Analysis of the characteristics of the smash in padel: validation of the OASP instrument / Análisis de las características del remate en pádel: validación del instrumento OASP

The purpose of this study was to design and validate an observation instrument for the analysis of the performance parameters related to the smash in padel. Eleven experts, who had to meet four of the five inclusion criteria, participated in the process. Aiken's V coefficient and confidence intervals were used to calculate content validity and Cronbach's α coefficient to analyze reliability. The adequacy and writing of the eighteen items initially designed were evaluated. Four variables were eliminated due to obtaining values ​​<.87 in Aiken's V coefficient for adequacy. The rest of the variables were modified in their wording, according to the qualitative evaluations of the experts, or were considered correct. The reliability of the instrument was acceptable, (α=.82). The OASP instrument is very new, as it is of interest for analyzing the use and effectiveness of the padel smash. (AU)

El propósito de este estudio fue diseñar y validar un instrumento de observación para el análisis de las características del remate relacionadas con el rendimiento en pádel. En el proceso participaron once expertos, los cuales debían cumplir cuatro de los cinco criterios de inclusión. El coeficiente V de Aikene intervalos de confianza se utilizaron para calcular la validez de contenido y el coeficiente 𝛼de Cronbach para analizar la fiabilidad. Se evaluó la adecuación y redacción de los dieciocho ítems diseñados inicialmente. Se eliminaron cuatro variables por obtener valores <.87 en el coeficiente V de Aikenen la adecuación. El resto de las variables fueron modificadas en su redacción, según las valoraciones cualitativas de los expertos, o se consideraron correctas. La fiabilidad del instrumento fue aceptable, (𝛼=.82). El instrumento OASP es muy novedoso, pues resulta de interés para analizar el uso y la eficacia del remate en pádel. (AU)

Validación de dos programas de intervención para la enseñanza del fútbol escolar / Validation of Two Intervention Programs for Teaching School Soccer

El propósito del estudio fue validar dos programas de intervención, correspondientes a dos unidades didácticas realizadas cada una en base a dos metodologías diferentes: Direct Instruction (ID) y Tactical Games Approach (TGA), para la enseñanza del fútbol escolar. Se diseñaron dos programas de intervención semejantes con el mismo número de tareas, sesiones, fases de juego, contenidos y objetivos. En el proceso de validación participaron 13 jueces expertos. La validez de contenido se calculó mediante el coeficiente de V de Aiken y sus intervalos de confianza. Para la consistencia interna se empleó el coeficiente de α de Cronbach. Ninguna de las tareas que componen los programas de intervención fue eliminada al superar el valor crítico exacto (V ≥ .69). La consistencia interna de las tareas fue excelente (alfa = .97). Por tanto, ambos programas de intervención son válidos y fiables para la enseñanza del fútbol escolar, así como para comparar los efectos de ambas metodologías

The purpose of this study was to validate two intervention programs, corresponding to two didactic units, based in two different methodologies: Direct Instruction (DI) and Tactical Games Approach (TGA), for teaching school soccer. These two intervention programs were similar, with the same number of tasks, sessions, phases of play, specific contents and objectives. In the validation process participated 13 expert judges. Content validity was calculated by the coefficient of Aiken’s V and its confidence intervals. Also, internal consistency was calculated using Cronbach’s α. None of the 29 tasks of each intervention program was eliminated because they obtained values higher than the exact critical value (V ≥ .69). The internal consistency of the tasks, that formed both intervention programs together, was excellent (alpha = .97). For these reasons, both intervention programs are valid and reliable for teaching school soccer, as well as to compare the effects of these teaching methodologies

Revisión sistemática de la eficacia del tratamiento combinado de fisioterapia junto con toxina botulínica tipo A en la espasticidad de miembros inferiores en niños con parálisis cerebral / Systematic review of the effectiveness of physiotherapy plus type A botulimun toxin in reducing lower limb spasticity in children with cerebral palsy

