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T Hiratsuka

Publications and source records attributed to T Hiratsuka.

At least 19 recordsLinked to original sources
PubMed1996

Immunohistochemical analysis of the endocrine cells in the pancreatic islets of cattle.

The distribution of endocrine cells and the areas of islets in the bovine pancreas were investigated by immunohistochemical methods. The islets in the A-region, which consisted of the left lobe, the ventral portion of the body, and the ventral and distal portions of the right lobe, contained a central core of insulin-containing (B-) cells surrounded by glucagon containing (A-) cells, a few somatostatin-containing (D-) cells and sporadic pancreatic polypeptide-containing (PP-) cells. The islets in the B-region, which consisted of the uncinate process, and the dorsal and proximal portions of the body and the right lobe, contained a central mass of B-cells, and peripheral cells which were predominantly PP-cells with a few D-cells but no A-cells. The areas of islets in the B-region were small as compared with those in the A-region. From these findings it is suggested that A- and PP-cells have a complementary relationship to one another. In view of this hypothesis, two types of islet, A-cell-rich and PP-cell-rich islets, were identified. The A-region contained A-cell-rich islets derived from the dorsal pancreatic primordium, while the B-region contained PP-cell-rich islets that originated from the ventral primordium. In the bovine pancreas, the areas containing PP-cell-rich islets are greater than those in previously examined species.

Animals↗
PubMed1995

Association of DQB1*0302 alloantigens in Japanese pediatric patients with steroid-sensitive nephrotic syndrome.

We identified human leukocyte alloantigens (HLA) class II alleles in 24 Japanese children with steroid-sensitive nephrotic syndrome (SSNS) by deoxyribonucleic acid (DNA) typing. The DQA1 and DQB1 alleles were identified using sequence-specific oligonucleotide probes for DQA and DQB. The frequency of DQB1*0302 was significantly higher in the patients than in the controls (54.0 vs. 16.0%, respectively; relative risk, RR = 6.2; pc < 0.00009. We also found that the frequency of DQA1*0103 in the patients was significantly lower than in the controls (RR = 0.194, pc < 0.04). Several studies have identified an association between certain HLA by serotyping. In the present study, we investigated the HLAs of Japanese patients with SSNS by DNA typing and observed a significant increase in the frequency of DQB1*0302 in patients with the disease. HLA-DQ3, which was proven to be associated with SSNS, consists of HLA DQ7, 8 and 9. DQB1*0302 is a component of HLA-DQ8. So we proposed the increase of DQ3 was due to an increase in DQ8.

Adolescent↗
PubMed1995

Fine structure of podocytes in the bovine renal corpuscle.

Thick primary processes issued from the hemispherical or plate-like cell bodies of podocytes in bovine renal corpuscles. These processes branched into secondary and tertiary ones, but no fine pedicels were observed on the outer surface of the podocytes by scanning electron microscopy, because each primary process closely interdigitated with those of adjacent cells. Many pedicels, however, were observed under the processes by using the freeze-fractograph and a transmission electron microscope.

Aging↗
PubMed1995

Microvascular changes in the bovine corpus luteum during pregnancy.

The microvasculature of bovine corpora lutea during pregnancy was studied by scanning electron microscopy using corrosion casts. Only one spiral arteriole branched directly from the ovarian artery entered the blood vascular bed of the pregnant corpora lutea. The bed consisted of numerous lobular sinusoidal capillary plexuses during pregnancy, and were characteristic to the microvasculature of a large corpus luteum. At the late stage of pregnancy, arteriovenous anastomoses were situated within the lobular sinusoidal capillary plexus composed of thin sinusoidal capillaries. These anastomoses may induce a decrease in blood flow to the lobular sinusoidal capillary plexus, suggesting that they may have an important role to induce the initial degeneration of the bovine pregnant corpora lutea.

Animals↗
PubMed1995

Traumatic occlusion of the anterior cerebral artery--case report.

