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Biomedical subjects

J Miyamoto

Publications and source records attributed to J Miyamoto.

At least 19 recordsLinked to original sources
PubMed2001

Suppression of high-pressure-induced hemolysis of human erythrocytes by preincubation at 49 degrees C.

When human erythrocytes were preincubated at 37-52 degrees C under atmospheric pressure before exposure to a pressure of 200 MPa at 37 degrees C, the value of hemolysis was constant (about 43%) up to 45 degrees C but became minimal at 49 degrees C. The results from anti-spectrin antibody-entrapped red ghosts, spectrin-free vesicles, and N-(1-pyrenyl)iodoacetamide-labeled ghosts suggest that the denaturation of spectrin is associated with such behavior of hemolysis at 49 degrees C. The vesicles released at 200 MPa by 49 degrees C-preincubated erythrocytes were smaller than those released by the treatment at 49 degrees C or 200 MPa alone. The size of vesicles released at 200 MPa was independent of preincubation temperature up to 45 degrees C, and the vesicles released from 49 degrees C-preincubated erythrocytes became smaller with increasing pressure up to 200 MPa. Thus, hemolysis and vesiculation under high pressure are greatly affected by the conformation of spectrin before compression. Since spectrin remains intact up to 45 degrees C, the compression of erythrocytes at 200 MPa induces structural changes of spectrin followed by the release of large vesicles and hemolysis. On the other hand, in erythrocytes that are undergoing vesiculation due to spectrin denaturation at 49 degrees C, compression produces smaller vesicles, so that the hemolysis is suppressed.

Air Pressure↗
PubMed2001

Development of growth hormone and adrenocorticotropic hormone deficiencies in patients with prenatal or perinatal-onset hypothalamic hypopituitarism having invisible or thin pituitary stalk on magnetic resonance imaging.

A gradual loss of anterior pituitary hormones is suspected in patients treated with irradiation due to brain tumors. Development of growth hormone deficiency (GHD) with age has been documented in patients with idiopathic GHD. A gradual loss of adrenocorticotropic hormone (ACTH) secretion has been also shown in a patient with severe GHD and an invisible pituitary stalk on magnetic resonance imaging (MRI). The purpose of this longitudinal and cross-sectional study was to evaluate the gradual loss of growth hormone (GH) and ACTH in a homogeneous group of patients with hypopituitarism. Twenty-eight patients (23 males, 5 females) from four hospitals were diagnosed as having prenatal or perinatal-onset hypothalamic hypopituitarism. They had an abnormal pituitary stalk on MRI (invisible in 18 patients, thin in 10 patients) without any other organic disease of the brain. Each patient had GHD upon initial evaluation. Height (n=20) was analyzed as standard deviation score (SDS). Longitudinal (n=8) and cross-sectional (n=28) GH secretion capacity was evaluated by GH peaks, in response to insulin tolerance test (ITT) and growth hormone releasing factor test (GRF test). Longitudinal (n=10) and cross-sectional (n=28) ACTH secretion capacity was evaluated by cortisol peaks in response to ITT. Height SDS decreased each year in all the untreated patients after birth. GH peaks decreased gradually with age. Longitudinal data showed decreased GH peaks with age in seven out of eight patients using ITT and in all four patients using GRF tests. Cortisol peaks also decreased gradually together with signs and symptoms for adrenal deficiency such as general fatigue. Cortisol peaks of less than 414 nmol/L (15 microg/dl) in response to ITT were seen in 24% of the tests before age 10 and 56% before age 25. In conclusion, GHD and ACTH deficiency developed gradually in patients with prenatal or perinatal-onset hypothalamic hypopituitarism who had invisible or thin pituitary stalks examined by MRI.

Adolescent↗
PubMed2000

Pretreatment with diazepam suppresses the reduction in defensive freezing behavior induced by fluvoxamine in the conditioned fear stress paradigm in mice.

