A patient tumour-on-a-chip system for personalised investigation of radiotherapy based treatment regimens.

Development of personalised cancer models to predict response to radiation would benefit patient care; particularly in malignancies where treatment resistance is prevalent. Herein, a robust, easy to use, tumour-on-a-chip platform which maintains precision cut head and neck cancer for the purpose of ex vivo irradiation is described. The device utilises sintered discs to separate the biopsy and medium, mimicking in vivo microvascular flow and diffusion, maintaining tissue viability for 68 h. Integrity of tissues is demonstrated by the low levels of lactate dehydrogenase release and retained histology, accompanied by assessment of cell viability by trypan blue exclusion and flow cytometry; fluid dynamic modelling validates culture conditions. An irradiation jig is described for reproducible delivery of clinically-relevant doses (5 × 2 Gy) to newly-presenting primary tumours (n = 12); the addition of concurrent cisplatin is also investigated (n = 8) with response analysed by immunohistochemistry. Fractionated irradiation reduced proliferation (BrdU, p = 0.0064), increased DNA damage (Æ´H2AX, p = 0.0043) and caspase-dependent apoptosis (caspase-cleaved cytokeratin-18) compared to control; caspase-dependent apoptosis was further increased by concurrent cisplatin compared to control (p = 0.0063). This is a proof of principle study showing the response of cancer tissue to irradiation ex vivo in a bespoke system. The novel platform described has the potential to personalise treatment for patients in a cost-effective manner with applicability to any solid tumour.

Star excursion balance test for assessment of dynamic instability of the ankle in patients after harvest of a fibular free flap: a two-centre study.

We aimed to show that the star excursion balance test can identify instability in the ankle of patients who have had harvest of a fibular free flap. We compared the reach distance of the operated leg against that of the non-operated leg in 26 patients who had had harvest of the flap over a period of three years from August 2009 at two different centres. The goal of the test is to reach as far as possible with one leg in eight directions while balancing on the other. We also assessed the overall function of the operated leg using the Foot and Ankle Disability Index (FADI) and the American Orthopaedic Foot and Ankle Score (AOFAS). The star excursion balance test is simple and cheap, and is quick and easy to do in the outpatient department.

Muscle regeneration following repair of the rotator cuff.

AIMS: The aim of this study was to analyse human muscle tissue before and after rotator cuff repair to look for evidence of regeneration, and to characterise the changes seen in the type of muscle fibre. PATIENTS AND METHODS: Patients were assessed pre-operatively and one year post-operatively using the Oxford Shoulder Score (OSS) and MRI. The cross-sectional area and distribution of the type of muscle fibre were assessed on biopsies, which were taken at surgery and one year post-operatively. Paired samples from eight patients were analysed. There were three men and five women with a mean age of 63 years (50 to 73). RESULTS: All but one patient showed improvement in OSS (p = 0.004). The mean increase in the cross-sectional area of the muscle was 1220 µm2 (-801 to 3712; p = 0.03). There was a reduction of type 2a fibres (p = 0.02). A clear relationship could not be seen between the MRI findings and the histological appearances. CONCLUSION: This is the first study to provide evidence that atrophy of the supraspinatus muscle is reversible. Changes in the types of fibre are discussed. MRI assessment of muscle atrophy may not be fully representative of myofibre atrophy. Cite this article: Bone Joint J 2016;98-B:1389-94.

Pinning out pathological specimens--are we risking an unnecessary escalation of treatment?

The importance of surgical resection margins is paramount, and it is vital that they are accurately delineated so that clinicians' decisions about adjuvant treatment can be validated. Pathological specimens therefore are often pinned to aid orientation and maintain mucosal margins. However, in cadaveric resections of bovine tongues, pinning of the specimens significantly reduced the depth of tissue. In clinical practice, if results are affected by the fixation method and not based on the true margins, it could profoundly influence the use of adjuvant treatment in patients with cancer. Pinning the specimens with the mucosal surface against the board will maintain any theoretical benefit for the mucosa and does not compress the specimens.

The use of the pectoralis major flap for advanced and recurrent head and neck malignancy in the medically compromised patient.

A retrospective review of seventy-one PPM flaps used between 1996 and 2010 primarily for oral and oropharyngeal squamous cell carcinoma presenting as either advanced stage IV primary disease (41/43), extensive recurrent (10) or metastatic (9) neck disease. The PPM flap was most commonly used following resection of the mandible (23) or the tongue/oropharynx (19). When the PPM flap was the preferred reconstruction option (54) the main indication, in addition to advanced disease, was significant medical co-morbidity (23). The majority of PPM flaps (75%) were used in the latter half of the series for an increasing number of patients in poor health with advanced disease. There was no evidence of an increase in age, ASA grade or extent of disease during this period. Approximately one quarter (17) of the flaps were used after failure of a free flap, most commonly a DCIA (7) or radial (6) flap. The 30day mortality in this group of compromised patients undergoing major surgery for advanced disease was 7% (5/71). The overwhelming majority had significant co-morbidity (94% grade 2 or higher with 63% ASA grade 3) and 90% had already undergone previous major surgery and/or radiotherapy. The 1-year, 3-year and 5-year overall survival rates were 65.5%, 39.1% and 11.0% respectively with cancer-specific survival rates of 82.0%, 65.5% and 65.5%. The majority died of disease related to the underlying co-morbidity. We recommend an aggressive approach to the surgical resection of advanced and recurrent disease but a pragmatic approach to reconstruction. The PPM major flap is reliable for reconstruction of defects of the mandible, tongue and oropharynx with a complete flap failure rate of 2.8%. Lateral defects of the mandible were managed without a plate and with an acceptable outcome in the context of limited life expectancy. This is the largest study of the use of the PPM flap for this type of patient group. The flap retains a major role in the management of advanced primary or recurrent disease, extensive metastatic neck disease and after failure of a free flap when in conjunction with significant co-morbidity.

