Publications by authors named "Trevor Hamilton"

Conditioned preference paradigms like conditioned colour preference tests (CCP) can be used to investigate addictive drug seeking in zebrafish (Danio rerio), but many aspects of this procedure require further study. Conditioned preference can be tested with either biased or unbiased conditioning methods, each with their own strengths and weaknesses. The present study used unbiased stimuli to test seeking behaviour in ethanol-exposed zebrafish at different durations of drug withdrawal.

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Article Synopsis
  • Gastrointestinal stromal tumors (GISTs) are tumors that come from specific cells in the gut and are primarily caused by certain genetic mutations; surgical removal is the best option for localized cases, while targeted drug therapies are the standard for management.
  • Recent advances in understanding GISTs have led to updates in treatment strategies, but disparities in care exist across Canada due to its provincial healthcare system, highlighting the need for standardized guidelines.
  • A panel of 20 experienced Canadian physicians from various specialties reviewed literature on GISTs to create a consensus on management practices, covering key topics like molecular profiling and multidisciplinary care to improve consistency in treatment across the country.
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Background: Patients with thick cutaneous pT4 malignant melanoma are at high risk for metastatic disease, and optimal staging is poorly defined. This study examines the frequency and modality of pre-operative staging to provoke thought on optimal staging.

Methods: A retrospective study was performed of patients with clinical T4N0 melanoma diagnosed between 2015-2017.

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This study investigated the effects of anxiogenic and anxiolytic drugs on zebrafish (Danio rerio) behaviour using a modified novel tank dive test with higher walls and a narrower depth. Zebrafish were administered chondroitin sulfate, beta-carboline, delta-9-tetrahydrocannabinol (THC), ethanol, and beta-caryophyllene, and their behaviours were evaluated for geotaxis, swimming velocity, and immobility. Both anxiogenic and anxiolytic compounds generally increased bottom-dwelling behaviour, suggesting that the tank's modified dimensions significantly influence zebrafish responses.

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Background: Surgical site infections (SSIs) are a common cause of morbidity after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal malignancy. Negative pressure wound therapy (NPWT) has been proposed as a method to reduce the rates of SSIs; however, there is paucity in the literature on the efficacy in this population. The goal of this study was to determine whether routine use of NPWT in patients undergoing CRS/HIPEC could reduce the risk of developing SSI.

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The therapeutic use of lysergic acid diethylamide (LSD) has resurfaced in the last decade, prompting further scientific investigation into its effectiveness in many animal models. Zebrafish (Danio rerio) are a popular model organism in medical sciences and are used to examine the repeated administration of pharmacological compounds. Previous zebrafish research found acute LSD altered behaviour and cortisol levels at high (250 µg/L) but not low (5-100 µg/L) levels.

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The β-Carboline FG-7142 is a partial inverse agonist at the benzodiazepine allosteric site on the GABA-A receptor that induces anxiogenic, proconvulsant, and appetite-reducing effects in many species, including humans. Seizure-kindling effects have been well studied, however anxiogenic properties are relatively unexplored. This study aimed to investigate concentration-dependent effects of FG-7142 on anxiety-like behaviour and fear responses in zebrafish (Danio rerio) using the open-field test (OF) and novel object approach test (NOA).

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Importance: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma. Due to its relatively low incidence and limited prospective trials, current recommendations are guided by historical single-institution retrospective studies.

Objective: To evaluate the overall survival (OS) of patients in Canada with head and neck MCC (HNMCC) according to American Joint Committee on Cancer 8th edition staging and treatment modalities.

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Terpenes are the most extensive and varied group of naturally occurring compounds mostly found in plants, including cannabis, and have an array of potential therapeutic benefits for pathological conditions. The endocannabinoid system can potently modulate anxiety in humans, rodents, and zebrafish. The 'entourage effect' suggests terpenes may target cannabinoid CB and CB receptors, among others, but this requires further investigation.

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Innate (natural) colour preference in animals is used for a variety of behavioural neuroscience purposes in many animal models. In zebrafish, colour preference is often used in combination with place preference testing and some memory tests. However, baseline colour preference seems to differ in the few studies examining this innate behaviour.

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Introduction: Peritoneal mesothelioma (PM) is a rare malignancy originating from the peritoneal lining. Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) is the standard-of-care for patients with isolated PM. Due to a paucity of prospective data there are several different HIPEC protocols.

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We investigated whether CO-induced ocean acidification (OA) affects dopamine receptor-dependent behavior in bicolor damselfish (Stegastes partitus). Damselfish were kept in aquaria receiving flow through control (pH ~ 8.03; pCO ~ 384 μatm) or OA (pH ~ 7.

