Effect of Energy Expenditure and Training Status on Leptin Response to Sub-Maximal Cycling

We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR) and 7 untrained (UTR) subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively) were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP). Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively. [Lep] was related to body fat percentage and body fat mass in TR (r = 0. 84, p < 0.05 and r = 0.93, p < 0.01) and in UTR (r = 0.89, p < 0.01 and r = 0.92, p < 0. 01, respectively). [Lep] did not change significantly during both protocols for both groups but was lower (p < 0.05) in all sampling in TR when compared to UTR. Plasma [I] decreased (p < 0.01) and [GH] increased (p < 0.01) significantly during both SP and PP and these hormones remained lower (I: p < 0.01) and higher (GH: p < 0.01) than pre-exercise levels after a 2-h recovery period, returning to base-line at 24-h recovery. Plasma [La] increased (p < 0.01) during both protocols for TR and UTR. There was no significant change in [C] and [G] during and after both protocols for all subjects. It is concluded that 1) leptin is not sensitive to acute short or prolonged sub-maximal exercises (with energy expenditure under 800 kcal) in volleyball/ anaerobically trained athletes as in untrained subjects, 2) volleyball athletes showed significantly lower resting and exercise leptin response with respect to untrained subjects and 3) it appears that in these anaerobically trained athletes leptin response to exercise is more sensitive to the level of energy expenditure than hormonal or metabolic modifications induced by acute exercise.

Key points

• Trials concerning acute exercise and leptin indicated discrepant results.
• Acute exercise with energy expenditure higher than 800 kcal can decrease leptinemia.
• Elite volleyball players presented decreased leptin levels than untrained subjects.

Key words: Hormones, anaerobic training, acute exercise, body fat.     

Effects of Active Versus Passive Recovery on Power Output During Repeated Bouts of Short Term,High Intensity Exercise

ATP repletion following exhaustive exercise is approximated to be 90-95% complete in 3 minutes, and is crucial in the performance of short duration, high intensity work. Few studies appear to have used this 3-minute interval in the investigation of recovery modes, blood lactate accumulation and power output. Thus, our aim was to investigate changes in peak power (PP), average power (AP) and blood lactate during repeated bouts of high intensity, short duration cycling, comprising active and passive recovery modes lasting 3 minutes. Seven male cyclists (age 21.8±3.3 yrs, mass 73.0±3.8kgs, height 177.3±3.4cm) performed both an active (3 min at 80rpm & 1kg resistance) and a passive recovery (no work between bouts) protocol. Following a warm-up, subjects performed six 15-second maximal sprints against a fixed workload of 5.5kg. Mean PP across the six trials was 775±11.2Watts (W) and 772±33.4W for active and passive protocols respectively; whereas mean AP was 671±26.4W and 664±10.0W, respectively. Neither was significantly different. There was a significant difference within trials for both peak power and average power (p<0.05), with both values decreasing over time. However, the decrease was significantly smaller for both PP and AP values during the active recovery protocol (p<0.05). In the current study, variation in power output cannot be explained by lactate values, as values did not differ between the active and passive protocol (p=0.37). Lactate values did differ significantly between trials within protocols (p<0.05). The results of this study suggest that an active recovery of 3 minutes between high intensity, short duration exercise bouts significantly increases PP and AP compared to a passive recovery, irrespective of changes in blood lactate levels.Key words: Anaerobic power, light exercise, lactate, power output     

Increased Skeletal Muscle Capillarization Independently Enhances Insulin Sensitivity in Older Adults After Exercise Training and Detraining

Intramuscular signaling and glucose transport mechanisms contribute to improvements in insulin sensitivity after aerobic exercise training. This study tested the hypothesis that increases in skeletal muscle capillary density (CD) also contribute to exercise-induced improvements in whole-body insulin sensitivity (insulin-stimulated glucose uptake per unit plasma insulin [M/I]) independent of other mechanisms. The study design included a 6-month aerobic exercise training period followed by a 2-week detraining period to eliminate short-term effects of exercise on intramuscular signaling and glucose transport. Before and after exercise training and detraining, 12 previously sedentary older (65 ± 3 years) men and women underwent research tests, including hyperinsulinemic-euglycemic clamps and vastus lateralis biopsies. Exercise training increased Vo_2max (2.2 ± 0.2 vs. 2.5 ± 0.2 L/min), CD (313 ± 13 vs. 349 ± 18 capillaries/mm²), and M/I (0.041 ± 0.005 vs. 0.051 ± 0.007 μmol/kg fat-free mass/min) (P < 0.05 for all). Exercise training also increased the insulin activation of glycogen synthase by 60%, GLUT4 expression by 16%, and 5′ AMPK-α1 expression by 21%, but these reverted to baseline levels after detraining. Conversely, CD and M/I remained 15% and 18% higher after detraining, respectively (P < 0.05), and the changes in M/I (detraining minus baseline) correlated directly with changes in CD in regression analysis (partial r = 0.70; P = 0.02). These results suggest that an increase in CD is one mechanism contributing to sustained improvements in glucose metabolism after aerobic exercise training.     

