Evaluation of the combined effects of hyperthermia, cobalt-60 gamma rays and IUdR on cultured glioblastoma spheroid cells and dosimetry using TLD-100

In radiation treatment, the irradiation which is effective enough to control the tumors far exceeds normal-tissues tolerance. Thus to avoid such unfavourable outcomes, some methods sensitizing the tumor cells to radiation are used. Iododeoxyuridine [IUdR] is a halogenated thymidine analogue that known to be effective as a radiosensitizer in human cancer therapy. Improving the potential efficacy of radiation therapy after combining to hyperthermia depends on the magnitude of the differential sensitization of the hyperthermic effects or on the differential cytotoxicity of the radiation effects on the tumor cells. In this study, we evaluated the combined effects of IUdR, hyperthermia and gamma rays of 60Co on human glioblastoma spheroids culture. In this experimental study,the cultured spheroids with 100microm diameter were treated by 1 microM IUdR, 43°C hyperthermia for an hour and 2 Gy gamma rays, respectively. The DNA damages induced in cells were compared using alkaline comet assay method, and dosimetry was then performed by TLD-100. Comet scores were calculated as mean +/- standard error of mean [SEM] using one-way ANOVA. Comparison of DNA damages induced by IUdR and hyperthermia + gamma treatment showed 2.67- and 1.92-fold enhancement, respectively, as compared to the damages induced by radiation alone or radiation combined IUdR. Dosimetry results showed the accurate dose delivered to cells. Analysis of the comet tail moments of spheroids showed that the radiation treatments combined with hyperthermia and IUdR caused significant radiosensitization when compared to related results of irradiation alone or of irradiation with IUdR. These results suggest a potential clinical advantage of combining radiation with hyperthermia and indicate effectiveness of hyperthermia treatment in inducing cytotoxicity of tumor cells

Polymorphisms of Aspirin-Metabolizing Enzymes CYP2C9, NAT2 and UGT1A6 in Aspirin-Intolerant Urticaria

Acetyl salicylic acid (ASA) is metabolized by UDP-glucuronosyltransferase 1A6 (UGT1A6), cytochrome P4502C9 (CYP2C9), and N-acetyl transferase 2 (NAT2). Variations in the activities of these enzymes may modulate adverse ASA-related symptoms such as urticaria. We examined whether polymorphisms in the UGT1A6, CYP2C9, and NAT2 genes are related to ASA-intolerant urticaria (AIU). The genotypes of 148 subjects with AIU (AIU group) and 260 normal healthy control subjects (NC group) were analyzed with respect to the following single nucleotide polymorphisms: CYP2C9 -1188T>C and CYP2C9*3A1075C; UGT1A6 T181A A>G and UGT1A6 R184S A>C; and NAT2 9796A>T, NAT2 197G>A, NAT2 286G>A, NAT2 9601A>G, and NAT2 9306A>G. There were significant differences in the allele frequencies for the CYP2C9 polymorphisms between the two groups. The frequency of the minor allele CYP2C9 -1188T>C was significantly higher in the AIU group than in the NC group (P=0.005). The frequency of the variant genotype CC was higher in the AIU group compared with the controls in both the co-dominant (P=0.007) and recessive models (P=0.012). The frequency of haplotype 2 [CA] was also significantly higher in the AIU group in both the co-dominant (P=0.006) and dominant models (P=0.012). There was no significant difference in genotype frequencies for any of the UGT1A6 or NAT2 polymorphisms between the two groups. Clinical parameters did not differ according to genotype. These results suggest that the C allele of CYP2C9 -1188T>C may be associated with AIU.

