bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Examination of Plasma Membrane–Associated Photosensitizers Using Total Internal Reflection Fluorescence Spectroscopy: Correlation between Photobleaching and Photodynamic Efficacy of Protoporphyrin IX
Authors: Strauss W. S. L. , Sailer R. , Gschwend M. H. , Emmert H. , Steiner R. , Schneckenburger H. 
Published: January 2008

ABSTRACTFluorescence spectra, fluorescence decay kinetics, photobleaching kinetics and photodynamic efficacy of protoporphyrin IX (PP) were investigated in endothelial cells in vitro after different incubation times. Fluorescence spectra and photobleaching kinetics were determined during total internal reflection (TIR) illumination or epiillumination. Because penetration depth of the excitation light during TIR illumination was limited to about 100 nm, plasma membrane‐associated PP was almost selectively examined. Spectra obtained by TIR fluorescence spectroscopy (FS) showed a very low background, where‐as spectra obtained by epi‐illumination exhibited considerable background by autofluorescence and scattered light. For photobleaching kinetics during TIR illumination after 1 h or 24 h incubation, a biexponential fluorescence decrease was observed with a rapidly and a slowly bleaching portion. After 1 h incubation, the rapidly bleaching portion was the predominant fraction, whereas after 24 h incubation comparable relative amounts of the rapidly and slowly bleaching portion were determined. The rapidly and slowly bleaching portion were assigned to PP monomers and aggregated species in close vicinity to the plasma membrane. Fluorescence decay measurements after epi‐illumination support the decrease of PP monomers within the whole cell with increasing incubation time. In contrast to TIR illumination, photobleaching of PP during epi‐illumination was characterized by slow monoexponential fluorescence decrease after 1 h or 24 h incubation. Photodynamic efficacy of PP using epi‐illumination was found to depend strongly on incubation time. Considerable cell inactivation was determined for short incubation times (1 h or 3 h), whereas photodynamic efficacy was diminished for longer incubation times. Reduced photodynamic efficacy after long incubation times was assigned to the lower amount of photodynamically active monomers determined close to the plasma membrane as well as within the whole cell. In conclusion, TIRFS measurements are suggested to be an appropriate tool for the examination of the plasma membrane‐associated photosensitizer fraction in living cells.
Light Regulation of Phytochrome Content in Wild‐type and Aphototropic Mutants of the Moss Ceratodon purpureus
Authors: Esch Heike , Lamparter Tilman 
Published: January 2008

ABSTRACTIn filaments of the moss Ceratodon purpureus, phototropism is controlled by the photoreceptor phytochrome. Thirty‐three aphototropic mutants with a proposed defect in phytochrome‐chromophore biosynthesis were isolated and analyzed. The phototropic response of those mutants was rescued with the precursor of the phytochrome chromophore, biliverdin. Phytochrome spectral activity was measured in 19 arbitrarily chosen mutants. All contained low but still measurable quantities of photoactive phytochrome; the highest level was around 15% of the wild‐type. The level of total phytochrome (apophytochrome and holophytochrome) as assayed by immunoblotting was indistinguishable from wild‐type. The content of photoactive phytochrome in Ceratodon is light‐regulated. Phytochrome of wild‐type kept for 24 h in red light was reduced to 50% as compared to dark controls but was unaffected by blue. The red‐light‐induced decrease was partially reversible by far‐red light, indicating that phytochrome itself is the photoreceptor for this response. This regulation was further analyzed with the mutant ptr114, which contains 15% photoactive phytochrome as compared to the wild‐type. In this mutant, continuous red light given for 6 days decreased the level of spectrally active phytochrome down to 25% of dark controls, whereas the amount of phytochrome found on immunoblots was hardly reduced. This indicates that the loss of phytochrome affects only the holoprotein and implies that Ceratodon phytochrome is specifically degraded as a far‐red‐absorbing phytochrome.
Novel Visible and Ultraviolet Light Photogeneration of Hydroxyl Radicals by 2‐Methyl‐4‐nitro‐quinoline‐N‐oxide (MNO) and 4, 4′‐Dinitro‐(2, 2′) bipyridinyl‐N, N′‐dioxide (DBD)
Authors: Botchway Stanley W. , Chakrabarti Subrata , Makrigiorgos G. Mike 
Published: January 2008

