bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Absorption of Blood Depends on Temperature during a 0.5 ms Laser Pulse at 586 nm
Authors: Verkruysse Wim , Nilsson Annika M. K. , Milner Thomas E. , Beek Johan F. , Lucassen Gerald W. , van Gemert Martin J. C. 
Published: January 2008

ABSTRACTOptical properties are important parameters in port wine stain laser treatment models. In this study we investigated whether changes in blood optical properties occur during a 0.5 ms laser pulse. Blood from three volunteers was irradiated in vitro with laser pulses (radiant exposure 2–12 J cm−2, wavelength 586 nm, pulse length 0.5 ms). Reflection and transmission coefficients, measured using double integrating spheres, decreased slightly during the first part of the pulse. At 2.9 J cm−2 radiant exposure, the reflectance increased, independent of total radiant exposure of the pulse. This was caused by blood coagulation. A second sudden increase in reflection and a significant increase in transmission occurred near 6.3 J cm–2 and was accompanied by a "popping" sound, indicating rapid expansion of bubbles due to blood vaporization. A multilayered model of blood was used to fit calculated transmission coefficient curves to the measurements and determine temperature‐dependent optical blood absorption. Heat diffusion was shown to be of minor importance. A 2.5‐fold increase in absorption for temperatures increasing from 20 to 100°C, accurately describes transmission coefficients measured up to 2.9 J cm−2.
Factors Affecting Virus Photoinactivation by a Series of Phenothiazine Dyes
Authors: Wagner Stephen J. , Skripchenko Andrey , Robinette Daniel , Foley James W. , Cincotta Louis 
Published: January 2008

ABSTRACTA series of four phenothiazine dyes, including methylene blue (MB), were previously tested for their ability to photoinactivate viruses in red cell suspensions. One of the dyes, 1,9‐dimethyl‐3‐dimethylamino‐7‐dimethylaminophenothiazine (1,9‐dimethylmethylene blue), exhibited good intracellular and extracellular virucidal activity for several RNA and DNA viruses under conditions that minimally affected red cell properties. In order to understand why the virucidal specificity of 1, 9‐dhnethylmethylene blue was greater than other phenothiazines tested, the physical and chemical properties of the dye were compared to three other closely related analogues (MB, 1,9‐dimethyl‐3‐diethylamino‐7‐dlbutylaminophenothiazine [compound 4‐140], 1,9‐dimethyl‐3‐dimethylamino‐7‐diethylaminophenothiazine [compound 6‐136]). All compounds required light and oxygen for virucidal activity and had relatively high singlet oxygen yields (>0.5), but 1,9‐dimethylmethylene blue had a singlet oxygen yield approximately 50% greater than that of MB. In addition, the hydrophobicity/hydophilicity of the compounds varied, with the partition coefficients (2‐octanol : water) ranging from 0.11 for MB to 3560 for compound 4‐140. The dyes had the following affinities for DNA: 1,9‐dimethylmethylene blue > compound 6‐136 > MB ∼ compound 4‐140. This order was similar to the order of activities for photoinactivation of the nonenveloped bacteriophage, R17, by the four compounds. Results with the most hydrophobic compound, 4‐140, contrasted with those obtained with 1,9‐dimethylmethylene blue. Compound 4‐140 had a high affinity for protein and a low affinity for DNA. Although compound 4‐140 and light inactivated the nonenveloped bacteriophage R17 poorly, the dye readily photoinactivated enveloped viruses in buffer. However, unlike results with 1,9‐dimethylmethylene blue, viral inactivation of enveloped viruses by compound 4‐140 was completely inhibited by the presence of red cells and plasma. Thus, the high affinity of 1,9‐di‐methyymethylene blue for DNA and the dye's efficient singlet oxygen yield suggest viral nucleic acid as a potential target, which could explain the photosensitizer's ability to inactivate viruses without adversely affecting anuclete red cells.
Fluoroquinolone Antimicrobials: Singlet Oxygen, Superoxide and Phototoxicity
Authors: Martinez Lydia J. , Sik Robert H. , Chignell Colin F. 
Published: January 2008

