Altered learning by recipients of brain extracts from trained and retrained donors

Male C57B1/6J mice were trained to make either left or right turns in a Y maze to receive a food reward. One group was trained to criterion in one day; another group was similarly trained and maintained at that level of training for four additional days. The water-soluble fraction of the donor brains was transferred by subdural injection to recipient animals of the same strain. Recipients trained to the same side as their donors required fewer trials to reach criterion than did recipients trained to the opposite side. There was no effect due to maintenance of donor training. In addition, donor and recipient performance was negatively correlated.     

Respiratory effects of a synthetic metalworking fluid and its components

 A synthetic metalworking fluid, MWF “A”, and its major components were evaluated using a previously developed mouse bioassay. This fluid and its components evoked sensory (S) and pulmonary (P) irritation in mice. For MWF “A” and each of its components, a concentration-response relationship was developed on the basis of respiratory frequency (f_R) responses. From such relationships, the concentration capable of evoking a 50% decrease in mean f_R was determined for MWF “A” and each component (RD₅₀). RD₅₀S or RD₅₀P was used to distinguish decreases in f_R that were due to sensory irritation (S) from those due to pulmonary irritation (P). From RD₅₀P values, it was concluded that the fatty acid alkanolamide condensates, tolutriazole, and triazine-type biocide components were similar in potency to one another and similar in potency to MWF “A”. By examining potency and fractional composition, it was concluded that the fatty acid alkanolamide condensates and the triazine-type biocide largely contributed to the irritancy of MWF “A”. From RD₅₀P values, occupational exposure limits were proposed for MWF “A” and each of its components. The current Threshold Limit Value of 10 mg/m³ established by the American Conference of Governmental Industrial Hygienists for “particulates not otherwise classified” (PNOC) would be inadequate to protect workers from the irritating properties of MWF “A” and most of its components. Received: 16 March 1995 / Accepted: 21 August 1995     

The use of human lymphoid cell line lymphokine preparations (LCL-LK) as working standards in the bioassay of human leucocyte migration inhibition factor (LIF)

The leucocyte migration inhibition test in agarose as described by Clausen (1971) was modified into a statistically designed assay of LIF activity using human polymorphonuclear leucocytes from single blood donors. Individual assays included a laboratory standard of lymphokine with LIF activity prepared from the culture supernatants of the RPMI 1788 human lymphoblastoid cell line (LCL-LK). Analysis of 157 LIF assays revealed simple criteria by which the acceptability of an individual assay could be judged before subjecting it to statistical analysis. The failure of LIF assays to meet these criteria of acceptability was particularly associated with low areas of control polymorph migration in the absence of lymphokine (‘spontaneous migration’).We demonstrate that the statistically designed assay permits the measurement, with precision, of LIF activity in units/ml by reference to a working standard of LCL-LK. We illustrate the use of this assay in the measurement of LIF activity generated by tuberculin-stimulated human peripheral blood lymphocytes.     

Mutagenicity and chemical analysis of airborne particulates from a rural area in italy

Mutagenic activities of a sample of characterized airborne particulates collected in a rural location near Ispra (Italy) during the summer of 1980 were detected by the Ames test using TA 1537, TA 1538, TA 98, and TA 100 Salmonella strains. Eight chemical classes fractionated from the CH₂Cl₂ extract of the particulates were bioassayed, and their mutagenicities (TA 98 plus S9) were as follows: organic bases I > polar neutrals > insolubles in cyclohexane > organic acid II > aerosol “in toto” > intermediate neutrals > polycyclic aromatic hydrocarbons > organic acids I > nonpolar neutrals. Periodical samples were taken in the same location from March to December 1981, extracted in dimethyl sulfoxide (DMSO), and directly tested with TA 1537, TA 98, and TA 100 Salmonella strains. For all the strains the mutagenicity varied markedly according to the season, the cold-month samples being much more mutagenic than the summer-month samples. The additional of S9 increased the mutagenicity (twofold) of the cold-month samples. The higher mutagenicity of the samples collected during the cold months could be due to greater amounts of mutagens produced by the combustion processes of domestic heating.     

Secondary metabolites from Chamaedora tepejilote (Palmae) are active against Mycobacterium tuberculosis

Due to the emergence of multi-drug resistant Mycobacterium tuberculosis strains, there is an urgent need to search for new antimycobacterial drugs. The present work describes the bioactivity-guided fractionation of Chamaedora tepejilote hexane extract which led to the isolation and the characterization of squalene, farnesol, methylic ester of hexadecanoic acid, beta-sitosterol and ursolic acid. Activity against Mycobacterium tuberculosis H37Rv, determined by radiorespirometric Bactec assay, showed ursolic acid, squalene and farnesol to produce a M. tuberculosis growth inhibition of 99% at a concentration of 100 microg/mL.     

