Cortical variability and asymmetry in normal aging and Alzheimer's disease

The onset of Alzheimer's disease (AD) is accompanied by a complex and distributed pattern of neuroanatomic change, difficult to distinguish clinically from dynamic alterations in normal aging. Extreme variations in the sulcal patterns of the human cortex have made it difficult to identify diffuse and focal variations in cortical structure in neurodegenerative disease. We report the first comprehensive 3D statistical analysis of deep sulcal structure in vivo, in both normal aging and dementia. High-resolution 3D T1-weighted fast SPGR (spoiled GRASS) MRI volumes were acquired from 10 patients diagnosed with AD (NINCDS-ARDRA criteria; age: 71.9 +/- 10.7 years) and 10 normal subjects matched for age (72.9 +/- 5.6 years), gender, educational level and handedness. Scans were digitally transformed into Talairach stereotaxic space. To determine specific patterns of cortical variation in dementia patients, 3D average and probabilistic maps of primary deep sulci were developed for both normal and AD groups. Major sulci (including supracallosal, cingulate, marginal, parieto-occipital, anterior and posterior calcarine sulci, and Sylvian fissures) were modeled as complex systems of 3D surfaces using a multi-resolution parametric mesh approach. Variations and asymmetries in their extents, curvature, area and surface complexity were evaluated. Three- dimensional maps of anatomic variability, structural asymmetry and local atrophy indicated severe regionally selective fiber loss in AD. A midsagittal area loss of 24.5% at the corpus callosum's posterior midbody (P < 0.025) matched increases in structural variability in corresponding temporo-parietal projection areas. Confidence limits on 3D cortical variation, visualized in 3D, exhibited severe increases in AD from 2 to 4 mm at the callosum to a peak SD of 19.6 mm at the posterior left Sylvian fissure. Normal Sylvian fissure asymmetries (right higher than left; P < 0.0005), mapped for the first time in three dimensions, were accentuated in AD (P < 0.0002), and were greater in AD than in controls (P < 0.05). Severe AD-related increases in 3D variability and asymmetry may reflect disease-related disruption of the commissural system connecting bilateral temporal and parietal cortical zones, regions known to be at risk of early metabolic dysfunction, perfusion deficits and selective neuronal loss in AD.      

Spinal arachnoid cysts in children

Five cases of benign spinal arachnoid cysts in children are described with their clinical, neuroradiological, surgical and pathological findings. Intraspinal benign arachnoid cysts may be confidently diagnosed myelographically when there is complete or partial obstruction with multiple oily contrast/cerebrospinal fluid levels as in 3 cases in this series. The multiple fluid levels are probably produced by multiple cysts or a cyst loculated due to partial compression by arachnoid bands either related to the normal septum posticum, congenital or acquired adhesion rather than to trabeculations within the cyst. In this series, the origin of the cysts is considered to be congenital.     

原发性硬化性胆管炎的诊断:磁共振胆道成像与内镜逆行性胆道造影的比较

目的　检验磁共振胆道成像作为诊断原发性硬化性胆管炎的可选择性方法的价值。病例和方法　20例原发性硬化性胆管炎行内镜逆行性胆道造影和磁共振胆道成像。评价肝内外胆道显示率和病理性改变。结果　胆管和肝管壁不规则(6/7),所有病例均存在胆道狭长或扩张,磁共振胆道成像(ＭＲＣＰ)显示肝外胆管多段狭长和扩张较好,而ＥＲＣＰ因受图像分辨率的限制,仅可显示胆管周围分支的中断。ＭＲＣＰ显示早期原发性硬化性胆管炎的胆道系统壁不规则改变亦较ＥＲＣＰ稍好。结论　原发性硬化性胆管炎早期诊断,ＭＲＣＰ可以作为ＥＲＣＰ的补充,而就晚期原…     

Noncycling state of peripheral blood progenitor cells mobilized by granulocyte colony-stimulating factor and other cytokines

Incubation with high doses of tritiated thymidine in vitro was used to determine the percent of progenitor cells in the S phase of the cell cycle. Peripheral blood (PB), bone marrow (BM), and spleen populations from mice injected with granulocyte colony-stimulating factor (G-CSF) at 5 micrograms/day for 5 days and BM cells from uninjected littermates were assayed. Although the percentage of progenitor cells in S phase in the marrow (47% +/- 5%) and spleen (52% +/- 9%) was increased significantly in G-CSF-treated mice, only a small proportion of PB progenitor cells (PBPC) were in S phase (7% +/- 4%). In normal human subjects injected with G-CSF at 5 or 10 micrograms/kg/d, the proportions of PB myeloid (-1 +/- 4%) and erythroid (0% +/- 8%) progenitor cells in S phase were very low compared with the proportion of myeloid progenitor cells in S phase in normal BM (34% +/- 10%). Similarly, the large majority of steady-state PBPC and PBPC mobilized by interleukin-3 in combination with either granulocyte-macrophage colony-stimulating factor or G-CSF were also found not to be in S phase. Experiments indicated that the low percentages of PBPC in S phase were not ascribable either to inhibitory elements in the blood or to reduced responsiveness to growth factors.     

Effect of phototherapy on thyroid stimulatory hormone and free thyroxine levels

Objective : To study the effect of phototherapy for neonatal hyperbilirubinaemia on thyroid function as neonatal thyroid screening is sometimes performed during exposure to phototherapy. Methodology : Infants with non-haemolytic hyperbilirubinaemia were sequentially allocated to fibre-optic phototherapy, conventional daylight phototherapy, or a combination of both. Bilirubin concentration was monitored 12 hourly by capillary blood sampling; venous blood was sampled for thyroid stimulating hormone (TSH) and free thyroxine (fT₄) determinations, at start of exposure, at 24 h, end of exposure and 1 day later. Comparable unexposed infants served as controls. Results : All 123 study infants and 25 controls remained well during the study. Bilirubin levels declined during phototherapy, being most rapid in the combination group. The TSH and fT₄ values at start of exposure were 3.86 ± 0.41 mU/L (mean ± SEM) and 33.20 ± 1.16 pmol/L, respectively, in the fibre-optic group, 3.62 ± 0.38 mU/L and 37.22 ± 1.76 pmol/L in the daylight group, and 4.40 ± 0.48 mU/L and 29.91 ± 1.13 pmol/L in the combined group, compared with 5.77 ± 0.40 mU/L and 34.46 ± 1.68 pmol/L in the control group. The TSH and fT₄ values declined with increasing age in the phototherapy and control groups with end of exposure values of 2.90 ± 0.28mU/L and 27.71 ± 0.71 pmol/L, 2.77 ± 0.31 mU/L and 33.52 ± 1.22pmol/L, and 3.44 ± 0.30 mU/L and 27.54 ± 0.88 pmol/L, respectively, compared with 4.21 ± 0.61 mU/L and 27.19 ± 2.33 pmol/L (at 72 h) in the control group. The pattern of TSH and fT₄ decline in the exposed and control groups was similar, being related to increasing age. Conclusions : The validity of neonatal thyroid screening is not affected by fibre-optic or conventional phototherapy or by both combined.