Oxygen‐dependent delayed fluorescence of protoporphyrin IX measured in the stomach and duodenum during upper gastrointestinal endoscopy

Protoporphyrin IX‐triplet state lifetime technique (PpIX‐TSLT) is a method used to measure oxygen (PO₂) in human cells. The aim of this study was to assess the technical feasibility and safety of measuring oxygen‐dependent delayed fluorescence of 5‐aminolevulinic acid (ALA)‐induced PpIX during upper gastrointestinal (GI) endoscopy. Endoscopic delayed fluorescence measurements were performed 4 hours after oral administration of ALA in healthy volunteers. The ALA dose administered was 0, 1, 5 or 20 mg/kg. Measurements were performed at three mucosal spots in the gastric antrum, duodenal bulb and descending duodenum with the catheter above the mucosa and while applying pressure to induce local ischemia and monitor mitochondrial respiration. During two endoscopies, measurements were performed both before and after intravenous administration of butylscopolamine. Delayed fluorescence measurements were successfully performed during all 10 upper GI endoscopies. ALA dose of 5 mg/kg showed adequate signal‐to‐noise ratio (SNR) values >20 without side effects. All pressure measurements showed significant prolongation of delayed fluorescence lifetime compared to measurements performed without pressure (P < .001). Measurements before and after administration of butylscopolamine did not differ significantly in the duodenal bulb and descending duodenum. Measurements of oxygen‐dependent delayed fluorescence of ALA‐induced PpIX in the GI tract during upper GI endoscopy are technically feasible and safe.     

Use of data envelopment analysis to benchmark environmental product declarations—a suggested framework

The International Journal of Life Cycle Assessment - Environmental product declarations (EPDs) are standardized tools based on life cycle assessment (LCA) to communicate and compare environmental...     

Functional and structural characterization of synthetic cardosin B-derived rennet

The potential of using a synthetic cardosin-based rennet in cheese manufacturing was recently demonstrated with the development and optimization of production of a recombinant form of cardosin B in Kluyveromyces lactis. With the goal of providing a more detailed characterization of this rennet, we herein evaluate the impact of the plant-specific insert (PSI) on cardosin B secretion in this yeast, and provide a thorough analysis of the specificity requirements as well as the biochemical and structural properties of the isolated recombinant protease. We demonstrate that the PSI domain can be substituted by different linker sequences without substantially affecting protein secretion and milk clotting activity. However, the presence of small portions of the PSI results in dramatic reductions of secretion yields in this heterologous system. Kinetic characterization and specificity profiling results clearly suggest that synthetic cardosin B displays lower catalytic efficiency and is more sequence selective than native cardosin B. Elucidation of the structure of synthetic cardosin B confirms the canonical fold of an aspartic protease with the presence of two high mannose-type, N-linked glycan structures; however, there are some differences in the conformation of the flap region when compared to cardosin A. These subtle variations in catalytic properties and the more stringent substrate specificity of synthetic cardosin B help to explain the observed suitability of this rennet for cheese production.     

First trimester screening for trisomy 21 in gestational week 8-10 by ADAM12-S as a maternal serum marker

Background  

A disintegrin and metalloprotease 12 (ADAM12-S) has previously been reported to be significantly reduced in maternal serum from women with fetal aneuploidy early in the first trimester and to significantly improve the quality of risk assessment for fetal trisomy 21 in prenatal screening. The aim of this study was to determine whether ADAM12-S is a useful serum marker for fetal trisomy 21 using the mixture model.     

6-Amino-4-oxo-1,3-diphenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonyl derivatives as a new class of potent inhibitors of Interleukin-8-induced neutrophil chemotaxis

A series of 6-amino-4-oxo-1,3-diphenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonyl derivatives was synthesized. The compounds demonstrated to be novel, potent and selective inhibitors of Interleukin-8-induced human neutrophil chemotaxis. A SAR study was performed by varying the carbonyl function at position 5 and the chain linked to the amino group at position 6 of the scaffold. All the compounds of the series displayed inhibitory activity at nano- or picomolar concentrations against Interleukin-8-driven migration and no activity against fMLP- and C5a-induced chemotaxis. The binding tests of selected compounds on CXCR1 and CXCR2 receptors were negative. The most potent derivative showed in vivo efficacy in a mouse model of Zymosan-induced peritonitis.     

