Reaching and stepping respond differently to medication and cueing in Parkinson's disease.

The basal ganglia contribute to internal timekeeping, and dopaminergic medication has been observed to moderate timing deficits associated with Parkinson's Disease (PD) during single joint movements. However, it is unclear whether similar effects can be observed in multi-joint movements. Twenty-five people with PD and twelve healthy peers performed repetitive reaching and stepping-in-place tasks with and without auditory cues at their self-selected maximal cadence.

A nationwide serological survey for Dirofilaria immitis in companion cats in the United States of America: 3.5% antibody and 0.3% antigen positivity.

Background: Feline heartworm disease (HWD) is a complex and often misdiagnosed disease in cats, caused by the filarial nematode Dirofilaria immitis. Despite its significant impact, studies reporting the prevalence of D. immitis in apparently healthy pet cats in the USA are lacking.

Sensitivity of discrete symmetry metrics: Implications for metric choice.

Gait asymmetry is present in several pathological populations, including those with Parkinson's disease, Huntington's disease, and stroke survivors. Previous studies suggest that commonly used discrete symmetry metrics, which compare single bilateral variables, may not be equally sensitive to underlying effects of asymmetry, and the use of a metric with low sensitivity could result in unnecessarily low statistical power. The purpose of this study was to provide a comprehensive assessment of the sensitivity of commonly used discrete symmetry metrics to better inform design of future studies.

Walking on Mild Slopes and Altering Arm Swing Each Induce Specific Strategies in Healthy Young Adults.

Slopes are present in everyday environments and require specific postural strategies for successful navigation; different arm strategies may be used to manage external perturbations while walking. It has yet to be determined what impact arm swing has on postural strategies and gait stability during sloped walking. We investigated the potentially interacting effects of surface slope and arm motion on gait stability and postural strategies in healthy young adults.

Effects of arm swing amplitude and lower limb asymmetry on motor variability patterns during treadmill gait.

Motor variability is a fundamental feature of gait. Altered arm swing and lower limb asymmetry (LLA) may be contributing factors having been shown to affect the magnitude and dynamics of variability in spatiotemporal and trunk motion. However, the effects on lower limb joints remain unclear.

Recovery of dynamic stability during slips unaffected by arm swing in people with Parkinson's Disease.

The arm elevation strategy assists in recovering stability during slips in healthy young and elderly individuals. However, in people with Parkinson's Disease, one of the main motor symptoms affecting the upper limbs is reduced arm swing which intensifies throughout the course of the disease before becoming absent. This holds direct implications for these individuals when encountering slips as the arm elevation strategy is an integral component in the interlimb slip response to restore stability.

The effect of various arm and walking conditions on postural dynamic stability when recovering from a trip perturbation.

Background: Appropriately responding to unexpected perturbations, such as a trip, is critical to sustain balance and avoid falling during walking.

Research Question: How do arm motion and walking asymmetry affect postural stability when recovering from a trip perturbation?

Methods: Fifteen healthy young individuals, who had no experience with treadmill induced perturbations, participated in this study. The Computer-Assisted Rehabilitation Environment system (CAREN-Extended) was used to simulate unexpected perturbations while walking symmetrically and asymmetrically with various arm swings (normal, bound, released).

The effects of arm swing amplitude and lower-limb asymmetry on gait stability.

Changes to arm swing and gait symmetry are symptomatic of several pathological gaits associated with reduced stability. The purpose of this study was to examine the relative contributions of arm swing and gait symmetry towards gait stability. We theorized that actively increasing arm swing would increase gait stability, while asymmetric walking would decrease gait stability.

Active arm swing and asymmetric walking leads to increased variability in trunk kinematics in young adults.

Fall induced injuries are a leading cause for occupational injuries with the majority originating from challenging same-level walking surfaces. Despite current perturbation and fall prevention paradigms, occupational fall prevalence remains stable. Typically, these paradigms do not account for arm swing which has been demonstrated to affect the center of mass' movement during walking.

Effect of arm motion on postural stability when recovering from a slip perturbation.

The aim of this study was to examine the effects of various arm swing on postural stability and recovery responses to an unexpected slip during treadmill walking. Fifteen healthy young adults (23.4 ± 2.

Medication and trial duration influence postural and pointing parameters during a standing repetitive pointing task in individuals with Parkinson's disease.

