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Biomedical subjects

J S Thomas

Publications and source records attributed to J S Thomas.

At least 19 recordsLinked to original sources
PubMed2006

Haemodynamic effects of oxytocin given as i.v. bolus or infusion on women undergoing Caesarean section.

BACKGROUND: The cardiovascular effects of oxytocin in animal models and women undergoing Caesarean section include tachycardia, hypotension and decrease in cardiac output. These can be sufficient to cause significant compromise in high-risk patients. We aimed to find a simple way to decrease these risks whilst retaining the benefits of oxytocin in decreasing bleeding after delivery. Method. We recruited 30 women undergoing elective Caesarean section. They were randomly allocated to receive 5 u of oxytocin either as a bolus injection (bolus group) or an infusion over 5 min (infusion group). These women had their heart rate and intra-arterial blood pressure recorded every 5 s throughout the procedure. The haemodynamic data, along with the estimated blood loss, were compared between the groups. RESULTS: Marked cardiovascular changes occurred in the bolus group; the heart rate increased by 17 (10.7) beats min(-1) [mean (sd)] compared with 10 (9.7) beats min(-1) in the infusion group. The mean arterial pressure decreased by 27 (7.6) mm Hg in the bolus group compared with 8 (8.7) mm Hg in the infusion group. There were no differences in the estimated blood loss between the two groups. CONCLUSION: We recommend that bolus doses should be used with caution, and further studies should ascertain if oxytocin is equally effective in reducing blood loss when given at a slower rate.

Adult↗
PubMed2004

Is the nuclear spin-orbit interaction changing with neutron excess?

The difference in the energies of the lowest states corresponding to the two nodeless single-particle orbitals outside the Z=50 closed proton shell, h(11/2) and g(7/2), increases with neutron excess. We have measured the Sn(alpha,t) reaction for all seven stable even Sn isotopes and found that the spectroscopic factors are constant for these two states, confirming their characterization as single-particle states. The trend in energies is consistent with a decrease in the nuclear spin-orbit interaction. A similar trend, also suggesting a decreasing spin-orbit splitting, is seen in the energies of the neutron single-particle states outside the N=82 core, i(13/2) and h(9/2).

Journal Article↗
PubMed2004

Strategic options for sustainable water management at new developments: the application of a simulation model to explore potential water savings.

Research on appropriate technologies and infrastructures to support water reuse has progressed rapidly over recent decades and there are now a wide range of source--treatment--reuse options for planners to choose from. Although the economics of water reuse schemes favours application to new developments rather than retrofit projects, there are few studies which have sought to address strategic option selection issues for large developments. The potential advantages of using treatment and reuse systems in new developments require an understanding of the relationships between a wide variety of social, environmental, technological, and operational factors. The operational effectiveness and economic efficiency of specific technology choices will vary as a function of network configuration, wastewater characteristics, how different technologies respond to dynamic loading (variability of feed strength and flow) and potential spiking, as well as equipment reliability, climate and household behaviour. Using a commercially available software package, the study reports the design and implementation of a low resolution simulation tool to explore sustainable water management options for a live case study site in the south of England (a peri-urban development of 4,500 new homes) with particular reference to opportunities for rainwater harvesting, and water reuse.

Climate↗
PubMed2002

SIRRUS: evaluation software of the technical and economic profitability of rainwater on an industrial site.

In a sustainable development context, the storm water reuse in industry seems a promising and original alternative, but few experiences exist. A project, sponsored by the European Community and the Artois-Picardie Water Agency, has been carried out by the Renault MCA factory in Maubeuge, demonstrating that it can be profitable, in certain conditions, to reuse storm water in industrial processes. This article summarises this experience, and presents a decision making tool (SIRRUS) that has been developed in this framework by Anjou Recherche (Vivendi Water) to evaluate, on the basis of simple criteria, if this experience is or is not reproducible on a given site, and how much time is necessary to pay the investment back. Its application and different results are also discussed.

Cost-Benefit Analysis↗
PubMed2001

Seasonal abundance of aphids (Homoptera: Aphididae) in wheat and their role as barley yellow dwarf virus vectors in the South Carolina coastal plain.

