Fetal Gyrification in Cynomolgus Monkeys: A Concept of Developmental Stages of Gyrification

Our article summarizes a series of studies about fetal gyrification and its relation to cerebral growth in cynomolgus monkeys. Based on the cerebral growth (i.e., brain weight, cerebral volume, and frontooccipital length of the cerebral hemisphere) and the developmental pattern of gyrification in each sulcus of cynomolgus monkeys, we divided the gyrification process into four stages: Stage 1. Demarcation of cerebral lobes and limbic gyri; Stage 2. Demarcation of neocortical gyri; Stage 3. Emergence of secondary and tertiary sulci; and Stage 4. Growth of sulcal length and depth. Each stage of those gyrification processes was influenced by different developmental events, such as the emergence of corticocortical long‐associative fiber tracts, cortical maturations, and subcortical white‐matter development. This is the first report to systematically propose gyrification processes closely related to the order of phyologenetical development of the cerebral cortex in primates. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Amyloid β1-42 oligomer inhibits myelin sheet formation in vitro

Accumulating evidence indicates that white matter degeneration contributes to the neural disconnections that underlie Alzheimer's disease pathophysiology. Although this white matter degeneration is partly attributable to axonopathy associated with neuronal degeneration, amyloid β (Aβ) protein-mediated damage to oligodendrocytes could be another mechanism. To test this hypothesis, we studied effects of soluble Aβ in oligomeric form on survival and differentiation of cells of the oligodendroglial lineage using highly purified oligodendroglial cultures from rats at different developmental stages. Aβ oligomer at 10 μM or higher reduced survival of mature oligodendrocytes, whereas oligodendroglial progenitor cells (OPCs) were relatively resistant to the Aβ oligomer-mediated cytotoxicity. Further study revealed that Aβ oligomer even at 1 μM accelerated 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) formazan exocytosis in mature oligodendrocytes, and, more significantly, inhibited myelin sheet formation after induction of in vitro differentiation of OPCs. These results imply a novel pathogenetic mechanism underlying Aβ oligomer-mediated white matter degeneration, which could impair myelin maintenance and remyelination by adult OPCs, resulting in accumulating damage to myelinating axons thereby contributing to neural disconnections.     

Quantitative assessment of central nervous system disorder induced by prenatal X-ray exposure using diffusion and manganese-enhanced MRI

Prenatal radiation exposure induces various central nervous system (CNS) disorders depending on the dose, affected region and gestation period. The goal of this study was to assess noninvasively a CNS development disorder induced by prenatal X-ray exposure using quantitative manganese-enhanced MRI (MEMRI) as well as apparent diffusion coefficient (ADC) and transverse relaxation time (T(2)) maps in comparison with immunohistological staining. The changes in ΔR(1) (increase in the longitudinal relaxation rate (R(1)) from before and after MnCl(2) administration.) induced by the Mn(2+) contrast agent were evaluated in the CNS of normal and prenatally irradiated rats. ADC and T(2) were also compared with the histological results obtained using hematoxylin and eosin (to estimate cell density), activated caspase-3 (apoptotic cells) and glial fibrillary acidic protein (proliferation of astrocytes/astroglia). We found the following: (i) the decreased Mn(2+) uptake (indicated by a smaller ΔR(1)) for radiation-exposed rats was predominantly correlated with a decrease in cell viability (apoptotic cytopathogenicity) and CNS cell density after prenatal radiation exposure; (ii) the longer T(2) and ADC were associated with a decrease in CNS cell density and apoptotic alteration after radiation exposure. In addition to the slight proliferation of astroglia (+58%), there was a substantial decrease in cell density (-78%) and an excessive increase in apoptotic cells (+613%) in our prenatal radiation exposure model. The results suggest that MEMRI in the prenatal X-ray exposure model predominantly reflected the decrease in cell density and viability rather than the proliferation of astroglia. In conclusion, quantitative MEMRI with ADC/T(2) mapping provides objective information for the in vivo assessment of cellular level alterations by prenatal radiation exposure, and has the potential to be used as a standard approach for the evaluation of the cellular damage of radiotherapy.     

