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Biomedical subjects

T Iwata

Publications and source records attributed to T Iwata.

At least 127 records · Page 7Linked to original sources
PubMed1998

Characterization of the mouse aldose reductase gene and promoter in a lens epithelial cell line.

PURPOSE: To clone and characterize the mouse aldose reductase (AR) gene and evaluate the functional promoter under basal and hypertonic conditions in mouse lens epithelial cells. METHODS: The mouse AR gene structure was determined by DNA sequencing, and its chromosomal localization was determined by fluorescent in situ hybridization. A luciferase reporter gene was utilized to assess promoter activities of mouse, rat, and human AR deletion constructs as well as mouse site-directed mutants containing specific deletions of an aldose reductase enhancer element (AEE) or a tonicity response element (TonE). Electrophoretic mobility shift assays were performed to evaluate binding of trans-acting factors to mouse AEE and TonE. RESULTS: The mouse AR gene (14.2 Kb) is located on chromosome 6. The basal AR promoter activity was greatest for the rat followed by mouse and human. All 3 species demonstrated increased promoter activity under hypertonic conditions. Deletion of TonE decreased mouse AR basal activity 2.5-fold and substantially reduced the osmotic response. Deletion of AEE had only a slight effect on AR promoter activity. Nevertheless, AEE strongly bound multiple trans-acting factors under nonstressed and stressed conditions, while weaker binding was evident for TonE. CONCLUSIONS: Species-specific differences in AR promoter activities suggest the presence of unique regulatory cis-acting elements. The effects of AEE or TonE on AR transcription appear to involve complex transcriptional regulatory mechanisms.

Aldehyde Reductase↗
PubMed1998

Deficient expression of Bruton's tyrosine kinase in monocytes from X-linked agammaglobulinemia as evaluated by a flow cytometric analysis and its clinical application to carrier detection.

The B-cell defect in X-linked agammaglobulinemia (XLA) is caused by mutations in the gene for Bruton's tyrosine kinase (BTK). Using the anti-BTK monoclonal antibody (48-2H), a flow cytometric analysis of intracytoplasmic BTK protein expressed in monocytes was successfully performed. To examine the possible identification of XLA patients and female carriers by this assay, we studied 41 unrelated XLA families with (35) or without (6) known BTK mutations. A flow cytometric assay showed deficient expression of the BTK protein in 40 of 41 patients, complete BTK deficiency in 35, and partial BTK deficiency in 5. One patient exhibited a normal level of BTK expression. All 6 patients with partial BTK deficiency or normal BTK expression had missense BTK mutations. The cellular mosaicism of BTK expression in monocytes from obligate carriers was clearly shown in 35 of 41 families. The results suggested that most BTK mutations in XLA might result in deficient expression of the BTK protein. We conclude that deficient expression of BTK protein can be evaluated by a flow cytometric assay, and the clinical usefulness and limitations in diagnosis of XLA patients and carriers are discussed.

Adolescent↗
PubMed1998

Langerhans cell histiocytosis localized to the eyelid.

We treated a 46-year-old Japanese man with Langerhans cell histiocytosis (LCH) localized to the eyelid alone. He was cured successfully by local and complete resection. Results of pathological examinations of the excised tumor demonstrated diffuse infiltration by atypical histiocytic cells with eosinophilic cytoplasm and convoluted nuclei, S100 immunoreactivity, and tennis-racket-shaped Birbeck granules. Based on these pathological findings, we diagnosed LCH. Clinical examination revealed no LCH involvement in other parts of the body. To our knowledge, there has been only one report of LCH occurring as an isolated tumor in the eyelid. Generally LCH has been reported in children or young people. This is an unusual case of LCH isolated to the eyelid of an older patient.

Eyelid Diseases↗
PubMed1998

The adsorption of substrate-binding domain of PHB depolymerases to the surface of poly(3-hydroxybutyric acid).

