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Biomedical subjects

B Davies

Publications and source records attributed to B Davies.

At least 19 recordsLinked to original sources
PubMed2006

Development of a healthy biscuit: an alternative approach to biscuit manufacture.

OBJECTIVE: Obesity (BMI >30) and related health problems, including coronary heart disease (CHD), is without question a public health concern. The purpose of this study was to modify a traditional biscuit by the addition of vitamin B6, vitamin B12, Folic Acid, Vitamin C and Prebiotic fibre, while reducing salt and sugar. DESIGN: Development and commercial manufacture of the functional biscuit was carried out in collaboration with a well known and respected biscuit manufacturer of International reputation. The raw materials traditionally referred to as essential in biscuit manufacture, i.e. sugar and fat, were targeted for removal or reduction. In addition, salt was completely removed from the recipe. PARTICIPANTS: University students of both sexes (n = 25) agreed to act as subjects for the study. Ethical approval for the study was granted by the University ethics committee. The test was conducted as a single blind crossover design, and the modified and traditional biscuits were presented to the subjects under the same experimental conditions in a random fashion. RESULTS: No difference was observed between the original and the modified product for taste and consistency (P > 0.05). The modified biscuit was acceptable to the consumer in terms of eating quality, flavour and colour. Commercial acceptability was therefore established. CONCLUSION: This study has confirmed that traditional high-fat and high-sugar biscuits which are not associated with healthy diets by most consumers can be modified to produce a healthy alternative that can be manufactured under strict commercial conditions.

Cross-Over Studies↗
PubMed2006

Homocysteine induced cardiovascular events: a consequence of long term anabolic-androgenic steroid (AAS) abuse.

OBJECTIVES: The long term effects (>20 years) of anabolic-androgenic steroid (AAS) use on plasma concentrations of homocysteine (HCY), folate, testosterone, sex hormone binding globulin (SHBG), free androgen index, urea, creatinine, haematocrit (HCT), vitamin B12, and urinary testosterone/epitestosterone (T/E) ratio, were examined in a cohort of self-prescribing bodybuilders. METHODS: Subjects (n = 40) were divided into four distinct groups: (1) AAS users still using AAS (SU; n = 10); (2) AAS users abstinent from AAS administration for 3 months (SA; n = 10); (3) non-drug using bodybuilding controls (BC; n = 10); and (4) sedentary male controls (SC; n = 10). RESULTS: HCY levels were significantly higher in SU compared with BC and SC (p<0.01), and with SA (p<0.05). Fat free mass was significantly higher in both groups of AAS users (p<0.01). Daily energy intake (kJ) and daily protein intake (g/day) were significantly higher in SU and SA (p<0.05) compared with BC and SC, but were unlikely to be responsible for the observed HCY increases. HCT concentrations were significantly higher in the SU group (p<0.01). A significant linear inverse relationship was observed in the SU group between SHBG and HCY (r = -0.828, p<0.01), indicating a possible influence of the sex hormones in determining HCY levels. CONCLUSIONS: With mounting evidence linking AAS to adverse effects on some clotting factors, the significantly higher levels of HCY and HCT observed in the SU group suggest long term AAS users have increased risk of future thromboembolic events.

Adult↗
PubMed2006

Role of epididymal receptor HE6 in the regulation of sperm microenvironment.

