The role of seasonality on the inhibitory effect of Brazilian green propolis on the oxidative metabolism of neutrophils

The reactive oxygen species (ROS) produced by neutrophils are involved in the pathogenesis of several diseases, for which the intake of antioxidants could benefit patients either as a prophylactic or therapeutic treatment. Propolis is among the known antioxidants, and its chemical composition may vary under the influence of seasonality, which may interfere in its biological properties. This work evaluates the role of seasonality on the production of some important compounds of propolis samples produced monthly from November 2001 through October 2002 as well as the effect of these samples on the oxidative metabolism of stimulated neutrophils, by using both luminol and lucigenin to produce chemiluminescence (CLlum and CLluc, respectively). The cytotoxicity of the most active extracts to neutrophils was also investigated. The inhibitory effect of the propolis samples varied significantly during the studied period for both assays (3.4 +/- 1.1 to 16.0 +/- 1.1 mu g/mL for CLlum and 6.2 +/- 2.0 to 30.0 +/- 5.0 mu g/mL for CLluc), which was also observed in the quantitative profile of the main analyzed compounds (aromadendrin-4`-methyl ether, artepillin C, and baccharin). This effect started to become more prominent during the fall and, among all the studied extracts, the one obtained in May displayed the highest inhibitory effect on CL production (3.4 +/- 1.1 mu g/mL for alum and 6.2 +/- 2.0 mu g/mL for CLluc). The HPLC qualitative profiles of the extracts of propolis samples were quite similar, but there was a huge variation in terms of quantitative profile. It seems that aromadendrin-4`-methyl ether and baccharin play an essential role in the antioxidant activity, while artepillin C is not very important for this effect. The extracts presenting the highest antioxidant activity were produced in May, June, and August, and they did not display cytotoxicity at 25 mu g/mL; quercetin, used as control, was not toxic to neutrophils at 8.5 mu g/mL (C) 2010 Elsevier B.V. All rights reserved.

Phosphatidylinositol phospholipase C mediates carbon sensing and vegetative nuclear duplication rates in Aspergillus nidulans

In this work, we disrupted one of three putative phosphatidylinositol phospholipase C genes of Aspergillus nidulans and studied its effect on carbon source sensing linked to vegetative mitotic nuclear division. We showed that glucose does not affect nuclear division rates during early vegetative conidial germination (6-7 h) in either the wild type or the plcA-deficient mutant. Only after 8 h of cultivation on glucose did the mutant strain present some decrease in nuclear duplication. However, decreased nuclear division rates were observed in the wild type when cultivated in media amended with polypectate, whereas our plcA-deficient mutant did not show slow nuclear duplication rates when grown on this carbon source, even though it requires induction and secretion of multiple pectinolytic enzymes to be metabolized. Thus, plcA appears to be directly linked to high-molecular-weight carbon source sensing.

Reduction of enantioselectivity in the kinetic disposition and metabolism of verapamil in rats exposed to toluene

Toluene and verapamil are subject to extensive oxidative metabolism mediated by CYP enzymes, and their interaction can be stereoselective. In the present study we investigated the influence of toluene inhalation on the enantioselective kinetic disposition of verapamil and its metabolite, norverapamil, in rats. Male Wistar rats (n = 6 per group) received a single dose of racemic verapamil (10 mg/kg) orally at the fifth day of nose-only toluene or air (control group) inhalation for 6 h/day (25, 50, and 100 ppm). Serial blood samples were collected from the tail up to 6 h after verapamil administration. The plasma concentrations of verapamil and norverapamil enantiomers were analyzed by LC-MS/MS by using a Chiralpak AD column. Toluene inhalation did not influence the kinetic disposition of verapamil or norverapamil enantiomers (p > 0.05, Kruskal-Wallis test) in rats. The pharmacokinetics of verapamil was enantioselective in the control group, with a higher plasma proportion of the S-verapamil (AUC 250.8 versus 120.4 ng.h.mL(-1); p <= 0.05, Wilcoxon test) and S-norverapamil (AUC 72.3 versus 52.3 ng.h.mL(-1); p <= 0.05, Wilcoxon test). Nose-only exposure to toluene at 25, 50, or 100 ppm resulted in a lack of enantioselectivity for both verapamil and norverapamil. The study demonstrates the importance of the application of enantioselective methods in studies on the interaction between solvents and chiral drugs.