ABSTRACTThe fluoroquinolone antibacterial agents possess photo‐sensitizing properties that lead to phototoxic responses in both human and animal subjects. The phototoxicity order reported in humans is: fleroxacin > lomefloxacin, pefloxacin > ciprofloxacin ≫ enoxacin, norfloxacin and ofloxacin. Studies both in vivo and in vitro have related this phototoxicity to the generation of reactive oxygen species including hydrogen peroxide and the hydroxyl radical. We determined the quantum yields of singlet oxygen generation (φΔ,) by detection of the singlet oxygen (1O2) luminescence at 1270 tun for several fluoroquinolones, naphthyridines and other structurally related compounds. All the fluoroquinolones examined have low φΔ values ranging from 0.06 to 0.09 in phosphate buffer at pD 7.5. We also determined the 1O2 quenching constants for these compounds and their values were on the order of 106M−1 s1, except for lomefloxacin whose rate constant was 1.8 × 107M−1 s−1. The φΔ values were significantly decreased in a solvent of lower polarity such as methanol (0.007 ≤φΔ≤ 0.02). The production of 1O2 by these antibiotics did not correlate with the order reported for their phototoxicity. We also measured the photogeneration (λ > 300 nm) of superoxide by these antibacterials in dimethylsulfoxide using electron paramagnetic resonance and the spin trap 5,5‐dimethyl‐l‐pyrroiine N‐oxide. Although there is not a one‐to‐one correspondence between the relative rates of superoxide generation and the phototoxicity ranking of the fluoroquinolones, the more phototoxic compounds tended to produce superoxide at a faster rate. Nevertheless, the magnitudes of the observed differences do not appear sufficient to explain the range of fluoroquinolone phototoxicity potencies in human and animal subjects in general and the high activity of fleroxacin and lomefloxacin in particular. For these latter drugs the photoinduced loss of the F8 atom as fluoride and the concomitant generation of a highly reactive carbene at C‐8 provide a more plausible mechanism for their potent phototoxic and photocarcinogenic properties.
The Development of Solid Spectral Filters for the Regulation of Plant Growth
Authors: van Haeringen C. J. , West J. S. , Davis F. J. , Gilbert A. , Hadley P. , Pearson S. , Wheldon A. E. , Henbest R. G. C. 
Published: January 2008

ABSTRACTPhthalocyanine derivatives have been prepared and incorporated into polymer films for use as spectral filters for the modification of plant growth. The unusual absorption characteristics of phthalocyanines, notably the narrow absorption band in the visible region of the electromagnetic spectrum, allows the selective filtering of wavelengths necessary for excitation of either of the two isomeric phytochrome species. The resulting change in the photostationary state for the phytochrome is shown to have a marked effect on the growth characteristics of both chrysanthemums and antirrhinums. Chrysanthemums (short‐day plants) grown under a far‐red‐absorbing film showed a reduction in height (∼14%) and internodal length compared to those grown under a red‐absorbing film or a control with no absorption in the visible part of the spectrum; both leaf number and time to flowering were not affected by the presence of the spectral filter. For antirrhinums (long‐day plants) both a reduction in height and a substantial increase in leaf area (70%) of the plants grown under the far‐red‐absorbing film were observed, although flowering was delayed. The potential of these filters as replacements for chemical plant growth regulators is discussed.
Characterization of Photodegradation of Meta‐tetra (Hydroxyphenyl)chlorin (mTHPC) in Solution: Biological Consequences in Human Tumor Cells
Authors: Belitchenko I. , Melnikova V. , Bezdetnaya L. , Rezzoug H. , Merlin J.L. , Potapenko A. , Guillemin F. 
Published: January 2008

ABSTRACTThe photobleaching of meta‐tetra(hydroxyphenyl)chlorin mTHPC) (irradiation wavelength 413 nm) in protein‐containing solution was evaluated by decay in absorbance in Soret band and in fluorescence (λexc= 423 nm, λem= 655 nm). Light exposure resulted in a decrease in absorption throughout the spectrum and simultaneous appearance of new absorption bands in the spectral region 325–450 nm. The rate of mTHPC photodegradation, followed by decay in absorbance, was 15‐fold lower than that observed in fluorescence. This fact reflects the photobleaching of presumably monomeric, fluorescing species of mTHPC. In order to determine the consequences of photobleaching of fluorescing mTHPC material on cellular uptake and photocytotoxicity, human HT29 colon adenocarcinoma cells were incubated with photobleached mTHPC during 5 h with or without following irradiation with the fixed fluence. Surprisingly, but up to the time when the fluorescence decreased by 50%, only a slight decrease in photocytotoxicity was detected. Either aggregated forms that have been taken up undergo intracellular monomerization (but we did not observe increase in fluorescence in living cells) or the photodynamic activity is mostly due to aggregates. The discrepancy of m‐THPC‐photodynamic therapy (PDT) effect and fluorescence measurements may suggest that aggregated m‐THPC plays an important role in mTHPC‐PDT.
Reactivity of Singlet Oxygen with Tryptophan Residues and with Melittin in Liposome Systems
Authors: Vilensky Anna , Feitelson Jehuda 
Published: January 2008

