Augmentation of rotator cuff repair with gelatin-resorcin-formalin glue: a biomechanical study.

Introduction: Rotator cuff tendons are typically reattached to the proximal humerus using transosseous sutures or suture anchors. Their primary mode of failure is at the tendon-bone interface. Methods: We investigated the addition of an adhesive, gelatin-resorcin-formalin (GRF) glue, to a single-row rotator cuff repair (RCR) on ex vivo sheep models. We hypothesised the addition of GRF glue would increase the repair construct strength. The study consisted of three groups of six sheep infraspinatus tendons with an inverted-mattress stitch, tension-band configuration. Group 1 was the control group where no glue was applied. Group 2 involved applying 2 × 2 cm of GRF glue to the infraspinatus footprint and a 2-min curing time. Group 3 allowed for a 15-min cure time. Results: Failure occurred at the tendon-bone-suture interface in 6/6 of the control group, and 4/6 from groups 2 and 3. Failure occurred via the suture pulling out of the anchor in 2/6 of groups 2 and 3. No significant differences were noted between all three groups in ultimate failure load, repair stiffness or total energy to failure (p > 0.05). Discussion: The addition of GRF glue to the tendon-bone-suture interface did not enhance RCR strength in an ovine model.

Iron polypyridyl complex adsorbed on carbon surfaces for hydrogen generation.

A series of homogeneous Fe(iii) complexes were recently reported that are active for electrocatalytic hydrogen generation. Herein we report a naphthalene-terminated Fe(iii) complex for use in the functionalization of glassy carbon surfaces for electrocatalytic hydrogen generation with retention of catalytic activity.

Surgical Management of Proximal Tibiofibular Joint Instability Using an Adjustable Loop, Cortical Fixation Device.

A technique for proximal tibiofibular joint stabilization using an adjustable loop, cortical fixation device is presented. A standard diagnostic arthroscopy is performed to exclude intra-articular pathology. After arthroscopy, a 5-cm posterior-based curvilinear incision is made over the fibular head with dissection of the fascia and decompression of the common peroneal nerve ensuring adequate exposure of the fibular head. A guidewire is placed across 4 cortices using fluoroscopic guidance from the fibular head to the anteromedial tibia. A cannulated drill bit is guided through the 4 cortices. A shuttle wire carrying the adjustable loop, cortical fixation device is fed from lateral to medial and through the skin until the medial cortical button is deployed. The device is tightened until the lateral circular cortical button is secured on the fibula. Fluoroscopy is performed to confirm the button position. The device is secured after tensioning by tying the sutures. To confirm joint stabilization, a shuck test can be performed. If a second fixation device is necessary, this procedure can be repeated distally to the first.

Inflammatory Monocytes Promote Perineural Invasion via CCL2-Mediated Recruitment and Cathepsin B Expression.

Perineural invasion (PNI) is an ominous event strongly linked to poor clinical outcome. Cells residing within peripheral nerves collaborate with cancer cells to enable PNI, but the contributing conditions within the tumor microenvironment are not well understood. Here, we show that CCR2-expressing inflammatory monocytes (IM) are preferentially recruited to sites of PNI, where they differentiate into macrophages and potentiate nerve invasion through a cathepsin B-mediated process. A series of adoptive transfer experiments with genetically engineered donors and recipients demonstrated that IM recruitment to nerves was driven by CCL2 released from Schwann cells at the site of PNI, but not CCL7, an alternate ligand for CCR2. Interruption of either CCL2-CCR2 signaling or cathepsin B function significantly impaired PNI in vivo Correlative studies in human specimens demonstrated that cathepsin B-producing macrophages were enriched in invaded nerves, which was associated with increased local tumor recurrence. These findings deepen our understanding of PNI pathogenesis and illuminate how PNI is driven in part by corruption of a nerve repair program. Further, they support the exploration of inhibiting IM recruitment and function as a targeted therapy for PNI. Cancer Res; 77(22); 6400-14. ©2017 AACR.

Cobalt Schiff-base complexes for electrocatalytic hydrogen generation.

