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Biomedical subjects

T Toda

Publications and source records attributed to T Toda.

At least 289 records · Page 16Linked to original sources
PubMed1989

The fission yeast dis2+ gene required for chromosome disjoining encodes one of two putative type 1 protein phosphatases.

S. pombe dis mutants block mitotic chromosome disjunction in a manner reminiscent of aneuploidy formation, and belong to three distinct genes, dis1-dis3. We cloned two independent genomic DNAs that complemented both the cold-sensitive and caffeine-hypersensitive phenotype of dis2-11. These genes, dis2+ and a suppressor sds21+, encode proteins (calculated MW 37,000) with similar predicted amino acid sequences. dis2+ and sds21+ have overlapping functions, and disruptants are lethal only when both genes are disrupted. The gene products identified by anti-dis2 serum are enriched in nuclei. By hybridization, we obtained two cDNA clones from mouse and one genomic clone from S. cerevisiae; the latter complements S. pombe dis2-11. These dis2+ and similar polypeptides of yeasts and mouse are found to be highly homologous (75%-90% identical) to rabbit protein phosphatase 1. The implications of these findings are discussed with regard to mitotic control.

Alleles↗
PubMed1989

An immunohistochemical study on the innervation of SP-IR nerves in the cerebral arteries of the bent-winged bat.

The overall distribution of substance P (SP) immunoreactive (IR) nerves surrounding the cerebral arteries of the bent-winged bat were investigated immunohistochemically. In this microchiropteran species, the walls from the vertebral artery to the caudal part of the basilar artery have considerably well-developed plexuses of SP-IR nerves, whereas no demonstrable SP-IR fibers were found in the rostral part of the basilar artery, and in more rostrally located arteries the nerve supply was very sparse or occasionally lacking. This innervation pattern has not yet been established for the cerebral arterial systems of other mammals that have been studied under normal conditions, but it is very similar to the pattern of SP-IR innervation observed in the guinea pig and cat of which the trigeminal ganglia have been destroyed. From the combination of this and other immunohistochemical findings, it is suggested that SP-IR nerves innervating the vertebral and basilar arteries of the bent-winged bat originate from the upper cervical dorsal root ganglia (DRG) and enter the cranial cavity along the vertebral artery and through the meninges.

Animals↗
PubMed1989

Immature renal tissue in inguinal canal.

A 3-year-old boy underwent an operation for a right undescended testis. A small, elastic, hard mass attached loosely to the spermatic cord was noted in the inguinal canal away from the testis and epididymis. Pathological examination of this mass revealed mesonephric remnant tissue.

Abdominal Neoplasms↗
PubMed1989

Systemic distribution of 14C-labeled formaldehyde applied in the root canal following pulpectomy.

The systemic distribution of 14C-labeled formaldehyde which had been placed in the root canals of the canines of cats following pulpectomies was studied using liquid scintillation counting and wholebody autoradiographic technique. Radioactive 14C which had been placed in the canals was found in the plasma 30 min after the root canal procedure. The recovery of systemic 14C radioactivity increased with time. In addition, it seemed that approximately 3% of the dose placed in the teeth was excreted in the urine within 36 h. Whole-body autoradiograms indicated extensive concentration of 14C radioactivity in tissues other than those analyzed with the liquid scintillation technique.

Animals↗
PubMed1989

A maxillary central incisor having two root canals geminated with a supernumerary tooth.

This article reports the treatment of a maxillary left central incisor geminated with a supernumerary tooth. A patient having labial swelling around the maxillary incisors was referred to this hospital for diagnosis and endodontic treatment of the maxillary left central incisor. Clinical and radiographic examinations revealed a tooth having two roots and three canals. Examination of a rubber base impression of the cleaned canals showed there was neither perforation of, nor communication with, the radicular groove in the tooth.

Child↗
PubMed1989

Essential roles of the RNA polymerase I largest subunit and DNA topoisomerases in the formation of fission yeast nucleolus.

A temperature-sensitive lethal mutant nuc1-632 of Schizosaccharomyces pombe shows marked reduction in macromolecular synthesis and a defective nuclear phenotype with an aberrant nucleolus, indicating a structural role of the nuc1+ gene product in nucleolar organization. We cloned the nuc1+ gene by transformation and found that it appears to encode the largest subunit of RNA polymerase I. We raised antisera against nuc1+ fusion polypeptides and detected a polypeptide (approximately 190 kD and 2 x 10(4) copies/cell) in the S. pombe nuclear fraction. By immunofluorescence microscopy, anti-nuc1+ antibody revealed intense staining at a particular nuclear domain previously defined as the nucleolus. The nucleolar immunofluorescence by anti-nuc1+ was faded in nuc1-632 at restrictive temperature and dramatically diminished in the absence of DNA topoisomerases I and II. Thus active RNA polymerase I appears to be required for the formation of the nucleolus as its major component, and DNA topoisomerases appear to be required for the folding of rDNA and RNA polymerase I molecules into the functional organization of nucleolar genes.

