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1.
Mar Pollut Bull ; 188: 114654, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36736258

ABSTRACT

The presence of in-feed anti-sea lice drugs and their relationship with organic enrichment is poorly understood in sediment surrounding salmon farms. Using data from an aquaculture monitoring program (2018-2020), we describe this relationship at ten sites in four Canadian provinces. Three anti-sea lice pesticides (lufenuron, teflubenzuron, emamectin benzoate and metabolite desmethyl emamectin benzoate), and one antibiotic (oxytetracycline) were detected. Concentrations were often below limits of quantification. Values are also lower than those reported in other aquaculture salmon-producing countries. Highest concentrations, along with organic enrichment, were observed ~200 m of cages with lower concentrations detected up to 1.5 km away. Most samples had at least two drugs present: 75.2 % (British Columbia), 91.4 % (Newfoundland), and 54.8 % (New Brunswick/Nova Scotia) highlighting the potential for cumulative effects. Emamectin benzoate and oxytetracycline were detected four and three years respectively after last known treatments, demonstrating the need for research on overall persistence of compounds.


Subject(s)
Copepoda , Fish Diseases , Oxytetracycline , Salmo salar , Animals , Anti-Bacterial Agents/pharmacology , Oxytetracycline/pharmacology , Aquaculture , Geologic Sediments , British Columbia
2.
Mar Pollut Bull ; 169: 112557, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34089964

ABSTRACT

Several trace-elements have been identified as indicators of finfish aquaculture organic enrichment. In this study, sediment sampling at finfish farms was completed as part of an Aquaculture Monitoring Program in three distinct Canadian regions. Despite diverse datasets, multivariate analyses show a consistent clustering of known direct (Cu and Zn) and indirect (Cd, Mo and U) tracers of aquaculture activities with sediment organic matter (OM) and/or total dissolved sulfides concentrations. OM content was also a predictor of Cu, Zn, Mo and U concentrations according to decision tree analyses. Distance from cages did not emerge as a strong driver of differences among sampling points; however, a tendency towards negative associations is clear especially for Zn. Enriched stations as determined after geochemical normalization were mostly localized within 150 m of net-pens. Selected trace-elements (in particular Zn) can be useful indicators of aquaculture organic enrichment in different ecosystems and valuable tools for monitoring programs.


Subject(s)
Metals, Heavy , Trace Elements , Water Pollutants, Chemical , Aquaculture , Canada , Ecosystem , Environmental Monitoring , Geologic Sediments , Metals, Heavy/analysis , Trace Elements/analysis , Water Pollutants, Chemical/analysis
3.
Ann R Coll Surg Engl ; 102(9): 689-692, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32538119

ABSTRACT

INTRODUCTION: Placement of a duodenal or pyloric stent is a recognised palliative procedure for symptomatic relief of malignant gastric outlet obstruction. This procedure can be associated with significant complications, reinterventions and poor long-term relief of obstructive symptoms. However, there may be a faster return to diet and shorter hospital stay in comparison to other palliative procedures (eg gastrojejunostomy). The aim of this study was to determine the safety and efficacy of duodenal stenting in our regional district general hospital in comparison to that of larger tertiary centres. MATERIALS AND METHODS: All patients with gastric outlet obstruction who had duodenal stent placement attempted in our region between 1 August 2013 and 31 July 2018 were identified by retrospective analysis of prospectively maintained coding databases and medical notes. Patient demographics, safety outcomes and efficacy outcomes were then extracted. Results were interpreted with respect to data from best available published evidence from larger tertiary centres. RESULTS: Of 43 duodenal stent insertion attempts, 84% had a successful return to diet, 18% underwent reintervention, 18% suffered adverse events, mean length of stay post-intervention was 8.6 days and mean survival post-intervention was 132 days. CONCLUSIONS: Patients with malignant gastric outlet obstruction in whom duodenal stent placement was attempted had similar outcomes to published data from larger tertiary centres. Duodenal stent placement remains an acceptable treatment option for these patients in our region.


