The effects of ventilation and the dilution of smoke upon the clastogenic and aneugenic activity of tobacco particulate matter in cultured mammalian cells.

We demonstrate here that tobacco particulate matter (TPM) produced from both non-ventilated and ventilated cigarettes of varying tar contents induced structural and numerical aberrations in cultured Chinese hamster cells. Our data indicate that TPM from ventilated cigarettes is of lower potency in inducing both clastogenic and aneugenic effects compared with TPM from non-ventilated cigarettes. These observations provide support for the concept that the genotoxic activity (to cultured Chinese hamster cells) of cigarette smoke is reduced by increased ventilation to a greater extent than a 1:1 ratio between yield reduction and smoke dilution.

Sex determination in the genus Oreochromis : 2. Sex reversal, hybridisation, gynogenesis and triploidy in O. aureus Steindachner.

Sex ratios from 62 single-pair matings of normal broodstock O. aureus were highly heterogeneous with an overall deficit of males (41.4%).

Sex determination in the genus Oreochromis : 1. Sex reversal, gynogenesis and triploidy in O. niloticus (L.).

Established techniques of genetic manipulation were used to elucidate sex-determining mechanisms in the commercially important tilapia, Oreochromis niloticus. Analysis of sex ratios from single-pair matings of normal broodstock showed these to be heterogeneous, with an asymmetrical frequency distribution. Data were homogeneous, with the exclusion of a number of broods with sex ratios not significantly different from 3∶1 (male: female), and further progeny testing revealed atypical female heterogamety in the parents of these broods.

32P-postlabelling analysis and micronuclei induction in primary Chinese hamster lung cells exposed to tobacco particulate matter.

The genotoxicity of tobacco particulate matter (TPM) derived from a low-tar, low-nicotine cigarette has been examined by measuring micronucleus induction in a primary pulmonary cell line, both in the absence and presence of an exogenous source of metabolic activation. In an attempt to correlate the cytogenetic damage observed with DNA adduct formation, DNA extracted from TPM-treated cells has been analysed with two different modifications of the 32P-postlabelling assay. The results from the 32P-postlabelling analysis taken together with the pattern of micronucleus induction provide strong evidence that bioreactivated aromatic carcinogens, such as benzo[a]pyrene, are unlikely to be responsible for the TPM-induced cytogenetic damage observed in cultured mammalian cells.

Lipoxin formation in fish leucocytes.

Adherent leucocytes, consisting of mainly macrophages, isolated from the haemopoietic head kidney of five species of fish were challenged with calcium ionophore and the resulting lipoxygenase products were separated and identified by reverse-phase high performance liquid chromatography. Of the fish examined, only adherent leucocytes from the Atlantic salmon and mirror carp generated lipoxins. Atlantic salmon leucocytes synthesized mainly lipoxin (LX) A4/LXA5 and 11-trans-LXA4/11-trans-LXA5, while mirror carp produced both LXA4 and LXB4 and their isomers but no 5-series lipoxins.

Synthesis of lipoxins and other lipoxygenase products by macrophages from the rainbow trout, Oncorhynchus mykiss.

Rainbow trout macrophages maintained in short term culture when incubated with either calcium ionophore, A23187, or opsonized zymosan synthesize a range of lipoxygenase products including lipoxins and leukotrienes. These cells are unusual in that they generate more lipoxin than leukotriene following such challenge. The main lipoxin synthesized was lipoxin (LX) A4.

The psychological benefit of orthodontic treatment. Its relevance to dental health education.

In March 1989 the third stage of a major longitudinal survey examining the psychological, social and dental effects of malocclusion and the effectiveness of orthodontic treatment was undertaken. The aim of the research was to assess the benefit of receiving dental treatment with a particular interest in orthodontic treatment. The benefits investigated were dental, psychological and social.

Children's early understanding of false belief.

We investigated 3-year-olds' understanding of the representational capability of the mind by examining whether they would acknowledge that they had entertained a wrong belief. As in previous studies, children very often judged that they had believed a Smarties tube contained pencils when these were revealed as the true content, even though they had stated "Smarties" before the tube had been opened. Under another condition, when the tube was first presented, children mailed a picture into a postbox of what they thought was inside (Smarties).