Two cobalt(iii) complexes containing inexpensive Schiff-base ligands have been found to be active for proton reduction at low overpotentials. The dinitro and tetranitro derivatized Schiff-base complexes show catalytic activity at -0.96 V and -1.1 V vs. Fc+/Fc, respectively, resulting in overpotentials of 120 mV and 280 mV. Foot-of-the-wave analysis is used to examine the kinetic properties of these complexes, yielding a theoretical TOFmax of up to 4100 s-1. Experimental TOFs of 7 s-1and 3 s-1 are observed. Catalytic Tafel plots are also presented in order to benchmark the relationship between turnover frequency and overpotential.

The Relationship Between Shoulder Stiffness and Rotator Cuff Healing: A Study of 1,533 Consecutive Arthroscopic Rotator Cuff Repairs.

BACKGROUND: Retear and stiffness are not uncommon outcomes of rotator cuff repair. The purpose of this study was to evaluate the relationship between rotator cuff repair healing and shoulder stiffness. METHODS: A total of 1,533 consecutive shoulders had an arthroscopic rotator cuff repair by a single surgeon. Patients assessed their shoulder stiffness using a Likert scale preoperatively and at 1, 6, 12, and 24 weeks (6 months) postoperatively, and examiners evaluated passive range of motion preoperatively and at 6, 12, and 24 weeks postoperatively. Repair integrity was determined by ultrasound evaluation at 6 months. RESULTS: After rotator cuff repair, there was an overall significant loss of patient-ranked and examiner-assessed shoulder motion at 6 weeks compared with preoperative measurements (p < 0.0001), a partial recovery at 12 weeks, and a full recovery at 24 weeks. Shoulders that were stiff before surgery were more likely to be stiff at 6, 12, and, to a lesser extent, 24 weeks after surgery (r = 0.10 to 0.31; p < 0.0001). A stiffer shoulder at 6 and 12 weeks (but not 24 weeks) postoperatively correlated with better rotator cuff integrity at 6 months postoperatively (r = 0.11 to 0.18; p < 0.001). The retear rate of patients with ≤20° of external rotation at 6 weeks postoperatively was 7%, while the retear rate of patients with >20° of external rotation at 6 weeks was 15% (p < 0.001). CONCLUSIONS: In patients who developed stiffness after surgery, a rotator cuff repair was more likely to heal. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Iron Polypyridyl Complexes for Photocatalytic Hydrogen Generation.

A series of Fe(III) complexes were recently reported that are stable and active electrocatalysts for reducing protons into hydrogen gas. Herein, we report the incorporation of these electrocatalysts into a photocatalytic system for hydrogen production. Hydrogen evolution is observed when these catalysts are paired with fluorescein (chromophore) and triethylamine (sacrificial electron source) in a 1:1 ethanol:water mixture. The photocatalytic system is highly active and stable, achieving TONs > 2100 (with respect to catalyst) after 24 h. Catalysis proceeds through a reductive quenching pathway with a quantum yield of over 3%.

Schwann cells induce cancer cell dispersion and invasion.

Nerves enable cancer progression, as cancers have been shown to extend along nerves through the process of perineural invasion, which carries a poor prognosis. Furthermore, the innervation of some cancers promotes growth and metastases. It remains unclear, however, how nerves mechanistically contribute to cancer progression. Here, we demonstrated that Schwann cells promote cancer invasion through direct cancer cell contact. Histological evaluation of murine and human cancer specimens with perineural invasion uncovered a subpopulation of Schwann cells that associates with cancer cells. Coculture of cancer cells with dorsal root ganglion extracts revealed that Schwann cells direct cancer cells to migrate toward nerves and promote invasion in a contact-dependent manner. Upon contact, Schwann cells induced the formation of cancer cell protrusions in their direction and intercalated between the cancer cells, leading to cancer cell dispersion. The formation of these processes was dependent on Schwann cell expression of neural cell adhesion molecule 1 (NCAM1) and ultimately promoted perineural invasion. Moreover, NCAM1-deficient mice showed decreased neural invasion and less paralysis. Such Schwann cell behavior reflects normal Schwann cell programs that are typically activated in nerve repair but are instead exploited by cancer cells to promote perineural invasion and cancer progression.

