoporous with interconnected nanoscaled pores/channels of regular diameter (e.g., 3.4 nm). Catalytic activity of ACP encapsulated in nanoporous hosts is significantly improved over that in microporous host prepared in the absence of DG. The apparent enzymatic activity at various pH values and substrate concentrations correlates well with the nanostructures of the host matrices. As the DG content is increased in the synthesis, the activity tends to increase. At a DG content of 42-60 wt%, the samples exhibit activities about triple that of the template-free control. These and other results from enzymatic kinetic studies suggest that the increase in the pore size and volume facilitates the transport of the substrate and product molecules in the host matrices, leading to the observed increase in activity. The thermal stability of ACP is remarkably improved upon immobilization. There is no detectable leakage of ACP from the host matrices and the biogels are reuseable. This study provides a useful protocol for the development of nanotechnology for various biocatalysts and biosensors.

Increased L-arginine uptake and inducible nitric oxide synthase activity in aortas of rats with heart failure

L-Arginine crosses the cell membrane primarily through the system y(+) transporter. The aim of this study was to investigate the role of L-arginine transport in nitric oxide (NO) production in aortas of rats with heart failure induced by myocardial infarction. Tumor necrosis factor-alpha levels in aortas of rats with heart failure were six times higher than in sham rats (P < 0.01). L-Arginine uptake was increased in aortas of rats with heart failure compared with sham rats (P < 0.01). Cationic amino acid transporter-2B and inducible (i) nitric oxide synthase (NOS) expression were increased in aortas of rats with heart failure compared with sham rats (P < 0.05). Aortic strips from rats with heart failure treated with L-arginine but not D-arginine increased NO production (P < 0.05). The effect of L-arginine on NO production was blocked by L-lysine, a basic amino acid that shares the same system y(+) transporter with L-arginine, and by the NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME). Treatment with L-lysine and L-NAME in vivo decreased plasma nitrate and nitrite levels in rats with heart failure (P < 0.05). Our data demonstrate that NO production is dependent on iNOS activity and L-arginine uptake and suggest that L-arginine transport plays an important role in enhanced NO production in heart failure.

Plasminogen activators and inhibitors are transcribed during early macaque implantation

Plasminogen activators and inhibitors may be important early in primate implantation but evidence for this is sparse in non-human primates. We define the expression of urokinase type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1) and type 2 (PAI-2), the receptor for uPA (uPAR) and fibrin/fibrinogen in monkey implantation sites. In situ hybridization and immuno-histochemical localization of rhesus monkey implantation sites (day 15-16 postovulation) indicate: (1) uPA mRNA is localized to placental trophoblast, epithelial plaque and endometrial stroma. (2) tPA mRNA is mainly expressed in glandular cells of endometrium. (3) PAI-1 expression is linked to a specific population of trophoblasts that confront maternal cells, adding support to our view that it has a regulatory role in trophoblast invasion. (4) Localization of tPA antigen confirms that uterine glands are the major source of tPA and that it is also closely associated with fibrin(ogen) suggesting its possible function during implantation is fibrinolysis. (5) Unlike uPA mRNA, however, the distribution of uPA protein and its cell surface receptor uPAR suggests that it mediates trophoblast invasion and plays a significant role in angiogenesis. (6) PAI-2, the inhibitor associated with pregnancy in humans, was found in unidentified cells located specifically along the maternofetal junction. This localization adjacent to areas of cell death at the maternofetal junction implies that it may have a role as a protective curtain with anti-apoptotic function. In conclusion our results suggest that gene expression of PAs and PAIs in early implantation sites are tissue-specific, location-sensitive and function-related.

Polarization instability of femtosecond pulse splitting in normally dispersive self-focusing media

We investigate the propagation of elliptically polarized intense femtosecond pulses through third-order media. Self-focusing and pulse splitting can be controlled by alternation of the polarization state.

Methylation of the protein phosphatase 2A catalytic subunit is essential for association of Balpha regulatory subunit but not SG2NA, striatin, or polyomavirus middle tumor antigen

Binding of different regulatory subunits and methylation of the catalytic (C) subunit carboxy-terminal leucine 309 are two important mechanisms by which protein phosphatase 2A (PP2A) can be regulated. In this study, both genetic and biochemical approaches were used to investigate regulation of regulatory subunit binding by C subunit methylation. Monoclonal antibodies selectively recognizing unmethylated C subunit were used to quantitate the methylation status of wild-type and mutant C subunits. Analysis of 13 C subunit mutants showed that both carboxy-terminal and active site residues are important for maintaining methylation in vivo. Severe impairment of methylation invariably led to a dramatic decrease in Balpha subunit binding but not of striatin, SG2NA, or polyomavirus middle tumor antigen (MT) binding. In fact, most unmethylated C subunit mutants showed enhanced binding to striatin and SG2NA. Certain carboxy-terminal mutations decreased Balpha subunit binding without greatly affecting methylation, indicating that Balpha subunit binding is not required for a high steady-state level of C subunit methylation. Demethylation of PP2A in cell lysates with recombinant PP2A methylesterase greatly decreased the amount of C subunit that could be coimmunoprecipitated via the Balpha subunit but not the amount that could be coimmunoprecipitated with Aalpha subunit or MT. When C subunit methylation levels were greatly reduced in vivo, Balpha subunits were found complexed exclusively to methylated C subunits, whereas striatin and SG2NA in the same cells bound both methylated and unmethylated C subunits. Thus, C subunit methylation is critical for assembly of PP2A heterotrimers containing Balpha subunit but not for formation of heterotrimers containing MT, striatin, or SG2NA. These findings suggest that methylation may be able to selectively regulate the association of certain regulatory subunits with the A/C heterodimer.

