Bromopyrylium Derivatization Facilitates Identification by Mass Spectrometry Imaging of Monoamine Neurotransmitters and Small Molecule Neuroactive Compounds

Mass spectrometry imaging using matrix-assisted laser desorption/ionization and desorption electrospray ionization has recently been employed to investigate the distribution of neurotransmitters, including biogenic amines and amino acids, directly in brain tissue sections. Ionization is facilitated by charge-tagging through pyrylium derivatization of primary amine containing neurotransmitters directly in tissue sections, significantly improving the limit of detection. Since the derivatization adds carbon and hydrogen to the target compounds, the resulting isotopic patterns of the products are not distinctive from those of the nonderivatized species. Here, we describe an approach for chemically modifying the reactive pyrylium ion to introduce the distinct isotopic signature of bromine in mass spectra of chemically derivatized substances in tissue sections. The method enables monoamine compounds to be distinguished directly in tissue sections, facilitating their identification.

Cross-validated Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging Quantitation Protocol for a Pharmaceutical Drug and Its Drug-Target Effects in the Brain Using Time-of-Flight and Fourier Transform Ion Cyclotron Resonance Analyzers

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is an established tool in drug development, which enables visualization of drugs and drug metabolites at spatial localizations in tissue sections from different organs. However, robust and accurate quantitation by MALDI-MSI still remains a challenge. We present a quantitative MALDI-MSI method using two instruments with different types of mass analyzers, i.e., time-of-flight (TOF) and Fourier transform ion cyclotron resonance (FTICR) MS, for mapping levels of the in vivo-administered drug citalopram, a selective serotonin reuptake inhibitor, in mouse brain tissue sections. Six different methods for applying calibration standards and an internal standard were evaluated. The optimized method was validated according to authorities’ guidelines and requirements, including selectivity, accuracy, precision, recovery, calibration curve, sensitivity, reproducibility, and stability parameters. We showed that applying a dilution series of calibration standards followed by a homogeneously applied, stable, isotopically labeled standard for normalization and a matrix on top of the tissue section yielded similar results to those from the reference method using liquid chromatography–tandem mass spectrometry (LC–MS/MS). The validation results were within specified limits and the brain concentrations for TOF MS (51.1 ± 4.4 pmol/mg) and FTICR MS (56.9 ± 6.0 pmol/mg) did not significantly differ from those of the cross-validated LC–MS/MS method (55.0 ± 4.9 pmol/mg). The effect of in vivo citalopram administration on the serotonin neurotransmitter system was studied in the hippocampus, a brain region that is the principal target of the serotonergic afferents along with the limbic system, and it was shown that serotonin was significantly increased (2-fold), but its metabolite 5-hydroxyindoleacetic acid was not. This study makes a substantial step toward establishing MALDI-MSI as a fully quantitative validated method.

Abstract 6124: Translation of zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in urinary bladder cancer patients

Precision medicine in oncology aims to identify the most effective treatment for any given patient based on individualized analyses of patient material. Currently, precision medicine relies on sequencing of DNA or RNA to identify patient tumor-specific mutational profiles that may be coupled to drug response. These techniques, however, fail to reveal actionable mutations in approximately 85% of the cancer patients, and have not been established at all for many commonly used drugs including cisplatin-based treatments used in urinary bladder cancer. While mouse-PDX models can determine drug response rates with high accuracy in most patients and for most drugs, such techniques are too slow and expensive to be relevant for first line treatment planning. Urinary bladder cancer patients are often treated with cisplatin-containing combination therapy, with the hope of down-staging tumors before surgery. 60%, however, do not respond or even progress on this treatment, and these patients would benefit from immediate surgery upon diagnosis. To help identify non-responding patients, we show here that patient-derived tumor xenograft models can be established in zebrafish larvae (ZTX models) and that the resulting tumors exhibit differential responses to the two main cisplatin-containing treatments GC and MVAC.