Pattern of neck recurrence after lateral neck dissection for cervical metastases in papillary thyroid cancer.

BACKGROUND: The objective of this study was to determine the rate and pattern of nodal recurrence in patients who underwent a therapeutic, lateral neck dissection (LND) for papillary thyroid cancer (PTC) with clinically evident cervical metastases and to determine if there was any correlation between the extent of initial dissection and the rate and pattern of neck recurrence. METHODS: A total of 3,664 patients with PTC treated between 1986 and 2010 at Memorial Sloan Kettering Cancer Center were identified from our institutional database. Tumor factors, patient demographics, extent of initial LND, and adjuvant therapy were recorded. Patterns of recurrent lateral neck metastases by level involvement were recorded and outcomes calculated using the Kaplan-Meier method. RESULTS: A total of 484 patients had an LND for cervical metastases; 364 (75%) had a comprehensive LND (CLND) and 120 (25%) had a selective neck dissection (SND). The median duration of follow-up was 63.5 months. As expected, patients with CLND had a greater number of nodes removed as well as a greater number of positive nodes (P < .001). There was no difference in overall lateral neck recurrence-free status (CLND 94.4% vs SND 89.4%, P = .158), but in the dissected neck, the ipsilateral lateral neck recurrence-free status was superior in the CLND patients (97.7% vs 89.4%, P < .001). CONCLUSION: Patients with clinically evident neck metastases from PTC managed by CLND have lesser rates of recurrence in the dissected neck compared with patients managed by SND. SND should only be done in highly selected cases with small volume disease.

Hydrogen evolution catalyzed by a cobalt complex containing an asymmetric Schiff-base ligand.

A cobalt(iii) complex containing an asymmetric Schiff-base ligand has been found to be active for proton reduction. Catalysis occurs at -1.2 V vs. Fc(+)/Fc (0.56 V vs. NHE), resulting in an overpotential of 350 mV. Additionally, the complex is active with a turnover frequency of 420 s(-1). An enhancement in activity is observed upon addition of water.

A nickel complex of a conjugated bis-dithiocarbazate Schiff base for the photocatalytic production of hydrogen.

We report a nickel complex containing a conjugated bis-dithiocarbazate ligand that is an active catalyst for the reduction of protons into hydrogen gas. Light-driven hydrogen generation is observed from a system containing this molecular nickel catalyst coupled with a fluorescein photosensitizer and triethylamine sacrificial donor. The photocatalytic system is stable for over 70 hours, achieving 3300 turnovers with respect to catalyst. The complex is also an active electrocatalyst for proton reduction with catalysis occurring at -1.7 V vs. Fc(+)/Fc. The nickel bis-dithiocarbazate complex represents a highly active and stable catalyst for hydrogen generation.

Sulfinato iron(III) complex for electrocatalytic proton reduction.

We report the first example of a sulfinato Fe(III) complex acting as a highly active electrocatalyst for proton reduction. The sulfinate binds to the metal through oxygen, resulting in a seven-membered chelate ring that is likely hemilabile during catalysis. Proton reduction occurs at -1.57 V versus Fc/Fc(+) in CH3CN with an ic/ip = 13 in CH3CN (kobs = 3300 s(-1)) and an overpotential of 800 mV. The catalysis is first order with respect to [catalyst] and second order with respect to [trifluoracetic acid]. An 11% increase in catalytic activity is observed in the presence of water, suggesting that sulfinate moieties are viable functional groups for aqueous proton reduction catalysts.

The chemokine (CCL2-CCR2) signaling axis mediates perineural invasion.

