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Biomedical subjects

D Roberts

Publications and source records attributed to D Roberts.

At least 37 records · Page 2Linked to original sources
PubMed1998

Longitudinal study of bone turnover after acute spinal cord injury.

Increased bone turnover is a sequel of spinal cord injury (SCI) and predisposes to a number of clinically relevant complications, including osteoporosis and fractures. There are limited data available regarding the changes in modern markers of bone metabolism after SCI. We report a 6-month longitudinal follow-up of biochemical markers of bone metabolism (free and total deoxypyridinoline, total pyridinoline, N-telopeptide, osteocalcin, and total alkaline phosphatase) and bone mineral densitometry in 30 subjects with acute SCI. Markers of bone formation showed only a minor rise, remaining within the reference range. In contrast, markers of bone resorption showed a significant rise after acute SCI, peaking around weeks 10-16, with values up to 10 times the upper limit of normal. Paired bone mineral densities (n = 11; on the average, determined 14 weeks apart) showed no change at the hip, lumbar spine, or radius, but demonstrated a decrement in the entire lower limbs. changes in biochemical markers of bone formation and resorption were comparable in patients with quadriplegia and paraplegia, except for a greater increase in quadriplegics in pyridinoline, expressed as a percentage of baseline. In conclusion, a marked increase in bone resorption and modest changes in bone formation occur after SCI, and possibly increased bone resorption occurs in quadriplegia.

Adolescent↗
PubMed1998

The fetal outcome in pregnancies with isolated reduced amniotic fluid volume in the third trimester.

Our aim was to assess the outcome of pregnancies where oligohydramnios, defined by a published gestational reference range for amniotic fluid index, was the only abnormal finding at third trimester scan, and all other ultrasound parameters including biometry were within normal limits at initial scan. A retrospective case-control study was performed at The Liverpool Maternity Hospital. 103 pregnancies with reduced amniotic fluid index in the third trimester and apparently normal fetal growth profile ultrasonographically were identified from ultrasound reports throughout 1993. Pregnancies in the third trimester with normal amniotic fluid index on index scan were also identified from these reports and 103 were matched for parity, gestational age at delivery, mode of onset of labour, presentation at labour and medical conditions. Exclusion criteria were ruptured membranes, fetal abnormalities, estimated fetal weight below the fifth centile at index scan and multiple pregnancies. The outcome criteria were birthweight, Apgar scores at delivery, induction and emergency delivery for fetal reasons and admission to Neonatal Intensive Care Unit. Statistical analysis was performed by Fisher's exact test and Gart's odds ratio. Compared with controls, pregnancies in the reduced liquor group had a higher number of babies below the 5th centile (odds ratio 5.2, 95% confidence interval 1.6 to 22), a higher risk of induction for fetal reasons (odds ratio 34.4, 95% confidence interval 5.35 to 1425.5) and admission to Neonatal Intensive Care Unit (odds ratio 9.77, 95% confidence interval 1.3 to 432). Any observed difference in the need for emergency delivery due to fetal reasons was not clinically significant (odds ratio 2.16, 95% confidence interval 0.77 to 6.6) The definition used for oligohydramnios used in this study appears to identify a group of babies with a fourfold risk of low birthweight and a high risk of admission to the Neonatal Intensive Care Unit and induction of labour for fetal reasons. This would suggest that pregnancies with isolated oligohydramnios require some form of fetal monitoring and further prospective studies are required to determine the most appropriate method.

Apgar Score↗
PubMed1998

Function after anterior cruciate ligament injuries. Influence of visual control and proprioception.

