Background:
Intra-articular fractures of the calcaneus are a common injury to the hindfoot following high-energy trauma to the lower extremity. Treatment of these fractures has evolved. Due to the ...concern of wound complications associated with extensile open treatment, smaller incision techniques, such as the sinus tarsi approach, are increasing in popularity. A number of fixation strategies are utilized with this approach, and it is unknown which most accurately restores radiographic alignment. The purpose of this study was to compare the postoperative radiographic outcomes of a plate and screw construct versus a cannulated screw construct when using the sinus tarsi approach for open reduction and internal fixation (ORIF) of calcaneus fractures.
Methods:
After institutional review board approval, records for all patients treated surgically at our institution for calcaneus fractures from 2012 to 2017 were reviewed. Inclusion criteria were intra-articular calcaneus fractures, patients aged 18 years or older, and use of the sinus tarsi approach. Exclusion criteria were open fractures and fractures with less than 6 weeks of postoperative weightbearing, which were excluded for radiographic outcomes. A total of 51 fractures underwent ORIF using cannulated screws alone (group 1), and 23 fractures underwent ORIF using a sinus tarsi plate (group 2). Sixty-one fractures (41 vs 20, respectively) met criteria for radiographic comparison. The primary outcomes of interest included pre- and postoperative Bohler and Gissane angles, wound complications, unplanned return to the operating room (OR), and cost comparison.
Results:
There was no statistically significant difference between preoperative Bohler angles for group 1 (14.4 degrees) versus group 2 (12.2 degrees) (P = .44), nor was there a significant difference between postoperative Bohler angles for group 1 (30.1 degrees) versus group 2 (27.1 degrees) (P = .14). Similarly, preoperative Gissane angles for group 1 (130.5 degrees) and group 2 (133.4 degrees) (P = .54) and postoperative Gissane angles for group 1 (118.2 degrees) and group 2 (119.8 degrees) (P = .44) showed no statistically significant difference. There were a total of 3 wound complications in group 1 versus 2 wound complications in group 2 (P = .66). There was no statistically significant difference in operative duration (P = .97) or the number of unplanned returns to the OR between the 2 groups (P = .68). Based on the implants used at this institution, and depending on the number of screws used, the estimated cost range of a plate construct was $1070 to $1235, while the estimated cost range of a cannulated screw construct was $717 to $1264.
Conclusion:
When comparing the cannulated screw and plate and screw fixation techniques, there was no difference in restoration of the Bohler and Gissane angles. Furthermore, the amount of angular correction achieved by initial reduction showed no statistically significant difference between groups, and the amount of reduction lost between initial and final postoperative radiographs showed no statistically significant difference between groups. With regard to the 2 techniques, there was no statistically significant difference in rates of postoperative complications and return to the OR. Our data suggest that fixation using cannulated screws alone versus sinus tarsi plate provides similar radiographic outcomes and risk of complications. The 2 techniques were also similar in terms of implant costs. Our results indicate that either technique effectively improved radiographic parameters.
Level of Evidence:
Level III, retrospective comparative study.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Although exercise improves individual risk factors for metabolic syndrome (MS), there is little research on the effect of exercise on MS as a whole. The objective of this study was to determine how ...much exercise is recommended to decrease the prevalence of MS. Of 334 subjects randomly assigned, 227 finished and 171 (80 women, 91 men) had complete data for all 5 Adult Treatment Panel III–defined MS risk factors and were included in this analysis. Subjects were randomly assigned to a 6-month control or 1 of 3 eight-month exercise training groups of (1) low amount/moderate intensity (equivalent to walking ∼19 km/week), (2) low amount/vigorous intensity (equivalent to jogging ∼19 km/week), or (3) high amount/vigorous intensity (equivalent to jogging ∼32 km/week). The low-amount/moderate-intensity exercise prescription improved MS relative to inactive controls (p <0.05). However, the same amount of exercise at vigorous intensity was not significantly better than inactive controls, suggesting that lower-intensity exercise may be more effective in improving MS. The high-amount/vigorous-intensity group improved MS relative to controls (p <0.0001), the low-amount/vigorous-intensity group (p = 0.001), and the moderate-intensity group (p = 0.07), suggesting an exercise-dose effect. In conclusion, a modest amount of moderate-intensity exercise in the absence of dietary changes significantly improved MS and thus supported the recommendation that adults get 30 minutes of moderate-intensity exercise every day. A higher amount of vigorous exercise had greater and more widespread benefits. Finally, there was an indication that moderate-intensity may be better than vigorous-intensity exercise for improving MS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
INTRODUCTION
Almost all individuals with Down syndrome (DS) will develop neuropathological features of Alzheimer's disease (AD). Understanding AD biomarker trajectories is necessary for DS‐specific ...clinical interventions and interpretation of drug‐related changes in the disease trajectory.
