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Biomedical subjects

Satoshi Kato

Publications and source records attributed to Satoshi Kato.

At least 37 records · Page 2Linked to original sources
PubMed2005

Galanin-like peptide and ghrelin increase cytosolic Ca2+ in neurons containing growth hormone-releasing hormone in the arcuate nucleus.

Galanin-like peptide (GALP), discovered in the porcine hypothalamus, is expressed predominantly in the arcuate nucleus (ARC), a feeding-controlling center. Intracerebroventricular injection of GALP has been shown to stimulate food intake in the rats. However, the mechanisms underlying the orexigenic effect of GALP are unknown. The present study aimed to determine the target neurons of GALP in the ARC. We investigated the effects of GALP on cytosolic free Ca2+ concentration ([Ca2+]i) in the neurons isolated from the rat ARC, followed by neurochemical identification of these neurons by immunocytochemistry using antisera against growth hormone-releasing hormone (GHRH), neuropeptide Y (NPY) and proopiomelanocortin (POMC), the peptides localized in the ARC. GALP at 10(-10) M increased [Ca2+]i in 11% of single neurons of the ARC, while ghrelin, an orexigenic and GH-releasing peptide, at 10(-10) M increased [Ca2+]i in 35% of the ARC neurons. Some of these GALP- and/or ghrelin-responsive neurons were proved to contain GHRH. In contrast, NPY- and POMC-containing neurons did not respond to GALP. These results indicate that GALP directly targets GHRH neurons, but not NPY and POMC neurons, and that ghrelin directly targets GHRH neurons in the ARC. The former action may be involved in the orexigenic effect of GALP and the latter in the GH-releasing and/or orexigenic effects ghrelin.

Animals↗
PubMed2005

Cerebral activation focusing on strong tasting food: a functional magnetic resonance imaging study.

Very little research has been conducted on taste imagery because of the difficulty of doing so. We conducted a functional magnetic resonance imaging study to observe cerebral activation patterns produced in volunteers concentrating on pickled plums (umeboshi), a traditional Japanese food with a strong and sour taste. Activation was observed in the right insula, the bilateral opercula, the bilateral orbitofrontal cortices and the left Broca's area. Activation in the insula (primary gustatory area) was very weak and limited to one side. The activation pattern was similar to that of taste perception. Our results showed that it is possible for humans to imagine tastes.

Adult↗
PubMed2005

High frequency activities in the human orbitofrontal cortex in sleep-wake cycle.

We recorded human orbitofrontal electrocorticogram during wakefulness and sleep in epileptic patients using subdural electrodes. During wakefulness and rapid eye movement (REM) sleep, we observed beta activity in the raw orbitofrontal signals. Power spectral analysis demonstrated beta enhancement during wakefulness and REM sleep when compared to slow wave sleep (SWS). During the phasic REM periods, the beta power was significantly lower than during the tonic REM periods. Gamma enhancement manifested itself in four out of six subjects during the phasic periods. This study is the first that has focused on electrical activity in the human orbitofrontal cortex. Although the role of the orbitofrontal cortex during sleep still remains unclear, high frequency activities give us important suggestions in elucidating the human sleep mechanism.

Adult↗
PubMed2005

Correlation between capillary blood flow of retina estimated by SLDF and circulatory parameters of retrobulbar blood vessels estimated by CDI in diabetic patients.

