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In JoVE (1)
Other Publications (6)
Articles by Leslie A. Morton in JoVE
JoVE Bioengineering
Constant Pressure-controlled Extrusion Method for the Preparation of Nano-sized Lipid Vesicles
1Department of Chemistry & Biochemistry, University of Colorado Boulder, 2Biofrontiers Institute, University of Colorado Boulder
This protocol describes an extrusion method for preparing lipid vesicles of sub-micron sizes with a high degree of homogeneity. This method uses a pressure-controlled system with controlled nitrogen flow rates for liposome preparation. The lipid preparation1,2, liposome extrusion, and size characterization will be presented herein.
Other articles by Leslie A. Morton on PubMed
Aberrant Hypermethylation in Primary and Sentinel Lymph Node Metastases in Pediatric Cutaneous Melanoma Patients
Background: Debate on how to manage pediatric cutaneous melanoma patients continues; particularly in those with sentinel lymph node(SLN) metastases who are at higher risk of poor outcomes. Management is often based on adult algorithms, although differences in clinical outcomes between pediatric and adult patients suggests that melanoma in pediatric patients differs biologically. Yet, there are no molecular prognostic studies identifying these differences. Objectives: We investigated the epigenetic(methylation) regulation of several tumor-related genes(TRGs) known to be significant in adult melanoma progression in histopathology(+) SLN metastases(n=17) and primary tumors(n=20) of pediatric melanoma patients to determine their clinical relevance. Methods: AJCC Stage I-III(n=37) pediatric cutaneous melanoma patients(≤ 21 years at diagnosis) were analyzed. Gene promoter methylation of TRGs: RASSF1A, RARβ2, WIF1, and APC was evaluated. Results: Hypermethylation of RASSF1A, RARβ2, WIF1, and APC in histopathology(+) SLNs was 29.4%(5/17), 25%(4/16), 25%(4/16), and 18.8%(3/16), respectively. When matched to adult cutaneous melanomas by Breslow thickness and ulceration, hypermethylation of all four TRGs in SLN(+) pediatric melanoma patients was equivalent to or less than in adults. With a median follow-up of 55 months, SLN(+) pediatric melanoma patients with hypermethylation of >1 TRGs versus ≤1 TRG had worse disease-free(p=0.02) and overall survival(p=0.02). Conclusions: Differences in the methylation status of these TRGs in the SLN(+) pediatric and adult melanoma patients may account for why SLN(+) pediatric patients have different clinical outcomes. SLN biopsy should continue to be performed; within SLN(+) pediatric melanoma patients, hypermethylation of TRGs can be used to identify a subpopulation at highest risk for poor outcomes who warrant vigilant clinical follow-up.
Obesity is Associated with Hypothalamic Injury in Rodents and Humans
Rodent models of obesity induced by consuming high-fat diet (HFD) are characterized by inflammation both in peripheral tissues and in hypothalamic areas critical for energy homeostasis. Here we report that unlike inflammation in peripheral tissues, which develops as a consequence of obesity, hypothalamic inflammatory signaling was evident in both rats and mice within 1 to 3 days of HFD onset, prior to substantial weight gain. Furthermore, both reactive gliosis and markers suggestive of neuron injury were evident in the hypothalamic arcuate nucleus of rats and mice within the first week of HFD feeding. Although these responses temporarily subsided, suggesting that neuroprotective mechanisms may initially limit the damage, with continued HFD feeding, inflammation and gliosis returned permanently to the mediobasal hypothalamus. Consistent with these data in rodents, we found evidence of increased gliosis in the mediobasal hypothalamus of obese humans, as assessed by MRI. These findings collectively suggest that, in both humans and rodent models, obesity is associated with neuronal injury in a brain area crucial for body weight control.