Double-ionization energies to ground and excited states of the tungsten hexacarbonyl dication.

Tungsten hexacarbonyl was investigated by double-charge-transfer (DCT) spectroscoPy, and the double-ionization energies to ground and electronically excited states of W(CO) 6 (2+) determined. The double-ionization energies corresponding to the first two distinct peaks in the spectra are 22.8 ± 0.

Analysis of sulphonamides using supercritical fluid chromatography and supercritical fluid chromatography-mass spectrometry.

Packed-column supercritical fluid chromatography has been used for the separation of mixtures of sulphonamides on silica and amino-bonded stationary phases utilizing carbon dioxide with methanol modifier as the mobile phase. The effect of modifier concentration, column pressure and modifier identity on retention was also studied. Packed-column supercritical fluid chromatography-mass spectrometry (SFC-MS) of these mixtures utilizing both moving-belt and modified thermospray interfaces was also studied.

Trace element analysis in body fluids by glow discharge mass spectrometry: a study of lead mobilization by the drug cis-platin.

A method is described, using glow discharge mass spectrometry, to measure lead and platinum levels at the p.p.b.

Effects of prenatal exposure to benzodiazepine-related drugs on early development and adult social behaviour in Swiss mice--II. Antagonists.

1. The present experiment examined, using a battery of tests, the effects of in utero exposure of Swiss mice to the benzodiazepine antagonists Ro 15-1788 and CGS 8216 upon early development and adult behaviour. 2.

Activation of the prophenoloxidase cascade and initiation of nodule formation in locusts by bacterial lipopolysaccharides.

The activation of the prophenoloxidase (proPO) system of the locusts, Schistocerca gregaria and Locusta migratoria, by several bacterial lipopolysaccharides (LPS) is described. Activation of proPO by LPS occurred only in the presence of whole blood homogenates and not with hemocyte lysate preparations alone. Levels of phenoloxidase generated by the different LPSs in vitro were also correlated with numbers of nodules formed in vivo by injection of these LPSs.

Ethopharmacological studies on the effects of antihormones on rodent agonistic behavior with especial emphasis on progesterone.

The effects of a range of antiandrogens and antiestrogens on conflict behaviors in laboratory rats and mice are reassessed in the light of recent studies applying ethophamacological analyses (recording the full spectrum of behaviors) to such investigations. It is argued that any antihostility properties of the antiandrogen cyproterone acetate are largely a consequence of indirect actions on odor communication, whereas antiestrogens (e.g.

Fatty acid composition and lipoxygenase metabolism in blood cells of the lesser spotted dogfish, Scyliorhinus canicula.

1. The fatty acid composition of erythrocytes and leucocytes of the elasmobranch, Scyliorhinus canicula, was determined so as to indicate substrate availability for eicosanoid formation. 2.

Effects of prenatal exposure to benzodiazepine-related drugs on early development and adult social behaviour in Swiss mice--III. Inverse agonists.

1. The present experiment examined, using a battery of tests, the effects of in utero exposure to the benzodiazepine inverse agonists DMCM and FG 7142 upon the early development and adult behaviour of Swiss Mice. 2.

Effects of prenatal exposure to benzodiazepine-related drugs on early development and adult social behaviour in Swiss mice--I. Agonists.

1. The present experiment examined, using a battery of tests, the effects of in utero exposure to the benzodiazepine agonists chlordiazepoxide and midazolam upon the early development and adult behaviour of offspring of Swiss mice. 2.

Exploring the relationship between reflectance red edge and chlorophyll content in slash pine.

Chlorophyll is a key indicator of the physiological status of a forest canopy. However, its distribution may vary greatly in time and space, so that the estimation of chlorophyll content of canopies or branches by extrapolation from leaf values obtained by destructive sampling is labor intensive and potentially inaccurate. Chlorophyll content is related positively to the point of maximum slope in vegetation reflectance spectra which occurs at wavelengths between 690-740 nm and is known as the "red edge.