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Biomedical subjects

J Perry

Publications and source records attributed to J Perry.

At least 19 recordsLinked to original sources
PubMed2006

Cassini observes the active south pole of Enceladus.

Cassini has identified a geologically active province at the south pole of Saturn's moon Enceladus. In images acquired by the Imaging Science Subsystem (ISS), this region is circumscribed by a chain of folded ridges and troughs at approximately 55 degrees S latitude. The terrain southward of this boundary is distinguished by its albedo and color contrasts, elevated temperatures, extreme geologic youth, and narrow tectonic rifts that exhibit coarse-grained ice and coincide with the hottest temperatures measured in the region. Jets of fine icy particles that supply Saturn's E ring emanate from this province, carried aloft by water vapor probably venting from subsurface reservoirs of liquid water. The shape of Enceladus suggests a possible intense heating epoch in the past by capture into a 1:4 secondary spin/orbit resonance.

Extraterrestrial Environment↗
PubMed2006

The activity of methylated and non-methylated selenium species in lymphoma cell lines and primary tumours.

BACKGROUND: Diffuse large B-cell lymphoma patients with low serum selenium concentration at presentation have a lower response rate and overall survival than patients with higher serum selenium. The co-administration of selenium with conventional chemotherapy may be useful in these patients. PATIENTS AND METHODS: We investigated the activity of two selenium species, methylseleninic acid (MSA) and selenodiglutathione (SDG) in a panel of human lymphoma cell lines and in a primary lymphoma culture system. RESULTS: Both compounds demonstrated cytostatic and cytotoxic activity with EC(50) values in the range 1.0-10.2 microM. Cell death was associated with an increase in the sub-G1 (apoptotic) fraction by flow cytometry and was not preceded by any obvious cell cycle arrest. SDG, but not MSA, resulted in marked increases in intracellular ROS, particularly in CRL2261 and SUD4 cells in which the cytotoxic activity of SDG was partly, or completely, inhibited by n-acetyl cysteine, suggesting a dependence on ROS for activity in some cells. Both MSA and SDG showed a concentration dependent reduction in percentage viability after a 2-day exposure in primary lymphoma cultures, with EC(50) values in the range 39-300 microM and 9-28 microM, respectively. CONCLUSION: The selenium compounds MSA and SDG induce cell death in lymphoma cell lines and primary lymphoma cultures, which with SDG may be partly attributable to the generation of ROS.

Apoptosis↗
PubMed2006

Highly constrained backprojection for time-resolved MRI.

Recent work in k-t BLAST and undersampled projection angiography has emphasized the value of using training data sets obtained during the acquisition of a series of images. These techniques have used iterative algorithms guided by the training set information to reconstruct time frames sampled at well below the Nyquist limit. We present here a simple non-iterative unfiltered backprojection algorithm that incorporates the idea of a composite image consisting of portions or all of the acquired data to constrain the backprojection process. This significantly reduces streak artifacts and increases the overall SNR, permitting decreased numbers of projections to be used when acquiring each image in the image time series. For undersampled 2D projection imaging applications, such as cine phase contrast (PC) angiography, our results suggest that the angular undersampling factor, relative to Nyquist requirements, can be increased from the present factor of 4 to about 100 while increasing SNR per individual time frame. Results are presented for a contrast-enhanced PR HYPR TRICKS acquisition in a volunteer using an angular undersampling factor of 75 and a TRICKS temporal undersampling factor of 3 for an overall undersampling factor of 225.

Algorithms↗
PubMed2006

Quality of life in adults with an intellectual disability: the Evaluation of Quality of Life Instrument.

BACKGROUND: The construct of quality of life (QoL) has been the focus of a great deal of recent research and has been operationalized in the assessment of the effectiveness of biomedical and rehabilitative interventions. Consequently, the effective measurement of QoL has become a relevant issue. QoL assessment should take account of both objective life conditions and reported satisfaction with those conditions, and should recognize that QoL has multiple domains. There is also evidence to suggest that it is useful to supplement such assessments with the evaluations of significant others within a multidimensional assessment perspective. METHODS: The current study describes a further stage of testing and refinement of the Evaluation of Quality of Life Instrument (EQLI), which was designed to elicit from staff of health and social care services assessments of the level of satisfaction experienced by adults with an intellectual disability. Specifically, the EQLI's internal consistency, and construct, convergent and discriminant validity were analysed. RESULTS: The EQLI appears to be a psychometrically valid measure for collecting data on the levels of satisfaction which, according to health and social services staff, might be experienced by individuals with an intellectual disability who attend residential institutions and community-based day centres. The factor analyses supported a three-factor structure for the EQLI and reliability estimates of scores on the three factors were in the moderate to high range. The data collected supported convergent and discriminant validity. CONCLUSIONS: The results indicate that the EQLI is an effective measure for gaining staff perceptions of individuals who may be at risk of dissatisfaction with various QoL domains. The EQLI is as an instrument which, within a multidimensional assessment, could contribute to the identification of areas of user dissatisfaction with services.

