Physiological Demands of Simulated Off-Road Cycling Competition

The purpose of the study was to measure the demands of off-road cycling via portable spirometry, leg-power output (PO), heart rate (HR) and blood lactate (BLa) concentration. Twenty-four male competitive cyclists (age: 29±7.2 yrs, height: 1.79 ± 0.05 m, body mass: 70.0 ± 4.9 kg, VO_2peak: 64.9 ± 7.5 ml·kg^-1·min^-1) performed simulated mountain bike competitions (COMP) and laboratory tests (LabT). From LabT, we determined maximal workload and first and second ventilatory thresholds (VT1, VT2). A high-performance athlete (HPA) was used for comparison with three groups of subjects with different sport-specific performance levels. Load profiles of COMP were also investigated during uphill, flat and downhill cycling. During the COMP, athletes achieved a mean oxygen uptake (VO_2COMP) of 57.0 ± 6.8 ml·kg^-1·min^-1 vs. 71.1 ml·kg^-1·min^-1 for the HPA. The PO_COMP was 2.66±0.43 W·kg^-1 and 3.52 W·kg^-1 for the HPA. PO_COMP, VO_2COMP and HR_COMP were compared to corresponding variables at the VT2 of LabT. LabT variables correlated with racing time (RT_COMP) and PO_COMP (p < 0.01 to <0.001; r-0.59 to -0.80). The VO_2peak (LabT) accounted for 65% of variance of a single COMP test. VO_2COMP, PO_COMP and also endurance variables measured from LabTs were found as important determinants for cross-country performance. The high average VO_2COMP indicates that a high aerobic capacity is a prerequisite for successful COMP. Findings derived from respiratory gas measures during COMPs might be useful when designing mountain bike specific training.

Key points

• Cross- country cycling is characterized by high oxygen costs due to the high muscle mass simultaneously working to fulfill the demands of this kind of sports.
• Heart rate and blood lactate concentration measures are not sensitive enough to assess the energy requirements of COMP. Therefore, respiratory gas and power output measures are helpful to provide new information to physiological profile of cross- country cycling.
• An excellent cycling-specific capacity is a prerequisite for successful off-road cycling.
• Data determined from LabT might be utilized to describe semi-specific abilities of MB- athletes on a cycle ergometer, while data originating from COMP might be useful when designing a mountain bike specific training.

Key words: Off-road cycling, mountain biking, oxygen uptake, power output, lactate, heart rate     

Management der Organverletzungen bei Adoleszenten

Trauma und Berufskrankheit - Unfälle stellen zwischen dem 1. und 20. Lebensjahr die häufigste Todesursache dar, wobei in bis zu 5 % der Fälle das Abdomen beteiligt ist. Beim...     

All-inside meniscal repair surgery: factors affecting the outcome

BackgroundMeniscal injury is currently a well-recognized source of knee dysfunction. While it would be ideal to repair all meniscus tears, the failure rate is significantly high, although it may be reduced by careful selection of the patients. Our objective was to assess the outcome of meniscal repair surgery and the role of simultaneous reconstruction of the anterior cruciate ligament (ACL).Results136 Meniscal repairs were performed in 122 patients with a mean age of 26.8 years. Mean follow-up duration was 9 months. 63 % of the patients underwent medial and 37 % underwent lateral meniscal repair, with failure rates of 19 % for medial and 12 % for lateral menisci. Ligament injuries were found in 61 % of the patients (n = 83). Failure of meniscal repair occurred in 14.5 % (n = 12) of the patients who had early ACL reconstruction and in 27 % (n = 22) of the patients who had delayed ACL reconstruction (p = 0.0006). The failure rate was found to be 13 % in patients who were younger than 25 years (61 %) and 15 % in patients who were older than 25 years (39 %).ConclusionThe success rate of meniscal repair was found to be significantly better when ACL reconstruction was performed simultaneously with meniscal repair.

Level of evidence

Level IV.     

Total ankle replacement for posttraumatic arthritis: Similar outcome in postfracture and instability arthritis: a comparison of 90 ankles

Background and purpose

Most studies on total ankle replacement (TAR) have used a case mix of patients. We evaluated the outcome of TAR performed for end-stage arthritis either because of fracture or ligamentous injury.

Patients and methods

We prospectively followed 88 consecutive patients (50 postfracture ankles and 40 ankles with instability arthritis (2 bilateral)) who underwent TAR between 2001 and 2009. Mean follow-up for both groups was 5 years.

