Self-reported adverse reactions to subcutaneous airborne allergen immunotherapy: a real-life, single center study

Summary

Objective. To estimate the prevalence of self-reported adverse reactions (AdR) to subcutaneous airborne allergen immunotherapy (SCIT) and to describe factors associated with its occurrence. Methods. Real-life, observational, descriptive study of all patients treated with SCIT at a Portuguese allergy unit between 03/2017 and 06/2019, and who answered ≥1 time to a pre-SCIT evaluation questionnaire assessing the occurrence of local and/or systemic AdR in the previous administration. Results. 939 questionnaires from 231 patients (42% female, 35% with asthma) were included. Most (60%) SCIT preparations had multiple allergens with concentration adjusted to prevent dilution (MA-NoDil), 26% were single allergen with standard concentration (SA-SC), 10% single allergen with higher than standard concentration (SA-HC), and 4% mixtures without concentration adjustment (MA-Dil). SCIT-related AdR were self-reported in 313 (33%) administrations, 97% at the injection site and 11% grade 1 systemic symptoms. In a multivariable model, being a female and having asthma were associated with higher risk of AdR. MA-NoDil SCIT presented a lower risk of AdR compared to SA-SC SCIT. Conclusions. SCIT-related AdR were self-reported in 1/3 of the administrations, most at the injection site. The risk of AdR was higher in females and in patients with asthma. The lower risk of adverse reactions observed in SCIT preparations with multiple allergens with no dilutional effect should be further explored in future, targeted studies.

The relationship between perfectionism, generalized problematic internet use and bulimic behaviours

Introduction

Perfectionism is a consistent risk factor for various psychopathological conditions, including psychological distress and eating disorders. Recently, we have shown, for the first time, that there is a relationship between perfectionism and generalized problematic internet use/GPIU (Sobral et al. 2020). Specifically, we found that the role of perfectionism in psychological disorder is partially mediated by GPIU. On the other hand, it has been suggested that the widespread use of digital media can lead to negative body image perception and abnormal eating attitudes and behaviors.

Objectives

To explore, for the first time, the relationship between perfectionism, GPIU and disordered eating behavior.

Methods

475 university students (78.9% girls; mean age 20.22±1.695) answered the Portuguese validated versions of: Composite Multidimensional Perfectionism Scale, GPIU Scale and Eating Attitudes Test-25. SPSS and Hayes’ Process Macro (2020) were used.

Results

Bulimic Behaviours/BB significantly and moderately correlated with Perfectionist efforts (r=.263), Perfectionist concerns (r=.284) and GPIU (r=.25) (all p<.001). The mediation analyses revealed that GPIU is a partial mediator of the relationship between both perfectionism dimensions and BB.

Conclusions

The evidence that both negative and “positive” perfectionism dimensions are associated to eating pathology is in line with our previous research. The present study adds, for the first time, that one of the perfectionism pathways of influence on BB operates through UGPI. Assessment and intervention to diminish eating psychopathology should focus on perfectionism and compulsive traits which could be involved in both ED and GPIU and in their comorbidity.

Disclosure

No significant relationships.

Ecophysiological Performance of Proteaceae Species From Southern South America Growing on Substrates Derived From Young Volcanic Materials