UNLABELLED: Perineural invasion is a form of cancer progression where cancer cells invade along nerves. This behavior is associated with poor clinical outcomes; therefore, it is critical to identify novel ligand-receptor interactions between nerves and cancer cells that support the process of perineural invasion. A proteomic profiler chemokine array was used to screen for nerve-derived factors secreted from tissue explants of dorsal root ganglion (DRG), and CCL2 was identified as a lead candidate. Prostate cancer cell line expression of CCR2, the receptor to CCL2, correlated closely with MAPK and Akt pathway activity and cell migration towards CCL2 and DRG. In vitro nerve and cancer coculture invasion assays of perineural invasion demonstrated that cancer cell CCR2 expression facilitates perineural invasion. Perineural invasion is significantly diminished in coculture assays when using DRG harvested from CCL2(-/-) knockout mice as compared with control CCL2(+/+) mice, indicating that CCR2 is required for perineural invasion in this murine model of perineural invasion. Furthermore, 20 of 21 (95%) patient specimens of prostate adenocarcinoma with perineural invasion exhibited CCR2 expression by immunohistochemistry, while just 3 of 13 (23%) lacking perineural invasion expressed CCR2. In summary, nerve-released CCL2 supports prostate cancer migration and perineural invasion though CCR2-mediated signaling. IMPLICATIONS: These results reveal CCL2-CCR2 signaling as a key ligand-receptor mechanism that mediates cancer cell communication with nerves during perineural invasion and highlight a potential future therapeutic target.

Cobalt complexes as artificial hydrogenases for the reductive side of water splitting.

The generation of H2 from protons and electrons by complexes of cobalt has an extensive history. During the past decade, interest in this subject has increased as a result of developments in hydrogen generation that are driven electrochemically or photochemically. This article reviews the subject of hydrogen generation using Co complexes as catalysts and discusses the mechanistic implications of the systems studied for making H2. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.

Cobalt-dithiolene complexes for the photocatalytic and electrocatalytic reduction of protons in aqueous solutions.

Artificial photosynthesis (AP) is a promising method of converting solar energy into fuel (H(2)). Harnessing solar energy to generate H(2) from H(+) is a crucial process in systems for artificial photosynthesis. Widespread application of a device for AP would rely on the use of platinum-free catalysts due to the scarcity of noble metals. Here we report a series of cobalt dithiolene complexes that are exceptionally active for the catalytic reduction of protons in aqueous solvent mixtures. All catalysts perform visible-light-driven reduction of protons from water when paired with Ru(bpy)(3)(2+) as the photosensitizer and ascorbic acid as the sacrificial donor. Photocatalysts with electron withdrawing groups exhibit the highest activity with turnovers up to 9,000 with respect to catalyst. The same complexes are also active electrocatalysts in 11 acetonitrile/water. The electrocatalytic mechanism is proposed to be ECEC, where the Co dithiolene catalysts undergo rapid protonation once they are reduced to CoL(2)(2-). Subsequent reduction and reaction with H(+) lead to H(2) formation. Cobalt dithiolene complexes thus represent a new group of active catalysts for the reduction of protons.

A cobalt-dithiolene complex for the photocatalytic and electrocatalytic reduction of protons.

The complex [Co(bdt)(2)](-) (where bdt = 1,2-benzenedithiolate) is an active catalyst for the visible light driven reduction of protons from water when employed with Ru(bpy)(3)(2+) as the photosensitizer and ascorbic acid as the sacrificial electron donor. At pH 4.0, the system exhibits very high activity, achieving >2700 turnovers with respect to catalyst and an initial turnover rate of 880 mol H(2)/mol catalyst/h. The same complex is also an active electrocatalyst for proton reduction in 1:1 CH(3)CN/H(2)O in the presence of weak acids, with the onset of a catalytic wave at the reversible redox couple of -1.01 V vs Fc(+)/Fc. The cobalt-dithiolene complex [Co(bdt)(2)](-) thus represents a highly active catalyst for both the electrocatalytic and photocatalytic reduction of protons in aqueous solutions.

An alternative to open incision and drainage for community-acquired soft tissue abscesses in children.

