Biomedical subjects

J Perry

Publications and source records attributed to J Perry.

At least 91 records · Page 5Linked to original sources

PubMed1998

Service support to people in Wales with severe intellectual disability and the most severe challenging behaviours: processes, outcomes and costs.

A survey of people with severe intellectual disability and the most severe challenging behaviour in Wales identified five adults living in family homes, 17 in new specialist community housing and 19 in traditional services. With the omission of two people from the latter group and with a restricted collection of data for people living in the family home, the present study explored service input, outcome and costs across the three setting types. Process and outcome indicators for the family home group, who received little service input, were better than those for the traditional service group, although less good than those for the community house group. The specialist community home model produced significant gains over the traditional services in virtually all areas. Across the residential data set as a whole, there was no association between staff:resident ratios and severity of disability or between costs and severity of disability. This was largely true of the service types separately. There was a relationship between costs and service quality. However, this association was underpinned by gross differences between community houses and traditional settings. Costs, processes and outcomes ceased to be related when the two residential types were considered separately. Although higher costs of new community services compared to traditional services may be set against improved outcomes, high costs within the former could not be related to benefit. Outcome indicators were generally related to each other, suggesting that high quality in one sense was matched by high quality in other senses. Outcome was significantly associated with the ability of residents. Outcome indicators also tended to be related to observed staff performance, which was independent of resident ability. Therefore, outcome may be considered as dually determined by differences in resident ability and in what staff did.

Adult↗

PubMed1998

The characteristics and residential situations of people with severe intellectual disability and the most severe challenging behaviour in Wales.

A total population study of people in Wales with severe intellectual disability and the most severe challenging behaviour was undertaken to identify their characteristics, and the nature of their residential arrangements and service support. Forty-one participants were identified: five living in family homes, 17 in community housing, 17 in hospitals and two in hostels. The family home group had slightly higher adaptive behaviour scores than residents in community housing. Both groups had significantly higher scores than the hospital and hostel residents combined. Assessments of challenging behaviour showed the groups to be similar and to have a considerable range and extent of severely problematic behaviour. Co-occurrence of several forms of frequent severe problem behaviour was the norm and there was a marked association with social impairment. The five people living in their family homes had nominated service keyworkers, but reported professional input was low. The residential situations comprised two main service types: (1) traditional services, which were characterized by large living unit and facility size, atypical architectural design, relative isolation from the community, a greater level of buildings adaptations, low staff:resident ratios, a relatively high percentage of qualified staff, and a relative absence of systematic approaches to goal planning and structured activity; and (2) new community houses, which were characterized by small size, domestic design, location within the community, a lower level of buildings adaptations, much higher staff:resident ratios, and less emphasis on qualified staff but a greater emphasis on systematic working methods. Community settings were similar in having 'specialist' resident groupings based on challenging behaviour or conditions like autism in which challenging behaviours are common. A policy to provide for people with these characteristics being resettled from traditional settings in this way seems to have been established.

Adult↗

PubMed1998

The human FXY gene is located within Xp22.3: implications for evolution of the mammalian X chromosome.

It has been proposed that the pseudoautosomal region of mammals has evolved by sequential addition of autosomal material onto the X and Y chromosomes followed by movement of the pseudoautosomal boundary to create X-unique regions. We have previously described a gene, Fxy , that spans the pseudoautosomal boundary in mice such that the first three exons of the gene are located on the X chromosome, but the remainder of the gene is located on both X and Y chromosomes. Therefore, this gene might be in a state of transition between pseudoautosomal and X-unique locations. In support of this theory we show here that the human FXY gene is located in Xp22.3 in humans, proximal to the pseudoautosomal boundary.

Amino Acid Sequence↗

PubMed1998

Shoulder joint kinetics during the push phase of wheelchair propulsion.

The purpose of this investigation was to quantify the forces and moments at the shoulder joint during free, level wheelchair propulsion and to document changes imposed by increased speed, inclined terrain, and 15 minutes of continuous propulsion. Data were collected using a six-camera VICON motion analysis system, a strain gauge instrumented wheel, and a wheelchair ergometer. Seventeen men with low level paraplegia participated in this study. Shoulder joint forces and moments were calculated using a three-dimensional model applying the inverse dynamics approach. During free propulsion, peak shoulder joint forces were in the posterior (46 N) and superior directions (14 N), producing a peak resultant force of 51 N at an angle of 185 degrees (180 degrees = posterior). Peak shoulder joint moments were greatest in extension (14 Newton-meters [Nm]), followed by abduction (10 Nm), and internal rotation (6 Nm). With fast and inclined propulsion, peak vertical force increased by greater than 360%, and the increase in posterior force and shoulder moments ranged from 107% to 167%. At the end of 15 minutes of continuous free propulsion, there were no significant changes compared with short duration free propulsion. The increased joint loads documented during fast and inclined propulsion could lead to compression of subacromial structures against the overlying acromion.

