Search PubMed⌕ Search

Biomedical subjects

Y Saito

Publications and source records attributed to Y Saito.

At least 19 recordsLinked to original sources
PubMed2006

Frontal cerebral blood flow change associated with infant-directed speech.

OBJECTIVE: To examine the auditory perception of maternal utterances by neonates using near-infrared spectroscopy (NIRS). METHODS: Twenty full-term, healthy neonates were included in this study. The neonates were tested in their cribs while they slept in a silent room. First, two probe holders were placed on the left and right sides of the forehead over the eyebrows using double-sided adhesive tape. The neonates were then exposed to auditory stimuli in the form of infant-directed speech (IDS) or adult-directed speech (ADS), sampled from each of the mothers, through an external auditory speaker. RESULTS: A 2 (stimulus: IDS and ADS) x 2 (recording site: channel 1 (right side) and channel 2 (left side)) analysis of variance for these relative oxygenated haemoglobin values showed that IDS (Mean = 0.25) increased brain function significantly (F = 3.51) more than ADS (Mean = -0.26). CONCLUSIONS: IDS significantly increased brain function compared with ADS. These results suggest that the emotional tone of maternal utterances could have a role in activating the brains of neonates to attend to the utterances, even while sleeping.

Acoustic Stimulation↗
PubMed2006

Identification of a novel autoantibody reactive with 155 and 140 kDa nuclear proteins in patients with dermatomyositis: an association with malignancy.

OBJECTIVE: Myositis-specific autoantibodies (MSAs) are a useful tool in diagnosis, defining clinical subsets and predicting prognosis of dermatomyositis (DM) and polymyositis (PM). In this study, we identified a novel MSA reactive with 155 and 140 kDa nuclear proteins [anti-155/140 antibody (Ab)] and determined the clinical feature of DM patients positive for this autoantibody (autoAb). METHODS: Sera from 52 Japanese patients with DM, 9 with PM, 48 with systemic lupus erythematosus (SLE), 126 with systemic sclerosis and 18 with idiopathic interstitial pneumonia were examined by immunoprecipitation assays. Positive sera were further characterized by immunodepletion and immunofluorescence staining. RESULTS: Seven of the 52 (13%) Japanese patients with DM immunoprecipitated 155 and 140 kDa proteins from 35S-labelled K562 leukaemia cell extract. No patients with SLE, systemic sclerosis or idiopathic interstitial pneumonia as well as healthy controls were positive for this autoAb. Patients with anti-155/140 Ab developed heliotrope rash, Gottron's papules or sign and flagellate erythema significantly more frequently than those negative. Notably, internal malignancy was found at significantly higher frequency in those positive than those negative (71 vs 11%; P < 0.005). In contrast, none of these patients positive for this autoAb had interstitial lung disease. CONCLUSIONS: This novel MSA is associated with cancer-associated DM and may serve as a diagnostic serological marker for this specific subset.

Adult↗
PubMed2006

Endoscopic indications for endoscopic mucosal resection of laterally spreading tumours in the colorectum.

BACKGROUND: Laterally spreading tumours (LSTs) in the colorectum are usually removed by endoscopic mucosal resection (EMR) even when large in size. LSTs with deeper submucosal (sm) invasion, however, should not be treated by EMR because of the higher risk of lymph node metastasis. AIMS: To determine which endoscopic criteria, including high magnification pit pattern analysis, are associated with sm invasion in LSTs and clarify indications for EMR. METHODS: Eight endoscopic criteria from 511 colorectal LSTs (granular type (LST-G type); non-granular type (LST-NG type)) were evaluated retrospectively for association with sm invasion, and compared with histopathological findings. RESULTS: LST-NG type had a significantly higher frequency of sm invasion than LST-G type (14% v 7%; p<0.01). Presence of a large nodule in LST-G type was associated with higher sm invasion while pit pattern (invasive pattern), sclerous wall change, and larger tumour size were significantly associated with higher sm invasion in LST-NG type. In 19 LST-G type with sm invasion, sm penetration determined histopathologically occurred under the largest nodules (84%; 16/19) and depressed areas (16%; 3/19). Deepest sm penetration in 32 LST-NG type was either under depressed areas (72%; 23/32) or lymph follicular or multifocal sm invasion (28%; 1/32 and 8/32, respectively). CONCLUSIONS: When considering the most suitable therapeutic strategy for LST-G type, we recommend endoscopic piecemeal resection with the area including the large nodule resected first. In contrast, LST-NG type should be removed en bloc because of the higher potential for malignancy and greater difficulty in diagnosing sm depth and extent of invasion compared with LST-G type.

