The Impact of Protein Glycosylation on the Identification of Patients with Pediatric Appendicitis.

The identification of pediatric appendicitis is challenging due to the lack of specific markers thereby several factors are included in the diagnostic process such as abdominal pain, ultrasonography and altered laboratory parameters (C reactive protein, absolute neutrophil cell number and white blood cell number). The glycosylation pattern of serum N-glycome was analyzed in this study of 38 controls and 40 patients with pediatric appendicitis. The glycans were released by enzymatic deglycosylation followed by fluorescent labeling and solid-phase extraction. The prepared samples were analyzed by hydrophilic interaction liquid chromatography with fluorescence and mass-spectrometric detection. The generated data were analyzed by multiple statistical tests involving the most important laboratory parameters as well. Significant differences associated with the examined patient groups were revealed suggesting the potential use of glycosylation analysis supporting the detection of pediatric appendicitis.

Expression of Calretinin in the Cecal Muscularis Interna: Observation and Hypothetical Relevance to Appendicitis.

BACKGROUND: The unexpected observation of calretinin immunoreactivity in smooth muscle cells in the muscularis propria of the cecum led to a more detailed examination of calretinin expression and its possible relationship to propulsive contractile activity around the vermiform appendix. METHODS: Immunohistochemistry and RNA in situ hybridization were performed to analyze calretinin expression in intestinal samples from 33 patients at ages ranging from mid-gestation fetuses to adults, as well as in some potentially relevant animal models. Dual immunolabeling was done to compare calretinin localization with markers of smooth muscle and interstitial cells of Cajal. RESULTS: Calretinin expression was observed consistently in the innermost smooth muscle layers of the muscularis interna in the human cecum, appendiceal base, and proximal ascending colon, but not elsewhere in the intestinal tract. Calretinin-positive smooth muscle cells did not co-express markers located in adjacent interstitial cells of Cajal. Muscular calretinin immunoreactivity was not detected in the ceca of mice or macaques, species which lack appendices, nor in the rabbit cecum or appendix. CONCLUSIONS: Localized expression of calretinin in cecal smooth muscle cells may reduce the likelihood of retrograde, calcium-mediated propulsive contractions from the proximal colon and suppress pro-inflammatory fecal stasis in the appendix.

Eosinophil Granule Proteins Involvement in Acute Appendicitis-An Allergic Disease?

Several pieces of evidence point to an allergic component as a trigger of acute appendicitis. As the Th2 immune response is characterized by eosinophil mobilization to the target organ and release of their cationic granule proteins, it is reasonable to investigate if the degranulation of eosinophils could be associated with the local injury. The primary aim of this study is to evaluate the participation of eosinophils granules proteins in acute appendicitis, both at local and systemic levels and the secondary aim is to evaluate the diagnostic accuracy of eosinophils granules proteins for the detection of acute appendicitis, as well as for distinguishing between complicated and uncomplicated acute appendicitis. Eosinophil-derived neurotoxin (EDN), eosinophil cationic protein (ECP) and eosinophil peroxidase (EP) are the most well-known eosinophil granule proteins. From August 2021 to April 2022, we present a prospective single-center study to evaluate the EDN, ECP, and EP concentrations simultaneously in appendicular lavage fluid (ALF) and the serum of 22 patients with acute phlegmonous appendicitis (APA), 24 with acute gangrenous appendicitis (AGA), and 14 normal controls. Concerning EDN, no differences were found between groups. ECP concentrations in ALF and serum were significantly higher in the histologically confirmed acute appendicitis compared to the control groups (p < 0.0001 and p < 0.0001, respectively). In ALF, no differences were found between ECP levels in APA: 38.85 ng/mL (IQR 26.50-51.77) and AGA 51.55 ng/mL (IQR 39.55-70.09) groups (p = 0.176). In the serum, no difference was found between ECP levels at APA: 39 ng/mL (IQR 21.30-56.90) and AGA: 51.30 ng/mL (IQR 20.25-62.59) (p = 0.100). For EP, the concentrations in ALF (p < 0.001) and serum (p < 0.001) were both higher in acute appendicitis compared to the control. In ALF, no difference was found between APA: 240.28 ng/mL (IQR 191.2-341.3) and AGA: 302.5 (IQR 227.7-535.85) (p = 0.236). In the serum, no differences were found between APA: 158.4 ng/mL (IQR 111.09-222.1) and AGA: 235.27 (IQR 192.33-262.51) (p = 0.179). Globally, the ALF concentrations were higher than serum concentrations, reflecting an intense inflammatory local reaction in AA. The optimal ECP cut-off for discriminating between acute appendicitis and the controls was >11.41 ng/mL, with a sensitivity of 93.5%, but with a specificity for identifying appendicitis of 21.4%, good discriminative power (AUC = 0.880). For EP, the optimal cut-off was >93.20 ng/mL, with a sensitivity of 87%, but with a specificity of 14.3% (AUC = 0.901), excellent discriminative power. For the diagnosis of perforated AA, the discriminative power of ECP and EP serum concentrations are weak (AUC = 0.562 and AUC = 0.664, respectively). Concerning the presence of peritonitis, the discriminative power of ECP and EP serum concentrations is acceptable, respectively: AUC = 0.724 and AUC = 0.735. Serum levels of EDN (p = 0.119), ECP (p = 0.586) and EP (p = 0.08) in complicated appendicitis were similar to uncomplicated appendicitis. Serum concentrations of ECP and EP can be added to decision-making AA diagnosis. A Th2-type immune response is present in AA. These data bring forward the role of an allergic reaction in the pathogenesis of acute appendicitis.

