The long term effects of uncoupling interventions as a therapy for dementia in humans

In this paper we use simulation methods to study a hypothetical uncoupling agent as a therapy for dementia. We simulate the proliferation of mitochondrial deletion mutants amongst a population of wild-type in human neurons. Mitochondria play a key role in ATP generation. Clonal expansion can lead to the wild-type being overwhelmed by deletions such that a diminished population can no longer fulfil a cell's energy requirement, eventually leading to its demise. The intention of uncoupling is to reduce the formation of deletion mutants by reducing mutation rate. However, a consequence of uncoupling is that the energy production efficacy is also reduced which in turn increases wild-type copy number in order to compensate for the energy deficit. The results of this paper showed that uncoupling reduced the severity of dementia, however, there was some increase in cognitive dysfunction pre-onset of dementia. The effectiveness of uncoupling was dependent upon the timing of intervention relative to the onset of dementia and would necessitate predicting its onset many years in advance.

The prevalence of dementia in humans could be the result of a functional adaptation

In this paper we propose that high copy number of the mitochondrial genome in neurons is a functional adaptation. We simulated the proliferation of deletion mutants of the human mitochondrial genome in a virtual mitochondrion and recorded the cell loss rates due to deletions overwhelming the wild-type. Our results showed that cell loss increased with mtDNA copy number. Given that neuron loss equates to cognitive dysfunction, it would seem counterintuitive that there would be a selective pressure for high copy number over low. However, for a low copy number, the onset of cognitive decline, while mild, started early in life. Whereas, for high copy number, it did not start until middle age but progressed rapidly. There could have been an advantage to high copy number in the brain if it delayed the onset of cognitive decline until after reproductive age. The prevalence of dementia in our aged population is a consequence of this functional adaptation.

Isolated lesions of the pubis

The osseous pelvis is a well-known area of various primary and secondary bone tumours, tumour mimics, and infections. Isolated lesions of the pubis (ILP) are rare, with few case reports in the literature. Given their sparsity, such lesions may pose a great diagnostic challenge due to varied clinical presentations and imaging features. In this study, we report the largest case series of ILP. We discuss the patient demographics, differentials, surgical approaches, and management.

609 Metachronous Osteoid Osteoma of the Mid-Diaphysis of the Fibula and Distal Humerus: A Case Report

A 7-year-old boy presented with a 4-week history of pain and swelling of the right leg. He had a history of mucoepidermoid carcinoma of the parotid gland, treated by surgical resection without any complication. There was no other significant past medical history. A radiograph of the right leg showed a lytic lesion of the right diaphysis of the fibula with periosteal reaction. An MRI of the right leg showed osteoid osteoma of the fibula with marked cortical thickening with osseous and soft tissue oedema. The patient subsequently had a Jamshidi biopsy and curettage of the lesion, with the histopathological results of the biopsy showing fragments of a typical osteoid osteoma nidus with irregular calcified bony lamellae. His symptoms had significantly improved after the procedure, and he was ambulating without any discomfort or pain. The patient remained asymptomatic until he returned seven years later with right elbow swelling, pain and reduced range of movement over 2–3 months. A radiograph of the elbow joint had shown a large effusion with a sclerotic lesion on the coronoid fossa of the distal humerus in keeping with an osteoid osteoma. The patient had a confirmational biopsy and subsequently radiofrequency ablation of the lesion with complete resolution of pain. To our knowledge, our case is an atypical presentation of osteoid osteoma in two widely separate bones, between the lower and the upper limb separated by seven years disease-free interval.

A comparison of mtDNA deletion mutant proliferation mechanisms

In this paper we use simulation methods to investigate the proliferation of deletion mutations of mitochondrial DNA in neurons. We simulate three mtDNA proliferation mechanisms, namely, random drift, replicative advantage and vicious cycle. For each mechanism, we investigated the effect mutation rates have on neuron loss within a human host. We also compare heteroplasmy of each mechanism at mutation rates that yield the levels neuron loss that would be associated with dementia. Both random drift and vicious cycle predicted high levels of heteroplasmy, while replicative advantage showed a small number of dominant clones with a low background of heteroplasmy.

The Effect of Mitochondrial DNA Half-Life on Deletion Mutation Proliferation in Long Lived Cells

The proliferation of mitochondrial DNA (mtDNA) with deletion mutations has been linked to aging and age related neurodegenerative conditions. In this study we model the effect of mtDNA half-life on mtDNA competition and selection. It has been proposed that mutation deletions ([Formula: see text]) have a replicative advantage over wild-type ([Formula: see text]) and that this is detrimental to the host cell, especially in post-mitotic cells. An individual cell can be viewed as forming a closed ecosystem containing a large population of independently replicating mtDNA. Within this enclosed environment a selfishly replicating [Formula: see text] would compete with the [Formula: see text] for space and resources to the detriment of the host cell. In this paper, we use a computer simulation to model cell survival in an environment where [Formula: see text] compete with [Formula: see text] such that the cell expires upon [Formula: see text] extinction. We focus on the survival time for long lived post-mitotic cells, such as neurons. We confirm previous observations that [Formula: see text] do have a replicative advantage over [Formula: see text]. As expected, cell survival times diminished with increased mutation probabilities, however, the relationship between survival time and mutation rate was non-linear, that is, a ten-fold increase in mutation probability only halved the survival time. The results of our model also showed that a modest increase in half-life had a profound affect on extending cell survival time, thereby, mitigating the replicative advantage of [Formula: see text]. Given the relevance of mitochondrial dysfunction to various neurodegenerative conditions, we propose that therapies to increase mtDNA half-life could significantly delay their onset.

