Nutritional secondary hyperparathyroidism in two cats: evaluation of bone mineral density with dual-energy X-ray absorptiometry and computed tomography.

Two three-month-old, intact female Abyssinian cats were presented with a history of lameness, constipation and ataxia. The cats had been fed a diet composed almost exclusively of meat. Both showed severe osteopenia and multiple pathological fractures on radiography. Following euthanasia of the more severely affected cat, postmortem examination revealed changes consistent with nutritional secondary hyperparathyroidism and fibrous osteodystrophy, such as cortical thinning, massive connective tissue invasion in the diaphysis of long bones, and hypertrophy of the chief cells in both parathyroid glands. After introducing a balanced commercial diet to the surviving cat, bone mineralisation improved from the baseline value, and at subsequent examinations at three, six and 22 weeks later, as indicated by bone mineral density measurements obtained by dual-energy X-ray absorptiometry and computed tomography.

Relationship between bone strength and dual-energy X-ray absorptiometry measurements in pigs.

Computed tomography and a 3-point bending test were performed on the metacarpal bones of adult production pigs to test the hypothesis that bone strength is strongly correlated with areal bone mineral density (BMD) in this population. The aim of the study was to subject material from adult production pigs grouped by BMD to 3-point bending, to test this hypothesis and determine any correlations. In all, 168 individual computed tomography scans and mechanical tests were performed on the collected material. For evaluation purposes, the material was divided into the categories low, medium, and high BMD (<1, 1 to 1.4, and >1.4 g/cm(2), respectively). The results showed a difference in the maximum load, in the stress at maximum load, and stiffness among each BMD group (P < 0.001) and in elastic modulus between the low BMD group and the 2 other groups (P < 0.001). A correlation between both intrinsic and extrinsic measures of bone strength and BMD was thus demonstrated. The projected change in each of the variables reported, for a 0.1 g/cm(2) alteration in BMD (within the BMD range evaluated in this study), is as follows: maximum load, 708 N; stress at maximum load, 50 N/mm(2); stiffness, 391.6 N/mm; and elastic modulus, 108 N/mm(2) (P < 0.001). The results confirm the relationship between BMD and bone strength and indicate that BMD screening can be used in fracture risk assessments in production pigs.

Dual-energy X-ray absorptiometry of the pig: Protocol development and evaluation.

As part of a prospective study in bone mineralisation in adult pigs it was necessary to establish guidelines and to define sites for bone mineral measurements. Particular requirements were that, the protocol should be suitable for a mass screening programme in both postmortem specimens and in live animals, and should deliver results of known reliability. Estimates of bone mineral content (BMC) and bone mineral density (BMD) in areas within the 4th metacarpal bone yielded coefficients of variation (CV) in the order of 7% for both regions and estimates in regions which included the entire metacarpal-phalangeal area yielded CV values in the order of 0.7% and 0.6% for BMC and BMD, respectively. A region of interest taken from the coccygeal vertebrae yielded coefficient of variation values of 3% and 2% for BMC and BMD, respectively. Accuracy of dual-energy X-ray absorptiometry (DXA) was estimated using a standard curve derived from BMC determined by ashing. There was a high correlation between mineral content determined by DXA and by ashing (R(2)=0.99, p<0.0001). The results suggest that the regions used in this study are suitable for use in large, mass screening, prospective studies.

Physiological responses to multiple speed treadmill walking for Syme vs. transtibial amputation--a case report.

