Structural and intermediary determinants in sexual health care access in migrant populations: a scoping review.

OBJECTIVES: Addressing migrant population's sexual health needs is essential, given the high vulnerability of this population, especially during migratory trajectories and when accessing health care in destination countries. The aim of this scoping review is to identify and describe the structural and intermediary determinants and their dimensions, which negatively influence sexual healthcare access in migrant population in the world in the last 20 years. STUDY DESIGN: Scoping review. METHODS: The search strategy was carried out in the databases PubMed/MEDLINE, Web of Science, EMBASE, and CINAHL. The inclusion criteria were primary studies published in English or Spanish from 2000 to 2022, describing determinants or barriers to access to sexual health for international migrants, refugees, and asylum seekers. The construction of the results was based on the social determinants of health framework. RESULTS: A total of 44 studies were included. Thirteen categories that negatively affect access to sexual health in migrants were identified-structural determinants: language and communication barriers, religious and cultural values, VIH stigma and discrimination, irregular migration status, financial constraints, racism and discrimination, gender inequalities, and lack of knowledge and awareness about sexuality and sexual health; and intermediary determinants: financial health coverage, privacy and confidentiality, health system navigation; health system and facilities, and psychosocial factors. CONCLUSION: The most relevant dimensions identified as barriers to access to health services were "culture and societal values" and "health system". Identifying the determinants that affect migrants' access to sexual health is relevant for the formulation of public policies with sociocultural relevance and an intersectional and human rights approach.

Effectiveness of preventive intervention programmes aiming to improve oral health in children who have undergone caries-related dental extractions: a rapid review.

OBJECTIVE: To determine the effectiveness of preventive interventions in children who have undergone caries-related dental extractions. METHODS: Rapid review across five databases (CENTRAL, Ovid Medline, Embase, Web of Science and Scopus). Quality was assessed using the Risk of Bias 2 tool. RESULTS: Five studies were included, all randomised controlled trials involving pre-and/or post-extractions activity. Three studies involved oral health education (computer game, motivational interviewing, visual aids), one delivered clinical prevention (fissure sealants), and one an enhanced prevention programme combining additional health education and a clinical intervention (fluoride varnish). Retention was mixed (55%-80% in the intervention groups). Of the three studies measuring caries, all reported less caries development in the test group. However, only a study involving a dental nurse-delivered structured conversation, informed by motivational interviewing, showed an improvement in oral health. Two studies reporting on plaque and gingival bleeding had conflicting results. A study reporting on subsequent dental attendance did not demonstrate a clear improvement. CONCLUSION: Few published studies have explored prevention-based interventions in high caries-risk children requiring dental extractions. Whilst evidence of clinical benefit of preventive interventions in this population is limited, the potential use of contemporary behaviour change techniques appears promising. There is an urgent need for more high-quality longer-term trials using contemporary methodologies.

Effects of mesenchymal stem cell culture on radio sterilized human amnion or radio sterilized pig skin in burn wound healing.

Deep second and third degree burns treatment requires fibroblasts, keratinocytes and other skin cells in order to grow new dermis and epidermis. Cells can proliferate, secrete growth factors and extracellular matrix required to repair the damaged tissue. Radiosterilized human amnion and radiosterilized pig skin have been used as natural origin skin dressings for burned patients. Adipose-derived mesenchymal stem cells can differentiate into fibroblasts and keratinocytes and improve wound-healing progress. These cells can stimulate vascular tissue formation, release growth factors, synthetize new extracellular matrix and immunoregulate other cells. In this study, we developed mesenchymal stem cells-cellularized skin substitutes based from radiosterilized human amnion or pig skin. Third-degree burns were induced in mice animal models to evaluate the effect of cellularized skin substitutes on burn wound healing. Mesenchymal phenotype was immunophenotypically confirmed by flow cytometry and cell viability was close to 100%. Skin recovery was evaluated in burned mice after seven and fourteen days post-coverage with cellularized and non-cellularized sustitutes. Histological techniques and immunofluorescence were used to evaluate re-epithelization and type I collagen deposition. We determined that cellularized-human amnion or cellularized-pig skin in combination with mesenchymal stem cells improve extracellular matrix deposition. Both cellularized constructs increase detection of type I collagen in newly formed mouse skin and can be potentially used as skin coverage for further clinical treatment of burned patients.

