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Biomedical subjects

H Miura

Publications and source records attributed to H Miura.

At least 19 recordsLinked to original sources
PubMed1992

An abasic site analogue activates a c-Ha-ras gene by a point mutation at modified and adjacent positions.

Synthetic c-Ha-ras genes with an analogue of an abasic site in the first or the second position of codon 12, or in the second position of codon 61 were constructed and transfected into NIH3T3 cells. The genes with the lesions in codon 12 exhibited more focus formation than a normal c-Ha-ras gene, while the gene with the lesion in codon 61 did not. Transformed cells were isolated from the foci, and the c-Ha-ras genes present in the transformants were analysed. A point mutation to A in the modified position was found most frequently in the cases of ras genes modified in codon 12. Surprisingly, point mutations in the adjacent position were also detected. These results indicate that dTMP, and not dAMP, was mainly incorporated into the sites opposite to the abasic site analogue, and that incorrect deoxynucleotides were incorporated in the position adjacent to the abasic site analogue.

3T3 Cells↗
PubMed1992

Induction of mutation of a synthetic c-Ha-ras gene containing hypoxanthine.

The second base of codon 61 of a synthetic c-Ha-ras gene was replaced with a hypoxanthine residue in a site-specific manner. Transfection of this gene into NIH3T3 cells by the calcium phosphate procedure resulted in increased focus formation. Total DNA was extracted from transformed cells, and the sequences of the inserted c-Ha-ras DNA were analyzed by the polymerase chain reaction-single-strand conformation polymorphism method. Mutations with A (or hypoxanthine) to G transition were detected exclusively. These results suggest that the synthetic c-Ha-ras gene can be used for investigations of mutagenesis caused by DNA lesions.

3T3 Cells↗
PubMed1992

Fine-needle aspiration cytology of metastatic breast tumor originating from leukemia.

Two cases of metastatic breast tumor originating from leukemia are reported. Fine-needle aspiration (FNA) specimens showed a large number of isolated small-to-medium-sized atypical lymphocytic cells. It is difficult to distinguish metastatic breast tumors and primary breast cancers by physical findings alone. FNA cytology is an effective method for qualitative diagnosis. When atypical lymphocytic cells are obtained in aspiration materials of the breast, past history and general examination are necessary for diagnosis. In some cases of leukemia with breast involvement, good outcomes are obtained. Therefore, earlier detection is necessary in order to begin suitable therapy earlier and to avoid unnecessary excisional biopsy in patients with leukemia and breast tumors. To achieve this it is also necessary to first take into consideration the possibility of metastasis or infiltration of leukemia, and second to prepare two types of specimen for Papanicolaou stain and Giemsa stain before operation.

Biopsy, Needle↗
PubMed1992

Inhibition by noradrenaline and adrenaline of the increase in glucose and lactate output and decrease in flow after sympathetic nerve stimulation in perfused rat liver: possible involvement of protein kinase C.

In perfused rat liver stimulation of the hepatic nerve plexuses increased via alpha 1-receptors glucose and lactate output decreased flow and caused an overflow of noradrenaline into the hepatic vein. Infusion of noradrenaline and adrenaline also elicited similar metabolic and hemodynamic alterations via alpha 1-receptors, whereas infusion of isoproterenol via beta 2-receptors enhanced glucose output and slightly reduced lactate release without affecting flow. The influence of circulating catecholamines on the nerve stimulation-dependent changes was investigated. Noradrenaline (100 nmol/L) or adrenaline (40 nmol/L) but not isoproterenol (1 mumol/L), which themselves caused about half-maximal alterations, strongly inhibited the nerve stimulation-induced increase in glucose and lactate output and decrease in flow but had no effect on noradrenaline overflow. The protein kinase C activator (4 beta)phorbol 12-myristate, 13-acetate (100 nmol/L) but not its analog (4 alpha)phorbol 12,13-didecanoate (100 nmol/L) strongly inhibited the metabolic and hemodynamic changes caused by nerve stimulation or noradrenaline infusion. The protein kinase C inhibitor H7 (20 mumol/L) partially prevented the inhibition of the nerve actions by noradrenaline. The results lead us to conclude that noradrenaline and adrenaline inhibited the metabolic and hemodynamic nerve actions by means of a mechanism involving protein kinase C rather than presynaptic alpha-receptors or beta-receptors. The catecholamines apparently increased via alpha 1-receptors inositol 1,4,5-trisphosphate, which in turn enhanced cytosolic Ca2+ and thus altered metabolism and in part hemodynamics, and diacylglycerol, which in turn activated protein kinase C and thus feedback inhibited the signal chain from alpha 1-receptors via G proteins to phospholipase C.

