Expectations of Task Demands Dissociate Working Memory and Long-Term Memory Systems

Many aspects of the complex relationship between working memory (WM) and long-term memory (LTM) remain unclear. Here, we manipulated task demands on a brief delayed-recognition paradigm to reveal behavioral and neural dissociations between these systems. Variations from a Baseline task included 3 challenges: increased delay duration, distraction during maintenance, and more closely matched memory probes, which were presented in behavioral experiments and during functional magnetic resonance imaging. Each of the challenges resulted in a significant decline in WM accuracy, and interestingly, a concurrent improvement in incidental LTM. Neural data revealed that, in task blocks, when participants anticipated, and then experienced, increased demands, they engaged medial temporal lobe (MTL) regions more during both the encoding and delay periods. Overall, these results indicate that distinct memory systems are recruited based on anticipated demands of a memory task, and MTL involvement underlies the observed dissociation between WM and LTM performance.

Anatomic anterior cruciate ligament (ACL) reconstruction: a global perspective. Part 1

PURPOSE

In August 2011, orthopaedic surgeons from more than 20 countries attended a summit on anatomic anterior cruciate ligament (ACL) reconstruction. The summit offered a unique opportunity to discuss current concepts, approaches, and techniques in the field of ACL reconstruction among leading surgeons in the field.

METHODS

Five panels (with 36 panellists) were conducted on key issues in ACL surgery: anatomic ACL reconstruction, rehabilitation and return to activity following anatomic ACL reconstruction, failure after ACL reconstruction, revision anatomic ACL reconstruction, and partial ACL injuries and ACL augmentation. Panellists' responses were secondarily collected using an online survey.

RESULTS

Thirty-six panellists (35 surgeons and 1 physical therapist) sat on at least one panel. Of the 35 surgeons surveyed, 22 reported performing "anatomic" ACL reconstructions. The preferred graft choice was hamstring tendon autograft (53.1 %) followed by bone-patellar tendon-bone autograft (22.8 %), allograft (13.5 %), and quadriceps tendon autograft (10.6 %). Patients generally returned to play after an average of 6 months, with return to full competition after an average of 8 months. ACL reconstruction "failure" was defined by 12 surgeons as instability and pathological laxity on examination, a need for revision, and/or evidence of tear on magnetic resonance imaging. The average percentage of patients meeting the criteria for "failure" was 8.2 %.

CONCLUSIONS

These data summarize the results of five panels on anatomic ACL reconstruction. The most popular graft choice among surgeons for primary ACL reconstructions is hamstring tendon autograft, with allograft being used most frequently employed in revision cases. Nearly half of the surgeons surveyed performed both single- and double-bundle ACL reconstructions depending on certain criteria. Regardless of the technique regularly employed, there was unanimous support among surgeons for the use of "anatomic" reconstructions using bony and soft tissue remnant landmarks.

Distal radio-ulnar joint instability in children and adolescents after wrist trauma

This study retrospectively evaluated the medical records and radiographs of patients younger than aged 25 that were referred for a second opinion due to ulnar-sided wrist pain and persistent distal radio-ulnar (DRU) joint instability. We identified 85 patients with a major wrist trauma before the age of 18. Median age at trauma was 14 years. Median time between trauma and diagnosis of DRUJ instability was 3 years. Sixty-seven patients (79%) had sustained a fracture at the initial trauma. The two most common skeletal injuries related to the DRUJ instability were Salter-Harris type II fractures (24%) and distal radius fractures (19%). In 19 patients (22%), the secondary DRUJ instability was caused by malunion or growth arrest. Eighteen patients (21%) had no fracture; in spite of this, they presented with subsequent symptomatic DRUJ instability. Fourteen of these 18 patients had a triangular fibrocartilage complex (TFCC) tear, confirmed by arthroscopy, open surgery, or magnetic resonance imaging. In conclusion, late DRUJ instability due to wrist fractures or isolated TFCC tears was found to be common in children and adolescents.

LEVEL OF EVIDENCE

IV.

Is buprenorphine transdermal patch equally safe and effective in younger and elderly patients with osteoarthritis-related pain? Results of an age-group controlled study

OBJECTIVE

A recent pharmacokinetic study with buprenorphine transdermal patches showed similar systemic exposures of buprenorphine in subjects aged ≥75 and 50-60 years. The current prospective, open-label study aimed to verify this in a clinical setting by evaluating efficacy and safety of buprenorphine patches in patients with chronic osteoarthritis (OA) pain.