Preliminary results from the first 19 patients are presented. Two tumor biopsies were destroyed during transport and two did not allow isolation of sufficient viable cells for implantation. From the remaining 15 samples an average of 2,6 million cells with average viability of 53% were isolated and used to implant at least 60 2-days old larvae. All 15 samples implanted in the larvae and survived and/or grew exhibiting varying degrees of metastatic dissemination (average between 2 and 13 metastasized cells per embryo and model) within only three days from implantation. Four ZTX models exhibited different responses to GC and MVAC demonstrating that these treatments are not equally effective in all patients. Non-response in ZTX models was associated with tumors having re-appeared in the bladder upon radical cystectomy in all patients undergoing surgery prior to Dec. 5th 2019 (n=3). GC inhibited metastasis in all models (average 69% inhibition), whereas MVAC inhibited metastasis in 40% of the models (average 36% inhibition).

In conclusion: The ZTX urinary bladder cancer platform presented here overcome limitations associated with long assay time and high cost of other functional models within precision medicine as well as the low hit-rate of actionable mutations associated with genomic techniques. ZTX models will therefore likely become a powerful method for functional precision medicine within oncology, in the near future.

Citation Format: Zaheer Ali, Anna Nilsson, Malin Vildevall, Larissa Rizzo, Ylva Huge, Amir Sherif, Anna Fahlgren, Lasse DE Jensen. Translation of zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in urinary bladder cancer patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6124.

Abstract 6126: Zebrafish patient tumor-derived xenograft models used for pre-clinical evaluation of CAN04 for lung and pancreatic cancer

Lung cancer is one of the most deadly diseases accounting for 24% of all cancer deaths worldwide. One reason for this high mortality is the high interindividual heterogeneity but generally poor efficacy of current treatments, leading to an urgent need for new and more effective drugs. Understanding the individual variability in the efficacy of new treatment candidates, delineating whether they should be combined with existing chemotherapeutics and to what extent they affect metastatic dissemination of the tumor cells are key preclinical indicators needed to increase the chance of success in clinical trials. Developing such data, however, requires animal models that recapitulate individual differences of different lung cancer patients, include insights into metastatic activity and allow analysis of a large amounts of treatment combinations for each patient model. As such, an in vivo screening system which has higher throughput than mouse models and at the same time allows analysis of metastatic activity would be very valuable in mimicking human disease.

Here we conducted zebrafish patient tumor derived xenograft (PDX)-studies based on cisplatin sensitive and -resistant lung cancer PDX material, to test the efficacy of a a novel antibody, CAN04, under development for this indication. CAN04 targets Interleukin-1 Accessory Protein (IL1RAP) and has shown synergistic effects with cisplatin in murine models of cancer. CAN04 is currently in phase II development in combination with chemotherapy in lung cancer and pancreatic cancer. CAN04 was given either alone or with cisplatin at three different concentrations, and the effects on primary tumor growth and metastasis three days after tumor implantation was evaluated. We show that CAN04 was able to synergize with cisplatin in causing almost complete (85%-98%) tumor regression even of cisplatin-resistant tumors, compared to non-treated controls. The effects were concentration- and model-dependent. Interestingly, in the cisplatin-resistant model, the antibody and cisplatin co-treatment led to robust inhibition of metastatic dissemination, which was not seen in either group alone. This substantiates the beneficial therapeutic efficacy of combining CAN04 to cisplatin treatment in lung cancer.

In conclusion, zebrafish-PDX (ZTX) models are powerful tools for evaluating individual differences in drug sensitivity on both primary tumor growth and metastasis and are suitable for screening various drug concentrations and/or combinations in multiple models with results being generated within one or a few weeks. We further conclude that CAN04 is inducing cisplatin sensitivity and synergize with cisplatin to inhibit metastasis, at least in some cisplatin resistant lung cancers.

Citation Format: Zaheer Ali, Anna Nilsson, Malin Vildevall, Julia Schueler, David Liberg, Anna Fahlgren, Lasse DE Jensen. Zebrafish patient tumor-derived xenograft models used for pre-clinical evaluation of CAN04 for lung and pancreatic cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6126.

