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H Sassa

Publications and source records attributed to H Sassa.

At least 19 recordsLinked to original sources
PubMed2001

OsPAA2, a distinct alpha 1 subunit gene for the 20S proteasome in rice (Oryza sativa L.).

The 20S proteasome is the proteolytic complex that is involved in removing abnormal proteins and other diverse biological functions. The 20S proteasome is constituted of 28 subunits arranged in four rings of seven subunits, and exists as a hollow cylinder. The two outer rings and the two inner rings are composed of seven different alpha and beta type subunits, respectively, giving an alpha 7 beta 7 beta 7 alpha 7 structure. We previously reported the primary structures of the 14 proteasomal subunit subfamilies in rice (Oryza sativa), representing the first set for all the subfamilies from monocot. In this study, a distinct cDNA sequence encoding the alpha1 subunit, OsPAA2, was identified. The amino acid sequence similarity between the two rice alpha1 subunits was as low as 59.6%, contrasting with those between paralogs of Arabidopsis proteasome subunit genes. The expression pattern of the OsPAA2 gene was different from that of another alpha1 gene, OsPAA1. These data suggest that OsPAA2 might play a distinct role from that of OsPAA1 in the 20S proteasome complex.

Amino Acid Sequence↗
PubMed2001

Characterization of the S-locus region of almond (Prunus dulcis): analysis of a somaclonal mutant and a cosmid contig for an S haplotype.

Almond has a self-incompatibility system that is controlled by an S locus consisting of the S-RNase gene and an unidentified "pollen S gene." An almond cultivar "Jeffries," a somaclonal mutant of "Nonpareil" (S(c)S(d)), has a dysfunctional S(c) haplotype both in pistil and pollen. Immunoblot and genomic Southern blot analyses detected no S(c) haplotype-specific signal in Jeffries. Southern blot showed that Jeffries has an extra copy of the S(d) haplotype. These results indicate that at least two mutations had occurred to generate Jeffries: (1) deletion of the S(c) haplotype and (2) duplication of the S(d) haplotype. To analyze the extent of the deletion in Jeffries and gain insight into the physical limit of the S locus region, approximately 200 kbp of a cosmid contig for the S(c) haplotype was constructed. Genomic Southern blot analyses showed that the deletion in Jeffries extends beyond the region covered by the contig. Most cosmid end probes, except those near the S(c)-RNase gene, cross-hybridized with DNA fragments from different S haplotypes. This suggests that regions away from the S(c)-RNase gene can recombine between different S haplotypes, implying that the cosmid contig extends to the borders of the S locus.

Base Sequence↗
PubMed2001

Pharmacological properties of fidarestat, a potent aldose reductase inhibitor, clarified by using sorbitol in human and rat erythrocytes.

We examined the effect of fidarestat on the increase in sorbitol content in erythrocytes from healthy volunteers in vitro. Fidarestat inhibited the increase with an IC50 value of 18 nmol/l. A subsequent experiment showed that fidarestat had a similar inhibitory effect on the increase in sorbitol content in erythrocytes from diabetic patients. On the other hand, epalrestat, the only aldose reductase inhibitor used clinically, inhibited increase in sorbitol content at a concentration over 500-fold higher than fidarestat. Although the IC50 value of fidarestat was not affected by fasting plasma glucose, HbA1C, age, aldose reductase content or gender, there was a significant positive relationship between the IC50 value of epalrestat and fasting plasma glucose. In addition, in fidarestat (0.25-2 mg/kg)-treated diabetic rats, the inhibitory rate for erythrocyte sorbitol accumulation was well correlated with that for nerve sorbitol accumulation, which indicates that erythrocyte sorbitol is available for assessing the state of sorbitol pathway flux in target tissue after fidarestat administration. These results suggest that fidarestat potently inhibits the increase in sorbitol pathway flux in diabetic patients independent of various factors and that erythrocyte sorbitol is useful for its estimation.

Age Factors↗
PubMed2000

Primary structural features of the 20S proteasome subunits of rice (Oryza sativa).

The 20S proteasome is the proteolytic complex that is involved in removing abnormal proteins, and it also has other diverse biological functions. Its structure comprises 28 subunits arranged in four rings of seven subunits, and exists as a hollow cylinder. The two outer rings and two inner rings form an alpha7beta7beta7alpha7 structure, and each subunit, alpha and beta, exists as seven different types, thus giving 14 kinds of subunits. In this study, we report the primary structures of the 14 proteasomal subunit subfamilies in rice (Oryza sativa), representing the first set for all of the subunits from monocots. Amino acid sequence homology within the rice family (alpha-type: 28.9-42.1%; beta-type: 17.2-31. 9%) were lower than those between rice subunits and corresponding orthologs from Arabidopsis and yeast (alpha-type: 49.2-94.5%; beta-type: 34.8-87.7%). Structural features observed in eukaryotic proteasome subunits, i.e., alpha- or beta-type signature at the N-termini, Thr active sites in beta1, beta2 and beta5 subunits, and nuclear localization signal-like sequences in some alpha-type subunits, were shown to be conserved in rice.

