Interleukin-5-mediated allergic airway inflammation inhibits the human surfactant protein C promoter in transgenic mice

Allergen challenge in the lung of humans and animals is associated with surfactant dysfunction, but the mechanism of this effect has not been established. By using a murine model of asthma we now report the effect of allergen-induced airway inflammation on the expression of transgenes regulated by the human surfactant protein (hSP)-C promoter. The hSP-C 3.7-kilobase pair promoter was used to direct the expression of eotaxin, an eosinophil-selective chemokine, into the lungs of several transgenic lines. As expected, the transgenic mice expressed increased amounts of eotaxin mRNA and protein compared with wild-type mice. Surprisingly, following allergen challenge, there was a marked down-regulation of transgene mRNA in three independent transgenic lines. The down-regulation was in contrast to other related proteins such as endogenous eotaxin and surfactant protein D levels, which were both increased following allergen challenge. Consistent with specific down-regulation of the eotaxin transgene, there was no increase in pulmonary eosinophil levels in the transgenic mice above that found in wild-type mice. Analysis of hSP-C transgenic mice with distinct reporter genes and 3'-untranslated regions revealed that allergen challenge was directly affecting the hSP-C promoter. We hypothesized that allergen-induced down-regulation of the hSP-C promoter was related to the eosinophilic inflammation. To test this, we blocked eosinophilic inflammation in the lungs by treating mice with neutralizing antiserum against interleukin-5. Interestingly, this treatment also blocked allergen-induced inhibition of the hSP-C promoter. These results establish that allergic airway inflammation is associated with up-regulation of the surfactant proteins primarily involved in immunity, whereas down-regulation of the surfactant protein primarily involved in maintaining airway patency. Furthermore, the marked down-regulation of the hSP-C promoter is interleukin-5-dependent, implying a critical role for eosinophilic inflammation. These results suggest that alterations in surfactant protein levels may contribute to immune and airway dysfunction in asthma.     

Venezuelan equine encephalomyelitis virus structure and its divergence from old world alphaviruses

Although alphaviruses have been extensively studied as model systems for the structural organization of enveloped viruses, no structures exist for the phylogenetically distinct eastern equine encephalomyelitis (EEE)-Venezuelan equine encephalomyelitis (VEE) lineage of New World alphaviruses. Here we report the 25-A structure of VEE virus, obtained from electron cryomicroscopy and image reconstruction. The envelope spike glycoproteins of VEE virus have a T=4 icosahedral arrangement, similar to that observed in Old World Sindbis, Semliki Forest, and Ross River alphaviruses. However, VEE virus has pronounced differences in its nucleocapsid structure relative to nucleocapsid structures repeatedly observed in Old World alphaviruses.     

Substitution rates of organelle and nuclear genes in sharks: implicating metabolic rate (again)

Rates of nucleotide substitution for nuclear genes are thought to be governed primarily by the number of germ line replication events (the so-called "generation time" hypothesis). In contrast, rates of mitochondrial DNA evolution appear to be set primarily by DNA damage pathways of mutation mediated by mutagenic by-products of oxidative phosphorylation (the so-called "metabolic-rate" hypothesis). Comparison of synonymous substitution rates estimated for the mitochondrial cytochrome b gene and nuclear-encoded dlx, hsp70, and RAG-1 genes in mammals and sharks shows that rates of molecular evolution for sharks are approximately an order of magnitude slower than those for mammals for both nuclear and mitochondrial genes. In addition, there is significant positive covariation of substitution rate for mitochondrial and nuclear genes within sharks. These results, interpreted in light of the pervasiveness of DNA damage by mutagenic by-products of oxygen metabolism to both nuclear and mitochondrial genes and coupled with increasing evidence for cross-genome activity of DNA repair enzymes, suggest that molecular clocks for mitochondrial and nuclear genes may be set primarily by common mutational mechanisms.      

The iceman under pressure (Part I): A description of skull deformations due to 5100 years of glacial action

Due to its long deposition in the glacier, the 'Iceman' (an ice-mummy from the Hauslabjoch) has been deformed, notably its skull. We introduce various comparative methods that describe these deformations, assuming they can be ascribed--to a large extent--to glacial action. While pressure is a scalar, the deformations must be described via a 2-tensor strain field (which can be represented by a matrix function value at every point throughout the skull). In this paper, we present the assumed deformations in numerous graphical forms and, furthermore, the limitations in interpretation--including an estimate of statistical variability--that can be revealed by this analysis. These methods, although describing the results of glacial action and implying a 2-tensor strain field (which will be presented in a subsequent paper), do not permit a straightforward reconstruction of the original, underformed skull. These methods have wider applications to the general problem of deformation.     

