Impact of ceftazidime restriction on gram-negative bacterial resistance in an intensive care unit

The present study included three periods: (1) a 12-month prerestriction and control period in 2001; (2) a 12-month restriction period with reduced ceftazidime prescribing in favor of piperacillin-tazobactam (2002); (3) and a 24 month postrestriction period (2003–2004). Note that, for results, P represents the difference between 2002 and 2001; P′, the difference between 2003 and 2001; and P″, the difference between 2004 and 2001. No changes in hygiene practices were observed during these three periods. The purpose of this study was to assess the effect of reducing ceftazidime use in an intensive care unit (ICU) upon Gram-negative bacterial resistance, particularly as regards Pseudomonas aeruginosa. During the three periods of the study, patients were similar concerning age, Simplified Acute Physiology Score (SAPSII), the site of nosocomial infection, and the requirements for mechanical ventilation (75% in 2001, 76% in 2002, 74% in 2003, and 85% in 2004). The most commonly isolated pathogens were P. aeruginosa, Acinetobacter baumannii, and Enterobacteriaceae. The use of ceftazidime decreased significantly from 12.6% in 2001 to 9% in 2002, to 3% in 2003 (P′ = 0.0009), and 2.6% in 2004 (P″ = 0.0001) in favor of piperacillin-tazobactam (0% 2001 to 3.7% in 2003; P′ = 0.002; and 5% in 2004; P″ = 0.0001). Simultaneously, we observed a significant decrease in isolates of P. aeruginosa resistant to piperacillin-tazobactam (P = 0.03; P′ = 0.004; P″ = 0.009), and those resistant to imipenem in 2003 (P′ = 0.008). We also noted a significant decrease in A. baumannii isolates resistant to ceftazidime (P′ = 0.01; P″ = 0.0004) and those resistant to imipenem in both 2002 and 2004 (P = 0.03; P″ = 0.04), and a considerable decrease in isolates of Klebsiella pneumoniae producing expanded spectrum betalactamase (ESBL) in 2003 and 2004 (P′ = 0.04; P″ = 6.10⁻⁵). In contrast, we noted an increase in penicillinase-producing isolates of K. pneumoniae, from 6% in 2001 to 16% in 2002 (p = 0.01), 20% in 2003 (P′ = 0.001), and 32% in 2004 (P″ = 10⁻⁶). We concluded that restriction of ceftazidime use was demonstrated to be efficient in reducing antimicrobial resistance, especially to K. pneumoniae ESBL.     

Impaired helix 12 dynamics due to proline 892 substitutions in the androgen receptor are associated with complete androgen insensitivity

Human Molecular Genetics (2006) 15, 921–931;     

Enantioselective metabolism and cytotoxicity of R-ifosfamide and S-ifosfamide by tumor cell-expressed cytochromes P450.

The anticancer prodrug ifosfamide (IFA) contains a chiral phosphorous atom and is administered in the clinic as a racemic mixture of R-IFA and S-IFA. Hepatic cytochrome P450 (P450) enzymes exhibit enantioselective preferences in the metabolism of R-IFA and S-IFA; however, the impact of this selectivity on P450-dependent anticancer activity is not known. Presently, the metabolism and cytotoxicity of R-IFA and S-IFA were determined in 9L gliosarcoma and Chinese hamster ovary tumor cells expressing an IFA-activating P450 enzyme and by in vitro steady-state kinetic analysis using cDNA-expressed P450 enzymes. Tumor cells expressing P450 enzyme CYP3A4 were the most sensitive to R-IFA cytotoxicity, whereas tumor cells expressing CYP2B1 or CYP2B6 were most sensitive to cyclophosphamide (CPA), an isomer of IFA. Correspondingly, CYP3A4-expressing cells and cDNA-expressed CYP3A4 metabolized R-IFA to yield the active, 4-hydroxylated metabolite at a 2- to 3-fold higher rate than they metabolized S-IFA or CPA. CYP2B cells and cDNA-expressed CYP2B enzymes metabolized CPA almost exclusively by 4-hydroxylation, whereas R-IFA and S-IFA were substantially converted to inactive, N-dechloroethylated metabolites. Further investigation revealed that CYP3A1, a rat enzyme, exhibited superior kinetic properties compared with the human enzyme CYP3A4, with R-IFA and S-IFA both metabolized with high catalytic efficiency by 4-hydroxylation and with a K(m) value of 200 microM, approximately 5-fold lower than CYP3A4. Based on these kinetic parameters and metabolic profiles, R-IFA is expected to exert greater anticancer activity than S-IFA or CPA against tumors that express CYP3A enzymes, whereas tumors expressing CYP2B enzymes may be more sensitive to CPA treatment.     

False-Positive Computed Tomographic Findings in a Series of 525 Patients with Acoustic Neuromas

In our series of 525 patients operated on for acoustic neuroma, there were three false-positive computed tomography findings resulting in unnecessary surgery. The histories and results of laboratory investigations and surgery are presented. Discussion of the outcome had gadolinium-enhanced magnetic resonance imaging been performed is presented.     

Cetirizine dihydrochloride interaction with some diclofenac complexes.

IR, 1H NMR and mass spectrometric studies showed that cetirizine dihydrochloride interacted strongly with diclofenac sodium, even when the latter was metal bound, forming high molecular weight stable adducts. These new formations were unaffected by the possible steric constraints that may exist because of coordination yet did not have the power to break the formed coordinate bonds. The formed ionic bond took place between the carbonyl ion of diclofenac and the positively charged piperazine ring of cetirizine, forming a ternary compound in the case of the divalent metal clusters (Ca{(dic)2.2H2O}, Mg{(dic)2.2H2O}, Zn{(dic)2.2H2O}) and a quaternary one with the trivalent iron cluster (Fe{dic}3.3H2O). IR bands assigned to nuNH, deltaNH and nuC-N were shifted to lower frequency values in the spectra of the complexes; thus showing that coordination took place at the NH of the diphenylamine. TG and elemental analysis confirmed these results.     

The effect of naloxone on the preoperative gastric volume and pH

The effect of 4 mg oral naloxone on preoperative gastric volume and pH of gastric aspirate was studied in a double-blind, randomized study. Twenty patients received 10 ml of naloxone (4 mg) mixed with 10 ml of orange juice, and 20 patients received 10 ml of isotonic saline mixed with 10 ml of orange juice, 2 h before surgery. Gastric content was obtained immediately after intubation of the trachea. No significant difference in gastric volume and pH of gastric aspirate was found between the two groups. It is concluded that naloxone does not affect gastric emptying and gastric acid secretion to a degree great enough to protect against aspiration of gastric contents into the lungs.