Colonization Of Surfaces Research Articles

PH and redox dual response nano-suppository for the treatment of ulcerative colitis.

To improve treatment compliance and reach sustained and controlled drug release in the colon, we developed a hollow mesoporous silica nano-suppository that responded to both pH and redox stimuli. Firstly, we prepared hollow mesoporous silica nanoparticles containing disulfide bonds (HMSN-SS) and loaded them with 5-ASA. Secondly, we modified the surface of HMSN-SS with polydopamine (PDA) and chitosan (CS) and molded the suppository, which we named 5-ASA@HMSN-SS-PDA-CS (5-ASA@HSPC). By administering 5-ASA@HSPC rectally, it acted directly on the affected area. CS helped the nanoparticles adhere to the colon's surface, while PDA dissociates from HMSN-SS due to protonation in the acidic environment of the ulcerative colon. The disulfide bonds were destroyed by the reducing environment of the colon, leading to a stable and slow release of encapsulated 5-ASA from the pores of HMSN. Finally, in vitro release experiments and in vivo pharmacokinetic and pharmacodynamic experiments had demonstrated that 5-ASA@HSPC exhibited a slow and steady action at the colonic site, with an excellent safety profile. This novel approach showed great potential in the treatment of ulcerative colitis.

Gut metabolite L-lactate supports Campylobacter jejuni population expansion during acute infection.

How the microaerobic pathogen Campylobacter jejuni establishes its niche and expands in the gut lumen during infection is poorly understood. Using 6-wk-old ferrets as a natural disease model, we examined this aspect of C. jejuni pathogenicity. Unlike mice, which require significant genetic or physiological manipulation to become colonized with C. jejuni, ferrets are readily infected without the need to disarm the immune system or alter the gut microbiota. Disease after C. jejuni infection in ferrets reflects closely how human C. jejuni infection proceeds. Rapid growth of C. jejuni and associated intestinal inflammation was observed within 2 to 3 d of infection. We observed pathophysiological changes that were noted by cryptic hyperplasia through the induction of tissue repair systems, accumulation of undifferentiated amplifying cells on the colon surface, and instability of HIF-1α in colonocytes, which indicated increased epithelial oxygenation. Metabolomic analysis demonstrated that lactate levels in colon content were elevated in infected animals. A C. jejuni mutant lacking lctP, which encodes an L-lactate transporter, was significantly decreased for colonization during infection. Lactate also influences adhesion and invasion by C. jejuni to a colon carcinoma cell line (HCT116). The oxygenation required for expression of lactate transporter (lctP) led to identification of a putative thiol-based redox switch regulator (LctR) that may repress lctP transcription under anaerobic conditions. Our work provides better insights into the pathogenicity of C. jejuni.

Effects of glutamine and omega-3 fatty acids on intestinal neomucosa formation on colon serosa in rats.

Intestinal neomucosa formation is a technique defined for the treatment of short bowel syndrome. This study evaluates the effect of glutamine and omega-3 fatty acids on the growth of intestinal neomucosa on the colonic serosal surface has been evaluated. Thirty-two adult male Sprague-Dawley rats were randomly divided into 4 groups: sham, control, glutamine, and omega-3. Laparotomy was performed on all groups. For rats other than the sham group, a 1-cm full-thickness incision was made 4 cm proximal to the ileocecal valve, and colonic serosal surface was sutured as a serosal patch over these openings. By using the oral gavage technique, the glutamine group was ingested with 200 mg/kg/day of glutamine, and the omega-3 group was ingested with 100 mg/kg/day of omega-3 fatty acids. At the end of 14 days, the rats were euthanized, blood specimens were collected, and intestinal segments, including serosal patches, were excised. Transforming growth factor-beta was significantly lower in the glutamine group compared to the control group. Similarly, fibroblast growth factor-2 was significantly lower in the glutamine group compared to the sham group. Intestinal neomucosa formation was observed in 100% of rats in the glutamine group. In the control and omega-3 groups, intestinal neomucosa formation was observed in 57.1% and 60% of rats, respectively. The inflammatory response, granulation tissue formation, and fibroblastic activity were more severe in the rats of the glutamine and omega-3 groups. The intestinal neomucosa formation is an experimental technique, and both glutamine and omega-3 fatty acids have the potential to positively affect inflammatory response, granulation tissue formation, and fibroblastic activity. Specifically, glutamine has a favorable effect on intestinal neomucosa formation.