The binding characteristic of PHB depolymerase has been studied by using glutathione S-transferase (GST) fusion proteins with substrate-binding domain of three bacterial PHB depolymerases, Alcaligenes faecalis, Comamonas acidovorans and Comamonas testosteroni. Analysis using immuno-gold labeling technique and transmission electron microscopy indicated that a novel GST fusion protein derived from A. Faecalis enzyme adsorbed to the surface of poly(3-hydroxybutyric acid) (P(3HB)) single crystals like other fusion proteins. Comparison of inhibiting degree of P(3HB) powder hydrolysis activity of PHB depolymerase by fusion proteins indicated that three fusion proteins bind to P(3HB) powder in the same degree. The measurement of the surface hydrophobicity of proteins suggests that the interaction of the substrate-binding domain with insoluble P(3HB) may include not only a hydrophobic effect but also molecule-specific contacts.

Acyltransferases↗
PubMed1998

Effect of omental lipid fraction on enhancement of skin flap survival.

The effect of an omental lipid fraction on the rate of skin flap survival in the back of the rat was assessed by planimetric and histological examination. Compared with the control group, those rats treated with the omental lipid fraction showed significant improvement of the flap survival area. On histological examination, the flap instilled with the omental lipid fraction showed vasodilatation and neovascularization between the flap and the bed. A topical application of the omental lipid fraction enhanced the skin flap survival area, and showed vasodilatation in the flap and neovascularization between the skin flap and the recipient bed.

Animals↗
PubMed1998

An immunohistochemical study of amyloid P component, apolipoprotein E and ubiquitin in human and murine amyloidoses.

Amyloid P component (AP) and apolipoprotein E (Apo E), which are known to be minor constituents of amyloid deposits, commonly are associated with almost all types of amyloid deposits. In this study, the distribution of AP-, Apo E- and ubiquitin (Ub)-immunoreactivity (IR) in amyloid deposits in the liver and spleen of human systemic amyloidosis (34 autopsy cases: 17 immunoglobulin light chain derived, 17 amyloid A protein derived) and experimental murine amyloidosis is examined using an immuno-histochemical technique. In human cases, all of the amyloid deposits examined showed colocalization of AP- and Apo E-IR with individual amyloid proteins. In experimental amyloidosis, AP-IR of amyloid deposits in the liver and spleen and Apo E-IR in the liver were seen uniformly throughout this experiment. In contrast, Apo E-IR in the spleen was not uniform at the phase of amyloid deposition. At 4 weeks and at 16 weeks after casein injection, Apo E-IR was unevenly distributed in amyloid deposits in the perifollicular area; however, from 6 to 12 weeks it was seen to be uniform. Ubiquitin-IR of amyloid deposits in human cases was seen in 22 of 34 livers and in 22 of 33 spleens. In experimental amyloidosis, Ub-IR of amyloid deposits was demonstrated in the space of Disse in all mice examined, and there appeared to be a gradual increase in intensity with the amount of amyloid deposition. However, in the spleen, amyloid deposits did not react with anti-Ub antibody in any phase of amyloid induction. These results suggest that Apo E and Ub are not always associated with the process of amyloid deposition and may appear in a deposit after the deposition.

Adult↗
PubMed1998

Structure and chromosome mapping of the human small maf-genes MAFG and MAFK.

The newly emerged Maf family proteins possess a highly conserved basic leucine zipper (bZip) domain in common and are subdivided into large and small Maf proteins. The Maf family proteins appear to regulate cell differentiation processes and also cellular functions as partner molecules of CNC family proteins. To facilitate understanding of the function of small Maf proteins, we isolated the genes (MAFG and MAFK) encoding human small Maf proteins MafG and MafK and characterized their structures and organization by means of restriction enzyme mapping, Southern blot hybridization and nucleotide sequence analysis. Organization of the small maf genes are highly conserved in vertebrates, suggesting an important functional contribution of the gene products. We also examined the location of these genes within the human genome by fluorescence in situ hybridization (FISH) analysis. Human MAFG and MAFK are located at 17q25 and 7p22, respectively. Thus, small maf genes are not clustered in a single locus.

