Impact of repeated micro and macro blood sampling on clinical chemistry and haematology in rats for toxicokinetic studies

Non-clinical rodent safety studies are essential in the development of new medicines to assess for potential adverse effects. Typically, toxicokinetic samples are collected from a satellite group. AstraZeneca implemented repeated microsampling of main study animals as standard in the one-month small molecule regulatory toxicology studies. A retrospective analysis of the clinical chemistry and haematology data collected in 52 independent studies from the adult rat controls explored the impact of micro and macro sampling of main study animals. For the majority of variables, the blood sampling technique had no significant impact on the mean or range. For microsampling, a few variables had statistically significant effects on the mean signal but these were considered to have limited biological relevance and would therefore not introduce a meaningful bias to any toxicological evaluation. The macrosampling had the expected effects on the red cell parameters of haemoglobin, haematocrit and red blood count due to the larger blood volume draw. In contrast, microsampling showed no such changes. In conclusion, this large-scale retrospective analysis supports the use of microsampling, for toxicokinetics, of main study animals and enables us to conduct rodent toxicology studies without satellite animals and further reduce the number of animals used in toxicological assessments.

SARS-CoV-2 Spike Protein Expression In Vitro and Hematologic Effects in Mice Vaccinated With AZD1222 (ChAdOx1 nCoV-19)

Severe COVID-19 can be associated with a prothrombotic state, increasing risk of morbidity and mortality. The SARS-CoV-2 spike glycoprotein is purported to directly promote platelet activation via the S1 subunit and is cleaved from host cells during infection. High plasma concentrations of S1 subunit are associated with disease progression and respiratory failure during severe COVID-19. There is limited evidence on whether COVID-19 vaccine-induced spike protein is similarly cleaved and on the immediate effects of vaccination on host immune responses or hematology parameters. We investigated vaccine-induced S1 subunit cleavage and effects on hematology parameters using AZD1222 (ChAdOx1 nCoV-19), a simian, replication-deficient adenovirus-vectored COVID-19 vaccine. We observed S1 subunit cleavage in vitro following AZD1222 transduction of HEK293x cells. S1 subunit cleavage also occurred in vivo and was detectable in sera 12 hours post intramuscular immunization (1x10¹⁰ viral particles) in CD-1 mice. Soluble S1 protein levels decreased within 3 days and were no longer detectable 7–14 days post immunization. Intravenous immunization (1x10⁹ viral particles) produced higher soluble S1 protein levels with similar expression kinetics. Spike protein was undetectable by immunohistochemistry 14 days post intramuscular immunization. Intramuscular immunization resulted in transiently lower platelet (12 hours) and white blood cell (12–24 hours) counts relative to vehicle. Similarly, intravenous immunization resulted in lower platelet (24–72 hours) and white blood cell (12–24 hours) counts, and increased neutrophil (2 hours) counts. The responses observed with either route of immunization represent transient hematologic changes and correspond to expected innate immune responses to adenoviral infection.

Abstract 1374: The novel PARP1-selective inhibitor AZD5305 has reduced hematological toxicity when compared to PARP1/2 inhibitors in pre-clinical models

Current clinical poly (ADP-ribose) polymerase (PARP) inhibitors target both PARP1 and PARP2 and they all cause clinical cytopenias with varying severity. Understanding the mechanism underlying the hematological toxicity of these agents is key for the rational design of a best-in-class molecule with greater therapeutic potential, both as monotherapy and in combination with chemotherapy.

We validated the rat as a physiologically competent translational model to investigate PARP inhibitor-driven hematological toxicity. Here we demonstrate that in comparison with a representative PARP1/2 inhibitor, olaparib, the novel highly potent PARP1-selective inhibitor and trapper, AZD5305, does not cause hematological toxicity as a monotherapy in pre-clinical rat models at predicted clinically efficacious exposures. Thus, monotherapy toxicity of PARP1/2 inhibitors likely depends on PARP2 inhibition.

Next, we proceeded to investigate whether PARP1-selective inhibition would be better tolerated in chemotherapy combinations than PARP1/2 inhibition. We performed a rat in vivo study comparing daily olaparib or daily AZD5305 at matched exposures in combination with one cycle of intravenous carboplatin for 14 days. We show that olaparib and PARP1-selective AZD5305 cause comparable exacerbation of carboplatin-induced peripheral blood effects implicating PARP1 inhibition in combination-driven hematological toxicity. Importantly however, AZD5305+carboplatin showed improved hematological tolerability over olaparib+carboplatin because peripheral reticulocytes and bone marrow erythroid precursor cells recover in the presence of continuous AZD5305 but not in the presence of continuous olaparib. Importantly, this differentiation was maintained in a subsequent rat in vivo study, where daily olaparib or daily AZD5305 were combined with two three-weekly cycles of a higher dose of carboplatin to more closely mimic clinical protocol. AZD5305+carboplatin was associated with a more rapid recovery of reticulocytes, red blood cells and hemoglobin following both cycles of carboplatin. In contrast, olaparib+carboplatin was associated with a slower recovery resulting in a more sustained reduction in red cells and hemoglobin during both the first and second cycle of carboplatin.

