Biomedical subjects

N Ohishi

Publications and source records attributed to N Ohishi.

At least 55 records · Page 3Linked to original sources

PubMed1996

Extensive pulmonary metastases in malignant pleural mesothelioma. A rare clinical and radiographic presentation.

We report a case of malignant pleural mesothelioma in a patient who presented with pleural effusion and reticulonodular shadow on chest radiograph. Pulmonary metastases were diagnosed by transbronchial lung biopsy specimen and the patient died of extensive pulmonary metastases. This pattern of clinical and radiographic presentation is seldom reported for malignant pleural mesothelioma.

Humans↗

PubMed1995

Amino-acid sequence and tissue distribution of guinea-pig leukotriene A4 hydrolase.

The guinea-pig leukotriene A4 hydrolase (LTA4H)-encoding cDNA was isolated from a guinea-pig lung cDNA library by cross-hybridization using a human probe. The deduced amino acid (aa) sequence consists of 611 aa (68 756 Da) and contains all twelve internal peptide and N-terminal sequences determined from the purified enzyme from guinea-pig intestine. The aa identity of the guinea-pig enzyme with its human, mouse and rat counterparts was 92.9, 90.5 and 90.4%, respectively. The previously characterized zinc-binding motif and a putative active site were highly conserved, supporting the aminopeptidase activity described for this enzyme. RNA blot analysis demonstrated ubiquitous expression of the LTA4H mRNA.

Amino Acid Sequence↗

PubMed1995

Construction and characterization of adenoviral vector expressing biologically active brain-derived neurotrophic factor.

To deliver brain-derived neurotrophic factor (BDNF) to the central nervous system, we sought to attain adenovirus-mediated transfer and expression of the gene in both in vitro and in vivo experiments. For this purpose, we constructed AxCA-BDNF, a recombinant adenoviral vector containing the BDNF cDNA expression cassette. Reverse transcription polymerase chain reaction analyses of the infected HeLa cells and the transduced mouse brain revealed successful expression of the BDNF gene both in vitro and in vivo. The results of a survival assay of chick dorsal root ganglion cells showed that the produced BDNF was biologically active. We consider, therefore, this newly constructed recombinant adenovirus to be a useful tool to deliver BDNF to degenerating neurons and to be applicable to gene therapy of neurodegenerative diseases and nerve trauma.

Adenoviridae↗

PubMed1995

Cationic multilamellar liposome-mediated gene transfer into primary myoblasts.

To transfer foreign genes into myoblasts in primary culture, we found cationic multilamellar liposomes to be a useful mediator. When the cells were transfected with 2 micrograms of the plasmid pRSV-luc encapsulated into 50 nmol of our cationic multilamellar liposomes that had been prepared from N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, dilauroyl phosphatidylcholine, and dioleoyl phosphatidylethanolamine in a molar ratio of 1:2:2, luciferase was expressed with high efficiency without cytotoxicity. When the cells were transfected with the plasmid pRSV-lacZ encapsulated into the same liposomes, 0.7% of the cultured myoblasts expressed beta-galactosidase without cytotoxicity. This is the first successful instance of introducing foreign genes into primary cultures of myoblasts by means of liposomes.

Animals↗

PubMed1995

Atherogenic change in the thoracic aorta of the senescence-accelerated mouse.

Biochemical and histological changes in the thoracic aorta of the senescence-accelerated prone mouse were examined in comparison with those of the senescence-accelerated resistant mouse. At 3 and 5 months of age, the lipid peroxide level in the thoracic aorta was higher in the former than in the latter. At 5 months of age, levels of both total cholesterol and triglycerides in the aorta were higher in the former than in the latter, and vice versa for the level of aortic phospholipids. At 5 months of age, the prone mice showed macrophage invasion beneath the endothelial cells of the thoracic aorta, whereas the resistant ones did not.

Aging↗

PubMed1995

[Solitary rectal carcinoma metastasis to the left hilar lymph nodes: a case report].

A 66-year-old woman was referred to this institution for treatment of hemoptysis, atelectasis of the left upper lobe, and marked hypoxia necessitating oxygen therapy. A low anterior resection of the rectum had been performed for rectal adenocarcinoma 6 years and 3 months before this admission, and was followed by another resection after a local recurrence 20 months later. Bronchoscopy revealed an endobronchial tumor obstructing the left upper lobe bronchus. Tissue from a transbronchial biopsy revealed metastatic rectal carcinoma of the endobronchial lumen. There was no evidence of local recurrence or metastasis to other organs. A left pneumonectomy and lymph node dissection were performed successfully. The postoperative course was uneventful, and the patient was discharged after marked improvement of the arterial blood gas results. The pathological diagnosis of a resected tissue specimen was metastatic adenocarcinoma of the left hilar lymph nodes with invasion of the left main bronchus and protrusion into the endobronchial lumen. The patient remained disease-free for 6 months. At that time, computed tomography of the chest disclosed small metastases in the right lung and chemotherapy was begun.

