Knockdown of double-stranded RNases (dsRNases) enhances oral RNA interference (RNAi) in the corn leafhopper, Dalbulus maidis.

The leafhopper Dalbulus maidis is a harmful pest that causes severe damage to corn crops. Conventional chemical pesticides have negative environmental impacts, emphasizing the need for alternative solutions. RNA interference (RNAi) is a more specific and environmentally friendly method for controlling pests and reducing the negative impacts of current pest management practices. Previous studies have shown that orally administered double-stranded RNA (dsRNA) is less effective than injection protocols in silencing genes. This study focuses on identifying and understanding the role of double-stranded ribonucleases (dsRNases) in limiting the efficiency of oral RNAi in D. maidis. Three dsRNases were identified and characterized, with Dmai-dsRNase-2 being highly expressed in the midgut and salivary glands. An ex vivo degradation assay revealed significant nuclease activity, resulting in high instability of dsRNA when exposed to tissue homogenates. Silencing Dmai-dsRNase-2 improved the insects' response to the dsRNA targeting the gene of interest, providing evidence of dsRNases involvement in oral RNAi efficiency. Therefore, administering both dsRNase-specific and target gene-specific-dsRNAs simultaneously is a promising approach to increase the efficiency of oral RNAi and should be considered in future control strategies.

Exploring the immunomodulatory role of virtual memory CD8+ T cells: Role of IFN gamma in tumor growth control.

Virtual memory CD8+ T cells (TVM) have been described as cells with a memory-like phenotype but without previous antigen (Ag) exposure. TVM cells have the ability to respond better to innate stimuli rather than by TCR engagement, producing large amounts of interferon gamma (IFNγ) after stimulation with interleukin (IL)-12 plus IL-18. As a result of the phenotypic similarity, TVM cells have been erroneously included in the central memory T cell subset for many years. However, they can now be discriminated via the CD49d receptor, which is up-regulated only on conventional memory T cells (TMEM) and effector T cells (TEFF) after specific cognate Ag recognition by a TCR. In this work we show that systemic expression of IL-12 plus IL-18 induced an alteration in the normal TVM vs TMEM/TEFF distribution in secondary lymphoid organs and a preferential enrichment of TVM cells in the melanoma (B16) and the pancreatic ductal adenocarcinoma (KPC) tumor models. Using our KPC bearing OT-I mouse model, we observed a significant increase in CD8+ T cell infiltrating the tumor islets after IL-12+IL-18 stimulation with a lower average speed when compared to those from control mice. This finding indicates a stronger interaction of T cells with tumor cells after cytokine stimulation. These results correlate with a significant reduction in tumor size in both tumor models in IL-12+IL-18-treated OT-I mice compared to control OT-I mice. Interestingly, the absence of IFNγ completely abolished the high antitumor capacity induced by IL-12+IL-18 expression, indicating an important role for these cytokines in early tumor growth control. Thus, our studies provide significant new information that indicates an important role of TVM cells in the immune response against cancer.

Baja incidencia de cardiopatía clínicamente significativa en niños en edad escolar tras padecer COVID-19 / The low incidence of clinically significant heart disease in school-age children following COVID-19

No es clara la carga de morbimortalidad de la lesión cardíaca clínicamente evidente secundaria a la enfermedad por coronavirus de 2019 (COVID-19) en los niños en edad escolar. A lo largo de 12 meses, en un importante hospital pediátrico académico en la región del medio oeste de Estados Unidos, hubo 1481 casos de COVID-19 sin hospitalización en niños en edad escolar por lo demás sanos, en quienes se hicieron 195 pruebas cardíacas. Si bien aparecieron hallazgos fortuitos, no se descubrió ninguna patología cardíaca relacionada con la COVID-19. Además, ~3 % de los niños solamente tuvieron síntomas cardíacos agudos que requirieron una evaluación por el área de cardiología pediátrica. Los niños que no fueron hospitalizados por COVID-19 tienen un riesgo muy bajo de desarrollar daño cardíaco clínicamente significativo y son más propensos a presentar hallazgos fortuitos.

The burden of clinically-apparent cardiac injury secondary to coronavirus disease 2019 (COVID-19) in school-age children is unclear. Over 12 months at a large academic pediatric hospital in the Midwestern portion of the United States, there were 1481 COVID-19 positive non-hospitalized otherwise healthy schoolaged children with 195 having cardiac testing performed. While incidental findings occurred, no definitive COVID-19 related cardiac pathology was discovered. Additionally, only ~3 % of children had acute cardiac symptoms necessitating evaluation by pediatric cardiology. School-age children who were not hospitalized for COVID-19 have a very low risk of having clinically significant cardiac damage and are more likely to discover incidental findings.

