Science.gov

Sample records for one-time reduced-fluence photodynamic

  1. Photodynamic therapy for cancer

    MedlinePlus

    ... Photoradiation therapy; Cancer of the esophagus-photodynamic; Esophageal cancer-photodynamic; Lung cancer-photodynamic ... the light at the cancer cells. PDT treats cancer in the: Lungs, using a bronchoscope Esophagus, using upper endoscopy Doctors ...

  2. Photodynamic therapy for cancer

    MedlinePlus

    ... Cancer of the esophagus-photodynamic; Esophageal cancer-photodynamic; Lung cancer-photodynamic ... the light at the cancer cells. PDT treats cancer in the: Lungs, using a bronchoscope Esophagus, using upper endoscopy Doctors ...

  3. Photodynamic Therapy

    PubMed Central

    Dougherty, Thomas J.; Gomer, Charles J.; Henderson, Barbara W.; Jori, Giulio; Kessel, David; Korbelik, Mladen; Moan, Johan; Peng, Qian

    2015-01-01

    Photodynamic therapy involves administration of a tumor-localizing photosensitizing agent, which may require metabolic synthesis (i.e., a prodrug), followed by activation of the agent by light of a specific wavelength. This therapy results in a sequence of photochemical and photobiologic processes that cause irreversible photodamage to tumor tissues. Results from preclinical and clinical studies conducted worldwide over a 25-year period have established photodynamic therapy as a useful treatment approach for some cancers. Since 1993, regulatory approval for photodynamic therapy involving use of a partially purified, commercially available hematoporphyrin derivative compound (Photofrin®) in patients with early and advanced stage cancer of the lung, digestive tract, and genitourinary tract has been obtained in Canada, The Netherlands, France, Germany, Japan, and the United States. We have attempted to conduct and present a comprehensive review of this rapidly expanding field. Mechanisms of subcellular and tumor localization of photosensitizing agents, as well as of molecular, cellular, and tumor responses associated with photodynamic therapy, are discussed. Technical issues regarding light dosimetry are also considered. PMID:9637138

  4. Regression of drusen after combined treatment using photodynamic therapy with verteporfin and ranibizumab.

    PubMed

    Novais, Eduardo Amorim; Badaró, Emmerson; Regatieri, Caio Vinicius Saito; Duker, Jay; de Oliveira Bonomo, Pedro Paulo

    2015-02-01

    Drusen are the clinical hallmark of age-related macular degeneration. The regression of these deposits in patients treated with argon, krypton, or diode laser photocoagulation has been reported previously. However, previous protocols with conventional laser for drusen may result in retinal pigment epithelium (RPE) damage and unwanted scotomas. The authors report a case of complete regression of soft drusen in a 65-year-old man with central visual loss and metamorphopsia due to a drusenoid RPE detachment and soft drusen who underwent reduced-fluence photodynamic therapy (PDT) and three monthly intravitreal injections of ranibizumab. Reduced-fluence PDT combined with anti-VEGF therapy may reduce drusen without inducing RPE cell damage. PMID:25707058

  5. Miniature, Lightweight, One-Time-Opening Valve

    NASA Technical Reports Server (NTRS)

    Jones, Jack; Wu, Juinn Jenq; Leland, Robert

    2008-01-01

    The figure depicts the main parts of a prototype miniature, lightweight, onetime- opening valve. Like some other miniature one-time-opening valves reported in previous issues of NASA Tech Briefs, this valve is opened by melting a material that blocks the flow path. This valve is designed to remain closed at some temperature between room temperature and cryogenic temperature until the time of opening. The prototype valve includes a 1/8-in. (3-mm) aluminum tube, one end of which is plugged with a solder comprising about 37 weight percent of lead and 63 weight percent of tin. The tube and the solder both have a coefficient of thermal expansion of 23 micron/m-K at room temperature. Before plugging, the interior surface of the plug end of the tube is cleaned with a commercial flux paste developed specifically for preparing aluminum for bonding with lead/tin solder. The solder is then melted into the cleaned end of the tube, forming the plug. In a test, the plugged tube was pressurized to 1,000 psi (6.9 MPa) with helium and leak-tested. It was then cooled to a temperature of 77 K (about 196 C) and again leak-tested at the same pressure. Finally, at a lower pressure, the plugged end of the tube was heated to about 200 C (the melting temperature of the solder is 183 C), causing the solder plug to be ejected (see figure). It has been estimated that in a subsequent version of the valve, the plug could be melted by electrical heating, using a nichrome wire having a mass of only 10 g.

  6. 48 CFR 225.7003-4 - One-time waiver.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false One-time waiver. 225.7003-4 Section 225.7003-4 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM... Other Statutory Restrictions on Foreign Acquisition 225.7003-4 One-time waiver. DoD may accept...

  7. One-Time Pad as a nonlinear dynamical system

    NASA Astrophysics Data System (ADS)

    Nagaraj, Nithin

    2012-11-01

    The One-Time Pad (OTP) is the only known unbreakable cipher, proved mathematically by Shannon in 1949. In spite of several practical drawbacks of using the OTP, it continues to be used in quantum cryptography, DNA cryptography and even in classical cryptography when the highest form of security is desired (other popular algorithms like RSA, ECC, AES are not even proven to be computationally secure). In this work, we prove that the OTP encryption and decryption is equivalent to finding the initial condition on a pair of binary maps (Bernoulli shift). The binary map belongs to a family of 1D nonlinear chaotic and ergodic dynamical systems known as Generalized Luröth Series (GLS). Having established these interesting connections, we construct other perfect secrecy systems on the GLS that are equivalent to the One-Time Pad, generalizing for larger alphabets. We further show that OTP encryption is related to Randomized Arithmetic Coding - a scheme for joint compression and encryption.

  8. Photodynamic therapy in dentistry.

    PubMed

    Konopka, K; Goslinski, T

    2007-08-01

    Photodynamic therapy (PDT), also known as photoradiation therapy, phototherapy, or photochemotherapy, involves the use of a photoactive dye (photosensitizer) that is activated by exposure to light of a specific wavelength in the presence of oxygen. The transfer of energy from the activated photosensitizer to available oxygen results in the formation of toxic oxygen species, such as singlet oxygen and free radicals. These very reactive chemical species can damage proteins, lipids, nucleic acids, and other cellular components. Applications of PDT in dentistry are growing rapidly: the treatment of oral cancer, bacterial and fungal infection therapies, and the photodynamic diagnosis (PDD) of the malignant transformation of oral lesions. PDT has shown potential in the treatment of oral leukoplakia, oral lichen planus, and head and neck cancer. Photodynamic antimicrobial chemotherapy (PACT) has been efficacious in the treatment of bacterial, fungal, parasitic, and viral infections. The absence of genotoxic and mutagenic effects of PDT is an important factor for long-term safety during treatment. PDT also represents a novel therapeutic approach in the management of oral biofilms. Disruption of plaque structure has important consequences for homeostasis within the biofilm. Studies are now leading toward selective photosensitizers, since killing the entire flora leaves patients open to opportunistic infections. Dentists deal with oral infections on a regular basis. The oral cavity is especially suitable for PACT, because it is relatively accessible to illumination. PMID:17652195

  9. Photodynamic immune modulation (PIM)

    NASA Astrophysics Data System (ADS)

    North, John R.; Hunt, David W. C.; Simkin, Guillermo O.; Ratkay, Leslie G.; Chan, Agnes H.; Lui, Harvey; Levy, Julia G.

    1999-09-01

    Photodynamic Therapy (PDT) is accepted for treatment of superficial and lumen-occluding tumors in regions accessible to activating light and is now known to be effective in closure of choroidal neovasculature in Age Related Macular Degeneration. PDT utilizes light absorbing drugs (photosensitizers) that generate the localized formation of reactive oxygen species after light exposure. In a number of systems, PDT has immunomodulatory effects; Photodynamic Immune Modulation (PIM). Using low- intensity photodynamic regimens applied over a large body surface area, progression of mouse autoimmune disease could be inhibited. Further, this treatment strongly inhibited the immunologically- medicated contact hypersensitivity response to topically applied chemical haptens. Immune modulation appears to result from selective targeting of activated T lymphocytes and reduction in immunostimulation by antigen presenting cells. Psoriasis, an immune-mediated skin condition, exhibits heightened epidermal cell proliferation, epidermal layer thickening and plaque formation at different body sites. In a recent clinical trial, approximately one-third of patients with psoriasis and arthritis symptoms (psoriatic arthritis) displayed a significant clinical improvement in several psoriasis-related parameters after four weekly whole-body PIM treatments with verteporfin. The safety profile was favorable. The capacity of PIM to influence other human immune disorders including rheumatoid arthritis is under extensive evaluation.

  10. Secure direct communication with a quantum one-time pad

    SciTech Connect

    Deng Fuguo; Long Guilu

    2004-05-01

    Quantum secure direct communication is the direct communication of secret messages without first producing a shared secret key. It may be used in some urgent circumstances. Here we propose a quantum secure direct communication protocol using single photons. The protocol uses batches of single photons prepared randomly in one of four different states. These single photons serve as a one-time pad which is used directly to encode the secret messages in one communication process. We also show that it is unconditionally secure. The protocol is feasible with present-day technique.

  11. Physical key-protected one-time pad

    NASA Astrophysics Data System (ADS)

    Horstmeyer, Roarke; Judkewitz, Benjamin; Vellekoop, Ivo M.; Assawaworrarit, Sid; Yang, Changhuei

    2013-12-01

    We describe an encrypted communication principle that forms a secure link between two parties without electronically saving either of their keys. Instead, random cryptographic bits are kept safe within the unique mesoscopic randomness of two volumetric scattering materials. We demonstrate how a shared set of patterned optical probes can generate 10 gigabits of statistically verified randomness between a pair of unique 2 mm3 scattering objects. This shared randomness is used to facilitate information-theoretically secure communication following a modified one-time pad protocol. Benefits of volumetric physical storage over electronic memory include the inability to probe, duplicate or selectively reset any bits without fundamentally altering the entire key space. Our ability to securely couple the randomness contained within two unique physical objects can extend to strengthen hardware required by a variety of cryptographic protocols, which is currently a critically weak link in the security pipeline of our increasingly mobile communication culture.

  12. Physical key-protected one-time pad.

    PubMed

    Horstmeyer, Roarke; Judkewitz, Benjamin; Vellekoop, Ivo M; Assawaworrarit, Sid; Yang, Changhuei

    2013-01-01

    We describe an encrypted communication principle that forms a secure link between two parties without electronically saving either of their keys. Instead, random cryptographic bits are kept safe within the unique mesoscopic randomness of two volumetric scattering materials. We demonstrate how a shared set of patterned optical probes can generate 10 gigabits of statistically verified randomness between a pair of unique 2 mm(3) scattering objects. This shared randomness is used to facilitate information-theoretically secure communication following a modified one-time pad protocol. Benefits of volumetric physical storage over electronic memory include the inability to probe, duplicate or selectively reset any bits without fundamentally altering the entire key space. Our ability to securely couple the randomness contained within two unique physical objects can extend to strengthen hardware required by a variety of cryptographic protocols, which is currently a critically weak link in the security pipeline of our increasingly mobile communication culture. PMID:24345925

  13. Physical key-protected one-time pad

    PubMed Central

    Horstmeyer, Roarke; Judkewitz, Benjamin; Vellekoop, Ivo M.; Assawaworrarit, Sid; Yang, Changhuei

    2013-01-01

    We describe an encrypted communication principle that forms a secure link between two parties without electronically saving either of their keys. Instead, random cryptographic bits are kept safe within the unique mesoscopic randomness of two volumetric scattering materials. We demonstrate how a shared set of patterned optical probes can generate 10 gigabits of statistically verified randomness between a pair of unique 2 mm3 scattering objects. This shared randomness is used to facilitate information-theoretically secure communication following a modified one-time pad protocol. Benefits of volumetric physical storage over electronic memory include the inability to probe, duplicate or selectively reset any bits without fundamentally altering the entire key space. Our ability to securely couple the randomness contained within two unique physical objects can extend to strengthen hardware required by a variety of cryptographic protocols, which is currently a critically weak link in the security pipeline of our increasingly mobile communication culture. PMID:24345925

  14. Photodynamic Therapy (PDT): PDT Mechanisms

    PubMed Central

    Allison, Ron R.

    2013-01-01

    Photodynamic therapy (PDT) is a light based therapy used to ablate tumors. As practiced in oncology a photosensitizing agent is applied and then activated by a specific wavelength and energy of light. This light energy in the presence of oxygen will lead to the creation of the photodynamic reaction which is cyto and vasculo toxic. This paper will review the mechanisms of action of PDT and how they may be manipulated to improve clinical outcome in cancer patients. PMID:23422955

  15. [Photodynamic modulation of cellular functions].

    PubMed

    Li, Yuan; Jiang, Hong-Ning; Cui, Zong-Jie

    2016-08-25

    Photodynamic action, due to the rather limited lifetime (1 μs) and effective reactive distance of singlet oxygen (< 10 nm), could subcellular-specifically regulate different cellular functions. Photodynamic action could activate permanently cholecystokinin (CCK) 1 receptors, and sensitize or desensitize other G protein-coupled receptors. The emergence in recent years of genetically- encoded protein photosensitisers has enabled more precisely-targeted photodynamic modulation of subcellular organelles and functional proteins. Protein photosensitisers (such as KillerRed, miniSOG or SOPP) expressed on the plasma membrane, mitochondria, lysosomes or endoplasmic reticulum can modulate photodynamically subcellular functions and fine-tune protein activity by targeted photooxidation. With the newly emerged active illumination technique, simultaneous photodynamic action localized at multiple sites is now possible, and the contribution of subcellular regions to the whole cell or individual cells to a cell cluster could be quantitated. Photodynamic action with protein photosensitiser will be a powerful tool for nano-manipulation in cell physiology research. PMID:27546513

  16. Photodynamic Therapy Of Cancer

    NASA Astrophysics Data System (ADS)

    Dougherty, Thomas J.

    1989-03-01

    Photodynamic therapy (PDT) has been used experimentally in cancer patients since 1976, with an estimated 3,000-4,000 patients treated world-wide, most since 1982. Phase III, comparative randomized clinical trials are under way for regulatory approval of Photofrin II, a purified version of hematoporphyrin derivative (Hpd). Several recent advances in both the clinical application of PDT and basic understanding of mechanisms are noteworthy. For example, it is now recognized that the photosensitizer undergoes photobleaching during treatment which may provide a therapeutic advantage in treatment. Clinical trials using lower drug doses seem to be consistent with this expectation. Advances in light delivery systems and dosimetry have also been achieved. It is now clear that in at least some experimental animal tumors, destruction of the vasculature system in both the tumor and surrounding normal tissue is necessary for 'cure', a process which may involve release of inflammatory and other factors. It is unclear if this is relevant to humans. Because of the problem of cutaneous photosensitivity and other factors, a search for other photo-sensitizers is being carried out by several groups, with early encouraging results being reported for certain phthalocyanines, purpurins and others.

  17. Photodynamic therapy for epilepsy

    NASA Astrophysics Data System (ADS)

    Zusman, Edie; Sidhu, Manpreet; Coon, Valerie; Scott, Nicholas; Bisland, Stuart; Tsukamoto, Tara

    2006-02-01

    Epilepsy is surgically curable if the seizure focus can be localized and does not include areas of eloquent cortex. Because epileptic cells are indistinct from surrounding brain, resection typically includes normal tissue. Using the rat kindling model of epilepsy, we evaluated Photodynamic Therapy (PDT) as a super-selective lesioning technique. We present a series of pilot studies to evaluate: 1) Protoporphyrin IX (PpIX) fluorescence, 2) the efficacy of PDT to raise seizure thresholds, 3) the safety of PDT using behavioral studies, and 4) histologic results. Bipolar electrodes were chronically implanted into the cortex and animals received successive low-level stimulation generating seizures of increasing severity. Following 5-aminolevulinic acid (ALA) administration, fully kindled rats received electrical stimulation to induce a generalized seizure. Animals were irradiated with laser light focused onto a temporal craniectomy. Our results show: 1) an increase in PpIX fluorescence in the seizure group, 2) PDT treated animals failed to demonstrate seizure activity following repeat stimulation, 3) no statistically significant difference between treated and control animals were observed on behavioral tests, 4) histology showed pyknotic hippocampal pyramidal cells in the CA3 region without areas of obvious necrosis. In conclusion, this is the first report of heightened PpIX-mediated fluorescence in epileptic brain. The selective accumulation of PpIX with laser PDT may provide a less invasive and more precise technique for obliteration of epileptic foci. PDT warrants additional research to determine if this technique may augment or replace existing procedures for the surgical management of epilepsy.

  18. Photodynamic therapy--aspects of pain management.

    PubMed

    Fink, Christine; Enk, Alexander; Gholam, Patrick

    2015-01-01

    Topical photodynamic therapy (PDT) is a highly effective and safe treatment method for actinic keratoses with an excellent cosmetic outcome and is commonly used for the therapy of large areas of photodamaged skin with multiple clinically manifest and subclinical lesions. However, the major drawback of photodynamic therapy is the pain experienced during the treatment that can be intense and sometimes even intolerable for patients, requiring interruption or termination of the process. Several strategies for controlling pain during photodynamic therapy have been studied but few effective methods are currently available. Therefore, this review puts the spotlight on predictors on pain intensity and aspects of pain management during photodynamic therapy. PMID:25640485

  19. 24 CFR 203.280 - One-time or Up-front MIP.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false One-time or Up-front MIP. 203.280... SINGLE FAMILY MORTGAGE INSURANCE Contract Rights and Obligations Mortgage Insurance Premiums-One-Time Payment § 203.280 One-time or Up-front MIP. For mortgages for which a one-time or up-front MIP is to...

  20. Treatment of rheumatoid arthritis using photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Hendrich, Christian; Diddens, Heyke C.; Nosir, Hany R.; Siebert, Werner E.

    1995-03-01

    The only early therapy of rheumatoid arthritis in orthopedic surgery is a synovectomy, which is restricted to more or less big joints. A laser-synovectomy of small joints is ineffective yet. An alternative method may be photodynamic therapy. In our study we describe the photodynamic effect of Photosan 3 in a cell culture study.

  1. Photodynamic Diagnosis and Therapy of Cancer

    SciTech Connect

    Subiel, Anna

    2010-01-05

    This paper gives brief information about photodynamic method used in diagnosis and therapy for cancer and other human body disorders. In particular it concentrates on detection and analysis of fluorescent dye, i.e. protoporphyrin IX (PpIX) and its two-photon excitation (TPE) process, which offers photodynamic method many fascinating possibilities.

  2. 24 CFR 203.281 - Calculation of one-time MIP.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Calculation of one-time MIP. 203... AUTHORITIES SINGLE FAMILY MORTGAGE INSURANCE Contract Rights and Obligations Mortgage Insurance Premiums-One-Time Payment § 203.281 Calculation of one-time MIP. (a) The applicable premium percentage...

  3. 24 CFR 888.320 - One-time Contract Rent determination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false One-time Contract Rent... Elderly or Handicapped, and Special Allocations Projects § 888.320 One-time Contract Rent determination..., as described in § 888.301(c), may request a one-time Contract Rent determination, to be effective...

  4. 24 CFR 203.283 - Refund of one-time MIP.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Refund of one-time MIP. 203.283... SINGLE FAMILY MORTGAGE INSURANCE Contract Rights and Obligations Mortgage Insurance Premiums-One-Time Payment § 203.283 Refund of one-time MIP. (a) The Commissioner shall provide for the refund to...

  5. Photodynamic antimicrobial activity of hypocrellin A.

    PubMed

    Su, Yujie; Sun, Jun; Rao, Shengqi; Cai, Yujie; Yang, Yanjun

    2011-04-01

    Antimicrobial photodynamic therapy is a recently developed therapeutic option that combines a non-toxic photosensitizer with harmless visible light to damage the microbial cell. Hypocrellin A (HA), a natural occurring lipid-soluble perylenequinone pigment, has gained considerable interest since its anticancer and antiviral activities have been reported. Here, we examined the antimicrobial activity of HA against Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Escherichia coli, Salmonella typhimurium). The results indicate that HA has a photodynamic antimicrobial activity against both Gram-positive and Gram-negative bacteria when CaCl(2) or MgCl(2) was employed. A loose binding has been established between HA and the organisms. Molecular oxygen is significantly involved in the photodynamic action of HA. Furthermore, HA maintains a photodynamic activity in terms of both types I and II reactions. Our results confirm the potential of HA to be used as a photosensitizer in antimicrobial photodynamic therapy. PMID:21300554

  6. Temperature effects in photodynamic processes

    NASA Astrophysics Data System (ADS)

    Hovhannisyan, Vladimir A.; Avetisyan, Hasmik A.; Mathevosyan, Margarita B.; Elbakyan, Egishe G.

    2005-04-01

    Photodynamic activity of several dyes on Drosophila melanogaster at different temperatures (15-35°C) inside of test-tubes was investigated. Both phototoxic sensitizers (chlorin e6, methylene blue, etc. -group A) and non active compounds (hemoglobin, brilliant green, pyronine, etc.-group B) were used. Dyes of 10-5-10-3 M concentration were added to the food for drosophila 24 hours before irradiation. Solar radiation, narrow-band halogen lamps, LEDs and laser were used as a photo-stimulator. Irradiation parameters: I <= 45mW/cm2 and 0.2photodynamic effect. This, probably, is concerned with the toxic photoproduct suppression by the inactive dye. Experimental model of drosophila allows to investigate photosensitization impact within wide temperature range, to find out the processes, when using combination of dyes, as well as to study photodynamic effect on reproductive functions of insects.

  7. Photodynamic treatment for surface sanitation

    NASA Astrophysics Data System (ADS)

    Brovko, Lubov; Romanova, Nadya A.; Leslie, Christina; Ollivier, Helene; Griffiths, Mansel W.

    2005-09-01

    The bactericidal effect of visible light illumination on bacteria treated with non-toxic photosensitizers (PS) has been shown previously, its effectiveness depended on both cell type and nature of photosensitizer used. The photosensitizer (PS)-mediated bactericidal effect of light against different types of microorganisms including vegetative bacteria (both in planktonic form and in biofilms), bacterial spores, yeasts, viruses was investigated for both cells in liquid media, and on surface. Bactericidal effect was monitored for different photosensitizer such as TBO and derivatives of rosamine at different concentrations. The possibility of using photodynamic treatment for surface sanitation was investigated.

  8. A history of photodynamic therapy.

    PubMed

    Daniell, M D; Hill, J S

    1991-05-01

    The origins of light as a therapy in medicine and surgery are traced from antiquity to the modern day. Phototherapy began in ancient Greece, Egypt and India but disappeared for many centuries, only being rediscovered by Western civilization at the beginning of the twentieth century through the Dane, Niels Finsen, and the Germans Oscar Raab and Herman von Tappeiner. The discovery of the tumour-localizing ability of haematoporphyrin, together with its phototoxic effect on tumour cells led to the development of photodynamic therapy, a promising tool in modern cancer treatment. PMID:2025186

  9. Photodynamic therapy: present and future

    NASA Astrophysics Data System (ADS)

    Waidelich, Raphaela M.

    2000-06-01

    Photodynamic therapy (PDT) involves the administration of a photosensitizing agent and its subsequent activation by light of the appropriate wavelength, resulting in destruction of cells containing the agent. PDT has been designed as a promising new modality in the treatment of various malignant and nonmalignant disease since the early 1980s. Recent chemical and physical developments have brought forth new methods of PDT. We provide an overview of photosensitizers, photobiology and photochemistry, and light sources available for PDT. Clinical and preclinical PDT studies are discussed.

  10. 24 CFR 203.280 - One-time or Up-front MIP.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false One-time or Up-front MIP. 203.280... Payment § 203.280 One-time or Up-front MIP. For mortgages for which a one-time or up-front MIP is to be... the mortgage by the Commissioner or the up-front portion of the total obligation, as...

  11. 24 CFR 203.280 - One-time or Up-front MIP.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false One-time or Up-front MIP. 203.280... Payment § 203.280 One-time or Up-front MIP. For mortgages for which a one-time or up-front MIP is to be... the mortgage by the Commissioner or the up-front portion of the total obligation, as...

  12. 24 CFR 203.280 - One-time or Up-front MIP.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false One-time or Up-front MIP. 203.280... Payment § 203.280 One-time or Up-front MIP. For mortgages for which a one-time or up-front MIP is to be... the mortgage by the Commissioner or the up-front portion of the total obligation, as...

  13. 24 CFR 203.280 - One-time or Up-front MIP.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false One-time or Up-front MIP. 203.280... Payment § 203.280 One-time or Up-front MIP. For mortgages for which a one-time or up-front MIP is to be... the mortgage by the Commissioner or the up-front portion of the total obligation, as...

  14. Vascular effect of photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Fyodorov, Svyatoslav N.; Kopayeva, V. G.; Andreev, J. B.; Ponomarev, Gelii V.; Stranadko, Eugeny P.; Suchin, H. M.

    1996-01-01

    Vascular effect of PDT has been studied in patients with corneal vascularized leucomas (10 patients) and in patients with corneal neovascularized transplant (3 patients). For vascularized leucomas the method of photodynamic therapy consisted of the local injection of dimegin (deiteroporphyrin derivative) into the space of the newly-formed vessels under operating microscope (opton) with the microneedle (diameter 200 microns) and corneal irradiation by the operating microscope light. For corneal neovascularized transplant the injection of photogem (hematoporphyrin derivative) intravenously were made with subsequent irradiation by light of dye laser (5 hours after the injection) with light density of 150 mW/cm2 for 15 minutes. In all the cases at the time of irradiation the aggregated blood flow was appeared, followed by blood flow stasis. In postoperative period the vessels disintegrated into separate fragments which disappeared completely after 10 - 15 days. Taking into account the data of light microscopy, the disappearance of the vessels took place as a result of the vascular endothelium lisis along the vascular walls. Neovascularized cornea and newly-formed vessels in tumor stroms have much in common. The vessel alterations study presented in this paper, may serve to specify the mechanism of photodynamic destruction of neovascularized stroma of tumor.

  15. Photosensitizers for photodynamic immune modulation

    NASA Astrophysics Data System (ADS)

    North, John R.; Boch, Ronald; Hunt, David W. C.; Ratkay, Leslie G.; Simkin, Guillermo O.; Tao, Jing-Song; Richter, Anna M.; Levy, Julia G.

    2000-06-01

    PDT may be an effective treatment for certain immune-mediated disorders. The immunomodulatory action of PDT is likely a consequence of effects exerted at a number of levels including stimulation of specific cell signaling pathways, selective depletion of activated immune cells, alteration of receptor expression by immune and non-immune cells, and the modulation of cytokine availability. QLT0074, a potent photosensitizer that exhibits rapid clearance kinetics in vivo, is in development for the treatment of immune disorders. In comparison to the well-characterized and structurally related photosensitizer verteporfin, lower concentrations of QLT0074 were required to induce apoptosis in human blood T cells and keratinocytes using blue light for photoactivation. Both photosensitizers triggered the stress activated protein kinase (SAPK) and p38 (HOG1) pathways but not extracellularly regulated kinase (ERK) activity in mouse Pam212 keratinocytes. In cell signaling responses, QLT0074 was active at lower concentrations than verteporfin. For all in vitro test systems, the stronger photodynamic activity of QLT0074 was associated with a greater cell uptake of this photosensitize than verteporfin. In mouse immune models, sub-erythemogenic doses of QLT0074 in combination with whole body blue light irradiation inhibited the contact hypersensitivity response and limited the development of adjuvant-induced arthritis. QLT0074 exhibits activities that indicate it may be a favorable agent for the photodynamic treatment of human immune disease.

  16. 75 FR 18835 - Submission for OMB Review; American Recovery and Reinvestment Act-One-Time Reporting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-13

    ... requirement concerning the one-time reporting, compensation requirements. A request for public comments was published in the Federal Register at 74 FR 14639, on March 31, 2009. Public comments are particularly...; American Recovery and Reinvestment Act--One-Time Reporting, Compensation Requirements AGENCY: Department...

  17. 24 CFR 888.420 - One-time Contract Rent determination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false One-time Contract Rent... Projects § 888.420 One-time Contract Rent determination. (a) Determining the amount of the new Contract Rent. Project owners eligible for retroactive payments, as described in § 888.401(c), may request a...

  18. 75 FR 22804 - Submission for OMB Review; American Recovery and Reinvestment Act-One-Time Reporting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-30

    .... SUPPLEMENTARY INFORMATION: A. Background The Notice, published in the Federal Register at 75 FR 18835, on April...; American Recovery and Reinvestment Act--One-Time Reporting, Compensation Requirements AGENCIES: Department... Recovery and Reinvestment Act--One-time Reporting, Compensation Requirements published in the...

  19. Photodynamic therapy toward selective endometrial ablation

    NASA Astrophysics Data System (ADS)

    Tadir, Yona; Tromberg, Bruce J.; Krasieva, Tatiana B.; Berns, Michael W.

    1993-05-01

    Potential applications of photodynamic therapy for endometrial disease are discussed. Experimental models that may lead to diagnosis and treatment of endometriosis as well as selective endometrial ablation are summarized.

  20. Photodynamic therapy of malignancy of skin with He-Ne laser

    NASA Astrophysics Data System (ADS)

    Zhu, Jing; Shi, Hongmin; Zhang, Hui-Guo

    2005-07-01

    Objective: Research on the photodynamic therapy of malignancy of skin with He-Ne Laser. Methods: 35 cases of skin malignancy were treated with photodynamic therapy. He-Ne laser with output power of 600 mW was used and hematoporphyrin derivative (HPD) was applied, at a dose of 5mg/kg of body. 15 patients received simple surface irradiation, 20 patients received both surface and insertion irradiation. 28 patients underwent treatment for one time, 7 patients twice. The 12 cases were basel cell carcinoma, 7 cases were squamous cell carcinoma, 4 cases were skin carcinoma in situ, 8 cases were skin Paget's disease, 1 case was Paget's disease accompanying adenoid carcinoma, 1 case malignant melanoma, 1 case red hypertrophic disease, 1 case recurrent perianal carcinoma deriving from rectum.

  1. Photodynamic Cancer Therapy - Recent Advances

    SciTech Connect

    Abrahamse, Heidi

    2011-09-22

    The basic principle of the photodynamic effect was discovered over a hundred years ago leading to the pioneering work on PDT in Europe. It was only during the 1980s, however, when 'photoradiation therapy' was investigated as a possible treatment modality for cancer. Photodynamic therapy (PDT) is a photochemotherapeutic process which requires the use of a photosensitizer (PS) that, upon entry into a cancer cell is targeted by laser irradiation to initiate a series of events that contribute to cell death. PSs are light-sensitive dyes activated by a light source at a specific wavelength and can be classified as first or second generation PSs based on its origin and synthetic pathway. The principle of PS activation lies in a photochemical reaction resulting from excitation of the PS producing singlet oxygen which in turn reacts and damages cell organelles and biomolecules required for cell function and ultimately leading to cell destruction. Several first and second generation PSs have been studied in several different cancer types in the quest to optimize treatment. PSs including haematoporphyrin derivative (HpD), aminolevulinic acid (ALA), chlorins, bacteriochlorins, phthalocyanines, naphthalocyanines, pheophorbiedes and purpurins all require selective uptake and retention by cancer cells prior to activation by a light source and subsequent cell death induction. Photodynamic diagnosis (PDD) is based on the fluorescence effect exhibited by PSs upon irradiation and is often used concurrently with PDT to detect and locate tumours. Both laser and light emitting diodes (LED) have been used for PDT depending on the location of the tumour. Internal cancers more often require the use of laser light delivery using fibre optics as delivery system while external PDT often make use of LEDs. Normal cells have a lower uptake of the PS in comparison to tumour cells, however the acute cytotoxic effect of the compound on the recovery rate of normal cells is not known. Subcellular

  2. [Photodynamic Therapy for Lung Cancer].

