Biomedical subjects

M Uchida

Publications and source records attributed to M Uchida.

At least 91 records · Page 5Linked to original sources

PubMed2000

N-Glycans protect proteins from protease digestion through their binding affinities for aromatic amino acid residues.

It was previously revealed [Yamaguchi, H., Nishiyama, T., and Uchida, M. (1999) J. Biochem. 126, 261-265] that N-glycans of both the high-mannose and complex types have binding affinity for aromatic amino acid residues. This study shows that free N-glycans protect proteins from protease digestion through their binding affinities for the aromatic amino acid residues exposed on protein molecules. Protease digestion of bovine pancreatic RNase A and bovine a-lactalbumin was depressed in solutions (1 mM or so) of free N-glycans of both the high-mannose and complex types. The increasing order of the protective effects of the N-glycans paralleled that of their affinities for aromatic amino acid residues; and the presence of aromatic amino acids practically abolished the protective effects of the N-glycans. The N-glycans also depressed the protease digestion of metallothionein, an aromatic amino acid-free protein, in agreement with the observation that the N-glycans also interact with the solvent-exposed aromatic amino acid residues of the proteases. Thus it seems probable that the N-glycans protect proteins from protease digestion by steric hindrance attributable to their binding affinity for the solvent-exposed aromatic amino acid residues of both substrate proteins and proteases.

Amino Acids↗

PubMed2000

Responses of wild watermelon to drought stress: accumulation of an ArgE homologue and citrulline in leaves during water deficits.

Wild watermelon from the Botswana desert had an ability to survive under severe drought conditions by maintaining its water status (water content and water potential). In the analysis by two-dimensional electrophoresis of leaf proteins, seven spots were newly induced after watering stopped. One with the molecular mass of 40 kilodaltons of the spots was accumulated abundantly. The cDNA encoding for the protein was cloned based on its amino-terminal sequence and the amino acid sequence deduced from the determined nucleotide sequences of the cDNA exhibited homology to the enzymes belong to the ArgE/DapE/Acy1/Cpg2/YscS protein family (including acetylornithine deacetylase, carboxypeptidase and aminoacylase-1). This suggests that the protein is involved in the release of free amino acid by hydrolyzing a peptidic bond. As the drought stress progressed, citrulline became one of the major components in the total free amino acids. Eight days after withholding watering, although the lower leaves wilted significantly, the upper leaves still maintained their water status and the content of citrulline reached about 50% in the total free amino acids. The accumulation of citrulline during the drought stress in wild watermelon is an unique phenomenon in C3-plants. These results suggest that the drought tolerance of wild watermelon is related to (1) the maintenance of the water status and (2) a metabolic change to accumulate citrulline.

Amidohydrolases↗

PubMed2000

Osteochondroma of the mandibular body.

We have treated four cases of osseous ostechondromas arising on the mandibular body, where this tumor rarely presents on the craniomaxillofacial bones. There were no recurrences after simple surgical resection of these tumors.

Adult↗

PubMed2000

A new stacking motif: complex alloy structures interpreted as modulated structures.

The structures of lambda-Al4Mn, manganese aluminide, kappa-Al177Cr49Ni, chromium nickel aluminide, and epsilon-Al4Cr, chromium aluminide, which have been described in terms of the aggregation of clusters until now, are interpreted as modulated structures. They are basically composed of close-packed layers with ordered atomic vacancies. The observed stacking motif of the atoms can be found in many phases related to icosahedral and decagonal quasicrystals. This analysis will be helpful in the study of not only many complex alloys, but also quasicrystals.

Alloys↗

PubMed2000

Bartonella henselae infection as a cause of fever of unknown origin.

Fourteen of 41 patients (34%) with a serological diagnosis of Bartonella henselae infection were found to have prolonged fever or fever of unknown origin, suggesting that generalized systemic B. henselae infection is not rare in immunocompetent healthy individuals.

Adolescent↗

PubMed2000

Abdominal helical CT: evaluation of optimal doses of intravenous contrast material--a prospective randomized study.

