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Biomedical subjects

A Iida

Publications and source records attributed to A Iida.

At least 73 records · Page 4Linked to original sources
PubMed1998

Micro X-ray diffraction analysis of thin films using grazing-exit conditions.

An X-ray diffraction technique using a hard X-ray microbeam for thin-film analysis has been developed. To optimize the spatial resolution and the surface sensitivity, the X-ray microbeam strikes the sample surface at a large glancing angle while the diffracted X-ray signal is detected with a small (grazing) exit angle. Kirkpatrick-Baez optics developed at the Photon Factory were used, in combination with a multilayer monochromator, for focusing X-rays. The focused beam size was about 10 x 10 micro m. X-ray diffraction patterns of Pd, Pt and their layered structure were measured. Using a small exit angle, the signal-to-background ratio was improved due to a shallow escape depth. Under the grazing-exit condition, the refraction effect of diffracted X-rays was observed, indicating the possibility of surface sensitivity.

Journal Article↗
PubMed1998

Structure of the mouse klotho gene and its two transcripts encoding membrane and secreted protein.

We previously established a novel mouse model for human aging and identified the genetic foundation responsible for it. A defect in expression of a novel gene, termed klotho (kl), leads to a syndrome resembling human aging in mice. The kl gene encodes a single-pass membrane protein whose extracellular domain carries homology to beta-glucosidases. In this report, we present the entire mouse kl gene organization. The mouse kl gene spans about 50 kilobases and consists of five exons. The promoter region lacks a TATA-box and contains four potential binding sites for SP1. We further show that two kl gene transcripts encoding membrane or secreted protein are generated through alternative transcriptional termination. These findings provide fundamental information for further study of the kl gene which may regulate aging in vivo.

Alternative Splicing↗
PubMed1998

Site-specific lead distribution in scales of lead-administered carp (Cyprinus carpio) by non-destructive SR-XRF analysis.

By utilizing non-destructive synchrotron radiation-excited X-ray fluorescence (SR-XRF), we observed the distribution of lead (Pb) in both ontogenic and regenerating scales of lead-administrated carp, Cyprinus carpio. The fish in the Pb-administered group were fed pellets containing 1 mg/g of Pb at a rate of 1.5% body weight per day for 30 days. In the ontogenic scales, Pb was highly accumulated near the basal edge of the scale and the accumulated amount decreased toward the focus of the scale. On the other hand, in the regenerating scales, high accumulation was observed near the basal edge and the accumulated amount remained high toward the focus. The present results of Pb accumulation correspond well with the region which is calcifying in the ontogenic and regenerating scales, and indicate that the distributions of Pb show when and how long Pb was administered.

Animals↗
PubMed1998

Antitumor-promoting naphthoquinones from Catalpa ovata.

Bioassay-directed fractionation of an extract of the stem-bark of Catalpa ovata led to the isolation of three new naphthoquinones: 8-methoxydehydroiso-alpha-lapachone (1), 9-methoxy-4-oxo-alpha-lapachone (2), and (4S,4aR,10R,10aR)-4, 10-dihydroxy-2,2-dimethyl-2,3,4,4alpha,10, 10alpha-hexahydrobenzo[g]chromen-5-one (3), which is a 1,4-reductive form of 6. The known compounds 3-hydroxydehydroiso-alpha-lapachone (4), 4,9-dihydroxy-alpha-lapachone (5), 4-hydroxy-alpha-lapachone (6), and 9-methoxy-alpha-lapachone (7), and catalpalactone (8) were also isolated. Their structures were elucidated by spectral methods. These compounds all exhibited significant inhibitory activity against 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced Epstein-Barr virus early antigen (EBV-EA) activation in Raji cells.

Antigens, Viral↗
PubMed1998

Extent of myocardial damage in regions with reverse redistribution at 3 h and at 24 h on 201Tl SPET: evaluation based on regional myocardial oxidative metabolism.

