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Biomedical subjects

Y Koyama

Publications and source records attributed to Y Koyama.

At least 19 recordsLinked to original sources
PubMed1992

Recombinant mouse tumor necrosis factor expressed in mammalian cells: effect of glycosylation on cytotoxic activity.

A mouse tumor necrosis factor-alpha (TNF) expression vector, pTNFNeo, was constructed by inserting a 1.3 kb cDNA coding for a full structural region of mouse TNF into an expression plasmid BCMGSNeo. COS7 cells were transfected with the pTNFNeo and a G418-resistant transfectant, BK-2, which stably secreted lytic activity to L929 cells was cloned. The lytic activity in the BK-2 culture spent medium reached up to 6000 U/ml, and was completely and specifically inhibited with antiserum to mouse TNF. Gel filtration chromatography and Western blot analysis indicated that the recombinant TNF in the medium existed in associated forms composed of a mixture of 22 kDa and 17.5 kDa components. Glycopeptidase F digestion indicated that the 22 kDa species was an N-glycosylated form of the 17.5 kDa species. Specific activities of the 22 kDa and the 17.5 kDa species isolated were 6.9 x 10(5) U/mg and 8.1 x 10(6) U/mg, respectively, suggesting that carbohydrate moiety impaired the lytic activity.

Animals↗
PubMed1992

Synthesis of 4'-deoxy-4'-fluorokanamycin A and B.

4'-Deoxy-4'-fluorokanamycins A (17) and B (25) have been prepared through fluorinative ring-opening of the D-galacto-3',4'-oxiranes (8 and 21) derived from kanamycin A and B with potassium hydrogenfluoride in ethane-1,2-diol. The mechanism of preponderant formation of the 4'-deoxy-4'-fluoro-D-gluco (9 and 22) over the 3'-deoxy-3'-fluoro-D-gulo derivatives was discussed. In the synthesis of 25, the unusual 3',6'-epimine (23) was the main product along with the 4'-deoxy-4'-fluoro derivative. The mechanism of this reaction is also discussed. Both 17 and 25 were active against resistant bacteria producing aminoglycoside-adenylylating enzymes for HO-4'.

Anti-Bacterial Agents↗
PubMed1992

Study on fluorination of 2,3-dideoxy-2,3-(N-tosylepimino)-alpha-D-allopyranosides, and synthesis of 3'-deoxy-3'-fluorokanamycin B and 3',4'-dideoxy-3'-fluorokanamycin B.

Reaction of the structurally rigid methyl 2,3-dideoxy-4,6-O-isopropylidene-2,3-(N-tosylepimino)-alpha-D-a llopyranoside (6) with KHF2 in DMF at 150 degrees gave initially methyl 2,3-dideoxy-2-fluoro-4,6-O-isopropylidene-3-tosylamido-alpha-D-altrop yranoside (10) by N-tosylepimine-ring opening, and 10 was gradually converted into the stable methyl 2,3-dideoxy-3-fluoro-4,6-O-isopropylidene-2-tosylamido-alpha-D-glucopyra noside (11). A reversible mechanism involving 6 and 10 has been proposed. In the mobile methyl 2,3-dideoxy-2,3-(N-tosylepimino)-alpha-D-allopyranoside (7) and the corresponding 4,6-di-O-acetyl (8) and -di-O-methyl derivatives (9), reactions with KHF2 proceeded comparatively rapidly giving the corresponding 3-deoxy-3-fluoro-alpha-D-glucopyranosides as the major products. A slightly different reaction mechanism for the mobile compounds has been proposed. By application of this study, 3'-deoxy-3'-fluorokanamycin B was prepared by treatment of 4",6"-O-cyclohexylidene-2'-deamino-3'-deoxy-3'-epi-6'-N-methoxycarbonyl- 1,3, 3"-tri-N-tosyl-2',3'-(N-tosylepimino)kanamycin B (21) with KHF2 as the key reaction. 3',4'-Dideoxy-3'-fluorokanamycin B was also prepared. Both compounds were active against resistant bacteria producing 3'-modifying enzymes.

Carbohydrate Sequence↗
PubMed1992

Mapping of prostaglandin E2 binding sites in rat brain using quantitative autoradiography.