Acceleration↗

PubMed1998

The DNA sequence of equine herpesvirus-4.

The complete DNA sequence of equine herpesvirus-4 (EHV-4) strain NS80567 was determined. The genome is 145597 bp in size and consists of a long unique region (UL, 112398 bp) flanked by a short inverted repeat (TRL/IRL, 27 bp) linked to a short unique region (Us, 12789 bp) flanked by a substantial inverted repeat (TRs/IRs, 10178 bp). EHV-4 is predicted to contain 76 different genes; three of these are present twice in TRs/IRs, giving a total of 79 genes. The closely related virus equine herpesvirus-1 (EHV-1) also possesses 76 different genes corresponding to those of EHV-4, but has a total of 80 genes because four are present twice in TRs/IRs. Interpretations of the coding capacity of the EHV-4 and EHV-1 genomes were refined by comparing the complete DNA sequences.

Amino Acid Sequence↗

PubMed1998

Segment velocities in normal and transtibial amputees: prosthetic design implications.

Dynamic elastic response foot and ankle prostheses (Seattle-Lite, Flex Foot, etc.) used by transtibial amputees feature substantial design improvements over conventional designs (SACH, Single Axis, etc.). Despite this progress, transtibial amputees continue to expend greater energy than normals. Increased residual limb EMG data and altered gait patterns suggest that impaired mobility may be the cause of overactive muscles in early stance. Prosthetic mobility was therefore quantified by measuring foot, shank and thigh velocities in nine transtibial amputees, wearing three different foot designs: Single Axis (SA), Seattle Lite (SL) and Flex Foot (FF). The magnitude, timing and rate of segment velocities for each prosthetic design, characterizing early stance mobility, were compared with corresponding measures in normal, nonamputee (NA) controls using Dunnett's test. Regardless of foot type, transtibial (TT) amputees walked slower than non amputee controls (63.3-65.8 m/min versus 78.5 m/min, p < 0.05) and their stride length was shorter (1.21-1.26 m versus 1.41 m, p < 0.01). In early stance, peak foot and shank velocities were lower (p < 0.01) for both the SL and FF while only shank velocity was lower (p < 0.01) with the SA compared to NA controls. Significant delays in the timing of early stance events such as peak shank velocity, peak ankle plantarflexion and peak knee flexion compromised shank and knee stability in TT amputees. Foot and shank mobility was uncontrolled with the SA design while ankle mobility was restricted by the FF and SL feet. In NA controls on the other hand, appropriate timing and rate of segment velocity changes preserved dynamic stability and forward progression in early stance. This was evidenced by rapid decreases in foot and shank velocity as the thigh velocity increased during weight acceptance. Future prosthetic designs should provide TT amputees with improved ankle mobility that attempt to capture the dynamic characteristics of a normal articulation between the foot and shank segments during the early stance weight acceptance period.

Amputation, Surgical↗

PubMed1998

The Y* rearrangement in mice: new insights into a perplexing PAR.

In essence, the Y* rearrangement in the mouse is a Y chromosome that has been hijacked by a non-Y centromere attached distal to the pseudoautosomal region (PAR). All the Y-unique material is thought to be unaltered, but the recombinatory behaviour of the Y* with the X during male meioisis led to the conclusion that part of the PAR is inverted. In the course of a cross set up to introduce the X-linked mutation Patchy fur (Paf) into XY* males, the Y* chromosome was found to carry the wild type allele of Paf. Paf maps close to the X PAR boundary, so we hypothesised that the inverted region of the Y* PAR originated from an X chromosome that provided not only an inverted copy of proximal PAR, but also an X PAR boundary together with some adjacent X-unique material that included the Paf locus. This hypothesis was validated by Southern analysis using an X PAR boundary probe to show that Y* has an X PAR boundary. Thus the Y* PAR has resulted from an end to end fusion of an X and a Y PAR. Furthermore, it was shown that in conjunction with this PAR-PAR fusion, there has been deletion of both copies of the distally located pseudoautosomal gene Steroid sulfatase (Sts).