Southern South American Proteaceae thrive on young volcanic substrates, which are extremely low in plant-available phosphorus (P). Most Proteaceae exhibit a nutrient-acquisition strategy based on the release of carboxylates from specialized roots, named cluster roots (CR). Some Proteaceae colonize young volcanic substrates which has been related to CR functioning. However, physiological functioning of other Proteaceae on recent volcanic substrates is unknown. We conducted an experiment with seedlings of five Proteaceae (Gevuina avellana, Embothrium coccineum, Lomatia hirsuta, L. ferruginea, and L. dentata) grown in three volcanic materials. Two of them are substrates with very low nutrient concentrations, collected from the most recent deposits of the volcanoes Choshuenco and Calbuco (Chile). The other volcanic material corresponds to a developed soil that exhibits a high nutrient availability. We assessed morphological responses (i.e., height, biomass, and CR formation), seed and leaf macronutrient and micronutrient concentrations and carboxylates exuded by roots. The results show that G. avellana was less affected by nutrient availability of the volcanic substrate, probably because it had a greater nutrient content in its seeds and produced large CR exuding carboxylates that supported their initial growth. Embothrium coccineum exhibited greater total plant height and leaf P concentration than Lomatia species. In general, in all species leaf macronutrient concentrations were reduced on nutrient-poor volcanic substrates, while leaf micronutrient concentrations were highly variable depending on species and volcanic material. We conclude that Proteaceae from temperate rainforests differ in their capacity to grow and acquire nutrients from young and nutrient-poor volcanic substrates. The greater seed nutrient content, low nutrient requirements (only for G. avellana) and ability to mobilize nutrients help explain why G. avellana and E. coccineum are better colonizers of recent volcanic substrates than Lomatia species.

Rabdomiólise em militares: uma missão de reconhecimento para prevenção

O treinamento físico regular faz parte do cotidiano militar, com intuito de aprimorar competências físicas essenciais para tarefas de combate. No entanto, quando executado de forma extenuante ou desenvolvido em condições climáticas adversas pode ocasionar o desenvolvimento da rabdomiólise por esforço físico. A rabdomiólise por esforço físico é definida como uma síndrome decorrente da necrose das células musculares, com sintomas variáveis, como dor muscular, fraqueza e aumento plasmático de enzimas musculares. A severidade da rabdomiólise por esforço físico varia individualmente, porém, pode se tornar clinicamente relevante, contribuindo para a hospitalização, insuficiência renal aguda, incapacidade permanente ou óbito. Sendo assim, o objetivo desta revisão narrativa é apresentar possíveis causas e fatores de risco para rabdomiólise, discutir sua fisiopatologia, seus possíveis diagnósticos e suas principais complicações, enfatizando o contexto militar.

EXTH-17. LOCAL DELIVERY OF CYTOKINES AND SYNTHETIC IMMUNOMODULATORS INCREASES T CELL INFILTRATION AND SIGNIFICANTLY IMPROVES SURVIVAL IN A POORLY IMMUNOGENIC MODEL OF GLIOBLASTOMA

BACKGROUND

Severe local and systemic immune suppression in glioblastoma (GBM) contributes to the failure of single-agent immunotherapies in clinical trials. In this study, we evaluated the efficacy of locally delivered combination immunotherapy in a poorly immunogenic murine GBM model.

METHODS

Immunomodulators used in these studies included: IL-15 and IL-7 (T cell activation), LIGHT (T cell tumor infiltration), FLT3L (dendritic cell maturation/proliferation), a surface T cell engager (T cell killing of tumor cells), and a bispecific PD-L1/T cell engager (T cell killing targeted to PD-L1-expressing cells). We first assessed T cell-mediated cytotoxicity in vitro against SB28, a poorly immunogenic murine GBM cell line, after expressing these immunomodulators in combination. Next, tumor growth inhibition in vivo was evaluated in syngeneic C57BL/6 mice, initially by establishment of intracranial tumors with pre-transduced SB28 cells, and subsequently by delivering these immunomodulators to pre-established naïve SB28 tumors using neural stem cells (NSCs) and retroviral replicating vectors (RRV).

RESULTS

SB28 cells transduced with immunomodulators activated dose-dependent T cell-mediated cytotoxicity in vitro. Mice with pre-transduced intracranial SB28 gliomas showed significantly longer survival (minimum survival: 60 days, long-term survival in 57% of mice) vs. control mice (median survival: 20 days) (p&lt; 0.001), and significantly increased tumor infiltration of CD4+ and CD8+ T cells. NSC- and RRV-mediated immunomodulator delivery to pre-established SB28 gliomas also resulted in significantly increased survival of treated mice vs. controls (median survival: 31 days vs. 22 days, p&lt; 0.001). Immunomodulator-treated tumors again showed significantly increased infiltration of CD4+ and CD8+ T cells, along with decreased CD11b+ cell infiltration.

