Optimizing weight gain in pregnancy to prevent obesity in women and children.

Pregnancy is now considered to be an important risk factor for new or persistent obesity among women during the childbearing years. High gestational weight gain is the strongest predictor of maternal overweight or obesity following pregnancy. A growing body of evidence also suggests that both high and low gestational weight gains are independently associated with an increased risk of childhood obesity, suggesting that influences occurring very early in life are contributing to obesity onset. In response to these data, the US Institute of Medicine (IOM) revised gestational weight gain guidelines in 2009 for the first time in nearly two decades. However, less than one third of pregnant women achieve guideline-recommended gains, with the majority gaining above IOM recommended levels. To date, interventions to optimize pregnancy weight gains have had mixed success. In this paper, we summarize the evidence from human and animal studies linking over-nutrition and under-nutrition in pregnancy to maternal and child obesity. In addition, we discuss published trials and ongoing interventions to achieve appropriate gestational weight gain as a strategy for obesity prevention in women and their children.

Changes in Physical Activity and Television Viewing From Pre-pregnancy Through Postpartum Among a Socioeconomically Disadvantaged Perinatal Adolescent Population.

STUDY OBJECTIVE: Adolescent pregnancy contributes to accelerated trajectories of adiposity and cardiometabolic diseases. Two potentially low-cost prevention strategies include promoting physical activity (PA) and limiting television (TV) viewing. Few studies have explored these behavior patterns in perinatal adolescents. This study sought to characterize PA and TV viewing in a socioeconomically disadvantaged perinatal adolescent population. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS: A cross-sectional, retrospective, 10-item survey was used to explore behavior patterns in 79 predominantly Black (86%) postpartum adolescents. MAIN OUTCOME MEASURES: Outcomes included self-reported changes in PA from pre-pregnancy through pregnancy, and 7-day recall of PA and TV viewing in postpartum. RESULTS: The majority of adolescents (66%) reported being active on ≥3 days/week in pre-pregnancy; however, many reported low PA (≤2 days/wk) in their first (59%), second (66%), and third (54%) trimesters. Adolescents who reported being active on ≥5 days/wk in pre-pregnancy (19%) experienced first trimester PA decline, which subsequently plateaued. This group remained the most active throughout pregnancy. In postpartum, over half (54%) of all adolescents reported low PA and irrespective of PA, spent considerable time watching TV (median = 1680.0 minutes, inerquartile range = 2940). CONCLUSION: Interventions promoting PA coupled with reducing TV viewing during pregnancy and in postpartum may benefit perinatal adolescents. The findings from this study suggest that PA history is a predictor of gestational PA, and low PA and high TV viewing in postpartum underscore the need for behavioral intervention. Conducting a brief assessment of PA history in early gestation may offer important insight.

Dietary consistency and the midline sutures in growing pigs.

OBJECTIVES: The purpose of this study was to investigate the effects of reduced masticatory function on midline suture growth and morphology in growing pigs. SETTING AND SAMPLE POPULATION: The sample was 20 pigs separated into two dietary groups and raised at the Department of Anthropology, Harvard University. Midline suture specimens were analyzed at the Department of Orthodontics, University of Washington. MATERIALS AND METHODS: Ten farm pigs and 10 minipigs, all male, were randomly assigned to hard (n = 9) and soft-diet (n = 11) groups. Fluorochromic mineral labels were administered to document bone apposition, and the animals were killed after 12 weeks. Undecalcified sections of the interfrontal, interparietal, internasal, and intermaxillary sutures were evaluated for bone quantity and sutural thickness, interdigitation ratio and growth rate. RESULTS: Soft-diet pigs were characterized by a slower rate of weight gain and less bone than their hard-diet counterparts. Even after correction for weight gain, soft-diet pigs had reduced suture growth rate and thickness. However, no difference in interdigitation ratio was detected between dietary groups. CONCLUSIONS: Restriction to a soft diet reduces midline suture growth and bone apposition in the growing pig.

Who should conduct and interpret the neuropsychological assessment in sports-related concussion?

