Modulation of diabetic wound healing using carbon monoxide gas-entrapping materials.

Diabetic wound healing is uniquely challenging to manage due to chronic inflammation and heightened microbial growth from elevated interstitial glucose. Carbon monoxide (CO), widely acknowledged as a toxic gas, is also known to provide unique therapeutic immune modulating effects. To facilitate delivery of CO, we have designed hyaluronic acid-based CO-gas-entrapping materials (CO-GEMs) for topical and prolonged gas delivery to the wound bed. We demonstrate that CO-GEMs promote the healing response in murine diabetic wound models (full-thickness wounds and pressure ulcers) compared to N2-GEMs and untreated controls.

Relative contributions of the supraspinatus cord and strap tendons to shoulder abduction and translation.

BACKGROUND: The supraspinatus (SS) is formed by a larger anterior bipennate muscle with a cord-like tendon and a posterior unipennate muscle with a strap-like tendon. There is a tendinous connection between the 2 SS subunits. Yet, the relative mechanical contribution of the SS cord and SS strap musculotendinous units to load transmission and subsequent shoulder abduction force is unknown. We hypothesized that a simulated SS cord vs. an SS strap tear would generate less shoulder abduction force and, further, an intact SS cord would offset the expected abduction loss from an SS strap tear, but the inverse would not be true. MATERIALS AND METHODS: Twenty fresh-frozen cadaveric specimens were tested in a shoulder simulator with physiological load vectors applied to the upper and lower subscapularis, SS cord, SS strap, infraspinatus, and teres minor. The roles of the SS cord and SS strap muscles were delineated by varying their loads, while keeping constant loads on other muscles. The randomized testing trials included a native condition and 4 test cases that simulated tears by dropping the load and force transfer via the SS cord-to-SS strap connection by adding the load. Testing was completed at both 0° and 30° of abduction. During each test, shoulder abduction force, rotator cuff strains, and humeral translation were measured. RESULTS: Simulated isolated SS cord and SS strap tears led to a significantly lower shoulder abduction force (P < .001). A simulated cord tear at 0° and 30° reduced the abduction force by 53% and 38%, respectively. A simulated strap tear at 0° and 30° dropped the abduction force by 27% and 23%, respectively. The decline in the abduction force was larger for the SS cord tear vs. SS strap tear (P ≤ .001). An SS cord tear with full-load transfer to the strap was able to recover to native values at both 0° and 30° (P ≥ .288). Likewise, an SS strap tear with full-load transfer to the SS cord showed a similar recovery to native values at both 0° and 30° (P ≥ .155). During full-load transfer, the tendon strain followed the loading pattern. An SS cord tear or SS strap tear did not cause a change in humeral translation (P ≥ .303). DISCUSSION: The mechanical findings support the efficacy of nonoperative treatment of small (<10 mm) SS tears,11 because an intact SS strap tendon can effectively offset the abduction loss of a torn SS cord tear and vice versa.

The pathoanatomy of atraumatic partial distal biceps tears: a cadaveric study.

Background: Partial distal biceps tears can occur in the short and/or long heads, leading to forearm pain and weakness. Yet, the pathoanatomy of atraumatic and traumatic partial tears are not understood. The goals of this study are to determine the distal biceps partial tear frequency and tear pattern in a cohort of cadaveric specimens. Methods: Fifty three fresh frozen cadavers (average age 70.4 ± 13.8 years, range 32-94) underwent elbow endoscopy to screen for partial tears. The partial tendon tear pattern was classified into either attritional (atraumatic), detachment on the tendon's lateral side, or avulsion (traumatic) rupture of the tendon fibers from bone on both the lateral and medial sides. The specimens were dissected and laser scanned to make 3D models. The tear location, shape, and area were calculated using gross dissection and the 3D models. Results: Atraumatic partial distal biceps tears were identified in 40% of the specimens, 72% involved both the long and short heads, 14% long head, and 14% short head. In all tears, the tendon fibers were only detached from the lateral side. The greatest tear width occurred near the short and long head junction. Conclusion: Atraumatic partial distal biceps tears are common. The tear originates on the lateral side of the tendon at the short and long head junction. All the tear patterns are attritional and no specimen had surgical treatment. This finding supports the current treatment recommendation of an initial period of nonoperative care for symptomatic atraumatic partial distal biceps tears.

