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Cellular communication is required for the life of pluricellular organisms. The informations exchanged between cells belong to six major types of order to be executed, opposite each other: proliferate or differentiate; remain attached or migrate; survive or die. The cancer cell is genetically unstable, able to explore all the functions encoded by the genome and to consider every proliferative or migratory advantage for selecting it and transmit it to its descent. All the signalling pathways involved in proliferation or differentiation, in adhesion and migration, in survival and death may be altered by oncogenic alterations. These alterations are precisely those which can be targeted for therapy: from this observation was forged the concept of targeted therapy. We present here some examples of therapeutic targeting at the level of a major proliferation pathway by showing how it was possible to identify and characterise relevant targets, invent original new therapeutic tools and decipher the mechanisms of resistance which occur and hinder the success of targeted therapies. This example is the proliferation signalling pathway which starts from the activation of tyrosine kinase receptors by cognate growth factors and ends by the activation of transcription factors which trigger the transcription of the genes required for DNA replication, after undergoing through numerous intermediate molecules constituting the MAP kinase pathway: RAS, RAF, MEK and ERK., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Sequencing the human genome brings new tools for the individualisation of cancer chemotherapy, firstly thanks to the identification of polymorphisms of genes involved in anticancer drug metabolism or activity (Pharmacogenetics), and secondly thanks to the determination of tumour gene expression profiles and their relationship to chemosensitivity and chemoresistance (Pharmacogenomics). A few functional polymorphisms have been known for a long time (thiopurine methyltransferase, glutathion S-transferases), but several new ones have been identified recently, at the level of the genes encoding drug targets (thymidylate synthase), at the level of DNA repair enzymes (XPD) or at the level of transport proteins (MDR1). On the other hand, the research of correlations between gene expression profiles and chemosensitivity has been performed on the in vitro models of the National Cancer Institute and may allow crucial improvements in the identification of patients who would best take advantage of a specific chemotherapy. Clinical trials, first on a retrospective basis, then on a prospective one, are implemented to validate this approach.

Susceptibility to quinolones of aerobic gram-negative bacilli was assessed in a 2000-bed university hospital from 1992 to 2000. There was a significant downward trend in the rate of susceptibility to nalidixic acid (Nal) for Enterobacteriaceae as a whole from 1992 to 2000 (86% vs 82%), and E. coli (92% vs 84%), and an upward trend for K. pneumoniae (74% vs 82%), the latter being related to the control of the spread of epidemic ESBL producing strains. The overall susceptibility of Enterobacteriaceae to ciprofloxacin (Cip) paralleled the susceptibility to Nal: decreased susceptibility for Enterobacteriaceae as a whole (96% vs 89%) and E. coli (99% vs 91%). A clear decrease in the level of susceptibility to Cip occurred during the study period among the Nal-resistant strains as demonstrated by the decrease in the median zone diameter (D) observed among the Nal-resistant strains of E. coli (26 mm in 1992 vs 19 mm in 1998-2000). The zone diameter distribution pattern changed from an unimodal distribution in 1992 to a trimodal distribution in 2000 secondary to the occurrence of a population of resistant strains (D = 13 mm) and of a highly resistant population (D = 6 mm). Finally, the susceptibility to Cip of P. aeruginosa strains remained stable around 62% throughout the study period.

Although they differ only slightly from each other, the various anthracyclines have their own metabolic pathways and pharmacokinetic parameters. Doxorubicin and daunorubicin have a similar reduced metabolite which reaches low plasma levels in the case of doxorubicin, but is predominant in the case of daunorubicin: daunorubicinol. Aglycones are only formed in large quantities from aclarubicin: aklavinone. The plasma decay of doxorubicin levels is triphasic, with successive half-lives of 5 min, 1 h and 30 h. Unchanged daunorubicin is eliminated more rapidly from plasma, but its metabolite is eliminated more slowly. New anthracyclines such as pirarubicin are characterized by a large volume of distribution, suggesting a higher tissue fixation. These pharmacokinetic data must be kept in mind for the design of new protocols which are aimed to dose fractionation or tumor targetting.

