Circulating omega-7 fatty acids are differentially related to metabolic dysfunction and incident type II diabetes: The Multi-Ethnic Study of Atherosclerosis (MESA).

AIM: Determine whether plasma omega-7 vaccenic acid and palmitoleic acid levels are related to homeostasis model of insulin resistance scores and incident type II diabetes, and whether race/ethnicity modifies these associations. METHODS: Plasma phospholipid fatty acids were measured by gas chromatography with flame-ionization detection in Multi-Ethnic Study of Atherosclerosis participants. Linear regression determined associations of vaccenic acid and palmitoleic acid with log-transformed homeostasis model of insulin resistance scores (n=5689), and Cox regression determined associations with incident type II diabetes (n=5413, 660 cases). Race-interactions were tested. RESULTS: Adjusting for typical risk factors, higher levels of plasma vaccenic acid were found to be inversely associated with insulin resistance scores across all four race/ethnicities, and a significant race-interaction was observed between Hispanics and Caucasians (P for interaction=0.03). Vaccenic acid was related to 17%, 32%, and 39% lower risks of incident type II diabetes in Black, Hispanic, and Chinese American participants, respectively. Differences in associations between races were detected (P for interactions<0.05). By contrast, higher levels of plasma palmitoleic acid were related to greater insulin resistance scores in Blacks (P<0.001) and Hispanics (P<0.001); significant race-based differences between associations were detected (P for interactions<0.05). Palmitoleic acid was correspondingly related to a 21% greater risk of incident type II diabetes in Black individuals. CONCLUSIONS: Results suggest that plasma vaccenic acid and palmitoleic acid are markers of metabolic health and dysfunction, respectively. Coupled with previous evidence and the significant race-interactions, our findings have implications for future studies of the race-based differences in omega-7 fatty acids and their regulation in the context of deteriorating metabolic health.

Multimodality quantitative assessments of myocardial perfusion using dynamic contrast enhanced magnetic resonance and 15O-labelled water positron emission tomography imaging.

Kinetic modelling of myocardial perfusion imaging data allows the absolute quantification of myocardial blood flow (MBF) and can improve the diagnosis and clinical assessment of coronary artery disease (CAD). Positron emission tomography (PET) imaging is considered the reference standard technique for absolute quantification, whilst oxygen-15 (15O)-water has been extensively implemented for MBF quantification. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has also been used for MBF quantification and showed comparable diagnostic performance against (15O)-water PET studies. We investigated for the first time the diagnostic performance of two different PET MBF analysis softwares PMOD and Carimas, for obstructive CAD detection against invasive clinical standard methods in 20 patients with known or suspected CAD. Fermi and distributed parameter modelling-derived MBF quantification from DCE-MRI was also compared against (15O)-water PET, in a subgroup of 6 patients. The sensitivity and specificity for PMOD was significantly superior for obstructive CAD detection in both per vessel (0.83, 0.90) and per patient (0.86, 0.75) analysis, against Carimas (0.75, 0.65), (0.81, 0.70), respectively. We showed strong, significant correlations between MR and PET MBF quantifications (r=0.83-0.92). However, DP and PMOD analysis demonstrated comparable and higher haemodynamic differences between obstructive versus (no, minor or non)-obstructive CAD, against Fermi and Carimas analysis. Our MR method assessments against the optimum PET reference standard technique for perfusion analysis showed promising results in per segment level and can support further multi-modality assessments in larger patient cohorts. Further MR against PET assessments may help to determine their comparative diagnostic performance for obstructive CAD detection.

CTPA protocol optimisation audit: challenges of dose reduction with maintained image quality.

