Search PubMed⌕ Search

Biomedical subjects

J G Reid

Publications and source records attributed to J G Reid.

At least 19 recordsLinked to original sources
PubMed2005

Omega- and Omega+ production in central Pb + Pb collisions at 40 and 158A GeV.

Results are presented on Omega production in central Pb+Pb collisions at 40 and 158A GeV beam energy. For the first time in heavy ion reactions, rapidity distributions and total yields were measured for the sum Omega(-) + Omega(+) at 40A GeV and for Omega(-) and Omega(+) separately at 158A GeV. The yields are strongly underpredicted by the string-hadronic UrQMD model but agree better with predictions from hadron gas models.

Journal Article↗
PubMed2005

System-size dependence of strangeness production in nucleus-nucleus collisions at squareroot[sNN]=17.3 GeV.

Emission of pi+/-, K+/-, phi, and Lambda was measured in near-central C+C and Si+Si collisions at 158 AGeV beam energy. Together with earlier data for p+p, S+S, and Pb+Pb, the system-size dependence of relative strangeness production in nucleus-nucleus collisions is obtained. Its fast rise and the saturation observed at about 60 participating nucleons can be understood as the onset of the formation of coherent systems of increasing size.

Journal Article↗
PubMed2004

Lambda and lambda production in central Pb-Pb collisions at 40, 80, and 158A GeV.

Production of Lambda and Antilambda hyperons was measured in central Pb-Pb collisions at 40, 80, and 158A GeV beam energy on a fixed target. Transverse mass spectra and rapidity distributions are given for all three energies. The Lambda/pi ratio at midrapidity and in full phase space shows a pronounced maximum between the highest BNL Alternating Gradient Synchrotron and 40A GeV CERN Super Proton Synchrotron energies, whereas the Lambda/pi ratio exhibits a monotonic increase.

Journal Article↗
PubMed2004

Evidence for an exotic S= -2, Q= -2 baryon resonance in proton-proton collisions at the CERN SPS.

Results of resonance searches in the Xi(-)pi(-), Xi(-)pi(+), Xi;(+)pi(-), and Xi;(+)pi(+) invariant mass spectra in proton-proton collisions at sqrt[s]=17.2 GeV are presented. Evidence is shown for the existence of a narrow Xi(-)pi(-) baryon resonance with mass of 1.862+/-0.002 GeV/c(2) and width below the detector resolution of about 0.018 GeV/c(2). The significance is estimated to be above 4.2sigma. This state is a candidate for the hypothetical exotic Xi(--)(3/2) baryon with S=-2, I=3 / 2, and a quark content of (dsdsū). At the same mass, a peak is observed in the Xi(-)pi(+) spectrum which is a candidate for the Xi(0)(3/2) member of this isospin quartet with a quark content of (dsus[-]d). The corresponding antibaryon spectra also show enhancements at the same invariant mass.

Journal Article↗
PubMed2004

An investigation into the association among preterm birth, cytokine gene polymorphisms and periodontal disease.

OBJECTIVE: To investigate a putative relationship between preterm delivery and the carriage of polymorphic genes that code for the cytokines interleukin-1beta (IL-1beta) at codon +3953 and tumour necrosis factor-alpha (TNF-alpha) at codon -308 in a group of postpartum women and to elucidate if the concurrent presence of periodontal disease increased the risk of preterm delivery in this group. DESIGN: Case-control study SETTING: Postnatal wards at Guy's and St Thomas' Hospital Trust. POPULATION: Postpartum women from southeast London, UK. METHODS: Case subjects were defined as those who experienced a birth at less than 37 weeks of gestation. Control subjects gave birth at term. Demographic data were collected and a periodontal examination was performed. Blood samples were collected and analysed by restriction fragment length polymerase techniques for the presence of each of the allelic variants. MAIN OUTCOME MEASURES: The level of periodontal disease and the carriage of allelic variants of IL-1beta+3953 and TNF-alpha-308 genes. RESULTS: Forty-eight case subjects and 82 control subjects were assessed. There was no statistically significant difference in the carriage of the IL-1beta+3953 allelic variant between cases and controls (29%versus 18%, P= 0.112). However, 23 (48%) of the case subjects and 24 (29%) of controls were heterozygous or homozygous for the variant TNF-alpha-308 gene (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.0-5.0, P= 0.026). There was no association between the carriage of either the polymorphic IL-1beta+3953 or TNF-alpha-308 variant and the severity of periodontal disease. The combination of periodontal disease and the allelic variant did not increase the risk of preterm delivery. CONCLUSIONS: In this study, a higher proportion of women who delivered preterm carried the polymorphic TNF-alpha-308 gene. There did not appear to be any interaction between either of the genotypes and periodontal disease with preterm delivery as has been reported for bacterial vaginosis and the TNF-alpha-308 polymorphic gene.