Introducción: la parálisis cerebral es una lesión no progresiva del sistema nervioso central que origina, entre otros posibles síntomas, un tono muscular patológico. La espasticidad es muy frecuente y conlleva limitaciones en las actividades de la vida diaria. Aunque existen multitud de tratamientos físicos y farmacológicos para este alterado tono muscular, su eficacia está muy discutida, ya que los resultados son muy dispares de un individuo a otro. Objetivo: el objetivo del trabajo es realizar una revisión sistemática de la eficacia del tratamiento de la espasticidad de miembros inferiores, en cualquier tipo de parálisis cerebral infantil, mediante tratamiento fisioterápico junto con tratamiento farmacológico con toxina botulínica tipo A. Dicha eficacia se refiere a conseguir un aumento en el rango articular, una disminución en el tono muscular o una mejoría en la marcha, que se reflejarán en escalas de valoración específicas y en escalas de valoración de las actividades de la vida diaria. Los objetivos secundarios del trabajo son conocer los efectos adversos de la inyección de la toxina y la variabilidad de la duración de los efectos de esta. Material y método: se realizó una búsqueda bibliográfica de artículos desde enero de 2006 hasta enero de 2013, ambos incluidos, en las siguientes bases de datos: Biblioteca Cochrane, Medline, CINAHL, ISI Web of Knowledge y PEDro. Se valoró la calidad de los estudios prospectivos y retrospectivos y de los ensayos clínicos con la Escala de Jadad (también llamada Sistema de Puntuación de Calidad de Oxford), y la de las revisiones sistemáticas con la Assessment of Multiple Systematic Reviews (herramienta de valoración de revisiones sistemáticas). Resultados: se encontraron 14 artículos que cumplían los criterios de inclusión. Se observó, en 9 de ellos, una disminución en el tono muscular, un aumento del rango articular y una mejora en la función motora gruesa. Dichos resultados variaron de unos pacientes a otros debido, entre otras causas, a la edad (mejores resultados en pacientes menores de 6 años), la musculatura inyectada (mejores resultados en el tríceps sural), el uso de ecografía como guía para una mayor precisión de la inyección o el estado cognitivo del paciente. Discusión: se observaron resultados estadísticamente significativos en la reducción del tono muscular a corto plazo en 12 de los estudios, detectándose el momento de mayor disminución aproximadamente a las 4-5 semanas postinyección. Sin embargo, a largo plazo (un año) solo en un estudio se mantenía esta disminución del tono muscular. El uso de multitud de escalas obstaculizó la posibilidad de comparar los resultados de la medición del tono muscular o la valoración de la función motora gruesa entre diferentes estudios. Por otro lado, algunos artículos dejan en un segundo plano las técnicas de rehabilitación utilizadas, su frecuencia y sus efectos, lo que ha dificultado saber en qué medida condicionaron la eficacia de la toxina. El tratamiento ortopédico se incluyó en 8 estudios y sus resultados coinciden en una ganancia mayor en la dorsiflexión de tobillo y en la función motora gruesa. La edad para comenzar el tratamiento con la toxina para que esta sea más eficaz está muy discutida: hay 5 estudios en los que se afirma que los menores de 6 años obtuvieron mejores resultados en la disminución del tono muscular, mientras que en otro estudio se asegura que la edad no es un factor concluyente. Para estudios futuros es importante incorporar el uso del ecógrafo durante la inyección, explicar las técnicas de rehabilitación aplicadas y su frecuencia, mejorar la calidad de los estudios con muestras de mayor tamaño y más homogéneas y utilizar las escalas más actualizadas y aceptadas. Conclusiones: el tratamiento combinado de fisioterapia y toxina botulínica tipo A disminuye el tono muscular, aumenta el rango articular de movimiento y mejora la función motora gruesa, lo que incluye mejoras en las transferencias y en la marcha, especialmente si se añade tratamiento ortopédico. Los pacientes presentaron tras la inyección un pico de mejora respecto al tono muscular aproximadamente al mes; sin embargo, dicho pico no se mantenía a largo plazo (un año), surgiendo de nuevo el tono patológico