Thus, in rodents the novel potent PARP1-selective inhibitor AZD5305 has improved hematological tolerability over dual PARP1/2 inhibitors, both as a monotherapy and in carboplatin combinations.

Citation Format: Sonja J. Gill, Ruth Macdonald, Carmen Pin, Rob Collins, Emilyanne Leonard, Gareth Maglennon, Andy Pike, Peter Cotton, Glen Hawthorne, Jordan Pugh, Rebecca Sargeant, Daniel Sutton, James Atkinson, Stewart Jones, Sarah Chinery, Mark Anderton. The novel PARP1-selective inhibitor AZD5305 has reduced hematological toxicity when compared to PARP1/2 inhibitors in pre-clinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1374.

Maintaining the blind in sham controlled interventional trials: lessons from the EPISOD study

Objective and study aims  This study was designed to demonstrate the techniques used and the effectiveness of blinding in the EPISOD study (Evaluating Predictors and Interventions in Sphincter of Oddi Dysfunction). This was a large sham-controlled trial evaluating the efficacy of endoscopic sphincterotomy treatment for patients with suspected sphincter of Oddi dysfunction. Patients and methods  We describe the methods intended to ensure that the subjects, caregivers and those assessing the outcomes were blinded to the treatment allocation and systematically assess the success of subject blinding procedures using the Bang's Blinding Index (BI) for each treatment arm as an indicator of potential unblinding. Results  Blinding procedures proved to be acceptable and adhered to by the study team at each site. The BI indicated "wishful thinking" by the subjects regardless of treatment assignment, even when they were confident in their opinions. Conclusion  We conclude that it is possible to design and maintain a system for blinding the treatment allocation in a sham-controlled interventional study. Treatment guess plus confidence in the guess should be collected to examine the success of blinding procedures. The EPISOD study provides a blueprint for future sham-controlled trials in endoscopy.

Abstract 3721: A camptothecin-containing nanoparticle-drug conjugate combination with DDR agents provides a novel approach to increasing therapeutic index

Topoisomerase I inhibitors are used as standard-of-care chemotherapy in many types of cancer but are associated with significant toxicities. There is potential to improve their efficacy further by combining with inhibitors of the DNA damage response, such as the PARP inhibitor olaparib. However, while preclinical data highlight the improved efficacy of this combination, subsequent clinical trials have struggled due to dose limiting myelotoxicity.

CRLX101 is an investigational nanoparticle-drug conjugate (NDC) containing the payload camptothecin (the most potent topoisomerase I inhibitor known). This agent is preferentially targeted to tumours and demonstrated a favourable toxicity profile in the clinic.

Here, we explored the molecular mechanism and therapeutic potential of combining CRLX101 with either olaparib or the WEE1 inhibitor AZD1775, by testing both efficacy and safety in preclinical models. In vitro studies using NCI-H417a SCLC cells demonstrated that combination with both olaparib and AZD1775 potentiated the efficacy of CRLX101 although by different mechanisms. Cellular analyses revealed that CRLX101 treatment alone predominantly activated ATM-mediated DNA damage response and resulted in late S/G2 cell cycle arrest. Combination with a PARP inhibitor further enhanced the CRLX101-induced DNA damage response and prolonged cell cycle arrest in late S/G2 phase. In contrast, WEE1 inhibition abrogated late S/G2 cell cycle arrest induced by CRLX101, resulting in aberrant mitotic entry and enhanced cell death.

Our in vivo studies using wild type Wistar rat model showed that CRLX101, olaparib and AZD1775, are well tolerated as single agents. However, concurrent combination of CRLX101 with either olaparib or AZD1775 resulted in a dose-dependent decrease in haematological parameters. We investigated sequenced schedules and demonstrated that at a 24h delay between the CRLX101 and olaparib mitigates much of the combined bone marrow toxicity, while improving the efficacy above CRLX101 alone in xenograft tumours from NCI-H417a cells.

Collectively, these preclinical data demonstrate increased anti-tumour efficacy of CRLX101 when combined with DDR inhibitors. The combination schedule for CRLX101 and olaparib identified in our preclinical models as providing an increased therapeutic index has been used to develop protocols to test this combination in a relapsed (2nd line) SCLC human clinical trial (in collaboration with NCI).

Citation Format: Lenka Oplustil O’Connor, Anderson T. Wang, David R. Jones, Rajesh Odedra, Michael Spreadborough, Joanne Wilson, Aaron Smith, Peter Cotton, Jaimini Reens, Jen Barnes, Victoria Sheridan, Scott Eliasof, Andres Tellez, Alan Lau, Claire Sadler, Mark J. O’Connor. A camptothecin-containing nanoparticle-drug conjugate combination with DDR agents provides a novel approach to increasing therapeutic index. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3721.

Somatic tinnitus prevalence and treatment with tinnitus retraining therapy

OBJECTIVES

Somatic tinnitus originates from increased activity of the dorsal cochlear nucleus, a cross-point between the somatic and auditory systems. Its activity can be modified by auditory stimulation or somatic system manipulation. Thus, sound enrichment and white noise stimulation might decrease tinnitus and associated somatic symptoms. The present uncontrolled study sought to determine somatic tinnitus prevalence among tinnitus sufferers, and to investigate whether sound therapy with counselling (tinnitus retraining therapy; TRT) may decrease tinnitus-associated somatic symptoms.