Chromosome Mapping↗
PubMed1998

Paroxysmal atrial fibrillation as a cause of potentially lethal ventricular arrhythmia with myocardial ischemia in hypertrophic cardiomyopathy--a case report.

The mechanism(s) of myocardial ischemia in hypertrophic cardiomyopathy remain unclear. In this report, the authors present a 75-year-old Japanese woman with nonobstructive hypertrophic cardiomyopathy in whom paroxysmal atrial fibrillation caused severe myocardial ischemia and induced sustained ventricular tachycardia. Her coronary angiogram showed normal findings, and no ischemic changes were provoked by either physical exercise testing or dobutamine stress echocardiography under sinus rhythm. In view of these findings, the rapid ventricular response in the absence of atrial contraction may aggravate or induce myocardial ischemia and predispose patients with hypertrophic cardiomyopathy to develop lethal ventricular arrhythmia.

Aged↗
PubMed1998

Urinary excretion of D-serine in human: comparison of different ages and species.

The urinary excretion of D-serine (D-Ser) in human, rat and dog of various ages was studied. Great amounts of D-Ser were consistently excreted in human urine throughout life. No age-dependent changes were observed in urinary D-Ser/total-Ser ratios from the newborn to the aged. D-Ser/creatinine ratios in adult human urine were found to be relatively constant in individuals. The constant excretion of D-Ser in human urine was confirmed by analyzing the consecutive 24 h urine of three volunteers. High concentrations of D-Ser and D-alanine (D-Ala) were found in adult dog urine. The urinary D-Ser concentration was high in young rats at unweaned and weaned periods, and then declined with increasing age. In contrast, the urinary D-Ala concentration was very low in suckling rats, and increased rapidly after the weaned state and then declined with increasing age. The species- and age-related excretion of D-Ser in mammalian urine is considered to be due to the differences in the renal handing of D-Ser, because plasma D-Ser concentrations among the groups were not so different. Although free D-Ser has been detected in animal foods and human colostrum, the amount is insufficient to explain the concentration of D-Ser found in urine. These results indicate that urinary D-Ser in mammals may be mainly of endogenous origin.

Adult↗
PubMed1998

An early systolic sound associated with midventricular obstruction in a patient with hypertrophic cardiomyopathy.

A 57-year-old woman was admitted for examination because of chest discomfort. Transthoracic echocardiography was performed and she was diagnosed as having hypertrophic cardiomyopathy. An echocardiogram also revealed that she had midventricular obstruction with a pressure gradient of 125 mmHg determined by Doppler echocardiography. A phonocardiogram showed an early systolic sound and the beginning of the sound coincided with the time of septal-posterior wall contact. In addition, the timing also corresponded to the sudden obstruction of blood flow in the region of the midventricular narrowing. Furthermore, this sound markedly decreased with the reduction in pressure gradient caused by cibenzoline treatment. Thus, it was concluded that the early systolic sound was associated with midventricular obstruction and produced by a rapid deceleration of the interventricular flow caused by midventricular obstruction.

Anti-Arrhythmia Agents↗
PubMed1998

Epidural hematoma of the clivus. Case report.

This 8-year-old boy presented with a rare case of epidural hematoma of the clivus and atlantoaxial dislocation caused by a hyperflexion injury sustained in a traffic accident. Magnetic resonance (MR) imaging demonstrated an epidural hematoma in the posterior fossa that compressed the pons and medulla. On admission, the patient was confused and had bilateral abducens palsy. He was treated conservatively, and 6 months after admission, the epidural hematoma on the clivus had disappeared on MR imaging and the bilateral abducens palsy was cured. Only two such cases have been reported in the literature. In this report, the authors discuss the mechanism of hematoma formation in this region of the brain.