Adenocarcinoma↗

PubMed1995

Mepyramine, a histamine H1 receptor antagonist, inhibits the metabolic activity of rat and human P450 2D forms.

The interaction of antihistaminics, including mepyramine, with rat hepatic cytochrome P450s (P450s) was investigated. We first investigated mepyramine binding to eight forms of rat hepatic P450s. Mepyramine bound specifically to P450 2D1, which suggests that it inhibits P450 2D activity. Histamine H1 receptor antagonists (mepyramine, diphenhydramine, chlorpheniramine and triprolidine) inhibited the lidocaine 3-hydroxylation activity catalyzed by P450 2D1 but did not inhibit the testosterone hydroxylation activities catalyzed by P450s other than P450 2D forms. The Ki values of these antagonists for the catalytic activity of P450 2D1 were low and were similar to those of quinine and quinidine, which are specific inhibitors of P450 2D forms. The Ki value of mepyramine was especially low, at 34 nM. Furthermore, the effects of mepyramine on human P450 2D6 were investigated. Among the ten forms of human P450 expressed in yeast, mepyramine bound specifically to P450 2D6 in a binding assay. In human hepatic microsomes, mepyramine inhibited the debrisoquine 4-hydroxylation activity catalyzed by P450 2D6. These results indicate that histamine H1 receptor antagonists such as mepyramine are potent inhibitors of P450 2D forms because of their high affinity for these enzymes.

Animals↗

PubMed1995

Difference in effects of classic and phospholipid hydroperoxide glutathione peroxidases on liver lipid peroxide level in selenium-deficient rats.

When weanling male rats of the Wistar strain were fed a selenium-deficient diet, the activity of classic glutathione peroxidase (GPx) in liver cytosol decreased rapidly. In contrast, the activity of phospholipid hydroperoxide GPx (PHGPx) in the cytosol decreased only slowly. Despite the marked decrease in classic GPx activity, the lipid peroxide level in the liver did not change until 6 weeks after the start of the feeding, whereas the level was significantly increased by 9 weeks, by which time PHGPx activity and its protein level had markedly diminished. These data indicate that PHGPx is much more crucial than classic GPx in preventing the elevation of liver lipid peroxide level in selenium-deficient rats.

Animals↗

PubMed1994

Identification and subcellular localization of leukotriene A4-hydrolase activity in human epidermis.

The purpose of this study was to determine whether normal human epidermis could produce leukotriene B4 (LTB4) from leukotriene A4 (LTA4) ex vivo, and to localize this LTA4-hydrolase activity. Epidermis obtained by suction blister technique incubated with human polymorphonuclear cells, resulted in a 54% increase in LTB4 formation when compared to polymorphonuclear cells incubated alone. Furthermore, human epidermis transformed exogenous LTA4 into LTB4, and this reaction obeyed Michaelis-Menten kinetics with an apparent Km of 6 microM. Subcellular fractionation of homogenized epidermis localized the LTA4-hydrolase activity mainly in the 105,000 x g supernatant fraction (cytoplasmic fraction). This activity was inhibited by two inhibitors of LTA4-hydrolase (bestatin and captopril). Western blot analysis of the 105,000 x g fraction of homogenized epidermis and cultured keratinocytes supported the presence of a LTA4-hydrolase. Thus, normal human epidermis possesses LTA4-hydrolase activity which can transform exogenous LTA4 and polymorphonuclear cell-derived LTA4 into LTB4. The identification of LTA4-hydrolase in the cytoplasmic fraction of human epidermis indicates that epidermal cells may play a more active role in the enzymatic process leading to formation of the proinflammatory compound LTB4 than previously expected.

Blotting, Western↗

PubMed1994

Characterization of human airway epithelial cell leukotriene A4 hydrolase.

We have previously shown that human airway epithelial cells contain leukotriene A4 (LTA4) hydrolase activity. To characterize this activity further, airway epithelial cells, cultured to confluence, were disrupted by sonication and were fractionated at 15,000 and 100,000 x g. Enzymatic activity was assessed by incubating fractions with 15 microM LTA4 at 37 degrees C for 15 min. LTA4 hydrolase activity was present in the 15,000 x g and the 100,000 x g supernatants and was inactivated by heating at 56 degrees C or by pronase, as is the case for neutrophil LTA4 hydrolase. However, the epithelial cell enzyme had a slower time course for product generation and demonstrated a different dose-response relationship to substrate when compared with the neutrophil. Kinetic analysis revealed nonlinear plots for epithelial data, most consistent with an enzyme that has multiple active sites. Immunoblotting, performed with anti-neutrophil LTA4 hydrolase antibody, recognized two bands in epithelial cell 15,000 x g supernatant (M(r) of 69,000 and 110,000-115,000). When resolved by gel filtration chromatography, only the M(r) 69,000 protein had enzymatic activity. Anion exchange chromatography of epithelial cell samples revealed that LTA4 hydrolase and aminopeptidase activity did not co-elute, whereas one of three peaks of aminopeptidase activity did co-elute in chromatograms of neutrophil samples. Immunoblots of proteolytic digests of partially purified M(r) 69,000 protein from epithelial cells and neutrophils revealed different immunoreactive bands. The digest of the M(r) 110,000-115,000 protein revealed no immunoreactive bands. Repeat kinetic analysis on 179-fold purified epithelial LTA4 hydrolase again revealed that it lacked significant aminopeptidase activity and retained its unique kinetic properties.(ABSTRACT TRUNCATED AT 250 WORDS)

