Search PubMed⌕ Search

Biomedical subjects

H Kusakabe

Publications and source records attributed to H Kusakabe.

At least 37 records · Page 2Linked to original sources
PubMed1995

Extracellular glutamate: on-line monitoring using microdialysis coupled to enzyme-amperometric analysis.

An enzyme-amperometric detector cell is described for flow analysis of glutamate in dialysate emerging from an implanted microdialysis probe. Its small size allows it to be placed within a few centimetres of the animal preparation, reducing the delay for data acquisition to around 2 min. The selectivity is provided by glutamate oxidase, immobilised with glutaraldehyde on surfaces adjacent to the 3-electrode system. A film of 1,2-diaminobenzene, electropolymerized on the platinum working electrode, eliminates interference from ascorbic acid and other endogenous electroactive compounds. The high sensitivity (< 0.5 mumol/l) and fast response time of the cell (90% of maximum response in 30 s) make it particularly suitable for investigating conditions that produce rapid changes in brain extracellular glutamate. This is illustrated by monitoring changes in extracellular glutamate subsequent to cardiac arrest, and K(+)-induced local depolarization.

Amino Acid Oxidoreductases↗
PubMed1994

Metastatic epithelioid sarcoma with an N-ras oncogene mutation.

At age 25 a Japanese woman noticed an elastic-hard nodule 2 cm in diameter on the anterior side of her right leg. The nodule had developed an ulcer in its center. Simple resection was performed several times. However, the lesion recurred repeatedly. The patient underwent amputation of the right leg at the age of 34, because the diagnosis of epithelioid sarcoma was established histologically. No recurrence was observed for 9 years. Recently, the patient noticed multiple painful, ulcerative nodules about 1 cm in diameter on her scalp, trunk, and extremities. She refused extensive resection for a religious reason and died of massive hematemesis. Autopsy revealed metastatic epithelioid sarcoma in the skin, lungs, kidneys, pancreas, transverse colon, thyroid, and sternum. Chromosomal analysis of the tumor revealed various aberrations and an N-ras oncogene mutation.

Adult↗
PubMed1992

A non-radioisotopic reverse transcriptase assay using biotin-11-deoxyuridinetriphosphate on primer-immobilized microtiter plates.

We developed a non-radioisotopic (non-RI) reverse transcriptase assay (RTA). The reverse transcriptase (RT) incorporates biotin-11-deoxyuridine-triphosphate (bio-dUTP) using a poly(rA) template hybridized with oligo(dT) primer that is immobilized on the surface of a 96-well microtiter plate. This assay is thus semi-automated by adapting it to an ELISA testing format. The incorporation of bio-dUTP was enhanced by adding cold dTTP to the reaction mixture, optimally in a molar ratio 4:1 (dTTP:bio-dUTP). This non-RI RTA is more sensitive than the conventional RI assay for the detection of purified Rous-associated virus 2 (RAV-2) and of human immunodeficiency virus type 1 (HIV-1) lysate. Because of its simple procedure, higher sensitivity and non-use of RI materials, the assay can be utilized not only for virological studies but also for routine safety screening of biological products for retroviral contamination.

Avian Leukosis Virus↗
PubMed1992

A statistical study on clinical findings of solar keratosis.

Clinical findings were studied in 50 patients with 53 lesions of solar keratosis encountered during the 15 year period from 1977 to 1991. The majority of these cases were evident in the over-sixty age group (average 62.2 years). A greater proportion were females. Most lesions were observed on the face; especially on the cheek, and from the outer eyelid to the temple. The erythematous type (desquamative-keratotic) lesion was the most evident. With the exceptions of the years 1979 and 1991, no remarkable increase in the number of patients was noted during the 15 year period.

Adult↗
PubMed1992

A statistical study on histopathologic findings of solar keratosis.

We examined histopathologic data from 50 patients with 53 lesions of solar keratosis encountered over the past 15 years (1977 to 1991). The epidermis showed acanthosis, uneven epidermal dyeing properties, disorderly arrangement of the basal cells, atypia of the nucleus, mitotic figures and hyperpigmentation of the basal layers. The dermis showed actinic elastosis, cell infiltration mainly consisting of the lymphoid cells, and incontinentia pigmenti histologica. Among histologic types, the hypertrophic type was the primary example.

Adult↗
PubMed1991

Isolation and characterization of phosmidosine. A new antifungal nucleotide antibiotic.

A new nucleotide antibiotic, phosmidosine was isolated from a culture filtrate of a newly isolated streptomycete identified as Streptomyces sp. RK-16. HRFAB-MS and elemental analysis established the molecular formula of C16H24N7O8P. 1H, 13C and 31P NMR indicated the presence of a methyl phosphate group and UV spectra were similar to those of 8-hydroxyadenosine. The antibiotic inhibited spore formation of Botrytis cinerea at the concentration of 0.25 micrograms/ml.

Antifungal Agents↗
PubMed1990

A new inhibitor of protein kinase C, RK-286C (4'-demethylamino-4'-hydroxystaurosporine). I. Screening, taxonomy, fermentation and biological activity.