Differential expression of Chitinase 3-Like 1 protein in appendicitis and appendix carcinomas.

BACKGROUND: Chitinase 3-Like 1 (CHI3L1) has been used as an inflammatory biomarker for a variety of diseases, but its expression in acute appendicitis and appendix carcinomas remains unclear. METHODS: Sixty cases of patients were studied, including 46 acute appendicitis and 14 appendix carcinomas. We divided the acute appendicitis group into acute uncomplicated appendicitis (AUA), suppurative appendicitis (SA), and gangrenous appendicitis (GA). The appendix carcinoma group was divided into appendiceal neuroendocrine neoplasms (ANENs) and appendiceal mucinous neoplasms (AMN). Controls were 32 healthy donors. Blood neutrophil to lymphocyte ratio (NLR), CHI3L1, C-reactive protein (CRP), interleukin-6 (IL-6), and serum amyloid A (SAA) were measured in the patients. Meanwhile, immunohistochemistry and immunofluorescence were used to identify the expression level and location of CHI3L1 in different cell types in appendix tissues. RESULTS: Compared with the controls, CHI3L1 serum levels were up-regulated in SA, GA, and AMN groups, while no significant difference was observed in the AUA and ANEN groups. Immunofluorescence revealed that CHI3L1 expression was high in macrophages and adenocarcinoma cells of appendix tissues but not in the neuroendocrine carcinoma tissues. Moreover, levels of NLR and CRP in the SA and GA groups were considerably higher than in the control group. IL-6 and SAA in SA, GA, ANENs, and AMN groups were also increased compared with the control group. In addition, CHI3L1 displayed good performance in predicting appendicitis, with an AUC of 0.862. CONCLUSION: CHI3L1 was highly expressed in acute appendicitis and appendiceal mucinous neoplasms, which can be used as a novel biomarker predicting appendicitis.

Novel molecular biomarkers and diagnosis of acute appendicitis in children.

Reliable and efficient diagnosis of pediatric appendicitis is essential for the establishment of a clinical management plan and improvement of patient outcomes. Current strategies used to diagnose a child presenting with a suspected appendicitis include laboratory studies, clinical scores and diagnostic imaging. Although these modalities work in conjunction with each other, one optimal diagnostic strategy has yet to be agreed upon. The recent introduction of precision medicine techniques such as genomics, transcriptomics, proteomics and metabolomics has increased both the diagnostic sensitivity and specificity of appendicitis. Using these novel strategies, the integration of precision medicine into clinical practice via point-of-care technologies is a plausible future. These technologies would assist in the screening, diagnosis and prognosis of pediatric appendicitis.

