The possible roles of hyperpolarization-activated cyclic nucleotide channels in regulating pacemaker activity in colonic interstitial cells of Cajal

BACKGROUND: Hyperpolarization-activated cyclic nucleotide (HCN) channels are pacemaker channels that regulate heart rate and neuronal rhythm in spontaneously active cardiac and neuronal cells. Interstitial cells of Cajal (ICCs) are also spontaneously active pacemaker cells in the gastrointestinal tract. Here, we investigated the existence of HCN channel and its role on pacemaker activity in colonic ICCs. METHODS: We performed whole-cell patch clamp, RT-PCR, and Ca(2+)-imaging in cultured ICCs from mouse mid colon. RESULTS: SQ-22536 and dideoxyadenosine (adenylate cyclase inhibitors) decreased the frequency of pacemaker potentials, whereas both rolipram (cAMP-specific phosphodiesterase inhibitor) and cell-permeable 8-bromo-cAMP increased the frequency of pacemaker potentials. CsCl, ZD7288, zatebradine, clonidine (HCN channel blockers), and genistein (a tyrosine kinase inhibitor) suppressed the pacemaker activity. RT-PCR revealed expression of HCN1 and HCN3 channels in c-kit and Ano1 positive colonic ICCs. In recordings of spontaneous intracellular Ca(2+) [Ca(2+)](i) oscillations, rolipram and 8-bromo-cAMP increased [Ca(2+)](i) oscillations, whereas SQ-22536, CsCl, ZD7288, and genistein decreased [Ca(2+)](i) oscillations. CONCLUSIONS: HCN channels in colonic ICCs are tonically activated by basal cAMP production and participate in regulation of pacemaking activity

Effects of HA and NA glycosylation pattern changes on the transmission of avian influenza A(H7N9) virus in guinea pigs

AbstractAvian influenza H7N9 virus has posed a concern of potential human-to-human transmission by resulting in seasonal virus-like human infection cases. To address the issue of sustained human infection with the H7N9 virus, here we investigated the effects of hemagglutinin (HA) and neuraminidase (NA) N-linked glycosylation (NLG) patterns on influenza virus transmission in a guinea pig model. Based on the NLG signatures identified in the HA and NA genetic sequences of H7N9 viruses, we generated NLG mutant viruses using either HA or NA gene of a H7N9 virus, A/Anhui/01/2013, by reverse genetics on the 2009 pandemic H1N1 virus backbone. For the H7 HA NLG mutant viruses, NLG pattern changes appeared to reduce viral transmissibility in guinea pigs. Intriguingly, however, the NLG changes in the N9 NA protein, such as a removal from residue 42 or 66 or an addition at residue 266, increased transmissibility of the mutant viruses by more than 33%, 50%, and 16%, respectively, compared with a parental N9 virus. Given the effects of HA-NA NLG changes with regard to viral transmission, we then generated the HA-NA NLG mutant viruses harboring the H7 HA of double NLG addition and the N9 NA of various NLG patterns. As seen in the HA NLG mutants above, the double NLG-added H7 HA decreased viral transmissibility. However, when the NA NLG changes occurred by a removal of residue 66 and an addition at 266 were additionally accompanied, the HA-NA NLG mutant virus recovered the transmissibility of its parental virus. These demonstrate the effects of specific HA-NA NLG changes on the H7N9 virus transmission by highlighting the importance of a HA-NA functional balance

Prevention of hypoglycemia-induced neuronal death by minocycline

Diabetic patients who attempt strict management of blood glucose levels frequently experience hypoglycemia. Severe and prolonged hypoglycemia causes neuronal death and cognitive impairment. There is no effective tool for prevention of these unwanted clinical sequelae. Minocycline, a second-generation tetracycline derivative, has been recognized as an anti-inflammatory and neuroprotective agent in several animal models such as stroke and traumatic brain injury. In the present study, we tested whether minocycline also has protective effects on hypoglycemia-induced neuronal death and cognitive impairment. To test our hypothesis we used an animal model of insulin-induced acute hypoglycemia. Minocycline was injected intraperitoneally at 6 hours after hypoglycemia/glucose reperfusion and injected once per day for the following 1 week. Histological evaluation for neuronal death and microglial activation was performed from 1 day to 1 week after hypoglycemia. Cognitive evaluation was conducted 6 weeks after hypoglycemia. Microglial activation began to be evident in the hippocampal area at 1 day after hypoglycemia and persisted for 1 week. Minocycline injection significantly reduced hypoglycemia-induced microglial activation and myeloperoxidase (MPO) immunoreactivity. Neuronal death was significantly reduced by minocycline treatment when evaluated at 1 week after hypoglycemia. Hypoglycemia-induced cognitive impairment is also significantly prevented by the same minocycline regimen when subjects were evaluated at 6 weeks after hypoglycemia. Therefore, these results suggest that delayed treatment (6 hours post-insult) with minocycline protects against microglial activation, neuronal death and cognitive impairment caused by severe hypoglycemia. The present study suggests that minocycline has therapeutic potential to prevent hypoglycemia-induced brain injury in diabetic patients

Dual Silencing of Hsp27 and c-FLIP Enhances Doxazosin-Induced Apoptosis in PC-3 Prostate Cancer Cells

