Are there new biomarkers of the gastroduodenal microbiota useful in the diagnosis of coeliac disease in children? A pilot study

The changing of microbiome could precede the development of coeliac disease (CeD). We compared the bacterial profile of microbiota of tissues collected simultaneously from the stomach and duodenum in newly diagnosed patients with CeD. Biopsies were collected from 60 children and adolescents aged 2-18 years: (1) 40 patients with CeD; (2) 20 children as control group. The evaluation of the bacterial microbiota was carried out by sequencing the V3-V4 regions of the 16S rRNA subunit, using next-generation sequencing (NGS). The composition of bacterial microbiota was correlated with clinical and blood parameters. The beta diversity analysis revealed a significant dissimilarity in the gastric samples between the CeD and control group (Bray-Curtis index, P = 0.008, and weighted UniFrac distance, P = 0.024). At L2 (phylum level), Campylobacterota was only present in the stomach of the CeD group. A comparison of the abundance of bacteria between the stomach and duodenum showed significant differences in 10 OTUs (operational taxonomic units) in the control and 9 OTUs in the CeD group at L6 (genus) and in 8 OTUs and in 6 OTUs, respectively, at L7 (species). A significant correlation was observed between the genus Novosphingobium in stomach of CeD group and possession of the DQ2.5 and DQ 8 allele, and in the duodenum - between the DQ 8 allele and the species Blautia wexlerae. Significant differences in selected, little-known genera of bacteria suggest their potential role as new biomarkers in the development of CeD. To fully understand the mechanism of CeD development in genetically predisposed individuals, it is necessary to take into account not only the abundance of a given genus or species of bacteria, but also the anatomical location of its occurrence.

A pilot randomized trial of the body advocacy movement: a novel, dissonance-based intervention designed to target fear of weight gain and anti-fat bias in young adults

The Body Advocacy Movement (BAM) is a novel, cognitive-dissonance-based intervention designed to target fatphobia and anti-fat bias as mechanisms to drive reductions in eating disorder (ED) risk. Previous dissonance-based programs (i.e. the Body Project; BP) have successfully targeted thin-ideal internalization as an intervention mechanism. As burgeoning research indicates that fatphobia and anti-fat bias may play a central role in the maintenance of ED pathology, a focused intervention designed to target these constructs could bolster prevention efforts. The aims of this pilot study include confirming acceptability and feasibility of BAM and developing preliminary estimates of its effects on intervention targets, along with benchmarking these effects against the BP intervention. BAM was found to be accepted by participants and feasible to facilitate in a peer-led model. Preliminary results from 50 participants (BAM: N = 26; BP: N = 24) reveal small-to-moderate pre-to-post intervention effects on fatphobia, anti-fat bias, thin-ideal internalization, and eating pathology, which dissipated at 8-week follow-up. The BAM intervention has the potential to supplement the existing suite of ED prevention programs by specifically targeting anti-fat bias, though additional testing in larger and more diverse samples is necessary to clarify its impact on both hypothesized risk mechanisms and ED outcomes.

Direct oral and fiber-derived butyrate supplementation as an anti-obesity treatment via different targets

BACKGROUND & AIMS

Butyric (one of the short-chain fatty acids), a major byproduct of the fermentation of non-digestible carbohydrates (e.g. fiber), is supposed to have anti-obesity and anti-inflammatory properties. However, butyrate's potential and mechanism in preventing obesity and the efficient form of administration remain to be clarified.

METHODS

Hence, we studied the effect of oral supplementation with 5% (w/w) sodium butyrate and 4% (w/w) β-glucan (fiber) on young male mice (C57BL/6J) with high-fat diet-induced obesity (HFD: 60 kcal% of fat + 1% of cholesterol). Six weeks old mice were fed diets based on HFD or control (AIN-93G) diet with/without supplements for 4 weeks. The unique, interdisciplinary approach combining several Raman-based techniques (including Raman microscopy and fiber optic Raman spectroscopy) and next-generation sequencing was used to ex vivo analyze various depots of the adipose tissue (white, brown, perivascular) and gut microbiome, respectively.

RESULTS

The findings demonstrate that sodium butyrate more effectively prevent the pathological increase in body weight caused by elevated saturated fatty acids influx linked to a HFD in comparison to β-glucan, thereby entirely inhibiting diet-induced obesity. Moreover, butyrate significantly affects the white adipose tissue (WAT) reducing the epididymal WAT mass in comparison to HFD without supplements, and decreasing lipid saturation in the epididymal WAT and perivascular adipose tissue of the thoracic aorta. Contrarily, β-glucan significantly changes the composition and diversity of the gut microbiome, reversing the HFD effect, but shows no effect on the epididymal WAT mass and therefore the weight gain inhibition is not as effective as with sodium butyrate.

CONCLUSIONS

Here, oral supplementation with sodium butyrate and β-glucan (fiber) has been proven to have an anti-obesity effect through two different targets. Administration-dependent effects that butyrate imposes on the adipose tissue (oral administration) and microbiome (fiber-derived) make it a promising candidate for the personalized treatment of obesity.

Determinants of the microbiome spatial variability in chronic rhinosinusitis

BACKGROUND

The sinus microbiome in patients with chronic rhinosinusitis (CRS) is considered homogenous across the sinonasal cavity. The middle nasal meatus is the recommended sampling site for 16S rRNA sequencing. However, individuals with unusually high between-site variability between the middle meatus and the sinuses were identified in previous studies. This study aimed to identify which factors determine increased microbial heterogeneity between sampling sites in the sinuses.

METHODOLOGY

In this cross-sectional study samples for 16S rRNA sequencing were obtained from the middle meatus, the maxillary and the frontal sinus in 50 patients with CRS. The microbiome diversity between sampling sites was analysed in relation to the size of the sinus ostia and clinical metadata.

RESULTS

In approximately 15% of study participants, the differences between sampling sites within one patient were greater than between the patient and other individuals. Contrary to a popular hypothesis, obstruction of the sinus ostium resulted in decreased dissimilarity between the sinus and the middle meatus. The dissimilarity between the sampling sites was patient-specific: greater between-sinus differences were associated with greater meatus-sinus differences, regardless of the drainage pathway patency. Decreased spatial variability was observed in patients with nasal polyps and extensive mucosal changes in the sinuses.

CONCLUSIONS

Sampling from the middle meatus is not universally representative of the sinus microbiome. The differences between sites cannot be predicted from the patency of communication pathways between them.

