This article is available online at http://www.jlr.org uct, formed during storage of cholesterol or artifactually produced during work-up of tissue samples ( 1, 2 ). Enzymatic formation of 25-hydroxycholesterol by rat liver mitochondria was described in 1974 ( 3 ), and it was later shown that 25-hydroxycholesterol is formed as a by-product during cholesterol oxidation by the mitochondrial enzyme sterol 27-hydroxylase in liver in pig ( 4 ) and mouse ( 5 ). In addition to the formation of 25-hydroxycholesterol by sterol 27-hydroxylase (CYP27A1), a specifi c human microsomal cholesterol 25-hydroxylase has been cloned and characterized ( 6 ). This enzyme does not belong to the cytochrome P450 family but is related to the eukaryotic stearoyl-CoA desaturases ( 6 ). Low levels (3-5 ng/ml) of 25-hydroxycholesterol are present in human plasma ( 7 ), but the relative contribution of CYP27A1 and cholesterol 25-hydroxylase to its formation is not known.25-Hydroxycholesterol is a potent regulatory oxysterol and may participate in several aspects of lipid metabolism ( 8 ). A family of oxysterol binding proteins with high affi nity for 25-hydroxycholesterol has been identifi ed ( 9 ). Overexpression of oxysterol binding proteins in Chinese hamster ovary cells resulted in signifi cant changes in genes involved in lipid metabolism ( 10 ). Side chain oxidized oxysterols, such as 25-hydroxycholesterol, have been implicated in the regulation of cholesterol homeostasis for a long time but only recently was the mechanism clarifi ed. These oxysterols bind to proteins called Insigs, thereby blocking the sterol regulatory element binding protein signaling that regulates cholesterol biosynthesis ( 11 ). Furthermore, 25-hydroxycholesterol has been shown to activate the nuclear receptor

High-resolution photoemission (⌬Eϭ5 meV) at a low photon energy ͑3.82 eV͒ is used to probe discrete quantum-well-type subband states near, below, and above E F for Cu͑111͒ covered with 2 ML or less of Na. A subband characteristic of the monolayer range shifts gradually to lower energy as the coverage is increased, extending below the Fermi level for coverages above 0.85 ML. Combined with previous observations of shifts for filled and empty states the present results show that the Na monolayer has continuously tunable quantumwell state energies. Beyond the monolayer range quantum-well states characteristic of both one and two atomic layers are observed, indicating growth of the second layer via monolayer high islands. A small downshift, by 25 meV, with increasing coverage in the second layer is ascribed to an increase of the island size. Lorentzian photoemission line shapes are observed for well-ordered samples. The linewidth varies linearly with temperature in the probed range ͑130-295 K͒ and this is ascribed to the phonon contribution to the width. Structural disorder leads to an asymmetric line, which is Lorentzian on the steeper, low-kinetic-energy side.

Online biomonitors register biological effects of toxic discharges on selected indicator species and allow for fast, continuous, and ecological relevant water quality control. This paper presents a new online biomonitor based on a quadropole impedance conversion technique that records simultaneously several behavioral parameters of Gammarus pulex, a new biomonitoring test species. The behavior of two different populations of G. pulex was compared; one population originated from an anthropogenically unpolluted stream, and the other population lived at the copper-polluted study site, where the biomonitor was placed. Responses to simulated copper pollution peaks of 70 μg of Cu2+/L were registered in the biomonitor and compared to the natural drift. G. pulex was the most abundant species in the natural drift. A nocturnal drift maximum was found in the natural drift and for both popula tions in the biomonitor. Mortality was high in the biomonitor; the local population survived slightly better than the reference population. The reference population showed significantly less activity than the local population measured as number of active organisms per day and time spent on locomotion and ventilation. Copper pollution pulses provoked increases in number of active organisms and time spent on locomotion in the biomonitor; however, no significant changes in the natural drift were registered.

