Altered Growth of Animals After Continual Centrifugation

Two different animals have demonstrated an accelerated growth after prolonged centrifugation. This report is primarily concerned with larvae of the common fruit fly, Drosophila melanogaster, after 24 hour periods of centrifugation at fields between 2200 and 3300 G\u27s. Similar studies are reported for the laboratory white mouse, Mus musculus after seven days of centrifugation at 7 G\u27s. The faster growth is possibly due to more efficient growth, resulting as an adaptation to greater gravity. Such a suggestion is supported by the finding that centrifuged larvae exhibit a reduced oxygen requirement for growth

Growth of the White-Mouse Gastrocnemius Muscle II. In Non-Terrestrial Gravity

Exposure of white mice (Swiss Webster, female; NLW, male and female) to 1.5 to 7.0 G\u27s of chronic centrifugation from the age of 5 weeks for durations of 1 to 8 weeks is known to cause some reduction in body growth. However, the retardation of muscular development was not as drastic. When corrections were made for differences between experimental and control body mass by means of Huxley\u27s Equation for Heterauxic Growth, the muscles of experimental mice were seen to be larger than those of control animals of the same size. The measurements of muscle size, in order of increasing high-G response were: wet mass, dry mass, and noncollagen nitrogen (NCN) content. These data were examined in terms of the Huxley Heterauxic Equation, as modified from a consideration of Galileo\u27s Principle of Similitude: muscle size ∝(inertial field) (body mass)4/3. Although all experimental muscle measurements (relative to constant body size) increased with centrifugation, any single detected compensation was much less than the total compensation predicted by this equation. The best empirical relationship found for high-G data was a linear one between the logarithm of effect upon muscles size and logarithm of effect upon body size

Growth of the White-Mouse Gastrocnemius Muscle I. In Terrestrial Gravity

The gastrocnemius muscle from white mice (Swiss Webster, female; NLW, male and female; varying in age from 6 to 13 weeks and in body mass from 8 to 36 gm) were analyzed by means of Huxley\u27s Equation for Heterauxic Growth where double logarithmic plots were performed of muscle size as a function of body mass. These mice had been grown in normal gravity. Relative wet mass, relative dry mass, and percent dry mass did not display significant changes with body mass. Percent noncollagen nitrogen [NCN] in the dry muscle, however, did show an effect which was not significantly different from that anticipated from Galileo\u27s Principle of Similitude: [NCN] ∝ (Body Mass)1/3

Food Consumption of Mice During Continual Centrifugation

High gravity simulated by continual centrifugation can evoke a slower growth with mice and other organisms. For white mice a transient reduction in food intake also occurs and is believed to be, in part, responsible for the reduced growth. Fields as high as 7 G\u27s were employed. Mice of ages which varied from one to seven weeks at the onset of exposure were studied. A more drastic decrement in food consumption occurred with the older mice at higher field intensities

Growth of Turtles During Continual Centrifugation

Juvenile Red Eared turtles (Pseudemys scripta elegans) were continuously centrifuged for as long as 9 weeks at 5 and 6 times the Earth\u27s gravity. On a carapace-length basis growth was 159±75% more at 5 G than under control conditions (1 G). These results were contrary to those with young mice at comparable fields in which the mice displayed a slower growth rate than their controls. The nature of the response appears to be dependent upon the feeding pattern

Comparative Study of Effects of Gravity on the Growth of Hamsters and Mice

Syrian golden hamsters appear to withstand gravitational stress better than white mice. When these animals were subjected to four weeks of continual centrifugation at four times the Earth\u27s gravity (4 G\u27s), both showed a definite decrease in body mass during the first week, then a subnormal growth rate for the remaining three weeks of exposure as compared to their controls living within the Earth\u27s gravity (1 G)

Analysis of margin classification systems for assessing the risk of local recurrence after soft tissue sarcoma resection

