Exposure of rats to a high but not low dose of ethanol during early postnatal life increases the rate of loss of optic nerve axons and decreases the rate of myelination

Visual system abnormalities are commonly encountered in the fetal alcohol syndrome although the level of exposure at which they become manifest is uncertain. In this study we have examined the effects of either low (ETLD) or high dose (ETHD) ethanol, given between postnatal days 4-9, on the axons of the rat optic nerve. Rats were exposed to ethanol vapour in a special chamber for a period of 3 h per day during the treatment period. The blood alcohol concentration in the ETLD animals averaged similar to 171 mg/dl and in the ETHD animals similar to 430 mg/dl at the end of the treatment on any given day. Groups of 10 and 30-d-old mother-reared control (MRC), separation control (SC), ETLD and ETHD rats were anaesthetised with an intraperitoneal injection or ketamine and xylazine, and killed by intracardiac perfusion with phosphate-buffered glutaraldehyde. In the 10-d-old rat optic nerves there was a total of similar to 145000-165000 axons in MRC, SC and ETLD animals. About 4 % of these fibres were myelinated. The differences between these groups were not statistically significant. However, the 10-d-old ETHD animals had only about 75000 optic nerve axone (P < 0.05) of which about 2.8 % were myelinated. By 30 d of age there was a total of between 75000 90000 optic nerve axons, irrespective of the group examined. The proportion of axons which were myelinated at this age was still significantly lower (P < 0.001) in the ETHD animals (similar to 77 %) than in the other groups (about 98 %). It is concluded that the normal stages of development and maturation of the rat optic nerve axons, as assessed in this study, can be severely compromised by exposure to a relatively high (but not low) dose of ethanol between postnatal d 4 and 9.

Case-only study of interactions between genetic polymorphisms of GSTM1, P1, T1 and Z1 and smoking in Parkinson's disease

Current opinion contends that complex interactions between genetic and environmental factors play a role in the etiology of Parkinson's disease (PD). Cigarette smoking is thought to reduce risk of PD, and emerging evidence suggests that genetic factors may modulate smoking's effect. We used a case-only design, an approach not previously used to study gene-environment interactions in PD, specifically to study interactions between glutathione-S-transferase (GST) gene polymorphisms and smoking in relation to PD. Four-hundred PD cases (age at onset: 60.0 +/- 10.7 years) were genotyped for common polymorphisms in GSTM1, PI, T1 and Z1 using well-established methods. Smoking exposure data were collected in face-to-face interviews. The independence of the studied GST genotypes and smoking exposure was confirmed by studying 402 healthy, aged individuals. No differences were observed in the distributions of GSTM1, T1 or Z1 polymorphisms between ever-smoked and never-smoked PD cases using logistic regression (all P > 0.43). However, GSTP1 *C haplotypes were over-represented among PD cases who ever smoked (odds ratio for interaction (ORi) = 2.00 (95% Cl: 1.11-3.60, P = 0.03)). Analysis revealed that ORi between smoking and the GSTP1-114Val carrier status increased with increasing smoking dose (P = 0.02 for trend). These data suggest that one or more GSTP1 polymorphisms may interact with cigarette smoking to influence the risk for PD. (C) 2004 Elsevier Ireland Ltd. All rights reserved.

Evolution of a mate recognition system after hybridization between two Drosophila species

I investigated the genetic relationship between male and female components of the mate recognition system and how this relationship influenced the subsequent evolution of the two traits, in a series of replicate populations of interspecific hybrids. Thirty populations of hybrids between Drosophila serrata and Drosophila birchii were established and maintained for 24 generations. At the fifth generation after hybridization, the mating success of hybrid individuals with the D. serrata parent was determined. The genetic correlation between male and female components of the male recognition system, as a consequence of pleiotropy or tight physical linkage, was found to be significant but low (r = 0.388). This result suggested that pleiotropy may play only a minor role in the evolution of mate recognition in this system. At the twenty-fourth generation after hybridization, the mating success of the hybrids was again determined. The evolution of male and female components was investigated by analyzing the direction of evolution of each hybrid line with respect to its initial position in relation to the genetic regression. Male and female components appeared to converge on a single equilibrium point, rather than evolving along trajectories with slope equal to the genetic regression, toward a line of equilibria.

