Test-retest assessment of non-contrast MRI sequences to characterise and quantify the small bowel wall in healthy participants

Objective

Quantitative Magnetic Resonance Imaging sequences have been investigated as objective imaging biomarkers of fibrosis and inflammation in Crohn’s disease.

Aim

To determine the repeatability and inter- and intra-observer agreement of these measures in the prepared small bowel wall.

Methods

Ten healthy participants were scanned at 3 T on 2 separate occasions using T1 and T2 relaxometry, IVIM-DWI and MT sequences. Test–retest repeatability was assessed using the coefficient of variation (CoV) and intra-class correlation coefficients (ICCs) were used to evaluate the intra- and inter-observer agreement

Results

Test–retest repeatability in the bowel wall was excellent for apparent diffusion coefficient (ADC), magnetisation transfer ratio (MTR), T1, and diffusion coefficient D (CoV 5%, 7%, 8%, and 10%, respectively), good for perfusion fraction (PF) (CoV 20%) and acceptable for T2 (CoV 21%). Inter-observer agreement was good for the T2, D and ADC (ICC = 0.89, 0.86, 0.76, respectively) and moderate for T1 (ICC = 0.55). Intra-observer agreement was similar to inter-observer agreement.

Discussion

This study showed variable results between the different parameters measured. Test–retest repeatability was at least acceptable for all parameters except pseudo-diffusion coefficient D*. Good inter- and intra-observer agreement was obtained for T2, ADC and D, with these parameters performing best in this technical validation study.

Development and validation of a probe hybridization reverse-transcription quantitative PCR for detection of mamastrovirus 2 in domestic cats

Astroviruses are viral pathogens that have been associated with enteric and neurologic disease in a variety of species. The domestic cat is a prominent host, with reports of astroviral infection being both highly prevalent and widely distributed in the feline population. Despite the potential for inducing significant disease, especially within shelter environments, there is currently only one reliable method of detection: standard reverse-transcription PCR using pan-astrovirus degenerate primers (consensus RT-PCR) with product sequencing. Unfortunately, this process is relatively slow and costly. Quantitative real-time PCR (qPCR) represents an efficient, economical alternative, with the added benefit of viral load quantification. We developed a RT-qPCR assay using probe hybridization technique to detect conserved regions of mamastrovirus 2 extracted from fecal samples of domestic cats. Known positive and negative samples were tested, and results were compared with gold standard consensus RT-PCR and sequencing. A standard curve was employed to determine limits of detection. In order to assess analytic specificity, we tested several additional samples that had been collected from non-felid species and were known to contain non-target astroviruses. Discrepant results between consensus RT-PCR and RT-qPCR testing were further analyzed with a validation RT-PCR assay, using mamastrovirus 2-specific primers. Our probe hybridization RT-qPCR assay is reliable and effective for the detection of mamastrovirus 2. This assay will allow rapid, affordable detection and facilitate further research on astroviral infection within domestic cats.

Determination of the diversity of astroviruses in feces from cats in Florida

Astroviruses are small, nonenveloped RNA viruses that have been linked to numerous diseases in a variety of species, including enteric disease in humans and cheetahs. Species Mamastrovirus 2, previously known as feline astrovirus, has been isolated from the feces of domestic cats and cheetahs. A total of 122 cat fecal samples from Alachua County, FL Animal Services and the Veterinary Community Outreach Program at the University of Florida were analyzed, and 35 contained astroviral RNA that was amplified and identified using consensus RT-PCR and sequence analysis. Using phylogenetic analysis, 19 of the astroviral sequences were identified as Mamastrovirus 2, making it the most prevalent astrovirus in this population. Three samples were identified as an astrovirus similar to viruses previously identified in foxes in The Netherlands and a cat in California, and one was similar to a bat astrovirus. One astroviral sequence was identified as an Avastrovirus. Although a causative relationship between mamastroviruses and enteric disease in cats has yet to be established, it is clear that mamastroviruses are prevalent, and an understanding of prevalence of astroviral types may help direct future test development.

