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1.
Actas urol. esp ; 46(6): 329-339, jul. - ago. 2022. tab
Article in Spanish | IBECS | ID: ibc-208682

ABSTRACT

Objetivo: Evaluar los patrones de práctica clínica de urólogos portugueses en el manejo de pacientes incluidos en un protocolo de vigilancia activa.IntroducciónEl cáncer de próstata (CaP) es una enfermedad heterogénea, con un alto porcentaje de adenocarcinomas indolentes y con una probabilidad baja de convertirse en una enfermedad sintomática o potencialmente mortal. La vigilancia activa (VA) es una forma de tratamiento conservador, empleado con el objetivo de limitar el sobretratamiento de los pacientes con CaP de bajo riesgo. A lo largo de los años, la experiencia con VA ha ido aumentado considerablemente, siendo actualmente el manejo estándar en algunos países. Sin embargo, no existe, a día de hoy, un protocolo universal.MétodosEncuesta electrónica anónima de ámbito nacional, sobre los hábitos y prácticas en materia de VA entre urólogos portugueses. La encuesta constaba de 12preguntas y fue enviada por vía electrónica a los 368 miembros actuales de la Asociación Portuguesa de Urología.ResultadosSe encuestó a 56 urólogos (15,21% de respuestas), distribuidos geográficamente de manera uniforme y categorizados según los años de experiencia y el número de pacientes con CaP tratados mensualmente. La gran mayoría de los encuestados recomienda la VA a sus pacientes, en particular en el caso de pacientes de grado 1 de la ISUP, con un nivel sérico de PSA es inferior a 20 ng/ml. No se cuestiona el cumplimiento de los programas de VA por parte de los pacientes, pero la morbilidad psicológica de albergar la enfermedad es un factor preocupante. Según la mayoría de los encuestados, los protocolos de vigilancia propuestos por las guías internacionales son adecuados y suficientes, pero se ponen de manifiesto algunas limitaciones en cuanto a la disponibilidad de la resonancia magnética de forma periódica y al requerimiento de nuevas biopsias (AU)


Objectiv: To examine clinical practice patterns in locally managing patients under an active surveillance protocol among Portuguese urologists.IntroductionProstate cancer (PCa) is a heterogeneous disease with many prostate adenocarcinomas being indolent and a low probability of ever causing symptoms or death. Active surveillance (AS) is a form of conservative management aimed to reduce over-treatment for low-risk PCa patients. Over the years, experience with AS has grown considerably and is now standard in some countries, however a universal protocol still does not exist.MethodsNationwide anonymous e-survey concerning habits and practices on AS among Portuguese urologists, that consisted of 12questions and was sent electronically to all 368 current members of the Portuguese Urological Association.Results56 urologists were surveyed (15.21% answer rate), evenly distributed geographically and allocated according to years of experience as well as number of PCa patients managed monthly. The vast majority of respondents recommends AS to their patients, particularly ISUP grade 1 patients, whose PSA serum level is bellow 20ng/mL. Observance of AS programs by patients was not in question but concerns exist over psychological morbidity while harboring disease. Majority believed that international guidelines surveillance protocols were adequate and sufficient, but there are some constraints concerning availability of periodic MRIs and re-biopsy needs (AU)


Subject(s)
Humans , Male , Female , Watchful Waiting , Urologists/statistics & numerical data , Prostatic Neoplasms/therapy , Surveillance in Disasters , Practice Patterns, Physicians' , Surveys and Questionnaires , Portugal , Biopsy
2.
Actas Urol Esp (Engl Ed) ; 46(6): 329-339, 2022.
Article in English, Spanish | MEDLINE | ID: mdl-35277378

