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Selected AbstractsAsymptotic self-similarity and wavelet estimation for long-range dependent fractional autoregressive integrated moving average time series with stable innovationsJOURNAL OF TIME SERIES ANALYSIS, Issue 2 2005Stilian Stoev Primary 60G18; 60E07; Secondary 62M10; 63G20 Abstract., Methods for parameter estimation in the presence of long-range dependence and heavy tails are scarce. Fractional autoregressive integrated moving average (FARIMA) time series for positive values of the fractional differencing exponent d can be used to model long-range dependence in the case of heavy-tailed distributions. In this paper, we focus on the estimation of the Hurst parameter H = d + 1/, for long-range dependent FARIMA time series with symmetric , -stable (1 < , < 2) innovations. We establish the consistency and the asymptotic normality of two types of wavelet estimators of the parameter H. We do so by exploiting the fact that the integrated series is asymptotically self-similar with parameter H. When the parameter , is known, we also obtain consistent and asymptotically normal estimators for the fractional differencing exponent d = H , 1/,. Our results hold for a larger class of causal linear processes with stable symmetric innovations. As the wavelet-based estimation method used here is semi-parametric, it allows for a more robust treatment of long-range dependent data than parametric methods. [source] Prolonged exposure to inhaled nitric oxide transiently modifies tubular function in healthy piglets and promotes tubular apoptosisACTA PHYSIOLOGICA, Issue 4 2009W. Go, dzik Abstract Aim:, Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator. We hypothesized that those piglets exposed to prolonged iNO react with a modified renal function. Methods:, Randomized, placebo-controlled exposure to 40 p.p.m. iNO (30 h) in piglets (n = 20). Plasma and urine were sampled during three periods (first and second 12 h periods, and finally a 6 h period). We measured urine volumes, plasma and urine electrolytes (UNa, UK, UCl), plasma creatinine and urea. We calculated creatinine clearance (Ccr), and fractional excretions of sodium and potassium (FENa, FEK) and urinary excretions of electrolytes (UENa, UEK, UECl). Haemodynamic data were recorded and renal tubular apoptosis detected. Results:, For the first 12 h, certain parameters significantly increased in the iNO group (mean ± SD): UNa (mmol L,1), 87.7 (±35.0) vs. 39.3 (±22.9), UCl (mmol L,1) 80.4 (±32.8) vs. 48.0 (±26.7), FENa (%) 2.1 (±0.8) vs. 0.7 (±0.5), FEK (%) 31.7 (±7.0) vs. 20.7 (±12.3), as well as UENa (mmol) 61.0 (±21.1) vs. 27.6 (±17.9) and UECl (mmol) 57.3 (24.5) vs. 37.6 (29.0). These changes were absent in the second and third periods of the study. Significant differences in percentage of apoptotic cell nuclei in the renal cortex and medulla were found after iNO exposure: 39% vs. 15%. Conclusion:, Exposure to 40 p.p.m. iNO in healthy anaesthetized piglets has a transient natriuretic effect that disappears after 12 h. We also found evidence of renal tubular apoptosis promotion after 30 h of iNO. [source] Twenty-four-hour non-invasive monitoring of systemic haemodynamics and cerebral blood flow velocity in healthy humansACTA PHYSIOLOGICA, Issue 1 2002M. DIAMANT ABSTRACT Acute short-term changes in blood pressure (BP) and cardiac output (CO) affect cerebral blood flow (CBF) in healthy subjects. As yet, however, we do not know how spontaneous fluctuations in BP and CO influence cerebral circulation throughout 24 h. We performed simultaneous monitoring of BP, systemic haemodynamic parameters and blood flow velocity in the middle cerebral artery (MCAV) in seven healthy subjects during a 24-h period. Finger BP was recorded continuously during 24 h by Portapres and bilateral MCAV was measured by transcranial Doppler (TCD) during the first 15 min of every hour. The subjects remained supine during TCD recordings and during the night, otherwise they were seated upright in bed. Stroke volume (SV), CO and total peripheral resistance (TPR) were determined by Modelflow analysis. The 15 min mean value of each parameter was assumed to represent the mean of the corresponding hour. There were no significant differences between right vs. left, nor between mean daytime vs. night time MCAV. Intrasubject comparison of the twenty-four 15-min MCAV recordings showed marked variations (P < 0.001). Within each single 15-min recording period, however, MCAV was stable whereas BP showed