HE6 (GPR64) is a highly conserved, tissue-specific heptahelical receptor of the human epididymis. The seven transmembrane (TM7) domains are a hallmark of G-protein-coupled receptors (GPCRs) which have a proven history of being excellent therapeutic targets. Of all currently marketed drugs, >30% are modulators of specific heptahelical receptors, emphasizing the potential of HE6 as a target for pharmaceutical intervention. Targeted mutation of the mouse HE6 counterpart resulted in male infertility, further emphasizing its role as a candidate target for male contraception. However, the precise function of HE6, together with its potential ligand(s), and signal transduction pathways have remained largely unknown. On the basis of shared sequence motifs within the TM7 region, HE6 has been grouped into the B class of GPCRs. Within this class, HE6 belongs to the 'large N-termini' family-B seven-transmembrane (LNB-TM7) receptors, also termed the adhesion-GPCRs. Members of this subgroup are 'orphan' receptors, and they all seem to be cleaved within a conserved GPCR proteolytic site (GPS) domain. The biological significance of the two-subunit architecture is still unknown. Clues to the function of HE6 within the epithelium of male excurrent ducts may come from its co-localisation with the apical actin cytoskeleton and from the down-regulation in "knockout" male mice of various proteins specific to the initial segment.

Amino Acid Sequence↗
PubMed2006

Steroid and prescription medicine abuse in the health and fitness community: A regional study.

BACKGROUND: The purpose of this study was to identify the prevalence of abuse of certain prescription medicines (POM) amongst health club attendees. The non-therapeutic use of such medicines has previously been considered to be restricted to the professional athlete. METHODS: In the summer of 2005, health club users in the South Wales area were given questionnaires and asked to return them in a stamped, addressed envelope. Anonymity of the respondents was assured. RESULTS: From the distribution of 210 questionnaires, the response rate was 69.5% (146 questionnaires). The mean age of the sample was 33.6+/-6.7 years (range 15-72 years). Anabolic-androgenic steroid (AAS) use is prominent amongst recreational gym users in this regional sample, with 70% (102 individuals) reporting AAS use, 65.8% (96 individuals) of whom were currently still using. Some 7% of respondents (10 individuals) were female and they also reported taking medication. This research demonstrated an enormous increase in the use of growth hormone (24%), insulin (14%), and tamoxifen (22%), with smaller increases in other drugs. CONCLUSION: Drug users were from all levels of society and reported various physiological and psychological side effects from their use. The present study indicated that the most used medicine/drug from less than reputable sources was still AAS but that, as a consequence of the internet revolution, they were being caught up by the more expensive designer drugs, particularly growth hormone. Physicians and medical personnel must become aware that the use of AAS and other prescription medicines is on the increase and appears to be predominantly used for cosmetic reasons.

Journal Article↗
PubMed2006

A review of magnetic resonance imaging compatible manipulators in surgery.

Developments in magnetic resonance imaging (MRI), coupled with parallel progress in the field of computer-assisted surgery, mean that an ideal environment has been created for the development of MRI-compatible robotic systems and manipulators, capable of enhancing many types of surgical procedure. However, MRI does impose severe restrictions on mechatronic devices to be used in or around the scanners. In this article a review of the developments in the field of MRI-compatible surgical manipulators over the last decade is presented. The manipulators developed make use of different methods of actuation, but they can be reduced to four main groups: actuation transmitted through hydraulics, pneumatic actuators, ultrasonic motors based on the piezoceramic principle and remote manual actuation. Progress has been made concerning material selection, position sensing, and different actuation techniques, and design strategies have been implemented to overcome the multiple restrictions imposed by the MRI environment. Most systems lack the clinical validation needed to continue on to commercial products.

Equipment Design↗
PubMed2006

Hands-on robotic unicompartmental knee replacement: a prospective, randomised controlled study of the acrobot system.

We performed a prospective, randomised controlled trial of unicompartmental knee arthroplasty comparing the performance of the Acrobot system with conventional surgery. A total of 27 patients (28 knees) awaiting unicompartmental knee arthroplasty were randomly allocated to have the operation performed conventionally or with the assistance of the Acrobot. The primary outcome measurement was the angle of tibiofemoral alignment in the coronal plane, measured by CT. Other secondary parameters were evaluated and are reported. All of the Acrobot group had tibiofemoral alignment in the coronal plane within 2 degrees of the planned position, while only 40% of the conventional group achieved this level of accuracy. While the operations took longer, no adverse effects were noted, and there was a trend towards improvement in performance with increasing accuracy based on the Western Ontario and McMaster Universities Osteoarthritis Index and American Knee Society scores at six weeks and three months. The Acrobot device allows the surgeon to reproduce a pre-operative plan more reliably than is possible using conventional techniques which may have clinical advantages.

