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Biomedical subjects

Y Sugimoto

Publications and source records attributed to Y Sugimoto.

At least 199 records · Page 11Linked to original sources
PubMed1998

Extensibility of the actin and myosin filaments in various states of skeletal muscle as studied by X-ray diffraction.

The effects of length changes applied to resting, contracting and rigor muscles on the reflection spacings of the X-ray diffraction patterns were summarized. The spacing changes of the actin- and myosin-based meridional reflections as a function of tension relative to an isometric tension of active muscle (P0) were linear and almost identical in the active and rigor states, showing that the extension of both filaments is Hookenian and does not depend upon the states of muscle. In addition to their length changes caused by tension generation, there are small but significant length changes of both filaments due purely to activation of muscle. The actin and myosin filaments are elongated by approximately 0.36% and approximately 0.43%, respectively under the maximum active tension. The results indicate that a large part of the sarcomere compliance of an active muscle is caused by the extensibility of the myofilaments. Inspection of the behavior of the meridional and layer-line reflection spacings reveals that there is a close relationship between the extensibility and helical twisting of the actin filaments under active and passive forces. The extension caused by tension is associated with an unwinding of right-handed helices following the actin monomers in the filament. At the pointed end of the filament could rotate anticlockwise through one fifth the complete turn during contraction.

Actins↗
PubMed1998

Structure of the monomeric actin-myosin head complex as revealed by X-ray solution scattering.

In order to study the structure of a complex of monomeric actin and myosin head (S1) in the presence of nucleotide, non-polymerizable G-actin was prepared by the reaction of G-actin with m-maleimidobenzoic acid N-hydroxysuccinimide ester (MBS) and diazonium(1H)tetrazole (DHT). Although singly-modified MBS-actin forms a 2:1 complex with S1, doubly-modified DHT/MBS-G-actin forms a 1:1 complex with a dissociation constant of approximately 10(-6) M and can activate Mg-ATPase of S1 by 2-fold. Using a synchrotron X-ray source, we have measured X-ray solution scattering from reversible acto-S1 complexes obtained by mixing rabbit skeletal S1 and DHT/MBS-G-actin in the absence of nucleotide or in the presence of MgADP. The Guinier plots of the scattering intensity showed straight lines indicating no large aggregates and gave the radii of gyration of the complexes to be 49 and 46 A in the absence and presence of ADP, respectively. The analysis of the scattering curves showed that a monomeric actin binds to a tip of S1, and that the complex undergoes substantial rearrangement resulting in a more compact structure when it binds ADP.

Actins↗
PubMed1998

Drug-selected complete restoration of superoxide generation in Epstein-Barr virus-transformed B cells from p47phox-deficient chronic granulomatous disease patients by using a bicistronic retrovirus vector encoding a human multi-drug resistance gene (MDR1) and the p47phox gene.

Chronic granulomatous disease (CGD) is a group of disorders characterized by the failure of phagocytes to produce superoxide. One-third of the cases of CGD in the USA and Europe results from defects in the gene encoding p47phox, a cytoplasmic component of NADPH oxidase for superoxide generation. In this study, we constructed the bicistronic retrovirus vector Ha-MDR-IRES-p47, which carries cDNAs for a human multi-drug-resistance gene (MDR1) and p47phox. The amphotropic retroviral producer cells were generated, and the supernatant of the producer cells was used to transduce Epstein-Barr virus-transformed B (EBV-B) cells, established from B cells of p47phox-deficient CGD patients, as an in vitro model of gene therapy for p47phox-deficient CGD. The transduced cells expressed both P-glycoprotein and p47phox protein, and the expression levels were increased after appropriate vincristine selection. The levels of superoxide production in the vincristine-selected cells were increased to a level similar to normal EBV-B cells. This result suggests that it is possible to achieve 100% correction of the CGD defect in p47phox-deficient EBV-B cells by using the bicistronic vector. This strategy could be employed not only in vitro, but also in vivo, in the gene therapy of a number of inherited diseases.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Effects of anxiolytics, diazepam and tandospirone, on immobilization stress-induced hyperglycemia in mice.

The benzodiazepine anxiolytic diazepam did not affect immobilization-elicited hyperglycemia, although a high dose increased blood glucose levels in normal mice. The serotonergic anxiolytic tandospirone reduced immobilization-induced hyperglycemia dose-dependently. Hyperglycemia elicited by immobilization stress was completely prevented by adrenalectomy but not by pretreatment with the corticosterone synthesis inhibitor dexamethasone. These results suggest that the effects of two anxiolytics, diazepam and tandospirone, on immobilization stress-induced hyperglycemia are quite different, although both drugs reduce anxiety. Furthermore, our results indicate that immobilization stress-elevated hyperglycemia is closely related to adrenaline release from the adrenal gland and that tandospirone may inhibit stress-induced hyperglycemia by modifying this mechanism.