METHODS

To determine somatic tinnitus prevalence, 70 patients following the TRT protocol completed the Jastreboff Structured Interview (JSI) with additional questions regarding the presence and type of somatic symptoms. Among 21 somatic tinnitus patients, we further investigated the effects of TRT on tinnitus-associated facial dysesthesia. Before and after three months of TRT, tinnitus severity was evaluated using the Tinnitus Handicap Inventory (THI), and facial dysesthesia was assessed with an extended JSI-based questionnaire.

RESULTS

Among the evaluated tinnitus patients, 56% presented somatic tinnitus-including 51% with facial dysesthesia, 36% who could modulate tinnitus by head and neck movements, and 13% with both conditions. Self-evaluation indicated that TRT significantly improved tinnitus and facial dysesthesia in 76% of patients. Three months of TRT led to a 50% decrease in mean THI and JSI scores regarding facial dysesthesia.

CONCLUSIONS

Somatic tinnitus is a frequent and underestimated condition. We suggest an extension of the JSI, including specific questions regarding somatic tinnitus. TRT significantly improved tinnitus and accompanying facial dysesthesia, and could be a useful somatic tinnitus treatment.

Spontaneous Pathology and Routine Clinical Pathology Parameters in Aging Beagle Dogs

AstraZeneca ran a bespoke study to generate age-matched clinical pathology and histopathology data from a cohort of Beagle dogs aged between 25 and 37 months to support the use of these older animals in routine preclinical toxicology studies. As the upper age range of Beagle dogs routinely used in toxicology studies does not normally exceed 24 months, there is an absence of appropriate age-matched historical control data. The generation of such data was crucial to understand whether age-related differences in spontaneous findings might confound the interpretation of toxicology study data. While the majority of the histopathology findings in all the older dogs occurred at a similar prevalence as those expected in young adult dogs (<24 months), a number of differences were observed in the thymus (involution), bone marrow (increased adiposity), testes (degenerative changes), and lung (fibrosis, pigment and alveolar hyperplasia) that could be misinterpreted as a test article effect. Minor differences in some clinical pathology values (hemoglobin, alkaline phosphatase, absolute reticulocytes) were of a small magnitude and considered unlikely to affect the interpretation of study data.

Endoscope storage time: assessment of microbial colonization up to 21 days after reprocessing

BACKGROUND

Insufficient data exist for how long endoscopes can be stored after reprocessing. Concern about possible microbial colonization has led to various recommendations for reprocessing intervals among institutions, with many as short as 5 days. A significant cost savings could be realized if it can be demonstrated that endoscopes may be stored for as long as 21 days without risk of clinically significant contamination.

OBJECTIVE

To demonstrate whether flexible endoscopes may be stored for as long as 21 days after reprocessing without colonization by pathogenic microbes.

DESIGN

Prospective, observational study.

SETTING

Tertiary care center.

ENDOSCOPES

Four duodenoscopes, 4 colonoscopes, and 2 gastroscopes.

INTERVENTION

Microbial testing of endoscope channels.

MAIN OUTCOME MEASUREMENTS

Culture results at days 0, 7, 14, and 21.

RESULTS

There were 33 positive cultures from 28 of the 96 sites tested (29.2% overall contamination rate). Twenty-nine of 33 isolates were typical skin or environmental contaminants, thus clinically insignificant. Four potential pathogens were cultured, including Enterococcus, Candida parapsilosis, α-hemolytic Streptococcus, and Aureobasidium pullulans; all were likely clinically insignificant as each was only recovered at 1 time point at 1 site, and all grew in low concentrations. There were no definite pathogenic isolates.

LIMITATIONS

Single center.

CONCLUSION

Endoscopes can be stored for as long as 21 days after standard reprocessing with a low risk of pathogenic microbial colonization. Extension of reprocessing protocols to 21 days could effect significant cost savings.

Glasgow supported self-management trial (GSuST) for patients with moderate to severe COPD: randomised controlled trial

OBJECTIVE

To determine whether supported self management in chronic obstructive pulmonary disease (COPD) can reduce hospital readmissions in the United Kingdom.

DESIGN

Randomised controlled trial.

SETTING

Community based intervention in the west of Scotland.

PARTICIPANTS

Patients admitted to hospital with acute exacerbation of COPD.

INTERVENTION

Participants in the intervention group were trained to detect and treat exacerbations promptly, with ongoing support for 12 months.

MAIN OUTCOME MEASURES

The primary outcome was hospital readmissions and deaths due to COPD assessed by record linkage of Scottish Morbidity Records; health related quality of life measures were secondary outcomes.