significant short-term variations (P < 0.01). A day,night difference in BP was only observed when daytime BP was evaluated from recordings in the seated position (P < 0.02), not in supine recordings. Throughout 24 h, MCAV was associated with SV and CO (P < 0.001), to a lesser extent with mean arterial pressure (MAP; P < 0.005), not with heart rate (HR) or TPR. These results indicate that in healthy subjects MCAV remains stable when measured under constant supine conditions but shows significant variations throughout 24 h because of activity. Moreover, changes in SV and CO, and to a lesser extent BP variations, affect MCAV throughout 24 h. [source] Characteristics of okadaic acid,induced cytotoxic effects in CHO K1 cellsENVIRONMENTAL TOXICOLOGY, Issue 6 2003C. Huynh-Delerme Abstract This article reports the results of investigations into the process of cell death induced in the Chinese hamster ovary cell K1 subclone (CHO K1) by okadaic acid (OA), a hydrophobic polyether produced by marine dinoflagellates. The IC50 was about 13 nM OA after 24 h of treatment, as determined using neutral red. With the MTT assay, the IC50 was 25 nM, although in this case 25% of the initial staining was still observed at 100 nM. Hoechst staining showed that mitotic figures accumulated at 12 nM OA after a 24- or 48-h treatment. In experiments limited to a 3-day treatment without changing the medium, CHO K1 cells were engaged in the death process at 50 nM OA after about 20 h and at 10 nM OA after 48 h. In many cells nuclear fragmentation that resulted in the apparent appearance of vesicles correlated with increasing cellular volume. But additional cell fragmentation was not observed with any treatment, and the chromatin material seemed to progressively disappear inside the cells. DNA fragmentation was analyzed by electrophoresis and with the TUNEL technique. With both techniques, the DNA was fragmented by 48 h in both 25 and 50 nM OA. Electrophoresis showed that both adherent and nonadherent cells were affected. Annexin-positive/ propidium iodide (PI),negative cells were rarely observed after OA treatment. Some were seen under the scanning cytometer after 20 h at 50 nM OA or after 48 h at 10 nM OA, but they were never detected by flow cytometry. Most of the time scanning cytometry showed either unstained cells or PI-positive (annexin-positive or -negative) cells (48 h, 50 nM, or 72 h, 10 nM). Flow cytometry cytograms showed two cell subpopulations: one composed of a majority of smaller cells, the other of larger cells. The larger cells markedly decreased with time and OA treatment (50 and 100 nM). Stained-cell counting showed that all cells that stained were both annexin- and PI positive and that most PI-positive cells were smaller. Ki67 antigen labeling showed the proliferative activity of CHO K1 cultures but also demonstrated the loss of this activity in smaller cells treated with 50 nM OA for 48 h. We concluded that in our culture conditions the main OA target within CHO K1 cultures was dividing cells. Our results suggest that cells with disturbed metaphase,anaphase enter apoptosis, leading to necrotic daughter cells. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 383,394, 2003 [source] Short-term cortisol infusion in the brachial artery, with and without inhibiting 11,-hydroxysteroid dehydrogenase, does not alter forearm vascular resistance in normotensive and hypertensive subjectsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2002S. H. M. Van Uum Abstract Background Vascular tone is increased in primary hypertension, and glucocorticoids affect vascular tone. Local cortisol availability is modulated by activity of 11,-hydroxysteroid dehydrogenase (11,-HSD). As this activity may be decreased in patients with primary hypertension, vascular sensitivity to cortisol may be increased in these patients. We studied the acute effect of cortisol on forearm vascular resistance (FVR) by infusing cortisol directly into the brachial artery, both with and without inhibition of 11,-HSD, in normotensive and hypertensive subjects. Design Twenty normotensive volunteers and 20 patients with primary hypertension participated in the study. After a 10-min infusion of vehicle (glucose 5%), cortisol was infused into the brachial artery in three stepwise increasing doses (3·5, 10·5 and 35 µg per 100 mL of forearm volume), each for 10 min. Next, the participants received placebo or 500 mg glycyrrhetinic acid (GA) orally, and 150 min later the same infusion schedule was repeated. Forearm