Prevalence of Enchondromas of the Proximal Femur in Adults as an Incidental Finding on MRI of the Pelvis

Objective  To determine the prevalence of enchondroma in adults as an incidental finding in the proximal femur on magnetic resonance imaging (MRI). Materials and Methods  A retrospective review of the MRI scans of the pelvis in a series of adult patients was conducted. All presented with nononcological musculoskeletal complaints. The site, size, and appearances of the enchondromas were identified according to criteria from previous studies. Results  A total of 1,209 proximal femora in 610 patients were reviewed and a total of 9 enchondromas were identified. These ranged from 0.6 to 2.5 cm in length (mean 1.3 cm). None showed aggressive features suggestive of malignancy. Three cases (33%) underwent follow-up MRI scans which showed no change in size or morphology. Conclusion  The prevalence on MRI of incidental enchondromas arising in the proximal femur is 0.7%. This is three to four times less common than seen in the proximal humerus and around the knee.

Psoas muscle atrophy following unilateral hip arthroplasty

BACKGROUND

Studies have demonstrated the presence of muscle atrophy around the hip in patients with hip osteoarthritis. Few studies have examined the psoas muscle or assessed it at a paraspinal level in patients post-total hip arthroplasty. The aim of this study was to determine if there is significant psoas muscle atrophy as indicated by muscle cross-sectional area and high degree of fat infiltration post-unilateral hip arthroplasty.

METHODS

Retrospective analysis of 341 patients with unilateral hip implant and subsequent lumbar spine MRI over a 8-year period was performed. Fat infiltration and cross-sectional area of the psoas muscle at L3/4 level were measured by two musculoskeletal fellows (1 year experience in musculoskeletal radiology), and comparison made between the implant and non-operative sides was made. Fat infiltration was measured using the modified Goutallier grading. The degree of hip osteoarthritis in the non-operative side was measured using the Kellgren-Lawrence grading. The data was analysed using paired t test, ANOVA, unpaired t test, Pearson correlation and Jonckheere-Terpstra test.

RESULTS

The cross-sectional area of the psoas muscle on the implant side was significantly less than the non-operative side. There was significance between the cross-sectional area difference and the fat grade of the implant side.

CONCLUSION

Our results demonstrate psoas atrophy on the implant side compared to the non-operative side in post-unilateral implant patients. Post-operative hip implant rehabilitation may benefit from more focused psoas strengthening exercises to improve functional outcome.

MRI assessment of anatomy and pathology of the iliofemoral ligament

The iliofemoral ligament is strongest ligament of the body. We review the magnetic resonance imaging (MRI) appearances of the iliofemoral ligament, and discuss the disease entities that may affect this region.

An imaging protocol for the management of central cartilage tumours of the proximal fibula

AIM

To retrospectively review a series of solitary central cartilage tumours (CCTs) of the proximal fibula and propose an imaging protocol for their management.

MATERIALS AND METHODS

Over 11 years, 48 patients were identified with a CCT of the proximal fibula. The initial magnetic resonance imaging (MRI) and follow-up imaging were assessed for tumour length, endosteal scalloping, or aggressive/malignant features. Each case was categorised according to the Birmingham Atypical Cartilage Tumour Imaging Protocol (BACTIP). The final diagnosis and outcome were reviewed to establish an appropriate imaging protocol for the management of similar cases in the future.

RESULTS

The final diagnosis based on imaging alone or imaging and histopathology was enchondroma in 46 cases (96%) and atypical cartilage tumour (ACT)/low-grade chondrosarcoma in two (4%). Using the BACTIP classification, the majority were type IC (48%) with type IA the second commonest (24%). Of 19 that underwent follow-up MRI, only two revealed any increase in length, neither of which was shown to be malignant. No cases re-presented later with evidence of malignant transformation.

CONCLUSION

There has been a significant increase in the number of CCTs of the proximal fibula referred to Royal Orthopaedic Hospital, Birmingham, over the past decade. This can largely be attributed to the increased use of MRI. The majority were benign with only 4% classified as an ACT. A modified BACTIP, the Fibular Atypical Cartilage Tumour Imaging Protocol (FACTIP) is presented, indicating which cases would benefit from follow-up imaging and which require referral to a specialist orthopaedic oncology service.

Computer assisted tumour surgery - An insight

Success in the management of bone sarcomas entails being able to achieve wide margins, which helps decrease the risk of local recurrence and provide an improvement in overall survival. The role of computer-assisted surgery has been investigated across various areas of orthopaedics, including joint replacement, cruciate ligament reconstruction, and pedicle screw placements which has led to increased interested in computer assisted tumour surgery (CATS). CATS can be used in a wide array of tumour surgeries, however its role in pelvic and sacral tumours is unparalled. Its importance lies in being able to provide radiological information to guide the surgeon at the time of surgery i.e. the distance from the tumour to the resection margin can be determined precisely based on preoperative planning and intra-operative image guidance. This minimises unnecessary bone resection, aiming to achieve good oncological and functional results which can be challenging in pelvic surgery. Most published articles on CATS have concentrated on the surgical aspects of navigation surgery. Although advanced imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) scans can provide anatomic detail about the primary tumour, the successful transfer of that information from a viewing screen to the intraoperative field can be difficult. The role of the radiologist lies in being able to provide appropriate imaging (CT, MRI) to facilitate surgical planning. This article aims at providing the radiologist a surgical insight on CATS and to facilitate optimal imaging in a patient tentatively being planned for CATS.

Osteochondroma-induced pseudoaneurysms of the extremities mimicking sarcoma: a report of seven contemporary and one historical case

AIM

To provide a diagnostic approach to distinguish osteochondroma-induced pseudoaneurysm from sarcoma on imaging and prevent biopsy which may be fatal.

MATERIALS AND METHODS

A retrospective study of the orthopaedic oncology database was performed to identify all patients referred to specialist orthopaedic oncology service with a final diagnosis of osteochondroma-induced pseudoaneurysm. The demographics of the cohort, the anatomical location of the osteochondromas and pseudoaneurysms, and the imaging appearances were assessed.

