Diagnostic Role of Bile Pigment Components in Biliary Tract Cancer

Bile pigment, bilirubin, and biliverdin concentrations may change as a results of biliary tract cancer (BTC) altering the mechanisms of radical oxidation and heme breakdown. We explored whether changes in bile pigment components could help distinguish BTC from benign biliary illness by evaluating alterations in patients with BTC. We collected bile fluid from 15 patients with a common bile duct stone (CBD group) and 63 individuals with BTC (BTC group). We examined the bile fluid’s bilirubin, biliverdin reductase (BVR), heme oxygenase (HO-1), and bacterial taxonomic abundance. Serum bilirubin levels had no impact on the amounts of bile HO-1, BVR, or bilirubin. In comparison to the control group, the BTC group had considerably higher amounts of HO-1, BVR, and bilirubin in the bile. The areas under the curve for the receiver operating characteristic curve analyses of the BVR and HO-1 were 0.832 (p<0.001) and 0.891 (p<0.001), respectively. Firmicutes was the most prevalent phylum in both CBD and BTC, according to a taxonomic abundance analysis, however the Firmicutes/Bacteroidetes ratio was substantially greater in the BTC group than in the CBD group. The findings of this study showed that, regardless of the existence of obstructive jaundice, biliary carcinogenesis impacts heme degradation and bile pigmentation, and that the bile pigment components HO-1, BVR, and bilirubin in bile fluid have a diagnostic significance in BTC. In tissue biopsies for the diagnosis of BTC, particularly for distinguishing BTC from benign biliary strictures, bile pigment components can be used as additional biomarkers.

Circulating microRNAs as biomarkers in bile-derived exosomes of cholangiocarcinoma

Purpose@#In this pilot study, using next-generation sequencing and integrated messenger RNA (mRNA) sequencing, we investigated circulating microRNA (miRNA) expression profiling from bile-derived exosomes to identify dysregulated miRNA signatures and oncogenic pathways and determine their effects on targeted mRNAs in cholangiocarcinoma (CCA).Moreover, we explored the possibility that genetic analysis using bile-derived exosomes may replace gene analysis using tissue. @*Methods@#Bile was collected from a patient with perihilar CCA before curative resection. As a control, bile was collected from a patient with a common bile duct stone. Exosomes were isolated from the bile, and we performed next-generation miRNA sequencing using isolated exosomes. To evaluate miRNA-mRNA interactions, mRNA sequencing was performed using bile fluid in both patients. @*Results@#We identified 22 differentially expressed miRNAs. More than 65% of the predicted mRNA targets of those miRNAs were actually differentially expressed between control and CCA bile samples. In functional pathway analysis, targets of 22 miRNAs were primarily enriched in mitogen-activated protein kinase, platelet derived growth factor, vascular endothelial growth factor, epidermal growth factor receptor, and p53 signaling. In particular, in the functional assessment of miRNAmRNA interactions, RAS pathways, including downstream pathways (PI3K-AKT-mTOR and RAS-RAF-MEK-ERK), were determined to be enriched. @*Conclusion@#Circulating miRNAs in bile-derived exosomes provide new information for the development of miRNA analysis in CCA. These miRNAs may represent the oncogenic characteristics of CCA tissue, enabling them to be used instead of tissue samples for the diagnosis of CCA. Further research investigating circulating miRNAs in bile exosomes may lead to more rational, targeted approaches to treatment.

Circulating microRNAs as biomarkers in bile-derived exosomes of cholangiocarcinoma

