A comparative study on interrelations among microelements, infection of Ureaplasma urealyticum, and male infertility

This study investigated the association among male infertility, infection of Ureaplasma urealyticum (Uu), and microelements in semen fluid. Semen analysis and cultivation of Uu are carried out to 165 samples of semen fluid. Then the contents of microelements, such as Cu, Fe, Se, Cd, Mn, and Zn, in the samples are measured respectively by an Inductively Coupled Plasma Quantometer (ICP). The contents of Fe, Se, and Zn in seminal plasma of the normal spermatic quality group are obviously higher than those of the poor spermatic quality group (p<.05), while the content of Cd in seminal plasma of the normal spermatic quality group is obviously lower than that of the poor spermatic quality group (p<.05), and the contents of Cu and Mn show no difference. The contents of Zn, Se, and Cu in seminal plasma infected with Uu are markedly lower than those of seminal plasma not infected with Uu (p<.05), while the content of Cd in seminal plasma infected with Uu is obviously higher than that in samples not infected with Uu, and the contents of Fe and Mn show no statistic difference. The contents of Zn and Se in seminal plasma of the poor spermatic qualitative semen that were infected with Uu are obviously lower than those of seminal plasma not infected with Uu (p<.05), while the content of Cd in seminal plasma of the poor spermatic qualitative semen with Uu infection is markedly higher than that of the normal seminal plasma (p<.05). Uu infection leads to the decrease of the contents of Zn and Se in semen fluid, and therefore causes spermatic quality decline. Lack of Fe or overdose of Cd may also contribute to spermatic quality decline.

Knee surgery assistance: patient model construction, motion simulation, and biomechanical visualization

We present a new system that integrates computer graphics, physics-based modeling, and interactive visualization to assist knee study and surgical operation. First, we discuss generating patient-specific three-dimensional (3-D) knee models from patient's magnetic resonant images (MRIs). The 3-D model is obtained by deforming a reference model to match the MRI dataset. Second, we present simulating knee motion that visualizes patient-specific motion data on the patient-specific knee model. Third, we introduce visualizing biomechanical information on a patient-specific model. The focus is on visualizing contact area, contact forces, and menisci deformation. Traditional methods have difficulty in visualizing knee contact area without using invasive methods. The approach presented here provides an alternative of visualizing the knee contact area and forces without any risk to the patient. Finally, a virtual surgery can be performed. The constructed 3-D knee model is the basis of motion simulation, biomechanical visualization, and virtual surgery. Knee motion simulation determines the knee rotation angles as well as knee contact points. These parameters are used to solve the biomechanical model. Our results integrate 3-D construction, motion simulation, and biomechanical visualization into one system. Overall, the methodologies here are useful elements for future virtual medical systems where all the components of visualization, automated model generation, and surgery simulation come together.

NO regulates LPS-stimulated cyclooxygenase gene expression and activity in pulmonary artery endothelium

We examined whether nitric oxide (NO) inhibits prostanoid synthesis through actions on cyclooxygenase (COX) gene expression and activity. Bovine pulmonary artery endothelial cells were pretreated for 30 min with the NO donors 1 mM S-nitroso-N-acetylpenicillamine (SNAP), 0.5 mM sodium nitroprusside (SNP), or 0.2 microM spermine NONOate; controls included cells pretreated with either 1 mM N-acetyl-D-penicillamine or the NO synthase (NOS) inhibitor 1 mM N(G)-nitro-L-arginine methyl ester with and without addition of lipopolysaccharide (LPS; 0.1 microg/ml) for 8 h. COX-1 and COX-2 gene and protein expression were examined by RT-PCR and Western analysis, respectively; prostanoid measurements were made by gas chromatography-mass spectrometry, and COX activity was studied after a 30-min incubation with 30 microM arachidonic acid. LPS induced COX-2 gene and protein expression and caused an increase in COX activity and an eightfold increase in 6-keto-PGF(1alpha) release. LPS-stimulated COX-2 gene expression was decreased by approximately 50% by the NO donors. In contrast, LPS caused a significant reduction in COX-1 gene expression and treatment with NO donors had little effect. SNAP, SNP, and NONOate significantly suppressed LPS-stimulated COX activity and 6-keto-PGF(1alpha) release. Our data indicate that increased generation of NO attenuates LPS-stimulated COX-2 gene expression and activity, whereas inhibition of endogenous NOS has little effect.

