Toll-like receptors: from the discovery of NFkappaB to new insights into transcriptional regulations in innate immunity

Toll-like receptors (TLRs) are key components of the innate immune system, functioning as pattern recognition receptors that recognise a wide range of microbial pathogens. TLRs represent a primary line of defence against invading pathogens in mammals, plants and insects. Recognition of microbial components by TLRs triggers a cascade of cellular signals that culminates in the activation of NFkappaB which leads to inflammatory gene expression and clearance of the infectious agent. The history of NFkappaB began with the TLR4 ligand lipopolysaccharide (LPS), a component of the cell wall of Gram-negative bacteria, since this was the stimulus first used to activate NFkappaB in pre-B-cells. However, since those early days it has been a circuitous route, made possible by drawing on information provided by many different fields, that has led us not only to the discovery of TLRs but also to an understanding of the complex pathways that lead from TLR ligation to NFkappaB activation. In this review we will summarize the current knowledge of TLR-mediated NFkappaB activation, and also the recent discoveries that subtle differences in kappaB binding sequences and NFkappaB dimer formation result in specific gene expression profiles.     

Pharmacotherapy of Candida bloodstream infections: new treatment options,new era

Evolving medical practices and the widespread use of fluconazole have clearly affected the spectrum of invasive mycoses now encountered by clinicians. The proportion of infections due to azole-resistant Candida species and invasive moulds has increased steadily over the last decade, creating a need for broad-spectrum antifungal agents with safety profiles similar to fluconazole. Efforts to address this need have lead to the reformulation of older, broad-spectrum antifungals and the development of new agents with enhanced activity against non-C. albicans and Aspergillus species. This review highlights pharmacodynamic, pharmacokinetic, safety and cost considerations for current and emerging antifungal therapies to be used in the treatment of bloodstream candidiasis.     

Pharmacotherapy of Candida bloodstream infections: new treatment options,new era

Evolving medical practices and the widespread use of fluconazole have clearly affected the spectrum of invasive mycoses now encountered by clinicians. The proportion of infections due to azole-resistant Candida species and invasive moulds has increased steadily over the last decade, creating a need for broad-spectrum antifungal agents with safety profiles similar to fluconazole. Efforts to address this need have lead to the reformulation of older, broad-spectrum antifungals and the development of new agents with enhanced activity against non-C. albicans and Aspergillus species. This review highlights pharmacodynamic, pharmacokinetic, safety and cost considerations for current and emerging antifungal therapies to be used in the treatment of bloodstream candidiasis.     

Placebo: new insights into an old enigma

Our understanding of the placebo effect has deepened through intensive research activity during recent years. It seems important to make a clear distinction between the placebo effect in clinical trials and the placebo effect in clinical practice. In the first scenario, our effects are directed towards minimising its influence on the results whereas, in the second scenario, we might consider maximising it for the benefit of the patient. It also seems important to differentiate between the 'true' and the 'perceived' placebo effect. The 'perceived' placebo effect equals the 'true' placebo effect plus a multitude of other factors. This article reviews new research on the mechanisms of placebo effects, discusses the role of placebos in clinical trials and explores the place of placebo in clinical practice. It concludes that a better understanding of this area will probably benefit basic research, clinical research and patient care.     

Bronchial hyperresponsiveness: insights into new signaling molecules

Signaling molecules play a critical role in the pathophysiology of airway diseases. Recent evidence shows that cyclic ADP-ribose (cADPr), an endogenous activator of the ryanodine receptor channel in mammalian cells, modulates agonist-induced calcium responses in airway smooth muscle (ASM) cells. In addition, cADPr-mediated calcium release appears to play an important role in the "non-specific" increased ASM responsiveness to contractile agonists in cytokine-treated cells, a characteristic finding of asthma. Furthermore, other signaling molecules such as Rho/Rho kinase and phosphodiesterase also contribute to bronchial hyperresponsiveness. Thus, a better understanding of these signaling molecules that alter calcium signaling and contractility of ASM might provide new insight into novel therapeutic targets for the control of bronchial hyperresponsiveness.     

Transglutaminase: new insights into gelatin nanoparticle cross-linking

Gelatin nanoparticles (GNPs) have demonstrated to be beneficial as a biodegradable and biocompatible delivery system. So far, nanoparticles prepared by the two-step desolvation technique were subsequently cross-linked by glutaraldehyde to guarantee storage stability. Although in?vivo and in?vitro toxicological studies have not revealed any glutaraldehyde related undesired effects, an alternative to chemical cross-linking could ease future clinical use in humans. Therefore, the recombinant enzyme microbial transglutaminase was used to examine its cross-linking abilities in nanoparticle production. Various process parameters, such as incubation time, temperature, medium, pH and the particle purification were evaluated regarding their impact on particle size and its distribution. Cross-linking reactions were best at 25°C using an ion-free solvent at a neutral pH and have been terminated after 12?h. Preliminary storage stability testing indicated adequate consistency of particle size and particle distribution making transglutaminase a potential candidate for glutaraldehyde substitution in future GNP production.     