AbstractThe reactivity of singlet oxygen, 1O2, with amino acids, polypeptides and proteins has been studied extensively in solution, in micelles and also in vesicles. Here we attempt to examine its reactivity with iV‐acetyltryptophan amide (NATA), with a tryptophan residue with a long aliphatic chain attached, Trp(CH2)16, and with melittin–a small membrane protein–in a solution containing liposomes. In such a heterogeneous system the sensitizer and/or the tryptophan residue can be located in the ambient DzO, in the liposome membrane or at the membrane‐solution interface. The sensitizer meso‐tetra(N‐methyl‐4 pyri‐dyDporphine tetratosylate (mTPTT) is located in the aqueous phase while hematoporphyrin (HP) is embedded in the membrane. The quenching of 1O2 by the tryptophan residues and by melittin in solution, when using either of the sensitizers, was compared with the data in the liposome‐containing system. It was found that the location of the sensitizer and of the quencher in the liposome membrane or in the surrounding solution greatly affects the quenching rate constants of 1O2.
Singlet Oxygen Toxicity Is Cell Line‐dependent: A Study of Lipid Peroxidation in Nine Leukemia Cell Lines
Authors: Schafer Freya Q. , Buettner Garry R. 
Published: January 2008

AbstractSinglet oxygen (1O2) can be quenched by water, lipids, proteins, nucleic acids and other small molecules. Polyunsaturated fatty acids (PUFA) of cells principally quench 1O2 by chemical mechanisms, producing lipid hydroperoxides, while proteins physically and chemically quench 1O2. Because cell lines can have different PUFA and protein levels, we hypothesized that 1O2 toxicity will vary between cell lines. We used Photofrin® as a source of 1O2. Exposure of nine different leukemia cell lines (CEM, HEL, HL‐60, K‐562, KG‐1, L1210, Molt‐4, THP‐1 and U‐937) to Photofrin and light results in changes in membrane permeability (trypan blue) that vary with cell line. The greater the lipid content of the cell line, the less susceptible they are to membrane damage. When the cell media was supplemented with docosahexaenoic acid (DHA, 22:6), the overall unsaturation of cellular lipids increased. Photofrin and light resulted in increased radical formation in these supplemented cells compared to controls; however, there was no difference in membrane permeability between DHA‐supplemented and control cells. Lipid‐derived radical formation (electron paramagnetic resonance spin trapping) was cell line dependent; but no correlation between lipid content of cells and radical formation was found. However, we found that the greater the protein content of cells the more they were protected against membrane damage induced by Photofrin photosensitization. This suggests that cellular proteins are a key target for 1O2‐mediated toxicity. A remarkable observation is that cell size correlates inversely with ability of cells to cope with a given flux of 1O2.
Laser Fluence for Permanent Damage of Cutaneous Blood Vessels
Authors: Barton Jennifer Kehlet , Vargas Gracie , Pfefer T. Joshua , Welch Ashley J. 
Published: January 2008

AbstractTreatment of vascular disorders may be improved by a more thorough understanding of laser‐blood vessel interaction. In this study, the probability of permanent damage to a given type and size of blood vessel was determined as a function of fluence at the top (superficial edge) of the vessel lumen. A 532 nm wavelength, 10 ms pulse duration, 3 mm spot size laser was used to perform approximately 250 irradiations of subdermal blood vessels in the hamster dorsal skin flap preparation. The radiant exposure required for a 50% probability of permanent damage was calculated using a probit analysis of experimental results. Threshold radiant exposure increased with larger blood vessel diameters and was greater for arterioles than venules. Monte Carlo modeling of a typical blood vessel geometry revealed that fluence at the top of the blood vessel lumen was amplified by a factor of approximately 2.4 over tissue surface radiant exposure, due to light scattering in the tissue and internal reflection at the skin‐air interfaces.
Cell Density–Dependent Increase of Constitutive Signal Transducers and Activators of Transcription 3 Activity in Melanoma Cells Is Mediated by Janus Kinases
Authors: Kreis Stephanie , Munz Georg A. , Haan Serge , Heinrich Peter C. , Behrmann Iris 
Published: January 2008

