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Biomedical subjects

M Yoshikawa

Publications and source records attributed to M Yoshikawa.

At least 19 recordsLinked to original sources
PubMed1995

Survival of neurons containing the enzyme nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase in static slice cultures of adult rat striatum.

The present study concerns the survival potential of mature neurons containing the enzyme nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase in the static slice culture of adult rat striatum. In the striatal tissues immediately after slicing, there was a scattered distribution of NADPH-diaphorase neurons stained in a Golgi-like manner, and the cell density of those neurons was 53 +/- 5 (mean +/- SEM; n = 10) cells per mm2. The time-sequential cell density analysis disclosed that the number of striatal NADPH-diaphorase neurons surviving after 1, 2, 4 and 6 day in culture were 26 +/- 5, 8 +/- 2, 5 +/- 2, and 3 +/- 2 (means +/- SEM; n = 10) cells per mm2, respectively. Thus, approximately 50% of striatal NADPH-diaphorase neurons survived for 1 day and a significant proportion of these neurons, although their number gradually decreased, were maintained in culture for at least several days. The conspicuous survival of the striatal NADPH-diaphorase neurons in slice culture is thought to reflect the damage-resistant natures of these cells.

Animals↗
PubMed1995

Effect of gluten exorphins A5 and B5 on the postprandial plasma insulin level in conscious rats.

The effect of exogenous opioid peptides, gluten exorphins A5 and B5, which were isolated from the enzymatic digest of wheat gluten, on the postprandial insulin level were examined in rats. The oral administration of gluten exorphin A5 at a dose of 30 mg/kg w. potentiated the postprandial plasma insulin level and the effect was reversed by naloxone. The administration of gluten exorphin B5 showed a similar effect at a higher dose (300 mg/kg w). Furthermore, intravenous administration of gluten exorphin A5 at a dose of 30 mg/kg w. also stimulated the postprandial insulin release. The fact that orally and intravenously administered gluten exorphin A5 stimulates insulin release suggests that it modulates pancreatic endocrine function by the action after the absorption rather than within the the gastrointestinal tract.

Administration, Oral↗
PubMed1995

Isolation and characterization of ovokinin, a bradykinin B1 agonist peptide derived from ovalbumin.

A vasorelaxing peptide was purified from a peptic digest of ovalbumin, after three steps of reverse-phase HPLC. The structure of the peptide was Phe-Arg-Ala-Asp-His-Pro-Phe-Leu, which corresponded to residues 358-365 of ovalbumin. The peptide was named ovokinin. Ovokinin showed relaxing activity for a canine mesenteric artery (EC50 = 6.3 microM). The relaxing activity was blocked by the bradykinin B1 antagonist [des-Arg9] [Leu8]bradykinin, but not by the B2 antagonist Hoe 140. Ovokinin binds to B1 receptors (IC50 = 64 microM). Prostaglandin I2 was released from the artery after ovokinin stimulation as a relaxing factor. Thus, ovokinin is a weak bradykinin B1 agonist peptide derived from food proteins.

1-Methyl-3-isobutylxanthine↗
PubMed1995

Characteristics of choledochal cysts in neonates and early infants.

Thirty-six infants with choledochal cyst consisting of 28 babies less than 12 months of age and 8 between 13 and 24 months of age, were analyzed. Characteristics of cases were as follows: (1) they were usually of the cystic type, (2) a huge abdominal mass and jaundice with alcoholic stool were typically found, (3) no symptom suggesting acute pancreatitis was observed, (4) amylase levels in bile were usually low, despite the presence of pancreatobiliary malunion, while other pancreatic enzymes in bile commonly showed a high concentration, and (5) primary cyst excision and biliary reconstruction was the treatment of choice, and could be safely performed with favorable outcomes even in babies less than 1 year of age.

Amylases↗
PubMed1995

Identification of a novel virulence gene, virA, on the large plasmid of Shigella, involved in invasion and intercellular spreading.

