Preparation of Dipteran Larvae for Scanning Electron Microscopy with Special Reference to Myiasigen Dipteran Species

Although controversy exists concerning the role of chemical fixatives in scanning electron microscopy (SEM) studies of Dipteran larvae, we have observed that filtered 10% formaldehyde solution gives excellent results as a preservative. After immersing in vivo in formaldehyde, the larvae material is preserved for prolonged periods (up to 8 months), before examination with SEM. As a fixative, formaldehyde preserves the structure of the larval cuticle and produces no visible artifacts. Moreover, postfixation is not necessary. Due to pecularities of the way of life of Wohlfahrtia magnifica (principally the accumulations of necrotic tissue, purulent particles, and other types of substances that often adhere to the numerous spines of larvae), this species must be cleaned before examination by SEM. Manual cleaning with alternating bidistilled water and 0.9% saline solution proved to be a rapid, easy and inexpensive method that gave good results. Both lyophilization drying and critical point drying were used before sputtering the material. While lyophilization drying proved to be the most effective method for instars II and III, critical point drying was the best technique for study of specimens belonging to instar I. The optimum time for drying and conditions for lyophilization and sputter-coating with gold were determined experimentally. Samples were mounted on SEM stubs with double-sided adhesive and silver conductive paint. The method proposed is easy and effective for the SEM study of larvae myiasis-producing diptera

A dynamic explanation for the origin of the western Mediterranean organic-rich layers

The eastern Mediterranean sapropels are among the most intensively investigated phenomena in the paleoceanographic record, but relatively little has been written regarding the origin of the equivalent of the sapropels in the western Mediterranean, the organic-rich layers (ORLs). ORLs are recognized as sediment layers containing enhanced total organic carbon that extend throughout the deep basins of the western Mediterranean and are associated with enhanced total barium concentration and a reduced diversity (dysoxic but not anoxic) benthic foraminiferal assemblage. Consequently, it has been suggested that ORLs represent periods of enhanced productivity coupled with reduced deep ventilation, presumably related to increased continental runoff, in close analogy to the sapropels. We demonstrate that despite their superficial similarity, the timing of the deposition of the most recent ORL in the Alboran Sea is different than that of the approximately coincident sapropel, indicating that there are important differences between their modes of formation. We go on to demonstrate, through physical arguments, that a likely explanation for the origin of the Alboran ORLs lies in the response of the western Mediterranean basin to a strong reduction in surface water density and a shoaling of the interface between intermediate and deep water during the deglacial period. Furthermore, we provide evidence that deep convection had already slowed by the time of Heinrich Event 1 and explore this event as a potential agent for preconditioning deep convection collapse. Important differences between Heinrich-like and deglacial-like influences are highlighted, giving new insights into the response of the western Mediterranean system to external forcing

Tranexamic acid attenuates inflammatory response in cardiopulmonary bypass surgery through blockade of fibrinolysis: a case control study followed by a randomized double-blind controlled trial

INTRODUCTION: Extracorporeal circulation induces hemostatic alterations that lead to inflammatory response (IR) and postoperative bleeding. Tranexamic acid (TA) reduces fibrinolysis and blood loss after cardiopulmonary bypass (CPB). However, its effects on IR and vasoplegic shock (VS) are not well known and elucidating these effects was the main objective of this study. METHODS: A case control study was carried out to determine factors associated with IR after CPB. Patients undergoing elective CPB surgery were randomly assigned to receive 2 g of TA or placebo (0.9% saline) before and after intervention. We performed an intention-to-treat analysis, comparing the incidence of IR and VS. We also analyzed several biological parameters related to inflammation, coagulation, and fibrinolysis systems. We used SPSS version 12.2 for statistical purposes. RESULTS: In the case control study, 165 patients were studied, 20.6% fulfilled IR criteria, and the use of TA proved to be an independent protective variable (odds ratio 0.38, 95% confidence interval 0.18 to 0.81; P < 0.01). The clinical trial was interrupted. Fifty patients were randomly assigned to receive TA (24) or placebo (26). Incidence of IR was 17% in the TA group versus 42% in the placebo group (P = 0.047). In the TA group, we observed a significant reduction in the incidence of VS (P = 0.003), the use of norepinephrine (P = 0.029), and time on mechanical ventilation (P = 0.018). These patients showed significantly lower D-dimer, plasminogen activator inhibitor 1, and creatine-kinase levels and a trend toward lower levels of soluble tumor necrosis factor receptor and interleukin-6 within the first 24 hours after CPB. CONCLUSION: The use of TA attenuates the development of IR and VS after CPB. TRIAL REGISTRATION NUMBER: ISRCTN05718824

TREM1 regulates antifungal immune responses in invasive pulmonary aspergillosis.