Abducens Nerve↗
PubMed1998

[High uptake on 11C methionine PET scan in the pituitary gland of a patient with cerebral glioma after surgical abortion].

Positron emission tomography (PET) with various tracers provides physiologic and biochemical information of living organs. Since radiologic examinations are usually avoided in pregnant women, mainly because of the radiation risk to the fetus, little is known about the effect of pregnancy on cerebral blood flow and metabolism. This paper reports findings of a 11C methionine PET scan of the pituitary gland in a woman after an abortion. The patient was a 31-year-old woman who suffered a seizure in the 9th week of her second pregnancy. On admission, computed tomography showed an abnormal mass lesion in the right frontal lobe, and a brain tumor was suspected. The patient and her family asked that that pregnancy be terminated. Seven days after a surgical abortion, methionine PET was performed. The scan showed high methionine uptake in the pituitary gland as well as in the right frontal lobe tumor. We suspected that another tumor was present in the pituitary gland. The right frontal tumor was partially resected, and pathologic examination of the resected specimen showed an astrocytoma (grade 2). After the operation, the patient received 50 Gy irradiation and chemotherapy. Two months after the operation, we performed a second methionine PET scan, which showed high uptake in the residual right frontal tumor but not in the pituitary gland. Results of other radiologic studies of the pituitary gland were normal. These findings suggest that the transport of 11C methionine into the pituitary gland may increase during pregnancy. Moreover, the pituitary gland of pregnancy should be a part of the differential diagnosis of pituitary adenomas in PET scanning. The change in physiologic uptake by the female pituitary gland should be taken into account in the diagnosis of pituitary adenoma with methionine PET.

Abortion, Therapeutic↗
PubMed1998

Examination of prognostic factors after resection of pulmonary metastasis of osteosarcoma by multivariate analysis.

Prognostic factors for the case of pulmonary metastasis of osteosarcoma was examined using the multivariate analysis. 1) The 3-year survival rate after operation of primary focus in 23 cases was 34.8% and the 5-year survival rate was 30.4%. The 3-year survival rate after the first operation of pulmonary metastasis was 30.4% and the 5-year survival rate was 12.2%. No deaths attributed to operation were found. 2) Gender, age, histological type, solitary or multiple pulmonary metastasis, laterality, number of pulmonary metastatic tumors, TDT and DFI were examined, and the laterality, number of pulmonary metastatic tumors and DFI were considered to be useful prognostic factors. DFI among them was most closely associated with postoperative survival days. 3) A significant difference in the number of excised nodules was found between the DFI less than 90 days group and the DFI not less than 90 days group, and the number in the former group was significantly larger. 4) It was suggested that postoperative observation and close examination for pulmonary metastasis at about 3 months intervals after of primary focus are important, and also, positive or negative pulmonary metastasis as the time of examination, particularly, the number metastatic nodules of less than 5 or not less than 5, are reflected in the prognosis. 5) Expected survival time after the first operation pulmonary metastasis appeared possible to estimate as 3.0 x DFI days.

Adolescent↗
PubMed1998

A case of pulmonary metastases of synovial sarcoma surviving for a long period after active surgery.

The patient was a 24-year-old woman. She underwent marginal excision of synovial sarcoma originating in the right femoral soft tissue at the age of 18, followed by local radiation therapy and chemotherapy. At the age of 20, abnormal shadow was indicated in bilateral lungs on plain roentgenography of the chest, and she underwent open-chest surgery for excision of bilateral pulmonary metastatic tumors. She was subjected to bilateral thoracotony repeatedly thereafter for a total of 5 times, and all of the metastatic foci detected in each operation were resected. Consequently, she has been surviving for a long period of about 7 years. The therapeutic outcome of tumor of bone soft tissue is greatly affected by its pulmonary metastasis. Although the therapeutic outcome has recently been improved by large dose chemotherapy and active excision of metastatic foci in the lung, survival time in the case of synovial sarcoma, giant cell sarcoma and Ewing's sarcoma is not very long yet. In the present study, we observed a patient who had lung metastasis of synovial sarcoma of which prognosis is generally considered poor has been surviving for a long time of 7 years owing to active excision of pulmonary metastatic foci. The relation of the present prognostic factors to those in the past were compared.

