Capillary electrophoresis of DNA damage after irradiation: apoptosis and necrosis.

Apoptosis is a type of cellular death but also directly regulates tumorigenesis through different gene expression. This phenomenon is often used as end-point in studies of radio- and chemosensitivity of cancer cells. Restriction DNA fragments have been separated quickly, efficiently and successfully by capillary gel electrophoresis (CGE). In this study CGE has been applied to distinguish between the discrete pattern of degraded DNA produced by apoptosis and randomized DNA breaks produced by ionizing radiation. The influence of different variables has been discussed and an example of fast separation by CGE of the apoptotic fragments produced by UV light treatment is shown.

Antinociceptive effect of taurine and its inhibition by naxolone.

1. We have tested the effect of taurine on nociceptive stimulation provoked by chemical agent (acetic acid) and by the hot-plate test. 2. In the acetic acid test, taurine exerts an antinociceptive effect at every dose and time assayed. The observed effect was dose-related. 3. Naxolone pretreatment antagonizes the antinociceptive effect of taurine in the acetic acid test. 4. The results obtained in hot-plate test show that taurine did not significantly affect latency time for paw licking.

Role of GABAA and GABAB receptors and peripheral cholinergic mechanisms in the antinociceptive action of taurine.

1. Gabaergic and cholinergic mediation in the antinociceptive effect of taurine has been investigated in mice (acetic acid test) and rats (tail-flick test). 2. Scopolamine sulfate and methylnitrate exhibit intrinsic antinociceptive activity and increase the effect of taurine in mice. 3. Baclofen also increases the antinociceptive effect of taurine in mice. 4. Anticholinergic agents and bicuculline but not CGP 35348 antagonize the effect of taurine in rats. 5. These results suggest that the antinociceptive effect of taurine may be partly mediated by spinal GABAA receptors and peripheral cholinergic mechanisms.

[A reliability analysis of FACES III (the version in Spanish). Family Adaptability and Cohesion Evaluation Scales]. / Análisis de la confiabilidad de FACES III (versión en español).

OBJECTIVE: To determine through five methods (Cronbach's alpha, split, Guttman method, parallel and strict parallel) the confidence coefficient of FACES III, instrument validated on spanish version, and to evaluate it's consistency with these five statistical methods. DESIGN: Descriptive, cross-sectional. SETTING: Tlalpan Area, south of Federal District, México, divided into geo-statistical zones. PATIENTS AND OTHER PARTICIPANTS: A randomised sample of 270 dwellings with proportional coverage, based on 17,895 ordinary dwellings of the area. INTERVENTION: Domicile survey using FACES III (Family Adaptability and Cohesion Evaluation Scales); April-May 1995. MEASUREMENTS AND MAIN RESULTS: The confidence coefficient of FACES III spanish version was calculated using no standardised Cronbach's Alpha = 0.69; split I = 0.73 and split II = 0.66; Guttman method = 0.75; parallel = 0.69 and strict parallel = 0.53. CONCLUSIONS: Cronbach's coefficient demonstrated more advantages than the other statistical methods in relation with the ordinal measurement scale of FACES III. We suggest to take into consideration three important aspects for the correct confidence analysis of this kind of instruments: Variance analysis depending on the scale of items (F test, Friedman or Cochran) Inter-items interactions analysis (nonadditivity) and the use of the balance value as purge element of error' source. Analysis of Tukey estimate, coefficient of concordance (W) and Hotelling's T squared. It's necessary the evaluation and analysis of this aspects before the report of confidence's coefficient values whose can have hidden skew.

DNA damage and prediction of radiation response in lymphocytes and epidermal skin human cells.

The success of radiotherapy in eradicating tumours depends on the total radiation dose, but what limits this dose is the tolerance of the normal tissues within the treatment volume. Studies involving fibroblast survival have demonstrated the theoretical feasibility of a predictive assay of radiation sensitivity, but such an assay is still far from clinical application. Using pulsed-field gel electrophoresis (PFGE), we have quantified the initial "apparent" number of DNA double-strand breaks (dsb) induced by the radiation as an alternative measure of sensitivity in 2 different normal cell types from the same patients, epidermal skin cells and lymphocytes. We found significant inter-individual variation in the measured dsb (1-5 dsb/Gy/DNA unit). We also found a linear correlation between molecular damage in lymphocytes and skin samples from the same patient (slope = 0.83; r = 0.694; p = 0.0001). These results suggest that the initial number of dsb could be used as an indicator of the in vivo response to radiation.