Evaluating clinical outcomes of two biceps tenodesis techniques: Loop 'N' Tack and subpectoral biceps tenodesis.

Purpose: Biceps tenodesis is an effective surgical procedure that can address pathologies of the long head of the biceps tendon. The purpose of this study was to evaluate clinical outcomes following two different biceps tenodesis techniques: Loop 'N' Tack biceps tenodesis and subpectoral biceps tenodesis. Hypothesis: Patients undergoing both the subpectoral biceps tenodesis and Loop 'N' Tack biceps tenodesis will have improvements in patient-reported outcomes. Methods: Hundred and sixty five consecutive patients who underwent biceps tenodesis were retrospectively identified and contacted by phone to collect visual analog scale pain scores, University of California, Los Angeles shoulder scores, Simple Shoulder Test scores, Single Assessment Numeric Evaluation scores, and American Shoulder and Elbow Surgeons scores. Range of motion, elbow flexion strength, and incidence of bicipital groove pain and Popeye deformity were recorded. Results: One Hundred and forty five patients were included in the study (55 subpectoral, 90 Loop 'N' Tack). Patients in both groups reported high American Shoulder and Elbow Surgeons, Simple Shoulder Test, University of California, Los Angeles, Single Assessment Numeric Evaluation shoulder function scores, low visual analog scale pain scores, and had a minimal risk of complications when measured one year postoperatively. Conclusion: Loop 'N' Tack biceps tenodesis and subpectoral biceps tenodesis techniques are reliable and effective procedures that can reduce pain scores and restore shoulder function when patients require surgical intervention.

A Proteomic Approach Identifies Isoform-Specific and Nucleotide-Dependent RAS Interactions.

Active mutations in the RAS genes are found in ∼30% of human cancers. Although thought to have overlapping functions, RAS isoforms show preferential activation in human tumors, which prompted us to employ a comparative and quantitative proteomics approach to generate isoform-specific and nucleotide-dependent interactomes of the four RAS isoforms, KRAS4A, KRAS4B, HRAS, and NRAS. Many isoform-specific interacting proteins were identified, including HRAS-specific CARM1 and CHK1 and KRAS-specific PIP4K2C and IPO7. Comparing the interactomes of WT and constitutively active G12D mutant of RAS isoforms, we identified several potential previously unknown effector proteins of RAS, one of which was recently reported while this article was in preparation, RADIL. These interacting proteins play important roles as knockdown or pharmacological inhibition leads to potent inhibition of cancer cells. The HRAS-specific interacting protein CARM1 plays a role in HRAS-induced senescence, with CARM1 knockdown or inhibition selectively increasing senescence in HRAS-transformed cells but not in KRAS4B-transformed cells. By revealing new isoform-specific and nucleotide-dependent RAS interactors, the study here provides insights to help understand the overlapping functions of the RAS isoforms.

Heterolytic Scission of Hydrogen Within a Crystalline Frustrated Lewis Pair.

We report the heterolysis of molecular hydrogen under ambient conditions by the crystalline frustrated Lewis pair (FLP) 1-{2-[bis(pentafluorophenyl)boryl]phenyl}-2,2,6,6-tetramethylpiperidine (KCAT). The gas-solid reaction provides an approach to prepare the solvent-free, polycrystalline ion pair KCATH2 through a single crystal to single crystal transformation. The crystal lattice of KCATH2 increases in size relative to the parent KCAT by approximately 2%. Microscopy was used to follow the transformation of the highly colored red/orange KCAT to the colorless KCATH2 over a period of 2 h at 300 K under a flow of H2 gas. There is no evidence of crystal decrepitation during hydrogen uptake. Inelastic neutron scattering employed over a temperature range from 4-200 K did not provide evidence for the formation of polarized H2 in a precursor complex within the crystal at low temperatures and high pressures. However, at 300 K, the INS spectrum of KCAT transformed to the INS spectrum of KCATH2. Calculations suggest that the driving force is more favorable in the solid state compared to the solution or gas phase, but the addition of H2 into the KCAT crystal is unfavorable. Ab Initio methods were used to calculate the INS spectra of KCAT, KCATH2, and a possible precursor complex of H2 in the pocket between the B and N of crystalline KCAT. Ex-situ NMR showed that the transformation from KCAT to KCATH2 is quantitative and our results suggest that the hydrogen heterolysis process occurs via H2 diffusion into the FLP crystal with a rate-limiting movement of H2 from inactive positions to reactive sites.