Flush air data system calibration using numerical simulation

The use of computational fluid dynamics simulations for calibrating a flush air data system is described, In particular, the flush air data system of the HYFLEX hypersonic vehicle is used as a case study. The HYFLEX air data system consists of nine pressure ports located flush with the vehicle nose surface, connected to onboard pressure transducers, After appropriate processing, surface pressure measurements can he converted into useful air data parameters. The processing algorithm requires an accurate pressure model, which relates air data parameters to the measured pressures. In the past, such pressure models have been calibrated using combinations of flight data, ground-based experimental results, and numerical simulation. We perform a calibration of the HYFLEX flush air data system using computational fluid dynamics simulations exclusively, The simulations are used to build an empirical pressure model that accurately describes the HYFLEX nose pressure distribution ol cr a range of flight conditions. We believe that computational fluid dynamics provides a quick and inexpensive way to calibrate the air data system and is applicable to a broad range of flight conditions, When tested with HYFLEX flight data, the calibrated system is found to work well. It predicts vehicle angle of attack and angle of sideslip to accuracy levels that generally satisfy flight control requirements. Dynamic pressure is predicted to within the resolution of the onboard inertial measurement unit. We find that wind-tunnel experiments and flight data are not necessary to accurately calibrate the HYFLEX flush air data system for hypersonic flight.

Effects of beta-escin and saponin on the transverse-tubular system and sarcoplasmic reticulum membranes of rat and toad skeletal muscle

Mechanically skinned skeletal muscle fibres from rat and toad were exposed to the permeabilizing agents beta-escin and saponin. The effects of these agents on the sealed transverse tubular system (t-system) and sarcoplasmic reticulum (SR) were examined by looking at changes in the magnitude of the force responses to t-system depolarization, the time course of the fluorescence of fura-2 trapped in the sealed t-system, and changes in the magnitude of caffeine-induced contractures following SR loading with Ca2+ under defined conditions. In the presence of 2 mu g ml(-1) beta-escin and saponin, the response to t-system depolarization was not completely abolished, decreasing to a plateau, and a large proportion of fura-2 remained in the sealed t-system. At 10 mu g ml(-1), both agents abolished the ability of both rat and toad preparations to respond to t-system depolarization after 3 min of exposure, but a significant amount of fura-2 remained in sealed t-tubules even after exposure to 100 mu g ml(-1) beta-escin and saponin for 10 min. beta-Escin took longer than saponin to reduce the t-system depolarizations and fura-2 content of the sealed t-system to a similar level. The ability of the SR to load Ca2+ was reduced to a lower level after treatment with beta-escin than saponin. This direct effect on the SR occurred at much lower concentrations for rat (2 mu g ml(-1) beta-escin and 10 mu g ml(-1) saponin) than toad (10 mu g ml(-1) beta-escin and 150 mu g ml(-1) saponin). The reverse order in sensitivities to beta-escin and saponin of t-system and SR membranes indicates that the mechanisms of action of beta-escin and saponin are different in the two types of membrane. In conclusion, this study shows that: (1) beta-escin has a milder action on the surface membrane than saponin; (2) beta-escin is a more potent modifier of SR function; (3) simple permeabilization of membranes is not sufficient to explain the effects of beta-escin and saponin on muscle membranes; and (4) the t-system network within muscle fibres is not a homogeneous compartment.

Differentiation of the mononuclear phagocyte system during mouse embryogenesis: The role of transcription factor PU.1

During mouse embryogenesis, macrophage-like cells arise first in the yolk sac and are produced subsequently in the liver. The onset of liver hematopoiesis is associated with the transition from primitive to definitive erythrocyte production. This report addresses the hypothesis that a similar transition in phenotype occurs in myelopoiesis. We have used whole mount in situ hybridization to detect macrophage-specific genes expressed during mouse development. The mouse c-fms mRNA, encoding the receptor for macrophage colony-stimulating factor (CSF-1), was expressed on phagocytic cells in the yolk sac and throughout the embryo before the onset of liver hematopoiesis, Similar cells were detected using the mannose receptor, the complement receptor (CR3), or the Microphthalmia transcription factor (MITF) as mRNA markers. By contrast, other markers including the F4/80 antigen, the macrophage scavenger receptor, the S-100 proteins, S100A8 and S100A9, and the secretory product lysozyme appeared later in development and appeared restricted to only a subset of c-fms-positive cells. Two-color immunolabeling on disaggregated cells confirmed that CR3 and c-fms proteins are expressed on the same cells. Among the genes appearing later in development was the macrophage-restricted transcription factor, PU.1, which has been shown to be required for normal adult myelopoiesis. Mice with null mutations in PU.1 had normal numbers of c-fms-positive phagocytes at 11.5dpc. PU.1(-/-) embryonic stem cells were able to give rise to macrophagelike cells after cultivation in vitro. The results support previous evidence that yolk sac-derived fetal phagocytes are functionally distinct from those arising in the liver and develop via a different pathway. (C) 1999 by The American Society of Hematology.

