New experimental model of sinus and cortical vein thrombosis in pigs for MR imaging studies

INTRODUCTION

Diagnosis of cerebral sinus vein thrombosis is still a challenge for imaging. MRI and MRA play a major role in sinus imaging. For further development of MR techniques, MR-compatible animal models are required. The aim of this study was to develop an animal model for sinus thrombosis and additional cortical vein thrombosis with a clot of human blood for MR imaging studies.

METHODS

A combined surgical and interventional approach was carried out in 13 pigs. After minimal invasive surgical access to the anterior superior sagittal sinus and cortical vein, thrombosis with human blood was induced using an interventional catheter approach. MR imaging was performed prior to and after thrombus induction.

RESULTS

Sinus thrombosis was induced in 12 of 13 animals. Three animals suffered acute subdural haemorrhage; one of these animals died during the intervention, and one died after thrombus induction. MR imaging of the thrombosed sinus could easily be performed without significant artefacts in 11 of 13 animals.

CONCLUSION

This new model of sinus and cortical vein thrombosis with a clot of human blood allows artefact-free imaging studies on MR.

SIRT2, a tubulin deacetylase, acts to block the entry to chromosome condensation in response to mitotic stress

We previously identified SIRT2, an nicotinamide adenine dinucleotide (NAD)-dependent tubulin deacetylase, as a protein downregulated in gliomas and glioma cell lines, which are characterized by aneuploidy. Other studies reported SIRT2 to be involved in mitotic progression in the normal cell cycle. We herein investigated whether SIRT2 functions in the mitotic checkpoint in response to mitotic stress caused by microtubule poisons. By monitoring chromosome condensation, the exogenously expressed SIRT2 was found to block the entry to chromosome condensation and subsequent hyperploid cell formation in glioma cell lines with a persistence of the cyclin B/cdc2 activity in response to mitotic stress. SIRT2 is thus a novel mitotic checkpoint protein that functions in the early metaphase to prevent chromosomal instability (CIN), characteristics previously reported for the CHFR protein. We further found that histone deacetylation, but not the aberrant DNA methylation of SIRT2 5'untranslated region is involved in the downregulation of SIRT2. Although SIRT2 is normally exclusively located in the cytoplasm, the rapid accumulation of SIRT2 in the nucleus was observed after treatment with a nuclear export inhibitor, leptomycin B and ionizing radiation in normal human fibroblasts, suggesting that nucleo-cytoplasmic shuttling regulates the SIRT2 function. Collectively, our results suggest that the further study of SIRT2 may thus provide new insights into the relationships among CIN, epigenetic regulation and tumorigenesis.

Prediction of gait outcome with the knee-ankle-foot orthosis with medial hip joint in patients with spinal cord injuries: a study using recursive partitioning analysis

STUDY DESIGN

Retrospective study of the degree of gait independence achieved by persons with spinal cord injury (SCI) using knee-ankle-foot orthosis with a medial single hip joint (MSH-KAFO).

OBJECTIVE

To examine the effects of the neurological level, degree of paresis, age, and inhibitory physical/other factors on the gait with a MSH-KAFO in patients with SCIs.

SETTING

Three university hospitals and two rehabilitation hospitals in Japan.

METHODS

The 45 patients (36 men, nine women) examined included 10 with injuries in the cervical cord between C6 and C8 (group C), 20 with injuries in the upper-middle thoracic cord between T4 and T10 (group UT), and 15 with injuries in the lower thoracic-lumbar cord between T12 and L1 (group TL). Mean age was 34.0 years (range 16-68 years). Of these patients, 13 used the Walkabout, four used the gear joint, and 28 used the Primewalk as the medial hip joint. Recursive partitioning, which predicted the final status of gait from the level, degree of paresis, age, and inhibitory factors, was performed, and a decision tree for gait was constructed. Inhibitory factors were spasticity, involuntary spasms or muscle contractions, pain, contracture, weakness of the upper extremities, and decreased motivation to perform gait exercise. The degree of gait independence was rated on the following five-point scale: outdoor independent gait (5 points), indoor independent gait (4 points), indoor supervised gait (3 points), indoor assisted gait (2 points), and gait within parallel bars (1 point). New branches were added to the decision tree for gait based on the clinical experience, thereby constructing a new decision tree.