A 71-year-old female presented with posttraumatic occlusion of the anterior cerebral artery (ACA) after a road accident in which she was hit in the mid-frontal region. Initial computed tomography (CT) demonstrated frontal skull fractures and pneumocephalus. High density areas were also identified in the right basal cisterns, suggesting traumatic subarachnoid hemorrhage. She was alert on admission, but with attendant shock due to crush wounds. Her condition rapidly deteriorated and an emergency amputation of her left leg was performed. After aggressive treatment with transfusion and infusion, her systolic pressure increased to 120 mmHg. Her consciousness remained disturbed. Serial CT disclosed hemorrhagic infarction in the entire medial side of the right frontal lobe. Magnetic resonance angiography demonstrated decreased flow voids in the bilateral A1 segments and right ACA, and a basilar artery aneurysm, which was unruptured clinically. Three weeks after the injury, she regained consciousness. Six months later, she had motor aphasia and left upper extremity weakness. The clinicopathological mechanism causing the traumatic occlusion of the ACA in the present case was probably dissecting aneurysm.

Adult↗
PubMed1994

Nucleotide-induced closure of the ATP-binding pocket in myosin subfragment-1.

The hydrophobic fluorescent dye 3-[4-(3-phenyl-2-pyrazolin-1-yl)benzene-1-sulfonylamido]phen ylboronic acid (PPBA) stoichiometrically binds to myosin subfragment-1 (S-1) with a dissociation constant (Kd) of 26 microns. Upon addition of nucleotides to the complex of S-1 with PPBA, the PPBA-binding site is converted to a more firm hydrophobic pocket accompanied by a large fluorescence change. For the complex formed with ATP, binding of the dye is competitive with respect to ATP with a Ki of 0.8 microns. This competition was confirmed by the result that the Kd value of S-1 with ATP was increased 3.3-fold by the addition of PPBA. The dye bound to S-1 senses ATP hydrolysis but has no effect on the binding of actin to S-1. Measurements of acrylamide fluorescence quenching of the complexes have revealed that the Stern-Volmer quenching constant of the dye is reduced by a factor of 2.7 during ATP hydrolysis. These results together with the fluorescent properties of the complexes suggest that the ATP-binding pocket of S-1 is closed and/or tightened during ATP hydrolysis.

Adenine Nucleotides↗
PubMed1993

Behavior of Cys-707 (SH1) in myosin associated with ATP hydrolysis revealed with a fluorescent probe linked directly to the sulfur atom.

4-Fluoro-7-sulfamoylbenzofurazan (ABDF) has a rather small fluorophore that is linked directly to the sulfur atom of thiols without a flexible alkyl chain (Imai, K., and Toyo'oka, T. (1987) Methods Enzymol. 143, 67-75). In the present study I examined the fluorescent and chemical properties of ABDF as an environmentally sensitive probe for Cys-707 (SH1) of myosin subfragment-1 (S-1) to monitor the behavior of SH1 associated with ATP hydrolysis. ABDF was very stable to long irradiation and nonfluorescent before attachment to thiols, permitting the continuous monitoring of the labeling reaction. The fluorophore was useful as an environmentally sensitive probe for thiol groups in proteins. SH1 of S-1 was specifically labeled with ABDF. When ATP, adenyl-5'-yl imidodiphosphate, and ADP were added to the labeled S-1 (ABD-S-1), the fluorescence intensity at 500 nm increased by 110, 66, and 53%, respectively. Binding of actin to ABD-S-1 resulted in a decrease in the fluorescence by 30%. The fluorophore attached to SH1 was found to be located in a more hydrophobic environment in the presence of ATP than in the absence of ligand. KI fluorescence quenching studies suggested that the binding of ATP causes a movement of SH1 toward a more hydrophobic protein interior, whereas it goes back to the opposite direction after ATP hydrolysis. Thus, ABDF is very useful as an environmentally sensitive fluorescent probe for SH1 that monitors ligand-induced changes in the behavior of the thiol.

