Publications by authors named "Drummond G"

Global obesity rates have risen dramatically, now exceeding deaths from starvation. Metabolic and bariatric surgery (MBS), initially for severe obesity (BMI ≥35 kg/m), is performed globally over 500 000 times annually, offering significant metabolic benefits beyond weight loss. However, varying eligibility criteria globally impact patient care and healthcare resources.

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Astrocytes, which are increasingly recognized as pivotal constituents of brain circuits governing a wide range of functions, express GABA transporter 3 (Gat3), an astrocyte-specific GABA transporter responsible for maintenance of extra-synaptic GABA levels. Here, we examined the functional role of Gat3 in astrocyte-mediated modulation of neuronal activity and information encoding. First, we developed a multiplexed CRISPR construct applicable for effective genetic ablation of Gat3 in the visual cortex of adult mice.

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Updating behavior based on feedback from the environment is a crucial means by which organisms learn and develop optimal behavioral strategies. Norepinephrine (NE) release from the locus coeruleus (LC) has been shown to mediate learned behaviors such that in a task with graded stimulus uncertainty and performance, a high level of NE released after an unexpected outcome causes improvement in subsequent behavior. Yet, how the transient activity of LC-NE neurons, lasting tens of milliseconds, influences behavior several seconds later, is unclear.

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The brainstem region, locus coeruleus (LC), has been remarkably conserved across vertebrates. Evolution has woven the LC into wide-ranging neural circuits that influence functions as broad as autonomic systems, the stress response, nociception, sleep, and high-level cognition among others. Given this conservation, there is a strong possibility that LC activity is inherently similar across species, and furthermore that age, sex, and brain state influence LC activity similarly across species.

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Background: The impact of preoperative weight loss on long-term weight loss outcomes and comorbidity resolution in both laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB) are poorly reported. Understanding this relationship is necessary to guide surgeons toward appropriate procedure and patient selection. The present study investigates long-term weight loss outcomes and comorbidity resolution following LSG and LRYGB and investigates the effect of preoperative variables on long-term outcomes.

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  • Astrophyses are crucial for memory processes and learning, with their activity linked to synaptic function and cognitive abilities, while other glial cells like microglia and oligodendrocytes also play significant roles in shaping these processes.
  • Recent technological advancements have improved our understanding of glial functions, highlighting the need for more research on neuron-glia interactions and their implications for brain health and neurological diseases.
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Pallamolide A is a 7,8--labdane terpenoid possessing a unique bicyclo[2.2.2]octane core and a spiro-butenolide moiety.

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  • Extra-embryonic yolk sac is identified as the origin of macrophages and endothelial cells found in adult mouse tissues.
  • Researchers have discovered clonogenic endothelial-macrophage (EndoMac) progenitor cells in the aorta that are not reliant on bone marrow and originate from early embryonic sources.
  • Angiotensin II plays a crucial role in enhancing the growth and differentiation of these EndoMac progenitors, which contribute to blood vessel formation and neovascularization in ischemic tissues.
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Introduction: Weight loss following bariatric surgery is variable and predicting inadequate weight loss is required to help select patients for bariatric surgery. The aim of the present study was to determine variables associated with inadequate weight loss and to derive and validate a predictive model.

Methods: All patients who underwent laparoscopic sleeve gastrectomy and Roux-en-Y gastrectomy (2008-2022) in a tertiary referral centre were followed up prospectively.

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Metabolic syndrome (MetS) is a cluster of metabolic abnormalities affecting ~25% of adults and is linked to chronic diseases such as cardiovascular disease, cancer, and neurodegenerative diseases. Oxidative stress and inflammation are key drivers of MetS. Hesperidin, a citrus bioflavonoid, has demonstrated antioxidant and anti-inflammatory properties; however, its effects on MetS are not fully established.

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  • Hypertension is a significant risk factor for both stroke and cognitive decline, but its specific impact on cognitive impairment after a stroke is still uncertain.
  • In a study with C57BL/6J mice, researchers induced hypertension and then conducted strokes to assess cognitive outcomes using the Barnes maze and analyzed the brain's transcriptomic profile through RNA sequencing.
  • Results indicated that hypertensive mice experienced worse cognitive performance and more brain injury compared to normotensive mice after a stroke, with over 1500 genes linked to neuroinflammation being differentially expressed.
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Introduction: Marginal zone and follicular B cells are known to contribute to the development of angiotensin II-induced hypertension in mice, but the effector function(s) mediating this effect (e.g., antigen presentation, antibody secretion and/or cytokine production) are unknown.

