Cytochemical study of Rhodnius neglectus and Rhodnius prolixus salivary gland cells (Hemiptera, Triatominae)

Triatomines are hematophagous bugs of medical interest in South and Central America, where they may act as invertebrate hosts of the hemoflagellate protozoa Trypanosoma cruzi (the causative of Chagas’ disease) and Trypanosoma rangeli (Tejera, 1920). Triatomines of Rhodnius genus have salivary gland formed by two close and independent units: the principal and the accessory. This gland secretes saliva that abounds in substances that facilitate and permit feeding. Despite this importance, there are few reports on its cytochemistry. In purpose of amplifying this understanding, in this work it was investigated the nuclear structures (chromatin and nucleolar corpuscles) of salivary gland cells of Rhodnius neglectus (Lent, 1954) and Rhodnius prolixus (Stål, 1859). The salivary glands were removed from adult insects, fixed and submitted to different cytochemical methods: lacto-acetic orcein, silver ion impregnation, Feulgen reaction, Toluidine Blue, Variant method of critical electrolyte concentration and C-banding. The results evidenced predominance of binucleated cells, with bulky and polyploid nucleus, decondensed chromatin and a large nucleolar area. In addition, cytoplasmic metachromasy and a clear association between nucleolar and heterochromatic corpuscles were observed. Such characteristics were associated with intense synthesis activity to produce saliva. Besides, the heterochromatic corpuscles observed with C Banding permitted the differentiation of sexes and species.

Silver Thrust

Combined media on photographic paper. 87" x 40"

Dark Clouds or Silver Linings? Knightian Uncertainty and Climate Change

This paper examines the impact of Knightian uncertainty upon optimal climate policy through the prism of a continuous-time real option modelling framework. We analytically determine optimal intertemporal climate policies under ambiguous assessments of climate damages. Additionally, numerical simulations are provided to illustrate the properties of the model. The results indicate that increasing Knightian uncertainty accelerates climate policy, i.e. policy makers become more reluctant to postpone the timing of climate policies into the future.

An improved silver staining procedure for schizodeme analysis in polyacrylamide gradient gels

A simple protocol is described for the silver staining of polyacrylamide gradient gels used for the separation of restriction fragments of kinetoplast DNA [schizodeme analysis of trypanosomatids (Morel et al., 1980)]. The method overcomes the problems of non-uniform staining and strong background color which are frequently encountered when conventional protocols for silver staining of linear gels. The method described has proven to be of general applicability for DNA, RNA and protein separations in gradient gels.

Cell surface expression of a functional rubella virus E1 glycoprotein by addition of a GPI anchor.

Rubella virus (RV) envelope glycoproteins E1 and E2 are targeted to the Golgi as heterodimers. While E2 contains a transmembrane Golgi retention signal, E1 is arrested in a pre-Golgi compartment in the absence of E2, and appears to require heterodimerization in order to reach the Golgi. Various forms of E1 with deletions in the ectodomain or lacking the cytoplasmic (CT) and transmembrane (TM) domains, as well as the 29 C-terminal amino acid residues of the ectodomain were also retained intracellularly. We therefore investigated the possibility of targetting E1 to the plasma membrane by addition of a glycosylphosphatidylinositol (GPI) anchor. We found that E1GPI was transported to the cell surface where it retained the hemadsorption activity characteristic of the wild-type E1/E2 heterodimer. Furthermore, coexpression of a mammalian GPI-specific phospholipase D (GPI-PLD) resulted in the release of E1GPI and in constitutive expression of a soluble form of E1. This study thus demonstrates that the GPI anchor has a dominant effect over the E1 pre-Golgi retention signal and that E1 is sufficient for hemadsorption.

In-situ revascularisation for secondary aorto-enteric fistulae: the success of silver-coated Dacron is closely linked to a suitable bowel repair.

OBJECTIVES: The purpose of this study was to assess short- and mid-term results of in-situ revascularisation (ISR) using silver-coated Dacron prostheses and bowel repair for management of secondary aorto-enteric fistulae (SAEF). DESIGN: Single-centre retrospective chart review. MATERIAL AND METHODS: This study includes all the patients treated by ISR using silver-coated Dacron for SAEF between 2006 and 2010. Primary end points were mortality and survival rates. Secondary end points were reinfection-free survival and secondary patency rates. RESULTS: Eighteen male patients with SAEF with a median age of 64 years were operated by ISR using silver-coated Dacron during the study period without operative death. The 30-day mortality was 22% and the in-hospital mortality rate was 39%. Indeed, during hospitalisation, a duodenal leak was observed in four patients including three who died. Four others patients died due to multi-system organ failure. Median follow-up was 16 months (range 1-66). The survival rate at 12 months was 55%. One duodenal leak was observed leading to death. The reinfection-free survival and the secondary patency rates at 12 months were 60% and 89%, respectively. CONCLUSION: In-situ revascularisation with silver-coated Dacron provides acceptable results in terms of mortality. This treatment may be useful for simple vascular reconstruction and allow greater attention to bowel repair that is a determinant in short- and mid-term survival.