Preclinical Characterization of a Novel Diphenyl Benzamide Selective ERα Agonist for Hormone Therapy in Prostate Cancer
Androgen deprivation therapy (ADT) is the mainstay of treatment for advanced prostate cancer. ADT improves overall and disease-free survival rates, but long-term therapy is associated with severe side effects of androgen and estrogen depletion including hot flashes, weight gain, depression, and osteoporosis. Effective hormone reduction can be achieved without estrogen deficiency-related side effects by using therapy with estrogenic compounds. However, cardiovascular complications induced by estrogens coupled with the availability of LHRH agonists led to discontinuation of estrogen use for primary androgen deprivation therapy in the 1980s. New treatments for prostate cancer that improve patient outcomes without the serious estrogen deficiency-related toxicities associated with ADT using LHRH analogs are needed. Herein we describe a novel nonsteroidal selective estrogen receptor-α agonist designed for first-line therapy of advanced prostate cancer that in animal models induces medical castration and minimizes many of the estrogen deficiency-related side effects of ADT. The present studies show that orally administered GTx-758 reversibly suppressed testosterone to castrate levels and subsequently reduced prostate volume and circulating prostate-specific antigen in relevant preclinical models without inducing hot flashes, bone loss, thrombophilia, hypercoagulation, or increasing fat mass.
Sequencing Chromosomal Abnormalities Reveals Neurodevelopmental Loci That Confer Risk Across Diagnostic Boundaries
Balanced chromosomal abnormalities (BCAs) represent a relatively untapped reservoir of single-gene disruptions in neurodevelopmental disorders (NDDs). We sequenced BCAs in patients with autism or related NDDs, revealing disruption of 33 loci in four general categories: (1) genes previously associated with abnormal neurodevelopment (e.g., AUTS2, FOXP1, and CDKL5), (2) single-gene contributors to microdeletion syndromes (MBD5, SATB2, EHMT1, and SNURF-SNRPN), (3) novel risk loci (e.g., CHD8, KIRREL3, and ZNF507), and (4) genes associated with later-onset psychiatric disorders (e.g., TCF4, ZNF804A, PDE10A, GRIN2B, and ANK3). We also discovered among neurodevelopmental cases a profoundly increased burden of copy-number variants from these 33 loci and a significant enrichment of polygenic risk alleles from genome-wide association studies of autism and schizophrenia. Our findings suggest a polygenic risk model of autism and reveal that some neurodevelopmental genes are sensitive to perturbation by multiple mutational mechanisms, leading to variable phenotypic outcomes that manifest at different life stages.
Imaging in the Management of Ischemic Cardiomyopathy: Special Focus on Magnetic Resonance
Heart failure of ischemic origin has become increasingly common over the last decade because of the improved survival of patients with acute myocardial infarction. Revascularization with coronary bypass grafting or percutaneous coronary intervention plays a pivotal role in patients with ischemic cardiomyopathy, although these interventions are often associated with relatively high peri-procedural risk. The pathophysiological substrate of ischemic cardiomyopathy is heterogeneous, varying from predominantly hibernating myocardium to irreversible scarring. There is evidence to suggest that patients with hibernating myocardium benefit most from revascularization, whereas medical therapy is associated with an adverse prognosis. Therefore, noninvasive testing is recommended by relevant guidelines to guide optimal management in these patients. However, the role of noninvasive testing has recently been challenged. There are various imaging modalities available that provide information on different aspects of the disease, and therefore, they differ significantly in sensitivity and specificity. In clinical practice, choosing among the different imaging modalities can be difficult. Cardiac magnetic resonance has evolved into a comprehensive modality that can accurately determine the amount of hibernating myocardium as well as the presence and degree of myocardial ischemia and the extent of the scar. This paper reviews the indications, accuracy, and clinical utility of the available imaging techniques, with a special focus on cardiac magnetic resonance in ischemic cardiomyopathy, and provides an outlook on how this field might evolve in the future.
Using Robotic Telecommunications to Triage Pediatric Disaster Victims
During a disaster, hospitals may be overwhelmed and have an insufficient number of pediatric specialists available to care for injured children. The aim of this study was to determine the feasibility of remotely providing pediatric expertise via a robot to treat pediatric victims.