The Feasibility of Host Transcriptome Profiling as a Diagnostic Tool for Microbial Etiology in Childhood Cancer Patients with Febrile Neutropenia

Infection is a common and serious complication of cancer treatment in children that often presents as febrile neutropenia (FN). Gene-expression profiling techniques can reveal transcriptional signatures that discriminate between viral, bacterial and asymptomatic infections in otherwise healthy children. Here, we examined whether gene-expression profiling was feasible in children with FN who were undergoing cancer treatment. The blood transcriptome of the children (n = 63) was investigated at time of FN diagnosed as viral, bacterial, co-infection or unknown etiology, respectively, and compared to control samples derived from 12 of the patients following the FN episode. RNA sequencing was successful in 43 (68%) of the FN episodes. Only two genes were significantly differentially expressed in the bacterial versus the control group. Significantly up-regulated genes in patients with the other three etiologies versus the control group were enriched with cellular processes related to proliferation and cellular stress response, with no clear enrichment with innate responses to pathogens. Among the significantly down-regulated genes, a few clustered into pathways connected to responses to infection. In the present study of children during cancer treatment, the blood transcriptome was not suitable for determining the etiology of FN because of too few circulating immune cells for reliable gene expression analysis.

Deficits in the IgG+ memory B-cell recovery after anthracycline treatment is confined to the spleen of rhesus macaques

Objectives

Loss of vaccine‐induced antibodies (Abs) after chemotherapy against paediatric acute lymphoblastic leukaemia (ALL) is common and often necessitates re‐immunisation after cessation of treatment. Even so, some ALL survivors fail to mount or to maintain protective Abs. Germinal centres (GCs) are clusters of proliferating B cells in follicles of secondary lymphoid tissues (SLTs) formed during adaptive immune responses and the origins of long‐lived memory B and plasma cells that are the source of Abs. Furthermore, productive GC reactions depend on T follicular helper (T_FH) cells. To understand why chemotherapy induces deficits in Ab responses, we examined how SLTs were affected by chemotherapy.

Methods

Rhesus macaques were infused with either three cycles of the anthracycline doxorubicin or saline, followed by immunisation with a de novo and booster antigen. Spleen and lymph nodes were removed, and memory B, bulk T and T_FH cells were examined.

Results

Despite adequate GC morphology, a diminished memory and IgG⁺ B‐cell population along with diminished total and booster vaccine‐specific IgG‐producing memory B cells were noted in the spleens of macaques with past doxorubicin exposure compared to the saline‐treated controls (P < 0.05). Intact bulk T and T_FH cells were found in the SLTs of treated macaques, which displayed higher CD40L upregulation capacity by their splenic CXCR5⁺ helper T cells (P < 0.01). In contrast to the spleen, the immune cell populations studied were comparable between the lymph nodes of both saline‐ and doxorubicin‐treated macaques.

Conclusion

Our findings suggest that the splenic memory B‐cell subset, compared to its lymph node counterpart, is more severely altered by anthracycline treatment.

Vulnerability to helpless behavior is regulated by the circadian clock component CRYPTOCHROME in the mouse nucleus accumbens

The nucleus accumbens (NAc), a central component of the midbrain dopamine reward circuit, exhibits disturbed circadian rhythms in the postmortem brains of depressed patients. We hypothesized that normal mood regulation requires proper circadian timing in the NAc, and that mood disorders are associated with dysfunctions of the NAc cellular circadian clock. In mice exhibiting stress-induced depression-like behavior (helplessness), we found altered circadian clock function and high nighttime expression of the core circadian clock component CRYPTOCHROME (CRY) in the NAc. In the NAc of helpless mice, we found that higher expression of CRY is associated with decreased activation of dopamine 1 receptor-expressing medium spiny neurons (D1R-MSNs). Furthermore, D1R-MSN-specific CRY-knockdown in the NAc reduced susceptibility to stress-induced helplessness and increased NAc neuronal activation at night. Finally, we show that CRY inhibits D1R-induced G protein activation, likely by interacting with the Gs protein. Altered circadian rhythms and CRY expression were also observed in human fibroblasts from major depressive disorder patients. Our data reveal a causal role for CRY in regulating the midbrain dopamine reward system, and provide a mechanistic link between the NAc circadian clock and vulnerability to depression.