ABSTRACT

OBJECTIVE: To examine clinical practice patterns in locally managing patients under an active surveillance protocol among Portuguese urologists. INTRODUCTION: Prostate cancer (PCa) is a heterogeneous disease with many prostate adenocarcinomas being indolent and a low probability of ever causing symptoms or death. Active surveillance (AS) is a form of conservative management aimed to reduce over-treatment for low-risk PCa patients. Over the years, experience with AS has grown considerably and is now standard in some countries, however a universal protocol still does not exist. METHODS: Nationwide anonymous e-survey concerning habits and practices on AS among Portuguese urologists, that consisted of twelve questions and was sent electronically to all 368 current members of the Portuguese Urological Association. RESULTS: 56 urologists were surveyed (15.21% answer rate), evenly distributed geographically and allocated according to years of experience as well as number of PCa patients managed monthly. The vast majority of respondents recommends AS to their patients, particularly ISUP grade 1 patients, whose PSA serum level is bellow 20 ng/mL. Observance of AS programs by patients was not in question but concerns exist over psychological morbidity while harboring disease. Majority believed that international guidelines surveillance protocols were adequate and sufficient, but there are some constraints concerning availability of periodic MRIs and re-biopsy needs. CONCLUSIONS: AS seems to be sustained in urologist clinical practice, although patients still lag to adhere and choose for active treatment. AS may not be an easy choice for patients and clinicians due to uncertainty of disease progression, risk of loss to follow-up and repeated biopsies but is also a cause for anxiety, depression, uncertainty and a perception of danger.


Subject(s)
Prostatic Neoplasms , Watchful Waiting , Biopsy , Humans , Male , Portugal/epidemiology , Prostatic Neoplasms/pathology , Urologists
3.
J Biotechnol ; 184: 219-28, 2014 Aug 20.
Article in English | MEDLINE | ID: mdl-24910973

ABSTRACT

A Pichia pastoris transformant carrying the cutinase cDNA of Glomerella cingulata was over-expressed in a 5L bioreactor (2.0L working volume) under fed-batch conditions. Bioreactor experiments rely on varying selected parameters in repeated rounds of optimisation: here these included duration of induction, pH and temperature. Highest cell densities (320gL(-1) wet cell weight) with a cutinase production of 3800mgL(-1) and an activity of 434UmL(-1) were achieved 24h after induction with methanol in basal salt medium (at pH 5 and 28°C). Characterisation of the cutinase showed that it was stable between pH 6 and pH 11, had an optimum pH of 8.0 and retained activity for 30min at 50°C (optimum temperature 25°C).The preferred substrates of G. cingulata cutinase were the medium- to long-chain ρ-nitrophenyl esters of ρ-nitrophenylcaprylate (C8), ρ-nitrophenyllaurate (C12) and ρ-nitrophenylmyristate (C14), with the highest catalytic efficiency, kcat/Km of 7.7±0.7mM(-1)s(-1) for ρ-nitrophenylcaprylate. Microscopic analyses showed that the G. cingulata cutinase was also capable of depolymerising the high molecular weight synthetic polyester, polyethylene terephthalate.


Subject(s)
Batch Cell Culture Techniques/methods , Carboxylic Ester Hydrolases/biosynthesis , Phyllachorales/enzymology , Recombinant Proteins/biosynthesis , Bioreactors , Carboxylic Ester Hydrolases/chemistry , Carboxylic Ester Hydrolases/metabolism , Hydrogen-Ion Concentration , Phyllachorales/genetics , Pichia/genetics , Pichia/growth & development , Polyethylene Terephthalates/chemistry , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Surface-Active Agents/chemistry , Temperature
4.
Commun Agric Appl Biol Sci ; 76(4): 653-9, 2011.
Article in English | MEDLINE | ID: mdl-22702184

ABSTRACT

Arbuscular mycorrhizal fungi are forming the most wide-spread mycorrhizal relationships on Earth. Mycorrhiza contributes to phosphorous acquisition, water absorption and resistance to diseases. The fungus promotes the absorption of nutrients and water from soil, meanwhile the host plant offers photosynthetic assimilates in exchange, like carbohydrates, as energy source. The plant benefits from the contribution of symbiotic partner only when nutrients are in low concentrations in soil and the root system would not be able to absorb sufficiently the minerals. When the help of mycorrhizal fungi is not necessarily needed, the host plant is making an economy of energy, suppressing the development of fungi in the internal radicular space. In this moment, the nature of relationship turns from symbiotic to parasitic, triggering a series of defensive reactions from the plant. Also, there were several cases reported when the presence of arbuscular mycorrhizal fungi negatively influenced the host plant. For example, in adverse environmental conditions, like very high temperatures, instead of determining a higher plant biomass and flowering, the mycorrhiza reduces the growth of the host plant. We conducted a pot experiment with hydroponic culture to examine the effect of arbuscular mycorrhiza on development of French marigold as a host plant. As experimental variants, the phosphorous content in nutrient medium and temperature varied. Plants were artificially infected with arbuscular mycorrhizal fungi using a commercial inoculum containing three fungal species, as following: Glomus intraradices, Glomus etunicatum and Glomus claroideum. Colonization intensity and arbuscular richness were checked using root staining with aniline blue and estimation with the Trouvelot method. To observe the differences between plants from the experimental variants, we examined the number of side shoots, flower buds and fully developed flowers, fresh biomass and total leaf area. Results show that adverse climatic conditions, like temperature shock at the beginning of growing period modified the nature of symbiosis. In this case, the physiological parameters were reduced at colonized plants, while usual, constant growing conditions permitted the normal, efficient and beneficial development of symbiosis.


