Lithium-induced decrease of brain inositol and increase of brain inositol-1-phosphate is transient

The effects of a single does of LiCl (2.5 or 10 mEq/kg) on brain inositol and inositol-1-phosphate (Ins1P), intermediates of brain phosphoinositude (PI) turnover, were determinated in male Han: Wistar rats. There was a remarkable, 36–58 fold elevation of brain Li⁺ as the single does of LiCl was increased 4-fold. Moreover, the accumulation of brain lithium was slow during repeated administration of LiCl. Brain lithium did not correlate with changes in brain PI turnover either after a single or repeated doses. Thus, after a single does of LiCl the increases in brain Ins1P were much less than the decreases in brain inositol. Also, brain inositol was significantly decreased only with the high dose of LiCl whereas brain Ins1P accumulation was more prominent with the lower dose. Moreover, repeated daily doses of LiCl only transiently increased brain Ins1P at 1 and 7 d whereas inositol remained at control levels throughout the 14 d observation period. Lithium probably caused the transient decrease in brain inositol by inhibiting several enzymes, in addition to the inhibition of myo-inositol mono-phosphates, in the PI cycle. Moreover, a slow dampening down of PI turnover by lithium, possible via an inhibitory action on G-protein-coupling, may also explain the present findings.     

Spontaneous and stimulated interleukin-6 and tumor necrosis factor-alpha production at delivery and three months after birth

OBJECTIVE: To study the production and interrelations of maternal and neonatal cytokines (IL-6 and TNF-alpha) during labor, after vaginal delivery and at three months after delivery. METHOD: The unstimulated concentrations of cytokines in the supernatants of whole-blood cultures and concentrations after PMA (phorbol 12-myristate 13-acetate) and concanavalin (conA) stimulation were determined by enzyme-linked immunosorbent assays (ELISAs). The blood samples were from the peripheral veins of 27 healthy women during term labor and immediately after delivery and three months after delivery. Neonatal samples were taken at birth (cord blood) and three months after delivery. RESULTS: IL-6 responses to stimulation were increased in the parturients and in umbilical cord blood at delivery compared with maternal and neonatal samples obtained 3 months postpartum. In contrast, the production of maternal TNF-alpha in peripheral blood was down-regulated at delivery compared with values 3 months postpartum. After an IL-6 and TNF-alpha burst in umbilical cord samples, neonatal cytokine production was at a low level three months after delivery. IL-6 production tended to be higher in both umbilical cord blood as well as in maternal samples after delivery in women who were younger. In addition, TNF-alpha production in umbilical cord blood was significantly higher in those women who were younger. CONCLUSIONS: The production of IL-6 was up-regulated in both the maternal and in umbilical cord blood at delivery. The production of TNF-alpha was up-regulated in umbilical cord blood compared with neonatal values 3 months after birth. Maternal age had effects on IL-6 and TNF-alpha production at delivery.     

Genotoxicity of gliotoxin,a secondary metabolite of Aspergillus fumigatus,in a battery of short-term test systems

The genotoxic effects of gliotoxin, a known fungal secondary metabolite, were studied. Gliotoxin was purified from cultivation medium of Aspergillus fumigatus isolated from the indoor air of a moisture problem house. The genotoxicity of gliotoxin was assessed both in bacterial test systems including bacterial repair assay, Ames Salmonella assay and SOS-chromotest, and in mammalian cells using single cell gel (SCG) electrophoresis assay and sister-chromatid exchange (SCE) test. Gliotoxin was found to be genotoxic in the bacterial repair assay but, not in the Salmonella test or SOS-chromotest. A dose-related increase in DNA damage was observed in mouse RAW264.7 macrophages exposed to gliotoxin for 2h in plain medium in the SCG assay. In contrast to the positive response in the SCG assay, gliotoxin did not induce any clear, dose-related increase in SCEs in Chinese hamster ovary (CHO) cells.     