BACKGROUND: The aim of this study was to investigate the correlation between the recordings of scanning laser Doppler flowmetry (SLDF) of the retina and the recordings of color Doppler imaging (CDI) of the retrobulbar circulatory parameters in diabetic patients without diabetic retinopathy. METHODS: Twenty-three diabetic patients without diabetic retinopathy were evaluated using SLDF for the apparent retinal circulation and using CDI for the apparent retrobulbar circulation in the central retinal artery, the central retinal vein and the short posterior ciliary artery. The circulatory parameters estimated in the retinal tissue using SLDF were velocity, volume and flow. The Circulatory parameters that were recorded using the CDI method were peak systolic velocity (PSV), end-diastolic velocity (EDV), mean velocity (MV), pulsatility (PI) and resistivity index (RI). We obtained the correlation coefficients between parameters of SLDF and CDI. Multiple regression analysis was performed with "flow" parameter of SLDF recordings as a dependent variable and all estimated CDI parameters as independent variables. Multiple linear regression was also performed, including the "flow" parameter of SLDF recordings as a dependent variable and PI of the CDI parameters of all the measured blood vessels as independent variables. RESULTS: The "velocity" parameter of SLDF was significantly correlated with the PI in the central retinal artery (P=0.02), PI and RI in the central retinal vein (P=0.01; P=0.01) and the PSV, MV, PI and RI in the short posterior ciliary artery, as recorded by CDI (P=0.003; P=0.02; P=0.002; P=0.01). The "volume" parameter of SLDF was significantly correlated with the PI and RI in the central retinal vein (P=0.03; P=0.03) and the PSV in the short posterior ciliary artery (P=0.03), as recorded by CDI. The "flow" parameter of SLDF was significantly correlated with the PI and RI in the central retinal vein (P=0.01; P=0.01) and the PSV, MV, PI and RI in the short posterior ciliary artery (P=0.003; P=0.03; P=0.002; P=0.01) as measured by CDI. The multiple regression analysis was statistically non-significant (P=0.86). The multiple linear regression analysis indicated that from among the PI of the evaluated blood vessels, the PI of the short posterior ciliary artery was the most significant predictor of the "flow" parameter of SLDF (P=0.01). CONCLUSION: This study suggests a positive correlation between the recordings of SLDF of the retinal tissue and the retrobulbar circulatory parameters of the CDI in diabetic patients without diabetic retinopathy.

Blood Flow Velocity↗
PubMed2005

Immunohistologic study of interleukin-1, transforming growth factor-beta, and alpha-smooth muscle actin in lens epithelial cells in diabetic eyes.

PURPOSE: To assess the effects of the cytokines interleukin-1 (IL-1), transforming growth factor-beta (TGF-beta), and alpha-smooth muscle actin (alpha-SMA) in lens epithelial cells (LECs) in normal and diabetic eyes. SETTING: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan. METHODS: Ten eyes of 10 patients with diabetic mellitus and 20 normal eyes of 20 patients with senile cataract were studied. The anterior lens capsules with LECs obtained by capsulotomy during cataract surgery were cultured. The LECs obtained immediately after surgery and on the third day of culture were immunohistologically studied to assess the activities of the cytokines. RESULTS: Interleukin-1 and TGF-beta staining showed a low level activity in some LECs in diabetic eyes but only a minimum level of activity in those in normal eyes. During culture, LECs in diabetic eyes became small and transformed into fusiform and fibroblast-like cells, and these cells were strongly stained for IL-1 and TGF-beta. Normal eyes showed little changes in cell morphology and were weakly stained for IL-1 and TGF-beta. Both with culture and with no culture, alpha-SMA showed only minimal activity in both diabetic and normal eyes, with no difference. CONCLUSION: Lens epithelial cells after cataract surgery had low IL-1 and TGF-beta activities, and these activities increased during culture. Diabetic eyes showed higher cytokine activities and more marked morphologic changes than normal eyes, suggesting that increased proliferative activity and increased cytokine activity of LECs contribute to strong anterior capsule contraction in diabetic eyes.

Actins↗
PubMed2005

[Retrospective analysis on efficacy and toxicity of 5-fluorouracil (5-FU) and l-leucovorin (l-LV) in advanced or recurrent colorectal cancer].

The aim of this study was to evaluate the efficacy and toxicity of 5-fluorouracil (5-FU) and l-leucovorin (I-LV) in 50 patients with advanced or recurrent colorectal cancer in our institute. The dose of 5-FU was 600 mg/m2 and the dose of l-LV was 250 mg/m2. Objective response were 36.8% of patients who had administration of full-dose and 14.8% of patients who had the administration of reduced dose or prolonged interval. No significant difference was observed in clinical benefit rates between patients administrated in full-dose and patients in reduced dose or prolonged interval. Median survival time (MST) of patients in reduced dose or prolonged interval is longer than patients in full-dose. These data suggest that 5-FU/l-LV can be given in the outpatient and yields improved prognosis and minimal adverse reactions even in patients in reduced dose or prolonged interval.

