Inactivation of Tissue Thromboplastin by Ultraviolet Irradiation

1968 ◽  
Vol 19 (01/02) ◽  
pp. 221-225
Author(s):  
S Åtland ◽  
M Hvatum ◽  
H Prydz
Keyword(s):  
Absorption Spectrum ◽  
Exponential Function ◽  
Ultraviolet Irradiation ◽  
Uv Light ◽  
Action Spectrum ◽  
Radiation Energy ◽  
Procoagulant Activity ◽  
Tissue Thromboplastin ◽  
Protein Part ◽  
Uv Absorption Spectrum

SummarySolutions of partially purified tissue thromboplastin have been irradiated with UV light of different wavelengths, and the resulting reduction in the procoagulant activity has been measured. The activity decreased as an exponential function of the dose. The action spectrum obtained was closely similar to the UV absorption spectrum of the thromboplastic preparations and had a maximum between 270-290 nm. The data suggested that the reduction in the procoagulant activity was caused by absorption of radiation energy in the protein part of the thromboplastic structure.

scholarly journals Modification of Cyclic Nucleotide–Gated Ion Channels by Ultraviolet Light

2000 ◽  
Vol 116 (2) ◽  
pp. 227-252 ◽  
Author(s):  
Thomas R. Middendorf ◽  
Richard W. Aldrich ◽  
Denis A. Baylor
Keyword(s):  
Absorption Spectrum ◽  
Ion Channels ◽  
Ultraviolet Light ◽  
Cyclic Nucleotide ◽  
Uv Light ◽  
Action Spectrum ◽  
Light Sensitivity ◽  
Current Reduction ◽  
Photochemical Modification ◽  
Gated Ion Channels

We irradiated cyclic nucleotide–gated ion channels in situ with ultraviolet light to probe the role of aromatic residues in ion channel function. UV light reduced the current through excised membrane patches from Xenopus oocytes expressing the α subunit of bovine retinal cyclic nucleotide–gated channels irreversibly, a result consistent with permanent covalent modification of channel amino acids by UV light. The magnitude of the current reduction depended only on the total photon dose delivered to the patches, and not on the intensity of the exciting light, indicating that the functionally important photochemical modification(s) occurred from an excited state reached by a one-photon absorption process. The wavelength dependence of the channels' UV light sensitivity (the action spectrum) was quantitatively consistent with the absorption spectrum of tryptophan, with a small component at long wavelengths, possibly due to cystine absorption. This spectral analysis suggests that UV light reduced the currents at most wavelengths studied by modifying one or more “target” tryptophans in the channels. Comparison of the channels' action spectrum to the absorption spectrum of tryptophan in various solvents suggests that the UV light targets are in a water-like chemical environment. Experiments on mutant channels indicated that the UV light sensitivity of wild-type channels was not conferred exclusively by any one of the 10 tryptophan residues in a subunit. The similarity in the dose dependences of channel current reduction and tryptophan photolysis in solution suggests that photochemical modification of a small number of tryptophan targets in the channels is sufficient to decrease the currents.

Directed exospermia: I. Biological modes of resistance to UV light are implied through absorption spectroscopy of DNA and potential UV screens

2007 ◽  
Vol 6 (3) ◽  
pp. 229-240 ◽  
Author(s):  
Andreja Zalar ◽  
David Tepfer ◽  
Søren V. Hoffmann ◽  
John M. Kenney ◽  
Sydney Leach
Keyword(s):  
Amino Acids ◽  
Absorption Spectrum ◽  
Uv Light ◽  
Life Forms ◽  
Uv Absorption ◽  
Dna Protection ◽  
Current Role ◽  
Terrestrial Life ◽  
Selection Of ◽  
Uv Absorption Spectrum