Colonoscopy↗
PubMed2006

Oncolytic replication-competent adenovirus suppresses tumor angiogenesis through preserved E1A region.

An adenovirus (Adv) retaining normal E1A but lacking the 55 kDa E1B protein replicates preferentially in TP53-deficient cancer cells including pancreatic cancer cell lines, resulting in the oncolysis of the tumor. When tumor cells are exposed to hypoxia, hypoxia-inducible factor-1alpha (HIF-1alpha) is stabilized and activated to promote the transcription of several genes such as vascular endothelial growth factor (VEGF), but in the presence of E1A hypoxia-induced VEGF m-RNA synthesis is inhibited by E1A binding to p300. In this study, we demonstrated that the cancer cells infected with a mutant Adv in which the p300 binding site in E1A was partially deleted induced a higher expression level of VEGF as compared to those of Adv with normal E1A. An immunoprecipitation study for E1A confirmed that mutant E1A had a reduced binding capacity for p300. Although the expressions of HIF-1alpha m-RNA were almost the same in both cancer cells infected with the mutant Adv and those with the wild Adv, the amount of HIF-1alpha protein in cancer cells infected with the wild E1A Adv was lower than in those infected with the mutant E1A type Adv. In vivo, in contrast to the angiogenesis treated with mutant E1A, wild-E1A inhibited tumor angiogenesis significantly. These results suggested that E1A suppressed the production of VEGF and inhibited tumor angiogenesis by binding with p300, resulting in the inhibition of the HIF-1alpha-mediated transcription of genes through binding to HRE. This study demonstrates, for the first time, the effect of an oncolytic replication-competent Adv in inhibiting tumor angiogenesis.

Adenoviridae↗
PubMed2006

The relationships of proteinuria, serum creatinine, glomerular filtration rate with cardiovascular disease mortality in Japanese general population.

Proteinuria, high serum creatinine, and reduced glomerular filtration rate (GFR) have been associated with increased mortality from cardiovascular disease (CVD) and all causes. However, the combined effect of proteinuria with serum creatinine and GFR on CVD or all-cause mortality has not been well investigated. We conducted a 10-year prospective cohort study of 30,764 men and 60,668 women aged 40-79 years who participated in annual health checkups in 1993. The Cox proportional hazards model was used to estimate the relative risk (RR) after adjusting for age, smoking, and other cardiovascular risk factors. The multivariable RR (95% confidence interval (CI)) of CVD death for positive vs negative proteinuria was 1.38 (1.05-1.79) among men and 2.15 (1.64-2.81) among women. The respective RR for the highest vs lowest creatinine groups (> or = 1.3 vs < or = 0.8 mg/dl for men and > or = 1.1 vs < or = 0.6 mg/dl for women) was 1.56 (1.19-2.04) among men and 2.15 (1.58-2.93) among women. The respective RR for GFR < 60 vs > r = 100 ml/min/1.73 m2 was 1.65 (1.25-2.18) among men and 1.81 (1.39-2.36) among women. For individuals with proteinuria combined by hypercreatininemia or reduced GFR, the risk of CVD death was two-fold higher in men and 4-6-fold higher in women compared to those without proteinuria and with normal creatinine level or GFR. Similar associations were observed for stroke, coronary heart disease, and all-cause mortality. Proteinuria, and hypercreatininemia or reduced GFR and their combination were significant predictors of CVD and all-cause mortality.

Antihypertensive Agents↗
PubMed2006

Dysphagia-gastroesophageal reflux complex: complications due to dysfunction of solitary tract nucleus-mediated vago-vagal reflex.

