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Y Wada

Publications and source records attributed to Y Wada.

At least 757 records · Page 42Linked to original sources
PubMed1992

[Microspectrophotometric analysis of DNA content in duct epithelial proliferation and invasive carcinoma of the pancreas].

Nuclear DNA content of 131 pancreatic duct epithelial lesions, including 10 normal ducts, 30 intraductal proliferations with mild atypia (groups I-II), 30 with moderate atypia (group III), 24 with severe atypia (group IV), 14 of carcinoma in situ (group V), and 23 invasive carcinomas, was analyzed using microspectrophotometry. DNA histograms were classified into diploid, polyploid and aneuploid patterns. All of normal duct epithelia showed diploidy. Polyploid patterns were observed in 3 (10%) lesions of groups I-II, 17 (56.7%) of group III, 14 (58.4%) of group IV, 7 (50%) of group V, and 6 (26.1%) of invasive carcinomas, and aneuploid patterns were observed in 0%, 10%, 33.3%, 50% and 73.9%, respectively. This distribution of ploidy patterns revealed a gradual shift to the main ploidy from diploid to polyploid followed by aneuploid in proportion to the increase of the degree of epithelial atypia. The frequencies of polyploid cells in each lesion were determined. Their averages were 0.2% in groups I-II, 1.9% in group III, 3.4% in group IV, 4.4% in group V, and 6.7% in invasive carcinoma. The S+G2M phase fractions were significantly higher in proliferative epithelia than in normal. The results of this study suggest that duct epithelial proliferations of the pancreas have "genetic instability" leading to a serial clonal evolution and play a significant role in the progression of pancreatic duct cell carcinoma.

Carcinoma in Situ↗
PubMed1991

Cloning of the human erythropoietin receptor gene.

We have isolated and characterized a genomic clone of the human erythropoietin (Epo) receptor from a placental genomic library using a cDNA probe for the murine Epo receptor. The coding region spans about 6.5 kb with seven intervening sequences ranging in size from 81 bp to 2.1 kb. A stretch of 123 purines is found in the 5' region from -456 to -578 upstream from the first codon and flanking the Alu repetitive sequences located further upstream. The human Epo receptor contains a palindromic sequence 5' of the translated region that consists of an almost perfect inverted repeat of 12 nucleotides (CAGCTGC(G/C)TCCG) centered about G at -92 from the first codon. An inverted SP1 binding site (CCGCCC) and an inverted GATA-1 binding site (TTATCT) are located at positions -151 and -179, respectively, and CACCC sequences are located at -585 and further upstream. No TATA or CAAT sequences are in this 5' flanking region. However, this region as far as -275 has a 72% GC content compared with an overall GC content of 56%. A 1-kb BamHI fragment of the human Epo receptor containing 700 bp of sequences 5' of the coding region was transcribed in an in vitro transcription assay; initiation of transcription appeared to be around 132 +/- 5 just downstream from the inverted SP1 site at -151. T1 analysis of human Epo receptor messenger RNA also maps the site of transcription initiation to this region. Within 180 nucleotides 5' to the first exon are three regions with 70% or greater homology with the murine Epo receptor. The study of this gene, including its similarities with the murine Epo receptor, should help elucidate aspects of the transcriptional and possible translational control of the Epo receptor in human erythroid cells and thus its role in signal transduction and erythroid differentiation.

Amino Acid Sequence↗
PubMed1991

Tumor rejection antigens on BALB3T3 cells transformed by activated oncogenes.

The clonal expression of tumor rejection Ag (TRA) was analyzed on nine different clones derived from parental BALB3T3 cells that were transfected with activated H-ras, polyoma middle T (PyMT), c-myc, and v-src oncogenes. It was shown that Bras-h clone, which is an activated H-ras oncogene-induced transformant, expressed TRA as assessed in the transplantation study using syngeneic BALB/c mice. This TRA was not detected on parental BALB3T3 nontransformed cells, suggesting that TRA could be expressed in the BALB3T3 cell transformation. Furthermore, the cross-protection experiments indicated that this TRA was also conferred on other BALB3T3 transformants with high anchorage-independent growth potential such as an activated H-ras transformant Bras-d, and PyMT transformants BMT-f, BnMT-11, BnMT-20, except in the case of one H-ras transformant Bnr-12. In contrast, this TRA was not expressed on the transfectants with little or no anchorage independent growth potential such as a PyMT transfectant BnMT-4, a c-myc transfectant Bmyc-7, and a v-src transfectant Bsrc-7. We developed the mAb BRH19 that could react with TRA+ clones but not with TRA- clones. This mAb makes an immunoprecipitate, which is composed of a 50-kDa single polypeptide chain from Bras-h cell lysate. An injection to mice with this antigen could confer the protection against Bras-h challenge. These data indicate that the 50-kDa putative TRA molecule could be expressed in close association with the cell transformation, irrespective of the introduced oncogenes, and there may exist some regulatory mechanisms rather than individually distinct manners for the expression of TRA.