Reverse redistribution (RRD) of 201Tl is often observed in patients with recent myocardial infarction. However, the difference in the extent of myocardial damage between regions with 3-h RRD and those with 24-h RRD remains unknown. Accordingly, we investigated RRD from the standpoint of myocardial oxidative metabolism. Carbon-11 (11C) acetate dynamic myocardial PET scanning was performed at rest in 14 patients with recent myocardial infarction, and the clearance rate constant (Kmono) of 11C-acetate was calculated in 6-7 ROIs on the transaxial image in each patient using a monoexponential fit as an index of myocardial oxidative metabolism. Exercise 201Tl myocardial SPET was also performed. Ninety-two regions corresponding to the PET study were then classified based on the findings of transaxial 201Tl SPET imaging; that is, regions with reverse redistribution, regions with severely decreased 201Tl activity or no 201Tl activity on the 24-h delayed images, and regions with normal 201Tl activity throughout the study. Kmono in regions with reverse redistribution (0.051 +/- 0.009 min-1) was significantly lower than that in regions with normal 201Tl activity throughout the study (0.066 +/- 0.011 min-1) (P < 0.001) but significantly higher than that in regions with severely decreased or no 201Tl activity on the 24-h delayed images (0.037 +/- 0.003 min-1) (P < 0.001). Percent Kmono (i.e. Kmono in region with RRD/the mean of Kmono in all regions with a normal 201Tl SPET result) was significantly lower in the 3-h RRD regions (81.3 +/- 6.3%) than in the 24-h RRD regions (87.6 +/- 6.1%) (P < 0.05). Impairment of myocardial oxidative metabolism is observed in regions with RRD, suggesting that RRD corresponds to mild myocardial damage. Reverse redistribution on 24-h delayed images may indicate much milder myocardial damage compared with RRD on 3-h delayed images.

Acetates↗
PubMed1998

Allelic loss on chromosome 9q is associated with lymph node metastasis of primary breast cancer.

Frequent allelic losses on chromosome 9 are seen in a wide variety of human tumors; moreover, two genes (P16 and PTC) whose mutant alleles confer predispositions to some inherited cancer syndromes have been identified on this chromosome. Using 15 highly polymorphic microsatellite markers distributed on both arms of chromosome 9, we tested 96 primary breast carcinomas for allelic loss in order to define the locations of genes that might be involved in this type of tumor. Allelic loss was observed in 37 of the tumors (39%) and detailed deletion mapping identified target regions at 9p21, 9q22.3 and 9q33. Losses at 9q22.3 and 9q33 were correlated with the presence of lymph node metastasis, and allelic loss at 9q22.3 was observed more frequently in scirrhous tumors than in less aggressive histologic types. Therefore, inactivation of tumor suppressor genes in 9q22.3 and 9q33 regions might play a role in progression of breast cancers, especially in metastasis to lymph nodes and in development of scirrhous tumors.

Adenocarcinoma, Scirrhous↗
PubMed1998

Frequent allelic loss at 7p14-15 associated with aggressive histologic types of breast cancer.

We examined 142 primary human breast cancers to determine their patterns of loss of heterozygosity (LOH) at 19 microsatellite markers over the entire length of chromosome 7. Allelic loss at one or more loci on the short arm of chromosome 7 was observed in 37 of the tumors (26%). We found a new target region of allelic loss on 7p between D7S1802 and D7S817 at 7p14-15. LOH on 7p was found more frequently in tumors of the invasive solid tubular and scirrhous type (31 of 87); 36%) than in other less aggressive types (2 of 27; 7%) (P = 0.0047). The results suggest that inactivation of putative tumor suppressor gene(s) located at 7p14-15 may play a role in the development and/or progression of primary breast cancers, particularly those of the invasive solid tubular and scirrhous type. Allelic loss was also found in 56 of 142 tumors on the long arm, and a commonly deleted region was defined between D7S522 and D7S1801 at 7q31.

Breast Neoplasms↗
PubMed1998

[Predictability of Gleason score and reduction time (tau) of prostatic volume after castration for the prognosis of prostatic cancer].

