Tsuyoshi Shimomura

Clinical features of symptomatic Rathke's cleft cyst

To investigate the clinical features of Rathkes cleft cysts (RCCs), we retrospectively analyzed 15 cases with histologically confirmed RCCs. All patients underwent formal testing of visual field, endocrinological evaluation and magnetic resonance imagings. As overall presenting symptoms, endocrine disturbance was the most common symptoms, followed by visual disturbance and headache. Among the endocrine disturbances based on adenohypophysial dysfunction, hyperprolactinemia was most common. Considering the size of RCCs, RCCs could induce hyperprolactinemia only when the cysts became large enough to compress the infundibular system. Our series showed relative high incidence of pituitary dwarfism and diabetes insipidus (DI). These facts indicated that RCCs could evoke hyposecretion of growth hormone in young patients and DI in aged patients by direct compression of the pituitary gland in the early stage of progression. All cases who had headache had no other symptoms. We could not prove the evidence that RCCs could induce headaches in these cases. This might be suggested that headache could not be a sole symptom in cases of RCCs.

Comparison of Multiple Parameters Obtained on 3T Pulsed Arterial Spin-Labeling, Diffusion Tensor Imaging, and MRS and the Ki-67 Labeling Index in Evaluating Glioma Grading

BACKGROUND AND PURPOSE: Pulsed arterial spin-labeling, DTI, and MR spectroscopy provide useful data for tumor evaluation. We evaluated multiple parameters by using these pulse sequences and the Ki-67 labeling index in newly diagnosed supratentorial gliomas. MATERIALS AND METHODS: All 32 patients, with grade II (3 each of diffuse astrocytoma, oligodendroglioma, and oligoastrocytoma), grade III (3 anaplastic astrocytomas, 4 anaplastic oligodendrogliomas, and 1 anaplastic oligoastrocytoma), and grade IV (14 glioblastomas and 1 glioblastoma with an oligodendroglioma component) cases underwent pulsed arterial spin-labeling, DTI, and MR spectroscopy studies by using 3T MR imaging. The following variables were used to compare the tumors: relative cerebral blood flow, fractional anisotropy; ADC tumor/normal ratios; and the Cho/Cr, NAA/Cho, NAA/Cr, and lactate/Cr ratios. A logistic regression and receiver operating characteristic analysis were used to assess parameters with a high sensitivity and specificity to identify the threshold values for separate grading. We compared the Ki-67 index with various MR imaging parameters in tumor specimens. RESULTS: Significant correlations were observed between the Ki-67 index and the mean, maximum, and minimum ADC, Cho/Cr, and lactate/Cr ratios. The receiver operating characteristic analysis showed that the combination of the minimum ADC and Cho/Cr ratios could differentiate low-grade and high-grade gliomas, with a sensitivity and specificity of 87.0% and 88.9%, respectively. The mean and maximum relative cerebral blood flow ratios were used to classify glioblastomas from other-grade astrocytomas, with a sensitivity and specificity of 92.9% and 83.3%, respectively. CONCLUSIONS: Our findings indicate that pulsed arterial spin-labeling, DTI, and MR spectroscopy are useful for predicting glioma grade. Additionally, the parameters obtained on DTI and MR spectroscopy closely correlated with the proliferative potential of gliomas.

Association between hippocampal volume and serum adiponectin in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (DM) is associated with cognitive dysfunction and hippocampus volume. The aim of the present study was to test the hypothesis that the level of the adipocytokine adiponectin correlates with hippocampus volume and insulin resistance in patients with type 2 DM. A total of 45 patients with type 2 DM were divided into two groups: a low adiponectin group and a normal adiponectin group. Hippocampus volume was measured by computer-assisted analysis using a magnetic resonance imaging (MRI) voxel-based specific regional analysis system developed for the study of Alzheimers disease as the end point for assessment of hippocampus volume. Mean hippocampus volume was lower in the low adiponectin group than in the normal adiponectin group (P<.0001). Fasting serum concentrations of glucose (P<.05) and insulin (P<.0001), and homeostasis model assessment index (P<.0001), were all higher in the low adiponectin group than in the normal adiponectin group. Multiple regression analysis showed that hippocampus volume independently predicted serum adiponectin level. These results suggest that circulating levels of adiponectin are related to hippocampus volume in patients with type 2 DM.

Abdominal visceral fat accumulation is associated with hippocampus volume in non-dementia patients with type 2 diabetes mellitus

Obesity is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of visceral fat accumulation (VFA) correlates with hippocampus volume and insulin resistance in non-dementia patients with type 2 diabetes. Subjects included 48 non-dementia patients with type 2 diabetes, who were divided into two groups, high VFA group (mean+/-standard deviation: age=65+/-6 years, n=30) and normal VFA group (65+/-5 years, n=18). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging (MRI) voxel-based specific regional analysis system developed for the study of Alzheimers disease (VSRAD), which yields a Z-score as the end point for assessment of hippocampal volume. The Z-score was higher in the high VFA group than in the normal VFA group (p<0.0001). The fasting plasma glucose (p<0.05) and insulin concentrations (p<0.0001) and the homeostasis model assessment (HOMA) index (p<0.0001) were higher in the high VFA group than in the normal VFA group. Multiple regression analysis showed that VFA levels were independently predicted by Z-score and HOMA index. Our results indicate that the elevated level of VFA in Japanese non-dementia patients with type 2 diabetes is characterized by increased hippocampus volume and insulin resistance, and that the Z-score and HOMA index are independent predictors of VFA.