3T3 Cells↗
PubMed1991

Automated determination of orotic acid, uracil and pseudouridine in urine by high-performance liquid chromatography with column switching.

A column-switching high-performance liquid chromatographic method, requiring no sample preparation apart from filtration, is described for quantification of urinary orotic acid, uracil and pseudouridine. The analyses were carried out using a reversed-phase octadecylsilane-bonded column for sample clean-up and a cation-exchange column for separation; 5-20 microliters samples of urine were directly analysed, and more than 100 samples could be analysed consecutively. Each sample required only 30 min. Detection limits of these compounds were 5 pmol. Creatinine-related urinary uracil excretion was lowest in the newborn period (17.3 +/- 14.4 mumol/g of creatinine). A patient with partial ornithine transcarbamylase deficiency and his mother usually excreted a high level of uracil during the period of normal orotic acid excretion and normal serum ammonia level.

Adolescent↗
PubMed1991

Suppressive effects of L-5-hydroxytryptophan in a feline model of photosensitive epilepsy.

We recently demonstrated that long-lasting photosensitivity is acquired as a result of kindling of the lateral geniculate nucleus (LGN), and that the LGN-kindled cat pretreated with D, L-allylglycine represents a useful model of epilepsy for drug studies. The present experiments studied anticonvulsant effects of a serotonin precursor, L-5-hydroxytryptophan (5-HTP), on photosensitivity in the LGN-kindled cat under D,L-allylglycine and on LGN-kindled seizures. 5-HTP suppressed both myoclonic responses and paroxysmal EEG discharges induced by photic stimulation in a dose-related manner. Photically-induced seizures were completely blocked 1.5-2 h after injection of 20 mg/kg 5-HTP. 5-HTP was also effective in reducing the afterdischarge duration and behavioral seizure stage in LGN-kindled seizures; following 40 mg/kg administration, no electroclinical seizures were elicited in the LGN-kindled cats. Serotonergic mechanisms may play an important role in epileptic photosensitivity; the 5-HTP suppressive effect on photosensitivity is at least partly due to reduced neuronal activity at the level of the LGN via serotonergic inhibition.

5-Hydroxytryptophan↗
PubMed1991

Distinct clustering of point mutations in mitochondrial DNA among patients with mitochondrial encephalomyopathies and with Parkinson's disease.

The total sequence data for mitochondrial DNA (mtDNA) revealed distinct clustering of point mutations (pms) in mtDNA among one patient with myoclonus epilepsy with ragged-red fibers (MERRF), two patients with Parkinson's disease (PD), two patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and one patient with fatal infantile cardiomyopathy (FICM). Among 33 to 62 pms found in each patients, sequentially diverged five clusters of pms were detected and designated as C-1 to C-5. C-1, consisted of fourteen pms, existed in the MERRF patient, C-1 and C-2 (nine pms) in one PD patient, C-1 to C-3 (seven pms) in another PD patient, C-1 to C-4 (one pm) in one MELAS patient and C-1 to C-5 (three pms) in another MELAS patient and the FICM patient. From these clustering of pms, a phylogenetic tree of mitochondrial encephalomyopathies (ME) was constructed. This tree clearly indicated that the ME and PD patients are members of the same gene family, and the MELAS and FICM patients are each others' closest relative. Each patient's unique pms (14 to 28 pms) were detected and, from their characteristic features, the types of the mutations specific for the disease were classified as mit- + syn- for MERRF, mit- + p- for PD, and syn- + mit- for MELAS. An inverse relation was found between the total number of pms and life span of the MELAS and FICM patients.

Adolescent↗
PubMed1991

Site-directed mutagenesis in haemoglobin. Functional role of tyrosine-42(C7) alpha at the alpha 1-beta 2 interface.

To clarify the functional role of Tyr-42(C7) alpha, which forms a hydrogen bond with Asp-99(G1) beta at the alpha 1-beta 2 interface of human deoxyhaemoglobin, we engineered two artificial mutant haemoglobins (Hb), in which Tyr-42 alpha was replaced by Phe (Hb Phe-42 alpha) or His (Hb His-42 alpha), and investigated their oxygen binding properties together with structural consequences of the mutations by using various spectroscopic probes. Like most of the natural Asp-99 beta mutants, Hb Phe-42 alpha showed a markedly increased oxygen affinity, a reduced Bohr effect and diminished co-operativity. Structural probes such as ultraviolet-region derivative and oxy-minus-deoxy difference spectra, resonance Raman scattering and proton nuclear magnetic resonance spectra indicate that, in Hb Phe-42 alpha, the deoxy T quaternary structure is highly destabilized and the strain imposed on the Fe-N epsilon (proximal His) bond is released, stabilizing the oxy tertiary structure. In contrast with Hb Phe-42 alpha, Hb His-42 alpha showed an intermediately impaired function and only moderate destabilization of the T-state, which can be explained by the formation of a new, weak hydrogen bond between His-42 alpha and Asp-99 beta. Spectroscopic data were consistent with this assumption. The present study proves that the hydrogen bond between Tyr-42 alpha and Asp-99 beta plays a key role in stabilizing the deoxy T structure and consequently in co-operative oxygen binding.