PURPOSE: The efficacy of the reduction time (tau) after castration as a prognostic factor was examined by comparing to Gleason score. MATERIALS AND METHODS: The change of prostatic volume after castration was observed from the castration to 3 months after in 24 cases of prostatic cancer. Prostatic volume was examined by transrectal ultrasonography of the prostate. Survival curves was calculated by Kaplan-Meier method. Differences among survival curves were analyzed using Cox-Mantel test. RESULTS: tau had a close relationship to the prognosis of each case (Wilcoxon test: p < 0.05, Cox-Mantel test: p < 0.05). Gleason score had a weak relationship to prognosis (Wilcoxon test: N. S., Cox-Mantel test: p < 0.05). CONCLUSIONS: tau was efficient as prognostic factor compared to Gleason score.

Aged↗
PubMed1998

Mapping of a new target region of allelic loss to a 2-cM interval at 22q13.1 in primary breast cancer.

Allelic losses on chromosome arm 22q are frequently observed in human meningiomas and in carcinomas of the colon, ovary, and breast. Among 140 primary breast cancers we examined for loss of heterozygosity (LOH) at 16 polymorphic loci on the long arm of chromosome 22, 56 (40%) showed LOH for at least one locus. Eleven of these tumors had retained heterozygosity for markers proximal to the NF2 locus but showed LOH for markers distal to NF2. Deletion mapping indicated a new common region of deletion, 2-cM in extent, at q13.1 between Interleukin 2 receptor beta (IL2RB) and D22S279. Our results raise the possibility that one or more tumor suppressor genes associated with breast cancer may exist at 22q13.1. Comparison of these results with clinicohistological data indicated that allelic losses on 22q tend to occur more frequently in tumors of malignant histological types.

Alleles↗
PubMed1998

[Effect of attenuation by the cranium on quantitative SPECT measurements of cerebral blood flow and a correction method].

Attenuation correction for cerebral blood flow SPECT image reconstruction is usually performed by considering the head as a whole to be equivalent to water, and the effects of differences in attenuation between subjects produced by the cranium have not been taken into account. We determined the differences in attenuation between subjects and assessed a method of correcting quantitative cerebral blood flow values. Attenuations by head on the right and left sides were measured before intravenous injection of 123I-IMP, and water-converted diameters of both sides (Ta) were calculated from the measurements obtained. After acquiring SPECT images, attenuation correction was conducted according to the method of Sorenson, and images were reconstructed. The diameters of the right and left sides in the same position as the Ta (Tt) were calculated from the contours determined by threshold values. Using Ts given by 2Ts = Ta - Tt, the correction factor gamma = exp (mu(1)Ts) was calculated and multiplied as the correction factor when rCBF was determined. The results revealed significant differences between Tt and Ta. Although no gender differences were observed in Tt, they were seen in both Ta and Ts. Thus, interindividual differences in attenuation by the cranium were found to have an influence that cannot be ignored. Inter-subject correlation is needed to obtain accurate quantitative values.

Aged↗
PubMed1998

[Telomerase activity in colorectal carcinoma and its relationship to clinicopathological findings].

Telomerase is thought to be responsible for cell immortality. The telomerase activity in carcinomas has been remarked since 1995. We examined telomerase activity in colorectal carcinoma by TRAP (Telomeric repeat amplification protocol) assay, and investigated its relationship to clinicopathological findings. We could analyse telomerase activities in 33 cases (66%) of 50 colorectal carcinomas, whereas the activity was not found in all 13 cases of noncancerous colorectal mucosa. There was no relation between the telomerase activity and the clinicopathological findings or metastatic status. We confirmed telomerase activities in much of colorectal carcinomas in spite of their progression. The carcinoma cells might be immortal from their early stage of progression by means of telomerase activity.

Colorectal Neoplasms↗
PubMed1998

Mapping of a new target region of allelic loss to a 6-cM interval at 21q21 in primary breast cancers.

