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Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 109 records · Page 6Linked to original sources
PubMed2000

Fullerenes separation with monomeric type C30 stationary phase in high-performance liquid chromatography.

The temperature effect on the separation of fullerenes in LC was examined using monomeric type C30, C18 and C8 alkyl bonded stationary phases. It appears that the C30 phase exhibits superior separation ability for fullerenes. It is observed that the maximum retention temperature of fullerenes on the C30 phase is around 20 degrees C. A strong correlation between the changes in NMR spectra and the retention behavior of the solutes was found. The interpretation of the retention behavior of fullerenes on the alkyl bonded stationary phases, including the behavior in subambient temperature, is discussed using the information obtained by CP-MAS solid-state NMR spectroscopy and LC.

Carbon↗
PubMed2000

A new method for histamine release from purified peripheral blood basophils using monoclonal antibody-coated magnetic beads.

A new method for evaluating histamine release from purified basophils was developed. Basophil-containing leukocytes were directly purified from a small amount of peripheral blood using monoclonal antibody BA312-coated magnetic beads. The purified basophils still rosetted to magnetic beads maintained a normal response to anti-IgE and to dust mite allergen in comparison with the conventional method using washed leukocytes. This methodology facilitates the purification of basophils, anti-IgE- and allergen-induced histamine release, and subsequent histamine determination within only 3 h. The released histamine was analyzed by an enzyme-linked immunosorbent assay (ELISA) with a characteristic detection profile. Since all steps were performed in 96-well microplates, many clinical samples could be analyzed at the same time, permitting easy applications in routine laboratories.

Antibodies, Monoclonal↗
PubMed2000

Identification and light-induced expression of a novel gene of NADPH-protochlorophyllide oxidoreductase isoform in Arabidopsis thaliana.

In Arabidopsis thaliana, we identified a novel gene of a NADPH-protochlorophyllide oxidoreductase (POR) isoform, which catalyzes the light-dependent protochlorophyllide a reduction in the chlorophyll (Chl) biosynthetic pathway. The deduced amino acid sequence of the novel POR isoform (PORC) showed significant identities ( approximately 75%) with the previously isolated two POR isoforms of A. thaliana. Contrasting with these POR isoforms, the PORC transcript increased in etiolated seedlings by illumination, and was dominantly expressed in immature and mature tissues. The present results demonstrated that Chl biosynthesis and chloroplast biogenesis in A. thaliana are controlled by three POR isoforms, which are differentially controlled by light and development.

Amino Acid Sequence↗
PubMed2000

Sphingosine 1-phosphate stimulates proliferation and migration of human endothelial cells possibly through the lipid receptors, Edg-1 and Edg-3.

Sphingosine 1-phosphate (S1P) stimulates thymidine incorporation (DNA synthesis), cell growth and cell migration in human aortic endothelial cells (HAECs). The extent of the S1P-induced responses are comparable to those stimulated by vascular endothelial growth factor, one of the most potent stimulators of angiogenesis. These responses to S1P were mimicked by dihydrosphingosine 1-phosphate, an S1P receptor agonist, and inhibited by pertussis toxin (PTX), an inactivator of G(i)/G(o)-proteins. S1P also induced activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38 MAP kinase). The activation of these enzymes was inhibited again by PTX and also by suramin, a non-selective receptor antagonist. S1P-induced DNA synthesis and ERK activation were inhibited by PD98059, an ERK kinase inhibitor, but not by SB203580, a p38 MAP kinase inhibitor. In contrast, cell migration and p38 MAP kinase activation, in response to S1P, were inhibited by SB203580 but not by PD98059. In HAECs, high-affinity S1P binding activity and expression of Edg-1 and Edg-3 mRNA were detected. These results suggest that S1P might be a novel angiogenesis factor and that the lipid-induced proliferation and migration of endothelial cells are possibly mediated through cell-surface S1P receptors, Edg-1 and Edg-3, which are linked to signalling pathways.

Antineoplastic Agents↗
PubMed2000

Edg-6 as a putative sphingosine 1-phosphate receptor coupling to Ca(2+) signaling pathway.