Preservation of protective capacity of hyperimmune anti-Stx2 bovine colostrum against enterohemorrhagic Escherichia coli O157:H7 pathogenicity after pasteurization and spray-drying processes.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major etiologic agent that causes bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Shiga toxin (Stx) is the main virulence factor of EHEC responsible for the progression to HUS. Although many laboratories have made efforts to develop an effective treatment for Stx-mediated HUS, a specific therapy has not been found yet. Human consumption of bovine colostrum is known to have therapeutic effects against several gastrointestinal infections because of the peptide and proteins (including antibodies) with direct antimicrobial and endotoxin-neutralizing effects contained in this fluid. We have previously demonstrated that colostrum from Stx type 2 (Stx2)-immunized pregnant cows effectively prevents Stx2 cytotoxicity and EHEC O157:H7 pathogenicity. In this study we evaluated the preservation of the protective properties of hyperimmune colostrum against Stx2 (HIC-Stx2) after pasteurization and spray-drying processes by performing in vitro and in vivo assays. Our results showed that reconstituted HIC-Stx2 colostrum after pasteurization at 60°C for 60 min and spray-dried under optimized conditions preserved specific IgG that successfully neutralized Stx2 cytotoxicity on Vero cells. Furthermore, this pasteurized/dehydrated and reconstituted HIC-Stx2 preserved the protective capacity against EHEC infection in a weaned mice model. The consumption of hyperimmune HIC-Stx2 bovine colostrum could be effective for HUS prevention in humans as well as in EHEC control in calves. However, further studies need to be done to consider its use for controlling EHEC infections.

Editorial - Child oral health; is there anything more to know?

It seems a strange thing to be writing about child oral health in the middle of a virus pandemic that has, in the UK at least, paused all routine dental care. Perhaps not; as thoughts turn to the return of "normal" opera- tion there are concerns over potential ongoing impacts from COVID-19 on health services including stricter infection-control requirements and economic impacts from the lockdown. It invites ridicule to try and predict what will happen in the coming years, but the economic and social impacts are likely to increase vulnerability among the already vulnerable and the delivery of dental care is likely to be more problematic and more expensive. More than ever we need to reduce the burden of avoidable dental disease.

Deprivation and child dental attendance in England: exploring the shape and moderators.

OBJECTIVE: To describe the shape of the relationship between area deprivation and dental attendance (DA) in children aged 5 years and under in England and the modifying effect of caries prevalence, ethnicity, family profile and dentist-to-population ratio. BASIC RESEARCH DESIGN: DA rates were calculated at lower-tier local authority level (LA, n=326) using NHS data for the year to March 2017. LA deprivation was determined by Index of Multiple Deprivation 2015. Caries prevalence was retrieved from the 2016/17 National Dental Epidemiology Programme; ethnicity and family profile from Census 2011 and dentist-to-population ratio from NHS statistics. Fractional polynomial (FP) models explored the shape of the relationship. Multivariable regression models were adjusted for covariates. The effect of moderators was estimated by adjusted marginal effects. CLINICAL SETTING: English Lower-tier LAs. MAIN OUTCOME MEASURE: Shape of the relationship between DA and deprivation and its moderators. RESULTS: Best-fitting second-order FP model (p=0.582) did not provide a better fit for the relationship than the linear model. Therefore, the linear model was selected for final analysis. Deprivation was associated with decreased DA rates (Coefficient=-0.39, 95%CI=-0.53,-0.24; p=⟨0.001); while White ethnicity (Coefficient=0.35, 95%CI=0.29, 0.41; p=⟨0.001), single parenthood (Coefficient = 2.21, 95%CI=0.91,3.51; p=0.001) and caries prevalence (Coefficient =0.34, 95%CI=0.25,0.44; p=⟨0.001) with increased rates. These moderated the relationship. CONCLUSIONS: We hypothesised that the shape of the relationship between deprivation and DA could be curvilinear with higher rates in the extreme ends of deprivation. However, the analysis showed a linear association, moderated by the effect of ethnicity, single parenthood and disease level.

Greater child dental health inequality in England compared to Wales and Northern Ireland, despite lower average disease levels.

