Search

We evaluated risk factors for sporadic Shiga toxin-producing Escherichia coli (STEC) infection among children in Argentina. We conducted a prospective case-control study in 2 sites and enrolled 150 case-patients and 299 controls. The median age of case-patients was 1.8 years; 58% were girls. Serotype O157:H7 was the most commonly isolated STEC. Exposures associated with infection included eating undercooked beef, living in or visiting a place with farm animals, and contact with a child <5 years of age with diarrhea. Protective factors included the respondent reporting that he or she always washed hands after handling raw beef and the child eating more than the median number of fruits and vegetables. Many STEC infections in children could be prevented by avoiding consumption of undercooked beef, limiting exposure to farm animals and their environment, not being exposed to children with diarrhea, and washing hands after handling raw beef. [ABSTRACT FROM AUTHOR]

The adaptive immune response plays a vital role in eliminating infected and aberrant cells from the body. This process hinges on the presentation of short peptides by major histocompatibility complex Class I molecules on the cell surface. Immunopeptidomics, the study of peptides displayed on cells, delves into the wide variety of these peptides. Understanding the mechanisms behind antigen processing and presentation is crucial for effectively evaluating cancer immunotherapies. As an emerging domain, immunopeptidomics currently lacks standardization-there is neither an established terminology nor formally defined semantics-a critical concern considering the complexity, heterogeneity, and growing volume of data involved in immunopeptidomics studies. Additionally, there is a disconnection between how the proteomics community delivers the information about antigen presentation and its uptake by the clinical genomics community. Considering the significant relevance of immunopeptidomics in cancer, this shortcoming must be addressed to bridge the gap between research and clinical practice. In this work, we detail the development of the ImmunoPeptidomics Ontology, ImPO, the first effort at standardizing the terminology and semantics in the domain. ImPO aims to encapsulate and systematize data generated by immunopeptidomics experimental processes and bioinformatics analysis. ImPO establishes cross-references to 24 relevant ontologies, including the National Cancer Institute Thesaurus, Mondo Disease Ontology, Logical Observation Identifier Names and Codes and Experimental Factor Ontology. Although ImPO was developed using expert knowledge to characterize a large and representative data collection, it may be readily used to encode other datasets within the domain. Ultimately, ImPO facilitates data integration and analysis, enabling querying, inference and knowledge generation and importantly bridging the gap between the clinical proteomics and genomics communities. As the field of immunogenomics uses protein-level immunopeptidomics data, we expect ImPO to play a key role in supporting a rich and standardized description of the large-scale data that emerging high-throughput technologies are expected to bring in the near future. Ontology URL: https://zenodo.org/record/10237571 Project GitHub: https://github.com/liseda-lab/ImPO/blob/main/ImPO.owl., (© The Author(s) 2024. Published by Oxford University Press.)

Dual-mode contrast agents (CAs) have great potential for improving diagnostics. However, the effectiveness of CAs is strictly related to both the solution adopted to merge the two agents into a single probe unit, and the ratio between the two agents. In this study, two dual-mode CAs for simultaneous magnetic resonance imaging (MRI) and ultrasound imaging (UI) were assessed. For this purpose, different densities of superparamagnetic iron oxide nanoparticles (SPIONs) were anchored to the external surface of polymer-shelled microbubbles (MBs) or were physically entrapped into the shell. In vitro static and dynamic experiments were carried out with a limited concentration of modified MBs (10 6  bubbles ml -1 ) by avoiding destruction during UI (performed at a peak pressure lower than 320 kPa) and by using a low-field MRI system (with a magnetic flux density equal to 0.25 T). Under these conditions, different imaging techniques, set-up parameters and SPION densities were used to achieve satisfactory detection of the CAs by using both UI and MRI. However, when the SPION density was increased, the MRI contrast improved, whereas the UI contrast worsened due to the reduced elasticity of the MB shell. For both UI and MRI, MBs with externally anchored SPIONs provided better performance than MBs with SPIONs entrapped into the shell. In particular, a SPION density of 29% with respect to the mass of the MBs was successfully tested.

