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Biomedical subjects

D Williams

Publications and source records attributed to D Williams.

At least 37 records · Page 2Linked to original sources
PubMed2005

A comparison of computerised strain gauge plethysmography with D-dimer testing in screening for deep-vein thrombosis.

There has been a significant increase in the amount of diagnostic testing performed to confirm or refute a diagnosis of deep-vein thrombosis (DVT), often in low-risk patients. D-dimer testing and computer-assisted strain gauge plethysmography (SGP) are rapid, inexpensive methods of excluding DVT and, in combination with a clinical probability score for DVT, both have been used to accurately exclude DVT. D-dimer testing, SGP and a combination of both in excluding DVT were compared in 243 ambulant outpatients who followed a prespecified investigation protocol. The negative-predictive value of D-dimer testing alone was 100%, 93.9% (95% CI 93.6-94.1) and 80% (95% CI 73.7-86.3) in patients with a low, moderate and high pretest probability (PTP) score for DVT respectively. The corresponding results for SGP were 95.6% (95% CI 95.5-95.7), 86.1% (95% CI 85.9-86.4) and 77.8% (95% CI 75.9-79.7) in patients with a low, moderate and high PTP score for DVT respectively. D-dimer testing provided a rapid, cost-effective method for excluding DVT in low-risk ambulant patients, which was superior to SGP. Combined use of the modalities did not improve any aspect of clinical decision making.

Biomarkers↗
PubMed2005

Evidence for inequalities in the management of coronary heart disease in Scotland.

OBJECTIVES: To investigate whether sex, age, and deprivation inequalities existed in the prescription of secondary preventive treatment for coronary heart disease (CHD) in Scottish general practice and whether these differences altered over time. DESIGN: 6 year cross sectional study based on general practice morbidity and prescribing data. SETTING: 55 primary care practices in Scotland. SUBJECTS: 14,435 patients with diagnosed CHD. MAIN OUTCOME MEASURE: Prescription of various groups of secondary preventive treatment in six study years. RESULTS: The use of all secondary prevention treatments increased over time (63.6% of patients with CHD in 1997 to 87.6% in 2002). After adjustments for age, sex, deprivation, co-morbidities, and practice where appropriate, women received fewer secondary prevention treatments than men, a difference that increased over time (March 1997: adjusted odds ratio (OR) 0.9, 95% confidence interval (CI) 0.8 to 1.0; March 2002: OR 0.6, 95% CI 0.6 to 0.7). Sex differences were observed within each group of treatments studied. The oldest group of patients was less likely than the youngest group to receive any secondary preventive treatment in the year up to March 1997 (OR 0.6, 95% CI 0.5 to 0.7) but were more likely by 2002 (OR 1.3, 95% CI 1.1 to 1.5) to receive secondary prevention. The most affluent patients with CHD were significantly less likely to receive a statin between March 1998 and 2001 (March 1998 OR 0.6, 95% CI 0.5 to 0.9), a finding that disappeared by 2002 (OR 0.9, 95% CI 0.7 to 1.1). CONCLUSION: The results suggest that inequalities exist in the secondary prevention of CHD in Scotland.

Adrenergic beta-Antagonists↗
PubMed2005

Forward surgery on Operation Telic--Iraq 2003.

Two Air Assault Surgical Groups (AASGs) from 16 Close Support Medical Regiment deployed to Kuwait on Operation Telic in February 2003. Each AASG was comprised of a four-table resuscitation facility, a two table FST and a twin-bedded ITU facility. An A+E Consultant and nurse, an experienced radiographer and laboratory technician with two further RGNs and CMTs provided resuscitation support. Each FST had an orthopaedic and a general surgeon, two anaesthetists and eight operating department practitioners. Further equipment consisted of a Polymobil 111 X-ray unit, a Sonosite 180 ultrasound scanner and an ISTAT gas, haematocrit and electrolyte analyser. 100 units of mixed blood were carried by each AASG. Fifty-one surgical procedures were performed on thirty one patients. Twenty one of these patients were Iraqi prisoners of war or civilians. Seventeen wound debridements, five amputations, five laparotomies, four insertions of Denham pins with Thomas splintage for femoral fracture, three external fixations and one axillary artery repair formed the basis of the major cases undertaken. The first field use of activated factor VII by the British Army was successful in the resuscitation of a patient with exsanguinating haemorrhage after an open-book (APC-III) pelvic fracture and a ruptured intrapelvic haematoma. The other cases included eleven manipulations under anaesthetic/application of plaster and four finger terminalisations. Forward military surgery has a continued role to play on the modern fast moving battlefield. 16 Close Support Medical Regiment normally supports 16 Air Assault Brigade with its remit for expeditionary operations and SF support. Its experience on Op Telic should influence planning for future deployment.