RESULTS

464 patients were randomised, stratified by age, sex, per cent predicted forced expiratory volume in 1 second, recent pulmonary rehabilitation attendance, smoking status, deprivation category of area of residence, and previous COPD admissions. No difference was found in COPD admissions or death (111/232 (48%) v 108/232 (47%); hazard ratio 1.05, 95% confidence interval 0.80 to 1.38). Return of health related quality of life questionnaires was poor (n=265; 57%), so that no useful conclusions could be made from these data. Pre-planned subgroup analysis showed no differential benefit in the primary outcome relating to disease severity or demographic variables. In an exploratory analysis, 42% (75/150) of patients in the intervention group were classified as successful self managers at study exit, from review of appropriateness of use of self management therapy. Predictors of successful self management on stepwise regression were younger age (P=0.012) and living with others (P=0.010). COPD readmissions/deaths were reduced in successful self managers compared with unsuccessful self managers (20/75 (27%) v 51/105 (49%); hazard ratio 0.44, 0.25 to 0.76; P=0.003).

CONCLUSION

Supported self management had no effect on time to first readmission or death with COPD. Exploratory subgroup analysis identified a minority of participants who learnt to self manage; this group had a significantly reduced risk of COPD readmission, were younger, and were more likely to be living with others.

TRIAL REGISTRATION

Clinical trials NCT 00706303.

[Somatic tinnitus (review). A consequence of plasticity and bimodal integration in the dorsal cochlear nucleus]

Somatic tinnitus is a peculiar tinnitus type that can be defined as a tinnitus that can be modulated in intensity and/or pitch by manipulating some regions of the head and neck but also as tinnitus associated with facial pain or dysesthesis in the same area. Those areas are innervated by the trigeminal nerve and the cervical plexus. This can be explained by functional connections between the trigeminal system and the auditory brainstem and mid-brain. A literature overview shows how different messages coming from the head and neck are able to modulate the hearing information. Tinnitus is generated by an increase of the spontaneous discharges of the dorsal cochlear nucleus neurons, tonotopic reorganisation and an increase of the neural synchronism in the auditory cortex. Trigeminal stimulations have an influence on the activity of the dorsal cochlear nucleus especially in case of an associated hearing loss.

Canadian Association of Gastroenterology consensus guidelines on safety and quality indicators in endoscopy

BACKGROUND

Increasing use of gastrointestinal endoscopy, particularly for colorectal cancer screening, and increasing emphasis on health care quality, highlight the need for clearly defined, evidence-based processes to support quality improvement in endoscopy.

OBJECTIVE

To identify processes and indicators of quality and safety relevant to high-quality endoscopy service delivery.

METHODS

A multidisciplinary group of 35 voting participants developed recommendation statements and performance indicators. Systematic literature searches generated 50 initial statements that were revised iteratively following a modified Delphi approach using a web-based evaluation and voting tool. Statement development and evidence evaluation followed the AGREE (Appraisal of Guidelines, REsearch and Evaluation) and GRADE (Grading of Recommendations, Assessment, Development and Evaluation) guidelines. At the consensus conference, participants voted anonymously on all statements using a 6-point scale. Subsequent web-based voting evaluated recommendations for specific, individual quality indicators, safety indicators and mandatory endoscopy reporting fields. Consensus was defined a priori as agreement by 80% of participants.

RESULTS

Consensus was reached on 23 recommendation statements addressing the following: ethics (statement 1: agreement 100%), facility standards and policies (statements 2 to 9: 90% to 100%), quality assurance (statements 10 to 13: 94% to 100%), training, education, competency and privileges (statements 14 to 19: 97% to 100%), endoscopy reporting standards (statements 20 and 21: 97% to 100%) and patient perceptions (statements 22 and 23: 100%). Additionally, 18 quality indicators (agreement 83% to 100%), 20 safety indicators (agreement 77% to 100%) and 23 recommended endoscopy-reporting elements (agreement 91% to 100%) were identified.

DISCUSSION

The consensus process identified a clear need for high-quality clinical and outcomes research to support quality improvement in the delivery of endoscopy services.

CONCLUSIONS

The guidelines support quality improvement in endoscopy by providing explicit recommendations on systematic monitoring, assessment and modification of endoscopy service delivery to yield benefits for all patients affected by the practice of gastrointestinal endoscopy.

Combined bicarbonate conductance-impairing variants in CFTR and SPINK1 variants are associated with chronic pancreatitis in patients without cystic fibrosis

BACKGROUND & AIMS

Idiopathic chronic pancreatitis (ICP) is a complex inflammatory disorder associated with multiple genetic and environmental factors. In individuals without cystic fibrosis (CF), variants of CFTR that inhibit bicarbonate conductance but maintain chloride conductance might selectively impair secretion of pancreatic juice, leading to trypsin activation and pancreatitis. We investigated whether sequence variants in the gene encoding the pancreatic secretory trypsin inhibitor SPINK1 further increase the risk of pancreatitis in these patients.

METHODS

We screened patients and controls for variants in SPINK1 associated with risk of chronic pancreatitis and in all 27 exons of CFTR. The final study group included 53 patients with sporadic ICP, 27 probands with familial ICP, 150 unrelated controls, 375 additional controls for limited genotyping. CFTR wild-type and p.R75Q were cloned and expressed in HEK293 cells, and relative conductances of HCO(3)(-) and Cl(-) were measured.

