Structural and Functional Characterization of Indane-Core CD4-Mimetic Compounds Substituted with Heterocyclic Amines

The human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer on the virion surface interacts with the host receptors, CD4 and CCR5/CXCR4, to mediate virus entry into the target cell. CD4-mimetic compounds (CD4mcs) bind the gp120 Env, block CD4 binding, and inactivate Env. Previous studies suggested that a C(5)-methylamino methyl moiety on a lead CD4mc, BNM-III-170, contributed to its antiviral potency. By replacing the C(5) chain with differentially substituted pyrrolidine, piperidine, and piperazine ring systems, guided by structural and computational analyses, we found that the 5-position of BNM-III-170 is remarkably tolerant of a variety of ring sizes and substitutions, both in regard to antiviral activity and sensitization to humoral responses. Crystallographic analyses of representative analogues from the pyrrolidine series revealed the potential for 5-substituents to hydrogen bond with gp120 Env residue Thr 283. Further optimization of these interactions holds promise for the development of CD4mcs with greater potency.

Gd3+:DOTA-Modified 2-Hydroxypropyl-β-Cyclodextrin/4-Sulfobutyl Ether-β-Cyclodextrin-Based Polyrotaxanes as Long Circulating High Relaxivity MRI Contrast Agents

A family of five water-soluble Gd³⁺:1,4,7,10-tetraazacyclododecane-1,4,7-tetraacetic acid-modified polyrotaxane (PR) magnetic resonance contrast agents bearing mixtures of 2-hydroxypropyl-β-cyclodextrin and 4-sulfobutylether-β-cyclodextrin macrocycles threaded onto Pluronic cores were developed as long circulating magnetic resonance contrast agents. Short diethylene glycol diamine spacers were utilized for linking the macrocyclic chelator to the PR scaffold prior to Gd³⁺ chelation. The PR products were characterized by ¹H NMR, gel permeation chromatography/multiangle light scattering, dynamic light scattering, and analytical ultracentrifugation. Nuclear magnetic relaxation dispersion and molar relaxivity measurements at 23 °C revealed that all the PR contrast agents displayed high spin-spin T₁ relaxation and spin-lattice T₂ relaxation rates relative to a DOTAREM control. When injected at 0.05 mmol Gd/kg body weight in BALB/c mice, the PR contrast agents increased the T₁-weighted MR image intensities with longer circulation times in the blood pool than DOTAREM. Excretion of the agents occurred predominantly via the renal or biliary routes depending on the polyrotaxane structure, with the longest circulating L81 Pluronic-based agent showing the highest liver uptake. Proteomic analysis of PR bearing different β-cyclodextrin moieties indicated that lipoproteins were the predominant component associated with these materials after serum exposure, comprising as much as 40% of the total protein corona. We infer from these findings that Gd(III)-modified PR contrast agents are promising long-circulating candidates for blood pool analysis by MRI.

Épidémiologie et résistance aux antibiotiques de Streptococcus pneumoniae en Île de France en 2001

OBJECTIVE

The authors wanted to assess the level of Streptococcus pneumoniae antibiotic resistance in Ile de France.

METHOD

In 2001, 637 clinical strains of S. pneumoniae were prospectively collected from 32 microbiology laboratories.

RESULTS

Fifty one percent of strains were isolated from children under 15 years of age and 49% from adults. In children, 76% of strains came from otitis media, 20% from blood culture, in adults most strains (92%) came from blood culture. The overall prevalence of non-susceptible penicillin pneumococci was 61% higher in children (73%) than in adults (50%). Among the non-susceptible penicillin pneumococci 21.8% were resistant (CMI > 1 mg/l). Strains with decreased susceptibility to amoxicillin and cefotaxime were 38% and 17% respectively. Resistant strains to these two drugs (CMI > 2 mg/l) were rare 2.6% and 0.4% respectively. Among other antimicrobial agents, rate of resistance was 63% to erythromycin, 47% to cotrimoxazole, 40% to tetracycline, and 23% to chloramphenicol. The most frequent serogroups were serogroups 19 and 14, respectively 23% and 18%. Serotypes included in heptavalent vaccine covered 90% of children strains under 2 years of age.