Subject(s)
Mycorrhizae/physiology , Symbiosis/physiology , Tagetes/microbiology
5.
Stud Health Technol Inform ; 124: 125-30, 2006.
Article in English | MEDLINE | ID: mdl-17108515

ABSTRACT

The recent advances on genomics and proteomics research bring up a significant grow on the information that is publicly available. However, navigating through genetic and bioinformatics databases can be a too complex and unproductive task for a primary care physician. In this paper we present diseasecard, a web portal for rare disease that provides transparently to the user a virtually integration of distributed and heterogeneous information.


Subject(s)
Genomics , Rare Diseases/genetics , Computational Biology , Humans , Information Storage and Retrieval
6.
Adv Space Res ; 30(6): 1533-8, 2002.
Article in English | MEDLINE | ID: mdl-12575718

ABSTRACT

Nucleic acids (combined with protein molecules) are essential constituents of the living systems playing an important role in the early evolution of life as well. A specific feature of these molecules has been found and directly confirmed recently: under the influence of short-wavelength UV radiation bipyrimidine photoproducts (cyclobutane dimers and 6-4 bipyrimidines) are induced and the reversion of them can be provoked by the same photons. However, reversion is preferred by the shorter wavelengths. With increasing ratio of the longer wavelength components of the radiation (using artificial UV sources and solar light on the Earth's surface) the impact of the reversible photoproducts in the harmful biological effect decreases and other photoproducts are dominant. Assuming the photoinduced reactions (dimerisation and reversion) are statistical events, during the irradiation the chance for a number of nucleoprotein molecules to survive the radiation damage can be reality. The theoretical and experimental basis of these assumptions will be discussed in the case of bacteriophage T7 nucleoprotein.


Subject(s)
Bacteriophage T7/radiation effects , DNA, Viral/radiation effects , Exobiology , Models, Biological , Ultraviolet Rays , Bacteriophage T7/genetics , DNA Damage , Dose-Response Relationship, Radiation , Extraterrestrial Environment , Photochemistry , Vacuum
7.
Anal Chem ; 73(17): 4254-61, 2001 Sep 01.
Article in English | MEDLINE | ID: mdl-11569817

ABSTRACT

Micrometer-sized enzyme grids were fabricated on gold surfaces using a novel method based on a flow-through microdispenser. The method involves dispensing very small droplets of enzyme solution (approximately 100 pL) during the concomitant relative movement of a gold substrate with respect to the nozzle of a microdispenser, resulting in enzyme patterns with a line width of approximately 100 microm. Different immobilization methods have been evaluated, yielding either enzyme monolayers using functionalized self-assembled thiol monolayers for covalent binding of the enzyme or enzyme multilayers by cross-linking or entrapping the enzymes in a polymer film. The latter immobilization techniques allow the formation of coupled multienzyme structures. On the basis of this feature, coupled bienzyme (glucose oxidase and catalase) or three-enzyme (alpha-glucosidase, mutarotase, and glucose oxidase) microstructures consisting of line patterns of one enzyme intersecting with the patterned lines of the other enzyme(s) were fabricated. By means of scanning electrochemical microscopy (SECM) operated in the generator-collector mode, the enzyme microstructures and their integrity were visualized using the localized detection of enzymatically produced/consumed H2O2. A calibration curve for glucose could be obtained by subsequent SECM line scans over a glucose oxidase microstructure for increasing glucose concentrations, demonstrating the possibility of obtaining localized quantitative data from the prepared microstructures. Possible applications of these enzyme microstructures for multianalyte detection and interference elimination and for screening of different biosensor configurations are highlighted.


