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Rómulo L Cabrini

Publications and source records attributed to Rómulo L Cabrini.

8 recordsLinked to original sources
PubMed2005

Effect of titanium dioxide on the oxidative metabolism of alveolar macrophages: an experimental study in rats.

Metallic implants of titanium are used therapeutically in biomedicine because of its excellent biocompatibility. However, no metal or alloy is completely inert. We have previously shown that titanium oxide (TiO(2)) is transported in blood by phagocytic monocytes and deposited in organs such as liver, spleen, and lung 6 months after intraperitoneal injection (ip). Furthermore, it is well known that exposure to metal traces alters the cellular redox status. Thus, the aim of the present study was to determine the presence of titanium in target organs after chronic exposure, assess the potential structural alterations, and evaluate the oxidative metabolism of alveolar macrophages (AM) in the lung. Rats were ip injected with 1.60 g/100 g body wt of TiO(2) in saline solution. Organs (liver, spleen, lung) were processed for histological evaluation. Reactive oxygen species (ROS) in AM obtained by bronchoalveolar lavage (BAL) were evaluated using the nitroblue tetrazolium test and quantitative evaluation by digital image analysis. The histological analysis of organs revealed the presence of titanium in the parenchyma of these organs with no associated tissue damage. Although in lung alveolar macrophages TiO(2) induced a significant rise in ROS generation, it failed to cause tissue alteration. This finding may be attributed to an adaptive response.

Animals↗
PubMed2005

Kinetics of MTT-formazan exocytosis in phagocytic and non-phagocytic cells.

MTT is taken up by cells by endocytosis and reduced to formazan in the endosomal/lysosomal compartment. Formazan is deposited intracellularly as blue granules and is later exocytosed as needle-like formazan crystals. The present study involves an analysis of the pattern of exocytosis of MTT in different cell types showing clearcut differences in the response that can be associated to their ability to phagocytose. To further assess the characteristics of the exocytic mechanism of MTT/formazan, different experimental conditions were assayed. When culture medium with decreasing serum concentration was used as a metabolic modulator no variations were observed in the proportion of cells with formazan crystals. Conversely, the markedly sensitivity of phagocytic cells to increasing concentrations of genistein constituted a remarkable difference with non-phagocytic cells. These results must be considered when the modulation of MTT exocytosis is used as a signal of the progress of human diseases.

Animals↗
PubMed2005

Analysis of the epidemiological features of oral cancer in the city of Buenos Aires.

Oral cancer comprises 0.6 to 5% of all human malignant tumors. It is accepted in the literature that the clinical evolution of oral cancer has a bad prognosis, i.e. the five year survival rate ranges from 34% to 56%. The aim of the present study was to present a metaanalysis of the most relevant publications on oral cancer in the city of Buenos Aires, including our own series. The publications reviewed herein include the following series: 517 cases (1950-1970), 243 cases (1961-1968), 336 cases (1972-1984), and 274 cases (1992-2000). The clinical end-points evaluated were: age, distribution by sex, tumor site, presence of metastatic adenopathies, and clinical stage. A comparative statistical evaluation of the clinical parameters assessed was performed. Survival was evaluated by the test of Kaplan-Meier. The male/female ratio was 7.1:1 for the 1950-1970 period, 4.3:1 for the 1961-1968 period; 2.3:1 for the 1972-1984 period; and 1.24:1 in our series (1992-2000). The most frequent tumor site (21 to 35% of the cases) was the tongue. At the time of diagnosis, 60-71% of the patients had advanced TNM clinical stages (III and IV). Our follow-up revealed a five-year survival rate after diagnosis of 39%. The overall analysis of all the cases corresponding to the 1950-2000 period revealed that the prevalence of oral cancer in women has risen alarmingly and that the percentage of patients with advanced stages of tumor development continues to be high.

Adult↗
PubMed2004

Anatomic variations of the root canal of the rat according to age.