Activity-Guided Design of HDAC11-Specific Inhibitors.

Mammalian histone deacetylases (HDACs) are a class of enzymes that play important roles in biological pathways. Existing HDAC inhibitors target multiple HDACs without much selectivity. Inhibitors that target one particular HDAC will be useful for investigating the biological functions of HDACs and for developing better therapeutics. Here, we report the development of HDAC11-specific inhibitors using an activity-guided rational design approach. The enzymatic activity and biological function of HDAC11 have been little known, but recent reports suggest that it has efficient defatty-acylation activity and that inhibiting it could be useful for treating a variety of human diseases, including viral infection, multiple sclerosis, and metabolic diseases. Our best inhibitor, SIS17, is active in cells and inhibited the demyristoylation of a known HDAC11 substrate, serine hydroxymethyl transferase 2, without inhibiting other HDACs. The activity-guided design may also be useful for the development of isoform-specific inhibitors for other classes of enzymes.

Liposomal bupivacaine reduces opiate consumption after rotator cuff repair in a randomized controlled trial.

BACKGROUND: Arthroscopic rotator cuff repair (ARCR) provides excellent clinical outcomes but is often associated with significant postoperative pain. The use of intraoperative anesthesia in conjunction with multimodal pharmacologic strategies is a widely accepted approach for managing surgical pain and reducing opiate use. The purpose of this study was to determine whether using a combined field and suprascapular nerve block with liposomal bupivacaine (LB) in addition to an interscalene block would provide greater pain relief and a reduction in opiate consumption compared with an interscalene block alone. METHODS: The study enrolled 50 patients with full-thickness rotator cuff tears undergoing primary ARCR surgery. Patients were randomized to receive intraoperative LB (n = 25) or not (n = 25) and given postoperative "pain journals" to document visual analog scale pain scores and to track their daily opioid consumption during the first 5 postoperative days. RESULTS: Patients in the LB group reported statistically and clinically lower pain scores during postoperative days 1 and 2 (P < .0001 and P = .03, respectively). In addition, patients in the LB group consumed significantly fewer narcotics than the control group during the 5-day period, demonstrating a 64% reduction in total narcotic consumption (P = .002). CONCLUSION: The findings of this study suggest that the addition of LB to multimodal anesthetic protocols significantly reduces the acute perioperative pain experienced following rotator cuff repair and the number of narcotic pills consumed in the first 5 days after ARCR. Furthermore, the findings provide guidelines for postoperative narcotic prescribing to reduce the quantity of opiates prescribed.

Trapping of 18F-Fluciclovine (FACBC) in Superior Sagittal Sinus.

As F-fluciclovine (FACBC) becomes more popular, new incidental findings are discovered. We present here a case of a 71-year-old man with prostate cancer in whom an FACBC PET/CT showed uptake in the superior sagittal sinus, which was found to be simply due to a dilated superior sagittal sinus on subsequent MRI. Accumulation in the superior sagittal sinus is a variant that interpreters of FACBC PET/CT should be aware of.

Opiate Pain Medication Consumption in Cigarette Smokers following Total Hip Arthroplasty.

Purpose The purpose of the present study was to assess perception of pain and pain management in smokers versus nonsmokers who received a total hip arthroplasty (THA). Methods Patients who underwent THA from 2010 to 2016 were propensity score matched 1:1 based on race, body mass index, age, and sex. This yielded 124 smokers and 124 nonsmokers. Pain intensity was quantified using area under the curve for visual analog scale pain scores. Opioid consumption was determined using a morphine milliequivalent (mEq) conversion algorithm. An independent samples t -test and Chi-square analysis was conducted to assess continuous and categorical variables respectively. Results Smokers experienced a nonsignificantly increased pain intensity (198.1 vs. 185.7; p = 0.063). Smokers demonstrated significantly higher opioid consumption in both immediate postoperative (65.9 vs. 59.3 mEq; p = 0.045) and 90 days postoperative periods (619.9 vs. 458.9 mEq; p = 0.029). Conclusion Our study demonstrated a nonsignificantly increased pain intensity, and (in both the immediate and 90 days postoperative periods) a significantly higher opioid consumption following THA in patients who smoke cigarettes. This may be due to a relatively small effect size, warranting the need for larger prospective studies. Nevertheless, arthroplasty surgeons should encourage preoperative smoking cessation and alternative nonopioid analgesics to smoking patients receiving THA. Level of Evidence This is a level III, retrospective cohort study.

