The distribution of fasting and non-fasting serum triglyceride levels in Japanese population.
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Fasting↗
Biomedical subjects
Osamu Miyazaki
Publications and source records attributed to Osamu Miyazaki.
A novel ELISA system for selective measurement of human adiponectin multimers by using proteases.
BACKGROUND: Adiponectin, an antiatherogenic adipocyte-derived protein exists in human blood as multiple isoforms--trimeric low molecular weight (LMW), albumin-binding LMW (Alb-LMW), hexameric middle molecular weight (MMW), and high molecular weight (HMW) forms. We developed a novel ELISA system to detect total human adiponectin and the selective level of each adiponectin multimer for investigating the distribution of these levels in human blood. METHODS: Two monoclonal antibodies that were raised against human adiponectin were used to construct a sandwich ELISA to measure adiponectin levels. Adiponectin multimers were selectively measured after sample pretreatment with two proteases that specifically digested the trimeric forms or both the hexameric and trimeric forms. RESULTS: The ELISA had a dynamic range of 0.075-4.8 ng/ml. Intraassay variations (CV) were 5.3% (total adiponectin), 4.1% (MMW+HMW), and 3.3% (HMW). Comparison of the results of ELISA and quantitative western blot analysis of multimeric adiponectin in serum samples revealed good correlation (LMW+Alb-LMW, r=0.873; MMW, r=0.907; HMW, r=0.950). Each of the three forms of adiponectin multimer levels closely correlated with total adiponectin levels in healthy subjects. CONCLUSIONS: This ELISA system can be used to further investigate the physiological roles of human adiponectin multimers.
Adiponectin↗
Serum amyloid A (SAA)-induced remodeling of CSF-HDL.
Inflammation is a risk factor for Alzheimer's disease. Serum amyloid A (SAA) is an acute phase protein that dissociates apolipoprotein AI (apoAI) from plasma HDL. In cerebrospinal fluid (CSF), the SAA concentration is much higher in subjects with Alzheimer's disease than in controls. CSF-HDL is rich in apoE, which plays an important role as a ligand for lipoprotein receptors in the central nervous system (CNS). To clarify whether SAA dissociates apoE from CSF-HDL, we added recombinant SAA to CSF and determined the apoE distribution in the CSF using native two-dimensional gel electrophoresis. We found that SAA dissociated apoE from CSF-HDL in a dose-dependent manner. This effect was more evident in apoE4 carriers than in apoE3 or apoE2 carriers. After a 24-h incubation at 37 degrees C, SAA continuously dissociated apoE from CSF-HDL. Amyloid beta (Abeta) fragments (1-42) were bound to large CSF-HDL but not to apoE dissociated by SAA. In conclusion, SAA dissociates apoE from CSF-HDL. We postulate that inflammation in the CNS may impair Abeta clearance due to the loss of apoE from CSF-HDL.
Alzheimer Disease↗
Improvement of low-contrast detectability in low-dose hepatic multidetector computed tomography using a novel adaptive filter: evaluation with a computer-simulated liver including tumors.
PURPOSE: The purpose of this study was to investigate how much radiation dose can be reduced without loss of low-contrast detectability with a newly developed adaptive noise reduction filter in hepatic multidetector computed tomography (MDCT) scans by using a computer-simulated liver phantom. MATERIALS AND METHODS: Simulated CT images, including liver and intrahepatic tumors, were mathematically constructed using a computer workstation to evaluate low-contrast detectability by the observer performance test. Milliampere second for construction of simulated images were 60, 80, 100, and 120 mAs (low dose) and 160 mAs (standard dose) at 120 kVp. Images with 60, 80, 100, and 120 mAs were postprocessed with the adaptive noise reduction filter. A total of 432 images were prepared and receiver operating characteristic (ROC) analysis was performed by 5 radiologists. The detectability of simulated tumor by radiologists was estimated with the area under the ROC curves (Az values). In addition, we visually evaluated CT images of 15 patients with chronic liver damage for graininess of the liver parenchyma, sharpness of the liver contour, conspicuity and marginal sharpness of the liver tumors, and overall image quality. RESULTS: The mean Az value at 0.777 (60 mAs), 0.828 (80 mAs), and 0.844 (100 mAs) without filter was significantly lower than that of 160 mAs without filter (P < 0.001, 60 mAs; P = 0.010, 80 mAs; P = 0.040, 100 mAs). There was no statistical difference between the mean Az value at 80 mAs with and 160 mAs without the adaptive noise reduction filter (P = 0.220) and 100 mAs with and 160 mAs without the adaptive noise reduction filter (P = 0.979). In the visual evaluation of patient livers, there was no statistical difference in the graininess and sharpness of the liver, the conspicuity and marginal sharpness of the tumor, and the overall image quality between standard-dose and filtered low-dose images (Wilcoxon signed rank test, P > 0.05). CONCLUSION: The radiation dose can be reduced by 50% without loss of nodule detectability by applying the adaptive noise reduction filter to simulated and patient liver images obtained at MDCT.
