Biomedical subjects

M Miyamoto

Publications and source records attributed to M Miyamoto.

At least 109 records · Page 6Linked to original sources

PubMed2000

Improved quality and yield of islets isolated from human pancreata using a two-step digestion method.

A new approach, involving a two-step digestion process and Los Angeles preservation solution #1 (LAP-1), a cold storage solution, was developed for isolation of high-quality islets from human pancreata for transplantation. This approach markedly improves the islet yield, purity and viability, and the isolation success rate. In this method, the pancreas was digested first in warm collagenase solution for up to 20 minutes. After decanting the enzyme solution, partially digested tissue was dissociated by gentle agitation in cold LAP-1 solution without additional collagenase. The digested tissues were stored in cold LAP-1 solution until islet purification on Euro-Ficoll. Forty-six islet isolations were performed consecutively by the new method (group 1). These results were compared to those obtained earlier with 46 consecutive isolations, using our previous method that had been used before development of the new method (group 2). Our old method was a modification of Ricordi's method involving only warm collagenase digestion and the storage of digested tissues in cold Hanks balanced salt solution. All pancreata were partial, containing the body and tail. There were no significant differences in both groups with regard to the donor age, cold ischemic time, harvesting conditions, and pancreatic weight. Pancreas digestion was completed in approximately 1 hour in both groups. The isolation success rate as determined by viable islets after 2 days in culture was 93.5% (43 of 46 cases) in group 1, and 56.5% (26 of the 46) in group 2. Immediately after isolation, the new method yielded a total of 335,739 +/- 36,244 islets equivalent to 150 microm (IEQ) and 6,233 +/- 681 IEQ/g of pancreas with 83 +/- 2.5% purity, whereas the old method yielded a total of 195,587 +/- 25,242 IEQ and 3,763 +/- 5,509 IEQ/g with 69.2 +/- 4.7% purity. Isolated islets in group 1 maintained a good three-dimensional structure, displayed normal insulin release to high glucose stimulation in vitro, and restored euglycemia after transplantation into streptozotocin-diabetic athymic mice. The two-step digestion method provides a sufficient number of islets for transplantation from a single pancreas.

Adolescent↗

PubMed2000

Structural characterization of a new variant of the CYP2A6 gene (CYP2A61B) apparently diagnosed as heterozygotes of CYP2A61A and CYP2A6*4C.

During the course of investigating the frequency of a CYP2A6 whole deletion-type polymorphism (CYP2A6*4C) in Japanese, an unexpectedly large population of heterozygotes for CYP2A6*4C and the wild-type (CYP2A6*1A) was found. Cloning of a cDNA encoding CYP2A6 from the liver of individuals judged as heterozygotes for CYP2A6*4C and the CYP2A6*1A was carried out to identify the causal allele(s) responsible for a possible overestimation. A clone isolated from the liver cDNA library possessed 58 bp sequences in the 3'-untranslated region, which was replaced with the corresponding region of the CYP2A7 gene. The same gene conversion existed in the genomic DNA, indicating that the replacement was not a cloning artifact. Based on the gene structure of the allele (CYP2A6*1B), this variant was thought to be one of the causal alleles responsible for overestimation of heterozygotes for CYP2A6*4C and CYP2A6* A. To investigate this further, we developed a genotyping method which could distinguish the CYP2A6*A, CYP2A6*1B and CYP2A6*4C alleles from each other. The results clearly showed that CYP2A6*1B was the sole allele responsible for the overestimation. We conclude that the new genotyping method allows determination of six genotypes of the CYP2A6 gene, simultaneously and precisely, in both Oriental and Caucasian populations.

3' Untranslated Regions↗

PubMed2000

Epitope mapping of heat shock protein 60 (GroEL) from Porphyromonas gingivalis.

Porphyromonas gingivalis, a putative pathogen in human periodontal disease, possesses a 60-kDa heat shock protein (hsp60, GroEL). The GroEL homologs are known to be key molecules in auto-immune reactions because of the sequence similarity with human hsp60. In this study, B-cell epitopes on P. gingivalis GroEL (PgGroEL) were analyzed by both Western immunoblotting with truncated PgGroEL and by the multi-pin synthetic peptide approach. To examine auto-antibody production in periodontitis patients, Western immunoblotting with human gingival fibroblasts was performed. Deletion mutants were constructed from the cloned PgGroEL gene (P. gingivalis groEL), and four C-terminal truncated PgGroEL and one N-terminal truncated PgGroEL were prepared from the deletants. Sera from periodontitis patients reacted with all truncated PgGroEL used in this study. The results suggest that the B-cell epitopes were overlaid throughout PgGroEL. To determine the detailed locations of the B-cell epitope, 84 decapeptides covering the entire PgGroEL were synthesized and the serum IgG response to the peptides was examined. Epitope mapping using the synthetic peptides confirmed that the B-cell epitopes were overlaid throughout the length of PgGroEL and revealed that highly conserved peptides between PgGroEL and human hsp60 were recognized by the serum antibodies. Immuno-reactivity against human gingival fibroblasts was examined with sera from 30 periodontitis patients and 10 periodontally healthy subjects. IgG antibody against the 65-kDa antigen in human gingival fibroblasts (same molecular mass as human hsp60) was detected in two patients. Although IgG production against human hsp60 may be rare case in periodontitis patients, the results of epitope mapping demonstrated the potential of PgGroEL to cause the cross-reactions with human hsp60.