Adult↗
PubMed1997

Identification of a novel cis-element required for the constitutive activity and osmotic response of the rat aldose reductase promoter.

A new and essential cis-element AEE (aldose reductase enhancer element), necessary for the constitutive activity and the osmotic stress response of rat aldose reductase transcription in a rat liver cell line, has been identified. In transient transfection assays, an increase in promoter activity, up to 3.8-fold, was observed with osmotic stress (600 mosm/kg H2O) using a luciferase reporter gene construct containing aldose reductase promoter sequence from -1,094 base pair (bp) to +23 bp. A deletion between -1,071 and -895 bp reduced the constitutive activity and abolished the osmotic response of the promoter. Exonuclease III mediated in vivo DNA footprinting and dimethyl sulfate in vivo footprinting revealed DNA protection of a 32-bp region and two guanosines (G) within this region protected from methylation, respectively. Electrophoretic gel mobility shift assays using whole liver cell extracts showed protein binding, under both normal and stressed conditions. Deletion of the sequence between the two guanosines protected by in vivo dimethyl sulfate DNA footprinting (GAAGAGTG) in a luciferase construct (-1,094 bp to +23 bp) abolished the constitutive promoter activity. One copy of AEE fused to the thymidine kinase promoter gave a maximum constitutive activity of 7.7-fold and a maximum osmotic response activity of 6. 7-fold.

Aldehyde Reductase↗
PubMed1997

Cloning of the gene for poly(3-hydroxybutyric acid) depolymerase of Comamonas testosteroni and functional analysis of its substrate-binding domain.

A poly(3-hydroxybutyric acid) (PHB) depolymerase gene of Comamonas testosteroni YM1004 was cloned on Sau3AI fragment from genomic DNA into Escherichia coli DH5. Nucleotide sequence analysis dedicated a 1539 bp open reading frame encoding a protein 513 amino acid with a putative 25 residue signal peptide for secretion. The deduced amino acid sequence was very similar to that of PHB depolymerase of Comamonas sp. In order to understand the characteristics of substrate-binding domain of the depolymerase, we constructed its glutathione S-transferase (GST) fusion protein and investigated the ability of adsorption on PHB single crystals by using gold-conjugated antibody and transmission electron microscopy. The fusion protein adsorbed on PHB single crystals tightly and homogeneously, suggesting that binding domain contributes to the adsorption of enzyme on solid PHB without site specificity.

Amino Acid Sequence↗
PubMed1997

Direct determination of estriol 3- and 16-glucuronides in pregnancy urine by column-switching high-performance liquid chromatography with fluorescence detection.

An HPLC method for the direct and simultaneous determination of estriol 3- and 16-glucuronides in pregnancy urine is described. The method is based on direct derivatization of the glucuronic acid moiety in estriol glucuronides in urine with 6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone-3-propionylcarboxylic acid hydrazide. The derivatization reaction proceeds in aqueous solution (or urine sample) in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide at 37 degrees C. The resulting fluorescent derivatives were separated by column-switching chromatography using a first column (YMC-Pack C4) for clean-up of the derivatives and a second column (YMC Pack Ph) for the complete separation of the derivatives. The derivatives were detected spectrofluorimetrically at 445 nm with excitation at 367 nm. The detection limits (signal-to-noise ratio=3) for estriol 3- and 16-glucuronides were 150 and 180 fmol in a 5 microl of urine (14 and 17 ng ml(-1) urine), respectively. The present method is highly sensitive and simple without any clean-up such as conventional solid-phase extraction.

Chromatography, High Pressure Liquid↗