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Biomedical subjects

H Iwase

Publications and source records attributed to H Iwase.

At least 127 records · Page 7Linked to original sources
PubMed1998

Microstructure and homogeneity of dental porcelain frits.

The microstructure and homogeneity of three commercial dentin and incisal unfired porcelain frits (one conventional and two ultra-low fusing types, fused-to metal were analyzed by X-ray diffractometry, scanning electron microspectroscopy, and wavelength- and energy dispersive X-ray microspectroscopy. The average contents of tetragonal and cubic leucite for the conventional and one of the ultra-low fusing type frits were 20.1-22.6 wt% and 0-2.6 wt%, respectively, whereas those of another of the ultra-low fusing type frits were about 11.5-11.6 wt% and 2.9-4.6 wt%, respectively. The conventional type frits seemed to be admixtures of three kinds of glass frits. One of the ultra-low fusing type frits seemed to be an admixture of four kinds of glass frits. Another ultra-low fusing frits seemed to be only one kind of glass frit dispersed with small size, less than 1 micron, leucite crystals. There were no remarkable differences in microstructure and homogeneity between dentin and incisal porcelain frits in each brand.

Aluminum Silicates↗
PubMed1998

[Immunohistochemical staining of thymidine phosphorylase in primary colorectal carcinoma and metastases].

Thymidine phosphorylase (TdRPase) is an enzyme involved in the pyrimidine metabolism. It was reported that many cancers contained higher levels of TdRPase than normal tissues. And TdRPase has been reported to be identical with the platelet-derived endothelial cell growth factor. To clarify the distribution of TdRPase in primary and metastatic colorectal cancer, we carried out immunohistochemical staining of formalin-fixed specimens. We investigated 35 primary colorectal cancers resected surgically, 27 hepatic metastases and 8 lung metastases from colorectal carcinoma. TdRPase was highly expressed in primary colorectal cancer with lung metastases (100.0%) and surgically resected lung metastases cancer (87.5%). The staining correspondence between primary colorectal cancer and metastases was 19 cases (70.4%) in the liver metastases and 7 cases (87.5%) in the surgically resected lung metastases. The above results suggested that immunohistochemical staining for primary colorectal cancer may provide information about the sensitivity of metastases to the chemotherapy.

Adult↗
PubMed1998

[Prognostic significance of loss of heterozygosity in breast cancer].

Loss of heterozygosity (LOH) was analyzed in 113 cases of sporadic breast cancer using 35 microsatellite markers on 20 chromosomes. LOH was frequently seen in 17p (44%), 16q (31%), 17q (29%) and 13q (23%). Individual patients were scored according to the incidence of LOH at the above four chromosomal markers; with no LOH as 1, with one or two LOH as 2, and with three of four LOH as 3. A high LOH score was well associated with high histological grade (p = 0.019) and a significantly poor prognosis (p = 0.0035). These data suggest that accumulation of LOH occurs at a later stage of breast cancer progression, and that the LOH score may be a useful prognostic marker of breast cancer.

Breast Neoplasms↗
PubMed1998

[Method of preventing hepatic artery occlusion during continuous intrahepatic arterial infusion chemotherapy of 5-FU].

A randomized clinical trial of combined use of steroids, which have a vascular endothelium-protecting action, was performed to develop a method to prevent hepatic artery occlusion during continuous intrahepatic arterial infusion chemotherapy with 5-FU. The steroid used was dexamethasone palmitate (Limethason), which has a high rate of uptake by endothelial cells. The 24 patients with advanced colorectal cancer were divided into 2 groups randomly and both were treated with 5-FU 250 mg/day by continuous hepatic arterial infusion for three weeks. The weekly dose was 5-FU 7 V (1,750 mg) adjusted to 50 ml with physiological saline in Group A and 5-FU 7 V (1,750 mg) adjusted to 50 ml with Limethason 1 A (4.0 mg of dexamethasone palmitate) in Group B. The reservoir was replaced every week. No changes in the mixture (appearance, pH, granule diameter, dexamethasone palmitate content) were observed up to one week. Hepatic arterial stenosis was observed in 8 cases in Group A (67%), but was not observed in any of the cases in Group B. The above results indicated that Limethason has a preventive effect against hepatic artery occlusion.

Anti-Inflammatory Agents↗
PubMed1998

[Clinical value of gene diagnosis in breast cancer].

