Biomechanical analysis of single-incision anatomic repair technique for distal biceps tendon rupture using tunneling device.

Hypothesis: Single-incision biceps tendon repair with an arthrotunneling device has previously been shown to be a safe and effective technique that provides the anatomic restoration of a two-incision approach and a reduced complication profile. This repair provides adequate and comparable fixation to repairs utilizing anchors, buttons, screws, etc., at a lower cost. Material and methods: This study utilized 10 cadaveric specimens. Native and repair specimens were cyclically loaded and graft displacement, flexion/extension (FE) and pronation/supination (PS) moment arms at 12.5° to 152.5° (in 5° increments) before and after repair, and maximum load to failure were measured. Results: The FE and PS moment arms and overall maximum moment arms were both significantly larger in the repaired case than in the native case (p < 0.01). Moment arms for supinated specimens were significantly greater than neutral specimens, which in turn was greater than pronated specimens (p < 0.01). The maximum load up to 10 mm of repair displacement was 214.5.0 ± 66.6 N and the repair displacement due to 1000 cycles of 50 N was 2.56 ± 2.06 mm. Conclusion: The single-incision arthrotunneling technique is a safe and effective repair that recreates the anatomic footprint and biomechanics of the native biceps and has a reduced complication profile compared to a two-incision approach.

Gender and Racial Bias in Letters of Recommendation for Orthopedic Surgery Residency Positions.

OBJECTIVE: The primary purpose of this study was to retrospectively analyze letters of recommendation written for medical students applying to orthopedic residency for implicit race and gender bias. The secondary purpose was to determine if the presence of bias was influenced by the gender of the letter writer. DESIGN: This was a retrospective institutional review board (IRB) approved study. All letters of recommendation received in the years 2016 to 2018 were deidentified and analyzed using the Linguistics Inquiry and Word Count (LIWC) 2015 software. Independent variables in our analysis were applicant gender and applicant race. Dependent study variables included the summary and characteristic variables of a letter of recommendation, which are word count, analytic, clout, authenticity, tone, and positive and negative emotion word categories. Separate analyses were completed by gender of the letter writer as well. SETTING: Institution: Temple University Hospital, Philadelphia, Pennsylvania. PARTICIPANTS: Medical students applying to Temple University Hospital Orthopaedic Surgery Program from 2016 to 2018. A total of 2113 applicants were included in the study. RESULTS: Female, Asian and underrepresented minority applicants' letters were more likely to have a higher word count. In our subset analysis by gender of letter writer, when the letter writer was male, Asian applicants' letters were more likely to convey analytical thinking and authenticity. When the letter writer was male, male applicants scored higher for authenticity. Letters written by female attendings demonstrated no significant difference for male or female applicants in terms of composite variables or word categories. CONCLUSIONS: Our study shows that letters of recommendation for orthopedic surgery residency positions are likely to contain some degree of bias. Further studies are required to fully characterize the degree and magnitude of bias in letters of recommendation and whether the findings of our study are significant enough to contribute to the difference in socioeconomic demographics between orthopedic residents and society at large.

Proximal Tibial Osteotomies: Indications, Techniques, and Outcomes.

High tibial osteotomy (HTO) is a surgical procedure that can be used as a primary or as an adjunctive treatment for a variety of knee pathologies, most commonly isolated medial compartment arthrosis in a knee with varus alignment. More recently, indications for HTO have been expanded to include its use in combination with cartilage preserving techniques, to offload the effected compartment, and in conjunction with ligamentous reconstruction. HTO also has utility in delaying total knee arthroplasty (TKA) in select patients with favorable literature on future TKA outcomes. Numerous techniques for HTO have been published, however, medial opening wedge and lateral closing wedge osteotomies remain the most common. The purpose of this article is to summarize HTO patient selection and indications, surgical techniques, common complications, and review outcomes from recent literature. (Journal of Surgical Orthopaedic Advances 32(3):148-155, 2023).

Distal Radioulnar Joint Instability and Associated Injuries: A Literature Review.

The distal radioulnar joint (DRUJ) allows supination and pronation of the distal forearm and wrist, an integral motion in everyday human activity. DRUJ injury and chronic instability can be a significant source of morbidity in patients' lives. Although often linked with distal radius fractures, DRUJ injury may occur in a variety of other upper extremity injuries, as well as an isolated pathology. Diagnosis of this injury requires the clinician to have a high index of suspicion and low threshold for clinical testing and further imaging of the DRUJ. The purpose of this article is to provide a review on DRUJ anatomy and biomechanics, to discuss common diagnostic and treatment modalities, and to identify common injuries associated with DRUJ instability.

A Metabolomic and HPLC-MS/MS Analysis of the Foliar Phenolics, Flavonoids and Coumarins of the Fraxinus Species Resistant and Susceptible to Emerald Ash Borer.

