Interaction of imipenem with erythromycin and tetracycline assessed by microdilution checkerboard techniques.

Microdilution methodology was used to study the interaction of imipenem with erythromycin and tetracycline, a combination therapy that might be used for the treatment of serious pelvic inflammatory disease. The combination of imipenem and erythromycin showed no antagonism for Escherichia coli and Haemophilus influenzae but was antagonistic for Staphylococcus aureus, Enterococcus faecalis, and group B streptococci; the combination of imipenem and tetracycline was antagonistic for all strains except H. influenzae. Correlation between the results of kill curves and the measurement of fractional bactericidal concentration (FBC) indices was good, although FBC indices showed less antagonism than kill curves. Fractional inhibitory concentration indices showed poor correlation, rarely showing antagonism, and indeed showed synergy in three cases. If erythromycin or tetracycline is considered necessary in addition to imipenem in the treatment of pelvic inflammatory disease, it is probably more effective when given after the course of imipenem has been completed.     

Ultrasonography in slipped capital femoral epiphysis. Diagnosis and assessment of severity

We used ultrasonography to study 26 hips with slipped capital femoral epiphyses. In recently slipped epiphyses the ultrasound image revealed a step at the anterior physeal outline (mean 6.4 mm), diminished distance between the anterior acetabular rim and the femoral metaphysis (mean 4.3 mm) and an effusion. As metaphyseal remodelling progressed the physeal step decreased. The femoral neck appeared straighter in hips which had been symptomatic for longer than three weeks. It was possible to measure posterior epiphyseal displacement without projectional errors and the method was accurate in diagnosing minimal slip and in staging displacement. The suggested criteria are, less than 7 mm for a mild slip, 7 to 11 mm for a moderate slip and more than 11 mm for a severe slip. We recommend ultrasonography for the diagnosis, staging and follow-up management of slipped upper femoral epiphysis.     

Haemophilus influenzae subtyping by SDS-PAGE of whole-cell polypeptides

Strains of Haemophilus influenzae isolated from patients in N.E. Scotland between 1983 and 1986 have been subtyped by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell polypeptides. Gels were stained with Coomassie blue and polypeptide profiles were analysed using the Dice coefficient of similarity. Type b strains were all closely related, the 19 strains analysed being grouped at a 90% similarity level into one large (13 strains) and one small (3 strains) cluster with 3 strains being ungrouped. Thirty-six non-typable, epidemiologically unrelated strains were subtyped; one pair of strains had indistinguishable polypeptide profiles. The polypeptide profiles of the remaining strains showed much heterogeneity, although groups of strains isolated from the same patient over short periods showed indistinguishable profiles.     

Mutagenicity and toxicity studies of several α,β-unsaturated aldehydes in the Salmonella typhimurium mutagenicity assay

α,β-Unsaturated aldehydes are reactive compounds which are ubiquitous in the environment. This class of compounds has been tested for mutagenicity in Salmonella typhimurium by a number of groups who have obtained differing results. The present studies were undertaken to test the mutagenicity and toxicity of two novel α,β-unsaturated aldehydes, specifically trans,trans-muconaldehyde and trans-4-hydroxynonenal, and to re-examine the mutagenicity of crotonaldehyde. Trans,trans-muconaldehyde is a newly found microsomal metabolite of benzene, and trans-4-hydroxynonenal is a toxic aldehyde formed endogenously during lipid peroxidation. Compounds were tested in S. typhimurium strain TA 100 using a 30-min liquid preincubation procedure. The present mutagenicity studies indicate that these α,β-unsaturated aldehydes at first appear to be mutagenic, although only at concentrations which decrease survival counts, and result in a disappearance of the bacterial lawn. The colonies observed on mutagenicity test plates are not mutants but rather pin point survivors.     

Combining factors on protein and gene level to predict radioresponse in head and neck cancer cell lines

J Oral Pathol Med (2011) 40 : 739–746 Background: Radiotherapy is the main therapy for head and neck squamous cell carcinoma (HNSCC); however, treatment resistance and local recurrence are significant problems, highlighting the need for predictive markers. In this study, we evaluated selected proteins, mutations, and single nucleotide polymorphisms (SNPs) involved in apoptosis, cell proliferation, and DNA repair alone or combined as predictive markers for radioresponse in 42 HNSCC cell lines. Methods: The expression of epidermal growth factor receptor, survivin, Bax, Bcl‐2, Bcl‐X_L, cyclooxygenase‐2 (COX‐2), and heat shock protein 70 was analyzed by ELISA. Furthermore, mutations and SNPs in the p53 gene as well as SNPs in the MDM2, XRCC1, and XRCC3 genes were analyzed for their relation to radioresponse. To enable the evaluation of the predictive value of several factors combined, each cell line was allocated points based on the number of negative points (NNP) system, and the NNP sum was correlated with radioresponse. Results: Survivin was the only factor that alone was significantly correlated with the intrinsic radiosensitivity (IR; r = 0.36, P = 0.02). The combination of survivin, Bax, Bcl‐2, Bcl‐X_L, COX‐2, and the p53 Arg72Pro polymorphism was found to most strongly correlate with radioresponse (r = 0.553, P < 0.001). Conclusion: These data indicate that the IR of 42 HNSCC cell lines can be predicted by a panel of factors on both the protein and gene levels. Moreover, among the investigated factors, survivin was the most promising biomarker of radioresponse.