INTRODUCTION: Dental caries and inequalities in dental health are major public health concerns. AIM: To report variation in dental caries experience across deprivation quintiles and the magnitude of inequalities between countries. DESIGN: Secondary analyses of cross-sectional data from the 2013 Child Dental Health Survey (CDHS) in England, Wales, and Northern Ireland. MATERIALS AND METHODS: Distribution of dental caries across deprivation quintiles were estimated using as proportions and means. The magnitude of inequalities was calculated using the Relative Index of Inequality (RII). MAIN OUTCOMES: Dental caries experience as indicated by the prevalence (%dmft/DMFT>0) and severity (dmft/DMFT) of 'obvious' and 'clinical' decay experience in both primary and permanent dentitions. RESULTS: Children from more deprived quintiles showed higher prevalence and severity of dental caries. RIIs for dental caries were greater in England than Wales or Northern Ireland, indicating greater relative inequalities despite lower average dental caries experience. The prevalence and severity of dental caries among the most deprived children in England were 1.7 to 3.7 times greater than those of the least deprived. CONCLUSION: There is a deprivation gradient in child dental caries in all three countries, with England showing the greatest inequalities.

Low rates of dental attendance by the age of one and inequality between local government administrative areas in England.

OBJECTIVE: To describe child dental attendance (DA) by 1 year of age in England and its relationship with area deprivation. BASIC RESEARCH DESIGN: Analysis of National Health Service data for the 12 months to June 2017. Deprivation was measured by Index of Multiple Deprivation Rank of Average Score (2015) for upper-tier and unitary local authorities in England (LAs, n=151). DA rates were calculated for children under 1 year (⟨1yr) and children aged 1 year and under (⟨1yr). A Spearman's test assessed strength of association with deprivation. The Slope Index of Inequality (SII) and Relative Index of Inequality (RII) explored equity. CLINICAL SETTING: Upper-tier and unitary LAs in England. MAIN OUTCOME MEASURE: Attending an NHS primary care dental service. RESULTS: DA rates ranged from 0 to 12.3% (Median:2; IQR:1.4,3.9) in children ⟨1yr and from 3.7 to 37.6% (Median:10; IQR:7.4,17) in children ≤1yr. DA rates decreased as deprivation decreased (Spearman=-0.25, p=0.0019 in children ⟨1yr; Spearman=-0.21, p=0.0104 in children ≤1yr). The SII suggested a 2 percentage point difference in DA rate across the deprivation distribution in children ⟨1yr (SII=-0.02, 95% CI=-0.01,-0.04; p=⟨0.001); and a 5 point difference in children ≤1yr (SII=-0.05, 95% CI=-0.02,-0.09; p=0.003). The DA rate in the most deprived LA was 2.1 higher than the least deprived LA (RII=2.1, 95% CI=1.4,3.2; p=⟨0.001) in children ⟨1yr and 1.5 higher (RII=1.5, 95% CI=1.2,2; p=0.004) in children ≤1yr. CONCLUSIONS: DA rates were low for all LAs and only partially explained by deprivation. More deprived LAs were, unexpectedly, more likely to report higher DA rates.

Characterization of pediatric microtia cartilage: a reservoir of chondrocytes for auricular reconstruction using tissue engineering strategies.

The external ear is composed of elastic cartilage. Microtia is a congenital malformation of the external ear that involves a small reduction in size or a complete absence. The aim of tissue engineering is to regenerate tissues and organs clinically implantable based on the utilization of cells and biomaterials. Remnants from microtia represent a source of cells for auricular reconstruction using tissue engineering. To examine the macromolecular architecture of microtia cartilage and behavior of chondrocytes, in order to enrich the knowledge of this type of cartilage as a cell reservoir. Auricular cartilage remnants were obtained from pediatric patients with microtia undergoing reconstructive procedures. Extracellular matrix composition was characterized using immunofluorescence and histological staining methods. Chondrocytes were isolated and expanded in vitro using a mechanical-enzymatic protocol. Chondrocyte phenotype was analyzed using qualitative PCR. Microtia cartilage preserves structural organization similar to healthy elastic cartilage. Extracellular matrix is composed of typical cartilage proteins such as type II collagen, elastin and proteoglycans. Chondrocytes displayed morphological features similar to chondrocytes derived from healthy cartilage, expressing SOX9, COL2 and ELN, thus preserving chondral phenotype. Cell viability was 94.6 % during in vitro expansion. Elastic cartilage from microtia has similar characteristics, both architectural and biochemical to healthy cartilage. We confirmed the suitability of microtia remnant as a reservoir of chondrocytes with potential to be expanded in vitro, maintaining phenotypical features and viability. Microtia remnants are an accessible source of autologous cells for auricular reconstruction using tissue engineering strategies.

[Hematological and neurological compromise due to vitamin B12 deficit in infant of a vegetarian mother: case report]. / Compromiso neurológico y hematológico por déficit de vitamina B12 en lactante hijo de madre vegetariana: caso clínico.

