Search PubMed⌕ Search

Biomedical subjects

Y Nakaya

Publications and source records attributed to Y Nakaya.

At least 37 records · Page 2Linked to original sources
PubMed2001

Dietary phosphorus restriction reverses the impaired bone mineralization in vitamin D receptor knockout mice.

Deficiency of vitamin D, which is required for calcium homeostasis, causes rickets with hypocalcemia and hypophosphatemia, resulting in growth retardation and impaired bone formation. Mice lacking the vitamin D receptor (VDR) develop the typical features of rickets, establishing that VDR plays a role in controlling the actions of vitamin D. Normalization of impaired mineral homeostasis in VDR KO mice fed a diet supplemented with high concentrations of calcium (2%) and phosphorus (1.25%) is reported to reverse the malformation of bone and the growth retardation as well. However, the relationship between mobilization of phosphorus and calcium and nuclear control of vitamin D actions remains unclear. The present study was undertaken to determine the effect of dietary phosphorus on mineral mobilization and bone mineralization. We report here that feeding a diet supplemented with a restricted amount of phosphorus (0.25%) and a normal amount of calcium (0.5%) for 4 weeks reverses the growth retardation and the impaired mineralization in VDR KO mice, as does a high-calcium and high-phosphorus diet (Ca: 2%; P: 1.25%). Thus, the present study suggests that mobilization of calcium and mobilization of phosphorus are differentially regulated through vitamin D-dependent and -independent systems, and that intake of calcium and phosphorus in the proper ratio is important for mineral homeostasis and bone mineralization.

Animals↗
PubMed2001

The nutritional status of elderly bed-ridden patients receiving tube feeding.

Long-term enteral feeding by tube has become a frequently used procedure in elderly patients. However, only a few studies dealing with the nutritional assessment of such patients are currently available. This study was designed to clarify this issue. Anthropometric and biochemical variables, energy expenditure and dietary intake were investigated in 44 hospitalized bed-ridden patients with and without tube feeding over 65 years of age and 41 age-matched free-eating elders in a nursing home. All patients with tube feeding received enteral nutrition by nasogastric tube. The body weight, body mass index, mid-upper-arm circumference, arm muscle circumference and serum level of albumin were significantly lower in the patients with and without tube feeding, compared with free-eating elders of both genders (p<0.05). Energy intakes of the patients with tube feeding were 1,171+/-286 kcal/d (about 26 kcal/kg/d), which is comparable to the predicted total energy expenditure (1.2 x basal energy expenditure). Protein intake was 44.9+/-13.1 g/d (about 1.0 g/kg/d) and the percentage of protein per total energy was 15%. These intakes are generally considered to be optimal for bed-ridden patients receiving tube feeding. However, the incidence of protein-malnutrition, as evidenced by decreased arm muscle circumference (<80% of normal) and hypoalbuminemia (<35 g/L), in the patients with tube feeding was significantly higher than that in the healthy elders. In addition, the orally fed bed-ridden patients were also malnourished, suggesting that the bed-ridden patients easily became malnourished even if they were fed energy and protein which approximated calculated predicted values. These findings raise a problem concerning nutritional management of bed-ridden patients.

Aged↗
PubMed2001

Interferon-gamma activates outwardly rectifying chloride channels in the human bronchial epithelial cell line BEAS-2B.

The mechanism of increased chloride currents by inflammatory cytokine, interferon-gamma (IFN-gamma), was investigated in cultured a human bronchial epithelial cell line (BEAS-2B) using cell-attached and inside-out patch configurations. The channel sensitive to chloride ion was activated by forskolin, an activator of adenylate cyclase, or 100 microM dibutyryl 5'-cyclic monophosphate in cell-attached configurations. The conductance of this channel was 40 +/- 4 pS in symmetrical 150 mM chloride solution between membrane potentials of 0 to mV, and this channel was blocked by 500 microM 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), suggesting that this channel was an outwardly rectifying chloride channel (ORCC). Treatment of 10-1000 U/ml IFN-gamma for 3 hours, but not IFN-alpha, significantly increased channel activities of ORCC, and this activation was observed at least 24 hours after treatment. Erythromycin, a macrolide antibiotic, at a concentration of 100 microM inhibited the activation of ORCC induced by IFN-gamma. The findings of the present study indicate that increased mucus secretion during inflammation might be partly due to activation of chloride permeability by cytokine and erythromycin might improve oversecretion of mucus from bronchial epithelium by blocking ORCC.

