Juan R. Velazquez

Utility of Stool Sample-based Tests for the Diagnosis of Helicobacter pylori Infection in Children

Objective:Helicobacter pylori antigen or DNA in stool are meant to detect the bacteria; however, in children the colonization of the gastric mucosa by H pylori is usually weak and fecal excretion of antigen or DNA varies considerably, challenging the utility of these tests in this age group. The aim of the present study was to carry out a systematic review and meta-analysis to evaluate the performance of stool H pylori DNA and antigen tests for the diagnosis of infection in children. Methods:We conducted a systematic review and meta-analysis to assess the accuracy of stool tests for diagnosis of H pylori infection in children. We searched PubMed, EMBASE, and LILACS databases. Selection criteria included participation of at least 30 children and the use of a criterion standard for H pylori diagnosis. In a comprehensive search, we identified 48 studies. Results:Regarding antigen-detection tests, enzyme-linked immunosorbent assay (ELISA) monoclonal antibodies showed the best performance, with sensitivity and specificity of 97%, positive likelihood ratio (LR+) of 29.9, and negative likelihood ratio (LR−) of 0.03. ELISA polyclonal antibodies had sensitivity of 92%, specificity of 93%, LR+ of 16.2, LR− of 0.09, and high heterogeneity (P < 0.0001). One-step monoclonal antibody tests demonstrated sensitivity of 88%, specificity of 93%, LR+ of 10.6, and LR− of 0.11. For DNA detection, polymerase chain reaction–based test showed sensitivity of 80.8%, specificity of 98%, LR+ of 17.1, and LR− of 0.18. Conclusions:Detection of H pylori antigen in stools with ELISA monoclonal antibodies is a noninvasive efficient test for diagnosis of infection in children. One-step tests showed low accuracy and more studies are needed to obtain a useful office-based screening test. The available molecular tests are still unreliable.

The role of macrophages and mast cells in lymphangiogenesis and angiogenesis in cervical carcinogenesis.

During carcinogenesis it is known that growth factors and cytokines from stromal and inflammatory cells from the microenvironment promote angiogenesis and lymphangiogenesis. However, the participation of macrophages and mast cells in these processes is not well understood. The aim of this study was to evaluate the relationship between mast cell and macrophage density with blood and lymphatic vessels in various stages of carcinoma of the uterine cervix. Tissue sections from archival paraffin-embedded samples from cases with cervical intraepithelial neoplasias (CIN) 1, 2, 3, carcinoma in situ, and invasive carcinoma were used. Immunohistochemical staining was done using the following antibodies: anti-LYVE-1; anti-CD31; anti-CD68, and anti-tryptase. Our results showed a significant increase in the number of macrophages in carcinoma in situ, a correlation between lymphatic vessels and macrophages in premalignant lesions CIN 2, and a correlation between mast cells and blood vessels in both CIN 2 and carcinoma in situ. In conclusion, our data underscore the importance of the recruitment of macrophages and mast cells in the development of tumor-associated blood and lymphatic capillaries.

Risk factors and prognosis for neonatal sepsis in southeastern Mexico: analysis of a four-year historic cohort follow-up.

BackgroundNeonatal sepsis is a worldwide public health issue in which, depending on the studied population, marked variations concerning its risk and prognostic factors have been reported. The aim of this study was to assess risk and prognostic factors for neonatal sepsis prevailing at a medical unit in southeastern Mexico. Thus, we used a historic cohort design to assess the association between a series of neonates and their mothers, in addition to hospital evolution features and the risk and prognosis of neonatal sepsis (defined by Pediatric Sepsis Consensus [PSC] criteria) in 11,790 newborns consecutively admitted to a Neonatology Service in Mérida, Mexico, between 2004 and 2007.ResultsSepsis was found in 514 of 11,790 (4.3%) newborns; 387 of these cases were categorized as early-onset (<72 h) (75.3%) and 127, as late-onset (>72 h) (24.7%). After logistic regression, risk factors for sepsis included the following: low birth weight; prematurity; abnormal amniotic fluid; premature membrane rupture (PMR) at >24 h; respiratory complications, and the requirement of assisted ventilation, O2 Inspiration fraction (IF) >60%, or a surgical procedure. Some of these factors were differentially associated with early- or late-onset neonatal sepsis. The overall mortality rate of sepsis was 9.5%. A marked difference in the mortality rate was found between early- and late-onset sepsis (p >0.0001). After Cox analysis, factors associated with mortality in newborns with sepsis comprised the following: prematurity; low birth weight; low Apgar score; perinatal asphyxia, and the requirement of any invasive medical or surgical procedure.ConclusionsThe incidence of neonatal sepsis in southeastern Mexico was 4.3%. A different risk and prognostic profile between early- and late-onset neonatal sepsis was found.