Gene diagnosis has been mainly performed for three purposes, 1) to assess the prophylactic risk from genetic alterations of candidate gene, 2) to confirm the diagnosis from a small volume of cancer cells using polymerase chain reaction method and 3) to understand the biological characteristic of the tumor by assessing genetic instabilities. BRCA1 and BRCA2 are quite important candidate genes in familial breast cancer. Recently, prophylactic mastectomy has been performed for BRCA1/2 carriers in Western countries. Telomerase activity can be a sensitive and definitive analysis for diagnosing certain cancers, and the reverse transcripted polymerase chain reaction (RT-PCR) method can detect a small number of metastatic cancer cells in the axillary lymph node. Furthermore, genetic abnormalities, such as abnormalities in oncogenes or/and tumor suppressor genes and loss of heterozygosity or microsatellite instability, facilitate understanding of the biological characteristics of these tumors. It is necessary for the clinician to understand the significance and usefulness of gene diagnosis.

Breast Neoplasms↗
PubMed1997

The Clinical Value of Microsatellite Instability and a Loss in Heterozygosity in Sporadic Breast Cancers.

We analyzed loss of heterozygosity (LOH) and microsatellite instability (MI) in 108 cases of sporadic breast cancers using 22 microsatellite markers on 12 chromosomes. LOH was frequently seen in 1p(13%), 6p(18%), 8p(11%), 11p(18%), 13q(21%),16q(31%), 17p(44%) and 17q(29%). Individual patients were scored according to the degree of LOH at the above eight chromosomal markers. Patients with no LOH were scored as 1, patients with one to three LOH were scored as 2, and patients with four or more LOH were scored as 3. A high LOH score correlated with a high histological grade (p=0.019) and a poor prognosis (p=0.0035). Eleven(10.2%) of 108 patients with breast cancer showed MI, with 6 cases showing MI at a single locus and 5 at multiple loci. Of the 11 MI-positive patients only one had lymph node involvement(p=0.015), none had histological grade 3 disease, and MI-positive patients tended to have a better prognosis than MI-negative ones. These data suggest that MI may be an early event in mammary tumorigenesis, and that LOH occurs at a later stage. The LOH score may be a useful prognostic marker of operable breast cancer.

Journal Article↗
PubMed1997

Immunohistochemical detection of human milk components aspirated in lungs of an infant.

We examined an autopsy case of an infant whose cause of death was suspected to be asphyxia due to human breast milk aspiration. In order to demonstrate aspirated milk in the lungs, we conducted immunohistochemical staining using eight antibodies against the components of human milk. Seven of the eight antibodies reacted positively with the substances suspected to be aspirated milk. We concluded that immunohistochemical staining with these antibodies is useful to demonstrate human milk aspiration and provide some keys for detecting the causes of unexpected infant deaths.

Autopsy↗
PubMed1997

Detection of sarin hydrolysis products from sarin-like organophosphorus agent-exposed human erythrocytes.

A sarin-like organophosphorus agent, [bis(isopropyl methyl)phosphonate; BIMP], was synthesized. This agent has the same phosphonate group as sarin and also has the same anti-acetylcholinesterase activity potency as sarin. The ID50 and LD50 values of BIMP in mice after intravenous injection were 3.9 nM and 0.8 mg/kg, respectively. The AChE activities of their red blood cells and brains were dose-dependently reduced by intravenous BIMP. After preparation of experimental BIMP-exposed human red blood cells, BIMP-bound acetylcholinesterase (AChE) was solubilized from erythrocyte membranes, purified by immunoaffinity chromatography, digested with trypsin, and the sarin hydrolysis products bound to AChE were released by alkaline phosphatase digestion. The digested sarin hydrolysis products were subjected to trimethylsilyl (TMS) derivatization and detected by gas chromatography-mass spectrometry. Isopropyl methylphosphonic- and methylphosphonic acids, which are the sarin hydrolysis products, were detected in experimental BIMP-exposed human red blood cells. This new method, which enables sarin's hydrolysis products to be detected in BIMP-exposed erythrocytes, is a useful tool for studying sarin-poisoning victims.

Acetylcholinesterase↗
PubMed1997

Alterations and Polymorphisms of the Estrogen Receptor Gene in Breast Cancer.

The existence of hormone-independent tumors is a substantial problem for the present endocrine treatment of breast cancers. Recently, numerous variant estrogen receptors (ERs) at the mRNA level have been detected with base pair insertions, transitions, and deletions, as well as alternative splicing, yielding deletion of exon 3, 5, or 7. It has been shown that the loss of hormone dependence in breast tumors is partly due to the presence of mutated or truncated ERs that can activate the transcription of an estrogen-regulatable gene in the absence of estrogen. The mechanism of the loss of hormone dependency is, however, still very complex. Thus, further work assessing the correlation between clinical behavior and ER variants is required to determine whether these variants play a role in hormone-resistant disease. Additionally, a possible linkage to the ER gene has been found in some breast cancer families, suggesting that either the ER gene itself or an adjacent gene may be breast cancer susceptibility genes.

