An Epidemiological Study of Foot and Ankle Motocross Motorcycling Injuries in the United Kingdom.

BACKGROUND: Motocross is a recreational and competitive sport involving motorcycle racing on off-road circuits. Participants have enjoyed their sport worldwide for over 100 years. In the United Kingdom, there are over 200 clubs, with over 900 events annually. Unfortunately, little evidence exists on motocross injuries and their prevention. The aim of this study is to report and to quantify the different foot and ankle injuries observed in motocross. METHODS: Data was collected prospectively between August 2010 to August 2015 at our regional trauma unit, regardless of whether the sport was performed competitively or recreationally. RESULTS: Foot and ankle related injuries were identified in 210 patients (age range 4-78 years), with the majority being male participants (189, 90%). The majority of injuries occurred within the 21- to 30-year-old-age group. Most injuries were sustained around the start of the motocross season, in early spring and the summer months. A total of 76 patients (36%) required operative intervention. The most common injury was ankle fracture (49, 23%), followed by ankle sprain (44, 21%). CONCLUSION: This is the first epidemiological study in the United Kingdom documenting foot and ankle injuries in motocross. The frequency and severity of motocross-related injuries is presented. This may serve to provide recommendations and guidelines in the governing bodies of this sport. The surge in motocross popularity is correlates with an increase in injuries and inevitably the resources required to treat them. LEVEL OF EVIDENCE: Prospective descriptive epidemiological study. Level 1.

Reliability of stemless shoulder arthroplasty in rheumatoid arthritis: observation of early lysis around the humeral component.

PURPOSE: To evaluate whether stemless shoulder implants in rheumatoid arthritis (RA) patients provide comparable functional outcomes to patients with osteoarthritis or post-traumatic arthritis. In addition, the study assessed for differences in incidence of radiolucent lines or proximal humeral bone loss during radiographic follow-up. METHODS: Consecutive stemless shoulder arthroplasties performed in RA patients and a matched control group were retrospectively identified between February 2012 and 2018. Thirty-five patients were included in each group: 24 total shoulder arthroplasty (TSA) and 11 hemiarthroplasty (HA). Patients were evaluated annually using the Oxford Shoulder Score (OSS) and radiographically. RESULTS: The mean OSS significantly improved in all groups until 24 months. The mean improvement for RA TSA and HA patients at 24 months was 19.86 (95% CI 10.66-29.05, p = 0.0004) and 19.71 (95% CI 7.33-32.31, p = 0.0084), respectively. The mean improvement in the control TSA and HA patients at 24 months was 20.86 (95% CI 17-24.71, p = 0.0001) and 17.86 (95% CI 1.36-34.35, p = 0.0381), respectively. During the study period, two patients in the RA TSA group (8%), one patient in the control TSA group (4%) and one patient in the control HA group (9%) required revision. The proportion of progressive proximal humeral bone loss after TSA was 33% in the RA group and 13% in the control group. CONCLUSION: Stemless shoulder implants can provide significant improvement in functional scores in RA patients in the short term. However, early bone loss around the humeral implant is a concern and the authors recommend long-term clinical and radiological follow-up.

In rats gestational iron deficiency does not change body fat or hepatic mitochondria in the aged offspring.

Mitochondrial dysfunction and resulting changes in adiposity have been observed in the offspring of animals fed a high fat (HF) diet. As iron is an important component of the mitochondria, we have studied the offspring of female rats fed complete (Con) or iron-deficient (FeD) rations for the duration of gestation to test for similar effects. The FeD offspring were ~12% smaller at weaning and remained so because of a persistent reduction in lean tissue mass. The offspring were fed a complete (stock) diet until 52 weeks of age after which some animals from each litter were fed a HF diet for a further 12 weeks. The HF diet increased body fat when compared with animals fed the stock diet, however, prenatal iron deficiency did not change the ratio of fat:lean in either the stock or HF diet groups. The HF diet caused triglyceride to accumulate in the liver, however, there was no effect of prenatal iron deficiency. The activity of the mitochondrial electron transport complexes was similar in all groups including those challenged with a HF diet. HF feeding increased the number of copies of mitochondrial DNA and the prevalence of the D-loop mutation, however, neither parameter was affected by prenatal iron deficiency. This study shows that the effects of prenatal iron deficiency differ from other models in that there is no persistent effect on hepatic mitochondria in aged animals exposed to an increased metabolic load.