Subject(s)
Duodenum/surgery , Gastric Outlet Obstruction/surgery , Stents , Adult , Aged , Aged, 80 and over , Female , Hospitals, District , Hospitals, General , Humans , Male , Middle Aged , Prosthesis Implantation/adverse effects , Prosthesis Implantation/methods , Retrospective Studies , Stents/adverse effects , Treatment Outcome
4.
Haemophilia ; 24(5): 733-740, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29963724

ABSTRACT

INTRODUCTION: Recombinant factor VIII (rFVIII) products with extended half-lives, such as BAY 94-9027, can potentially maintain higher FVIII levels for longer periods of time, thus providing improved bleeding protection vs standard-acting FVIII products. AIM: To characterize the pharmacokinetic (PK) profile of BAY 94-9027 from phase 1, phase 2/3 (PROTECT VIII) and phase 3 (PROTECT VIII Kids) clinical trials in adults, adolescents and children with severe haemophilia A METHODS: Patients with severe haemophilia A (FVIII <1%) with >50 FVIII exposure days (EDs) and no history of inhibitors were included in the phase 1 (18-65 years, ≥150 EDs), PROTECT VIII (12-65 years, ≥150 EDs) and PROTECT VIII Kids (<12 years, >50 EDs) trials. PK parameters were assessed following a 25-IU/kg or 60-IU/kg BAY 94-9027 dose in the phase 1 study after the first and repeated infusion, in PROTECT VIII after the first and repeated 60-IU/kg infusion and in PROTECT VIII Kids after a single 60-IU/kg infusion. The chromogenic assay was used to assess FVIII activity. RESULTS: Compared with sucrose-formulated rFVIII, BAY 94-9027 had reduced clearance that resulted in a ~1.4-fold increase in half-life and dose-normalized area under the curve (AUC). The BAY 94-9027 PK profile was comparable after single- and repeated-dose administrations. Dose-proportional increases were observed between 25- and 60-IU/kg administrations. BAY 94-9027 PK characteristics were age dependent, consistent with other FVIII products. CONCLUSIONS: BAY 94-9027 shows an extended half-life and increased AUC vs standard-acting FVIII products. These PK characteristics will result in higher FVIII levels for longer duration.


Subject(s)
Factor VIII/therapeutic use , Hemophilia A/drug therapy , Polyethylene Glycols/therapeutic use , Adolescent , Adult , Aged , Child , Child, Preschool , Factor VIII/pharmacokinetics , Factor VIII/pharmacology , Hemophilia A/pathology , Humans , Infant , Infant, Newborn , Middle Aged , Polyethylene Glycols/pharmacokinetics , Polyethylene Glycols/pharmacology , Young Adult
5.
Neuroscience ; 312: 48-57, 2016 Jan 15.
Article in English | MEDLINE | ID: mdl-26556065

ABSTRACT

After limb amputation, patients often wake up with a vivid perception of the presence of the missing limb, called "phantom limb". Phantom limbs have mostly been studied with respect to pain sensation. But patients can experience many other phantom sensations, including voluntary movements. The goal of the present study was to quantify phantom movement kinematics and relate these to intact limb kinematics and to the time elapsed since amputation. Six upper arm and two forearm amputees with various delays since amputation (6months to 32years) performed phantom finger, hand and wrist movements at self-chosen comfortable velocities. The kinematics of the phantom movements was indirectly obtained via the intact limb that synchronously mimicked the phantom limb movements, using a Cyberglove® for measuring finger movements and an inertial measurement unit for wrist movements. Results show that the execution of phantom movements is perceived as "natural" but effortful. The types of phantom movements that can be performed are variable between the patients but they could all perform thumb flexion/extension and global hand opening/closure. Finger extension movements appeared to be 24% faster than finger flexion movements. Neither the number of types of phantom movements that can be executed nor the kinematic characteristics were related to the elapsed time since amputation, highlighting the persistence of post-amputation neural adaptation. We hypothesize that the perceived slowness of phantom movements is related to altered proprioceptive feedback that cannot be recalibrated by lack of visual feedback during phantom movement execution.


