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Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 793 records · Page 44Linked to original sources
PubMedDate not supplied

The sugar beet mitochondrial gene for the ATPase alpha-subunit: sequence, transcription and rearrangements in cytoplasmic male-sterile plants.

We have characterized the mitochondrial atpA (the alpha subunit of F1-ATPase) gene from male-fertile cytoplasm (cv TK81-0) of sugar beet. The gene is 1518-bp long and encodes a polypeptide of 506 amino acids. The atpA mRNA sequence is modified by three C-to-U RNA editing events, all of which alter the encoded protein sequences. In order to examine the genome organization of the atpA locus in cytoplasmic male-sterile (CMS) sugar beet, atpA-containing clones were isolated from Owen CMS (TK81-MS) and a different source of CMS [I-12CMS(2)] cytoplasm respectively. The sequences of the atpA coding region from TK81-MS and I-12CMS(2) are identical to each other and to the corresponding TK81-0 sequence. However, the TK81-0 and TK81-MS loci diverge completely 47 bp upstream of the initiation codon, resulting in different 5' transcript termini for the two genes. On the other hand, the point of divergence between the TK81-0 and I-12CMS(2) atpA genes was found to occur after 393 bp 3' to the TAA stop codon. Our results also show the 3'-flanking sequences of I-12CMS(2) atpA to be present elsewhere in the mitochondrial genomes of TK81-0, TK81-MS and I-12CMS(2), suggesting the possible involvement of these repeated DNA elements in the sequence rearrangements.

Adenosine Triphosphatases↗
PubMedDate not supplied

Cyclin D1 overexpression in invasive breast cancers: correlation with cyclin-dependent kinase 4 and oestrogen receptor overexpression, and lack of correlation with mitotic activity.

BACKGROUND: Cyclin D1 (CCND1) and its catalytic partner cyclin-dependent kinase 4 (cdk4) are known to play important roles in the G1/S check point of the cell cycle, and CCND1 overexpression has been reported to correlate with progression and prognosis of breast cancers. Oestrogen receptor (ER) levels determine the proliferative response to oestrogen by regulating binding. It has been postulated that CCNDI and cdk4 exert effects on mammary carcinogenesis in co-operation with ER. PATIENTS AND METHODS: CCND1 and cdk4 overexpression in 117 breast cancer cases with long-term follow-up were investigated by means of immunohistochemistry and differential polymerase chain reaction (PCR), using formalin-fixed and paraffin-embedded samples, and compared with ER status and mitotic indices. Additional Western blotting and reverse transcription (RT)/PCR/Southern blot hybridization were performed for 4 breast cancer cell lines and 15 fresh-frozen breast cancer samples to confirm CCND1 and cdk4 data. RESULTS: Immunohistochemically 27 cases were CCND1-positive (23.0%), and CCND1 amplification was evident in 21 (21/86; 24.4%). The two methods in combination demonstrated 37 cases (31.6%) to be positive for CCND1 overexpression. Western blotting revealed 60% of samples of fresh tissue to overexpress CCND1, corresponding well with the results of RT-PCR. There was thus a strong discrepancy between results for paraffin block and fresh samples, probably because of the short life of CCND1. In the case of cdk4, the respective percentages for positive cases were 54.7% and 73%. CCND1 and cdk4 overexpression (P < 0.0001), and CCND1 and ER positivity (P = 0.0128) correlated. In addition, samples overexpressing CCND1, cdk4 and ER tended to have slightly lower proliferative activity than samples where these were absent. However, no association with clinicopathological parameters was evident. cdk4 overexpression had no linkage with ER status or clinicopathological status. Neither CCND1 nor cdk4 expression affected prognosis. CONCLUSION: CCND1 overexpression does not correlate with cancer progression or prognosis or with mitotic activity. The results may suggest that an excess accumulation of CCND1 in breast cancer cells tends to suppress entry into the S phase of the cell cycle.

Blotting, Western↗
PubMedDate not supplied

Preparation, 195Pt NMR spectra and biological activity of platinum (IV) complexes with dipeptides.

Three dipeptide complexes of the form K[Pt(IV) (dipep) Cl(OH)2] and four dipeptide complexes of the form K[Pt(IV)-(Hdipep)Cl2(OH)2] were newly prepared. The 195 Pt NMR peak of the K[Pt(IV) (dipep)Cl(OH)2] complexes appeared at about 1200 ppm and these chemical shifts were about 3150 ppm downfield compared with those of the K[Pt(II) (dipep) Cl] complexes. The chemical shifts of the K[Pt(IV) (Hdipep) Cl2 (OH)2] complexes were at about 900 ppm, i.e., about 3050 ppm downfield compared with those of the K[Pt(II) (Hdipep)Cl] complexes. The H[Pt(IV) (Hdigly) Cl2(OH)2] and K[Pt(IV) (Hdigly) Cl2(OH)2] complexes inhibited the growth of C. albicans at a more diluted concentration than cisplatin at 1 microgram/ml, but the platinum complexes only weakly inhibited the growth of these cells compared with the cisplatin-inhibited growth of Meth-A and Hep-2 cells at 10 micrograms/ml. These results suggested that the platinum complexes selectively inhibited the growth of fungal cells.