A novel virulence gene (virA) was identified upstream of the virG gene on the large plasmid of Shigella flexneri 2a YSH6000. Characterization of virA mutants infecting MK2 epithelial cell monolayers revealed that their invasive capacity was decreased to less than one fifth of the wild-type level. Nevertheless, the bacteria were capable of expressing and secreting IpaB, IpaC and IpaD proteins. The virA mutants were also impaired in their ability to spread intercellularly, since the bacteria gave rise to a small number of foci in a focus-plaque-forming test with MK2 cells. Although virG expression was slightly decreased in the virA mutants, introduction of a cloned virG gene into a virA mutant, N1945, failed to restore spreading ability. Although, introduction of a cloned virA gene into N1945 restored invasiveness and spreading ability, the reduced virG transcription level was not affected, indicating that the reduced virG expression in virA mutants does not play a major role in defective intercellular spreading. The nucleotide sequence of the virA region revealed that the virA gene was located 528 bp upstream of the virG gene, in the opposite orientation. The deduced amino acid sequence of the VirA protein indicated a 44.7 kDa protein with no homology to known proteins. The VirA protein was secreted into the culture supernatant, a process that required the Mxi and Spa loci. The expression of virA was under the control of the virB gene, the positive regulator of the ipa, mxi and spa operons. These results indicate that virA is a new member of the invasion regulon directed by virB and that the VirA function is involved in invasion and intercellular spreading.

Amino Acid Sequence↗
PubMed1995

Therapeutic effect of percutaneous ethanol injection on small hepatocellular carcinoma: evaluation with CT.

PURPOSE: To evaluate the therapeutic effect of percutaneous ethanol injection (PEI) on small hepatocellular carcinoma (HCC) with computed tomography (CT). MATERIALS AND METHODS: Sixty-seven patients with histologically proved HCC 3 cm or less in diameter underwent PEI. The patients were regularly followed up with sonography and contrast material-enhanced CT for more than 1 year (range, 12-96 months). The CT findings were evaluated for three tumor types distinguished on the basis of their appearance relative to that of the surrounding liver parenchyma: type 1 = hyperattenuating at the early phase (n = 39), type 2 = iso- or hypoattenuating at the early phase and hypoattenuating at the late phase (n = 18), and type 3 = isoattenuating (not detected) at both the early and late phases (n = 10). RESULTS: After PEI, a necrotic area of HCC and the surrounding liver parenchyma was characterized as hypoattenuating at both early and late phases of contrast-enhanced CT, regardless of the type. When an HCC appeared to be completely necrotic within 3 months after PEI, this status was retained until the latest observation in all but three cases. CONCLUSION: Contrast-enhanced CT can correctly depict PEI-induced necrosis in HCC and is reliable for evaluating the therapeutic effect of PEI.

Carcinoma, Hepatocellular↗
PubMed1995

Rhodiocyanosides A and B, new antiallergic cyanoglycosides from Chinese natural medicine "si lie hong jing tian", the underground part of Rhodiola quadrifida (Pall.) Fisch. et Mey.

Two new antiallergic cyanoglycosides named rhodiocyanosides A and B were isolated from the Chinese natural medicine "Si Lie Hong Jing Tian" (Shiretsukoukeiten in Japanese), the underground part of Rhodiola quadrifida (Pall.) Fisch. et Mey., together with two new glycosides, octyl alpha-L-arabinopyranosyl(1-6)-beta-D-glucopyranoside and gossypetin 7-O-beta-D-glucopyranosyl(1-3)-alpha-L-rhamnopyranoside. Their chemical structures were determined on the basis of chemical and physicochemical evidence. Rhodiocyanosides A and B exhibited inhibitory activity on the histamine release from rat peritoneal exudate cells sensitized with anti-DNP IgE. In addition, rhodiocyanoside A was found to inhibit the PCA reaction in rats.

Animals↗
PubMed1995

Chemical constituents of Chinese natural medicine, morindae radix, the dried roots of morinda officinalis how.: structures of morindolide and morofficinaloside.

A new iridoid lactone, morindolide, and a new iridoid glucoside, morofficinaloside, have been isolated from a Chinese natural medicine, Morindae Radix, the dried root of Morinda officinalis How. together with a number of known compounds: five anthraquinones, four iridoid glucosides, a monoterpene glycoside, two sterols, an ursane-type triterpene, and a lactone compound. The chemical structures of the new compounds were determined on the basis of chemical and physicochemical evidence.

Acetylation↗
PubMed1995

Absolute stereostructures of hovenidulciosides A1 and A2, bioactive novel triterpene glycosides from hoveniae semen seu fructus, the seeds and fruit of Hovenia dulcis Thunb.

Two bioactive novel triterpene glycosides named hovenidulciosides A1 and A2 have been isolated from a Chinese natural medicine, Hoveniae Semen Seu Fructus, the seeds and fruit of Hovenia dulcis Thunb. (Rhamnaceae). The absolute stereostructures of hovenidulciosides A1 and A2 with a migrated 16,17-seco-dammarane skeleton have been determined on the basis of chemical and physicochemical evidence which included the X-ray crystallographic analysis of the p-bromobenzoate of their common aglycone, hovenidulcigenin A. Hovenidulciosides A1 and A2 exhibited inhibitory activity on the histamine release from rat mast cells induced by compound 48/80 or calcium ionophore A-23187.