Multivalent Binding and Biomimetic Cell Rolling Improves the Sensitivity and Specificity of Circulating Tumor Cell Capture.

Purpose: We aimed to examine the effects of multivalent binding and biomimetic cell rolling on the sensitivity and specificity of circulating tumor cell (CTC) capture. We also investigated the clinical significance of CTCs and their kinetic profiles in patients with cancer undergoing radiotherapy treatment.Experimental Design: Patients with histologically confirmed primary carcinoma undergoing radiotherapy, with or without chemotherapy, were eligible for enrollment. Peripheral blood was collected prospectively at up to five time points, including before radiotherapy, at the first week, mid-point and final week of treatment, as well as 4 to 12 weeks after completion of radiotherapy. CTC capture was accomplished using a nanotechnology-based assay (CapioCyte) functionalized with aEpCAM, aHER-2, and aEGFR.Results: CapioCyte was able to detect CTCs in all 24 cancer patients enrolled. Multivalent binding via poly(amidoamine) dendrimers further improved capture sensitivity. We also showed that cell rolling effect can improve CTC capture specificity (% of captured cells that are CK+/CD45-/DAPI+) up to 38%. Among the 18 patients with sequential CTC measurements, the median CTC decreased from 113 CTCs/mL before radiotherapy to 32 CTCs/mL at completion of radiotherapy (P = 0.001). CTCs declined throughout radiotherapy in patients with complete clinical and/or radiographic response, in contrast with an elevation in CTCs at mid or post-radiotherapy in the two patients with known pathologic residual disease.Conclusions: Our study demonstrated that multivalent binding and cell rolling can improve the sensitivity and specificity of CTC capture compared with multivalent binding alone, allowing reliable monitoring of CTC changes during and after treatment. Clin Cancer Res; 24(11); 2539-47. ©2018 AACR.

Comparative Nucleotide-Dependent Interactome Analysis Reveals Shared and Differential Properties of KRas4a and KRas4b.

The KRAS gene encodes two isoforms, KRas4a and KRas4b. Differences in the signaling functions of the two KRas proteins are poorly understood. Here we report the comparative and nucleotide-dependent interactomes of KRas4a and KRas4b. Many previously unknown interacting proteins were identified, with some interacting with both isoforms while others prefer only one. For example, v-ATPase a2 and eIF2Bδ interact with only KRas4b. Consistent with the v-ATPase interaction, KRas4b has a significant lysosomal localization. Comparing WT and constitutively active G12D mutant KRas, we examined differences in the effector proteins of the KRas4a and KRas4b. Interestingly, KRas4a binds RAF1 stronger than KRas4b. Correspondingly, KRas4a can better promote ERK phosphorylation and anchorage-independent growth than KRas4b. The interactome data represent a useful resource to understand the differences between KRas4a and KRas4b and to discover new function or regulation for them. A similar proteomic approach would be useful for studying numerous other small GTPases.

Macroscopic Rotator Cuff Tendinopathy and Histopathology Do Not Predict Repair Outcomes of Rotator Cuff Tears.