Subject(s)
Feedback, Sensory/physiology , Fingers/physiopathology , Motor Activity/physiology , Neuronal Plasticity/physiology , Phantom Limb/physiopathology , Proprioception/physiology , Wrist/physiopathology , Adult , Aged , Amputees , Biomechanical Phenomena , Female , Humans , Male , Middle Aged , Time Factors
6.
J Nanosci Nanotechnol ; 15(9): 6651-62, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26716224

ABSTRACT

Titanium dioxide coatings were deposited on the surface of titanium foils by Thermal Plasma Spray (TPS) process. Three different TiO2 coatings were prepared using the commercial TiO2-P25 nanopowder and titanium isopropoxide precursor solution as feed-stocks. Structure and morphology of the TiO2-P25 powder and the plasma sprayed coatings were analyzed by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption-desorption isotherms, UV-visible spectroscopy and Scanning Electron Microscopy (SEM). XRD and Raman results indicate that the TiO2 coatings were composed of an anatase/rutile mixture that is conditioned by the suspension composition used to be sprayed. Coatings prepared from TiO2-P25 nanoparticles in water suspension (NW-P25) and titanium isopropoxide solution suspension (NSP-P25) are incorporated into the coatings without phase transformation and their anatase/rutile ratio percentage remains very similar to the starting TiO2-P25 powder. On the contrary, when titanium isopropoxide solution is used for spraying (SP), the amount of rutile increases in the final TiO2 coating. SEM analysis also reveals different microstructure morphology, coating thickness, density and porosity of the three TiO2 films that depend significantly on the type of feed-stock employed. Interestingly, we have observed the role of titanium isopropoxide in the formation of more porous and cohesive layers of TiO2. The NSP-P25 coating, prepared with a mix of titanium isopropoxide solution based on TiO2 nanoparticles, presents higher deposition efficiencies and higher coating thickness than the film prepared with nanoparticles suspended in water (NW-P25) or with titanium isopropoxide solutions (SP). This is due to the precursor solution is acting as the cement between TiO2 nanoparticles, improving the cohesive strength of the coating. In sum, NSP-P25 and NW-P25 coatings display a good photocatalytic potential, based on their light absorption properties and mechanical stability. Band gap of the nanoparticulated coatings displays a light absorption at wavelengths below 379 and 399 nm for NW-P25 and NSP-P25 respectively. On the contrary, the SP coating, despite to present lower band-gap value, has bad cohesive properties with surface crackings that makes it mechanically unstable. Therefore, mixtures of P25 nanoparticles with titanium isopropoxide as feed-stock materials can produce promising photocatalytic coatings.


Subject(s)
Nanoparticles/chemistry , Plasma Gases/chemistry , Titanium/chemistry , Materials Testing , Surface Properties
7.
J Thromb Haemost ; 12(4): 488-96, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24843882

ABSTRACT

BACKGROUND: BAY 94-9027 is a B-domain-deleted recombinant factor VIII (rFVIII) with site-specific attachment of poly(ethylene glycol) that has shown an extended half-life in animal models of hemophilia. OBJECTIVES: To assess the pharmacokinetics and safety of BAY 94-9027 after single and repeated administration in subjects with severe hemophilia A. PATIENTS/METHODS: This 8-week, prospective, multicenter, open-label, phase I trial was conducted in 14 subjects aged 21­58 years with FVIII of < 1%, ≥ 150 days of exposure to FVIII, and no history of FVIII inhibitors. After a ≥ 3-day washout, subjects received a single dose of sucrose-formulated rFVIII (rFVIII-FS) (cohort 1 [n = 7], 25 IU kg−1; cohort 2 [n = 7], 50 IU kg−1) for a 48-h pharmacokinetic (PK) study. After another ≥ 3-day washout, cohort 1 received twice-weekly BAY 94-9027 at 25 IU kg−1 (16 doses), and cohort 2 received once-weekly BAY 94-9027 at 60 IU kg−1 (nine doses). A 168-h PK study was performed after the first and last BAY 94-9027 doses. RESULTS: BAY 94-9027 showed equivalent recovery and an improved PK profile vs. rFVIII-FS, with a half-life of ~ 19 h (vs. ~ 13.0 h for rFVIII-FS). BAY 94-9027 was well tolerated, and no immunogenicity was observed. CONCLUSIONS: This phase I study demonstrates that BAY 94-9027 has an extended half-life in subjects with hemophilia A and, after multiple dosing, was well tolerated with no immunogenicity during the 8-week trial. A phase III study in a larger number of subjects is underway to fully characterize how this prolonged half-life will permit less frequent prophylaxis dosing for patients with hemophilia.