METHODS

Patients with chronic, moderate to severe osteoarthritic pain (hip and/or knee) were enrolled: 50-60 years (younger group, N = 65) and ≥75 years (elderly group, N = 57). After 2 weeks on paracetamol only, patients received buprenorphine patches (5-40 µg/h) for 12 weeks. Paracetamol rescue was provided. Primary endpoint was the Box-Scale-11 (BS-11) score for pain on average over the last week. WOMAC OA Index, EQ-5D, Patients' and Investigators' Global Assessment of Pain Relief, rescue medication use, sleep disturbance and quality of sleep were secondary efficacy endpoints.

RESULTS

Both groups showed a statistically significant (p < 0.0001) and clinically relevant change from baseline to last visit in BS-11 score, with no significant difference between groups. The least squares (LS) mean change from baseline was 2.20 in elderly and 1.87 in younger patients, with an age group difference of 0.33 (95% CI: -0.42, 1.07). Non-inferiority of the elderly versus the younger group was shown. Both age groups showed a significant improvement in WOMAC total score, patients' overall health state (EQ-5D visual analogue scale) and sleep quality, and a significant reduction in rescue use and nights woken due to pain, with no significant differences between groups. Elderly patients tolerated buprenorphine patches at least as well as younger patients.

CONCLUSIONS

Efficacy and tolerability of buprenorphine patches was demonstrated in chronic pain patients, regardless of age, supporting the conclusion that no age-related dose adjustment of transdermal buprenorphine is needed. A study limitation is lack of active control but no other opioid was appropriate in elderly patients or this indication.

Reliability of Achilles tendon resting angle and calf circumference measurement techniques

BACKGROUND

The resting angle of the ankle joint may be altered following apparently successful management of Achilles tendon rupture. The reliability of the Achilles Tendon Resting Angle and Calf Circumference measurements was determined.

METHODS

Three test-retest measurements for reliability assessment were performed on 16 healthy subjects: 10 males and 6 females.

RESULTS

The mean left Achilles Tendon Resting Angle was mean 50.1° (range [26-61]), ICC 0.92 (CI [0.83-0.97]), SEM 2.4°. The mean right Achilles tendon resting angle was mean 49.9° (range [26-60]), ICC 0.91 (CI [0.80-0.96]), SEM 2.6°. The mean left calf circumference was mean 38.5cm (range [33.3-44.2]), ICC 0.97 (CI [0.94-0.98]), SEM 0.6cm, and the mean right calf circumference was mean 38.4cm (range [33.3-43.6]), ICC 0.97 (CI [0.94-0.99]), SEM 0.5cm.

CONCLUSIONS

The Achilles Tendon Resting Angle and Calf Circumference at 15cm from the antero-medial joint line had excellent test-retest reliability. These are simple, quick and inexpensive measurements, which have the potential to correlate with tendon elongation and functional outcome. The Achilles tendon resting angle may be used as a guide to tendon length during intra-operative repair and rehabilitation.

Raloxifene and alendronate containing thin mesoporous titanium oxide films improve implant fixation to bone

This study tested the hypothesis that osteoporosis drug-loaded mesoporous TiO2 implant coatings can be used to improve bone-implant integration. Two osteoporosis drugs, Alendronate (ALN) and Raloxifene (RLX), were immobilized in nanoporous oxide films prepared on Ti screws and evaluated in vivo in rat tibia. The drug release kinetics were monitored in vitro by quartz crystal microbalance with dissipation and showed sustained release of both drugs. The osteogenic response after 28days of implantation was evaluated by quantitative polymerase chain reaction (qPCR), removal torque, histomorphometry and ultrastructural interface analysis. The drug-loaded implants showed significantly improved bone fixation. In the case of RLX, stronger bone-remodelling activity was observed compared with controls and ALN-loaded implants. The ultrastructural interface analysis revealed enhanced apatite formation inside the RLX coating and increased bone density outside the ALN coating. Thus, this novel combination of a thin mesoporous TiO2 carrier matrix and appropriate drugs can be used to accelerate implant fixation in trabecular bone.