Percutaneous mesh-container-plasty for osteoporotic thoracolumbar burst fractures: A prospective,nonrandomized comparative study

ObjectiveThis study aimed to compare the clinical and radiological results of percutaneous mesh-container-plasty (PMCP) versus percutaneous kyphoplasty (PKP) in the treatment of osteoporotic thoracolumbar burst fractures.MethodsA prospective study of 122 patients with osteoporotic thoracolumbar burst fractures was conducted. The patients were nonrandomly assigned to receive PKP (62; 16 men, 46 women) and PMCP (60; 14 men, 46 women). The epidemiological data, surgical outcomes, and clinical and radiological features were compared between the 2 groups. Cement leakage, height restoration, deformity correction, canal compromise, and cement distribution were calculated from the radiographs. Visual pain analog scale (VAS), the Oswestry disability index (ODI), and short-form 36 health survey domains role physical (SF-36 rp) and bodily pain (SF-36 bp) were calculated before surgery and immediately and 2 years after surgery.ResultsAlthough VAS, ODI, SF-36 bp, and SF-36 rp scores improved from 7 (6–9), 71.28±16.38, 22 (0–32), and 25 (0–50) preoperatively to 2 (1–3), 20.02±8.97, 84 (84–84), and 75 (75–100) immediately postoperatively in the PMCP group (p<0.05) and from 7 (6–8), 71.40±13.52, 22 (10.5–31.75), and 25 (0–50) preoperatively to 2 (1–3), 21.78±11.21, 84 (84–84), and 75 (75–100) immediately postoperatively in the PKP group (p<0.05), there was no difference between the 2 groups. The mean cost in the PKP group was less than that in the PMCP group ($5109±231 vs. $6699±201, p<0.05). Anterior, middle, and posterior vertebral body height ratios in the PMCP group were greater than those in the PKP group postoperatively (88.44%±3.76% vs. 81.10%±11.78%, 86.15%±3.50% vs. 82.30%±11.02%, and 93.91%±3.01% vs. 91.43%±6.71%, respectively, p<0.05). The Cobb angle in the PMCP group was lower than that in the PKP group postoperatively (6.67°±4.39° vs. 8.99°±4.06°, p<0.05). Cement distribution in the PMCP group was higher than that in the PKP group (30.48%±5.62% vs. 27.18%±4.87%, p<0.05). Cement leakage was observed to be lesser in the PMCP group (2/60) than in the PKP group (10 vs. 62, p<0.05).ConclusionBoth PKP and PMCP treatments seem to have significant ability in pain relief and functional recovery. Despite its higher cost, PMCP treatment may have a better inhibition ability of cement leakage, cement distribution, height restoration, and improvement in segmental kyphosis than PKP treatment for osteoporotic thoracolumbar burst fractures.Level of EvidenceLevel II, Therapeutic Study     

Hemodynamic and Lactic Acid Responses to Proprioceptive Neuromuscular Facilitation Exercise

The hemodynamic and metabolic responses to proprioceptive neuromuscular facilitation (PNF) exercise were examined in 32 male university students (aged 19-28 years). Ten repetitions of PNF exercises were applied to the subjects’ dominant upper extremities in the following order: as an agonist pattern flexion, adduction and external rotation; and as an antagonist pattern extension, abduction and internal rotation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), double product (DP), and blood lactate concentration (La) were determined before, immediately after, and at 1^st, 3^rd, and 5^th minutes after PNF exercise. A one-way ANOVA with repeated measures indicated significant differences in HR, SBP, DBP, DP and La immediately after PNF exercise. HR increased from 81 (±10) to 108 (±15) b·min^-1 (p < 0.01), SBP increased from 117 (±10) to 125 (±11) mmHg (p < 0.01), DBP increased from 71 (±10) to 75 (±8) mmHg (p < 0.01), DP increased from 96 (±16) to 135 (±24) (p < 0.01), and La increased from 0.69 (±0.31) to 3.99 (±14.63) mmol·L^-1 (p < 0.01). Thus PNF exercise resulted in increased hemodynamic responses and blood lactate concentration that indicate a high strain on the cardiovascular system and anaerobic metabolism in healthy subjects.

Key Points

• PNF exercises resulted in increased hemodynamic responses.
• Repeated PNF exercises resulted in an increased blood lactate concentration.

Key words: Heart rate, systolic blood pressure, diastolic blood pressure, double product, PNF     

A Multi-Station Proprioceptive Exercise Program in Patients with Bilateral Knee Osteoarthrosis: Functional Capacity,Pain and Sensoriomotor Function. A Randomized Controlled Trial

We investigated the effects of a multi-station proprioceptive exercise program on functional capacity, perceived knee pain, and sensoriomotor function. Twenty-two patients (aged 41-75 years) with grade 2-3 bilateral knee osteoarthrosis were randomly assigned to two groups: treatment (TR; n = 12) and non-treatment (NONTR; n = 10). TR performed 11 different balance/coordination and proprioception exercises, twice a week for 6 weeks. Functional capacity and perceived knee pain during rest and physical activity was measured. Also knee position sense, kinaesthesia, postural control, isometric and isokinetic knee strength (at 60, 120 and 180°·s^-1) measures were taken at baseline and after 6 weeks of training. There was no significant difference in any of the tested variables between TR and NONTR before the intervention period. In TR perceived knee pain during daily activities and functional tests was lessened following the exercise program (p < 0.05). Perceived knee pain was also lower in TR vs. NONTR after training (p < 0.05). The time for rising from a chair, stair climbing and descending improved in TR (p < 0.05) and these values were faster compared with NONTR after training (p < 0.05). Joint position sense (degrees) for active and passive tests and for weight bearing tests improved in TR (p < 0.05) and the values were lower compared with NONTR after training (p < 0.05). Postural control (‘eyes closed’) also improved for single leg and tandem tests in TR (p < 0.01) and these values were higher compared with NONTR after training. The isometric quadriceps strength of TR improved (p < 0.05) but the values were not significantly different compared with NONTR after training. There was no change in isokinetic strength for TR and NONTR after the training period. The results suggest that using a multi-station proprioceptive exercise program it is possible to improve postural control, functional capacity and decrease perceived knee pain in patients with bilateral knee osteoarthrosis.

