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Biomedical subjects

Y Oshima

Publications and source records attributed to Y Oshima.

At least 217 records · Page 12Linked to original sources
PubMed1993

Relationship between urinary excretion of fibronectin degradation products and proteinuria in diabetic patients, and their suppression after continuous subcutaneous heparin infusion.

To explore the possibility that the excretion of urinary fibronectin degradation products (U-FnDP) can be an indicator of the progression of diabetic nephropathy, U-FnDP and urinary protein(U-P) were determined in 64 diabetic patients and 11 healthy volunteers. Moreover, to determine whether continuous subcutaneous heparin infusion (CSHI) reduces elevated U-FnDP and U-P in diabetic patients with persistent proteinuria, heparin sodium was administered as a bolus subcutaneous injection of 5000 IU, followed by subcutaneous infusion of 250 IU/kg per 24 h heparin sodium for 7 days. U-FnDP excretion rate elevated proportionally to the degree of U-P. CSHI reduced significantly elevated U-FnDP from 172.68 +/- 15.79 to 100.04 +/- 14.93 micrograms/24 h (P < 0.01) and U-P from 1.76 +/- 0.13 to 1.20 +/- 0.12 g/24 h (P < 0.01). No significant changes in blood pressure and diurnal mean plasma glucose levels were found. APTT was prolonged with a decrease of AT-III activity during the treatment. These findings suggest that U-FnDP can be one of the indicators which reflects the degree of progression of diabetic nephropathy, and that CSHI may be useful for the normalization of elevated U-FnDP and reduction in U-P in diabetic nephropathy.

Adult↗
PubMed1993

Pharmacological properties of beta-amyrin palmitate, a novel centrally acting compound, isolated from Lobelia inflata leaves.

Effects of beta-amyrin palmitate isolated from the leaves of Lobelia inflata were studied on the central nervous system of mice and were compared with those of antidepressant drugs, mianserin and imipramine. In the forced swimming test, beta-amyrin palmitate, like mianserin and imipramine, reduced the duration of immobility of mice significantly in a dose-dependent manner (5, 10 and 20 mg kg-1). beta-Amyrin palmitate (5, 10 and 20 mg kg-1) or mianserin (5, 10 and 20 mg kg-1) elicited a dose-related reduction in locomotor activity of mice and antagonized locomotor stimulation induced by methamphetamine. In contrast, imipramine (5, 10 and 20 mg kg-1) increased locomotor activity and potentiated methamphetamine-induced hyperactivity. beta-Amyrin palmitate showed no effect on reserpine-induced hypothermia, whilst mianserin (10 mg kg-1) and imipramine (10 and 20 mg kg-1) antagonized the reserpine-induced effect. Unlike imipramine, beta-amyrin palmitate and mianserin did not affect haloperidol-induced catalepsy, tetrabenazine-induced ptosis and apomorphine-induced stereotypy. beta-Amyrin palmitate and imipramine had no effects on the head-twitch response induced by 5-hydroxytryptophan, whereas mianserin (5, 10 and 20 mg kg-1) decreased it in a dose-dependent manner. A potentiating effect of beta-amyrin palmitate (5, 10 and 20 mg kg-1) on narcosis induced by sodium pentobarbitone was stronger than that of imipramine (10, 20 and 40 mg kg-1) but weaker than that of mianserin (2.5, 5 and 10 mg kg-1). These results suggest that beta-amyrin palmitate has similar properties in some respects to mianserin and might possess a sedative action.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Function of the ste signal transduction pathway for mating pheromones sustains MAT alpha 1 transcription in Saccharomyces cerevisiae.

Sterile mutants of Saccharomyces cerevisiae were isolated from alpha * cells having the a/alpha aar1-6 genotype (exhibiting alpha mating ability and weak a mating ability as a result of a defect in a1-alpha 2 repression). Among these sterile mutants, we found two ste5 mutants together with putative ste7, ste11, and ste12 mutants of the signal transduction pathway of mating pheromones. The amino acid sequence of the Ste5p protein predicted from the nucleotide sequence of a cloned STE5 DNA has a domain rich in acidic amino acids close to its C terminus, a cysteine-rich sequence, resembling part of a zinc finger structure, in its N-terminal half, and a possible target site of cyclic AMP-dependent protein kinase at its C terminus. Northern (RNA) blot analysis revealed that STE5 transcription is under a1-alpha 2-Aar1p repression. The MAT alpha 1 cistron has a single copy of the pheromone response element in its 5' upstream region, and its basal level of transcription was reduced in these ste mutant cells. However, expression of the MAT alpha 1 cistron was not enhanced appreciably by pheromone signals. One of the ste5 mutant alleles conferred a sterile phenotype to a/alpha aar1-6 cells but a mating ability to MATa cells.