Peripheral facial nerve palsy in children in a Borrelia high-endemic area, a retrospective follow-up study

AIM

To identify the incidence, aetiology and prognosis of acute peripheral facial nerve palsy (FNP) in children in the Borrelia high-endemic region of Stockholm.

METHODS

The present study identified children from 0 to 18 years of age who visited a paediatric emergency department for acute peripheral FNP during a 1-year period from 2014 to 2015. Data were collected retrospectively. The Sunnybrook and House-Brackmann facial grading systems were used to measure clinical outcome.

RESULTS

A total of 77 children were identified with FNP, an estimated incidence of 30 per 100 000 children/year. Forty-five children (58%) were diagnosed with neuroborreliosis, 28 (36%) with idiopathic FNP and four (6%) with other rarer causes. Neuroborreliosis was common from June to November and mainly seen in children below 10 years of age. Six patients (8%) had remaining symptoms at least 3 months after onset; three had idiopathic facial palsy (IFP) and were all older than 10 years, one had neuroborreliosis and two had other causes.

CONCLUSION

Neuroborreliosis and IFP were the major causes of FNP during the study period. Neuroborreliosis-associated facial palsy had a seasonal variation and dominated in younger ages.

Fatal encephalitis associated with coronavirus OC43 in an immunocompromised child

A child with pre-B acute lymphoblastic leukaemia (ALL) developed fatal encephalitis associated with human coronavirus OC43 (HCoV-OC43). During chemotherapy the child had a persistent HCoV-OC43 respiratory infection and later developed progressive encephalitis. Cerebrospinal fluid was negative for pathogens including HCoV-OC43, but a brain biopsy was HCoV-OC43-positive by metagenomic next-generation sequencing.

The Role of TPMT, ITPA, and NUDT15 Variants during Mercaptopurine Treatment of Swedish Pediatric Patients with Acute Lymphoblastic Leukemia

OBJECTIVE

To evaluate the roles of thiopurine methyltransferase (TPMT), inosine triphosphatase (ITPA), and Nudix hydrolase 15 (NUDT15) in 6-mercaptopurine (6-MP) sensitivity during treatment of pediatric patients with acute lymphoblastic leukemia (ALL).

STUDY DESIGN

The study included 102 pediatric patients with ALL subject to the Nordic society Of Paediatric Haematology and Oncology (NOPHO) ALL-2000 and ALL-2008 protocols. Episodes of neutropenia and febrile neutropenia, TPMT sequence variants, as well as 6-MP end doses, were collected retrospectively from medical records. TPMT, ITPA, and NUDT15 sequence variants were analyzed using pyrosequencing.

RESULTS

TPMT variants were associated with a reduced risk of neutropenia and febrile neutropenia during the maintenance II period (P = .019 and P < .0001, respectively). In addition, a NUDT15 variant was associated with a lower end dose of 6-MP (P = .0097), but not with neutropenia and febrile neutropenia. ITPA variants were not associated with an increased risk of neutropenia, febrile neutropenia, nor lower end dose of 6-MP. However, when analyzing the entire treatment period, ITPA variants were associated with a decreased risk of febrile neutropenia.

CONCLUSIONS

White blood cell count-based dose adjustments are regularly performed for known TPMT- deficient patients and results in a reduced risk of neutropenia and febrile neutropenia. Also in NUDT15-deficient patients dose adjustments are performed as indicated by low end dose of 6-MP. ITPA-deficient patients had a decreased risk of febrile neutropenia when analyzing the entire treatment period. Our data suggest that NUDT15 plays an important role in 6-MP treatment and the results should be confirmed in larger cohorts. Future studies should also follow up whether white blood cell count-based dose adjustments affect the risk of relapse.

[Hypocomplementemic urticarial vasculitis syndrome: a rare but not always benign condition]

Although more than 45 years have passed since hypocomplementemic urticarial vasculitis (HUVS) was first described by McDuffie and colleagues at the Mayo clinic, data on epidemiology, disease outcomes, prognosis and clinical features are scarce. Recently, we published the first epidemiological study of HUVS including data on incidence, prevalence, disease outcomes, prognosis and clinical features using data from two separate Swedish regions during a period of 16 years. The estimation of incidence and prevalence rates indicates that HUVS is rare but not always benign. Renal and lung manifestations were severe in some cases, highlighting the need for careful screening and monitoring of this potentially serious condition. It is reasonable to suspect HUVS in patients with unexplained systemic inflammation combined with >6 months of urticaria. Special attention should be paid to patients with recent-onset dyspnea and proteinuria.