BACKGROUND: The continually rising incidence of soft tissue abscesses in children has prompted us to seek an alternative to the traditional open incision and drainage (I&D) that would minimize the pain associated with packing during dressing changes and eliminate the need for home nursing care. STUDY DESIGN: A retrospective review of all patients with soft tissue abscesses from November 2007 to June 2008 was conducted after institutional review board approval. Patients who were treated with open I&D were compared to those treated with placement of subcutaneous drains through the abscess cavities. Both groups received equivalent antibiotic treatment, and all patients were followed in outpatient clinics until infection resolved. The demographics, presenting temperature, culture results, and outcomes were compared between these 2 groups. RESULTS: A total of 219 patients were identified; 134 of them underwent open I&D, whereas 85 were treated with subcutaneous drains. The demographics, anatomical location of the abscesses, and bacteriology were comparable between the 2 groups. There were equal number of patients in each group who presented with fever initially. Of those treated with open I&D, 4 had metachronous recurring abscesses within the same anatomical region and 1 patient required an additional procedure because of incomplete drainage. There were no recurrences or incomplete drainages in the subcutaneous drain group. The cosmetic appearance of the healed wound from subcutaneous drain placement during the immediate follow-up period is better than that of an open I&D. CONCLUSIONS: Placement of a subcutaneous drain for community-acquired soft tissue abscesses in children is a safe and equally effective alternative to the traditional I&D.

Outcome differences between gastroschisis repair methods.

BACKGROUND: Gastroschisis is a congenital abdominal wall defect that is repaired with either a primary closure or staged closure. The outcome of these infants may differ because of different closure techniques. In addition to the usual markers of parenteral nutrition (PN) use and length of stay (LOS) as outcome measures, we examined the duration of postoperative acidosis and positive fluid balance as markers for postoperative stress associated with these two techniques. METHODS: A retrospective review of newborns with gastroschisis was conducted at a free-standing children's hospital from 2002 to 2008. The demographic data, gestational age, birth weight, operative reports, days on PN, LOS, duration of postoperative acidosis and fluid balances were reviewed. Data were analyzed using the Fisher's exact test or unpaired t test. RESULTS: Thirty-two infants with gastroschisis were identified. One was excluded from analysis due to incomplete follow-up. The patients were classified as either primary closure (n = 8) or staged repair (n = 23). There was one death in our series. Patients who underwent primary closure had significantly older gestational age and higher birth weight. Primary closure is associated with significantly less duration of postoperative metabolic acidosis and fewer days with positive fluid balance. Patients who had primary repair also had less parenteral nutrition use and shorter length of hospitalization, though not statistically significant. Gastroschisis with associated intestinal atresia was more likely to be repaired with staged closures. CONCLUSIONS: There are physiologic advantages to primary repair of gastroschisis that can lead to better outcome, but the indications for the choices of closure technique remain unclear. Primary closure should be used when possible.

Staphylococcal colonization of caretakers of children who have community-acquired skin and soft tissue infections.

PURPOSE: Colonization with Staphylococcus aureus is considered a risk factor for the rising incidence of pediatric community-acquired skin and soft tissue infections (CA-SSTIs), and intrafamily spread is thought to be the source of colonization. METHODS: A prospective study was conducted to determine skin and nasal staphylococcal colonization rates among the caretakers of CA-SSTI patients and those of nonabscess controls. A questionnaire regarding risk factors was administered to all participants. Fisher's Exact test and the chi(2) test were used for statistical analysis. RESULTS: Forty-six patients and their caretakers were enrolled in both the study and control groups. Of the caretakers in the study group, 19.6% (n = 9) had staphylococcal colonization of nares; and 2.2% (n = 1), skin. In the control group, 17.4% (n = 8) had nasal colonization; and none had skin colonization. Of the children in the study group, 58.7% (n = 27) had a family history of CA-SSTI compared with only 17.4% (n = 8) of controls (P = .0001). Of CA-SSTI patients, 45.7% (n = 21) had prior abscesses compared with 6.5% (n = 3) of controls (P = .0001). No other risk factor was identified. CONCLUSION: There was no increase in nasal or skin staphylococcal colonization among caretakers of children with CA-SSTI. Family and personal histories of CA-SSTI were the only identified risk factors for CA-SSTI.