Alterations in intestinal Archaea composition in pediatric patients with Crohn's disease based on next-generation sequencing - a pilot study

Intestinal dysbiosis can lead to the induction of systemic immune-mediated inflammatory diseases, such as Crohn's disease Although archaea are part of the commensal microbiota, they are still one of the least studied microorganisms. The aim of our study was the standardization of the optimal conditions and primers for sequencing of the gut archaeome using Next Generation Sequencing, and evaluation of the differences between the composition of archaea in patients and healthy volunteers, as well as analysis of the changes that occur in the archaeome of patients depending on disease activity. Newly diagnosed patients were characterized by similar archeal profiles at every taxonomic level as in healthy individuals (the dominance of Methanobacteria at the class level, and Methanobrevibacter at the genus level). In turn, in patients previously diagnosed with Crohn's disease (both in active and remission phase), an increased prevalence of Thermoplasmata, Thermoprotei, Halobacteria (at the class level), and Halococcus, Methanospaera or Picrophilus (at the genus level) were observed. Furthermore, we have found a significant correlation between the patient's parameters and the individual class or species of Archaea. Our study confirms changes in archaeal composition in pediatric patients with Crohn's disease, however, only in long-standing disease. At the beginning of the disease, the archeal profile is similar to that of healthy people. However, in the chronic form of the disease, significant differences in the composition of archaeome begin to appear. It seems that some archaea may be a good indicator of the chronicity and activity of Crohn's disease.

Three generations of mTOR kinase inhibitors in the activation of the apoptosis process in melanoma cells

Many signaling pathways are involved in the mammalian target of rapamycin (mTOR), and this serine/threonine kinase regulates the most important cellular processes such as cell proliferation, autophagy, and apoptosis. The subject of this research was the effect of protein kinase inhibitors involved in the AKT, MEK, and mTOR kinase signaling pathways on the expression of pro-survival proteins, activity of caspase-3, proliferation, and induction of apoptosis in melanoma cells. The following inhibitors were used: protein kinase inhibitors such as AKT-MK-2206, MEK-AS-703026, mTOR-everolimus and Torkinib, as well as dual PI3K and mTOR inhibitor-BEZ-235 and Omipalisib, and mTOR1/2-OSI-027 inhibitor in single-mode and their combinations with MEK1/2 kinase inhibitor AS-703026. The obtained results confirm the synergistic effect of nanomolar concentrations of mTOR inhibitors, especially the dual PI3K and mTOR inhibitors (Omipalisib, BEZ-235) in combination with the MAP kinase inhibitor (AS-703026) in the activation of caspase 3, induction of apoptosis, and inhibition of proliferation in melanoma cell lines. Our previous and current studies confirm the importance of the mTOR signal transduction pathway in the neoplastic transformation process. Melanoma is a case of a very heterogeneous neoplasm, which causes great difficulties in treating this neoplasm in an advanced stage, and the standard approach to this topic does not bring the expected results. There is a need for research on the search for new therapeutic strategies aimed at particular groups of patients. Effect of three generations of mTOR kinase inhibitors on caspase-3 activity, apoptosis and proliferation in melanoma cell lines.

New insights into diversity of the upper respiratory tract microbiota and its relationship with SARS-CoV-2 viral load in the nasopharyngeal epithelial cells in patients with COVID-19

INTRODUCTION

The effects of SARS‑CoV‑2 infection on the composition of the upper respiratory tract (URT) microbiota are yet to be established, and more attention to this topic is needed.

OBJECTIVES

The study aimed to assess the bacterial profile and the possible association between the URT microbiota composition and the SARS‑CoV‑2 viral load.

PATIENTS AND METHODS

Nasopharyngeal swabs were taken from 60 adult patients with SARS‑CoV‑2 infection who were divided into 3 groups based on the quantification cycle (Cq) value in the quantitative polymerase chain reaction test: group I (n = 20), Cq lower than or equal to 31 (high replication rate); group II (n = 20), Cq greater than 31 and lower than 38 (low replication rate), and group III (n = 20), Cq higher than or equal to 38 (virus eliminated from the nasopharyngeal epithelial cells). The obtained genetic libraries of 16S rRNA were sequenced and taxonomic diversity profiling was performed to determine the α- and β‑biodiversity in each group.

RESULTS

A significantly lower abundance of Prevotella species was noted in group I, as compared with groups II and III. Akkermansia muciniphila, Faecalibacterium prausnitzii, Fusicatenibacterium saccharivorans, and Bacteroides dorei abundance was characteristic of and significantly greater in group I than in groups II and III. Overall, the microbiota composition was the most diverse in group I, whereas groups II and III were more homogenous in terms of taxonomic diversity.

CONCLUSIONS

The arbitrary division of patients according to the SARS‑CoV‑2 viral load was reflected in diverse composition of their bacterial microbiota, which implies an association between these 2 factors. The patients with a low viral replication rate and those who eliminated the virus from the epithelial cells belonged to a group with a less diverse microbiota community than the patients with a high viral replication rate.

Changes in the gut mycobiome in pediatric patients in relation to the clinical activity of Crohn's disease

BACKGROUND

Numerous studies have shown that in Crohn’s disease (CD), the gut microbiota is of great importance in the induction and maintenance of inflammation in the gastrointestinal tract. Until recently, studies have focused almost exclusively on bacteria in the gut. Lately, more attention has been paid to the role of intestinal fungi.

AIM

To study the gut mycobiome analysis of pediatric patients with CD (in different stages of disease activity) compared to healthy children.

METHODS

Fecal samples were collected from patients: With active, newly diagnosed CD (n = 50); active but previously diagnosed and treated CD (n = 16); non-active CD and who were in clinical remission (n = 39) and from healthy volunteers (n = 40). Fungal DNA was isolated from the samples. Next, next generation sequencing (MiSeq, Illumina) was performed. The composition of mycobiota was correlated with clinical and blood parameters.

RESULTS

Candida spp. were overrepresented in CD patients, while in the control group, the most abundant genus was Saccharomyces. In CD patients, the percentage of Malassezia was almost twice that of the control (P < 0.05). In active CD patients, we documented a higher abundance of Debaryomyces hansenii (D. hansenii) compared to the non-active CD and control (P < 0.05) groups. Moreover, statistically significant changes in the abundance of Mycosphaerella, Rhodotorula, and Microidium were observed. The analyses at the species level and linear discriminant analysis showed that in each group it was possible to distinguish a specific species characteristic of a given patient population. Moreover, we have documented statistically significant correlations between: D. hansenii and patient age (negative); C. zeylanoides and patient age (positive); C. dubliniensis and calprotectin (positive); C. sake and calprotectin (positive); and C. tropicalis and pediatric CD activity index (PCDAI) (positive).

