Lateral clavicle fracture with coracoclavicular ligament injury: a biomechanical study of 4 different repair techniques

Purpose

To investigate the biomechanical performance of four different methods used for coracoclavicular (CC) ligament reconstruction in a lateral clavicle fracture repair.

Methods

Native displacement, translation, and rotation at the acromioclavicular joint of 24 fresh-frozen cadaveric shoulders were tested. A reproducible fracture in the lateral third of the clavicle was created by dissecting both CC ligaments. Each specimen was then repaired with plate fixation of the fracture and the following CC repair technique: (1) Cortical button. (2) Suture anchor and plate button. (3) Suture anchor no plate button, and (4) Suture around coracoid. All reconstructed specimens were then re-tested for displacement, translation, and load to failure, and compared to their native results. Groups 1 and 3 were investigated for rotational load.

Results

There was no difference in load to failure between the repaired groups (p: ns). Group 1 showed less superior and anterior translations (p?<?0.05). Group 2 showed significantly less superior translation (p?=?0.003), but no significance with anterior and posterior translations to the native joint. Group 3 showed less superior and posterior translations (p?=?0.005 and p?=?0.039). Anterior and posterior translations were increased in group 4 (p?<?0.05).

Conclusion

The biomechanical analyses did not show any significance in load to failure or displacement after cyclic loading among the study groups. All repairs were effective in preventing superior translation. Groups 1 and 2 demonstrated increased horizontal stability compared to the native state. All 4 methods are clinically viable options for CC ligament repair.

     

Plasmid-based vaccination with candidate anthrax vaccine antigens induces durable type 1 and type 2 T-helper immune responses

The current anthrax vaccine imparts protective immunity by generating a humoral immune response against a single antigen, the PA exotoxin subunit. While this response neutralizes the two anthrax exotoxins and protects the recipient from toxin-related mortality, the recipient is not protected from spore germination, infection, and/or bacteremia. Moreover, protective immunity against PA must be generated via a lengthy injection schedule and maintained by a yearly booster. In an effort to improve upon the current vaccine formulation, we screened six of seven known virulence factors encoded by Bacillus anthracis epigenetic elements pXO1 and pXO2 as well as the major surface proteins EA1 and SAP. Screening was carried out in conjunction with a plasmid-based technology known for its ability to generate type 1 and type 2 T-helper responses. Long-term high level antibody titers were generated against the products of eag (EA1), sap (SAP), and the capA capsule synthesis subunit in vivo. Further analysis of PA- and EA1-vaccinated mice demonstrated antigen-specific type 1 helper responses including IFN-gamma secretion and lysis of EA1- or PA-loaded macrophages; further, an EA1 T-cell epitope was identified. The results demonstrate that anthrax antigens other than PA might be suitable for the generation of durable immune responses against anthrax.     

Effects of garlic supplementation on liver enzymes: A systematic review and meta‐analysis of randomized controlled trials

Current evidence on the beneficial effects of garlic on liver enzymes is contradictory. Therefore, the aim of this systematic review and meta‐analysis is to evaluate the effect of garlic supplementation on human liver enzymes, such as Alanine Transaminase (ALT/SGPT) and Aspartate Transaminase (AST/SGOT). To collect the required data, PubMed, Scopus, ISI Web of Science, and Google scholar databases were systematically searched from inception to June 2019. A meta‐analysis was conducted using the random‐effects model to evaluate the effects of garlic supplementation on ALT and AST levels. The Cochran's Q‐test and inconsistency index were also used to evaluate heterogeneity among the studies. Among a total of 15,514 identified articles, six studies (containing 301 participants) met the inclusion criteria. Results of the meta‐analysis showed that garlic supplementation significantly decreased AST level (Hedges' g = ?0.36, 95% confidence interval [CI]: ?0.72, ?0.004, p = .047); whereas, it had no significant effect on ALT level (Hedges' g = ?0.22, 95% CI: ?0.64, 0.20, p = .310). Results showed that garlic supplementation reduced AST levels significantly; however, had no significant effect on ALT levels. Further studies are still needed to confirm the results.     

Crystalline silica dust and respirable particulate matter during indoor concrete grinding - wet grinding and ventilated grinding compared with uncontrolled conventional grinding

The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field.     

Murine supraspinatus tendon injury model to identify the cellular origins of rotator cuff healing

ABSTRACT

Purpose of this study: To elucidate the origin of cell populations that contribute to rotator cuff healing, we developed a mouse surgical model where a full-thickness, central detachment is created in the supraspinatus. Materials and methods: Three different inducible Cre transgenic mice with Ai9-tdTomato reporter expression (PRG4-9, αSMA-9, and AGC-9) were used to label different cell populations in the shoulder. The defect was created surgically in the supraspinatus. The mice were injected with tamoxifen at surgery to label the cells and sacrificed at 1, 2, and 5 weeks postoperatively. Frozen sections were fluorescently imaged then stained with Toluidine Blue and re-imaged. Results: Three notable changes were apparent postoperatively. (1) A long thin layer of tissue formed on the bursal side overlying the supraspinatus tendon. (2) The tendon proximal to the defect initially became hypercellular and disorganized. (3) The distal stump at the insertion underwent minimal remodeling. In the uninjured shoulder, tdTomato expression was seen in the tendon midsubstance and paratenon cell on the bursal side in PRG4-9, in paratenon, blood vessels, and periosteum of acromion in SMA-9, and in articular cartilage, unmineralized fibrocartilage of supraspinatus enthesis, and acromioclavicular joint in AGC-9 mice. In the injured PRG4-9 and SMA-9 mice, the healing tissues contained an abundant number of tdTomato+ cells, while minimal contribution of tdTomato+ cells was seen in AGC-9 mice. Conclusions: The study supports the importance of the bursal side of the tendon to rotator cuff healing and PRG4 and αSMA may be markers for these progenitor cells.     