Purpose@#In this pilot study, using next-generation sequencing and integrated messenger RNA (mRNA) sequencing, we investigated circulating microRNA (miRNA) expression profiling from bile-derived exosomes to identify dysregulated miRNA signatures and oncogenic pathways and determine their effects on targeted mRNAs in cholangiocarcinoma (CCA).Moreover, we explored the possibility that genetic analysis using bile-derived exosomes may replace gene analysis using tissue. @*Methods@#Bile was collected from a patient with perihilar CCA before curative resection. As a control, bile was collected from a patient with a common bile duct stone. Exosomes were isolated from the bile, and we performed next-generation miRNA sequencing using isolated exosomes. To evaluate miRNA-mRNA interactions, mRNA sequencing was performed using bile fluid in both patients. @*Results@#We identified 22 differentially expressed miRNAs. More than 65% of the predicted mRNA targets of those miRNAs were actually differentially expressed between control and CCA bile samples. In functional pathway analysis, targets of 22 miRNAs were primarily enriched in mitogen-activated protein kinase, platelet derived growth factor, vascular endothelial growth factor, epidermal growth factor receptor, and p53 signaling. In particular, in the functional assessment of miRNAmRNA interactions, RAS pathways, including downstream pathways (PI3K-AKT-mTOR and RAS-RAF-MEK-ERK), were determined to be enriched. @*Conclusion@#Circulating miRNAs in bile-derived exosomes provide new information for the development of miRNA analysis in CCA. These miRNAs may represent the oncogenic characteristics of CCA tissue, enabling them to be used instead of tissue samples for the diagnosis of CCA. Further research investigating circulating miRNAs in bile exosomes may lead to more rational, targeted approaches to treatment.

Discovery of a New DNA Gyrase A Inhibitor, 4-(1-methyl-6-nitroquinolin-1-ium-4-yl)amino-N-4-(1-methylpyridin-1-ium-4-yl)aminophenylbenzamide

Escherichia coli (E. coli) is a clinically important causative organism that can lead to urinary tract infections. Quinolone antibiotics are among the first-line treatments for urinary tract infections. However, the frequency of resistance to quinolone in E. coli has been increasing. Therefore, new antimicrobial agents that can be used for treatment in lieu of quinolone antibiotics are needed. In this study, thirty-six compounds with higher scores in a virtual screening based on the three-dimensional structure of E. coli DNA gyrase were selected for in vitro antimicrobial activity testing. An in vitro test confirmed the antimicrobial activity of 4-[(1-methyl-6-nitroquinolin-1-ium-4-yl)amino]-N-[4-[(1-methylpyridin-1-ium-4-yl)amino]phenyl]benzamide (ZINC18057104) against E. coli among the 36 compounds. The minimum inhibitory concentration (MIC) of ZINC18057104 against E. coli ATCC® 25922™ was 2 μg/ml, and the MIC₅₀ and MIC₉₀ for the 72 quinolone-resistant E. coli clinical isolates were 4 and 64 μg/ml, respectively. ZINC18057104, which has a quinoline structure which is similar to the quinolone antibiotics, is predicted to exhibit antimicrobial activity in quinolone-resistant E. coli because it has different molecular interactions with the DNA gyrase than that of existing quinolone antibiotics.

Sonication Induces Apoptosis in HL-60 Cells / 계명의대학술지

To investigate a specific mechanism of apoptosis induced by sonication, we applied 20 kHz ultrasound to leukemia cell line HL-60 with different intensities (0-60 W/cm2) and time durations (0-100 sec). In accordance with previous reports, ultrasound treatment in HL-60 cells induced immediate cell death and delayed cell death which are associated with cell lysis and apoptosis, respectively. Delayed cell death of HL-60 was also detected 5 hours after sonication in our experiment. Detection of caspase activation by Western blot and sub-G1 accumulation by flow cytometry confirmed that apoptosis plays a role in delayed cell death induced by sonication in HL-60 cells. In addition, we found that decrease in lysosomes of HL-60 cells after sonication suggesting lysosomal rupture is involved in the mechanism of cell death induced by sonication.

Genome-Wide Association Study of Medication Adherence in Chronic Diseases in the Korean Population

Medication adherence is generally defined as the extent of voluntary cooperation of a patient in taking medicine as prescribed. Adherence to long-term treatment with chronic disease is essential for reducing disease comorbidity and mortality. However, medication non-adherence in chronic disease averages 50%. This study was conducted a genome-wide association study to identify the genetic basis of medication adherence. A total of 235 medication non-adherents and 1,067 medication adherents with hypertension or diabetes were used from the Korean Association Resource project data according to the self-reported treatment status of each chronic disease, respectively. We identified four single nucleotide polymorphisms with suggestive genome-wide association. The most significant single nucleotide polymorphism was rs6978712 (chromosome 7, p = 4.87 x 10-7), which is located proximal to the GCC1 gene, which was previously implicated in decision-making capability in drug abusers. Two suggestive single nucleotide polymorphisms were in strong linkage disequilibrium (r2 > 0.8) with rs6978712. Thus, in the aspect of decision-making in adherence behavior, the association between medication adherence and three loci proximal to the GCC1 gene seems worthy of further research. However, to overcome a few limitations in this study, defining the standardized phenotype criteria for self-reported adherence should be performed before replicating association studies.