INTRODUCTION: Vitamin B12 deficiency is extremely common in strict vegetarians and their variants. Infants of vegetarian mothers have a higher risk of deficiency and are more prone to its effects. OBJECTIVE: To report a case in order to warn people about the importance of suspected vitamin B12 deficiency in children of vegetarian mothers. CASE REPORT: A 12-month old infant, daughter of a longtime vegetarian woman, who presented neurological and hematological compromise due to vitamin B12 deficiency, is discussed. After a short period of parenteral administration of cyanocobalamin and enteral nutrition, the patient evolved with clinical and laboratory improvement, although she still had residual development delay. CONCLUSIONS: Vitamin B12 deficiency is often not suspected by the pediatrician in healthy infants. Clinical manifestations can be nonspecific, such as apathy, food refusal and progressive impairment of psychomotor development. A nutritional anamnesis performed on the mother (with great emphasis on those strict vegetarians) to estimate her reserves in the period prior to, during and after delivery can be critical to detect the risk of this vitamin deficiency in young children.

Vaccination of pregnant cows with EspA, EspB, γ-intimin, and Shiga toxin 2 proteins from Escherichia coli O157:H7 induces high levels of specific colostral antibodies that are transferred to newborn calves.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of intestinal disease and hemolytic uremic syndrome, a serious systemic complication that particularly affects children. Cattle are primary reservoirs for EHEC O157:H7 and the main source of infection for humans. Vaccination of cattle with different combinations of bacterial virulence factors has shown efficacy in decreasing EHEC O157:H7 shedding. It is, therefore, important to demonstrate whether vaccination of pregnant cows with EHEC O157:H7 induces high titers of transferable antibodies to avoid early colonization of calves by the bacteria. In this study we evaluated the ability of EspA, EspB, the C-terminal fragment of 280 amino acids of γ-intimin (γ-intimin C280) and inactivated Shiga toxin (Stx) 2 proteins to induce specific antibodies in colostrum and their passive transference to colostrum-fed calves. Friesian pregnant cows immunized by the intramuscular route mounted significantly high serum and colostrum IgG responses against EspB and γ-intimin C280 that were efficiently transferred to their calves. Antibodies to EspB and γ-intimin C280 were detected in milk samples of vaccinated cows at d 40 postparturition. Significant Stx2-neutralizing titers were also observed in colostrum from Stx2-vaccinated cows and sera from colostrum-fed calves. The results presented showed that bovine colostrum with increased levels of antibodies against EHEC O157:H7 may be obtained by systemic immunization of pregnant cows, and that these specific antibodies are efficiently transferred to newborn calves by feeding colostrum. Hyperimmune colostrum and milk may be an alternative to protect calves from early colonization by EHEC O157:H7 and a possible key source of antibodies to block colonization and toxic activity of this bacterium.

Characterization of the 5' and 3' breakpoints of the Spanish (뫧)0-thalassemia deletion in Mexican patients.

We studied five unrelated Mexican carriers of the Spanish (δß)(0)-thalassemia [(δß)(0)-thal] mutation to characterize the size of the deletion, the 5' and 3' breakpoints and the 5' ß-globin haplotype. Sequence analysis revealed the presence of an 89,548 bp deletion. The δ- and ß-globin genes, two olfactory receptor genes (OR51V1 and OR52A1) and two pseudogenes (OR52Z1P and OR51A1P) were deleted. The 5' breakpoint was located at the same position as previously reported, and the 3' breakpoint was situated 7.0 kb downstream of OR52A1 and 11.7 kb upstream of OR52A5. The Spanish (δß)(0)-thal allele was associated with the 5' haplotype 2 [- + + - +] in the studied patients. Because this mutation is relatively frequent in Spain, and the Mexican population contains a high level of Spanish genetic background, we propose that the mutation in both populations share a common ancestral origin.

Parallel activation of Ca(2+)-induced survival and death pathways in cardiomyocytes by sorbitol-induced hyperosmotic stress.