Evaluation of genitofemoral nerve donor site morbidity after radical prostatectomy

BACKGROUND: The sural nerve is commonly used as a donor site for cavernous nerve grafting. However, the genitofemoral nerve is accessible and easily dissected and may represent an improved donor site for this procedure. METHODS: Fourteen patients underwent radical prostatectomy followed by cavernous nerve grafting using the genitofemoral nerve. Seventeen donor sites (3 patients underwent bilateral grafts) were assessed by questionnaires (including the McGill Pain Scale) and focused neurologic examination. RESULTS: Residual numbness in the genitofemoral nerve distribution was noted in 9 of 17 donor sites (53%). No patients reported that the deficits interfered with normal daily activities. All patients denied the presence of burning, cold sensitivity, or pain. All patients scored 0 on each of the 3 pain rating components of the short form McGill Pain questionnaire (sensory, affective, or total). Furthermore, no patients documented pain on either the PPI or VAS portions of the questionnaire. On examination, patients were unable to discriminate between sharp versus dull stimuli in 3 donor sites (17.6%), while 7 donor sites (41.2%) showed decreased light-touch sensation. The Semmes-Weinstein testing demonstrated that 8 (47.1%) were found to have distinct areas with sensory deficit ranging in size from 23 to 63 cm (mean, 16.6 cm). The highest-pressure thresholds for each of the 17 donor sites ranged from 3.61 to 6.45 g/mm (mean, 4.91 g/mm). The mean pressure threshold for the control regions (n=11) was 3.35 g/mm (range, 2.38--4.71 g/mm, P=0.014). Only 50% of the sensory deficits documented by the Semmes-Weinstein test were clinically apparent to the patients. CONCLUSIONS: Due to its low donor site morbidity, the genitofemoral nerve is an excellent donor source for cavernous nerve grafting during radical prostatectomy. In the majority of the patients, the sensory deficit produced by resection of this nerve is minimal and caused no other adverse symptoms. Harvest of this nerve prevents the additional morbidity associated with a donor site located elsewhere on the body (ie, sural nerve).     

The association between total and positive lymph node counts, and disease progression in clinically localized prostate cancer

PURPOSE: We examined the association between the number of LNs removed, the number of positive LNs and disease progression in patients undergoing pelvic lymph node dissection and radical retropubic prostatectomy for clinically localized prostate cancer. MATERIALS AND METHODS: We analyzed 5,038 consecutive patients who underwent radical retropubic prostatectomy between 1983 and 2003. Clinicopathological parameters, including the administration of neoadjuvant hormonal therapy, preoperative prostate specific antigen, specimen Gleason score, surgeon and pathological stage, were collected prospectively in our prostate cancer database. We excluded men treated with radiation or chemotherapy before surgery. BCR was defined as 2 postoperative prostate specific antigen increases greater than 0.2 ng/ml. Cox models were used to determine whether the number of nodes removed or the number of positive nodes predicted freedom from BCR after adjustment for prognostic covariates. RESULTS: The 4,611 eligible patients had a median of 9 LNs (IQR 5 to 13) removed. Positive nodes were found in 175 patients (3.8%). Overall the number of LNs removed did not predict freedom from BCR (HR per additional 10 nodes removed 1.02, 95% CI 0.92 to 1.13, p = 0.7). Results were similar in patients receiving and not receiving neoadjuvant hormonal therapy. Finding any LN involvement was associated with a BCR HR of 5.2 (95% CI 4.2 to 6.4, p <0.0005). However, in men without nodal involvement an increased number of nodes removed correlated significantly with freedom from BCR (p = 0.01). CONCLUSIONS: Nodal disease increased the risk of progression. Extensive lymphadenectomy enhances the accuracy of surgical staging. However, we were unable to determine that removing more nodes improves freedom from BCR uniformly. Since the proportion of patients with prostate cancer with positive nodes is low, the value of extensive lymphadenectomy requires a multi-institutional, randomized clinical trial.     

Efficient ROSA26-Based Conditional and/or Inducible Transgenesis Using RMCE-Compatible F1 Hybrid Mouse Embryonic Stem Cells

The conditional Cre/loxP system and/or the doxycycline (Dox) inducible Tet-on/off system are widely used in mouse transgenesis but often require time consuming, inefficient cloning/screening steps and extensive mouse breeding strategies. We have therefore developed a highly efficient Gateway- and recombinase-mediated cassette exchange (RMCE)-compatible system to target conditional and/or inducible constructs to the ROSA26 locus of F1 hybrid Bl6/129 ESCs, called G4 ROSALUC ESCs. By combining the Cre/loxP system with or without the inducible Tet-on system using Gateway cloning, we can rapidly generate spatial and/or temporal controllable gain-of-function constructs that can be targeted to the RMCE-compatible ROSA26 locus of the G4 ROSALUC ESCs with efficiencies close to 100 %. These novel ESC-based technologies allow for the creation of multiple gain-of-function conditional and/or inducible transgenic ESC clones and mouse lines in a highly efficient and locus specific manner. Importantly, incorporating insulator sequences into the Dox-inducible vector system resulted in robust, stable transgene expression in undifferentiated ESCs but could not fully overcome transgene mosaicism in the differentiated state.