Animals↗

PubMed1998

Assessment of rearfoot motion: passive positioning, one-legged standing, gait.

Earlier studies that address assessment of the subtalar joint (STJ) by measuring rearfoot motion used a goniometer to evaluate intertester reliability. Few investigations have determined how positions of the rearfoot, assessed manually (passive range of motion) or statically in one-legged standing, compare with those occurring during walking. The purpose of this study was to determine the following: (1) the intertester reliability of positioning the STJ in neutral, maximum inversion, and maximum eversion; (2) the reliability of the rearfoot position during relaxed one-legged standing; and (3) how these positions compare to rearfoot motion during walking. An electrogoniometer attached to the lateral aspect of the lower leg and heel was used to record the position of the rearfoot during testing procedures. Ten healthy volunteers participated. Rearfoot position was recorded during relaxed one-legged standing and during free and fast walking. Additionally, rearfoot position was recorded while each of three physical therapists positioned the STJ in neutral, maximum inversion, and maximum eversion. Intertester reliability for positioning the STJ in neutral, maximum inversion, and maximum eversion yielded intraclass correlation coefficients of 0.76, 0.37, and 0.39, respectively. Reliability of relaxed one-legged standing had an intraclass correlation coefficient of 0.92. The rearfoot position in relaxed one-legged standing and the maximum eversion position occurring during gait were not significantly different. These findings suggest that there is good intertester reliability in positioning the STJ in neutral. Additionally, the rearfoot position in relaxed one-legged standing may be used to approximate the maximum eversion position that occurs during gait.

Adult↗

PubMed1997

A gene spans the pseudoautosomal boundary in mice.

The X and Y chromosomes of the mouse, like those of other mammals, are heteromorphic over most of their length, but at the distal ends of the chromosomes is a region of sequence identity, the pseudoautosomal region (PAR), where the chromosomes pair and recombine during male meiosis. The point at which the PAR diverges into X- and Y-specific sequences is called the pseudoautosomal boundary. We have completed a genomic walk from the X-specific Amelogenin gene to the PAR. Analysis of this region revealed that the pseudoautosomal boundary of mice is located within an intron of a transcribed gene that encodes a novel RING finger protein. The first three of the exons of the gene are located on the X chromosome whereas the 3' exons of the gene are located on both X and Y chromosomes. This unusual arrangement may indicate that the gene is in a state of transition from pseudoautosomal to X-unique and provides evidence for a process of attrition of the pseudoautosomal region on the Y chromosome.

Amelogenin↗

PubMed1997

A knee simulating machine for performance evaluation of total knee replacements.

A knee simulating machine is required for the design and evaluation of total knee replacements, the kinematics and the long-term wear being aspects of particular importance. There are no generally agreed design criteria, such that existing designs of simulator have a wide variety of input and constraint conditions. In this study, it was postulated that in order to reproduce physiological wear patterns, the correct kinematics is required, on the basis that the wear will be a direct function of the sliding, rolling and tractive rolling conditions at the joint surfaces. In turn, the correct kinematics would only be achieved by the input of physiological forces, by the appropriate constraints on the fixtures holding the components, and by simulating the soft tissue restraints. A knee simulating machine based on these principles was constructed, and used to test the kinematics of a range of contemporary condylar replacement knees. The displacements and rotations varied over a range of almost two times, even with the soft tissue restraints. Without the restraints, the low constraint designs would have dislocated or moved unrealistically. It was concluded that a simulating machine should be based on the input of forces and moments, rather than on displacements and rotations, in order to provide data of kinematics and wear.

Biomechanical Phenomena↗

PubMed1997

Are patellofemoral pain and quadriceps femoris muscle torque associated with locomotor function?

BACKGROUND AND PURPOSE: The purpose of this investigation was to determine the influence of pain and muscle weakness on gait variables in subjects with patellofemoral pain (PFP). SUBJECTS: Nineteen female subjects with a diagnosis of PFP and 19 female subjects without PFP participated in the study. METHODS: Subjects underwent gait analysis (stride characteristics and joint motion) during level walking, ascending and descending stairs, and ascending and descending ramps, in addition to isometric torque testing of the knee extensors of the involved limb. Pain and functional status also were assessed. RESULTS: Compared with the comparison group, the primary gait compensation in the PFP group was a reduced walking speed, which was a function of both a reduced stride length and cadence. Knee extensor torque was the only predictor of gait function, with increased torque correlating with improved stride characteristics. In addition, PFP was not associated with locomotor function. CONCLUSION AND DISCUSSION: These findings suggest that functional ability in persons with PFP is associated with increased quadriceps femoris muscle torque. Future research is needed to determine whether function improves with quadriceps femoris muscle strengthening.

