Pyrosequencing-based methods reveal marked inter-individual differences in oncogene mutation burden in human colorectal tumours

Background:

The epidermal growth factor receptor-targeted monoclonal antibody cetuximab (Erbitux) was recently introduced for the treatment of metastatic colorectal cancer. Treatment response is dependent on Kirsten-Ras (K-Ras) mutation status, in which the majority of patients with tumour-specific K-Ras mutations fail to respond to treatment. Mutations in the oncogenes B-Raf and PIK3CA (phosphoinositide-3-kinase) may also influence cetuximab response, highlighting the need for a sensitive, accurate and quantitative assessment of tumour mutation burden.

Methods:

Mutations in K-Ras, B-Raf and PIK3CA were identified by both dideoxy and quantitative pyrosequencing-based methods in a cohort of unselected colorectal tumours (n=102), and pyrosequencing-based mutation calls correlated with various clinico-pathological parameters.

Results:

The use of quantitative pyrosequencing-based methods allowed us to report a 13.7% increase in mutation burden, and to identify low-frequency (<30% mutation burden) mutations not routinely detected by dideoxy sequencing. K-Ras and B-Raf mutations were mutually exclusive and independently associated with a more advanced tumour phenotype.

Conclusion:

Pyrosequencing-based methods facilitate the identification of low-frequency tumour mutations and allow more accurate assessment of tumour mutation burden. Quantitative assessment of mutation burden may permit a more detailed evaluation of the role of specific tumour mutations in the pathogenesis and progression of colorectal cancer and may improve future patient selection for targeted drug therapies.

Nodal presentation of seminoma

We report a 38 year old male with metastatic seminoma in an inguinal lymph node and regression of the primary testis tumour with a past history of orchiopexy--an extremely rare occurrence.

Sleep locus of control and computerized cognitive-behavioral therapy (cCBT)

This study investigated the relationship between sleep locus of control and sleep in a secondary data analysis. Participants were 100 adults with chronic insomnia previously involved in a randomized controlled trial of 5 weeks of computerized cognitive-behavioral therapy (cCBT). Additionally, a sample of 46 completers of an in-person group for insomnia were utilized as a comparison group. At pre-treatment, participants completed the Sleep Locus of Control Scale, the Insomnia Severity Index, the Pre-Sleep Arousal Scale, 7 days of sleep diaries, and participated in structured interviews to assess for psychiatric and medical conditions. Measures were re-administered at post-treatment and at a 4 week follow-up. Results showed that sleep locus of control mediated the impact of cCBT on insomnia severity at follow-up. cCBT more than waiting list control or a convenience sample of individuals treated with in-person CBT, enhanced an internal sleep locus of control. Implications are that sleep locus of control may be an important variable to assess in the internet context and that internet programs for insomnia may want to consider amplifying or giving priority to interventions which enhance an internal sleep locus.

Renal trauma in the west of Ireland--a regional review

There is a paucity of data regarding renal trauma. The majority of cases of renal trauma are amenable to conservative management. We sought to streamline the management of renal trauma in the west of Ireland. Patients presenting with a computerised tomogram–confirmed renal injury were assessed over 5 years. Patient demographics, injury details, initial emergency department management, definitive management, and follow-up were assessed. Renal trauma was graded in a blind fashion (I-V). Twenty-five patients were identified; male:female (23:2). The mean age was 26 years. The majority of renal traumas were managed conservatively (92%); 8% patients underwent nephrectomy. The common mechanisms of renal injuries were road traffic accidents (44%). The majority of cases of renal injuries occur as a result of blunt trauma and can be conservatively treated. Two nephrectomies (8%) were performed. We believe this study potentially can be beneficial as part of an all-Ireland trauma database to improve patient outcome.