RESULTS

The coincident ratio between the value predicted on the basis of the decision tree of gait and the value actually observed was 53.3%. The coincident ratio between the value predicted on the basis of the modified decision tree of gait and the actually observed value was 68.9%.

CONCLUSION

The results provide valuable information to medical teams that may assist prescription of gait orthoses.

[Technical Note: Subclavian artery misplacement of a 12F Shaldon catheter: percutaneous repair with a local closure device under temporary balloon tamponade]

A case of subsequent percutaneous repair using a local closure device with a collagen block (VasoSeal(R)) and temporary balloon tamponade after inadvertent subclavian artery misplacement of a 12F Shaldon catheter is reported. Balloon occlusion safely prevented displacement of collagen into the vascular lumen by occluding the 12F entry site. Furthermore, collagen-induced coagulation was facilitated.

Clinical and endoscopic characterization of depressed gastric adenoma

BACKGROUND AND STUDY AIM

Depressed gastric adenoma remains poorly characterized because it is rare, and is infrequently detected by endoscopy. The aim of this study was to elucidate clinical and endoscopic characteristics of depressed adenoma of the stomach.

PATIENTS AND METHODS

95 consecutive patients who underwent endoscopic resection of gastric adenomas were studied. Gastric adenomas, diagnosed according to the Vienna classification, were endoscopically classified into two types: depressed and protruding adenomas. In order to clarify endoscopic features of gastric adenomas, we performed indigo carmine chromoendoscopy as well as magnifying endoscopy with narrow band imaging, which yields clear images of mucosal microvasculature.

RESULTS

12% of 100 gastric adenomas resected from 95 patients were depressed adenomas. Age and gender were comparable between patients with each type. Depressed adenomas (15.9 +/- 6.2 mm) were significantly larger in diameter than protruding adenomas (10.6 +/- 8.0 mm) (P = 0.01). Half of depressed adenomas were reddish in color, whereas only 18% of protruding adenomas were reddish. Magnifying endoscopy with narrow band imaging showed that 71% of depressed adenomas had a regular ultrafine network pattern of mucosal microvasculature, which was not seen in protruding adenomas. Intramucosal carcinomas were more frequently found in depressed adenomas (25%) than in protruding adenomas (4.5%).

CONCLUSIONS

In comparison with protruding adenomas, depressed adenomas were rare and appeared endoscopically as large and reddish with a specific regular ultrafine network pattern of mucosal microvasculature. Depressed adenomas should be endoscopically resected because intramucosal carcinomas were found in a quarter of them.

Stress cardiomyopathy mimicking acute coronary syndrome: case presentation and review of the literature

Stress cardiomyopathy is a novel clinical syndrome affecting predominantly elderly female patients. It is characterized by severe reversible left ventricular dysfunction demonstrating a peculiar pattern of extensive apical wall motion abnormality known as "apical ballooning". The syndrome is typically precipitated by acute severe emotional, psychological or physical stress. It mimics acute coronary syndrome exhibiting typical clinical and electrocardiographic features of acute myocardial infarction. At angiography, however, significant coronary artery disease is invariably excluded. In the acute phase, the syndrome may be complicated by cardiogenic shock or ventricular fibrillation. Clinical data indicate that the disease is associated with an extensive increase of endogenous cathecholamine levels which may exhibit a direct toxic effect on the myocytes causing non-ischemic myocardial "stunning". This mechanism may have important implications for the management of patients in the acute phase of the disease. The prognosis of stress cardiomyopathy, however, seems favorable with recovery of global and regional myocardial function within a few weeks in the vast majority of patients. Yet, long-term outcome data in larger patient populations are lacking. We report the case of a female patient presenting with stress cardiomyopathy and review the current knowledge of the disease.

Impact of ECG Gating in Contrast-Enhanced MR Angiography for the Assessment of the Pulmonary Veins and the Left Atrium Anatomy

PURPOSE

Implementation of ECG gating in contrast-enhanced MR angiography (ceMRA) for improved visualization of the pulmonary veins, the left atrium, and the thoracic vessels.

