Impact of dengue virus (serotype DENV-2) infection on liver of BALB/c mice: A histopathological analysis

In this research, we characterized the histopathological impact of dengue virus (serotype DENV-2) infection in livers of BALB/c mice. The mice were infected with different doses of DENV-2 via intraperitoneal injection and liver tissues were processed for histological analyses and variation was documented. In the BALB/c mouse model, typical liver tissues showed regular hepatocyte architecture, with normal endothelial cells surrounding sinusoid capillary. Based on histopathological observations, the liver sections of BALB/c mice infected by DENV-2 exhibited a loss of cell integrity, with a widening of the sinusoidal spaces. There were marked increases in the infiltration of mononuclear cells. The areas of hemorrhage and micro- and macrovesicular steatosis were noted. Necrosis and apoptosis were abundantly present. The hallmark of viral infection, i.e., cytopathic effects, included intracellular edema and vacuole formation, cumulatively led to sinusoidal and lobular collapse in the liver. The histopathological studies on autopsy specimens of fatal human DENV cases are important to shed light on tissue damage for preventive and treatment modalities, in order to manage future DENV infections. In this framework, the method present here on BALB/c mouse model may be used to study not only the effects of infections by other DENV serotypes, but also to investigate the effects of novel drugs, such as recently developed nano-formulations, and the relative recovery ability with intact immune functions of host.     

Pharmacokinetic evaluation of daclatasvir and ledipasvir in healthy volunteers using a validated highly sensitive spectrofluorimetric method

A simple, highly sensitive and selective spectrofluorimetric method has been developed and fully validated for the determination of daclatasvir (DAC) and ledipasvir (LED) in tablets and human plasma. The method is based on measurement of the native fluorescence in methanol at λ_em 384 nm after excitation at λ_ex 318 nm for DAC and in acetonitrile at λ_em 402 nm after excitation at λ_ex 340 nm for LED. The fluorescence intensity (FI) concentration plot was rectilinear over the ranges 1.2–12, 0.1–18 ng ml^?1 and 9–90, 1–100 ng ml^?1 with a good correlation of r = 0.9994 to r = 0.9997 in standard solution and human plasma for DAC and LED, respectively. The extraction of analytes from plasma was performed using methanol and acetonitrile as a precipitating agent with lower limit of quantification (LLOQ) of 0.1 and 1.0 ng ml^?1 for DAC and LED; respectively. The proposed method was validated according to the US Food and Drug Administration (FDA) guidelines and successfully applied for estimating the pharmacokinetic parameters of DAC and LED following oral administrations of their tablets.     

The Notch ligand Jagged-1 is able to induce maturation of monocyte-derived human dendritic cells

Notch receptors play a key role in several cellular processes including differentiation, proliferation, and apoptosis. This study investigated whether the activation of Notch signaling would affect the maturation of dendritic cells (DCs). Direct stimulation of Notch signaling in DCs with a peptide ligand induced DC maturation, similar to LPS: DCs up-regulated maturation markers, produced IL-12, lost endocytosis capacity, and became able to activate allogeneic T cells. Furthermore, coculture of DCs with cells expressing Notch ligand Jagged-1 induced up-regulation of maturation markers, IL-12 production, T cell proliferative responses, and IFN-gamma production. Our data suggest that activation of Notch by Jagged-1 plays an important role in maturation of human DCs. Additionally, they reveal a novel role for Notch signaling in cell maturation events distal to the cell fate decision fork. These data may have important medical implications, since they provide new reagents to induce DC activity, which may be beneficial as adjuvants in situations where an immune response needs to be elicited, such as tumor immunotherapy.     