Evaluation of Blue Crab, Callinectes sapidus, Megalopal Settlement and Condition during the Deepwater Horizon Oil Spill

The Blue Crab, Callinectes sapidus, is a commercially, culturally, and ecologically significant species in the Gulf of Mexico (GOM), whose offshore stages were likely impacted by the Deepwater Horizon oil spill (DWH). To test for DWH effects and to better understand the planktonic ecology of this species, we monitored Callinectes spp. megalopal settlement and condition at sites within and outside of the spill extent during and one year after the DWH. We tested for DWH effects by comparing 2010 settlement against baseline data available for two sites, and by testing for differences in settlement and condition inside and outside of the spill extent. We also developed time series models to better understand natural drivers of daily settlement variation (seasonal and lunar trends, hydrodynamics, wind) during 2010 and 2011. Overall, we found that neither megalopal settlement nor body weight were significantly reduced at oiled sites, but that high unexplained variation and low statistical power made detection of even large effects unlikely. Time series models revealed remarkably consistent and relatively strong seasonal and lunar trends within sites (explaining on average 28% and 9% of variation, respectively), while wind and hydrodynamic effects were weak (1–5% variation explained) and variable among sites. This study provides insights into DWH impacts as well as the natural drivers of Callinectes spp. megalopal settlement across the northern GOM.

Sensory quality of meat from lambs fed garlic

The objective of this study was to determine whether the inclusion of garlic in a ration would have a negative impact on the flavour of lamb. The study used meat from 31 Merino wether lambs fed diets with varying levels of garlic (0%, 1.8% and 3.6%) for 10 weeks. Cooked samples of meat from the lambs were assessed for flavour and acceptability as lamb by an untrained consumer panel. There was no difference (P>0.05) between the treatments in flavour score, but the 3.6% garlic treatment group scored significantly higher in terms of acceptability as lamb (P<0.05) and was commented on positively by the panellists more frequently than the meat from any other treatment (P<0.05). These results suggest that the inclusion of garlic into the animals' feed did not have a negative impact on the flavour of the lamb and, at the high rate (3.6%), made the meat more acceptable to the panellists.

Methanol promotes atmospheric methane oxidation by methanotrophic cultures and soils

Two methanotrophic bacteria, Methylobacter albus BG8 and Methylosinus trichosporium OB3b, oxidized atmospheric methane during batch growth on methanol. Methane consumption was rapidly and substantially diminished (95% over 9 days) when washed cell suspensions were incubated without methanol in the presence of atmospheric methane (1.7 ppm). Methanotrophic activity was stimulated after methanol (10 mM) but not methane (1,000 ppm) addition. M. albus BG8 grown in continuous culture for 80 days with methanol retained the ability to oxidize atmospheric methane and oxidized methane in a chemostat air supply. Methane oxidation during growth on methanol was not affected by methane deprivation. Differences in the kinetics of methane uptake (apparent K(m) and V(max)) were observed between batch- and chemostat-grown cultures. The V(max) and apparent K(m) values (means +/- standard errors) for methanol-limited chemostat cultures were 133 +/- 46 nmol of methane 10 cells h and 916 +/- 235 ppm of methane (1.2 muM), respectively. These values were significantly lower than those determined with batch-grown cultures (V(max) of 648 +/- 195 nmol of methane 10 cells h and apparent K(m) of 5,025 +/- 1,234 ppm of methane [6.3 muM]). Methane consumption by soils was stimulated by the addition of methanol. These results suggest that methanol or other nonmethane substrates may promote atmospheric methane oxidation in situ.

Smoke-derived taint in wine: effect of postharvest smoke exposure of grapes on the chemical composition and sensory characteristics of wine

Although smoke exposure has been associated with the development of smoke taint in grapes and subsequently in wine, to date there have been no studies that have demonstrated a direct link. In this study, postharvest smoke exposure of grapes was utilized to demonstrate that smoke significantly influences the chemical composition and sensory characteristics of wine and causes an apparent 'smoke taint'. Verdelho grapes were exposed to straw-derived smoke for 1 h and then fermented according to two different winemaking treatments. Control wines were made by fermenting unsmoked grapes. Sensory studies established a perceivable difference between smoked and unsmoked wines; smoked wines were described as exhibiting 'smoky', 'dirty', 'earthy', 'burnt' and 'smoked meat' characteristics. Quantitative analysis, by means of gas chromatography-mass spectrometry, identified guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, eugenol, and furfural in each of the wines made from smoked grapes. However, these compounds were not detected in the unsmoked wines, and their origin is therefore attributed to the application of smoke. Increased ethanol concentrations and browning were also observed in wines made from grapes exposed to smoke.

