Histone deacetylases induce angiogenesis by negative regulation of tumor suppressor genes

Low oxygen tension influences tumor progression by enhancing angiogenesis; and histone deacetylases (HDAC) are implicated in alteration of chromatin assembly and tumorigenesis. Here we show induction of HDAC under hypoxia and elucidate a role for HDAC in the regulation of hypoxia-induced angiogenesis. Overexpressed wild-type HDAC1 downregulated expression of p53 and von Hippel-Lindau tumor suppressor genes and stimulated angiogenesis of human endothelial cells. A specific HDAC inhibitor, trichostatin A (TSA), upregulated p53 and von Hippel-Lindau expression and downregulated hypoxia-inducible factor-1alpha and vascular endothelial growth factor. TSA also blocked angiogenesis in vitro and in vivo. TSA specifically inhibited hypoxia-induced angiogenesis in the Lewis lung carcinoma model. These results indicate that hypoxia enhances HDAC function and that HDAC is closely involved in angiogenesis through suppression of hypoxia-responsive tumor suppressor genes.

Effect of angiotensin peptides on PAI-1 expression and production in human adipocytes

Angiotensin (Ang) II is the active component of the renin-angiotensin-system (RAS), but its degradation products have also been shown to exhibit biological activity. This system, which mainly controls blood pressure and electrolyte homeostasis, was recently found to be completely expressed in human adipose tissue. The major determinant in the fibrinolytic system is the plasminogen activator inhibitor-1 (PAI-1). Both PAI-1 and components of the RAS are over-expressed in the obese state. We have recently shown that Ang II is able to induce PAI-1 expression and release via the AT1-receptor in human fat cells in primary culture, and have provided the first evidence that two metabolites, Ang III and Ang IV, may have a similar stimulatory effect on PAI-1 release. We have now performed additional experiments to further characterize the role of the angiotensin peptides in the production of PAI-1. Ang III and Ang IV showed a time- and dose-dependent stimulation of PAI-1 protein release. Concomitantly, mRNA-levels were markedly elevated. Using specific receptor blockers, all angiotensin peptides seem to induce PAI-1 expression via the angiotensin receptor subtype 1. However, components of the renin-angiotensin-system seem to play an important role in the control of fibrinolysis in adipose tissue. We conclude that PAI-1 production by adipose tissue may contribute to the elevated thromboembolic risk in obesity.

Inhibitory effect on natural killer activity of microphthalmia transcription factor encoded by the mutant mi allele of mice

The mouse mi locus encodes a basic-helix-loop-helix-leucine zipper-type transcription factor, microphthalmia transcription factor (MITF). Mice of mi/mi genotype express a mutant form of MITF (mi-MITF), whereas mice of tg/tg genotype have a transgene in the 5' flanking region of the mi gene and do not express MITF. Although the mi/mi mouse is deficient in natural killer (NK) activity, it was found that the tg/tg mouse was normal in this respect. To know the cause, spleen cells of both genotypes were compared. Although the proportion of spleen cells expressing an NK cell marker, NK1.1, was comparable in both mice, the proportion of large granular lymphocytes decreased only in mi/mi mice. The difference between mi/mi and tg/tg mice was reproducible in the culture supplemented with interleukin-2. Moreover, the perforin gene expression was reduced in mi/mi-cultured spleen cells. Wild-type (+) MITF transactivated, but mi-MITF suppressed, the perforin gene promoter through the NF-P motif, a strong cis-acting element. However, neither +-MITF nor mi-MITF bound the NF-P motif. Instead, 2 nuclear factors that bound the NF-P motif were retained in the cytoplasm of mi/mi-cultured spleen cells. In addition, overexpression of mi-MITF resulted in cytoplasmic retention of the 2 NF-P motif-binding factors in cytotoxic T lymphocytes. The presence of mi-MITF rather than the absence of +-MITF appeared to lead to poor transactivation of the NF-P motif by intercepting NF-P motif-binding factors. This inhibitory effect of mi-MITF may cause the deficient cytotoxicity of NK cells in mi/mi mice. (Blood. 2001;97:2075-2083)