MATERIALS AND METHODS

CeMRA was performed on twelve patients with a history of recurrent atrial fibrillation for the purpose of an intra-individual comparison with and without ECG gating on a 1.5 Tesla MR system (Gyroscan Intera, Philips Medical Systems, Best, NL). Objective image quality parameters such as the signal-to-noise ratio (SNR) of the blood and the contrast-to-noise ratio (CNR) between the blood and myocardium or lung parenchyma were analyzed. The contour sharpness of the pulmonary veins, left atrium, ascending aorta, and pulmonary trunk was also measured. In addition, the artifact level was subjectively assessed by two observers blinded with respect to the sequence parameters. Statistically significant differences (p < 0.05) between the procedures were analyzed using the Wilcoxon test and Pearson Chi-square test.

RESULTS

The use of ECG gating in ceMRA significantly reduced artifacts caused by cardiac motion and vessel pulsation. This in turn lead to a significant increase in the contour sharpness of the left atrium and the thoracic vessels. In addition, higher SNR and CNR were found using ECG-gated ceMRA compared to standard ceMRA.

CONCLUSION

The use of ECG gating in ceMRA results in artifact-free and sharper delineation of the structures of the heart and thoracic vessels.

Analysis of myocardial deformation based on pixel tracking in two dimensional echocardiographic images enables quantitative assessment of regional left ventricular function

OBJECTIVE

To evaluate whether myocardial strain and strain rate calculated from two dimensional echocardiography by automatic frame-by-frame tracking of natural acoustic markers enables objective description of regional left ventricular (LV) function.

METHODS

In 64 patients parasternal two dimensional echocardiographic views at the apical, mid-ventricular and basal levels were obtained. An automatic frame-by-frame tracking system of natural acoustic echocardiographic markers was used to calculate radial strain, circumferential strain, radial strain rate and circumferential strain rate for each LV segment in a 16 segment model. Cardiac magnetic resonance imaging (cMRI) was performed to define segmental LV function as normokinetic, hypokinetic or akinetic.

RESULTS

Image quality was sufficient for adequate strain and strain-rate analysis from two dimensional echocardiographic images obtained from parasternal views in 88% of segments. Obtained radial strain data were highly reproducible and analysis was affected by only small intraobserver (mean 4.4 (SD 1.6)%) and interobserver variabilities (7.3 (2.5)%). Each of the analysed strain and strain-rate parameters was significantly different between segments defined as normokinetic, hypokinetic or akinetic by cMRI (radial strain 36.8 (10.5)%, 24.1 (7.5)% and 13.4 (4.8)%, respectively, p < 0.001). Peak systolic radial strain enabled detection of hypokinesis or akinesis with a sensitivity of 83.5% and a specificity of 83.5% (cut off value 29.1%, receiver operating characteristic (ROC) curve area 0.905, 95% CI 0.883 to 0.923). Peak systolic radial strain analysis also enabled detection of akinesis versus hypokinesis with a sensitivity of 82.7% and a specificity of 94.5% (cut off value 21.0%, ROC curve area 0.946). Peak systolic radial strain-rate analysis was less accurate than peak systolic radial strain analysis to detect cMRI-defined segmental function abnormalities. The accuracy of peak systolic circumferential strain and strain rate was similar to that of corresponding radial parameters.

CONCLUSIONS

Frame-by-frame tracking of acoustic markers in two dimensional echocardiographic images enables accurate analysis of regional systolic LV function.

[Heart tumors: magnetic resonance imaging and multislice spiral CT]

Transthoracic echocardiography is usually the initial diagnostic test in patients with a suspected cardiac mass. However, this technique is restricted by its small field of views and insufficient acoustic window in some patients. Magnetic resonance imaging (MRI) and, since its introduction, multislice spiral computed tomography allow for detailed delineation of intra and pericardiac tumors, their extent, and their influence on cardiac function. Primary benign and malignant cardiac tumors have several characteristic features in MR imaging. Assessment of such features may narrow down the differential diagnosis or even allow for reliable diagnosis in selected cases. Many such features can also be assessed using MSCT. This article provides an overview of examination protocols of MRI and CT for cases in which a cardiac mass is suspected and describes the appearance of primary and secondary cardiac masses as well as intracavitary thrombi.

The transcriptional landscape of the mammalian genome

This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development.

