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Biomedical subjects

H Tabata

Publications and source records attributed to H Tabata.

At least 37 records · Page 2Linked to original sources
PubMed1998

Ferromagnetism in LaFeO3-LaCrO3 superlattices

Ferromagnetic spin order has been realized in the LaCrO3-LaFeO3 superlattices. Ferromagnetic coupling between Fe3+ and Cr3+ through oxygen has long been expected on the basis of Anderson, Goodenough, and Kanamori rules. Despite many studies of Fe-O-Cr-based compounds, random positioning of Fe3+ and Cr3+ ions has frustrated the observation of ferromagnetic properties. By creating artificial superlattices of Fe3+ and Cr3+ layer along the [111] direction, ferromagnetic ordering has been achieved.

Journal Article↗
PubMed1998

Characterization of self-glutamic acid decarboxylase 65-reactive CD4+ T-cell clones established from Japanese patients with insulin-dependent diabetes mellitus.

To investigate autoimmunity to glutamic acid decarboxylase (GAD) 65 in Japanese patients with insulin-dependent diabetes mellitus (IDDM, type I diabetes), we established seven CD4+ T-cell clones, by stimulating peripheral blood mononuclear cells (PBMC) of six IDDM patients, using a mixture of overlapping human GAD65 peptides. No GAD65 autoreactive T-cell clones were evidenced in four healthy controls. Specificities of T-cell clones were as follows: (a) two clones specific to GAD65 p111-131 (residue 111 to 131) + DR53 (DRB4*0103); (b) one clone specific to GAD65 p413-433 + DR1 (DRB1*0101); (c) two clones specific to GAD65 p200-217 + either DR9 (DRB1*0901) or DR8 (DRB1*0802); and (d) two clones specific to GAD65 p368-388 + DP2 (DPA1*01 or 0201-DPB1*0201). Two DR53-restricted and one DR1-restricted T-cell clones, responded to a recombinant human GAD65 protein, and showed cytotoxicity against B lymphoblastoid cell lines pre-pulsed with the peptides. Six T-cell clones exhibited the Th1-like phenotype. Interestingly, two DR53-restricted T-cell clones killed a Fas-deficient B lymphoblastoid cell line, thereby indicating that cytotoxicity was not completely dependent on a Fas-Fas ligand interaction. Thus, the T-cell epitopes were mapped in a limited portion of GAD65 protein, with a tendency to be restricted by disease-associated HLA-DR, but not DQ molecules.

Adolescent↗
PubMed1998

Tissue interaction regulates expression of a spasmolytic polypeptide gene in chicken stomach epithelium.

The primitive epithelium of embryonic chicken proventriculus (glandular stomach) differentiates, after day 6 of incubation, into luminal epithelium, which faces the lumen and abundantly secretes mucus, and glandular epithelium, which invaginates into mesenchyme and later expresses embryonic chicken pepsinogen (ECPg). So far it is not well understood how undifferentiated epithelial cells differentiate into these two distinct cell populations. Spasmolytic polypeptide (SP) is known to be expressed in surface mucous cells of mammalian stomach. In order to obtain the differentiation marker for proventricular luminal epithelial cells, we cloned a cDNA encoding chicken SP (cSP). Sequence analysis indicated that cSP has the duplicated cysteine-rich domain characteristic of SP. Examination of the spatial and temporal expression pattern of cSP gene revealed that, during embryogenesis, cSP was expressed in lumina epithelial cells of the proventriculus, gizzard, small intestine, and lung, but not the esophagus. In the proventriculus, cSP mRNA was first detected on day 8 of incubation and was localized to differentiated luminal epithelial cells. By using cSP as a molecular marker, the effects of mesenchyme on the differentiation of epithelium were analyzed in vitro. On the basis of these data, a model is presented concerning the differentiation of proventricular epithelium.

Amino Acid Sequence↗
PubMed1998

Comparison of effects of restraint, cage transportation, anaesthesia and repeated bleeding on plasma glucose levels between mice and rats.

We examined the effects of handling, cage transportation, anaesthesia and repeated bleeding on plasma glucose levels in mice and rats. Plasma glucose was determined using a compact glucose analyser Antsense, which provides a quick and accurate method without the necessity for special specimen preparation. In mice, plasma glucose was significantly elevated after primary handling or cage transportation. Anaesthesia increased plasma glucose levels two-fold, whilst repeated bleeding induced a rapid but transient increase. However, it was found to be possible to sample plasma glucose levels at one-hour intervals without any apparent effect on plasma glucose level as a result of stress from the sampling procedure. In contrast, the same set of procedures i.e. handling, cage transportation and anaesthesia, when performed on rats, seemed to have small or no observable effect on levels of plasma glucose. These results show the importance of the sampling procedure when determining plasma glucose in mice. It is recommended that the procedure which causes the least influence on endogenous glucose levels should be the method of choice and that animals should be acclimatized to the procedure, by appropriate handling, prior to sampling.