Teachers' reporting of suspected child abuse and neglect: behaviour and determinants

By reporting suspected child abuse and neglect, teachers can make an important contribution to the early detection and prevention of abuse. However, teachers are sometimes reluctant to report their suspicions. This study investigated the determinants of teachers' reporting behaviour using concepts from the Integrated Change Model. Self-report data were collected from 296 teachers employed in 15 Australian schools. Compared to their colleagues, teachers who had never suspected child abuse or neglect (non-detectors, N=57, 19%) were more likely to have a lower confidence in their skills for recognising the signs of abuse, a higher degree of perceived social support regarding reporting, less years teaching experience and lower academic qualifications. Among those who had suspected cases of child abuse or neglect (N=239, 81%), teachers who always reported their suspicions (consistent reporters, 82%) were more likely to have firm action plans about reporting and detecting signs of CAN than teachers who did not always report their suspicions (inconsistent reporters, 18%). While only a small proportion of the variance in detection and reporting status was explained, the results illustrate the utility of health promotion theory and methods for improving our understanding of these behaviours.

Biochemical markers may identify preterm infants with a patent ductus arteriosus at high risk of death or severe intraventricular haemorrhage

BACKGROUND

A patent ductus arteriosus (PDA) in preterm infants is associated with increased risk of intraventricular haemorrhage (IVH) and death. Cardiac troponin T (cTnT) and N-terminal-pro-B type natriuretic peptide (NTpBNP) are markers of cardiac function and can predict poor outcome in adults.

AIMS

To determine whether echocardiography and cTnT/NTpBNP levels at 48 h predict death before discharge or severe IVH in preterm infants with a PDA.

METHODS

Infants born <32 weeks' gestation or <1500 g underwent echocardiographic and cTnT/NTpBNP measurements at 12 and 48 h of life. Infants were divided according to their status at discharge: a closed PDA at 48 h, infants with a PDA at 48 h and IVH III/IV and/or death, and infants with a PDA at 48 h without IVH III/IV or death.

RESULTS

Eighty infants with a median gestation of 28 weeks (IQR 26.1-29.5) and birth weight 1.06 kg (0.8-1.21) were included. At 48 h, infants with a PDA and IVH III/IV and/or death had significantly higher median cTnT/NTpBNP levels compared to infants with a PDA without IVH III/IV and/or death and those with spontaneous PDA closure (NTpBNP 9282, 5121 and 740 pmol/l, respectively, p = 0.008, and cTnT 0.66, 0.25 and 0.13 microg/l, respectively, p = 0.027). There were no differences in echocardiographic parameters of PDA size, left atrial to aortic ratio (LA:Ao), left and right ventricular outputs between the PDA groups.

CONCLUSIONS

NTpBNP and cTnT in conjunction with echocardiography may provide a basis for trials of targeted medical treatment in infants with a PDA.

A retrospective study of the clinical experience of the implantable loop recorder in a paediatric setting

The implantable loop recorder (ILR) has proved highly efficacious in the management of syncope, presyncope and palpitations in selected populations. Limited information regarding patient selection and diagnostic yield exists in the paediatric setting. A retrospective evaluation of patients who underwent ILR implantation over a 66-month period, in a tertiary paediatric cardiology unit was conducted. Twenty-three patients (10 male, 13 female) following initial assessment and investigation, were referred for device implantation. The mean age at time of ILR insertion was 11.39 +/- 4.34 (range, 2.0-16.8) years. The indications for ILR were recurrent syncope (n = 11), presyncope (n = 3) or palpitations (n = 9). Four (17.4%) patients had structural heart disease, three (13%) had a positive family history of sudden cardiac death and one (4%) had perinatal arrhythmia. One patient required ILR repositioning, and pocket infection necessitated explantation in one further patient. Minimum follow-up was 7.8 months during which symptoms were reported in 15 (65.2%) patients post-ILR insertion. Eight (34.7%) remained asymptomatic. Of the 15 who experienced symptom recurrence, eight (53.3%) had an arrhythmia recorded. Tachycardias recorded were polymorphic ventricular tachycardia (n = 1) and supraventricular tachycardia (n = 5). Clinically significant bradycardias documented, included sinus arrest (n = 1) and Mobitz type II second degree atrioventricular block (n = 1). The ILR had a high diagnostic yield, enabling an arrhythmic or non-arrhythmic diagnosis in 65.2% of patients with recurrent syncope, presyncope or palpitations in a selected paediatric population.

