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Biomedical subjects

K Ogata

Publications and source records attributed to K Ogata.

At least 91 records · Page 5Linked to original sources
PubMed1999

Shape and energetics of a cavity in c-Myb probed by natural and non-natural amino acid mutations.

The shape and the energetics of a functional cavity in the R2 subdomain (90-141) of the c-Myb DNA-binding domain were investigated by spectroscopy and thermodynamic analysis. We focused on the valine 103 residue located in front of the cavity. Nine mutants, in which valine 103 was substituted with alanine, 2-aminobutyric acid, norvaline, norleucine, leucine, isoleucine, allo -isoleucine, cyclohexylglycine, and cyclohexylalanine, were chemically synthesized and analyzed. These mutants provided a wide distribution of sizes which ranged from forming additional cavity space to filling and overflowing the cavity space. Temperature-scanning circular dichroism measurements and differential scanning calorimetry revealed a linear relationship between the van't Hoff enthalpy and the thermal transition temperature for the cavity-filling mutations. On the other hand, the mutants with side-chains larger than the side-chain of leucine resulted in a relatively low transition enthalpy and temperature, most likely due to the exposure of the side-chain to solvent and the increase in the entropy of the folded states. Branching at the beta-carbon atom reduced the unfolding free energy due to the steric constraint in the cavity. In particular, the mutational elongation of the side-chain from beta-carbon to the trans -to-CO direction proved to be more hindered than that from beta-carbon to the trans -to-NH. The unfolding free energy versus side-chain volume formed a bell-shaped plot with a maximum free energy for the leucine mutant. The difference in the transition free energy for cavity-filling mutants with beta-unbranched side-chains were two to four times larger than the difference in the transfer energy from organic solvent to water. Therefore, the increase in unfolding free energy would most likely be attributed to van der Waals interactions in the cavity wall, which would be a origin of stabilization by the sliding of tryptophan 95 into the cavity upon DNA binding.

Amino Acid Sequence↗
PubMed1999

Intramuscular spindle cell hemangioendothelioma.

Spindle cell hemangioendothelioma occurring in skeletal muscle is extremely rare. No reported studies have performed an imaging evaluation of intramuscular spindle cell hemangioendothelioma. We report on such a tumor arising in an unusual site, the right extensor digiti minimi, in a 46-year-old woman. An en bloc resection was performed and the patient has been disease free for 8 years. Radiologic imaging in the present case showed similar findings to those described in intramuscular hemangioma.

Female↗
PubMed1999

Intraoperative limb length measurement in total hip arthroplasty.

In order to evaluate the efficacy of intraoperative measurement of limb length inequality (LLI), we performed a prospective study on 64 patients who underwent unilateral total hip arthroplasty. The patients were divided into 2 groups. In Group I, the LLI was evaluated by the Shuck test, and in Group II by intraoperative measurement using a Steinman pin and an adjustable caliper. Preoperative LLIs assessed on radiographs averaged 1.18 cm in Group I and 0.37 cm in Group II.

Aged↗
PubMed1999

Blood flow of the gluteus medius muscle. An animal study.

We investigated the effects of subperiosteal dissection on blood flow in the gluteal medius muscle in adult rabbits using the hydrogen washout technique. After the control blood-flow rate was determined, 8 rabbits were separated into 2 groups according to the direction of the dissection. The gluteal medius muscle was dissected from the iliac crest in the proximal-distal direction in 10 hips. In another 6 hips, the greater trochanter was osteomised and the gluteus medius muscle was dissected from the ilium in the distal-proximal direction. Dissection of the middle third of the gluteus medius muscle caused the most significant reduction in blood flow, more than 50% in both groups. This result indicates that minimising damage to the mid-portion of the gluteus medius muscle is important for reducing the incidence of post-operative complications.

Angiography↗
PubMed1999

Sequence analysis of small cryptic plasmids isolated from Selenomonas ruminantium S20.