The effects of the selective serotonin (5-hydroxytryptamine (5-HT)) reuptake inhibitor fluvoxamine, given alone or in combination with the benzodiazepine anxiolytic diazepam on the defensive freezing behavior of mice in the conditioned fear stress paradigm were examined. Fluvoxamine (5-20 mg/kg, i.p.) induced a dose-dependent reduction in freezing behavior. In contrast, while low doses of diazepam (0.125 and 0.25 mg/kg, i.p.) reduced the freezing behavior, such effects were not observed with high doses of diazepam (0.5 and 1 mg/kg, i.p.). In the combination study, fluvoxamine (20 mg/kg, i.p. ) did not reduce the freezing behavior in mice that had been pretreated with diazepam (0.125-1 mg/kg, i.p.). None of the doses of fluvoxamine and diazepam used in the present study had any effects on motor activity under non-stressed conditions. These results suggest that benzodiazepines may negatively influence the clinical efficacy of selective 5-HT reuptake inhibitors in the treatment of anxiety disorders.

Animals↗
PubMed2000

Assessment of drug concentrations in tears in therapeutic drug monitoring: I. Determination of valproic acid in tears by gas chromatography/mass spectrometry with EC/NCI mode.

A rapid and sensitive method for the quantitation of valproic acid in tears has been developed using gas chromatography/electron capture negative chemical ionization/mass spectrometry. Valproic acid was converted directly into its pentafluorobenzyl ester derivative without the need to perform any extraction from the biologic fluid. The concentrations in tears [C]t correlated very well with those of the free form in the plasma [Cf]p and those of the total form in the plasma [Cb+f]p. The ratios between valproic acid concentrations in tears and plasma were as follows: [C]t/[Cb+f]p = 0.10 +/- 0.02; [C]t/[Cf]p = 0.57 +/- 0.11. Ratios of [C]t/[Cb+f]p were in good agreement with previously published data.

Anticonvulsants↗
PubMed2000

Bile acids in porcine fetal bile.

A study of the biliary bile acid composition in porcine fetus compared with that of the adult pig is described. Biles, collected during gestation (weeks 4, 15 to 17 and at birth), aged six months and two years old, were analyzed by gas-liquid chromatography and capillary GC-MS. Bile acids were separated into different conjugate groups by chromatography on the lipophilic anion exchange gel, piperidinohydroxypropyl Sephadex LH-20. All and one fourth of the total bile acids in the bile of weeks 4 and 15 of gestation, respectively, were present as unconjugated form, however, only a trace of unconjugated bile acids was present in bile of late gestation, the young and the adult pigs. The ratio of glycine/taurine (G/T) conjugates in the conjugated fraction of the fetal bile at 15 weeks gestation was less than 1, which markedly contrasted with the conjugation pattern for adult bile where the ratio of G/T conjugates was approximately more than 9. The predominant acids identified in porcine fetal bile of the 4 weeks gestation were cholic acid (3alpha,7alpha,12alpha-trihydroxy-5beta-chola n-24-oic acid) and chenodeoxycholic acid (3alpha,7alpha -dihydroxy-5beta-cholan-24-oic acid). However, cholic acid in late gestation, young, and adult bile was the smallest component, whereas chenodeoxycholic acid was still the major constituent of these biles. The presence of small but valuable amounts of allocholic acid (3alpha,7alpha,12alpha-trihydroxy-5alpha-chol an-24-oic acid) and cholic acid in early gestation suggested the presence of 12alpha-hydroxylase activity of steroid nucleus in fetal liver. Considerable amounts of glycine-conjugated hyodeoxycholic acid were found in the bile of the gestation periods, suggesting the placental transfer of this bile acid from maternal circulation.

Aging↗
PubMed2000

Molecular cloning of the gene encoding an outer-membrane-associated beta-N-acetylglucosaminidase involved in chitin degradation system of Alteromonas sp. strain O-7.

The gene encoding beta-N-acetylglucosaminidase (GlcNAcaseA) was cloned using PCR with degenerate oligonucleotide primers from the partial amino acid sequence of the enzyme. The gene encoded a polypeptide of 863 amino acids with a predicted molecular mass of 97kDa. A characteristic signal peptide, which was present at the amino-terminus of the precursor protein, contained four amino acids (Ala-Gly-Cys-Ser) identical in sequence and location to the processing and modification sites of the outer membrane lipoprotein of Escherichia coli, indicating that the mature GlcNAcaseA is a lipoprotein the N-terminal cysteine residue of which would be modified by the fatty acid that anchors the protein in the membrane. The predicted amino acid sequence of GlcNAcaseA showed similarity to bacterial beta-N-acetylglucosaminidases belonging to the family 20 glycosyl hydrolases.

