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Biomedical subjects

Shinsuke Yamada

Publications and source records attributed to Shinsuke Yamada.

11 recordsLinked to original sources
PubMed2007

Central pulse wave velocity is responsible for increased brachial-ankle pulse wave velocity in subclinical hypothyroidism.

OBJECTIVE: Subclinical hypothyroidism affects 5-15% of the general population, and is associated with increased morbidity from cardiovascular disease. We recently reported a significant increase in brachial-ankle pulse wave velocity (baPWV), a parameter of arterial stiffening and an independent predictor for the presence of cardiovascular disease, in subclinical hypothyroidism. The current study was performed to assess which arterial segment is responsible for enhanced baPWV in subclinical hypothyroidism. PATIENTS AND METHODS: Central PWV (PWV in heart-femoral segments), peripheral PWV (PWV in femoral-ankle segments), and baPWV were measured in subclinical hypothyroid patients and normal subjects. RESULTS: Central PWV, baPWV, and peripheral PWV were significantly higher in subclinical hypothyroid patients than in normal subjects. BaPWV was significantly and positively correlated with central and peripheral PWV in both groups. However, a significant and positive correlation between central and peripheral PWV in normal subjects was not found in subclinical hypothyroid patients. Moreover, stepwise regression analysis showed that the association of central PWV with baPWV was stronger than that of peripheral PWV, whereas in normal subjects central PWV was not associated with baPWV. CONCLUSIONS: Our results demonstrate that central and peripheral PWV are significantly higher in subclinical hypothyroid patients, and that the increase in baPWV depends more strongly on central PWV than on peripheral PWV in these patients. This suggests that increased elastic arterial stiffening of the aorta, rather than of peripheral muscular arteries, might be more responsible for increased general arterial stiffening in subclinical hypothyroid patients.

Ankle↗
PubMed2006

Improvement in accuracy of multiple sequence alignment using novel group-to-group sequence alignment algorithm with piecewise linear gap cost.

BACKGROUND: Multiple sequence alignment (MSA) is a useful tool in bioinformatics. Although many MSA algorithms have been developed, there is still room for improvement in accuracy and speed. In the alignment of a family of protein sequences, global MSA algorithms perform better than local ones in many cases, while local ones perform better than global ones when some sequences have long insertions or deletions (indels) relative to others. Many recent leading MSA algorithms have incorporated pairwise alignment information obtained from a mixture of sources into their scoring system to improve accuracy of alignment containing long indels. RESULTS: We propose a novel group-to-group sequence alignment algorithm that uses a piecewise linear gap cost. We developed a program called PRIME, which employs our proposed algorithm to optimize the well-defined sum-of-pairs score. PRIME stands for Profile-based Randomized Iteration MEthod. We evaluated PRIME and some recent MSA programs using BAliBASE version 3.0 and PREFAB version 4.0 benchmarks. The results of benchmark tests showed that PRIME can construct accurate alignments comparable to the most accurate programs currently available, including L-INS-i of MAFFT, ProbCons, and T-Coffee. CONCLUSION: PRIME enables users to construct accurate alignments without having to employ pairwise alignment information. PRIME is available at http://prime.cbrc.jp/.

Algorithms↗
PubMed2006

Paraarticular trabecular bone loss at the ultradistal radius and increased arterial stiffening in postmenopausal patients with rheumatoid arthritis.

OBJECTIVE: We recently reported enhanced arterial thickening in patients with rheumatoid arthritis (RA) and the importance of increased bone resorption in this process. Our aim was to examine whether arterial stiffening, another aspect of atherosclerosis, is also increased in patients with RA, and to determine if it is an important risk factor. METHODS: The subjects were 47 patients with RA and 49 healthy controls, all postmenopausal women. Subjects having risk factors for atherosclerosis were excluded. Femoral-ankle (fa) pulse wave velocity (PWV) and brachial-ankle (ba) PWV were measured in all patients using a waveform analyzer. Bone mineral density (BMD) at the ultradistal radius was assessed by peripheral quantitative computed tomography. Inflammation markers (C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, platelet count) and bone resorption markers (urinary excretion of deoxypyridinoline and N-terminal telopeptide) were also measured. RESULTS: The median values of faPWV and baPWV in RA patients were 1124 cm/s [interquartile range (IQR) 1040-1175] and 1539 cm/s (IQR 1297-1738), respectively, which were significantly greater than the respective values of 982 cm/s (IQR 819-1054; p < 0.001) and 1322 cm/s (IQR 1112-1398; p = 0.004) in controls. In multiple regression analysis, the presence of RA emerged as an independent factor associated with the greater faPWV and baPWV when adjusted for age, blood pressure, and smoking. In RA patients alone, BMD in the trabecular bone component, but not for the total bone (cortical plus trabecular), at the ultradistal radius correlated significantly with both faPWV and baPWV. Multiple regression analysis showed that trabecular BMD at the distal radius was a significant factor independently associated with greater faPWV and baPWV when adjusted for age, blood pressure, and smoking. None of the measured inflammation markers or bone resorption markers correlated with either faPWV or baPWV in patients with RA. CONCLUSION: Patients with RA show increased arterial stiffening, in addition to the arterial thickening we have previously reported, supporting the notion of enhanced atherosclerosis in RA patients. Paraarticular bone loss in the trabecular bone component at the ultradistal radius is a factor significantly associated with increased arterial stiffening in RA patients.

