Acute effects of small changes in antero-posterior shoe-cleat position on physiological and biomechanical variables in road cycling.

The aim of this study was to investigate the effect of changes in cycling shoe-cleat position on pedalling biomechanics, physiological variables, and performance in road cycling. Twelve competitive road cyclists performed three pedalling trials with the cleat positioned at the first metatarsal head, 15-mm anterior and 15-mm posterior. Each trial included three sets of 5 min performed at 35%, 50%, and 65% of maximal aerobic power (MAP) followed by a 10-s sprint. Results showed no significant changes in physiological variables, pedalling kinetics, muscular activity of six lower limb muscles, sprint performance and perceived exertion. However, significant differences were found regarding joint kinematics: hip, knee, and ankle angles during both extension and flexion were reduced in the anterior cleat position. Therefore, this study suggests that cleat position does not affect sprint performance, physiological variables, pedalling kinetics, muscle activity, and perceived exertion regardless of the cycling intensity. However, joint kinematics, and particularly knee extension angle which could be related to the risk of overuse injuries, was affected by the shoe-cleat position.

Downregulation of Grem1 expression in the distal limb mesoderm is a necessary precondition for phalanx development.

BACKGROUND: The phalanges are the final skeletal elements to form in the vertebrate limb and their identity is regulated by signaling at the phalanx forming region (PFR) located at the tip of the developing digit ray. Here, we seek to explore the relationship between PFR activity and phalanx morphogenesis, which define the most distal limb skeletal elements, and signals associated with termination of limb outgrowth. RESULTS: As Grem1 is extinguished in the distal chick limb mesoderm, the chondrogenesis marker Aggrecan is up-regulated in the metatarsals and phalanges. Fate mapping confirms that subridge mesoderm cells contribute to the metatarsal and phalanges when subridge Grem1 is down-regulated. Grem1 overexpression specifically blocks chick phalanx development by inhibiting PFR activity. PFR activity and digit development are also disrupted following overexpression of a Gli3 repressor, which results in Grem1 expression in the distal limb and downregulation of Bmpr1b. CONCLUSIONS: Based on expression and fate mapping studies, we propose that downregulation of Grem1 in the distal limb marks the transition from metatarsal to phalanx development. This suggests that downregulation of Grem1 in the distal limb mesoderm is necessary for phalanx development. Grem1 downregulation allows for full PFR activity and phalanx progenitor cell commitment to digit fate.

A Dominant Heterozygous Mutation in COG4 Causes Saul-Wilson Syndrome, a Primordial Dwarfism, and Disrupts Zebrafish Development via Wnt Signaling.

Saul-Wilson syndrome (SWS) is a rare, skeletal dysplasia with progeroid appearance and primordial dwarfism. It is caused by a heterozygous, dominant variant (p.G516R) in COG4, a subunit of the conserved oligomeric Golgi (COG) complex involved in intracellular vesicular transport. Our previous work has shown the intracellular disturbances caused by this mutation; however, the pathological mechanism of SWS needs further investigation. We sought to understand the molecular mechanism of specific aspects of the SWS phenotype by analyzing SWS-derived fibroblasts and zebrafish embryos expressing this dominant variant. SWS fibroblasts accumulate glypicans, a group of heparan sulfate proteoglycans (HSPGs) critical for growth and bone development through multiple signaling pathways. Consistently, we find that glypicans are increased in zebrafish embryos expressing the COG4 p.G516R variant. These animals show phenotypes consistent with convergent extension (CE) defects during gastrulation, shortened body length, and malformed jaw cartilage chondrocyte intercalation at larval stages. Since non-canonical Wnt signaling was shown in zebrafish to be related to the regulation of these processes by glypican 4, we assessed wnt levels and found a selective increase of wnt4 transcripts in the presence of COG4 p.G516R . Moreover, overexpression of wnt4 mRNA phenocopies these developmental defects. LGK974, an inhibitor of Wnt signaling, corrects the shortened body length at low concentrations but amplifies it at slightly higher concentrations. WNT4 and the non-canonical Wnt signaling component phospho-JNK are also elevated in cultured SWS-derived fibroblasts. Similar results from SWS cell lines and zebrafish point to altered non-canonical Wnt signaling as one possible mechanism underlying SWS pathology.

Using mobile multimedia platforms in teaching dental diagnosis.