Evaluation of combination effects of 2- methoxyestradiol and methoxyamine on IUdRinduced radiosensitization in glioma spheroids

Glioblastoma is the most common and most malignant cancer of central nervous system. Targeted radiotherapy is an effective method toward its treatment. Iododeoxyuridine [IUdR] is a halogenated thymidine analogue known to be effective as a radiosensitizer in human cancer therapy. In this study we have evaluated the combination effects of 2-Methoxyestradiol, an inhibitor of hypoxia inducible factor 1 alpha [HIF-1 alpha] and Methoxyaminem, an inhibitor of base excision repair [BER] pathway on radiosensitization of IUdR in glioblastoma spheroid culture. The cytotoxic damages of DNA in U87MG cell line were compared using colony formation assay. Experiments were performed in large spheroids with a diameter of approximately 350micro m. Evaluation of the effects of IUdR with 2ME2 and MX pretreatment on spheroid cultured cell followed by ionizing irradiation showed more enhancemented [p

Imaging of Herpes Simplex Virus Type 1 Thymidine Kinase Gene Expression with Radiolabeled 5-(2-iodovinyl)-2'-deoxyuridine (IVDU) in Liver by Hydrodynamic-based Procedure / 핵의학분자영상

PURPOSE: Hydrodynamic-based procedure is a simple and effective gene delivery method to lead a high gene expression in liver tissue. Non-invasive imaging reporter gene system has been used widely with herpes simplex virus type 1 thymidine kinase (HSV1-tk) and its various substrates. In the present study, we investigated to image the expression of HSV1-tk gene with 5-(2-iodovinyl)-2'-deoxyuridine (IVDU) in mouse liver by the hydrodynamicbased procedure. MATERIALS AND METHODS: HSV1-tk or enhanced green fluorescence protein (EGFP) encoded plasmid DNA was transferred into the mouse liver by hydrodynaminc injection. At 24 h post-injection, RT-PCR, biodistribution, fluorescence imaging, nuclear imaging and digital wholebody autoradiography (DWBA) were performed to confirm transferred gene expression. RESULTS: In RT-PCR assay using mRNA from the mouse liver, specific bands of HSV1-tk and EGFP gene were observed in HSV1-tk and EGFP expressing plasmid injected mouse, respectively. Higher uptake of radiolabeled IVDU was exhibited in liver of HSV1-tk gene transferred mouse by biodistribution study. In fluorescence imaging, the liver showed specific fluorescence signal in EGFP gene transferred mouse. Gamma-camera image and DWBA results showed that radiolabeled IVDU was accumulated in the liver of HSV1-tk gene transferred mouse. CONCLUSION: In this study, hydrodynamic-based procedure was effective in liver-specific gene delivery and it could be quantified with molecular imaging methods. Therefore, co-expression of HSV1-tk reporter gene and target gene by hydrodynamic-based procedure is expected to be a useful method for the evaluation of the target gene expression level with radiolabeled IVDU.

The Synthesis of the Stable IVDU Derivative for Imaging HSV-1 TK Expression / 핵의학분자영상

PURPOSE: 5-iododeoxyuridine analogues have been exclusively developed for the potential antiviral and antitumor therapeutic agents. In this study, we synthesized carbocyclic radioiododeoxyuridineanalogue (ddIVDU) and carbocyclic intermediate as efficient carbocyclic radiopharmaceuticals. MATERIALS AND METHODS: The synthesis is LAH reduction, hetero Diels-Alder reaction as key reactions including Pd(0)-catalyzed coupling reaction together with organotin. MCA-RH7777 (MCA) and MCA-tk (HSV1-tk positive) cells were treated with various concentration of carbocyclic ddIVDU, and GCV. Cytotoxicity was measured by the MTS methods. For in vitro uptake study, MCA and MCA-tk cells were incubated with 1uCi of [(125)I]carbocyclic ddIVDU. Accumulated radioactivity was measured after various incubation times. RESULTS: The synthesis of ddIVDU and precursor for radioiodination were achieved from cyclopentadiene in good overall yield, respectively. The radioiododemetallation for radiolabeling gave more than 80% yield with > 95% radiochemical purity. GCV was more toxic than carbocyclic ddIVDU in MCA-tk cells. Accumulation of [(125)I]carbocyclic ddIVDU was higher in MCA-tk cells than MCA cells. CONCLUSION: Biological data reveal that ddIVDU is stable in vitro, less toxic than ganciclovir (GCV), and selective in HSV1-tk expressed cells. Thus, this new carbocyclic nucleoside, referred to in this paper as carbocyclic 2',3'-didehydro-2',3'-dideoxy-5- iodovinyluridine (carbocyclic ddIVDU), is a potential imaging probe for HSV1-tk.