Adolescent↗
PubMed2005

Timing of aspirin and secondary preventative therapies in acute stroke: support for use of stroke units.

BACKGROUND: We aimed to study the timing of aspirin prescription in ischaemic stroke comparing patients admitted to an acute stroke unit (ASU) directly or via a general medical ward. We also analysed prescription of secondary preventive therapies in stroke patients in an ASU. METHODS: Retrospective analysis was made of medical notes and prescription records of 69 patients admitted to an ASU over a three month period to establish timing of aspirin prescription with respect to onset of stroke symptoms, CT brain scan and route of admission to the ASU. RESULTS: CT brain scans were obtained at a median of 2.1 days post stroke (IQ range 1.3-4.3). Patients directly admitted to the ASU received aspirin earlier post admission compared to those admitted via a medical ward (0.7 vs 2.2 days, p < 0.01) and were also more likely to receive aspirin prior to CT scan being performed (57% vs 19%, p = 0.02). 86% of stroke patients were discharged on an antiplatelet therapy, 79% on a statin, 37% on a thiazide diuretic and 32% on an ACE inhibitor or angiotensin II antagonist. CONCLUSION: Aspirin was given more promptly in acute stroke and more commonly prior to CT scanning in an ASU compared to a medical ward. Statin therapy is used extensively in stroke but there is a much lower rate of initiation of other secondary preventive therapies (e.g. anti-hypertensive therapy) in hospital. These findings demonstrate a hesitancy in early use of aspirin amongst general physicians and lends support for the use of stroke units.

Aged↗
PubMed2005

HIV and syphilis in young Chinese adults: implications for spread.

Our objective was to explore the epidemiology of HIV and syphilis at population level in young Chinese adults. The study was carried out in six areas of three Chinese provinces: Zhejiang, Yunnan and Shaanxi. All couples attending the compulsory premarital examination were recruited. Routinely taken blood was collected onto filter paper. Tests for HIV and syphilis used modified particle agglutination techniques. In all, 17,226 individuals were tested. There were no HIV infections in Zhejiang or Shaanxi. In Yunnan, there were 28 positives: 0.75% (95% confidence interval: 0.5, 1.1), with 22 (78%) in men and 16 (57%) in known high-risk individuals. Syphilis prevalence ranged from 0.33% to 0.71% across study sites, with 58% in men. Although syphilis levels suggest that unsafe sexual activity is occurring in all areas, HIV is not yet affecting the general population of Zhejiang or Shaanxi. The epidemic in Yunnan is being driven by injecting drug users, but there may now be transmission in the general population.

Adult↗
PubMed2004

Solar wind-induced atmospheric erosion at Mars: first results from ASPERA-3 on Mars Express.

The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on board the Mars Express spacecraft found that solar wind plasma and accelerated ionospheric ions may be observed all the way down to the Mars Express pericenter of 270 kilometers above the dayside planetary surface. This is very deep in the ionosphere, implying direct exposure of the martian topside atmosphere to solar wind plasma forcing. The low-altitude penetration of solar wind plasma and the energization of ionospheric plasma may be due to solar wind irregularities or perturbations, to magnetic anomalies at Mars, or both.

Journal Article↗
PubMed2004

Experimental limit on the cosmic diffuse ultrahigh energy neutrino flux.

We report results from 120 h of live time with the Goldstone lunar ultrahigh energy neutrino experiment (GLUE). The experiment searches for < or = 10 ns microwave pulses from the lunar regolith, appearing in coincidence at two large radio telescopes separated by 22 km and linked by optical fiber. Such pulses would arise from subsurface electromagnetic cascades induced by interactions of > or = 100 EeV (1 EeV = 10(18) eV neutrinos in the lunar regolith. No candidates are yet seen, and the implied limits constrain several current models for ultrahigh energy neutrino fluxes.

Journal Article↗
PubMed2004

Initial uptake and evidence of safe prescribing practice with Buproprion (Zyban).

