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Biomedical subjects

M Hayakawa

Publications and source records attributed to M Hayakawa.

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

Discrete stages of anterior pituitary differentiation recapitulated in immortalized cell lines.

Targeted expression of oncogenes in transgenic mice can immortalize specific cell types to serve as valuable cultured model systems. Utilizing promoter regions from pituitary genes activated in the gonadotrope/thyrotrope lineage at discrete stages of development, we have demonstrated that targeted oncogene expression in transgenic mice can produce cell lines representing sequential stages of differentiation. Each cell line expresses a specific subset of the genes denoting differentiated function such as the subunits of the glycoprotein hormones, hormone receptors, and transcriptional regulatory proteins. These model systems have allowed detailed investigations into molecular and cellular mechanisms otherwise inaccessible in vivo or in complex primary pituitary cell cultures.

Animals↗
PubMed1998

Sequence analysis of the Porphyromonas gingivalis dipeptidyl peptidase IV gene.

We previously constructed a Porphyromonas gingivalis genomic library and isolated the 2.9 kb EcoRV fragment which specified glycylprolyl dipeptidyl aminopeptidase (GPase). Nucleotide sequencing of this fragment identified the single 2169 bp open reading frame which coded for a 723 amino acid protein. The amino acid sequencing of the NH2-terminal domain of the native and recombinant mature enzymes suggested that the protease possessed a 16 amino acid residue signal peptide. The calculated mass of the precursor and mature proteases were 82,018 and 80,235 daltons, respectively. The homology search of this enzyme in registered protein sequences revealed that this enzyme was homologous to dipeptidyl peptidase (DPP) IV from the Flavobacterium meningosepticum and that from eukaryotic cells, including the human, mouse, and rat. Three amino acid residues, Ser-593, Asp-668, and His-700, were identified as a putative catalytic triad, a common feature of eukaryotic serine proteases. In addition, this enzyme showed a broad proteolytic spectrum toward synthetic substrates capable of splitting not only Gly-Pro-derivative but also Ala-Pro, Lys-Pro, and Phe-Pro-derivatives. Therefore, we conclude that this enzyme belongs to DPP IV rather than GPase.

Amino Acid Sequence↗
PubMed1998

Application of the resident plasmid integration technique to construct a strain of Streptococcus godronii able to express the Bacillus circulans cycloisomaltooligosaccharide glucanotransferase gene, and secrete its active gene product.

A novel transformation technique, resident plasmid integration, for the cloning of foreign DNA in oral streptococci was described recently (T. Shiroza and H.K. Kuramitsu, Plasmid 34 (1995) 85-95. This technique is based on the integration of linearized foreign genes by recombination-proficient bacteria onto a resident plasmid, if an appropriate selection marker is flanked by the same anchor sites present in the resident plasmid. Since the transforming vehicles for this system included a pUC-derived replication origin, the high level expression in Escherichia coli cells hindered the cloning of certain genes. In the present study, new plasmids were constructed, two resident plasmids, four integration plasmids, and four cloning plasmids, all of which possess the medium-copy number replication origin, p15A ori, isolated from pACYC177. The resident plasmids consisted of the following three components: the p15A ori (0.65-kb Bg/II fragment), the pVA380-1 basic replicon functional in mutans streptococci (2.5-kb BamHI fragment), and either an erythromycin resistance or a spectinomycin resistance gene (0.9- or 1.1-kb BamHI fragment, respectively). Most of the basic replicon of pVA380-1, except for the 3'-portion of the 0.2-kb region, in the resident plasmid was replaced with a kanamycin resistance gene to construct the four integration plasmids. Therefore, the upstream and downstream anchor sites for the double cross-over event in this new system were 0.65-kb p15A ori and the 0.2-kb portion of the 3'-end of pVA380-1 replicon, respectively. This system was used to clone the gene coding for cycloisomaltooligosaccharide glucanotransferase which produces cycloisomaltooligosaccharide, a potent inhibitor of oral streptococcal glucosyltransferase, isolated from Bacillus circulans chromosome, into Streptococcus gordonii, and its gene product was successfully secreted into the culture media. Plasmids described here should be useful tools for introducing heterologous DNA into resident plasmids following integration in oral streptococci.

