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Second Peak (second + peak)
Selected AbstractsVisual event-related potentials in children with phenylketonuriaACTA PAEDIATRICA, Issue 1 2000RM Henderson Visual event-related potentials (ERPs) were examined in 16 children (aged 5,14 y) with phenylketonuria (PKU) and 16 age- and sex-matched controls. Lifetime median measures of phenylalanine (Phe) were 230-460 ,mol/l. The most recent Phe levels were 56,624 ,mol/l. ERPs were recorded whilst the children performed a discrimination task. All stimuli were square wave gratings degree, which appeared for 33 ms. A response to an infrequent grating that differed in orientation or spatial frequency was required. The older children with PKU had a delay in the first peak (P1) of the ERP, and age-related changes in the amplitude of P1. There was attenuation of the second peak across age groups in PKU. There was no evidence of reduced response accuracy or longer reaction times in children with PKU. Latencies of the cognitive P3 were not delayed in PKU. The delayed early peaks are consistent with previous studies that have shown delayed visual evoked potentials in PKU. The lack of differences in reaction time and P3 may be due to relatively good Phe control in children with PKU, or to the simplicity of the task. Suggestions are made for future ERP studies of PKU. [source] Differentiation in life cycle of sympatric populations of two forms of Hyphantria moth in central MissouriENTOMOLOGICAL SCIENCE, Issue 2 2005Makio TAKEDA Abstract Wing patterns of Hyphantria adult male moths collected in central Missouri were examined throughout the breeding season. Three major peaks of adult flight were observed: the first peak consisted mainly of adults with spotted wings, while the second and third peaks consisted of immaculate adults. Black-headed larvae appeared in the field following the first major peak of moth flight, and red-headed larvae appeared in the field following the second peak. Sympatric red-headed and black-headed forms were collected in the field and subsequently reared on an artificial diet under conditions of 16 h light : 8 h dark (LD 16:8) at 25°C. The larval period of the black-headed form was shorter than the red-headed, whereas the pupal period of the black-headed form was longer than the red-headed. Pupal development is retarded in some individuals at high temperatures in the black-headed form. Photoperiodic response curves for pupal diapause were different between the two forms. The critical photoperiod for pupal diapause was 15 h 10 min in the red-headed form, which was longer than that for the black-headed form (14 h 40 min). The two forms responded to shifts in photoperiod differently. These developmental responses temporally separate the two forms in the field; the red-headed and black-headed forms represent a set of adaptations favoring univoltinism and bivoltinism, respectively. Red-headed larvae fed mainly at night, while the black-headed larvae fed without a clear day,night rhythm. Nocturnal feeding in the red-headed form is adaptive to protection against predation, but fails to fully utilize heat units and thus to produce a second generation. [source] Differential expression of antenna and core genes in Prochlorococcus PCC 9511 (Oxyphotobacteria) grown under a modulated light,dark cycleENVIRONMENTAL MICROBIOLOGY, Issue 3 2001Laurence Garczarek The continuous changes in incident solar light occurring during the day oblige oxyphototrophs, such as the marine prokaryote Prochlorococcus, to modulate the synthesis and degradation rates of their photosynthetic components finely. How this natural phenomenon influences the diel expression of photosynthetic genes has never been studied in this ecologically important oxyphotobacterium. Here, the high light-adapted strain Prochlorococcus sp. PCC 9511 was grown in large-volume continuous culture under a modulated 12 h,12 h light,dark cycle mimicking the conditions found in the upper layer of equatorial oceans. The pcbA gene encoding the major light-harvesting complex showed strong diel variations in transcript levels with two maxima, one before the onset of illumination and the other near the end of the photoperiod. In contrast, the mRNA level of psbA (encoding the reaction centre II subunit D1), the