PURPOSE: To study the effect of safety concerns and the introduction of freely available nicotine replacement therapy (NRT) on the prescribing of Buproprion within the General Medical Services (GMS) scheme in Ireland. METHODS: Using the state-supported GMS prescription database in Ireland, we identified 8166 patients who were prescribed Buproprion and 18,450 patients who were prescribed NRT over a 12-month-period. RESULTS: A decline in the prescribing of Buproprion was noted which coincided with concerns regarding the safety of the drug but which preceded the introduction of NRT to the GMS. Furthermore, patients who were prescribed Buproprion were less likely to be co-prescribed potentially interacting drugs (odds ratio (OR): 0.48, 95% confidence intervals (CI): 0.42, 0.54) or drugs known to reduce seizure threshold (OR: 0.63, 95% CI: 0.6, 0.67) indicating good prescribing practice. Patients aged 65 years or more were less likely to be prescribed any form of smoking cessation therapy compared with those aged <65 years (OR: 0.23, 95% CI: 0.22-0.24) indicating that such therapy was targeted at those most likely to benefit. CONCLUSIONS: We provide evidence that prescribers exercised caution in the prescription of Buproprion and were likely to have been influenced both by the safety concerns and the introduction of freely available NRT to the GMS population.

Adolescent↗
PubMed2004

Reduced neurocognition in children who snore.

Obstructive sleep apnea syndrome (OSAS) has been associated with reduced neurocognitive performance in children, but the underlying etiology is unclear. The aim of this study was to evaluate the relationship between hypoxemia, respiratory arousals, and neurocognitive performance in snoring children referred for adenotonsillectomy. Thirteen snoring children who were referred for evaluation regarding the need for adenotonsillectomy to a children's hospital otolaryngology/respiratory department underwent detailed neurocognitive and polysomnographic (PSG) evaluation. PSGs were evaluated for respiratory abnormalities and compared with 13 nonsnoring control children of similar age who were studied in the same manner. The snoring children had an obstructive respiratory disturbance index within normal range (mean obstructive apnea/hypopnea index, 0.6/hr). Despite this, several domains of neurocognitive function were reduced in the snoring group. These included mean verbal IQ scores (snorers 92.6 vs. nonsnorers 110.2, P < 0.001), mean global IQ scores (snorers 96.7 vs. nonsnorers 110.2, P < 0.005), mean selective attention scores (snorers 46.4 vs. nonsnorers 11.8, P < 0.001), mean sustained attention scores (snorers 8.0 vs. nonsnorers 2.2, P = 0.001), and mean memory index (snorers 95.2 vs. nonsnorers 112.1, P = 0.001). There was a direct relationship between number of mild oxygen desaturations of > or = 3%, obstructive hypopneas with > or = 3% oxygen desaturations, and respiratory arousals and severity of neurocognitive deficits, with the greatest effect being on memory scores. The disruption of sleep in snoring children produced by relatively mild changes in oxygen saturation or by increases in respiratory arousals may have a greater effect on neurocognitive function than hitherto appreciated. A possible explanation for these neurocognitive deficits may be the combination of the chronicity of sleep disruption secondary to snoring which is occurring at a time of rapid neurological development in the first decade of life. Future studies need to confirm the reversal of these relatively mild neurocognitive decrements post adenotonsillectomy.

Analysis of Variance↗
PubMed2004

Pethidine and skin warming to prevent shivering during endovascular cooling.

We tested the efficacy of pethidine and cutaneous warming to prevent shivering during percutaneous cooling in unanaesthetized patients. Ten patients scheduled for cranial neurosurgery received pethidine infusion and skin warming. The Setpoint internal heat-exchanging catheter was inserted and cooling to 33.5 degrees C was started. Clonidine and chlorpromazine were given as "rescue medication" to treat shivering. General anaesthesia was planned to be induced after cooling was complete. Rewarming was initiated at dural closure. Three patients successfully completed the protocol, cooling to 33.8 degrees C at a median rate of 3.6 (range: 3.4-3.8) degrees C/h. Two patients cooled to 33.8 degrees C but required treatment for shivering (cooling rate: 2.9 [2.8-3.1] degrees C/h). Four patients failed to cool adequately because of refractory shivering (cooling rate: 20 [1.5-2.9] degrees C/h). One patient did not shiver and yet failed to cool adequately (cooling rate: 0.76 degrees C/h). Rewarming was at a rate of 26 (1.2-4.3) degrees C/h. There were no significant complications arising from catheter placement. The combination of skin warming and pethidine was not reliable enough to be recommended for use during endovascular cooling in unanaesthetized patients.

