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Biomedical subjects

H Yoshimura

Publications and source records attributed to H Yoshimura.

At least 271 records · Page 15Linked to original sources
PubMed1992

Pulmonary blastoma. Comparison between its epithelial components and fetal bronchial epithelium.

Three cases of pulmonary blastoma exhibiting biphasic epithelial and stromal patterns, and a case of fetal lung-type adenocarcinoma, were examined by immunohistochemistry and electron microscopy (EM) and compared with fetal bronchial epithelium in order to explore the multidirectional differentiation of their epithelial components. The glandular cells of all four tumors resembled fetal bronchial epithelial cells in the pseudoglandular stage. Neuroendocrine (NE) cells were also present; they were argyrophilic and expressed pan-NE markers, neurosecretory granules and peptide hormones. The neural cell adhesion molecule (NCAM) was strongly expressed on the cell membranes of glandular cells, as in the case of proximal bronchial epithelial cells at the pseudoglandular stage in fetal lung. Sialosylated Lewis X was also expressed, indicating that the epithelial cells were possibly of endodermal origin. Two of the four cases showed considerable immunoreactivity for alpha-fetoprotein (AFP). The epithelial cells of pulmonary blastomas may occasionally de-differentiate into cells functionally resembling fetal hepatic, foregut and yolk sac cells expressing AFP. Tumor examination by immunohistochemistry and EM suggested that the glandular cells of the tumors may differentiate to some extent like those of fetal large bronchi at the pseudoglandular stage, but there was concordance and discordance in the expression of neuroendocrine and oncofetal markers between blastomatous tumors and fetal bronchial epithelium.

Aged↗
PubMed1992

Sex difference in hepatic microsomal aldehyde oxygenase activity in different strains of mice.

Hepatic microsomal oxidation of 11-oxo-delta 8-tetrahydrocannabinol (11-oxo-delta 8-THC) and 9-anthraldehyde (9-AA) to the corresponding carboxylic acids was investigated using six strains of male and female mice (ddN, ddY, C57BL, DBA, C3H and ICR). No significant sex difference was observed in the activity toward 11-oxo-delta 8-THC except for ICR, whereas the activity toward 9-AA was significantly higher in female than in male of ddN, C57BL, DBA and C3H mice. The present study suggests that female specific form(s) of cytochrome P450 may be responsible at least in part for the microsomal oxidation of 9-AA, but not that of 11-oxo- delta 8-THC.

Aldehyde Oxidase↗
PubMed1992

[Studies on cell proliferation activities in acute toxic lesions in the liver and pancreas of hamsters treated with N-nitrosobis(2-oxopropyl)amine].

Histopathology and cell proliferation activities in acute toxic lesions in the liver and pancreas of female Syrian hamsters given a S.C. injection of N-nitrosobis(2-oxopropyl)amine (BOP) at a dose of 100 mg/kg, were investigated. Histologically, at one day after administration, hypertrophy and focal necrosis of the hepatocytes were observed, whereas no remarkable changes were seen in the pancreas. At 7 days after administration, when diffuse hypertrophy, vacuolation and necrosis of the hepatocytes, and atypical hyperplasia of the bile duct were seen in the liver, hyperplasia of the pancreatic duct and focal necrosis and vacuolation of the acinar cells were noticed in the pancreas. Immunohistochemistry for both 5-bromodeoxyuridine (BrdU) and proliferating cell nuclear antigen (PCNA) revealed remarkable increases of cell proliferation activities in the target cells for BOP toxicity, especially at 7 days after BOP treatment. Meanwhile, the number per nucleus of silver-stained proteins related to nucleolar organizer regions (AgNOR) was significantly increased in the target cells at both 1 and 7 days after BOP treatment. Thus, in the present study, it was suggested that acute toxic changes in the liver of hamsters treated with BOP precedes those in the pancreas. The speculation that AgNOR may be an indicator recognizing earlier alterations on acute BOP toxicity remains to be examined.

Animals↗
PubMed1992

[A case of hydropneumothorax].