Anesthesia↗
PubMed1998

Bandlike melasma mimicking linear morphea ("en coup de sabre" type).

A case of bandlike melasma on the median line of the forehead of a middle-aged woman is described. It was an atypical case for its clinical shape and distribution. At initial examination, it was diagnosed as linear morphea. Epidermal nevus was another differential diagnosis. Based on the presence of minor protuberance and the absence of atrophy, clinically, and the presence of sebaceous glands and the absence of swelling of collagen fibers, documented histologically, we revised our diagnosis to that of an atypical type of melasma.

Adult↗
PubMed1997

Arterial gene transfer of acidic fibroblast growth factor for therapeutic angiogenesis in vivo: critical role of secretion signal in use of naked DNA.

OBJECTIVE: Previous studies have demonstrated that arterial gene transfer of naked DNA encoding for a secreted protein may permit modulation of the host phenotype despite a low transfection efficiency. Acidic fibroblast growth factor (aFGF) is an angiogenic growth factor, but is not secreted by intact cells. In the current study, we investigated the hypothesis that addition of a hydrophobic leader sequence to achieve active secretion of the gene product would permit therapeutic angiogenesis following arterial gene transfer of naked DNA encoding for aFGF. METHODS: Ten days following surgical induction of unilateral hindlimb ischemia, New Zealand white rabbits were randomized to intra-arterial gene transfer with one of three plasmids: p267 (encoding non-secreted aFGF, n = 10), pMJ35 (encoding secreted aFGF) (n = 10), or 500 micrograms of pGSVLacZ (control, n = 10) (500 micrograms each). All animals were studied at 30 days post-gene transfer for evidence of therapeutic angiogenesis. RESULTS: pMJ35 transfectants had more angiographically visible collaterals (angiographic score = 0.76 +/- 0.02) than either p267 (0.55 +/- 0.02, p < 0.01) or LacZ (0.47 +/- 0.02, p < 0.001). Limb blood pressure ratio for pMJ35 was 0.88 +/- 0.02 vs. 0.68 +/- 0.04 for p267 (p < 0.01) and 0.57 +/- 0.04 for LacZ (p < 0.001). Vascular resistance was significantly lower in the pMJ35 group, compared with that in pGSVLacZ group, both in resting state (3.2 +/- 0.4 vs. 7.4 +/- 1.4 respectively, p < 0.05) and after the administration of nitroprusside. Capillary density (per mm2) was also superior in pMJ35 group (274 +/- 10) vs. p267 (204 +/- 9, p < 0.01) and LacZ (177 +/- 6, p < 0.001). CONCLUSION: The paracrine effects of a secreted gene product may obviate the need for adjunctive vectors in strategies of arterial gene therapy.

Analysis of Variance↗
PubMed1997

Cutaneous localization of endothelin-1 in patients with systemic sclerosis: immunoelectron microscopic study.

BACKGROUND: Endothelin-1 (ET-1) has some relation to the pathogenesis of systemic sclerosis (SSc) and Raynaud's phenomenon. This study was performed to determine the localization of ET-1 in patients with SSc. METHODS: The localization of ET-1 on the specimen by skin biopsies from nine patients with SSc, was observed with immunoelectron microscopic techniques. RESULTS: High-density deposits existed on the ribosomes and on the rough endoplasmic reticulum in the endothelial cells of microvessels of the upper dermis. The same findings were also seen in the fibroblasts of the dermis, but not found in the skin of normal controls. The level of deposits in the endothelial cells and dermal fibroblasts seemed to have a positive correlation with the serum levels of ET-1 of patients with SSc. CONCLUSIONS: From these results, it can be seen that ET-1 is produced much more from the endothelial cells and fibroblasts of the dermis in the skin of SSc patients than from the normal controls. It is suspected that ET-1 is one of the pathogenetic factors of SSc.

Biopsy↗
PubMed1997

[A case of colon cancer with local recurrence successfully treated by systemic and local intra-arterial chemotherapy using a combination of 5-fluorouracil, interferon-alpha 2A, leucovorin and carboplatin].

