BH3-mimetic drugs prevent tumour onset in an orthotopic mouse model of hepatoblastoma

Drug resistance and metastasis remain major challenges in the treatment of high-risk hepatoblastoma (HB) and require the development of alternative therapeutic strategies. Modulation of apoptosis in HB cells enhances the sensitivity of these cells towards various drugs and has been discussed to enforce treatment. We investigated the impact of apoptosis sensitisers, BH3-mimetics, on the interaction between the host and HB to reduce tumour growth and dissemination while enhancing immunity. BH3-mimetics, such as obatoclax and ABT-737, enhanced the apoptosis-inducing effect of TRAIL and TNF-α resistant HB cells (HepT1 and HUH6). Tumour cell migration was inhibited by ABT-737 and more markedly by obatoclax. In an orthotopic model of HB, tumour uptake was reduced when the cells were pretreated with low concentrations of obatoclax. Only 1 of 7 mice developed HB in the liver, compared with an incidence of 0.8 in the control group. In summary, our study showed that apoptosis sensitisers had broader effects on HB cells than expected including migration and susceptibility to cytokines in addition to the known effects on drug sensitization. Sensitising HB to apoptosis may also allow resistant HB to be targeted by immune cells and prevent tumour cell dissemination.

Weighted simultaneous algebraic reconstruction technique for tomosynthesis imaging of objects with high-attenuation features

PURPOSE

This paper introduces a nonlinear weighting scheme into the backprojection operation within the simultaneous algebraic reconstruction technique (SART). It is designed for tomosynthesis imaging of objects with high-attenuation features in order to reduce limited angle artifacts.

METHODS

The algorithm estimates which projections potentially produce artifacts in a voxel. The contribution of those projections into the updating term is reduced. In order to identify those projections automatically, a four-dimensional backprojected space representation is used. Weighting coefficients are calculated based on a dissimilarity measure, evaluated in this space. For each combination of an angular view direction and a voxel position an individual weighting coefficient for the updating term is calculated.

RESULTS

The feasibility of the proposed approach is shown based on reconstructions of the following real three-dimensional tomosynthesis datasets: a mammography quality phantom, an apple with metal needles, a dried finger bone in water, and a human hand. Datasets have been acquired with a Siemens Mammomat Inspiration tomosynthesis device and reconstructed using SART with and without suggested weighting. Out-of-focus artifacts are described using line profiles and measured using standard deviation (STD) in the plane and below the plane which contains artifact-causing features. Artifacts distribution in axial direction is measured using an artifact spread function (ASF). The volumes reconstructed with the weighting scheme demonstrate the reduction of out-of-focus artifacts, lower STD (meaning reduction of artifacts), and narrower ASF compared to nonweighted SART reconstruction. It is achieved successfully for different kinds of structures: point-like structures such as phantom features, long structures such as metal needles, and fine structures such as trabecular bone structures.

CONCLUSIONS

Results indicate the feasibility of the proposed algorithm to reduce typical tomosynthesis artifacts produced by high-attenuation features. The proposed algorithm assigns weighting coefficients automatically and no segmentation or tissue-classification steps are required. The algorithm can be included into various iterative reconstruction algorithms with an additive updating strategy. It can also be extended to computed tomography case with the complete set of angular data.

The activity of γδ T cells against paediatric liver tumour cells and spheroids in cell culture

BACKGROUND

Chemoresistance and advanced tumour stage at time of diagnosis are the major reasons for poor treatment results in hepatoblastoma (HB) and paediatric hepatocellular carcinoma (HCC). Positive results with transplantation of liver and bone marrow revealed the impact of the immune system on the treatment of liver malignancies.

AIM

Cytotoxic-immune-cells-like natural killer (NK) and T cells are major player in the defence against developing tumours. This study aimed to specifically analyse the ability of ex-vivo expanded γδ T cells to recognise and lyse HB and HCC cell lines in coculture assays.

METHODS

Cell viability after treatment with γδ T cells was evaluated with two HB (HUH6 and HepT1) and one HCC cell line (HC-AFW1) using a MTT-based cytotoxicity assay. The binding of T cells to target cells was monitored using immunofluorescence microscopy.

RESULTS

Incubation of hepatic tumour cell lines with γδ T cells led to a significant decrease in tumour cell viability. This was enhanced by zoledronic acid and histone deacetylase inhibitors. MT110, an EpCAM/CD3-bispecific BiTE antibody could bluntly enhance tumour cell lysis close to completion. γδ T cells efficiently interacted with HB and HCC cells in a spheroid culture model.

CONCLUSION

Bispecific antibodies such as MT110 might be used to intensify the antitumoural effect of γδ T cells in context of adoptive immune cell transfer. Optimised immunotherapeutic strategies might therefore improve the outcome of high risk hepatoblastoma and hepatocellular carcinoma.

Dual-Source computed tomography of the chest in the surgical planning of repeated cardiac surgery

AIM

When reoperative cardiac surgery is indicated, detailed, three-dimensional imaging of the thorax permits accurate depiction of cardiac anatomy and vascular structures potentially increasing the safety of the surgical procedure. We sought to evaluate the contribution of dual-source multidetector-row computed tomography (DSCT) of the heart and thorax in planning repeated open heart surgery.