RESULTS

SPINK1 variants were identified in 36% of subjects and 3% of controls (odds ratio [OR], 18.1). One variant of CFTR not associated with CF, p.R75Q, was found in 16% of subjects and 5.3% of controls (OR, 3.4). Coinheritance of CFTR p.R75Q and SPINK1 variants occurred in 8.75% of patients and 0.38% of controls (OR, 25.1). Patch-clamp recordings of cells that expressed CFTR p.R75Q showed normal chloride currents but significantly reduced bicarbonate currents (P = .0001).

CONCLUSIONS

The CFTR variant p.R75Q causes a selective defect in bicarbonate conductance and increases risk of pancreatitis. Coinheritance of p.R75Q or CF causing CFTR variants with SPINK1 variants significantly increases the risk of ICP.

Measuring episodic abdominal pain and disability in suspected sphincter of Oddi dysfunction

AIM

To evaluate the reliability of an instrument that measures disability arising from episodic abdominal pain in patients with suspected sphincter of Oddi dysfunction (SOD).

METHODS

Although several treatments have been utilized to reduce pain and associated disability, measurement tools have not been developed to reliably track outcomes. Two pilot studies were conducted to assess test-retest reliability of a newly developed instrument, the recurrent abdominal pain intensity and disability (RAPID) instrument. The RAPID score is a 90-d summation of days where productivity for various daily activities is reduced as a result of abdominal pain episodes, and is modeled after the migraine disability assessment instrument used to measure headache-related disability. RAPID was administered by telephone on 2 consecutive occasions in 2 consenting populations with suspected SOD: a pre-sphincterotomy population (Pilot I, n = 55) and a post-sphincterotomy population (Pilot II, n = 70).

RESULTS

The average RAPID scores for Pilots I and II were: 82 d (median: 81.5 d, SD: 64 d) and 48 d (median: 0 d, SD: 91 d), respectively. The concordance between the 2 assessments for both populations was very good: 0.81 for the pre-sphincterotomy population and 0.95 for the post-sphincterotomy population.

CONCLUSION

The described pilot studies suggest that RAPID is a reliable instrument for measuring disability resulting from abdominal pain in suspected SOD patients.

Minimal standard terminology for gastrointestinal endoscopy - MST 3.0

Standardization of the language of gastrointestinal endoscopy is becoming increasingly important on account of international collaboration, standardized documentation requirements, and computer-based reporting. Version 1 of the Minimal Standard Terminology (MST) was devised to facilitate this development, and, through broad international collaboration, the document was developed and tested further to produce version 2.0, published in 2000. The document forms the basis for computer software by offering standard minimal lists of terms to be used in the structured documentation of endoscopic findings. The ownership of the MST has been transferred to the World Organisation of Digestive Endoscopy (OMED) and in this context, a new revision of the MST document is now in place. Version 3.0 of the terminology includes terms for endoscopic ultrasound (EUS) and enteroscopy, as well as for adverse event reporting. In addition, acknowledged scoring systems have been included for specific findings, and some structural enhancements have been implemented. The entire document is freely available for noncommercial use from www.omed.org.

Designing clinical trials for NOTES

This article breaks down the elements of designing clinical trials, with an emphasis on randomized controlled trials, as applied to advancing natural orifice translumenal endoscopic surgery research. It discusses research ethics, feasibility, design elements (such as randomization, blinding, and choosing a primary outcome), and issues regarding presentation of results. The pros and cons of subjective quality of life outcomes are debated, and the role of the patient/consumer in driving the direction and interpretation of clinical trials is discussed.

Variation of agreement in polyp size measurement between computed tomographic colonography and pathology assessment: clinical implications

BACKGROUND & AIMS

Clinical management of polyps discovered by computed tomographic (CT) colonography depends on polyp size. However, size measured by CT colonography is an estimate, and its agreement with other measures is not well characterized. We hypothesized that size measurement by CT colonography varies substantially compared with measurement by other methods.

METHODS

We performed a secondary data analysis of a multicenter study of CT colonography in comparison with colonoscopy. Polyp size was determined by CT colonography, at colonoscopy, and measurement prefixation with a ruler. Agreement was assessed using descriptive statistics and Bland-Altman methodology.

RESULTS

Six hundred trial participants completed both tests. Ninety-five percent limits of agreement indicated that estimates of size by CT colonography were between 52% lower to 64% higher than prefixation polyp size estimates. Ninety-five percent limits of agreement stratified by categories of clinical importance indicated that estimates of size by CT colonography were between 44% lower to 84% higher for polyps 0.6 cm or smaller, 44% lower to 44% higher for polyps 0.6 to 0.9 cm, and 48% lower to 22% higher for polyps smaller than 0.6 cm, 44% lower to 44% higher for polyps 0.6 cm to 0.9 cm, and 48% lower to 22% higher for polyps larger than 0.9 cm compared with prefixation estimates. Analysis of participants with 1 identified polyp in the same colon segment showed that categorization based on CT colonography measurement (ie, <0.6 cm, 0.6-0.9 cm, or >0.9 cm) differed from prefixation measurement for 43% of participants.

