Inhibitory effects of orobol 7-O-D-glucoside from banaba (Lagerstroemia speciosa L.) on human rhinoviruses replication

AIMS

The anti-human rhinovirus (HRV) activity of orobol 7-O-d-glucoside (O7G) from Lagerstroemia speciosa L. (Lythraceae) was evaluated in Hela cells.

METHODS AND RESULTS

We tested anti-HRV activity of O7G using a cytopathic effect (CPE) reduction method, which exhibited broad-spectrum anti-HRVs activity with a 50% inhibitory concentration (IC(50)) ranging from 0.58 to 8.80 microg ml(-1). The 50% cytotoxicity concentration (CC(50)) of O7G is more than 100 microg ml(-1), and the derived therapeutic indices are more than 12. Ribavirin didn't possess antiviral activity against HRV15, HRV3 and HRV5, but exhibited weak antiviral activity against HRV2 and HRV3, and showed strong anti-HRV6 and -14 activities.

CONCLUSIONS

These results suggest that O7G is a novel drug class with broad spectrum antiviral activity against HRV species A (HRV1B, HRV2, HRV15 and HRV40) and species B (HRV3, HRV6 and HRV14), as well as pleconaril-resistant virus (HRV5).

SIGNIFICANCE AND IMPACT OF THE STUDY

Therefore, these findings provide important information for the utilization of Q7G promising broad spectrum for human rhinovirus treatment.

Sewage sludge reduction and system optimization in a catalytic ozonation process

The main objective of this study was to suggest a feasible, effective process for the reduction of sewage sludge using ozone oxidation catalysed by metal ion. A series of lab-scale experiments was conducted to select a suitable catalyst and its proper dose to achieve optimum sludge reduction. Using a central composite design under response surface methodology (RSM), system optimization with respect to sludge reduction and cost-effectiveness was performed by varying the independent parameters: dosages of ozone and ions. Five metal ions, Mn2+, Fe2+, Zn2+, CU2+, and Al3+1, were tested, and the manganese ion showed the highest sludge reduction, as measured by a decrease in total suspended solids. The ozone/Mn combination achieved approximately twice as much sludge reduction as the ozonation alone. Furthermore, the Mn dose of 10 mg/g-TS (total solids) resulted in the highest sludge reduction efficiency among the different doses, which ranged from 0 to 20 mg-Mn/g-TS. The predicted efficiency of sewage sludge reduction using the RSM was found to agree well with the experimental results, and the statistical analyses predicted optimum ranges for the doses of ozone and Mn ions, taking into account the overall cost for sewage sludge treatment.

Phosphorus doped Zn(1-x)Mg(x)O nanowire arrays

We demonstrate the growth of phosphorus doped Zn(1-x)Mg(x)O nanowire (NW) using pulsed laser deposition. For the first time, p-type Zn(0.92)Mg(0.08)O:P NWs are likely obtained in reference to atomic force microscopy based piezoelectric output measurements, X-ray photoelectron spectroscopy, and the transport property between the NWs and a n-type ZnO film. A shallow acceptor level of approximately 140 meV is identified by temperature-dependent photoluminescence. A piezoelectric output of 60 mV on average has been received using the doped NWs. Besides a control on NW aspect ratio and density, band gap engineering has also been achieved by alloying with Mg to a content of x = 0.23. The alloyed NWs with controllable conductivity type have potential application in high-efficiency all-ZnO NWs based LED, high-output ZnO nanogenerator, and other optical or electrical devices.