AIM: To assess computed tomography (CT) pulmonary angiography (CTPA) dose and image quality in a large teaching hospital, and subsequently, to optimise the protocol in order to reduce the dose without affecting image quality. MATERIALS AND METHODS: Dose-length product (DLP), patient size, and objective quality parameters (contrast-to-noise ratio and signal-to-noise ratio on standardised levels) were recorded from 31 patients undergoing CTPA, where also a subjective image quality evaluation was carried out independently by three specialist cardiothoracic consultant radiologists. An equivalent objective and subjective quality assessment was carried out on a cohort of the same size in a different tertiary healthcare centre. Moreover, experimental tests using anthropomorphic chest phantoms were performed, using different scan parameters. In light of the above analysis, two of the scanner settings for CTPA were modified, i.e., the SureExposure pre-set was changed to "Standard" noise level, quantified with standard deviation (SD) of 19, and the minimum amperage setting lowered from 80 to 40 mA. A second cohort of patients using this new protocol was audited, following the same methodology. RESULTS: The average DLP of patients undergoing CTPA was initially found to be higher than both local and national dose reference levels (DRLs; 559 versus 300 mGy·cm and 400 mGy·cm, respectively). The new protocol led to a reduction in average DLP (359 mGy·cm) while the image quality, assessed by three cardiothoracic consultant radiologists, was preserved. CONCLUSION: The CTPA protocol was implemented in the Royal Infirmary of Edinburgh resulting in significant dose reduction, and is now compliant with national and local DRLs. The image quality was maintained.

Feasibility of radiation dose reduction using AIDR-3D in dynamic pulmonary CT perfusion.

AIM: To assess the feasibility of radiation dose reduction with adaptive iterative dose reduction (AIDR-6 3D) reconstruction in dynamic pulmonary CT perfusion. MATERIALS AND METHODS: CTP examinations of 10 patients acquired at 100 kVp/50 mAs were reconstructed with filtered back projection (FBP) and AIDR-3D. Artificial noise was added to raw data (pre-reconstruction projection data) to simulate lower tube current scanning. Radiodensity (in Hounsfield units), noise, and perfusion values were compared. RESULTS: There was no significant difference in noise between the full and simulated reduced tube current with AIDR-3D reconstruction (p = 1). There was significantly lower noise in lung tissue with AIDR-3D images when compared to reconstructions without AIDR-3D (p = 0.005) and no significant change in the radiodensity (p = 1; mean difference <6 HU). Mean perfusion values increased significantly at lower tube currents (25 and 12.5 mAs), compared to 50 mAs (p = 0.005). This effect was significantly greater in larger patients compared to thin patients. CONCLUSION: AIDR-3D produced significantly lower noise images than FBP-based algorithms and maintained consistent noise levels in lung at 12.5 mAs, indicating this algorithm is suitable for reduced dose lung perfusion imaging. Iterative reconstruction allows significant radiation dose reduction of up to fourfold in smaller patients, and up to twofold in the medium/large size patients. The increase in perfusion values at 25% simulated tube currents is attributed to attenuation bias.

Iterative reconstruction and individualized automatic tube current selection reduce radiation dose while maintaining image quality in 320-multidetector computed tomography coronary angiography.

AIM: To assess the effect of two iterative reconstruction algorithms (AIDR and AIDR3D) and individualized automatic tube current selection on radiation dose and image quality in computed tomography coronary angiography (CTCA). MATERIALS AND METHODS: In a single-centre cohort study, 942 patients underwent electrocardiogram-gated CTCA using a 320-multidetector CT system. Images from group 1 (n = 228) were reconstructed with a filtered back projection algorithm (Quantum Denoising Software, QDS+). Iterative reconstruction was used for group 2 (AIDR, n = 379) and group 3 (AIDR3D, n = 335). Tube current was selected based on body mass index (BMI) for groups 1 and 2, and selected automatically based on scout image attenuation for group 3. Subjective image quality was graded on a four-point scale (1 = excellent, 4 = non-diagnostic). RESULTS: There were no differences in age (p = 0.975), body mass index (p = 0.435), or heart rate (p = 0.746) between the groups. Image quality improved with iterative reconstruction and automatic tube current selection [1.3 (95% confidence intervals (CI): 1.2-1.4), 1.2 (1.1-1.2) and 1.1 (1-1.2) respectively; p < 0.001] and radiation dose decreased [274 (260-290), 242 (230-253) and 168 (156-180) mGy cm, respectively; p < 0.001]. CONCLUSION: The application of the latest iterative reconstruction algorithm and individualized automatic tube current selection can substantially reduce radiation dose whilst improving image quality in CTCA.

Chevalier Jackson: pioneer and protector of children.