Desarrollo tecnológico y estudio de estabilidad del colirio de idoxiuridina 0, 1 por ciento / Technological development and study of 0.1 Idoxuridine (eyedrops)

La idoxiuridina, que se asemeja a la timidina, inhibe la timidílico fosforilasa y las polimerasas específicas del ADN que son necesarias para la incorporación de la timidina en el ADN del virus. La idoxiuridina se incorpora en el ADN defectuoso que incapacita al virus, para infectar o destruir tejidos o para reproducirse. El objetivo del presente trabajo consistió en el desarrollo tecnológico de una formulación de idoxiuridina, para su administración por vía ocular, que cumple con todos los requisitos de calidad exigidos para el producto, como: características organolépticas, pH, valoración y esterilidad, con un tiempo de vida útil de 2 años, a temperatura de 2 a 8 oC, y que mantuvo invariables sus características físicas, químicas y microbiológicas durante el estudio de estabilidad realizado mediante el estudio de estabilidad acelerado a 25 oC y vida de estante de 2 a 8 oC, por espacio de 6 meses y de 24 meses, respectivamente.

Nuclear Imaging of Cellular Proliferation / 대한핵의학회잡지

Tumor cell proliferation is considered to be a useful prognostic indicator of tumor aggressiveness and tumor response to therapy, but in vitro measurement of individual proliferation is complex and tedious work. PET imaging provides a noninvasive approach to measure tumor growth rate in situ. Early approaches have used 18F-FDG or methionine to monitor proliferation status. These 2 tracers detect changes in glucose and amino acid metabolism, respectively, and therefore provide only an indirect measure of proliferation status. More recent studies have focused on DNA synthesis itself as a marker of cell proliferation. Cell lines and tissues with a high proliferation rate require high rates of DNA synthesis. [11C]Thymidine was the first radiotracer for noninvasive imaging of tumor proliferation. The short half-life of 11C and rapid metabolism of [11C]thymidine in vivo make the radiotracer less suitable for routine use. Halogenated thymidine analogs such as 5-iodo-2-deoxyuridine (IUdR) can be successfully used as cell proliferation markers for in vitro studies because these compounds are rapidly incorporated into newly synthesized DNA. IUdR has been evaluated as a potential in vivo tracer in nuclear medicine, but the image quality and the calculation of proliferation rates are impaired by its rapid in vivo degradation. Hence, the thymidine analog 3'-deoxy-3'-18F-fluorothymidine (FLT) was recently introduced as a stable proliferation marker with a suitable nuclide half-life and stable in vivo. [18F]FLT is phosphorylated to 3-fluorothymidine monophosphate by thymidine kinase 1 and reflects thymidine kinase 1 activity in proliferating cell. [18F]FLT PET is feasible in clincal use and well correlates with cellular proliferation. Choline is a precursor for the biosynthesis of phospholipids (in particular, phosphatidylcholine), which is the essential component of all eukaryotic cell membranes and [11C]choline, which is a new marker for cellular proliferation.

Comparsion between intracerebral biodistribution of [125I] IUdR in a rat glioma model and [125I] IUdR uptake in spheroid multicellular culture: effect of proliferative heterogencity