Bronchi↗
PubMed2001

Autonomic nervous function in patients with peptic ulcer studied by spectral analysis of heart rate variability.

This study is intended to clarify the relationship between occurrence of peptic ulcer disease and dysfunction of the autonomic nervous system. We studied heart rate variability and assessed the circadian rhythm of autonomic nervous function in 20 patients with peptic ulcer (PU group) and 20 age-matched healthy controls (N group) using 24-hour Holter monitoring. Moreover, the relationship between gastric juice secretion and autonomic activity was examined under intravenous injection of insulin or butylscopolamine in adult mongrel dogs. High frequency spectral (HF) power, an indicator of parasympathetic tone, was increased markedly at night in the PU group. Low frequency spectral (LF) power, an indicator of sympathetic tone modified by vagal tone, was higher during the day than at night in the N group, whereas this normal circadian rhythm of LF power disappeared in 11 cases (55%) in the PU group. In addition, the LF power was increased significantly at night (p<0.01) in the PU group. HF power and gastric juice secretion was increased by the administration of insulin. High sympatho-vagal tone at night may result in spasm of gastric arteries and excess secretion of gastric acid in the PU group. These results suggest that the nocturnal acceleration of LF, HF, and LF/HF is related to peptic ulcer diseases.

Adult↗
PubMed2001

Evaluation of the total health promotion plan in Japan, as related to health promotion effects and the prevention of lifestyle-related diseases.

The present study was undertaken to investigate whether health-promoting activities in Japan are useful for preventing the development of lifestyle-related diseases and for promoting health. One thousand, one hundred and sixty-seven Japanese workers were given a medical health check and had their maximum oxygen uptake measured according to the total health promotion plan (THP) protocol, which the Japanese Ministry of Health, Labor and Welfare is actively planning. Correlations between the maximum oxygen uptake and performance on health check items were statistically evaluated. The maximum oxygen uptake was positively correlated with the duration of a worker's ability to stand on one leg, and on the frequency with which they performed upper body weight lifting. In addition, the maximum oxygen uptake was negatively correlated with age, body weight, thickness of subcutaneous fat in the upper arms and shoulders, body fat ratios, body mass index (BMI), maximum and minimum blood pressures, resting heart rates, and total cholesterol levels. Moreover, the maximum oxygen uptake tended to be significantly higher in both male and female subjects who exercised regularly. It is suggested that maximum oxygen uptake and regular exercising play important roles in the inhibition of risk factors for ischemic heart diseases. Therefore, we believe the THP can play an important role in the primary prevention of lifestyle-related diseases. The purpose of the THP in Japan is to promote the achievement of healthy lifestyles in individual subjects, both from mental and physical perspectives. These results suggest that such efforts may help prevent the development of lifestyle-related diseases.

Adult↗
PubMed2000

Induction of inducible nitric oxide synthase by ginsenosides in cultured porcine endothelial cells.

Mechanism of Nitric oxide (NO) production by ginsenosides was investigated in cultured porcine endothelial cells. Beta-nicotinamide adenine dinucleotide phosphate (beta-NADPH) staining showed that the NO production was significantly enhanced by the presence of 40 microg/ml ginsenosides with 10 microM L-arginine after 12 h incubation. NO production was suppressed by addition of 0.5 microM Nomega-Nitro-L-arginine (L-NNA), an inhibitor of NO synthases (NOSs), to the incubation medium. In addition, the immunoreactive signals of inducible NOS (iNOS) were appeared in endothelial cells after 12-h incubation of ginsenosides, whereas the signals were not observed in non-treated cells. Our findings suggest that ginsenosides can enhance NO production by induction of iNOS in addition to its direct effect on endothelial cells by increasing intracellular Ca2+ concentration.

Animals↗
PubMed2000

A novel 31-amino-acid-length endothelin, ET-1(1-31), can act as a biologically active peptide for vascular smooth muscle cells.