Low-Cost, High-Pressure-Synthesized Oxygen-Entrapping Materials to Improve Treatment of Solid Tumors.

Tumor hypoxia drives resistance to many cancer therapies, including radiotherapy and chemotherapy. Methods that increase tumor oxygen pressures, such as hyperbaric oxygen therapy and microbubble infusion, are utilized to improve the responses to current standard-of-care therapies. However, key obstacles remain, in particular delivery of oxygen at the appropriate dose and with optimal pharmacokinetics. Toward overcoming these hurdles, gas-entrapping materials (GeMs) that are capable of tunable oxygen release are formulated. It is shown that injection or implantation of these materials into tumors can mitigate tumor hypoxia by delivering oxygen locally and that these GeMs enhance responsiveness to radiation and chemotherapy in multiple tumor types. This paper also demonstrates, by comparing an oxygen (O2 )-GeM to a sham GeM, that the former generates an antitumorigenic and immunogenic tumor microenvironment in malignant peripheral nerve sheath tumors. Collectively the results indicate that the use of O2 -GeMs is promising as an adjunctive strategy for the treatment of solid tumors.

Fungating Malignancies: Management of a Distinct Wound Entity.

GENERAL PURPOSE: To provide information on the surgical management of fungating malignancies as a distinct wound entity. TARGET AUDIENCE: This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. LEARNING OBJECTIVES/OUTCOMES: After participating in this educational activity, the participant will:1. Identify characteristics of patients in a study examining the treatment of fungating malignancies.2. Select common symptoms experienced by patients with fungating malignancies.3. Explain issues related to the surgical treatment of fungating malignancies.4. Identify a reason why patients with fungating breast masses may avoid medical care.

To address the literature gap on malignant fungating wound treatment by reporting two institutions' experiences with this disease process and proposing practices to improve care. A multi-institutional retrospective review was conducted of 44 patients with 45 malignant fungating wounds over an 11-year period. Patient characteristics, treatment history, and outcomes were analyzed. Of the 44 patients who met the inclusion criteria, 31 (70.5%) were women and 13 (29.5%) were men. The average age at presentation was 63.0 (SD, 16.1) years. The most common malignancy was breast cancer, accounting for more than half of cases (54.5%). The average surface area of the tumors at presentation was 110.3 (SD, 215.0; range, 2.2­1,140) cm 2 , whereas the average surface area at time of discharge/death was 104.6 (SD, 310.7; range, 0­1,800) cm 2 . Neither surface area at presentation ( P = .504) nor surface area at time of final follow-up ( P = .472) were significantly associated with death during the study time frame. In the era of advancing technologies and medical innovation, the benefits of palliative surgery, which helps mitigate an open wound, should not be overlooked. Improving end-of-life care is beneficial to the patient and families alike. As surgeons, we strive for a tangible cure, but providing palliative resection to enable death with dignity might be the most humane service of all.

Differences in Friction Performance between New and Worn Shoes.

Occupational ApplicationsSlips and falls are among the most common reason for non-fatal work accidents. Preventing slips in the workplace can be achieved by ensuring sufficient friction between the shoe and floor. As shoes are worn down, there is a decrease in the coefficient of friction, which increases the risk of injury from a slip and fall for the wearer. We found that shoes worn in the workplace commonly had friction performance that is about 25% lower than their new condition and that this effect was largest for shoes with the highest initial friction performance. These results inform the magnitude of improvement in friction performance that can be achieved through footwear replacement programs.