Gait and postural stability in obese and nonobese prepubertal boys

OBJECTIVE

To examine differences in gait and postural stability of obese and nonobese prepubertal boys.

DESIGN

Percentage of gait cycle in double support was examined to determine significant differences. Postural stability was compared using temporal and frequency measures of the center of pressure in static stance.

SETTING

Gait was examined using videography on a 30-meter walkway. Postural stability was examined using a measurement platform.

PARTICIPANTS

Ten obese (>95th percentile in body mass index) and 10 nonobese (15th to 90th percentile in body mass index) prepubertal boys aged 8 to 10yrs.

INTERVENTION

Participants were examined at three walking cadences as determined by preferred gait cadence. Full vision, darkness, and visually confused conditions were used to accentuate static postural stability differences.

MAIN OUTCOME MEASURES

In the presence of dynamic stability differences (gait), static stability measures further investigated stability differences.

RESULTS

Obese boys spent significantly (p < .02) greater percentage of gait cycle in dual stance. Obese boys showed significantly (p < .01) greater sway areas, energy, and variability primarily in the medial/lateral direction.

CONCLUSIONS

Dual stance differences suggest diminished dynamic stability in obese boys. Greater sway areas in medial/lateral direction in obese boys and the absence of significant frequency measures suggest that the instability observed in obese boys is caused by excess weight rather than underlying postural instability.

Development of bilateral motor control in children with developmental coordination disorders

This research examined behavioral (i.e. movement time) and neuromuscular (EMG) characteristics of unilateral and bilateral aiming movements of children with normal motor development and children with developmental coordination disorders (DCD). Two age groups of children were studied: 6 to 7, and 9 to 10 year olds. Bilateral aiming movements involved moving the two hands to targets of either (1) the same amplitude--symmetrical bilateral movements, or (2) different amplitudes--asymmetrical bilateral movements. Unilateral aiming movements involved moving one hand to either near or far targets associated with that hand. In general, unilateral and bilateral movement times were slower in younger than older children, and in children with DCD than children with normal motor development. Our neuromuscular data suggest that the faster movement times that typically accompany increasing age in children may be the result of a change in the capacity to initiate antagonist muscle contractions. The prolonged burst of agonist activity and delayed onset of antagonist activity observed in children with DCD may contribute to their inability to produce fast, accurate unilateral movements. On both symmetrical and asymmetrical bilateral aiming movements, children with DCD had more performance errors and greater temporal inconsistencies between neuromuscular (EMG) parameters and behavioral (movement time) parameters than children with normal motor development. These new neuromuscular data suggest that there are important differences in the way the motor control systems of children with and without DCD organize bilateral aiming responses.

Alteration in plasmid DNA following natural transformation to populations of marine bacteria

This article examines alterations in a broad-host-range plasmid (pQSR50) that were observed following transfer to indigenous marine bacteria by natural transformation. Plasmid DNA from the transformants had altered restriction profiles. However, with the exception of the EcoRI site from one transformant (BS10), fragments amplified by polymerase chain reaction (PCR) and encompassing the recognition sites were cleaved by the relevant endonucleases, providing the sites were present. Analysis with DpnI and MboI indicated differences in DNA methylation between pQSR50 and the transformants. The missing EcoRI site from BS10 and smaller EcoRI fragments observed in transformants indicated that rearrangements had also occurred. Evolution of novel plasmid molecules following gene transfer may be an important mechanism by which natural genetic diversity is generated.

Spectral characteristics of postural control in elderly individuals

OBJECTIVE

To examine the feasibility of using spectral analysis techniques to identify potential biomarkers of diminished postural control in elderly individuals.

DESIGN

Data from spectral signatures (derived from postural sway) of 21 young adults and 42 elderly individuals classified as "high" or "low" risk with regard to functional balance capacity were analyzed using Risk Category (3) x Sensory Condition (3) multivariate analyses of variance. Postural control was challenged by varying the visual conditions under which individuals stood on a measurement platform.