Inhibition of immunologic and nonimmunologic stimulation-mediated anaphylactic reactions by water extract of white eggplant (solanum melongena)

We investigated the effect of water extract of Solanum melongena(SMWE) on immunologic and nonimmunologic stimulation-mediated anaphylactic reactions. Nonimmunologic anaphylactic reaction was induced by compound 48/80 injection. Oral administration of SMWE (1 g kg(-1)) completely inhibited compound 48/80-induced anaphylactic reaction. Immunologic anaphylactic reaction was generated by sensitizing the skin with anti-dinitrophenyl (DNP) IgE followed 48 h later with an injection of antigen. Oral administration of SMWE (0.01--1 g kg(-1)) significantly inhibited passive cutaneous anaphylactic reaction activated by anti-DNP IgE to between 83.10 +/- 1.67% and 70.17 +/- 2.17%. SMWE (0.01--1 mg ml(-1)) also inhibited histamine release activated by compound 48/80 to between 93 +/- 2.65 and 70 +/- 1.50%. Moreover, SMWE (0.01--1 mg ml(-1)) had a significant inhibitory effect on IgE-induced tumor necrosis factor (TNF)-alpha secretion from rat peritoneal mast cells. These results indicate that SMWE inhibits immunologic and nonimmunologic stimulation-mediated anaphylactic reactions and TNF-alpha secretion from mast cells.

Importance of leucine zipper domain of mi transcription factor (MITF) for differentiation of mast cells demonstrated using mi(ce)/mi(ce) mutant mice of which MITF lacks the zipper domain

The mi transcription factor (MITF) is a basic helix-loop-helix leucine zipper (bHLH-Zip) transcription factor that is important for the development of mast cells. Mast cells of mi/mi genotype express normal amount of abnormal MITF (mi-MITF), whereas mast cells of tg/tg genotype do not express any MITFs. Mast cells of mi/mi mice show more severe abnormalities than those of tg/tg mice, indicating that the mi-MITF possesses the inhibitory function. The MITF encoded by the mi(ce) mutant allele (ce-MITF) lacks the Zip domain. We examined the importance of the Zip domain using mi(ce)/mi(ce) mice. The amounts of c-kit, granzyme B (Gr B), and tryptophan hydroxylase (TPH) messenger RNAs decreased in mast cells of mi(ce)/mi(ce) mice to levels comparable to those of tg/tg mice, and the amounts were intermediate between those of +/+ mice and those of mi/mi mice. Gr B mediates the cytotoxic activity of mast cells, and TPH is a rate-limiting enzyme for the synthesis of serotonin. The cytotoxic activity and serotonin content of mi(ce)/mi(ce) mast cells were comparable to those of tg/tg mast cells and were significantly higher than those of mi/mi mast cells. The phenotype of mi(ce)/mi(ce) mast cells was similar to that of tg/tg mast cells rather than to that of mi/mi mast cells, suggesting that the ce-MITF had no functions. The Zip domain of MITF appeared to be important for the development of mast cells. (Blood. 2001;97:2038-2044)

Sphingolipid metabolic changes during chiral C2-ceramides induced apoptosis in human leukemia cells