Microbial Profile of the Stomach: Comparison between Normal Mucosa and Cancer Tissue in the Same Patient

Gastric cancer is the third most common cancer and the third most frequent cause of cancer mortality in Asia. It is predicted that gastric cancer will remain an important cause of death at least during the next half century because of the increasing number of new cases in an aging population. However, little has been revealed about the role of gastric microbes and their reaction to gastric cancer. In this study, we identified differences in the microbial communities between gastric cancer and normal gastric mucosa by comparing the microbiomes of tissues from the same patients. The clustering analysis results showed different bacterial communities between normal gastric mucosa and gastric cancer. A comparison of bacterial communities at the species level revealed that Helicobacter pylori was significantly reduced in cancer tissue compared to that in normal gastric mucosa in the same patient. A comparison at the genus level showed that Propionibacterium spp., Staphylococcus spp., and Corynebacterium spp. had significantly reduced populations in cancer tissue, whereas Clostridium spp. and Prevotella spp. had significantly increased populations in cancer tissue.

Apoptosis and upregulation of TNF-alpha and TRAIL receptor 1 (DR4) in the pathogenesis of food protein-induced enterocolitis syndrome / 소아과

PURPOSE: Expression levels of tumor necrosis factor (TNF)-alpha expression on the mucosa of the small intestine is increased in patients with villous atrophy in food protein-induced enterocolitis syndrome (FPIES). TNF-alpha has been reported to induce apoptotic cell death in the epithelial cells. We studied the TNF family and TNF-receptor family apoptosis on the duodenal mucosa to investigate their roles in the pathogenesis of FPIES. METHODS: Fifteen infants diagnosed as having FPIES using standard oral challenge test and 5 controls were included. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining was performed to identify the apoptotic cell death bodies. Immunohistochemical staining of TNF-alpha, Fas ligand (FasL) for TNF family and TNF-related apoptosis-including ligand (TRAIL) receptor 1 (DR4), TRAIL receptor 2 (DR5), and Fas for TNF-receptor family were performed to determine the apoptotic mechanisms. RESULTS: TUNEL+ was significantly more highly expressed in the duodenal mucosa of FPIES patients than in controls (P=0.043). TNF-alpha (P=0.0001) and DR4 (P=0.003) were significantly more highly expressed in FPIES patients than in controls. Expression levels of FasL, Fas, and DR5 were low in both groups and were not significantly different between the 2 groups. CONCLUSION: These results suggest that FPIES pathogenesis is induced by apoptosis, and that TNF-alpha expression and DR4 pathway may have an important role in apoptosis.

The Significance of Gastric Juice Analysis for a Positive Challenge by a Standard Oral Challenge Test in Typical Cow's Milk Protein-Induced Enterocolitis

This study was performed to investigate the significance of gastric juice analysis (GJA) as a diagnostic criterion of a positive challenge in a standard oral cow's milk challenge (OCC) to confirm typical cow's milk protein-induced enterocolitis (CMPIE). Data from 16 CMPIE patients (aged 14 to 44 days) were analyzed. A standard OCC was openly executed using 0.15 g/kg of protein. Three symptoms (vomiting, lethargy, and bloody or pus-like stool), and four laboratory findings (GJA [3 hr], changes in peripheral blood absolute neutrophil count [ANC] [6 hr], C-reactive protein [6 hr], and stool smear test for occult blood or leukocytes) were observed after OCC. Before OCC, baseline studies were conducted; a stool smear test, blood sampling, and GJA. Positive OCC results were; vomiting (87.5%) (observed 1-3 hr after OCC), lethargy (62.5%) (1-3 hr), bloody or pus-like stool (43.8%) (6-10 hr), abnormal GJA (93.8%), an ANC rise >3,500 cells/microliter (93.8%), and an abnormal stool smear test (75.0%). A single GJA test after a standard OCC is a sensitive diagnostic criterion of a positive challenge, and may provide an early confirmatory diagnosis of CMPIE. An investigation of positive OCC outcomes helps to find out a diagnostic algorithm of criteria of a positive challenge in CMPIE.