Rapid ATB is a new automated system which performs antibiotic sensitivity testing of Enterobacteriaceae in four hours. It is composed of strips containing dehydrated antibiotics and a medium which ensures rapid bacterial growth, and of the equipment required for standardization of the inoculum, reading of results and interpretation. Strains are classified as susceptible or resistant according to the value of the growth index (IC) which is the ratio of growth in the presence of the antibiotic to growth of a control inoculum. Use of this system requires standardization. The main factors to control are state of the culture used to prepare the inoculum, standardization of the inoculum, incubation temperature (35 to 37 degrees C), and duration of incubation (4 to 5 hours). Variations of these factors usually induce significantly delayed growth. Under well standardized conditions, results are highly reproducible, as proved by testing ten strains ten times each by three investigators.

MICs and MBCs of five beta-lactams , i.e. ticarcillin, azlocillin, piperacillin, cefsulodin and ceftazidime for 20 strains of Pseudomonas aeruginosa were studied with inocula ranging from 10(3) to 10(9) CFU/ml. Each antibiotic exhibited an inoculum effect at 10(5)-10(7) CFU/ml. However, ticarcillin had smaller MIC and MBC increments than the four other drugs, making it more suitable in certain cases.

Rapid ATB Staph is a new, automated, four-hour procedure for testing the susceptibility to antibiotics of staphylococci. Results obtained with this method were compared to those recorded using agar dilution. For all tested antibiotics as a group (5 on 201 strains, 8 on 100 strains), overall agreement between the two sets of results was 96%. 1,809 susceptibility tests were performed, with only 24 minor discrepancies (1.3%) mainly involving cotrimoxazole, and 50 major discrepancies (2.7%) mainly involving doxycycline and chloramphenicol. Rapid ATB Staph clearly demonstrates the heterogeneous oxacillin-resistance of staphylococci as well as their inducible resistance to erythromycin. Our results show that this new system is a very accurate means for testing the susceptibility to antibiotics of staphylococci.

Five beta-lactams with anti-pseudomonal activity were tested against P. aeruginosa strains resistant to various concentrations of ticarcillin (from 256 to 8192 mg/l). MIC geometric means found for the totality of strains were as follows: 1.52 mg/l for ceftazidime; 1.80 mg/l for N-f-thienamycin; 4.79 mg/l for azthreonam; 17.3 mg/l for cefsulodin; 50.9 mg/l for cefoperazone. Activities of ceftazidime, N-f-thienamycin and azthreonam were not related to the level of ticarcillin resistance. Cefoperazone and, to a lesser degree, cefsulodin showed cross resistance with ticarcillin: these drugs were not active when ticarcillin MICs reached 512 mg/l and 4 096 mg/l respectively.

The bacteriostatic and bactericidal activities of five macrolides (roxithromycin, erythromycin, troleandomycin, josamycin and spiramycin) were tested against 284 bacterial strains belonging to various species of Gram positive (staphylococci, streptococci, pneumococci, Listeria sp, Corynebacterium sp, Bacillus sp) and Gram negative bacteria (Neisseria sp, H. influenzae, P. multocida). The activity of these compounds on the whole strains showed near results: 71.8% of susceptible strains to erythromycin and spiramycin, 70% to josamycin, 67.6% to roxithromycin, 65.5% to troleandomycin. Resisting strains were MLSB resistant cocci Gram positive, H. influenzae and P. multocida strains. Species usually less studied (nongroupable streptococci, Corynebacterium sp, Bacillus sp) were very susceptible to macrolides with MICS equal or inferior to 1 mg/l for the two last genus. A bactericidal effect was observed for 38.8% of 72 tested strains (erythromycin), 36.1% (josamycin), 34.7% (spiramycin), 31.9% (roxithromycin), 20.8% (troleandomycin). Among various tested species, this bactericidal effect concerned especially group A streptococci, N. meningitidis and Corynebacterium (except D2 and JK species).

The authors propose a method for the investigation of the muco-ciliary function of the nasal mucosa: they record the motion of radioactive particles, which are put by sonic nebulisation on nasal mucosa. The average speed is calculated by means of the analysis of sequential images and by the study of the variation of activity in relation to time in several main zones. A half-clearing time of the initial activity is also measured. The average speed is 8.33 mm/minute for normal persons and 2.36 mm/minute for a group of patients. This simple, accurate, non aggressive method is used for pharmacodynamic tests.

