The degree of bowel remission predicts phenotype progression in Crohn's disease

BACKGROUND

Patients with Crohn's disease (CD) are at risk of progressing from inflammatory to stricturing and penetrating phenotypes. The influence of the depth of remission on the risk of progression has not been adequately evaluated.

METHODS

A retrospective cohort study including surgically naïve CD patients with inflammatory phenotype evaluated concomitantly by magnetic resonance enterography and colonoscopy. The degree of remission was correlated with the risk of progressing to stricturing and penetrating phenotypes.

RESULTS

Three hundred nineteen CD patients were included: 27.0% with transmural remission, 16.0% with isolated endoscopic remission, 14.4% with isolated radiologic remission, and 42.6% without remission. Patients with transmural remission presented the lowest rates of phenotype progression (1.2%), with a significant difference compared to isolated radiologic remission (10.9%, p = 0.019), to isolated endoscopic remission (19.6%, p ≤ 0.001), and to no remission (46.3%, p ≤ 0.001). In multivariate regression analysis, transmural remission (OR 0.017 95% CI 0.002-0.135, p < 0.001), isolated radiologic remission (OR 0.139 95% CI 0.049-0.396, p < 0.001), and isolated endoscopic remission (OR 0.301 95% CI 0.123-0.736, p = 0.008) resulted in lower rates of phenotype progression compared to no remission. No patient with transmural or isolated radiologic remission progressed to penetrating phenotypes.

CONCLUSION

The degree of bowel remission correlates with the risk of phenotype progression. Patients with transmural remission are at the lowest risk of progressing to stricturing and penetrating phenotypes.

Tight control using fecal calprotectin and early disease intervention increase the rates of transmural remission in Crohn's disease

BACKGROUND

Increasing evidence supports the use of transmural remission as a treatment target in Crohn's disease (CD), but it is seldom achieved in clinical practice. Tight monitoring of inflammation using fecal calprotectin with reactive treatment escalation may potentially improve these results.

AIMS

To evaluate if treatment escalation based on fecal calprotectin can improve the rates of transmural remission in CD. The influence of the timing of intervention on this strategy was also evaluated.

METHODS

Retrospective cohort study including 256 CD patients with 2 consecutive assessments by MRI-enterography and colonoscopy and with regular monitoring using fecal calprotectin. For each occurrence of an elevated fecal calprotectin (≥250 μg/g), we evaluated whether a reactive adjustment of medical treatment was performed. The ratio of treatment escalation/elevated fecal calprotectin was correlated with the chances of reaching transmural remission. Early disease was defined as disease duration <18 months without previous exposure to immunomodulators and biologics.

RESULTS

After a median follow-up of 2 years (IQR 1-4), 61 patients (23.8%) reached transmural remission. Ratios of escalation ≥50% resulted in higher rates of transmural remission (34.2% vs. 15.1%, p < 0.001). The effect was more pronounced in patients with early disease (50.0% vs. 12.0%, p = 0.003). In multivariate analysis, a treatment escalation ratio ≥50% (OR 3.46, 95% CI 1.67-7.17, p = 0.001) and early disease intervention (OR 3.24, 95% CI 1.12-9.34, p = 0.030) were independent predictors of achieving transmural remission.

CONCLUSION

Tight-monitoring and reactive treatment escalation increase the rates of transmural remission in CD. Intervention in early disease further improves these results.

Pan-Enteric Capsule Endoscopy: Current Applications and Future Perspectives

Background

The role of capsule endoscopy in the evaluation of the small bowel is well established, and current guidelines position it as a first-line test in a variety of clinical scenarios. The advent of double-headed capsules further enabled the endoscopic assessment of colonic mucosa and the opportunity for a one-step noninvasive examination of the entire bowel (pan-enteric capsule endoscopy [PCE]).

Summary

We reviewed the technical procedure and preparation of patients for PCE, as well as its current clinical applications and future perspectives. In non-stricturing and non-penetrating Crohn's disease affecting the small bowel and colon, PCE monitors disease activity by assessing mucosal healing, a major treatment outcome, with a higher diagnostic yield than cross-sectional imaging or conventional colonoscopy. Also in ulcerative colitis, double-headed capsules have been used to monitor disease activity noninvasively. Currently, validated scoring systems have been specifically devised for these double-headed capsules and permit a standardized assessment of the inflammatory burden. In suspected mid-lower digestive bleeding, some exploratory studies have demonstrated the feasibility and high diagnostic yield of PCE, which may work as a filter indicating which patients may benefit of further invasive procedures, namely, for planned hemostatic procedures. The possibility of using PCE is also discussed in the context of polyposis syndromes with simultaneous involvement of the small intestine and colon.

Key Messages

PCE is a feasible, effective, and safe diagnostic procedure to evaluate the small bowel and colon. It has been increasingly explored in the setting of inflammatory bowel diseases and, more recently, in suspected mid-lower digestive bleeding. PCE is expected to reduce the demand for invasive procedures and expand the scope of noninvasive intestinal evaluation in the coming future.

Proactive Infliximab Monitoring Improves the Rates of Transmural Remission in Crohn's Disease: A Propensity Score-Matched Analysis

BACKGROUND

Few patients can reach transmural remission in Crohn's disease (CD) with currently available therapies. Proactive optimization of infliximab (IFX) based on trough levels may potentially improve these results.

METHODS

Retrospective cohort study including consecutive CD patients starting treatment with IFX. Rates of transmural remission were compared between patients with and without therapeutic drug monitoring (target level: 5-7 µg/mL). A propensity score-matched analysis was performed to adjust for potential confounders.

RESULTS

A total of 195 CD patients were included, 57.9% receiving proactive therapeutic drug monitoring. The rates of transmural remission were higher in patients under proactive therapeutic drug monitoring (37.2% vs 18.3%; P = .004) with similar results in the propensity score-matched analysis (34.2% vs 17.1%; P = .025). In multivariate analysis, proactive therapeutic drug monitoring was independently associated with transmural remission (odds ratio, 2.95; 95% confidence interval, 1.44-6.06; P = .003).

CONCLUSIONS

Proactive optimization of IFX based on trough levels increases the rates of transmural remission in CD.

