BACKGROUND:The emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has altered the management of pediatric musculoskeletal infections. Yet, institution-to-institution ...differences in MRSA virulence may exist, suggesting a need to carefully examine local epidemiological characteristics. The purpose of this study was to compare MRSA and methicillin-sensitive S. aureus (MSSA) musculoskeletal infections with respect to prevalence and complexity of clinical care over the past decade at a single children’s hospital.
METHODS:We retrospectively reviewed a series of patients presenting to The Children’s Hospital of Philadelphia with a diagnosis of osteomyelitis, septic arthritis, or both over a 10-year period. Inclusion criteria were S. aureus (SA) infections proven by positive culture of blood, bone, or joint aspirate. Exclusion criteria were non-SA infectious etiologies. Hospital-acquired infections were also not included to exclusively evaluate acute, community-acquired cases. Data related to hospital course, laboratory values, and number of surgical interventions were collected and compared between MRSA and MSSA cohorts.
RESULTS:In our series of pediatric patients, we identified 148 cases of acute, community-acquired musculoskeletal SA infections (MRSA, n=37 and MSSA, n=111). The prevalence of MRSA musculoskeletal infections increased from 11.8% in 2001 to 2002 to 34.8% in 2009 to 2010. Compared with MSSA, MRSA infections resulted in higher presenting C-reactive protein levels (10.4 vs. 7.8 mg/L, P=0.04), longer inpatient stays (10 vs. 5 d, P<0.01), multiple surgical procedures (n>1) (38% vs. 14%, P<0.01), increased sequelae (27% vs. 6%, P<0.01), and more frequent admissions to the intensive care unit (16% vs. 3%, P<0.01).
CONCLUSIONS:At our institution over the past decade, we found an approximate 3-fold rise in community-acquired pediatric MRSA musculoskeletal infections accompanied by an elevated risk for complications during inpatient management. Awareness of the epidemiological trends of MRSA within the local community may guide parental counseling and facilitate timely and accurate clinical diagnosis and treatment.
LEVEL OF EVIDENCE:Level II—prognostic retrospective study.
Two new macromolecular crystallography (MX) beamlines at the National Synchrotron Light Source II, FMX and AMX, opened for general user operation in February 2017 Schneider et al. (2013). J. Phys. ...Conf. Ser.425, 012003; Fuchs et al. (2014). J. Phys. Conf. Ser.493, 012021; Fuchs et al. (2016). AIP Conf. Proc. SRI2015, 1741, 030006. FMX, the micro‐focusing Frontier MX beamline in sector 17‐ID‐2 at NSLS‐II, covers a 5–30 keV photon energy range and delivers a flux of 4.0 × 1012 photons s−1 at 1 Å into a 1 µm × 1.5 µm to 10 µm × 10 µm (V × H) variable focus, expected to reach 5 × 1012 photons s−1 at final storage‐ring current. This flux density surpasses most MX beamlines by nearly two orders of magnitude. The high brightness and microbeam capability of FMX are focused on solving difficult crystallographic challenges. The beamline's flexible design supports a wide range of structure determination methods – serial crystallography on micrometre‐sized crystals, raster optimization of diffraction from inhomogeneous crystals, high‐resolution data collection from large‐unit‐cell crystals, room‐temperature data collection for crystals that are difficult to freeze and for studying conformational dynamics, and fully automated data collection for sample‐screening and ligand‐binding studies. FMX's high dose rate reduces data collection times for applications like serial crystallography to minutes rather than hours. With associated sample lifetimes as short as a few milliseconds, new rapid sample‐delivery methods have been implemented, such as an ultra‐high‐speed high‐precision piezo scanner goniometer Gao et al. (2018). J. Synchrotron Rad.25, 1362–1370, new microcrystal‐optimized micromesh well sample holders Guo et al. (2018). IUCrJ, 5, 238–246 and highly viscous media injectors Weierstall et al. (2014). Nat. Commun.5, 3309. The new beamline pushes the frontier of synchrotron crystallography and enables users to determine structures from difficult‐to‐crystallize targets like membrane proteins, using previously intractable crystals of a few micrometres in size, and to obtain quality structures from irregular larger crystals.
The new Frontier Microfocus Macromolecular Crystallography beamline FMX in sector 17‐ID‐2 of the National Synchrotron Lightsource II provides an ultra‐bright microfocus beam and a flexible experimental station for structure determination from the most challenging crystals.
The highly automated macromolecular crystallography beamline AMX/17‐ID‐1 is an undulator‐based high‐intensity (>5 × 1012 photons s−1), micro‐focus (7 µm × 5 µm), low‐divergence (1 mrad × 0.35 mrad) ...energy‐tunable (5–18 keV) beamline at the NSLS‐II, Brookhaven National Laboratory, Upton, NY, USA. It is one of the three life science beamlines constructed by the NIH under the ABBIX project and it shares sector 17‐ID with the FMX beamline, the frontier micro‐focus macromolecular crystallography beamline. AMX saw first light in March 2016 and started general user operation in February 2017. At AMX, emphasis has been placed on high throughput, high capacity, and automation to enable data collection from the most challenging projects using an intense micro‐focus beam. Here, the current state and capabilities of the beamline are reported, and the different macromolecular crystallography experiments that are routinely performed at AMX/17‐ID‐1 as well as some plans for the near future are presented.