Animals↗
PubMed1992

Transcatheter hepatic arterial chemoembolization using epirubicin-lipiodol: experimental and pharmacological evaluation.

The experimental and pharmacological characteristics of various formulations of an anticancer agent (epirubicin, EPI) and lipiodol were evaluated in vitro and in vivo. Three forms of EPI-lipiodol, i.e., an oil-in-water type of emulsion (O/W type), a water-in-oil type of emulsion (W/O type), and a suspension (S type), were prepared and investigated for their stability. An O/W-type emulsion using a stock solution of Iopamidol as the solvent for EPI was the most stable form in the stationary state in vitro. In 16 patients with malignant liver tumors (14 hepatocellular carcinomas and 2 liver metastases), the three forms of EPI-lipiodol were injected into the proper hepatic artery. The plasma EPI level was monitored periodically and analyzed pharmacokinetically. No significant difference in the pharmacokinetics of EPI was detected among the O/W, W/O, and S types.

Aged↗
PubMed1992

An immunodominant haptenic epitope of carbamazepine detected in serum from patients given long-term treatment with carbamazepine without allergic reaction.

An anticarbamazepine antibody was detected in the serum of a patient with severe carbamazepine-induced serum sickness. We found that the patient's T cells and IgG antibody recognized an epitope which appeared in subjects showing an allergic reaction, as well as that in subjects who showed no allergic reaction, after long-term carbamazepine therapy. These results show that an anti-carbamazepine immune response does not occur in the majority of subjects who undergo long-term carbamazepine therapy without developing allergic symptoms, although the immunodominant haptenic epitope of carbamazepine is present in their sera.

Carbamazepine↗
PubMed1992

Effects of adrenergic blockers on central nervous system-mediated hyperglycemia in fed rats.

We studied the effect of adrenergic blockade on hepatic venous hyperglycemia and the activation of a hepatic glycogenolytic enzyme, phosphorylase-a, in response to cerebral cholinergic activation. Neostigmine was injected into the third cerebral ventricle of bilaterally adrenodemedullectomized (ADMX) rats, while somatostatin and insulin were administered intravenously. Hepatic venous plasma glucose concentrations and hepatic phosphorylase-a activity were measured. Intracerebroventricular injection of neostigmine (5 x 10(-8) mol) caused increases in hepatic venous glucose concentrations and hepatic phosphorylase-a activity. Both of these changes were prevented by intraperitoneal (IB) pretreatment with phentolamine (5 x 10(-7), 1 x 10(-6) mol) without the intervention of insulin secretion, but not by pretreatment with the alpha-adrenoreceptor antagonist phenoxybenzamine (1 x 10(-6) mol), the beta-adrenoreceptor antagonist propranolol (1 x 10(-6) mol), the alpha 1-antagonists prazosin or bunazosin (1 x 10(-6) mol), the alpha 2-antagonist yohimbine (1 x 10(-6) mol), or prazosin (5 x 10(-7) mol) plus yohimbine (5 x 10(-7) mol). These results suggest that phentolamine prevented brain-mediated hepatic glycogenolysis by a mechanism that may not be classified pharmacologically as involving either alpha 1- or alpha 2-receptors.

Adrenalectomy↗
PubMed1992

Primary intracerebral malignant lymphoma associated with different histological types of carcinoma: report of two cases.

Two rare cases with histologically proven multiple primary neoplasms are described: an association of intracerebral malignant lymphoma with hepatocellular carcinoma in one case and with squamous cell carcinoma of the uterine cervix in the other. Therapeutic problems pertinent to the coexistence of primary intracerebral malignant lymphoma and neoplasms of a different histological type are discussed.

Aged↗
PubMed1992

Endosalpingiosis in association with ovarian surface papillary tumor of borderline malignancy.

A 40-year-old woman underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, pelvic/paraaortic lymphadenectomy, and omentectomy for Stage IA ovarian surface papillary tumor of borderline malignancy. Microscopic examination revealed endosalpingiosis of ovaries, the peritoneum of uterus, pelvic lymph nodes, and omentum. There was no evidence of disseminated peritoneal malignancy. The several proposed theories of the pathogenesis of endosalpingiosis are reviewed, but that involving metaplasia of the multipotential peritoneal cells is presented as the most acceptable.

Adult↗
PubMed1992

Three new species of the genus Peptostreptococcus isolated from humans: Peptostreptococcus vaginalis sp. nov., Peptostreptococcus lacrimalis sp. nov., and Peptostreptococcus lactolyticus sp. nov.

