[Association between oral conditions and colorectal cancer: A literature review and synthesis]. / Association entre les affections buccodentaires et le cancer colorectal: une revue et synthèse de la littérature.

BACKGROUND: Chronic periodontitis and tooth loss are chronic oral conditions that, in recent decades, have been implicated in the occurrence of certain types of cancer. In this review, we address the question of whether colorectal cancer is associated with these oral conditions. RESULTS: Epidemiological studies evaluating a potential association between periodontitis, tooth loss and colorectal cancer are scarce. However, several mechanisms argue in favor of this association, notably inflammation, nutrition and possibly infection by specific bacteria, as suggested by this literature review.

On-line monitoring of physiological parameters of insect cell cultures during the growth and infection process.

On-line monitoring of insect cell cultures used for the production of recombinant proteins with the baculovirus expression vector system (BEVS) provides valuable tools for the optimization, operation, and control of the production process. The relative permittivity (epsilon') and CO(2) evolution rates (CER) were measured on-line using the biomass monitor and the infrared CO(2) analyzer, respectively. The growth and infection phases of two different cell lines, Spodoptera frugiperda (Sf-9) and Trichoplusia ni(High-5), were monitored using the above measurements. These in turn were correlated to the progress of the culture by using the off-line measurements of protein produced, virus titer, and biovolume, which is the product of viable cell density and mean cell volume. The epsilon', CER, and the biovolume profiles were closely matched during the growth phase of cells when grown in a batch or fed batch culture. The relationship became more complex when the cultures were either in stationary phase or in the postinfection phase. The epsilon' profile was found to be a good indicator of the process of synchronous baculoviral infection, showing a plateau between 18 and 24 h postinfection (hpi), the period during which budded virus is produced, and a peak at approximately 48 hpi correlated to the onset of accelerated cell lysis. The CER profile continues to increase after the growth period with a peak around the 24 hpi period, after which there is a decline in the profile corresponding to release of virus as seen from virus titer determinations. This was examined for Sf-9 cultures under conditions of cell densities from 3 to 50 x 10(6) cells/mL and MOI values ranging from 0.001 to 1000. The profiles were found to be similar also in the case of the High-5 cells. Thus both measurements give reliable information regarding the physiological status of the cells as seen from their correlation to virus and protein production. A further combination of these with the off-line measured parameters such as the biovolume and metabolite concentrations can give a more detailed understanding of the process and help in the better design and automation of these processes.

Interactive cytotoxicities of selected organic and inorganic substances to brown cells of Mercenaria mercenaria.

Toxicities of binary mixtures of Cu2+, Cd2+, benzo(a)pyrene [B(a)P] and N-ethylmaleimide (NEM) were screened using the in vitro neutral red (NR) assay to test the hypothesis that combined toxicity is more than or less than additive relative to the influence of each mixture constituent on toxicant uptake and brown cell lysosomal membrane stability. Significant cytotoxicity was observed at 25 mumol/L Cu2+, 500 mumol/L Cd2+ and 25 mumol/L NEM. B(a)P at 12 mumol/L exerted no toxicity under the conditions of the assay. Interactions between Cu2+ and NEM, between Cd2+ and NEM, and between Cd2+ and B(a)P significantly influenced brown cell survival. Comparison of observed joint toxicity with estimates made using a model of independent joint action indicates that interactive effects are less than additive in character. The 3-way interaction involving Cu2+, B(a)P, and NEM also affected brown cell survival to a statistically significant degree. However, the interactive cytotoxicity of this mixture is attributable mainly to the combined effect of Cu2+ and NEM. Results also indicate that new hypothesis and additional experimentation are needed to understand the interactive toxicity of mixture constituents.

Influence of salinity and temperature on acute toxicity of cadmium to Mysidopsis bahia molenock.

Acute toxicity tests were conducted to compare estimates of toxicity, as modified by salinity and temperature, based on response surface techniques with those derived using conventional test methods, and to compare effect of a single episodic exposure to cadmium as a function of salinity with that of continuous exposure. Regression analysis indicated that mortality following continuous 96-hr exposure is related to linear and quadratic effects of salinity and cadmium at 20 degrees C, and to the linear and quadratic effects of cadmium only at 25 degrees C. LC50s decreased with increases in temperature and decreases in salinity. Based on the regression model developed, 96-hr LC50s ranged from 15.5 to 28.0 micrograms Cd/L at 10 and 30% salinities, respectively, at 25 degrees C; and from 47 to 85 micrograms Cd/L at these salinities at 20 degrees C. Trimmed Spearman-Karber method used in analysis of a second data set yielded estimates at 20 degrees C and 25 degrees C comparable to those of multiple regression analysis. At 30 degrees C, the 96-hr LC50 was less than 11 micrograms/L. The relationship of median tolerance to cadmium concentration and exposure time was related to the interaction of both factors and independent of salinity between 10 and 30% at 25 degrees C. The quadratic model predicts mortality of 50% following exposures of less than 12 hr to the highest concentration examined (92 micrograms/L). For exposure durations of 16 and 24 hr, 50% mortality is predicted to occur at 78 and 56 micrograms/Cd/L, respectively.

