Biomedical subjects

Shigeru Miyata

Publications and source records attributed to Shigeru Miyata.

14 recordsLinked to original sources

PubMed2006

[Optimum preparation of levocarnitine chloride solution in the hospital pharmacy].

Levocarnitine chloride is used for the therapeutic purpose of levocarnitine deficiency. For infants, however, levocarnitine chloride tablets must be crushed to avoid difficulties associated with swallowing, and also to administer an appropriately low dosage. Since the tablet is extremely hygroscopic and sour, it is dissolved in water containing simple syrup after crushing. In this study we investigated the stability of the drug after dissolution to optimize its preparation for clinical use. It was shown to be stable for at least 90 days after preparation, and microbes did not grow in 1-10% (w/v) solutions (pH 2.0-2.5) regardless of the presence or absence of simple syrup. Furthermore, the autoclaved levocarnitine chloride solution was as stable as the non-autoclaved one. In conclusion, the method employed in our hospital for the preparation of levocarnitine chloride for infants is appropriate and is recommended as a standard medicine supply method among different facilities.

Carnitine↗

PubMed2005

Changes in ganglioside content affect the binding of Clostridium perfringens epsilon-toxin to detergent-resistant membranes of Madin-Darby canine kidney cells.

Epsilon-toxin (ET) of Clostridium perfringens, which causes fatal enterotoxemia in ungulates, was previously shown to bind to and form a heptameric pore within the detergent-resistant membranes (DRMs) of MDCK cells. Depletion of cholesterol has also been shown to decrease the cytotoxicity of ET and its heptamerization. In this study, we investigated the effects of changes in sphingolipids, other DRM components of MDCK cells, on the cells' susceptibility to ET. Treatment with fumonisin B1 and PDMP, inhibitors of sphingolipid and glycosphingolipid syntheses, respectively, increased the susceptibility, while D609, a sphingomyelin synthesis inhibitor, had the opposite effect. The exogenous addition of ganglioside G(M1) dramatically decreased the ET binding, heptamerization and cytotoxicity. These effects were shown not to be due to ET binding to G(M1) or to denaturation of ET. We also found that the ET cytotoxicity towards MDCK cells decreased with an increase in culture time. In accordance with the resistance observed for prolonged cultured cells, G(M3), a major ganglioside component, increased and sialidase treatment increased their susceptibility. These results suggest that membrane-anchored sialic acid of G(M3) within DRMs inhibits ET binding, leading to prevention of the heptamerization of ET and cell death. It is also suggested that sialidase produced by this organism aids the targeting of ET to MDCK cells.

Animals↗

PubMed2004

CD4+ T cells migrate from airway to bone marrow after antigen inhalation in rats.

BACKGROUND: IL-5-producing T lymphocytes increase in rat bone marrow after inhalational challenge with allergen. OBJECTIVE: To test the hypothesis that T cells migrate from the airways to the marrow, we examined the trafficking of T cells in Brown Norway rats after sensitization and challenge with ovalbumin. METHODS: Purified CD4+ T cells, harvested from cervical lymph nodes of naive and ovalbumin-sensitized donors, were labeled with carboxy fluorescein diacetate succinimidyl ester; 20 x 10(6) cells were placed in the trachea of naive or sensitized recipients under anesthesia, and 18 hours later, animals were challenged with inhaled ovalbumin. Cells were harvested 24 hours later from the bone marrow, bronchoalveolar lavage fluid, lungs, the lung blood pool of cells, lung draining lymph nodes, peripheral blood, and spleen. RESULTS: The number of carboxy fluorescein diacetate succinimidyl ester-positive cells, measured by fluorescence-activated cell sorter, in the bone marrow of ovalbumin sensitized, primed T-cell recipients was higher than either the sham-sensitized, primed T-cell recipients or sham-sensitized, naive T-cell recipients (P < .05). The number of eosinophils in both bone marrow and bronchoalveolar lavage fluid was increased in ovalbumin-sensitized, primed T-cell recipients. The expression of the T-cell chemoattractants eotaxin and IL-16, evaluated by immunohistochemistry, was higher in the bone marrow of ovalbumin-sensitized, primed T-cell recipients. CONCLUSIONS: CD4+ T cells travel from airway to bone marrow after antigen inhalation. The homing of the CD4+ T cells might be facilitated by eotaxin and IL-16 expression in the bone marrow and might contribute to the stimulation of eosinophilopoiesis after airway allergen exposure.