The low incidence of clinically significant heart disease in school-age children following COVID-19. / Baja incidencia de cardiopatía clínicamente significativa en niños en edad escolar tras padecer COVID-19.

The burden of clinically-apparent cardiac injury secondary to coronavirus disease 2019 (COVID-19) in school-age children is unclear. Over 12 months at a large academic pediatric hospital in the Midwestern portion of the United States, there were 1481 COVID-19 positive non-hospitalized otherwise healthy schoolaged children with 195 having cardiac testing performed. While incidental findings occurred, no definitive COVID-19 related cardiac pathology was discovered. Additionally, only ~3% of children had acute cardiac symptoms necessitating evaluation by pediatric cardiology. School-age children who were not hospitalized for COVID-19 have a very low risk of having clinically significant cardiac damage and are more likely to discover incidental findings.

No es clara la carga de morbimortalidad de la lesión cardíaca clínicamente evidente secundaria a la enfermedad por coronavirus de 2019 (COVID-19) en los niños en edad escolar. A lo largo de 12 meses, en un importante hospital pediátrico académico en la región del medio oeste de Estados Unidos, hubo 1481 casos de COVID-19 sin hospitalización en niños en edad escolar por lo demás sanos, en quienes se hicieron 195 pruebas cardíacas. Si bien aparecieron hallazgos fortuitos, no se descubrió ninguna patología cardíaca relacionada con la COVID-19. Además, ~3 % de los niños solamente tuvieron síntomas cardíacos agudos que requirieron una evaluación por el área de cardiología pediátrica. Los niños que no fueron hospitalizados por COVID-19 tienen un riesgo muy bajo de desarrollar daño cardíaco clínicamente significativo y son más propensos a presentar hallazgos fortuitos.

Immunological Memory to Zika Virus in a University Community in Colombia, South America.

Zika virus appeared in South America in 2015, generating alarm worldwide as it causes microcephaly and autoimmunity. This study aims to determine the serological footprint of the incoming epidemic in a student community and to characterize the memory functional cell response during post convalescence. In a cross-sectional study, Zika-specific IgG using LIA immunoassay was found in 328 university students (CI=95%), while in the second phase, the functional cellular memory response for IFN-γ and IL-2 was quantified using post-stimulus ELISpot with inactivated virus, starting with individuals seropositive for Zika and control individuals (seropositive only for Dengue and seronegative for Zika-Dengue). Depending on the antigen used, memory humoral response (IgG) against Zika Virus was observed in >60% of the population; seropositivity for NS1 was 21.1% higher than E antigen with high intensity. The analysis of cell functionality in 22 individuals seropositive for Zika virus revealed either IFN-γ+ or IL-2+ cells in 86.3% of cases (Th1 profile), presenting multifunctionality in 50% (11 individuals), 64% of which presented> 6 SFC/104 PBMCs (>600 SFC/106 PBMC), reflecting memory circulating cells. A good agreement (Kappa= 0.754) was observed between the coexistence of both cellular and humoral responses but not in their intensity.

Chk1 loss creates replication barriers that compromise cell survival independently of excess origin firing.

The effectiveness of checkpoint kinase 1 (Chk1) inhibitors at killing cancer cells is considered to be fully dependent on their effect on DNA replication initiation. Chk1 inhibition boosts origin firing, presumably limiting the availability of nucleotides and in turn provoking the slowdown and subsequent collapse of forks, thus decreasing cell viability. Here we show that slow fork progression in Chk1-inhibited cells is not an indirect effect of excess new origin firing. Instead, fork slowdown results from the accumulation of replication barriers, whose bypass is impeded by CDK-dependent phosphorylation of the specialized DNA polymerase eta (Polη). Also in contrast to the linear model, the accumulation of DNA damage in Chk1-deficient cells depends on origin density but is largely independent of fork speed. Notwithstanding this, origin dysregulation contributes only mildly to the poor proliferation rates of Chk1-depleted cells. Moreover, elimination of replication barriers by downregulation of helicase components, but not their bypass by Polη, improves cell survival. Our results thus shed light on the molecular basis of the sensitivity of tumors to Chk1 inhibition.

Diverse cyclic seed peptides in the Mexican zinnia (Zinnia haageana).