N-acetylsphingosine (C2-ceramide) is a synthetic water-soluble ceramide mimicking the activity of natural ceramides. By fixing chiral conformation on carbon numbers 2 and 3 in the ceramide structure, four chiral C2-ceramides naming d-erythro-, l-erythro-, d-threo- and l-threo C2-ceramide were synthesized. We have investigated the chiral effects of these C2-ceramides on the sphingolipid metabolism, particularly on both the sphingolipid biosynthetic pathway and on the degradation pathway. In both HL-60 and U937 cells, the chiral C2-ceramide (10 microM) showed sphingosine accumulation monitored fluoromatrically by a high performance liquid chromatographic separation of the sphingoid bases. Most importantly, in HL-60 cells, l-erythro C2-ceramide induced a 50 fold increase in sphingosine as compared to the control, while l-threo C2-ceramide exhibited a minimal 7-fold increase. In contrast, sphinganine, another sphingoid base, showed less accumulation by any chiral C2-ceramide tested under the same conditions. These results suggested that chiral C2-ceramide primarily acts on the sphingolipid degradation pathway rather than on the sphingolipid biosynthetic route. The strong G0/G1 phase arrest in the cell cycle by treatment of l-erythro C2-ceramide indicates that the blockade of the sphingolipid degradation pathway might be concomitantly involved in the dysfunction of the cell cycle. On the other hand, the fact that all chiral C2-ceramides tested failed to inhibit the activity of sphingosine kinase acting on the removal of sphingosine by producing sphingosine-l-phosphate demonstrates that chiral C2- ceramides may increase sphingosine by activating various ceramidases by which natural ceramides are divided into sphingosine and free fatty acids. However, the precise steps involved in this interaction are still unknown.

Antithrombotic effects of tetramethylpyrazine in in vivo experiments

In this study, tetramethylpyrazine (TMPZ) was effective in reducing the mortality of ADP-induced acute pulmonary thromboembolism in mice when administered intravenously at doses of 40 and 80 microg/g. In addition, intravenous injection of TMPZ (10 microg/g) significantly prolonged the bleeding time by approximately 1.5-fold compared with normal saline in severed mesenteric arteries of rats. Continuous infusion of TMPZ (1 microg/g per min) for 10 minutes also significantly increased the bleeding time approximately 1.6-fold, and the bleeding time returned to baseline within 60 minutes after cessation of TMPZ infusion. On the other hand, platelet thrombi formation was induced by irradiation of mesenteric venules with filtered light in mice pre-treated intravenously with fluorescein sodium (10 microg/kg). When it was intravenously injected, TMPZ (250 microg/g) significantly prolonged the latent period of the induction of platelet plug formation in mesenteric venules. TMPZ (250 microg/g) prolonged occlusion time approximately 1.4-fold (183 +/- 18 seconds) compared with that of normal saline (132 +/- 14 seconds). Furthermore, aspirin (300 microg/g) showed similar activity in the prolongation of occlusion time in this experiment. In conclusion, these results suggest that TMPZ has effective antithrombotic activity in vivo and may be a potential therapeutic agent for arterial thrombosis but must be assessed further for toxicity.

Differential effects of fumonisin B1 on cell death in cultured cells: the significance of the elevated sphinganine

Fumonisins are specific inhibitors of ceramide synthase in sphingolipid metabolism. An alteration in sphingolipid metabolism as a result of fumonisin exposure is related to cell death (Yoo et al., 1992). The objective of this study was to investigate whether elevated free sphinganine levels are related to the sensitivity of cultured cells to fumonisin exposure. Fumonisin B1 elevated the intracellular free sphinganine concentraions in both LLC-PK1 and Chinese hamster ovary (CHO) cells. However, CHO cells are resistant to fumonisin cytotoxicity at 50 microM, while LLC-PK1 cells are sensitive at concentrations greater than 35 microM. The intracellular concentration of free sphinganine in LLC-PK, cells treated at 50 microM fumonisin B1 for 72 h was approximately 1450 pmol/mg protein relative to the 37 pmol observed in the control culture. Under the same conditions, the population of apoptotic cells in the 50 M fumonisin B1-treated culture was approximately 37% of the total compared to 12% in the control. The caspase III-like activity after 72 h in the 50 microM fumonisin B1-exposed culture increased to approximately 50 pmol/mg protein/hr compared to 6 pmol/mg protein/hr in the control. L-cycloserine, a serine palmitoyltransferase inhibitor, reduced the fumonisin B1-stimulated caspase III-like activity down to the control level. Under the same culture conditions, the intracellular concentration of free sphinganine after L-cycloserine plus fumonisin B1 treatment was 140 pmol/mg protein compared to 1450 pmol/mg protein in fumonisin B1 alone. The intracellular concentration of free sphinganine in CHO cells treated with 50 microM fumonisin B1 for 72 h was approximately 460 pmol/mg protein, indicating that the mass amount of elevated free sphinganine in the CHO cells was about 32% of that in LLC-PK1 cells. Adding exogenous sphinganine to the CHO cells along with 50 microM fumonisin B1 treatment for 72 h caused both necrosis and apoptosis. In conclusion, the elevated endogenous sphinganine acts as a contributing factor to the fumonisin-induced cell death.