RESULTS

Results indicated that measures of central tendency and dispersion of the spectral frequency distribution from medial-lateral components of sway (but not antero-posterior sway) clearly differentiated between "high" and "low" risk elderly. Low risk elderly were not different from young adults. High risk elderly exhibited greater dispersion and lower mean frequency than other groups.

CONCLUSIONS

Differences in spectral characteristics of medial-lateral components of sway were more related to risk category than to age. Elderly persons with high functional balance capacity displayed characteristics similar to those of young adults. Thus, spectral frequency analysis techniques may be a clinically useful tool for identifying individuals potentially at risk of falling.

The naturally transformable marine bacterium WJT-1C formally identified as "Vibrio" is a pseudomonad

A marine bacterial isolate, previously identified as Vibrio WJT-1C (ATCC 55351) and used as a model for investigating the process of natural transformation in the marine environment, has been further examined to determine its taxonomic identity. API 20E test strips, phenotypic testing, and flagellar staining had previously assigned the strain to the genus Vibrio, most closely related to V. campbelli. 16S rRNA analysis indicated that WJT-1C was in the Pseudomonas subgroup of the gamma proteobacteria. Bacteriophage typing and natural transformation with chromosomal DNA indicated that it was distinct from previously described marine transforming pseudomonads including Pseudomonas stutzeri strain JM300. The importance and abundance of the Pseudomonas subgroup of the gamma proteobacteria in the environment suggest that these marine strains are well suited as model organisms for describing the process and importance of natural transformation in nature.

Natural transformation in river epilithon

Natural transformation was demonstrated in unenclosed experiments incubated in river epilithon. Strains of Acinetobacter calcoaceticus were transformed to prototrophy by either free DNA (lysates) or live donor cells. The sources of transforming DNA and recipient culture were immobilized on filters, secured to stones, and incubated midstream in the river. The transfer frequency generally increased with temperature. No transfer was detected in the river Taff below 10 degrees C. The age of the recipient culture affected the transformation frequencies in situ but did not significantly affect the transfer frequency on laboratory media. Transformation of recipient cultures which had been incorporated into the natural epilithic biofilm and transformation of the plasmid pQM17 in situ were also demonstrated. This study provides the first direct evidence of natural transformation in situ of bacteria incorporated into an indigenous community.

Age-related differences in timing control of repetitive movement: application of the Wing-Kristofferson model

Age differences in timing control were investigated in persons between 6 and 75 years. Subjects performed a repetitive finger-tapping task, attempting to match a 550-ms interresponse interval (IRI). Response variability was analyzed using the method of Wing-Kristofferson (1973). An autocovariance technique estimated the proportion of the overall (total) IRI variability contributed by central (clock) and peripheral implementation (motor delay) processes. Significant age and gender differences were revealed only for total and clock variability. Results indicated that (a) young children (6-7 years) had higher variances than all other age groups, (b) older children (9-10 years) were more variable than young and middle-age adults, (c) variances did not differ significantly across three adult age groups (21-75 years), and (d) males were less variable than females for all age groups. In agreement with recent investigations that have used the Wing-Kristofferson methodology, this study suggests that age-related differences in timing control are largely a function of central processes.

Timing and Motor Control in Clumsy Children

The study examined timing control in clumsy children and employed the Wing-Kristofferson (1973) model of repetitive movements in an attempt to identify the locus of timing control difficulties in clumsy children. Two groups of children classified as normal and clumsy (ages 6-7 and 9-10) performed tapping and perception of duration and loudness tasks. Results indicated that clumsy children were significantly more variable than normal children in maintaining a set rate of tapping and in accurately judging time intervals. Evidence indicated that the source of timing control problems in clumsy children may be in a central timekeeping mechanism, possibly the cerebellum.

Effects of DDAVP on movement planning and execution processes in the healthy elderly

Effects of DDAVP on speed and consistency of planning and executing simple and complex movements in healthy older adults were studied. A simple reaction time (SRT) task, a single-plane movement task, and two tasks involving multiplane movements of distal upper extremities were performed with and/or without a 0.6 ml intranasal dose (60 micrograms) of DDAVP or placebo. Results indicated that DDAVP had no significant effect on speed or consistency of SRT processes, or the speed with which simple or complex movements were planned or executed. There was also no effect on retention of motor responses.