Whole body vibration therapy in patients with Duchenne muscular dystrophy--a prospective observational study

OBJECTIVES

To study the tolerability of whole body vibration (WBV) exercise in patients with Duchenne muscular dystrophy (DMD) and its effects on muscle and bone.

METHODS

WBV was performed two to three times a week for three months. Motor function, muscle strength, bone mass and biochemical markers of bone and mineral metabolism were analyzed before and after the WBV period at 0, 3, 6 and 12 months.

RESULTS

Six ambulatory patients with DMD aged 5.7-12.5 years completed the study. No changes in creatine kinase activity were found, indicating that the WBV exercise did not further damage the skeletal muscle. No significant changes in bone mass, muscle strength or bone markers were found. However, there was a non-significant trend for the bone formation marker, bone-specific alkaline phosphate, to increase from a mean of 59 U/L to 73 U/L after three months of WBV. The bone formation marker levels returned to baseline three months after discontinuing WBV and were still at that level after nine months.

CONCLUSIONS

WBV therapy appears to be safe and well tolerated among ambulatory DMD patients. The potential benefits of WBV on bone and muscle in DMD remain to be elucidated.

Ability to perform a single heel-rise is significantly related to patient-reported outcome after Achilles tendon rupture

This study evaluated the short-term recovery of function after an acute Achilles tendon rupture, measured by a single-legged heel-rise test, with main emphasis on the relation to the patient-reported outcomes and fear of physical activity and movement (kinesiophobia). Eighty-one patients treated surgically or non-surgically with early active rehabilitation after Achilles tendon rupture were included in the study. Patient's ability to perform a single-legged heel-rise, physical activity level, patient-reported symptoms, general health, and kinesiophobia was evaluated 12 weeks after the injury. The heel-rise test showed that 40 out of 81 (49%) patients were unable to perform a single heel-rise 12 weeks after the injury. We found that patients who were able to perform a heel-rise were significantly younger, more often of male gender, reported a lesser degree of symptoms, and also had a higher degree of physical activity at 12 weeks. There was also a significant negative correlation between kinesiophobia and all the patient-reported outcomes and the physical activity level. The heel-rise ability appears to be an important early achievement and reflects the general level of healing, which influences patient-reported outcome and physical activity. Future treatment protocols focusing on regaining strength early after the injury therefore seem to be of great importance. Kinesiophobia needs to be addressed early during the rehabilitation process.

Terminology for Achilles tendon related disorders

The terminology of Achilles tendon pathology has become inconsistent and confusing throughout the years. For proper research, assessment and treatment, a uniform and clear terminology is necessary. A new terminology is proposed; the definitions hereof encompass the anatomic location, symptoms, clinical findings and histopathology. It comprises the following definitions: Mid-portion Achilles tendinopathy: a clinical syndrome characterized by a combination of pain, swelling and impaired performance. It includes, but is not limited to, the histopathological diagnosis of tendinosis. Achilles paratendinopathy: an acute or chronic inflammation and/or degeneration of the thin membrane around the Achilles tendon. There are clear distinctions between acute paratendinopathy and chronic paratendinopathy, both in symptoms as in histopathology. Insertional Achilles tendinopathy: located at the insertion of the Achilles tendon onto the calcaneus, bone spurs and calcifications in the tendon proper at the insertion site may exist. Retrocalcaneal bursitis: an inflammation of the bursa in the recess between the anterior inferior side of the Achilles tendon and the posterosuperior aspect of the calcaneus (retrocalcaneal recess). Superficial calcaneal bursitis: inflammation of the bursa located between a calcaneal prominence or the Achilles tendon and the skin. Finally, it is suggested that previous terms as Haglund's disease; Haglund's syndrome; Haglund's deformity; pump bump (calcaneus altus; high prow heels; knobbly heels; cucumber heel), are no longer used.