Animal evolution at the ocean’s water-air interface

Innovation is a key to evolutionary success and entrance into novel ecosystems.1 Species that float freely at the ocean's surface, termed obligate neuston (also called pleuston, here referred to simply as neuston), include highly specialized taxa from distinct evolutionary lineages that evolved floating morphologies.2 In 1958, Soviet scientist, A.I. Savilov,3 stated that floating animal species are derived from benthic ancestors, rather than species from the adjacent pelagic zone, and that floating morphologies are homologous to benthic attachment structures. To test Savilov's hypothesis, we constructed molecular phylogenies and ancestral states for all major floating groups for which molecular data were available. Our results reveal that four of the five clades examined arose directly from a substrate-attached ancestor, although that substrate was not necessarily the benthos, as Savilov stated, and instead included epibiotic and rafting ancestors. Despite their diverse evolutionary origins, floating animals use gas-trapping mechanisms to remain at the surface,4,5,6 and many of these gas-trapping structures appear to be homologous to substrate attachment structures. We also reconstruct the trophic habits of floating mollusks and their sister species, revealing that prey preference remains conserved upon entering the ocean's surface ecosystem. Colonization of the ocean's surface seems to have occurred through successive evolutionary steps from the seafloor. Our results suggest that these steps often included transitions through epibiotic (where species attach to other living organisms) or rafting (where species attach to floating debris) habits. The water-air interface, despite its unique properties, may, in some ways, be just another substrate.

Extraction of Mucins from the Mammalian Intestinal Tract.

In the intestine, mucus covering the mucosa plays a critical role in maintaining gut homeostasis by protecting the mucosa from invasion by commensal bacteria. The gut mucus is composed primarily of MUC2 mucin secreted by goblet cells. MUC2 is highly O-glycosylated, and O-glycans are necessary for the function and polymer structure of MUC2. In addition, recent evidence revealed that several glycan modifications, such as sialylation and sulfation, confer resistance of mucins to proteolysis and affect the viscosity and lubricity of mucus. Therefore, characterizing glycan structures of mucins is required to understand their functions fully. In this chapter, we describe how to purify secreted mucins from the mammalian intestine for analysis of their glycan structures. This description includes the extraction of MUC2 mucin from the mucosal surface of the mouse colon and colon explants.

Nano-topography and functionalization with the synthetic peptoid GN2-Npm9 as a strategy for antibacterial and biocompatible titanium implants

In recent years, antimicrobial peptides (AMPs) have attracted great interest in scientific research, especially for biomedical applications such as drug delivery and orthopedic applications. Since they are readily degradable in the physiological environment, scientific research has recently been trying to make AMPs more stable. Peptoids are synthetic N-substituted glycine oligomers that mimic the structure of peptides. They have a structure that does not allow proteolytic degradation, which makes them more stable while maintaining microbial activity. This structure also brings many advantages to the molecule, such as greater diversity and specificity, making it more suitable for biological applications. For the first time, a synthesized peptoid (GN2-Npm9) was used to functionalize a nanometric chemically pre-treated (CT) titanium surface for bone-contact implant applications. A preliminary characterization of the functionalized surfaces was performed using the contact angle measurements and zeta potential titration curves. These preliminary analyses confirmed the presence of the peptoid and its adsorption on CT. The functionalized surface had a hydrophilic behaviour (contact angle = 30°) but the hydrophobic tryptophan-like residues were also exposed. An electrostatic interaction between the lysine residue of GN2-Npm9 and the surface allowed a chemisorption mechanism. The biological characterization of the CT_GN2-Nmp9 surfaces demonstrated the ability to prevent surface colonization and biofilm formation by the pathogens Escherichia coli and Staphylococcus epidermidis thus showing a broad-range activity. The cytocompatibility was confirmed by human mesenchymal stem cells. Finally, a bacteria-cells co-culture model was applied to demonstrate the selective bioactivity of the CT_GN2-Nmp9 surface that was able to preserve colonizing cells adhered to the device surface from bacterial infection.