RESULTS

Seven contemporary and one historical case of osteochondroma-induced-pseudoaneurysm were identified. There were five patients with solitary osteochondroma and three cases of hereditary multiple exostosis. Five cases underwent magnetic resonance imaging (MRI) of which pulsation artefact was present in 40%. On MRI, all the present cases demonstrated a small central pseudoaneurysm surrounded by multiple eccentric layers of thrombus and haemorrhage, which was termed the "eccentric-whorl sign".

CONCLUSION

Osteochondroma-induced pseudoaneurysms are often misdiagnosed as malignant transformation of an osteochondroma or a soft-tissue sarcoma and referred for urgent biopsy. This study presents the largest case series, which includes the first documented case diagnosed in 1934. Differentiating and characterising pseudoaneurysms from sarcomas is imperative in order to prevent a biopsy, which could be fatal.

Are the tubular bones of the hand really the commonest site for an enchondroma?

AIM

To investigate whether the long-held view that the hand is the commonest site for an enchondroma is actually correct in light of more sensitive imaging techniques that are able to demonstrate small enchondromas at other skeletal sites.

MATERIALS AND METHODS

A two-part retrospective study was undertaken. Part 1 comprised a review of the hand radiographs obtained in two major teaching hospitals over a 10-year period to establish the incidence of enchondroma in the hand. Part 2 was a review of a series of enchondromas of the proximal humerus, distal femur, and proximal tibia <4 cm in length on magnetic resonance imaging (MRI) to see which cases were visible or not on corresponding radiographs.

RESULTS

Part 1: 84 enchondromas were identified on 116,354 trauma radiographs to give an incidence of 0.07%. Part 2: 157 patients with an enchondroma on MRI <4 cm were reviewed. Only 17% of lesions <2 cm in length were visible on the contemporaneous radiographs. In lesions that were 2-2.9 and 3-3.9 cm the percentage visible on the radiographs increased to 58 and 77%, respectively.

CONCLUSION

It is well recognised from existing studies that incidental enchondromas can be seen in approximately 2.5% of routine shoulder and knee MRI scans. This figure is 35 times higher than the incidence found in the series of hand trauma radiographs. This infers that the hand should no longer be considered as the commonest site for an enchondroma. This is because radiographs are relatively insensitive to the detection of small lesions in larger bones, such as the proximal humerus and around the knee, when compared with MRI.

The diagnostic significance of pulmonary nodules on CT thorax in chondrosarcoma of bone

AIM

To provide a diagnostic approach to pulmonary nodules in patients with chondrosarcoma.

MATERIALS AND METHODS

A search of the oncology database at a specialist orthopaedic oncology referral centre was performed to identify all patients who were treated surgically for chondrosarcoma between January 2007 and December 2018. Reports from the computed tomography (CT) examinations of the thorax of these patients were reviewed. In patients who had pulmonary nodules/metastases identified on CT, data on the primary chondrosarcoma and pulmonary nodule characteristics were collected.

RESULTS

Twenty point two percent of patients had a pulmonary nodule identified on either initial or follow-up staging CT of the thorax, of which 8.1% were pulmonary metastases. Patients with grade 3 and dedifferentiated chondrosarcoma were more likely to have pulmonary metastases than patients with grade 1/2 chondrosarcoma. The time interval to developing metastases was shorter in patients with grade 2/3 and dedifferentiated chondrosarcoma versus patients with grade 1 chondrosarcoma. A low proportion of patients with grade 1 chondrosarcoma developed metastases (12.5%), all of which were identified at the time of a local recurrence. Nodules ≥10mm, nodules with lobulate margins, nodules containing irregular or subtle calcification, and nodules seen bilaterally or both centrally and peripherally were more likely to represent pulmonary metastases than benign nodules.

CONCLUSION

The diagnostic significance of pulmonary nodules (i.e., whether they represent pulmonary metastases or not) can be predicted by taking into account a number of factors, in particular, the histological grade of the patient's chondrosarcoma, the size and margins of the nodules, and the presence of subtle/irregular calcification.

"Flow-void" sign in osseous metastatic renal cell carcinoma

AIM

To evaluate the frequency of the "flow-void" sign in a large series of pathologically proven renal cell carcinoma (RCC) bone metastases referred to a specialist unit and to evaluate its correlation with both lesion size and imaging sequence. A further aim was to describe a proposed grading system for the description of the "flow-void" sign.

MATERIALS AND METHODS

A retrospective review of patients with magnetic resonance imaging (MRI) of pathologically proven RCC bone metastases between September 2007 and December 2017 was performed. MRI images were reviewed for the presence of the "flow-void" sign and a proposed grading system for this sign was applied. Statistical analysis was performed to determine the association between the presence of the "flow-void" sign and lesion size and MRI sequence.

RESULTS

One hundred and forty bone lesions in 123 patients with histologically proven metastatic RCC were reviewed. One hundred and thirty-two (94.3%) lesions demonstrated the "flow-void" sign on at least one sequence in each study. A statistically significant difference was demonstrated between lesion size and the presence and type of "flow-void" sign. Lesions demonstrating type 3 "flow-void" sign had mean dimensions of 82.2 mm compared to 47.3 mm for lesions that did not demonstrate the "flow-void" sign (χ²(2) =11.4; p=0.01). T2-weighted, proton density and fat-saturated imaging also demonstrated the "flow-void" sign more frequently.

CONCLUSION

The "flow-void" sign is a common imaging feature within RCC bone metastases. When observed, the "flow-void" sign can be a useful imaging feature in the diagnosis of RCC bone metastases.

Correction to: Current concept in upright spinal MRI

Unfortunately, the legend of Fig. 5 was incorrectly published in original publication. The corrected legend is given below.