BACKGROUND: Numerous studies have identified factors that may affect the chances of rotator cuff healing after surgery. Intraoperative tendon quality may be used to predict healing and to determine type of repair and/or consideration of augmentation. There are no data that correlate how gross tendon morphology and degree of tendinopathy affect patient outcome or postoperative tendon healing. Purpose/Hypothesis: The purposes of this study were to (1) compare the gross appearance of the tendon edge during arthroscopic rotator cuff repair with its histological degree of tendinopathy and (2) determine if gross appearance correlated with postoperative repair integrity. The hypothesis was that gross (macroscopic) tendon with normal thickness, no delamination, and elastic tissue before repair would have a correlation with low Bonar scores, higher postoperative American Shoulder and Elbow Surgeons (ASES) scores, and increased rates of postoperative tendon healing on ultrasound. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 105 patients undergoing repair of medium-size (1-3 cm) full-thickness rotator cuff tears were enrolled in the study. Intraoperatively, the supraspinatus tendon was rated on thickness, fraying, and stiffness. Tendon tissue was recovered for histological analysis based on the Bonar scoring system. Postoperative ASES and ultrasound assessment of healing were obtained 1 year after repair. Correlation between gross appearance of the tendon and rotator cuff histology was determined. RESULTS: Of the 105 patients, 85 were followed the study to completion. The mean age of the patients was 61.6 years; Bonar score, 7.5; preoperative ASES score, 49; and postoperative ASES score, 86. Ninety-one percent of repairs were intact on ultrasound. Gross appearance of torn rotator cuff tendon tissue did not correlate with histological appearance. Neither histological (Bonar) score nor gross appearance correlated with multivariate analysis of ASES score, postoperative repair status, or demographic data. CONCLUSION: The degree of tendinopathy did not correlate with morphological appearance of the tendon. Neither of these parameters correlated with healing or patient outcome. This study suggests that the degree of tendinopathy, unlike muscle atrophy, may not be predictive of outcomes and that, on appearance, poor quality tendon has adequate healing capacity. Therefore, abnormal gross tendon appearance should not affect the repair effort or technique.

Patient-reported quality of life during definitive and postprostatectomy image-guided radiation therapy for prostate cancer.

PURPOSE: The importance of patient-reported outcomes is well-recognized. Long-term patient-reported symptoms have been described for individuals who completed radiation therapy (RT) for prostate cancer. However, the trajectory of symptom development during the course of treatment has not been well-described in patients receiving modern, image-guided RT. METHODS AND MATERIALS: Quality-of-life data were prospectively collected for 111 prostate cancer patients undergoing RT using the validated Prostate Cancer Symptom Indices, which assessed 5 urinary obstructive/irritative and 6 bowel symptoms. Patients who received definitive RT (N = 73) and postprostatectomy RT (N = 38) were analyzed separately. The frequency and severity of symptoms over multiple time points are reported. RESULTS: An increasing number of patients had clinically meaningful urinary and bowel symptoms over the course of RT. A greater proportion of patients undergoing definitive RT reported clinically meaningful urinary symptoms at the end of RT compared with baseline in terms of flow (33% vs 19%) and frequency (39% vs 18%). Individuals receiving postprostatectomy radiation also reported an increase in symptoms including frequency (29% vs 3%) and nocturia (50% vs 21%). Clinically meaningful bowel symptoms were less commonly reported. Patients receiving definitive RT reported an increase in diarrhea (9% vs 4%) and urgency (12% vs 6%) at the completion of RT compared with baseline. Both bowel and urinary symptoms approached their baseline levels by the time of first follow-up after treatment completion. The majority of patients who had clinically meaningful urinary or bowel symptoms during RT did not have them at 2 years or beyond, and development of new symptoms in the long term was uncommon. CONCLUSIONS: There is a modest increase in urinary and bowel symptoms over the course of treatment for individuals receiving definitive and postprostatectomy image-guided RT. These data can help inform both providers and patients regarding the trajectory of symptoms and allow for reasonable expectations regarding toxicity under treatment.

HDAC8 Catalyzes the Hydrolysis of Long Chain Fatty Acyl Lysine.

The histone deacetylase (HDAC) family regulates many biological pathways through the deacetylation of lysine residues on histone and nonhistone proteins. Mammals have 18 HDACs that are classified into four classes. Class I, II, and IV are zinc-dependent, while class III is nicotinamide adenine dinucleotide (NAD+)-dependent lysine deacetylase or sirtuins. HDAC8, a class I HDAC family member, has been shown to have low deacetylation activity compared to other HDACs in vitro. Recent studies showed that several sirtuins, with low deacetylase activities, can actually hydrolyze other acyl lysine modifications more efficiently. Inspired by this, we tested the activity of HDAC8 using a variety of different acyl lysine peptides. Screening a panel of peptides with different acyl lysine modifications, we found that HDAC8 can catalyze the removal of acyl groups with 2-16 carbons from lysine 9 of the histone H3 peptide (H3K9). Interestingly, the catalytic efficiencies (kcat/Km) of HDAC8 on octanoyl, dodecanoyl, and myristoyl lysine are several-fold better than that on acetyl lysine. The increased catalytic efficiencies of HDAC8 on larger fatty acyl groups are due to the much lower Km values. T-cell leukemia Jurkat cells treated with a HDAC8 specific inhibitor, PCI-34051, exhibited an increase in global fatty acylation compared to control treatment. Thus, the de-fatty-acylation activity of HDAC8 is likely physiologically relevant. This is the first report of a zinc-dependent HDAC with de-fatty-acylation activity, and identification of HDAC8 de-fatty-acylation targets will help to further understand the function of HDAC8 and protein lysine fatty acylation.