Efficacy of biofilm disrupters against Candida auris and other Candida species in monomicrobial and polymicrobial biofilms

AbstractCandida species are now considered global threats by the CDC and WHO. Candida auris specifically is on the critical pathogen threat list along with Candida albicans. In addition, it is not uncommon to find Candida spp. in a mixed culture with bacterial organisms, especially Staphylococcus aureus producing polymicrobial infections. To eradicate these organisms from the environment and from patient surfaces, surface agents such as chlorhexidine (CHD) and Puracyn are used. Biofilm disrupters (BDs) are novel agents with a broad spectrum of antimicrobial activity and have been used in the management of chronic wounds and to sterilise environmental surfaces for the past several years. The goal of this study was to evaluate BDs (BlastX, Torrent, NSSD) and CHD against Candida spp. and S. aureus using zone of inhibition assays, biofilm and time‐kill assays. All BDs and CHD inhibited C. auris growth effectively in a concentration‐dependent manner. Additionally, CHD and the BDs showed excellent antimicrobial activity within polymicrobial biofilms. A comparative analysis of the BDs and CHD against C. auris and C. albicans using biofilm kill‐curves showed at least 99.999% killing. All three BDs and CHD have excellent activity against different Candida species, including C. auris. However, one isolate of C. auris in a polymicrobial biofilm assay showed resistance/tolerance to CHD, but not to the BDs. The fungicidal activity of these novel agents will be valuable in eradicating surface colonisation of Candida spp, especially C. auris from colonised environmental surfaces and from wounds in colonised patients.

Comparative Study of Deterioration in Built Heritage in a Coastal Area: Barbanza Peninsula (Galicia, NW Spain)

The Barbanza Peninsula (Galicia, NW Spain) is located on the west coast of Galicia. It is a narrow tongue of terrain with an area of 416 km2 and a high altitudinal gradient, with the top having a maximum height of more than 600 m at a distance of less than 5 Km from the sea. As a result of this, there is a significant rainfall gradient (from 900 to more than 3300 mm per year). In the peninsula, there are valuable historical buildings built with granite rock that show variable decay patterns. In this work, we have considered 14 of them, located in several parts of the peninsula, and we have studied their deterioration patterns. Some of them are close to the sea, with sea salt being a possible cause of decay, while for those located far from the sea, the high humidity and rainfall can be the most important cause of decay. A macroscopic study was carried out to determine the deterioration patterns. We have also analyzed the possible role of salts in the decay by using X-ray fluorescence as a screening technique to assess the presence of salts and the possible correlation of salts with the distance to the sea and using scanning electron microscopy to directly identify salts in some of the buildings. The most frequently reported decay is due to lichen growth (biological colonization). Depending on the proximity to the coast, the study area was divided into two zones: zone 1, closer to the sea (<1 km), with an important influence of sea salts and wind, and zone 2, further from the sea, with higher altitudes (center of the peninsula) and important rainfall, humidity, and therefore, biological colonization of stone surfaces. Crusts (to a lesser degree, because it is a mainly rural area) are more frequent in zone 1, but the state of conservation of stone in zone 1 is better than that in zone 2, possibly due to the concentration of urban centers in this zone and more interventions for cleaning stone surfaces. Finally, although we did not observe clear patterns in the appearance of salts in the buildings in agreement with the distance to the sea, we observed different patterns of salts in two of the buildings, one in each zone, which clearly show that, to some extent, salts are involved in decay.

Characterization of fungal species involved in white haze disorder on apples in Northern Italy and description of Golubevia mali sp. nov. and Entyloma mali sp. nov.