    PubMed

    Ohtani, Keishi; Ikeda, Norihiko

    2016-07-01

    In Japan, Photodynamic therapy (PDT) is recommended as a treatment option for centrally located early-stage lung cancers (CLELCs). It is a minimally invasive treatment with excellent anti-tumor effects. The 2nd generation photosensitizer, talaporfin sodium has strong anti-tumor effects with much less photosensitivity than porfimer sodium. Moreover, the laser equipment is compact and portable, and talaporfin sodium is now the current mainstay of PDT for lung cancer. For successful PDT, accurate evaluation of tumor extent and bronchial invasion is crucial. Detailed examination of the tumor using autofluorescence bronchoscopy and endobronchial ultrasonography or optical coherence tomography is extremely useful before PDT. At present, PDT has become the 1st choice of treatment for CLELC in institutions with the necessary equipment. It can also be effective for advanced lung cancer causing tracheobronchial obstruction. With such advances in PDT for CLELC, we are expanding the indications of PDT for not only CLELC, but also peripheral type lung cancer. PMID:27440036

  3. Antimicrobial photodynamic therapy: An overview

    PubMed Central

    Rajesh, S.; Koshi, Elizabeth; Philip, Koshi; Mohan, Aparna

    2011-01-01

    Inflammatory periodontal disease caused by dental plaque is characterized by the clinical signs of inflammation and loss of periodontal tissue support. The mechanical removal of this biofilm and adjunctive use of antibacterial disinfectants and antibiotics have been the conventional methods of periodontal therapy. But the removal of plaque and the reduction in the number of infectious organisms can be impaired in sites with difficult access. The possibility of development of resistance to antibiotics by the target organism has led to the development of a new antimicrobial concept with fewer complications. Photodynamic therapy (PDT) involves the use of low power lasers with appropriate wavelength to kill micro organisms treated with a photosensitizer drug. PDT could be a useful adjunct to mechanical as well as antibiotics in eliminating periopathogenic bacteria. PMID:22368354

  4. BODIPY Dyes In Photodynamic Therapy

    PubMed Central

    Kamkaew, Anyanee; Lim, Siang Hui; Lee, Hong Boon; Kiew, Lik Voon; Chung, Lip Yong

    2012-01-01

    BODIPY dyes tends to be highly fluorescent, but their emissions can be attenuated by adding substituents with appropriate oxidation potentials. Substituents like these have electrons to feed into photoexcited BODIPYs, quenching their fluorescence, thereby generating relatively long-lived triplet states. Singlet oxygen is formed when these triplet states interact with 3O2. In tissues, this causes cell damage in regions that are illuminated, and this is the basis of photodynamic therapy (PDT). The PDT agents that are currently approved for clinical use do not feature BODIPYs, but there are many reasons to believe that this situation will change. This review summarizes the attributes of BODIPY dyes for PDT, and in some related areas. PMID:23014776

  5. Photodynamic therapy of acne vulgaris.

    NASA Astrophysics Data System (ADS)

    Ershova, Ekaterina Y.; Karimova, Lubov N.; Kharnas, Sergey S.; Kuzmin, Sergey G.; Loschenov, Victor B.

    2003-06-01

    Photodynamic therapy (PDT) with topical 5-aminolevulinic acid (ALA) was tested for the treatment of acne vulgaris. Patients with acne were treated with ALA plus red light. Ten percent water solution of ALA was applied with 1,5-2 h occlusion and then 18-45 J/cm2 630 nm light was given. Bacterial endogenous porphyrins fluorescence also was used for acne therapy. Treatment control and diagnostics was realized by fluorescence spectra and fluorescence image. Light sources and diagnostic systems were used: semiconductor laser (λ=630 nm, Pmax=1W), (LPhT-630-01-BIOSPEC); LED system for PDT and diagnostics with fluorescent imager (λ=635 nm, P=2W, p=50 mW/cm2), (UFPh-630-01-BIOSPEC); high sensitivity CCD video camera with narrow-band wavelength filter (central wavelength 630 nm); laser electronic spectrum analyzer for fluorescent diagnostics and photodynamic therapy monitoring (LESA-01-BIOSPEC). Protoporphyrin IX (PP IX) and endogenous porphyrins concentrations were measured by fluorescence at wavelength, correspondingly, 700 nm and 650 nm. It was shown that topical ALA is converted into PP IX in hair follicles, sebaceous glands and acne scars. The amount of resulting PP IX is sufficient for effective PDT. There was good clinical response and considerable clearance of acne lesion. ALA-PDT also had good cosmetic effect in treatment acne scars. PDT with ALA and red light assist in opening corked pores, destroying Propionibacterium acnes and decreasing sebum secretion. PDT treatment associated with several adverse effects: oedema and/or erytema for 3-5 days after PDT, epidermal exfoliation from 5th to 10th day and slight pigmentation during 1 month after PDT. ALA-PDT is effective for acne and can be used despite several side effects.

  6. Selective tumor destruction with photodynamic therapy: exploitation of photodynamic thresholds

    NASA Astrophysics Data System (ADS)

    Barr, Hugh

    1991-11-01

    The uptake and distribution of the photosensitizer aluminum sulphonated phthalocyanine (AlSPc) has been studied. In a variety of experimentally induced gastrointestinal tumors the photosensitizer is retained between 24 - 48 hours after intravenous administration compared with the adjacent normal tissue in which the tumor arose. However, the maximum tumor-to- normal-tissue ratio was only 2:1. Quantitative fluorescence photometry using digital image processing, with a CCD camera and helium neon laser, was used to probe the microscopic localization of the photosensitizer in tissue sections of tumor and normal tissue. Selective localization of the photosensitizer was nonspecific in tumor stroma and there was never any significant difference between normal and neoplastic cells. Exploitation of the small differences in photosensitizer concentration, photodynamic threshold effects, and photosensitizer photodegration allows up to 2 mm of selective tumor damage to be produced in a tumor, when a similar light dose will produce no damage in adjacent normal tissue. However, selective eradication of a tumor without adjacent tissue damage will not be possible by using these methods. This paper reviews this previously reported data.

  7. Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

    PubMed Central

    Costa, Liliana; Faustino, Maria Amparo F.; Neves, Maria Graça P. M. S.; Cunha, Ângela; Almeida, Adelaide

    2012-01-01

    Photodynamic inactivation (PDI) has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i) summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii) discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process. PMID:22852040

  8. Photodynamic therapy for skin cancer

    NASA Astrophysics Data System (ADS)

    Panjehpour, Masoud; Julius, Clark E.; Hartman, Donald L.

    1996-04-01

    Photodynamic therapy was used to treat 111 lesions in 27 cases with squamous and basal cell carcinoma. There were 82 squamous cell carcinomas and 29 basal cell carcinomas. Photofrin was administered intravenously at either 1.0 mg/kg or 0.75 mg/kg. An argon/dye laser was used to deliver 630 nm light to the lesion superficially at either 215 J/cm2 or 240 J/cm2. In some cases the laser light was delivered both superficially and interstitially. The laser light was delivered two to four days after the Photofrin injection. There were 105 complete responses and 5 partial responses. One patient was lost to follow-up. Among partial responses were basal cell carcinoma on the tip of the nose and morphea basal cell carcinoma of the left cheek. Another partial response occurred in a basal cell carcinoma patient where insufficient margins were treated due to the proximity to the eye. When 0.75 mg/kg drug dose was used, the selectivity of tumor necrosis was improved. Decreased period of skin photosensitivity was documented in some cases.

  9. Can nanotechnology potentiate photodynamic therapy?

    PubMed Central

    Huang, Ying-Ying; Sharma, Sulbha K.; Dai, Tianhong; Chung, Hoon; Yaroslavsky, Anastasia; Garcia-Diaz, Maria; Chang, Julie; Chiang, Long Y.

    2015-01-01

    Photodynamic therapy (PDT) uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that can kill cancer cells and infectious microorganisms. Due to the tendency of most photosensitizers (PS) to be poorly soluble and to form nonphotoactive aggregates, drug-delivery vehicles have become of high importance. The nanotechnology revolution has provided many examples of nanoscale drug-delivery platforms that have been applied to PDT. These include liposomes, lipoplexes, nanoemulsions, micelles, polymer nanoparticles (degradable and nondegradable), and silica nanoparticles. In some cases (fullerenes and quantum dots), the actual nanoparticle itself is the PS. Targeting ligands such as antibodies and peptides can be used to increase specificity. Gold and silver nanoparticles can provide plasmonic enhancement of PDT. Two-photon excitation or optical upconversion can be used instead of one-photon excitation to increase tissue penetration at longer wavelengths. Finally, after sections on in vivo studies and nanotoxicology, we attempt to answer the title question, “can nano-technology potentiate PDT?” PMID:26361572

  10. Photodynamic Therapy in Pediatric Dentistry

    PubMed Central

    da Silva Barbosa, Patricia; Duarte, Danilo Antônio; Leite, Mariana Ferreira; de Sant' Anna, Giselle Rodrigues

    2014-01-01

    Conservation of deciduous teeth with pulp alterations caused by caries and trauma is a major therapeutic challenge in pediatric dentistry as a result of the internal anatomy and life cycle characteristic. It is essential that the root canal procedures sanitizers have a performance in eliminating bacterial. In this context, antimicrobial photodynamic therapy (PAT) is promising and emerging as adjuvant therapy in an attempt to eliminate the microorganisms persistent to chemi-mechanical preparation. Since there is presence of oxygen in cells, photosensitizer activated by light can react with molecules in its vicinity by electrons' or hydrogen's transfer, leading to microorganism death. This paper reports the case of 4-year-old patient, female, with early childhood caries. The proposed endodontic treatment incuded chemomechanical treatment allied to PAT in the decontamination of root canals using methylene blue dye 50 μg/mL during 3–5 minutes and 40 J/cm2 as energy density, taking into account the need for tissue penetration and effectiveness of PAT inside the dentinal tubules. PMID:25371829

  11. Functionalized Fullerenes in Photodynamic Therapy

    PubMed Central

    Huang, Ying-Ying; Sharma, Sulbha K.; Yin, Rui; Agrawal, Tanupriya; Chiang, Long Y.; Hamblin, Michael R.

    2014-01-01

    Since the discovery of C60 fullerene in 1985, scientists have been searching for biomedical applications of this most fascinating of molecules. The unique photophysical and photochemical properties of C60 suggested that the molecule would function well as a photosensitizer in photodynamic therapy (PDT). PDT uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that kill unwanted cells. However the extreme insolubility and hydrophobicity of pristine C60, mandated that the cage be functionalized with chemical groups that provided water solubility and biological targeting ability. It has been found that cationic quaternary ammonium groups provide both these features, and this review covers work on the use of cationic fullerenes to mediate destruction of cancer cells and pathogenic microorganisms in vitro and describes the treatment of tumors and microbial infections in mouse models. The design, synthesis, and use of simple pyrrolidinium salts, more complex decacationic chains, and light-harvesting antennae that can be attached to C60, C70 and C84 cages are covered. In the case of bacterial wound infections mice can be saved from certain death by fullerene-mediated PDT. PMID:25544837

  12. Strategies for targeted antimicrobial photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Verma, Sarika; Sallum, Ulysses; Zheng, Xiang; Hasan, Tayyaba

    2009-06-01

    The photophysics and mechanisms of cell killing by photodynamic therapy (PDT) have been extensively studied in recent years, and PDT has received regulatory approval for the treatment of a number of diseases worldwide. As the application of this treatment modality expands with regard to both anatomical sites and diseases, it is important to develop strategies for enhancing PDT outcomes. Our group has focused on developing targeting strategies to enhance PDT for both cancerous as well as anti-microbial applications. In this article, we will discuss photosensitizer modification and conjugation strategies for targeted antimicrobial photodynamic therapy.

  13. One-time tillage of no-till: Effects on nutrients, mycorrhizae, and phosphorus uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stratification of nutrient availability, especially of P, that develops with continuous no-till (NT) can affect runoff nutrient concentration and possibly nutrient uptake. The effects of composted manure application and one-time tillage of NT on the distribution of soil chemical properties, root co...

  14. 24 CFR 203.283 - Refund of one-time MIP.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Refund of one-time MIP. 203.283 Section 203.283 Housing and Urban Development Regulations Relating to Housing and Urban Development... URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER...

  15. 24 CFR 203.283 - Refund of one-time MIP.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Refund of one-time MIP. 203.283 Section 203.283 Housing and Urban Development Regulations Relating to Housing and Urban Development... URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER...

  16. 77 FR 10799 - Revised Guidance for Requesting One-Time Movement (OTM) Approvals

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Railroad Administration Revised Guidance for Requesting One-Time Movement (OTM) Approvals AGENCY... Administrator for Railroad Safety/Chief Safety Officer. These approvals are generally referred to as...

  17. 77 FR 70876 - Revised Guidance for Requesting One-Time Movement Approvals (OTMA)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Railroad Administration Revised Guidance for Requesting One-Time Movement Approvals (OTMA) AGENCY.... SUMMARY: FRA is notifying the public of the availability of revised guidance for requesting...

  18. 78 FR 54252 - Information Collection; American Recovery and Reinvestment Act-Reporting Requirements-One Time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-03

    ... FR 58389, for the number of respondents required to comply with the requirements of FAR subpart 4.15... Register on September 24, 2010, at 75 FR 58389. No public comments were received in prior years that have...; American Recovery and Reinvestment Act-- Reporting Requirements--One Time Reporting Requirements for...

  19. Inside the Black Box: What Happens on a One-Time Field Trip?

    ERIC Educational Resources Information Center

    Kraybill, Anne

    2014-01-01

    Crystal Bridges Museum of American Art opened on November 11, 2011. Located in Bentonville, Arkansas, it was the first art museum of its size in the region. Since few students had ever been to a museum, this situation provided an opportunity to causally measure the impact of a one-time art museum field trip upon student outcomes through the…

  20. 24 CFR 888.320 - One-time Contract Rent determination.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false One-time Contract Rent determination. 888.320 Section 888.320 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF THE ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT...

  1. 24 CFR 888.320 - One-time Contract Rent determination.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false One-time Contract Rent determination. 888.320 Section 888.320 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF THE ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT...

  2. Photodynamic application in neurosurgery: present and future

    NASA Astrophysics Data System (ADS)

    Kostron, Herwig

    2009-06-01

    Photodynamic techniques such as photodynamic diagnosis (PDD), fluorescence guided tumor resection (FGR) and photodynamic therapy (PDT) are currently undergoing intensive clinical investigations as adjunctive treatment for malignant brain tumours. This review provides an overview on the current clinical data and trials as well as on photosensitisers, technical developments and indications for photodynamic application in Neurosurgery. Furthermore new developments and clinical significance of FGR for neurosurgery will be discussed. Over 1000 patients were enrolled in various clinical phase I/II trials for PDT for malignant brain tumours. Despite various treatment protocols, variation of photosensitisers and light dose there is a clear trend towards prolonging median survival after one single PDT as compared to conventional therapeutic modalities. The median survival after PDT for primary glioblastoma multiforme WHO IV was 19 months and for recurrent GBM 9 months as compared to standard convential treatment which is 15 months and 3 months, respectively. FGR in combination with adjunctive radiation was significantly superior to standard surgical resection followed by radiation. The combination of FGR/PDD and intraoperative PDT increased significantly survival in recurrent glioblastoma patients. The combination of PDD/ FGR and PDT offers an exciting approach to the treatment of malignant brain tumours "to see and to treat." PDT was generally well tolerated and side effects consisted of occasionally increased intracranial pressure and prolonged skin sensitivity against direct sunlight. This review covers the current available data and draws the future potential of PDD and PDT for its application in neurosurgery.

  3. Adventures in photodynamic therapy: 1976-2008

    PubMed Central

    Kessel, David

    2010-01-01

    While the concept of photodynamic therapy dates from 1900, and there have been periodic re-discoveries, the clinical era really began with the studies by Dougherty and associates in the early 1970s. This report relates my encounter with the field of PDT, along with experimental approaches to the elucidation of pertinent phototoxic mechanisms. PMID:21037798

  4. Cost-effectiveness of one-time genetic testing to minimize lifetime adverse drug reactions.

    PubMed

    Alagoz, O; Durham, D; Kasirajan, K

    2016-04-01

    We evaluated the cost-effectiveness of one-time pharmacogenomic testing for preventing adverse drug reactions (ADRs) over a patient's lifetime. We developed a Markov-based Monte Carlo microsimulation model to represent the ADR events in the lifetime of each patient. The base-case considered a 40-year-old patient. We measured health outcomes in life years (LYs) and quality-adjusted LYs (QALYs) and estimated costs using 2013 US$. In the base-case, one-time genetic testing had an incremental cost-effectiveness ratio (ICER) of $43 165 (95% confidence interval (CI) is ($42 769,$43 561)) per additional LY and $53 680 per additional QALY (95% CI is ($53 182,$54 179)), hence under the base-case one-time genetic testing is cost-effective. The ICER values were most sensitive to the average probability of death due to ADR, reduction in ADR rate due to genetic testing, mean ADR rate and cost of genetic testing. PMID:25987241

  5. Design of True Random One-Time Pads in DNA XOR Cryptosystem

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Miki; Kojima, Hiroaki; Oiwa, Kazuhiro

    We present a new model to realize true random one-time pad (OTP) encryption using DNA self-assembly. OTP is an unbreakable cryptosystem if the pad (random key) is truly random, never reused, and kept secret. Mathematical algorithms can generate pseudo-random numbers only. "True" random numbers can be generated from a physical process such as thermal noise. In this work, we propose a new tile-colony algorithm that can utilize the DNA hybridization process as an effective source for the random key construction, and discuss the error tolerance of this method. Our results indicate that the molecular computation using DNA motifs will provide promising OTP applications.

  6. Electrical probe characteristic recovery by measuring only one time-dependent parameter

    NASA Astrophysics Data System (ADS)

    Costin, C.; Popa, G.; Anita, V.

    2016-03-01

    Two straightforward methods for recovering the current-voltage characteristic of an electrical probe are proposed. Basically, they consist of replacing the usual power supply from the probe circuit with a capacitor which can be charged or discharged by the probe current drained from the plasma. The experiment requires the registration of only one time-dependent electrical parameter, either the probe current or the probe voltage. The corresponding time-dependence of the second parameter, the probe voltage, or the probe current, respectively, can be calculated using an integral or a differential relation and the current-voltage characteristic of the probe can be obtained.

  7. Electrical probe characteristic recovery by measuring only one time-dependent parameter.

    PubMed

    Costin, C; Popa, G; Anita, V

    2016-03-01

    Two straightforward methods for recovering the current-voltage characteristic of an electrical probe are proposed. Basically, they consist of replacing the usual power supply from the probe circuit with a capacitor which can be charged or discharged by the probe current drained from the plasma. The experiment requires the registration of only one time-dependent electrical parameter, either the probe current or the probe voltage. The corresponding time-dependence of the second parameter, the probe voltage, or the probe current, respectively, can be calculated using an integral or a differential relation and the current-voltage characteristic of the probe can be obtained. PMID:27036776

  8. Methodologies for estimating one-time hazardous waste generation for capacity generation for capacity assurance planning

    SciTech Connect

    Tonn, B.; Hwang, Ho-Ling; Elliot, S.; Peretz, J.; Bohm, R.; Hendrucko, B.

    1994-04-01

    This report contains descriptions of methodologies to be used to estimate the one-time generation of hazardous waste associated with five different types of remediation programs: Superfund sites, RCRA Corrective Actions, Federal Facilities, Underground Storage Tanks, and State and Private Programs. Estimates of the amount of hazardous wastes generated from these sources to be shipped off-site to commercial hazardous waste treatment and disposal facilities will be made on a state by state basis for the years 1993, 1999, and 2013. In most cases, estimates will be made for the intervening years, also.

  9. Photodynamic therapy of diseased bone

    NASA Astrophysics Data System (ADS)

    Bisland, Stuart K.; Yee, Albert; Siewerdsen, Jeffery; Wilson, Brian C.; Burch, Shane

    2005-08-01

    Objective: Photodynamic therapy (PDT) defines the oxygen-dependent reaction that occurs upon light-mediated activation of a photosensitizing compound, culminating in the generation of cytotoxic, reactive oxygen species, predominantly, singlet oxygen. We are investigating PDT treatment of diseased bone. Methods: Using a rat model of human breast cancer (MT-1)-derived bone metastasis we confirmed the efficacy of benzoporphyrin-derivative monoacid (BPD-MA)-PDT for treating metastatic lesions within vertebrae or long bones. Results: Light administration (150 J) 15 mins after BPDMA (2.5 mg/Kg, i.v.) into the lumbar (L3) vertebra of rats resulted in complete ablation of the tumour and surrounding bone marrow 48 hrs post-PDT without paralysis. Porcine vertebrae provided a model comparable to that of human for light propagation (at 150 J/cm) and PDT response (BPD-MA; 6 mg/m2, i.v.) in non-tumour vertebrae. Precise fibre placement was afforded by 3-D cone beam computed tomography. Average penetration depth of light was 0.16 +/- 0.04 cm, however, the necrotic/non-necrotic interface extended 0.6 cm out from the treatment fiber with an average incident fluence rate of 4.3 mW/cm2. Non-necrotic tissue damage was evident 2 cm out from the treatment fiber. Current studies involving BPD-MA-PDT treatment of primary osteosarcomas in the forelimbs of dogs are very promising. Magnetic resonance imaging 24 hr post treatment reveal well circumscribed margins of treatment that encompass the entire 3-4 cm lesion. Finally, we are also interested in using 5-aminolevulinic acid (ALA) mediated PDT to treat osteomyelitis. Response to therapy was monitored as changes in bioluminescence signal of staphylococcus aureus (SA)-derived biofilms grown onto 0.5 cm lengths of wire and subjected to ALA-PDT either in vitro or in vivo upon implant into the intramedullary space of rat tibia. Transcutaneous delivery of PDT (75 J/cm2) effectively eradicated SAbiofilms within bone. Conclusions: Results support

  10. PIC Algorithm with Multiple Poisson Equation Solves During One Time Step

    NASA Astrophysics Data System (ADS)

    Ren, Junxue; Godar, Trenton; Menart, James; Mahalingam, Sudhakar; Choi, Yongjun; Loverich, John; Stoltz, Peter H.

    2015-09-01

    In order to reduce the overall computational time of a PIC (particle-in-cell) computer simulation, an attempt was made to utilize larger time step sizes by implementing multiple solutions of Poisson's equation within one time step. The hope was this would make the PIC simulation stable at larger time steps than an explicit technique can use, and using larger time steps would reduce the overall computational time, even though the computational time per time step would increase. A three-dimensional PIC code that tracks electrons and ions throughout a three-dimensional Cartesian computational domain is used to perform this study. The results of altering the number of times Poisson's equation is solved during a single time step are presented. Also, the size of the time that can be used and still maintain a stable solution is surveyed. The results indicate that using multiple Poisson solves during one time step provides some ability to use larger time steps in PIC simulations, but the increase in time step size is not significant and the overall simulation run time is not reduced

  11. 75 FR 10004 - Bureau of Educational and Cultural Affairs (ECA) Request for Grant Proposals (RFGP): One-time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... of Educational and Cultural Affairs (ECA) Request for Grant Proposals (RFGP): One-time Competitive Grants Program-- Competition B--Professional, Cultural, and Youth One-time Grants Program Announcement Type: New Grant. Funding Opportunity Number: ECA/PE/C-10-One-time-Comp. B. Catalog of Federal...

  12. Photodynamic therapy of cervical intraepithelial neoplasia

    NASA Astrophysics Data System (ADS)

    Inada, Natalia M.; Lombardi, Welington; Leite, Marieli F. M.; Trujillo, Jose R.; Kurachi, Cristina; Bagnato, Vanderlei S.

    2014-03-01

    Photodynamic therapy (PDT) is a technique that has been used for the treatment of tumors, especially in Gynecology. The photodynamic reaction is based on the production of reactive oxygen species after the activation of a photosensitizer. Advantages of the PDT in comparison to the surgical resection are: ambulatory treatment and tissue recovery highly satisfactory, through a non-invasive procedure. The cervical intraepithelial neoplasia (CIN) grades I and II presents potential indications for PDT. The aim of the proposed study is to evaluate the safety and efficacy of the PDT for the diagnostics and treatment of CIN I and II. The equipment and the photosensitizer are produced in Brazil with a representative low cost. It is possible to visualize the fluorescence of the cervix and to treat the lesions, without side effects. The proposed clinical protocol shows great potential to become a public health technique.

  13. Present status of photodynamic procedures in urology

    NASA Astrophysics Data System (ADS)

    Jocham, Dieter; Thomas, Stephen

    1994-03-01

    Since 1976, photodynamic therapy (PDT) has been used for the treatment of different stages of urothelial bladder tumors. First applications were based on the irradiation of single exophytic tumors using bare fibers for laser irradiation (630 mm) or bright white light generated e.g. from a mercury arc lamp. Clinical results of several centers demonstrated the possibility of destroying single superficially growing tumors. A new approach to the treatment of multifocal growing tumors, including the endoscopically often undetectable carcinoma in situ, was provided by the development of treatment modalities allowing for whole bladder wall irradiation. Photodynamic diagnosis (PDD) is a novel procedure for detecting flat precancerous and malignant lesions undetectable by endoscopy alone on the basis of laser- induced fluorescence.

  14. Second generation photodynamic agents: a review.

    PubMed

    Sternberg, E D; Dolphin, D

    1993-10-01

    Over the last decade, laser treatment of neoplastic diseases has become routine. The ability of these light-induced therapies to effect positive results is increased with the utilization of photosensitizing dyes. The approval of Photofrin in Canada as a first generation photodynamic therapeutic agent for the treatment of some forms of bladder cancer is being followed by the development of other agents with improved properties. At this time a number of second generation photosensitizing dyes are under study in phase I/II clinical trials. A review of the status of these trials along with mechanistic aspects is reviewed in this article. In addition, a review of the status of lasers to be utilized for photodynamic therapy gives some indication of which instruments could be considered for this therapy in the future. PMID:10146514

  15. Antitumor immune reaction elicited by photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Korbelik, Mladen

    1999-06-01

    This work examines why photodynamic therapy (PDT) is capable of eliciting a strong immune reaction against treated solid tumors. It is postulated that this phenomenon originates from the basic charter of the insult inflicted by the photodynamic treatment, which is dominated by singlet oxygen-mediated oxidative stress. The early event associated with this initial impact, which is of major relevance for the development of immune response, is the generation of photo-oxidative lesions responsible for the activation of cellular signal transduction pathways and consequent induction of stress proteins. Importantly, these lesions, as well as other types of PDT mediated oxidative injury, have a strong pro-inflammatory character. It is suggested that the antitumor immune response is primed and propagated by the PDT-induced inflammatory process. Of critical importance for the immune recognition of treated tumor is the generation of large amounts of cancer cell debris that occurs rapidly following PDT treatment.

  16. Heat-shock Proteins and Photodynamic Therapy

    NASA Astrophysics Data System (ADS)

    Baylis, Joanne; Downs, Craig A.; Jones, Linda R.; Heckathorn, Scott A.

    1998-11-01

    Many cancer treatments, such as photodynamic therapy, generate active oxygen species, often in the mitochondria. These oxygen species adversely react with cellular processes, thereby destroying cancer cells and tissue. Heat-shock proteins are up-regulated in response to heat stress or other environmental stresses and are known to protect cells from active oxygen species. In tumor cells, heat-shock proteins accumulate in the mitochondria under non-stress conditions at higher levels than in normal cells. The objective of our work is to determine whether specific mitochondrial heat-shock proteins are responsible for the increased resistance of cancer cells to oxidative-based anti-cancer therapies. We will first determine which heat-shock proteins accumulate in the mitochondria of cancer cells (lung carcinomas). We will determine if the over-expression of specific heat-shock proteins in the mitochondria can protect cells from Photofrin®-mediated photodynamic therapy through protection of mitochondrial electron transport.

  17. Analysis of Forgery Attack on One-Time Proxy Signature and the Improvement

    NASA Astrophysics Data System (ADS)

    Wang, Tian-Yin; Wei, Zong-Li

    2016-02-01

    In a recent paper, Yang et al. (Quant. Inf. Process. 13(9), 2007-2016, 2014) analyzed the security of one-time proxy signature scheme Wang and Wei (Quant. Inf. Process. 11(2), 455-463, 2012) and pointed out that it cannot satisfy the security requirements of unforgeability and undeniability because an eavesdropper Eve can forge a valid proxy signature on a message chosen by herself. However, we find that the so-called proxy message-signature pair forged by Eve is issued by the proxy signer in fact, and anybody can obtain it as a requester, which means that the forgery attack is not considered as a successful attack. Therefore, the conclusion that this scheme cannot satisfy the security requirements of proxy signature against forging and denying is not appropriate in this sense. Finally, we study the reason for the misunderstanding and clarify the security requirements for proxy signatures.

  18. Request for One-Time Shipment of 32 Watt PU-328 Source in 9968 Packaging

    SciTech Connect

    Massey, W.M.

    1998-11-25

    The 9968 package is designed for surface shipment of fissile and other radioactive materials where a high degree of double containment is required. The use of the 9968 radioactive material package for a one time shipment of a 32 watt heat source versus the SARP approved maximum 30 watt heat source is addressed in this report. The analyses show that the small increase in heat load from 30 watts to 32 watts does not substantially increase internal temperatures or pressures that would approach limits for the package. Also, the weight of the content is within the current 9968 package limits. It is concluded that the 32-watt heat source can be safely shipped in the 9968 package and therefore a waiver to ship the source is justified.

  19. Privacy-Preserving Authentication of Users with Smart Cards Using One-Time Credentials

    NASA Astrophysics Data System (ADS)

    Park, Jun-Cheol

    User privacy preservation is critical to prevent many sophisticated attacks that are based on the user's server access patterns and ID-related information. We propose a password-based user authentication scheme that provides strong privacy protection using one-time credentials. It eliminates the possibility of tracing a user's authentication history and hides the user's ID and password even from servers. In addition, it is resistant against user impersonation even if both a server's verification database and a user's smart card storage are disclosed. We also provide a revocation scheme for a user to promptly invalidate the user's credentials on a server when the user's smart card is compromised. The schemes use lightweight operations only such as computing hashes and bitwise XORs.

  20. Photodynamic therapy for occluded biliary metal stents

    NASA Astrophysics Data System (ADS)

    Roche, Joseph V. E.; Krasner, Neville; Sturgess, R.

    1999-02-01

    In this abstract we describe the use of photodynamic therapy (PDT) to recanalize occluded biliary metal stents. In patients with jaundice secondary to obstructed metal stents PDT was carried out 72 hours after the administration of m THPC. Red laser light at 652 nm was delivered endoscopically at an energy intensity of 50 J/cm. A week later endoscopic retrograde cholangiogram showed complete recanalization of the metal stent.

  1. [Photodynamic therapy: non-oncologic indications].

    PubMed

    Karrer, S; Szeimies, R-M

    2007-07-01

    While efficacy of topical photodynamic therapy (PDT) for the treatment of superficial non-melanoma skin cancer is already well-proven by several controlled clinical trials, there are only a few controlled studies showing efficacy of PDT for non-oncologic skin disorders. This report provides information on the use of PDT for inflammatory skin disorders, disorders of the pilosebaceous unit, infections of the skin, sclerotic skin diseases and cosmetic indications. PMID:17546432

  2. Photodynamic therapy for pododermatitis in penguins.

    PubMed

    Sellera, Fábio Parra; Sabino, Caetano Padial; Ribeiro, Martha Simões; Fernandes, Loriê Tukamoto; Pogliani, Fabio Celidonio; Teixeira, Carlos Roberto; Dutra, Gustavo Henrique Pereira; Nascimento, Cristiane Lassálvia

    2014-01-01

    Pododermatitis is currently one of most frequent and important clinical complications in seabirds kept in captivity or in rehabilitation centers. In this study, five Magellanic penguins with previous pododermatitis lesions on their footpad were treated with photodynamic therapy (PDT). All PDT treated lesions successfully regressed and no recurrence was observed during the 6-month follow-up period. PDT seems to be an inexpensive and effective alternative treatment for pododermatitis in Magellanic penguins encouraging further research on this topic. PMID:24888264

  3. A one-time opportunity to expand the market for premium efficiency motors

    SciTech Connect

    Gordon, F.; Tumidaj, L.; Hoernlein, D.; Coakley, S.