Bacillus↗
PubMed1998

Japanese juvenile retinoschisis is caused by mutations of the XLRS1 gene.

We investigated the XLRS1 gene in Japanese patients with retinoschisis (RS). All exons of the XLRS1 gene were sequenced in 14 males, including a pair of monozygotic twins, from 11 individual families with RS and five of their mothers who are asymptomatic but diagnosed as carriers. Six kinds of missense mutations and a nonsense mutation, including six novel mutations, were detected in all 14 patients and carriers. Mutations in the XLRS1 gene are also responsible for RS in non-Caucasian patients. Most Japanese RS cases are caused by an XLRS1 gene defect. A novel mutation, Glu72Lys, was found in four families, suggesting a common mutation in the Japanese population. Clinical features of RS patients with both the Glu72Lys and Pro193Leu mutations indicate that a genotype-phenotype correlation is not recognized in RS.

Eye Diseases, Hereditary↗
PubMed1998

An alternative procedure for the creation of an ileal conduit in patients undergoing pelvic exenteration: dextrotransmesenteric location.

Ileal conduits have long been accepted as a standard method for urinary diversion, but conventional ileal conduits are not always suitable for patients whose ureters are for the greater part compromised by neoplasm or preoperative irradiation, resulting in a shortening of the ureters. Bowel migration into the large cavity, which develops after pelvic organ removal, appears to cause tension on the ureteroileal anastomotic site. Dextrotransmesenteric placement of an ileal conduit may provide easy access to the shortened ureters without exerting pressure on the anastomosis. We employed this procedure in seven patients undergoing pelvic exenteration with relatively minimal morbidity.

Adult↗
PubMed1998

Recurrent dorsal angulation of the distal radius fracture during dynamic external fixation.

Thirty-three fractures of the distal radius treated with a dynamic external fixator (that allowed for wrist motion between 2 to 4 weeks after surgery) were analyzed, focusing on loss of fracture reduction during external fixation. Fractures with preoperative dorsal angulation greater than 20 degrees and those involving the distal radioulnar joint had a significantly larger loss of reduction of dorsal angulation (8.9 degrees and 6.9 degrees, respectively) than fractures with less severe preoperative dorsal angulation or those with an intact distal radioulnar joint (3.0 degrees and 2.6 degrees, respectively). In contrast, preoperative radial shortening (>2 mm) and involvement of the radiocarpal joint did not significantly increase the loss of dorsal angulation. Neither of the 2 dynamic external fixation systems studied consistently stabilized Colles' fractures with preoperative dorsal angulation of greater than 20 degrees or involvement of the distal radioulnar joint.

Adult↗
PubMed1998

Cytokine levels in cystic renal masses associated with renal cell carcinoma.

PURPOSE: We compared cytokine levels in fluid from renal cysts with and without renal cell carcinoma. MATERIALS AND METHODS: Fluid was aspirated from 18 renal cysts without (benign) and 21 with renal cell carcinoma (malignant). Serum from patients with renal cell carcinoma and healthy controls was collected and cytokines were measured by enzyme-linked immunosorbent assay. RESULTS: Interleukin-6 (IL-6) and basic fibroblast growth factor concentrations were higher in malignant than benign cysts or serum (p <0.006). Epidermal growth factor levels were significantly higher in malignant cysts and serum than in benign cysts (p <0.01). IL-6 levels in malignant cysts positively correlated with the erythrocyte sedimentation rate (R=0.80) and C-reactive protein (R=0.86), and they were higher in grade 3 than in grade 2 tumors. Basic fibroblast growth factor levels were significantly higher in malignant cysts associated with hypervascular than hypovascular tumors (p=0.029). CONCLUSIONS: Cytokine levels in aspirated fluid may help to identify malignant renal cysts and indicate the characteristics of coexisting tumors.

Adult↗
PubMed1998

A new genus of the order Actinomycetales, Cryptosporangium gen. nov., with descriptions of Cryptosporangium arvum sp. nov. and Cryptosporangium japonicum sp. nov.

