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Biomedical subjects

J Takaya

Publications and source records attributed to J Takaya.

At least 19 recordsLinked to original sources
PubMed2006

Possible relationship between low birth weight and magnesium status: from the standpoint of "fetal origin" hypothesis.

Magnesium deficiency in pregnant women is frequently seen because of inadequate or low intake of magnesium. Magnesium deficiency during pregnancy can induce not only maternal and fetal nutritional problems, but also consequences that might last in offspring throughout life. Many epidemiological studies have shown that restricted fetal growth, i.e. intrauterine growth retardation (IUGR), is associated with an increased risk of insulin resistance in adult life. We previously postulated that the intracellular magnesium of cord blood platelets is lower in the small for gestational age group than in the appropriate for gestational age group, suggesting that intrauterine magnesium deficiency may result in IUGR. Taken together, intrauterine magnesium deficiency in the fetus may lead to or program the insulin resistance after birth. We hypothesize that intrauterine magnesium deficiency may induce a metabolic syndrome in later life. Prospective studies will further clarify whether infants with IUGR induced by magnesium deficiency are at higher risk for metabolic syndromes in childhood or adulthood.

Adult↗
PubMed2004

A case of Kawasaki disease associated with syndrome of inappropriate secretion of antidiuretic hormone.

UNLABELLED: Kawasaki disease (KD) is an acute vasculitis of unknown aetiology with varied clinical manifestations. Although coronary arteritis is common in the course of KD, central nervous system involvement is rare. We report a case of KD in an infant who developed convulsions and apnoea during his illness associated with syndrome of inappropriate secretion of antidiuretic hormone (SIADH). CONCLUSION: The possibility of severe hyponatraemia should be anticipated in children with KD. Infants with KD are at risk of SIADH and should be monitored closely for its development.

Humans↗
PubMed2001

In situ demonstration of angiotensin-dependent and independent pathways for hyperaldosteronism during chronic extracellular fluid volume depletion.

In wild-type mice, 2-wk administration of losartan, an angiotensin (Ang) II type 1 (AT1) receptor antagonist, along with dietary sodium restriction, resulted in an elevation of plasma aldosterone greater than that seen with sodium restriction alone (2.75 +/- 0.35 vs. 1.38 +/- 0.16 ng/ml, P < 0.01). Plasma potassium increased in sodium-restricted, losartan-treated mice (6.0 +/- 0.2 mEq/liter), while potassium remained unchanged in mice with sodium restriction alone. To study the effect of Ang II on glomerulosa cells that may operate independently of plasma potassium in situ, we used chimeric mice made of cells with or without the intact AT1A gene (Agtr1a). When animals were fed a normal diet or chronically infused with Ang II, the aldosterone synthase mRNA was detectable only in Agtr1a+/+ but not Agtr1a-/- zona glomerulosa cells. After 2 wk of sodium restriction, plasma aldosterone increased (1.51 +/- 0.27 ng/ml) and potassium remained on average at 4.5 +/- 0.2 mEq/liter, with aldosterone synthase mRNA expressed intensively in Agtr1a+/+, but not detectable in Agtr1a-/- cells. Simultaneous sodium restriction and losartan treatment caused increases in plasma potassium (5.5 +/- 0.1 mEq/liter) and aldosterone (1.84 +/- 0.38 ng/ml), with both Agtr1a-/- and Agtr1a+/+ cells intensively expressing aldosterone synthase mRNA. Thus, aldosterone production is regulated by Ang II in the adrenal gland during chronic alterations in extracellular fluid volume when plasma potassium is maintained within the normal range. In the light of a previous observation that dietary potassium restriction superimposed on sodium restriction abolished secondary hyperaldosteronism in angiotensinogen null-mutant mice, the present findings demonstrate that when the renin-Ang system is compromised, plasma potassium acts as an effective alternative mechanism for the volume homeostasis through its capacity to induce hyperaldosteronism.

Adrenal Glands↗
PubMed2001

Association of seropositivity for antibody to Chlamydia-specific lipopolysaccharide and coronary artery disease in Japanese men.

