PubMed Health⌕ Search

Biomedical subjects

S Jarvis

Publications and source records attributed to S Jarvis.

At least 19 recordsLinked to original sources
PubMed2005

How might districts identify local barriers to participation for children with cerebral palsy?

OBJECTIVES: To explore how data about participation and the local environment might be used to identify barriers to participation for children with cerebral palsy. METHODS: Participation is measured at 5 years of age using the six domains of the lifestyle assessment questionnaire. Individual child score profiles are compared with expected patterns from similar children and with the use of relevant services. Average scores for districts are compared with selected local authority performance indicators. Self-completion questionnaires are used to solicit information on barriers from families of children. RESULTS: Individual children who have poorer-than-expected participation scores and those who make less-than-expected use of relevant services can be identified. Children who live in districts with more facilities for the disabled appear to have better social participation scores. Common local barriers as well as specific access problems for individuals are revealed by simple questionnaires to families. Attitudes of strangers and staff in public places, lack of suitable transport and the presence of stairs are important barriers in many settings. CONCLUSIONS: Environmental barriers for children with cerebral palsy can be identified and related to their participation.

Activities of Daily Living↗
PubMed2005

Intrauterine growth restriction and fetal body composition.

OBJECTIVE: To assess the differences in fetal body compartments between fetuses with normal growth and those with reduced intrauterine growth, during the third trimester, through ultrasonographic determination of subcutaneous tissue thickness (SCTT). METHODS: Twenty-eight patients were enrolled into this case control study carried out at 30-31 weeks' gestation. Two study groups were matched for maternal age and pregestational body mass index: controls (n = 14) and intrauterine growth-restricted (IUGR) fetuses (n = 14). Routine ultrasound-derived biometric parameters (head circumference, abdominal circumference, femur length and humerus length) were measured. Additionally, the mid-arm fat mass and lean mass (MAFM and MALM), the mid-thigh fat mass and lean mass (MTFM and MTLM), the abdominal fat mass (AFM) and the subscapular fat mass (SSFM) were measured. The Mann-Whitney U-test and Student's t-test were used to compare the two groups. RESULTS: The abdominal circumference and the humerus were significantly smaller in IUGR fetuses than in controls. Most of the SCTT values were different in the two groups. The SSFM (3.6 +/- 1.1 vs. 2.6 +/- 0.7 mm; P = 0.011), the AFM (5.1 +/- 0.7 vs. 4 +/- 1 mm; P = 0.01), the MAFM (3.5 +/- 0.9 vs. 2.2 +/- 0.8 cm2; P < 0.01) and MALM (2.1 +/- 0.4 vs. 1.7 +/- 0.5 cm2; P = 0.029) were all significantly greater in fetuses with normal development compared to those with growth restriction. CONCLUSIONS: During the third trimester, SCTT (with the exception of MTFM and MTLM) is reduced in fetuses with IUGR. Furthermore, MALM is lower in growth-restricted fetuses, confirming that the parameters measured in this study are affected in IUGR fetuses. Our findings indicate that specific changes in fetal body compartments occur as a result of chronic metabolic impairment.

Abdomen↗
PubMed2005

Case gender and severity in cerebral palsy varies with intrauterine growth.

BACKGROUND: There is an unexplained excess of cerebral palsy among male babies. There is also variation in the proportion of more severe cases by birth weight. It has recently been shown that the rate of cerebral palsy increases as intrauterine size deviates up or down from an optimum about one standard deviation heavier than population mean weight-for-gestation. AIMS: To determine whether the gender ratio or the severity of cases also varies with intrauterine size. METHODS: A total of 3454 cases of cerebral palsy among single births between 1976 and 1990 with sufficient data to assign case severity (based on intellectual impairment and walking ability) and to compare weight-for-gestation at birth to sex specific fetal growth standards, were aggregated from nine separate registers in five European countries. RESULTS: The greater the degree to which growth deviates either up or down from optimal weight-for-gestation at birth, the higher is the rate of cerebral palsy, the larger is the proportion of male cases, and the more severe is the functional disability. Compared to those with optimum growth the risk of more severe cerebral palsy in male babies is 16 times higher for those with a birth weight below the 3rd centile and four times higher when birth weight is above the 97th centile. In contrast, for mild cerebral palsy in female babies the excess risks at these growth extremes are about half these magnitudes. CONCLUSIONS: Among singleton children with cerebral palsy, abnormal intrauterine size, either small or large, is associated with more severe disability and male sex.

Birth Weight↗
PubMed2003

A new method for characterizing carotid plaque: multiple cross-sectional view echomorphology.