Adaptor Proteins, Signal Transducing↗
PubMed1993

MKK1 and MKK2, which encode Saccharomyces cerevisiae mitogen-activated protein kinase-kinase homologs, function in the pathway mediated by protein kinase C.

The PKC1 gene of Saccharomyces cerevisiae encodes a homolog of mammalian protein kinase C that is required for normal growth and division of yeast cells. We report here the isolation of the yeast MKK1 and MKK2 (for mitogen-activated protein [MAP] kinase-kinase) genes which, when overexpressed, suppress the cell lysis defect of a temperature-sensitive pkc1 mutant. The MKK genes encode protein kinases most similar to the STE7 product of S. cerevisiae, the byr1 product of Schizosaccharomyces pombe, and vertebrate MAP kinase-kinases. Deletion of either MKK gene alone did not cause any apparent phenotypic defects, but deletion of both MKK1 and MKK2 resulted in a temperature-sensitive cell lysis defect that was suppressed by osmotic stabilizers. This phenotypic defect is similar to that associated with deletion of the BCK1 gene, which is thought to function in the pathway mediated by PCK1. The BCK1 gene also encodes a predicted protein kinase. Overexpression of MKK1 suppressed the growth defect caused by deletion of BCK1, whereas an activated allele of BCK1 (BCK1-20) did not suppress the defect of the mkk1 mkk2 double disruption. Furthermore, overexpression of MPK1, which encodes a protein kinase closely related to vertebrate MAP kinases, suppressed the defect of the mkk1 mkk2 double mutant. These results suggest that MKK1 and MKK2 function in a signal transduction pathway involving the protein kinases encoded by PKC1, BCK1, and MPK1. Genetic epistasis experiments indicated that the site of action for MKK1 and MKK2 is between BCK1 and MPK1.

Amino Acid Sequence↗
PubMed1993

[Blalock-Taussig shunts in infants less than 6 months of age with special reference to the long-term administration of prostaglandin E1].

Classical Blalock-Taussig (B-T) shunt operation was performed in 14 neonates (group N) and 22 infants (group P). A mean age of group N patients was thirteen days and that of group P patients was two months. Preoperatively prostaglandin E1 (PGE1) was administered in all patients and was continued for a mean of 7 days (range 2 hours to 21 days) in group N, and a mean of 78 days (range 42 to 158 days) in group P. Body weight (4359 +/- 339 g), size of subclavian artery (3.7 +/- 0.5 mm in diameter) and size of pulmonary artery (6.4 +/- 1.2 mm in diameter) at operation of group P patients were larger than those (3212 +/- 490 g, 3.4 +/- 0.4 mm, 5.1 +/- 1.3 mm) of group N. But there were no differences in operation time (165 +/- 22 minutes in group N vs 174 +/- 25 minutes in group P) and clamp time of pulmonary artery (31 +/- 10 minutes in group N vs 30 +/- 5 minutes in group P) between 2 groups. There was no operative death in both groups. There were one late death in group N and three late death in group P. Five patients in group N and nine patients in group P required additional B-T shunt at the mean follow up interval of two years.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1993

[Early and long-term results of sternocostal elevation combined with bridge external traction for funnel chest in children].

The purpose of the present study is to evaluate the effects of addition of a bridge external traction to our conventional sternocostal elevation technique in the surgical management of funnel chest in children. During the period from 1970 to 1979, a total of 29 children with funnel chest were treated surgically using sternocostal elevation technique (Group I). Operative technique consisted of total subperichondral resection of deformed costal cartilages (usually 3rd to 8th, bilaterally), transection of deformed portion of the sternum in 2-3 points and fixation of the sternum in elevated position using 2 Kirschner wires, and shortening resuturing of the opened perichondrium. Since 1980, an addition of the bridge external traction to our conventional sternocostal elevation technique was applied for about 10 days after operation in 82 consecutive children (Group II). The vertebral index (B/A = sagittal diameter of vertebral body/minimum sternovertebral distance), D/C ratio (maximum sagittal depth of depression of sternum/distance from anterior surface of the vertebral body to the sternum at Louis's angle) and E/C ratio (E = minimal sagittal distance from anterior surface of the vertebral body to the sternum) were measured in all cases and compared before and after operation and also between the two Groups. Preoperatively, there was no significant difference in all 3 indices between the two Groups. Postoperative B/A, D/C and E/C ratio in Group I were 0.28 +/- 0.06, 0.14 +/- 0.19, 1.09 +/- 0.32 (mean +/- SD), respectively. There were a significant drop in D/C ratio and a significant elevation in E/C ratio after operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Functional analysis of Box II mutations in yeast site-specific recombinases Flp and R. Significance of amino acid conservation within the Int family and the yeast sub-family.

