Marginal cost per QALY estimates: What are they good for?

Estimates of the marginal cost per quality-adjusted life year (MCPQ) are available for health care systems worldwide. Researchers routinely make claims about these estimates and how they should inform policymaking. This commentary considers these claims by taking a recent article from Health Policy as a case study. Claims are made about the past performance of the health service and about future decisions and relate to such considerations as productivity, the impact of technology approvals, cost-effectiveness thresholds, and budget allocation. We argue that the evidence does not justify these claims and MCPQ estimates should instead inform questions about the consequences of changes in expenditure.

Logical Inconsistencies in the Health Years in Total and Equal Value of Life-Years Gained

OBJECTIVES

This study aimed to assess whether recently proposed alternatives to the quality-adjusted life-year (QALY), intended to address concerns about discrimination, are suitable for informing resource allocation decisions.

METHODS

We consider 2 alternatives to the QALY: the health years in total (HYT), recently proposed by Basu et al, and the equal value of life-years gained (evLYG), currently used by the Institute for Clinical and Economic Review. For completeness we also consider unweighted life-years (LYs). Using a hypothetical example comparing 3 mutually exclusive treatment options, we consider how calculations are performed under each approach and whether the resulting rankings are logically consistent. We also explore some further challenges that arise from the unique properties of the HYT approach.

RESULTS

The HYT and evLYG approaches can result in logical inconsistencies that do not arise under the QALY or LY approaches. HYT can violate the independence of irrelevant alternatives axiom, whereas the evLYG can produce an unstable ranking of treatment options. HYT have additional issues, including an implausible assumption that the utilities associated with health-related quality of life and LYs are "separable," and a consideration of "counterfactual" health-related quality of life for patients who are dead.

CONCLUSIONS

The HYT and evLYG approaches can result in logically inconsistent decisions. We recommend that decision makers avoid these approaches and that the logical consistency of any approaches proposed in future be thoroughly explored before considering their use in practice.

This Dead or That Dead: Framing Effects in the Evaluation of Health States

OBJECTIVES

Current approaches to health state valuation rely on credible classification of states as either "better than dead" or "worse than dead" (WTD). We investigate how such evaluations of health states are affected by the framing in pairwise comparison tasks.

METHODS

We conducted an online survey with 361 participants to compare the propensity to evaluate a state as WTD under 6 frames: (A) using a regular time trade-off (TTO) choice task, (B) using a lead-time TTO choice task, (C) excluding the immediacy of death, (D) avoiding reference to the process of dying, (E) focusing on longevity, and (F) focusing on improvements in quality of life. Each participant evaluated 9 EQ-5D-5L health states using 3 frames. The frames were compared using several statistical approaches to confirm robustness to indirect comparisons or respondent heterogeneity and inattentiveness.

RESULTS

The odds of a state being evaluated as WTD, compared with frame A, increase 2.7-fold and 1.5-fold in frame B and E, respectively, and decrease >5-fold in frame F. Frames C and D do not differ significantly from frame A.

CONCLUSIONS

Different framings for questions about whether a state is WTD or better than dead, even if theoretically equivalent, yield substantially different results. Notably, whether a state is evaluated as WTD differs greatly between the regular TTO and lead-time TTO choice tasks and when either final outcomes or improvements over time are considered.

Supply-Side Cost-Effectiveness Thresholds: Questions for Evidence-Based Policy

There is growing interest in cost-effectiveness thresholds as a tool to inform resource allocation decisions in health care. Studies from several countries have sought to estimate health system opportunity costs, which supply-side cost-effectiveness thresholds are intended to represent. In this paper, we consider the role of empirical estimates of supply-side thresholds in policy-making. Recent studies estimate the cost per unit of health based on average displacement or outcome elasticity. We distinguish the types of point estimates reported in empirical work, including marginal productivity, average displacement, and outcome elasticity. Using this classification, we summarise the limitations of current approaches to threshold estimation in terms of theory, methods, and data. We highlight the questions that arise from alternative interpretations of thresholds and provide recommendations to policymakers seeking to use a supply-side threshold where the evidence base is emerging or incomplete. We recommend that: (1) policymakers must clearly define the scope of the application of a threshold, and the theoretical basis for empirical estimates should be consistent with that scope; (2) a process for the assessment of new evidence and for determining changes in the threshold to be applied in policy-making should be created; (3) decision-making processes should retain flexibility in the application of a threshold; and (4) policymakers should provide support for decision-makers relating to the use of thresholds and the implementation of decisions stemming from their application.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