Introduction: cerebral palsy is the result of non-progressive damage to the central nervous system and causes, among other possible symptoms, pathological muscle tone. Spasticity is very common and leads to limitations in activities of daily living. There are many physical and drug therapies for this altered muscle tone but their effectiveness is widely debated because the results are very different from one individual to another. Objective: the objective of this study was to conduct a systematic review of the effectiveness of treatment of lower limb spasticity in any type of cerebral palsy, using physiotherapeutic and drug treatment with type A botulinum toxin. This effectiveness refers to the achievement of an increase in joint range, a decrease in muscle tone or an improvement in gait that will be reflected in specific rating scales and assessment of scales of activities of daily living. Secondary objectives were to determine the adverse effects of botulinum toxin injection and variability in the duration of its effects. Material and method: a literature search was conducted of studies published from January 2006 to January 2013, inclusive, in the following databases: Cochrane Library, Medline, CINAHL, ISI Web of Knowledge and PEDro. The quality of the clinical trials as well as those of the prospective and retrospective studies was evaluated by the Jadad Scale (also known as the Oxford Quality Scale) and by the Assessment of Multiple Systematic Reviews measurement tool. Results: fourteen articles met the inclusion criteria. Nine of these studies observed a decrease in muscle tone, an increase in joint range and an improvement in gross motor function. These results varied from one patient to another due to age (better results in patients younger than 6 years old), injected muscles (better results in the sural triceps), use of ultrasound-guided injection for greater injection accuracy, and the patient's cognitive status. Discussion: statistically significant results were found in the short-term decrease of spasticity in 12 studies, the best moment being detected approximately between the 4th and 5th week after the injection. However, only one study reported that this decrease in muscle tone was maintained in the long term (one year). The use of a large number of different scales hampered comparison of the results of muscle tone measurement or gross motor function assessment in distinct studies. Some articles did not describe the frequency and effects of the implemented rehabilitation programme and therefore it was difficult to determine the extent of the influence of these factors on the effectiveness of botulinum toxin. Orthopaedic treatment was included in 8 studies, obtaining better results in ankle dorsiflexion and in gross motor function. There is wide debate on when botulinum toxin injections should be started to achieve maximal effectiveness; 5 studies claim better results in decreased muscle tone in children younger than 6 years, whereas another study asserts that age is not a conclusive factor. Future studies should incorporate the use of ultrasound during injection, explain the rehabilitation techniques applied and their frequency, include larger and more homogeneous samples to improve quality, and use the most updated and widely accepted scales. Conclusions: combined treatment with physiotherapy and type A botulinum toxin reduces muscle tone, increases joint range of motion and improves gross motor function, which includes enhanced transfers and gait, especially if orthopaedic treatment is added. Patients showed a peak improvement in muscle tone at approximately one month after the injection. However, this improvement was not maintained in the long term, with pathological muscle tone developing once again

Análisis del proceso formativo en jugadores expertos: validación de instrumento / Analysis of expert players’ training process: validation of tools

El objetivo del presente estudio fue la creación y validación de una batería de instrumentos de medición (ATPEP), compuesta por dos entrevistas y una escala, para identificar y analizar el proceso de formación en jugadores expertos de deportes colectivos. La batería de instrumentos se ha elaborado siguiendo un procedimiento ecléctico (inductivo y deductivo). En el proceso de validación se utilizó el peritaje de expertos con 11 jueces, calculando la validez de contenido mediante la obtención del coeficiente Vde Aiken. Las dimensiones abordadas en las entrevista y en la escala fueron: contexto social, contexto deportivo, habilidades interindividuales, habilidades intraindividuales, táctica, técnica, condición física y antropometría. Solamente 2 de los 132 ítems evaluados obtuvieron valores de V lo suficientemente bajos como para ser eliminados. La propuesta final de la batería de instrumentos ATPEP se ha elaborado teniendo en cuenta las valoraciones cualitativas y cuantitativas de los expertos (AU)

The aim of this study was to create and validate a string of measurement tools (ATPEP), composed of two interviews and one scale, in order to identify and analyze expert team players’ training process. This string of tools has been elaborated using an eclectic procedure (inductive and deductive).11 experts judges led the validation process, and calculating content validity by obtaining Aiken´s V coefficient. The discussed dimensions in both the interviews and the scale were the following: social context, sport context, inter-individual abilities, intra-individual abilities, tactic, technique, fitness and anthropometry. Only 2 out of the 132 evaluated items obtained V values low enough to be removed. Finally, the ATPEP battery instruments were elaborated taking into account quantitative and qualitative experts’ assessments (AU)

Biotinidase knockout mice show cellular energy deficit and altered carbon metabolism gene expression similar to that of nutritional biotin deprivation: clues for the pathogenesis in the human inherited disorder.