Adolescent↗
PubMed2006

The value of T2 relaxation times to characterize lumbar intervertebral disks: preliminary results.

BACKGROUND AND PURPOSE: The present standard for staging intervertebral disk degeneration is a discrete scale, consisting usually of 5 stages. The purpose of this pilot study was to investigate the use of T2 measurements as a continuous measure of intervertebral disk degeneration. METHODS: We obtained images in 5 volunteers with a 3D fast spin-echo sequence modified for the purpose of calculating T2 relaxation times from multiple echoes in the echo train. Disks were classified on the basis of conventional criteria into one of the 5 stages of disk degeneration. Average T2 values were calculated for stage II, III, and V disks, which were identified in the volunteers. Differences between the disk levels were analyzed with analysis of variance and differences between stages tested with a Student t test with significance set at the 0.01 level. RESULTS: In the 5 volunteers, 20 stage II, 4 stage III, and a single stage V disk were found. Contour plots showed the highest T2 values in the nucleus pulposus near the vertebral endplates and lower T2 values in the intranuclear cleft region and peripheral annulus fibrosus. Average T2 values were significantly lower in the type III and V disks than in the normal disks. CONCLUSIONS: The study suggests that intervertebral disks can be characterized and classified accurately by means of T2 values. More studies are warranted to determine the range of T2 values for normal disks.

Adult↗
PubMed2005

Cassini Imaging Science: initial results on Saturn's atmosphere.

The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of approximately 375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a particularly active narrow southern mid-latitude region in which dark ovals are observed both to merge with each other and to arise from the eruptions of large, bright storms. Bright storm eruptions are correlated with Saturn's electrostatic discharges, which are thought to originate from lightning.

Atmosphere↗
PubMed2005

Cassini Imaging Science: initial results on Phoebe and Iapetus.

The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and has a mean density that is indicative of an ice-rock mixture. Iapetus's dark leading side (Cassini Regio) is ancient, heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief. Local albedo variations within and bordering Cassini Regio suggest mass wasting of ballistically deposited material, the origin of which remains unknown.

Extraterrestrial Environment↗
PubMed2005

Cassini Imaging Science: initial results on Saturn's rings and small satellites.

Images acquired of Saturn's rings and small moons by the Cassini Imaging Science Subsystem (ISS) during the first 9 months of Cassini operations at Saturn have produced many new findings. These include new saturnian moons; refined orbits of new and previously known moons; narrow diffuse rings in the F-ring region and embedded in gaps within the main rings; exceptionally fine-scale ring structure in moderate- to high-optical depth regions; new estimates for the masses of ring-region moons, as well as ring particle properties in the Cassini division, derived from the analysis of linear density waves; ring particle albedos in select ring regions; and never-before-seen phenomena within the rings.

Journal Article↗
PubMed2005

An EMG-to-force processing approach for determining ankle muscle forces during normal human gait.

Muscle forces move our limbs. These forces must be estimated with indirect techniques, as direct measurements are neither generally possible nor practical. An electromyography (EMG)-to-force processing technique was developed. Ankle joint moments and, by extension, ankle muscle forces were calculated. The ankle moment obtained by inverse dynamics was calculated for ten normal adults during free speed gait. There was close correlation between inverse dynamics ankle moments and moments determined by the EMG-to-force processing approach. Muscle forces were determined. The gait peak Achilles tendon force occurred in late single limb support. Peak force observed (2.9 kN) closely matched values obtained where force transducers were used to obtain in vivo muscle forces (2.6 kN). The EMG-to-force processing model presented here appears to be a practical means to determine in vivo muscle forces.

