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Biomedical subjects

C Miyazaki

Publications and source records attributed to C Miyazaki.

At least 73 records · Page 4Linked to original sources
PubMed1991

Identification of eleven single-strand initiation sequences (ssi) for priming of DNA replication in the F, R6K, R100 and ColE2 plasmids.

Based on the ability to complement the poor growth of an M13 phage derivative lacking the complementary strand origin, eleven single-strand initiation sequences (ssi) for DNA replication are identified in the F, R6K, R100 and ColE2 plasmids. Six of them were from F, two from near the gamma and alpha origins (ori) of R6K, two from the vicinity of the basic replicon of R100 and one from near the ori of ColE2. They can be classified into two groups based on the morphology of the plaques and the length of nucleotide (nt) sequences required for ssi activity; one group that gives rise to larger and clearer plaques and can be reduced to nearly 100 nt (seven out of eleven), and another that generates smaller and less clear plaques and requires more than 200 nt for full activity (four out of eleven). Sequence homology is detected among some members from both groups. The possible biological roles of the ssi are discussed.

Bacteriocin Plasmids↗
PubMed1991

Introduction and transposition of the maize transposable element Ac in rice (Oryza sativa L.).

To develop a transposon tagging system in an important cereal plant, rice (Oryza sativa L.), the maize transposable element Ac (Activator) was introduced into rice protoplasts by electroporation. We employed a phenotypic assay for excision of Ac from the selectable hph gene encoding resistance to hygromycin B. Southern blot analysis of hygromycin B-resistant calli showed that the Ac element can transpose from the introduced hph gene into the rice chromosomes. Sequence analysis of several Ac excision sites in the hph genes revealed sequence alterations characteristic of the excision sites of this plant transposable element. The Ac element appears to be active during development of transgenic rice plants from calli. Moreover, hybridization patterns of different leaves from the same plant indicated that some Ac elements are stable whereas others are able to transpose further during development of leaves. The results indicate that the introduced Ac element can transpose efficiently in transgenic rice plants.

Base Sequence↗
PubMed1991

Aseptic meningitis in children: correlation between fever and interferon-gamma level.

We studied the correlation between interleukin-1 beta (IL-1 beta), tumour necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) in cerebrospinal fluid (CSF) and clinical/laboratory findings in children with aseptic meningitis. In 19/27 patients (70%), the CSF IFN level was high at initial diagnosis, and reduced to a low or undetectable level during the convalescent phase (5-14 days later) of the disease. There were no differences in IL-1 beta and TNF-alpha levels between the acute and convalescent phase of the patients. The serum IFN-gamma levels in the patients, which were simultaneously examined were undetectable in the acute phase. When we compared the clinical/laboratory findings between the 29 patients with detectable CSF IFN-gamma level and the 21 patients with an undetectable CSF IFN-gamma level in the acute phase, the former demonstrated higher body temperature (P less than 0.01), and higher cell number and protein level in the CSF (P less than 0.05) than the latter. On the other hand, there were no significant differences in the duration of meningeal signs, the titre of C-reactive protein, and the peripheral leucocyte count between the two groups. By the Spearman's rank sum test, the CSF IFN-gamma levels correlated more definitively with the severity of febrile episode (maximal body temperature, duration of fever and body temperature at the first lumbar tap), and the cell number and protein level in the CSF. These results suggest that IFN-gamma produced in the inflamed intrathecal space may be associated with the pathogenesis of aseptic meningitis, especially the production of fever.

Child↗
PubMed1990

Supraventricular tachycardia in acquired rubella infection: a case report.

A 6-year-old boy developed supraventricular tachycardia nine days after onset of the exanthem of clinical rubella. The diagnosis of rubella virus infection was confirmed serologically. Except in the neonatal period, only eight cases of cardiac involvement in acquired rubella infection have been previously reported. During epidemics, rubella virus infection should be considered in patients who manifest cardiac symptoms and signs of unknown etiology.

Child↗
PubMed1990

Synthesis of valproyl-2-pyrrolidinone and its evaluation as a cognitive drug with the ability to modulate acidic amino acids in the brain.

A new pyrrolidinone derivative, valproyl-2-pyrrolidinone (VP), was synthesized, followed by evaluation as a cognitive drug. VP gave rise to a significant protective effect against cerebral anoxia together with a potent prolongation of latency time for the reversal of scopolamine induced transient disruption of the memory of a passive avoidance response in rats. The quantitative experiment using HPLC demonstrated a significant reduction of hippocampal aspartate (Asp) and glutamate (Glu) following the intraperitoneal administration of VP at a dose of 300 mg/kg.

Administration, Oral↗
PubMed1989

Histiocytic hemophagocytosis in the bone marrow in children with sepsis and disseminated intravascular coagulation.

Two children with systemic E. coli and candidial infections developed disseminated intravascular coagulation (DIC). Bone marrow examination in both cases showed histiocytic hemophagocytosis, consistent with the diagnosis of the hemophagocytic syndrome. Histiocytic hemophagocytosis in the bone marrow, one of the markers of the activated mononuclear phagocyte system, might be common in patients with severe sepsis and DIC, especially in immunodeficiency.

