Development of a highly efficient implanted thermal ablation device: in vivo experiment in rat liver

OBJECTIVES

To evaluate an implanted thermal ablation device that can be heated with high efficiency using a resonant circuit as the implant.

METHODS

16 rats were used. The implants, adjusted at a resonance frequency of 4 MHz, were fixed on the surface of the liver of rats under laparotomy. In 14 of 16 rats, an alternating magnetic field (AMF) was applied for 6 min with an output of 300 W from outside the body using a ferrite core applicator. The implant temperature during AMF exposure was measured. The 14 rats were divided into 5 groups, depending on time from AMF application until they were sacrificed (1 h, 1 day, 3 days, 7 days and 1 month after application). Two rats not exposed to AMF were used as controls. Livers were removed and evaluated; the cross-sectional area and width of the ablated region were measured.

RESULTS

During AMF exposure, the implant temperature rose to 127.8±39.3 °C (mean±standard deviation). The cross-sectional area of the ablated region was largest after 1 day and tended to decrease with time. The widths of the ablated region were 4.87±0.22 mm, 4.15±0.36 mm, 3.67±0.58 mm and 3.24±0.16 mm in the 1 day, 3 day, 7 day and 1 month groups, respectively. No significant differences (p<0.05) were seen in either cross-sectional area or width of the ablated region.

CONCLUSION

Sufficient heat for ablation was obtained in vivo using a newly developed implanted thermal ablation device. This device may be a new option for thermal ablation therapy.

The non-vascularised fibular graft: a simple and successful method of reconstruction of the pelvic ring after internal hemipelvectomy

Internal hemipelvectomy is a standard treatment for malignant tumours of the pelvis. Reconstruction using a non-vascularised fibular graft is relatively straightforward compared to other techniques. We describe the surgical and functional outcomes for a series of ten patients who underwent an internal hemipelvectomy (type I or I/IV) with reconstruction by a non-vascularised fibular graft between 1996 and 2009. A key prerequisite for this procedure was a preserved sciatic notch, confirmed pre-operatively on MRI. Graft-host union was achieved in all patients with a single fibular graft, and in the lower graft where two grafts had been used. The mean time to union was 7.3 months (3 to 12). The upper graft did not unite in four of six cases where two grafts had been used. Seven patients were eventually able to walk without a stick. The mean post-operative Musculoskeletal Tumour Society score was 75.4% (16.7 to 96.7). There were no cases of deep post-operative infection. The mean pelvic shortening was 0.9 cm (0.2 to 3.4). Recurrent tumour occurred in three cases, and death from tumour-related disease occured in one. Patients who need an internal hemipelvectomy will do well if their pelvic ring is reconstructed with a non-vascularised fibular graft. The complication rate is low, and they attain a good functional outcome.

The significance of size change of soft tissue sarcoma during preoperative radiotherapy

AIM

To assess the significance of change in tumour size during preoperative radiotherapy in patients with soft tissue sarcoma (STS).

METHODS

A retrospective review of 91 cases with STS was performed. Inclusion criteria were localised extremity and truncal STS with measurable disease, older than 18 years, treated with preoperative radiotherapy and wide local excision, in the period between January 1966 and December 2005. Patients with head and neck STS, or who received neoadjuvant chemotherapy were excluded. A difference in excess of 10% of the greatest tumour diameter of the pre-radiotherapy and the post-radiotherapy MRI scans was considered as change in tumour size.

RESULTS

Increase in tumour size was noted in 28 patients (31%) (Group 1). No change or decrease in size was observed in 63 patients (Group 2). There were no significance differences in local control or overall survival rates between the 2 groups. The estimated overall actuarial local recurrence free, event-free and overall survival rates were 90.5%, 64.4%, 62.9% in Group 1, and 85.7%, 60.8%, 68.9% in Group 2 respectively.

CONCLUSION

Increase in tumour size during preoperative radiotherapy for soft tissue sarcoma does not seem to associate with inferior local tumour control or compromise survival. Lack of reduction in tumour size is not necessarily a sign of lack of response to preoperative radiotherapy.

