bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidation of Human Catalase by Singlet Oxygen in Myeloid Leukemia Cells‡
Authors: Lledías Fernando , Hansberg Wilhelm 
Published: January 2008

AbstractCatalases are oxidized by singlet oxygen giving rise to more acidic conformers detected in zymograms after electrophoresis in polyacrylamide gels. This shift in catalase mobility can be indicative of singlet oxygen production in vivo. Catalase from human cells, as from many organisms, is susceptible to in vitro modification by singlet oxygen. Human myeloid leukemia (U937) cells were treated under different stress conditions and catalase activity and its electrophoretic mobility was monitored. The U937 cells were found to have high levels of catalase activity, as compared to cultured fibroblasts, and to be very resistant to oxidative stress. Hydrogen peroxide did not modify the electrophoretic mobility of catalase, even at doses that produced cell damage. Conditions that primarily generate superoxide, such as treatment with paraquat or heat shock, also failed to modify the enzyme. In contrast, photosensitization reactions using rose Bengal gave rise to a more acidic conformer of catalase. Singlet oxygen quenchers prevented catalase modification by rose Bengal and light. The growth medium had a photosensitizing activity. Catalase was not modified in cells illuminated in phosphate buffer but was modified in cells illuminated in phosphate buffer containing riboflavin. Intense light per se also generated a slight shift in the electrophoretic mobility of catalase. Ultraviolet light (350 or 366 nm) did cause a change in catalase, but to a less acidic catalase conformer, indicating other modifications of the enzyme. The main effect of photosensitization with methylene blue was crosslinking of the enzyme, although some shift to acidic conformers was observed at a low concentration of the photoactive compound. Results indicate that catalase can be modified by singlet oxygen generated intracellulary, even though the enzyme is predominantly inside peroxisomes. Under some photosensitization conditions, catalase modification can be used as a marker to detect intracellular singlet oxygen.
Spectral Irradiance in Pond Water: Influence of Water Chemistry
Authors: Crump D. , Lean D. , Berrill M. , Coulson D. , Toy L. 
Published: January 2008

AbstractKnowing the depth of UV penetration in ponds and the chemical variables that control underwater spectral irradiance is a prerequisite to predicting the influence of UV on amphibians and other pond organisms. The present study found that over 99% of UVB (280–315 nm) radiation was attenuated in the top 10–20 cm of ponds sampled on the edge of the Canadian Shield near Peterborough, Ontario. While the principal attenuating substance was, as in lakes, dissolved organic carbon (DOC), neither DOC nor DOC fluorescence were useful predictors of the attenuation coefficients other than the observation that all values of DOC were high and all attenuation coefficients were also high. The lack of a reliable relationship between DOC and attenuation resulted from differences throughout the season in the fraction of the DOC capable of absorbing radiation (chromophores) and the fraction capable of fluorescing (fluorophores). Attenuation was higher than predicted from DOC during springtime when amphibians lay their eggs. Absorbance coefficients measured using a spectrophotometer proved to be reliable predictors of both UVB and UVA attenuation coefficients measured in the ponds with a spectro‐radiometer. While DOC provides an effective sun screen against the direct damage of UV radiation, the high attenuation means that the photochemical activity spread over at least 15 m in the ocean is confined to only a few centimeters in ponds.
Activation of Epidermal Akt by Diverse Mouse Skin Tumor Promoters
Authors: Lu Jerry , Rho Okkyung , Wilker Erik , Beltran Linda , DiGiovanni John 
Published: January 2008

