Ocular/adnexal lymphoma: dissimilar to systemic lymphoma.

Ocular adnexal lymphoma and intraocular lymphoma, whether occurring simultaneously or sequentially, are often similar to associated systemic lymphoma. We describe 4 cases of ocular adnexal lymphoma or intraocular lymphoma with a dissimilar systemic lymphoma. Two of the cases represent Richter transformation of chronic lymphocytic leukemia/small-cell lymphoma into diffuse large B-cell lymphoma. In the third patient, conjunctival extranodal marginal zone lymphoma developed following treatment for Hodgkin lymphoma. The fourth patient had a remote history of systemic diffuse large B-cell lymphoma with a subsequent diagnosis of orbital extranodal marginal zone lymphoma. Clinical-pathological correlation is reported for all cases in addition to pertinent review of the literature.

Rotational-echo double resonance characterization of the effects of vancomycin on cell wall synthesis in Staphylococcus aureus.

Cross-polarization magic-angle spinning and rotational-echo double resonance 13C and 15N NMR experiments have been performed on intact cells of Staphylococcus aureus labeled with D-[1-13C]alanine and [15N]glycine or with [1-13C]glycine and L-[epsilon-15N]lysine. The cells were harvested during stationary or exponential growth conditions, the latter in media with and without the addition of vancomycin. The results of these experiments allowed the in situ determination of the relative concentrations of peptidoglycan cross-links (the number of peptide-stem D-alanines covalently linked to a pentaglycyl bridge) and bridge-links (the number of peptide-stem lysines covalently linked to a pentaglycyl bridge). The concentration of cross-links remained constant in the presence of vancomycin, whereas the number of bridge-links decreased. These changes suggest that vancomycin (at therapeutic levels) interrupts peptidoglycan synthesis in S. aureus by interference with transglycosylation.