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Abstract Background Prescription of testosterone replacement therapy (TRT) has increased in the United States in recent years, and though anabolic steroids have been associated with tendon rupture, there is a paucity of literature evaluating the risk of Achilles tendon injury with TRT. This study aims to evaluate the associative relationship between consistent TRT, Achilles tendon injury, and subsequent surgery. Methods This is a one‐to‐one matched retrospective cohort study utilizing the PearlDiver database. Records were queried for patients aged 35–75 who were prescribed at least 3 consecutive months of TRT between January 1, 2010 and December 31, 2019. Achilles tendon injuries and subsequent surgeries were identified using ICD‐9, ICD‐10, and CPT billing codes. Multivariable logistic regression was used to compare odds of Achilles tendon injury, Achilles tendon surgery, and revision surgery, with a p‐value

Abstract Efforts to characterize microbial life across diverse environments have progressed tremendously, yet the microbiome of Earth's largest biomass reservoir—the wood of living trees—has been largely unexplored. Current understanding of the tree microbiome is largely confined to roots and leaves, with little attention given to the endophytic microbiome of wood, even though emergent studies have indicated this zone as a niche for unique taxa, of consequence for ecosystem health and global biogeochemical cycles. The lack of investigation derives partly from the physical recalcitrance of wood, which presents challenges during sampling, homogenization, and the extraction of nucleic acids. In response to these issues, we present an optimized method for processing wood for use in microbial analyses, from sampling through to downstream analyses. Using methane‐cycling taxa as model endophytes, we assess losses in recovery during our method, and determine a limit‐of‐detection of approximately 500 cells per 100 mg of (dry) wood. For all six species evaluated—which represented several diverse taxa of hardwoods and softwoods—PCR inhibition proved minimal, and we expect this method to be applicable for a majority of tree species. The methods presented herein can facilitate future investigation into the wood microbiome and global microbial ecology of methane cycling.

Abstract Mitochondrial dysfunction alters cellular metabolism, increases tissue oxidative stress, and may be principal to the dysregulated signaling and function of CD4+ T lymphocytes in the elderly. In this proof of principle study, it is investigated whether the transfer of functional mitochondria into CD4+ T cells that are isolated from old mice (aged CD4+ T cells), can abrogate aging‐associated mitochondrial dysfunction, and improve the aged CD4+ T cell functionality. The results show that the delivery of exogenous mitochondria to aged non‐activated CD4+ T cells led to significant mitochondrial proteome alterations highlighted by improved aerobic metabolism and decreased cellular mitoROS. Additionally, mito‐transferred aged CD4+ T cells showed improvements in activation‐induced TCR‐signaling kinetics displaying markers of activation (CD25), increased IL‐2 production, enhanced proliferation ex vivo. Importantly, immune deficient mouse models (RAG‐KO) showed that adoptive transfer of mito‐transferred naive aged CD4+ T cells, protected recipient mice from influenza A and Mycobacterium tuberculosis infections. These findings support mitochondria as targets of therapeutic intervention in aging.

Abstract Brassicaceae plants have the glucosinolate–myrosinase defense system, jointly active against herbivory. However, constitutive glucosinolate (GLS) defense is observed to occur at levels that do not deter all insects from feeding. That prompts the question of why Brassicaceae plants have not evolved a higher constitutive defense. The answer may lie in the contrasting relationship between plant defense and host plant preference of specialist and generalist herbivores. GLS content increases a plant's susceptibility to specialist insects. In contrast, generalists are deterred by the plant GLSs. Although GLSs can attract the natural enemies (predators and parasitoids) of these herbivores, enemies can reduce herbivore pressure to some extent only. So, plants can be overrun by specialists if GLS content is too high, whereas generalists can invade the plants if it is too low. Therefore, an optimal constitutive plant defense can minimize the overall herbivore pressure. To explain the optimal defense theoretically, we model the contrasting host selection behavior of insect herbivores and the emergence of their natural enemies by non‐autonomous ordinary differential equations, where the independent variable is the plant GLS concentration. From the model, we quantify the optimal amount of GLSs, which minimizes total herbivore (specialists and generalists) pressure. That quite successfully explains the evolution of constitutive defense in plants from the perspective of optimality theory.