monocistronic transcript of psbD (encoding D2) and the dicistronic transcript of psbDC were all tightly correlated with light irradiance, with a minimum at night and a maximum at noon. The occurrence of a second peak during the dark period for the monocistronic transcript of psbC (encoding one of the PS II core Chl a antenna proteins) suggested the involvement of post-transcriptional regulation. Differential expression of the external antenna and core genes may constitute a mechanism of regulation of the antenna size to cope with the excess photon fluxes that Prochlorococcus cells experience in the upper layer of oceans around midday. The 5, ends of all transcripts were mapped, and a conserved motif, 5,-TTGATGA-3,, was identified within the putative psbA and pcbA promoters. [source] Spatiotemporal mapping of sex differences during attentional processingHUMAN BRAIN MAPPING, Issue 9 2009Andres H. Neuhaus Abstract Functional neuroimaging studies have increasingly aimed at approximating neural substrates of human cognitive sex differences elicited by visuospatial challenge. It has been suggested that females and males use different behaviorally relevant neurocognitive strategies. In females, greater right prefrontal cortex activation has been found in several studies. The spatiotemporal dynamics of neural events associated with these sex differences is still unclear. We studied 22 female and 22 male participants matched for age, education, and nicotine with 29-channel-electroencephalogram recorded under a visual selective attention paradigm, the Attention Network Test. Visual event-related potentials (ERP) were topographically analyzed and neuroelectric sources were estimated. In absence of behavioral differences, ERP analysis revealed a novel frontal-occipital second peak of visual N100 that was significantly increased in females relative to males. Further, in females exclusively, a corresponding central ERP component at around 220 ms was found; here, a strong correlation between stimulus salience and sex difference of the central ERP component amplitude was observed. Subsequent source analysis revealed increased cortical current densities in right rostral prefrontal (BA 10) and occipital cortex (BA 19) in female subjects. This is the first study to report on a tripartite association between sex differences in ERPs, visual stimulus salience, and right prefrontal cortex activation during attentional processing. Hum Brain Mapp 2009. © 2009 Wiley-Liss, Inc. [source] HtrA2 is up-regulated in the rat testis after experimental cryptorchidismINTERNATIONAL JOURNAL OF UROLOGY, Issue 2 2006TETSUO HAYASHI Aim:, The aim of the present study was to elucidate the role of high temperature requirement A2 (HtrA2) in germ cell loss in the heat-stressed testis. Methods:, We examined the expression of HtrA2, caspase-9 activity and proteolytic activity of HtrA2 in the rat testis, and their in vivo responses to experimental cryptorchid treatment. Results:, Northern analysis revealed the expression of HtrA2 mRNA peaked at days 1 and 7 after cryptorchid treatment. While expression of HtrA2 mRNA was seen in the spermatogonium, spermatocytes and some spermatids in normal adult rat testis, experimental cryptorchidism treatment resulted in a marked increase in its signal intensity in spermatocytes and some spermatids, and the layers of spermatogonium and early primary spermatocytes became negative at days 1 and 7 after the treatment. However, the spermatogonium, Sertoli cells and interstitial cells appeared to have strong intensities at days 14, 28 and 56 after the treatment. Western analysis revealed the expression of HtrA2 protein peaked at day 2 coinciding with the increase of positive spermatogonium, the appearance of protein-positive interstitial cells, and day 28 coinciding with the reappearance of protein-positive interstitial cells. Caspase-9 activity peaked at day 2 and HtrA2 proteolytic activity peaked at day 28. Consequently, the first peak of HtrA2 mRNA expression was followed by the peak of caspase-9 activity and the second peak was followed by the peak of proteolytic activity; however, the second peak of mRNA expression had considerable chronological difference from that of the protein. Conclusion:, These findings suggest the probabilities that the heat stress results