Impact of inbreeding and genetic parameter estimates for seminal traits in Lusitano horses

The objectives of this study were to establish baseline information for seminal traits in Lusitano stallions, to assess the impact of inbreeding, interval between collections and age on semen quality during the breeding and non-breeding seasons, and to estimate the corresponding genetic parameters. A total of 2129 ejaculates by 146 Lusitano stallions used for artificial insemination, obtained from four equine reproduction centers distributed throughout Portugal, over a period of 14 years (2008-2021), were included in the study. The seminal traits analyzed, and the corresponding means and standard deviations, were gel-free volume (56.95 ± 28.76 mL), concentration (186.48 ± 104.68 × 106), motility (64.1 ± 16.9%), total number of spermatozoa (TNS) (9.271 ± 4.956 × 109) and total number of motile spermatozoa per ejaculate (TNMS) (5.897 ± 3.587 × 109). These results are in the normal range of values described for other breeds. In the stallions analyzed, the mean value for the inbreeding coefficient was 7.93 ± 5.29%, and for age it was 12.70 ± 6.83 years. A significant decline in sperm concentration, motility, TNS, and TNMS was observed as inbreeding increased. The season also influenced sperm concentration, motility, TNS and TNMS, with the highest values observed during the breeding season. When considering the impact of age on Lusitano seminal parameters, results showed a nonlinear relationship, with a positive effect until 18 years of age for volume, motility, TNS and TNMS and a negative effect after this age, with a slow decrease. However, age had a markedly negative effect on sperm concentration. The interval between semen collections only affected (P < 0.05) sperm motility, with a regression coefficient of +1.89 ± 2.17% per additional day. Genetic parameters were estimated with an Animal Model, and the estimated heritability (repeatability) was 0.27 (0.35) for volume, 0.02 (0.38) for sperm concentration, 0.24 (0.44) for motility, 0.29 (0.39) for TNS and 0.41 (0.41) for TNMS. These results suggest that it is possible to improve semen quality by selection and that the properties of semen produced by a stallion tend to remain consistent throughout its lifetime. Furthermore, the impact of inbreeding should be taken into consideration when selecting Lusitano stallions for fertility.

Would surgical Apgar score be useful to predict postoperative complications after proximal femoral fracture surgery? - A retrospective cohort study

BACKGROUND

The surgical Apgar score (SAS) is a perioperative risk evaluation score, which considers intraoperative minimum heart rate, minimum mean arterial pressure and estimated blood loss. Although validated in multiple surgical fields, SAS remains quite controversial in the orthopedic one. The main purpose of this study was to investigate if SAS relates with the occurrence of complications during the first 30-days after proximal femoral fracture surgery.

METHODS

Retrospective study including all consecutive patients submitted to proximal femoral fracture surgery between January and July 2019. Patients with no information about SAS were excluded. Patients were divided in two groups, based on the occurrence of complications during the first 30 post-operative days and their SAS calculated. Receiver operating characteristic (ROC) curves were used to assess SAS power as a predictive model of complications.

RESULTS

Forty-two percent (n = 76) of the 181 patients included in the study developed complications during the first 30 postoperative days. Eight patients (4,4%) died during that period. The patient's mean age was 79 years and 30,9% (n = 56) were men. Heart failure, pacemaker use, chronic kidney disease, chronic obstructive pulmonary disease and dementia were significantly associated with post-operative morbidity. There was no significant correlation between SAS and the occurrence of complications during the first 30 postoperative days. The AUC of SAS as a predictive model for postoperative complications after proximal femoral fracture surgery was 0,522, being insufficient to be considered an accepted model of prediction.

CONCLUSION

Based on this study, we conclude that SAS is not predictive of the development of complications in the first 30 post-operative days in patients submitted to proximal femoral fracture surgery. However, other clinical factors have been identified as associated with postoperative morbidity. In the future, prospective-based studies with higher samples may better clarify the role of SAS in this context.

Swiss public health measures associated with reduced SARS-CoV-2 transmission using genome data

Genome sequences from evolving infectious pathogens allow quantification of case introductions and local transmission dynamics. We sequenced 11,357 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes from Switzerland in 2020-the sixth largest effort globally. Using a representative subset of these data, we estimated viral introductions to Switzerland and their persistence over the course of 2020. We contrasted these estimates with simple null models representing the absence of certain public health measures. We show that Switzerland's border closures decoupled case introductions from incidence in neighboring countries. Under a simple model, we estimate an 86 to 98% reduction in introductions during Switzerland's strictest border closures. Furthermore, the Swiss 2020 partial lockdown roughly halved the time for sampled introductions to die out. Last, we quantified local transmission dynamics once introductions into Switzerland occurred using a phylodynamic model. We found that transmission slowed 35 to 63% upon outbreak detection in summer 2020 but not in fall. This finding may indicate successful contact tracing over summer before overburdening in fall. The study highlights the added value of genome sequencing data for understanding transmission dynamics.

Proactive infliximab is more effective than vedolizumab in inducing fecal calprotectin remission in inflammatory bowel disease

BACKGROUND

Current evidence suggests vedolizumab (VDZ) may be as effective as Infliximab (IFX) in inflammatory bowel disease. It is unknown if proactive therapeutic drug monitoring (PTDM) of IFX may improve these results.

METHODS

Case-control study including consecutive patients with primary response to conventional IFX (n = 70), proactive IFX (n = 148), and VDZ (n = 95). PTDM was performed at week 14 and every other infusion, aiming at a trough level between 5 and 10 µg/ml. The primary outcome was fecal calprotectin (Fc) remission (<250 µg/g) at 1 year of treatment. Secondary outcomes included Fc remission at week 14 (proactive IFX/VDZ), clinical remission, treatment discontinuation, hospitalization, and surgery at 1-year of follow-up.

RESULTS

Proactive IFX was superior to conventional IFX and VDZ in inducing Fc remission at 1-year (69.4% vs 47.1% vs 37.9%, p = .003 and p < .001). Results remained significant in biologic naïve patients (70.8% vs 44.4% vs 51.4%, p = .001 and p = .043) but comparisons between conventional IFX and VDZ were not significant (p = .265 and p = .664). In multivariate analysis correcting for prior biologic exposure, proactive IFX was more effective than conventional IFX (OR 2.480 95%CI [1.367-4.499], p = .003) and VDZ (OR 3.467 95%CI [1.578-7.617], p = .002) in inducing Fc remission. Amongst secondary outcomes, only clinical remission was significant between proactive IFX and VDZ in the overall cohort (80.4% vs 55.8%, p < .001) and in biologic naïve patients (80.2% vs 62.9%, p = .043). Fc remission at 1-year was associated with better results in most secondary outcomes.

CONCLUSION

Proactive IFX was superior to VDZ in inducing Fc remission at 1-year, which was associated with improved clinical outcomes.SUMMARYCurrent evidence suggests that vedolizumab may be as effective as Infliximab in the treatment of patients with inflammatory bowel disease.There have been no studies comparing vedolizumab with proactively optimized Infliximab based on trough levels.We confirm that conventional IFX is as effective as vedolizumab but proactive IFX appears superior to vedolizumab in inducing fecal calprotectin remission.Fecal calprotectin remission associates with better clinical outcomes.