Adult↗
PubMed2003

Influence of material deprivation on prescribing patterns within a deprived population.

OBJECTIVE: To study the effect of material deprivation on prescribing trends in primary care, using a locally derived deprivation score. METHODS: A retrospective analysis of prescribing trends linked to material deprivation by district electoral division (DED) in the Eastern Region of the General Medical Services in Ireland (population of 334,031) was performed. Standardised prescribing ratios were determined for a number of drug classes, including those that could be used to identify particular diseases for 181,647 patients who were assigned a locally derived material deprivation score. RESULTS: Prescribing rates for a number of medications including anti-asthma, nitrate and benzodiazepine medications increased, whilst the prescribing of other medications such as anti-parkinsonian and antidepressive agents decreased with increasing deprivation. CONCLUSIONS: Our results suggest that, even within a population considered to be economically deprived, different levels of deprivation may significantly influence general practitioner prescribing patterns. Within the group of centrally active medications, the prescription of symptomatic medications increased with increasing material deprivation, whilst the prescription of disease-specific medications decreased with increasing material deprivation.

Cultural Deprivation↗
PubMed2003

Under-prescribing of cardiovascular therapies for diabetes in primary care.

OBJECTIVE: To determine the extent to which cardiovascular therapies are prescribed in primary care for those with diabetes, compared with those without diabetes. METHODS: Population study of patients with and without diabetes identified using a national primary care prescribing database. All patients receiving a prescription for any diabetes therapy, including insulin and oral hypoglycaemic drugs, or diagnostic test kit for glucose ( n=8523) and those receiving no such therapies ( n=145,756) during a 1-year period (September 1999-August 2000) in the Eastern Regional Health Authority of Ireland were identified. In addition, a sub-set of patients receiving a nitrate prescription, a marker for ischaemic heart disease (IHD), were also identified ( n=14,826). Odds ratios and 95% confidence intervals for prescribing of cardiovascular therapies between those with diabetes and those without, adjusted for age and gender, were calculated using logistic regression. RESULTS: The proportion of those (and 95% CES) with diabetes and IHD prescribed secondary preventative therapies was 37.3% (35.0, 39.6) for statins, 55.3% (53.0, 57.6) for angiotension converting enzyme inhibitors, 34.7% (32.5, 36.9) for beta blockers, 73.3% (71.2, 75.4) for aspirin, 4.4% (3.4, 5.4) for angiotensin-II antagonists and 2.5% (1.8, 3.2) for fibrates. The adjusted odds ratios for prescribing in those with diabetes compared with those without are 1.44 (1.30, 1.61) for statins, 3.09 (2.79, 3.42) for angiotension converting enzyme inhibitors, 0.82 (0.74, 0.91) for beta blockers, 1.23 (1.09, 1.38) for aspirin, 1.47 (1.13, 1.87) for angiotensin-II receptor blockers and 4.23 (2.88, 6.14) for lipid-lowering fibrates. CONCLUSION: The greater rate of prescribing of cardiovascular therapies in those with diabetes relative to those without is not unexpected given the higher risk of coronary heart disease in those with diabetes. However, the proportion of patients with diabetes, particularly those with established IHD, prescribed cardiovascular therapies is considerably below that recommended in local and international guidelines.

Adrenergic beta-Antagonists↗
PubMed2003

A comprehensive study of gray matter loss in patients with Alzheimer's disease using optimized voxel-based morphometry.

Voxel-based morphometry (VBM) has already been applied to MRI scans of patients with Alzheimer's disease (AD). The results of these studies demonstrated atrophy of the hippocampus, temporal pole, and insula, but did not describe any global brain changes or atrophy of deep cerebral structures. We propose an optimized VBM method, which accounts for these shortcomings. Additional processing steps are incorporated in the method, to ensure that the whole spectrum of brain atrophy is visualized. A local group template was created to avoid registration bias, morphological opening was performed to eliminate cerebrospinal fluid voxel misclassifications, and volume preserving modulation was used to correct for local volume changes. Group differences were assessed and thresholded at P < 0.05 (corrected). Our results confirm earlier findings, but additionally we demonstrate global cortical atrophy with sparing of the sensorimotor cortex, occipital poles, and cerebellum. Moreover, we show atrophy of the caudate head nuclei and medial thalami. Our findings are in full agreement with the established neuropathological descriptions, offering a comprehensive view of atrophy patterns in AD.