OBJECTIVE: This paper seeks to (i) describe the education and training of clinical neuropsychologists, (ii) discuss the significant differences between test administration and clinical assessment, (iii) outline the complex factors involved in psychometric test theory and test interpretation, and (iv) provide a framework for the role of clinical neuropsychologists in the interpretation and administration of neuropsychological instruments within the sports context. DESIGN: Review of pertinent professional practice, empirical and theoretical literature. INTERVENTION: Pubmed, Medline and Psych Info databases were reviewed. In total, 35 articles and 2 books were reviewed. RESULTS: The decision to return an athlete to play following sports-related brain injury is complex and requires the analysis of several sources of data. The decision is determined by a team physician; ideally within the context of a multidisciplinary team that employs comprehensive concussion surveillance and management, including baseline and post-injury neuropsychological assessment. Neuropsychologists possess the training and skill sets necessary to provide unique expertise in the assessment of cognitive functioning and post-injury neurocognitive and psychological assessment. CONCLUSIONS: Baseline neuropsychological testing is a technical procedure that can be conducted by technicians under the supervision/guidance of a neuropsychologist. Post-injury assessment requires advanced neuropsychological expertise that is best provided by a clinical neuropsychologist. Significant international differences exist with respect to the training and availability of clinical neuropsychologists, which require modification of these views on a country by country basis.

3,4-Epoxy-1-butene, a reactive metabolite of 1,3-butadiene, induces somatic mutations in Xpc-null mice.

Xpc-null (Xpc-/-) mice, deficient in the global genome repair subpathway of nucleotide excision repair (NER-GGR), were exposed by intraperitoneal (i.p.) injection to a 300 mg/kg mutagenic dose of 3,4-epoxy-1-butene (EB), to investigate NER's potential role in repairing butadiene (BD) epoxide DNA lesions. Mutagenic sensitivity was assessed using the Hprt assay. Xpc-/- mice were significantly more sensitive to EB exposure, exhibiting an average 2.8-fold increase in Hprt mutant frequency (MF) relative to those of exposed Xpc+/+ (wild-type) mice. As a positive control for NER-GGR, additional mice were exposed by i.p. injection to a 150 mg/kg mutagenic dose of benzo[a]pyrene (B[a]P). The Xpc-/- mice had MFs 2.9-fold higher than those of exposed Xpc+/+ mice. These results suggest that NER-GGR plays a role in recognizing and repairing some of the DNA adducts formed following in vivo exposure to EB. Additional research is needed to examine the response of Xpc-/- mice, as well as other NER-deficient strains, to inhaled BD. Furthermore, it is likely that alternative DNA repair pathways also are involved in restoring genomic integrity compromised by BD-epoxide DNA damage. Collaborative studies are currently underway to address these critical issues.

Condylar mineralization following mandibular distraction in rats.

The impact of mandibular distraction on condyles is poorly understood. To examine how condylar mineralization is affected, we performed distraction in 128 one-month-old rapidly and 126 three-month-old slowly growing rats. The rate of distraction was 0.0 mm (sham), 0.2 mm (slow), 0.4 mm (moderate), or 0.6 mm (rapid). From 7 to 9 rats from each rate (n = 29-32) were killed at 4 time periods (D6, D10, D24, and D38) following osteotomy. Calcein and alizarin were injected 6 and 3 days, respectively, prior to death. Methacrylate-embedded sagittal condylar sections were examined under epifluorescence, and mineral apposition rates were measured. Results indicated that: (1) rapidly growing rats showed higher mineral apposition rates (p < 0.01-0.001) than did slowly growing rats; (2) mineral apposition rates were lower in distracted sides at all times in rapidly growing rats (p < 0.05-0.01), while this side-dependency was seen only at D24 in slowly growing rats (p < 0.05); and (3) distraction rates had little effect on mineral apposition rates. Thus, mandibular distraction decreases condylar mineral apposition rates, but only in rapidly growing rats, which is related to surgery and its functional consequences, not to the distraction rate.

Human prostatic cancer cells, PC3, elaborate mitogenic activity which selectively stimulates human bone cells.

