Genotoxicity and cytotoxicity of mineral trioxide aggregate and regular and white Portland cements on Chinese hamster ovary (CHO) cells in vitro

Objective. Recently, mineral trioxide aggregate (MTA) and Portland cement have been used in dentistry as root-end-filling materials. However, the reported results concerning the biocompatibility of these materials are inconsistent. The goal of this study was to examine the genotoxicity and cytotoxicity of MTA and Portland cements in vitro by the single-cell gel (comet) assay and trypan blue exclusion test.Study design. Chinese hamster ovary (CHO) cells were exposed to MTA and regular and white Portland cements at final concentration ranging from 1 to 1000 mu g/mL for 1 h at 37 degrees C.Results. All compounds tested did not show genotoxic effects in all concentrations evaluated. No significant differences (P > .05) in cytotoxicity were observed for all compounds tested.Conclusions. Taken together, our results suggest that MTA and Portland cements are not genotoxins and are not able to induce cellular death.

Validity and reproducibility of a laser fluorescence system for detecting the activity of white-spot lesions on free smooth surfaces in vivo

The aim of the study was to determine the reproducibility and validity of DIAGNOdent in detecting active and arrested caries lesions on free smooth surfaces. Volunteers were selected from state schools of Piracicaba, São Paulo, Brazil. Overall, 220 lesions were clinically examined. Two specially trained ('calibrated') examiners performed both clinical and laser evaluations independently, and after a 1-week interval, the examinations were repeated, the intra-examiner agreement for the laser evaluation was substantial (kappa(ex1) = 0.79, kappa(ex2) = 0.71). There was almost perfect agreement between the two examiners for the clinical examination (kappa(ex1) = 0.95, kappa(ex2) = 0.85). The inter-examiner agreement showed substantial reproducibility (kappa = 0.77) for the laser examination and almost perfect agreement (kappa = 0.85) for the clinical evaluation. The validation criterion was the clinical examination of white spots, recorded as active or arrested. The sensitivity was 0.72 and the specificity was 0.73, which indicates that the DIAGNOdent was a good auxiliary method for detecting incipient caries lesions on free smooth surfaces. The utilization of both methods can improve the efficacy of caries diagnosis. Copyright (C) 2002 S. Karger AG, Basel.

The dawn lek of the Swallow-tailed Hummingbird

We studied the lek behavior of the Swallow-tailed Hummingbird (Eupetomena macroura) in an urbanized area in S (a) over tildeo Paulo state, Southeastern Brazil. During the 22-month study we identified a total of 26 lekking territories in one lek that covered an area of approximately 12 ha. The lek was active throughout the year; the number of singing males per morning ranged from 6-15. The abandonment of territories and the establishment of new ones caused continuous rearrangement of lek boundaries. Lekking territories had a mean size of 217 m(2) and were separated from each other by 24-120 m. on average, males started singing 27 min before sunrise and kept singing for 17 min. At the end of this period and after a few minutes of silent perching, they abandoned their lekking territories until the next morning. During the singing period. males spent 72-100% of the time inside their territories. The lek behavior of E. macroura is unusual compared to other lekking hummingbirds because of the short daily period of lekking, restricted to just before Sunrise. Since males and females of E. macroura possibly defend feeding territories throughout the rest of the day, the short lekking period may represent a tradeoff between two different time budget pressures from lekking and feeding activities.

Hematology of free-living marsh deer (Blastocerus dichotomus) from Southeast Brazil

This work reports basic hematologic values of a sample of a population of free-living marsh deer (Blastocerus dichotomus) living by the Parana River in Southeast Brazil. Hematologic values are presented separately for male, female, and young animals as well as for anesthetized and nonanesthetized cervids. Nonanesthetized deer restrained by physical means had significantly higher erythrocyte indices and total leukocyte counts. Comparisons of blood parameters of anesthetized animals of different ages and gender differed slightly, with only two significant differences observed: young animals had significantly higher red blood cell counts than adult males and a lower blood total protein content when compared to adult females. Results indicate that two main reference ranges for blood values should be considered for marsh deer, for blood obtained from anesthetized or physically restrained individuals.