Advanced Criteria for Clinicopathological Diagnosis of Food Protein-induced Proctocolitis

The clinicopathological findings in previous studies concerning food protein-induced proctocolitis (FPIPC) are quite diverse in terms of results and conclusions. The aim of this study was to suggest advanced clinicopathological diagnostic criteria that facilitate the early confirmation of FPIPC. Data of 38 FPIPC patients, who had received sigmoidoscopy and biopsy, was analyzed. Microscopic findings were compared with observations of previous studies. Feeding at onset of bleeding was exclusively breast-fed (94.7%) and formula-fed or mixed-fed (5.3%). Endoscopic abnormalities were observed in all patients; nodular hyperplasias with circumscribed and/or central pit-like erosions in 94.7% and erythema in 5.3%. Histopathological findings were; lymphoid aggregates in 94.7%, eosinophils in lamina propria of > or =60 cells/10 HPF in 97.4% and of >20 cells/HPF in 63.2%, epithelial or muscularis mucosa eosinophil infiltration in 97.4%, and crypt abscess in 2.6%. The majority of FPIPC patients are exclusively breast-fed and nodular hyperplasias with erosions may be a disease specific endoscopic finding. Histologic diagnosis of FPIPC is compatible with eosinophils in the lamina propria of > or =60 cells/10 high power fields; however, >20 cells/HPF is not an appropriate diagnostic criterion.

Indexes of Suspicion of Typical Cow's Milk Protein-Induced Enterocolitis

This study was performed to identify clinical factors that facilitate the diagnosis of typical cow's milk protein-induced enterocolitis (CMPIE). Data from 142 consecutive patients (aged 15 to 45 days, cow's milk formula- or cow's milk and breast milk mixed-fed) admitted due to vomiting and/or diarrhea were retrospectively analyzed. These 142 subjects were divided into three groups: the CMPIE, infection, and non-infection group. Each group was composed of 16 (11.3%), 102 (71.8%), and 24 (16.9%) patients, respectively. On admission, poor weight gain (p=0.003), hypoalbuminemia (p=0.035), peripheral leukocytosis (p=0.012), and metabolic acidosis (p=0.015) were found to be more significant in the CMPIE group than those in other two groups. In CMPIE, serum albumin levels decreased from 3.3+/-0.9 g/dL on admission to 2.6+/-0.3 g/dL during admission (p<0.05), and methemoglobinemia was observed in 3 patients (18.8%) (p=0.012). Multiple logistic regression analysis showed that the independent predictors of CMPIE versus the infection group were failure to gain weight (OR, 10.75 [95% CI, 1.53-66.12]) (p= 0.014) and hypoalbuminemia (OR, 9.53 [95% CI, 1.62-49.01]) (p=0.010). The early recognition of indexes of suspicion for CMPIE may be of help in the diagnosis and treatment of this disorder.

Curcumin inhibits the expression of COX-2 in UVB-irradiated human keratinocytes (HaCaT) by inhibiting activation of AP-1: p38 MAP kinase and JNK as potential upstream targets

Ultraviolet B (UVB) irradiation of skin induces an acute inflammation. Cyclooxygenase-2 (COX-2) protein plays key roles in acute inflammation in UVB-irradiated keratinocyte cell line HaCaT. Recently, curcumin has been regarded as a promising anti-inflammatory agent due to its ability to inhibit COX-2 expression. However, it remains largely unknown whether curcumin inhibits the UVB-induced COX-2 expression in HaCaT cells. This study was undertaken to clarify the effect of curcumin on the expression of COX-2 in UVB- irradiated HaCaT cells and further determined the molecular mechanisms associated with this process. In this study, we have found that the expression of COX-2 mRNA and protein were up-regulated in UVB-irradiated HaCaT cells in a dose- and time-dependent manner. Interestingly, treatment with curcumin strongly inhibited COX-2 mRNA and protein expressions in UVB-irradiated HaCaT cells. Notably, there was effective inhibition by curcumin on UVB-induced activations of p38 MAPK and JNK in HaCaT cells. The DNA binding activity of AP-1 transcription factor was also markedly decreased with curcumin treatment in UVB-irradiated HaCaT cells. These results collectively suggest that curcumin may inhibit COX- 2 expression by suppressing p38 MAPK and JNK activities in UVB-irradiated HaCaT cells. We propose that curcumin may be applied as an effective and novel sunscreen drug for the protection of photoinflammation.