Animals↗
PubMed1995

[Effects of thunberginol A contained in Hydrangeae dulcis forium on types I-IV allergies].

The inhibitory actions of thunberginol A on anti-allergic (type I-IV) activity were examined. Oral administration of thunberginol A 2 hr before the challenge significantly inhibited the PCA reaction (type I) in rats at a dose of more than 300 mg/kg and the ear PCA reaction in mice at a dose of more than 50 mg/kg. Thunberginol A at a dose of more than 300 mg/kg also significantly inhibited the allergic bronchoconstriction in rats. Thunberginol A concentration-dependently (10(7)-10(-4), 10(-5)-10(-4) M) inhibited the allergic contractions of rat trachea sensitized with IgE and those of the guinea pig lung preparation sensitized with IgG. It also inhibited the allergic histamine release from sensitized peritoneal exudate cells in a concentration-dependent manner (10(-5)-10(-4) M). Thunberginol A had anti-serotonic activity on the contraction of smooth muscle, and it increased the ear vascular permeability in mice. Thunberginol A significantly inhibited the primary response of contact dermatitis (type IV) in mice at 100 mg/kg from the day after immunization to the day before challenge, and it also inhibited the delayed type foot pad swelling in mice at a dose of more than 300 mg/kg at 0 and 8 hr after the challenge. These findings suggest that orally administered thunberginol A is effective against type I and type IV allergy.

Administration, Oral↗
PubMed1995

Characteristics of prolactin secretion in normal and estrogen-treated pituitaries of rats at the single cell level: analysis by reverse hemolytic plaque assay.

We studied PRL release from individual pituitary cells in normal and estrogen (E2)-treated female Fischer 344 rats by means of a reverse hemolytic plaque assay. In this assay, the area of the hemolytic plaque around a pituitary cell is proportional to the amount of hormone secreted from the cell. Multimodal distribution of the plaque area was observed in normal pituitary cells, and was unchanged in the course of aging. In E2-treated pituitary cells, bimodal distribution was found. The heterogeneity of the distribution pattern (functional heterogeneity) and PRL secretion from a single pituitary cell decreased in association with the length of E2 treatment. The mean plaque area for the E2-treated pituitary cells was smaller than that for the normal pituitary cells. These results suggest that in E2-treated pituitary cells, the functional heterogeneity and PRL release from a single cell decrease as tumorigenesis progresses.

Animals↗
PubMed1995

Bystander effect caused by suicide gene expression indicates the feasibility of gene therapy for hepatocellular carcinoma.

In the field of gene therapy using retroviral vectors, it appears impossible to introduce a foreign gene into all target cells. Therefore adjacent cell killing, the socalled bystander effect, caused by genetically modified cells provides therapeutic advantages for gene therapy against cancers. We retrovirally transduced the herpes simplex virus thymidine kinase (HSV-tk) gene into murine and rat hepatocellular carcinoma (HCC) cells. These HSV-tk gene-transduced HCC cells were cocultured with the corresponding parental cells in the presence of ganciclovir, at a concentration not at all cytotoxic to the parental cells. When parental HCC cells were cocultured with their HSV-tk gene-transduced counterparts at a high density at which most cells were in contact with one another, they were markedly eliminated. Conversely, when cocultured at a low density at which none of the cells were in contact, a weak but statistically significant bystander effect was observed. Addition of lysates of HSV-tk gene-transduced cells in the presence of ganciclovir did not cause and killing of parental cells. Furthermore, media conditioned by transduced cells with ganciclovir exhibited weak cytotoxic effects on parental cells. These results indicate that cell-cell contact plays a major causative role in the bystander effect and that minor contributors to this phenomenon are some cytotoxic substance released from transduced cells. Importantly, the bystander effect was induced in vivo as well as in vitro. When mixtures of transduced and untransduced HCC cells were implanted into the flank region of mice, intraperitoneal ganciclovir administration considerably inhibited tumor development, indicating the feasibility of gene therapy with HSV-tk gene and ganciclovir against HCC.

Animals↗
PubMed1995

[Studies on production of interleukin-1 beta (IL-1 beta) and granulocyte. Macrophage-colony stimulating factor (GM-CSF) by peripheral blood monocytes from patients with Mycobacterium avium-intracellulare complex (MAC) infection].