Prostatic cancer typically produces osteoblastic metastases which are not attended by marrow fibrosis (i.e., osteoblast but not stromal fibroblast proliferation). In the present study we sought to test the hypothesis that prostatic cancer cells produce factor(s) which act selectively on human osteoblasts. Such a paracrine mechanism would explain the observed increase in osteoblasts, unaccompanied by an increase in marrow fibroblasts. To test this hypothesis we investigated the mitogenic activity released by the human prostatic tumor cell line, PC3. PC3 cells have been reported previously to produce mitogenic activity for cells that was relatively specific for rat osteoblasts compared to rat fibroblasts. However, the effects of this activity on human cells has not been examined previously. PC3-conditioned medium (CM) (5-50 micrograms CM protein/ml) stimulated human osteoblast proliferation by 200-950% yet did not stimulate human fibroblast proliferation [( 3H]thymidine incorporation). PC3 CM also increased cell numbers in human osteoblast but not fibroblast cell cultures. To determine whether the osteoblast-specific mitogenic activity could be attributed to known bone growth factors, specific assays for these growth factors were performed. PC3 CM contained 10 pg insulin-like growth factor (IGF) I, less than 2 pg IGF II, 54 pg basic fibroblast growth factor, and 16 pg transforming growth factor beta/microgram CM protein. None of these growth factors alone or in combination could account for the observed osteoblast-specific PC3 cell-derived mitogenic activity. Furthermore, when 5 micrograms/ml PC3 CM was tested in combination with maximally effective concentrations of either basic fibroblast growth factor, IGF I, IGF II, or transforming growth factor beta, it produced an additive effect suggesting that PC3 CM stimulates osteoblast proliferation by a mechanism independent of these bone mitogens. Biochemical characterization supported the hypothesis that the PC3 cell growth factor was unique from other growth factors. The PC3 growth factor did not bind to heparin and was resistant to acid as well as the reducing agent, dithiothreitol. Sephadex G-75 and fast protein liquid chromatography Mono S cation-exchange chromatography revealed the PC3-derived mitogen to be an Mr 26,000-30,000 basic protein. Therefore, we conclude that PC3 cells release a mitogen which exhibits higher specificity for human osteoblasts than human fibroblasts and is unique from other growth factors tested. Production of this mitogen by human prostatic carcinoma cells could play an etiological role in the intense osteoblast-specific stimulation that occurs at sites of bone metastases.

Impact of nitrogen flushing and oil choice on the progression of lipid oxidation in unwashed fried sliced potato crisps.

Unwashed, sliced, batch-fried potato crisps have a unique texture and are growing in popularity in the UK/EU premium snack food market. In this study, the storage stability of unwashed sliced (high surface starch) potatoes (crisps) fried in regular sunflower oil (SO) or in high oleic sunflower oil (HOSO) was compared over accelerated shelf life testing (45°C, 6 weeks); with and without nitrogen gas flushing. Primary oxidation products (lipid hydroperoxides) were measured with a ferrous oxidation-xylenol orange (FOX) assay and volatile secondary oxidation products (hexanal) were quantified by using solid phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC/MS). Results revealed that crisps fried in SO were the least stable. Flushing the stored crisps with nitrogen gas proved to be effective in slowing down the oxidation rate after frying with sunflower oil, significantly stabilizing the crisps. However, crisps fried in HOSO were the most stable, with the lowest rate of development of oxidation markers, and this has previously not been shown for crisps with a high free starch content.

Initial weight loss goals: have they changed and do they matter?

OBJECTIVE: Nearly 20 years ago, participants in behavioural weight loss programmes reported goals that greatly exceeded the amount of weight typically produced by these programmes. Whether having unrealistic weight loss goals impacts weight loss or attrition is unclear. The intent of the current study was to revisit current weight loss goals and examine whether goals impact outcomes. METHODS: Adults (N = 308, BMI = 33.7 ± 4.2 kg/m2) participated in a 12-month behavioural weight management programme and completed questionnaires about their goals. RESULTS: Participants' weight loss goal was 19.8 ± 7.9% of their body weight, and 90.4% selected a goal ≥10%. Weight goals were not associated with weight loss at 3 (p = 0.75) or 12 months (p = 0.47), or from 3 to 12 months (p = 0.55). Weight loss goals were not related to attrition at 3 (p = 0.91) or 12 months (p = 0.86). Participants believed that weight reduction would positively impact their health and psychosocial functioning. CONCLUSION: Weight loss goals have decreased, but still greatly exceed what can be expected by most. Unrealistic goals, however, had no impact on weight loss or attrition. These results question the utility of counseling people with obesity to set more realistic weight loss goals, which is typically practiced in behavioural weight management.

Quantitation of skeletal alkaline phosphatase isoenzyme activity in canine serum.

