Effects of Chronic Restraint Stress and 17-β-Estradiol Replacement on Oxidative Stress in the Spinal Cord of Ovariectomized Female Rats

Previous studies have shown sex-specific oxidative changes in spinal cord of rats submitted to chronic stress, which may be due to gonadal hormones. Here, we assessed total radical-trapping potential (TRAP), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and lipid peroxidation (evaluated by the TBARS test) in the spinal cord of ovariectomized (OVX) female rats. Female rats were subjected to OVX, and half of the animals received estradiol replacement. Animals were subdivided into controls and chronically stressed (for 40 days). Our findings demonstrate that chronic stress decreased TRAP, and increased SOD activity in spinal cord homogenates from ovariectomized female rats and had no effect on GPx activity. On the other hand, groups receiving 17β-estradiol replacement presented a decreased GPx activity, but no alteration in TRAP and in SOD activity. No differences in the TBARS test were found in any of the groups analyzed. In conclusion, our results support the idea that chronic stress induces an imbalance between SOD and GPx activities, additionally decreasing TRAP. Estradiol replacement did not reverse the effects of chronic stress, but induced a decrease in GPx activity. Therefore, estradiol replacement in ovariectomized chronically stressed rats could make the spinal cord more susceptible to oxidative injury.     

Low and high-dose intradermal infection with Leishmania major and Leishmania amazonensis in C57BL/6 mice

A model of skin infection with Leishmania amazonensis with low doses of parasites is compared to infection with high doses of L. amazonensis and low and high doses of Leishmania major. C57BL/6 mice were infected with 103 or 10(6) parasites in the ear and the outcome of infection was assessed. The appearance of lesions in mice infected with 103 parasites was delayed compared to mice infected with 10(6) Leishmania and parasites were detectable at the infection site before lesions became apparent. Mice infected with L. amazonensis displayed persistent lesions, whereas infection with L. major spontaneously healed in all groups, although lymphocytes persisted at the site of infection after healing. Macrophages persisted only in L. amazonensis-infected mice. High-dose L. amazonensis-infected mice produced lower levels of IFN-γ and TNF than mice infected with L. major. No correlation between the persistence of parasites and IL-10 levels and the production of nitric oxide or urea by macrophages was found. We conclude that infection with low doses of L. amazonensis in the dermis changes the course of infection by delaying the appearance of lesions. However, low-dose infection does not change the outcomes of susceptibility and cytokine production described for subcutaneous infection with high numbers of parasites.     

Synthesis and pharmacological evaluation of pyrazine N-acylhydrazone derivatives designed as novel analgesic and anti-inflammatory drug candidates

In this paper, we report the synthesis and pharmacological evaluation of pyrazine N-acylhydrazone (NAH) derivatives (2a–s) designed as novel analgesic and anti-inflammatory drug candidates. This series was planned by molecular simplification of prototype 1 (LASSBio-1018), previously described as a non-selective cyclooxygenase inhibitor. Derivatives 2a–s were evaluated in several animal models of pain and inflammation, standing-out compound 2o (2-N′-[(E)-(3,4,5-trimethoxyphenyl) methylidene]-2-pyrazinecarbohydrazide; LASSBio-1181), that was also active in a murine model of chronic inflammation (i.e., adjuvant-induced arthritis test in rats) and can be considered a new analgesic and anti-inflammatory lead for drug development.     

Chemical constituents of Papulaspora immersa, an endophyte from Smallanthus sonchifolius (Asteraceae), and their cytotoxic activity