Abstract
Akt is a serine/threonine kinase involved in a variety of cellular responses, including cell proliferation and cell survival. Recent studies from our laboratory suggest that Akt signaling may play an important role in skin tumor promotion. To explore this premise, we examined epidermal Akt activation and signaling in response to chemically diverse skin tumor promoters. Mice received single or multiple applications of 12-O-tetradecanoylphorbol-13-acetate (TPA), okadaic acid, or chrysarobin. All three tumor promoters were able to activate epidermal Akt as early as 1 h after treatment. Activation of Akt following tumor promoter treatment led to enhanced downstream signaling, including hyperphosphorylation of glycogen synthase kinase-3β and Bad. Structure activity studies with phorbol ester analogues revealed that the magnitude of activation paralleled tumor-promoting activity. In cultured primary keratinocytes, TPA treatment also led to activation of Akt. Activation of the epidermal growth factor receptor (EGFR) seemed to underlie the ability of TPA to activate Akt as both PD153035, an inhibitor of EGFR, and GW2974, a dual-specific inhibitor of both EGFR and erbB2, were able to effectively reduce TPA-induced Akt phosphorylation as well as TPA-stimulated EGFR and erbB2 tyrosine phosphorylation in a dose-dependent manner. Furthermore, inhibition of protein kinase C (PKC) activity blocked TPA-stimulated heparin-binding EGF production and EGFR transactivation. Inhibition of PKC also led to a decreased association of Akt with the PP2A catalytic subunit, leading to increased Akt phosphorylation. However, combination of EGFR inhibitor and PKC inhibitor completely abrogated TPA-induced activation of Akt. Collectively, the current results support the hypothesis that elevated Akt activity and subsequent activation of downstream signaling pathways contribute significantly to skin tumor promotion. In addition, signaling through the EGFR via EGFR homodimers or EGFR/erbB2 heterodimers may be the primary event leading to Akt activation during tumor promotion in mouse skin. (Mol Cancer Res 2007;5(12):1342–52)
Ataxia-Telangiectasia Mutated Is Not Required for p53 Induction and Apoptosis in Irradiated Epithelial Tissues
Authors: Gurley Kay E. , Kemp Christopher J. 
Published: January 2008

Abstract
The ataxia-telangiectasia mutated (Atm) protein kinase is a central regulator of the cellular response to DNA damage. Although Atm can regulate p53, it is not known if this Atm function varies between tissues. Previous studies showed that the induction of p53 and apoptosis by whole-body ionizing radiation varies greatly between tissue and tumor types, so here we asked if Atm also had a tissue-specific role in the ionizing radiation response. Irradiated Atm-null mice showed impaired p53 induction and apoptosis in thymus, spleen, and brain. In contrast, radiation-induced p53, apoptosis, phosphorylation of Chk2, and G2-M cell cycle arrest were slightly delayed in Atm−/− epithelial cells of the small intestine but reached wild-type levels by 4 h. Radiation-induced p53 and apoptosis in Atm−/− hair follicle epithelial cells were not impaired at any of the time points examined. Thus, Atm is essential for radiation-induced apoptosis in lymphoid tissues but is largely dispensable in epithelial cells. This indicates that marked differences in DNA damage signaling pathways exist between tissues, which could explain some of the tissue-specific phenotypes, especially tumor suppression, associated with Atm deficiency. (Mol Cancer Res 2007;5(12):1312–8)
Internet Use and Abuse in an Adolescent Population in Athens: Associations with Psychological Profile and Lifestyle of Users
Authors: Tripodaki Elli , Kormas Georgios , Konstantoulaki Eleftheria , Andrie Elisabeth , Nassis Georgios , Freskou Aliki , Sfiri Maria , Georgouli Helen , Tsitsika Artemis , Constantopoulos Andreas 
Published: January 2008

INTRODUCTION:
Use of the Internet has become very popular among youth, but phenomena of Web abuse with negative physical and psychosocial consequences have emerged.

OBJECTIVE:
The researchers' goal was to study Internet use and abuse by Greek adolescents and to identify the psychological profile and lifestyle of users. Intervention attempts will also be designed and discussed.

METHODS:
An Athens adolescent population representative sample of 315 (164 boys, 151 girls) high school students (mean age: 15 years) were included in the study. For Internet-addiction diagnosis, an international tool (Young's Internet Addiction Test questionnaire) was used. The Strengths and Difficulties Questionnaire was applied to screen for emotional and behavioral problems. Physical activity and physical fitness were also assessed with appropriate questions. Correlation and x2 statistics were performed by using SPSS (SPSS Inc, Chicago, IL).

RESULTS:
According to the results, 167 (53.4%) of 315 adolescents were using the Internet for &gt;1 year, 82 (26%) of 315 reported daily use, and 25 (8%) of 315 reported &gt;20 hours' use weekly. Boys were spending significantly more time using the Internet than girls (P &lt; .05). According to Young's Questionnaire scoring, no youngster in our sample was addicted. However, in 28 (9.4%) of 315 adolescents, Young's Questionnaire scoring was suggestive of occasional or frequent problems of Internet overuse. The most frequent reason for using the Internet was games (P &lt; .05), and 18 (5.8%) of 315 children in our sample were cyberbullying victims. There was a positive correlation of Internet use and hyperactivity according to the Strengths and Difficulties Questionnaire results (P &lt; .05). Positive correlations were also noted for Internet use and delinquency (P &lt; .001) as well as dysfunctional peer relationships (P &lt; .001).

