Body borne loads impact walk-to-run and running biomechanics.

The purpose of this study was to perform a biomechanics-based assessment of body borne load during the walk-to-run transition and steady-state running because historical research has limited load carriage assessment to prolonged walking. Fifteen male military personnel had trunk and lower limb biomechanics examined during these locomotor tasks with three different load configurations (light, ∼6 kg, medium, ∼20 kg, and heavy, ∼40 kg). Subject-based means of the dependent variables were submitted to repeated measures ANOVA to test the effects of load configuration. During the walk-to-run transition, the hip decreased (P=0.001) and knee increased (P=0.004) their contribution to joint power with the addition of load. Additionally, greater peak trunk (P=0.001), hip (P=0.001), and knee flexion (P<0.001) moments and trunk flexion (P<0.001) angle, and reduced hip (P=0.001) and knee flexion (P=0.001) posture were evident during the loaded walk-to-run transition. Body borne load had no significant effect (P>0.05) on distribution of lower limb joint power during steady-state running, but increased peak trunk (P<0.001), hip (P=0.001), and knee (P=0.001) flexion moments, and trunk flexion (P<0.001) posture were evident. During the walk-to-run transition the load carrier may move joint power production distally down the kinetic chain and adopt biomechanical profiles to maintain performance of the task. The load carrier, however, may not adopt lower limb kinematic adaptations necessary to shift joint power distribution during steady-state running, despite exhibiting potentially detrimental larger lower limb joint loads. As such, further study appears needed to determine how load carriage impairs maximal locomotor performance.

Growth allometry of the mandibles of giant transgenic mice: an analysis based on the finite-element scaling method.

Transgenic mice genetically engineered to produce increased levels of growth hormones, accelerated somatic growth, and larger terminal sizes [Palmiter et al., 1982, 1983] offer an intriguing model with which to investigate the genetic and developmental control of skeletal proportions. In this study, form differences in the mandible between giant transgenic mice (MT-rGH) and their normal litter-mate controls are examined using data generated by finite-element scaling analysis (FESA). Finite-element scaling analysis is a tensor based method developed to study morphological differences between forms. The method uses landmark data to provide measures of size and shape differences local to those landmarks of mandibular size and shape differences for 18 landmarks were compared between the two mouse samples. Bivariate and multivariate analyses were completed to ascertain 1) whether the mandible of larger transgenic mice differed significantly from normal controls, and 2) if observed proportion change resulted from the general allometric affects of overall mandibular size increase. Comparisons of local size and shape differences against a measure of total size difference reveal similar trajectories of growth allometry, indicating that proportion differences between adult control and transgenic mice result from ontogenic scaling.

Cranial growth and growth dimorphism in Ateles geoffroyi.

With the exception of the work of Schultz (1960), cranial growth in Ateles is not well documented. This paper describes the results of a detailed quantitative study of cranial ontogeny in male and female Ateles geoffroyi. Using Euclidean Distance Matrix Analysis (EDMA), local areas of form change due to growth within spider monkey crania are identified. We found substantial change local to the zygomatic region in the face, identified mediolaterally directed changes in the palate, detected relatively larger amounts of change local to the anterior neurocranium compared to the posterior neurocranium, and demonstrate a greater amount of basicranial growth along a mediolateral axis than previously reported. Cranial sexual dimorphism is also examined. A. geoffroyi is noted for being monomorphic, and we found a general similarity between male and female cranial forms at all developmental ages. However, differences in overall cranial size between the sexes were found in the oldest subadult age group but not between male and female adults. This difference suggests that A. geoffroyi females attain their adult cranial form slightly before males and implies a pattern of earlier onset of female maturity relative to males.

Experiments of nature: premature unicoronal cranial synostosis in mantled howler monkeys (Alouatta palliata).

In 1960 Adolph Schultz described several cases of plagiocephaly in a collection of mantled howler monkeys (Alouatta palliata) from the forests of Central America. Since then several more specimens have been described. These individuals make up one of the largest samples of nonhuman primates that are affected by craniosynostosis. In this study, we used finite element scaling analysis (FESA) to quantify morphologic differences between adult normal (N = 19) and plagiocephalic female howler monkeys (N = 4). FESA utilizes three dimensional coordinate data to provide detailed information on size and shape differences local to biologic landmarks. The relatively large number of plagiocephalic howler monkeys provides a natural means for examining hypotheses concerning patterns of dysmorphology associated with plagiocephaly. Comparison of our results to observations from the clinical literature reveals similarities in neurocranial and facial morphology among plagiocephalic humans and howler monkeys, but the direction and magnitude of local form differences between howler monkeys and humans indicate species-specific responses to sutural constraint. Few cases of craniosynostosis in nonhuman primates are known. The number of plagiocephalic howler monkeys suggests these monkeys may be particularly susceptible to some defect that leads to premature suture closure. If this is the case, then howler monkeys may be a good model to study the cause(s) of craniosynostosis.