Amino Acid Sequence↗

PubMed2000

Decreased matrix metalloproteinase activity in the kidneys of hereditary nephrotic mice (ICGN strain).

Abnormalities of extracellular matrix (ECM) metabolism, i.e., overproduction and/or inhibition of ECM breakdown, may contribute to progression of fibrotic degeneration in the kidney. Earlier studies revealed that major ECM components, type I, III, and IV collagens, etc., were accumulated in glomeruli and tubulointerstitium in kidneys of Institute of Cancer Research (ICR) derived glomerulonephritis (ICGN) mice which are a novel inbred strain of mice with a hereditary nephrotic syndrome of unknown etiology and are considered to be a good model of human idiopathic nephrotic syndrome. In the present study, we compared the activities of matrix metalloproteinases (MMPs), a family of enzymes that degrade ECM components, in the kidneys of aged ICGN mice and age-matched ICR mice as normal controls. We biochemically measured interstitial collagenase (MMP-1), gelatinase (MMP-2 and MMP-9), and stromelysin (MMP-3) activities in the kidney tissues. Lower activities of MMP-1 and MMP-2 and MMP-9 were demonstrated in the kidneys of ICGN mice as compared with those of ICR mice, but there were no significant differences in the MMP-3 activities between these strains. These results show that decreased MMP activities cause abnormal accumulation of ECM in ICGN mouse kidneys.

Aging↗

PubMed2000

An epidemiologic study of occupational low back pain in truck drivers.

The factors in volved in occupational low back pain occurring in professional drivers were investigated epidemiologically with questionnaires (92 items) including low back symptoms, personal factors and occupational factors. The responses of one hundred fifty-three of one hundred eighty-one truck drivers who work in a large chemical industry corporation were analyzed after they had completely filled in questionnaires. As analysis of the results shows, the prevalence of LBP in one month of the survey was 50.3%. Correlating among data of personal factors and LBP, the prevalence of LBP was significantly higher in the drivers (Odd's ratio of 2.7) who answered "yes" to the item "shortage of spending time with family than in the drivers who didnt answer "yes. The occupational factors, working load and working environment showed no correlation with the prevalence of LBP. In contrast, 3 items of the working format related significantly to the prevalence of LBP: "irregular duty time (Odd's ratio of 3.0), "short resting time (2.4), and "long driving time in a day (2.0). Eighty-one of the 153 drivers (52.9%) pointed out the relationship between LBP and work, especially work which muolves vibration or road shock. Our results and the results from previous published studies suggested that vibration is an obvious risk factor for LBP. From the viewpoint of prophylaxis, an improvement in working conditions reduces the incidence of drivers' LBP to some extent.

Adult↗

PubMed2000

A case report of synovitis, acne, pustulosis, hyperostosis and osteitis syndrome presenting with spondylodiscitis.

SAPHO syndrome stands for synovitis, acne, pustulosis, hyperostosis and osteitis. The common site of skeletal lesions in this syndrome is the sternocostoclavicular area. Spondylodiscitis is rarely described in published studies. In general, skin lesions develop before the onset of skeletal lesions. We report a case of SAPHO syndrome in which spondylodiscitis developed more than 1 year before the onset of pustulosis.

Acne Vulgaris↗

PubMed2000

Characteristic changes in carbohydrate profile in the kidneys of hereditary nephrotic mice (ICGN strain).