Biotin is the prosthetic group of carboxylases that have important roles in the metabolism of glucose, fatty acids and amino acids. Biotinidase has a key role in the reutilization of the biotin, catalyzing the hydrolysis of biocytin (ε-N-biotinyl-l-lysine) and biocytin-containing peptides derived from carboxylase turnover, thus contributing substantially to the bioavailability of this vitamin. Deficient activity of biotinidase causes late-onset multiple carboxylase in humans, whose pathogenic mechanisms are poorly understood. Here we show that a knock-out biotinidase-deficient mouse from a C57BL/6 background that was fed a low biotin diet develops severe ATP deficit with activation of the energy sensor adenosine monophosphate (AMP)-activated protein kinase (AMPK), inhibition of the signaling protein mTOR, driver of protein synthesis and growth, and affecting the expression of central-carbon metabolism genes. In addition, sensitivity to insulin is augmented. These changes are similar to those observed in nutritionally biotin-starved rats. These findings further our understanding of the pathogenesis of human biotinidase deficiency.

Sarcoidosis as a diagnostic pitfall of pancreatic cancer

Sarcoidosis (SA) is accompanied by malignancy more than can be explained by chance. Cancer can occur in patients with an established diagnosis of SA and SA can subsequently develop in a cancer patient. Malignancy can also be associated with the occurrence of sarcoid reactions (SR), which are typically restricted to the regional lymph nodes. Problems may also arise in distinguishing between tumour-related SRs and true systemic SA. Here we present a case with both SA and pancreatic cancer, and we discuss the result of distinguishing between SA and SRs in a patient with concurrent cancer (AU)

Analysis of 31 CFTR mutations in 55 families from the South of Spain.

We carried out a molecular analysis of 350 chromosomes from 55 families originating from the South of Spain (Andalucia) who were diagnosed with cystic fibrosis (CF). We used polymerase chain reaction, followed by an oligonucleotide ligation assay (OLA) and sequence-coded separation using capillary electrophoresis. A frequency of 43.5% for DeltaF508 was found, making it the most common CF mutation in our sample. Seven more mutations (G542X, R334W, R1162X, 2789+5G-->A, R117H, DeltaI507 and W1282X) were detected and accounted for 24.7% of the total. The remaining mutations (31.8%) were undetectable with the methodology used in this study.

[Male with sudden-onset dementia associated with long lasting diarrhea as manifestations of Whipple's disease]. / Varón con demencia de aparición brusca, asociada a diarrea de larga evolución como manifestaciones de la enfermedad de Whipple.

A case of a 55-year old male with Whipple's disease who consulted for dementia (aggressivity, memory loss of recent events, sleep rhythm disturbances) is presented. Furthermore, the patient had referred changes in intestinal movement four years beforehand in addition to erratic arthralgias. Response to treatment (trimethoprim-sulfamethoxazole for one year) was favorable with resolution of both the neurologic and gastrointestinal pictures. The radiologic alterations of this entity are reviewed and suggest that this disease should be considered as a cause of dementia.

Metoclopramide enhances the effect of photodynamic therapy on xenografted human squamous cell carcinoma of the head and neck.

OBJECTIVE: Photodynamic therapy (PDT) is a promising new treatment modality for head and neck cancer that is based on the uptake of a systemically administered photosensitizer in tumor tissue and local illumination of the lesion by a high-intensity visible light source, typically a tunable argon-pumped dye laser. We developed a new photosensitizer named silicon phthalocyanine [SiPc(OH) OSi(CH3)2(CH2)3N(CH3)2, abbreviated as SiPc IV], which yields superior PDT responses in vitro and in vivo compared with other clinically used photosensitizers. However, tumor regrowth following SiPc IV-based PDT is still a therapeutic problem. The benzamide derivatives, for example, have been shown to enhance tumor ablation when used during radiotherapy and chemotherapy. Therefore, we used metoclopramide hydrochloride, a benzamide derivative, to evaluate its effects on PDT response. DESIGN: Intradermally injected human squamous cell carcinoma cells were grown to 40 to 80 mm3 in athymic nude mice and irradiated with 675-nm light (75 J/cm2, 75 mW/cm2) 24 hours after the intraperitoneal injection of SiPc IV (1.0 mg/kg). Metoclopramide hydrochloride (2 to 48 mg/kg) was injected intraperitoneally 1 hour before and 24 and 48 hours after irradiation. RESULTS: Tumors exposed to PDT alone showed 80% to 90% tumor regression with regrowth in most animals within 20 days. Tumors treated with metoclopramide hydrochloride (48 mg/kg) plus PDT demonstrated 100% tumor regression without regrowth up to the time of killing (150 days). No observable toxic effects were clinically apparent with the high doses of metoclopramide. CONCLUSIONS: Our results show that administering metoclopramide in combination with PDT may be a promising approach to the management of head and neck cancer.

