Identification and characterization of a rat protein (p 105) auto-antigenic in rats bearing a progressive syngeneic colon carcinoma.

Sera from BDIX rats inoculated with 2 tumor clones derived from a single syngeneic colon carcinoma were assayed by Western blotting for the presence of antibodies against the grafted tumor. The PROb clone is progressive and produces metastases. We observed that rats bearing this tumor developed antibodies against an unglycosylated water-soluble protein of 105 kDa. The magnitude of this humoral response, as assessed by the intensity of the signal on immunoblots, was inversely correlated with survival of the rats. Furthermore, rats inoculated with the REGb clone, which is immunologically rejected, never developed detectable antibodies against the tumor. Antisera from rats injected with PROb tumor detected p105 antigen in cellular extracts from the REGb clone and from a series of rat and human cell lines. This protein was also detected in variable amounts in some normal adult and fetal tissues. Treatment of PROb or REGb cells by either interferon-gamma or heat shock did not significantly alter the expression of the p105 auto-antigen.     

Mechanism of strength increase for a hydrothermal porcelain.

OBJECTIVES: The objectives of this study were to verify the formation of a hydrolyzed surface layer on Duceram LFC, to determine the effects of such a layer on mechanical material properties, and to identify a specific mechanism responsible for any strength increase observed. METHODS: Specimens were fabricated from dentin porcelain by a vibration blotting technique and were prepared to have either blunt or sharp surface flaws. Half of the specimens underwent accelerated aging. Specimens were fractured in three-point flexure to measure their strength, and fractographic analysis was used to determine fracture toughness and residual surface stress. Surface hardness and elastic modulus were measured using a microindentation method. Porcelain surface topography was examined using atomic force microscopy, and Fourier transform infrared spectroscopy was used to determine the composition of the surface layer. RESULTS: The aging treatment modified the porcelain surface topography but did not create a layer with increased hydroxyl ion content. Porcelain strength increased upon aging, and the increase was proportional to initial flaw severity. The apparent fracture toughness of sharp flaw specimens increased to match that for specimens containing blunt flaws upon aging. Surface hardness and elastic modulus decreased upon aging. SIGNIFICANCE: Previous studies on the strength increase of hydrothermal porcelain were contradictory because a variety of specimen preparation procedures were used. This study resolves the apparent contradiction by determining the effect of specimen preparation on material strength.     

Antiproliferative activity of taxol on human tumor and normal breast cells vs. effects on cardiac cells

The antiproliferative activity of the chemotherapeutic agent taxol was evaluated on 2 normal and 2 carcinoma human breast-cell lines and compared with its effects on newborn rat cardiac cells growing in vitro. Relatively little difference in ID₅₀ response (ranging from 0.6 to 2.0 ng/ml) to taxol was found between normal and tumorous breast epithelial cells. Arrhythmias and slowing of beat frequencies of cardiac cells were induced by taxol but at doses approximately 10 times higher than those necessary to inhibit proliferation in dividing cells. Microtubules assayed by immunostaining appeared to be similarly retracted around the nucleus in both breast and heart cells. Overall, our results suggest that taxol does not selectively inhibit the growth of tumor vs. normal human breast cells. They also support the hypothesis that effects on microtubule integrity are associated with effects on cardiac function and that the clinical cardiac activity of taxol already reported may be due, at least in part, to a direct effect of taxol on cardiac cells as demonstrated in these in vitro studies. Thus, caution is needed, in view of possible cardiac effects, when using taxol in future clinical protocols, especially when combined with other cardioactive agents such as Adriamycin.     

Exertional heatstroke and muscle metabolism: an in vivo 31P-MRS study.

An impairment of muscle energy metabolism has been suggested as a predisposing factor for, as well as a consequence of exertional heatstroke (EHS). Thirteen young men were investigated 6 months after a well-documented EHS using 31Phosphorus Magnetic Resonance Spectroscopy (31P-MRS). The relative concentrations of ATP, phosphocreatine (PCr), inorganic phosphate (Pi), phosphomonoesters (PME), and the intracellular pH (pHi) were determined at rest, during a graded standardized exercise protocol (360 active plantar flexions) and during recovery. Also the leg tissue blood flow was determined by venous occlusion plethysmography during the MRS procedure. Sixteen age-matched healthy male volunteers served as control group. In resting muscle, there were no significant differences between the groups as regards pHi, Pi/PCr, and ATP/PCr+Pi+PME ratios. During steady state exercise conditions, effective power outputs were similar for both groups at each level of exercise: 20, 35, and 50% of maximal voluntary contraction (MVC) of the calf muscle. No significant differences were shown between the two groups in Pi/PCr, pHi, or changes of leg blood flow at each level of exercise. At 50% MVC, Pi/PCr was 0.48 +/- 0.08 vs 0.47 +/- 0.05 (P = 0.96), pHi was 6.94 +/- 0.03 vs 6.99 +/- 0.02, respectively (P = 0.13). Finally, the rate of PCr resynthesis during recovery was not significantly different between the two groups: t1/2 PCr = 0.58 +/- 0.07 vs 0.50 +/- 0.05 min, respectively (P = 0.35). Therefore, no evidence of an impairment of muscle energy metabolism was shown in the EHS group during a standardized submaximal exercise using 31P-MRS performed 6 months after an EHS.     

Nosocomial viral infections in a pediatric service: example of rotaviral gastroenteritis and respiratory syncytial viral bronchiolitis]

Nosocomial infections are a preoccupation in a pediatric hospital mainly during the winter with bronchiolitis and gastroenteritis epidemics. We have examined the risk factors of nosocomial infections. MATERIAL AND METHODS: A prospective study was conducted between November, 1999 and March, 2000 in the infants units of the Le Havre hospital. We systematically listed the admissions and contacted the family after their discharge by phone. A geographic information system was implemented to display the epidemiological data; this software is able to illustrate the sectors at risk. RESULTS: During the study, 687 infants were hospitalized of whom 458 for bronchiolitis and community-acquired gastroenteritis. Mean age was 5.4 months old. No nosocomial bronchiolitis occurred. Prevalence of nosocomial gastroenteritis was 10% (68 cases including nine after discharge). Infants with nosocomial infection were younger than those with community-acquired infection (6.6 months vs. 11.2 months, P < 0.01). The mean length of stay was longer in nosocomial infection (7.7 vs. 4.1 days, P < 0.05). Among the infants with bronchiolitis, 16% have developed nosocomial intestinal infections (RR = 2.65, IC: 1.59-4.4; P < 0.01). The geographic analysis pointed the area with nosocomial risk (bedroom without water, nearness of nurse office and games room). CONCLUSION: Geographic information system is a part of the quality control system and may have some interaction effect on final decision making. Incidence of nosocomial infections showed the need for a prevention strategy in a pediatric hospital.     

Medical treatments of hyperactive child]

Treatment of hyperactive child is multimodal, a combination of behaviour therapy and medication. Stimulant drugs are the most often prescribed medications. In France, we use methylphenidate (Ritaline); its efficacy was demonstrated with mild side effects. New formulations of methylphenidate with prolonged action, and non-psychostimulant treatment (atomoxetine) are available in some countries, but not yet in France.