Inflammatory Bowel Disease Disability Index is a valid and reliable measure of disability in an English-speaking hospital practice and predicts long-term requirement for treatment escalation

Objective

The Inflammatory Bowel Disease Disability Index (IBD-DI) was developed according to WHO standards and has been validated in population-based cohorts. However, there are limited data on its relationship to various psychosocial and economic variables or its relevance to hospital clinical practice. The study aims were to determine the validity and reliability of the IBD-DI in an English-speaking hospital out-patient population and to evaluate its association with short and long-term disease activity.

Design/Methods

329 subjects were enrolled in a cross-sectional and longitudinal study assessing the IBD-DI and a range of quality of life, work impairment, depression, anxiety, body image, interpersonal, self-esteem, disease activity, symptom scoring scales in addition to long-term outcome.

Results

The IBD-DI had adequate structure, was internally consistent and demonstrated convergent and predictive validity and was reliable in test-retest study. Disability was related to female sex (p=0.002), antidepressant use (p<0.001), steroid use (p<0.001) and disease activity (p<0.001). Higher IBD-DI scores were associated with long-term disease activity and need for treatment escalation in univariate (p<0.001) and multivariate (p=0.002) analyses.

Conclusion

The IBD-DI is a valid and reliable measure of disability in English-speaking hospital populations and predicts long-term requirement for treatment escalation.

Reduced Serological Response to COVID-19 Booster Vaccine is Associated with Reduced B Cell Memory in Patients With Inflammatory Bowel Disease; VARIATION [VAriability in Response in IBD AgainsT SARS-COV-2 ImmunisatiON]

BACKGROUND AND AIMS

Patients with inflammatory bowel disease [IBD] have an attenuated response to initial COVID-19 vaccination. We sought to characterize the impact of IBD and its treatment on responses after the third vaccine against SARS-CoV-2.

METHODS

This was a prospective multicentre observational study of patients with IBD [n = 202] and healthy controls [HC, n = 92]. Serological response to vaccination was assessed by quantification of anti-spike protein [SP] immunoglobulin [Ig]G levels [anti-SPIgG] and in vitro neutralization of binding to angiotensin-converting enzyme 2 [ACE2]. Peripheral blood B-cell phenotype populations were assessed by flow cytometry. SARS-CoV-2 antigen-specific B-cell responses were assessed in ex vivo culture.

RESULTS

Median anti-SP IgG post-third vaccination in our IBD cohort was significantly lower than HCs [7862 vs 19 622 AU/mL, p < 0.001] as was ACE2 binding inhibition [p < 0.001]. IBD patients previously infected with COVID-19 [30%] had similar quantitative antibody response as HCs previously infected with COVID-19 [p = 0.12]. Lowest anti-SP IgG titres and neutralization were seen in IBD patients on anti-tumour necrosis factor [anti-TNF] agents, without prior COVID-19 infection, but all IBD patients show an attenuated vaccine response compared to HCs. Patients with IBD have reduced memory B-cell populations and attenuated B-cell responses to SARS-CoV-2 antigens if not previously infected with COVID-19 [p = 0.01]. Higher anti-TNF drug levels and zinc levels <65 ng/ml were associated with significantly lower serological responses.

CONCLUSIONS

Patients with IBD have an attenuated response to three doses of SARS-CoV-2 vaccine. Physicians should consider patients with higher anti-TNF drug levels and/or zinc deficiency as potentially at higher risk of attenuated response to vaccination.

Implementation of BSG/ACPGBI/PHE polypectomy surveillance guidelines safely reduces the burden of surveillance in a screening cohort: a virtual model study

OBJECTIVE

To evaluate the impact of British Society of Gastroenterology/Association of Coloproctology of Great Britain and Ireland/Public Health England (BSG/ACPGBI/PHE) 2019 polypectomy surveillance guidelines within a national faecal immunochemical test-based bowel cancer screening (BS) cohort on surveillance activity and detection of pathology by retrospective virtual application.

DESIGN

A retrospective review of BS colonoscopies performed in 2015-2016 with 5 years prospective follow-up in single institution. Index colonoscopies were selected. Incomplete colonoscopies were excluded. Histology of all resected polyps was reviewed. Surveillance intervals were calculated according to BSG/ACPGBI/PHE 2019 guidelines and compared with pre-existing 'European Guidelines for Quality Assurance in Colorectal Cancer Screening and Diagnosis' (EUQA 2013). Total number of colonoscopies deferred by virtual implementation of BSG/ACPGBI/PHE 2019 guidelines were calculated. Pathology identified on procedures that would have been deferred was reviewed.

RESULTS

Total number of index BS colonoscopies performed in 2015-2016 inclusive was 890. 115 were excluded (22 no caecal intubation, 51 inadequate bowel preparation, 56 incomplete polyp clearance). N=509 colonoscopies were scheduled within a 5-year interval following index colonoscopy surveillance rounds based on EUQA guidelines. Overall, volume of surveillance was significantly reduced with retrospective application of BSG/ACPGBI/PHE 2019 guidelines (n=221, p<0.0001). No cancers were detected within the 'potentially deferred' procedures who attended for follow-up (n=330) with high-risk findings found in<10% (n=30) of colonoscopies within the BSG/ACPGBI/PHE cohort.

CONCLUSION

BSG/ACPGBI/PHE 2019 guidelines safely reduce the burden of colonoscopy demand with acceptable pathology findings on deferred colonoscopies.