Urinary PGE2 metabolite levels in hospitalised infants with infections compared to age-matched controls

AIM

To determine the urinary tetranor-prostaglandin E₂ metabolite in healthy infants and in hospitalised infants with upper and lower respiratory tract as well as gastrointestinal infections.

METHODS

A prospective cross-sectional study to determine baseline concentrations of urinary tetranor-prostaglandin E₂ metabolite was conducted in 81 healthy infants aged one week to one year and in 142 hospitalised infants with infections. Prostaglandin metabolite levels were measured by liquid chromatography tandem mass spectrometry.

RESULTS

In healthy infants, urinary prostaglandin E₂ metabolite levels decreased with age and did not differ between girls and boys. Infections of the lower respiratory (n = 78) and gastrointestinal tract (n = 12) correlated with increased levels of the prostaglandin E₂ metabolite. In contrast, infants hospitalised with upper respiratory tract infections (n = 23) exhibited similar levels as healthy, age-matched controls. Lower prostaglandin E₂ levels were found after treatment with acetaminophen in hospitalised children. Prostaglandin E₂ metabolite levels did not correlate with length of hospitalisation or need for respiratory support.

CONCLUSION

This study first provides normal levels of urinary prostaglandin E₂ metabolite in infants and secondly demonstrates elevated levels in hospitalised children with lower respiratory tract and gastrointestinal infections.

Comprehensive mapping of neurotransmitter networks by MALDI-MS imaging

We present a mass spectrometry imaging (MSI) approach for the comprehensive mapping of neurotransmitter networks in specific brain regions. Our fluoromethylpyridinium-based reactive matrices facilitate the covalent charge-tagging of molecules containing phenolic hydroxyl and/or primary or secondary amine groups, including dopaminergic and serotonergic neurotransmitters and their associated metabolites. These matrices improved the matrix-assisted laser desorption/ionization (MALDI)-MSI detection limit toward low-abundance neurotransmitters and facilitated the simultaneous imaging of neurotransmitters in fine structures of the brain at a lateral resolution of 10 µm. We demonstrate strategies for the identification of unknown molecular species using the innate chemoselectivity of the reactive matrices and the unique isotopic pattern of a brominated reactive matrix. We illustrate the capabilities of the developed method on Parkinsonian brain samples from human post-mortem tissue and animal models. The direct imaging of neurotransmitter systems provides a method for exploring how various neurological diseases affect specific brain regions through neurotransmitter modulation.

Differences in virulence gene expression between human blood and stool Campylobacter coli clade 1 ST828CC isolates

BACKGROUND

Campylobacter colonise the gastrointestinal tract of warm-blooded animals and are major enteropathogens in humans. C. coli is less common than C. jejuni and accounts for about 10% of the total number of Campylobacter infections although the two species seem to share many virulence determinants. Campylobacter bacteraemia is rare, estimated to occur in less than 1% of the infections, and the exact mechanisms regulating the progression of the infection from the gastrointestinal tract to the blood stream are unclear. Here, we looked at the contribution of C. coli to Campylobacter infections and further compared various virulence traits in C. coli clade 1 blood and stool isolates.

RESULTS

We assessed the numbers of C. jejuni and C. coli among typed isolates in the PubMLST database and found that C. coli accounted for 25.9% of blood isolates, but only 8.9% of the stool isolates. Phylogenetic analysis of 128 C. coli clade 1 whole genome sequences deposited to NCBI revealed no specific clustering of the human blood, stool or animal isolates. Of the six C. coli isolates chosen for phenotypic analyses, stool isolates adhered significantly better to human HT-29 colon cancer cells than the blood isolates, while there was no difference in induced IL-8 levels between the isolates. Furthermore, the stool isolates had two- to fourfold higher RNA expression levels of the flpA, ciaB, iamA and cdt virulence genes than the blood isolates. Finally, we looked at the gene structure of the cdtA, B and C toxin genes and found numerous nucleotide additions and deletions disrupting the open reading frames. In contrast to 58% isolates of animal origin, only 38% and 32% of human blood and stool isolates, respectively, had all three cdt genes intact, a prerequisite to produce functional toxins.