How symmetry-breaking can amplify the magnetosensitivity of dipolarly coupled n-radical systems

In systems of more than two reactive radicals, the radical recombination probability can be magnetosensitive due to the mere effect of the inter-radical electron-electron dipolar coupling. Here, we demonstrate that this principle, previously established for three-radical systems, generalizes to n-radical systems. We focus on radical systems in the plane and explore the effects of symmetry, in particular its absence, on the associated magnetic field effects of the recombination yield. We show, by considering regular configurations and slightly distorted geometries, that the breaking of geometric symmetry can lead to an enhancement of the magnetosensitivity of these structures. Furthermore, we demonstrate the presence of effects at low-field that are abolished in the highly symmetric case. This could be important to the understanding of the behavior of radicals in biological environments in the presence of weak magnetic fields comparable to the Earth's, as well as the construction of high-precision quantum sensing devices.

On the magnetosensitivity of lipid peroxidation: two- versus three-radical dynamics

We present a theoretical analysis of the putative magnetosensitivity of lipid peroxidation. We focus on the widely accepted radical pair mechanism (RPM) and a recently suggested idea based on spin dynamics induced in three-radical systems by the mutual electron-electron dipolar coupling (D3M). We show that, contrary to claims in the literature, lipid peroxides, the dominant chain carriers of the autoxidation process, have associated non-zero hyperfine coupling interactions. This suggests that their recombination could, in principle, be magnetosensitive due to the RPM. While the RPM indeed goes a long way to explaining magnetosensitivity in these systems, we show that the simultaneous interaction of three peroxyl radicals via the D3M can achieve larger magnetic field effects (MFE), even if the third radical is remote from the recombining radical pair. For randomly oriented three-radical systems, the D3M induces a low-field effect comparable to that of the RPM. The mechanism furthermore immunizes the spin dynamics to the presence of large exchange coupling interactions in the recombining radical pair, thereby permitting much larger MFE at magnetic field intensities comparable to the geomagnetic field than would be expected for the RPM. Based on these characteristics, we suggest that the D3M could be particularly relevant for MFE at low fields, provided that the local radical concentration is sufficient to allow for three-spin radical correlations. Eventually, our observations suggest that MFEs could intricately depend on radical concentration and larger effects could ensue under conditions of oxidative stress.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

A "Stepping Stone" Approach for Obtaining Quantum Free Energies of Hydration

We present a method which uses DFT (quantum, QM) calculations to improve free energies of binding computed with classical force fields (classical, MM). To overcome the incomplete overlap of configurational spaces between MM and QM, we use a hybrid Monte Carlo approach to generate quickly correct ensembles of structures of intermediate states between a MM and a QM/MM description, hence taking into account a great fraction of the electronic polarization of the quantum system, while being able to use thermodynamic integration to compute the free energy of transition between the MM and QM/MM. Then, we perform a final transition from QM/MM to full QM using a one-step free energy perturbation approach. By using QM/MM as a stepping stone toward the full QM description, we find very small convergence errors (<1 kJ/mol) in the transition to full QM. We apply this method to compute hydration free energies, and we obtain consistent improvements over the MM values for all molecules we used in this study. This approach requires large-scale DFT calculations as the full QM systems involved the ligands and all waters in their simulation cells, so the linear-scaling DFT code ONETEP was used for these calculations.

Generic preference-based measures: how economists measure health benefit

Resources are always scarce, but the possible uses of these resources are limitless. This simple observation underlies much of what economists do. It leads to competing demands from different parties and requires individuals and organisations to make choices about their use of scarce resources. The primary purpose of economics is to help us understand how decisions about the distribution of scarce resources are made and to identify optimal decisions. It shouldn’t take too much of an intellectual leap to see how adopting an economist’s perspective might contribute to the improvement of patient care and health outcomes. The process of evaluating health care interventions is well-established, with the randomised controlled trial maintaining its place as the gold standard method. A crucial decision that must be made in figuring out if an intervention works is which indicator should be used. The purpose of the intervention might be to reduce mortality, improve functioning or prevent falls. It could be all three. If the intervention produces an improvement in these indicators it is probably of value – but of what value? How do we value this intervention? And why might we want to?

