Immunofluorescent and biochemical studies on tyrosine hydroxylase and dopamine-β-hydroxylase of the bullfrog sciatic nerves

Summary Immunofluorescence specific for tyrosine hydroxylase (TH) or dopamine--hydroxylase (DBH) was accentuated in both proximal and distal segments of the sciatic nerve after ligation. Estimations of the enzyme activities confirmed the above results. Mean axoplasmic flow rates of TH and DBH in bullfrog sciatic nerve were found to be 8 and 123 mm/day, respectively. They were decreased by colchicine or by cold temperatures (4° C).     

A novel strategy for the negative selection in mouse embryonic stem cells operated with immunotoxin-mediated cell targeting.

Immunotoxoin-mediated cell targeting (IMCT) is a technique for conditionally ablating specific cell types based on the cytotoxic activity of a recombinant immunotoxin anti-Tac (Fv)-PE40. To examine the feasibility of this technique for the negative selection in mouse embryonic stem (ES) cells, we investigated the responsiveness of cells expressing human interleukin-2 receptor alpha subunit to anti-Tac(Fv)-PE40. The immunotoxin treatment efficiently eliminated only ES cells bearing the receptor as a consequence of the target specificity of anti-Tac(Fv)-PE40, indicating that IMCT can be used as a novel strategy for positive and negative selection to enrich ES cell clones with a targeted mutation.     

Activities of dipeptidyl peptidase II, dipeptidyl peptidase IV, prolyl endopeptidase, and collagenase-like peptidase in synovial membrane from patients with rheumatoid arthritis and osteoarthritis.

We examined the activities of peptidases in the synovial membrane from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Dipeptidyl peptidase II (DPP II), prolyl endopeptidase (PEP), and collagenase-like peptidase (CLP) activities were higher in knee joint synovial membrane from patients with RA than in that from patients with OA. DPP II and PEP activities in knee joint synovial membrane of patients with RA increased in parallel with the increase in joint fluid volume, whereas DPP IV activity decreased in parallel with the increase in joint fluid volume. These results suggest that these peptidases in the synovial membrane may play some role in immunological disturbances in the joints of patients with RA. Measurement of these peptidases in synovial membrane may be useful in the diagnosis of the severity of local joint inflammation.     

Successive cleavage of N-terminal Arg1--Pro2 and Lys3-Pro4 from substance P but no release of Arg1-Pro2 from bradykinin, by X-Pro dipeptidyl-aminopeptidase

X-Pro dipeptidyl-aminopeptidase (EC 3.4.14.1) purified homogeneously from the human submaxillary gland was proved to hydrolyze N-terminal dipeptide Arg1-Pro2 and subsequent dipeptide Lys3-Pro4 from substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-gly-Leu-Met-NH2). Km and V values of hydrolysis of substance P were 2.0 mM and 3.6 mumol/min per mg protein, respectively. In contrast, the N-terminal Arg-Pro of bradykinin (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) was not cleaved by the enzyme.