Journal Article↗
PubMed1997

Structural determination of the O-linked sialyl oligosaccharides liberated from fetuin with endo-alpha-N-acetylgalactosaminidase-S by HPLC analysis and 600-MHz 1H-NMR spectroscopy.

The endo-alpha-N-acetylgalactosaminidase from the culture medium of Streptomyces sp. OH-11242 (endo-GalNAc-ase-S) hydrolyzed the O-glycosidic linkage between GalNAc and Ser (Thr) in fetuin, liberating oligosaccharides. The O-linked oligosaccharides liberated from the fetuin with endo-GalNAc-ase-S were pyridylaminated following fractionation on a Bio-Gel P-4 column. The structure of the pyridylaminated O-linked oligosaccharides from fetuin has been determined by reverse-phase HPLC and 600-MHz 1H-NMR spectroscopy. The chemical shifts and the coupling constants of pyridylaminated (PA) NeuAc alpha2-3Gal beta1-3GalNAc were refined by computer simulation of the spectrum. The structures of NeuAc alpha2-3Gal beta1-3(NeuAc alpha2-6)GalNAc-PA and NeuAc alpha2-3Gal beta1-3(NeuAc alpha2-3Gal beta1-4GlcNAc beta1-6)GalNAc-PA were determined by their structural reporter groups.

Animals↗
PubMed1997

Formation of leukotoxin (9,10-epoxy-12-octadecenoic acid) during the autoxidation of phospholipids promoted by hemoproteins.

Myoglobin (Mb) and cytochrome c (Cyt c) are known to promote lipid peroxidation when mixed with certain types of phospholipids. In the presence of phospholipids such as cardiolipin (CL), ferrous Mb and Cyt c were converted to ferric hemoproteins, and autoxidation of the phospholipids and the oxidation of free linoleic acid (LA) added to the reaction mixture were observed. When the reaction mixture comprising 0.01 mM Cyt c, 0.2 mM CL and 0.1 mM LA was incubated, 92.7% of LA was consumed, and the LA products included 2.49 microM 9,10-epoxy-12-octadecenoic acid (leukotoxin) and its isomer which are potent inhibitors of mitochondrial respiration and have toxic effects on cardiac function. Hemoglobin (Hb) could promote almost no lipid peroxidation in the presence of any kinds of phospholipids. The experiments using some scavengers of active oxygen species revealed that tocopherol and ascorbic acid could strongly reduced LA oxidation caused by Cyt c or Mb. As LTx production was also observed when LA was mixed with Fe2+, LTx may be a common product where non-enzymatic lipid peroxidation occurs.

Cardiolipins↗
PubMed1997

Effect of monochlorohydrins of linoleic acid on guinea-pig cardiac papillary muscles.

The hydrogen peroxide (H2O2)-myeloperoxidase system can convert linoleic acid (LA) to monochlorohydrins. LA monochlorohydrins can also be produced when LA monoepoxides are subjected to low pH solutions. We chemically synthesized and purified LA monochlorohydrins and examined their effect on the developed tension of guinea-pig papillary muscles in vitro in terms of both concentration and the duration of exposure. A decrease in muscular tension was observed immediately after addition of LA monochlorohydrins at concentrations of 30, 100, and 300 microM. We also compared the effect of LA monochlorohydrins on muscle tension with those of LA monoepoxides.

Animals↗
PubMed1997

Cleavage of amino acid residue(s) from the N-terminal region of alpha A- and alpha B-crystallins in human crystalline lens during aging.

The current study reports for the first time a post-translational modification at the N-terminal region of alpha A- and alpha B-crystallins in normal human lens. The post-translational modification involves a loss of amino acid residues from the N-terminal region. We found three types of losses of N-terminal amino acid(s) from alpha-crystallin. One is the loss of the N-terminal amino acid residues 1-3 from alpha A-crystallin in aged lenses of the age 70 group. The other two modifications were found in alpha B-crystallin. One is the loss of Met(1) of the N-terminus and the other is the loss of 6 amino acids from the N-terminal region. These phenomena were observed in the lenses > 40 age group. Recent studies suggest that the N-terminal region of alpha-crystallin may play a chaperone-like role at the molecular level. These losses of amino acids from the N-terminal region may affect this molecular chaperone-like activity as well as the transparent properties of the human lens.

