The antidepressant-like effect of Ocimum basilicum in an animal model of depression

We investigated the efficacy of Ocimum basilicum (OB) essential oils for treating depression related behavioral, biochemical and histopathological changes caused by exposure to chronic unpredictable mild stress (CUMS) in mice and to explore the mechanism underlying the pathology. Male albino mice were divided into four groups: controls; CUMS; CUMS plus fluoxetine, the antidepressant administered for pharmacological validation of OB; and CUMS plus OB. Behavioral tests included the forced swim test (FST), elevated plus-maze (EPM) and the open ?eld test (OFT); these tests were performed at the end of the experiment. We assessed serum corticosterone level, protein, gene and immunoexpression of brain-derived neurotropic factor (BDNF) and glucocorticoid receptors (GRs) as well as immunoexpression of glial fibrillary acidic protein (GFAP), Ki67, caspase-3 in the hippocampus. CUMS caused depression in the mice as evidenced by prolonged immobility in the FST, prolonged time spent in the open arms during the EPM test and reduction of open field activity in the OFT. OB ameliorated the CUMS induced depressive status. OB significantly reduced the corticosterone level and up-regulated protein and gene expressions of BDNF and GR. OB reduced CUMS induced hippocampal neuron atrophy and apoptosis, and increased the number of the astrocytes and new nerve cells. OB significantly increased GFAP-positive cells as well as BDNF and GR immunoexpression in the hippocampus.     

Tumor necrosis factor alpha induction in human monocytes

The present study was undertaken to assess the presence of tumor necrosis factor (TNF)-alpha mRNA and protein in circulating human blood monocytes and to study the TNF-alpha gene expression in human monocytes isolated by continuous Percoll gradient fractionation. The technique of RNA isolation directly from the blood samples was used to study TNF-alpha mRNA expression in circulating human blood leukocytes. It was shown that human blood leukocytes of healthy donors contained no presynthesized pool of TNF-alpha mRNA as well as no TNF-alpha protein. It was found that early pretreatment with cycloheximide interferes with TNF-alpha mRNA induction by Staphylococcus aureus.     

Productivity of forests in the Eurosiberian boreal region and their potential to act as a carbon sink –- a synthesis

Based on review and original data, this synthesis investigates carbon pools and fluxes of Siberian and European forests (600 and 300 million ha, respectively). We examine the productivity of ecosystems, expressed as positive rate when the amount of carbon in the ecosystem increases, while (following micrometeorological convention) downward fluxes from the atmosphere to the vegetation (NEE = Net Ecosystem Exchange) are expressed as negative numbers. Productivity parameters are Net Primary Productivity (NPP=whole plant growth), Net Ecosystem Productivity (NEP = CO₂ assimilation minus ecosystem respiration), and Net Biome Productivity (NBP = NEP minus carbon losses through disturbances bypassing respiration, e.g. by fire and logging). Based on chronosequence studies and national forestry statistics we estimate a low average NPP for boreal forests in Siberia: 123 gC m^–2 y^–1. This contrasts with a similar calculation for Europe which suggests a much higher average NPP of 460 gC m^–2 y^–1 for the forests there. Despite a smaller area, European forests have a higher total NPP than Siberia (1.2–1.6 vs. 0.6–0.9 × 10¹⁵ gC region^–1 y^–1). This arises as a consequence of differences in growing season length, climate and nutrition. For a chronosequence of Pinus sylvestris stands studied in central Siberia during summer, NEE was most negative in a 67-y old stand regenerating after fire (– 192 mmol m^–2 d^–1) which is close to NEE in a cultivated forest of Germany (– 210 mmol m^–2 d^–1). Considerable net ecosystem CO₂-uptake was also measured in Siberia in 200- and 215-y old stands (NEE:174 and – 63 mmol m^–2 d^–1) while NEP of 7- and 13-y old logging areas were close to the ecosystem compensation point. Two Siberian bogs and a bog in European Russia were also significant carbon sinks (– 102 to – 104 mmol m^–2 d^–1). Integrated over a growing season (June to September) we measured a total growing season NEE of – 14 mol m^–2 summer^–1 (– 168 gC m^–2 summer^–1) in a 200-y Siberian pine stand and – 5 mol m^–2 summer^–1 (– 60 gC m^–2 summer^–1) in Siberian and European Russian bogs. By contrast, over the same period, a spruce forest in European Russia was a carbon source to the atmosphere of (NEE: + 7 mol m^–2 summer^–1 = + 84 gC m^–2 summer^–1). Two years after a windthrow in European Russia, with all trees being uplifted and few successional species, lost 16 mol C m^–2 to the atmosphere over a 3-month in summer, compared to the cumulative NEE over a growing season in a German forest of – 15.5 mol m^–2 summer^–1 (– 186 gC m^–2 summer^–1; European flux network annual averaged – 205 gC m^–2 y^–1). Differences in CO₂-exchange rates coincided with differences in the Bowen ratio, with logging areas partitioning most incoming radiation into sensible heat whereas bogs partitioned most into evaporation (latent heat). Effects of these different surface energy exchanges on local climate (convective storms and fires) and comparisons with the Canadian BOREAS experiment are discussed. Following a classification of disturbances and their effects on ecosystem carbon balances, fire and logging are discussed as the main processes causing carbon losses that bypass heterotrophic respiration in Siberia. Following two approaches, NBP was estimated to be only about 13–16 mmol m^–2 y^–1 for Siberia. It may reach 67 mmol m^–2 y^–1 in North America, and about 140–400 mmol m^–2 y^–1 in Scandinavia. We conclude that fire speeds up the carbon cycle, but that it results also in long-term carbon sequestration by charcoal formation. For at least 14 years after logging, regrowth forests remain net sources of CO₂ to the atmosphere. This has important implications regarding the effects of Siberian forest management on atmospheric concentrations. For many years after logging has taken place, regrowth forests remain weaker sinks for atmospheric CO₂ than are nearby old-growth forests.     