Inverse approach to estimating larval dispersal reveals limited population connectivity along 700 km of wave-swept open coast.

Demographic connectivity is fundamental to the persistence and resilience of metapopulations, but our understanding of the link between reproduction and recruitment is notoriously poor in open-coast marine populations. We provide the first evidence of high local retention and limited connectivity among populations spanning 700 km along an open coast in an upwelling system. Using extensive field measurements of fecundity, population size and settlement in concert with a Bayesian inverse modelling approach, we estimated that, on average, Petrolisthes cinctipes larvae disperse only 6.9 km (±25.0 km s.d.) from natal populations, despite spending approximately six weeks in an open-coast system that was once assumed to be broadly dispersive. This estimate differed substantially from our prior dispersal estimate (153.9 km) based on currents and larval duration and behaviour, revealing the importance of employing demographic data in larval dispersal estimates. Based on this estimate, we predict that demographic connectivity occurs predominantly among neighbouring populations less than 30 km apart. Comprehensive studies of larval production, settlement and connectivity are needed to advance an understanding of the ecology and evolution of life in the sea as well as to conserve ecosystems. Our novel approach provides a tractable framework for addressing these questions for species occurring in discrete coastal populations.

Results of the 2013-2015 Association of Residents in Radiation Oncology Survey of Chief Residents in the United States.

PURPOSE: The purpose of this project was to survey radiation oncology chief residents to define their residency experience and readiness for independent practice. METHODS AND MATERIALS: During the academic years 2013 to 2014 and 2014 to 2015, the Association of Residents in Radiation Oncology (ARRO) conducted an electronic survey of post-graduate year-5 radiation oncology residents in the United States during the final 3 months of training. Descriptive statistics are reported. RESULTS: Sixty-six chief residents completed the survey in 2013 to 2014 (53% response rate), and 69 completed the survey in 2014 to 2015 (64% response rate). Forty to 85% percent of residents reported inadequate exposure to high-dose rate and low-dose rate brachytherapy. Nearly all residents in both years (>90%) reported adequate clinical experience for the following disease sites: breast, central nervous system, gastrointestinal, genitourinary, head and neck, and lung. However, as few as 56% reported adequate experience in lymphoma or pediatric malignancies. More than 90% of residents had participated in retrospective research projects, with 20% conducting resident-led prospective clinical trials and 50% conducting basic science or translational projects. Most chief residents reported working 60 or fewer hours per week in the clinical/hospital setting and performing fewer than 15 hours per week tasks that were considered to have little or no educational value. There was more than 80% compliance with Accreditation Council for Graduate Medical Education (ACGME) work hour limits. Fifty-five percent of graduating residents intended to join an established private practice group, compared to 25% who headed for academia. Residents perceive the job market to be more competitive than previous years. CONCLUSIONS: This first update of the ARRO chief resident survey since the 2007 to 2008 academic year documents US radiation oncology residents' experiences and conditions over a 2-year period. This analysis may serve as a valuable tool for those seeking to improve training of the next generation of oncology leaders.

Efficacy of topical benzoyl peroxide on the reduction of Propionibacterium acnes during shoulder surgery.

BACKGROUND: Propionibacterium acnes infection is a significant problem after shoulder surgery. Residual P. acnes is found on the skin up to 29% of the time immediately after surgical skin preparation and in 70% of dermal biopsy specimens. These residual bacteria may be a source for infection. Identifying more ideal skin preparation may help reduce the risk of infection. The purpose of this study was to evaluate the effect that topical benzoyl peroxide (BPO), with chlorhexidine skin preparation, would have on the presence of P. acnes cultured at the time of shoulder surgery. We hypothesized that adding topical BPO to our skin preparation would reduce the number of positive P. acnes cultures identified during surgery. METHODS: Fifty patients undergoing first-time shoulder surgery were treated with topical 5% BPO cream 48 hours before surgery. After skin preparation, 13 samples per subject were obtained. Cultures were held for 14 days. RESULTS: Fifty patients underwent arthroscopic shoulder surgery; 650 culture specimens were obtained. The skin was positive at the initiation of surgery in 6% of cases. Tissue samples were positive in 6%. The skin was positive in 10% at the end of surgery. None of these rates of positive culture were different from the 4% rate observed with a control swab. CONCLUSION: Application of BPO is an effective way to reduce P. acnes on skin at the beginning and, importantly, at the end of a surgical procedure. This may result in a lower risk for postoperative infection.

