Biomedical subjects

S Boser

Publications and source records attributed to S Boser.

3 recordsLinked to original sources

PubMed2002

Crickets in space: morphological, physiological and behavioral alterations induced by space flight and hypergravity.

"Crickets in Space" was a Neurolab experiment by which the balance between genetic programs and the gravitational environment for the development of a gravity sensitive neuronal system was studied. The model character of crickets was justified by their external gravity receptors, identified position-sensitive interneurons (PSI) and gravity-related compensatory head response, and by the specific relation of this behavior to neuronal arousal systems activated by locomotion. These advantages allowed to study the impact of modified gravity on cellular processes in a complex organism. Eggs, 1st, 4th and 6th stage larvae of Acheta domesticus were used. Post-flight experiments revealed a low susceptibility of the behavior to micro- and hypergravity while the physiology of the PSI was significantly affected. Immunocytological investigations revealed a stage-dependent sensitivity of thoracic GABAergic motoneurons to 3 g-conditions concerning their soma sizes but not their topographical arrangement. The morphology of neuromuscular junctions was not affected by 3 g-hypergravity. Peptidergic neurons from cerebral sensorimotor centers revealed no significant modifications by microgravity (micro g). The contrary physiological and behavioral results indicate a facilitation of 1 g-readaptation originating from accessory gravity, proprioceptive and visual sense organs. Absence of anatomical modifications point to an effective time window of micro g or 3 g-expo-sure related to the period of neuronal proliferation. The analysis of basic mechanisms of how animals and man adapt to altered gravitational conditions will profit from a continuation of the project "Crickets in Space".

Adaptation, Physiological↗

PubMedDate not supplied

Crickets in space.

"Crickets in Space" (CRISP) was a Neurolab experiment by which the balance between genetic programs and the gravitational environment for the development of a gravity sensitive neuronal system was studied. The model character of crickets was justified by their external gravity receptors, identified position-sensitive interneurons (PSI) and gravity-related compensatory head response, and by the specific relation of this behavior to neuronal activation systems. These advantages allowed us to study the impact of modified gravity on cellular processes in a complex organism. Eggs, 1st, 4th and 6th stage larvae of Acheta domesticus were used. Post-flight experiments revealed a low susceptibility of the behavior to microgravity and hypergravity (hg) while the physiology of the PSI was significantly affected. Immunocytological investigations revealed a stage-dependent sensitivity of thoracic GABAergic motoneurons to 3g-conditions concerning their soma sizes but not their topographical arrangement. Peptidergic neurons from cerebral sensorimotor centers revealed no significant modifications by microgravity. The contrary physiological and behavioral results indicate a facilitation of 1g-readaptation by accessory gravity. proprioceptive and visual sense organs. Absence of anatomical modifications point to an effective time window of microgravity or hg-exposure related to the period of neuronal proliferation. Grant numbers: 50WB9553-7.

Adaptation, Physiological↗

PubMedDate not supplied

Bronchial casts of human lungs using negative pressure injection.

Negative-pressure casting techniques have been used for obtaining silicone rubber casts of the avian respiratory system, which contains minute air capillaries, noncompressible hollow bones, and highly flexible air sacs. The possibilities of this technique for the study of human airway diseases, which present technical difficulties similar to those of avian lungs, are investigated here. Left lungs from patients with various obstructive lung diseases or with normal lungs were fixed at autopsy under 25 cm H2O airway pressure with 2.5% phosphate-buffered glutaraldehyde. Cannulated, isolated lobes were placed in a vacuum chamber, and Dow Corning 734 RTV silicone elastomer, diluted with 10% low-viscosity silicone oil, was introduced into the airways at--10 kPa. Following complete polymerization, the tissue was microdissected to reveal the lung cast in situ, and histological sections were obtained for correlative studies. The tissue was then macerated in 5.25% sodium hypochlorite. The total time from fixation to finished cast was 3-4 days. Linear shrinkage of the elastomer was less than 1% in glutaraldehyde or water and between 1 and 2% in bleach. The negative-pressure injection technique enabled complete and accurate filling of airways to the alveolar duct level at physiological pressures and provided good delineation of blind cavities such as obstructed airways or ecstatic mucous gland ducts. The technique proved useful for the study of obstructive lung disease and should also prove useful for modelling aerosol deposition in diseased lungs.

Bronchi↗