A 19-year-old girl was admitted because of fever, cough and suddenly occurred chest pain. One month earlier she had experienced a fever and cough, then she had felt sudden chest pain 2 weeks prior to the admission. A chest X-ray showed left pneumothorax and massive pleural effusion. A diagnosis of hydropneumothorax was made. In spite of the chest tube drainage, reexpansion of the lung was unsatisfactory. Thoracotomy and decortication of the lung resulted in good reexpansion. Histological finding revealed pleuritis due to bacterial peribronchial infection, which resulted in hydropneumothorax, namely an abscess ruptured to the pleural cavity.

Adult↗
PubMed1992

Regiochemical differences in cytochrome P450 isozymes responsible for the oxidation of methylenedioxyphenyl groups by rabbit liver.

The cytochrome P450 isozymes catalyzing the oxidation of the methylenedioxyphenyl compounds methylenedioxybenzene (MDB) and methylenedioxyamphetamine (MDA) have been investigated in rabbit liver preparations. The aromatic ring in MDB undergoes both demethylenation to catechol and aromatic hydroxylation to sesamol, whereas that in MDA undergoes only demethylenation to dihydroxyamphetamine. Formation of catechol and sesamol from MDB in microsomal incubation mixtures was enhanced about 5- and 3-fold, respectively, by pretreatment of the rabbits with phenobarbital, which induced CYP2B4 and CYP4B1. The cytochrome P450 isozyme responsible for aromatic hydroxylation of MDB was induced by beta-naphthoflavone and was inhibited by alpha-naphthoflavone. Microsomal demethylenation of MDA was minimally sensitive to pretreatment of the rabbits with phenobarbital, beta-naphthoflavone, pyrazole, or rifampicin. However, MDA competitively inhibited the N-demethylation of erythromycin. Antibodies against CYP2B4, but not those against CYP4B1, caused a marked inhibition of the demethylenation and aromatic hydroxylation of MDB. Antibodies against CYP2C3 did not inhibit the demethylenation of MDA, nor did substrates or inhibitors of the CYP2D family except for bufuralol. MDB and MDA were both capable of forming metabolic intermediate complexes, and the rate of complex formation was accelerated by phenobarbital induction. Reconstitution experiments with CYP2B4 suggested that phenobarbital-inducible complex formation from MDA was not due to the carbene pathway involving the methylenedioxy group but was due to oxidation of the amino group. These results indicate that CYP2B4 oxidizes different regions of methylenedioxyphenyl compounds depending on their structure. MDB undergoes oxidation at the methylenedioxy group (major) and the benzene ring (minor). MDA is oxidized at the alkylamino side chain at the nitrogen and alpha-carbon. The results suggested that one or more constitutive isoforms (probably unknown) of cytochrome P450 present in rabbit liver microsomes are primarily responsible for MDA demethylenation but that CYP3A6 contributes slightly.

3,4-Methylenedioxyamphetamine↗
PubMed1992

[Myocardial infarct size and left ventricular function in diabetic patients].

We determined the relationship between myocardial infarct size (MIS) estimated by electrocardiographic measurements of infarct size (QRS score) and left ventricular function estimated by angiographically left ventricular ejection fraction (EF). MIS estimated by QRS score were the same in both DM and NDM (5.2 +/- 0.5 vs 4.3 +/- 0.4: p greater than 0.05), but EF in DM was significantly lower than in NDM (43.1 +/- 1.4 vs 51. +/- 1.1%: p less than 0.05). There was clear linear correlation between MIS and EF in NDM (r = -0.71) but not in DM. EF was much lower in DM than in NDM even at the same QRS score level. There were no differences in blood pressure, serum lipid levels, age, and the site of the myocardial infarction. The most likely explanation for this appears to be due to a previous left ventricular disease in DM.

Aged↗
PubMed1992

[Metabolite of 15-p-iodophenyl-3(R,S)-pentadecanoic acid (123I) in blood and urine].

We analyzed metabolites of 123I-BMIPP in blood and urine using rats, rabbits and human, while human samples were obtained from normal volunteers of Phase I clinical study. We estimated metabolic pathway of 123I-BMIPP as a myocardial metabolic imaging agent. Radioactivity accumulated in heart after administration gradually decreased and was mainly excreted to bladder via kidneys. The main radioactive component in blood was 123I-PIPA for any species and the urinary components were metabolic conjugates of 123I-PIPA. As results of these studies, we considered that 123I-BMIPP was metabolized to 123I-PIPA by alpha-oxidation process for the first step, follow by beta-oxidation process, then 123I-PIPA was released to blood from tissues. Moreover, 123I-PIPA in blood was conjugated with other compounds and excreted to the bladder.