A diagnostic approach to popliteal fossa masses

There is a myriad of potential mass lesions that occur in the popliteal fossa, which present as palpable masses or are found incidentally on imaging. With a thorough knowledge and understanding of the appearances and locations of these different entities, one can narrow the differential diagnoses in the majority of cases. This will eliminate unnecessary additional investigations and enable a more rapid management. We present a review of frequently encountered and less common entities using an anatomical sieve, with the aim of providing a diagnostic approach to popliteal fossa masses.

Chemical shift MRI can aid in the diagnosis of indeterminate skeletal lesions of the spine

OBJECTIVES

To evaluate the role of chemical shift MRI in the characterisation of indeterminate skeletal lesions of the spine as benign or malignant.

METHODS

Fifty-five patients (mean age 54.7 years) with 57 indeterminate skeletal lesions of the spine were included in this retrospective study. In addition to conventional MRI at 3 T which included at least sagittal T1WI and T2WI/STIR sequences, patients underwent chemical shift MRI. A cut-off value with a signal drop-out of 20 % was used to differentiate benign lesions from malignant lesions (signal drop-out <20 % being malignant).

RESULTS

There were 45 benign lesions and 12 malignant lesions. Chemical shift imaging correctly diagnosed 33 of 45 lesions as benign and 11 of 12 lesions as malignant. In contrast, there were 12 false positive cases and 1 false negative case based on chemical shift MRI. This yielded a sensitivity of 91.7 %, a specificity of 73.3 %, a negative predictive value of 97.1 %, a positive predictive value of 47.8 % and a diagnostic accuracy of 82.5 %.

CONCLUSIONS

Chemical shift MRI can aid in the characterisation of indeterminate skeletal lesions of the spine in view of its high sensitivity in diagnosing malignant lesions. Chemical shift MRI can potentially avoid biopsy in a considerable percentage of patients with benign skeletal lesions of the spine.

KEY POINTS

• Differentiating benign from malignant skeletal lesions of the spine can be challenging. • Utility of chemical shift MRI in characterising indeterminate spinal lesion is unreported. • This study demonstrates sensitivity 91.7 %, specificity 73.3 %, diagnostic accuracy 82.5 % for CSI. • CSI is useful in differentiating benign from malignant skeletal spine lesions. • Biopsy can potentially be avoided in some patients with benign skeletal lesions.

Imaging of extremity soft tissue masses: pitfalls in diagnosis

Soft tissue sarcomas are rare tumours which can be clinically difficult to differentiate from more common benign lesions. Imaging plays a fundamental role in diagnosis, but in some cases it can be difficult to differentiate benign from malignant conditions. This article reviews potential pitfalls in soft tissue sarcoma imaging.

Human IgE against the major allergen Bet v 1--defining an epitope with limited cross-reactivity between different PR-10 family proteins

Background

The interaction between IgE and allergen is a key event at the initiation of an allergic response, and its characteristics have substantial effects on the clinical manifestation. Despite this, the molecular details of the interaction between human IgE and the major birch allergen Bet v 1, one of the most potent tree allergens, still remain poorly investigated.

Objective

To isolate Bet v 1-specific human monoclonal IgE and characterize their interaction with the allergen.

Methods

Recombinant human IgE were isolated from a combinatorial antibody fragment library and their interaction with Bet v 1 assessed using various immunological assays. The structure of one such IgE in the single-chain fragment variable format was determined using X-ray crystallography.

Results

We present four novel Bet v 1-specific IgE, for one of which we solve the structure, all with their genetic origin in the IGHV5 germline gene, and demonstrate that they target two non-overlapping epitopes on the surface of Bet v 1, thereby fulfilling the basic criteria for FcεRI cross-linkage. We further define these epitopes and for one epitope pinpoint single amino acid residues important for the interaction with human IgE. This provides a potential explanation, at the molecular level, for the differences in recognition of isoforms of Bet v 1 and other allergens in the PR-10 protein family displayed by IgE targeting this epitope. Finally, we present the first high-resolution structure of a human allergen-specific IgE fragment in the single-chain fragment variable (scFv) format.

Conclusions and Clinical Relevance

We here display the usefulness of allergen-specific human monoclonal IgE as a tool in studies of the crucial molecular interaction taking place at the initiation of an allergic response. Such studies may aid us in development of better diagnostic tools and guide us in the development of new therapeutic compounds.

Post-traumatic heterotopic ossification of distal tibiofibular syndesmosis mimicking a surface osteosarcoma

AIM

To present the imaging features of post-traumatic heterotopic ossification (HO) of the distal tibiofibular syndesmosis initially suspected to be a surface osteosarcoma.

MATERIALS AND METHODS

A retrospective review was conducted of the presenting complaint and imaging features of patients with a final diagnosis of HO referred over an 8 year period to a specialist orthopaedic oncology centre.

RESULTS

Five patients with HO were identified. All were adult males with an age range of 19-41 years. There was a history of prior ankle trauma in all cases but the significance was not recognized at the time of referral to the specialist centre. There was radiographic evidence of HO arising from the inner aspects of the distal tibia and fibula approximately 3 cm proximal to the ankle joint. The HO was "kissing" in two cases and partially fused (synostosis) in two. The HO in the fifth case was arising on the inner fibular cortex alone. Magnetic resonance imaging (MRI), available in four cases, showed predominantly low signal intensity due to the dense bone formation.

CONCLUSION

The history of prior ankle trauma with ossification arising from the inner aspects of both the distal tibia and fibula is typical of post-traumatic HO and distinguish this benign condition from the rare surface osteosarcoma at this site.

Can MR imaging challenge the commonly accepted theory of the pathogenesis of solitary enchondroma of long bone?