Reduced Serological Response to COVID-19 Vaccines in Patients with IBD is Further Diminished by TNF Inhibitor Therapy; Early Results of the VARIATION study [VAriability in Response in IBD Against SARS-COV-2 ImmunisatiON]

BACKGROUND AND AIMS

Evidence suggests patients with inflammatory bowel disease [IBD] receiving TNF antagonists have attenuated response to vaccination against COVID-19. We sought to determine the impact of IBD and of various medications for treatment of IBD on antibody responses to vaccination against COVID-19.

METHODS

Patients with IBD [n = 270] and healthy controls [HC, n = 116] were recruited prospectively, and quantitative antibody responses were assessed following COVID-19 vaccination. The impact of IBD and of medications for treatment of IBD on vaccine response rates was investigated.

RESULTS

Of HC, 100% seroconverted following complete vaccination with two vaccine doses; 2% of patients with IBD failed to seroconvert. Median anti-spike protein [SP] immunoglobulin [Ig]G levels following complete vaccination in our IBD cohort was significantly lower than among HC [2613 AU/mL versus 6871 AU/mL, p ≤0.001]. A diagnosis of IBD was independently associated with lower anti-SP IgG levels [β coefficient -0.2, p = 0.001]. Use of mRNA vaccines was independently associated with higher anti-SP IgG levels [β coefficient 0.25, p ≤0.001]. Patients with IBD receiving TNF inhibitors had significantly lower anti-SP IgG levels [2445 AU/mL] than IBD patients not receiving TNF inhibitors [3868 AU/mL, p ≤0.001]. Patients with IBD not receiving TNF inhibitors still showed attenuated responses compared with HC [3868 AU/mL versus 8747 AU/mL, p = 0.001].

CONCLUSIONS

Patients with IBD have attenuated serological responses to SARS-CoV-2 vaccination. Use of anti-TNF therapy negatively affects anti-SP IgG levels further. Patients who do not seroconvert following vaccination are a particularly vulnerable cohort. Impaired responses to vaccination in our study highlight the importance of booster vaccination programmes for patients with IBD.

Mucosal Healing in Crohn's Disease: Bull's Eye or Bust? "The Pro Position"

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory disorder affecting the gastrointestinal tract with disease behaviour based on the depth and severity of mucosal injury. Cumulative injury can result in complications including stricture formation and penetrating complications which often require surgical resection of diseased segments of the intestine resulting in significant morbidity. Accurate assessment of disease activity and appropriate treatment is essential in preventing complications.

SUMMARY

Treatment targets in the management of CD have evolved with the advent of more potent immunosuppressive therapy. Targeting the resolution of sub-clinical inflammation and achieving mucosal healing is associated with the prevention of stricturing and penetrating complications. Identifying non-invasive modalities to assess mucosal healing remains a challenge.

KEY MESSAGES

Mucosal healing minimizes the risk of developing disease complications, prolongs steroid-free survival, and reduces hospitalization and the need for surgical intervention.

Review Article: vaccination for patients with inflammatory bowel disease during the COVID-19 pandemic

BACKGROUND

Poor immune responses are frequently observed in patients with inflammatory bowel disease (IBD) receiving established vaccines; risk factors include immunosuppressants and active disease.

AIMS

To summarise available information regarding immune responses achieved in patients with IBD receiving established vaccines. Using this information, to identify risk factors in the IBD population related to poor vaccine-induced immunity that may be applicable to vaccines against COVID-19.

METHODS

We undertook a literature review on immunity to currently recommended vaccines for patients with IBD and to COVID-19 vaccines and summarised the relevant literature.

RESULTS

Patients with IBD have reduced immune responses following vaccination compared to the general population. Factors including the use of immunomodulators and anti-TNF agents reduce response rates. Patients with IBD should be vaccinated against COVID-19 at the earliest opportunity as recommended by International Advisory Committees, and vaccination should not be deferred because a patient is receiving immune-modifying therapies. Antibody titres to COVID-19 vaccines appear to be reduced in patients receiving anti-TNF therapy, especially in combination with immunomodulators after one vaccination. Therefore, we should optimise any established risk factors that could impact response to vaccination in patients with IBD before vaccination.

CONCLUSIONS

Ideally, patients with IBD should be vaccinated at the earliest opportunity against COVID-19. Patients should be in remission and, if possible, have their corticosteroid dose minimised before vaccination. Further research is required to determine the impact of different biologics on vaccine response to COVID-19 and the potential for booster vaccines or heterologous prime-boost vaccinations in the IBD population.

Irish data on the safety and efficacy of vedolizumab in the treatment of inflammatory bowel disease

This study reviews the safety and efficacy of treatment with vedolizumab for patients with inflammatory bowel disease across 9 Irish hospitals. It generates valuable and timely real-world data on treatment outcomes to add to the existing evidence base. Our population represents a refractory cohort with most patients previously exposed to at least one anti-TNFa agent and expressing an inflammatory phenotype. Results are reassuringly similar to larger international studies with additional insights into potential predictors of treatment response. This study further supports the safety and efficacy of vedolizumab in the treatment of inflammatory bowel disease. Key SummaryVedolizumab has growing real world data on its safety and efficacy in the treatment of IBD. Data on predictors of response are lacking. Studies such as VARSITY require new real-world data to help identify the place VDZ will occupy in the treatment algorithm for IBDThis study provides national Irish data on the safety and efficacy of VDZ in the treatment of IBD. It gives insight into various predictors of response for both UC and CD. It strengthens the available body of evidence on the use of VDZ and helps us determine its position on the treatment algorithm.