Aged↗
PubMed2005

Generation of Th1 T cell responses directed to a HLA Class II restricted epitope from the Aspergillus f16 allergen.

The Aspergillus allergen Asp f16 has been shown to confer protective Th1 T cell-mediated immunity against infection with Aspergillus conidia in murine models. Here, we use overlapping (11-aa overlap with preceding peptide) pentadecapeptides spanning the entire 427-aa coding region of Asp f16 presented on autologous dendritic cells (DC) to evaluate the ability of this antigen to induce Th1 responses in humans. Proliferative responses were induced in five out of five donors, and one line with a high frequency of interferon (IFN)-gamma-producing CD4(+) T cells in response to the complete peptide pool was characterized. This line was cytotoxic to autologous pool-pulsed and Aspergillus culture extract-pulsed targets. Limitation of cytotoxicity to the CD4(+) T cell subset was demonstrated by co-expression of the degranulation marker CD107a in response to peptide pool-pulsed targets. Cytotoxic T lymphocytes (CTL) killed Aspergillus hyphae and CTL culture supernatant killed Aspergillus conidia. By screening 21 smaller pools and individual peptides shared by positive pools we identified a single candidate sequence of TWSIDGAVVRT that elicited responses equal to the complete pool. The defined epitope was presented by human leucocyte antigen (HLA)-DRB1-0301. These data identify the first known Aspergillus-specific T cell epitope and support the use of Asp f16 in clinical immunotherapy protocols to prime protective immune responses to prevent or treat Aspergillus infection in immunocompromised patients.

Allergens↗
PubMed2005

Generation of cytotoxic T cell responses directed to human leucocyte antigen Class I restricted epitopes from the Aspergillus f16 allergen.

Invasive aspergillosis (IA) is a major cause of infection-related mortality in patients with haematological malignancies, especially in recipients of haematopoietic stem cell transplants. We have prepared overlapping pentadecapeptides (11-aa overlap with previous peptide) spanning the entire 427-aa coding region of the Aspergillus allergen, Asp f16 shown previously in mice to induce Th1-type cell responses in vivo and in humans to induce proliferative and cytotoxic CD4(+) T cell responses. Mature dendritic cells (DC) pulsed with a complete pool of peptides were used to generate T cell lines. Two lines from HLA-B*3501(+) donors were found to be strongly cytotoxic to autologous Asp f16-peptide pool- and Aspergillus culture extract-pulsed targets after 4-5 weekly primings. Cytotoxic T lymphocyte (CTL) culture supernatant killed Aspergillus conidia, and cells directly killed Aspergillus hyphae. Cytotoxic activity and interferon (IFN)-gamma production were mediated exclusively by CD8(+) T cells in response to pool-pulsed targets. Interleukin (IL)-4 production was not detected. CTL activity was restricted by HLA-B*3501 and based on peptide prediction programmes was most probably directed to YFKYTAAAL (YFK), LPLCSAQTW (LPL) and GTRFPQTPM (GTR) in one donor, while only LPL was recognized by CTL from the second donor. Pool-pulsed B*3503(+) BLCL but not B*3502(+) or B*3508(+) BLCL presented peptide to donor no. 1. B*3503(+) BLCL presented YFK and to a lesser extent GTR, but not peptide LPL. Our data show that in addition to our previously identified Class II restricted peptide response, DC pulsed with a pentadecapeptide pool from Asp f16 are capable of inducing polyclonal, HLA-Class I-restricted, Aspergillus-specific T cells that may be capable of conferring immunity to IA.