CONCLUSION

Mycobiome changes in CD patients, and the positive correlation of some species with calprotectin or PCDAI, give strong evidence that fungi may be of key importance in the development of CD.

Comparison of iSeq and MiSeq as the two platforms for 16S rRNA sequencing in the study of the gut of rat microbiome

Abstract

Amplicon-based next-generation sequencing (NGS) of the 16S ribosomal RNA (16S) regions is a culture-free method used to identify and analyze Procaryota occurring within a given sample. The prokaryotic 16S rRNA gene contains conserved regions and nine variable regions (V1-V9) frequently used for phylogenetic classification of genus or species in diverse microbial populations. This work compares the accuracy and efficacy of two platforms, iSeq and MiSeq from Illumina, used in sequencing 16S rRNA. The most important similarities and differences of 16S microbiome sequencing in 20 fecal rat samples were described. Genetic libraries were prepared according to 16S Metagenomic Sequencing Library Preparation (Illumina) for the V3 and V4 regions of the 16S. The species richness obtained using iSeq technology was lower compared to MiSeq. At the second taxonomy level (L2), the abundance of taxa was comparable for both platforms. At the L7, the taxa abundance was significantly different, and the number of taxa was higher for the MiSeq. The alpha diversity was lower for iSeq than for MiSeq, starting from the order to the species level. The beta diversity estimation revealed statistically significant differences in microbiota diversity starting from the class level to the species level in samples sequenced on two investigated platforms. This work disclosed that the iSeq platform could be used to evaluate the bacterial profile of the samples to characterize the overall profile. The MiSeq System seems to be better for a detailed analysis of the differences in the microbiota composition.

Key points

• iSeq platform allows to shorten the sequencing time three times compared to the MiSeq.

• iSeq can only be used for an initial and quick microbiome assessment.

• MiSeq is better for a detailed analysis of the differences in the microbiota composition.

Supplementary information

The online version contains supplementary material available at 10.1007/s00253-022-12251-z.

Immunoreactivity of acetylcholinesterase and M1 muscarinic receptors in the hippocampus and striatum of rats treated with Rebaudioside A

Rebaudioside A (RebA) is a steviol glycoside used for production of sweeteners. It was shown that the glycosides affect memory and learning processes. The aim of the study was to investigate neurons immunoreactive for acetylcholinesterase (AChE) and M1 muscarinic receptors (mAChRs-M1) of the hippocampal CA1 and CA3 fields and striatal caudateputamen (CP) and globus pallidus (GP) in rats receiving RebA. RebA was administrated to adult rats for 45 days in dilutions of 1 mg and 2 mg RebA/ml water. Indirect peroxidase-antiperoxidase immunohistochemical reaction was conducted on frontal sections containing the hippocampus and striatum with use of antibodies against AChE and mAChRs-M1. Immunoreactive for the studied proteins neurons were morphologically and morphometrically assessed in hippocampal CA1 and CA3 fields and in CP and GP. Microscopic observations did not reveal significant changes in morphology of immunoreactive neurons, which suggests no neurotoxic effect of the studied glycoside on these cells. Morphometric analyses revealed an increase in the density of AChE and mAChRs-M1 immunoreactive neurons. A decrease in reaction intensity of AChE-positive neurons was also demonstrated in the hippocampal CA1 field and in GP. In contrast, an increase in reaction intensity of mAChRs-M1-positive neurons was found in CA1, CA3 fields and in CP and GP. The results of our preliminary studies indicate that RebA administrated to rats has an impact on cholinergic neurons in the studied area. The results suggest a possible increase in the activity of the cholinergic system, responsible for memory and learning processes, after administration of RebA.

Changes in Diet and Anthropometric Parameters in Children and Adolescents with Celiac Disease-One Year of Follow-Up

Celiac disease (CD) may cause numerous nutrient deficiencies that a proper gluten-free diet (GFD) should compensate for. The study group consists of 40 children, aged 8.43 years (SD 3.5), on average, in whom CD was diagnosed on the basis of clinical symptoms, immunological and histopathological results. The patients' height, weight, diet and biochemical tests were assessed three times: before diagnosis, after six months, and following one year of GFD. After one year, the patients' weight and height increased but nutritional status (body mass index, BMI percentile) did not change significantly. The children's diet before diagnosis was similar to that of the general Polish population: insufficient implementation of the dietary norm for energy, fiber, calcium, iodine, iron as well as folic acid, vitamins D, K, and E was observed. Over the year, the GFD of the children with CD did not change significantly for most of the above nutrients, or the changes were not significant for the overall assessment of the diet. Celiac patients following GFD may have a higher risk of iron, calcium and folate deficiencies. These results confirm the need for personalized nutritional education aimed at excluding gluten from the diet, as well as balancing the diet properly, in patients with CD.

Antibacterial and Antifungal Properties of Silver Nanoparticles-Effect of a Surface-Stabilizing Agent

The biocidal properties of silver nanoparticles (AgNPs) prepared with the use of biologically active compounds seem to be especially significant for biological and medical application. Therefore, the aim of this research was to determine and compare the antibacterial and fungicidal properties of fifteen types of AgNPs. The main hypothesis was that the biological activity of AgNPs characterized by comparable size distributions, shapes, and ion release profiles is dependent on the properties of stabilizing agent molecules adsorbed on their surfaces. Escherichia coli and Staphylococcus aureus were selected as models of two types of bacterial cells. Candida albicans was selected for the research as a representative type of eukaryotic microorganism. The conducted studies reveal that larger AgNPs can be more biocidal than smaller ones. It was found that positively charged arginine-stabilized AgNPs (ARGSBAgNPs) were the most biocidal among all studied nanoparticles. The strongest fungicidal properties were detected for negatively charged EGCGAgNPs obtained using (-)-epigallocatechin gallate (EGCG). It was concluded that, by applying a specific stabilizing agent, one can tune the selectivity of AgNP toxicity towards desired pathogens. It was established that E. coli was more sensitive to AgNP exposure than S. aureus regardless of AgNP size and surface properties.