Aphid (Homoptera: Aphididae) seasonal flight activity and abundance in wheat, Triticum aestivum L., and the significance of aphid species as vectors of barley yellow dwarf virus were studied over a nine-year period in the South Carolina coastal plain. Four aphid species colonized wheat in a consistent seasonal pattern. Greenbug, Schizaphis graminum (Rondani), and rice root aphid, Rhopalosiphum rufiabdominalis (Sasaki), colonized seedlingwheat immediately after crop emergence, with apterous colonies usually peaking in December or January and then declining for the remainder of the season. These two aphid species are unlikely to cause economic loss on wheat in South Carolina, thus crop managers should not have to sample for the subterranean R. rufiabdominalis colonies. Bird cherry-oat aphid, Rhopalosiphum padi (L.), was the second most abundant species and the most economically important. Rhopalosiphum padi colonies usually remained below 10/row-meter until peaking in February or March. Barley yellow dwarf incidence and wheat yield loss were significantly correlated with R. padi peak abundance and aphid-day accumulation on the crop. Based on transmission assays, R. padi was primarily responsible for vectoring the predominant virus serotype (PAV) we found in wheat. Pest management efforts should focus on sampling for and suppressing this aphid species. December planting reduced aphid-day accumulation and barley yellow dwarf incidence, but delayed planting is not a practical management option. English grain aphid, Sitobion avenae (F.), was the last species to colonize wheat each season, and the most abundant. Sitobion avenae was responsible for late-season virus transmission and caused direct yield loss by feeding on heads and flag leaves during an outbreak year.

Animals↗
PubMed2000

Effects of a lifting belt on spine moments and muscle recruitments after unexpected sudden loading.

STUDY DESIGN: Ten men and eight women participated in a repeated-measures experiment in which sudden loads were applied unexpectedly to a container held in the hands. Three independent variables were investigated: lifting belt use, preload, and load symmetry. OBJECTIVES: To determine whether a lifting belt would help protect the spine in sudden symmetric and asymmetric loading situations. SUMMARY OF BACKGROUND DATA: Unexpected loading events have long been associated with the onset of back pain. Based on work showing that lifting belts restrict motion of the torso, the hypothesis was that a lifting belt would stiffen the spine, thereby protecting its supporting tissues. METHODS: A weight, equal to 7.5% of the subjects' trunk extension force, was allowed to fall 1 m before the bottom of a box held by blindfolded subjects was pulled. Kinetic and kinematic data, obtained from two force plates and a magnetic motion measurement system, were used in a three-dimensional, dynamic, linked-segment biomechanical model to calculate spine moments. Electromyogram data were simultaneously obtained from eight trunk muscles. RESULTS: The belt reduced the forward bending of the spine during the symmetric loadings. In the men, the belt also reduced the forward flexion moment acting on the spine. The belt restricted lateral bending in the women and men, when the box was preloaded. The peak electromyogram amplitudes from posterior contralateral erector spinae and latissimus dorsi muscles increased during the asymmetric loadings, whereas three ipsilateral muscles were less active. CONCLUSIONS: The conflicting moment and electromyographic results, combined with the influence of load symmetry, preload, and gender make the benefits of the lifting belt difficult to delineate. Although the data support the hypothesis that the belt stiffens the torso's response to sudden loading, the effects are small, and considerable individual differences exist. The findings show that during unexpected sudden loading, a belt may reduce the net external moment loading. At the same time the belt appears to alter the muscle response strategy so that the belt's overall effect on an individual's safety is hard to determine.

Adult↗
PubMed1999

Effect of lifting belts on trunk muscle activation during a suddenly applied load.

The National Institute for Occupational Safety and Health suggests there is insufficient biomechanical or epidemiological evidence to recommend the use of back belts in industry. From a biomechanical perspective, previous work suggests that lifting belts stiffen the torso, particularly in the frontal and transverse planes. To determine whether lifting belts stiffen the torso and alter the trunk muscle response during a sudden loading event, we tested the hypotheses that (a) lifting belts alter peak muscle activity recorded with electromyography (EMG) during sudden loading and (b) lifting belts have a larger impact on trunk muscle response when sudden loads are applied asymmetric to the torso's midsagittal plane. A sudden load was delivered to 10 men and 10 women without history of low back disorder via a cable attached to a thoracic harness; motion was restricted to the lumbar spine. Results indicate that gender was not a significant factor in this study. The lifting belt reduced the peak normalized EMG of the erector spinae muscles on average by 3% during asymmetric loading, though peak normalized EMG was increased by 2% during symmetric loading. Lifting belts have been shown to slightly reduce peak erector spinae activity during asymmetric sudden loading events in a constrained paradigm; however, the effects of lifting belts are too small to provide effective protection of workers. Actual or potential applications include the assessment of lifting belts as protective devices in workers based on the effects of lifting belts on the trunk muscle activity.