The density of specific prostaglandin E2 (PGE2) binding sites was quantitatively mapped in the rat brain using in vitro autoradiography. The anterior wall of the third ventricle and the nucleus solitary tract were found to have a very high density of binding sites (greater than 15 fmol/mg tissue). Two thalamic nuclei (paraventricular and anteroventral nuclei) and the dorsal parabrachial nucleus contained a high density of binding sites (10-15 fmol/mg tissue). Entorhinal cortex, ventral hippocampus, amygdala, dorsomedial hypothalamus, mammillary complex, some thalamic nuclei, central gray, superior colliculus, raphe nuclei, locus coeruleus, spinal trigeminal nucleus (caudal part) and the dorsal horn of the spinal cord (laminae 1 and 2) had each a moderate density of binding sites (5-10 fmol/mg tissue). Binding tended to occur in brain regions rich in neuronal cell bodies or neuronal cell processes (dendrites and axon terminals). PGE1, whose central actions are very similar to those of PGE2, had essentially the same pattern of binding sites as did PGE2 throughout the entire brain, suggesting there are receptors common to these two PGEs. In addition to already known functions of receptors common to these two PGEs. In addition to already known functions of PGE2 in the hypothalamus, which include fever genesis, promotion of wakefulness, cardiovascular control and LH-RH release, the unique distribution of extrahypothalamic PGE2 binding sites found in this study suggests its involvement in the processing or modulation of viscerosensory, somatosensory (nociceptive and possibly thermal) and visual inputs as well as in the central integration of autonomic and limbic functions.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1992

Fine structure of nerve processes containing basic fibroblast growth factor in muscle spindles of the rat masseter muscle.

An antiserum against basic fibroblast growth factor (bFGF) was characterized by immunoblot analysis and used to investigate the fine structure of bFGF-containing processes in muscle spindles of the rat masseter muscle. The bFGF antiserum recognized purified bFGF and bFGF-like materials with the same molecular weight as bFGF in crude homogenate of the brainstem from which bFGF fibers in the masseter muscle spindles presumably originate. Immunoelectron micrographs demonstrated that both proprioceptive and motor nerve endings in contact with intrafusal fibers contain bFGF. These findings suggest that bFGF of central (possibly trigeminal mesencephalic and motor nucleus) origin is transported into the muscle spindles subserving mechanoreception.

Animals↗
PubMed1992

Specific distribution of an epididymal 50 kDa protein revealed by an anti-Mos protein monoclonal antibody.

An anti-Mos protein monoclonal antibody, 4A6, was used to investigate the distribution of the antigen in the epididymis, in which the c-mos gene is reportedly expressed. The 4A6-reactive antigen was found on the basement membrane and luminal surface of the epithelial cells in the caput epididymis of BALB/c male mice as well as in the proximal corpus epididymis, the cauda epididymis, and the vas deferens. The 4A6 antigen was also found on the luminal surface of the epithelial cells in the epididymis of male germ cell-deficient C57BL/6J-Wv/Wv mice. This confirmed that the 4A6 antigen does not derive entirely from the testicular c-Mos protein but is synthesized in the epididymis. Western blot analysis revealed that the molecular weight of the epididymal 4A6 antigen was 50 kDa, which is unusually high for the c-Mos protein. With its specific distribution in the epididymis, the protein should play a specific role in functions of the epididymis.

Animals↗
PubMed1992

Basic fibroblast growth factor-like immunoreactivity in Purkinje cells of the rat cerebellum.

An antiserum against basic fibroblast growth factor was characterized by immunoblot experiments and used to investigate immunohistochemically the projection fields and fine structures of basic fibroblast growth factor-containing cerebellar Purkinje cells. The antiserum demonstrated clearly purified basic fibroblast growth factor and basic fibroblast growth factor-like molecules of the same molecular weight in homogenates of the adult rat cerebellum. Light and electron microscopic immunohistochemistry revealed that a large number of Purkinje cells, if not all, send immunoreactive dendrites to the molecular layer and basic fibroblast growth factor-containing axons to the deep cerebellar and lateral vestibular nuclei, where basic fibroblast growth factor nerve terminals form synapses with the soma and dendrites of neurons labeled weakly with basic fibroblast growth factor. Nerve cells with basic fibroblast growth factor had immunoreaction deposits mainly in free ribosomes, those attached to the endoplasmic reticulum and in the nuclear euchromatin. These findings suggest that basic fibroblast growth factor is present in cerebellar Purkinje cells and undergoes two modes of transport, one to axon terminals and the other to nuclear euchromatin, known as the RNA transcription zone.

Animals↗
PubMed1992

Localized, aggregative, and diffuse adherence to HeLa cells, plastic, and human small intestines by Escherichia coli isolated from patients with diarrhea.