Associations of hair cortisol concentrations with paediatric appendicitis.

The pathogenesis of paediatric appendicitis is still an enigma. In recent years, it has become more evident that our inherent immunological responses affect the trajectory of the disease course. Long-term stress has an impact on our immune system; however, it is practically and ethically challenging to prospectively track blood measurements of cortisol-levels in asymptomatic children should an acute appendicitis episode develop. The aim of this case-control study was therefore to evaluate the effect of increased stress measured as historical imprints in hair (hair cortisol concentrations [HCC]), on the risk of developing appendicitis and complicated appendicitis. 51 children (aged < 15 years) with appendicitis (34 with complicated appendicitis), were compared to 86 healthy controls. HCC reflecting the activity of the HPA-axis 0-3 and 4-6 months prior to sampling was evaluated and compared between groups as well as between the two measurements of each study subject. In the univariate analysis with both cases and controls, an increase in HCC between the measurement timepoints was associated with a substantial increase in risk of appendicitis (OR 7.52 [95% CI 2.49-22.67], p = 0.001). This increased risk remained in the multivariate analysis after adjustment for age, sex and season (aOR OR 10.76 [95%CI 2.50-46.28], p = 0.001). When comparing the cases of uncomplicated and complicated appendicitis through a multivariate analysis, adjusted for age and sex, the children with an increased HCC prior to appendicitis had a substantial and statistically significant increase in risk of complicated appendicitis (aOR 7.86 [95% CI 1.20-51.63], p = 0.03). Biological stress, measured as an increase in HCC, seems to be associated with an increased risk of paediatric appendicitis and a more complicated disease course.

Markers of neutrophil activation and extracellular traps formation are predictive of appendicitis in mice and humans: a pilot study.

Appendicitis is one of the most frequent emergencies in pediatric surgery, yet current biomarkers for diagnosis are unspecific and have low predictive values. As neutrophils and extracellular traps (ETs) are an essential component of the immune defense against bacterial infections, and appendicitis is considered an inflammation reaction of the appendix, we hypothesized that neutrophil activation and NET formation play an essential role in appendicitis development and maintenance. Therefore, this pilot study aimed to establish a murine model of appendicitis and to evaluate ETs markers to diagnose appendicitis in mice and humans. The study used 20 (12 appendicitis- and 8 controls) 6-week old mice which underwent advanced appendicitis induction using a modified caecal ligation puncture procedure. During the study, cell-free DNA, neutrophil elastase (NE), myeloperoxidase (MPO), and citrullinated Histone H3 (H3cit) were assessed. Additionally, samples of 5 children with histologically confirmed appendicitis and 5 matched controls with catarrhal appendicitis, were examined for the same biomarkers. Moreover, NE, MPO, and H3cit were assessed histologically via immunofluorescence in mice and humans. All mice in the appendicitis group developed an advanced form of appendicitis with focal peritonitis. In mice and humans with appendicitis, markers of neutrophil activation and ETs formation (especially cfDNA, NE and H3cit) were significantly elevated in blood and tissue compared to controls. Ultimately, biomarkers correlated extremely well with tissue expression and thus disease severity. It appears that neutrophil activation and possibly NETs contribute to appendicitis development and biomarkers of neutrophil activation and ET formation reflect disease severity and thus could be used as biomarkers for appendicitis. However, large prospective clinical studies are needed to confirm our findings.

Blockage of C-C Chemokine Ligand 2 Alleviated the Appendicitis-Induced Injury in Rabbit Model.