Amino Acid Sequence↗
PubMed2000

N(alpha)-acetylation and proteolytic activity of the yeast 20 S proteasome.

N(alpha)-acetylation, catalyzed co-translationally with N(alpha)-acetyltransferase (NAT), is the most common modifications of eukaryotic proteins. In yeast, there are at least three NATs: NAT1, MAK3, and NAT3. The 20 S proteasome subunits were purified from the normal strain and each of the deletion mutants, nat1, mak3, and nat3. The electrophoretic mobility of these subunits was compared by two-dimensional gel electrophoresis. Shifts toward the alkaline side of the gel and unblocking of the N terminus of certain of the subunits in one or another of the mutants indicated that the alpha1, alpha2, alpha3, alpha4, alpha7, and beta3 subunits were acetylated with NAT1, the alpha5 and alpha6 subunits were acetylated with MAK3, and the beta4 subunit was acetylated with NAT3. Furthermore, the Ac-Met-Phe-Leu and Ac-Met-Phe-Arg termini of the alpha5 and alpha6 subunits, respectively, extended the known types of MAK3 substrates. Thus, nine subunits were N (alpha)-acetylated, whereas the remaining five were processed, resulting in the loss of the N-terminal region. The 20 S proteasomes derived from either the nat1 mutant or the normal strain were similar in respect to chymotrypsin-like, trypsin-like, and peptidylglutamyl peptide hydrolyzing activities in vitro, suggesting that N(alpha)-acetylation does not play a major functional role in these activities. However, the chymotrypsin-like activity in the absence of sodium dodecyl sulfate was slightly higher in the nat1 mutant than in the normal strain.

Acetylation↗
PubMed2000

Two-dimensional gel electrophoresis using immobilized pH gradient tube gels.

An apparatus for the preparation of gels for immobilized pH gradient isoelectric focusing (IPG) in glass tubes was developed. Using this apparatus, the highly reproducible immobilized pH gradient can be formed with Immobilines in polyacrylamide gels, and IPG gels at all possible pH ranges can be easily prepared at low cost. The IPG tube gels in the first dimension in two-dimensional gel electrophoresis was used to separate and identify a number of rice embryo proteins in the proteome analysis. There was no difference in resolution of proteins between the tube gels and the commercially available slab gels; after electrophoresis, however, we could efficiently obtain a larger amount of the purified proteins from the tube gels than from the slab gels.

Animals↗
PubMed1999

Prediction of cerebral infarct sizes by cerebral blood flow SPECT performed in the early acute stage.

Cerebral infarct due to embolic stroke without recanalization was examined by cerebral blood flow (CBF) SPECT in the early acute stage, and the possibility of predicting the size it will reach in the later stages was evaluated. Twenty patients (67 +/- 13 years) were examined by CBF SPECT with 99mTc-ECD 4.5 +/- 3.1 hours after the onset of cardiogenic cerebral embolism. The ratio of the anteroposterior length of the cerebral hemisphere to that of the severe ischemic region, which was defined as an area of clear-cut severe reduction in CBF as observed by SPECT, was calculated. One week after the onset, the cerebral infarct was measured in the same manner by CT, and the relationship between the two measurements was evaluated. The CBF in the region of severe ischemia and the surrounding region was determined by the Patlak plot method, and the affected/non-affected (A/NA) ratio was calculated. In severe ischemic regions the CBF ranged from 1.7 ml/100 g/min to 20 ml/100 g/min (mean, 11 +/- 5 ml/100 g/min), whereas the A/NA ratio ranged from 4% to 45% (mean, 26 +/- 11%). On the other hand, the CBF in the surrounding regions ranged from 20 ml/100 g/min to 52 ml/100 g/min (mean, 34 +/- 8 ml/100 g/min) whereas the A/NA ratio ranged from 52% to 104% (mean, 77 +/- 11%). The coefficient of correlation between the infarct size predicted by SPECT and that measured by CT was r = 0.986, and the correlation equation was Y = 1.047X - 2.969. CBF SPECT performed in the early acute stage can be used to predict the size of cerebral infarct.