The endothelial differentiation gene-6 (Edg-6) was recently identified as an orphan G-protein-coupled receptor. Its predicted amino acid sequence is very close to Edg family of receptor proteins whose ligand is supposed to be lysophosphatidic acid (LPA) or lysosphingolipid such as sphingosine 1-phosphate (S1P) and sphingosylphosphorylcholine (SPC). Transfection of the Edg-6 into Chinese hamster ovary (CHO) cells and K562 cells resulted in the appearance of high-affinity [(3)H]S1P binding activity. Among lipids employed, S1P and, even though less potent, SPC, displaced the [(3)H]S1P binding, but LPA was inactive. In Edg-6-transfected CHO cells, an increase in cytosolic Ca(2+) concentration in response to S1P or SPC was clearly enhanced without change in the LPA-induced action as compared with the vector-transfected cells. The enhancement of the Ca(2+) response was associated with a significant accumulation of inositol phosphate, reflecting activation of phospholipase C. Similar enhancement of Ca(2+) response to S1P or SPC was also observed in Edg-6-expressing K562 cells. These lipid-induced actions in CHO cells and K562 cells expressing Edg-6 were markedly suppressed by pertussis toxin treatment. We conclude that Edg-6 is one of S1P or lysosphingolipid receptors that couple to phospholipase C-Ca(2+) system through pertussis toxin-sensitive G-proteins.

Animals↗
PubMed2000

A potent and highly selective nonpeptidyl nociceptin/orphanin FQ receptor (ORL1) antagonist: J-113397.

We discovered a potent nociceptin/orphanin FQ receptor (ORL1) receptor antagonist, J-113397 (1-[(3R, 4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl-1, 3-dihydro-2H-benzimidazol-2-one). J-113397 inhibited [125I][Tyr(14)]nociceptin binding to Chinese hamster ovary (CHO) cells expressing ORL1 receptor in a dose-dependent manner (IC(50); 2. 3 nM), but showed 600-fold or less affinity for mu-, delta- and kappa-opioid receptors. Nociceptin/orphanin FQ-induced suppression of cyclic AMP accumulation elicited by forskolin was completely inhibited by J-113397 with an IC(50) value of 26 nM. These results indicate that J-113397 is a potent and selective nonpeptidyl antagonist of the ORL1 receptor.

Animals↗
PubMed2000

Access to Wieland-Miescher ketone in an enantiomerically pure form by a kinetic resolution with yeast-mediated reduction.

Both enantiomers of Wieland-Miescher ketone [3,4,8, 8a-tetrahydro-8a-methyl-1,6(2H,7H)-naphthalenedione], in a highly enantiomerically enriched form, became readily available by a newly developed kinetic resolution with yeast-mediated reduction. From a screening of yeast strains, Torulaspora delbrueckii IFO 10921 was selected. The collected cells of this strain, obtained by an incubation in a glucose medium, smoothly reduced only the isolated carbonyl group of the (S)-enantiomer, while the (R)-enantiomer remained intact. Starting from both enantiomers ( approximately 70% ee) prepared by an established proline-mediated asymmetric Robinson annulation, the reduction with T. delbrueckii gave the (R)-enantiomer (98% ee) and the corresponding alcohol (4aS,5S)-4,4a, 5,6,7,8-hexahydro-5-hydroxy-4a-methyl-2(3H)-naphthalenone (94% ee, 94% de) in preparative scale in nearly quantitative yields. An approach for the asymmetric synthesis of the Wieland-Miescher ketone was also successful. 2-Methyl-2-(3-oxobutyl)-1,3-cyclohexanedione, the prochiral precursor, was reduced with this strain to give a cyclic acetal form of (2S, 3S)-3-hydroxy-2-methyl-2-(3-oxobutyl)cyclohexanone, in a stereomerically pure form.

Ketones↗
PubMed2000

Lateral ligament: its anatomy and clinical importance.

Since Miles proposed abdominoperineal excision as a radical surgery for rectal cancer in 1908, surgeons have recognized the lateral ligament in the pararectal space of their patients and attached clinical importance to it, although anatomists did not describe any such configuration in cadavers. By analyzing an experience of 421 lower rectal cancer cases at the Cancer Institute Hospital in Tokyo, discussion of the lateral ligament was focused on its relationship to the fascial arrangements in the pelvis, the pelvic autonomic nervous system, and the lymphatic drainage of the rectum. The lateral ligament is not an anatomical term, but a clinical or surgical one. It exists in a living pelvis as a condensation of connective tissue around the middle rectal artery and is divided into two segments by the inferior hypogastric nerve plexus inside it and the visceral endopelvic fascia around it. The lateral ligament is a pathway of blood vessels and nerve fibers toward the rectum and lymphatic vessels from the lower rectum toward the iliac lymph nodes. Therefore, the lateral ligament plays a critical role in surgery for lower rectal cancer in two respects: the anatomic extent of resection for curing rectal cancer, and the preservation of sexual function.