Pharmacological study of BRS, a new bicarbonated Ringer's solution, in haemorrhagic shock dogs

BACKGROUND AND OBJECTIVES

Sodium bicarbonate is the most physiological alkalinizing agent. The effect of a new bicarbonated Ringer's solution (BRS) containing Mg2+, on metabolic acidosis and serum magnesium abnormality were evaluated and compared with those of acetated Ringer's (ARS), lactated Ringer's (LRS) and Ringer's (RS) solutions in an experimental haemorrhagic shock model with dogs.

METHODS

Animals were randomly divided into six groups (n = 6 in each group), a sham-operated group, an operated group without infusion, and 4 operated groups with infusion (BRS, ARS, LRS and RS groups). Each RS was intravenously administered at 60 mL kg(-1) h(-1) for 1.5 h. Arterial blood gases, plasma electrolytes and cardiovascular parameters were analysed.

RESULTS

BRS significantly improved blood base excess values, which were decreased by blood-letting, faster and more markedly than did LRS and RS (BRS--6.3 +/- 0.5 mEq L(-1); LRS--9.2 +/- 1.1 mEq L(-1); RS--12.4 +/- 1.0 mEq L(-1) at the end of infusion). The alkalinizing effect of BRS tended to be better than that of ARS but not significantly so. The serum Mg2+ concentration was well-maintained by BRS as compared to other RS (BRS 1.5 +/- 0.0 mgdL(-1); ARS 1.2 +/- 0.0mgdL(-1); LRS 1.1 +/- 0.0mgdL(-1); RS 1.3 +/- 0.1 mgdL(-1), at the end of infusion).

CONCLUSIONS

These results suggest that BRS is a suitable perioperative solution for metabolic acidosis and serum electrolyte balance among RS tested.

Human artificial chromosome (HAC) vector provides long-term therapeutic transgene expression in normal human primary fibroblasts

Human artificial chromosomes (HACs) segregating freely from host chromosomes are potentially useful to ensure both safety and duration of gene expression in therapeutic gene delivery. However, low transfer efficiency of intact HACs to the cells has hampered the studies using normal human primary cells, the major targets for ex vivo gene therapy. To elucidate the potential of HACs to be vectors for gene therapy, we studied the introduction of the HAC vector, which is reduced in size and devoid of most expressed genes, into normal primary human fibroblasts (hPFs) with microcell-mediated chromosome transfer (MMCT). We demonstrated the generation of cytogenetically normal hPFs harboring the structurally defined and extra HAC vector. This introduced HAC vector was retained stably in hPFs without translocation of the HAC on host chromosomes. We also achieved the long-term production of human erythropoietin for at least 12 weeks in them. These results revealed the ability of HACs as novel options to circumvent issues of conventional vectors for gene therapy.

Inversion Prepared Coronary MR Angiography: Direct Visualization of Coronary Blood Flow

PURPOSE

Visualization of coronary blood flow by means of a slice-selective inversion pre-pulse in concert with bright-blood coronary MRA.

MATERIALS AND METHODS

Coronary magnetic resonance angiography (MRA) of the right coronary artery (RCA) was performed in eight healthy adult subjects on a 1.5 Tesla MR system (Gyroscan ACS-NT, Philips Medical Systems, Best, NL) using a free-breathing navigator-gated and cardiac-triggered 3D steady-state free-precession (SSFP) sequence with radial k-space sampling. Imaging was performed with and without a slice-selective inversion pre-pulse, which was positioned along the main axis of the coronary artery but perpendicular to the imaging volume. Objective image quality parameters such as SNR, CNR, maximal visible vessel length, and vessel border definition were analyzed.

RESULTS

In contrast to conventional bright-blood 3D coronary MRA, the selective inversion pre-pulse provided a direct measure of coronary blood flow. In addition, CNR between the RCA and right ventricular blood pool was increased and the vessels had a tendency towards better delineation. Blood SNR and CNR between right coronary blood and epicardial fat were comparable in both sequences.

CONCLUSION

The combination of a free-breathing navigator-gated and cardiac-triggered 3D SSFP sequence with a slice-selective inversion pre-pulse allows for direct and directional visualization of coronary blood flow with the additional benefit of improved contrast between coronary and right ventricular blood pool.

