Heat-shock-proteins-antibodies in patients with Helicobacter pylori associated chronic gastritis

Twenty eight patients (15 F, 13 M mean age 37.7 SD +/- 9.93 range 22-55) affected by Helicobacter Pylori infection associated gastritis were studied. HSP 70 Antibodies were found in 21.4% of patients and their mean values were significantly higher in the patients than in the subjects affected by gastritis HP negative used as controls (p = 0.05). This datum was confirmed by Western blotting. The presence of HSP 70 antibodies in the sera of those patients may support the link between the protein and the development and persistence of chronic inflammation in the gastric mucosa.     

Malaria: recent immunological acquisitions and therapeutic prospects

Malaria remains one of the major health problems in many tropical countries. The asymptomatic carrier status is common and about 100% of the children in highly endemic areas have Plasmodium falciparum parasitaemia at any given time. Consequently a case definition based on the mere presence of parasites in the blood is non-informative in terms of measuring morbidity. Acquired clinical and parasitological immunity develop progressively over several years after repeated exposure to infection. Protection is acquired first again death or severe clinical disease, but protection against infection is never complete, moreover it is still not known why some infections are mild an some fatal. Although virulence markers on the parasite have not been identified with certainty, there are some indications that parasites differ in virulence. The genetic composition of human many also play a role in the defence against the parasite, so the immune mechanisms responsible for the acquired immunity remain uncertain. In fact, an infection by Plasmodium falciparum induces a variety of immune responses, including humoral and cellular, which can be specific or non-specific responses, some of which are protective, but against which the parasite has evolved effective escape measures. Vaccines has proven a most effective measure to control infectious diseases, but no consistently effective vaccine has yet developed against a human parasitic disease. A malaria vaccine aimed at disrupting the parasites life cycle at one or more of the three stages (sporozoite or pre-erythrocytic stage, asexual blood or erythrocytic stage, and sexual or sporogonic stage) might be a long-term solution.     

Drug-induced reinstatement to heroin and cocaine seeking: A rodent model of relapse in polydrug use.

The authors investigated several features of polydrug use in rats. Heroin and cocaine were self-administered following responses on different levers, with only 1 drug and 1 lever available on alternate days of training. Four doses of each drug (heroin: 25, 50, 100, and 200 μg/kg/infusion; cocaine: 0.25, 0.5, 1, and 2 mg/kg/infusion) were tested, and each rat was exposed to a single dose combination. Rats readily developed drug-specific and dose-related responding. During extinction, rats displayed a significant bias for responding on the cocaine-associated lever. Priming injections of either cocaine (20 mg/kg) or heroin (0.25 mg/kg) reinstated responding that was selective for the lever previously associated with each drug These results suggest that in this type of polydrug use, drugs have the capacity to activate drug-seeking behavior selectively oriented toward stimuli previously associated with their administration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The consequences of different "lapses" on relapse to heroin seeking in rats.

Although human studies have shown that a lapse, the first violation of abstinence, often induces resumption of drug taking, or relapse, it is not known what aspect of a lapse is critical to relapse or whether this phenomenon can be studied in other species. Rats were trained to self-administer heroin accompanied by a discrete light stimulus. After extinction, different groups experienced different "lapses." Twenty-four hours later, all groups received a test for relapse. It was found that a lapse during which heroin was self-administered, or was presented in close temporal contiguity with lever pressing, induced subsequent heroin seeking. Simple exposure to heroin, or to heroin-related stimuli, during the lapse had little effect on responding in the test for relapse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Advantages and disadvantages of studying the process of relapse in rats: Reply to Baker and Curtin (2002), Bardo (2002), Goeders (2002), Marlatt (2002), and Tiffany and Conklin (2002).

The authors investigated the effects of an episode of heroin self-administration (i.e., lapse) after extinction on subsequent drug seeking in the absence of heroin (i.e., relapse). Reexposure to heroin in the presence of drug seeking was identified as a critical element of a lapse experience, leading to elevated drug seeking on the test of relapse. T. B. Baker and J. J. Curtin (see record 2002-06535-002), G. A. Marlatt (see record 2002-06535-005), and S. T. Tiffany and C. A. Conklin (see record 2002-06535-006) indicate that animal studies fail to model important aspects of human addiction. M. T. Bardo (see record 2002-06535-003) and N. E. Goeders (see record 2002-06535-004) point out specific methodological problems. In spite of these difficulties, the authors' research makes a valuable contribution to the study of relapse by focusing on aspects of learning and memory involved in the transition from lapse to relapse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Uptake of bromide by two wetland plants (Typha latifolia L. and Phragmites australis (Cav.) Trin. ex Steud)

The successful use of bromide (Br-) as a conservative tracer for hydrological tests in wetland systems requires minimal Br- loss due to plant uptake. The uptake of Br- by two wetland plants, cattail (Typha latifolia L.) and reed grass (Phragmites australis (Cav.) Trin. ex Steud), was investigated in greenhouse flow-through microcosms. Concentrations of Br- and other pertinent constituents in sediment pore water were measured at 2 cm depth increments in the sediment column. The vertical Br- concentration profiles in the sediments clearly revealed Br- uptake by T. latifolia and by P. australis. X-ray spectroscopy studies of bromine in plant samples revealed the accumulation of Br- in root and leaf tissues. Plant transpiration was found to significantly concentrate dissolved species in sediments and was accounted for in the calculations of Br uptake rates. Michaelis-Menten kinetics satisfactorily describe Br- uptake by T. latifolia. The uptake of Br- by P. australis, however, showed unique features that could not be described using Michaelis-Menten kinetics. The addition of chloride (Cl-) effectively inhibited Br- uptake, and the uptake of Cl- and Br- by T. latifolia was shown to follow dual-substrate Michaelis-Menten kinetics. Results of this study indicate that the use of Br- for tracer experiments in vegetated wetland systems should be evaluated with great caution.     