PURPOSE: To determine the optimal dose of intravenous contrast material for helical computed tomography (CT) of the abdomen on the basis of patient weight. MATERIALS AND METHODS: A prospective randomized study of helical CT of the abdomen was performed by using different doses of intravenous contrast material in 221 patients (mean body weight, 57.3 kg) who were assigned randomly to three groups receiving 1.5, 2.0, or 2.5 mL/kg or a fixed dose of 100 mL of iopamidol 300. The degree of enhancement was scored visually. The CT numbers (HU) of the aorta, portal vein, liver, and pancreas were obtained at three levels of the abdomen. RESULTS: In arterial enhancement, the 2.0 mL/kg, 2.5 mL/kg, and fixed-dose groups were significantly better than the 1.5 mL/kg group, but there was no significant difference among the 2.0 mL/kg, 2.5 mL/kg, or fixed-dose groups. The degree of enhancement of the liver, pancreas, and portal vein increased with larger doses. At visual analysis, hepatic parenchymal enhancement was graded as good or excellent in 64% of the 1.5 mL/kg, 85% of the 2.0 mL/kg, 94% of the 2.5 mL/kg, and 65% of the fixed-dose groups. CONCLUSION: When dose was tailored to patient weight, the use of 2.0-2.5 mL/kg of intravenous contrast material produced better results than did 1.5 mL/kg or a fixed dose. Arterial enhancement did not differ among the 2.0 mL/kg, 2.5 mL/kg, or fixed-dose groups.

Abdominal Neoplasms↗

PubMed2000

[Pharmacological and clinical properties of cetirizine hydrochloride].

A number of reports have characterized cetirizine as a potent histamine H1-receptor antagonist possessing inhibitory effects on eosinophil chemotaxis. In clinical pharmacological tests, cetirizine markedly reduced wheal and flare responses induced by histamines. The inhibition was fast onset, potent and long-lasting. A single clinical dose of cetirizine was more potent in inhibiting wheal response than other antihistamines such as terfenadine, loratadine, epinastine and ebastine. Cetirizine also inhibited eosinophil chemotaxis in vitro at a concentration easily attained after a clinical dose of 10 mg. Eosinophil infiltration into a site challenged with allergen in vivo was also inhibited. Potent antihistaminic effects of cetirizine afforded fast and strong relief from histamine-induced symptoms such as sneezing and rhinorrhoea in allergic rhinitis and itchy sensation in idiopathic chronic urticaria. Inhibitory effect of cetirizine on eosinophil chemotaxis may alleviate minimal persistent inflammation due to faintly but repeated intake of allergen. Such anti-inflammatory properties of cetirizine may be beneficial in reducing hypersensitivity to normalize the upper respiratory tract and eosinophil-related skin inflammation.

Animals↗

PubMed2000

Involvement of nitric oxide from nerves on diarrhea induced by castor oil in rats.

Nitric oxide (NO) is involved in the mechanism of castor oil-induced diarrhea. This study was performed to elucidate the source of NO. Diarrhea was induced by oral administration of castor oil in rats. Diarrhea was significantly inhibited by the pre-treatment with a relatively selective nerve NO synthase inhibitor, 7-nitroindazole. This effect was attenuated by the treatment with L-arginine. Capsaicin-sensitive afferent nerve degeneration did not affect the diarrhea. N(G)-Nitro-L-arginine methylester significantly inhibited diarrhea even in capsaicin-pretreated rats. These data suggest, at least in part, the involvement of NO from nerves on the diarrhea induced by castor oil in rats.

Animals↗

PubMed2000

[A case of Sjögren's syndrome complicated by polymyositis and sarcoidosis with HLA-B7 and DR 8: common causes of susceptibility for these diseases].