Virucidal efficacy of different formulations for hand and surface disinfection targeting SARS CoV-2

In the ongoing SARS CoV-2 pandemic, effective disinfection measures are needed, and guidance based on the methodological framework of the European Committee for Standardization (CEN) may enable the choice of effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming ‘virucidal activity against enveloped viruses’ as specified in the European Standard EN 14476 as well as in the German Association for the Control of Viral Diseases/Robert Koch Institute (DVV/RKI) guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in the EN 14476 and DVV/RKI guidelines. Thus, chemical disinfectants claiming ‘virucidal activity against enveloped viruses’ based on the EN 14476 and DVV/RKI guidelines will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

Gut Archaea in the context of human diseases*

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Quantitative changes in selected bacteria in the stool during the treatment of Crohn's disease

PURPOSE

The aim of this study was to determine quantitative changes in selected species of bacteria (Bacteroides fragilis, Lactobacillus fermentum, Lactobacillus rhamnosus, Serratia marcescens) in the stool of patients with Crohn's disease (CD) in the course of induction treatment with exclusive enteral nutrition (EEN) or anti-tumor necrosis factor alpha (Infliximab, IFX) vs. healthy controls (HC).

MATERIALS/METHODS

DNA was isolated from stool samples of CD (n = 122) and HC (n = 17), and quantitative real-time Polymerase Chain Reaction (qPCR) was applied. In both treatment groups, the first stool sample was taken before the start of treatment, and the second 4 weeks after its end: in EEN (n = 48; age (mean; SD) 13.35 ± 3.09 years) and IFX groups (n = 13; age (mean; SD) 13.09 ± 3.76 years).

RESULTS

The only species that showed a statistically significant difference between the two groups of patients before any therapeutic intervention was L. fermentum. Moreover, its number increased after completion of EEN and differed significantly when compared with the HC. In the IFX group the number of L. fermentum decreased during the therapy but was significantly higher than in the HC. The number of S. marcescens in the EEN group was significantly lower than in the controls both before and after EEN.

CONCLUSION

The implemented treatment (EEN or IFX) modifies the microbiome in CD patients, but does not make it become the same as in HC.

Dependence of Colonization of the Large Intestine by Candida on the Treatment of Crohn's Disease

The aim of this study was to determine if there are quantitative differences in Candida fungi between pediatric patients with Crohn’s disease (before and after exclusive enteral nutrition (EEN), and the biologic therapy with anti-tumor necrosis factor alpha – (IFX)), and healthy controls. DNA was isolated from fecal samples and PCR was used to determine the number of fungal cells. Both therapeutic interventions resulted in a statistically significant decrease in Pediatric Crohn’s Disease Activity Index. The numbers of Candida decreased during both therapeutic intervention but the difference was statistically significant for the IFX intervention only (p = 0.045). Moreover, fungi population in both study groups declined during intervention when compared to the control group but the difference was significant before treatment only in the IFX group (p = 0.013). The total distribution of Candida with both IFX and EEN as well as in the control group differed significantly (p = 0.01) before treatment only. No correlation between the numbers of Candida and disease activity as well as the following biochemical parameters: serum iron concentration, protein or glucose level were found. It cannot be ruled out that, in combination with genetic and immunological disorders, fungi can contribute to the initiation of the disease process and perpetuation of active inflammation.

Relative homogeneity of oral bacterial oral in Crohn's disease compared to ulcerative colitis and its connections with antioxidant defense - preliminary report

INTRODUCTION

Interactions between oral microbiota and systemic diseases have been suggested. We aimed to examine the composition of oral microbiota with reference to antioxidative defense and its correlation with clinical state in Crohn's disease (CD) in comparison to ulcerative colitis (UC).

MATERIALS AND METHODS

Smears were taken from the buccal and tongue mucosa of patients with CD, UC and controls, and cultured with classical microbiology methods. Bacterial colonies were identified using matrix-assisted laser desorption/ionization (MALDI) with a time-of-flight analyzer (TOF). Blood morphology and C-reactive protein (CRP) were analyzed in the hospital laboratory. Antioxidative defense potential (FRAP) was determined using spectrophotometry in saliva and serum.

RESULTS

Oral microbiota in CD patients were characterized by lower diversity in terms of the isolated bacteria species compared to UC and this correlated with reduced FRAP in the oral cavity and intensified systemic inflammation. Oral microbiota composition in CD did not depend on the applied treatment. In CD patients, a negative correlation was observed between the FRAP value in saliva and serum and the CRP value in serum. Individual differences in the composition of oral microbiota suggest that different bacteria species may be involved in the induction of oxidative stress associated with a weakening of antioxidative defense in the oral cavity, manifested by ongoing systemic inflammation.

CONCLUSIONS

Analysis of both the state of the microbiota and antioxidative defense of the oral cavity, as well as their referencing to systemic inflammation may potentially prove helpful in routine diagnostic applications and in aiding a better understanding of CD and UC pathogenesis associated with oral microbiota.

Immunoreactivity for calretininin interneurons of the hippocampal CA1 field and dentate gyrus in adult rats after administration of habanero peppers (Capsicum chinense Jacq.)

Calretinin (CR), a calcium-binding protein from EF-hand family, is localised in non-pyramidal GABA-ergic interneurons of the hippocampus. CR takes part in maintaining calcium binding homeostasis, which suggests its neuroprotective role. Hippocampal neurons contain membrane transient receptor potential vanilloid 1 (TRPV1) which binds to capsaicin (CAP) contained in habanero pepper fruits. Few in vivo studies have revealed the effect of CAP on interneurons containing CR. The aim of the present study was to investigate the CR immunoreac- tivity in interneurons of the hippocampal CA1 field and dentate gyrus (DG) in adult rats after intragastric admin- istration of the habanero pepper fruits. Wistar rats received a peanut oil - control group (C), and oil suspension of habanero pepper fruits at doses of 0.025 g dm/kg b.w. - group I and 0.08 g dm/kg b.w. - group II for 28 days. After euthanasia, the brains were collected and embedded in paraffin blocks using a routine histological tech- nique. Frontal hippocampal sections were immunohistochemically stained for CR by using a peroxidase-antiper- oxidase method. CR immunoreactive (CR-IR) interneurons were morphologically and morphometrically ana- lyzed under a light microscope. The results showed similar shapes and distribution of cells in both areas of the brain in group C and I of animals. However, CR-IR interneurons in the hippocampal CA1 field and in DG were occasionally observed in the group II of rats. The results of morphometric studies did not reveal statistically significant differences in the surface area and shape index of cells between examined brain regions from groups I and II compared to group C. Only in group II of rats, an increase in the digital immunostaining intensity of CR-IR interneurons was found in DG. Low number of CR-IR interneurons in the hippocampal CA1 field and in the DG, under the influence of a large dose of habanero pepper fruits containing CAP, may be caused by the activation of TRPV1 receptors and the increase in Ca2+ ions in these cells. This phenomenon may ultimately lead to neuronal death and may disturb neuronal conduction.