Quantitative determination of absolute organohalogen concentrations in environmental samples by X-ray absorption spectroscopy

An in situ procedure for quantifying total organic and inorganic Cl concentrations in environmental samples based on X-ray absorption near-edge structure (XANES) spectroscopy has been developed. Cl 1s XANES spectra reflect contributions from all Cl species present in a sample, providing a definitive measure of total Cl concentration in chemically heterogeneous samples. Spectral features near the Cl K-absorption edge provide detailed information about the bonding state of Cl, whereas the absolute fluorescence intensity of the spectra is directly proportional to total Cl concentration, allowing for simultaneous determination of Cl speciation and concentration in plant, soil, and natural water samples. Absolute Cl concentrations are obtained from Cl 1s XANES spectra using a series of Cl standards in a matrix of uniform bulk density. With the high sensitivity of synchrotron-based X-ray absorption spectroscopy, Cl concentration can be reliably measured down to the 5-10 ppm range in solid and liquid samples. Referencing the characteristic near-edge features of Cl in various model compounds, we can distinguish between inorganic chloride (Cl(inorg)) and organochlorine (Cl(org)), as well as between aliphatic Cl(org) and aromatic Cl(org), with uncertainties in the range of approximately 6%. In addition, total organic and inorganic Br concentrations in sediment samples are quantified using a combination of Br 1s XANES and X-ray fluorescence (XRF) spectroscopy. Br concentration is detected down to approximately 1 ppm by XRF, and Br 1s XANES spectra allow quantification of the Br(inorg) and Br(org) fractions. These procedures provide nondestructive, element-specific techniques for quantification of Cl and Br concentrations that preclude extensive sample preparation.     

Structural Features and Toxicity of α-Synuclein Oligomers Grown in the Presence of DOPAC

The interplay between α-synuclein and dopamine derivatives is associated with oxidative stress-dependent neurodegeneration in Parkinson’s disease (PD). The formation in the dopaminergic neurons of intraneuronal inclusions containing aggregates of α-synuclein is a typical hallmark of PD. Even though the biochemical events underlying the aberrant aggregation of α-synuclein are not completely understood, strong evidence correlates this process with the levels of dopamine metabolites. In vitro, 3,4-dihydroxyphenylacetaldehyde (DOPAL) and the other two metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylethanol (DOPET), share the property to inhibit the growth of mature amyloid fibrils of α-synuclein. Although this effect occurs with the formation of differently toxic products, the molecular basis of this inhibition is still unclear. Here, we provide information on the effect of DOPAC on the aggregation properties of α-synuclein and its ability to interact with membranes. DOPAC inhibits α-synuclein aggregation, stabilizing monomer and inducing the formation of dimers and trimers. DOPAC-induced oligomers did not undergo conformational transition in the presence of membranes, and penetrated the cell, where they triggered autophagic processes. Cellular assays showed that DOPAC reduced cytotoxicity and ROS production induced by α-synuclein aggregates. Our findings show that the early radicals resulting from DOPAC autoxidation produced covalent modifications of the protein, which were not by themselves a primary cause of either fibrillation or membrane binding inhibition. These findings are discussed in the light of the potential mechanism of DOPAC protection against the toxicity of α-synuclein aggregates to better understand protein and catecholamine biology and to eventually suggest a scaffold that can help in the design of candidate molecules able to interfere in α-synuclein aggregation.     

Cl K-edge X-ray spectroscopic investigation of enzymatic formation of organochlorines in weathering plant material

The contribution of halocarbons from plant weathering to the total organohalogen budget of terrestrial systems is gaining recognition. To evaluate the formation of such halocarbons, speciation of chlorine in Sequoia sempervirens (redwood) needles was examined in the presence of an external chloroperoxidase (CPO) enzyme using Cl K-edge X-ray absorption spectroscopy. The Cl forms in fresh and naturally weathered needles and in model laboratory reactions were compared. To provide a straightforward analogue to the enzymatic chlorination in plants, chlorination reactions were conducted for phenol, a common moiety of plant macromolecules. Plant material chlorination was also examined in the presence of hypochlorite in an ancillary mechanistic investigation. The dominant form of Cl in fresh, unreacted plant material was found to be inorganic Cl-, which was partially converted to organochlorine in the presence of CPO. Chlorination is affected by the nature of reactant (CPO, H2O2) addition, reaction time, and temperature. The organochlorines produced in these laboratory investigations closely resemble those produced during the natural weathering of redwood needles. A striking consistency in chlorine speciation observed among the various sample types suggests that (i) CPO produced by terrestrial organisms could play a vital role in the generation of organochlorines associated with the degradation of plant material and (ii) initial targets of enzymatic chlorination might include lignin-like macromolecules rich in aromatic character and hydroxyl groups. These findings lend further credibility to a significant biogenic contribution to the global organohalogen burden by elucidating a probable route of enzymatic chlorination of natural organic matter in terrestrial systems.