Prospective survey of tick paralysis in dogs

Objective To obtain information on tick paralysis in dogs, including the nature of disease, host signalment, tick-host relationship, treatment, disease progression and recovery, and preventive measures. Design A prospective survey of 577 dogs affected by tick paralysis was conducted during 1998. Forty-two veterinary clinics along the eastern coast of Australia were instructed to complete survey forms for the first 15 dogs that presented with tick paralysis during September to November. Results Five percent of dogs died from tick paralysis. Younger dogs were more likely to survive. Long coat length was associated with a greater tick burden but not greater tick size, whereas coat thickness had no bearing on either. Dogs with mild disease recovered more quickly from tick paralysis. Respiratory and gait scores reflected disease severity and were good prognostic indicators. The size of the tick did not reflect the severity of the clinical condition it induced in the host. No method of tick removal or in situ treatment improved recovery time or reduced mortality. However, the time spent in hospital was significantly less for dogs from which the live tick was manually removed. Inspiratory strider. evident in some dogs with tick paralysis, was not related to tick attachment on the neck. The use of acepromazine maleate or dexamethasone did not reduce recovery time or mortality. Increasing the dose of tick antitoxin serum (TAS) above 0.1 mL/kg had no effect on mortality or recovery time. Dogs with severe disease that received an additional dose of TAS were significantly less likely to survive. Subcutaneous use of TAS at the site of tick attachment was of no benefit in reducing mortality or time to initial clinical improvement. A registered preventative product had not been used on the majority of dogs. Clipping the coat to search for ticks did not reduce mortality. Conclusions Therapy needs to address cardiopulmonary dysfunction that may be due directly to the effect of tick toxin and not just respiratory compromise caused by progressive respiratory muscle failure.

The attentional demands of preferred and non-preferred gait patterns

The purpose of this study was to determine the attentional demands of natural and imposed gait, as well as the attentional costs of transitions between the walking and running co-ordination patterns. Seven healthy young men and four healthy young women undertook an auditory probe reaction time task concurrently with self-selected gait (Experiment 1) and imposed walking and running (Experiment 2) at different speeds on a motor-driven treadmill. In Experiment 1, where participants were free to choose their own movement pattern to match the speed of travel of the treadmill, normal gait control was shown to have a significant attentional cost, and hence not be automatic in the classical sense. However, this attentional cost did not differ between the two gait modes or at the transition point. In Experiment 2, where participants were required to maintain specific gait modes regardless of the treadmill speed, the maintenance of walking at speeds normally associated with running was found to have an attentional cost whereas this was not the case for running at normal walking speeds. Collectively the findings support a model of gait control in which the normal switching between gait modes is determined with minimal attention demand and in which it is possible to sustain non-preferred gait modes although, in the case of walking, only at a significant attentional/cognitive cost. © 2002 Elsevier Science B.V. All rights reserved.

Protein fold recognition score functions: Unusual construction strategies

We describe two ways of optimizing score functions for protein sequence to structure threading. The first method adjusts parameters to improve sequence to structure alignment. The second adjusts parameters so as to improve a score function's ability to rank alignments calculated in the first score function. Unlike those functions known as knowledge-based force fields, the resulting parameter sets do not rely on Boltzmann statistics, have no claim to representing free energies and are purely constructions for recognizing protein folds. The methods give a small improvement, but suggest that functions can be profitably optimized for very specific aspects of protein fold recognition, Proteins 1999;36:454-461. (C) 1999 Wiley-Liss, Inc.

Are transitions in human gait determined by mechanical, kinetic or energetic factors?

It is currently unclear whether it is the need to maintain metabolic efficiency, the need to keep skeletal loading below critical force levels, or simple mechanical factors that drive the walk-to-run (W R) and run-to-walk (R-W) transitions in human gait. Eighteen adults (9 males and 9 females) locomoted on an instrumented treadmill using their preferred gait. Each completed 2 ascending (W-R) and 2 descending (R-W) series of trials under three levels of loading (0%, 15% and 30% body weight). For each trial, participants locomoted for 60 s at each of 9 different speeds -4 speeds both above and below their preferred transition speed (PTS) plus their PTS. Evidence was sought for critical levels of key kinetic (maximum vertical force, impulse, first peak force, time to first peak force and maximum loading rate), energetic (oxygen consumption, transport cost) and mechanical variables (limb lengths, strength) predictive of the gait transition. Analyses suggested the kinetic variables of time to first peak force and loading rate as the most likely determinants of the W-R and R-W transitions. (C) 2003 Elsevier Science B.V. All rights reserved.