Developmental expression and stress induction of glutathione S-transferase in the spruce budworm, Choristoneura fumiferana

Developmental and stress-induced expression of Choristoneura fumiferana glutathione S-transferase (CfGST) mRNA and protein were examined using Northern blots and Western blots. High levels of CfGST mRNA and protein were detected in 1st instar larvae and diapausing 2nd instar larvae. Expression of CfGST gradually decreased during larval development from 3rd to 5th instar, after which the expression increased once again, reaching peak levels in 6th instar larvae. CfGST mRNA and protein were undetectable in the pupal stage. Exposure to low temperature did not induce an increase in CfGST expression. Feeding on balsam fir foliage resulted in an increase in the expression of CfGST as compared to larvae that fed on artificial diet. The bacterial insecticide, Bacillus thuringiensis delta-endotoxin (Bt), the non-steroidal ecdysone analog, tebufenozide, and the synthetic pyrethroid, permethrin, induced the expression of CfGST mRNA in 5th instar larvae, whereas the chitin synthesis inhibitor, diflubenzuron, did not have any such effect. These results suggest that CfGST plays an important role in detoxifying various allelochemicals and insecticides in the spruce budworm. The developmental expression pattern strongly suggests that in addition to detoxification, CfGST might be involved in other functions.

Human ovarian cancer and cisplatin resistance: possible role of inhibitor of apoptosis proteins

The inhibitor of apoptosis proteins (IAPs) constitutes a family of highly conserved apoptosis suppressor proteins that were originally identified in baculoviruses. Although IAP homologs have recently been demonstrated to suppress apoptosis in mammalian cells, their expression and role in human ovarian epithelial cancer and chemotherapy resistance are unknown. In the present study we used cisplatin-sensitive and -resistant human ovarian surface epithelial (hOSE) cancer cell lines and adenoviral antisense and sense complementary DNA expression to examine the role of IAP in the regulation of apoptosis in human ovarian cancer cells and chemoresistance. Antisense down-regulation of X-linked inhibitor of apoptosis protein (Xiap), but not human inhibitor of apoptosis protein-2 (Hiap-2), induced apoptosis in cisplatin-sensitive and, to a lesser extent, in -resistant cells. Cisplatin consistently decreased Xiap content and induced apoptosis in the cisplatin-sensitive, but not cisplatin-resistant, cells. Hiap-2 expression was either unaffected or inhibited to a lesser extent. The inhibition of IAP protein expression and induction of apoptosis by cisplatin was time and concentration dependent. Infection of cisplatin-sensitive cells with adenoviral sense Xiap complementary DNA resulted in overexpression of Xiap and markedly attenuated the ability of cisplatin to induce apoptosis. Immunohistochemical localization of the IAPs in hOSE tumors demonstrated the presence of Xiap and Hiap-2, with their levels being highest in proliferative, but not apoptotic, epithelial cells. These studies indicate that Xiap is an important element in the control of ovarian tumor growth and may be a point of regulation for cisplatin in the induction of apoptosis. These results suggest that the ability of cisplatin to down-regulate Xiap content may be an important determinant of chemosensitivity in hOSE cancer.

Studies on metal phthalocyanine as a dual functional mimic enzyme

Four phthalocyanines (iron tetracarboxylphthalocyanine, copper tetracarboxylphthalocyanine, manganese tetracarboxylphthalocyanine, cobalt tetracarboxylphthalocyanine) were used as dual functional mimic enzymes of superoxide dismutase (SOD) and catalase (CAT). The first function, eliminating O2-, was proved by using riboflavine-methionine photoreduction method in the concentration range of 10(-5) to 10(-6) mol/L. The second function, clearing out H2O2, was demonstrated by means of spectrophotometry with the decomposing percentage being increased with the increase of the concentration of the imitating compounds. Measurements of metal phthalocyanines, SOD and CAT by the liver homogenate technique of mice showed that they had obvious action of decreasing the lipid peroxidation.

Long-term effects of cis and trans monounsaturated (18:1) and saturated (16:0) fatty acids on the synthesis and secretion of apolipoprotein A-I- and apolipoprotein B-containing lipoproteins in HepG2 cells

The objective of this study was to compare the long-term effects of oleic (cis 18:1), elaidic (trans 18:1), and palmitic (16:0) acids on hepatic lipoprotein production, using HepG2 cells as an experimental model. The net accumulation in the medium of apolipoprotein A-I (apoA-I) was not significantly altered by fatty acids, whereas that of apoB was increased with oleic and elaidic acids. Oleic acid, and to a lesser extent elaidic and palmitic acids, increased the mass of triglycerides in the medium and the incorporation of [(3)H]glycerol into secreted triglycerides. The incorporation of [(14)C]acetate into cellular and secreted total cholesterol was stimulated by 96% and 83%, respectively, with elaidic acid but was not significantly modified by oleic or palmitic acid. Relative to oleic acid, the secretion of (14)C-labeled phospholipids and triglycerides was decreased 28% to 31% with elaidic and palmitic acids whereas that of free cholesterol and cholesteryl esters was enhanced 93% and 73%, respectively, with elaidic acid but remained unchanged with palmitic acid. Compared with oleic acid, elaidic acid stimulated the secretion of very low density lipoprotein cholesterol (VLDL-Chol), low density lipoprotein cholesterol (LDL-Chol), and high density lipoprotein cholesterol (HDL-Chol) by 43%, 70%, and 34%, respectively, whereas palmitic acid decreased VLDL-Chol but had no significant effect on LDL-Chol and HDL-Chol. The ratios of total cholesterol to HDL-Chol were 3.17, 3.60, and 3.25 with oleic, elaidic, and palmitic acids, respectively; the corresponding ratios of LDL-Chol to HDL-Chol were 0.87, 1.10, and 0.93, respectively. Compared with oleic and palmitic acids, the LDL and HDL particles secreted in the presence of elaidic acid contained higher levels of free cholesterol and cholesteryl esters and a lower content of phospholipids. The phospholipid-to-total cholesterol ratios of HDL were 1.05, 0.40, and 0.76 with oleic, elaidic, and palmitic acids, respectively. Our results indicate that in comparison with cis monounsaturated and saturated fatty acids, trans fatty acids have more adverse effects on the concentration and composition of lipoproteins secreted by HepG2 cells.