Subject(s)
Biosensing Techniques/instrumentation , Enzymes, Immobilized/chemistry , Gold , Proteins/chemistry
8.
Biosens Bioelectron ; 16(1-2): 17-21, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11261848

ABSTRACT

The polycrystalline uracil thin-layer dosimeter is a well-established method to monitor the biological effects of the environmental ultraviolet (UV) radiation. It is based on the optical density (OD) decrease of the uracil layer in the UV absorption band due to photodimerization of the crystal caused by UV irradiation. In the present study, we report measurements made with optical waveguide lightmode spectroscopy (OWLS) to characterize the changes in the optogeometrical parameters of the uracil layer caused by an artificial UV source. It is shown that UV irradiation causes a decrease in the refractive index and an increase of the optical anisotropy. The determined kinetic parameters of the UV dose-sensor response curves correlate well with results of OD measurements, but the sensitivity of OWLS is about ten times higher. The results show that OWLS is capable of analyzing the UV response of the uracil layer and opens the way for dosimetrical applications.


Subject(s)
Biosensing Techniques , Uracil/radiation effects , Spectrum Analysis/methods , Ultraviolet Rays , Uracil/chemistry
9.
Arq Bras Cardiol ; 74(5): 405-17, 2000 May.
Article in English, Portuguese | MEDLINE | ID: mdl-10951832

ABSTRACT

PURPOSE: To evaluate the efficacy of a systematic model of care for patients with chest pain and no ST segment elevation in the emergency room. METHODS: From 1003 patients submitted to an algorithm diagnostic investigation by probability of acute ischemic syndrome. We analyzed 600 ones with no elevation of ST segment, then enrolled to diagnostic routes of median (route 2) and low probability (route 3) to ischemic syndrome. RESULTS: In route 2 we found 17% acute myocardial infarction and 43% unstable angina, whereas in route 3 the rates were 2% and 7%, respectively. Patients with normal/non-specific ECG had 6% probability of AMI whereas in those with negative first CKMB it was 7%; the association of the 2 data only reduced it to 4%. In patients in route 2 the diagnosis of AMI could only be ruled out with serial CKMB measurement up to 9 hours, while in route 3 it could be done in up to 3 hours. Thus, sensitivity and negative predictive value of admission CKMB for AMI were 52% and 93%, respectively. About one-half of patients with unstable angina did not disclose objective ischemic changes on admission. CONCLUSION: The use of a systematic model of care in patients with chest pain offers the opportunity of hindering inappropriate release of patients with ACI and reduces unnecessary admissions. However some patients even with normal ECG should not be released based on a negative first CKMB. Serial measurement of CKMB up to 9 hours is necessary in patients with medium probability of AMI.


Subject(s)
Angina, Unstable/diagnosis , Chest Pain/etiology , Myocardial Infarction/diagnosis , Algorithms , Chest Pain/diagnosis , Electrocardiography , Emergency Medical Services , Humans , Predictive Value of Tests , Prospective Studies , Sensitivity and Specificity , Triage
10.
Arq Bras Cardiol ; 74(1): 13-29, 2000 Jan.
Article in English, Portuguese | MEDLINE | ID: mdl-10935289

ABSTRACT

OBJECTIVE: To evaluate the efficiency of a systematic diagnostic approach in patients with chest pain in the emergency room in relation to the diagnosis of acute coronary syndrome (ACS) and the rate of hospitalization in high-cost units. METHODS: One thousand and three consecutive patients with chest pain were screened according to a preestablished process of diagnostic investigation based on the pre-test probability of ACS determinate by chest pain type and ECG changes. RESULTS: Of the 1003 patients, 224 were immediately discharged home because of no suspicion of ACS (route 5) and 119 were immediately transferred to the coronary care united because of ST elevation or left bundle-branch block (LBBB) (route 1) (74% of these had a final diagnosis of acute myocardial infarction [AMI]). Of the 660 patients that remained in the emergency room under observation, 77 (12%) had AMI without ST segment elevation and 202 (31%) had unstable angina (UA). In route 2 (high probability of ACS) 17% of patients had AMI and 43% had UA, whereas in route 3 (low probability) 2% had AMI and 7% had UA. The admission ECG has been confirmed as a poor sensitivity test for the diagnosis of AMI (49%), with a positive predictive value considered only satisfactory (79%). CONCLUSION: A systematic diagnostic strategy, as used in this study, is essential in managing patients with chest pain in the emergency room in order to obtain high diagnostic accuracy, lower cost, and optimization of the use of coronary care unit beds.