Expression of Human beta-defensin 2 mRNA by Lipopolysaccharide in Human Corneal Epithelial Cells

Recently the transcriptional up-regulation of human beta-defensin 2 (HBD-2) by lipopolysaccharide (LPS) was found to be associated with NF-kappaB binding site. Although the general mechanisms of NF-kappaB activation by LPS stimulation are well understood, less is known about the signal transduction pathway leading to LPS-induced NF-kappaB activation in human corneal epithelial (HCE) cells. The aim of this study was to investigate the intracellular signals involved in LPS-induced HBD-2 mRNA expression in HCE cells. Pretreatments of inhibitors for NF-kappaB, protein tyrosine kinase, p38 mitogen activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) attenuated the LPS-induced NF-kappaB DNA binding activity and HBD-2 mRNA expression. Furthermore, pretreatments with inhibitors for protein kinase C (PKC), phosphatidylcholine-phospholipase C, phosphatidylinositol-phospholipase C, or phosphatidate phosphohydrolase prevented LPS-induced HBD-2 mRNA expression and HBD-2 prmoter-driven luciferase activity. However, the increased expression of HBD-2 mRNA and the increased DNA binding activity of NF-kappaB induced by LPS were not changed by the blockage of extracellular signal-regulated kinase (ERK) and of addition of antioxidants. Forskolin, a protein kinase A (PKA) agonist did not induce HBD-2 mRNA expression. These data demonstrate that LPS-induced HBD-2 mRNA expression via NF-kappaB is, at least in part, dependent on PKC, p38 MAPK, JNK, and protein tyrosine kinase status, but appears to be independent on PKA, ERK and ROS in HCE cells. Taken together, there may be more than one signaling pathways that lead to LPS-induced up-regulation of HBD-2 mRNA expression in HCE cells.

Antibacterial Effect of Lidocaine in Mouse Model of Acute Rhinosinusitis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: This study was performed to verify the antibacterial effect of lidocaine against common bacterial pathogens which causes acute bacterial rhinosinusitis in vitro, and also to evaluate in vivo effects in the nasal cavity of mice with an acute rhinosinusitis induced by Streptococcus pneumoniae inoculation. MATERIALS AND METHOD: The initial cultures of Streptococcus pneumonia, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Hemophilus influenza were done in Mueller-Hinton broth and the subsequent culture in 5% sheep blood agar (SBA). Minimal inhibitory concentration (MIC) was obtained by making culture broth to a turbidity of McFarland No 0.5 overnight by having it diluted by 1:200 times, and medicating 100 microL lidocaine in each culture. It was cultured for 24 hours at 36degrees C and analyzed spectrophotometrically. Minimal bactericidal concentration (MBC) was obtained by the same work as MIC and was followed by the subculture in 5% SBA to obtain the minimum concentration of no growth. Two percent concentration of lidocaine, MBC of S. pneumoniae was used for in vivo study. Thirty-six experimental mice (C57BL6/J) were divided: the control Group I contained only broth inoculation, Group II S. pneumoniae inculation and Group III to VI varying concentrations of lidocaine inoculation in different intervals and exposure time. On the 6th day, nasal lavage was done and mucosal neutrophil count was sought by dissecting the mice head by selecting three sections of anatomicallynd same site and 4 randomly selected places from each section. RESULTS: MIC and MBC values of S. pneumoniae were 1%, 2%, K. pneumoniae 2% and 2%, P. aerusinosa 2% and 4%, S. aureus 2% and 4%, H. influenzae 0.25%, and 1%, respectively. Mucosal neutorophils revealed a more statistically significant increase in Group II than all other groups followed by Group V, VI, III, and IV. The nasal lavage showed larger colony count in Group II, III, and V than those of other groups without any statistical meaning. CONCLUSION: This study enabled us to find out the MIC and MBC of lidocaine on various pathogens, the causes of an acute rhinosinusitis in vitro. It also showed that an acute rhinosinusitis is developed by using S. pneumoniae in vitro and that the longer the exposure time and higher the exposure frequency of lidocaine, the greater were antibacterial effects.

