Common aetiology for diverse language skills in 41/2-year-old twins

Multivariate genetic analysis was used to examine the genetic and environmental aetiology of the interrelationships of diverse linguistic skills. This study used data from a large sample of 4 1/2 year-old twins who were tested on measures assessing articulation, phonology, grammar, vocabulary, and verbal memory. Phenotypic analysis suggested two latent factors: articulation (2 measures) and general language (the remaining 7), and a genetic model incorporating these factors provided a good fit to the data. Almost all genetic and shared environmental influences on the 9 measures acted through the two latent factors. There was also substantial aetiological overlap between the two latent factors, with a genetic correlation of 0·64 and shared environment correlation of 1·00. We conclude that to a large extent, the same genetic and environmental factors underlie the development of individual differences in a wide range of linguistic skills

From twitch to tetanus for human muscle - experimental data and model predictions for m. triceps surae

In models describing the excitation of muscle by the central nervous system, it is often assumed that excitation during a tetanic contraction can be obtained by the linear summation of responses to individual stimuli, from which the active state of the muscle is calculated. We investigate here the extent to which such a model describes the excitation of human muscle in vivo. For this purpose, experiments were performed on the calf muscles of four healthy subjects. Values of parameters in the model describing the behaviour of the contractile element (CE) and the series elastic element (SEE) of this muscle group were derived on the basis of a set of isokinetic release contractions performed on a special-purpose dynamometer as well as on the basis of morphological data. Parameter values describing the excitation of the calf muscles were optimized such that the model correctly predicted plantar flexion moment histories in an isometric twitch, elicited by stimulation of the tibial nerve. For all subjects, the model using these muscle parameters was able to make reasonable predictions of isometric moment histories at higher stimulation frequencies. These results suggest that the linear summation of responses to individual stimuli can indeed give an adequate description of the process of human muscle excitation in vivo

The anatomical limits of the posterior vaginal vault toward its use as route for intra-abdominal procedures

Background The use of natural openings for abdominal surgery started at the beginning of the 21th century. A trans-Douglas endoscopic device has been designed to perform most of the intra-abdominal operations in women through the pouch of Douglas. The posterior vaginal vault is limited in size and could be damaged by an oversized instrument. This study investigates the optimal dimensions of the instrument by measuring the limiting factor in the passage. Methods In ten female embalmed bodies the transversal and sagittal diameter of the fornix posterior vaginalis was measured by two observers. The pouch of Douglas was filled to its maximal capacity with mouldable latex through an open abdomen. By internal vaginal examination the connective tissue borders of the fornix posterior were palpated and the impression in the cast was measured. The mean value of these two diameters was evaluated in this study. The level of agreement between the observers was calculated. Results The mean fornix posterior diameter was 2.6 cm (standard deviation, SD 0.5 cm) with a range of 2.0-3.4 cm. The mean difference between the two observers of all measurements was 0.08 cm (not significant). Both observers had an acceptable intraobserver variation. The interobserver agreement was excellent. Conclusion Instruments with dimensions within the measured limits can be used safely for intra-abdominal operations via the natural orifice of the vagina

Dynamic spasticity of plantar flexor muscles in cerebral palsy gait

Objective: To quantify dynamic spasticity, i.e. the coupling between muscle-tendon stretch velocity and muscle activity during gait, of the gastrocnemius and soleus muscles in children with spastic cerebral palsy. Design: Prospective, cross-sectional study. Subjects: Seventeen ambulatory children with cerebral palsy with spastic calf muscles, and H matched typically developing children. Methods: The children walked at 3 different speeds. Threedimensional kinematic and electromyographic data were collected. Muscle-tendon velocities of the gastrocnemius medialis and soleus were calculated using musculoskeletal modelling. Results: In typically developing children, muscles were stretched fast in swing without subsequent muscle activity, while spastic muscles were stretched more slowly for the same walking speed, followed by an increase in muscle activity. The mean ratio between peak activity and peak stretch velocity in swing was approximately 4 times higher in spastic muscles, and increased with walking speed. In stance, the stretch of muscles in typically developing children was followed by an increase in muscle activity. Spastic muscles were stretched fast in loading response, but since muscle activity was already built up in swing, no clear dynamic spasticity effect was present. Conclusion: Spastic calf muscles showed increased coupling between muscle-tendon stretch velocity and muscle activity, especially during the swing phase of gait. © 2010 Foundation of Rehabilitation Information

План заходів із збереження та розвитку Національного дендрологічного парку «Софіївка» Національної академії наук

OBJECTIVES: Asians have a smaller muscle mass and a larger fat mass at the same body mass index (BMI) than most other ethnic groups. Due to a resulting higher cardiometabolic risk, the BMI cut-offs for overweight and obesity were lowered for adults. For Asian children universal criteria apply. The objectives of this study were to determine the normal BMI distribution and assess the BMI class distribution in a reference cohort of affluent South Asian children born before the obesity epidemic and to assess the influence of the obesity epidemic on the distributions.METHODS: Historical cohort study with 4350 measurements of height and weight of two cohorts (born 1974-1976 and 1991-1993) of Surinamese South Asian children living in The Netherlands, analysed with WHO Child Growth References and International Obesity Task Force (IOTF) BMI cut-offs.RESULTS:The reference cohort 1974-1976 was significantly lighter (BMI Z-score=-0.63; 95% CI -0.69 to -0.58) and more variable (SD=1.19) than WHO reference. Total thinness prevalence was exceptionally high, both in cohort 1974-1976 (WHO 38.3%; IOTF 36.4%) and 1991-1993 (WHO 23.6%; IOTF 23.9%). Overweight and obesity prevalences were low in the reference cohort (WHO respectively 6.0% and 2.1%; IOTF 5.3%, 0.9%), but much higher in cohort 1991-1993 (WHO 13.6%, 9.1%; IOTF 11.7%, 6.0%).CONCLUSIONS: The low mean BMI Z-score and high prevalence of thinness are likely expressions of the characteristic body composition of South Asians. Universal BMI cut-offs should be applied carefully in South Asian populations as thinness prevalence is likely to be overestimated and obesity underestimated. The development of ethnic specific cut-offs is recommended

Reading and Generalist Genes

Twin-study research suggests that many (but not all) of the same genes contribute to genetic influence on diverse learning abilities and disabilities, a hypothesis called generalist genes. This generalist genes hypothesis was tested using a set of 10 DNA markers (single nucleotide polymorphisms [SNPs]) found to be associated with early reading ability in a study of 4,258 7-year-old children that screened 100,000 SNPs. Using the same sample, we show that this early reading SNP set also correlates with other aspects of literacy, components of mathematics, and more general cognitive abilities. These results provide support for the generalist genes hypothesis. Although the effect size of the current SNP set is small, such SNP sets could eventually be used to predict genetic risk for learning disabilities as well as to prescribe genetically tailored intervention and prevention programs

Interial sensing in a hand held dynamometer

Two methods for kinematic sensing in a hand-held dynamometer using accelerometers and gyroscopes are presented. The first method integrates the angular velocity signal from the gyroscope, after calibration of gyroscope offset and joint angle from a static period immediately preceding each measurement. The second method estimates tangential and radial accelerations, enabling the estimation of the gravity components in the accelerometer signals under dynamic conditions, and thus angle reconstruction. The second method appeared to perform best in preliminary test

About Bites and Steps : aetiology and prevention of incisional hernia

Experimental and clinical studies on incisional hernia formation and prevention. In this thesis the effect of the small bite suture technique is evaluated. Novel concepts like the abdominal wall simulator was presente