Four strains that form sporangia with motile sporangiospores and mycelia were isolated from soil samples. Their many sporangia were covered by mycelia. They had glutamic acid, glycine, alanine and meso-diaminopimelic acid as cell wall amino acids (wall chemotype II), acofriose (3-O-mythylrhamnose) as a characteristic whole-cell sugar, and menaquinone 9(H6). The taxonomic characteristics of these strains differ from those of the previously described motile actinomycetes. On the basis of the morphological, physiological, chemotaxonomic and phylogenetic analyses, a new genus is proposed, Cryptosporangium, and two new species, Cryptosporangium arvum sp. nov (type strain IFO 15965T) for strain YU 629-21T and Cryptosporangium japonicum sp. nov (type strain IFO 15966T) for strains YU 636-3T, YU 655-31 and YU 656-31.

Actinomycetales↗
PubMed1998

Simultaneous presentation of malignant lymphoma of the kidney and multiple myeloma of the bone marrow.

We report a case of coexisting renal lymphoma and multiple myeloma. A 77-year-old man was referred to our hospital with a diagnosis of cancer in his right kidney. Biopsies of the renal mass and bone marrow were performed because of hyperproteinemia and biclonal gammopathy. Immunohistochemical staining and Southern blot analysis of the tumor's DNA were diagnostic for renal lymphoma. To our knowledge, this is the first time the coexistence of malignant renal lymphoma and multiple myeloma has been reported.

Aged↗
PubMed1998

Selective muscarinic antagonists. I. Synthesis and antimuscarinic properties of 4-piperidyl benzhydrylcarbamate derivatives.

A series of 1-substituted-4-piperidyl benzhydrylcarbamate derivatives were synthesized and evaluated for binding affinity to M1, M2 and M3 receptors, and for antimuscarinic activities. Receptor binding assays indicated that 1-benzyl-4-piperidyl benzhydrylcarbamate derivatives showed higher affinities for M1 and M3 receptors, and good selectivities for M3 over M2 receptor, than the corresponding ester analog. These results indicate that the urethane bond is a novel linker for muscarinic antagonists, and serves to lock the molecular conformation and allows the hydrophobic portion and cationic site of the molecule to bind to M1 and M3 muscarinic receptors. Among the prepared compounds, 1-(4-methylaminobenzyl)-4-piperidyl benzhydrylcarbamate monohydrochloride (18b, YM-58790) exhibited potent inhibitory activity on bladder pressure in reflexly-evoked rhythmic contraction, comparable to oxybutynin and was approximately ten times less inhibitory on oxotremorine-induced salivary secretion than oxybutynin in rats. Further evaluation of antimuscarinic effects on bradycardia and pressor in pithed rats, and on tremor in mice, demonstrated that YM-58790 can be useful for treatment of urinary urge incontinence as a bladder-selective M3 antagonist with fewer side effects.

Animals↗
PubMed1998

Selective muscarinic antagonists. II. Synthesis and antimuscarinic properties of biphenylylcarbamate derivatives.

A novel series of biphenylylcarbamate derivatives were synthesized and evaluated for binding to M1, M2 and M3 receptors and for antimuscarinic activities. Receptor binding assays indicated that biphenyl-2-ylcarbamate derivatives had high affinities for M1 and M3 receptors and good selectivities for M3 receptor over M2 receptor, indicating that the biphenyl-2-yl group is a novel hydrophobic replacement for the benzhydryl group in the muscarinic antagonist field. In this series, quinuclidin-4-yl biphenyl-2-ylcarbamate monohydrochloride (8l, YM-46303) exhibited the highest affinities for M1 and M3 receptors, and selectivity for M3 over M2 receptor. Compared to oxybutynin, YM-46303 showed approximately ten times higher inhibitory activity on bladder pressure in reflexly-evoked rhythmic contraction, and about 5-fold greater selectivity for urinary bladder contraction against salivary secretion in rats. Moreover, selective antagonistic activity was also observed in vitro. Further evaluation of antimuscarinic effects on bradycardia and pressor in pithed rats, and on tremor in mice, showed that YM-46303 can be useful for the treatment of urinary urge incontinence as a bladder-selective M3 antagonist with potent activities and fewer side effects.

Animals↗
PubMed1998

[2-(omega-phenylalkyl)phenoxy]alkylamines: synthesis and dual dopamine2 (D2) and 5-hydroxytryptamine2 (5-HT2) receptor antagonistic activities.