[Treatment of dentin hypersensitivity: a retrospective and comparative study of two therapeutic approaches]. / Le traitement de l'hypersensibilité dentinaire: une étude rétrospective et comparative de deux approches thérapeutiques.

Stimulation on exposed dentine at the enamo-dentinal junction is often painful and uncomfortable for the affected patient. Two hundred and forty-four subjects suffering from dentinal sensitivity, aged from 18 to 48 years old, were treated with two types of desensitizing agent. In this study, we used sodium fluoride (Duraflor) and calcium hydroxide (Dycal catalyst). The desensitizing agent is first applied on the exposed dentine and then burnished, without local anaesthesia, until all sensitivity has disappeared. After the first session, 100% of the subjects were desensitized. All subjects were seen 1, 2, 3, 6, 13 and 26 weeks after the first application. After 6 months, 94% of the subjects treated with calcium hydroxide (Dycal) and 87% of those treated with sodium fluoride (Duraflor) were still desensitized. This difference is statistically significant at alpha = 0.01 (Anova test). In conclusion, our study reveals that both calcium hydroxide (Dycal) and sodium fluoride (Duraflor) are effective in the treatment of dentinal hypersensitivity. A slight significant advantage in using calcium hydroxide is also noted.

Individual and combined cytotoxic effects of cadmium, copper, and nickel on brown cells of Mercenaria mercenaria.

An assay based on the lysosomal incorporation of neutral red dye by brown cells of Mercenaria mercenaria (Bivalvia) was used to measure the cytotoxicity of Cd2+, Cu2+, and Ni2+ singly and in combination. Cytotoxicity was a linear function of Cd2+ concentration 0.1-1.5 mM and Cu2+ concentration between 10 and 100 microM. Nickel was not cytotoxic at concentrations as high as 10 mM. The presence of Cu2+ lessened the cytotoxic effect of Cd2+. Ni2+ did not affect cytotoxicity in combination with either Cu2+ or Cd2+.Ni2+ inflated estimates of cell survival by the neutral red assay in this study. Cells exposed to Ni2+ yielded measured quantities of neutral red dye in excess of those measured in cells from control treatments.

[Disinfectants and sterilizants for dental instruments]. / Les désinfectants et stérilisants pour instruments dentaires.

A comparative study of ten (10) products recommended for disinfection and/or sterilization of dental instruments is detailed. Four (4) out of fourteen (14) characteristics have been evaluated, namely corrosive power, monthly cost, odor and availability.

Dissolved carbon dioxide accumulation in a large scale and high density production of TGFß receptor with baculovirus infected Sf-9 cells.

Production of a TGFß receptor with high density baculovirus infected Sf-9 cells (7×10(6)cells ml(-1)) served as a test run for a retrofitted 150 L microbial fermentor. The entire 110 L batch run was performed in serum free medium, with an addition of a concentrated amino acid and yeastolate mixture at the time of infection. This addition strategy has been proven effective at a small scale by enabling cultures to maintain maximum product yield. In the bioreactor however, while cellular growth was comparable to that of the smaller scale control, TGFß receptor production was three fold below the control. To minimize the mechanical stress, low flow rate of pure oxygen was used to control the dissolved oxygen at 40%. As a consequence, it seems that this aeration strategy involved an accumulation of dissolved carbon dioxide that in turn inhibited the protein production. A model has been developed that estimated the CO(2) partial pressure in the culture to be in the vicinity of 0.15 atm. The effect of dissolved CO(2) at this concentration has been assessed at smaller scale for TGFß receptor and ß-gal expression, in controlled atmosphere incubators.

On-line monitoring of the progress of infection in Sf-9 insect cell cultures using relative permittivity measurements.

The use of on-line relative permittivity (epsilon') measurements for monitoring cultures of Sf-9 cells was evaluated in a batch culture and a batch infected with a baculovirus expressing beta-galactosidase. It was found that viable cell density and volume essentially accounted for all the variation in epsilon' in both non-infected and synchronously infected cultures, indicating that the epsilon' of a cell suspension was sensitive only to changes in the viable cell population. Additionally the parameter provided clearly defined signposts of the progress of the infection.

[Choice of antibiotics in periodontology]. / L'antibiothérapie de choix en parodontie.

For periodontal treatment, the use and choice of antibiotics is a controversial matter. There are many medical reasons for prescribing antibiotics before, during and after periodontal treatment. The purpose of this paper is to review the indications and reasons for antibiotherapy in periodontics. Research is not very advanced in this domain and there is a need to understand the indications for antibiotherapy in periodontics.