We describe three new species of the genus Peptostreptococcus which were isolated from human specimens and were tentatively identified as Peptostreptococcus prevotii. These three organisms were not homologous with previously described type strains of the genus Peptostreptococcus. A total of 12 strains that were identified biochemically as P. prevotii were divided into five independent DNA similarity groups; 10 of these strains were divided into three similarity groups which exhibited significant phenotypic differences from previously described species. Therefore, we propose the following new species: Peptostreptococcus vaginalis for group 1 strains, Peptostreptococcus lacrimalis for group 2 strains, and Peptostreptococcus lactolyticus for group 3 strains. The type strain of P. vaginalis is strain GIFU 12669 (= JCM 8138), the type strain of P. lacrimalis is strain GIFU 7667 (= JCM 8139), and the type strain of P. lactolyticus is strain GIFU 8586 (= JCM 8140).

Bacterial Typing Techniques↗
PubMed1992

Dying back type axonal degeneration of sensory nerve terminals in muscle spindles of the gracile axonal dystrophy (GAD) mutant mouse.

A disorder of the gracile axonal dystrophy (GAD) mutant mouse is characterized by a neuromuscular disease with sensory ataxia (detectable 30 days after birth) and paresis of the hindlimbs (detectable at 80 days). In the sensory ataxia stage, histological study of the primary sensory system shows that, in addition to the lesions in the central nervous system, peripherally projecting axons have also started to degenerate at their distal ends in muscle spindles. Although the structure of Ia fibre endings appear normal until 15 days after birth, initial changes in the annulo-spiral structure are detected around the 20th day by a degeneration of the terminal axons. Degeneration then progressed proximally and the secondary endings also start to degenerate. Neuron cell bodies located in the dorsal root ganglia are morphologically intact until the later stages. Chronological studies indicate that, although axonal degeneration progresses throughout life, it is accentuated during the rapid somatic growth period. Around 50 days of age, transient regeneration takes place at axonal endings when somatic growth has attained a plateau. Such primary sensory endings tend to be restored by fine, multiple axons which gain access to the intrafusal fibres through the original endoneurial tubes. Ultrastructural observations at the fully affected stage show intrafusal muscle fibres lying scattered within spindles due to loss of the fine network of inner capsule layers and an almost complete loss of sensory endings from the surface of intrafusal muscle fibres. These results indicate that this mutant mouse is a useful model for naturally occurring 'dying back' type axonal degeneration or 'central and peripheral distal axonopathies', and would provide significant information about the complete evolution of the pathological processes involved.

Animals↗
PubMed1992

Phylogeny of regulatory regions of vertebrate tyrosinase genes.

Highly homologous DNA elements were found to be shared by the upstream regions of the mouse tyrosinase and tyrosinase related protein (TRP-1) genes. Several nuclear proteins were shown to bind to both of these upstream regions. Shared homologous DNA elements were also found in the 5' flanking sequences of Japanese quail and snapping turtle tyrosinase genes. Shared homologous nucleotide sequences were found to be scattered like an archipelago in the 5' upstream regions of mouse and human tyrosinase genes. Comparisons between Japanese quail and snapping turtle tyrosinase genes gave similar results. On the contrary, mammalian (mouse and human) and nonmammalian (quail and snapping turtle) tyrosinase genes did not show significant homology in their 5' upstream regions. In contrast, coding sequences in the first exons of vertebrate tyrosinase genes and their deduced amino acid sequences were found to be highly conserved except for their putative leader sequence-coding regions.

Amino Acid Sequence↗
PubMed1992

Conserved regulatory mechanisms of tyrosinase genes in mice and humans.

In vertebrates, melanin production is restricted to pigment cells. This cell type-specific melanogenesis is considered to involve cell type-specific expression of the tyrosinase gene. Recently, there have been several reports that sequences in the 5' flanking region of the mouse tyrosinase gene are responsible for cell type-specific expression of the transgene in mice. As the first step in the study of the evolution of the regulatory mechanisms for tyrosinase gene function in vertebrates, we constructed a fused gene, hg-Tyrs-J, which includes a 1.0-kb 5' flanking sequence of the human tyrosinase gene fused with mouse tyrosinase cDNA. By introducing the fused gene into fertilized eggs of albino mice, we obtained two mice that exhibited pigmentation in the skin and eyes and established a transgenic line from one of them. Further analyses revealed that the transgene was expressed cell type-specifically in these transgenic mice. We conclude, therefore, that the 1.0 kb 5' upstream region of the human tyrosinase gene contains conserved cis-elements essential for cell type-specific expression of the tyrosinase genes in mice and humans. Results of our study may provide a clue to elucidate the evolutionary process of regulatory mechanisms of the tyrosinase gene.