CONCLUSIONS

A novel combination therapy for GBM immunotherapy activated T cell killing of SB28 GBM cells in vitro and achieved a significant survival benefit in vivo, associated with anti-tumor alterations to the GBM tumor microenvironment. Further studies to optimize the efficiency of combinatorial immunomodulator delivery are currently underway.

NCOG-51. CORRELATION BETWEEN TUMOR VOLUME AND SERUM PROLACTIN AND IMPACT OF TUMOR CELLULAR DENSITY ON PROLACTINOMA SURGICAL OUTCOMES IN A COHORT OF 181 PATIENTS

INTRODUCTION

Prolactinomas are common pituitary adenomas managed medically or surgically.

METHODS

Reviewed 181 prolactinomas resected transsphenoidally 2012-2019. Tumor volumes were quantified using BrainLab Smartbrush. Pearson correlation analysis and linear regression were used to identify associations between tumor volumes and serum prolactin. Tumor density was defined as serum prolactin divided by tumor volume.

RESULTS

Mean tumor volume was 6.33cm3 and mean pre-op prolactin was 803.4ug/L, with men having larger (12.11 vs 2.93cm3;p&lt; 0.001) and women having denser (173.9 vs 107.6ug/L/cm3;p=0.011) prolactinomas. Pearson correlation (R=0.688;p&lt; 0.001) and linear regression revealed a strong association between pre-op volume and prolactin levels, with 96.9g/L increase in prolactin/cm3 increase in volume (p&lt; 0.001); this holds true for men (R=0.584;p&lt; 0.001) and women (R=0.939;p&lt; 0.001), with women demonstrating greater prolactin/cm3 tumor density (186.5 vs 75.0ug/L;p&lt; 0.001). MiB index did not correlate with pre-op volume (p=0.449) or pre-op prolactin (p=0.452). Logistic regression showed decreased biochemical remission with increasing pre-op volume (OR=0.891;p&lt; 0.001). Increased MiB index (p=0.971) and p53 (p=0.525) staining did not affect remission rates. Positive PIT-1 staining was associated with higher remission rates (OR=2.508;p=0.005). Patients without remission had denser tumors (149.9 vs. 100.6ug/L/cm3;p=0.013), with Pearson correlation yielding R=0.736 between pre-op volume and pre-op prolactin (p&lt; 0.001), and R=0.476 between residual volume and post-op prolactin (p&lt; 0.001). Patients without remission exhibited 142.9ug/L increase in prolactin/cm3 of pre-op volume (p&lt; 0.001), higher than the 58.9ug/L increase in prolactin/cm3 in patients with remission (p&lt; 0.001). Patients without remission had residual tumors with 68.4ug/L increase in prolactin/cm3 of remaining volume after resection (p&lt; 0.001).

CONCLUSION

Our analysis revealed significant correlation between prolactinoma volume and serum prolactin levels. Patients without remission had greater tumor cellular density than those with remission. The volume-prolactin correlation persisted post-operatively, although surgery reduced tumor density. These results could identify prolactinomas for which surgery could achieve biochemical remission.

NCOG-54. SAFETY OF TRANSSPHENOIDAL SURGERY FOR NONFUNCTIONING PITUITARY ADENOMA IN ELDERLY PATIENTS

INTRODUCTION

Life expectancy has increased over the past century, shifting the demographic distribution towards older age groups. Elderly patients comprise up to 14% of patients with pituitary tumors, with most lesions being nonfunctioning adenomas (NFPAs). Here, we compare clinical and surgical outcomes and post-operative complications between non-elderly adult (age ≥ 18 years and ≤ 65 years) and elderly (age &gt; 65 years) NFPA patients.

METHODS

Retrospective review of 908 patients undergoing transsphenoidal surgery for NFPA at a single institution from 2007-2019.

