COMPARISON OF WEARABLES FOR SELF-MONITORING OF HEART RATE IN CORONARY REHABILITATION PATIENTS.

The leading cause of morbidity and mortality in the world is ischemic heart disease. Physical activity is a major approach in prevention and therapy of cardiac diseases. Self-heart-rate-monitoring in daily life is an important point for health awareness of cardiac patients. Aim of this study was validation of measurement accuracy of seven different devices against ECG-monitoring during cardiac rehabilitation training on a bicycle ergometer. Tested devices were: Garmin Forerunner 35 (Garmin), Mio Fuse (Mio), Fitbit Charge HR (FitbitHR), Fitbit Surge (FitbitS), Withings Pulse™ Ox (Withings), Apple Watch Series 1 (Apple) and Pearl Fitness-Tracker (FBT-50.HR PRO.V4). All devices were tested on 35 participants with six timed measurements during 20 minutes constant load bicycle ergometer workout for each. Simultaneousely, ECG measurements were recorded. Pearson´s correlations were assessed. Apple, Mio, and Garmin showed excellent accuracy with close correlation to ECG for self-monitoring of heart rate (HR) during cycling. FitbitHR, Pearl and FitbitS presented reasonable results. In contrast, Withings showed poor correlation to ECG with significant differences. We found significant differences between the tested devices. Since accuracy is of major importance for cardiac patients, only Apple, Mio and Garmin could be recommended. However, further research within distinct clinical and non-clinical settings is necessary and should take different types of physical activities into account.

Biomechanical properties of adjustable extracortical graft fixations in ACL reconstruction.

BACKGROUND: Reliable biomechanical data about the strength of different tibial extracortical graft fixation devices is sparse. This biomechanical study compares the properties of tibial graft fixation in ACL reconstruction with either the ACL Tight Rope™ or the Rigid Loop Adjustable™ device. The hypothesis was that both fixation devices would provide comparable results concerning gap formation during cyclic loading and ultimate failure load. METHODS: Sixteen sawbone tibiae (Sawbones™) underwent extracortical fixation of porcine flexor digitorum profundus grafts for ACL reconstruction. Either the ACL Tight Rope™ (Arthrex) or the Rigid Loop Adjustable™ (DePuy Mitek) fixation device were used, resulting in 2 groups with 8 specimens per group. Biomechanical analysis included pretensioning the constructs 10 times with 0.75 Hz, then cyclic loading of 1,000 position-controlled cycles and 1,000 force-controlled cycles applied with a servohydraulic testing machine. Elongation during cyclic loading was recorded. After this, ultimate failure load and failure mode analysis were performed. RESULTS: No statistically significant difference could be noted between the groups regarding gap formation during cyclic loading (4.6 ± 2.6 mm for the Rigid Loop Adjustable™ vs. 6.6 ± 1.5 mm for the ACL Tight Rope™ (p > 0.05)), and ultimate failure loads (980 ± 101.9 N for the Rigid Loop Adjustable™ vs. 861 ± 115 N ACL Tight Rope™ (p > 0.05)). CONCLUSION: ACL Tight Rope™ and the Rigid Loop Adjustable™ fixation devices yield comparable biomechanical results for tibial extracortical graft fixation in ACL reconstruction. These findings may be of relevance for the future surgical decision-making in ACL reconstruction. Randomized controlled clinical trials comparing both fixation devices are desirable for the future.

[Injury prevention in amateur football with FIFA 11+ : What is implemented on the football pitch?] / Verletzungsprävention im Amateurfußball mit FIFA 11+ : Was kommt auf dem Sportplatz an?

BACKGROUND: The warm-up and injury prevention program FIFA 11+ was developed to reduce injuries in recreational and amateur level football. Despite systematic education it is uncertain what amount of knowledge is passed down to the lower recreational level football players and what exercises are implemented in the daily routine. This study presents the summarized experiences of German coaches about the implementation of exercises on the football pitch. MATERIAL AND METHODS: In this study 142 coaches who participated in 1 (of 5) of the 2­day courses between 2013 and 2017 were sent a questionnaire. The questionnaire consisted of 24 questions, which were developed by the football union of Lower Saxony. Incomplete questionnaires were excluded from the study. RESULTS: A total of 121 questionnaires could be analyzed, which is a response rate of 85.2%. The mean time period between the 2­day training and answering the questionnaire was 29 months. Of the participating coaches 82.6% indicated that they use the program regularly (22% of the coaches use it twice a week or more frequently, 34% use it only once a week) and 6% of the coaches use additional programs to prevent injuries. A total of 86% of the participants believed in a reduction in the incidence of injuries induced by the FIFA 11+ concept, 89% of the participants rated the FIFA 11+ program as good ors very good, 91% rated the teaching concept as good or very good and 94% of the participants would recommend the 2­day advanced course to others. DISCUSSION: The prevention program as well as the advanced training concept were evaluated very positively. Most coaches use the program regularly. Nevertheless, many coaches use the FIFA 11+ exercises less than the recommended twice a week. Most coaches praised the good structure of the program, but also wished for the possibility of variations. CONCLUSION: The prevention program FIFA 11+ is seen by coaches in recreational and amateur football as an effective tool to prevent injury. Implementation on the football pitch is regular but not as frequent as the evidence-based recommendations in the training concept.