Acetylglucosaminidase↗
PubMed2000

Final height of Japanese patients with X-linked hypophosphatemic rickets: effect of vitamin D and phosphate therapy.

X-linked hypophosphatemic rickets (XLH) is one of the most common causes of rickets in infancy and childhood. Combination therapy of vitamin D and phosphate is generally used for patients with XLH. Effect of treatment of vitamin D and phosphate during childhood on final height of XLH has to be elucidated in Japanese. There have been only three Caucasian studies on final height of XLH with treatment since childhood. Purpose of this study is to report adult height and therapeutic effect of 22 Japanese participants (5 males, 17 females) with XLH who were treated with phosphate (33-200 mg/kg/day as phosphorus divided into 3 or 4 doses) and vitamin D (vitamin D2 or 1alpha-hydroxyvitamin D3) for more than five years and evaluate effect of the treatment on the final height retrospectively. Final height (FHt) for all participants was -1.69+/-11.11 SD. FHt (-1.69+/-1.11 SD) was significantly higher than height at the initiation of treatment (-2.38+/-0.88 SD) for all participants (P<0.01). In conclusion, combination therapy of vitamin D and phosphate improved final height of Japanese patients with XLH as is similar to previous Caucasian studies.

Adult↗
PubMed2000

Type 1 diabetes mellitus caused by treatment with interferon-beta.

A 57-year-old man was referred to our outpatient clinic after interferon-beta (IFN-beta) treatment for 7 weeks. While IFN-beta therapy was continued in our outpatient clinic, his blood glucose level increased gradually, and he was admitted to our hospital for hyperglycemia. The patient was prescribed a 1,600-kcal diet and intensive insulin therapy was performed. GAD antibody became positive 15 months after the start of IFN therapy, and disappeared 27 months after the start of IFN therapy. Insulin secretion was depleted and the patient had HLA-DR4, B54, and DRB1*0405. This appears to be a case of type 1 diabetes mellitus induced by administration of IFN-beta alone.

Antiviral Agents↗
PubMed2000

[Two cases of multiple primary cancer involving the lung with old pulmonary tuberculosis].

We reported 2 relatively rare cases of multiple primary cancer including lung cancer accompanied by old pulmonary tuberculosis. Patient 1 was a 62-year-old man admitted to our hospital for further evaluation of an infiltrative shadow on chest X-ray films, and a cervical tumor noted 10 years earlier and thought to be thyroid cancer. A Transbronchial lung biopsy (TBLB) specimen disclosed poorly differentiated squamous cell carcinoma. A right upper lobectomy and thyroidectomy were performed. Histopathologic findings showed a neoplastic lesion adjacent to caseous necrosis with formation of granuloma consistent with tuberculosis. Also, the cervical tumor was considered to be a metastatic lymph node from thyroid papillary carcinoma. Patient 2 was a 73-year-old man with a 14-year history of treatment for transitional cell carcinoma of urinary bladder, who had been admitted to our hospital for further evaluation because of a nodular shadow observed on chest X-ray films. TBLB specimens disclosed adenocarcinoma. A right upper lobectomy was performed. Histopathologic findings revealed a neoplastic tumorlet in the same lobe. No detectable increases in serum TNF-alpha, IL-1 beta or IFN-gamma were observed in either patient. Phytohemagglutinin- and concanavalin-A-stimulated lymphocyte proliferation decreased in Patient 1. These findings suggested that the immunocompromised status of patients with cancer in addition to old pulmonary tuberculosis may contribute to the development of lung cancer.

Adenocarcinoma↗
PubMed2000

Patient access to medical records: problems and strategies for inpatient charts.

Fasing the impending introduction of patient access to medical charts, we have attempted to include a more substantial description of medical activity in specific areas. Using the guidelines published jointly by the Ministry of Health and Welfare and the Tokyo Metropolitan Office in October 1998, the staff of the medical records division examined and evaluated the layout and description of items on individual hospital charts, with excellent results. To encourage the continued improvement of medical chart recording in the future, incentives should be implemented to avoid insufficient descriptions, encourage regular chart inspections, and promote education regarding the need for a systematic approach to charts and chart recording.