vascular resistance was measured during the last 5 min of the infused vehicle and of each dose. Arterial and forearm venous plasma samples for measurement of cortisol and cortisone were taken at the end of the infusions of glucose 5% and the highest cortisol dose. Results In both normotensive and hypertensive subjects, neither the infusion of cortisol nor the administration of GA changed FVR. Also 2 h after the cortisol infusion there remained no change in FVR in both the normotensive and hypertensive groups who received placebo. Following the infusion of the highest cortisol dose, total plasma cortisone levels in the venous plasma were decreased compared with levels in the arterial plasma (36 ± 3 and 49 ± 4 nmol L,1, respectively, P < 0·05). The protein-bound venous cortisone was 37·1 ± 4·8 nmol L,1 during the vehicle compared with 23·9 ± 3·7 nmol L,1 during the cortisol infusion (P < 0·01), whereas the free cortisone level was not altered by the cortisol infusion. Conclusions In both normotensive and hypertensive subjects, high-dose cortisol infusion both with and without 11,-HSD inhibition did not change FVR either immediately or after 2 h. We could not demonstrate in vivo 11,-HSD activity in the forearm vascular tissues. When binding of cortisone to CBG is changed, e.g. during cortisol infusion, arterio-venous changes in cortisone cannot reliably be used to assess (alterations in) local 11,-HSD activity. [source] Oxidative and excitotoxic insults exert differential effects on spinal motoneurons and astrocytic glutamate transporters: Implications for the role of astrogliosis in amyotrophic lateral sclerosisGLIA, Issue 2 2009Chrissandra J. Zagami Abstract In amyotrophic lateral sclerosis (ALS) non-neuronal cells play key roles in disease etiology and loss of motoneurons via noncell-autonomous mechanisms. Reactive astrogliosis and dysfunctional transporters for L -glutamate [excitatory amino acid transporters, (EAATs)] are hallmarks of ALS pathology. Here, we describe mechanistic insights into ALS pathology involving EAAT-associated homeostasis in response to a destructive milieu, in which oxidative stress and excitotoxicity induce respectively astrogliosis and motoneuron injury. Using an in vitro neuronal-glial culture of embryonic mouse spinal cord, we demonstrate that EAAT activity was maintained initially, despite a loss of cellular viability induced by exposure to oxidative [3-morpholinosydnonimine chloride (SIN-1)] and excitotoxic [(S)-5-fluorowillardiine (FW)] conditions. This homeostatic response of EAAT function involved no change in the cell surface expression of EAAT1/2 at 0.5,4 h, but rather alterations in kinetic properties. Over this time-frame, EAAT1/2 both became more widespread across astrocytic arbors in concert with increased expression of glial fibrillary acidic protein (GFAP), although at 8,24 h there was gliotoxicity, especially with SIN-1 rather than FW. An opposite picture was found for motoneurons where FW, not SIN-1, produced early and extensive neuritic shrinkage and blebbing (,0.5 h) with somata loss from 2 h. We postulate that EAATs play an early homeostatic and protective role in the pathologic milieu. Moreover, the differential profiles of injury produced by oxidative and excitotoxic insults identify two distinct phases of injury which parallel important aspects of the pathology of ALS. © 2008 Wiley-Liss, Inc. [source] Metabolic Acidosis Stimulates RANKL RNA Expression in Bone Through a Cyclo-oxygenase-Dependent Mechanism,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2003Kevin K Frick Abstract Metabolic acidosis inhibits osteoblastic bone formation and stimulates osteoclastic resorption. To determine whether acidosis alters expression of RNA for the osteoclastic differentiation factor RANKL, mouse calvariae were incubated in neutral or physiologically acidic media. Acidosis resulted in a significant cyclo-oxygenase-dependent increase in RANKL RNA levels, which would be expected to induce the associated increase in bone resorption. Introduction: Metabolic acidosis increases net calcium efflux from bone, initially through physicochemical mechanisms and later through predominantly cell-mediated mechanisms. Acidosis decreases osteoblastic bone formation and increases osteoclastic resorption. The growth and maturation of osteoclasts, derived from hematopoietic precursors in the monocyte/macrophage lineage, are dependent on the interplay of a number of factors. Commitment of pre-osteoclasts to osteoclasts is induced by the