[Studies of the integration and expression of exogenes in transgenic rice obtained via particle bombardment transformation]

Various integration events from simple to complex have been found in transgenic elite rice varieties, which were co-transformed with bar and cecropin B gene by particle bombardment after system studies of the structure and expression of the transgene. It was displayed that there were one to seven insertion loci and one to ten copies of transgene in different transformants. No absolute correlation was found between the numbers of transgene copies and the gene expression. Different level expression of transgenes with similar insertion mode was also discovered. The expression cassette integrity and transcription frequency of selectable bar gene were more than non-selectable cecropin B gene, whereas gene silence in plants integrated with intact bar gene was found and higher expression level of cecropin B gene with 0.6 kb fragments degraded in terminator was deduced.

The relation between tendency for psychopathology and reduced frontal brain volume in healthy people

OBJECTIVE

We hypothesized that tendency toward psychopathology is associated with lower frontotemporal volumes.

BACKGROUND

Although there is considerable evidence for structural abnormalities in patients with major psychiatric disorders and increased recognition that neural substrates may underlie individual differences in personality, there have been no studies in healthy people attempting to relate personality to volumetric measures of brain structure.

METHOD

We used magnetic resonance imaging with an advanced method for automated segmentation of cranial compartments to gray matter, white matter, and cerebrospinal fluid. We examined the relation between frontal and temporal lobe volumes and Minnesota Multiphasic Personality Inventory measures of tendency toward psychopathology in 59 healthy individuals.

RESULTS

As hypothesized, higher scores on the clinical scales were associated with lower average frontal lobe volume. When the sample was divided according to sex, however, these correlations were significant in men (n = 29) but not in women (n = 30). The highest correlation was observed between lower frontal white matter volume in men and high schizophrenia scale score (r[27] = -0.59, p <0.001).

CONCLUSIONS

The findings suggest that personality dimensions in healthy people can be linked to neural substrates, which can potentially serve as endophenotypic markers of disposition to psychopathology. The sexually dimorphic effects are consistent with gender-related differences in the clinical manifestations of psychiatric disorders and may suggest sex hormone modulation of the psychopathologic processes.

An image-processing system for qualitative and quantitative volumetric analysis of brain images

In this work, we developed, implemented, and validated an image-processing system for qualitative and quantitative volumetric analysis of brain images. This system allows the visualization and quantitation of global and regional brain volumes. Global volumes were obtained via an automated adaptive Bayesian segmentation technique that labels the brain into white matter, gray matter, and cerebrospinal fluid. Absolute volumetric errors for these compartments ranged between 1 and 3% as indicated by phantom studies. Quantitation of regional brain volumes was performed through normalization and tessellation of segmented brain images into the Talairach space with a 3D elastic warping model. Retest reliability of regional volumes measured in Talairach space indicated errors of < 1.5% for the frontal, parietal, temporal, and occipital brain regions. Additional regional analysis was performed with an automated hybrid method combining a region-of-interest approach and voxel-based analysis, named Regional Analysis of Volumes Examined in Normalized Space (RAVENS). RAVENS analysis for several subcortical structures showed good agreement with operator-defined volumes. This system has sufficient accuracy for longitudinal imaging data and is currently being used in the analysis of neuroimaging data of the Baltimore Longitudinal Study of Aging.