Adolescent↗

PubMed1997

Prosthetic weight acceptance mechanics in transtibial amputees wearing the Single Axis, Seattle Lite, and Flex Foot.

Loading response challenges the limb with the dual demands of accepting rapidly moving body weight to both absorb the shock of floor contact and create a stable limb over which the body can advance. Delay in achieving foot flat contact with the floor causes a prolonged period of heel only support and results in an unstable base of support for those persons with transtibial amputations. The purpose of this study was to identify mechanical causes of instability during weight acceptance with three different prosthetic foot designs, Single Axis, Seattle Lightfoot, and Flex Foot. Ten male individuals with transtibial amputations were tested on three separate occasions wearing each prosthetic foot. A comparison group of ten individuals without transtibial amputations was also examined. Mean free walking speed was significantly slower for those with transtibial amputations regardless of the prosthetic foot worn (p < 0.05). Contralateral toe off times were significantly later for each prosthetic foot (p < 0.01). The timing of peak knee flexion was found to be significantly later than normal for each prosthetic foot (p < 0.01). To minimize the impact of initial floor contact, persons with an intact limb used rapid plantar flexion, followed by a slower lowering of the foot to the floor. Dorsiflexion then stimulated knee flexion and foot flat. Two altered functions were found for all three prosthetic feet, reduced knee flexion and prolonged heel only support. Diminished knee flexion reflected delayed dorsiflexion and tibial advancement as a result of the cushioned heel. Lateness in reaching foot flat was also found. To improve the walking abilities of those persons with transtibial amputations, prosthetic foot designs need to incorporate mechanisms which promote early foot flat while preserving limb stability.

Aged↗

PubMed1997

A PASS 3 evaluation of community residences in Wales.

PASS 3 was used to evaluate 14 residential services for people with mental retardation. Residents had a broad range of abilities. Size of residences ranged from one to seven residents. PASS scores were generally associated with both resident's ability level and smaller size of living unit. Overall, the residences were shown to be well-located and reasonably home-like. However, residence personnel tended to lack organized means and competencies to promote resident development and experience. Administrative practices were also weak. Attention must be given to factors other than residence size, location, building characteristics, and staffing parameters when services are commissioned and when service contracts are specified and reviewed.

Adult↗

PubMed1997

The ability of male and female clinicians to effectively test knee extension strength using manual muscle testing.

It has been suggested that the accuracy of manual muscle testing is dependent on examiner strength. Our purpose was to relate male and female clinicians' upper extremity strength to their ability to challenge the quadriceps and detect weakness in patients using manual muscle testing. Quadriceps muscles of seven men and 12 women with postpoliomyelitis were tested manually by a male and female clinician while forces were recorded with a hand-held dynamometer. Patients' maximal isometric knee extension force was recorded with a Lido dynamometer and clinicians' maximal vertical push force was recorded with the hand-held dynamometer. Manual muscle testing forces, patient maximum quadriceps forces, and examiner push forces were compared with repeated measures analysis of variance. Female examiners' maximal vertical push force (235.7 +/- 54.3 N) was not significantly different from either female or male patients' maximal quadriceps force (166.8 +/- 66.7 N and 341.6 +/- 123.7 N) but was only 60% and 40% of the isometric knee extension forces generated by a group of normal women and men. Male examiners were significantly stronger (357.0 +/- 93.4 N) than the female but not the male patients and produced 90% and 60% of the normal isometric quadriceps forces for women and men. Examiners gave appropriate grades in 30 of 38 tests. Examiner strength limits detection of moderate quadriceps weakness with manual resistance. Most of the muscle test grades, however, were appropriate, given the examiner's upper extremity strength. Clinicians using manual muscle testing should determine their maximal vertical push force and the extent of weakness they can detect.

Exercise↗

PubMed1997

The effects of patellar taping on stride characteristics and joint motion in subjects with patellofemoral pain.

