Plasma beta-thromboglobulin as a measure of platelet activity: Effect of risk factors and findings in ischemic heart disease and after acute myocardial infarction

The plasma concentration of beta-thromboglobulin (BTG), a platelet-specific protein released during platelet aggregation, is considered a sensitive marker of in vivo platelet activity. The mean plasma level in 133 asymptomatic individuals was 32.3 ± 1.1 ng/ml, and there was no difference between those with no risk factors (32.2 ± 1.2 ng/ml, n = 56), those who smoked (31.8 ± 1.8 ng/ml, n = 45), those with hyperlipidemia (32.8 ± 1.7 ng/ml, n = 15), and those exposed to both of these risk factors (34.1 ± 2.7 ng/ml, n = 17). The mean plasma BTG level in 104 patients with symptomatic ischemic heart disease was significantly elevated (40.9 ± 1.4 ng/ml, p < 0.01), but there was considerable overlap with normal levels. Although no difference was found between patients with no risk factors (38.1 ± 4.0 ng/ml, n = 13) and those with only 1 risk factor (37.0 ± 1.8 ng/ml, n = 44), patients with 2 or more risk factors had a significantly elevated plasma BTG level (45.2 ± 2.2 ng/ml, n = 47, p < 0.01). It is concluded that risk factors themselves do not increase platelet activity, but that patients with vascular disease have activated platelets that may contribute to the progression of the disease. Plasma BTG was also measured serially for 10 days in 29 patients after hospitalization with acute ischemic cardiac pain. Although the median plasma level was elevated above normal there were no acute changes in plasma BTG after either acute infarction (n = 22) or acute ischemia (n = 7), except in 2 patients in whom pericardial friction rubs developed. Thus, measurement of systemic plasma BTG did not detect platelet involvement in acute coronary occlusion or acute ischemia.     

<Emphasis Type="Italic">Staphylococcus aureus</Emphasis> Evasion of Host Immunity in the Setting of Prosthetic Joint Infection: Biofilm and Beyond

Purpose of Review

The incidence of complications from prosthetic joint infection (PJI) is increasing, and treatment failure remains high. We review the current literature with a focus on Staphylococcus aureus pathogenesis and biofilm, as well as treatment challenges, and novel therapeutic strategies.

Recent Findings

S. aureus biofilm creates a favorable environment that increases antibiotic resistance, impairs host immunity, and increases tolerance to nutritional deprivation. Secreted proteins from bacterial cells within the biofilm and the quorum-sensing agr system contribute to immune evasion. Additional immunoevasive properties of S. aureus include the formation of staphylococcal abscess communities (SACs) and canalicular invasion. Novel approaches to target biofilm and increase resistance to implant colonization include novel antibiotic therapy, immunotherapy, and local implant treatments.

Summary

Challenges remain given the diverse mechanisms developed by S. aureus to alter the host immune responses. Further understanding of these processes should provide novel therapeutic mechanisms to enhance eradication after PJI.

     

Substantially enhanced rate capability of lithium storage in Na2Ti6O13 with self-doping and carbon-coating

Na₂Ti₆O₁₃ (NTO) has recently been reported for lithium ion storage and showed very promising results. In this work, we report substantially enhanced rate capability in NTO nanowires by Ti(iii) self-doping and carbon-coating. Ti(iii) doping and carbon coating were found to work in synergy to increase the electrochemical performances of the material. For 300 cycles at 1C (1C = 200 mA g⁻¹) the charge capacity of the electrode is 206 mA h g⁻¹, much higher than that (89 mA h g⁻¹) of the pristine NTO electrode. For 500 cycles at 5C the electrode can still deliver a charge capacity of 180.5 mA h g⁻¹ with a high coulombic efficiency of 99%. At 20C the capacity of the electrode is 2.6 times that of the pristine NTO. These results clearly demonstrate that the Ti(iii) self-doping and uniform carbon coating significantly enhanced the kinetic processes in the NTO nanowire crystal, making it possible for fast charge and discharge in Li-ion batteries.

Ti³⁺ self-doping and carbon-coating are efficient approaches to simultaneously improve the rate capability and cyclability of Na₂Ti₆O₁₃ nanowires for lithium storage.     

Treatment of Partial Thickness Rotator Cuff Tears in Overhead Athletes

Purpose of Review

To review the etiology, classification, presentation, evaluation, treatment strategy, and outcomes in overhead athletes with partial thickness rotator cuff tears.