[Clinical significance of beta-hCG and human placental lactogen in serum of normal pregnancies and patients with pregnancy induced hypertension]

OBJECTIVE

To examine the level of beta-hCG and Human Placental Lactogen (HPL) in maternal serum of normal pregnancies and patients with pregnancy induced hypertension (PIH) and to study the clinical significance and effects of them on the pathogenesis of the disease.

METHODS

Serum levels of beta-hCG and HPL of 142 normal pregnant women and 43 patients with PIH (16 mild, 12 moderate and 15 severe) were determined by radioimmunossay.

RESULTS

(1) Serum levels of beta-hCG in all PIH subgroups [(25.33 +/- 17.80) micrograms/L in mild, (33.12 +/- 4.91) micrograms/L in moderate, (42.19 +/- 17.47) micrograms/L in severe] were significantly higher than the normal pregnant group [(12.33 +/- 7.92) micrograms/L; P < 0.001]. There is positive correlation between levels of beta-hCG and degrees of PIH (r = 0.677, P < 0.05). (2) Serum levels of HPL in all PIH subgroups [(14.73 +/- 3.26) mg/L in mild, (11.44 +/- 4.02) mg/L in moderate, (12.73 +/- 4.18) mg/L in severe] did not show significant difference when compared with that of normal pregnant group [(12.78 +/- 4.67) mg/L; P > 0.05]. Furthermore, there was no correlation between levels of HPL and degrees of PIH (r = -0.300, P > 0.05).

CONCLUSIONS

Serum beta-hCG could reflect the degree of functional imbalance of the placental trophoblasts on PIH and it may be used as a clinical detecting index of PIH. On the other hand, HPL is not such a useful factor.

A Saccharomyces gene family involved in invasive growth, cell-cell adhesion, and mating

The cell wall of bakers' yeast contains a family of glycosyl-phosphatidylinositol (GPI)-linked glycoproteins of domain structure similar to the adhesins of pathogenic fungi. In wild-type cells each of these proteins has a unique function in different developmental processes (mating, invasive growth, cell-cell adhesion, or filamentation). What unifies these developmental events is adhesion, either to an inert substrate or to a cell. Although they differ in their specificities, many of these proteins can substitute for each other when overexpressed. For example, Flo11p is required during vegetative growth for haploid invasion and diploid filamentation, whereas Fig2p is required for mating. When overexpressed, Flo11p and Fig2p can function in mating, invasion, filamentation, and flocculation. The ability of Flo11p to supply Fig2p function in mating depends on its intracellular localization to the mating projection, where Fig2p normally functions in the adhesion of mating cells. Our data show that even distant family members retain the ability to carry out disparate functions if localized and expressed appropriately.

[A randomized clinical trial of postoperative radiotherapy of the patients with non-small cell lung cancer after radical surgery]

BACKGROUND

To study the value of postoperative radiotherapy of non-small cell lung cancer (NSCLC) with lymph node metastasis (N1 to N2) after radical surgery.

METHODS

From February，1982 to December，1995,three hundred and sixty-six patients with NSCLC with N1 or N2 disease were randomized into postoperative radiation group (S+R) and surgery alone group (S alone).Radiation fields covered the ipsilateral hilum and most part of mediastinum.The mid-plane dose was 60Gy/30fx for 6 weeks.One hundred and thirty-four patients in S+R and 162 patients in S alone were available for analysis.Clinical data of the two groups were comparable in both arms,except for the numbers of patient with N2 disease.

RESULTS

The overall 5-year survival rates of S+R group and S alone group were 43.4%±5.1% and 40.5%±4.6%(P=0.56) respectively.The 5-year disease-free survival rates were 42.9%±5.2% in S+R and 38.3%±4.5% in S alone (P=0.28) respectively.The overall 5-year survival rate and 5-year disease-free survival rate of patients with T3-4N1M0 disease were 58.1%±15.5% and 65%±12% in S+R group,and 39.9%±10.2%(P=0.092) and 40%±10%(P=0.057) in S alone.There was less loco-regional recurrence in S+R than in S alone (P<0.01).Distant metastasis was similar in the two groups.

CONCLUSIONS

Postoperative radiation has a significant impact in decreasing local relapse,but not in overall survival.However,it may be benefit to those patients with advanced local diseases (T3-4) and early N disease (N1).

[A comparative study on the expressions of IL-4, IFN-gamma and TNF-alpha in BMMNC of acute and chronic aplastic anemia patients]

OBJECTIVE

To detect the induced levels of IL-4, IFN-gamma and TNF-alpha in the supernatant of bone marrow mononuclear cells (BMMNC) and compare the difference of immune status between acute (SAA) and chronic (CAA) aplastic anemia patients.

METHODS

Concentrations of IL-4, IFN-gamma and TNF-alpha in PHA-P-induced BMMNC supernatants were determined by ELISA assay in 11 SAA and 13 CAA patients as well as 16 controls. Concentration differences between the two groups were compared.