CD13 Antigens↗

PubMed1994

Changes in content of P450 isozymes in hepatic and renal microsomes of the male rat treated with cis-diamminedichloroplatinum.

1. The changes in the activity of drug-metabolizing enzymes and in the content of P450 isozymes in renal and hepatic microsomes after treatment of the male Sprague-Dawley rat with cis-diamminedichloroplatinum (Cisplatin, CDDP) were examined. 2. NADPH-P450 reductase activity in renal microsomes was significantly increased by treatment with CDDP, but lauric acid omega- and (omega-1)-hydroxylation activities of renal microsomes were not increased. 3. The level of P4502C23 was increased significantly and levels of P4504A2 and 4A8 tended to increase in renal microsomes. 4. In hepatic microsomes, lauric acid omega-hydroxylation activity was increased, but (omega-1)-hydroxylation activity was not. Levels of P4502C11 and 3A2, which are male-specific forms, were decreased, whereas levels of P4502A1, 2C7 and 2E1 were increased in hepatic microsomes. The levels of P4504A2 and 4A3 were increased by CDDP and the level of P4504A1 was not changed. Changes in the protein levels of P450 by CDDP were consistent with those in the mRNA levels reported previously (LeBlanc et al. 1992). 5. Male-specific forms in rat liver such as P4502C11 were decreased by CDDP, but those in the kidney such as P4504A2 was not. Therefore, CDDP has different influences on the regulation of hepatic and renal P450s.

Animals↗

PubMed1994

Interferon-beta endogenously produced by intratumoral injection of cationic liposome-encapsulated gene: cytocidal effect on glioma transplanted into nude mouse brain.

The cytocidal effect of endogenously produced human interferon-beta was tested on glioma transplanted into the brain of nude mice by intracranial injection of a cell suspension of human glioma cell line U251-SP. When plasmid pSV2IFN-beta, bearing the human interferon-beta gene, was encapsulated into cationic multilamellar liposomes composed of N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, dilauroyl phosphatidylcholine, and dioleoyl phosphatidylethanolamine in a molar ratio of 1:2:2 and injected intratumorally, human interferon-beta was produced in the tumor. The tumor completely disappeared if the injection was done shortly after the transplantation. Even when the tumor did not disappear, survival of the tumor-bearing nude mice was markedly prolonged. In control experiments made with normal brain having no glioma, interferon-beta was not detected.

Animals↗

PubMed1993

Regulation of renal cytochrome P450s by thyroid hormone in diabetic rats.

Effects of thyroid hormone treatment on renal P450 expression in the diabetic rats were investigated. Diabetes produced by streptozotocin induced CYP4A2 and P450 K-2 (similar form with CYP2C23) but not P450 K-4 (similar form with CYP4A8) and induced lauric acid hydroxylation activity. The serum thyroid hormone level was decreased with diabetes. Treatment of diabetic rats with thyroid hormone (T3) as well as with insulin reversed the increase in the levels of CYP4A2 and P450 K-2. Thyroidectomy also induced CYP4A2 and P450 K-2 in the rat kidney. The increase was reversed by treatment of thyroidectomized rats with T3. These findings suggest that expression of CYP4A2 and P450 K-2 in rat kidney is suppressively regulated by thyroid hormone and the decrease in thyroid hormone level in the diabetic state affects the levels of CYP4A2 and P450 K-2.

Animals↗

PubMed1993

Characterization of two P-450 isozymes placed in the rat CYP2D subfamily.