Enhanced activity of cloned hamster TERT gene promoter in transformed cells

In 7,12-dimethylbenz[a]anthracene-treated hamster pouch epithelial cells, telomerase activity increased within 1 week of treatment and reached a 6-7-fold increase within 3 weeks. To investigate this phenomenon, we have cloned and sequenced the hamster telomerase catalytic subunit (hamTERT) promoter. Transient transfection with different genomic segments upstream of the ATG translation initiation codon linked to the luciferase reporter gene mapped the core promoter within a 250 bp region. Three major transcription initiation sites and several minor sites were found between -42 and -140 bp relative to the ATG site. Like the human and murine TERT promoters, the hamTERT promoter lacks TATA and CAT boxes and all three promoters share similar regulatory factor binding sites. DNase I footprint analysis revealed six protected regions which contain sequences homologous with known transcription factor binding sites. Three protein binding regions (I, II, and III) were essential for the promoter activity. Regions I and III bound to Sp1 and Sp3 transcriptional factors, whereas region II bound to an unknown factor. Transient transfection of a promoter-luciferase plasmid into Drosophila SL2 cells showed that Sp1 and Sp3 regulated the hamster TERT promoter in a concentration-dependent and synergistic manner. Telomerase activity showed a 2-4-fold and 8-10-fold increase in immortalized cells and tumor cells, respectively, but hamTERT expression was only increased 1.7-fold and 2.4-fold, respectively, in the same cells.

Cinnamophilin as a novel antiperoxidative cytoprotectant and free radical scavenger

The antioxidant properties of cinnamophilin were evaluated by studying its ability to react with relevant reactive oxygen species, and its protective effect on cultured cells and biomacromolecules under oxidative stress. Cinnamophilin concentration-dependently suppressed non-enzymatic iron-induced lipid peroxidation in rat brain homogenates with an IC50 value of 8.0+/-0.7 microM and iron ion/ADP/ascorbate-initiated rat liver mitochondrial lipid peroxidation with an IC50 value of 17.7+/-0.2 microM. It also exerted an inhibitory activity on NADPH-dependent microsomal lipid peroxidation with an IC50 value of 3.4+/-0.1 microM without affecting microsomal electron transport of NADPH-cytochrome P-450 reductase. Both 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azo-bis(2-amidinopropane) dihydrochloride-derived peroxyl radical tests demonstrated that cinnamophilin possessed marked free radical scavenging capacity. Cinnamophilin significantly protected cultured rat aortic smooth muscle cells (A7r5) against alloxan/iron ion/H2O2-induced damage resulting in cytoplasmic membranous disturbance and mitochondrial potential decay. By the way, cinnamophilin inhibited copper-catalyzed oxidation of human low-density lipoprotein, as measured by fluorescence intensity and thiobarbituric acid-reactive substance formation in a concentration-dependent manner. On the other hand, it was reactive toward superoxide anions generated by the xanthine/xanthine oxidase system and the aortic segment from aged spontaneously hypertensive rat. Furthermore, cinnamophilin exerted a divergent effect on the respiratory burst of human neutrophil by different stimulators. Our results show that cinnamophilin acts as a novel antioxidant and cytoprotectant against oxidative damage.