Administration, Inhalation↗

PubMed2004

High-level expression of clostridial sialidase using a ferredoxin gene promoter-based plasmid.

A "large" sialidase isozyme (NanI) from Clostridium perfringens is a representative microbial sialidase with broad substrate specificity, being used for the analysis of sialoglycoconjugates. It is also a possible virulence factor. However, purification of the native enzyme in a large quantity is not practical due to its low productivity. To obtain the enzyme in a satisfactory yield, a gene encoding the NanI was transcriptionally fused to the fdx gene promoter (P(fdx)) in a shuttle-vector, pFF, and transformed into C. perfringens 13. The resultant strain released the enzyme into the culture medium, as the original strain does. The enzyme activity increased during the first 6 h of culture and thereafter remained at maximal levels. The maximal activity was approximately 3000-fold compared with that of the original strain, and 15-fold compared with that of recombinant Escherichia coli, which possesses extra copies of the tRNA gene for selected rare codons. This suggests the usefulness of a P(fdx)-based plasmid for expressing AT-rich genes in C. perfringens. The enzyme was successfully purified by two-step procedure with a specific activity of 2860 U/mg using 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid and a yield of 1.69 mg of NanI per 100 ml of culture. The method described here can facilitate purification of NanI in enough quality and quantity to analyze the role of sialoglycoconjugates in cells and the pathogenic importance of NanI sialidase.

Base Sequence↗

PubMed2004

[A case of tricuspid valve infective endocarditis presenting with multiple nodular shadows in both lungs without known predisposing factors].

A 56-year-old woman was admitted to our hospital with fever, cough, and sputum production. Her chest radiograph and chest computed tomography showed multiple nodules. Laboratory findings revealed leukocytosis and an increased C-reactive protein concentration. Physical examination revealed a systolic murmur. Transesophageal echocardiography demonstrated a 1.5-cm area of vegetation on the tricuspid valve. Blood cultures grew Staphylococcus aureus. Tricuspid valve endocarditis and septic pulmonary embolism were diagnosed. She was treated successfully with intravenous ampicillin/sulbactam. This was a rare case of tricuspid valve infective endocarditis in an adult patient without known predisposing factors.

Ampicillin↗

PubMed2003

A novel type of DNA curvature present in a Clostridium perfringens ferredoxin gene: characterization and role in gene expression.

This study has revealed that a Clostridium perfringens ferredoxin gene (per-fdx) possesses a novel type of DNA curvature, which is formed by five phased A-tracts extending from upstream to downstream of the -35 region. The three A-tracts upstream of the promoter and the two within the promoter are located at the positions corresponding to A-tracts present in a C. perfringens phospholipase C gene (plc) and a Clostridium pasteurianum ferredoxin gene (pas-fdx), respectively. DNA fragments of the per-fdx, pas-fdx and plc genes (nucleotide positions -69 to +1 relative to the transcription initiation site) were fused to a chloramphenicol acetyltransferase reporter gene on a plasmid, pPSV, and their in vivo promoter activities were examined by assaying the chloramphenicol acetyltransferase activity of each C. perfringens transformant. Comparison of the three constructs showed that the order of promoter activity is, in descending order, per-fdx, pas-fdx and plc. Deletion of the three upstream A-tracts of the per-fdx gene drastically decreased the promoter activity, as demonstrated previously for the plc promoter. Substitution of the most downstream A-tract decreased the promoter activities of the per-fdx and pas-fdx genes. These results indicate that not only the phased A-tracts upstream of the promoter but also those within the promoter stimulate the promoter activity, and suggest that the high activity of the per-fdx promoter is due to the combined effects of these two types of A-tracts.

Amino Acid Sequence↗

PubMed2003

Accumulation of Clostridium perfringens epsilon-toxin in the mouse kidney and its possible biological significance.

In this paper we show that Clostridium perfringens epsilon-toxin accumulates predominantly in the mouse kidney, where it is distributed mainly in glomeruli, capillaries, and collecting ducts. Although some pycnotic and exfoliated epithelial cells were observed in distal tubuli and collecting ducts, there were no findings indicative of severe renal injury. Bilateral nephrectomy increased the mouse lethality of the toxin, suggesting that the kidney contributes to the host defense against the lethal toxicity of epsilon-toxin.

Animals↗

PubMed2003

Allergic bronchial asthma: airway inflammation and hyperresponsiveness.