Although patellar taping has been reported to be effective in reducing pain, the effects of this procedure on functional outcomes, such as ambulation, have not been documented. The purpose of this study was to compare stride characteristics and joint motion in subjects with patellofemoral pain, with and without the application of patellar taping using the McConnell technique. Fifteen female subjects between the ages of 14 and 41 years with diagnosis of patellofemoral pain participated in this study. Stride characteristics (Stride Analyzer) and sagittal plane joint motion (VICON) were recorded simultaneously during taped and untaped trials of free walking, fast walking, and ascending and descending a ramp and stairs. A repeated measures analysis of variance was used to determine differences between taped and untaped trials. Although subjects reported an average pain reduction of 78% using a visual analogue scale, the only significant change in stride characteristics was an increase in stride length during ramp ascent. Patellar taping did, however, result in a small but significant increase in loading response knee flexion across all conditions tested. We believe this finding demonstrates more willingness by the patellofemoral pain subjects to load the knee joint, thus permitting increased shock absorption, increased quadriceps activity, and tolerance of increased patellofemoral joint reaction force.

Adolescent↗

PubMed1997

Stair ambulation in persons with transtibial amputation: an analysis of the Seattle LightFoot.

The purpose of this study was to document gait patterns in a group of individuals with transtibial amputations (TTA) during stair ambulation, and to identify the functional limitations associated with this task. Ten persons with TTA fitted with a Seattle LightFoot prosthetic component, and 14 nondisabled subjects participated in this study. Electromyographic activity (EMG) of the vastus lateralis (VL), rectus femoris (RF), gluteus maximus (GMAX), semimembranosus (SMEMB), biceps femoris long head (BFLH), and biceps femoris short head (BFSH) was assessed using indwelling wire electrodes during ascending and descending stairs. Lower limb kinematics (VICON) and stride characteristics (Footswitch Stride Analyzer System) also were collected. Stride characteristics revealed that those with TTA had a significantly slower rate of stair ambulation and demonstrated stance phase asymmetry between limbs compared to the nondisabled. Kinematic analysis determined significant limitations in prosthetic ankle motion, which necessitated compensatory functions at the hip and knee to accomplish stair ascent and descent and resulted in significantly greater muscular effort (increased EMG intensity and duration) compared to nondisabled.

Adult↗

PubMed1996

Structural variation of the pseudoautosomal region between and within inbred mouse strains.

The pseudoautosomal region (PAR) is a segment of shared homology between the sex chromosomes. Here we report additional probes for this region of the mouse genome. Genetic and fluorescence in situ hybridization analyses indicate that one probe, PAR-4, hybridizes to the pseudoautosomal telomere and a minor locus at the telomere of chromosome 9 and that a PCR assay based on the PAR-4 sequence amplifies only the pseudoautosomal locus (DXYHgu1). The region detected by PAR-4 is structurally unstable; it shows polymorphism both between mouse strains and between animals of the same inbred strain, which implies an unusually high mutation rate. Variation occurs in the region adjacent to a (TTAGGG)n array. Two pseudoautosomal probes can also hybridize to the distal telomeres of chromosomes 9 and 13, and all three telomeres contain DXYMov15. The similarity between these telomeres may reflect ancestral telomere-telomere exchange.

Animals↗

PubMed1996

Electromyographic analysis of the shoulder muscles during depression transfers in subjects with low-level paraplegia.

OBJECTIVE: To document and compare the intensity of selected shoulder muscle activity during depression transfers. DESIGN: Intramuscular electrodes were used to record the activity of 12 shoulder muscles while transferring to and from a wheelchair. PARTICIPANTS: Twelve adult men with spinal cord injuries resulting in low paraplegia. OUTCOME MEASURES: Three phases of the transfer were analyzed: preparation, lift, and descent. Median intensities were compared between muscles, transfer phase, and direction of transfer using Freidman's test. RESULTS: Trunk elevation was accomplished mainly by sternal pectoralis major and latissimus dorsi activity. Lateral body displacement required other muscles to control the elevated body. Rotator cuff muscles contributed to shift mechanics and, together with anterior deltoid, provided anterior glenohumeral wall protection. Lower serratus anterior stabilized the scapulothoracic articulation and contributed to the lateral movement. CONCLUSIONS: Assessment of depression transfer skill should not be based on the ability to lift body weight. Movement of the trunk required vigorous activity of key shoulder musculature. Differences in leading and trailing arm EMG intensities will assist in modifying transfer style in individuals with weakness, strength imbalances, and shoulder pathologies.

Adult↗