Induction of heme oxygenase-1 by Ginkgo biloba extract but not its terpenoids partially mediated its protective effect against lysophosphatidylcholine-induced damage

In this study, we examined whether Ginkgo Biloba Extract and its terpenoid constituents protect against oxidative stress through actions on heme oxygenase (HO) gene expression and activity. HO-1 and glutathione peroxidase (GPx) gene expressions were examined by reverse transcription polymerase chain reaction (RT-PCR) analysis, HO activity and GPx enzyme activity were analysed by spectrophotometric assay. Pretreatment of H9c2 myocytes with 100-500 microgml(-1)Ginkgo Biloba Extract caused induction of HO-1 gene expression and a significant increase in HO activity; 30 microgml(-1)ginkgolide B and 30 microgml(-1)bilobalide had little effect. Treatment with Ginkgo Biloba Extract for 24 h also significantly increased GPx gene expression and GPx enzyme activity. Pretreatment with Ginkgo Biloba Extract, ginkgolide B and bilobalide protected myocytes against lysophosphatidylcholine (LPC)-induced damage. The protective effect of Ginkgo Biloba Extract against LPC-induced damage was partially suppressed by a HO inhibitor, Zinc protoporphyrin-IX (ZnPP-IX), while ZnPP-IX did not suppress the protective effect of ginkgolide B or bilobalide. Furthermore, pretreatment with hemin, biliverdin or bilirubin reduced cytotoxicity induced by LPC. These results suggest that induction of HO-1 by Ginkgo Biloba Extract but not its terpenoid constituents may play a beneficial role in oxidative stress. The mechanism of Ginkgo Biloba Extract-induced HO-1 gene expression and the increase in HO activity may be related to alteration of intracellular glutathione levels.

Nitric oxide donors regulate nitric oxide synthase in bovine pulmonary artery endothelium

This study examined the notion that exogenous generation of nitric oxide (NO) modulates NOS gene expression and activity. Bovine pulmonary artery endothelial cells (BPAEC) were treated with the NO donors, 1 mM SNAP (S-nitroso-N-acetylpenicillamine), 0.5 mM SNP (sodium nitroprusside) or 0.2 microM NONOate (spermine NONOate) in medium 199 containing 2% FBS. Controls included untreated cells and cells exposed to 1 mM NAP (N-acetyl-D-penicillamine). NOS activity was assessed using a fibroblast-reporter cell assay; intracellular Ca2+ concentrations were assessed by Fura-2 microfluorometry; and NO release was measured by chemiluminescence. Constitutive endothelial (e) and inducible (i) NOS gene and protein expression were examined by northern and western blot analysis, respectively. Two hours exposure to either SNAP or NONOate caused a significant elevation in NO release from the endothelial cells (SNAP = 51.4 +/- 5.9; NONOate = 23.8 +/- 4.2; control = 14.5 +/- 2.8 microM); but A23187 (3 microM)-stimulated NO release was attenuated when compared to controls. Treatment with either SNAP or NONOate for 2 h also resulted in a significant increase in NOS activity in endothelial homogenates (SNAP = 23.6 +/- 2.5; NONOate= 29.8 +/- 7.7; control = 14.5 +/- 2.5fmol cGMP/microg per 10(6) cells). Exposure to SNAP and SNP, but not NONOate, for 1 h caused an increase in intracellular calcium. Between 4 and 8 h, SNAP and NONOate caused a 2- to 3-fold increase in eNOS, but not iNOS, gene (P < 0.05) and protein expression. NAP had little effect on either eNOS gene expression, activity or NO production. Our data indicate that exogenous generation of NO leads to a biphasic response in BPAEC, an early increase in intracellular Ca2+, and increases in NOS activity and NO release followed by increased expression of the eNOS gene, but not the iNOS gene. We conclude that eNOS gene expression and activity are regulated by a positive-feedback regulatory action of exogenous NO.