METHODS

Twenty-eight patients (mean age, 68 years) scheduled for repeated cardiac surgery who had undergone previous coronary artery bypass grafting (n=19) or cardiac valve replacement (8) or combined valvular and bypass surgery (1) underwent contrast-enhanced ECG-gated DSCT (Somatom Definition, Siemens Medical Solutions) of the whole thorax with a temporal resolution of 82 ms and a spatial resolution of 0.4 mm³. The indication for repeated surgery was bypass surgery (N.=6), valve replacement (16), combined bypass and valvular surgery (5) or other reasons (1). Assessment of surgical risk based on DSCT data were performed in terms of the relation of the ascending aorta and cardiac structures to the expected median sternotomy line, graft patency and anatomic course, and the degree of calcification of the ascending aorta and coronary arteries.

RESULTS

DSCT findings led to a change of surgical approach for 9/28 (32.1%) patients (non-midline incision, N.=3; surgery performed under circulatory arrest, N.=5; peripheral arterial cannulation before sternotomy, N.=1) and cancellation of surgery for 4/28 (14.3%) patients (heavy aortic and coronary calcifications impeding bypass surgery, N.=2; right heart or aortic aneurysm in close proximity to the sternum in high risk patients, N.=2). The planned surgical approach remained unchanged after DSCT for the remaining15/28 (53.6%) patients. Of 54 bypass graft conduits (20 arterial, 34 venous) visualized on DSCT in 20 patients after previous bypass grafting, 16 arterial and 24 venous grafts were patent, while 4 arterial and 10 venous grafts were occluded.

CONCLUSION

DSCT of the heart and thorax is an effective, non-invasive tool for the preoperative planning of repeated cardiac surgery. The technique provides significant information to modify the surgical approach and may increase the safety of the procedure.

Crediting Treatments for Good Outcomes That Would Have Happened Anyway

Background. In some patient populations, many would experience good outcomes even if untreated (described as a small baseline risk). It appears that treatments for populations with small baseline risks are perceived as more effective than those for populations with large baseline risks: in essence, treatments are credited for good outcomes that would have happened anyway. Previous research failed to control for differences in treatment effects. Objective. To evaluate if the baseline risk of developing an acute condition influences the perceived effectiveness of preventive treatments besides the genuine treatment effect. Methods. In study 1 ( n = 1100) and study 2 ( n = 336), general population samples were shown information that systematically differed in size of treatment effect (absolute and relative risk reduction) and the size of the baseline risk of developing a condition. In study 3, medical students ( n = 110) were shown treatments that systematically differed in the size of the baseline risk of developing a condition and the type of condition to be prevented (i.e., migraines, heart disease, and pancreatic cancer). Measures included the perceived effectiveness of treatments, intentions to use these treatments, and numeracy. Results. The baseline risk of developing an acute condition influenced the perceived effectiveness of treatments (study 1: F1,1043 = 66.17, P < 0.001; study 2: F1,329 = 16.574, P < 0.001; study 3: F1,98 =14.31, P < 0.001) and, in turn, intention to use the treatment (study 1: F1,1045 = 7.12, P = 0.008). It caused treatments to be judged as unduly ineffective when the baseline risk was large and vice versa. The influence was independent of treatment effect and was not moderated by numeracy. Conclusions. Treatments for populations with a small baseline risk of developing the condition are perceived as more effective than those for populations with a large baseline risk.

Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties

INTRODUCTION

Osteotomy of the anterior tibial tubercle (TT) is well known as the approach to difficult knees, in particular those with a low patella, but it has a poor reputation.

PATIENTS AND METHODS

This technique was used 21 times in 20 patients (10 males and 10 females) with a mean age of 71 years (range, 42-90 years) for 14 prosthesis revisions (three for septic loosening, 11 for aseptic loosening) and seven knees that had not anteriorly received prior implants (three osteotomies, one synovectomy). The surgical technique included a long (7 cm), thick (>1 cm) fragment retaining its lateral muscle hinge with compression fixation using two screws. In cases with a low patella, the TT was proximally displaced, with amplitude limited by the tibial baseplate. Follow-up was clinical and radiological, lasting a mean 54 months (range, 8-195 months). The clinical results were assessed using the IKS score and the radiological results using the measurement of the patellar index according to the protocol described during the Lyon Knee Days.

RESULTS

The mean preoperative IKS scores were: knee, 57.5±22.4; function, 42.6±21.5 (total, 100±33.9); postoperative scores: knee, 84±11.6; function 65±28 (total, 149±32.9). The joint range of motion increased from 73±34.9 to 88±21.1 for a mean gain of 15±23.1. We found a traumatic nondisplaced tibia fracture around a tibial stem, treated conservatively, two stress fractures of the immediate proximal part overhanging the TT with no consequences, one case of stiffness (not related to the osteotomy), and one case of localized skin necrosis on a knee that had undergone several surgeries (secondary scarring). No cases of malunion or migration of the TT were noted. The mean deliberate proximal migration obtained was 13 mm±6 (range, 8-33 mm). The patellar index increased from 0.18±0.20 (range, -0.39 to 0.57) to 0.33±0.19 (range, -0.13 to 0.60).

DISCUSSION

This series shows that the indications are rare but invaluable, facilitating the approach and most particularly making it possible to modify the position of the patella, thus contributing to increasing the joint range of motion. Fixation with two screws carries no risk of disassembly if the technique is rigorous. Patellar translation is limited by the tibial tray.