AbstractPanspermia, the dissemination of life through space, would require resistance to the conditions found in space, including UV light. All known life forms depend on DNA to store information. In an effort to understand the liabilities of DNA to UV light and modes of DNA protection in terrestrial life forms, we established UV–VUV (125–340 nm) absorption spectra for dry DNA and its polymerized components and mononucleotides, as well as for a selection of potential UV screens ubiquitous in all organisms, including proteins, selected amino acids and amines (polyamines and tyramine). Montmorillonite clay was included as a potential abiotic UV screen. Among the potential screens tested, adenosine triphosphate (ATP) appeared to be particularly attractive, because its UV absorption spectrum was similar to that of DNA. We suggest that the use of ATP in UV protection could have pre-dated its current role in energy transfer. Spectroscopy also showed that UV absorption varied according to nucleotide content, suggesting that base pair usage could be a factor in adaptation to given UV environments and the availability of UV screens.

scholarly journals Bacteriorhodopsin induces a light-scattering change in Halobacterium halobium.

1978 ◽  
Vol 79 (3) ◽  
pp. 657-662 ◽  
Author(s):  
C L Wey ◽  
P L Ahl ◽  
R A Cone
Keyword(s):  
Absorption Spectrum ◽  
Light Scattering ◽  
Near Infrared ◽  
Action Spectrum ◽  
Bright Light ◽  
Infrared Region ◽  
Halobacterium Halobium ◽  
Scattering Response ◽  
Near Infrared Region ◽  
Hypertonic Shock

When suspensions of Halobacterium halobium are exposed to bright light, the light-scattering properties of the bacteria change. This light-scattering response can produce a transmission decrease of about 1% throughout the red and near-infrared region. The action spectrum for the light-scattering response appropriately matches the absorption spectrum of bacteriorhodopsin. The response is eliminated by cyanide p-trifluoro-methoxyphenylhydrazone, a proton ionophore, and by triphenylmethylphosphonium, a membrane permanent cation. A mild hypertonic shock induces a similar light-scattering change, suggesting that bright light causes the bacteria to shrink about 1% in volume, thereby producing the light-scattering response.

scholarly journals Comparative study of oxytetracycline and doxycycline on calcium chelation: in-vitro assay

2017 ◽  
Vol 6 (5) ◽  
pp. 1160 ◽  
Author(s):  
Savitri Katlam ◽  
Yeshwant A. Deshmukh ◽  
Pradeep R. Jadhav
Keyword(s):  
Absorption Spectrum ◽  
Calcium Binding ◽  
Binding Assay ◽  
Pharmacokinetic Profile ◽  
In Vitro Assay ◽  
Vitro Assay ◽  
Calcium Chelation ◽  
Different Doses ◽  
Uv Absorption Spectrum

Background: Tetracycline class of antibiotics differ in their pharmacokinetic profile and chelating property. Objective of present study is to assess the effect of oxytetracycline and doxycycline on calcium chelationMethods: For estimation of calcium chelation of Oxytetracycline and Doxycycline, EDTA method (P. Trinder) and calcium binding assay was followed. Different doses of Oxytetracycline (25 mg, 50 mg and 100 mg) and Doxycycline (25 mg, 50 mg and 100 mg) were used in EDTA method and different concentrations of calcium were used in calcium binding assay. The procedure was done according to the standard methodology.Results: The intensity of colour appear to be increased with increase in dose of the Oxytetracycline (25 mg, 50 mg, 100 mg) as the concentration of calcium binding increases. But in Doxycycline intensity of colour is more with 100 mg as compared with 25 mg and 50 mg The UV absorption spectrum of solution of Oxytetracycline (1mM) was changed after the addition of CaCl2 to provide different concentration of Ca2+ (0.1, 0.5 and 1.0 mM).  With minor shift in the absorption coefficient and no shift in wavelength were observed for Doxycycline.Conclusions: The study concludes that oxytetracycline has more calcium chelating property than doxycycline.