OP0264-HPR PERSPECTIVES ON APPROACHES TO PREDICT THE DEVELOPMENT OF RHEUMATOID ARTHRITIS: A QUANTITATIVE ASSESSMENT OF PATIENTS AND THEIR FIRST DEGREE RELATIVES

Background:

There is considerable interest within the medical research community in the identification of individuals at risk of developing rheumatoid arthritis (RA), to identify those who may benefit from preventive interventions. However, it is important to understand the views of those who may be candidates for such predictive tests, to inform the development of effective approaches. First degree relatives (FDRs) of patients with RA are at an increased risk of developing RA. RA patients can provide access to FDRs. Qualitative investigations have explored the views of these groups about predictive testing for RA1,2, but quantitative approaches are needed to develop a robust understanding.

Objectives:

To identify predictors of interest in predictive testing for FDRs and patients, and to assess the likelihood of patients communicating information about RA risk to their FDRs.

Methods:

Surveys were completed by 482 RA patients and 397 of their FDRs. Patients were invited to complete the survey and to provide another to their relatives. Spearman’s Rank Correlations were used to assess relationships between interest in predictive testing/ likelihood of risk communication and potential predictor variables.

Results:

FDRs had a median age of 41 years, 64% were female. 57% were definitely interested and 36% were probably interested in taking a predictive test for RA. Several predictors were found to be associated with interest (table 1).

Table 1.

Spearman’s correlations for relatives’ and patients’ interest in predictive testing. After applying a Bonferonni adjustment, p values were taken as statistically significant at p≤0.003.

FDRsPatientsPredictors of interest in predictive testingrsPrsPBrief Illness Perception Questionnaire0.110.030.090.05 Consequences0.16*0.002*0.100.03 Timeline0.090.07-0.050.28 Personal control-0.030.59-0.020.68 Treatment control-0.020.760.020.74 Identity0.090.090.120.01 Concern0.21*<0.001*0.16*<0.001* Coherence0.110.030.0070.88 Emotional0.120.020.110.02Information Seeking0.35*<0.001*0.22*<0.001*Decision making-0.050.330.070.13Health literacy0.030.520.020.62Health numeracy-0.060.23-0.020.72Brief Avoidance Coping Questionnaire0.120.02-0.010.76Optimism0.060.26-0.070.12Health anxiety0.16*0.001*--Perceived risk0.37*<0.001*--Rheumatoid Arthritis Impact of Disease--0.050.31

– not applicable

Patients had a median age of 65 years, 71% were female. 47% were definitely interested and 30% were probably interested in their children taking a predictive test. Several predictors were found to be associated with interest (table 1). On a Likert scale from extremely unlikely (0) to extremely likely (4), most patients indicated that they were likely to communicate RA risk information to their children (median score=3).

Conclusion:

Interest in predictive testing for RA was high amongst FDRs, and factors including information seeking preference, RA risk perception, concern about RA, perceived consequences of RA and health anxiety were significantly associated with interest. Patients were also willing to communicate information about RA risk to their children. These findings increase understanding of perceptual variation in those at risk of RA, and will inform the development of information to support decision making in individuals considering predictive tests and preventive interventions. We are currently extending this preliminary analysis by building multivariate models incorporating a range of attitudes about predictive testing, assessing predictors of patients’ likelihood of communicating to their FDRs about risk, and the relationship between patients’ and FDRs’ responses.

References:

[1]Stack RJ et al. BMJ open. 2016; 6(6):e010555.

[2]Falahee M et al. Arthritis care & research. 2017; 69(10):1558-65.

Acknowledgments:

This work was supported by Versus Arthritis; Grant reference: 21560.

Disclosure of Interests:

Imogen Wells: None declared, Gwenda Simons: None declared, Rebecca Stack: None declared, Christian Mallen Grant/research support from: My department has received financial grants from BMS for a cardiology trial., Peter Nightingale: None declared, Karim Raza Grant/research support from: KR has received research funding from AbbVie and Pfizer, Consultant of: KR has received honoraria and/or consultancy fees from AbbVie, Sanofi, Lilly, Bristol-Myers Squibb, UCB, Pfizer, Janssen and Roche Chugai, Speakers bureau: KR has received honoraria and/or consultancy fees from AbbVie, Sanofi, Lilly, Bristol-Myers Squibb, UCB, Pfizer, Janssen and Roche Chugai, M. Falahee: None declared

Predicting pathology on small bowel capsule endoscopy: a good FIT

Background and study aims  Small bowel capsule endoscopy [SBCE) has an established role in investigating suspected small bowel bleeding [SSBB). Identification of a biomarker to predict pathology would maximize utility of this valuable diagnostic modality. This study aimed to investigate if fecal immunochemical test [FIT) could predict likelihood of small bowel pathology on SBCE. Patients and methods  Patients referred for SBCE to investigate anaemia or suspected small bowel bleeding were prospectively recruited. All patients had negative upper and lower endoscopy prior to referral. A FIT ≥ 45 ug Hb/g was considered positive. SBCE was positive if a potential source of SSBB was identified. The primary endpoint was correlation between FIT and positive SBCE. Secondary endpoints were correlation between anemia and SBCE and a combination of anemia plus FIT and SBCE. Results  Fifty-one patients were included in the final study cohort. 29.4 % had a positive FIT, 33.3 % were anemic, and 25.5 % patients had significant SBCE findings. There was a statistically significant association between positive FIT and pathology on SBCE (OR 12, 95 % CI [2.8 - 51.9), P  = 0.001). Sensitivity and specificity of positive FIT in predicting SBCE findings were 69 % and 84 %, respectively. A normal Hb had an NPV of 83 % (OR 0.30, P  = 0.09). Combining Hb and FIT was statistically significant in predicting pathology on SBCE (OR 9.14, 67 % PPV, 82 % NPV, P  = 0.025). Conclusion  FIT ≥ 45 ug Hb/g is a useful tool in predicting small bowel pathology on SBCE. Use of this biomarker alone, or in combination with serum haemoglobin, has value as a screening tool and may help to better triage patients referred for SBCE.