PURPOSE: This study compares the ability of computer-derived B-mode ultrasound gray-scale measurements from a single longitudinal view (SLV) versus multiple cross-sectional views (MCSV) to differentiate symptomatic from asymptomatic carotid plaque causing more than 70% stenosis. METHOD: Seventy-four internal carotid artery (ICA) stenoses (70%-99%; 33 asymptomatic, 41 symptomatic within 3 months) were imaged to obtain the "best" SLV and five to eight MCSV images at 5 mm intervals from the carotid bifurcation. Digitized sonograms were computerized and normalized to the gray scale median (GSM) of blood (0) and vessel adventitia (200). Plaque GSM was determined for each frame (image analysis, MATLAB 5.3). General risk factors for stroke and plaque echogenicity (SLV GSM; minimum MCSV GSM; cross-sectional axial heterogeneity (highest minus lowest MCSV GSM) were determined for each group. RESULTS: Risk factors for stroke were similar in both groups, as was mean SLV GSM: symptomatic, 34 (95% confidence interval [CI], 24.8-43.0), asymptomatic, 43 (CI, 32.6-53.2); P =.1. Minimum MCSV GSM was lower for symptomatic plaque: 7 (CI, 4.2-9.8] vs 18.3 (CI, 12.2-24.5); P =.002. Greater axial GSM heterogeneity was present in symptomatic plaque: 34.5 (CI, 27.2-41.9) vs 16 (CI, 11.0-20.8); P =.0001. CONCLUSIONS: MCSV cross-sectional imaging that enables objective assessment of regional plaque echolucency and heterogeneity is more sensitive than SLV sonography for differentiating symptomatic from asymptomatic plaque.

Aged↗
PubMed2003

Snoring, not just a social nuisance.

Snoring is a very common source of complaints from partners and neighbours. Snorers themselves are less likely to be affected, unless they have associated daytime sleepiness caused by the sleep disruption from obstructive sleep apnoea. There is increasingly firm evidence that obstructive sleep apnoea is associated with hypertension, cardiovascular, cerebrovascular and metabolic problems such as insulin resistance, even at mild levels which may not cause much daytime somnolence. In addition, the central and obstructive apnoeas found in cardiac failure affect heart muscle function. Treatment of the apnoea improves blood pressure and cardiac function and is likely to have a beneficial effect on mortality. Since obstructive sleep apnoea is common it should be sought by appropriate questioning in these patient groups. The treatments for obstructive sleep apnoea are effective but cumbersome and this remains a challenge if patients do not achieve obvious early benefits such as reduction in sleepiness or breathlessness.

Adult↗
PubMed2001

The effect of parity and environmental restriction on behavioural and physiological responses of pre-parturient pigs.

There is increasing evidence that restriction of pre-parturient behaviour in pigs is stress-inducing, characterised by an elevation in hypothalamic-pituitary-adrenal (HPA) activity in gilts. To determine whether pigs adapt to behavioural restriction, through modification of nest-building behaviour, we studied pre-parturient pigs in either farrowing crates (no bedding, n=7) or straw-bedded pens (n=7) in their first (gilts) and second (sows) parity, with physiological measurements being taken in the second parity. Observations and blood sampling were carried out during the pre-parturient phase. Crated pigs changed posture more often than penned pigs (F(1,12)=7.06, P<0.05), with the number of posture changes reducing across parities in both environments. The reduction in posture changing was more apparent in the crated sows which may indicate that attempted nest-building behaviour of sows with prior experience of farrowing crates is less fragmented. The crated pigs spent a greater proportion of time sitting across both parities (F(1,12)=9.4, P<0.01), and spent less time manipulating available substrates (F(1,12)=10.67, P<0.05). There was a tendency for penned pigs to spend a greater proportion of time standing (F(1,12)=3.77, P=0.076) with peak nesting behaviour occurring earlier in relation to parturition than in crated pigs. In addition penned sows performed more floor-directed behaviour than penned gilts, and at an earlier stage in relation to parturition. However, crated sows also performed peak nest-building earlier than crated gilts. Plasma cortisol profiles indicated elevated HPA activity in crated sows during the pre-parturient period (F(42,303)=1.43, P<0.05) suggesting increased physiological stress, however, the difference between crated and penned sows was less than that previously seen in gilts. The increased range of pre-parturient behaviours seen in the penned sows suggests that experience may result in an 'improvement' in their nest-building behaviour: earlier preparation of the nest site and then subsequent manipulation of substrates. The crated sows appeared to show some behavioural adaptation to the crate environment; earlier peak in floor directed behaviour and total substrate directed behaviour, reduced posture changing. In conclusion the nest-building behaviour of pigs is modified over parities with adaptation to the behavioural restrictions imposed by the farrowing crate. However, this adaptation, through prior experience, does not completely reduce the elevation in HPA activity previously reported in pre-parturient crated gilts.