RESULTS

Elderly patients represented 32.4% of patients. Both groups were similar in gender (57.3% vs 60.5% male;P=0.4), tumor size (2.56 vs 2.46 cm;P=0.2), and cavernous sinus invasion (35.8% vs 33.7%;P=0.6). Regarding post-operative outcomes, length of stay (1 vs 2 days; P=0.5), extent of resection (59.8% vs 64.8% GTR;P=0.2), CSF leak requiring surgical revision (4.3% vs 1.4%;P=0.06), 30-day readmission (8.1% vs 7.3%;P=0.7), infection (3.1% vs 2.0%;P=0.5), and new hypopituitarism (13.9% vs 12.0%;P=0.3) were similar between both groups. Elderly patients were less likely to have adjuvant radiation (8.7% vs 16.3%;P=0.009), future re-operation (3.8% vs 9.5%;P=0.003), and post-operative diabetes insipidus (DI) (3.7% vs 9.4%;P=0.002), and more likely to have post-operative hyponatremia (26.7% vs 16.4%;P&lt; 0.001) and new cranial nerve deficit (1.9% vs 0.0%;P=0.01). Elderly patients’ post-operative sodium peaked and troughed on POD3 (mean=138.7 mEq/L) and POD9 (mean=130.8 mEq/L), respectively, compared to non-elderly patients (peak POD2 mean=139.9 mEq/L, trough POD8 mean=131.3 mEq/L).

CONCLUSION

Our analysis revealed that elderly patients experienced more post-operative hyponatremia, while non-elderly patients experienced more post-operative DI. Elderly patients also experience later peak and trough in serum sodium, suggesting age-related differences in stalk-related morbidities of NFPA resection. Overall, our results show that transsphenoidal surgery for NFPA in elderly patients is safe with low complication rates. We hope our results will guide discussions with elderly patients regarding possible risks and outcomes.

SURG-25. EFFECT OF VENTRICULAR ENTRY DURING GLIOBLASTOMA RESECTION ON PATIENT OUTCOMES

BACKGROUND

Tumor proximity to the ventricle and ventricular entry (VE) during surgery have both been associated with poorer prognoses; however, the interaction between these two factors is poorly understood.

METHODS

The UCSF tumor registry was searched for patients with newly diagnosed and recurrent supratentorial glioblastoma who underwent surgical resection with the senior author between 2013 – 2018. Tumor location with respect to the subventricular zone (SVZ), size, VE, and extent of resection were assessed using pre and postoperative imaging.

RESULTS

In the 200-patient cohort of newly diagnosed and recurrent glioblastoma, 26.5% had VE. Comparing patients with VE to those without VE, there was no difference in postoperative hydrocephalus (1.9% vs. 4.8%, p = 0.36), ventriculoperitoneal shunting (0% vs. 3.4%, p = 0.17), pseudomeningoceles (7.5% vs. 5.4%, p = 0.58), or subdural hematomas (11.3% vs. 3.4%, p = 0.07). Importantly, rates of leptomeningeal disease (7.5% in VE vs. 10.2% w/o VE, p = 0.57) and distant parenchymal recurrence (17.9% in VE vs. 23.1% w/o VE, p = 0.35) were not different between the groups. There was no effect of VE on EOR when controlling for SVZ type. Newly diagnosed patients with tumors contacting the SVZ (Type 1 or 2) had worse survival than patients with tumors that did not contact the SVZ (Type 3 or 4) (1.27 vs 1.84 years, p = 0.014, HR 1.8, CI 1.08 – 3.03), but VE was not associated with worse survival in these patients with high risk SVZ Type 1 and 2 tumors (1.15 vs 1.68 years, p = 0.151, HR 0.59, CI 0.26 – 1.34).

DISCUSSION

VE was well tolerated with complications being rare events. There was no increase in leptomeningeal spread or distant parenchymal recurrence in patients with VE. Finally, VE did not change survival for patients with tumors contacting the ventricle.