Amino Acids↗
PubMed2006

[Age-related transformation of bone metabolism].

Bone mass reaches peak bone mass by the age of about from eighteen to twenty in men and women, since then it is reduced with aging every year. Decrease in bone mass with aging is classified postmenopausal osteoporosis and senile osteoporosis of involutional osteoporosis. Bone mass is reduced suddenly in menopausal period on postmenopausal osteoporosis, but it is reduced slowly in men and women on senile osteoporosis. We will give an outline of age-related transformation of bone metabolism classified from growth period to maturity period, menopausal period in men and women, and aging period.

Adult↗
PubMed2005

Associations between physical activity, peripheral atherosclerosis and bone status in healthy Japanese women.

The aim of this cross-sectional study was to investigate whether physical activity and bone status may affect arterial thickening and stiffening in healthy Japanese women. Healthy women (n = 149; mean age, 54 years) were recruited from those who participated in a local health check program at the Osaka City University Hospital. Physical activity was assessed by physical functioning score of SF-36, and bone status by bone mineral density (BMD) in lumbar spine and calcaneus osteo-sono index (OSI). Arterial wall thickening assessed by intima-media thickness (IMT) in common carotid artery (CA) and femoral artery (FA), and arterial wall stiffening by peak wave velocity (PWV) in heart-carotid (hc) and heart-femoral (hf) as central segment and in heart-brachial (hb) and femoral-ankle (fa) as peripheral segment, respectively. By Spearman Rank correlation, lumbar spine BMD was correlated negatively with CA IMT (rho = -0.225, p < 0.05) and FA IMT (rho = -0.215, p < 0.05), and calcaneus OSI with FA IMT (rho = -0.330, p < 0.0001) but not CA IMT (rho = -0051, p = 0.5335). Both lumbar spine BMD and calcaneus OSI correlated negatively with PWV in all segments (all p < 0.05). Physical functioning score correlated weakly but significantly in a negative manner with all PWV segments (all p < 0.05) but not IMT. Multiple regression analyses revealed a significant association of calcaneus OSI (beta = -0.240, p = 0.0039) but not lumbar spine BMD (beta = -0.067, p = 0.4541) with FA IMT, although neither lumbar spine BMD nor calcaneus OSI was associated with CA IMT. Furthermore, physical functioning score was independently associated with hb and fa PWV but not hc and hf PWV, suggesting the preferential association with peripheral segment including lower extremities. Neither lumbar spine BMD nor calcaneus OSI was associated with any segment of PWV. In conclusion, it was suggested that calcaneus OSI might be associated with arterial wall thickening preferentially in femoral artery, and that physical activity may be associated with arterial wall stiffening in peripheral segment including lower extremity but not in central segment in healthy Japanese women.

Atherosclerosis↗
PubMed2005

Increased pulse wave velocity in subclinical hypothyroidism.

OBJECTIVE: Subclinical hypothyroidism affects 5-15% of the general population and is associated with increased morbidity from cardiovascular disease. Brachial-ankle pulse wave velocity (baPWV) is a parameter of arterial stiffening and a good independent predictor for the presence of coronary artery disease. This study was performed to assess whether subclinical hypothyroidism might cause enhanced baPWV. PATIENTS AND METHODS: baPWV was examined in subclinical hypothyroid patients (n = 50) and normal control subjects (n = 50). RESULTS: Diastolic blood pressure (DBP), a main risk factor for cardiovascular disease, and baPWV were both significantly higher in subclinical hypothyroid patients than normal subjects. baPWV was significantly positively correlated with age and systolic, diastolic, and pulse pressure and significantly negatively correlated with pulse rate in both subclinical hypothyroid patients and normal subjects. In contrast, there was no significant correlation of baPWV with free T3, free T4, TSH, total, high-density lipoprotein- and low-density lipoprotein-cholesterol, and the preejection time to ejection time ratio. A comparison of individual values of baPWV and DBP and regression slopes in two groups revealed that baPWV values increase to a larger extent than the increase in DBP in subclinical hypothyroid patients. In both groups, stepwise regression analysis showed a significant and independent association of DBP with baPWV. CONCLUSIONS: The present study demonstrated significant increases of baPWV and DBP in subclinical hypothyroid patients. Furthermore, the results suggest that increased DBP might be one of the main factors responsible for increased arterial stiffening in subclinical hypothyroid patients.