Papulaspora immersa H. H. Hotson was isolated from roots and leaves of Smallanthus sonchifolius (Poepp. and Endl. ) H. Rob. (Asteraceae), traditionally known as Yacon. The fungus was cultured in rice, and, from the AcOEt fraction, 14 compounds were isolated. Among them, (22E,24R)‐8,14‐epoxyergosta‐4,22‐diene‐3,6‐dione ( 4 ), 2,3‐epoxy‐1,2,3,4‐tetrahydronaphthalene‐c‐1,c‐4,8‐triol ( 10 ), and the chromone papulasporin ( 13 ) were new secondary metabolites. The spectral data of the known natural products were compared with the literature data, and their structures were established as the (24R)‐stigmast‐4‐en‐3‐one ( 1 ), 24‐methylenecycloartan‐3β‐ol ( 2 ), (22E,24R)‐ergosta‐4,6,8(14),22‐tetraen‐3‐one ( 3 ), (?)‐(3R,4R)‐4‐hydroxymellein ( 5 ), (?)‐(3R)‐5‐hydroxymellein ( 6 ), 6,8‐dihydroxy‐3‐methylisocoumarin ( 7 ), (?)‐(4S)‐4,8‐dihydroxy‐α‐tetralone ( 8 ), naphthalene‐1,8‐diol ( 9 ), 6,7,8‐trihydroxy‐3‐methylisocoumarin ( 11 ), 7‐hydroxy‐2,5‐dimethylchromone ( 12 ), and tyrosol ( 14 ). Compound 4 showed the highest cytotoxic activity against the human tumor cell lines MDA‐MB435 (melanoma), HCT‐8 (colon), SF295 (glioblastoma), and HL‐60 (promyelocytic leukemia), with IC₅₀ values of 3.3, 14.7, 5.0 and 1.6 μM , respectively. Strong synergistic effects were also observed with compound 5 and some of the isolated steroidal compounds.     

Development and Evaluation of a Sensitive PCR-ELISA System for Detection of Schistosoma Infection in Feces

Background

A PCR-enzyme-linked immunosorbent assay (PCR-ELISA) was developed to overcome the need for sensitive techniques for the efficient diagnosis of Schistosoma infection in endemic settings with low parasitic burden.

Methodology/Principal Findings

This system amplifies a 121-base pair tandem repeat DNA sequence, immobilizes the resultant 5′ biotinylated product on streptavidin-coated strip-well microplates and uses anti-fluorescein antibodies conjugated to horseradish peroxidase to detect the hybridized fluorescein-labeled oligonucleotide probe. The detection limit of the Schistosoma PCR-ELISA system was determined to be 1.3 fg of S. mansoni genomic DNA (less than the amount found in a single cell) and estimated to be 0.15 S. mansoni eggs per gram of feces (fractions of an egg). The system showed good precision and genus specificity since the DNA target was found in seven Schistosoma DNA samples: S. mansoni, S. haematobium, S. bovis, S. intercalatum, S. japonicum, S. magrebowiei and S. rhodaini. By evaluating 206 patients living in an endemic area in Brazil, the prevalence of S. mansoni infection was determined to be 18% by examining 12 Kato-Katz slides (41.7 mg/smear, 500 mg total) of a single fecal sample from each person, while the Schistosoma PCR-ELISA identified a 30% rate of infection using 500-mg of the same fecal sample. When considering the Kato-Katz method as the reference test, artificial sensitivity and specificity rates of the PCR-ELISA system were 97.4% and 85.1%, respectively. The potential for estimating parasitic load by DNA detection in feces was assessed by comparing absorbance values and eggs per gram of feces, with a Spearman correlation coefficient of 0.700 (P<0.0001).

Conclusions/Significance

This study reports the development and field evaluation of a sensitive Schistosoma PCR-ELISA, a system that may serve as an alternative for diagnosing Schistosoma infection.     

Molecular typing of clinical and environmental Cryptococcus neoformans isolates in the Brazilian state Rio Grande do Sul

In Brazil, 4.5% of the AIDS-related opportunistic infections are caused by Cryptococcus neoformans. This pathogen is a ubiquitous environmental basidiomycetous encapsulated yeast, commonly found in soil and avian excreta. The present study investigates further the population structure of clinical and environmental C. neoformans isolates from south Brazil. One hundred five clinical and 19 environmental (pigeon excreta and Eucalyptus spp.) isolates from the Brazilian state Rio Grande do Sul were characterized based on morphological, biochemical, molecular and serological data. The majority of the clinical and environmental isolates analyzed belonged to C. neoformans var. grubii serotype A (89.5 and 52.6%, respectively), were mating type alpha (98.1 and 94.7%, respectively) and were phospholipase-positive (94.3 and 73.7%, respectively). PCR-fingerprinting with the microsatellite-specific primer M13 and the minisatellite-specific primer (GACA)(4) grouped the majority of the isolates into the molecular type VNI (89.5 of the clinical and 52.6% of the environmental isolates). Our results add considerable new information to the few available data on ecology, molecular biology and epidemiology of C. neoformans in the southern region of Brazil.     