RESULTS

(1) The IFN-gamma and TNF-alpha levels in AA patients studied were much higher than that in controls, and IL-4 levels were normal in SAA group but elevated in CAA group. (2) TNF-alpha levels were comparable between the two AA groups, but both IL-4 and IFN-gamma levels were significantly different between them.

CONCLUSION

Enhanced cellular immunity seems to play an important role in the pathogenesis of SAA, and enhancement of both cellular and humoral immunity might contribute to the pathogenesis of CAA.

[Ligand of platelet and T cell activation antigen 1 (PTA1) expressed on Colo205 cell surface]

OBJECTIVE

To confirm the existence of PTA1 ligand (PTA1L).

METHODS

PTA1/Ig fusion protein was prepared by gene recombination and expression in COS-7 cells by DEAE-dextran transfection. The fusion protein was used as a probe in the investigation of PTA1L by immunohistochemical staining. Existence of PTA1L was further identified by adhesion experiment.

RESULTS

Colo205 cells could be stained by PTA1/Ig fusion protein specifically but not by hIg, and the adhesion of activated Jurkat cells with Colo205 could be blocked by PTA1/Ig and PTA1 mAb.

CONCLUSION

PTA1 ligand is present on the surface of Colo205 cells. These results provide a solid basis for further investigation of the role of PTA1-PTA1L interaction in the pathogenesis of neoplasm.

Molecular cloning of a female-specific cDNA with unique repeat sequences from the fat body of the adult locust, Locusta migratoria

A cDNA clone encoding a 25-kDa protein (25K) was isolated from a cDNA library made from RNA isolated from the adult fat body and ovaries of the locust, Locusta migratoria. The longest open reading frame of this cDNA clone encodes a 225-amino acid polypeptide, the N-terminal end of which was similar to the 21-kDa and 19-kDa juvenile hormone induced proteins identified in the locust hemolymph, but the C-terminal end was different. The C-terminal end of the 25K cDNA contained seven unique repeat elements of 10 amino acids each, most of which are polar residues. Expression of the 25K mRNA was tissue-, development- and sex-specific. A 1.2-kb mRNA was detected using the 25K cDNA as a probe only in the fat body of adult females. The mRNA started to appear at day 4 after the insect molted to the adult and rapidly increased by day 6. The mRNA was absent in the ovarian follicle cells and fat body of adult males. In vitro transcription and translation of the 25K cDNA produced a protein that migrated around 32 kDa on sodium dodecyl sulfate polyacrylamide gels. The 25K cDNA was expressed in a baculovirus expression system and the protein produced also migrated around 32 kDa.

[Studies on metal porphyrins as two-functional mimic of enzyme]

In this study, four metal porphyrins (tetraphenylporphyrinesulfonatoiron, tetraphenylporphyrinesulfon-atocopper, tetraphenylporphyrinesulfonatomanganese, and tetraphenyl porrphyrinesulfonatocobalt) were used as dual function mimicry of superoxide dismutase (SOD) and catalase (CAT). The first function, scavenging O2.-, has been proved by using riboflavine-methionine photoreduction method in the concentration range of 10(-5)-10(-6) mol/L. The second function, scavenging H2O2, has been demonstrated by means of spectrophotometry, and the percentage of decomposing H2O2 increases with the concentration of the imitating compounds. Metal porphyrins, SOD and CAT were measured by the liver homogenate technique of mice and the results showed that they had obvious action of decreasing the lipid peroxidation. Tetraphenylporphyrinesulfonatomanganese was measured by isolated ischemia reperfusion heart of rats. The results indicated that the Mn-TPPS4 could reduce the damages of active oxygen and had evidently protective effects on isolated ischemia-reperfusion mocardium of rats.

Expression of urokinase, plasminogen activator inhibitors and urokinase receptor in pregnant rhesus monkey uterus during early placentation

We have investigated plasmin mediated proteolysis associated with trophoblast invasion during early stages of pregnancy in the rhesus monkey. In situ hybridization and immunocytochemical localization were used to define the cellular and tissue distribution of urokinase plasminogen activator (uPA), plasminogen activator inhibitor type 1 (PAI-1) and 2 (PAI-2) and urokinase receptor in early monkey placenta and uterus. Our results indicate: (1) uPA is expressed in proliferating and invasive cytotrophoblast located in chorionic villi as well as in extravillous trophoblast associated with uterine arterioles. This raises the possibility that urokinase may play an important role in trophoblast invasion. (2) PAI-1 mRNA is specifically localized in two areas where invasive trophoblast cells encounter maternal tissue directly. The extravillous cytotrophoblast cells at the maternofetal junction express PAI-1 mRNA. The invasive endovascular trophoblast cells within the uterine arterioles also express PAI-1 mRNA. The location sensitive expression of PAI-1 mRNA at the maternofetal junction may imply a protective function of this protease inhibitor that might be induced through interaction with decidual cells. (3) Urokinase receptor antigen has also been found at the maternofetal junction and in endovascular trophoblast cells of the invaded maternal blood vessel. (4) PAI-2 immunoreactivity is found in association with cytotrophoblast cells in anchoring choronic villi suggesting its association with early placentation. In conclusion, we propose that the plasmin/plasminogen activator system may not only regulate extracellular matrix degradation, but also modify migration and invasive behaviour of extravillous trophoblast cells, during early placentation.

[Studies on the effect-increasing components for molluscacides in nut of Areca catech L]

OBJECTIVE

To investigate the effect-increasing action of Areca catech for molluscacide.

METHOD

Experiments were conducted on the effect-increasing components isolated from the dry nut of A. catech.

RESULT

Arecoline has been proved the most effect-increasing component.

CONCLUSION

When used with SPA arecoline could reduce markedly the doses of the two agents.

