A straightforward synthesis of indazolo[3,2-a]isoquinolin-6-amines

4-Substituted 1-bromoisoquinolin-3-amines were subjected to Suzuki coupling with o-nitrophenylboronic acid to yield 1-(2-nitrophenyl) isoquinolinamines, which participated in Cadogan cyclization with triethyl phosphite under microwave irradiation in a sealed vial to yield fluorescent indazolo[3,2-a]isoquinolin-6-amines. The new compounds were also functionalized by transformation of the amino group.     

Development of split–splitless PTV large-volume injection for analytes covering a wide boiling point range

A programmed-temperature vaporiser (PTV)–large-volume injection (LVI) method with a two-stage evaporation process was developed capable of effectively introducing analytes covering a wide boiling-point range (from that of n-nonane to that of n-tetracontane). The method uses speed-controlled sample introduction (50 µL) and a simple PTV setup with Peltier Cooling. Besides, an important cause of discrimination of high-boiling compounds in LVI was identified. The method was successfully applied to simplify the sample preparation in the extractable petroleum hydrocarbon analysis of water and soil samples. The method proved to be resistant to matrix contamination. Linearity was tested between 0.01 and 20 µg mL^?1. The correlation coefficients ranged from 0.996 to 0.999. The relative standard deviation calculated from five parallel runs was 2.73%. The major advantage of the method is its simplicity making it an attainable choice for smaller environmental laboratories.     

Using the 186-keV peak for 226Ra activity concentration determination in Hungarian coal-slag samples by gamma-ray spectroscopy

The uranium isotopic abundance and the ²³⁸U–²²⁶Ra secular equilibrium were determined in nine Hungarian coal slag samples. The ²²⁶Ra activity concentration was measured based on the radon decay products and also the ²²⁶Ra peak at 186 keV. Secular equilibrium existed in eight samples, whereas one sample showed a slight disequilibrium. The direct and fast measurement using only the 186 keV peak was validated which can be used after measuring the uranium isotopic ratio and verifying the ²³⁸U–²²⁶Ra secular equilibrium. This method can be used to measure the ²²⁶Ra content of high number of samples from the same geochemical background.     

Glycan Side Reaction May Compromise ETD-Based Glycopeptide Identification

Tris(hydroxymethyl)aminomethane (Tris) is one of the most frequently used buffer ingredients. Among other things, it is recommended and is usually used for lectin-based affinity enrichment of glycopeptides. Here we report that sialic acid, a common ‘capping’ unit in both N- and O-linked glycans may react with this chemical, and this side reaction may compromise glycopeptide identification when ETD spectra are the only MS/MS data used in the database search. We show that the modification may alter N- as well as O-linked glycans, the Tris-derivative is still prone to fragmentation both in ‘beam-type’ CID (HCD) and ETD experiments, at the same time—since the acidic carboxyl group was ‘neutralized’—it will display a different retention time than its unmodified counterpart. We also suggest solutions that—when incorporated into existing search engines—may significantly improve the reliability of glycopeptide assignments.

Thermal stability of rat uterus during development

Summary The age dependence of thermal denaturation was monitored in rats anaesthetized after they're born at 7^th, 14^th, 21^st, 28^th, 35^thand 42^nddays. The samples were stored in rigor or physiological saline solution. The DSC scans in the early age groups show a low temperature exotherm (connective tissues: from gel to liquid crystal transition) and one endotherm (it is very probably the myosin). During further development the endotherms became more and more complex (due to the development of contractile system). At 42 days the scans seem to be similar to the adult ones. In the two buffers the endotherms markedly differ showing that the ATPase activity is present. In adult uterus, treated with nucleotides or estrogen, this activity significantly differs from the skeletal muscle. On the basis of our results we suppose, that the age dependent changes are decisive processes in the development of rat uterus.     

A new cyclization to fused pyrazoles tunable for pericyclic or pseudopericyclic route: an experimental and theoretical study

2-Pyrazinyl (2) and 3-pyridazinylketone arylhydrazones (6) and their benzologues undergo a ring closure reaction to yield pyrazolo[3,4- b]pyrazines (4) and pyrazolo[4,3- c]pyridazines (7), respectively, in acceptable to good yields. The reaction was found to be accelerated by using acidic or basic conditions. Quantum chemical calculations suggest the key step of the mechanism to be a direct cyclization; analysis of aromaticity based on computed magnetic properties revealed its medium-dependent pericyclic or pseudopericyclic character. The cyclization reaction has also been extended for the synthesis of related ring systems ( 9, 12, 14).     