Effects of DDAVP on movement planning and execution processes in healthy young adults

This study investigated the effects of an acute dose of DDAVP on speed and consistency of planning and execution of simple and complex movements in healthy young adults. A simple reaction time task (SRT), a simple movement task (SMT), and a complex movement task (CMT) were performed with and without a 0.6 ml intranasal dose (60 micrograms) of DDAVP. Results indicated DDAVP-treated individuals planned and executed CMT and SRT tasks faster and more consistently than did placebo-treated subjects. There were nonsignificant DDAVP effects on speed and variability of both RT and MT processes involved in the SMT.

Lost in the wash

I started to read Paul Elliot's cover article (Nursing Standard week ending June 3) on infection control entitled 'To wash or not to wash?' in keen expectation that he would answer his own question and tell us when, for how long and in what way we should wash our hands to minimise cross infection.

Duration of muscle activity during standing in normally and slowly developing children

Research in motor control indicates that there are fixed patterns of activity which occur in certain muscle groups involved in standing in adults. The purpose of this study was to assess patterns of duration of muscle activity during quiet standing with and without superimposed arm movement in young children with normal and delayed motor development. Thirty-three children 4, 6, 8 and 10 years of age were screened for level of motor development and classified as either normally or slowly developing. Children performed two tasks: standing and standing with a superimposed 90 degree shoulder abduction movement. Using surface electrodes, EMG activity was monitored in Gastrocnemius, Tibialis Anterior and Erector Spinae muscle groups. The percentage of time activity was present in individual muscle groups was analyzed as a function of age and developmental level. Results indicated that quiet standing in children with delayed motor development was characterized by greater duration of activity in trunk than in leg muscles while in normal children, there was a more equal distribution of muscle activity between the legs and trunk. Both groups of children accommodated superimposed arm movement by increasing the percentage of time Erector Spinae activity was present. Patterns of duration of muscle activity in the legs were, however, different for the two groups of children.

Development of movement schema in young children

To examine the development of movement schema in young school-age children, i.e., whether principles which govern fine eye-hand coordination skill learning as suggested by Schmidt's schema theory apply to the learning of gross motor skills Exp. 1 involved 48 right-handed first-grade children. On a modification of the Fitts Reciprocal Tapping task children moved a stylus (held in the hand or attached to a special shoe worn on the foot) between two metal targets separated by different distances. Children were randomly assigned to one of eight groups: two control or no-practice groups and six experimental or transfer groups. A one-way analysis of variance followed by appropriate Scheffé post hoc tests indicated that movements of the lower limbs were not organized into a movement schema, but a pattern of schema of movement for the upper limbs developed. That no movement schema developed for lower limb movements suggests development of movement schema is intricately linked to both the existing as well as the potential for developing precise movement in those limbs. Exp. 2 involved 40 first-grade children who were randomly assigned to perform a gross-motor agility task under one of three conditions: direct practice on the criterion task, constant practice on a modification of the criterion task, or variable practice on several different modifications of the criterion task. A groups X trials analysis of variance with appropriate post hoc tests indicated that there were no significant differences among direct, constant, or variable practice groups. Data suggest that the amount of practice may be as important as the type of practice in developing movement schema involved in gross motor skills in young children.

Descriptive analysis of static postural control in 4, 6, and 8 year old normal and motorically awkward children

The purpose of the study was to analyze static postural control in 4, 6, and 8 year old normally and slowly developing children using qualitative electromyographic (EMG) techniques. Fourteen normally developing and six motorically awkward children performed seven different static balance tasks; twelve different muscle groups were monitored electromyographically. Results indicated that average amplitude of EMG activity involved in static postural task performance decreased with increasing age for normally developing children. Motorically awkward children displayed greater amounts of muscular activity in task performance than did normal children of similar chronological ages. Muscle activity profiles of motorically awkward children were clearly unlike those of normally developing children. The suggestion is made that one of the important characteristics of neuromuscular development in normal children is a gradual refinement of both localization and level of muscle activity.