Both (+/-)syn- and (+/-)anti-7,12-dimethylbenz[a]anthracene-3,4-diol-1,2-epoxides initiate tumors in mouse skin that possess -CAA- to -CTA- mutations at Codon 61 of c-H-ras

We have determined the tumor-initiating activity of (+/-)syn- and (+/-)anti-7,12-dimethylbenz[a]anthracene-3,4-diol-1,2-epoxide (syn- and anti-DMBADE), the two metabolically formed bay-region diol epoxides of DMBA, and we have also analyzed mutations in the H-ras gene from tumors induced by these compounds. Using a two-stage, initiation-promotion protocol for tumorigenesis in mouse skin, we have found that both syn- and anti-DMBADE are active tumor initiators, and that the occurrence of papillomas is carcinogen dose dependent. All of the papillomas induced by syn-DMBADE (a total of 40 mice), 96% of those induced by anti-DMBADE (a total of 25 mice), and 94% of those induced by DMBA (a total of 16 mice) possessed a -CAA- to -CTA- mutation at codon 61 of H-ras. No mutations in codons 12 or 13 were detected in any tumor. Topical application of syn- and anti-DMBADE produced stable adducts in mouse epidermal DNA, most of which comigrated with stable DNA adducts formed after topical application of DMBA. Further analysis of the data showed that levels of the major syn- and anti-DMBADE-deoxyadenosine adducts formed after topical application of DMBA are sufficient to account for the tumor-initiating activity of this carcinogen on mouse skin. Previously, we showed that both the syn- and anti-DMBADE bind to the adenine (A182) at codon 61 of H-ras. Collectively, these results indicate that the adenine adducts induced by both bay-region diol epoxides of DMBA lead to the mutation at codon 61 of H-ras and, consequently, initiate tumorigenesis in mouse skin.

Inhibitory effects of nitric oxide and nitrosative stress on dopamine-beta-hydroxylase

Dopamine-beta-hydroxylase (DbetaH) is a copper-containing enzyme that uses molecular oxygen and ascorbate to catalyze the addition of a hydroxyl group on the beta-carbon of dopamine to form norepinephrine. While norepinephrine causes vasoconstriction following reflex sympathetic stimulation, nitric oxide (NO) formation results in vasodilatation via a guanylyl cyclase-dependent mechanism. In this report, we investigated the relationship between NO and DbetaH enzymatic activity. In the initial in vitro experiments, the activity of purified DbetaH was inhibited by the NO donor, diethylamine/NO (DEA/NO), with an IC(50) of 1 mm. The inclusion of either azide or GSH partially restored DbetaH activity, suggesting the involvement of the reactive nitrogen oxide species, N(2)O(3). Treatment of human neuroblastoma cells (SK-N-MC) with diethylamine/NO decreased cellular DbetaH activity without affecting their growth rate and was augmented by the depletion of intracellular GSH. Co-culture of the SK-N-MC cells with interferon-gamma and lipopolysaccharide-activated macrophages, which release NO, also reduced the DbetaH activity in the neuroblastoma cells. Our results are consistent with the hypothesis that nitrosative stress, mediated by N(2)O(3), can result in the inhibition of norepinephrine biosynthesis and may contribute to the regulation of neurotransmission and vasodilatation.

Substance use and socio-demographic factors among aboriginal and Torres Strait Islander school students in New South Wales

OBJECTIVE

To estimate prevalence rates of substance use and associated socio-demographic factors among Aboriginal and Torres Strait Islander (ATSI) secondary students.

METHOD

This paper presents ATSI data from population-based school surveys conducted in 1996, 1992 and 1989 in New South Wales and replicates identical analysis using the three datasets.