We report on the complication of gastroesophageal reflux (GER) in four patients with lower brainstem dysfunction. These patients suffered from perinatal asphyxia, cerebellar hemorrhage, or congenital dysphagia of unknown origin and showed facial nerve palsy, inspiratory stridor due to vocal cord paralysis, central sleep apnea, and dysphagia, in various combinations. Naso-intestinal tube feeding was introduced in all of the patients due to recurrent vomiting and aspiration pneumonia resulting from GER. T2-weighted magnetic resonance (MR) imaging revealed symmetrical high intensity lesions in the tegmentum of the lower pons and the medulla oblongata in two of the patients, and pontomedullary atrophy in another patient. In normal subjects, lower esophageal sphincter contraction is provoked by distension of the gastric wall, through a vago-vagal reflex. Since this reflex arc involves the solitary tract nucleus, where the swallowing center is located, the association of dysphagia and GER in the present patients is thought to result from the lesions in the tegmentum of medulla oblongata. We propose the term "dysphagia-GER complex" to describe the disturbed motility of the upper digestive tract due to lower brainstem involvement. In children with brainstem lesions, neurological assessment of GER is warranted, in addition to the examination of other signs of brainstem dysfunction, including dysphagia and respiratory disturbance.

Child, Preschool↗
PubMed2006

Catalytically inactive lipoprotein lipase overexpression increases insulin sensitivity in mice.

Abnormalities in lipoprotein lipase (LPL) function contribute to the development of hypertriglyceridemia, one of the characteristic disorders observed in the metabolic syndrome. In addition to the hydrolyzing activity of triglycerides, LPL modulates various cellular functions via its binding ability to the cell surface. Here we show the effects of catalytically inactive LPL overexpression on high-fat diet (HFD)-induced decreased systemic insulin sensitivity in mice. The binding capacity of catalytically inactive G188E-LPL to C2C12 skeletal muscle cells was not significantly different from that of wild type LPL. Insulin-stimulated IRS-1 phosphorylation and glucose uptake were increased by addition of wild type or mutant LPL in C2C12 cells. After 10 weeks' of HFD feeding, mice had significantly higher blood glucose levels than chow-fed mice in insulin tolerance tests. The blood glucose levels after insulin injection was significantly decreased in mutated LPL-overexpressing mice (G188E mice), as well as in wild type LPL-overexpressing mice (WT mice). Overexpression of catalytically inactive LPL, as well as wild type LPL, improved impaired insulin sensitivity in mice. These results show that decreased expression of LPL possibly causes the insulin resistance, in addition to hypertriglyceridemia, in metabolic syndrome.

Animals↗
PubMed2006

Subcutaneous fat modulates insulin sensitivity in mice by regulating TNF-alpha expression in visceral fat.

The distribution of fat in obese persons is related to the risk of developing various metabolic disorders, such as glucose intolerance, dyslipidemia and hypertension, and the combination of these conditions is known as the metabolic syndrome. The aim of this study was to investigate the role of subcutaneous fat in regulating insulin resistance and its influence on TNF-alpha expression in visceral fat, by using mice that were subjected to subcutaneous lipectomy with or without subsequent fat transplantation. After partial subcutaneous lipectomy, mice showed significantly greater accumulation of visceral fat compared with sham-operated control mice. Lipectomy led to higher plasma insulin and lower plasma glucose levels after loading with glucose and insulin, respectively, compared with the levels in control mice. Insulin-induced phosphorylation of IRS-1 was decreased in the skeletal muscles of lipectomized mice. Subcutaneous transplantation of fat pads into lipectomized mice reversed the above-mentioned changes indicating insulin resistance in these animals. The fat storage area of adipocytes and TNF- alpha expression by adipocytes in visceral fat were significantly higher in the lipectomized mice than in controls, while subcutaneous transplantation of fat reduced both the fat storage area and TNF-alpha expression. The insulin resistance of lipectomized mice was also ameliorated by systemic neutralization of TNF-alpha activity using a specific antibody. These findings obtained in mice subjected to subcutaneous lipectomy with/without subsequent fat transplantation indicate that subcutaneous fat regulates systemic insulin sensitivity, possibly through altering fat storage and the expression of TNF-alpha by adipocytes in visceral fat. The balance between accumulation of subcutaneous fat and visceral fat may be important with respect to the occurrence of systemic insulin resistance in the metabolic syndrome.

