Inhibitory effect of green tea extract on beta-amyloid-induced PC12 cell death by inhibition of the activation of NF-kappaB and ERK/p38 MAP kinase pathway through antioxidant mechanisms

Beta-amyloid peptide (Abeta) is considered responsible for the pathogenesis of Alzheimer's disease (AD). Several lines of evidence support that Abeta-induced cytotoxicity is mediated through the generation of reactive oxygen species (ROS). Thus, agents that scavenge ROS level may usefully impede the development or progress of AD. Green tea extract has been known to have such antioxidant properties. Our previous studies demonstrate that green tea extract protected ischemia/reperfusion-induced brain cell death by scavenging oxidative damages of macromolecules. In this study, we investigated the effects of green tea extract on Abeta-induced oxidative cell death in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with Abeta25-35 (10-50 microM) showed intracellular ROS elevation, the formation of 8-oxodG (an oxidized form of DNA), and underwent apoptotic cell death in a dose-dependent manner. Abeta(25-35) treatment upregulated pro-apoptotic p53 at the gene level, and Bax and caspase-3 at the protein level, but downregulated anti-apoptotic Bcl-2 protein. Interestingly, co-treated green tea extract (10-50 microg/ml) dose-dependently attenuated Abeta(25-35) (50 microM)-induced cell death, intracellular ROS levels, and 8-oxodG formation, in addition to p53, Bax, and caspase-3 expression, but upregulated Bcl-2. Furthermore, green tea extract prevented the Abeta(25-35)-induced activations of the NF-kappaB and ERK and p38 MAP kinase pathways. Our study suggests that green tea extract may usefully prevent or retard the development and progression of AD.     

Dose-volumetric parameters for predicting severe radiation pneumonitis after three-dimensional conformal radiation therapy for lung cancer

PURPOSE: To retrospectively evaluate dose-volumetric parameters for association with risk of severe (grade >/=3) radiation pneumonitis (RP) in patients after three-dimensional (3D) conformal radiation therapy for lung cancer. MATERIALS AND METHODS: The study was approved by the institutional review board, which did not require informed consent. Data from 76 patients (66 men, 10 women; median age, 60 years; range, 35-79 years) with histologically proved lung cancer treated curatively with 3D conformal radiation therapy between August 2001 and October 2002 were retrospectively analyzed. Twenty patients underwent surgery before radiation therapy; 57 patients received chemotherapy. Median total radiation dose of 60 Gy (range, 54-66 Gy) was delivered in 30 (range, 27-33) fractions over 6 weeks. RP was scored by using Radiation Therapy Oncology Group criteria. Clinical parameters were analyzed. Dose-volumetric parameters analyzed were percentage of lung volume that received a dose of 20 Gy or more (V20), 30 Gy or more (V30), 40 Gy or more (V40), or 50 Gy or more (V50); mean lung dose (MLD); normal tissue complication probability (NTCP); and total dose. Fisher exact test was performed to compare clinical parameters between patients who developed severe RP and those who did not. Univariate and multivariate logistic regression analyses were performed to evaluate data for association between dose-volumetric parameters and severe RP. Pearson chi(2) test was used to assess data for correlations among dose-volumetric parameters. P < or = .05 was considered to indicate statistically significant difference. RESULTS: Of 76 patients, 30 (39%) did not develop RP; 23 (30%) developed RP of grade 1; 11 (14%), grade 2; 11 (14%), grade 3; and 1 (1%), grade 4. None had grade 5 RP. Age (< 60 vs > or =60), sex, Karnofsky performance status (< 70 vs > or =70), forced expiratory volume in 1 second, presence of weight loss, preexisting lung disease, history of thoracic surgery, and history of chemotherapy did not significantly differ between patients who developed severe RP and those who did not. In univariate analyses, MLD, V20, V30, V40, V50, and NTCP were associated with severe RP (P < .05). In multivariate analysis, MLD was the only variable associated with severe RP. CONCLUSION: MLD is a useful indicator of risk for development of severe RP after 3D conformal radiation therapy in patients with lung cancer.     