Key Points

• It is possible to improve postural control, functional capacity and decrease perceived knee pain in patients with bilateral knee osteoarthrosis with a pure proprioceptive/ balance exercise program used in the present study.
• The exercise regime used in the present study was as effective as previous studies, but of much shorter duration and utilized unsophisticated, inexpensive equipment which is available in most physiotherapy departments.
• Therefore, the incorporation of this exercise program into clinical practice is readily feasible.

Key Words: Osteoarthrosis, proprioception, balance, perceived knee pain, function     

Platelet-rich Concentrates Differentially Release Growth Factors and Induce Cell Migration In Vitro

Background

Platelet-rich concentrates are used as a source of growth factors to improve the healing process. The diverse preparation protocols and the gaps in knowledge of their biological properties complicate the interpretation of clinical results.

Questions/purposes

In this study we aimed to (1) analyze the concentration and kinetics of growth factors released from leukocyte- and platelet-rich fibrin (L-PRF), leukocyte- and platelet-rich plasma (L-PRP), and natural blood clot during in vitro culture; (2) investigate the migration of mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as a functional response to the factors released; and (3) uncover correlations between individual growth factors with the initial platelet/leukocyte counts or the induced cell migration.

Methods

L-PRF, L-PRP, and natural blood clot prepared from 11 donors were cultured in vitro for 28 days and media supernatants collected after 8 hours and 1, 3, 7, 14, and 28 days. Released transforming growth factor β1 (TGF-β1), vascular endothelial growth factor (VEGF), insulin growth factor (IGF-1), platelet-derived growth factor AB (PDGF-AB), and interleukin-1β (IL-1β) were measured in the supernatants with enzyme-linked immunosorbent assay. Migration of MSC and HUVEC induced by the supernatants was evaluated in Boyden chambers.

Results

More TGF-ß1 was released (mean ± SD in pg/mL of blood) from L-PRF (37,796 ± 5492) compared with L-PRP (23,738 ± 6848; p < 0.001) and blood clot (3739 ± 4690; p < 0.001), whereas more VEGF and IL-1ß were released from blood clot (1933 ± 704 and 2053 ± 908, respectively) compared with both L-PRP (642 ± 208; p < 0.001 and 273 ± 386; p < 0.001, respectively) and L-PRF (852 ± 376; p < 0.001 and 65 ± 56, p < 0.001, respectively). No differences were observed in IGF-1 and PDGF-AB released from any of the concentrates. TGF-β1 release peaked at Day 7 in L-PRF and at 8 hours and Day 7 in L-PRP and 8 hours and Day 14 in blood clot. In all concentrates, main release of VEGF occurred between 3 and 7 days and of IL-1β between Days 1 and 7. IGF-1 and PDGF-AB were released until Day 1 in L-PRP and blood clot, in contrast to sustained release over the first 3 days in L-PRF. The strongest migration of MSC occurred in response to L-PRF, and more HUVEC migration was seen in L-PRF and blood clot compared with L-PRP. TGF-β1 correlated with initial platelet counts in L-PRF (Pearson r = 0.66, p = 0.0273) and initial leukocyte counts in L-PRP (Pearson r = 0.83, p = 0.0016). A positive correlation of IL-1β on migration of MSC and HUVEC was revealed (Pearson r = 0.16, p = 0.0208; Pearson r = 0.31, p < 0.001).

Conclusions

In comparison to L-PRP, L-PRF had higher amounts of released TGF-β1, a long-term release of growth factors, and stronger induction of cell migration. Future preclinical studies should confirm these data in a defined injury model.

Clinical Relevance

By characterizing the biologic properties of different platelet concentrates in vitro, we may gain a better understanding of their clinical effects and develop guidelines for specific future applications.     

Comparison of two platelet activation markers using flow cytometry after in vitro shear stress exposure of whole human blood

Platelet activation is the initiating step to thromboembolic complications in blood‐contacting medical devices. Currently, there are no widely accepted testing protocols or relevant metrics to assess platelet activation during the in vitro evaluation of new medical devices. In this article, two commonly used platelet activation marker antibodies, CD62P (platelet surface P‐selectin) and PAC1 (activated GP IIb/IIIa), were evaluated using flow cytometry. Anticoagulant citrate dextrose solution A (ACDA) and heparin anticoagulated human blood from healthy donors were separately exposed to shear stresses of 0, 10, 15, and 20 Pa for 120 s using a cone‐plate rheometer model, and immediately mixed with the platelet marker antibodies for analysis. To monitor for changes in platelet reactivity between donors and over time, blood samples were also evaluated after exposure to 0, 2, and 20 µM of adenosine diphosphate (ADP). Following ADP stimulation, the percentage of both CD62P and PAC1 positive platelets increased in a dose dependent fashion, even 8 h after the blood was collected. After shear stress stimulation, both CD62P and PAC1 positive platelets increased significantly at shear stress levels of 15 and 20 Pa when ACDA was used as the anticoagulant. However, for heparinized blood, the PAC1 positive platelets decreased with increasing shear stress, while the CD62P positive platelets increased. Besides the anticoagulant effect, the platelet staining buffer also impacted PAC1 response, but had little effect on CD62P positive platelets. These data suggest that CD62P is a more reliable marker compared with PAC1 for measuring shear‐dependent platelet activation and it has the potential for use during in vitro medical device testing.     