Acrylamide↗
PubMed1993

Quality of life measurements using a linear analog scale for elderly patients with chronic lung disease.

We developed a linear analogue scale (QOL Scale) to measure the quality of life (QOL) in elderly patients with chronic lung disease. In this study, the validity of the QOL Scale was assessed and QOL Scale scores were compared with the results of other conventional questionnaires. A total of 76 subjects, aged 65 years or older, divided into three groups according to disease severity, were tested by the QOL Scale and two additional questionnaires. The QOL Scale had the advantages of comprehensibility, acceptability and reproducibility. QOL Scale scores differed among the groups, while the other questionnaires showed no significant differences according to disease severity. QOL Scale scores correlated with the tendency toward neurosis shown by another index. We conclude that the QOL Scale is a practical and useful indicator of QOL in elderly patients with chronic lung disease.

Aged↗
PubMed1992

Movement of Cys-697 in myosin ATPase associated with ATP hydrolysis.

To detect movement of Cys-697 (SH2) in myosin subfragment-1 (S-1) associated with ATP hydrolysis, SH2 was labeled with the environmentally sensitive fluorescent analog of maleimide, 2-(4'-maleimidylanilino)naphthalene-6-sulfonic acid (MIANS). Complex formation of S-1 labeled at Cys-697 with MIANS (MIANS-S-1) with adenyl-5'-yl imidodiphosphate and ADP resulted in a significant decrease in the fluorescence intensity of approximately 40 and 30%, respectively. When ATP was added to MIANS-S-1, the fluorescence intensity decreased rapidly by approximately 40%, and this fluorescence level was maintained during the steady state of ATP hydrolysis. As the substrate was used up, the fluorescence intensity increased to approximately 70% of the original value. These results together with model experiments with MIANS-N-acetylcysteine indicate that in the presence of ATP, the MIANS fluorophore attached to SH2 is located in a less hydrophobic environment than is the fluorophore in the absence of ligand and that the hydrolysis of ATP enhances hydrophobicity around the fluorophore. Acrylamide fluorescence quenching studies of MIANS-S-1 confirmed these results, indicating that addition of ATP and ADP to MIANS-S-1 results in an increase in the Stern-Volmer quenching constant of the fluorophore by factors of approximately 3 and 2.5, respectively. The present observations suggest that binding of ATP causes a movement of SH2 toward the protein surface, whereas it goes back into the protein interior after ATP hydrolysis. The results also confirmed previous observations by a chemical cross-linking approach (Hiratsuka, T. (1987) Biochemistry 26, 3168-3173).

Adenosine Diphosphate↗
PubMed1992

Spatial proximity of ATP-sensitive tryptophanyl residue(s) and Cys-697 in myosin ATPase.

The reactive thiol Cys-697 (SH2) in myosin ATPase was labeled with a fluorescent analog of maleimide, 2-(4'-maleimidylanilino)naphthalene-6-sulfonic acid (MIANS) (Hiratsuka, T. (1992) J. Biol. Chem. 267, 14941-14948). Although the tryptophan fluorescence of myosin subfragment-1 (S-1) was slightly affected by incorporation of the MIANS fluorophore, the tryptophan fluorescence of the resultant S-1 derivative (MIANS-S-1) was enhanced by ATP in a manner similar to that of unlabeled S-1. The quenching of tryptophan fluorescence of MIANS-S-1 was shown to result from a transfer of the excitation energy from tryptophanyl residue(s) to the MIANS fluorophore attached to SH2, which absorbed and fluoresced maximally at 325 and 418 nm, respectively. The energy transfer measurements were performed in the presence of acrylamide and compared to those performed in the absence of the quencher. The energy transfer efficiencies were found to be unaltered by acrylamide, indicating that the observed fluorescence energy transfer is originated exclusively from the tryptophanyl residue(s) that are not affected by acrylamide, i.e. the ATP-sensitive tryptophanyl residue(s) of S-1 (Torgerson, P. M. (1984) Biochemistry 23, 3002-3007). The distance between the tryptophanyl residue(s) and Cys-697 was calculated to be 27 A assuming a single donor-acceptor pair. Trp-510 is proposed to be one of the ATP-sensitive tryptophanyl residues.