The ICR-derived glomerulonephritis (ICGN) mice consist of heterozygous and homozygous groups and are considered to be a good model for human idiopathic nephrotic syndrome. To reveal changes in cell-surface carbohydrate construction, 24 lectins were applied to kidney sections of 10-, 30- and 50-week-old male heterozygous and homozygous ICGN mice and age-matched male ICR mice. Bandeiraea simplicifolia lectin-I (BSL-I), which specifically binds to alpha-D-galactopyranosyl groups, showed positive staining in the glomeruli of ICGN mice, but not in those of ICR mice. Positive BSL-I staining was observed only in distal tubules of homozygous ICGN mice. Lectin blotting for BSL-I demonstrated characteristic glycoproteins (45, 58 and 64 kD) in ICGN but not in ICR mice, and the levels of these molecules augmented in homozygous ICGN mice with the progression of renal failure. Moreover, succinylated wheat germ agglutinin, Dolichos biflorus agglutinin, Aleuria aurantia lectin and Ulex europaeus agglutinin-I showed positive staining only in the glomeruli of homozygous ICGN mice, but not in those of heterozygous ICGN or ICR mice. The staining intensities of Ricinus communis agglutinin-I, Phaseolus vulgaris agglutinin-E and -L, Lens culinaris agglutinin and Erythrina cristagalli agglutinin (ECL) in the glomeruli of homozygous ICGN mice were stronger than those of heterozygous ICGN and ICR mice. In conclusion, lectin histochemistry provided useful information for the diagnosis and prognosis of nephrotic lesions. Characteristic BSL-I binding glycoproteins may be pathogenic factors which cause renal disease in ICGN mice and are good tools to investigate the molecular mechanism of renal disorders in ICGN mice.

Animals↗

PubMed2000

Hepatitis-associated aplastic anemia and transfusion-transmitted virus infection.

A 17-year-old man was admitted to our hospital because of severe acute hepatitis. Serologic studies were negative for A, B, C and G hepatitis viruses. Later, he was found to be positive for transfusion-transmitted virus (TTV) DNA. He was discharged after normalization of liver function tests. Four months after the onset of hepatitis, he was re-admitted because of pancytopenia. Bone marrow findings were consistent with aplastic anemia. The anemia responded to steroid therapy. In this case, TTV was probably involved in the development of aplastic anemia.

Acute Disease↗

PubMed2000

Crescentic glomerulonephritis with positive antineutrophil cytoplasmic autoantibody specific for myeloperoxidase associated with autoimmune hemolytic anemia and thrombocytopenic purpura.

A 41-year-old woman was admitted to the hospital with severe uremia, hemolytic anemia, and thrombocytopenic purpura. Emergency hemodialysis with plasmapheresis was started in view of consideration of hemolytic uremic syndrome (HUS), which resulted in improvement of renal function and platelet count. Positive antineutrophil cytoplasmic autoantibody specific for myeloperoxidase (MPO-ANCA) suggested crescentic glomerulonephritis, which was pathologically evidenced by renal biopsy. The diagnosis of MPO-ANCA associated crescentic glomerulonephritis with autoimmune hemolytic anemia (AIHA) and thrombocytopenic purpura were confirmed. Three courses of steroid pulse therapy with heparin were successfully performed, followed by oral prednisolone and warfarin. Such a case has not been previously reported to our knowledge.

Adult↗

PubMed2000

Central selective acetylcholinesterase inhibitor with neurotrophic activity: structure-activity relationships of TAK-147 and related compounds.

A series of benzylamino inhibitors of acetylcholinesterase (AChE) have been designed based on a working hypothesis of the enzyme s active site. These compounds were tested for their inhibitory activities on AChE and potent inhibitors were further evaluated in terms of central selectivity. These studies led to a discovery of 3-[1-(phenylmethyl)-4-piperidinyl]-1-(2,3,4, 5-tetrahydro-1H-1-benzazepin-8-yl)-1-propanone fumarate (TAK-147). Pharmacokinetic study has shown that the compound has high central selectivity, as demonstrated by rapid elimination from plasma and long-term existence in the brain. As a consequence, TAK-147 ameliorates impairments of learning and memory in various animal models without producing peripheral side effects. TAK-147 also activates the monoaminergic systems and energy metabolism. Furthermore, TAK-147 was revealed to have NGF-like neurotrophic activity on central cholinergic neurons at concentrations where it inhibits AChE activity. Therefore, TAK-147 is expected not only to ameliorate the clinical symptoms in Alzheimer s disease via AChE inhibition but to prevent or slow the progression of the disease via its neurotrophic action. TAK-147 is now under clinical trial as a therapeutic drug for Alzheimer s disease. This article reviews design and structure-activity relationships of TAK-147 and related compounds. Preclinical pharmacology of TAK-147 is also summarized.

Alzheimer Disease↗

PubMed2000

Acute cardiovascular effects and pharmacokinetics of carvedilol in healthy dogs.

