The effect of fatty infiltration, revision surgery, and sex on lumbar multifidus passive mechanical properties.

Purpose: Previous research has demonstrated increased stiffness in the multifidus muscle compared to other paraspinal muscles at the fiber bundle level. We aimed to compare single fiber and fiber bundle passive mechanical properties of multifidus muscle: (1) in 40 patients undergoing primary versus revision surgery and (2) in muscle with mild versus severe fatty infiltration. Methods: The degree of muscle fatty infiltration was graded using the patients' spine magnetic resonance images. Average single fiber and fiber bundle passive mechanical properties across three tests were compared between primary (N = 30) and revision (N = 10) surgery status, between mild and severe fatty infiltration levels, between sexes, and with age from passive stress-strain tests of excised multifidus muscle intraoperative biopsies. Results: At the single fiber level, elastic modulus was unaffected by degree of fatty infiltration or surgery status. Female sex (p = 0.001) and younger age (p = 0.04) were associated with lower multifidus fiber elastic modulus. At the fiber bundle level, which includes connective tissue around fibers, severe fatty infiltration (p = 0.01) and younger age (p = 0.06) were associated with lower elastic modulus. Primary surgery also demonstrated a moderate, but non-significant effect for lower elastic modulus (p = 0.10). Conclusions: Our results demonstrate that female sex is the primary driver for reduced single fiber elastic modulus of the multifidus, while severity of fatty infiltration is the primary driver for reduced elastic modulus at the level of the fiber bundle in individuals with lumbar spine pathology.

Multifunctional Antibacterial Nanonets Attenuate Inflammatory Responses through Selective Trapping of Endotoxins and Pro-Inflammatory Cytokines.

Extracellular lipopolysaccharide (LPS) released from bacteria cells can enter the bloodstream and cause septic complications with excessive host inflammatory responses. Target-specific strategies to inactivate inflammation mediators have largely failed to improve the prognosis of septic patients in clinical trials. By utilizing their high density of positive charges, de novo designed peptide nanonets are shown to selectively entrap the negatively charged LPS and pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). This in turn enables the nanonets to suppress LPS-induced cytokine production by murine macrophage cell line and rescue the antimicrobial activity of the last-resort antibiotic, colistin, from LPS binding. Using an acute lung injury model in mice, it is demonstrated that intratracheal administration of the fibrillating peptides is effective at lowering local release of TNF-α and IL-6. Together with previously shown ability to simultaneously trap and kill pathogenic bacteria, the peptide nanonets display remarkable potential as a holistic, multifunctional anti-infective, and anti-septic biomaterial.

Reduced Dose Computed Tomography: The Effects of Voltage Reduction on Density Measurements of Urolithiasis.

CT is a widely used imaging modality in the diagnosis of urolithiasis but subjects patients to ionizing radiation. Reduced dose protocols have recently gained wide acceptance. Stone density measurements have been used to predict composition and help guide treatment in standard dose CT (sCT) but not in reduced dose CT (RdCT). We aimed to compare density measurements obtained through RdCT vs sCT and to determine if there is a correlation between stone composition. A total of 201 patients undergoing evaluation for renal colic were prospectively recruited, whereby each subject underwent an sCT (120 kVp) followed immediately by an RdCT (80 or 100 kVp). All calculi <5 mm were excluded to prevent volume averaging and distortion to Hounsfield units measurements. The iliac bone cortex was utilized as an internal control. We also collected stone compositional analyses. In total 36 stones were identified. When the same calculi were evaluated with 120 kVp vs 80 kVp, the RdCT revealed a higher HU (n = 18, 1214 ± 520 vs 1007 ± 307, p < 0.005). Statistical difference was not achieved when 120 kVp was compared with 100 kVp scans (p = 0.151). The percentage differences were 10.6 ± 21 and 1.4 ± 15, respectively. Measurements of the iliac crest mirrored the findings of calculi, with density measurements in 80 kVp being statistically higher than those obtained through 120 kVp. A total of 41 stone analyses were reviewed in accordance with variable CT dosages. When stratified by CT kVp and stone composition, RdCTs trended toward wider density ranges than sCT. Density measurements of urolithiasis in RdCT, achieved by voltage reduction, corresponds to a paradoxical increase in HU. Although HU can be used as a predictor for stone composition, there can be a wide deviation in measured density, and this can be further magnified in the setting of dose reduction.

Predictors of radiation exposure to providers during percutaneous nephrolithotomy.

BACKGROUND: Limited studies have reported on radiation risks of increased ionizing radiation exposure to medical personnel in the urologic community. Fluoroscopy is readily used in many urologic surgical procedures. The aim of this study was to determine radiation exposure to all operating room personnel during percutaneous nephrolithotomy (PNL), commonly performed for large renal or complex stones. MATERIALS AND METHODS: We prospectively collected personnel exposure data for all PNL cases at two academic institutions. This was collected using the Instadose™ dosimeter and reported both continuously and categorically as high and low dose using a 10 mrem dose threshold, the approximate amount of radiation received from one single chest X-ray. Predictors of increased radiation exposure were determined using multivariate analysis. RESULTS: A total of 91 PNL cases in 66 patients were reviewed. Median surgery duration and fluoroscopy time were 142 (38-368) min and 263 (19-1809) sec, respectively. Median attending urologist, urology resident, anesthesia, and nurse radiation exposure per case was 4 (0-111), 4 (0-21), 0 (0-5), and 0 (0-5) mrem, respectively. On univariate analysis, stone area, partial or staghorn calculi, surgery duration, and fluoroscopy time were associated with high attending urologist and resident radiation exposure. Preexisting access that was utilized was negatively associated with resident radiation exposure. However, on multivariate analysis, only fluoroscopy duration remained significant for attending urologist radiation exposure. CONCLUSION: Increased stone burden, partial or staghorn calculi, surgery and fluoroscopy duration, and absence of preexisting access were associated with high provider radiation exposure. Radiation safety awareness is essential to minimize exposure and to protect the patient and all providers from potential radiation injury.