OBJECTIVE: Mobile Multimedia Platforms (MMPs) are prolific tools that can be used by individuals and corporations to share content. However, few studies have shown the effectiveness of MMPs as educational tools. Through this study, we aimed to evaluate the effectiveness of MMPs in improving basic dental diagnostic skills. In addition, we captured student feedback on the use of MMPs in a dental curriculum. METHOD: In this voluntary interventional study on 89 senior dental students, we created pilot learning modules through an MMP called Instagram Stories to teach dental diagnosis. We evaluated the efficacy of the modules through diagnostic tests that were given to dental students who were close to graduating. RESULTS: The students showed a significant increase in diagnostic test scores from 49% to 73% (p < 0.05) after the use of an MMP. Furthermore, the students' feedback on the MMP indicated that most students found it easy and enjoyable to use. CONCLUSION: Our study data show that MMPs may be used to improve training in basic dental diagnostic skills and can serve as an adjunct teaching tool. Moreover, MMP modules can potentially enrich professional education in developing countries where access to educational resources is limited.

Evolution of the hypoxia-sensitive cells involved in amniote respiratory reflexes.

The evolutionary origins of the hypoxia-sensitive cells that trigger amniote respiratory reflexes - carotid body glomus cells, and 'pulmonary neuroendocrine cells' (PNECs) - are obscure. Homology has been proposed between glomus cells, which are neural crest-derived, and the hypoxia-sensitive 'neuroepithelial cells' (NECs) of fish gills, whose embryonic origin is unknown. NECs have also been likened to PNECs, which differentiate in situ within lung airway epithelia. Using genetic lineage-tracing and neural crest-deficient mutants in zebrafish, and physical fate-mapping in frog and lamprey, we find that NECs are not neural crest-derived, but endoderm-derived, like PNECs, whose endodermal origin we confirm. We discover neural crest-derived catecholaminergic cells associated with zebrafish pharyngeal arch blood vessels, and propose a new model for amniote hypoxia-sensitive cell evolution: endoderm-derived NECs were retained as PNECs, while the carotid body evolved via the aggregation of neural crest-derived catecholaminergic (chromaffin) cells already associated with blood vessels in anamniote pharyngeal arches.

Predictive factors of depressive symptoms of elderly patients with cancer receiving first-line chemotherapy.

BACKGROUND: Depression is the most common psychiatric disorder in geriatrics and oncology. For elderly cancer patients, it has a significant impact on quality of life, morbidity, and mortality. Nevertheless, depression is under-diagnosed and under-treated. Cancer management is key in improving the quality of care in this population. We aim to identify sociodemographic, clinical, and treatment-related factors of depression in elderly patients during chemotherapy, thus allowing early detection of patients in need of specific treatment. Further, we investigate whether chemotherapy efficacy and safety are associated with depression. PATIENTS AND METHODS: A prospective multicenter cohort composed of incident cases of cancer diagnosed in patients 70 years and older, receiving first-line chemotherapy. Depressive symptoms were measured by the Geriatric Depression Scale at baseline and after four chemotherapy cycles. Associations between depressive symptoms during chemotherapy and patients' clinical and treatment characteristics were identified by logistic regression. RESULTS: Among 344 patients measured for depression before chemotherapy, 260 had a second assessment at the fourth treatment cycle. At baseline, 45.4% were depressed, and 44.6% were depressed after the fourth cycle. Independent factors of depression were depressive symptoms at baseline (odds ratio (OR) = 6.7, p < 0.001), malnutrition (OR = 5.1, p = 0.014), and risk of malnutrition (OR = 1.6, p = 0.014). After controlling for missing data, effective chemotherapy was associated with a lower risk of depression (OR = 0.4, p = 0.018). CONCLUSION: We highlight the role of depressive symptoms and nutritional status at baseline, on the occurrence of depressive symptoms during chemotherapy. These factors should be taken into account in any pre-treatment consultation and appropriate nutritional and psychiatric preventative measures established. Copyright © 2016 John Wiley & Sons, Ltd.

Sexual quality of life is impaired in patients with chronic hepatitis C.

