Expression of cagA, virB/D Complex and/or vacA Genes in Helicobacter pylori Strains Originating from Patients with Gastric Diseases.

In order to better understand pathogenicity of Helicobacter pylori, particularly in the context of its carcinogenic activity, we analysed expression of virulence genes: cagA, virB/D complex (virB4, virB7, virB8, virB9, virB10, virB11, virD4) and vacA in strains of the pathogen originating from persons with gastric diseases. The studies were conducted on 42 strains of H. pylori isolated from patients with histological diagnosis of non-atrophic gastritis-NAG (group 1, including subgroup 1 containing cagA+ isolates and subgroup 2 containing cagA- strains), multifocal atrophic gastritis-MAG (group 2) and gastric adenocarcinoma-GC (group 3). Expression of H. pylori genes was studied using microarray technology. In group 1, in all strains of H. pylori cagA+ (subgroup 1) high expression of the gene as well as of virB/D was disclosed, accompanied by moderate expression of vacA. In strains of subgroup 2 a moderate expression of vacA was detected. All strains in groups 2 and 3 carried cagA gene but they differed in its expression: a high expression was detected in isolates of group 2 and its hyperexpression in strains of group 3 (hypervirulent strains). In both groups high expression of virB/D and vacA was disclosed. Our results indicate that chronic active gastritis may be induced by both cagA+ strains of H. pylori, manifesting high expression of virB/D complex but moderate activity of vacA, and cagA- strains with moderate expression of vacA gene. On the other hand, in progression of gastric pathology and carcinogenesis linked to H. pylori a significant role was played by hypervirulent strains, manifesting a very high expression of cagA and high activity of virB/D and vacA genes.

Conventional and molecular methods in the diagnosis of community-acquired diarrhoea in children under 5 years of age from the north-eastern region of Poland.

OBJECTIVES: The purpose of this study was to determine the main causative agents of community-acquired acute diarrhoea in children using conventional methods and PCR. METHODS: Stool samples were collected from 100 children under 5 years of age with acute diarrhoea during the autumn-winter period of 2010-2011. Rotaviruses and adenoviruses were detected by the stool antigen immunoassay, and Salmonella spp, Campylobacter spp, Shigella spp, Yersinia enterocolitica, Yersinia pseudotuberculosis, Clostridium difficile, enterotoxigenic Bacteroides fragilis (ETBF), and diarrhoeagenic Escherichia coli were detected by culture methods and PCR. RESULTS: Overall, enteropathogens were identified in 73% of the children. Bacteria, viruses, and mixed infections were noted in 37%, 24%, and 12% of diarrhoeal cases, respectively. The most common enteric pathogens were rotaviruses (31%), followed by C. difficile (17%), Campylobacter jejuni (13%), Salmonella spp (11%), and atypical enteropathogenic Escherichia coli (aEPEC) strains (10%). Compared with culture methods, PCR increased the overall detection frequency of the bacterial enteropathogens by 4%. CONCLUSIONS: The high prevalence of Campylobacter jejuni suggests that the number of campylobacteriosis cases in Poland may be underestimated; this pathogen should be investigated routinely in children with diarrhoea. Moreover, C. difficile might be considered a causative or contributing agent of diarrhoea in 14.8% of children aged >1 year.

Growth factor release from a chemically modified elastomeric poly(1,8-octanediol-co-citrate) thin film promotes angiogenesis in vivo.

The ultimate success of in vivo organ formation utilizing ex vivo expanded "starter" tissues relies heavily upon the level of vascularization provided by either endogenous or artificial induction of angiogenic or vasculogenic events. To facilitate proangiogenic outcomes and promote tissue growth, an elastomeric scaffold previously shown to be instrumental in the urinary bladder regenerative process was modified to release proangiogenic growth factors. Carboxylic acid groups on poly(1,8-octanediol-co-citrate) films (POCfs) were modified with heparan sulfate creating a heparan binding POCf (HBPOCf). Release of proangiogenic growth factors vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and insulin-like growth factor 1 (IGF-1) from HBPOCfs demonstrated an approximate threefold increase over controls during a 30-day time course in vitro. Atomic force microscopy demonstrated significant topological differences between films. Subcutaneous implantation of POCf alone, HBPOCf, POCf-VEGF, and HBPOCf-VEGF within the dorsa of nude rats yielded increased vascular growth in HBPOCf-VEGF constructs. Vessel quantification studies revealed that POCfs alone contained 41.1 ± 4.1 vessels/mm², while HBPOCf, POCf-VEGF, and HBPOCF-VEGF contained 41.7 ± 2.6, 76.3 ± 9.4, and 167.72 ± 15.3 vessels/mm², respectively. Presence of increased vessel growth was demonstrated by CD31 and vWF immunostaining in HBPOCf-VEGF implanted areas. Data demonstrate that elastomeric POCfs can be chemically modified and possess the ability to promote angiogenesis in vivo.

[Norovirus infection in children hospitalized with acute gastroenteritis in northeastern Poland]. / Zakazenia norowirusowe u dzieci hospitalizowanych z ostra biegunka w pólnocno-wschodniej Polsce.