A new family of small plant peptides was recently described and found to be widespread throughout the Millereae and Heliantheae tribes of the sunflower family Asteraceae. These peptides originate from the post-translational processing of unusual seed-storage albumin genes, and have been termed PawS-derived peptides (PDPs). The prototypic family member is a 14-residue cyclic peptide with potent trypsin inhibitory activity named SunFlower Trypsin Inhibitor (SFTI-1). In this study we present the features of three new PDPs discovered in the seeds of the sunflower species Zinnia haageana by a combination of de novo transcriptomics and liquid chromatography-mass spectrometry. Two-dimensional solution NMR spectroscopy was used to elucidate their structural characteristics. All three Z. haageana peptides have well-defined folds with a head-to-tail cyclized peptide backbone and a single disulfide bond. Although two possess an anti-parallel ß-sheet structure, like SFTI-1, the Z. haageana peptide PDP-21 has a more irregular backbone structure. Despite structural similarities with SFTI-1, PDP-20 was not able to inhibit trypsin, thus the functional roles of these peptides is yet to be discovered. Defining the structural features of the small cyclic peptides found in the sunflower family will be useful for guiding the exploitation of these peptides as scaffolds for grafting and protein engineering applications.

The Langerhans islet cells of female rabbits are differentially affected by hypothyroidism depending on the islet size.

Effects of hypothyroidism on the glucose and insulin levels are controversial, and its impact on the Langerhans islet morphology of adult subjects has been poorly addressed. In spite of hypothyroidism and diabetes mellitus are more frequent in females than in males, most studies using animal models have been done in males. The effect of hypothyroidism on the immunolabeling of thyroid hormone receptors (TRs) and thyrotropin receptor (TSHR) of islet cells is unknown. The aim of this study was to determine the effect of hypothyroidism on the glucose and insulin concentrations, morphometry of islets, and immunostaining of TRs α1-2 and ß1 and TSHR of islet cells in female rabbits. Control and hypothyroid (0.02% of methimazole for 30 days) animals were used to quantify blood levels of glucose and insulin, density of islets, cross-sectional area (CSA) of islets, number of cells per islet, cell proliferation, and the immunolabeling of TRs α1-2, TRß1, and TSHR. Student's t or Mann-Whitney-U tests, two-way ANOVAs, and Fischer's tests were applied. Concentrations of glucose and insulin, as well as the insulin resistance were similar between groups. Hypothyroidism did not affect the density or the CSA of islets. The analysis of islets by size showed that hypothyroidism reduced the cell number in large and medium islets, but not in small ones. In small islets, cell proliferation was increased. The immunoreactivity of TRα1-2, TRß1, and TSHR was increased by hypothyroidism in all islet sizes. Our results show that hypothyroidism affects differentially the islet cells depending on the size of islets.

Sugared water consumption by adult offspring of mothers fed a protein-restricted diet during pregnancy results in increased offspring adiposity: the second hit effect.

Poor maternal nutrition predisposes offspring to metabolic disease. This predisposition is modified by various postnatal factors. We hypothesised that coupled to the initial effects of developmental programming due to a maternal low-protein diet, a second hit resulting from increased offspring postnatal sugar consumption would lead to additional changes in metabolism and adipose tissue function. The objective of the present study was to determine the effects of sugared water consumption (5% sucrose in the drinking-water) on adult offspring adiposity as a 'second hit' following exposure to maternal protein restriction during pregnancy. We studied four offspring groups: (1) offspring of mothers fed the control diet (C); (2) offspring of mothers fed the restricted protein diet (R); (3) offspring of control mothers that drank sugared water (C-S); (4) offspring of restricted mothers that drank sugared water (R-S). Maternal diet in pregnancy was considered the first factor and sugared water consumption as the second factor - the second hit. Body weight and total energy consumption, before and after sugared water consumption, were similar in all the groups. Sugared water consumption increased TAG, insulin and cholesterol concentrations in both the sexes of the C-S and R-S offspring. Sugared water consumption increased leptin concentrations in the R-S females and males but not in the R offspring. There was also an interaction between sugared water and maternal diet in males. Sugared water consumption increased adipocyte size and adiposity index in both females and males, but the interaction with maternal diet was observed only in females. Adiposity index and plasma leptin concentrations were positively correlated in both the sexes. The present study shows that a second hit during adulthood can amplify the effects of higher adiposity arising due to poor maternal pregnancy diet in an offspring sex dependent fashion.

Hernia de Richter como causa de fístula enterocutánea / Richter hernia as a cause of enterocutaneous fistula

Resumen: Paciente de sexo masculino de 51 años, sin comorbilidades. Consulta por secreción de aspecto fecaloide de15 días de evolución, que se exterioriza por fosa ilíaca derecha, región que se constata flogótica, con formaciónindurada redondeada en tejido celular subcutáneo. Antecedente de laparotomía mediana supra-infraumbilical por peritonitis apendicular hace 30 años, con cicatriz abdominal viciosa por retracciones y eventración. Por mala evolución y fístula cutánea de alto débito, se realiza laparotomía exploradora y resección de tejidocelulo-cutáneo con orificio fistuloso. Se halla por esta vía de abordaje en topografía de fosa ilíaca derecha, unsaco herniario de 5cm de diámetro con contenido graso, que al ser resecado permite observar pequeño bordeantimesentérico del íleon pellizcado por un anillo herniario rígido de 1,5 cm de diámetro, el cual se correspondería con el sitio de exteriorización de algún drenaje de su primer cirugía...