Venous neuropeptide Y receptor responsiveness in patients with chronic heart failure

BACKGROUND

Chronic heart failure is associated with increased sympathetic nerve activity and elevated plasma neuropeptide Y levels. The aim of this study was to investigate whether increased neuropeptide Y release altered vascular neuropeptide Y responses in the dorsal hand veins in patients with chronic heart failure.

METHODS AND RESULTS

Neuropeptide Y responsiveness was studied in vivo with use of a hand vein tonometry technique in 14 patients with chronic heart failure and left ventricular ejection fraction (LVEF) values <20%, 16 patients with LVEF values from 20% to 35%, and 16 age-similar healthy control subjects. Plasma norepinephrine and neuropeptide Y levels were significantly elevated in patients with chronic heart failure and LVEF values <20% compared with control subjects (P < .01). Plasma neuropeptide Y but not norepinephrine levels were significantly elevated in patients with chronic heart failure and LVEF values from 20% to 35% compared with control subjects (P < .01). Increasing doses of neuropeptide Y (25 to 2,000 pmol/min) were infused into a dorsal hand vein of each subject. Dose-dependent venoconstriction to neuropeptide Y was observed in all subjects studied. The neuropeptide Y dose-response curve in patients with LVEF values from 20% to 35% was significantly shifted to the left compared with patients with LVEF values <20% and control subjects (P < .01), whereas no significant difference was observed between the control subjects and the patients with LVEF values <20%. No significant difference in neuropeptide Y dose responses was observed between patients with chronic heart failure with plasma neuropeptide Y levels above the median and patients with chronic heart failure with plasma neuropeptide Y levels below the median.

CONCLUSIONS

In vivo venous neuropeptide Y receptor responsiveness is increased in patients with chronic heart failure and LVEF values from 20% to 35%. This increased neuropeptide Y responsiveness may contribute to venoconstriction at this stage of heart failure.

[Study on the in vitro cleavage abilities of ribozymes specific to different sites of bcr-abl fusion gene and their induction of apoptosis in K562 cells]

OBJECTIVE

To investigate the in vitro cleavage abilities of ribozymes specific to different sites of bcr-abl fusion gene and their effects on K562 cell.

METHODS

First, three single-ribozymes specific to the fusion point were designed. After recombination, 6 vectors including single-, double- and triple- ribozymes were constructed and their in vitro cleavage abilities were compared. Then the triple-unit ribozyme retroviral vector was transfected into K562 cell to test its effect on cell cycle, apoptosis and cell structure.

RESULTS

These ribozymes can cleave the template in vitro with different efficiency. The triple-unit ribozyme, with an efficiency of 70.8%, was the most efficient one. The cleavage efficiency of single-unit RZ1, RZ2 and RZ3 was 54.6%, 25.3% and 3.6%, respectively. Those of double-unit RZ12 and RZ23 were 60.7% and 30.3% respectively. The triple-unit ribozyme could inhibit the K562 cell growth by inducing apoptosis.

CONCLUSION

It is a new way to treat CML by ribozymes specific to bcr-abl fusion gene, which made it available to purge bone marrow by bcr-abl specific ribozymes.

Tumor necrosis factor-alpha induces apoptosis via inducible nitric oxide synthase in neonatal mouse cardiomyocytes

OBJECTIVE

It has been demonstrated that tumor necrosis factor-alpha (TNF alpha) induces apoptosis in cardiac myocytes. However, its mechanism of action is still not well understood. In the present study, we hypothesized that TNF alpha induces myocardial apoptosis by induction of inducible nitric oxide synthase (iNOS).

METHODS

Neonatal cardiac myocytes were isolated from iNOS (-/-) mutant and C57BL6 wild type mice. Cells were cultured for 3 days before treatment with an NO donor or TNF alpha. Following treatment with S-nitroso-N-acetyl-penicillamine (SNAP) or TNF-alpha, cells were tested for apoptosis by terminal deoxynucleotidyl transfer-mediated end labeling (TUNEL) staining and cell death detection ELISA. NO production was measured by nitrite concentration in the culture medium. Cardiomyocyte expression of iNOS and TNF type 1 receptor (TNFR1) mRNA was determined by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

SNAP (0.01-100 microM) induced apoptosis of cardiac myocytes in a concentration-dependent manner in the wild type mice (n = 5, P < 0.01). TNFR1 mRNA was expressed in neonatal cardiomyocytes from both wild type and iNOS (-/-) mutant mice. TNF alpha induced a concentration-dependent increase in iNOS mRNA expression and nitrite production as well as significant apoptosis of cardiomyocytes in the wild type mice (n = 4, P < 0.01). However, without iNOS expression, the apoptotic effects of TNF-alpha were significantly attenuated in cardiomyocytes from iNOS (-/-) mutant mice (n = 4, P < 0.05).

CONCLUSION

TNF alpha induces apoptosis via iNOS expression and NO production in neonatal mouse cardiomyocytes.

[Construction and expression of HLA-DRalpha, DRB1*0401 transgenic mice model]

OBJECTIVE

To construct transgenic mice model on DR alpha and DRB1*0401 of human MHC-II molecules.

METHODS

By microinjection techniques on germ nucleus of zygotes, DRalpha and DRB1*0401 genes were injected into zygotes of C57BL/6 x DBA/1 hybrid mice and transplanted into the oviducts of pseudopregnancy female mice. The integration and expression of exogenous genes in offspring were detected by PCR, Southern blot and Northern blot, RT-PCR analysis.

RESULTS

There were 5 founders of all injected mice, which had steadily inherited to the fifth generation. It was found that 95 mice were positive by PCR and 68 mice were integrated exogenous gene by Southern blot analysis. DRalpha and DRB1*0401 genes were expressed on spleen and kidney of transgenic mice.

