Normal values of balance tests in women aged 20-80

OBJECTIVES: To determine normal values for four commonly used clinical functional balance tests from community-dwelling women aged 20 to 80 and to identify any significant decline due to aging. DESIGN: A cross-sectional study was undertaken to provide normative values for four clinical balance tests across 6 decade cohorts. SETTING: The Betty Byrne-Henderson Center for Women and Aging, Royal Womens' Hospital, Brisbane, Australia. PARTICIPANTS: Four hundred fifty-six community-dwelling, independently ambulant women with no obvious neurological or musculoskeletal-related disability, aged 20 to 80, were randomly recruited from a large metropolitan region. MEASUREMENTS: The clinical balance measures/tests were the Timed Up and Go test, step test, Functional Reach test, and lateral reach test. Multivariate analysis was used to test the effect for age, height, and activity level. RESULTS: Normal data were produced for each test across each decade cohort. Gradual decline in balance performance was confirmed, with significant effect for age demonstrated. CONCLUSION: New normative data across the adult age decades are available for these clinical tests. Use of clinical balance tests could complement other balance tests and be used to screen women aged 40 to 60 whose performance is outside the normal values for age and to decrease later falls risk.

Effect of line of sight propagation on capacity of an indoor MIMO system

In this paper the performance of a multiple input multiple output (MIMO) wireless communication system operating in an indoor environment, featuring both line of sight (LOS) and non-line of sight (NLOS) signal propagation, is assessed. In the model the scattering objects are assumed to be uniformly distributed in an area surrounding the transmitting and receiving array antennas. Mutual coupling effects in the arrays are treated in an exact manner. However interactions with scattering objects are taken into account via a single bounce approach. Computer simulations are carried out for the system capacity for varying inter-element spacing in the receiving array for assumed values of LOS/NLOS power fraction and signal to noise ratio (SNR).

Design, modelling and analysis of a six component force balance for hypervelocity wind tunnel testing

A combination of modelling and analysis techniques was used to design a six component force balance. The balance was designed specifically for the measurement of impulsive aerodynamic forces and moments characteristic of hypervelocity shock tunnel testing using the stress wave force measurement technique. Aerodynamic modelling was used to estimate the magnitude and distribution of forces and finite element modelling to determine the mechanical response of proposed balance designs. Simulation of balance performance was based on aerodynamic loads and mechanical responses using convolution techniques. Deconvolution was then used to assess balance performance and to guide further design modifications leading to the final balance design. (C) 2001 Elsevier Science Ltd. All rights reserved.

Is the method of signal analysis and test selection important for measuring standing balance in subjects with persistent whiplash?

Dizziness and or unsteadiness, associated with episodes of loss of balance, are frequent complaints in those suffering from persistent problems following a whiplash injury. Research has been inconclusive with respect to possible aetiology, discriminative tests and analyses used. The aim of this pilot research was to identify the test conditions and the most appropriate method for the analysis of sway that may differentiate subjects with persistent whiplash associated disorders (WAD) from healthy controls. The six conditions of the Clinical Test for Sensory Interaction in Balance was performed in both comfortable and tandem stance in 20 subjects with persistent WAD compared to 20 control subjects. The analyses were carried out using a traditional method of measurement, total sway distance, to results obtained from the use of wavelet analysis. Subjects with WAD were significantly less able to complete the tandem stance tests on a firm surface than controls. In comfortable stance, using wavelet analysis, significant differences between subjects with WAD and the control group were evident in total energy of the trace for all test conditions apart from eyes open on the firm surface. In contrast, the results of the analysis using total sway distance revealed no significant differences between groups across all six conditions. Wavelet analysis may be more appropriate for detecting disturbances in balance in whiplash subjects because the technique allows separation of the noise from the underlying systematic effect of sway. These findings will be used to direct future studies on the aeitiology of balance disturbances in WAD. (c) 2004 Elsevier B.V. All rights reserved.

What's scene and not seen: Influences of movement and task upon what we see

Studies concerning the processing of natural scenes using eye movement equipment have revealed that observers retain surprisingly little information from one fixation to the next. Other studies, in which fixation remained constant while elements within the scene were changed, have shown that, even without refixation, objects within a scene are surprisingly poorly represented. Although this effect has been studied in some detail in static scenes, there has been relatively little work on scenes as we would normally experience them, namely dynamic and ever changing. This paper describes a comparable form of change blindness in dynamic scenes, in which detection is performed in the presence of simulated observer motion. The study also describes how change blindness is affected by the manner in which the observer interacts with the environment, by comparing detection performance of an observer as the passenger or driver of a car. The experiments show that observer motion reduces the detection of orientation and location changes, and that the task of driving causes a concentration of object analysis on or near the line of motion, relative to passive viewing of the same scene.