Oxidative stress and thyroid impairment after gibberellic acid treatment in pregnant and lactating rats and their offspring

Gibberellic acid (GA?) has been worldwide used in agriculture as a plant growth regulator. The purpose of this study is to assess the effects of GA? on the morphology and the thyroid hormone levels in adult rats and their suckling pups. Animals were given daily 200 ppm GA? in drinking water from the 14th day of pregnancy until day 14 after delivery. Compared with a control group, GA?-treated mothers and pups showed an increase in body and thyroid weights, a decrease in plasma FT? and FT? levels, which were more pronounced in pups than in their mothers. Thyroid iodine content was also decreased in pups. These biochemical modifications corresponded histologically; the majority of follicles had cubical epithelial cells, which surrounded empty vesicular cavities. Toxicity was objectified by a significant increase in plasma malondialdehyde, protein carbonyls, and advanced oxidation protein products levels in GA?-treated dams and their suckling pups; while, the activities of superoxide dismutase, catalase, and glutathione peroxidase were decreased in plasma of both dams and their pups. Moreover, a significant decline was observed in plasma glutathione, nonprotein thiols, and vitamin C levels. We conclude that GA? treatment affects thyroid function and plasma antioxidant status in adult rats and their progeny.     

Toxicological impact of butralin,glyphosate-isopropylammonium and pendimethalin herbicides on physiological parameters of Biomphalaria alexandrina snails

ABSTRACT

Biomphalaria alexandrina snails have been used as bioindicators for freshwater qaulity and the effects of some herbicides such as butralin, glyphosate-isopropylammonium and pendimethalin). In the present study the effect of these three herbicides on snail biochemistry was examined. The results indicated that the herbicides increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the haemolymph of B. alexandrina snails and significantly decreased total protein and albumin content. Light microscopical examinations of haemocytes monolayers of B. alexandrina snails showed three different cell types (small cells, granulocytes and hyalinocytes). All three herbicides caused abnormalities in cell shapes. Flow cytometric analysis of haemocytes from B. alexandrina demonstrated that circulating haemocyte populations could be divided into two main subtypes differing in their granularity (granulocytes or hyalinocytes) and size (large and small cells). In addition, the flow cytometric analysis showed that the total number of dead haemocytes in the haemolymph was significantly increased in treated groups compared to the control group. Phagocytosis in groups treated with the herbicides was highly significantly increased compared to the control indicating a very strong response of the treated snails. The results of the alkaline comet assay of DNA damage demonstrated that these herbicides have a genotoxic effect.     

Phytochemical potential of Daphne gnidium in inhibiting growth of melanoma cells and enhancing melanogenesis of B16-F0 melanoma

In this study, we have investigated inhibitory capacity of ethyl acetate, total oligomer flavonoid (TOF), aqueous extracts and beta amyrin acetate, a triterpene isolated from ethyl acetate extract obtained from leaves of Daphne gnidium, on mouse melanoma (B16-F0 and B16-F10 cells) proliferation. Influence of these products on percentage cell distribution in cycle phases and melanogenesis was also studied. Cell viability was determined using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and flow cytometry was used to analyse effects of tested compounds on progression through the cell cycle. In addition, amounts of melanin and tyrosinase were measured spectrophotometrically at 475 nm. Ethyl acetate, TOF and aqueous extracts exhibited significant anti-proliferative activity after incubation with the two types of tumour skin cells B16-F0 and B16-F10. Furthermore, cell cycle analysis revealed that cells treated with ethyl acetate and TOF extracts were arrested predominantly in G2-M phase. Ethyl acetate extract has also the ability to enhance melanogenesis and tyrosinase activity of B16-F0 melanoma cells. Copyright © 2012 John Wiley & Sons, Ltd.     