We describe a case of a Japanese patient initially presenting with Sjögren's syndrome who later developed polymyositis and sarcoidosis. A 67-year-old woman with a 4 month history of myalgia was admitted in April 1998 for examination. The patient had a 10 year history of symptoms consistent with Sjögren's syndrome. A diagnosis of polymyositis was made based on a biopsy of the muscle and an electromyogram. Positive Shirmer and Rose Bengal tests and results of a minor salivary gland biopsy were all consistent with Sjögren's syndrome. Chest computed tomography detected a bilateral hilar lymphadenopathy. Microscopic examination of a mediastinal lymph node demonstrated multiple noncaseating granulomas with multiple epithelioid cells and Langhans-like giant cells. A diagnosis of sarcoidosis was made based on these findings. Hepatitis C infection was also detected by elevated antibody levels. The patient was given 40 mg/day of oral prednisolone and a remission of her myositis and lymphadenopathy was obtained. The patient exhibited HLA-B7 and HLA-DR 8. HLA-DR 8 is commonly associated with these three disorders, and HLA-B7 is also associated with overlap syndrome in Japanese patients. The present case suggested the possibility of a common etiological background for these three disorders. Furthermore, the importance of genetic background, including HLA phenotype, in determining susceptibility to these disorders was demonstrated.

Aged↗

PubMed2000

[Chronic granulomatous disease accompanying a deep cervical abscess in a young child].

We report the diagnosis and otorhinological treatment of a rare case of cervical abscess in association with chronic granulomatous disease (CGD). A 19-month-old boy was admitted to our hospital's Department of Pediatrics with fever and a swollen neck. Antibiotic treatment (FMOX PIPC, and PAPM) was ineffective, so the patient was referred to our department for otorhinological treatment. A deep cervical abscess was drained using paracentesis in the Outpatient Department, but the condition did not improve. Surgery to drain the cavity was therefore performed. The wound was irrigated with oxydol, and the surgery was a success. Immunodeficiency was suspected, because of the antibiotic treatment's failure. Further examination clarified that the disease was CGD, but this diagnosis was difficult to establish. The result of the NBT test was 120%. However, some examination demonstrated that active oxygen production was impaired. The production of cytochrome b in this patient was confirmed using flow cytometric analysis. Both parents were confirmed to be carriers upon examination. The patient was therefore diagnosed as having CGD as a result of an autosomal recessive inheritance.

Abscess↗

PubMed2000

[Treatment strategy for cervical node metastasis from squamous cell carcinoma of the oropharynx].

The purpose of this study is to ascertain the role of neck surgery and radiation therapy for cervical lymph node metastasis in oropharyngeal cancer patients. We reviewed 217 previously untreated patients with squamous cell carcinoma of the oropharynx who were treated at the Cancer Institute Hospital in Tokyo between 1971 and 1995. The N stage distribution was; N0: 83(38.2%), N1: 42(19.4%), N2a: 23(10.6%), N2b: 27(12.4%), N2c: 33(15.2%), and N3: 9(4.2%). A predominance of cervical node metastases in level II and III was revealed and there were no skip metastases outside of level II and III. The control rate of cervical metastasis for each N stage was; N0: 96.9%, N1: 90.0%, N2a: 76.5%, N2b: 62.5%, N2c: 50.0%, and N3: 0%. Definitive irradiation provided sufficient treatment for small nodes, when the primary tumor growth was well controlled by radiation therapy. Neck dissection was necessary for more advanced neck metastases. Selective limited neck dissection (level II and III) is recommended for N0 and N1 patients, and modified or classical RND is considered to be better for most cases with N2 and N3.

Adult↗

PubMed2000

[Three-dimensional imaging of hepatic and intrahepatic portal veins with helical CT: determination of optimal volume of contrast medium by intravenous injection using MIP technique].

In this study, the optimal volume of contrast medium in the liver for three-dimensional (3D) imaging of the hepatic and portal veins by helical CT were determined by intravenous injection using the MIP technique. In the 48 cases examined, CT images of the liver were obtained following the administration of contrast medium (90, 120, or 150 ml and 1.0 <, < or = 1.5 ml; 1.5 <, < or = 2.0 ml; 2.0 <, < or = 2.5 ml or 2.5 <, < or = 3.0 ml/kg) for determination of the optimal volume. The mean body weight of the patients was 59 kg. Contrast medium (Iopamidol 300 mgl/ml) was injected at a rate of 3 ml/sec, and scanning was initiated 70 sec after the beginning of injection. Images were obtained throughout the entire liver using 5-mm collimation. MIP images were graded from poor to excellent based on their visualization of the hepatic vessels. Images produced with 120 ml of contrast medium presented excellent images of hepatic vessels, superior to those produced with 90 ml (hepatic vein: p < .001, portal vein: p < .001). Images produced with 2.0 <, < or = 2.5 ml/kg of contrast medium presented excellent images of the portal vein, superior to those produced with 1.5 <, < or = 2.0 ml/kg ml (p < 0.05). It is evident from the present data that a contrast medium volume of more than 120 ml or 2.0 <, < or = 2.5 ml/kg is sufficient for three-dimensional imaging of hepatic vessels. These images may be a useful diagnostic tool in patients with hepatic disease.