Aging↗
PubMed1997

Definitive evidence for the acute sarin poisoning diagnosis in the Tokyo subway.

A new method was developed to detect sarin hydrolysis products from erythrocytes of four victims of sarin (isopropylmethylphosphonofluoridate) poisoning resulting from the terrorist attack on the Tokyo subway. Sarin-bound acetylcholinesterase (AChE) was solubilized from erythrocyte membranes of sarin victims, digested with trypsin, the sarin hydrolysis products bound to AChE were released by alkaline phosphatase digestion, and the digested sarin hydrolysis products were subjected to trimethylsilyl derivatization and detected by gas chromatography-mass spectrometry. Isopropylmethylphosphonic acid, which is a sarin hydrolysis product, was detected in all sarin poisoning, victims we examined and methylphosphonic acid, which is a sarin and soman hydrolysis product, was determined in all victims. Postmortem examinations revealed no macroscopic and microscopic findings specific to sarin poisoning and sarin and its hydrolysis products were almost undetectable in their blood. We think that the procedure described below will be useful for the forensic diagnosis of acute sarin poisoning.

Acetylcholinesterase↗
PubMed1997

Clinical significance of bcl-2 gene expression in human breast cancer tissues.

The expression of estrogen receptor (ER) and bcl-2 (Bcl-2), an apoptosis protective oncogene, in normal and cancerous breast duct epithelia was immunohistochemically examined in fresh frozen tumor tissues from 142 Japanese breast cancer patients. The clinico-pathological characteristics and the disease free survival of the patients were analyzed. The expression of both the proteins was also observed in intraductal components of breast cancer. Although less than 1% of normal duct epithelia expressed ER, Bcl-2 was diffusely expressed. The expression of both these proteins in breast cancer significantly correlated with each other. Their expression significantly correlated negatively with tumor size but not with lymph node status. The papillo-tubular sub-type of invasive ductal carcinoma expressed Bcl-2 significantly more frequently than the solid-tubular sub-type. Patients with Bcl-2 expressing tumors survived without recurrence significantly more than those with tumors exhibiting reduced expression. Papillary-cribriform type intraductal components expressed both those proteins more often than the solid-comedo type.

Adult↗
PubMed1997

Characterization of monoclonal antibody reactive with 10-hydroxy-12(Z)-octadecenoic acid (10-OHODA) and its demonstration in cultured human macrophages.

10-Hydroxy-12(Z)-octadecenoic acid (10-OHODA) has an inhibitory effect on the tension of papillary muscles in isolated guinea-pig hearts. To establish an immunoassay for 10-OHODA a mouse monoclonal antibody (MoAb), YM-1, was produced. In order to evaluate the ability of this MoAb to recognize various 10-OHODA analogs including leukotoxin (9, 10-epoxy-12-octadecenoic acid, LTx), a sensitive enzyme-linked immunosorbent assay (ELISA) was developed using the avidin-biotin complex (ABC). The detection limit for 10-OHODA was as low as 0.5 ng in this system. In order to demonstrate the presence of 10-OHODA in living cells, macrophages derived from the human leukemia cell line THP-1 by adding 160nM phorbol 12-myristate 13-acetate (PMA) were exposed to 95% O2, and 5% CO2 for 24 h. 10-OHODA and other fatty acids were extracted from the exposed macrophages with diethylether after phospholipase A2 treatment. The 10-OHODA content was determined using the new ELISA, and 18.5 ng 10-OHODA was detected in the macrophages exposed to the high oxygen concentration (1 x 10(6) cells).

Animals↗
PubMed1997

Death due to a methane gas explosion in a tunnel on urban reclaimed land.

Studies of four male victims who were killed in an accidental tunnel gas explosion on urban reclaimed land are described. The studies were judicial autopsy examinations to determine the precise causes of death. Two men died of carbon monoxide intoxication, one died of massive brain damage, and the fourth died of drowning. The concentrations of methane in several organs were much lower than the lethal level, whereas those in adipose tissue were relatively high. These findings indicated that a low concentration of methane was almost always present in the atmosphere at the construction site. Recently, coal mine accidents have been decreasing in Japan. However, there is still a possibility of underground explosions or gas leaks in confined spaces other than coal mines. To determine the precise cause of death in such cases, careful autopsies and other examinations should be performed using methods similar to those used in coal mine accidents.

Adult↗