Individual Growth Curve Analysis Research Articles

Transfer of growth hormone (GH) transgenes into Arctic charr ( Salvelinus alpinus L.) : I. Growth response to various GH constructs

Four constructs containing salmonid growth hormone (GH) genes were transferred to Arctic charr ( Salvelinus alpinus L.). Cytomegalovirus (CMV) and piscine metallothionein B (OnMT) and histone 3 (OnH3) promoters connected to sockeye salmon growth hormone 1 gene (OnGH1) were used for ectopic expression, and Atlantic salmon growth hormone 2 gene with 5′flanking region (SsGH2) was tested for pituitary-specific expression. Charr carrying the OnGH1 constructs showed a dramatic increase in growth rate. The 10-month old transformed fish were 14-fold heavier than control siblings. The ability of the CMVGH1 construct to promote growth was greater than that obtained in fish with piscine promoters. Analysis of individual growth curves of charr carrying the OnH3GH1 transgene indicated a stable ratio of specific growth rates in transformed and control fish regardless of fish size. No alteration in growth performance was found in fish carrying the SsGH2 transgene. There was evidence that the transformed rainbow trout ( Oncorhynchus mykiss) were unable to produce SsGH2 mRNA in their pituitary glands. The presence of the transgene in various tissues was examined in trout to evaluate the reliability of one-tissue sampling.

An individual growth curve analysis of activity level from infancy to 6 years

An individual growth curve analysis of activity level from infancy to 6 years

Preinjury family environment as a determinant of recovery from traumatic brain injuries in school-age children

Previous studies of childhood traumatic brain injury (TBI) have emphasized injury-related variables rather than environmental factors as predictors of recovery. We addressed this concern using data collected during a prospective study of children with either TBI or orthopedic injuries (OI) and their families. Participants included 53 children with severe TBI, 56 with moderate TBI, and 80 with OI, all from 6 to 12 years of age at the time of injury. Measures of the preinjury family environment were collected shortly after the injury (baseline). Child cognitive and behavioral outcomes were assessed at baseline and at 6- and 12-month follow-ups. Individual growth curve analyses showed that measures of the preinjury family environment consistently predicted both the level of cognitive and behavioral functioning at 12 months postinjury and the rate of intraindividual change during the 12-month follow-up period, even after taking into account group membership and injury severity. In some cases, the preinjury family environment was a significant moderator of the effect of TBI, buffering its impact in high-functioning families and exacerbating it in low-functioning families. Thus, preinjury environmental factors predict recovery following TBI in children, even after accounting for injury-related variables.

How much weight gain occurs following smoking cessation? A comparison of weight gain using both continuous and point prevalence abstinence.

Estimates of postcessation weight gain vary widely. This study determined the magnitude of weight gain in a cohort using both point prevalence and continuous abstinence criteria for cessation. Participants were 196 volunteers who participated in a smoking cessation program and who either continuously smoked (n = 118), were continuously abstinent (n = 51), or who were point prevalent abstinent (n = 27) (i.e., quit at the 1-year follow-up visit but not at others). Continuously abstinent participants gained over 13 lbs. (5.90 kg) at 1 year, significantly more than continuously smoking (M = 2.4 lb.) and point prevalent abstinent participants (M = 6.7 lbs., or 3.04 kg). Individual growth curve analysis confirmed that weight gain and the rate of weight gain (pounds per month) were greater among continuously smoking participants and that these effects were independent of gender, baseline weight, smoking and dieting history, age, and education. Results suggest that studies using point prevalence abstinence to estimate postcessation weight gain may be underestimating postcessation weight gain.

Biometrical analysis of individual growth curves.

Longitudinal data for height (length) between birth and 2 years of age were examined for 690 Dutch Registry twin pairs. A two-stage analysis was performed, where individual growth curves were first fit to available data for each subject using a linear multiple regression procedure and estimated individual growth curve parameters were then subjected to multivariate biometrical analysis. Quadratic polynomial curves were found to adequately represent observed growth patterns for the majority of cases (median R2 = .98). A specific scalar model of sex limitation best characterized individual variation in growth curve parameters. That is, there was significantly greater genetic variation for boys than for girls in both the predicted length and rate of growth at 1 year of age and the amount of deceleration in individual growth curves across age.

Longitudinal Analyses of Academic Achievement

Mathematical models of individual growth are the basis for analyzing academic achievement over time. This study demonstrates that much can be learned about academic growth from the analysis of individual growth curves. In addition, we illustrate the aggregation of individual responses to provide descriptions of institutional growth. Although more efficient statistical methods are available, the simple approach taken here serves to demonstrate the logic and approach to analyzing longitudinal data.

Effects of Laser UV-Microirradiation (λ = 2573 Å) on Proliferation of Chinese Hamster Cells

CREMER, C., CREMER, T., ZORN, C., AND SCHOELLER, L. Effects of Laser UV-Microirradiation (X = 2573 A) on Proliferation of Chinese Hamster Cells. Radiat. Res. 66, 106-121 (1976). A laser uv-microbeam with a wavelength of 2573 A* having a minimum spot diameter of approx 0.5 sm was used to microirradiate interphase cells of a V-79 subline of Chinese hamster cells. The incident energy necessary to induce a significant decrease of proliferation was 30 to 60 times larger after microirradiation of cytoplasm as compared with microirradiation of nucleoplasm. The mean value of relative cell numbers 40 hr after irradiation as a function of incident energy did not differ whether the cells were microirradiated lying singly or together in small groups. Analysis of individual growth curves of singly lying cells microirradiated in the nucleoplasm with the same energy showed heterogeneous reactions. The incident energy per cell compatible with proliferation of about 50% of the cells after microirradiation of nucleoplasm was approx. 2 X 10-3 ergs. From this value it is suggested that the energy density within the focus was in the region of several thousand ergs per square millimeter. Photochemical effects are thought to be the cause of growth disturbance,while thermal effects are excluded.

Physical Growth from Birth to Maturity

The present emphasis seems to be not so much the establishment and comparison of group growth curves, but rather the establishment and analysis of individual growth curves from well-planned, carefully controlled long-time studies of large numbers of individuals. Wolff (54, 55) in the Hagerstown, Maryland, study made yearly measurements from 1937 to 1940 of a large group of girls and boys. He concluded that it is not so much sex differences but growing height which determines weight. None of the three indexes used remained constant over the whole growth period. He concluded that growth cannot be measured by the same heightweight ratio at different ages. Wolff (55) also discussed the tendency for recent child population groups to show an increase in weight. He noted smaller families as a possible explanation; also that, in Washington County, higher socio-economic groups since 1920 have contributed a larger proportion of children than in former years. Robinow (40) established norms for the variability of weight and height increments from birth to six years of age. Since no sex differences were present he combined the data into one set of norms. During the first year of life the ratio of growth decreased rapidly and height was less variable than weight as regards increments. Vickers and Stuart (47) have recognized the relation of body size, proportions, and rate of growth to physical health and fitness, and have pointed out the importance of periodic observations to prevent retardation. They suggested three measurements: (a) body weight, (b) height (recumbent length), and (c) breadth of chest and pelvis (recumbent) as being most useful to the pediatrician.