Impact of adrenomedullin on dextran sulfate sodium-induced inflammatory colitis in mice: insights from in vitro and in vivo experimental studies

Background  

Although adrenomedullin (AM) is known to ameliorate inflammatory processes, few data exist regarding the effect of AM on inflammatory colitis. Therefore, we examined the effect of AM on inflammatory response in vitro and in vivo colitis model.     

Reduced exposure using asymmetric cone beam processing for wide area detector cardiac CT

The purpose of this study was to estimate dose reduction after implementation of asymmetrical cone beam processing using exposure differences measured in a water phantom and a small cohort of clinical coronary CTA patients. Two separate 320?×?0.5?mm detector row scans of a water phantom used identical cardiac acquisition parameters before and after software modifications from symmetric to asymmetric cone beam acquisition and processing. Exposure was measured at the phantom surface with Optically Stimulated Luminescence (OSL) dosimeters at 12 equally spaced angular locations. Mean HU and standard deviation (SD) for both approaches were compared using ROI measurements obtained at the center plus four peripheral locations in the water phantom. To assess image quality, mean HU and standard deviation (SD) for both approaches were compared using ROI measurements obtained at five points within the water phantom. Retrospective evaluation of 64 patients (37 symmetric; 27 asymmetric acquisition) included clinical data, scanning parameters, quantitative plus qualitative image assessment, and estimated radiation dose. In the water phantom, the asymmetric cone beam processing reduces exposure by approximately 20% with no change in image quality. The clinical coronary CTA patient groups had comparable demographics. The estimated dose reduction after implementation of the asymmetric approach was roughly 24% with no significant difference between the symmetric and asymmetric approach with respect to objective measures of image quality or subjective assessment using a four point scale. When compared to a symmetric approach, the decreased exposure, subsequent lower patient radiation dose, and similar image quality from asymmetric cone beam processing supports its routine clinical use.     

Crohn’s disease-specific mortality: a 30-year cohort study at a tertiary referral center in Japan

Background

In this study, survival and cause of death were investigated in patients with Crohn’s disease (CD) at a tertiary referral center.

Methods

A database was created based on the medical records of 1108 CD patients who had a history of visiting our hospital to investigate background characteristics, cumulative survival rates from diagnosis, causes of death, and the standardized mortality ratio (SMR) for each cause of death. A follow-up questionnaire survey of patients followed up inadequately was also conducted. The cumulative survival rate from diagnosis was determined using the life table method and compared with that of a sex- and age-matched population model from the year 2000.

Results

The study included 1108 patients whose mean age at diagnosis was 25.6 ± 10.8 years. The mean duration of follow-up was 14.6 ± 9.4 years, and there were 52 deaths. The cumulative survival rate was significantly lower 25 years after the diagnosis of CD (91.7%) than in the standard population model (95.7%). SMRs for both all causes [3.5; 95% confidence interval (CI): 2.7–4.6] and CD-specific causes (36.7; 95% CI 26.1–51.6) were high. Among the CD-specific causes, SMRs were especially high for small intestine and colorectal cancers, gastrointestinal diseases including intestinal failure (IF), perioperative complications, and amyloidosis.

Conclusion

The SMRs for both all causes and CD-specific causes were high in CD patients. CD-specific causes including intestinal cancer, IF, perioperative complications, and amyloidosis showed especially high SMRs.

     

Relationship between swallowing function and breathing/phonation

Objective

Clarification of the association between the swallowing function and respiratory and phonatory functions.

Evaluation of local look diffusion tensor imaging for magnetic resonance tractography of the periprostatic neurovascular bundle

The purpose of this study was to compare diffusion tensor imaging using the local look technique and sensitivity encoding for tractography of the periprostatic neurovascular bundle. We compared the surrounding tissues of the prostate in eight healthy volunteers. The results of tractography in terms of the numbers of fibers and the fractional anisotropy map were evaluated. Distortion was evaluated using the dice similarity coefficient between isotropic diffusion images created from diffusion tensor images and T2-weighted images. The number of lines in tractography was significantly greater in diffusion tensor imaging using the local look technique (p?<?0.001). Although there was no difference in image distortion of the prostate between methods, an artifact appeared in the center of the diffusion tensor image using sensitivity encoding. In conclusion, diffusion tensor imaging using the local look technique was superior to that using sensitivity encoding for tractography of the periprostatic neurovascular bundle.