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Background: The objective of this study is to identify predictors for recurrent appendicitis in patients with appendicitis previously treated nonoperatively.

Methods: This is a prospective cohort study of all adult patients with appendicitis treated at a tertiary care hospital. Patient demographics, radiographic information, management, and clinical outcomes were recorded.

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This study assessed the sensitivity of four anxiety-like behaviour paradigms in zebrafish: the novel tank dive test, shoaling test, light/dark test, and the less common shoal with novel object test. A second goal was to measure the extent to which the main effect measures are related to locomotor behaviours to determine whether swimming velocity and freezing (immobility) are indicative of anxiety-like behaviour. Using the well-established anxiolytic, chlordiazepoxide, we found the novel tank dive to be most sensitive followed by the shoaling test.

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We have previously hypothesized that well-differentiated papillary mesothelial tumor (WDPMT) consists of 2 morphologically identical lesions, one of which is true WDPMT, while the other is a form of mesothelioma in situ. Here, we report 8 examples of the latter phenomenon, 3 with pleural disease (2 men/1 woman, ages 66 to 78 y); and 5 with peritoneal disease (all women, ages 31 to 81 y). At presentation the pleural cases all had effusions but no evidence of pleural tumor on imaging.

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Aquatic species are capable of detecting infrasound (sub-20 Hz frequencies) which may be a source of anthropogenic pollution and have a detrimental impact on the environmental fitness of fish. Infrasound is generated by infrastructure, producing acoustic frequency peaks that are not discernible by humans. The presence of these frequencies may therefore impact the environmental wellbeing of aquatic laboratory animals, which are often housed in spaces adjacent to facilities producing infrasound.

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Introduction: Endoscopic resection (ER) of early gastric cancer (EGC) is increasingly used in Eastern countries due to their low rates of lymph node metastasis (LNM); however, there is a paucity of evidence in Western countries. We investigated LNM and its effect on overall survival (OS) in Western patients with EGC.

Methods: Patients diagnosed with T1 gastric cancer between 2000 and 2017 were retrospectively evaluated.

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We know little about how - or even if in some species - fish shoal in darkness. We hypothesized that 'dark shoaling' occurs in zebrafish and therefore must depend upon lateral line sensory input. Shoaling in groups of five adult zebrafish was analyzed with motion tracking software.

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Terpenes possess a wide range of medicinal properties and are potential therapeutics for a variety of pathological conditions. This study investigated the acute effects of two cannabis terpenes, β-caryophyllene and α-pinene, on zebrafish locomotion, anxiety-like, and boldness behaviour using the open field exploration and novel object approach tests. β-caryophyllene was administered in 0.

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Introduction: Positive pathologic margins following gastric cancer (GC) resection carries a poor prognosis. We evaluated intraoperative frozen section (IFS) analysis of resection margins (RMs) as a quality indicator in GC surgery.

Methods: Patients referred to a provincial cancer agency with surgically resected non-metastatic GC between 2004 and 2012 were included.

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In East Asia, the role of lymph node (LN) mapping in assisting surgical lymphadenectomy, which is integral to the management of gastric cancer, has been explored. We sought to evaluate its safety and utility in Western patients. Thirteen patients with nonmetastatic gastric adenocarcinoma received endoscopic, peritumoural, submucosal indocyanine green fluorescence (ICG) injections before surgery, and ICG was assessed intraoperatively using a laparoscopic detection system.

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Background: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for peritoneal malignancies carries considerable morbidity; however, the significance of postoperative small bowel obstruction (SBO) is not well defined. We aim to identify predictors for post-CRS/HIPEC SBO and their oncologic associations.

Methods: A retrospective review was conducted of all CRS/HIPEC cases performed at a surgical oncology center (2013-2018).

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Background: Patients with malignancy often require urgent surgical consultation for treatment or palliation of disease. The objective of this study is to explore the prognostic determinants affecting care in acute cancer-related surgical presentations and the effect on patient outcomes.

Main Body: This is a retrospective review of patients referred to the acute general surgery (ACS) service at a tertiary hospital for management of cancer-related problem from July 2017 to September 2018.

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Background: Sentinel lymph node biopsy (SLNB) for melanoma plays a central role in determining prognosis and guiding treatment and surveillance strategies. Despite widely published guidelines for SLNB, variation exists in its use. We aimed to determine the frequency of and predictive factors for SLNB in patients with clinically node-negative melanoma in British Columbia.

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