A detailed analysis of loss of heterozygosity (LOH) in breast cancers was performed with 11 microsatellite markers on the long arm of chromosome 21. Among the 142 tumors examined, 44 (31%) showed LOH at one or more loci. Peak LOH frequency was observed on band 21q21. Deletion mapping identified a new commonly deleted region in a 6-cM interval of 21q21 between loci D21S1432 and D21S1437, and raised the possibility that one or more tumor suppressor genes associated with breast cancer may exist in this region. Comparison of these alterations with clinicopathological parameters revealed an association of LOH on 21q with loss of progesterone receptor (P = 0.0013).

Breast Neoplasms↗
PubMed1998

[A case of stage IV (N4) esophageal cancer successfully treated with concurrent chemoradiotherapy].

A 71-year-old man with inoperable intrathoracic esophageal cancer was treated by concurrent chemoradiation. A dose of 48 Gy (neck) and 60.6 Gy (mediastinum) and four courses of 5-FU (500 mg/day)-CDDP (50 mg/week) were delivered. The esophageal tumor and metastatic lymph nodes of the neck showed a complete response (CR) to the treatment, whereas paraaortic lymph nodes evidenced no change (NC). The patient is doing well without symptoms at 13 months after treatment. The chemoradiotherapy produced effective improvement and quality of life in this patient.

Aged↗
PubMed1997

Correlation of Allelic Losses and Clinicopathological Factors in Primary Breast Cancers.

Human breast cancers frequently show allelic loss or loss of heterozygosity (LOH) at apecific chromosomal regions. To understand the possible role of these genetic alterations in tumor development and progression, we examined LOH at loci on chromosomal arms 1p, 3p. 11p, 13q, 16q, 18q, and 22q in 140 to 246 cases of primary breast cancers and compared it with lymph node metastasis, histological type, tumor stage, estrogen receptor (ER) and progesterone receptor (PgR) status. LOH at 1p22-31 correlated with lymph node metastasis and a tumor size of greater than 2 cm. LOH at 13q12-14 and 18q21 were most frequently observed in tumors of the solid-tubular type. LOH at 1p34-36 was more frequent in tumors of the scirrhous and solid-tubular types than in other less aggressive histological types. Furthermore, a significant association was observed between LOH at 3p14-21, 11p11-15 and 13q12-14 and the absence of progesterone receptors. These results suggest that some clinical characteristics of breast cancers are determined by loss of tumor supperssor genes present at specific chromosomal regions.

Journal Article↗
PubMed1997

Mutation of the mouse klotho gene leads to a syndrome resembling ageing.

A new gene, termed klotho, has been identified that is involved in the suppression of several ageing phenotypes. A defect in klotho gene expression in the mouse results in a syndrome that resembles human ageing, including a short lifespan, infertility, arteriosclerosis, skin atrophy, osteoporosis and emphysema. The gene encodes a membrane protein that shares sequence similarity with the beta-glucosidase enzymes. The klotho gene product may function as part of a signalling pathway that regulates ageing in vivo and morbidity in age-related diseases.

Aging↗
PubMed1997

Role of the Gln/Glu residues of trichocellins A-II/B-II in ion-channel formation in lipid membranes and catecholamine secretion from chromaffin cells.

Trichocellins (TC) A-II and B-II, 20-residue peptaibols isolated from conidia of the fungus Trichoderma viride, have the same sequence except for the residue at position 18. Both TCs were found to form voltage-dependent ion-channels in bilayer lipid membranes (BLM) and to induce catecholamine secretion from bovine adrenal chromaffin cells through Ca2+ influx. TC-A-II (Gln18, neutral) was more effective than TC-B-II (Glu18, charged) for macroscopic current induction in BLMs and for catecholamine secretion from chromaffin cells, suggesting that Glu18 is unfavorable for the ion-channel formation in BLMs and chromaffin cell membranes. Nevertheless, single-channel recordings indicated that TC-B-II forms larger pores with longer open lifetimes than those of TC-A-II. This indicates that the negatively charged carboxyl group of Glu at position 18 stabilizes larger pores. The effects of the negative charge of Glu18 on the activities were confirmed by the use of a TC-B-II analog containing the methyl ester of Glu18.

Animals↗