Same-day colon capsule endoscopy is a viable means to assess unexplored colonic segments after incomplete colonoscopy in selected patients

Background

Same-day colon capsule endoscopy (CCE) immediately following incomplete optical colonoscopy (OC) would have a number of advantages for patients, while also presenting unique procedural challenges including the effect of sedation on capsule propulsion and patient tolerance of protracted preparation and fasting.

Aim

The aim of this article is to prospectively assess the efficacy of same-day CCE after incomplete OC in an unselected patient cohort.

Methods

This was an observational, prospective, single-centre study of CCE post-incomplete colonoscopies. Patients with an incomplete OC for any reason other than obstruction or inadequate bowel preparation were recruited. CCE was performed after a minimum of a one-hour fast. Once the patient was fully alert, intravenous metoclopramide was administered after capsule ingestion when possible, and a standard CCE booster protocol was then followed. Relevant clinical information was recorded. CCE completion rates, findings and their impact, and adverse events were noted.

Results

Fifty patients were recruited, mean age = 57 years and 66% (n = 32) were female. Seventy-six per cent (n = 38) of CCEs were complete; however, full colonic views were obtained in 84% (n = 42) of cases. Patients > 50 years of age were five times more likely to have an incomplete CCE and there was also a trend towards known comorbidities associated with hypomobility having reduced excretion rates. Overall diagnostic yield for CCE in the unexplored segments was 74% (n = 37), with 26% (n = 13) of patients requiring significant changes in management based on CCE findings. The overall incremental yield was 38%. CCE findings were normal 26% (n = 13), polyps 38% (n = 19), inflammation 22% (n = 11), diverticular disease 25 (n = 12), angiodysplasia 3% (n = 1) and cancer 3% (n = 1). Significant small bowel findings were found in three (6%) cases, including Crohn's disease and a neuroendocrine tumour. A major adverse event occurred in one patient (2%), related to capsule retention.

Conclusion

Same-day CCE is a viable alternative means to assess unexplored segments of the colon after incomplete OC in selected patients.

Clinical Outcome of Patients with Raised Intraepithelial Lymphocytes with Normal Villous Architecture on Duodenal Biopsy

INTRODUCTION

The finding of a raised intraepithelial lymphocytes (IELs) count with normal villous architecture is of sufficient clinical importance to be reported in routine duodenal biopsies.

AIM

To study the clinical and demographic data of patients with isolated increased IELs on duodenal biopsy.

METHODS

A single-tertiary-centre retrospective study was carried out with a review of medical records of patients with increased IELs. Patients from 2012 to 2014, >18 years with at least one biopsy from the second part of the duodenum with increased IELs; defined as >25 IELs/100 enterocytes, with preserved villous architecture were identified from our histopathology database with exclusion of patients with coeliac disease (CD).Clinical and demographic data were recorded following a chart review. CD was diagnosed by the attending physician based on the Physician Global Assessment. Data was compared between groups using a Student t test and ORs were calculated as appropriate. Statistical significance was set a priori at p < 0.05.

RESULTS

Over 24 months, 6,244 patients were found to have duodenal biopsies and 114 (1.8%) had isolated increased IELs. Of the patients with increased IELs, the mean age was 50 years and 34 (30%) were male. Follow-up was available in 75 (65%) of these and CD was subsequently diagnosed in 32% (n = 24). CD was associated with the female gender (22 out of 24 vs. 39 out of 51, OR 7.5, older age 55 vs. 41 years, p < 0.04), and higher IEL count with an IEL of >40 in 11 out of 24 (46%) with CD vs. 12 out of 51 (24%) without CD, p = 0.0006.

CONCLUSION

It is a non-specific but important finding, as it can have clinical implications.

Post-ERCP Emphysematous Cholecystitis in a Young Woman: A Rare and Potentially Fatal Complication

A 45-year-old woman with suspected Functional Biliary Sphincter Disorder (FBSD) developed Clostridium perfringens related emphysematous cholecystitis after ERCP. A low index of suspicion for emphysematous cholecystitis in this young, otherwise healthy woman led to a significant delay in making the correct diagnosis, and air in the gallbladder was wrongly attributed to a possible gallbladder perforation. ERCP is associated with significant risks, particularly in patients with FBSD, where diagnostic uncertainty renders the balance of risk versus benefit even more critical. Post-ERCP emphysematous cholecystitis secondary to Clostridium perfringens is a rare but potentially fatal complication.

MDM2 overexpression in benign and malignant lesions of the human breast

MDM2 overexpression has been detected in women with benign or cancerous lesions of the breast. Immunohistochemical methods were used to identify overexpression in 11 of 27 benign cases (41%) and 15 of 22 (68%) cancer cases. MDM2 overexpression correlated well with immunohistochemically detected estrogen receptor (ER), suggesting that expression of these proteins was coordinately regulated. To test this, the MCF-10A human breast cell line, negative for both ER and MDM2 expression, was transfected with a wild-type ER. Following transfection, both ER and MDM2 were strongly expressed in two independent clones. Expression of both was reduced in the presence of increasing concentrations of estradiol (10(-10)-10(-8) M) thus, estrogen may be involved in regulation of MDM2 expression in proliferative breast lesions.

