Myeloma cells produce sialyl salivary-type amylase

Synthetic studies of bi-fluorescence-labeled maltooligosaccharides as substrates for α-amylase on the basis of fluorescence resonance energy transfer (FRET)

A series of bi-fluorescence-labeled maltooligosaccharides that lead to fluorescence resonance energy transfer (FRET) was systematically synthesized. Effective FRETs were observed with all of the synthesized probes. Digestion of probes having tetra-, quintet-, hexa- or hepta-saccharidic chain lengths with human saliva α-amylase resulted in disappearance of FRET when an excitation wavelength of at 290nm was used followed by detection at ca. 520nm due to emission from the dansyl moiety. However, continuous FRET was observed when probes having di- or trisaccharidic chain lengths were used as substrates. In addition to the substrate characteristics based on saccharidic chain length, the reaction rates of digestion for the substrates by amylase were different and also depended on their saccharidic chain length.

Simple and conveniently accessible bi-fluorescence-labeled substrates for amylases

Synthesis of bi-fluorescence-labeled maltooligosaccharides for amylase assay was accomplished. Preliminary biological evaluation of both bi-fluorescence-labeled maltohexasaccharide and maltose using alpha-amylase was carried out, and the hexaosyl derivative showed unique variation on the basis of fluorescence resonance energy transfer (FRET).

Multiple myeloma associated with sialyl salivary-type amylase

BACKGROUND

There have been several reports describing a notable hyperamylasaemia in patients with multiple myeloma. Such amylase-producing myelomas have been mainly described in the context of concomitant salivary-type hyperamylasaemia, with sialyl salivary-type amylase identified in a portion of those cases. We investigated the incidence of the production of sialyl salivary-type amylase in serum of multiple myeloma patients.

METHODS

Eleven patients (6 male and 5 female) who had been diagnosed as having multiple myeloma were enrolled in this study. Sialyl salivary-type amylase was detected by isoamylase electrophoresis and HPLC analysis, and identified by detecting either abnormal neuraminidase-sensitive band through isoamylase electrophoresis or abnormal extra-elution peak of amylase by means of HPLC analysis.

RESULTS

Sialyl salivary-type amylase was detected in 7 out of 11 (63.6%) patients. Median total amylase activity was 154 U/l (range 109-43020). Isoamylase electrophoretic patterns of patients' serum were normal in 5 patients (71.4%) out of 7 patients and salivary-dominant in 2 (50.0%) out of 4 patients.

CONCLUSIONS

We consider that there is no significant relationship between total serum amylase level and amylase isoenzyme pattern in the incidence of production of sialyl salivary-type amylase with multiple myeloma.

Paraneoplastic hyperamylasaemia in association with multiple myeloma

Marked hyperamylasaemia associated with an amylase-producing multiple myeloma appears to be a fairly unusual phenomenon. The present report describes a fatal case of multiple myeloma associated with paraneoplastic hyperamylasaemia without evidence of pancreatic or salivary gland involvement. Serum and urine amylase levels paralleled the myeloma response to chemotherapy and disease progression. The importance of paraneoplastic hyperamylasaemia as a useful myeloma marker to monitor disease progression and treatment response is emphasized. Conventional chemotherapy at diagnosis and salvage treatment with bortezomib at relapse failed to achieve a long-term response and to decrease the serum amylase to a normal level.