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Biomedical subjects

R W Ballard

Publications and source records attributed to R W Ballard.

15 recordsLinked to original sources
PubMed1994

ANP binding sites are increased in choroid plexus of SLS-1 rats after 9 days of spaceflight.

Specific alpha-rat 28-amino acid atrial natriuretic peptide [ANP(99-126)] (rANP) binding sites in choroid plexus and meningia of rats flown for 9 days on the mission STS-40 (SLS-1) carried on the space shuttle Columbia in June 1991 were analyzed after incubation of brain sections with 125I-rANP and autoradiography, using computer-assisted microdensitometric image analysis. The number of 125I-rANP binding sites (expressed by Bmax values) in the choroid plexus of lateral and third ventricles of these rats was significantly increased (x 1.5-2.5 times), as compared with that found in ground control rats. No differences in the binding affinity (deducible from Kd values) were observed at the level of these structures. The choroid plexus from the fourth ventricle of the same rats displayed no changes in the binding capacity or affinity after the spaceflight. Meningia from the rats flown in space did not demonstrate any significant modifications of the number of 125I-rANP binding sites, but displayed a significant increase in Kd values, which suggested a reduced affinity of the meningeal ANP receptors during a 9-d spaceflight. The possibility that atrial natriuretic peptide may be involved in the regulation of fluid and electrolyte fluxes in the brain, during adaptation to microgravity, through modified expression of specific high affinity receptors, mainly in choroid plexus from forebrain or in meningia, must be considered.

Animals↗
PubMed1992

Flying U.S. science on the U.S.S.R. Cosmos biosatellites.

The USSR Cosmos Biosatellites are unmanned missions with durations of approximately 14 days. They are capable of carrying a wide variety of biological specimens such as cells, tissues, plants, and animals, including rodents and rhesus monkeys. The absence of a crew is an advantage with respect to the use of radioisotopes or other toxic materials and contaminants, but a disadvantage with respect to the performance of inflight procedures or repair of hardware failures. Thus, experiments hardware and procedures must be either completely automated or remotely controlled from the ground. A serious limiting factor for experiments is the amount of electrical powers available, so when possible experiments should be self-contained with their own batteries and data recording devices. Late loading is restricted to approximately 48 hours before launch and access time upon recovery is not precise since there is a ballistic reentry and the capsule must first be located and recovery vehicles dispatched to the site. Launches are quite reliable and there is a proven track record of nine previous Biosatellite flights. This paper will present data and experience from the seven previous Cosmos flights in which the US has participated as well as the key areas of consideration in planning a flight investigation aboard this Biosatellite platform.

Animals↗
PubMed1991

Man in space: the use of animal models.

Animals have traditionally preceded man into space. During animal and human travels in space over the past almost 30 years, numerous anatomical, physiological, and biochemical changes have been observed. In order to safely qualify humans for extended duration space missions, scientific research needs to be performed. It may be possible to achieve many of these research goals with flight crews serving as experimental subjects; however, to do this with human subjects alone is impractical. Therefore, the use of animal surrogates as experimental subjects is essential to provide the missing information on the effects of spaceflights, to validate countermeasures, and to test medical treatment techniques which will be necessary for long duration missions. This research to assure human health, safety, and productivity in future extended duration space flights will include flights on NASA's Space Shuttle, unmanned biosatellites, and the Space Station Freedom.

Aerospace Medicine↗
PubMed1981

Hemangiopericytoma of the tracheal wall.

A hemangiopericytoma occurred on the posterior tracheal wall in a 46-year-old man. A review of the pathologic findings showed that compressed groups of capillaries were lined by an intact reticulin sheath that was surrounded by spindle-shaped pericytes. The ultramicroscopic findings of small spindle cells with a surrounding basal lamina and intracellular microfilaments in the absence of neurosecretory granules are important diagnostic features. Emphasis is placed on the impossibility of differentiating benign and malignant lesions pathologically, the need for long-term clinical follow-up, and the necessity for adequate complete surgical resection of these lesions. The use of a surgical approach to the posterior side of the tracheal wall can prevent postoperative stenosis.

Diagnosis, Differential↗
PubMed1980

Job's syndrome.

Job's syndrome is characterized by the clinical features of fair skin, red hair, recurrent cold staphylococcal skin abscesses with concurrent other bacterial infections and skin lesions. This case report chronicles a classic presentation of Job's syndrome. A brief review of the otolaryngological presentations of immune deficiencies is presented. Other than its relationship to the manifestations of other immunological defects, Job's syndrome is of interest to the otolaryngologist because of the head and neck infections represented in its clinical expression. Familiarity with phenotypic and laboratory manifestations of such diseases will enable earlier recognition and treatment of this syndrome.

Abscess↗
PubMed1972

Deoxyribonucleic acid homologies among some Pseudomonas species.

Phylogenetic relationships among a number of strains belonging to the genus Pseudomonas were explored by the use of in vitro deoxyribonucleic acid (DNA) hybridization. The fluorescent nomenspecies (P. fluorescens, P. putida, P. aeruginosa, P. cichorii, P. syringae, and related species), as well as the nonfluorescent species P. stutzeri, P. mendocina, P. alcaligenes, and P. pseudoalcaligenes, were shown to belong to a single DNA homology complex which is isolated from other Pseudomonas species that have been studied [P. cepacia (= P. multivorans), P. caryophylli, P. marginata (= P. alliicola), P. pseudomallei, P. acidovorans, P. testosteroni, P. solanacearum, P. diminuta, P. facilis, P. delafieldii, P. saccharophila, P. palleronii]. A limited numerical analysis of the phenotypic properties of the examined strains supported, with some exceptions, their previous allocation to nomenspecies and biotypes. The internal structure and nomenclature of the "P. fluorescens homology complex" are discussed.

Biological Evolution↗
PubMedDate not supplied

Nasal blastoma: a light and electron microscopic study.

The first light and electron microscopic study of a nasal blastoma is reported. Analogous to a pulmonary blastoma, the tumor is composed of well-differentiated squamous and glandular epithelial elements surrounded by a spindle cell stroma. The spindle stromal cell is a myofibroblast. Eighteen months after complete surgical removal of the tumor and radiation therapy, the patient is clinically free of disease.

Adult↗