Information about limb positions and movements consists of input from visual, vestibular, cutaneous, muscular, tendinous and joint receptors, but the relative contribution from each type and location of receptors is not known. The aim of this study was: a) to measure the contribution from visual control on extremity function, as measured with a one-leg hop test in healthy persons, in patients with an asymptomatic ACL injury, after non-operative treatment and in patients with a stable knee after an ACL reconstruction, b) to investigate if there was any relation between proprioception from the extremity, as measured with the threshold for detecting passive motion of the knee, and the one-leg hop test with a gradual decrease in visual control. There was a decrease in hop-length when the subjects were deprived of visual control that was significant when the dominant eye or both eyes were blinded, both in the 2 patient groups and the reference population. The magnitude of the length reduction did not differ between the groups or between injured and healthy limbs. In all 4 threshold tests performed as a measure of peripheral proprioception, a stronger relation to hop-length was recorded for the blinded hop than with full visual control in the patients with nonoperated ACL injuries. The coefficients of correlation between hop-length and the proprioceptive recordings in the injured limb were of the same magnitude as on the healthy side.

Adult↗
PubMed1998

The effect of cardiopulmonary bypass on blood cell filterability in children undergoing cardiac surgery.

BACKGROUND: The extended use of cardiopulmonary bypass (CPB) in cardiac surgery is limited because of damage to blood which in adults has been assessed by alterations in blood cell rheology. Blood trauma assessment in children is difficult because of the restrictions in sample volume and frequency but needs to be established from time to time in order to study the tolerance to new surgical and extracorporeal techniques. MATERIALS AND METHODS: Fourteen pediatric patients undergoing cardiac surgery with CPB for congenital heart disease corrections were studied. Whole blood, red blood cell and white blood cell rheology (filterability) were monitored before, during and after CPB using the St. George filtrometer that used small amounts of blood. RESULTS: The results showed that all the rheologic parameters were altered during the blood trauma of CPB and were outside the reference values before, during and after CPB. CONCLUSIONS: This suggested that blood cell rheologic disturbances did not recover soon after CPB and this may be of interest in long term follow-up to understand responses and recovery patterns to disease and interventions associated with pediatric heart surgery using CPB.

Blood Cell Count↗
PubMed1998

Modification of the standard method used in the United Kingdom for counting Escherichia coli in live bivalve molluscs.

The standard method for counting Escherichia coli in live bivalve molluscs is labour intensive and takes three days to obtain a result. Modifications to the standard method were investigated in a collaborative trial conducted in five centres. No significant difference was found between results based on the presence of acid at 24 hours (h) in first stage tests and those based on the presence of acid and gas after 48 h (standard method). The use of the chromogenic medium BCIG (5-bromo-4-chloro-3-indolyl-beta-D glucuronide) agar incubated at 44 degrees C to confirm first stage tests was also found to give equivalent results to conventional confirmation tests. The preferred, modified method removes the presence of gas as a criterion of detection, uses a chromogenic agar medium to confirm the presence of E. coli, and gives results within 48 h. A distribution of simulated samples and selected strains of E. coli to other laboratories using the PHLS external quality assurance scheme for shellfish found no significant difference between results obtained by the standard and modified methods.

Animals↗
PubMed1998

Computerized dynamic visual acuity test in the assessment of vestibular deficits.

OBJECTIVE: The study was designed to measure dynamic visual acuity (DVA) during head movement as an assessment of the functional impact of vestibular deficits. STUDY DESIGN: The study design was a prospective, clinical study. SETTING: The study was performed in a tertiary, ambulatory referral center. PATIENTS: Forty-two normal subjects, 29 patients with unilateral vestibular loss, and 26 patients with bilateral vestibular hypofunction who were 19-87 years of age were examined. INTERVENTION: Diagnostic intervention was performed. MAIN OUTCOME MEASURE: Main outcome measures included the reliability, sensitivity, and specificity of a computerized test that measures visual acuity during head movement in normal subjects and in patients with vestibular deficits. RESULTS: The computerized DVA test was reliable in both normal subjects (intraclass correlation coefficient [ICC] r=0.87) and in patients with vestibular deficits (ICC r=0.83). The sensitivity of the DVA test was 94.5% and the specificity was 95.2%. The positive predictive value (individuals who test positive on the DVA test who will have a vestibular deficit) was 96.3%. The negative predictive value (individuals who test negative on the DVA test who will not have a vestibular deficit) was 93%. CONCLUSIONS: The computerized DVA test is reliable and is able to distinguish among normal subjects and patients with vestibular deficits.