Production of Interleukin-1 beta (IL-1 beta) and granulocyte macrophage-colony stimulating factor (GM-CSF) by peripheral blood monocytes (PBMs) from patients with Mycobacterium avium-intracellulare complex (MAC) infection was assessed and the relationship with their clinical course was analyzed. PBMs were obtained from MAC-infected patients in their active stage as well as in the inactive stage and the healthy controls. Spontaneous release of IL-1 beta by PBMs from patients in the active stage was higher than those by the cells in the inactive stage or the healthy controls. On the other hand, spontaneous GM-CSF release by PBMs from patients in the active stage was higher than the healthy controls. When PBMs were stimulated with MAC-derived purified protein derivatives (PPD-B), increased production of both IL-1 beta and GM-CSF were obtained for PBMs in their active stage. While these enhanced production upon stimulation with PPD-B related to the persistent infection with MAC, the increased IL-1 beta production correlated with the exhausted nutritional state. Both IL-1 beta and GM-CSF produced by PBMs seemed to be closely related with the clinical course of human MAC infection.

Aged↗
PubMed1995

[The evaluation of interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) level in peripheral blood of patients with active pulmonary tuberculosis].

We investigated the serum level of IL-8 and TNF-alpha using ELISA in 16 patients with active pulmonary tuberculosis before administration of antituberculous drugs and in age-, smoking habit-matched 20 healthy controls. The mean level of serum IL-8 in patients with active pulmonary tuberculosis was significantly higher than that in healthy controls (P < 0.001). The mean level of serum TNF-alpha in tuberculosis patients was also high, while TNF-alpha was not detectable in the sera of healthy controls. We also examined the relationship between clinical pictures mainly defined by radiographic findings and the serum levels of IL-8 and TNF-alpha. The serum IL-8 level of 9 patients with tuberculous cavity is significantly higher than that of 7 patients without cavity. (P < 0.05) We classified the patients with cavities into two subgroups according to the radiographic classification of the Japanese Society of Tuberculosis. Four patients with advanced lesions on chest X-ray showed higher serum IL-8 level than 5 patients with moderate lesions (P < 0.05). On the other hand, there was no correlation between serum TNF-alpha level and radiographic findings. These results suggest that IL-8 appears to be involved in the formation of tuberculous cavitary lesion.

Adult↗
PubMed1994

Absolute stereostructures of hydramacrosides A and B, new bioactive secoiridoid glucoside complexes from the leaves of Hydrangea macrophylla Seringe var. thunbergii Makino.

Two new bioactive secoiridoid glucoside complexes named hydramacrosides A and B were isolated from the leaves of Hydrangea macrophylla SERINGE var. thunbergii MAKINO. The absolute stereostructures of hydramacrosides A and B were elucidated on the basis of chemical and physicochemical evidence which included the application of the 13C NMR glycosylation shift rule of 1, 1'-disaccharides and the modified Mosher's method. Hydramacrosides A and B exhibited inhibitory effect on the histamine release from rat mast cells induced by antigen-antibody reaction.

Animals↗
PubMed1994

Development of bioactive functions in hydrangeae dulcis folium. III. On the antiallergic and antimicrobial principles of hydrangeae dulcis folium. (1). Thunberginols A, B, and F.

From the less polar fraction of Hydrangeae Dulcis Folium, the fermented and dried leaves of Hydrangea macrophylla Seringe var. thunbergii Makino, Eight antiallergic and antimicrobial principles were isolated together with several known compounds. Among the newly isolated bioactive constituents, the chemical structures of thunberginols A, B, and F have been determined on the basis of chemical and physicochemical evidence. Thunberginols A, B, and F were found to exhibit more potent antiallergic activity than phyllodulcin, hydrangenol, disodium cromoglycate (DSCG), and tranilast. In addition, these thunberginols showed antimicrobial activity against oral bacteria.

Animals↗
PubMed1994

[Development of bioactive functions in hydrangeae dulcis folium. II. Antiulcer, antiallergy, and cholagoic effects of the extract from hydrangeae dulcis folium].

In order to develop new bioactive functions of Hydrangeae Dulcis Folium, the fermented and dried leaves of Hydrangea macrophylla Seringe var. thunbergii Makino, effects of the methanolic extract from the crude drug on antiucler, antiallergic, cholagoic, and various pharmacological actions were investigated. Consequently, the methanolic extract was found to exhibit potent antiulcer, antiallergic, and cholagoic activities. By monitoring with these activities, it was found that the active constituents were contained in the lipophilic portion of the methanolic extract. Furthermore, the known lipophilic constituents such as phyllodulcin and hydrangenol were found to show little antiulcer and cholagoic activities, while it was also found that they showed antiallergic activity on Schultz-Dale reactions.

Animals↗