Adult↗
PubMed2001

Event-by-event fluctuations of the Kaon-to-Pion ratio in central Pb+Pb collisions at 158 GeV per nucleon.

We present the first measurement of fluctuations from event to event in the production of strange particles in collisions of heavy nuclei. The ratio of charged kaons to charged pions is determined for individual central Pb+Pb collisions. After accounting for the fluctuations due to detector resolution and finite number statistics we derive an upper limit on genuine nonstatistical fluctuations, which could be related to a first- or second-order QCD phase transition. Such fluctuations are shown to be very small.

Journal Article↗
PubMed2001

The carriage of pro-inflammatory cytokine gene polymorphisms in recurrent pregnancy loss.

PROBLEM: Recurrent pregnancy loss (RPL) affects 2-4% of couples, and remains largely unexplained. Recent studies have examined the role of cytokines in the maintenance of normal pregnancy, which is linked with an increased expression of Th2 cytokines. Overexpression of Th1 cytokines is associated with RPL. Knowing that functional polymorphisms exist for certain cytokines, it has therefore been suggested that women with RPL may have a genetic predisposition to overexpress Th1 cytokines. METHOD OF STUDY: The genes for interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) carry functional gene polymorphisms. In both cases these are biallelic polymorphisms that can be detected by polymerase chain reaction followed by restriction fragment length polymorphism. The aim of this pilot study was to assess whether carriage of the rarer alleles (TNF*2 and IL-1B*2) could act as independent risk factors in recurrent miscarriage. RESULTS: We found an increased incidence in the carriage of TNF*2, more pronounced in those women with two or more miscarriages. Carriage of the IL-1B*2 either alone or in association with TNF*2 was not associated with recurrent miscarriage. CONCLUSION: There may be a role for these cytokine gene polymorphisms in RPL.

Abortion, Habitual↗
PubMed1997

Laxity of knee cruciate ligaments during pregnancy.

Pregnancy-related increase in ligament laxity may cause joint instability. The purpose of this study was two-fold: 1) to assess knee laxity changes during pregnancy and 2) to evaluate the effect of exercise on knee laxity due to a typical prenatal fitness program. The subjects were healthy pregnant women. One group (N = 27) participated in exercise classes designed according to national guidelines. The second group (N = 38) was more sedentary. A clinical arthrometer, KT-1000, was used, and anterior and posterior drawer tests were performed. The results were added and averaged for the two knees. Laxity was constant in the second half of pregnancy and had significantly decreased by 14% 4 months after birth. No influence of parity or exercise was detected. The exercise program employing minimal to moderate weight bearing did not result in any measurable increases in knee laxity and, therefore, appears to be appropriate with regard to knee stability. These results should not, however, be extended to different types of exercise programs without additional research.

Adult↗
PubMed1997

Desktop teleradiology in support of rural orthopedic trauma care.

UNLABELLED: Research has shown that diagnostic quality images for most teleradiology applications requires a sophisticated telemedicine system and access to a large amount of bandwidth. While the ideal standards have been set by those involved in evaluating teleradiology, these standards are impractical for many small rural health centers which deliver routine trauma care. While there is no disagreement about the ultimate need for this level of teleradiology support, the purpose of this research was to determine whether Orthopedists would be able to read plain radiographs of orthopedic trauma injuries using a desktop teleradiology system in support of rural trauma care. METHOD: Two radiology residents and two orthopedic residents viewed forty radiographs, twenty through a desktop teleradiology system and twenty in person. Diagnostic findings and certainty of diagnosis were recorded. FINDINGS: There was no statistically significant difference between modalities in orthopedic residents' ability to correctly diagnose orthopedic trauma injuries. Further, for those instances when the diagnosis was imprecise, the residents were aware of their inability to make an accurate diagnosis. CONCLUSION: Although the study was relatively limited and further research needs to be done, the use of desktop teleradiology in support of rural orthopedic trauma consultation is a promising alternative to the more expensive forms of telemedicine technology.