Cranial growth in the squirrel monkey (Saimiri sciureus): a quantitative analysis using three dimensional coordinate data.

Improvements in data gathering technology have made it possible to quickly and accurately digitize large numbers of objects. The three dimensional coordinates of 44 homologous landmarks were obtained from a sample of 104 squirrel monkey (Saimiri sciureus) crania. After sorting by sex, the crania were assigned to one of four dental age groups. Two quantitative methods, Euclidean distance matrix analysis (EDMA) and finite element scaling analysis (FESA), were used to study craniofacial form change during growth within each sex. Form differences between the sexes at each developmental age were also examined. Both sexes show a small amount of cranial growth overall; however, there are areas of substantial local growth. These areas include the anterior neurocranium and basicranium, the basioccipital, and the anterior palate. Sexual dimorphism in the craniofacial complex is minimal. The most dimorphic regions are the orbitonasal portion of the lower face, the cranial base, and the palate.

Morphometric analysis of craniofacial growth in Cebus apella.

The present study was undertaken to provide a quantitative description of craniofacial growth in Cebus apella in three dimensions. Landmarks from a cross-sectional sample of sexed and dentally aged crania were collected using a 3Space digitizer. Two methods of three-dimensional form analysis, euclidian distance matrix analysis (EDMA) and finite-element scaling analysis (FESA), were used to investigate growth changes in the cranium. Male and female growth was examined by comparing the youngest male mean form to all other age/sex specific mean forms. In addition, form differences between the sexes were studied by comparing male and female mean forms at each age. The cranium was divided into four regions for analysis: muzzle, upper face, neurocranium, and basicranium. Growth changes within each region were examined. In the muzzle and neurocranium, most growth occurs along the anteroposterior axis. Growth around pterion and the lower orbital rim is prominent within the upper face. The basicranium shows a surprisingly large amount of form change with growth. This form change is due to the mediolateral expansion of the basioccipital, and to the posterior migration and inferior rotation of basion. Males and females have similar growth patterns, but males tend to be larger than females in nearly all dimensions at every developmental age except the youngest. Evidence suggests that craniofacial sexual dimorphism is primarily due to males growing faster than females for approximately the same amount of time.

Mycoplasma pneumoniae infections in children.

Details are given of all serologically confirmed Mycoplasma pneumoniae infections in children referred to Bristol hospitals during an epidemic lasting 18 months. 44 children, many below school age, had lower respiratory infections. The majority had cough and malaise which had failed to respond to antibiotics given before referral. Chest x-rays showed no pathognomonic features: segmental or patchy consolidation was common; 3 cases of lobar consolidation. Cold agglutinins were raised in 9 out of 12 cases. In the majority of cases the total leucocyte count was normal and the absolute neutrophil count raised. Mean duration of symptoms was 4.2 weeks (range 1-16). Treatment with erythromycin or tetracycline appeared to have little effect in most cases. Seven nonrespiratory manifestations were seen in 6 children. These were meningitis (2 cases), Stevens-Johnson syndrome (4 cases, 1 case complicated by toxic epidermal necrolysis), and acute haemolytic anaemia (1 case).

Clinical and biochemical studies in Engelmann's disease (progressive diaphyseal dysplasia).

The clinical and biochemical features of four adults with Engelmann's disease (Camurati-Engelmann disease; progressive diaphyseal dysplasia) are presented. One young patient, with a particularly severe form of the disease, is discussed in detail. Biochemical abnormalities were found in three of the patients. In two of them, one with localized hyperostosis and one with generalized bone disease, the only changes were an increase in the plasma alkaline phosphatase and urinary total hydroxyproline excretion. The most severely affected patients, who had had progressive and generalized bone disease from age two and a half years, also had persistent hypocalcaemia and hyperphosphataemia, a positive calcium balance, and a very low urine calcium excretion. It is suggested that some patients with Engelmann's disease may have a previously unrecognized metabolic disorder associated with increased retention of calcium and excessive bone formation. The possible role of abnormal phosphate metabolism in this increased formation of bone, and the relationship of Engelmann's disease to other hyperostoses, are discussed.

Absorption of hexachlorophane from dusting powder on newborn infant's skin.

In a maternity hospital in which the umbilicus and trunk of healthy newborn infants were treated with 0.33% hexachlorophane dusting powder, the hexachlorophane content of blood was measured in mothers before delivery, in infants' umbilical samples at birth, and at 8 days of age in capillary blood samples. One mother and her baby had rather high blood concentrations of hexachlorophane, probably derived from a toilet preparation used before admission to hospital. Hexachlorophane was absent or barely detectable in the other mothers' blood and in the infants' umbilical blood. The hexachlorophane concentrations in the blood of 8-day-old infants ranged from nil to 0.166 mug./ml. (mean 0.066 mug./ml.). These were much less than the concentrations reported to be toxic in animals.In a previous trial now reported here, a dusting powder containing chlorhexidine instead of hexachlorophane was found to delay the separation of the umbilical cord.