CONCLUSION

This experiment on the construction of DRalpha and DRB1*0401 transgenic mice model is a success.

[Studies on the increasing-effect components for molluscicides in nut of Areca catech]

The increasing-effect components for molluscicides isolated from the dry nut of Areca catech L. were studied. The results showed that arecoline was the most effective and it could decrease remarkably the amount of drugs i.e. saponium of Phytolacca acinosa, SPA, and sodium pentachloro phenate, NaPCP, when used together.

Ras signaling is required for serum-induced hyphal differentiation in Candida albicans

Serum induces Candida albicans to make a rapid morphological change from the yeast cell form to hyphae. Contrary to the previous reports, we found that serum albumin does not play a critical role in this morphological change. Instead, a filtrate (molecular mass, <1 kDa) devoid of serum albumin induces hyphae. To study genes controlling this response, we have isolated the RAS1 gene from C. albicans by complementation. The Candida Ras1 protein, like Ras1 and Ras2 of Saccharomyces cerevisiae, has a long C-terminal extension. Although RAS1 appears to be the only RAS gene present in the C. albicans genome, strains homozygous for a deletion of RAS1 (ras1-2/ras1-3) are viable. The Candida ras1-2/ras1-3 mutant fails to form germ tubes and hyphae in response to serum or to a serum filtrate but does form pseudohyphae. Moreover, strains expressing the dominant active RAS1(V13) allele manifest enhanced hyphal growth, whereas those expressing a dominant negative RAS1(A16) allele show reduced hyphal growth. These data show that low-molecular-weight molecules in serum induce hyphal differentiation in C. albicans through a Ras-mediated signal transduction pathway.

Decreased responsiveness of vascular postjunctional alpha1-, alpha2-adrenoceptors and neuropeptide Y1 receptors in rats with heart failure

Heart failure is associated with increased sympathetic nerve activity. We hypothesized that chronic sympathetic stimulation in heart failure resulted in decreased vascular sympathetic responsiveness. A pithed rat model was employed to evaluate peripheral vascular alpha-adrenoceptor and neuropeptide Y (NPY) receptor responsiveness. Heart failure was induced in Sprague-Dawley rats by coronary artery ligation. Sham operated rats (Sham) served as controls. Two months after this surgical procedure, both heart failure (n = 30) and Sham (n = 30) rats underwent standard pithing procedure. Pressor responses to preganglionic sympathetic nerve stimulation (PNS) and activation of postjunctional alpha1- and alpha2-adrenoceptors as well as Y1 receptors were studied. In response to PNS, cardiac index was similar between heart failure and sham rats (P = n.s.). Mean arterial pressure (MAP) increased in a frequency-dependent fashion after PNS in heart failure rats as well as in control rats. All the agonists used, i.e. the alpha1-adrenoceptor agonist phenylephrine, the alpha2-adrenoceptor agonists clonidine and BHT933 as well as NPY, induced dose-dependent increases in MAP in heart failure and in sham rats. However, in rats with heart failure, the response to all the agonists studied was significantly decreased and the dose response curves were shifted to the right (P < 0.01). We conclude that in vivo vascular response to postjunctional alpha1- and alpha2-adrenoceptors as well as Y1 receptors are decreased in rats with heart failure.

Effects of L-arginine on endothelial and cardiac function in rats with heart failure

We examined the effects of chronic oral L-arginine treatment on endothelial and cardiovascular function in rats with heart failure induced by coronary artery ligation. Both heart failure and sham-operated rats were treated with either L-arginine in drinking water (12.5 or 50 g/l) or water placebo for 8 weeks following surgery. Plasma L-arginine levels in heart failure rats (153 +/- 11 microM) were lower than sham rats (201 +/- 13 microM, P < 0.05). The lower dose L-arginine treatment improved endothelium-dependent relaxation of isolated aortic rings of heart failure rats, while the higher dose of L-arginine treatment did not. Neither low nor high dose of L-arginine treatment improved hemodynamic parameters in heart failure rats. Thus, chronic oral L-arginine treatment at a dose of 12.5 g/l in drinking water improves endothelium-dependent relaxation, but fails to improve in vivo cardiac function in rats with heart failure.

Expression of tissue type and urokinase type plasminogen activators as well as plasminogen activator inhibitor type-1 and type-2 in human and rhesus monkey placenta

The distribution of mRNAs and antigens of tissue type (t) and urokinase type (u) plasminogen activators (PA) plus their corresponding inhibitors, type-1 (PAI-1) and type-2 (PAI-2) were studied in human and rhesus monkey placentae by in situ hybridisation and immunocytochemistry. Specific monkey cRNA and antibodies against human tPA, uPA, PAI-1 and PAI-2 were used as probes. The following results were obtained. (1) All the molecules tPA, uPA, PAI-1 and PAI-2 and their mRNAs were identified in the majority of the extravillous cytotrophoblast cells of the decidual layer between Rohr's and Nitabuch's striae and in cytotrophoblast cells of the chorionic plate, basal plate, intercotyledonary septae and cytotrophoblast cells of the chorionic villous tree. (2) Expression of uPA and PAI-2 was noted in villous trophoblast whereas tPA and PAI-1 were mainly concentrated where detachment from maternal tissue occurs. (3) No expression of tPA, uPA, PAI-1 and PAI-2 was observed in the basal plate endometrial stromal cells, chorionic plate connective tissue cells, septal endometrial stromal cells or villous core mesenchyme. (4) The distribution of probes observed following in situ hybridisation is generally consistent with the immunofluorescence pattern of the corresponding antigens and no significant interspecies differences were noted. It is possible that both decidual and extravillous trophoblast cells of placentae of human and rhesus monkey are capable of producing tPA, uPA, PAI-1 and PAI-2 to differing extents. Coordinated expression of these genes in the tissue may play an essential role in the maintenance of normal placentation and parturition. The differences in distribution we observed are consistent with the suggestion that coordinated expression of tPA and its inhibitor PAI-1 may play a key role in fibrinolytic activity in the early stages of placentation and separation of placenta from maternal tissue at term. On the other hand, uPA with its inhibitor PAI-2 appears mainly to play a role in degradation of trophoblast cell-associated extracellular matrix, and thus may be of greatest importance during early stages of placentation.