Long-Term Hemodynamic Effects of Portocaval Shunt and Sugiura Procedure in Patients with Cirrhosis

Systemic and splanchnic hemodynamics were studied before and six months after a portal systemic shunt (n=6) or a Sugiura procedure (n=9) in 15 patients with cirrhosis and a past history of variceal bleeding. Hepatic blood flow was estimated by hepatic extraction and clearance of continuous indocyanine green infusion. Azygos blood flow was measured with a continuous thermodilution catheter. After portocaval shunt, the cardiac index increased significantly from 4.0±1.4 to 5.4±0.8 l/min m2 (p<0.05), the hepatic venous pressure gradient and hepatic blood flow were significantly decreased from 21±3 to 13±5 mm Hg (p<0.05) and from 1.20±0.35 to 0.37±0.16 l/min (p<0.05) respectively. The decrease in azygos blood flow was not significant (0.51±0.31 vs 0.25±0.33 l/min; p=0.1). After Sugiura procedure, there was no significant change in cardiac index, hepatic venous pressure gradient, hepatic blood flow or azygos blood flow. This is the first study to show the long-term maintenance of splanchnic and systemic hemodynamics in patients with cirrhosis after Sugiura procedure. The absence of long-term hemodynamic alterations could explain the absence of encephalopathy after this procedure.     

Acute Effects of Two Different Warm-Up Protocols on Flexibility and Lower Limb Explosive Performance in Male and Female High Level Athletes

This study examined the effects of two different warm-up protocols on lower limb power and flexibility in high level athletes. Twenty international level fencers (10 males and 10 females) performed two warm-up protocols that included 5-min light jogging and either short (15s) or long (45s) static stretching exercises for each of the main leg muscle groups (quadriceps, hamstrings and triceps surae), followed by either 3 sets of 3 (short stretching treatment), or 3 sets of 5 tuck jumps (long stretching treatment), in a randomized crossover design with one week between treatments. Hip joint flexion was measured with a Lafayette goniometer before and after the 5-min warm-up, after stretching and 8 min after the tuck jumps, while counter movement jump (CMJ) performance was evaluated by an Ergojump contact platform, before and after the stretching treatment, as well as immediately after and 8 minutes after the tuck jumps. Three way ANOVA (condition, time, gender) revealed significant time (p < 0.001) and gender (p < 0.001) main effects for hip joint flexion, with no interaction between factors. Flexibility increased by 6. 8 ± 1.1% (p < 0.01) after warm-up and by another 5.8 ± 1.6% (p < 0.01) after stretching, while it remained increased 8 min after the tuck jumps. Women had greater ROM compared with men at all time points (125 ± 8° vs. 94 ± 4° p<0.01 at baseline), but the pattern of change in hip flexibility was not different between genders. CMJ performance was greater in men compared with women at all time points (38.2 ± 1.9 cm vs. 29.8 ± 1.2 cm p < 0.01 at baseline), but the percentage of change CMJ performance was not different between genders. CMJ performance remained unchanged throughout the short stretching protocol, while it decreased by 5.5 ± 0.9% (p < 0.01) after stretching in the long stretching protocol However, 8 min after the tuck jumps, CMJ performance was not different from the baseline value (p = 0.075). In conclusion, lower limb power may be decreased after long periods of stretching, but performance of explosive exercises may reverse this phenomenon.

Key points

• Stretching of the main leg muscle groups for 45 s results in a relatively large decrease (by 5.5%) in subsequent jumping performance
• Stretching of the main leg muscle groups for only 15 s results in an increase in flexibility similar to that of the longer duration stretching (by 12.6%), with no change in subsequent jumping performance
• Performance of a PAP exercise such as tuck jumps may reverse the negative effects of long duration stretching on leg muscle power. However, jumping performance is not increased above baseline
• Speed/power athletes should be advised against using long duration stretching. The number of repetitions of a PAP exercise such as the tuck jumps, should be further examined in order to induce an increase in explosive performance during competition

Key words: Countermovement jump, stretching, post-activation potentiation, fencing     

Results of Pancreatic Blood Shunting into the Systemic Blood Flow in Insulin-Dependent Diabetics

A new surgical method of treating patients with unstable insulin-dependent diabetes (IDD) has been developed-that of surgically shunting pancreatic blood into the systemic blood flow with the purpose of creating a more optimal interaction of subcutaneously administered insulin and pancreas-secreted glucagon.The long term results of the operation depend on the patency of a splenorenal anastomosis. This has been studied by following up 137 patients over periods from half a year to three years. Anastomotic patency was determined by renal and splenic venography and celiacy arteriography, which revealed a patent anastomosis in 114 patients, and an obliterated one in 23.Patients with patent anastomoses showed a lowering of glycosylated hemoglobin (HbA_lc) from 13.3±0.03% to 9.3±0.6%, p<0.05, a decrease of the injected insulin dose from 0.97±0.04 to 0.72±0.03 U/ kg, p<0.05, disappearance or considerable abatement of pain in the lower extremities, and of hypoglycemia. Improvement of clinical status was accompanied by an increase of glucagon in the systemic blood stream from 60.8±10.1 to 91.5±9.4 pg/ml, p<0.05, a rise of tissue oxygen pressure, PO₂, from 49.2±2.4 to 58.1±1.9 mm Hg, p<0.05. In patients with oblivious anastomoses postoperative HbA_lc levels did not change from preoperative values: 12.9±0.4% and 12.8±0.7%, p<0.05, respectively; the insulin dose remained the same-0.91 ±0.07 U/kg and 0.85±0.07 U/kg, p<0.05, no rise of the systemic blood glucagon content was noted, and former complaints continued.The suggested method is not an alternative for insulin therapy, but considerably enhances its potential.     