Pursuing the hypothesis that quantitation of skeletal alkaline phosphatase (ALP) activity in canine serum would provide an index of the rate of bone formation, we compared three methods for isoenzyme-specific identification of skeletal ALP activity in canine serum: heat inactivation, wheat germ agglutinin (WGA) precipitation, and concanavalin A (ConA) precipitation. ALP isoenzyme activities were extracted from canine bone, intestine, and liver, diluted into heat-inactivated canine serum (i.e., serum without ALP activity), and used as calibrators of ALP isoenzyme activities. Differential sensitivity to inhibition by 10 mM L-homoarginine was used to distinguish intestinal ALP activity from hepatic and skeletal ALP activities (i.e., 9, 80, and 72% inhibition, respectively). To allow resolution of skeletal ALP activity from hepatic ALP activity, we tested two established methods (heat inactivation and WGA precipitation) and a novel method, ConA precipitation. The organ-derived skeletal and hepatic ALP isoenzyme activities were used to compare these three methods with respect to linearity, isoenzyme separation, and precision. All three methods were linear, but the WGA and ConA methods afforded greater isoenzyme separation and precision. The relative extent of isoenzyme separation (i.e., the difference in percentage remaining skeletal and hepatic ALP isoenzyme activities) averaged 23, 40, and 47% remaining ALP activity for the heat, WGA, and ConA methods, respectively. However, when these methods were applied to the quantitation of skeletal ALP activity in sera from 10 young and 10 adult beagles, the WGA method was found to be unacceptable because most of the results fell outside the range of the WGA assay calibrators (i.e., greater than 100% skeletal ALP activity). The heat and ConA methods showed that the amount of skeletal ALP activity in the beagle sera decreased with age, both as ALP activity per liter and as percentage of total serum ALP activity (p less than 0.001 for each). Skeletal ALP activity levels determined by ConA were correlated with values determined by heat inactivation (r = 0.87, p less than 0.001) but not with WGA-determined levels (r = 0.26). Intestinal ALP activity was detected in only 1 of these 20 sera. We conclude that ConA precipitation can be used for quantitation of skeletal ALP activity in beagle serum.

Development of valid methods to measure insulin-like growth factors-I and -II in bone cell-conditioned medium.

A variety of human cells and biological fluids have been shown to produce or contain insulin-like growth factor (IGF)-specific binding proteins (BPs). The existence of these BPs in serum and conditioned medium of cell and organ cultures has complicated radioligand assays for measurement of IGFs. Various strategies have been proposed to avoid interference of BPs with these assays, including acid-ethanol precipitation of BPs and acid-gel filtration. Many of these procedures are time consuming, exhibit low recoveries, and do not completely eliminate BP artifacts. In this study we have investigated interference of inhibitory IGF-BP (In-IGF-BP) purified from bone cell-conditioned medium in an IGF-II RRA and IGF-I RIA and developed methods to neutralize In-IGF-BP artifacts in IGF assays. In the IGF-II RRA, purified In-IGF-BP competed for [125I]IGF-II binding to H-35 cells in a dose-dependent manner and, thus, increased the apparent value for IGF-II in the medium. Fifty percent inhibition of [125I]IGF-II binding to H-35 cells was seen at 12.2 and 5.7 ng/ml unlabeled IGF-II and IN-IGF-BP, respectively. In-IGF-BP also competed for [125I]IGF-I in the IGF-I RIA; however, the interference was much less in the IGF-I RIA compared to the IGF-II RRA. Fifty percent displacement of [125I]IGF-I binding was seen at 0.25 and 5 ng/ml unlabeled IGF-I and In-IGF-BP, respectively. Our approach to eliminate BP artifacts was as follows. We knew that In-IGF-BP showed comparatively equal binding affinities with both IGF-I and IGF-II, and binding of these ligands to cell receptors (IGF-II) and antibodies (IGF-I) was very specific (2% and 0.5% cross-reactivity for IGF-I and IGF-II, respectively). Therefore, in the IGF-I RIA we blocked the In-IGF-BP artifacts by adding an excess of IGF-II, and in the IGF-II RRA we blocked the In-IGF-BP artifacts by adding an excess of IGF-I. By incubating purified In-IGF-BP with different amounts of IGF-I, we found that 30-min preincubation of 5 ng In-IGF-BP with 10 ng IGF-I completely blocked BP artifacts in the IGF-II RRA. Similarly, preincubation of In-IGF-BP with IGF-II blocked BP artifacts in the IGF-I RIA.(ABSTRACT TRUNCATED AT 250 WORDS)

Absence of carbamazepine-induced hyponatremia among patients also given lithium.