CONCLUSIONS:
Use of the Internet is popular among Greek youth, and it can be related to psychosocial problems if overused.
DETECTION AND MOLECULAR SEROTYPING OF GROUP B STREPTOCOCCUS IN FATAL NEONATAL PNEUMONIA IN CHINA
Authors: Deng Jianghong , Yang Yonghong 
Published: January 2008

INTRODUCTION: Group B Streptococcus (GBS) has been recognized as an important pathogen in neonatal infectious disease. However, there are few data on the prevalence of neonatal GBS infection in China.
OBJECTIVE: Our aim was to estimate the infection rate of GBS in neonatal pneumonia in China and identify distribution of the GBS serotype.
METHODS: We retrospectively studied 200 children with fatal neonatal pneumonia who died between 1953 and 2004; 34 fatal neonatal cases without any infectious disease were used as a control group. Paraffin-embedded lung tissues were collected for total genomic DNA extraction. Polymerase chain reaction (PCR) and Southern blotting were used for GBS detection and molecular serotyping.
RESULTS: (1) The positive rate of GBS in the pneumonia group was significantly higher than that in the control group (PCR: 26% vs 3% [P &lt; .01]; Southern blot: 65% vs 18% [P &lt; .01]). (2) The positive rate in neonates younger than 7 days was significantly higher than that in neonates older than 7 days (PCR: 37% vs 13% [P &lt; .01]; Southern blot: 72% vs 52% [P &lt; .05]). (3) Risk factors were identifiable for most GBS-positive cases. (4) In the pneumonia group, 22 GBS-positive cases were serotypeable: 7 cases were identified as serotype Ia, 6 cases were serotype III, 5 cases were serotype II, and 1 case was serotype Ib.
CONCLUSIONS: In China, GBS is an important pathogen in fatal neonatal pneumonia, especially in early-onset cases. Serotypes Ia, III, and II were the most common serotypes identified.
ASSESSMENT OF BONE MINERAL DENSITY AND MARKERS OF BONE TURNOVER IN CHILDREN UNDERGOING LONG-TERM ORAL ANTICOAGULANT THERAPY
Authors: Avgeri Maria , Platokouki Helen , Papadopoulou Anna , Douros Kostas , Rammos Spyridon , Nicolaidou Polyxeni , Aronis Sophia 
Published: January 2008

INTRODUCTION: Oral anticoagulants antagonize vitamin K action and potentially impair the carboxylation of osteocalcin, a protein that is essential for normal bone matrix formation.
OBJECTIVE: Our aim was to evaluate bone mineral density (BMD) and bone-turnover markers in 23 children who were undergoing long-term oral anticoagulant therapy (median age: 4 years) and 25 age- and gender-matched controls.
METHODS: BMD (characterized as a z score) of the lumbar spine was assessed by using dual energy radiograph absorptiometry. Osteoblast (bone alkaline phosphatase, osteocalcin, and amino-terminal procollagen 1 extension peptide) and osteoclast (urinary calcium and deoxypyridinoline and serum cross-linked C telopeptide) activity markers were measured. Vitamin D (25-hydroxy vitamin D, parathyroid hormone, whole and ionized calcium, phosphorus, and magnesium) and vitamin K (factors II, VII, IX, and X, protein C, protein S, and undercarboxylated osteocalcin [Glu-Oc]) statuses were determined.
RESULTS: Patients presented with higher levels of Glu-Oc, parathyroid hormone, and bone-resorption markers and lower levels of bone-formation markers and 25-hydroxy vitamin D; 52% of them showed signs of osteopenia (−1.0 &gt; BMD z score &gt; −2.5). Statistical analysis demonstrated that anticoagulant therapy was an independent predictor of alterations in Glu-OC, osteocalcin, bone alkaline phosphatase, amino-terminal procollagen 1 extension peptide, and serum cross-linked C telopeptide levels.
CONCLUSIONS: Long-term use of coumarin derivatives may cause osteopenia in children with the risk of developing osteoporosis later in life.
HIGH SEROPREVALENCE OF HUMAN METAPNEUMOVIRUS INFECTION IN CHILDREN IN THE CHONGQING, CHINA, AREA
Authors: Zhao Xiaodong , Qin Zhang 
Published: January 2008