Collateral Ligaments↗
PubMed2000

Increased adrenomedullin in cerebrospinal fluid after traumatic brain injury in children: a preliminary report.

Adrenomedullin is a recently discovered 52-amino-acid peptide that is a potent vasodilator. Infusion of adrenomedullin increases regional cerebral blood flow and reduces infarct volume after vascular occlusion in rats. Adrenomedullin may represent an endogenous neuroprotectant since it is increased after focal brain ischemia. Cerebral hypoperfusion is present after traumatic brain injury (TBI) in children. We hypothesized that adrenomedullin levels would be increased in children with severe TBI. Total adrenomedullin concentrations were measured using a radioimmunometric assay. Thirty-six samples of ventricular cerebrospinal fluid (CSF) from 10 pediatric patients were collected during the first 10 days after severe TBI (GCS < 8). Control CSF was obtained from 5 children undergoing lumbar puncture, who had normal CSF parameters and no evidence of central nervous system infection. Patients underwent standard neuro-intensive care, including cerebrospinal fluid drainage. Data were analyzed using a univariate regression model. Adrenomedullin concentration was markedly elevated in CSF of children following TBI versus control (mean level 10.65 vs 1.51 fmol/ml, p = 0.006). All 36 case samples had an adrenomedullin concentration above the median value for the controls (1.52 fmol/ml). We conclude adrenomedullin is elevated in the CSF of children following severe TBI. We speculate that it participates in the endogenous response to cerebral hypoperfusion after TBI.

Adrenomedullin↗
PubMed2000

A Stump of Occluded Posterior Cerebral Artery Mimicking a Ruptured Aneurysm: Case Report.

We report on a 63-year-old female with subarachnoid hemorrhage who had a stump of occluded posterior cerebral artery (PCA) mimicking a ruptured aneurysm of the basilar bifurcation. Intraoperatively, the aneurysmal opacification on preoperative angiograms proved to be the residual lumen of the occluded right P1 segment. Because of the nodular appearance and upward direction of the stump of the right P1 segment, it was misinterpreted as an aneurysm. During operation, a tiny ruptured aneurysm missed on preoperative angiograms was found in the left A1-A2 junction and was clipped safely.

Journal Article↗
PubMed2000

Lateral node dissection and total mesorectal excision for rectal cancer.

PURPOSE: Although the existence of lateral lymphatic drainage of the rectum has been verified anatomically, the clinical importance of it has not yet been fully investigated. The lack of a definition of lateral lymphatic flow makes it difficult to analyze and compare data. The aim of this study was to define the concept of lateral lymphatic drainage and explore its relationship to total mesorectal excision and to disclose the incidence and efficacy of dissection of lateral node involvement. METHODS: Review of anatomic and clinical research on lateral lymphatic flow was made to create a definition of lateral lymphatic flow. Based on this review, a three-space dissection was designed and applied. A retrospective analysis was made of 764 patients with rectal cancer treated by a curative three-space dissection operation during 20 years starting in 1975 at Cancer Institute Hospital. RESULTS: Lateral lymphatic flow passes from the lower rectum and through the lateral ligament laterally beyond the mesorectum. It then ascends along the internal iliac artery and, in addition, inside the obturator space. Sixty-six cases proved to have lateral node involvement, which comprised 8.6 percent of all rectal cancer and 16.4 percent of low-lying (lower margin below 5 cm above the dentate line) rectal cancer cases. The five-year survival rate of these 66 cases was 42.4 percent. There were 16 cases that had a solo lateral node involvement. CONCLUSION: Lateral lymphatic flow from low-lying rectal cancer passes outside the boundaries of total mesorectal excision but within the range of curative surgery by three-space dissection.

Humans↗
PubMed2000

A case of malignant lymphoma of the hand.

Malignant lymphoma is rarely seen in the hand. We present a case of malignant lymphoma of the hand with Ga-67 citrate and MR images, and discuss the usefulness of Ga-67 citrate scintigraphy for diagnosing this condition.