Identifying individual n- and p-type ZnO nanowires by the output voltage sign of piezoelectric nanogenerator

Based on a comparative study between the piezoelectric outputs of n-type nanowires (NWs) and n-core/p-shell NWs along with the previous study (Lu et al 2009 Nano. Lett. 9 1223), we demonstrate a one-step technique for identifying the conductivity type of individual ZnO nanowires (NWs) based on the output of a piezoelectric nanogenerator without destroying the sample. A negative piezoelectric output voltage indicates an NW is n-type and it appears after the tip scans across the center of the NW, while a positive output voltage reveals p-type conductivity and it appears before the tip scans across the central line of the NW. This atomic force microscopy based technique is reliable for statistically mapping the majority carrier type in ZnO NWs arrays. The technique may also be applied to other wurtzite semiconductors, such as GaN, CdS and ZnS.

Biodegradable and compostable alternatives to conventional plastics

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all 'good' or petrochemical-based products are all 'bad'. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated 'home' composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted.

The Glu346Lys polymorphism and frameshift mutations of the Methyl-CpG Binding Domain 4 gene in gastrointestinal cancer

MBD4 (Methyl-CpG Binding Domain 4) is a human DNA repair protein that may be involved in DNA mismatch repair. The polymorphisms and frameshift mutations in MBD4 may influence cancer susceptibility and the development of cancer. The specific aim of this study was to investigate whether frameshift mutations of the MBD4 gene and the codon 346 polymorphism were associated with microsatellite instability (MSI) and the risk for gastrointestinal cancer. We examined the MSI, frameshift mutations and polymorphisms of the MBD4 gene in 84 patients with gastric cancers, 82 colorectal cancers and 299 healthy controls. MSI was found in 19 (22.6%) and 26 (31.7%) of the gastric and colorectal cancer samples, respectively. The mutation analysis revealed no frameshift mutations in the MBD4 gene among the gastrointestinal cancers. The frequencies of genotypes: Glu/Glu, Glu/Lys and Lys/Lys were 41.7% (35/84), 41.7% (35/84) and 16.6% (14/84), respectively, in the gastric cancer cases, and 42.7% (35/82), 36.6% (30/82) and 20.7% (17/82), respectively, in the colorectal cancers. MSI was not associated with the MBD4 codon 346 polymorphism and there was no significant difference in the frequency of the genotypes between healthy controls and gastric cancer patients (P=0.2748). However, the MBD4 codon 346 polymorphism was significantly associated with the risk of colorectal cancer (P=0.0315). Our findings suggest that microsatellite instability may not be associated with frameshift mutations in the MBD4 gene, and that the MBD4 codon 346 polymorphism may play arole in colorectal cancer susceptibility in the Korean population.

Low frequency mutation of the Ephrin receptor A3 gene in hepatocellular carcinoma

EphA3 is a component of the Eph/ephrin tyrosine kinase system, which participates in vasculature development. This receptor/ligand system is associated with various signaling pathways related to cell growth and viability, cytoskeletal organization, cell migration, and anti-apoptosis. Accumulated evidence suggests that aberrant regulation of EphA3 and its genetic alterations are implicated in the development and progression of various cancers. However, despite a high incidence of EphA3 over-expression, no such investigation has been performed in hepatocellular carcinoma. Thus, we investigated genetic alterations of the EphA3 gene in 73 cases of hepatocellular carcinoma by single-strand conformational polymorphism and sequencing. One novel D219V missense mutation was found in the extracellular domain of EphA3, and two genetic alterations in the intracellular sterile-alpha-motif (SAM) domain of EphA3 appeared to be polymorphisms. Although the functional assessments of this mutant are incomplete, it is believed that this novel EphA3 mutation may contribute to the development of hepatocellular carcinoma.