Influence of Spinal Shock on the Neurorehabilitation of ANNPE Dogs

Acute noncompressive nucleus pulposus extrusion (ANNPE) is related to contusive spinal cord injuries, and dogs usually appear to be exercising vigorously at the time of onset. ANNPE has a characteristic peracute onset of clinical signs during exercise or following trauma, with non-progressive signs during the first 24 h and possibly signs of spinal shock. The main aim was to assess if the presence of spinal shock affects the neurorehabilitation outcomes of ANNPE dogs. This prospective controlled cohort clinical study was conducted at the Arrábida Rehabilitation Center. All of the dogs had T3−L3 injuries and were paraplegic/monoplegic with/without nociception, the study group (n = 14) included dogs with ANNPE spinal shock dogs, and the control group (n = 19) included ANNPE dogs without spinal shock. The study group was also evaluated using a new scale—the Spinal Shock Scale (SSS)—and both groups were under the same intensive neurorehabilitation protocol. Spinal shock was a negative factor for a successful outcome within less time. SSS scores > 4 required additional hospitalization days. The protocol was safe, tolerable, and feasible and accomplished 32% ambulation within 7 days, 29% in 14 days, and 29% in 30 days. The results were better than those obtained in previous studies—94% at 60 days—and 75% of the dogs without nociception recovered ambulation. Long-term follows-ups carried out 4 years later revealed a positive evolution.

Proactive therapeutic drug monitoring is more effective than conventional management in inducing fecal calprotectin remission in inflammatory bowel disease

BACKGROUND

Proactive therapeutic drug monitoring (pTDM) may improve treatment outcomes in inflammatory bowel disease.

AIMS AND METHODS

We compared 135 patients following a prospective pTDM protocol aiming at an infliximab trough level (IFXTL) between 5 and 10 μg/ml with sequential measurements of Fc, with 108 patients from a retrospective group under conventional management. We evaluated the rates of Fc remission (<250 μg/g) and other clinical outcomes at 2-year of follow-up.

RESULTS

pTDM associated with higher rates of Fc remission (69.6% vs. 50.0%; P = 0.002), and steroid-free clinical remission (78.4% vs. 55.2%, P = 0.028) with a trend for clinical remission (79.3% vs. 68.5%, P = 0.075). There was no difference in treatment discontinuation (P = 0.195), hospitalization (P = 0.156), and surgery (P = 0.110). Higher IFXTL associated with Fc remission at week 14 (6.59 vs. 2.96 μg/ml, P < 0.001), and at the end of follow-up (8.10 vs. 5.03 μg/ml, P = 0.001). In patients reaching Fc remission after week 14, IFXTL increased from week 14 to the end of follow-up (2.71 vs. 8.54 μg/ml, P < 0.001). Fc remission associated with higher rates of clinical (85.8% vs. 56.8% P < 0.001) and steroid-free clinical remission (86.9% vs. 50.0% P < 0.001), lower IFX discontinuation (8.8% vs. 36.8%, P < 0.001), and hospitalization (13.5% vs. 33.7%, P < 0.001), without significance for surgery (6.1% vs. 12.6%, P = 0.101).

CONCLUSION

pTDM was more effective than conventional management in inducing Fc remission which was associated with improved outcomes.

αIIbβ3 variants in ten families with autosomal dominant macrothrombocytopenia: Expanding the mutational and clinical spectrum

Background

Rare pathogenic variants in either the ITGA2B or ITGB3 genes have been linked to autosomal dominant macrothrombocytopenia associated with abnormal platelet production and function, deserving the designation of Glanzmann Thrombasthenia-Like Syndrome (GTLS) or ITGA2B/ITGB3-related thrombocytopenia.

Objectives

To describe a series of patients with familial macrothrombocytopenia and decreased expression of αIIbβ3 integrin due to defects in the ITGA2B or ITGB3 genes.

Methods

We reviewed the clinical and laboratory records of 10 Portuguese families with GTLS (33 patients and 11 unaffected relatives), including the functional and genetic defects.

Results

Patients had absent to moderate bleeding, macrothrombocytopenia, low αIIbβ3 expression, impaired platelet aggregation/ATP release to physiological agonists and low expression of activation-induced binding sites on αIIbβ3 (PAC-1) and receptor-induced binding sites on its ligand (bound fibrinogen), upon stimulation with TRAP-6 and ADP. Evidence for constitutive αIIbβ3 activation, occurred in 2 out of 9 patients from 8 families studied, but also in 2 out of 12 healthy controls. We identified 7 missense variants: 3 in ITGA2B (5 families), and 4 in ITGB3 (5 families). Three variants (αIIb: p.Arg1026Trp and p.Arg1026Gln and β3: p.Asp749His) were previously reported. The remaining (αIIb: p.Gly1007Val and β3: p.Thr746Pro, p.His748Pro and p.Arg760Cys) are new, expanding the αIIbβ3 defects associated with GTLS. The integration of the clinical and laboratory data allowed the identification of two GTLS subgroups, with distinct disease severity.

Conclusions

Previously reported ITGA2B and ITGB3 variants related to thrombocytopenia were clustered in a confined region of the membrane-proximal cytoplasmic domains, the inner membrane clasp. For the first time, variants are reported at the outer membrane clasp, at the transmembrane domain of αIIb, and at the membrane distal cytoplasmic domains of β3. This is the largest single-center series of inherited macrothrombocytopenia associated with αIIbβ3 variants published to date.

An Online Influenza Surveillance System for Primary Care Workers in Switzerland: Observational Prospective Pilot Study

Background

A better understanding of the influenza epidemiology among primary care workers could guide future recommendations to prevent transmission in primary care practices. Therefore, we designed a pilot study to assess the feasibility of using a work-based online influenza surveillance system among primary care workers. Such an approach is of particular relevance in the context of the coronavirus disease (COVID-19) pandemic, as its findings could apply to other infectious diseases with similar mechanisms of transmission.

Objective

This study aims to determine the feasibility of using a work-based online influenza surveillance system for primary care workers in Switzerland.

Methods

Physicians and staff of one walk-in clinic and two selected primary care practices were enrolled in this observational prospective pilot study during the 2017-2018 influenza season. They were invited to record symptoms of influenza-like illness in a weekly online survey sent by email and to self-collect a nasopharyngeal swab in case any symptoms were recorded. Samples were tested by real-time polymerase chain reaction for influenza A, influenza B, and a panel of respiratory pathogens.