Relationship Between the MTI Accelerometer (Actigraph) Counts and Running Speed During Continuous and Intermittent Exercise

This study was designed to investigate the relationship between Actigraph counts and running speed; and to describe differences due to accelerometer position on the body and due to exercise modality. Eleven physical education students (age, 25.1 ± 3.7 years; height, 1.73 ± 0.10 m; body mass, 70.8 ± 10.8 kg) completed two exhaustive exercise tests (continuous and intermittent), with MTI accelerometers mounted both at the hip and ankle. Exercise consisted of running for 3-min at incremental speeds until volitional exhaustion. During both exercise tests, the relationship between the ActiGraph outputs worn at the hip and speed was linear in the range 1.1 - 3.3 m·s^-1 (r² = 0.94 and 0.95, p < 0.01 for continuous and intermittent exercise respectively). A coefficient of determination of r² = 0.97 (p < 0.01) was found with ankle wearing from walking, jogging and running at high speeds. There was a body placement effect at all absolute speeds (p < 0.01); but no exercise effect on accelerometer counts and no interaction between placement and exercise (p> 0.05). The ActiGraph seems to be a reliable tool for estimating a wide range of activity or exercise intensities. An ActiGraph worn at the ankle may be more appropriate to reflect normal human movement.

Key Points

• Actigraph counts are not influenced by the type of activity.
• The levelling off of Actigraph output depends mainly on its location on the body, and does not reflect a lack of sensivity at higher speeds.
• The ActiGraph can be an alternative tool to estimate activity intensity in various conditions.

Key words: Physical activity, joint kinematics, hip, ankle     

Whole-body Vibration at Thoracic Resonance Induces Sustained Pain and Widespread Cervical Neuroinflammation in the Rat

Background

Whole-body vibration (WBV) is associated with back and neck pain in military personnel and civilians. However, the role of vibration frequency and the physiological mechanisms involved in pain symptoms are unknown.

Questions/purposes

This study asked the following questions: (1) What is the resonance frequency of the rat spine for WBV along the spinal axis, and how does frequency of WBV alter the extent of spinal compression/extension? (2) Does a single WBV exposure at resonance induce pain that is sustained? (3) Does WBV at resonance alter the protein kinase C epsilon (PKCε) response in the dorsal root ganglia (DRG)? (4) Does WBV at resonance alter expression of calcitonin gene-related peptide (CGRP) in the spinal dorsal horn? (5) Does WBV at resonance alter the spinal neuroimmune responses that regulate pain?

Methods

Resonance of the rat (410 ± 34 g, n = 9) was measured by imposing WBV at frequencies from 3 to 15 Hz. Separate groups (317 ± 20 g, n = 10/treatment) underwent WBV at resonance (8 Hz) or at a nonresonant frequency (15 Hz). Behavioral sensitivity was assessed throughout to measure pain, and PKCε in the DRG was quantified as well as spinal CGRP, glial activation, and cytokine levels at Day 14.

Results

Accelerometer-based thoracic transmissibility peaks at 8 Hz (1.86 ± 0.19) and 9 Hz (1.95 ± 0.19, mean difference [MD] 0.290 ± 0.266, p < 0.03), whereas the video-based thoracic transmissibility peaks at 8 Hz (1.90 ± 0.27), 9 Hz (2.07 ± 0.20), and 10 Hz (1.80 ± 0.25, MD 0.359 ± 0.284, p < 0.01). WBV at 8 Hz produces more cervical extension (0.745 ± 0.582 mm, MD 0.242 ± 0.214, p < 0.03) and compression (0.870 ± 0.676 mm, MD 0.326 ± 0.261, p < 0.02) than 15 Hz (extension, 0.503 ± 0.279 mm; compression, 0.544 ± 0.400 mm). Pain is longer lasting (through Day 14) and more robust (p < 0.01) after WBV at the resonant frequency (8 Hz) compared with 15 Hz WBV. PKCε in the nociceptors of the DRG increases according to the severity of WBV with greatest increases after 8 Hz WBV (p < 0.03). However, spinal CGRP, cytokines, and glial activation are only evident after painful WBV at resonance.

Conclusions

WBV at resonance produces long-lasting pain and widespread activation of a host of nociceptive and neuroimmune responses as compared with WBV at a nonresonance condition. Based on this work, future investigations into the temporal and regional neuroimmune response to resonant WBV in both genders would be useful.

Clinical Relevance

Although WBV is a major issue affecting the military population, there is little insight about its mechanisms of injury and pain. The neuroimmune responses produced by WBV are similar to other pain states, suggesting that pain from WBV may be mediated by similar mechanisms as other neuropathic pain conditions. This mechanistic insight suggests WBV-induced injury and pain may be tempered by antiinflammatory intervention.

Electronic supplementary material

The online version of this article (doi:10.1007/s11999-015-4315-9) contains supplementary material, which is available to authorized users.     

Similar Anti-Inflammatory Acute Responses from Moderate-Intensity Continuous and High-Intensity Intermittent Exercise

The purpose of this study was to compare the effect of high-intensity intermittent exercise (HIIE) versus volume matched steady state exercise (SSE) on inflammatory and metabolic responses. Eight physically active male subjects completed two experimental sessions, a 5-km run on a treadmill either continuously (70% vVO₂max) or intermittently (1:1 min at vVO₂max). Blood samples were collected at rest, immediately, 30 and 60 minutes after the exercise session. Blood was analyzed for glucose, non-ester fatty acid (NEFA), uric acid, lactate, cortisol, and cytokines (IL-6, IL-10 and TNF-α) levels. The lactate levels exhibited higher values immediately post-exercise than at rest (HIIE 1.34 ± 0.24 to 7.11 ± 2.85, and SSE 1.35 ± 0.14 to 4.06±1.60 mmol·L^-1, p < 0.05), but HIIE promoted higher values than SSE (p < 0.05); the NEFA levels were higher immediately post-exercise than at rest only in the SSE condition (0.71 ± 0.04 to 0.82±0.09 mEq/L, respectively, p < 0.05), yet, SSE promoted higher values than HIIE immediately after exercise (HIIE 0.72±0.03 vs SSE 0.82±0.09 mEq·L^-1, p < 0.05). Glucose and uric acid levels did not show changes under the different conditions (p > 0.05). Cortisol, IL-6, IL-10 and TNF-α levels showed time-dependent changes under the different conditions (p < 0.05), however, the area under the curve of TNF-α in the SSE were higher than HIIE (p < 0.05), and the area under the curve of IL-6 in the HIIE showed higher values than SSE (p < 0.05). In addition, both exercise conditions promote increased IL-10 levels and IL-10/TNF-α ratio (p < 0.05). In conclusion, our results demonstrated that both exercise protocols, when volume is matched, promote similar inflammatory responses, leading to an anti-inflammatory status; however, the metabolic responses are different.