The p53 codon 72 polymorphism and susceptibility to colorectal cancer in Korean patients

TP53 is a major gene involved in the determination of proliferation or growth arrest at the cellular level. The polymorphism of p53 at codon 72 has been widely studied; this variation has been associated with cancer susceptibility and disease outcome. The specific aim of this study was to investigate whether the p53 codon 72 polymorphism is associated with individual susceptibility to colorectal cancer in Korean patients. The frequency of the polymorphism was examined in 156 patients with colorectal cancer and in 293 healthy controls. The polymorphism analysis was performed by amplifying exon 4 of p53 and digesting the products with restriction enzyme. The frequencies of genotypes: Arg/Arg, Arg/Pro and Pro/Pro were 34.6% (54/156), 43.0% (67/156) and 22.4% (35/156), respectively, in the cases with colorectal cancer, and 28.9% (114/293), 47.8% (140/293) and 13.3% (39/293), respectively, in the healthy controls. Statistically, there was a significant difference in the frequency of the genotypes when the healthy controls were compared to the patients with colorectal cancer (<em>p</em>=0.0459). The specific allele frequencies showed borderline significance (<em>p</em>=0.0502). Our findings suggest that the p53 Pro72 variant is associated with an increased risk for colorectal cancer in the Korean population.

KEYWORDS

p53, colorectal cancer, polymorphism, susceptibility, metastasis.

Overexpression of Wnt-2 in colorectal cancers

The binding of the Wnt ligand to its receptor Frizzled, activates the Wnt canonical signaling pathway in carcinogenesis as well as many cellular processes, including cellular proliferation and differentiation. Wnt-2, one of 19 members of the <em>Wnt</em> gene family, is frequently overexpressed in malignant tissues. Here, in order to investigate the role of Wnt-2 in colorectal carcinogenesis, we examined the expression of the Wnt-2 protein in 120 colorectal cancers by immunohistochemistry. Wnt-2 protein was expressed in the cell membrane and cytoplasm and up-regulated in 74 (61.7%) of 120 colorectal cancers. Statistically, overexpression of Wnt-2 protein was not associated with the clinical and pathological parameters studied, including tumor location, tumor size, clinical stage, lymph node metastasis, and 5-year survival (<em>P > </em>0.05). These results indicate that up-regulation of the Wnt-2 protein might play a role in the development of colorectal cancers, as an early event of carcinogenesis.

KEYWORDS

Wnt-2 protein, expression, immunohistochemistry, tissue microarray, colon cancer.

Antiviral activity of raoulic acid from Raoulia australis against Picornaviruses

RNA viruses are a major source of respiratory diseases worldwide. The lack of effective therapeutical treatment underlines the importance of research for new antiviral compounds. Raoulic acid is a principal ingredient of the plant Raoulia australis Hook. F. Antiviral assay using cytopathic effect (CPE) reduction method showed that raoulic acid possessed strong antiviral activity against human rhinovirus 2 (HRV2) with a 50% inhibition concentration (IC(50)) value of less than 0.1mug/ml, human rhinovirus 3 (HRV3) with a IC(50) value of 0.19 microg/ml, coxsackie B3 (CB3) virus with IC(50) values of 0.33 microg/ml, coxsackie B4 (CB4) virus with IC(50) values of 0.40 microg/ml, and enterovirus 71 (EV71) virus with IC(50) values of less than 0.1 microg/ml. However, the compound did not possess antiviral activity against influenza A (Flu A/PR, Flu A/WS, H1N1) and B viruses at four concentrations ranging from 0.1 to 100 microg/ml.

Enhanced bio-energy recovery in a two-stage hydrogen/methane fermentation process

A two-stage hydrogen/methane fermentation process has emerged as a feasible engineering system to recover bio-energy from wastewater. Hydrogen-producing bacteria (HPB) generate hydrogen from readily available carbohydrates, and organic acids produced during the hydrogen fermentation step can be degraded to generate methane in the following step. Three strong acids, HCl, H(2)SO(4), and HNO(3), were tested to determine the appropriate pre-treatment method for enhanced hydrogen production. The hydrogen production rates of 230, 290, and 20 L/kg(-glucose)/day was observed for the sludge treated with HCl, H(2)SO(4), and HNO(3), respectively, indicating that the acid pre-treatment using either HCl or H(2)SO(4) resulted in a significant increase in hydrogen production. The fluorescent in situ hybridization method indicated that the acid pre-treatment selectively enriched HPB including Clostridium sp. of cluster I from inoculum sludge. After hydrogen fermentation was terminated, the sludge was introduced to a methane fermentation reactor. This experiment showed methane production rates of 100, 30, and 13 L/kg(-glucose)/day for the sludge pre-treated with HCl, H(2)SO(4), and HNO(3), respectively, implying that both sulfate and nitrate inhibited the activity of methane-producing bacteria. Consequently, the acid pre-treatment might be a feasible option to enhance biogas recovery in the two-stage fermentation process, and HCl was selected as the optimal strong acid for the enrichment of HPB and the continuous production of methane.