Results

Among 67 eligible staff members, 58% (n=39) consented to the study and 53% (n=36) provided data. From the time all participants were included, the weekly survey response rate stayed close to 100% until the end of the study. Of 79 symptomatic episodes (mean 2.2 episodes per participant), 10 episodes in 7 participants fitted the definition of an influenza-like illness case (attack rate: 7/36, 19%). One swab tested positive for influenza A H1N1 (attack rate: 3%, 95% CI 0%-18%). Swabbing was considered relatively easy.

Conclusions

A work-based online influenza surveillance system is feasible for use among primary care workers. This promising methodology could be broadly used in future studies to improve the understanding of influenza epidemiology and other diseases such as COVID-19. This could prove to be highly useful in primary care settings and guide future recommendations to prevent transmission. A larger study will also help to assess asymptomatic infections.

Proactive Infliximab Drug Monitoring Is Superior to Conventional Management in Inflammatory Bowel Disease

BACKGROUND

Increasing evidence supports the use of reactive therapeutic drug monitoring (TDM) in Crohn's disease (CD) and ulcerative colitis (UC) following secondary loss of response. It is still unknown if proactive TDM can improve clinical outcomes.

METHODS

Consecutive patients completing infliximab (IFX) induction therapy were prospectively allocated into a proactive TDM protocol (pTDM). Before the fourth infusion and every 2 infusions, IFX trough levels and antidrug antibodies were measured using a drug-sensitive assay (Theradiag, Lisa Tracker). Treatment was proactively escalated aiming at an IFX trough level between 3 and 7 ug/mL (CD) and 5 and 10 ug/mL (UC). A retrospective cohort treated with IFX but without TDM served as the reference group. End points included the need for surgery, hospitalization, treatment discontinuation, and mucosal healing at 2 years of follow-up.

RESULTS

Two hundred five patients were included, 56 in the proactive regimen. Treatment escalation was more common in pTDM patients (76.8% vs 25.5%; P < 0.001), who also required less surgery (8.9% vs 20.8%; P = 0.032) and presented higher rates of mucosal healing (73.2% vs 38.9%; P < 0.0001). Proactive TDM significantly decreased the odds of reaching any unfavorable outcome (odds ratio, 0.358; 95% confidence interval, 0.188-0.683; P = 0.002).

CONCLUSIONS

Proactive TDM is associated with fewer surgeries and higher rates of mucosal healing than conventional non-TDM-based management.

Genetic and Environmental Factors Influencing Gestation Length in Lusitano Horses

Breeding and parturition records collected over a period of 35 years in the Alter Real stud of Lusitano horses were used to calculate gestation length (GL). The 1027 gestations by 209 mares mated to 60 stallions had a mean GL of 338.1 ± 9.26 days. The mixed model analysis of variance indicated that the sex of the foal and inbreeding of the dam and foal had no significant effect on GL (P > .05). On the other hand, GL increased linearly with mare age, with an estimated regression coefficient of 0.155 ± 0.069 days/year (P < .05). Year and conception month affected GL (P < .05), with longer gestations observed when breeding occurred between January and April, followed by a decline of about 5 and 10 days in GL of mares bred in May and in June-July, respectively. Important differences were observed between stallions (P < .05), with most stallions resulting in a distribution of GL in an interval of ±5 days. The inclusion of the mare as a random effect in the mixed model resulted in an estimated repeatability of GL of 0.427, indicating that mares tend to be regular in having long or short gestations across their lifetime. Variance components estimated in an Animal Model resulted in heritability estimates of 0.39 for maternal genetic effects and 0.19 for direct genetic effects, with no association between the two components. Overall, the mare seems to have the major genetic influence on GL in Lusitano horses, but environmental factors, such as month of conception and also the age of the mare, have a noticeable effect.

Antigen Extraction and B Cell Activation Enable Identification of Rare Membrane Antigen Specific Human B Cells

Determining antigen specificity is vital for understanding B cell biology and for producing human monoclonal antibodies. We describe here a powerful method for identifying B cells that recognize membrane antigens expressed on cells. The technique depends on two characteristics of the interaction between a B cell and an antigen-expressing cell: antigen-receptor-mediated extraction of antigen from the membrane of the target cell, and B cell activation. We developed the method using influenza hemagglutinin as a model viral membrane antigen, and tested it using acetylcholine receptor (AChR) as a model membrane autoantigen. The technique involves co-culturing B cells with adherent, bioorthogonally labeled cells expressing GFP-tagged antigen, and sorting GFP-capturing, newly activated B cells. Hemagglutinin-specific B cells isolated this way from vaccinated human donors expressed elevated CD20, CD27, CD71, and CD11c, and reduced CD21, and their secreted antibodies blocked hemagglutination and neutralized viral infection. Antibodies cloned from AChR-capturing B cells derived from patients with myasthenia gravis bound specifically to the receptor on cell membrane. The approach is sensitive enough to detect antigen-specific B cells at steady state, and can be adapted for any membrane antigen.

Predicting the Course of Disease in Hospitalized Patients With Acute Severe Ulcerative Colitis

BACKGROUND

Up to one-third of patients with acute severe ulcerative colitis (ASUC) will fail intravenous steroid (IVS) treatment, requiring rescue therapy with cyclosporin (Cys), infliximab (IFX), or colectomy. Although several scores for predicting response to IVS exist, formal comparison is lacking.

METHODS

We performed a single-center retrospective analysis including 489 patients with ulcerative colitis. In patients with ASUC, the Mayo endoscopic subscore and the Oxford, Edinburgh, and Lindgren scores were assessed. Outcomes included IVS failure, need for rescue medical therapy, and surgery.

RESULTS

One hundred twelve patients presented with ASUC. Forty-two percent showed an incomplete or absent response to IVS, 28.6% received rescue therapy (22 with IFX, 10 with Cys, and 1 with sequential treatment), and 26.8% required surgery. The Lindgren score showed the highest performance in predicting IVS failure (are under the curve [AUC], 0.856; 95% confidence interval [CI], 0.784-0.928), need for medical rescue therapy (AUC, 0.826; 95% CI, 0.749-0.902), and surgery (AUC, 0.836; 95% CI, 0.712-0.960; all P < 0.01).

CONCLUSIONS

In our series, the Lindgren score was superior to the Mayo, Oxford, and Edinburgh scores in predicting major clinical outcomes in ASUC.

Age-related changes in social decision-making: An electrophysiological analysis of unfairness evaluation in the Ultimatum Game

This study examines age-related differences in behavioral and neural responses to unfairness. Our sample was composed of younger, middle-aged, and older adults, who performed the Ultimatum Game in the proposer role, and in the respondent role during an EEG recording. We administered neurocognitive tests to identify whether patterns in decision-making are associated with age-related changes in cognition. Despite the worse performance in measures of executive functioning, older adults had the best economic strategy by accepting more unfair offers than younger and middle-aged adults. Regarding electrophysiological results, while younger adults showed higher medial frontal negativity (MFN) amplitudes after unfair than after fair offers, middle-aged and older adults had similar amplitudes after both conditions. Our results suggest that aging may be accompanied by an insensitivity to unfairness, which may underlie their higher rates of unfair offers acceptance.