Key points

• Metabolic contribution of both exercise, HIIE and SSE, was different.
• Both protocols leading to an anti-inflammatory status.
• HIIE induce a higher energy expenditure take into account total session duration.

Key words: High intensity intermittent exercise, steady state exercise, metabolism, inflammation, energy expenditure, cytokines     

Twelve Percent of Hips With a Primary Cam Deformity Exhibit a Slip-like Morphology Resembling Sequelae of Slipped Capital Femoral Epiphysis

BackgroundIn some hips with cam-type femoroacetabular impingement (FAI), we observed a morphology resembling a more subtle form of slipped capital femoral epiphysis (SCFE). Theoretically, the morphology in these hips should differ from hips with a primary cam-type deformity.Questions/purposesWe asked if (1) head-neck offset; (2) epiphyseal angle; and (3) tilt angle differ among hips with a slip-like morphology, idiopathic cam, hips after in situ pinning of SCFE, and normal hips; and (4) what is the prevalence of a slip-like morphology among cam-type hips?MethodsWe retrospectively compared the three-dimensional anatomy of hips with a slip-like morphology (29 hips), in situ pinning for SCFE (eight hips), idiopathic cam deformity (171 hips), and 30 normal hips using radial MRI arthrography. Normal hips were derived from 17 asymptomatic volunteers. All other hips were recruited from a series of 277 hips (243 patients) seen at a specialized academic hip center between 2006 and 2010. Forty-one hips with isolated pincer deformity were excluded. Thirty-six of 236 hips had a known cause of cam impingement (secondary cam), including eight hips after in situ pinning of SCFE (postslip group). The 200 hips with a primary cam were separated in hips with a slip-like morphology (combination of positive fovea sign [if the neck axis did not intersect with the fovea capitis] and a tilt angle [between the neck axis and perpendicular to the basis of the epiphysis] exceeding 4°) and hips with an idiopathic cam. We evaluated offset ratio, epiphyseal angle (angle between the neck axis and line connecting the center of the femoral head and the point where the physis meets the articular surface), and tilt angle circumferentially around the femoral head-neck axis. Prevalence of slip-like morphology was determined based on the total of 236 hips with cam deformities.ResultsOffset ratio was decreased anterosuperiorly in idiopathic cam, slip-like, and postslip (eg, 1 o’clock position with a mean offset ranging from 0.00 to 0.14; p < 0.001 for all groups) compared with normal hips (0.25 ± 0.06 [95% confidence interval, 0.13–0.37]) and increased posteroinferiorly in slip-like (eg, 8 o’clock position, 0.5 ± 0.09 [0.32–0.68]; p < 0.001) and postslip groups (0.55 ± 0.12 [0.32–0.78]; p < 0.001) and did not differ in idiopathic cam (0.32 ± 0.09 [0.15–0.49]; p = 0.323) compared with normal (0.31 ± 0.07 [0.18–0.44]) groups. Epiphyseal angle was increased anterosuperiorly in the slip-like (eg, 1 o’clock position, 70° ± 9° [51°–88°]; p < 0.001) and postslip groups (75° ± 13° [49°–100°]; p = 0.008) and decreased in idiopathic cam (50° ± 8° [35°–65°]; p < 0.001) compared with normal hips (58° ± 8° [43°–74°]). Posteroinferiorly, epiphyseal angle was decreased in slip-like (eg, 8 o’clock position, 54° ± 10° [34°–74°]; p < 0.001) and postslip (44° ± 11° [23°–65°]; p < 0.001) groups and did not differ in idiopathic cam (76° ± 8° [61°–91°]; p = 0.099) compared with normal (73° ± 7° [59°–88°]) groups. Tilt angle increased in slip-like (eg, 2/8 o’clock position, 14° ± 8° [−1° to 30°]; p < 0.001) and postslip hips (29° ± 10° [9°–48°]; p < 0.001) and decreased in hips with idiopathic cam (−7° ± 5° [−17° to 4°]; p < 0.001) compared with normal (−1° ± 5° [−10° to 8°]) hips. The prevalence of a slip-like morphology was 12%.ConclusionsThe slip-like morphology is the second most frequent pathomorphology in hips with primary cam deformity. MRI arthrography of the hip allows identifying a slip-like morphology, which resembles hips after in situ pinning of SCFE and distinctly differs from hips with idiopathic cam. These results support previous studies reporting that SCFE might be a risk factor for cam-type FAI.

Level of Evidence

Level III, prognostic study.

Electronic supplementary material

The online version of this article (doi:10.1007/s11999-014-4068-x) contains supplementary material, which is available to authorized users.     