New phthalocyanine photosensitizers for photodynamic therapy.

Six new aluminum and silicon phthalocyanines have been synthesized and their photocytotoxicity toward V79 cells has been studied. The compounds that have been prepared are: A1PcOSi(CH3)2(CH2)3N(CH3)2, I; A1Pc-OSi(CH3)2(CH2)3N(CH3)3+I-, II; CH3SiPcOSi(CH3)2(CH2)3N(CH3)2, III; HOSiPcOSi(CH3)2(CH2)3N(CH3)2, IV; HOSiPcOSi(CH3)2(CH2)3N(CH3)3+I-, V; and SiPc[OSi(CH3)2(CH2)3N(CH3)3+I-]2, VI. Relative growth delay values for compounds I-VI and relative cytotoxicity values for compounds I, II, IV, V and VI have been determined. Compounds I and II have been shown to be comparable in photocytotoxicity to what is presumed to be A1PcOH.xH2O, and compound IV has been shown to have greater activity. The classes of compounds to which these six compounds belong appear to have potential for photodynamic therapy.

Protection by the fluoride ion against phthalocyanine-induced photodynamic killing of Chinese hamster cells.

When a dilute F- solution was added to a culture of Chinese hamster cells that had been preincubated with an aluminium phthalocyanine sensitizer derived from AlPcCl, the photosensitivity of the cells was markedly reduced compared to control cells not treated with F-. Under the same treatment conditions, the reduction in [3H]thymidine incorporation into cellular DNA caused by light and this sensitizer and the production of DNA-protein crosslinks caused by light and this sensitizer were also inhibited by F-. In contrast, the killing of Chinese hamster cells, the reduction of thymidine incorporation by the cells, and the production of DNA-protein crosslinks in the cells caused by the combination of light and either Photofrin II or the silicon phthalocyanine HOSiPcOSi(CH3)2(CH2)3-N(CH3)2 were not inhibited by F-. We conclude that the aluminium phthalocyanine sensitizer used is largely or completely AlPc(OH)(H2O), that it is converted to a fluoro complex by F-, and that this compound probably is a less efficient generator of photochemical damage at a critical cellular target(s) than is AlPc(OH)(H2O). The inhibition of thymidine incorporation and DNA-protein crosslink formation indicates that the effects of F- can be expressed at intracellular sites. It is further concluded that the silicon phthalocyanine sensitizer and Photofrin II do not interact significantly with F-.

Photofrin II photosensitization is mutagenic at the tk locus in mouse L5178Y cells.

Photosensitization mediated by Photofrin II (PFII) was found to be mutagenic at the heterozygous thymidine kinase (tk) locus in mouse L5178Y lymphoma strains LY-S1 and LY-R16 but not in strain LY-R83 which is hemizygous at the tk locus. After treatments yielding 37% survival, the mutagenicity of photosensitization with PFII in strain LY-S1 was similar to that of other mutagenic agents including x-radiation, ethyl methanesulfonate, and photosensitization with chloroaluminum phthalocyanine (AlPcCl). Although both strain LY-S1 and strain LY-R16 were mutagenized by photosensitization with PFII, only strain LY-S1 was mutagenized by photosensitization with AlPcCl. The non-mutability of strain LY-R83 following photodynamic treatment with either sensitizer may be because of the poor recovery of mutants with intergenic mutations in this TK+/0 hemizygous strain, whereas the non-mutability of strain LY-R16 subjected to photodynamic treatment with AlPcCl may be because LY-R16 cells sustaining mutagenic damage do not survive for reasons other than the loss of an essential gene.