Systemic sclerosis and sarcoidosis: a rare case of chronic intestinal pseudo-obstruction

The coexistence of systemic sclerosis (SSc) and sarcoidosis is an extremely rare phenomenon; some studies question its existence. We report the case of a male with a diagnosis of sarcoidosis that was admitted due to abdominal distension and pain. After a thorough investigation, he was diagnosed with severe chronic intestinal pseudo-obstruction as a manifestation of SSc.

The effect of aging on the (mis)perception of intentionality - an ERP study

Despite the accumulated knowledge on moral decision-making in the early stages of development, empirical evidence is still limited in the old-aged adults. The current study contributes to unveil the neural correlates of judgments of moral transgressions as a function of aging, by examining the temporal dynamics of neural activation elicited by intentional and accidental harmful actions in three groups of healthy participants: young adults (18-35), adults (40-55), and older adults (60-75). Older adults were slower and less accurate in rating intentionality, compared to the younger groups. In ERP analysis, the older group showed increased P2 amplitude, which was predicted by poorer performance on neuropsychological tests. Reduced amplitudes were found on critical ERP components to moral cognition (N2 and LPP), namely while processing intentional harmful scenarios. Older adults seem to allocate more attentional resources (P2) to the task, probably to compensate the age-related decline in executive functioning, while younger groups show a pronounced negativity while detecting harm (N2) and increased neural activation to encode the intentions behind the acts (LPP).

The use of a segmental endoscopic score may improve the prediction of clinical outcomes in acute severe ulcerative colitis

BACKGROUND

Acute severe colitis (ASC) remains a challenging complication of ulcerative colitis. The early identification of patients who will not respond to optimal therapy is warranted. Increasing evidence suggests that endoscopy may play a role in predicting important outcomes in acute severe colitis.

METHODS

The endoscopic activity of consecutive patients with acute severe colitis was evaluated using the Mayo endoscopic sub-score (Mayo) and the ulcerative colitis endoscopic index of severity (UCEIS). Two segmental indexes were also produced by summing the scores of the rectum and sigmoid (seg-Mayo and seg-UCEIS, respectively). Endpoints included the need for salvage therapy with infliximab or cyclosporine, refractoriness to corticosteroids, and colectomy.

RESULTS

Of one hundred and eight patients enrolled in the study, 60 (55.6%) were male; with a median age of 34.5 years (range 15-80). All patients received intravenous steroids. Fifty-nine patients (55.6%) showed an incomplete or absent response to steroids, 35 patients (34.3%) received salvage therapy with infliximab or cyclosporine and 38 patients (33.3%) were colectomized during the index hospitalization or within the first year of follow-up. All scores were able to predict the need for surgery, but only the seg-UCEIS significantly predicted refractoriness to steroids.

CONCLUSIONS

There was a strong correlation between endoscopic severity and unfavorable outcomes. The UCEIS outperformed the Mayo endoscopic sub-score in all important outcomes. Segmental scoring further improved the performance of the UCEIS.

Clinical performance of an infliximab rapid quantification assay

BACKGROUND

Therapeutic drug monitoring (TDM)-based algorithms can be used to guide infliximab (IFX) adjustments in inflammatory bowel disease (IBD) patients. This study aimed to explore a rapid IFX-quantification test from a clinical perspective.

METHODS

This manuscript describes a prospective cohort study involving 110 ulcerative colitis (UC) patients on the maintenance phase of IFX. IFX trough levels were quantified using a rapid quantification assay and a commonly-used reference kit.

RESULTS

Irrespective of the assay used to measure IFX, its through levels were statistically different between patients with and without endoscopic remission (Mayo endoscopic score = 0), as well as between patients stratified by their faecal calprotectin (FC) levels. Despite the fact that the two methods correlated well with each other [Spearman's rank correlation coefficient = 0.843, p < 0.001; intraclass correlation coefficients = 0.857, 95% confidence interval (CI): 0.791-0.903], there was a discernible systematic variation; values obtained with the reference kit were on average 2.62 units higher than those obtained with the rapid assay. Notwithstanding, 3 µg/ml was shown to be an acceptable cut-off to assess endoscopic status and inflammatory burden levels using both assays. The percentage of patients that had a positive outcome when the IFX concentration measured by the rapid assay ranked above 3 µg/ml was 88% both for a Mayo endoscopic score ⩽ 1 and for an FC concentration <250 µg/g.

CONCLUSIONS

Based on this study, we concluded that using the rapid IFX assessment system with a 3 µg/ml threshold is a reliable alternative to the time-consuming enzyme-linked immunosorbent assays in patients on the maintenance phase of IFX.

Calprotectin and the Magnitude of Antibodies to Infliximab in Clinically-stable Ulcerative Colitis Patients are More Relevant Than Infliximab Trough Levels and Pharmacokinetics for Therapeutic Escalation

Although infliximab (IFX) is an efficient therapy for ulcerative colitis (UC) patients, a considerably high rate of therapeutic failures still occurs. This study aimed at a better understanding of IFX pharmacokinetics and pharmacodynamics among clinically-asymptomatic UC patients. This was a multicentric and prospective study involving 65 UC patients in the maintenance phase of IFX therapy. There were no significant differences between patients with positive and negative clinical, endoscopic and histological outcomes concerning their IFX trough levels (TLs), area under the IFX concentration vs. time curve (AUC), clearance and antibodies to infliximab (ATI) levels. However, the need to undergo therapeutic escalation later in disease development was significantly associated with higher ATI levels (2.62μg/mL vs. 1.15μg/mL, p=0.028). Moreover, and after adjusting for disease severity, the HR (hazard ratio) for therapeutic escalation was significantly decreased for patients with an ATI concentration below 3μg/mL (HR=0.119, p=0.010), and increased for patients with fecal calprotectin (FC) level above 250μg/g (HR=9.309, p=0.018). In clinically-stable UC patients, IFX pharmacokinetic features cannot predict therapeutic response on a short-term basis. However, high levels of ATIs or FC may be indicative of a future therapeutic escalation.

Comparative analysis of viral shedding in pediatric and adult subjects with central nervous system-associated enterovirus infections from 2013 to 2015 in Switzerland

BACKGROUND

Several enterovirus (EV) genotypes can result in aseptic meningitis, but their routes of access to the central nervous system remain to be elucidated and may differ between the pediatric and adult populations.