Subject(s)
Cardiac Output, Low/diagnosis , Chest Pain/diagnosis , Emergency Service, Hospital , Aged , Angina, Unstable/diagnosis , Chest Pain/physiopathology , Costs and Cost Analysis , Diagnosis, Differential , Echocardiography , Electrocardiography , Emergency Service, Hospital/statistics & numerical data , Female , Humans , Length of Stay , Male , Middle Aged , Myocardial Infarction/diagnosis , Predictive Value of Tests , Sensitivity and Specificity
11.
Arq Bras Cardiol ; 74(1): 22-29, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10904277

ABSTRACT

OBJECTIVE: To evaluate the efficiency of a systematic diagnostic approach in patients with chest pain in the emergency room in relation to the diagnosis of acute coronary syndrome (ACS) and the rate of hospitalization in high-cost units. METHODS: One thousand and three consecutive patients with chest pain were screened according to a pre-established process of diagnostic investigation based on the pre-test probability of ACS determinate by chest pain type and ECG changes. RESULTS: Of the 1003 patients, 224 were immediately discharged home because of no suspicion of ACS (route 5) and 119 were immediately transferred to the coronary care united because of ST elevation or left bundle-branch block (LBBB) (route 1) (74% of these had a final diagnosis of acute myocardial infarction [AMI]). Of the 660 patients that remained in the emergency room under observation, 77 (12%) had AMI without ST segment elevation and 202 (31%) had unstable angina (UA). In route 2 (high probability of ACS) 17% of patients had AMI and 43% had UA, whereas in route 3 (low probability) 2% had AMI and 7 % had UA. The admission ECG has been confirmed as a poor sensitivity test for the diagnosis of AMI ( 49%), with a positive predictive value considered only satisfactory (79%). CONCLUSION: A systematic diagnostic strategy, as used in this study, is essential in managing patients with chest pain in the emergency room in order to obtain high diagnostic accuracy, lower cost, and optimization of the use of coronary care unit beds.

12.
Arq Bras Cardiol ; 74(1): 13-29, 2000 Jan.
Article in English, Portuguese | MEDLINE | ID: mdl-10904517

ABSTRACT

OBJECTIVE: To evaluate the efficiency of a systematic diagnostic approach in patients with chest pain in the emergency room in relation to the diagnosis of acute coronary syndrome (ACS) and the rate of hospitalization in high-cost units. METHODS: One thousand and three consecutive patients with chest pain were screened according to a pre-established process of diagnostic investigation based on the pre-test probability of ACS determinate by chest pain type and ECG changes. RESULTS: Of the 1003 patients, 224 were immediately discharged home because of no suspicion of ACS (route 5) and 119 were immediately transferred to the coronary care united because of ST elevation or left bundle-branch block (LBBB) (route 1) (74% of these had a final diagnosis of acute myocardial infarction [AMI]). Of the 660 patients that remained in the emergency room under observation, 77 (12%) had AMI without ST segment elevation and 202 (31%) had unstable angina (UA). In route 2 (high probability of ACS) 17% of patients had AMI and 43% had UA, whereas in route 3 (low probability) 2% had AMI and 7% had UA. The admission ECG has been confirmed as a poor sensitivity test for the diagnosis of AMI (49%), with a positive predictive value considered only satisfactory (79%). CONCLUSION: A systematic diagnostic strategy, as used in this study, is essential in managing patients with chest pain in the emergency room in order to obtain high diagnostic accuracy, lower cost, and optimization of the use of coronary care unit beds.