    1997-07-01

    A mid-Atlantic utility conducted a detailed research study on their motors market. The study showed that their motor loads come mostly from motors under 50 horsepower, and predominantly from industry. The proportion of premium-efficiency motor sales is very low relative to other areas which, unlike this utility's service territory, have a history of rebate programs. Most sales in this utility's territory are for replacement motors. Manufacturers are planning to create new lines of motors which meet the 1997 federal minimum motor-efficiency manufacturing standard, but are less efficient than premium motors. Few of these motors are on the market yet. The mandatory federal efficiency standard creates a unique, one-time situation where premium-efficiency motors will be a better-established and more familiar product among customers and vendors than less efficient motors. The utility has begun a motors rebate and technical assistance program which is intended to use this one-time opportunity to significantly expand the market for premium motors. Rebates are tied to the new Consortium for Energy Efficiency motor standards to ensure a common message to manufacturers among utilities. While the majority of premium motors available locally already meet the standard, this will encourage manufacturers to bring the rest of their offerings in line. Like many motors programs, this program will offer rebates, marketing, and technical assistance. However, the program design calls for a short-term (three year), very intense effort, including a rebate set at 100% of incremental cost, a short-term vendor bonus, and intensive marketing to large customers. Additionally, the large savings per motor in 1997 (when the baseline is inefficient standard motors) will justify a more generous payment in the first year. Many other US utility motor rebate programs have offered less generous incentives and used less intensive marketing, but have had only marginal impacts on markets (often 20

  4. Photoangioplasty: new applications of photodynamic therapy in atherosclerosis

    NASA Astrophysics Data System (ADS)

    Rockson, Stanley G.

    2000-05-01

    Atherosclerosis has traditionally held appeal as a pathologic entity in which photodynamic therapy might arrest or reverse the manifestations of disease. Earlier attempts to bring photodynamic therapy to the human clinical arena were hampered by the limitations of the photosensitizers under investigation, including the propensity to phototoxic manifestations and light-induced trauma to surrounding, normal vascular tissues. Many of these inherent limitations may be circumvented by newer photosensitizers that are activated at longer, more optimal wavelengths of light energy. Advances in fiberoptic catheter design for the endovascular delivery of light have also contributed to the greater applicability of photodynamic therapy to human atherosclerosis. Initial experiences with one family of photosensitizers, the texaphyrins, indicate that photodynamic therapy of human peripheral arterial atherosclerosis is feasible, safe, and well-tolerated. Photodynamic therapy of atherosclerosis holds promise for the treatment of de novo atherosclerosis and may have future applicability in the treatment, and perhaps prevention, of restenosis.

  5. Pulse mode of laser photodynamic treatment induced cell apoptosis.

    PubMed

    Klimenko, Vladimir V; Knyazev, Nickolay A; Moiseenko, Fedor V; Rusanov, Anatoliy A; Bogdanov, Alexey A; Dubina, Michael V

    2016-03-01

    One of the factors limiting photodynamic therapy (PDT) is hypoxia in tumor cells during photodynamic action. PDT with pulse mode irradiation and appropriate irradiation parameters could be more effective in the singlet oxygen generation and tissue re-oxygenation than continuous wave (CW) mode. We theoretically demonstrate differences between the cumulative singlet oxygen concentration in PDT using pulse mode and CW mode of laser irradiation. In vitro experimental results show that photodynamic treatment with pulse mode irradiation has similar cytotoxicity to CW mode and induces mainly cell apoptosis, whereas CW mode induces necrotic cell death. We assume that the cumulative singlet oxygen concentration and the temporal distribution of singlet oxygen are important in photodynamic cytotoxicity and apoptosis initiation. We expect our research may improve irradiation protocols and photodynamic therapy efficiency. PMID:26790610

  6. A 4-kbit low-cost antifuse one-time programmable memory macro for embedded applications

    NASA Astrophysics Data System (ADS)

    Xian, Li; Huicai, Zhong; Cheng, Jia; Xin, Li

    2014-05-01

    A 4-kbit low-cost one-time programmable (OTP) memory macro for embedded applications is designed and implemented in a 0.18-μm standard CMOS process. The area of the proposed 1.5 transistor (1.5T) OTP cell is 2.13 μm2, which is a 49.3% size reduction compared to the previously reported cells. The 1.5T cell is fabricated and measured and shows a large programming window without any disturbance. A novel high voltage switch (HVSW) circuit is also proposed to make sure the OTP macro, implemented in a standard CMOS process, works reliably with the high program voltage. The OTP macro is embedded in negative radio frequency identification (RFID) tags. The full chip size, including the analog front-end, digital controller and the 4-kbit OTP macro, is 600 × 600 μm2. The 4-kbit OTP macro only consumes 200 × 260 μm2. The measurement shows a 100% program yield by adjusting the program time and has obvious advantages in the core area and power consumption compared to the reported 3T and 2T OTP cores.

  7. Security enhanced optical one-time password authentication method by using digital holography

    NASA Astrophysics Data System (ADS)

    Gil, Sang Keun; Jeon, Seok Hee; Jeong, Jong Rae

    2015-03-01

    We propose a new optical one-time password(OTP) authentication method by using digital holography, which enhances security strength in the cryptosystem compared to the conventional electronic OTP method. In this paper, a challenge-response optical OTP authentication based on two-factor authentication is presented by 2-step quadrature phase-shifting digital holography using orthogonal polarization, and two-way authentication is also performed using the challenge-response handshake in both directions. The ID (identification), PW (password) and OTP information are encrypted with a shared key by applying phase-shifting digital holography, and these encrypted information are verified each other by the shared key. Because the encrypted digital holograms which are transmitted to the other party are expressed as random distribution, it guards against a replay attack and results in higher security level. Optically, encrypted digital hologram in our method is Fourier transform hologram and is recorded on CCD with 256 gray-level quantized intensities. The proposed method has an advantage that it does not need a time-synchronized OTP and can be applied to various security services. Computer experiments show that the proposed method is suitable for high secure OTP authentication.

  8. System requirements for one-time-use ENRAF control panel software

    SciTech Connect

    HUBER, J.H.

    1999-08-19

    An Enraf Densitometer is installed on tank 241-AY-102. The Densitometer will frequently be tasked to obtain and log density profiles. The activity can be effected a number of ways. Enraf Incorporated provides a software package called ''Logger18'' to its customers for the purpose of in-shop testing of their gauges. Logger18 is capable of accepting an input file which can direct the gauge to obtain a density profile for a given tank level and bottom limit. Logger18 is a complex, DOS based program which will require trained technicians and/or tank farm entries to obtain the data. ALARA considerations have prompted the development of a more user-friendly, computer-based interface to the Enraf densitometers. This document records the plan by which this new Enraf data acquisition software will be developed, reviewed, verified, and released. This plan applies to the development and implementation of a one-time-use software program, which will be called ''Enraf Control Panel.'' The software will be primarily used for remote operation of Enraf Densitometers for the purpose of obtaining and logging tank product density profiles.

  9. Vertically Stackable Novel One-Time Programmable Nonvolatile Memory Devices Based on Dielectric Breakdown Mechanism

    NASA Astrophysics Data System (ADS)

    Cho, Seongjae; Lee, Jung Hoon; Ryoo, Kyung-Chang; Jung, Sunghun; Lee, Jong-Ho; Park, Byung-Gook

    2011-12-01

    In this paper, a novel one-time programmable (OTP) nonvolatile memory (NVM) device and its array structures based on silicon technology are proposed. There have been many features of OTP NVM devices utilizing various combinations of channel, breakdown region, barrier, and contact materials. However, this invention can be realized by simple materials and fabrication methods: it is silicon-based materials and fully compatible with the conventional CMOS process. An individual memory cell is a silicon diode vertically integrated. Historically, OTP memories were widely used for read-only-memory (ROM) in the central processing unit (CPU) of the computer systems. By implanting the nanoscale fabrication technology into the concept of OTP memory, innovative high-density NVM appliances for massive storage media becomes very promising. The program operation is performed by breaking down the thin oxide layer between pn doped structure and wordline (WL) and its state can be sensed by the leakage current through the broken oxide. Since this invention is based on neither transistor structure nor charge-based mechanism, it is highly reliable and functional for the ultra-large scale integration. The feasibility of its stacked array will be also checked.

  10. One-time collision arbitration algorithm in radio-frequency identification based on the Manchester code

    NASA Astrophysics Data System (ADS)

    Liu, Chen-Chung; Chan, Yin-Tsung

    2011-02-01

    In radio-requency identification (RFID) systems, when multiple tags transmit data to a reader simultaneously, these data may collide and create unsuccessful identifications; hence, anticollision algorithms are needed to reduce collisions (collision cycles) to improve the tag identification speed. We propose a one-time collision arbitration algorithm to reduce both the number of collisions and the time consumption for tags' identification in RFID. The proposed algorithm uses Manchester coding to detect the locations of collided bits, uses the divide-and-conquer strategy to find the structure of colliding bits to generate 96-bit query strings as the 96-bit candidate query strings (96BCQSs), and uses query-tree anticollision schemes with 96BCQSs to identify tags. The performance analysis and experimental results show that the proposed algorithm has three advantages: (i) reducing the number of collisions to only one, so that the time complexity of tag identification is the simplest O(1), (ii) storing identified identification numbers (IDs) and the 96BCQSs in a register to save the used memory, and (iii) resulting in the number of bits transmitted by both the reader and tags being evidently less than the other algorithms in one-tag identification or in all tags identification.

  11. 75 FR 17919 - Submission for OMB Review; American Recovery and Reinvestment Act-One-time Reporting Requirements...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-08

    ... collection requirement concerning the American Recovery and Reinvestment Act--One-time Reporting Requirements for Prime Contractors. A request for public comments was published in the Federal Register at 74 FR...; American Recovery and Reinvestment Act--One-time Reporting Requirements for Prime Contractors...

  12. 75 FR 22805 - Submission for OMB Review; American Recovery and Reinvestment Act-One-Time Reporting Requirements...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-30

    ..., withdrawal. SUPPLEMENTARY INFORMATION: A. Background The Notice, published in the Federal Register at 75 FR...; American Recovery and Reinvestment Act--One-Time Reporting Requirements for Prime Contractors AGENCIES... Recovery and Reinvestment Act--One-time Reporting Requirements for Prime Contractors published in...

  13. Photodynamic therapy for treatment subretinal neovascularization

    NASA Astrophysics Data System (ADS)

    Avetisov, Sergey E.; Budzinskaja, Maria V.; Kiseleva, Tatyana N.; Balatskaya, Natalia V.; Gurova, Irina V.; Loschenov, Viktor B.; Shevchik, Sergey A.; Kuzmin, Sergey G.; Vorozhtsov, Georgy N.

    2007-07-01

    This work are devoted our experience with photodynamic therapy (PDT) with <> for patients with choroidal neovascularization (CNV). 18 patients with subfoveal CNV in age-related macular degeneration (AMD), 24 patients with subfoveal CNV in pathological myopia (PM) and 4 patients with subfoveal CNV associated with toxoplasmic retinochoroiditis were observed. CNV was 100% classic in all study patients. Standardized protocol refraction, visual acuity testing, ophthalmologic examinations, biomicroscopy, fluorescein angiography, and ultrasonography were performed before treatment and 1 month, 3 months, 6 months, and 1 year after treatment; were used to evaluate the results of photodynamic therapy with <> (0.02% solution of mixture sulfonated aluminium phtalocyanine 0.05 mg/kg, intravenously). A diode laser (<>, Inc, Moscow) was used operating in the range of 675 nm. Need for retreatment was based on fluorescein angiographic evidence of leakage at 3-month follow-up intervals. At 3, 6, 9 month 26 (56.5%) patients had significant improvement in the mean visual acuity. At the end of the 12-month minimal fluorescein leakage from choroidal neovascularization was seen in 12 (26.1%) patients and the mean visual acuity was slightly worse than 0.2 which was not statistically significant as compared with the baseline visual acuity. Patients with fluorescein leakage from CNV underwent repeated PDT with <>. 3D-mode ultrasound shown the decreasing thickness of chorioretinal complex in CNV area. Photodynamic therapy with <> can safely reduce the risk of severe vision loss in patients with predominantly classic subfoveal choroidal neovascularization secondary to AMD, PM and toxoplasmic retinochoroiditis.

  14. In-office Painless Aminolevulinic Acid Photodynamic Therapy

    PubMed Central

    2016-01-01

    Objective: To evaluate the efficacy, safety, and pain of in-office “painless” aminolevulinic acid photodynamic therapy aimed at decreasing treatment-associated pain in patients undergoing removal of actinic keratoses. Design: Prospective split-face study comparing short aminolevulinic acid incubation times of 15 minutes followed by extended exposure (60 minutes) of continuous blue light versus conventional aminolevulinic acid photodynamic therapy. Prospective assessment of pain in patients undergoing in-office “painless” aminolevulinic acid photodynamic therapy. Setting: Clinical practice office. Participants: Three patients with actinic keratoses participated in the split-face study and 101 in the pain assessment study. Measurements: Evaluations in the split-face study included removal of actinic keratoses, skin temperature, and pain measured on a 10-point visual analog scale. Pain was assessed using the visual analog scale in the pain assessment study. Results: In the split-face study, in-office “painless” aminolevulinic acid photodynamic therapy resulted in a 52-percent reduction in lesions versus 44 percent for conventional aminolevulinic acid photodynamic therapy. Maximum pain scores of in-office “painless” aminolevulinic acid photodynamic therapy were all 0 at each time point, and the average score for conventional aminolevulinic acid photodynamic therapy was 7. Baseline skin temperatures increased from a baseline of 29 to 32°C to 34 to 35°C by minute 10 of blue light activation on both sides of the face. Results from the pain assessment study indicated no or minimal (scores 0-2) pain in nearly all patients who received in-office “painless” aminolevulinic acid photodynamic therapy as monotherapy or in combination with 5-fluoruacil or imiquimod used as pretreatments. Conclusions: In-office “painless” aminolevulinic acid photodynamic therapy appears to be effective for removing actinic keratoses and is associated with little or no pain

  15. Flexible textile light diffuser for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Selm, Barbel; Camenzind, Martin

    2005-03-01

    In this article a new medical application is introduced using textile production techniques to deliver a defined radiation dose. The advantage for photodynamic therapy (PDT) is that a flat luminous textile structure can homogeneously illuminate unequal body surfaces. The optical properties of this two-dimensional luminous pad are characterized with a set of bench-scale tests. In vitro investigations on petri dishes with cultivated cells and first clinical tests on animal patients are promising. In addition first measurement results are presented together with an outlook to future developments.

  16. Measurements Of Singlet Oxygen In Photodynamic Therapy

    NASA Astrophysics Data System (ADS)

    Profio, A. E.; Shu, Kuang-Hsien

    1989-06-01

    Photochemical reactions are used in photodynamic therapy of cancer and other disease. The cytotoxic agent in photochemotherapy is usually singlet oxygen. Thus measurements of singlet oxygen production or concentration may allow prediction of the biological response. The decrease in fluorescence of L-tryptophan because of reaction with singlet oxygen, the decrease in absorbance of a dye such as RNO subject to secondary oxidation by singlet oxygen, and the decrease in fluorescence of the most common photosensitizer, dihematoporphyrin ether/ester (DHE) because of photobleaching, have been investigated in solutions in vitro. The most promising method for dosimetry and prediction of biological response appears to be the photobleaching of DHE.

  17. Endoscopic photodynamic therapy (PDT) for oesophageal cancer.

    PubMed

    Moghissi, Keyvan

    2006-06-01

    Endoscopic photodynamic therapy (PDT) is undertaken only when tumour is visible endoscopically with malignancy biopsy confirmed. Patients will be either Group A: inoperable cases with locally advanced cancer when the aim is palliation of dysphagia, or Group E: patients with early stage I-II disease who are unsuitable for surgery or decline operation, when the intent is curative. Following assessment for suitability for PDT and counselling, Photofrin 2mg/(kgbw) is administered 24-72h before endoscopic illumination using a Diode 630nm laser. Illumination may be either interstitial or intraluminal at a dose of 100-200J/cm. PMID:25049097

  18. Hormonal component of tumor photodynamic therapy response

    NASA Astrophysics Data System (ADS)

    Korbelik, Mladen; Merchant, Soroush

    2008-02-01

    The involvement of adrenal glucocorticoid hormones in the response of the treatment of solid tumors by photodynamic therapy (PDT) comes from the induction of acute phase response by this modality. This adrenal gland activity is orchestrated through the engagement of the hypothalamic-pituitary-adrenal hormonal axis incited by stress signals emanating from the PDT-treated tumor. Glucocorticoid hormone activity engendered within the context of PDT-induced acute phase response performs multiple important functions; among other involvements they beget acute phase reactant production, systemic neutrophil mobilization, and control the production of inflammation-modulating and immunoregulatory proteins.

  19. Photodynamic therapy and anti-tumour immunity

    PubMed Central

    Castano, Ana P.; Mroz, Pawel; Hamblin, Michael R.

    2010-01-01

    Photodynamic therapy (PDT) uses non-toxic photosensitizers and harmless visible light in combination with oxygen to produce cytotoxic reactive oxygen species that kill malignant cells by apoptosis and/or necrosis, shut down the tumour microvasculature and stimulate the host immune system. In contrast to surgery, radiotherapy and chemotherapy that are mostly immunosuppressive, PDT causes acute inflammation, expression of heat-shock proteins, invasion and infiltration of the tumour by leukocytes, and might increase the presentation of tumour-derived antigens to T cells. PMID:16794636

  20. Photodynamic dosimetry in the treatment of periodontitis

    NASA Astrophysics Data System (ADS)

    Andersen, Roger C.; Loebel, Nicolas G.; Andersen, Dane M.

    2009-06-01

    Photodynamic therapy has been demonstrated to effectively kill human periopathogens in vitro. However, the translation of in vitro work to in vivo clinical efficacy has been difficult due to the number of variables present in any given patient. Parameters such as photosensitizer concentration, duration of light therapy and amount of light delivered to the target tissue all play a role in the dose response of PDT in vivo. In this 121 patient study we kept all parameters the same except for light dose which was delivered at either 150 mW or 220 mW. This clearly demonstrated the clinical benefits of a higher light dose in the treatment of periodontitis.

  1. Acceleration Of Wound Healing Ny Photodynamic Therapy

    SciTech Connect

    Hasan, Tayyaba; Hamblin, Michael R.; Trauner, Kenneth

    2000-08-22

    Disclosed is a method for accelerating wound healing in a mammal. The method includes identifying an unhealed wound site or partially-healed wound site in a mammal; administering a photosensitizer to the mammal; waiting for a time period wherein the photosensitizer reaches an effective tissue concentration at the wound site; and photoactivating the photosensitizer at the wound site. The dose of photodynamic therapy is selected to stimulate the production of one or more growth factor by cells at the wound site, without causing tissue destruction.

  2. Photosensitizer and light diffusion through dentin in photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Nogueira, Ana C.; Graciano, Ariane X.; Nagata, Juliana Y.; Fujimaki, Mitsue; Terada, Raquel S. S.; Bento, Antonio C.; Astrath, Nelson G. C.; Baesso, Mauro L.

    2013-05-01

    Photodynamic therapy has been considered a potential antimicrobial modality against oral infections, including dental caries. A model to estimate the penetration of both photosensitizers and light through human dentin, a factor of interest in photodynamic therapy, is proposed. The photoacoustic spectroscopy technique was used to evaluate in vitro dentin permeability of three different photosensitizers. Using the dentin optical absorption and scattering coefficients, it was possible to propose a semi-quantitative model predicting both photosensitizer and light doses within dentin. The graphic illustrations obtained provided guidelines that may be useful in photodynamic therapy protocols used as antimicrobial tools in caries lesions.

  3. Differential cell photosensitivity following porphyrin photodynamic therapy.

    PubMed

    Gomer, C J; Rucker, N; Murphree, A L

    1988-08-15

    Experiments were performed to determine if differences in porphyrin photosensitivity could be observed for cells with varying efficiency in DNA damage repair, as well as for cells which make up components of the vasculature. Photofrin II is undergoing current clinical evaluation for photodynamic therapy of solid tumors, and therefore the retention, dark toxicity, and photosensitizing effects of this drug on human DNA repair-deficient fibroblasts (ataxia telangiectasia and xeroderma pigmentosum) were compared to normal human fibroblasts. In addition, bovine cells of endothelial, smooth muscle, and fibroblast origin were compared for porphyrin retention, toxicity, and photosensitivity. All human fibroblasts exhibited porphyrin-induced dark toxicity, but there were no significant differences in photosensitization or porphyrin retention for any of these cell lines. However, bovine endothelial cells were considerably more photosensitive than smooth muscle or fibroblast cells treated under identical conditions. All bovine cells accumulated similar levels of porphyrin, and therefore the increased sensitivity of the endothelial cells was not due to differences in porphyrin retention. These results provide additional evidence that nuclear damage and/or repair is not a dominant factor in the cytotoxicity induced by porphyrin photosensitization. In addition, these results indicate that endothelial cell photosensitivity may play a role in the vascular damage observed following photodynamic therapy. PMID:2969280

  4. Fighting fish parasites with photodynamically active chlorophyllin.

    PubMed

    Häder, D-P; Schmidl, J; Hilbig, R; Oberle, M; Wedekind, H; Richter, P

    2016-06-01

    Water-soluble chlorophyll (chlorophyllin) was used in a phototoxic reaction against a number of fish ectoparasites such as Ichtyobodo, Dactylogyrus, Trichodina, and Argulus. Chlorophyllin is applied to the water at concentrations of several micrograms per milliliter for a predefined incubation time, and afterwards, the parasites are exposed to simulated solar radiation. Application in the dark caused only little damage to the parasites; likewise, light exposure without the addition of the photosensitizer was ineffective. In Ichthyobodo, 2 μg/mL proved sufficient with subsequent simulated solar radiation to almost quantitatively kill the parasites, while in Dactylogyrus, a concentration of about 6 μg/mL was necessary. The LD50 value for this parasite was 1.02 μg/mL. Trichodina could be almost completely eliminated at 2 μg/mL. Only in the parasitic crustacean Argulus, no killing could be achieved by a photodynamic reaction using chlorophyllin. Chlorophyllin is non-toxic, biodegradable, and can be produced at low cost. Therefore, we propose that chlorophyllin (or other photodynamic substances) are a possible effective countermeasure against several ectoparasites in ponds and aquaculture since chemical remedies are either forbidden and/or ineffective. PMID:26936032

  5. Drug Carrier for Photodynamic Cancer Therapy

    PubMed Central

    Debele, Tilahun Ayane; Peng, Sydney; Tsai, Hsieh-Chih

    2015-01-01

    Photodynamic therapy (PDT) is a non-invasive combinatorial therapeutic modality using light, photosensitizer (PS), and oxygen used for the treatment of cancer and other diseases. When PSs in cells are exposed to specific wavelengths of light, they are transformed from the singlet ground state (S0) to an excited singlet state (S1–Sn), followed by intersystem crossing to an excited triplet state (T1). The energy transferred from T1 to biological substrates and molecular oxygen, via type I and II reactions, generates reactive oxygen species, (1O2, H2O2, O2*, HO*), which causes cellular damage that leads to tumor cell death through necrosis or apoptosis. The solubility, selectivity, and targeting of photosensitizers are important factors that must be considered in PDT. Nano-formulating PSs with organic and inorganic nanoparticles poses as potential strategy to satisfy the requirements of an ideal PDT system. In this review, we summarize several organic and inorganic PS carriers that have been studied to enhance the efficacy of photodynamic therapy against cancer. PMID:26389879

  6. Photonic metallic nanostructures in photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Ion, Rodica-Mariana; Fierascu, R. C.; Dumitriu, Irina

    2009-01-01

    Plasmons are resonant modes that involve the interaction between free charges and light. Nanoparticle-based photonic explorers have been developed for photodynamic therapy (PDT). PDT has been widely used in both oncological (e.g., tumors) and nononcological (e.g., age-related macular degeneration, localized infection, and nonmalignant skin conditions) applications. Three primary components are involved in PDT: light, a photosensitizing drug, and oxygen. The photosensitizer adsorbs light energy, which it then transfers to molecular oxygen to create an activated form of oxygen called singlet oxygen. The singlet oxygen is a cytotoxic agent and reacts rapidly with cellular components to cause damage that ultimately leads to cell death and tumor destruction. The changed topography of the film surface after deposition is caused by a local material transport and a material separation between formed particles (probably AgNO3) and an embedding polymer matrix as chitosan. This paper focuses on the current use of injectable in situ Au/(Ag)/chitosan hydrogels in cancer photodynamic treatment. Formulation protocols for their cytotoxic properties, their effect on cell growth in vitro and inhibition of tumor growth in vivo using mouse models, are discussed.

  7. Inhibition of Endocytic Processes by Photodynamic Therapy

    PubMed Central

    Kessel, David

    2011-01-01

    Background and Objective Recent studies have demonstrated an effect of photodamage on the endocytic pathway involved in recycling of membrane components. Using a series of agents with known sub-cellular targets, we explored the determinants of photodynamic inhibition of endocytic processes in three cell lines: a murine leukemia, a murine hepatoma and a non-malignant epithelial cell line of human origin. Study Design/Materials and Methods The PI-3 kinase antagonist wortmannin blocks endosomal processing pathway dependent on this enzyme, providing an indication of the ‘flux’ of endocytosis. Microscopic observations were used to assess the effect of photodamage on this pathway. Photosensitizing agents specific for mitochondrial, endoplasmic reticulum (ER), lysosomal and endosomal photodamage were employed. Conclusions Sub-lethal photodamage directed against endosomes or lysosomes interrupted early steps in this endocytic process in the hepatoma cell line. A mechanism for these effects is proposed. Mitochondrial photodamage could interrupt endocytosis, but at levels that also induced apoptosis. ER photodamage did not affect endocytosis even at lethal levels. Somewhat similar results were obtained with other cell lines, but there were sufficient differences to indicate that the cell phenotype is, in part, a determinant of the endocytic response to PDT. Further work will be needed to delineate the role of these endocytic effects in the array of responses to photodynamic therapy. PMID:22057481

  8. Treatment of ichthyophthiriasis with photodynamically active chlorophyllin.

    PubMed

    Häder, D-P; Schmidl, J; Hilbig, R; Oberle, M; Wedekind, H; Richter, P R

    2016-04-01

    Water-soluble chlorophyll (chlorophyllin) exerts pronounced photodynamic activity on fish parasites. In order to determine its potential as a remedy against ectoparasites in fish carps were incubated in water with defined concentrations of chlorophyllin. The main focus of the experiments was on the ciliate Ichthyophthirius multifiliis (Fouquet) which is responsible for considerable losses in livestock in aquaculture. As malachite green, which in the past efficiently cured infected fishes, is banned because of its possible carcinogenicity; no effective remedy is presently available in aquaculture to treat ichthyophthiriasis. Using chlorophyllin, the number of trophonts was significantly reduced (more than 50 %) after 3 h incubation of infested fish at 2 and 4 mg/L and subsequent irradiation with simulated solar radiation. The lack of reinfection after light treatment indicates that also the remaining parasites have lost their multiplication capacity. In the controls (no chlorophyllin and no light, light but no chlorophyllin, or chlorophyllin but no light), no reduction of the I. multifiliis infection was observed. We propose that chlorophyllin (or other photodynamic substances) is a possible effective countermeasure against I. multifiliis and other ectoparasites in aquaculture. PMID:26693716

  9. Role of multidrug resistance in photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Diddens, Heyke C.

    1992-06-01

    Multidrug resistance in cancer chemotherapy is a well established phenomenon. One of the most common phenotypical changes in acquired or intrinsic multidrug resistance in human tumor cells is the overexpression of the mdrl gene product P-glycoprotein, which acts as an active efflux pump. Increased levels of P-glycoprotein are associated with resistance to a variety of anticancer drugs commonly used in tumor chemotherapy like anthracyclins, vinca- alcaloids, epipodophyllotoxins or actinomycin D. We investigated the efficacy or photodynamic therapy in the treatment of tumor cells expressing the multidrug resistance phenotype. Our data show that multidrug resistant cells are highly cross resistant to the phototoxic stain rhodamine 123 but exhibit only low degrees of cross resistance (2 - 3 -folds) to the photosensitizers Photosan-3, Clorin-2, methylene blue and meso-tetra (4- sulfonatophenyl) porphine (TPPS4). Resistance is associated with a decrease in intracellular accumulation of the photosensitizer. Verapamil, a membrane active compound known to enhance drug sensitivity in multidrug resistant cells by inhibition of P-glycoprotein, also increases phototoxicity in multidrug resistant cells. Our results imply that tumors expressing the multidrug resistance phenotype might fail to respond to photochemotherapy with rhodamine 123. On the other hand, multidrug resistance may not play an important role in photodynamic therapy with Photosan-3, Chlorin-2, methylene blue or TPPS4.

  10. Photodynamic-induced inactivation of Propionibacterium acnes

    NASA Astrophysics Data System (ADS)

    Koenig, Karsten; Teschke, M.; Eick, Stephen G.; Pfister, W.; Meyer, Herbert; Halbhuber, Karl-Juergen

    1998-05-01

    We report on photodynamically induced inactivation of the skin bacterium Propionibacterium acnes (P. acnes) using endogenous as well as exogenous photosensitizers and red light sources. P. acnes is involved in the pathogenesis of the skin disease acne vulgaris. The skin bacterium is able to synthesize the metal-free fluorescent porphyrins protoporphyrin IX (PP) and coproporphyrin (CP) as shown by in situ spectrally-resolved detection of natural autofluorescence of human skin and bacteria colonies. These naturally occurring intracellular porphyrins act as efficient endogenous photosensitizers. Inactivation of P. acnes suspensions was achieved by irradiation with He-Ne laser light in the red spectral region (632.8 nm). We monitored the photodynamically-induced death of single bacteria using a fluorescent viability kit in combination with confocal laser scanning microscopy. In addition, the photo-induced inactivation was calculated by CFU (colony forming units) determination. We found 633 nm-induced inactivation (60 mW, 0.12 cm2 exposure area, 1 hour irradiation) of 72% in the case of non-incubated bacteria based on the destructive effect of singlet oxygen produced by red light excited endogenous porphyrins and subsequent energy transfer to molecular oxygen. In order to achieve a nearly complete inactivation within one exposure procedure, the exogenous photosensitizer Methylene Blue (Mb) was added. Far red exposure of Mb-labeled bacteria using a krypton ion laser at 647 nm and 676 nm resulted in 99% inactivation.