Hemoglobins↗
PubMed1991

Calculated two-dimensional sugar map of pyridylaminated oligosaccharides: elucidation of the jack bean alpha-mannosidase digestion pathway of Man9GlcNAc2.

We have developed a two-dimensional (2-D) mapping of pyridylaminated oligosaccharides as an aid to structural determination of glycoprotein-derived oligosaccharides. Using the available data of reverse-phase HPLC of pyridylamino-oligosaccharides, this was further extended to parameterization of unit contribution by each sugar component, which allows the prediction of possible structures from the elution volume. We have extended this approach to the data obtained with amide-silica HPLC column to obtain a calculated 2-D mapping technique for the oligomannose-type oligosaccharides (M-series). In this method, the elution volumes of all possible pyridylamino-oligosaccharides up to the size of Glc1Man9GlcNAc2 (50 in total) are calculated from the established UC values to construct a 2-D map. To test the validity of the calculated 2-D map, the structures of intermediate PA-oligosaccharides generated during the alpha-mannosidase (jack bean) digestion of Man9GlcNAc2 (porcine thyroglobulin) were analyzed to establish the digestion pathway. The validity of this approach is substantiated by an independent deduction of the intermediate structures based on structural relationships and the coincidence of elution volumes. Our results agree well with the recently published digestion pathway of Man5GlcNAc2 by the same enzyme and that of Man9GlcNAc2 by lysosomal alpha-mannosidase.

Carbohydrate Sequence↗
PubMed1991

Mitochondrial DNA mutations in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS).

The total sequences of mitochondrial DNA were determined in two patients with juvenile-onset mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) due to Complex I deficiency. Patients 1 and 2 had three and two unique point mutations, respectively, causing replacement of phylogenically conserved amino acids. A transition from G to A was found at nucleotide position 5601 in the alanine tRNA gene of Patient 2, and a transition from A to G was found at 3243 in the leucine (UUR) tRNA gene of both patients. The latter mutation located at the phylogenically conserved 5' end of the dihydrouridine loop of the tRNA molecule, and was present in two patients with adult-onset MELAS and absent in controls. These results indicate that a mass of mtDNA mutations including the A-to-G transition in the tRNA(Leu) gene is a genetic cause of MELAS.

Adolescent↗
PubMed1991

Analysis of acylcarnitines in maternal urine for prenatal diagnosis of glutaric aciduria type 2.

The urinary acylcarnitine profiles of two mothers whose first children were diagnosed to have glutaric aciduria type 2 (multiple acyl-CoA dehydrogenation deficiency, electron transfer flavoprotein (ETF) deficiency) were analysed in the second pregnancy. Large volumes of tigrylcarnitine and isovalerylcarnitine and a little glutarylcarnitine were detected. Each fetus was also diagnosed to be abnormal by enzyme activity and immunoassay of ETF protein. The acylcarnitines in the mothers' urine disappeared in 1 week after labour or artificial abortion. Acylcarnitines were never detected in the urine of controls.

Abortion, Induced↗
PubMed1991

Radiation myelopathy: significance of gadolinium-DTPA enhancement in the diagnosis.

We described two cases of chronic progressive radiation myelopathy (CPRM), in which magnetic resonance imaging (MRI) was of great value for the diagnosis. Gadolinium-DTPA (Gd-DTPA) enhancement delineated precise lesions responsible for Brown-Séquard syndrome caused by CPRM in both cases. This safe, sensitive procedure will be a requisite study in patients who are suspected of CPRM.

Aged↗
PubMed1991

Surgical experience with nonparasitic cysts of the liver--the characteristics and constituents of cyst fluid.

Fifteen patients with nonparasitic hepatic cysts underwent surgery to relieve abdominal complaints, at the First Surgical Department, Tokyo University Hospital between 1966 and 1989. Total removal of the cyst was carried out in 14 of the patients, while puncture and aspiration only were performed in the other patient in whom a cyst had ruptured spontaneously, after which hemoperitoneum was observed at emergency laparotomy. The size of the cysts varied from 7-19 cm with a mean of 12.4 cm. Histological study revealed a congenital cyst in 14 patients and a cystadenoma in one. The epithelium lining of the internal surface of the congenital cysts was highly atrophic and desolated and often disappeared. Examination of the cyst fluid revealed the same concentration of electrolytes as in the serum. Hepatic enzyme levels were usually lower than in the serum, but lactic dehydrogenase and aminotransferase levels were elevated in a few cases. Tumor marker levels of the cyst fluid were higher than those in the serum in four of five patients examined.

Adult↗