Radioiodinated iodo deoxyuridine [lUdR] is a novel, cycle-specific agent that has potential for the treatment of residual malignant glioma after surgery. Because this thymidine analogue kills only roliferating cells. However, maligment cells which are not synthesizing DNA during exposure to the radio pharmaceutical will be spared. To determine whether tumour incorporation [125 I]IUdR could be enhanced by protracted administration we employed three different delivery methods such as single injection, polymer implant and using osmotic pump in an in vivo study in compare with an in vitro study using multicellular glioma spheroids of a range of sizes and incubation times. We used a C6 cell line, growing in the brains of Wistar rats, as a glioma model and compared biodistribution of radiopharmaceutical in glioma cells by using autoradiography method. Au toradiogarphy technique also used to describe means of [125 I] lUdR incorporation at different times and depths within UVW multicellular glioma spheroids of a range of sizes. Twenty-four hours after administration of drug, autoradiography of brain section demonstrated nuclear uptake of the radiopharmaceutical in cells throughout tumour while normal brain cells remained free of radioactivity. The [125 I] IUdR labeling indices [percent +/- s.e.m.] achieved were 6.2 [0.4] by single injection, 22.5 [4.1] using a sustained release polymer implant [poly lactide-co-glycolide] and 34.3 [2.0] mini-osmotic pump. The results of the spheroids study confirm that incorporation of [125 I] lUdR decreased markedly with increasing size of spheroid. The distribution of lUdR was uniform thought small spheroids [<200 /micro], while the concentration of lUdR occurred predominantly in the peripheral cells of larger spheroids. The lUdR uptake enhancement occurred by increasing the incubation time from 52 hours to 104 hours i.e. one or two multiples of the initial volume doubling time. The results obtained from in vitro and in vivo studies emphasize the need for a sustained delivery system as a prerequisite for effective treatment. These findings are also encouraging for the development of a sustained release for radiolabel led IUdR for use in the treatment of intracranial tumours, particularly in the immediate postoperative setting

Idoxuridina jalea: parte II: estabilidad / Idoxuridine gel: part II: stability

Se realizó el estudio de estabilidad de una jalea de idoxuridina para el tratamiento de la gingivo estomatitis herpética aguda, mediante una técnica de análisis específica por cromatrografía líquida de alta resolución, con la que se puede cuantificar el contenido de idoxuridina en presencia de sus productos de degradación. Las muestras se almacenaron a diferentes temperaturas y se analizaron de acuerdo con el diseño previamente establecido. se demostró que la formación es estable químicamente y que la reacción de degradación hidrolitíca de la idoxuridina en la jalea es de primer orden; se plantea para este producto una fecha de vencimiento de 5 años, si se almacena a temperatura de refrigeración

Modulation of thymidine kinase activity: a biochemical strategy to enhance the activation of antineoplastic drugs

Thymidine kinase is a key enzyme responsible for the activation of several anticancer and antiviral drugs. As the first enzyme in the salvage pathway of thymidine, it is regulated by the feedback inhibition exerted by the end-product of the pathway, namely thymidine 5'-triphosphate. 5'-Aminothymidine is a non-toxic analogue of thymidine capable of interfering with this regulatory mechanism. In fact, it has been shown that 5'-aminothymidine increases the cytotoxicity and metabolism of various thymidine analogues currently in use of the clinic as antineoplastic agents. This mini-review article focuses in the evidence supporting the role of 5'-aminothymidine as a potential prototype drug for a new class of anticancer agents: drugs which affect the regulation of key metabolic pathways that determine the efficacy of agents with cytotoxic activity. The mechanism of action, antineoplastic activities and basis for selectivity in tissue culture models are also described

Idoxuridina jalea: determinación cuantitativa / Idoxuridine jelly: quantitative determination

Se desarrolloó un método para la valoración de idoxuridina en una jalea, mediante la cromatrografía líquida de alta resolución, en el que se utilizó fase reversa de C-8 como fase estacionaria, metanol-agua como fase móvil, sulfatiazol como stándar interno y detección ultravioleta a Landa=295 nm. Previamente se extraen los parabenos y se precipita la hodroxipropilmetilcelulosa que interfiere en la determinación de idoxuridina por dicho método. Los resultados obtenidos fueron reproducibles y el recobrado se encontró dentro de los límites establecidos

Gingivoestomatitis herpética primaria ¿Una urgencia médica o estomatológica? / Primary herpetic stomatitisÑ a medical or a dental emergency?