Adult↗
PubMed2005

[Detectability of lesions in multiplanar reformation (MPR) of the lung].

PURPOSE: To evaluate the diagnostic ability of multiplanar reformation (MPR) images of the lung in comparison with thin-section source CT images. MATERIALS AND METHODS: MPR images were reconstructed for 79 patients with suspected pulmonary disease. Slice thicknesses of source images were 2 mm in 24, 1 mm in 30, and 0.5 mm in 25 cases. The presence of centrilobular nodules, emphysema, bronchiectasis, ground-glass opacity (GGO), consolidation, interstitial thickening, and pulmonary nodule was evaluated on thin-section source images by an experienced chest radiologist to establish gold standards and then subsequently assessed on the MPR images independently by two radiologists. The sensitivity, specificity, and accuracy of each finding were calculated regarding the results of thin-section source images as the gold standards. Accuracy for the detection of findings was also statistically compared among the three groups of different source slice thicknesses using Fisher's exact test. RESULTS: Accuracy for the detection of findings was significantly less (p < 0.05) in 2 mm slice MPR for centrilobular nodule, GGO, and interstitial thickening than in 1 mm or 0.5 mm slice MPR. No statistically significant difference was observed for any of the findings between 0.5 mm and 1 mm slice MPR. Rates of sensitivity, specificity, and accuracy of the MPR images for detection of the findings were 89-100%, 73-95%, and 84-95%, respectively. CONCLUSION: In comparison with thin-section source images, MPR images are comparably sensitive but not as specific for the detection of findings. When producing MPR images, the slice thickness of source images should be less than 2 mm.

Humans↗
PubMed2005

[Remarkably low blood pressure induced by combination of SSRI and a small dose of TCA].

Recently, selective serotonin reuptake inhibitors (SSRI) have been frequently used as the first choice of antidepressants because of their safety in comparison with tricyclic antidepressive agents (TCA). On the other hand, when SSRIs are not effective, they are frequently replaced with another antidepressant. In that case, a small dose of a TCA is often added without cross tapering. We report two elderly patients with depression who exhibited markedly low blood pressure when a small dose of a TCA was added to a SSRI. The combination of a SSRI and a TCA can be hazardous because it can cause unexpected adverse effects especially in elderly patients.

Aged↗
PubMed2004

A novel germline mutation of the LKB1 gene in a patient with Peutz-Jeghers syndrome with early-onset gastric cancer.

The gene responsible for Peutz-Jeghers syndrome (PJS), LKB1 (also called STK11) was mapped to chromosome 19p13.3 and was found to encode a putative serine/threonine protein kinase, LKB1. As only a limited number (approximately 100) of germline mutations of the gene have been reported, and because the protein function is still unclear, information about LKB1 mutations and their expression should be accumulated to understand the phenotype-genotype correlation of this disease. Here we report a patient with sporadic PJS with early-onset gastric cancer. We found a novel germline frameshift mutation (757-758insT) in the LKB1 gene and a marked reduction in LKB1 protein expression in the carcinoma cells, suggesting that the loss of LKB1 function may have led to the carcinogenesis of the gastric cancer.

AMP-Activated Protein Kinase Kinases↗
PubMed2004

Limitation of Scheimpflug videophotography system in quantifying posterior capsule opacification after intraocular lens implantation.

PURPOSE: To assess the applicability of Scheimpflug videophotography system for the quantitative comparison of posterior capsule opacification after intraocular lens (IOL) implantation of different materials. DESIGN: Retrospective, nonrandomized, interventional case series. METHODS: Three groups (n = 15 eyes, each) underwent cataract surgery with implantation of acrylic, silicone, or hydrogel IOL. One year after surgery, the scatter light density at the anterior IOL surface level was measured using EAS-1000. Another three groups (n = 32 eyes, each) received acrylic, silicone, or hydrogel lens. One week after surgery, the scatter light density at the posterior capsule was measured. RESULTS: Scatter light density at the anterior IOL surface 1 year after implantation was 7.5 +/- 3.0 computer-compatible tape (CCT) steps in the acrylic group, 6.0 +/- 2.3 CCT steps in the silicone group, and 5.0 +/- 3.2 CCT steps in the hydrogel group; the density in the acrylic group was significantly greater than that in the hydrogel group (P =.026). Scatter light density at the posterior capsule level 1 week after surgery was 28.3 +/- 8.9 CCT steps in the acrylic group, 22.2 +/- 2.0 CCT steps in the silicone group, and 26.7 +/- 6.7 CCT steps in the hydrogel group; there was a significant difference between the acrylic and silicone groups (P =.0005) and between the silicone and hydrogel groups (P =.008). CONCLUSIONS: The IOL material significantly influences the scatter light density measurements of Scheimpflug videophotography system, and thus the intensity of posterior capsule opacification quantified by this system cannot be directly compared with different optic materials.