Allergens↗
PubMed2004

The effects of different inspiratory muscle training intensities on exercising heart rate and perceived exertion.

This study investigated the relationship between the intensity of an inspiratory muscle training programme and its effect on respiratory muscle strength, exercising heart rate, and ratings of perceived exertion. A total of 66 subjects were randomly assigned to one of three groups. One group trained at 100% of maximum inspiratory pressure (MIP) for 6 weeks (MAX, n=22). A second group performed 6 weeks of inspiratory muscle training at 80% of MIP (SUB, n=21) and a third control group received no inspiratory training (CON, n=23). Both the MAX and SUB training groups improved MIP relative to the control group [32 (19) cmH(2)O, P=0.01; 37 (25) cmH(2)O, P=0.001, respectively]. A significant decrease in heart rate [-6 (9) beats min(-1), P=0.02] and rating of perceived exertion [-0.5 (1.4), P=0.04] was observed for the MAX group only. It is concluded that 6 weeks of both MAX and SUB training were sufficient to improve inspiratory muscle strength. However, exercising heart rate and perceived exertion decreased with MAX training only.

Adaptation, Physiological↗
PubMed2004

Abdominal aortic aneurysm and its correlation to plasma homocysteine, and vitamins.

BACKGROUND: Hyperhomocysteinemia is a recognised independent risk factor in the genesis of atherosclerotic diseases. However, very little is known about the relationship between homocysteine and abdominal aortic aneurysm (AAA). Vitamins, namely B12 and folic acid have been implicated in the regulation of plasma homocysteine levels. However, there has been no prospective study that has analysed the relationship of AAA and plasma homocysteine in light of serum vitamin levels. AIMS: To study the relationship between plasma homocysteine, serum B12 and folic acid levels, and AAA. METHOD: Case control study including 38 AAA patients and 36 controls. Fasting homocysteine, B12 and folic acid were determined in serum separated within 1 h of blood collection using a fluorescence polarisation immunoassay technique (FPIA). RESULTS: Twenty-six (68%) of the AAA patients had elevated levels of homocysteine compared to 2 (6%) in the case control group. The mean homocysteine level in the AAA group was 19.4 micromol/L (SE +/- 1.1) (95% CI 17.17-21.65) and in the control group was 10.9 micromol/L (SE +/- 1) (95% CI 9.95-11.88) (p<0.001). Mean vitamin B12 levels in the AAA and the controls was 332.11 pg/L (SE +/- 16.44) and 414.33 pg/L (SE +/- 19.72), respectively (p<0.004). Mean folic acid in the AAA was 8.02 (SE +/- 0.71) and the control was 9.8 etagm/L (SE +/- 0.69), (ns). CONCLUSION: This study confirms significantly higher levels of plasma homocysteine in AAA patients but lower levels of B12. Use of supplemental vitamins that should lower plasma homocysteine may modify vascular disease progression. Clinical trials in this direction are warranted.

Aged↗
PubMed2004

Raised concentrations of C reactive protein in anabolic steroid using bodybuilders.

OBJECTIVE: To examine levels of C reactive protein in users of anabolic androgenic steroids (AAS) compared with age matched control groups consisting of AAS using (but abstinent)/resistance trained and non-drug using/sedentary controls. METHOD: Subjects included AAS using bodybuilders (n = 10); bodybuilders who denied AAS use (n = 10); sedentary controls (n = 8). Venous blood was sampled, from which serum concentrations of C reactive protein, male sex hormones, and cardiac troponin T were determined. RESULTS: A significantly altered hormonal profile in the AAS using group provided indirect confirmation of AAS use. C reactive protein concentrations were significantly (p<0.05) higher in the AAS using bodybuilders. There was no relation between C reactive protein and cardiac troponin T. CONCLUSION: AAS using bodybuilders had significantly higher C reactive protein concentrations, indicating a greater propensity to develop peripheral arterial disease.