Results

Preoperative varus deformity of 10° or more was present in 23 ankles in the instability group. At 6 years, survival with revision or salvage fusion as an endpoint was 87% (95% CI: 74–99) in the postfracture group and 79% (95% CI: 63–94) in the instability group. Progressive periprosthetic osteolysis was seen in 23 ankles, and required salvage fusion in 6. The number of reoperations was similar in both groups. Clinical outcome, as assessed with 2 ankle scores and 2 questionnaires, showed good results and was similar at the latest follow-up.

Interpretation

The outcome was similar in the postfracture and instability groups and also similar to that reported in series including a case mix of patients. In contrast to earlier reports, preoperative frontal plane deformity in this series was not identified as a risk factor for failure.Most published articles on total ankle replacement (TAR) have presented results from mixed cohorts of patients suffering from end-stage ankle arthritis of several different etiologies, such as posttraumatic arthritis, primary arthritis, and rheumatoid arthritis (Buechel et al. 2003, Wood et al. 2008, Bonnin et al. 2011, Rippstein et al. 2011, Barg et al. 2013, Zaidi et al. 2013). To our knowledge, there have been no studies on TAR concentrating exclusively on patients withposttraumatic arthritis, but some studies have focused on TAR in combined cohorts of posttraumatic and primary osteoarthritis (Saltzman et al. 2010, Bai et al. 2010, Flavin et al. 2013).This is surprising, as posttraumatic arthritis is considered to be the most frequent cause of ankle arthritis (Saltzman et al. 2005).2 subgroups of posttraumatic arthritis should be distinguished: (1) postfracture arthritis, secondary to an intra- or juxta-articular fracture; and (2) ligamentous posttraumatic arthritis, secondary to a single severe ankle sprain or as a result of recurrent or chronic instability (Valderrabano et al. 2009). We refer to the latter as instability arthritis. Patients suffering from end-stage instability arthritis frequently present with a varus deformity of the ankle as a result of both lateral ligament laxity and asymmetric cartilage loss medially (Harrington 1979, Doets et al. 2008, Ryssman and Myerson 2011).We evaluated the medium-term outcome of TAR for end-stage posttraumatic ankle arthritis and compared it for postfracture arthritis and for instability arthritis. Our research questions were whether patients treated with TAR for instability arthritis—as they more frequently have a deformity and perhaps also residual instability after TAR—will have worse results with respect to (1) implant survival, (2) the number of reoperations, and (3) ankle-specific and general patient- and physician-based outcomes.     

The Arabidopsis repressor of light signaling, COP1, is regulated by nuclear exclusion: mutational analysis by bioluminescence resonance energy transfer

Bioluminescence resonance energy transfer (BRET) between Renilla luciferase and yellow fluorescent protein has been adapted to serve as a real-time reporter on protein-protein interactions in live plant cells by using the Arabidopsis Constitutive photomorphogenesis 1 (COP1) protein as a model system. COP1 is a repressor of light signal transduction that functions as part of a nuclear E3 ubiquitin ligase. COP1 possesses a leucine-rich nuclear-exclusion signal that resides in a domain implicated in COP1 dimerization. BRET was applied in conjunction with site-directed mutagenesis to explore the respective contributions of the nuclear-exclusion and dimerization motifs to the regulation of COP1 activity in vivo. One specific mutant protein, COP1(L105A), showed increased nuclear accumulation but retained the ability to dimerize, as monitored by BRET, whereas other mutations inhibited both nuclear exclusion and COP1 dimerization. Mutant rescue and overexpression experiments indicated that nuclear exclusion of COP1 protein is a rate-limiting step in light signal transduction.     

Value of Holter monitoring in predicting long-term efficacy and inefficacy of amiodarone used alone and in combination with class 1A antiarrhythmic agents in patients with ventricular tachycardia