Two small cryptic plasmids designated pONE429 and pONE430 were isolated from a rumen bacterium, Selenomonas ruminantium S20. The complete sequence of pONE429 was 2100 bp and contained one open reading frame (ORF) of 201 amino acids. The sequence of pONE430 had 1527 bp and one ORF of 171 amino acids with the similarity of replication protein (Rep protein) of pOM1, pSN2, and pIM13 isolated from Butyrivibrio fibrisolvens, Staphylococcus aureus, and Bacillus subtilis, respectively. In these plasmids, the upstream nucleotide sequence of Rep protein had the conserved nucleotides which could be double-strand origin (DSO) of rolling circle replication (RCR) mechanism. The plasmids of pONE429, pONE430, pJJMI, pJDB21, and pS23 were isolated from S. ruminantium strains and had similar regions that were located within a <450-bp nucleotide. These similar regions may be the location that was recognized by the host strain, S. ruminantium.

Amino Acid Sequence↗
PubMed1999

Construction of Prevotella ruminicola-Escherichia coli shuttle vector pRAM45 and transformation of P. ruminicola strains by electroporation.

A new plasmid shuttle vector, pRAM45, was constructed from the Escherichia coli plasmid pACYC184 and the cryptic plasmid pRAM4, which was originally isolated by us from Prevotella ruminicola T31 (Ogata et al., Plasmid, 35, 91-97, 1996). The vector was electrotransformed into different P. ruminicola strains. Polymerase chain reaction and Southern hybridization experiments confirmed its integrity in P. ruminicola transformants.

Journal Article↗
PubMed1999

Corticosteroid treatment of prolidase deficiency skin lesions by inhibiting iminodipeptide-primed neutrophil superoxide generation.

We studied the pathogenetic role of iminodipeptides, and the effects of corticosteroids on the skin lesions of two adult female siblings with prolidase deficiency. The elder sister had had severe skin ulcers and mental retardation since childhood, while the younger sister had shown milder clinical manifestations since late adolescence. The ulcers showed vascular wall thickening and neutrophil infiltration. Oral prednisolone at moderate doses was not effective, but corticosteroid pulse therapy followed by a moderate dose of prednisolone improved the preulcerative indurated lesions and ulcers. A 2-year follow-up of the younger patient indicated that N-formyl methionyl leucyl phenylalanine-induced neutrophil superoxide generation was elevated, in parallel with an increase in the serum iminodipeptide level, when the skin ulcers and preulcerative indurated lesions were most active. Corticosteroid pulse therapy downregulated the superoxide generation by neutrophils. The serum iminodipeptide level, however, did not decrease during 25 days after pulse therapy. These findings suggest that iminodipeptides may play an important part in aggravating the skin lesions by priming neutrophil superoxide generation, and that high-dose corticosteroids improve the skin lesions, probably by inhibiting the infiltration, and superoxide generation by, neutrophils. Neutrophil superoxide generation was more prominent in the elder sister, suggesting that clinical severity may depend on the response of neutrophils to the iminodipeptides. Chronic stimulation by superoxide may cause thickening of cerebral blood vessels and eventual mental retardation.

Adult↗
PubMed1999

Aeromonas sobria infection with severe soft tissue damage and segmental necrotizing gastroenteritis in a patient with alcoholic liver cirrhosis.

A 49-year-old man, who had a 3-year history of liver dysfunction but had not been treated, was admitted to the hospital with a sudden onset of fever and generalized muscle pain. He subsequently developed generalized purpura with scattered hemorrhagic bullae of the skin and massive bloody stools. Aeromonas sobria was proven by culture of both blood and bullous fluid. In spite of the extensive treatment with antibiotics and other medications in the intensive care unit (ICU), the patient went into septic shock and died 2 days after admission. Pathological examination on autopsy revealed segmental necrotizing gastroenteritis with bacterial colonies and alcoholic liver cirrhosis, in addition to extensive severe soft tissue damage involving cellulitis and rhabdomyolysis and epidermolysis. Although the prognosis for Vibrio vulnificus infection with severe soft tissue damage in patients with liver cirrhosis, malignancy, diabetes mellitus or other pre-existing diseases is poor, the unfavorable progression of Aeromonas species, especially A. sobria infection is rare. This is thought to be the first report of an autopsied case.