RESULTS

The proportion of ATSI students in each survey ranged from 2.5% to 3.8%. After adjusting for age, gender and socio-demographic factors, ATSI students were more likely to smoke cigarettes, and to have tried cannabis and other illicit substances.

CONCLUSIONS

This study suggests that Aboriginal and Torres Strait Islander students were more susceptible to, and maintained a higher rate of, substance use than non-Aboriginal and Torres Strait Islander youth. Socio-demographic differences between Aboriginal and non-Aboriginal students in age, rural/urban status, living with both parents, reporting poor school performance, low parental supervision and high school absenteeism remained significantly associated with Aboriginal status and substance use.

IMPLICATIONS

This is one of the first studies examining substance use in a large and representative sample of in-school ATSI youth. These results provide information useful for public health advocates, and require policy changes more likely to reduce substance use among ATSI youth.

Inhibition of in vitro enteric neuronal development by endothelin-3: mediation by endothelin B receptors

The terminal colon is aganglionic in mice lacking endothelin-3 or its receptor, endothelin B. To analyze the effects of endothelin-3/endothelin B on the differentiation of enteric neurons, E11-13 mouse gut was dissociated, and positive and negative immunoselection with antibodies to p75(NTR)were used to isolate neural crest- and non-crest-derived cells. mRNA encoding endothelin B was present in both the crest-and non-crest-derived cells, but that encoding preproendothelin-3 was detected only in the non-crest-derived population. The crest- and non-crest-derived cells were exposed in vitro to endothelin-3, IRL 1620 (an endothelin B agonist), and/or BQ 788 (an endothelin B antagonist). Neurons and glia developed only in cultures of crest-derived cells, and did so even when endothelin-3 was absent and BQ 788 was present. Endothelin-3 inhibited neuronal development, an effect that was mimicked by IRL 1620 and blocked by BQ 788. Endothelin-3 failed to stimulate the incorporation of [3H]thymidine or bromodeoxyuridine. Smooth muscle development in non-crest-derived cell cultures was promoted by endothelin-3 and inhibited by BQ 788. In contrast, transcription of laminin alpha1, a smooth muscle-derived promoter of neuronal development, was inhibited by endothelin-3, but promoted by BQ 788. Neurons did not develop in explants of the terminal bowel of E12 ls/ls (endothelin-3-deficient) mice, but could be induced to do so by endothelin-3 if a source of neural precursors was present. We suggest that endothelin-3/endothelin B normally prevents the premature differentiation of crest-derived precursors migrating to and within the fetal bowel, enabling the precursor population to persist long enough to finish colonizing the bowel.

Probucol inhibits oxidized-low density lipoprotein-induced adhesion of monocytes to endothelial cells by reducing P-selectin synthesis in vitro

Probucol (PBC) is an unique antiatherogenic drug producing its effect by antioxidant action rather than hypolipidaemic effect. However, the exact mechanism of its antiatherogenic effect is unclear. Therefore we investigated the PBC effects on the adhesion of monocytes to endothelial cells, an early event in atherogenesis. Monocyte adhesion to cultured pig aortic endothelial cells (EC) was induced by oxidized low density lipoprotein (Ox-LDL). To elucidate the mechanisms of the inhibition on adhesion, PBC effects on the Ox-LDL-induced expression of P-selectin, on the synthesis of von Willebrand factor (vWF) and prostacyclin (PGI2) were examined. The results showed that Ox-LDL enhanced the adhesion of monocytes to EC in a concentration-dependent and time-related manner. PBC 25, 50 and 75 micromol/L inhibited the Ox-LDL-induced adhesion index from 37.3% to 19.7, 16.6 and 14.6% respectively (p all < 0.05), and inhibited the Ox-LDL-induced expression of P-selectin from 293.0 ng/ml to 180.0, 132.9 and 132.6 ng/ml respectively. Furthermore, PBC significantly attenuated the Ox-LDL-impaired synthesis of PGI2 and vWF. These results indicate that PBC may provide a new approach in the prevention of atherosclerosis (AS) by intervention of monocyte adhesion to EC. In conclusion, PBC inhibits the Ox-LDL-induced adhesion of monocytes to EC. This effect is associated with the inhibition of the Ox-LDL-induced expression of P-selectin and the protection on the synthesis of PGI2.