Adherence of diarrhea-associated Escherichia coli was studied by scanning electron microscopy. Enteropathogenic E. coli (EPEC) adherence factor-positive (EAF+) E. coli of EPEC serotypes (class I EPEC) adhered to plastic and human jejunal and ileal mucosa, similar to case and HeLa cells. Localized adherence, elongation of cell microvilli, and "locking" of the bacterial aggregates by the elongated microvilli were evident after incubation for 20 min. EAF+ E. coli adhered strikingly to mucus but rarely to M cells in Peyer's patch-associated epithelium. Most enteroaggregative E. coli (EAggEC) strains adhered to plastic, similar to HeLa cells. Some diffuse-adhering E. coli (DAEC) strains displayed no adherence to plastic but formed "dimples" on HeLa cells. Both EAggEC and DAEC adhered at lower levels to human small intestines (except M cells) than did EAF+ E. coli. In all cases of EAF+ E. coli, EAggEC, and DAEC, strains were found with atypical characteristics. The data demonstrate the unique adherence characteristics of EAF+ E. coli, EAggEC, and DAEC.

Adhesins, Escherichia coli↗
PubMed1992

[Utility of Mahalanobis distance in evaluating the results of health examination].

A method using Mahalanobis distance (D2), the general probability distance in multivariate analysis, was studied for evaluating the results of health examination. D2 of each subject was computed by a personal computer with a BASIC program, and those whose D2 values lay out of 95% confidence interval were considered to be abnormal. In the present study, the mean value and standard deviation come from a normal range of Japanese, and the correlation coefficients between two items were obtained from blood donors in the hospital. These three parameters were necessary for calculation of D2. To examine the availability of this method, the data of a health examination on 370 new employees from 18 to 25 yr in age were analyzed with 9 items, including systolic pressure (SBP), diastolic pressure (DBP), serum glutamic oxaloacetic transaminase activity (GOT), serum glutamic pyruvic transaminase activity (GPT), serum gamma glutamyl transpeptidase activity (GGTP), serum total cholesterol (TCHO), serum triglyceride (TG), number of erythrocytes (RBC), and concentration of hemoglobin (Hb). It was shown that the data distributions of GOT, GPT, GGTP, and TG were log normal, and those of the other items were normal. With this method, 39 persons were also judged as abnormal from 46 subjects diagnosed to be abnormal by doctors, and the remaining 7 were missed but could be classed to be normal, as six of them had only slightly high levels of GPT (33-39 IU/l) and/or GGTP (42-57 IU/l), and one had a slightly high SBP (146 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Mammalian toxicity of empenthrin (Vaporthrin, S-2852F)].

1. Acute toxicity: Empenthrin ((RS)-(EZ)-1-ethynyl-2-methyl-2-pentenyl (1R)-cis/trans-chrysanthemate) caused some toxic signs such as muscular fibrillation, tremor, hypersensitivity, decrease of spontaneous activity, ataxic gait, lymb paralysis, irregular respiration, excretion of oily substance, loose stool and urinary incontinence in oral acute toxicity studies at 1000 mg/kg and above in rats, and at 2000 mg/kg and above in mice. The oral LD50 value was estimated greater than 5000 mg/kg (male) and greater than 3500 mg/kg (female) in rats and greater than 3500 mg/kg (both sexes) in mice. In both rats and mice, the toxic signs were not found at 2000 mg/kg by dermal administration. The dermal LD50 value was estimated greater than 2000 mg/kg (both sexes) in both rats and mice. The LC50 value in rats for the acute inhalation toxicity of empenthrin was estimated to be greater than 4610 mg/m3 for both sexes. The LC50 value in mice was determined to be 2700 mg/m3 for male and 2300 mg/m3 for female. Mice showed higher sensitivity to empenthrin than rats. 2. Reproductive and developmental toxicity: Empenthrin was orally administered to fetal organogenesis periods of rats at the dose levels of 50, 150 and 500 mg/kg, and of rabbits at 100, 300 and 1000mg/kg. Maternal toxicity was found at 500 mg/kg in rats and at 300 mg/kg or more in rabbits. There were no teratogenicity, no embryotoxicity and no fetal retardation in rats or rabbits. In addition, there were no adverse effects on F1 pups growth, development or reproductive performance. 3. Subchronic toxicity: Empenthrin was orally administered to male and female SD rats at dose levels of 0 (corn oil), 10, 100 and 300 mg/kg for 26 weeks. Clinical signs, body weight, food and water consumption were monitered, and hematological, blood biochemical, ophthalmological and histopathological examination were carried out. As a result, changes related to administration of empenthrin were observed mainly in the liver and kidneys in rats receiving 100 mg/kg or more. Therefore, the no-effect-level of empenthrin is determined to be 10 mg/kg in both sexes of rats in this study.