interaction of the osteoclastic cell-surface receptor RANK with a ligand expressed by osteoblasts, RANKL. The RANK/RANKL interaction not only initiates a differentiation cascade that culminates in mature bone-resorbing osteoclasts but also increases osteoclastic resorptive capacity and survival. Methods: To test the hypothesis that metabolic acidosis increases expression of RANKL, we cultured neonatal mouse calvariae in acidic (initial medium pH ,7.1 and [HCO3,] ,11 mM) or neutral (initial medium pH ,7.5 and [HCO3,] ,25 mM) medium for 24 and 48 h. We determined the relative expression of RANKL RNA by reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitated the expression by Northern analysis. Results: In this model of metabolic acidosis, there was significantly increased expression of RANKL RNA at both 24 (2-fold) and 48 h (5-fold) compared with respective controls. Net calcium efflux from bone was also increased in acidic medium compared with control medium. At 48 h, net calcium efflux correlated directly with RANKL expression (r = 0.77, n = 15, p < 0.001). Inhibition of prostaglandin synthesis with indomethacin blocked the acid-induced increase in RANKL RNA as well as the increased calcium efflux. Conclusions: Metabolic acidosis induces osteoblastic prostaglandin synthesis, followed by autocrine or paracrine induction of RANKL. This increase in RANKL would be expected to augment osteoclastic bone resorption and help explain the increase in cell-mediated net calcium efflux. [source] Salvianolic acid B attenuates plasminogen activator inhibitor type 1 production in TNF-, treated human umbilical vein endothelial cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2005Zhe Zhou Abstract Plasminogen activator inhibitor type 1 (PAI-1), which plays a role in the development of atherosclerosis, is produced by endothelial cells following stimulation with various inflammatory cytokines such as tumor necrosis factor (TNF-,). In the present study, we investigated the effects of a potent water-soluble antioxidant, salvianolic acid B (SalB; derived from the Chinese herb, Salviamiltiorrhiza), on the expression of PAI-1 in TNF-,-treated human umbilical vein endothelial cells (HUVECs). We found that SalB inhibited TNF-,-induced PAI-1 mRNA production and protein secretion in HUVECs. Treatment with SalB (0.05 and 0.15 µM) notably attenuated TNF-, induced expression of PAI-1 to 90.5% and 74.6%, respectively, after 12 h, and to 75.1% and 64.2%, respectively, after 18 h. We also observed a dose-dependent decrease in PAI-1 protein production in the presence of SalB. We then used pathway inhibitors to investigate which step of the TNF-, induced signaling pathway was targeted by SalB. We found that the c-Jun N-terminal kinase (JNK) inhibitor, SP600125, increased the inhibitory effects of SalB on TNF-,-induced PAI-1 secretion, whereas the nuclear factor-,B (NF-,B) inhibitor, emodin, and the extracellular signal-regulated kinase (ERK) inhibitor, PD98059, did not. A gel shift assay further showed that SalB inhibited the TNF-,-activated NF-,B and AP-1 DNA binding activities in a dose-dependent manner. Collectively, these results indicate that the NF-,B and ERK-AP-1 pathways are possible targets of SalB in the regulation of TNF-,-stimulated PAI-1 production in HUVECs. © 2005 Wiley-Liss, Inc. [source] On variable bandwidth selection in local polynomial regressionJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 3 2000Kjell Doksum The performances of data-driven bandwidth selection procedures in local polynomial regression are investigated by using asymptotic methods and simulation. The bandwidth selection procedures considered are based on minimizing ,prelimit' approximations to the (conditional) mean-squared error (MSE) when the MSE is considered as a function of the bandwidth h. We first consider approximations to the MSE that are based on Taylor expansions around h=0 of the bias part of the MSE. These approximations lead to estimators of the MSE that are accurate only for small bandwidths h. We also consider a bias estimator which instead of using small h approximations to bias naïvely estimates bias as the difference of two local polynomial estimators of different order and we show that this estimator performs well only for moderate to large h. We next define a hybrid bias estimator which equals the Taylor-expansion-based estimator for small h and the difference estimator for moderate to large h. We find that the MSE estimator based on this hybrid bias estimator leads to