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S Ohta

Publications and source records attributed to S Ohta.

At least 37 records · Page 2Linked to original sources
PubMed2004

Oxidation and rearrangements of flavanones by mammalian cytochrome P450.

To clarify the metabolic pathways of flavanones in mammals, the metabolism of (+/-)-flavanone and (+/-)-4'-methoxyflavanone by rat liver microsomes and recombinant human P450s in which structural changes are readily identifiable were examined. The beta-nicotinamide adenine dinucleotide phosphate (NADPH)-dependent formation of flavone plus (+/-)-2,3-trans-flavanonol and of 4'-methoxyflavone plus (+/-)-2,3-trans-4'-methoxyflavanonol, respectively, by rat liver microsomes was observed. The same metabolites were generated by recombinant human P450s in addition to the formation of isoflavone from (+/-)-flavanone. The kinetic isotope effects in these reactions were examined using deuterated (+/-)-flavanone and (+/-)-4'-methoxyflavanone. There was a strong isotope effect in the production of flavanonols, but the isotope effect in the production of flavones was small. The results indicated that the P450-mediated conversion of (+/-)-flavanone and of (+/-)-4'-methoxyflavanone to the corresponding metabolites proceeded via abstraction of a hydrogen radical from the C-2- or C-3-position of the flavanone skeleton. The antioxidant properties of flavanone and its metabolites were examined by measuring superoxide-scavenging activity in a xanthine-xanthine oxidase-cytochrome c system. (+/-)-2,3-trans-Flavanonol had higher activity than that of other flavonoids. Flavanones are metabolized by mammalian P450s, providing important information relevant to the metabolism and pharmacological action of dietary flavanones.

Animals↗
PubMed2004

[Anterior cervical approach for resection of brachial plexus schwannoma expanding into the thoracic apex].

Primary tumors of the brachial plexus are unusual. We describe 2 patients with schwannomas of the brachial plexus that had the radiologic appearance of apical lung masses. We used anterior cervical approach for both of the patients. Our technique permitted safe and complete resection of the tumors of this complex area. Both tumors were arising from the Th1 component of brachial plexus. Histopathological findings revealed that both of the tumors were benign schwannomas. This approach is quick and safe, allowing much better control of the important vascular and neural structures of the thoracic apex. Tumors at the area are inaccessible by using posterolateral thoracotomy or video-assisted thoracic surgery. We suggest that the anterior cervical approach would be applied for the resection of other kind of tumors in the thoracic apex.

Brachial Plexus↗
PubMed2004

[Schwannoma of the recurrent laryngeal nerve; report of a case].

A 57-year-old woman was admitted to our hospital because of an abnormal shadow on her chest X-ray film and a palpable left neck mass. She had a mild cough. Computed tomography (CT) scans and magnetic resonance imaging (MRI) of the chest demonstrated a well-circumscribed, huge mass (approximately 14 cm in diameter) in the left anterior mediastinum. On June 12th, 2000, the mass was resected. During surgery, the tumor seemed to arise from the left recurrent laryngeal nerve. The pathological examination revealed the tumor as a schwannoma. Recurrent laryngeal nerve schwannoma is extremely rare.

Cranial Nerve Neoplasms↗
PubMed2004

[Liposarcoma originating in the neck and the mediastinum after removal of mediastinal lipoma].

A 47-year-old man, who had undergone removal of an upper mediastinal lipoma 9 years previously, was referred to our hospital for swelling of the right neck and wheezing. The chest X-ray showed enlargement of the upper mediastinum. Contrast-enhanced chest computed tomography and magnetic resonance imaging demonstrated a tumor with fatty density extended from the upper mediastinim to the right side of the neck. Two-stage tumor resection was carried out. On gross pathological examination the tumor was soft and fatty. Microscopic examination revealed well differentiated liposarcoma. Postoperative radiation therapy (50 Gy) was carried out. The patient remains free of disease 3 years after radiation therapy.

Head and Neck Neoplasms↗
PubMed2003

A neonatal form of glycogen storage disease type IV.

We report of an infant with neonatal glycogen storage disease type IV (GSD IV) who was examined for severe hypotonia and cardiomyopathy. On the muscle biopsy there were many fibers with diastase-resistant polyglucosan bodies. Glycogen branching enzyme (GBE1) activity in the muscle was markedly reduced. The infant had a homozygous single nucleotide deletion in the open reading frame of GBE1 gene.

1,4-alpha-Glucan Branching Enzyme↗
PubMed2003

PRQFVamide, a novel pentapeptide identified from the CNS and gut of Aplysia.