Using wintergreen oil for mounting mosquito larvae: a safer alternative to xylene

Permanent mounting of fourth instar mosquito larvae is essential for identifying Aedes spp. This procedure requires extensive exposure to xylene, a clearing agent in the mounting process. We investigated wintergreen oil as a substitute for xylene. Five hundred larvae were mounted on slides to evaluate shrinkage or expansion of specimens after clearing using xylene or wintergreen oil. We examined the ventral brush and siphonal hair tufts for species identification and for preservation of morphological characteristics after clearing specimens in xylene or wintergreen oil. Shrinkage of the length of whole larvae and width of the head, thorax and abdomen after mounting was significantly greater after clearing with xylene than with wintergreen oil. The length of the comb scale nearest the ventral brush was similar for both clearing agents. The clarity of the specimens after mounting was improved by clearing with wintergreen oil, but the integrity of the ventral brush and siphonal hair tufts were similar for both clearing agents.     

Neutrophil alpha-defensin human neutrophil peptide modulates cytokine production in human monocytes and adhesion molecule expression in endothelial cells

Defensins, a family of small, cationic, antimicrobial peptides, are found in mammals, insects and plants. alpha-defensins are stored in granules of neutrophils and released upon activation by exocytosis. It was shown here that human neutrophil peptide (HNP), at concentrations of 10(-8) -10(-9) M, up-regulated the expression of TNF-alpha and IL-1 beta in monocytes activated with Staphylococcus aureus or PMA, while expression of IL-10 mRNA was down-regulated and production of IL-8 was not affected. HNP alone was unable to induce TNF-alpha or IL-1 beta expression in resting monocytes. At concentrations of 10(-4) -10(-5)M, HNP was cytotoxic for monocytes in serum-free medium. The cytotoxicity was abrogated in the presence of serum, while a cytokine-modulating effect of HNP was observed in the presence of serum and in whole blood, suggesting that this mechanism may function in vivo. Similarly, serum did not abrogate bactericidal activity of HNP. It was also demonstrated herein that HNP at 10 (-8) -10(-9) M, attenuated the inhibitory action of dexamethasone on TNF-alpha production. In parallel to monocyte studies, we have showed that HNP at concentrations ranging from 10(-9)M to 10(-6)M caused about 5-fold suppression of VCAM-1 expression in TNF-alpha-activated human umbilical vein endothelial cells, while the ICAM-1 expression was not affected. Our findings suggest that neutrophil defensins have the potential to modulate the inflammatory responses through regulation of cytokine production and adhesion molecule expression.     