Purpose: To compare the ability of margin classification systems to determine local recurrence (LR) risk after soft tissue sarcoma (STS) resection. Methods: Two thousand two hundred seventeen patients with nonmetastatic extremity and truncal STS treated with surgical resection and multidisciplinary consideration of perioperative radiotherapy were retrospectively reviewed. Margins were coded by residual tumor (R) classification (in which microscopic tumor at inked margin defines R1), the R+1mm classification (in which microscopic tumor within 1 mm of ink defines R1), and the Toronto Margin Context Classification (TMCC; in which positive margins are separated into planned close but positive at critical structures, positive after whoops re-excision, and inadvertent positive margins). Multivariate competing risk regression models were created. Results: By R classification, LR rates at 10-year follow-up were 8%, 21%, and 44% in R0, R1, and R2, respectively. R+1mm classification resulted in increased R1 margins (726 v 278, P < .001), but led to decreased LR for R1 margins without changing R0 LR; for R0, the 10-year LR rate was 8% (range, 7% to 10%); for R1, the 10-year LR rate was 12% (10% to 15%) . The TMCC also showed various LR rates among its tiers (P < .001). LR rates for positive margins on critical structures were not different from R0 at 10 years (11% v 8%, P = .18), whereas inadvertent positive margins had high LR (5-year, 28% [95% CI, 19% to 37%]; 10-year, 35% [95% CI, 25% to 46%]; P < .001). Conclusion: The R classification identified three distinct risk levels for LR in STS. An R+1mm classification reduced LR differences between R1 and R0, suggesting that a negative but < 1-mm margin may be adequate with multidisciplinary treatment. The TMCC provides additional stratification of positive margins that may aid in surgical planning and patient education

Experimental and Mathematical Techniques for Kinetic Studies of Larval Fruit Fly Growth

Techniques have been developed in our laboratory which permit the study of growth patterns under a variety of experimental conditions. The experimental subject under investigation is the larva of the common fruit fly Drosophilia melanogaster. Studies involving exposure of the organism to thermal, gravitational, electromagnetic, and magnetic agents have already been conducted. A particular advantage of employing the larvae is that they possess a relatively rapid and simple growth pattern from which experimental constants can be obtained and statistically analyzed. During their 96-hour growth period, the approximate time from the hatching of the egg to pupae formation, the larvae need only be interrupted for about one-half hour each day for purposes of measurement. Growth patterns have been fitted to curves predicted by Compound-Interest and Verhulst-Reed-Pearl Equations. During the early growth phase excellent fit can be obtained to the exponential curve predicted by the former equation

Axial Skeletal Location Predicts Poor Outcome in Ewing's Sarcoma: A Single Institution Experience

Introduction. Ewing's sarcomas (EWSs) of bone and soft tissue are neuroectodermal tumors that affect both axial and appendicular locations. We hypothesized that axial location predicted poor outcome in EWS patients. Materials and Methods. Sixty-seven patients (57 with bone EWS and 10 with soft tissue EWS) were identified from our database. Thirty-four (51%) had axial EWS and 33 (49%) had appendicular EWS. Statistical analyses identified predictors of poor outcome. Results and Discussion. Axial location, large size, metastases at presentation, lack of definitive treatment, and positive surgical margins all correlated with poor outcome in univariate analysis. In multivariate analysis, axial location still predicted poor outcome when adjusted for pretreatment variables. Axial location was not statistically predictive of poor outcome when adjusted for treatment variables. Conclusions. Anatomic location has a negative effect on outcome in EWS that cannot be completely explained by pretreatment or treatment factors. Additional studies are required to determine if there is a biologic difference between axial and appendicular EWS

Chronic Centrifugation of Labyrinthectomized, Growing Turtles

A 1-G space-based centrifuge will be necessary before controlled, bio-medical weightlessness experiments can be performed. Some argue that centrifuges of prohibitive dimensions are necessary. Labyrinthectomized, hatchling, Red-Eared Turtles (Pseudemys scripta elegans) which had grown to a length of 45 mm at 5 G\u27s (200 rpm 10 cm radius) displayed the same greater shell height (21.7 ± 0.4 vs, 20.0 ± 0.3 mm at 1 G) that was observed at 5 G\u27s with nonlabyrinthectomized, centrifuged turtles. If other effects of centrifugation can also be attributed to artificial gravity rather than rotation, a space-based centrifuge radius as short as 10 cm (1 G at 100 rpm) is suggested