[Evidence-based therapy for tendinopathy of the knee joint : Which forms of therapy are scientifically proven?] / Evidenzbasierte Therapie bei Tendinopathien am Kniegelenk : Welche Therapieformen sind wissenschaftlich belegt?

Tendinopathy in the region of the knee joint is a common pathological disorder. People active in sports, in particular, have a high probability of suffering from tendinopathy. Despite its high clinical relevance, the level of evidence of therapy options for tendinopathy in the knee region differs greatly. This review gives an overview of current evidence levels for therapy options in tendinopathy of the quadriceps, patellar and pes anserinus insertion tendons as well as of the distal iliotibial tract tendon. The treatment with platelet-rich plasma showed a significantly better outcome when used correctly and treatment with shock waves, operative treatment and sclerotherapy have also shown positive effects. Treatment with corticosteroid injections and with oral non-steroidal anti-inflammatory drugs (NSAID) showed positive short-term effects (follow-up ±4 weeks). No reasonable data are available for the treatment of tendinopathy in the knee region by acupuncture, fascial therapy or cryotherapy. The use of kinesio taping showed no significant relief from complaints compared with standard conservative treatment. The use of multimodal therapy without evidence is, therefore, particularly common in elite athletes.

Physical capacity and quality of life in patients with multiple sclerosis.

BACKGROUND: Physical capacity (PC) and quality of life (QoL) are both reduced in multiple sclerosis (MS). OBJECTIVE: Aim of our study was to investigate limitations in PC and QoL in response to the severity of MS. METHODS: The study involved 60 patients (PG) (Expanded Disability Status Scale EDSS 0-3:38, EDSS 3.5-6:22) and 48 healthy controls (CG). Endurance capacity was assessed as peak oxygen uptake (VO2peak) and ventilatory anaerobic threshold (VAT). Maximum force was measured in isokinetic testing. QoL was assessed using the SF-36-questionnaire and HALEMS. RESULTS: Patients with MS showed reduced VO2peak and QoL in comparison with CG. Patients with an EDSS >3 showed reduced VO2peak, and maximum force, however at the VAT there was no significant difference independent of the EDSS. The MS-specific QoL HALEMS and subscales 1, 4, 6, 8 and the physical sum score of the SF-36-questionnaire were evaluated to be better in patients with an EDSS ≤3. CONCLUSIONS: There are limitations within PC in patients with MS in comparison with a healthy CG; within the PG there are notes on a similar aerobic capacity but worsened anaerobic capacity in patients with an EDSS >3. This should be taken into account in future treatment strategies for training therapy.

Eighteen-year follow-up after rotationplasty for a grade IIIC open fracture of the distal femur.

We report the 18-year follow-up of a patient who underwent rotationplasty for severe bone loss and infection after an grade IIIC open fracture of the distal femur. The patient is now 49 years old and fully satisfied with his life. During the follow-up period, he has never had significant physical or psychological problems directly concerning the rotationplasty. The analysis of quality of life using the SF36 questionnaire revealed even higher scores than the normal healthy population in seven out of eight sub-categories. Clinical examination revealed bland soft tissues without hyperkeratosis or other signs of maladaptation. Articular and cutaneous proprioception was intact all over the left leg. The active extension/flexion of the prosthetic knee was 0°-0°-100° and 10°-0°-70° of the ankle joint. Manual testing of motor strength revealed grade five of five for dorsiflexion and plantar flexion of the ankle. Gait patterns including climbing slopes and stairs were close to normal. Examination in sports physiology showed lower maximum power of hip and knee muscles compared to the healthy side, but better muscular endurance. These findings emphasize that rotationplasty can be a good alternative to arthrodesis or amputation in trauma patients providing high satisfaction and activity levels in the long-term follow-up.

Direct observation of membrane retrieval in chromaffin cells by capacitance measurements.