Animals↗
PubMed1998

Role of isozyme group-specific sequence 4 in the isozyme-specific properties of human aldolase C.

To assess which regions of the aldolase C molecule are required for exhibiting isozyme-specific kinetic properties, we have constructed nine chimeric enzymes of human aldolases A and C. Kinetic studies of these chimeric enzymes revealed that aldolase C absolutely required its own isozyme group-specific sequences (IGS), particularly IGS-4, for exhibiting the characteristics of aldolase C which differ significantly from those of isozymes A and B (Kusakabe T, Motoki K, Hori K. Human aldolase C: characterization of the recombinant enzyme expressed in Escherichia coli. J Biochem (Tokyo) 1994;115:1172-7). Whereas human aldolases A and B required their own isozyme group-specific sequences-1 and -4 (IGS-1 and -4) as the main determinants of isozyme-specific kinetic properties (Motoki K, Kitajima Y, Hori K. Isozyme-specific modules on human aldolase A molecule. J Biol Chem 1993;268:1677-83; Kusakabe T, Motoki K, Sugimoto Y, Takasaki Y, Hori K. Human aldolase B: liver-specific properties of the isoenzyme depend on type B isozyme group-specific sequence. Prot. Eng. 1994;7:1387-93), the present studies indicate that the IGS-1 is principally substitutable between aldolases A and C. The kinetic data also suggests that the connector-2 (amino acid residues 243-306) may modulate the interaction of IGS units with the alpha/beta barrel of the aldolase molecule.

Amino Acid Sequence↗
PubMed1998

Strain differences in histamine release from peritoneal mast cells in rats.

1. Peritoneal mast cells from Brown-Norway (BN) rats were compared with those from Wistar and Sprague-Dawley (SD) rats. 2. Peritoneal mast cells from BN rats showed the smallest values in number, cell diameter and histamine contents compared with those from Wistar and SD rats. 3. BN rat peritoneal mast cells were more sensitive to compound 48/80 and anti-IgE than were those from Wistar and SD rats, and they showed a higher response to A23187 than did cells from Wistar rats. 4. The histamine release from passively sensitized peritoneal mast cells was weaker in BN rats than was that from Wistar and SD rats.

Animals↗
PubMed1998

Construction of a bovine yeast artificial chromosome (YAC) library.

We have constructed a bovine yeast artificial chromosome (YAC) library to provide a common resource for bovine genome research. We used leukocytes of a Japanese black bull (Bos taurus) as the DNA source, AB1380 for the yeast host, and pYAC4 for the vector. The library consists of 24,576 clones arranged in 256 96-well microtiter plates. An average insert size estimated from the analysis of 251 randomly selected clones was 480 kb. The rate of chimeric YACs evaluated by fluorescence in situ hybridization (FISH) analysis of 44 randomly selected clones was 36.4%. To estimate the number of genome equivalents, PCR-based screening was performed with 48 primer pairs and isolated 3.2 clones on average. In order to provide broad access for the scientific community, this library has been incorporated into the Reference Library system which provides high density filters for colony hybridization screening and a common database of the library.

Animals↗
PubMed1998

Toxic epidermal necrolysis with severe gastrointestinal mucosal cell death: a patient who excreted long tubes of dead intestinal epithelium.

TEN is a severe inflammatory disease which is characterized by generalized epithelial destruction. The epidermis is the most common target of TEN, however, any epithelium can be involved. We report a toxic epidermal necrolysis (TEN) patient who excreted long tubes of dead intestinal epithelium. Epidermal keratinocytes and intestinal epithelium were found to undergo extensive apoptosis by TUNEL method. Drugs were speculated as the causative agents for this case, the causative drug has not been identified. In contrast to marked improvement of cutaneous manifestation and hepatic function by methyl prednisolone pulse therapy, the gastrointestinal symptoms did not respond to therapies, and the patient died by heart failure. Present case suggested a pathogenetic mechanism targeting antigens commonly expressed on the gastrointestinal epithelium and epidermis.

Fatal Outcome↗
PubMed1998

Report of the first workshop on the genetic map of bovine chromosome 1.