Lumbar spine postures in Marines during simulated operational positions.

Low back pain has a 70% higher prevalence in members of the armed forces than in the general population, possibly due to the loads and positions soldiers experience during training and combat. Although the influence of heavy load carriage on standing lumbar spine posture in this population is known, postures in other operationally relevant positions are unknown. Therefore, the purpose of this study was to characterize the effect of simulated military operational positions under relevant loading conditions on global and local lumbar spine postures in active duty male US Marines. Secondary objectives were to evaluate if intervertebral disc degeneration and low back pain affect lumbar spine postures. Magnetic resonance images were acquired on an upright scanner in the following operational positions: Natural standing with no external load, standing with body armor (11.3 kg), sitting with body armor, and prone on elbows with body armor. Custom software was used to measure global lumbar spine posture: Lumbosacral flexion, sacral slope, lordosis, local measures of intervertebral angles, and intervertebral distances. Sitting resulted in decreased lumbar lordosis at all levels of the spine except L1-L2. When subjects were prone on elbows, a significant increase in local lordosis was observed only at L5-S1 compared with all other positions. Marines with disc degeneration (77%) or history of low back pain (72%) had decreased lumbar range of motion and less lumbar extension than healthy Marines. These results indicate that a male Marine's pathology undergoes a stereotypic set of postural changes during functional tasks, which may impair performance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2145-2153, 2017.

The Association of Erectile Dysfunction and Cardiovascular Disease: A Systematic Critical Review.

Despite strong association between erectile dysfunction (ED) and cardiovascular disease (CVD), there is a paucity of clear clinical guidelines detailing when and how to evaluate for ED in patients with known CVD, or vice versa. This systematic review discuss the role of cardiologists and urologists in the characterization of risk and management of CVD in the setting of ED, as well as contrasting the current evaluation of CVD and ED from the standpoint of published consensus statements. A comprehensive literature review utilizing MEDLINE®, the Cochrane Library® Central Search, and the Web of Science was performed to identify all published peer-reviewed articles in the English language describing ED and CVD across various disciplines. There is strong consensus that men with ED should be considered at high risk of CVD. Available risk assessment tools should be used to stratify the coronary risk score in each patient. The 2012 Princeton III Consensus Conference expanded on existing cardiovascular recommendations, proposing an approach to the evaluation and management of cardiovascular risk in men with ED and no known CVD. This systematic review highlights the similarities and differences of the existing clinical guidelines and recommendations regarding assessment and management of ED and CVD, as well as the pathophysiological linkage between ED and CVD, which may permit physicians, including urologists, to perform opportunistic screening and initiate secondary prophylaxis with regard to cardiovascular risk factors, particularly in young, nondiabetic men with ED.

Treatment of a giant congenital melanocytic nevus in the adult: review of the current management of giant congenital melanocytic nevus.

Giant congenital melanocytic nevi (GCMNs) create cosmetic disfigurements and pose risk for malignant transformation. Adult GCMN cases are uncommon because most families opt for surgical treatment during childhood. We review the current literature on GCMN and present an interesting case of an adult with a GCMN encompassing the entire back with painful nodules exhibiting gross involvement of his back musculature, without pathologic evidence of malignancy. Surgical management was deferred in childhood because of parental desires to allow the patient to make his own decision, and treatment in adulthood was pursued on the basis of the significant impairment of the patient's quality of life and self-esteem due to the massive size and deforming nature of the nevus. The treatment strategy used for this young adult male patient involved a massive en bloc excision of the GCMN with partial resection of the latissimus dorsi, followed by a 5-week staged reconstructive process using dermal regenerative matrices and split-thickness skin grafting. Because of the shift in GCMN management from early surgical management to more conservative management, we may see an increase in adult cases of GCMN. Thus, it is critical to better understand the controversy surrounding early versus delayed management of GCMN.

The effect of testosterone on cardiovascular disease: a critical review of the literature.

Cardiovascular disease is the leading cause of death in the United States. Testosterone is the principal male sex hormone and plays an important role in men's health and well-being. Historically, testosterone was believed to adversely affect cardiovascular function. However, contemporary literature has refuted this traditional thinking; testosterone has been suggested to have a protective effect on cardiovascular function through its effects on the vascular system. Data from modern research indicate that hypogonadism is closely related to the development of various cardiovascular risk factors, including hyperlipidemia and insulin resistance. Several studies have demonstrated beneficial effects of testosterone supplementation therapy on reversing symptoms of hypogonadism and improving cardiovascular disease risk profiles. In this review, we perform a critical analysis on the association between testosterone and cardiovascular disease.