a bandwidth selection procedure with good asymptotic and, for our Monte Carlo examples, finite sample properties. [source] ADAMTS-13 activity in plasma is rapidly measured by a new ELISA method that uses recombinant VWF-A2 domain as substrateJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2004J. L. Whitelock Summary., The metalloprotease ADAMTS-13 cleaves von Willebrand factor (VWF) at the Y842/M843 peptide bond located in the A2 domain. Measurement of ADAMTS-13 activity is a clinical utility for thrombotic diseases, but the current assays used for diagnostic and clinical research are non-physiological and time consuming. We have expressed in bacteria a recombinant VWF-A2 peptide (aa 718,905) that contains both a 6xHis tag at the N-terminal end and a Tag-100 epitope at the C-terminal end. Diluted plasma was mixed with the VWF-A2 peptide and digestion was allowed to proceed in a Ni2+ -coated microtiter well plate for 2 h. The immobilized Ni2+ captures the VWF-A2 peptide by its 6xHis tag and cleavage of the A2 peptide is measured by the removal of the C-terminus fragment of the A2 peptide that contains the Tag-100. The cleavage activity for this assay was defined by the low detection of A2 peptide containing the Tag-100 epitope by the antiTag-100 monoclonal antibody. The assay was completed in <5 h. We then used the assay to analyze ADAMTS-13 activity in plasma from 39 healthy donors and 16 samples from patients diagnosed as thrombotic thrombocytopenic purpura. The average of enzyme activity ±,SEM for normal plasmas diluted 1 : 50 was 40 ± 4.2% while the value obtained for the patients was 2.4 ± 0.7%. These results were validated by a traditional long incubation assay (24 h). Our assay provides significant advantages over currently used assays because it is quicker, reproducible, cost effective and measures ADAMTS-13 activity under physiological and non-denaturing conditions. This assay is clinically useful and significant in measuring ADAMTS-13 activity in plasma. [source] TERM STRUCTURES OF IMPLIED VOLATILITIES: ABSENCE OF ARBITRAGE AND EXISTENCE RESULTSMATHEMATICAL FINANCE, Issue 1 2008Martin Schweizer This paper studies modeling and existence issues for market models of stochastic implied volatility in a continuous-time framework with one stock, one bank account, and a family of European options for all maturities with a fixed payoff function h. We first characterize absence of arbitrage in terms of drift conditions for the forward implied volatilities corresponding to a general convex h. For the resulting infinite system of SDEs for the stock and all the forward implied volatilities, we then study the question of solvability and provide sufficient conditions for existence and uniqueness of a solution. We do this for two examples of h, namely, calls with a fixed strike and a fixed power of the terminal stock price, and we give explicit examples of volatility coefficients satisfying the required assumptions. [source] The Monitor project: the search for transits in the open cluster NGC 2362MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008Adam A. Miller ABSTRACT We present the results of a systematic search for transiting planets in a ,5 Myr open cluster, NGC 2362. We observed ,1200 candidate cluster members, of which ,475 are believed to be genuine cluster members, for a total of ,100 h. We identify 15 light curves with reductions in flux that pass all our detection criteria, and six of the candidates have occultation depths compatible with a planetary companion. The variability in these six light curves would require very large planets to reproduce the observed transit depth. If we assume that none of our candidates are, in fact, planets then we can place upper limits on the fraction of stars with hot Jupiters (HJs) in NGC 2362. We obtain 99 per cent confidence upper limits of 0.22 and 0.70 on the fraction of stars with HJs (fp) for 1,3 and 3,10 d orbits, respectively, assuming all HJs have a planetary radius of 1.5RJup. These upper limits represent observational constraints on the number of stars with HJs at an age ,10 Myr, when the vast majority of stars are thought to have lost their protoplanetary discs. Finally, we extend our results to the entire Monitor project, a survey searching young, open clusters for planetary transits, and find that the survey as currently designed should be capable of placing upper limits on fp near the observed values of fp in the solar neighbourhood. [source] A search for starlight reflected from HD 