The effects of dietary supplementation of methionine on genomic stability and p53 gene promoter methylation in rats

Methionine is a component of one-carbon metabolism and a precursor of S-adenosylmethionine (SAM), the methyl donor for DNA methylation. When methionine intake is high, an increase of S-adenosylmethionine (SAM) is expected. DNA methyltransferases convert SAM to S-adenosylhomocysteine (SAH). A high intracellular SAH concentration could inhibit the activity of DNA methyltransferases. Therefore, high methionine ingestion could induce DNA damage and change the methylation pattern of tumor suppressor genes. This study investigated the genotoxicity of a methionine-supplemented diet. It also investigated the diet`s effects on glutathione levels, SAM and SAH concentrations and the gene methylation pattern of p53. Wistar rats received either a methionine-supplemented diet (2% methionine) or a control diet (0.3% methionine) for six weeks. The methionine-supplemented diet was neither genotoxic nor antigenotoxic to kidney cells, as assessed by the comet assay. However, the methionine-supplemented diet restored the renal glutathione depletion induced by doxorubicin. This fact may be explained by the transsulfuration pathway, which converts methionine to glutathione in the kidney. Methionine supplementation increased the renal concentration of SAH without changing the SAM/SAH ratio. This unchanged profile was also observed for DNA methylation at the promoter region of the p53 gene. Further studies are necessary to elucidate this diet`s effects on genomic stability and DNA methylation. (C) 2011 Elsevier ay. All rights reserved.

Influence of N-Hexane Inhalation on the Enantioselective Pharmacokinetics and Metabolism of Verapamil in Rats

Verapamil (VER) is commercialized as a racemic mixture of the (+)-(R)-VER and (-)-(S)-VER enantiomers. VER is biotransformed into norverapamil (NOR) and other metabolites through CYP-dependent pathways. N-hexane is a solvent that can alter the metabolism of CYP-dependent drugs. The present study investigated the influence of n-hexane (nose-only inhalation exposure chamber at concentrations of 88, 176, and 352 mg/m(3)) on the kinetic disposition of the (+)-(R)-VER, (-)-(S)-VER, (R)-NOR and (S)-NOR in rats treated with a single dose of racemic VER (10 mg/kg). VER and NOR enantiomers in rat plasma was analyzed by LC-MS/MS (m/z = 441.3 > 165.5 for the NOR and m/z 455.3 > 165.5 for the VER enantiomers) using a Chiralpak (R) AD column. Pharmacokinetic analysis was performed using a monocompartmental model. The pharmacokinetics of VER was enantioselective in control rats, with higher plasma proportions of the (-)-(S)-VER eutomer (AUC(0-infinity) = 250.8 vs. 120.4 ng/ml/h; P <= 0.05, Wilcoxon test). The (S)-NOR metabolite was also found to accumulate in plasma of control animals, with an S/R AUC(0-infinity) ratio of 1.5. The pharmacokinetic parameters AUC(0-infinity), Cl/F, Vd/F, and t(1/2) obtained for VER and NOR enantiomers were not altered by nose-only exposure to n-hexane at concentrations of 88, 176, or 352 mg/m(3) (P > 0.05, Kruskal-Wallis test). However, the verapamil kinetic disposition was not enantioselective for the animals exposed to n-hexane at concentrations equal to or higher than the TLV-TWA. This finding is relevant considering that the (-)-(S)-VER eutomer is 10-20 times more potent than R-(+)-VER in terms of its chronotropic effect on atrioventricular conduction in rats and humans. Chirality 22:29-34, 2010. (C) 2009 Wiley-Liss, Inc.