Evaluation Studies as Topic↗
PubMed1996

Trunk muscle parameters determined from MRI for lean to obese males.

Transverse magnetic resonance images at the L(4)-L(5) level of 26 males ranging in body mass index from 19.7 to 39.5 were digitized using a computer video monitor with mouse-mediated digitization software. The digitized musculature included the right and left psoas, rectus, abdominis, quadratus lumborum, oblique, and paraspinal muscle groups. From the digitized profiles, cross-sectional areas, and anteroposterior and mediolateral moments from the vertebral centroid were subsequently calculated. Multiple regression formulae were derived to predict the muscle parameters from the most strongly related anthropometrics. Cross-sectional area and moment arms for lean and obese groups were also compared. Significant regression formulae were derived for the cross-sectional area of the rectus abdominis and obliques, for mediolateral moment arms of the paraspinals, psoas, and obliques, and for anteroposterior moments of all four muscles. Comparison of muscle parameters for lean and obese subjects revealed minimal differences, though normalization of muscle cross-sectional areas by trunk area produced values which were statistically smaller for all muscles of the obese relative to lean subjects. RELEVANCE:--Identifying variations in trunk muscular geometry across specific population groups will assist in further refining the existing morphometric data base used to estimate the forces experienced about the lower back. By identifying these variations, it may be possible to observe factors which may predispose a specific population to low back pain.

Journal Article↗
PubMed1995

Exercise, posture, and back pain during pregnancy.

One of the expected benefits of exercise programmes for pregnant women is to reduce or prevent back pain by improving posture. The aim of this project was to evaluate the effect of fitness classes for pregnant women on posture and back pain. In this article, postural aspects are reported. Sixty five pregnant volunteers were included in the study, of whom 27 were enrolled in exercise classes designed according to Canadian guidelines and 38 acted as sedentary controls. Posture was assessed every 4 weeks during pregnancy and 4 months postpartum by measuring curvatures of the lumbar and thoracic spines in a standard relaxed standing position from lateral photographs. Laxity of knee ligaments was also monitored using a clinical arthrometer. Weight gain could explain part of lordosis increase during pregnancy but the effect was not very strong. No effect of exercise on posture was detected. RELEVANCE: This study showed that fitness classes for pregnant women designed according to Canadian guidelines had no detectable effect on posture during pregnancy.

Journal Article↗
PubMed1995

Exercise, posture, and back pain during pregnancy.

In this article the effect of exercise on pregnancy-related back pain is reported. Sixty five pregnant volunteers were included in the study, of whom 27 were enrolled in exercise classes designed according to Canadian guidelines, and 38 acted as sedentary controls. Back pain and functional limitations were assessed every 4 weeks during pregnancy and 4 months postpartum by questionnaires. No significant differences in back pain or functional limitations reported by the two groups were found. The biomechanical factors measured in this study, weight, back posture, and laxity, were unable to explain most of the variation in pain reported. RELEVANCE: This study showed that fitness classes for pregnant women designed according to Canadian guidelines had no detectable effect on back pain during pregnancy. If prevention of pregnancy-related back pain is sought through exercise, design of fitness programmes for pregnant women should be reconsidered.

Journal Article↗
PubMed1994

The geometry of the psoas muscle as determined by magnetic resonance imaging.

Magnetic resonance images from fifteen physically active and asymptomatic male volunteers were collected to present morphometric parameters on the psoas and its moment arms, which are important in the study of spinal mechanics and models for the investigation of low back pain. The mean age of the subjects was 21.5 +/- 1.8 years. Data were obtained from nine vertebral and/or intervertebral levels (L2, L2/L3, L3, L3/L4, L4, L4/L5, L5, L5/S1, S1). In general, the psoas increased in size as it descended the trunk, moving anteriorly and slightly laterally in relation to the vertebral column. Maximum cross-sectional areas for the psoas (M = 16.3cm2) were observed at the L4/L5 level. Right-left symmetry was apparent in the aforementioned dimension, but not with respect to the mediolateral (X) diameter of the muscle. The length of the X moment arm was significantly (p < .05) greater for the right versus the left psoas from L3 to S1, with the length increasing as the psoas descended the trunk. However, this trend was not noted for the anteroposterior (Y) moment arm where observed values remained relatively small throughout the course of the muscle. These results will contribute to the study of low back pain onset and the design of appropriate rehabilitation interventions by providing accurate morphometric parameters for biomechanical models to predict of the loading conditions of the spine in vivo.