Sixty-nine ticarcillin-resistant strains (57 Gram negative bacilli and 12 S. aureus) were tested: MICs and MBCs were determined for clavulanic acid, ticarcillin, and both agents combined using a liquid micromethod. MICs were compared to results of disk antibiotic sensitivity tests. While clavulanic acid exhibits little antibacterial activity, its action is synergistic with that of ticarcillin making 100% of Staphylococci and 84.2% of Gram negative bacilli susceptible. Among the Gram negative bacilli tested, distribution is as follows: E. coli (9/9), Klebsiella (10/14), Enterobacter (1/3), Serratia (8/8), Proteus, Providencia (8/8), Salmonella (2/2), Acinetobacter (4/4), and Pseudomonas (6/9). Although strong bacteriostatic and bactericidal activities are already achieved with 4 mg, the best results are obtained with timentin 8 mg.

Bacteriostatic and bactericidal effects of three fluoroquinolones, norfloxacin, ofloxacin and pefloxacin, against 320 strains of Gram-negative bacilli were studied in vitro. For nalidixic acid-susceptible Enterobacteriaceae, susceptibility or resistance to second or third generation cephalosporins has no significant bearing on the MIC 90 of each of the three antibiotics. This is not so of nalidixic acid-resistant strains. All E. coli and K. pneumoniae strains are susceptible to the three quinolones (MIC 90 less than 3 mg/1); MICs 90 are higher for E. cloacae and S. marcescens; Serratia strains in particular have an MIC 90 greater than 6 mg/1. Nalidixic acid-susceptible Acinetobacter strains can be eliminated by ofloxacin or pefloxacin, whereas norfloxacin has the greatest activity against P. aeruginosa. We conclude that when multiresistant bacteria emerge, testing of susceptibility to the three quinolones studied may be useful.

Results given by Rapid-ATB, a new automated system for the four hour susceptibility testing of bacteria were compared in this study to results given by agar dilution test and disc agar diffusion test. For 100 Enterobacteriaceae strains tested against ten antibiotics, overall agreement between agar dilution test and Rapid-ATB was 99.4%. 6 major discordances concerning especially chloramphenicol were only detected in 1 000 realized susceptibility tests. Overall agreement between agar dilution test and disc agar diffusion test was 96.7%. Eighteen major discordances concerning alike chloramphenicol, but also doxycycline and nalidixic acid, and fifteen minor discordances were detected in this comparison. These results prove the high reliability of this new system which give results more precise than these of disc agar diffusion test.

Epidermal cells produce IL-1 and contra IL-1 which respectively stimulate and decrease fibroblast proliferation. In order to get better insight into the nature of keratinocyte-fibroblast interactions, we have analyzed the effect of soluble factors produced by unstimulated normal human keratinocytes and keratinocyte cell lines on the proliferation of normal human dermal fibroblasts. The results were compared to these obtained with human recombinant IL-1 and IL-2. We observed that: 1) normal keratinocytes (monolayers or stratified) released in the culture medium a factor stimulating fibroblast proliferation by 45 to 160%; 2) supernatants of unstimulated PAM 212 keratinocyte cell line also contained the stimulatory activity; 3) addition of IL-1 beta to the culture medium at concentration ranging from 0.1 to 1.000 U/ml induced a dose-dependent increase in fibroblast proliferation, whereas IL-2 was ineffective; 4) gel filtration analysis (ACA 54) of serum-free supernatant showed that the activity could be eluted from 3 peaks (Mw ranging from 10 to 20 kD). The present data show that unstimulated normal human keratinocytes produce soluble factor(s) (maybe related to IL-1) which stimulate human dermal fibroblast proliferation and which could be of major importance in the modulation of fibroblast metabolism, in vivo.

The antibacterial activity of fluoroquinolones (ciprofloxacin and ofloxacin) combined with beta lactams (ceftazidime and imipenem) or aminoglycosides (tobramycin and amikacin) against 22 P. aeruginosa isolated from the sputum of patients with cystic fibrosis was determined by the checkerboard method and compared with the combination of beta lactams (with ticarcillin) with aminoglycosides. Synergistic association (defined as FIC index less than ou = 0.5) was founded for 23 to 41% of strains with beta lactams (except imipenem)/aminoglycosides, in 18% with ceftazidime/ciprofloxacin, in 13% with imipenem/ciprofloxacin, in 0 or 13% with quinolones/aminoglycosides. For a FIC index less than ou = 0.75, the values are highest with 82% for ciprofloxacin/ceftazidime and 50% for ofloxacin/ceftazidime. The CMI's achieved in these combinations may allowed concentrations near to sputum concentrations.