A 59-year-old man with colon cancer was diagnosed as having a local recurrence of the disease, forming a huge intra pelvic tumor, accompanied by pulmonary metastasis 16 months after hemicolectomy. He received alternate systemic and local chemotherapy consisting respectively of a 5-day course of continuous infusion of 5-FU 600 mg/m2/day, bolus injection of leucovorin (LV) 20 mg/m2/day, intramuscular injection of interferon (IFN)-alpha 2a 6 x 10(6) IU/day, and intra-arterial administration of 5-FU, LV and carboplatin using reservoir catheter through pudendal artery, each repeated every 3 weeks. After 6 systemic and 8 local treatments, metastatic lesions disappeared and the intra-pelvic tumor shrunk by 62%, indicating a partial response. The patient then underwent dissection of the intra-pelvic tumor. Pathological examination indicated a curative resection. Alternate systemic and local intra arterial chemotherapy using a combination of 5-FU, LV, IFN and and carboplatin is highly promising for metastatic colorectal cancer with local recurrence.

Adenocarcinoma↗
PubMed1996

Methyl jasmonate-induced overproduction of paclitaxel and baccatin III in Taxus cell suspension cultures.

Taxus cell culture may be an alternative source of paclitaxel and related taxane production. Significantly increased amounts of paclitaxel and baccatin III were observed in cultured cells of Taxus species after exposure to methyl jasmonate. Among the three species of Taxus tested, Taxus media showed the highest paclitaxel content while Taxus baccata showed the highest baccatin III content when 100 microM of methyl jasmonate was added to the culture media. Furthermore, the activities of methyl jasmonate and related substances for inducing paclitaxel production were compared in cell suspension cultures of T. media. Methyl jasmonate and its free acid showed the strongest promoting activity. Reduction of the keto group at the C-3 position greatly reduced this activity. cis-Jasmone, which does not have a carboxyl group at the C-1 position, had almost no activity. These results suggest that these two regions of methyl jasmonate are important for promoting the production of paclitaxel and related taxanes in Taxus cell cultures.

Acetates↗
PubMed1996

Electron-microscopic study of sclerodermatous chronic graft-versus-host disease.

BACKGROUND: Sclerodermatous chronic graft-versus-host disease (SC-GVHD) resembles systemic scleroderma (SSD) closely, both clinically and histologically. Our purpose was to try to define the morphologic differences of collagen fibers between SC-GVHD and SSD. MATERIALS AND METHODS: Using electron microscopy, we compared the morphology of collagen fibers in a 15-year old girl with SC-GVHD with those of three patients with SSD. RESULTS: In SC-GVHD, sclerosis is located in the superficial dermis and collagen fibers of irregular diameter are seen in the subepidermal area. In SSD, sclerosis is seen in the lower dermis and subcutaneous fatty tissue, and collagen fibers of irregular diameter are located in the deep dermis. Some of the collagen fibers were degenerative in the superficial dermis in SC-GVHD. We observed low-density, round structures in cross sections of collagen fibers. CONCLUSIONS: The difference in initial location and morphologic appearance of collagen fibers may indicate a different pathogenesis in SC-GVHD compared to SSD.

Adolescent↗
PubMed1996

Oncogenicity studies of the new serotonin (5-HT)3-receptor antagonist ramosetron in mice and rats.

Oncogenicity studies of ramosetron ((R)-5-[(1-methyl-3-indolyl)carbonyl]-4,5,6,7-tetrahydro-1H-benzimidazol e hydrochloride, CAS 132907-72-3, YM060), a new compound having serotonin (5-HT)3 receptor antagonist activity, were carried out in male and female mice and rats. Six groups (two control and four treated) of B6C3F1 mice and F344 rats were given YM060, dissolved in distilled water, once daily by oral intubation at doses of 0, 1, 10, 30 and 100 mg/kg/d. Toxicokinetics indicated that sufficient exposure of the animals to the test material was achieved during the oncogenicity studies. Cmax and AUC of YM060 at 100 mg/kg/d were in the range of 3-5 micrograms/ml and 8 micrograms.h/ml in mice, 1-5 micrograms/ml and 7-16 micrograms.h/ml in rats, respectively. The administration of YM060 resulted in a slightly increased mortality rate among female rats treated with 30 or 100 mg/kg/d, particularly during the Weeks 38-87. Body weights of the high-dosed male and female rats during the Weeks 36 to 96 were significantly decreased when compared to controls. An approximately 30% suppression of body weight gain was recorded during Weeks 36-96 for both male and female rats, and 15% suppression of body weight gain was recorded during Weeks 0-104 for male mice. There was no evidence of a treatment-related effect on the incidence of any tumor or tumor type, and there were no non-neoplastic findings considered to be related to the administration of YM060. All microscopic changes seen in mice and rats were of the usual type commonly occurring in untreated aged B6C3F1 mice and F344 rats. In conclusion, there was no evidence of an oncogenic effect of YM060 in mice and rats.

Animals↗