C-C chemokine ligand 2 (CCL2), a low-molecular-weight cytokine, is upregulated in inflammation-related diseases. However, the underlying function of CCL2 remains unknown in human appendicitis. The present study aimed to examine the role of CCL2 in appendicitis. An enzyme-linked immunosorbent assay was performed to examine the secretion of CCL2 in the peripheral blood of patients with simple and complex appendicitis, respectively. A flow cytometry assay was used to quantify the level of the CCL2 receptor, CCR2. Moreover, we constructed an appendicitis model in rabbits. Quantitative real time-polymerase chain reaction and Western blot were used to determine CCL2 and CCR2 levels in the appendicitis model. CCL2 antibodies were used to silence the endogenous activity of CCL2 in vivo. Magnetic resonance imaging and a histopathology assay were used to examine the appendicitis-induced injury in rabbits. Our results suggested that CCL2 and its main receptor CCR2 were upregulated in patients with appendicitis, particularly those with complex appendicitis (gangrenous and perforated appendicitis). Moreover, CCL2 silencing alleviated the appendicitis-induced injury in rabbits. Our findings not only illustrate the potential value of CCL2 as a biomarker in appendicitis diagnosing but also provide novel insight into appendicitis treatment.

18F-Fluciclovine Uptake in Acute Appendicitis.

An 85-year-old man with biochemical recurrence of prostate cancer after prostatectomy was imaged with F-fluciclovine PET/CT. Images incidentally revealed F-fluciclovine uptake in a dilated appendix with associated fat stranding, suggestive of acute appendicitis. The patient was then questioned about abdominal symptoms, and he reported severe right lower quadrant pain. He then underwent laparoscopic appendectomy with pathology confirming acute appendicitis.

Evaluation of some cellular biomarker proteins, oxidative stress and clinical indices as results of laparoscopic appendectomy for perforated appendicitis in children.

Laparoscopic appendectomy for perforated appendicitis in children has the advantages of quick recovery, little influence of inflammatory and oxidative stress and low infection rate. Altogether 115 children with perforated appendicitis treated in our hospital from June 2018 to August 2019 were selected and divided into two groups according to different treatment methods. Laparoscopic appendectomy was used as the research group (RG) (67 cases) and open appendectomy (48 cases) as the control group (CG). The clinical indexes (operation time, intraoperative blood loss, ambulation time, incision length, postoperative exhaust time and length of stay) of the two groups were observed. The levels of C- reactive protein (CRP), procalcitonin (PCT), interleukin -6 (IL-6) and tumor necrosis factor-α (TNF-α) before and after treatment were detected by enzyme-linked immunosorbent assay (ELISA). The levels of oxidative stress factors (superoxide dismutase (SOD), malondialdehyde (MDA)) and the incidence of postoperative incision infection were observed in the two groups. A visual analogue scale (VAS) score was used to evaluate the postoperative pain in children. Logistic regression analysis was used to analyze the risk factors of postoperative incision infection in children. The improvement degree of clinical indicators in RG was significantly better than that in CG. The expression levels of CRP, PCT, IL-6 and TNF-α in RG were significantly lower than those in CG. The expression levels of SOD and MDA in RG were significantly better than those in CG. The postoperative incision infection rate in RG was significantly lower than that in CG. The postoperative VAS score in RG was significantly lower than that in CG. Logistic regression analysis results showed that the risk of incision infection was increased in children with operation time over 1h, incision length >3cm, high CRP, high PCT, high IL-6, high TNF-α, high SOD and low MDA. Laparoscopic appendectomy for perforated appendicitis in children can effectively reduce intraoperative hemorrhage, postoperative pain, and the damage to the body of children, and can also reduce oxidative stress and inflammatory reaction in children.

Salivary biomarker for acute appendicitis in children: a pilot study.