Influence of gestational diabetes mellitus on the stereoselective kinetic disposition and metabolism of labetalol in hypertensive patients

Purpose This study investigated the influence of gestational diabetes mellitus on the kinetic disposition and stereoselective metabolism of labetalol administered intravenously or orally. Methods Thirty hypertensive women during the last trimester of pregnancy were divided into four groups: non-diabetic and diabetic women treated with intravenous or oral labetalol. Results The pharmacokinetics of labetalol was not stereoselective in diabetic or non-diabetic pregnant women receiving the drug intravenously. However, oral administration of labetalol resulted in lower values of the area under the plasma concentration versus time curve (AUC) for the beta-blocker (RR) than for the other enantiomers in both diabetic and non-diabetic women. Gestational diabetes mellitus caused changes in the kinetic disposition of the labetalol stereoisomers when administered orally. The AUC values for the less potent adrenoceptor antagonist (SS) and for the alpha-blocking (SR) isomers were higher in diabetic than in non-diabetic pregnant women. Conclusions The approximately 100% higher AUC values obtained for the (SR) isomer in diabetic pregnant women treated with oral labetalol may be of clinical relevance in terms of the alpha-blocking activity of this isomer.

Autoimmune Neurological Disease

This book provides a comprehensive and critical overview of the immunological aspects of autoimmune neurological disease. These diseases include common conditions such as multiple sclerosis, the Guillain–Barré syndrome and myasthenia gravis. The introductory chapters on antigen recognition and self–non-self discrimination, and on neuroimmunology, are followed by chapters on specific diseases. These are presented in a standardized format with sections on clinical features, genetics, neuropathology, pathophysiology, immunology and therapy. Each chapter has a concluding section which summarizes key points and suggests directions for future research. Animal models of autoimmune neurological disease are also covered in detail because of their importance in understanding the human diseases. The book is suitable for clinicians and neurologists managing patients with these diseases, and for immunologists, neuroscientists and neurologists investigating the pathogenesis and pathophysiology of these disorders.

Immunology of multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) leading to demyelination, axonal damage, and progressive neurologic disability. The development of MS is influenced by environmental factors, particularly the Epstein-Barr virus (EBV), and genetic factors, which include specific HLA types, particularly DRB1*1501-DQA1*0102-DQB1*0602, and a predisposition to autoimmunity in general. MS patients have increased circulating T-cell and antibody reactivity to myelin proteins and gangliosides. It is proposed that the role of EBV is to infect autoreactive B cells that then seed the CNS and promote the survival of autoreactive T cells there. It is also proposed that the clinical attacks of relapsing-remitting MS are orchestrated by myelin-reactive T cells entering the white matter of the CNS from the blood, and that the progressive disability in primary and secondary progressive MS is caused by the action of autoantibodies produced in the CNS by ­meningeal lymphoid follicles with germinal centers.

Genetics and race variability of the lucerne - Colletotrichum trifolii pathosystem in Australia

The Australian-bred lucerne cultivars, Trifecta and Sequel, were found to possess useful levels of resistance to both Colletotrichum trifolii races 1 and 2. Race 2 has only been previously observed in the United States and surveys did not reveal its presence in Australia. Multilocus fingerprinting using random amplified polymorphic DNA (RAPDs) analysis revealed low diversity (<10% dissimilarity) within Australian C. trifolii collections, and between the Australian race 1 isolates and a US race 2 isolate. Studies on the inheritance of resistance to C. trifolii race 1 in individual clones from Trifecta and Sequel revealed the presence of 2 different genetic mechanisms. One inheritance was for resistance as a recessive trait, and the other indicated that resistance was dominant. The recessive system has never been previously reported, whereas in the US, 2 completely dominant and independent tetrasomic genes Anl and Ant have been reported to condition C. trifolii resistance. It was not possible to fit the observed segregations from our studies to a single-gene model. In contrast to US studies, clones of cv. Sequel exhibiting the recessive resistance reacted differently to spray and stem injection with C. trifolii inoculum, being resistant to the former and susceptible to the latter, providing additional evidence for the presence of a different genetic mechanism conditioning resistance to those previously reported in the US. As C. trifolii is one of the most serious diseases of lucerne worldwide, the future development of molecular markers closely linked to the dominant and recessive resistances identified in these studies, and the relationships between these resistances and Anl and Ans as determined by genetic mapping, appear to be useful areas of future study.