OBJECTIVE

To assess the pattern of viral shedding in pediatric and adult subjects with acute EV meningitis and to generate EV surveillance data for Switzerland.

STUDY DESIGN

All pediatric and adult subjects admitted to the University Hospitals of Geneva with a diagnosis of EV meningitis between 2013 and 2015 were enrolled. A quantitative EV real-time reverse transcriptase (rRT)-PCR was performed on the cerebrospinal fluid (CSF), blood, stool, urine and respiratory specimens to assess viral shedding and provide a comparative analysis of pediatric and adult populations. EV genotyping was systematically performed.

RESULTS

EV positivity rates differed significantly between pediatric and adult subjects; 62.5% of pediatric cases (no adult case) were EV-positive in stool and blood for subjects for whom these samples were all collected. Similarly, the EV viral load in blood was significantly higher in pediatric subjects. Blood C-reactive protein levels were lower and the number of leucocytes/mm³ in the CSF were higher in non-viremic than in viremic pediatric subjects, respectively. A greater diversity of EV genotypes was observed in pediatric cases, with a predominance of echovirus 30 in children ≥3 years old and adults.

CONCLUSION

In contrast to adults, EV-disseminated infections are predominant in pediatric subjects and show different patterns of EV viral shedding. This observation may be useful for clinicians and contribute to modify current practices of patient care.

Detection of anti-infliximab antibodies is impacted by antibody titer, infliximab level and IgG4 antibodies: a systematic comparison of three different assays

BACKGROUND

There is scant information on the accuracy of different assays used to measure anti-infliximab antibodies (ADAs), especially in the presence of detectable infliximab (IFX). We thus aimed to evaluate and compare three different assays for the detection of IFX and ADAs and to clarify the impact of the presence of circulating IFX on the accuracy of the ADA assays.

METHODS

Blood samples from 79 ulcerative colitis (UC) patients treated with infliximab were assessed for IFX levels and ADAs using three different assays: an in-house assay and two commercial kits, Immundiagnostik and Theradiag. Sera samples with ADAs and undetectable levels of IFX were spiked with exogenous IFX and analyzed for ADAs.

RESULTS

The three assays showed 81-96% agreement for the measured IFX level. However, the in-house assay and Immundiagnostik assays detected ADAs in 34 out of 79 samples, whereas Theradiag only detected ADAs in 24 samples. Samples negative for ADAs with Theradiag, but ADA-positive in both the in-house and Immundiagnostik assays, were positive for IFX or IgG4 ADAs. In spiking experiments, a low concentration of exogenous IFX (5 µg/ml) hampered ADA detection with Theradiag in sera samples with ADA levels of between 3 and 10 µg/ml. In the Immundiagnostik assay detection interference was only observed at concentrations of exogenous IFX higher than 30 µg/ml. However, in samples with high levels of ADAs (>25 µg/ml) interference was only observed at IFX concentrations higher than 100 µg/ml in all three assays. Binary (IFX/ADA) stratification of the results showed that IFX+/ADA- and IFX-/ADAs+ were less influenced by the assay results than the double-positive (IFX+/ADAs+) and double-negative (IFX-/ADAs-) combination.

CONCLUSIONS

All three methodologies are equally suitable for measuring IFX levels. However, erroneous therapeutic decisions may occur when patients show double-negative (IFX-/ADAs-) or double-positive (IFX+/ADAs+) status, since agreement between assays is significantly lower in these circumstances.

Proactive therapeutic drug monitoring of infliximab: a comparative study of a new point-of-care quantitative test with two established ELISA assays

BACKGROUND

Therapeutic drug monitoring is a powerful strategy known to improve the clinical outcomes and to optimise the healthcare resources in the treatment of autoimmune diseases. Currently, most of the methods commercially available for the quantification of infliximab (IFX) are ELISA-based, with a turnaround time of approximately 8 h, and delaying the target dosage adjustment to the following infusion.

AIM

To validate the first point-of-care IFX quantification device available in the market - the Quantum Blue Infliximab assay (Buhlmann, Schonenbuch, Switzerland) - by comparing it with two well-established methods.

METHODS

The three methods were used to assay the IFX concentration of spiked samples and of the serum of 299 inflammatory bowel diseases (IBD) patients undergoing IFX therapy.

RESULTS

The point-of-care assay had an average IFX recovery of 92%, being the most precise among the tested methods. The Intraclass Correlation Coefficients of the point-of-care IFX assay vs. the two ELISA-based established methods were 0.889 and 0.939. Moreover, the accuracy of the point-of-care IFX compared with each of the two reference methods was 77% and 83%, and the kappa statistics revealed a substantial agreement (0.648 and 0.738).

CONCLUSIONS

The Quantum Blue IFX assay can successfully replace the commonly used ELISA-based IFX quantification kits. This point-of-care IFX assay is able to deliver the results within 15 min makes it ideal for an immediate target concentration adjusted dosing. Moreover, it is a user-friendly desktop device that does not require specific laboratory facilities or highly specialised personnel.

Spontaneous intramural hematoma of the colon

A 73-year-old man was admitted to our clinic with sudden left quadrant abdominal pain and hematochezia. There was no history of trauma. He denied other symptoms or taking off-the-counter medication. His medical history was relevant for ischemic and aortic-mitral valve disease with prosthetic valves for which he was medicated with aspirin and warfarin. On physical examination the patient presented normal vital signs with tenderness on palpation of the left side of the abdomen. Laboratory tests revealed moderate anemia (10.8 g/dl) and thrombocytopenia (135.000x10^9 U/L) with therapeutic international normalized ratio (2.53). Colonoscopy revealed an extensive area of erythematous and bluish mucosa with an apparent torsion of the proximal descending colon around a volumous hematoma measuring 6.5x3 cm (Figure 1 A-C). Urgent abdominal CT confirmed the presence of a large intramural hematoma of the descending colon (Figure 2 A-B). A conservative approach was adopted with temporary suspension of anticoagulation. Given the high thrombotic risk, abdominal ultrasound was performed after 72 hours showing considerable reduction in the size of the hematoma. Anti-coagulation was then resumed without complications. One month later, colonoscopy was repeated showing complete healing of the mucosa. The increasing use of anti-aggregating and anti-coagulant therapy, especially in elderly patients, explains the increasing incidence of bleeding events seen in this population. However, gastrointestinal hematomas are estimated to occur in only 1 for every 250.000 anti-coagulated patients. Diagnosis is based on characteristic radiologic findings. While most parietal hematomas can be approached conservatively, surgery is indicated in the presence of complications or persistence of the hematoma.