The expression of Escherichia coli diaminopimelate decarboxylase in mouse 3T3 cells.

We have subcloned the coding sequence for the Escherichia coli lysA gene coding for diaminopimelic acid decarboxylase (DAP decarboxylase) into a eukaryotic expression vector based on the SV40 early promoter. The activities of a series of constructs with different lengths of non-coding DNA at the 5' and 3' ends of the coding region have been compared by measuring the synthesis of lysine from diaminopimelic acid (DAP) in mouse 3T3 cells. A short non-coding sequence at the 3' end reduced the expression of enzyme activity. Stable lines of 3T3 cells have been produced by co-transfection of the chimeric gene with a plasmid coding for G-418 resistance. Cells were grown in medium containing G-418 and resistant clones were screened for an ability to synthesise lysine from DAP. [3H]Lysine produced from [3H]DAP was incorporated into cell proteins. An enzyme extract from a cell line which had incorporated two copies of the gene synthesised 0.082 nmol of lysine/min per mg protein. In the intact cell the rate of lysine synthesis is limited by the uptake of DAP which is taken up at only 5% of the rate of lysine. lysA has a potential as a reporter gene in studies of gene expression in mammalian cells.

An algorithm to standardise the investigation of the undiagnosed traumatic painful adult hip: results at one year.

INTRODUCTION: A significant number of adults present to accident and emergency departments with a painful hip following a fall. When plain radiography is non-diagnostic, it has been traditionally difficult to decide on further investigations as rapid access MRI is still unavailable in many NHS hospitals and, therefore, alternative methods of reliable investigation are required. PATIENTS & METHODS: An algorithm was designed for the management of these patients without the availability of MRI investigation. Over a 60-week period, 278 patients were admitted of whom 31 were adult patients with trauma-related hip pain with no fracture on plain radiography. RESULTS: We revealed 42% had fractures of the hip or pelvic girdle. None of the hip fractures deteriorated to a worse prognostic grade during the investigation process and no hip fractures were missed. CONCLUSIONS: This approach towards a challenging diagnostic problem has been successful in identifying all hip fractures, and no fracture has deteriorated to a worse prognostic group.

Evidence that the hypertrophic action of clenbuterol on denervated rat muscle is not propranolol-sensitive.

1. The effect of propranolol on the clenbuterol-induced protein anabolism in innervated and denervated soleus and plantaris muscles of the rat was studied. 2. The response to the beta-agonist, clenbuterol, in both innervated and denervated muscles, was not significantly inhibited by the beta-antagonist, propranolol. 3. The results provide further evidence to suggest that the action of clenbuterol on skeletal muscle protein accretion may not be directly mediated by beta-adrenoceptors.

Secondary prevention of osteoporosis: when should a non-vertebral fracture be a trigger for action?

The burden of non-vertebral fractures is enormous. Hip fractures account for nearly 10% of all fractures (and a much greater proportion in the elderly), while wrist fractures may account for up to 23% of all limb fractures. The best available predictors of non-vertebral fracture risk are low BMD and a tendency to fall. Hip, forearm, proximal humerus and rib fractures have all been associated with low BMD, though ankle fracture is not strongly related to osteoporosis. Although clinical risk factors identify only about one-third of postmenopausal women at increased risk of osteoporotic fracture, the occurrence of one fracture commonly predicts a second fracture. Guidelines are presented for identifying and treating patients at risk of non-vertebral osteoporotic fractures, especially those with a previous fracture, based on the algorithm recently published by the Royal College of Physicians and the Bone and Tooth Society. Prevention of falls and use of external hip protectors may reduce the occurrence of hip fracture. Treatment options for patients presenting with hip fracture include HRT, bisphosphonates, and calcium plus vitamin D, and for Colles' fracture include general measures, HRT, bisphosphonates, or calcitonin plus calcium.

