Endometrioid carcinoma in pelvic endometriosis in a postmenopausal woman with tamoxifen adjuvant therapy for breast cancer. A case report.

This concerns a 57 year old woman operated on in 1988 for a left radical mastectomy due to ductal breast carcinoma and subsequently treated with chemotherapy and Tamoxifen adjuvant. In 1990 a laparo-hystero-oophorectomy was carried out due to uterine fibromas. The woman continued taking Tamoxifen. Two years later a pelvic regeneration appeared, resulting in endometriosis, site of adenomatose hyperplasia and of endometrioid carcinoma GI. This furthermore confirms the importance of a gynecological follow-up for all women treated with Tamoxifen adjuvant therapy.

[Uptake of ofloxacin by Escherichia coli]. / Pénétration de l'ofloxacine chez Escherichia coli.

The uptake of ofloxacin by Escherichia coli NIHJ-JC2 was determined by a sensitive and convenient method using high-performance liquid chromatography (HPLC) with a fluorometric detection (sensitivity level: 1 ng/ml). Concentrations of ofloxacin were measured in bacteria after contact with 5 micrograms/ml of antibiotic for 1, 2, 3, 5, 10, 20 and 30 min. Ofloxacin uptake was rapid, 70% of broth concentration occurring within the first min and 96% after 5 min; then it reached a plateau which was 1.16 times as high as the broth concentration.

Competitive interactions of drugs with their targets: a computerized improvement of Dixon's algorithm.

Many drugs are competitive and reversible enzyme inhibitors. When the target enzyme kinetics follows the Michaelis-Menten equation, the enzyme affinity of the inhibitor is characterized by a single parameter: the Ki value. This parameter is usually determined via Dixon's procedure: (i). the rate of reaction (V) is measured in the presence of a few concentrations of the inhibitor (I); (ii.) 1/V versus I gives a straight line, which allows a graphic determination of the inhibitory constants, or better via a least-square fit the linear regression. The introduction of appropriate weighting factors in the linear regression may improve the accuracy of the Ki determinations.

Structural features related to hydrolytic activity against ceftazidime of plasmid-mediated SHV-type CAZ-5 beta-lactamase.

Tryptic peptides of the novel ceftazidimase CAZ-5 were sequenced by manual Edman degradation and aligned according to strong homology (more than 98%) with SHV-1 and SHV-2 beta-lactamase sequences. CAZ-5 differed from SHV-1 by five amino acid substitutions. Unusually high activity of CAZ-5 towards ceftazidime was imputed to substitution of a Lys for a Glu at position 214 of the mature protein.

Sulbactam: biochemical factors involved in its synergy with ampicillin.

Sulbactam is a time-dependent irreversible inhibitor of various beta-lactamases by reversible formation of a Michaelis-type enzyme-inhibitor complex and progressive evolution of this complex into inactivated protein(s). This process is either irreversible (true inactivation) or quasi-irreversible (stable acyl-enzyme). In this way, sulbactam efficiently protects ampicillin from degradation by beta-lactamases. Sulbactam itself exhibits a moderate antibacterial activity that is related to an affinity for the penicillin-binding proteins of various bacterial strains, which is similar to the affinity of penicillins such as ampicillin. However, sulbactam binding differs according to the bacterial species involved. In strains producing either low levels of beta-lactamase or none at all, a synergistic effect, minor but not negligible, can be observed when sulbactam is associated with a beta-lactam antibiotic with a complementary affinity for the target sites.