Effects of sensory feedback on variations on intertap interval and force in finger-tapping sequences.

This study was designed to examine effects of somatosensory feedback on variations of intertap interval and muscle force in finger-tapping sequences over 10 minutes. Although intertap intervals were decreased on the massed task as the time passed, the intervals were constant in the distributed task. In finger-tapping for a long time, impulses perhaps circulate within the loop circuits between the cerebral motor cortex and the peripheral nerve and subsequently increase further the excitability of the circuits. This increase in the excitability within the circuits may shorten the interval and increase variation of the interval. On the other hand, although peak force increased up to the 5-min. mark on the massed task, the force decreased after the 6-min. mark. This increase of force also may be produced by increasing activation of the corticoperipheral loop circuits. Although the decrease of force was perhaps produced by the fatigue of finger muscles for tapping during a few minutes, fatigue appeared more clearly in muscle force than in timing control. However, the force and the variation were constant in the distributed task.

Progression of T cell lineage restriction in the earliest subpopulation of murine adult thymus visualized by the expression of lck proximal promoter activity.

The proximal promoter of lck directs gene expression exclusively in T cells. To investigate the developmental regulation of the lck proximal promoter activity and its relationship to T cell lineage commitment, a green fluorescence protein (GFP) transgenic (Tg) mouse in which the GFP expression is under the control of the proximal promoter of lck was created. In the adult GFP-Tg mice, >90% of CD4(+)CD8(+) and CD4(+)CD8(-) thymocytes, and the majority of CD4(-)CD8(+) and CD4(-)CD8(-) [double-negative (DN)] thymocytes were highly positive for GFP. Slightly lower but substantial levels of expression of GFP was also observed in mature splenic T cells. No GFP(+) cells was detected in non-T lineage subsets, including mature and immature B cells, CD5(+) B cells, and NK cells, indicating a preserved tissue specificity of the promoter. The earliest GFP(+) cells detected were found in the CD44(+)CD25(-) DN thymocyte subpopulation. The developmental potential of GFP(-) and GFP(+) cells in the CD44(+)CD25(-) DN fraction was examined using in vitro culture systems. The generation of substantial numbers of alphabeta and gammadelta T cells as well as NK cells was demonstrated from both GFP(-) and GFP(+) cells. However, no development of B cells or dendritic cells was detected from GFP(+) CD44(+)CD25(-) DN thymocytes. These results suggest that the progenitors expressing lck proximal promoter activity in the CD44(+)CD25(-) DN thymocyte subset have lost most of the progenitor potential for the B and dendritic cell lineage. Thus, progression of T cell lineage restriction in the earliest thymic population can be visualized by lck proximal promoter activity, suggesting a potential role of Lck in the T cell lineage commitment.

Expression of carbohydrate-binding protein p33/41 in human tumor cell lines.

We previously reported a new type of lectin, p33/41 (annexin IV), which was isolated from a bovine tissue extract [Kojima, K. et al. (1992) J. Biol. Chem. 267, 20536-20539]. When the expression of p33/41 (annexin IV) was surveyed in the lysates of 39 human tumor cell lines by SDS-PAGE, followed by Western blot analysis with polyclonal anti-bovine p33/41 and monoclonal anti-annexin IV (Z016, Zymed) antibodies, 21 cell lines were found to be reactive with the polyclonal antibody, whereas all 39 cell lines were stained with Z016. These results together with those obtained with standard proteins, annexins IV and V, suggested that the monoclonal antibody, Z016, recognizes annexin V, but not p33/41 (annexin IV). Therefore, we performed cDNA cloning of human p33/41 (annexin IV) to prepare a recombinant protein and raised monoclonal antibodies against the protein. Northern blot analysis with the cDNA as a probe showed that a human colon cancer cell line, HT29, contains p33/41 (annexin IV) mRNA of two sizes, 2.0 and 3.0 kb. The two monoclonal antibodies, AS11 and AS17, against the recombinant protein generated were useful for flow cytometric analysis, ELISA, Western blot analysis and immunoprecipitation. Flow cytometric analysis with AS17 showed that p33/41 (annexin IV) is located in the cytoplasm of HT29 cells, but not on the cell surface. However, one of the cell surface proteins first labeled with biotin and then solubilized with a detergent was immunoprecipitated with AS17. The results suggest the existence of a membrane spanning form of p33/41 (annexin IV).

Tokishakuyakusan effect on DNA polymerase alpha activity in relationship to DNA synthesis before and/or after the LH/FSH surge in rats.

DNA polymerase alpha activity in ovaries of mature cycling rats during the normal estrous cycle changed in a cyclic manner with a peak at 1800 h in proestrus. Tokishakuyakusan (TS) in vivo did not affect the changes in DNA polymerase alpha and beta activities during the estrous cycle. LH and FSH at 1000 or 1700 h in proestrus increased DNA polymerase alpha activity, but the DNA polymerase alpha activity induced by LH or FSH was not significantly affected by the addition of TS. DNA polymerase beta activity did not change with LH, FSH or TS. In PMS-treated or -untreated immature rats, TS enhanced ovarian DNA polymerase alpha activity but had no significant effect on LH or FSH action. In ovaries, incubated in vitro, in untreated mature or immature rats, TS enhanced ovarian DNA polymerase alpha activity but had no significant effect on LH or FSH action. These results suggest that TS stimulates ovarian DNA polymerase alpha activity in relationship to DNA synthesis and does not affect the effect of LH or FSH on the activity by preovulatory follicle before and/or after the LH/FSH surge.

Effects of combined therapies with protein-bound polysaccharide (PSK, Krestin) and fluorinated pyrimidine derivatives on experimental liver metastases and on the immunologic capacities of the hosts.

An experimental model is introduced for the study of liver metastases using intrasplenically injected EL-4 and Lewis lung tumor cells. Fluorinated pyrimidine derivatives, 1-(2-tetrahydrofuryl)-5-fluorouracil and 5-fluorouracil, showed inhibitory effects on the frequencies of liver metastases. Immunosuppressive effects of these drugs were compared at the doses capable of showing 50% inhibition of the development of metastatic nodules. These derivatives strongly suppressed the phagocytic activity and the number of Kupffer cells of the liver and then the humoral response against sheep red blood cells, the delayed hypersensitivity against picryl chloride. On the contrary, combined administration of protein-bound polysaccharide (PSK) and 1-(2-tetrahydrofuryl)-5-fluorouracil showed no inhibitory effect on these activities.