Amino Acid Sequence↗
PubMed1989

Enhancement of both intracellular uptake and antitumor action of cisplatinum on human neuroblastoma cells by encapsulation in liposomes.

Phospholipid vesicles (phosphatidylcholine:phosphatidylserine:cholesterol = 6:2:3 in molar ratio) with a small unilamellar structure were used as drug carriers for introducing cis-diamminedichloroplatinum (CDDP) into human neuroblastoma cells, IMR-32, GOTO, Nagai, and TGW. DNA synthesis of IMR-32 cells among the human neuroblastoma cell lines was inhibited most strongly by CDDP-liposomes. CDDP-liposomes dose-dependently inhibited the DNA synthesis of IMR-32 in a similar fashion to that observed with free CDDP, but the drug concentration required to induce 50% inhibition of DNA synthesis for CDDP-liposomes (IC50: 0.7 micrograms CDDP/ml) was 1/3 of the IC50 for free CDDP (2.0 micrograms CDDP/ml). In support of the marked growth-inhibitory action of CDDP-liposomes, the intracellular incorporation rate of CDDP-liposomes was 3-fold higher when liposomes were used as carriers than when free CDDP was directly applied. CDDP-liposomes showed a stronger growth inhibition on IMR-32 cells at a high cell density than at a low density in culture. CDDP-liposomes were rapidly incorporated by IMR-32 cells within 5 min, resulting in the inhibition of DNA synthesis to 40% of the control. Swiss albino mouse 3T3 cells were less inhibited by CDDP-liposomes than by free CDDP, suggesting that encapsulation of CDDP in liposomes decreases cytotoxicity to normal cells.

Biological Transport↗
PubMed1989

[An autopsy case of AIDS with disseminated cytomegalovirus infection and neurological disturbance].

We report a case of acquired immunodeficiency syndrome (AIDS) complicated by disseminated CMV infection and neurological disturbance. A 21 years old male with hemophilia A was diagnosed as having AIDS in Feb. 1986 because of interstitial pneumonia and esophageal candidiasis. Since Jan. 1987 he had complained of hypesthesia in the legs. On Mar. 14 he was admitted due to diarrhea. The laboratory data revealed that WBC was 4,000/microliters including 29% of lymphocytes, 1.6% of OKT4+-, 71.6% of OKT8+-lymphocytes, T4/T8 ratio 0.02 and positive HIV antibody and HTLV-1 antibody. After the admission, sensory disturbance exacerbated to complicate paraplegia. He developed acute hepatitis associated with leukopenia, thrombocytopenia, pneumonia and melena, and eventually died on May 29. The autopsy findings disclosed CMV infection in the lungs, colons, and adrenal glands, suggesting that the primary cause of death was adrenal insufficiency. Degeneration of cerebro-spinal nerve cells and peripheral neuritis were thought to result from direct HIV infection to the nervous system.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[A case report of giant cell granuloma of the jaw].

A giant cell granuloma of the mandible seen in a 16 month-old boy was reported. Histopathology showed that the lesion consisted basically of granulation tissue with multinucleated giant cells, spindle-shaped and polygonal stromal cells. No atypia was seen in giant cells or stromal cells. Electron microscopic examination revealed that multinucleated giant cells possessed microvillous structure on their cytoplasm and were rich in organelles such as endoplasmic reticulum, mitochondria and dense bodies. Stromal cells consisted of macrophage-like and fibroblastic cells. Immunohistochemical examination demonstrated a large number of giant cells and stromal cells that were strongly positive for the antibodies of alpha-1-antitrypsin and alpha-1-antichymotrypsin. These morphological findings suggest that macrophage-like stromal cells are the precursors to giant cells.

Giant Cells↗
PubMed1989

[The evaluation of ultrasonic oocyte collection techniques for IVF-ET--comparing the transabdominal and transvaginal methods].

In order to evaluate the effectiveness and safety of ultrasonic oocyte collection for IVF-ET, a comparative study was performed on the results of IVF-ET by the transabdominal and transvaginal methods in 145 cycles of 51 patients. The oocyte collection rate for the transvaginal method was significantly higher than that for the transabdominal method (77.1% vs. 68.7% per follicle, p less than 0.01). The majority of the oocytes were collected in three follicular flushings. The fertilization rate for oocytes collected by the transabdominal method was significantly higher than that for those collected by the transvaginal method in cases of tubal damage and endometriosis (81.1% vs. 65.6% per oocyte, p less than 0.01). There was no significant difference between the signs of complications seen with the two methods. Six successful pregnancies were obtained by IVF-ET in our hospital (4 cases by the transabdominal method, and 2 cases by the transvaginal method). Two of these cases have already delivered full term healthy male infants. In conclusion, these results indicate that ultrasonic oocyte collection has been established as the most effective method for IVF-ET by means of either the transabdominal or the transvaginal methods.

