Legionella pneumophila inhibits type I interferon signaling to avoid cell-intrinsic host cell defense

The host type I interferon (IFN) response protects against Legionella pneumophila infections. Other bacterial pathogens inhibit type I IFN-mediated cell signaling; however, the interaction between this signaling pathway and L. pneumophila has not been well described. Here, we demonstrate that L. pneumophila inhibits the IFN-β signaling pathway but does not inhibit IFN-γ-mediated cell signaling. The addition of IFN-β to L. pneumophila-infected macrophages limited bacterial growth independently of NOS2 and reactive nitrogen species. The type IV secretion system of L. pneumophila is required to inhibit IFN-β-mediated cell signaling. Finally, we show that the inhibition of the IFN-β signaling pathway occurs downstream of STAT1 and STAT2 phosphorylation. In conclusion, our findings describe a novel host cell signaling pathway inhibited by L. pneumophila via its type IV secretion system.

Use of zinc deposited in deciduous teeth as a retrospective measurement of dietary zinc exposure during early development

Purpose

We proposed that zinc (Zn) deposition in deciduous teeth would be a timed record of exposure to this essential micronutrient over very early life. We tested this hypothesis by gathering information on the maternal and child's diet during pregnancy and early infancy and measuring mineral deposition in the dentine at points during deciduous tooth development.

Methods

We developed a short food frequency questionnaire (S-FFQ) to record consumption of food containing Zn during pregnancy and over the first year of life of the child in an Indonesian population. Zn, Sr and Ca were measured by laser ablation ICP-MS in a series of points across the developmental timeline in deciduous teeth extracted from 18 children undergoing the process as part of dental treatment whose mothers completed the SFFQ. Mothers and children were classified into either high Zn or low Zn groups according to calculated daily Zn intake.

Results

The Zn/Sr ratio in dentine deposited over late pregnancy and 0-3 months post-partum was higher (p < 0.001, 2-way ANOVA; p < 0.05 by Holm-Sidak post hoc test) in the teeth of children of mothers classified as high Zn consumers (n = 10) than in children of mothers classified as low Zn consumers (n = 8).

Conclusion

The S-FFQ was validated internally as adequately accurate to measure zinc intake retrospectively during pregnancy and post-partum (∼7 years prior) by virtue of the correlation with measurements of zinc in deciduous teeth. The ratio of Zn/Sr in deciduous teeth appears to be a biomarker of exposure to zinc nutrition during early development and offers promise for use as a record of prior exposure along a timeline for research studies and, potentially, to identify individuals at heightened risk of detrimental impacts of poor early life zinc nutrition on health in later life and to implement preventative interventions.

Pseudophosphatase MK-STYX Alters Histone Deacetylase 6 Cytoplasmic Localization, Decreases Its Phosphorylation, and Increases Detyrosination of Tubulin

The catalytically inactive mitogen-activated protein (MAP) kinase phosphatase, MK-STYX (MAPK (mitogen-activated protein kinase) phosphoserine/threonine/tyrosine-binding protein) interacts with the stress granule nucleator G3BP-1 (Ras-GAP (GTPase-activating protein) SH3 (Src homology 3) domain-binding protein-1), and decreases stress granule (stalled mRNA) formation. Histone deacetylase isoform 6 (HDAC6) also binds G3BP-1 and serves as a major component of stress granules. The discovery that MK-STYX and HDAC6 both interact with G3BP-1 led us to investigate the effects of MK-STYX on HDAC6 dynamics. In control HEK/293 cells, HDAC6 was cytosolic, as expected, and formed aggregates under conditions of stress. In contrast, in cells overexpressing MK-STYX, HDAC6 was both nuclear and cytosolic and the number of stress-induced aggregates significantly decreased. Immunoblots showed that MK-STYX decreases HDAC6 serine phosphorylation, protein tyrosine phosphorylation, and lysine acetylation. HDAC6 is known to regulate microtubule dynamics to form aggregates. MK-STYX did not affect the organization of microtubules, but did affect their post-translational modification. Tubulin acetylation was increased in the presence of MK-STYX. In addition, the detyrosination of tubulin was significantly increased in the presence of MK-STYX. These findings show that MK-STYX decreases the number of HDAC6-containing aggregates and alters their localization, sustains microtubule acetylation, and increases detyrosination of microtubules, implicating MK-STYX as a signaling molecule in HDAC6 activity.

Mycobacterium tuberculosis Inhibits Autocrine Type I IFN Signaling to Increase Intracellular Survival

The type I IFNs (IFN-α and -β) are important for host defense against viral infections. In contrast, their role in defense against nonviral pathogens is more ambiguous. In this article, we report that IFN-β signaling in murine bone marrow-derived macrophages has a cell-intrinsic protective capacity against Mycobacterium tuberculosis via the increased production of NO. The antimycobacterial effects of type I IFNs were mediated by direct signaling through the IFN-α/β-receptor (IFNAR), as Ab-mediated blocking of IFNAR1 prevented the production of NO. Furthermore, M. tuberculosis is able to inhibit IFNAR-mediated cell signaling and the subsequent transcription of 309 IFN-β-stimulated genes in a dose-dependent way. The molecular mechanism of inhibition by M. tuberculosis involves reduced phosphorylation of the IFNAR-associated protein kinases JAK1 and TYK2, leading to reduced phosphorylation of the downstream targets STAT1 and STAT2. Transwell experiments demonstrated that the M. tuberculosis-mediated inhibition of type I IFN signaling was restricted to infected cells. Overall, our study supports the novel concept that M. tuberculosis evolved to inhibit autocrine type I IFN signaling to evade host defense mechanisms.