CONCLUSIONS

The prevalence of resistance to penicillin was high in children particularly in otitis media pus (76%).

[Acute pyelonephritis: bacteriological data and general course of germ resistance]

Recent bacteriological data concerning pyelonephritis mainly focus on sensitivity to antibiotics and virulence factors. Epidemiologically, and regardless of age and sex of the patients, E. coli remains the most often isolated pathogen. Only 55% of E. coli strains (43% if isolated during a nosocomial infection) are sensitive to amoxicillin. Resistance to parenterally administered third generation cephalosporins remain exceptional. Fluoroquinolones remain very active, particularly in community-acquired infections (>95% sensitive strains). P. aeruginosa, S. aureus and enterococci are mainly isolated during nosocomial infections or in patients with a history of previous hospital admissions. Adhesion factors to urothelial cells are of uppermost importance in the pathogenesis of urinary infection. Adhesins G borne by fimbriae P are mainly concerned. Also, hemolysin is very often present in strains responsible for pyelonephritis. As to the search for these factors in the diagnosis of pyelonephritis, particularly in children, further studies are needed. The choice of antibiotherapy not only rests upon antibiogram data, but also upon pharmacological characteristics of the antibiotic.

Multicentre Study of the Molecular Epidemiology, Serotypes and Antimicrobial Susceptibility Patterns of Invasive Streptococcus pneumoniae Invasive Isolated from Children in the Ille de France Area

Between January 1997 and April 2002, 73 consecutive invasive strains of Streptococcus pneumoniae were isolated from children under 16 years of age in four hospitals in suburban Paris. Their genetic diversity was investigated by serotyping and analysis of pulsed-field gel electrophoresis restriction patterns. Antibiotic susceptibility patterns were analysed by disk susceptibility testing and determination of minimal inhibitory concentrations. The genetic basis of macrolide resistance was investigated by polymerase chain reaction. Studies of penicillin and vancomycin tolerance were performed for each strain. Despite the high prevalence (45.2%) of penicillin-nonsusceptible Streptococcus pneumoniae, resistance to amoxicillin (1.4%) was rare, and no strain was resistant to cefotaxime. Overall, 4.1% of pneumococcal strains were resistant to penicillin. Penicillin or vancomycin tolerance was not detected in any of the 73 strains studied. Of the erythromycin-resistant strains (48%), all but one carried the ermB gene. No strains showing a decreased susceptibility to ciprofloxacin (MIC, >4 mg/l) or overexpressing an efflux pump inhibited by reserpine were isolated. The serotypes found, in order of frequency, were as follows: 18C, 14, 6B, 19F, 19A, 9V, 23F, 1, 7F, 9A, 38. Strains of penicillin-nonsusceptible Streptococcus pneumoniae belonged predominantly to serotypes 14, 6B, 9V, 9A, 23F, 19F and 19A. The seven-valent conjugated vaccine covered 85.5% of the serogroups isolated in children under 2 years of age and 65.6% of the serogroups identified in children over 2 years of age. The genetic analysis showed a high identity for some serotypes, such as 14/9V, 6B and 23F. The use of the seven-valent conjugated vaccine is a critical measure to prevent invasive pneumococci infections in children in the Ille de France area.

New substituted 1-(2,3-dihydrobenzo[1, 4]dioxin-2-ylmethyl)piperidin-4-yl derivatives with alpha(2)-adrenoceptor antagonist activity

The emergence of a novel theory concerning the role of noradrenaline in the progression and the treatment of neurodegenerative diseases such as Parkinson's and Alzheimer's diseases has provided a new impetus toward the discovery of novel compounds acting at alpha(2)-adrenoceptors. A series of substituted 1-(2, 3-dihydrobenzo[1,4]dioxin-2-ylmethyl)piperidin-4-yl derivatives bearing an amide, urea, or imidazolidinone moiety was studied. Some members of this series of compounds proved to be potent alpha(2)-adrenoceptor antagonists with good selectivity versus alpha(1)-adrenergic and D(2)-dopamine receptors. Particular emphasis is given to compound 33g which displays potent alpha(2)-adrenoceptor binding affinity in vitro and central effects in vivo following oral administration.