TECHNICAL ABSTRACTBackground As slip-resistant shoes are naturally worn, the coefficient of friction (COF) decreases. Proper and timely shoe replacement is an important factor for preventing injuries related to slips. Knowledge of the change in COF for naturally worn shoes in the workplace, relative to the COF of their new counterparts, is needed for a better understanding in this area. Methods: Slip-resistant shoes worn in the workplace and their new counterparts were mechanically tested to assess their COF. Eighteen pairs of shoes (new and worn) were tested on a whole-shoe slip testing device that simulates under-shoe slipping conditions. The COF was calculated for each pair of shoes at a shoe-floor angle of 17 ± 1° relative to the ground surface, a speed of 0.5 m/s, and a mean normal force of 250 ± 10 N. Results: A mean decrease in COF of 0.055 (25%) was observed when comparing the naturally worn shoes with the new shoes. New shoes with an initial higher COF showed a larger loss in COF due to wear. Conclusions: Naturally worn, slip-resistant shoes have substantively reduced COF compared to their new counterparts. These findings demonstrate the potential for programs that monitor and replace slip-resistant shoes as a means to prevent slips.

Defining the width of the normal tibial plateau relative to the distal femur: Critical normative data for identifying pathologic widening in tibial plateau fractures.

Tibial plateau widening in the setting of fracture is an indication for surgical treatment, and restoring width is an important goal of surgery. In order to identify and correct pathological widening, the width of the normal tibial plateau must first be defined. The aim of this study was to establish normative data for the width of the tibial plateau relative to the distal femur to enable surgeons to identify and correct pathological widening in the setting of tibial plateau fracture. Fifty-one uninjured anteroposterior (AP) knee radiographs and 11 XR and CT scans of lateral tibial plateau fractures were retrospectively reviewed. The distances measured included maximal distal femoral width, femoral articular width, tibial articular width, and lateral plateau widening. On average, lateral plateau widening was +0.02 ± 2.03 mm, indicating that the most lateral aspect of the tibial plateau is collinear with the most lateral aspect of the lateral epicondyle of the femur. In the fracture population, average widening was 7.13 ± 3.59 mm on XR and 6.57 ± 3.34 mm on CT, with an absolute difference between XR and CT of 1.19 ± 0.66 mm. In conclusion, this study is the first to define the radiographic anatomy of the proximal tibia quantitatively. In the setting of tibial plateau fracture, residual widening of 2.1 mm could be within normal variation. However, the authors consider widening >2.1 mm pathological. These values can be used for assessing pathological widening of tibial plateau fractures. Clin. Anat. 31:688-692, 2018. © 2018 Wiley Periodicals, Inc.

Thyroid cancer risk in airline cockpit and cabin crew: a meta-analysis.

BACKGROUND: Airline crew are exposed to ionizing radiation as part of their occupation and have a documented increased risk of melanoma and cataracts. However, whether their occupation predisposes them to an increased risk of thyroid cancer is not established. The purpose of this systematic review and meta-analysis was to assess the risk of thyroid cancer in airline cockpit and cabin crew compared with the general population. METHODS: The MEDLINE database accessed via PubMed and Cochrane Database were searched. We included cohort studies reporting the standardized incidence ratio (SIR) or standardized mortality ratio (SMR) of thyroid cancers in any flight-based occupation. RESULTS: Of the 1777 citations retrieved in PubMed, eight studies with a total of 243,088 aircrew members and over 3,334,114 person-years of follow-up were included in this meta-analysis. No relevant studies were identified on Cochrane Database. The overall summary SIR of participants in any flight-based occupation was 1.11 (95% CI, 0.79-1.57; p = 0.613; 6 records). The summary SIR for cockpit crew was 1.21 (95% CI, 0.75-1.95; p = 0.383; 4 records) and the summary SIR for cabin crew was 1.00 (95% CI, 0.60-1.66; p = 0.646; 2 records). The overall summary standardized mortality ratio for airline crew was 1.19 (95% CI, 0.59-2.39; p = 0.773; 2 records). CONCLUSION: Airline crew were not found to have a significantly elevated risk of thyroid cancer incidence or mortality relative to the general population. Future research should capitalize on the growing occupational cohort dataset and employ innovative methods to quantify lifetime radiation exposure to further assess thyroid cancer risk in airline crew.