Animals↗
PubMed2006

Genetic variations and haplotype structures of the ABCB1 gene in a Japanese population: an expanded haplotype block covering the distal promoter region, and associated ethnic differences.

As functional ABCB1 haplotypes were recently reported in the promoter region of the gene, we resequenced the ABCB1 distal promoter region, along with other regions (the enhancer and proximal promoter regions, and all 28 exons), in a total of 533 Japanese subjects. Linkage disequilibrium (LD) analysis based on 92 genetic variations revealed 4 LD blocks with the same make up as previously described (Blocks -1, 1, 2 and 3), except that Block 1 was expanded to include the distal promoter region, and that a new linkage between polymorphisms -1,789G>A in the distal promoter region and IVS5 + 123A>G in intron 5 was identified. We re-assigned Block 1 haplotypes, and added novel haplotypes to the other 3 blocks. The reported promoter haplotypes were further classified into several types according to tagging variations within Block 1 coding or intronic regions. Our current data reconfirm the haplotype profiles of the other three blocks, add more detailed information on functionally-important haplotypes in Block 1 and 2 in the Japanese population, and identified differences in haplotype profiles between ethnic groups. Our updated analysis of ABCB1 haplotype blocks will assist pharmacogenetic and disease-association studies carried out using Asian subjects.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2006

Contribution of systemic arterial compliance and systemic vascular resistance to effective arterial elastance changes during exercise in humans.

BACKGROUND: Effective arterial elastance (Ea), an index of arterial load, increases with elevations in left ventricular elastance to maximize the efficiency of left ventricular stroke work during exercise. Systemic arterial compliance (C) and vascular resistance (R) are the primary components contributing to Ea, and R plays a greater role in determining Ea at rest. We hypothesized that the contribution of C to Ea increases during exercise to maintain an optimal balance between arterial load and ventricular elastance, and that the increase in Ea is due primarily to a reduction in C. AIM: The aim of this study was to investigate the contributions of C and R to Ea during exercise. METHODS: Ea (0.9 x systolic blood pressure/stroke volume), C (stroke volume/pulse pressure), R (mean blood pressure/cardiac output), and cardiac cycle length (T) were measured at rest and during exercise of 40%, 60% and 80% maximal oxygen uptake (O(2max)) using Doppler echocardiography in 45 healthy men. RESULTS: Ea did not differ between rest and 40%O(2max), but it was greater at 60% and 80%O(2max). C markedly decreased during exercise in an exercise intensity-dependent manner. The changes in R/T during exercise were small, whereas it decreased at 40%O(2max) and gradually increased at 60% and 80%O(2max). CONCLUSIONS: The present results suggest that the contribution of systemic arterial compliance to effective arterial elastance increases during exercise. Therefore, we propose that the increase in arterial load during exercise is mainly driven by a reduction in systemic arterial compliance.

Adult↗
PubMed2006

Frontal white matter anisotropy and symptom severity of late-life depression: a magnetic resonance diffusion tensor imaging study.

OBJECTIVES: To investigate the disruption of neural circuits in the frontal lobes and limbic structures in late-life depressed patients compared with healthy controls, and to examine the correlation between the degree of microstructural abnormalities of white matter and clinical symptom severity in late-life depression. METHODS: Thirteen patients with late-life depression and matched control subjects underwent diffusion tensor imaging. Fractional anisotropy (FA), an index of the integrity of white matter tracts, was determined in the white matter of frontal, temporal, and occipital brain regions and the corpus callosum. RESULTS: A significant reduction was found in white matter FA values of widespread regions of the frontal and temporal lobes of depressed patients. Also, there was some evidence suggesting that white matter FA values of the inferior frontal brain region are inversely related to severity of depression. CONCLUSIONS: These results suggest the possible loss of integrity within frontal and temporal white matter fibre tracts and implicate the orbitofrontal circuit in symptom severity in late-life depression.

Anisotropy↗