Of 33 chronically psychotic patients in a state hospital, 17 received carbamazepine, 13 received carbamazepine and lithium, and three received carbamazepine and then the combination. There was a significant difference in serum sodium level between the patients receiving carbamazepine alone (mean +/- SD = 138.4 +/- 4.3 meq/liter) and those also receiving lithium (141.8 +/- 1.6 meq/liter). (A similar difference was seen for the patients who received the two treatments serially.) Age, sex, diagnosis, age at diagnosis, seizure disorder, antipsychotic drugs, and serum carbamazepine level did not explain this difference. The protection against hyponatremia provided by the carbamazepine-lithium combination occurred despite lithium's tendency to increase polyuria.

Neural organization of the masseter muscle in the pig.

The neural organization of the pig masseter, an architecturally and functionally compartmentalized muscle, was investigated by using dissection, glycogen depletion, evoked electromyography, and counts of axon numbers at various levels along the masseteric nerve. The masseteric nerve enters the muscle as two rostral branches, which also supply the zygomatico-mandibularis, and a more caudal main branch, which soon divides into four terminal nerves with variable distributions. Stimulation of filaments containing roughly 50 extrafusal motor axons resulted in glycogen depletion of 5-20% of the muscle fibers in very small subvolumes of the masseter; the affected subvolumes were delimited by perimysium. Electromyography after stimulation of various branches of the nerve confirmed the distributions deduced from anatomy and further indicated that axons do not branch between the rostral and main nerve branches but may occasionally do so among the more distal terminal branches of the main branch. The proximal trunk of the masseteric nerve contains about 3,500 myelinated fibers with a bimodal size distribution. Approximately 1,000 of the larger fibers were estimated to be extrafusal motor axons. Along the proximal trunk of the nerve, fibers were constantly rearranged; coupled with the observation that the locations of motor unit territories were usually not related to the position of the stimulated axons within the nerve, this suggests that the nerve trunk is not strictly ordered somatotopically.

The fibrinolytic potential of the normal primate following the generation of thrombin in vivo.

Parameters of the fibrinolytic system were studied in a primate model where the generation of thrombin was promoted in vivo. The procoagulant stimulus used was a combination of human factor Xa in combination with phosphatidylcholine/phosphatidylserine lipid vesicles (PCPS) as the source of coagulant active phospholipid. The dosage of each component was formulated to provide a gradation of thrombin generating potential assessed prior to in vivo study in an in vitro clotting assay. These ranged from 25.25-36.60 pMole/kg (factor Xa) and 18.85-56.30 nMole/kg (PCPS). In each case, the ratio of the dose of factor Xa/PCPS was maintained at 0.65 (pMole factor Xa/nMole PCPS). Individual dosage combinations producing recalcification clotting times in vitro of 15, 20, 25 and 30 s were used in detailed in vivo studies. Previous studies in dogs had confirmed the thrombin generating potential of factor Xa/PCPS infusions and demonstrated an associated activation of protein C and increased fibrinolytic activity. This has now been extensively characterized in the chimpanzee as follows: 10 min after the infusion of the highest dose (36.6 pMole factor Xa/56.3 nMole PCPS kg bodyweight), the level of circulating t-PA had risen to 900 ng/ml (antigen), 885 IU/ml (functional). Dosage was observed with the lowest dose of 12.25 pMole factor Xa and 18.85 nMole PCPS being associated with relatively minor increases in circulating t-PA activity. There were no changes in u-PA at any dosage during the full time course of the experimental period (90 min). Plasminogen activation was also apparent with alpha-2 antiplasmin levels falling to 30-40% of pre-infusion levels at the highest dosages.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of the biopsy site of the latissimus dorsi muscle for fiber typing.