Abstract Introduction The discovery of biogenic aldehydes in the postmortem parkinsonian brain and the ability of these aldehydes to modify and cross‐link proteins has called attention to their possible role in Parkinson's disease. For example, many in vitro studies have found that the aldehyde metabolite of dopamine, 3,4‐dihydroxyphenylacetaldehyde (DOPAL), induces the formation of stable, neurotoxic alpha‐synuclein oligomers. Methods To study this in vivo, mice deficient in the two aldehyde dehydrogenase enzymes (Aldh1a1 and Aldh2, DKO) primarily responsible for detoxification of DOPAL in the nigrostriatal pathway were crossed with mice that overexpress human wild‐type alpha‐synuclein. DKO overexpressing human wild‐type alpha‐synuclein (DKO/ASO) offspring were evaluated for impairment on motor tasks associated with Parkinsonism. Results DKO/ASO mice developed severe motor deficits greater than that of mice overexpressing human wild‐type alpha‐synuclein alone. Conclusion These results provide evidence to support the idea that biogenic aldehydes such as DOPAL interact with human wild‐type alpha‐synuclein, directly or indirectly, in vivo to exacerbate locomotor deficits in Parkinson's disease.

Abstract Savannas are characterized by the coexistence of grasses and trees. Fires are critical for their coexistence, because they decrease the survival of tree seedlings and saplings and their recruitment to the adult stage. In some humid savannas, perennial grasses inhibit nitrification and trees stimulate nitrification, which likely favors coexistence between trees and grasses. However, fires may influence plant capacity to control nitrogen cycling, which could subsequently influence tree–grass coexistence and savanna nitrogen budget. Therefore, we sampled soil in a humid savanna of Ivory Coast under the dominant nitrification‐inhibiting grass species and the dominant nitrification‐stimulating tree species and under bare soil before and after (i.e., 5 days) fire during the long dry season. We quantified the total microbial and nitrifier abundances and transcriptional activities and the nitrification enzyme activity. Fire decreased soil water content, probably by increasing evaporation and, maybe, by triggering the growth of grasses, and increased soil ammonium availability likely due to ash deposition and increased mineralization. Fire did not impact the total archaeal, bacterial, or fungal abundances, or that of the nitrifiers. Fire did not impact archaeal transcriptional activity and increased bacterial and fungal total transcriptional activities. In contrast, fire decreased the archaeal nitrifier transcriptional activities and the nitrification enzymatic activity, likely due to the often reported resumption of the growth of nitrification‐inhibiting grasses quickly after the fire (and the subsequent increase in root exudation). These results pave the way for a better understanding of the short‐term effects of fire on nitrogen cycling and tree–grass competition for nitrogen.

Abstract Induced responses in plants, initiated by herbivory, create potential for trait‐mediated indirect interactions among herbivores. Responses to an initial herbivore may change a number of plant traits that subsequently alter ecological processes with additional herbivores. Although common, indirect interactions between taxonomically distant herbivores, such as mammals and insects, are less studied than between taxonomically related species (i.e., insect–insect). In terms of mammal–insect interactions, effects on insect numbers (e.g., density) are relatively well studied, whereas effects on performance (e.g., fecundity) are rarely explored. Moreover, few studies have explored mammal–insect interactions on coniferous plants. The aim of this study was to investigate the effect of mammalian induced responses on insect performance. We specifically investigated the effect of moose (Alces alces) browsing on Scots pine (Pinus sylvestris) and subsequent effects on sawfly (Neodiprion sertifer) performance. Sawfly larvae were reared on browsed, clipped, and unbrowsed control pine trees in a controlled field experiment. Afterward, cocoon weight was measured. Needle C:N ratio and di‐terpene content were measured in response to browsing. Sawfly performance was enhanced on trees browsed by moose. Cocoon weight (proxy for fecundity) was 9 and 13% higher on browsed and clipped trees compared to unbrowsed trees. Cocoon weight was weakly related to needle C:N ratio, and browsed trees had lower a C:N ratio compared to unbrowsed trees. Needle di‐terpene content, known to affect sawfly performance, was neither affected by the browsing treatments nor did it correlate with sawfly weight. We conclude that mammalian herbivory can affect insect herbivore performance, with potential consequences for ecological communities and with particular importance for insect population dynamics. The measured plant variables could not fully explain the effect on sawfly performance providing a starting point for the consideration of additional plant responses induced by mammalian browsing affecting insect performance.

Abstract Because of today's advancements in surgical techniques and perioperative management skills, surgeons are beginning to explore the usefulness of the laparoscopic approach in managing periampullary tumors. However, as a result of its innate complexity and associated high surgery‐related complications, its applicability to the general surgical community remains controversial. To date, only retrospective data from high‐volume centers support the safety and feasibility of laparoscopic pancreaticoduodenectomy (Lap PD) for the treatment of benign conditions and malignant periampullary tumors. In addition, various surgical techniques in terms of port placement, dissection, and reconstruction have evolved in different centers depending on the preferred method commonly used by the surgeon through accumulated experience. In our center, we used a stepwise approach and standardized our surgical technique to overcome this technically demanding procedure. A collaborative implementation of video review and analysis, practice training and simulation, operating room didactics, and strict adherence to our stepwise approach in Lap PD, might potentially improve the surgical skills of young hepatobiliary surgeons and possibly overcome the volume‐based learning curve of Lap PD.