Foreign body impaction as presentation of eosinophilic esophagitis

Esophageal foreign body is a frequent pediatric presentation, and eosinophilic esophagitis (EoE) is an important underlying disease. To determine characteristics common in the presentation of esophageal foreign body indicative of underlying EoE and reach a recommendation for the appropriate scenario in which to obtain esophageal mucosal biopsy, 312 pediatric esophageal foreign bodies requiring operative removal were reviewed. Patients older than 18 years or with a known history of esophageal surgery or pathology were excluded. Eligibility criteria were met in 271 cases. Twenty-seven patients were biopsied, and 18 were diagnosed with EoE. The following factors were identified in the EoE population: food impaction (89%), older age (average 12.2 years), male sex (78%), atopic disease (61%), previous esophageal foreign body or frequent dysphagia (83%), and endoscopic abnormalities (100%). These factors are all associated with an underlying diagnosis of EoE, and patients meeting these criteria should be strongly considered for intraoperative esophageal mucosal biopsy.

Critical role of NMDA but not opioid receptors in the acquisition of fat-conditioned flavor preferences in rats

Animals learn to prefer flavors associated with the intake of dietary fats such as corn oil (CO) solutions. We previously reported that fat-conditioned flavor preferences in rats were relatively unaffected by systemic treatment with dopamine D1 and D2 antagonsits. The present study examined whether systemic opioid (naltrexone, NTX) or NMDA (MK-801) receptor antagonists altered the acquisition and/or expression of CO-CFP. The CFP was produced by training rats to drink one novel flavor (CS+, e.g., cherry) mixed in a 3.5% CO solution and another flavor (CS-, e.g., grape) in a 0.9% CO solution. In expression studies, food-restricted rats drank these solutions in one-bottle sessions (2 h) over 10 d. Subsequent two-bottle tests with the CS+ and CS- flavors mixed in 0.9% CO solutions occurred 0.5h after systemic administration of vehicle (VEH), NTX (0.1-5 mg/kg) or MK-801 (50-200 μg/kg). Rats displayed a robust CS+ preference following VEH treatment (85-88%) which was significantly though moderately attenuated by NTX (69-70%). The lower doses of MK-801 slightly reduced the CS+ preference; the high dose blocked the CS+ preference (49%) but also markedly reduced overall CS intake. In separate acquisition studies, rats received VEH or NTX (0.1, 0.5, 1mg/kg) or MK-801 (100 μg/kg) 0.5h prior to 1-bottle training trials with CS+/3.5% CO and CS-/0.9% CO training solutions. Additional Limited VEH groups were trained with intakes limited to that of the NTX and MK-801 groups. Subsequent two-bottle CS+ vs. CS- tests were conducted without injections. Significant and persistent CS+ preferences were observed in VEH (77-84%) and Limited VEH (88%) groups. NTX treatment during training failed to block the acquisition of CO-CFP although the magnitude of the CS+ preference was reduced by 0.5 (70%) and 1.0 (72%) mg/kg doses relative to the Limited VEH treatment (88%). In contrast, MK-801 (100 μg/kg) treatment during training blocked the acquisition of the CO-CFP. These data suggest a critical role for NMDA, but not opioid receptor signaling in the acquisition of a fat conditioned flavor preferences, and at best limited involvement of NMDA and opioid receptors in the expression of a previously learned preference.

Foreign Body as Initial Symptom of Eosinophilic Esophagitis

Objective: 1) Determine characteristics common in the presentation of esophageal foreign body that indicate presence of underlying esophageal pathology. 2) Provide clinical guidelines to consider esophageal mucosal biopsy during foreign body removal.

Method: Three hundred twelve cases of pediatric patients with an esophageal foreign body requiring esophagoscopy for removal were reviewed. Patients were excluded if a history of esophageal surgery or pathology was present. Factors common to those patients subsequently diagnosed with eosinophilic esophagitis (EE) were identified.

Results: Eligibility criteria were met in 271 cases. Of these, 27 underwent esophageal biopsy and 18 were diagnosed with EE. The following factors were compared between the EE population and the group as a whole: food impaction (89% of EE patients, 11% of non-EE patients), older age (average EE age 11.9, overall average age 4.5), atopic disease (61.1% of EE, 17.0% non-EE), abnormalities on esophagoscopy (94.4% of EE, 8.9% overall), and previous esophageal foreign body or frequent dysphagia (83.3% of EE, 5.9% non-EE). Eighteen percent of EE patients had 2 or more impactions requiring esophagoscopy prior to a biopsy being taken.