CONCLUSIONS

Polyp size estimation by CT colonography varies from prefixation and colonoscopic measures of size. Future studies should clarify whether size estimation by CT colonography is sufficiently reliable as a primary factor to guide clinical management.

Occupational wellbeing--management of injured workers with psychosocial barriers

BACKGROUND

Although most injured workers return to work with minimal intervention, approximately 20% show levels of distress and disability beyond that expected for the injury. The level of morale in a workplace seems to play a major role in this. Workers who experience positive emotions leading to increased morale are more likely to be resilient following injury.

OBJECTIVE

It is important for general practitioners to recognise the nonclinical factors that exert a significant influence over employee wellbeing and return to work outcomes. Some management strategies are presented.

DISCUSSION

General practitioners who work collaboratively with all major stakeholders, who identify and manage psychosocial barriers early, who take an active role in promoting positive expectations, and who focus on the immediate problem rather than its industrial associations will achieve better outcomes for their injured patients.

Endoscopic pancreatic sphincterotomy for pancreas divisum by using a needle-knife or standard pull-type technique: safety and reintervention rates

BACKGROUND

Technical options for pancreatic sphincterotomy of the minor papilla for pancreas divisum include a needle-knife cut over a plastic stent and a standard pull-type cut with a sphincterotome.

OBJECTIVE

Our objective was to compare the frequency, safety, and intermediate-term efficacy of these 2 techniques at our institution.

PATIENTS AND METHODS

Retrospective review of the GI-Trac database from July 1994 to July 2004 for patients with pancreas divisum undergoing an initial minor papilla sphincterotomy.

INTERVENTIONS

Patients were separated into 2 groups on the basis of the endoscopic pancreatic sphincterotomy technique used, either a needle-knife sphincterotomy (NKS) or standard pull-type sphincterotomy (PTS). The groups were compared on the basis of need for any reintervention, restenosis rates, and complication rates with use of Cox proportional hazards models.

RESULTS

There were 133 patients (72%) in the NKS group and 51 (28%) in the PTS group. Clinical presentations were similar in the 2 groups. At a median follow-up of 5 years, additional endoscopic therapy including repeat endoscopic pancreatic sphincterotomy, endoscopic balloon dilation, stone extraction, or stenting was necessary in 29% of patients after NKS and in 26% after PTS. Papillary restenosis rates were 24% over a median follow-up of 6 years after NKS and 20% over a median follow-up of 5 years after PTS. Overall complication rates were similar in those undergoing NKS and PTS (8.3% vs 7.8%). Age less than 40 years independently predicted reintervention (hazard ratio 2.21) and restenosis (hazard ratio 2.41) (both P < .01).

CONCLUSIONS

NKS is used more than PTS for minor papilla sphincterotomy at our institution, but the 2 techniques appear equally safe and effective. Younger age may be associated with higher reintervention rates.

Immediate endoscopic closure of colon perforation by using a prototype endoscopic suturing device: feasibility and outcome in a porcine model (with video)

BACKGROUND

Perforation is an uncommon but potentially devastating complication of colonoscopy. Surgical closure is the standard of care. Immediate endoluminal closure of a perforation would avoid the morbidity and mortality associated with general anesthesia, laparotomy, and surgical repair.

OBJECTIVES

To evaluate the feasibility and safety of full-thickness endoscopic closure of colonic perforations with a prototype endoscopic suturing device, the Eagle Claw, in a porcine model.

DESIGN

Endoscopic animal experimental study of closure of colon perforation by using a porcine model.

SUBJECTS

Ten pigs were included in the study.

INTERVENTIONS

The Eagle Claw was used to close small perforations (1.5 to 2 cm) of the colon created by needle-knife with the animal under general anesthesia by using the endoluminal route. All animals received intravenous antibiotics and were allowed to eat after 24 hours.

MAIN OUTCOME MEASUREMENTS

The animals were monitored daily for signs of sepsis and peritonitis. On day 7, they were euthanized. The peritoneal cavity was examined for fecal peritonitis, and the colon perforation site was checked for wound dehiscence and pericolic abscess formation.

RESULTS

Endoscopic closure of the colon perforation was successful in 7 animals, and they recovered well without any sepsis or peritonitis. Necropsy did not reveal fecal peritonitis or pericolonic abscess formation at the site of perforation, and the perforation healed well. Closure was successful in 1 animal, but necropsy revealed dehiscence of the colon perforation site. Endoscopic closure was unsuccessful in 2 animals, and these were euthanized immediately.

CONCLUSIONS

Closure of acute perforation of the colon is feasible with the Eagle Claw endoscopic suturing device in a porcine model.

Widespread endoscopic mucosal resection of the esophagus with strategies for stricture prevention: a preclinical study

BACKGROUND AND STUDY AIMS

Circumferential endoscopic mucosal resection of the esophagus is complicated by stricture formation. Prophylactic measures for avoiding such strictures have not been well studied. The aim of this preclinical study was to assess strategies for prevention of esophageal strictures in a porcine model following widespread endoscopic mucosal resection (EMR).