Contrast Media↗

PubMed2000

[Two cases of acute myelogenous leukemia complicated with fatal gastrointestinal tract bleeding after treatment with idarubicin and cytarabine].

We describe herein two newly diagnosed patients with acute myelogenous leukemia (AML), who were treated twice with an idarubicin hydrochloride (IDR)-containing regimen as a response-orientated induction therapy. Both patients had severe gastrointestinal tract hemorrhage complications at their nadir. The two patients were as follows: a 35-year-old male, FAB-M4, and a 47-year-old female, FAB-M0. They received the same induction chemotherapy (IDR 12 mg/m2 for four days and cytarabine 100 mg/m2 for ten days). No response (NR) was obtained in either, so they underwent the same regimen again. During the period of myelosuppression, they developed severe gastrointestinal hemorrhage. One died of sepsis, and the other of acute respiratory distress syndrome without a recovery in bone marrow. The fetal gastrointestinal tract complications may have been due to severe myelosuppression and mucosal damage in these patients. Careful observation will be needed to prevent such severe complications after the treatment with IDR.

Adult↗

PubMed2000

Oxidative cleavage of the octyl side chain of 1-(3,4-dichlorobenzyl)-5-octylbiguanide (OPB-2045) in rat and dog liver preparations.

The metabolism of 1-(3,4-dichlorobenzyl)-5-octylbiguanide (OPB-2045), a new potent biguanide antiseptic, was investigated using rat and dog liver preparations to elucidate the mechanism of OPB-2045 metabolite formation, in which the octyl side chain is reduced to four, five, or six carbon atoms. Chemical structures of metabolites were characterized by 1H NMR, fast atom bombardment/mass spectrometry, and liquid chromatography/electrospray ionization-tandem mass spectrometry. Three main metabolites were observed during incubation of OPB-2045 with rat liver S9: 2-octanol (M-1), 3-octanol (M-2), and 4-octanol (M-3). In the incubation of OPB-2045 with dog liver S9, eight metabolites were observed, seven of which being M-1, M-2, M-3, 2-octanone (M-4), threo-2,3-octandiol (M-5), erythro-2,3-octandiol (M-6), and 1,2-octandiol (M-7). M-5 and M-6 were further biotransformed to a ketol derivative and C-C bond cleavage metabolite (hexanoic acid derivative), an in vivo end product, in the incubation with dog liver microsomes. The reactions required NADPH as a cofactor and were significantly inhibited by the various inhibitors of cytochrome P450 (i.e., CO, n-octylamine, SKF 525-A, metyrapone, and alpha-naphthoflavone). The results indicate that the degraded products of OPB-2045 are produced by C-C bond cleavage after monohydroxylation, dihydroxylation, and ketol formation at the site of the octyl side chain with possible involvement of cytochrome P450 systems. This aliphatic C-C bond cleavage by sequential oxidative reactions may play an important role in the metabolism of other drugs or endogenous compounds that possess aliphatic chains.

Animals↗

PubMed2000

In vitro characterization of the oxidative cleavage of the octyl side chain of olanexidine, a novel antimicrobial agent, in dog liver microsomes.