Chemokine (C-X-C Motif) Ligand 12/Stromal Cell-Derived Factor-1 Is Associated With Leukocyte Recruitment in Asthma

BACKGROUND Asthma is characterized by allergic airway inflammatory response involving extensive leukocyte infiltration. The stromal cell-derived factor (SDF)-1 or chemokine (C-X-C motif) ligand 12 (CXCL12) attracts a number of cells, including resting T lymphocytes, monocytes, CD34(+) stem cells, basophils, and mature eosinophils. To date, however, the potential role of CXCL12/SDF-1 in relation to leukocyte recruitment in asthma has not been previously examined, to our knowledge. METHODS Levels of CXCL12/SDF-1 in the BAL fluid (BALF) of 15 subjects with asthma and 13 healthy subjects were measured by enzyme-linked immunosorbent assay. Immunohistochemistry was performed to identify the cellular source of this chemokine. RESULTS CXCL12/SDF-1 concentrations were significantly elevated in BALF from subjects with asthma compared with normal subjects (median 845 pg/mL, range, 296-1,700 pg/mL vs median 55 pg/mL, range 25-97 pg/mL; P < .001). Concentrations of CXCL12/SDF-1 correlated with macrophages (r = 0.728, P < .01), lymphocytes (r = 0.651, P < .01), and eosinophils (r = 0.765, P < .01). By immunohistochemistry, CXCL12/SDF-1 was localized to the airway epithelium and to a lesser extent to mononuclear cells. CONCLUSION CXCL12/SDF-1 is released in high concentration in BALF of patients with asthma. The finding that concentrations of this chemokine correlated with leukocyte numbers in BALF suggests that this chemokine may contribute to the cell recruitment in asthma.

An anti‐inflammatory oligopeptide produced by Entamoeba histolytica down‐regulates the expression of pro‐inflammatory chemokines

Axenically grown Entamoeba histolytica produces a pentapeptide (Met‐Gln‐Cys‐Asn‐Ser) with anti‐inflammatory properties that, among others, inhibits the in vitro and in vivo locomotion of human monocytes, sparing polymorphonuclear leucocytes from this effect [hence the name originally given: Monocyte Locomotion Inhibitory Factor (MLIF)]. A synthetic construct of this peptide displays the same effects as the native material. We now added MLIF to resting and PMA‐stimulated cells of a human monocyte cell line and measured the effect upon mRNA and protein expression of pro‐inflammatory chemokines (RANTES, IP‐10, MIP‐1α, MIP‐1β, MCP‐1, IL‐8, I‐309 and lymphotactin) and the shared CC receptor repertoire. The constitutive expression of these chemokines and the CC receptors was unaffected, whereas induced expression of MIP‐1α, MIP‐1β, and I‐309, and that of the CCR1 receptor – all involved in monocyte chemotaxis – was significantly inhibited by MLIF. This suggests that the inhibition of monocyte functions by MLIF may not only be exerted directly on these cells, but also – and perhaps foremost – through a conglomerate down‐regulation of endogenous pro‐inflammatory chemokines.

Chemokines and Their Receptors in the Allergic Airway Inflammatory Process

The development of the allergic airway disease conveys several cell types, such as T-cells, eosinophils, mast cells, and dendritic cells, which act in a special and temporal synchronization. Cellular mobilization and its complex interactions are coordinated by a broad range of bioactive mediators known as chemokines. These molecules are an increasing family of small proteins with common structural motifs and play an important role in the recruitment and cell activation of both leukocytes and resident cells at the allergic inflammatory site via their receptors. Trafficking and recruitment of cell populations with specific chemokines receptors assure the presence of reactive allergen-specific T-cells in the lung, and therefore the establishment of an allergic inflammatory process. Different approaches directed against chemokines receptors have been developed during the last decades with promising therapeutic results in the treatment of asthma. In this review we explore the role of the chemokines and chemokine receptors in allergy and asthma and discuss their potential as targets for therapy.

Immunization with a tetramer derivative of an anti‐inflammatory pentapeptide produced by Entamoeba histolytica protects gerbils (Meriones unguiculatus) against experimental amoebic abscess of the liver

Axenically grown Entamoeba histolytica produces a pentapeptide (Met‐Gln‐Cys‐Asn‐Ser) with several anti‐inflammatory properties, including the inhibition of human monocyte locomotion (Monocyte Locomotion Inhibitory Factor (MLIF)). A construct displays the same effects as the native material. It remains to be seen if MLIF is used, or even produced in vivo by the tissue‐invading parasite. If MLIF were to be relevant in invasive amoebiasis, immunizing against it could diminish this parasite advantage and prevent lesions. KLH‐linked MLIF mixed with Freunds adjuvant was too aggressive an immunizing material to answer this question. However, immunization with a tetramer of MLIF (but not a scrambled version of MLIF) around a lysine core (MLIF–MAPS), that displays increased antigenicity, yet lacks excessive innate immunity activation, completely protects gerbils against amoebic abscess of the liver caused by the intraportal injection of virulent E. histolytica. Liver abscesses caused by Listeria monocytogenes were not prevented. Invasive E. histolytica may produce the parent protein of MLIF in vivo, and if appropriately cleaved, it may play a role in invasive amoebiasis. MLIF may join new vaccination strategies against amoebiasis.

