Adaptations of Vancomycin-Intermediate Sequence Type 72 Methicillin-Resistant Staphylococcus aureus for Daptomycin Nonsusceptibility.

In Korea, the major clonal type of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is sequence type 72 (ST72) with staphylococcal cassette chromosome mec (SCCmec) type IV (ST72-MRSA-IV). In this study, we used a previously well-characterized isogenic pair of ST72 vancomycin (VAN) susceptible-and VAN intermediate-MRSA strains (VSSA303 and VISA072) and several VSSA strains complemented with plasmids expressing single-point mutated genes (dprAG196C, femAF92C, vraRE127K, and vraSRE127K) identified in the VISA strain. Using the strain set, we assessed the (1) susceptibilities to daptomycin (DAP) and cationic antimicrobial peptides (CAMPs), (2) alterations in cell envelope phenotypes, such as cell wall autolysis, surface positive charge, and membrane potential (ΔΨ), (3) transcriptional expression profiles of genes involved in surface charge regulation and changes of ΔΨ, and (4) cytokine stimulation profiles in murine macrophages. The vraRE127K mutation could enhance surface positive charge through mprF- and dltABCD-independent mechanisms with thickened cell wall. However, none of the single-point mutated genes increased DAP resistance. The DAP nonsusceptible (DAP-NS) phenotype observed in VISA072 strain likely resulted from the combined effects of low ΔΨ and increased positive surface charge. These results suggest that physicochemical alterations in cell envelope are involved in the survival response of DAP-NS VISA072 in sites of infections.

Transit time corrected arterial spin labeling technique aids to overcome delayed transit time effect.

PURPOSE: This study aimed to evaluate the usefulness of transit time corrected cerebral blood flow (CBF) maps based on multi-phase arterial spin labeling MR perfusion imaging (ASL-MRP). METHODS: The Institutional Review Board of our hospital approved this retrospective study. Written informed consent was waived. Conventional and multi-phase ASL-MRPs and dynamic susceptibility contrast MR perfusion imaging (DSC-MRP) were acquired for 108 consecutive patients. Vascular territory-based volumes of interest were applied to CBF and time to peak (TTP) maps obtained from DSC-MRP and CBF maps obtained from conventional and multi-phase ASL-MRPs. The concordances between normalized CBF (nCBF) from DSC-MRP and nCBF from conventional and transition time corrected CBF maps from multi-phase ASL-MRP were evaluated using Bland-Altman analysis. In addition, the dependence of difference between nCBF (ΔnCBF) values obtained from DSC-MRP and conventional ASL-MRP (or multi-phase ASL-MRP) on TTP obtained from DSC-MRP was also analyzed using regression analysis. RESULTS: The values of nCBFs from conventional and multi-phase ASL-MRPs had lower values than nCBF based on DSC-MRP (mean differences, 0.08 and 0.07, respectively). The values of ΔnCBF were dependent on TTP values from conventional ASL-MRP technique (F = 5.5679, P = 0.0384). No dependency of ΔnCBF on TTP values from multi-phase ASL-MRP technique was revealed (F = 0.1433, P > 0.05). CONCLUSION: The use of transit time corrected CBF maps based on multi-phase ASL-MRP technique can overcome the effect of delayed transit time on perfusion maps based on conventional ASL-MRP.

Four cases of non-Hodgkin's lymphoma in AIDS patients.

The incidence of opportunistic infection has decreased since the introduction of highly active antiretroviral therapy, so lymphoma is now far and away the most lethal complication of acquired immunodeficiency syndrome. We have experienced four cases of NHL in AIDS patients. The first patient was a 37 year old male who presented with left sided hemiplegia due to CNS lymphoma. The second patient was a 40 year old male who was admitted because of jaundice; he was diagnosed as having lymphoma that exclusively involved the liver. The third patient was a 38-year-old male who presented with palpable mass in the left cervical region, which was diagnosed as lymphoma. Above three cases were confirmed as diffuse large B cell lymphoma. The fourth patient presented with a protruding swollen chest wall mass on the right side of his chest, this was determined pathologically to be the Burkitt's type. The latter case is the first report of NHL involving the chest wall musculature in a Korean AIDS patient.

[A case of primary hepatic lymphoma mimicking hepatitis].

We report here on a case of non-Hodgkin's lymphoma in which liver involvement was the predominant clinical manifestation. A healthy 44-year-old man presented with upper abdominal pain, hepatosplenomegaly, thrombocytopenia, elevated AST, ALT and bilirubin, and marked elevation of lactate dehydrogenase and alkaline phosphatase. The abdominal CT scan showed only diffuse hepatosplenomegaly and uneven contrast enhancement of the spleen without any definite mass of the liver and spleen. US-guided aspiration biopsy of liver and the histologic examination confirmed a diagnosis of non-Hodgkin's lymphoma, the diffuse large B cell type. Bone marrow biopsy showed the infiltration of malignant lymphoma cells. PET-CT showed an increased FDG uptake of the liver, spleen and long bones. The patient was treated with combination regimen of cyclophosphamide, doxorubicin, vincristine and prednisone chemotherapy. Even in the absence of a mass lesion or lymphadenopathy, primary hepatic or hepatosplenic lymphoma should be considered in differential diagnosis of hepatitis or liver cirrhosis, especially for patients with diffuse hepatosplenomegaly and markedly elevated LDH.