AMX (17‐ID‐1) is the highly automated macromolecular crystallography beamline at the NSLS‐II. Photon delivery system, beamline instrumentation, high‐performance computing environment and suites of applications are described for beamline scientists and users. AMX's primary mission is to support routine structure determination from the most challenging projects.
Background:
The addition of unconstrained internal rotation to the physical examination could allow for detection of more subtle degrees of ankle instability. We hypothesized that a simulated ...anterolateral drawer test allowing unconstrained internal rotation of the ankle would provoke greater displacement of the lateral talus in the mortise versus the anterior drawer test.
Methods:
Ten cadaveric lower extremities were tested in a custom apparatus designed to reproduce the anterior drawer test and the anterolateral drawer test, in which the ankle was allowed to internally rotate about the intact deep deltoid ligament while being subluxed anteriorly. Specimens were tested intact and with anterior tibiofibular ligament sectioned. A differential variable reluctance transducer was used to measure lateral talar displacement with anterior forces of 25 and 50 N.
Results:
No significant differences in talar displacement or ankle rotation were noted in intact specimens between the groups. Among sectioned specimens, significantly more talar displacement (25 N 6.5 ± 1.7 mm vs 3.8 ± 2.4 mm and 50 N 8.7 ± 0.9 mm vs 4.5 ± 2.5 mm, P < .001) and ankle rotation (25 N 13.9 ± 8.0 degrees vs 0.0 ± 0.0 degrees and 50 N 23.7 ± 5.8 degrees vs 0.0 ± 0.0 degrees, P < .001) were found in the anterolateral drawer versus anterior drawer group.
Conclusion:
In an ankle instability model, the anterolateral drawer test provoked almost twice the lateral talus displacement found with the anterior drawer test.
Clinical Relevance:
Allowing internal rotation of the ankle while testing for ankle instability may allow the examiner to detect more subtle degrees of ankle instability.
A correction in the paper by Lazo et al. (2021). J. Synchrotron Rad.28, 1649–1661 is made.
A correction in the paper by Lazo et al. (2021). J. Synchrotron Rad.28, 1649–1661 is made.
This study examined the hypothesis that superficial femoral artery (SFA) subintimal angioplasty (SI-PTA) can maintain limb salvage with minimal complications in patients with symptomatic occlusive ...arterial disease.
From March 1, 2004, until April 28, 2006, 78 patients with rest pain (62.2%), gangrene (25.6%), or severe progressive claudication (12.2%) were treated consecutively with 82 SFA SI-PTAs (4 bilateral). The mean age was 59 ± 1.2 years, and 21 (27%) of the patients were female. All patients were treated in the operating room under local anesthesia by using fluoroscopic guidance, and the percentage SFA that was occluded was measured during the diagnostic portion of the procedure. Selective stent placement was performed after successful recanalization of the occluded arterial segments. Patients were treated with chronic aspirin and clopidogrel bisulfate for 3 months and followed up at 30 days and then every 3 months with physical examination and arterial duplex scan.
Of the 82 SFA SI-PTA attempts, 76 (92%) were initially successful, with an increase in the ankle-brachial index from 0.46 ± 0.02 to 0.88 ± 0.01 (P < .001). Five of the six patients with a failed SFA SI-PTA were female, two of the six had had previous bypass attempts, and one of the six had had a previous SFA SI-PTA attempt by another physician. Forty-nine (64%) of the 76 initially successful SFA SI-PTAs required placement of a stent, and 43 (56.5%) of the successful 76 SFA SI-PTAs required additional PTA of 1 or more arterial segments. The group treated with a successful SFA SI-PTA had 42.5% ± 3.5% SFA occlusion, compared with 82% ± 10% (P < .05) in the group with a failed attempt at SFA SI-PTA. Two of the six patients with initial SI-PTA failure underwent leg amputation within 30 days, three were treated with successful leg bypass surgery, and one was lost to follow-up. Of the 76 successful SFA SI-PTAs, 5 (6.5%) failed within 90 days, and the patients were treated successfully with leg bypass surgery. Of the 71 limbs with patent SI-PTAs at 90 days, 68 have remained patent with a mean follow-up 10.4 ± 0.7 months (range, 2-24 months). Three of the 71 SFA SI-PTAs failed between 4 and 7 months (mean, 5 ± 0.7 months): 1 patient was treated with successful bypass surgery, 1 patient is currently considering further intervention, and 1 patient was treated with amputation. Ten (14%) of the 71 successful SFA SI-PTAs required limited PTA for asymptomatic restenosis, as identified by the arterial duplex scan (7.4 ± 1.4 months; range, 2-16 months). There were no perioperative deaths, and three patients have died during follow-up with patent SFA SI-PTAs (9.3 ± 1.4 months).