PURPOSE: To date, there have been no longitudinal studies comparing walking at different levels of amputation. The objective of this study was to compare the self-selected walking velocity (SSWV) and selected physiologic variables during walking between a Syme and a later transtibial level of amputation for a single subject. Additional comparison was made between the SACH foot prosthesis and a dynamic response foot prosthesis. METHOD: A 35-year-old male with a traumatic Syme amputation later underwent elective transtibial amputation. SSWV and multiple speed treadmill walking tests (53.64, 67.05, 80.46, 93.87 and 107.28 m/min) were evaluated under three conditions (Syme prosthesis with SACH foot, transtibial prosthesis with SACH foot, and transtibial prosthesis with Flex-Foot). RESULTS: Walking with transtibial prosthesis showed minimal differences in oxygen consumption (0 - 5% reduction), heart rate response (0 - 1% reduction), or gait efficiency (0 - 5% improvement) across all speeds when compared with Syme prosthesis (both with SACH foot). However, the SSWV was 6 - 8% faster for the transtibial SACH foot. Walking with transtibial Flex-Foot required less cardiovascular demand than with transtibial SACH foot at higher speeds. CONCLUSIONS: In this case report, it seemed that transtibial amputation did not have adverse effects on selected physiological responses at a variety of walking speeds when compared to Syme amputation, and that the use of a dynamic response foot enhanced his gait performance. Further experimental studies involving more subjects with traumatic Syme and transtibial amputations are required to better understand the effect of these two levels of amputation on energy cost of walking.

Accuracy of diagnostic ultrasound for detection of cystic lesions: determination using receiver operating characteristic curve analysis of findings in phantom studies.

Anechoic, spherical cystic lesions are important findings on ultrasound examination. In polycystic renal disease of cats, they may be the only ultrasonographic sign of disease. This study assesses the accuracy of ultrasound, as used in a veterinary setting, for the detection of cysts. Using a spherical lesion ultrasound imaging phantom and 7.5- to 8-MHz linear array transducers, images of cysts of 2- and 4-mm diameter were created at various imaging depths from 0 to 6 cm. These were digitized and given to a panel of readers for interpretation. Area under receiver operating characteristic curves were used to evaluate test accuracy. It was shown that test accuracy was different at different imaging depths and differed with machines of differing price category. It is suggested that when setting standards for quality control in ultrasound, criteria used might be better related to imaging outcome studies rather than to aspects of machine specification.

New equations improve NIR prediction of body fat among high school wrestlers.

STUDY DESIGN: Methodologic study to derive prediction equations for percent body fat (%BF). OBJECTIVES: To develop valid regression equations using NIR to assess body composition among high school wrestlers. BACKGROUND: Clinicians need a portable, fast, and simple field method for assessing body composition among wrestlers. Near-infrared photospectrometry (NIR) meets these criteria, but its efficacy has been challenged. METHODS AND MEASURES: Subjects were 150 high school wrestlers from 2 Midwestern states with mean +/- SD age of 16.3 +/- 1.1 yrs, weight of 69.5 +/- 11.7 kg, and height of 174.4 +/- 7.0 cm. Relative body fatness (%BF) determined from hydrostatic weighing was the criterion measure, and NIR optical density (OD) measurements at multiple sites, plus height, weight, and body mass index (BMI) were the predictor variables. RESULTS: Four equations were developed with multiple R2s that varied from .530 to .693, root mean squared errors varied from 2.8% BF to 3.4% BF, and prediction errors varied from 2.9% BF to 3.1% BF. The best equation used OD measurements at the biceps, triceps, and thigh sites, BMI, and age. The root mean squared error and prediction error for all 4 equations were equal to or smaller than for a skinfold equation commonly used with wrestlers. CONCLUSION: The results substantiate the validity of NIR for predicting % BF among high school wrestlers. Cross-validation of these equations is warranted.

Effect of functional neuromuscular stimulation on postural related orthostatic stress in individuals with acute spinal cord injury.

The purpose of the study was to evaluate the cardiovascular responses of functional neuromuscular stimulation (FNS) on postural-related orthostatic stress in individuals with acute spinal cord injury. Two tetraplegics and three paraplegics participated in this study. A repeated measure design was used in which subjects underwent two graded-tilt table (0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees) orthostatic stress tests with and without FNS (randomized treatment order) of the knee extensors and foot plantar flexors. Successive one-minute digital readings of heart rate (HR) and blood pressure were obtained with an electronic pulse oximeter and automated blood pressure monitor, respectively. Analysis of covariance (ANCOVA) revealed significant test position (tilt angle) and treatment condition (with or without FNS) main effects, but no significant interactions. Between-treatment pairwise contrasts showed that systolic blood pressure was lower without FNS for 15 degrees, 30 degrees, 45 degrees g, and 60 degrees of tilt, while diastolic blood pressure was lower without FNS at 30 degrees and 45 degrees of tilt. In contrast, HR showed a progressive rise with increasing tilt angle. Functional neuromuscular stimulation may be an important treatment adjunct to minimize cardiovascular changes during postural orthostatic stress in individuals with acute spinal cord injury.