Aged↗
PubMed1998

Characterization of the flanking regions of the S-RNase genes of Japanese pear (Pyrus serotina) and apple (Malus x domestica).

Genomic sequences of the self-incompatibility genes, the S-RNase genes, from two rosaceous species, Japanese pear and apple, were characterized. Genomic Southern blot and sequencing of a 4.5-kb genomic clone showed that the S4-RNase gene of Japanese pear is surrounded by repetitive sequences as in the case of the S-RNase genes of solanaceous species. The flanking regions of the S2- and Sf-RNase genes of apple were also cloned and sequenced. The 5' flanking regions of the three alleles bore no similarity with those of the solanaceous S-RNase genes, although the position and sequence of the putative TATA box were conserved. The putative promoter regions of the Japanese pear S4- and apple Sf-RNase genes shared a stretch of about 200bp with 80% sequence identity. However, this sequence was not present in the S2-RNase gene of apple, and thus it may reflect a close relationship between the S4- and Sf-RNase genes rather than a cis-element important in regulating gene expression. Despite the uniform pattern of expression of the rosaceous S-RNase genes, sequence motifs conserved in the 5' flanking regions of the three alleles were not found, implying that the cis-element controlling pistil specific gene expression also locates at the intragenic region or upstream of the analyzed promoter region.

Amino Acid Sequence↗
PubMed1998

Style-specific and developmentally regulated accumulation of a glycosylated thaumatin/PR5-like protein in Japanese pear (Pyrus serotina Rehd.).

The stylar proteins of Japanese pear (Pyrus serotina Rehd.) were analyzed by two-dimensional gel electrophoresis, and a 32-kDa protein with an isoelectric point of 4.8 was found to be a major component in the style. The 32-kDa protein was a soluble glycoprotein which reacted with concanavalin A. The 32-kDa protein specifically accumulated in the style in a developmentally regulated manner, but was not detected in the other floral organs and leaves. An oligonucleotide representing the N-terminal amino acid sequence of the 32-kDa protein was used to amplify a cDNA fragment by polymerase chain reaction (PCR). The generated PCR product was used to screen a style cDNA library. The selected cDNA clone encoded 244 amino acid residues containing the N-terminal sequence of the 32-kDa protein. The N-terminus of the protein was preceded by putative signal peptide of 22 amino acid residues. The 32-kDa protein showed significant homology with the thaumatin/PR5-like proteins, and was named PsTL1 (Pyrus serotina thaumatin-like protein 1). The possible biological role of PsTL1 in the styles is discussed.

Amino Acid Sequence↗
PubMed1998

Cloning and characterization of cDNAs encoding S-RNases from almond (Prunus dulcis): primary structural features and sequence diversity of the S-RNases in Rosaceae.

cDNAs encoding three S-RNases of almond (Prunus dulcis), which belongs to the family Rosaceae, were cloned and sequenced. The comparison of amino acid sequences between the S-RNases of almond and those of other rosaceous species showed that the amino acid sequences of the rosaceous S-RNases are highly divergent, and intra-subfamilial similarities are higher than inter-subfamilial similarities. Twelve amino acid sequences of the rosaceous S-RNases were aligned to characterize their primary structural features. In spite of their high level of diversification, the rosaceous S-RNases were found to have five conserved regions, C1, C2, C3, C5, and RC4 which is Rosaceae-specific conserved region. Many variable sites fall into one region, named RHV. RHV is located at a similar position to that of the hypervariable region a (HVa) of the solanaceous S-RNases, and is assumed to be involved in recognizing S-specificity of pollen. On the other hand, the region corresponding to another solanaceous hypervariable region (HVb) was not variable in the rosaceous S-RNases. In the phylogenetic tree of the T2/S type RNase, the rosaceous S-RNase fall into two subfamily-specific groups (Amygdaloideae and Maloideae). The results of sequence comparisons and phylogenetic analysis imply that the present S-RNases of Rosaceae have diverged again relatively recently, after the divergence of subfamilies.

Amino Acid Sequence↗
PubMed1998

Characteristics of prehospital cardiac arrest patients in Japan and determinant factors for survival.

Two hundred forty-seven consecutive patients who had prehospital cardiac arrest and were transferred to a municipal hospital were studied to elucidate the characteristics of these patients and to investigate factors for improving the survival rate among prehospital cardiac arrest patients. Detailed information on 130 patients with cardiac etiology was analyzed: 110 were confirmed dead in the emergency department (group A); 14 survived less than 1 week (group B); 6 survived longer than 1 week (group C). Only one patient received cardiopulmonary resuscitation (CPR) from a bystander, and none received electrical defibrillation before arriving at hospital because, at the time, emergency personnel were not allowed to perform advanced life support (ALS) in Japan. The three characteristics for better prognosis after prehospital cardiac arrest were found to be as follows: being witnessed on collapse, receiving prompt ALS, and ventricular fibrillation on arrival at hospital. The survival rate would have been higher if more lay people could have performed CPR and if emergency unit personnel had been allowed to perform ALS.