Adult↗
PubMed2005

Dietzia strain X: a newly described Actinomycete isolated from confluent and reticulated papillomatosis.

Confluent and reticulated papillomatosis (CRP) is a rare skin disorder. To date its aetiology remains uncertain. The possibility of an infectious aetiology has been supported by case reports of therapeutic response to antibiotic therapy. We have isolated and identified a previously unknown Dietzia strain, an Actinomycete, from skin scrapings of a 17-year-old boy with CRP. We propose that this organism may be the aetiological agent of CRP. Further investigations are necessary to determine the potential role of this Actinomycete in the pathogenesis of CRP.

Actinomycetales↗
PubMed2005

Correlation between subjective and objective measures of outcome in staffed community housing.

BACKGROUND: A distinction is made between objective and subjective assessment when quality of life evaluation is considered. The aim was to explore the association between objective and subjective appraisals within similar quality of life domains. METHODS: Correlations between scores on objective and subjective quality of life measures concerning choice, activity and integration were investigated by administering measures to the residents of a random sample of 47 small community housing services. Correlations between the measures and resident adaptive behaviour were also investigated. RESULTS: All objective measures were significantly correlated with adaptive behaviour but only one subjective measure was. With level of adaptive behaviour controlled, 6/7 correlations between pairs of objective measures were significant. Fifteen of the 16 correlations between objective and subjective measures were insignificant. CONCLUSIONS: Assessments of objective life conditions and personal satisfaction appear to be distinct. Their suitability for different purposes and the notion that subjective appraisal of life may be under homeostatic regulation are discussed.

Adaptation, Psychological↗
PubMed2004

Prevalence and clonality of Burkholderia cepacia complex genomovars in UK patients with cystic fibrosis referred for lung transplantation.

BACKGROUND: It has previously been reported that patients infected with Burkholderia cenocepacia (genomovar III) before lung transplantation have a poorer outcome than those with other B. cepacia complex infections. METHODS: An extensive study was conducted to determine the prevalence and clonality of B. cepacia complex genomovars isolated from patients referred for transplant assessment between 1989 to the present and, where appropriate, whether strain type was related to transplant outcome. RESULTS: Isolates from 29 patients were identified as B. cepacia complex organisms by molecular analysis. Thirteen patients (45%) were infected with the highly transmissible ET-12 strain of B. cenocepacia recA lineage III-A, while all remaining patients were infected with genetically unique B. cenocepacia, B. multivorans, and B. vietnamiensis strains. All previously reported deaths following transplantation were associated with ET-12 infection. CONCLUSIONS: The ET-12 strain is the predominant cause of B. cenocepacia infections in patients with cystic fibrosis referred to our pulmonary transplant centre and is associated with poor transplant outcomes using standard treatment regimens.

Burkholderia Infections↗
PubMed2003

Rocuronium versus succinylcholine for rapid sequence induction intubation.

BACKGROUND: Patients requiring emergent endotracheal intubation often require a rapid sequence induction intubation (RSI) technique to protect against gastric aspiration, to facilitate intubation, or to protect against increased intracranial pressure. Succinylcholine is the most common muscle relaxant used because it has a fast onset and a short duration. Unfortunately it can have serious side effects as a result of it's membrane depolarizing effect and release of potassium. Rocuronium has been suggested to create intubating conditions similar to succinylcholine. Previous studies have been underpowered to determine equivalence and there has been no previous meta-analysis performed. OBJECTIVES: To determine if rocuronium creates comparable intubating conditions to succinylcholine during RSI intubation. Comparisons were made with succinylcholine based on the dose of rocuronium, use of a narcotic, emergent versus elective intubation, age group and the induction agent used. The primary outcome was excellent intubation conditions. A secondary outcome of clinically acceptable conditions was also performed. These were all dichotomous outcomes using cutpoints from a four point scale by Goldberg to evaluate intubation conditions. SEARCH STRATEGY: We searched MEDLINE (1966-March 2000), EMBASE (1988-March 2000) and the Cochrane Central Register of Controlled Trials (CENRAL) (March 2000) for randomized controlled trials (RCT) or controlled clinical trials (CCT) relating to the use of rocuronium and succinylcholine. Foreign language journals were included. References of identified studies were hand-searched for citations missed by the electronic searches. SELECTION CRITERIA: All trials meeting the inclusion criteria (comparison of rocuronium and succinylcholine, one of study's main outcomes was scoring of intubation conditions) were included. DATA COLLECTION AND ANALYSIS: Data were extracted and methodological quality was assessed independently by two reviewers for allocation concealment. The outcomes were combined using MetaView 4.1 with risk differences for all categories and RR for the excellent outcomes with a random effects model. MAIN RESULTS: 40 studies were identified; 26 were combined for analysis. Overall, rocuronium was inferior to succinylcholine, with a RR=0.87 (95%CI = 0.81 to 0.94) (N=1606). In the group that used propofol for induction of anaesthesia, the intubation conditions were similar, with a RR=0.96 (95%CI = 0.87 to 1.06) (N=640). No major adverse events were reported. REVIEWER'S CONCLUSIONS: Succinylcholine created superior intubation conditions to rocuronium when comparing excellent intubation conditions. Using the less stringent outcome, clinically acceptable intubation conditions, the two agents were not statistically different. Intubation conditions were not statistically different between succinylcholine and rocuronium when propofol was used.