Aeromonas↗
PubMed1999

Roles of asp126 and asp156 in the enzyme function of sphingomyelinase from Bacillus cereus.

To elucidate the roles of conserved Asp residues of Bacillus cereus sphingomyelinase (SMase) in the kinetic and binding properties of the enzyme toward various substrates and Mg2+, the kinetic data on mutant SMases (D126G and D156G) were compared with those of wild type (WT) enzyme. The stereoselectivity of the enzyme in the hydrolysis of monodispersed short-chain sphingomyelin (SM) analogs and the binding of Mg2+ to the enzyme were not affected by the replacement of Asp126 or Asp156. The pH-dependence curves of kinetic parameters (1/Km and kcat) for D156G-catalyzed hydrolysis of micellar SM mixed with Triton X-100 (1:10) and of micellar 2-hexadecanoylamino-4-nitrophenylphosphocholine (HNP) were similar in shape to those for WT enzyme-catalyzed hydrolysis. On the other hand, the curves for D126G lacked the transition observed for D156G and WT enzymes. Comparison of the values and the shape of pH-dependence curves of kinetic parameters indicated that Asp126 of WT SMase enhances the enzyme's catalytic activity toward both substrates and its binding of HNP but not SM. The deprotonation of Asp126 enhances the substrate binding and slightly suppresses the catalytic activity toward both substrates. Asp156 of WT SMase acts to decrease the binding of both substrates and the catalytic activity to HNP but not SM. From the present study and the predicted three-dimensional structure of B. cereus SMase, Asp126 was thought to be located close to the active site, and its ionization was shown to affect the catalytic activity and substrate binding.

Aspartic Acid↗
PubMed1999

Lambert-Eaton myasthenic syndrome associated with idiopathic thrombocytopenic purpura and diffuse panbronchiolitis: long-term remission after a course of intravenous immunoglobulin combined with low-dose prednisolone.

We report a case of Lambert-Eaton myasthenic syndrome (LEMS) associated with idiopathic thrombocytopenic purpura (ITP) and diffuse panbronchiolitis (DPB). An extensive search for malignancy yielded negative results. Interestingly, ITP and DPB developed simultaneously when the patient suffered from myasthenic symptoms. This is the first report in the Japanese or English literature of an association of LEMS, ITP, and DPB. The use of cholinesterase blocker alone did not improve the myasthenic symptoms, and the symptoms and signs relapsed with the tapering of prednisolone (PSL) dosage. However, after administration of immunoglobulin (IVIG) (0.4 g/kg/day x 5 days), low-dose PSL (20 mg/day) alleviated the LEMS and ITP, and the diseases have remained in remission for 8 months without additional IVIG. We suspect that there is a synergistic relationship between IVIG and PSL.

Anti-Inflammatory Agents↗
PubMed1999

Crystallization and preliminary X-ray analysis of wild-type and V103L mutant Myb R2 DNA-binding domain.

The R2 subdomain of the mouse c-Myb DNA-binding domain and its V103L mutant have been crystallized by the vapour-diffusion method using highly concentrated sodium citrate at pH 6.8 as a precipitant. Using ammonium sulfate as precipitant in MES buffer only produced crystals for the mutant R2. All crystals are isomorphous and belong to space group P212121. The unit-cell dimensions for wild-type R2 crystals grown from sodium citrate precipitant are a = 28.83, b = 40.18, c = 49.23 A. Crystals contain one R2 molecule per asymmetric unit. They are stable during 3 d exposure to X-rays and diffract to 1.37-1.45 A resolution.

Animals↗
PubMed1999

Successful treatment of adolescent pemphigus vulgaris by immunoadsorption method.