Human chymase produces a novel endothelin-1 with 31 amino-acid length ¿ET-1(1-31)¿, which is longer than conventional ET-1, ¿ET-1(1-21)¿. The aim of our study was to investigate the role of ET-1(1-31) on porcine coronary vascular smooth muscle cell (VSMC). Although the increase in [Ca(2+)](i) by ET-1(1-31) was 10 times weaker than that of ET-1(1-21), ET-1(1-31) showed equivalent potency in VSMC proliferation, c-fos/c-myc mRNA expression and cell cycle analysis with ET-1(1-21). ET-1(1-31) significantly induced expression of cyclin D1 but not those of cyclin D2 or D3. These effects were specifically inhibited by BQ485, an ET(A) receptor antagonist, although that of ET-1(1-21) was not specific to BQ485, suggesting different receptor specificity from ET-1(1-21). These results indicate that ET-1(1-31) also can involve a VSMC proliferation process such as atherosclerosis, although it has weaker vasoconstricting potency and different receptor subtypes on VSMC from those of ET-1(1-21).

Animals↗
PubMed2000

Effect of a novel vasoconstrictor endothelin-1 (1-31) on human umbilical artery.

To clarify the action of a novel endothelin-1 with 31 amino acids, ET-1 (1-31), on fetal circulation, its vasoconstrictive activity on human umbilical and uterine arteries was investigated in comparison with that of a conventional ET-1 (1-21). UFER micro-easy magnus was used for determination of vasoconstriction. The contraction of umbilical artery by KCl was significantly weaker than that of the uterine artery. In ETs, constriction by KCl was set as control, and the rate of constriction of uterine and umbilical arteries was used for comparison. The constriction of human uterine artery induced by ET-1 (1-31) was also significantly weaker than that by ET-1 (1-21). On the contrary, ET-1 (1-31) was a potent constrictor on the umbilical artery equally to ET-1 (1-21). The present study is the first to demonstrate that ET-1 (1-31) has a contractile activity on human vessels. Furthermore, the regulatory mechanism on constriction of umbilical artery is different from that observed in a systemic vessel, indicating a particularly important role of ET-1 (1-31) in fetal circulation.

Adult↗
PubMed2000

Influenza A and B viruses expressing altered NS1 proteins: A vaccine approach.

We propose a rational approach to the generation of live viral vaccines: alteration of virally encoded type I IFN antagonists to attenuate virulence while retaining immunogenicity. We have explored this concept by using the influenza virus. Previously we have shown that the NS1 protein of influenza A virus possesses anti-IFN activity. We now present evidence that influenza A and B viruses encoding altered viral NS1 proteins are highly attenuated in the mouse host, yet provide protection from challenge with wild-type viruses.

Animals↗
PubMed2000

The lipoprotein lipase activator, NO-1886, suppresses fat accumulation and insulin resistance in rats fed a high-fat diet.

AIMS/HYPOTHESIS: Fat balance is critical in the aetiology of obesity and related diseases. Lipoprotein lipase is of major importance in lipid metabolism. The aim of this study was to investigate the long-term effects of the lipoprotein lipase activator, NO-1886, on substrate utilisation, adiposity and insulin action in rats fed a high-fat diet. METHODS: Male, Sprague-Dawley rats were fed for 10 weeks on a chow diet or a high-fat diet with, or without, NO-1886 (50 mg x kg(-1) x day(-1)). Weight gain, fat accumulation and both hormone-sensitive and lipoprotein, lipase activities were measured. Insulin action was assessed by the euglycaemic hyperinsulinaemic clamp and metabolic rate/substrate utilisation by open-circuit respirometry. RESULTS: Compared with chow-fed controls, a high-fat diet increased weight gain, an effect lessened by NO-1886 [weight gain (g): chow, 37 +/- 3, high-fat, 222 +/- 9; high-fat + NO-1886, 109 +/- 6, all groups differed p < 0.001]. A similar pattern existed for fat accumulation [visceral fat (g): chow, 35.9 +/- 3.2; high-fat, 81.9 +/- 6.6; high-fat + NO-1886, 52.3 +/- 4.7, p < 0.01 high-fat vs the other groups]. A high-fat diet induced wholebody insulin resistance (clamp glucose infusion rate: 4.8 +/- 1.3 mg x kg(-1) x min(-1) vs 10.6 +/- 1.1 for the chow group, p < 0.01) with NO-1886 lessening this effect (8.3 +/- 0.5, p < 0.05 vs high-fat). The 24-h respiratory quotient was lower in the high-fat + NO-1886 group (0.825 +/- 0.010) compared with high-fat alone (0.849 +/- 0.004, p < 0.05). A high-fat diet increased lipoprotein and hormone-sensitive, lipase activities in epididymal fat, an effect not altered by NO-1886. In myocardium and skeletal muscle a high-fat diet lowered lipoprotein lipase activity, an effect lessened by NO-1886. CONCLUSION/INTERPRETATION: Lipoprotein lipase activators could have potential benefits for the treatment of obesity by increasing fat utilisation.