White haze, caused by an extensive fungal colonization of the apple surface, is an emerging postharvest issue in several European apple production areas. It results in compromised quality and decreased marketability of the fruits, leading to economic losses. In this study, the occurrence and the diversity of white haze-related fungi associated with apples was investigated in Northern Italy. Fungal strains were isolated from apple tissues and the species diversity was assessed using molecular and phylogenetic tools. Moreover, the ability of the isolated species to reproduce symptoms on healthy apples artificially inoculated was tested. Seventy-two fungal isolates were collected. Six species belonging to different basidiomycetous genera (Entyloma, Golubevia, Tilletiopsis) were identified, showing high diversity of fungi involved in white haze development in Northern Italy. The strains were identified as E. belangeri, E. randwijkense, G. pallescens, T. washingtonensis. Moreover, two new species, E. mali sp. nov. and G. mali sp. nov. were described. The most frequently isolated strains were inoculated on healthy apple fruit, showing to be able to reproduce symptoms on red-skin apples, fulfilling Koch’s postulates. This work provides new insights to increase knowledge about the causal agents of white haze on apple. In addition, the names Golubevia, Golubeviaceae and Golubeviales have been nomenclaturally validated.

Actinobacillus pleuropneumoniae, surface proteins and virulence: a review

Actinobacillus pleuropneumoniae (App) is a globally distributed Gram-negative bacterium that produces porcine pleuropneumonia. This highly contagious disease produces high morbidity and mortality in the swine industry. However, no effective vaccine exists to prevent it. The infection caused by App provokes characteristic lesions, such as edema, inflammation, hemorrhage, and necrosis, that involve different virulence factors. The colonization and invasion of host surfaces involved structures and proteins such as outer membrane vesicles (OMVs), pili, flagella, adhesins, outer membrane proteins (OMPs), also participates proteases, autotransporters, and lipoproteins. The recent findings on surface structures and proteins described in this review highlight them as potential immunogens for vaccine development.

Surface Conditioning Effects on Submerged Optical Sensors: A Comparative Study of Fused Silica, Titanium Dioxide, Aluminum Oxide, and Parylene C

Optical sensors excel in performance but face efficacy challenges when submerged due to potential surface colonization, leading to signal deviation. This necessitates robust solutions for sustained accuracy. Protein and microorganism adsorption on solid surfaces is crucial in antibiofilm studies, contributing to conditioning film and biofilm formation. Most studies focus on surface characteristics (hydrophilicity, roughness, charge, and composition) individually for their adhesion impact. In this work, we tested four materials: silica, titanium dioxide, aluminum oxide, and parylene C. Bovine Serum Albumin (BSA) served as the biofouling conditioning model, assessed with X-ray photoelectron spectroscopy (XPS). Its effect on microorganism adhesion (modeled with functionalized microbeads) was quantified using a shear stress flow chamber. Surface features and adhesion properties were correlated via Principal Component Analysis (PCA). Protein adsorption is influenced by nanoscale roughness, hydrophilicity, and likely correlated with superficial electron distribution and bond nature. Conditioning films alter the surface interaction with microbeads, affecting hydrophilicity and local charge distribution. Silica shows a significant increase in microbead adhesion, while parylene C exhibits a moderate increase, and titanium dioxide shows reduced adhesion. Alumina demonstrates notable stability, with the conditioning film minimally impacting adhesion, which remains low.

Influence of the Phase Composition of Titanium Alloys on Cell Adhesion and Surface Colonization.

