PubMed Health⌕ Search

Biomedical subjects

T Miwa

Publications and source records attributed to T Miwa.

At least 19 recordsLinked to original sources
PubMed1992

A protein binding to CArG box motifs and to single-stranded DNA functions as a transcriptional repressor.

A CArG box motif [CC(A+T-rich)6GG] is one of the DNA elements required for muscle-specific gene transcription. Nuclear factors in mouse C2 myogenic cells strongly bind to the CArG box in the first intron of the gene (Sm alpha-A) encoding human smooth muscle alpha-actin. To clone cDNAs of the CArG box-binding factor (CBF), lambda gt11 cDNA expression libraries from C2 cells were screened for in situ DNA binding specific for this CArG box sequence. The 1.6-kb cDNA (CBF-A) encoding 285 amino acids (aa) was obtained, and a beta-galactosidase fusion protein, bacterially produced from the cDNA, bound to DNA fragments containing several CArG boxes. When the expression level of CBF-A in C2 cells increased by transfection of CBF-A expression plasmids, Sm alpha-A transcription was repressed. The deduced aa sequence of CBF-A is similar to some single-stranded (ss) nucleic acid-binding proteins. The fusion protein could bind to ssDNA, whereas CBF in C2 cell nuclear extracts could not. From these results, CBF-A is a novel CArG box-, ssDNA- and RNA-binding protein, as well as a repressive transcriptional factor.

Actins↗
PubMed1992

Conalbumin-conjugated silica gel, a new chiral stationary phase for high-performance liquid chromatography.

A new chiral stationary phase using conalbumin (from chicken egg white) was developed for high-performance liquid chromatography. Chiral resolution of racemic azelastine, an antiallergic drug, was achieved on a conalbumin-conjugated silica gel column. The effects of the pH, the concentration of organic solvents and salts in the mobile phase, and the temperature on the capacity factor and resolution of racemic azelastine were examined. This column shows good stability and can separate optical isomers with an aqueous mobile phase. It should be very useful in studies on pharmacokinetics and in clinical chemistry.

Chromatography, High Pressure Liquid↗
PubMed1992

Histochemical study of pituitary adenomas with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies, bromodeoxyuridine labeling, and nucleolar organizer region counts.

The growth potential of 65 pituitary adenomas was determined by histochemical analysis with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies, bromodeoxyuridine (BrdUdR) labeling, and counts of argyrophilic nucleolar organizer regions (Ag-NORs). The mean proliferating cell indices (PCIs) determined by Ki-67 and anti-DNA polymerase alpha and the BrdUdR labeling index (LI) were generally very low [1.0 +/- 0.2%, 1.1 +/- 0.2%, and 0.5 +/- 0.1% (+/- SE), respectively]. Apart from adrenocorticotropic hormone-positive adenomas, which had significantly higher indices, there were no statistically significant differences in the indices among the other subtypes of pituitary adenomas. Recurrent tumors had higher Ki-67 and DNA polymerase alpha PCIs and BrdUdR LIs (3.6%, 4.2%, 1.4%) than primary tumors (0.8%, 0.8%, 0.3%; P less than 0.005). The number of Ag-NORs did not correlate significantly with any of the three indices. The mean number of Ag-NORs was higher in nonfunctioning adenomas than in functioning adenomas (2.04 vs 1.66, P less than 0.005); among prolactin-positive adenomas, those treated preoperatively with bromocriptine had more Ag-NORs than untreated tumors (1.75 vs 1.57, P less than 0.005). These results suggest that the Ki-67 and DNA polymerase alpha PCIs and the BrdUdR LI predict the growth potential of individual pituitary adenomas, whereas the number of Ag-NORs appears to correlate with hormone production rather than with the proliferative potential.

Adenoma↗
PubMed1992

Effect of a prostaglandin I2 derivative (iloprost) on peripheral neuropathy of diabetic rats.