Aged↗
PubMed2000

N-glycosylation contributes to the limited cross-reactivity between hemagglutinin neuraminidase proteins of human parainfluenza virus type 4A and 4B.

cDNAs encoding human parainfluenza virus type 4B (hPIV-4B) hemagglutinin neuraminidase (HN) protein were cloned and the nucleotide sequences were determined. A high degree of identity (81.4%) was observed between the nucleotide sequences of hPIV-4A and -4B HN proteins, and an 87.3% identity was found between the deduced amino acid sequences. This degree of identity is considered to be greater than immunological similarity between hPIV-4A and -4B HN proteins determined using monoclonal antibodies. To elucidate the causes of the antigenic difference between HN proteins of hPIV-4A and -4B, we constructed three cDNAs of hPIV-4B HN whose potential N-glycosylation sites were partially or completely the same as in hPIV-4A HN cDNA. We compared the antigenicity of the expressed wild-type and mutant proteins, and found that the antigenicities of the mutant hPIV-4B HN proteins were more similar to the hPIV-4A HN protein than to the non-mutant hPIV-4B HN protein. This study indicated that the antigenic diversity between hPIV-4A and -4B was partly caused by deletion or creation of glycosylation sites, showing that the point mutations resulting in deletion or creation of glycosylation sites is one of the initial steps leading to the division of virus into subtypes.

Amino Acid Sequence↗
PubMed2000

Directed deletions in the aflatoxin biosynthesis gene homolog cluster of Aspergillus oryzae.

To investigate the structure of the aflatoxin gene cluster in Aspergillus oryzae, 39 strains belonging to this species were examined for the existence of pksA, fas1A, aflR and vbs, and the results compared with those for ver-1 obtained previously. These five genes are involved in aflatoxin biosynthesis in Aspergillus parasiticus. The strains examined were categorized into three groups; group 1, having the five homologs; 2, having ver-1 and vbs; and 3, having vbs homologs. Long-PCR analysis of the regions between the five homologs in A. oryzae IFO 4135, coupled with Southern-hybridization analysis, shows that those homologs are clustered with the same arrangement as in A. parasiticus. These results suggest that directed deletions of the cluster occur in A. oryzae strains. The possible breakpoints of the deletions in the strains of group 2 and 3 were estimated.

Aflatoxins↗
PubMed2000

Hepatic parenchymal transection using ultrasonic coagulating shears: a preliminary report.

Ultrasonically activated coagulating shears (CS) can coagulate and divide blood vessels of up to medium size by a tissue-welding technique. We present an application of CS in hepatic parenchymal transection during liver surgery. Intrahepatic vessels are uncovered by the so-called forceps fracture method, and they are coagulated and divided by CS. Larger vessels are tied only on the preserving side before the application of CS. Although further refinement of the CS tip is needed, this method has the potential to significantly simplify and improve surgical procedures for hepatic parenchymal transection.

Adult↗
PubMed2000

Multiple inflammatory pseudotumors mimicking liver metastasis from colon cancer: report of a case.

A 54-year-old man underwent an operation for colon cancer histologically diagnosed as moderately differentiated adenocarcinoma with clinical staging of Dukes C. He was prescribed carmofur for adjuvant chemotherapy. A follow-up computed tomography scan done 6 months later revealed two new low-density areas in the liver. A diagnosis of metastatic adenocarcinoma from the previous colon cancer was presumed, based on the patient's history and radiological findings, and resection of the affected area of liver was performed. Histological examination of these tumors revealed that they were inflammatory pseudotumors (IPT). The patient had an excellent postoperative course and has shown no further signs of recurrence in the 3 years since his last operation. IPT of the liver is a rare disease, for which no methods of diagnosis and treatment have been established, since it is difficult to distinguish IPT from hepatocellular carcinoma or metastatic carcinoma. We describe this case with a review of the 101 cases of IPT documented in the Japanese literature, in the hope that it will contribute to the diagnosis and treatment of this unusual disease entity.

Adenocarcinoma↗
PubMed2000

Long-term follow-up of vitamin B(6)-responsive West syndrome.

We performed a clinical and electroencephalographic follow-up study on 25 patients with West syndrome that was responsive to vitamin B(6) (eight cryptogenic patients and 17 symptomatic patients) who were older than 3 years at the last follow-up. All cryptogenic patients and 13 symptomatic patients were seizure free at the last follow-up. All cryptogenic patients and seven symptomatic patients had intelligent quotient or developmental quotient scores of 75 or higher. The recurrence of clinical seizures was always associated with increases in epileptic discharges. We could successfully discontinue pyridoxal phosphate administration in four cryptogenic and four symptomatic patients who were 1 year, 8 months to 24 years old.

Administration, Oral↗