Neurosurgical aspects of sedimentation levels in acute intracerebral haematoma

We describe the neurosurgical aspects of sedimentation levels that are rarely found in acute intracerebral haematomas (ICH). We had four patients with acute ICH whose cerebral computed tomography revealed sedimentation levels. Two patients had received thrombolytic therapy for ischaemic heart disease and one for ischaemic stroke. Another patient, who was diagnosed later as having a coagulation disorder, did not have any medical history on admission. All patients had emergency ICH drainage under local anaesthesia. In the immediate postoperative period, we observed dramatic improvement in all the patients, without surgical complications. The sedimentation level in an ICH should be identified as a specific indicator of a coagulation defect and a thorough search for possible underlying coagulopathy is warranted. We believe that simple ICH drainage should be performed as the haematoma is in a liquid form.

Down-regulation of ATBF1 is a major inactivating mechanism in hepatocellular carcinoma

AIMS

alpha-Fetoprotein (AFP) is frequently detected in hepatocellular carcinomas (HCCs) and AT motif binding factor 1 (ATBF1) down-regulates AFP gene expression in hepatic cells. The ATBF1 gene also inhibits cell growth and differentiation, and altered gene expression is associated with malignant transformation. The aim was to investigate the potential role of the ATBF1 gene in HCCs.

METHODS AND RESULTS

Somatic mutations, allelic loss and hypermethylation of the ATBF1 gene were analysed in 76 sporadic HCCs. The level of ATBF-1 mRNA expression was analysed using quantitative real-time reverse transcriptase-polymerase chain reaction. Genetic studies of the ATBF1 gene revealed absence of somatic mutation in the hotspot region and 15 (25%) of 60 informative cases showed allelic loss at the ATBF1 locus. Hypermethylation in the intron 1 region of the ATBF1 gene was detected in only one case. Interestingly, ATBF1 mRNA expression in HCCs was significantly reduced in 55 (72.4%) samples compared with the corresponding surrounding liver tissues. Reduced expression was not statistically associated with clinicopathological parameters including stage, histological grade, infective virus type, and serum alpha-fetoprotein level.

CONCLUSIONS

The ATBF1 gene may contribute to the development of HCCs via transcriptional down-regulation of mRNA expression, but not by genetic or epigenetic alterations.

No association of MDM2 T309G polymorphism with susceptibility to Korean gastric cancer patients

Mouse double minute 2 (Mdm2) acts as a negative regulator of p53 by binding to the amino-terminus of p53. The common T309G polymorphism of Mdm2 has been the most frequently investigated, which can influence in cancer susceptibility and disease outcome. The specific aim of this study is to investigate whether the T309G polymorphism of Mdm2 was associated with individual susceptibility to gastric cancer in Korea. The frequency of the polymorphism was examined in 239 gastric cancer patients and 299 healthy controls. Polymorphism analysis was performed by amplifying the first intron of the Mdm2 and digesting with restriction enzyme and sequencing the products. The frequencies of genotypes: T/T, T/G and G/G were 26.8% (64/239), 46.0% (110/239) and 27.2% (65/239), respectively, in gastric cancer cases and 20.4% (61/299), 50.8% (152/ 299) and 28.8% (86/299), respectively, in healthy controls. Statistically, there was no significant difference in the frequency of genotype and allele between healthy control and gastric cancer patients. Finally, the polymorphism was not associated with increased risk of gastric cancer in this population. When stratified by histological subtype of gastric cancer, the risk was also not statistically significant. Our findings suggested that the T309G polymorphism of Mdm2 was not associated with an increased risk for gastric cancer in Korean population.