Propranolol apparently separates the physical and compositional characteristics of muscle growth induced by clenbuterol.

The effect of propranolol on clenbuterol-induced changes in muscle fibre size and protein content were studied. Propranolol did not inhibit the ability of clenbuterol to stimulate protein accretion but reduced the increase in muscle fibre size. The compositional and physical characteristics of clenbuterol-induced muscle growth thus appeared to be separated by propranolol.

Protein synthesis in skeletal muscle measured at different times during a 24 hour period.

Six groups of 5 male rats (starting body weight 109 g) were allowed free access to a conventional rat diet. At 4 hourly intervals, starting at 10.00 h muscle protein synthesis was measured. By relating the weights of the gastrocnemius and soleus muscles to the initial body weights of the animals (i.e., at 09.30, day 1), a linear increase in muscle weight throughout the day was demonstrated. The fractional rate of muscle protein synthesis varied from 16.8% per day to 20.3% per day in gastrocnemius muscle and from 17.9% per day and 22.1% per day in the soleus. It was calculated that the maximum error incurred in estimating daily muscle protein synthesis by extrapolation of the value at any one time was 6% in gastrocnemius and 9% in soleus. It is concluded that calculations of the average rate of muscle protein degradation based on the difference between the rates of synthesis and deposition are generally valid in rats allowed free access to an adequate diet.

Clenbuterol, a beta agonist, induces growth in innervated and denervated rat soleus muscle via apparently different mechanisms.

Dietary administration of the anabolic agent, clenbuterol, has already been shown to inhibit or reverse denervation-induced atrophy in rat soleus muscles. We now show that the ameliorative effects of clenbuterol in denervated rat muscles are due principally to a large increase in protein synthesis. This results from both an increase in protein synthetic capacity and a normalised translational efficiency. The responses of innervated and denervated muscles are therefore fundamentally different, the changes in denervated muscles being reminiscent of the classical pleiotypic response of cells to growth factors.

The effect of the anabolic agent, clenbuterol, on overloaded rat skeletal muscle.

The dietary administration of clenbuterol to young male rats has been shown to produce a muscle specific hypertrophic growth response. This paper demonstrates that the combined effect of drug treatment and hypertrophic stimulus induced by tenotomy produced an additive effect on muscle growth. This effect was demonstrated in terms of both muscle composition (protein and RNA) and fibre size.

Inhibition and reversal of denervation-induced atrophy by the beta-agonist growth promoter, clenbuterol.

Dietary administration of the growth promoter, clenbuterol, ameliorated denervation-induced atrophy in rat soleus muscles. In acutely denervated muscles the drug inhibited the appearance of atrophy, and in chronically denervated muscles the atrophy was almost fully reversed. Responses in slow twitch oxidative fibres were particularly marked.

Acute transient bilateral trigger fingers.

A 30-year-old man presented with bilateral, simultaneous, transient triggering of the middle digits which developed acutely after prolonged and sustained use of a garden rotavator. He was asymptomatic in the period before presentation and has remained so 7 years since.

Perthes disease affecting three female first-degree relatives.

Perthes disease has an incidence of 1 in 4,750 live births (1 in 3,000 boys, but only 1 in 11,800 girls). Although there is evidence for a genetic predisposition to Perthes disease, more than two family members are rarely affected. We report the first recorded case of Perthes disease affecting three female first-degree relatives.

The effect of clenbuterol administration in utero and throughout lactation on pre- and post-natal muscle development in the rat.