Animals↗
PubMed1992

[Slow releasing anticancer drug containing CDDP for intraoperative use in residual cancer cells].

We have already reported the slow releasing property and anticancer effect of Plachitin, which is reconstituted by combination of CDDP and chitin. This study deals in more detail with the slow releasing property, and the renal complications and the effectiveness for solid tumor were examined. After implantation of Plachitin subcutaneously in the abdominal wall, the platinum concentration in the different organs was measured. In the abdominal muscle around the implanted Plachitin, a high concentration of platinum was maintained until 8 weeks and the peak was 4 weeks after implantation. At the same time, the serum concentration of platinum remained low. In kidney, the platinum concentration resembled the levels in the abdominal muscle, but no renal dysfunction was found serologically or histologically. When Plachitin was implanted around the solid tumor, the survival rates were improved and the gain in tumor weight was suppressed as compared with the controls. From these findings, Plachitin seemed to be effective as a slow releasing anticancer drug for topical application.

Animals↗
PubMed1992

[Five cases of Crow-Fukase syndrome].

We presented five cases of Crow-Fukase syndrome. Plasma cell hyperplasia or dyscrasia in bone marrow were recognized in all cases and localized bone lesion was seen in three cases. Thyroid dysfunction was seen in three cases; hyperthyroidism in one case and hypothyroidism in two cases, which was considered to be one of the characteristics though it has seldom been described in this disease. Two of four cases treated with prednisolone had good responses but two cases treated with interferon had no effect.

Adult↗
PubMed1992

Lymphocyte-mucosal interaction of the middle ear mucosa.

The middle ear mucosa possesses immunologic features similar to those of the peripheral mucosa sites in the common mucosal immune system and after mucosal immunization, antigenspecific IgA-forming cells appear in the inflamed mucosa of the tympanic cavity. Recent investigations suggest that lymphocyte migration to lymphoid tissues is regulated by lymphocyte-high endothelial venules (HEV) interaction. However, the lymphocyte migration mechanism to the middle ear mucosa is still unclear. We investigated whether or not organ-specific determinants which lymphocytes bind with are present on the middle ear mucosa by in vivo and in vitro lymphocyte adherence assays by using fluorescein-labeled lymphocytes from various lymphoid tissues. Many lymphocytes from Peyer's patches and hilar lymphnodes adhered on the inflamed middle ear mucosa with or without mucosal immunization, while these cells were not found on the normal tympanic mucosa. The number of the cells was smaller than that in the gastrointestinal mucosa. Lymphocyte adherence to the middle ear mucosa was not suppressed by anti-T cell antibody. These findings suggest that the middle ear mucosa possesses organ-specific mucosal determinants which B-lymphocytes selectively bind with, and that those determinants which regulate lymphocyte migration to the middle ear mucosa differ from those of other mucosae in the gastrointestinal tract.

Animals↗
PubMed1991

[Enzymatic iodination of thyroglobulins obtained from patients with thyroid disease].

Iodination of the isolated thyroglobulin (Tg) by peroxidase was compared with various Tg preparations obtained from patients with thyroid diseases. For the purpose, the iodination process was observed in the incubation medium containing Tg, iodide, H2O2-generating system, and thyroid peroxidase (TPO) or lactoperoxidase (LPO). During the incubation, iodination of Tg preparations increased gradually and reached a plateau after 90 min., and 5 min. incubation with 3mIU or 14mIU of TPO, respectively. The degree of iodination level at the plateau region was different in each Tg preparation, depending on the iodine content of the original starting (native) preparation before incubation. The iodination level of cancer Tg with a very low iodine content (less than 0.1%) was low compared with the normal Tg level (obtained from normal thyroid tissue which contained about 0.4% iodine). The above findings suggest the possible existence of some structural differences of Tg in terms of the susceptibility to the iodination between the preparations of normal and diseased Tgs. As far as the immunological aspect concerned, there was no significant difference in the affinity (avidity) of Tg with polyclonal anti-Tg antibody between the native Tg and the enzymatically iodinated one. These results suggest that the changes of iodine and thyroid hormone contents of Tg by in vitro iodination, has no significant effect on the immunological property of Tg molecule.