Evolution of a mate recognition system after hybridization between two Drosophila species

I investigated the genetic relationship between male and female components of the mate recognition system and how this relationship influenced the subsequent evolution of the two traits, in a series of replicate populations of interspecific hybrids. Thirty populations of hybrids between Drosophila serrata and Drosophila birchii were established and maintained for 24 generations. At the fifth generation after hybridization, the mating success of hybrid individuals with the D. serrata parent was determined. The genetic correlation between male and female components of the male recognition system, as a consequence of pleiotropy or tight physical linkage, was found to be significant but low (r = 0.388). This result suggested that pleiotropy may play only a minor role in the evolution of mate recognition in this system. At the twenty-fourth generation after hybridization, the mating success of the hybrids was again determined. The evolution of male and female components was investigated by analyzing the direction of evolution of each hybrid line with respect to its initial position in relation to the genetic regression. Male and female components appeared to converge on a single equilibrium point, rather than evolving along trajectories with slope equal to the genetic regression, toward a line of equilibria.

Development of P2 olfactory glomeruli in P2-internal ribosome entry site-tau-lacZ transgenic mice

Primary olfactory neurons project their axons to the olfactory bulb, where they terminate in discrete loci called glomeruli. All neurons expressing the same odorant receptor appear to terminate in a few glomeruli in each olfactory bulb. In the P2-IRES-tau-LacZ line of transgenic mice, LacZ is expressed in the perikarya and axons of primary olfactory neurons that express the P2 odorant receptor. In the present study, we examined the developmental appearance of P2 neurons, the topographical targeting of P2 axons, as well as the formation of P2 glomeruli in the olfactory bulb. P2 axons were first detected in the olfactory nerve fiber layer at embryonic day 14.5 (E14.5), and by E15.5 these axons terminated in a broad locus in the presumptive glomerular layer. During the next 5 embryonic days, the elongated cluster of axons developed into discrete glomerulus-like structures. In many cases, glomeruli appeared as pairs, which were initially connected by a fascicle of P2 axons. This connection was lost by postnatal day 7.5, and double glomeruli at the same locus were observed in 85% of adult animals. During the early postnatal period, there was considerable mistargeting of P2 axons. In some cases P2 axons entered inappropriate glomeruli or continued to grow past the glomerular layer into the deeper layers of the olfactory bulb. These aberrant axons were not observed in adult animals. These results indicate that olfactory axons exhibit errors while converging onto a specific glomerulus and suggest that guidance cues may be diffusely distributed at target sites in the olfactory bulb.

E7 oncoprotein of human papillomavirus type 16 expressed constitutively in the epidermis has no effect on E7-specific B- or Th-repertoires or on the immune response induced or sustained after immunization with E7 protein

A line of FVB (H-2(q)) mice transgenic for the E6/E7 open reading frames of Human Papillomavirus type 16 driven from the alpha-A crystallin promoter expresses E7 mRNA in lens and skin epithelium. E7 protein is detectable in adult skin, coinciding with the development or inflammatory skin disease, which progresses to papillomata and squamous carcinomata in some mice. By examining the outcome of parenteral immunization with E7 protein, we sought to determine whether endogenous expression of E7 in skin had induced a preexisting immune outcome, i.e., specific immunity or tolerance, or whether the mice remain naive (''ignorant'') to E7. Our data show that the antibody response to defined E7 B-epitopes, the proliferative response to Th epitopes, and the delayed-type hypersensitivity (DTH) response to whole E7 did not differ between groups or young and old E6/E7 transgenic mice (likely having different degrees of lifetime exposure to E7 protein) or between E6/E7-transgenic and nontransgenic parental strain control mice. Although an E7-specific CTL response could not be induced in the H-2(q) background of these mice, incorporation of a D-b allele into the genome allowed comparison of D-b-restricted CTL responses in E6/E7 transgenic and nontransgenic mice. Experiments indicated that the E7-immunization-induced CTL response did not differ significantly between E6/E7 transgenic and nontransgenic mice. We interpret these results to indicate that in spite of expression of E7 protein in adult skin, E6/E7 transgenic mice remain immunologically naive (ignorant) of E7 epitopes presented by immunization. (C) 1997 Academic Press.