Regulation of T lymphocyte subsets

Patterns of cytokine secretion and functional differences distinguish T lymphocyte subsets. T lymphocyte subsets are also regulated differentially. Most established CD8+ lymphocyte clones secrete gamma-interferon (IFN-gamma) but not interleukin 2 (IL-2) or IL-4. Using murine T cells which express a transgenic, antigen-specific alpha/beta T cell receptor (TCR) specific for L(d) class I major histocompatibility complex antigen, we have found that CD8+ lymphocytes can be divided into functional subsets. Freshly isolated CD8+ T cells are not cytolytic, do not proliferate and do not proliferate and do not secrete cytokines. Stimulation of TCR alone does not induce cytokine secretion, but cells become responsive to exogenous IL-2 or IL-4. Stimulation of CD28 together with TCR induces secretion of IL-2 and IFN-gamma, and cells proliferate without exogenous cytokines. Proliferation is necessary for the development of cytolytic activity. If IL-4 is present during initial stimulation, IL-4 is secreted following restimulation. Upon stimulation, some IL-4-producing murine CD8+ T cell clones express CD40 ligand (CD40L), and they potentiate proliferation and immunoglobulin secretion by small resting B cells. Thus, the CD8+ T cell subsets T cytotoxic 1 (Tc1) and Tc2 are analogous to CD4+ T helper 1 (Th1) and Th2. IL-2 production by naive CD8+ cells requires co-stimulation. IL-4 production by CD8+ T cells requires the presence of IL-4 during initial stimulation. Some IL-4-producing CD8+ T cells express CD40L following TCR stimulation and provide help for B cells.

An evaluation of the performance of cDNA microarrays for detecting changes in global mRNA expression

The cDNA microarray is one technological approach that has the potential to accurately measure changes in global mRNA expression levels. We report an assessment of an optimized cDNA microarray platform to generate accurate, precise and reliable data consistent with the objective of using microarrays as an acquisition platform to populate gene expression databases. The study design consisted of two independent evaluations with 70 arrays from two different manufactured lots and used three human tissue sources as samples: placenta, brain and heart. Overall signal response was linear over three orders of magnitude and the sensitivity for any element was estimated to be 2 pg mRNA. The calculated coefficient of variation for differential expression for all non-differentiated elements was 12-14% across the entire signal range and did not vary with array batch or tissue source. The minimum detectable fold change for differential expression was 1.4. Accuracy, in terms of bias (observed minus expected differential expression ratio), was less than 1 part in 10 000 for all non-differentiated elements. The results presented in this report demonstrate the reproducible performance of the cDNA microarray technology platform and the methods provide a useful framework for evaluating other technologies that monitor changes in global mRNA expression.

Cone-beam tomography with a digital camera

We show that x-ray computer tomography algorithms can be applied with minimal alteration to the three-dimensional reconstruction of visible sources. Diffraction and opacity affect visible systems more severely than x-ray systems. For camera-based tomography, diffraction can be neglected for objects within the depth of field. We show that, for convex objects, opacity has the effect of windowing the angular observation range and thus blurring the reconstruction. For concave objects, opacity leads to nonlinearity in the transformation from object to reconstruction and may cause multiple objects to map to the same reconstruction. In x-ray tomography, the contribution of an object point to a line integral is independent of the orientation of the line. In optical tomography, however, a Lambertian assumption may be more realistic. We derive an expression for the blur function (the patch response) for a Lambertian source. We present experimental results showing cone-beam reconstruction of an incoherently illuminated opaque object.

Use of the perfusion balloon as a primary dilation device

The development of more user-friendly and versatile perfusion balloon catheters has increased the use of prolonged dilations as a primary catheter treatment for coronary artery disease. In a multicenter randomized trial, the use of these devices to prolong initial inflation durations resulted in improved angiographic outcomes when compared with conventional short dilations. This benefit was most apparent in stenoses with complex morphology. Use of the perfusion balloon as a primary device is also appealing because of its ability to reduce anginal pain and hemodynamic changes during balloon inflation. Clinical experience suggests that primary use of the perfusion balloon may improve patient stability during procedures in which the treated segment jeopardizes a large percentage of the functional myocardium. An observational series has demonstrated the excellent outcomes which can be achieved in selected patients using a strategy of primary perfusion angioplasty with stent bailout when needed. Selection of a perfusion balloon rather than a conventional balloon as a primary device has the potential to decrease overall balloon usage approximately 25%, but the economic benefit of this strategy will depend on the cost of the perfusion balloon relative to a conventional balloon. Retrospective analyses suggest that perfusion angioplasty as a primary treatment strategy compares favorably with directional atherectomy for left anterior descending lesions. The use of coronary stents has not been directly compared to perfusion angioplasty as a primary treatment for coronary lesions, but use of a perfusion balloon as an initial device may have broader applicability, lower cost and less technical demands on the operator compared to stent deployment. In conclusion, when overall applicability, clinical outcome and cost are considered, the primary strategy of prolonged dilation with a perfusion balloon should have an important role in coronary intervention.

Tomographic imaging of foam

The morphology of three-dimensional foams is of interest to physicists, engineers, and mathematicians. It is desired to image the 3-dimensional structure of the foam. Many different techniques have been used to image the foam, including magnetic resonance imaging, and short-focal length lenses. We use a camera and apply tomographic algorithms to accurately image a set of bubbles. We correct for the distortion of a curved plexiglas container using ray-tracing.