HIV testing in dementia: clinical, ethical and patient safety implications

This article presents patient safety issues along with the professional and ethical challenges in relation to UK guidelines on HIV testing in patients who are incapacitated as a result of dementia. Current protocols are designed to protect the patient, but may have undesirable consequences for patients, carers and doctors.

Patent ductus arteriosus evaluation by serial echocardiography in preterm infants

BACKGROUND

Patent ductus arteriosus (PDA) is associated with morbidity and mortality in premature neonates.

METHODS

The effect of serial echocardiography performed by a neonatologist and early targeted medical PDA treatment was evaluated and compared to historical controls. One hundred ninety-two infants <1,500 g were included and 45 infants had a PDA.

RESULTS

Serial echocardiography allowed significantly earlier identification and treatment of PDA versus awaiting the evolution of clinical signs. Severe intraventricular haemorrhage and ventilator days were significantly decreased in the studied cohort following the introduction of echocardiography. In addition, hospital stay was also reduced in the non-PDA group and other outcomes were unchanged.

CONCLUSION

Serial echocardiography for PDA evaluation, performed by a neonatologist trained in echo, may reduce morbidity in preterm infant.

Ageing is associated with diminished apoptotic cell clearance in vivo

Ageing leads to immune system dysfunction and the accumulation of autoantibodies. Because the rapid phagocytic clearance of apoptotic cells is required to prevent the development of autoimmunity, we examined the relative clearance of apoptotic material in young and aged mice using two independent assays. First, 2-year-old mice were found to be impaired in their ability to clear apoptotic keratinocytes following ultraviolet irradiation of the skin. Secondly, peritoneal macrophages exposed to apoptotic Jurkat T cells in vivo displayed diminished phagocytic activity in aged mice compared with 8-week-old mice. Consistent with these findings, aged mice exhibited signs of autoimmunity with the appearance of anti-nuclear antibodies and increased kidney glomerular size as well as complement deposits within the glomeruli. In vitro assays revealed that the pretreatment of macrophages with the serum from aged mice led to a reduction in their ability to phagocytose apoptotic bodies compared with macrophages treated with serum from young mice. These data show that the ageing process is accompanied by a diminished ability to clear apoptotic debris. This accumulation of apoptotic debris could contribute to immune system dysfunction that occurs in aged organisms.

Alveolar macrophage activation and an emphysema-like phenotype in adiponectin-deficient mice

Adiponectin is an adipocyte-derived collectin that acts on a wide range of tissues including liver, brain, heart, and vascular endothelium. To date, little is known about the actions of adiponectin in the lung. Herein, we demonstrate that adiponectin is present in lung lining fluid and that adiponectin deficiency leads to increases in proinflammatory mediators and an emphysema-like phenotype in the mouse lung. Alveolar macrophages from adiponectin-deficient mice spontaneously display increased production of tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase (MMP-12) activity. Consistent with these observations, we found that pretreatment of alveolar macrophages with adiponectin leads to TNF-alpha and MMP-12 suppression. Together, our findings show that adiponectin leads to macrophage suppression in the lung and suggest that adiponectin-deficient states may contribute to the pathogenesis of inflammatory lung conditions such as emphysema.