INTRODUCTION: Human metapneumovirus (hMPV), first isolated in 2001 in the Netherlands, was identified as a respiratory etiologic agent in a variety of regions. A number of reports have described evidence of hMPV infection on mainland China. However, the description of the seroepidemiology of hMPV infection remains limited.
OBJECTIVE: We aimed to define the seropositivity of hMPV immunoglobulin G (IgG) antibodies in different age groups of children in Chongqing, China.
METHODS: The specificity of the enzyme-linked immunosorbent assay was first validated by using respiratory syncytial virus (RSV)-infected cell lysates subtracted sera and Western blotting based on anti-hMPV animal serum. This assay was subsequently used to determine the presence of IgG antibodies to hMPV and RSV in 325 serum samples from children aged 0 to 6 years.
RESULTS: There was no cross-reaction between the hMPV and RSV enzyme-linked immunosorbent assays observed in our system. Seropositivity of anti-hMPV IgG antibodies in children aged 0 to 5 months was 74.5%, 64% for children aged 6 to 11 months, 72.7% for children aged 12 to 23 months, 87.1% for children aged 24 to 35 months, and 90.3% for children 3 to 6 years old, respectively. The seropositivity of hMPV and RSV was considerably similar in almost all age groups.
CONCLUSIONS: hMPV seems to be a common and important respiratory pathogen in Chongqing's children. Almost all individuals had been exposed to hMPV by the age of 6 years.
Analysis of neuronal cell death in the cerebral cortex of H-Tx rats with compensated hydrocephalus
Authors: Nonaka Yasuomi , Miyajima Masakazu , Ogino Ikuko , Nakajima Madoka , Arai Hajime 
Published: January 2008

Object
Some cases of compensatory hydrocephalus have been reported in which cognitive deficiency progresses despite the absence of progressive ventricular dilation. In this study, the differentially expressed genes in compensated hydrocephalic H-Tx rat cortices were determined. A molecular mechanism that induces neuronal death in the cerebral cortex of compensated hydrocephalus is proposed.

Methods
The cerebral cortices of 8-week-old H-Tx rats with spontaneously arrested hydrocephalus (hH-Tx) and nonhydrocephalic H-Tx (nH-Tx) control rats were subjected to cDNA microarray analysis followed by canonical pathway analysis.

Results
In the hH-Tx rats, many genes in the amyloidal processing pathway showed altered expression, including Akt3 and p38 MAPK. These latter genes are involved in tau protein phosphorylation, and their increased expression in hydrocephalus was confirmed by real-time polymerase chain reaction analysis. Immunohistological and immunoblot analysis revealed elevated phosphorylated tau expression in the cerebral cortex neurons of the hH-Tx rats.

Conclusions
The accumulation of phosphorylated tau protein in the cerebral cortex may be one of the mechanisms by which later cognitive dysfunction develops in patients with compensated hydrocephalus. More work needs to be done to determine if the accumulation of phosphorylated tau in the cortex can help predict which patients may decompensate thus requiring more aggressive treatment for compensated hydrocephalus.
Multiple horizons and information in USDA production forecasts
Authors: Sanders Dwight R. , Manfredo Mark R. 
Published: January 2008

AbstractUnited States Department of Agriculture (USDA) livestock production forecasts are evaluated for their information content across multiple forecast horizons using the direct test developed by Vuchelen and Gutierrez (2005). Forecasts are explicitly tested for rationality (unbiased and efficient) as well as for incremental information out to three‐quarters ahead. The results suggest that although the forecasts are often not rational, they typically do provide the forecast user with unique information at each horizon. Turkey and milk production forecasts are found to provide the most consistent performance, while beef production forecasts provide little information beyond the two‐quarter horizon. [C53, Q13] © 2008 Wiley Periodicals, Inc.
Evaluating animal welfare with choice experiments: an application to Swedish pig production
Authors: Liljenstolpe Carolina 
Published: January 2008

AbstractIn this study, the demand for animal welfare attributes when buying pork fillet is investigated among Swedish respondents. The issue is of importance in order to ensure an economically viable pig industry while applying an increasing number of animal friendly practices. In order to obtain information about consumer demand, an indirect utility function and willingness to pay (WTP) for animal welfare attributes are estimated. The attributes are solely associated with animal friendly practices. An investigation of numerous housing and managerial practices of pig production has not yet been performed. The indirect utility function is estimated using a random parameter logit model. A realistic approach when modeling consumer choice is to allow for heterogeneity in preferences. The relevance of assuming randomness of some of the parameters is evaluated by using a specification test developed by McFadden and Train (2000). The WTP is also estimated at the individual level. The results indicate that WTP for animal welfare attributes may be negative or positive. The preferences are also heterogeneous among respondents, which may be explained by a segmentation of preferences. Finally, the WTP estimates for animal welfare practices are compared with cost estimates for such production systems. [Econlit subject codes: C010, C500, Q100] © 2008 Wiley Periodicals, Inc.
CC Coupling Reactions of Superstrong CF3 Groups with C(sp2)–H Bonds: Reactivity and Synthetic Utility of Zero‐Valent Niobium Catalyst
Authors: Fuchibe Kohei , Mitomi Ken , Suzuki Ryo , Akiyama Takahiko 
Published: January 2008