Pharmacophore development for corticotropin-releasing hormone: new insights into inhibitor activity.

Corticotropin-releasing hormone (CRH) is an endogenous 41-amino acid peptide involved in a wide ranging series of systems including the brain, the coordination of the body's overall response to stress, and more recently as a crucial initiator in the onset of labor, also known as the placental clock. Although more physiological data on CRH is emerging shedding more light on the processes involved and their integration, the mode of action of the hormone and the postulated binding site(s) remain unknown. Recently, a number of small-molecular-weight ligands have emerged as potent antagonists but, as therapeutics, suffer from a lack of solubility. Additionally, despite a number of exhaustively large patents, the lack of structural diversity with these antagonists has enabled little scope for comprehensive and wide ranging studies into the structure of the binding sites of this hormone. As part of a program investigating new, structurally diverse antagonists and agonists of CRH, we have developed a preliminary pharmacophore based on the known small-molecular-weight ligands as an initial step in our program. This pharmacophore was validated by comparison with some of the compounds we postulated to be active.     

Nosocomial bloodstream infections due to Candida spp. in the USA: species distribution,clinical features and antifungal susceptibilities

Candida spp. are among the most frequent nosocomial pathogens, contributing significantly to morbidity and mortality. Longitudinal data on the epidemiology of Candida bloodstream infections (BSIs) are still limited. Isolates and clinical data from 1218 episodes of Candida BSI were prospectively collected from patients in 52 hospitals in the USA between 1998 and 2006. Susceptibilities to amphotericin B, flucytosine, fluconazole, posaconazole, voriconazole, anidulafungin, caspofungin and micafungin were determined for 1077 Candida isolates by the CLSI reference broth microdilution method using the recently published species-specific clinical breakpoints. Candida albicans was the most prevalent species (50.7%), followed by Candida parapsilosis (17.4%), Candida glabrata (16.7%) and Candida tropicalis (10.2%). The prevalence of non-albicans Candida spp. increased over time. Patients had a mean age of 51 years and a mean length of hospital stay prior to BSI of 22 days. The main underlying conditions were gastrointestinal (20.1%) and pulmonary (13.0%) diseases. Intravenous catheters (19.1%) and the urinary tract (8.0%) were the most frequently determined likely sources, whilst in the majority of patients (61.1%) no source could be identified. Overall mortality was 38.1%. Of the isolates studied, 0.8% of C. albicans, 100.0% of C. glabrata, 2.9% of C. parapsilosis and 4.9% of C. tropicalis were non-susceptible to fluconazole, and 0.6% of C. albicans, 5.0% of Candida krusei, 7.6% of C. parapsilosis and 9.8% of C. tropicalis were non-susceptible to voriconazole. All echinocandins showed good activity against most Candida spp., including the majority of C. parapsilosis isolates, but only 38.1% of C. glabrata tested susceptible to caspofungin.     

new insights into prostaglandins and mucosal defence

A role for prostaglandins in maintaining mucosal integrity in the gastrointestinal tract is well documented. While traditionally the effects of prostaglandins on mucosal blood flow and epithelial function have been regarded as critical in the mechanism of action of these fatty acids, recent evidence that mucosal ulceration is almost invariably associated with mucosal inflammation has caused a reevaluation of the role of prostaglandins in mucosal defence. This review focuses on the ability of prostaglandins to exert anti-inflammatory, and therefore anti-ulcerogenic, effects in the gastrointestinal tract. These effects of prostaglandins are attributable to their ability to suppress the release of inflammatory mediators and reactive oxygen metabolites from a number of immunocytes, stromal cells and inflammatory cells. There is emerging evidence for cooperative interactions between prostaglandins and nitric oxide in maintaining mucosal integrity. Recent work on the inducible isoform of prostaglandin synthase as it pertains to mucosal defence is also reviewed.     

Targeting Candida spp. to develop antifungal agents

Schematic of the main Candida targets for antifungal agent development, and their cytolocalization. Abbreviations, Ade2, phosphoribosylaminoimidazole carboxylase; AIR, 5-aminoimidazole ribonucleotide; CHS, chitin synthase enzymes; Erg6, sterol 24-C-methyltransferase; Fks1, β-1,3-glucan synthase catalytic subunit; Flu1, fluconazole resistance protein; Mdr1, multidrug resistance protein; Mnt1, α-1,2-mannosyltransferase; Phr1, pH-responsive protein 1; Phr2, pH-responsive protein 2; Plb1, Phospholipase B 1; Ssk1, oxidative stress response two-component system protein; Tps1, α-trehalose-phosphate synthase (UDP-forming); Tps2, trehalose-phosphatase.