Guinea pig 5-HT transporter: cloning, expression, distribution, and function in intestinal sensory reception

Studies of the guinea pig small intestine have suggested that serotonin (5-HT) may be a mucosal transmitter that stimulates sensory nerves and initiates peristaltic and secretory reflexes. We tested the hypothesis that guinea pig villus epithelial cells are able to inactivate 5-HT because they express the same 5-HT transporter as serotonergic neurons. A full-length cDNA, encoding a 630-amino acid protein (89.2% and 90% identical, respectively, to the rat and human 5-HT transporters) was cloned from the guinea pig intestinal mucosa. Evidence demonstrating that this cDNA encodes the guinea pig 5-HT transporter included 1) hybridization with a single species of mRNA ( approximately 3.7 kb) in Northern blots of the guinea pig brain stem and mucosa and 2) uptake of [3H]5-HT by transfected HeLa cells via a saturable, high-affinity (Michaelis constant 618 nM, maximum velocity 2.4 x 10(-17) mol . cell-1 . min-1), Na+-dependent mechanism that was inhibited by chlorimipramine > imipramine > fluoxetine > desipramine > zimelidine. Expression of the 5-HT transporter in guinea pig raphe and enteric neurons and the epithelium of the entire crypt-villus axis was demonstrated by in situ hybridization and immunocytochemistry. Inhibition of mucosal 5-HT uptake potentiates responses of submucosal neurons to mucosal stimulation. The epithelial reuptake of 5-HT thus appears to be responsible for terminating mucosal actions of 5-HT.

Protective effects of Ginkgo biloba extract against lysophosphatidylcholine-induced vascular endothelial cell damage

AIM

To study the protective effects of Ginkgo biloba extract (GbE) against endothelial cell damage induced by lysophosphatidylcholine (LPC).

METHODS

The vasorelaxation response to acetylcholine (ACh) were investigated in the isolated rabbit thoracic aorta. Lipid peroxidation products were determined by measuring thiobarbituric acid reactive substance.

RESULTS

GbE attenuated the inhibition of vasorelaxation response to ACh and prevented the LPC-induced increase of malondialdehyde (MDA) content both in thoracic aortae. GbE prevented the leakage of LDH and the increase of MDA content in cultured endothelial cells in a concentration-dependent manner. GbE also markedly increased epoprostenol level in cultured endothelial cells treated with LPC.

CONCLUSION

GbE protected endothelial cells against LPC-induced damage due to reduction in lipid peroxidation and facilitation of synthesis and/or release of epoprostenol.

Carcinogens preferentially bind at methylated CpG in the p53 mutational hot spots

The major mutational hot spots in human cancers occur at CpG sequences in the p53 gene. It is generally presumed that the majority of mutations at these sites result from the endogenous deamination of methylated cytosine. Using a UvrABC incision method, we have found that cytosine methylation greatly enhances guanine alkylation at all CpG sites in the p53 gene by a variety of carcinogens, including benzo(a)pyrene diol epoxide, benzo(g)chrysene diol epoxide, aflatoxin B1 8,9-epoxide, and N-acetoxy-2-acetylaminofluorene. These findings suggest that mutational hot spots at methylated CpG sequences in the p53 gene may be a consequence of preferential carcinogen binding at these sites.

The usefulness of technetium-99m-MIBI scintimammography in diagnosis of breast cancer: using surgical histopathologic diagnosis as the gold standard

The purpose of this study was to evaluate the usefulness of 99mTc-MIBI scintinammography for the detection of breast cancer.