The mesial canal of the first lower molar of the rat has been used as an experimental model in Endodontics. The present study involves a detailed analysis of its structural variations as a function of age and thus contributes to its characterization and adequate use as an experimental model. We evaluated 60 molars of Wistar rats of different body weight: (group 1: 300-399 g, n=22; group 2: 400-499 g, n=16; group 3: 600-700 g, n=22). The samples were radiographed employing a standardized system. Total canal length and volume were measured on enlarged projections of the radiographs. Canal diameter was measured at coronary, middle and apical levels and employed to estimate the area of canal cross-section as an indicator of potential flow or metabolic interchange. From the second age group onwards, we detected radicular hypercementosis that increased canal length and resulted in the formation of a complex apical delta. The canal diameter decreased very significantly in the apical third. The estimated flow expressed in terms of the area of cross-section on the projection decreased from 1.2 mm2 in Group 1 to 0.05 mm2 in Group 2. Group 3 did not differ significantly from Group 2. The present results reveal that the spontaneous, age-related variations in canal anatomy described herein must be considered when performing experimental endodontics in rats.

Aging↗
PubMed2003

Titanium transport through the blood stream. An experimental study on rats.

Different metals are increasingly being used to manufacture implants, especially in the fields of dentistry and orthopedics. No metal or alloy is completely inert in vivo. The metal and the organic fluids interact releasing, for example, metallic products. Several hypotheses regarding the probable dissemination routes of titanium have been postulated, but its valence, the organic nature of its ligands and its potential toxicity have yet to be established. In a previous experimental study we demonstrated that i.p. injected titanium and zirconium oxides disseminate and deposit in organs such as liver and lung. The aim of this work was to study the eventual participation of blood cells in the transport mechanism of titanium employing the intraperitoneal injection of titanium oxide in rats as the experimental model. Twenty male Wistar rats, x: 100 g body weight, were intraperitoneally injected with 16x10(3) mg/kg b.w. of TiO(2) in saline solution. Blood samples were taken by heart puncture at 3 and 6 months; blood smears were performed and stained with safranin evidencing monocytes containing titanium particles. The results obtained in this study would indicate that one of the ways in which titanium is disseminated is through the blood stream, via blood cells.

Journal Article↗
PubMed2003

Cell-based quantitative evaluation of the MTT assay.

OBJECTIVE: To analyze the bioreduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) on a per cell basis and evaluate its modulation as a function of different stages of cell metabolism. STUDY DESIGN: Following MTT bioreduction, total optical density (TOD), cell area and specific activity (TOD/area) of V79 cells and cultured macrophages were recorded for individual cells by means of digital image analysis. The effect of different serum (0-10% vol/vol) or genistein (0-100 microM) concentrations was used to modulate the MTT-specific activity response. RESULTS: As cells in culture are heterogeneous in cell size, the contribution of each cell to the total amount of formazan formed per dish is variable. The production of formazan per cell as a result of MTT bioreduction was found to be proportional to cell size. CONCLUSION: Specific MTT-reducing activity was analyzed in phagocytes and nonphagocyte cells, revealing the utility of this variable in evaluating the MTT assay at the single-cell level.

Animals↗
PubMedDate not supplied

Exposure to subcutaneously implanted uranium dioxide impairs bone formation.

The introduction of uranium particles into subcutaneous tissue is a risk that affects workers engaged in the extraction, purification, and manufacture of uranium, as well as soldiers who are wounded with uranium shrapnel. The authors evaluated the effect of an internal source of an insoluble form of uranium on bone. Uranium dioxide powder (0.125 gm/kg body weight) was implanted subcutaneously in rats. After 30 days, animals exposed to uranium weighed less than controls. Bone formation activity in endochondral ossification and bone growth were also lower in the experimental animals, as evidenced by histomorphometric and morphometric methods. This is the first study to report bone damage resulting from continuous, nonlethal exposure to an insoluble compound of uranium dioxide over a period of 30 days.

Animals↗