The international consensus report on diagnosis and treatment of asthma was published in 1992 (Clin Exp Allergy 22: 1-72). According to the report, asthma is a chronic inflammatory disorder of the airways in which many cells play a role, including mast cells and eosinophils. Airway inflammation causes various symptoms of asthma which are usually associated with widespread but variable airflow obstruction and causes an associated increase in airway responsiveness to a variety of stimuli. The definition of asthma, provided in this report, is an epoch-making revision of the conventional recognition of asthma based on respiratory physiology and does not contradict the empirical knowledge that asthma responds well to steroid therapy. One reason, which led airway inflammation to be understood as a major factor in the pathophysiology of asthma is the technological advance and the widespread use of bronchoscopes. The use of bronchoscopy as a research tool has markedly improved the understanding of the pathology of asthma. It became also possible to link biopsy findings to autopsy findings in patients who died of asthma. However, it is relatively difficult to repeat a biopsy of the airway mucosal membranes in individual asthmatic patients. Here, animal models of asthma play a significant role. Findings from animal models can provide a clue for the development of new anti-asthmatic drugs. This paper will deal with the paradigm of allergic asthma and focus on recent topics of interleukin (IL)-4 and IL-5, which seem to play a central role in allergic asthma. The causative relationship between airway inflammation and hyperresponsiveness will be discussed.

Airway Obstruction↗

PubMed2002

Clostridium perfringens epsilon-toxin forms a heptameric pore within the detergent-insoluble microdomains of Madin-Darby canine kidney cells and rat synaptosomes.

Clostridium perfringens epsilon-toxin, which is responsible for enterotoxaemia in ungulates, forms a heptamer in rat synaptosomal and Madin-Darby canine kidney (MDCK) cell membranes, leading to membrane permealization. Thus, the toxin may target the detergent-resistant membrane domains (DRMs) of these membranes, in analogy to aerolysin, a heptameric pore-forming toxin that associates with DRMs. To test this idea, we examined the distribution of radiolabeled epsilon-toxin in DRM and detergent-soluble membrane fractions of MDCK cells and rat synaptosomal membranes. When MDCK cells and synaptosomal membranes were incubated with the toxin and then fractionated by cold Triton X-100 extraction and flotation on sucrose gradients, the heptameric toxin was detected almost exclusively in DRMs. The results of a toxin overlay assay revealed that the toxin preferentially bound to and heptamerized in the isolated DRMs. Furthermore, cholesterol depletion by methyl-beta-cyclodextrin abrogated their association and lowered the cytotoxicity of the toxin toward MDCK cells. When epsilon-protoxin, an inactive precursor able to bind to but unable to heptamerize in the membrane, was incubated with MDCK cell membranes, it was detected mainly in their DRMs. These results suggest that the toxin is concentrated and induced to heptamerize on binding to a putative receptor located preferentially in DRMs, with all steps from initial binding through pore formation completed within the same DRMs.

Animals↗

PubMed2002

[A case of desmoplastic malignant mesothelioma with elevated serum CYFRA 21-1].

A 70-year-old woman was admitted to our hospital for medical evaluation of a right side pleural effusion, which was pointed out at another hospital. Chest CT revealed a right pleural effusion with diffuse and irregular pleural thickening. Percutaneous pleural biopsy showed hypocellular collagenous tissue without malignant cells. Though she received antituberculosis therapy, the pleural thickening progressed and the serum CYFRA 21-1 level was elevated. Chest pain and dyspnea appeared, and she was readmitted. However, pneumonia was present as a complication, and she died. At autopsy, the right pleura was thickened and invasion of the lung and the chest wall was observed. Microscopic findings showed increased amounts of hyalinized collagen fibers forming a storiform pattern. At the tumor foci, atypical cells with distinct nucleoli were observed. Desmoplastic malignant mesothelioma, which is rarely reported in Japan, was diagnosed.

Aged↗

PubMed2002

[An autopsy case of desmoplastic malignant mesothelioma].