Antimalarial acridines: Synthesis,in vitro activity against P. falciparum and interaction with hematin

A series of acridine derivatives were synthesised and their in vitro antimalarial activity was evaluated against one chloroquine-susceptible strain (3D7) and three chloroquine-resistant strains (W2, Bre1 and FCR3) of Plasmodium falciparum. Structure–activity relationship showed that two positives charges as well as 6-chloro and 2-methoxy substituents on the acridine ring were required to exert a good antimalarial activity. The best compounds possessing these features inhibited the growth of the chloroquine-susceptible strain with an IC₅₀ ? 0.07 μM, close to that of chloroquine itself, and that of the three chloroquine-resistant strains better than chloroquine with IC₅₀ ? 0.3 μM. These acridine derivatives inhibited the formation of β-hematin, suggesting that, like CQ, they act on the haem crystallization process. Finally, in vitro cytotoxicity was also evaluated upon human KB cells, which showed that one of them 9-(6-ammonioethylamino)-6-chloro-2-methoxyacridinium dichloride 1 displayed a promising antimalarial activity in vitro with a quite good selectivity index versus mammalian cell on the CQ-susceptible strain and promising selectivity on other strains.     

On the mechanisms involved in biological heme crystallization

Blood-feeding organisms digest hemoglobin, releasing large quantities of heme inside their digestive tracts. Free heme is very toxic, and these organisms have evolved several mechanisms to protect against its deleterious effects. One of these adaptations is the crystallization of heme into the dark-brown pigment hemozoin (Hz). Here we review the process of Hz formation, focusing on organisms other than Plasmodium that have contributed to a better understanding of heme crystallization. Hemozoin has been found in several distinct classes of organisms including protozoa, helminths and insects and Hz formation is the predominant form of heme detoxification. The available evidence indicates that amphiphilic structures such as phospholipid membranes and lipid droplets accompanied by specific proteins play a major role in heme crystallization. Because this process is specific to a number of blood-feeding organisms and absent in their hosts, Hz formation is an attractive target for the development of novel drugs to control illnesses associated with these hematophagous organisms.     

Identification of the human salivary cystatin complex by the coupling of high-performance liquid chromatography and ion-trap mass spectrometry

Human salivary cystatins, five major (S, S1, S2, SA, SN) and two minor (C and D), are multifunctional proteins playing a different role in the oral environment. Salivary cystatin SN is able to effectively inhibit lysosomal cathepsins B, C, H and L and cystatin SA inhibits cathepsins C and L in vitro. These activities suggest, particularly for cystatin SN, an important role in the control of proteolytic events in vivo. Differently, cystatins S are involved, together with statherin, in the mineral balance of the tooth. Due to their distinct role, a reliable method for identification and quantification of the different cystatins, as well as of possible truncated and derived forms, could be helpful for the assessment of the status of the oral cavity. To this purpose high-performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI MS) was applied to the analysis of human saliva obtained from healthy subjects. All known salivary cystatins, with the exception of cystatin C, were detected. Strong evidence was also obtained for the presence in saliva of post-translational modified isoforms of cystatins, which may be related to donor habits. Cystatin SN and cystatins S, S1 and S2 were well separated by HPLC-ESI MS coupling from other components and thus this approach can be successfully applied to their quantification.     

Regulation of microRNA-145 by growth arrest and differentiation

MicroRNA145 (miR145), a tumor suppressor miR, has been reported to inhibit growth of human cancer cells, to induce differentiation and to cause apoptosis, all conditions that result in growth arrest. In order to clarify the functional effects of miR145, we have investigated its expression in diverse conditions and different cell lines. Our results show that miR145 levels definitely increase in differentiating cells and also in growth-arrested cells, even in the absence of differentiation. Increased expression during differentiation sometimes occurs as a late event, suggesting that miR145 could be required either early or late during the differentiation process.