Stopping targeted therapy for complete responders in advanced BRAF mutant melanoma

BRAF inhibitors revolutionised the management of melanoma patients and although resistance occurs, there is a subgroup of patients who maintain durable disease control. For those cases with durable complete response (CR) it is not clear whether it is safe to cease therapy. Here we identified 13 patients treated with BRAF +/- MEK inhibitors, who cease therapy after prolonged CR (median = 34 months, range 20-74). Recurrence was observed in 3/13 (23%) patients. In the remaining 10 patients with sustained CR off therapy, the median follow up after discontinuation was 19 months (range 8-36). We retrospectively measured ctDNA levels using droplet digital PCR (ddPCR) in longitudinal plasma samples. CtDNA levels were undetectable in 11/13 cases after cessation and remained undetectable in patients in CR (10/13). CtDNA eventually became detectable in 2/3 cases with disease recurrence, but remained undetectable in 1 patient with brain only progression. Our study suggests that consideration could be given to ceasing targeted therapy in the context of prolonged treatment, durable response and no evidence of residual disease as measured by ctDNA.

The Situation Room as a management tool: the case of the Municipal Health Secretariat of Salvador

Problem

The Salvador Municipal Health Secretariat (MHS) utilizes health data to elaborate technical documents to manage and respond to instances requiring internal or external control. In answer to demands for the modernization and transparency of municipal management, the constitution of a Health Situation Room (HSR) was included in the political agenda of the Secretary, thereby guaranteeing political, technical and operational support for its implementation.

Description of the Problem

To describe the process of construction of the HSR in the Salvador MHS in 2020. The HSR is a physical, virtual and collective space for the analysis of information, which begins with a data search which allows to understand the information flow, identifying the solicitor and the constructor of the information, the data source and the informational object itself.

Results

130 technicians and managers were interviewed, and their responses then categorized into 161 indicators across different themes. The results point out the need to define a spatial analysis unit to be adopted, and to communicate with external actors who demand information, as well as to develop a communication plan for the HSR.

Lessons

To develop an informational culture oriented by local and central protagonism, generating evidence for decision-making and information transparency for the whole of society.

Key messages

The Health Situation Room reduces the time between information-decision-action. The Health Situation Room prioritizes interdisciplinary collaboration and increases the efficiency of the health system.

Hospitalization direct cost of adults with community-acquired pneumonia in Portugal from 2000 to 2009

INTRODUCTION

Hospitalizations due to community-acquired pneumonia (CAP) in mainland Portugal from 2000 to 2009 accounted for 3.7% of all hospital admissions in population with 18 or more years of age. There is no direct-cost data regarding these admissions.

METHODS

In this observational descriptive study all adult hospitalizations associated with CAP diagnosis were retrospectively analyzed for the period between 2000 and 2009. Patients under 18 years old, those with pneumonia as secondary diagnosis, patients with tuberculous or obstructive pneumonia, and immunocompromised patients were excluded from the study. The direct cost of hospitalization was calculated according to the diagnosis-related groups (DRG), established for the respective year of hospitalization.

RESULTS

There were 294,026 hospital admissions with an average annual direct cost of 80 million Euros, which almost doubled between 2000 and 2009. The average direct hospitalization costs per admission, including wards and Intensive Care Units (ICU), amounted to €2,707, with an increasing trend. The average hospitalization cost was €2,515 for admissions resulting in live discharge, and €3,457 for the deceased.

CONCLUSION

The average direct cost of adult hospitalizations associated with CAP amounted to €2,707 in mainland Portugal from 2000 to 2009, showing an increase of 37.5% in hospitalization cost of living and deceased patients. The economic impact of CAP-related hospital admissions justifies the need for better implementation of preventive measures.