13.
Adv Space Res ; 26(12): 2021-8, 2000.
Article in English | MEDLINE | ID: mdl-12038488

ABSTRACT

As a consequence of the stratospheric ozone layer depletion biological systems can be damaged due to increased UV-B radiation. The aim of biological dosimetry is to establish a quantitative basis for the risk assessment of the biosphere. DNA is the most important target molecule of biological systems having special sensitivity against short wavelength components of the environmental radiation. Biological dosimeters are usually simple organisms, or components of them, modeling the cellular DNA. Phage T7 and polycrystalline uracil biological dosimeters have been developed and used in our laboratory for monitoring the environmental radiation in different radiation conditions (from the polar to equatorial regions). Comparisons with Robertson-Berger (RB) meter data, as well as with model calculation data weighted by the corresponding spectral sensitivities of the dosimeters are presented. Suggestion is given how to determine the trend of the increase in the biological risk due to ozone depletion.


Subject(s)
Bacteriophage T7/radiation effects , Radiation Monitoring/methods , Ultraviolet Rays , Uracil/radiation effects , DNA/radiation effects , DNA Damage , Germany , Greece , Hungary , Models, Biological , Nigeria , Ozone , Periodicity , Pyrimidine Dimers , Radiation Monitoring/instrumentation , Sunlight
14.
J Photochem Photobiol B ; 49(2-3): 171-6, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10392466

ABSTRACT

A procedure is presented for constructing the spectral sensitivity functions of biological dosimeters, using five polychromatic UV sources possessing different emission spectra. Phage T7 and uracil biological dosimeters have been used for measuring the dose rates of the lamps. Their spectral sensitivity functions consisting of two exponential terms have been constructed. The parameters of the spectral sensitivity functions have been determined by comparing the directly measured and calculated dose-rate values. The parameters of the sensitivity function are accepted as correct values when the deviation of the measured and calculated values is a minimum. Based on the deviations between the constructed and the experimentally determined spectral sensitivities with monochromatic sources, the differences between the measured and calculated results are interpreted. The importance of the correct spectral sensitivity data is demonstrated through the effectiveness spectra of a TL 01 lamp for phage T7 killing, uracil dimerization and erythema induction.


Subject(s)
Ultraviolet Rays , Bacteriophage T7/radiation effects , Calibration , Light , Radiometry/standards , Spectrophotometry, Ultraviolet , Uracil/radiation effects
15.
Photochem Photobiol ; 69(5): 545-52, 1999 May.
Article in English | MEDLINE | ID: mdl-10333760

ABSTRACT

Phage T7 can be used as a biological UV dosimeter. Its reading is proportional to the inactivation rate expressed in HT7 units. To understand the influence of phage proteins on the formation of DNA UV photoproducts, cyclobutane pyrimidine dimers (CPD) and (6-4)photoproducts ((6-4)PD) were determined in T7 DNA exposed to UV radiation under different conditions: intraphage T7 DNA, isolated T7 DNA and heated phage. To investigate the effects of various wavelengths, seven different UV sources have been used. The CPD and (6-4)PD were determined by lesion-specific antibodies in an immunodot-blot assay. Both photoproducts were HT7 dose-dependently produced in all three objects by every irradiation source in the biologically relevant UV dose range (1-10 HT7). The CPD to (6-4)PD ratios increased with the increasing effective wavelength of the irradiation source and were similar in intraphage T7 DNA, isolated DNA and heated phage with all irradiation sources. However, a significant decrease in the yield of both photoproducts was detected in isolated T7 DNA and in heated phage compared to intraphage DNA, the decrease was dependent on the irradiation source. Both photoproducts were affected the same way in isolated T7 DNA and heated phage, respectively. The yield of CPD and (6-4)PD was similar in B, C-like and A conformational states of isolated T7 DNA, indicating that the conformational switch in the DNA is not the decisive factor in photoproduct formation. The most likely explanation for modulation of photoproduct frequency in intraphage T7 DNA is that the presence of bound phage proteins induces an alteration in DNA structure that can result in an increased rate of dimerization and (6-4)PD production of adjacent based in intraphage T7 DNA.