The Emerald Ash Borer (EAB), Agrilus planipennis, Fairmaire, an Asian invasive alien buprestid has devastated tens of millions of ash trees (Fraxinus spp.) in North America. Foliar phytochemicals of the genus Fraxinus (Oleaceae): Fraxinus pennsylvanica (Green ash), F. americana (White ash), F. profunda (Bush) Bush. (Pumpkin ash), F. quadrangulata Michx. (Blue ash), F. nigra Marsh. (Black ash) and F. mandshurica (Manchurian ash) were investigated using HPLC-MS/MS and untargeted metabolomics. HPLC-MS/MS help identified 26 compounds, including phenolics, flavonoids and coumarins in varying amounts. Hydroxycoumarins, esculetin, esculin, fraxetin, fraxin, fraxidin and scopoletin were isolated from blue, black and Manchurian ashes. High-throughput metabolomics revealed 35 metabolites, including terpenes, secoiridoids and lignans. Metabolomic profiling indicated several upregulated putative compounds from Manchurian ash, especially fraxinol, ligstroside, oleuropin, matairesinol, pinoresinol glucoside, 8-hydroxypinoresinol-4-glucoside, verbenalin, hydroxytyrosol-1-O-glucoside, totarol and ar-artemisene. Further, dicyclomine, aphidicolin, parthenolide, famciclovir, ar-turmerone and myriocin were identified upregulated in blue ash. Principal component analysis demonstrated a clear separation between Manchurian and blue ashes from black, green, white and pumpkin ashes. The presence of defensive compounds upregulated in Manchurian ash, suggests their potential role in providing constitutive resistance to EAB, and reflects its co-evolutionary history with A. planipennis, where they appear to coexist in their native habitats.

Antioxidant Activity of the Lignins Derived from Fluidized-Bed Fast Pyrolysis.

A challenge in recent years has been the rational use of forest and agriculture residues for the production of bio-fuel, biochemical, and other bioproducts. In this study, potentially useful compounds from pyrolytic lignins were identified by HPLC-MS/MS and untargeted metabolomics. The metabolites identified were 2-(4-allyl-2-methoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)-1-propanol, benzyl benzoate, fisetinidol, phenyllactic acid, 2-phenylpropionic acid, 6,3'-dimethoxyflavone, and vanillin. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), trolox equivalent antioxidant capacity (TEAC), and total phenolics content (TPC) per gram of pyrolytic lignin ranged from 14 to 503 mg ascorbic acid equivalents, 35 to 277 mg trolox equivalents, and 0.42 to 50 mg gallic acid equivalents, respectively. A very significant correlation was observed between the DPPH and TPC (r = 0.8663, p ≤ 0.0001), TEAC and TPC (r = 0.8044, p ≤ 0.0001), and DPPH and TEAC (r = 0.8851, p ≤ 0.0001). The polyphenolic compounds in the pyrolytic lignins which are responsible for radical scavenging activity and antioxidant properties can be readily profiled with HPLC-MS/MS combined with untargeted metabolomics. The results also suggest that DPPH, TEAC, and TPC assays are suitable methods for the measurement of antioxidant activity in a variety of pyrolytic lignins. These data show that the pyrolytic lignins can be considered as promising sources of natural antioxidants and value-added chemicals.

Identification of odor-processing genes in the emerald ash borer, Agrilus planipennis.

BACKGROUND: Insects rely on olfaction to locate food, mates, and suitable oviposition sites for successful completion of their life cycle. Agrilus planipennis Fairmaire (emerald ash borer) is a serious invasive insect pest that has killed tens of millions of North American ash (Fraxinus spp) trees and threatens the very existence of the genus Fraxinus. Adult A. planipennis are attracted to host volatiles and conspecifics; however, to date no molecular knowledge exists on olfaction in A. planipennis. Hence, we undertook an antennae-specific transcriptomic study to identify the repertoire of odor processing genes involved in A. planipennis olfaction. METHODOLOGY AND PRINCIPAL FINDINGS: We acquired 139,085 Roche/454 GS FLX transcriptomic reads that were assembled into 30,615 high quality expressed sequence tags (ESTs), including 3,249 isotigs and 27,366 non-isotigs (contigs and singletons). Intriguingly, the majority of the A. planipennis antennal transcripts (59.72%) did not show similarity with sequences deposited in the non-redundant database of GenBank, potentially representing novel genes. Functional annotation and KEGG analysis revealed pathways associated with signaling and detoxification. Several odor processing genes (9 odorant binding proteins, 2 odorant receptors, 1 sensory neuron membrane protein and 134 odorant/xenobiotic degradation enzymes, including cytochrome P450s, glutathione-S-transferases; esterases, etc.) putatively involved in olfaction processes were identified. Quantitative PCR of candidate genes in male and female A. planipennis in different developmental stages revealed developmental- and sex-biased expression patterns. CONCLUSIONS AND SIGNIFICANCE: The antennal ESTs derived from A. planipennis constitute a rich molecular resource for the identification of genes potentially involved in the olfaction process of A. planipennis. These findings should help in understanding the processing of antennally-active compounds (e.g. 7-epi-sesquithujene) previously identified in this serious invasive pest.