Recent studies suggest an association between Chlamydia pneumoniae infection and coronary artery disease (CAD). To examine this relationship in Japanese men, serum IgA and IgG antibodies to Chlamydia-specific lipopolysaccharide were measured by enzyme-linked immunosorbent assay in 507 patients with CAD and 200 age-matched controls. CAD patients were divided into (1) 269 patients with myocardial infarction (MI) and (2) 238 patients with chronic coronary heart disease (CCHD). Compared with the control group, the CAD group did not differ in the prevalences of both antibodies (IgA: 23.7 vs 18.0%, p=0.10; IgG: 52.7 vs 51.0%, p=0.6). The index of IgG antibody was not significantly different between CAD and control groups (median 1.19 vs 1.18, p=0.3), whereas the index of IgA antibody was significantly higher in CAD than control group (median 0.60 vs 0.46, p<0.0001). Compared with the control group, the MI group had a significantly higher prevalence of IgA antibody (28.6 vs 18.0%, p=0.007); however, there was no difference in the prevalence of IgG antibody (58.0 vs 51.0%, p=0.13). The CCHD group did not differ in the prevalences of both antibodies (IgA: 18.1 vs 18.0%, p=0.9; IgG: 45.6 vs 51.0%, p=0.2). After the adjustment for coronary risk factors, odds ratios (ORs) of seropositive antibodies for CAD were 1.59 [95% confidence interval (CI): 0.88-2.87, p=0.12] for IgA seropositivity and 0.92 (95%CI: 0.58-1.47, p=0.7) for IgG seropositivity in all cases. In the MI and control groups, ORs of seropositive antibodies for MI were 2.67 (95%CI: 1.32-5.38, p=0.007) for IgA seropositivity, and 1.36 (95%CI: 0.79-2.36, p=0.2) for IgG seropositivity. This study discovered that IgA antibody to Chlamydia was significantly associated with CAD, especially with MI, in Japanese Men and the findings suggest that chronic infection of Chlamydia may be linked to the pathogenesis of MI.

Aged↗
PubMed2000

Dual renin gene targeting by Cre-mediated interchromosomal recombination.

This study describes a new approach to targeting clustered genes. Our study began with the establishment of two lines of mice carrying different mutations in either Ren1 or Ren2. These two genes, both encoding renin, span over 40 kb in tandem on chromosome 1. Each gene was mutated by gene targeting to contain loxP sites. These two mutants and Cre transgenic mice were mated to produce offspring carrying the mutant Ren1 and Ren2 genes, as well as the Cre transgene concurrently. Initially, two mutant Ren genes were located on separate chromosomes. Southern analysis of mice from the second generation revealed that the mutant Ren1 and Ren2 were interchromosomally recombined at the loxP sites to produce a new dually mutated allele on the chromosome at the rate of 9.6% (7/73). Thus, interchromosomal recombination can be efficiently programmed by mating as designed using the Cre-loxP system.

Animals↗
PubMed2000

Can magnesium act as a second messenger? Current data on translocation induced by various biologically active substances.

Free intracellular Mg2+([Mg2+]i) can potentially integrate the signals from hormones, cellular metabolism and organismal ion homeostasis and affect the activities of ion channel and other effectors. Interest in [Mg2+]i has been heightened by recent reports that small changes in [Mg2+]i in the physiological range can significantly modulate important cellular functions. In addition, a variety of new evidence shows that [Mg2+]i instantaneously changes following stimulation with various biologically active substances. These observations suggest that [Mg2+]i may act as a second messenger.

Animals↗
PubMed1998

Effects of insulin and insulin-like growth factor-1 on intracellular magnesium of platelets.

Magnesium (Mg2+), the second most abundant intracellular cation, is a critical cofactor in numerous enzymatic reactions. After stimulation of platelets with insulin and insulin-like growth factor-1 (IGF-1), we examined changes in cytosolic free Mg2+ ([Mg2+]i) by using fluorescent probe magfura-2. Basal [Mg2+]i in platelets was 614 +/- 1 microM (mean +/- SEM, n = 60). Insulin and IGF-1 induced an immediate rise of [Mg2+]i in a dose-dependent manner. After stimulation of platelets with 100 microU/mL of insulin for 60 s, [Mg2+]i was significantly elevated to 1270 +/- 53 microM (n = 30, P < 0.05), i.e., 82 +/- 5% over resting [Mg2+]i. IGF-1 (5 micrograms/mL) also increased [Mg2+]i (1020 +/- 53 microM, 69 +/- 10% over resting [Mg2+]i, n = 30). In the medium containing choline instead of sodium or the medium without potassium, an elevation of [Mg2+]i with addition of insulin/IGF-1 was moderately suppressed. Amiloride, a Na+-H+ antiport inhibitor, did not block the insulin/IGF-1 effect. Insulin/ IGF-1 translocates Mg2+ from the extracellular space to intracellular space and these effects are affected by external sodium and potassium.

Amiloride↗
PubMed1998

A patient with congenital lipoid adrenal hyperplasia evaluated by serial abdominal ultrasonography.

UNLABELLED: Adrenal enlargement was followed by serial ultrasonography in an infant with congenital lipoid adrenal hyperplasia (lipoid CAH) from day 12 until 2 years and 4 months of age, when they were no longer detectable. Contrary to other types of CAH in which the configuration changes soon after replacement therapy, this infant with lipoid CAH showed persistent adrenal cortex enlargement due to massive accumulation of lipids and cholesterol resulting in a damaged glandular cyto-architecture. CONCLUSION: ultrasonographically persistent enlargement of the adrenals after replacement therapy is suggestive of the lipoid form of CAH.

