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Todd, P.

Publications and source records attributed to Todd, P..

32 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Morphology of human embryonic kidney cells in culture after space flight

The ability of human embyronic kidney cells to differentiate into small epithelioid, large epithelioid, domed, and fenestrated morphological cell types following space flight is examined. Kidney cells exposed to 1 day at 1 g, then 1 day in orbit, and a 12 minute passage through the electrophoretic separator are compared with control cultures. The data reveal that 70 percent of small epithelioid, 16 percent of large epithelioid, 9 percent of dome-forming, and 5 percent of fenestrated cells formed in the space exposed cells; the distributions correlate well with control data. The formation of domed cells from cells cultured from low electrophoretic mobility fractions and small epithelioid cells from high mobility fractions is unaffected by space flight conditions. It is concluded that storage under microgravity conditions does not influence the morphological differentiation of human embryonic kidney cells in low-passage culture.

Todd, P.↗
NASA NTRS1985

Purification and Cultivation of Human Pituitary Growth Hormones Secreting Cells

The rat and human pituitary gland contains a mixture of hormone producing cell types. The separation of cells which make growth hormone (GH) is attempted for the purpose of understanding how the hormone molecule is made within the pituitary cell; what form(s) it takes within the cell; and what form(s) GH assumes as it leaves the cell. Since GH has a number of biological targets (e.g., muscle, liver, bone), the assessment of the activities of the intracellular/extracellular GH by new and sensitive bioassays. GH cells contained in the mixture was separated by free flow electrophoresis. These experiments show that GH cells have different electrophoretic mobilities. This is relevant to NASA since a lack of GH could be a prime causative factor in muscle atrophy. Further, GH has recently been implicated in the etiology of motion sickness in space. Continous flow electrophoresis experiment on STS-8 showed that GH cells could be partially separated in microgravity. However, definitive cell culture studies could not be done due to insufficient cell recoveries.

Hymer, W. C.↗
NASA NTRS1985

Kidney Cell Electrophoresis

Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated, ground support in the form of analytical cell electrophoresis and flow cytometry was provided and cells returned from space flight were analyzed. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. The protocol established and utilized is given.

Todd, P.↗
NASA NTRS1983

Electrophoretic purification of cells in space - Evaluation of results from STS-3

The procedure and results of Electrophoresis Equipment Verification Test, designed to examine electrophoretic behavior of animal cells is suspension more concentrated than possible on earth and flown on the Shuttle flight STS-3, were discussed. Ground-based laboratory values of electrophoretic mobilities of a mixture of human and rabbit aldehyde-fixed red blood cells (RBC) were compared with those recorded at 11 minute intervals on the Shuttle STS-3. RBC migration and separation observed through photographic records were not as expected. However, cell mobilities and migrating band profiles were consistent with the results of laboratory simulation experiments. It was concluded that zero G electrophoresis of very high concentrations (1 x 10 to the 9th) is possible and similar to electrophoresis of normal cell concentrations on earth.

Sarnoff, B. E.↗
NASA NTRS1980

Kidney cell electrophoresis

The following aspects of kidney cell electrophoresis are discussed: (1) the development and testing of electrophoresis solutions; (2) optimization of freezing and thawing; (3) procedures for evaluation of separated kidney cells; and (4) electrophoretic mobility characterization of kidney cells.

Todd, P.↗
NASA NTRS1979

Kidney cell electrophoresis

A kidney cell electrophoresis technique is described in four parts: (1) the development and testing of electrophoresis solutions; (2) optimization of freezing and thawing; (3) procedures for evaluation of separated kidney cells; and (4) electrophoretic mobility characteristics of kidney cells.

Todd, P.↗
NASA NTRS1977

Gravity and the cell: Intracellular structures and Stokes sedimentation

Plant and certain animal embryos appear to be responsive to the gravity vector during early stages of development. The convection of particle sedimentation as the basis for the sensing of gravity is investigated using the cells of wheat seedlings, amphibian embryos, and mammals. Exploration of the mammalian cell for sedimenting particles reveals that their existence is unlikely, especially in the presence of a network of microtubules and microfilaments considered to be responsible for intracellular organization. Destruction of these structures renders the cell susceptible to accelerations several times g. Large dense particles, such as chromosomes, nucleoli, and cytoplasmic organelles are acted upon by forces much larger than that due to gravity, and their positions in the cell appear to be insensitive to gravity.

Todd, P.↗