in germ cell death by a caspase-independent manner with the elevation of HtrA2 proteolytic activity, as well as a caspase-dependent manner with the elevation of caspase-9 activity. [source] Os incae: variation in frequency in major human population groupsJOURNAL OF ANATOMY, Issue 2 2001TSUNEHIKO HANIHARA The variation in frequency of the Inca bone was examined in major human populations around the world. The New World populations have generally high frequencies of the Inca bone, whereas lower frequencies occur in northeast Asians and Australians. Tibetan/Nepalese and Assam/Sikkim populations in northeast India have more Inca bones than do neighbouring populations. Among modern populations originally derived from eastern Asian population stock, the frequencies are highest in some of the marginal isolated groups. In Central and West Asia as well as in Europe, frequency of the Inca bone is relatively low. The incidence of the complete Inca bone is, moreover, very low in the western hemisphere of the Old World except for Subsaharan Africa. Subsaharan Africans show as a whole a second peak in the occurrence of the Inca bone. Geographical and ethnographical patterns of the frequency variation of the Inca bone found in this study indicate that the possible genetic background for the occurrence of this bone cannot be completely excluded. Relatively high frequencies of the Inca bone in Subsaharan Africans indicate that this trait is not a uniquely eastern Asian regional character. [source] Estimating food consumption of marine predators: Antarctic fur seals and macaroni penguinsJOURNAL OF APPLIED ECOLOGY, Issue 1 2002I.L. Boyd Summary 1Estimating food consumption is central to defining the ecological role of marine predators. This study developed an algorithm for synthesizing information about physiology, metabolism, growth, diet, life history and the activity budgets of marine predators to estimate population energy requirements and food consumption. 2Two species of marine predators (Antarctic fur seal Arctocephalus gazella and macaroni penguin Eudyptes chrsolophus) that feed on krill in the Southern Ocean were used as examples to test the algorithm. A sensitivity analysis showed that estimates of prey consumed were most sensitive to uncertainty in some demographic variables, particularly the annual survival rate and total offspring production. Uncertainty in the measurement of metabolic rate led to a positive bias in the mean amount of food consumed. Uncertainty in most other variables had little influence on the estimated food consumed. 3Assuming a diet mainly of krill Euphausia superba, annual food consumption by Antarctic fur seals and macaroni penguins at the island of South Georgia was 3·84 [coefficient of variation (CV) = 0·11] and 8·08 (CV = 0·23) million tonnes, respectively. This was equivalent to a total annual carbon consumption of 0·35 (CV = 0·11) and 0·72 (CV = 0·23) G tonnes year,1. Carbon expired as CO2 was 0·26 (CV = 0·06) and 0·65 (CV = 0·19) G tonnes year,1 for fur seals and macaroni penguins, respectively. The per capita food consumption varied depending upon sex and age but, overall, this was 1·7 (CV = 0·22) tonnes year,1 for Antarctic fur seals and 0·45 (CV = 0·22) tonnes year,1 for macaroni penguins. 4The algorithm showed that the seasonal demand for food peaked in both species in the second half of the breeding season and, for macaroni penguins, there was a second peak immediately after moult. Minimum food demand occurred in both species during the first half of the breeding season. 5As both Antarctic fur seals and macaroni penguins compete for krill with a commercial fishery, these results provide an insight into the seasons and stages of the life cycle in which competition is likely to be greatest. [source] Prevalence and genotype distribution of cervical human papillomavirus infection in MacaoJOURNAL OF MEDICAL VIROLOGY, Issue 10 2010Yuk-Ching Yip Abstract Population-specific epidemiological data on human papillomavirus (HPV) infection are essential for formulating strategies to prevent cervical cancer. The age-specific prevalence of HPV infection was determined among 1,600 women enrolled for cervical screening in Macao. A U-shaped age-specific prevalence curve with a first peak (prevalence rate, 10%) at 20,25 years and a