Evaluation of ideal irrigation fluid in ‘Greenlight’ photoselective vapourization of the prostate

Although many anecdotal opinions are available that water gives a better visual quality, no studies have analysed the differences in the visual quality of the operative field with the use of either saline or sterile water. As part of a prospective audit we wished to assess the effect of differing irrigant fluids on intraoperative visibility during Greenlight photoselective vapourization of prostate (PVP). Twenty-nine consecutive patients with prostates less than 100 cm(3) who underwent PVP were studied. The irrigation fluid used was randomly connected on a bag-by-bag basis, with the surgeon blinded to the bag's contents. Towards the end of each bag the surgeon gave a score to the quality of vision. All surgeons were familiarized with the vision scoring system in advance. The scores were analysed in two ways. The mean scores for water and saline were compared. In addition, a mean score for each fluid in each patient where both fluids were used (n=24) was separately calculated and the means for each fluid compared. One hundred and twenty-four bags of fluid in 29 operative cases were analysed. The mean overall vision scores were 3.94% for saline and 4.01% for water (P=0.62). The paired data were analysed using the Student's t-test and there was no statistically significant difference (P=0.34). We showed no significant difference in visual quality between water and saline during PVP. Although fluid absorption is almost unknown with PVP, there seems to be no justification for using water irrigation if saline is available, particularly with a theoretical risk of absorption.

Eliciting repeat blood donations: tell early career donors why their blood type is special and more will give again

BACKGROUND AND OBJECTIVES

This study was designed to investigate whether sending a personalized and informative letter to early career donors would increase the number returning to donate again, as the literature suggests that it is at around the third donation that people become career donors.

MATERIALS AND METHODS

Experimental participants were sent a recruitment letter that included information about their own blood type and the percentage of the general population with the same blood type who donated. Control participants received a recruitment letter with some general information. The aim of the study was to determine whether more participants in the experimental group, compared with the control group, would donate blood within a 4-week period after receiving their personalized recruitment letter.

RESULTS

Donors in the experimental group were 43% more likely to return to donate than those in the control group [chi(2) (1) = 5.79, P < 0.016].

CONCLUSIONS

Sending out personalized, informative letters appears to be a potentially powerful donor-retention tool.

Laparoscopic partial nephrectomy using the potassium titanyl phosphate laser in a porcine model

INTRODUCTION

To evaluate the potential and feasibility of the potassium titanyl phosphate (KTP) Greenlight laser to perform partial nephrectomy in a porcine model.

TECHNICAL CONSIDERATIONS

A total of 15 laparoscopic partial nephrectomies were performed in 4 Danish land-raised pigs under anesthesia. Transperitoneal access was obtained, and using a total of four ports, the 80-W KTP laser was used to perform bilateral upper and lower pole partial nephrectomy. The procedures were done successfully without renal cooling or clamping of the vessels. The estimated blood loss for each procedure was less than 30 mL. Only in one operation, in which a secondary renal vein was transected, was any additional hemostasis required (a single Endoclip). The mean operating time was 42 minutes (range 31 to 59) for each partial nephrectomy. As demonstrated on video, smoke formation was, at times, a problem during the procedure, because it reduced visibility, making only intermittent application of laser energy possible. Histopathologic analysis of the specimens showed a zone of loss of substance (less than 1 mm) at the resection line and narrow adjacent zones on both sides of the resection line with minimal changes.

CONCLUSIONS

We have shown for the first time that normally perfused laparoscopic partial nephrectomy using the KTP laser is feasible and efficacious in the porcine model. This represents a novel application for the KTP laser, which produced excellent renal parenchymal hemostatic ablation. We are currently working on ways to improve the visibility by reducing smoke formation before undertaking a clinical trial in humans.

Use of expired breath ethanol measurements in evaluation of irrigant absorption during high-power potassium titanyl phosphate laser vaporization of prostate

OBJECTIVES

To evaluate formally the risk and levels of irrigant absorption during high-power potassium titanyl phosphate (KTP) laser vaporization of the prostate by the Greenlight PV system using the expired breath ethanol technique.

METHODS

Forty consecutive patients underwent laser vaporization of the prostate. Of these patients, 17 had a preoperative transrectal ultrasound estimation of the prostate volume (mean 97 cm3). All procedures were performed under general anesthesia, by either of two consultants or a trainee. A 1% ethanol solution was used as irrigation fluid. Throughout the operation, the expired breath was analyzed for ethanol using a standard alcometer "plumbed" into the anesthetic circuit. Venous blood samples were taken immediately before and after the procedure for measurements of serum sodium and plasma alcohol levels.