Adult↗
PubMed1997

Intercellular adhesion molecule-1 and CD36 synergize to mediate adherence of Plasmodium falciparum-infected erythrocytes to cultured human microvascular endothelial cells.

We have compared the adhesion of Plasmodium falciparum-infected erythrocytes to human dermal microvascular endothelial cells (HDMEC) and human umbilical vein endothelial cells (HUVEC) and have assessed the relative roles of the receptors CD36 and intercellular adhesion molecule-1 (ICAM-1). HUVEC (a cell line that expresses high levels of ICAM-1 but no CD36) mediate low levels of adhesion, whereas HDMEC (which constitutively express CD36) mediate high levels of adhesion even before ICAM-1 induction ICAM-1 expression leads to yet greater levels of adhesion, which are inhibited both by anti-ICAM-1 and CD36 mAbs, despite no increase in the expression of CD36. The results indicate the presence of a substantial population of infected cells that require the presence of both receptors to establish adhesion. Synergy between these receptors could be demonstrated using a number of parasite lines, but it could not be predicted from the binding of these same parasite lines to purified ICAM-1 and CD36. This phenomenon could not be reproduced using either purified receptors presented on plastic, or formalin-fixed HDMEC, suggesting that receptor mobility is important. This is the first study to demonstrate receptor synergy in malaria cytoadherence to human endothelial cells, a phenomenon necessary for parasite survival and associated with disease severity.

Animals↗
PubMed1997

Skin cancer prevention.

The Health of the Nation objectives for skin cancer will only be achieved through prevention and early detection. The key Health of the Nation objective to halt the year on year increase in skin cancer by 2000 means that this ambitious target must be tackled through a multidisciplinary approach. In this article, the authors suggest that most future strategies for reducing skin cancer will be based in primary care and some of these will be led by nurses.

Health Priorities↗
PubMed1997

Identification of a zinc-finger gene at 6q25: a chromosomal region implicated in development of many solid tumors.

We have used a rat model of epithelial ovarian cancer to identify a gene that shows decreased or lost expression in independently transformed rat ovarian surface epithelial cell lines compared to the normal progenitor cells. Hence, we refer to this gene as Lot-1 (Lost on transformation 1, GenBank accession no. U72620). Here, we report the cloning of the likely human homologue and its initial characterization. The deduced amino acid sequences of the cDNAs for rat and human LOT-1 (GenBank accession no. U72621) contain seven zinc finger motifs of the C2H2 type as well as proline and glutamine rich areas. The genes share 76.4% identity at the nucleotide level, 67.7% at the amino acid level and 85.5% within the seven zinc finger motifs. LOT-1 is ubiquitously expressed in normal human tissues but was not expressed in four of 11 (36%) human ovarian cancer cell lines or spontaneously transformed human ovarian surface epithelial cells. The human gene maps to chromosome 6 at band q25. We show that there is a 38% incidence of allelic loss at this chromosomal location in human ovarian cancers. This chromosomal region has also been implicated in the genesis of breast, kidney, and pleural mesothelial cancers. We suggest that this newly identified gene is not only of intrinsic interest as a ubiquitously expressed probable transcription factor but is a plausible candidate for the tumor suppressor gene which likely resides in the region of chromosome 6 defined by band q25.

Amino Acid Sequence↗
PubMed1997

Synthesis and evaluation of 2-(arylamino)imidazoles as alpha 2-adrenergic agonists.

A series of 2-(arylamino)imidazoles was synthesized and evaluated for activity at alpha 1- and alpha 2-adrenoceptors. This class of agents has been shown to have potent and selective agonist activity at the alpha 2-adrenoceptors. The most potent member of this class, 2-[(5-methyl-1,4-benzodioxan-6yl)amino]imidazole, proved efficacious for the reduction of intraocular pressure upon topical administration and for the reduction of blood pressure upon intravenous administration. During the course of our studies, we developed a new reagent that allowed rapid assembly of the target compounds. This reagent, N-(2,2-diethoxyethyl)carbodiimide, was convenient to prepare and was stable under low-temperature storage conditions.