Chronic hepatitis C (CHC) patients often have altered quality of life. Few data are available about sexual impairment (SI) in CHC. From 2011 to 2013, we included consecutive CHC outpatients. Exclusion criteria were: antiviral therapy, co-infection, age <18 or >75, transplantation, alcohol consumption, Eastern Cooperative Oncology Group >1. Non-CHC subjects were healthy blood donors. Sexual questionnaires for men and women were adapted from the International Index of Erectile Function and Female Sexual Function Index, respectively, and concerned the past 30 days. Two hundred eighty-one patients were compared with 1086 blood donors. SI was more frequent in CHC patients. Men with CHC had worse desire, confidence, erections, climax and satisfaction (P<0.001). Women with CHC had worse desire, arousal, climax, satisfaction, lubrication and comfort (P<0.001). In multivariate analysis, factors associated with SI in men were CHC (odds ratio (OR)=4.45, 95% confidence interval (CI) 2.46-8.06), age (OR=1.06, 95% CI 1.03-1.09), no intercourse (OR=8.74, 95% CI 4.65-16.04) and unemployment (OR=2.14, 95% CI 1.16-3.95). Factors associated with a worse global sexual life in women were CHC (OR=7.96, 95% CI 4.07-15.58) and no intercourse (OR=21.39, 95% CI 11.03-41.48). The study results were corroborated by propensity score-matching analysis. Sexual life is impaired in men and women with CHC. In clinical practice, sexual quality of life should be evaluated and treated.

Complications arising after thoracic aortic surgery: a case report on an unusual spinal cord infarction. Physiopathological and clinical considerations.

Even though new prevention techniques have been developed and are being used during thoraco-abdominal aortic repairs, spinal cord infarction remains a severe and relatively frequent complication of aortic surgery. Infarctions in the territory of the anterior spinal artery are considered the most common. Different clinical pictures related to spinal cord transverse extension wounds are drawn up. In this paper, we present a case report of a subject having presented an isolated motor deficit of the lower limbs and a favorable prognosis, suggesting selective involvement of the anterior horns of the spinal cord subsequent to surgical repair of an aortic dissection. We wish to review the relevant anatomical, clinical and diagnostic characteristics along with current techniques of spinal cord ischemia prevention during and after surgery.

Physiology of ski mountaineering racing.

The aim of this study was to quantify and describe the exercise intensity of ski mountaineering racing, and to identify the best physiological predictors of ski mountaineering racing. Before participating in the race in which heart rate (HR) and speed were continuously recorded, 10 trained ski-mountaineers performed a field maximal test to determine the first ventilatory threshold (VT1) and the respiratory compensation threshold (RCT) in order to establish 3 exercise intensity zones (Z1: below VT1, Z2: between VT1 and RCT, and Z3: above RCT). Energy cost (EC) of each subject was estimated on the HR/ V˙O2 relationship obtained during the field maximal test. VT1 and RCT threshold were equal to 84.2±3.0 and 94.5±1.7% of HR (max). Race time was significantly correlated with V˙O2max (r = -0.87), VT1 (r = -0.82) and RCT (r = -0.85) expressed for body mass unit. The mean race time and the mean HR were 101±11 min and 93.4±1.8% of HR (max). The % race time spent in Z1, Z2 and Z3, were 7.0±4.8, 51.3±4.7 and 42.0±6.5%, respectively. The mean value of EC during the two uphill of the race was 14.3±2.6 J x kg(-1) x m(-1). HR and speed decreased significantly during the second uphill whereas EC increased significantly by ∼15%. Data obtained in the present study represent the first qualitative description of physiology demand of ski mountaineering racing. The long period of time spent just below and above RCT suggest that ski-mountaineering can be viewed as one of the most strenuous endurance sports like cross-country skiing, running and off-road biking. In addition to high aerobic capacities, body mass seems to appear as a key factor given that performance in ski mountaineering is strongly correlated to relative common physiological variables. The changes of HR, speed and EC during the second uphill, which indicate the prevalence of fatigue, confirm the exhaustive character of ski mountaineering.

Physiological and neuromuscular responses of competitive cyclists during a simulated self-paced interval training session.

Responses of twelve competitive cyclists performing an interval training session, consisting of three successive 10-min self-paced exercise bouts separated by two 15-min active recovery periods, were studied. Power output (PO), heart rate, pedaling cadence, ventilatory variables, overall ratings of perceived exertion (RPE) and electromyographic (EMG) activity of the vastus lateralis, vastus medialis, biceps femoris and medial hamstrings were recorded during each exercise bout. Mean PO (p<0.05) decreased significantly across the self-paced bouts, while RPE (p<0.01) increased significantly. PO and EMG activity did not show significant changes between the 3rd and 9th minute of each self-paced bout. Every self-paced bout showed an oxygen uptake (VO(2)) slow component between the 3rd and 9th minute and there was no effect of bout order on the magnitude of the VO(2) slow component. This study reveals that during an interval training session, moderately trained competitive cyclists are able to repeat three 10-min self-paced exercise bouts with only a slight decrease in PO (approximately 3%) and by maintaining unchanged physiological and neuromuscular responses. Moreover, the VO(2) slow component during each exercise bout was not related to changes in muscle activity, as every exercise bout was performed at a muscular work steady state with a constant PO.