Expression of the steroidogenic acute regulatory protein and luteinizing hormone receptor and their regulation by tumor necrosis factor alpha in rat corpora lutea

Expression of both mRNA and protein of the steroidogenic acute regulatory protein (StAR), in correlation with progesterone (P) production and LH receptor (LHR) mRNA expression, was studied in the corpora lutea (CL) of gonadotropin-induced-pseudopregnant and pregnant rats at various stages of CL development. Immature female rats, 21-22 days old, were injected s.c. with 20 IU eCG to stimulate follicle growth and then with 20 IU hCG 48 h later to induce ovulation. The ovaries were removed at various stages of CL development; either CL were isolated and snap frozen for total RNA analysis, or whole ovaries were fixed in Bouin's fluid for paraffin sectioning. The results of in situ hybridization, immunohistochemistry, and Northern blotting showed that the increase in StAR mRNA and protein expression was well correlated with the increase in serum P concentration. StAR expression was restricted to the luteal cells or theca cells in antral follicles. Both StAR mRNA and protein in the CL of pseudopregnant rats increased steadily on Day 1 and Day 4, reached highest levels on Day 4, and then dropped sharply on Day 8 when luteolysis takes place. LHR mRNA content was high on Day 1 but dropped significantly on Day 2. LHR mRNA increased to high levels on Day 4 and 8 and then declined on Day 12. StAR mRNA and protein levels in the CL of pregnant rats were high during early luteal development (Day 2, 4), increased even further on Day 9, and decreased on Day 13 when luteolysis takes place. It is therefore suggested that the expression of StAR coincides well with the capacity of P production in the CL and that StAR expression can be used as a functional "marker" of CL development. To study the possible effect of cytokines on StAR expression, pseudopregnant rats on Day 5 were injected s.c. with 10 IU hCG plus 20 microg prolactin (PRL), with or without 500 IU tumor necrosis factor alpha (TNFalpha) 30 min later. TNFalpha significantly inhibited hCG/PRL-induced StAR and LHR mRNA expression at 1 and 3 h post-TNFalpha. It is suggested that the luteolytic effect of TNFalpha may be mediated by its direct inhibition on StAR expression or by an indirect decrease in LHR expression.

Orally administered NHE1 inhibitor cariporide reduces acute responses to coronary occlusion and reperfusion

Na+/H+ exchange (NHE) mediates myocardial ischemic and reperfusion injury. We examined the effects of dietary administration of the potent and selective NHE1 inhibitor cariporide on acute responses to coronary artery ligation and reperfusion in the anesthetized rat. Male Sprague-Dawley rats received control rat chow or an identical diet containing 3 parts per million of cariporide for 1 wk before 225 min of occlusion of the left main coronary artery or 45 min of occlusion followed by 180 min of reperfusion. Hearts were excised and divided into left ventricle, right ventricle, and interventricular septum for analysis of NHE1 mRNA expression and apoptosis by staining with terminal deoxynucleotidyl transferase-mediated nick end labeling. Ischemia and reperfusion were associated with a threefold elevation in NHE1 mRNA expression in control animals that was significantly reduced in cariporide-fed rats. Cariporide reduced mortality from 26% of animals to 0%. The incidence of all arrhythmias was significantly reduced, including ventricular fibrillation (from 42 to 0%) and ventricular tachycardia (from 81 to 15%), as well as the number of ventricular premature beats (from 70 +/- 12 to 17 +/- 6). Cariporide moderately reduced apoptosis only in the reperfused left ventricle to values not significantly greater than those in sham-operated animals, and this was associated with a significantly higher ratio of Bcl-2 to Bax. This study suggests that NHE inhibition with dietary cariporide represents an effective management of acute postinfarction responses.

[Study of the physiological characteristics of a strain which can change the color of red lead on Dunhuang mural]

A strain which was isolated from Dunhuang Murual was investigated. It belongs to Flavobacterium. In media added in Pb3O4, colonies show brown and black. After identified pigments, it showed that the brown was caused by the oxidation of Pb3 O4 into PbO2 by the strain. The optimal oxidative condition is at pH 9.8, 37 degrees C and dark environment. The genes for oxidation is on plasmid and the oxidation was inhibited under pure O2 and N2 conditions, too 5 x 10(-3) mol/ml NaN3 is enough. The strain was able to absorb lead initiative. The transmission electron microscope showed that lead locate in protoplasts.

[Studies on microbial factor on color change of Dunhuang mural. III. Effect of Cladosporium sp. on color-change of red lead in the surface of mural]

The conditions isolated Cladosporium sp. from Mural of Dunhuang grottoe germinated on the surface of imitated mural were as follows: 20 degrees C RH 60% or 30 degrees C RH 50%, which could be reached occasionally in some grottoes. Bone glue had protective function on red lead, while Cladosporium sp. could decompose bone glue and form some metabolite (such as oxalic acid, etc) as it grows. Then it could form a special chemical circumstance, which promoted the change from red lead to while lead.