Adrenergic alpha-2 Receptor Agonists↗
PubMed1997

Proprioception after an acute knee ligament injury: a longitudinal study on 16 consecutive patients.

A defect in proprioception has been found in selected patient groups that have an anterior cruciate ligament deficient knee at different times after the original injury. The time of development and the extent of such defects were studied longitudinally on 16 consecutive patients. During the first year after a primary knee injury, which included a complete rupture of the anterior cruciate ligament, we repeatedly performed three tests of proprioception: (a) one to determine the threshold for detecting a passive motion from starting positions of 20 and 40 degrees, (b) an active reproduction of a passive angular change, and (c) a visual estimation of a passive angular change. The injured limb was compared with the uninjured limb and with the limbs of an age-matched reference group of healthy subjects. The population did not have a normal distribution, and some patients had consistently extreme recordings in the threshold tests at the various times of testing. Significant differences were found between the groups at the starting position of 20 degrees, when the injured knee was compared with the uninjured knee, after 1 month (p = 0.05), and after 2 months (p = 0.03). There was a trend toward a higher threshold for detecting a passive motion when the injured side was compared with the knees of the reference group at 1 month (p = 0.06) but not later on. A similar pattern was found for the injured knee at the starting position of 40 degrees, but it was not significant. An impaired ability to detect a passive motion was registered for the nearly extended knee 1 and 2 months after a primary injury. In the active reproduction and visual estimation tests, no significant defects were found at any time during the first year in these consecutively studied patients.

Adolescent↗
PubMed1997

Neonatal exposure to coumestrol, a phytoestrogen, does not alter spermatogenic potential in rats.

The objective of this study was to determine the effects of neonatal exposure to phytoestrogens on male reproductive function as adults. Male rats were injected either with 100 micrograms coumestrol or DMSO (controls) daily during their first 5 d of life. Pituitary gland, testes, sex accessory organs, and blood were collected on d 60 of life. Serum testosterone, LH, and FSH levels were determined by RIA. Levels of steady-state mRNA for gonadotrophin subunits (LH beta and FSH beta were determined by Northern blot analysis and quantified by a scanning densitometer. Coumestrol had no effect on weights of testes and sex accessory organs, or sperm count. Similarly, there were no significant differences among serum concentrations of testosterone, LH beta and FSH of coumestrol-treated rats and those of controls. Whereas steady state levels of LH beta mRNA in coumestrol-treated rats did not differ from those of controls, steady state levels of FSH beta mRNA increased (37%) in treated animals. However, the augmented FSH beta mRNA expression in coumestrol-treated rats did not negatively affect reproductive potential in male rats. We conclude that neonatal exposure to coumestrol does not alter reproductive organ structure or spermatogenic potential in male rats.

Animals↗
PubMed1997

Transesophageal echocardiographic detection of complications after Cabrol's procedure.

Cabrol's procedure represents an improvement on earlier surgical techniques used in the management of a patient with aortic insufficiency associated with an aneurysm of the ascending aorta. We report a patient in whom the diagnosis of complications after a Cabrol procedure was facilitated by transesophageal echocardiography. The role of transesophageal echocardiography in the follow-up of these patients is discussed.

Abscess↗
PubMed1997

Liaison mental health nursing: origins, definition and prospects.

Liaison mental health nursing is an evolving specialist area of mental health nursing in the United Kingdom (UK). It has many similarities with 'psychiatric consultation liaison nursing' practised in the United States of America (USA), but there have been differences in its development. It is well established in general health settings where psychological problems are most apparent, such as accident and emergency services and oncology. However, it lacks clear definition. The author addresses this by examining the literature for evidence of how the role has developed, and how it is currently described. The position of liaison mental health practice within nursing is discussed, and also its relationship to liaison psychiatry. The theoretical base of this specialty may be seen as an integration of biological, psychological and sociological perspectives. There is no current programme of training for liaison mental health nurses, and this is likely to inhibit its recognition as a specialty in the UK. As interest grows in psychosocial aspects of physical health, liaison mental health nursing has the potential to provide a focus for research within nursing. Areas for further development are reviewed, and a research agenda is proposed.

