Depression is a leading cause of disability worldwide and improving its treatment is a core research priority for future programmes. A change in the view of psychological and biological processes, ...from seeing them as separate to complementing one another, has introduced new perspectives on pathological mechanisms of depression and treatment mode of action. This review presents a theoretical model that incorporated this novel approach, the cognitive neuropsychological hypothesis of antidepressant action. This model proposes that antidepressant treatments decrease the negative bias in the processing of emotionally salient information early in the course of antidepressant treatment, which leads to the clinically significant mood improvement later in treatment. The paper discusses the role of negative affective biases in the development of depression and response to antidepressant treatments. It also discusses whether the model can be applied to other antidepressant interventions and its potential translational value, including treatment choice, prediction of response and drug development.
New antidepressants and individualized approaches to treatment, matching specific therapies to individual patients, are urgently needed. For this, a better understanding of processes underpinning the ...development of depressive symptoms and response to medications are required. The cognitive neuropsychological model offers a novel approach uniquely combining biological and psychological approaches to explain how antidepressants exert their effect, why there is a delay in the onset of their clinical effect, and how changes in emotional processing are an essential step for a clinical antidepressant effect to take place. The paper presents the model and its underpinnings in the form of research in both healthy and depressed individuals, as well as the potential for its practical use.
The present study was undertaken to test the influence of exogenously applied phytohormones: auxins (IAA, IBA, NAA, PAA), cytokinins (BA, CPPU, DPU, 2iP, Kin, TDZ, Z), gibberellin (GA3), jasmonic ...acid (JA) as well as polyamine - spermidine (Spd) upon the growth and metabolism of green microalga Chlorella vulgaris (Chlorophyceae) exposed to heavy metal (Cd, Cu, Pb) stress. The inhibitory effect of heavy metals on algal growth, metabolite accumulation and enzymatic as well as non-enzymatic antioxidant system was arranged in the following order: Cd > Pb > Cu. Exogenously applied phytohormones modify the phytotoxicity of heavy metals.
Auxins, cytokinins, gibberellin and spermidine (Spd) can alleviate stress symptoms by inhibiting heavy metal biosorption, restoring algal growth and primary metabolite level. Moreover, these phytohormones and polyamine stimulate antioxidant enzymes’ (superoxide dismutase, ascorbate peroxidase, catalase) activities and ascorbate as well as glutathione accumulation by producing increased antioxidant capacity in cells growing under abiotic stress. Increased activity of antioxidant enzymes reduced oxidative stress expressed by lipid peroxidation and hydrogen peroxide level. In contrast JA enhanced heavy metal toxicity leading to increase in metal biosorption and ROS generation. The decrease in cell number, chlorophylls, carotenoids, monosaccharides, soluble proteins, ascorbate and glutathione content as well as antioxidant enzyme activity was also obtained in response to JA and heavy metals. Determining the stress markers (lipid peroxidation, hydrogen peroxide) and antioxidants’ level as well as antioxidant enzyme activity in cells is important for understanding the metal-specific mechanisms of toxicity and that these associated novel endpoints may be useful metrics for accurately predicting toxicity. The data suggest that phytohormones and polyamine play an important role in the C. vulgaris responding to abiotic stressor and algal adaptation ability to metal contamination of aquatic environment.
Auxins, cytokinins, gibberellin, jasmonic acid and spermidine can regulate heavy metal (Cd, Cu, Pb) biosorption and modify their toxic effect on Chlorella vulgaris growth, primary metabolite level and antioxidant system. Display omitted
► Heavy metals toxicity in C. vulgaris was arranged in the following order: Cd>Pb>Cu. ► Auxins, cytokinins, gibberellin and polyamine can alleviate heavy metals stress. ► Jasmonic acid enhanced harmful effect of heavy metals on algal cells.
The aim of this work was to study by a hyphenated HPLC-ICP MS technique the chromium species released during alkaline extraction of various soils collected from a contaminated area of an old tannery. ...An ultrasound-assisted extraction procedure using 0.1 mol L
Na₂CO₃ solution was developed for the release of chromium species from the soil. The chromium species in the soil extracts were separated on a C₈ column using EDTA and TBAH solution as a mobile phase. The use of an ICP-QQQ MS spectrometer in tandem mass configuration (MS/MS) combined with an octopole reaction system (ORS³) pressurized with helium allows one to eliminate spectral interferences during Cr determination in the soil extracts. The detection limit of the procedure was 0.08 µg L
for Cr(III) and 0.09 µg L
for Cr(VI) species. The trueness of the IP RP HPLC-ICP MS method was proved by an analysis of CRM 041 and CRM 060. The advantage of the proposed method is the analysis of soil extracts without their preliminary neutralization, which limits the losses of Cr(VI) due to the reduction process. The analysed soils mainly contained chromium in immobile forms (94.6⁻98.5% of the total Cr content). In all alkaline soil extracts mostly the Cr(VI) form was found, but in the extract of organic soils Cr(III) was also present. This arose from the reduction of Cr(VI) species by organic matter (humic acids) and Fe(II). The amount of formed Cr(III) species was dependent on the type of soil (content of organic matter, Mn and Fe) and its moistness. For the first time, the presence of neutral and non-polar chromium fractions in the soil extracts was also demonstrated. It was found that reliable speciation analysis results could be obtained for mineral soils.