ABSTRACTChemicals that upon absorption of light generate hydroxyl radicals (·OH), free of other damaging species under physiological conditions, are useful tools for the study of the biological effects of ·OH radical and for its utilization for analytical purposes. We report the novel property of 2‐methyl‐4‐nitro‐quinoline‐N‐oxide (MNO) and 4, 4′‐dinitro‐(2, 2′) bipyridinyl‐N, N′‐dioxide (DBD) to act as photogenerators of ·OH with UV and visible light. Upon irradiation with 360–400 nm light MNO and DBD generate free radicals that convert coumarin carboxylic acid (CCA) to fluorescent 7‐OH‐CCA; the ·OH radical scavengers dimethylsulfoxide (DMSO) and ethanol eliminate the induction of 7‐OH‐CCA fluorescence. Upon 400 nm illumination in the presence of MNO, supercoiled plasmid DNA is converted to circular and strand break‐age is significantly reduced in the presence of DMSO and completely absent in the absence of MNO. The conversion of CCA to 7‐OH‐CCA and of supercoiled plasmid to circular DNA are also observed in the absence of oxygen. Taken together, these data indicate that MNO and DBD constitute novel ·OH‐generating compounds. Because currently known ·OH‐photogenerating compounds require UV illumination (< 360 nm) that also damages DNA and cells directly, the property of MNO to generate ·OH upon 400 nm illumination is advantageous when studies on cells, DNA and other biomolecules are conducted.
Inhibitory Effects of Plant Tannins on Ultraviolet Light‐Induced Epidermal DNA Synthesis in Hairless Mice
Authors: Gali‐Muhtasib Hala U. , Perchellet Jean‐Pierre , Khatib Samar H. 
Published: January 2008

ABSTRACTNaturally occurring hydrolyzable (HT) and condensed (CT) tannins and their monomeric units were tested for their ability to inhibit the stimulation of DNA synthesis by UVB radiation. Hairless mice were irradiated with either single (200 mJ/cm2) or multiple (150 mJ/cm2) doses of UVB applied at 24 h intervals and epidermal DNA synthesis was measured at different times after the last of these treatments. The peak of DNA synthesis that is observed 48–56 h after a single UVB irradiation shifts to an earlier time of 16–24 h after multiple UVB treatments. Interestingly, the early inhibitory period of DNA synthesis observed 8 h after a single UVB treatment is not detected following multiple UVB treatments. Rather, DNA synthesis is stimulated six‐fold 24 h after multiple UVB treatment, a response that is higher than the peak occurring 48–56 h after a single UVB irradiation. The disappearance of the early period of inhibition when the peak of DNA synthesis shifts to an earlier time may be linked to reactive oxygen species brought to the epidermis by infiltrating leukocytes, which, in turn, act as second messengers to stimulate growth signals in cells. Topical applications of HT or CT remarkably inhibit the DNA responses to single and multiple UVB treatments, an effect that is dependent on the dose and time of administration. Indeed, the peak stimulation of DNA synthesis is maximally inhibited when 17 mg of Tarapod tannic acid (TA), an HT, are applied topically 20 min before a single UVB treatment. The polymeric tannins inhibited DNA synthesis to a greater degree than equal doses of their monomeric units, gallic acid and catechin. These results suggest that various oligomeric HT and CT may be useful against tumor‐promoting responses associated with the exposure of skin to physical carcinogens.
Fluorescence Properties of Recombinant Tropomyosin Containing Tryptophan, 5‐Hydroxytryptophan and 7‐Azatryptophan
Authors: Das Kaustuv , Ashby Kyle D. , Smirnov Alex V. , Reinach Fernando C. , Petrich Jacob W. , Farah Chuck S. 
Published: January 2008