The pivotal role of metal implants within the host's body following reconstructive surgery hinges primarily on the initial phase of the process: the adhesion of host cells to the implant's surface and the subsequent colonization by these cells. Notably, titanium alloys represent a significant class of materials used for crafting metal implants. This study, however, marks the first investigation into how the phase composition of titanium alloys, encompassing the volume fractions of the α, β, and ω phases, influences cell adhesion to the implant's surface. Moreover, the research delves into the examination of induced hemolysis and cytotoxicity. To manipulate the phase composition of titanium alloys, various parameters were altered, including the chemical composition of titanium alloys with iron and niobium, annealing temperature, and high-pressure torsion parameters. By systematically adjusting these experimental parameters, we were able to discern the distinct impact of phase composition. As a result, the study unveiled that the colonization of the surfaces of the examined Ti-Nb and Ti-Fe alloys by human multipotent mesenchymal stromal cells exhibits an upward trend with the increasing proportion of the ω phase, concurrently accompanied by a decrease in the α and β phases. These findings signify a new avenue for advancing Ti-based alloys for both permanent implants and temporary fixtures, capitalizing on the ability to regulate the volume fractions of the α, β, and ω phases. Furthermore, the promising characteristics of the ω phase suggest the potential emergence of a third generation of biocompatible Ti alloys, the ω-based materials, following the first-generation α-Ti alloys and second-generation β alloys.

Field Study of Activity of Antimicrobial Polypropylene Textiles

In this work, an in situ study is presented of the impact of textile materials used in healthcare facilities on microbial colonization of textile surfaces. The available literature describes antimicrobial active textiles and their effectiveness in laboratory conditions. However, the quantification of the impact on the microbiome of healthcare facilities has not been investigated so far. Polypropylene yarns doped with silver phosphate glass and zinc pyrithione were prepared and used for the production of bed sheets and clothing for healthcare personnel. Subsequently, measurements of airborne particles and viable microorganisms on given textiles were conducted in a private surgery clinic for 3 weeks, comparing the counts of viable microorganisms before and after replacing staff clothing and bedding on examination and the surgical bed with said polypropylene cloth. A significant reduction in airborne particles and viable microorganisms was expected based on previous studies on the use of polypropylene textiles in operating rooms. In this study, a significant reduction in viable airborne fungi and viable microorganisms on monitored textiles was observed by multiple methods. However, the effect on airborne microorganisms seems insignificant in areas with frequent patient traffic. The textile described here represents a new additional way of protecting patients and medical personnel from healthcare-associated infections while using a modification of proven production procedures and commercially usable materials without legislative restrictions.

The adhesin SCF1 mediates Candida auris colonization

Candida auris is an emerging human fungal pathogen that can rapidly spread and cause outbreaks of invasive infections. Santana et al. discovered that a novel surface colonization factor (SCF1), and a conserved adhesin, Iff4109, mediates C. auris colonization on abiotic surfaces, skin, and virulence in vivo.

Comparative analysis of the oral opportunistic microorganism growth on the surface of collagen membranes: experimental study

Relevance. Nowadays, in oral surgery, it is still relevant to increase the effectiveness of collagen membranes in the oral cavity in the condition of potential microbial contamination of the wound.Purpose. The study aimed to conduct a comparative analysis of the growth of opportunistic oral bacteria on various collagen membranes.Material and methods. Based on the I.I. Mechnikov Research Institute for Vaccines and Sera, the study conducted a comparative analysis of the growth of opportunistic oral bacteria on the surface of resorbable collagen membranes developed by the Institute of Regenerative Medicine of the Sechenov University and an already existing foreign alternative. Microbial growth was assessed for S. aureus, S. mutans and C. albicans as the most significant microorganisms isolated from the oral cavity. The quantitative composition of microorganisms was analyzed in the control group without membranes and in groups with membranes (Group 2 – customized collagen membrane 2, Group 3 – membrane 3 with recombinant human lactoferrin, Group 4 – Mucograft membrane) on days 3, 5, and 7 from the start of membrane surface colonization. In all groups, we also evaluated the pH change in a 10% sucrose solution under the influence of biofilm microorganisms. Statistical data processing included the calculation of mean, standard deviations and medians, and comparison between groups was carried out using the Kruskal-Wallis test after assessing the samples' distribution normality. The results were statistically significant at a minimum of 95%.Results. The performed analysis showed statistically significant differences in the quantitative composition of the microbial biofilm on the surface of all three membranes. The developed collagen membrane with lactoferrin showed the best result at all times, while the customized collagen membrane did not significantly differ from the Mucograft membrane in CFU values and medium pH change. This provision was statistically significant for all three studied microorganisms.Conclusion. The study showed the potential of using manufactured collagen membranes to eliminate soft tissue defects in the oral cavity under the condition of their surfaces' possible contamination as an alternative to foreign membranes.