Although depression has been widely researched, findings characterizing how brain regions influence each other remains scarce, yet this is critical for research on antidepressant treatments and ...individual responses to particular treatments.
To identify pre-treatment resting state effective connectivity (rsEC) patterns in patients with major depressive disorder (MDD) and explore their relationship with treatment response.
Thirty-four drug-free MDD patients had an MRI scan and were subsequently treated for 6 weeks with an SSRI escitalopram 10 mg daily; the response was defined as ≥50% decrease in Hamilton Depression Rating Scale (HAMD) score.
rsEC networks in default mode, central executive, and salience networks were identified for patients with depression. Exploratory analyses indicated higher connectivity strength related to baseline depression severity and response to treatment.
Preliminary analyses revealed widespread dysfunction of rsEC in depression. Functional rsEC may be useful as a predictive tool for antidepressant treatment response. A primary limitation of the current study was the small size; however, the group was carefully chosen, well-characterized, and included only medication-free patients. Further research in large samples of placebo-controlled studies would be required to confirm the results.
•Resting state effective connectivity brain networks were identified in patients with major depressive disorder.•Our bayesian variable selection approach allowed for simultaneous inference on rsEC at the subject and group levels.•Results indicate widespread dysfunction of rsEC in depressed adults that predicted treatment response.
Rationale
Magnetic resonance spectroscopy (MRS) is an acceptable non-invasive means of studying brain neurochemistry in depression. Previous studies in depressed patients have focused on measurement ...of the amino acid neurotransmitters, γ-aminobutyric acid (GABA) and glutamate.
Objectives
The aim of this study is to use MRS in conjunction with the ultrashort echo time ‘SPECIAL’ technique to measure cortical levels of GABA, glutamate and glutathione (GSH) levels in unmedicated patients with major depression. We also examined the effect of 6-week treatment with the selective serotonin re-uptake inhibitor, escitalopram.
Methods
We studied patients with DSM-IV major depression and healthy age-matched controls using proton MRS. GABA, glutamate and GSH were measured relative to creatine in a voxel placed in occipital cortex.
Results
There was no difference in GABA or glutamate levels between depressed participants and controls; however, depressed patients had lower GSH levels. Six-week escitalopram treatment, which resulted in significant clinical responses in some patients, did not alter concentrations of GABA, glutamate or GSH.
Conclusions
The sources of variability of GABA and glutamate measures in different studies of depressed patients require further study. Our results suggest that concomitant treatment with selective serotonin re-uptake inhibitors (SSRIs) is unlikely to be an important confounding factor. If lowered GSH levels can be confirmed, they may represent the presence of oxidative stress in some depressed patients.
Interactions of Au(
iii
) and citrate-stabilized gold nanoparticles (AuNPs) of different nominal diameters (10, 20 and 40 nm) with green microalgae
Desmodesmus subspicatus
were studied. Both ...inductively coupled plasma mass spectrometry (ICP MS) and high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP MS) were applied to measure total gold content and AuNP size, respectively. After 24 h exposure of algae to gold species at environmentally relevant concentration, quantitative uptake was observed for Au(
iii
), whereas for AuNPs it was size dependent and increased with increasing particle size. It was found that the surface water matrix has no significant influence on the cell-associated amount of gold as the uptake was comparable for algae suspended in Milli-Q and surface water. To characterise the transformations of gold species in aquatic environments, hydrodynamic diameters of AuNPs in surface water, algal cells and supernatants were determined. Gold species were extracted from algal cells using an optimized ultrasound assisted extraction procedure. The accuracy of size determination was evaluated by analysis of NIST Reference Material 8011 (10 nm AuNPs). Cellular localization and core diameter determinations of AuNPs were performed by transmission electron microscopy (TEM). It was found that the introduction of Au(
iii
) into algal cultures leads to intracellular localization of AuNPs (6-7 nm). The 10, 20 and 40 nm AuNPs did not penetrate inside cells; however, their hydrodynamic size increased after the incubation test due to the formation of a biocorona. The thickness of the biomolecule corona was calculated and it depended on particle size. Despite the observed uptake and transformations of gold species, no effect on algal growth was noticed during the 24 h incubation period at the studied exposure concentration.