Presentation of the HPV16E7 protein by skin grafts is insufficient to allow graft rejection in an E7-primed animal

The E7 transforming protein of Human Papillomavirus type 16 (HPV16) is expressed in the skin of a line of RIB mice transgenic for the E6 and E7 open reading frames of HPV16 driven from the alpha A crystallin promoter (FVB alpha AcryHPV16E6E7). We have transferred skin from FVB alpha AcryHPV16E6E7 mice to naive or E7-primed syngeneic NE recipients to assess whether the E7 protein of HPV16 can function as a minor transplantation antigen (MTA) and promote skin graft rejection. FVB mice did not reject E7 expressing tail or flank skin grafts. E7 immunized FVB x C57BL/6J mice recipients of FVB alpha AcryHPV16E6E7 x C57BL/6J skin generated humoral and DTH responses to E7 in vivo and E7-specific CTL precursors in the spleen, but failed to reject 57 expressing tail skin grafts by 100 days posttransfer. Thus although HPV16 E7 + ve mesenchymal and endodermal tumors can be eliminated by an E7-specific immune response, the same protein is unable to act as a MTA and promote graft rejection when expressed in skin cells. Lack of rejection of grafts expressing MTAs such as E7 may be relevant to the immunology of epithelial tumors expressing tumor-specific antigens and to our understanding of the immunology of diseases of the skin. (C) 1997 Academic Press.

Mutation analysis of the CDKN2A promoter in Australian melanoma families

Approximately 50% of all melanoma families worldwide show linkage to 9p21-22, but only about half of these have been shown to contain germ line CDKN2A mutations. It has been hypothesized that a proportion of these families carry mutations in the noncoding regions of CDKN2A. Several Canadian families have been reported to carry a mutation in the 5' UTR, at position -34 relative to the start site, which gives rise to a novel AUG translation initiation codon that markedly decreases translation from the wild-type AUG (Liu et al., 1999). Haplotype sharing in these Canadian families suggested that this mutation is of British origin. We sequenced 1,327 base pairs (bp) of CDKN2A, making up 1,116 bp of the 5' UTR and promoter, all of exon 1, and 61 bp of intron 1, in at least one melanoma case from 110 Australian families with three or more affected members known not to carry mutations within the p16 coding region. In addition, 431 bp upstream of the start codon was sequenced in an additional 253 affected probands from two-case melanoma families for which the CDKN2A mutation status was unknown. Several known polymorphisms at positions -33, -191, -493, and -735 were detected, in addition to four novel variants at positions 120, -252, -347, and -981 relative to the start codon. One of the probands from a two-case family was found to have the previously reported Q50R mutation. No family member was found to carry the mutation at position -34 or any other disease-associated mutation. For further investigation of noncoding CDKN2A mutations that may affect transcription, allele-specific expression analysis was carried out in 31 of the families with at least three affected members who showed either complete or indeterminate 9p haplotype sharing without CDKN2A exonic mutations. Reverse transcription polymerase chain reaction and automated sequencing showed expression of both CDKN2A alleles in all family members tested. The lack of CDKN2A promoter mutations and the absence of transcriptional silencing in the germ line of this cohort of families suggest that mutations in the promoter and 5' UTR play a very limited role in melanoma predisposition. (C) 2001 Wiley-Liss, Inc.

Let your feet do the walking: constraints on the stability of bipedal coordination

In this paper we consider whether the behaviour of the neural circuitry that controls lower limb movements in humans is shaped primarily by the spatiotemporal characteristics of bipedal gait patterns, or by selective pressures that are sensitive to considerations of balance and energetics. During the course of normal locomotion, the full dynamics of the neural circuitry are masked by the inertial properties of the limbs. In the present study, participants executed bipedal movements in conditions in which their feet were either unloaded or subject to additional inertial loads. Two patterns of rhythmic coordination were examined. In the in-phase mode, participants were required to flex their ankles and extend their ankles in synchrony. In the out-of-phase mode, the participants flexed one ankle while extending the other and vice versa. The frequency of movement was increased systematically throughout each experimental trial. All participants were able to maintain both the in-phase and the out-of-phase mode of coordination, to the point at which they could no longer increase their frequency of movement. Transitions between the two modes were not observed, and the stability of the out-of-phase and in-phase modes of coordination was equivalent at all movement frequencies. These findings indicate that, in humans, the behaviour of the neural circuitry underlying coordinated movements of the lower limbs is not constrained strongly by the spatiotemporal symmetries of bipedal gait patterns.