75289bMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2003Christopher Leigh ABSTRACT We have used a Doppler tomographic analysis to conduct a deep search for the starlight reflected from the planetary companion to HD 75289. In four nights on VLT(UT2)/UVES in 2003 January, we obtained 684 high-resolution echelle spectra with a total integration time of 26 h. We establish an upper limit on the geometric albedo of the planet p < 0.12 (to the 99.9 per cent significance level) at the most probable orbital inclination i, 60°, assuming a grey albedo, a Venus-like phase function and a planetary radius Rp= 1.6 RJup. We are able to rule out some combinations of the predicted planetary radius and atmospheric albedo models with high, reflective cloud decks. [source] The intraoperative use of recombinant FVIIa in child with hemophilia A with antibodiesPEDIATRIC ANESTHESIA, Issue 8 2007DUSICA SIMIC MD Summary Patients with hemophilia A that developed inhibitors to FVIII represent a problem for bleeding control especially during surgical procedures. We report the use of bolus injections of rFVIIa during one intervention that included synoviectomy on the right knee, cholecystectomy and appendicectomy in a child with high titer of inhibitors to FVIII. rFVIIa was administered at the start (120 ,g·kg,1) and then every 2 h (90 ,g·kg,1) during the procedure. ,-aminocapronic acid was also administered as an antifibrinolytic every 3 h. We monitored aPTT (activated partial thromboplastin time) and PT (prothrombin time) and they were within reference values. Surgery lasted 7 h without significant hemorrhage. Postoperatively the dose of rFVIIa was slowly reduced and after ten days the patient was discharged home in good condition. In our case rFVIIa helped a child with hemophilia A with antibodies to undergo major surgery but each case should be treated individually and the cost of rFVIIa has also to be taken into account. [source] Prevention of vomiting after strabismus surgery in children: dexamethasone alone versus dexamethasone plus low-dose ondansetronPEDIATRIC ANESTHESIA, Issue 5 2001FRCP(C), William M. Splinter MD Background: Postoperative vomiting is a common complication after strabismus surgery. The combination of dexamethasone and ondansetron decreases vomiting after strabismus surgery, while dexamethasone alone decreases vomiting after tonsillectomy in children. We compared the effect of dexamethasone alone to ondansetron plus dexamethasone on postoperative vomiting among children undergoing strabismus surgery. Methods: Healthy children, aged 2,14 years, who were undergoing strabismus surgery were entered into this randomized, blocked and stratified study. Patients were administered 0.5 mg·kg,1 midazolam p.o., 20,30 min preoperatively when indicated. The patients had an intravenous induction with 2.5,3.5 mg·kg,1 propofol or an inhalation induction of anaesthesia with halothane and N2O. All patients were given 20 ,g·kg,1 atropine i.v. Study drugs were administered in a double-blind fashion. Both groups received 150 ,g·kg,1 dexamethasone i.v. Group D patients received placebo and group OD received 50 ,g·kg,1 of ondansetron i.v. Anaesthesia was maintained with halothane and N2O. Postoperative fluid, vomiting and pain management were standardized. Patients were followed for 24 h. We studied 193 patients with 111 patients in the OD group. Demographic data were similar. Results: The overall incidence of vomiting was 23%; in group D and 5%; in group OD (P < 0.001). Each episode of vomiting increased the in-hospital length of stay by 29 min (P < 0.001). Conclusions: There was a remarkably low incidence of postoperative vomiting of 5%; with the combination of dexamethasone plus a low-dose of ondansetron which more effectively decreased vomiting after strabismus surgery in children when compared with dexamethasone alone. [source] Ultraviolet-A and -B Differentially Modify the Tyrosine-Kinase Profile of Human Keratinocytes and Induce the Expression of Arg,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2008Gabriele Klosner To investigate the expression profile of protein tyrosine kinases (PTKs) in normal human epidermal keratinocytes (NHEK) in response to UVA and UVB we employed a reversed transcriptase polymerase chain reaction (PCR) approach using degenerate primers derived from the conserved catalytic domain of PTKs. Quantitative real-time PCR with specific primers was used to confirm the influence of UV on the expression of the identified PTKs. Arg (Abelson-related gene, Abl2) was