Acrylic Resins↗
PubMed2004

Relationship between anterior capsule contraction and posterior capsule opacification after cataract surgery in patients with diabetes mellitus.

PURPOSE: To prospectively assess the relationship between contraction of the anterior capsule opening and posterior capsule opacification (PCO) after cataract surgery in patients with diabetes mellitus. SETTING: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Kaiya Eye Clinic, Hamamatsu, and Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaragi, Japan. METHODS: This study comprised 45 patients (45 eyes) with diabetes mellitus who had cataract surgery. In all eyes, the anterior capsule opening area and degree of PCO were determined by diaphanoscopy using an anterior eye segment analysis system (EAS-100, Nidek, Inc.) 1 day and 1 year postoperatively. RESULTS: There was no correlation between the size of the anterior capsule opening area 1 day after surgery and the degree of PCO 1 year after surgery (Pearson correlation coefficient [r] = 0.041; P =.79). The percentage reduction in the anterior capsule opening area from 1 day to 1 year after surgery did not correlate with the degree of PCO 1 year after surgery (r = -0.08; P =.60). CONCLUSION: Contraction of the anterior capsule opening and PCO after cataract surgery cannot be explained by a common mechanism.

Aged↗
PubMed2004

Extracellular serotonin, dopamine and glutamate levels are elevated in the hypothalamus in a serotonin syndrome animal model induced by tranylcypromine and fluoxetine.

Serotonin (5-HT) syndrome is a potentially fatal condition associated with various combinations of serotonergic drugs. The present study was undertaken to demonstrate that nervous systems other than the 5-HT system also participate in the pathophysiology of 5-HT syndrome. Concentrations of 5-HT, dopamine (DA) and glutamate in the hypothalamus were measured in two different 5-HT syndrome animal models using a microdialysis technique. The first model was induced by tranylcypromine, a nonselective monoamine oxidase (MAO) inhibitor (3.5 mg/kg) and fluoxetine, a selective serotonin reuptake inhibitor (SSRI) (10 mg/kg). The second model was induced by clorgyline, an MAO-A inhibitor (1.2 mg/kg) and 5-hydroxy-L-tryptophan, a precursor of 5-HT (5-HTP) (80 mg/kg). In the first model, the levels of 5-HT and DA increased by 40-fold and 44-fold, respectively, compared with the preadministration levels. In the second model, the concentrations of 5-HT increased by up to 140-fold, whereas DA levels increased by only 10-fold, of the preadministration levels. Although the level of glutamate in the second model barely changed, a delayed increase in the glutamate level was observed in the first model. These findings suggest that not only hyperactivity of the 5-HT system, but also hyperactivity of the DA system, are present in 5-HT syndrome, and that the glutamatergic system is influenced in some 5-HT syndrome cases in which the DA concentration markedly increases.

Animals↗
PubMed2004

Migration of lens epithelial cells through haptic root of single-piece acrylic-foldable intraocular lens.

PURPOSE: To report a case of posterior capsule opacification after cataract surgery due to lens epithelial cell migration through the haptic root of a single-piece acrylic-foldable intraocular lens. DESIGN: Interventional case report. METHODS: A 60-year-old man with senile cataract underwent phacoemulsification and implantation of single-piece acrylic intraocular lens having thick and wide haptic loops. RESULTS: There were no operative or short-term postoperative complications, and patient's visual acuity was 20/20 on the day following surgery. At 19 months postoperatively, we observed posterior capsule opacity extending from the base of the intraocular lens loops. CONCLUSION: Broad and thick haptic root can be a path through which lens epithelial cells migrate toward the center of the posterior capsule, forming posterior capsule opacification.