P1377Substrate-based ablation in patients with frequent appropriate ICD therapy and dilated cardiomyopathy: long-term experience with high-density mapping

Recurrent ventricular tachydisrhythmias (VT) episodes have a negative impact in the outcome of patients (P) already with an implantable cardioverter-defibrillator (ICD). Elimination of arrhythmic reentry circuits represents a difficult challenge, mainly due to the induction of intolerable VTs, with multiple ECG morphologies, requiring rapid interruption. Substrate guided ablation has been used as a promising approach strategy to treat recurrent VTs. Aim: to assess long-term results of a VT substrate-based ablation using high-density mapping in P with an ICD, severe left ventricular (LV)  dysfunction and recurrent appropriate ICD therapy. Methods: 16P (12 men, non-ischemic cardiomyopathy 67%, 55 ± 13 years, LV ejection fraction 32 ± 6%) and recurrent appropriate shocks despite antiarrhythmic drug therapy and optimal heart failure medication. All P underwent a protocol of ventricular programmed stimulation (600 ms/S3) to obtain baseline VT documentation. A sinus rhythm (SR) voltage map was created using a 3D electroanatomic mapping system (CARTO) with a high-density mapping catheter (PentaRay) to delineate areas of scarred myocardium (ventricular bipolar voltage ≤0,5 mV – dense scar; 0,5-1,5 mV – border zone; ≥1,5 mV – healthy tissue) and provide high-resolution electrophysiological mapping. The substrate modification included catheter elimination of local abnormal ventricular activities (LAVA) - fractionated, splited, low-amplitude/long-lasting, late potentials, pre-systolic potentials - and linear ablation to obtain scars homogenization and scar dechanneling. Pace-mapping techniques were used when capture was possible. LV approach was retrograde in 6 cases, transeptal in 4 and endo-epicardial in 2 cases. In 2P the ablation was performed in the right ventricle. Results: VTs were induced and interrupted with bursts or external DC shocks. LAVA were identified and ablated in all P. Eleven P underwent modification of scar areas. The mean duration of the procedure was 153 mn (103-218 mn), with radiofrequency ranging from 18 to 60 mn (mean 33 min), and a mean fluoroscopy time of 16 mn. Non-inducibility was achieved in 75% of the cases. There was 1 pericardial tamponade drained successfully. During a follow-up of 48 ± 18 months, 75% had no VT recurrences, 2P underwent redo ablation, 1P died from stroke. Conclusion: Catheter ablation of VT based on substrate modification guided by high-density mapping is feasible and safe in P with LV dysfunction. This approach may be of clinical relevance, with potential benefits in reducing VT burden.

Primary papillary epithelial tumour of the sella: expanding the spectrum of TTF-1-positive sellar lesions

AIM

To describe four novel primary epithelial tumours of the sella with papillary architecture and Thyroid Transcription Factor 1 (TTF-1) expression.

METHODS

Paraffin-embedded tissue from the four cases and recurrence of patient 1 was investigated with haematoxylin-eosin, special histochemical stains, immunohistochemistry with a broad panel of antibodies and next-generation sequencing. The ultrastructure of one tumour was studied in tissue retrieved from paraffin.

RESULTS

The lesions occurred in three females aged 20, 26 and 42 years and a male aged 49 years. They presented with signs and symptoms secondary to pituitary stalk compression. Preoperative neuroimaging documented mixed solid and cystic, enhancing sellar masses with suprasellar extension. Histologically, the tumours showed thin papillae lined by a single layer of cytokeratin and TTF-1-positive cuboidal and cylindrical cells with mildly atypical nucleus. Next-generation sequencing performed in three cases did not identify any mutations. The main differential diagnosis included metastasis from lung or thyroid carcinoma, extraventricular choroid plexus papilloma and sellar ependymoma.

CONCLUSION

We suggest the descriptive term of primary papillary epithelial tumour of the sella (PPETS) for this entity and propose that it could represent the intracranial equivalent of thyroid-like low-grade nasopharyngeal papillary adenocarcinoma. The cell of origin of PPETS remains undetermined although the intense and ubiquitous expression of TTF-1 may suggest a derivation from the infundibulum or ventricular recess. Our study expands the spectrum of sellar TTF-1-positive tumour and challenges the view that they all derive from pituicytes.