Aged↗
PubMed1998

Inhibitory effects of pentamethine trinuclear cyanine dyes on ADP/Fe2+-induced lipid peroxidation in rat liver mitochondria: changes in the mode of action with the hydrophobic nature of the dyes.

The effects of various pentamethine trinuclear cyanine dyes, each of which has three alkyl chains, on ADP/Fe2+-induced lipid peroxidation in rat liver mitochondria were examined. Although the dye having the shortest -C2H5 chains (tri-S-C2(5)) did not show any appreciable effect, the dyes having -C4H9 (tri-S-C4(5)), -C7H15 (tri-S-C7(5)), and -C12H25 (tri-S-C12(5)) chains significantly inhibited lipid peroxidation, the most potent inhibitory effect being observed with tri-S-C7(5). The mode of antiperoxidation effect of the dyes was dependent on the length of the alkyl chains. The relatively hydrophilic dye tri-S-C4(5) was suggested to scavenge radicals more efficiently at or near the membrane surface rather than in the interior of the lipid membrane, whereas the more hydrophobic dye tri-S-C7(5) was suggested to scavenge radicals efficiently in the membrane rather than at or near the membrane surface. The hydrophilic/hydrophobic balance of the dye was found to regulate the site of action of the dyes.

Adenosine Diphosphate↗
PubMed1997

Identification of stylar RNases associated with gametophytic self-incompatibility in almond (Prunus dulcis).

Stylar proteins of 13 almond (Prunus dulcis) cultivars with known S-genotypes were surveyed by IEF and 2D-PAGE combined with immunoblot and N-terminal amino acid sequence analyses to identify S-RNases associated with gametophytic self-incompatibility (SI) in this plant species. RNase activities corresponding to Sa and Sb, two of the four S-alleles tested, were identified by IEF and RNase activity staining. The Sa-RNase band reacted with the anti-S4-serum prepared from Japanese pear (Pyrus serotina); no reaction with the antiserum was observed with the Sb-RNase band. When the Sa-RNase band was excised from an IEF gel stained for RNase activity, subjected to SDS-PAGE, and detected by immunoblotting, it appeared that this band consisted of a single protein that reacted with the anti-S4-serum with M(r) of about 28 kDa. With 2D-PAGE and silver staining of the stylar extracts, all four S-proteins could be successfully distinguished from each other in the highly basic zone of the gel. Although Sb-, Sc-, and Sd-proteins had roughly the same M(r) of about 30 kDa, the Sc-protein seemed to be slightly smaller than the Sb-protein and slightly larger than the Sd-protein. In 2D-PAGE profiles as well, the Sa-protein had M(r) of about 28 kDa, apparently smaller than the other three proteins. A bud sport, in which one of the two S-alleles of the original cultivar is impaired, was visualized as a loss of Sc-protein, which is consistent with the previous pollination study. All four S-proteins reacted with the anti-S4-serum, probably because of the differing conformations of these S-proteins in the IEF and 2D-PAGE gels. The Sa-protein in 2D-PAGE appeared to be identical to Sa-RNase in IEF; both had the same M(r) and were reactive with the anti-S4-serum. N-terminal amino acid sequence analysis of the four S-proteins revealed that they were highly homologous to each other and similar to the S-RNases of Malus, Pyrus, Scrophulariaceae, and Solanaceae. Taken together, RNases in the style are strongly suggested to be associated with the gametophytic SI of almond. This is the first report identifying and characterizing S-RNase in almond.

Amino Acid Sequence↗
PubMed1997

A case of amiodarone-induced thyrotoxicosis successfully treated with prednisolone.

We describe a patient who was treated with amiodarone for ventricular arrhythmia based on arrhythmogenic right ventricular dysplasia and who subsequently developed severe amiodarone-induced thyrotoxicosis. Discontinuation of amiodarone resulted in sustained ventricular tachycardia, which was successfully treated with a DC electrical shock, and subsequently atrial fibrillation, leading to brain embolism due to occlusion of the left middle cerebral artery. Combination treatment with amiodarone and prednisolone was effective both in reducing the serum concentration of thyroid hormones and in improving the patient's general condition. As the use of amiodarone becomes more widespread, treatment with prednisolone for this kind of thyrotoxicosis, which is resistant to conventional treatment, will be required increasingly frequently because iodine overload of the thyroid gland persists for some time after discontinuation of amiodarone treatment.