PURPOSE: Assays of salivary biomarkers for diagnosis are gaining popularity in pediatric diseases due to their non-invasive nature. Our pilot project aims to evaluate the utility of salivary leucine-rich-alpha-2-glycoprotein (LRG) in the diagnosis of pediatric acute appendicitis (AA). METHODS: We prospectively recruited 34 patients, aged between 4 and 16 years, admitted with acute abdominal pain suspicious of appendicitis. The patients' demography, clinical characteristics, laboratory investigations, imaging examination results, operative findings, and discharge diagnoses were recorded. We compared the diagnostic performance of the patients' total white counts, neutrophil percentages, C-reactive protein, and saliva LRG levels. Saliva samples were obtained using the SalivaBio Children's Swab and LRG levels were quantified using a commercially available LRG enzyme-linked immunosorbent assay (ELISA) kit. IRB approval was obtained. RESULTS: Seventeen patients had a confirmed diagnosis of appendicitis on histology. Another 17 were confirmed not to have appendicitis after a minimum of 24 h of hospitalization, with further verification via telephone interview 2 weeks later. The median levels of saliva LRG were elevated in patients with AA as compared to those without (P = 0.008). At a cutoff of LRG 0.33 ng/µg, we obtained a diagnostic specificity of 100% and sensitivity of 35.3%. CONCLUSION: Our proof-of-concept study demonstrated the diagnostic potential of saliva LRG for appendicitis in children. The distinct advantage of saliva LRG assays is that the procedure is simple, pain-free, and requires no specialized skill. Further study with a larger cohort is needed to verify our results.

Determining acute complicated and uncomplicated appendicitis using serum and urine biomarkers: interleukin-6 and neutrophil gelatinase-associated lipocalin.

PURPOSE: The study aim is to determine whether serum and urine interleukin-6 (IL-6) and neutrophil gelatinase-associated lipocalin (NGAL) can be included in the early diagnostic algorithm for pediatric appendicitis. METHODS: Prospective single-center cohort study included 92 children divided into control, acute complicated appendicitis (AcA) and acute uncomplicated appendicitis (AnA) groups. Serum and urine samples were assayed for IL-6 and NGAL preoperatively, and on the second and fifth postoperative days. Intraoperative and bacteriological findings divided the appendicitis patients. RESULTS: Average serum biomarker levels were higher in appendicitis patients versus the control, and the following values were produced via receiver operating characteristic (ROC) analysis. NGAL and IL-6 cutoff values were 113.95 ng/ml and 24.64 pg/ml, respectively, NGAL had 68.3% sensitivity and 65.5% specificity, while IL-6 had 72.6% and 86.2%. Comparing AcA and AnA, IL-6 was the only biomarker of significance yielding 77.4% sensitivity and 58.1% specificity with a 26.43 pg/ml cutoff value. Urine biomarkers were non-specific in differentiation appendicitis severity and ultimately, between infectious and non-infectious disease. CONCLUSION: Although NGAL provided measurable useful diagnostic information in evaluating children for appendicitis, its values were not sufficient for appendicitis severity. Serum IL-6 remains a strong biomarker for suspected acute appendicitis and has promising results predicting its severity.

AppendiXNet: Deep Learning for Diagnosis of Appendicitis from A Small Dataset of CT Exams Using Video Pretraining.

The development of deep learning algorithms for complex tasks in digital medicine has relied on the availability of large labeled training datasets, usually containing hundreds of thousands of examples. The purpose of this study was to develop a 3D deep learning model, AppendiXNet, to detect appendicitis, one of the most common life-threatening abdominal emergencies, using a small training dataset of less than 500 training CT exams. We explored whether pretraining the model on a large collection of natural videos would improve the performance of the model over training the model from scratch. AppendiXNet was pretrained on a large collection of YouTube videos called Kinetics, consisting of approximately 500,000 video clips and annotated for one of 600 human action classes, and then fine-tuned on a small dataset of 438 CT scans annotated for appendicitis. We found that pretraining the 3D model on natural videos significantly improved the performance of the model from an AUC of 0.724 (95% CI 0.625, 0.823) to 0.810 (95% CI 0.725, 0.895). The application of deep learning to detect abnormalities on CT examinations using video pretraining could generalize effectively to other challenging cross-sectional medical imaging tasks when training data is limited.

A Th2 Cytokine Profile in Appendicular Lavage Fluid Suggests Allergy as a Possible Etiology for Acute Appendicitis.