Conclusion: Older age, food impaction, history of atopic disease or previous esophageal foreign body, and abnormalities on esophagoscopy are all associated with EE. Patients meeting these criteria should be strongly considered for mucosal biopsy during foreign body removal. Failure to do so may lead to repeated foreign body events.

Roles of dopamine D1 and D2 receptors in the acquisition and expression of fat-conditioned flavor preferences in rats

Sugars and fats elicit innate and learned flavor preferences with the latter mediated by flavor-flavor (orosensory) and flavor-nutrient (post-ingestive) processes. Systemic dopamine (DA) D1 (SCH23390: SCH) and D2 (raclopride: RAC), but not opioid antagonists blocked the acquisition and expression of flavor-flavor preferences conditioned by sugars. In addition, systemic D1, but not D2 or opioid antagonists blocked the acquisition of flavor-nutrient preferences conditioned by intragastric (IG) sugar infusions. Given that DA antagonists reduce fat intake, the present study examined whether systemic D1 or D2 antagonists altered the acquisition and/or expression of conditioned flavor preferences (CFP) produced by pairing one novel flavor (CS+, e.g., cherry) with a 3.5% corn oil (CO: fat) solution relative to another flavor (CS-, e.g., grape) paired with a 0.9% CO solution. In an expression study, food-restricted rats were trained to drink either flavored 3.5% or 0.9% CO solutions on alternate days. Subsequent two-bottle tests with the CS+ and CS- flavors mixed in 0.9% CO solutions occurred 0.5h after systemic administration of vehicle (VEH), SCH (50-800 nmol/kg) or RAC (50-800 nmol/kg). The rats displayed a robust CS+ preference following VEH treatment (87-88%) the expression of which was attenuated by treatment with moderate doses of RAC, and to a lesser degree, SCH. In an acquisition study, six groups of rats received VEH, SCH (25, 50, 200 nmol/kg) or RAC (50, 200 nmol/kg) 0.5 h prior to 1-bottle training trials with CS+ flavored 3.5% and CS- flavored 0.9% (CS-) CO solutions. A seventh Limited VEH group was trained with its training intakes limited to that of the SCH and RAC groups. Subsequent two-bottle tests were conducted with the CS+ and CS- flavors presented in 0.9% CO without injections. Significant and persistent CS+ preferences were observed in VEH (75-82%), Limited VEH (70-88%), SCH25 (75-84%), SCH50 (64-87%), SCH200 (78-91%) and RAC200 (74-91%) groups. In contrast, the group trained with RAC50 displayed a significant initial CS+ preference (76%) which declined over testing to 61%. These data indicate limited DA D1 and D2 receptor signaling involvement in the expression and acquisition of a fat-CFP relative to previous robust effects for sugar-CFP.

Restoration of facial form and function after severe disfigurement from burn injury by a composite facial allograft

Composite facial allotransplantation is emerging as a treatment option for severe facial disfigurements. The technical feasibility of facial transplantation has been demonstrated, and the initial clinical outcomes have been encouraging. We report an excellent functional and anatomical restoration 1 year after face transplantation. A 59-year-old male with severe disfigurement from electrical burn injury was treated with a facial allograft composed of bone and soft tissues to restore midfacial form and function. An initial potent antirejection treatment was tapered to minimal dose of immunosuppression. There were no surgical complications. The patient demonstrated facial redness during the initial postoperative months. One acute rejection episode was reversed with a brief methylprednisolone bolus treatment. Pathological analysis and the donor's medical history suggested that rosacea transferred from the donor caused the erythema, successfully treated with topical metronidazol. Significant restoration of nasal breathing, speech, feeding, sensation and animation was achieved. The patient was highly satisfied with the esthetic result, and regained much of his capacity for normal social life. Composite facial allotransplantation, along with minimal and well-tolerated immunosuppression, was successfully utilized to restore facial form and function in a patient with severe disfigurement of the midface.