Subject(s)
Factor VIII/chemistry , Factor VIII/pharmacokinetics , Hemophilia A/drug therapy , Peptide Fragments/chemistry , Peptide Fragments/pharmacokinetics , Polyethylene Glycols/chemistry , Adult , Animals , Hemophilia A/blood , Humans , Male , Middle Aged , Polyethylene Glycols/pharmacokinetics , Prospective Studies , Recombinant Proteins/chemistry , Recombinant Proteins/pharmacokinetics , Treatment Outcome , Young Adult
8.
Sci Justice ; 52(4): 259-67, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23068777

ABSTRACT

The evidential significance of car seat fibres has been investigated. Thirty six samples of car seat fabric were examined and the fibres catalogued according to their morphology and characteristics. The majority of car seat fibres were black or grey thick polyester fibres that were either dyed or pigmented. The MSP spectra produced were unlike those usually obtained from black or grey polyester fibres used in clothing. Tapings taken from car seats were examined for car seat fibres, various types were found showing that these fibres are expected to shed from the fabric albeit in low numbers, unless the vehicle is older. No fibres that matched the samples of the car seat fabric were found on the tapings of the car seats. One hundred garments were examined for car seat fibres, 10% of garments had populations of such fibres present and 41% had at least one car seat fibre present. None of these fibres matched the samples of the car seat fabric or those from the car seat tapings.

9.
Forensic Sci Int ; 222(1-3): 200-7, 2012 Oct 10.
Article in English | MEDLINE | ID: mdl-22727570

ABSTRACT

A collaborative study on Raman spectroscopy and microspectrophotometry (MSP) was carried out by members of the ENFSI (European Network of Forensic Science Institutes) European Fibres Group (EFG) on different dyed cotton fabrics. The detection limits of the two methods were tested on two cotton sets with a dye concentration ranging from 0.5 to 0.005% (w/w). This survey shows that it is possible to detect the presence of dye in fibres with concentrations below that detectable by the traditional methods of light microscopy and microspectrophotometry (MSP). The MSP detection limit for the dyes used in this study was found to be a concentration of 0.5% (w/w). At this concentration, the fibres appear colourless with light microscopy. Raman spectroscopy clearly shows a higher potential to detect concentrations of dyes as low as 0.05% for the yellow dye RY145 and 0.005% for the blue dye RB221. This detection limit was found to depend both on the chemical composition of the dye itself and on the analytical conditions, particularly the laser wavelength. Furthermore, analysis of binary mixtures of dyes showed that while the minor dye was detected at 1.5% (w/w) (30% of the total dye concentration) using microspectrophotometry, it was detected at a level as low as 0.05% (w/w) (10% of the total dye concentration) using Raman spectroscopy. This work also highlights the importance of a flexible Raman instrument equipped with several lasers at different wavelengths for the analysis of dyed fibres. The operator and the set up of the analytical conditions are also of prime importance in order to obtain high quality spectra. Changing the laser wavelength is important to detect different dyes in a mixture.