CONCLUSIONS

This study reveals interesting differences between C. coli clade 1 isolates of human and animal origin on one hand, and also between human blood and stool isolates, on the other. The results suggest that C. coli might downregulate and/or inactivate various virulence determinants as the isolates pass from the animal host to the human gastrointestinal tract and enter the human blood stream.

Revealing the Regional Localization and Differential Lung Retention of Inhaled Compounds by Mass Spectrometry Imaging

Background: For the treatment of respiratory disease, inhaled drug delivery aims to provide direct access to pharmacological target sites while minimizing systemic exposure. Despite this long-held tenet of inhaled therapeutic advantage, there are limited data of regional drug localization in the lungs after inhalation. The aim of this study was to investigate the distribution and retention of different chemotypes typifying available inhaled drugs [slowly dissolving neutral fluticasone propionate (FP) and soluble bases salmeterol and salbutamol] using mass spectrometry imaging (MSI). Methods: Salmeterol, salbutamol, and FP were simultaneously delivered by inhaled nebulization to rats. In the same animals, salmeterol-d₃, salbutamol-d₃, and FP-d₃ were delivered by intravenous (IV) injection. Samples of lung tissue were obtained at 2- and 30-minute postdosing, and high-resolution MSI was used to study drug distribution and retention. Results: IV delivery resulted in homogeneous lung distribution for all molecules. In comparison, while inhalation also gave rise to drug presence in the entire lung, there were regional chemotype-dependent areas of higher abundance. At the 30-minute time point, inhaled salmeterol and salbutamol were preferentially retained in bronchiolar tissue, whereas FP was retained in all regions of the lungs. Conclusion: This study clearly demonstrates that inhaled small molecule chemotypes are differentially distributed in lung tissue after inhalation, and that high-resolution MSI can be applied to study these retention patterns.

Altered proportions of circulating CXCR5+ helper T cells do not dampen influenza vaccine responses in children with rheumatic disease

Biological therapy options for the treatment of rheumatic disease target molecules that can affect the cross-talk between innate and adaptive immune responses upon vaccination. Influenza vaccination in children with rheumatic disease has been recommended, but there are only sparse data on the quality of vaccine responses from pediatric patients treated with biological therapy. We conducted an influenza vaccine study over 3 consecutive seasons where the antibody response to TIV was evaluated in children with PRD (n = 78), including both non-treated (n = 17) and treated (with methotrexate, TNF-inhibitors with or without methotrexate, or IL-inhibitors, n = 61) children as well as healthy age-matched controls (n = 24). Peripheral B cells, T and NK cell populations, as well as CXCR5+ (follicular) helper T cells (T_FH) and chemokines involved in antibody responses were assessed prior to immunization in the same cohort. Data on disease duration, therapy and data on previous influenza vaccinations were retrieved. The proportion of circulating T_FH cells were significantly lower in non-treated children with PRD compared to treated patients and healthy controls. The significantly lower proportion of T_FH cells was mirrored by a marked significant increase in CXCL13 serum level, the ligand for CXCR5, with higher levels in non-treated children with PRD compared to treated patients and healthy controls. However, the proportion of T_FH cells or CXCL13 level at the time of vaccination was not a predictor of the antibody response to TIV in this cohort of children. Children with PRD had an overall similar response to TIV as healthy children. Although not significant, children treated with TNF-inhibitors differed as a few children remained seronegative towards H3N2- and influenza B viruses after immunization. Our data show that children with PRD respond to TIV as healthy children. Furthermore, plasma CXCL13 levels did not correlate to the proportion of T_FH cells in blood prior to immunisation, or to antibody responses following immunization.