Adenosine Diphosphate↗
PubMed1992

Serum secretory leukoprotease inhibitor levels to diagnose pneumonia in the elderly.

In pneumonia in the elderly, one occasionally encounters difficulties in evaluation with respect to both clinical observation and treatment. Thus a simple serum indicator is indicated. We measured secretory leukoprotease inhibitor (SLPI) concentrations in sera to see whether this can provide a useful indicator for pneumonia, especially in the elderly. Serum samples from patients over 65 yr of age, with (n = 54) or without (n = 87) pneumonia, and from healthy, young (n = 16) and aged (n = 188) control subjects were assayed using ELISA for human SLPI. Comparisons were made between groups with clinical diagnoses of either definite or probable pneumonia and among cases with various other respiratory diseases, including bronchial asthma, chronic obstructive pulmonary disease, and lung cancer. The mean SLPI concentration in patients with pneumonia was significantly higher than in patients without pneumonia or in healthy controls. The data suggest that the measurement of SLPI can provide a useful indicator for pneumonia to be used in clinical evaluation.

Aged↗
PubMed1992

[DNA typing of HLA-class II genes in idiopathic nephropathy].

The association between idiopathic nephropathy and HLA-class II antigen has been reported in many ethnic groups. We attempted to ascertain the HLA regions more specifically, associated with Japanese idiopathic membranous nephropathy (IMN), IgA nephropathy (IgAN) and minimal change nephrotic syndrome (MCNS), by examining HLA-class II genes. DNA typing of HLA-class II genes showed that IMN was associated with HLA-DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602, IgA with HLA-DQA1*0301, and MCNS with DQB1*0302. We also found a common epitope of HLA-class II (at 38th amino acid position of HLA-DR beta in IMN, at 55th of HLA-DQ beta in MCNS) in Japanese and Caucasian patients. These particular epitopes seem to be important for the susceptibility to IMN or MCNS.

DNA↗
PubMed1991

[A case of primary hypothyroidism with repeated episodes of respiratory failure].

A case of repeated episodes of hypoventilatory respiratory failure accompanied with primary hypothyroidism was reported. A 76-year-old woman was admitted to our hospital due to both disturbance of consciousness and respiratory failure. A diagnosis of primary hypothyroidism complicated with hypoventilatory respiratory failure deterioration due to respiratory infection was made. Supplemental therapy of thyroid hormones improved her general condition, but respiratory failure recurred after interruption of a replacement drug. Cases of unexplained respiratory failure should be differentiated from respiratory failure induced by hypothyroidism.

Aged↗
PubMed1990

Conformational changes in the 23-kilodalton NH2-terminal peptide segment of myosin ATPase associated with ATP hydrolysis.

A fluorophore, 9-anthroyl (AN) group, was covalently incorporated into the 23-kDa NH2-terminal peptide segment of myosin subfragment-1 (S-1) (Hiratsuka, T. (1989) J. Biol. Chem. 264, 18188-18194). The fluorescent S-1 derivative (AN-S-1) was utilized to detect conformational changes in the 23-kDa segment associated with ATP hydrolysis of S-1. The extrinsic fluorescence of AN-S-1 was sensitive to binding of ligands. Upon addition of adenyl-5'-yl-imidodiphosphate (AMP-PNP), pyrophosphate (PPi), and ADP, fluorescence of AN-S-1 decreased by 10, 34, and 50%, respectively. Using this fluorescence decrease, the number of ligand binding sites (n) and the dissociation constant (KD) for the binary complexes of AN-S-1 were obtained: n = 0.96, KD = 15 microM for AMP-PNP; n = 1.0, KD = 5.0 microM for PPi; n = 0.99, KD = 27 microM for ADP. When ATP was added to AN-S-1, the fluorescence intensity decreased rapidly by about 30%, and this fluorescence level was maintained during the steady state of ATP hydrolysis. As the substrate was used up, the fluorescence intensity decreased further to 50% of the original level. Model experiments with AN-N-acetylserine suggest that the fluorophore attached to S-1 is gradually exposed to more hydrophilic surface of protein with a progress of the ATPase reaction. The results indicate that conformational changes associated with ATP hydrolysis occur in the vicinity of the fluorophore attached to the 23-kDa NH2-terminal peptide segment of S-1.

