Fig. 1

Diagnostic findings of multiple myeloma in the cat. A Monoclonal gammopathy as assessed by agarose gel serum protein electrophoresis. B Left panel: serum protein analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis with Coomassie brilliant blue staining. Bands at ~ 59 kDa (the size of the immunoglobulin heavy chain) and ~ 27 kDa (the size of the immunoglobulin light chain) are indicated by black and white arrowheads, respectively. Specifically, in contrast to normal cat serum, serum from the cat with multiple myeloma provided a more intense band at ~ 27 kDa, and a fainter band at ~ 59 kDa. Right panel: western blotting analysis of serum (normal and patient) and patient urine using anti-feline gamma immunoglobulin (heavy and light chain) antibody. Immunoreactive bands were detected at ~ 59 kDa (black arrowhead; immunoglobulin heavy chain) and ~ 27 kDa (white arrowhead; immunoglobulin light chain) in sera from both normal and patient, confirming that the bands in the left panel (~ 59 kDa and ~ 27 kDa) were immunoglobulin heavy chain and light chain, respectively. An immunoreactive band at ~ 27 kDa (white arrowhead, Bence-Jones protein) and a weak band at ~ 59 kDa (black arrowhead, immunoglobulin heavy chain) were detected in patient urine. C Bone marrow smear stained with Wright-Giemsa (400x in left panel and 1000x in middle and right panels). Atypical plasma cell infiltration in the bone marrow was observed. Left panel: anisocytosis and anisokaryosis of plasma cells; middle panel: plasma cells with bizarrely shaped nucleus; right panel: binucleated plasma cell, plasma cells with visible nucleoli, and plasma cell with Russell body-like inclusions. Bars: left panel, 20 μm; middle and right panels, 10 μm. Equipment: microscope, Olympus BX50; objective lenses, Olympus UPlanFl 40x/0.75 and UPlanFl 100x/1.30 oil; image acquisition system, Olympus DP12