Homing defects of B cells in HIV-1 infected children impair vaccination responses

BACKGROUND

Successful vaccinations rely on antibody responses. Chemokine receptors play an important role in B cell homing to differentiation niches. We assessed CXCR4, CXCR5 and CCR6 expression on B cells during HIV-1 infection and relate it to antibody responses against a HBV vaccine.

METHODS

Blood was obtained from 54 healthy controls and 38 ART-treated HIV-1 infected children, aviremic (n = 25) or viremic (n = 13). Frequency of naïve and memory B cell subsets was studied by immunostaining. Homing capacity of blood B cells to lymphoid and inflamed tissues was evaluated through CXCR4, CXCR5 and CCR6 expression. Plasma CXCL12 and CXCL13 levels and antibody titers to HBV antigen were determined by ELISA.

RESULTS

The frequency of naïve and resting memory (RM) B cells in ART treated children was comparable to control subjects. Profound defects in the homing phenotypes of naïve and memory B cells were identified, with lower CXCR4 and CXCR5 expression. Increased CXCL13 levels were observed in infected children, inversely correlating to CXCR5 expressing B cell subpopulations. Antibody titers to HBV vaccine correlated with frequency of resting and switched memory B cells in HIV-1 infected children.

CONCLUSIONS

Homing defects of B cells to germinal center may underlie impaired vaccine responses during HIV-1 infection.

Campylobacter coli Clade 3 Isolates Induce Rapid Cell Death In Vitro

Campylobacter bacteria are major human enteropathogens. Campylobacter coli shows less genetic diversity than C. jejuni and clusters into three clades, of which clade 1 includes most human and farm animal isolates, while environmental C. coli isolates mainly belong to clades 2 and 3. Recently, we sequenced the whole genomes of eight C. coli clade 2 and 3 isolates cultivated from water, and here we studied their interaction with human HT-29 colon cancer cells compared to that of clinical clade 1 isolates. All C. coli clade 3 isolates already caused cell necrosis 1 to 2 h after inoculation, whereas none of the clade 1 and 2 isolates analyzed induced cell death. Isolates from clades 2 and 3 adhered to epithelial cells better than clade 1 isolates, but all isolates induced similar levels of interleukin-8 (IL-8). Alignment and phylogenetic analysis of the translated putative virulence genes cadF, flpA, iamA, ciaB, and ceuE revealed clade-specific protein sequence variations, with clade 1 and 2 sequences being more closely related and clade 3 sequences being further apart, in general. Moreover, when RNA levels were measured, clade 3 isolates showed significantly lower levels of expression of cadF, iamA, and ceuE than clade 2 isolates, while flpA expression levels were higher in clade 3 isolates. The cytolethal distending toxin genes were also expressed in clades 2 and 3, although there was no difference between clades. Our findings demonstrate differences between the effects of C. coli clade 1, 2, and 3 isolates on human cells and suggest that C. coli clade 3 might be more virulent than clade 2 due to the observed cytotoxicity.IMPORTANCECampylobacter coli is a common zoonotic cause of gastroenteritis in humans worldwide. The majority of infections are caused by C. coli clade 1 isolates, whereas infections due to clade 2 and 3 isolates are rare. Whether this depends on a low prevalence of clade 2 and 3 isolates in reservoirs important for human infections or their lower ability to cause human disease is unknown. Here, we studied the effects of C. coli clade 2 and 3 isolates on a human cell line. These isolates adhered to human cells to a higher degree than clinical clade 1 isolates. Furthermore, we could show that C. coli clade 3 isolates rapidly induced cell death, suggesting differences in the virulence of C. coli The exact mechanism of cell death remains to be revealed, but selected genes showed interesting clade-specific expression patterns.

Retrospective study showed that blood sampling errors risked children's well-being and safety in a Swedish paediatric tertiary care

AIM

Blood analyses containing preanalytical errors (PAEs) are hazardous for patients. This study investigated the frequency of PAEs in blood analysis and the corresponding quality indicators of the sampling process in Swedish paediatric tertiary care.

METHODS

Data were retrieved from the laboratory at Astrid Lindgren Children's Hospital between 2013 and 2014. Preanalytical blood sampling performance was analysed according to the Six Sigma scale, ranging from 0 to 6 (933 137-3.4 defects per million [DPM]).