Adult↗
PubMed1989

Promotive effect of elastase on regression of aortic atherosclerosis in cholesterol-fed quails.

In order to test the anti-atherosclerotic function of elastase, 44 Japanese quails, 40 d of age, were used in this study. An atherogenic diet contained 15% corn oil and 2% cholesterol. Elaszym was orally administered at a dose of 6,000 EL units per kg body weight 3 times a week for 3 months. After 3 months feeding the atherogenic diet was discontinued. Moderate hypercholesterolemia and marked lipid-rich aortic lesions were noted in the group which was fed the atherogenic diet for 3 months. The thickened intima was composed of fibroblasts and alpha-1-anti-trypsin, S-100 protein, calmodulin and elastase were strongly demonstrated. Withdrawal of the atherogenic diet resulted in marked improvement of the serum cholesterol level, and slight reduction of the degree of the intimal thickening of the thoracic aorta. Elastase treatment after the withdrawal of atherogenic diet induced significant regression of the aortic lesions of the thoracic aorta. These results suggest that Elaszym possesses the promotive effect on regression of atherosclerotic lesions.

Animals↗
PubMed1988

An improved method of high-voltage isoelectric focusing on cellulose acetate membranes.

An apparatus and the procedure for cellulose acetate isoelectric focusing were refined and optimized for routine use in clinical laboratories. The space in the electrophoretic chamber was minimized to maintain high humidity during the run. The water content of the thin cellulose acetate membranes in the chamber was well controlled during isoelectric focusing and the effect of atmospheric carbon dioxide was also excluded. The temperature of the membranes was kept below 2 degrees C, even under conditions of high electric field strength for faster isoelectric focusing of high-molecular-weight proteins. No special training was required for technicians in clinical laboratories to obtain reproducible isoelectric profiles of human serum proteins.

Blood Proteins↗
PubMed1988

Cold-sensitive and caffeine-supersensitive mutants of the Schizosaccharomyces pombe dis genes implicated in sister chromatid separation during mitosis.

We isolated novel classes of Schizosaccharomyces pombe cold-sensitive dis mutants that block mitotic chromosome separation (nine mapped in the dis1 gene and one each in the dis2 and dis3 genes). Defective phenotype at restrictive temperature is similar among the mutants; the chromosomes condense and anomalously move to the cell ends in the absence of their disjoining so that they are unequally distributed at the two cell ends. Synchronous culture analyses indicate that the cells can enter into mitosis at normal timing but become lethal during mitosis. In comparison with the wild-type mitosis, defects are found in the early spindle structure, the mitotic chromosome structure, the poleward chromosome movement by the spindle elongation and the telophase spindle degradation. The dis mutants lose at permissive temperature an artificial minichromosome at higher rates than occur in the wild type. We found that all the dis mutants isolated are supersensitive to caffeine at permissive temperature. Furthermore, the mutant cells in the presence of caffeine produce a phenotype similar to that obtained at restrictive temperature. We suggest that the dis genes are required for the sister chromatid separation at the time of mitosis and that caffeine might affect the dis gene expression. We cloned, in addition to the dis2+ and dis3+ genes, multicopy extragenic suppressor sequences which complement dis1 and dis2 mutations. A complex regulatory system may exist for the execution of the dis+ gene functions.

Caffeine↗
PubMed1988

SCH9, a gene of Saccharomyces cerevisiae that encodes a protein distinct from, but functionally and structurally related to, cAMP-dependent protein kinase catalytic subunits.

A new gene, SCH9, was isolated from Saccharomyces cerevisiae by its ability to complement a cdc25ts mutation. Sequence analysis indicates that it encodes a 90,000-dalton protein with a carboxy-terminal domain homologous to yeast and mammalian cAMP-dependent protein kinase catalytic subunits. In addition to suppressing loss of CDC25 function, multicopy plasmids containing SCH9 suppress the growth defects of strains lacking the RAS genes, the CYR1 gene, which encodes adenylyl cyclase, and the TPK genes, which encode the cAMP-dependent protein kinase catalytic subunits. Cells lacking SCH9 grow slowly and have a prolonged G1 phase of the cell cycle. This defect is suppressed by activation of the cAMP effector pathway. We propose that SCH9 encodes a protein kinase that is part of a growth control pathway which is at least partially redundant with the cAMP pathway.

Amino Acid Sequence↗