Subject(s)
Bacteriophage T7/radiation effects , Deoxyribodipyrimidine Photo-Lyase/biosynthesis , Pyrimidine Dimers/biosynthesis , Viral Proteins/metabolism , Bacteriophage T7/genetics , Bacteriophage T7/metabolism , DNA, Viral/analysis , Deoxyribodipyrimidine Photo-Lyase/analysis , Pyrimidine Dimers/analysis , Ultraviolet Rays
16.
J Photochem Photobiol B ; 53(1-3): 20-5, 1999.
Article in English | MEDLINE | ID: mdl-10672525

ABSTRACT

To estimate the risk of enhanced UV-B radiation due to stratospheric ozone depletion, phage T7 and uracil thin-layer biological dosimeters have been developed, which weight the UV irradiance according to induced DNA damage. To study the molecular basis of the biological effects observed after UV irradiation, the spectral sensitivity curves of the two dosimeters and induction of the two major DNA photoproducts, cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts ((6-4)PDs), in phage T7 have been determined for polychromatic UV sources. CPDs and (6-4)PDs are determined by lesion-specific monoclonal antibodies in an immunodotblot assay. Phage T7 and uracil biological dosimeters together with a Robertson-Berger (RB) meter have been used for monitoring environmental radiation from the polar region to the equator. The biologically effective dose (BED) established with the three different dosimeters increases according to the changes in the solar angle and ozone column, but the degree of the change differs significantly. The results can be explained based on the different spectral sensitivities of the dosimeters. A possible method for determining the trend of the increase in the biological risk due to ozone depletion is suggested.


Subject(s)
Radiation Monitoring/methods , Sunlight , Ultraviolet Rays , Atmosphere/chemistry , Bacteriophage T7/radiation effects , DNA Damage/radiation effects , Health Status , Ozone/analysis , Pyrimidine Dimers/metabolism , Radiometry , Uracil
17.
J Photochem Photobiol B ; 53(1-3): 36-43, 1999.
Article in English | MEDLINE | ID: mdl-10672527

ABSTRACT

To determine the impact of environmental UV radiation, biological dosimeters that weight directly the incident UV components of sunlight have been developed, improved and evaluated in the frame of the BIODOS project. Four DNA-based biological dosimeters ((i) phage T7, (ii) uracil thin layer, (iii) spore dosimeter and (iv) DLR-biofilm) have been assessed from the viewpoint of their biological relevance, spectral response and quantification of their biological effectiveness. The biological dosimeters have been validated by comparing their readings with weighted spectroradiometer data, by comparison with other biological doses, as well as with the determined amounts of DNA UV photoproducts. The data presented here demonstrate that the biological dosimeters are potentially reliable field dosimeters for measuring the integrated biologically effective irradiance for DNA damage.


Subject(s)
Sunlight , Ultraviolet Rays/adverse effects , Bacillus subtilis/radiation effects , Bacteriophage T7/radiation effects , Biofilms/radiation effects , DNA Damage/radiation effects , Dose-Response Relationship, Radiation , Radiometry , Spores, Bacterial/drug effects , Uracil/radiation effects
18.
Photochem Photobiol ; 68(4): 527-31, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9796435

ABSTRACT

The correlation between the biologically effective dose (BED) of a phage T7 biological dosimeter and the induction of cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts ((6-4)PD) in the phage DNA was determined using seven various UV sources. The BED is the inactivation rate of phage T7 expressed in HT7 units. The CPD and (6-4)PD were determined by lesion-specific monoclonal antibodies in an immunodot-blot assay. The various lamps induced these lesions at different rates; the relative induction ratios of CPD to (6-4)PD increased with increasing effective wavelength of irradiation source. The amount of total adducts per phage was compared to the BED of phage T7 dosimeter, representing the average number of UV lesions in phage. For UVC (200-280 nm radiation) and unfiltered TL01 the number of total adducts approximates the reading; however, UV sources having longer effective wavelengths produced fewer CPD and (6-4)PD. A possible explanation is that although the most relevant lesions by UVC are the CPD and (6-4)PD, at longer wavelengths other photoproducts can contribute to the lethal damage of phages. The results emphasize the need to study the biological effects of solar radiation because the lesions responsible for the lethal effect may be different from those produced by various UV sources.


Subject(s)
Bacteriophage T7/radiation effects , DNA, Viral/radiation effects , Sunlight , Ultraviolet Rays , Bacteriophage T7/genetics , DNA, Viral/chemistry , Dose-Response Relationship, Radiation , Escherichia coli/virology , Pyrimidine Dimers/analysis
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