The value of two reported and two new ambulatory electrocardiographic (Holter) criteria was studied in 80 patients taking amiodarone for refractory recurrent sustained ventricular tachycardia. In the 80 patients, the four Holter criteria were as follows: I-85% or greater reduction of ventricular premature complexes and abolition of couplets and nonsustained ventricular tachycardia in 74 patients who had 10 or more ventricular premature complexes/h, or any couplets or nonsustained ventricular tachycardia/24 hours at baseline; II-abolition of nonsustained ventricular tachycardia in 51 patients who had nonsustained ventricular tachycardia at baseline; III-85% or greater reduction of ventricular premature complexes and abolition of nonsustained ventricular tachycardia in 64 patients who had 30 or more ventricular premature complexes/h at baseline; and IV-85% or greater reduction of ventricular premature complexes and abolition of nonsustained ventricular tachycardia in 73 patients who had 10 or more ventricular premature complexes/h at baseline. Amiodarone was judged effective in, respectively, 51 of 74, 44 of 51, 51 of 64 and 61 of 73 patients by criterion I, II, III or IV. During the follow-up period (19 +/- 20 months), there were 19 instances of recurrence of ventricular arrhythmia or sudden death. Actuarial arrhythmia-free survival rate at 24 months was 84, 74, 86 and 85%, respectively, in patients with efficacy by criterion I, II, III or IV and 61, 43, 48 and 39%, respectively, in patients with inefficacy (p less than 0.015 for all). Many patients with efficacy by Holter criteria, however, had a recurrence of arrhythmia, suggesting insensitivity of these Holter criteria.(ABSTRACT TRUNCATED AT 250 WORDS)     

Klinischer Stellenwert von Monointoxikationen mit Ibuprofen, Diclofenac und Metamizol

Zusammenfassung Fragestellung Aufgrund der steigenden Anzahl suizidaler und parasuizidaler Intoxikationen mit Schmerzmitteln, soll die Häufigkeit und der klinische Stellenwert von Monointoxikationen der drei häufigsten Generika der Gruppe der nichtsteroidalen und steroidalen Antirheumatika/Analgetika (ohne Berücksichtigung der Acetylsalicylsäure), Diclofenac, Ibuprofen und Metamizol, untersucht werden und eruiert werden, ab welcher Dosierung eine intensivmedizinische Überwachung nötig erscheint. Patienten und Methodik Im Untersuchungszeitraum vom 1. Januar 1995 bis 31. Dezember 2001 wurden alle beim Giftinformationszentrum Mainz dokumentierten Monointoxikationen o. g. Generika mittels des Datenverarbeitungsprogramms ADAM-Dok/-Aus (basierend auf Microsoft^®Access^®) ausgewertet. Die Feststellung des Schweregrades erfolgte mittels des Poison Severity Scores. Zur speziellen Betrachtung gelangten nur die nichtsteroidalen Antirheumatika/Analgetika. Ergebnisse Im o. g. Zeitraum kam es zu 1281 Monointoxikationen mit NSAR und SAR, davon 40% Ibuprofen, 31% Diclofenac und 13% Metamizol. Bei Monointoxikationen mit Ibuprofen kam es erst ab einer Dosierung von 300 mg/kg KG zu schwerwiegenden, lebensbedrohlichen Vergiftungserscheinungen. Bei Diclofenac und Metamizol zeigten sich komplett unterschiedliche klinische Verläufe (Hypotonie, Herzrhythmusstörung und Niereninsuffizienz bei niedriger Dosierung, Symptomfreiheit bei hoher Dosierung). Zusammenfassung Bei Monointoxikationen mit Ibuprofen sollte erst ab einer Dosierung von 300 mg/ kg KG eine intensivmedizinische Überwachung angestrebt werden. Aufgrund komplett unterschiedlicher klinischer Verläufe (schwere Symptome bei niedriger Dosierung und keine Symptome bei hoher Dosierung) ist bezüglich der Festlegung einer kritischen Dosierung bei Monointoxikationen mit Diclofenac und Metamizol zur Zeit keine klare Aussage möglich. Hierzu sollten weitere Untersuchungen folgen. Bei jeder Art von Intoxikation empfehlen wir die Rücksprache mit einem Giftinformationszentrum, z. B. 06131/19240.     

EDI results of Japanese and German women and possible sociocultural explanations

The goal of this study was to compare data for women with bulimia nervosa and for a healthy control group both in Japan and Germany. These data were obtained using the Eating Disorder Inventory (EDI‐2). In Germany, EDI‐2 data and BMI values were collected from 102 nurses in training, 57 female medical students, and 29 patients with bulimia nervosa. In Japan, data were gathered from 243 female ‘short college’ students and 20 patients with bulimia nervosa. The Japanese non‐clinical control group showed significantly higher values on nearly all EDI scales than the German control group. They had a markedly higher drive for thinness, though their BMI values were lower. When the German and the Japanese bulimia nervosa patients were compared, the Japanese patients also showed higher values than their German counterparts on three EDI scales, but these differences were negligible. It is suggested that sociocultural factors in Japan, in particular a significant dependency on social norms, may contribute to the high EDI values. Copyright © 2005 John Wiley & Sons, Ltd and Eating Disorders Association.