Decreased occipital GABA concentrations in patients with first-episode major depressive disorder: a magnetic resonance spectroscopy study / 生物医学工程学杂志

Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the human brain. Alterations in GABAergic function are associated with a variety of neurological and psychiatric disorders. However, noninvasive in vivo measurement of GABA is difficult because of its low concentration and the presence of overlapping resonances. To study GABA concentration in the occipital cortex in major depressive disorder (MDD), a group of medication-naive, first episode depressed patients (n = 18, HAMD > 17), and a group of healthy controls (n = 23) were investigated using a Point Resolved Spectroscopy (MEGA-PRESS) on a 3.0 T MR scanner. The results showed that occipital GABA levels were significantly lower (P < 0.001) in the patient group than those in the healthy controls, yet the correlations between the severity of MDD (HAMD, BDI) and the GABA concentration is insignificant. Therefore, our data suggest that patients with first episode, unmedicated MDD have changes in cortical concentrations of GABA. This biochemical abnormality may be a marker of a trait vulnerability to mood disorder, and may explain the visual problem of severe MDD patients.

An optimized voxel-based morphometry study of gray matter abnormalities in patients with obsessive-compulsive disorder / 中华放射学杂志

Objective To explore changes of gray matter volume in patients with obsessivecompulsive disorder (OCD) in Chinese Han population using optimized voxel-based morphometry (VBM) ,and investigate its relationship with clinical symptoms. Methods Twenty patients with OCD and 20 age,sex and handedness matched healthy controls were scanned using 3D-T1 images on a 3.0 T MR system. The high resolution T1WI was preprocessed according to the optimized VBM protocol in Statistical Parametric Mapping (SPM5). Two-sample t test was performed to characterize the differences of the gray matter volume (GMV) between the OCD patients and healthy controls, and the correlations between the GMV and symptom severity and cumulative illness duration were examined using Pearson correlation in SPSS 16. 0, respectively.Results Compared to controls, OCD patients demonstrated increased GMV in left thalamus, right thalamus and left cerebellum after false discovery rate (FDR) correction. No areas of significantly decreased GMV was observed in OCD patients in relative to healthy controls. The mean eigenvalue ranged from 0. 5782 to 0. 889 representing the left thalamus volume of OCD patients was 0. 6813 ± 0. 0718, and that ranged from 0. 5546 to 0. 9062 was 0. 6869 ± 0. 0808 tor right thalamus. The mean eigenvalues were positively correlated in bilateral thalamus (r = 0. 94, P ＜ 0. 01). Conclusion Using optimized VBM, the current research indicates that the pathophysiology of OCD is associated with GMV abnormalities not only in corticostriato-thalamo-cortical (CSTC) circuit, but also in the cerebellum.

Brain functions in major depressive disorder: a resting-state functional magnetic resonance imaging study / 生物医学工程学杂志

This study sought to reveal the difference in resting-state brain functions between subjects with major depressive disorder and normal controls. Fifty-three depressed patients diagnosed with DSM-IV and 38 normal controls underwent resting-state functional magnetic resonance imaging (fMRI), and the data were analyzed using a new method called Regional Homogeneity (ReHo). Then voxel wised comparison was made to derive the resting-state brain function differences between groups. Compared with normal controls, depressed subjects showed decreased ReHo in bilateral anterior cingulate cortex (ACC), left medial frontal gyrus, and left middle temporal gyrus. Significant decreased ReHo in ACC might suggest less spontaneous neuronal activities or lower baseline brain activities of ACC in depressed subjects in comparison with normal controls.

Clinical analysis of dentinogenesis imperfecta type Ⅱ in a large Mongolian family / 基础医学与临床

Objective To figure the clinical characteristics and genetic bases of Dentinogenesis imperfecta type Ⅱ in a large Mongolian family.Methods Systematic analysis for this family was carried out using clinical detection. Results Affected individuals of Dentinogenesis imperfecta type Ⅱ were consecutively found in a five-generation family. The morbidity of the offsprings is nearly 1/2 and no sexual difference is found. The analysis of clinical features as well as dental x-ray check showed specific finding that were not found in other families. Conclusion Dentinogenesis imperfecta type Ⅱ in this Mongolian family pertains to autosomal dominant disorder with high genetic heterogeneity in clinical phenotype. Further study is warranted to identify the association of this heterogeneity with lifestyle or genetic information.