OBJECTIVE

It has been widely postulated that enchondromas arise from cartilage remnants that have been displaced from the growth plate into the metaphysis. However, this theory remains unproven. Based on the common occurrence of enchondromas on routine knee MR imaging (2.9 %), one would expect to find displaced cartilage in the metaphysis of skeletally immature individuals on routine knee MR examinations if the above theory was to be supported.

MATERIALS AND METHODS

The electronic databases of a specialist orthopedic hospital and children's hospital were searched for skeletally immature patients who underwent MR imaging of the knee for a variety of indications. Individuals with Ollier disease or hereditary multiple exostoses were excluded. The MR images were subsequently reviewed by a musculoskeletal radiologist for evidence of displaced cartilage into the metaphysis.

RESULTS

We reviewed 240 MR examinations of the knee that were performed in 209 patients. There were 125 MR studies in male and 115 MR examinations in female patients (age range: 5 months-16 years; median age: 13 years). In 97.1 %, the growth plates around the knee demonstrated a regular appearance. Seven cases (2.9 %) in six patients showed cartilage extension from the growth plate into the metaphysis, which remained in continuity with the growth plate. There were no cases of displaced cartilage into the metaphysis on MRI.

CONCLUSIONS

Our study challenges the widely believed theory that enchondromas arise from displaced growth plate remnants.

Profunda femoris pseudoaneurysm following Birmingham hip resurfacing: an important differential diagnosis for a periarticular cystic mass

Vascular injury following hip resurfacing arthroplasty is rare: we present a case of profunda femoris pseudoaneurysm complicating hip resurfacing arthroplasty performed via an anterolateral approach. Over recent years, it has been recognized that an adverse reaction to metal debris from metal-on-metal arthroplasties can also result in the development of cystic masses around the hip. This case highlights a potential rare differential diagnosis that needs to be considered when imaging cystic mass lesions around the postoperative hip. Imaging can provide a definitive diagnosis if this entity is considered and its appearances recognized, resulting in appropriate management of this potentially limb- and life-threatening complication.

Phase I study of continuous and intermittent schedules of lapatinib in combination with vinorelbine in solid tumors

BACKGROUND

Chemotherapy in combination with small-molecule epidermal growth factor receptor inhibitors has yielded inconsistent results. Based on preclinical models, we conducted a phase I trial of two schedules of lapatinib and vinorelbine.

PATIENT AND METHODS

Patients had advanced solid tumors and up to two prior chemotherapeutic regimens. Patients were enrolled on two dose-escalating schedules of lapatinib, continuous (arm A) or intermittent (arm B), with vinorelbine on days 1, 8, and 15 of a 28-day cycle. Tumors from a subset of patients were evaluated for gene mutations and expression of targets of interest.

RESULTS

Fifty-one patients were treated. The most common grade 3/4 toxic effects included leukopenia, neutropenia, and fatigue. Dose-limiting toxic effects were grade 3 infection, febrile neutropenia, and diarrhea (arm A) and bone pain and fatigue (arm B). The maximum tolerated dose was vinorelbine 20 mg/m(2) weekly and lapatinib 1500 mg daily (arm A) and vinorelbine 25 mg/m(2) weekly and lapatinib 1500 mg intermittently (arm B). One patient on each arm had a complete response; both had human epidermal growth factor receptor 2-positive breast cancer. In a subset of patients, lack of tumor PTEN expression correlated with a shorter time to progression.

CONCLUSION

In an unselected population, two schedules of lapatinib and vinorelbine were feasible and well tolerated.

Longitudinal growth following treatment for osteosarcoma

Purpose. The purpose of this study was to analyse the height at diagnosis and growth in 72 skeletally immature children who had been treated for osteosarcoma in the area of the knee.

Subjects. Of the patients, the average age at diagnosis was 10 years in girls and 12 years in boys. All children received neo-adjuvant chemotherapy, and had limb salvage by endoprosthetic replacement.

Results and conclusion. The results of this study indicate that there is no evidence that children with osteosarcoma are taller at diagnosis than their normal counterparts. However, there was a marked retardation in growth in the year following the administration of cytotoxic chemotherapy. There were 19 children who reached skeletal maturity. The final height in these children was not significantly different from the normal population.

Clear cell chondrosarcoma in association with niemann-pick disease

Purpose: The purpose of this case report is to bring to light this unusual combination of two rare diseases, namely Neimann-Pick disease Type B and clear cell chondrosarcoma occurring in the same patient. This has not previously been reported in the world literature.

Subject: Niemann-Pick disease (NPD) is a rare autosomal recessive inborn error of metabolism. Type B NPD is even rarer. It is a lysosomal storage disorder affecting children and adolescents often causing death in early childhood, although in milder form patients may survive up to adulthood, like our patient. Clear cell chondrosarcoma is a very rare type of chondrosarcoma affecting the epiphyseo-metaphyseal region of long bones. We present a patient suffering from a milder form of Neimann Pick disease who developed a clear cell chondrosarcoma. We investigated to find if there was likely to be any relationship between these two events.

Results: NPD type B is caused by a three-base deletion in chromosome 11. Chondrosarcoma and multiple exostoses occur due to loss of tumour suppressor gene EXT 2 from centromeric region on chromosome 11, though it is difficult to establish the link between the two, as the two together have not yet been reported in the literature. NPD may present diagnostic difficulties when it occurs with chondrosarcoma.

Discussion: We conclude that the two diseases have not been reported together in the world literature and there is some evidence to show that chromosome 11 is central to both diseases. More research is needed to see if one leads to the other.

Clear cell chondrosarcoma of bone

Purpose. Clear cell chondrosarcoma is a rare variant of chondrosarcoma. Six cases are herein reported.

Subjects. We have treated six patients with clear cell chondrosarcoma in the past 28 years, representing 1.6% of all chondrosarcomas seen in this time period.