Outcomes after trans-tibial amputation: The relationship between quiet stance ability, strength of the hip abductor muscles and gait

Background and Purpose Previous research regarding the symmetry of trans-tibial amputees has examined weight distribution and various gait parameters between prosthetic and sound limbs. However, to date, no known research has determined if asymmetry is present in the strength of the hip abductor muscles or if correlations exist between these categories of symmetry. The purpose of the present study was, therefore, to document asymmetry present in stance, strength and gait measures, and to determine the relationship between these variables. Method Twenty-three elderly, unilateral trans-tibial amputees stood on two adjacent forceplates whilst the weight distribution and standard deviation (SD) of the anterior-posterior and the medio-lateral centre of pressure excursion (COPE) under each limb was recorded during four 40 s trials: quiet stance (QS), with eyes open and eyes closed; and even stance (ES), with eyes open and eyes closed. Gait measures (velocity, cadence, step and stride lengths, stance:swing ratio and period of double support) over 10 m of fast, yet safe walking and measures of the strength of hip abductor muscles were also obtained by use of a stride analyser and a dynamometer, respectively. Results No significant differences were found between QS and ES measures. However, significantly more weight was taken on the sound limb than on the amputated limb. Notably, more anterior-posterior movement occurred under the sound limb than the amputated limb, with this becoming more apparent with the eyes closed. Movement in the medio-lateral direction was found to be the same between sides. No differences in muscle strength or gait measures between limbs were demonstrated. However. strong hip abductor muscles were correlated with increased weight-bearing on the amputated limb, improved gait parameters and reduced medio-lateral COPE under the amputated limb. Conclusions This research confirms the asymmetrical nature of amputee stance and demonstrates symmetry of strength and gait measures between limbs. The correlations between hip abductor muscle strength, weight distribution and gait measures illustrates the importance of pre- and postoperative training of these muscles. Copyright © 2002 Whurr Publishers Ltd.

Prediction of mortality in patients without angina: Use of an exercise score and exercise echocardiography

Background Exercise testing has limited efficacy for identifying coronary artery disease (CAD) in the absence of anginal. symptoms. Exercise echocardiography is more accurate than standard exercise testing, but its efficacy in this situation has not been defined. We sought to identify whether the Duke treadmill. score or exercise echocardiography (ExE) could be used to identify risk in patients without anginal symptoms. Methods We studied 1859 patients without typical or atypical angina, heart failure, or a history or ECG evidence of infarction or CAD, who were referred for ExE, of whom 1832 (age 51 15 years, 944 men) were followed for up to 10 years. The presence and extent of ischaemia and scar were interpreted by expert reviewers at the time of the original study. Results Exercise provoked significant (>0.1 mV) ST segment depression in 215 patients (12%), and wall motion abnormalities in 137 (8%). Seventy-eight patients (4%) died before revascularization, only 17 from known cardiac causes. The independent predictors of death were age (RR 1.1, p

The diagnostic reliability of Internet-based observational kinematic gait analysis

We investigated the accuracy and reliability of observational kinematic gait assessments performed via a low-bandwidth Internet link (118 kbit/s) and a higher-speed Internet link (128 kbit/s). Twenty-four subjects were randomized to either bandwidth group. Gait was assessed with the Gait Assessment Rating Scale (GARS) in the traditional manner, which is from video-recordings, and with repeated measurements via the online method. Online assessment was found to provide as accurate a measure of gait performance as the traditional assessment (limits of agreement

A clinical and echocardiographic score for assigning risk of major events after dobutamine echocardiograms