RESULTS

Of the 1 148 716 analyses, 61 656 (5.4%) were rejected due to PAEs. The PAEs ranged between hospital specialities from 1.9 to 9.4% (p < 0.001) and work shift times, from 6.0% in the day to 5.7% in the evening and 4.3% at night (p values <0.001). Clotting was the most prominent error (51.3%), affecting mostly haematology and coagulation analyses. Incorrectly filled samples represented almost 25% of all PAEs, with effects on chemistry, haematology and coagulation analyses. The sigma score for the overall preanalytical phase (3.2) corresponded to 44 565 DPM.

CONCLUSION

Samples with PAEs were frequently clotted and insufficiently filled, and the distribution of errors varied within working shifts and specific analyses. The overall quality control in paediatric blood sampling was barely acceptable.

Early central line-associated blood stream infections in children with cancer pose a risk for premature catheter removal

AIM

This study examined the clinical characteristics of central line-associated blood stream infections occurring within 30 days after insertion versus later infections in paediatric cancer patients and the subsequent risk for premature catheter removal.

METHODS

This was a retrospective study of children aged 0-18 years who were diagnosed with cancer from 2013 to 2014 at the Astrid Lindgren Children Hospital, Sweden. Clinical and microbiology data for each patient were collected for 365 days after the central venous catheter (CVC) was inserted.

RESULTS

During the study period, 154 children received a CVC. The overall incidence of central line associated blood stream infections was 2.0 per 1000 catheter days. A total of 108 infectious episodes were identified in 44/154 (29%) patients. Of those, 15/44 children (29%) had an early infection within 30 days and alpha-haemolytic Streptococci and coagulase-negative Staphylococci dominated. Children with early infections were more likely to have a haematological malignancy and to need premature removal of the CVC due to repeated infections.

CONCLUSION

We observed a high prevalence of early CVC associated blood stream infection mainly in patients with haematological malignancies. Our study highlights the importance of preventive measures in reducing infections in paediatric cancer patients.

Brain Tissue Sample Stabilization and Extraction Strategies for Neuropeptidomics

Neuropeptides are bioactive peptides that are synthesized and secreted by neurons in signaling pathways in the brain. Peptides and proteins are extremely vulnerable to proteolytic cleavage when their biological surrounding changes. This makes neuropeptidomics challenging due to the rapid alterations that occur to the peptidome after harvesting of brain tissue samples. For a successful neuropeptidomic study the biological tissue sample analyzed should resemble the premortem state as much as possible. Heat stabilization has been proven to inhibit postmortem degradation by denaturing proteolytic enzymes, hence increasing identification rates of neuropeptides. Here, we describe a stabilization protocol of a frozen tissue specimen that increases the number of intact mature neuropeptides identified and minimizes interference of degradation products from abundant proteins. Additionally, we present an extraction protocol that aims to extract a wide range of hydrophilic and hydrophobic neuropeptides by using both an aqueous and an organic extraction medium.

A call to greater inclusion of gerodontology in the dental curriculum: A narrative review

AIM

This literature review explores the need for greater prominence of gerodontology in the undergraduate dental curriculum, focusing on the significance of gerodontology for dental students on clinical placements.

BACKGROUND

As Australia's population ages the number of dentate older people is increasing. An assessment of the dental profession's preparedness, including that of future providers, is needed to ensure that this public health issue is addressed.

METHODS

A database search was performed in MEDLINE (Ovid), CINAHL and JCU OneSearch. Of the 41 articles identified, 31 were selected for review using a narrative approach.

DISCUSSION

Of the 31 articles reviewed, 12 were Australian, 9 North American and 5 European. Five overarching themes were identified, including preparedness for residential aged care facilities; barriers to oral health services provision; attitudes to aged care; gerodontology as part of a dental school curriculum and service-based learning.

CONCLUSION

There are differences in the gerodontology curricula of dental schools, with a wide variation of clinical exposure to older patients. There is evidence that exposure to gerodontology curriculum prior to treating older people may help dental students feel more prepared for managing patients in aged care. The current marginal status of gerodontology in dental school curricula is in need of review.