AbstractIt was found that zero‐valent niobium is an efficient catalyst for the intramolecular CC coupling reactions of o‐aryl and o‐alkenyl α,α,α‐trifluorotoluene derivatives. The superstrong CF bonds of CF3 groups and neighboring C(sp2)H bonds were doubly activated, and fluorenes and indenes were obtained in good yields. The niobium fluorocarbenoid species is proposed to be the key intermediate.
Chemiluminescence of 4‐styrylphthal‐hydrazides with crown ether as ionophore
Authors: Motoyoshiya Jiro , Hotta Masanori , Nishii Yoshinori , Aoyama Hiromu 
Published: January 2008

AbstractTwo 4‐styrylphthalhydrazides bearing crown ether moieties as ionophores were prepared and their chemiluminescence (CL) behaviour was investigated. Their aerobic oxidation in the presence of excess tert‐BuOK in DMSO provided the CL with much shorter emission wavelengths than those of the corresponding phthalate dianions, indicating that the emission arose from the excited phthalates incorporated with potassium ions at the ionophore sites. Such incorporation of potassium ions with the crown sites also reduced the fluorescence intensities of the phthalate dianions which caused an energy transfer CL, resulting in the additional emissions of the phthalhydrazide monoanions in much longer wavelength regions. On the other hand, only the emission from the excited phthalate dianion was detected under aqueous conditions using aqueous hydrogen peroxide in acetonitrile as the oxidant, but no meaningful difference in the CL intensity depending on the kind of metal cations was observed. Copyright © 2008 John Wiley & Sons, Ltd.
Photochemical Generation and Structure of Vinyl Radicals (Eur. J. Org. Chem. 3/2008)
Authors: Goumans Theodorus P. M. , van Alem Kaj , Lodder Gerrit 
Published: January 2008

AbstractThe cover picture shows how the structure of an α‐CN vinyl radical is elucidated through the photolysis of stereoisomeric vinyl halide precursors. The vinyl radical intermediates react with the solvent to form stereoisomeric styrenes. Analysis of the yields of the styrenes as a function of temperature establishes the α‐CN vinyl radical as a rapidly inverting bent, and not linear, species. The photolyses of α‐Me, α‐C(H)=O and α‐F substituted bromostyrenes indicate that the α‐Me vinyl radical is also rapidly inverting, while the α‐C(H)=O and α‐F vinyl radicals are stable bent species. The experimental results are supported by quantum chemical computations. Details are discussed in the article by T. P. M. Goumans et al. on p. 435 ff. Patty Nieuwenburg is acknowledged for the background photo of the dunes of Harlech, Wales.
An investigation of the effect of immediate and extended release venlafaxine on nocturnal melatonin and cortisol release in healthy adult volunteers
Authors: Hallam Karen T. , Begg Denovan P. , Olver James S. , Norman Trevor R. 
Published: January 2008

AbstractThe secretion of the hormone melatonin is particularly robust to the effect of pharmacological agents. Medications may alter melatonin levels through either altering adrenergic activity or affecting liver enzymes involved in melatonin metabolism. The aim of this study was to investigate the effect of venlafaxine, a third generation antidepressant with known adrenergic properties on melatonin secretion. A further aim of the study was to investigate the correlation between plasma and salivary measures on this medication. Eight healthy adult participants (four males, four females) took part in this double blind placebo controlled randomised trial. Participants were tested on 3 nights after taking venlafaxine XR (75 mg), venlafaxine IR (75 mg) or placebo. Participants were placed in a darkened room between 1900 and 0300 h and regular temperature readings, blood and saliva samples were drawn to assess melatonin and cortisol secretion in each condition. There was no significant effect of venlafaxine IR or XR on melatonin concentrations in plasma or saliva and no effects on other circadian parameters including cortisol and temperature. It was notable that the correlation between plasma and salivary melatonin levels became poor after drug treatment. These results indicate that at low doses the mixed serotonergic and noradrenergic drug venlafaxine has no effect on nocturnal melatonin concentrations. Copyright © 2008 John Wiley & Sons, Ltd.