Cytokine expression in CD4+ cells exposed to the monocyte locomotion inhibitory factor produced by Entamoeba histolytica

Entamoeba histolytica produces monocyte locomotion inhibitory factor (MLIF), a pentapeptide with in vitro and in vivo anti-inflammatory properties. MLIF may interfere with leukocyte migration, disturbing the balance of pro- and anti-inflammatory cytokines secreted by CD4+ T lymphocytes. We evaluated the effect of MLIF on expression of pro- and anti-inflammatory cytokines in human CD4+ T lymphocytes. Regulatory cytokines [interleukin-1 beta (IL-1β), IL-2, interferon gamma (IFN-γ), IL-5, IL-6, and IL-10] were studied by enzyme-linked immunosorbent assay method in CD4+-cell supernatant fluids. Proinflammatory cytokines were produced per se by MLIF (IL-1β, IL-2, and IFN-γ) and also anti-inflammatory cytokines (IL-5, IL-6, and IL-10) with 1-phorbol-12 myristate-13 acetate + MLIF; the IL-1β, IFN-γ, IL-5 and IL-6 production was inhibited but not that of IL-10 which disclosed increase in its expression. MLIF disturbs the pro- and anti-inflammatory balance, and it induces inhibition of IL-1β (principal proinflammatory cytokine) and increases IL-10 (prototype of an anti-inflammatory cytokine).

Aspirin-intolerant asthma: a comprehensive review of biomarkers and pathophysiology.

Aspirin-exacerbated respiratory disease is a tetrad of nasal polyps, chronic hypertrophic eosinophilic sinusitis, asthma, and sensitivity to aspirin. Unawareness of this clinical condition by patients and physicians may have grave consequences because of its association with near-fatal asthma. The pathogenesis of aspirin-intolerant asthma is not related with an immunoglobin E mechanism, but with an abnormal metabolism of the lipoxygenase (LO) and cyclooxygenase (COX) pathways. At present, a diagnosis of aspirin sensitivity can be established only by provocative aspirin challenge, which represents a health risk for the patient. This circumstance has encouraged the search for aspirin intolerance-specific biomarkers. Major attempts have focused on mediators related with inflammation and eicosanoid regulation. The use of modern laboratory techniques including high-throughput methods has facilitated the detection of dozens of biological metabolites associated with aspirin-intolerant asthma disease. Not surprisingly, the majority of these is implicated in the LO and COX pathways. However, substantial amounts of data reveal the participation of many genes deriving from different ontologies. Biomarkers may represent a powerful, noninvasive tool in the diagnosis of aspirin sensitivity; moreover, they could provide a new way to classify asthma phenotypes.

An amebic anti-inflammatory peptide down-regulates ex vivo IL-1β expression in patients with rheumatoid arthritis

UNLABELLED The monocyte locomotion inhibitory factor (MLIF) is a heat-stable pentapeptide produced by Entamoeba histolytica in culture. This factor displays several anti-inflammatory properties (i.e., inhibition of locomotion and respiratory burst in monocytes, reduction of skin hypersensitivity and delay of mononuclear cells in human Rebuck skin windows) with inhibition of adhesion molecules, chemokines, and other genes including interleukin-1β (IL-1β). In animal models, it reduces carragenin-induced inflammation and delays the inflammatory process in murine collagen-induced arthritis (CIA). OBJECTIVES To test, in vitro, the anti-inflammatory capacity of MLIF on a promonocytic human cell line (U-937) cells and peripheral blood mononuclear cells (PBMC) from healthy subjects and from patients with rheumatoid arthritis (RA). MATERIAL AND METHODS IL-1β gene expression was evaluated in cell cultures either in the presence of MLIF, lipopolysaccharide (LPS), or both. Relative gene expression and immunoreactivity of IL-1β were assayed in cells and supernatants, respectively. RESULTS Amebic peptide was able to down-regulate LPS-induced expression of IL-1β, in U-937 cells without a detectable effect upon the bioavailability of the cytokine. In similar culture conditions, MLIF was capable to down-regulate baseline and LPS-induced expression of IL-β only in PBMC from patients with RA. Peptide effect on immunoreactivity of IL-1β was not statistically significant. CONCLUSIONS MLIF exerts, in primed cells, exquisite anti-inflammatory properties that deserve to be explored mechanistically.