An introduction to the Internet.
Explore the source record for details and available documents.
Computer Communication Networks↗
Biomedical subjects
J E Volz
Publications and source records attributed to J E Volz.
An introduction to the Internet.
Explore the source record for details and available documents.
Computer Communication Networks↗
Force delivery properties of colored elastomeric modules.
Elastomeric chains have been used by clinicians for some time to accomplish various treatment objectives. Recently, a number of manufacturers have added colored elastomeric chains to their inventories. The present study was designed to investigate the force delivery capabilities and dimensional stability of these new colored chains. Four different colors of short filament configuration produced by three manufacturers were examined. The force delivery capabilities of each chain were tested at 0 hours and, after storage at 37 degrees C in air, distilled water, and artificial saliva, at 1 hour, 4 hours, 24 hours, 1 week, 2 weeks, and 3 weeks. A universal testing machine was used to determine the amount of distraction necessary to generate 150 and 300 gf. Dimensional measurements were assessed initially and, after exposure to a simulated oral environment, at 1, 2, and 3 weeks. The data from the force delivery portion of the study were analyzed with a 4-factor factorial analysis of variance. The data compiled from the dimensional stability portion were subjected to a 3-factor factorial analysis of variance. Follow-up Bonferroni simultaneous t tests (family-wise a priori alpha p < 0.05) was used to determine statistical significance of the differences among sets of means. All colored elastomeric chains in the study appeared capable of initially generating force levels compatible with tooth movement. After 24 hours of storage in liquid, the amount of distraction needed to produce 150 and 300 gf substantially increased. The amount of increased need varied among manufacturers. All chains showed an increase in dimensional measurements after 1 week, with little change thereafter.
Analysis of Variance↗
Feeding in infancy, adipose tissue cellularity and obesity.
Female Sprague-Dawley rats were raised in litters of four (L4), nine (L9) and 24 (L24). The well nourished L4 rats grew insignificantly larger, heavier and fatter than the L9 controls; the underfed L24 rats remained small and stunted, and had absolutely and relatively less adipose tissue than the L4 and L9 rats. Approximately half of the rats of these three groups were fed a high-fat diet from age 18 to 43 weeks. Almost all of the rats in the fat-fed groups became obese. The amount of adipose tissue expressed as percent body weight was essentially the same in all three fat-fed groups, with the greatest relative enlargement of fat stores and increase in fat cell number in the 24-litter rats. The results show that the feeding pattern during adult life is of greater importance than early feeding experiences. The literature regarding overfeeding and underfeeding during early life is reviewed; it confirms that early overfeeding does not predispose to obesity in later life and that early underfeeding does not prevent or diminish the development of nutritional obesity and adipose tissue hypercellularity. Early underfeeding seems to affect more the regulation of the feeding behavior than the intrinsic functions and growth potential of adipose tissue; it may even stimulate the development of obesity.
Adipose Tissue↗
A possible non-oncogenic effect of C type bone cell virus on serum calcium levels of potentially leukemic mice.
In bone of C3H/Fg mice, particles structurally identical to C-type leukemia virus arise from membranes of osteocytes and osteoblasts. Although these virus apparently do not induce morphologic or neoplastic change in bone they may have other, more subtle, effects. Thus, comparison of sera from male C3H/Fg mice, a high leukemia-prone strain, with C57BL and C3H/HeJ mice, low leukemia strains which do not contain C-type virus in bone, reveals that serum calcium levels are significantly lower in the former than in the latter. Further, when C3H/Fg mice develop frank leukemia there is a corresponding increase in virus particles while the serum calcium concentration levels fall to even lower values. The presence of leukemia itself appears not to be the cause as indicated by the failure of implanted lymphocytic leukemic cells in C3H/Fg mice to significantly affect serum calcium concentration. It is postulated that the effects of the virus could be due either to increased osteo blastic activity or to inhibition of osteocytic osteolytic activity or to both.
Animals↗
Variations in serum calcium between strains of inbred mice.
Serum calcium concentrations of C3H/Fg, C3H/HeJFg, AKR/Fg, A/Fg, and LCS/Fg mice were compared at 4 and 7 mo of age. In the C3H/Fg and A-strain mice, calcium levels did not differ significantly between the 2 strains nor between the 2 age groups. The C3H/HeJFg, LCS/Fg, and C57BL/Fg strains formed a distinct group with similar calcium levels, but at a significantly higher level than C3H/Fg and A/Fg group. Again there was no significant difference between the 4- and 7-mo groups. The AKR/Fg strain was distinct from both groups in that higher calcium levels characteristic of the second group (C3H/HeJFg, LCS/Fg, and C57BL/Fg, were seen at 4 mo of age, but lower calcium levels similar to those of the C3H/Fg and A/Fg strains were found at 7 mo of age.
Age Factors↗