TFEC is a macrophage-restricted member of the microphthalmia-TFE subfamily of basic helix-loop-helix leucine zipper transcription factors

The murine homologue of the TFEC was cloned as part of an analysis of the expression of the microphthalmia-TFE (MiT) subfamily of transcription factors in macrophages. TFEC, which most likely acts as a transcriptional repressor in heterodimers with other MiT family members, was identified in cells of the mononuclear phagocyte lineage, coexpressed,vith all other known MiT subfamily members (Mitf, TFE3, TFEB), Northern blot analysis of several different cell lineages indicated that the expression of murine TFEC (mTFEC) was restricted to macrophages. A 600-bp fragment of the TATA-less putative proximal promoter of TFEC shares features with many known macrophage-specific promoters and preferentially directs luciferase expression in the RAW264.7 macrophage cell line in transient transfection assays. Five of six putative Ets motifs identified in the TFEC promoter bind the macrophage-restricted transcription factor PU,I under in vitro conditions and in transfected 3T3 fibroblasts; the minimal luciferase activity of the TFEC promoter could be induced by coexpression of PU.1 or the related transcription factor Ets-2. The functional importance of the tissue-restricted expression of TFEC and a possible role in macrophage-specific gene regulation require further investigation, but are likely to be linked to the role of the other MiT family members in this lineage.

Glycine metabolism by plant roots and its occurrence in Australian plant communities

Soluble organic nitrogen, including protein and amino acids, was found to be a ubiquitous form of soil N in diverse Australian environments. Fine roots of species representative of these environments were found to be active in the metabolism of glycine. The ability to incorporate [N-15]glycine was widespread among plant species from subantarctic to tropical communities. In species from subantarctic herbfield, subtropical coral cay, subtropical rainforest and wet heathland, [N-15]glycine incorporation ranged from 26 to 45% of (NH4+)-N-15 incorporation and was 2- to 3-fold greater than (NO3-)-N-15 incorporation. Most semiarid mulga and tropical savanna woodland species incorporated [N-15]glycine and (NO3-)-N-15 in similar amounts, 18-26% of (NH4+)-N-15 incorporation. We conclude that the potential to utilise amino acids as N sources is of widespread occurrence in plant communities and is not restricted to those from low temperature regimes or where N mineralisation is limited. Seedlings of Hakea (Proteaceae) were shown to metabolise glycine, with a rapid transfer of N-15 from glycine to serine and other amino compounds. The ability to take up and metabolise glycine was unaffected by the presence of equimolar concentrations of NO3- and NH4+. Isonicotinic acid hydrazide (INH) did not inhibit the transfer of N-15-label from glycine to serine indicating that serine hydroxymethyltransferase was not active in glycine catabolism. In contrast aminooxyacetate (AOA) strongly inhibited transfer of N-15 from glycine to serine and labelling of other amino compounds, suggesting that glycine is metabolised in roots and cluster roots of Hakea via an aminotransferase.

Complement-mediated regulation of Trichomonas vaginalis infection in mice

Trichomonas vaginalis is a flagellated protozoan which causes trichomoniasis, a sexually transmitted disease of the human genitourinary tract, The importance of the alternative complement pathway in host defence against T. vaginalis was investigated in vitro. Kinetic studies utilising immunofixation following electrophoresis showed that both a strongly and weakly virulent strain of T, vaginalis activated murine serum C3. In vivo studies with congenic-resistant, C5-deficient, B10.D2/OSn- and C5-sufficient, B10.D2/nSn mice showed that the presence of C5 is a significant factor in the innate host resistance to primary infection with a strongly virulent, but not a weakly virulent trichomonad strain.

Molecular immunology databases and data repositories

Over recent years databases have become an extremely important resource for biomedical research. Immunology research is increasingly dependent on access to extensive biological databases to extract existing information, plan experiments, and analyse experimental results. This review describes 15 immunological databases that have appeared over the last 30 years. In addition, important issues regarding database design and the potential for misuse of information contained within these databases are discussed. Access pointers are provided for the major immunological databases and also for a number of other immunological resources accessible over the World Wide Web (WWW). (C) 2000 Elsevier Science B.V. All rights reserved.