Determination of hypoxic region by hypoxia marker in developing mouse embryos in vivo: a possible signal for vessel development

Hypoxia is a well-known signal for angiogenesis, but the recent proposal that hypoxia exists in developing embryonic tissues and that it induces vascular development remains to be proven. In the present study, we demonstrate the presence of hypoxia in normal developing embryos by means of a hypoxia marker, pimonidazole, and its associated antibody. Our data clearly show that hypoxia marker immunoreactivity was highly detected in developing neural tubes, heart, and intersomitic mesenchyme at an early stage of organogenesis, suggesting that hypoxia may exist in the early stages of embryo development. We also found that hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) were spatiotemporally co-localized with possible hypoxic regions in embryos. Investigation of platelet endothelial cell adhesion molecule (PECAM) expression provides evidence that endothelial cells proliferate and form the vessels in the hypoxic region in developing organs. Furthermore, we found that hypoxia induced both HIF-1alpha and VEGF in F9 embryonic stem and differentiated cells. Thus, we suggest that hypoxia may exist widely in developing embryonic tissues and that it may act as a signal for embryonic blood vessel formation in vivo.

Inhibitory action of water soluble fraction of Terminalia chebula on systemic and local anaphylaxis

We investigated the effects of the water soluble fraction of Terminalia chebula (Combretaceae) (WFTC) on systemic and local anaphylaxis. WFTC administered 1h before compound 48/80 injection inhibited compound 48/80-induced anaphylactic shock 100% with doses of 0.01-1.0 g/kg. When WFTC was administered 5 or 10 min after compound 48/80 injection, the mortality also decreased in a dose-dependent manner. Passive cutaneous anaphylaxis was inhibited by 63.5+/-7.8% by oral administration of WFTC (1.0 g/kg). When WFTC was pretreated at concentrations ranging from 0.005 to 1.0 g/kg, the serum histamine levels were reduced in a dose-dependent manner. WFTC (0.01-1.0 mg/ml) also significantly inhibited histamine release from rat peritoneal mast cells (RPMC) by compound 48/80. However, WFTC (1.0 mg/ml) had a significant increasing effect on anti-dinitrophenyl IgE-induced tumor necrosis factor-alpha production from RPMC. These results indicate that WFTC may possess a strong antianaphylactic action.

Inhibitory effects of mast cell-mediated allergic reactions by cell cultured Siberian Ginseng

The crude drug "Siberian Ginseng (SG)" has long been used in empirical Oriental medicine for the nonspecific enhancement of resistance in humans and animals. In this study, we investigated the effect of cell cultured SG by oral administration in mast cell-mediated allergic reactions. SG dose-dependently inhibited compound 48/80-induced systemic allergy with doses of 10(-2) to 1 g/kg 1 h before oral administration. Of special note, SG inhibited systemic allergy with the dose of 1 g/kg by 25%. SG (1 g/kg) also inhibited passive cutaneous allergic reaction by 51%. SG dose-dependently inhibited histamine release from rat peritoneal mast cells. When SG (0.01 mg/ml) was added, the secretion of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 in antidinitrophenyl (DNP) IgE antibody-stimulated mast cells was inhibited 39.5% and 23.3%, respectively. In addition, SG inhibited anti-DNP IgE antibody-stimulated TNF-alpha protein expression in mast cells. Our studies provide evidence that SG may be beneficial in the treatment of various types of allergic diseases.

Tissue-engineered growth of bone by marrow cell transplantation using porous calcium metaphosphate matrices

In this study we investigated not only osteoblastic cell proliferation and differentiation on the surface of calcium metaphosphate (CMP) matrices in vitro but also bone formation by ectopic implantation of these cell-matrix constructs in athymic mice in vivo. Interconnected porous CMP matrices with pores 200 microm in size were prepared to use as scaffolds for rat-marrow stromal-cell attachment. Cell-matrix constructs were cultured in vitro, and cell proliferation and ALPase activities were monitored for 56 days. In addition to their being cultured in vitro, cell-matrix constructs were implanted into subcutaneous sites of athymic mice. In vitro these porous CMP matrices supported the proliferation of osteoblastic cells as well as their differentiation, as indicated by high ALPase activity. In vivo the transplanted marrow cells gave rise to bone tissues in the pores of the CMP matrices. A small amount of woven bone formation was detected first at 4 weeks; osteogenesis progressed vigorously with time, and thick lamellar bones that had been remodeled were observed at 12 weeks. These findings demonstrate the potential for using a porous CMP matrix as a biodegradable scaffold ex vivo along with attached marrow-derived mesenchymal cells for transplantation into a site for bone regeneration in vivo.

