Kenzo Yamagata

Localization of terminal deoxynucleotidyl transferase (TdT) in rat thymus using immunoperoxidase methods

SummaryIndirect and peroxidase anti-peroxidase (PAP) immunoenzymatic methods were used to detect terminal deoxynucleotidyl transferase (TdT) in imprints and formalin-fixed paraffin sections of normal rat thymus. TdT is found in the nuclei of small lymphocytes in imprint samples from neonatal and adult rat thymus, showing granular or circular patterns of peroxidase reaction products. Diffuse brown reaction products of peroxidase are located in both the nuclei and cytoplasm of medium and large lymphocytes. Indirect measurements show that, as age progresses, the percentage of peroxidase-positive cells decreases in all types of lymphocytes, from 72.4% on the 11th day to 54.8% in the 5th month, whereas that of negative cells increases from 14.4% to 39.4%. In formalin-fixed paraffin sections, peroxidase-positive lymphocytes are found mainly in the cortex and cortico-medullary boundary, and only rarely in the medulla.

Dose-modifying effect of a cyanidine chloride derivative, keracyanin, for uv irradiation of murine L fibroblasts cultured in vitro.

The protection potential against uv light (254-nm wavelength) of keracyanin, one of the flavonoids, was examined in cultured murine fibroblasts, L cells. Pretreatment of L cells with 4.5 x 10/sup -4/ M keracyanin for 20 min provided protection against the lethal action of uv light. Ultraviolet dose--survival curves for the exponentially growing cells showed that the dose reduction factor (D/sub 0/ for the treated cells/D/sub 0/ for the untreated ones) was about 1.4. The protection selectively appeared in uv-sensitive S phase cells, while the survival of less uv-sensitive cells at the G/sub 1/-S border and in G/sub 2/ was apparently not affected by the drug.

Quick gas chromatographic method for measuring the water content of brain tissue: with reference to age-related changes of rat neocortex.

A quick and accurate method for estimating tissue water content by gas chromatography was developed. Age-related changes in tissue water content in the neocortex of rat brain were easily determined by this method.