Aged↗
Measurement of the high-molecular weight form of adiponectin in plasma is useful for the prediction of insulin resistance and metabolic syndrome.
OBJECTIVE: The high-molecular weight (HMW) form of adiponectin, an adipocyte-derived insulin-sensitizing hormone, has been reported to be the most active form of this hormone. We investigated whether measurement of plasma HMW adiponectin levels, using our newly developed enzyme-linked immunosorbent assay system for selective measurement of human HMW adiponectin level, may be useful for the prediction of insulin resistance and metabolic syndrome. RESEARCH DESIGN AND METHODS: A total of 298 patients admitted for diabetes treatment or coronary angiography served as study subjects. Receiver operator characteristic (ROC) curves for the HMW ratio (HMWR; ratio of plasma level of HMW adiponectin to that of total adiponectin) and plasma total adiponectin levels were plotted to predict the presence of insulin resistance and metabolic syndrome. RESULTS: The area under the ROC curve (AUC) of the HMWR values to predict the presence of insulin resistance was significantly larger than that of plasma total adiponectin level in total subjects (0.713 [95% CI 0.620-0.805] vs. 0.615 [0.522-0.708], P = 0.0160). The AUC for the HMWR values to predict the presence of metabolic syndrome was significantly larger than that for plasma total adiponectin levels in men (0.806 [0.747-0.865] vs. 0.730 [0.660-0.800], P = 0.0025) and in women (0.743 [0.659-0.828] vs. 0.637 [0.532-0.742], P = 0.0458). CONCLUSIONS: The HMWR value has better predictive power for the prediction of insulin resistance and metabolic syndrome than plasma total adiponectin level.
Adiponectin↗
A computer-simulated liver phantom (virtual liver phantom) for multidetector computed tomography evaluation.
OBJECTIVE: The purpose of study was to develop a computer-simulated liver phantom for hepatic CT studies. A computer-simulated liver phantom was mathematically constructed on a computer workstation. MATERIALS AND METHODS: The computer-simulated phantom was calibrated using real CT images acquired by an actual four-detector CT. We added an inhomogeneous texture to the simulated liver by referring to CT images of chronically damaged human livers. The mean CT number of the simulated liver was 60 HU and we added numerous 5-to 10-mm structures with 60+/-10 HU/mm. To mimic liver tumors we added nodules measuring 8, 10, and 12 mm in diameter with CT numbers of 60+/-10, 60+/-15, and 60+/-20 HU. Five radiologists visually evaluated similarity of the texture of the computer-simulated liver phantom and a real human liver to confirm the appropriateness of the virtual liver images using a five-point scale. RESULTS: The total score was 44 in two radiologists, and 42, 41, and 39 in one radiologist each. They evaluated that the textures of virtual liver were comparable to those of human liver. CONCLUSIONS: Our computer-simulated liver phantom is a promising tool for the evaluation of the image quality and diagnostic performance of hepatic CT imaging.
Computer Simulation↗
Renovascular hypertension complicated with VATER association.