Response to social challenge in young bonnet (Macaca radiata) and pigtail (Macaca nemestrina) macaques is related to early maternal experiences

Previous experience affects how young primates respond to challenging social situations. The present retrospective study looked at one aspect of early experience, the quality of the mother-infant relationship, to determine its relationship to young bonnet and pigtail macaques' responses to two social challenges: temporary maternal separation at 5-6 months and permanent transfer to an unfamiliar peer group at 16-17 months. Relationship quality was measured quantitatively on 30 macaque mother-infant pairs with the Relationship Quality Index (RQI), the ratio of relative affiliation to relative agonism as previously applied to capuchin monkeys. Infants with high RQI values had amicable mother-infant relationships and infants with low RQI values had agonistic mother-infant relationships. Young monkeys with amicable and agonistic relationships showed consistent differences in behavior before, during, and after each social challenge, supporting the hypothesis that juveniles from amicable mother-infant relationships based on the RQI coped more effectively with social challenges than did juveniles from agonistic mother-infant relationships. Results suggest 1) characteristic amicability or agonism in early mother-offspring macaque relationships has the potential to influence offspring behavior in tense social contexts and 2) the RQI is useful as one of a coordinated suite of methods for studying the development of social skills.     

Sleep rhythmicity and homeostasis in mice with targeted disruption of mPeriod genes

In mammals, sleep is regulated by circadian and homeostatic mechanisms. The circadian component, residing in the suprachiasmatic nucleus (SCN), regulates the timing of sleep, whereas homeostatic factors determine the amount of sleep. It is believed that these two processes regulating sleep are independent because sleep amount is unchanged after SCN lesions. However, because such lesions necessarily damage neuronal connectivity, it is preferable to investigate this question in a genetic model that overcomes the confounding influence of circadian rhythmicity. Mice with disruption of both mouse Period genes (mPer)1 and mPer2 have a robust diurnal sleep-wake rhythm in an entrained light-dark cycle but lose rhythmicity in a free-run condition. Here, we examine the role of the mPer genes on the rhythmic and homeostatic regulation of sleep. In entrained conditions, when averaged over the 24-h period, there were no significant differences in waking, slow-wave sleep (SWS), or rapid eye movement (REM) sleep between mPer1, mPer2, mPer3, mPer1-mPer2 double-mutant, and wild-type mice. The mice were then kept awake for 6 h (light period 6-12), and the mPer mutants exhibited increased sleep drive, indicating an intact sleep homeostatic response in the absence of the mPer genes. In free-run conditions (constant darkness), the mPer1-mPer2 double mutants became arrhythmic, but they continued to maintain their sleep levels even after 36 days in free-running conditions. Although mPer1 and mPer2 represent key elements of the molecular clock in the SCN, they are not required for homeostatic regulation of the daily amounts of waking, SWS, or REM sleep.     

A thallium-sensitive, fluorescence-based assay for detecting and characterizing potassium channel modulators in mammalian cells

Potassium channels have been identified as targets for a large number of therapeutic indications. The ability to use a high-throughput functional assay for the detection and characterization of small-molecule modulators of potassium channels is very desirable. However, present techniques capable of screening very large chemical libraries are limited in terms of data quality, temporal resolution, ease of use, and requirements for specialized instrumentation. To address these issues, the authors have developed a fluorescence-based thallium flux assay. This assay is capable of detecting modulators of both voltage and ligand-gated potassium channels expressed in mammalian cells. The thallium flux assay can use instruments standard to most high-throughput screening laboratories, and using such equipment has been successfully employed to screen large chemical libraries consisting of hundreds of thousands of compounds.     

Clinical and cytogenetic manifestations of subtelomeric aberrations: Report of six cases

BACKGROUND: Fluorescent subtelomeric probes for the 41 different subtelomeric regions (the p arms of the acrocentric chromosomes were excluded) have been developed over the last 10 years. These probes can detect deletions, duplications, and translocations in the gene-rich subtelomeric regions of human chromosomes, regions where crossing over frequently occurs and where a high number of abnormalities have been found. Recently, commercially produced probes have become available, which has led to the detection of subtelomeric abnormalities in 7.4% of patients with moderate to severe mental retardation (Knight et al., 1999). CASES: We evaluated 43 dysmorphic children with developmental delay and/or mental retardation of unknown etiology and/or autism who were previously assessed for chromosome abnormalities, metabolic disorders, or recognizable dysmorphic syndromes, all of which were ruled out. Of the 43 children tested, 6 (14%) were found to have subtelomeric aberrations. CONCLUSIONS: We recommend that patients with dysmorphic features and mental retardation of unknown etiology who also have a normal standard chromosome analysis should have subtelomeric FISH testing performed earlier in their clinical workup.