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Kenichiro Katsura

Publications and source records attributed to Kenichiro Katsura.

4 recordsLinked to original sources
PubMed2005

Milk growth factor (MGF)-induced differentiation of NT2/D1 cells.

The differentiation activity of milk growth factor (MGF, 200 ng/ml), which also has proliferative activity, was investigated in NT2/D1 cells relative to that of retinoic acid (RA, 10(-7) M). MGF suppressed the proliferation of NT2/D1 cells to the same extent as RA after cultivation for 2x4 days. MGF enhanced Fas expression in NT2/D1 cells and prevented the decrease of Fas expression when RA was also added. MGF induced the synthesis of alpha-smooth muscle actin (alpha-SM-actin) in NT2/D1 cells without fibrils, but RA did not have such a potent activity. MGF extended glial fibrillary acidic protein (GFAP) that existed in a local area of NT2/D1 cell cytoplasm. On the other hand, RA enhanced GFAP expression and dispersed it throughout the cells. MGF slightly induced neurofilament-medium size (NF-M) synthesis in NT2/D1 cells that RA induced in the cells. MGF was less effective than RA in stimulating the synthesis of epinephrine in the cells, and the additive effect of MGF and RA enhanced epinephrine synthesis. While dopamine synthesis was less effectively stimulated by MGF than by RA, an additive effect of MGF and RA for dopamine synthesis was not observed in the cells. It was thus found that MGF differentiated NT2/D1 cells through alpha-SM-actin-synthesis.

Cell Differentiation↗
PubMed2003

[Post-stroke depression].

The frequency of post-stroke depression (PSD) was evaluated in an ischemic stroke cohort four weeks after onset, and the relationship between self-rating depression scale (SDS)/and infarct size, number and location of the ischemic brain lesions was also studied. The effects of a newly developed antidepressant SSRI (selective serotonin reuptake inhibitor), fluvoxamine maleate, on PSD and cerebral blood flow (CBF) was investigated in other ischemic stroke patients. The frequency of patients who had more than 40 on SDS score was 46% (18/39), and that of patients who had more than 50 was 13% (5/39). There were no differences in SDS score in infarct size, number and location of ischemic brain lesions, however there were significant differences in the lesion side. The score of the patients who had lesions in the left hemisphere was significantly higher than that of those who had them in the right. Administration of fluvoxamine maleate for four weeks improved the score on the Hamilton rating scale for depression (HAM-D) from 16.6 +/- 4.7 (n = 5) to 8.4 +/- 4.3 (n = 5), however it did not influence the mean cortical CBF. This study shows that the patients frequently had depression after ischemic stroke, and that left side lesion had a significant relationship with PSD. Therefore it is important that psychiatric examination of post-stroke patients is conducted. This study also shows that a newly developed antidepressant, fluvoxamine maleate, was effective for PSD.

Aged↗
PubMed1992

Extra- and Intracellular pH in the Brain During Ischaemia, Related to Tissue Lactate Content in Normo- and Hypercapnic rats.

The objective of the present study was to assess the relationship between the amount of lactate accumulated during complete ischaemia and the ensuing changes in extra- and intracellular pH (pHe and pHi, respectively). The preischaemic plasma glucose concentration of anaesthetized rats was varied by administration of glucose or insulin, pHe was determined in neocortex with ion-sensitive microelectrodes, and tissue lactate and CO2 contents were measured, tissue CO2 tension being known from separate experiments. The experiments were carried out in both normocapnic [arterial CO2 tension (PaCO2) approximately 40 mm Hg] and hypercapnic (PaCO2 approximately 80 mm Hg) animals. Irrespective of the preischaemic CO2 tension, DeltapHe was linearly related to tissue lactate content. Depending on the preischaemic glucose concentration, DeltapHe varied from <0.4 to >1.4 units. The results thus fail to confirm previous results that the changes in pHe describe two plateau functions (DeltapHe approximately 0.5 and 1.1, respectively), with a transition zone at tissue lactate contents of 17 - 20 mmol kg-1. Changes in pHi given in this study are based on the assumption of a uniform intracellular space. The pHi changed from a normal value of approximately 7.0 to 6.5, 6.1 and 5.8 at tissue lactate contents of 10, 20 and 30 mmol kg-1. The intrinsic (non-bicarbonate) buffer capacity, derived from these figures, was 23 mmol kg-1 pH-1. Some differences in pH and in HCO3- concentration between extra- and intracellular fluids persisted in the ischaemic tissue. These differences were probably caused by a persisting membrane potential in the ischaemic cells.

Journal Article↗