Publications by authors named "Ryan Montalvo"

As global temperatures rise, heat-related chronic health disorders are predicted to become more prevalent. We tested whether a single exposure to acute heat illness, using a preclinical mouse model of exertional heat stroke (EHS), can induce late-emerging health disorders that progress into chronic disease. Following EHS, mice were followed for 3 months; after two weeks of recovery, half were placed on a Western diet to determine if previous EHS exposure amplifies the negative consequences of an atherogenic diet.

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Doxorubicin (DOX) is a highly effective anthracycline antibiotic used to treat a wide variety of cancers including breast cancer, leukemia and lymphoma. Unfortunately, clinical use of DOX is limited due to adverse off-target effects resulting in fatigue, respiratory muscle weakness and dyspnea. The diaphragm is the primary muscle of inspiration and respiratory insufficiency is likely the result of both muscle weakness and neural impairment.

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Doxorubicin (DOX) is a highly effective chemotherapy agent prescribed for cancer treatment. However, the clinical use of DOX is limited due to off-target toxicity in healthy tissues. In this regard, hepatic and renal metabolic clearance results in DOX accumulation within these organ systems.

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Doxorubicin (DOX) is a chemotherapeutic agent highly effective at limiting cancer progression. Despite the efficacy of this anticancer drug, the clinical use of DOX is limited due to cardiotoxicity. The cardiac mitochondria are implicated as the primary target of DOX, resulting in inactivation of electron transport system complexes, oxidative stress, and iron overload.

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Cardiorespiratory dysfunction resulting from doxorubicin (DOX) chemotherapy treatment is a debilitating condition affecting cancer patient outcomes and quality of life. DOX treatment promotes cardiac and respiratory muscle pathology due to enhanced reactive oxygen species (ROS) production, mitochondrial dysfunction and impaired muscle contractility. In contrast, hyperbaric oxygen (HBO) therapy is considered a controlled oxidative stress that can evoke a substantial and sustained increase in muscle antioxidant expression.

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Background: Next-generation DNA sequencing (NGS) detects bacteria-specific DNA corresponding to the 16S ribosomal RNA gene and can identify bacterial presence with greater accuracy than traditional culture methods. The clinical relevance of these findings is unknown. The purpose of the present study was to compare the results from bacterial culture and NGS in order to characterize the potential use of NGS in orthopaedic trauma patients.

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Article Synopsis
  • Despite the common use of antibiotics, surgical site infections remain prevalent in patients with fractures, prompting the need to explore better prevention methods.
  • An open-label randomized clinical trial tested the impact of intrawound vancomycin powder on reducing deep surgical site infections in high-risk patients undergoing tibial plateau or pilon fracture surgeries across multiple US trauma centers.
  • Results showed that the treatment group had a lower incidence of deep infections (6.4%) compared to the control group (9.8%), with the vancomycin specifically showing a significant effect on gram-positive infections, indicating its potential as an effective intervention in surgical settings.
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Doxorubicin (DOX) is an anthracycline antibiotic used to treat a wide variety of hematological and solid tumor cancers. While DOX is highly effective at reducing tumor burden, its clinical use is limited by the development of adverse effects to both cardiac and skeletal muscle. The detrimental effects of DOX to muscle tissue are associated with the increased incidence of heart failure, dyspnea, exercise intolerance, and reduced quality of life, which have been reported in both patients actively receiving chemotherapy and cancer survivors.

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Doxorubicin (DOX) is a highly effective chemotherapeutic agent used in the treatment of various cancer types. Nevertheless, it is well known that DOX promotes the development of severe cardiovascular complications. Therefore, investigation into the underlying mechanisms that drive DOX-induced cardiotoxicity is necessary to develop therapeutic countermeasures.

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Background: Subtrochanteric femur fractures associate with a relatively high complication rate and are traditionally treated operatively with a period of limited weight bearing. Transitioning from extramedullary to intramedullary implants, there are increasing biomechanical and clinical data to support early weight bearing. This multicenter retrospective study examines the effect of postoperative weight bearing as tolerated (WBAT) for subtrochanteric femur fractures.