Adrenal Cortex↗
PubMed1998

Relation between plasma nitrate and mean pulmonary arterial pressure in ventricular septal defect.

BACKGROUND: Nitric oxide (NO) is known to modulate myocardial contraction and coronary tone, and its inhalation reduces pulmonary vascular resistance in patients with pulmonary hypertension. OBJECTIVES: To evaluate the pathophysiological role of NO in patients with a ventricular septal defect (VSD). PATIENTS: Twenty-nine children with VSD, nine of whom had undergone VSD closure surgery, and 14 patients with Kawasaki disease. The mean age of the VSD patients was 3.1 years (range, 2 months to 9 years). METHODS: Using high performance liquid chromatography, nitrate (a more stable NO oxidation product) was measured in plasma specimens of the patients undergoing cardiac catheterisation. RESULTS: Nitrate concentrations in the pulmonary artery bore a significant relation to mean pulmonary artery pressure, pulmonary to systemic systolic pressure ratio, and pulmonary to systemic flow ratio. CONCLUSIONS: The concentration of nitrate was in proportion to the increment in intravascular or cardiac pressure, indicating that endogenous NO is upregulated as a compensatory homeostatic attempt to reduce pulmonary pressure and blood flow.

Analysis of Variance↗
PubMed1998

Transient left bundle branch block induced by left-sided cardiac catheterization in patients without pre-existing conduction abnormalities.

A traumatic left bundle branch block (LBBB) is uncommon in a patient with intact atrioventricular conduction. Three of our patients developed LBBB during a left-sided catheterization. Two patients suffered from angina pectoris and the other had an abdominal aneurysm. Two of them had a history of hypertension. None of the patients had ever shown any conduction abnormalities before the catheterization. The electrocardiogram just before the examination was normal in all 3 patients. LBBB was observed when a catheter was introduced into the left ventricle, and lasted 2--4 min without significant change in heart rates. Examination revealed no significant stenosis proximal to the first septal perforator and normal left ventricular contraction in all patients. One patient developed permanent LBBB 14 months later. Catheter-induced LBBB may occur easily with certain anatomical characteristics of the left bundle branch or the distal His bundle, with or without some concealed damage to the conduction system. It is important to keep this complication in mind and to pay adequate attention to patients' electrocardiograms as well as their angiographical findings, especially in those with pre-existing right bundle branch block.

Aged↗
PubMed1997

Plasma effects on phagocytic activity and hydrogen peroxide production by polymorphonuclear leukocytes in neonates.

To elucidate the defense mechanism in neonates against bacterial infections, phagocytic activity and hydrogen peroxide (H2O2) production by polymorphonuclear leukocytes (PMNs) in the whole blood and the effects of plasma on these functions were investigated on 44 healthy mature neonates (term 37 to 41 weeks) and 15 premature neonates (term 30 to 36 weeks) using two color flow cytometric analysis. The results were compared to those of a healthy adult control group (n = 10). PMN phagocytic activity was low in both mature and premature neonates. H2O2 production of PMN with phorbol myristate acetate (PMA) stimulation and following phagocytosis was augmented in both mature and premature neonates. When plasma and PMNs of adults and neonates were separated and combined differently, phagocytic activity and H2O2 production of PMNs appeared to be principally regulated by the plasma employed. This finding indicates that plasma has major effects on both phagocytosis and H2O2 production by PMNs of newborn neonates.

Adult↗
PubMed1997

Ménétrier's disease evaluated serially by abdominal ultrasonography.

We report the case of a 3-year-old boy with Ménétrier's disease who presented with prominent anasarca associated with hypoproteinemia, but no proteinuria. An early sonogram of the stomach demonstrated thickening of the gastric wall which was found to resolve gradually on serial sonograms. Consequently, we considered that the submucosal layer of the gastric wall was particularly thickened as a result of Ménétrier's disease. A gastric biopsy was performed 18 days after onset of the disease, and an electron-microscopic examination of the sample disclosed persistent widening of gastric tight junctions by more than 10 nm. The patient made a full recovery on supportive treatment in 3 weeks. Ultrasonography provided us with a potent tool not only in making the diagnosis, but also in following the course of the disease.

Abdomen↗
PubMed1997

Altered intracellular calcium and phorbol 12,13-dibutyrate binding to intact platelets in young obese subjects.