Adolescent↗
PubMed1994

The study of human body segment parameters in biomechanics. An historical review and current status report.

The history of the techniques used to assess body segment parameters for biomechanical analysis has been reviewed. Three time periods of research were defined, based on the predominant instrumentation used, leading up to the modern era of computed tomography and magnetic resonance imagery. Organised in this manner, the significant techniques and findings were discussed. Current databases are deficient in several aspects: the small number of study participants used for development of standards, the potential inaccuracy of cadaver data compared with that of living humans, and the relative lack of study of diverse populations. Future efforts should be directed towards addressing these weaknesses in body segment parameter information, in order to improve biomechanical investigation in the clinica, ergonomic and sport environments.

Biomechanical Phenomena↗
PubMed1994

Detection of HCV-RNA in the blood donor population of Yorkshire.

The purpose of this study was to develop a reliable and specific polymerase chain reaction (PCR) for the detection of hepatitis C virus-ribonucleic acid (HCV-RNA) in the plasma of blood donors who attend the Yorkshire Regional Transfusion Centre. These donors had previously had a positive or indeterminate recombinant immunoblot assay (RIBA) result. For increased sensitivity of reaction and greater specificity of product, a 'nested-primer' PCR was used. One hundred and ninety-two samples were examined, of which 18 were RIBA-positive and HCV-RNA was detected in 15 (83%) of them. Of the 174 RIBA indeterminates only one (0.6%) had detectable HCV-RNA. The rate of HCV-RNA detection in fresh and archive samples was compared and found to be greater with the fresh samples.

Adult↗
PubMed1992

Comparison of three noninvasive methods for measuring scoliosis.

The premise behind most noninvasive techniques for the measurement of scoliotic conditions of the spine is that the lateral distortion of the spine relates directly to transverse rib cage deformity within the transverse plane. The focus of this study was to examine this assumption by comparing different noninvasive methods for the assessment of scoliotic curves. The three techniques examined were (1) use of the Scoliometer (SCOL), (2) use of the back-contour device (BCD), and (3) use of moiré topographic imaging (MTI). Fourteen subjects (10 female, 4 male) with idiopathic adolescent scoliosis were measured. Posterior-anterior radiographs were obtained for the clinical assessment of all subjects and were subsequently used to determine Cobb angles. Significant correlations between axial trunk rotation and Cobb-angle measurements were observed in the thoracic region (MTI, r = .80, df = 10, P less than .005; BCD, r = .70, df = 10, P less than .025; SCOL, r = .59, df = 10, P less than .025) but were not found within the lumbar region (MTI, r = .42; BCD, r = .17; SCOL, r = .20). Factors other than trunk deformity, such as the posture assumed by the subject during measurement, may have influenced axial trunk rotation. Hence, the techniques appear to provide valid estimations of lateral curvature of the spine in the thoracic region of the trunk but not the lumbar region. The results suggest that the measurement techniques cannot be used interchangeably in clinical recording.

Adolescent↗
PubMed1991

Morphometry of the human thigh muscles. A comparison between anatomical sections and computer tomographic and magnetic resonance images.

The present study examined the relative accuracy and precision of MR and CT procedures for determining the CSA of individual muscles from the human thigh. Serial AN, CT and MR cross-sections were obtained from three cadaveric lower limbs. The MR measurements provided accurate and precise values for the CSAs of most thigh muscles, generally within +/- 7.5% of the AN standard. In contrast, CT tended systematically to overestimate the AN CSA by 10-20%. Retest procedures indicated that highly reliable measurements could be obtained from both MR and CT images. However, subjective interpretations of boundaries between closely apposed muscle bellies, particularly for muscles with more than one head, were necessary for resolving entities in the imaging records and this decreased the relative accuracy of MR and CT measures. Interestingly, MR records demonstrated an incomplete septum between vastus lateralis and vastus intermedius more prominently than AN cross-sections. The novel cross-validation procedures used in this study also highlighted several system-based errors in the MR records that, if undetected and left uncorrected, would have seriously biased the morphometric data obtained with this technique. In general, MR provides high resolution images of the human thigh muscles which may be used to obtain valid measures of the CSA of these structures.

Cadaver↗