We report herein a case of a girl with renovascular hypertension associated with VATER association. Her plasma renin activity and aldosterone were high. The ultrasonic echogram and renogram revealed a right hypoplastic kidney without function and a normal-sized left kidney with normal function. Renal angiography revealed a small diameter right main renal artery and a normal left main renal artery with segmental stenosis of left branching renal arteries in the middle segment. Selective renal vein sampling indicated that renin secretion was primarily from the left kidney. This is the first report of renovascular hypertension complicated with VATER association.
Abnormalities, Multiple↗
[Current practice of pediatric MDCT in Japan: survey results of demographics and age-based dose reduction].
PURPOSE: To assess the current practice of pediatric MDCT in Japan, with particular reference to age-related dose adjustment. MATERIALS AND METHODS: During the first three months of 2004, a questionnaire was mailed to 996 institutions, among which listed MDCT users ranged from private hospitals to large university-based hospitals. RESULTS: We received responses from 348 (34.9%) institutions. Fifty-three percent of the respondents had four-detector MDCT units. Approximately 70% of examinations were head and 22% were body. Scanning parameters were determined by full-time radiologists in 40%, and by CT technologists in 28% of respondents. Eighty-nine percent (head CT) and 85% (abdominal CT) of respondents indicated that they changed parameters for children. More than 90% changed tube current for optimization. Change was based on the technologist's experience (56%, head CT; 43%, abdominal CT), and automatic exposure control has been used as a basis of mAs control in 17% of respondents for head CT and in 34% for abdominal CT. Age-related mAs settings for abdominal CT were almost the same as those published in a United States survey. CONCLUSION: Although Japan has approximately 40% of the world's CT units, optimized pediatric MDCT settings might be moved away from a fixed mA protocol as recommended by the FDA and in conformity with the ALARA (as low as reasonably achievable) concept.
Adolescent↗
Physical fitness and reverse cholesterol transport.
BACKGROUND: Physical exercise is associated with a decreased risk of cardiovascular disease, which may be partly caused by the effect of exercise on the lipoprotein profile. The most consistent effect of exercise on lipoprotein metabolism is an increase in high-density lipoprotein (HDL). METHODS AND RESULTS: Parameters of reverse cholesterol transport (RCT) in 25 endurance-trained male athletes were compared with 33 age-matched males enjoying an active lifestyle. VO2max was higher in athletes than in controls (53.4+/-1.2 versus 38.8+/-1.0 mL/min per kg; P<0.01). The following differences in parameters of RCT were found: (1) plasma HDL cholesterol and apoA-I levels were higher in athletes compared with controls (1.7+/-0.1 versus 1.4+/-0.1 mmol/L; P<0.001; and 145+/-2 versus 128+/-3 mg/dL; P<0.001, respectively). Both correlated with VO2max up to the value of 51 mL/min per kg; (2) prebeta1-HDL was higher in athletes than in controls (54+/-4 versus 37+/-3 microg/mL; P<0.001) and correlated positively with VO2max; (3) lecithin cholesterol: acyltransferase activity was higher in athletes (29.8+/-1.2 versus 24.2+/-1.4 nmol/microL per hour; P<0.005); and (4) the capacity of plasma to promote cholesterol efflux from macrophages was higher in athletes (18.8%+/-0.8% versus 16.2%+/-0.3%; P<0.03). CONCLUSIONS: The likely reason for higher HDL concentration in physically fit people is increased formation of HDL from apoA-I and cellular lipids.
Adult↗
Neonatal goiter with congenital thyroid dysfunction in two infants diagnosed by MRI.
It is essential to diagnose thyroid dysfunction at an early stage because congenital hypothyroidism (CH) represents one of the most common preventable causes of delayed physical and psychological development, including mental retardation. US evaluates the shape of the thyroid gland. CT and scintigraphic examinations demonstrate iodine metabolism of the thyroid, but there is associated radiation exposure. We encountered two cases of congenital goiter, in which MRI was very helpful in confirming thyroid dysfunction and was very useful in making an accurate diagnosis.
Diagnosis, Differential↗
LCAT-dependent conversion rate is a determinant of plasma prebeta1-HDL concentration in healthy Japanese.