second peak (13%) at 51,55 years was observed. Co-infections with multiple types were detected in 32.5% of HPV-positive subjects and without significant variation among different age groups (P,=,0.318). The majority (84.6%) of the positive samples harbored high- or probable high-risk HPV types, and these types also exhibited a similar U-shaped age-specific prevalence curve. In contrast, low and unknown-risk HPV types remained at a low prevalence (1.5,2.5%) throughout the age groups between 20 and 50 years, and with a small peak (4.5%) at 51,55 years. HPV 52 was the most common type found in 26.8% of positive samples, followed by HPV 16 (15.5%), HPV 68 (11.4%), HPV 18 and HPV 58 (8.9% each), HPV 54 (8.1%), HPV 53 (7.3%), HPV 39 (6.5%), HPV 33 and HPV 66 (5.7% each). In conclusion, because of the early peak of infection, vaccination and educational campaigns in Macao should start early and target at teenagers. The presence of a second peak containing mainly high-risk HPV types in older women indicates the need to evaluate the cover of the cervical screening programme for older women. Further study to determine the contribution of HPV 52 in high-grade cervical neoplasia and invasive cancers in Macao is warranted. J. Med. Virol. 82:1724,1729, 2010. © 2010 Wiley-Liss, Inc. [source] Activity-dependent somatostatin gene expression is regulated by cAMP-dependent protein kinase and Ca2+ -calmodulin kinase pathwaysJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2010Isabel Sánchez-Muñoz Abstract Ca2+ influx through L-type voltage-gated Ca2+ channels (L-VSCC) is required for K+ -induced somatostatin (SS) mRNA. Increase in intracellular Ca2+ concentration leads to the activation of cyclic AMP-responsive element binding protein (CREB), a key regulator of SS gene transcription. Several different protein kinases possess the capability of driving CREB upon membrane depolarization. We investigated which of the signalling pathways involved in CREB activation mediates SS gene induction in response to membrane depolarization in cerebrocortical cells exposed to 56 mM K+. Activity dependent phosphorylation of CREB in Ser133 was immunodetected. Activation of CREB was biphasic showing two peaks at 5 and 60 min. The selective inhibitors of extracellular signal related protein kinase/mitogen-activated protein kinase (ERK/MAPK) PD098059, cyclic-AMPdependent protein kinase (cAMP/PKA) H89 and RpcAMPS, and Ca2+/calmodulin-dependent protein kinases (CaMKs) pathways KN62 and KN93 were used to determine the signalling pathways involved in CREB activation. Here we show that the early activation of CREB was dependent on cAMP/PKA along with CaMKs pathways whereas the ERK/MAPK and CaMKs were implicated in the second peak. We observed that H89, RpcAMPS, KN62 and KN93 blocked K+ -induced SS mRNA whereas PD098059 did not. These findings indicate that K+ -induced SSmRNA is mediated by the activation of cAMP/PKA and CaMKs pathways, thus suggesting that the early activation of CREB is involved in the induction of SS by neuronal activity. We also demonstrated, using transient transfections of cerebrocortical cells, that K+ induces the transcriptional regulation of the SS gene through the cAMP-responsive element (CRE) sequence located in the SS promoter. © 2009 Wiley-Liss, Inc. [source] Prediction of the possibility of the second peak of drug plasma concentration time curve after iv bolus administration from the standpoint of the traditional multi-compartmental linear pharmacokineticsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2008Leonid M. Berezhkovskiy Abstract It is shown that the existence of the second peak on the drug plasma concentration time curve Cp(t) after iv bolus dosing can be explained by considering the traditional multi-compartmental linear pharmacokinetics. It was found that a direct solution of the general three-compartment model yields the second peak of Cp(t) for the certain values of the rate constants, and Cp(t) includes the term with oscillating preexponent, that is, K,sin(,t,+,,),exp(,,t), in this case. The considered model describes the drug entero-hepatic recirculation in the species which do not have gall bladder (rats). The model fit of the experimental data from rat pharmacokinetic studies where the second peak of Cp(t) was observed, yields the rate of