Chevalier Jackson was one of the greatest pioneers of otolaryngology. He was a pioneer of oesophagoscopy, bronchoscopy and the removal of foreign bodies. He changed the mortality rate for an airway foreign body from 98 per cent to a survival rate of 98 per cent. He became distressed by the number of preventable injuries in children from the ingestion of caustic substances, most commonly household lye. His experiences of children with oesophageal stricturing secondary to caustic ingestion moved him to start a campaign to force manufacturers to label all poisonous substances as such. This took him from the American Senate to the House of Representatives and back again; the Federal Caustic Poisons Act (1927) is still enforced today. In a career with over 400 publications, written during exacerbations of his pulmonary tuberculosis, his life story is a remarkable one, only part of which is widely known.

Cardiac and coronary CT comprehensive imaging approach in the assessment of coronary heart disease.

Cardiac CT is a rapidly advancing technology. Non-invasive CT coronary angiography is an established technique for assessing coronary heart disease with accuracy similar to invasive coronary angiography. CT myocardial perfusion imaging can now identify perfusion defects in animal models and humans. MRI is the current 'gold standard' for the assessment of myocardial viability, but it is now also possible to assess delayed enhancement by CT. This has led to the possibility of a 'one-stop shop' for cardiovascular imaging that would provide information on anatomy, function, perfusion and viability in one rapid diagnostic test at a radiation dose equivalent to contemporary nuclear medicine imaging. This review discusses the current status of 'one-stop shop' cardiac CT assessment, clinical utility and directions for future research.

The workload of stroke thrombolysis: a prospective study in a district general hospital setting.

Many hospitals are still setting up acute stroke thrombolysis services, often delayed by fears over workload. However, there are few data on how many patients require urgent assessment before one is treated. We prospectively studied all referrals to the 24-hour stroke thrombolysis service, February 2009 - January 2010, in Southampton General Hospital. 128 patients were referred to the thrombolysis team and 20 received thrombolysis. The most common reasons for treatment exclusion were: stroke severity (37%), time from onset (26%) or CT findings (15%). Approximately six patients required urgent assessment by the thrombolysis team for every one treated. These data are crucial to inform service planning.

Diagnostic otoscopy skills of community ear assistants in Western Nepal.

INTRODUCTION: Deafness is a major problem in developing countries. Rural communities tend to be affected more than urban ones, and chronic otitis media is common. The World Health Organization has proposed primary ear care as a method of providing otological services in developing countries. This study aimed to assess the diagnostic otoscopy skills of community ear assistants in rural Western Nepal. MATERIALS AND METHODS: Community ear assistants undertook the pre-operative evaluation of 92 patients selected for middle-ear surgery in an 'ear camp' setting. The otoscopy skills of community ear assistants were also assessed by means of an otoscopy quiz. Consultant otologists and trainee otolaryngologists underwent an identical assessment. RESULTS: The community ear assistants' selection of patients for middle-ear surgery concurred with the consultant otologists' opinion in 87 of 92 patients (94.5 per cent). The level of community ear assistants' otoscopy skills was between that of junior and senior otolaryngology trainees. CONCLUSIONS: With intensive training, medically unqualified community ear assistants can develop otoscopy skills comparable to those of medically qualified otolaryngology trainees. These results support the development of primary ear care in poorer countries where access to specialist otological services is difficult or impossible.

History of parathyroid gland surgery: an historical case series.

The history of the parathyroid glands is a fascinating one full of famous medical names. The discovery of the glands was followed by laborious research into their anatomy, embryology and pathology and into the physiology of calcium metabolism; this led to the manufacture of hormone substitutes and, finally, to the refinement of surgical techniques. The glands were first identified in 1850 by Sir Richard Owen, conservator of the Hunterian Museum, but it was not until 1880 that the term 'glandulae parathyroideae' was first used. The physiology of parathyroid hormone and calcium metabolism eluded physicians and the forefathers of thyroid surgery alike for several decades more. Patients were treated as curiosities and were documented as untreatable medical patients or as inexplicable thyroid surgery complications. Halsted noticed the 'disastrous results from the loss of the glands' and the resulting tetany, as did Billroth. It is the patients, however, who best illustrate the journey of discovery. In this review, we discuss three cases, highlighting their contributions.