We aimed to determine the effects of levodopa medication on the performance of a repetitive pointing task while standing, and to investigate the optimal trial duration in individuals with Parkinson's disease, and older adults. Seventeen individuals with Parkinson's disease (5 freezers) and 9 older adults stood on force platforms for 30 s and 120 s while performing a bilateral repetitive pointing task, tracked by motion capture. Participants with Parkinson's disease were assessed on and off medication and older adults were also assessed on separate days.

Bringing inorganic chemistry to life with inspiration from R. J. P. Williams.

Our appreciation of the scholarly ideas and thinking of Bob Williams is illustrated here by a few of the areas in which he inspired us. His journey to bring inorganic chemistry to life began with an early interest in analytical chemistry, rationalising the relative stabilities of metal coordination complexes (The Irving-Williams Series), and elucidating the organometallic redox chemistry of vitamin B12. He (and Vallee) recognised that metal ions are in energised (entatic) states in proteins and enzymes, which themselves are dynamic structures of rods and springs.

Bert Lester Vallee: a lasting legacy.

The enlightened formation, by Bert and Kuggie Vallee, of a procedure whereby senior scientists spend short time of about a month at Harvard, Oxford and other institutions, is illustrated by the views and opinions of those selected.

Sensing nitrite through a pseudoazurin-nitrite reductase electron transfer relay.

Nitrite is converted to nitric oxide by haem or copper-containing enzymes in denitrifying bacteria during the process of denitrification. In designing an efficient biosensor, this enzymic turnover must be quantitatively assessed. The enzyme nitrite reductase from Alcaligenes faecalis contains a redox-active blue copper centre and a nonblue enzyme-active copper centre.

Redox properties of cytochrome p450BM3 measured by direct methods.

Cytochrome p450BM3 is a self-sufficient fatty acid monooxygenase consisting of a diflavin (FAD/FMN) reductase domain and a heme domain fused together in a single polypeptide chain. The multidomain structure makes it an ideal model system for studying the mechanism of electron transfer and for understanding p450 systems in general. Here we report the redox properties of the cytochrome p450BM3 wild-type holoenzyme, and its isolated FAD reductase and p450 heme domains, when immobilized in a didodecyldimethylammonium bromide film cast on an edge-plane graphite electrode.

Genetic modulation of metalloprotein electron transfer at bare gold.

Engineered metalloproteins and enzymes can be self assembled on pristine gold electrodes in robust, electrochemically-addressable, arrays.

Cofactor-independent oxygenation reactions catalyzed by soluble methane monooxygenase at the surface of a modified gold electrode.

Soluble methane monooxygenase (sMMO) is a three-component enzyme that catalyses dioxygen- and NAD(P)H-dependent oxygenation of methane and numerous other substrates. Oxygenation occurs at the binuclear iron active centre in the hydroxylase component (MMOH), to which electrons are passed from NAD(P)H via the reductase component (MMOR), along a pathway that is facilitated and controlled by the third component, protein B (MMOB). We previously demonstrated that electrons could be passed to MMOH from a hexapeptide-modified gold electrode and thus cyclic voltammetry could be used to measure the redox potentials of the MMOH active site.

The scanning probe microscopy of metalloproteins and metalloenzymes.

In recent years, the concept of microscopy and the ability to study processes at a truly molecular level have been revolutionised by the development of a family of instruments based on acquiring data through the scanning of a proximal probe across a surface. Scanning Probe Microscopes (SPMs) enable surface-confined structures to be resolved at ångstrom-resolution, in real time, and under a variety of controllable conditions. Despite initial difficulties, much progress has been in the application of this technology to the high-resolution analysis of biological systems; these have varied from complex cellular systems to molecular biopolymers.

A scanning tunneling microscopy (STM) investigation of complex formation between cytochrome P450(cam) and putidaredoxin.

We have previously reported the scanning tunnelling microscopy (STM) imaging under buffer of the heme monooxygenase cytochrome P450(cam) from Pseudomonas putida [Faraday Discuss. 116 (2000) 1]. We describe here the adsorption and STM imaging under buffer of complexes of a mutant of cytochrome P450(cam), K344C, and wild-type putidaredoxin (Pdx) on gold(111).

The ATP/metallothionein interaction: NMR and STM.

We have previously established that ATP binds to mammalian metallothionein-2 (MT). The interaction between ATP and MT and the associated conformational change of the protein affect the sulfhydryl reactivity and zinc transfer potential of MT [Jiang, L.-J.