bile production that is consistent with the physiological value (,0.7 mL/h). © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:2385,2393, 2008 [source] Synthesis and characterization of new alternating, amphiphilic, comblike copolymers of poly(ethylene oxide) macromonomer and N -phenylmaleimideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2005Luminita Cianga Abstract A surface-active p -vinyl benzyloxy-,-hydroxy-poly(ethylene oxide) macromonomer containing 22 pendant structural units of ethylene oxide (St,PEO22) was synthesized with an initiation method. Because of its solubility in a large variety of solvents, the free-radical copolymerization with electron-acceptor N -phenylmaleimide (NPMI) was performed at 60 °C in benzene and tetrahydrofuran (THF) as isotropic media and in a water,THF mixture or water as a heterogeneous medium. Oil-soluble 2,2,-azobisisobutyronitrile and water-soluble 4,4,-azobis(4-cyanovaleric acid) were used as the initiators at fixed concentrations. Two different St,PEO22/NPMI comonomer ratios (1/1 and 3/7) at a fixed total comonomer concentration in the polymerization system were used. The structures, compositions, and microstructure peculiarities of the obtained alternating, amphiphilic, comblike copolymers were determined by NMR analysis. For the copolymers synthesized in hydrophilic media, differential scanning calorimetry showed, near the endothermic peak attributed to the melting of the poly(ethylene oxide) side chains, the presence of a second peak due to the partially ordered phase that could exist between the crystalline state and the isotropic melt. Also, the thermal stability of the obtained copolymers was studied with thermogravimetric analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 479,492, 2005 [source] Michaelis-Menten Elimination Kinetics of Acetaldehyde During Ethanol OxidationALCOHOLISM, Issue 2002Tatsuya Fujimiya Background Acetaldehyde (AcH) is a toxic metabolite of ethanol (EtOH). The pharmacokinetics of blood AcH during EtOH oxidation was studied with or without the administration of aldehyde dehydrogenase 2 inhibitor (cyanamide) in rabbits. Methods An bolus of EtOH saline solution (0.25, 0.5, 1.0, 1.5, and 2.0 g/kg) was injected intravenously. Cyanamide was administered intraperitoneally (25 mg/kg body weight) to the cyanamide-treated group. Blood EtOH and AcH concentrations were measured by using head-space gas chromatography. Results In the control group, the first peak of the blood AcH appeared immediately and the second elevation appeared 1 to 4 hr after administration at a high EtOH dose. The blood AcH levels other than the second elevation part were significantly correlated to the blood EtOH levels. In the cyanamide-treated group, a peak and a plateau formed at the time corresponding to the second peak in the control group. The peak and plateau concentration of AcH increased markedly. We attempted simultaneous curve fitting, using the five blood EtOH and AcH concentration-time curves, to determine the pharmacokinetic model. Consequently, the AcH elimination was best described by a Michaelis-Menten kinetic model in both groups. Conclusions The blood AcH profile was suggested to consist of the first and second components that are related to the blood EtOH concentration itself and the metabolic formation of AcH, respectively. With higher EtOH doses or aldehyde dehydrogenase 2 inhibition, the second component becomes prominent as a result of the capacity-limited property of the metabolism of AcH, which is described by Michaelis-Menten elimination kinetics. [source] Characterization of ginger proteases and their potential as a rennin replacementJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2009Hou-Pin Su Abstract BACKGROUND: Ginger rhizome (Zingiber officinale Roscoe) contains ginger proteases and has proteolytic activity. Ginger proteases have been used for tenderizing meat but rarely for milk clotting. The purpose of this study was to purify ginger proteases and to research their biochemical characteristics. RESULTS: The milk clotting activity (MCA) and proteolytic activity (PA) of the proteases was stable after storage at 4 °C for 24 h. The MCA and PA of fresh ginger juice with 0.2% L -ascorbic acid remained stable for 6 days at 4 °C. When under storage at ,80 °C for 