The effectiveness of radiant catalytic ionization in inactivation of Listeria monocytogenes planktonic and biofilm cells from food and food contact surfaces as a method of food preservation

AIMS

The aim of the study was to evaluate the microbicidal effectiveness of radiant catalytic ionization (RCI) against Listeria monocytogenes strains in the form of planktonic cells and biofilm on food products and food contact surfaces as a method of food preservation.

METHODS AND RESULTS

The study material comprised six strains of L. monocytogenes, isolated from food. Samples of different types of food available by retail (raw carrot, frozen salmon filets, soft cheese) and the fragments of surfaces (stainless steel AISI 304, rubber, milled rock tiles, polypropylene) were used in the experiment. The obtained results showed the effectiveness of RCI in the inactivation of both forms of the tested L. monocytogenes strains on all the surfaces. The effectiveness of RCI for biofilm forms was lower as compared with planktonic forms. The PRR value ranged from 18·19 to 99·97% for planktonic form and from 3·92 to 70·10% for biofilm.

CONCLUSIONS

The RCI phenomenon induces the inactivation of L. monocytogenes on surfaces of food and materials used in the processing industry to a varying degree, depending on the manner of surface contamination, the properties of the contaminated materials as well as on the origin of the strain and the properties of surrounding dispersive environment in which the micro-organisms were suspended.

SIGNIFICANCE AND IMPACT OF THE STUDY

Searching of new actions aimed at the reduction of the microbial contamination of food and food contact surfaces are extremely important. RCI method has been already described as an effective technique of microbial and abiotic pollution removal from air. However, our studies provide new, additional data related to evaluation the RCI efficacy against microbes on different surfaces, both in planktonic and biofilm form.

LSTrAP: efficiently combining RNA sequencing data into co-expression networks

BACKGROUND

Since experimental elucidation of gene function is often laborious, various in silico methods have been developed to predict gene function of uncharacterized genes. Since functionally related genes are often expressed in the same tissues, conditions and developmental stages (co-expressed), functional annotation of characterized genes can be transferred to co-expressed genes lacking annotation. With genome-wide expression data available, the construction of co-expression networks, where genes are nodes and edges connect significantly co-expressed genes, provides unprecedented opportunities to predict gene function. However, the construction of such networks requires large volumes of high-quality data, multiple processing steps and a considerable amount of computation power. While efficient tools exist to process RNA-Seq data, pipelines which combine them to construct co-expression networks efficiently are currently lacking.

RESULTS

LSTrAP (Large-Scale Transcriptome Analysis Pipeline), presented here, combines all essential tools to construct co-expression networks based on RNA-Seq data into a single, efficient workflow. By supporting parallel computing on computer cluster infrastructure, processing hundreds of samples becomes feasible as shown here for Arabidopsis thaliana and Sorghum bicolor, which comprised 876 and 215 samples respectively. The former was used here to show how the quality control, included in LSTrAP, can detect spurious or low-quality samples. The latter was used to show how co-expression networks are able to group known photosynthesis genes and imply a role in this process of several, currently uncharacterized, genes.

CONCLUSIONS

LSTrAP combines the most popular and performant methods to construct co-expression networks from RNA-Seq data into a single workflow. This allows large amounts of expression data, required to construct co-expression networks, to be processed efficiently and consistently across hundreds of samples. LSTrAP is implemented in Python 3.4 (or higher) and available under MIT license from https://github.molgen.mpg.de/proost/LSTrAP.

Immunoreactivity of arcuate nucleus astrocytes in rats after intragastric administration of habanero peppers (Capsicum Chinese Jacq.)

Habanero pepper fruits contain capsaicin (CAP) characterised by a spicy taste. Astrocytes express vanilloid receptor (TRPV1), which interacts with cannabinoids including CAP. Only a few studies revealed that CAP leads to alterations of the arcuate nucleus (ARC) structures. The aim of this study was to analyse the GFAP (GFAP-IR) and S100β (S100β-IR) immunoreactive astrocytes of ARC in adult rats after intragastric administration of habanero pepper fruits. Adult, Wistar rats received a peanut oil – control group (C) – and oil suspension of habanero pepper fruits at a dose of 0.08 g dm/kg b.w. for 7 days – E1 group – and 28 days – E2 group. After euthanasia, the brains were embedded in paraffin blocks using a routine histological technique. Frontal slices of ARC were immunohistochemically stained for GFAP and S100β using specific antibodies in the peroxidase-antiperoxidase method. Astrocytes of ARC were morphologically and morphometrically analysed under a light microscope. The results of the study did not reveal statistically significant changes in the density of GFAP-IR cells in E1 and E2 groups of rats in comparison with group C. A statistically significant increase in the density of S100β-IR astrocytes was observed in the E1 group and a decrease in the E2 group. Astrocytes with expression of both studied proteins were characterised by morphological alterations in ARC in the E2 group. The obtained results suggest an influence of CAP contained in habanero pepper fruits on the reactivity of astroglia, which may have an impact on the astrocyte-neuron interactions in order to maintain a proper activity of nervous cells in ARC.

Elevated exhalation of hydrogen peroxide in patients with non-small cell lung cancer is not affected by chemotherapy

OBJECTIVES

Reactive oxygen species, which are implicated in the process of carcinogenesis, are also responsible for cell death during chemotherapy (CHT). Therefore, the aim of the study was to evaluate exhaled H₂O₂ levels in non-small cell lung cancer (NSCLC) patients before and after CHT.

METHODS

Thirty patients (age 61.3 ± 9.3 years) with advanced NSCLC (stage IIIB-IV) and 15 age-matched healthy cigarette smokers were enrolled into the study. Patients received four cycles of cisplatin or carboplatin with vinorelbine every three weeks. Before and after the first, second, and fourth cycle, the concentration of H₂O₂ in exhaled breath condensate was measured with respect to treatment response.

RESULTS

At the baseline, NSCLC patients exhaled 3.8 times more H₂O₂ than the control group (0.49 ± 0.14 vs. 0.13 ± 0.03 µmol/L, P < 0.05); this difference persisted throughout the study. CHT had no noticeable effect on exhaled H₂O₂ levels independent of the treatment response (partial remission vs. progressive disease). Pre- and post-CHT cycles of H₂O₂ levels generally correlated positively.