Visceral fat accumulation is a significant risk factor for white matter lesions in Japanese type 2 diabetic patients

Background  The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. The elevated visceral fat accumulation (VFA) has been reported to be closely related to the development of atherosclerosis. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with VFA and insulin resistance in type 2 diabetic patients not receiving insulin treatment.

High-sensitivity C-reactive protein is associated with hippocampus volume in nondementia patients with type 2 diabetes mellitus

The elevated level of high-sensitivity C-reactive protein (HSCRP) is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of HSCRP correlates with hippocampus volume and insulin resistance in nondementia patients with type 2 diabetes mellitus. Subjects included 45 nondementia patients with type 2 diabetes mellitus, who were divided into 2 groups: high-HSCRP group (age, 65 ± 6 years [mean ± SD]; n = 17) and normal-HSCRP group (65 ± 7 years, n = 28). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging voxel-based specific regional analysis system developed for the study of Alzheimer disease (VSRAD), which yields a z score as the end point for assessment of hippocampal volume. The z score was higher in the high-HSCRP group than in the normal-HSCRP group (P < .0001). The fasting plasma glucose (P < .05) and insulin concentrations (P < .0001) and the homeostasis model assessment (HOMA) index (P < .0001) were higher in the high-HSCRP group than in the normal-HSCRP group. Multiple regression analysis showed that HSCRP levels were independently predicted by z score and HOMA index. Our results indicate that the elevated level of HSCRP in Japanese nondementia patients with type 2 diabetes mellitus is characterized by increased hippocampus volume and insulin resistance, and that the z score and HOMA index are independent predictors of HSCRP.

The role of microalbuminuria and insulin resistance as significant risk factors for white matter lesions in Japanese type 2 diabetic patients

ABSTRACT Objective: The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. Microalbuminuria, which is associated with diabetes, has been flagged as a novel predictor for cerebrovascular events. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with microalbuminuria and insulin resistance in patients with type 2 diabetic mellitus (DM) not receiving insulin treatment. Patients and methods: Based on brain magnetic resonance imaging (MRI) findings, 90 type 2 diabetic patients were divided into two groups: a WML-positive group (57 ± 8 years, mean ± SD, n = 34) and a WML-negative group (57 ± 6 years, n = 56). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin (F-IRI), homeostasis model assessment (HOMA) index, and hemoglobin A 1c (HbA1c). Results: The body mass index was higher in the WML-positive group than in the WML-negative group (p < 0.01). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol (HDL-C) was lower in the WML-positive group than in the WML-negative group (p < 0.05 and p < 0.0001, respectively). Fasting plasma glucose (p < 0.005), insulin concentrations (p < 0.0001), HOMA index (p < 0.0001), and urinary albumin excretion (p < 0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the microalbuminuria and insulin resistance (p < 0.005, p < 0.0005, respectively). Conclusion: The results of this preliminary study indicate that the presence of WML was associated with the microalbuminuria and insulin resistance in these Japanese patients with type 2 DM; larger cohort studies are warranted to confirm these findings.

Hyperthymic temperament and brightness judgment in healthy subjects: Involvement of left inferior orbitofrontal cortex

BACKGROUND Hyperthymic temperament has been generally accepted as one of premorbid temperament of bipolar disorders. Since recent several studies indicate an association between illuminance and hyperthymic temperament, it can be hypothesized that more hyperthymic temperament subjects have a different threshold of brightness or darkness perception in comparison with less hyperthymic temperament subjects. METHODS We compared the threshold of brightness and darkness judgment between more and less hyperthymic subjects, and by simultaneously using fMRI we compared activations of whole brain between these subjects by two sample t-test. Furthermore, the association between the activations and hyperthymic temperament scores was analyzed. RESULTS Although there was no significant difference in the threshold of brightness or darkness judgment between more and less hyperthymic subjects, there was a significant difference in activations of the regions including left superior temporal gyrus, left inferior orbitofrontal cortex, left triangular inferior frontal gyrus and left insula between these subjects. Moreover, there was a significantly positive association between a cluster containing left inferior orbitofrontal cortex and hyperthymic temperament scores. The common activated region of these two analyses (categorical and continuous ones) was determined as left inferior orbitofrontal cortex. LIMITATIONS Limitation of the present study is a lack of brightness and darkness preference experiment between more and less hyperthymic subjects. CONCLUSIONS The present findings suggest that the threshold of brightness and darkness judgment is not different between more and less hyperthymic subjects, and that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which has been reported to be associated with bipolar disorder.

Difference in brain activations during appreciating paintings and photographic analogs

Several studies have investigated neural correlates of aesthetic appreciation for paintings but to date the findings have been heterogeneous. This heterogeneity may be attributed to previous studies’ measurement of aesthetic appreciation of not only the beauty of paintings but also the beauty of motifs of the paintings. In order to better elucidate the beauty of paintings, it seems necessary to compare aesthetic appreciation of paintings and photographic analogs which included corresponding real images. We prepared for famous painters’ pictures and their photographic analogs which were set up to resemble each painting in order to investigate the hypothesis that there exist specific neural correlates associated with the aesthetic appreciation for paintings. Forty-four subjects participated in functional magnetic resonance study which required comparisons of aesthetic appreciation of paintings of still life and landscape versus photographic analogs including corresponding real images of still life and landscape. Bilateral cuneus and the left lingual gyrus were activated in the comparison of aesthetic appreciation of paintings versus photographic analogs. In conclusion, the present findings suggest a possibility of the existence of specific neural correlates associated with the aesthetic appreciation for paintings and that bilateral cuneus and the left lingual gyrus may be involved.

Homocysteine levels are associated with hippocampus volume in type 2 diabetic patients

Eur J Clin Invest 2011; 41 (7): 751–758