A 15-year-old girl with pemphigus vulgaris did not respond to oral administration of prednisolone at 45 mg/day. The skin and oral mucous membrane lesions recurred after effective treatments with methylprednisolone pulse therapy and combination therapy with prednisolone and cyclosporine. The finally successful treatment involved eleven cycles of immunoadsorption using a tryptophan column and administration of a moderate dose of prednisolone. Serum gamma-globulin level and anti-intercellular antibody titer decreased from 1.08 g/dl to 0.5 g/dl and 1:320 to 1:20, respectively. She has been well controlled with 21.5 mg/day prednisolone for 8 months after the final adsorption. Considering the physical, mental and social situation of adolescent student patients, immunoadsorption is a highly preferable choice among a variety of treatment modalities for pemphigus vulgaris because it makes the term of hospitalization shorter and avoids undesirable side effects from initial high dose corticosteroids.

Adolescent↗
PubMed1999

[Outbreak case caused by different colicin type of Shigella sonnei in a day nursery in Tokyo (1998)].

From October through December, 1998, person to person infection caused by Shigella sonnei had occurred in the day nursery in Hachioji-city Tokyo, and a total of 41 patients including 3 suspected cases and 3 carriers had been confirmed. Although one case was imported case which is one-year-old kindergarten child, the remaining was domestic case. Of patients, 33 cases (80.5%) were a three-year-old kindergarten children and their families, accounting for 20 and 13 cases, respectively. From the data of symptom onset of patients, epidemic could distinguish to the former part and the later part. The recur or reinfection, and re-detection case was observed in the later part. Clinical symptom of the patients was diarrhea (100%), fever (80%) and abdominal cramps (70%), and LVFX for adult or FOM for child was used for the therapy. In the colicin typing test and the antibiotic susceptibility test for 9 reagents, almost isolates in the former part were type 0 and susceptible, and MBC for FOM ranged from 6.25 to 100 micrograms/ml, whereas those in the later part was type 2 and resistant for the TC, and showed highly MBC for FOM with 50 or 100 micrograms/ml. However, both isolates showed same patterns in plasmid profiles and DNA fingerprints by RAPD analysis. On the other hand, the strain from imported case was also colicin 0, but it was different as regards resistant for ABPC and ST and two genetic analysis.

Adult↗
PubMed1999

S-(1,2-Dicarboxyethyl)glutathione in yeast: partial purification of its synthesizing enzyme.

S-(1,2-Dicarboxyethyl)glutathione (DCE-GS) was found in Saccharomyces cerevisiae, but not in bacterial species nor in a unicellular alga (Acetabularia acetabulum). The enzyme that catalyzes condensation of L-malate and glutathione (GSH) to form DCE-GS was partially purified from baker's yeast. It had a molecular mass of 49 kDa and was monomeric and the Km values were 2.2 and 1.4 mM for L-malate and GSH, respectively. The enzyme had a pH optimum of 7.5. DCE-GS levels in yeast cells were significantly higher in aerobic cultures than in anaerobic ones. DCE-GS was synthesized in cells cultured between 20 and 35 degrees C.

Acetabularia↗
PubMed1999

Constructing a local district telepathology network in Japan. Diagnosis of intraoperative frozen sections via telepathology over an integrated service digital network and the National Television Standard Committee System.

OBJECTIVE: To construct a local telepathology network between the Department of Pathology, Tohoku University Hospital, and Koritu Kesennuma Hospital, about 150 km away. STUDY DESIGN: Tohoku University Hospital is connected with Koritu Kesennuma Hospital by an integrated service digital network for telepathology using the National Television Standard Committee system. The cases submitted for telepathology were limited to those in which a rapid intraoperative diagnosis was made on frozen sections. RESULTS: At this writing, more than 200 cases were diagnosed during a period of 2.5 years. The cases submitted increased with time, amounting to 150 in 1996. In some cases the use of telepathology proved to be fairly advantageous. For example, in one case a radical operation was avoided because of a diagnosis on intraoperative frozen sections. DISCUSSION: There are problems to be solved before telepathology becomes available for practical use: (1) misdiagnosis due to poor quality of instruments, including the transmission cable and pictures; (2) cost-benefit ratio, (3) protection of patients' privacy, and (4) overwork for pathologists. The Japanese government will officially accept telepathology as a means of medical examination in the future. Despite some problems left, telepathology is a promising technology.

Adenoma, Bile Duct↗