In the course of our screening program using a bleb-forming assay, a new inhibitor of protein kinase C (PKC) was found in the fermentation of a streptomycete. The inhibitor, RK-286C (4'-demethylamino-4'-hydroxystaurosporine), inhibited the morphological change of K562 cells, a human chronic erythroleukemia cell, induced by phorbol 12,13-dibutylate at the concentration of 3 microM. The same concentration of the compound inhibited the activity of PKC in vitro and the aggregation of rabbit platelets induced by collagen and arachidonic acid.

Alkaloids↗
PubMed1989

Epiderstatin, a new inhibitor of the mitogenic activity induced by epidermal growth factor. I. Taxonomy, fermentation, isolation and characterization.

Inhibitors of mitogenic activity induced by epidermal growth factor (EGF) were screened from culture broths of soil microorganisms. A strain of actinomycetes has been found to produce a new glutarimide antibiotic named epiderstatin which inhibits the incorporation of [3H]thymidine into quiescent animal cells stimulated by EGF. Taxonomic studies have revealed that the producing strain belongs to a subspecies of Streptomyces pulveraceus, thus the name, Streptomyces pulveraceus subsp. epiderstagenes was given to this strain. The molecular formula (C15H20N2O4) and UV profile (lambda max 295 nm) of the antibiotic are distinct from other known antibiotics. It inhibited the incorporation of [3H]thymidine into quiescent cells stronger than into growing cells.

Animals↗
PubMed1988

A new antifungal antibiotic, cystargin: fermentation, isolation, and characterization.

A new sulfur-containing peptide antifungal antibiotic, cystargin, was isolated from the fermentation broth of a new species of genus Kitasatosporia, designated as Kitasatosporia cystarginea. On acid hydrolysis, cystargin (C60H77N19O17S6) gave equimolar glycine, proline, aspartic acid and arginine. By performic acid oxidation, cysteic acid was detected after hydrolysis. It showed a growth inhibitory activity against various phytopathogenic fungi and inhibition of beta-1,3-glucan synthetase from Saccharomyces cerevisiae.

Actinomycetales↗
PubMed1987

Mutagenic reactivities of 3,4-dinitrobiphenyl derivatives.

3,4-Dinitrobiphenyl derivatives were mutagenic in Salmonella typhimurium TA98, TA98/1,8-DNP6 and in TA98NR. We describe here the specific reactivity of 3,4-dinitrobiphenyl derivatives with diluted sodium hydroxide solution and the determination of the amounts of released nitrous ion. 3,4-Dinitrobiphenyl derivatives begin to release nitrous ions when treated with NaOH solution at a concentration of 10(-3) N. The behavior of 4NQO and o-dinitrobenzene was the same as that of 3,4-dinitrobiphenyl derivatives. The residues of 3,4-dinitrobiphenyl derivatives, after releasing nitrous ions, were estimated to be hydroxy-nitrobiphenyls, as by GC/MS, we found the formation of o-nitrophenol in the reaction mixture of o-dinitrobenzene with aqueous NaOH solution. 3,4,4'-Trinitrobiphenyl, 3,4,3',4'-tetranitrobiphenyl and 4NQO had reduced mutagenic potency in Salmonella typhimurium TA98 following treatment with diluted NaOH. In order to elucidate the ultimate forms of 3,4-dinitrobiphenyl derivatives, we investigated the reaction of o-dinitrobenzene as a basic model substance of 3,4-dinitrobiphenyl, with nucleic bases in the presence of NaOH in nonaqueous solvent. o-Nitrophenyl guanine and adenine adducts were obtained.

Dinitrobenzenes↗
PubMed1986

Relationship between mutagenic potency in Salmonella typhimurium strains and the chemical structure of nitro biphenyls.

Most of the positional isomers of mono-, di-, tri- and tetranitrobiphenyls were synthesized and assayed for their mutagenicity in Salmonella typhimurium strains TA98, TA98NR and TA98/1,8DNP6 in the absence of S9 mix. In mono- and dinitrobiphenyls, the structure requirements favoring mutagenic activity are the presence of a nitro group at the 4-position and its absence at the 2-position. TA98 and TA98/1,8DNP6 were reverted by 2-position-free 4-nitro analogues, but TA98NR was not reverted. The results suggest that direct-acting mutagenicity involves the reduction of the nitro group by bacterial nitroreductase but does not involve specific esterification enzymes. Some of the tri- and tetranitrobiphenyls e.g. 3,4,3'-, 3,4,4'-, 3,4,3',4'- and 3,4,2',4'-derivatives reverted not only TA98 and TA98/1,8DNP6 but also TA98NR. Those derivatives commonly have 2 nitro groups at an adjoining position (3,4-dinitro group), whereas 2,4,2',4'-tetranitrobiphenyl, which has strong potency not only in TA98 and TA98/1,8DNP6 but also in TA98NR, possesses 2 nitro groups at the 2-position of each benzene ring.

Biphenyl Compounds↗