These data suggest that SFA SI-PTA can be successfully used for limb salvage with minimal morbidity and mortality in a group of patients with severe lower extremity occlusive vascular disease.
External fixation (EF) of tibia fractures has been associated with nonunions and malunions at our large pediatric trauma center. This study was designed to determine the successes and shortcomings of ...EF, especially with respect to maintenance of alignment and time to union. We believe that this will contribute to the limited amount of literature examining the complications associated with this treatment modality in the pediatric population. Thirty-one consecutive high-energy tibia fractures treated with EF over 4.5 years were analyzed. There were 22 boys and 9 girls (4-17 years old; mean, 11.9 years). Mean length of follow-up was 15 months. Of the 31 fractures analyzed, 19 were open fractures (12 closed, 3 grade I, 9 grade II, and 7 grade III). Of 30 fractures, 3 required skin graft, whereas 7 required fasciotomy. Mean duration of EF was 3.2 months. Mean time to union was 4.8 months. For complication rates, 4 of 30 had delayed union, 2 of 30 had nonunion, 8 of 30 had minor malunion, 3 of 30 had major malunion, 3 of 30 had leg length discrepancy, 8 of 30 had pin track infection, 3 of 30 had wound infection, 2 of 30 had osteomyelitis, and 4 of 30 required surgery for nonunion. Time to union differed between those aged 11 years or younger and those aged 12 years or older (means of 3.2 and 6.0 months, respectively; P = 0.001). Union time also differed between those with closed or grade I open fractures and those with grade II or III open fractures (3.9 and 5.7 months, respectively; P = 0.035). Leg length discrepancy rate differed between children aged 11 years or younger and those aged 12 years or older (3/13 and 0/18, respectively; P = 0.05). Although EF has been touted as the standard treatment of high-energy pediatric tibia fractures, our close analysis revealed a high rate of problems such as long union times (especially ages ≥12), malunion, leg length discrepancy (especially ages ≤11), and pin track infection.
The loss of renal function continues to be a frequent complication of the iodinated contrast agents used to perform diagnostic angiography and endovascular procedures. This study examined the ...hypothesis that contrast-induced renal injury is partly due to a decrease in cortical and medullary microvascular blood flow after the downregulation of endogenous renal cortical and medullary nitric oxide (NO) synthesis.
Anesthetized male Sprague-Dawley rats (300 g) had microdialysis probes or laser Doppler fibers inserted into the renal cortex to a depth of 2 mm and into the renal medulla to a depth of 4 mm. Laser Doppler blood flow was continuously monitored, and the microdialysis probes were connected to a syringe pump and perfused in vivo at 3 μL/min with lactated Ringer’s solution. Dialysate fluid was collected at time zero (basal) and 60 minutes after infusion of either saline or Conray 400 (6 mL/kg). Both groups were treated with saline carrier, N
ω-nitro-L-arginine methyl ester hydrochloride (L-NAME, 30 mg/kg), L-arginine (400 mg/kg), or superoxide dismutase (10,000 U/kg), an oxygen-derived free radical scavenger. Dialysate was analyzed for total NO and eicosanoid synthesis. The renal cortex and medulla were analyzed for inducible NO synthase (iNOS), cyclooxygenase-2 (COX2), prostacyclin synthase, and prostaglandin E
2 (PGE
2) synthase content by Western blot analysis.
Conray caused a marked decrease in cortical and medullary blood flow with a concomitant decrease in endogenous cortical NO, PGE
2, and medullary NO synthesis. The addition of L-NAME to the Conray further decreased cortical and medullary blood flow and NO synthesis, which were restored toward control by L-arginine. Neither L-NAME nor L-arginine (added to the Conray) altered cortical or medullary eicosanoids release. Medullary PGE
2 synthesis decreased when superoxide dismutase was added to the Conray treatment, suggesting that oxygen-derived free radicals had a protective role in maintaining endogenous medullary PGE
2 synthesis after Conray treatment. Conray did not significantly alter iNOS, COX-2, prostacyclin synthase, or PGE
2 synthase content.
These findings suggest that the downregulation of renal cortical and medullary NO synthesis contributes to the contrast-induced loss of renal cortical and medullary microvascular blood flow. Preservation of normal levels of renal cortical and medullary NO synthesis may help prevent or lessen contrast-induced renal vasoconstriction and lessen contrast-induced renal injury found after diagnostic and therapeutic endovascular procedures.
This study suggests that clinically relevant cortical and medullary vasodilators (NO and vasodilator prostanoids) are required to maintain microvascular renal cortical and medullary blood flow. This study combines in vivo techniques of microdialysis and laser Doppler flow probes to show that endogenous NO synthesis is important in serving a protective role to prevent vasoconstriction at the local cortical and medullary levels after radiocontrast administration. Understanding the mechanisms of contrast-induced nephropathy will help develop treatment regimens to either minimize or eliminate this important complication of contrast agents.
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