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Single-cell technologies such as flow cytometry and single-cell RNA sequencing have allowed for comprehensive characterization of the kidney cellulome. However, there is a disparity in the various protocols for preparing kidney single-cell suspensions. We aimed to address this limitation by characterizing kidney cellular heterogeneity using three previously published single-cell preparation protocols.

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Introduction: Outcomes of long-term (5-10-year) weight loss have not been investigated thoroughly and the role of pre-operative weight loss on long-term weight loss, among other factors, are unknown. Our regional bariatric service introduced a 12 week intensive pre-operative information course (IPIC) to optimise pre-operative weight loss and provide education prior to bariatric surgery. The present study determines the effect of pre-operative weight loss and an intense pre-operative information course (IPIC), on long-term weight outcomes and sustained weight loss post-bariatric surgery.

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  • The study investigates how angiotensin II treatment affects the gut microbiome using a large cohort of 303 male and female mice, addressing the limitations of previous smaller studies.
  • The analysis revealed that angiotensin II significantly influenced the diversity and composition of the microbiome, but other factors like diet, age, and sampling site had a much greater impact.
  • The findings highlight the importance of considering various experimental factors when studying microbiome changes related to hypertension, as angiotensin II's effects were modest compared to these factors.
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Aortic diseases such as atherosclerosis, aortic aneurysms, and aortic stiffening are significant complications that can have significant impact on end-stage cardiovascular disease. With limited pharmacological therapeutic strategies that target the structural changes in the aorta, surgical intervention remains the only option for some patients with these diseases. Although there have been significant contributions to our understanding of the cellular architecture of the diseased aorta, particularly in the context of atherosclerosis, furthering our insight into the cellular drivers of disease is required.

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  • Vascular inflammation and fibrosis are key issues in hypertension that can lead to heart disease and cognitive decline, but current treatments focus more on symptoms than underlying tissue damage.
  • A study on male mice showed that angiotensin II increased blood pressure and vascular damage, while injected amnion epithelial cells reduced these harmful effects and helped prevent cognitive impairment.
  • These results indicate that amnion epithelial cells may be a promising new therapy for addressing both vascular issues and cognitive decline in people with hypertension.
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Hypertension is a global health problem, with >1.3 billion individuals with high blood pressure worldwide. In this Review, we present an inflammatory paradigm for hypertension, emphasizing the crucial roles of immune cells, cytokines and chemokines in disease initiation and progression.

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Obesity and vascular dysfunction are independent and sexually dimorphic risk factors for cardiovascular disease. A high fat diet (HFD) is often used to model obesity in mice, but the sex-specific effects of this diet on aortic inflammation and function are unclear. Therefore, we characterized the aortic immune cell profile and function in 6-week-old male and female C57BL/6 mice fed a normal chow diet (NCD) or HFD for 10 weeks.

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In cardiovascular disease, pathological and protective roles are reported for the Th2 cytokines IL-4 and IL-13, respectively. We hypothesised that differential effects on macrophage function are responsible. Type I and II receptor subunit (IL-2Rγ, IL-4Rα and IL-13Rα1) and M2 marker (MRC-1, CCL18, CCL22) expression was assessed via RT-qPCR in IL-4- and IL-13-treated human primary macrophages.

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Intraepithelial lymphocytes (IELs), including αβ and γδ T cells (T-IELs), constantly survey and play a critical role in maintaining the gastrointestinal epithelium. We show that cytotoxic molecules important for defense against cancer were highly expressed by T-IELs in the small intestine. In contrast, abundance of colonic T-IELs was dependent on the microbiome and displayed higher expression of TCF-1/ and a reduced effector and cytotoxic profile, including low expression of granzymes.

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Intermittent fasting (IF) has been shown to reduce cardiovascular risk factors in both animals and humans, and can protect the heart against ischemic injury in models of myocardial infarction. However, the underlying molecular mechanisms behind these effects remain unclear. To shed light on the molecular and cellular adaptations of the heart to IF, we conducted comprehensive system-wide analyses of the proteome, phosphoproteome, and transcriptome, followed by functional analysis.

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