PGE1 has been found to improve the symptoms of diabetic neuropathy. We considered that a PGI2 derivative may also have a similar action and therefore studied its effect in diabetic rats. Iloprost was administered intraperitoneally to streptozotocin-induced diabetic rats at a dose of 10 micrograms/kg/day for a month. The changes in nerve conduction velocity (NCV) were measured in the tail. One day after the last dose of iloprost, both sciatic nerves were removed from each rat, homogenized, and extracted with 6% TCA. The sorbitol and myo-inositol concentrations were determined by a combination of HPLC and an enzymatic method. Cyclic AMP (cAMP) levels were determined by RIA, and Na+, K+ ATPase activity was assessed by the enzyme cycling method of Greene and Lattimer. Iloprost was found to improve the NCV in the diabetic rats. The sorbitol content was not affected by iloprost, but the myo-inositol content was higher in the iloprost group than in the untreated group, although the difference was not statistically significant. The Na+, K+ ATPase activity and cAMP content were significantly higher in the iloprost group than in the untreated group. These findings suggest the possibility that the cAMP-dependent protein kinase (A-kinase) system has an important influence on improvement in Na+, K+ ATPase activity.

Animals↗
PubMed1992

Carcinogenicity study of gamma-oryzanol in F344 rats.

The carcinogenic potential of gamma-oryzanol, a drug mainly used for the treatment of hyperlipidaemia, was studied in F344 rats. Groups of 50 males and 50 females were fed a diet containing 0 (control), 200, 600 or 2000 mg gamma-oryzanol/kg body weight/day for 2 yr. Although females in the highest dose group (2000 mg/kg body weight) showed a slight decrease in body weight at 104 wk, there were no treatment-related changes in general condition, food consumption, mortality, organ weight or haematology. Histopathological examination showed various tumours in all groups, including the control group. In the control and 2000-mg/kg groups, high tumour incidences were observed in the testes, pituitary and thyroid of males, and in the pituitary, uterus and mammary gland of females; however, there was no significant increase in the incidence of any tumours between the control and the 2000-mg/kg groups. The findings indicate that under the experimental conditions described gamma-oryzanol was not carcinogenic in F344 rats.

Administration, Oral↗
PubMed1992

Carcinogenicity study of gamma-oryzanol in B6C3F1 mice.

The carcinogenic potential of gamma-oryzanol, a drug mainly used for the treatment of hyperlipidaemia, was studied in B6C3F1 mice. Groups of 50 males and 50 females were fed a diet containing 0 (control), 200, 600 or 2000 mg gamma-oryzanol/kg body weight/day for 78 wk. No treatment-related changes were observed in general condition, body weight, food consumption, mortality, organ weight or haematology. Histopathological examinations showed various tumours in all groups, including the control group. In the control and 2000-mg/kg groups, relatively high tumour incidences were observed in the liver of males and in the haematopoietic organs of females. However, there was no statistically significant difference in the incidence of any tumours between the control and the 2000-mg/kg groups. The findings indicate that under the experimental conditions described gamma-oryzanol was not carcinogenic in B6C3F1 mice.

Administration, Oral↗
PubMed1992

Immunophenotypes of the palatal tonsil lymphocytes in Cowden's disease.

Cowden's disease is characterized by multiple hamartomas and neoplasias of ectodermal, mesodermal and endodermal origin. A case of a 22-year-old man suffering from nocturnal dyspnoea is reported. The patient had a large number of hyperkeratotic, lichenoid papules, scattered over the right side of the trunk, back and palm. In his oral cavity, papules were present on the gingiva and hard palate. The patient was operated on for tonsillar hypertrophy and for excluding the possibility of malignant lymphoma. An examination of immunophenotypes of the palatal tonsil lymphocytes revealed B-cell proliferation and poly-clonal immunoglobulin.

Adult↗
PubMed1992

Instrument myopia and the resting state of accommodation.