OBJECTIVE: To determine acute cardiovascular effects and pharmacokinetics of carvedilol in healthy dogs. ANIMALS: 14 mature healthy Beagles. PROCEDURE: 12 dogs were anesthetized with morphine and alpha-chloralose. Catheters were placed in the aorta, left ventricle, and right atrium to record systemic and pulmonary pressures and determine vascular resistance and cardiac output. Electrocardiograms (leads I, aVF, and V3) were recorded to determine electrocardiographic changes. Variables were measured before and after IV injection of incremental doses of carvedilol (cumulative doses, 10, 30, 70, 150, 310, and 630 microg/kg of body weight; n = 6) or vehicle alone (6). Pharmacokinetic analysis was performed, using 2 conscious dogs given 160 microg of carvedilol/kg as a single IV injection. RESULTS: Heart rate and velocity of fiber shortening at zero load (Vmax) increased slightly but significantly from baseline values at doses of carvedilol > or = 310 microg/kg and 10 microg/kg, respectively. Carvedilol did not affect systemic and pulmonary pressures or vascular resistances. Intravenous administration of approximately 150 microg of carvedilol/kg resulted in a plasma carvedilol concentration of approximately 100 ng/ml. Mean elimination half-life was 54 minutes, half-life of distribution was 3.5 minutes, and volume of distribution was 2,038 ml/kg. CONCLUSIONS AND CLINICAL RELEVANCE: The therapeutic plasma concentration of carvedilol in humans is 100 ng/ml. At that plasma concentration in dogs, the reduction in afterload and positive inotropic effect that we observed would be beneficial for treating heart failure and minimizing the cardiotoxic effects of doxorubicin.

Adrenergic alpha-Antagonists↗

PubMed2000

[Emotion recognition: facial components associated with various emotions].

This study examined the effect of the changes in facial expressions in different parts of the face on emotion recognition. Fifty-two university students participated in the study. Seven emotions were selected as being the most suitable for categorization and expression: namely, anger, fear, surprise, disgust, sadness, happiness, and neutrality. Picture of these emotions were used to create stimulus materials, composed facial expressions were created by combining the upper and the lower parts of the pictures expressing different emotions. The participants were asked to categorize the type of emotion represented by each picture. The results showed that the upper area of the face was more often associated with anger, fear, surprise, and sadness. On the contrary, the lower area was more often associated with disgust and happiness. There were no significant differences between parts of the face associated with neutral emotions. Based on these results, we conclude that affected areas of the face differed as a function of emotion being experienced. Finally, the relationship of our results with Yamada's model (1993) was discussed.

Adult↗

PubMed2000

Disinfectant effects of hot water, ultraviolet light, silver ions and chlorine on strains of Legionella and nontuberculous mycobacteria.

The disinfectant effects on Legionella and nontuberculous mycobacteria of hot water, ultraviolet light, silver ions and chlorine, were evaluated. The bacterial strains Legionella pneumophila ATCC33152 and Mycobacterium avium ATCC25291 and strains of L. pneumophila and M. avium which had been isolated from a 24 h bath, were examined for their resistance to treatments. All strains were killed within 3 min on exposure to hot water at 70 degrees C and exposure to ultraviolet light at 90 mW.s/cm2. The strains of L. pneumophila tested were killed within 6 h on exposure to a solution of silver ions at 50 micrograms/l. The number of viable cells of strains of M. avium fell from 10(5) CFU/ml to 10(3) CFU/ml after exposure to an aqueous solution of silver ions at 100 micrograms/l for 24 h. Chlorine effectively killed strains of Legionella which were exposed to an aqueous solution of chlorine at 2 mg/l within 3 min, but strains of Mycobacterium survived exposure to chlorine at 4 mg/l for more than 60 min.

Chlorine↗

PubMed2000

[A case of multiple sclerosis with hypothalamic amenorrhea].

We present a 31-year-old woman of multiple sclerosis. At age 28, she was admitted with complaints of echolalia and a gradual onset of weakness affecting the right upper and bilateral lower limbs. Brain MRI showed high intensity areas in the bilateral frontal gyri, lobuli paracentralis, and left anterior thalamus. Although she had been in remission for 3 years, she developed dysesthesia of left upper and lower limbs. Cervical T2 weighted MRI showed a new high signal intensity lesion in the spinal cord from the C2 to C3 level. The combination of the cerebral, thalamic and spinal cord lesions with remission and excerbations allowed the diagnosis of clinically MS to be made. She suffered amenorrhea from the onset of her illness. Serum prolactin was within the normal range. The LH and FSH basal secretions were decreased and there were low delayed secretions of LH and FSH after intravenous injection of 100 micrograms LHRH. We consider that her amenorrhea was caused by the hypothalamic lesion, supported by MR findings of dilatation of the third ventricle.

Adult↗

PubMed2000