Adipose Tissue↗
PubMed2000

Early diagnosis of interferon-induced myocardial disorder in patients with chronic hepatitis C: evaluation by myocardial imaging with 123I-BMIPP.

Interferon (IFN) therapy for chronic hepatitis C is sometimes associated with cardiac complications. In the present study, we performed myocardial imaging with 123I-labeled beta-methyl-p-iodophenylpentadecanoic acid (123I-BMIPP) in order to evaluate myocardial disorders caused by IFN. We studied 40 healthy subjects (H group) and 25 patients with chronic hepatitis C who had been treated with IFN (IFN group). A Holter electrocardiogram (ECG) was performed and the autonomic nervous function was assessed by analyzing the spectral variability and 1/f fluctuation of heart rate. Myocardial planner imaging with 123I-BMIPP was performed to obtain the time activity curve for 20min immediately after administration of 123I-BMIPP (dynamic study). Early and delayed myocardial single photon emission computed tomography (SPECT) images were expressed as Bull's eyes and the myocardium was divided into four segments to calculate the washout rate for each segment on early and late SPECT images (early and late SPECT study). No significant differences in autonomic nervous function were observed between the two groups in heart rate variability. In a dynamic study, the reduction rate from the time activity curve was significantly higher in the IFN group compared with the H group (reduction rate, IFN group, 5.3 +/- 3.7% vs H group, 1.2 +/- 3.3%; P < 0.05). In the early and delayed myocardial SPECT study, the washout rate for the IFN group was significantly increased in all myocardial areas compared to that in the H group. However, the metabolic disorder of fatty acids caused by IFN was reversed on the second 123I-BMIPP myocardial scintigraphy examination several months after IFN therapy. These results indicate that metabolic disorders of fatty acids caused by IFN therapy can be detected before abnormalities are observed by Holter-ECG or echocardiography.

Antiviral Agents↗
PubMed2000

Evaluation of autonomic nervous function during upper gastrointestinal endoscopy using heart rate variability.

To investigate autonomic nervous function during upper gastrointestinal endoscopy, we analyzed R-R interval variability from electrocardiograms obtained during endoscopy. Holter electrocardiogram recordings were made before and after premedication, and during endoscopy. Time- and frequency-domain analyses of heart rate variability were performed in 54 subjects premedicated with scopolamine butylbromide (SB group) and in 66 subjects premedicated with glucagon (G group). To determine the effect of autonomic imbalance on arrhythmia generation during endoscopy, subjects with arrhythmias (A group) were compared with subjects without arrhythmias (N group). In the SB group, high frequency spectral power (HF power; 0.15 to 0.40 Hz), which reflects parasympathetic activity, decreased significantly after premedication, and decreased further during endoscopy (P < 0.01). Moreover, HF power before premedication or during endoscopy in the A group was significantly lower than that in the N group (P < 0.01). This study suggests that the measurement of HF power prior to endoscopy can identify subjects with reduced HF power. This should allow the prevention of cardiovascular complications related to premedication and endoscope insertion.

Adult↗
PubMed2000

Stress and coping behavior in patients with diabetes mellitus.

Diabetes mellitus is a disease which must be controlled over the lifetime of a patient. We investigated the issues of stress and coping for diabetes mellitus which may influence self-management. In addition, we examined the association of these factors with blood glucose control, in order to review self-management instructions for diabetes mellitus. The study included 153 patients with diabetes mellitus. The patients were divided into two subgroups: good-control group, comprising patients with glycohemoglobin (HbA1c) values less than 7.0%; and poor-control group, comprising those with HbA1c values of 7.0% or more. All patients responded to a questionnaire regarding stress tolerance, Jalowiec and Power's coping scale and awareness of diabetes mellitus. Stress tolerance was not significantly different between the good-control and poor-control groups. No significant gender differences in coping score were evident for the good-control group. However, in the poor-control group, the coping score in men was significant higher than that in women. The problem-oriented coping score for men in the poor-control group was significantly higher than that for the good-control group (p < 0.01). In a comparison of awareness of diabetes mellitus, the proportion of patients who replied that they were rigidly following diabetes treatment was higher in the poor-control group than the good-control group. Patients with diabetes mellitus may have a knowledge of the disease and a strong will to resolve problems. This is especially true for male patients in that their will appeared to be stronger, but they may not have the resolve to establish appropriate behavior patterns. In the future, methods for evaluating self-management should be included in diabetes education.