DISCUSSION

The study demonstrated the occurrence of oxidative stress in the airways of advanced NSCLC patients. Exhaled H₂O₂ level was not affected by CHT and independent of treatment results and changes in the number of circulating neutrophils.

HPV vaccine education: enhancing knowledge and attitudes of community counselors and educators

Educational efforts targeting parents of preadolescents may help them make informed decisions about having their children vaccinated against the human papillomavirus (HPV). We conducted a pilot study examining knowledge, attitudes, and beliefs of community-based health educators and counselors who routinely disseminate sexual health and prevention information through counseling and supporting these parents. We evaluated the impact of a single, brief workshop by administering questionnaires before and after the session. The workshop consisted of an educational intervention that was presented orally by an expert in gynecological oncology and was followed by an open discussion period. Following the information and discussion session, improvements were seen in knowledge accuracy, confidence in being able to discuss HPV vaccine issues with parents, greater willingness to recommend the vaccine, and a better understanding of potential barriers to vaccine uptake. These results suggest that health educators and counselors may be better prepared to encourage their clients to make well-informed decisions regarding HPV vaccination.

[The influence of hyperglycemia on functions of endothelial progenitor cells]

The isolation of endothelial progenitor cells changed our understanding of adult blood vessel formation. Recent studies have proven that EPCs functionally contribute to neovasculogenesis and reendothelization of damage blood vessels. It has been shown that patients with diabetes mellitus have decreased numbers of EPCs with impaired activities important to growth of blood vessels. It has been demonstrated that hypoglycemia cause abnormalities in EPCs proliferation, differentiation, adhesion and migration.

Comparison of 3T3 fibroblasts growth on alginate and polyasparagine (PAA) scaffolds in mouse model

INTRODUCTION

The aim of this study was to evaluate polyasparagine (PAA), a new, promising scaffold. PAA was compared with alginate, which is used in cell transplantations and may be regarded as a standard.

MATERIALS AND METHODS

In vitro cell viability on both scaffolds was assessed. C57B1 mice were injected s. c. alginate or PAA with or without 3T3 cells. After two months specimens from sites of injection were examined and blood samples were taken for enzymatic activity estimation. Cathepsin D activity and alpha1-antitrypsin levels were measured.

RESULTS

In vitro cell viability was lowest on PAA and highest in control group. Increase in levels of enzymes measured was observed in response to PAA and alginate and was lower in case of polymer seeded with cells. Increase in alpha1-antitrypsin levels was lower in case of PAA in comparison to alginate. Scaffold degradation in histopathological specimens was visible.

CONCLUSION

The results indicate that PAA implants undergo biodegradation and nonspecific inflammatory response is comparable to alginate.

The influence of staphylococcin T (StT) on the mouse fibroblasts (3T3) viability, an in vitro experiment

Staphylococcin T (StT) is a bacteriocin, which can serve as an antibiotic. The influence of StT on the mammalian cells viability should be examined before its possible applications. The aim of this work was to study the influence of StT on mouse fibroblasts viability in vitro. StT was delivered as a deposit in agar. 3T3 fibroblasts were used in viability tests. Cells were incubated with StT for 24 and 48 h. In the first controls, cells grew without the agar block, in the second controls, the agar block contained no StT. Trypan blue exclusion test was performed. Growth inhibition of sensitive strain SAU-209P was observed after 24 h incubation with cell culture medium containing StT. Antimicrobial activity of StT in culture medium was confirmed even after 2 months. The viability of 3T3 cells in the second control group was 50% lower than in the first and 25% higher than in StT treated group during the first day. It was noticed mechanical damage of growing cells caused by agar blocks. The number of cells cultured with StT was similar to that of second control group after 2 days. There were no changes in morphology of cells in all groups. It follows that StT had unimportant influence on the fibroblasts (3T3) viability in culture. StT may be considered for future animal trails.

[Eyelid conjunctiva can be a potential cells source for conjunctival sack reconstruction purpose]

There is no ideal culture establishing method for the conjunctival sac reconstruction. Two methods of primary conjunctival culture establishing were compared.

MATERIALS AND METHODS

The internal surface of rat's eyelid was used. In the 1st method cells migrate from specimen and attached to the surface of culture plate. In the 2nd method tissue was digested and placed in the flask. Epithelial character of cultured cells was confirmed.

RESULTS

Both methods allow to set up the culture of epithelial cells. Efficiency of enzymatic isolation was higher then growing from previously attached specimen. At the end of the experiment the cultures were similar.

CONCLUSIONS

Both methods allow to establish the primary culture of conjunctival epithelial cells. Eyelid conjunctiva can be a cells source for the conjunctival sack reconstruction purpose.

Questionnaire regarding the knowledge of the rules of organ procurement from cadaveric donors for transplantation directed to the directors of medical institutions in Poland

We assessed the level of knowledge of organ procurement regulations among the directors of medical institutions in Poland. We also sought to promote the objection form, and the activity of the Central Register of Objections. A questionnaire consisting of 10 questions was sent to 381 random medical health care institution directors countrywide. In 89% of surveyed institutions, the written text of the organ procurement regulations was available and 94% of directors knew the forms of objection, but in 26% of institutions the form was not available and in 14% it was never obtainable. In the medical institutions directors' opinions, the estimated number of objections is 13% of the population in Poland. Organ transplantation is a form of treatment most medical institutions are familiar with, but the matter of donation is not as well known as transplantation, as observed in 48% of questioned institutions.

Geography of the referred potential liver recipients and donors in Poland in 2004

Our aim was to assess the accessibility of potential liver recipients to cadaveric organs and the ability of transplant teams to realize recipients needs in Poland in 2004. Our calculations revealed that in Poland the number of cadaveric liver transplants was two to three times lower than in other countries and is insufficient to meet the needs, also the number of referred potential liver recipients is two to three times lower than expected.