AbstractSignal transducers and activators of transcriptions (STAT) are key mediators of cytokine signaling. Moreover, these transcription factors play a crucial role in oncogenic signaling where inappropriate and sustained activation of STATs, especially STAT3, is a trait of many different cancers and their derived cell lines. Constitutively active STAT3 has been reported to prevent programmed cell death and enhance cell proliferation, whereas the disruption of STAT3 signaling can inhibit tumor growth. The physiologic activation of STAT3 by cytokines has been well established; however, little is known about altered, stimulation-independent STAT3 activation. Here, we show that, in most but not all melanoma cell lines, STAT3 phosphorylation increased substantially with cell density and that this STAT3 was able to bind to DNA and to activate transcription. Inhibitor studies showed that the cell density–dependent STAT3 activation relies on Janus kinases (JAK) rather than Src kinases. Using a specific JAK inhibitor, sustained STAT3 activation was completely abrogated in all tested melanoma lines, whereas inhibition of Src or mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 had no effect on constitutively tyrosine-phosphorylated STAT3 levels. Although STAT3 activation was completely blocked with JAK inhibitor I and to a lesser extent with the common JAK inhibitor AG490, only the latter compound markedly decreased proliferation and induced apoptosis. Taken together, variations in cell density can profoundly modify the extent of JAK-mediated persistent STAT3 phosphorylation; however, STAT3 activation was not sufficient to provide critical growth and survival signals in melanoma cell lines. (Mol Cancer Res 2007;5(12):1331–41)
A simple principle concerning the robustness of protein complex activity to changes in gene expression
Authors: Semple Jennifer I , Vavouri Tanya , Lehner Ben 
Published: January 2008

Abstract

Background
The functions of a eukaryotic cell are largely performed by multi-subunit protein complexes that act as molecular machines or information processing modules in cellular networks. An important problem in systems biology is to understand how, in general, these molecular machines respond to perturbations.

Results
In yeast, genes that inhibit growth when their expression is reduced are strongly enriched amongst the subunits of multi-subunit protein complexes. This applies to both the core and peripheral subunits of protein complexes, and the subunits of each complex normally have the same loss-of-function phenotypes. In contrast, genes that inhibit growth when their expression is increased are not enriched amongst the core or peripheral subunits of protein complexes, and the behaviour of one subunit of a complex is not predictive for the other subunits with respect to over-expression phenotypes.

Conclusion
We propose the principle that the overall activity of a protein complex is in general robust to an increase, but not to a decrease in the expression of its subunits. This means that whereas phenotypes resulting from a decrease in gene expression can be predicted because they cluster on networks of protein complexes, over-expression phenotypes cannot be predicted in this way. We discuss the implications of these findings for understanding how cells are regulated, how they evolve, and how genetic perturbations connect to disease in humans.
MetaReg: a platform for modeling, analysis and visualization of biological systems using large-scale experimental data
Authors: Ulitsky Igor , Gat-Viks Irit , Shamir Ron 
Published: January 2008

AbstractMetaReg http://acgt.cs.tau.ac.il/metareg/application.html is a computational tool that models cellular networks and integrates experimental results with such models. MetaReg represents established knowledge about a biological system, available today mostly in informal form in the literature, as probabilistic network models with underlying combinatorial regulatory logic. MetaReg enables contrasting predictions with measurements, model improvements and studying what-if scenarios. By summarizing prior knowledge and providing visual and computational aids, it helps the expert explore and understand her system better.
LAPAROSCOPIC CHOLECYSTECTOMY IN CHILDREN: A 5-YEAR EXPERIENCE
Authors: Papandreou Evangelos , Gentimi Fotini , Baltogiannis Nikolaos , Livaditi Evangelia , Loukas Ierotheos , Christopoulos-Geroulanos Georgios 
Published: January 2008

INTRODUCTION: Cholecystectomy in children is not a common surgical procedure. In the past 5 years, we have performed it laparoscopically. There was no difference in insufflated pressure between 2 groups while no drainage catheter was placed.
OBJECTIVE: We present a modified laparoscopic technique in children.
METHODS: In a 5-year period, 54 children underwent laparoscopic cholecystectomy. Their ages ranged from 14 months to 15 years (mean: 7.6 years). Depending on the applied technique, the patients were separated into 2 groups. The first group comprised 17 patients on whom we performed the conventional 4-port technique. The second group comprised 37 patients on whom a modified technique was performed. We used 3 ports: an umbilical port for the camera, another in the subxifoid region for the dissector, and a third in the right lower quadrant for the grasping clamp and the extraction of the gallbladder. Vessel sealing electrocautery was used for ligation of the cystic artery and detachment of the gallbladder.
RESULTS: Reduction of the number of ports had no effect on accessibility and duration of the procedure; however, it simplified access and handling, particularly in the smaller patients. Conversion to open cholecystectomy was performed in 1 case with major deformities of the vertebral column. The duration of hospitalization varied from 1 to 4 days (mean: 2.7 days).
CONCLUSIONS: The decreased number of ports and the use of vessel sealing electrocautery make laparoscopic cholecystectomy in children easier and safe, without affecting the perioperative time.
Hemorrhagic and nonhemorrhagic Rathke cleft cysts mimicking pituitary apoplexy
Authors: Binning Mandy J. , Liu James K. , Gannon John , Osborn Anne G. , Couldwell William T. 
Published: January 2008