A report of the first workshop on the genetic map of bovine chromosome 1 (BTA1) is presented. Five laboratories contributed 31,962 informative meioses from 70 loci. Thirty-two loci which had been typed by at least two laboratories were used to construct a framework genetic map with a likelihood ratio support of at least 1000:1 for locus order. The resulting sex-averaged framework map contained 26 loci and spanned 163.6 CM. The lengths of the female and male maps were 159.5 CM and 165.3 CM, respectively, and there was evidence for an expansion in the telomeric one-third of the male map. Of the four cases where order for closely linked loci differed among the maps produced for each of the contributing laboratories, a consensus order was obtained for three in the framework map. The average genetic distance between framework loci on the sex-averaged map was 6.3 CM.

Animals↗
PubMed1998

Clinical efficacy of the FLUTTER device for airway mucus clearance in patients with diffuse panbronchiolitis.

Expectoration of mucus is important in preventing the development of airway inflammation in patients with diffuse panbronchiolitis (DPB). To evaluate the clinical efficacy of the FLUTTER device in clearing mucus from the airways of patients with DPB who have difficulty expectorating, we assessed pulmonary function and symptoms in patients treated with FLUTTER. Eight patients in a stable clinical condition with DPB were included in the study. The study was divided into two consecutive, 1-week periods. The initial week was an observation week. During the following week, patients used FLUTTER four times daily. Expectorated sputum was collected in a container and weighed every day during 2 weeks. Pulmonary function, partial oxygen pressure and partial carbon dioxide pressure in arterial blood were measured in all patients on the last day of the observation week and the FLUTTER treatment week. A symptom score for difficulty of expectoration was determined by questionnaire. A pneumothorax developed in one patient during using FLUTTER. The mean daily sputum weight and peak expiratory flow rate increased significantly after treatment with FLUTTER ( P< 0.04 and P< 0.02, respectively). Symptom score improved significantly after using FLUTTER ( P< 0.02). We conclude that the use of FLUTTER is effective in clearing mucus from the airways. However, the development of a pneumothorax may complicate use of the procedure in some cases.

Adult↗
PubMed1998

[Epidemiological study on penicillin-resistant Streptococcus pneumoniae].

We studied the differences among clinical isolates of Penicillin-resistant Streptococcus pneumoniae by polymerase chain reaction (PCR) of pbp2b gene, followed by serotyping and pulsed field gel electrophoresis (PFGE) analysis. Clinical isolates were recovered from sputum samples from patients with respiratory infection in Tottori University Hospital between June 1986 and May 1996. By PCR, altered pbp2b genes of the resistant isolates were detected in 76.5%. The percentages of the isolates that had altered pbp2b genes increased concomitantly with the minimum inhibitory concentration (MIC). By serotyping the percentage of 19F, 23F, 6B and 14 was 54.5%, 18.2%, 9.1% and 9.1% respectively. The frequency of isolates resistant to penicillin increased rapidly from 1991 in this hospital and most isolates belonged to serotype 19F. The resistant isolates in this hospital and 4 clinical resistant isolates of S. pneumoniae 19F in a second hospital were studied by PFGE. 14 of 18 resistant 19F isolates in this hospital and all 19F isolates from the second hospital presented an identical pattern. The remaining 4 samples were similar though not completely identical. These results indicate that the penicillin resistant 19F isolates have a common clonal origin and have spread rapidly from 1991 in this hospital.

Genes, Bacterial↗
PubMed1998

Characterization of ASK mice, a strain highly sensitive to anaphylactic shock.

A mouse strain named ASK that was originally isolated from El (epilepsy) mice has been shown to be highly sensitive to anaphylactic shock. Here, we characterized the bases of the sensitivity of ASK mice in comparison with the parental strain, El. More than 90% of ASK mice, but not El mice that had been sensitized either actively or passively, died within 1 h following an antigen challenge. The anaphylactic death was effectively blocked by diphenhydramine. Plasma histamine levels increased by 30-50 fold in ASK after the antigen challenge, but only a 2-3-fold increase was observed in El mice. All (El x ASK) F1 mice, either male or female, showed an ASK-like phenotype, suggesting that the impaired plasma histamine response in El mice is due to some recessive mutation(s). Consistent with the plasma histamine responses, cultured mast cells derived from El bone marrow showed impaired potency to degranulate in response to surface IgE engagement, in contrast to ASK mast cells which undergo normal degranulation. Another characteristic feature of ASK mice is their sensitivity to histamine, since 75% of the mice were killed by the subcutaneous administration of 100-200 mg/kg histamine, while C3H and BALB/c mice were resistant to even 600 mg/kg histamine. Taken together, the major bases of the susceptibility to anaphylactic shock in ASK mice are thought to be the enhanced sensitivity to histamine and the recovered degranulation machinery in mast cells that is impaired in El mice.