Metabolite profiles of Stachybotrys isolates from water-damaged buildings and their induction of inflammatory mediators and cytotoxicity in macrophages

The metabolite profiles of 20 Stachybotrys spp.isolates from Finnish water-damaged buildings were compared with their biological activities. Effects of purified compounds on cytotoxicity and production of inflammatory mediators such as nitric oxide, IL-6 and TNFα in murine RAW264.7 macrophage cells were studied. The 11isolates belonging to the satratoxin-producing chemotype were highly cytotoxic to the macrophages. The isolates inducing inflammatory mediators all belonged to the atranone-producing chemotype, but pure atranones B, and D did not elicit a response in the bioassay. Altogether, cytotoxicity ofStachybotrys sp. isolates appear to be related to satratoxin production whereas the specific component inducing inflammatory responses in atranone-producing isolates remains obscure. This revised version was published online in June 2006 with corrections to the Cover Date.     

Time-course of malaoxon-induced alterations in brain regional inositol-1-phosphate levels in convulsing and nonconvulsing rats

The potential of a single dose of malaoxon (26.2 or 39.2 mg/kg i.p.) to produce convulsions and to increase cerebral levels of inositol-1-phosphate (Ins1P), an intermediate in phosphoinositide (PI) cycle, was followed for 1, 4, or 72 hr. The lower dose of malaoxon did not produce convulsions whereas the higher dose induced convulsions in 60% of the exposed rats. Malaoxon caused a dosedependent, at most 2-fold, increase in brain regional Ins1P levels in nonconvulsing rats as compared to controls. At the higher dose of malaoxon, in convulsing rats, the Ins1P-levels increased 4-fold above the control Ins1P-levels. In nonconvulsing rats, the Ins1P-levels reached their maximum 1–4 hr after the administration of malaoxon, whereas in convulsing rats the levels increased for 72 hr. The results suggest that PI-signalling is associated with convulsions produced by malaoxon.     

Genotoxicity of gliotoxin, a secondary metabolite of Aspergillus fumigatus, in a battery of short-term test systems

The genotoxic effects of gliotoxin, a known fungal secondary metabolite, were studied. Gliotoxin was purified from cultivation medium of Aspergillus fumigatus isolated from the indoor air of a moisture problem house. The genotoxicity of gliotoxin was assessed both in bacterial test systems including bacterial repair assay, Ames Salmonella assay and SOS-chromotest, and in mammalian cells using single cell gel (SCG) electrophoresis assay and sister-chromatid exchange (SCE) test. Gliotoxin was found to be genotoxic in the bacterial repair assay but, not in the Salmonella test or SOS-chromotest. A dose-related increase in DNA damage was observed in mouse RAW264.7 macrophages exposed to gliotoxin for 2 h in plain medium in the SCG assay. In contrast to the positive response in the SCG assay, gliotoxin did not induce any clear, dose-related increase in SCEs in Chinese hamster ovary (CHO) cells.     

Carbachol- and KCl-induced changes in phosphoinositide metabolism and free calcium in guinea pig cerebral cortex synaptosomes

Phosphoinositide (PI) and calcium metabolism were studied in guinea pig cerebral cortex synaptosomes. Mass amounts of inositol and inositol monophosphates, and the levels of free intrasynaptosomal calcium ([Ca²⁺]_i) were measured after KCl (60 mM), after a direct cholinergic agonist carbachol (CA, 1mM), and after their combination. Inositol, inositol-1-phosphate (Ins1P), inositol-4-phosphate (Ins4P) and [Ca²⁺]_i were measured with and without 10 mM LiCl in the incubation medium. CA-induced cholinergic stimulation elevated synaptosomal Ins4P levels by 40% but did not affect Ins1P or [Ca²⁺]_i. On the contrary, KCl elevated Ins1P by 50% and [Ca²⁺]_i by 40% above the resting level, and decreased inositol by 20%, whereas no alterations in Ins4P occurred. CA did not modify the response of KCl, but KCl abolished the elevation of Ins4P by CA. LiCl attenuated KCl-induced elevation of Ins1P but amplified the CA-induced elevation of Ins4P. The elevation of presynaptic [Ca²⁺]_i was accompanied by accumulation of Ins1P but not that of Ins4P. Hence, the present results suggest that presynaptic cholinergic stimulation and KCl-induced depolarization may activate different degradation pathways of inositolphosphate metabolism.     