The beta-adrenergic agonist, clenbuterol was fed to pregnant rats during gestation and throughout lactation. Changes in muscle morphology and composition were studied in foetal and weanling rats. Drug treatment did not affect mean foetal number, but mean foetal body weight was significantly reduced. Heart weights were increased and both muscle weight and secondary to primary fibre ratios were decreased in foetuses exposed to clenbuterol in utero. In animals exposed to clenbuterol throughout gestation and lactation, muscle weights, and protein, RNA and DNA content and total fibre numbers were reduced. In addition a drug induced anabolism was observed in the muscles of the dams. The data are discussed in terms of a direct drug effect on immature and differentiated muscle together with a possible indirect action through the repartitioning action of clenbuterol.

Unusual cases of elbow locking due to synovial cysts: a report of two cases.

Sudden and intermittent locking of the elbow joint is a com- mon complaint among patients who commonly demonstrate degenerative changes in the elbow. Common causes of elbow locking include acute trauma, osteochondritis dessicans, synovial chondromatosis, and osteoarthritis. Two cases involving patients with symptoms of elbow locking secondary to reasons other than loose bodies within the joint are presented: a synovial cyst within the posterior aspect of the elbow, specifically within the olecranon fossa causing their painful symptoms of locking. These cases present unique features in the diagnostic approaches of elbow locking due to the unexpected association with synovial cysts. We believe that these findings can shed new light on the pathogenesis of this disease.

The biosynthesis of threonine by mammalian cells: expression of a complete bacterial biosynthetic pathway in an animal cell.

The coding regions for the Escherichia coli gene for aspartokinase I/homoserine dehydrogenase I (thrA) and the Corynebacterium glutamicum gene for aspartic semialdehyde dehydrogenase (asd) have been subcloned into a Simian Virus 40 (SV40)-based mammalian expression vector. Both enzyme activities are expressed in mouse 3T3 cells after transfer of the corresponding chimaeric gene. The kinetic parameters are similar to those of the native bacterial enzymes, and aspartokinase I/homoserine dehydrogenase I retains its allosteric regulation by threonine. An extract of the cells expressing aspartokinase I/homoserine dehydrogenase I, mixed with one from cells expressing aspartic semialdehyde dehydrogenase, produced homoserine when the mixture was incubated with aspartic acid, ATP and NADPH. The thrA and asd expression cassettes were combined into a single plasmid which, when transfected into 3T3 cells, enabled them to produce homoserine from aspartic acid. Homoserine-producing 3T3 cells were transfected with the plasmid pSVthrB/C (homoserine kinase and threonine synthase) and selected for growth on homoserine. Cell lines isolated from these cells expressed the complete bacterial threonine pathway, were independent of threonine for growth and could be maintained in medium which contained no free threonine. The threonine in the proteins of these cells became enriched in 15N when the culture medium contained [15N]aspartic acid. The production of homoserine and the growth of cells was at a maximum when there was more than 2.5 mM aspartate in the medium. Below this concentration the high Km of aspartokinase limited the flux through the pathway. In the presence of additional aspartic acid the new pathway could sustain a cell cycle time close to that of the same cells cultured in threonine-containing medium.

The expression of Escherichia coli threonine synthase and the production of threonine from homoserine in mouse 3T3 cells.

We have subcloned the coding sequence for the Escherichia coli threonine synthase gene into a eukaryotic expression vector based on the simian-virus-40 early promoter. When mouse 3T3 cells which already expressed homoserine kinase were transfected with the new plasmid, the cells were able to incorporate radioactivity from [14C]homoserine into their cell proteins. Stable cell lines were established by co-transfecting 3T3 cells with the plasmid coding for threonine synthase and another coding for homoserine kinase and G-418 (Geneticin) resistance. Cells were selected for G-418 resistance and then screened for an ability to synthesize threonine from homoserine and incorporate it into the cell protein. A cell line which expressed both the homoserine kinase and threonine synthase genes was capable of growth in a threonine-deficient medium containing homoserine.