AbstractTropomyosin mutants containing either tryptophan (122W), 5‐hydroxytryptophan (50H122W) or 7‐azatryp‐tophan (7N122W) have been expressed in Escherichia coli and their fluorescence properties studied. The fluorescent amino acids were located at position 122 of the tropomyosin primary sequence, corresponding to a solvent‐exposed position c of the coiled‐coil heptapeptide repeat. The emission spectrum of the probe in each mutant is blue‐shifted slightly with respect to that of the probe in water. The fluorescence anisotropy decays are single exponential, with a time constant of 2–3 ns while the fluorescence lifetimes of the probes incorporated into the proteins, in water, are nonexponential. Because tryptophan in water has an intrinsic nonexponential fluorescence decay, it is not surprising that the fluorescence decay of 122W is well described by a triple exponential. The fluorescence decays in water of the nonnatural amino acids 5‐hydroxytryptophan and 7‐azatryptophan (when emission is collected from the entire band) are single exponential. Incorporation into tropomyosin induces triple‐exponential fluorescence decay in 5‐hydroxytryptophan and double‐exponential fluorescence decay in 7‐azatryptophan. The range of lifetimes observed for 5‐hy‐droxyindole and 5‐hydroxytryptophan at high pH and in the nonaqueous solvents were used as a base with which to interpret the lifetimes observed for the 50H122W and indicate that the chromophore exists in several solvent environments in both its protonated and unprotonated forms in 50H122W.
Direct Spectroscopic Evidence for 1ΔgO2 Production from the Photolysis of Vanadium(V)‐Peroxo Complexes in Aqueous Solution
Authors: Chou Pi‐Tai , Lee Ming‐Zen , Wel Chin‐Yen , Wu Guo‐Ray , Shek Lai Kuen , Kwong Daniel W. J. 
Published: January 2008

AbstractThe chemiluminescence of 1DLgO2 expelled from the UV photolysis of vanadium(V)‐peroxo (VP) complexes in aqueous solution was observed for the first time. Using phenalenone photosensitization as a standard reference, the 1O2 quantum yields from the photolysis of 12 VP complexes were measured. No good correlation was found between the relative DNA‐photocleavage activities and the 1O2 quantum yields of these complexes. This lack of correlation underscores the significant contribution of the complex‐DNA binding interaction in determining the observed DNA‐photocleavage activity of the complex. The small 1O2 quantum yields observed in these complexes were interpreted in terms of the minor 1O2 pho‐toelimination channel relative to other more efficient relaxation processes.
Partial Protection Against Epidermal IL‐10 Transcription and Langerhans Cell Depletion by Sunscreens after Exposure of Human Skin to UVB
Authors: Hochberg Malka , Enk Claes D. 
Published: January 2008