METHODS

Sixty-one consecutive patients referred for a suspicions breast lesion on clinical examination were studied with 99mTc-MIBI scintimammography. There were 60 female patients and 1 male patient with 63 pulpable breast abnormalities. Each patient received 20mCi 99mTc-MIBI intravenously. Ten and 120 minutes postinjection, three planar views, right and left lateral prone and anterior supine thoracic views, were obtained. The patient underwent surgery within one week and the final diagnostic results (histopathology) were obtained.

RESULTS

Thirty-two of 63 abnormalities of breast were pathologically confirmed breast cancer, and 31 were benign lesions. In the group of patients studied, the sensitivity of 99mTc-MIBI scintimammography was 78.1% (25 true-positive, 7 false-negative) and the specificity was 90.3% (28 true-negative, 3 false positive). The positive predictive value was 89.3%, the negative predictive value was 80.0%, the positive likelihood ratio was 8.1, the negative likelihood ratio was 0.2.

CONCLUSION

This study showed the high diagnostic accuracy of 99mTc-MIBI scintimammography in detecting breast cancer. 99mTc-MIBI scintimammography can be used as an assistant method to non-invasively assess breast cancer invasiveness before surgery.

Sites of preferred interaction between double-stranded pBR322 DNA and 7-methylpyrido[3,4-c]psoralen

7-Methylpyrido[3,4-c]psoralen has recently been found to photosensitize the crosslinking and cleavage of double-stranded pBR322 DNA (4361 bp) with an unusual degree of site specificity. Following cleavage of the photosensitized pBR322 with the restriction enzymes Pvu II and BamH I, the main fragments were analyzed electrophoretically. Only three possible cleavage areas on the plasmid were suggested by this analysis. They were within the ranges bounded by the positions 801-926, 3172-3303 and 4226-4310. The sensitizer also induced selective cleavage in the related plasmid pUC19 (2686 bp), but the pattern was somewhat more complicated and was not analyzed in detail.

Cytosine methylation determines hot spots of DNA damage in the human P53 gene

In the P53 tumor suppressor gene, a remarkably large number of somatic mutations are found at methylated CpG dinucleotides. We have previously mapped the distribution of (+/-) anti-7beta,8alpha-dihydroxy-9alpha,10alpha-epoxy -7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) adducts along the human P53 gene [Denissenko, M. F., Pao, A., Tang, M.-s. & Pfeifer, G. P. (1996) Science 274, 430-432]. Strong and selective formation of adducts occurred at guanines in CpG sequences of codons 157, 248, and 273, which are the major mutational hot spots in lung cancer. Chromatin structure was not involved in preferential modification of these sites by BPDE. To investigate other possible mechanisms underlying the selectivity of BPDE binding, we have mapped the adducts in plasmid DNA containing genomic P53 sequences. The adduct profile obtained was different from that in genomic DNA. However, when cytosines at CpG sequences were converted to 5-methylcytosines by the CpG-specific methylase SssI and the DNA was subsequently treated with BPDE, adduct hot spots were created which were similar to those seen in genomic DNA where all CpGs are methylated. A strong positive effect of 5-methylcytosine on BPDE adduct formation at CpG sites was also documented with sequences of the PGK1 gene derived from an active or inactive human X chromosome and having differential methylation patterns. These results show that methylated CpG dinucleotides, in addition to being an endogenous promutagenic factor, may represent a preferential target for exogenous chemical carcinogens. The data open new avenues concerning the reasons that the majority of mutational hot spots in human genes are at CpGs.

Using UvrABC nuclease to detect 7,12-dimethylbenz[a]anthracene anti-diol epoxide-DNA binding specificity in the mouse H-ras gene

DNA fragments modified with chemically synthesized 7,12-dimethylbenz[a]anthracene anti-diol epoxide (anti-DMBADE) are sensitive to UvrABC nuclease incision. The incisions occur mainly 7 bases 5' and 4 bases 3' of an anti-DMBADE-modified adenine or guanine residue, and the kinetics of incision at different sequences in a DNA fragment are the same. These results indicate that UvrABC incision on anti-DMBADE-DNA adducts is independent of DNA sequences and is quantitative, the same as on syn-DMBADE-DNA adducts. This method was used to analyze the anti-DMBADE-DNA binding spectrum in the exon 2 region of the mouse H-ras gene, and it was found that anti-DMBADE binds to the two adenine residues at codon 61 of the H-ras gene with an average affinity. Previously, we have demonstrated that syn-DMBADE binds strongly to the adenines at codon 61 of H-ras; these results together suggest that the oncogenic mutation in H-ras may be induced by anti- and syn-DMBADE-DNA adducts.