Consultants↗
PubMed1997

Enzyme exposure, smoking and lung function in employees in the detergent industry over 20 years. Medical Subcommittee of the UK Soap and Detergent Industry Association.

This study was undertaken to examine the long term relationship between lung function, smoking and exposure to enzymes in the detergent industry. A total of 731 male workers from five locations in the United Kingdom were subject to respiratory health surveillance including lung function testing over a period of 4-20 years. Exposure groups were defined by job history. Significantly different rates of fall in FEV1 and FVC with time were found by geographical location and by smoking habit, but there were no consistent trends with enzyme exposure.

Adult↗
PubMed1997

Effect of inspiratory flow rate on respiratory rate in intubated ventilated patients.

It has previously been demonstrated that in normal subjects using a volume-cycled ventilator, increasing inspiratory flow rate increases respiratory rate. We undertook the current study to determine (1) whether this effect is also present in patients with respiratory disease and (2) whether the effect is independent of upper airway receptors. Eight ventilator-dependent patients in the intensive care unit were studied. Patients were ventilated in the assist-control mode with the back-up rate set at 0.5 breaths/min to ensure that all breaths were patient-triggered. While tidal volume was held constant, flow was changed from a baseline flow of 60 L/min. Trials involved changing flow to either 30 or 90 L/min. There was a significant decrease in respiratory rate (-3.4 +/- 0.6 min-1, p < 0.001) when flow was decreased from 60 to 30 L/min. There was a significant increase in respiratory rate (2.3 +/- 0.8 min-1, p < 0.05) when flow was increased from 60 to 90 L/min. As a result of the change in respiratory rate, TE (expiratory time) showed a variable response to changes in flow rate, with some patients actually demonstrating a reduced TE with higher flow rates. No patients experienced the increase in TE that would have been predicted without a change in respiratory rate. We conclude that in intubated ventilated patients, spontaneous respiratory rate is sensitive to inspiratory flow rate. This effect appears to be independent of upper airway receptors, since it was observed with a by-passed upper airway. The increase in respiratory rate seen at higher flow rates undermines attempts to increase TE by increasing flow rates. It may also cause a tendency toward respiratory alkalosis.

Adolescent↗
PubMed1997

Informing prescribing allocations at district level in England.

OBJECTIVES: To derive a predictive model based on the morbidity, demographic and socio-economic characteristics of district populations to explain variations in prescribing costs in England. METHOD: Inter-relations between morbidity, demographic, socio-economic, general practice supply characteristics and net ingredient cost per age, sex and temporary resident originated prescribing unit (ASTRO-PU) were explored statistically for 90 districts in England using 1994 cost data. The possibility of mutual inter-relationship between 'supply' and 'demand' was examined; then the associations between a range of factors and prescribing costs were estimated using ordinary least squares regression and the predictive power of the possible models was systematically examined. RESULTS: Whilst there was a relatively weak relationship between the supply factors that were measured, there did not appear to be any reciprocal relationship. Three parsimonious models estimated using ordinary least squares multiple regression techniques based on combinations of permanent sickness, low birth weight and the proportion of general practitioners registered for postgraduate certificate of education were identified. The models explained up to 61% of variation between districts in prescribing costs. CONCLUSIONS: 'Need' and 'supply' characteristics are independently associated with variations in prescribing costs at district level. The negative association between the proportion of general practitioners eligible for postgraduate education allowance and prescribing costs may reflect 'better' prescribing but could not be introduced into a resource allocation formula without introducing perverse incentives. The combination of permanent sickness and low birth weight complement each other by providing a proxy measure of morbidity mostly applicable to adult males (permanent sickness) and mothers (low birth weight being a measure of maternal health). These variables should be considered further for use in the process of allocating resources for prescribing to districts.

Cost Allocation↗