We have purified a novel pentapeptide from the Aplysia nervous system using bioassay on gut contractions. The structure of the peptide is Pro-Arg-Gln-Phe-Val-amide (PRQFVa). The precursor for PRQFVa was found to code for 33 copies of PRQFVamide and four related pentapeptides. Peaks corresponding to the predicted masses of all five pentapeptides were detected in Aplysia neurons by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Northern analysis revealed that expression of the precursor is abundant in the abdominal ganglion, much less in the pedal and cerebral ganglia, and rarely seen in the buccal and pleural ganglia. PRQFVa-positive neurons, mapped by immunohistochemistry and in situ hybridization, were present in all the central ganglia. PRQFVa immunopositive processes were observed in the gut, particularly in association with the vasculature. Some arteries and other highly vascularized tissues, such as the gill and the kidney, also contain numerous PRQFVa immunopositive processes. Application of synthetic PRQFVa suppresses not only contractions of the gut but also contractions of vasculature. PRQFVa is expressed in some of the neurons within the feeding circuitry and application of synthetic PRQFVa was found to decrease the excitability of some (B4/5 and B31/32) but not all (B8) neurons of the buccal feeding circuit. Our findings suggest that PRQFVa may act as a modulator within the feeding system as well as in other systems of Aplysia.

Amides↗
PubMed2003

Neurotoxicity of an endogenous brain amine, 1-benzyl-1,2,3,4-tetrahydroisoquinoline, in organotypic slice co-culture of mesencephalon and striatum.

Organotypic slice co-culture of the ventromedial portion of the mesencephalon and striatum was used to evaluate the neurotoxicity of 1-benzyl-1,2,3,4-tetrahydroisoquinoline, an endogenous brain amine related to Parkinson's disease. 1-Benzyl-1,2,3,4-tetrahydroisoquinoline is specifically increased in the cerebrospinal fluid of patients with Parkinson's disease and induces parkinsonian features in the monkey and mouse. Here, it decreased the dopamine content of the cultured mesencephalon in both dose- (10-100 microM) and time- (24 h to 7 days) dependent manners. This result suggests that the neurotoxicity of 1-benzyl-1,2,3,4-tetrahydroisoquinoline is correlated with the overall exposure (concentration multiplied by exposure time). Culture with 100 microM 1-benzyl-1,2,3,4-tetrahydroisoquinoline for 24 h irreversibly reduced the dopamine content. Furthermore, culture with 100 microM 1-benzyl-1,2,3,4-tetrahydroisoquinoline for 10 days caused morphological changes, including cell body shrinkage and distortion of dendritic morphology, in tyrosine hydroxylase-positive cells in the mesencephalon and reduced the number of cells by half. The increase in lactate dehydrogenase activity in the media produced by 1-benzyl-1,2,3,4-tetrahydroisoquinoline was significant in culture of the mesencephalon alone or its co-culture with striatum, but not in cultures of other brain regions. We suggest that 1-benzyl-1,2,3,4-tetrahydroisoquinoline is toxic to tyrosine hydroxylase-positive cells in the ventral mesencephalon and that it is correlated with the integral of the concentration by time of exposure. Thus a low concentration of 1-benzyl-1,2,3,4-tetrahydroisoquinoline may first induce a decrease in the dopamine content then shrinkage of the cell body, followed by the slow death of dopaminergic neurons over a long period. This is the first report that indicates 1-benzyl-1,2,3,4-tetrahydroisoquinoline exerts neurotoxicity at the cellular level, and reveals in part the character of its neurotoxicity.

Animals↗
PubMed2003

DeltaFosB, but not FosB, induces delayed apoptosis independent of cell proliferation in the Rat1a embryo cell line.

The fates of Rat1a cells expressing FosB and DeltaFosB as fusion proteins (ER-FosB, ER-DeltaFosB) with the ligand binding domain of human estrogen receptor were examined. The binding of estrogen to the fusion proteins resulted in their nuclear translocation and triggered cell proliferation, and thereafter delayed cell death was observed only in cells expressing ER-DeltaFosB. The proliferation of Rat1a cells, but not cell death triggered by ER-DeltaFosB, was completely abolished by butyrolactone I, an inhibitor of cycline-dependent kinases, and was partly suppressed by antisense oligonucleotides against galectin-1, whose expression is induced after estrogen administration. The cell death was accompanied by the activation of caspase-3 and -9, the fragmentation of the nuclear genome and cytochrome c release from the mitochondria, and was suppressed by zDEVD-fmk and zLEHD-fmk but not zIETD-fmk. The cell death was not suppressed by exogenous His-PTD-Bcl-x(L) at all, suggesting involvement of a Bcl-x(L)-resistant pathway for cytochrome c release.

Animals↗
PubMed2003

Association of polymorphisms in the estrogen receptor alpha gene with body fat distribution.