I measured the refractive errors of 210 eyes of 105 subjects by means of the Canon Autoref R-1 and by the Nikon autorefractometer NR7000. I also measured their dark focus of accommodation (DF) with the Canon instrument. Refractive errors had similar effects on the differences between the results produced by the two autorefractometers and on the changes in DF. The differences were statistically significant. Differences between the results produced by the two autorefractometers are thought to be mainly due to instrument myopia, which itself is strongly related to the resting state of accommodation. My results indicate a hyperopic shift in high hyperopes when they are observing through an instrument.

Accommodation, Ocular↗
PubMed1992

Synthesis and antiallergy activity of [1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-one derivatives. II. 6-Alkyl- and 6-cycloalkylalkyl derivatives.

A series of 6-alkyl- or 6-(cycloalkylalkyl)-[1,3,4]thiadiazolo[3,2- a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-ones 1b--o was synthesized from the corresponding 1,3,4-thiadiazol-5-amines 3b--o and the antiallergic activities of the products were evaluated. Among the compounds 6-(2-cyclohexylethyl)- [1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-one 1h, whose X-ray crystallographic stereostructure is shown, was found to be a promising new antiallergic agent, which has low toxicity and dual activity as a leukotriene D4 receptor antagonist and as an orally active mast cell stabilizer.

Animals↗
PubMed1992

Synthesis and antiallergy activity of [1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyrimidin-9 (3H)-one derivatives. I.

A series of 6-substituted [1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-one derivatives 4a--z were synthesized from 5-substituted 1,3,4-thiadiazol-2-amines 5 by the following consecutive reactions: pyrimidine ring closure with bis(2,4,6-trichlorophenyl) malonate, nitration, chlorination, amination, hydrogenation and diazotization. The structure of 4 was confirmed by an alternate synthesis of 4, involving reaction of 5-substituted 2-azido-1,3,4-thiadiazole 13 with ethyl cyanoacetate, followed by the Dimroth rearrangement and ring closure. The antiallergic activities (anti-passive peritoneal anaphylaxis, anti-passive cutaneous anaphylaxis and anti-slow reacting substance of anaphylaxis activities) of the products were evaluated.

Anaphylaxis↗
PubMed1992

Embedding and fixation techniques for immunohistochemical staining with anti-DNA polymerase alpha and Ki-67 monoclonal antibodies to analyze the proliferative potential of tumors.

Anti-DNA polymerase alpha and Ki-67 are monoclonal antibodies that recognize nuclear antigens expressed in proliferating cells. In this study, we evaluated various methods of embedding and fixing brain tumor specimens to optimize staining with these antibodies. In fresh frozen sections, postfixation with 4% paraformaldehyde, 100% methanol, 95% ethanol and 10% buffered formalin were tested; also tested were prefixation with 4% paraformaldehyde followed by freezing and fixation with 100% methanol, 95% ethanol, or 10% buffered formalin followed by embedding in paraffin. For both antibodies, postfixation of fresh frozen sections with 4% paraformaldehyde at 4 C gave the most intense staining and lowest background activity while preserving histological features. This technique can be used in routine clinical practice to predict the growth potential of tumors.

Antibodies, Monoclonal↗
PubMed1992

[Study of behavioral and histological change in mice following olfactory bulbectomy].

Behavioral and histological changes in mice following bilateral olfactory bulbectomy were studied. Mice were trained to discriminate between a 0.01% Cycloheximide solution and distilled water. After olfactory bulbs were removed, discrimination was lost, and had not returned 300 days after bulbectomy. The histological changes observed by light microscope were as follow. Degeneration of olfactory epithelium was observed immediately after the bulbectomy, followed by decrement of the epithelial thickness and the number of olfactory cells. An increase in both epithelial thickness and the number of olfactory cells was observed 14 days after the bulbectomy, and epithelial thickness 300 days after the bulbectomy was similar to that of the sham-operation group. At 300 days after the bulbectomy, axons of olfactory cells migrated through the lamina cribrosa, but didn't contact the forebrain. In this study, the olfactory bulb was considered to have played a role in functional recovery of olfactory behavior, and that olfactory cells were continuously renewed under conditions of target organ, i.e. olfactory bulb, loss.