10.
J Neurophysiol ; 107(9): 2541-8, 2012 May.
Article in English | MEDLINE | ID: mdl-22298835

ABSTRACT

Gravitational force level is well-known to influence arm motor control. Specifically, hyper- or microgravity environments drastically change pointing accuracy and kinematics, particularly during initial exposure. These modifications are thought to partly reflect impairment in arm position sense. Here we investigated whether applying normogravitational constraints at joint level during microgravity episodes of parabolic flights could restore movement accuracy equivalent to that observed on Earth. Subjects with eyes closed performed arm reaching movements toward predefined sagittal angular positions in four environment conditions: normogravity, hypergravity, microgravity, and microgravity with elastic bands attached to the arm to mimic gravity-like torque at the shoulder joint. We found that subjects overshot and undershot the target orientations in hypergravity and microgravity, respectively, relative to a normogravity baseline. Strikingly, adding gravity-like torque prior to and during movements performed in microgravity allowed subjects to be as accurate as in normogravity. In the former condition, arm movement kinematics, as notably illustrated by the relative time to peak velocity, were also unchanged relative to normogravity, whereas significant modifications were found in hyper- and microgravity. Overall, these results suggest that arm motor planning and control are tuned with respect to gravitational information issued from joint torque, which presumably enhances arm position sense and activates internal models optimally adapted to the gravitoinertial environment.


Subject(s)
Arm/physiology , Goals , Gravitation , Movement/physiology , Torque , Weightlessness , Adult , Female , Humans , Male , Psychomotor Performance/physiology
11.
Sci Justice ; 50(3): 127-37, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20709273

ABSTRACT

One hundred outer-garments were examined for microscopic fragments of polyurethane foam. Low power stereomicroscopy was used to classify fragments into 18 groups according to macroscopic colour. Amber, pale yellow and black were the most frequently encountered, whilst navy, pale blue, bright pink, beige, brown, pale green, peach and white were the least frequently encountered. High power comparison/fluorescence microscopy was used to discriminate 166 populations within 16 colour groupings. The majority (95.2%) of populations consisted of three fragments or less. This study demonstrates that the background population of foam fragments on an outer-garment consists of low numbers representing various colours. Therefore, finding a large population of microscopically indistinguishable fragments within a casework situation has the potential to be considered highly significant evidentially.

12.
Neuroimage ; 49(2): 1190-9, 2010 Jan 15.
Article in English | MEDLINE | ID: mdl-19796691

ABSTRACT

We explored relationships between decline in cognitive processing speed (CPS) and change in frontal lobe MRI/MRS-based indices of cerebral integrity in 38 healthy adults (age 57-90 years). CPS was assessed using a battery of four timed neuropsychological tests: Grooved Pegboard, Coding, Symbol Digit Modalities Test and Category Fluency (Fruits and Furniture). The neuropsychological tests were factor analyzed to extract two components of CPS: psychomotor (PM) and psychophysical (PP). MRI-based indices of cerebral integrity included three cortical measurements per hemisphere (GM thickness, intergyral and sulcal spans) and two subcortical indices (fractional anisotropy (FA), measured using track-based spatial statistics (TBSS), and the volume of hyperintense WM (HWM)). MRS indices included levels of choline-containing compounds (GPC+PC), phosphocreatine plus creatine (PCr+Cr), and N-acetylaspartate (NAA), measured bilaterally in the frontal WM bundles. A substantial fraction of the variance in the PM-CPS (58%) was attributed to atrophic changes in frontal WM, observed as increases in sulcal span, declines in FA values and reductions in concentrations of NAA and choline-containing compounds. A smaller proportion (20%) of variance in the PP-CPS could be explained by bilateral increases in frontal sulcal span and increases in HWM volumes.