Summary: Richter’s Hernia, or partial enterocele, is the protrusion of the antimesenteric border of an intestinal loop through an orifice in the abdominal wall, congenital or acquired. 51 years old, male patient, without comorbilities, with fecaloid secretion that exteriorizes in right iliac fossa, 10 days of evolution. The patient refers a surgery of appendicular peritonitis 30 years ago.Physical examination, vicious, median supra-infra umbilical scar, with surgical wound eventration. After performing surgery an ileocutaneous fistula is noted, without finding the cause. Containing a preherniarylipoma After its resection a small antimesenteric border of the ileonis evidenced, pinched by aherniary ring with an approximate diameter of 1,5 cm, which would correspond to the drain exteriorizationorifice of his first surgery.

Re-visiting Trichuris trichiura intensity thresholds based on anemia during pregnancy.

BACKGROUND: The intensity categories, or thresholds, currently used for Trichuris trichiura (ie. epg intensities of 1-999 (light); 1,000-9,999 epg (moderate), and ≥ 10,000 epg (heavy)) were developed in the 1980s, when there were little epidemiological data available on dose-response relationships. This study was undertaken to determine a threshold for T. trichiura-associated anemia in pregnant women and to describe the implications of this threshold in terms of the need for primary prevention and chemotherapeutic interventions. METHODOLOGY/PRINCIPAL FINDINGS: In Iquitos, Peru, 935 pregnant women were tested for T. trichiura infection in their second trimester of pregnancy; were given daily iron supplements throughout their pregnancy; and had their blood hemoglobin levels measured in their third trimester of pregnancy. Women in the highest two T. trichiura intensity quintiles (601-1632 epg and ≥ 1633 epg) had significantly lower mean hemoglobin concentrations than the lowest quintile (0-24 epg). They also had a statistically significantly higher risk of anemia, with adjusted odds ratios of 1.67 (95% CI: 1.02, 2.62) and 1.73 (95% CI: 1.09, 2.74), respectively. CONCLUSIONS/SIGNIFICANCE: This analysis provides support for categorizing a T. trichiura infection ≥ 1,000 epg as 'moderate', as currently defined by the World Health Organization. Because this 'moderate' level of T. trichiura infection was found to be a significant risk factor for anemia in pregnant women, the intensity of Trichuris infection deemed to cause or aggravate anemia should no longer be restricted to the 'heavy' intensity category. It should now include both 'heavy' and 'moderate' intensities of Trichuris infection. Evidence-based deworming strategies targeting pregnant women or populations where anemia is of concern should be updated accordingly.

Diagnosis of Wuchereria bancrofti infection by the polymerase chain reaction using urine and day blood samples from amicrofilaraemic patients.

A sensitive and specific polymerase chain reaction (PCR) based on a highly repeated deoxyribonucleic acid (DNA) sequence (188 bp; SspI repeat) was tested for the detection of Wuchereria bancrofti DNA in blood and urine samples collected during the day from individuals in Coque, Recife, Brazil, an endemic area for W. bancrofti. All microfilaraemic individuals were also positive by PCR, irrespective of the samples used. The PCR system was capable of detecting W. bancrofti DNA in amicrofilaraemic individuals: c. 93% were positive by PCR when day blood samples were used and 59.7% when urine samples collected at 07:00 were used. Thus, nocturnally periodic W. bancrofti infection can be detected in blood samples collected during the day, which is convenient for large-scale screening. In addition, non-invasive urine collection provided suitable samples for PCR, which is clearly advantageous for preliminary mass diagnosis.

Characterization and toxicity to mosquito larvae of four Bacillus sphaericus strains isolated from Brazilian soils.

Four Bacillus sphaericus strains, S1, S2, S5, and L2, isolated from Brazilian soils, were found to be toxic to larvae of the mosquitoes Culex pipiens and Anopheles stephensi at a level similar to that of strain 2362 which is now used operationally. Like strain 2362, the four strains belonged to the serotype H5 and produced major proteins of apparent molecular weights of 125, 110, 56, and 43 kDa. These latter two proteins were immunologically related to toxins of the same molecular weight as B. sphaericus 2362. Although the four Brazilian strains were very similar to strain 2362, gas chromatography analysis of the fatty acids revealed that these strains were different from strain 2362 and from each other, except for a possible similarity between strains S1 and S5.