Automated Sulcal Depth Measurement on Cortical Surface Reflecting Geometrical Properties of Sulci

Sulcal depth that is one of the quantitative measures of cerebral cortex has been widely used as an important marker for brain morphological studies. Several studies have employed Euclidean (EUD) or geodesic (GED) algorithms to measure sulcal depth, which have limitations that ignore sulcal geometry in highly convoluted regions and result in under or overestimated depth. In this study, we proposed an automated measurement for sulcal depth on cortical surface reflecting geometrical properties of sulci, which named the adaptive distance transform (ADT). We first defined the volume region of cerebrospinal fluid between the 3D convex hull and the cortical surface, and constructed local coordinates for that restricted region. Dijkstra’s algorithm was then used to compute the shortest paths from the convex hull to the vertices of the cortical surface based on the local coordinates, which may be the most proper approach for defining sulcal depth. We applied our algorithm to both a clinical dataset including patients with mild Alzheimer’s disease (AD) and 25 normal controls and a simulated dataset whose shape was similar to a single sulcus. The mean sulcal depth in the mild AD group was significantly lower than controls (p = 0.007, normal [mean±SD]: 7.29±0.23 mm, AD: 7.11±0.29) and the area under the receiver operating characteristic curve was relatively high, showing the value of 0.818. Results from clinical dataset that were consistent with former studies using EUD or GED demonstrated that ADT was sensitive to cortical atrophy. The robustness against inter-individual variability of ADT was highlighted through simulation dataset. ADT showed a low and constant normalized difference between the depth of the simulated data and the calculated depth, whereas EUD and GED had high and variable differences. We suggest that ADT is more robust than EUD or GED and might be a useful alternative algorithm for measuring sulcal depth

Aortic Dissection and Rupture in a Child

After developing sudden severe chest pain, an 11-year-old boy presented to the emergency room with chest pain and palpitations and was unable to stand up. The sudden onset of chest pain was first reported while swimming at school about 30 minutes prior to presentation. Arterial blood pressure (BP) was 150/90 mmHg, heart rate was 120/minute, and the chest pain was combined with shortness of breath and diaphoresis. During the evaluation in the emergency room, the chest pain worsened and abdominal pain developed. An aortic dissection was suspected and a chest and abdomen CT was obtained. The diagnosis of aortic dissection type B was established by CT imaging. The patient went to surgery immediately with BP control. He died prior to surgery due to aortic rupture. Here we present this rare case of aortic dissection type B with rupture, reported in an 11-year-old Korean child

Aberrant phenotypes of transgenic mice expressing dimeric human erythropoietin

<p>Abstract</p> <p>Background</p> <p>Dimeric human erythropoietin (dHuEPO) peptides are reported to exhibit significantly higher biological activity than the monomeric form of recombinant EPO. The objective of this study was to produce transgenic (tg) mice expressing dHuEPO and to investigate the characteristics of these mice.</p> <p>Methods</p> <p>A dHuEPO-expressing vector under the control of the goat beta-casein promoter, which produced a dimer of human EPO molecules linked by a 2-amino acid peptide linker (Asp-Ile), was constructed and injected into 1-cell fertilized embryos by microinjection. Mice were screened using genomic DNA samples obtained from tail biopsies. Blood samples were obtained by heart puncture using heparinized tubes, and hematologic parameters were assessed. Using the microarray analysis tool, we analyzed differences in gene expression in the spleens of tg and control mice.</p> <p>Results</p> <p>A high rate of spontaneous abortion or death of the offspring was observed in the recipients of dHuEPO embryos. We obtained 3 founder lines (#4, #11, and #47) of tg mice expressing the <it>dHuEPO </it>gene. However, only one founder line showed stable germline integration and transmission, subsequently establishing the only transgenic line (#11). We obtained 2 F1 mice and 3 F2 mice from line #11. The dHuEPO protein could not be obtained because of repeated spontaneous abortions in the tg mice. Tg mice exhibited symptoms such as short lifespan and abnormal blood composition. The red blood cell count, white blood cell count, and hematocrit levels in the tg mice were remarkably higher than those in the control mice. The spleens of the tg mice (F1 and F2 females) were 11- and -21-fold larger than those of the control mice. Microarray analysis revealed 2,672 spleen-derived candidate genes; more genes were downregulated than upregulated (849/764). Reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative real-time PCR (qRT-PCR) were used for validating the results of the microarray analysis of mRNA expression.</p> <p>Conclusions</p> <p>In conclusion, dHuEPO tg mice caused excessive erythrocytosis that led to abnormal blood composition, short lifespan, and abnormal splenomegaly. Further, we identified 2,672 genes associated with splenomegaly by microarray analysis. These results could be useful in the development of dHuEPO-producing tg animals.</p

Variability of the giant X-ray bump in GRB 121027A and possible origin

The particular giant X-ray bump of GRB 121027A triggered by \emph{Swift} is quite different from the typical X-ray flares in gamma-ray bursts. There exhibit four parts of the observed structural variabilities in the rise and decay phase of the bump. Considering the quality of four parts of the data, we can only analyze the data from about 5300 s to about 6100 s in the bump using the stepwise filter correlation method (Gao et al. 2012), and find that the $86^{+5.9}_{-9.4}~\rm s$ periodic oscillation may exist, which is confirmed by the Lomb-Scargle method (Scargle 1982). Furthermore, a jet precession model (Liu et al. 2010) is proposed to account for such a variability.Comment: 5 pages, 3 figures, accepted for publication in MNRA