Wet chemical silver treatment of endotracheal tubes to produce antibacterial surfaces.

Mechanically ventilated patients in hospitals are subjected to an increased risk of acquiring nosocomial pneumonia that sometimes has a lethal outcome. One way to minimize the risk could be to make the surfaces on endotracheal tubes antibacterial. In this study, bacterial growth was inhibited or completely prevented by silver ions wet chemically and deposited onto the tube surface. Through the wet chemical treatment developed here, a surface precipitate was formed containing silver chloride and a silver stearate salt. The identity and morphology of the surface precipitate was studied using x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and x-ray powder diffraction. Leaching of silver ions into solution was examined, and bacterial growth on the treated surfaces was assayed using Pseudomonas aeruginosa wild type (PAO1) bacteria. Furthermore, the minimum inhibitory concentration of silver ions was determined in liquid- and solid-rich growth medium as 23 and 18 microM, respectively, for P. aeruginosa.

A soluble hexameric form of CD40 ligand activates human dendritic cells and augments memory T cell response.

A strategy to improve the immunogenicity of candidate vaccines is to trigger the innate immune system. Triggering of CD40 at the surface of dendritic cells (DC) is essential in the induction of an efficient immune response. Although CD40 agonist antibodies have been shown to be potent inducers of immune responses in experimental models, serious safety concerns have been raised for their use in humans. In addition, the production of soluble functional CD40 ligand has been challenging and the soluble form existing so far is not developed anymore. Here, we have evaluated the potency of a new soluble form of hexameric CD40 ligand (sCD40L) to serve as an adjuvant for anti-viral T cell responses. sCD40L was able to activate human DC and to enhance virus-specific memory T cell responses. These results demonstrate that this soluble form of CD40 ligand may serve as an adjuvant for T cell response and thus provide the rationale for its potential use in T cell based vaccine strategies.

Addition of inspiratory resistance increases the amplitude of the slow component of O2 uptake kinetics.

The contribution of respiratory muscle work to the development of the O(2) consumption (Vo(2)) slow component is a point of controversy because it has been shown that the increased ventilation in hypoxia is not associated with a concomitant increase in Vo(2) slow component. The first purpose of this study was thus to test the hypothesis of a direct relationship between respiratory muscle work and Vo(2) slow component by manipulating inspiratory resistance. Because the conditions for a Vo(2) slow component specific to respiratory muscle can be reached during intense exercise, the second purpose was to determine whether respiratory muscles behave like limb muscles during heavy exercise. Ten trained subjects performed two 8-min constant-load heavy cycling exercises with and without a threshold valve in random order. Vo(2) was measured breath by breath by using a fast gas exchange analyzer, and the Vo(2) response was modeled after removal of the cardiodynamic phase by using two monoexponential functions. As anticipated, when total work was slightly increased with loaded inspiratory resistance, slight increases in base Vo(2), the primary phase amplitude, and peak Vo(2) were noted (14.2%, P < 0.01; 3.5%, P > 0.05; and 8.3%, P < 0.01, respectively). The bootstrap method revealed small coefficients of variation for the model parameter, including the slow-component amplitude and delay (15 and 19%, respectively), indicating an accurate determination for this critical parameter. The amplitude of the Vo(2) slow component displayed a 27% increase from 8.1 +/- 3.6 to 10.3 +/- 3.4 ml. min(-1). kg(-1) (P < 0.01) with the addition of inspiratory resistance. Taken together, this increase and the lack of any differences in minute volume and ventilatory parameters between the two experimental conditions suggest the occurrence of a Vo(2) slow component specific to the respiratory muscles in loaded condition.

