Characterization of chitosan hydrochloride–mucin interaction by means of viscosimetric and turbidimetric measurements

In the present work the interaction between chitosan hydrochloride (HCS) and two different types of mucin – one obtained from bovine submaxillary glands and the other from porcine stomach – was investigated. Two hydration media were tested: distilled water and 0.1 M HCl. Intrinsic viscosity, which provides information about polymeric chain conformation, was assessed in both media for HCS and bovine submaxillary mucin. Changes in the specific viscosity of HCS–mucin mixtures were observed as a function of the polymer:mucin weight ratio. The formation of interaction products was indicated by a minimum in the specific viscosity. Such a minimum occurred at different polymer:mucin weight ratios depending on the hydration medium and mucin type. This suggested a different stoichiometry of interaction. Turbidimetric measurements were also effected in order to evidentiate the eventual precipitation of the polymer–mucin interaction products. While in distilled water the precipitation of the interaction product did occur, in acidic medium, although a minimum in specific viscosity was observed, no precipitate was formed. The two techniques employed, viscosimetric and turbidimetric, allowed us to investigate for both mucins the influence of hydration medium on the formation of the HCS–mucin interaction products and to conclude that a slightly acid–neutral pH favours the interaction between HCS and mucins.     

纤维蛋白降解产物、D-二聚体等生化指标用于矽肺早期诊断的探讨

目的 探讨纤维蛋白降解产物（ＦＤＰ）、Ｄ－二聚体（Ｄ－ｄｉｍｅｒ）等指标用于矽肺早期诊断的意义和价值。方法 对无矽肺０＾＋者,Ⅰ期矽肺患者进行六项指标的测定。结果 经方差分析,０＾＋组中铜蓝蛋白（ＣＰ）、血清羟脯氨酸（ＨＹＰ）、丙二醛（ＭＤＡ）、超氧化物歧化酶（ＳＯＤ）及ＦＤＰ均高于正常对照组,Ⅰ期组的ＣＰ、ＭＤＡ、ＨＹＰ、Ｄ－ｄｉｍｅｒ水平均高于０＾＋组。判别分析表明,ＣＰ、ＭＤＡ、ＨＹＰ、Ｄ－     

Antimicrobial chemical constituents from endophytic fungus Phoma sp.

Objective:To evaluate the antiniicrobial polenlial of different extracts of the endophytic fungus Phoma sp.and the tentative identification of their active constituents.Methods:The extract and compounds were screened for antimicrobial activity using the Agar Well Diffusion Method.Four compounds were purified using column chromatography and tlieir structures were assigned using～1H and～(13)C NMR spectra,DEPT,2D COSY,HMQC and HMBC experiments.Results:The ethyl acetate fraction of Phoma sp.showed good antifungal,antibacterial,and algicidal properties.One new dihydrofuran derivative,named phomafuranol(1),together with tliree known compounds,phomalacton(2),(3R)-5-hydroxymellein(3)and emodin(4)were isolated from the ethyl acetate fraction of Phoma sp.Preliminary studies indicated that phomalacton(2)displayed strong antibacterial,good antifungal and antialgal activities.Similarly(3R)-5-hydroxymellein(3)and emodin(4)showed good antifungal,antibacterial and algicidal properties.Conclusions:Antimicrobial activities of the ethyl acetate fraction of the endophytic fungus Phoma sp.and isolated compounds clearly demonstrate that Phoma sp.and its active compounds represent a great potential for the food,cosmetic and pharmaceutical industries.     