Antigen-Antibody Reactions↗
PubMed1991

Catalytic activity of cytochrome P450 isozymes purified from rat liver in converting 11-oxo-delta 8-tetrahydrocannabinol to delta 8-tetrahydrocannabinol-11-oic acid.

Cytochrome P450 isozymes purified from rat hepatic microsomes were able to catalyse the oxidation of 11-oxo-delta 8-tetrahydrocannabinol (11-oxo-delta 8-THC) to delta 8-THC-11-oic acid in the presence of NADPH, cytochrome P450 reductase and dilauroylphosphatidylcholine. The catalytic activities (nmol/min/nmol P450) of cytochrome P450s, UT-2 (IIC11), UT-4 (IIA2), UT-5 (IIC13), PB-1, PB-2 (IIC6), PB-4 (IIB1), MC-1 (IA2), MC-5 (IA1) and IF-3 (IIA1), were 0.69, 0.08, 0.07, 0.23, 0.46, 0.02, 0.06, 0.07 and 0.34, respectively, whereas the activities of cytochrome P450s, PB-5 (IIB2) and DM (IIE1), were less than 0.02 nmol/min/nmol P450. Cytochrome P450 IIC11 showed the highest catalytic activity of the cytochromes examined. The mechanism for the oxidation of 11-oxo-delta 8-THC to delta 8-THC-11-oic acid by cytochrome P450 IIC11 was established as being an oxygenation since one atom of oxygen-18 was exclusively incorporated into the carboxylic acid formed under 18O2. The antibody raised to cytochrome P450 IIC11 inhibited by 60% the hepatic microsomal oxidation of 11-oxo-delta 8-THC to delta 8-THC-11-oic acid in male rats. These results indicate that cytochrome P450 IIC11 is a major form of the cytochrome to catalyse the oxidation of 11-oxo-delta 8-THC to delta 8-THC-11-oic acid in the hepatic microsomes of male rats and that the oxidation of aldehyde to carboxylic acid is a catalytic activity common to most isozymes of P450.

Animals↗
PubMed1991

Ethopharmacology of maternal aggression in mice: effects of diazepam and SM-3997.

The present study investigated whether there is any difference between the effects of benzodiazepine and non-benzodiazepine anxiolytics on maternal aggression in lactating mice, using an ethological technique. We used SM-3997, a 5-HT1A receptor ligand, as a non-benzodiazepine anxiolytic. Behavior towards an intruder male mouse was assessed on postpartum days 5 and 7 in female mice that had been housed alone since the end of the 4-day mating period. Acute oral administration of diazepam had a biphasic effect on the frequency of bites: 1 mg/kg diazepam significantly increased bite frequency, while 2.5 mg/kg diazepam significantly decreased it. However, 2.5 mg/kg diazepam also caused a significant decrease in locomotor activity. In contrast, SM-3997 (1, 2.5 and 5 mg/kg p.o.) significantly decreased the frequency of bites in a dose-dependent manner without causing motor dysfunction. Chronic treatment with 5 mg/kg SM-3997 significantly decreased the frequency of bites when compared with vehicle, whereas diazepam was ineffective at the doses used (0.5 and 1 mg/kg p.o.). The findings suggest that the proaggressive effect is specific to benzodiazepines, and that 5-HT1A receptors may be involved in the suppression of maternal aggression in mice.

Aggression↗
PubMed1991

Structural and functional analysis of a polyoma-related mammalian plasmid (L factor): the enhancer activity and plasmid establishment.