Five hundred and thirty-seven children admitted to Hospital Dr. Notti and diagnosed with invasive pneumococcal disease between 1993 and 2011 were studied. Their median age was 19 months (range= 0-192 months); 34.82% were <1 year old and 23.46%, >60 months old. Pneumonia with or without effusion (48.04%) and meningitis (29.05%) were the most predominant conditions, with a case fatality rate of 6.14%. Identified serotypes corresponded to 14, 5 and 1 in56.86% of cases. Sensitivity to penicillin was observed in99.74% of non-meningeal strains, while sensitivity to ceftriaxone was found in 98.08% ofmeningeal strains. Risk factors inpneumonia with effusionwere associated to age >60 months old, RR: 1.47 (1.06-2.04), p= 0.02, to serotype 5, RR: 2.57 (1.71-3.87), p= 0.0001, and to serotype 1, RR: 1.86 (1.17-2.96), p= 0.014; in the case of meningitis, risk factors were mainly associated to age <1 year old, RR: 2.35 (1.87-3.06), p= 0.0000, and to serotype 18C, RR: 2.19 (1.3-3.7), p= 0.024. Conclusion. Streptococcus pneumonia was a major problem in infants younger than one year old, who predominantly developed meningitis which caused half of deaths, and in children older than 60 months old, who had a prevalence of pneumonia with effusion. Most cases were sensitive to penicillin and ceftriaxone.

Enteroaggregative Escherichia coli (EAEC) is an increasingly recognized cause of diarrhea in children in developing and developed countries. EAEC is recognized by a characteristic aggregative pattern of adherence to human epithelial (HEp-2) cells cultured in vitro. This is the gold standard assay. The aggregative phenotype is associated with the presence of a 65 MDa plasmid (pAA) that also encodes several other putative virulence factors, such as the aggregative adherence fimbria I (AAF/I) and the enteroaggregative heat-stable enterotoxin (EAST1). The objective of this work was to evaluate the application of PCR (polymerase chain reaction) to identify EAEC strains in cases of acute diarrhea. A total of 87 E. coli strains, isolated from patients under 2 years of age with acute diarrhea in Mendoza, Argentina, were characterized by the reference method (HEp-2 assay), and by AAF/I- and EAST1-PCR. PCR sensitivity and specificity in comparison with the cell culture assay showed 94.4% sensitivity and 78.26% specificity. EAST1- and AAF/I-PCR could be recommended as a screening test, applicable to epidemiologic studies.

We report a case of a nine-year old boy with vomiting, abdominal pain and fever, who underwent surgery with a diagnosis of appendicitis in Mendoza and from whom a Shiga toxin-producing Escherichia coli (STEC) O127:H21 strain was recovered. Forty-eight hours after surgery he presented bilious vomiting and two episodes of intestinal bleeding. Laboratory findings included: hematocrit, 35%; blood urea nitrogen, 0.22 g/L. The urinary output was normal. The following day physical examination showed an alert mildly hydrated child, without fever but with distended and painful abdomen. The patient was again submitted to surgery with a diagnosis of intestinal occlusion. Bleeding and multiple adhesions in jejunum and ileum were found. The patient still had tense and painful abdomen and presented two bowel movements with blood; hematocrit fell to 29% and blood urea nitrogen rose to 0.32 g/L. STEC O127:H21 eae(-)/Stx2/Stx2vh-b(+)/E-Hly(+) was isolated from a stool sample. He was discharged after 10 days of hospitalization and no long-term complications such as HUS or TTP were observed. This is the first report, to our knowledge, on the isolation of E. coli O127:H21, carrying the virulence factors that characterize STEC strains, associated to an enterohemorrhagic colitis case. This serotype was previously characterized as a non-classic enteropathogenic E. coli (EPEC). STEC infections can mimic infectious or noninfectious pathologies. Therefore an important aspect of clinical management is making the diagnosis using different criteria thereby avoiding misdiagnoses which have occasionally led to invasive diagnostic and therapeutic procedures or the inappropriate use of antibiotics.

E. coli strains are the major bacterial cause of diarrhea among children under 2 years of age residing in Mendoza, Argentina. Detection of diarrheogenic E. coli is made after coproculture, by agglutination tests using O-group antisera including most enteropathogenic E. coli (EPEC) serogroups and others often isolated in diarrhea. Although there are many O serogroups and H serotypes of E. coli strongly associated with infantile diarrhea, a number of studies have shown differences in the rate of isolation of EPEC between cases and controls using DNA probes. We compared the diagnosis of EPEC infections by traditional serogrouping tests with other detection methods using cell culture, involving the screening of isolates for adherence patterns to HEp-2 cells. A total of 140 isolates from children less than 24 months old with acute, persistent and chronic diarrhea and 40 isolates from controls were recovered. Three distinct patterns of adherence, termed localised (LA), diffuse (DA) and aggregative (EAgg) adherence were found. The fluorescence actin staining assay was used as indicative of the ability of some EPEC strains that produce attaching-effacing (A/E) lesions. Positive serogrouping strains were strongly associated with adherence (P = 0.0001). LA adherence pattern occurred in 11% of cases with acute diarrhea associated with these serogroups (P = 0.001) and children under 12 months (P = 0.0001). The FAS test was positive in 80% of them. EAgg adherence was found only in patients (20% P = 0.0001) and DA occurred both in cases (29%) and controls (2.5% P = 0.0001). Diagnosis of EPEC infections has traditionally been performed by identifying organisms belonging to a number of serogroups or serotypes epidemiologically linked to diarrhea. Evidence is presented in this paper to show that pathogenicity is not restricted to serogroups. Isolation of many adherent strains not belonging to traditional EPEC O serogroups, shows the need for alternative methods to be used to detect and identify E. coli.