Muscular activity during uphill cycling: effect of slope, posture, hand grip position and constrained bicycle lateral sways.

Despite the wide use of surface electromyography (EMG) to study pedalling movement, there is a paucity of data concerning the muscular activity during uphill cycling, notably in standing posture. The aim of this study was to investigate the muscular activity of eight lower limb muscles and four upper limb muscles across various laboratory pedalling exercises which simulated uphill cycling conditions. Ten trained cyclists rode at 80% of their maximal aerobic power on an inclined motorised treadmill (4%, 7% and 10%) with using two pedalling postures (seated and standing). Two additional rides were made in standing at 4% slope to test the effect of the change of the hand grip position (from brake levers to the drops of the handlebar), and the influence of the lateral sways of the bicycle. For this last goal, the bicycle was fixed on a stationary ergometer to prevent the lean of the bicycle side-to-side. EMG was recorded from M. gluteus maximus (GM), M. vastus medialis (VM), M. rectus femoris (RF), M. biceps femoris (BF), M. semimembranosus (SM), M. gastrocnemius medialis (GAS), M. soleus (SOL), M. tibialis anterior (TA), M. biceps brachii (BB), M. triceps brachii (TB), M. rectus abdominis (RA) and M. erector spinae (ES). Unlike the slope, the change of pedalling posture in uphill cycling had a significant effect on the EMG activity, except for the three muscles crossing the ankle's joint (GAS, SOL and TA). Intensity and duration of GM, VM, RF, BF, BB, TA, RA and ES activity were greater in standing while SM activity showed a slight decrease. In standing, global activity of upper limb was higher when the hand grip position was changed from brake level to the drops, but lower when the lateral sways of the bicycle were constrained. These results seem to be related to (1) the increase of the peak pedal force, (2) the change of the hip and knee joint moments, (3) the need to stabilize pelvic in reference with removing the saddle support, and (4) the shift of the mass centre forward.

[Osteoid osteoma. CT guided drilling and radiofrequency ablation]. / Osteoidosteom. CT-gesteuerte Bohrexzision und Radiofrequenzablation.

BACKGROUND: The CT-guided therapy of osteoid osteoma instead of older methods such as open resection has the advantage of exact localization of the nidus intraoperatively and exact documentation of its ablation. Another advantage is the less invasive approach. PATIENTS AND METHODS: A total of 52 patients with osteoid osteoma were treated in our institution between 1996 and 2005 either by radiofrequency ablation (n=11) or by percutaneous resection under CT guidance (n=41). Their age was between 7 and 48 years, mean age was 22.3 years, and follow-up was 31.3 months. RESULTS: In all patients (n=52) the osteoid osteoma was successfully treated. In 50 patients the first treatment resulted in long-term success. In two patients the nidus was first missed; they were successfully treated with another operation using the same technique. CONCLUSION: The CT-guided operation of osteoid osteoma made the therapy much easier because of the exact localization and the less invasive approach. This technique can be used analogously to tumor biopsy. The advantage is the exact documentation of the biopsy path and the possibility to take specimens.

Validity and reliability of the PowerTap mobile cycling powermeter when compared with the SRM Device.

The SRM power measuring crank system is nowadays a popular device for cycling power output (PO) measurements in the field and in laboratories. The PowerTap (CycleOps, Madison, USA) is a more recent and less well-known device that allows mobile PO measurements of cycling via the rear wheel hub. The aim of this study is to test the validity and reliability of the PowerTap by comparing it with the most accurate (i.e. the scientific model) of the SRM system. The validity of the PowerTap is tested during i) sub-maximal incremental intensities (ranging from 100 to 420 W) on a treadmill with different pedalling cadences (45 to 120 rpm) and cycling positions (standing and seated) on different grades, ii) a continuous sub-maximal intensity lasting 30 min, iii) a maximal intensity (8-s sprint), and iiii) real road cycling. The reliability is assessed by repeating ten times the sub-maximal incremental and continuous tests. The results show a good validity of the PowerTap during sub-maximal intensities between 100 and 450 W (mean PO difference -1.2 +/- 1.3 %) when it is compared to the scientific SRM model, but less validity for the maximal PO during sprint exercise, where the validity appears to depend on the gear ratio. The reliability of the PowerTap during the sub-maximal intensities is similar to the scientific SRM model (the coefficient of variation is respectively 0.9 to 2.9 % and 0.7 to 2.1 % for PowerTap and SRM). The PowerTap must be considered as a suitable device for PO measurements during sub-maximal real road cycling and in sub-maximal laboratory tests.