Androstanols↗
PubMed2003

Participants at the ASCCP 2000 Biennial Meeting adhere to published guidelines in their management of atypical squamous cells and atypical glandular cells on pap test.

OBJECTIVE: To determine practice patterns of the American Society for Colposcopy and Cervical Pathology (ASCCP) 2000 Biennial Meeting participants for management of women with atypical squamous cells of undetermined significance (ASCUS) and atypical glandular cells of undetermined significance (AGUS). MATERIALS AND METHODS: A three-page survey was developed to query participants about their standard practices for managing atypical squamous cells and atypical glandular cells on Pap tests; use of human papillomavirus testing; and use of vaginal estrogen cream in postmenopausal women before follow-up. RESULTS: There were 217 completed surveys (47.0% response rate). Responses of 194 qualified surveys are presented here. For women with first-time ASCUS (unqualified) and no previous history of cervical intraepithelial neoplasia (CIN), 16.4% of respondents would perform colposcopy. For ASCUS (favor squamous intraepithelial lesion [SIL]), a significantly higher percent, 74.9%, would proceed immediately to colposcopy (p < .001). For ASCUS (unqualified or favor SIL) in a woman with a previous history of CIN, 82.7% and 95.5% would perform colposcopy, respectively (p < .001). For a patient with AGUS, 97.5% would perform colposcopy (with or without endocervical curettage or endometrial biopsy). Human papillomavirus testing was seldom used in the management of ASCUS (10.4%) and AGUS (7.8%). CONCLUSIONS: Participants at the 2000 ASCCP Biennial Meeting made clear distinctions between ASCUS and AGUS in managing women with abnormalities on Pap, and management was consistent with guidelines published by the ASCCP, American College of Obstetricians and Gynecologists, and the National Cancer Institute.

Journal Article↗
PubMed2001

3D structure and significance of the GPhiXXG helix packing motif in tetramers of the E1beta subunit of pyruvate dehydrogenase from the archeon Pyrobaculum aerophilum.

As part of a structural genomics project, we have determined the 2.0 A structure of the E1beta subunit of pyruvate dehydrogenase from Pyrobaculum aerophilum (PA), a thermophilic archaeon. The overall fold of E1beta from PA is closely similar to the previously determined E1beta structures from humans (HU) and P. putida (PP). However, unlike the HU and PP structures, the PA structure was determined in the absence of its partner subunit, E1alpha. Significant structural rearrangements occur in E1beta when its E1alpha partner is absent, including rearrangement of several secondary structure elements such as helix C. Helix C is buried by E1alpha in the HU and PP structures, but makes crystal contacts in the PA structure that lead to an apparent beta(4) tetramer. Static light scattering and sedimentation velocity data are consistent with the formation of PA E1beta tetramers in solution. The interaction of helix C with its symmetry-related counterpart stabilizes the tetrameric interface, where two glycine residues on the same face of one helix create a packing surface for the other helix. This GPhiXXG helix-helix interaction motif has previously been found in interacting transmembrane helices, and is found here at the E1alpha-E1beta interface for both the HU and PP alpha(2)beta(2) tetramers. As a case study in structural genomics, this work illustrates that comparative analysis of protein structures can identify the structural significance of a sequence motif.

Amino Acid Sequence↗