Anabolic Agents↗
PubMed2004

Inspiratory resistive loading improves cycling capacity: a placebo controlled trial.

BACKGROUND: Respiratory muscle training has been shown to improve both its strength and endurance. The effect of these improvements on whole-body exercise performance remains controversial. OBJECTIVE: To assess the effect of a 10 week inspiratory resistive loading (IRL) intervention on respiratory muscle performance and whole-body exercise endurance. METHODS: Fifteen apparently healthy subjects (10 men, 5 women) were randomly allocated to one of three groups. One group underwent IRL set at 80% of maximum inspiratory pressure with ever decreasing work/rest ratios until task failure, for three days a week for 10 weeks (IRL group). A second placebo group performed the same training procedure but with a minimal resistance (PLA group). IRL and placebo training were performed at rest. The remaining five control subjects performed no IRL during the 10 week study period (CON group). Cycling endurance capacity at 75% VO(2)peak was measured before and after the intervention. RESULTS: After the 10 week IRL intervention, respiratory muscle strength (maximum inspiratory pressure) and endurance (sum of sustained maximum inspiratory pressure) had significantly improved (by 34% and 38% respectively). An increase in diaphragm thickness was also observed. These improvements translated into a 36% increase in cycling time to exhaustion at 75% VO(2)peak. During cycling trials, heart rate, ventilation, and rating of perceived exertion were attenuated in the IRL group. No changes were observed for the PLA or CON group either in the time to exhaustion or cardiorespiratory response to the same intensity of exercise. CONCLUSION: Ten weeks of IRL attenuated the heart rate, ventilatory, and perceptual response to constant workload exercise, and improved the cycling time to exhaustion. Familiarisation was not a factor and the placebo effect was minimal.

Adult↗
PubMed2004

Emergency ultrasound in the acute assessment of haemothorax.

AIMS: To evaluate thoracic ultrasound for the detection of haemothorax in patients with thoracic trauma against established investigations. METHODS: Thoracic ultrasound was performed as an extension of the standard focused assessment with sonography for trauma (FAST) protocol used at the Queen's Medical Centre for the assessment of adult patients with torso trauma. Fluid was sought in both pleural cavities using a hand portable ultrasound system by one of two non-radiologists trained in FAST. Findings were compared against subsequent investigations/procedures performed at the discretion of the attending emergency physician-supine chest radiography, intercostal drain, computed tomography, or thoracotomy. The sensitivity of the technique and the time taken to diagnosis for each investigation were recorded. RESULTS: Sixty one patients, 54 (89%) after blunt trauma, underwent thoracic ultrasound evaluation during the study. Twelve patients had a haemothorax detected by ultrasound and confirmed by computed tomography or by tube thoracostomy. Four haemothoraces detected on ultrasound were not apparent on trauma chest radiography. There were 12 true positives, 48 true negatives, no false positives, and one false negative scan. The sensitivity of ultrasound was 92% and specificity 100% with a positive predictive value of 100% and negative predictive value 98% for the detection of haemothorax after trauma. CONCLUSIONS: Emergency ultrasound of the chest performed as part of the primary survey of the traumatised patient can rapidly and accurately diagnose haemothorax and is a valuable tool to augment the immediate clinical assessment of these patients.

Acute Disease↗
PubMed2004

Prospective evaluation of non-radiologist performed emergency abdominal ultrasound for haemoperitoneum.

