Semisynthetic Triterpenes Derived from Euphorbia officinarum as Plant Growth Promoters and Inducers of Disease Resistance

This study evaluated the effect of application of the semisynthetic triterpenes 3β-acetoxy-norlup-20-one (F4) and 3-chloro-4α,14α-dimethyl-5α-cholest-8-ene (F6) triterpene derivatives from Euphorbia officinarum on the growth of tomato seedlings under normal conditions and when challenged with the pathogens Verticillium dahliae and Agrobacterium tumefaciens. Foliar spray of F4 and F6 significantly improved growth rate, fresh weight, dry weight, and leaf area. In addition, they enhanced several physiological parameters including photosynthetic pigments, proline content, and nitrate reductase activity. Moreover, they induced H₂O₂ accumulation and increased the activity of several antioxidant enzymes such as catalase, ascorbate peroxidase, and guaiacol peroxidase. They also enhanced disease resistance against V. dahliae and A. tumefaciens. These results suggest that the two semisynthetic triterpenes represent new plant growth regulators and inducers of plant disease resistance.

     

Hypoxia/reoxygenation and vitamin C intake influence NO synthesis and antioxidant defenses of neutrophils

Oxidative stress induced by hypoxia/reoxygenation mediates the pathophysiological consequence of ischemia/reperfusion and human diseases. Diving apnea could be a good model of oxidative stress induced by hypoxia/reoxygenation. We studied the influence of vitamin C diet supplementation on the response of neutrophil antioxidant defenses, NO production, and redox status to diving apnea. Seven professional apnea divers participated in a double-blind cross study. Divers were assigned to either vitamin C-supplemented (1 g/d for a week) or placebo groups. Blood samples were taken under basal conditions, immediately after diving apnea for 4 h and after 1 h of recovery. Plasma vitamin C increased only in the supplemented group after diving and was maintained high in recovery. Diving apnea decreased neutrophil GSH/GSSG ratio in both groups, but maintained protein carbonyl derivates. Neutrophil catalase activity and levels and glutathione peroxidase activity were lower in the supplemented group than in the placebo group after diving. iNOS and nitrite levels decreased only in the supplemented group after diving and recovery. Diving apnea induced oxidative stress and initiated neutrophil reactions that resemble the acute-phase immune response with increased myeloperoxidase activity in neutrophils. Diet supplementation with vitamin C reduced neutrophil iNOS levels and NO production.     

Large-volume sample stacking-capillary electrophoresis used for the determination of 3-nitrotyrosine in rat urine

Large-volume sample stacking using the electroosmotic flow (EOF) pump technique has been investigated for the quantification of 3-nitrotyrosine in urine of diabetic rats. The best separation conditions for these highly complex samples were obtained using capillary electrophoresis (CE) in the reversed polarity mode (i.e., injecting at the cathode and detecting at the anode) using cetyltrimethylammonium bromide (CTAB) in the running buffer. The optimum CE separation conditions were achieved using a phosphate buffer prepared with 0.15M phosphoric acid and 0.5 mM CTAB adjusted to pH 6.4 with sodium hydroxide. In such CE conditions, the limit of detection (LOD) was 1.77 microM for 3-nitrotyrosine with normal injection mode, meanwhile with the large-volume sample stacking technique a more than 20-fold improvement was observed (i.e., LOD = 0.08 microM was obtained) without noticeable loss of resolution. This value allowed the detection of 3-nitrotyrosine in urine from diabetic rats. To our knowledge, this work is one of the few applications showing the great possibilities of these stacking procedures to analyse biological samples by CE.     

Determination of protein markers in human serum: Analysis of protein expression in toxic oil syndrome studies

Toxic oil syndrome (TOS) is a disease that appeared in Spain in 1981. It affected more than 20 000 people and produced over 300 deaths in the first 2 years. In this paper, a prospective study on the differences in gene expression in sera between a control versus a TOS-affected population, both originally exposed to the toxic oil, is presented. Differential protein expression was analyzed by two-dimensional electrophoresis (2-DE). Several problems related with serum analysis by 2-DE were addressed in order to improve protein detection in the gel images. Three new commercial systems for albumin depletion were tested to optimize the detection of minor proteins that can be obscured by the presence of a few families of high abundance proteins (albumin, immunoglobulins). Other factors, such as the use of nonionic reductants or the presence of thiourea in the gels, were also tested. From these optimized images, a group of 329 major gel spots was located, matched and compared in serum samples. Thirty-five of these protein spots were found to be under- or overexpressed in TOS patients (> three-fold increase or decrease). Proteins in the differential spots were identified by matrix-assisted laser desorption/ionization-time of flight peptide map fingerprinting and database search. Several haptoglobin isoforms were found to be differentially expressed, showing expression phenotypes that could be related with TOS affection. Haptoglobin phenotypes have been previously reported to have important biological and clinical consequences and have been described as risk factors for several diseases.     

20-HETE inotropic effects involve the activation of a nonselective cationic current in airway smooth muscle

20-Hydroxyeicosatetraenoic acid (20-HETE) controls several mechanisms such as vasoactivity, mitogenicity, and ion transport in various tissues. Our goal was to quantify the effects of 20-HETE on the electrophysiological properties of airway smooth muscle (ASM). Isometric tension measurements, performed on guinea pig ASM, showed that 20-HETE induced a dose-dependent inotropic effect with an EC50 value of 1.5 microM. This inotropic response was insensitive to GF-109203X, a PKC inhibitor. The sustained contraction, requiring Ca2+ entry, was partially blocked by either 100 microM Gd3+ or 1 microM nifedipine, revealing the involvement of noncapacitative Ca2+ entry and L-type Ca2+ channels, respectively. Microelectrode measurements showed that 3 microM 20-HETE depolarized the membrane potential in guinea pig ASM by 13 +/- 2mV(n = 7), as did 30 microM 1-oleoyl-2-acetyl-sn-glycerol. Depolarizing effects were also observed in the absence of epithelium. Patch-clamp recordings demonstrated that 1 microM 20-HETE activated a nonselective cationic inward current that may be supported by the activation of transient receptor potential channels. The presence of canonical transient receptor potential mRNA was confirmed by RT-PCR in guinea pig ASM cells.     

Fine needle aspiration cytology of neurothekeoma. A case report

BACKGROUND: Neurothekeoma (NT) is a rare, benign neoplasm of soft parts with a distinctive histologic appearance. To our knowledge, the cytologic findings have not been described before. We present a case of NT with the cytologic features on fine needle aspiration cytology (FNAC). CASE: A 54-year-old female presented with a circumscribed nodule in the left breast. The lesion was evaluated by FNAC. The smears showed an abundant, metachromatic, myxoid matrix with fusiform and epithelioid cells, some binucleated or multinucleated, loose or in groups and sometimes forming concentric whorls. The lesion was removed, and the diagnosis of NT was made after histopathologic study. CONCLUSION: NT is an extremely rare neoplasm in the mammary region. Fusiform and epithelioid cells arranged in concentric whorls in a myxoid tumor of soft tissue are a distinctive characteristic of this neoplasm and can suggest the diagnosis.