  11. Photodynamic action of protoporphyrin IX derivatives on Trichophyton rubrum*

    PubMed Central

    Ramos, Rogério Rodrigo; Kozusny-Andreani, Dora Inês; Fernandes, Adjaci Uchôa; Baptista, Mauricio da Silva

    2016-01-01

    BACKGROUND Dermatophytes are filamentous keratinophilic fungi. Trichophyton rubrum is a prevalent infectious agent in tineas and other skin diseases. Drug therapy is considered to be limited in the treatment of such infections, mainly due to low accessibility of the drug to the tissue attacked and development of antifungal resistance in these microorganisms. In this context, Photodynamic Therapy is presented as an alternative. OBJECTIVE Evaluate, in vitro, the photodynamic activity of four derivatives of Protoporphyrin IX by irradiation with LED 400 nm in T. rubrum. METHOD Assays were subjected to irradiation by twelve cycles of ten minutes at five minute intervals. RESULT Photodynamic action appeared as effective with total elimination of UFCs from the second irradiation cycle. CONCLUSION Studies show that the photodynamic activity on Trichophyton rubrum relates to a suitable embodiment of the photosensitizer, which can be maximized by functionalization of peripheral groups of the porphyrinic ring. PMID:27192510

  12. Photodynamic Therapy in Non-Gastrointestinal Thoracic Malignancies.

    PubMed

    Kidane, Biniam; Hirpara, Dhruvin; Yasufuku, Kazuhiro

    2016-01-01

    Photodynamic therapy has a role in the management of early and late thoracic malignancies. It can be used to facilitate minimally-invasive treatment of early endobronchial tumours and also to palliate obstructive and bleeding effects of advanced endobronchial tumours. Photodynamic therapy has been used as a means of downsizing tumours to allow for resection, as well as reducing the extent of resection necessary. It has also been used successfully for minimally-invasive management of local recurrences, which is especially valuable for patients who are not eligible for radiation therapy. Photodynamic therapy has also shown promising results in mesothelioma and pleural-based metastatic disease. As new generation photosensitizers are being developed and tested and methodological issues continue to be addressed, the role of photodynamic therapy in thoracic malignancies continues to evolve. PMID:26805818

  13. Photodynamic Therapy in Non-Gastrointestinal Thoracic Malignancies

    PubMed Central

    Kidane, Biniam; Hirpara, Dhruvin; Yasufuku, Kazuhiro

    2016-01-01

    Photodynamic therapy has a role in the management of early and late thoracic malignancies. It can be used to facilitate minimally-invasive treatment of early endobronchial tumours and also to palliate obstructive and bleeding effects of advanced endobronchial tumours. Photodynamic therapy has been used as a means of downsizing tumours to allow for resection, as well as reducing the extent of resection necessary. It has also been used successfully for minimally-invasive management of local recurrences, which is especially valuable for patients who are not eligible for radiation therapy. Photodynamic therapy has also shown promising results in mesothelioma and pleural-based metastatic disease. As new generation photosensitizers are being developed and tested and methodological issues continue to be addressed, the role of photodynamic therapy in thoracic malignancies continues to evolve. PMID:26805818

  14. Chlorophyll mediated photodynamic inactivation of blue laser on Streptococcus mutans

    NASA Astrophysics Data System (ADS)

    Astuti, Suryani Dyah; Zaidan, A.; Setiawati, Ernie Maduratna; Suhariningsih

    2016-03-01

    Photodynamic inactivation is an inactivation method in microbial pathogens that utilize light and photosensitizer. This study was conducted to investigate photodynamic inactivation effects of low intensity laser exposure with various dose energy on Streptococcus mutans bacteria. The photodynamic inactivation was achieved with the addition of chlorophyll as photosensitizers. To determine the survival percentage of Streptococcus mutans bacteria after laser exposure, the total plate count method was used. For this study, the wavelength of the laser is 405 nm and variables of energy doses are 1.44, 2.87, 4.31, 5.74, 7.18, and 8.61 in J/cm2. The results show that exposure to laser with energy dose of 7.18 J/cm2 has the best photodynamic inactivation with a decrease of 78% in Streptococcus

  15. Ozone-photodynamic effect in the experiment in vitro

    NASA Astrophysics Data System (ADS)

    Loginov, L. E.; Budzinsky, A. A.; Torshina, Nadezgda L.; Posypanova, Anna M.; Volkova, Anna I.

    1996-12-01

    With the purpose of increased photodestruction oncocells we develop a method of ozone-photodynamic therapy. As a target cell for laser processing we are using photosensibilitable erythrocytes of integral blood patient, past seance of ozonetherapy.

  16. Inhibiton of photodynamic haemolysis by Gratiola officinalis L. extract

    NASA Astrophysics Data System (ADS)

    Tkachenko, Natalie; Pravdin, Alexander; Terentyuk, George; Navolokin, Nikita; Kurchatova, Maria; Polukonova, Natalia

    2015-03-01

    On the model of photodynamic haemolysis, the membranoprotective properties of a plant origin antioxidant, Gratiola officinalis L. extract, have been studied based on its ability to inhibit photodamage of sensitized erythrocyte membranes. The effect of different concentrations of the antioxidant on the photodynamic hemolysis has been studied; and the influence of incubation time on the membranoprotective properties of Gratiola officinalis L. extract has also been revealed.

  17. Photodynamic/photocatalytic effects on microorganisms processed by nanodyes

    NASA Astrophysics Data System (ADS)

    Tuchina, Elena S.; Tuchin, Valery V.

    2010-02-01

    Photodynamic therapy uses laser, LED or lamp light sources in combination with dyes - exogenous photosensitizers for the enhancement and localization of photodynamic effects within the human body. We are developing a new approach of improvement of the efficiency of antimicrobial phototherapy via combined application of photosensitizers and the photocatalysts to pathogenic microorganisms. The main goal of the paper is to conduct experiments to study the action of nanodyes, based on mixtures of nanoparticles and photosensitizers, in combination with LED irradiation of pathogens.

  18. Oxidative stress of photodynamic antimicrobial chemotherapy inhibits Candida albicans virulence

    NASA Astrophysics Data System (ADS)

    Kato, Ilka Tiemy; Prates, Renato Araujo; Tegos, George P.; Hamblin, Michael R.; Simões Ribeiro, Martha

    2011-03-01

    Photodynamic antimicrobial chemotherapy (PACT) is based on the principal that microorganisms will be inactivated using a light source combined to a photosensitizing agent in the presence of oxygen. Oxidative damage of cell components occurs by the action of reactive oxygen species leading to cell death for microbial species. It has been demonstrated that PACT is highly efficient in vitro against a wide range of pathogens, however, there is limited information for its in vivo potential. In addition, it has been demonstrated that sublethal photodynamic inactivation may alter the virulence determinants of microorganisms. In this study, we explored the effect of sublethal photodynamic inactivation to the virulence factors of Candida albicans. Methylene Blue (MB) was used as photosensitizer for sublethal photodynamic challenge on C. albicans associated with a diode laser irradiation (λ=660nm). The parameters of irradiation were selected in causing no reduction of viable cells. The potential effects of PACT on virulence determinants of C. albicans cells were investigated by analysis of germ tube formation and in vivo pathogenicity assays. Systemic infection was induced in mice by the injection of fungal suspension in the lateral caudal vein. C. albicans exposed to sublethal photodynamic inactivation formed significantly less germ tube than untreated cells. In addition, mice infected with C. albicans submitted to sublethal PACT survived for a longer period of time than mice infected with untreated cells. The oxidative damage promoted by sublethal photodynamic inactivation inhibited virulence determinants and reduced in vivo pathogenicity of C. albicans.

  19. Photodynamic Cancer Therapy—Recent Advances

    NASA Astrophysics Data System (ADS)

    Abrahamse, Heidi

    2011-09-01

    The basic principle of the photodynamic effect was discovered over a hundred years ago leading to the pioneering work on PDT in Europe. It was only during the 1980s, however, when "photoradiation therapy" was investigated as a possible treatment modality for cancer. Photodynamic therapy (PDT) is a photochemotherapeutic process which requires the use of a photosensitizer (PS) that, upon entry into a cancer cell is targeted by laser irradiation to initiate a series of events that contribute to cell death. PSs are light-sensitive dyes activated by a light source at a specific wavelength and can be classified as first or second generation PSs based on its origin and synthetic pathway. The principle of PS activation lies in a photochemical reaction resulting from excitation of the PS producing singlet oxygen which in turn reacts and damages cell organelles and biomolecules required for cell function and ultimately leading to cell destruction. Several first and second generation PSs have been studied in several different cancer types in the quest to optimize treatment. PSs including haematoporphyrin derivative (HpD), aminolevulinic acid (ALA), chlorins, bacteriochlorins, phthalocyanines, naphthalocyanines, pheophorbiedes and purpurins all require selective uptake and retention by cancer cells prior to activation by a light source and subsequent cell death induction. Photodynamic diagnosis (PDD) is based on the fluorescence effect exhibited by PSs upon irradiation and is often used concurrently with PDT to detect and locate tumours. Both laser and light emitting diodes (LED) have been used for PDT depending on the location of the tumour. Internal cancers more often require the use of laser light delivery using fibre optics as delivery system while external PDT often make use of LEDs. Normal cells have a lower uptake of the PS in comparison to tumour cells, however the acute cytotoxic effect of the compound on the recovery rate of normal cells is not known. Subcellular

  20. A Comprehensive Tutorial on In Vitro Characterization of New Photosensitizers for Photodynamic Antitumor Therapy and Photodynamic Inactivation of Microorganisms

    PubMed Central

    Maisch, Tim; Berneburg, Mark; Plaetzer, Kristjan

    2013-01-01

    In vitro research performed on eukaryotic or prokaryotic cell cultures usually represents the initial step for characterization of a novel photosensitizer (PS) intended for application in photodynamic therapy (PDT) of cancer or photodynamic inactivation (PDI) of microorganisms. Although many experimental steps of PS testing make use of the wide spectrum of methods readily employed in cell biology, special aspects of working with photoactive substances, such as the autofluorescence of the PS molecule or the requirement of light protection, need to be considered when performing in vitro experiments in PDT/PDI. This tutorial represents a comprehensive collection of operative instructions, by which, based on photochemical and photophysical properties of a PS, its uptake into cells, the intracellular localization and photodynamic action in both tumor cells and microorganisms novel photoactive molecules may be characterized for their suitability for PDT/PDI. Furthermore, it shall stimulate the efforts to expand the convincing benefits of photodynamic therapy and photodynamic inactivation within both established and new fields of applications and motivate scientists of all disciplines to get involved in photodynamic research. PMID:23762860

  1. Irradiation system for interstitial photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Pacheco, L.; Stolik, S.; De la Rosa, J.

    2013-11-01

    Interstitial Photodynamic Therapy (IPDT) is a promising form of treatment of deep-seated and bulky malignant tumors, based on the lethal cell response to the photochemical reactions when drug is light activated in presence of oxygen. In order to accomplish an effective internal illumination, laser sources are preferably used because of two important reasons: the monochromatic light can be confined to the narrow absorption band of the drug and the laser beam is easily focused into optical fibers. In this work the development of a diode-laser-light-source is presented. The system is tuned by temperature to get a better match in the 5-ALA absorption band. This system also comprises a trifurcated fiber system to accomplish interstitial illumination.

  2. Mechanism of photodynamic activity of pheophorbides

    NASA Astrophysics Data System (ADS)

    Tanielian, Charles; Kobayashi, Masami; Wolff, Christian

    2001-04-01

    Plasmid DNA is efficiently photocleaved by sodium pheophorbides (Na-Phdes) a and b in the absence of oxygen as well as in the presence of oxygen. Fluorescence microscopic observation shows a rapid incorporation of Na-Phde a into nuclei, mitochondria, and lysosome of human oral mucosa cells. In contrast Na-Phde b is incorporated only into the plasma membrane. The photodynamic activity of these pigments in living tissues is probably determined by the monomeric pigment molecules formed in hydrophobic cellular structures and involves two types of reactions: (1) direct electron transfer between DNA bases (especially guanine) and pheophorbide singlet excited state, and (2) indirect reactions medicated by reactive oxygen species, including singlet oxygen whose production from molecular oxygen is sensitized by the Na-Phdes triplet state.

  3. PHOTODYNAMIC THERAPY OF CANCER: AN UPDATE

    PubMed Central

    Agostinis, Patrizia; Berg, Kristian; Cengel, Keith A.; Foster, Thomas H.; Girotti, Albert W.; Gollnick, Sandra O.; Hahn, Stephen M.; Hamblin, Michael R.; Juzeniene, Asta; Kessel, David; Korbelik, Mladen; Moan, Johan; Mroz, Pawel; Nowis, Dominika; Piette, Jacques; Wilson, Brian C.; Golab, Jakub

    2011-01-01

    Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic procedure that can exert a selective cytotoxic activity toward malignant cells. The procedure involves administration of a photosensitizing agent followed by irradiation at a wavelength corresponding to an absorbance band of the sensitizer. In the presence of oxygen, a series of events lead to direct tumor cell death, damage to the microvasculature and induction of a local inflammatory reaction. Clinical studies revealed that PDT can be curative particularly in early-stage tumors. It can prolong survival in inoperable cancers and significantly improve quality of life. Minimal normal tissue toxicity, negligible systemic effects, greatly reduced long-term morbidity, lack of intrinsic or acquired resistance mechanisms, and excellent cosmetic as well as organ function-sparing effects of this treatment make it a valuable therapeutic option for combination treatments. With a number of recent technological improvements, PDT has the potential to become integrated into the mainstream of cancer treatment. PMID:21617154

  4. Photodynamic therapy as an antifungal treatment

    PubMed Central

    LIANG, YI; LU, LI-MING; CHEN, YONG; LIN, YOU-KUN

    2016-01-01

    Photodynamic therapy (PDT) involves the systemic or topical application of a photosensitizer (PS), alongside the selective illumination of the target lesion with light of an appropriate wavelength, in order to promote localized oxidative photodamage and subsequent cell death. Numerous studies have demonstrated that PDT is highly effective in the destruction of fungi in vitro. The mechanism underlying the effects of PDT results from the photons of visible light of an appropriate wavelength interacting with the intracellular molecules of the PS. Reactive species are produced as a result of the oxidative stress caused by the interaction between the visible light and the biological tissue. At present, no antifungal treatment based on PDT has been licensed. However, antifungal PDT is emerging as an area of interest for research. PMID:27347012

  5. Scope of photodynamic therapy in periodontics.

    PubMed

    Kumar, Vivek; Sinha, Jolly; Verma, Neelu; Nayan, Kamal; Saimbi, C S; Tripathi, Amitandra K

    2015-01-01

    Periodontal disease results from inflammation of the supporting structure of the teeth and in response to chronic infection caused by various periodontopathic bacteria. The mechanical removal of this biofilm and adjunctive use of antibacterial disinfectants and antibiotics have been the conventional methods of periodontal therapy. However, the removal of plaque and the reduction in the number of infectious organisms can be impaired in sites with difficult access. Photodynamic therapy (PDT) is a powerful laser-initiated photochemical reaction, involving the use of a photoactive dye (photosensitizer) activated by light of a specific wavelength in the presence of oxygen. Application of PDT in periodontics such as pocket debridement, gingivitis, and aggressive periodontitis continue to evolve into a mature clinical treatment modality and is considered as a promising novel approach for eradicating pathogenic bacteria in periodontitis. PMID:26481895

  6. Monitoring photodynamic therapy with photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Shao, Peng; Chapman, David W.; Moore, Ronald B.; Zemp, Roger J.

    2015-10-01

    We present our work on examining the feasibility of monitoring photodynamic therapy (PDT)-induced vasculature change with acoustic-resolution photoacoustic microscopy (PAM). Verteporfin, an FDA-approved photosensitizer for clinical PDT, was utilized. With a 60-μm-resolution PAM system, we demonstrated the capability of PAM to monitor PDT-induced vasculature variations in a chick chorioallantoic membrane model with topical application and in a rat ear with intravenous injection of the photosensitizer. We also showed oxygen saturation change in target blood vessels due to PDT. Success of the present approach may potentially lead to the application of PAM imaging in evaluating PDT efficacy, guiding treatment, and predicting responders from nonresponders.

  7. Death pathways associated with photodynamic therapy

    PubMed Central

    Kessel, David

    2009-01-01

    When the mitochondria and/or the endoplasmic reticulum were targeted by photodynamic therapy, photodamage to the anti-apoptotic protein Bcl-2 was observed. This led to an apoptotic outcome if that death pathway was available. Lysosomal photodamage ultimately resulted in activation of the pro-apoptotic protein Bid, also leading to apoptosis. Photodamage to the plasma membrane was associated with migration of sensitizers to the cytosol and procaspase photodamage, with apoptosis impaired. Where apoptosis was unavailable because of lack of necessary components of the program, an autophagic outcome has been observed. It is also clear that autophagy can occur along with apoptosis as a PDT response, and may play a role in immunologic responses to photodamaged tumor cells. PMID:19890442

  8. Initiation of Autophagy by Photodynamic Therapy

    PubMed Central

    Kessel, David; Oleinick, Nancy L.

    2010-01-01

    Photodynamic therapy (PDT) involves the irradiation of photosensitized cells with light. Depending on localization of the photosensitizing agent, the process can induce photodamage to the endoplasmic reticulum (ER), mitochondria, plasma membrane, and/or lysosomes. When ER or mitochondria are targeted, antiapoptotic proteins of the Bcl-2 family are especially sensitive to photodamage. Both apoptosis and autophagy can occur after PDT, autophagy being associated with enhanced survival at low levels of photodamage to some cells. Autophagy can become a cell-death pathway if apoptosis is inhibited or when cells attempt to recycle damaged constituents beyond their capacity for recovery. While techniques associated with characterization of autophagy are generally applicable, PDT introduces additional factors related to unknown sites of photodamage that may alter autophagic pathways. This chapter discusses issues that may arise in assessing autophagy after cellular photodamage. PMID:19216899

  9. Dosimetry for photodynamic therapy of endometrial tissue

    NASA Astrophysics Data System (ADS)

    Svaasand, Lars O.; Fehr, Mathias K.; Madsen, Sten; Tadir, Yona; Tromberg, Bruce J.

    1995-05-01

    Hysterectomy is the most common major operation performed in the United States with dysfunctional uterine bleeding as one of the major indications. The clinical needs for simple and safe endometrial destruction are essential. Photodynamic therapy (PDT) may offer a simple and cost effective solution for the treatment of dysfunctional uterine bleeding. The dosimetry is discussed for the case of topical application of photosensitizer. This technique might be the method of preference because undesired side effects such as skin photosensitization that is typical for systemically injected photosensitizers, can be avoided. Effective PDT requires a sufficient amount of light delivered to the targeted tissue in a reasonable period of time. A trifurcated optical applicator consisting of three cylindrical diffusing fibers has been constructed, and this applicator can deliver a typical required optical dose of about 50-100 J/cm2 to the full depth of the endometrium for an exposure time of 10-20 minutes.

  10. Progress of Photodynamic Therapy in Gastric Cancer

    PubMed Central

    Narahara, Hiroyuki; Otani, Toru; Okuda, Shigeru

    1999-01-01

    Progress of photodynamic therapy (PDT) in gastric cancer and the clinical outcome are described in this paper. (1) We included the whole lesion and a 5 mm margin in the field for irradiation. Marking by injection of India-ink showing the irradiation field was performed beforehand. (2) We established the standard light dose to be 90 J/cm2 for an argon dye laser and 60 J/cm2 for a pulse wave laser. (3) The size of cancerous lesion curable by PDT was expanded from 3 cm in diameter, i.e. 7 cm2 in area to 4 cm in diameter, i.e. 13 cm2 by employing a new excimer dye laser model, which could emit 4mJ/pulse with 80 Hz pulse frequency. (4) The depth of cancer invasion which could be treated by PDT was increased from about 4 mm, i.e. the superficial part of the submucosal layer (SM-1) to more than 10 mm in depth, i.e. the proper muscular layer. These improvements owe much to the pulse laser, the photodynamic action induced by which permits deeper penetration than that of a continuous wave laser. (5) We employed a side-viewing fiberscope for gastric PDT to irradiate the lesion from an angle of 90°. (6) We designed a simple cut quartz fiber for photoradiation with a spiral spring thickened toward the end. (7) We developed an endoscopic device for photoradiation in PDT which achieves accurate and efficient irradiation. As a result of these improvements a higher cure rate was obtained even with a lower light dose of irradiation. PMID:18493500

  11. Somatostatin Analogues for Receptor Targeted Photodynamic Therapy

    PubMed Central

    Kaščáková, Slávka; Hofland, Leo J.; De Bruijn, Henriette S.; Ye, Yunpeng; Achilefu, Samuel; van der Wansem, Katy; van der Ploeg-van den Heuvel, Angelique; van Koetsveld, Peter M.; Brugts, Michael P.; van der Lelij, Aart-Jan; Sterenborg, Henricus J. C. M.; ten Hagen, Timo L. M.; Robinson, Dominic J.; van Hagen, Martin P.

    2014-01-01

    Photodynamic therapy (PDT) is an established treatment modality, used mainly for anticancer therapy that relies on the interaction of photosensitizer, light and oxygen. For the treatment of pathologies in certain anatomical sites, improved targeting of the photosensitizer is necessary to prevent damage to healthy tissue. We report on a novel dual approach of targeted PDT (vascular and cellular targeting) utilizing the expression of neuropeptide somatostatin receptor (sst2) on tumor and neovascular-endothelial cells. We synthesized two conjugates containing the somatostatin analogue [Tyr3]-octreotate and Chlorin e6 (Ce6): Ce6-K3-[Tyr3]-octreotate (1) and Ce6-[Tyr3]-octreotate-K3-[Tyr3]-octreotate (2). Investigation of the uptake and photodynamic activity of conjugates in-vitro in human erythroleukemic K562 cells showed that conjugation of [Tyr3]-octreotate with Ce6 in conjugate 1 enhances uptake (by a factor 2) in cells over-expressing sst2 compared to wild-type cells. Co-treatment with excess free Octreotide abrogated the phototoxicity of conjugate 1 indicative of a specific sst2-mediated effect. In contrast conjugate 2 showed no receptor-mediated effect due to its high hydrophobicity. When compared with un-conjugated Ce6, the PDT activity of conjugate 1 was lower. However, it showed higher photostability which may compensate for its lower phototoxicity. Intra-vital fluorescence pharmacokinetic studies of conjugate 1 in rat skin-fold observation chambers transplanted with sst2+ AR42J acinar pancreas tumors showed significantly different uptake profiles compared to free Ce6. Co-treatment with free Octreotide significantly reduced conjugate uptake in tumor tissue (by a factor 4) as well as in the chamber neo-vasculature. These results show that conjugate 1 might have potential as an in-vivo sst2 targeting photosensitizer conjugate. PMID:25111655

  12. Therapeutic and Aesthetic Uses of Photodynamic Therapy Part five of a five-part series

    PubMed Central

    2009-01-01

    The use of 5-aminolevulinic acid–photodynamic therapy in clinical practice is an individual determination based on experiences learned from clinicians and from personal experience. This manuscript reviews how one clinician approaches patients interested in having photodynamic therapy. It covers all practical aspects of the treatment process and reviews how photodynamic therapy can be utilized in your clinical practice. PMID:20967186

  13. Quantum Cryptography II: How to re-use a one-time pad safely even if P=NP.

    PubMed

    Bennett, Charles H; Brassard, Gilles; Breidbart, Seth

    2014-01-01

    When elementary quantum systems, such as polarized photons, are used to transmit digital information, the uncertainty principle gives rise to novel cryptographic phenomena unachievable with traditional transmission media, e.g. a communications channel on which it is impossible in principle to eavesdrop without a high probability of being detected. With such a channel, a one-time pad can safely be reused many times as long as no eavesdrop is detected, and, planning ahead, part of the capacity of these uncompromised transmissions can be used to send fresh random bits with which to replace the one-time pad when an eavesdrop finally is detected. Unlike other schemes for stretching a one-time pad, this scheme does not depend on complexity-theoretic assumptions such as the difficulty of factoring. PMID:25400534

  14. 75 FR 9997 - Bureau of Educational and Cultural Affairs (ECA) Request for Grant Proposals (RFGP): One-time...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... Grants Program-- Competition A--Academic Programs Announcement Type: New Grant Funding Opportunity Number... Program'' is $8 million. Four million dollars will be dedicated to Competition A--Academic Programs One... The Office of Academic Programs will accept proposals for the following one-time special...

  15. Mitochondria-targeting for improved photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Ngen, Ethel J.

    Photodynamic therapy (PDT) is an emerging cancer therapeutic modality, with great potential to selectively treat surface cancers, thus minimizing systemic side effects. In this dissertation, two approaches to deliver photosensitizers to mitochondria were investigated: 1) Reducing photosensitizer sizes to improve endocytosis and lysosomal localization. Upon irradiation the photosensitizers would then produce singlet oxygen which could rupture the lysosomal membrane releasing the lysosomally trapped photosensitizers to the cytosol, from where they could relocalize to mitochondria by passive diffusion (photochemical internalization). 2) Using delocalized lipophilic cationic dyes (DLCs) to exploit membrane potential differences between the cytoplasm and mitochondria in delivering photosensitizers to mitochondria. To investigate the effects of steric hindrance on mitochondrial localization and photodynamic response, a series of eight thiaporphyrins were studied. Two new thiaporphyrin analogues 6 and 8 with reduced steric hindrance at the 10- and 15- meso positions were studied in comparison to 5,20-diphenyl-10,15-bis[4 (carboxymethyleneoxy)-phenyl]-21,23-dithiaporphyrin 1, previously validated as a potential second generation photosensitizer. Although 6 showed an extraordinarily high uptake (7.6 times higher than 1), it was less potent than 1 (IC 50 = 0.18 muM versus 0.13 muM) even though they both showed similar sub-cellular localization patterns. This low potency was attributed to its high aggregation tendency in aqueous media (4 times higher than 1), which might have affected its ability to generate singlet oxygen in vitro . 8 on the other hand showed an even lower potency than 6 (2.28 vs 0.18 muM). However this was attributed to its low cellular uptake (20 times less than 6) and inefficient generation of singlet oxygen. Overall, although the structural modifications did improve the cellular uptake of 6, 6 was still less potent than the lead photosensitizers 1. Thus

  16. Graphene-based nanovehicles for photodynamic medical therapy

    PubMed Central

    Li, Yan; Dong, Haiqing; Li, Yongyong; Shi, Donglu

    2015-01-01

    Graphene and its derivatives such as graphene oxide (GO) have been widely explored as promising drug delivery vehicles for improved cancer treatment. In this review, we focus on their applications in photodynamic therapy. The large specific surface area of GO facilitates efficient loading of the photosensitizers and biological molecules via various surface functional groups. By incorporation of targeting ligands or activatable agents responsive to specific biological stimulations, smart nanovehicles are established, enabling tumor-triggering release or tumor-selective accumulation of photosensitizer for effective therapy with minimum side effects. Graphene-based nanosystems have been shown to improve the stability, bioavailability, and photodynamic efficiency of organic photosensitizer molecules. They have also been shown to behave as electron sinks for enhanced visible-light photodynamic activities. Owing to its intrinsic near infrared absorption properties, GO can be designed to combine both photodynamic and photothermal hyperthermia for optimum therapeutic efficiency. Critical issues and future aspects of photodynamic therapy research are addressed in this review. PMID:25848263

  17. Graphene-based nanovehicles for photodynamic medical therapy.

    PubMed

    Li, Yan; Dong, Haiqing; Li, Yongyong; Shi, Donglu

    2015-01-01

    Graphene and its derivatives such as graphene oxide (GO) have been widely explored as promising drug delivery vehicles for improved cancer treatment. In this review, we focus on their applications in photodynamic therapy. The large specific surface area of GO facilitates efficient loading of the photosensitizers and biological molecules via various surface functional groups. By incorporation of targeting ligands or activatable agents responsive to specific biological stimulations, smart nanovehicles are established, enabling tumor-triggering release or tumor-selective accumulation of photosensitizer for effective therapy with minimum side effects. Graphene-based nanosystems have been shown to improve the stability, bioavailability, and photodynamic efficiency of organic photosensitizer molecules. They have also been shown to behave as electron sinks for enhanced visible-light photodynamic activities. Owing to its intrinsic near infrared absorption properties, GO can be designed to combine both photodynamic and photothermal hyperthermia for optimum therapeutic efficiency. Critical issues and future aspects of photodynamic therapy research are addressed in this review. PMID:25848263

  18. Photodynamic therapy: Biophysical mechanisms and molecular responses

    NASA Astrophysics Data System (ADS)

    Mitra, Soumya

    In photodynamic therapy (PDT), photochemical reactions induced by optical activation of sensitizer molecules cause destruction of the target tissue. In this thesis we present results of several related studies, which investigated the influence of photophysical properties and photobleaching mechanisms of sensitizers and oxygen-dependent tissue optical properties on PDT treatment efficacy. The bleaching mechanism of the sensitizer meso-tetra hydroxyphenyl chlorin (mTHPC) is examined indirectly using measurements of photochemical oxygen consumption during PDT irradiation of multicell tumor spheroids. Analysis of the results with a theoretical model of oxygen diffusion that incorporates the effects of sensitizer photobleaching shows that mTHPC is degraded via a singlet-oxygen (1O2)-mediated bleaching process. The analysis allows us to extract photophysical parameters of mTHPC which are used to account for its enhanced clinical photodynamic potency in comparison to that of Photofrin. Evaluation of the spatially-resolved fluorescence in confocal optical sections of intact spheroids during PDT irradiation allows for the direct experimental verification of mTHPC's 1O2-mediated bleaching mechanism. The technique is also used to investigate the complex bleaching kinetics of Photofrin. The results allow us to successfully reconcile apparently contradictory experimental observations and to confirm the predictions of a new theoretical model in which both 1O2 and excited triplet sensitizer molecules are allowed to contribute to photobleaching. Based on studies performed in tissue-simulating erythrocyte phantoms and in a murine tumor model in vivo, we present clinically relevant results which indicate that a shift toward increased hemoglobin-oxygen saturation due to improved tissue oxygenation reduces PDT treatment beam attenuation and may allow for more effective treatment of deeper lesions. Finally, we investigate the induction of the stress protein, heat shock protein 70 (HSP

  19. Photodynamic therapy for treatment of head and neck cancer.

    PubMed

    Schweitzer, V G

    1990-03-01

    Since 1975, photodynamic therapy has reportedly been effective in a variety of head and neck malignancies that failed traditional (conventional) therapy, including surgery, cryotherapy, chemotherapy, hyperthermia, and radiation therapy. Photodynamic therapy consists of the intravenous administration of (di)hematoporphyrin ether, a chemosensitizing drug selectively retained by neoplastic and reticuloendothelial tissues which, when exposed to a 630-nm argon laser, catalyzes a photochemical reaction to release free oxygen radicals, "the cytotoxic" agents responsible for cell death and tumor necrosis. Preliminary investigations have assessed the efficacy of photodynamic therapy in treatment of: (1) superficial "condemned mucosa" or "field cancerization" of the oral cavity and (2) stage III and IV head and neck carcinomas that had unsuccessful conventional therapy. Complete and/or partial remissions were obtained in 11 of 12 patients (16 treatments) with a variety of carcinomas of the nasopharynx, palate and uvula, retromolar trigone, temporal bone, cervical esophagus, and AIDS-related Kaposi's sarcoma of the oral cavity. PMID:2108409

  20. Nitrosylhemoglobin in photodynamically stressed human tumors growing in nude mice.

    PubMed

    Jakubowska, Monika; Michalczyk-Wetula, Dominika; Pyka, Janusz; Susz, Anna; Urbanska, Krystyna; Płonka, Beata K; Kuleta, Patryk; Łącki, Piotr; Krzykawska-Serda, Martyna; Fiedor, Leszek; Płonka, Przemysław M

    2013-11-30

    The role of nitric oxide in human tumor biology and therapy has been the subject of extensive studies. However, there is only limited knowledge about the mechanisms of NO production and its metabolism, and about the role NO can play in modern therapeutic procedures, such as photodynamic therapy. Here, for the first time, we report the presence of nitrosylhemoglobin, a stable complex of NO, in human lung adenocarcinoma A549 tumors growing in situ in nude mice. Using electron paramagnetic resonance spectroscopy we show that the level of nitrosylhemoglobin increases in the course of photodynamic therapy and that the phenomenon is local. Even the destruction of strongly vascularized normal liver tissue did not induce the paramagnetic signal, despite bringing about tissue necrosis. We conclude that photodynamic stress substantiates NO production and blood extravasation in situ, both processes on-going even in non-treated tumors, although at a lower intensity. PMID:23973529

  1. Optical delivery and monitoring of photodynamic therapy of prostate cancer

    NASA Astrophysics Data System (ADS)

    Weersink, Robert A.; Bogaards, Arjun; Gertner, Mark; Davidson, Sean; Zhang, Kai; Netchev, George; Giewercer, David J.; Trachtenberg, John; Wilson, Brian C.