Administration, Oral↗
PubMed1992

Synthesis and activity of 3-(isoxazolin-5-yl)- and 3-(isoxazol-4-yl)cephalosporins.

The 1,3-dipolar cycloaddition of nitrile oxide with 3-vinylcephalosporin provided diastereomeric isomers of 3-(isoxazolin-5-yl)cephalosporin. Cycloaddition of nitrile oxide with 3-(dimethylamino-vinyl)cephalosporin gave 3-(isoxazol-4-yl)cephalosporin. These semisynthetic cephalosporins with an aminothiazole in the C-7 side chain showed moderate antibacterial activities.

Anti-Bacterial Agents↗
PubMed1992

Synthesis and activity of potent 3-(isoxazolidin-5-yl)- and 3-(isoxazolidinium-5-yl)cephalosporins.

The syntheses and in vitro antibacterial activities of 3-(isoxazolidin-5-yl)- and 3-(isoxazolidinium-5-yl)cephalosporins are described. 1,3-Dipolar cycloaddition of 3-vinylcephalosporin with nitrone gave diastereomeric isomers of 3-(isoxazolidin-5-yl)cephalosporin. The antibacterial activities of 3'-(S)-isomers were superior to those of 3'-(R)-isomers. The quaternarization of isoxazolidine ring increased the antibacterial activity. Among them, compound 10b with a hydroxyimino group in the C-7 side chain showed potent activities against staphylococci and compound 10f with an N-hydroxypyridone exhibited an excellent antipseudomonal activity.

Anti-Bacterial Agents↗
PubMed1992

In vitro receptor autoradiography: a map for exploring the hypothalamus.

In rabbits and guinea pigs, hypothalamic sites for prostaglandin E2 (PGE2) action were studied by means of in vitro receptor autoradiography. The density of PGE2 binding sites (probably PGE2 receptors) was the highest in the anterior wall of the third ventricle (A3V). This result is consistent in all mammalian species ever studied, suggesting a fundamental role of the A3V in the hypothalamic action of PGE2, such as fever.

Animals↗
PubMed1992

[Flow cytometric techniques for measurement of proliferating cell nuclear antigen (PCNA)].

Flow cytometric techniques have been developed for measurement of proliferating cell nuclear antigen (PCNA), which allows studies on the proliferative capacity of cells and tissues. PCNA-DNA dual staining procedures, for both fixed and unfixed cells, and analytical method by FCM are presented. We recommend performing either the fixed or unfixed method. Our studies using the MCF7 human breast adenocarcinoma cell line and the A549 human lung squamous cell carcinoma cell line, in the exponential growth phase, revealed that both ethanol and acetone were satisfactory fixatives, in contrast to methanol and paraformaldehyde, and PI with a concentration of 25 micrograms/ml was most suitable compared with 50 and 100 micrograms/ml.

Adenocarcinoma↗
PubMed1992

[Neo-adjuvant chemotherapy with tegafur suppository for rectal cancer--evaluation of the antitumor effects, tissue levels of 5-FU and inhibition of thymidylate synthase. Tochigi Colorectal Cancer Study Group].

We evaluated antitumor effect histologically and assayed the tissue levels of 5-fluorouracil (5-FU) and thymidylate synthase (TS) activity using surgical specimens obtained from the patients with rectal cancer, who were given tegafur suppositories prior to surgery. The antitumor effect was evaluated histologically according to classification of the general rules for the gastric cancer study (Japanese Research Society for Gastric Cancer). In 39 patients, 16 tumor specimens revealed no effect (grade-0), 22 tumors grade-1 effect, and one was not evaluable because of the severe inflammatory changes. In 23 of these patients, resected specimens were available for the assay. 5-FU levels in cancer tissues were significantly higher than those in normal tissues, and TS inhibition rates (TSIR) were almost identical, averaging around 20%, in both cancer and normal tissues. Comparing the 5-FU levels and TS activity according to the histological effects (i.e.: 'grade-0' vs 'grade-1'), the 5-FU levels in the tumors achieved grade-1 were significantly higher than in the tumors showed 'grade 0' (p less than 0.01), and TSIR in the former were relatively greater than in the latter (p = 0.053). It is suggested that both tissue levels of 5-FU and TSIR may be useful parameters to predict the anti-tumor effect against rectal cancer after administration of 5-FU and its derivatives.

Chemotherapy, Adjuvant↗