Hospital surveillance of influenza strains: a concordant image of viruses identified by the Swiss Sentinel system?

Background

The Swiss Sentinel system for influenza virus surveillance reports influenza‐like illness in the community through a network of primary care practitioners, but the epidemiologic, demographic, and virological characterization may differ from that observed in hospitalized patients with influenza.

Objective

To compare demographic and virological data from hospital influenza cases with Sentinel system data during the 2014–2015 season.

Methods

We included 2623 in‐ and outpatients with a screening request for influenza A/B in a university teaching hospital in Geneva, Switzerland, and 933 participants from the Swiss Sentinel surveillance system and compared the demographic and virological data of the two populations, including the respective distribution of influenza subtypes, and conducted a phylogenetic comparison at the HA1 level of influenza viruses recovered in community and hospital cases.

Results

There were similar proportions of influenza strains recovered in the hospital and in the community (H3N2, 57.1% and 56.9%; H1N1pdm09, 15.5% and 14.2%; B, 27.4% and 28.8%, respectively). HA1 sequence analysis confirmed that all three strains were genetically similar between the two populations. During this particular season, influenza cases were detected earlier in the hospital than in the Sentinel system.

Conclusions

Although an influenza surveillance system based on the community can predict the type of influenza strains that will be associated with hospitalizations, it fails to estimate the potential virulence of circulating strains. Further, the population characteristics in the community differ from those in hospitalized patients. This suggests that any national influenza surveillance system should include both community‐ and hospital‐based surveys.

[Portuguese Consensus on the Diagnosis, Prevention and Treatment of Anaemia in Inflammatory Bowel Disease]

INTRODUCTION

Anaemia can be considered the most common extra-intestinal manifestation in inflammatory bowel disease. Nevertheless, anaemia is often under-diagnosed and under-treated both in adults and children with inflammatory bowel disease. Herein, we report the consensus statements on the management of anaemia in inflammatory bowel disease developed by the Portuguese Working Group on Inflammatory Bowel Disease (known as Grupo de Estudo da Doença Inflamatória Intestinal - GEDII) to aid clinicians in daily management of inflammatory bowel disease patients.

MATERIAL AND METHODS

A comprehensive literature review was conducted in order to prepare consensus statements on the following topics: (1) prevalence and diagnosis of anaemia in inflammatory bowel disease, (2) iron supplementation for the prevention of anaemia in inflammatory bowel disease and (3) treatment of anaemia in inflammatory bowel disease. The final statements for each topic were discussed at a consensus meeting and rated according to the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence.

CONSENSUS

It was concluded that anaemia has a high incidence and prevalence in inflammatory bowel disease, particularly in those with active disease and hospitalised. Patients with anaemia had decreased quality of life and frequently complained of fatigue. Absolute indications for intravenous therapy should be considered: (1) moderate to severe anaemia (haemoglobin < 10.5 g/dL) or clearly symptomatic anaemia; (2) previous intolerance to oral iron supplements; (3) inappropriate response to oral iron; (4) active severe intestinal disease; (5) need for a quick therapeutic response (e.g. surgery in the short term); (6) concomitant therapy with erythropoiesis-stimulating agent; and (7) patient's preference.

Assessment of quality in screening colonoscopy for colorectal cancer

INTRODUCTION

The effectiveness of screening colonoscopy in decreasing the incidence of colorectal cancer (CRC) is largely dependent on the detection of polyps and the quality of the procedure. Several key quality measures have been proposed to improve the effectiveness of screening colonoscopies.

AIM

To evaluate quality indicators of screening colonoscopy in a tertiary hospital.

METHODS

All CRC screening colonoscopies performed between 2005 and 2009 in a single tertiary center were reviewed for internationally accepted quality measures.

RESULTS

Of the 1545 individuals who underwent first-time screening colonoscopy 38% were male and 62% were female. The mean age of the patients was 60.4 years and the mean difference in ages was ± 10.3 years. Cecal intubation rate was 91% (1336), however ileocecal valve photo documentation was performed in only 81% (1248) colonoscopies. The quality of bowel preparation was classified as: good 76% (1171), reasonable 11% (174), and poor 13% (200). Polyp detection rate (PDR) was 33% (503). The prevalence of polyps ≥1 cm in size was 5% (82). PDR was significantly higher in men than in women (44% [260] vs 25% [243], P = 0.0001). Other factors significantly influencing PDR were quality of bowel preparation (odds ratio [OR]: 1.28, 95% confidence interval [CI]: 0.9-1.6) and age over 50 (OR: 1.9, 95% CI: 1.3-2.9). Left colonic polyps were associated with a risk ratio of 2.3 (95% CI: 1.8-2.9) of lesions in the other colonic segments compared to no polyps in the left colon. None of the colonoscopists reported withdrawal time.

CONCLUSION

Cecal intubation rate and quality of bowel preparation were suboptimal. The polyp detection rate compares favorably to accepted standards and its main determinants are male sex, age >50 years, quality of bowel preparation, and the presence of left colonic polyps.

Detection of bacterial DNA in acute and chronic cholecystitis

BACKGROUND

The incidence of bacterbilia in cholelithiasis remains controversial. The positivity of cultures ranges from 0 to 73 per cent. The aim of this study was to employ the polymerase chain reaction (PCR) to detect bacterial DNA in gallbladder bile extracted during elective laparoscopic cholecystectomy, and to compare PCR findings with those of bile culture.

METHODS

Bile samples from 84 laparoscopic cholecystectomies were collected for culture and PCR analysis.

RESULTS

Positive results for bacterbilia were found in 42 (50 per cent) of 84 patients by PCR but in only 16 patients (19 per cent) by culture (P < 0.001). Agreement between the two methods was seen in 44 samples (52 per cent), which were negative in 35 cases. Pathological examination showed chronic cholecystitis in 69 cases (82 per cent) and acute cholecystitis in 15 (18 per cent). Thirty-three (48 per cent) of the patients with chronic cholecystitis were PCR positive but only ten (14 per cent) were culture positive (P < 0.001). Only culture results correlated with findings on pathological examination (P = 0.033).

CONCLUSION

PCR is more sensitive in detecting bacterial contamination of gallbladder bile in cholecystitis than conventional culture. The clinical relevance of this high sensitivity remains unclear.