Adult↗
PubMed1997

Prevalence of activated protein C resistance in acute myocardial infarction in Japan.

To investigate the possibility that activated protein C (APC) resistance due to the factor V could be an important predisposing factor in acute myocardial infarction (AMI), we have retrospectively examined the prevalence of APC resistance with protein C, protein S and antithrombin III deficiency and antiphospholipid antibody syndrome in AMI patients (< or = 50 years) admitted to our hospital over the past 7 years. Forty-seven patients were enrolled in the study. We divided the patients into two groups, warfarin group (group A) and a non-warfarin group (group B). APC resistance is defined as when the APC ratio is below or equal to the cut-off value 2. APC resistance was not detected in either group. The prevalence of an APC ratio below or equal to 2.5 was 16.7% (1 case) in group A and 24.4% (10 cases) in group B. The prevalence of protein C deficiency was 5.0% (2 cases) in group B. Two cases (5.0%) in group B had protein S deficiency. Antithrombin III deficiency was not detected in either group. The prevalence of antiphospholipid antibody syndrome measured by APTT was 40.4% (19 cases). We compared the AMI patients with 97 healthy volunteers (< or = 50 years old) without any thromboembolic events or bleeding tendency in their past history. No significant difference were found between these groups and the volunteers. APC resistance is a major cause of venous thromboembolism in Europe and the United States, while in Japan it is believed to be a minor cause of arterial thromboembolism.

Adult↗
PubMed1996

Self-incompatibility (S) alleles of the Rosaceae encode members of a distinct class of the T2/S ribonuclease superfamily.

Stylar ribonucleases (RNases) are associated with gametophytic self-incompatibility in two plant families, the Solanaceae and the Rosaceae. The self-incompatibility-associated RNases (S-RNases) of both the Solanaceae and the Rosaceae were recently reported to belong to the T2 RNase gene family, based on the presence of two well-conserved sequence motifs. Here, the cloning and characterization of S-RNase genes from two species of Rosaceae, apple (Malus x domestica) and Japanese pear (Pyrus serotina) is described and these sequences are compared with those of other T2-type RNases. The S-RNases of apple specifically accumulated in styles following maturation of the flower bud. Two cDNA clones for S-RNases from apple, and PCR clones encoding a further two apple S-RNases as well as two Japanese pear S-RNases were isolated and sequenced. The deduced amino acid sequences of the rosaceous S-RNases contained two conserved regions characteristic of the T2/S-type RNases. The sequences showed a high degree of diversity, with similarities ranging from 60.4% to 69.2%. Interestingly, some interspecific sequence similarities were higher than those within a species, possibly indicating that diversification of S-RNase alleles predated speciation in the Rosaceae. A phylogenetic tree of members of the T2/S-RNase superfamily in plants was obtained. The rosaceous S-RNases formed a new lineage in the tree that was distinct from those of the solanaceous S-RNases and the S-like RNases. The findings suggested that self-incompatibility mechanisms in Rosaceae and Solanaceae are similar but arose independently in the course of evolution.

Alleles↗
PubMed1996

Diagnostic significance of thrombin-antithrombin III complex (TAT) and D-dimer in patients with deep venous thrombosis.

Thrombin-antithrombin III (TAT) and D-dimer were measured in 50 patients suspected of deep venous thrombosis (DVT) to assess the usefulness of these indicators in the diagnosis of DVT. DVT was diagnosed by ultrasonography (compression method and Doppler imaging). In patients who were negative for DVT (Group A), TAT was 3.8 +/- 2.36 micrograms/L (mean +/- SD) and D-dimer was 0.7 +/- 0.69 micrograms/ml, whereas in patients diagnosed with DVT (Group B), TAT was 20.4 +/- 19.10 micrograms/L (p < 0.001) and D-dimer was 9.0 +/- 9.21 micrograms/ml (p < 0.001). Thus, Group B had significantly higher levels of both markers. Moreover, 19 of the 23 cases in Group B had acute DVT, with symptoms appearing within 2 weeks of onset. When the cutoff for a positive diagnosis of DVT was set at TAT of 7.0 micrograms/L or more and D-dimer of 3.0 micrograms/ml or more, sensitivity was 84%, specificity was 96%, and accuracy was 90%. Based on these results, we concluded that TAT and D-dimer are extremely useful in screening for acute DVT.

Adult↗