Evaluation of genotoxic potential of peptides used in nuclear medicine (PSMA -617 and -11, and ubiquicidine 29-41) using a flow-cytometric, semi-automated analysis of micronuclei frequency in cell cultures.

Assays that rely on the assessment of frequency of micronuclei are important standard techniques currently used to quantify potential genotoxic damage after exposure to chemical or physical agents, such as ionizing radiation, or in pre-clinical studies, to assessment of the genotoxic potential of drugs or its components. The experiments are usually performed using conventional microscopy, but currently the protocols are being upgraded to automated approaches based on flow cytometry protocols based on the elimination of the plasma membrane by chemical agents, allowing quantification by flow cytometry. In this work, the genotoxic potential of peptides used as components of radiopharmaceuticals (PSMA-617 and 11 and Ubiquicidine) was evaluated exposing CHO-KI cells to a wide range of concentration (0.1X and 100X the maximum allowed concentration to human adults). Incubation with PSMA-11 or UBI29-41 did not induce genotoxicity. After 24 h of incubation, PSMA-617 induced genotoxicity only in non-practical concentration (100-fold). Results corroborate the safety of the pre-drugs and the wide detection range of technique.

Efficient Non-Invasive Plasmid-DNA Administration into Tibialis Cranialis Muscle of "Little" Mice.

BACKGROUND: An alternative treatment for growth hormone deficiency based on hGH-DNA administration, followed by electro gene transfer, was investigated by injecting the plasmid into surgically exposed or non-exposed quadriceps or tibialis muscle of immunodeficient "little" mice. METHODS: An optimization of electrotransfer conditions via a new combination of high/low voltage pulses is presented. After 3 days, serum hGH was determined and in a 28-day assay, the relative growth parameters were compared. RESULTS: Both groups exhibited similar results: 5.0 ± 2.2 (SD) and 3.5 ± 0.9 ng hGH/ml (P>0.05; n=7) for the exposed quadriceps and non-exposed tibialis treatments, respectively. The final body weight increases were 16.1% for the quadriceps and 18.9% for the tibialis group. The tail and nose-to-tail length increases were 4.5% and 7.1% for the quadriceps and 4.8 and 4.6% for the tibialis group. The right and left femur length increases, obtained from radiographic measurements, were 16.9% and 12.7% for the quadriceps and 19.4% and 12.3% for the tibialis, respectively. A non-significant difference between exposed quadriceps and non-exposed tibialis treatments (P=0.48) was confirmed via a completely integrated statistical analysis. Circulating mIGF-1 levels were 126 ± 47, 106 ± 93 (P>0.05) and 38 ± 15 ng/ml for the quadriceps, tibialis and saline treatments, respectively. CONCLUSION: These results show that hGH-DNA administration into non-exposed tibialis muscle followed by the new HV/LV electrotransfer protocol was an equally efficient, less traumatic treatment, much more suitable for pre-clinical testing than administration into exposed quadriceps.

In vitro tests of resveratrol radiomodifying effect on rhabdomyosarcoma cells by comet assay.

Cancer is a global public health problem. Resveratrol is a defensive polyphenol that is synthesized by a wide variety of plants in response to exposure to ultraviolet radiation or also due to mechanical stress caused by the action of pathogens and chemical and physical agents. Grape vines have a high capacity to produce resveratrol, so grape juice and wine, mainly red wine, are considered good sources of resveratrol. The protective effects of resveratrol include promotion of antiinflammatory response, antitumor activity and prevention of degenerative diseases, reduced incidence of cardiovascular diseases and inhibition of platelet aggregation, among others. Therefore, resveratrol is considered to be a cell protector. However, at high concentrations, resveratrol promotes contrary effects by sensitizing cells. The aim of this study was to investigate in vitro the radiomodifying effect of resveratrol in culture of human rhabdomyosarcoma cells (RD) by applying the comet assay to evaluate the cell damage and repair capacity. The LD50 (lethal dose) obtained was 499.95 ± 9.83 Gy (Mean ± SD) and the CI50 (cytotoxicity index) was 150 µM in the RD cells. Based on these data, it was defined the gamma radiation doses (50 and 100 Gy) and resveratrol concentrations (15, 30 and 60 µM) to be used in this study. The results indicated that resveratrol acts as a cell protector at a concentration of 15 µM and has a cytotoxic effect at 60 µM. However, with the interaction of the gamma radiation, the concentration of 60 µM did not produce a statistically significant radiosensitizing effect.

Detection of Toxoplasma gondii by PCR and mouse bioassay in commercial cuts of pork from experimentally infected pigs

The distribution of T. gondii in commercial cuts of pork (ham, tenderloin, spareribs and arm picnic) by PCR and bioassay from experimentally infected pigs, was evaluated. Eighteen mixed breed pigs were divided into two groups (G). The G1 animals (n=10) were infected with 4 x10(4) oocysts of the T. gondii VEG strain and the G2 animals (n=8) were used as control. Pigs of both groups were slaughtered at 59th day after infection, and meat samples were collected for bioassay and PCR. All animals from G1 were positive by at least one or both tests, and all control animals were negative. T. gondii was identified in pork by mouse bioassay and PCR in 27/40 (67.5 percent) and in 9/40 (22.5 percent) of the evaluated samples, respectively. There were no statistical differences in the distribution of tissue cysts from commercial cuts of pork by bioassay (P>0.05). However, statistical differences were observed when mouse bioassay and PCR were compared (P<0.01).

Avaliou-se a presença de T. gondii em cortes comerciais de carne suína (pernil, lombo, costela e paleta), por meio do bioensaio e PCR, em animais experimentalmente inoculados. Dois grupos (G) foram formados. Os animais do G1 (n=10) foram inoculados com 4 x10(4) oocistos da cepa VEG e os do G2 (n=8) permaneceram como grupo-controle, não inoculado. Todos os animais foram abatidos no dia 59 após a infecção, quando foram colhidas as amostras de carne para a realização das provas de bioensaio e da PCR. Todos os suínos do G1 apresentaram-se positivos a pelo menos um dos testes de diagnóstico ou a ambos, e os do grupo-controle permaneceram negativos. Não houve diferenças significativas em relação aos tipos de cortes comerciais e à presença do parasita no bioensaio (P>0,05). O bioensaio foi capaz de detectar T. gondii em 27/40 (67,5 por cento) amostras e a PCR em 9/40 (22,5 por cento). O estudo mostrou diferença entre o bioensaio e a PCR (P<0,01).