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Changing gravity and weightlessness effects on vasopressin control systems, with immunochemical and biological assay studies
Statistical procedures for investigating decontamination of spacecraft and microbial assays
Assay procedures for extraction and determination of N-acetylglucosamine in soil
Instrument assays enzymatic bioluminescent reaction that occurs when adenosine triphosphate /ATP/ combines with lucifrase and luciferin. Module assembly minimizes need for hardware associated with reaction fluid and waste transfer. System is applicable in marine biology and aerospace and medical fields.
Assays of hormonal control of calcium and bone metabolism
Radioimmunochemical assay for ACTH levels in human plasma hormones
The solubility and/or swelling of cured epoxy resins was studied using the solubility parameter method. Determination of solubility parameters were found in order to select solvents for solvent-assisted degradation of cured epoxy polymers used in spacecraft. A method for improving recovery of seeded spores is suggested for assay of buried contaminants. Three commercial epoxy resins were cured using four different alkyl amines. For each resin-amine combination, three levels of amine were used, corresponding to 1/3, 2/3, and all of the amine required to react with the oxirane groups of the resin. The solubility parameters of the 36 resulting model compounds were determined in poorly and moderately hydrogen-bonded solvents. No strongly hydrogen-bonded solvents caused dissolution or swelling. The tolerance of cured resins is discussed in terms of polymer structure.
An immunoassay to determine the effects of changing gravity and weightlessness on vasopressin control system is discussed. Seven extracts from persons known to have inappropriate ADH syndrome secondary to pulmonary oat cell cancer were examined. The extracts had previously been subject to bioassay in rats. The intent of the examination was to determine if the vasopressin content could be confirmed immunologically. The results compared favorably with the values obtained by biological assay.
A method for detecting the presence of bacteria in urine was developed which utilizes the bioluminescent reaction of adenosine triphosphate with luciferin and luciferase derived from the tails of fireflies. The method was derived from work on extraterrestrial life detection. A device was developed which completely automates the assay process.
Progress in physics and its subfields is presented and the contribution of physics is related to progress in other scientific disciplines and the manner in which these have been utilized by our civilization. The future course of endeavor in the various subfields of physics and the extent to which these will require resources of manpower, facilities, and funding are discussed. The rational responses of the total research effort in physics to alternative funding levels are assayed.
Microbial survival in deep space environment, contamination of planets by nonsterile flight hardware, and hazards of back contamination are among the topics covered in papers concerned with the analytical basis for planetary quarantine. The development of the technology and policies of planetary quarantine is covered in contributions on microbiologic assay and sterilization of space flight hardware and control of microbial contamination. A comprehensive subject index is included. Individual items are abstracted in this issue.
Study carried out to obtain some notion of the initial phasing and interactive effects among some hormones known to be responsive to vibration stress. Sprague-Dawley derived rats were exposed to the acute effects of confinement and confinement with lateral (plus or minus G sub y) vibration. The coincident monitoring of glucose, insulin, growth hormone, and corticosterone plasma levels, during and immediately subsequent to exposure to brief low level vibration, exhibits the effects of inhibition of insulin release by epinephrine. The ability of insulin (IRI) to return rapidly to basal levels, from appreciably depressed levels during vibration, in the face of elevated levels of glucose is also shown. Corticosterone responds with almost equal rapidity, but in opposite phase to the IRI. The immuno-assayable growth hormone (IGH) dropped from a basal level of 32 ng/ml to 7.3 ng/ml immediately subsequent to vibration and remained at essentially that level throughout the experiment (60 min). Whether these levels represent a real fall in the rat or whether they merely follow the immuno-logically deficient form is still in question.
A sensitive primary amine assay, capable of detecting 10 to the minus 11th g and utilizing the determination of the amine N-2,4-dinitrophenyl derivative by electron-capture gas chromatography is described. The method is exemplified by the determination of cyclohexylamine in sodium cyclamate.
Investigation of the response of pocket mice to Co 60 irradiation delivered at two times of day - namely, the predicted high and low points of the metabolic rate. The validity of torpor as an assay of the circadian period of body temperature in pocket mice and as a basis for selecting irradiation times is examined. A study is made of the mitotic activity in the pocket mouse intestinal epithelium as an example of a physiological rhythm which might influence radiation sensitivity. The results of tests in which pocket mice were exposed to ionizing radiation at two different times of day are cited. It is found that under the investigated conditions pocket mice irradiated during their metabolically active period (2330 hr) live significantly longer than those irradiated while their metabolic rate is low (0900 hr).
Renin is a proteolytic enzyme secreted by the kidney. Techniques for the direct measurement of renin content of human blood are not available at the present time. Two of the best known causes of remediable hypertension can be diagnosed from abnormalities in renin activity and aldosterone production. In renovascular hypertension, renin secretion is increased because of impaired glomerular perfusion. The renin activity assay, when applied in a carefully controlled fashion, is a useful screening test for treatable causes of hypertension.
Commercially available equipment can be modified to provide automated system for assaying drug metabolism by continuous flow-through. System includes steps and devices for mixing drug with enzyme and cofactor in the presence of pure oxygen, dialyzing resulting metabolite against buffer, and determining amount of metabolite by colorimetric method.
An exploration was made of enzyme activities in soil, including abundance, persistence and localization of these activities. An attempt was made to develop procedures for the detection and assaying of enzymes in soils suitable for presumptive tests for life in planetary soils. A suitable extraction procedure for soil enzymes was developed and measurements were made of activities in extracts in order to study how urease is complexed in soil organic matter. Mathematical models were developed, based on enzyme action and microbial growth in soil, for rates of oxidation of nitrogen as nitrogen compounds are moved downward in soil by water flow. These biogeochemical models should be applicable to any percolating system, with suitable modification for special features, such as oxygen concetrations, and types of hydrodynamic flow.
The use of collecting foils and lunar material to assay the isotopic composition of the solar wind is reviewed. Arguments are given to show that lunar surface correlated gases are likely to be most useful in studying the history of the solar wind, though the isotopic abundances are thought to give a good approximation to the solar wind composition. The results of the analysis of Surveyor material are also given. The conditions leading to a significant component of the interstellar gas entering the inner solar system are reviewed and suggestions made for experimental searches for this fraction. A critical discussion is given of the different ways in which the basic solar composition could be modified by fractionation taking place between the sun's surface and points of observation such as on the Moon or in interplanetary space. An extended review is made of the relation of isotopic and elemental composition of the interplanetary gas to the dynamic behavior of the solar corona, especially processes leading to fractionation. Lastly, connection is made between the subject of composition, nucleosynthesis and the convective zone of the sun, and processes leading to modification of initial accretion of certain gases on the Earth and Moon.