Expressional Regulation of Cancer Metastasis Related Gene, MMP-9, by Resveratrol

Proteolytic degradation of the extracellular matrix and tumor metastasis correlate with the expression of endopeptidases known as matrix metalloproteinases (MMPs). Expression of MMPs is regulated by cytokines and signal transduction pathways including those activated by phorbol myristate acetate (PMA). We found that resveratrol, a phytoalexin present in grapes, significantly inhibits the PMA-induced increase of MMP-9 expression and activity. These effects of resveratrol were dose-dependent and correlated with the suppression of MMP-9 mRNA expression levels. PMA caused a 23-fold increase in MMP-9 promoter activity, which was suppressed by resveratrol. Transient transfection by MMP-9 constructs, in which specific transcriptional factors were mutagenized, indicated that the effects of PMA and resveratrol were mediated via AP1 and NFkB response elements. Resveratrol inhibited PMA-mediated activation of c-Jun Nterminal kinase (JNK) and protein kinase C (PKC)-delta activation. Therefore, we conclude that the inhibitory activities of resveratrol on MMP-9, JNK, and PKC-delta may have therapeutic potential for controlling growth and invasiveness of tumors.

Melatonin reduces ultraviolet-B induced cell damages and polyamine levels in human skin fibroblasts in culture

UV radiation is known to cause photoaging of the skin and is considered one of the leading cause of developing skin carcinogenesis. Melatonin which has a highly lipophilic molecular structure facilitating penetration of cell membranes and serving as an extra- and intracellular free radical scavenger has been demonstrated to protect photodamage of skin affected by UV exposure. In this study, we have examined the role of melatonin in response to UVB induced photodamaging process, using human skin fibroblasts in vitro. Cell survival curves after UVB irradiation showed dose-dependent decrease. Only 60% of fibroblasts were survived at 140 mJ/cm2 UVB irradiation. By pre-cultivation of cells with melatonin (100 nM), a significant number of cells remained unaffected. After UVB irradiation with 70 mJ/cm2, the level of putrescine was 1.7+/-0.3 fold increased compared to melatonin pre-treated group. In Northern analyses, the transcriptional level of ornithine decarboxylase (ODC) gene expression was increased by UVB irradiation and prohibited by melatonin. These results indicated that melatonin was effectively able to neutralize membrane peroxidation when present in relevant concentration during UVB irradiation and diminishes the UVB-induced increase of polyamine synthesis and ODC gene expression. Collectively, ODC response to UVB induced changes are possibly involves a melatonin or antioxidant sensitive regulatory pathway in normal human skin fibroblast.

Expression of Survivin and HIAP-1 in Korean Gastric Cancers

PURPOSE: Dysregulation of apoptosis may attribute to development of cancer by abnormally prolonging cell viability with accumulation of transforming mutations. Survivin and HIAP (Human Inhibitors of Apoptosis)-1 were recently described as apoptosis inhibitors. Their pathogenic roles in gastric cancer are largely unknown. In the present study, we examined the expression of survivin and HIAP-1 in gastric cancer tissues and cell lines in order to elucidate the roles of survivin and HIAP-1 in the process of gastric carcinogenesis. MATENRIALS AND METHODS: Eight gastric cancer cell lines and five gastric cancer tissues were studied. The expression of survivin and HIAP-1 were evaluated by reverse transcription -polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot. RESULTS: Western blot and RT-PCR analysis revealed survivin and HIAP-1 expression in all gastric cancer cell lines. Increased expression of survivin and HIAP-1 were found in all cases of gastric cancer tissues compared to normal tissues by Western blot analysis. In immunohistochemical analysis tumor cells were stained with anti-survivin and anti-HIAP-1 antibodies. Cell cycle dependence of survivin expression was preserved in gastric cancer cell lines. CONCLUSION: The results indicate that increased expression of survivin and HIAP-1 genes may play an important role in gastric cancer.