KLF6 IVS1 -27G/A polymorphism with susceptibility to gastric cancers in Korean

KLF6 is a key cell cycle regulator that is downregulated in several kinds of human cancers, including gastric cancer. The IVS1 -27G/A polymorphism of KLF6 has been investigated, which can influence susceptibility to gastric cancer and disease outcome. In order to investigate whether the IVS1 -27G/A polymorphism of KLF6 is associated with individual susceptibility to gastric cancer in Korea, the frequency of the polymorphism was examined in 264 gastric cancer patients and 299 healthy controls. Single nucleotide polymorphism (SNP) analysis was performed by amplifying intron 1 of KLF6 and sequencing the products. The frequencies of genotypes: G/G, G/A and A/A were 91.7% (242/264), 5.7% (15/264) and 2.6%, respectively, in gastric cancer cases and 91.9%, 7.0% and 1.1%, respectively, in healthy controls. Genotype frequencies in Korean population were very similar to those of Caucasian population. Interestingly, the male gastric cancer patients showed a significantly higher proportion of the G allele (Chi-Square test, P=0.005) compared to female gastric cancer patients. However, the polymorphism was statistically not associated with increased risk of gastric cancer in Korea. When stratified by histological subtype of gastric cancer, the risk was also not statistically significant. Thus, our results suggested that the IVS1 -27G/A polymorphism of KLF6 is not associated with an increased risk for gastric cancer in Korean population.

Cutaneous metastasis resembling acute dermatitis in patient with advanced gastric cancer

The most common metastatic sites from gastric cancer are the liver, intra-abdominal lymph nodes, ovary and peritoneal cavity. Cutaneous metastasis of gastric cancer is rare, and most cutaneous metastases are typically solitary, nodular, have a firm consistency, and are red or hyperpigmented. Thus, cutaneous metastasis is easily distinguished from other skin disease. We report a case of a 60-year-old woman with cutaneous metastasis of gastric cancer, whose facial skin showed painless pruritic eczema, resembling acute dermatitis. She had earlier undergone a total gastrectomy for advanced gastric cancer in our hospital. After 14 months, she developed eczematous facial lesions; the presumptive diagnosis was acute dermatitis. However, skin biopsy unexpectedly revealed cutaneous metastasis of gastric cancer. After 6 months of systemic chemotherapy with capecitabine and cisplatin, the cutaneous metastasis was markedly improved and a clinically complete remission was accomplished.

Association of cyclin D1 G870A polymorphism with susceptibility to gastric cancers in Korean male patients

Cyclin D1 is a key cell cycle regulator that is upregulated in gastric cancer. The common G870A polymorphism of cyclin D1 which can influence cancer susceptibility and disease outcome has been the most frequently investigated. The specific aim of this study is to investigate whether the G870A polymorphism of cyclin D1 was associated with individual susceptibility to gastric cancer in Korea. The frequency of the polymorphism was examined in 253 gastric cancer patients and 442 healthy controls. Polymorphism analysis was performed by amplifying exon 4 of cyclin D1 and sequencing the products. The frequencies of genotypes: G/G, G/A and A/A were 28.1% (71/253), 49.4% (125/253) and 22.5% (57/253), respectively, in gastric cancer cases, and 23.1%, 51.1% and 25.8%, respectively, in healthy controls. Statistically, the polymorphism was not associated with increased risk of gastric cancer. When stratified by histological subtype of gastric cancer, the risk was also not statistically significant. However, the male gastric cancer patients showed a significantly higher proportion of the homozygous G/G genotype and the G allele (Chi-Square test, P = 0.0242 & P = 0.0307) compared to males in the control group. Thus, our findings suggested that the G870A polymorphism of cyclin D1 was not associated with an increased risk for gastric cancer in this population, however, it may contribute to susceptibility to gastric cancer in men.