Implications of specimen preparation and of surface contamination for the measurement of the grain boundary carbon concentration of steels using x-ray microanalysis in an UHVFESTEM

The purpose of the present investigation was to gain an understanding of the nature of the carbon contamination on the surface of standard steel transmission electron spectroscopy (TEM) specimens, the effect of exposure of a clean specimen to normal laboratory air, and the efficacy of plasma-cleaning treatments. This knowledge is a necessary prerequisite to the development of appropriate specimen preparation and/or specimen cleaning methods. X-ray photoelectron spectroscopy in combination with argon ion beam profiling was used to characterize the specimen surfaces of X65 steel and 316 stainless steel. The only clean carbon-free surface obtained was that during argon etching of the sample in the surface analysis chamber. Any exposure of a previously cleaned sample to laboratory air resulted in a rapid carbon (hydrocarbon) contamination of the sample surface and the development of surface oxidation, Plasma cleaning with subsequent exposure of the specimen to the laboratory air also resulted in a carbon-contaminated surface. This suggests that procedures of preparation of TEM specimens of steels outside an ultrahigh vacuum chamber are unlikely to result in the lowering of contamination rates on specimens to levels where measurements for carbon in the grain boundaries are possible. What is needed is a cleaning system as an integral part of the specimen insertion system into the field-emission scanning transmission electron microscope. This cleaning could be carried out by argon ion etching. Copyright (C) 2000 John Wiley & Sons, Ltd.

Differences in the post-translational modifications of human papillomavirus type 6b major capsid protein expressed from a baculovirus system compared with a vaccinia virus system

Virus-like particles (VLPs) are being currently investigated in vaccines against viral infections in humans. There are different recombinant-protein-expression systems available for obtaining the necessary VLP preparation for vaccination. However, the differences in post-translational modifications of the recombinant proteins obtained and their differences in efficacy in eliciting an anti-viral response in vaccines are not well established. In this study we have compared the posttranslational modifications of human papillomavirus type-6b major capsid protein L1 (HPV 6bL1) expressed using recombinant baculovirus (rBV) in Sf9 (Spodoptera frugiperda) insect cells, with the protein expressed using recombinant vaccinia virus (rVV) in CV-1 kidney epithelial cells, Two-dimensional gel electrophoresis of biosynthetically labelled rBV-expressed HPV 6bL1 showed several post-translationally modified variants of the protein, whereas rVV-expressed HPV 6bL1 showed only a few variants. Phosphorylations were detected at threonine and serine residues for the L1 expressed from rBV compared with phosphorylation at serine residues only for the L1 expressed from rVV. HPV 6bL1 expressed using rBV incorporated [H-3]mannose and [H-3]galactose, whereas HPV 6bL1 expressed using rVV incorporated only [H-3]galactose. We conclude that post-translational modification of recombinant HPV 6bL1 can differ according to the system used for its expression. Since recombinant L1 protein is a potential human-vaccine candidate, the implication of the observed differences in post-translational modifications on immunogenicity of L1 VLPs warrants investigation.

Identification of "pathologs" (disease-related genes) from the RIKEN mouse cDNA dataset using human curation plus FACTS, a new biological information extraction system