BACKGROUND: Prebeta1-HDL acts as a primary acceptor of cellular cholesterol. Prebeta1-HDL is converted into alpha-migrating high-density lipoprotein (HDL) by lecithin/cholesterol acyltransferase (LCAT). We examined whether the LCAT-dependent conversion rate of prebeta1-HDL is a determinant of the plasma prebeta1-HDL concentration in healthy Japanese. METHODS: We measured the conversion half time (CHT(prebeta1)), the time required for 50% of baseline prebeta1-HDL to be changed into alpha-migrating HDL by LCAT, in 100 healthy Japanese (47 men, 53 women, 22-88 years). RESULTS: Prebeta1-HDL concentration, as determined by immunoassay, was significantly lower in younger women (<50 years, n=24) than in older women (>or=50 years, n=29) (16.8+/-3.3 vs. 21.7+/-8.0 mg/l apolipoprotein AI (apoAI), p<0.01). There was no significant difference in prebeta1-HDL concentration between younger (n=24) and older (n=23) men (21.2+/-6.8 vs. 22.5+/-6.6 mg/l apoAI). The mean CHT(prebeta1) for all subjects was 47.4+/-13.0 min, and was not influenced by gender or age. Prebeta1-HDL concentration was positively correlated with CHT(prebeta1) in both men and women, suggesting that high prebeta1-HDL levels may reflect delayed conversion of prebeta1-HDL. CONCLUSION: LCAT-dependent conversion rate is a determinant of plasma prebeta1-HDL concentration in healthy Japanese. We speculate that prebeta1-HDL concentration may be used as a metabolic marker for HDL maturation.
Adult↗
LCAT-dependent conversion of prebeta1-HDL into alpha-migrating HDL is severely delayed in hemodialysis patients.
Prebeta1-HDL is a minor HDL subfraction that acts as an efficient initial acceptor of cell-derived free cholesterol. During 37 degrees C incubation, plasma prebeta1-HDL decreases over time due to its conversion to alpha-migrating HDL by lecithin:cholesterol acyltransferase (LCAT). This conversion may be delayed in hemodialysis patients who have decreased LCAT activity. To clarify whether LCAT-dependent conversion of prebeta1-HDL to alpha-migrating HDL is delayed in hemodialysis patients, prebeta1-HDL concentrations were determined in 45 hemodialysis patients and 45 gender-matched control subjects before and after 37 degrees C incubation with and without the LCAT inhibitor. It was found that the baseline prebeta1-HDL concentration in hemodialysis patients was more than twice that in the controls (44.9 +/- 21.4 versus 19.8 +/- 6.7 mg/L apoAI; P < 0.001). After 2-h incubation, the LCAT-dependent decrease in prebeta1-HDL in hemodialysis patients was about one-third of that in the controls (30 +/- 27 versus 97 +/- 17% of baseline; P < 0.01). The LCAT-dependent rate of decrease in prebeta1-HDL levels (DR(prebeta1)) was the same for samples from hemodialysis patients exhibiting normal (> or =1.03 mmol/L) and low HDL-cholesterol levels (32 +/- 32 versus 28 +/- 23% of baseline; NS). DR(prebeta1) was positively correlated with LCAT activity (r = 0.617; P < 0.001). In conclusion, the LCAT-dependent conversion of prebeta1-HDL to alpha-migrating HDL is severely delayed in hemodialysis patients. The impaired catabolism of prebeta1-HDL may accelerate atherosclerosis in hemodialysis patients.
Adult↗
Analytical performance of a sandwich enzyme immunoassay for pre beta 1-HDL in stabilized plasma.