Effects of chronic angiotensin II receptor antagonist and angiotensin-converting enzyme inhibitor treatments on neurohormonal levels and haemodynamics during cardiopulmonary bypass

BACKGROUND

Chronic treatment with renin-angiotensin system (RAS) antagonists frequently causes deleterious hypotension during anaesthesia. We compared the effects of angiotensin II receptor antagonists (ARA) and angiotensin-converting enzyme inhibitors (ACEI) on neurohormonal levels and haemodynamics during cardiopulmonary bypass (CPB).

METHODS

Forty-four patients undergoing mitral valvular surgery who were treated with either ARA (ARA group, n=14) or ACEI (ACEI group, n=15) over 12 weeks or who were not treated with any RAS antagonist (control group, n=15) were enrolled. The plasma levels of epinephrine, norepinephrine, arginine vasopressin (AVP) and angiotensin II, and haemodynamic variables were measured before (T1) and 15 min after (T2) the start of CPB, before aortic unclamping (T3) and at skin closure (T4). Mean arterial pressure (MAP) was maintained above 60 mm Hg with phenylephrine administration during CPB.

RESULTS

The plasma epinephrine, norepinephrine, AVP and angiotensin II levels increased during CPB in all groups. Compared with the control group, the AVP level was lower at T1 in the ARA group and at T2 in the ARA and ACEI groups. The angiotensin II level was higher at T1, T2 and T3 in ARA group compared with ACEI and control groups. There were no significant differences in the epinephrine and norepinephrine levels among the three groups. The amount of administered phenylephrine during CPB was greater and MAP was lower in the ARA group compared with the ACEI and control groups.

CONCLUSIONS

Chronic ARA treatment resulted in more profound hypotension than ACEI treatment during CPB, and this may be associated with the blockade of angiotensin II receptors by ARA.

Mitochondrial dysfunction induces aberrant insulin signalling and glucose utilisation in murine C2C12 myotube cells

AIMS/HYPOTHESIS

Mitochondrial dysfunction is considered a critical component in the development of diabetes. The aim of this study was to elucidate the molecular mechanisms involved in the development of insulin resistance and diabetes through investigation of mitochondrial retrograde signalling.

MATERIALS AND METHODS

Mitochondrial function of C2C12 myotube cells was impaired by genetic (ethidium bromide) and metabolic (oligomycin) stress, and changes in target molecules related to insulin signalling were analysed.

RESULTS

Concomitant with reductions in mitochondrial membrane potential (DeltaPsim) and ATP synthesis, production of IRS1 and solute carrier family 2 (facilitated glucose transporter), member 4 (SLC2A4, formerly known as GLUT4) were reduced. Moreover, serine phosphorylation of IRS1 increased, resulting in decreased tyrosine phosphorylation. This indicates that mitochondrial dysfunction decreases insulin-stimulated SLC2A4 translocation and glucose uptake. Mitochondrial stress activated c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) signalling in a Ca(2+)-dependent manner, and removal of free Ca(2+) by BAPTA-AM, as well as inhibition of JNK and p38 MAPK, abrogated mitochondrial stress-induced reductions in IRS1 and SLC2A4 production. Mitochondrial dysfunction after oligomycin treatment significantly increased levels of activating transcription factor 3 (ATF3), which represses Irs1 promoter activity. Removal of the 5' flanking region of Irs1 demonstrated that the promoter region within 191 bases from the transcription site may be involved in the transcriptional repression of Irs1 by mitochondrial stress.