Acute appendicitis is the most frequent surgical abdominal emergency, but its etiology remains poorly understood. Histological examination of the appendix, following its removal due to acute appendicitis, consistently shows features in common with bronchial asthma, suggesting an allergic reaction as a candidate etiologic factor. Here, we propose the concept of appendicular lavage and use it to study the levels of the Th2 cytokines IL-4, IL-5, and IL-9 in patients with a clinical diagnosis of acute appendicitis. The study group included 20 patients with a histological diagnosis of phlegmonous appendicitis, 13 patients with gangrenous appendicitis, and a control group of 8 patients with a clinical diagnosis of appendicitis but with normal histology. Cytokine levels were higher in acute appendicitis. The difference was more pronounced when comparing phlegmonous appendicitis with nonpathological appendicitis (p = 0.01) for IL-4 (48.3 vs. 21.3 pg/mL), IL-5 (29.2 vs. 8.0 pg/mL), and IL-9 (34.1 vs. 16.6 pg/mL). This Th2 cytokine profile is compatible with the hypothesis of allergy as an etiologic factor for acute appendicitis and may have important implications for the diagnosis, prevention, and treatment of this condition.

Possible cytokine biomarkers in pediatric acute appendicitis.

BACKGROUND: Diagnosis of acute appendicitis (AA) and decisions about its treatment remain among the most common dilemmas of pediatric surgical teams. Monitoring of immune response may be of importance for this purpose. Our aim was to measure and analyze serum and peritoneal fluid cytokines, in children who had undergone surgery for suspected AA. METHODS: Prospective investigation of serum and peritoneal fluid cytokine values was performed in 127 consecutive patients. According to the pathohistological findings, patients were divided into three groups: normal/early, uncomplicated and complicated AA. Determination of cytokine concentrations for 20 different cytokines was done using a commercial flow cytometry kit: Human Inflammation 20 plex BMS 819. RESULTS: Statistically significant differences in serum cytokine values between pathohistological groups were found for IP-10, MIP-1α and IL-10. Preoperative cut-off values of IP-10, MIP-1α and IL-10 between groups were obtained using ROC curve analysis. Positive correlations between serum and peritoneal concentrations were recorded for most of the analyzed cytokines. CONCLUSION: IP-10, MIP-1α and IL-10 showed potential in assessment of AA in children. Confirmatory studies with a larger number of patients are required to prove reliability of these biomarkers.

Association of chronic and acute inflammation of the mucosa-associated lymphoid tissue with psychiatric disorders and suicidal behavior.

Immune dysregulation due to chronic inflammation is a hypothesized risk factor underlying psychiatric disorders and suicidal behavior. Whether tonsillectomy and acute appendicitis used, respectively, as proxies for chronic and acute inflammation within the mucosa-associated lymphoid tissue (MALT) are associated with psychiatric disorders and suicidal behavior is currently unknown. A birth cohort study was conducted including 3,052,875 individuals born in Sweden between 1973 and 2003. We identified 210,686 individuals ever exposed to tonsillectomy and 86,928 individuals ever exposed to acute appendicitis, as well as 317,214 clusters of siblings discordant for tonsillectomy, and 160,079 sibling clusters discordant for acute appendicitis. Outcomes were an aggregate risk of 'any psychiatric disorder', 'any suicidal behavior', 12 individual psychiatric disorders, suicide attempts and deaths by suicide. Tonsillectomy was associated with increased odds of 'any psychiatric disorder' (adjusted odds ratio [aOR] = 1.39; 95% confidence interval (CI) = 1.38-1.41) and 'any suicidal behavior' (aOR = 1.41; 95% CI = 1.37-1.44), and most individual disorders. Acute appendicitis also increased the odds of 'any psychiatric disorder' and 'any suicidal behavior' (aOR = 1.23; 95% CI = 1.20-1.25, and aOR = 1.32; 95% CI = 1.28-1.37, respectively). Exposure to both tonsillectomy and appendicitis was associated with the highest odds of 'any psychiatric disorder' (aOR = 1.70; 95% CI = 1.59-1.82) and 'any suicidal behavior' (aOR = 1.90; 95% CI = 1.70-2.12). In sibling comparisons, the associations were attenuated but remained significant. We conclude that inflammation within the MALT, particularly when chronic, is robustly associated with a broad range of psychiatric disorders and suicidal behavior.