We have established an immunoassay for pre beta 1-HDL (the initial acceptor of cellular cholesterol) using a monoclonal antibody, MAb55201. Because pre beta 1-HDL is unstable during storage, fresh plasma must be used for pre beta 1-HDL measurements. In this study, we describe a method of stabilizing pre beta 1-HDL, and evaluate the analytical performance of the immunoassay for pre beta 1-HDL. Fresh plasma was stored under various conditions with or without a pretreatment consisting of a 21-fold dilution into 50% (v/v) sucrose. Pre beta 1-HDL concentration was measured by immunoassay. In nonpretreated samples, pre beta 1-HDL decreased significantly from the baseline after 6 h at room temperature. Although pre beta 1-HDL was more stable at 0 degrees C than at room temperature, it increased from 30.2 +/- 8.5 (SE) to 56.5 +/- 5.5 mg/l apolipoprotein A-I (apoA-I) (P < 0.001) in hyperlipidemics, and from 18.4 +/- 1.2 to 37.9 +/- 3.3 mg/l apoA-I (P < 0.001) in normolipidemics after 5-day storage. After 30-day storage at -80 degrees C, pre beta 1-HDL increased from 29.0 +/- 4.0 to 38.0 +/- 5.7 mg/l apoA-I (P < 0.001) in hyperlipidemics, whereas it did not change in normolipidemics. In pretreated samples, pre beta 1-HDL concentration did not change significantly under any of the above conditions. Moreover, pre beta 1-HDL concentrations determined by immunoassay correlated with those determined by native two-dimensional gel electrophoresis (n = 24, r = 0.833, P < 0.05). An immunoassay using MAb55201 with pretreated plasma is useful for clinical measurement of pre beta 1-HDL.
Electrophoresis, Gel, Two-Dimensional↗
Delineation of the role of pre-beta 1-HDL in cholesterol efflux using isolated pre-beta 1-HDL.
OBJECTIVE: The role of pre-beta1-high density lipoprotein (pre-beta1-HDL) in cholesterol efflux was investigated by separating human plasma into purified pre-beta1-HDL and pre-beta1-HDL-deficient plasma by using a monoclonal antibody specifically reacting with pre-beta1-HDL. METHODS AND RESULTS: When compared with whole plasma, pre-beta1-HDL-deficient plasma was equally efficient in promoting cholesterol efflux from human skin fibroblasts and THP-1 human macrophage cells. When added at the same apolipoprotein A-I concentration, pre-beta1-HDL was less effective than whole plasma in promoting cholesterol efflux from fibroblasts but equally effective in promoting cholesterol efflux from THP-1 cells. However, pre-beta1-HDL-deficient plasma reconstituted with 16% pre-beta1-HDL was more active than whole plasma, demonstrating that pre-beta1-HDL does promote cholesterol efflux actively. The amount of cellular cholesterol present in reisolated pre-beta1-HDL was 1.5- to 2-fold greater after incubation of the cells with whole plasma than after incubation of the cells with pre-beta1-HDL-deficient plasma or plasma treated with the anti-pre-beta1-HDL antibody. However, the anti-pre-beta1-HDL antibody did not inhibit cholesterol efflux. CONCLUSIONS: We conclude that whereas pre-beta1-HDL is capable of taking up cellular cholesterol, its presence in plasma is not essential for cholesterol efflux, at least in vitro. Instead, pre-beta1-HDL may be the first product of apolipoprotein A-I lipidation during the formation of HDL but may not play a major role in transferring cellular cholesterol to HDL.
Antibodies, Monoclonal↗
A rare case of Salmonella soft-tissue abscess.
A healthy 6-year-old boy had complained of fever and chest pain for 3 days. On admission, he had a mass on the sternum, 3.7 x 2.5 cm in size. Abnormal laboratory findings included a white blood cell count of 12,900/microl, erythrocyte sedimentation rate (ESR), 74 mm/h, and C-reactive protein (CRP), 9.7 mg/dl. Ultrasound examination of the chest revealed a hypoechoic lesion on the sternum that was 30 x 15 mm in size. Chest computed tomography (CT) scan showed no bone fracture or bone erosion. The patient received cefpirome, given intravenously at 60 mg/kg per day for 10 days. Incision and drainage was performed on the seventh day in the hospital, and we collected 0.5 ml of pus. Salmonella enteritidis was detected from the drainage. However, the patient had no gastrointestinal symptoms. He was discharged on the fourteenth hospital day, as he was asymptomatic. Results of all physical and laboratory examinations including blood and stool cultures and ultrasound examinations, were within the normal limits upon discharge.
Abscess↗