2 months, the MCA and PA of the fresh ginger juice and acetone precipitate were still high. Two peaks with protease activity were purified from a DEAE FF ion-exchange column; the specific activity (units mg,1 protein) of the MCA (MCSA) and PA (PSA) for the first peak was significantly higher than the second peak (P < 0.05). The protease activity of the ginger proteases was significantly inhibited by E-64, leupeptin, and iodoacetic acid. Zymography results showed that two protease fractions purified from ginger juice with 62 and 82 kDa had a higher PA against ,- and ,-casein than against ,-casein. CONCLUSION: The ascorbic acid addition significantly stabilized the MCA and PA of ginger proteases. The protease inhibition test suggested that ginger proteases belonged to the cysteine type. The biochemical characteristics of ginger protease described in this paper can provide useful information for making new milk curd products. Copyright © 2009 Society of Chemical Industry [source] Effect of nitrogen fertilisation on below-ground carbon allocation in lettuceJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2002Y Kuzyakov Abstract The aims of this study were to investigate the effect of nitrogen (N) fertilisation on the below-ground carbon (C) translocation by lettuce and the CO2 efflux from its rhizosphere. Two N fertilisation levels (80 and 160,kg N,ha,1) and two growth stages (43 and 60 days) were tested. 14C pulse labelling of shoots followed by 14C monitoring in the soil, roots, microbial biomass and CO2 efflux from the soil was used to distinguish between root-derived and soil organic matter-derived,C. The 14C allocation in the below-ground plant parts was 1.5,4.6 times lower than in the leaves. The total quantity of C translocated into the soil was much lower than in the case of cereals and grasses, amounting to 120 and 160,kg C,ha,1 for low and high N respectively. N fertilisation diminished the proportion of assimilated C translocated below ground. About 5,8% of the assimilated C was respired into the rhizosphere. Root-derived CO2 (the sum of root respiration and rhizomicrobial respiration) represented about 15,60% of the total CO2 efflux from the planted soil. Two peaks were measured in the 14CO2 efflux: the first peak (4,5,h after labelling) was attributed to root respiration, whilst the second peak (12,h after labelling) was attributed to microbial respiration of exudates. Twelve days after labelling, 0.15,0.25% of the assimilated C was found in the microbial biomass. The higher microbial activity in the lettuce rhizosphere doubled the soil organic matter decomposition rate compared with unplanted soil. © 2002 Society of Chemical Industry [source] Comparison of the spectral emission of lux recombinant and bioluminescent marine bacteria,LUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 3 2003Gérald Thouand Abstract The purpose of the present paper was to study the influence of bacteria harbouring the luciferase-encoding Vibrio harveyi luxAB genes upon the spectral emission during growth in batch-culture conditions. In vivo bioluminescence spectra were compared from several bioluminescent strains, either naturally luminescent (Vibrio fischeri and Vibrio harveyi) or in recombinant strains (two Gram-negative Escherichia coli::luxAB strains and a Gram-positive Bacillus subtilis::luxAB strain). Spectral emission was recorded from 400,nm to 750,nm using a highly sensitive spectrometer initially devoted to Raman scattering. Two peaks were clearly identified, one at 491,500,nm (± 5,nm) and a second peak at 585,595 (± 5,nm) with the Raman CCD. The former peak was the only one detected with traditional spectrometers with a photomultiplier detector commonly used for spectral emission measurement, due to their lack of sensitivity and low resolution in the 550,650,nm window. When spectra were compared between all the studied bacteria, no difference was observed between natural or recombinant cells, between Gram-positive and Gram-negative strains, and growth conditions and growth medium were not found to modify the spectrum of light emission. Copyright © 2003 John Wiley & Sons, Ltd. [source] Viruses and atypical bacteria associated with asthma exacerbations in hospitalized children,PEDIATRIC PULMONOLOGY, Issue 6 2010Alberto F. Maffey MD Abstract