Survival in renal vascular disease

Renal artery stenosis (RAS) is a relatively uncommon but important potentially reversible cause of renal failure. Little is known about the natural history of ischemic renal disease secondary to RAS. In previous reports, these researchers examined the incidence and risk factors associated with RAS. The study presented here investigates the long-term follow-up of these patients, specifically the effect of RAS on 4-yr, all-cause mortality in a group of 1235 patients undergoing diagnostic cardiac catheterization and abdominal aortography. A total of 1235 consecutive patients undergoing cardiac catheterization also underwent an abdominal flush aortogram. Significant RAS was considered present if one or more renal artery had 50% or greater narrowing in luminal diameter. Four-year unadjusted survival for patients with RAS was 65% compared with 86% for patients undergoing catheterization without significant RAS. Factors associated with decreased 4-yr survival included increased age, increased serum creatinine, presence of RAS, peripheral vascular disease, congestive heart failure, diabetes, hypertension, and reduced ejection fraction. Using the Cox proportional hazards model, the factors associated with decreased 4-yr survival were the presence of significant RAS, reduced ejection fraction, elevated serum creatinine, and symptoms of congestive heart failure. These observations indicate that the presence of significant RAS is a strong independent predictor of 4-yr survival in this patient population.

IL-4-producing CD8+ T cell clones can provide B cell help

Interactions between CD4+ T cells and B cells are mediated by both soluble factors and cell surface molecules. The Ag-independent interaction between the CD40 ligand, expressed on activated T cells, and its CD40 receptor, expressed on B cells, enhances B cell proliferation in response to IL-4 stimulation. The expression of the CD40 ligand is induced on CD4+ T cells by stimulation with Ag-pulsed APC or mitogens. Here, we show that at least some IL-4-producing murine CD8+ T cell clones can be induced to express the CD40 ligand when stimulated with anti-CD3 mAb. Additionally, such activated CD8+ IL-4-producing clones potentiate the proliferative response of small resting B cells to IL-4 and induce Ig secretion by small resting B cells to IL-4 and IL-5. Proliferation of small resting B cells cultured with IL-4 in the presence of activated IL-4-producing CD8+ murine T cell clones appeared to be mediated by the expression of the CD40 ligand on the T cell because an anti-CD40 ligand mAb inhibited this proliferative response. A conventional murine CD8+ CTL clone, which did not produce IL-4 or express CD40 ligand upon activation, did not potentiate proliferation of small resting B cells exposed to IL-4. Thus, under some circumstances, CD8+ T cells that are able to express CD40 ligand may be able to provide B cell help.

IL-4-producing CD8+ T cell clones can provide B cell help

Interactions between CD4+ T cells and B cells are mediated by both soluble factors and cell surface molecules. The Ag-independent interaction between the CD40 ligand, expressed on activated T cells, and its CD40 receptor, expressed on B cells, enhances B cell proliferation in response to IL-4 stimulation. The expression of the CD40 ligand is induced on CD4+ T cells by stimulation with Ag-pulsed APC or mitogens. Here, we show that at least some IL-4-producing murine CD8+ T cell clones can be induced to express the CD40 ligand when stimulated with anti-CD3 mAb. Additionally, such activated CD8+ IL-4-producing clones potentiate the proliferative response of small resting B cells to IL-4 and induce Ig secretion by small resting B cells to IL-4 and IL-5. Proliferation of small resting B cells cultured with IL-4 in the presence of activated IL-4-producing CD8+ murine T cell clones appeared to be mediated by the expression of the CD40 ligand on the T cell because an anti-CD40 ligand mAb inhibited this proliferative response. A conventional murine CD8+ CTL clone, which did not produce IL-4 or express CD40 ligand upon activation, did not potentiate proliferation of small resting B cells exposed to IL-4. Thus, under some circumstances, CD8+ T cells that are able to express CD40 ligand may be able to provide B cell help.

"Anergy" of TH0 helper T lymphocytes induces downregulation of TH1 characteristics and a transition to a TH2-like phenotype

Mature CD4+ helper T lymphocytes have been categorized into two major functional phenotypes, TH1 and TH2, which produce distinct arrays of lymphokines and which are thought to arise from a pluripotential precursor cell termed TH0. Clonal anergy can be induced in TH1 clones by stimulating via the T cell receptor (TCR) complex in the absence of a costimulator molecule; however, anergy has been difficult to demonstrate in TH2 clones. We show here that treatment of cloned TH0 lines with anergizing stimuli results in the selective loss of TH1 characteristics and retention of a TH2 phenotype. Treated cells exhibit a substantial reduction in interleukin 2 (IL-2) production and antigen-specific cytolytic activity, but retain comparable IL-4 and IL-5 production in response to restimulation via the TCR complex. TH0 clones exposed to anergizing stimuli also increase in size, thus morphologically resembling TH2 cells. The signaling characteristics of these cells also are altered, in that they exhibit an elevated basal level of intracellular free calcium which fails to increase significantly with subsequent restimulation, reminiscent of the signaling characteristics of TH2 cells. "Anergized" TH0 clones thus share several functional, morphologic, and physiologic properties with cells of the TH2 phenotype, suggesting that TH2 cells may arise when TH0 cells are stimulated via the TCR complex in the absence of a putative costimulator molecule.