the PTK with the highest prevalence (30% of all PTKs) and UVA led to a further induction of Arg expression reaching nine-fold mRNA baseline expression at 17 h after irradiation. UVB was followed by an initial downregulation and a subsequent increase in Arg mRNA reaching five-fold baseline levels after 24 h. We conclude that UVA and UVB differentially modify the expression of PTKs in NHEK, and that Arg appears to have a major role in the response of keratinocytes to UV. These results provide a basis for further studies of PTK in UV-induced signaling that regulates protective responses, cell growth and carcinogenesis in the skin. [source] Evaluating the cytotoxic doses of narrowband and broadband UVB in human keratinocytes, melanocytes, and fibroblastsPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 3 2008Tae-Ho Cho Summary Background: No comparative and simultaneous in vitro studies have been performed to determine the cytotoxic dose of narrowband UVB (NBUVB) and broadband UVB (BBUVB) for keratinocytes, melanocytes, and fibroblasts. Culture medium was often replaced with phosphate-buffered saline (PBS) before UV irradiation; however, its amount differed across studies. We determined the cytotoxic doses of NBUVB and BBUVB and tested for changes in viability according to the amount of PBS. Methods: We exposed cultured human keratinocytes, melanocytes, and fibroblasts to ultraviolet light in the range 12.5,1000 mJ/cm2 for NBUVB and 1.25,100 mJ/cm2 for BBUVB. The viability was assessed after 24 h. We also determined changes in viability at cytotoxic doses according to the amount of PBS (40, 80, and 120 ,l/well in a 96-well plate). Results: Cytotoxicity was observed at doses of 100, 200, and 400 mJ/cm2 for NBUVB and 5, 10, and 25 mJ/cm2 for BBUVB in keratinocytes, melanocytes, and fibroblasts, respectively. At cytotoxic doses, there was no change in viability according to the amount of PBS. Conclusions: Fibroblasts are more resistant to UVB irradiation, irrespective of the amount of NBUVB and BBUVB, than keratinocytes and melanocytes. The amount of PBS during irradiation had no effect on viability. [source] Dietary phytase increases the true absorption and endogenous fecal excretion of zinc in growing pigs given a corn-soybean meal based dietANIMAL SCIENCE JOURNAL, Issue 1 2009Gyo-Moon CHU ABSTRACT We investigated the effect of dietary phytase on the true absorption and endogenous fecal excretion of zinc (Zn) using 67Zn in growing pigs given a corn-soybean meal based diet. Ten crossbred barrows were fed the control diet containing 90-mg/kg Zn, 2.3-g/kg phytate-phosphorus and 3.7-g/kg non-phytate-phosphorus or the phytase diet containing similar amounts of Zn and phytate-phosphorus, and 1.4-g/kg non-phytate-phosphorus with 750-PU/kg phytase for 12 h/day. On day 6, the pigs were given 200 g of the corresponding diet labeled by 67Zn for 2 h. We measured feed intake, fecal Zn concentration and 67Zn abundance for the determination of apparent absorption, true absorption and endogenous fecal excretion of Zn. Although the apparent absorption of Zn did not significantly differ between the dietary groups, the phytase group had significantly more (P < 0.05) true absorption of Zn than the control group. The endogenous fecal excretion of Zn tended to be more (P = 0.07) in the phytase group than in the control group. These results suggest that dietary phytase improves Zn bioavailability through increasing the true absorption of Zn in growing pigs, which results in stimulating the endogenous fecal excretion of Zn when dietary Zn satisfies its requirement. [source] Supplementary oxygen and temperature management during live transportation of greenlip abalone, Haliotis laevigata (Donovan, 1808)AQUACULTURE RESEARCH, Issue 7 2009Erin J Bubner Abstract Live greenlip abalone, Haliotis laevigata, are highly valued in Australian export markets with demand increasingly being met with cultured stock. Live transportation of abalone requires the maintenance of favourable conditions within transport containers for periods exceeding 35 h. We examined the combined effects of temperature regulation (ice provision) and of supplemental oxygen (60% and 100% concentrations) on mortality rates of abalone over 7 days following a 35-h simulated live-transport experiment. We also examined the physiological condition of greenlip abalone (oxygen consumption rate, haemolymph pH and weight) during the simulation experiment. The provision of ice and supplementary oxygen reduced abalone