Adenosine Diphosphate↗
PubMed1990

Transmission of ADP.vanadate-induced conformational changes to three peptide segments of myosin subfragment-1.

In order to study the conformational changes associated with formation of the stable ternary complex of myosin subfragment-1 (S-1) with ADP and orthovanadate (Vi), S-1 was fluorescently labeled with 9-anthroylnitrile, 4-fluoro-7-nitrobenz-2-oxa-1,3-diazole, and 5-(iodoacetamido) fluorescein at the 23-, 50-, and 20-kDa peptide segments of S-1, respectively (Hiratsuka, T. (1989) J. Biol. Chem. 264, 18188-18194; Hiratsuka, T. (1986) J. Biol. Chem. 261, 7294-7299; Takashi, R. (1979) Biochemistry 18, 5164-5169). The extrinsic fluorescence of these S-1 derivatives was sensitive not only to binding of ADP but to formation of the stable ternary complex with ADP and Vi. By using these fluorescent properties, the kinetics of formation of the stable ternary complexes of these S-1 derivatives with ADP and Vi, M. ADP.Vi, were analyzed according to the scheme proposed by Goodno (Goodno, C. C. (1979) Proc. Natl. Acad. Sci. U. S. A. 76, 2620-2624). [Formula; see text] The values obtained for KVi )0.2-0.4 mM) and k (0.03-0.05 s-1) of these S-1 derivatives were similar regardless of the peptide segments of S-1 where the fluorophore had been covalently labeled. These results suggest that the conformational changes, which are induced by formation of the stable ternary complex of S-1 with ADP and Vi, are transmitted to all three peptide segments of S-1 at a similar rate. The present results also encourage us to confirm that the ATPase site of S-1 resides at or near the region where all three peptide segments of S-1 are contiguous.

4-Chloro-7-nitrobenzofurazan↗
PubMed1990

Evidence for the existence of two equilibrium conformations of the ternary complex of myosin subfragment-1, ADP, and orthovanadate.

In order to investigate the flexibility of the ternary complex consisting of myosin subfragment-1 (S1), ADP, and orthovanadate (Vi), i.e., S1.ADP.Vi, the exchangeability of the bound ADP was examined. After isolation of the ternary complex of S1.ADP.Vi by gel filtration, 3'-O-(N-methylanthraniloyl)-ADP (Mant-ADP), a fluorescent analogue of ADP, was added at 0.5 degrees C. The added Mant-ADP was incorporated into the ternary complex very slowly by replacing the bound ADP. The nucleotide exchange occurred without regeneration of the ATPase activity of S1. Similarly, the ternary complex of S1.Mant-ADP.Vi prepared and isolated by gel filtration according to Hiratsuka (3, 4), was incubated with ADP (2.4 mM) at 4.5 degrees C. The nucleotide exchange of S1.Mant-ADP.Vi with ADP occurred in two phases with the apparent rates of 4.5 x 10(-4) s-1 (the fast phase) and 6.7 x 10(-6) s-1 (the slow phase). Biphasic exchange of the bound nucleotide was also observed with S1(A1) isozyme, indicating that the biphasic exchange did not correspond to two S1 isozymes. The apparent rates of the fast and the slow phases increased with the concentration of the added ADP, but they became saturated at an ADP concentration of the order of 2 mM, indicating that the nucleotide exchange reaction involves a step (or steps) which is insensitive to the concentration of free ADP in the solution. This step might be a reversible isomerization.

Adenosine Diphosphate↗