Limitations of the L3 skeletal muscle index and the Asian Working Group for Sarcopenia 2019 consensus diagnostic criteria for sarcopenia evaluation in a case of diffuse large B-cell lymphoma.

Sarcopenia is an adverse prognostic factor for diffuse large B-cell lymphoma. A case of diffuse large B-cell lymphoma whose diagnosis, severity, and therapeutic effect of sarcopenia were difficult to determine owing to lymphoma cell infiltration into the psoas major and femoral bone marrow is reported. At presentation, the cross-sectional area of left psoas major at L3 was enlarged owing to lymphoma cell infiltration; thus, sarcopenia evaluation was impossible by L3 skeletal muscle index. The patient was bedridden; thus, sarcopenia evaluation was impossible by the Asian Working Group for Sarcopenia 2019 consensus diagnostic criteria at presentation. At the terminal stage, she could not walk due to bilateral anterior thigh pain caused by lymphoma infiltration into femoral marrow; thus, sarcopenia evaluation was impossible by the Asian Working Group for Sarcopenia 2019 consensus diagnostic criteria. Although the L3 skeletal muscle index and the Asian Working Group for Sarcopenia 2019 consensus diagnostic criteria are representative sarcopenia evaluation systems, they cannot be used to evaluate sarcopenia in some diffuse large B-cell lymphoma patients.

Effects of extracellular matrices derived from different cell sources on chondrocyte functions.

Cell-derived extracellular matrices (ECMs) are a key factor in regulating cell functions in tissue engineering and regenerative medicine. The fact that cells are surrounded by their specific ECM in vivo elicits the need to elucidate the effects of ECM derived from different cell sources on cell functions. Here, three types of ECM were prepared by decellularizing cultured chondrocytes, fibroblasts, and mesenchymal stem cells (MSC) and used for chondrocyte culture to compare their effects on chondrocyte adhesion, proliferation, and differentiation. Chondrocyte adhesion to the chondrocyte-derived ECM was greater than those to the fibroblast- and MSC-derived ECM. Chondrocyte proliferation on the chondrocyte-derived ECM was lower than those on the fibroblast- and MSC-derived ECM. The ECM showed no evident effect on chondrocyte differentiation. The effects of ECM on cell functions depended on the cell source used to prepare the ECM.

N(epsilon)-(3-methylpyridinium)lysine, a major antigenic adduct generated in acrolein-modified protein.

Acrolein, a representative carcinogenic aldehyde, that could be ubiquitously generated in biological systems under oxidative stress shows facile reactivity with a nucleophile such as a protein. In this study, to gain a better understanding of the molecular basis of acrolein modification of protein, we characterized the acrolein modification of a model peptide (the oxidized B chain of insulin) by electrospray ionization-liquid chromatography/mass spectrometry method and established a novel acrolein-lysine condensation reaction. In addition, we found that this condensation adduct represented the major antigenic adduct generated in acrolein-modified protein. To identify the modification site and structures of adducts generated in the acrolein-modified insulin B chain, both the acrolein-pretreated and untreated peptides were digested with V8 protease and the resulting peptides were subjected to electrospray ionization-liquid chromatography/mass spectrometry. This technique identified nine peptides, which contained the acrolein adducts at Lys-29 and the N terminus, and revealed that the reaction of the insulin B chain with acrolein gave multiple adducts, including an unknown adduct containing two molecules of acrolein per lysine. To identify this adduct, we incubated N(alpha)-acetyllysine with acrolein and isolated a product having the same molecular mass as the unknown acrolein-lysine adduct. On the basis of the chemical and spectroscopic evidence, the adduct was determined to be a novel pyridinium-type lysine adduct, N(epsilon)-(3-methylpyridinium)lysine (MP-lysine). The formation of MP-lysine was confirmed by amino acid analysis of proteins treated with acrolein. More notably, this condensation adduct appeared to be an intrinsic epitope of a monoclonal antibody 5F6 that had been raised against acrolein-modified protein.