Animals↗
PubMed1992

[Rapid and direct detection of Mycobacterium tuberculosis complex and mycobacteria in sputum by advanced method, PCR].

We developed two PCR methods, which amplify bovine tuberculous MPB70 gene and mycobacterial 16S rRNA gene, for detection of tubercle bacilli and mycobacteria in sputum, respectively. Among 27 Mycobacterium species and 57 species of 30 genuses other than Mycobacterium, only M. tuberculosis (TB) complex, i.e., M. tuberculosis, M. bovis, M. africanum, M. microti showed DNA amplification by PCR for MPB70, and amplification of 16S rRNA gene were observed specific in Mycobacterium species. A combination of these PCR abilities were available to differentiate the TB complex and nontuberculous mycobacteria (NTM). We investigated the correlation between these methods and conventional methods with 311 sputa that were suspected mycobacteriosis. The PCR method could detect 12 cases of TB complex and 4 cases of NTM in 17 specimens, which were positive by conventional methods, but could not for one specimen. Among 294 specimens that were negative with conventional methods, the PCR method detected 13 and 8 cases of TB complex and NTM, respectively. These results were confirmed by commercial tuberculous specific DNA probe or investigation of the clinical background of the patients. On the other hand, 273 specimens showed negative result either PCR nor conventional methods. The PCR method did not detect tuberculous DNA in normal 197 sputa, which were not suspected mycobacteriosis. These results indicate that each one of these PCR methods is highly specific to TB complex or Mycobacterium species. We concluded that these PCR methods are useful and advanced methods for rapid and direct detection of tuberculosis and mycobacteriosis.

DNA, Bacterial↗
PubMed1992

Mechanism of intrahippocampal neostigmine-induced hyperglycemia in fed rats.

We previously reported that the injection of neostigmine, an acetylcholine esterase inhibitor, into the dorsal hippocampus produced hepatic venous plasma hyperglycemia associated with an increase of epinephrine and glucagon in anesthetized fed rats. To evaluate the relative contribution of these glucoregulatory hormones and the nervous system to the net hyperglycemic response, we unilaterally injected neostigmine (5 x 10(-8) mol) into the dorsal hippocampus in the following groups of rats: intact rats with bilateral adrenalectomy to eliminate the action of epinephrine, and rats receiving a constant infusion of somatostatin and insulin to prevent the glucagon response and to maintain the basal insulin level. Hepatic venous plasma levels of glucose, immunoreactive glucagon, immunoreactive insulin, epinephrine, and norepinephrine were determined. The area under the glucose curve during the 120-min period following the injection of neostigmine was compared between groups. The areas under the glucose curve for rats receiving somatostatin and insulin, adrenalectomy rats, and adrenalectomy rats receiving somatostatin and insulin were, respectively, 82, 31, and 61% of that for intact rats. The fashion of hippocampal stimulated hyperglycemia with neostigmine was similar to that after injection of neostigmine into the third cerebral ventricle. Therefore, we investigated hyperglycemia in rats with lesions of ventromedial hypothalamus and found that the response to hippocampal neostigmine was significantly inhibited by the hypothalamic lesion. These findings suggest that the glucoregulatory hippocampal activity evoked by neostigmine may be transmitted to peripheral organs via the ventromedial hypothalamus.

Animals↗
PubMed1992

Case report of desquamative interstitial pneumonia: documentation of preserved pulmonary function after twelve clinical relapses.

We describe a case of desquamative interstitial pneumonia diagnosed in a 25-year-old woman who relapsed 12 times during a 20-year follow-up period. In each relapse, the involved sites were different and the patient ultimately recovered without resultant pulmonary ventilatory defects. Bronchoalveolar lavage performed during the 12th relapse revealed a remarkable increase in the number of total cells and showed a low CD4+/CD8+ ratio in the lymphocyte subset.

Adult↗
PubMed1992

A case of cyclophosphamide-induced interstitial pneumonitis diagnosed by bronchoalveolar lavage.

A successfully treated case of cyclophosphamide pneumonitis, which developed during treatment for a leukemic phase of B-cell non-Hodgkin's lymphoma, is documented. Subtyping of lymphocytes in the peripheral blood and the bronchoalveolar lavage fluid easily excluded a possible diagnosis of pulmonary involvement of lymphoma. Bronchoalveolar lavage is a useful approach to determine the correct etiology of pneumonitis.

Aged↗