METHODS

A total of 18 60-kg pigs were included in the study. The roles of strip width (group 1), prophylactic steroids (group 2), and prophylactic stents (group 3) in the prevention of post-mucosectomy strictures were studied. Six animals were included in each group. Esophageal mucosal resection was achieved using a novel widespread EMR technique previously described by our group. Animals in group 1 underwent partial (50% circumference) mucosal resection without prophylactic measures, while animals in the other two groups underwent circumferential mucosal resection. Animals in group 2 received 80 mg of triamcinolone injected directly into the exposed submucosal tissue (20 mg injection in four quadrants). Animals in group 3 received esophageal metal stents coated with small-intestine submucosa (SIS) that were deployed immediately post-resection. Animals were kept alive for 1 month.

RESULTS

Partial and circumferential widespread EMRs were achieved in all animals. There were no procedural complications. Repeat endoscopy at 1 month showed no strictures in group 1. Only four animals were studied in group 2, owing to the high complication rate (periesophageal abscess in all animals) with one early death. Three of the surviving animals developed mild to tight strictures. In group 3, all animals developed tight strictures; however, there was early stent migration in four animals and premature stent removal in two animals because of persistent vomiting.

CONCLUSIONS

Partial widespread EMR of the esophagus heals without stricture formation and does not require prophylactic intervention. The use of deep mural steroid injection following a circumferential resection does not appear to prevent strictures and may result in serious adverse events. Short-term use of esophageal stents is inadequate for stricture prevention. However, better results may be anticipated with longer term (at least 6 weeks) stent use.

Possible features of current electronic endoscopic information systems: what to look for

The endoscopic electronic medical record (EEMR) has the potential to increase greatly the efficiency of both the endoscopist and the entire endoscopy unit. Potential efficiencies depend on the specific situation of the endoscopist and the type of endoscopy unit. This article describes a number of features available in current EEMRs as well as some emerging features that are important for future databases. Additionally, some aspects of equipment and staff needed to implement a successful EEMR are discussed.

AGA future trends report: CT colonography

BACKGROUND & AIMS

Computed tomographic colonography (CTC) was first described more than a decade ago. Recent advances in imaging hardware and software and results of clinical trials based on new methods for performing and interpreting images suggest that CTC may now be assessed as a method for colorectal cancer screening.

METHODS

The Research Policy Committee of the American Gastroenterological Association assembled a task force to review the results of recent clinical trials and quantitative mathematical models pertaining to CTC. The goal of the task force was to assess the current knowledge about CTC and to evaluate the issues that will define its impact.

RESULTS

Limitations in evaluating the current state of CTC technology include a wide variation in results of clinical trials. There are as yet insufficient data on the use of CTC in routine clinical practice. Limitations in the use of quantitative mathematical models make predictions based on such models of limited value. The cancer risk and therefore clinical importance of small colorectal polyps detected by CTC and/or nonpolypoid neoplasia not detected by CTC remains largely unknown.

CONCLUSIONS

CTC is attractive as a colon imaging modality. It is therefore anticipated that CTC will have a significant impact on the practice of gastroenterology. However, the magnitude of the impact is currently unknown. Whether the ongoing implementation of CTC will increase or decrease the number of referrals for colonoscopy or shift the procedure from colorectal cancer screening to therapeutic interventions (e.g., polypectomy) is unknown at the present time. Multidisciplinary collaboration between gastroenterology and radiology to promote effective implementation and ongoing quality assurance will be important.

Characterization of a SNF1 homologue from the phytopathogenic fungus Sclerotinia sclerotiorum

In yeast, the SNF1 gene product is essential for the release of catabolic repression. We report the isolation and characterization of an SNF1 homologue from the necrotrophic pathogen Sclerotinia sclerotiorum. Ss snf1 encodes a 765-amino-acid protein in which the catalytic domain has an overall identity with the yeast proteins varying from 55 to 76% while the C-terminal half of Ss SNF1 has a weak homology of about 20% with the yeast sequences. Reverse transcription-polymerase chain reaction showed that its transcripts were weakly and constitutively expressed in planta and in vitro regardless of the nature of the carbon sources and of the presence or absence of glucose. Expression of Ss snf1 in yeast cells allowed the snf1 mutant cells to utilize sucrose, raffinose or glycerol for growth while expression of the Ss snf1 catalytic domain did not restore growth on raffinose or glycerol. Ss SNF1 is structurally homologous to Snf1p, suggesting that the interactions between the kinase and the accessory subunits to activate the enzymatic complex are conserved in fungi.

Long-term outcome in patients with benign biliary strictures treated endoscopically with multiple stents

BACKGROUND

The long-term efficacy of sequential insertion of multiple plastic stents for benign biliary strictures is poorly defined. The aims of this study were to evaluate the long-term outcome (bile duct patency, complications) of this therapy and to identify predictors of a good outcome.

METHODS

Retrospective review of 29 cases of benign biliary strictures treated with sequential plastic stent insertion in progressively increasing numbers and/or of increasing diameter.