Cytokines and Chemokines in Pediatric Appendicitis: A Multiplex Analysis of Inflammatory Protein Mediators.

OBJECTIVES: We aimed to demonstrate the potential of precision medicine to describe the inflammatory landscape present in children with suspected appendicitis. Our primary objective was to determine levels of seven inflammatory protein mediators previously associated with intra-abdominal inflammation (C-reactive protein-CRP, procalcitonin-PCT, interleukin-6 (IL), IL-8, IL-10, monocyte chemoattractant protein-1-MCP-1, and serum amyloid A-SAA) in a cohort of children with suspected appendicitis. Subsequently, using a multiplex proteomics approach, we examined an expansive array of novel candidate cytokine and chemokines within this population. METHODS: We performed a secondary analysis of targeted proteomics data from Alberta Sepsis Network studies. Plasma mediator levels, analyzed by Luminex multiplex assays, were evaluated in children aged 5-17 years with nonappendicitis abdominal pain (NAAP), acute appendicitis (AA), and nonappendicitis sepsis (NAS). We used multivariate regression analysis to evaluate the seven target proteins, followed by decision tree and heat mapping analyses for all proteins evaluated. RESULTS: 185 children were included: 83 with NAAP, 79 AA, and 23 NAS. Plasma levels of IL-6, CRP, MCP-1, PCT, and SAA were significantly different in children with AA compared to those with NAAP (p < 0.001). Expansive proteomic analysis demonstrated 6 patterns in inflammatory mediator profiles based on severity of illness. A decision tree incorporating the proteins CRP, ferritin, SAA, regulated on activation normal T-cell expressed and secreted (RANTES), monokine induced by gamma interferon (MIG), and PCT demonstrated excellent specificity (0.920) and negative predictive value (0.882) for children with appendicitis. CONCLUSIONS: Multiplex proteomic analyses described the inflammatory landscape of children presenting to the ED with suspected appendicitis. We have demonstrated the feasibility of this approach to identify potential novel candidate cytokines/chemokine patterns associated with a specific illness (appendicitis) amongst those with a broad ED presentation (abdominal pain). This approach can be modelled for future research initiatives in pediatric emergency medicine.

Volume kinetics of Ringer's lactate solution in acute inflammatory disease.

BACKGROUND: Little is known about the turnover of crystalloid fluids infused in patients with acute systemic inflammation. We hypothesised that systemic inflammation would be associated with altered distribution and elimination of Ringer's lactate solution (volume kinetics). METHODS: Ringer's lactate solution (15 ml kg-1) was infused intravenously over 35 min in patients undergoing cholecystectomy (n=20) or appendectomy (n=20) starting before induction of general anaesthesia. Blood samples and urine were collected over the following 2 h. Plasma concentrations of inflammatory (tumour necrosis factor-α, interleukin-10, and C-reactive protein) and endothelial damage (syndecan-1) biomarkers were quantified by enzyme-linked immunosorbent assay. The volume kinetics was studied using mixed-effect modelling. RESULTS: Ongoing surgery (duration: 30-45 min) increased the rate constant for fluid transfer from the plasma to the extravascular space (k12; from 32 to 57×10-3 min-1; P<0.001), and decreased the elimination rate constant (k10; from 5.3 to 0.6×10-3 min-1; P<0.001). A lower mean arterial pressure was associated with reduced elimination, independent of conscious/anaesthetised state. The redistribution of fluid back to the plasma occurred more slowly in the group with appendicitis (P<0.02), in whom higher plasma concentrations of C-reactive protein were measured [median: 38.1 (range 1.8-143.6) vs 1.3 (0.1-159.0) µg ml-1; P<0.001]. However, no biomarkers for inflammation or endothelial damage were significantly associated covariates in the kinetic model. CONCLUSIONS: No association was found between the volume kinetics of Ringer's lactate solution and the degree of inflammation as indicated by established biomarkers in patients with cholecystitis or appendicitis. However, the rate of elimination was greatly retarded by general anaesthesia in both groups. CLINICAL TRIAL REGISTRATION: ChiCTR-IOR-15006063.