Adolescent↗
PubMed1989

Pulmonary and pleural involvements at initial diagnosis in children with malignant neoplasm.

Seventeen cases of pediatric malignant neoplasm with pulmonary and/or pleural lesions shown by chest radiography at initial diagnosis were reviewed and analyzed. Respiratory symptoms such as dyspnea, tachypnea, and chest pain were observed on admission in approximately one-half of them. The initial chest radiography showed pleural lesions in 7 of the 17, pulmonary lesions in 8, and both pulmonary and pleural lesions in 2. Unilateral or bilateral pleural fluids were observed in all of the seven patients with pleural lesions, and malignant cells were confirmed in the pleural fluid of all patients. The radiographic patterns of the eight patients with pulmonary lesions were solitary nodule in two, multiple nodules in two, diffuse miliary nodules in three, and diffuse honeycomb in one. Histological examination of the pulmonary lesion was performed in six patients at the initial diagnosis or after death, while in the remaining two primary or other metastatic sites were examined. The two patients with both pulmonary and pleural lesions showed multiple nodules or infiltrates with pleural fluid on chest radiography. Increased malignant cells were detected in the pleural fluid of both patients. In all cases, the lesions gradually or rapidly disappeared with multidrug chemotherapy. The review confirms the need for a combination of complete radiographic and pathological analysis at the time of initial diagnosis of malignant neoplasm in children to distinguish other causes such as infectious complications.

Adolescent↗
PubMed1988

Unidirectional replication of plasmid R100.

We isolated a 284 base-pair BamHI fragment of plasmid R100 that supports initiation of replication of a plasmid regardless of the orientation of the fragment. Analysis of the specific radioactivity of restriction fragments from 32P-labeled replication intermediates synthesized in vitro shows that replication of the plasmid carrying the 284 base-pair fragment is unidirectional. The direction of replication depends on the orientation of the fragment present in the plasmid. The 5' ends of the leading-strand DNA formed in the early stage of replication were mapped to a region downstream from the 284 base-pair fragment in the direction of replication. The lagging-strand DNA products were also identified and their 3' ends mapped to unique sites within the 284 base-pair fragment causing unidirectional replication of R100.

Autoradiography↗
PubMed1988

Determination of gamma-aminobutyric acid and associated amino acids in mouse brain by liquid chromatography.

A rapid method is described for the analysis of amino acids containing in mouse brain by high performance liquid chromatography equipped with a fluorescence detector. Pre-column o-phthalaldehyde-2-mercaptoethanol derivatives of the amino acids were injected onto an ODS C-18 column. 5-Amino-n-valeric acid, a non-endogenous amino acid, was used as an internal standard. Separation and elution of amino acid derivatives were achieved by varying the ratio of organic phase by a step gradient. Significant increases in gamma-aminobutyric acid, glutamine and glycine levels in the brain were detected 2 h after injection of 800 mg/kg valproic acid (VPA). A high dose administration of VPA was correlated with Reye's syndrome.

Amino Acids↗
PubMed1986

Characterization of the gene products produced in minicells by pSM1, a derivative of R100.

At least ten polypeptides larger than 6 kilodaltons (K) are produced in minicells from the miniplasmid pSM1 in vivo. pSM1 (5804 bp) is a small derivative of the drug resistance plasmid R100 (ca. 90 kb) and carries the R100 essential replication region as well as some non-essential functions. Cloned restriction fragments of pSM1 and plasmids with deletions within pSM1 sequences were used to assign eight of the ten observed polypeptides to specific coding regions of pSM1. Two of these polypeptides were identified as RepA1 and RepA2, proteins encoded by the essential replication region of pSM1/R100. The nucleotide sequence consisting of 885 bp outside the essential replication region is presented here. This sequence contains an open reading frame, orf4, for a protein 22.9 K in size, and one of the pSM1-encoded polypeptides was identified as the orf4 gene product. Five additional polypeptides were shown to be the products of other open reading frames mapping outside the essential replication region. Specific functions have been assigned to four of these polypeptides and tentatively to the fifth.

Amino Acid Sequence↗
PubMed1985

Reinduction of experimental allergic encephalomyelitis in convalescent Lewis rats with cyclophosphamide.

Experimental allergic encephalomyelitis (EAE) in Lewis rats is an acute, monophasic autoimmune disease, and rats recovering from EAE are generally resistant to active reinduction. However, following immunosuppression with a high dose (100-200 mg/kg) of cyclophosphamide (CY), EAE was reinduced in convalescent rats, irrespective of whether or not they were rechallenged with the encephalitogenic inoculum. Reinduction of EAE was not observed in rats treated with low doses (20 mg/kg or less) of CY. A selective inhibition of suppressor cells during the convalescent stage may be responsible for the reinduction of EAE in Lewis rats.

Animals↗