Photodynamic therapy induces rapid cell death by apoptosis in L5178Y mouse lymphoma cells.

The mode of cell death of two strains of mouse lymphoma L5178Y cells was studied following photodynamic therapy (PDT) sensitized by chloroaluminum phthalocyanine. Strains LY-R and LY-S differ in their relative sensitivities to UVC radiation, X-radiation, and PDT; both responded to PDT by undergoing apoptosis. The DNA was degraded into fragments with lengths which are multiples of approximately 180-190 base pairs (i.e., oligonucleosome size), a biochemical marker of apoptosis. The DNA fragmentation was dose and time dependent which indicates this response to be an enzymic process related to cell killing. Cycloheximide, a protein synthesis inhibitor, and actinomycin D, an RNA synthesis inhibitor, enhanced the endonucleolytic DNA fragmentation. Transmission electron microscopy revealed chromatin condensation around the periphery of the nucleus, which is also characteristic of apoptosis. The induction of apoptosis in L5178Y cells by PDT was rapid, with marked degradation of DNA occurring in as little as 30 min. The rapidity of the response to PDT suggests that cellular damage produced by PDT can directly activate endonucleolysis and chromatin condensation, thereby by-passing many of the early steps in the signal transduction program which are acted upon by other agents causing apoptosis.

Basic radiobiological investigations of fast neutrons.

The radiobiological properties of a cyclotron-produced 43-MeV (p----Be) fast-neutron beam relative to gamma rays have been investigated using Chinese hamster V79 cells in culture. As expected, the relative biological effectiveness (RBE) of this neutron beam for cell killing was shown to increase as dose decreased, and the effectiveness per unit dose was slightly less compared to a 25-MeV (d----Be) neutron beam. By tracing single cells that formed microcolonies after irradiation, we found cell proliferation kinetics to be retarded to a greater extent by fast neutrons than by gamma irradiation. Following either neutron or gamma irradiation, a fraction of the irradiated cells failed to divide in the first postirradiation division and another fraction could produce as many as four generations of progeny before proliferation stopped. The properties of these cells presumed to be destined for death suggest that more than one mechanism and/or multistep process underlies the radiation-induced proliferative death. The fast-neutron beam was also found to be more effective quantitatively than gamma rays in producing DNA double-strand breaks (DSBs, measured by nondenaturing filter elution), and G1-phase chromosome fragments (measured by the premature chromosome condensation technique). However, the reverse was observed for DNA single-strand breaks (SSBs, measured by alkaline filter elution or hydroxylapatite uncoiling). Interestingly, both fast neutrons and gamma rays produced a large component of SSBs and DSBs with a fast-rejoining time constant of about 2-5 min, which appears to be independent of dose. The latter results could not resolve the possibility of lengthening the repair-time constant by increasing radiation dose within the range that is reflected by the shoulder of the survival curve, and consequently did not support the idea of repair saturation as a mechanism for the presence of the shoulder. The RBE for the hypoxanthine phosphoribosyl transferase mutation frequency per survivor at the 10% survival level was estimated to be 2.5, a value that is comparable to the RBE (2.1) for cell killing at the same survival level. Although most of the above-mentioned findings are compatible qualitatively with the relatively high-LET (linear energy transfer) nature associated with the fast-neutron beam, the significance of the action attributable to the mixture of LET could not be delineated in these experiments. Further, the biological significance of DSBs and chromosome aberration and the molecular mechanisms responsible for the repair and expression of these damaging processes remain to be elucidated.

Local-regional breast cancer recurrence following mastectomy.