Adult↗
PubMed1998

Clotting times and antithrombin III activity in cats with naturally developing diseases: 85 cases (1984-1994).

OBJECTIVE: To determine the prevalence of abnormalities of in vitro prothrombin time (PT) and activated partial thromboplastin time (APTT), or antithrombin III (ATIII) activity or all 3 variables in cats; and the association of abnormalities of these variables with naturally developing diseases or disorders. DESIGN: Retrospective study. ANIMALS: 85 cats from which blood had been obtained for measurement of a coagulation profile (PT, APTT, and ATIII activity) and concentration of fibrin degradation products. PROCEDURE: Medical records from the Texas A&M College of Veterinary Medicine were reviewed to determine clinical diagnosis, results of CBC and coagulation profile, and clinical evidence of abnormal bleeding or thrombotic disease. RESULTS: 38 cats had one or more abnormality in the coagulation profile; most had multiple abnormalities. Twenty of these 38 cats had concurrent thrombocytopenia. Thrombocytopenia was identified in 9 of 47 cats in which results of the coagulation profile were normal. Most cats did not have clinical evidence of a coagulation disorder, and testing had been requested as part of a diagnostic work-up or before surgery. Diseases commonly associated with laboratory evidence of a coagulation disorder, either singly or in combination, included hepatic disease, neoplasia, and systemic infections. CLINICAL IMPLICATIONS: On the basis of laboratory evidence, hemostatic disorders develop more commonly in cats than clinical signs would suggest. Coagulation profiles may be warranted in high-risk cats to alert clinicians to potential problems.

Animals↗
PubMed1998

Acute amiodarone-induced lung toxicity.

OBJECTIVE: To investigate any relationship between the pathological features of amiodarone-induced pulmonary toxicity (APT) and clinical use of amiodarone in patients dying from acute respiratory distress syndrome (ARDS). DESIGN: Retrospective study. Review of clinical and pathological findings of patients dying from ARDS. SETTING: Intensive Care Unit (ICU) and Pathology Department of University hospital. SUBJECTS: Ten patients with clinical diagnosis of ARDS, who died in ICU and underwent post mortem examination. INTERVENTIONS: Case note review of clinical details; independent review of histological specimens. MEASUREMENT AND RESULTS: Over a 3-year period, ten patients underwent post mortem examination, of whom seven had received amiodarone. Three patients who received longer than 48 h of amiodarone had histological changes of widespread lipoid pneumonia, a recognised pattern of APT. CONCLUSIONS: Acute amiodarone pulmonary toxicity is a definite pathological entity in ICU patients. High oxygen concentrations may be a risk factor, while pre-existing pathology, e. g. ARDS, may mask its development. Amiodarone should be used with caution in this group of patients.

Adult↗
PubMed1998

Trunk kinematics and trunk muscle activity during a rapidly applied load.

This study investigated the trunk kinematics and electromyographic (EMG) activity of eight trunk muscles when "expected" and "unexpected" loads were applied directly to the torso. Twenty individuals (mean age: 25.1 yr; range 20-33 yr) participated in this mixed model study in which gender was the between-subjects factor, and expectancy and symmetry of the applied load were within-subject factors. The sudden load was delivered to the subject via a cable attached to a thoracic harness and motion was restricted to the lumbar spine by strapping the pelvis to a rigid fixation apparatus. Surface EMG was recorded bilaterally from the longissimus thoracis (LGT), erector spinae (ERS), rectus abdominis (RAB) and the external obliques (EXO). Trunk kinematics were measured with a Lumbar Motion Monitor. During expected loading conditions, the peak muscle activity was reduced for the RAB and EXO bilaterally, and for the ERS(R) (p < 0.01) relative to the unexpected conditions. Conversely, the normalized area of EMG activity prior to the onset of load was increased for the ERS and EXO bilaterally, and for the RAB(R) (p < 0.05) during an expected loading event. Trunk motion in the sagittal and frontal planes was reduced during expected loading. Activation of the trunk muscles just prior to a rapid loading event increases trunk stiffness, decreasing trunk displacement and peak muscle activity.

Adult↗
PubMed1997

The alpha4beta1 integrin can mediate leukocyte adhesion to casein and denatured protein substrates.