Aged↗
PubMed2003

Prescription monitoring in an Irish hospital.

The prescribing of medicines is an integral part of the provision of healthcare and represents a relatively safe, effective and inexpensive mode of treatment. Hospital prescribing is of importance not alone for patients but also for the impact that it has on the prescribing of drugs in the community. We conducted a 'snap-shot' study of 1,488 hospital prescriptions and assessed such areas as legibility, generic prescribing and drug dosage. The average number of active prescriptions per patient was 5.47 for medical in-patients and 5.05 for surgical in-patients. 5% of prescriptions were deemed illegible and the rate of generic prescribing was relatively low. However the rate of compliance with the hospital formulary was good. The spectrum of drugs prescribed changed significantly from a previous study performed in 1987. Continuous review of doctors' prescribing habits will ensure the safe and economic use of medications.

Drug Prescriptions↗
PubMed2003

Provision of anaesthesia for porcine cardiac transplantation at the veterinary school in Trinidad and Tobago.

A successful heterotopic cardiac transplantation was performed between sibling female Yorkshire Juvenile swine. Adequate pre-medication with azaperone and a smooth induction were ensured for both pigs, which were anaesthetized simultaneously with sodium thiopentone followed by endotracheal intubation and intermittent positive pressure ventilation. Inhalation anaesthetic agents were used for maintenance, neuromuscular blockade was achieved with cisatracurium and both fentanyl and tramadol were used to provide analgesia. Invasive monitoring was used in both the donor and recipient. Central venous pressure (CVP) was maintained at > 10 cm H2O and mean arterial pressure (MAP) > 60 mmHg. Heparin was injected during the surgical dissection of the heart in the donor to prevent coronary thrombosis and prior to aortic side clamping for end-to-side anastomosis of the donor heart in the recipient abdomen. After transplantation, the cardiovascular parameters of the recipient showed a MAP of 85-105 mmHg and a CVP of 8-10 cm H2O while echocardiography of the transplanted heart confirmed an ejection fraction (EF) of 80%. A functional anaesthetic team was assembled and trained to provide anaesthesia for porcine cardiac transplantation. The transplanted heart suffered pump failure after 69 days and was excised for performance of tissue analysis.

Anesthesia, General↗
PubMed2002

Exposure to power frequency electric fields and the risk of childhood cancer in the UK.

The United Kingdom Childhood Cancer Study, a population-based case-control study covering the whole of Great Britain, incorporated a pilot study measuring electric fields. Measurements were made in the homes of 473 children who were diagnosed with a malignant neoplasm between 1992 and 1996 and who were aged 0-14 at diagnosis, together with 453 controls matched on age, sex and geographical location. Exposure assessments comprised resultant spot measurements in the child's bedroom and the family living-room. Temporal stability of bedroom fields was investigated through continuous logging of the 48-h vertical component at the child's bedside supported by repeat spot measurements. The principal exposure metric used was the mean of the pillow and bed centre measurements. For the 273 cases and 276 controls with fully validated measures, comparing those with a measured electric field exposure >/=20 V m(-1) to those in a reference category of exposure <10 V m(-1), odds ratios of 1.31 (95% confidence interval 0.68-2.54) for acute lymphoblastic leukaemia, 1.32 (95% confidence interval 0.73-2.39) for total leukaemia, 2.12 (95% confidence interval 0.78-5.78) for central nervous system cancers and 1.26 (95% confidence interval 0.77-2.07) for all malignancies were obtained. When considering the 426 cases and 419 controls with no invalid measures, the corresponding odds ratios were 0.86 (95% confidence interval 0.49-1.51) for acute lymphoblastic leukaemia, 0.93 (95% confidence interval 0.56-1.54) for total leukaemia, 1.43 (95% confidence interval 0.68-3.02) for central nervous system cancers and 0.90 (95% confidence interval 0.59-1.35) for all malignancies. With exposure modelled as a continuous variable, odds ratios for an increase in the principal metric of 10 V m(-1) were close to unity for all disease categories, never differing significantly from one.

Adolescent↗