Noroviruses belonging to the family of Caliciviridae are a major cause of acute gastroenteritis in both children and adults. In the current study incidence of norovirus gastroenteritis was estimated in children hospitalized for acute gastroenteritis using commercially available ELISA tests. Epidemiological data were correlated with basic demographic findings. A hundred and forty nine children with acute gastroenteritis were enrolled in the study. Screening for common viruses causing gastroenteritis: rotavirus and adenovirus was performed and than stool samples were frozen and stored in <20 degrees C for future simultaneous testing with IDEIA Norovirus (Dakocytomation). Group I noroviruses were found in one child when 16 children were tested positive for Norowirus group two. In total noroviruses were found in 11.4% of children included in the study. Children with norovirus infection were 3 weeks to 15 years old (mean age 5.9 years). Seasonal peak of norovirus infection was seen in September through December. The infectious agent has not been identified in 43% of investigated children. Our results support important role of noroviruses as a causing agent of gastroenteritis in children in Northeastern Poland. The importance of noroviruses may grow as rotavirus infections are likely to be eliminated due to wide introduction of vaccine in the nearest future. Routine testing for noroviruses should be considered in clinical practice.

Directional movement of dendritic macromolecules on gradient surfaces.

A gradient-driven methodology has been developed to manipulate the movement of dendritic macromolecules. Poly(propyleneimine) dendrimers, labeled with rhodamine B, are attached to glass substrates via multiple imine bonds. The dendrimers are able to move on the surface by the hydrolysis and re-formation of these imine bonds. In the absence of an external stimulus, this random movement results in a two-dimensional diffusion on the substrate. We are able to bias the movement of these nanoparticles by means of an aldehyde gradient on the glass substrate.

Covalent microcontact printing of proteins for cell patterning.

We describe a straightforward approach to the covalent immobilization of cytophilic proteins by microcontact printing, which can be used to pattern cells on substrates. Cytophilic proteins are printed in micropatterns on reactive self-assembled monolayers by using imine chemistry. An aldehyde-terminated monolayer on glass or on gold was obtained by the reaction between an amino-terminated monolayer and terephthaldialdehyde. The aldehyde monolayer was employed as a substrate for the direct microcontact printing of bioengineered, collagen-like proteins by using an oxidized poly(dimethylsiloxane) (PDMS) stamp. After immobilization of the proteins into adhesive "islands", the remaining areas were blocked with amino-poly(ethylene glycol), which forms a layer that is resistant to cell adhesion. Human malignant carcinoma (HeLa) cells were seeded and incubated onto the patterned substrate. It was found that these cells adhere to and spread selectively on the protein islands, and avoid the poly(ethylene glycol) (PEG) zones. These findings illustrate the importance of microcontact printing as a method for positioning proteins at surfaces and demonstrate the scope of controlled surface chemistry to direct cell adhesion.

[Acute viral gastroenteritis in children]. / Ostre biegunki wirusowe u dzieci.

The article presents common etiologic agents of viral gastroenteritis in children. The actual knowledge on molecular characteristics of rotaviruses, noroviruses, sapoviruses, astroviruses, and adenoviruses as well as their epidemiology in the world and Poland is reviewed. The authors emphasize the need of greater use of molecular procedures (RT-PCR) for detection the common serotypes of rotavirus and other viral agents of gastroenteritis in Polish children. Familiarity with molecular epidemiology of viruses and with their antigenic diversity allows to elaborate and apply the adequate vaccines as well as to initiate the prophylactic procedures.

[Clostridium difficile toxin A and other enteropathogens in stool specimens of children hospitalized due to acute diarrhoea]. / Toksyna A Clostridium difficile i inne enteropatogeny w kale dzieci hospitalizowanych z powodu ostrej biegunki.

A total of 74 fresh stool specimens obtained from children with acute diarrhoea (43) and without diarrhoea (31) were examined simultaneously for bacteria pathogens (culture methods) and for Clostridium difficile toxin A (Oxoid Toxin A Kits) and enteric viruses (only diarrhoeal samples) (Slidex Rota-Adeno Kits; bioMçrieux). One (49%) or dual with C. difficile (23%) enteric pathogens associated with community-acquired diarrhoea (58% bacteria and 14% viruses) in 31 (72%) children were recognized. Clostridium difficile associated diarrhoea (CDAD) (18,6%) and Salmonella enterica subsp. enterica serovar Enteritidis (16,3%) the most commonly were observed. Children were considered to have CDAD if they met special criteria such as the positive test for C. difficile toxin A, the presence of diarrhoea for at least 2 days and no other documented enteric pathogens. It was be found that antibiotic usage in the previous 3 weeks as a main risk factor for CDAD not be frequent (only 2/8 CDAD). The frequency of C. difficile toxin A detection in the diarrhoeal stool specimens from children treated or not treated with antibiotics was comparable (p>0,05); this same observed when stool specimens from children without diarrhoea were tested. The frequency of toxin A detection in stool specimens from children with acute diarrhoea (41,9%) and without diarrhoea (54,8%) was comparable (p>0,05) also. In conclusion, we recommended detection of toxin A by C. difficile toxin A Test as the rapid screening in diarrhoeal stool specimens only because the high predictive value of a negative test and the high sensitivity for CDAD with special criteria were found.