Host engulfment pathway controls inflammation in inflammatory bowel disease

Chronic diseases, including inflammatory bowel disease (IBD) urgently need new biomarkers as a significant proportion of patients, do not respond to current medications. Inflammation is a common factor in these diseases, and microbial sensing in the intestinal tract is critical to initiate the inflammation. We have identified ELMO1 (engulfment and cell motility protein 1) as a microbial sensor in epithelial and phagocytic cells that turns on inflammatory signals. Using a stem cell-based 'gut-in-a-dish' coculture model, we studied the interactions between microbes, epithelium, and monocytes in the context of IBD. To mimic the in vivo cell physiology, enteroid-derived monolayers (EDMs) were generated from the organoids isolated from WT and ELMO1-/- mice and colonic biopsies of IBD patients. The EDMs were infected with the IBD-associated microbes to monitor the inflammatory responses. ELMO1-depleted EDMs displayed a significant reduction in bacterial internalization, a decrease in pro-inflammatory cytokine productions and monocyte recruitment. The expression of ELMO1 is elevated in the colonic epithelium and in the inflammatory infiltrates within the lamina propria of IBD patients where the higher expression is positively correlated with the elevated expression of pro-inflammatory cytokines, MCP-1 and TNF-α. MCP-1 is released from the epithelium and recruits monocytes to the site of inflammation. Once recruited, monocytes require ELMO1 to engulf the bacteria and propagate a robust TNF-α storm. These findings highlight that the dysregulated epithelial ELMO1 → MCP-1 axis can serve as an early biomarker in the diagnostics of IBD and other inflammatory disorders.

Influence of thickness and translucency of lithium disilicate ceramic on degree of conversion of resinous materials

Background

In this study was assessed the degree of conversion (DC) of amine-free resin cements light cured through lithium disilicate-reinforced ceramics at different thicknesses and translucency.

Material and Methods

Specimens were divided into 21 groups (n = 5) according to luting agent used: Variolink Esthetic LC (Light shade), RelyX Ultimate (A1 shade), and Filtek Z350 XT Flow (A1 shade); the ceramic translucency: low (LT) and high (HT); and the ceramic thickness: no ceramic (control), 0.5 mm, 1 mm, and 2 mm. A Teflon mold with (5 x 5 x 0.5 mm) was used to standardize the cement and over it the ceramic block from each group was placed. Set was cured using a polywave LED light (1200 mW/cm2 - Bluephase G2) for 40 s. FTIR spectra of uncured and cured materials was obtained and DC calculated from the height of the peaks 1610 and 1640 cm-1. Data were submitted to ANOVA followed by Tukey’s test (α = 0.05).

Results

There was a significant difference for luting agents (p< 0.0001) and translucency (p = 0.025), but not for thickness (p = 0.73). Dual amine-free RelyX Ultimate showed the lowest DC values and higher translucency promoted higher DC.

Conclusions

Dual amine-free cement showed the lowest monomer conversion and higher translucency ceramics promoted a higher DC.

Key words:Ceramic, degree of conversion, resin cement, thickness, translucency.

Determination of Low-Level Glucose and Fructose in Raw and Refined Crystalline Sugar by High-Performance Anion-Exchange Chromatography: Collaborative Study

A method was developed and a collaborative study was performed under the auspices of the International Commission of Uniform Methods for Sugar Analysis. The collaborators used high-performance anion-exchange chromatography (HPAEC) to determine trace amounts of glucose and fructose in 3 raw and 3 refined sugar samples provided as blind duplicates. Fourteen laboratories participated in the study. Although difficulties were experienced by a few analysts, 10 laboratories reported positive results. Average repeatabilities and reproducibilities for glucose and fructose in raw sugar were slightly above 5 and 10%, respectively, and the average Horwitz ratios were well under 2. Average repeatabilities and reproducibilities for glucose and fructose in refined sugar were 10 and 22%, respectively; although the Horwitz ratios were &gt;2, they were marginal (2.8). The HPAEC results agreed with results obtained by gas chromatography in an independent laboratory. Because the method was collaboratively studied according to the protocol of the International Union of Pure and Applied Chemistry for collaborative studies, and the results meet its criteria, it is recommended that the method be adopted Official First Action by AOAC INTERNATIONAL.