Physiological measurements of walking and running in people with transtibial amputations with 3 different prostheses.

STUDY DESIGN: A 3-factor (foot type, speed, and mode of ambulation) repeated-measures experimental design was used. OBJECTIVES: To compare the differences in energy expenditure, gait efficiency, and relative exercise intensity in persons with transtibial amputations with various prostheses. BACKGROUND: There is a need for improved prosthetic designs to accommodate physically active persons with lower-extremity amputations. METHODS AND MEASURES: We used progressive speeds of treadmill walking (53.64, 67.05, 80.46, 93.87, and 107.28 m/min) and running (120.69, 134.1, and 147.51 m/min) with 3 different types of prostheses: the Solid Ankle Cushion Heel (SACH) foot, the Flex-Foot (FF), and the Re-Flex Vertical Shock Pylon (VSP) prosthesis. Five physically active men with unilateral transtibial amputations served as subjects (aged 31.6 +/- 4.28 years). RESULTS: The following statistically significant differences (improvements) between the Re-Flex VSP versus the FF and the SACH foot were found. Energy cost: walking (5%), running (11%); gait efficiency: walking (6%), running (9%); relative exercise intensity: walking (4%), running (5%). However, we found no significant differences between the FF and the SACH. CONCLUSIONS: The Re-Flex VSP appears to have a positive effect on energy cost, efficiency, and relative exercise intensity compared with the other prosthetic foot types during walking and running.

Altered insulin resistance is associated with increased dietary weight loss in obese children.

To determine the relationship between insulin resistance and weight loss in early obesity, we used the euglycemic, hyperinsulinemic clamp to study the effect of a 14-day weight reduction diet in 10 prepubertal and early pubertal obese children (age, 10.1 +/- 1.6 years) on insulin sensitivity. Body weight decreased from 73.7 +/- 6.0 kg to 69.1 +/- 5.8 kg (p < 0.01). Insulin sensitivity before weight reduction negatively correlated with the amount of weight loss during diet (r = -0.8, p < 0.005). Weight loss also positively correlated with height standard deviation score (r = 0.9, p < 0.005). Mean insulin sensitivity increased from 0.068 +/- 0.01 (nmol kg-1 min-1)/(pmol l-1) to 0.096 +/- 0.030 (nmol kg-1 min-1)/(pmol l-1) (p < 0.05, one-tailed test). These results indicate that weight reduction decreases insulin resistance in childhood obesity. The inverse relationship between insulin sensitivity and weight loss during calorie, restriction in these subjects suggests that insulin resistance may enhance weight loss during calorie restriction.

Validity of near infrared body composition analysis in children and adolescents.

The purpose of this study was to evaluate the validity and reliability of the Futrex 5000A near infrared (NIR) spectrophotometer for the assessment of body composition in children and adolescents. Forty-eight subjects (24 boys and 24 girls) with a mean age of 12.7 +/- 2.7 yr underwent three methods of body composition testing: NIR, densitometry by hydrostatic weighing (HYDRO), and skinfold anthropometry (SKF). Percent body fat (%BF) and fat free mass (FFM) derived from the Lohman's age-adjusted Siri equation served as the criterion. Within session test-retest reliability was determined for the NIR device for all subjects and between-week reliability was evaluated for all test methods in 14 subjects. Based on the excellent within- and between-session reliability (ICC ranged from 0.907-0.999), the system offers the potential of obtaining longitudinal data in growth and development studies. However, the significant mean differences, moderate correlations with the criterion (r = 0.62-0.71) and inflated standard errors of estimate (SEE = 4.9-5.5% BF, 2.2-2.9 kg FFM) and total prediction errors (TE = 5.5-8.0% BF, 2.7-3.7 kg FFM) indicate that refinement of prediction equations is needed to establish the measurement validity. Continued research with expanded populations is needed to further demonstrate and evaluate the utility of this device.