Studies elucidate the fate of AuNPs and Au(
iii
) during 24 h incubation in surface water and their interaction with green microalgae cells. A robust methodology for such studies was developed.
Rational
With no available response biomarkers, matching an appropriate antidepressant to an individual can be a lengthy process. Improving understanding of processes underlying treatment ...responsivity in depression is crucial for facilitating work on response biomarkers.
Objectives
To identify differences in patterns of pre-treatment resting-state functional connectivity (rsFC) that may underlie response to antidepressant treatment.
Methods
After a baseline MRI scan, thirty-four drug-free patients with depression were treated with an SSRI escitalopram 10 mg daily for 6 weeks; response was defined as ≥ 50% decrease in Hamilton Depression Rating Scale (HAMD) score. Thirty-one healthy controls had a baseline clinical assessment and scan. Healthy participants did not receive treatment.
Results
Twenty-one (62%) of patients responded to escitalopram. Treatment responsivity was associated with enhanced rsFC of the right fronto-parietal network (FPN)—with the posterior DMN, somatomotor network (SMN) and somatosensory association cortex. The lack of treatment response was characterized by reduced rsFC: of the bilateral FPN with the contralateral SMN, of the right FPN with the posterior DMN, and of the extended sensorimotor auditory area with the inferior parietal lobule (IPL) and posterior DMN. Reduced rsFC of the posterior DMN with IPL was seen in treatment responders, although only when compared with HC.
Conclusions
The study supports the role of resting-state networks in response to antidepressant treatment, and in particular the central role of the frontoparietal and default mode networks.
A new method based on high performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the speciation analysis of silver ...nanoparticles (AgNPs) and dissolved silver forms (Ag(
i
)) in surface water and algal cells. Different compositions of the mobile phase, including surfactants preventing agglomeration/aggregation of AgNPs, pH buffers and complexing agents for silver ions, were carefully investigated to ensure complete elution and stability of silver species during chromatographic analysis. Under the optimal separation conditions (mobile phase: 10 mM sodium dodecyl sulfate, 2 mM citrate buffer, and 2 mM tiopronin), detection limits of 2.0 ng L
−1
for Ag(
i
), 3.1 ng L
−1
for 10 nm AgNPs, and 2.2 ng L
−1
for 30 nm AgNPs were achieved. A linear relationship was found between the retention time of AgNPs and logarithm of particle diameter up to 40 nm, which can be used for the particle size determination in real samples. The HPLC-ICP-MS method has been successfully applied to study interactions of Ag(
i
) and citrate-stabilized AgNPs of different nominal diameters (10 nm and 30 nm) with green microalgae
Acutodesmus obliquus
in river water. The cell-associated fractions of silver were quite similar for all studied forms (silver biosorption was in the range of 77.2-82.7%). As a result of interaction with the biomass, biosynthesis of small nanoparticles (with a size of 6 nm) from Ag(
i
) ions and partial dissolution of 10 and 30 nm AgNPs were observed.
A new HPLC-ICP-MS method has been developed for speciation analysis of AgNPs and dissolved Ag(
i
) in surface water and algal cells.
The emission of platinum group metals from different sources has caused elevated concentrations of platinum and palladium in samples of airborne particulate matter, soil, surface waters and sewage ...sludge. The ability of biomass of Aspergillus sp. and yeast Saccharomyces sp. for removal of Pt(IV) and Pd(II) from environmental samples was studied in this work. The pH of the solution, the mass of biosorbent, and contact time were optimized. The Langmuir and Freundlich adsorption isotherms and kinetic results were used for interpretation of the process equilibrium of Pt(IV) and Pd(II) on both microorganisms. The maximal efficiency of retention of Pt(IV) on yeast and fungi was obtained at acidic solutions (pH 2.0 for Pt(IV) and pH 2.5–3.5 for Pd(II)). The equilibrium of the biosorption process was attained within 45 min. The best interpretation for the experimental data was given by the Langmuir isotherm. Kinetics of the Pt and Pd adsorption process suit well the pseudo-second-order kinetics model. Fungi Aspergillus sp. shows higher adsorption capacity for both metals than yeast Saccharomyces sp. The maximum adsorption capacity of fungi was 5.49 mg g−1 for Pt(IV) and 4.28 mg g−1 for Pd(II). The fungi possess the ability for efficient removal of studied ions from different wastewater samples (sewage and road run-off water). It was also demonstrated, that quantitative recovery of Pd from industrial wastes could be obtained by biosorption using Aspergillus sp.
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