El estudio de la gingivoestomatitis herpética aguda (GEHA) ha constituido un tema de interés para nosotros en la práctica periodontal. La mayor parte de los autores plantea la aplicación de un tratamiento sistemático para dicha enfermedad y existe un criterio casi universal de que sus lesiones pueden mantenerse hasta 14 días. Decidimos emprender la búsqueda de literatura actualizada y encontramos algunos estudios muy serios que planteaban, entre otras, la aplicación de una quimioterapia específica con la utilización de una primidina análoga: la idoxuridina. A partir de ese momento comenzamos el estudio de la GEHA en 20 niños con diagnóstico clínico de la misma. El uso de este medicamento fue efectivo para nuestro pacientes y por tanto sugerimos su estudio y aplicación

Antivirais / Antivirals

Doenças causadas por vírus representam dificuldades terapêuticas. O conjunto de medicamentos antivirais disponíveis é ainda relativamente pequeno, mas tem crescido nos últimos anos em razäo de enormes investimentos materiais e de talentos: a síndrome da imunodeficiência adquirida é, certamente, o motivo principal dessa procura, mas näo o único. Com a presente atualizaçäo, dedicada a oftalmologistas, o modo de açäo, as aplicaçöes, os efeitos adversos, as apresentaçöes e a posologia dos principais quimioterápicos desse grupo, assim como novidades e perspectivas, säo aqui resumidas

Atualizaçäo terapêutica em herpes simplex vírus / Therapeutic actualization in herpes virus

É apresentada uma revisäo das publicaçöes mais recentes sobre o herpes simplex vírus, com ênfase às relaçöes com transmissäo, tratamento e controle

Comparison of the antiviral activity and toxicity of a protein magnesium ammonium phospholinoleate anhydride polymer with other antiviral drugs

1. SB-73, a magnesium ammonium phospholinoleate anhydride aggregate, exhibited antiviral action in vitro in the concentration range of 50 to 100 µg/ml against herpes simplex type 1, stomatitis vesicular virus, adenovirus type 5, and in vivo in the dose range of 0.7 to 1.3 mg/Kg against canine parvovirus distemper virus. 2. The lethal dose (LD50) was 2.71 ñ 1.55 g/Kg body weight in mice inoculated intraperitoneally. Oral ingestion of the aggregate up to 30 g/Kg body weight by mice had no lethal effects during the 14 days of observation. 3. In in vitro cytotoxicity experiments with fibroblasts (V-79 Chinese hamster cell line), no toxic effects were observed with SB-73 concentrations (120 µg/ml) having antiviral activity. 4. In a cellular proliferation experimental using hamster V-79 cells, we observed 72% proliferation after treatment of the cells with a high concentration (500 µg/ml) of SB-73. 5. Compound SB-73 showed no genotoxicity for human lymphocytes at concentrations of 100 µg/ml. 6. When the cytoxicity and genotoxicity of SB-73 wee compared with those of acyclovir, idoxuridine and AZT at 500µg/ml concentration the compound was found to have effects similar to those of acyclovir

Dispositivo intrauterino intramioma / Intramyoma intrauterine device

"Señuelos extraviados" de un DIU no significan necesariamente perforación uterina. Este artículo decribe un caso de un anillo de Zipper incrustado en un mioma. El diagnóstico fue hecho después de una histeroscopía complicada. Es razonable tener presente esta posibilidad cuando se investiga un caso de "señuelos extraviados". Tal como ha sido publicado, es muy difícil asegurar si el mioma creció alrededor del DIU o el mioma fue perforado al momento de la inserción. Las evidencias histológicas conducen hacia la primera opción

Acquired Punctal Stenosis Treated by Laser Punctoplasty

Occlusion or stenosis of lacrimal punctum may be from congenital origin, but can be caused by a variety of factors such as inflamations, tumors, traumas, and systemic diseases that invade punctum. Occlusion or stenosis of punctum was reported after use of drugs, such as strong miotics or idoxuridine also. The initial procedure to be employed in punctal stenosis caused by most factors is punctal dilation. In 1985, Awan used a new application of laser in the treatment of punctal stenosis, reporting good result. Two Korean adults with acquired punctal stenosis were treated by laser punctoplasty with good results.