Journal Article↗
PubMed2000

The effect of opioid antagonism and environmental restriction on plasma oxytocin and vasopressin concentrations in parturient gilts.

Oxytocin plays an important role at parturition due to its involvement in uterine contractions, foetal expulsion and the onset of maternal behaviour. The role of the related neurohypophysial hormone, vasopressin, is less clear; however, there is some evidence that it is also involved in maternal behaviour and its role in osmotic regulation is well established. The aim of this study was to investigate the inhibitory effects of endogenous opioids on these hormones during the expulsive phase of parturition in the pig, and to examine how opioid restraint interacts with environmental restriction. The subjects of this study were 31 Large Whitex Landrace primiparous sows (gilts). An indwelling jugular catheter was implanted under general anaesthesia at 12 days before the expected parturition day (EPD). From 5 days before the EPD 15 of the gilts were individually housed in a restrictive parturition crate without straw and 16 were individually housed in a straw-bedded pen. Blood samples were taken with increasing frequency towards and during parturition through a catheter extension to reduce disturbance. At 7.5 min after the birth of the first piglet half of the gilts in each environment received a dose of the opioid receptor antagonist naloxone (1 mg/kg, i.v.) with the remaining gilts receiving saline as a control. Overall, there was no effect of environment on either circulating oxytocin or vasopressin. However, both oxytocin and vasopressin were inhibited by endogenous opioids during the expulsive phase. The inhibitory effects of opioids on these hormones did not appear to have any adverse effects on the progress of parturition as judged by cumulative piglet birth intervals. The regulation of the opioid inhibition of oxytocin and vasopressin during parturition is discussed in relation to other neurotransmitters and whether opioid inhibition of these neurohypophysial hormones is part of the 'normal' physiological response to parturition or whether it is stress-induced.

Analysis of Variance↗
PubMed1999

High throughput liquid chromatography/mass spectrometric analyses using a novel multiplexed electrospray interface.

A novel four- channel multiplexed electrospray liquid chromatography interface is described. This device has been used to analyse both single components and mixtures by liquid chromatography/mass spectrometry (LC/MS) as well as synthetic samples prepared by automated procedures. These data provided unambiguous molecular weight assignments to both major components and synthetic by-products in these samples. In this work particular attention has also been paid to the elimination of interchannel crosstalk. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed1999

The distribution of nerve fibres immunoreactive for vasoactive intestinal peptide, calcitonin gene-related peptide, substance P and dopamine beta-hydroxylase in the normal equine larynx.

The autonomic innervation of the mammalian respiratory system is complex, and involves a wide variety of peptide and non-peptide neurotransmitters which will have an important role in normal laryngeal function and the response to disease. This innervation has been partially described in the horse airway and lung, but there is no information on the equine larynx. This paper describes the expression and distribution of nerve fibres immunoreactive for vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), substance P (SP) and the adrenergic enzymatic marker dopamine beta-hydroxylase (DBetaH) in the mucosa of the equine larynx. The overall relative density of nerve fibres immunoreactive for the different antigens was VIP>>CGRP>SP>>DBetaH. There were differences in the distribution of nerve fibre types, although each antigen was found in nerve fibres adjacent to blood vessels and mucous glands. VIP -like immunoreactivity (VIP -Li) was particularly extensive in association with mucous glands. SP - and CGRP -like immunoreactivity (SP -Li, CGRP -Li) were also seen close to the epithelium, with occasional nerve fibres coursing beneath and between the epithelial cells. Fragments of SP -Li and CGRP -Li fibres were also present in large nerve fibre bundles and ganglionic cell clusters, but not in the neurons themselves. The density of nerve fibres immunoreactive for DBetaH was very low and restricted to blood vessels and mucous glands. There was marked variation in the density of nerve fibres at the different sites, with the greatest density, particularly for VIP, over the arytenoid cartilage. Immunoreactive nerve fibres were less plentiful over the epiglottis, and the density of all types of nerve fibres was low over the cricoid cartilage. Overall VIP -Li nerve fibres were the most plentiful.

Animals↗
PubMed1998

Mutations in the pore regions of the yeast K+ channel YKC1 affect gating by extracellular K+.