This study was focussed on the identification of the endocytic organelles in chromaffin cells which retrieve large, dense core vesicle (LDCV)-membrane components from the plasma membrane. For this purpose, 'on-cell' capacitance measurements and electron microscopy were employed. We found capacitance steps and capacitance flickers, corresponding to single exo- and endocytic events. The analysis revealed that the total membrane surface of completely fused LDCVs is recycled by large endocytic vesicles and smaller, most likely clathrin-coated vesicles, at approximately the same ratio. These results were confirmed by rapid-freeze immuno-electron microscopy, where an extracellular marker was rapidly internalized into endocytic vesicles that morphologically resembled LDCVs.

A membrane protein enriched in endoplasmic reticulum exit sites interacts with COPII.

Although all mammalian COPII components have now been cloned, little is known of their interactions with other regulatory proteins involved in exit from the endoplasmic reticulum (ER). We report here that a mammalian protein (Yip1A) that is about 31% identical to S. cerevisiae and which interacts with and modulates COPII-mediated ER-Golgi transport. Yip1A transcripts are ubiquitously expressed. Transcripts of a related mammalian homologue, Yip1B, are found specifically in the heart. Indirect immunofluorescence microscopy revealed that Yip1A is localized to vesicular structures that are concentrated at the perinuclear region. The structures marked by Yip1A co-localized with Sec31A and Sec13, components of the COPII coat protein complex. Immunoelectron microscopy also showed that Yip1A co-localizes with Sec13 at ER exit sites. Overexpression of the hydrophilic N terminus of Yip1A arrests ER-Golgi transport of the vesicular stomatitis G protein and causes fragmentation and dispersion of the Golgi apparatus. A glutathione S-transferase fusion protein with the hydrophilic N terminus of Yip1A (GST-Yip1A) is able to bind to and deplete vital components from rat liver cytosol that is essential for in vitro vesicular stomatitis G transport. Peptide sequence analysis of cytosolic proteins that are specifically bound to GST-Yip1A revealed, among other proteins, mammalian COPII components Sec23 and Sec24. A highly conserved domain at the N terminus of Yip1A is required for Sec23/Sec24 interaction. Our results suggest that Yip1A is involved in the regulation of ER-Golgi traffic at the level of ER exit sites.

The Dictyostelium Bcr/Abr-related protein DRG regulates both Rac- and Rab-dependent pathways.

Dictyostelium discoideum DdRacGap1 (DRG) contains both Rho-GEF and Rho-GAP domains, a feature it shares with mammalian Bcr and Abr. To elucidate the physiological role of this multifunctional protein, we characterized the enzymatic activity of recombinant DRG fragments in vitro, created DRG-null cells, and studied the function of the protein in vivo by analysing the phenotypic changes displayed by DRG-depleted cells and DRG-null cells complemented with DRG or DRG fragments. Our results show that DRG-GEF modulates F-actin dynamics and cAMP-induced F-actin formation via Rac1-dependent signalling pathways. DRG's RacE-GAP activity is required for proper cytokinesis to occur. Additionally, we provide evidence that the specificity of DRG is not limited to members of the Rho family of small GTPases. A recombinant DRG-GAP accelerates the GTP hydrolysis of RabD 30-fold in vitro and our complementation studies show that DRG-GAP activity is required for the RabD-dependent regulation of the contractile vacuole system in Dictyostelium.

Regulation of Golgi structure and function by ARF-like protein 1 (Arl1).

Arl1 is a member of the ARF-like protein (Arl) subfamily of small GTPases. Nothing is known about the function of Arl1 except for the fact that it is essential for normal development in Drosophila and that it is associated with the Golgi apparatus. In this study, we first demonstrate that Arl1 is enriched at the trans side of the Golgi, marked by AP-1. Association of Arl1 with the Golgi is saturable in intact cells and depends on N-terminal myristoylation. Over-expression of Arl1(T31N), which is expected to be restricted to the GDP-bound form and thus function as a dominant-negative mutant, causes the disappearance of the Golgi apparatus (marked by Golgi SNARE GS28), suggesting that Arl1 is necessary for maintaining normal Golgi structure. Overexpression of Arl1(Q71L), a mutant restricted primarily to the activated GTP-bound form, causes an expansion of the Golgi apparatus with massive and stable Golgi association of COPI and AP-1 coats. Interestingly, Golgi ARFs also become stably associated with the expanded Golgi. Transport of the envelope protein of vesicular stomatitis virus (VSV-G) along the secretory pathway is arrested at the expanded Golgi upon expression of Arl1(Q71L). The structure of stacked cisternae of the Golgi is disrupted in cells expressing Arl1(Q71L), resulting in the transformation of the Golgi into an extensive vesicule-tubule network. In addition, the GTP form of Arl1 interacts with arfaptin-2/POR1 but not GGA1, both of which interact with GTP-restricted ARF1, suggesting that Arl1 and ARF1 share some common effectors in regulating cellular events. On the basis of these observations, we propose that one of the mechanisms for the cell to regulate the structure and function of the Golgi apparatus is through the action of Arl1.

