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S Katsumata

Publications and source records attributed to S Katsumata.

32 records · Page 2Linked to original sources
PubMed1993

In situ hybridization study of interleukin-1 beta mRNA induced by kainic acid in the rat brain.

The distribution patterns of interleukin-1 beta (IL-1 beta) mRNA in various brain regions of saline- and kainic acid-treated rats were examined using in situ hybridization technique. In normal rat brain, the signals of IL-1 beta mRNA were observed in the cerebellar Purkinje cells and in dispersed cells in the hypothalamus. In the case of the kainic acid treatment, IL-1 beta mRNA was intensely induced in the olfactory bulb, lateral septum, thalamus, hypothalamus, polymorphic layers of hippocampus, piriform cortex, amygdala, entorhinal cortex and cerebral cortex at 2 h after the injection of kainic acid. In the hypothalamic region, we observed the induction of IL-1 beta mRNA around the paraventricular hypothalamic nucleus, anterior hypothalamic area, dorsomedial and ventromedial hypothalamic nucleus, mammillary regions and arcuate nucleus. The signal of IL-1 beta mRNA was still expressed 4 h after treatment with kainic acid, less intensely than at 2 h, but above the control level. In these regions, IL-1 beta mRNA was expressed mainly in the glial cells, which were densely stained by Cresyl violet and did not contain glial fibrillary acidic protein. These results suggest that IL-1 beta is produced by a certain type of glial cells, maybe microglia, and might have regulatory functions in the central nervous system.

Animals↗
PubMed1993

Sudden death due presumably to internal use of methamphetamine.

A 26-year-old male was found naked and excited in the backyard of his neighbor's house. He was carried to a nearby hospital, and returned home with his family, but took a sudden turn for the worse and died. In a judicial autopsy, the ethanol concentration of blood was found to be 0.58 milligrams, and methamphetamine (MA) was detected in his blood by thin-layer chromatography. The concentration of MA in his blood was 4.38 mumol/dl, higher than the fatal level. The amount of MA in his stomach was 5.8 mg (34.58 mumol/100 g), indicating that he ingested MA by internal use. Among the autopsy cases of acute MA poisoning reported in Japan, hyperesthesia is known to last 1-3 h before death, whether the administration is by intravenous injection or orally. But the present case is quite unusual, as the death followed 6 h or more of hyperesthesia. This was attributed to the patient's combined intake of alcohol with MA, as it is known to decrease the mortality in mice.

Adult↗
PubMed1992

Anticellular and antitumor activity of duocarmycins, novel antitumor antibiotics.

The anticellular and antitumor activities of novel antitumor antibiotics, duocarmycins (DUMs), were examined against human and murine tumor cells. DUMs consist of five compounds, A, B1, B2, C1 and C2, which possess a pharmacophore similar to that of CC-1065, a previously isolated antibiotic. Among them, DUMA exhibited ultrapotent growth-inhibitory activity with an IC50 value of 6 pM against human uterine cervix carcinoma HeLa S3 cells. DUMA and DUMB1 also inhibited the growth of adriamycin (ADM)-resistant lines of human nasopharynx carcinoma KB cells and breast carcinoma MCF-7 cells as well as their sensitive lines. DUMs inhibited the growth of s.c.-inoculated murine tumors such as B16 melanoma, sarcoma 180, M5076 sarcoma and colon 26. DUMs were also significantly effective in increasing the lifespan of i.p.-inoculated B16 melanoma-bearing mice, although their effect was marginal against other i.p.-inoculated tumors. As a whole, DUMB1 exhibited superior activity to the other four compounds. DUMB1 rapidly inhibited the incorporation of [3H]-TdR into macromolecules of HeLa S3 cells as compared with that of [3H]UR or [3H]leucine. DNA strand breaks were detected in DUMB1-treated HeLa S3 cells by agarose gel electrophoresis with a contour-clamped homogeneous electric field apparatus. These results indicate that DUMs possess interesting biological activities as DNA-targeting antitumor antibiotics.

Animals↗
PubMed1991

Duocarmycins, new antitumor antibiotics produced by Streptomyces; producing organisms and improved production.

Six duocarmycins have been discovered during our search for new antitumor antibiotics and they showed extremely potent cytotoxic activity with IC50 values of 10(-12) M-10(-9) M on HeLa S3 cell. Three different producing strains isolated from soils were taxonomically assigned as Streptomyces. Duocarmycin A was unstable in culture broth, so improved culture conditions were designed to produce a high titer of duocarmycins B1, B2, C1 and C2 which are halogenated seco-compounds of duocarmycin A. Duocarmycin SA, one of the most potent cytotoxic agents yet discovered, was shown to be more stable in culture media than duocarmycin A, despite the structural similarity on their spirocyclopropylhexadienone moiety. In contrast to the duocarmycin A fermentation, no halogenated seco-compounds of duocarmycin SA were detected in culture broth supplemented with Br- or Cl-. All duocarmycins could be produced using one producing strain with improved media and culture conditions.

Antibiotics, Antineoplastic↗
PubMed1989

Leinamycin, a new antitumor antibiotic from Streptomyces: producing organism, fermentation and isolation.

Leinamycin (DC 107) is newly discovered antitumor antibiotic with an unusual 1,3-dioxo-1,2-dithiolane structure. Five different producing strains were isolated from soils collected in Japan during 1985-1988 and were taxonomically assigned as Streptomyces. Fermentation studies indicate: Leinamycin was unstable in culture broth. A chemically defined medium could be designed for a preferable production. Streptomyces sp. S-140 grew on medium supplemented with Zn2+ and high porus polymer resin and accumulated 32 micrograms/ml of leinamycin. Improved isolation methods are described along with identification of mikamycin A co-produced with leinamycin by the strain S-140.

Antibiotics, Antineoplastic↗
PubMed1984

Ciliary and retinal changes in myotonic dystrophy.

We examined 15 patients with myotonic dystrophy by cycloscopy, ophthalmoscopy, and fluorescein angiography. In six cases, we found depigmentation in the relatively short ciliary processes, which may account for ocular hypotony in this disorder. Eight of the patients had retinal lesions, three with butterfly-shaped dystrophy, two with reticular dystrophy, and three with peripheral yellow flecks. These lesions were biomicroscopically at the level of the retinal pigment epithelium or in the deep retinal layer and did not substantially alter visual functions. Psychophysical and electrophysiologic test results were normal or only slightly affected. The butterfly-shaped and reticular dystrophies in myotonic dystrophy may be variant forms of patterned dystrophy of the retinal pigment epithelium. The peripheral yellow flecks in a stone-wall configuration noted in this disorder are particularly unique and, to our knowledge, have not been documented previously.

Adolescent↗
PubMed1984

Chorioretinitis sclopetaria caused by fishing line sinker.

A case of chorioretinitis sclopetaria caused by a grazing injury from a fishing line sinker was reported. A man was struck in his left orbit by the sinker, and immediately lost visual acuity. The sinker was removed, but funduscopy showed the typical appearance of chorioretinitis sclopetaria six months later. On fluorescein angiography, mottled background fluorescence appeared in a star-shaped scar. Fluorescein angiography, computed tomography, and roentgenography indicated that direct damage to the ciliary vessels was present.

Adult↗