Adaptation, Psychological↗
PubMed2000

Age-related changes in the magnitude of ventricular depolarization vector: analyses by magnetocardiogram.

The magnetocardiogram has the beneficial feature that permits the strength and location of the current dipole to be estimated. This study examines the issue of whether the magnitude of the heart current during depolarization phase was influenced by the age of healthy subjects. The magnetocardiograms were recorded by means of a second-derivative SQUID (superconducting quantum interference device) magnetometer (BT Corp, Model BMP, San Diego, CA) in 150 healthy subjects. The subjects were subgrouped into 5 age-based categories according to the age. The current dipole of the maximum QRS complex was determined from isofield contour maps during the ventricular depolarization phase, and no significant differences were observed in the magnitude in the current source for any age category. However, the amplitudes of the RV5 and SV1 + RV5 in the standard electrocardiogram were larger in 65 to 74-year-old women than other age groups, and the SV1 + RV5 was smaller for the 45 to 74-year-old men than for the men aged 25 to 44 years. These findings suggest that the age-associated changes in the QRS complex observed by the electrocardiogram are caused by increased electric resistance and not by the heart current itself. The results additionally suggest that no effects of aging were observed in the actual heart current of the heart during the depolarization phase.

Action Potentials↗
PubMed2000

Production of nitric oxide from endothelial cells by 31-amino-acid-length endothelin-1, a novel vasoconstrictive product by human chymase.

Human chymase selectively converts big endothelin (ET)-1 to 31-amino-acid-length ET-1 [ET-1(1-31)]. In this study we examined effect of ET-1(1-31) on endothelial function. ET-1(1-31) evoked contraction in a concentration-dependent manner at > 10(-8) M, which was about 10 times weaker than that of conventional ET-1 [ET-1(1-21)]. BQ485, an ETA receptor antagonist, completely abolished ET-1(1-31)-induced contraction, but BQ788, an ETB receptor antagonist, slightly enhanced it, suggesting that ET-1(1-31) relaxes artery via endothelium. On endothelial cells, ET-1(1-21) and ET-1(1-31) increased [Ca2+]i and produced NO, both of which were significantly inhibited by BQ788 and not by BQ485. These results indicate that ET-1(1-31) increased [Ca2+]i and produced NO in endothelial cells through ETB receptor similarly with ET-1(1-21), although slight difference in effect on smooth muscle cells.

Animals↗
PubMed2000

Effect of the lipoprotein lipase activator NO-1886 on adriamycin-induced nephrotic syndrome in rats.

Hyperlipidemia associated with nephrotic syndrome may play a role in the deterioration of renal function. Tsutsumi et al have previously reported that the novel compound NO-1886 increases lipoprotein lipase (LPL) activity, resulting in a reduction of plasma triglycerides and an elevation of high-density lipoprotein (HDL) cholesterol in normal rats. The aim of this study was to ascertain whether NO-1886 suppresses the renal injury by treatment of the hyperlipidemia in an Adriamycin (Kyowa Hakko Kogyo, Tokyo, Japan) induced nephrosis rat model fed a high-protein diet that induced renal dysfunction and tubulointerstitial injury. Administration of Adriamycin caused hyperlipidemia, proteinuria, and edema with ascites in rats in 4 weeks. Furthermore, a combination of Adriamycin and a high-protein diet increased plasma creatinine and blood urea nitrogen (BUN) and decreased plasma albumin. Histologically, in Adriamycin-treated rats, marked interstitial cellular infiltration, tubular lumen dilation, and tubular cast formation in the kidney were observed. NO-1886 decreased plasma triglyceride and increased HDL cholesterol in Adriamycin-induced nephrotic rats. NO-1886 treatment reduced plasma creatinine and BUN levels and increased plasma albumin in Adriamycin-treated rats; it also ameliorated the ascites and proteinuria. Histologically, NO-1886-treated rats showed a quantitatively significant preservation of tubulointerstitial lesions. These data suggest that NO-1886 may have a protective effect against Adriamycin-induced nephrosis with tubulointerstitial nephritis in rats by a modification of the plasma lipid disorder.

Animals↗