Cross-validation of the Slaughter skinfold equations for children and adolescents.

Prior to sexual maturation, children and adolescents have more water and less bone mineral content than adults, resulting in less dense fat-free body mass (FFM). This suggests that previously established adult skinfold/density equations are inappropriate for use with children and adolescents for the prediction of body fatness (%BF) and FFM. To overcome this problem, Slaughter and colleagues have introduced new skinfold (SKF) equations that take into account the changing density of FFM in children and adolescents as they mature. The purpose of our study was to cross-validate a select set of the Slaughter SKF equations by comparing them with a criterion measurement (Lohman's Siri age-adjusted body density equation) in 122 subjects ranging in sexual maturation from pre- to post-pubescent and ranging in age from 8-17. Our cross-validation found very high intraclass (reliability) correlations (ICCs = 0.98-0.99) and high validity correlations (rs = 0.79-0.99). The standard errors of the estimate for %BF ranged from 3.5-4.6% and total errors for %BF ranged from 3.6-4.6%. The Slaughter equation using tricep and calf SKF for females was significantly different (P < 0.05) from the criterion measure in its prediction of %BF. In males, there was an interaction between the SKF equation and subject maturation level. The data indicate that the Slaughter SKF equations hold promise for estimating body composition in children and adolescents but are still in need of refinement.

Cross-validation of bioelectrical impedance analysis of body composition in children and adolescents.

BACKGROUND AND PURPOSE: The reliability and validity of measurements obtained with two bioelectrical impedance analyzers (BIAs), an RJL Systems model BIA-103 and a Berkeley Medical Research BMR-2000, were investigated using the manufacturers' prediction equations for the assessment of fat-free mass (FFM) (in kilograms) in children and adolescents. SUBJECTS: Forty-seven healthy children and adolescents (23 male, 24 female), ranging in age from 8 to 20 years (mean = 12.1, SD = 2.3), participated. METHODS: In the context of a repeated-measures design, the data were analyzed according to gender and maturation (Tanner staging). Hydrostatic weighing (HYDRO) and Lohman's Siri age-adjusted body density prediction equation served as the criteria for validating the BIA-obtained measurements. RESULTS: High intraclass correlation coefficients (ICC > or = .987) demonstrated good test-retest (between-week) measurement reliability for HYDRO and both BIA methods. Between-method (HYDRO versus BIA) correlation coefficients were high for both boys and girls (r > or = .97). The standard errors of estimate (SEEs) for FFM were slightly larger for boys than for girls and were consistently smaller for the RJL system than for the BMR system (RJL SEE = 1.8 kg for boys, 1.3 kg for girls; BMR SEE = 2.4 kg for boys, 1.9 kg for girls). The coefficients of determination were high for both BIA methods (r2 > or = .929). Total prediction errors (TEs) for FFM showed similar between-method trends (RJL TE = 2.1 kg for boys, 1.5 kg for girls; BMR TE = 4.4 kg for boys, 1.9 kg for girls). DISCUSSION AND CONCLUSION: This study demonstrated that the RJL BIA with the manufacturer's prediction equations can be used to reliably and accurately assess FFM in 8- to 20-year-old children and adolescents. The prediction of FFM by the BMR system was acceptable for girls, but significant overprediction of FFM for boys was noted.

Cardiorespiratory responses of healthy subjects to calisthenics performed on land versus in water.