mortalities. Omission of ice and supplementary oxygen during the transport simulation resulted in mortality rates ranging from 70% to 100%. The addition of ice to containers with ambient oxygen concentrations decreased average mortality rates by 50%. While supplementary oxygen further reduced these rates, the provision of both ice and 100% oxygen was by far the most effective combination, reducing mortalities to between 2% and 6%. Supplementary oxygen increased oxygen consumption rates of abalone above those transported at ambient oxygen concentrations. Live-transport decreased haemolymph pH in all treatments but was most pronounced in treatments without ice or supplementary oxygen. On average, abalone lost 7,13% of their weight during the simulation but this loss was independent of transport treatment. [source] "Setting paint" analogy for the hydrophobic self-association of tropoelastin into elastin-like hydrogelBIOPOLYMERS, Issue 5 2009Christoph Naumann Abstract Alkaline tropoelastin solutions (pH 11) were optically clear at low temperatures, but a firm gel formed when the temperature was raised to 37°C. Reversion to a clear solution took place if the temperature was lowered to below 20°C within less than 2 h, but not if 37°C was maintained for several hours. The precipitated elastin-like hydrogel thus formed did not visually redissolve at low temperatures. Tropoelastin hydrogel was stable to subsequent washings with alkaline solution at 37°C, but at 4°C some hydrogel redissolved showing that association is at least partly reversible. Washing the hydrogel with neutral 8M urea solution at 4°C dissolved less than 10% of tropoelastin in 24 h. We characterized this phenomenon by combining temperature-controlled light microscopy analysis, 1H NMR spectroscopy (temperature, diffusion, and relaxation time studies), and UV-absorption-based concentration measurements. The self-association of tropoelastin at pH 11 is due to hydrophobic interactions in an emulsion-like system in which the spherules coalesce in a manner like a water-based latex paint that forms a durable hydrophobic sheet as water and the organic solvent evaporate. In the present case, the sedimentation and entanglement of the tropoelastin porous sheets means that reverse dissolution is a kinetically slow process. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 321,330, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Xeroderma pigmentosum: the role of phototestingBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2000N. Stone We report three patients newly diagnosed as having xeroderma pigmentosum (XP). Previous photobiological studies have implicated ultraviolet (UV) B as the activating waveband in XP, causing a delayed and prolonged erythemal response. This characteristic reaction pattern has been used as a quick screening test in patients suspected of having XP, while awaiting confirmatory DNA repair studies. Two of our patients showed no abnormal erythemal responses, and one showed severe photosensitivity from 330 to 400 nm but normal UVB responses, with a peak erythema at 24 h. We conclude that the erythemal responses in XP are highly variable and cannot be considered as a reliable screening test in the diagnosis of XP. [source] Pharmacokinetic Study of a Gallium-porphyrin Photo- and Sono-sensitizer, ATX-70, in Tumor-bearing MiceCANCER SCIENCE, Issue 9 2001Kazuaki Sasaki The tissue distribution of a gallium-porphyrin photo- and sono-sensitizer, 7,12-bis(l-decyloxy-ethyl)-Ga(III)-3,8,13,17-tetramethylporphyrin-2,18-dipropionyldiaspartic acid, ATX-70, was phar-niacokinetically examined in tumor-bearing mice. The drug was administered intravenously to CDF1mice implanted with Colon 26 carcinoma. Blood and tissue samples were collected for up to 72 h after administration. The drug concentration was determined by high-performance liquid chromatography (HPLC) with fluorescence detection. ATX-70 was found to accumulate in tumors at a relatively high concentration that peaked between 2 h and 6 h after administration. However, modest concentrations of ATX-70 also remained in healthy tissues for up to 6 h. We examined the distribution of ATX-70 in the tumor in comparison with other tissues from the viewpoint of minimizing possible side effects of laser or ultrasound exposure while maintaining the treatment effect. About 24 h after administration, the tumor/plasma concentration ratio peaked, and relatively high tumor/skin and tumor/muscle concentration ratios were seen. [source] | |||||||||||||||||||