AbstractSunscreens capable of inhibiting erythema are assumed to protect against UV‐induced carcinogenesis as well. However, the correlation between inflammation and carcinogenesis is uncertain, and the prevention of UV‐induced erythema might in fact be biologically irrelevant as an indicator of protection against UV‐induced skin cancer. Ultraviolet‐B radiation promotes cutaneous immunosuppression by the release of immunoregulatory cytokines and by depletion of Langerhans cells. We investigated the ability of two different sunscreens to inhibit UVB‐induced expression of epidermal interleukin (IL)‐10 and depletion of Langerhans cells. Chemical and physical sunscreens were applied to the forearms of volunteers 15 min prior to 4 minimal erythemal doses of UVB exposure. Suction blisters were induced 24 h after irradiation, and RNA was extracted from the blister roofs. Reverse transcription polymerase chain reaction was performed using primers for IL‐10 and CDla. A chemical sunscreen containing octyl methoxycinnamate (12 sun protection factor [SPF]) and a physical sunscreen containing zinc oxide (16 SPF) were assayed: UVB‐induced IL‐10 mRNA expression was nearly totally inhibited by both sunscreens (median protection for chemical and physical sunscreens was 95% and 78%, respectively), whereas UVB‐induced Langerhans cell depletion was partially prevented (47% and 50% for chemical and physical sunscreens, respectively). Langerhans cell protection by sunscreens was confirmed by estimation of cell density after ATPase staining. In contrast, both sunscreens effectively prevented the induction of UVB‐induced erythema. We believe this to be the first demonstration that sunscreens can prevent the induction of cutaneous mediators of immunosuppression, and that the results indicate that the immunoprotection offered by the sunscreens is significantly lower than their ability to prevent erythema.
A Laser Flash Photolysis Study on Fenofibric Acid
Authors: Boscá Francisco , Miranda Miguel A. 
Published: January 2008

AbstractFenofibric acid (FA) is a photosensitizing drug used in the treatment of hyperlipidemia. This compound follows two different photodegradation pathways: the free acid exhibits the typical benzophenone photoreactivity, while its sodium salt undergoes photodecarboxylation via a triplet biradical, that undergoes intramolecular electron transfer to form a carbanion, or cyclization to give an intramolecular light‐absorbing transient (LAT). The obtained photoproducts are explained as the result of pro‐tonation of the carbanion, ring opening of the LAT with rearrangement or oxygen trapping of any of the triplet intermediates. The above mechanism is supported by direct detection of the triplet state of FA and two long‐lived intermediates in laser flash photolysis experiments. The triplet lifetime of the carboxylate form in methanol is 0.06 μ.s; by contrast, in the case of the free acid, it is 10 times longer. The benzophenone moiety is clearly the key chromophore involved in the photobehavior of FA.
Photochemistry and Photophysics of Papaverine N‐Oxide
Authors: Souto‐Bachiller F. A. , Perez‐lnestrosa E. , Suau R. , Rico‐Gómez R. , Rodríguez‐Rodríguez L. A. , Coronado‐Pérez M. E. 
Published: January 2008

AbstractThe photochemistry and photophysics of papaverine N‐oxide in polar aprotic and protic solvents has been studied in detail. Complex energy and charge‐transfer phenomena between chromophores occur in papaverine. New photochemistry for the papaverine N‐oxide system is reported. Irradiation in protic media results in the formation of an emissive charge‐transfer state with ensuing intramolecular hydroxylation in high isolated yields (75–80%).
SEASONAL AND GENDER DIFFERENCES IN THE PREVALENCE OF INFANT ANEMIA
Authors: Yalcin S. Songül , Dut Raziye , Yurdakok Kadriye , Ozmert Elif 
Published: January 2008

