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Biomedical subjects

A Taylor

Publications and source records attributed to A Taylor.

At least 73 records · Page 4Linked to original sources
PubMed2004

Investigation of fatigue crack growth in acrylic bone cement using the acoustic emission technique.

Failure of the bone cement mantle has been implicated in the loosening process of cemented hip stems. Current methods of investigating degradation of the cement mantle in vitro often require sectioning of the sample to confirm failure paths. The present research investigates acoustic emission as a passive experimental method for the assessment of bone cement failure. Damage in bone cement was monitored during four point bending fatigue tests through an analysis of the peak amplitude, duration, rise time (RT) and energy of the events emitted from the damage sections. A difference in AE trends was observed during failure for specimens aged and tested in (i) air and (ii) Ringer's solution at 37 degrees C. It was noted that the acoustic behaviour varied according to applied load level; events of higher duration and RT were emitted during fatigue at lower stresses. A good correlation was observed between crack location and source of acoustic emission, and the nature of the acoustic parameters that were most suited to bone cement failure characterisation was identified. The methodology employed in this study could potentially be used as a pre-clinical assessment tool for the integrity of cemented load bearing implants.

Acoustics↗
PubMed2004

Juvenile neuronal ceroid lipofuscinosis (Batten disease) CLN3 mutation (Chrom 16p11.2) with different phenotypes in a sibling pair and low intensity in vivo autofluorescence.

BACKGROUND: The neuronal ceroid lipofuscinoses (Batten disease) are a heterogeneous group of autosomal recessively inherited disorders causing progressive neurological failure, mental deterioration, seizures and visual loss secondary to retinal dystrophy. The juvenile type is of special interest to the ophthalmologist as visual loss is the earliest symptom of the disorder. HISTORY AND SIGNS: We present two siblings with severe retinal dystrophy due to juvenile Batten disease. Sibling A (age 10) presented with visual loss, photophobia and night blindness, starting at age 4. His vision was perception of light by the age of 10.5 years. Fundus examination revealed severe pigmentary retinopathy. Sibling B (age 7) presented with night vision difficulties. Fundus examination revealed a bull's eye maculopathy with minimal peripheral atrophic changes. In vivo autofluorescence level was found to be very low. Electroretinography (ERG) showed generalized retinal dysfunction involving both cone and rod systems, with an electronegative maximal response. In both siblings vacuolated lymphocytes were found on a peripheral blood film and on molecular genetic testing both were homozygous for the commonly reported 1.02-kb deletion of the CLN3 gene. THERAPY AND OUTCOME: Although there is no effective treatment, the early diagnosis allowed accurate genetic and social counseling. CONCLUSIONS: Juvenile Batten disease should be considered in children with a retinal dystrophy, especially where there is a bull's eye maculopathy and an abnormal full field ERG. The novel finding of very low in vivo autofluorescence is consistent with histopathological studies and may be secondary to photoreceptor cell loss.

Blindness↗
PubMed2004

Hepatitis A virus and injecting drug misuse in Aberdeen, Scotland: a case-control study.

To describe an epidemiological investigation of an outbreak of hepatitis A virus (HAV) infection among injecting drug users in Aberdeen, Scotland. A case-control study to determine whether transmission was facilitated by poor personal hygiene or through sharing injecting equipment. Cases were more likely to report not washing their hands after using the toilet [odds ratio (OR) = 12.9, 95% confidence interval (CI) = 1.58-105.89] or before preparing food (OR = 4.0, 95% CI = 1.01-15.8), and less likely to have washed their hands prior to preparing drugs (OR = 10.67, 95% CI = 2.14-53.07). Cases were also more likely to report recipient sharing of needles/syringes (OR = 8.27, 95% CI = 1.68-40.57), and to have had injecting contact with someone who was jaundiced (OR = 29.4, 95% CI = 3.18-271.44). The results indicate that the lack of hygiene within the context of individuals gathering to prepare and inject drugs provides ample opportunity for the transmission of HAV. Although the promotion of good hygiene and the avoidance of sharing injecting equipment are important measures in preventing HAV transmission, they are unlikely to effect major behavioural change. Such measures should, therefore, be reinforced by routinely offering HAV vaccine to injectors.

Adolescent↗
PubMed2004

Developing a rapid diagnosis and treatment centre: estimating impact on hospital resources.