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Clinical use of the chemotherapeutic doxorubicin (DOX) promotes skeletal muscle atrophy and weakness, adversely affecting patient mobility and strength. Although the mechanisms responsible for DOX-induced skeletal muscle dysfunction remain unclear, studies implicate the significant production of reactive oxygen species (ROS) in this pathology. Supraphysiological ROS levels can enhance protein degradation via autophagy, and it is established that DOX upregulates autophagic signaling in skeletal muscle.

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Introduction: Cancer cachexia is characterized by severe skeletal muscle mass loss, which is driven by decreased muscle protein synthesis and increased protein degradation. Daily physical activity and feeding behaviors exhibit diurnal fluctuations in mice that can impact the systemic environment and skeletal muscle signaling.

Purpose: We investigated the effect of cancer cachexia on the diurnal regulation of feeding, physical activity, and skeletal muscle mechanistic target of rapamycin complex 1 (mTORC1) signaling in tumor-bearing mice.

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Doxorubicin (DOX) is a highly effective antineoplastic agent used in cancer treatment. Unfortunately, clinical use of DOX is limited due to the development of dose-dependent toxicity to cardiac and respiratory (i.e.

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New Findings: What is the central question of this study? Interleukin-6 has been associated with muscle mass and metabolism in both physiological and pathological conditions. A causal role for interleukin-6 in the induction of fatigue and disruption of mitochondrial function has not been determined. What is the main finding and its importance? We demonstrate that chronically elevated interleukin-6 increased skeletal muscle fatigability and disrupted mitochondrial content and function independent of changes in fibre type and mass.

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This study provides the first comprehensive analysis of extracellular matrix protein (ECM) gene expression combined with echocardiographic analyses of heart functional parameters in the murine heart during pregnancy and the early postpartum period. Our findings show regulation of all Timp, selected Mmps, and Col1a1, Col3a1, and Col8a1 mRNA levels with reproductive status, with the greatest number of significant changes occurring in the early postpartum period. Left ventricle cardiac diastolic parameters were the first to change during pregnancy and remained elevated postpartum, whereas systolic parameters were increased in late pregnancy and began to recover during the first week postpartum.

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Objectives: To quantify the current bacteriology of deep surgical site infections (SSIs) after fracture surgery at 1 institution and to compare those data with historical controls at the same institution, assessing variations in infecting organisms over the past decade.

Design: Retrospective review.

Setting: Level I trauma center.

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Purpose Of Review: We highlight evidence for sexual dimorphism in preclinical and clinical studies investigating the cause and treatment of cancer cachexia.

Recent Findings: Cancer cachexia is unintended bodyweight loss occurring with cancer, and skeletal muscle wasting is a critical predictor of negative outcomes in the cancer patient. Skeletal muscle exhibits sexual dimorphism in fiber type, function, and regeneration capacity.

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Skeletal muscle has the dynamic capability to modulate protein turnover in response to anabolic stimuli, such as feeding and contraction. We propose that anabolic resistance, the suppressed ability to induce protein synthesis, is central to cancer-induced muscle wasting. Furthermore, we propose that resistance exercise training has the potential to attenuate or treat cancer-induced anabolic resistance through improvements in oxidative metabolism.

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Objectives: To identify the risk factors for early reoperation after operative fixation of acetabular fractures.

Design: Retrospective evaluation.

Setting: Level I Trauma Center.

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Objectives: To evaluate the incidence of unplanned reoperations after pelvic ring injuries and to develop a risk prediction model.

Design: Retrospective review.

Setting: Level I Trauma Center.

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Objectives: To evaluate the effectiveness of intraoperative vancomycin powder in prevention of surgical site infection and biofilm formation on implants in a contaminated animal fixation model.

Methods: We created a rabbit surgical model including fixation implants at a tibial surgical site seeded with methicillin-resistant Staphylococcus aureus. Our study cohort included 18 rabbits.

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Cancer cachexia, a wasting syndrome characterized by skeletal muscle depletion, contributes to increased patient morbidity and mortality. While the intricate balance between protein synthesis and breakdown regulates skeletal muscle mass, the suppression of basal protein synthesis may not account for the severe wasting induced by cancer. Therefore, recent research has shifted to the regulation of "anabolic resistance," which is the impaired ability of nutrition and exercise to stimulate protein synthesis.

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