Sequence preference of 7,12-dimethylbenz[a]anthracene-syn-diol epoxide-DNA binding in the mouse H-ras gene detected by UvrABC nucleases

We have found that 7,12-dimethylbenz[a]anthracene-syn-diol epoxide (syn-DMBADE)-modified DNA fragments are sensitive to UvrABC incision. The incisions occur mainly seven bases 5' and four bases 3' of a syn-DMBADE-modified adenine or guanine residue. The kinetics of UvrABC incision at different sequences in a DNA fragment are the same, and the extent of UvrABC incision is proportional to the syn-DMBADE concentration. On the basis of these results, we have concluded that UvrABC incision on syn-DMBADE-DNA adducts is independent of DNA sequence and is quantitative. Using the UvrABC incision method, we have analyzed the syn-DMBADE-DNA binding spectrum in several defined DNA fragments, including the first two exons of the mouse H-ras gene. We have found that both guanine and adenine residues in codons 12, 13, and 61 of the H-ras gene are strong syn-DMBADE binding sites. These results suggest that the initial binding of DMBADE may greatly contribute to the frequency of H-ras mutations. Results from dinucleotide binding analysis indicate that the 5'-nearest neighbor displays a greater effect on syn-DMBADE-DNA binding than the 3'-nearest neighbor.

The receptor for advanced glycation end products (RAGE) is a cellular binding site for amphoterin. Mediation of neurite outgrowth and co-expression of rage and amphoterin in the developing nervous system

The receptor for advanced glycation end products (RAGE), a newly-identified member of the immunoglobulin superfamily, mediates interactions of advanced glycation end product (AGE)-modified proteins with endothelium and other cell types. Survey of normal tissues demonstrated RAGE expression in situations in which accumulation of AGEs would be unexpected, leading to the hypothesis that under physiologic circumstances, RAGE might mediate interaction with ligands distinct from AGEs. Sequential chromatography of bovine lung extract identified polypeptides with M(r) values of approximately 12,000 (p12) and approximately 23,000 (p23) which bound RAGE. NH2-terminal and internal protein sequence data for p23 matched that reported previously for amphoterin. Amphoterin purified from rat brain or recombinant rat amphoterin bound to purified sRAGE in a saturable and dose-dependent manner, blocked by anti-RAGE IgG or a soluble form of RAGE (sRAGE). Cultured embryonic rat neurons, which express RAGE, displayed dose-dependent binding of 125I-amphoterin which was prevented by blockade of RAGE using antibody to the receptor or excess soluble receptor (sRAGE). A functional correlate of RAGE-amphoterin interaction was inhibition by anti-RAGE F(ab')2 and sRAGE of neurite formation by cortical neurons specifically on amphoterin-coated substrates. Consistent with a potential role for RAGE-amphoterin interaction in development, amphoterin and RAGE mRNA/antigen were co-localized in developing rat brain. These data indicate that RAGE has physiologically relevant ligands distinct from AGEs which are likely, via their interaction with the receptor, to participate in physiologic processes outside of the context of diabetes and accumulation of AGEs.

