A novel approach for characterization of KSHV-associated multicentric Castleman disease from effusions

A biopsy of lymphoid tissue is currently required to diagnose Kaposi sarcoma-associated herpesvirus (KSHV)-associated multicentric Castleman disease (KSHV–MCD). Patients showing clinical manifestations of KSHV–MCD but no pathological changes of KSHV–MCD are diagnosed as KSHV inflammatory cytokine syndrome. However, a lymph node biopsy is not always feasible to make the distinction. A pathognomonic feature of lymph nodes in KSHV–MCD is the expansion of KSHV-infected, lambda-restricted but polyclonal plasmablasts. To investigate whether these cells also reside in extra-nodal sites, effusion from 11 patients with KSHV–MCD and 19 with KSHV inflammatory cytokine syndrome was analysed by multiparametric flow cytometry. A distinct, lambda-restricted plasmablastic population (LRP) with highly consistent immunophenotype was detected in effusions in 8/11 patients with KSHV–MCD. The same population was also observed in 7/19 patients with KSHV inflammatory cytokine syndrome. The detection of LRP stratified KSHV inflammatory cytokine syndrome into two clinically distinct subgroups; those with detectable LRP closely resembled KSHV–MCD, showing similar KSHV viral load, comparable severity of thrombocytopenia and hypoalbuminaemia, and similar incidences of hepatosplenomegaly. Collectively, the detection of LRP by flow cytometry can serve as a valuable tool in diagnosing KSHV–MCD. KSHV inflammatory cytokine syndrome with LRP in effusions may represent a liquid-form of KSHV–MCD.     

Alkylation of DNA with aziridine produced during the hydrolysis of N,N',N'-triethylenethiophosphoramide.

A reaction pathway by which thiotepa (N,N',N'-triethylenethiophosphoramide) and tepa (N,N',N'-triethylenethiophosphoramide), its major metabolite in humans, alkylate and depurinate DNA involves hydrolysis to aziridine (ethylene imine), a highly reactive monofunctional alkylating agent. Hydrolytic cleavage of an N-P bond of thiotepa releases aziridine which reacts with DNA, resulting in depurination and formation of the stable N-7 adduct 7-(2-aminoethyl)guanine and an aminoethyl adduct of adenine. Chromatographically identical alkylated products were observed in the reaction of thiotepa and tepa with individual nucleosides. Adducts with deoxycytidine or thymidine were not detected. Aziridine was measured by HPLC after derivatization with 1,2-naphthoquinone 4-sulfate. On the basis of the identity of the DNA adducts and the rate of formation of aziridine by hydrolysis in vitro, thiotepa is concluded to be a lipophilic, stabilized form of aziridine which serves as a cell-penetrating carrier of aziridine.     

Yttrium-90 therapy and 99MTc pertechnetate knee uptake measurements in the management of rheumatoid arthritis.

Twenty-eight knees with chronic arthritis and effusion were treated with intra-articular 90Y. Synovial activity was assessed by measuring 99mTc pertechnetate uptake. There was a significant difference in uptake between controls and patients. Those who had a good response to 90Y (15 patients) showed a significant decrease in uptake, not seen in those who failed to respond. The pattern of 90Y distribution was examined and appeared to correspond to areas of increased synovial activity; these patterns and their significance have not been previously reported. Factors which could help to predict response to 90Y are discussed.     

Metabolism of acetaminophen by cultured rat hepatocytes. Depletion of protein thiol groups without any loss of viability

Over the course of 4 hr, the metabolism of acetaminophen (APAP) by cultured rat hepatocytes resulted in a depletion of protein thiols and an accumulation of oxidized glutathione (GSSG) in the medium. With 20 mM APAP, arylation and the formation of glutathione mixed disulfides accounted for a loss of 22% of the total protein thiols in the absence of any loss of viability. With 20 mM APAP and an inhibition of glutathione reductase by 1.3-(2-chloroethyl)-1-nitrosourea (BCNU), protein thiols were depleted by 40% by arylation and the formation of glutathione mixed disulfides, again without a loss of viability. With 20 mM APAP and BCNU in the presence of 20 mM deferoxamine, there was still little or no cell killing after 8 hr despite a loss now of almost 60% of the total protein thiols. These data do not support the hypothesis that a depletion of protein thiols is related to the toxicity of APAP. One millimolar APAP and BCNU killed 60% of the hepatocytes within 4 hr. In this circumstance, the loss of protein thiols was not attributable to either arylation by APAP metabolites or the formation of glutathione mixed disulfides. The antioxidant N,N'-diphenyl-phenylenediamine prevented the cell killing and the loss of protein thiols, a result implicating a role for lipid peroxidation in the depletion of protein-bound thiols. However, protein thiol depletion under these circumstances is not necessarily related to the lethal cell injury and most likely represents an epiphenomenon of the peroxidation of cellular lipids.