Two P-450s with debrisoquine 4-hydroxylation activity, designated P-450 UT-7 and UT-7b, were purified and partially purified, respectively, from hepatic microsomes of untreated male rats. Both purified P-450s with an apparent molecular weight of 49,000, were associated with another protein with an apparent molecular weight of 29,000 which was designated 29 k-protein. The CO-reduced spectra of both P-450 UT-7 and UT-7b showed a peak at 448 nm. The NH2-terminal amino acid sequences of P-450 UT-7 and UT-7b were the same as the amino acid sequences of CYP2D1 and CYP2D2 deduced from the cDNA, respectively, except for the lack of a terminal methionine for P-450 UT-7b. In a reconstituted systems, P-450 UT-7 and UT-7b catalyzed lidocaine 3-hydroxylation and N-deethylation in the presence of the 29 k-protein. The Km and Vmax values for lidocaine 3-hydroxylation were 3.6 microM and 0.50 nmol/min/nmol of P-450 for P-450 UT-7, and 3.6 microM and 0.93 nmol/min/nmol of P-450 for P-450 UT-7b, respectively. Antibody against P-450 UT-7, which also cross-reacted with P-450 UT-7b, inhibited lidocaine 3-hydroxylation in liver microsomes from untreated male rats, but had little effect on lidocaine N-deethylation. These findings suggested that lidocaine 3-hydroxylation in hepatic microsomes from untreated male rats was catalyzed by P-450 UT-7 and/or UT-7b.P-450 UT-7 not containing 29 k-protein was obtained as the non-absorbed fraction from hydroxylapatite HPLC. The activities of debrisoquine 4-hydroxylation as well as lidocaine 3-hydroxylation and N-deethylation in a reconstituted system with P-450 UT-7 without 29 k-protein were one-fifth of those of P-450 UT-7 containing 29 k-protein at the same substrate concentration. These findings suggested that the 29 k-protein was essential to express the maximal metabolic activities. However, the lidocaine metabolic activity in a reconstituted system with P-450 UT-7 containing 29 k-protein and in hepatic microsomes were not inhibited by 29 k-protein antibody.

Amino Acid Sequence↗

PubMed1993

Stabilization of egg phosphatidylcholine liposomes by the insertion of sulfatide.

The characteristic effects of sulfatide and its derivatives on the stability of small unilamellar vesicles of egg phosphatidylcholine liposomes in phosphate-buffered saline were investigated by measuring the leakage of carboxyfluorescein that had been entrapped in these vesicles. We found that both the sulfate group and a long acyl chain, such as lignoceric acid, of the sulfatide are essential for the stabilization. The sulfatide derivatives that contain a somewhat shorter acyl chain such as stearic acid had no effect to suppress the leakage of carboxyfluorescein. The galactose residue of sulfatide is not essential to suppress the leakage. 1H-NMR study using a paramagnetic shift reagent demonstrated that the distribution of phosphatidylcholine in the vesicles containing sulfatide is homogeneous, which seems to contribute to the stability of the membrane.

Animals↗

PubMed1993

Efficient gene transfer with less cytotoxicity by means of cationic multilamellar liposomes.

A simple procedure for the preparation of cationic multilamellar vesicles (MLV) consisting of N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, dilauroyl phosphatidylcholine, and dioleoyl phosphatidylethanolamine in a molar ratio of 1:2:2 was devised. When bacteriophage lambda DNA was encapsulated into these liposomes, entrapment efficiency was found to be nearly 100%, and digestibility of the DNA was less than 10%. Upon encapsulation of the plasmid pCH110 into cationic MLV, efficient expression was comparable to that obtained with cationic vesicles prepared by reverse-phase evaporation method (REV). Cytotoxicity of the present liposomes was less than that of cationic REV and far less than that of Lipofectin.

Animals↗

PubMed1993

Generation of hydroxyl radical from lipid hydroperoxides contained in oxidatively modified low-density lipoprotein.

When low-density lipoprotein (LDL) was oxidatively modified and incubated with an epinephrine-FeCl3 mixture, an electron spin resonance spectrum characteristic of the spin adduct of 5,5-dimethyl-1-pyrroline-N-oxide and hydroxyl radical (DMPO-OH) was obtained. The amount of DMPO-OH formed increased with an increase in the concentration of lipid hydroperoxides contained in the oxidatively modified LDL. These results indicate that oxidatively modified LDL would generate hydroxyl radicals in vivo if an appropriate iron chelate were present and that the cytotoxicity of oxidatively modified LDL is ascribable, at least in part, to its capability to generate such radicals.

Animals↗

PubMed1993

Immunological differentiation between novel monomeric and classic tetrameric rat liver glutathione peroxidases.

Difference between a novel monomeric enzyme and the classic tetrameric enzyme of glutathione peroxidase in rat liver was examined immunologically. The polyclonal antibody raised against the novel enzyme reacted with the novel enzyme, but not with the classic enzyme. Likewise the anti-classic enzyme antibody reacted with the classic enzyme, but not with the novel one. The activity of the novel enzyme was decreased by the treatment with the anti-novel enzyme antibody, but not with the anti-classic enzyme antibody, and vice versa for the classic enzyme. Thus the novel monomeric glutathione peroxidase is a protein immunologically distinct from the classic enzyme.

Animals↗