Local-regional recurrence patterns were investigated in 1392 patients with breast cancer. Primary treatment for all patients included a mastectomy. Nine hundred seventeen patients had negative nodes and did not receive systemic therapy. Four hundred seventy-five patients had node metastases and were randomized to receive different combinations of chemoendocrine therapy. Follow-up ranged between 5 and 16 years. Two hundred thirty (25.8%) node-negative patients have had recurrences, with the initial recurrence being local-regional in 9.2%. Two hundred forty-two (50.9%) node-positive patients have had recurrences, with the initial recurrence being local-regional in 17.1%. Larger tumors and more extensive node involvement were associated with more first local-regional recurrences. The relative percent of first local-regional recurrence among patients in whom cancer recurred was similar for node-negative and node-positive patients (35.4% and 33.5%, respectively). In 63.6% of patients in whom cancer recurred, first local-regional recurrence were distant. Larger tumors, more extensive node involvement, and a shorter disease-free interval after mastectomy were associated with more rapid appearance of distant recurrence among these patients.

Post-treatment interactions of photodynamic and radiation-induced cytotoxic lesions.

The interaction of chloroaluminum phthalocyanine-sensitized photodynamic treatment and gamma-irradiation was studied in confluent murine L929 fibroblasts. When the cells were given the combined treatments and immediately subcultured for determination of cell survival by colony formation, the data indicate independent actions of each modality. However, when subculture was delayed for 1 h, a substantial fraction of cells treated with a sub-lethal dose of PDT followed by 5 Gy gamma-radiation detached from the monolayer. Most of these detached cells were no longer clonogenic. The mode of photosensitized cell killing was found to be different from that of ionizing radiation-induced cell killing. Photosensitized cell killing was accompanied by morphological changes in the cells and extensive DNA degradation within one hour following the treatment. When chloroaluminum phthalocyanine pretreated cells were exposed to a sublethal fluence of light (6 kJ/m2) and a lethal dose of gamma-radiation (5 Gy), DNA degradation was enhanced, and about 20% of the cell population appeared to undergo the type of cell death typical of photodynamic treatment. Thus, although different initial lethal lesions are induced by photodynamic treatment and by ionizing radiation, interactions may occur during processing of the damage.

Enhancement of photodynamic cell killing (with chloroaluminum phthalocyanine) by treatment of V79 cells with the ionophore nigericin.

The K+/H+ ionophore nigericin dramatically increases killing of V79 cells by photodynamic therapy (PDT), when cells pretreated with 1 microM chloroaluminum phthalocyanine are incubated with nigericin before exposure to red light. Nigericin affects primarily the shoulder of the PDT dose-response curve, reducing the surviving fraction from 0.90 to 0.02 after a fluence of 7 kJ/m2 and from 0.80 to 0.0003 after a fluence of 12 kJ/m2. Optimal enhancement of PDT occurs when cells are incubated with 2 microM nigericin, at pHe 6.7, for 30 to 60 min before irradiation. However, significant enhancement of PDT also occurs when nigericin is added immediately before irradiation. Treatments with chloroaluminum phthalocyanine and nigericin, nigericin alone, or nigericin and red light are not toxic to cells. Cells treated with the combined agents display a rounded morphology 2 h after light exposure and lyse within 12 h. However, rounding of cells is not accompanied by severe depletion of ATP or by permeabilization of the plasma membrane to trypan blue. These results, together with known metabolic effects of nigericin, suggest that nigericin potentiates PDT by perturbing ion transport across either mitochondrial or plasma membranes.

DNA lesions and DNA degradation in mouse lymphoma L5178Y cells after photodynamic treatment sensitized by chloroaluminum phthalocyanine.

Two closely related strains of mouse lymphoma L5178Y cells, LY-R and LY-S, have been found to differ in their sensitivity to the cytotoxic effects of photodynamic treatment (PDT) with chloroaluminum phthalocyanine (CAPC) and red light. Strain LY-R is more sensitive to photodynamic cell killing than strain LY-S. Differences in uptake of CAPC could not account for the differences in cytotoxic effects. There was no marked difference between the two strains in the induction of single-strand breaks (which includes frank single-strand breaks and alkali-labile lesions), but substantially more DNA-protein cross-links were formed in strain LY-R by CAPC and light. Repair of single-strand breaks proceeded with similar kinetics in both strains for the first 30 min post-irradiation, suggesting that these lesions are not responsible for the differential sensitivity of the two strains to the lethal effects of photodynamic treatment. Thereafter, alkaline elution revealed the presence of increasing DNA strand breakage in strain LY-R. DNA degradation, as measured by the conversion of prelabeled [14C] DNA to acid-soluble radioactivity, was more rapid and extensive in strain LY-R.