Shiga toxin-producing Escherichia coli (STEC) has been associated with pathogenesis of hemolytic uremic syndrome (HUS) worldwide. The aim of the present study was to characterize the HUS cases reported in Mendoza and to determine their association with STEC infection. From July 1994 through June 1996 thirty-six patients with HUS were admitted to Hospital Pediátrico "Dr. HJ Notti" (Mean age 22.8 +/- 14.9 months, 44% females). The children developed HUS following an acute diarrheal illness in 94.4% of the cases. Bloody diarrhea was observed in 83.3% of them. Antimicrobial therapy had been administered to 69.4% of the patients. Most of the patients were well-nourished (88.9%), belong to middle-low socioeconomical condition (91.7%), from urban areas (72.2%) and they were mostly assisted during summer and the beginning of autumn. The acute stage of the disease occurred with presentation of pallor (100%), edema (25%), anuria (38.9%), oliguria (41.7%), hemolytic anemia (97.2%), thrombocytopenia (86.1%) and neurological involvement (41.7%). Twenty-five of them presented the full clinical syndrome. Peritoneal dialysis were performed in 50% and packed blood cell transfusion in 88.9%. The mean days of hospitalization was 15.1 +/- 9.2 [range 1-32]. A 91.7% of the patients recovered renal function, two developed chronic renal failure and one died. Cumulative evidence of STEC infection was found in 19 (86.4%) of 22 HUS patients. STEC O157:H7, biotype C was found in 8 (36.4%). The prevalent Stx type was Stx2 in STEC, free fecal Stx (STMF) and Stx-neutralizing antibodies (a-Stx). In Mendoza, as in the rest of Argentina E. coli O157:H7, biotype C, Stx2 producer is the most frequently detected pathogen in HUS cases.

Since intravascular volume contraction is regarded as an important pathological feature in preeclampsia, it has been proposed that plasma volume expansion could be a therapeutic manoeuver that interrupts the pathogenetic chain of hypovolemia inducing increased vascular resistance. Furthermore, tissue perfusion should be improved and, if albumin is used as plasma expander agent, interstitial edema should also be reduced. We report the results observed in an open pilot study in ten preeclamptic patients treated with daily albumin infusions (0.4 to 1 g/kg) from 7 to 36 days. No acute effects were shown on blood pressure, and the need for antihypertensive therapies did not decrease in the following days. Serial evaluation after at least five or ten days of repeated albumin infusions did not show stable changes in electrolytes excretion, renal clearances, serum protein concentration and hematocrit value, nor in aldosterone, renin and atrial natriuretic peptide basal levels, while proteinuria tended to increase. Uteroplacental and fetoplacental blood flow acutely ameliorated in 3 cases only after albumin 1 g/Kg, but reached basal values again on the next day. The clinical implications are that daily albumin infusions with this schedule dosage do not lower blood pressure and that they are unable to induce stable changes in renal function, uteroplacental and fetoplacental resistance. No maternal complications were observed during the conservative management, but fetal mortality was high (6/10). Given the uncontrolled study, we cannot know whether similar results had been achieved by conventional therapy only.

Three groups of patients with obstruction of the small airways and normal main airways were submitted to study by determining the closing volume and the V max/V curve. In the first group (beginning chronic bronchitis) was noted an alteration of the curve with normal closing volume in almost all the cases; in the second group (asthma in the remission phase) the closing volume was increased and the curve normal in a part of the patients, -while in the other part the closing volume was normal and the curve altered; in the third group (recent heart infarct), a significative increase in the closing volume was noted with a slightly altered curve: improvement of the tests was obtained after administration of diuretics, the improvement being far more noticeable for the closing volume than for the V max/V curve. The closing volume is therefore an extremely sensitive test of the obstruction of the small airways when the obstruction interests before all the basal zones of the lungs. When the resistances of the small airways are irregularly distributed, the determination of the V max/V curve is, conversely, more useful.