Background: A major goal in the post-genomic era is to identify and characterise disease susceptibility genes and to apply this knowledge to disease prevention and treatment. Rodents and humans have remarkably similar genomes and share closely related biochemical, physiological and pathological pathways. In this work we utilised the latest information on the mouse transcriptome as revealed by the RIKEN FANTOM2 project to identify novel human disease-related candidate genes. We define a new term patholog to mean a homolog of a human disease-related gene encoding a product ( transcript, anti-sense or protein) potentially relevant to disease. Rather than just focus on Mendelian inheritance, we applied the analysis to all potential pathologs regardless of their inheritance pattern. Results: Bioinformatic analysis and human curation of 60,770 RIKEN full-length mouse cDNA clones produced 2,578 sequences that showed similarity ( 70 - 85% identity) to known human-disease genes. Using a newly developed biological information extraction and annotation tool ( FACTS) in parallel with human expert analysis of 17,051 MEDLINE scientific abstracts we identified 182 novel potential pathologs. Of these, 36 were identified by computational tools only, 49 by human expert analysis only and 97 by both methods. These pathologs were related to neoplastic ( 53%), hereditary ( 24%), immunological ( 5%), cardio-vascular (4%), or other (14%), disorders. Conclusions: Large scale genome projects continue to produce a vast amount of data with potential application to the study of human disease. For this potential to be realised we need intelligent strategies for data categorisation and the ability to link sequence data with relevant literature. This paper demonstrates the power of combining human expert annotation with FACTS, a newly developed bioinformatics tool, to identify novel pathologs from within large-scale mouse transcript datasets.

Highly integrated and automated high-speed grinding system for printer heads constructed by combination materials

The fabrication of heavy-duty printer heads involves a great deal of grinding work. Previously in the printer manufacturing industry, four grinding procedures were manually conducted in four grinding machines, respectively. The productivity of the whole grinding process was low due to the long loading time. Also, the machine floor space occupation was large because of the four separate grinding machines. The manual operation also caused inconsistent quality. This paper reports the system and process development of a highly integrated and automated high-speed grinding system for printer heads. The developed system, which is believed to be the first of its kind, not only produces printer heads of consistently good quality, but also significantly reduces the cycle time and machine floor space occupation.

Role of galectin-1 in the olfactory nervous system

The olfactory nervous system is responsible for the detection of odors. Primary sensory olfactory neurons are located in a neuroepithelial sheet lining the nasal cavity. The axons from these neurons converge on to discrete loci or glomeruli in the olfactory bulb. Each glomerulus consists of the termination of thousands of primary axons on the dendrites of second-order olfactory neurons. What are the molecular mechanisms which guide growing olfactory axons to select sites in the olfactory bulb? We have shown that subpopulations of these axons differentially express cell surface carbohydrates and that these different subpopulations target and terminate in particular regions of the olfactory bulb. Interestingly, the olfactory neurons and glial components in the olfactory pathway between the nose and brain express galectin-1. By using in vitro assays of neurite outgrowth we found that both galectin-1 and it's ligands were capable of specifically stimulating neurite elongation. Examination of the olfactory system in galectin-1 null mutants revealed that a subpopulation of axons failed to navigate to their target site in the olfactory bulb. This is the first phenotypic effect observed in galectin-1 null mutants and indicates that galectin-1 has a role in the growth and/or guidance of a subpopulation of axons in the olfactory system during development.

Low-level lead exposure and children

The adverse effects of environmental lead exposure on the mental development of young children are well established. There is no safe level of blood lead below which children are not affected. Recent research expands our understanding of the impact of lead exposure continuing into later childhood, as well as its effects on children's behaviour. However, social and other environmental factors also contribute to variance in measures of developmental and behavioural outcomes. Lead is associated with only modest effects on children's development, but is a potentially modifiable risk factor. As environmental exposure to lead declines for the whole population, continued specific attention is needed for children living in industrial areas.

Embryonic development of the nervous system of the temnocephalid flatworm Craspedella pedum