OBJECTIVES: To determine the possible impact on hospital bed occupancy if a "rapid diagnosis and treatment centre" (RDTC) were operational; to determine the number of patients that such a unit should be able to accommodate to avoid delays in transfer to this unit. DESIGN: Retrospective review of accident and emergency (A&E) department notes from consecutive adults over a 16 day period. SETTING: City centre teaching hospital with 1330 beds and 105 000 A&E new attendees per annum. MAIN OUTCOME MEASURES: Total number of bed days saved per annum (and daily average, assuming no variation by season or day of the week) and the expected occupancy of the RDTC according to the time of day. RESULTS: The expected daily bed saving was estimated to be 16. Average occupancy was expected to be between six and eight (with little diurnal variation) and a unit with 10 beds would be sufficiently large to avoid delays for 85% of patients transferred there from A&E. CONCLUSIONS: On the basis of a "paper exercise" an RDTC would be expected to be beneficial in terms of bed utilisation; careful evaluation of the effects of such a unit in operation should be undertaken.

Adult↗
PubMed2004

Iatrogenic copper deficiency following information and drugs obtained over the Internet.

We report the case of a 56-year-old woman with a 7-year history of metastatic cancer who presented with severe copper deficiency following self-treatment with the copper-chelating agent tetrathiomolybdate. This compound was used with the aim of inhibiting tumour angiogenesis and was obtained from the USA by placing an order on the internet. The patient exhibited severe neutropenia as her serum copper concentration fell from 19.8 micromol/L to 3.3 micromol/L and her caeruloplasmin concentration from 35 mg/dL to 4 mg/dL.

Copper↗
PubMed2004

Homozygous hypercholesterolaemia and ezetimibe: a case report.

UNLABELLED: A girl of Indian origin presented with unusual nodules on her hands, and total cholesterol was found to be > 25 mmol/L. The girl had "mild" P664L mutation and total cholesterol levels fell by 38% when she was on a diet and statin therapy. A further reduction of 26% in total cholesterol and 37% in low-density lipoprotein (LDL) was achieved by adding ezetimibe to the treatment. CONCLUSION: A case of homozygous hypercholesterolaemia is reported in order to highlight treatment options such as liver transplantation, LDL-aphaeresis and treatment with ezetimibe.

Anticholesteremic Agents↗
PubMed2003

The influence of bag2 and chain intrafusal muscle fibers on secondary spindle afferents in the cat.

Static gamma-motor activity is strongly modulated by a particular phase relationship to the cyclic movements of locomotion, and this has a profound effect on the firing patterns of muscle spindle afferents. Whilst primary afferents are affected by both static and dynamic gamma-motor output,secondary afferents are affected significantly only by the static system acting via the intrafusal bag2 and chain fibres. It is therefore important to know how fluctuating patterns of static gamma-motor activity affect secondary afferents and to relate this to the actions of bagt and chain fibres. We have studied the action of single static gamma axons on secondary afferents in cat hindlimb muscles. Various physiological methods were explored to identify which of the intrafusal muscle fibres were being activated in each case, including the use of random stimulation and ramp frequency stimulation. The effects were also recorded of I Hz sinusoidally frequency-modulated gamma-axon stimuli and the amplitude and phase of the resulting afferent modulation related to the involvement of the bag2 and chain fibres. It was found that bag2 fibres are effective in biasing the secondary discharge, but their modulating action is relatively weak and involves a marked phase lag. Chain fibres acting alone cause strong modulation with very little phase lag. Mixed bag2 and chain-fibre action is most effective in modulating afferent discharge and causes intermediate values of phase lag. The results are discussed in relation to the control of natural movements and it is concluded that an important function of the static gamma motor system is to provide a signal to sum algebraically with the length-related signal. The results do not suggest that it could also usefully control stretch sensitivity.

Animals↗
PubMed2003

Magnesium-creatine supplementation effects on body water.

This study evaluated magnesium-creatine (MgCre) supplementation on body water and quadriceps torque. Maltodextran (Placebo), Mg oxide plus Cre (MgO-Cre), and Mg-creatine chelate (MgC-Cre) at 800 mg Mg and 5 g Cre per day were used for 2 weeks in 35 subjects in a random assignment, blinded study. Pre-post measures were completed with bioimpedance to determine total body water (TBW), extracellular water (ECF), and intracellular water (ICF), and an isokinetic device at 180 degrees per second for knee extension peak torque (T), total work (W), and power (PWR). Body weights increased for both treatment groups, MgO-Cre Delta 0.75 kg (P <.05) and MgC-Cre Delta 0.4 kg (P =.07). Significant pre-post differences (P <.05) were noted only for MgC-Cre in ICW (26.29 v 28.01 L) and ECW (15.75 v 14.88 L). MgC-Cre had significant peak T (Nm) increase (124.5 v135.8, P <.05), while MgO-Cre (116.4 v 124.9, P =.06) and placebo (119.8 v 123.7, P =.343) did not. Both treatment groups had increased PWR (P <.05). MgC-Cre affects cellular fluid compartments. The peak torque changes were significant only in the MgC-Cre group, which had increases in ICW that may infer more muscular creatine due to its osmotic effect, and with increased cellular hydration, perhaps increased protein synthesis.