    2004-10-01

    Photodynamic therapy of recurrent prostate cancer is currently undergoing Phase II clinical trials with the vascular targeting drug TOOKAD. Proper PDT dosage requires sound estimates of the light fluence and drug concentration throughout the organ. The treatment requires multiple diffusing light delivery fibers placed in position according to a light dose treatment plan under ultrasound guidance. Fluence rate is monitored by multiple sensor fibers placed throughout the organ and in sensitive organs near the prostate. The combination of multiple light delivery and fluence sensor fibers is used to estimate the optical properties of the tissue and to provide a general fluence map throughout the organ. This fluence map is then used to estimate extent of photodynamic dose. Optical spectroscopy is used to monitor drug pharmacokinetics in the organ and blood hemodynamics within the organ. Further development of these delivery and monitoring techniques will permit full online monitoring of the treatment that will enable real-time patient-specific delivery of photodynamic therapy.

  2. Effects of Methane-Rich Saline on the Capability of One-Time Exhaustive Exercise in Male SD Rats

    PubMed Central

    Xin, Lei; Sun, Xuejun; Lou, Shujie

    2016-01-01

    Purpose To explore the effects of methane-rich saline (CH4 saline) on the capability of one-time exhaustive exercise in male SD rats. Methods Thirty rats were equally divided into to three groups at random: control group (C), placebo group (P) and methane saline group (M). Rats in M group underwent intraperitoneal injection of CH4 saline, and the other two groups simultaneously underwent intraperitoneal injection of normal saline. Then, the exercise capability of rats was tested through one-time exhaustive treadmill exercise except C group. Exercise time and body weight were recorded before and after one-time exhaustive exercise. After exhaustive exercise, the blood and gastrocnemius samples were collected from all rats to detect biochemical parameters in different methods. Results It was found that the treadmill running time was significantly longer in rats treated with CH4 saline. At the same time, CH4 saline reduced the elevation of LD and UN in blood caused by one-time exhaustive exercise. The low level of blood glucose induced by exhaustive exercise was also normalized by CH4 saline. Also CH4 saline lowered the level of CK in plasma. Furthermore, this research indicated that CH4 saline markedly increased the volume of T-AOC in plasma and alleviated the peak of TNF-α in both plasma and gastrocnemius. From H&E staining, CH4 saline effectively improved exercise-induced structural damage in gastrocnemius. Conclusions CH4 saline could enhance exercise capacity in male SD rats through increase of glucose aerobic oxidation, improvement of metabolic clearance and decrease of exhaustive exercise-induced gastrocnemius injury. PMID:26942576

  3. Photodynamic therapy on normal rabbit mandible

    NASA Astrophysics Data System (ADS)

    Fan, Kathleen F.; Hopper, Colin; Speight, Paul M.; Davies, Claire; Bown, Stephen G.

    1995-03-01

    Photodynamic therapy has been proposed as an intra-operative adjunct to surgical resection of tumors invading bone. To assess this, we studied the effects of PDT in normal bone. Forty- four rabbits were sensitized with Photofrin 3 mg/kg, 5-aminolaevulinic acid (ALA) 400 mg/kg, or meso-tetrahydroxyphenylchlorin (mTHPC) 0.3 mg/kg. A mandibular incisor was removed and the socket irradiated with a cylindrical diffusion fiber (630 nm Photofrin and ALA, 650 nm mTHPC, 100 J per treatment). Irradiation was given 1 or 48 hours after Photofrin, 72 hours after mTHPC, whilst 2 doses were given 2.5 and 4 hours after the first fractionated dose of ALA. The socket of the ipsilateral maxillary incisor was used as a nonirradiated control to assess healing without PDT. Other controls assessed healing after irradiation of unsensitized animals. Rabbits were killed 3, 10, and 21 days after treatment. Tooth socket healing appeared to be the same in all groups of animals with evidence of woven bone formation by 10 days. We conclude that PDT is unlikely to have any effect on healing in normal bone, which makes it suitable for treating tumors invading bone.

  4. Melanoma resistance to photodynamic therapy: new insights

    PubMed Central

    Huang, Ying-Ying; Vecchio, Daniela; Avci, Pinar; Yin, Rui; Garcia-Diaz, Maria; Hamblin, Michael R.

    2012-01-01

    Melanoma is the most dangerous form of skin cancer, with a steeply rising incidence and a poor prognosis in its advanced stages. Melanoma is highly resistant to traditional chemotherapy and radiotherapy, although modern targeted therapies such as BRAF inhibitors are showing some promise. Photodynamic therapy (PDT, the combination of photosensitizing dyes and visible light) has been tested for melanoma with some promising results, but melanoma is generally considered to also be resistant to PDT. Optical interference by the highly-pigmented melanin, the anti-oxidant effect of melanin, the sequestration of photosensitizers inside melanosomes, defects in apoptotic pathways, and the efflux of photosensitizers by ATP-binding cassette (ABC) transporters have all been implicated in melanoma resistance to PDT. Approaches to overcoming melanoma resistance to PDT include: the discovery of highly active photosensitizers absorbing in the 700–800-nm near infrared spectral region; interventions that can temporarily reduce the amount or the pigmentation of the melanin; compounds that can reverse apoptotic defects or inhibit drug-efflux of photosensitizers; and immunotherapy approaches that can take advantage of the ability of PDT to activate the host immune system to the treated tumor. PMID:23152406

  5. Photodynamic antibacterial effect of graphene quantum dots.

    PubMed

    Ristic, Biljana Z; Milenkovic, Marina M; Dakic, Ivana R; Todorovic-Markovic, Biljana M; Milosavljevic, Momir S; Budimir, Milica D; Paunovic, Verica G; Dramicanin, Miroslav D; Markovic, Zoran M; Trajkovic, Vladimir S

    2014-05-01

    Synthesis of new antibacterial agents is becoming increasingly important in light of the emerging antibiotic resistance. In the present study we report that electrochemically produced graphene quantum dots (GQD), a new class of carbon nanoparticles, generate reactive oxygen species when photoexcited (470 nm, 1 W), and kill two strains of pathogenic bacteria, methicillin-resistant Staphylococcus aureus and Escherichia coli. Bacterial killing was demonstrated by the reduction in number of bacterial colonies in a standard plate count method, the increase in propidium iodide uptake confirming the cell membrane damage, as well as by morphological defects visualized by atomic force microscopy. The induction of oxidative stress in bacteria exposed to photoexcited GQD was confirmed by staining with a redox-sensitive fluorochrome dihydrorhodamine 123. Neither GQD nor light exposure alone were able to cause oxidative stress and reduce the viability of bacteria. Importantly, mouse spleen cells were markedly less sensitive in the same experimental conditions, thus indicating a fairly selective antibacterial photodynamic action of GQD. PMID:24612819

  6. Progress in photodynamic therapy on tumors

    NASA Astrophysics Data System (ADS)

    Tian, Y. Y.; Wang, L. L.; Wang, W.

    2008-10-01

    Photodynamic therapy (PDT) is a promising treatment on neoplastic pathologic tissues, which involves the administration of a photosensitizing agent followed by the exposure of the tissue to visible nonthermal light. Light energy is captured and transferred to other molecules resulting in the formation of short-lived energetic species, which interact with biological systems and then produce tissue damage. Photosensitizer can be taken up selectively by tumor cells because of the upregulation of low-density lipoprotein receptor-mediated endocytosis and the acidic tumor environments. In recent years, the application of PDT in the treatment of malignant lesions has increased dramatically. The first health agency approval for PDT was granted for Photofrin in Canada in 1993, and, now, it is licensed in many countries for the treatment of cancers. Although Photofrin is the most commonly used photosensitizer, it has significant side effects. Therefore, major effort has been invested in the development of new sensitizers and, to this end, many photosensitizers have been described and some are now in clinical trials.

  7. Light emitting fabric technologies for photodynamic therapy.

    PubMed

    Mordon, Serge; Cochrane, Cédric; Tylcz, Jean Baptiste; Betrouni, Nacim; Mortier, Laurent; Koncar, Vladan

    2015-03-01

    Photodynamic therapy (PDT) is considered to be a promising method for treating various types of cancer. A homogeneous and reproducible illumination during clinical PDT plays a determinant role in preventing under- or over-treatment. The development of flexible light sources would considerably improve the homogeneity of light delivery. The integration of optical fiber into flexible structures could offer an interesting alternative. This paper aims to describe different methods proposed to develop Side Emitting Optical Fibers (SEOF), and how these SEOF can be integrated in a flexible structure to improve light illumination of the skin during PDT. Four main techniques can be described: (i) light blanket integrating side-glowing optical fibers, (ii) light emitting panel composed of SEOF obtained by micro-perforations of the cladding, (iii) embroidery-based light emitting fabric, and (iv) woven-based light emitting fabric. Woven-based light emitting fabrics give the best performances: higher fluence rate, best homogeneity of light delivery, good flexibility. PMID:25481663

  8. The use of photodynamic therapy in dermatology.

    PubMed

    Babilas, P; Szeimies, R M

    2010-10-01

    In dermatology, topical photodynamic therapy (PDT) is a well established treatment modality which has mainly shown to be effective for dermato-oncologic conditions like actinic keratosis, Bowen's disease, in-situ squamous cell carcinoma and superficial basal cell carcinoma. However, a therapeutical benefit of PDT is also evident for inflammatory dermatoses like localized scleroderma, acne vulgaris and granuloma annulare as well as for aesthetic indications like photo aged skin or sebaceous gland hyperplasia. Recent work has been focused on the development and evaluation of topical photosensitizers like the hem precursor 5-aminolevulinic acid or its methyl ester inducing photosensitizing porphyrins. These drugs do not induce strong generalized cutaneous photosensitization like the systemically applied porphyrins or their derivatives. For dermatological purposes incoherent lamps or LED arrays can be used for light activation. Depending on the applied light dose and the concentration of the photosensitizer either cytotoxic effects resulting in tumor destruction or immunomodulatory effects improving the inflammatory conditions occur. Treating superficial oncologic lesions (tumor thickness < 2-3 mm) cure rates achieved by PDT are equal to the cure rates of the respective standard therapeutic procedure. The benefits of PDT are the low level of invasiveness and the excellent cosmetic results after treatment. PMID:20930696

  9. Integrating spheres for improved skin photodynamic therapy.

    PubMed

    Glennie, Diana L; Farrell, Thomas J; Hayward, Joseph E; Patterson, Michael S

    2010-01-01

    The prescribed radiant exposures for photodynamic therapy (PDT) of superficial skin cancers are chosen empirically to maximize the success of the treatment while minimizing adverse reactions for the majority of patients. They do not take into account the wide range of tissue optical properties for human skin, contributing to relatively low treatment success rates. Additionally, treatment times can be unnecessarily long for large treatment areas if the laser power is not sufficient. Both of these concerns can be addressed by the incorporation of an integrating sphere into the irradiation apparatus. The light fluence rate can be increased by as much as 100%, depending on the tissue optical properties. This improvement can be determined in advance of treatment by measuring the reflectance from the tissue through a side port on the integrating sphere, allowing for patient-specific treatment times. The sphere is also effective at improving beam flatness, and reducing the penumbra, creating a more uniform light field. The side port reflectance measurements are also related to the tissue transport albedo, enabling an approximation of the penetration depth, which is useful for real-time light dosimetry. PMID:21054127

  10. Photodynamic therapy in lung and gastrointestinal cancers.

    PubMed

    Karanov, S; Kostadinov, D; Shopova, M; Kurtev, P

    1990-06-01

    Twelve central bronchial carcinoma patients and two gastrointestinal (GI) tract (oesophageal and colonic) early-stage cancer patients were treated with photodynamic therapy (PDT). Haematoporphyrin (HP/5, Jacopo Monico, Italy) at a dose of 5 mg kg-1 body weight was used as photosensitizer. Laser light at 628.2-630 nm generated by two different laser systems (gold vapour laser (I.P. Optics, Sofia, Bulgaria) in lung cancer cases and an argon dye laser system (Spectra Physics, Mountain View, U.S.A.) in GI tract cancers) was used. Lung cancers were irradiated 48 h after drug administration and GI tract cancers were irradiated 72 h after infusion of the photosensitizer. Both tumour sites were treated with a total energy dose in the range 350-600 J cm-2. Efficiency of PDT in lung cancer was evaluated by X-rays and endoscopic and functional respiratory tests for bronchial de-obstruction. Complete remission after PDT of GI tract cancers was considered to be tumour eradication (histologically and cytologically proved) and a tumour-free interval of at least 12 months. PMID:2121932

  11. PDT Dose Dosimeter for Pleural Photodynamic Therapy

    PubMed Central

    Kim, Michele M.; Darafsheh, Arash; Ahmad, Mahmoud; Finlay, Jarod C.; Zhu, Timothy C.

    2016-01-01

    PDT dose is the product of the photosensitizer concentration and the light fluence in the target tissue. For improved dosimetry during plural photodynamic therapy (PDT), a PDT dose dosimeter was developed to measure both the light fluence and the photosensitizer concentration simultaneously in the same treatment location. Light fluence and spectral data were rigorously compared to other methods of measurement (e.g. photodiode, multi-fiber spectroscopy contact probe) to assess the accuracy of the measurements as well as their uncertainty. Photosensitizer concentration was obtained by measuring the fluorescence of the sensitizer excited by the treatment light. Fluence rate based on the intensity of the laser spectrum was compared to the data obtained by direct measurement of fluence rate by a fiber-coupled photodiode. Phantom studies were done to obtain an optical property correction for the fluorescence signal. Measurements were performed in patients treated Photofrin for different locations in the pleural cavity. Multiple sites were measured to investigate the heterogeneity of the cavity and to provide cross-validation via relative dosimetry. This novel method will allow for accurate real-time determination of delivered PDT dose and improved PDT dosimetry. PMID:27053825

  12. 5-ALA based photodynamic management of glioblastoma

    NASA Astrophysics Data System (ADS)

    Rühm, Adrian; Stepp, Herbert; Beyer, Wolfgang; Hennig, Georg; Pongratz, Thomas; Sroka, Ronald; Schnell, Oliver; Tonn, Jörg-Christian; Kreth, Friedrich-Wilhelm

    2014-03-01

    Objective: Improvement of the clinical outcome of glioblastoma (GBM) patients by employment of fluorescence and photosensitization on the basis of 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX). Methods: In this report the focus is laid on the use of tumor selective PpIX fluorescence for stereotactic biopsy sampling and intra-operative treatment monitoring. In addition, our current concept for treatment planning is presented. For stereotactic interstitial photodynamic therapy (iPDT), radial diffusers were implanted into the contrast enhancing tumor volume. Spectroscopic measurements of laser light transmission and fluorescence between adjacent fibers were performed prior, during and post PDT. Results: PpIX concentrations in primary glioblastoma tissue show high intra- and inter-patient variability, but are usually sufficient for an effective PDT. During individual treatment attempts with 5-ALA based GBM-iPDT, transmission and fluorescence measurements between radial diffusers gave the following results: 1. In some cases, transmission after PDT is considerably reduced compared to the value before PDT, which may be attributable to a depletion of oxygenated hemoglobin and/or diffuse bleeding. 2. PpIX fluorescence is efficiently photobleached during PDT in all cases. Conclusion: iPDT with assessment of PpIX fluorescence and photobleaching is a promising treatment option. Individualization of treatment parameters appears to bear a potential to further improve clinical outcomes.

  13. Tissue temperature monitoring during interstitial photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Svensson, Jenny; Johansson, Ann; Svanberg, Katarina; Andersson-Engels, Stefan

    2005-04-01

    During δ-aminolevulinic acid (ALA) based Interstitial Photodynamic Therapy (IPDT) a high light fluence rate is present close to the source fibers. This might induce an unintentional tissue temperature increase of importance for the treatment outcome. In a previous study, we have observed, that the absorption in the tissue increases during the treatment. A system to measure the local tissue temperature at the source fibers during IPDT on tissue phantoms is presented. The temperature was measured by acquiring the fluorescence from small Cr3+-doped crystals attached to the tip of the illumination fiber used in an IPDT-system. The fluorescence of the Alexandrite crystal used is temperature dependent. A ratio of the intensity of the fluorescence was formed between two different wavelength bands in the red region. The system was calibrated by immersing the fibers in an Intralipid solution placed in a temperature controlled oven. Measurements were then performed by placing the fibers interstitially in a pork chop as a tissue phantom. Measurements were also performed superficially on skin on a volunteer. A treatment was conducted for 10 minutes, and the fluorescence was measured each minute during the illumination. The fluorescence yielded the temperature at the fiber tip through the calibration curve. The measurements indicate a temperature increase of a few degrees during the simulated treatment.

  14. Optical dosimetry for interstitial photodynamic therapy

    SciTech Connect

    Arnfield, M.R.; Tulip, J.; Chetner, M.; McPhee, M.S. )

    1989-07-01

    An approach to photodynamic treatment of tumors is the interstitial implantation of fiber optic light sources. Dosimetry is critical in identifying regions of low light intensity in the tumor which may prevent tumor cure. We describe a numerical technique for calculating light distributions within tumors, from multiple fiber optic sources. The method was tested using four translucent plastic needles, which were placed in a 0.94 X 0.94 cm grid pattern within excised Dunning R3327-AT rat prostate tumors. A cylindrical diffusing fiber tip, illuminated by 630 nm dye laser light was placed within one needle and a miniature light detector was placed within another. The average penetration depth in the tumor region between the two needles was calculated from the optical power measured by the detector, using a modified diffusion theory. Repeating the procedure for each pair of needles revealed significant variations in penetration depth within individual tumors. Average values of penetration depth, absorption coefficient, scattering coefficient, and mean scattering cosine were 0.282 cm, 0.469 cm-1, 250 cm-1 and 0.964, respectively. Calculated light distributions from four cylindrical sources in tumors gave reasonable agreement with direct light measurements using fiber optic probes.

  15. Photodynamic therapy of malignant mesothelioma of pleura

    NASA Astrophysics Data System (ADS)

    Warloe, Trond; Heyerdahl, Helen; Peng, Qian; Hoie, J.; Normann, E.; Solheim, O.; Moan, Johan; Giercksky, Karl-Erik

    1995-03-01

    Nine patients with malignant pleural mesothelioma underwent extensive surgery followed by intra-operative photodynamic therapy. Two mg/kg Photofrin was given 48 hours prior to surgery. The thoracic cavity and eventual remaining lung were exposed to 15 - 30 Joules/cm2 of 630 nm laser light. Tumor tissue was analyzed by microscopic photometrical techniques. Five patients with mixed or epithelioid tumors with fluorescence intensity > 100 gray level/pixel seemed to benefit from the given therapy. One patient was free of disease 18 months after treatment. Two patients were treated for metastasis after 12 months with no sign of intrathoracic recurrence. Both are still alive, one without further sign of disease 32 months after initial treatment. Two patients presented generalized disease after 9 and 13 months and intrathoracic recurrence several months later. Two patients with poorly differentiated tumors and 2 patients with moderate to highly differentiated tumors, but with fluorescence intensity < 100 gray level/pixel, presented recurrences after 4 months. PDT-efficiency seems to be predicted by the intensity and distribution of drug-induced fluorescence in tumor tissue. PDT may enhance the possibility to achieve complete local tumor control after excision. Multimodal therapeutic approach of local and systemic disease seems mandatory to further improve survival.

  16. Variables in photodynamic therapy for Barrett's esophagus

    NASA Astrophysics Data System (ADS)

    Jones, Linda R.; Preyer, Norris W.; Buchanan, Jane; Reynolds, Daryl M.; Wolfsen, Herbert C.; Wallace, Michael B.; Gill, Kanwar R. S.

    2009-06-01

    Photodynamic therapy with porfimer sodium (PS) is a treatment option for high grade dysplasia associated with Barrett's esophagus. This study sought to investigate the optical properties of Barrett's dysplasia that may be useful in light dosimetry planning and to determine the effect of PS on tissue absorption and scattering. Fiber optic reflectance spectra were collected before and 48 hours after administration of 2 mg/kg PS. Mucosal biopsies were collected at the same locations. According to Monte Carlo analysis, the fiber optic probe sampled only the mucosal layer. A mathematical fit of the reflectance spectra was performed as a function of blood volume fraction, oxygen saturation and scattering. The average calculated blood volume was 100% higher in Barrett's tissue than normal esophageal tissue. The average scattering slope from 620 to 750 nm was 26% higher for Barrett's dysplasia than normal esophageal tissue, indicating an increase in the size of scattering particles. The difference in the scattering amplitude was not statistically significant, suggesting no significant increase in the number of scattering particles. PS tissue content was determined with extraction methods. Changes in the scattering slope due to PS sensitization were observed; however they were not proportional to the extracted PS concentration.

  17. PDT dose dosimeter for pleural photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Kim, Michele M.; Darafsheh, Arash; Ahmad, Mahmoud; Finlay, Jarod C.; Zhu, Timothy C.

    2016-03-01

    PDT dose is the product of the photosensitizer concentration and the light fluence in the target tissue. For improved dosimetry during plural photodynamic therapy (PDT), a PDT dose dosimeter was developed to measure both the light fluence and the photosensitizer concentration simultaneously in the same treatment location. Light fluence and spectral data were rigorously compared to other methods of measurement (e.g. photodiode, multi-fiber spectroscopy contact probe) to assess the accuracy of the measurements as well as their uncertainty. Photosensitizer concentration was obtained by measuring the fluorescence of the sensitizer excited by the treatment light. Fluence rate based on the intensity of the laser spectrum was compared to the data obtained by direct measurement of fluence rate by a fiber-coupled photodiode. Phantom studies were done to obtain an optical property correction for the fluorescence signal. Measurements were performed in patients treated Photofrin for different locations in the pleural cavity. Multiple sites were measured to investigate the heterogeneity of the cavity and to provide cross-validation via relative dosimetry. This novel method will allow for accurate real-time determination of delivered PDT dose and improved PDT dosimetry.

  18. Photodynamic therapy of recurrent cerebral glioma

    NASA Astrophysics Data System (ADS)

    Zhu, Shu-Gan; Wu, Si-En; Chen, Zong-Qian; Sun, Wei

    1993-03-01

    Photodynamic therapy (PDT) was performed on 11 cases of recurrent cerebral glioma, including 3 cases of recurrent glioblastoma, 7 of recurrent anaplastic astrocytoma, and 1 recurrent ependymoma. Hematoporphyrin derivative (HPD) was administered intravenously at a dose of 4 - 7 mg/kg 5 - 24 hours before the operation. All patients underwent a craniotomy with a nearly radical excision of the tumor following which the tumor bed was irradiated with 630 nm laser light emitting either an argon pumped dye laser or frequency double YAG pumped dye laser for 30 to 80 minutes with a total dose of 50 J/cm2 (n equals 1), 100 J/cm2 (n equals 2), 200 J/cm2 (n equals 7), and 300 J/cm2 (n equals 1). The temperature was kept below 37 degree(s)C by irrigation. Two patients underwent postoperative radiotherapy. There was no evidence of increased cerebral edema, and no other toxicity by the therapy. All patients were discharged from the hospital within 15 days after surgery. We conclude that PDT using 4 - 7 mg/kg of HPD and 630 nm light with a dose of up to 300 J/cm2 can be used as an adjuvant therapy with no additional complications. Adjuvant PDT in the treatment of recurrent glioma is better than simple surgery.

  19. Photodynamic Antimicrobial Polymers for Infection Control

    PubMed Central

    McCoy, Colin P.; O’Neil, Edward J.; Cowley, John F.; Carson, Louise; De Baróid, Áine T.; Gdowski, Greg T.; Gorman, Sean P.; Jones, David S.

    2014-01-01

    Hospital-acquired infections pose both a major risk to patient wellbeing and an economic burden on global healthcare systems, with the problem compounded by the emergence of multidrug resistant and biocide tolerant bacterial pathogens. Many inanimate surfaces can act as a reservoir for infection, and adequate disinfection is difficult to achieve and requires direct intervention. In this study we demonstrate the preparation and performance of materials with inherent photodynamic, surface-active, persistent antimicrobial properties through the incorporation of photosensitizers into high density poly(ethylene) (HDPE) using hot-melt extrusion, which require no external intervention except a source of visible light. Our aim is to prevent bacterial adherence to these surfaces and eliminate them as reservoirs of nosocomial pathogens, thus presenting a valuable advance in infection control. A two-layer system with one layer comprising photosensitizer-incorporated HDPE, and one layer comprising HDPE alone is also described to demonstrate the versatility of our approach. The photosensitizer-incorporated materials are capable of reducing the adherence of viable bacteria by up to 3.62 Log colony forming units (CFU) per square centimeter of material surface for methicillin resistant Staphylococcus aureus (MRSA), and by up to 1.51 Log CFU/cm2 for Escherichia coli. Potential applications for the technology are in antimicrobial coatings for, or materials comprising objects, such as tubing, collection bags, handrails, finger-plates on hospital doors, or medical equipment found in the healthcare setting. PMID:25250740

  20. Photodynamic therapy in head and neck cancer.

    PubMed

    Nelke, Kamil H; Pawlak, Wojciech; Leszczyszyn, Jarosław; Gerber, Hanna

    2014-01-01

    Photodynamic therapy (PDT) is a special type of treatment involving the use of a photosensitizer or a photosensitizing agent along with a special type of light, which, combined together, induces production of a form of oxygen that is used to kill surrounding cells in different areas of the human body. Specification of the head and neck region requires different approaches due to the surrounding of vital structures. PDT can also be used to treat cells invaded with infections such as fungi, bacteria and viruses. The light beam placed in tumor sites activates locally applied drugs and kills the cancer cells. Many studies are taking place in order to invent better photosensitizers, working on a larger scale and to treat deeply placed and larger tumors. It seems that PDT could be used as an alternative surgical treatment in some tumor types; however, all clinicians should be aware that the surgical approach is still the treatment of choice. PDT is a very accurate and effective therapy, especially in early stages of head and neck squamous cell carcinomas (HNSCC), and can greatly affect surgical outcomes in cancerous patients. We present a detailed review about photosensitizers, their use, and therapeutic advantages and disadvantages. PMID:24491903

  1. Palliation of esophageal malignancy with photodynamic therapy.

    PubMed

    McCaughan, J S; Williams, T E; Bethel, B H

    1985-08-01

    Sixteen patients with esophageal malignancies received photodynamic therapy after 3 mg of hematoporphyrin derivative (Photofrin I) or 2 mg of Photofrin II per kilogram of body weight was injected intravenously two to six days prior to treatment. A tunable dye argon laser system delivered 630 nm light through quartz fibers passed through the biopsy channel of a gastroscope. All patients obtained improvement in swallowing, usually from total obstruction or clear liquids only to a regular diet within three weeks and with new techniques, at least liquids within three days of treatment. Karnofsky Performance Status (KPS) and esophageal grades were measured before treatment, 1 month following treatment, and periodically until death. Ten patients died an average of 3.7 months after initial treatment (range, 0.6 to 19 months). Six patients are alive at 11, 10, 5, 2.5, 2 months, and 1 month after treatment. The median survival of 12 patients treated more than 6 months ago was 6.5 months and of 9 patients with an initial KPS higher than 30, 8.1 months. PMID:2411233

  2. Photodynamic inactivation of pathogens causing infectious keratitis

    NASA Astrophysics Data System (ADS)

    Simon, Carole; Wolf, G.; Walther, M.; Winkler, K.; Finke, M.; Hüttenberger, D.; Bischoff, Markus; Seitz, B.; Cullum, J.; Foth, H.-J.

    2014-03-01

    The increasing prevalence of antibiotic resistance requires new approaches also for the treatment of infectious keratitis. Photodynamic Inactivation (PDI) using the photosensitizer (PS) Chlorin e6 (Ce6) was investigated as an alternative to antibiotic treatment. An in-vitro cornea model was established using porcine eyes. The uptake of Ce6 by bacteria and the diffusion of the PS in the individual layers of corneal tissue were investigated by fluorescence. After removal of the cornea's epithelium Ce6-concentrations < 1 mM were sufficient to reach a penetration depth of 500 μm. Liquid cultures of microorganisms were irradiated using a specially constructed illumination chamber made of Spectralon(R) (reflectance: 99 %), which was equipped with high power light emitting diodes (λ = 670 nm). Clinical isolates of Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) from keratitis patients were tested in liquid culture against different concentrations of Ce6 (1 - 512 μM) using 10 minutes irradiation (E = 18 J/cm2 ). This demonstrated that a complete inactivation of the pathogen strains were feasible whereby SA was slightly more susceptible than PA. 3909 mutants of the Keio collection of Escherichia coli (E.coli) were screened for potential resistance factors. The sensitive mutants can be grouped into three categories: transport mutants, mutants in lipopolysaccharide synthesis and mutants in the bacterial SOS-response. In conclusion PDI is seen as a promising therapy concept for infectious keratitis.

  3. Combination immunotherapy and photodynamic therapy for cancer

    NASA Astrophysics Data System (ADS)

    Hamblin, Michael R.; Castano, Ana P.; Mroz, Pawel

    2006-02-01

    Cancer is a leading cause of death among modern people largely due to metastatic disease. The ideal cancer treatment should target both the primary tumor and the metastases with minimal toxicity towards normal tissue. This is best accomplished by priming the body's immune system to recognize the tumor antigens so that after the primary tumor is destroyed, distant metastases will also be eradicated. Photodynamic therapy (PDT) involves the IV administration of photosensitizers followed by illumination of the tumor with red light producing reactive oxygen species leading to vascular shutdown and tumor cell death. Anti-tumor immunity is stimulated after PDT due to the acute inflammatory response, generation of tumor-specific antigens, and induction of heat-shock proteins. Combination regimens using PDT and immunostimulating treatments are likely to even further enhance post-PDT immunity. These immunostimulants are likely to include products derived from pathogenic microorganisms that are effectively recognized by Toll-like receptors and lead to upregulation of transcription factors for cytokines and inflammatory mediators. The following cascade of events causes activation of macrophages, dendritic and natural killer cells. Exogenous cytokine administration can be another way to increase PDT-induced immunity as well as treatment with a low dose of cyclophosphamide that selectively reduces T-regulatory cells. Although so far these combination therapies have only been used in animal models, their use in clinical trials should receive careful consideration.

  4. Photodynamic therapy of advanced malignant tumors

    NASA Astrophysics Data System (ADS)

    Wang, Lian-xing; Dai, Lu-pin; Lu, Wen-qin

    1993-03-01

    Forty patients with advanced tumors were treated by photodynamic therapy (PDT) from May 1991 to August 1991 in our hospital with age ranges from 30 to 81 years old. The pathological diagnosis shows that 13 had tumors in the colon, 3 in the stomach, 2 in the oesophageal, 2 in the palatum, 1 in the cervix, and 19 others with malignant cancers of the skin. The histology was as follows: squamous cell in 20, adenocarcinoma in 19, melanocarcinoma in 1. By TNM classification there were no cases of T1, 5 cases of T2, and 35 cases of T2 - T3. All patients were stage IV. The overall effective rate was 85%, our experience is that the PDT is suitable for the patients with advanced tumor, especially those whose tumor recurrences are hard to treat after conventional treatment (surgery, radiotherapy, chemotherapy). The PDT appears to be a new and promising possibility to treat advanced tumors and to improve the patients' survival rates.