On November 15, 2000, a 60-year-old man was admitted to our hospital with progressive dyspnea and right chest pain. He had a 40-year history of occupational asbestos exposure, which began when he was 20 years old. On admission, his chest radiographs showed pleural effusion on the right side, and asbestos bodies were detected in his sputum. Neither a cytological examination of the pleural effusion nor a histological examination of the pleura by percutaneous pleural biopsy revealed malignant cells. In addition, we could not find any other cause for the pleural effusion (such as tuberculosis, collagen disease, or heart failure). In May 2001, the patient also developed pleural thickening and pain in the right hypochondrium, and he was readmitted to our hospital on May 21, 2001. On readmission, an enhanced abdominal CT showed multiple liver tumors, and percutaneous pleural and liver biopsies were performed. The histological findings in the pleura and liver specimens revealed hypocellular collagen tissues without malignant cells. Thus, we could not determine the main cause either of the pleural effusion or of the patient's disease. However, his condition rapidly deteriorated, and he died on August 12, 2001. At the autopsy, bilateral pleural thickening, predominantly on the right side, and invasion of the lungs were observed. The histological findings in the pleural and hepatic tissues revealed hypocellular collagen fibers with a striate pattern and areas of neoplastic spindle cells. He was diagnosed as having malignant desmoplastic mesothelioma with liver metastasis. Cases of malignant desmoplastic mesothelioma have rarely been reported in Japan.

Humans↗

PubMed2002

[An autopsy case of protein-losing enteropathy due to gastrointestinal amyloidosis, occurring in empyema].

On August 14, 2001, a 76-year-old woman with a history of rheumatoid arthritis was admitted to our hospital with fever, cough, dyspnea and diarrhea. On admission, her chest radiography showed pleural effusion on the right side, and thoracocentesis was used to diagnose empyema. The patient underwent pleural drainage and received antibiotics. Alpha-Streptococcus was detected in both aerobic and anaerobic cultures of the pleural effusion. After 2 weeks of therapy, her empyema had improved; but her diarrhea, which had started 1 week before admission, had worsened, and her hypoproteinemia had progressed. Examination of the fecal clearance of alpha-1-antitrypsin and biopsied rectal material revealed that the diarrhea was caused by protein-losing enteropathy due to gastrointestinal amyloidosis secondary to rheumatoid arthritis. The patient was treated with steroids, but developed an additional infectious disease and died on September 29, 2001. In this case, she suffered from various infectious diseases including empyema and fungus infections. It has been reported that protein-losing enteropathy accompanies abnormalities in the immune system, by the loss of immunoglobulins and lymphocytes from the gut. We therefore suspect that protein-losing enteropathy due to gastrointestinal amyloidosis caused this patient's empyema.

Aged↗

PubMed2002

[A case in which progressive emphysematous changes were seen on chest computed tomography associated with Pneumocystis carinii pneumonia in a patient with AIDS].

A 60-year-old man was admitted to our hospital complaining of progressive dyspnea. On admission, he had marked hypoxemia, and his chest radiography and computed tomography (CT) showed ground glass opacities and multiple emphysematous changes in both lung fields. On examining the patient's bronchoalveolar lavage fluid (BALF). Pneumocystis carinii pneumonia (PCP) was diagnosed. A serological test for human immunodeficiency virus (HIV)-1, 2 was positive, and acquired immunodeficiency syndrome (AIDS) was diagnosed. Since the chest CT performed a month before the patient's admission to our hospital revealed ground glass opacities in both lung fields we thought that he had already developed PCP at that time. In comparison with his previous CT, the chest CT on admission showed progressive ground glass opacities and emphysematous changes. Although PCP is known to display various findings on chest radiography and CT, emphysematous changes are rarely reported in Japan. In this case we were able to confirm these changes and observe its progression using chest CT.

Acquired Immunodeficiency Syndrome↗

PubMed2002

[A case of scurvy with alveolar hemorrhage].

A 53-yr-old man with a history of chronic renal failure was admitted to the hospital of Hyogo College of Medicine on March 24th, 1999, because of severe continuous hemoptysis. On February 14th, 1999, the patient had undergone a cadaveric kidney transplantation in the urology department of another hospital. He did not experience any immunological reactions due to tissue rejection. On admission, subcutaneous bleeding at the site of an injection received 1 month before was noticed on his left arm. Petecheae of the extremities and a conjunctival hemorrhage were also noted. However, coagulation and fibrinolysis tests were essentially normal. These findings indicated that the hemorrhages were due to vessel weakness. Scurvy was diagnosed since his serum vitamin C was extremely low (0.2 microgram/ml). The patient was given ascorbic acid (1 g/day), and his condition improved dramatically. Ten years ago, the patient had had renal failure, which had been treated with chronic maintenance dialysis and dietary restriction. It has been postulated that a diet lacking in vitamin C or the steroid treatment he received after kidney transplantation may have induced the scurvy.

Hemorrhage↗