Results and Discussion. Half the patients had been initially underdiagnosed and inappropriately treated.

Conclusions. Our results and our review of the literature highlight the fact that inadequate initial treatment leads to a high rate of both local recurrence and metastasis whilst wide initial excision is usually curative.

Malignant chondroblastoma of the os calcis

Patient. We describe a case of chondroblastoma of the os calcis which metastasized to the tibia, soft tissues and lung. A complete response of the lung lesions was noted with chemotherapy.

Discussion. Review of the published literature shows that metastatic chondroblastoma only arises following local recurrence of the tumour.

Metabolism and pharmacokinetics of naronapride (ATI-7505), a serotonin 5-HT(4) receptor agonist for gastrointestinal motility disorders

The absorption and disposition of the serotonin 5-HT(4) receptor agonist, naronapride (6-[(3S,4R)-4-(4-amino-5-chloro-2-methoxy-benzoylamino)-3-methoxy-piperidin-1-yl]-hexanoic acid 1-aza-bicyclo[2,2,2]oct-(R)-3-yl ester dihydrochloride; ATI-7505), were evaluated in healthy males given a single 120-mg oral dose of (14)C-labeled compound. Serial blood samples and complete urine and feces were collected up to 552 h postdose. Naronapride was extensively metabolized, undergoing rapid hydrolysis to 6-[(3S,4R)-4-(4-amino-5-chloro-2-methoxy-benzoylamino)-3-methoxy-piperidin-1-yl]-hexanoic acid (ATI-7500) with stoichiometric loss of quinuclidinol. ATI-7500 was either N-glucuronidated on the phenyl ring or its hexanoic acid side chain underwent two-carbon cleavage, probably through a β-oxidation metabolic pathway, to form 4-[(3S,4R)-4-(4-amino-5-chloro-2-methoxy-benzoylamino)-3-methoxy-piperidin-1-yl]-butanoic acid (ATI-7400). ATI-7400 underwent further side-chain oxidation to form 2-[(3S,4R)-4-(4-amino-5-chloro-2-methoxy-benzoylamino)-3-methoxy-piperidin-1-yl]-acetic acid (ATI-7100). Quinuclidinol, ATI-7500, ATI-7400, and ATI-7100 were the major metabolites, with plasma area under the curve values approximately 72-, 17-, 8-, and 2.6-fold that of naronapride. Naronapride, ATI-7500, ATI-7400, and ATI-7100 accounted for 32.32, 36.56, 16.28, and 1.58%, respectively, of the dose recovered in urine and feces. ATI-7400 was the most abundant radioactive urinary metabolite (7.77%), and ATI-7500 was the most abundant metabolite in feces (35.62%). Fecal excretion was the major route of elimination. Approximately 32% of the dose was excreted unchanged in feces. Naronapride, ATI-7500, and quinuclidinol reached peak plasma levels within 1 h postdose. Peak ATI-7400 and ATI-7100 concentrations were reached within 1.7 h, suggesting rapid ATI-7500 metabolism. Naronapride plasma terminal half-life was 5.36 h, and half-lives of the major metabolites ranged from 17.69 to 33.03 h. Naronapride plasma protein binding was 30 to 40%. The mean blood/plasma radioactivity ratio indicated minimal partitioning of (14)C into red blood cells.

Magnetic resonance imaging appearances following hindquarter amputation for pelvic musculoskeletal malignancy

OBJECTIVE

To describe our experience of the magnetic resonance imaging (MRI) appearances after hindquarter amputation, focusing on the normal pattern of time-related changes in signal intensity within the amputation flap and appearances of local disease recurrence.

MATERIALS AND METHODS

This was a retrospective review of the records of patients identified on our orthopaedic oncology database who had undergone hindquarter amputation at our centre. Examinations were divided into one group consisting of 'normal' postoperative findings and another group demonstrating local recurrence. 'Normal' postoperative findings were assessed for signal intensity, morphology and presence of the 'muscle texture sign' within the amputation flap. Examinations were grouped according to time from surgery. Examinations demonstrating local recurrence were assessed for site, signal intensity, morphology and axial dimensions of recurrent tumour. Comparison was made to pre-operative imaging.

RESULTS

Thirty-five patients with postoperative MR images were identified. Seventy-seven examinations were reviewed (range 1-18 per patient). The 'normal group' comprised 18 patients (seven female, 11 male, mean age 44 years, range 16-75 years), with 47 examinations reviewed. The 'muscle texture sign' was preserved in all examinations in this group. Up to 6 months after surgery, 100% (10) of examinations showed hyperintense T2- and short-tau inversion recovery (STIR-weighted) signals within the muscle flap, indicating oedema. Only after 4 years was the muscle flap signal isointense in all cases (13). Up to 6 months after surgery, 50% (5 of 10) of examinations demonstrated flap swelling, but after 1 year, 100% (28) showed atrophy. Twenty percent (2 of 10) of examinations 0-6 months from surgery showed hyperintense T1-weighted signal within the muscle flap, consistent with fatty infiltration, but after 2 years, 100% (20) showed a hyperintense T1-weighted signal. The 'local recurrence' group comprised 20 patients (six female, 14 male, mean age 45.7 years, range 14-69 years), with 30 examinations demonstrating recurrent disease or metastasis. There were 23 recurrent tumours, of which 43% (10) were in the muscle component of the amputation flap, 13% (3 of 23) were in subcutaneous tissues of the flap, 13% (3 of 23) were at the posterior margin of the bone resection and 13% (3 of 23) were paraspinal. All recurrent tumours demonstrated hyperintense T2 and STIR signals. The signal intensity pattern of recurrence closely followed that of the original tumour. The 'muscle texture sign' was absent in all examinations demonstrating recurrence in muscle flap.