Cryptogenic fibrosing alveolitis: clinical features and their influence on survival

A retrospective analysis of 220 cases fulfilling criteria for cryptogenic fibrosing alveolitis (CFA) attending the Brompton Hospital between 1955 and 1973 has been carried out and patients have been followed for between four and 21 years. The frequency of various clinical features confirms previous reports. The 2: 1 male preponderance was similar in all age groups. The mean age at presentation was 54 years ± 12 SD; 202 (92%) of the patients presented with dyspnoea, the severity of which was related to the reduction in vital capacity (p<0·003) and to the radiographic profusion score (p<0·01) but not to its duration. Twenty-one per cent of the 220 had joint symptoms, 10% having clinical rheumatoid arthritis. Eleven per cent had other types of connective tissue disorder. In all, 30% had polyarthritis or other immunological disorders and 70% lone CFA. Apart from an increase in rheumatoid factor in those with polyarthritis, there were no other clinical or survival differences between those with and without associated immunological disease. Forty-five per cent of 205 subjects had antinuclear antibody, and this occurred equally in those with and without associated connective tissue disorders. One hundred and forty-seven initial radiographs were available for reclassification using the ILO/UC system and only three were normal. Small rounded opacities were seen in 16% and small irregular opacities in 84%. Pleural changes were uncommon. Histological confirmation had been obtained in 118 patients and material was still available for review using a semiquantitative analysis in 68 (biopsy 42 and necropsy 26). Of the biopsies one could be classified as desquamative interstitial pneumonia (DIP) and 17 as endstage fibrosis; the other 24 showed a mixed cellular and fibrotic pattern. The necropsy material showed much greater fibrosis and less acute inflammatory cellularity in spite of an interval between onset of symptoms and death of less than four years in 21 of 26 patients. One hundred and fifty-six patients have died (mean survival 3·2 years). Eleven (5%) are believed to be alive but have been lost to follow-up. Fifty-five per cent of deaths were attributable directly or indirectly to CFA. There was also an excess of deaths from cardiovascular disease and lung cancer. Using a life-table analysis and a log rank test, longer survival was seen in younger patients (p<0·001) and women (p<0·01). After correction for age and sex, lesser grades of dyspnoea (p<0·03) and lesser radiographic abnormality (p<0·001), absence of right axis deviation (p<0·001), and a higher Pao₂ (p<0·01) also related to longer survival. Subjects with more cellular histology also survived longer (p<0·02). Factors having no influence on survival included duration of dyspnoea before presentation, degree of reduction of FEV₁, FVC, and TLC, the presence of “connective tissue” disorders, autoantibodies, smoking history, cough, sputum, crackles, clubbing, ESR, or immunoglobulins.     

Effect of lignocaine, sodium cromoglycate, and ipratropium bromide in exercise-induced asthma

Eight patients with exercise-induced asthma participated in a single-blind trial comparing the protective effects of inhaled lignocaine (estimated dose 48 mg), sodium cromoglycate (estimated dose 12 mg), and ipratropium bromide (estimated dose 120 μg). Saline was used as control. Effects were assessed from the mean maximal percentage fall in forced expiratory volume in one second (FEV₁) and maximal mid-expiratory flow rates (MMFR) after they had run on a treadmill for eight minutes. There was no significant change in baseline FEV₁ or MMFR before each agent was given. Saline, lignocaine, and sodium cromoglycate did not alter the mean baseline FEV₁ or MMFR significantly. Ipratropium caused bronchodilatation with an increase of 16·3% in the mean FEV₁ (p<0·001) and of 43·4% in the mean MMFR (p<0·05). After exercise the maximal percentage falls in FEV₁ (means and SEM) after saline, lignocaine, sodium cromoglycate, and ipratropium bromide were 38·1% (5·0), 34·5% (6·1), 11·3% (3·7), and 19·3% (7·4) respectively. Similarly, the mean maximal falls in MMFR after saline, lignocaine, sodium cromoglycate, and ipratropium bromide were 54·4% (5·2), 52·9% (7·7), 23·6% (6·6), and 32·1% (10·5) respectively. The inhibitory effects of sodium cromoglycate and ipratropium bromide were significant whereas lignocaine failed to produce an effect. These results suggest that mediator release is an important factor in exercise-induced asthma and that in some patients the effects of the mediators may be on the postsynaptic muscarinic receptors. Local anaesthesia of sensory vagal receptors, on the other hand, does not prevent exercise asthma and these receptors do not appear to have any important role in exercise-induced bronchoconstriction.     

Myoelectric Alterations after Voluntary Induced High - and Low - Frequency Fatigue

The aim of the study was to find whether voluntary induced high- and low-frequency peripheral fatigue exhibit specific alteration in surface EMG signal (SEMG) during evoked and maximum voluntary contractions. Ten male students of physical education performed 60 s long stretch-shortening cycle (SSC) exercise with maximal intensity and 30 s long concentric (CON) exercise with maximal intensity. To verify voluntary induced peripheral fatigue, knee torques during low- (T₂₀) and high-frequency electrical stimulation (T₁₀₀) of relaxed vastus lateralis muscle (VL) were obtained. Contractile properties of the VL were measured with passive twitch and maximal voluntary knee extension test (MVC). Changes in M-waves and SEMG during MVC test were used to evaluate the differences in myoelectrical signals. T₁₀₀/T₂₀ ratio decreased by 10.9 ± 8.4 % (p < 0.01) after the SSC exercise and increased by 35.9 ± 17.5 % (p < 0.001) after the CON exercise. Significant SEMG changes were observed only after the CON exercise where peak to peak time of the M-waves increased by 9.2 ± 13.3 % (p < 0.06), SEMG amplitude during MVC increased by 32.9 ± 21.6 % (p < 0.001) and SEMG power spectrum median frequency decreased by 11.0 ± 10.5 % (p < 0.05). It is concluded that high frequency fatigue wasn''t reflected in SEMG, however the SEMG changes after the CON seemed to reflect metabolic changes due to acidosis.