OBJECTIVES: To evaluate non-radiologist performed emergency ultrasound for the detection of haemoperitoneum after abdominal trauma in a British accident and emergency department. METHODS: Focused assessment with sonography for trauma (FAST) was performed during the primary survey on adult patients triaged to the resuscitation room with suspected abdominal injury over a 12 month period. All investigations were performed by one of three non-radiologists trained in FAST. The ultrasound findings were compared against the investigation of choice of the attending surgeon/accident and emergency physician. The patients were followed up for clinically significant events until hospital discharge or death. RESULTS: One hundred patients who had sustained blunt abdominal trauma, were evaluated by FAST. Nine true positive scans were detected and confirmed by computed tomography, diagnostic peritoneal lavage, or laparotomy. There was one false positive in this group, giving a sensitivity of 100%, specificity 99%, and positive predictive value of 90%. Ten patients with penetrating injuries were evaluated with a sensitivity and specificity for FAST of 33% and 86% respectively. CONCLUSIONS: Emergency torso ultrasound for the detection of haemoperitoneum can be successfully performed by trained non-radiologists within a British accident and emergency system. It is an accurate and rapid investigation for blunt trauma, but the results should be interpreted with caution in penetrating injury.

Abdominal Injuries↗
PubMed2004

Effects on respiratory health of a reduction in air pollution from vehicle exhaust emissions.

AIMS: To determine whether residents of congested streets have a higher prevalence of respiratory symptoms than residents of nearby uncongested streets, and whether their respiratory health improves following a reduction in exposure to traffic related air pollutants. METHODS: An area was identified where certain streets were subject to air pollution from heavy road traffic, which was likely to improve following the construction of a by-pass. A respiratory survey was conducted among the residents, together with the residents of nearby uncongested streets, at baseline and again a year after the by-pass opened. Measurements were made of air pollutant concentrations in both areas on both occasions. RESULTS: Initial concentrations of PM10 and PM2.5 were substantially higher in the congested than in the uncongested streets. When the by-pass opened, the volume of heavy goods traffic fell by nearly 50%. PM10 decreased by 23% (8.0 microg/m3) in the congested streets and by 29% (3.4 microg/m3) in the uncongested streets, with similar proportionate falls in PM2.5. There were no clear or consistent differences between the residents of the two areas initially in terms of symptoms or peak flow variability. Repeat questionnaires were obtained from 165 and 283 subjects in the congested and uncongested areas respectively, and showed a tendency for most symptoms to improve in both areas. For chest symptoms, the improvement tended to be greater in the uncongested area, although the difference between the areas was not statistically significant. Rhinitis and rhinoconjunctivitis tended to improve to a greater extent in the congested streets; the difference between the areas was significant for the degree to which rhinitis interfered with daily activities. Peak flow variability tended to improve in the uncongested area. CONCLUSIONS: The by-pass reduced pollutant levels to a degree that probably alleviates rhinitis and rhinoconjunctivitis but has little effect on lower respiratory symptoms.

Air Pollutants↗
PubMed2004

Emergency surgery in patients in extremis from blunt torso injury: heroic surgery or futile care?

BACKGROUND: Trauma strikes unexpectedly, frequently in the young and fit. When trauma victims arrive in the emergency room all possible steps, including surgery, are often undertaken in an attempt to achieve a successful outcome. However, for patients presenting in extremis, with cardiac arrest or exsanguinating blunt chest injury, the results of resuscitation and emergency surgery are extremely poor. PATIENTS AND SETTING: Eight patients in extremis with a mean injury severity score of 36, presented to the resuscitation room of Queens Medical Centre during 2001. On arrival all were in extremis or cardiac arrest after significant blunt injury to the torso, and during resuscitation had a brief loss of cardiac output. They underwent emergency surgery to control haemorrhage and correct injuries in an attempt to preserve life. Seven patients died within hours of their initial presentation either in theatre or the intensive care unit and one patient survived. CONCLUSIONS: Futile care in the management of severely injured patients is a controversial concept although the literature defines four concepts of futility within surgery. At present, while there remains even the remotest possibility of survival, there remains a strong incentive to act and reports of isolated survivors from studies of trauma patients in extremis or cardiac arrest continue to emerge. This may be seen as justification for either an aggressive surgical approach or an indication that surgery is futile. In an emerging culture of guidelines regarding effectiveness of treatment, is this an area in which such guidelines can or should be applied?

Accidents, Traffic↗