  5. Photodynamic therapy using a protoporphyrinogen oxidase inhibitor.

    PubMed

    Fingar, V H; Wieman, T J; McMahon, K S; Haydon, P S; Halling, B P; Yuhas, D A; Winkelman, J W

    1997-10-15

    The use of endogenously created porphyrins as an alternative to photosensitizer injection for photodynamic therapy is a rapidly evolving area of study. One common method to induce porphyrin synthesis and accumulation in cells is the topical, oral, or parenteral administration of 5-aminolevulinic acid, a precursor for heme biosynthesis. Porphyrin accumulation may also be elicited by the use of enzyme inhibitors of the heme biosynthetic pathway. Groups of DBA/2 mice bearing SMT-F mammary tumors were placed on a diet containing 0-4000 ppm of a protoporphyrinogen oxidase inhibitor, FP-846. This agent blocks a critical step in porphyrin metabolism and results in elevated intracellular levels of protoporphyrin IX. Light treatment of tumors produced both initial and long-term regression that was dependent on the amount of inhibitor, the duration of inhibitor exposure to animals, and the amount of light used in PDT. Tumor regression occurred without significant destruction of normal tissues in the treatment field and without initial vascular constriction or blood flow stasis. Tumor cure in animals given 4000 ppm FP-846 in feed for 3 days and 300 J/cm2 602-670 nm light (23% cure) was similar to the response in animals given 10 mg/kg Photofrin and the same light dose (20%). PMID:9377568

  6. Photodynamic therapy (PDT) as a biological modifier

    NASA Astrophysics Data System (ADS)

    Obochi, Modestus; Tao, Jing-Song; Hunt, David W. C.; Levy, Julia G.

    1996-04-01

    The capacity of photosensitizers and light to ablate cancerous tissues and unwanted neovasculature constitutes the classical application of photodynamic therapy (PDT). Cell death results from either necrotic or apoptotic processes. The use of photosensitizers and light at doses which do not cause death has been found to affect changes in certain cell populations which profoundly effect their expression of cell surface molecules and secretion of cytokines, thereby altering the functional attributes of the treated cells. Cells of the immune system and the skin may be sensitive to modulation by 'sub-lethal PDT.' Ongoing studies have been conducted to assess, at the molecular level, changes in both lymphocytes and epidermal cells (EC) caused by treatment with low levels of benzoporphyrin derivative monoacid ring A (BPD) (a photosensitizer currently in clinical trials for cancer, psoriasis, endometriosis and age-related macular degeneration) and light. Treatment of skin with BPD and light, at levels which significantly enhanced the length of murine skin allograft acceptance, have been found to down-regulate the expression of Langerhans cell (LC) surface antigen molecules [major histocompatibility complex (MHC) class II and intracellular adhesion molecule (ICAM)-1] and the formation of some cytokines (tumor necrosis factor-alpha (TNF- (alpha) ).

  7. Photodynamic Therapy for Infections: Clinical Applications

    PubMed Central

    Kharkwal, Gitika B.; Sharma, Sulbha K.; Huang, Ying-Ying; Dai, Tianhong; Hamblin, Michael R.

    2012-01-01

    Background and Objective Photodynamic therapy (PDT) was discovered over 100 years ago by its ability to kill various microorganisms when the appropriate dye and light were combined in the presence of oxygen. However it is only in relatively recent times that PDT has been studied as a treatment for various types of localized infections. This resurgence of interest has been partly motivated by the alarming increase in drug resistance amongst bacteria and other pathogens. This review will focus on the clinical applications of antimicrobial PDT. Study Design/Materials and Methods The published peer-reviewed literature was reviewed between 1960 and 2011. Results The basics of antimicrobial PDT are discussed. Clinical applications of antimicrobial PDT to localized viral infections caused by herpes and papilloma viruses, and nonviral dermatological infections such as acne and other yeast, fungal and bacterial skin infections are covered. PDT has been used to treat bacterial infections in brain abscesses and non-healing ulcers. PDT for dental infections including periodontitis and endodontics has been well studied. PDT has also been used for cutaneous Leishmaniasis. Clinical trials of PDT and blue light alone therapy for gastric Helicobacter pylori infection are also covered. Conclusion As yet clinical PDT for infections has been mainly in the field of dermatology using 5-aminolevulanic acid and in dentistry using phenothiazinium dyes. We expect more to see applications of PDT to more challenging infections using advanced antimicrobial photosensitizers targeted to microbial cells in the years to come. PMID:22057503

  8. Novel Photodynamics in Phytochrome & Cyanobacteriochrome Photosensory Proteins

    NASA Astrophysics Data System (ADS)

    Larsen, Delmar

    2015-03-01

    The photodynamics of recently characterized phytochrome and cyanobacteriochrome photoreceptors are discussed. Phytochromes are red/far-red photosensory proteins that utilize the photoisomerization of a linear tetrapyrrole (bilin) chromophore to detect the red to far-red light ratio. Cyanobacteriochromes (CBCRs) are distantly related cyanobacterial photosensors with homologous bilin-binding GAF domains, but exhibit greater spectral diversity. The excited-state mechanisms underlying the initial photoisomerization in the forward reactions of the cyanobacterial photoreceptor Cph1 from Synechocystis, the RcaE CBCR from Fremyella diplosiphon, and Npr6012g4 CBCR from Nostoc punctiforme were contrasted via multipulse pump-dump-probe transient spectroscopy. A rich excited-state dynamics are resolved involving a complex interplay of excited-state proton transfer, photoisomerization, multilayered inhomogeneity, and reactive intermediates, and Le Chatelier redistribution. NpR6012g4 exhibits a high quantum yield for its forward photoreaction (40%) that was ascribed to the activity of hidden, productive ground-state intermediates via a ``second chance initiation dynamics'' (SCID) mechanism. This work was supported by a grant from the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, United States Department of Energy (DOE DE-FG02-09ER16117).

  9. Pecularities of clinical photodynamic therapy of cancer

    NASA Astrophysics Data System (ADS)

    Stranadko, Eugeny P.; Skobelkin, Oleg K.; Litvin, Grigory D.; Astrakhankina, Tamara A.

    1996-01-01

    The analysis of the results of photodynamic therapy (PDT) for treating malignant neoplasms of the skin, mammary glands, tongue, oral mucous, lower lip, larynx, lungs, urinary bladder rectum and other locations has been made. During 1992 - 1995 478 tumoral foci in 125 patients have been treated with PDT. All patients were previously treated with conventional techniques without effect or they were not treated due to contraindications either because of severe accompanying diseases or because of old age. A part of the patients had PDT because of recurrences or intradermal metastases in 1 - 2 years after surgical, radial or combined treatment. Two home-made preparations were used as photosensitizers: Photohem (hematoporphyrine derivative) and Photosense (aluminum sulfonated phthalocyanine). Light sources were: the argon pumped dye laser (`Innova-200', `Coherent') and home-made laser devices: copper-vapor laser-pumped dye laser (`Yakhroma-2', Frjazino), gas-discharge unit `Ksenon' (wavelength 630 nm), gold-vapor laser (wavelength 627.8 nm) for Photohem; while for Photosense sessions we used solid-state laser on ittrium aluminate `Poljus-1' (wavelength 670 nm). Up to now we have follow-up control data within 2 months and 3 years. Positive effect of PDT was seen in 92% of patients including complete regression of tumors in 66.4% and partial in 25.6%. Currently, this new perspective technique of treating malignant neoplasms is successfully being used in Russia; new photosensitizers and light sources for PDT and fluorescent tumor diagnostics are being developed as well.

  10. Photodynamic therapy of cervical intraepithelial neoplasia using hexaminolevulinate and methylaminolevulinate

    NASA Astrophysics Data System (ADS)

    Soergel, Philipp; Staboulidou, Ismini; Hertel, Herrmann; Schippert, Cordula; Hillemanns, Peter

    2009-06-01

    Cervical intraepithelial neoplasia (CIN) is the precursor of invasive cervical cancer. Previous studies indicated that photodynamic therapy (PDT) represents an effective treatment modality in CIN. In 28 patients with CIN 1 - 3, 1 - 2 cycles of PDT were conducted using hexaminolevulinate (HAL) or methylaminolevulinate (MAL) and a special light delivery system. After 6 months, biopsies were obtained to assess response. The overall response rate for complete or partial response was 65%. Photodynamic therapy using new ALA esters is effective and may offer unique advantages in the therapy of CIN.

  11. Photodynamic Therapy: The Imminent Milieu For Treating Oral Lesions

    PubMed Central

    Mohanty, Neeta; Jalaluddin, MD; Kotina, Sreekanth; Routray, Samapika; Ingale, Yashwant

    2013-01-01

    Photodynamic therapy (PDT) is used in curative and palliative treatment of head and neck squamous cell carcinoma (HNSCC) and other oral lesions. Oral infections (such as mucosal and endodontic infections, periodontal diseases, caries, and peri-implantitis) are among the specific targets where PDT can be applied Photodynamic therapy (PDT) efficacy depends on the local dose deposited in the lesion as well as oxygen availability in the lesion. Further long-term clinical studies are necessary in establishing a more specific place of the technique in the field of dentistry. PMID:23905154

  12. Hybrid photoactive fullerene derivative-ruboxyl nanostructures for photodynamic therapy.

    PubMed

    Kotelnikov, Alexander I; Rybkin, Alexander Yu; Khakina, Ekaterina A; Kornev, Alexey B; Barinov, Alexander V; Goryachev, Nikolay S; Ivanchikhina, Anastasiya V; Peregudov, Alexander S; Martynenko, Vyacheslav M; Troshin, Pavel A

    2013-07-14

    Here we report the investigation of photophysical properties and photodynamic action of two novel water soluble hybrid molecular structures based on [60]fullerene dyads bearing covalently attached residues of anthracycline antibiotic "ruboxyl". Molecular structures of the designed compounds were confirmed by IR and UV-VIS absorption spectroscopy, electrospray mass spectrometry (compound 5), and (1)H and (13)C NMR spectroscopy. Dynamic light scattering, steady-state and kinetic fluorimetry and UV-VIS absorption spectroscopy techniques were used to study the behavior of the synthesized hybrid molecular structures in aqueous solutions. Photodynamic activity of the compounds was evaluated by monitoring the O2(-) generation under visible light irradiation using the NBT test. It has been shown that the anthracycline chromophore (ruboxyl moiety possesses no photodynamic activity) behaves as an efficient photosensitizer for the fullerene core operating via the energy and/or the electron transfer pathways. The presented approach opens up wide opportunities for the design of various fullerene-based donor-acceptor systems with enhanced photodynamic properties potentially suitable for biomedicinal applications. PMID:23712714

  13. Photochemical predictive analysis of photodynamic therapy in dermatology

    NASA Astrophysics Data System (ADS)

    Fanjul-Vélez, F.; Salas-García, I.; López-Escobar, M.; Ortega-Quijano, N.; Arce-Diego, J. L.

    2010-02-01

    Photodynamic Therapy is a recent treatment modality that allows malignant tissue destruction. The technique provides a localized effect and good cosmetic results. The application of Photodynamic Therapy is based on the inoculation of a photosensitizer and the posterior irradiation by an optical source. This radiation chemically activates the drug and provokes reactions that lead to tissue necrosis. Nowadays there are fixed clinical Photodynamic Therapy protocols that make use of a particular optical dose and photosensitizer amount. These parameters are independent of the patient and the lesion. In this work we present a Photodynamic Therapy model that tries to predict the effect of the treatment on the skin. First the results of a clinical study in the Dermatology Department of the Marqués de Valdecilla University Hospital are presented. The most common lesions and some unsuccessful cases are stated. The predictive model proposed is based on a 3D optical propagation of radiation by a Monte Carlo approach. Once the optical energy is obtained, a complex photochemical model is employed. This model takes into account the electronic transitions between molecular levels and particles concentrations. As the process of generation of photosensitizer is not homogeneous, the photosensitizer distribution is also taken into account. The optical power of the source, the exposition time and the optochemical characteristics of the tissue can be varied. This implies that these parameters could be adjusted to the particular pathology we are dealing with, so the unsuccessful cases could be better treated.

  14. Photodynamic Inactivation of Bacteria and Biofilms Using Cationic Bacteriochlorins

    NASA Astrophysics Data System (ADS)

    Meerovich, G. A.; Tiganova, I. G.; Makarova, E. A.; Meerovich, I. G.; Romanova Ju., M.; Tolordova, E. R.; Alekseeva, N. V.; Stepanova, T. V.; Yu, Koloskova; Luk'anets, E. A.; Krivospitskaya, N. V.; Sipailo, I. P.; Baikova, T. V.; Loschenov, V. B.; Gonchukov, S. A.

    2016-02-01

    This work is devoted to the study of two new synthetic bacteriochlorins with four and eight cationic substitutes as the photosensitizers in the photodynamic process. The spectral and antibacterial properties of these photosensitizers in saline solution were investigated. It is shown, that the aggregation ability decreases and the antibacterial efficiency grows as the cationic substitute number increases.

  15. Suppression of cucurbit scab on cucumber leaves by photodynamic dyes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this study was to test the ability of the photodynamic dyes bengal rose, toluidine blue, and methylene blue, to protect systemically cucumber plants from cucurbit scab. At the stage of one true leaf, water or aqueous solutions of the dyes were applied to the leaf as droplets. When the se...

  16. Photodynamic Therapy for Barrett's Esophagus and Esophageal Carcinoma

    PubMed Central

    Qumseya, Bashar J.; David, Waseem

    2013-01-01

    This paper reviews the use of photodynamic therapy (PDT) in patients with Barrett's esophagus and esophageal carcinoma. We describe the history of PDT, mechanics, photosensitizers for PDT in patients with esophageal disease. Finally, we discuss its utility and limitations in this setting. PMID:23423151

  17. Photodynamic Therapy in Treatment of Oral Lichen Planus

    PubMed Central

    Mostafa, Diana; Tarakji, Bassel

    2015-01-01

    Oral lichen planus (OLP) is a relatively common chronic immunologic mucocutaneous disorder. Although there are many presenting treatments, some of them proved its failure. Recently, the use of photodynamic therapy (PDT) has been expanding due to its numerous advantages, as it is safe, convenient, and non-invasive and has toxic effect towards selective tissues. This article provides comprehensive review on OLP, its etiology, clinical features and recent non-pharmacological treatments. We also describe the topical PDT and its mechanisms. Our purpose was to evaluate the efficacy of PDT in treatment of OLP through collecting the data of the related clinical studies. We searched in PubMed website for the clinical studies that were reported from 2000 to 2014 using specific keywords: “photodynamic therapy” and “treatment of oral lichen planus”. Inclusion criteria were English publications only were concerned. In the selected studies of photodynamic treatment, adult patients (more than 20 years) were conducted and the OLP lesions were clinically and histologically confirmed. Exclusion criteria were classical and pharmacological treatments of OLP were excluded and also the using of PDT on skin lesions of lichen planus. We established five clinical studies in this review where all of them reported improvement and effectiveness of PDT in treatment of OLP lesions. The main outcome of comparing the related clinical studies is that the photodynamic is considered as a safe, effective and promising treatment modality for OLP. PMID:25883701

  18. Photodynamic Therapy for Malignant Brain Tumors.

    PubMed

    Akimoto, Jiro

    2016-04-15

    Photodynamic therapy (PDT) using talaporfin sodium together with a semiconductor laser was approved in Japan in October 2003 as a less invasive therapy for early-stage lung cancer. The author believes that the principle of PDT would be applicable for controlling the invading front of malignant brain tumors and verified its efficacy through experiments using glioma cell lines and glioma xenograft models. An investigator-initiated clinical study was jointly conducted with Tokyo Women's Medical University with the support of the Japan Medical Association. Patient enrollment was started in May 2009 and a total of 27 patients were enrolled by March 2012. Of 22 patients included in efficacy analysis, 13 patients with newly diagnosed glioblastoma showed progression-free survival of 12 months, progression-free survival at the site of laser irradiation of 20 months, 1-year survival of 100%, and overall survival of 24.8 months. In addition, the safety analysis of the 27 patients showed that adverse events directly related to PDT were mild. PDT was approved in Japan for health insurance coverage as a new intraoperative therapy with the indication for malignant brain tumors in September 2013. Currently, the post-marketing investigation in the accumulated patients has been conducted, and the preparation of guidelines, holding training courses, and dissemination of information on the safe implementation of PDT using web sites and videos, have been promoted. PDT is expected to be a breakthrough for the treatment of malignant glioma as a tumor cell-selective less invasive therapy for the infiltrated functional brain area. PMID:26888042

  19. Animal models for photodynamic therapy (PDT)

    PubMed Central

    Silva, Zenildo Santos; Bussadori, Sandra Kalil; Fernandes, Kristianne Porta Santos; Huang, Ying-Ying; Hamblin, Michael R.

    2015-01-01

    Photodynamic therapy (PDT) employs non-toxic dyes called photosensitizers (PSs), which absorb visible light to give the excited singlet state, followed by the long-lived triplet state that can undergo photochemistry. In the presence of ambient oxygen, reactive oxygen species (ROS), such as singlet oxygen and hydroxyl radicals are formed that are able to kill cancer cells, inactivate microbial pathogens and destroy unwanted tissue. Although there are already several clinically approved PSs for various disease indications, many studies around the world are using animal models to investigate the further utility of PDT. The present review will cover the main groups of animal models that have been described in the literature. Cancer comprises the single biggest group of models including syngeneic mouse/rat tumours that can either be subcutaneous or orthotopic and allow the study of anti-tumour immune response; human tumours that need to be implanted in immunosuppressed hosts; carcinogen-induced tumours; and mice that have been genetically engineered to develop cancer (often by pathways similar to those in patients). Infections are the second biggest class of animal models and the anatomical sites include wounds, burns, oral cavity, ears, eyes, nose etc. Responsible pathogens can include Gram-positive and Gram-negative bacteria, fungi, viruses and parasites. A smaller and diverse group of miscellaneous animal models have been reported that allow PDT to be tested in ophthalmology, atherosclerosis, atrial fibrillation, dermatology and wound healing. Successful studies using animal models of PDT are blazing the trail for tomorrow's clinical approvals. PMID:26415497

  20. Important cellular targets for antimicrobial photodynamic therapy.

    PubMed

    Awad, Mariam M; Tovmasyan, Artak; Craik, James D; Batinic-Haberle, Ines; Benov, Ludmil T

    2016-09-01

    The persistent problem of antibiotic resistance has created a strong demand for new methods for therapy and disinfection. Photodynamic inactivation (PDI) of microbes has demonstrated promising results for eradication of antibiotic-resistant strains. PDI is based on the use of a photosensitive compound (photosensitizer, PS), which upon illumination with visible light generates reactive species capable of damaging and killing microorganisms. Since photogenerated reactive species are short lived, damage is limited to close proximity of the PS. It is reasonable to expect that the larger the number of damaged targets is and the greater their variety is, the higher the efficiency of PDI is and the lower the chances for development of resistance are. Exact molecular mechanisms and specific targets whose damage is essential for microbial inactivation have not been unequivocally established. Two main cellular components, DNA and plasma membrane, are regarded as the most important PDI targets. Using Zn porphyrin-based PSs and Escherichia coli as a model Gram-negative microorganism, we demonstrate that efficient photoinactivation of bacteria can be achieved without detectable DNA modification. Among the cellular components which are modified early during illumination and constitute key PDI targets are cytosolic enzymes, membrane-bound protein complexes, and the plasma membrane. As a result, membrane barrier function is lost, and energy and reducing equivalent production is disrupted, which in turn compromises cell defense mechanisms, thus augmenting the photoinduced oxidative injury. In conclusion, high PDI antimicrobial effectiveness does not necessarily require impairment of a specific critical cellular component and can be achieved by inducing damage to multiple cellular targets. PMID:27221289

  1. Mechanisms of Resistance to Photodynamic Therapy

    PubMed Central

    Casas, Adriana; Di Venosa, Gabriela; Hasan, Tayyaba; Batlle, Alcira

    2013-01-01

    Photodynamic therapy (PDT) involves the administration of a photosensitizer (PS) followed by illumination with visible light, leading to generation of reactive oxygen species. The mechanisms of resistance to PDT ascribed to the PS may be shared with the general mechanisms of drug resistance, and are related to altered drug uptake and efflux rates or altered intracellular trafficking. As a second step, an increased inactivation of oxygen reactive species is also associated to PDT resistance via antioxidant detoxifying enzymes and activation of heat shock proteins. Induction of stress response genes also occurs after PDT, resulting in modulation of proliferation, cell detachment and inducing survival pathways among other multiple extracellular signalling events. In addition, an increased repair of induced damage to proteins, membranes and occasionally to DNA may happen. PDT-induced tissue hypoxia as a result of vascular damage and photochemical oxygen consumption may also contribute to the appearance of resistant cells. The structure of the PS is believed to be a key point in the development of resistance, being probably related to its particular subcellular localization. Although most of the features have already been described for chemoresistance, in many cases, no cross-resistance between PDT and chemotherapy has been reported. These findings are in line with the enhancement of PDT efficacy by combination with chemotherapy. The study of cross resistance in cells with developed resistance against a particular PS challenged against other PS is also highly complex and comprises different mechanisms. In this review we will classify the different features observed in PDT resistance, leading to a comparison with the mechanisms most commonly found in chemo resistant cells. PMID:21568910

  2. Polymeric Nanoparticles for Cancer Photodynamic Therapy.

    PubMed

    Conte, Claudia; Maiolino, Sara; Pellosi, Diogo Silva; Miro, Agnese; Ungaro, Francesca; Quaglia, Fabiana

    2016-01-01

    In chemotherapy a fine balance between therapeutic and toxic effects needs to be found for each patient, adapting standard combination protocols each time. Nanotherapeutics has been introduced into clinical practice for treating tumors with the aim of improving the therapeutic outcome of conventional therapies and of alleviating their toxicity and overcoming multidrug resistance. Photodynamic therapy (PDT) is a clinically approved, minimally invasive procedure emerging in cancer treatment. It involves the administration of a photosensitizer (PS) which, under light irradiation and in the presence of molecular oxygen, produces cytotoxic species. Unfortunately, most PSs lack specificity for tumor cells and are poorly soluble in aqueous media, where they can form aggregates with low photoactivity. Nanotechnological approaches in PDT (nanoPDT) can offer a valid option to deliver PSs in the body and to solve at least some of these issues. Currently, polymeric nanoparticles (NPs) are emerging as nanoPDT system because their features (size, surface properties, and release rate) can be readily manipulated by selecting appropriate materials in a vast range of possible candidates commercially available and by synthesizing novel tailor-made materials. Delivery of PSs through NPs offers a great opportunity to overcome PDT drawbacks based on the concept that a nanocarrier can drive therapeutic concentrations of PS to the tumor cells without generating any harmful effect in non-target tissues. Furthermore, carriers for nanoPDT can surmount solubility issues and the tendency of PS to aggregate, which can severely affect photophysical, chemical, and biological properties. Finally, multimodal NPs carrying different drugs/bioactive species with complementary mechanisms of cancer cell killing and incorporating an imaging agent can be developed. In the following, we describe the principles of PDT use in cancer and the pillars of rational design of nanoPDT carriers dictated by tumor and

  3. [Photodynamic therapy of superficial bladder tumors].

    PubMed

    Misaki, T; Hisazumi, H; Hirata, A; Kunimi, K; Yamamoto, H; Amano, T; Kumaki, O; Koshida, K; Nishino, A; Nakazima, K

    1986-12-01

    Photodynamic therapy (PDT), using hematoporphyrin derivative (HPD) and the red light (wavelength 630 nm) of an argon-dye laser as the source of excitation energy was performed on 46 patients with superficial bladder tumors. Two methods of laser irradiation, (1) focal PDT using a 400 micron quartz fiber through a cystourethroscope in 22 patients with superficial bladder tumors and (2) whole bladder wall total PDT using a motor-driven laser light scattering device in 24 patients with multifocal carcinoma in situ and/or dysplasia of bladder mucosa associated with multicentric concurrent superficial tumors, were used. The patients in (2) had been referred for total cystectomy, and 19 of these 24 patients had a history of several transurethral resections, hyperthermia and/or instillation therapy. HPD 2-4 mg/kg was i.v. injected 48 to 72 hours before PDT. Judging from the results of 60 protrusions treated by focal PDT, the light power should be 200 mW/cm2 for 5-10 minutes or more and the total light energy should be 100 J/cm2 or more in tumors up to 2 cm in size. With focal PDT, 4 of the 22 patients had no recurrence with the mean tumor free time of 20.8 months. In 6 of the 24 patients treated with total PDT using 10, 20 or 30 J/cm2 of light energy, there was no recurrence with a mean tumor-free time of 7.5 months and there was no significant relationship between the recurrence rate and total light energy used. PMID:3825831

  4. Photodynamic Therapy for Malignant Brain Tumors

    PubMed Central

    AKIMOTO, Jiro

    2016-01-01

    Photodynamic therapy (PDT) using talaporfin sodium together with a semiconductor laser was approved in Japan in October 2003 as a less invasive therapy for early-stage lung cancer. The author believes that the principle of PDT would be applicable for controlling the invading front of malignant brain tumors and verified its efficacy through experiments using glioma cell lines and glioma xenograft models. An investigator-initiated clinical study was jointly conducted with Tokyo Women’s Medical University with the support of the Japan Medical Association. Patient enrollment was started in May 2009 and a total of 27 patients were enrolled by March 2012. Of 22 patients included in efficacy analysis, 13 patients with newly diagnosed glioblastoma showed progression-free survival of 12 months, progression-free survival at the site of laser irradiation of 20 months, 1-year survival of 100%, and overall survival of 24.8 months. In addition, the safety analysis of the 27 patients showed that adverse events directly related to PDT were mild. PDT was approved in Japan for health insurance coverage as a new intraoperative therapy with the indication for malignant brain tumors in September 2013. Currently, the post-marketing investigation in the accumulated patients has been conducted, and the preparation of guidelines, holding training courses, and dissemination of information on the safe implementation of PDT using web sites and videos, have been promoted. PDT is expected to be a breakthrough for the treatment of malignant glioma as a tumor cell-selective less invasive therapy for the infiltrated functional brain area. PMID:26888042

  5. How to reuse a one-time pad and other notes on authentication, encryption, and protection of quantum information

    SciTech Connect

    Oppenheim, Jonathan; Horodecki, Michal

    2005-10-15

    Quantum information is a valuable resource which can be encrypted in order to protect it. We consider the size of the one-time pad that is needed to protect quantum information in a number of cases. The situation is dramatically different from the classical case: we prove that one can recycle the one-time pad without compromising security. The protocol for recycling relies on detecting whether eavesdropping has occurred, and further relies on the fact that information contained in the encrypted quantum state cannot be fully accessed. We prove the security of recycling rates when authentication of quantum states is accepted, and when it is rejected. We note that recycling schemes respect a general law of cryptography which we introduce relating the size of private keys, sent qubits, and encrypted messages. We discuss applications for encryption of quantum information in light of the resources needed for teleportation. Potential uses include the protection of resources such as entanglement and the memory of quantum computers. We also introduce another application: encrypted secret sharing and find that one can even reuse the private key that is used to encrypt a classical message. In a number of cases, one finds that the amount of private key needed for authentication or protection is smaller than in the general case.

  6. 24 CFR 203.18c - One-time or up-front mortgage insurance premium excluded from limitations on maximum mortgage...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false One-time or up-front mortgage... INSURANCE Eligibility Requirements and Underwriting Procedures Eligible Mortgages § 203.18c One-time or up... amount of any mortgage may be increased by the amount of any one-time or up-front mortgage...

  7. 24 CFR 203.18c - One-time or up-front mortgage insurance premium excluded from limitations on maximum mortgage...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false One-time or up-front mortgage... INSURANCE Eligibility Requirements and Underwriting Procedures Eligible Mortgages § 203.18c One-time or up... amount of any mortgage may be increased by the amount of any one-time or up-front mortgage...

  8. 24 CFR 203.18c - One-time or up-front mortgage insurance premium excluded from limitations on maximum mortgage...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false One-time or up-front mortgage... INSURANCE Eligibility Requirements and Underwriting Procedures Eligible Mortgages § 203.18c One-time or up... amount of any mortgage may be increased by the amount of any one-time or up-front mortgage...

  9. 24 CFR 203.18c - One-time or up-front mortgage insurance premium excluded from limitations on maximum mortgage...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false One-time or up-front mortgage... INSURANCE Eligibility Requirements and Underwriting Procedures Eligible Mortgages § 203.18c One-time or up... amount of any mortgage may be increased by the amount of any one-time or up-front mortgage...

  10. Potentiation of thermal inactivation of glyceraldehyde-3-phosphate dehydrogenase by photodynamic treatment. A possible model for the synergistic interaction between photodynamic therapy and hyperthermia.

    PubMed Central

    Prinsze, C; Dubbelman, T M; Van Steveninck, J

    1991-01-01

    Thermal inactivation of glyceraldehyde-3-phosphate dehydrogenase appeared to be caused by a conformational mechanism, without involvement of covalent reactions. On the other hand, photodynamic inactivation of the enzyme (induced by illumination in the presence of Photofrin II) was caused by photo-oxidation of the essential thiol group in the active centre. A short photodynamic treatment of the enzyme, leading to only a limited inactivation, caused a pronounced potentiation of subsequent thermal inactivation, as measured over the temperature range 40-50 degrees C. Analysis of the experimental results according to the Arrhenius equation revealed that both the activation energy of thermal inactivation and the frequency factor (the proportionality constant) were significantly decreased by the preceding photodynamic treatment. The experimental results indicate a mechanism in which limited photodynamic treatment induced a conformational change of the protein molecule. This conformational change did not contribute to photodynamic enzyme inhibition, but was responsible for the decreased frequency factor and activation energy of subsequent thermal inactivation of the enzyme. The opposing effects of decreased activation energy and decreased frequency factor resulted in potentiation of thermal inactivation of the enzyme over the temperature range 40-50 degrees C. With other proteins, different results were obtained. With amylase the combined photodynamic and thermal effects were not synergistic, but additive, and photodynamic treatment had no effect on the frequency factor and the activation energy of thermal inactivation. With respect to myoglobin denaturation, the photodynamic and thermal effects were antagonistic over the whole practically applicable temperature range. Limited photodynamic treatment protected the protein against heat-induced precipitation, concomitantly increasing both the frequency factor and the activation energy of the process. These results offer a

  11. A study of the photodynamic effect on cancerous cells A study of the photodynamic effect on cancerous cells

    NASA Astrophysics Data System (ADS)

    AlSalhi, M. S.; Atif, M.; Alobiadi, A. A.; Aldwayyan, A. S.

    2012-08-01

    We use a rate equation model for the loss of the photosensitizer resulting from photo-oxidation (singlet oxygen attack on the photodynamic therapy (PDT) photosensitizer). It also incorporates the effect of photobleaching (photosensitizer decay) on the oxygen and the photosensitizer concentration which play an important role in photodynamic damage in different cell cultures. As a part of this study, we calculated photodynamic damage against the exposure time. Secondly photodynamic damage in different treated malignant/neoplastic as well as normal cell lines (Hep-2, A-549, and WI-38) has been investigated using a continuous wave (CW) He-Ne laser (633 nm of red wavelength). For determination of effectiveness of photodynamic damage two sorts of experiments are conducted. In first step of this experiment, given cell lines were photosensitized/treated with 1 ml of δ-aminolevulinic acid (ALA) having working solution of 200 μg/ml and after 4 hours of time of incubation ALA treated cells were exposed/irradiated with different doses (15 - 60 J/cm2) with constant irradiation time (15 minutes approximately). Same technique with exception of different concentration of ALA (60 - 800 μg/ml) and light dose (15 - 60 J/cm2/5-20 mW of power along with time of irradiation 15 minutes approximately) has been applied in second step of experiment. Finally result has been verified by using staining of mitochondria technique. 633 nm He-Ne (CW) along with 400 μg/ml of 5-ALA stipulates excellent therapeutic results verified by using mitochondrial staining technique as well as cell hemocytometry. Both the experimental as well as theoretical results are in good agreement with each other.