We evaluated effect of dual gene silencing of Hsp27 and c-FLIP in doxazosin-induced apoptosis of PC-3 cell. After transfection using Hsp27 and c-FLIP siRNA mixture (dual silencing), doxazosin treatment was done at the concentrations of 1, 10, and 25 μM. We checked apoptosis of PC-3 cells with and TUNEL staining. We also checked interaction between Hsp27 and C-FLIP in the process of apoptosis inhibition. Spontaneous apoptotic index was 5% under single gene silencing of Hsp27 and c-FLIP and 7% under dual silencing of Hsp27 and c-FLIP. When doxazosin treatment was added, apoptotic indices increased in a dose-dependent manner (1, 10, and 25 μM): nonsilencing 10, 27, and 52%; Hsp27-silencing: 14, 35, and 68%; c-FLIP silencing: 21, 46, and 78%; dual silencing: 38, 76, and 92%. While c-FLIP gene expression decreased in Hsp27- silenced cells, Hsp27 gene expression showed markedly decreased pattern in the cells of c-FLIP silencing. The knockout of c-FLIP and Hsp27 genes together enhances apoptosis even under 1 μM, rather than low concentration, of doxazosin in PC-3 cells. This finding suggests a new strategy of multiple knockout of antiapoptotic and survival factors in the treatment of late-stage prostate cancer refractory to conventional therapy

Epidemiological characteristics of ovarian cancer in Korea

Objective: This study was conducted to examine recent trends in ovarian cancer incidence and mortality and secular trends in demographic factors in Korea. Methods: With the data from Korea Central Cancer Registry, International Agency for Research on Cancer, Korean Death Registry, and World Health Organization`s Statistical Information System, we calculated age-standardized incidence and mortality rates for ovarian cancer. Also we estimated future incidence of ovarian and cervical cancer using linear regression model. To assess the demographic trend, data from national surveys in Korea or results from published papers were searched. Results: Ovarian cancer incidence rate was similar to that in women worldwide but lower than those in Western countries, and the trend has been increased steadily. Ovarian cancer-related mortality rates have been increasing in Korea, even though those in western and some Asian countries, such as China, have been decreasing. Age-specific incidence rate and mortality rate showed steep increases with advancing age. The incidence rate of ovarian cancer was estimated to surpass that of uterine cervix cancer in 2015. Korea showed rapid changes in nutritional, reproductive, and anthropometric factors. Conclusion: These recent trends in ovarian cancer incidence and mortality may be partly attributed to gradual westernizing of life styles and to changes in socio-demographic behavior factors. In particular, the increasing trend in ovarian cancer mortality in Korea may be attributed to a real rise in mortality as well as, in part, a decline in misclassification bias related to an increase in the proportion of deaths confirmed by physician diagnosis.Kolahdooz F, 2010, AM J CLIN NUTR, V91, P1752, DOI 10.3945/ajcn.2009.28415Kim HG, 2010, ELECTROCHEM SOLID ST, V13, pH42, DOI 10.1149/1.3266905Cho GJ, 2010, EUR J PEDIATR, V169, P89, DOI 10.1007/s00431-009-0993-1Hirabayashi Y, 2009, JPN J CLIN ONCOL, V39, P860, DOI 10.1093/jjco/hyp168Park SK, 2009, J KOREAN MED ASSOC, V52, P937Ushijima K, 2009, J GYNECOL ONCOL, V20, P67, DOI 10.3802/jgo.2009.20.2.67Kim K, 2009, J GYNECOL ONCOL, V20, P72, DOI 10.3802/jgo.2009.20.2.72ALTEKRUSE SF, 2009, SEER CANC STAT REV 1*WHO, 2009, MORT BURD DIS EST WH*MIN HLTH WELF FAM, 2009, ANN REP CANC INC 200*KIHASA, 2009, NAT SURV DAT MARR FEBeral V, 2008, LANCET, V371, P303AHN YO, 2007, J PREV MED PUB HLTH, V40, P265PARK MJ, 2006, KOREAN J PEDIAT, V49, P610Brewster WR, 2005, NAT CLIN PRACT ONCOL, V2, P286, DOI 10.1038/ncponc0198Brinton LA, 2005, FERTIL STERIL, V83, P261, DOI 10.1016/j.fertnstert.2004.09.016Zografos GC, 2004, INT J GYNECOL CANCER, V14, P721JO MW, 2004, J PREV MED PUBLIC HL, V37, P345HWANG N, 2003, HLTH WELL POLICY FOR, V82, P88Moorman PG, 2002, CANCER CAUSE CONTROL, V13, P807PARKIN DM, 2002, IARC SCI PUBLICATION, V155Olaitan A, 2000, BRIT J OBSTET GYNAEC, V107, P1094Risch HA, 1998, J NATL CANCER I, V90, P1774Nugent D, 1998, BRIT J OBSTET GYNAEC, V105, P584KIM NI, 1995, KOREAN J POPUL STUD, V18, P1WHITTEMORE AS, 1992, AM J EPIDEMIOL, V136, P1184PARAZZINI F, 1991, GYNECOL ONCOL, V43, P9*KOR NAT STAT OFF, 1983, KOR STAT INF SYST KOSEGI M, 1966, CANC MORTALITY SELEC*WHO, GLOB 2008*SIZ KOR, COMP EST ACC YEAR*MIN HLTH WELF KOR, KOR NAT HLTH NUTR EX*KOR NAT STAT OFF, PIL RES BIRTH STAT 2*KOR NAT STAT OFF, POP PROJ KOR 2005 20*KOR STAT INF SERV, POP STAT