Subject(s)
Cognition/physiology , Frontal Lobe/anatomy & histology , Frontal Lobe/physiology , Aged , Aged, 80 and over , Anisotropy , Aspartic Acid/analogs & derivatives , Aspartic Acid/metabolism , Choline/metabolism , Creatine/metabolism , Female , Humans , Magnetic Resonance Imaging , Magnetic Resonance Spectroscopy , Male , Middle Aged , Nerve Fibers, Myelinated/physiology , Neuropsychological Tests , Organ Size , Phosphocreatine/metabolism , Time Factors
13.
Neuroimage ; 45(1): 17-28, 2009 Mar 01.
Article in English | MEDLINE | ID: mdl-19095067

ABSTRACT

Relationships between structural MRI-based markers of declining cerebral integrity, and regional PET measurements of (18)FDG uptake have not been studied well in normal aging. In this manuscript we relate changes in cerebral morphology to regional cerebral glucose uptake for 14 major cortical areas in 19 healthy older individuals (age 59-92 years). Measurements of cerebral integrity included gray matter (GM) thickness, sulcal and intergyral spans, fractional anisotropy (FA) of water diffusion and volume of hyperintense WM (HWM) lesions. (18)FDG-PET measurements were converted to standard uptake values and corrected for partial volume artifact. Following this, cortical FDG uptake was significantly correlated with several indices of WM integrity that we previously observed to be sensitive to cognitive decline in executive function, including intergyral span and HWM volumes. Our findings suggest that the age-related decline in white matter integrity, observed as increases in HWM lesions, intergyral spans and reduction in FA, correlated with a decline in the global and regional cerebral glucose uptake. Our findings support the emerging consensus that WM integrity indices are sensitive predictors of declining cerebral health in normal aging. Specifically, age-related WM degradation in the thinly myelinated association tracts appears to track the decreases in global and regional rates of glucose uptake.


Subject(s)
Aging/metabolism , Aging/pathology , Brain/diagnostic imaging , Brain/metabolism , Fluorodeoxyglucose F18/pharmacokinetics , Nerve Fibers, Myelinated/diagnostic imaging , Nerve Fibers, Myelinated/metabolism , Neurons/diagnostic imaging , Neurons/metabolism , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Positron-Emission Tomography/methods , Radiopharmaceuticals/pharmacokinetics , Tissue Distribution
14.
Neuroimage ; 35(2): 478-87, 2007 Apr 01.
Article in English | MEDLINE | ID: mdl-17292629

ABSTRACT

White matter (WM) fractional anisotropy (FA) is thought to be related to WM integrity and decline in FA is often used as an index of decreasing WM health. However, the relationship of FA to other structural indices of cerebral health has not been well studied. We hypothesized that the decline in WM health will be associated with changes in several other indices of cerebral health. In this manuscript we studied the correlation between whole-brain/hemispheric/corpus callosum FA and gray matter (GM) thickness, sulcal span, and the volume of T2-hyperintense WM in a group of 31 healthy aging individuals (12 males/19 females) aged 57-82 years old. Individual subjects' FA measures were calculated from diffusion tracing imaging (DTI) data using tract-based spatial statistics--an approach specifically designed and validated for voxel-wise multi-subject FA analysis. Age-controlled correlation analysis showed that whole-brain average FA values were significantly and positively correlated with the subject's average GM thickness and negatively correlated with hyperintense WM volume. Intra-hemispheric correlations between FA and other measures of cerebral health had generally greater effect sizes than inter-hemispheric correction, with correlation between left FA and left GM thickness being the most significant (r=0.6, p<0.01). Regional analysis of FA values showed that late-myelinating fiber tracts of the genu of corpus callosum had higher association with other cerebral health indices. These data are consistent with the hypothesis that late-myelinating regions of the brain bear the brunt of age-related degenerative changes.


Subject(s)
Aging , Brain/anatomy & histology , Brain/physiology , Magnetic Resonance Imaging , Aged , Aged, 80 and over , Anisotropy , Female , Humans , Magnetic Resonance Imaging/statistics & numerical data , Male , Middle Aged
15.
Eur J Pediatr Surg ; 16(4): 269-71, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16981093

ABSTRACT

Handlebar type injuries are well documented in the paediatric population. We describe a case complicated by a biloma, which was successfully treated with percutaneous drainage, guided radiologically. The imaging findings including CT, MRI and nuclear medicine techniques are presented.