Reciprocal Regulation of Endocytosis and Metabolism

The cellular uptake of many nutrients and micronutrients governs both their cellular availability and their systemic homeostasis. The cellular rate of nutrient or ion uptake (e.g., glucose, Fe³⁺, K⁺) or efflux (e.g., Na⁺) is governed by a complement of membrane transporters and receptors that show dynamic localization at both the plasma membrane and defined intracellular membrane compartments. Regulation of the rate and mechanism of endocytosis controls the amounts of these proteins on the cell surface, which in many cases determines nutrient uptake or secretion. Moreover, the metabolic action of diverse hormones is initiated upon binding to surface receptors that then undergo regulated endocytosis and show distinct signaling patterns once internalized. Here, we examine how the endocytosis of nutrient transporters and carriers as well as signaling receptors governs cellular metabolism and thereby systemic (whole-body) metabolite homeostasis.Interactions between the cell and its environment obligatorily involve events at the plasma membrane. Cell-surface proteins mediate nutrient uptake, product release, and the sensing of environmental changes, including signals from other cells. Appropriate sensing and response to extracellular cues is essential for the individual cell’s survival and for the coordinated cellular behavior in multicellular organisms. Accordingly, maintenance and dynamics of membrane proteins are fundamental mechanisms of cellular homeostasis and survival.Most plasma membrane proteins are in defined equilibria with intracellular endosomal compartments, such that the amount of a given protein at the plasma membrane is determined by the balance of its endocytosis and its recycling back to the cell surface from endosomes and other intracellular compartments (Fig. 1). Changes in the kinetics of membrane protein traffic acutely affect the levels of individual proteins at the cell surface and thereby impact how cells intake nutrients, sense the environment, and respond to external cues.Open in a separate windowFigure 1.Dynamic regulation of the cell-surface content of membrane proteins. Integral membrane proteins found at the cell surface are dynamically localized to the plasma membrane. The amount of any of these proteins at the cell surface is the result of the balance of exocytosis or recycling of vesicles containing that protein from intracellular membrane compartments and the endocytosis of the protein from the cell surface. Regulation of either the rate of exocytosis or endocytosis results in alteration of the cell-surface content of a given protein.Selective molecular mechanisms trigger traffic of plasma membrane proteins through endomembranes. Among them, ubiquitination and phosphorylation stand out as they can directly target the cargo proteins. Ubiquitination is the covalent attachment of the 76-amino acid polypeptide ubiquitin to the ε-amino group of specific lysine residues (reviewed by Miranda and Sorkin 2007; and see also Piper et al. 2014). Ubiquitination of cell-surface proteins is the principal mechanism of control of endocytosis in yeast (MacGurn et al. 2012), whereas in mammals, additional molecular mechanisms regulate the endocytosis of cell-surface proteins, including alterations in conformation that impact interaction with other proteins, and as mentioned, phosphorylation. Each of these modifications can either enhance or reduce the rates internalization, recycling, or degradation of specific proteins, highlighting the complexity of the regulation of endomembrane traffic. The intricate mechanisms that underlie the reciprocal regulation of endocytosis and metabolism are beginning to be understood. Here we discuss the endocytosis mechanisms in the regulation of cellular intake or efflux of iron, cholesterol, Na⁺, and glucose, and in the regulation of receptor signaling relevant to metabolism.     

Association Between Haptoglobin 2-2 Genotype and Coronary Artery Disease and Its Severity in a Tunisian Population

Haptoglobin (Hp) polymorphism generates three common human genotypes (Hp1-1, Hp2-1, and Hp2-2), having functional differences, related to the risk of development of cardiovascular diseases. These functions are a consequence of hemoglobin binding that leads to the synthesis of an antioxidant like ferritin. We explored the association of Hp polymorphism with significant coronary stenosis (SCS) and its severity within 400 Tunisian patients, using genotyping, biochemical parameters, and the Gensini score. After adjustments for age and gender, Hp2-2 was associated with the highest ferritin but the lowest Hp concentrations. After adjustments for confounding parameters, the OR of SCS associated with Hp2-2 was 1.74 (95% CI 1.18–2.58; p = 0.005). This effect was enhanced within diabetics (OR 1.90, 95% CI 1.11–3.24; p = 0.018), obese subjects (OR 1.98, 95% CI 1.10–4.86; p = 0.034), and smokers (OR 4.17, 95% CI 1.54–1.29; p = 0.005). The Hp2-2 genotype is associated with an increase in SCS especially in diabetics, the obese, and smokers.