An understanding of the binding specificity of leukocyte integrins is important to determine the range of ligands that interact with these receptors during inflammatory processes. In this study we show that the alpha4beta1 integrin can interact with casein and denatured albumin and promote leukocyte adhesion through these interactions. This was demonstrated with the use of blocking antibodies directed to alpha4beta1 and peptide adhesion competitors containing the alpha4beta1 binding tripeptide, Leu-Asp-Val (LDV). Consistent with this data, the adhesion is completely divalent cation-dependent and is stimulated by known activators of leukocyte integrin function, namely phorbol ester and the beta1 integrin activating antibody, 8A2. It is interesting to note that neither bovine alpha-casein or human albumin contain an LDV site (present in the CS-1 site of alternatively spliced fibronectin) or an IDS site (present in VCAM-1) yet they promote adhesion through this integrin. Furthermore, alpha4beta1 directly binds to Sepharose columns containing casein, casein fragments, or denatured albumin but does not bind columns containing native albumin. These data suggest that the binding specificity for the alpha4beta1 integrin is considerably broader than previously realized. This work has implications for how subsets of leukocytes may interact with damaged proteins during tissue injury and inflammation.

Amino Acid Sequence↗
PubMed1996

von Willebrand's disease in the dog and cat.

Von Willebrand's disease (vWD) is a bleeding disorder that is recognized commonly in dogs but rarely in cats. This article presents the pathophysiology and clinical features of vWD, including a discussion of inherited and acquired types of vWD. Laboratory evaluation and treatment of vWD are reviewed.

Animals↗
PubMed1996

Successful urgent cerclage in a quadruplet gestation.

Pregnancies complicated by quadruplets are rare but at high risk for premature cervical dilation, premature deliveries, and increased perinatal mortality. This report presents a case of a patient carrying quadruplets whose cervix became 4 cm dilated at 21 weeks even though there were no reported uterine contractions. Despite bed rest and combination tocolytic therapy, the cervix dilated to 6 cm and the membranes protruded. Described here are refinements of an Olatunbosun technique to successfully perform the cerclage. Labor occurred at 32 weeks, and a cesarean delivery was performed before the transvaginal removal of the cerclage. The four appropriately-grown fetuses adjusted well in the intensive care nursery.

Adult↗
PubMed1996

The Scottish Royal Colleges: a prospective survey of continuing medical education undertaken by their examiners.

OBJECTIVE: To measure the amount and nature of Continuing Medical Education (CME) activity undertaken by the examiners of the three Scottish Royal Colleges. The data obtained to be compared with recommendations for formal CME participation published by the medical Royal Colleges and Faculties. DESIGN: All examiners in active clinical practice prospectively surveyed over a 12 month period by completing a monthly return from a specially designed loose-leaf diary. RESULTS: 75% of the examiners who submitted all 12 monthly diary pages completed at least 100 hours CME during the year while 95% achieved 50 hours or more. This time was distributed approximately equally between hospital-based activities and activities for which study leave might have been taken. Although the mean total number of hours of CME undertaken by consultants based in district general hospitals was also over 100 hours in the year, this was significantly lower than the figure for teaching hospital consultants. The type of CME activity was described as general (16%), specialty (49%) and subspecialty (35%). The examiners surveyed found that specialist society and international specialist meetings were perceived to be the most valuable of those attended. CONCLUSIONS: The current recommendations for implementing formal CME systems for consultants are in line with the current activity levels of this group and should safeguard existing educational activity rather than impose new standards. This study suggests that the profession should not be unduly anxious about the introduction of a structured CME system although it is likely that some form of obligatory scheme will be required to achieve a more uniform response.

Education, Medical, Continuing↗
PubMed1995

Effect of lifting belts, foot movement, and lift asymmetry on trunk motions.

Whether or not lifting belts protect workers from injury is a topic of considerable interest in industry. Not only is the protective effect uncertain, but the biomechanical basis for belt function is unclear. The objective of this study was to determine if lifting belts provide a means for controlling trunk motions during asymmetric material-handling tasks. We recruited 16 nursing personnel as experienced lifters to participate in two lifting sessions. A lifting belt was worn in one session and for a week prior to this session during the subjects' routine work activities. Each session required 42 lifts, distributed across three asymmetry conditions (0, 45, and 90 deg) and temporally spaced 30 s apart. Foot motion was not permitted in half the lifts. Results indicated that during lifting, lateral bending and twisting motions were reduced by both the lifting belt and foot motion; the most pronounced effect was observed at 90 deg of asymmetry. Trunk motions in the sagittal plane during lifting were not affected by the lifting belt. These results appear to support the use of lifting belts in asymmetric lifting conditions, but more research is needed to determine whether the muscles in the torso benefit from the reduced motion or are working harder to overcome this resistance to motion, causing increased internal loads on the spine during asymmetric material-handling tasks.

Adult↗