Extended duration orbiter medical project Microbial Air Sampler (STS-50/USML-1)

The Microbial Air Sampler was used on mission days 1, 7, and 13 in the Spacelab during STS-50/USML-1. Microbial air samples were collected using two types of media strips containing agar (Rose Bengal for yeast and molds, TSA for bacteria). The bacterial level found on day 1 was lower than experienced on previous Spacelab missions. A high level of fungi was present on day 1, however subsequent samples on days 7 and 13 did not indicate fungal growth. Bacterial growth was also minimized in this microgravity environment as the mission progressed. No pathogenic microorganisms were isolated, and the health risk from airborne microbes was minimal throughout the mission

Extended duration orbiter medical project countermeasure to reduce post space flight orthostatic intolerance (LBNP) (STS-50/USML-1)

During the STS-50/USML-1 mission and five other Shuttle flights, decompression of the legs and lower abdomen ('lower body negative pressure,' LBNP) was used: (1) to apply a standardized stress to the cardiovascular system, to document the loss of orthostatic function during an extended period in weightlessness, and (2) to test its efficacy as a treatment which may be used to protect astronauts from gravitationally-induced fainting during and after reentry on Space Shuttle flights. The loss of orthostatic tolerance (as determined by LBNP) occured even earlier than indicated by similar testing on Skylab (1973-1974). The treatment was shown to be effective in reversing some of the effects of extended weightlessness on the cardiovascular system for at least one day after treatment

Extended duration orbiter medical project variability of blood pressure and heart rate (STS-50/USML-1)

Decreases in arterial baroreflex function after space flight may be related to changes in blood pressure and heart rate patterns during flight. Ambulatory blood pressure and heart rate were measured for 24 hours, in fourteen astronauts on two occasions before flight, two to three occasions in flight, and 2 days after landing on Shuttle missions lasting 4 to 14 days. Blood pressure and heart rate were recorded every 20minutes during awake periods and every 30 minutes during sleep. In pre- and postflight studies, the 24-hour ambulatory measurements were followed by studies of carotid baroreceptor-cardiac reflex responses. Carotid baroreceptors were stimulated using a sequence of neck pressure and suction from +40 to -65 mmHg

Influence of gold nanoparticles on collagen fibril morphology quantified using transmission electron microscopy and image analysis

BACKGROUND: Development of implantable biosensors for disease detection is challenging because of poor biocompatibility of synthetic materials. A possible solution involves engineering interface materials that promote selfassembly and adhesion of autologous cells on sensor surfaces. Crosslinked type-I collagen is an acceptable material for developing engineered basement membranes. In this study, we used functionalized gold nanoparticles as the crosslinking agent. Functionalized nanoparticles provide sites for crosslinking collagen as well as sites to deliver signaling compounds that direct selfassembly and reduce inflammation. The goal of this study was to obtain a quantitative parameter to objectively determine the presence of crosslinks. METHODS: We analyzed TEM images of collagen fibrils by two methods: Run length analysis and topology analysis after medial axis transform. RESULTS: Run length analysis showed a significant reduction of the interfibril spaces in the presence of nanoparticles (change of 40%, P < 0.05), whereas the fibril thickness remained unchanged. In the topological network, the number of elements, number of branches and number of sides increased significantly in the presence of nanoparticles (P < 0.05). Other parameters, especially the number of loops showed only a minimal and nonsignificant change. We chose a ratiometric parameter of the number of branches normalized by the number of loops to achieve independence from gross fibril density. This parameter is lower by a factor of 2.8 in the presence of nanoparticles (P < 0.05). CONCLUSION: The numerical parameters presented herein allow not only to quantify fibril mesh complexity and crosslinking, but also to help quantitatively compare cell growth and adhesion on collagen matrices of different degree of crosslinking in further studies