RESULTS

On average, 155,000 J of laser energy was delivered in 47 minutes. In all patients and on all occasions, the expired breath ethanol remained at 0. No statistically significant change was found in the serum sodium concentration during the procedure (P = 0.42), and no patient displayed any clinical evidence of transurethral resection syndrome.

CONCLUSIONS

The results of this study have confirmed, for the first time, the lack of significant absorption of irrigation fluid during high-power KTP vaporization of the prostate using a recognized sensitive technique and the safety of using sterile water as that irrigant. This was the case even in those patients with very large prostates who are usually considered at high risk of experiencing the clinical consequences of fluid absorption during transurethral resection of the prostate and regardless of the experience of the surgeon.

Use of quantitative molecular diagnostic assays to investigate fusarium dry rot in potato stocks and soil

ABSTRACT Specific and sensitive quantitative diagnostics, based on real-time (TaqMan) polymerase chain reaction (PCR) and PCR enzyme-linked immunosorbent assay, were developed to detect dry-rot-causing Fusarium spp. (F. avenaceum, F. coeruleum, F. culmorum, and F. sulphureum). Each assay detected Fusarium spp. on potato seed stocks with equal efficiency. Four potato stocks, sampled over two seed generations from Scottish stores, were contaminated with F. avenaceum, F. sulphureum, F. culmorum, F. coeruleum or a combination of species, and there was a general trend towards increased Fusarium spp. contamination in the second generation of seed sampled. F. sulphureum and F. coeruleum caused significantly (P < 0.05) more disease in storage than the other species when disease-free tubers of potato cvs. Spunta and Morene were inoculated at a range of inoculum concentrations (0, 10(4), 10(5), and 10(6) conidia/ml). Increased DNA levels were correlated with increased disease severity between 8 and 12 weeks of storage. The threshold inoculum levels resulting in significant disease development on both cultivars were estimated to be 10(4) conidia/ml for F. sulphureum and 10(5) conidia/ml for F. coeruleum. To study the effect of soil infestation and harvest date on disease incidence, seed tubers of cvs. Morene and Spunta were planted in a field plot artificially infested with the four Fusarium spp. F. culmorum and F. sulphureum were detected in soil taken from these plots at harvest, and F. sulphureum DNA levels increased significantly (P < 0.05) at the final harvest. All four Fusarium spp. were detected in progeny tubers. There was a trend toward higher levels of F. culmorum detected in progeny tubers at the earliest harvest date, and higher levels of F. sulphureum at the final harvest. The use of diagnostic assays to detect fungal storage rot pathogens and implications for disease control strategies are discussed.

Deep Impact: observations from a worldwide Earth-based campaign

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

Difficult airway equipment in obstetric units in the republic of Ireland: results of a national survey

BACKGROUND AND OBJECTIVE

Difficult intubation in obstetric units has been identified as a major contributory factor to anaesthesia related maternal morbidity and mortality. Availability of equipment for management of a difficult airway is associated with reduced maternal complications. The purpose of our survey was to describe the availability of difficult airway equipment in Irish Obstetric Units.

METHODS

A telephone survey was conducted in which all respondents were asked whether they housed basic airway equipment, alternative ventilation and alternative intubation equipment within or close to their obstetric unit.

RESULTS

The most important finding of this study is that all the obstetric units in Ireland hold at least one alternative device for both ventilation and intubation. The most common alternative ventilation device was the laryngeal mask airway and the most common alternative intubating device was the surgical airway device.

CONCLUSIONS

Irish Obstetric Units are well equipped according to the international guidelines for difficult intubation equipment. However, we believe that this situation could be further improved by training inexperienced anaesthetists in the use of the Intubating Laryngeal Mask and by the increased use of portable trolleys.