The product of the Saccharomyces cerevisiae K+-channel gene YKC1 includes two pore-loop sequences that are thought to form the hydrophilic lining of the pore. Gating of the channel is promoted by membrane depolarization and is regulated by extracellular K+ concentration ([K+]o) both in the yeast and when expressed in Xenopus oocytes. Analysis of the wild-type current now shows that: (i) [K+]o suppresses a very slowly relaxing component, accelerating activation; (ii) [K+]o slows deactivation in a dose-dependent fashion; and (iii) Rb+, Cs+ and, to a lesser extent, Na+ substitute for K+ in its action on gating. We have identified single residues, L293 and A428, at equivalent positions within the two pore loops that affect the [K+]o sensitivity. Substitution of these residues gave channels with reduced sensitivity to [K+]o in macroscopic current kinetics and voltage dependence, but had only minor effects on selectivity among alkali cations in gating and on single-channel conductance. In some mutants, activation was slowed sufficiently to confer a sigmoidicity to current rise at low [K+]o. The results indicate that these residues are involved in [K+]o sensing. Their situation close to the permeation pathway points to an interaction between gating and permeation.

Cations, Monovalent↗
PubMed1998

Effect of community based management in failure to thrive: randomised controlled trial.

OBJECTIVE: To evaluate the effectiveness of a health visitor led intervention for failure to thrive in children under 2 years old. DESIGN: Controlled trial, randomised by primary care practice. SETTING: Newcastle upon Tyne health district. INTERVENTION: Structured health visitor management, with dietetic, paediatric, and social work input as required. SUBJECTS: 229 children (120 in intervention practices and 109 in control practices) were identified as failing to thrive by population screening during the first 2 years of life. Follow up was by home visit of a research nurse and review of the childrens' records at age 3 years. MAIN OUTCOME MEASURES: Follow up weight and height and number of routinely collected weights. RESULTS: 95 of the 97 families offered intervention completed at least the initial assessment. At follow up, 187 (82%) records were reviewed, and these suggested that 15 (16%) controls were lost to follow up immediately after the screening weight was taken compared with only one child in the intervention group. In the 134 (58%) families who consented to home visits, children in the intervention group were significantly heavier and taller and were reported to have better appetites than childen in the control group, although both groups were equally satisfied by the services they had received. When the children were last weighed, 91 (76%) in the intervention group had recovered from their failure to thrive compared with 60 (55%) in the control group (P<0.001). CONCLUSION: In failure to thrive, health visitor intervention, with limited specialist support, can significantly improve growth compared with conventional management.

Body Height↗
PubMed1998

The effect of environment on plasma cortisol and beta-endorphin in the parturient pig and the involvement of endogenous opioids.

Previous work has indicated that plasma cortisol increases during farrowing in the pig suggesting increasing physiological stress. The aim of this study was to determine changes in plasma cortisol and beta-endorphin over farrowing in the pig to obtain a more detailed profile of pituitary and adrenal release at this time and also to investigate the involvement of endogenous opioids in the mediation of the HPA axis. Indwelling jugular catheters were implanted, under general anaesthesia, in 31 Large White x Landrace gilts approximately 15 days before the expected parturition day (EPD). Gilts were moved into either a farrowing crate, without straw (n = 15), or a straw-bedded pen (n = 16) 5 days before the EPD. Samples were taken during the pre-farrowing period and then during farrowing itself. At 7.5 min after the birth of the first piglet (BFP), gilts either received naloxone, an opioid antagonist, (1 mg kg(-1) body weight, i.v.) or a control dose of saline. Plasma beta-endorphin increased following the BFP but remained fairly constant over the third and fourth hour of farrowing. Plasma cortisol continued to increase over the 4 h following the BFP. Changes seen in these hormones were generally insensitive to the environment and there was little evidence of opioid mediation of the HPA axis at parturition. From these results it is suggested that certain aspect(s) of parturition itself stimulate the HPA axis. However it is unknown if the rise in plasma cortisol is a result of some stress-inducing factor of the parturition process or whether it reflects a metabolic function. The study also demonstrates the lack of any inhibitory mediation of the HPA axis by endogenous opioids at parturition.

Animals↗
PubMed1998

Dissection of multi-protein complexes using mass spectrometry: subunit interactions in transthyretin and retinol-binding protein complexes.

Complexes formed between transthyretin and retinol-binding protein prevent loss of retinol from the body through glomerular filtration. The interactions between these proteins have been examined by electrospray ionization combined with time-of-flight mass analysis. Conditions were found whereby complexes of these proteins, containing from four to six protein molecules with up to two ligands, are preserved in the gas phase. Analysis of the mass spectra of these multimeric species gives the overall stoichiometry of the protein subunits and provides estimates for solution dissociation constants of 1.9 +/- 1.0 x 10(-7) M for the first and 3.5 +/- 1.0 x 10(-5) M for the second retinol-binding protein molecule bound to a transthyretin tetramer. Dissociation of these protein assemblies within the gas phase of the mass spectrometer shows that each retinol-binding protein molecule interacts with three transthyretin molecules. Mass spectral analysis illustrates not only a correlation with solution behavior and crystallographic data of a closely related protein complex but also exemplifies a general method for analysis of multi-protein assemblies.

Animals↗