Role of pharmacogenetic studies in early clinical development: Phase I studies with lapatinib

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Background: Rash and diarrhea are a class effect of ERBB1 inhibitors. These events are relatively mild with Lapatinib (a dual ERBB1/ERBB2 kinase inhibitor). Finding a genetic basis for patients who may be predisposed to these adverse events, from the outset of clinical development, may improve the understanding of the mechanisms of these side effects and may have implications for use and dosing. Methods: DNA was isolated from peripheral blood of 107 Caucasian subjects from eight monotherapy phase I studies including 73 healthy volunteers and 34 cancer patients, 100 of whom had associated pharmacokinetic data. 284 single nucleotide polymorphisms (SNPs) from five candidate genes of transporters (ABCB1, ABCG2) and enzymes (CYP 3A4 and 3A5, and 2C19) for which lapatinib is a substrate were genotyped and examined for associations with pharmacokinetic variables (dose-normalized AUC, Cmax, and Tmax) as well as rash (15 cases) and diarrhea (18 cases). Results: Skin rash and diarrhea in this phase I cohort were only mild, (i.e. grade I or II). Statistically significant associations were observed between 34 SNPs in CYP2C19, rash (22 SNPs) and diarrhea (6 SNPs), and between 15 SNPs in ABCB1 and Tmax. Notably, 3/3 subjects (2 healthy volunteers, one patient) homozygous for the CYP2C19*2 allele experienced both mild rash and diarrhea. Extensive linkage disequilibrium was observed among these associated SNPs. Conclusions: Our results suggest that it is possible to determine pharmacogenetic associations with side effect phenotypes during the earliest phase of clinical drug development. These results are currently being validated on a larger cohort of patients from phase II lapatinib clinical trials.

[Table: see text]

Coronary artery bypass graft imaging using ECG-gated multislice computed tomography: Comparison with catheter angiography

AIM

To compare the value of multislice computerized tomography (MSCT) in imaging coronary artery bypass grafts (CABGs) by direct quantitative comparison with standard invasive angiography.

METHODS

Using MSCT, 50 consecutive patients who had previously undergone CABG surgery and had recently undergone invasive angiography for recurrent angina pectoris, were studied further using MSCT after intravenous injection of non-ionic contrast agent; cardiac imaging was performed during a single breath-hold. Graft anatomy was quantified, using both quantitative coronary angiography (QCA) and MSCT, by different investigators blinded to each other. Reproducibility was quantified using the standard error of the measurement expressed as a percentage in log-transformed values (CV%) and intraclass correlation (ICC).

RESULTS

All 150 grafts were imaged using MSCT; only 4 patent grafts were not imaged using selective angiography. Good agreement was achieved between MSCT and QCA on assessment of proximal anastomoses (CV% 25.2, ICC 0.84), mid-vessel luminal diameter (CV% 15.5, ICC 0.91) and aneurysmal dilations (CV% 14.3). Reasonable agreement was reached on assessment of distal anastomoses (CV% 26.7, ICC 0.66) and categorization of distal run-off (ICC 0.73). Good agreement was observed for stenoses of over 50% luminal loss (CV% 8.7, ICC 0.97) but agreement on assessment of less severe lesions was poor (CV% 208.7, ICC 0.51).

CONCLUSION

This study demonstrates that CABGs can be quantitatively evaluated using MSCT, and that significant lesions present in all CABG segments can be reliably identified. Agreement between MSCT and QCA for lesions of less than 50% luminal loss was poor.

Maternal diabetes mellitus is associated with altered deposition of fibrin-type fibrinoid at the villous surface in term placentae

Placentae from control and diabetic patients were used to test three null hypothesis: (1) there are no significant group differences in the volumes of villous syncytiotrophoblast compartments or intervillous fibrin-type fibrinoid, (2) perivillous fibrin-type fibrinoid is deposited randomly at the surface of trophoblast, and (3) amounts and deposition patterns of perivillous fibrin-type fibrinoid do not vary between groups. Term placentae were collected from non-diabetic subjects and five groups of diabetic women classified according to duration, severity and insulin dependence. Tissue specimens and sections were obtained by uniform random sampling. Volumes and surface areas of fibrin-type fibrinoid and trophoblast compartments (thin, syncytial knot, syncytial bridge and denuded regions) were estimated stereologically and compared using variance, chi-squared and contingency table analyses. As to null hypothesis (1), no group differences in volumes of trophoblast compartments were found but volumes of intervillous fibrin-type fibrinoid were greater in the non-insulin-dependent diabetic group. As to null hypothesis (2), regardless of group, fibrin-type fibrinoid was deposited preferentially at sites of denudation in every placenta examined. As to null hypothesis (3), villous surface areas occupied by perivillous fibrin-type fibrinoid were greater in type 1 (insulin-dependent) diabetics with complications (diabetic nephropathy or retinopathy). The surfaces of trophoblast occupied by fibrin-type fibrinoid were also notably larger in non-insulin-dependent diabetics and type 1 diabetics with complications. Except for the surface of denudation sites (which also increased in diabetes), there were no differences in the surfaces of trophoblast regions. These results confirm that the haemostatic steady state is perturbed in the diabetic placenta, that perivillous fibrin-type fibrinoid is deposited preferentially at sites of epithelial loss/damage, and that some diabetic groups are affected differentially.