Myocardial perfusion and ventricular function measurements during total coronary artery occlusion in humans. A comparison with rest and exercise radionuclide studies

BACKGROUND

The purpose of this investigation was to compare the magnitude of change in myocardial perfusion and function during exercise with that obtained during total coronary artery occlusion. Radionuclide studies are widely used for the diagnosis and determination of prognosis in patients with suspected or known coronary artery disease. These studies are based on the premise that the relative deficit of coronary blood flow, which is induced by exercise and recognized as increased demand, relates to the jeopardy experienced by the decrease or sudden absolute interruption of coronary blood flow that is recognized as decreased supply and is associated with coronary stenosis or total coronary artery occlusion. The magnitude of exercise-induced perfusion and function abnormalities compared with those induced by total coronary artery occlusion in humans has not been previously reported.

METHODS AND RESULTS

We prospectively studied 20 patients with > or = 50% diameter stenosis documented by quantitative coronary angiography in at least one vessel. A same-day rest/exercise sestamibi myocardial function and perfusion study was performed within 24 hours before percutaneous transluminal coronary angioplasty. At 1 minute after balloon inflation, while the vessel was occluded, sestamibi was injected, and a myocardial perfusion and function study was performed. Perfusion defect size was greater during occlusion (28 +/- 3%) than during exercise (13 +/- 2%) (P < .01). Ejection fraction was greater during exercise (53 +/- 3%) compared with values measured during occlusion (41 +/- 2%) (P < .01).

CONCLUSIONS

Physiological abnormalities induced by coronary occlusion are greater than those that occur during exercise, thereby indicating that stress-induced ischemia may not reflect the total potential myocardium in jeopardy from a stenotic lesion, if sudden occlusion occurs.

Direct vision internal urethrotomy using topical anesthesia

A consecutive series of 18 patients underwent attempted direct vision internal urethrotomy (DVIU) under topical lidocaine anesthesia. The procedure was completed successfully in 15 of 18 (83%) patients. In these patients 12 of 15 (80%) reported either minimal or no discomfort. Direct vision internal urethrotomy using topical lidocaine anesthesia is a safe and cost effective procedure.

"Hugging balloons" through a single 8-French guide: salvage angioplasty with lytic therapy in the infarct vessel of a 40-year-old man

We report the a case of hugging balloons through an 8-French guiding catheter to stabilize an ectatic right coronary artery following failed thrombolytic therapy in the setting of acute myocardial infarction. Angiographic follow-up at 1 wk and 6 mo revealed persistent vessel patency.

Coronary bypass surgery improves global and regional left ventricular function following thrombolytic therapy for acute myocardial infarction. TAMI Study Group

Coronary bypass surgery was performed prior to hospital discharge in 303 (22%) of 1387 consecutive patients enrolled in the TAMI 1 to 3 and 5 trials of intravenous thrombolytic therapy for acute myocardial infarction. Bypass surgery was of emergency nature (less than 24 hours from treatment with intravenous thrombolytic therapy) in 36 (2.6%) and was deferred (greater than 24 hours) in 267 (19.3%) patients. The indications for bypass surgery included failed angioplasty (12%); left main or equivalent coronary disease (9%); complex or multivessel coronary disease (62%); recurrent postinfarction angina (13%); and refractory pump dysfunction, mitral regurgitation, ventricular septal rupture or abnormal predischarge functional test (1% each). Although patients having bypass surgery were older (59.5 +/- 9.8 versus 56.0 +/- 10.2 years, (p less than 0.0001), had more extensive coronary artery disease (46% with three-vessel disease versus 11%, (p less than 0.0001), had more frequent diabetes mellitus (19% versus 15%, (p = 0.048), had more prior infarctions (p less than 0.0001), had more severe initial depression in global left ventricular ejection fraction (48.0 +/- 11.9% versus 51.8 +/- 11.9%, p = 0.0002), and regional infarct zone (-2.7 +/- 0.94 versus -2.5 +/- 1.1 SD/chord, p = 0.02) and noninfarct zone function (-0.36 +/- 1.8 versus 0.43 +/- 1.6 SD/chord, p less than 0.0001) than patients not having coronary bypass surgery, no difference in the incidence of death in hospital (7% surgical versus 6% nonsurgical) or death at long-term follow-up of hospital survivors (7% surgical versus 6% nonsurgical) was noted between groups. Surgical patients demonstrated a greater degree of recovery in left ventricular ejection fraction (3.4 +/- 9.8% versus 0.16 +/- 8.5%, p = 0.036) and infarct zone regional function (0.71 +/- 1.1 versus 0.34 +/- 0.99 SD/chord, p = 0.001) when immediate (90 minutes following initiation of thrombolytic therapy) and predischarge (7 to 14 days after treatment) contrast left ventriculograms were compared than did patients who received only intravenous thrombolytic therapy with or without coronary angioplasty. These data suggest a beneficial influence of coronary bypass surgery on left ventricular function and possibly on the clinical outcome of patients initially treated with intravenous thrombolytic therapy for acute myocardial infarction.

A piece-wise non-linear elastic stress expression of human and pig coronary arteries tested in vitro

Eight human and nineteen pig unembalmed proximal left anterior descending and circumflex coronary arteries were subjected to linear volume changes (2 s ramp time) at three fixed axial extensions while immersed in a physiological saline bath at body temperature. Measured parameters included: lumen pressure, outside diameter, axial force, and axial extension. The deformations were measured using a video dimensional analyzer. The arteries were inflated to pressures well above the physiological range at each axial extension. A latex inner tube was placed inside of each specimen to prevent leakage, and its effects upon the measured stresses were corrected analytically. With this method, the average circumferential and axial stresses could be computed directly from the experimental data. In both directions the average stresses measured displayed two distinct regions: stresses occurring for small diameter changes (physiological pressures) and stresses occurring for large diameter changes (high pressures). The resulting average small strain and large strain stress components were curve-fit separately and, when reassembled, provided a piece-wise model of the stress response of coronary arteries over a wide range of inflation pressures and axial extensions.