Hyperosmotic stress promotes rapid and pronounced apoptosis in cultured cardiomyocytes. Here, we investigated if Ca(2+) signals contribute to this response. Exposure of cardiomyocytes to sorbitol [600 mosmol (kg water)(-1)] elicited large and oscillatory intracellular Ca(2+) concentration increases. These Ca(2+) signals were inhibited by nifedipine, Cd(2+), U73122, xestospongin C and ryanodine, suggesting contributions from both Ca(2+) influx through voltage dependent L-type Ca(2+) channels plus Ca(2+) release from intracellular stores mediated by IP(3) receptors and ryanodine receptors. Hyperosmotic stress also increased mitochondrial Ca(2+) levels, promoted mitochondrial depolarization, reduced intracellular ATP content, and activated the transcriptional factor cyclic AMP responsive element binding protein (CREB), determined by increased CREB phosphorylation and electrophoretic mobility shift assays. Incubation with 1 mM EGTA to decrease extracellular [Ca(2+)] prevented cardiomyocyte apoptosis induced by hyperosmotic stress, while overexpression of an adenoviral dominant negative form of CREB abolished the cardioprotection provided by 1 mM EGTA. These results suggest that hyperosmotic stress induced by sorbitol, by increasing Ca(2+) influx and raising intracellular Ca(2+) concentration, activates Ca(2+) release from stores and causes cell death through mitochondrial function collapse. In addition, the present results suggest that the Ca(2+) increase induced by hyperosmotic stress promotes cell survival by recruiting CREB-mediated signaling. Thus, the fate of cardiomyocytes under hyperosmotic stress will depend on the balance between Ca(2+)-induced survival and death pathways.

Characterization of stx2 tubular response in a rat experimental model of hemolytic uremic syndrome.

BACKGROUND/AIMS: In Argentina, hemolytic uremic syndrome (HUS) constitutes the most frequent cause of acute renal failure in children. The aim of our study was to analyze the early tubular response under the effect of Shiga toxin type 2 (Stx2) in a rat experimental model of HUS. METHODS: Adult male Sprague-Dawley rats were injected intraperitoneally with culture supernatant from recombinant Escherichia coli expressing Stx2. Functional, histological, immunohistochemical and Western blot studies were performed at 48 h postinoculation. RESULTS: Renal tubules showed the loss of the epithelial markers E-cadherin and ß-catenin, and an increase in transforming growth factor-ß1 expression. We detected the expression of α-smooth muscle actin in the interstitium and fibrosis in the periglomerular areas. CONCLUSION: Our results indicate that the early tubular response to the effects of Stx2 is related to an immunophenotype change of tubular cells and the presence of mild fibrosis in the interstitium.

[Tracheal intubation quality under remifentanil-propofol with sevoflurane compared with remifentanil-propofol with rocuronium: a randomized double-blind clinical trial]. / Evaluación clínica de la calidad de la intubación endotraqueal con remifentanilo-propofol-sevoflurano comparada con remifentanilo-propofol-rocuronio: ensayo clínico aleatorizado, doble ciego.

OBJECTIVE: To determine whether intubation conditions under remifentanil-propofol plus sevoflurane rather than a nondepolarizing neuromuscular blocker are similar to those obtained when a neuromuscular blocker is used. MATERIAL AND METHODS: In this double-blind controlled trial, 100 patients undergoing outpatient surgery were randomized to 2 groups. Intubation in one group was performed under remifentanil, propofol and sevoflurane. In the other, intubation was performed under remifentanil, propofol, and the nondepolarizing neuromuscular blocker rocuronium. We recorded dysphonia at 24 hours, Cormack-Lehane classification at laryngoscopy, mandibular relaxation, vocal cord position and mobility, and cough or movement during laryngoscopy, on intubation and on cuff inflation. Blood pressure and heart rate before and after tracheal intubation were also recorded. RESULTS: No significant between-group differences were observed in dysphonia 24 hours after surgery, Cormack-Lehane classification at laryngoscopy, mandibular relaxation, the position or mobility of vocal cords, or cough or movement during laryngoscopy, intubation or cuff inflation. After intubation the mean (SD) systolic blood pressure was 119.7 (75.4) mm Hg in the rocuronium group and 97.5 (54.5) mm Hg in the sevoflurane group. Mean heart rate was 80.7 beats/min in the rocuronium group and 66.7 beats/min in the sevoflurane group. The differences were significant (P < .05). CONCLUSIONS: Adequate doses of remifentanil, propofol, and sevoflurane provide intubation conditions that are similar to those achieved by using a nondepolarizing neuromuscular blocker, without exposing patients to additional risk. Avoiding use of a neuromuscular blocker would circumvent the development of complications associated with use of these agents or their antagonists and costs would be lower.

Fabrication and in vitro behavior of dual-function chitosan/silver nanocomposites for potential wound dressing applications.