  12. Information verification cryptosystem using one-time keys based on double random phase encoding and public-key cryptography

    NASA Astrophysics Data System (ADS)

    Zhao, Tieyu; Ran, Qiwen; Yuan, Lin; Chi, Yingying; Ma, Jing

    2016-08-01

    A novel image encryption system based on double random phase encoding (DRPE) and RSA public-key algorithm is proposed. The main characteristic of the system is that each encryption process produces a new decryption key (even for the same plaintext), thus the encryption system conforms to the feature of the one-time pad (OTP) cryptography. The other characteristic of the system is the use of fingerprint key. Only with the rightful authorization will the true decryption be obtained, otherwise the decryption will result in noisy images. So the proposed system can be used to determine whether the ciphertext is falsified by attackers. In addition, the system conforms to the basic agreement of asymmetric cryptosystem (ACS) due to the combination with the RSA public-key algorithm. The simulation results show that the encryption scheme has high robustness against the existing attacks.

  13. Deterministic Secure Quantum Communication and Authentication Protocol based on Extended GHZ-W State and Quantum One-time Pad

    NASA Astrophysics Data System (ADS)

    Li, Na; Li, Jian; Li, Lei-Lei; Wang, Zheng; Wang, Tao

    2016-04-01

    A deterministic secure quantum communication and authentication protocol based on extended GHZ-W state and quantum one-time pad is proposed. In the protocol, state |φ -> is used as the carrier. One photon of |φ -> state is sent to Alice, and Alice obtains a random key by measuring photons with bases determined by ID. The information of bases is secret to others except Alice and Bob. Extended GHZ-W states are used as decoy photons, the positions of which in information sequence are encoded with identity string ID of the legal user, and the eavesdropping detection rate reaches 81%. The eavesdropping detection based on extended GHZ-W state combines with authentication and the secret ID ensures the security of the protocol.

  14. Deterministic Secure Quantum Communication and Authentication Protocol based on Extended GHZ-W State and Quantum One-time Pad

    NASA Astrophysics Data System (ADS)

    Li, Na; Li, Jian; Li, Lei-Lei; Wang, Zheng; Wang, Tao

    2016-08-01

    A deterministic secure quantum communication and authentication protocol based on extended GHZ-W state and quantum one-time pad is proposed. In the protocol, state | φ -> is used as the carrier. One photon of | φ -> state is sent to Alice, and Alice obtains a random key by measuring photons with bases determined by ID. The information of bases is secret to others except Alice and Bob. Extended GHZ-W states are used as decoy photons, the positions of which in information sequence are encoded with identity string ID of the legal user, and the eavesdropping detection rate reaches 81%. The eavesdropping detection based on extended GHZ-W state combines with authentication and the secret ID ensures the security of the protocol.

  15. Therapeutic and Aesthetic Uses of Photodynamic Therapy Part three of a five-part series

    PubMed Central

    2008-01-01

    The use of aminolevulinic acid photodynamic therapy and methyl ester of aminolevulinic acid photodynamic therapy has become commonplace in dermatology for the treatment of actinic keratoses, among other clinical entities. An intriguing question that has arisen is whether we can utilize these medicines for a chemopreventive effect; that is, preventing or delaying the onset of actinic keratoses and perhaps nonmelanoma skin cancers. This manuscript reviews the current literature and anecdotal evidence that suggests that aminolevulinic acid photodynamic therapy and methyl ester of aminolevulinic acid photodynamic therapy may indeed be chemopreventive and thus useful in preventing and/or delaying these lesions. PMID:21212845

  16. Enhancement of selectivity for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Bedwell, Joanne

    Photodynamic Therapy (PDT) is a technique for producing localised tissue damage with low power light following prior administration of a photosensitising drug. The promise of PDT has been based on the selective retention of photosensitisers by tumours, but this aspect has been over-emphasised with a maximum ratio of photosensitiser concentration of 3:1, tumour to normal, for extracranial tumours and current drugs. This makes selective tumour necrosis difficult to achieve. This thesis explores ways in which selectivity may be improved. Aluminium sulphonated phthalocyanine (AlSPc) has better photochemical properties than the widely used HpD and Photofrin II, but has the same tumour selectivity, although the ratio was improved marginally using its disulphonated component. However, when used in conjunction with the radioprotective drug W7, in a rat colon cancer model, tumour necrosis was the same as without W7 while there was no damage to adjacent normal colon. A radical new approach is to give 5-aminolaevulinic acid (ALA) which induces endogenous production of the photosensitiser protoporphyrin IX. This improves selectivity in the rat colon cancer to 6:1 (tumour to normal mucosa), but also sensitises the mucosa selectively compared with the underlying muscle (10:1), giving a tumour to muscle ratio of 60:1. This has enormous potential for treating small tumours or areas of dysplasia in a range of hollow organs. ALA also has the major advantages of a short optimum drug to light time (typically 4-6 hours), short duration of skin sensitivity (approximately 24 hours) and it can be given orally with minimal systemic toxicity. This work has also shown in vitro that PDT with AlSPc sensitisation can kill helicohacter pylori at doses unlikely to affect gastric mucosa. In conclusion, by careful choice of photosensitising agents and treatment regimes, it is possible to limit PDT effects to abnormal tissues, and even if there is some normal tissue damage, in most cases, this heals

  17. Trichocyanines: a Red-Hair-Inspired Modular Platform for Dye-Based One-Time-Pad Molecular Cryptography.

    PubMed

    Leone, Loredana; Pezzella, Alessandro; Crescenzi, Orlando; Napolitano, Alessandra; Barone, Vincenzo; d'Ischia, Marco

    2015-06-01

    Current molecular cryptography (MoCryp) systems are almost exclusively based on DNA chemistry and reports of cryptography technologies based on other less complex chemical systems are lacking. We describe herein, as proof of concept, the prototype of the first asymmetric MoCryp system, based on an 8-compound set of a novel bioinspired class of cyanine-type dyes called trichocyanines. These novel acidichromic cyanine-type dyes inspired by red hair pigments were synthesized and characterized with the aid of density functional theory (DFT) calculations. Trichocyanines consist of a modular scaffold easily accessible via an expedient condensation of 3-phenyl- or 3-methyl-2H-1,4-benzothiazines with N-dimethyl- or o-methoxyhydroxy-substituted benzaldehyde or cinnamaldehyde derivatives. The eight representative members synthesized herein can be classified as belonging to two three-state systems tunable through four different control points. This versatile dye platform can generate an expandable palette of colors and appears to be specifically suited to implement an unprecedented single-use asymmetric molecular cryptography system. With this system, we intend to pioneer the translation of digital public-key cryptography into a chemical-coding one-time-pad-like system. PMID:26246999

  18. Trichocyanines: a Red-Hair-Inspired Modular Platform for Dye-Based One-Time-Pad Molecular Cryptography

    PubMed Central

    Leone, Loredana; Pezzella, Alessandro; Crescenzi, Orlando; Napolitano, Alessandra; Barone, Vincenzo; d’Ischia, Marco

    2015-01-01

    Current molecular cryptography (MoCryp) systems are almost exclusively based on DNA chemistry and reports of cryptography technologies based on other less complex chemical systems are lacking. We describe herein, as proof of concept, the prototype of the first asymmetric MoCryp system, based on an 8-compound set of a novel bioinspired class of cyanine-type dyes called trichocyanines. These novel acidichromic cyanine-type dyes inspired by red hair pigments were synthesized and characterized with the aid of density functional theory (DFT) calculations. Trichocyanines consist of a modular scaffold easily accessible via an expedient condensation of 3-phenyl- or 3-methyl-2H-1,4-benzothiazines with N-dimethyl- or o-methoxyhydroxy-substituted benzaldehyde or cinnamaldehyde derivatives. The eight representative members synthesized herein can be classified as belonging to two three-state systems tunable through four different control points. This versatile dye platform can generate an expandable palette of colors and appears to be specifically suited to implement an unprecedented single-use asymmetric molecular cryptography system. With this system, we intend to pioneer the translation of digital public-key cryptography into a chemical-coding one-time-pad-like system. PMID:26246999

  19. Cryptanalysis and improvement of quantum broadcast communication and authentication protocol with a quantum one-time pad

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Hao; Chen, Han-Wu

    2016-08-01

    The security of quantum broadcast communication (QBC) and authentication protocol based on Greenberger–Horne–Zeilinger (GHZ) state and quantum one-time pad is analyzed. It is shown that there are some security issues in this protocol. Firstly, an external eavesdropper can take the intercept–measure–resend attack strategy to eavesdrop on 0.369 bit of every bit of the identity string of each receiver without being detected. Meanwhile, 0.524 bit of every bit of the secret message can be eavesdropped on without being detected. Secondly, an inner receiver can take the intercept–measure–resend attack strategy to eavesdrop on half of the identity string of the other’s definitely without being checked. In addition, an alternative attack called the CNOT-operation attack is discussed. As for the multi-party QBC protocol, the attack efficiency increases with the increase of the number of users. Finally, the QBC protocol is improved to a secure one. Project supported by the National Natural Science Foundation of China (Grant Nos. 61502101 and 61170321), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20140651), the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20110092110024), and the Project Funded by PAPD and CICAEET.

  20. Benzochloroporphyrin derivative photosensitizer-mediated photodynamic therapy for Ewing sarcoma.

    PubMed

    Sun, Mengxiong; Zhou, Chenghao; Zeng, Hui; Yin, Fei; Wang, Zhuoying; Yao, Jianzhong; Hua, Yingqi; Cai, Zhengdong

    2016-07-01

    In this study, we evaluated the photodynamic efficacy of a new photosensitizer, benzochloroporphyrin derivative 18 (BCPD-18), in Ewing sarcoma. We found that BCPD-18 decreased the viability of TC-71 cells irradiated by 670nm laser in a concentration dependent manner. We also observed cells undergoing apoptosis as well as cell cycle arrest at the G2M phase after BCPD-18-mediated photodynamic therapy (BCPD-PDT). In addition, in vivo study (subcutaneous and orthotopic models) showed that BCPD-PDT reduced tumor size, tumor weight and tumor-bearing leg weight. After PDT, apoptosis was shown in vivo. Bax expression was increased, and Bcl-2 expression was decreased. This study provides evidence that BCPD-18 could probably be a useful photosensitizer in PDT for Ewing sarcoma. PMID:27113445

  1. Targeted photodynamic therapy--a promising strategy of tumor treatment.

    PubMed

    Bugaj, Andrzej M

    2011-07-01

    Targeted therapy is a new promising therapeutic strategy, created to overcome growing problems of contemporary medicine, such as drug toxicity and drug resistance. An emerging modality of this approach is targeted photodynamic therapy (TPDT) with the main aim of improving delivery of photosensitizer to cancer tissue and at the same time enhancing specificity and efficiency of PDT. Depending on the mechanism of targeting, we can divide the strategies of TPDT into "passive", "active" and "activatable", where in the latter case the photosensitizer is activated only in the target tissue. In this review, contemporary strategies of TPDT are described, including new innovative concepts, such as targeting assisted by peptides and aptamers, multifunctional nanoplatforms with navigation by magnetic field or "photodynamic molecular beacons" activatable by enzymes and nucleic acid. The imperative of introducing a new paradigm of PDT, focused on the concepts of heterogeneity and dynamic state of tumor, is also called for. PMID:21547329

  2. Photoswitching of salicylidene methylamine: a theoretical photodynamics study.

    PubMed

    Spörkel, Lasse; Jankowska, Joanna; Thiel, Walter

    2015-02-12

    Photoswitching of simple photochromic molecules attracts substantial attention because of its possible role in future photon-driven molecular electronics. Here we model the full photoswitching cycle of a minimal photochromic Schiff base-salicylidene methylamine (SMA). We perform semiempirical nonadiabatic on-the-fly photodynamics simulations at the OM2/MRCI level and thoroughly analyze the structural time evolution and switching efficiency of the system. We also identify and examine in detail the crucial steps in the SMA photochemistry ruled by excited-state intramolecular proton transfer. The results place the investigated model aromatic Schiff base among the promising candidates for novel photoswitching molecular materials. Our study also shows the potential of the semiempirical multireference photodynamics simulations as a tool for early stage molecular photodevice design. PMID:25341075

  3. Use of Photosensitizers in Semisolid Formulations for Microbial Photodynamic Inactivation.

    PubMed

    González-Delgado, José A; Kennedy, Patrick J; Ferreira, Marta; Tomé, João P C; Sarmento, Bruno

    2016-05-26

    Semisolid formulations, such as gels, creams and ointments, have recently contributed to the progression of photodynamic therapy (PDT) and microbial photodynamic inactivation (PDI) in clinical applications. The most important challenges facing this field are the physicochemical properties of photosensitizers (PSs), optimal drug release profiles, and the photosensitivity of surrounding tissues. By further integration of nanotechnology with semisolid formulations, very promising pharmaceuticals have been generated against several dermatological diseases (PDT) and (antibiotic-resistant) pathogenic microorganisms (PDI). This review focuses on the different PSs and their associated semisolid formulations currently found in both the market and clinical trials that are used in PDT/PDI. Special emphasis is placed on the advantages that the semisolid formulations bring to drug delivery in PDI. Lastly, some potential considerations for improvement in this field are also discussed. PMID:26569024

  4. Towards image-guided photodynamic therapy of Glioblastoma

    NASA Astrophysics Data System (ADS)

    Mallidi, Srivalleesha; Huang, Huang-Chiao; Liu, Joyce; Mai, Zhiming; Hasan, Tayyaba

    2013-03-01

    Glioblastoma (GBM) is an aggressive cancer with dismal survival rates and few new treatment options. Fluorescence guided resection of GBM followed by photodynamic therapy (PDT) has shown promise in several chemo- or radiotherapy non-responsive GBM treatments clinically. PDT is an emerging light and photosensitizer (PS) mediated cytotoxic method. However, as with other therapeutic modalities, the outcomes are variable largely due to the nonpersonalization of dose parameters. The variability can be attributed to the differences in heterogeneous photosensitizer accumulation in tumors. Building upon our previous findings on utilizing PS fluorescence for designing tumor-specific PDT dose, we explore the use of photoacoustic imaging, a technique that provides contrast based on the tissue optical absorption properties, to obtain 3D information on the tumoral photosensitizer accumulation. The findings of this study will form the basis for customized photodynamic therapy for glioblastoma and have the potential to serve as a platform for treatment of other cancers.

  5. First experience of application of photodynamic therapy in keratoplasty

    NASA Astrophysics Data System (ADS)

    Fyodorov, Svyatoslav N.; Kopayeva, V. G.; Andreev, Yu. V.; Stranadko, Eugeny P.; Ponomariov, G. V.

    1996-12-01

    Vascular effect of photodynamic therapy has been studied in patients with corneal neovascularized transplant in 10 cases. THe injection of photoheme intravenously were made with subsequent irradiation by light of argon-pumped dye laser with light density of 150-300 mW/cm2 for 10-15 minutes. Energy density consisted 150-300 J/cm2. In all the cases at the time of irradiation the aggregated blood flow was appeared followed by blood flow stasis. In post- operative period the vessels disintegrated into separate fragments which disappeared completely after 10-15 days. Taking into account the data of light microscope, the disappearance of the vessels took place as a result of the vascular endothelium lysis along the vascular walls. The vessel alteration study presented in this paper, may also serve to specify the mechanism of photodynamic destruction of neovascularized stroma of tumor.

  6. Anticancer photodynamic therapy based on the use of a microsystem

    NASA Astrophysics Data System (ADS)

    Jastrzebska, E.; Bulka, N.; Zukowski, K.; Chudy, M.; Brzozka, Z.; Dybko, A.

    2015-07-01

    The paper presents the evaluation of photodynamic therapy (PDT) procedures with an application of a microsystem. Two cell lines were used in the experiments, i.e. human lung carcinoma - A549 and normal human fetal lung fibroblast MRC5. Mono-, coculture and mixed cultures were performed in a microsystem at the same time. The microsystem consisted of a concentration gradient generator (CGG) which generates different concentrations of a photosensitizer, and a set of microchambers for cells. The microchambers were linked by microchannels of various length in order to allow cells migration and in this way cocultures were created. Transparent materials were used for the chip manufacture, i.e. glass and poly(dimethylsiloxane). A high power LED was used to test photodynamic therapy effectiveness in the microsystem.

  7. Photodynamic therapy: Promotion of efficacy by a sequential protocol

    PubMed Central

    Kessel, David

    2016-01-01

    Photodynamic therapy (PDT) offers a new approach to selective tumor eradication. Modifications designed to increase and optimize efficacy continue to emerge. Selective photodamage to malignant cells and their environment can bring about tumor cell destruction, shutdown of the tumor vasculature, stimulation of immunologic anti-tumor effects and potentiation of other therapeutic effects. Current development of combination protocols may provide a better rationale for integration of PDT into clinical practice. An example described here is the ability of a sequential (two-sensitizer) PDT protocol to enhance the efficacy of photokilling. The first step involves low-level lysosomal photodamage that has been shown to promote the apoptotic response to subsequent photodynamic effects directed at mitochondria. In this report, we demonstrate the ability of Photofrin, an FDA-approved photosensitizing agent, to serve as either the first or second element of the sequential protocol. PMID:27528795

  8. Photoswitching of Salicylidene Methylamine: A Theoretical Photodynamics Study

    PubMed Central

    2014-01-01

    Photoswitching of simple photochromic molecules attracts substantial attention because of its possible role in future photon-driven molecular electronics. Here we model the full photoswitching cycle of a minimal photochromic Schiff base–salicylidene methylamine (SMA). We perform semiempirical nonadiabatic on-the-fly photodynamics simulations at the OM2/MRCI level and thoroughly analyze the structural time evolution and switching efficiency of the system. We also identify and examine in detail the crucial steps in the SMA photochemistry ruled by excited-state intramolecular proton transfer. The results place the investigated model aromatic Schiff base among the promising candidates for novel photoswitching molecular materials. Our study also shows the potential of the semiempirical multireference photodynamics simulations as a tool for early stage molecular photodevice design. PMID:25341075

  9. Latex carrier for improving protoporphyrin IX for photodynamic therapy.

    PubMed

    Bui, Brian; Liu, Li; Chen, Wei

    2016-06-01

    Attachment of Protoporphyrin IX (PPIX) to poly (styrene-co-4-vinylpyridine) (PS4VP) nanobeads was carried out to improve its properties in aqueous solutions. After using an oil-in-water heated emulsion polymerization technique to synthesize PS4VP, PPIX was bonded to the particles via the carboxylic acid of PPIX hydrogen-bonding to the nitrogen at the surface of PS4VP, thereby preventing self-reactions between the carboxyl groups and the porphyrin core. Refraining the two parts from interacting while attached to the nanobeads prevented PPIX from aggregating, which then increased water solubility, enhanced luminescence and singlet oxygen production. Attachment also improved cell uptake and cell destruction by photodynamic activity. This shows that PS4VP-PPIX may help improve aspects of photodynamic therapy for the treatment of cancer. PMID:27020668

  10. Immune Response Following Photodynamic Therapy For Bladder Cancer

    NASA Astrophysics Data System (ADS)

    Raymond K.

    1989-06-01

    This study was undertaken to determine if photodynamic therapy (PDT) produces an immunologic response in patients treated for bladder cancer. Gamma interferon, interleukin 1-beta, interleukin 2 and tumor necrosis factor-alpha were assayed in the urine of four patients treated with photodynamic therapy for bladder cancer, in seven patients undergoing transurethral procedures, and in five healthy control subjects. Quantifiable concentrations of all cytokines, except gamma interferon, were measured in urine samples from the PDT patients treated with the highest light energies, while no urinary cytokines were found in the PDT patient who received the lowest light energy or in the control subjects. These findings suggest that a local immunologic response may occur following PDT for bladder cancer. Such an immunologic response activated by PDT may be an additional mechanism involved in bladder tumor destruction.

  11. Photodynamic action on some pathogenic microorganisms of oral cavity

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, Ilya S.; Tuchin, Valery V.

    2001-10-01

    The work is devoted to an analysis of pre-clinical and clinical experiments on photodynamic action of HeNe laser radiation in aggregate with a cation thiazinium dye Methylene Blue (MB) on a mix of pathogenic and conditionally pathogenic aerobic bacteria being activators of pyoinflammatory diseases of oral cavity. Concentration of photosensitizes at which there is no own bactericidal influence on dying microflora, and parameters of influence at which the efficiency of irradiated microflora defeat reaches 99 % are determined.

  12. The impact of absorbed photons on antimicrobial photodynamic efficacy.

    PubMed

    Cieplik, Fabian; Pummer, Andreas; Regensburger, Johannes; Hiller, Karl-Anton; Späth, Andreas; Tabenski, Laura; Buchalla, Wolfgang; Maisch, Tim

    2015-01-01

    Due to increasing resistance of pathogens toward standard antimicrobial procedures, alternative approaches that are capable of inactivating pathogens are necessary in support of regular modalities. In this instance, the photodynamic inactivation of bacteria (PIB) may be a promising alternative. For clinical application of PIB it is essential to ensure appropriate comparison of given photosensitizer (PS)-light source systems, which is complicated by distinct absorption and emission characteristics of given PS and their corresponding light sources, respectively. Consequently, in the present study two strategies for adjustment of irradiation parameters were evaluated: (i) matching energy doses applied by respective light sources (common practice) and (ii) by development and application of a formula for adjusting the numbers of photons absorbed by PS upon irradiation by their corresponding light sources. Since according to the photodynamic principle one PS molecule is excited by the absorption of one photon, this formula allows comparison of photodynamic efficacy of distinct PS per excited molecule. In light of this, the antimicrobial photodynamic efficacy of recently developed PS SAPYR was compared to that of clinical standard PS Methylene Blue (MB) regarding inactivation of monospecies biofilms formed by Enterococcus faecalis and Actinomyces naeslundii whereby evaluating both adjustment strategies. PIB with SAPYR exhibited CFU-reductions of 5.1 log10 and 6.5 log10 against E. faecalis and A. naeslundii, respectively, which is declared as a disinfectant efficacy. In contrast, the effect of PIB with MB was smaller when the applied energy dose was adjusted compared to SAPYR (CFU-reductions of 3.4 log10 and 4.2 log10 against E. faecalis and A. naeslundii), or there was even no effect at all when the number of absorbed photons was adjusted compared to SAPYR. Since adjusting the numbers of absorbed photons is the more precise and adequate method from a photophysical point

  13. The impact of absorbed photons on antimicrobial photodynamic efficacy

    PubMed Central

    Cieplik, Fabian; Pummer, Andreas; Regensburger, Johannes; Hiller, Karl-Anton; Späth, Andreas; Tabenski, Laura; Buchalla, Wolfgang; Maisch, Tim

    2015-01-01

    Due to increasing resistance of pathogens toward standard antimicrobial procedures, alternative approaches that are capable of inactivating pathogens are necessary in support of regular modalities. In this instance, the photodynamic inactivation of bacteria (PIB) may be a promising alternative. For clinical application of PIB it is essential to ensure appropriate comparison of given photosensitizer (PS)-light source systems, which is complicated by distinct absorption and emission characteristics of given PS and their corresponding light sources, respectively. Consequently, in the present study two strategies for adjustment of irradiation parameters were evaluated: (i) matching energy doses applied by respective light sources (common practice) and (ii) by development and application of a formula for adjusting the numbers of photons absorbed by PS upon irradiation by their corresponding light sources. Since according to the photodynamic principle one PS molecule is excited by the absorption of one photon, this formula allows comparison of photodynamic efficacy of distinct PS per excited molecule. In light of this, the antimicrobial photodynamic efficacy of recently developed PS SAPYR was compared to that of clinical standard PS Methylene Blue (MB) regarding inactivation of monospecies biofilms formed by Enterococcus faecalis and Actinomyces naeslundii whereby evaluating both adjustment strategies. PIB with SAPYR exhibited CFU-reductions of 5.1 log10 and 6.5 log10 against E. faecalis and A. naeslundii, respectively, which is declared as a disinfectant efficacy. In contrast, the effect of PIB with MB was smaller when the applied energy dose was adjusted compared to SAPYR (CFU-reductions of 3.4 log10 and 4.2 log10 against E. faecalis and A. naeslundii), or there was even no effect at all when the number of absorbed photons was adjusted compared to SAPYR. Since adjusting the numbers of absorbed photons is the more precise and adequate method from a photophysical point

  14. Simultaneous two-photon excitation of photodynamic therapy agents

    SciTech Connect

    Wachter, E.A.; Fisher, W.G. |; Partridge, W.P.; Dees, H.C.; Petersen, M.G.

    1998-01-01

    The spectroscopic and photochemical properties of several photosensitive compounds are compared using conventional single-photon excitation (SPE) and simultaneous two-photon excitation (TPE). TPE is achieved using a mode-locked titanium:sapphire laser, the near infrared output of which allows direct promotion of non-resonant TPE. Excitation spectra and excited state properties of both type 1 and type 2 photodynamic therapy (PDT) agents are examined.

  15. Electroporation enhances antimicrobial photodynamic therapy mediated by the hydrophobic photosensitizer, hypericin, Electroporation enhances antimicrobial photodynamic inactivation

    PubMed Central

    de Melo, Wanessa de Cássia Martins Antunes; Lee, Alexander N; Perussi, Janice Rodrigues; Hamblin, Michael R.

    2013-01-01

    The effective transport of photosensitizers (PS) across the membrane and the intracellular accumulation of PS are the most crucial elements in antimicrobial photodynamic therapy (aPDT). However, due to the morphological complexity of Gram-negative bacteria the penetration of PS is limited, especially hydrophobic PS. Electroporation (EP) could increase the effectiveness of aPDT, by promoting the formation of transient pores that enhance the permeability of the bacterial membrane to PS. In this study we evaluated the combination of aPDT mediated by the hydrophobic PS, hypericin and EP (aPDT/EP) against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. These bacteria were exposed to light (590 nm) in the presence of hypericin (4µM), following electroporation. The results showed that aPDT/EP inactivated 3.67 logs more E. coli and 2.65 logs more S. aureus than aPDT alone. Based on these results we suggest that EP can potentiate the aPDT effect. PMID:24284122

  16. Photodynamic Therapy Plus Chemotherapy Compared with Photodynamic Therapy Alone in Hilar Nonresectable Cholangiocarcinoma

    PubMed Central

    Wentrup, Robert; Winkelmann, Nicola; Mitroshkin, Andrey; Prager, Matthias; Voderholzer, Winfried; Schachschal, Guido; Jürgensen, Christian; Büning, Carsten

    2016-01-01

    Background/Aims Standard treatments are not available for hilar nonresectable cholangiocarcinoma (NCC). It is unknown whether combination therapy of photodynamic therapy (PDT) plus systemic chemotherapy is superior to PDT alone. Methods We retrospectively reviewed 68 patients with hilar NCC treated with either PDT plus chemotherapy (PTD-C) or PDT monotherapy (PDT-M). The primary endpoint was the mean overall survival rate. Secondary endpoints included the 1-year survival rate, risk of cholangitic complications, and outcomes, which were evaluated according to the chemotherapy protocol. Results More than 90% of the study population had advanced hilar NCC Bismuth type III or IV. In the PDT-M group (n=35), the mean survival time was 374 days compared with 520 days in the PDT-C group (n=33, p=0.021). The 1-year survival rate was significantly higher in the PDT-C group compared with the PDT-M group (88% vs 58%, p=0.001) with a significant reduction of mortality (hazard ratio, 0.20; 95% confidence interval, 0.07 to 0.58; p=0.003). Gemcitabine monotherapy resulted in a shorter survival time compared with the gemcitabine combination therapy (mean, 395 days vs 566 days; p=0.09). Cholangitic complications were observed at a similar frequency in the PDT-C and PDT-M groups. Conclusions Combining repeated PDT with a gemcitabine-based combination therapy might offer a significant survival benefit in patients with hilar NCC. PMID:26814610

  17. Nanotechnology-Based Photodynamic Therapy: Concepts, Advances, and Perspectives.

    PubMed

    Garg, Tarun; Jain, Nitin K; Rath, Goutam; Goyal, Amit Kumar

    2015-01-01

    Photodynamic therapy (PDT) is a photoactive process that uses the combination of photosensitizers (PSs) and specific wavelengths of light for the treatment of solid tumors and other diseases. PDT received increased attention after regulatory approval of several photosensitizing drugs and light applicators worldwide. With the advent of newer PSs, the role of PDT in the treatment of cancer and other diseases has been revolutionized. In addition, various targeting strategies developed for site-specific delivery of PSs will be helpful for avoiding phototoxicity to normal tissues. Receptor-mediated targeted PDT approaches using nanocarriers offer the opportunity of enhancing photodynamic efficiency by directly targeting diseased cells and tissues. At present, clinical application of PDT is well established in medicine and surgery. Successfully used in dermatology, urology, gastroenterology, and neurosurgery, PDT has also seen much progress in basic sciences and clinical photodynamics in recent years. Currently, the use of PDT is just beginning, and more research must be performed to prove its therapeutic efficacy. However, nontoxic compounds involved in PDT provide a certain hope that it will evolve to be an effective mechanism for combating chronic diseases. PMID:26559433

  18. Photodynamic therapy in the treatment of basal cell carcinoma

    PubMed Central

    Matei, C; Tampa, M; Poteca, T; Panea-Paunica, G; Georgescu, SR; Ion, RM; Popescu, SM; Giurcaneanu, C

    2013-01-01

    Photodynamic therapy (PDT) is a medical procedure based on the activation of the molecules of various exogenous or endogenous chemical substances called photosensitizers by a light source emitting radiation of an adequate wavelength, usually situated in the visible spectrum; photosensitizers are chemical compounds bearing the capacity to selectively concentrate in the neoplastic cells. The energy captured by the molecules of these substances pervaded in the tumor cells is subsequently discharged in the surrounding tissue, triggering certain photodynamic reactions that result in the destruction of the tumor. The procedure is applicable in numerous medical fields. Skin basal cell carcinoma (BCC), the most frequent type of cancer of the human species, is a cutaneous tumor that responds very well to this innovative treatment method. By reviewing numerous recent studies in the field, this article aims to present the role and the indications of photodynamic therapy in the management of basal cell carcinoma, as well as the most important results achieved so far by this therapy in the field of dermato-oncology. PMID:23599819

  19. Effects of telomerase expression on photodynamic therapy of Barrett's esophagus

    NASA Astrophysics Data System (ADS)

    Wang, Kenneth K.; Anderson, Marlys; Buttar, Navtej; WongKeeSong, Louis-Michel; Borkenhagen, Lynn; Lutzke, Lori

    2003-06-01

    Photodynamic therapy has been applied to Barrett's esophagus and has been shown in prospective randomized studies to eliminate dysplasia as well as decrease the occurrence of cancer. However, the therapy isnot always effective and there are issues with residual areas of Barrett's mucosa despite therapy. There has not been a good explanation for these residual areas and they seem to imply that there may exist a biological mechanisms by which these cells may be resistant to photodynamic therapy. It was our aim to determine if known abnormalities in Barrett's mucosa could be correlated with the lack of response of some of these tissues. We examined the tissue from mulitpel patients who had resonse to therapy as well as those who did not respond. We assessed the tissue for p53 mutations, inactivatino of p16, ploidy status, cell proliferation, telomerase activity, and degree of dysplasia. Interestingly, the only genetic marker than was found to be correlated with lack of reonse was p53 and telomerase activity. This suggests that cells that have lost mechanisms for cell death such as apoptosis or telomere shortengin may be more resistant to photodynamic therapy. In this study, we examined patients before and after PDT for telomerase activity.