Consequences of reocclusion after successful reperfusion therapy in acute myocardial infarction. TAMI Study Group

To determine the clinical consequences of reocclusion of an infarct-related artery after reperfusion therapy, we evaluated 810 patients with acute myocardial infarction. Patients were admitted into four sequential studies with similar entry criteria in which patency of the infarct-related artery was assessed by coronary arteriography 90 minutes after onset of thrombolytic therapy. Successful reperfusion was established acutely in 733 patients. Thrombolytic therapy included tissue-type plasminogen activator (t-PA) in 517, urokinase in 87, and a combination of t-PA and urokinase in 129 patients. All patients received aspirin, intravenous heparin and nitroglycerin, and diltiazem during the recovery phase. A repeat coronary arteriogram was performed in 88% of patients at a median of 7 days after the onset of symptoms. Reocclusion of the infarct-related artery occurred in 91 patients (12.4%), and 58% of these were symptomatic. Angiographic characteristics at 90 minutes after thrombolytic therapy that were associated with reocclusion compared with sustained coronary artery patency were right coronary infarct-related artery (65% versus 44%, respectively) and Thrombolysis in Myocardial Infarction (TIMI) flow 0 or 1 (21% versus 10%, respectively) before further intervention. Median (interquartile value) degree of stenosis in the infarct-related artery at 90 minutes was similar between groups: 99% for reoccluded (value, 90/100%) compared with 95% for patent (value, 80/99%). Patients with reocclusion had similar left ventricular ejection fractions compared with patients with sustained patency at follow-up. However, patients with reocclusion at follow-up had worse infarct-zone function at -2.7 (value, -3.2/-1.8) versus -2.4 (SD/chord) (value, -3.1/-1.3) (p = 0.016). The recovery of both global and infarct-zone function was impaired by reocclusion of the infarct-related artery compared with maintained patency; median delta ejection fraction was -2 compared with 1 (p = 0.006) and median delta infarct-zone wall motion was -0.10 compared with 0.34 SD/chord (p = 0.011), respectively. In addition, patients with reocclusion had more complicated hospital courses and higher in-hospital mortality rates (11.0% versus 4.5%, respectively; p = 0.01). We conclude that reocclusion of the infarct-related artery after successful reperfusion is associated with substantial morbidity and mortality rates. Reocclusion is also detrimental to the functional recovery of both global and infarct-zone regional left ventricular function. Thus, new strategies in the postinfarction period need to be developed to prevent reocclusion of the infarct-related artery.

Histopathologic examination of material from angioplasty balloon catheters used in vivo in human coronary arteries

Reports on vascular pathology post-PTCA in both human and animal coronary vessels have revealed medial and intimal cracks and tears, thrombus formation, platelet accumulation, and loss of endothelial cells. The extent and type of damage can currently be assessed in vivo at the macro level by means of coronary artery angiography. However, this technique cannot define vessel wall characteristics at the cellular level. Our hypothesis is that vessel wall material may adhere to the balloon and thus provide a source for coronary artery cytological investigation in vivo. Ten balloon catheters were evaluated to discern any material which was dislodged from the coronary artery and which remained attached to the balloon catheter or guide wire. Our results indicate that angioplasty catheter balloons frequently have adherent collagen, endothelial cells, organized thrombus, and plaque with obvious cholesterol clefts, that can be retrieved and examined histologically. We conclude that material is often dislodged from the plaque during PTCA. In addition, plaque material removed by the balloon catheter offers an unusual opportunity to analyze the morphologic characteristics of cells from the human coronary artery in vivo.

An acyl-thioesterase from yeast mitochondria

A previously unstudied acyl-coenzyme A thioesterase activity has been demonstrated in submitochondrial particles from Saccharomyces cerevisiae. The preferred substrate for the enzyme activity is oleoyl-coenzyme A. Tests with inhibitors of the thioesterase showed that, in addition to common thiol inhibitors, the oxidative phosphorylation inhibitors oligomycin and venturicidin also blocked thioesterase activity. Purification of the enzyme catalyzing this activity revealed that thioesterase copurified with mitochondrial ATPase. When thioesterase was isolated from oxidative phosphorylation mutants selected for resistance to these two inhibitors, thioesterase activity was also resistant. The results suggest that thioester hydrolysis may be catalyzed by components associated with the isolated ATPase complex. Further attempts to link this activity to in vivo function of ATPase were not successful.

Evaluation of the left ventricle with two dimensional echocardiography

Two dimensional echocardiography, because of its wide field of view, has been shown to be superior to the M mode approach for ultrasonic evaluation of the left ventricle. The use of this technique for determination of ventricular volume estimates and detection of asynergy has been promising but is limited by compromised image quality found in many patients with ischemic heart disease. Because it supplies cross-sectional information about the ventricular chamber and wall thickness simultaneously, this new technique lends itself to the anatomic localization of changes in regional performance that accompany ischemic heart disease. It allows simultaneous study of regional dynamic changes in chamber circumference, wall thickness and motion characteristics that give practical information on coronary artery disease and acute myocardial infarction.