Adult↗
PubMed2003

A comparison of the reliability and validity of bone stock loss classification systems used for revision hip surgery.

Three femoral (Paprosky, American Academy of Orthopaedic Surgeons [AAOS], and Endo-Klinik) and 2 acetabular (Paprosky, AAOS) bone stock loss classification systems were evaluated for reliability. Four observers (2 consultants, 2 registrars) graded the bone loss in 25 patients using preoperative radiographs. Grading was repeated after a minimum of 2 weeks. Interobserver and intraobserver reliability was investigated. The kappa statistic was used to assess levels of agreement. Intraobserver agreement ranged from poor to good. Interobserver agreement ranged from fair to moderate. The validity of the Paprosky classification system was evaluated, comparing preoperative bone stock loss assessment with intraoperative findings. Agreement levels of moderate (femoral classification system) to good (acetabular classification system) were achieved. Bone stock loss classification systems are shown to be inconsistent and unreliable.

Arthroplasty, Replacement, Hip↗
PubMed2003

Treatment of graft-versus-host disease after liver transplantation with basiliximab followed by bowel resection.

Graft-versus-host disease (GVHD) after orthotopic liver transplantation (OLT) is a serious complication with mortality rates over 80%. Two patients with established GVHD after OLT were treated with Basiliximab, a chimeric murine human monoclonal antibody which binds to the alpha-chain of interleukin-2 receptor (IL-2R). Two males, aged 45 and 56 years, presented after OLT with a clinical picture consistent with GVHD. Quantitative measurements of recipient peripheral blood donor lymphocyte chimerism were carried out by flow cytometric analysis, and showed peak chimerism levels of 5% and 8%, respectively. Treatment comprised 3 doses of 1 g methyl prednisolone followed by 2 doses of 20 mg of Basiliximab. In both, treatment resulted in complete disappearance of macro-chimerism in blood. There was resolution of skin rash by day 7; however, diarrhea persisted. White cell scan showed increased uptake in the terminal ileum and small-bowel resection was performed in both patients. One patient is alive and well 36 months after OLT. The other patient had resolution of GVHD, but died of recurrent hepatitis C 1 year after OLT. The combination of immunological and surgical treatment for GVHD following solid organ transplantation has not previously been described.

Antibodies, Monoclonal↗
PubMed2003

Neonatal interleukin-12 capacity is associated with variations in allergen-specific immune responses in the neonatal and postnatal periods.

BACKGROUND AND OBJECTIVES: A reduced capacity of antigen presenting cells (APC) to provide pro-T helper 1 (Th1) signals, such as IL-12, to T cells during early life may be implicated in the development of T helper 2 (Th2)-mediated allergic disease. In this study we examined the relationships between the capacity for IL-12 responses in the neonatal period and atopic risk (family allergy), in vitro T cell responses to allergens, and the subsequent development of allergic disease at 6 years. METHODS: The capacity of circulating neonatal (and maternal) APC to produce IL-12 p70 in response to LPS (and IFN-gamma) stimulation was assessed in a group of 60 children with previously well-characterized immune responses to allergens and atopic outcomes. The IL-12 responses were compared with allergen-induced lymphoproliferation (to house dust mite (HDM) ovalbumin (OVA), cat and beta-lactoglobulin (BLG)) and IL-13 and IFN-gamma cytokine responses (to OVA, HDM and phytohaemaglutinin (PHA)) in the neonatal and postnatal periods. IL-12 responses were also compared according to atopic risk and atopic outcomes (doctor-diagnosed asthma, eczema, food allergies and sensitization as evidenced by skin prick testing) at 6 years clinical follow-up. RESULTS: Maternal peripheral blood mononuclear cells (PBMC) synthesized significantly greater amounts of IL-12 than neonatal PBMC, though within maternal-infant pairs IL-12 responses were significantly correlated (r = 0.4, P = 0.019). Moreover, neonatal IL-12 responses were positively correlated with neonatal allergen proliferation for HDM (r = 0.6, P < 0.0001), OVA (r = 0.55, P < 0.0001), cat (r = 0.5, P = 0.003) and BLG (r = 0.55, P = 0.001), but negatively correlated with neonatal IL-13 responses to both allergens tested (HDM: r = - 0.4, P = 0.03 and OVA: r = - 0.5, P = 0.001). Both neonatal and maternal IL-12 responses were positively correlated with postnatal IFN-gamma responses to HDM at 12, 18 and 24 months of age (responses after age of 2 years were not assessed). There was no relationship between atopic risk and IL-12 capacity in the neonatal period, but there was a (non-significant) trend for neonatal IL-12 responses to be lower in the high-risk children who developed clinical allergy at 6 years (compared with the low risk group) although the number in this analysis was small. CONCLUSIONS: Reduced APC IL-12 production in the perinatal period was associated with reduced T cell activation (lymphoproliferation), stronger neonatal Th2 responses, and weaker Th1 responses to allergen in the postnatal period. This supports the notion that variations in APC function in early life may contribute to altered allergen-specific cytokine responses associated with later allergy.