Treatment of cubitus varus with osteotomy and Ilizarov external fixation.

A cubitus varus deformity, secondary to a supracondylar fracture, was treated with a short oblique osteotomy and the Ilizarov external fixator. An excellent anatomic and functional outcome resulted. This method may prove to be of significant value in the treatment of this difficult deformity.

Mammalian homologues of yeast sec31p. An ubiquitously expressed form is localized to endoplasmic reticulum (ER) exit sites and is essential for ER-Golgi transport.

The yeast coat protein II (COPII) is responsible for vesicle budding from the endoplasmic reticulum (ER). Mammalian functional homologues for all yeast COPII components, except for Sec31p, have been reported. We have cloned a mammalian cDNA whose product (Sec31A) is about 26% identical to Saccharomyces cerevisiae Sec31p. Data base searches also revealed another partial sequence encoding a polypeptide (Sec31B) that is 40% identical to Sec31A. Northern analysis revealed that Sec31A transcripts are ubiquitously and abundantly expressed, while Sec31B transcripts are particularly enriched in the testis and thymus, but present in very low levels in other tissues. Sec31A is localized to vesicular structures that scatter throughout the cell but are concentrated at the perinuclear region. The structures marked by Sec31A contain Sec13, a component of COPII that is well characterized to mark the ER exit sites. Immunoelectron microscopy revealed that Sec31A colocalizes with Sec13 in structures with extensive vesicular-tubular profiles. Antibodies raised against a C-terminal portion of Sec31A co-precipitate Sec13 and inhibit ER-Golgi transport of temperature-arrested vesicular stomatitis G protein in a semi-intact cell assay. Cytosol immunodepleted of Sec31A failed to support vesicular stomatitis G protein transport, which can be rescued by a high molecular weight fraction of the cytosol containing both Sec31A and Sec13. We conclude that Sec31A represents a functional mammalian homologue of yeast Sec31p.

Prenylation-dependent association of protein-tyrosine phosphatases PRL-1, -2, and -3 with the plasma membrane and the early endosome.

PRL-1, -2, and -3 represent a novel class of protein-tyrosine phosphatase with a C-terminal prenylation motif. Although PRL-1 has been suggested to be associated with the nucleus, the presence of three highly homologous members and the existence of a prenylation motif call for a more detailed examination of their subcellular localization. In the present study, we first demonstrate that mouse PRL-1, -2, and -3 are indeed prenylated. Examination of N-terminal epitope-tagged PRL-1, -2, and -3 expressed in transiently transfected cells suggests that PRL-1, -2, and -3 are present on the plasma membrane and intracellular punctate structures. Stable Chinese hamster ovary cells expressing PRL-1 and -3 in an inducible manner were established. When cells were treated with brefeldin A, PRL-1 and -3 accumulated in a collapsed compact structure around the microtubule-organizing center. Furthermore, PRL-1 and -3 redistributed into swollen vacuole-like structures when cells were treated with wortmannin. These characteristics of PRL-1 and -3 are typical for endosomal proteins. Electron microscope immunogold labeling reveals that PRL-1 and -3 are indeed associated with the plasma membrane and the early endosomal compartment. Expression of PRL-3 is detected in the epithelial cells of the small intestine, where PRL-3 is present in punctate structures in the cytoplasm. When cells are treated with FTI-277, a selective farnesyltransferase inhibitor, PRL-1, -2, and -3 shifted into the nucleus. Furthermore, a mutant form of PRL-2 lacking the C-terminal prenylation signal is associated with the nucleus. These results establish that the primary association of PRL-1, -2, and -3 with the membrane of the cell surface and the early endosome is dependent on their prenylation and that nuclear localization of these proteins may be triggered by a regulatory event that inhibits their prenylation.

Preferential association of syntaxin 8 with the early endosome.