Alterations of 9p21-22 Region Encoding Genes in Primary Glioblastomas

BACKGROUND: Glioblastomas are one of the most common and aggressive malignant glial tumors occuring in the central nervous system. This study analyzed the status of p15INK4b, p14ARF, p16INK4a, MTAP, IFNA, and IFNB genes in 36 primary glioblastomas to investigate whether the inactivation of these genes participate in primary glioblastoma tumorigenesis. METHODS: We used polymerase chain reaction, polymerase chain reaction/single strand conformational polymorphism (PCR/SSCP) analysis, and methylation-specific PCR. RESULTS: Homozygous deletions at the p16INK4a gene were detected in 11 cases (30.5%) of 36 primary glioblastomas, and the promoter hypermethylation was found in 3 cases (8.3%) of 36 primary glioblastomas. In mutational analysis for the p16INK4a gene by PCR/SSCP, there was no abnormal mobility-shifted band in 36 cases of primary glioblastomas. The overall frequency of p16INK4a alterations including homozygous deletion and promoter hypermethylation in 36 primary glioblastomas was 38.8% (14 of 36). Deletions of p15INK4b were noted in 4 cases (11.1%), whereas deletions of the p14ARF and MTAP genes were detected in 1 case of 36 cases of primary glioblastomas. But deletions of the INFA and B genes were not found. CONCLUSIONS: These results suggest that alterations of the p16INK4a gene can be important mechanisms of the tumorigenesis of primary glioblastomas, and the p16INK4a gene is inactivated by mechanisms including homozygous deletion and promoter hypermethylation.

Effect of Melatonin on Hemolysis Induced by Cyclosporine / 대한신장학회잡지

Hemolysis is one of the side effects of cyclosporine(CsA). Some experimental and clinical data have strongly suggested that CsA-induced hemolysis is resulted from the increased production of free radical species by CsA. Melatonin, a pineal secretory product, acts as a highly efficient free radical scavenger. Thus, melatonin may have a protective effect on the CsA-induced hemolysis. To test this hypothesis, the final concentration of 4.2x106/mL with human erythrocytes was incubated in test tube at 37 degrees C water bath with 1.67 mg/mL of CsA and 72 nmol/mL of melatonin. The degree of hemolysis and the amount of malondialdehyde which gives an indirect index of oxidative injury were measured in group 1 containing only isotonic buffer solution, in group 2 containing only CsA, and in group 3 containing both CsA and melatonin. The degrees of hemolysis in group 2 were higher than those of group 1. The degrees of hemolysis in group 3 were higher than those of group 1, and lower than those of group 2. The amounts of malondialdehyde in group 2 were higher than those of group 1. The amounts of malondialdehyde in group 3 were higher than those of group 1, and lower than those of group 2. These results indicate that the direct contact of erythrocytes with CsA results in free radical mediated hemolysis and the hemolysis by CsA can be prevented with melatonin.

The Levels of MDM2 Protein Are Decreased by a Proteasome-Mediated Proteolysis Prior to Caspase-3-Dependent pRb and PARP Cleavages

MDM2 is a substrate of caspase-3 in p53-mediated apoptosis. In addition, MDM2 mediates its own ubiquitination in a RING finger-dependent manner. Thus, we investigated whether MDM2 is degraded through a ubiquitin-dependent proteasome pathway in the absence of p53. When HL-60 cells, p53 null, were treated with etoposide, MDM2 was markedly decreased prior to caspase-3-dependent retinoblastoma tumor suppressor protein (pRb) and poly (ADP- ribose) polymerase (PARP) cleavages. Moreover, down-regulation of MDM2 level was not coupled with its mRNA down-regulation. However, the level of MDM2 was partially restored by proteasome inhibitors such as LLnL and lactacystin, even in the presence of etoposide. Our results suggest that, in the p53 null status, MDM2 protein level is decreased by proteasome-mediated proteolysis prior to caspase-3-dependent PARP and pRb cleavages.