Anti-Bacterial Agents↗
PubMedDate not supplied

Biological and immunogenic properties of rabies virus glycoprotein expressed by canine herpesvirus vector.

In order to evaluate whether canine herpesvirus (CHV) could be used as a live vector for the expression of heterologous immunogenes, we constructed a recombinant canine herpesvirus (CHV) expressing glycoprotein (G protein) of rabies virus (RV). The gene of G protein was inserted within the thymidine kinase gene of CHV YP11mu strain under the control of the human cytomegalovirus immediate early promoter. The G protein expressed by the recombinant CHV was processed and transported to the cell surface as in RV infected cells, and showed the same biological activities such as low pH dependent cell fusion and hemadsorption. The antigenic authenticity of the recombinant G protein was confirmed by a panel of monoclonal antibodies specific for G protein. Dogs inoculated intransally with the recombinant CHV produced higher titres of virus neutralizing antibodies against RV than those inoculated with a commercial, inactivated rabies vaccine. These results suggest that the CHV recombinant expressing G protein can be used as a vaccine to control canine rabies and that CHV may be useful as a vector to develop live recombinant against other infectious diseases in dogs.

Animals↗
PubMedDate not supplied

Comparison of [123I]metaiodobenzylguanidine kinetics with heart rate variability and plasma norepinephrine level.

BACKGROUND: [123I]Metaiodobenzylguanidine (MIBG) imaging has been used to assess cardiac sympathetic nerve abnormalities. We evaluated the clinical significance of myocardial MIBG imaging as a measure of cardiac sympathetic nervous system function by comparing it to heart rate variability and plasma norepinephrine level. METHODS AND RESULTS: In 211 subjects, we analyzed heart rate variability with 24-hour electrocardiography, performed scintigraphy with MIBG, and measured plasma norepinephrine levels. Time and frequency domain measures of heart rate variability were calculated with the Marquette heart rate variability program (Marquette Electronics, Milwaukee, Wis.). Early and late myocardial MIBG uptakes were measured at 15 and 150 minutes after injection, respectively. MIBG clearance rate from the heart and heart-to-lung and heart-to-mediastinum ratios of MIBG activities were calculated. On the whole, heart rate variability, including low-frequency power, correlated positively, but modestly so, with late MIBG uptake and negatively with MIBG clearance rate. The plasma norepinephrine level correlated negatively with late MIBG uptake and with heart rate variability, including low-frequency power, and positively with MIBG clearance rate. Similar correlations were also observed in patient subgroups with coronary artery disease, diabetes mellitus, and renal failure, but these correlations were weak (R2 < 0.5). CONCLUSIONS: Increased cardiac sympathetic nervous system activity may be associated with increased myocardial MIBG clearance and decreased heart rate variability, including low-frequency power. Because these associations were not strong, however, the combination of heart rate variability with MIBG may allow an interactive assessment of the cardiac autonomic nervous system.

3-Iodobenzylguanidine↗
PubMedDate not supplied

A new mutant rat with turning behavior (Tur).

A new rat mutant with abnormal behavior has been found in a closed colony of Slc: SD. The affected rats turned around after their own tails beginning 4-5 weeks after birth, in response to extroceptive stimuli, such as sound or vibration. The behavior was more pronounced in younger animals. On gross observation, no alteration was found in the cerebrum, cerebellum, or anterior, posterior, or lateral semicircular canals. Light microscopic examination revealed no abnormality in the cerebrum or cerebellum. The trait was controlled by an autosomal dominant gene with incomplete penetrance (78.0%) when transferred to the WKY genetic strain background. It was named "turning" with the gene symbol Tur. A congenic strain was established, which was designated WKY/Eis-Tur.

Animals↗
PubMedDate not supplied

A new mutant rat with hyperbilirubinuria (hyb).

We have discovered mutant rats with hyperbilirubinuria at the laboratories of Eisai Co., Ltd., Gifu, Japan, and established a new inbred mutant strain, which was designated Eisai Hyperbilirubinuria Rat (EHBR/Eis). They show jaundice immediately after birth, and direct or conjugated hyperbilirubinemia throughout their life. The phenotypes are controlled by a single autosomal recessive gene, hyb with full penetrance. Affected homozygous males seem to have full reproductive capacity. On the other hand, the litter size of hyb/hyb females is significantly reduced at second parturition compared with that at first one. In order to maintain the strain efficiently and to produce both affected (hyb/hyb) and normal control (hyb/+) offspring at the same time, we have mainly been mating hyb/hyb males with hyb/+ females in establishing the inbred strain. We also report here the allele distribution of the EHBR/Eis strain.

Animals↗