Expression of IL-8 gene in human monocytes and lymphocytes: differential regulation by TNF and IL-1

TNF-alpha and IL-1 were reported to be the most powerful inducers of IL-8 in a multitude of cells, including leukocytes. In this study, we investigated TNF-alpha- and IL-1-mediated regulation of IL-8 gene expression in non-fractionated PBMC, and purified monocyte (MO) and lymphocyte (LY) fractions. Our analysis revealed that purified human MO did not respond to exogenous TNF-alpha with the induction of IL-8 mRNA or protein, nor require endogenous TNF-alpha for IL-8 expression. In contrast, in the presence of exogenous IL-1alpha and IL-1beta a substantial enhancement of IL-8 mRNA and protein expression in MO was observed. Nevertheless, antibodies to IL-1alpha and IL-1beta were unable to downregulate the expression of IL-8 in resting adherent or Staphylococcus aureus Cowan 1 (SAC)-stimulated MO. In contrast with MO, purified LY and non-fractionated PBMC expressed IL-8 in response to exogenous TNF-alpha, similar to exogenous IL-1alpha and IL-1beta. As was seen with MO, antibodies to TNF-alpha, IL-1alpha and IL-1beta did not inhibit the expression of IL-8 in purified LY and non-fractionated PBMC stimulated with SAC and LPS. Taken together, our data demonstrate major differences in responsiveness of MO and LY to exogenous TNF-alpha and IL-1, and suggest relative autonomy of IL-8 gene expression in these cells that does not require accessory cytokines but can be induced directly by exogenous stimuli.     

Role of Serine Proteases in the Regulation of Interleukin-877 during the Development of Bronchopulmonary Dysplasia in Preterm Ventilated Infants

Rationale

The chemokine interleukin-8 is implicated in the development of bronchopulmonary dysplasia in preterm infants. The 77-amino acid isoform of interleukin-8 (interleukin-8₇₇) is a less potent chemoattractant than other shorter isoforms. Although interleukin-8₇₇ is abundant in the preterm circulation, its regulation in the preterm lung is unknown.

Objectives

To study expression and processing of pulmonary interleukin-8₇₇ in preterm infants who did and did not develop bronchopulmonary dysplasia.

Methods

Total interleukin-8 and interleukin-8₇₇ were measured in bronchoalveolar lavage fluid from preterm infants by immunoassay. Neutrophil serine proteases were used to assess processing. Neutrophil chemotaxis assays and degranulation of neutrophil matrix metalloproteinase-9 were used to assess interleukin-8 function.

Main Results

Peak total interleukin-8 and interleukin-8₇₇ concentrations were increased in infants who developed bronchopulmonary dysplasia compared to those who did not. Shorter forms of interleukin-8 predominated in the preterm lung (96.3% No-bronchopulmonary dysplasia vs 97.1% bronchopulmonary dysplasia, p>0.05). Preterm bronchoalveolar lavage fluid significantly converted exogenously added interleukin-8₇₇ to shorter isoforms (p<0.001). Conversion was greater in bronchopulmonary dysplasia infants (p<0.05). This conversion was inhibited by α-1 antitrypsin and antithrombin III (p<0.01). Purified neutrophil serine proteases efficiently converted interleukin-8₇₇ to shorter isoforms in a time- and dose-dependent fashion; shorter interleukin-8 isoforms were primarily responsible for neutrophil chemotaxis (p<0.001). Conversion by proteinase-3 resulted in significantly increased interleukin-8 activity in vitro (p<0.01).

Conclusions

Shorter, potent, isoforms interleukin-8 predominate in the preterm lung, and are increased in infants developing bronchopulmonary dysplasia, due to conversion of interleukin-8₇₇ by neutrophil serine proteases and thrombin. Processing of interleukin-8 provides an attractive therapeutic target to prevent development of bronchopulmonary dysplasia.