Forms and Records Control↗
PubMed1999

Enhancing effects of salicylate on tonic and phasic block of Na+ channels by class 1 antiarrhythmic agents in the ventricular myocytes and the guinea pig papillary muscle.

OBJECTIVE: To study the interaction between salicylate and class 1 antiarrhythmic agents. METHODS: The effects of salicylate on class 1 antiarrhythmic agent-induced tonic and phasic block of the Na+ current (INa) of ventricular myocytes and the upstroke velocity of the action potential (Vmax) of papillary muscles were examined by both the patch clamp technique and conventional microelectrode techniques. RESULTS: Salicylate enhanced quinidine-induced tonic and phasic block of INa at a holding potential of -100 mV but not at a holding potential of -140 mV; this enhancement was accompanied by a shift of the hinfinity curve in the presence of quinidine in a further hyperpolarized direction, although salicylate alone did not affect INa. Salicylate enhanced the tonic and phasic block of Vmax induced by quinidine, aprindine and disopyramide but had little effect on that induced by procainamide or mexiletine; the enhancing effects were related to the liposolubility of the drugs. CONCLUSIONS: Salicylate enhanced tonic and phasic block of Na+ channels induced by class 1 highly liposoluble antiarrhythmic agents. Based on the modulated receptor hypothesis, it is probable that this enhancement was mediated by an increase in the affinity of Na+ channel blockers with high lipid solubility to the inactivated state channels.

Action Potentials↗
PubMed1999

Are Actions Regretted More Than Inactions?

Several researchers have claimed that negative outcomes produce greater regret when they result from actions rather than from failures to act (Gleicher et al., 1990; Kahneman & Tversky, 1982; Landman, 1987). We investigated this claim by asking participants to write descriptions of strongly regretted events in their own lives and to rate the intensity of the regrets. Participants reported more inaction than action regrets, and, contrary to prior research findings, regrets produced by actions and inactions were equally intense. We conjecture that many factors that affect the content of real-life regrets are eliminated in studies of hypothetical regret. In real life, actions and inactions do not generally produce the same outcomes. Furthermore, actions and inactions may differ in how easily one can anticipate the potential for harm. Specifically, it is plausible that people control their actions to avoid potential regrets, leaving themselves vulnerable to regrets from inactions. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

A case of congenital hypopituitarism: difficulty in the diagnosis of ACTH deficiency due to high serum cortisol levels from a hypothyroid state.

A three-month-old boy presented congenital hypopituitarism in which the hypothyroid state masked ACTH deficiency. Multiple anterior pituitary hormone deficiencies, including ACTH, were finally confirmed. High basal serum cortisol levels (up to 45.1 microg/dl) were observed during a stressful episode before L-thyroxine replacement therapy was started. Decreased morning serum cortisol levels (5.0 microg/dl or below) were observed on the sixth day of L-thyroxine replacement therapy despite mild hypoglycemia (lowest serum glucose level of 50 mg/dl). ACTH deficiency was then confirmed by insulin-induced hypoglycemia test (peak serum cortisol level of 4.9 microg/dl). The present findings showed that serum cortisol levels can be high during a stressful episode in an infant with ACTH deficiency and a coexisting hypothyroid state. Thus, the diagnostic evaluation of adrenal function soon after L-thyroxine replacement therapy is important in order to verify a possible subclinical ACTH deficiency, even in the presence of high serum cortisol levels before L-thyroxine replacement therapy.

Adrenocorticotropic Hormone↗
PubMed1999

[The clinical evaluation of MTD false-positive & false-negative results].