INTRODUCTION: Anemia is the most prevalent nutritional deficiency in the world.
OBJECTIVE: To estimate the prevalence of anemia among infants receiving routine health care in the Hacettepe University Ihsan Doğramacı Children's Hospital Well Baby Clinic in Ankara, Turkey, we conducted a cross-sectional study by using data from 469 healthy infants who had data available on their hemoglobin values at 6 months of age for the last 3 years.
METHODS: Infants with acute or chronic illness or thalassemia and infants who had taken or were taking iron supplementation at the time were not included in the study. Information regarding the children was obtained from hospital files. Infants with a hemoglobin level of &lt;10.5 and &lt;9.5 g/dL were considered to be mildly and moderately anemic, respectively, at 6 months of age.
RESULTS: The mean level of hemoglobin was 10.7 g/dL (SD: 0.90). The prevalence of anemia was 41.4%. Boys had significantly lower hemoglobin and hematocrit levels and mean corpuscular volume than girls. Infants born before 37 weeks' gestational age had moderate anemia more frequently. Infants born in spring or summer had anemia more frequently than those born in fall or winter (49.2% and 26.8%, respectively; P &lt; .001). Birth weight and monthly weight gain from 6 to 9 months were positively correlated with hemoglobin value at 6 months (r = 0.14, P = .003 and r = 0.10, P = .041, respectively).
CONCLUSIONS: Anemic infants aged 6 months had an increased risk of developing growth failure from 6 to 9 months. In this study, the prevalence of anemia observed was of severe public health significance and justifies the need to emphasize, in prenatal and infant health programs, intervention measures that consider season of birth for anemia control.
EFFECTS OF MESENCHYMAL STEM CELL TRANSPLANTATION ON CARDIAC FUNCTION, STRUCTURE, AND ELECTROPHYSIOLOGY IN RABBITS WITH DILATED CARDIOMYOPATHY
Authors: Jie Tian , Shen Xing , Yu Geng-Sheng , Bai Yong-Hong , Zhu Jing , Liu Guan-Xin , Chen Yuan 
Published: January 2008

OBJECTIVE: The objective of this study was to explore the influence of implanted mesenchymal stem cells (MSCs) on cardiac function, structure, and electrophysiology in rabbits with dilated cardiomyopathy (DCM).
METHODS: Thirty-eight rabbits were randomly assigned to 3 groups: (1) normal rabbits (n = 12); (2) rabbits with DCM cell implantation (n = 13); or (3) DCM control rabbits (n = 13). Adriamycin was applied to create the rabbit DCM model. Rabbits for cell transplantation received an intramyocardial injection of MSCs. Four weeks later, heart function morphology and electrophysiology changes were observed. The expression of cardiac Troponin T and connexin 43 was investigated through immunohistochemistry.
RESULTS: Compared with normal rabbits, the cardiac function of DCM rabbits was impaired, but this impaired function was improved by MSC implantation. The value for monophasic action potential amplitude and the maximum velocity in ¡°0¡±phase decreased significantly in DCM rabbits, whereas the value for 50% monophasic action potential durations (MAPD) and 90% MAPD were increased significantly. The effective refractory period increased also. The comparison of both DCM groups showed that the prolongation of MAPD was shorter in the cell implantation group than in the DCM control group, and no after-depolarization was observed, whereas early after-depolarization was recorded in 2 rabbits in the DCM control group. Histology analysis showed that the structural abnormalities in the cell implantation group were less than those in the DCM control group, and the implanted MSCs could express cardiac Troponin T and connexin 43.
CONCLUSIONS: Implanted MSCs can improve heart function, reduce the structural abnormalities, and possibly inhibit the progression of electrophysiologic derangement.
SHOULD THE PELVIS BE INCLUDED IN ABDOMINAL COMPUTED TOMOGRAPHY SCANS OF CHILDREN WITH UPPER-ABDOMINAL PRIMARY MALIGNANT TUMORS?
Authors: Hadgigeorgi Christiana , Zarifi Maria , Pitsoulakis George , Tavernaraki Ekaterini , Makri Triantafyllia 
Published: January 2008