Magnetic resonance imaging of anterior cruciate ligament tears: evaluation of standard orthogonal and tailored paracoronal images.

PURPOSE: To evaluate the three standard orthogonal imaging planes and a paracoronal imaging plane for anterior cruciate ligament (ACL) tears. MATERIAL AND METHODS: Ninety patients (91 knees; 29 F and 61 M) aged between 15 and 84 years (mean 36.9 +/- 16.4 years) underwent magnetic resonance imaging (MRI) of the knee prior to arthroscopy. At surgery, 32 knees had an intact ACL, 4 a partial tear, and 55 a complete ACL tear. In all patients, axial, sagittal, coronal, and paracoronal T2-weighted turbo-SE images were acquired. The ACL was classified as intact, partially, or completely torn. Partial and complete tears were combined for statistical evaluation. RESULTS: Partial ACL tears (four cases) were not correctly diagnosed at MRI except in one knee by one observer on coronal images. Sensitivity in detecting ACL tears was 95%/63% (reader1/reader2) in the axial, 93%/95% in the sagittal, 93%/86% in the coronal, and 100%/93% in the paracoronal plane. Specificity was 75%/81% in the axial, 72%/81% in the sagittal, 78%/94% in the coronal, and 78%/88% in the paracoronal plane. CONCLUSION: ACL tears can be diagnosed accurately with each of the standard orthogonal planes. Based on reader confidence and interobserver agreement paracoronal images may be useful in equivocal cases.

Muscular activity level during pedalling is not affected by crank inertial load.

The aim of the present study was to investigate the influence of gear ratio (GR) and thus crank inertial load (CIL), on the activity levels of lower limb muscles. Twelve competitive cyclists performed three randomised trials with their own bicycle equipped with a SRM crankset and mounted on an Axiom ergometer. The power output ( approximately 80% of maximal aerobic power) and the pedalling cadence were kept constant for each subject across all trials but three different GR (low, medium and high) were indirectly obtained for each trial by altering the electromagnetic brake of the ergometer. The low, medium and high GR (mean +/- SD) resulted in CIL of 44 +/- 3.7, 84 +/- 6.5 and 152 +/- 17.9 kg.m(2), respectively. Muscular activity levels of the gluteus maximus (GM), the vastus medialis (VM), the vastus lateralis (VL), the rectus femoris (RF), the medial hamstrings (MHAM), the gastrocnemius (GAS) and the soleus (SOL) muscles were quantified and analysed by mean root mean square (RMS(mean)). The muscular activity levels of the measured lower limb muscles were not significantly affected when the CIL was increased approximately four fold. This suggests that muscular activity levels measured on different cycling ergometers (with different GR and flywheel inertia) can be compared among each other, as they are not influenced by CIL.

EMG activity does not change during a time trial in competitive cyclists.

The purpose of the present study was to measure the electromyographic (EMG) activity of four lower limb muscles and the propulsive torque during a cycling time-trial (TT). Nine competitive cyclists (V.O (2max): 73.8 +/- 5.3 ml . min (-1) . kg (-1)) performed two tests separated over a one-week period on a friction-load cycle ergometer equipped with a SRM crankset scientific system: 1) a continuous incremental test for the determination of the peak power output (PPO); and 2) a 30-min TT test at a self-selected work intensity. The EMG activity of the vastus medialis (VM), the rectus femoris (RF), the biceps femoris (BF), and the gastrocnemius medialis (GAS), and the propulsive torque were recorded every 5 min for 10 s. There was no time effect on the power output, the pedalling cadence, and the mean propulsive torque. The EMG activity of the VM and the RF muscles was unchanged during the TT (p > 0.05). The EMG activity of the two knee flexor muscles (BF and GAS) tended to increase with time but it was not significant (p > 0.05). The EMG/torque of the VM and the RF muscles tended to decrease with time but it was not significant (p > 0.05). The lack of increase in the EMG activity of the four investigated muscles seems to indicate that the subjects performed the TT test at a muscular work steady-state.