OBJECTIVES We sought to develop and validate a risk score combining both clinical and dobutamine echocardiographic (DbE) features in 4,890 patients who underwent DbE at three expert laboratories and were followed for death or myocardial infarction for up to five years. BACKGROUND In contrast to exercise scores, no score exists to combine clinical, stress, and echocardiographic findings with DbE. METHODS Dobutamine echocardiography was performed for evaluation of known or suspected coronary artery disease in 3,156 patients at two sites in the U.S. After exclusion of patients with incomplete follow-up, 1,456 DbEs were randomly selected to develop a multivariate model for prediction of events. After simplification of each model for clinical use, the models were internally validated in the remaining DbE patients in the same series and externally validated in 1,733 patients in an independent series. RESULTS The following score was derived from regression models in the modeling group (160 events): DbE risk = (age (.) 0.02) + (heart failure + rate-pressure product <15,000) (.) 0.4 + (ischemia + scar) (.) 0.6. The presence of each variable was scored as 1 and its absence scored as 0, except for age (continuous variable). Using cutoff values of 1.2 and 2.6, patients were classified into groups with five-year event-free survivals >95%, 75% to 95%, and <75%. Application of the score in the internal validation group (265 events) gave equivalent results, as did its application in the external validation group (494 events, C index = 0.72). CONCLUSIONS A risk score based on clinical and echocardiographic data may be used to quantify the risk of events in patients undergoing DbE. (C) 2004 by the American College of Cardiology Foundation.

A simple lifestyle score predicts survival in healthy elderly men

Background. Although improvements in life expectancy have been attributed in part to the adoption or a more prudent lifestyle, few studies have examined the association of lifestyle with survival, using several lifestyle factors simultaneously, in a healthy elderly population. Methods. We investigated the association of health related behaviors with mortality in 7989 men aged 65 to 83 years participating in a population-based trial in Perth, Western Australia, by calculating a lifestyle score as a simple tally of flow many or eight prudent behaviors each individual followed. Results. Invitations to screening produced a corrected response of 70.5%. Out of a possible score of 8.46% of men had a score of less than 5. Within 5 years, a total of 703 men (9%) had died from any cause. The hazard ratio in men with a low lifestyle score was 1.3 [95% confidence interval (CI): 1.1-1.5] compared with men with a score of 5 or more. Conclusions. Lifestyle remains an important predictor of mortality even in old age. Survival in older men without a history of cardiovascular disease can potentially be enhanced by promoting a healthy lifestyle. © 2004 Elsevier Inc, All rights reserved.

Does the type of concurrent task affect preferred and cued gait in people with Parkinson's disease?

Difficulty performing more than one task at a time is common in people with Parkinson's disease, resulting in interference with one or both tasks. While studies have shown that greater interference in gait occurs with more complex concurrent tasks, the impact of the type of concurrent task is unclear in the Parkinson's population. Thus the first purpose of this study was to investigate the effect of the concurrent task (calculation, language, or motor) on gait in people with Parkinson's disease. As visual cues are commonly used to aid stride regulation in people with Parkinson's disease, the second purpose of this study was to determine whether this method of increasing stride length was still effective if other tasks were performed simultaneously. Sixteen patients with Parkinson's disease and 16 gender- and age-matched controls performed six cognitive and motor concurrent tasks when seated, walking 10 m, and walking over visual cues. Stride length decreased in people with Parkinson's disease when performing the concurrent calculation and language tasks, but not with the motor task. The language task was more complex than the calculation task, thus the effect was not due to task complexity alone. Visual cues were effective in improving stride length whist maintaining velocity in people with Parkinson's disease, even when performed under dual task conditions. These findings highlight the importance of the task when assessing and retraining dual tasking during gait, and suggest that retraining dual tasking can occur whilst simultaneously using visual aids to regulate stride length.

Guidelines for filming digital camera video clips for the assessment of gait and movement disorders by teleneurology

Digital still cameras capable of filming short video clips are readily available, but the quality of these recordings for telemedicine has not been reported. We performed a blinded study using four commonly available digital cameras. A simulated patient with a hemiplegic gait pattern was filmed by the same videographer in an identical, brightly lit indoor setting. Six neurologists viewed the blinded video clips on their PC and comparisons were made between cameras, between video clips recorded with and without a tripod, and between video clips filmed on high- or low-quality settings. Use of a tripod had a smaller effect than expected, while images taken on a high-quality setting were strongly preferred to those taken on a low-quality setting. Although there was some variability in video quality between selected cameras, all were of sufficient quality to identify physical signs such as gait and tremor. Adequate-quality video clips of movement disorders can be produced with low-cost cameras and transmitted by email for teleneurology purposes.