INTRODUCTION: There is increasing awareness of the potential risk associated with ionizing radiation in pediatric radiology. Children with abdominal cancer undergo multiple computed tomography (CT) scans both at diagnosis and for follow-up.
OBJECTIVE: We sought to estimate the potential contribution of pelvis CT findings in the management of children with upper-abdominal tumors in correlation with the effective radiation dose.
METHODS: Three hundred forty-two children (aged 1 day to 16 years) with histologically proven upper-abdominal primary malignant tumors (children with lymphoma were not included) were examined during the last 15 years in our department. Their upper- and lower-abdominal CT scans were reviewed retrospectively for clinically significant pelvic abnormalities. The effective radiation dose for each abdominal area was calculated.
RESULTS: Nine children (2.63%) showed CT pelvic abnormalities that did not change clinical management, and 7 (2.04%) showed findings that affected tumor staging. Thirty-nine percent of the total effective radiation dose was from pelvic CT scans.
CONCLUSIONS: Our data indicate that clinically significant pelvic CT findings are rare in children with upper-abdominal primary malignant tumors. We suggest that the pelvis should not be routinely included in abdominal CT scans unless indicated by other clinical or laboratory findings, given the high level of effective radiation dose.
BEHAVIORAL PROBLEMS IN CHILDREN WITH LEARNING DIFFICULTIES ACCORDING TO THEIR PARENTS AND TEACHERS
Authors: Diakakis Panagiotis , Gardelis John , Ventouri Kiriaki , Nikolaou Katerina , Koltsida Georgia , Tsitoura Styella , Constantopoulos Andreas 
Published: January 2008

INTRODUCTION: Learning difficulties (LDs) are associated with increased comorbidity, especially depression and anxiety. Studies have shown that 24% to 52% of children with LDs present with behavioral problems (BPs).
OBJECTIVE: The aim of our study was to evaluate whether parents' and teachers' opinions concerning BPs in children with LDs are identical.
METHODS: For this purpose, 658 students (aged 7–10 years) in elementary schools were evaluated by specialized questionnaires for parents and teachers. Of those students, 102 (15.5%) were identified as having LDs according to their teachers. The questions regarded symptoms of depression, anxiety/stress, irritability, and other BPs.
RESULTS: Our findings in children with LDs are summarized in Table 1.
CONCLUSIONS: BPs resulting from reduced self-confidence and anxiety/stress were observed at a higher rate by the teachers than by the parents, who more often acknowledged symptoms of social isolation and aggressive behavior. Stress was the BP about which parents and teachers gave identical replies.
TABLE 1.Behavioral Problems in Children With LDsTeachers and Parents Agree That There Are No BPs, %Teachers and Parents Agree That There Are BPs, %Only the Teachers Consider That There Is a BP, %Only the Parents Consider That There Is a BP, %Reduced self-confidence24.626.342.17.0Complains of headache/bellyache19.428.437.314.9Feeling tired frequently13.624.256.16.1Other children tease him/her42.613.216.227.9Being alone, without friends37.111.335.516.1Being unreliable48.412.510.928.1Often fights with other children48.520.613.217.6Increased irritability36.820.611.830.9
LIPID PROFILE OF PREMATURE INFANTS UP TO THE AGE OF 3 YEARS
Authors: Apostolou Helen , Tsekoura Efi , Bouza Helen , Anatolitou Fani , Tzanetakou Irini , Panousopoulou Christina , Koumenidou Maria , Anagnostakou Marina 
Published: January 2008

INTRODUCTION: Current literature indicates a high incidence of cardiovascular disease in later life of premature infants with low birth weight.
OBJECTIVE: The purpose of this study was to investigate serum lipid levels of prematurely born infants up to the age of 3 years.
METHODS: From 2001 to 2005, 171 premature newborns were studied in the follow-up clinic. Patients were divided into 4 groups according to gestational age (≤30 and &gt;30 weeks) and birth weight (≤1000 and &gt;1000 g). Serum levels of cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein were recorded at 12, 24, and 36 months of life.
RESULTS: Cholesterol levels were within the reference range in every given period, independent of age. Infants with low birth weight (≤1000 g) had significantly increased cholesterol levels compared with those with higher birth weight (&gt;1000 g) (P = .013). All groups had significantly higher serum triglyceride levels (P = .001) during the first year of life in comparison to all other periods. In addition, infants with low birth weight had significantly higher serum triglyceride levels (P = .015) during the second year of life than infants with higher birth weight.
CONCLUSIONS: Premature infants with low birth weight have increased cholesterol and triglyceride levels during the early years of life, which is a finding that might be related to a high incidence of atherogenesis in later life and requires additional investigation.