The site-specific recombinases Flp and R from Saccharomyces cerevisiae and Zygosaccharomyces rouxii, respectively, are related proteins that share approximately 30% amino acid matches. They exhibit a common reaction mechanism that appears to be conserved within the larger Integrase family of site-specific recombinases. Two regions of the proteins, designated as Box I and Box II, harbor, in addition to amino acid conservation, a significantly high degree of nucleotide sequence homology within their coding segments. Box II also contains two amino acids, a histidine and an arginine, that are invariant throughout the Int family. We have performed functional analysis of Flp and R variants carrying point mutations within the Box II segment. Several positions within Box II can tolerate substitutions with no effect, or only modest effects on recombination. Alterations of the Int family residues, His305 and Arg308, in the R protein lead to the arrest of recombination at the strand cleavage or the strand exchange step. This is very similar to previously observed "step-arrest" phenotypes in Flp variants altered at these positions and has strong implications for the catalytic mechanism of recombination. Flp and R variants at His305 and His309 can be complemented in half-site strand transfer by a corresponding Tyr343 to phenylalanine variant. In contrast to Arg308 Flp variants, which are efficiently complemented in half-site strand transfer by Flp(Y343F), no strong complementation has been observed between Arg308 variants of R and R (Y343F).

DNA Mutational Analysis↗
PubMed1992

Automatic elimination of unnecessary bacterial sequences from yeast vectors.

Most vectors for Saccharomyces cerevisiae are shuttle vectors which can be both propagated and selected in Escherichia coli. The DNA segments, however, which are required for propagation in E. coli are unnecessary and moreover toxic in S. cerevisiae. To delete these harmful DNA fragments from the vector after it is introduced into S. cerevisiae cells, we propose a specific gene conversion mechanism of a yeast plasmid, pSR1. Plasmid pSR1 has a pair of inverted repeats (IRs) that divides the plasmid molecule into two unique regions. Intramolecular recombination frequently occurs at a pair of specific recombination sites in IRs catalyzed by recombinase R, encoded by a pSR1 plasmid gene. This R-mediated recombination is often accompanied by gene conversion in IRs. Thus, a 2.1-kb pBR322 sequence for the E. coli host ligated into one of the IRs of a composite plasmid was automatically and effectively eliminated when the plasmid was introduced into S. cerevisiae cells.

DNA, Bacterial↗
PubMed1992

Half-site recombinations mediated by yeast site-specific recombinases Flp and R.

The Flp recombinase of Saccharomyces cerevisae and the related R recombinase of Zygosaccharomyces rouxii can efficiently catalyze strand cleavage and strand exchange reactions in half recombination sites. A half-site consists of one recombinase binding element, a recombinase cleavage site on one strand and a 5' spacer hydroxyl group on the other that can initiate the strand exchange reaction. We have studied the various types of strand exchanges that half-sites can participate in. Reaction between a left half-site and a right half-site generates a full recombination site. Strand transfer between two left half-sites or between two right half-sites produces pseudo-full-sites. Strand transfer within a half-site results in a stem-loop or hairpin product. The half-site strand transfer reaction is fairly indifferent to the spacer sequence of the substrate per se and is less sensitive to variations in spacer lengths than a full-site recombination reaction. The optimal spacer length of eight to ten nucleotides observed for the Flp half-site reaction likely permits the most productive catalytic interactions between two Flp monomers bound to each of two partner half-sites. When reacted with a full-site, the half-site can give rise to a normal or reverse recombinant, corresponding to homologous or non-homologous alignments of the spacer sequences during substrate synapsis. The contrary recombination (resulting from non-homologous spacer alignment), whose level is low relative to normal recombination, is partly suppressed when the half-site spacer ends in a 5'-phosphate rather than a 5'-hydroxyl group. Thus, the early steps of recombination, namely synapsis and initial stand transfer, are not dependent on complete spacer homology between the two recombining substrates. The selection of properly aligned substrate partners must occur at the homology dependent branch migration step. In reactions containing a mixture of Flp and R half-sites, Flp and R catalyze strand transfer, almost exclusively, within or between their respective cognate substrates. However, under conditions where self-crosses are inhibited, strand exchange between a Flp half-site and an R half-site appears to be stimulated by a combination of R and Flp.

Base Sequence↗
PubMed1992

Site-specific recombinase, R, encoded by yeast plasmid pSR1.

