Clinical Research Directory

The Role of Estrogen and Testosterone in Determining Brain Blood Flow and Metabolic Regulation in Humans

Due to historical exclusion of females from research, there are gaps in the understanding of female physiology, how it differs from males, and how sex-specific hormones contribute. As a result, many diagnoses and treatments are based on male physiology and may not be appropriate or effective for females. Females consistently experience greater risk and report worse neurological outcomes in many diseases, including stroke, cardiac arrest, and dementia. As research in females progresses, differences between sexes and changes throughout the lifespan (e.g., puberty, menopause) highlight the importance of understanding the effects of sex and sex-specific hormones on the body. The brain is arguably the most important organ in the body, consuming 20% of the body's total energy. Previous research supports higher blood flow to the brain in females, and research in animals suggests hormones such as estrogen, progesterone, and testosterone are responsible. However, it is extremely difficult to isolate these hormones in humans, due to natural fluctuations (i.e., menstrual cycle). Therefore, the investigators plan to explore the direct role of these sex-specific hormones in regulating blood flow to the brain by blocking hormone production in healthy males and females and giving back testosterone and estrogen, respectively. The investigators will then conduct a range of tests to look at blood flow to the brain at rest and during various stressors. This research will provide crucial insight into how males and females differ in regulation of brain blood flow and inform new treatments and therapies to a wide range of brain injuries and diseases, improving outcomes and reducing the sex disparity in clinical pathways.

The PASTDUe Nutrition Ecosystem Project (PASTDUe)

This is a research study to determine if a particular method of providing nutrition improves the clinical outcomes of patients in the intensive care unit (ICU) who have undergone abdominal surgery and would require nutrition delivered via the bloodstream (called total parenteral nutrition or TPN). The nutrition method we are testing is a structured nutrition delivery plan that involves tube feeding, oral nutrition supplements, and the use of a device (called an indirect calorimeter or IC) to measure calorie needs. This study will also use two devices to measure fat and muscle mass to examine changes during hospitalization. Subjects will be followed throughout hospitalization where nutrition status and fat and muscle mass will be closely monitored. Study activities will begin within 72 hours of a patient's abdominal surgery. TPN (total parenteral nutrition, a method of feeding that bypasses the usual process of eating and digestion) will be started, a non-invasive method of assessing calorie needs (indirect calorimetry (IC)) will be started, a urine sample will be collected to help assist in protein needs, and fat/muscle mass will be measured using bioelectrical impedance analysis (BIA), and an ultrasound. This is a minimal risk study and all products/devices used are non-invasive and FDA-approved. Indirect calorimetry and urine sample collection will be conducted every 3 days during the stay in the Intensive Care Unit - ICU, then every 5 days until hospital discharge. BIA and muscle ultrasound will be conducted every 7 days during ICU stay, then every 14 days until hospital discharge.

NON-INVASIVE BLOOD FLOW ASSESSMENT: Computational Tool for Measuring Arterial Flow From CT

Major invasive surgery, such as oncological abdominal surgery, is associated with a high risk of complications and mortality. One of the main problems in this type of surgery is the difficulty in preserving the arteries and veins necessary to support vital organs. The main objective of this project is to develop software to predict vascular flow changes based on preoperative computed tomography (CT) scans. Currently, the only way to assess preoperative vascular flow is through percutaneous angiography. This is an invasive procedure that requires anaesthesia, hospitalisation, high doses of radiation, vessel manipulation and the possibility of serious injury. It is often used for the diagnosis of vascular stenosis, analysis of vascular flow and preoperative planning to determine which vessels are directly related to organ perfusion. This preoperative planning will be key in the following clinical scenarios: 1. Anomalous hepatic artery anatomy in pancreaticoduodenectomy. 2. Celiac trunk stenosis. 3. Hepatic artery revascularisation from the superior mesenteric artery. 4. Hepatic artery flow assessment in liver transplantation. 5. Splenic artery flow steal phenomenon in liver transplantation. Novella aims to develop a tool that has the capability to predict postoperative vascular flow.