The usefulness of MTD (Amplified Mycobacterium Tuberculosis Direct Test) for a rapid diagnosis of tuberculosis was evaluated. A total of 400 clinical samples obtained from July, 1995 to June, 1997 were tested by MTD, direct microscopy and culture. The results of MTD and smear/culture were coincident in 387 out of 400 samples. Eight samples (2%) were MTD false-positive (i.e. they were MTD positive but smear and culture negative), and 5 (1.25%) were MTD false-negative (i.e. MTD negative but smear and/or culture positive). Despite a careful review of the clinical data of those patients whose samples showed discrepant results, the reasons of discrepancy were not clear in 2 (0.5%) of the 8 false positives and 3 (0.75%) of the 5 false negatives. In the other cases, the MTD false positives may be accounted for the presence of previous M. tuberculosis infection, the influence of anti-tuberculous medication and so on, and the MTD false negatives are most likely due to the presence of inhibitors (blood, for example) or to the small number of organisms in the specimens. It can be concluded that adequate samples should be obtained, and that MTD should be repeated in case of discrepant results.

Adult↗
PubMed1998

[A case of human infection with Clinostomum sp].

The genus Clinostomum is a cause of parasitic laryngo-pharyngitis. We report the 15th case of Clinostomum sp. infection in Japan. A 29-year-old female visited our hospital because of throat discomfort and expectoration of a worm by sneezing on November 17, 1997. The pharyngitis was caused by the worm. The worm was morphologically identified as the adult of the genus Clinostomum.

Adult↗
PubMed1997

Simultaneous determination of plasma mevalonate and 7alpha-hydroxy-4-cholesten-3-one levels in hyperlipoproteinemia: convenient indices for estimating hepatic defects of cholesterol and bile acid syntheses and biliary cholesterol supersaturation.

The high prevalence of cholesterol gallstone disease in hypertriglyceridemic patients may be associated with frequent metabolic defects in cholesterol and bile acid syntheses and in the concomitant formation of bile supersaturated with cholesterol. This study had the two aims: 1) to assess whether the defects as well as the degree of biliary cholesterol supersaturation in patients with hyperlipoproteinemia (HLP) can be estimated by the simultaneous determination of plasma mevalonate (MVL) and 7alpha-hydroxy-4-cholesten-3-one (C4); and 2) to assess the possible application of an estimated cholesterol saturation index ([CSI]E) as a means of evaluating the clinical effects of simvastatin on biliary lipid composition. Biliary cholesterol supersaturation was observed in patients with both IIa and IV HLP types. Consistent with the high activity and steady-state messenger RNA level of 3-hydroxy-3 methylglutaryl coenzyme A (HMG-CoA) reductase, plasma MVL was significantly higher in 86 patients with HLP (38 type IIa, 44.1 +/- 2.4 nmol/L and 48 type IV, 56.7 +/- 2.3; P < .01) than in 41 normolipidemic subjects (34.2 +/- 1.5), closely correlating with the molar percentage of cholesterol in bile (r = .61, P = .0001; n = 86). On the other hand, consistent with the high activity and messenger RNA level of cholesterol 7alpha-hydroxylase, plasma C4 was significantly higher in patients with HLP (type IIa, 28.8 +/- 2.3 nmol/L and type IV, 38.3 +/- 2.7; P < .01) than in normolipidemic subjects (17.4 +/- 1.5). Plasma C4 was closely correlated with plasma MVL (r = .40, P = .0001; n = 86), but was inversely correlated with the molar percentage of bile acids in bile (r = .49, P = .0001; n = 86). Assuming that cholesterol supersaturation in patients with HLP may be governed by both an enhanced cholesterol secretion (closely reflected by plasma MVL) and a decreased secretion of bile acids (closely reflected by plasma C4), the multivariate linear regression-analyses revealed that an index defined as estimated CSI ([CSI]E) (%) in patients with HLP was given by the following equation using plasma MVL and C4 (nmol/L): [CSI]E = 1[MVL] + 0.7[C4] + 44.4. Biliary cholesterol supersaturation in patients treated with simvastatin improved in a manner parallel to the time course of decreases in plasma MVL and C4. The [CSI]E before and at the end of treatment were correlated with biliary CSI. These results indicate that defects of hepatic cholesterogenesis, and bile acid synthesis, and the degree of biliary cholesterol supersaturation in patients with HLP can be estimated exactly by the simultaneous determination of plasma MVL and C4; furthermore [CSI]E may be adopted for clinical use as a convenient index of biliary CSI.

Adult↗