Hypoxia and modification of the endothelium: implications for regulation of vascular homeostatic properties

Hypoxia is a common denominator of ischemic microenvironments. Endothelium subjected to oxygen deprivation maintains cell viability and basic biosynthetic mechanisms, but displays multiple changes in properties relevant to vascular homeostasis, including suppression of the anticoagulant cofactor thrombomodulin, decreased barrier function, and generation of proinflammatory cytokines. Diminished intracellular cAMP during the period of hypoxia and lowered nitric oxide/cGMP in the subsequent reperfusion period are proposed as fundamental mechanisms driving vascular dysfunction impacting on coagulation, permeability, vasomotor tone and leukocyte adhesivity. The period of organ preservation for transplantation, recognized to be associated with hypoxia, primes mechanisms leading to subsequent vascular dysfunction which can be ameliorated by buttressing cAMP and nitric oxide/cGMP intra- and intercellular second messenger systems. A mechanism likely to contribute to hypoxia-mediated generation of cytokines, such as interleukin 6, is activation of the transcription factor NF-IL-6, which occurs in oxygen deprivation. These data indicate that study of cellular mechanisms of endothelial perturbation in hypoxia is likely to provide insights ultimately applicable to ischemia-induced vascular damage.

Advanced glycation endproducts interacting with their endothelial receptor induce expression of vascular cell adhesion molecule-1 (VCAM-1) in cultured human endothelial cells and in mice. A potential mechanism for the accelerated vasculopathy of diabetes

Vascular cell adhesion molecule-1 (VCAM-1), an inducible cell-cell recognition protein on the endothelial cell surface (EC), has been associated with early stages of atherosclerosis. In view of the accelerated vascular disease observed in patients with diabetes, and the enhanced expression of VCAM-1 in diabetic rabbits, we examined whether irreversible advanced glycation endproducts (AGEs), could mediate VCAM-1 expression by interacting with their endothelial cell receptor (receptor for AGE, RAGE). Exposure of cultured human ECs to AGEs induced expression of VCAM-1, increased adhesivity of the monolayer for Molt-4 cells, and was associated with increased levels of VCAM-1 transcripts. The inhibitory effect of anti-RAGE IgG, a truncated form of the receptor (soluble RAGE) or N-acetylcysteine on VCAM-1 expression indicated that AGE-RAGE-induced oxidant stress was central to VCAM-1 induction. Electrophoretic mobility shift assays on nuclear extracts from AGE-treated ECs showed induction of specific DNA binding activity for NF-kB in the VCAM-1 promoter, which was blocked by anti-RAGE IgG or N-acetylcysteine. Soluble VCAM-1 antigen was elevated in human diabetic plasma. These data are consistent with the hypothesis that AGE-RAGE interaction induces expression of VCAM-1 which can prime diabetic vasculature for enhanced interaction with circulating monocytes.

Effects of gypenosides on mouse splenic lymphocyte transformation and DNA polymerase II activity in vitro

AIM

To study the effects of gypenosides (Gyp) on lymphocyte transformation and DNA polymerase II activity.

METHODS

Lymphocyte transformation response was induced by concanavalin A and lipopolysaccharides respectively. The activity of DNA polymerase II and DNA synthesis were assayed with TTP and [3H]TdR incorporation respectively in mixed lymphocyte culture test.

RESULTS

Gyp 2.5-20 mg L-1 enhanced splenic T- and B- cell transformation, increased the DNA synthesis and potentiated the activity of DNA polymerase II. However, Gyp > 40 mg L-1 showed contrary effects.

CONCLUSION

Gyp regulated lymphocyte transformation and DNA synthesis by regulating DNA polymerase II activity.

[Therapy of cantharides extract for perennial allergic rhinitis and its effect on total IgE in serum]

The therapy of 10% Cantharides extract in treating 50 cases of perennial allergic rhinitis (PAR) was studied. The extract was plastered and blistered on Dazhui, Neiguan point. It was observed by nasal mucosa provocative test, cells in nasal secretion test and serum total IgE test. The results showed that its effective rate was 88%, the allergic nasal mucosa provocative test of treated group alleviated obviously after the treatment (P < 0.01), the number of eosinophil and basophil in nasal secretion decreased (P < 0.01, P < 0.05); and the serum total IgE also reduced significantly (P < 0.01).