Object
Rathke cleft cysts (RCCs) are infrequently symptomatic, and apoplexy is one of the most unusual presentations. Only a few cases of apoplexy associated with RCCs have been reported, and their clinical, imaging, surgical, and pathological features are poorly understood. In the cases that have been reported, intracystic hemorrhage has been a consistent finding. The authors report 6 cases of RCCs in which the presenting clinical and imaging features indicated pituitary apoplexy, both with and without intracystic hemorrhage.

Methods
The authors retrospectively reviewed charts and magnetic resonance (MR) imaging studies obtained in patients who underwent transsphenoidal surgery for RCC. Six patients were identified who presented with symptoms and MR imaging characteristics consistent with pituitary apoplexy but were found intraoperatively to have an RCC. All 6 patients presented with a sudden headache, 2 with visual loss, and 1 with diplopia. Review of the preoperative MR images demonstrated mixed signal intensities in the sellar masses suggestive of a hemorrhagic pituitary tumor. In all patients there was a presumed clinical diagnosis of pituitary tumor apoplexy and an imaging-documented diagnosis of hemorrhagic pituitary tumor.

Results
All 6 patients underwent transsphenoidal resection to treat the suspected pituitary apoplexy. Intraoperative and histopathological findings were consistent with the diagnosis of an RCC in all cases. Only 2 cases showed evidence of hemorrhage intraoperatively. In all cases, an intracystic nodule was found within the RCC at surgery, and this intracystic nodule was present on the initial MR imaging when retrospectively reviewed. The imaging characteristics of the intracystic nodules were similar to those of acute hemorrhage seen in cases of pituitary apoplexy.

Conclusions
The clinical and imaging features of RCCs appear similar to those of hemorrhagic pituitary tumors, making them often indistinguishable from pituitary apoplexy.
Preoperative depiction of cavernous sinus invasion by pituitary macroadenoma using three-dimensional anisotropy contrast periodically rotated overlapping parallel lines with enhanced reconstruction imaging on a 3-tesla system
Authors: Yoneoka Yuichiro , Watanabe Naoto , Matsuzawa Hitoshi , Tsumanuma Itaru , Ueki Satoshi , Nakada Tsutomu , Fujii Yukihiko 
Published: January 2008

Object
Three-dimensional anisotropy contrast (3DAC) magnetic resonance (MR) imaging provides clear depiction of neuronal fibers. The aim of this study was to identify intracavernous cranial nerves in patients with pituitary macro-adenoma and in healthy volunteers by using 3DAC MR imaging on a 3-tesla system and to preoperatively predict cavernous sinus invasion by pituitary macroadenoma.

Methods
Thirty-three patients (cavernous sinuses in 66 sides) with pituitary macroadenomas and 25 healthy volunteers (50 sides) participated in this study. Coronal 3DAC MR images constructed from diffusion weighted images, acquired with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) sequences, and T2-weighted reverse images were obtained at the same anatomical locations using a 3-tesla MR imaging system. Attempts were made to identify the cranial nerves.

Results
The oculomotor and ophthalmic/maxillary nerves were preoperatively identified in all sides (66 sides in patients and 50 sides in healthy volunteers) on 3DAC MR images. In the 33 patients, cavernous sinus invasion was revealed in 10 (12 [18.2%] of 66 sides) by intraoperative endoscopic observation. Coronal 3DAC MR images revealed that the oculomotor nerves were half surrounded with adenoma in all 12 of these sides, and the ophthalmic/maxillary nerves were half encapsulated with tumor (sensitivity/specificity: 100%/100% and 83%/100%, respectively).

Conclusions
Preoperative evaluation of pituitary macroadenomas using 3DAC PROPELLER MR imaging on a 3-tesla system is likely to be a powerful noninvasive method of detecting cavernous sinus invasion, which can potentially dominate the therapeutic strategy for these lesions.