Skin Microbiome Composition and Key Factors of its Barrier Function

The skin is the largest organ of the human body, it creates protective barrier between the internal and external environment. Skin barrier damage may result in homeostasis imbalance, inflammation, or bacterial infection. The microbiome plays a crucial role in maintaining normal skin functioning: control of pathogenic diversity of microorganisms, stimulate immune cells, and modulate chronic dermatoses development. There are various mechanisms for restoring skin barrier function. They are associated with the microorganisms’ activity. Thus, skin restoration is an important task included in the general concept of atopic dermatitis management. One of such methods is the skin surface colonization with commensals, so significant role is assigned to the new dermatological drugs. The normalization of the microbiome in affected skin areas with cosmetic care products can significantly affect the result of skin barrier restoration.

Wound-healing plasticity enables clonal expansion of founder progenitor cells in colitis.

Chronic colonic injury and inflammation pose high risks for field cancerization, wherein injury-associated mutations promote stem cell fitness and gradual clonal expansion. However, the long-term stability of some colitis-associated mutational fields could suggest alternate origins. Here, studies of acute murine colitis reveal a punctuated mechanism of massive, neutral clonal expansion during normal wound healing. Through three-dimensional (3D) imaging, quantitative fate mapping, and single-cell transcriptomics, we show that epithelial wound repair begins with the loss of structural constraints on regeneration, forming fused labyrinthine channels containing epithelial cells reprogrammed to a non-proliferative plastic state. A small but highly proliferative set of epithelial founder progenitor cells (FPCs) subsequently emerges and undergoes extensive cell division, enabling fluid-like lineage mixing and spreading across the colonic surface. Crypt budding restores the glandular organization, imprinting the pattern of clonal expansion. The emergence and functions of FPCs within a critical window of plasticity represent regenerative targets with implications for preneoplasia.

Association of patient clinical and gut microbiota features with vancomycin-resistant enterococci environmental contamination in nursing homes: a retrospective observational study

Preventing transmission is crucial for reducing infections with multidrug-resistant organisms (MDROs) in nursing homes. To identify resident characteristics associated with MDRO spread, we investigated associations between patient characteristics and contamination of their proximate room surfaces with vancomycin-resistant enterococci (VRE). In this retrospective observational study, we used demographic and clinical data (including data on comorbidities, physical independence, catheter use within the past 30 days, and antibiotic exposure within the past 30 days) and surveillance cultures of patient body sites and room surfaces at enrolment and during weekly follow-up visits within the first month, and monthly thereafter (up to 6 months), in six US nursing homes collected in a previous clinical trial (September, 2016, to August, 2018). We did 16S rRNA gene sequencing on perirectal surveillance swabs to investigate the association between the gut microbiota and the culture status of participants and their rooms. We included 245 participants (mean age 72·5 years [SD 13·6]; 111 [45%] were men, 134 [55%] were women, 132 [54%] were non-Hispanic white, and 112 [46%] were African American). We collected 2802 participant samples and 5592 environmental samples. At baseline, VRE colonisation was present in 49 (20%) participants, with environmental surfaces being contaminated in 36 (73%) of these patients. Hand contamination among VRE-colonised participants was more common in those with environmental contamination compared with those without (50 [51%] of 99 vs seven [13%] of 55; p<0·0001). We found a correlation between hand contamination and both groin and perirectal colonisation and contamination of various high-touch room surfaces (Cohen's κ 0·43). We found participant microbiota composition to be associated with antibiotic receipt within the past 30 days (high-risk antibiotics p=0·011 and low-risk antibiotics p=0·0004) and participant VRE colonisation status, but not environmental contamination among VRE-colonised participants (participant only vs uncolonised p=0·071, both participant and environment vs uncolonised p=0·025, and participant only vs participant and environment p=0·29). Multivariable analysis to identify independent factors associated with VRE-colonised participants contaminating their environment identified antibiotic exposure (adjusted odds ratio 2·75 [95% CI 1·22-6·16]) and male sex (2·75 [1·24-6·08]) as being associated with increased risk of environmental contamination, and physical dependence as being associated with a reduced risk of environmental contamination (0·91 [0·83-0·99]). Our data support antibiotic use and interaction with proximal surfaces by physically independent nursing home residents as under-appreciated drivers of environmental contamination among VRE-colonised residents. Integrating resident hand-hygiene education and antimicrobial stewardship will strengthen efforts to reduce MDROs in nursing homes. US Centers for Disease Control and Prevention, National Institute of Health, Canadian Institutes of Health Research, and University of Michigan.