Pim-1 controls NF-kappaB signalling by stabilizing RelA/p65

Post-translational modification and degradation of proteins by the ubiquitin-proteasome system are key regulatory mechanisms in cellular responses to various stimuli. The NF-kappaB signaling pathway is controlled by the ubiquitin-mediated proteolysis. RelA/p65, which is a main subunit of NF-kappaB, is ubiquitinated for degradation by SOCS-1, but the functional mechanism of its ubiquitination remains poorly understood. In this study we show that phosphorylation of RelA/p65 at Ser276 prevents its degradation by ubiquitin-mediated proteolysis. In contrast, impairment of Ser276 phosphorylation affects constitutive degradation of RelA/p65. Importantly, we identify Pim-1 as a further kinase responsible for the phosphorylation of RelA/p65 at Ser276. Depletion of Pim-1 hinders not only Ser276 phosphorylation but also transactivation of RelA/p65 target genes. We also show that Pim-1 contributes to recruitment of RelA/p65 to kappaB-elements to activate NF-kappaB signalling after TNF-alpha stimulation. In concert with these results, the knockdown of Pim-1 impairs IL-6 production and augments apoptosis by interfering RelA/p65 activation. These findings provide a model in which Pim-1 phosphorylation of RelA/p65 at Ser276 allows defense against ubiquitin-mediated degradation and whereby exerts activation of NF-kappaB signalling.

Normal pituitary stalk: high-resolution MR imaging at 3T

BACKGROUND AND PURPOSE

Knowing the normal imaging appearance of the pituitary stalk is important for the diagnosis of pituitary infundibular lesions, and more accurate assessment of the stalk may be possible at 3T than at 1.5T. Our purpose was to evaluate the normal pituitary stalk by use of high-resolution MR imaging at 3T.

MATERIALS AND METHODS

Sagittal MPRAGE images and high-resolution oblique-axial T2-weighted images of the pituitary stalk were acquired in 29 healthy volunteers (16 men and 13 women; mean age, 28 years; age range, 21-43 years) at 3T. The diameter and length of the pituitary stalk and the depth of the infundibular recess were measured. Signal intensity of the stalk was visually evaluated on T2-weighted images.

RESULTS

The AP and transverse diameters of the pituitary stalk were 2.32 +/- 0.39 mm and 2.16 +/- 0.37 mm at the pituitary insertion, respectively, and 3.25 +/- 0.43 mm and 3.35 +/- 0.44 mm at the level of the optic chiasm. No significant differences were observed between the AP and transverse diameters at each level. The length of the stalk was 5.91 +/- 1.24 mm, and the depth of the infundibular recess was 4.69 +/- 0.87 mm. The stalk showed central hyperintensity with a peripheral rim of isointensity in 20 subjects (69%) and homogeneous isointensity in 9 subjects (31%).

CONCLUSIONS

The data of the current study can serve as standard measurements of the normal pituitary stalk. The central hyperintensity and peripheral rim may represent the infundibular stem and pars tuberalis, respectively.

Three-dimensional double-echo steady-state (3D-DESS) magnetic resonance imaging of the knee: contrast optimization by adjusting flip angle

BACKGROUND

The three-dimensional double-echo steady-state (3D-DESS) sequence is being used to investigate sequence parameters for the assessment of knee cartilage by magnetic resonance imaging (MRI). With the flip angle (FA) values that are commonly used, contrast between cartilage and synovial fluid may be too low to delineate minor lesions of the cartilage surface.

PURPOSE

To investigate the value of FA maximizing contrast between cartilage and synovial fluid using the 3D-DESS sequence.

MATERIAL AND METHODS

In 10 healthy volunteers (five men, five women; age range 23-48 years), 3D-DESS imaging was performed to capture median sagittal sections of the knee by adjusting FA from 10 degrees to 90 degrees. Cartilage-synovial fluid contrast-to-noise ratio (CNR) was measured to determine the value of FA maximizing CNR. Water-excitation pulse was used to suppress fat signals. MRI was performed at 1.0 T using a circular polarization flex coil.

RESULTS

Cartilage-synovial fluid CNR was highest with 90 degrees FA, yielding images with good contrast between cartilage and synovial fluid.

CONCLUSION

Simply by increasing FA to 90 degrees in 3D-DESS imaging, the contrast between cartilage and synovial fluid increased substantially. Subtle cartilage lesions may thus be detectable using 3D-DESS sequences.

Hemispheric asymmetry of the arcuate fasciculus: a preliminary diffusion tensor tractography study in patients with unilateral language dominance defined by Wada test

OBJECTIVE

Lateralization of language function is a prominent feature of human brain function, and its underlying structural asymmetry has been recently reported in normal right-handed subjects. By means of diffusion tensor tractography (DTT), we investigated the asymmetry of the language network, namely, the arcuate fasciculus in patients in whom the unilateral language dominance was defined by Wada test.

METHODS

DTT was performed in 24 patients with a focal lesion or an epileptic focus outside the C-shaped segment of the arcuate fasciculus. The arcuate fasciculus was reconstructed by placing two regions-of-interest in the deep white matter lateral to the corona radiata. The pathway was then divided into one terminating in the temporal lobe (FT tract) and the other in the parietal lobe (FP tract). The relative number and volume of the FT and FP tracts in each hemisphere were submitted to repeated measure ANOVA separately, with the hemisphere as a within-subject factor and with the side of pathology as a between subject factor.