Key points

• The SSC exercise induced high-frequency fatigue which was not reflected in any SEMG change.
• The CON exercise induced dominantly low-frequency fatigue where only SEMG during MVC changed
• Muscle fibre membrane excitability was not changed due to low- and high-frequency fatigue but mainly reflected metabolic changes.
• Changes in muscle compound action potential did not follow those changes seen after electrically elicited HF and LF fatigue.

Key words: M-wave, stretch-shortening cycle, electrical stimulation, median frequency.     

The Role of Active Muscle Mass on Exercise-Induced Cardiovascular Drift

The purpose of this study was to examine the role of active muscle mass on cardiovascular drift (CV_drift) during prolonged exercise. Twelve subjects with peak oxygen uptake (VO_2peak) of 3.52 ± 0.52 L·min^-1 (mean ± SD) cycled for 55 min with 80 revolutions per minute with either two legs (2-legged) or one leg (1-legged). Oxygen uptake was at 60% of VO_2peak throughout the 2-legged trial and at half of this value in 1- legged condition. Cardiac output (CO-CO₂ rebreathing), heart rate (HR) and quadriceps integrated electromyographic activity (iEMG) were higher (p < 0.01) during 2-legged than 1- legged exercise. Changes in stroke volume from 20 to 50 min of exercise were greater in 2-legged than in 1-legged (∆SV: -20.8 ± 0.8 vs. -13.3 ± 1.3 ml·beat^-1, p < 0.05). Similarly, changes in heart rate (∆HR) were +18.5 ± 0.8 and +10.7 ± 1.0 beats·min^-1, in 2-legged and 1-legged, respectively (p < 0.01). Calculated blood volume changes declined significantly in 2-legged exercise (∆BV: -4.25 ± 0.43%, p < 0.05). Sympathetic activation as indicated by the ratio of low and high frequency in spectral analysis of HR (LF HF^-1 ratio) was higher in 2-legged than in 1- legged trial (p < 0.05). At the end of exercise, CO had a tendency to decrease from 20^th min in 2-legged (changes in CO = -0.92 ± 0.3 L·min^-1, p = 0.07), whereas it was maintained in 1- legged cycling (∆CO = -0.15 ± 0.2 L·min^-1, p = 0.86). Multiple regression analysis showed that HR rise and blood volume decline were predictors of SV drop whereas heart rate increase was explained by rectal temperature and magnitude of muscle mass activation, as indicated by iEMG (p < 0.05) in 2-legged cycling. In conclusion, apart from the well-known factors of thermal status and blood volume decline, it seems that muscle mass involved plays also a role on the development of CV_drift.

Key points

• The magnitude of the participated muscle mass plays a critical role for the development of cardiovascular drift, when the oxygen consumption per leg is the same.
• Apart from thermal status and blood volume decline, central command plays a role on cardiovascular regulation during steady state exercise performed with large muscle mass.

Key words: Prolonged cycling, cardiovascular regulation     

β-Ecdysone Augments Peak Bone Mass in Mice of Both Sexes

Background

One of the strongest predictors for osteoporosis is peak bone mass. Interventions to augment peak bone mass have yet to be developed. β-Ecdysone (βEcd), a natural steroid-like compound produced by arthropods to initiate metamorphosis, is believed to have androgenic effects and so may be used to augment bone mass.

Questions/purposes

The purpose of this study was to use both male and female (1) gonadal-sufficient; and (2) -insufficient mice to investigate sex differences in terms of bone development and structure after βEcd administration.

Methods

Two-month-old male and female Swiss-Webster mice were randomized to receive either vehicle or βEcd (0.5 mg/kg) for 3 weeks. In a separate experiment to evaluate the effects of βEcd on sex hormone-deficient mice, gonadectomy was performed in male (orchiectomy [ORX]) and female mice (ovariectomy [OVX]). Sham-operated and the ORX/OVX mice were then treated for 3 weeks with βEcd. Primary endpoints for the study were trabecular bone structure and bone strength.

Results

In male mice, the trabecular bone volume was 0.18 ± 0.02 in the placebo-treated (PL) and 0.23 ± 0.02 in the βEcd-treated group (p < 0.05 versus PL); and 0.09 ± 0.01 in the ORX group (p < 0.05 versus PL) and 0.12 ± 0.01 in the ORX + βEcd group. Vertebral bone strength (maximum load) was 43 ± 2 in PL and 51 ± 1 in the βEcd-treated group (p < 0.05 versus PL); and 30 ± 4 in the ORX group (p < 0.05 versus PL) and 37 ± 3 in the ORX + βEcd group. In female mice, trabecular bone volume was 0.23 ± 0.02 in PL and 0.26 ± 0.02 in the βEcd-treated group (p < 0.05 versus PL); and 0.15 ± 0.01 in the OVX group (p < 0.05 versus PL) and 0.14 ± 0.01 in the OVX + βEcd group. Maximum load of the vertebrae was 45 ± 2 in PL and 48 ± 4 in the βEcd-treated group; and 39 ± 4 in the OVX group (p < 0.05 versus PL) and 44 ± 4 in the OVX + βEcd group.

Conclusions

These findings suggest the potential use of βEcd in the augmentation of bone mass in growing male and female mice. It may also partially prevent the detrimental effects of gonadectomy on trabecular bone.

Clinical Relevance

Our results support the potential use of βEcd or nature products that are rich in βEcd to augment peak bone mass. βEcd may differ from the other anabolic hormone treatments that may have severe side effects such as serious cardiac complications. However, its effects on humans remain to be determined.