In vitro activity of teicoplanin against gram-positive cocci

The glycopeptide susceptibility of 443 clinical isolates of gram-positive cocci collected from nine general hospitals in 1996 was determined according to the recommendations of the CA-SFM (the Antibiogram Committee of the French Society for Microbiology). In total, 234 isolates of Staphylococcus aureus, 84 isolates of coagulase-negative staphylococci (CNS), 98 enterococci and 27 streptococci were collected. The mecA gene confirming resistance to methicillin was found in 42.7% of S. aureus isolates and 51.2% of CNS isolates. No resistance to teicoplanin and vancomycin was found in S. aureus but four isolates of CNS had an MIC of teicoplanin > or = 8 mg/L. All isolates of Enterococcus faecalis tested were susceptible to both glycopeptides. This study confirms that teicoplanin has a very good in vitro activity against gram-positive cocci, isolated in France from nosocomial infections.

Effect on benefits of earnings at ages 65 or older, 1995

A major policy issue for the Social Security program is the treatment of earnings of persons who have attained retirement age. This article discusses the retirement test and recomputation of benefit provisions, and provides statistical data for 1995. In 1995, about 806,000 persons aged 65-70 had significant earnings resulting in the withholding of benefits by the retirement test. About 1,659,000 persons aged 65 or older realized an increase in their benefit amount because of their earnings.

[Influence of mechanisms of Pseudomonas aeruginosa resistance on the bactericidal activity of third generation cephalosporins]

Survey of resistance of beta-lactam's resistance of P. aeruginosa have to be conducted. 410 strains of P. aeruginosa ticarcilline resistant have been studied. 52% of these strains were cephalosporinase producing alone or in combination with penicillinase. beta-lactam's inhibitors are not fully efficient upon these strains. Upon cephalosporinase producing strains bactericidal activity of C3G is difficult to obtain. At low concentration selection of strains with upper MICs is observed. This phenomenon is not observed at high concentration of antibiotics. Cefepime show a good bactericidal activity against P. aeruginosa.

Pharmacokinetics and bactericidal activities of one 800-milligram dose versus two 400-milligram doses of intravenously administered pefloxacin in healthy volunteers

Pefloxacin pharmacokinetics and serum bactericidal activities (SBA) against Escherichia coli and Staphylococcus aureus were compared after intravenous infusion of either a single 800-mg dose or twice-daily 400-mg doses into 16 healthy volunteers. Plasma pefloxacin concentrations were measured for up to 60 h, and SBAs were determined 1, 12, and 24 h after the start of the infusion. The mean areas under the concentration-versus-time curve for plasma were not different (138 versus 136 h.mg/liter). The mean clearances, volumes of distribution, and half-lives were also comparable. The mean (+/- standard deviation) maximal concentration after the 800-mg infusion was 12.11 +/- 1.35 versus 6.51 +/- 0.73 mg/liter after the first 400-mg infusion and 7.42 +/- 0.76 mg/liter after the second 400-mg infusion. Mean trough concentrations at 24 h were significantly different: 2.77 +/- 0.63 (800 mg) versus 1.93 +/- 0.49 (400 mg twice) mg/liter (P = 0.0007). Mean SBAs against E. coli after 800 mg of pefloxacin were higher than 1/128 (1 h), 1/32 (12 h), and 1/16 (24 h). Mean SBAs against S. aureus under the same conditions were higher than 1/64 (1 h), 1/16 (12 h), and 1/8 (24 h). Mean SBAs at 1 and 12 h were significantly higher after the 800-mg infusion than after the 400-mg infusion but were similar at 24 h for both regimens. Comparison of SBAs according to National Committee for Clinical Laboratory Standards criteria showed a similar adequacy at 24 h for both regimens against both strains. Administration of 800 mg of pefloxacin once a day is bioequivalent to 400 mg twice a day, and bactericidal activity of the 800-mg infusion is not less than that of two 400-mg infusions.

[Pefloxacin and cat-scratch disease]

Three patients with cat scratch diseases were treated with pefloxacin (800 mg p.d.). Three of four criteria of the diagnosis were present. The pathogen of the disease is probably an intracellular Gram negative bacilli with a deficient wall. Improvement was obtained in one case and partial response in two other cases.