CONCLUSION

A pattern of time-related signal intensity and morphological changes is observed within normal hindquarter amputation flaps on MRI. Recurrent disease is most likely to occur within the muscle flap, typically of high T2-weighted signal intensity and characteristically follows the signal pattern of the original tumour.

Hip arthroplasty. Part 2: normal and abnormal radiographic findings

This review addresses the normal and abnormal radiographic findings that can be encountered during the follow-up of patients with total hip arthroplasty (THA). The relative significance of different patterns of radiolucency, bone sclerosis, and component position is discussed. The normal or pathological significance of these findings is correlated with design, surface, and fixation of the prosthetic components. It is essential to have a good knowledge of expected and unexpected radiological evolution according to the different types of prostheses. This paper emphasizes the importance of serial studies compared with early postoperative radiographs during follow-up in order to report accurately any sign of prosthetic failure and trigger prompt specialist referral. Basic technical guidelines and schedule recommendations for radiological follow-up are summarized.

Giant cell tumour of the triquetrum

We present details of a case of giant cell tumour of bone (GCTOB) involving the triquetrum. GCTOB arising within the carpus is exceedingly rare and, to our knowledge, this is only the second case of monostotic GCTOB of the triquetrum that has been reported.

Tumour and tumour-like lesions of the intercondylar notch of the knee: a pictorial review

A variety of tumours and tumour-like lesions are found in the intercondylar notch of the knee. MR imaging is the technique of choice in evaluating these conditions. Correlation with radiographs is important to identify those lesions containing calcification. This review article discusses the imaging features of tumour and tumour-like lesions involving the intercondylar notch with an emphasis on MR imaging features that suggest a specific diagnosis.

Does the presence of focal normal marrow fat signal within a tumor on MRI exclude malignancy? An analysis of 184 histologically proven tumors of the pelvic and appendicular skeleton

OBJECTIVE

The aim of this study was to determine if the presence of focal normal bone marrow fat signal within a tumor on magnetic resonance imaging excludes malignancy.

MATERIALS AND METHODS

One hundred eighty-four histologically proven tumors with available magnetic resonance imaging (MRI) of the appendicular skeleton and pelvis from 184 patients were collected and reviewed at two separate institutions. There were 111 malignant and 73 benign tumors. Two radiologists at each institution, blinded to the diagnosis, reviewed the MRIs independently and reported the presence or absence of normal marrow fat signal within the tumor based upon T1-weighted imaging without fat suppression and T2-weighted imaging with fat suppression and/or short inversion-time inversion recovery (STIR). Discrepancies were then reviewed in consensus to determine the presence or absence of focal normal marrow signal. For each institution, a Fisher's exact test was used to compare the frequency of focal normal marrow fat signal in benign and malignant tumors. This comparison was performed for each reader, as well as for the consensus reading at each site. Positive and negative predictive values were also calculated for each reader, as well as the consensus reading at each site. Fisher's exact test was also used to compare the frequency of intratumoral fat in benign and malignant lesions for the pooled sample. Bayes theorem was used to calculate the positive and negative predictive values for the pooled consensus data. Ninety-five percent confidence intervals were constructed for the pooled estimates using a bootstrapping algorithm.

RESULTS

There was good interobserver reliability of 95.3% and 96.7% at sites 1 and 2, respectively. There were three discrepancies (one malignant and two benign) at site 1 and four discrepancies (two malignant and two benign) at site 2. Reader consensus at site 1 identified normal marrow fat signal within 1 of 50 (2.0%) malignant and three of 14 (21.4%) benign tumors. Findings were statistically significant with a p value of 0.030. The positive predictive value (PPV) and negative predictive value (NPV) at site 1 was 81.7% and 75.0%, respectively. Reader consensus at site 2 identified normal marrow fat signal within three of 61 (4.9%) malignant and 14 of 59 (23.7%) benign tumors. Findings were statistically significant with a calculated p value of 0.004. The PPV and NPV at site 1 was 56.3% and 82.4%, respectively. For the pooled consensus, the frequency of intratumoral fat in benign lesions (17/73, 23.3%) is significantly greater than the frequency in malignant lesions (4/111, 3.6%), p < 0.001.

CONCLUSION

The presence of focal normal marrow signal within a tumor is highly suggestive of a benign tumor.

Imaging strategy for detecting lung metastases at presentation in patients with soft tissue sarcomas

PURPOSE

To identify the risk of lung metastases at the time of diagnosis in patients with soft tissue sarcomas (STS) and to establish the optimum imaging strategy for the diagnosis of these metastases and whether this affects outcome.

MATERIALS AND METHODS

A retrospective review of an orthopaedic oncology database identified 1170 patients with newly diagnosed STS during a 7.5-year period (1996-2004). The patient demographics, tumour type, size, depth, histology grade and presence of metastatic disease at presentation were studied. The chest radiograph (CXR)/computed tomography of the chest (CT chest) findings, performed as part of the initial staging study, were available in all patients. We estimated the efficacy of CXR in identifying pulmonary metastatic disease compared with CT chest and whether this affected patient survival.

RESULTS

The incidence of metastases at diagnosis was 10% (116 patients), 8.3% (96 patients) had lung metastases on chest CT and 1.7% (20 patients) had metastases elsewhere. The risk of having lung metastases at diagnosis was 11.8% in high grade tumours, 7% in intermediate grade and 1.2% in low grade tumours. CXR alone detected 2/3 of all lung metastases. The positive predictive value of the CXR was 93.3%, the negative predictive value 96.7%, the sensitivity 60.8% and the specificity 99.6%. The accuracy was 96.9%. CT overestimated metastases in 4% with a sensitivity of 100%, specificity of 99.6% and accuracy of 99.6%. Median survival of patients with lung metastases at diagnosis was 11 months and there was no significant difference in survival between those who had metastases detected on CXR or purely on CT.