Autonomic nerves and perivascular fat: Interactive mechanisms

The evidence describing the autonomic innervation of body fat is reviewed with a particular focus on the role of the sympathetic neurotransmitters. In compiling the evidence, a strong case emerges for the interaction between autonomic nerves and perivascular adipose tissue (PVAT). Adipocytes have been shown to express receptors for neurotransmitters released from nearby sympathetic varicosities such as adrenoceptors (ARs), purinoceptors and receptors for neuropeptide Y (NPY). Noradrenaline can modulate both lipolysis (via α₂- and β₃-ARs) and lipogenesis (via α₁- and β₃-ARs). ATP can inhibit lipolysis (via P₁ purinoceptors) or stimulate lipolysis (via P_2y purinoceptors). NPY, which can be produced by adipocytes and sympathetic nerves, inhibits lipolysis. Thus the sympathetic triad of transmitters can influence adipocyte free fatty acid (FFA) content. Substance P (SP) released from sensory nerves has also been shown to promote lipolysis. Therefore, we propose a mechanism whereby sympathetic neurotransmission can simultaneously activate smooth muscle cells in the tunica media to cause vasoconstriction and alter FFA content and release from adjacent adipocytes in PVAT. The released FFA can influence endothelial function. Adipocytes also release a range of vasoactive substances, both relaxing and contractile factors, including adiponectin and reactive oxygen species. The action of adipokines (such as adiponectin) and reactive oxygen species (ROS) on cells of the vascular adventitia and nerves has yet to be fully elucidated. We hypothesise a strong link between PVAT and autonomic fibres and suggest that this poorly understood relationship is extremely important for normal vascular function and warrants a detailed study.     

Secretory products of helminth parasites as immunomodulators

Parasitic helminths release molecules into their environment, which are generally referred to as excretory-secretory products or ES. ES derived from a wide range of nematodes, trematodes and cestodes have been studied during the past 30–40 years, their characterization evolving from simple biochemical procedures such as SDS-PAGE in the early days to sophisticated proteomics in the 21st century. Study has incorporated investigation of ES structure, potential as vaccines, immunodiagnostic utility, functional activities and immunomodulatory properties. Immunomodulation by ES is increasingly the area of most intensive research with a number of defined helminth products extensively analyzed with respect to the nature of their selective effects on cells of the immune system as well as the molecular mechanisms, which underlie these immunomodulatory effects. As a consequence, we are now beginning to learn the identities of the receptors that ES employ and are increasingly acquiring detailed knowledge of the signalling pathways that they interact with and subvert. Such information is contributing to the growing idea that the anti-inflammatory properties of a number of ES products makes them suitable starting points for the development of novel drugs for treating human inflammatory disease.     

Studying the immune response to human viral infections using zebrafish

Humans and viruses have a long co-evolutionary history. Viral illnesses have and will continue to shape human history: from smallpox, to influenza, to HIV, and beyond. Animal models of human viral illnesses are needed in order to generate safe and effective antiviral medicines, adjuvant therapies, and vaccines. These animal models must support the replication of human viruses, recapitulate aspects of human viral illnesses, and respond with conserved immune signaling cascades. The zebrafish is perhaps the simplest, most commonly used laboratory model organism in which innate and/or adaptive immunity can be studied. Herein, we will discuss the current zebrafish models of human viral illnesses and the insights they have provided. We will highlight advantages of early life stage zebrafish and the importance of innate immunity in human viral illnesses. We will also discuss viral characteristics to consider before infecting zebrafish with human viruses as well as predict other human viruses that may be able to infect zebrafish.     

High-resolution 1H NMR investigations of the oxidative consumption of salivary biomolecules by oral rinse peroxides

Abstract

Background. A multicomponent evaluation of the oxidative consumption of salivary biomolecules by a tooth-whitening oral rinse preparation has been performed using high-resolution proton (¹H) nuclear magnetic resonance spectroscopy (NMR). Methods. Unstimulated human saliva samples (n = 12) were treated with aliquots of the oral rinse tested and 600 MHz ¹H NMR spectra acquired on these samples demonstrated that hydrogen peroxide (H₂O₂) and/or peroxodisulphate (S₂O₈ ^2–) present in this product gave rise to the oxidative decarboxylation of the salivary electron-donor pyruvate (to acetate and CO₂), and also oxidized methionine (a precursor to volatile sulphur compounds responsible for oral malodour), and malodourous trimethylamine to methionine sulphoxide and trimethylamine-N-oxide, respectively (reductions observed in the salivary concentrations of each biomolecular peroxide-scavenging agent were all extremely statistically significant, p < 0.005). Results. Experiments conducted on chemical model systems confirmed the consumption of pyruvate by this product, and also revealed that the amino acids cysteine and methionine were oxidatively transformed to cystine and methionine sulphoxide, respectively. Conclusions. High-field ¹H NMR analysis provides much valuable molecular information regarding the fate of tooth-whitening oxidants in human saliva and permits an assessment of the mechanisms of action of oral healthcare products containing these agents. The biochemical and potential therapeutic significance of the results obtained are discussed.