The p38 mitogen-activated protein kinase pathway regulates interleukin-6 synthesis in response to tumor necrosis factor in osteoblasts

The induction of interleukin-6 (IL-6), using a proinflammatory cytokine (tumor necrosis factor-alpha), was studied in a human osteoblast cell line (MG-63) in relation to p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-kappaB transcription factor. When added to MG-63 cells, tumor necrosis factor-alpha (TNF-alpha) had a stimulatory effect on the production of IL-6, and this elevation was significantly reduced by SB203580, a specific p38 MAPK inhibitor. In addition, the stimulation of IL-6 release was also reduced by pyrrolidine dithiocarbamate (PDTC) or NF-kappaB SN50, which has been reported to be a potent NF-kappaB inhibitor. Both the NF-kappaB inhibitors in the presence of SB203580 had a more inhibitory effect on IL-6 release. In this study, TNF-alpha stimulated NF-kappaB binding affinity as well as p38 MAP kinase activation, leading to the release of IL-6. However, the specific inhibitor of p38 MAPK, SB203580, had no effect on TNF-alpha-induced NF-kappaB activation and both NF-kappaB inhibitors failed to reduce the p38 MAPK activation in the TNF-alpha-stimulated osteoblasts. In addition, inhibition of p38 MAPK partially, but significantly, impaired TNF-alpha-regulated release of osteocalcin, an important differentiation marker in osteoblasts. These results strongly suggest that both p38 MAPK and NF-kappaB are required in TNF-alpha-induced IL-6 synthesis and that these two TNF-alpha-activated pathways can be primarily dissociated. Furthermore, p38 MAPK may play a significant role in differentiation in MG-63 cells.

Effects of folate supplementation on two provisional molecular markers of colon cancer: a prospective, randomized trial

OBJECTIVES

Dietary folate intake is inversely associated with the risk of colorectal cancer. This study investigated the effect of folate supplementation on genomic DNA methylation and DNA strand breaks in exons 5-8 of the p53 gene of the colonic mucosa, two provisional biomarkers of colon cancer.

METHODS

Twenty subjects with adenomas were randomized to receive either folate (5 mg/day) or placebo for 1 yr after polypectomy. At baseline, 6 months and 1 yr, systemic and colonic measures of folate status were determined, as were the biomarkers mentioned earlier.

RESULTS

Folate supplementation increased serum, red blood cell and colonic mucosal folate concentrations (p < 0.02). Folate supplementation also increased the extent of genomic DNA methylation at 6 months and 1 yr (p = 0.001), whereas placebo administration was associated with an increase in the extent of genomic DNA methylation only at 1 yr. Similarly, folate supplementation decreased the extent of p53 strand breaks in exons 5-8 at 6 months and 1 yr (p < 0.02), whereas placebo administration was associated with a decrease in the extent of p53 strand breaks only at 1 yr.

CONCLUSIONS

Both of these provisional biomarkers of colon cancer underwent accelerated improvement at 6 months with folate supplementation. However, these markers also improved with placebo at 1 yr. Therefore, potential confounding factors that seem to modulate these biomarkers need to be identified and corrected in order for these markers to serve as suitable surrogate endpoints in folate chemoprevention trials.