Objectives and Working Hypothesis To evaluate the prevalence of respiratory viruses Mycoplasma pneumoniae and Chlamydophila pneumoniae and gain insight into their seasonal circulation pattern in children with acute asthma exacerbations in a temperate southern hemisphere region. Study Design Patients hospitalized between 3 months and 16 years of age were included in a 1-year prospective, observational, cross-sectional study. Respiratory secretions were collected and the presence of different viruses and atypical bacteria analyzed by immunofluorescence and polymerase chain reaction. Results Two hundred nine patients (118 females) aged (mean,±,SD) 4.4,±,4 years were included. A potential causative agent was detected in 78% of the patients. The most frequently detected viruses were respiratory syncytial virus (HRSV) (n,=,85; 40%) and rhinovirus (HRV) (n,=,52; 24.5%); M. pneumoniae and C. pneumoniae were detected in 4.5% and 2% of the cases, respectively. Patients with HRSV (vs. HRV) were hospitalized for a longer time (6.7 vs. 5.2 days, P,=,0.012), required more days of oxygen supply (5.1 vs. 3.4, P,=,0.005), had a longer duration of the exacerbation before hospitalization (3.6 vs. 1.9 days, P,=,0.001) and were younger (3.7 vs. 5.1 years, P,=,0.012). Three peaks of admissions were observed. A first peak (early autumn) caused by HRV, a second peak (winter) caused mainly by HRSV and a third one (spring), caused by HRSV, an increase in HMPV together with a second outbreak of HRV. Conclusions Children with an acute asthma exacerbation presented a high prevalence of respiratory viruses. Most hospitalizations corresponded to seasonal increases in prevalence of HRV and HRSV. Pediatr Pulmonol. 2010; 45:619,625. © 2010 Wiley-Liss, Inc. [source] Viscoelastic properties of polyacrylonitrile terpolymers during thermo-oxidative stabilization (cyclization)POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2008K. I. Suresh Abstract A study on the thermo-oxidative stabilization (cyclization) of polyacrylonitrile (PAN) terpolymers using dynamic mechanical thermal analysis (DMTA) is reported in this article. When the changes in viscoelastic properties were monitored in a rectangular tension mode, besides the tan , peak characteristic of the glass transition observed below 200°C, the copolymer and the terpolymer displayed a second peak above 200°C due to the cyclization leading to the formation of ladder structures. The initiation temperature of the cyclization process as well as the peak temperature is found to depend on the acid value and the composition of the precursor polymer. The results presented show that monitoring the changes in viscoelastic properties during cyclization provides insight into the material properties as a result of the chemical changes that are taking place. These observations were confirmed by structural characterization using IR spectroscopy, and the observed chemical changes agree with the literature studies, as due to the thermal cyclization process. Copyright © 2008 John Wiley & Sons, Ltd. [source] Role of TNF, in Early Chemokine Production and Leukocyte Infiltration into Heart AllograftsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2010D. Ishii The acute phase cytokines IL-1,, IL-6 and TNF, are produced early during inflammatory processes, including ischemia-reperfusion. The appearance and role of these cytokines in the early inflammation following reperfusion of grafts remain poorly defined. This study investigated the role of TNF, in the induction of early leukocyte infiltration into vascularized heart allografts. TNF, and IL-6 mRNA levels reached an initial peak 3 h posttransplant and a second peak at 9,12 h with equivalent levels in iso- and allografts. A single dose of anti-TNF, mAb given at reperfusion decreased neutrophil and macrophage chemoattractant levels and early neutrophil, macrophage and memory CD8 T-cell infiltration into allografts. Anti-TNF, mAb also extended graft survival from 8.6 ± 0.6 days to 14.1 ± 0.8 days. When assessed on day 7 posttransplant, the number of donor-reactive CD8 T cells producing IFN-, in the spleen was reduced almost 70% in recipients treated with anti-TNF, mAb. Whereas anti-CD154 mAb prolonged survival to day 21, administration of anti-TNF, and anti-CD154 mAb delayed rejection to day 32 