Cross-sectional data on 2799 subjects from five different populations and longitudinal data on 113 older adults indicate continuing adult bone growth in the second metacarpal. Similar B-decade increases in the size of the cranium confirm continuing bone growth as a general phenomenon not necessarily related to weightbearing or flexion stress and representing an increase of approximately 10% in skeletal volume concomitant with the major age-associated decrease in skeletal mass.In 1964, Smith and Walker provided cross-sectional radiographic evidence for continuing "expansion" of the femur in women aged 45-90. Trotter and Peterson ('67), using skeletalized femora have given confirmation to this trend. Epker, Kelin and Frost ('65) similarly reported an increase in the size of the periosteal envelope through the seventh decade in rib cross sections of subjects of both sexes. Moore ('55) earlier published separate cross-sectional data indicating continuing growth of the cranial vault through late adulthood, thus indicating that weight-bearing, flexion-stressed bones axe not unique in the apparent property of continuing growth.With cross-sectional data from five populations at hand, and having both longterm and short-term longitudinal data from a single ongoing study population, we have been concerned with three aspects of the problem of continuing bone growth. First, there is the question of such adult growth in various bones throughout the body, weight-bearing, flexion-stressed and otherwise. Second, there is the problem of generalization-whether such bone expansion is population-limited or not and sexspecific or not. Third, there is the problem of confinnation of such continuing growth on an individual basis in order to rule out artifacts of sampling and differential survival.It is the purpose of the present study to explore continuing bone growth in two populations from the United States and AM. J. Pays. ANTHROP., 26: 313-318.three Central American populations, using longitudinal data to further test for individual trends. It is the additional purpose of this study to investigate adult bone growth in both weight-bearing bone and in bone not subject to compression or flexion stress in order to determine whether such mechanical factors play a necessary role in continuing bone growth. METHODS AND MATERIALSThis study is based upon vernier caliper measurements of the second metacarpal on pastero.anterior hand radiographs from five different population samples, one skeletal and four living. 2799 subjects are represented in the cross-sectional study.
3- ABSTRACTSubperiosteal and medullary cavity diameters of 91 Guatemalan boys hospitalized with a diagnosis of protein-calorie malnutrition show a slight but significant increase in total width but a marked reduction at the endosteal surface, and in cortical area and percent cortical area, indicative of continuing subperiosteal apposition and a dramatic excess of endosteal resorption.m In previous studies we were able to demonstrate tubular bone loss during the course of protein-calorie malnutrition in infants and children, as apart from simple failure to grow (Garn et al., '64a,b; Garn, Rohmann and Guzmann, '66; Garn, Rohmann and Silverman, '67). Our work closely confirmed the bone-mineral determinations of Fletcher and Garrow ('64) and indicated a magnitude of tissue bone loss as great as 40%. We did not analyze the two bone surfaces, nor did we have access to the data from the Guatemalan Nutritional Survey. Recently, however, we have extended our analysis, using such national norms, and can document the surface-specific nature of bone loss in proteincalorie malnutrition in Central America.Comparing radiogrammetric data on metacarpal widths of boys hospitalized with an admission diagnosis of Kwashiorkor, with our recent national survey data (Garn and Rohmann, '66) no systematic reduction in outer bone width is evident. Rather, subperiosteal diameters of the affected boys are slightly but significantly larger than expectancy, using a chi-squared test (x2 = 4.05, p = 0.05). These data are shown in the first figure, and indicate that outer bone widths are not necessarily diminished, despite other growth failures.However, there is a marked reduction of cortical bone at the endosteal surface, compared to the sex-specific Guatemalan venile protein-calorie malnutrition is surface specific, and, as in adult bone loss, bone is lost at the endosteal surface and not at the subperiosteal. The subperiosteal surface may even continue to gain, in both juvenile and adult bone loss. 153
Additional and extended data on 2726 subjects from Costa Rica, Honduras, Nicaragua and Panama provide confirming evidence for continuing bone expansion of the second metacarpal at midshaft. As shown in 4924 subjects from eight populations, subperiosteal apposition is more rapid in the female than in the male, and accounts for a net increase of 10% in cross-sectional area from age 25 to age 85. Unlike endosteal resorption, which is precipitous in onset, adult subperiosteal gain is continuous from the third through the ninth decades.
This chapter provides critical information on the physiological and behavioral responses common to pigs experiencing disease and describe animal-based outcomes directly impacted during a disease state. In addition, timely tools to prevent and monitor disease at the herd level are discussed and disease prevention techniques are described. Lastly, the chapter explores strategies for managing sick pigs as the critical next step when prevention is unsuccessful.
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