Enhancement of domoic acid neurotoxicity on Diptera larvae bioassay by marine fungal metabolites

Peptaibols are small linear fungal peptides which are produced in the marine environment. They exhibit neurotoxicity by forming pores in neuronal membranes. This work describes their combine effect with domoic acid, a neurotoxic phycotoxin, on Diptera larvae. The Acute toxicity bioassay on this biological model was tested with a panel of different toxins (microbial, algal or fungal). It allowed the discrimination of neurotoxins and non-neurotoxic toxins, and an evaluation of the toxicity level (MED and ED₅₀) which were correlated with published LD₅₀ in mice for neurotoxins tested. The highest activities on this test were found for Na⁺ channel blockers tetrodotoxin (ED₅₀ = 0.026 mg/kg) and saxitoxin (ED₅₀ = 0.18 mg/kg). Domoic acid was less active with an ED₅₀ = 7.6 mg/kg. For synergism study, longibrachin-A-I, a 20-mer peptaibol isolated from cultures of a marine-derived strain of Trichoderma longibrachiatum Rifai was chosen. Bioassay results confirmed its neuroactivity. Its level of toxicity (ED₅₀ = 270 mg/kg) was lower than those of phycotoxins tested but higher than mycotoxin ones. Injected together, longibrachin-A-I and domoic acid exhibited an increase of their activities. With doses of longibrachin-A-I below its Minimal Effective Dose (MED), the synergism factor which expresses the enhancement of domoic acid toxicity could reach 34.5. Both domoic acid and longibrachin-A-I are acting on ion channels and pores in neuronal membranes which contribute to the intake of Ca²⁺ into cells.     

Antimycotic Activity of 20 Plants from Colombian Flora

Abstract

The antifungal activities of 65 extracts were evaluated through the agar well diffusion method in 22 plant samples from the Ucumari Natural Regional Park (UNRP). These samples belong to 20 plant species related to the following botanic families: Asteraceae, Euphorbiaceae, Melastomataceae, Podocarpaceae, Rubiaceae and Solanaceae. The plant extracts were obtained in hexanes, dichloromethane and methanol. The 65 extract samples were tested against pathogenic fungi Aspergillus fumigatus (ATCC 1022), Candida albicans (ATCC 18804) and Fusarium solani (ATCC 11712). Ketoconazole was used as positive control. The methanol extracts from Solanum spp. (FJR 3155) and Tibouchina grossa exhibited the greatest inhibitory activity against the three fungi tested, while the methanol extracts from Hyeronima macrocarpa, Miconia lehmannii, and Sapium stylare inhibited two of the fungi assayed. The dichloromethane extracts from Miconia lehmannii Cong, Lycinathes acutifolia and Solanum spp. (FJR 3155) inhibited two of the three fungi tested, while the dichloromethane extracts from Cinchona pubescens Vahl and Palicourea spp. (FJR 3182) inhibited one of the three microorganism tested. Only one of the hexane extracts produced activity against the three fungi tested.     

Quality Control Approaches for Chinese Herbal Medicines

The current official quality control approaches meet the challenges from the complexity of herbal medicines. In fact, any herbal medicines containing numerous unknown components, its curative effect usually depends on the whole of herbal medicines, so it is impossible and unnecessary to qualitatively and quantitatively study every component. By investigating the limitations of current quality control approaches for herbal medicines and the difference and similarity in the chemical substantial style as well as quality control pattern of herbal medicines, a new quality control approach for Chinese herbal medicines should be explored and designed. The combination approach of chemical analysis with bioassay is promising to be developed and employed in order to ensure the safety and efficacy of Chinese herbal medicines.     

Assessing the estrogenic activity of chemicals present in resin based dental composites and in leachates of commercially available composites using the ERα-CALUX bioassay

ObjectiveThe biocompatibility of resin based dental composites has not yet been fully characterized even though certain monomers used in these composites are synthesized from Bisphenol A (BPA), a well-known estrogenic endocrine disruptor. As a result, they show structural relationship to BPA and can contain it as an impurity. Therefore, the estrogenic activity of 9 monomers, 2 photoinitiators, one photostabilizer and leachates of 4 commercially available composites was determined.MethodsThe ERα-CALUX bioassay was used to determine both agonistic and antagonistic estrogenic activities of the pure compounds (BPA, BisDMA, BisGMA, BisEMA(3), BisEMA(6), BisEMA(10), TEGDMA, TCD-DI-HEA, BADGE, UDMA, HMBP, DMPA, CQ) and the leachates of cured composite disks. The leachates of 4 commercially available composites (Solitaire 2, Ceram.x Spectra ST, G-ænial Posterior and Filtek Supreme XTE) in water and 0.1 M NaOH (pH = 13, ‘worst-case scenario’) were tested for estrogenic activity (pooled leachates from 10 cured composite disks).ResultsAgonistic estrogenic activity was found for the monomer BisDMA, the photostabilizer HMBP and photoinitiator DMPA. All leachates from the 4 tested composites showed significant agonistic estrogenic activity higher than the DMSO control, and the highest activity (potency and efficacy) was found for Solitaire 2, followed by Ceram.x Spectra ST. Furthermore, antagonistic estrogenic activity was found in the leachates from G-ænial Posterior.SignificanceThese results show that significant estrogenic activity was found in all leachates of the cured composite disks, and that this estrogenicity is most likely due to a mixture effect of multiple estrogenic compounds (including BPA, HMBP and DMPA). This indicates that further research into the endocrine activity of all the compounds that are present in these composites (even at low quantities) and their possible mixture effect is warranted to guarantee their safe use.