Glutathione transferase P1 interacts strongly with the inner leaflet of the plasma membrane.

GSH transferases (GSTs) are a superfamily of proteins best known for detoxifying harmful electrophilic compounds by catalyzing their conjugation with GSH. GSTP1 is the most prevalent and widely distributed GST in human tissues, helping to detoxify a diverse array of carcinogens and drugs. In contrast with its protective role, overexpression of GSTP1 in a variety of malignancies is associated with a poor prognosis due to failure of chemotherapy. Although GSTP1 is classified as a cytosolic GST, we discovered previously that it is associated with the plasma membrane of the small cell lung cancer cell lines, H69 and H69AR. In the current study, endogenous and overexpressed GSTP1 in human embryonic kidney (HEK) 293 and MCF-7 cell lines, respectively, were found also to associate with the plasma membrane, indicating that this interaction is not unique to H69 and H69AR cells. GSTP1 immunostaining in HEK293 and MCF7-GSTP1 cells only occurred under permeabilized conditions, suggesting that GSTP1 is associated with the intracellular surface of the plasma membrane. Cell surface biotinylation studies confirmed this finding. Immunogold electron microscopy revealed the presence of GSTP1 in close proximity to the plasma membrane. GSTP1 was not dissociated from plasma membrane sheets by high salt [potassium iodide (KI; 1 M) or KI/EDTA (1 M/2 mM)] or alkaline Na(2)CO(3) (100 mM, pH 11.4), conditions known to strip peripherally associated membrane proteins. Thus, we report for the first time that GSTP1 is associated with the inner leaflet of the plasma membrane through a remarkably strong interaction.

Addition of exogenous carbon and nitrogen sources to aphid exuviae modulates synthesis of proteases and chitinase by germinating conidia of Beauveria bassiana.

Secretion of catabolic extracellular enzymes (ECE) is the hallmark of the infection of insects through the cuticle by entomopathogenic fungi (EPF). In this paper, we show that germinating conidia of Beauveria bassiana (Bb) regulate the synthesis of ECE through a multiple control mode during the initial stages of germination. We tested Bb conidial growth on aphid exuviae with or without supplementation of additional carbon and/or nitrogen (C/N) compounds. To understand the interrelation between conidial germination during growth, the synthesis of ECE activity, free amino nitrogen (FAN), glucose and fungal dry weight biomass were measured. Immediately (0.25 h) upon incubation of conidia, activity of subtilisin-like Pr1 and trypsin-like Pr2 enzymes and chitinase (NAGase) was observed in the culture filtrates. At 0.25 h, addition of exogenous C-source resulted in higher activities of Pr1 and Pr2, respectively. Conversely at 0.25 h, addition of N-sources repressed the synthesis of Pr2, but that of Pr1. C/N repression was observed only for exponentially growing mycelia. NAGase activity remained at basal level and unaffected by added C/N. We conclude that C/N repression occurs only when it is necessary for the Bb infective structures to establish a nutritional relationship with the host structures.

Hydrated conidia of Metarhizium anisopliae release a family of metalloproteases.

Metarhizium anisopliae spores release isoforms of metalloprotease during hydration over a 4-day incubation period. The isoforms were identified and characterized by using one-dimensional native PAGE (1-DE nPAGE) and one-dimensional SDS non-dissociating (1-DE nSDS-PAGE) zymography. The ability of these isozymes to degrade gelatin varied as revealed by 2-D spot densitometry. 1-DE nPAGE zymography revealed five isoforms of gelatinase from Tween wash of conidia. Where as, one to three activities with different intensities appeared on gel from washing of conidia to incubation in water till day 4. The relative migrations of these activities on 1-DE nPAGE zymograms appeared as fast, medium and slow on gel. The 2-D spot densitometry of zymograms indicated isoforms have different proteolytic activity as quantified by pixel intensities. SDS-PAGE zymography indicated the release of two isozymes of Mr 103 and 12 kDa during Tween treatment of conidia. However, during the first washing step with water and incubation of spores at day 2 and 3, respectively, only 12 kDa protein was evident. Majority of these proteases were inhibited by EDTA, but stimulated by CaCl(2), and MgCl(2). The presence of isozymes in conidia and their release during hydration must have functional significance for fungi and in this case it should provide advantages to M. anisopliae in its saprobic or pathogenic modalities. To our knowledge this is the first report describing release of metalloprotease isozymes from conidia.