Acrylic Resins↗
PubMed2004

Corneal epithelial barrier function in diabetic patients.

PURPOSE: To evaluate the corneal epithelial barrier function in diabetic patients. METHODS: In 29 eyes of 29 diabetic patients and 55 eyes of 55 nondiabetic controls, corneal epithelial permeability to fluorescein was measured using an anterior fluorophotometer. The average fluorescein concentration in the central cornea was compared between diabetic patients and controls. Multiple regression analysis was used to assess the factors that affect corneal epithelial barrier function in diabetic patients. RESULTS: The average fluorescein concentrations in diabetic patients and nondiabetic controls were 44.1 +/- 25.3 ng/mL and 29.9 +/- 19.8 ng/mL (mean +/- SD), respectively (P = 0.0057, unpaired t test). An explanatory variable relevant to the impaired corneal epithelial barrier function was the serum hemoglobin A1c (HbA1c) concentration (standardized partial regression coefficient = 0.466, P = 0.0163). CONCLUSIONS: The corneal epithelial barrier function is impaired in diabetic patients. Diabetic patients with higher serum HbA1c levels are more predisposed to impaired barrier function in the corneal epithelium.

Aged↗
PubMed2004

Electroencephalogram-triggered functional magnetic resonance imaging in focal epilepsy.

The high spatial resolution and cost performance of functional magnetic resonance imaging (fMRI) is useful for estimating focus localization in epilepsy, but this is difficult in the case of ictal fMRI because this is susceptible to motion artifacts. Electroencephalogram (EEG)-triggered fMRI, which is interictal, can be performed without marked movement and is thought to be useful, but requires further investigation in order to establish a methodology. The authors studied EEG-triggered fMRI in partial epileptic patients. Six patients were examined using a Nihon Kohden digital EEG recorder and Signa Horizon High Speed LX 1.5 T MRI scanner. Six electrodes were attached in the vicinity of the focus detected by scalp EEG. The fMRI scans were recorded after the discharges (activation) and scans without spikes (baseline). Equal numbers of activation and baseline scans were collected and analyzed using SPM99. In three of the six patients, an activated area was observed near the focus, but no activated areas were found in the other three subjects who tended to have a low number of spikes and low spike amplitude. Although various approaches focusing on improvement of the activation/non-activation ratio are required, EEG-triggered fMRI is a promising technique for detecting focal epileptic brain activity.

Adolescent↗
PubMed2004

Psychopathology and outcome of first-admission schizophrenic patients: hypochondriac-cenestopathic symptoms as predictors of an unfavorable outcome.

The outcome of first-admission schizophrenic patients at Jichi Medical School Hospital was investigated to identify outcome predictors of schizophrenia among the symptoms at the time of the first hospitalization. The subjects were 62 schizophrenic patients, 29 females and 33 males, consecutively discharged from the Department of Psychiatry, Jichi Medical School Hospital, between June 1983 and May 1988. The mean interval between first admission and follow-up was 13 years. Eguma's Social Adjustment Scale was used to measure social outcome. The subjects were divided into two groups according to their rating on Eguma's Scale; a favorable outcome group and an unfavorable outcome group. Information on premorbid status and psychopathology at the time of the first hospitalization was obtained from clinical records and analyzed by comparing them between the two groups. Of the 62 patients, 56 were followed-up. Nine of the 56 patients followed-up had died. While 47 patients were alive; 39 were receiving psychiatric treatment and eight were not. The 47 patients who were still living were divided into two groups; a favorable outcome group (n = 22), and an unfavorable outcome group (n = 25). No significant differences in premorbid status were found. Comparison of psychopathology at the time of the first hospitalization between the outcome groups revealed significant differences in lack of spontaneity and hypochondriac-cenestopathic symptoms. Lack of spontaneity may reflect negative symptomatology, while hypochondriac-cenestopathic symptoms may reflect a serious disturbance of ego function. There is a strong possibility that evaluation of body-related symptoms in schizophrenia will be helpful in predicting outcome.

Activities of Daily Living↗