RESULTS

Stricture etiology was as follows: postoperative 19 (66%), chronic pancreatitis 9 (31%), and idiopathic 1 (3%). Therapy succeeded in 18 patients (62%) (mean follow-up 48.0 [11.56] months after stent removal). Therapy failed in 11 patients (38%) (mean interval to failure 11.59 [9.79] months after stent removal). The 2 groups of patients in which therapy failed had either a hilar stricture (n = 4, 25% success) or distal common bile duct stricture caused by chronic pancreatitis (n = 9, 44% success). In the remaining cases, therapy succeeded in 13 of 16 (81% success). The observed differences in success rate among subgroups were not statistically significant. There were no ERCP-related deaths. One episode of mild pancreatitis and 2 episodes of cholangitis developed during 126 ERCPs over a period of stent insertion of 36 patient years.

CONCLUSIONS

In selected patients with benign biliary strictures, sequential endoscopic insertion of multiple biliary stents may lead to long-term success that could be equal to or superior to surgery with minimal morbidity. Hilar strictures and those caused by chronic pancreatitis appear to respond poorly to this therapy.

Expression and compartmentation of the glucose repressor CRE1 from the phytopathogenic fungus Sclerotinia sclerotiorum

The glucose repressor from the phytopathogenic fungus Sclerotinia sclerotiorum is encoded by the cre1 gene. Polyclonal antibodies were raised against a fusion protein (gluthathione S-transferase) GST-CRE1 in order to study cre1 expression. Western blot analyses revealed that CRE1 synthesis is regulated by the nature of the extracellular carbon source. High CRE1 levels are induced by glucose and remain stable after transfer into pectin medium, suggesting the existence of post-translational mechanisms which inactivate CRE1 to allow transcription of glucose-repressed genes. Subcellular fractionation demonstrated that CRE1 is localized in the nuclei of glucose grown hyphae and in the cytoplasm when glucose is removed from the culture medium. CRE1 fused to green fluorescent protein (GFP) was introduced into Aspergillus nidulans. Fluorescence microscopy showed the nuclear localization of the GFP-CRE1 fusion protein according to the presence of glucose in the culture medium, suggesting homologous post-translational regulations of glucose repressors in fungi. We propose that filamentous fungi regulate the activity of the glucose repressor by controlling its nuclear translocation.

The glucose repressor CRE1 from Sclerotinia sclerotiorum is functionally related to CREA from Aspergillus nidulans but not to the Mig proteins from Saccharomyces cerevisiae

We isolated the putative glucose repressor gene cre1 from the phytopathogenic fungus Sclerotinia sclerotiorum. cre1 encodes a 429 amino acid protein 59% similar to the carbon catabolite repressor CREA from Aspergillus nidulans. In addition to the overall amino acid sequence relatedness between CRE1 and CREA proteins, cre1 can functionally complement the A. nidulans creAd30 mutation as assessed by repression of the alcohol dehydrogenase I gene expression. The CREI region carrying the two zinc fingers is also very similar to the DNA binding domains of the Saccharomyces cerevisiae glucose repressors Mig1p and Mig2p. Despite the presence in the CRE1 protein of several motifs involved in the regulation of Miglp activity, cre1 cannot complement mig deficiencies in S. cerevisiae. These data suggest that glucose repression pathways may have evolved differently in yeasts and filamentous fungi.

Pancreatic sphincter hypertension increases the risk of post-ERCP pancreatitis

BACKGROUND AND STUDY AIMS

The reason for the increased risk of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP) in patients with sphincter of Oddi dysfunction is not known. This study sought to determine whether pancreatic sphincter hypertension might explain some of the increased risk.

PATIENTS AND METHODS

The incidence of pancreatitis was determined from a cohort of patients who underwent pancreatic sphincter manometry. Additional data collected included: pancreatic and biliary sphincter manometry results, distal bile duct diameter, chronic pancreatitis grade by pancreatography, and endoscopic treatments.

RESULTS

Ten of 32 patients (31%) with pancreatic sphincter hypertension developed post-ERCP pancreatitis, compared to one of 33 (3%) with normal pancreatic manometry (P = 0.002). Patients with pancreatic sphincter hypertension were more likely to undergo endoscopic treatments (88%) compared to those with normal manometry (27%) (P = 0.001). The distal bile duct diameter was significantly smaller (4.5 +/- 0.5 mm) in patients who developed post-ERCP pancreatitis than in those who did not (6.2 +/- 0.3) (P = 0.025). Patients with small distal bile duct diameters (< 5 mm) were three times more likely to develop post-ERCP pancreatitis than those with larger ducts (relative risk [RR] 3.1, 95% confidence interval [CI] 0.9, 10.7). Patients with pancreatic sphincter hypertension were ten times more likely to develop post-ERCP pancreatitis than those with normal pancreatic manometry (RR 10.3, 95% CI 1.5, 76.0). In patients with a small bile duct size, pancreatic sphincter hypertension substantially increased the risk compared to those with normal manometry (RR 18.1, 95% CI 1.1, 287.6).

CONCLUSIONS

Pancreatic sphincter hypertension greatly increases the risk of post-ERCP pancreatitis in patients undergoing treatment or evaluation, or both, for sphincter of Oddi dysfunction.