An update on cardioembolic stroke.

About one-fifth of all ischaemic strokes are cardioembolic. Recent years have seen considerable progress in our understanding of atrial fibrillation, the most important cause of cardioembolism, and evidence-based treatment strategies have emerged. Progress in relation to other cardioembolic disorders has been more limited and here stroke prevention strategies remain less certain and subject to debate. This article briefly reviews the methods currently used to identify and investigate cardioembolic stroke and then provides an update on stroke prevention in relation to atrial fibrillation, valvular heart disease, patent foramen ovale and left ventricular dysfunction (after myocardial infarction and chronic failure).

Endovascular therapy of symptomatic intracranial stenosis in patients with impaired regional cerebral blood flow or failure of medical therapy.

BACKGROUND AND PURPOSE: Symptomatic intracranial stenoses have a high risk for a recurrent stroke if treated medically. Although angioplasty and stent placement are proposed treatment options, data on longer-term outcome are limited. MATERIALS AND METHODS: We analyzed all endovascular procedures on symptomatic intracranial stenosis at our institution from January 1998 to December 2005. We retrospectively assigned patients to group A (symptoms despite antithrombotic therapy) or group B (impaired regional cerebral blood flow [rCBF]). Primary outcome events were periprocedural major complications or recurrent ischemic strokes in the territory of the treated artery. We used the Kaplan-Meier method to calculate survival probabilities. RESULTS: The procedural technical success rate was 92% (35/38) with periprocedural major complications in 4 cases (10.5%; group A [8.3%, 2/24], group B [14.3%, 2/14]). Median (range) follow-up for the 33 patients with technically successful procedures was 21 (0-72) months. Recurrent ischemic strokes occurred in 15% (3/20) of patients in group A and 0% (0/13) of patients in group B. Overall, there were 21% (7/33) primary outcome events (group A [25%, 5/20], group B [15%, 2/13]). There was a nonsignificant trend for better longer-term survival free of a major complication or recurrent stroke in patients with impaired rCBF compared with patients who were refractory to medical therapy treatment (Kaplan-Meier estimate 0.85 [SE 0.10] vs 0.72 [SE 0.11] at 2 years, respectively). CONCLUSION: Interventional treatment of symptomatic intracranial stenosis carries significant risk for complications and recurrent stroke in high-risk patients. The observation that patients with impaired rCBF may have greater longer-term benefit than medically refractory deserves further study.

History of myringotomy and grommets.

The first recorded myringotomy was in 1649. Astley Cooper presented two papers to the Royal Society in 1801, based on his observation that myringotomy could improve hearing. Widespread inappropriate use of the procedure followed, with no benefit to patients; this led to it falling from favour for many decades. Hermann Schwartze reintroduced myringotomy later in the nineteenth century. It had been realised earlier that the tympanic membrane heals spontaneously, and much experimentation took place in attempting to keep the perforation open. The first described grommet was made of gold foil. Other materials were tried, including Politzer's attempts with rubber. Armstrong's vinyl tube effectively reintroduced grommets into current practice last century. There have been many eponymous variants, but the underlying principle of creating a perforation and maintaining it with a ventilation tube has remained unchanged. Recent studies have cast doubt over the long-term benefits of grommet insertion; is this the end of the third era?

A historical review of head and neck cancer in celebrities.

INTRODUCTION: The illnesses of celebrity patients always receive more attention from the general public than those of ordinary patients. With regard to cancer, this fact has helped to spread information about the four major malignancies: breast cancer, prostatic cancer, lung cancer and colorectal cancer. Head and neck cancer, on the other hand, is still not well recognised by the lay public, although the risk factors are similar to those of lung cancer. It was the objective of this analysis to identify cases of celebrity patients, the description of which could help to increase awareness of head and neck cancer, its symptoms and risk factors. METHODS: The Internet and medical literature databases were searched for celebrity patients who had suffered from head and neck cancer. RESULTS: The search revealed numerous famous head and neck cancer patients. However, only seven cases were documented well in the medical literature. Among the identified persons were one emperor, two United States presidents, a legendary composer, a world-renowned medical doctor, an outstanding athlete and an extraordinary entertainer. In spite of their exclusive position in society, these patients did not have a better prognosis compared with ordinary patients of their time. Only two of the group experienced long term survival and only one was cured. None of these influential figures used their influence to fund research or to promote knowledge about their respective diseases. CONCLUSION: The identified cases could help increase public awareness of head and neck cancer. Similar to activities in other oncologic fields, current celebrity head and neck cancer patients should be encouraged to discuss their diseases openly, which could have a positive effect on public health.