Severe gastro-oesophageal reflux disease

A 60-year-old woman with an unremarkable medical history complained of a retrosternal burning sensation, heartburn and regurgitation, with twice-monthly symptoms evolving over 10 years. Upper digestive endoscopy (UDE) showed the lower oesophageal lumen to be reduced in diameter, with bleeding, longitudinal ulcers covering the oesophageal circumference, compatible with a diagnosis of Los Angeles class D severe erosive gastro-oesophageal reflux disease. Oral pantoprazole 40 mg every 12 hours was prescribed. Symptoms of pyrosis and intermittent dysphagia resolved after 8 weeks' treatment and repeat UDE showed the terminal portion of the oesophageal lumen to be of normal calibre with the presence of a small, hardened ulcer. The patient continued to receive maintenance therapy with once-daily pantoprazole 40 mg. Effective 24-hour control of intra-oesophageal pH at levels>4 is necessary for the treatment of oesophageal acid gastric reflux; proton pump inhibitors are currently the gold standard enabling long-term symptom control and reversal of endoscopic lesions.

Survey of extended-spectrum β-lactamases in Escherichia coli isolates from a Portuguese hospital and characterisation of a novel class 1 integron (In60A) carrying the blaCTX-M-9 gene

Between November 2001 and November 2004, 231 Escherichia coli isolates resistant to beta-lactam antibiotics were identified. In 14 isolates, bla(TEM-24) (2 isolates), bla(TEM-52) (5 isolates) and bla(TEM-26) (7 isolates) were identified. In 145 E. coli isolates with the same M13 fingerprinting profile and the same resistance phenotype, the bla(CTX-M-15) gene was found in association with an insertion sequence ISEcp1. The bla(CTX-M-2) gene was identified in one E. coli isolate (290HSM), and in other E. coli isolate (246HSM) the bla(CTX-M-9) gene was contained in a new complex sul1-type class 1 integron (named In60A). This is the first report of three cefotaximases (CTX-M-15, CTX-M-2 and CTX-M-9) in E. coli isolates from a Portuguese hospital.

Hemangioma esplênico e Síndrome de Kasabach-Merritt como diagnóstico diferencial de massa abdominal do recém-nascido

Apresentamos um caso raro de hemangioma esplênico em um recém-nascido do sexo feminino, apresentando-se como massa abdominal, coagulopatia e trombocitopenia. No ato operatório observou-se uma massa tumoral vascular do pólo inferior do baço. A paciente encontra-se em acompanhamento ambulatorial. O diagnóstico e as opções de tratamento foram revistas e discutidas. Os autores revisaram a literatura sobre hemangioma esplênico em recém-nascidos e observaram ser este o terceiro caso de associação entre hemangioma esplênico e síndrome de Kasabach-Merritt. O hemangioma esplênico é uma doença rara no diagnóstico diferencial das massas abdominais em recémnascidos. O hemangioma é a neoplasia benigna mais freqüente do baço. A anemia, a trombocitopenia e a coagulopatia são vistos com freqüência em hemangiomas cavernosos grandes associados à Síndrome de Kasabach-Merritt (KMS). O hemangioma cavernoso esplênico associado com esta síndrome é extremamente raro.

Bleachability and characterization by Fourier transform infrared principal component analysis of Acetosolv pulps obtained from sugarcane bagasse

Sugarcane bagasse Acetosolv pulps were bleached by xylanase and the pulps classified by using Fourier transform infrared (FTIR) spectroscopy and principal component analysis (PCA). Pulp was treated with xylanase for 4-8 hwith stirring at 30 degrees C. Some samples were further extracted with NaOH for 1 h at 65 degrees C. FTIR spectra were recorded directly from the dried pulp samples by using the diffuse reflectance technique. Reduction in kappa number of 69% was obtained after sequence xylanase (4 h)-alkaline extraction. During bleaching the viscosity decreased only 12%. FTIR-PCA showed that the first three principal components (PCs) explained more than 90% of the total variance of the pulp spectra. PC2 x PC1 plot showed that the points related to pulps from sequence xylanase (4 h)-alkaline extraction are different from the other. This group is enlarged by plotting PC3 x PC1 or PC3x PC2 containing all pulps submitted to alkaline extraction. PC2 and PC3 are the principal factor for differentiation of the pulps. These PCs suffer influence of the ester bands (1740 and 1244 cm(-1)). On the other hand, the pulps bleached only with xylanase could not be differentiated from the nonbleached pulps.

Mathematical modeling of controlled-release kinetics of herbicides in a dynamic-water-bath system

Release of herbicides from lignin-based formulations follows a diffusion-controlled mechanism. For mathematical modeling of diffusive transport, the conventional approach is to assume sink conditions at both surfaces of polymeric matrix. This boundary condition proved to be inadequate to describe experimental data obtained in a water dynamic bath system. However, satisfactory descriptions for this system were obtained when a stagnant unstirred layer of herbicide solution was used as the boundary condition. The adequacy of the model incorporating this new boundary condition was statistically tested using the Fisher test at a confidence level of 95% and plotting the residual distribution.

Hydroxymethylation and oxidation of Organosolv lignins and utilization of the products

Organosolv lignins obtained from Eucalyptus grandis, sugarcane bagasse and Picea abies by Acetosolv, Formacell and Organocell processes were characterized, fractionated and converted to hydroxymethylated and oxidized products. The reactivity of lignins with formaldehyde did not improve significantly with the fractionation. Both eucalyptus Acetosolv (EAc) and eucalyptus Formacell (EFo) lignins retained high heterogeneity in relation to the molecular weight distribution but not in relation to structural units. The temperatures of the exothermic peaks and the apparent activation energies for the cross-linking are different for hydroxymethylated lignins and phenol, with similar cure temperatures of the resols. Chemical oxidation using cobalt(II) and manganese(II) salts furnished oxidized lignins with improved chelating properties. These chelating agents can remove up to 14% of Mn present in pulps, decreasing the peroxide consumption in the bleaching process. The products obtained can be also used as oxidized phenols and controlled-release matrices. Oxidation of Acetosolv bagasse lignin with polyphenol oxidase furnishes lignins with chelating capacity 110% higher than that of original lignin.

Mathematical modeling of controlled-release systems of herbicides using lignins as matrices. A review

The herbicides applied in soils can be easily lost, owing to leaching, volatilization, and bio- and photodegradation. Controlled-release systems using polymeric matrices claim to solve these problems. The movement of the herbicides in the soil is also an important phenomenon to be studied in order to evaluate the loss processes. The development of mathematical models is a relevant requirement for simulation and optimization of such systems. This study reviews mathematical models as an initial step for modeling data obtained for controlled-release systems of herbicides (diuron, 2,4-dichlorophenoxyacetic acid, and ametryn) using sugarcane bagasse lignin as a polymeric matrix. The release kinetic studies were carried out using several acceptor systems including a water bath, soil, and soil-packed columns. Generally, these models take into account phenomena such as unsteady-state mass transfer by diffusion (Fick's law) and convection, consumption by several processes, and partitioning processes, resulting in partial differential equations with respect to time and space variables.