A series of [2-(omega-phenylalkyl)phenoxy]alkylamines was synthesized and their 5-hydroxytryptamine2 (5-HT2) and/or dopamine2 (D2) receptor antagonistic activities were examined in vitro. [2-(4-Phenylbutyl)phenoxy]alkylamines showed strong inhibition of both 5-HT2 and D2 receptors. In particular, [2-(4-Phenylbutyl)phenoxy]-methylpiperidine derivatives, 10b, 10i and 10q, exhibited potent inhibition. The structure-activity relationships in this series of compounds are discussed.

Amines↗
PubMed1998

Low density lipoprotein particle size is associated with glycosylated hemoglobin levels regardless of plasma lipid levels.

We evaluated the influence of the levels of glycosylated hemoglobin (HbA1C) and fasting plasma glucose on the variation in low density lipoprotein (LDL) peak particle size in 210 subjects who were undergoing an annual check-up. Univariate analysis showed that LDL particle size was significantly and positively correlated with high density lipoprotein (HDL) cholesterol levels, and was inversely correlated with the levels of total plasma cholesterol, triglycerides, fasting glucose, fasting insulin, HbA1C, and body mass index (BMI). Stepwise regression analysis selected four independent contributing variables that could affect LDL particle size; triglyceride levels, HDL cholesterol levels, LDL cholesterol levels, and HbA1C levels. Similar regression analysis performed for men and for normotensive subjects showed that HbA1C levels also independently influenced LDL particle size. The results indicate that HbA1C levels have a significant effect on LDL particle size. This suggests that small LDL particles would be present in subjects with non-insulin-dependent diabetes mellitus regardless of plasma lipid concentrations.

Adult↗
PubMed1998

Treatment and results of partially thrombosed giant aneurysms.

Partially thrombosed giant aneurysms are one of the most difficult diseases in the neurosurgical field. We have had 18 of these cases namely, three in vertebral artery, four in basilar artery, four in internal carotid artery, five in middle cerebral artery, and two in anterior communicating artery. Nine aneurysms were clipped, two aneurysms were removed with anastomosis, two cases were treated interventionally, and five cases were treated conservatively because of serpentine and fusiform types of aneurysms in internal carotid artery bifurcation. These conservatively treated patients died due to infarction. When surgery is selected in the thrombosed giant aneurysms, the approach is the most important to secure the neck. Three-dimensional computed tomography angiography was useful to plan the strategy for surgery. If the neck is big enough for placement of a clip, arterial reconstruction is the choice. The reconstruction must be done including an adequate size of the artery because of the thick wall. If the aneurysm neck is too small to reconstruct, aneurysmectomy with anastomosis is one of the choices.

Adult↗
PubMed1998

Castability of a commercial castable glass ceramics.

This study was carried out to determine the design and thickness of the cervical margin of a castable ceramic restoration from the point of view of its castability. Castability of castable ceramics was lower compared to Ag-Pd-Au and Co-Cr alloy with the use of the mesh pattern and rod pattern test (p < 0.05). It was more dependent on the pattern thickness than alloys (p < 0.05), and perfect reproducibility with non-measurable variability could be estimated to reach 1.0 mm thickness of the original pattern (p < 0.001). Marginal shape was certainly more reproducible in a right angle shoulder than in 30, or 45 degree bevels (p < 0.05). From these results, it is suggested that a right angle shoulder margin with 1.0 mm thickness is more suitable to castable glass ceramic restoration than any other design.

Analysis of Variance↗
PubMed1998

[A case report of complete inversion of the bladder in an old woman].

A 77-year-old Japanese woman was admitted to our hospital complaining of small urinary volume. Physical examination revealed a light red, edematous, pyriform mass, approximately 7 cm in diameter at the vulva. An orifice posterior to the base of the mass was catheterized and 20 ml of urine was obtained. Roentgenograms of contrast material injection to the orifice demonstrated a space of 20 ml. A diagnosis of complete inversion of the bladder was made. Under epidural anesthesia, attempts were made to reduce the mass through the urethra. The manual reduction proved to be difficult, but was successful by manual compression of the bladder wall and squeezing it back through the urethra, which took approximately 60 minutes. Complete transurethral inversion of the bladder is so rare that not much of the pathogenesis is clarified. In our patient, senility, obesity, multiple labor and surgeries are assumed to have resulted in laxity of the pelvic wall which would be one of the major risk factors for this condition.

Aged↗