The study was designed to examine cytosolic free calcium ((Ca2+)i) and phorbol dibutyryl ester binding in intact platelets of young obese subjects as compared with the platelets of age-matched subjects with non-insulin-dependent diabetes mellitus (NIDDM) and those of healthy control subjects. The assay was studied in basal and thrombin-stimulated conditions. The binding parameter of phorbol ester is a criterion for active protein kinase C (PKC) units in the platelet plasma membrane. The resting (Ca2+)i correlated with body mass index (BMI)(r = 0.385, p = 0.0034) and plasma insulin level (r = 0.316, p = 0.0269), and the resting (Ca2+)i level was higher in the obesity group (160.6 +/- 15.8 nmol/L; n = 25) than controls (78.9 +/- 7.6 nmol/L; n = 24, p < 0.0001). Among the obesity and control groups, there was a correlation between BMI and fasting plasma insulin level (r = 0.399, p = 0.0237). Systolic blood pressure correlated with BMI(r = 0.504, p = 0.0005). The mean systolic blood pressure of the obesity group was higher than those of the other two groups. The mean Hill coefficient for thrombin-treated platelets of phorbol dibutyrate binding was higher in the obesity group when compared with healthy controls and the subjects with NIDDM (1.47 +/- 0.21 vs 1.06 +/- 0.16 and 0.99 +/- 0.09, respectively; p < 0.05). In conclusion, young subjects with simple obesity have already developed altered platelet Ca2+ regulation that is usually observed in adult patients with a number of metabolic diseases. These data are interpreted to indicate that a relationship exists between dysregulation of PKC and impaired glucose tolerance that precedes other complications of obesity.

Adolescent↗
PubMed1997

Increased intracellular calcium and altered phorbol dibutyrate binding to intact platelets in young subjects with insulin-dependent and non-insulin-dependent diabetes mellitus.

Intracellular calcium ([Ca2+]i) and phorbol ester binding were studied in intact platelets of young patients with insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus. Our objective was to evaluate disturbances in calcium regulation and signal transduction in platelets of diabetics. [Ca2+]i in platelets of the IDDM group (135 +/- 20 nmol/L) under basal conditions was significantly higher than that of the control group (81 +/- 8 nmol/L, P = .019), whereas at 60 seconds after stimulation with 0.1 National Institutes of Health (NIH) U/mL thrombin, [Ca2+]i in the NIDDM group (484 +/- 36 nmol/L) was significantly higher than that of the controls (347 +/- 22 nmol/L, P = .003) and IDDM group (360 +/- 45 nmol/L, P = .04), respectively. Phorbol 12,13-dibutyrate (PdBu) maximal binding capacity (Bmax) in the IDDM group was significantly lower than that in the control group either under basal conditions or after stimulation with thrombin (P = .0034 and P = .015, respectively). Bmax in the NIDDM group was significantly lower than that in the controls only after stimulation with thrombin (P = .047). The Kd for PdBu of the IDDM group was lower than that of the control group under basal conditions (P = .017). When analyzing the pooled data of all subjects, a significant correlation was observed between Bmax and Kd (under basal conditions, r = .544, P < .0001; after stimulation, r = .601, P < .0001). Our results support the idea that the increased affinity for PdBu may compensate for the decreased binding capacity. We interpret the data as indicating that the change in the binding of phorbol ester to protein kinase C (PKC) units may result in an altered PKC/calcium interaction in the pathogenesis of diabetes mellitus. Our study indicates that such metabolic derangements of [Ca2+]i have already been developing in young diabetic patients.

Adolescent↗
PubMed1996

Application of percutaneous transluminal coronary angioplasty to coronary arterial stenosis in Kawasaki disease.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) has rarely been performed on patients with coronary lesions that result from Kawasaki disease. In this study, we retrospectively evaluated the effectiveness of PTCA in five patients with coronary arterial stenosis that resulted from Kawasaki disease and reviewed previous reports for possible indicators of PTCA effectiveness. METHODS AND RESULTS: Five patients, ranging in age from 2 to 16 years (median 8 years) underwent conventional PTCA for localized stenosis. The lesion targeted for PTCA was located in the middle right coronary artery of three patients and in the left anterior descending artery in two patients. In four of the five patients, PTCA was angiographically effective, with stenosis rates improving from 84 +/- 10% to 33 +/- 11% (P<.05). When the previously reported cases of six similar patients were taken into consideration, the only predictor of successful PTCA seemed to be the time elapsed between the onset of Kawasaki disease and performance of this procedure. CONCLUSIONS: In cases in which patients show significant localized stenosis as a result of Kawasaki disease, PTCA should be attempted within 6 to 8 years of the onset of the disease. Additionally, intravascular ultrasound imaging was found to be a useful tool for evaluating internal morphology before and after PTCA. In older patients with coronary calcification, other alternatives to PTCA, such as the use of a rotablator or an atherectomy catheter, should be considered.

Adolescent↗