p53 and p21 genetic polymorphisms and susceptibility to endometrial cancer

OBJECTIVE: Recently, there has been considerable interest in the association of specific cancers with single nucleotide polymorphisms (SNPs). In this regard, genetic polymorphism at codon 72 (CCC/proline to CGC/arginine [Pro(72)Arg]) of the p53 gene is one of the most frequently studied subjects. An association between endometrial cancer and the polymorphism at codon 31 (AGC/serine to AGA/arginine [Ser(31)Arg]) of the p21 gene, which is known to be a downstream mediator of p53, has also been reported. METHODS: The authors designed a hospital-based case-control study of 95 endometrial cancer patients and 285 non-cancer controls. For the determination of p53 and p21 polymorphism, allele-specific polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism assay was applied, respectively. RESULTS: We found statistically significant differences in the frequency of the p53 and p21 genotypes between these two groups (P < 0.001), respectively. The p53 genotypes containing the Pro allele were significantly associated with endometrial cancer with an odds ratio (OR) of 3.56 (95% confidence interval [CI] 2.10-6.04). Also, homozygous carriers of the p21 Ser allele showed a substantially increased risk of developing endometrial cancer (OR 2.68, 95% CI 1.59-4.51) as compared to homozygous and heterozygous carriers of the Arg allele. In addition, the combination of the pro allele containing genotypes of p53 and the Ser homozygous genotype of p21 posed a remarkably increased risk (OR 9.55, 95% CI 4.30-21.24) of endometrial cancer development. These significant differences were maintained throughout the groups after they were stratified by menopausal status. CONCLUSIONS: These data suggest that there is a significant association between the genetic polymorphisms of p53, p21, and specific combinations of the at-risk genotypes of these genes and the risk of developing endometrial cancer in Korean women.     

Small (<or= 2 cm) hepatic lesions in colorectal cancer patients: detection and characterization on mangafodipir trisodium-enhanced MRI

OBJECTIVE: The purpose of this study was to evaluate whether mangafodipir trisodium (MnDPDP)-enhanced MRI improves the detection and characterization of small ( 2.0 cm). The differences between MnDPDP-enhanced MRI and helical CT with regard to the detection rates for hepatic lesions and metastases and with regard to the false-positive rates for hepatic metastases were analyzed using the McNemar test. The performances of MnDPDP-enhanced MRI and helical CT in indicating metastases of focal liver lesions were analyzed using receiver operating characteristic curves. RESULTS: No statistically significant differences were seen between MnDPDP-enhanced MRI and helical CT in the detection of all hepatic lesions (p = 0.383) and small lesions (p = 0.210). However, concerning the differentiation between benign and metastatic lesions, MnDPDP-enhanced MRI was superior to helical CT both for all hepatic lesions (p = 0.023) and for small lesions (p = 0.015), and remained better when the analyses were restricted to patients with histopathologic confirmation (p = 0.023 for both). MnDPDP-enhanced MRI changed the diagnosis of hepatic metastasis in nine (13.0%) of 69 patients. Of 12 metastases that were found on MnDPDP-enhanced MRI and missed on helical CT, 11 lesions (91.7%) were small. MnDPDP-enhanced MRI showed a significantly greater detection rate than helical CT for small hepatic metastases (p = 0.022). MnDPDP-enhanced MRI was better when the analyses were restricted to patients with histopathologic confirmation (p = 0.043). CONCLUSION: Although MnDPDP-enhanced MRI is equal to helical CT in detection of both all hepatic lesions and small lesions in patients with colorectal carcinoma, it is superior to CT in characterization of the lesions.     