Quinolinic acid stimulates synaptosomal glutamate release and inhibits glutamate uptake into astrocytes

Quinolinic acid (QA) is an endogenous neurotoxin involved in various neurological diseases, whose action seems to be exerted via glutamatergic receptors. However, the exact mechanism responsible for the neurotoxicity of QA is far from being understood. We have previously reported that QA inhibits vesicular glutamate uptake. In this work, investigating the effects of QA on the glutamatergic system from rat brain, we have demonstrated that QA (from 0.1 to 10mM) had no effect on synaptosomal L-[3H]glutamate uptake. The effect of QA on glutamate release in basal (physiological K+ concentration) or depolarized (40 mM KCl) conditions was evaluated. QA did not alter K+-stimulated glutamate release, but 5 and 10mM QA significantly increased basal glutamate release. The effect of dizolcipine (MK-801), a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptor on glutamate release was investigated. MK-801 (5 microM) did not alter glutamate release per se, but completely abolished the QA-induced glutamate release. NMDA (50 microM) also stimulated glutamate release, without altering QA-induced glutamate release, suggesting that QA effects were exerted via NMDA receptors. QA (5 and 10mM) decreased glutamate uptake into astrocyte cell cultures. Enhanced synaptosomal glutamate release, associated with inhibition of glutamate uptake into astrocytes induced by QA could contribute to increase extracellular glutamate concentrations which ultimately lead to overstimulation of the glutamatergic system. These data provide additional evidence that neurotoxicity of QA may be also related to disturbances on the glutamatergic transport system, which could result in the neurological manifestations observed when this organic acid accumulates in the brain.     

Physiological,epigenetic, and proteomic responses in Pfaffia glomerata growth in vitro under salt stress and 5-azacytidine

Protoplasma - Plants adjust their complex molecular, biochemical, and metabolic processes to overcome salt stress. Here, we investigated the proteomic and epigenetic alterations involved in the...     

Palladium(II) complexes of 2-benzoylpyridine-derived thiosemicarbazones: spectral characterization, structural studies and cytotoxic activity

Palladium(II) complexes of 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N4-methyl (H2Bz4M) and N4-phenyl (H2Bz4Ph) derivatives were obtained and fully characterized. [Pd(2Bz4DH)Cl] (1) crystallizes in the monoclinic space group P21/c with a=11.671(1), b=10.405(1), c=13.124(1), beta=115.60(1) degrees and Z=4; [Pd(2Bz4M)Cl] (2) in the monoclinic space group P21/c with a=9.695(1), b=15.044(1), c=10.718(1) A, beta=105.38(1) degrees and Z=4 and [Pd(2Bz4Ph)Cl] (3) in the triclinic space group P1 with a=9.389(1), b=13.629(1), c=15.218(1) A, alpha=70.25(1), beta=73.46(1), gamma=83.57(1) degrees and two independent molecules per asymmetric unit (Z=4). All complexes show a quite similar planar fourfold environment around palladium(II). A negatively charged organic molecule acts as a tridentate ligand and binds to the metal through the pyridine nitrogen, the imine nitrogen and the sulfur atom. A chloride ion occupies the fourth coordination site. The planar complexes stack nearly parallel to one another in the lattice conforming a layered crystal structure. The cytotoxic activity of the thiosemicarbazones and their metal complexes was tested against the MCF-7, TK-10 and UACC-62 human tumor cell lines. The ligands exhibit lower values of GI50 and LC50 than the complexes, H2Bz4Ph being the most active with GI50<0.003 microM; LC50=13.4 microM; GI50=9.3 microM, LC50=12.9 microM; GI50<0.003, LC50=13.8 microM in the MCF-7, TK-10 and UACC-62 cell lines, respectively. Among the complexes, [Pd(2Bz4Ph)Cl] (3) exhibited the lowest values of GI50 in the three studied cell lines.