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Analysis of Ig/Ig two-component-determined circulating immune complexes (TCIC) provide new insights into host immunity

There have been many reports on circulating immune complexes (CIC), but information regarding Ig/Ig two-component-determined circulating immune complexes (TCIC) is not available. In the present study, we measured the levels of heterogeneous Ig/Ig two-component-determined circulating immune complexes (Ig/Ig-TCIC) in healthy individuals and patients with hepatitis A, Graves' disease and gastric cancer. The heterogeneous Ig/Ig-TCIC was dissected into IgM/IgG-TCIC, IgG/IgA-TCIC and IgA/IgM-TCIC by use of coating and detecting antibodies. The current study has been carried out in 383 cases of healthy individuals, 97 cases of hepatitis A, 108 cases of Graves' disease and 126 cases of gastric cancer. We found that changes on the levels of IgM/IgG-TCIC and IgG/IgA-TCIC is a common feature in patients studied in this study. A total of 71.4% and 80% of patients with gastric cancer had decreased IgM/IgG-TCIC and IgG/IgA-TCIC, respectively. In addition, elevated frequencies were found in patients with hepatitis A and Graves' diseases for IgM/IgG-TCIC (51.5% and 38.0%, respectively) and IgG/IgA-TCIC (29.9% and 19.4%, respectively). In summary, our results suggest that Ig/Ig-TCIC may be a hallmark for evaluation of host immunity. Decreased frequency in gastric cancer and increased frequencies in hepatitis A and Graves' disease forms a peculiar trait for detection of IgM/IgG-TCIC and IgG/IgA-TCIC. Our findings have, thus, provided new insights into circulating immune complexes.     

Invasive Candida infections in the neonate.

Advances in medical therapy have increased premature infant survival. A rise in Candida infections in neonatal intensive care units (NICUs) has followed. Once considered a contaminant, Candida is now recognized as a major cause of mortality and morbidity within these units. We will examine what is known about the epidemiology, risk factors and end-organ involvement of Candida infections with a focus on invasive disease. In addition, diagnostic alternatives to traditional blood culture, experience with antifungal agents for prophylaxis and therapeutic options, including newer antifungal agents, will be presented.     

Crystal forms of torasemide: new insights.

Crystallization from various organic solvents results in three crystal forms of torasemide: monotropically related mod. I (melting point, 158-161 degrees C) and mod. II (melting point, 155-158 degrees C), as well as a pseudopolymorphic crystal form (form A, channel inclusion compound with 1.9-4.2% water and alcohol). Physicochemical properties were determined by thermoanalysis (hot-stage microscopy, differential scanning calorimetry, thermogravimetry), Fourier transform infra-red and Raman spectroscopy, and X-ray powder diffractometry. The hygroscopicity, relative stability, true density, and heat of solutions were determined, respectively. The dissolution behaviour of mod. I and II was investigated as a function of pH, temperature, and in addition to surfactants. Mod. II is nearly three times more soluble than mod. I (mod. I, 0.34 mmol l(-1); mod. II, 0.93 mmol l(-1) at 20 degrees C, pH 4.90) and proved to be highly kinetically stable. By crystallization from 1-butanol, a new compound was synthesized, which was identified as [[4-[(3-Methylphenyl)amino]-3-pyridinyl]sulfonyl]-carbamic acid, butyl ester (TOBC). The most important properties of this torasemide derivative are given. The present results give a thorough physicochemical characterization of the crystal forms of torasemide. They clearly indicate a mistaken identity of mod. II with crystal form A in formerly published articles.     

Review article: new insights into the pathogenesis of radiation-induced intestinal dysfunction

Exposure of the abdomino-pelvic region to ionizing radiation, such as that received during radiotherapy, is associated with the development of a number of untoward symptoms which may limit the course of therapy or which may involve serious chronic intestinal disease. While the mucosal dysfunction surrounding acute radiation enteritis is generally ascribed to the effects of ionizing radiation on the cell cycle of epithelial stem cells of the intestinal crypts and subsequent epithelial loss, recent evidence suggests that other, earlier events also play a role. The severity of these early events may determine the incidence and severity of chronic enteritis. The mechanism for this is unclear, but may relate to radiation-induced compromise of host defence responses to luminal pathogens or antigens. This review will address the current state of knowledge of the pathogenesis of radiation-induced intestinal dysfunction, focusing on events which occur in the mucosa, and will discuss what the future may hold with respect to the treatment of radiation-associated diseases of the intestinal tract.