Anaphylaxis↗
PubMed1998

Moyamoya disease associated with pulmonary sarcoidosis--case report.

A 61-year-old female presented with a unique case of moyamoya disease associated with pulmonary sarcoidosis. She was admitted for sudden onset of left temporalgia with episode of numbness on face, tongue, and upper extremity on the right side. The next morning, she had symptoms of Gerstmann syndrome and her ability to speak was disturbed. Her medical history included radical resection of lung cancer on the right side. She had no symptoms of pulmonary sarcoidosis. Neuroimaging showed an infarction in the left occipital lobe. Angiography showed occlusions of the bilateral internal carotid arteries at the supraclinoid portions. Subsequently, a left superficial temporal artery-middle cerebral artery anastomosis with encephalo-myo-synangiosis was performed. Ninety-three days after admission, she suddenly developed dyspnea which resulted in death 3 hours later. Autopsy findings showed typical epithelioid granulomas of sarcoid type in the lymph nodes of the peribronchus, lung, and liver. Thrombotic emboli were found in the bilateral pulmonary arteries, and marked fibrous intimal thickening in the bilateral internal carotid arteries. Immunological reaction with inflammatory events may cause pathological changes in patients with moyamoya disease or sarcoidosis. The co-incidence in this case suggests that some common inflammatory events may be involved in the pathogenesis of these diseases.

Carotid Artery, Internal↗
PubMed1998

Preparation and characterization of micellar calcium phosphate-casein phosphopeptide complex.

Micellar calcium phosphate (MCP) in bovine milk was separated as the complex with casein phosphopeptide (CPP) by the following procedures. Rennet curd obtained from skim milk was suspended in water, the pH was adjusted to 4.6, and the suspension was centrifuged at 1,000 x g. CPP was separated from the precipitated casein by tryptic hydrolysis and ethanol precipitation. The supernatant, which contained calcium and inorganic phosphate liberated from casein micelles by acidification, and CPP were mixed; the pH was adjusted to 6.7; and then the solution was lyophilized. From 1 L of skim milk, 3.16 g of the MCP-CPP complex was obtained. The dried MCP-CPP complex was easily dissolved in water and contained 12.7% calcium, 0.3% magnesium, 3.4% inorganic phosphorous, and 2.2% organic phosphorous. No crystal structure of hydroxyapatite was shown in the MCP-CPP complex by the X-ray diffraction analysis, although the pattern of NaCl crystal was observed. The X-ray diffraction pattern of commercial whey mineral, which was prepared by precipitation at alkaline pH from rennet whey, was similar to that of hydroxyapatite. It was confirmed by high-performance gel chromatographic analysis that the form of calcium phosphate in the MCP-CPP complex was similar to that of casein micelles. The MCP-CPP complex was also separated from commercial rennet casein. The method for the separation of MCP-CPP complex described above can be applied to the large-scale preparation.

Animals↗
PubMed1998

Black tea theaflavins induce programmed cell death in cultured human stomach cancer cells.

The exposure of human stomach cancer KATO III cells to black tea theaflavin extract, free theaflavin, and theaflavin digallate that are main components of the extract, led to both growth inhibition and the induction of programmed cell death (apoptosis). Morphological changes showing apoptotic bodies were observed in the cells treated with black tea theaflavin extract, theaflavin and theaflavin digallate. The fragmentations by these theaflavin compounds of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis were observed to be concentration- and time-dependent. These data suggest that drinking of black tea in large amounts is recommended to protect humans from stomach cancer.

Apoptosis↗
PubMed1998

Alteration of the CDKN2A gene in pancreatic cancers: Is it a late event in the progression of pancreatic cancer?

Various genetic changes are involved in progression of various cancers. We examined alterations (deletion, sequence abnormalities, methylation) of the CDKN2A gene in cell lines and tumor tissues of pancreatic cancers. Some alterations of this gene were found in all the 12 cell lines examined. In the primary lesions of pancreatic cancers, homozygous or hemizygous deletion were found in 8 of 24 ductal carcinoma and 4 of 9 other types of carcinomas. It appears that there is an association between the alteration of this gene and tumor size, regional lymph node metastasis and hematogenous distant metastasis in the ductal carcinoma, but not in the other types of carcinomas. All the 5 liver metastatic lesions of the ductal carcinoma examined revealed homozygous or hemizygous deletion and 3 bp deletion. These results suggest that inactivation of the CDKN2A gene occurs more frequently in cell lines than in pancreatic cancer tissues. Such genetic events on the CDKN2A gene may play an important role possibly at a later step in the progression of pancreatic ductal carcinoma.

Adult↗