The nervous system of temnocephalid flatworms consists of the brain and three pairs of longitudinal connectives extending into the trunk and tail. The connectives are crosslinked by an invariant number of regularly spaced commissures. Branches of the connectives innervate the tentacles of the head and the sucker organ in the tail. A set of nerve rings encircling the pharynx and connected to the brain and connectives constitute the pharyngeal nervous system. The nervous system is formed during early embryogenesis when the embryo represents a multilayered mesenchymal mass of cells. Gastrulation and the formation of separate epithelial germ layers that characterize most other animal groups are absent. The brain arises as a bilaterally symmetric condensation of postmitotic cells in the deep layers of the anterior region of the embryonic mesenchyme. The pattern of axon outgrowth, visualized by labeling with anti-acetylated tubulin (acTub) antibody, shows marked differences from the pattern observed in other flatworm taxa. in regard to the number of neurons that express the acTub epitope. Acetylated tubulin is only expressed in neurons that form long axon tracts. In other flatworm species, such as the typhloplanoid Mesostoma and the polyclad Imogine, which were investigated by us with the acTub antibody (Hartenstein and Ehlers [2000] Dev. Genes Evol. 210:399-415; Younossi-Hartenstein and Hartenstein [2000] Dev. Genes Evol. 210:383-398), only a small number of pioneer neurons become acTub positive during the embryonic period. By contrast, in temnocephalids, most, if not all, neurons express acTub and form long, large-diameter axons. Initially, the brain commissure, pharyngeal nerve ring, and the connectives are laid down. Commissural tracts and tentacle nerves branching off the connectives appear later. We speculate that the precocious differentiation of the nervous system may be related to the fact that temnocephalids move by muscle action, and possess a massive and complex muscular system when they hatch. In addition, they have muscular specializations such as the anterior tentacles and the posterior sucker that are used as soon as they hatch. By contrast, juveniles of Mesostoma and larvae of polyclads move predominantly by ciliary action that may not require a complex neural circuitry for coordination. (C) 2001 Wiley-Liss, Inc.

Tolerance or immunity to a tumor antigen expressed in somatic cells can be determined by systemic proinflammatory signals at the time of first antigen exposure

Mice transgenic for the E7 tumor Ag of human papillomavirus type 16, driven from a keratin 14 promoter, express E7 in keratinocytes but not dendritic cells. Grafted E7-transgenic skin is not rejected by E7-immunized mice that reject E7-transduced transplantable tumors. Rejection of recently transplanted E7-transgenic skin grafts, but not of control nontransgenic grafts or of established E7-transgenic grafts, is induced by systemic administration of live or killed Listeria monocytogenes or of endotoxin. Graft recipients that reject an E7 graft reject a subsequent E7 graft more rapidly and without further L. monocytogenes exposure, whereas recipients of an E7 graft given without L. monocytogenes do not reject a second graft, even if given with L. monocytogenes. Thus, cross-presentation of E7 from keratinocytes to the adaptive immune system occurs with or without a proinflammatory stimulus, but proinflammatory stimuli at the time of first cross-presentation of Ag can determine the nature of the immune response to the Ag. Furthermore, immune effector mechanisms responsible for rejection of epithelium expressing a tumor Ag in keratinocytes are different from those that reject an E7-expressing transplantable tumor. These observations have implications for immunotherapy for epithelial cancers.

Changes in zinc and copper homeostasis in human livers and kidneys associated with exposure to environmental cadmium

This study was undertaken to assess changes in zinc and copper homeostasis in human tissues that could be attributed to human exposure to environmental cadmium, using samples of lung, liver and kidney cortex of 61 Queensland residents, aged 2 to 89 years, who had died of accidental causes. None of the subjects were exposed to cadmium in the workplace. Levels of zinc in liver and kidney cortex samples showed inverse associations with donor age whereas zinc in lung only showed inverse association with gender. Lung zinc levels in females were 14% lower than in males. Zinc in liver and kidney cortex samples were found to exist in at least two pools; one was associated with cadmium that bound to metallothionein (MT) and the other was associated with non - MTbound copper. In liver, the amounts of zinc in the MT pool were smaller compared to those in non-MT pool given that only 7% of zinc variations were explained by cadmium whereas 22% of the liver zinc Variations were accounted for by non - MT bound copper. In sharp contrast, larger amounts of zinc in kidney cortex samples were in the MT pool, compared to those in the non-MT pool given that cadmium was found to explain 69% of total zinc variation whereas copper explained only 17% of kidney zinc variations. The levels of copper in liver were found to be increased by 45-50% in subjects with high cadmium exposure level, compared to subjects of similar ages with medium exposure level. The levels of zinc and copper in kidney cortex samples in the subjects with high cadmium exposure were both found to be significantly elevated compared to those found in the medium-exposure group whereas copper contents were about 19-23% greater than in medium- as well as low-exposure groups. Taken together these results indicate increased sequestration of zinc and copper in liver and kidney cortex samples. The increases in metal sequestrations were observed in liver samples having cadmium contents of greater than 1 mug/g wet weight and in kidney cortex having cadmium contents of greater than 26 mug/g wet weight. Zinc and copper contents in lung of this sample group, however, were not associated with cadmium due probably to lower exposure levels compared to those of liver and kidney.