The influence of ambroxol and capsaicin on the isolated rabbit bladder wall

Unmyelinated C-fibers endings lye beneath the epithelial layer and release neuropeptides which regulate baseline transepithelial potential difference (PD) and changes of transepithelial potential difference during mechanical stimulation (dPD). Ambroxol can suppress reflexes such as the cough or the corneal reflex which are connected to stimulation of C fibre endings. The study aimed to estimate the influence of ambroxol (ABX) and capsaicin (CAPSA) on PD and dPD in isolated rabbit bladder. The experiments were carried out on 26 bladder specimens of. 2 cm2 surface area each, obtained from 13 rabbits. Ussing apparatus was used. Procedure used for stimulation of sensory receptor involved directing stream onto epithelium. A stimulus lasted 30s, ejecting the 2.5 ml fluid. Amiloride and bumetanide were used to estimate of ionic currents. Each significant reaction was repeated at least 10 times on various specimens. PD ranged between 5 and 10 mV in different experimental conditions. Mechanical stimulation of isolated bladder wall caused increasing dPD about 2 mV defined as hyperpolarization. Application of ABX to the stimulation fluid decreased the hyperpolarization in comparison with control stimulation under conditions of inhibited chloride ion transport. Application of CAPSA to the stimulation fluid decreased the hyperpolarization in comparison with control stimulation under conditions of inhibited sodium ion transport. ABX and CAPSA had no influence on PD after mechanical stimulation. ABX as well as CAPSA influence on transepithelial ion transport pathways in bladder epithelium is dependent on sensory stimulation. ABX can be suspected to suppress bladder contractions.

36-Month follow-up of 75 renal allograft recipients treated with steroids, tacrolimus, and azathioprine or mycophenolate mofetil

OBJECTIVES

The aim of this retrospective study was to assess the incidence of acute rejection episodes (AR), diabetes mellitus (DM), and serum creatinine (SCr) among renal transplant recipients treated with tacrolimus (Tac), steroids (S), and mycophenolate mofetil (MMF) or azathioprine (Aza).

METHODS

Seventy-five renal allograft recipients enrolled in the COSTAMP study were followed for a period of 3 years. Patients were randomized to receive either Tac and MMF (n = 41) or Tac and Aza (n = 34) concomitantly with steroids. Follow-up assessments were performed at 3, 6, 12, 24, and 36 months.

RESULTS

Patient survival at month 36 was 91.18% in the Tac/Aza/S group and 97.56% in the Tac/MMF/S group. Graft survival at month 36 was 82.35% and 85.37%, respectively. During the study period, 22 cases of biopsy-proven AR were diagnosed in 17 patients (22.6%). After 36 months the total number of AR was 11 in the Aza-treated group (32.4%) and 11 in the MMF-treated group (26.8%). DM was diagnosed de novo in 17 individuals (22.6%). During 36 months, 10 patients from Aza-treated group (29.4%) and seven from MMF-treated group developed DM (17.1%). Serum creatinine values were not significantly different in both arms of the study. Comparison of arterial blood pressure and total cholesterol revealed no significant changes in any of the studied groups.

CONCLUSIONS

We conclude that combinations of steroids, tacrolimus, and azathioprine or MMF provide good results with regard to renal function.

The application of Ilizarov's "bone segment transport" method in the treatment of tumors and tumor-like changes in bone

Background. The authors present their own experience in the application of the "bone segment transport" method developed by Ilizarov for filling post-resection bone deficits in the treatment of neoplastic tumors in long bones. Material and method. Our research involved 9 patients: 2 female patients with an average age of 14.5, and 7 male patients with an average age of 16.7. The follow-up time ranged from 2 to 8 years (average 3.4). Of these patients, 5 were treated for giant-cell tumors with varying degrees of malignancy. Among the remaining patients the bone transport method was used in 2 cases of osteogenic sarcoma, 1 case of chondrosarcoma, and 1 case of aneurismatic cyst. The choice of surgical treatment method was made on the basis of the surgical systems of evaluation and classification of tumors in the locomotor apparatus provided by the Musculoskeletal Tumor Society and described by Enneking. Results. The authors discuss the method and the results using the example of three cases: an osteogenic sarcoma, a giant-cell tumor, and an aneurismatic cyst. The outcome for bone tumors treated with the "bone segment transport" method are satisfactory. Conclusions. In our material there were no tumor relapses after the combined treatment program was completed. In addition, the preservation of the limb provides psychological comfort for the patient, for whom the potential loss of the limb is a source of stress, often undermining faith in the good effects of treatment.

[Complications of distraction-compression osteogenesis and their prophylaxis--a clinical report]

The authors present a historical overview of various classifications of distraction osteogenesis complications. Paley's classification as well as the authors' own classification also presented. Basing on the authors' own 10 year experiences with the Ilizarov method, selected complications at different stages of diagnostics, treatment and rehabilitation are presented. The most effective forms of prophylaxis are presented, with special attention given to the surgeon's own experience with the Ilizarov method.

[The influence of osteotomy technique on distraction osteogenesis]

The authors reviewed the clinical results of leg lengthening by distraction osteogenesis, where two different osteotomy techniques were used: classical corticotomy according to Ilizarov or osteoclasis. Evaluation of results of 64 patients were bases on orthopedic examination and detailed X-ray analysis which included criteria assessing osseous regeneration rate. In those cases where osteoclasis was performed bone formation in the distraction gap was faster than in after osteotomy. An accelerated rate of regenerate formation, as well as a more active regenerate remodelling was observed. This allowed to shorten the time of external fixator application and an earlier rehabilitation.

Association of polymorphism of LTalpha and TNF genes with Graves' disease

Graves' disease (GD) is an autoimmune disease, which develops on the basis of an interaction between genetic, environmental and endogenous factors. GD is associated with some HLA genes. Closely linked with them are TNF genes (TNF and LTalpha). Their role in the pathogenesis of GD is still unclear. Two functional polymorphisms within TNF genes include a substitution of G with A in intron I of LTalpha gene and the same one at position -308 in the TNF gene promoter. We carried out a case-control study for the analysis of the contribution of TNF genes to GD in Polish patients. 156 patients with GD diagnosed by clinical data were investigated and compared to 80 healthy persons with negative familial anamnesis. Both TNF and LTalpha were analysed by PCR/Nco I RFLP. The allelic frequency of the rarer TNF2 (A) allele, was 24.7% in GD patients, significantly higher than in healthy persons (9.3%; p<0.0001). The OR was 4.38 for this allele. The frequency of heterozygotes was 41.8% in GD, as compared to 13.6% in the control group. The allelic frequency of the rarer LTB*1 (G) allele was also significantly increased: from 21.9% in the control group to 37.2% in GD patients (p<0.01; OR 2.81). The frequency of heterozygotes was 48.7% in GD, and 28.8% in the control group. The results indicate that TNF genes may contribute to GD in the Polish population.