Members of the syntaxin family play a fundamental role in vesicle docking and fusion of diverse transport events. We have molecularly characterized syntaxin 8, a novel member of the syntaxin family. The nucleotide sequence of cloned rat cDNA predicts a polypeptide of 236 residues with a carboxyl-terminal 18-residue hydrophobic domain that may function as a membrane anchor. Characteristic of syntaxins, syntaxin 8 also contain regions that have the potential to form coiled-coil structures. Among the known syntaxins, syntaxin 8 is most homologous to syntaxin 6 which is predominantly associated with the trans-Golgi network (TGN). The syntaxin 8 transcript is detected in all rat tissues examined by northern blot. Antibodies against recombinant syntaxin 8 recognize a 27 kDa protein that is enriched in membrane fractions containing the Golgi apparatus and the endosomal/lysosomal compartments. Syntaxin 8 in membrane extract could be incorporated into a 20S protein complex in a way that is dependent on the soluble N-ethylmaleimide-sensitive factor (NSF) and soluble NSF attachment protein ((alpha)-SNAP), suggesting that syntaxin 8 is indeed a SNAP receptor (SNARE). Indirect immunofluorescence microscopy reveals that the majority of syntaxin 8 is localized to the early endosome marked by Rab5. This is corroborated by immunogold labeling experiments showing enrichment of syntaxin 8 in the early endosome and its co-labeling with Rab5.

Rhythmic opening and closing of vesicles during constitutive exo- and endocytosis in chromaffin cells.

Constitutive exo- and endocytic events are expected to increase and diminish the cell surface area in small spontaneous steps. Indeed, cell-attached patch-clamp measurements in resting chromaffin cells revealed spontaneous upward and downward steps in the electrical capacitance of the plasma membrane. The most frequent step size indicated cell surface changes of <0.04 microm(2), corresponding to vesicles of <110 nm diameter. Often downward steps followed upward steps within seconds, and vice versa, as if vesicles transiently opened and closed their lumen to the external space. Transient openings and closings sometimes alternated rhythmically for tens of seconds. The kinase inhibitor staurosporine dramatically increased the occurrence of such rhythmic episodes by making vesicle closure incomplete and by inhibiting fission. Staurosporine also promoted transient closures of large endocytic vesicles possibly representing remnants of secretory granules. We suggest that staurosporine blocks a late step in the endocytosis of both small and large vesicles, and that endocytosis involves a reaction cascade that can act as a chemical oscillator.

Ethane-freezing/methanol-fixation of cell monolayers: a procedure for improved preservation of structure and antigenicity for light and electron microscopies.

In order to dissect at the ultrastructural level the morphology of highly dynamic processes such as cell motility, membrane trafficking events, and organelle movements, it is necessary to fix/stop time-dependent events in the millisecond range. Ideally, immunoelectron microscopical labeling experiments require the availability of high-affinity antibodies and accessibility to all compartments of the cell. The biggest challenge is to define an optimum between significant preservation of the antigenicity in the fixed material without compromising the intactness of fine structures. Here, we present a procedure which offers an opportunity to unify preparation of cell monolayers for immunocytochemistry in fluorescence and electron microscopy. This novel strategy combines a rapid ethane-freezing technique with a low temperature methanol-fixation treatment (EFMF) and completely avoids chemical fixatives. It preserves the position and delicate shape of cells and organelles and leads to improved accessibility of the intracellular antigens and to high antigenicity preservation. We illustrate the establishment of this procedure using Dictyostelium discoideum, a powerful model organism to study molecular mechanisms of membrane trafficking and cytoskeleton.

Influence of 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) on the localization of cathepsin B and cathepsin L in human lung tumor cells.

Cathepsins B and L are catabolic lysosomal enzymes but are likely candidates for extracellular proteolysis in normal and malignant processes. The signal mediator 12(S)-HETE selectively triggers a shot-gun release of cathepsin B. We have therefore investigated the intracellular distribution of cathepsins in unstimulated and 12(S)-HETE-stimulated tumor cells. Cathepsins B and L have only limited colocalization, which is found in the regions of synthesis and sorting (endoplasmic reticulum, Golgi, trans Golgi network). Treatment by 12(S)-HETE scatters cathepsin B but not cathepsin L and proform of cathepsin B. Colocalization with both mannose 6-phosphate receptors is very limited for both cathepsins. But extensive colocalization of cathepsin B and the endosomal/lysosomal marker CD63 (LIMP-I) documents the main fraction of the enzyme in these compartments. The supposed non-lysosomal fraction of cathepsin B is very likely the secretable material which follows a regulated secretory pathway. Storage and regulated secretion in tumor cells support extracellular proteolysis as a means in invasion which may lead to metastasis. But the mechanisms by which cells might acquire and eventually apply this means is still unknown.