  20. Localized electric field of plasmonic nanoplatform enhanced photodynamic tumor therapy.

    PubMed

    Li, Yiye; Wen, Tao; Zhao, Ruifang; Liu, Xixi; Ji, Tianjiao; Wang, Hai; Shi, Xiaowei; Shi, Jian; Wei, Jingyan; Zhao, Yuliang; Wu, Xiaochun; Nie, Guangjun

    2014-11-25

    Near-infrared plasmonic nanoparticles demonstrate great potential in disease theranostic applications. Herein a nanoplatform, composed of mesoporous silica-coated gold nanorods (AuNRs), is tailor-designed to optimize the photodynamic therapy (PDT) for tumor based on the plasmonic effect. The surface plasmon resonance of AuNRs was fine-tuned to overlap with the exciton absorption of indocyanine green (ICG), a near-infrared photodynamic dye with poor photostability and low quantum yield. Such overlap greatly increases the singlet oxygen yield of incorporated ICG by maximizing the local field enhancement, and protecting the ICG molecules against photodegradation by virtue of the high absorption cross section of the AuNRs. The silica shell strongly increased ICG payload with the additional benefit of enhancing ICG photostability by facilitating the formation of ICG aggregates. As-fabricated AuNR@SiO2-ICG nanoplatform enables trimodal imaging, near-infrared fluorescence from ICG, and two-photon luminescence/photoacoustic tomography from the AuNRs. The integrated strategy significantly improved photodynamic destruction of breast tumor cells and inhibited the growth of orthotopic breast tumors in mice, with mild laser irradiation, through a synergistic effect of PDT and photothermal therapy. Our study highlights the effect of local field enhancement in PDT and demonstrates the importance of systematic design of nanoplatform to greatly enhancing the antitumor efficacy. PMID:25375193

  1. Synergistic antimicrobial effect of photodynamic therapy and ciprofloxacin.

    PubMed

    Ronqui, Maria Rita; de Aguiar Coletti, Tatiana Maria Starck Fogaça; de Freitas, Laura Marise; Miranda, Elaine Toscano; Fontana, Carla Raquel

    2016-05-01

    The occurrence of a variety of pathogens resistant to current antibiotics remains the major problem in medical care, especially when bacterial infections are established as biofilms. In this study, we propose the use of photodynamic therapy (PDT) as a monotherapy and associated with antibiotic as an alternative treatment. The aim of this study was to analyze the effects of PDT mediated by methylene blue (MB) on Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) in both biofilm and planktonic phases. Several concentrations of MB and light doses were tested. The bactericidal effects of PDT as a monotherapy did not increase with the concentration of photosensitizer, but were light dose-dependent. In addition, bacteria in biofilms were less affected than cells in the planktonic phase. Although not concentration-dependent, the disruption effect of PDT on biofilms was clearly illustrated by scanning electron microscopy (SEM). We also carried out experiments that evaluated the synergistic effect of photodynamic therapy and the antibiotic ciprofloxacin. The best results were obtained after combination treatment of photodynamic therapy followed by ciprofloxacin on biofilms, which increased bacterial reduction on biofilms, resulting in a 5.4 log reduction for S. aureus biofilm and approximately 7 log for E. coli biofilm. PMID:26971277

  2. Dualities among one-time field theories with spin, emerging from a unifying two-time field theory

    SciTech Connect

    Bars, Itzhak; Quelin, Guillaume

    2008-06-15

    The relation between two-time physics (2T-physics) and the ordinary one-time formulation of physics (1T-physics) is similar to the relation between a 3-dimensional object moving in a room and its multiple shadows moving on walls when projected from different perspectives. The multiple shadows as seen by observers stuck on the wall are analogous to the effects of the 2T-universe as experienced in ordinary 1T spacetime. In this paper we develop some of the quantitative aspects of this 2T to 1T relationship in the context of field theory. We discuss 2T field theory in d+2 dimensions and its shadows in the form of 1T field theories when the theory contains Klein-Gordon, Dirac and Yang-Mills fields, such as the standard model of particles and forces. We show that the shadow 1T field theories must have hidden relations among themselves. These relations take the form of dualities and hidden spacetime symmetries. A subset of the shadows are 1T field theories in different gravitational backgrounds (different space-times) such as the flat Minkowski spacetime, the Robertson-Walker expanding universe, AdS{sub d-k}xS{sup k}, and others, including singular ones. We explicitly construct the duality transformations among this conformally flat subset, and build the generators of their hidden SO(d,2) symmetry. The existence of such hidden relations among 1T field theories, which can be tested by both theory and experiment in 1T-physics, is part of the evidence for the underlying d+2 dimensional spacetime and the unifying 2T-physics structure.

  3. Dualities among one-time field theories with spin, emerging from a unifying two-time field theory

    NASA Astrophysics Data System (ADS)

    Bars, Itzhak; Quélin, Guillaume

    2008-06-01

    The relation between two-time physics (2T-physics) and the ordinary one-time formulation of physics (1T-physics) is similar to the relation between a 3-dimensional object moving in a room and its multiple shadows moving on walls when projected from different perspectives. The multiple shadows as seen by observers stuck on the wall are analogous to the effects of the 2T-universe as experienced in ordinary 1T spacetime. In this paper we develop some of the quantitative aspects of this 2T to 1T relationship in the context of field theory. We discuss 2T field theory in d+2 dimensions and its shadows in the form of 1T field theories when the theory contains Klein-Gordon, Dirac and Yang-Mills fields, such as the standard model of particles and forces. We show that the shadow 1T field theories must have hidden relations among themselves. These relations take the form of dualities and hidden spacetime symmetries. A subset of the shadows are 1T field theories in different gravitational backgrounds (different space-times) such as the flat Minkowski spacetime, the Robertson-Walker expanding universe, AdSd-k×Sk, and others, including singular ones. We explicitly construct the duality transformations among this conformally flat subset, and build the generators of their hidden SO(d,2) symmetry. The existence of such hidden relations among 1T field theories, which can be tested by both theory and experiment in 1T-physics, is part of the evidence for the underlying d+2 dimensional spacetime and the unifying 2T-physics structure.

  4. Protoporphyrin IX fluorescence for enhanced photodynamic diagnosis and photodynamic therapy in murine models of skin and breast cancer

    NASA Astrophysics Data System (ADS)

    Rollakanti, Kishore Reddy

    Protoporphyrin IX (PpIX) is a photosensitizing agent derived from aminolevulinic acid. PpIX accumulates specifically within target cancer cells, where it fluoresces and produces cytotoxic reactive oxygen species. Our aims were to employ PpIX fluorescence to detect squamous cell carcinoma (SCC) of the skin (Photodynamic diagnosis, PDD), and to improve treatment efficacy (Photodynamic therapy, PDT) for basal cell carcinoma (BCC) and cutaneous breast cancer. Hyperspectral imaging and a spectrometer based dosimeter system were used to detect very early SCC in UVB-irradiated murine skin, using PpIX fluorescence. Regarding PDT, we showed that low non-toxic doses of vitamin D, given before ALA application, increase tumor specific PpIX accumulation and sensitize BCC and breast cancer cells to ALA-PDT. These optical imaging methods and the combination therapy regimen (vitamin D and ALA-PDT) are promising tools for effective management of skin and breast cancer.

  5. Towards dual photodynamic and antiangiogenic agents: design and synthesis of a phthalocyanine-chalcone conjugate.

    PubMed

    Tuncel, Sinem; Fournier-dit-Chabert, Jérémie; Albrieux, Florian; Ahsen, Vefa; Ducki, Sylvie; Dumoulin, Fabienne

    2012-02-14

    A phthalocyanine-chalcone conjugate has been designed to combine the vascular disrupting effect of chalcones with the photodynamic effect of phthalocyanines. This potential dual photodynamic and antiangiogenic agent was obtained by the condensation of a tetrahydroxylated non-peripherally substituted Zn(ii) phthalocyanine with an amino chalcone converted into the corresponding activated isocyanate. The conjugate was fully characterized. PMID:22215066

  6. Studies of lipid peroxidation of rat blood after in vivo photodynamic treatment

    NASA Astrophysics Data System (ADS)

    Yanina, Irina Yu.; Navolokin, Nikita A.; Nikitina, Victoria V.; Bucharskaya, Alla B.; Maslyakova, Galina N.; Tuchin, Valery V.

    2011-10-01

    Lipid peroxidation (LP) of blood serum of laboratory animals after in vivo photodynamic treatment was investigated. To determine changes in LP the standard colorimetric test OXYSTAT was used. The results indicate an increase in the intensity of free radical generation in tissues induced by photodynamic treatment.

  7. Studies of lipid peroxidation of rat blood after in vivo photodynamic treatment

    NASA Astrophysics Data System (ADS)

    Yanina, Irina Yu.; Navolokin, Nikita A.; Nikitina, Victoria V.; Bucharskaya, Alla B.; Maslyakova, Galina N.; Tuchin, Valery V.

    2012-03-01

    Lipid peroxidation (LP) of blood serum of laboratory animals after in vivo photodynamic treatment was investigated. To determine changes in LP the standard colorimetric test OXYSTAT was used. The results indicate an increase in the intensity of free radical generation in tissues induced by photodynamic treatment.

  8. Efficient Photodynamic Therapy on Human Retinoblastoma Cell Lines

    PubMed Central

    Walther, Jan; Schastak, Stanislas; Dukic-Stefanovic, Sladjana; Wiedemann, Peter; Neuhaus, Jochen; Claudepierre, Thomas

    2014-01-01

    Photodynamic therapy (PDT) has shown to be a promising technique to treat various forms of malignant neoplasia. The photodynamic eradication of the tumor cells is achieved by applying a photosensitizer either locally or systemically and following local activation through irradiation of the tumor mass with light of a specific wavelength after a certain time of incubation. Due to preferential accumulation of the photosensitizer in tumor cells, this procedure allows a selective inactivation of the malignant tumor while sparing the surrounding tissue to the greatest extent. These features and requirements make the PDT an attractive therapeutic option for the treatment of retinoblastoma, especially when surgical enucleation is a curative option. This extreme solution is still in use in case of tumours that are resistant to conventional chemotherapy or handled too late due to poor access to medical care in less advanced country. In this study we initially conducted in-vitro investigations of the new cationic water-soluble photo sensitizer tetrahydroporphyrin-tetratosylat (THPTS) regarding its photodynamic effect on human Rb-1 and Y79 retinoblastoma cells. We were able to show, that neither the incubation with THPTS without following illumination, nor the sole illumination showed a considerable effect on the proliferation of the retinoblastoma cells, whereas the incubation with THPTS combined with following illumination led to a maximal cytotoxic effect on the tumor cells. Moreover the phototoxicity was lower in normal primary cells from retinal pigmented epithelium demonstrating a higher phototoxic effect of THPTS in cancer cells than in this normal retinal cell type. The results at hand form an encouraging foundation for further in-vivo studies on the therapeutic potential of this promising photosensitizer for the eyeball and vision preserving as well as potentially curative therapy of retinoblastoma. PMID:24498108

  9. Efficient photodynamic therapy on human retinoblastoma cell lines.

    PubMed

    Walther, Jan; Schastak, Stanislas; Dukic-Stefanovic, Sladjana; Wiedemann, Peter; Neuhaus, Jochen; Claudepierre, Thomas

    2014-01-01

    Photodynamic therapy (PDT) has shown to be a promising technique to treat various forms of malignant neoplasia. The photodynamic eradication of the tumor cells is achieved by applying a photosensitizer either locally or systemically and following local activation through irradiation of the tumor mass with light of a specific wavelength after a certain time of incubation. Due to preferential accumulation of the photosensitizer in tumor cells, this procedure allows a selective inactivation of the malignant tumor while sparing the surrounding tissue to the greatest extent. These features and requirements make the PDT an attractive therapeutic option for the treatment of retinoblastoma, especially when surgical enucleation is a curative option. This extreme solution is still in use in case of tumours that are resistant to conventional chemotherapy or handled too late due to poor access to medical care in less advanced country. In this study we initially conducted in-vitro investigations of the new cationic water-soluble photo sensitizer tetrahydroporphyrin-tetratosylat (THPTS) regarding its photodynamic effect on human Rb-1 and Y79 retinoblastoma cells. We were able to show, that neither the incubation with THPTS without following illumination, nor the sole illumination showed a considerable effect on the proliferation of the retinoblastoma cells, whereas the incubation with THPTS combined with following illumination led to a maximal cytotoxic effect on the tumor cells. Moreover the phototoxicity was lower in normal primary cells from retinal pigmented epithelium demonstrating a higher phototoxic effect of THPTS in cancer cells than in this normal retinal cell type. The results at hand form an encouraging foundation for further in-vivo studies on the therapeutic potential of this promising photosensitizer for the eyeball and vision preserving as well as potentially curative therapy of retinoblastoma. PMID:24498108

  10. Aminophthalocyanine-Mediated Photodynamic Inactivation of Leishmania tropica.

    PubMed

    Al-Qahtani, Ahmed; Alkahtani, Saad; Kolli, Bala; Tripathi, Pankaj; Dutta, Sujoy; Al-Kahtane, Abdullah A; Jiang, Xiong-Jie; Ng, Dennis K P; Chang, Kwang Poo

    2016-04-01

    Photodynamic inactivation ofLeishmaniaspp. requires the cellular uptake of photosensitizers, e.g., endocytosis of silicon(IV)-phthalocyanines (PC) axially substituted with bulky ligands. We report here that when substituted with amino-containing ligands, the PCs (PC1 and PC2) were endocytosed and displayed improved potency againstLeishmania tropicapromastigotes and axenic amastigotesin vitro The uptake of these PCs by bothLeishmaniastages followed saturation kinetics, as expected. Sensitive assays were developed for assessing the photodynamic inactivation ofLeishmaniaspp. by rendering them fluorescent in two ways: transfecting promastigotes to express green fluorescent protein (GFP) and loading them with carboxyfluorescein succinimidyl ester (CFSE). PC-sensitizedLeishmania tropicastrains were seen microscopically to lose their motility, structural integrity, and GFP/CFSE fluorescence after exposure to red light (wavelength, ∼650 nm) at a fluence of 1 to 2 J cm(-2) Quantitative fluorescence assays based on the loss of GFP/CFSE from liveLeishmania tropicashowed that PC1 and PC2 dose dependently sensitized both stages for photoinactivation, consistent with the results of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay.Leishmania tropicastrains are >100 times more sensitive than their host cells or macrophages to PC1- and PC2-mediated photoinactivation, judging from the estimated 50% effective concentrations (EC50s) of these cells. Axial substitution of the PC with amino groups instead of other ligands appears to increase its leishmanial photolytic activity by up to 40-fold. PC1 and PC2 are thus potentially useful for photodynamic therapy of leishmaniasis and for oxidative photoinactivation ofLeishmaniaspp. for use as vaccines or vaccine carriers. PMID:26824938

  11. Preclinical studies of photodynamic therapy of intracranial tissues

    NASA Astrophysics Data System (ADS)

    Lilge, Lothar D.; Sepers, Marja; Park, Jane; O'Carroll, Cindy; Pournazari, Poupak; Prosper, Joe; Wilson, Brian C.

    1997-05-01

    The applicability and limitations of the photodynamic threshold model were investigated for an intracranial tumor (VX2) and normal brain tissues in a rabbit model. Photodynamic threshold values for four different photosensitizers, i.e., Photofrin, 5(delta) -aminolaevulinic acid (5(delta) -ALA) induced Protoporphyrin IX (PPIX), Tin Ethyl Etiopurpurin (SnET2), and chloroaluminum phthalocyanine (AlClPc), were determined based on measured light fluence distributions, macroscopic photosensitizer concentration in various brain structures, and histologically determined extent of tissue necrosis following PDT. For Photofrin, AlClPc, and SnET2, normal brain displayed a significantly lower threshold value than VX2 tumor. For 5(delta) -ALA induced PPIX and SnET2 no or very little white matter damage, equalling to very high or infinite threshold values, was observed. Additionally, the latter two photosensitizers showed significantly lower uptake in white matter compared to other brain structures and VX2 tumor. Normal brain structures lacking a blood- brain-barrier, such as the choroid plexus and the meninges, showed high photosensitizer uptake for all photosensitizers, and, hence, are at risk when exposed to light. Results to date suggest that the photodynamic threshold values iares valid for white matter, cortex and VX2 tumor. For clinical PDT of intracranial neoplasms 5(delta) -ALA induced PPIX and SnET2 appear to be the most promising for selective tumor necrosis.However, the photosensitizer concentration in each normal brain structure and the fluence distribution throughout the treatment volume and adjacent tissues at risk must be monitored to maximize the selectivity of PDT for intracranial tumors.

  12. [The randomized study of efficiency of preoperative photodynamic].

    PubMed

    Akopov, A L; Rusanov, A A; Molodtsova, V P; Gerasin, A V; Kazakov, N V; Urtenova, M A; Chistiakov, I V

    2013-01-01

    The authors made a prospective randomized comparison of results of preoperative photodynamic therapy (PhT) with chemotherapy, preoperative chemotherapy in initial unresectable central non-small cell lung cancer in stage III. The efficiency and safety of preoperative therapy were estimated as well as the possibility of subsequent surgical treatment. The research included patients in stage IIIA and IIIB of central non-small cell lung cancer with lesions of primary bronchi and lower section of the trachea, which initially were unresectable, but potentially the patients could be operated on after preoperative treatment. The photodynamic therapy was performed using chlorine E6 and the light of wave length 662 nm. Since January 2008 till December 2011,42 patients were included in the research, 21 patients were randomized in the group for photodynamic therapy and 21--in group without PhT. These groups were compared according to their sex, age, stage of the disease and histological findings. After nonadjuvant treatment the remissions were reached in 19 (90%) patients of the group with PhT and in 16 (76%) patients without PhT and all the patients were operated on. The explorative operations were made on 3 patients out of 16 operated on in the group without PhT (19%). In the group PhT 14 pneumonectomies and 5 lobectomies were perfomed opposite 10 pneumonectomies and 3 lobectomies in group without PhT. The degree of radicalism of resection appears to be reliably higher in the group PhT (RO-89%, R1-11% as against RO-54%, R1-46% in group without PhT), p = 0.038. The preoperative endobronchial PhT conducted with chemotherapy was characterized by efficiency and safety, allowed the surgical treatment and elevated the degree of radicalism of this treatment in selected patients, initially assessed as unresectable. PMID:23808222

  13. Photodynamic therapy potentiates the paracrine endothelial stimulation by colorectal cancer

    NASA Astrophysics Data System (ADS)

    Lamberti, María Julia; Florencia Pansa, María; Emanuel Vera, Renzo; Belén Rumie Vittar, Natalia; Rivarola, Viviana Alicia

    2014-11-01

    Colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer death worldwide. Recurrence is a major problem and is often the ultimate cause of death. In this context, the tumor microenvironment influences tumor progression and is considered as a new essential feature that clearly impacts on treatment outcome, and must therefore be taken into consideration. Photodynamic therapy (PDT), oxygen, light and drug-dependent, is a novel treatment modality when CRC patients are inoperable. Tumor vasculature and parenchyma cells are both potential targets of PDT damage modulating tumor-stroma interactions. In biological activity assessment in photodynamic research, three-dimensional (3D) cultures are essential to integrate biomechanical, biochemical, and biophysical properties that better predict the outcome of oxygen- and drug-dependent medical therapies. Therefore, the objective of this study was to investigate the antitumor effect of methyl 5-aminolevulinic acid-PDT using a light emitting diode for the treatment of CRC cells in a scenario that mimics targeted tissue complexity, providing a potential bridge for the gap between 2D cultures and animal models. Since photodynamic intervention of the tumor microenvironment can effectively modulate the tumor-stroma interaction, it was proposed to characterize the endothelial response to CRC paracrine communication, if one of these two populations is photosensitized. In conclusion, we demonstrated that the dialogue between endothelial and tumor populations when subjected to lethal PDT conditions induces an increase in angiogenic phenotype, and we think that it should be carefully considered for the development of PDT therapeutic protocols.

  14. Uniform irradiation of irregularly shaped cavities for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Rem, Alex I.; van Gemert, Martin J. C.; van der Meulen, Freerk W.; Gijsbers, Geert H. M.; Beek, Johan F.

    1997-03-01

    It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow `integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a cubical box, a sphere, a cylinder and a `bottle-neck' geometry have been investigated experimentally and the results have been compared with computed light distributions obtained using the `radiosity method'. A high reflection coefficient of the mould and the best uniform direct irradiance possible on the inside of the mould were found to be important determinants for achieving a uniform light distribution.

  15. Fluorescent Molecular Imaging and Dosimetry Tools in Photodynamic Therapy

    PubMed Central

    Pogue, Brian W.; Samkoe, Kimberley S.; Gibbs-Strauss, Summer L.; Davis, Scott C.

    2013-01-01

    Measurement of fluorescence and phosphorescence in vivo is readily used to quantify the concentration of specific species that are relevant to photodynamic therapy. However, the tools to make the data quantitatively accurate vary considerably between different applications. Sampling of the signal can be done with point samples, such as specialized fiber probes or from bulk regions with either imaging or sampling, and then in broad region image-guided manner. Each of these methods is described below, the application to imaging photosensitizer uptake is discussed, and developing methods to image molecular responses to therapy are outlined. PMID:20552350

  16. HpD Photobiology And Photodynamic Therapy Of Bladder Carcinoma

    NASA Astrophysics Data System (ADS)

    Lin, Chi-Wei

    1988-02-01

    Bladder carcinoma is considered one of the most favorable targets for the application of photodynamic therapy (PDT) due to the accessibility of the bladder for light delivery. Examination of the bladder and surgical procedures are routinely performed by the insertion of an optical instrument called cystoscope through the urethra. Thus, the treatment of bladder cancer by PDT can be conducted through the cystoscope with minimal invasion. However, to achieve optimal results from this treatment, one must consider both the structure of the bladder and the nature of the carcinoma.

  17. Biomodulatory Approaches to Photodynamic Therapy for Solid Tumors

    PubMed Central

    Anand, Sanjay; Ortel, Bernhard J.; Pereira, Stephen P.; Hasan, Tayyaba; Maytin, Edward V.

    2012-01-01

    Photodynamic Therapy (PDT) uses a photosensitizing drug in combination with visible light to kill cancer cells. PDT has an advantage over surgery or ionizing radiation because PDT can eliminate tumors without causing fibrosis or scarring. Disadvantages include the dual need for drug and light, and a generally lower efficacy for PDT versus surgery. This minireview describes basic principles of PDT, photosensitizers available, and aspects of tumor biology that may provide further opportunities for treatment optimization. An emerging biomodulatory approach, using methotrexate or Vitamin D in combination with aminolevulinate-based PDT, is described. Finally, current clinical uses of PDT for solid malignancies are reviewed. PMID:22842096

  18. Destructive fat tissue engineering using photodynamic and selective photothermal effects

    NASA Astrophysics Data System (ADS)

    Tuchin, Valery V.; Yanina, Irina Yu.; Simonenko, Georgy V.

    2009-02-01

    Destructive fat tissue engineering could be realized using the optical method, which provides reduction of regional or site-specific accumulations of subcutaneous adipose tissue on the cell level. We hypothesize that light irradiation due to photodynamic and selective photothermal effects may lead to fat cell lypolytic activity (the enhancement of lipolysis of cell triglycerides due to expression of lipase activity and cell release of free fat acids (FFAs) due to temporal cell membrane porosity), and cell delayed killing due to apoptosis caused by the induced fat cell stress and/or limited cell necrosis.

  19. 3D Monte Carlo radiation transfer modelling of photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Campbell, C. Louise; Christison, Craig; Brown, C. Tom A.; Wood, Kenneth; Valentine, Ronan M.; Moseley, Harry

    2015-06-01

    The effects of ageing and skin type on Photodynamic Therapy (PDT) for different treatment methods have been theoretically investigated. A multilayered Monte Carlo Radiation Transfer model is presented where both daylight activated PDT and conventional PDT are compared. It was found that light penetrates deeper through older skin with a lighter complexion, which translates into a deeper effective treatment depth. The effect of ageing was found to be larger for darker skin types. The investigation further strengthens the usage of daylight as a potential light source for PDT where effective treatment depths of about 2 mm can be achieved.

  20. Three-dimensional illumination procedure for photodynamic therapy of dermatology

    NASA Astrophysics Data System (ADS)

    Hu, Xiao-ming; Zhang, Feng-juan; Dong, Fei; Zhou, Ya

    2014-09-01

    Light dosimetry is an important parameter that affects the efficacy of photodynamic therapy (PDT). However, the irregular morphologies of lesions complicate lesion segmentation and light irradiance adjustment. Therefore, this study developed an illumination demo system comprising a camera, a digital projector, and a computing unit to solve these problems. A three-dimensional model of a lesion was reconstructed using the developed system. Hierarchical segmentation was achieved with the superpixel algorithm. The expected light dosimetry on the targeted lesion was achieved with the proposed illumination procedure. Accurate control and optimization of light delivery can improve the efficacy of PDT.

  1. Reversible Photodynamic Chloride-Selective Sensor Based on Photochromic Spiropyran

    PubMed Central

    2012-01-01

    We report here for the first time on a reversible photodynamic bulk optode sensor based on the photoswitching of a spiropyran derivative (Sp). The photoswitching of Sp induces a large basicity increase in the polymeric phase, which triggers the extraction of Cl– and H+. Cl– is stabilized by a lipophilic chloride-selective ionophore inside the membrane, while H+ binds with the open form of Sp and induces a spectral change, hence providing the sensor signal. The system was studied with spectroscopic and electrochemical methods. PMID:23036043

  2. Intraoperative photodynamic therapy in laryngeal part of pharynx cancers

    NASA Astrophysics Data System (ADS)

    Loukatch, Erwin V.; Trojan, Vasily; Loukatch, Vjacheslav

    1996-12-01

    In clinic intraoperative photodynamic therapy (IPT) was done in patients with primal squamous cells cancer of the laryngeal part of the pharynx. The He-Ne laser and methylene blue as a photosensibilizator were used. Cobalt therapy in the postoperative period was done in dose 45 Gr. Patients of control groups (1-th group) with only laser and (2-th group) only methylene blue were controlled during three years with the main group. The statistics show certain differences of recidives in the main group compared to the control groups. These facts are allowing us to recommend the use of IPT as an additional method in ENT-oncology diseases treatment.

  3. Optical dosimetry in photodynamic therapy of human uterus and brain

    NASA Astrophysics Data System (ADS)

    Madsen, Steen J.; Svaasand, Lars O.; Hirschberg, Henry; Tadir, Yona; Tromberg, Bruce J.

    1999-06-01

    Optical 'dose' is one of the fundamental parameters required in the design of an efficacious regimen of photodynamic therapy (PDT). The issues involved in delivering a sufficient optical dose to the human uterus and brain during PDT will be discussed. Specifically, measurements of optical properties and fluence rates in excised human uteri are presented. Measured fluence rates are compared to the predictions of a simple diffusion model and the clinical utility of the treatment is discussed. The delivery of light to brain tissue via a surgically implanted balloon applicator will also be considered. The time required to deliver and adequate dose is calculated based on known optical properties and diffusion theory.

  4. On molecular mechanism of the photodynamic therapy of tumors

    NASA Astrophysics Data System (ADS)

    Mostovnikov, Vasili A.; Mostovnikova, Galina R.; Plavski, Vitali Y.; Tretjakov, S. A.

    1995-01-01

    In this work we present the experimental results indicating that the photodestruction (inactivation) of glycolysis enzymes located in mitochondria and responsible for the energy providing of malignant tumors, could serve as a possible molecular mechanism of a photodynamic therapy of cancer. The formation of complexes between the glycolysis enzymes and sensitizer favors can lead to an effective photodestruction of the former [in the experiments lactate dehydrogenase (LDH), pyruvate kinase (PK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and water-soluble tetra(carboxiphenyl)porphyrine [T(CP)P] (the analogue of coprorphyrin) were used as photosensitizer.

  5. Photodynamic therapy with laser scanning mode of tumor irradiation

    NASA Astrophysics Data System (ADS)

    Chepurna, Oksana; Shton, Irina; Kholin, Vladimir; Voytsehovich, Valerii; Popov, Viacheslav; Pavlov, Sergii; Gamaleia, Nikolai; Wójcik, Waldemar; Zhassandykyzy, Maral

    2015-12-01

    In this study we propose a new version of photodynamic therapy performed by laser scanning. The method consists in tumor treatment by a light beam of a small cross section which incrementally moves through the chosen area with a defined delay at each point and repetitively re-scans a zone starting from the initial position. Experimental evaluation of the method in vitro on murine tumor model showed that despite the dose, applied by scanning irradiation mode, was 400 times lower, the tumor inhibition rate conceded to attained with continuous irradiation mode by only 20%.

  6. Synthesis, bioanalysis and biodistribution of photosensitizer conjugates for photodynamic therapy

    PubMed Central

    Denis, Tyler GSt; Hamblin, Michael R

    2013-01-01

    Photodynamic therapy (PDT) was discovered in 1900 by Raab, and has since emerged as a promising tool for treating diseases characterized by unwanted cells or hyperproliferating tissue (e.g., cancer or infectious disease). PDT consists of the light excitation of a photosensitizer (PS) in the presence of O2 to yield highly reactive oxygen species. In recent years, PDT has been improved by the synthesis of targeted bioconjugates between monoclonal antibodies and PS, and by investigating PS biodistribution and PD. Here, we provide a comprehensive review of major developments in PS-immunoconjugate-based PDT and the bioanalysis of these agents, with a specific emphasis on anticancer and antimicrobial PDT. PMID:23641699

  7. Uniform irradiation of irregularly shaped cavities for photodynamic therapy.

    PubMed

    Rem, A I; van Gemert, M J; van der Meulen, F W; Gijsbers, G H; Beek, J F

    1997-03-01

    It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a cubical box, a sphere, a cylinder and a 'bottle-neck' geometry have been investigated experimentally and the results have been compared with computed light distributions obtained using the 'radiosity method'. A high reflection coefficient of the mould and the best uniform direct irradiance possible on the inside of the mould were found to be important determinants for achieving a uniform light distribution. PMID:9080537

  8. Study of photodynamic therapy in skin cancers and precancerous lesions

    NASA Astrophysics Data System (ADS)

    Wang, Jiabi; Gao, Menglin; Wen, Shijun; Wang, Mianjing

    1993-03-01

    Hematoporphyrin photodynamic therapy (HpD-PDT) was used to treat 50 patients (51 lesions) with skin cancers or precancerous lesions. The preliminary results were satisfactory, with 44 cases (45 lesions) obtaining excellent results, 4 cases good, 1 case fair, and 1 case poor. The effective rate was 98%, the significant remission rate 96%, and the complete remission rate 88.2%. Exposure to sunlight should be avoided after HpD injection, since it produces photosensitivity. A follow-up for 1 to 3 years confirmed that HpD-PDT is a good new adjuvant therapy for selected cases. It brings a hopeful future to the treatment of skin cancers.

  9. Two-photon photodynamic properties of TBO-AuNR-in-shell nanoparticles (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wu, Cheng-Han; Yeh, Chen-Sheng; Cheng, Fong-Yu; Tsai, Zen-Uong; Liu, Tzu-Ming

    2016-03-01

    Photodynamic therapy (PDT) is a light-activated chemotherapeutic treatment that utilizes singlet oxygen and reactive oxygen species induced oxidative reactions to react with surrounding biological substrates, which either kills or irreversibly damages malignant cells. We used multiphoton nonlinear optical microscopy to observe the photo-dynamic effects of TBO-AuNR-in-shell NPs. Excited by femtosecond Cr:forsterite laser operating at 1230nm, singlet oxygen were generated through a plasmon-enhanced two-photon nonlinear optical process. For cells took up NPs, this photodynamic effect can kill the cell. From nonlinear optical microscopy images, we found they shrunk after 3 minutes of illumination.

  10. Encapsulation of methylene blue in polyacrylamide nanoparticle platforms protects its photodynamic effectiveness.

    PubMed

    Tang, Wei; Xu, Hao; Park, Edwin J; Philbert, Martin A; Kopelman, Raoul

    2008-05-01

    The ability to prevent methylene blue (MB), a photosensitizer, from being reduced by plasma reductases will greatly improve its efficacy in photodynamic therapy (PDT) applications. We have developed a delivery approach for PDT by encapsulating MB using nanoparticle platforms (NPs). The 30-nm polyacrylamide-based NPs provide protection for the embedded MB against reduction by diaphorase enzymes. Furthermore, our data shows the matrix-protected MB efficiently induces photodynamic damage to tumor cells. The unprecedented results demonstrate the significant in vitro photodynamic effectiveness of MB when encapsulated within NPs, which promises to open new opportunities for MB in its in vivo and clinical studies. PMID:18298950