Allergens↗
PubMed2003

Aluminium administration is associated with enhanced hepatic oxidant stress that may be offset by dietary vitamin E in the rat.

It has been proposed that aluminium toxicity may be mediated, at least in part, by free radical generation. We have investigated the effects of aluminium lactate administration on indices of hepatic oxidant stress, and the consequences of concomitant dietary vitamin E, in male albino Wistar rats. Aluminium lactate was administered for 4 weeks, by ip injection at 10 mg aluminium/kg body weight. Groups of animals received a chow diet containing 0, 5, 15, or 20 mg vitamin E/g of food. A control group of rats received a normal chow diet, without being injected with aluminium. The rats were killed after 4 weeks, and blood and liver tissue removed for the measurement of aluminium and markers of oxidative stress. Plasma and liver aluminium levels were increased in all groups of animals receiving aluminium lactate (P < 0.01), although these levels were significantly reduced in rats receiving concomitant vitamin E (P < 0.05). Aluminium treatment was associated with significantly increased levels of hepatic reactive oxygen species (ROS) (P < 0.01) that were attenuated by concomitant vitamin E (P < 0.05). Hepatic catalase and reduced glutathione levels were both reduced in animals treated with aluminium (P < 0.05).

Aluminum Compounds↗
PubMed2003

Bacterial contamination of surgical gloves by water droplets spilt after scrubbing.

Wound infection and deep sepsis can have disastrous consequences, particularly in orthopaedic surgery. Strict protocols, ultra-clean air, prophylactic antibiotics, and impervious gowns and drapes, have all been shown to diminish wound infection. However it remains a common and significant problem. The water droplets spilt from the surgeons hands after meticulous scrubbing with povidone iodine were cultured. The permeability of the surgical glove packaging to Gram-positive bacteria was also investigated. The water droplets from the surgeon's arms contained environmental and potentially pathogenic bacteria including a micrococcus, a coliform and coagulase-negative staphylococci. The paper packaging for the range of sterile surgical gloves tested was discovered to be permeable to Gram-positive bacteria. In conclusion accidental water droplet contamination of surgical gloves is a potential source of infection. Alternative recommendations are made.

Equipment Contamination↗
PubMed2003

Poor response to ovulation induction is a stronger predictor of early menopause than elevated basal FSH: a life table analysis.

BACKGROUND: During the course of assisted reproduction treatment, a number of women exhibit a "poor response" to ovulation induction, or demonstrate an elevated basal FSH level (> or =10 IU/l) at a young age. We sought to determine whether these women are at increased risk of early menopause and poor reproductive performance. METHODS: A retrospective cohort study included 118 "poor responders" with normal basal FSH level (<10 IU/l), 164 women with raised basal FSH (> or =10 IU/l), and 265 controls, who underwent assisted reproduction treatment between 1987 and 1998. All women were < 40 years of age at the time of treatment and had normal menstrual cycles. Participants were sent a postal questionnaire in 2000-2001, seeking information on ovarian function and reproductive performance following cessation of treatment. RESULTS: After adjusting for age and smoking habits, women with poor response and raised basal FSH levels were more likely to experience symptoms of the peri-menopause [hazard ratios 2.4, 95% confidence interval (CI) 1.52-3.78, and 2.76, 95% CI 1.78-4.29 respectively, P = 0.0001]. Poor responders were six times and 23 times more likely to experience the menopause within 10 years of treatment than those with raised basal FSH levels and controls respectively (hazard ratio 5.97 and 23.9, P = 0.015 and 0.002 respectively). Poor responders and those with raised basal FSH levels have half the chance of spontaneous conception after discontinuation of treatment compared with controls (P < 0.007). CONCLUSIONS: Both poor response to ovarian stimulation and raised basal FSH are markers of reduced ovarian reserve and predict an increased risk of early menopause.

Adult↗