This study evaluated the oxygen consumption (VO2) and heart rate response curves for standardized upper- and lower-extremity exercise on land and in water. Forty healthy subjects performed one upper-extremity and one lower-extremity exercise at three selected cadences on land and in water. Steady-state heart rate was determined by electrocardiographic radiotelemetry and expressed as a percentage of age-predicted maximal heart rate (% APMHR). Percentage of age-predicted maximal heart rate was used as the criterion measure of relative exercise intensity. Oxygen consumption was determined by the open-circuit method. Results indicated systematic increases in VO2 from 2 to 9 metabolic equivalents (METs) (1 MET = 3.5 mL O2.kg-1.min-1) and % APMHR from 45% to 73% with increased cadence. The VO2 responses were highest during water exercise, whereas % APMHR was greater during land exercise. Based on the magnitude of the responses, water calisthenics appear to be of sufficient intensity to elicit training adaptations. Training studies are needed to document these changes.

Interrater reliability of hand-held dynamometry: effects of rater gender, body weight, and grip strength.

Clinicians and authors of previous publications have not reached agreement on the interrater reliability of dynametric strength testing. This study investigates the effects of gender, body weight, and grip strength on the reliability of hand-held dynametric strength measurements. Ten male and 10 female raters tested five muscle groups on the same two subjects (one male and one female) with a Chatillon Series D hand-held, spring-scale dynamometer. Both the raters and the test subjects were blinded to the dynametric output readings throughout the testing. Interrater reliability was good for all tests except for female raters when testing the male subjects' stronger muscle groups. Standard deviations were 61% and 50% greater for female vs. male raters for elbow flexors and knee extensors, respectively. Female raters' body weight had a significant correlation with torque when testing male subjects' wrist extensors, ankle dorsiflexors, and knee extensors (r > 0.64). Likewise, female raters' grip strength significantly correlated with torque when testing males' wrist extensors and elbow flexors (r >/= 0.71). The results indicate that gender, body weight, and grip strength affect a rater's ability to stabilize a hand-held dynamometer and could influence reliability when testing stronger muscle groups. J Orthop Sports Phys Ther 1992;16(2):74-81.

Body composition of collegiate football players: bioelectrical impedance and skinfolds compared to hydrostatic weighing.

The need for simple, valid techniques of body composition assessment among athletes is a growing concern of the physical therapist. This paper reports on several common methods applied to university football players. Body composition analysis was conducted on 28 Division IA football players using three different bioelectrical impedance analysis (BIA) systems, skinfolds (SF), and hydrostatic weighing (HYDRO). Correlations for all methods with HYDRO were high (>.88), but BIA significantly overpredicted body fatness. In contrast, three SF equations showed small differences with HYDRO and reasonable measurement error. Clinicians should exercise caution when using BIA based on the existing manufacturers' equations with athletic populations. Adjustments to BIA regression equations by including modifying or anthropometric variables could enhance the predictive accuracy of these methods with lean, athletic males. J Orthop Sports Phys Ther 1992;15(4):187-192.

Effects of an individualized treadmill exercise training program on cardiovascular fitness of adults with mental retardation.

This study was supported in part by a research fund provided by Woodward State Hospital School, Woodward, IA. Although our society has recognized the need of the "normal" population for physical exercise and wellness, little attention has been given to the physical fitness needs of persons with mental retardation. Physical therapy intervention for these individuals is generally restricted to medical problems, usually of orthopaedic or neuromuscular origin, with little emphasis on cardiovascular function. The purpose of this study was to evaluate the effects of an individualized treadmill exercise training (TET) program on the cardiovascular fitness (CVF) of six adults with mental retardation in an institutional setting. A multiple group by time cross-over design was used. The subjects were randomly assigned to either an experimental group (N = 3) or control group (N = 3) after an 8-week orientation period. After completion of baseline measurements, the experimental group underwent 12 weeks (Period I) of progressive TET exercise five times weekly, while the control group received no structured exercise training during this period. Treadmill graded exercise testing was performed every 4 weeks on both groups. After completion of Period I, the control group was put on a TET program similar to the one performed by the experimental group, and the experimental group underwent a maintenance TET program, with exercise two times weekly. Results indicated reduced heart rate (HR) for standardized submaximal treadmill workloads and significantly increased estimated peak oxygen uptake (VO2) (38%) and heart rate (10%) subsequent to 12 weeks of TET. Low frequency TET was effective in maintaining CVF. Treadmill exercise training was found to be a safe exercise modality, and compliance to TET was good among all subjects. In conclusion, TET appears to be an effective modality in improving and maintaining CVF of adults with mental retardation in an institutional setting. Additional research with more subjects is recommended to confirm these results. J Orthop Sports Phys Ther 1992;16(5):220-228.