The R gene product (R protein) of Zygosaccharomyces rouxii plasmid pSR1 catalyzes site-specific recombination within a 58 base-pair (bp) sequence present in the 959 bp inverted repeats of this plasmid. The R protein was produced in Escherichia coli and partially purified. The partially purified protein catalyzed site-specific recombination in vitro without the supply of an energy source. Recombination resulted in intramolecular inversion or deletion, depending on whether the orientations of the two recombination sites on the substrate plasmid were the same or opposite. Presumably, R protein is the only protein required for the recombination reaction. A circular DNA molecule appears to be a better substrate than a linear molecule in R-mediated in vitro intramolecular recombination. The R protein binds to a set of six 12 bp elements within the inverted repeats of pSR1. Two of these 12 bp elements are arranged in an inverted configuration with a 7 bp spacer in the 58 bp sequence. The R protein mediates strand cleavage in vitro at the junction between the 12 bp elements and the 7 bp spacer. The cleavage sites on the top and bottom strands are staggered and flanked by polypurine tracts that form part of the 12 bp elements.

Base Sequence↗
PubMed1992

The CDC26 gene of Saccharomyces cerevisiae is required for cell growth only at high temperature.

We have cloned and sequenced the wild-type CDC26 gene and a mutant allele, cdc26-1, of Saccharomyces cerevisiae. Nucleotide sequence analysis revealed that the gene we cloned was the same as SCD26, a dosage-dependent suppressor of cdc26. However, the cloned gene is in fact the CDC26 gene, because a nucleotide substitution in cdc26-1 was found to be a nonsense mutation in this sequence. Disruption of this gene conferred thermosensitive cell growth and the disrupted cdc26 gene could not complement the cdc26-1 mutant allele. Thus, the CDC26 gene is required for cell growth only at high temperature.

Amino Acid Sequence↗
PubMed1992

A case of congenital leukemia with monosomy 7.

A case of congenital leukemia with monosomy 7 is reported. Immunological study of the blast cells using monoclonal antibodies was suggestive of both myelomegakaryocytic and T-lymphoblastic leukemia. Chromosomal analysis of the bone marrow cells showed monosomy 7. Chemotherapy was initiated with a combination of adriamycin, cytosine arabinoside, 6-mercaptopurine, and prednisolone. The patient obtained complete remission, which has been maintained for 4 years and 1 month. He receives no chemotherapy now. Our case shows that monosomy 7 in congenital leukemia is rare, but the presence of monosomy 7 in congenital leukemia does not necessarily indicate a poor prognosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Systemic atrioventricular valve replacement in an infant with corrected transposition of the great arteries.

A 3-month-old infant with corrected transposition of the great arteries and severe systemic atrioventricular valve regurgitation due to "Ebstein-like anomaly" is reported. Through a right thoracotomy and longitudinal left atrial incision, a 19-mm St. Jude Medical valve was implanted into the annulus without removing the native valve. He is doing well 7 months after operation.

Ebstein Anomaly↗
PubMed1992

Toxin composition of resting cysts of Alexandrium tamarense (Dinophyceae).

Paralytic shellfish toxin composition in the resting cysts of the dinoflagellate Alexandrium tamarense was investigated by means of high performance liquid chromatography. A comparison was made between cysts collected from ship ballast tank sediments, natural population of motile vegetative cells collected from the area where ballast water was taken, as well as cultured vegetative cells established from the cysts and the natural plankton bloom. Total toxin concentration of the cysts (595 fmole/cell) was six-fold higher than that of the natural population of vegetative cells. They contained the same ten toxic components but in different relative abundances. The higher proportion of 11-alpha-hydroxysulfate epimers in the cysts suggests that the biosynthesis of toxins is halted at an early stage in cyst formation.

Animals↗
PubMed1992

Putative GTP-binding protein, Gtr1, associated with the function of the Pho84 inorganic phosphate transporter in Saccharomyces cerevisiae.

We have found an open reading frame which is 1.1 kb upstream of PHO84 (which encodes a Pi transporter) and is transcribed from the opposite strand. In Saccharomyces cerevisiae, this gene is distal to the TUB3 locus on the left arm of chromosome XIII and is named GTR1. GTR1 encodes a protein consisting of 310 amino acid residues containing, in its N-terminal region, the characteristic tripartite consensus elements for binding GTP conserved in GTP-binding proteins, except for histidine in place of a widely conserved aspargine residue in element III. Disruption of the GTR1 gene resulted in slow growth at 30 degrees C and no growth at 15 degrees C; other phenotypes resembled those of pho84 mutants and included constitutive synthesis of repressible acid phosphatase, reduced Pi transport activity, and resistance to arsenate. The latter phenotypes were shown to be due to a defect in Pi uptake, and the Gtr1 protein was found to be functionally associated with the Pho84 Pi transporter. Recombination between chromosome V (at the URA3 locus) and chromosome XIII (in the GTR1-PHO84-TUB3 region) by using a plasmid-encoded site-specific recombination system indicated that the order of these genes was telomere-TUB3-PHO84-GTR1-CENXIII.

Acid Phosphatase↗