RESULTS

The FT tract showed a significantly larger number and volume in the language dominant hemisphere than in the non-dominant hemisphere, while, for the FP tract, no significant hemispheric difference was observed in the relative number or volume. There was a tendency that the FT tract was less lateralized when the pathology was located in the dominant hemisphere than in the non-dominant hemisphere.

CONCLUSION

Dominance of the FT tract in the language dominant hemisphere was demonstrated for the first time in a patient population and implicated a clinical utility of DTT for non-invasive evaluation of language lateralization. Our preliminary study might indicate reorganization of the language network in conjunction with pathology.

Molecular epidemiological and mutational analysis of DNA mismatch repair (MMR) genes in endometrial cancer patients with HNPCC-associated familial predisposition to cancer

Recently, a high rate of endometrial cancer has been reported in women with hereditary non-polyposis colorectal cancer (HNPCC), suggesting a relationship between familial endometrial cancers and HNPCC. Familial endometrial cancers constitute only about 0.5% of all endometrial carcinomas and it is essential to examine family histories in detail. A mutational analysis of three DNA mismatch repair (MMR) genes (hMLH1, hMSH2 and hMSH6) in patients with endometrial cancer who meet our criteria for familial predisposition to HNPCC-associated endometrial cancers was performed. Mutations were detected in 18 of the 120 patients (15.0%). Most HNPCC-related endometrial cancers do not meet the New Amsterdam Criteria for HNPCC. These clinical criteria may identify only some HNPCC-associated endometrial cancers. Establishing the correct family history for endometrial cancer patients is important for diagnosing familial endometrial carcinomas. An analysis of MMR genes may be useful for patients with endometrial cancer showing familial aggregation. In addition, gynecologists must be accurately informed, and it is important to perform large-scale, multicenter studies both nationwide and internationally.

Aurora kinase B is a predictive factor for the aggressive recurrence of hepatocellular carcinoma after curative hepatectomy

BACKGROUND

Patterns of cancer recurrence hold the key to prognosis after curative resection. This retrospective study aimed to identify a predictor and therapeutic candidate for aggressive recurrence of hepatocellular carcinoma (HCC).

METHODS

Primary HCC tissues from 107 patients who had curative resection were analysed. Genome-wide gene expression profiles were investigated using a microarray technique, and clustering analysis was carried out based on the first diagnosis of recurrence according to the Milan criteria. Immunohistochemical expression and array-based comparative genomic hybridization (array-CGH) were also assessed.

RESULTS

Microarray analysis revealed overexpression of Aurora kinase B, a chromosome passenger protein kinase, as the most significant predictor of the aggressive recurrence of HCC. Aurora kinase B protein expression was significantly associated with aggressive recurrence (P < 0.001) and prognosis (P < 0.001). Multivariable analysis identified Aurora kinase B as the only independent predictor of aggressive recurrence of HCC (P = 0.031). Array-CGH analysis showed that genomic instability was closely related to Aurora kinase B expression (P = 0.011).

CONCLUSION

Aurora kinase B is an effective predictor of aggressive HCC recurrence, in relation to the genomic instability. It might be worth considering as a molecular target for the adjuvant therapy of HCC.

A CRM1-mediated nuclear export signal governs cytoplasmic localization of BRCA2 and is essential for centrosomal localization of BRCA2

Germ-line mutations of the BRCA2 gene cause inherited susceptibility to breast and ovarian cancers. BRCA2 contains two nuclear localization signals, predominantly localizes in the nucleus and plays significant roles in DNA double-strand break repair. Recently, we reported that BRCA2 localizes to the centrosomes during the S and early M phases of the cell cycle. In this study, for the first time, we identified a functional nuclear export sequence (NES1; (1383)DLSDLTFLEVA(1393)) in BRCA2. The green fluorescent protein (GFP)-NES1 fusion protein was localized in the cytoplasm and could be blocked by the chromosomal region maintenance 1-specific export inhibitor leptomycin B. Mutation of a leucine residue in the NES1 motif to alanine (L1384A) resulted in both cytoplasmic and nuclear localization of the GFP-NES1 fusion protein and a nuclear accumulation of ectopic full-length BRCA2-FLAG. Moreover, treatment of cells with leptomycin B decreased centrosomal localization of BRCA2. Finally, by microinjection of an anti-BRCA2 antibody into the cytoplasm of HeLa S3 cells, we found that depletion of normal BRCA2 proteins in the cytoplasm leads to centrosome amplification and binucleated cells. Our results suggest that disruption of the NES function by genetic changes results in deregulation of BRCA2 export, which ultimately leads to centrosome disorder.