Animals↗
PubMed1992

[Clinical observations on parosmia].

We reviewed the clinical records of 15 patients with parosmia examined in our department from April 1987 to September 1990. Seven (29.2%) of 24 patients with olfactory disturbance caused by traumatic injury complained of parosmia. Eight (23.2%) of 34 patients with olfactory disturbance caused by influenza also showed parosmia. The incidence of parosmia between two groups was not statistically significant (p greater than 0.05). Parosmia was observed in none of 42 patients with olfactory disturbance caused by nasal-paranasal diseases. All patients (n:15) always perceived odors as unpleasent. Twelve of them had spontaneous parosmia, and three patients recognized the unpleasant smell when an odor came. In comparison with the auditory system, we speculated that spontaneous parosmia resembles tinnitus. The cause of tinnitus is recognized as a disturbance of the auditory nerve (the first order neuron). Tinnitus is rare in patients with conductive hearing loss, and cases of olfactory disturbance of the "respiratory dysosmia" did not complain of parosmia. Post-traumatic olfactory disturbance is caused by transection of the fila olfactoria, which is part of an olfactory neuron, while post-inflammatory olfactory disturbance is caused by damage to olfactory receptor cells. Furthermore, the fact that the incidence of parosmia between the two groups was not statistically significant suggests the same etiological mechanism in receptor cells. We consider that parosmia is caused by damage to olfactory sensory neurons.

Adolescent↗
PubMed1992

[Endoscopic stage classification of peptic ulcer and characterization of the healing process by proton pump inhibitors].

Proton pump inhibitors are highly effective for gastric acid secretion and have been shown to be superior to histamine H2-receptor antagonists. The superiority of proton pump inhibitors over H2-receptor antagonists was more pronounced in duodenal ulcers. Omeprazole reduced the time required by H2-receptor antagonists the healing of duodenal ulcers by 2/3 to 1/2. On the other hand, unusual endoscopic findings, such as shallow white coat or protrusion of the ulcer floor, were noted in the healing stage of gastric ulcers with H2-receptor antagonists. Whereas these findings were rarely seen with conventional drugs. Histologically, the protrusion was made up granulation tissue consisting of cell infiltration and renewed capillaries with or without regenerated epithelia. These unusual endoscopic findings may be observed in the peptic ulcers treated with proton pump inhibitors.

Adenosine Triphosphatases↗
PubMed1992

[Study on adrenergic acid secretion using isolated parietal cells of guinea-pigs].

In order to investigate the effect of adrenergic nerve system on acid secretion at the cell-levels, acid secretion of isolated parietal cells stimulated by various adrenergic agonists was observed by measuring the accumulation of 14C-aminopyrine (A.P.). Both isoproterenol, beta receptor agonist, and salbutamol, beta-2 receptor selective agonist, increased A.P. accumulation, whereas dobutamine, beta-1 receptor selective agonist, showed no effect. And beta-2 receptor on parietal cells was detected by binding assay. These data may suggest that parietal cells have beta-2 receptors through which acid secretion will occur.

Adrenergic beta-Agonists↗
PubMed1992

[Effect of long-term administration of antisecretary drugs on rat gastric histamine synthesis and acid secretion--compare with omeprazole and cimetidine].

To investigate the effect of 6 weeks administration of proton pump inhibitor (omeprazole) and H2-receptor antagonist (cimetidine) on gastric histamine synthesis and acid secretion, we studied experimentally in the rat stomach. Then gastric mucosal histamine concentration, histidine decarboxylase (HDC) activity and serum gastrin concentration, and HDC positive cell number were examined in time-course. The 6 weeks administration of omeprazole caused more increase of HDC positive cells than cimetidine. After cessation of administration with omeprazole, high plasma gastrin level immediately reduced. However the increase of gastric mucosal HDC activity and histamine concentration were prolonged, compared with cimetidine. These findings suggest to affect differently between omeprazole and cimetidine on gastric acid secretion after cessation of long-term treatment.

Animals↗