A review of computer-aided body surface area determination: SAGE II and EPRI's 3D Burn Vision

Estimates of percent body surface area (%BSA) burns correlate well with fluid needs, nutritional requirements, and prognosis. Most burn centers rely on the Lund Browder chart and "rule of nines," to calculate the %BSA. Computer-based methods may improve precision and data analysis. We studied two new methods of determining %BSA: a two-dimensional Web-based program (Sage II) and a three-dimensional computer-aided design program (EPRI 3D Burn Vision). Members of our burn team found the Sage II program easy to use and found many of the features useful for patient care. The EPRI program has the advantage of 3D images and different body morphologies but required training to use. Computer-aided methods offer the potential for improved precision and data analysis of %BSA measurements.

Transforming growth factor-beta has contrasting effects in the presence or absence of exogenous interleukin-12 on the in vitro activation of cells that transfer experimental autoimmune thyroiditis

Mouse thyroglobulin (MuTg)-sensitized spleen cells activated in vitro with MuTg induce experimental autoimmune thyroiditis (EAT) in recipient mice with a thyroid infiltrate consisting primarily of lymphocytes. A more severe and histologically distinct granulomatous form of EAT (G-EAT) is induced when donor cells are activated with MuTg together with anti-interferon-gamma (IFN-gamma), anti-interleukin-2 receptor (IL-2R) monoclonal antibody (mAb), and IL-12. Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that can both suppress and exacerbate autoimmune diseases and often has inhibitory effects on lymphocytes. To determine if TGF-beta could modulate the in vitro activation of effector cells for G-EAT, TGF-beta was added to cultures of MuTg-sensitized donor spleen cells together with MuTg. Cells activated in the presence of 2 ng/ml TGF-beta induced moderately severe G-EAT in recipient mice. G-EAT induced by cells activated in the presence of TGF-beta was histologically similar but less severe than the G-EAT induced by cells activated in the presence of IL-12. IL-12 and TGF-beta modulate the activation of G-EAT effector cells by distinct mechanisms, as cells activated by TGF-beta could induce G-EAT in the presence of anti-IL-12, and TGF-beta inhibited the effects of IL-12 on EAT effector cells. TGF-beta exerted its activity during the first 24 h of the 72-h culture, whereas IL-12 functioned primarily during the final 24 h of culture. These results indicate that thyroid lesions with granulomatous histopathology can be induced by both IL-12-dependent and IL-12-independent mechanisms, and TGF-beta can exert both positive and negative effects on the effector cells for G-EAT.

Cloning and characterization of cDNAs encoding four different canine immunoglobulin gamma chains

cDNAs encoding four different canine immunoglobulin G (caIgG) gamma chains were identified in this study. One of these IgG gamma chain cDNAs, (caIgG-A), represents 92.5% of the IgG gamma chain cDNAs in a dog spleen cell cDNA library; a second partial IgG gamma chain cDNA (caIgG-B) was also identified in the library. The other two IgG gamma chain cDNAs (caIgG-C and caIgG-D) were RT-PCR amplified from canine lymphoma samples. Comparison of the four different canine IgG gamma chain cDNAs showed homologies from 83.6 to 89.2% and from 73.1 to 81.8% at nucleotide and amino acid sequence levels, respectively. Despite the high similarity in CH1, CH2 and CH3 domains among the different caIgG gamma chains, the hinge regions were distinct, sharing only 19.0-35.2% homology at the amino acid level. No multiple duplication of the hinge region, as reported for human IgG1 and IgG3, was detected in any of the canine IgG gamma chains. The numbers of cysteines in the putative hinge regions were found to be 3, 2, 7 and 3 for the four canine IgG heavy gamma chains (A, B, C and D), respectively. Specific primers were designed based on caIgG gamma chain hinge region DNA sequences and were used in RT-PCR for measuring different caIgG gamma chain mRNA levels in canine PBMC samples.