Subject(s)
Bicycling/injuries , Bile , Liver/injuries , Child , Humans , Magnetic Resonance Imaging , Male , Peritoneal Cavity
16.
Sci Justice ; 44(3): 179-86, 2004.
Article in English | MEDLINE | ID: mdl-15270458

ABSTRACT

Fibre mapping, more commonly known as one-to-one taping, was developed in Germany approximately twenty years ago. The technique facilitates the distribution of fibres on a surface to be recorded. The impact of this technique on the investigation of serious crime has been reported in the European Fibre Group on several occasions. This paper represents a case study of the application of the technique. It is believed to be the first time that this technique has been successfully applied in the United Kingdom.

17.
Exp Brain Res ; 156(4): 471-7, 2004 Jun.
Article in English | MEDLINE | ID: mdl-14968277

ABSTRACT

During lateral leg raising, a synergistic inclination of the supporting leg and trunk in the opposite direction to the leg movement is performed in order to preserve equilibrium. As first hypothesized by Pagano and Turvey (J Exp Psychol Hum Percept Perform, 1995, 21:1070-1087), the perception of limb orientation could be based on the orientation of the limb's inertia tensor. The purpose of this study was thus to explore whether the final upper body orientation (trunk inclination relative to vertical) depends on changes in the trunk inertia tensor. We imposed a loading condition, with total mass of 4 kg added to the subject's trunk in either a symmetrical or asymmetrical configuration. This changed the orientation of the trunk inertia tensor while keeping the total trunk mass constant. In order to separate any effects of the inertia tensor from the effects of gravitational torque, the experiment was carried out in normo- and microgravity. The results indicated that in normogravity the same final upper body orientation was maintained irrespective of the loading condition. In microgravity, regardless of loading conditions the same (but different from the normogravity) orientation of the upper body was achieved through different joint organizations: two joints (the hip and ankle joints of the supporting leg) in the asymmetrical loading condition, and one (hip) in the symmetrical loading condition. In order to determine whether the different orientations of the inertia tensor were perceived during the movement, the interjoint coordination was quantified by performing a principal components analysis (PCA) on the supporting and moving hips and on the supporting ankle joints. It was expected that different loading conditions would modify the principal component of the PCA. In normogravity, asymmetrical loading decreased the coupling between joints, while in microgravity a strong coupling was preserved whatever the loading condition. It was concluded that the trunk inertia tensor did not play a role during the lateral leg raising task because in spite of the absence of gravitational torque the final upper body orientation and the interjoint coupling were not influenced.


Subject(s)
Gravity Sensing/physiology , Orientation/physiology , Posture/physiology , Proprioception/physiology , Weightlessness Simulation , Adult , Biomechanical Phenomena , Extremities/innervation , Extremities/physiology , Humans , Joints/innervation , Joints/physiology , Male , Models, Neurological , Movement/physiology , Torque , Weight-Bearing/physiology
18.
Neurosci Lett ; 329(3): 314-8, 2002 Sep 06.
Article in English | MEDLINE | ID: mdl-12183039

ABSTRACT

We investigated the behavioral dynamics of human breathing-wrist movement coordination in a 1:1 frequency locking task. A pronation-supination wrist movement and a short trial duration were chosen to limit both mechanical and metabolic constraints on the respiratory system. Subjects voluntarily controlled their breathing rhythm to follow the metronome. We found that pronation-expiration and pronation-inspiration patterns coexisted as the (sole) stable fixed-point attractors of the coordination system. The pronation-expiration pattern was more stable than the pronation-inspiration pattern. Depending on the oscillation frequency, this differential stability gave rise to both absolute and relative coordination. These results show that simple behavioral laws of coordination encapsulate neural coupling dynamics evidenced from experimental research in human beings and animals. They challenge the classical view that such a coupling is not present for all imposed movement frequencies. Rather, relative coordination emerges as a result of the modification of coupling strength with frequency. These results can be accommodated by the asymmetric version of the HKB model of coordination dynamics. Thus, our data suggest that the principles and models of coordination dynamics may be taken as a reference to study the coupling of the motor and physiological subsystems involved in breathing-movement coordination.