180 EFFICIENT GENE SILENCING USING siRNA IN MOUSE AND MONKEY ES CELLS AND DIFFERENTIATION

Gene silencing by RNA interference (RNAi) using small interfering RNAs (siRNAs) and short hairpin RNAs (shRNAs) has become a valuable genetic tool for silencing specific genes in various organisms. As compared with transgene-based RNAi using shRNA expression vectors, chemically synthesized siRNAs have an advantage in that they do not modify genome organization. This nature is ideal as a differentiation method for embryonic stem (ES) cells. The objective of this work was to develop an efficient method to repress a specific gene expression in mouse and monkey ES cells using chemically synthesized siRNA, and to investigate whether this transient gene silencing can be used as a new differentiation method of ES cells. First, we tried to knock down the expression of enhanced green fluorescent protein (EGFP) gene in GFP-expressing mouse ES cells. We found that lipofection was effective to deliver siRNA into mouse ES cells. Suppression of EGFP expression was observed by fluorescence microscopy after 24 h of transfection and the silencing continued at least for 5 days. FACS analysis revealed that 86% of cells showed suppression of EGFP at 48 h after transfection. Then we tried to suppress endogenous gene Oct4 that plays an important role in the maintenance of pluripotency and the lineage commitment in mouse ES cells. We performed RT-PCR analysis and western blotting to assay for Oct4 mRNA and protein at 24, 48, 72, and 96 h after transfection. Hand1 and Cdx2, transcription factors implicated in trophoblast differentiation, were also analyzed. RT-PCR analysis showed a reduced level of Oct4 mRNA at 24–96 h. Reduction of Oct4 protein was confirmed by western blotting and the reduced level was still maintained at 96 h after transfection. RT-PCR analysis also showed up-regulation of Hand1 and Cdx2 concomitant with the suppression of Oct4. Furthermore, ES cells changed their morphology into a large and flattened shape that is characteristic of trophoblast cells. These results suggested that the transient suppression of Oct4 induced differentiation of mouse ES cells to trophectoderm cells as expected. Therefore our data imply that the chemically synthesized siRNA can be used to differentiate ES cells. Next, we tried to suppress EGFP and Oct4 in monkey ES cells. In monkey ES cells, we found that the Sendai virus (hemagglutinating virus of Japan, HVJ) envelope was suitable to deliver siRNA into cells. With this method, we detected efficient silencing of EGFP and Oct4 by fluorescence microscopy, RT-PCR analysis, and western blotting. In the case of monkey ES cells, however, no morphological change was observed by Oct4 suppression at 96 h after transfection. These results suggest possible diversity between murine and primate ES cells in the differentiation process. This work was supported by grants from the Ministry of Education, Science, Sports, and Culture (14580798, 13358014 and 14380382).

MR features of masticatory muscles in adenoid cystic carcinoma involving the masticator space

Adenoid cystic carcinoma (ACC) is known for its slow-growing but severely infiltrative nature with little tissue reaction. Although the masticatory muscles are often involved, their imaging features have not been well elucidated. We hereby report three patients with widespread ACC, which initially appeared with trismus and/or temporomandibular symptoms and involved the masticator space. Possible features of masticator space involvement are presented on magnetic resonance (MR) images. Masticatory muscle changes on MR images consisted of two aspects, namely, denervation changes and direct tumour invasion.

Correlation of circulating tumor cells with tumor size and metastatic load in a spontaneous lung metastasis model

BACKGROUND

The prognostic value of circulating tumor cells remains unclear since, in principle, most tumor cells are unable to survive in the bloodstream. The aim of the study was to establish a system that can be used to investigate the metastatic process in more detail, with emphasis on circulating tumor cells.

MATERIALS AND METHODS

Human colon carcinoma cells (HT29) were transplanted into severe-combined-immunodeficient (scid) mice. The metastatic load in the blood was investigated using the human-specific carcinoembryonic antigen (CEA) as target for quantitative polymerase-chain-reaction (PCR).

RESULTS

A close correlation between the weight of the primary tumor and the number of circulating tumor cells was detected (r=0.7240; p<0.0001). Moreover, the number of circulating tumor cells and the actual number of spontaneous lung metastases was related (r=0.8283; p<0.0001).

CONCLUSION

A tumor xenotransplantation model is presented that allows for a detailed investigation of the metastatic process in three different compartments: the primary tumor bed, the bloodstream and the target organ of metastatic residency.