Independent influence of strain difference and mi transcription factor on the expression of mouse mast cell chymases

Expression of mouse mast cell protease (mMCP) genes was examined with particular attention to the transactivation effect of mi transcription factor (MITF) and the expression differences between C57BL/6 (B6) and WB strains. We had reported the enhancing effect of MITF on the expression of mMCP-4, -5, and -6 genes in cultured mast cells (CMCs) of B6 strain, and in the present study we demonstrated the enhancing effect on the expression of mMCP-2 and -9 genes as well. The enhancing effect of MITF on the expression of mMCP-2, -4, -5, -6, and -9 genes was also detected in CMCs of the WB strain. The regulation of mMCP-2, -4, and -9 genes was localized to a specific promoter element (CANNTG) which was recognized and bound by MITF and which was conserved between the B6 and WB strains. On the other hand, the expression of mMCP-2, -4, and -9 genes was smaller in CMCs of the B6 strain when compared to their expression in CMCs of the WB strain. Although mMCP-5 is a chymase as mMCP-2, -4, and -9, and genes encoding all of the chymases are located on chromosome 14, the mMCP-5 gene was regulated in a manner distinct from mMCP-2, -4, and -9 genes.

Intrathecal midazolam increases the analgesic effects of spinal blockade with bupivacaine in patients undergoing haemorrhoidectomy

In the present double-blind study we aimed to evaluate the postoperative analgesic effects of intrathecal midazolam with bupivacaine following haemorrhoidectomy. Forty-five patients were randomly allocated to one of three groups: the control group received 1 ml of 0.5% heavy bupivacaine plus 0.2 ml of 0.9% saline intrathecally, group BM1 received 1 ml of 0.5% bupivacaine plus 0.2 ml of 0.5% preservative-free midazolam and group BM2 received 1 ml of 0.5% bupivacaine plus 0.4 ml of 0.5% midazolam. Time to first analgesia was significantly greater in the midazolam groups than in the placebo and significantly less in the BM1 group than in the BM2 group.

Hypoglycemia-induced VEGF expression is mediated by intracellular Ca2+ and protein kinase C signaling pathway in HepG2 human hepatoblastoma cells

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that plays a central role in angiogenesis. In this study, we investigated the mechanism of VEGF expression in HepG2 human hepatoblastoma cells under hypoglycemia. The shortage of glucose significantly enhanced VEGF mRNA expression in a time-dependent manner as well as increased DNA-binding activity of AP-1 that plays an important role in VEGF transcription. In addition, treatment of a potent PKC inhibitor, H-7 in glucose-deprived HepG2 cells suppressed hypoglycemia-elevated VEGF expression as well as the increased AP-1 DNA-binding activity. Moreover, we observed that Ca2+ levels remarkably increased under low glucose condition. Consistently, an intracellular Ca2+ chelator, BAPTA/AM significantly decreased hypoglycemia-induced VEGF expression and AP-1 DNA-binding activity. Therefore, these results indicate that increase of intracellular Ca2+ level induces the activation of PKC, which induce the activation of AP-1 leading to the increase of VEGF in glucose-deprived environment. Furthermore, it provides one link in regulation of VEGF with hypoglycemia as well as information to understand how hypoglycemia induces VEGF expression and subsequently leads to tumor angiogenesis.

Studies on gelatin-based sponges. Part III: a comparative study of cross-linked gelatin/alginate, gelatin/hyaluronate and chitosan/hyaluronate sponges and their application as a wound dressing in full-thickness skin defect of rat

Novel cross-linked sponges composed of gelatin/alginate and gelatin/hyaluronate and chitosan/hyaluronate (GH, GA and CH, respectively) were prepared and compared. Six different sponges with or without silver sulfadiazine (AgSD) were applied on the full-thickness dorsal skin defect of Wistar rat. The histology and epidermal wound healing rates of the skin defects were investigated by light microscopy and computerized morphometry 5 and 12 days post-operatively. In our full-thickness wound model (diameter 1 cm), the AgSD-impregnated sponges showed good wound healing performances on the whole. However, there appeared meaningful differences of wound healing between the gelatin-based sponges (GH, GA) and the CH. GH with AgSD was found to show the best wound healing properties as a wound dressing resulting from histological findings and computerized morphometric analysis of epidermal healing.