The metabolism of olanexidine [1-(3,4-dichlorobenzyl)-5-octylbiguanide], a new potent biguanide antiseptic, was investigated in dog liver microsomes to characterize the enzyme(s) catalyzing the biotransformation of olanexidine to C-C bond cleavage metabolites. Olanexidine was initially biotransformed to monohydroxylated metabolite 2-octanol (DM-215), and DM-215 was subsequently oxidized to diol derivatives threo-2,3-octandiol (DM-221) and erythro-2,3-octandiol (DM-222). Diols were further biotransformed to a ketol derivative and C-C bond cleavage metabolite (DM-210, hexanoic acid derivative), an in vivo end product, in the incubation with dog liver microsomes. The formations of DM-215, DM-221, DM-222, and DM-210 followed Michaelis-Menten kinetics, and Eadie-Hofstee analysis of the metabolite formation activity confirmed single-enzyme Michaelis-Menten kinetics. The K(m) and V(max) values for the formation of DM-210 appeared to be 2.42 microM and 26.6 pmol/min/mg in the oxidation of DM-221 and 2.48 microM and 30.2 pmol/min/mg in the oxidation of DM-222. The intrinsic clearance (V(max)/K(m)) of the C-C bond cleavage reactions was essentially the same with either DM-221 or DM-222 as substrate. These oxidative reactions were significantly inhibited by quinidine, a selective inhibitor of CYP2D subfamilies, indicating the metabolic C-C bond cleavage of the octyl side chain of olanexidine to likely be mediated via the CYP2D subfamily in dog liver microsomes. This aliphatic C-C bond cleavage by cytochrome P450s may play an important role in the metabolism of other drugs or endogenous compounds possessing aliphatic chains.

Animals↗

PubMed1999

Competitive Adsorption of Chloroform and Iron Ion onto Activated Carbon Fiber.

Chloroform in tap water has been a significant problem because it may be a carcinogenic substituent. Iron ion exists in tap water because of dissolution from iron water pipes. Iron ions in tap water cause discoloration and a bad odor. The isotherms of chloroform and iron ion adsorption onto activated carbon fibers in a single solution (chloroform or iron ion) and in a binary mixture solution (chloroform and iron ion) were investigated to estimate the competitiveness between chloroform and iron ions. The amount of adsorbed iron ions increased with increasing pore volume of the activated carbon fibers, while that of chloroform decreased. The amount of chloroform adsorbed onto the activated carbon fibers in the binary mixture solution was greater than that in the single solution. These results indicate that the adsorption of chloroform and iron ion onto activated carbon fibers could be competitive. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

Nitric oxide production is decreased in the brain of the seizure susceptible EL mouse.

To investigate nitric oxide production in the brain of the EL mouse, an inbred mutant strain of the ddY mouse that is susceptible to convulsive seizures, we measured whole brain nitric oxide metabolites, and counted the number of nitric oxide-producing cells in the parietal cortex and striatum. Nitric oxide metabolites in the brain and serum were determined by measuring levels of nitrite plus nitrate. Nitric oxide-producing cells were demonstrated histochemically by staining for nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase. Levels of nitrite plus nitrate in the whole brain were significantly lower than those of the control mice, although levels of nitrite plus nitrate in the serum did not differ between groups. There were significantly fewer NADPH-diaphorase-positive cells in the parietal cortex and striatum of the EL mouse compared to the ddY controls. These results suggest that lower nitric oxide production in the brain may be related to the susceptibility of the EL mouse to convulsive seizures.

Animals↗

PubMed1999

Anti-angiogenic activity of a novel synthetic agent, 9alpha-fluoromedroxyprogesterone acetate.

9Alpha-fluoromedroxyprogesterone acetate (FMPA) is a novel synthetic analog of medroxyprogesterone acetate (MPA), widely used as therapeutic agent for breast and endometrium cancers. FMPA showed almost the same binding affinities to the progesterone and glucocorticoid receptors as MPA. In the rabbit corneal assay, FMPA, MPA and fumagillin significantly inhibited the angiogenic response induced by rat mammary tumor at doses of 0. 1, 1 and 50 microg/pellet, respectively, so FMPA showed greater anti-angiogenic activity than MPA and fumagillin. In the mouse dorsal air sac method, FMPA inhibited the mouse sarcoma 180 cell-induced angiogenesis by oral administration at a dose of 200 mg/kg. FMPA inhibited the activity of plasminogen activator (PA) in bovine endothelial cells. These results suggest that FMPA may be useful for diseases associated with angiogenesis by oral administration.

Angiogenesis Inhibitors↗