Mutation rates in the dihydrofolate reductase gene of Plasmodium falciparum

A new method has been established to define the limits on a spontaneous mutation rate for a gene in Plasmodium falciparum. The method combines mathematical modelling and large-scale in vitro culturing and calculates the difference in mutant frequencies at 2 separate time-points. We measured the mutation rate at 2 positions in the dihydrofolate reductase (DHFR) gene of 3D7, a pyrimethamine-sensitive line of P. fulciparum. This line was re-cloned and an effectively large population was treated with a selective pyrimethamine concentration of 40 nM. We detected point mutations at codon-46 (TTA to TCA) and codon-108 (ACC to AAC), resulting in serine replacing leucine and asparagine replacing serine respectively in the corresponding gene product. The substitutions caused a decrease in pyrimethamine sensitivity. By mathematical modelling we determined that the mutation rate at a given position in DHFR was low and occurred at less than 2(.)5 x 10(-9) mutations/DHFR gene/replication. This result has important implications for Plasmodium genetic diversity and antimalarial drug therapy by demonstrating that even with lon mutation rates anti-malarial resistance will inevitably arise when mutant alleles are selected under drug pressure.

Exercise-induced alterations in neutrophil degranulation and respiratory burst activity: possible mechanisms of action

Neutrophils constitute 50-60% of all circulating leukocytes; they present the first line of microbicidal defense and are involved in inflammatory responses. To examine immunocompetence in athletes, numerous studies have investigated the effects of exercise on the number of circulating neutrophils and their response to stimulation by chemotactic stimuli and activating factors. Exercise causes a biphasic increase in the number of neutrophils in the blood, arising from increases in catecholamine and cortisol concentrations. Moderate intensity exercise may enhance neutrophil respiratory burst activity, possibly through increases in the concentrations of growth hormone and the inflammatory cytokine IL-6. In contrast, intense or long duration exercise may suppress neutrophil degranulation and the production of reactive oxidants via elevated circulating concentrations of epinephrine (adrenaline) and cortisol. There is evidence of neutrophil degranulation and activation of the respiratory burst following exercise-induced muscle damage. In principle, improved responsiveness of neutrophils to stimulation following exercise of moderate intensity could mean that individuals participating in moderate exercise may have improved resistance to infection. Conversely, competitive athletes undertaking regular intense exercise may be at greater risk of contracting illness. However there are limited data to support this concept. To elucidate the cellular mechanisms involved in the neutrophil responses to exercise, researchers have examined changes in the expression of cell membrane receptors, the production and release of reactive oxidants and more recently, calcium signaling. The investigation of possible modifications of other signal transduction events following exercise has not been possible because of current methodological limitations. At present, variation in exercise-induced alterations in neutrophil function appears to be due to differences in exercise protocols, training status, sampling points and laboratory assay techniques.

Laminar disorganisation of mitral cells in the olfactory bulb does not affect topographic targeting of primary olfactory axons

Primary olfactory neurons expressing the same odorant receptor protein typically project to topographically fixed olfactory bulb sites. While cell adhesion molecules and odorant receptors have been implicated in guidance of primary olfactory axons. the postsynaptic mitral cells may also have a role in final target selection. We have examined the effect of disorganisation of the mitral cell soma layer in mutant mice heterozygous for the beta-subunit of platelet activating factor acetylhydrolase (Lis1(-/+)) on the targeting of primary olfactory axons. Lis1(-/+) mice display abnormal lamination of neurons in the olfactory bulb. Lis1(-/+) mice were crossed with the P2-IRES-tau:LacZ line of transgenic mice that selectively expresses beta-galactosidase in primary olfactory neurons expressing the P2 odorant receptor. LacZ histochemistry revealed blue-stained P2 axons that targeted topographically fixed glomeruli in these mice in a manner similar to that observed in the parent P2-IRES-tau:LacZ line. Thus, despite the aberrant organisation of postsynaptic mitral cells in Lis1(-/+) mice, primary olfactory axons continued to converge and form glomeruli at correct sites in the olfactory bulb. Next we examined whether challenging primary olfactory axons in adult Lis(-/+) mice with regeneration would affect their ability to converge and form glomeruli. Following partial chemical ablation of the olfactory neuroepithelium with dichlobenil, primary olfactory neurons die and are replaced by newly differentiating neurons that project axons to the olfactory bulb where they converge and form glomeruli. Despite the aberrant mitral cell layer in Lis(-/+) mice. primary olfactory axons continued to converge and form glomeruli during regeneration. Together these results demonstrate that the convergence of primary olfactory axons during development and regeneration is not affected by gross perturbations to the lamination of the mitral cell layer. Thus, these results support evidence from other studies indicating that mitral cells do not play a major role in the convergence and targeting of primary olfactory axons in the olfactory bulb. (C) 2002 Elsevier Science B.V. All rights reserved.