The use of the latissimus dorsi muscle for cardiomyoplasty requires accurate assessment of the outcome of methods used to convert fast fibers to slow fibers. A knowledge of the normal distribution pattern of slow fibers within the latissimus dorsi is necessary for this endeavor. Fresh latissimus dorsi and teres major muscle tissues from seven pigs, one rabbit, two sheep, one monkey, and four dogs were studied with myosin adenosine triphosphatase staining. Fiber counts were made visually. With the exception of the rabbit, the distribution patterns were similar for all species: (1) intersegmentally--the number of slow fibers decreased steadily from the teres major to the anterior edge of the lateral segment; (2) intrasegmentally--slow fibers were more frequent in the deep layer than the superficial layer; and (3) intrasegmentally--the slow fibers tended to cluster in rosette formations around the neurovascular bundles. These patterns of distribution indicate the need for careful location of biopsies to ensure valid comparison of the amount of slow fibers in tissue before and after treatment.

Calcitonin acutely increases net 45Ca uptake and alters alkaline phosphatase specific activity in human osteosarcoma cells.

Although the primary skeletal action of exogenous calcitonin is to inhibit bone resorption, calcitonin also has effects on bone formation. In-vitro data indicate that the latter may include direct effects on bone cells of osteoblastic lineage. In the current studies, we examined the effects of calcitonin on cyclic adenosine monophosphate (cAMP) and PGE2 synthesis and 45Ca uptake in human osteosarcoma cells, specifically, TE-85 cells and subpopulations of SaOS-2 cells with low-, intermediate-, and high-steady-state levels of skeletal alkaline phosphatase (ALP) activity. Since previous in-vivo studies had shown that calcitonin could acutely decrease skeletal ALP activity in rat periosteal osteoblasts, we also measured the effects of calcitonin treatment on ALP specific activity. Neither salmon nor human calcitonin altered the net synthesis of cAMP or PGE2 by SaOS-2 cells, but human calcitonin gene-related peptide increased both (P < .001 and P < .005, respectively). Both salmon and human calcitonin had short-term effects to alter ALP activity in TE-85 and SaOS-2 cells. The effects were different in SaOS-2 subpopulations with different pretreatment ALP levels. Four hours of exposure to salmon calcitonin had dose-dependent, biphasic effects on ALP levels in SaOS-2 cells with intermediate pretreatment ALP levels, increasing ALP at doses between 0.16 and 1.6 nmol/L (P < .005) and decreasing ALP at higher concentrations (P < .05). Both salmon and human calcitonin, but not human calcitonin gene-related peptide, also had short-term effects to increase net 45Ca uptake by SaOS-2 cells; these effects were dose-dependent and long-lasting.(ABSTRACT TRUNCATED AT 250 WORDS)

Skeletal alkaline phosphatase specific activity is an index of the osteoblastic phenotype in subpopulations of the human osteosarcoma cell line SaOS-2.

During continuous culture with serial passage, the human osteosarcoma cell line SaOS-2 showed a time-dependent decrease in skeletal alkaline phosphatase (ALP) activity. Because this was indicative of heterogeneity, subpopulations of SaOS-2 cells were isolated from replicate low-density cultures. The subpopulations were less heterogeneous and more stable (with respect to ALP) than the parent population. ALP specific activity in the subpopulations ranged from 0.05 to 2.3 U/mg protein, and cytochemical analyses indicated multiple steady-state levels of ALP activity per cell. The amount of ALP activity in SaOS-2 subpopulations was proportional to collagen production ([3H]proline incorporation into collagenase-digestible protein; r = .84, P less than .005), and to parathyroid hormone (PTH)-linked synthesis of cyclic adenosine monophosphate (cAMP) (r = .88, P less than .01). From these data, we inferred that ALP activity in SaOS-2 cells can provide a useful index of the osteoblastic phenotype, and that ALP activity, collagen production, and PTH-linked adenylate cyclase were coordinately regulated in these osteoblast-like osteosarcoma cells (ie, selection of subpopulations for ALP activity coselected for collagen synthesis and PTH-linked synthesis of cAMP). Further comparative studies showed that micromolar fluoride concentrations stimulated cell proliferation ([3H]thymidine incorporation into DNA) in low-ALP SaOS-2 subpopulations, but not in high-ALP cells (P less than .001), and that this differential sensitivity to fluoride was associated with an inverse correlation between fluoride-sensitive acid phosphatase and ALP activities (r = -.91, P less than .001).

Mastication and maturity: a longitudinal study in pigs.

The electromyography of mastication was studied longitudinally in miniature pigs, and the effects of age and food type were assessed. Within-individual variation was large relative to between-individual variation. Duration of chewing strokes increased with age and with more resistant foods. The results are compared with data on human beings and other animals.