Recent Findings

Despite advances in surgical repair techniques, return to play following surgical repair of partial rotator cuff tears remains modest at best.

Summary

Overhead athletes may be particularly prone to rotator cuff pathology due to the supraphysiological strains within the tendon during the throwing motion, as well as mechanical stress with contact between the undersurface of the rotator cuff and the glenoid. The true prevalence of partial tears may be underestimated given the high incidence of asymptomatic tears. Both dynamic ultrasound and enhanced contrast MRI have improved our understanding of this pathology. For most overhead athletes, nonoperative management is the most common course. Despite advances in imaging, diagnosis, and surgical techniques, our ability to return these patients to their elite level is modest at best when nonoperative management fails and surgical treatment is performed. If a surgical route is needed, debridement alone is the most frequent procedure given concerns of over constraint and poor return to play with surgical repair of the partial thickness rotator cuff tear.

     

Patient‐level Factors and the Quality of Care Delivered in Pediatric Emergency Departments

Objective

Quality of care delivered to adult patients in the emergency department (ED) is often associated with demographic and clinical factors such as a patient's race/ethnicity and insurance status. We sought to determine whether the quality of care delivered to children in the ED was associated with a variety of patient‐level factors.

Methods

This was a retrospective, observational cohort study. Pediatric patients (<18 years) who received care between January 2011 and December 2011 at one of 12 EDs participating in the Pediatric Emergency Care Applied Research Network (PECARN) were included. We analyzed demographic factors (including age, sex, and payment source) and clinical factors (including triage, chief complaint, and severity of illness). We measured quality of care using a previously validated implicit review instrument using chart review with a summary score that ranged from 5 to 35. We examined associations between demographic and clinical factors and quality of care using a hierarchical multivariable linear regression model with hospital site as a random effect.

Results

In the multivariable model, among the 620 ED encounters reviewed, we did not find any association between patient age, sex, race/ethnicity, and payment source and the quality of care delivered. However, we did find that some chief complaint categories were significantly associated with lower than average quality of care, including fever (–0.65 points in quality, 95% confidence interval [CI] = –1.24 to –0.06) and upper respiratory symptoms (–0.68 points in quality, 95% CI = –1.30 to –0.07).

Conclusion

We found that quality of ED care delivered to children among a cohort of 12 EDs participating in the PECARN was high and did not differ by patient age, sex, race/ethnicity, and payment source, but did vary by the presenting chief complaint.

     

The immediate effect of osteopathic cervical spine mobilization on median nerve mechanosensitivity: A triple-blind,randomized, placebo-controlled trial

Background

Neurodynamics is a clinical medium for testing the mechanical sensitivity of peripheral nerves which innervate the tissues of both the upper and lower limb. Currently, there is paucity in the literature of neurodynamic testing in osteopathic research, and where there is research, these are often methodologically flawed, without the appropriate comparators, blinding and reliability testing.

Children With Chronic Pain: Response Trajectories After Intensive Pain Rehabilitation Treatment

Intensive pain rehabilitation programs for children with chronic pain are effective for many patients. However, characteristics associated with treatment response have not been well documented. In this article we report trajectories of pain and functional impairment in patients with chronic pain up to 1 year after intensive pain rehabilitation and examine baseline factors associated with treatment response. Patients (n?=?253) with chronic pain and functional disability were assessed at 5 time points (admission, discharge, 1-month, 4-month, and 12-month follow-ups). Individual trajectories were empirically grouped using SAS PROC TRAJ. For functional disability, 2 groups emerged: treatment responders (88%) and nonresponders (12%). Using a binomial logistic regression model to predict disability trajectory group, no baseline variables were significant predictors for the disability trajectory group. For pain, 3 groups emerged: early treatment responders (35%), late treatment responders (38%), and nonresponders (27%). Using multinomial regression analyses to predict pain trajectory group, older age, higher pain scores, fewer social difficulties, higher anxiety levels, and lower readiness to change were characteristics that distinguished nonresponders from responders; no significant predictors distinguished the late responders from the early responders. These results provide key information on the baseline factors that influence intensive pain rehabilitation outcomes, including risk factors that predict treatment nonresponse. Our findings have implications for developing more targeted treatment interventions.