CONCLUSIONS/INTERPRETATION

We show distinct mitochondrial retrograde signalling, where Irs1 is downregulated through ATF3 in a Ca(2+)-, JNK- and p38 MAPK-dependent manner, and IRS1 is inactivated. Therefore, mitochondrial dysfunction causes aberrant insulin signalling and abnormal utilisation of glucose, as observed in many insulin resistance states.

Cholecysto-urachal fistula

The urachus is an embryonic remnant that connects the primitive bladder to the allantois. Multiple urachal anomalies have been described, including the urachal sinus, urachal cyst, patent urachus, and urachal diverticulum. We describe an unusual case in which a patient with urinary tract infection and dysuria was ultimately found to have urinary gallstones from a urachal connection with the gallbladder.

On the relationship between speech- and nonspeech-evoked auditory brainstem responses

Auditory brainstem response (ABR) reflects activation of the neural generators along the ascending auditory pathway when a sound is heard. In this study, we explored the relationship between brainstem encoding of click and speech signals in normal-learning children and in those with language-based learning problems. To that end, ABR was recorded from both types of stimuli. We found that the normal pattern of correlation between click- and speech-evoked ABRs was disrupted when speech-evoked ABRs were delayed. Thus, delayed responses to speech were not indicative of clinically abnormal responses to clicks. We conclude that these two responses reflect largely separate neural processes and that only processes involved in encoding complex signals such as speech are impaired in children with learning problems.

The inhibitory effects of roflumilast on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells are mediated by heme oxygenase-1 and its product carbon monoxide

OBJECTIVES

Heme oxygenase-1 (HO-1) is an enzyme that degrades heme into biliverdin, free iron, and carbon monoxide (CO). This enzyme is known to have cytoprotective and anti-inflammatory effects. In this study, we investigated whether roflumilast, a newly developed specific phosphodiesterase 4 (PDE4) inhibitor, mediates some of its anti-inflammatory effects by blocking nitric oxide (NO) and tumor necrosis factor alpha (TNF-alpha) via the induction of HO-1 expression in macrophages.

METHODS

The expression of iNOS and HO-1 was analyzed by western blot analysis. The production of NO and TNF-alpha was assayed by Greiss and ELISA, respectively.

RESULTS

Roflumilast markedly suppressed LPS-induced NO and TNF-alpha production and these phenomena were correlated with the induction of HO-1 protein levels. Moreover, the inhibitory effects of roflumilast on NO production were abrogated by a HO-1 inhibitor and a CO scavenger. Tricarbonyldichlrororuthenium(II) dimer, a CO releasing molecule significantly suppressed NO production.

CONCLUSIONS

These results suggested that roflumilast exerts its anti-inflammatory effects in macrophages through a novel mechanism that involves the action of HO-1 and its product, CO.

Cyclin-dependent kinase-5 prevents neuronal apoptosis through ERK-mediated upregulation of Bcl-2

Cyclin-dependent kinase-5 (Cdk5) is required for neuronal survival, but its targets in the apoptotic pathways remain unknown. Here, we show that Cdk5 kinase activity prevents neuronal apoptosis through the upregulation of Bcl-2. Treatment of SH-SY5Y cells with retinoid acid (RA) and brain-derived neurotrophic factor (BDNF) generates differentiated neuron-like cells. DNA damage triggers apoptosis in the undifferentiated cells through mitochondrial pathway; however, RA/BDNF treatment results in Bcl-2 upregulation and inhibition of the mitochondrial pathway in the differentiated cells. RA/BDNF treatment activates Cdk5-mediated PI3K/Akt and ERK pathways. Inhibition of Cdk5 inhibits PI3K/Akt and ERK phosphorylation and Bcl-2 expression, and thus sensitizes the differentiated cells to DNA-damage. Inhibition of ERK, but not PI3K/Akt, abrogates Cdk5-medidated Bcl-2 upregulation and the protection of the differentiated cells. This study suggests that ERK-mediated Bcl-2 upregulation contributes to BDNF-induced Cdk5-mediated neuronal survival.