Hemispheric specialization in normally and slowly developing children: a tachistoscopic and dichaptic evaluation

The purpose of the study was a description of hemispheric specialization characteristics of normally developing right- and left-handed children and determination of what differences in such characteristics, if any, existed between young normally developing and older slowly developing children. With dichaptic and tachistoscopic methods, hemispheric specialization characteristics of 15 slowly developing children (5-0 to 9-6 yr.) and 25 normally developing children (6-0 to 6-11 yr.) were assessed. Latencies and the number of correct responses were analyzed. Both right- and left-handed normally developing 6-yr.-olds showed considerable evidence of bilateralization of hemispheric functions for spatial and verbal information processing; slowly developing children exhibited unusual patterns of hemispheric specialization usually opposite those typically expected in children or adults. Response latency measures of performances of slowly developing children suggested a bilateralization of hemispheric function for processing of verbal and spatial information; number of correct responses indicated that lateralization of such functions was present.

Prediction of later cognitive behavior from early school perceptual-motor, perceptual, and cognitive performances

Multiple regression equations were generated to predict cognitive achievement for 189 young children (ages 57 to 92 mo.) 1 yr. after original administration of a battery of perceptual-motor, perceptual, and cognitive tests. Regression equations generated from maximum R2 improvement techniques indicated that a battery of perceptual and perceptual-motor performances at pre-kindergarten is useful for prediction of cognitive performance 1 yr. later at kindergarten level. This battery included one fine and two gross perceptual-motor tasks, and one visual and two auditory perceptual tasks. Inclusion of original cognitive performances did not improve the optimal prediction equation for this age group. In contrast, cognitive achievement at first grade and, particularly, at second grade levels was best predicted from knowledge of earlier cognitive performances.

A test battery to assess intrasensory and intersensory development of young children

The purpose of the study was to develop a battery of tests for use in evaluation of intra- and intersensory development of young children. A battery of 15 tests (4 visual, 4 auditory, 4 tactile-kinesthetic, and 3 intersensory) was administered to 109 normally developing 6- and 8-year-old and 32 slowly developing or learning disabled children. Interdependence of test items within each intrasensory and the intersensory category was determined; intercorrelations ranged from .00 to .78. Reliability estimates were also determined. Face validity was claimed for each item. The effects of age or developmental level on test performance were established. Based upon the interdependence of the tests, reliability estimates, and the capacity of the tests to discriminate among groups classified according to age or developmental level, a battery of 10 intra- and intersensory tests was proposed. The battery has 3 tests of visual perception-visual memory, dynamic depth perception, and size discrimination; 3 tests of auditory perception-auditory discrimination, auditory memory of related syllables, and auditory sequential memory of numbers; 2 tests of tactile-kinesthetic perception-tactile integration and movement awareness; and 2 tests of intersensory integration-auditory-tactile intergration and auditory-visual integration.

Rate and Level of Learning as Functions af Information-Processing Characteristics of the Learner and the Task

This study examined relationships among information-processing characteristics of the learner, dominant information-processing component of tasks, and the rate and level of mastery of selected motor tasks. Sixth grade children (n=60) were classified as high, moderate, or low visual and/or proprioceptive information processors and asked to learn a fine perceptual-motor task and one of two gross perceptual-motor tasks that differed in the relative importance of visual and proprioceptive components. When visual and proprioceptive demands of a task were equivalent, high information processors showed higher levels of task mastery than low information processors; when proprioceptive tasks demands were dominant, results were equivocal. If processing demands were high, high proprioceptive information processors exhibited higher performance than did low subjects. When demands were less, performance level was not significantly affected. Rate of task mastery was never affected by these factors.

A comparison of selected behaviors of identical twins, one blind from birth

The purpose of this study was to compare differences in mental-emotional, fine perceptual-motor and gross motor behaviors of a set of 13 year-old identical twins, one of whom was blind from birth. In general, the blind twin was superior in performances where total body involvements were minimal and fine manipulative movements of the hands and/or fingers were stressed. The blind twin also appeared to be more well-adjusted emotionally than the sighted twin.

Accuracy of facing movements executed without vision

58 university-age men and women were blindfolded and ear-plugged and asked to execute facing movements of 90°, 180°, and 360°. 90° turns were overestimated, while 180° and 360° turns were underestimated. The accuracy of judgments on this task depended upon the individual making the turn, the direction in which the facing movement was made, and the magnitude of the turn requested.