Water extract of 1:1 mixture of Phellodendron cortex and Aralia cortex has inhibitory effects on oxidative stress in kidney of diabetic rats

Enhanced activity of the lipid peroxidation and oxidative damages have been implicated in the pathogenesis of diabetic kidney complications. We explored to determine whether these changes in diabetic kidney could be prevented by water extract of mixture of Phellodendron cortex and Aralia cortex (P55A). Greatly elevated content of thiobarbituric acid reactive substances (TBARS) and carbonylated protein in kidneys of diabetic rats were significantly reduced by P55A treatment. In addition, abnormally low ratio of GSH/GSSG in diabetic kidneys was elevated to almost normal levels by the treatment with P55A. These results suggest that P55A extracts exert antioxidant effect by reducing lipid peroxidation and protein carbonylation as well as by elevating the ratio of GSF/GSSG in diabetic kidney.

beta-Chitin-based wound dressing containing silver sulfurdiazine

Physical and biological properties of some wound dressing materials based on beta-chitin were studied. Water vapor transmission rates (WVTR), oxygen permeabilities and biodegradation kinetics were examined for film-type samples. WVTR of samples was in the range 2400-2800 g/m2/day. However, oxygen permeabilities of the samples were relatively low. To improve oxygen permeabilities, porous sponge-type wound dressing materials were prepared. In addition, these sponge-type samples contained antimicrobial agents, silver sulfadiazine (AgSD), in order to prevent bacteria infection on a wound surface. Anti-microbacterial tests on agar plate were carried out to confirm the bactericidal capacity of present materials. These materials impregnating AgSD had the complete bactericidal capacity against pseudomonas aeruginosa up to 7 days. Finally, a wound healing effect of beta-chitin-based semi-interpenetrating polymer networks was evaluated from the animal test using the wistar rat in vivo. Histological studies confirm the proliferation of fibroblasts in the wound bed and a distinct reduction in infectious cells.

Using buffy coat for reverse transcriptase-polymerase chain reaction in the diagnosis of dengue virus infection: preliminary study

Using reverse transcriptase-polymerase chain reaction (RT-PCR) to detect and type from viremic human serum samples for dengue virus infection is widely used today. However, a few false-negative results were reported due to very low titers of the virus particle in serum samples. As mononuclear cells, macrophages or monocytes are target cells for dengue virus infection, and the replication of virions can be observed in peripheral leukocytes frequently, the amount of virus particle in buffy coat should be higher than those in serum samples. Here, we describe a procedure in which RNA extraction from the buffy coat of a patient with a false-negative serum sample yielded specific viral RNA amplifiable by RT-PCR, thereby providing an alternative choice for the accurate diagnosis of dengue infection.

Insulin-like growth factor II induces interleukin-6 expression via NFkappaB activation in psoriasis

IGF-II is known to induce the growth of keratinocytes and the level was significantly elevated in the tissue fluid of psoriatic lesion. However, the role of IGF-II in psoriasis is not well defined. Because an inflammatory cytokine, interleukin-6 (IL-6) is overexpressed in psoriatic lesions, we explored whether IGF-II has some role in psoriasis through induction of IL-6. Therefore, the expression of IL-6 was analyzed after treatment of IGF-II in primary cultured psoriatic cells and human keratinocyte cell line, HaCaT. We found that IGF-II induced the IL-6 mRNA expression significantly. To investigate the inducing mechanism of IL-6 by IGF-II, we examined the promoter activity of IL-6 and the DNA binding activity of NFkappaB, a strong regulator of IL-6. Interestingly, IL-6 promoter activity and the binding activity of NFkappaB were remarkably increased by IGF-II. Western blot data that IkappaB was reduced by IGF-II significantly suggest that NFkappaB activation by IGF-II may be mediated through the downregulation of IkappaB. Therefore, these results suggest a novel role of IGF-II in psoriasis possibly by inducing IL-6 through the activation of NFkappaB mediated by downregulation of IkappaB.