The effect of methotrexate-loaded bone cement on local destruction by the VX2 tumour.

Previous studies have shown that the activity of the cytostatic drug methotrexate (MTX) embedded in acrylic cement is not affected by thermal changes in the cement. MTX is slowly released from the cement for several months and remains biologically active throughout this period. Our aim was to determine whether MTX embedded in cement would control the local growth of a tumour. In 15 rabbits we injected 0.1 ml of VX2 tumour suspension into the proximal tibia. At 3, 5, 7, 10 and 14 days three animals were killed and the tibiae removed and examined histologically. With increasing growth of the VX2 carcinoma there was increased bone destruction and a rise in the numbers of osteoclasts, but after 14 days the numbers of osteoclasts had decreased. We then injected VX2 into the tibiae of another 45 rabbits. After 5 days most of the tumour was curetted out and the defect filled with cement containing either 0 g, 0.1 g, 0.5 g, 1.0 g or 2.0 g MTX/40 g cement. The rabbits were divided into three groups and killed at 3, 7 or 10 days after implantation of cement. The number of osteoclasts and the amount of bone destruction were measured in each tibia. In all three groups bone destruction and osteoclast proliferation were markedly decreased with higher doses of MTX, but bone destruction was not eliminated. Our findings show that in the higher doses used, which were not toxic to the animal, MTX-embedded cement may be of value in minimising the amount of tumour-induced osteolysis and may be a useful adjunct in the surgical management of pathological fractures.

Methotrexate loaded acrylic cement in the management of skeletal metastases. Biomechanical, biological, and systemic effect.

Skeletal metastases occur commonly, and frequently are complicated by the development of an impending or pathologic fracture. In the majority of instances, these patients are best treated by internal stabilization, frequently supplemented by methylmethacrylate, to relieve pain and maintain the patient's mobility. The underlying tumor may continue to grow, and if this occurs the progressive lysis may result in loosening and subsequent failure of the implant. To prevent additional local growth, postoperative radiotherapy is recommended, and many patients also receive endocrine or chemotherapy, but the adjuvant therapy is not always successful in preventing progressive local tumor induced osteolysis. It is possible that the addition of chemotherapeutic agents to the methylmethacrylate may inhibit local growth. This study was performed to determine the biomechanical, biologic, and systemic effects of adding methotrexate to methylmethacrylate. The results show that the addition of methotrexate in as much as a concentration of 2 g methotrexate per 40 g cement did not significantly alter the biomechanical characteristics of the bone cement. The incorporated methotrexate was released continuously from the loaded bone cement, and in the amount and concentration used did not have any toxic effects on the host animal. The methotrexate did not appear to be affected by the heat of polymerization and had a significant systemic effect. There was a significant reduction in pulmonary metastases with methotrexate loaded cement as compared with unloaded cement, the effect being dependent on the concentration of methotrexate in the cement. The results of these studies indicate that methotrexate loaded cement may have an important role to play as part of the orthopaedic management of impending and pathologic fractures.

Isolation of a DNA polymerase I (polA) mutant of Rhizobium leguminosarum that has significantly reduced levels of an IncQ-group plasmid.

A population of Tn5 mutagenized Rhizobium leguminosarum cells was screened for mutants affected in protein secretion by introducing a plasmid carrying the Erwinia chrysanthemi prtB gene and screening for mutants defective in secretion of the protease PrtB. One such mutant (A301) also appeared to be defective in secretion of the R. leguminosarum nodulation protein NodO. Genetic analysis showed that the defect in A301 was caused by the Tn5 insertion. However the DNA sequence adjacent to the site of Tn5 insertion had significant homology to the Escherichia coli polA gene, which encodes DNA polymerase I. The mutant A301 showed increased sensitivity to ultraviolet light, a characteristic of polA mutants of E. coli. The apparent defect in secretion by A301 was due to a large decrease in the copy number of the IncQ group replicon on which prtB and nodO were cloned and this decreased the total amounts of PrtB or NodO protein synthesised and secreted by the polA mutant. The polA mutant had a lower growth rate than the parent strain on both rich and minimal media, but there was no obvious effect of the polA mutation on the symbiosis of R. leguminosarum bv. viciae with pea.

The role of an adhesive (Histoacryl) in tendon repair.

Two in vitro experiments have been done comparing various techniques of tendon repair. These include repairs using an adhesive, 2-butyl cyanoacrylate (Histoacryl), and repairs by the modified Kessler technique, using 4/0 braided polyester and 4/0 stainless steel. Mechanical analysis has shown that by replacing the circumferential suture of a modified Kessler tendon repair with Histoacryl, the tensile strength of the repair and the force needed to produce a gap can be increased by 30% to 40%. This improvement was statistically significant (P < 0.05).

The association between alcohol, hepatic pathology and Dupuytren's disease.

We have looked at the incidence of Dupuytren's disease in alcoholics, those with non-alcoholic liver disease and a control population. Both alcoholic patients and those with non-alcohol related liver disease had a higher rate (28% and 22% respectively) than the controls (8%), but this did not quite reach statistical significance (p greater than 0.05). In addition we found no Dupuytren's disease in 50 Egyptian patients with bilharzia and no consistent biochemical abnormalities in 134 patients with significant Dupuytren's disease. We conclude that alcoholics probably do have a higher rate of Dupuytren's disease and that this effect is largely due to the liver disease caused by alcohol abuse, but that the genetic factors are of greater aetiological importance.