Application of human factors analysis and classification system model to event analysis in radiation oncology.

PURPOSE: To assess the applicability of the human factors analysis and classification system (HFACS) model for analyzing events in a radiation oncology environment by comparing the HFACS analysis results between novices and experts. METHODS AND MATERIALS: Four novices (resident physicians, 2-4 postgraduate years) volunteered to participate and were asked to independently perform the HFACS analysis on the selected 30 events. The events were divided into the following 2 sets: (1) the description of events was given in detail (eg, the conditions under which the events occurred including information about root causes of error); (2) the description of events was given without detailed information. Each novice's categorization of events into 4 main and 12 sublevels were compared with expert categorization ("gold standard") and used for statistical analysis. Analysis of variance was performed to test the difference in mean agreement with the expert-defined gold standard between the novices across the 4 main levels; and across the 12 sublevels independently. RESULTS: There were no significant differences in mean agreement with the expert-defined gold standard among the 4 novices (novice versus novice; P > .05) across the 4 main and 12 sublevels, respectively. There was a significant difference in mean agreement with the expert-defined gold standard among the 4 main levels and 12 sublevels (P < .05) across the 4 novices. For the 4 main levels, there was a significant difference in agreement with the expert-defined gold standard for events with detailed information versus events without detailed information provided across the 4 novices. The additional information did not improve mean agreement on the 12 sublevels. CONCLUSIONS: Novices learned to use the HFACS model for higher level analysis (4 main levels) with 1 hour training. Regardless of the amount of detail provided in the event description, the study results indicate a need of formal training for novices to better understand the definition and their interpretation at the 12 sublevel analyses.

Safety of open suprapectoral and subpectoral biceps tenodesis: an anatomic assessment of risk for neurologic injury.

BACKGROUND: Surgical techniques for proximal biceps tenodesis that include penetration of the posterior humeral cortex for fixation may pose risk to the surrounding neurovascular structures. HYPOTHESIS: The risk of neurologic injury with techniques that involve penetration of the posterior humeral cortex for fixation in proximal biceps tenodesis will increase as the tenodesis site moves proximally from the subpectoral to the suprapectoral location. METHODS: Proximal biceps tenodesis was performed on 10 cadaveric upper extremities with 3 separate techniques. The proximity of the hardware to the relevant neurovascular structures was measured. The distances between the tenodesis site and the relevant neurovascular structures were measured. RESULTS: The guide pin was in direct contact with the axillary nerve in 20% of the suprapectoral tenodeses. The distance between the axillary nerve and the tenodesis site was 10.5 ± 5.5 mm for the suprapectoral location, 36.7 ± 11.2 mm in the subpectoral scenario, and 24.1 ± 11.2 mm in the 30° cephalad scenario (P = .003). The distance between the radial nerve and the anterior tenodesis site was 41.3 ± 9.3 mm for the suprapectoral location and 48.0 ± 10.7 mm for the subpectoral location. The distance of the musculocutaneous nerve from the tenodesis site was 28.4 ± 9.2 mm for the suprapectoral location and 37.4 ± 11.2 mm for the subpectoral location. CONCLUSION: In a cadaveric model of open biceps tenodesis, penetration of the posterior humeral cortex at the suprapectoral location results in proximity to the axillary nerve and should be avoided. Subpectoral bicortical button fixation drilled perpendicular to the axis of the humerus was a uniformly safe location with respect to the axillary nerve.

Presence of Propionibacterium acnes in primary shoulder arthroscopy: results of aspiration and tissue cultures.