Effects of two tetrahydroisoquinolines (YS-49 and YS-51) on experimental disseminated intravascular coagulation induced by lipopolysaccharide in rats

Disseminated intravascular coagulation (DIC) is a pathological syndrome, which occurs following the uncontrolled widespread activation of blood coagulation, resulting in the intravascular formation of fibrin, which may lead to thrombotic occlusion of small and midsize vessels. The effects of 1-(alpha-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (YS-49, CAS 132836-42-1) and 1-(beta-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetra-hydroisoquinoline (YS-51, CAS 213179-96-5) on the experimental DIC induced by lipopolysaccharide (LPS) in rats, were investigated. The oral administration of YS-49 and YS-51 (10 or 50 mg/kg) attenuated the dramatic increase of serum fibrinogen/fibrin degradation product (FDP) level, the decrease of plasma fibrinogen concentration and the number of platelets in blood and the prolongation of prothrombin time (PT) and activated partial thromboplastin time (aPTT) induced by LPS. The liver and kidney function parameters, aspartate amino-transferase (AST) and blood urea nitrogen (BUN), were also improved with YS-49 and YS-51. The above results suggest that YS-49 and YS-51 have therapeutic potential for DIC and/or accompanying multiple organ failure.     

Anti-inflammatory plant flavonoids and cellular action mechanisms

Plant flavonoids show anti-inflammatory activity in vitro and in vivo. Although not fully understood, several action mechanisms are proposed to explain in vivo anti-inflammatory action. One of the important mechanisms is an inhibition of eicosanoid generating enzymes including phospholipase A2, cyclooxygenases, and lipoxygenases, thereby reducing the concentrations of prostanoids and leukotrienes. Recent studies have also shown that certain flavonoids, especially flavone derivatives, express their anti-inflammatory activity at least in part by modulation of proinflammatory gene expression such as cyclooxygenase-2, inducible nitric oxide synthase, and several pivotal cytokines. Due to these unique action mechanisms and significant in vivo activity, flavonoids are considered to be reasonable candidates for new anti-inflammatory drugs. To clearly establish the therapeutic value in inflammatory disorders, in vivo anti-inflammatory activity, and action mechanism of varieties of flavonoids need to be further elucidated. This review summarizes the effect of flavonoids on eicosanoid and nitric oxide generating enzymes and the effect on expression of proinflammatory genes. In vivo anti-inflammatory activity is also discussed. As natural modulators of proinflammatory gene expression, certain flavonoids have a potential for new anti-inflammatory agents.     

Modulation of murine macrophage function by methamphetamine

The abuse of methamphetamine (MA) is an increasingly growing problem globally and produces serious side effects. In the present study, the immunomodulating effects of MA were examined on murine peritoneal macrophages after MA (5 mg/kg body weight) was administered daily orally for 2 wk. When purified macrophages were stimulated with lipopolysaccharide (LPS), the tumoricidal activity induced by LPS was significantly suppressed by MA. MA also inhibited poly I:C-induced antiviral activity in macrophages and decreased the number of peritoneal macrophages. FACS analysis showed that the expression of CD14 was markedly decreased by MA in LPS-stimulated macrophages. The production of nitric oxide (NO) and tumor necrosis factor (TNF)-alpha: which are known to be major effector molecules in macrophage-mediated cytotoxicity, was decreased by MA. MA produced a significant effect on phagocytosis and interleukin-1 (IL-1) and IL-6 at 14 d. In addition, the level of hydrogen peroxide (H2O2) was not altered by MA. Taken together, these data indicate that MA has a differential immunomodulating effect on macrophage secretory and cellular activities.     

Prenylated flavonoids as tyrosinase inhibitors

In order to find new tyrosinase inhibitors and the effects of prenyl residue on flavonoid molecules, eight prenylated and three synthetic vinylated flavonoids were examined on their inhibitory effect against tyrosinase activity. From the results, kuwanon C, papyriflavonol A, sanggenon D and sophoflavescenol were found to possess the considerable inhibitory activity. Especially, sanggenon D is revealed as a potent inhibitor (IC50 = 7.3 microM), compared to the reference compound, kojic acid (IC50 = 24.8 microM). However, the prenylation with isoprenyl group or the vinylation to flavonoid molecules did not enhance tyrosinase inhibitory activity.