Aged↗
PubMed2004

Significance of intima-media thickness in femoral artery in the determination of calcaneus osteo-sono index but not of lumbar spine bone mass in healthy Japanese people.

The aim of this cross-sectional study was to investigate whether physical activity and local arterial thickening may affect bone metabolism. To analyze the effects of physical activity and atherosclerosis on bone in healthy Japanese people, health-related quality of life (HRQL) and local arterial thickening were assessed by means of the Medical( )Outcomes Study 36-item Short Form (SF-36), and intimal-medial thickness (IMT) in common carotid artery (CA) and femoral artery (FA), respectively. Bone mineral density (BMD) in lumbar spine was measured by dual X-ray absorptiometry and the osteo-sono assessment index (OSI) of the calcaneus by ultrasound. Healthy subjects (106 male and 154 female) were recruited from those who participated in a local health check program at the Osaka City University Hospital. A significant correlation existed between lumbar spine BMD and calcaneus OSI (r=0.551, P<0.0001). Among various scores in SF-36, only physical functioning score correlated weakly but significantly in a positive manner with lumbar spine BMD (rho=0.156, P=0.0147) and calcaneus OSI (rho=0.190, P=0.0024). Lumbar spine BMD correlated negatively with FA IMT (rho=-0.191, P=0.0027) whereas calcaneus OSI with FA IMT (rho=-0.199, P=0.0014). Multiple regression analyses revealed a significant association between FA IMT and calcaneus OSI, whereas lumbar spine BMD did not correlate significantly with FA or CA IMT. When subjects were restricted to female, FA IMT, but not CA IMT, still showed tendency against independent factors negatively associated with calcaneus OSI. Furthermore, lumbar spine BMD, but not calcaneus OSI, was weakly but significantly associated with increased physical functioning score independently. In conclusion, it was suggested that physical activity may affect bone strength in lumbar spine and calcaneus and that FA IMT might be a significant determinant of bone strength in calcaneus, but not in lumbar spine, in healthy Japanese subjects.

Arteriosclerosis↗
PubMed2004

[Metabolic bone disease and bone quality].

On the progress of study concerned with pathology of metabolic bone disease such as osteoporosis, it has been known that most of bone strength can be explained by bone volume. As bone volume can be determine by bone mineral density (BMD) with dual-energy X-ray absorptiometry (DXA), it has been widely used for diagnosis of osteoporosis or efficacy of treatment. However, with the advance of bone morphometry, decrease of bone strength or existence of insufficiency fracture is influenced by not only loss of BMD but also deterioration of bone quality especially bone microstructure. In this chapter, we will give an outline of change of bone quality in metabolic bone disease.

Bone Diseases, Metabolic↗
PubMed2004

[Osteoporosis and mineral intake].

For prevention against the development of osteoporosis and related fractures, the importance of sufficient intake of calcium and vitamin D has been increasingly recognized. However, due to increasing intake of calcium, the relative intake of magnesium and trace elements, such as zinc and copper has been relatively decreasing and thus been focused in recent years. On this article, we will give an outline of the importance of magnesium and trace elements in the regulation of bone metabolism.

Bone Density↗
PubMed2003

Preferential reductions of paraarticular trabecular bone component in ultradistal radius and of calcaneus ultrasonography in early-stage rheumatoid arthritis.

Rheumatoid arthritis (RA) is a major cause of secondary osteoporosis and is frequently associated with both paraarticular and generalized osteoporosis. The present study was designed to investigate the preferential sites of reduction of bone mineral density (BMD), in the early stage of RA, with special emphasis on the differential effect of RA on BMD in trabecular and cortical components. The participants (30 RA patients and 26 healthy participants) were all female with disease duration of less than 1 year. BMD in the radius was measured at 4% (ultradistal site) and 20% (midshaft) to the ulnar length proximal to the end of radius by peripheral quantitative computed tomography. BMD in lumbar spine was measured by dual X-ray absorptiometry and the osteo-sono assessment index (OSI) of the calcaneus by ultrasound. RA patients showed lower BMD preferentially in the trabecular component, but not in cortical bone component of the ultradistal radius than age-matched normal controls. Calcaneus OSI was also significantly reduced. The radial midshaft and lumbar spine did not differ significantly between RA patients and normal controls. Trabecular BMD in the ultradistal radius exhibited negative correlations with serum CRP, ESR, and RF, and calcaneus OSI with M-HAQ score. In conclusion, it was suggested that disease activity of RA and impairment of daily physical activity might be a significant determinant of deterioration of bone structure in paraartciular distal radius and calcaneus, respectively, in early-stage RA patients.

Activities of Daily Living↗