METHODS
A total of 177 adults with DS from the Alzheimer's Biomarker Consortium‐Down Syndrome (ABC‐DS) underwent positron emission tomography (PET) and MR imaging. Amyloid‐beta (Aβ) trajectories were modeled to provide individual‐level estimates of Aβ‐positive (A+) chronicity, which were compared against longitudinal tau change.
RESULTS
Elevated tau was observed in all NFT regions following A+ and longitudinal tau increased with respect to A+ chronicity. Tau increases in NFT regions I‐III was observed 0–2.5 years following A+. Nearly all A+ individuals had tau increases in the medial temporal lobe.
DISCUSSION
These findings highlight the rapid accumulation of amyloid and early onset of tau relative to amyloid in DS and provide a strategy for temporally characterizing AD neuropathology progression that is specific to the DS population and independent of chronological age.
Highlights
Longitudinal amyloid trajectories reveal rapid Aβ accumulation in Down syndrome
NFT stage tau was strongly associated with A+ chronicity
Early longitudinal tau increases were observed 2.5–5 years after reaching A+
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Key points
The spinal alpha motoneuron is the only cell in the human CNS whose discharge can be routinely recorded in humans.
We have reengineered motor unit collection and decomposition approaches, ...originally developed in humans, to measure the neural drive to muscle and estimate muscle force generation in the in vivo cat model.
Experimental, computational, and predictive approaches are used to demonstrate the validity of this approach across a wide range of modes to activate the motor pool.
The utility of this approach is shown through the ability to track individual motor units across trials, allowing for better predictions of muscle force than the electromyography signal, and providing insights in to the stereotypical discharge characteristics in response to synaptic activation of the motor pool.
This approach now allows for a direct link between the intracellular data of single motoneurons, the discharge properties of motoneuron populations, and muscle force generation in the same preparation.
The discharge of a spinal alpha motoneuron and the resulting contraction of its muscle fibres represents the functional quantum of the motor system. Recent advances in the recording and decomposition of the electromyographic signal allow for the identification of several tens of concurrently active motor units. These detailed population data provide the potential to achieve deep insights into the synaptic organization of motor commands. Yet most of our understanding of the synaptic input to motoneurons is derived from intracellular recordings in animal preparations. Thus, it is necessary to extend the new electrode and decomposition methods to recording of motor unit populations in these same preparations. To achieve this goal, we use high‐density electrode arrays and decomposition techniques, analogous to those developed for humans, to record and decompose the activity of tens of concurrently active motor units in a hindlimb muscle in the in vivo cat. Our results showed that the decomposition method in this animal preparation was highly accurate, with conventional two‐source validation providing rates of agreement equal to or superior to those found in humans. Multidimensional reconstruction of the motor unit action potential provides the ability to accurately track the same motor unit across multiple contractions. Additionally, correlational analyses demonstrate that the composite spike train provides better estimates of whole muscle force than conventional estimates obtained from the electromyographic signal. Lastly, stark differences are observed between the modes of activation, in particular tendon vibration produced quantal interspike intervals at integer multiples of the vibration period.
Key points
The spinal alpha motoneuron is the only cell in the human CNS whose discharge can be routinely recorded in humans.
We have reengineered motor unit collection and decomposition approaches, originally developed in humans, to measure the neural drive to muscle and estimate muscle force generation in the in vivo cat model.
Experimental, computational, and predictive approaches are used to demonstrate the validity of this approach across a wide range of modes to activate the motor pool.
The utility of this approach is shown through the ability to track individual motor units across trials, allowing for better predictions of muscle force than the electromyography signal, and providing insights in to the stereotypical discharge characteristics in response to synaptic activation of the motor pool.