Wrestlers' minimal weight: anthropometry, bioimpedance, and hydrostatic weighing compared.

The need for accurate assessment of minimal wrestling weight among interscholastic wrestlers has been well documented. Previous research has demonstrated the validity of anthropometric methods for this purpose, but little research has examined the validity of bioelectrical impedance (BIA) measurements. Comparisons between BIA systems has received limited attention. With these two objectives, we compared the prediction of minimal weight (MW) among 57 interscholastic wrestlers using three anthropometric methods (skinfolds (SF) and two skeletal dimensions equations) and three BIA systems (Berkeley Medical Research (BMR), RJL, and Valhalla (VAL]. All methods showed high correlations (r values greater than 0.92) with hydrostatic weighting (HW) and between methods (r values greater than 0.90). The standard errors of estimate (SEE) were relatively small for all methods, especially for SF and the three BIA systems (SEE less than 0.70 kg). The total errors of prediction (E) for RJL and VAL (E = 4.4 and 3.9 kg) were significantly larger than observed nonsignificant BMR and SF values (E = 2.3 and 1.8 kg, respectively). Significant mean differences were observed between HW, RJL, VAL, and the two skeletal dimensions equations, but nonsignificant differences were observed between HW, BMR, and SF. BMR differed significantly from the RJL and VAL systems. The results suggest that RJL and VAL have potential application for this subpopulation. Prediction equation refinement with the addition of selected anthropometric measurement or moderating variables may enhance their utility. However, within the scope of our study, SF and BMR BIA appear to be the most valid methods for determining MW in interscholastic wrestlers.

Energy cost, exercise intensity, and gait efficiency of standard versus rocker-bottom axillary crutch walking.

The purpose of this study was to investigate differences in selected biomechanical and physiological measurements and subjective preferences for ambulation with the standard single-tip axillary crutch versus the rocker-bottom-type axillary crutch. Self-selected walking velocities (S-SWVs) and stride length for each crutch type were determined for a two-point, non-weight-bearing, swing-through gait in 24 healthy volunteers. Relative exercise intensity, oxygen uptake (VO2), and gait efficiency were assessed for each crutch type at both S-SWVs. Subjects negotiated two architectural barriers (stairs and ramp) and completed a subjective questionnaire concerning crutch preferences. Walking with either crutch type resulted in slower S-SWVs, greater VO2, higher relative exercise intensity, and reduced gait efficiency compared with values for normal unassisted ambulation. An analysis of variance for these variables revealed nonsignificant between-crutch differences. Based on the subjective data, a preference for the standard single-tip crutch was evident. Within the scope of the study, the results supported no apparent advantage relative to energy expenditure to using the rocker-bottom crutch.

Validity and reliability testing of the Scoliometer.

This study was designed to evaluate the Scoliometer, an instrument that measures axial trunk rotation in individuals with scoliosis. The objectives included determining 1) the Scoliometer's screening capability and validity and 2) the intrarater and interrater reliability of Scoliometer measurements. Scoliometer measurements made by two raters on 65 persons with idiopathic scoliosis were correlated with radiographic assessment of vertebral (pedicle) rotation and lateral curvature (Cobb method). Correlation ranged from .32 to .46 with pedicle rotation and from .46 to .54 with the Cobb angle. Frequency analysis revealed relatively good specificity, sensitivity, and predictive capability of the Scoliometer. Intrarater and interrater reliability coefficients were high (r = .86-.97). These results indicate good measurement reproducibility. The less-than-optimal between-method correlation coefficients suggest that the validity of Scoliometer measurements is not sufficient to use this method alone for determining patient diagnosis and management. Based on the positive-frequency analysis, however, the use of this tool as a screening device would be appropriate.