Enhanced in vivo alpha1- and alpha2-adrenoceptor-mediated venoconstriction with indomethacin in humans

Vasodilator prostaglandins are released in vitro from endothelium during adrenergic stimulation. We hypothesized that indomethacin would block this production in vivo and increase venoconstriction to alpha1- and alpha2-stimulation but not to the nonadrenergic agonist PGF2alpha. Hand vein distension was measured in 24 normal subjects (23.0 +/- 0.5 yr) during local infusions of phenylephrine (8-12,000 ng/min), clonidine (3-7,000 ng/min), or PGF2alpha (1-2,048 ng/min) plus indomethacin (3 microg/min) versus saline on two separate days. Dose-dependent venoconstriction to phenylephrine occurred in all subjects, with a parallel shift to the left with indomethacin (P = 0. 003) and a decrease in the phenylephrine 50% effective dose (1,009 vs. 241 ng/min, geometric means, P = 0.012). Venoconstriction to clonidine was more variable, with most subjects eliciting a biphasic response (initial venoconstriction followed by attenuation). With indomethacin, the dose-response curve was displaced up and to the left (P = 0.005), and peak venoconstriction was increased (51.1 +/- 6.8 vs. 27.2 +/- 5.3% of control, P = 0.018) without a biphasic response. In all subjects, PGF2alpha elicited dose-dependent venoconstriction that was not altered by indomethacin. Thus venous alpha1- and alpha2-stimulation results in release of vasodilator prostaglandins that antagonize the venoconstrictor response. This modulates the sympathetic response of venous smooth muscle and may be important in diseases with endothelial dysfunction.

Overexpression of protein kinase C alpha enhances lipopolysaccharide-induced nitric oxide formation in vascular smooth muscle cells

Our previous studies showed that lipopolysaccharide (LPS)-induced nitric oxide (NO) synthesis in cardiovascular tissues is attenuated by protein kinase C (PKC) inhibitors. In the current study, we identify a specific PKC isotype involved in the LPS signal transduction pathway that leads to NO formation in rat vascular smooth muscle cells (VSMC). VSMC were transfected with a mammalian expression vector containing a full length PKCalpha cDNA insert, and a stable transfectant overexpressing PKCalpha was obtained as evidenced by increased expression of PKCalpha mRNA and protein. In response to 100 ng/ml LPS stimulation, the PKCalpha transfectants showed a 1.8-fold increase in PKC activity at 30 min and a twofold increase in NO production over 24 hr compared with cells transfected with control plasmids. The LPS-stimulated increase in NO synthesis in PKCalpha transfectants was blocked by the specific PKCalpha inhibitor Gö 6976. After 6 hr LPS treatment, PKCalpha-transfected and control cells showed equivalent increases in mRNA and protein for the inducible NO synthase. NO synthase activity of the cell extracts assayed in the presence of excess substrate and cofactors was not significantly different between PKCalpha-transfected and control cells after LPS stimulation. However, mRNA levels for GTP cyclohydrolase I, a key enzyme in (6R)-tetrahydro-L-biopterin synthesis, and cationic amino acid transporter-2, involved in L-arginine transport, was enhanced in cells overexpressing PKCalpha compared with control cells. These results suggest that PKCalpha plays an important role in LPS-induced NO formation and that a significant portion of this effect may be by means of enhanced substrate availability to the inducible nitric oxide synthase enzyme.

Predictive action in infancy: tracking and reaching for moving objects

Because action plans must anticipate the states of the world which will be obtained when the actions take place, effective actions depend on predictions. The present experiments begin to explore the principles underlying early-developing predictions of object motion, by focusing on 6-month-old infants' head tracking and reaching for moving objects. Infants were presented with an object that moved into reaching space on four trajectories: two linear trajectories that intersected at the center of a display and two trajectories containing a sudden turn at the point of intersection. In two studies, infants' tracking and reaching provided evidence for an extrapolation of the object motion on linear paths, in accord with the principle of inertia. This tendency was remarkably resistant to counter-evidence, for it was observed even after repeated presentations of an object that violated the principle of inertia by spontaneously stopping and then moving in a new direction. In contrast to the present findings, infants fail to extrapolate linear object motion in preferential looking experiments, suggesting that early-developing knowledge of object motion, like mature knowledge, is embedded in multiple systems of representation.

[Studies on microbiological factor in colour change of mogao graffito's mural. II. Effect of microorganism on the pigment of imitative mural]

Throung the assay and analysis of the imitative mural after cultivated with microorganisms, it has been shown that microorganisms had a pronounced effect on the pigments of the mural: the pigments secreted by microorganisms changed the colour of the mural, and produced much oxalic acid salt, which damaged the formation of crystals of the pigment, moreover, the chemical combination valence of Pb3O4 had been changed due to the metabolic products of microorganisms, that may play an important role in the chemical change of Pb3O4.

Retrotransposon R1Bm endonuclease cleaves the target sequence

The R1Bm element, found in the silkworm Bombyx mori, is a member of a group of widely distributed retrotransposons that lack long terminal repeats. Some of these elements are highly sequence-specific and others, like the human L1 sequence, are less so. The majority of R1Bm elements are associated with ribosomal DNA (rDNA). R1Bm inserts into 28S rDNA at a specific sequence; after insertion it is flanked by a specific 14-bp target site duplication of the 28S rDNA. The basis for this sequence specificity is unknown. We show that R1Bm encodes an enzyme related to the endonuclease found in the human L1 retrotransposon and also to the apurinic/apyrimidinic endonucleases. We expressed and purified the enzyme from bacteria and showed that it cleaves in vitro precisely at the positions in rDNA corresponding to the boundaries of the 14-bp target site duplication. We conclude that the function of the retrotransposon endonucleases is to define and cleave target site DNA.