Oxelius V-A, Aurivillius M, Carlsson A-M, Musil K. Serun Gm Allotype Development During Childhood. Scand J Immunol 1999;50:440±446 Gm allotypes are genetic variants of the immunoglobulin heavy G chains (IGHG) of IgG molecules, coded from chromosome 14q32, characterized by differences in amino acid epitopes of the constant heavy G chains and inherited in the Mendelian manner. Gm allotypes have in¯uence on IgG subclass levels, and serum Gm allotype levels have been given for different Gm genotypes in adults. Four hundred and thirty healthy children, aged 1±15 years, were examined for serum Gm allotypes and IgG subclasses from the six most common Gm genotypes and different age groups were measured using competitive enzyme-linked immunosorbant assay and radial immunodiffusion methods. Quantities (in g/l) of G1m(a) and G1m(f) of IgG1, G2m(n) and G2m(± n) of IgG2 and G3m(g), and G3m(b) of IgG3 are given. Different maturation rates of the alternative Gm allotypes within IgG1, IgG2 and IgG3 were shown. G2m(n) development was strikingly retarded compared with G2m(±n) from the g2 locus. This was found comparing IgG2 levels from homozygous G2m(±n±n) and G2m(nn) individuals, but was also seen in heterozygous G2m(n±n) genotypes. From the g1 locus G1m(f) levels dominated signi®cantly, but inconstantly, over G1m(a) levels in heterozygous G1m(af) individuals. In homozygous G1m genotypes, G1m(aa) compared with G1m(ff) of the same age, one or the other dominated, sometimes signi®cantly. Serum levels of G3m(b) from the g3 locus of homozygous G3m(bb) individuals were increased signi®cantly compared with G3m(g) levels of homozygous G3m(gg) individuals, in ages over 3 years. However, in heterozygous G3m(gb) individuals G3m(b) dominance was not evident. There is a relatively rapid development of G1m(f) molecules and a retarded development of G2m(n) in the Gm(f;n;b) haplotype. In comparison, G1m(a) is retarded and G2m(±n) is enhanced in the Gm(a;±n;g) haplotype. The retarded serum G2m(n) development is comparable with serum IgA development during childhood. Different maturation rates of Gm allotypes within the same IgG subclass provide further explanation for the variation of the antibody response during childhood. Quantitative Gm allotype determinations give information of the activity from IGHG genes. The genetic variation constitutes an additional basis for evaluation of IgG antibodies in different diseases in childhood.

Our data demonstrate the importance of developing a programme for the prevention of paediatric scalds with education of family members to be aware of the danger. With present study the knowledge about the occurrence of injuries in scald accidents in children has become deeper. This knowledge may contribute to more individual adept child accident prevention programme, to use in the child health care.

A method for quantitation of Gm allotypes is described. Alternative Gm allotypes of the three IgG subclasses, IgG1, IgG2 and IgG3, were investigated for the six most common Caucasian Gm phenotypes. Quantitation of G1m(a), G1m(f) of IgG1, G2m(n) of IgG2 and G3m(b) of IgG3 was performed with specific monoclonal antisera and purified myeloma proteins of different Gm allotypes. Mean +/- SD are given as percentage of a normal serum pool and in g/l for the Gm allotypes G1m(a), G1m(f), G2m(n) and G3m(b). For homozygous individuals the G2m(",") values are equal to the IgG2 levels and the G3m(g,g) values equal to the IgG3 levels. For heterozygous individuals the value for G2m(") is calculated as IgG2 minus G2m(n) and for G3m(g) as IgG3 minus G3m(b). Homozygous individuals have about double the amounts of the Gm allotype compared with heterozygous individuals. The gene activity of heterozygous individuals is given by quotients, mean +/- SD for G1m(a)/G1m(f) of IgG1, G2m(n)/G2m(") of IgG2 and G3m(b)/G3m(g) of IgG3 in different Gm phenotypes. Heterozygous individuals on all three IgG subclass loci have at least six different qualities of IgG molecules compared with three for homozygous individuals.

The EvaRID dummy model demonstrated the potential of becoming a valuable tool when evaluating and developing seats and whiplash protection systems. However, updates of the joint stiffness will be required to provide better correlation at lower load levels. Moreover, the seated posture, curvature of the spine, and head position of 50th percentile female occupants needs to be established and implemented in future models.

The overall result indicated differences in the dynamic response for the female and male volunteers. The results could be used in developing and evaluating a mechanical and/or mathematical average-sized female dummy model for rear impact safety assessment. These models can be used as a tool in the design of protective systems and for further development and evaluation of injury criteria.