HERON: Demonstrating a Novel Biological Platform for Small Satellite Missions

Long-duration deep space missions pose a significant health risk for both humans and their resident microorganisms. The GeneSat, PharmaSat and O/OREOS missions have previously explored biological questions regarding the effects of spaceflight on S. cerevisiase, B. subtilis, and E. coli. However, there currently exists both a knowledge and an accessibility gap in small satellite biological experiments. These payloads require precise instrumentation and complex platforms that are usually reserved for large research organizations. This makes it difficult for smaller organizations to perform biological research in low Earth orbit (LEO). To address these challenges, the University of Toronto Aerospace Team (UTAT) Space Systems Division is currently developing the HERON CubeSat. HERON houses a payload platform which measures the effects of the LEO environment on the gene expression and drug resistance of Candida albicans, a yeast commonly found in the human gut microbiome. Previous research has suggested that C. albicans might display increased pathogenicity and drug resistance in response to microgravity, which has important implications for long-duration human spaceflight. The yeast cells are housed in custom acrylic microfluidics chips containing 32 wells with channels for media and drug delivery. A measurement printed circuit board (PCB) contains custom optics capable of measuring minute changes in cell fluorescence. The entire payload stack is then housed in a temperature- and humidity-controlled 2U pressure vessel. Space Systems as a whole is an undergraduate student-led and student-funded design team, dedicated to the development of small satellite missions with a focus on education and undergraduate learning. HERON is scheduled to launch Q1 2022 into a Sun-synchronous orbit via a SpaceX Falcon 9 rocket at an altitude of approximately 550 km. Our platform is open-source and can serve as a low-cost template for future biological CubeSat missions. This paper serves as a technical and scientific description of the platform, along with the lessons learned during the payload design, assembly, and validation processes

Gastric cancer screening in common variable immunodeficiency

Individuals with common variable immunodeficiency (CVID) have an increased risk of gastric cancer, and gastrointestinal lymphoma, yet screening for premalignant gastric lesions is rarely offered routinely to these patients. Proposed screening protocols are not widely accepted and are based on gastric cancer risk factors that are not applicable to all CVID patients. Fifty-two CVID patients were recruited for screening gastroscopy irrespective of symptoms or blood results and were compared to 40 controls presenting for gastroscopy for other clinical indications. Overall, 34% of CVID patients had intestinal metaplasia (IM), atrophic gastritis or moderate to severe non-atrophic gastritis, which can increase the risk of gastric cancer, compared to 7.5% of controls (p < 0.01). Focal nodular lymphoid hyperplasia, a precursor lesion for gastrointestinal lymphoma, was seen in eight CVID patients (16%), one of whom was diagnosed with gastrointestinal lymphoma on the same endoscopy. High-risk gastric pathology was associated with increased time since diagnosis of CVID, smoking, Helicobacter pylori, a low-serum pepsinogen I concentration, and diarrhea, but not pepsinogen I/II ratio, iron studies, vitamin B12 levels or upper gastrointestinal symptoms. There was a lower rate of detection of IM when fewer biopsies were taken, and IM and gastric atrophy were rarely predicted by the endoscopist macroscopically, highlighting the need for standardized biopsy protocols. The prevalence of premalignant gastric lesions in patients with CVID highlights the need for routine gastric screening. We propose a novel gastric screening protocol to detect early premalignant lesions and reduce the risk of gastric cancer and gastric lymphoma in these patients