Subject(s)
Arm/physiology , Movement/physiology , Respiratory Mechanics/physiology , Humans , Models, Neurological , Nonlinear Dynamics , Periodicity
19.
Immunogenetics ; 53(5): 382-94, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11486275

ABSTRACT

Human CD150 (SLAM) is a glycoprotein expressed on the surface of T, B, natural killer, and dendritic cells. The extracellular domain of CD150 is the receptor for measles virus and CD150 acts as a co-activator on T and B cells. We characterized the mouse and human CD150 genes, each of which comprises seven exons spanning approximately 32 kb. Mouse CD150 mRNA was detected in T cells and in most thymocyte subsets, except CD4-8- cells. Surprisingly, the CD4-8- thymocytes of CD3gammadeltanull mice, but not of Ragnull or severe combined immunodeficiency mice, expressed CD150. Whereas high levels of CD150 were found in Th1 cells, only small amounts were detectable in Th2 cells. CD150 expression was up-regulated upon in vitro activation of mouse T cells by anti-CD3. The complete mouse CD150 gene is highly homologous to its human orthologue in terms of nucleotide sequences and intron/exon organization. The human genomic sequences indicate that all isoforms detected so far have arisen from alternative splicing events. As judged by fluorescence in situ hybridization, mouse CD150 mapped to Chromosome (Chr) 1, band 1H2.2-2.3, and human CD150 was found on Chr 1q22. Human and mouse CD150 share sequence homologies with six other genes, five of which - CD84, CD229 (Ly-9), CD244 (2B4), CD48, and 19A - are localized in a 250-kb segment in close proximity to the human gene. Their location and their sequence similarities strongly suggest that the CD150 family of cell surface receptors arose via successive duplications of a common ancestral gene.


Subject(s)
Antigens, CD/genetics , Glycoproteins/genetics , Hematopoietic Stem Cells/immunology , Immunoglobulins/genetics , Intracellular Signaling Peptides and Proteins , Multigene Family , Receptors, Immunologic , Amino Acid Sequence , Animals , Base Sequence , Carrier Proteins/genetics , Chromosome Mapping , Cloning, Molecular , Gene Expression Regulation , Humans , In Situ Hybridization, Fluorescence , Lymphocyte Activation , Membrane Glycoproteins/genetics , Mice , Molecular Sequence Data , RNA Splicing , RNA, Messenger , Receptors, Cell Surface , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Signaling Lymphocytic Activation Molecule Associated Protein , Signaling Lymphocytic Activation Molecule Family , Signaling Lymphocytic Activation Molecule Family Member 1
20.
J Exp Child Psychol ; 78(4): 330-58, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11243693

ABSTRACT

Variability in strategy use has been measured and conceptualized in several ways. The present study sought to determine whether a sample of variability measures could be reduced to a smaller number of factors that the individual measures had in common. Factor analysis of five commonly used variability measures was performed separately on data from eight independent samples of children and adults. The results revealed that the variability measures could be reduced to one of two general types of variability: strategy diversity, which refers to the sheer number of strategies used, and strategy change, which refers to the number of trial-by-trial changes in strategy use. Support for this two-factor model of variability was found for all samples of children and adults. Moreover, each type of variability had distinctive relations with cognitive performance that varied with age. In general, strategy diversity was positively related to recall for children but not adults, whereas strategy change was negatively related to recall for adults but not children. Based on this evidence, three recommendations for researchers studying strategy variability are described.


Subject(s)
Memory , Adult , Child , Factor Analysis, Statistical , Humans , Mental Recall , Vocabulary
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