Pattern recognition receptors (PRRs) are responsible for Aspergillus fumigatus recognition by innate immunity and its subsequent immune signaling. The triggering receptor expressed on myeloid cells 1 (TREM1) is a recently characterized pro-inflammatory receptor constitutively expressed on the surface of neutrophils and macrophages. A soluble form (sTREM1) of this protein that can be detected in human body fluids has been identified. Here we investigated the role of TREM1 during invasive pulmonary aspergillosis (IPA). IPA patients displayed significantly higher levels of sTREM1 in bronchoalveolar lavages when compared to control patients. Functional analysis in TREM1 showed that the levels of sTREM1 and TREM1 pathway-related cytokines were influenced by single nucleotide polymorphisms in TREM1. In addition, we confirmed a role of TREM1 on antifungal host defense against A. fumigatus in a murine model of IPA. TREM1 deficiency increased susceptibility to infection in the immunosuppressed murine host. Deletion of TREM1 showed delayed innate and adaptive immune responses and impaired pro-inflammatory cytokine responses. The absence of TREM1 in primary macrophages attenuated the TLR signaling by altering the expression of both receptor and effector proteins that are critical to the response against A. fumigatus. In this study, and for the first time, we demonstrate the key role for the TREM1 receptor pathway during IPA.This work was supported by the Fundação para a Ciência e a Tecnologia [PTDC/SAU-SER/29635/2017]; Fundação para a Ciência e a Tecnologia [UIDB/50026/2020 and UIDP/50026/2020]; Fundação para a Ciência e a Tecnologia [PTDC/MED-GEN/28778/2017]; H2020 Excellent Science [NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023)]; Instituto de Salud Carlos III [RD16/CIII/0004/0003]; Instituto de Salud Carlos III [PI18CIII/00045]; Instituto de Salud Carlos III [MPY 1277/15]; Ministerio de Ciencia, Innovación y Universidades [RTI2018-099114-B-I00]; Associação Viver a Ciência (PT) [SFRH/BD/136814/2018]; “la Caixa” Foundation [ID 100010434].S

Visceral fat area and cardiometabolic risk: The Kardiovize study

BACKGROUND: Visceral fat is associated with adiposity-based complications. Bioimpedance measurement allows estimation of visceral fat area (VFA) in an easy manner. However, a validated cut-off value for VFA by bioimpedance associated with cardiometabolic risk is lacking in European population. AIM: To determine cut-off values of VFA measured via bioimpedance associated with cardiometabolic risk. METHODS: Random cross-sectional Czech population-based sample of 25-64 years old subjects. Receiver Operating Characteristic (ROC) curves were used and the area under the curve (AUC), sensitivity, and specificity were calculated. The Cardiometabolic Disease Staging System (CMDS) was used to classify cardiometabolic risk: Stage 1 - 1 or 2 metabolic syndrome (MetS) components, without impaired fasting glucose (IFG); Stage 2 - MetS or IFG; Stage 3 - MetS with IFG; Stage 4 - type 2 diabetes and/or cardiovascular disease. RESULTS: 2052 participants (54.5% females, median age 49 years) were included. Median VFA (inter-quartile range) were 82.2 cm2 (54.8) in men and 89.8 cm2 (55.6) in women. The best VFA cut-offs associated with Stage 1 in men and women were 71 cm2 (sensitivity = 0.654; specificity = 0.427) and 83 cm2 (sensitivity = 0.705; specificity = 0.556) ; Stage 2: 84 cm2 (sensitivity = 0.673; specificity = 0.551) and 98 cm2 (sensitivity = 0.702; specificity = 0.628) ; Stage 3: 90 cm2 (sensitivity = 0.886; specificity = 0.605) and 109 cm2 (sensitivity = 0.755; specificity = 0.704); Stage 4: 91 cm2 (sensitivity = 0.625; specificity = 0.611) and 81 cm2 (sensitivity = 0.695; specificity = 0.448), respectively. CONCLUSION: A cut-off value of VFA of 71 cm2 in men and 83 cm2 in women exhibited the earliest stage of cardiometabolic risk, and 90 cm2 in men and 109 cm2 in women showed the best performance to detect risk

Earthworm management in tropical agroecosystems

Ecological and demographic parameters of 26 species of native and exotic earthworms species common in tropical agroecosystems, with large environmental tolerance and/or extended distribution were investigated. Principal component analysis (PCA) isolated four groups : (i) large native endogeic and anecic species (16-32 g individual fresh wt) with long generation time (2-4 years), low fecundity (0.5-3.1 cocoons/year/adult) and one hatchling per cocoon ; (ii) medium size species (1.2-6 g) endogeic mesohumic, with intermediate fecundity (1.3-45 cocoons/year/adult) ; (iii) small species (0.17-1.25 g f.w.) mainly endogeic polyhumic, with short generation time (3-7 months), intermediate fecundity (10-68 cocoons/year/adult) and one hatchling per cocoon ; and (iv) generally small (80-150 mg f.w.) species mainly exotic and epigeic, with short generation time (1-3 months), very high fecundity (50-350 cocoons/year/adult) and up to three hatchlings per cocoon. Casts may be either large globular or small granular. The selective investigations of large organic particles and small mineral particles (clays) concentrates total organic matter in the casts. There is an intense mineralization rate of nitrogen in the casts (6-29% of organic N), exotic worms seeming to be less efficient than natives at mineralizing N. The mineral phosphorus content of casts is always at least 30% higher than in the non-ingested soil. All these worms ingest daily, on average, three times their own weight of soil at the adult stage (1-9) and much more when juvenile ; up to 1000 Mg dry soil/ha may transit yearly through earthworm guts. (Résumé d'auteur