[ECT versus transcranial magnetic stimulation (TMS): preliminary data of computer modeling]

The essential issue of electroshock therapy (ECT) is the activity of physical stimulus, i.e., the electric current, on the disturbed structures of the brain. ECT sessions--when chronically applied for evoking antidepressive effects--are responsible for the appearance of excessive incitement in the neuronal net in the brain tissue in a form of self-sustaining after-discharge (SSAD) (convulsive attack characteristic for ECT). The study presents the computer research on basic biophysical phenomena of electroshock therapy (flow of electric current in the structures of the head just before convulsive attack). Five-layer 3-D model of the head was created in OPERA-3D (Vector Fields Ltd., Oxford), general 3 dimensional issues solver. Geometrical dimensions and electrophysical properties of each layer correspond with natural properties. The model was subjected to the action of electric stimulation (parameters identical to those applied in clinical conditions). Analysis of the flow in particular layers revealed the crawling/spreading effect present not only in the scalp layer but also in the layer of cerebrospinal fluid. The effect is conditioned by "deeper situated" lesser conduction of electricity-respectively skull bones, brain tissue. Crawling effect is the reason why only 5-15% of the electricity applied on the surface of the head reaches the surface of the brain. Electro-stimulation examinations also showed that the values of the so called density of the current in layers of brain tissue balanced between 1-10 mA/mm2. The current parameters of ECT were effective in evoking subsequent convulsive attack and safe for the brain tissue. The model was subjected to the action of magnetic stimulation according to the parameters of neurologic technique of transcranial magnetic stimulation (TMS). ELECTRA module was used to solve wire-current issues. The examination showed more regular distribution of current vectors in all layers of the head. The density of cerebral cortex was 0.1-1 mA/mm2, confirming markedly lesser current charge than that observed during ECT. The problem of magnetic stimulation efficacy in irritating deep structures of the brain demands further studies.

Chemiluminescence of ABEI-labelled IgG triggered by the N-chloramine-H(2)O(2)-p-iodophenol system

Light is emitted in systems containing N-chloramines or hypochlorite, H(2)O(2) and N-(4-aminobutyl)-N-ethylisoluminol (ABEI). The emission is enhanced by 4-iodophenol (PIP) in alkaline solution (1 mol/L NaOH), while at lower pH range (9-11) PIP is not only inactive but also its presence reduces chemiluminescence (CL) of the monochloramine-H(2)O(2)-ABEI system to the background. Two procedures for ABEI-labelled IgG assays were developed, with PIP in 1 mol/L NaOH and without PIP at pH 11, and the standard curves of free ABEI in these conditions were examined. We suggest also that the oxidative deamination of taurine chloramine leads to the formation of the various carbonyl derivatives and their formation is accelerated in the presence of H(2)O(2), especially in less alkaline solutions (pH 11). Moreover, the formation of enol forms of aldehydes in assay buffers was observed. The yield of the phenoxy radical mediators of ABEI oxidation and the pH-dependent H(2)O(2):HO(2) ratio seems to be decisive for the overall CL in the system examined. The main advantage of this method is that CL does not need precise timing of measurements and assays can be performed over a long period of time (hours) using a plate luminometer.

Oxidative modification of ovalbumin

Stimulated neutrophils (PMNL) are a source of the active oxygen species: O2, H2O2 and HOCl/OCl- which in turn can act on proteins yielding a variety of mixed oxidation products. A system is proposed in which a model protein-ovalbumin (OVA) first undergoes chlorination by HOCl/OCl- and next is oxidised by H2O2. The modification of functional groups (-NH2, -SH, -S-S-, > C = O, Tyr and Trp) in OVA was monitored as well as their accessibility to promote aggregation. Chlorination resulted in additional inter- or intra -S-S- bond formation followed by a decrease in the total sulfhydryl group content. Amino groups were oxidised to carbonyl moieties with a concomitant acidic shift of pI. Formation of chlorotyrosine at the chlorination step was confirmed and its further H2O2-mediated transformation to bityrosine was demonstrated. It has also been confirmed that tryptophan, and not tyrosine, is the first target for chlorination. SDS/PAGE and HPLC profiles revealed that HOCl/OCl- chlorination promotes formation of aggregates stabilised by non covalent bonds. In conclusion, we suggest that a dramatic change in the OVA molecule structure begins when the molar excess of HOCl/OCl- is about 2 per one reactive group in OVA.

[Magnetic brain stimulation in treatment of depression: the search for effective parameters of stimulation]

Transcranial magnetic stimulation seems to evoke an antidepressant effect similar to that of electroshocks. This effect, however, is not accompanied by convulsions. This technique may be regarded as an alternative method of treatment of depression. It may prove as effective as electroshock treatment, but induce no negative phenomena connected with electro-convulsive treatment. Effectiveness of magnetic stimulation depends on selection of physical parameters of the applied magnetic field. In our model the optimum parameters of transcranial stimulation are: magnetic field induction B < or = 2 T stimulation frequency f [symbol: see text]¿50-100 Hz¿ time of single impulse twide [symbol: see text]¿0,1-1 ms¿ time of impulse rise trise [symbol: see text]¿(10)50-200 microseconds¿ time of impulse decline tdecline [symbol: see text]¿(100)200-1000 microseconds¿ total stimulation time ttotal > or = 1 min repetition rate repetition rate = 8-12

Oxidative modification of ovalbumin

Stimulated neutrophils (PMNL) are a source of the active oxygen species: O2, H2O2 and HOCl/OCl- which in turn can act on proteins yielding a variety of mixed oxidation products. A system is proposed in which a model protein-ovalbumin (OVA) first undergoes chlorination by HOCl/OCl- and next is oxidised by H2O2. The modification of functional groups (-NH2, -SH, -S-S-, > C = O, Tyr and Trp) in OVA was monitored as well as their accessibility to promote aggregation. Chlorination resulted in additional inter- or intra -S-S- bond formation followed by a decrease in the total sulfhydryl group content. Amino groups were oxidised to carbonyl moieties with a concomitant acidic shift of pI. Formation of chlorotyrosine at the chlorination step was confirmed and its further H2O2-mediated transformation to bityrosine was demonstrated. It has also been confirmed that tryptophan, and not tyrosine, is the first target for chlorination. SDS/PAGE and HPLC profiles revealed that HOCl/OCl- chlorination promotes formation of aggregates stabilised by non covalent bonds. In conclusion, we suggest that a dramatic change in the OVA molecule structure begins when the molar excess of HOCl/OCl- is about 2 per one reactive group in OVA.