DISCUSSION

We recommend that all patients with a suspected STS should have a CXR at presentation, prior to histological diagnosis. CT of the chest should then be performed in those patients with an abnormality on the presentation CXR and routinely in those patients who have large, deep seated or high/intermediate grade tumours and in certain histological subtypes where the incidence of lung metastases at diagnosis is known to be high. In our experience, this strategy will detect 93% of all chest metastases. With current treatment strategies for metastases, outcome is not likely to be affected by any delay in diagnosis.

The incidence of venous thromboembolism among patients with primary lung cancer

BACKGROUND

The incidence of venous thromboembolism (VTE) by lung cancer histology and stage is unknown.

OBJECTIVES

To determine the incidence of VTE and the risk factors associated with development of VTE in a large population-based study of patients with non-small cell and small cell lung cancer.

METHODS

The California Cancer Registry was merged with the Patient Discharge Data Set to determine the incidence of VTE among lung cancer cases diagnosed between 1993 and 1999.

RESULTS

Among 91 933 patients with newly diagnosed lung cancer, the 1-year and 2-year cumulative VTE incidences were 3.0% and 3.4%, respectively, with a person-time rate of 7.2 events/100 patient-years during the first 6 months. The 1-year incidence of VTE was significantly increased in comparison to the general population [standardized incidence ratio = 21.2, 95% confidence interval (CI) = 20.4-22.0]. In a multivariate model, significant predictors of developing VTE within 1 year of non-small cell lung cancer (NSCLC) diagnosis were: younger age, the number of chronic medical comorbidities [hazard ratio (HR) = 2.8 if 3 vs. 0, 95% CI = 2.5-3.1], advancing cancer stage (HR = 4.0 for metastatic vs. local disease, 95% CI = 3.4-4.6) and adenocarcinoma histology (HR = 1.9 vs. squamous cell, 95% CI = 1.7-2.1). In multivariate models, VTE was a significant predictor of death within 2 years for both NSCLC and small cell lung cancer (SCLC), HR = 2.3, 95% CI = 2.2-2.4, and HR = 1.5, 95% CI = 1.3-1.7, respectively.

CONCLUSIONS

Approximately 3% of lung cancer patients developed VTE within 2 years. The diagnosis of VTE was associated with a higher risk of death within 2 years for NSCLC and SCLC.

Post-operative imaging of soft tissue sarcomas

Soft tissue sarcomas are uncommon malignancies that have a high risk of local recurrence despite adequate initial surgery. The aim of follow-up imaging with any malignancy is to detect recurrence promptly so that treatment can be instigated at the earliest possible opportunity. In this review article, we discuss the imaging modalities that can be employed to detect local recurrence following surgery for an extremity soft tissue sarcoma. The role of radiographs, computed tomography, magnetic resonance imaging and positron emission tomography is reviewed followed by a discussion on the imaging modalities useful in the detection of metastatic disease. Finally, we present a robust pathway that is suggested for the follow-up of patients with an extremity soft tissue sarcoma.

Neurotrophic factors and neuronal death

The well-documented physiological role of nerve growth factor (NGF) in peripheral sympathetic and neural-crest-derived sensory neurons in vivo has its exact counterpart in vitro. This provided the conceptual basis for developing in vitro analytical procedures for the purification of new neurotrophic molecules. The experimental approaches used are discussed in the context of the purification of new neurotrophic factors, brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF). The importance of the modulatory role played by extracellular matrix molecules, in particular laminin, on both NGF-mediated and BDNF-mediated survival effects is also delineated. BDNF is a very basic (pI approximately 10) molecule of about 12 kDa, having physico-chemical characteristics close to those of the monomer of NGF. However, the spectrum of its biological actions is distinctly different from that of NGF. In particular, BDNF supports the survival of retinal ganglion cells and placode-derived peripheral sensory neurons which are not supported by NGF. The trophic supply of primary sensory neurons projecting to both the central nervous system and the periphery is discussed. It is hypothesized that sensory neurons receive limited quantities of neurotrophic molecules from both peripheral and central axons, a mechanism ensuring the survival of neurons adequately connected with both peripheral and central targets.

Sarcomatous transformation in diaphyseal aclasis

Multiple hereditary exostosis (or diaphyseal aclasis) is a condition characterized by the development of multiple osteochondromas. The tendency for malignant transformation into chondrosarcoma is well known. Malignancy typically arises from the cartilaginous cap of the osteochondroma. Radiographs supplemented by computed tomography have an important role in the diagnosis of this condition. Magnetic resonance imaging shows the features of sarcomatous change and aids in differentiating malignancy from pseudotumours.

Intra-osseous pseudoaneurysm following curettage of an aneurysmal bone cyst

BACKGROUND

Pseudoaneurysms secondary to bone tumours are rare and most of the reported cases are related to osteochondromas, either due to direct pressure or following surgery. Aneurysmal bone cysts are relatively common bony lesions usually treated by curettage.

DISCUSSION

We describe an unusual case of pseudoaneurysm of the anterior tibial artery complicating curettage of an aneurysmal bone cyst which presented as a rapidly enlarging mass clinically thought to be rapid recurrence of the tumour. This was successfully treated by embolisation.

The role of MR imaging in the diagnostic characterisation of appendicular bone tumours and tumour-like conditions

MRI has an established role in the local staging of primary bone tumours. However, as the majority of tumours have non-specific appearances on MRI, the diagnosis is usually established on the basis of clinical history, plain film findings and biopsy. This article reviews the value of MRI in the further characterisation of appendicular bone tumours and tumour-like lesions, with particular reference to peri-lesional oedema, fluid-fluid levels, flow voids, fat signal, cartilage signal and dedifferentiation. These features are a useful adjunct for distinguishing between benign and malignant disease, pointing towards a more specific diagnosis, and guiding biopsy.