This approach now allows for a direct link between the intracellular data of single motoneurons, the discharge properties of motoneuron populations, and muscle force generation in the same preparation.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
IF WE BELIEVE THAT LEADERS ARE BORN NOT MADE, why worry about leadership? We either have it or we don't. And if we don't have the necessary traits, then leadership is someone else's problem. We ...simply need to follow. I happen to have a different belief. I believe that leadership, in fact, is for everyone, and that it is critically important.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
I OFTEN HEAR TEACHERS say that they use teamwork in their classes because it is needed by business. This may be true, but does simply working in teams actually improve team performance? Although ...educators excel at placing students in groups, I suspect they less often actually teach teamwork skills.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Motoneurons are unique in being the only neurons in the CNS whose firing patterns can be easily recorded in human subjects. This is because of the one-to-one relationship between the motoneuron and ...muscle cell behavior. It has long been appreciated that the connection of motoneurons to their muscle fibers allows their action potentials to be amplified and recorded, but only recently has it become possible to simultaneously record the firing pattern of many motoneurons via array electrodes placed on the skin. These firing patterns contain detailed information about the synaptic organization of motor commands to the motoneurons. This review focuses on parameters in these firing patterns that are directly linked to specific features of this organization. It is now well established that motor commands consist of three components, excitation, inhibition, and neuromodulation; the importance of the third component has become increasingly evident. Firing parameters linked to each of the three components are discussed, along with consideration of potential limitations in their utility for understanding the underlying organization of motor commands. Future work based on realistic computer simulations of motoneurons may allow quantitative "reverse engineering" of human motoneuron firing patterns to provide good estimates of the relative amplitudes and temporal patterns of all three components of motor commands.
Understanding how functional lipid domains in live cell membranes are generated has posed a challenge. Here, we show that transbilayer interactions are necessary for the generation of ...cholesterol-dependent nanoclusters of GPI-anchored proteins mediated by membrane-adjacent dynamic actin filaments. We find that long saturated acyl-chains are required for forming GPI-anchor nanoclusters. Simultaneously, at the inner leaflet, long acyl-chain-containing phosphatidylserine (PS) is necessary for transbilayer coupling. All-atom molecular dynamics simulations of asymmetric multicomponent-membrane bilayers in a mixed phase provide evidence that immobilization of long saturated acyl-chain lipids at either leaflet stabilizes cholesterol-dependent transbilayer interactions forming local domains with characteristics similar to a liquid-ordered (lo) phase. This is verified by experiments wherein immobilization of long acyl-chain lipids at one leaflet effects transbilayer interactions of corresponding lipids at the opposite leaflet. This suggests a general mechanism for the generation and stabilization of nanoscale cholesterol-dependent and actin-mediated lipid clusters in live cell membranes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We present MMT spectroscopic observations of H II regions in 42 low luminosity galaxies in the Spitzer Local Volume Legacy survey. For 31 of the 42 galaxies in our sample, we were able to measure the ...temperature sensitive OIII lambda4363 line at a strength of 4sigma or greater, and thus determine oxygen abundances using the "direct" method. Our results provide the first "direct" estimates of oxygen abundance for 19 of these galaxies. "Direct" oxygen abundances were compared to B-band luminosities, 4.5 mu m luminosities, and stellar masses in order to characterize the luminosity-metallicity and mass-metallicity relationships at low luminosity. Because of the low dispersions in these relationships, if an accurate distance is available, the luminosity of a low luminosity galaxy is often a better indicator of metallicity than that derived using certain "strong-line" methods, so significant departures from the L-Z relationships may indicate that caution is prudent in such cases.
To determine the influence of time from injury to surgery on neurological recovery and length of stay (LOS) in an observational cohort of individuals with traumatic spinal cord injury (tSCI), we ...analyzed the baseline and follow-up motor scores of participants in the Rick Hansen Spinal Cord Injury Registry to specifically assess the effect of an early (less than 24 h from injury) surgical procedure on motor recovery and on LOS. One thousand four hundred and ten patients who sustained acute tSCIs with baseline American Spinal Injury Association Impairment Scale (AIS) grades A, B, C, or D and were treated surgically were analyzed to determine the effect of the timing of surgery (24, 48, or 72 h from injury) on motor recovery and LOS. Depending on the distribution of data, we used different types of generalized linear models, including multiple linear regression, gamma regression, and negative binomial regression. Persons with incomplete AIS B, C, and D injuries from C2 to L2 demonstrated motor recovery improvement of an additional 6.3 motor points (SE=2.8 p<0.03) when they underwent surgical treatment within 24 h from the time of injury, compared with those who had surgery later than 24 h post-injury. This beneficial effect of early surgery on motor recovery was not seen in the patients with AIS A complete SCI. AIS A and B patients who received early surgery experienced shorter hospital LOS. While the issues of when to perform surgery and what specific operation to perform remain controversial, this work provides evidence that for an incomplete acute tSCI in the cervical, thoracic, or thoracolumbar spine, surgery performed within 24 h from injury improves motor neurological recovery. Early surgery also reduces LOS.
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