OBJECTIVE: To examine whether polymorphisms of the estrogen receptor (ER) alpha gene are associated with body fat distribution. DESIGN: Cross-sectional, epidemiological study of two single-nucleotide polymorphisms, a T --> C (PvuII) and an A --> G (XbaI), in the first intron of the ERalpha gene. SUBJECTS: A total of 2238 community-dwelling middle-aged and elderly Japanese population (age: 40-79 y). MEASUREMENTS: The ERalpha genotypes (by automated fluorescent allele-specific DNA primer assay system), anthropometric variables, fat mass (FM) and percentage FM (%FM) (by dual-energy X-ray absorptiometry). RESULTS: FM and waist were inversely associated with age (r=-0.630 and -0.504, respectively) in women with the GG genotype. On the other hand, waist circumference of the AA genotype was positively correlated with age (r=0.231). Thus, for middle-aged women (40-59 y) with the AG or GG genotype body mass index (BMI), %FM, FM, waist, hip and waist-to-hip ratio (WHR) were larger than those with the AA genotype. In particular, FM and waist were greater by 20% and 9%, respectively, for the GG genotype, compared to the AA genotype. Alternatively, FM and waist were smaller by 18% and 6%, respectively, in older women with the GG genotype, compared to the AA genotype. No effect was found among the A --> G polymorphisms for men. For both genders, no difference was found in any variables among the TT, TC and CC genotypes with the exception of BMI of older men (60-79 y). CONCLUSION: No association was found between the ERalpha gene polymorphisms and body fat distribution in men. For women, the A --> G polymorphism, in particular the GG genotype, may contribute to the development of upper-body obesity in middle-aged individuals, but may serve to decrease the whole-body and abdominal fat tissue of older individuals.

Absorptiometry, Photon↗
PubMed2003

MPP+ analogs acting on mitochondria and inducing neuro-degeneration.

This review focuses on the mechanisms of action and the injurious effect of complex I inhibitors, of which 1-methyl-4-phenylpyridinium ion (MPP(+)) is a well studied example. These compounds can be divided into two groups, i.e. competitive inhibitors with respect to ubiquinone, such as piericidine A, and non-competitive inhibitors such as rotenone. Complex I inhibitors such as MPP(+) have been reported to induce anatomical, behavioral, and biochemical changes similar to those seen in Parkinson's disease, which is characterized by nigrostriatal dopaminergic neuro-degeneration. Spectroscopic analyses and structure-activity relationship studies have indicated that the V-shaped structure of the rotenone molecule is critical for binding to the rotenone binding site on complex I. Many isoquinoline derivatives, some of them endogenous, are also complex I inhibitors. Many lines of evidence show that complex I inhibitors elicit neuronal cell death. Recently, it was reported that chronic and systemic exposure to low-dose rotenone reproduces the features of Parkinson's disease. This work further focused attention on compounds acting on mitochondria, such as MPP(+). In Guadeloupe, the French West Indies, patients with atypical parkinsonism or progressive supranuclear palsy are frequently encountered. These diseases seem to be associated with ingestion of tropical herbal teas or tropical fruits of the Annonaceae family, which contain complex I inhibitors such as benzylisoquinoline derivatives and acetogenins. Complex I inhibitors may not simply result in reactive oxygen species generation or ATP exhaustion, but may influence complex downstream signal transduction processes. An understanding of these changes would throw light on the ways in which complex I inhibitors induce a wide range of abnormalities.

1-Methyl-4-phenylpyridinium↗
PubMed2003

[Resected cases with primary lung cancer after preoperative high dose irradiation].

After greater than 60 gray (Gy) irradiation, we performed the pulmonary resection in the 18 primary lung cancer cases. The mean irradiation dose to the tumor was 68.2 (range 60-101) Gy, and the mean irradiation dose to the bronchial stump was 47.1 (range 0-82) Gy. Median time from end of irradiation to surgical resection was 136 (range 20-894) days. One partial resection, 9 single lobectomies, 3 double lobectomies, and 5 pneumonectomies were done. Mainly, we closed the bronchial stump by the automatic stapling device and additional hand suturing. The bronchial stump was covered in the 12 cases by the owner stalk thymus, the intercostals muscular flap, the omentum flap, and et al. The major postoperative complications due to preoperative irradiation were not seen. Bronchopleural fistulas did not occur. Pathologically, the wall of the submucosal capillary vessels were getting thick in the patients operated more than 3 months later after irradiation. In such cases with the decrease of the blood flow, the bronchial stump should be covered. The pulmonary resection after the high dose irradiation was considered to be tolerable.

Adult↗
PubMed2003

Developmental biology meets with reproductive engineering; interdisciplinary science area as a breakthrough.

It has been postulated many times that different scientific topics and strategies often encounter each other, which create cutting edge research field resulting in further significant progresses of science. This was also a lesson bestowed by Prof. Raymond Wegmann where he created innovative research field for biology, molecular biology and biochemistry-biophysics. Progresses of developmental biology were boosted by molecular biology and reproductive engineering where ES cells and embryonic manipulation are necessary. There are no questions about the utility of their technologies. Reviews on their contributions with respect to the condition of genome manipulation are addressed.

Animals↗