Intramural hematoma of the aorta caused by a penetrating atheromatous ulcer

Aortic dissection is a life-threatening condition which is difficult to diagnose because of its variable clinical presentation and diverse pathophysiologic manifestations. We present a case in which intramural hematoma of the thoracic aorta occurred in the absence of an intimal flap. Computed tomography and magnetic resonance imaging both showed hemorrhage in the wall of the aorta. Transesophageal echocardiography also revealed a penetrating atherosclerotic ulcer in the transverse aorta as a cause of the hematoma. A high index of clinical suspicion and a combination of diagnostic procedures resulted in proper diagnosis and successful surgical treatment.

Magnetic resonance acquisition to determine the lumen length of a tortuous phantom aorta

PURPOSE

Endovascular abdominal aortic aneurysm repair is a technique that requires an accurate measurement of the aneurysm's lumen length prior to the procedure. This study examines the accuracy of luminal length measurement in an aortic phantom using magnetic resonance angiography (MRA) axial source images.

METHODS AND RESULTS

Tortuous phantom aortas were constructed using water-filled plastic tubing (7 mm in diameter with lengths of 80 to 160 mm). The tubes were molded into three-dimensional "S" or "C" shapes that simulated the luminal course of a tortuous aorta. Phantoms were imaged at angles of 0 degrees, 15 degrees, 30 degrees, and 45 degrees to the image slice direction on a 1.5T Signa MR scanner using a transaxial two-dimensional time-of-flight (TOF) and a T1-weighted spin-echo acquisition. The luminal length of the phantom was calculated after establishing the lumen center coordinates in axial source images and then measuring the distance between two sequential slices using the Pythagorean theorem. The accuracy of this measurement in the phantom was 89% to 99.6%, proportional to the length of the tubing. Accuracy was not affected by angulation of < 45 degrees.

CONCLUSION

Two-dimensional TOF MRA source images can provide an accurate measurement of the phantom aorta's lumen length.

Saphenous vein graft pseudoaneurysm: diagnosis by transesophageal echocardiography and magnetic resonance imaging

Coronary cineangiography showed probable pseudoaneurysm formation at the origin of an 11-year-old saphenous vein coronary bypass graft. Transesophageal echocardiography and magnetic resonance imaging were helpful in differentiating this from aortic dissection or true aneurysm formation and assisted the surgeon in avoiding perforation of the pseudoaneurysm during sternotomy.

"Pseudocoarctation" of the aorta

Images

Venoatrial pathways after the Mustard operation for transposition of the great arteries: anatomic and functional MR imaging

PURPOSE

To evaluate spin-echo (SE) and cine gradient-echo (GRE) magnetic resonance (MR) imaging with velocity mapping for detecting late complications of the Mustard operation.

MATERIALS AND METHODS

Twenty-one patients were studied with MR imaging 1-22 years after undergoing the Mustard operation. Twenty were also studied with transthoracic echocardiography, 18 with angiocardiography, and five with transesophageal echocardiography.

RESULTS

MR imaging showed no venoatrial obstruction in nine patients. This result was confirmed with angiocardiography in seven cases and postmortem examination in one case. In one case, MR imaging demonstrated a leak at the baffle suture line. Of 12 cases with venoatrial obstruction at MR imaging, nine were confirmed with angiocardiography or surgery. There were two false-positive MR studies and one case in which no conclusion was reached.

CONCLUSION

With addition of cine GRE sequences and velocity mapping to SE sequences, MR imaging is a useful noninvasive method of investigating late complications of the Mustard operation.

Acquired arteriovenous fistulas in children

Five boys with acquired arteriovenous fistulas are presented; four had factor VIII deficiencies, and one had a hepatic-induced coagulopathy. The cause of the fistula was the trauma induced by single or repeated venous and/or arterial punctures. All five developed a slowly progressive pulsatile mass of over a period of months. Patients with coagulopathies all developed complications with repeated inadvertent puncture of these masses. Clinical examination and magnetic resonance imaging scans clearly highlight this problem. Surgical ligation is recommended for progressive enlargement.