BACKGROUND: Infection after shoulder surgery has a serious impact on patient outcome and costs associated with care. Propionibacterium acnes infection may be insidious and manifest years after index surgery with resultant joint arthropathy or prosthesis infection. Our goal was to evaluate the presence of P. acnes in a group of patients undergoing primary arthroscopic shoulder surgery to better understand this organism. METHODS: Samples were collected from 57 patients undergoing first-time shoulder arthroscopy. Demographic data and medical comorbidities were collected. A control, 2 skin swabs, synovial fluid, and 3 tissue samples were obtained. All samples were placed on aerobic plates, on anaerobic plates, and in thioglycolate broth and held for 28 days. RESULTS: Fifty-seven patients underwent arthroscopic shoulder surgery. The mean age was 51 years. Eighty-one samples (21.8%) were positive for P. acnes when cultures were held 14 days; 32 subjects (56%) had at least 1 culture that grew P. acnes. Positive skin cultures for P. acnes increased from 15.8% before incision to 40.4% at closure. This was even more pronounced in men as positive skin cultures increased from 31.3% before incision to 63.0% at closure. Thirteen patients (22.8%) had more than 3 cultures positive. None of the patients in this study have had signs or symptoms to suggest clinical P. acnes infection. CONCLUSIONS: Of all subjects studied, 56% had at least 1 positive culture; 21% (of all 371 culture specimens obtained) grew P. acnes. We suspect that it is a consequence of true positive cultures from imperfect skin preparation and dermal contamination.

Pharmacologic attenuation of the hyperdynamic response to supraceliac aortic clamping.

BACKGROUND: Aortic occlusion is accompanied by a hyperdynamic cardiovascular response secondary to increased systemic vascular resistance and increased cardiac output. This study was designed primarily to determine the safety and cardiovascular response to hydrogen sulfide (H2S; HS) administration with supraceliac aortic cross-clamp and, secondarily, on short-duration resuscitation. METHODS: A validated porcine model (five sham swine compared with five controls) demonstrated a significant hyperdynamic cardiovascular response to 35% blood volume hemorrhage, 50-minute suprarenal aortic cross-clamping, and 6-hour resuscitation. Eight additional experimental swine were administered HS at 4 mg/min during aortic cross-clamping. RESULTS: During the cross-clamp period, hemodynamic curves of mean arterial pressure and heart rate demonstrated a blunting effect with HS administration, with a significant decrease being seen with mean arterial pressure at the end of the cross-clamp period (120 vs 149 mm Hg; P = .04). Resuscitation requirements were significantly reduced at 6 hours because the HS cohort received 8 L less crystalloid (P = .001) and 10.4 mg less epinephrine (P < .001). There was not a significant change in cardiac output, systemic vascular resistance, pulmonary vascular resistance, or pathologic liver analysis. CONCLUSIONS: The administration of HS during the 50 minutes of supraceliac aortic cross-clamp significantly reduced stress of the left heart. On clamp release, HS significantly reduced the need for volume and pressors. HS has positive benefits during cross-clamp and subsequent resuscitation, demonstrating that targeted pharmacologic therapy is possible to minimize adverse physiologic changes with aortic occlusion.

Effect of elevated pCO2 on metabolic responses of porcelain crab (Petrolisthes cinctipes) Larvae exposed to subsequent salinity stress.

Future climate change is predicted to alter the physical characteristics of oceans and estuaries, including pH, temperature, oxygen, and salinity. Investigating how species react to the influence of such multiple stressors is crucial for assessing how future environmental change will alter marine ecosystems. The timing of multiple stressors can also be important, since in some cases stressors arise simultaneously, while in others they occur in rapid succession. In this study, we investigated the effects of elevated pCO2 on oxygen consumption by larvae of the intertidal porcelain crab Petrolisthes cinctipes when exposed to subsequent salinity stress. Such an exposure mimics how larvae under future acidified conditions will likely experience sudden runoff events such as those that occur seasonally along portions of the west coast of the U.S. and in other temperate systems, or how larvae encounter hypersaline waters when crossing density gradients via directed swimming. We raised larvae in the laboratory under ambient and predicted future pCO2 levels (385 and 1000 µatm) for 10 days, and then moved them to seawater at ambient pCO2 but with decreased, ambient, or elevated salinity, to monitor their respiration. While larvae raised under elevated pCO2 or exposed to stressful salinity conditions alone did not exhibit higher respiration rates than larvae held in ambient conditions, larvae exposed to elevated pCO2 followed by stressful salinity conditions consumed more oxygen. These results show that even when multiple stressors act sequentially rather than simultaneously, they can retain their capacity to detrimentally affect organisms.