UV absorption spectrum and absorption cross sections of COF2at 296 K in the range 200 - 230 nm

1992 ◽  
Vol 19 (3) ◽  
pp. 281-284 ◽  
Author(s):  
Andreas Nölle ◽  
Horst Heydtmann ◽  
Richard Meller ◽  
Wolfgang Schneider ◽  
Geert K. Moortgat
Keyword(s):  
Absorption Spectrum ◽  
Cross Sections ◽  
Uv Absorption ◽  
Absorption Cross ◽  
Uv Absorption Spectrum

scholarly journals Ultraviolet irradiation of blood prevents transfusion-induced sensitization and marrow graft rejection in dogs

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 537-539 ◽  
Author(s):  
HJ Deeg ◽  
J Aprile ◽  
TC Graham ◽  
FR Appelbaum ◽  
R Storb
Keyword(s):  
Ultraviolet Irradiation ◽  
Graft Rejection ◽  
Uv Light ◽  
Canine Model ◽  
Donor Blood ◽  
Histocompatibility Antigens ◽  
Marrow Graft ◽  
Accessory Cells ◽  
In Vitro Exposure

Abstract In a canine model using DLA-identical littermate pairs, we have shown that a regimen of three transfusions of donor blood given 24, 17, and 10 days before transplant uniformly leads to marrow graft rejection, presumably due to sensitization to minor (non-DLA) histocompatibility antigens. Untransfused dogs uniformly achieve sustained engraftment. In the present study, we investigated whether the exposure of blood to ultraviolet (UV) light (220–300 nm) prior to transfusion prevented sensitization of the recipient and allowed for successful marrow engraftment. Ten dogs were each given three pretransplant transfusions from the marrow donor. Each transfusion consisted of 50 mL of whole blood exposed in vitro to UV light for a total of 1.35 J/cm2. All ten dogs achieved engraftment. In contrast, all four dogs that had received sham-exposed transfusions rejected their grafts. In vitro studies revealed that although cell viability was not affected, leukocytes contained in UV-exposed blood were unable to function as stimulator cells in mixed leukocyte cultures or as accessory cells in mitogen- stimulated cultures. These data are consistent with the hypothesis that accessory cells are involved in transfusion-induced sensitization. We conclude that in vitro exposure of blood to UV light before transfusion prevents sensitization and allows for subsequent marrow engraftment.

Transmittance Properties of Flurandrenolide Tape for Psoriasis: Helpful Adjunct to Phototherapy

2000 ◽  
Vol 4 (4) ◽  
pp. 196-198 ◽  
Author(s):  
Vijay Setaluri ◽  
Adele R. Clark ◽  
Steven R. Feldman
Keyword(s):  
Absorption Spectrum ◽  
Light Transmission ◽  
Uv Light ◽  
Uv Absorption ◽  
Puva Therapy ◽  
Affected Area ◽  
Lichen Simplex Chronicus ◽  
Uv Dose ◽  
Uvb Phototherapy

Background: Flurandrenolide tape is a valuable agent in the treatment of lichen simplex chronicus and in psoriasis. The corticosteroid is helpful for reducing the symptoms and induration of the lichen simplex chronicus lesion, and occlusion of the lesion with the tape reduces the patient's opportunity to rub and scratch the affected area. Objective: The purpose of this study was to determine to what extent flurandrenolide tape may block ultraviolet (UV) light and interfere with phototherapy of psoriasis. Methods: Flurandrenolide tape was applied to quartz spectroscopy cuvettes, and the absorption spectrum was determined using a Beckman DU-600 spectrophotometer. The effect of the tape on UV light transmission was also determined using our UVA-UVB office phototherapy unit. Results: Flurandrenolide tape has considerable UV absorption in the UVC range with less absorption in the UVB and UVA range. The transmittance is greater (less absorption) with longer wavelengths. There was greater UV absorption in the UVB range than in the UVA range. Conclusion: Although flurandrenolide tape may be left in place during PUVA therapy, adjustment of UV dose or removal of the tape is probably needed during UVB phototherapy.

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