Heparin modulates the growth and adherence and augments the growth-inhibitory action of TNF-alpha on cultured human keratinocytes

Previous works suggest the involvement of mast cells in the epithelialization of chronic wounds. Since heparin is a major mediator stored in the secretory granules of mast cells, the purpose of this work was to elucidate the function of heparin in epithelialization using in vitro culture models. For this, low- and high-calcium media in monolayer and epithelium cultures of keratinocytes were used. Also, an assay based on keratinocyte adherence onto plastic surface was used as well. Heparin (0.02-200 microg/ml) inhibited keratinocyte growth in a non-cytotoxic and dose-dependent manner in low- and high-calcium media, Keratinocyte-SFM and DMEM, in the absence of growth factors and serum. Also, heparin inhibited the growth of keratinocyte epithelium in the presence of 10% fetal calf serum and DMEM. Instead, in the presence of Keratinocyte-SFM and growth factors, heparin at 2 microg/ml inhibited the growth by 18% but at higher heparin concentrations the inhibition was reversed to baseline. TNF-alpha is another preformed mediator in mast cell granules and it inhibited keratinocyte growth in monolayer and epithelium cultures. Interestingly, heparin at 2-20 microg/ml augmented or even potentiated this growth-inhibitory effect of TNF-alpha. The association of TNF-alpha with heparin was shown by demonstrating that TNF-alpha bound tightly to heparin-Sepharose chromatographic material. However, heparin could not augment TNF-alpha-induced cell cycle arrest at G0/G1 phase or intercellular adhesion molecule-1 expression in keratinocytes. In the cell adherence assay, heparin at 2 microg/ml inhibited significantly by 12-13% or 33% the adherence of keratinocytes onto the plastic surface coated with fibronectin or collagen, respectively, but this inhibition was reversed back to baseline at 20 or 200 microg/ml heparin. Also, heparin affected the cell membrane rather than the protein coat on the plastic surface. In conclusion, heparin not only inhibits or modulates keratinocyte growth and adherence but it also binds and potentiates the growth-inhibitory function of TNF-alpha.     

A gas chromatographic method for the determination of inositol monophosphates in rat brain

Regional levels of cerebral inositol-1-phosphate (Ins1P), an intermediate in phosphoinositide (PI) cycle, were readily detected with a new gas chromatographic (GC) method. GC analysis of trimethylsilyated Ins1P and myo-inositol-2-phosphate with a fused silica capillary SE-30 column and flame ionization detection was linear at picomolar range (pmol/l) with a sensitivity to a level of 2 pmol. Also, inositol monophosphates and glucose-6-phosphate are separated in unstimulated brain tissue. The mean recovery of the method is 98±5.2%. Ins 1P levels were higher in frontal than in caudal regions in control brains. Lithium treatment increased the levels of Ins1P throughout the brain but mostly in frontal brain regions and in the hippocampus. The present GC assay to measure the accumulation of Ins1P, an index for the activity of PI signalling, may be suitable for exploring regional differences in cerebral receptor-coupled PI signalling in vivo.     

Effect of plasterboard composition on Stachybotrys chartarum growth and biological activity of spores

The effects of plasterboard composition on the growth and sporulation of Stachybotrys chartarum as well as on the inflammatory potential of the spores were studied. S. chartarum was grown on 13 modified plasterboards under saturated humidity conditions. The biomass was estimated by measuring the ergosterol content of the S. chartarum culture while the spore-induced cytotoxicity and production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin-6 in mouse macrophages was used to illustrate the bioactivity of spores. The ergosterol content of S. chartarum correlated with the number of spores collected from plasterboards. The growth and sporulation decreased compared to that of the reference board in those cases where (i) the liner was treated with biocide, (ii) starch was removed from the plasterboard, or (iii) desulfurization gypsum was used in the core. Spores collected from all the plasterboards were toxic to the macrophages. The biocide added to the core did not reduce the growth; in fact, the spores collected from that board evoked the highest cytotoxicity. The conventional additives used in the core had inhibitory effects on growth. Recycled plasterboards used in the core and the board lacking the starch triggered spore-induced TNF-alpha production in macrophages. In summary, this study shows that the growth of a strain of S. chartarum on plasterboard and the subsequent bioactivity of spores were affected by minor changes to the composition of the core or liners, but it could not be totally prevented without resorting to the use of biocides. However, incomplete prevention of microbial growth by biocides even increased the cytotoxic potential of the spores.