We report the synthesis and in vitro evaluation of dual-function chitosan-silver nanoparticles (CTS-AgNPs) films with potential applications as wound dressings. We attempted to formulate nanocomposite films with appropriate AgNPs concentrations to simultaneously display antibacterial activity and suitability for cell culture. Nanocomposites were obtained by CTS-mediated in situ chemical reduction of AgNO3. Circular-shape AgNPs (sizes ca. 7-50 nm) well distributed within the CTS matrices were obtained in concentrations from 0.018 to 0.573 wt%. Efficacy (bacteriostatic and bactericidal properties) of CTS-AgNPs films to decrease planktonic and biofilm bacterial growth was AgNPs concentration- and bacteria strain-dependent. Films showed significant antibacterial activity against Gram-negative E. coli and P. aeruginosa and Gram-positive S. aureus. Antibacterial activity against S. epidermidis was moderated. Films suitability for cell culture was characterized using primary human fibroblasts (HF). HF displayed cell viability higher than 90% and the characteristic fusiform morphology of adhered fibroblast upon culture on films with AgNPs concentration ≤ 0.036 wt%. HF cultured on these films also showed positive expression of tropoelastin, procollagen type I and Ki-67, characteristic proteins of extracellular matrix and proliferative cells, respectively. In vitro assays demonstrated that cytocompatibility/antibacterial properties decreased/increased as silver concentration increased, suggesting that CTS-AgNPS nanocomposite films with ≈0.04-0.20 wt% might be considered as potential temporary dual-function wound dressings.

Interferon regulatory factor-1 regulates reconstituted extracellular matrix (rECM)-mediated apoptosis in human mammary epithelial cells.

Interactions between extracellular matrix (ECM) and mammary epithelial cells are critical for mammary gland homeostasis and apoptotic signaling. Interferon regulatory factor-1 (IRF-1) is a transcriptional regulator that promotes apoptosis during mammary gland involution and p53-independent apoptosis. We have recently shown that rapid cell surface tamoxifen (Tam) signaling promotes apoptosis in normal human mammary epithelial cells that were acutely damaged by expression of human papillomavirus type-16 E6 protein (*HMEC-E6). Apoptosis was mediated by recruitment of CREB-binding protein (CBP) to the gamma-activating sequence (GAS) element of the IRF-1 promoter, induction of IRF-1 and caspase-1/-3 activation. Here, we show that growth factor-depleted, reconstituted ECM (rECM), similar to Tam, promotes apoptosis in *HMEC-E6 cells through induction of IRF-1. Apoptosis was temporally associated with recruitment of CBP to the GAS element of the IRF-1 promoter, induction of IRF-1 expression and caspase-1/-3 activation. Small interfering RNA-mediated suppression of IRF-1 protein expression in *HMEC-E6 cells blocked (1) induction of IRF-1, (2) caspase-1/-3 activation and (3) apoptosis. These observations demonstrate that IRF-1 promotes rECM-mediated apoptosis and provide evidence that both rECM and rapid Tam signaling transcriptionally activate IRF-1 through recruitment of CBP to the IRF-1 GAS promoter complex.

Shiga toxin-producing Escherichia coli (STEC) O22:H8 isolated from cattle reduces E. coli O157:H7 adherence in vitro and in vivo.

PROBLEM ADDRESSED: Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. OBJECTIVE: Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. METHODS AND RESULTS: The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro. The three strains carry the adhesins iha, ehaA and lpfO113. E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 (eae+, stx2+) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro. When calves were intragastrically pre-challenged with 108 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. CONCLUSIONS: These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment.

Functional and molecular expression of AQP9 channel and UT-A transporter in normal and preeclamptic human placentas.

Transcellular flux of urea across human placenta may be facilitated by aquaglyceroporins and/or by urea transporters (UT). Previously we have reported the presence of AQP3 and AQP9 in the syncytiotrophoblast of human term placenta (hST). In the present study, we detected a significant uptake of water, urea and mannitol sensitive to mercury and phloretin in explants from normal term placenta, which indicates a functional AQP9. In addition, we observed an increase of AQP9 expression in preeclamptic placenta with a lack of functionality of AQP9 for water and mannitol. Our data showed a molecular and functional expression of UT-A in hST from normal and preeclamptic placentas. In the last case, urea uptake sensitive to phloretin and mercury increased and the UT-A protein seems to be augmented. These results suggest that the increase of urea uptake in preeclamptic pregnancies could be attributed to an increase of expression of UT-A more than AQP9 proteins. In conclusion, our results provide new evidences that suggest the involvement of AQP9 and UT-A in the urea excretion mechanism across hST from mother to fetus in physiological conditions. Much further work is needed to define whether the overexpression of AQP9 plays a direct role either in the pathogenesis or in the adaptative response of preeclampsia.