L factor is a unique plasmid DNA which was originally discovered in a subclone (B822) of mouse L cells at a high copy number (more than 5,000 copies/cell). The presence of L factor caused no detectable abnormalities to the plasmid-bearing cells. We determined the total DNA sequence of the L factor I (and a part of L factor II) and compared it with that of polyoma DNA. Both DNA are common to the general construction of DNA frames such as early, late and noncoding regions, suggesting the two to be closely related. On the other hand, the L factor DNA sequences differ substantially from that of polyoma in the DNA sequences corresponding to the polyoma large T antigen, capsid proteins and a portion of the enhancer region. In order to investigate the mechanism of plasmid establishment of L factor, we compared the enhancer activity, capacity of DNA replication and efficiency of plasmid establishment of L factor with those of polyoma. The results indicate that L factor enhancer activity and DNA replication capacity were considerably lower than those of polyoma, suggesting that these altered (lowered) activities associated with L factor contribute to the plasmidal establishment and stable maintenance of L factor.

Animals↗
PubMed1991

Monolayer crystallization of flagellar L-P rings by sequential addition and depletion of lipid.

The L-P ring complex is thought to be a molecular bushing that supports flagellar motor rotation at about 10,000 revolutions per minute with presumably very little friction. Structural studies of this complex have been limited because only very small amount of samples are available. Therefore devising an efficient method of crystallization was essential. The addition of a phospholipid and its subsequent slow depletion by phospholipase A2 have been used to successfully grow well-ordered monolayer crystals that extend up to about 10 micrometers. The interaction of the L-P ring complex with lipid membranes was also visualized during this process.

Cell Fractionation↗
PubMed1991

A constitutive form of guinea pig liver cytochrome P450 closely related to phenobarbital inducible P450b(e).

In order to provide evidence that a cytochrome P450 belonging to the IIB subfamily is expressed as a constitutive form in the guinea pig, we tried to purify an isozyme from liver microsomes of untreated guinea pigs by assessing its reactivity with anti-P450b antibody in the present study. One form of cytochrome P450, named P450GP-1, was obtained. The minimum molecular weight of this isozyme was estimated to be 52,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The amino terminal sequence up to the 33rd amino acid of P450GP-1 was determined. As expected, comparison of the amino acid sequence with those of cytochrome P450 isozymes from other species reported so far indicated that P450GP-1 was highly homologous to P450s categorized in the IIB subfamily; that is, 67% similarity to rat P450b, 82% to rabbit LM2, 76% to dog PBD-2, 70% to mouse pf 3/46, and 73% to human IIB1. On the other hand, P450GP-1 showed only low similarity, less than 41%, to other cytochrome P450s of the II subfamily and those of the I, III, and IV families. Affinity of P450GP-1 to anti-P450b immunoglobulin G was confirmed to be comparable with that of a principal antigen, P450b. Immunoblot analysis revealed that P450GP-1 in the guinea pig liver microsomes was induced by phenobarbital treatment, but the increase was not as large as in the rat. P450GP-1 efficiently catalyzed benzphetamine N-demethylation, strychnine 2-hydroxylation, and testosterone 16 beta-hydroxylation, all of which are also catalyzed by P450b. Based on these results, it was strongly suggested that the IIB-type of cytochrome P450 in guinea pigs, at least one of them, is a constitutive form which is moderately induced by phenobarbital.

Amino Acid Sequence↗
PubMed1991

Sex difference in the oxidative metabolism of delta 9-tetrahydrocannabinol in the rat.

Oxidative metabolism of delta 9-tetrahydrocannabinol (THC), one of the major components of marihuana, was studied using liver microsomes of adult male and female rats. There was no significant difference in the rates of the cannabinoid oxidation in terms of nmol per min per nmol of liver microsomal cytochrome P450 or of nmol per min per mg of microsomal protein between male and female rats. delta 9-THC was biotransformed to various metabolites including 11-hydroxy-delta 9-THC (11-OH-delta 9-THC), 8 alpha-OH-delta 9-THC, 8 alpha,11-diOH-delta 9-THC, 3'-OH-delta 9-THC by liver microsomes of male rats, while it was oxidized selectively to 11-OH-delta 9-THC by liver microsomes of female rats. After intraperitoneal administration of delta 9-THC, various metabolites were again found in the liver of the male rat, while in the female rat oxidation of the methyl group at the 9-position was a major metabolic pathway. These results demonstrate that an apparent sex-related difference exists in the oxidative metabolism of delta 9-THC in the rat.

Animals↗