In vivo estimation of the contribution of elastin and collagen to the mechanical properties in the human abdominal aorta: effect of age and sex

The mechanical properties of the aorta affect cardiac function and are related to cardiovascular morbidity/mortality. This study was designed to evaluate the isotropic (mainly elastin, elastiniso) and anisotropic (mainly collagen, collagenani) material parameters within the human aorta in vivo. Thirty healthy men and women in three different age categories (23–30, 41–54, and 67–72 yr) were included. A novel mechanical model was used to identify the mechanical properties and the strain field with aid of simultaneously recorded pressure and radius in the abdominal aorta. The magnitudes of the material parameters relating to both the stiffness of elastiniso and collagenani were in agreement with earlier in vitro studies. The load-bearing fraction attributed to collagenani oscillated from 10 to 30% between diastolic and systolic pressures during the cardiac cycle. With age, stiffness of elastiniso increased in men, despite the decrease in elastin content that has been found due to elastolysis. Furthermore, an increase in stiffness of collagenani at high physiological pressure was found. This might be due to increased glycation, as well as changed isoforms of collagen in the aortic wall with age. A marked sex difference was observed, with a much less age-related effect, both on elastiniso and collagenani stiffness in women. Possible factors of importance could be the effect of sex hormones, as well as differing collagen isoforms, between the sexes.

Web service catalogue for Biomedical Grid infrastructure

A great variety of services have been developed to address problems in the field of biomedicine. The EU project Advancing Clinico-Genomics Trials on Cancer (ACGT - http://www.eu-acgt.org) provides a Grid-based platform for improved medical knowledge discovery and integration of biomedical data in clinical trials on cancer. Metadata describing biomedical services needs to be shared to enable discovery and service composition (as workflows). This paper reports a catalogue for knowledge-based discovery of service metadata and a software module to wrap existing command line programs as a secure Grid service able to handle sensitive information.

Psychometric analysis of the Three-Factor Eating Questionnaire-R21: results from a large diverse sample of obese and non-obese participants

BACKGROUND

The 21-item Three-Factor Eating Questionnaire (TFEQ-R21) is a scale that measures three domains of eating behavior: cognitive restraint (CR), uncontrolled eating (UE) and emotional eating (EE).

OBJECTIVES

To assess the factor structure and reliability of TFEQ-R21 (and if necessary, refine the structure) in diverse populations of obese and non-obese individuals.

DESIGN

Data were obtained from obese adults in a United States/Canadian clinical trial (n=1741), and overweight, obese and normal weight adults in a US web-based survey (n=1275). Confirmatory factor analyses were employed to investigate the structure of TFEQ-R21 using baseline data from the clinical trial. The model was refined to obtain adequate fit and internal consistency. The refined model was then tested using the web-based data. Relationships between TFEQ domains and body mass index (BMI) were examined in both populations.

RESULTS

Clinical data indicated that TFEQ-R21 needed refinement. Three items were removed from the CR domain, producing the revised version TFEQ-R18V2 (Comparative Fit Index (CFI)=0.91). Testing TFEQ-R18V2 in the web-based sample supported the revised structure (CFI=0.96; Cronbach's coefficient alpha of 0.78-0.94). Associations with BMI were small. In the clinical study, the CR domain showed a significant and negative association with BMI. On the basis of the web-based survey, it was shown that the relationship between BMI and CR is population-dependent (obese versus non-obese, healthy versus diabetics).

CONCLUSIONS

In two independent datasets, the TFEQ-R18V2 showed robust factor structure and good reliability. It may provide a useful tool for characterizing UE, CR and EE.

Relevance of muscle fibre type to fatigue in short intense and prolonged exercise in man

It has been suggested that the histological and histochemical features of human muscle are important in determining performance capacity. The relationship between muscle fibre types (Type I, slow twitch fibres; Type II, fast twitch fibres) and performance on standardized tests has been studied in subjects accustomed to physical exercise, and related to their patterns of lactate metabolism, expressed as the onset of blood lactate accumulation (OBLA). This variable was found to be the best predictor of endurance capacity of the variables studied. It is suggested that in healthy male subjects muscle lactate is crucial in short, intense forms of exercise (the higher the lactate formation, the better the performance) and also in prolonged, "endurance' forms of exercise (the later the onset of lactate formation, the higher the sustainable exercise intensity). In subjects with a high proportion of fast twitch fibres, more lactate will be formed at the same exercise intensity. This is advantageous for short intense exercise but impairs endurance performance. The deleterious effects induced by glycogen depletion were studied and found to be most pronounced in subjects rich in fast twitch (glycogen-dependent) fibres. Indications were also obtained that muscular performance is regulated in different ways in males and females. In women an inverse relationship was found between fast twitch fibres and muscle power, and between fatigue and lactate concentration, whereas direct relations were found in men.