and resulted in long-term (>80 days) survival of 40% of the heart allografts. These data implicate TNF, as an important mediator of early inflammatory events in allografts that undermine graft survival. [source] The prevalence and significance of high-risk human papillomavirus DNA test in southern Malaysia and SingaporeAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 3 2009Sun-Kuie TAY Aim of Study: To investigate the prevalence of high-risk human papillomavirus (HPV) and its associated cytological abnormalities among women attending cervical screening clinics in southern Malaysia and Singapore. Method: Laboratory results of Hybrid Capture-II (Digene) HPV DNA and liquid-based cytology tests of consecutive women who had screening performed between January 2004 and December 2006 were studied retrospectively. Results: Of 2364 women studied, the overall prevalence of high-risk HPV DNA detection rate was 25.6%. The prevalence peaked at 49.1% for women between 20 and 24 years old and declined to 23% among women between the age of 30 and 49 years. A small second peak of prevalence rate of 30% was observed among women above the age of 50 years old. 76.1% of the high-risk HPV infection regressed within the study period. An incidence infection rate of 16% was noted among a small group of women who had a second HPV DNA test. A total of 1153 women had both the HPV DNA and the cytology tests. Cytological abnormality (ASCUS or more) was detected in 8.9% in HPV DNA-positive group and in 3.1% in HPV DNA-negative group (P < 0.001). The risk ratio for HSIL was 9.8 for HPV-positive women compared to HPV-negative women. The prevalence of cytological abnormalities increased with increasing age of the women. Conclusion: The epidemiology and clinical impact of high-risk HPV infection for women in Southern Malaysia and Singapore were indistinguishable from experience elsewhere. The apparent moderately high incidence of cervical cancer was explainable by suboptimal screening program. [source] Pharmacokinetics and metabolism of neferine in rats after a single oral administrationBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2007Ying Huang Abstract The present study utilized HPLC and LC-MS approaches to investigate the pharmacokinetics and metabolism of neferine (a bisbenzylisoquinoline alkaloid). The plasma concentration-time curves of neferine (10, 20 and 50 mg/kg, i.g.) showed double absorption peaks with the first peak at 10 min and the second peak at 1 h. The t was 15.6 h, 22.9 h and 35.5 h, for each of these doses, respectively. Neferine distributed rapidly into different organ systems, with the highest concentrations found in the liver, followed by the lung, kidney and heart at doses of 10 or 20 mg/kg. At 50 mg/kg dose, concentrations of the kidney and lung were higher than those of others. Moreover, this compound was mainly metabolized in the liver and converted partially by CYP2D6 to liensinine, isoliensinine, desmethyl-liensinine and desmethyl-isoliensinine. Copyright © 2007 John Wiley & Sons, Ltd. [source] Thymoquinone protects renal tubular cells against tubular injuryCELL BIOCHEMISTRY AND FUNCTION, Issue 3 2008Ahmed Amir Radwan Sayed Abstract In this work the effect of angiotensin II (AT II) on proximal tubular epithelial cells (pTECs) in vitro was studied. AT II was found to activate the nuclear factor ,B (NF- ,B) and its controlled genes, for example, interleukin 6 (IL-6) of pTECs in a time-dependent manner. Two points with maximum NF- ,B activation were found, the first after 12,h and the second after 3.5 days. The first point may be due to activation of NF- ,B in pTECs in response to AT II while the second may be due to activation of the advanced glycation end product (AGE)/receptor of the AGE (RAGE) system. Thymoquinone (TQ) was found to decrease NF- ,B activation in a dose-dependant manner with maximum inhibitory effect at a concentration of 500,nM. Also, pre-incubation of pTECs with TQ leads to disappearance of the second peak of NF- ,B. These data are consistent with results obtained from IL-6 enzyme-linked immunosorbent assay (ELISA) and transient transfection experiments. The results explain the therapeutic value of TQ which can be used to delay end stage renal diseases in diabetics. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||