IVA in addition to BMD can change the osteoporosis management in 25% of clinical routine patients

Introduction: Vertebral fracture is one of the major osteoporotic fractures which are unfortunately very often undetected. In addition, it is well known that prevalent vertebral fracture increases dramatically the risk of future additional fracture. Instant Vertebral Assessment (IVA) has been introduced in DXA device couple years ago to ease the detection of such fracture when routine DXA are performed. To correctly use such tool, ISCD provided clinical recommendation on when and how to use it. The aim of our study was to evaluate the ISCD guidelines in clinical routine patients and see how often it may change of patient management. Methods: During two months (March and April 2010), a medical questionnaire was systematically given to our clinical routine patient to check the validity of ISCD IVA recommendations in our population. In addition, all women had BMD measurement at AP spine, Femur and 1/3 radius using a Discovery A System (Hologic, Waltham, USA). When appropriate, IVA measurement had been performed on the same DXA system and had been centrally evaluated by two trained Doctors for fracture status according to the semi-quantitative method of Genant. The reading had been performed when possible between L5 and T4. Results: Out of 210 women seen in the consultation, 109 (52%) of them (mean age 68.2 ± 11.5 years) fulfilled the necessary criteria to have an IVA measurement. Out of these 109 women, 43 (incidence 39.4%) had osteoporosis at one of the three skeletal sites and 31 (incidence 28.4%) had at least one vertebral fracture. 14.7% of women had both osteoporosis and at least one vertebral fracture classifying them as "severe osteoporosis" while 46.8% did not have osteoporosis nor vertebral fracture. 24.8% of the women had osteoporosis but no vertebral fracture while 13.8% of women did have osteoporosis and vertebral fracture (clinical osteoporosis). Conclusion: In conclusion, in 52% of our patients, IVA was needed according to ISCD criteria. In half of them the IVA test influenced of patient management either by changing the type of treatment of simply by classifying patient as "clinical osteoporosis". IVA appears to be an important tool in clinical routine but unfortunately is not yet very often used in most of the centers.

Anticoagulant activity in salivary gland homogenates of Thyrsopelma guianense (Diptera: Simuliidae), the primary vector of onchocerciasis in the Brazilian Amazon

In this study, anticoagulant activity was detected in salivary gland homogenates (SGHs) of Thyrsopelma guianense (Diptera: Simuliidae). The SGH yielded 1.07 μg ± 0.03 (n = 15) of total soluble protein per pair of glands. In addition, following SDS-PAGE (12.5% gel) and silver nitrate staining, 12 polypeptides with molecular weights ranging from 14-69 kDa were detected in all physiological ages analyzed (12 h, 24 h, 48 h and 72 h following emergence). Coagulation bioassays showed that the SGHs had activities that interacted at all levels of coagulation (the intrinsic, extrinsic and common pathways), by extending the plasma recalcification time, prothrombin time, thrombin time. This is the first report on the activity of salivary gland proteins from the main vector of onchocerciasis in Brazil. We also suggest detailed studies on the morphology and function of the salivary glands in order to understand the role of these proteins in host/vector interactions.

IVA in addition to BMD can change the osteoporosis management in 25% of clinical routine patients.

Vertebral fracture is one of the major osteoporotic fractures which are unfortunately very often undetected. In addition, it is well known that prevalent vertebral fracture increases dramatically the risk of future additional fracture. Instant Vertebral Assessment (IVA) has been introduced in DXA device couple years ago to ease the detection of such fracture when routine DXA are performed. To correctly use such tool, ISCD provided clinical recommendation on when and how to use it. The aim of our study was to evaluate the ISCD guidelines in clinical routine patients and see how often it may change of patient management. During two months (March and April 2010), a medical questionnaire was systematically given to our clinical routine patient to check the validity of ISCD IVA recommendations in our population. In addition, all women had BMD measurement at AP spine, Femur and 1/3 radius using a Discovery A System (Hologic, Waltham, USA). When appropriate, IVA measurement had been performed on the same DXA system and had been centrally evaluated by two trained Doctors for fracture status according to the semi-quantitative method of Genant. The reading had been performed when possible between L5 and T4. Out of 210 women seen in the consultation, 109 (52%) of them (mean age 68.2±11.5 years) fulfilled the necessary criteria to have an IVA measurement. Out of these 109 women, 43 (incidence 39.4%) had osteoporosis at one of the three skeletal sites and 31 (incidence 28.4%) had at least one vertebral fracture. 14.7% of women had both osteoporosis and at least one vertebral fracture classifying them as "severe osteoporosis" while 46.8% did not have osteoporosis not vertebral fracture. 24.8% of the women had osteoporosis but no vertebral fracture while 13.8% of women did have osteoporosis but vertebral fracture (Clinical osteoporosis). In conclusion, in 52% of our patients, IVA was needed according to ISCD criteria. In half of them the IVA test influenced of patient management either my changing the type of treatment of simply by classifying patient as "clinical osteoporosis". IVA appears to be an important tool in clinical routine but unfortunately is not yet very often use in most of the centers.