A study of the workload and effectiveness of a comprehensive acute stroke service.

OBJECTIVE: To study the workload of and use of acute intervention within an established acute stroke service, the Calgary Stroke Programme (CSP). METHODS: Prospective record of all acute referrals, diagnoses, and management decisions over a 4 month period. RESULTS: The CSP received 572 referrals (median: 32 per week), 88% of which were made between 7 am and midnight. Of the 427 patients seen in person, 29% had not had an acute stroke or transient ischaemic attack (TIA). Fifty percent of patients with suspected acute stroke were referred within 3 h of symptom onset and 11% with acute ischaemic stroke (equating to 35% of those referred within 3 h of onset and seen in person) were treated with thrombolysis. CONCLUSION: Centralisation of services facilitates the rapid referral of, and use of acute interventions in, patients with acute stroke and TIA. Centralised services are likely to be busy (although less so at night), to attract large numbers of patients with disorders that mimic stroke and TIA, and yet still likely to treat only the minority of acute strokes using thrombolysis. These observations may help those planning similar services and underline the need to develop more widely applicable treatments for acute stroke.

Degradation of poly-L-lactide. Part 1: in vitro and in vivo physiological temperature degradation.

Poly-L-lactide (PLLA) is one of the most significant members of a group of polymers regarded as bioresorbable. The degradation of PLLA proceeds through hydrolysis of the ester linkage in the polymer's backbone and is influenced by the polymer's initial molecular weight and degree of crystallinity. To evaluate its degradation PLLA pellets were processed by compression moulding into tensile test specimens and by extrusion into 2 mm diameter lengths of rod, prior to being sterilized by ethylene oxide gas (EtO) and degraded in both in vitro and in vivo environments. On retrieval at predetermined time intervals, procedures were used to evaluate the material's molecular weight, crystallinity, mechanical strength, and thermal properties. Additionally, the in vivo host tissue's biological response was analysed. The results from this study suggest that in both the in vitro and in vivo environments, degradation proceeded at the same rate and followed the general sequence of aliphatic polyester degradation, ruling out enzymes contributing and accelerating the degradation rate in vivo. Additionally, the absence of cells marking an inflammatory response suggests that the PLLA rods investigated in vivo were biocompatible throughout the 44 weeks duration of the study, before any mass loss was observed.

Degradation of poly-L-lactide. Part 2: increased temperature accelerated degradation.

Poly-L-lactide (PLLA) is one of the most significant members of a group of polymers regarded as bioresorbable. The degradation of PLLA proceeds through hydrolysis of the ester linkages in the polymer's backbone; however, the time for the complete resorption of orthopaedic devices manufactured from PLLA is known to be in excess of five years in a normal physiological environment. To evaluate the degradation of PLLA in an accelerated time period, PLLA pellets were processed by compression moulding into tensile test specimens, prior to being sterilized by ethylene oxide gas (EtO) and degraded in a phosphate-buffered solution (PBS) at both 50 degrees C and 70 degrees C. On retrieval, at predetermined time intervals, procedures were used to evaluate the material's molecular weight, crystallinity, mechanical strength, and thermal properties. The results from this study suggest that at both 50 degrees C and 70 degrees C, degradation proceeds by a very similar mechanism to that observed at 37 degrees C in vitro and in vivo. The degradation models developed also confirmed the dependence of mass loss, melting temperature, and glass transition temperature (Tg) on the polymer's molecular weight throughout degradation. Although increased temperature appears to be a suitable method for accelerating the degradation of PLLA, relative to its physiological degradation rate, concerns still remain over the validity of testing above the polymer's Tg and the significance of autocatalysis at increased temperatures.