Anaesthetic specialist registrars in Ireland: current teaching practices and perceptions of their role as undergraduate teachers

BACKGROUND AND OBJECTIVES

Teaching is an important responsibility of non-consultant hospital doctors. In Ireland, specialist registrars (SpRs) in anaesthesia are contractually obliged to teach medical students, other doctors and nurses. Both medical students and fellow non-consultant hospital doctors attribute between 30 and 40% of their knowledge gain to non-consultant hospital doctors.

METHODS

We carried out a confidential telephone survey of anaesthetic SpRs in Ireland regarding their current teaching practices and the perceptions of their role as undergraduate teachers. All the SpRs currently working in clinical practice in Ireland were eligible.

RESULTS

Fifty-five of the 79 (70%) SpRs responded to the questionnaire. Only 7 (12.7%) of the respondents said they had been well trained as a teacher. The majority of the respondents stated that they would attend a learning-to-teach course/workshop if one was available, and felt that such a course would improve their ability as a teacher. Only 8 (14.5%) agreed that adequate emphasis is placed on commitment to teaching in the assessment of SpRs, both by individual departments and by the College of Anaesthetists. Anaesthetic SpRs in Ireland spend a considerable amount of time each day teaching undergraduate medical students, the majority (68.9%) stated that they had inadequate time to prepare for teaching.

CONCLUSION

The majority of the respondents stated that they enjoy teaching, feel that they play an important role in undergraduate teaching but have inadequate time to prepare for teaching. An adequate emphasis is not placed on their commitment to teaching.

Difficult airway equipment in departments of emergency medicine in Ireland: results of a national survey

BACKGROUND AND OBJECTIVE

Adverse effects associated with difficult airway management can be catastrophic and include death, brain injury and myocardial injury. Closed-malpractice claims have shown prolonged and persistent attempts at endotracheal intubation to be the most common situation leading to disastrous respiratory events. To date, there has been no evaluation of the types of difficult airway equipment currently available in Irish departments of emergency medicine. The objective of this survey was to identify the difficult airway equipment available in Irish departments of emergency medicine.

METHODS

Departments of emergency medicine in the Republic of Ireland with at least one dedicated Emergency Medicine consultant were surveyed via telephone.

RESULTS

All of the departments contacted held at least one alternative device on site for both ventilation and intubation. The most common alternative ventilation device was the laryngeal mask airway (89%). The most common alternative intubating device was the surgical airway device (100%).

CONCLUSIONS

Irish departments of emergency medicine compare well with those in the UK and USA, when surveyed concerning difficult airway equipment. However, we believe that this situation could be further improved by training inexperienced healthcare providers in the use of the laryngeal mask airway and intubating laryngeal mask airway, by placing greater emphasis on the ready availability of capnography and by the increased use of portable difficult airway storage units.

A randomised trial of periprostatic local anaesthetic for transrectal biopsy

Increasingly transrectal ultrasound and biopsy is performed for the detection of prostate cancer. We have conducted a randomised trial to evaluate whether the addition of periprostatic local anaesthetic injection reduces the discomfort of the procedure. A total of 64 patients who attended a specialised prostate clinic and were being evaluated for an elevated prostate-specific antigen agreed to participate in the trial and were randomly allocated to two groups. The intervention group received 10 ml of 1% lignocaine in the periprostatic tissue prior to biopsy and the control group underwent a standard biopsy. All patients had a sextant biopsy under ultrasound guidance. After the procedure, they were asked to determine the severity of the pain on a scale of 0-10 and the whether the quality of the pain was mild, moderate or severe. The responses were distributed normally. The groups were compared using Student's t-test. Pain severity showed no significant difference between the two groups (P=0.14). There was a trend towards a statistical difference (P=0.07) on the qualitative pain scale. In conclusion, no significant difference in overall discomfort in men having sextant biopsies was detected between the two groups, suggesting that the administration of local anaesthetic may not be as valuable as early reports have suggested.