Estradiol mediates colonic epithelial protection in aged mice after stroke and is associated with shifts in the gut microbiome

ABSTRACT The gut is a major source of bacteria and antigens that contribute to neuroinflammation after brain injury. Colonic epithelial cells (ECs) are responsible for secreting major cellular components of the innate defense system, including antimicrobial proteins (AMP) and mucins. These cells serve as a critical regulator of gut barrier function and maintain host-microbe homeostasis. In this study, we determined post-stroke host defense responses at the colonic epithelial surface in mice. We then tested if the enhancement of these epithelial protective mechanisms is beneficial in young and aged mice after stroke. AMPs were significantly increased in the colonic ECs of young males, but not in young females after experimental stroke. In contrast, mucin-related genes were enhanced in young females and contributed to mucus formation that maintains the distance between the host and gut bacteria. Bacterial community profiling was done using universal amplification of 16S rRNA gene sequences. The sex-specific colonic epithelial defense responses after stroke in young females were reversed with ovariectomy and led to a shift from a predominately mucin response to the enhanced AMP expression seen in males after stroke. Estradiol (E2) replacement prior to stroke in aged females increased mucin gene expression in the colonic ECs. Interestingly, we found that E2 treatment reduced stroke-associated neuronal hyperactivity in the insular cortex, a brain region that interacts with visceral organs such as the gut, in parallel to an increase in the composition of Lactobacillus and Bifidobacterium in the gut microbiota. This is the first study demonstrating sex differences in host defense mechanisms in the gut after brain injury.

Evaluation of the Antifungal Activity of Heat-Cured Soft Denture Liner Impregnated with Chitosan Nanoparticles

The most serious problem of the resilient denture lining materials is colonization and penetration of the soft-liner surface by Candia albicans and related Candida species. So, this research was oriented to check the antifungal effect of Chitosan nanop articles (CHs NPs) incorporated into heat-cured acrylic soft liners. 60 specimens were prepared, 30 specimens for disk diffusion test and other 30 specimens for viable count of C. albicans test. The specimens split into six groups depending on different percentages of Chitosan NPs addition: 0.5wt%, 1.5wt%, 2.5wt%, 3.5wt%, 4.5wt%, and control group withou t addition 0%). For disk diffusion test, the autoclaved soft lining samples were fitted into sterilized Petri dish containi ng Mueller Hinton agar upon which candidal suspension were swabbed then fitted the samples on the agar surface, in cubated for 24 hrs. Then the inhibition zones were measured by utilizing digital caliper ruler. For viable count test, t he autoclaved samples of soft liner were submersion in sterilized tubes containing Sabouraud dextrose broth in which a small amount of candidal suspension, incubated for 24hrs. The Results of the disk-diffusion test showed the highest mean value of the inhibition zone at 3.5wt% group follow ed by 4.5wt% group and there was no inhibition zone for control and other experimental groups. Furthermore, the vi ability test indicated the colony forming units of C. albicans were decrease as the percentage of CHs NPs increased. With limitation of this study, it was concluded the CHs NPs considered as a strong antifungal agent and the impregnation of the chitosan nanoparticles into soft liner that help to form a soft lining material with antifungal activity and minimal candida associated infection.