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Biomedical subjects

E R Morey

Publications and source records attributed to E R Morey.

9 recordsLinked to original sources
PubMed1992

Preosteoblast production in COSMOS 2044 rats: short-term recovery of osteogenic potential.

The influence of a 13.8-day spaceflight and approximately 8.5-11 h of recovery at 1 g on fibroblast-like osteoblast precursor cells was assessed in the periodontal ligament of rat maxillary first molars. Preosteoblasts (C + D cells), less differentiated progenitor cells (A + A' cells), and nonosteogenic fibroblast-like cells (B cells) were identified by nuclear volume analysis (i.e., A + A' = 40-79 microns 3; B = 80-119 microns 3; C + D greater than or equal to 120 microns 3). No differences were observed among flight (F), synchronous (SC), vivarium, and basal control groups in the A + A' (F: 28.0 +/- 3.7 vs. SC: 27.4 +/- 2.2), B (F: 33.1 +/- 1.4 vs. SC: 32.4 +/- 2.4), or C + D (F: 38.4 +/- 4.5 vs. SC: 39.2 +/- 1.6) cell compartments (mean +/- SE, n = 5). Compared with previous spaceflight experiments, the present data are consistent with a postflight response to replenish preosteoblasts and restore periodontal ligament osteogenic potential. These data emphasize the need to 1) unequivocally determine the flight effect by killing the animals in-flight and 2) further assess the postflight recovery phenomenon.

Animals↗
PubMed1990

Preosteoblast production 55 hours after a 12.5-day spaceflight on Cosmos 1887.

The influence of 12.5 days of spaceflight and a 55 h stressful recovery period (at 1 g) on fibroblastlike osteoblast precursor cells was assessed in the periodontal ligament (PDL) of rats that were 91 days old at launch. Nuclear morphometry was used as a marker for precursor cell differentiation in 3 microns sections cut in the midsagittal plane from the maxillary first molar. According to nuclear volume, cells were classified as preosteoblasts (C + D cells, greater than or equal to 120 microns 3) and less differentiated progenitor cells (A + A' cells, 40-79 microns 3). Compared with synchronous controls (simulated flight conditions), the 55 h postflight recovery period at 1 g resulted in a 40% decrease in the A + A' cell population, a 42% increase in the C + D cells, and a 39% increase in the number of PDL fibroblastlike cells near the bone surface. These results are consistent with a postflight osteogenic response in PDL. This recovery response occurred despite physiological stress in the flight animals that resulted in a highly significant (P less than or equal to 0.001) increase in adrenal weight. The data suggest that after spaceflight there is a strong and rapid recovery mechanism for osteoblast differentiation that is not suppressed by physiological stress.

Animals↗
PubMed1987

Nuclear morphometric analysis of osteoblast precursor cells in periodontal ligament, SL-3 rats.

Five small (55 days old, 196 +/- 5 g) (mean +/- SE) and five large (83 days old, 382 +/- 4 g) Sprague-Dawley strain, specific pathogen-free rats were exposed to a 7-day spaceflight and 12-h postflight recovery period. As measured in 3-micron sections, periodontal ligament (PDL) fibroblastlike cells were classified according to nuclear size: A + A' (40-79), B (80-119), C (120-169), and D (greater than or equal to 170 microns 3). Since the histogenesis sequence is A----A'----C----D----osteoblast, the relative incidence of A + A' to C + D is an osteogenic index. No difference in A + A' or C + D cells in small rats may reflect partial recovery of preosteoblast formation (A----C) during the 12-h postflight period. Large flight rats demonstrated increased numbers of A + A', indicating an inhibition of preosteoblast formation (A----C). At least in the older group, a 7-day flight is adequate to reduce PDL osteogenic potential (inhibition in PDL osteoblast differentiation and/or specific attrition of C + D cells) that does not recover by 12-h postflight.

Animals↗
PubMed1986

Osteoblast histogenesis in periodontal ligament and tibial metaphysis during simulated weightlessness.

According to nuclear size, fibroblast-like cells adjacent to bone surfaces in the periodontal ligament (PDL) and tibial primary spongiosa (PS) were classified as less differentiated progenitors and committed osteoprogenitors (A/A'), nonosteogenic cells (B), or preosteoblasts (C/D). The ratio of A/A' to C/D cells reflects osteogenic status of bone lining tissue. When 83-day-old rats were subjected to simulated weightlessness (S-W) for 17 d and examined for changes in osteoblast histogenesis, PDL and PS cell populations increased in A/A' cells (p less than 0.01; less than 0.05) but decreased in C/D cells (p less than 0.01; less than 0.05) compared to controls. These data indicate that the nuclear volume method, originally developed in PDL, can also be used to assess osteoblast histogenesis in PS of long bones, and that simulated weightlessness in the present experimental context interferes with osteoblast histogenesis. Since the surfaces of both weightbearing (PS) and nonweightbearing (PDL) bones were affected, systemic factors appear important in the gravity-related mechanism of osteoblast histogenesis. Although unloading of the tibia and cephalad fluid shifts occur during S-W, the data attained in this experiment could also be explained by stress and/or cessation of growth in the S-W rats.

Animals↗
PubMed1978

Inhibition of bone formation during space flight.

Parameters of bone formation and resorption were measured in rats orbited for 19.5 days aboard the Soviet Cosmos 782 biological satellite. The most striking effects were on bone formation. During flight, rats formed significantly less periosteal bone than did control rats on the ground. An arrest line at both the periosteum and the endosteum of flight animals suggest that a complete cessation of bone growth occurred. During a 26-day postflight period, the defect in bone formation was corrected. No significant changes in bone resorption were observed.

Aerospace Medicine↗
PubMed1978

The effects of phosphate depletion on bone.

Phosphate depletion causes significant changes in the composition of the cell population in bone and the metabolic activities of these cells. The data presented indicate that a vitamin D metabolite has a significant role in producing the increase in osteoclast number associated with phosphate depletion. The increased resorptive activity and number of osteoclasts leads to a marked increase in the rate of bone resorption resulting in the liberation of calcium phosphate, while the decrease in the rates of the processes involved in bone formation (matrix production, osteoid maturation, and mineralization) reduces the amount of phosphate which is removed from the circulation. Thus, all of the effects of phosphate depletion on bone are consistent with the interpretation that bone acts as a reservoir of phosphate and is used to maintain soft tissue and serum phosphate levels at the expense of bone.

Animals↗