Determination of antihypertensive and anti-ulcer agents from surface water with solid-phase extraction-liquid chromatography-electrospray ionization tandem mass spectrometry

Pharmaceuticals are emerging contaminants in surface water and they must be measured to follow their effects on the aquatic environment. We developed a solid-phase extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (SPE-LC-ESI-MS/MS) method for the determination of twenty-six pharmaceutical compounds - which belong to antihypertensive and anti-ulcer agents - from surface water samples. The selection of pharmaceuticals was based on usage frequency in Hungary. During method development Oasis HLB, SampliQ Polymer SCX and Si-SCX SPE cartridges were tested. As LC eluent ammonium formate, ammonium acetate buffers at pH 3 and 5 were investigated and for quantitation both matrix-matched and internal standard calibration was used. For matrix effect assessment post-extraction spike method was applied which can separate the extraction efficiency from ion suppression for better determination of recovery. Method detection limits (MDLs) varied between 0.2 and 10 ng/L. Precision of the method, calculated as relative standard deviation (RSD), ranged from 0.2 to 14.6% and from 1.2 to 22.4% for intra- and inter-day analysis, respectively. The method was applied to analyze Danube water samples. Measured average concentrations varied between 2 and 39 ng/L for eleven compounds and another one could be detected under LOQ.     

Quantitative mass spectrometry for bacterial protein toxins--a sensitive, specific, high-throughput tool for detection and diagnosis

Matrix-assisted laser-desorption time-of-flight (MALDI-TOF) mass spectrometry (MS) is a valuable high-throughput tool for peptide analysis. Liquid chromatography electrospray ionization (LC-ESI) tandem-MS provides sensitive and specific quantification of small molecules and peptides. The high analytic power of MS coupled with high-specificity substrates is ideally suited for detection and quantification of bacterial enzymatic activities. As specific examples of the MS applications in disease diagnosis and select agent detection, we describe recent advances in the analyses of two high profile protein toxin groups, the Bacillus anthracis toxins and the Clostridium botulinum neurotoxins. The two binary toxins produced by B. anthracis consist of protective antigen (PA) which combines with lethal factor (LF) and edema factor (EF), forming lethal toxin and edema toxin respectively. LF is a zinc-dependent endoprotease which hydrolyzes specific proteins involved in inflammation and immunity. EF is an adenylyl cyclase which converts ATP to cyclic-AMP. Toxin-specific enzyme activity for a strategically designed substrate, amplifies reaction products which are detected by MALDI-TOF-MS and LC-ESI-MS/MS. Pre-concentration/purification with toxin specific monoclonal antibodies provides additional specificity. These combined technologies have achieved high specificity, ultrasensitive detection and quantification of the anthrax toxins. We also describe potential applications to diseases of high public health impact, including Clostridium difficile glucosylating toxins and the Bordetella pertussis adenylyl cyclase.     

A two-phase decision support framework for the automatic screening of digital fundus images

In this paper we give a brief review on the present status of automated detection systems describe for the screening of diabetic retinopathy. We further detail an enhanced detection procedure that consists of two steps. First, a pre-screening algorithm is considered to classify the input digital fundus images based on the severity of abnormalities. If an image is found to be seriously abnormal, it will not be analysed further with robust lesion detector algorithms. As a further improvement, we introduce a novel feature extraction approach based on clinical observations. The second step of the proposed method detects regions of interest with possible lesions on the images that previously passed the pre-screening step. These regions will serve as input to the specific lesion detectors for detailed analysis. This procedure can increase the computational performance of a screening system. Experimental results show that both two steps of the proposed approach are capable to efficiently exclude a large amount of data from further processing, thus, to decrease the computational burden of the automatic screening system.     

Pinus sylvestris L. and Syzygium aromaticum (L.) Merr. & L. M. Perry Essential Oils Inhibit Endotoxin-Induced Airway Hyperreactivity despite Aggravated Inflammatory Mechanisms in Mice

Scots pine (SO) and clove (CO) essential oils (EOs) are commonly used by inhalation, and their main components are shown to reduce inflammatory mediator production. The aim of our research was to investigate the chemical composition of commercially available SO and CO by gas chromatography–mass spectrometry and study their effects on airway functions and inflammation in an acute pneumonitis mouse model. Inflammation was evoked by intratracheal endotoxin and EOs were inhaled three times during the 24 h experimental period. Respiratory function was analyzed by unrestrained whole-body plethysmography, lung inflammation by semiquantitative histopathological scoring, myeloperoxidase (MPO) activity and cytokine measurements. α-Pinene (39.4%) was the main component in SO, and eugenol (88.6%) in CO. Both SO and CO significantly reduced airway hyperresponsiveness, and prevented peak expiratory flow, tidal volume increases and perivascular edema formation. Meanwhile, inflammatory cell infiltration was not remarkably affected. In contrast, MPO activity and several inflammatory cytokines (IL-1β, KC, MCP-1, MIP-2, TNF-α) were aggravated by both EOs. This is the first evidence that SO and CO inhalation improve airway function, but enhance certain inflammatory parameters. These results suggest that these EOs should be used with caution in cases of inflammation-associated respiratory diseases.