MK-STYX Alters the Morphology of Primary Neurons, and Outgrowths in MK-STYX Overexpressing PC-12 Cells Develop a Neuronal Phenotype

We previously reported that the pseudophosphatase MK-STYX (mitogen activated kinase phosphoserine/threonine/tyrosine binding protein) dramatically increases the number of what appeared to be primary neurites in rat pheochromocytoma (PC-12) cells; however, the question remained whether these MK-STYX-induced outgrowths were bona fide neurites, and formed synapses. Here, we report that microtubules and microfilaments, components of the cytoskeleton that are involved in the formation of neurites, are present in MK-STYX-induced outgrowths. In addition, in response to nerve growth factor (NGF), MK-STYX-expressing cells produced more growth cones than non-MK-STYX-expressing cells, further supporting a model in which MK-STYX has a role in actin signaling. Furthermore, immunoblot analysis demonstrates that MK-STYX modulates actin expression. Transmission electron microscopy confirmed that MK-STYX-induced neurites form synapses. To determine whether these MK-STYX-induced neurites have pre-synaptic or post-synaptic properties, we used classical markers for axons and dendrites, Tau-1 and MAP2 (microtubule associated protein 2), respectively. MK-STYX induced neurites were dopaminergic and expression of both Tau-1 and MAP2 suggests that they have both axonal and dendritic properties. Further studies in rat hippocampal primary neurons demonstrated that MK-STYX altered their morphology. A significant number of primary neurons in the presence of MK-STYX had more than the normal number of primary neurites. Our data illustrate the novel findings that MK-STYX induces outgrowths in PC-12 cells that fit the criteria for neurites, have a greater number of growth cones, form synapses, and have pre-synaptic and post-synaptic properties. It also highlights that the pseudophosphatase MK-STYX significantly alters the morphology of primary neurons.

Radiation therapy port films: a quality assurance study

PURPOSE

The purpose of this study was to assess the port film acceptance rate in a large community practice setting and to catalog the reasons for rejection.

METHODS

Between December 1993 and July 1996, a quality assurance monitor log was maintained on 4,150 patients who underwent a total of 4,450 treatment courses. Port films were taken at the beginning and at the half way point in the treatment course. A total of 20,735 port films were compared with the matching simulation films. We recorded the site being treated, the radiation oncologist who reviewed the films and the reason for rejection.

RESULTS

The monthly acceptance rate varied from a low of 67% to a high of 83%, with a gradual upward trend. The single most common reason for rejecting films was a centering problem-12% of all films taken were rejected for this reason. The next most common problems were block placement or body setup errors that caused 3.4% and 2.7% of the films to be rejected, respectively. Average acceptance rates between 10 different sites (abdomen, brain, breast, chest, extremities, head and neck, pelvis, prostate, rectum and spine) varied from 68% to 80%. Individual differences between 12 radiation oncologists reviewing the films varied from 67% to 87%.

CONCLUSIONS

A detailed analysis of field localization errors allowed us to identify areas where improvement was needed and suggested that specific guidelines for acceptance would help reduce the variability noted in the acceptance rate between sites and physicians.

The economics of death? A descriptive study of the impact of funeral and cremation costs on U.S. households

The death-care industry in the United States has been virtually ignored by policy makers. Although the industry is highly fragmented, pricing is becoming increasingly influenced by multinational corporations. This fact coupled with the market structure for services, consumers' preferences, and the attributes of death-care services, has resulted in average funeral cost of over $5,000 per deceased. This figure is over 25 percent higher than the average annual family welfare payment in the United States. As estimated in this paper, the distributional effects of a death occurring within a household varies significantly by income as well as race and ethnicity. The author concludes that Americans should engage more openly in the discussion of death, increase their rate of prearrangements, and seek alternatives to the traditional funeral.

Quinpirole inhibits striatal and excites pallidal neurons in freely moving rats

The activity of single neurons in the striatum of freely moving rats was recorded in response to systemic administration of dopamine agonists selective for either the D1 or D2 family of receptors. At a dose that induced behavioral activation, SKF-38393 (5.0 mg/kg s.c.), a D1 agonist, had no consistent effect on striatal activity, whereas quinpirole (1.0-5.0 mg/kg s.c.), a D2 agonist, inhibited the great majority of striatal neurons. In addition, quinpirole (1.0 mg/kg s.c.) excited neurons of the globus pallidus, which receives an inhibitory projection from the striatum. These results are consistent with models of the basal ganglia in which dopamine, via D2 receptors, inhibits striatopallidal activity, resulting in a disinhibition of neurons in globus pallidus.

Telomeres, cancer, and aging. Altering the human life span

Population projections of the aging global society and its fiscal and social impact have depended on assumptions regarding the human life span. Until now, the assumption that the maximum human life span is fixed has been justified. Recent advances in cell biology, genetics, and our understanding of the cellular processes that underlie aging, however, have shown that this assumption is invalid in a number of animal models and suggest that this assumption may become invalid for humans as well. In vitro alteration of telomeres affects cellular senescence, and in vivo manipulation of genes and diet can increase maximum life span in animal models if these discoveries are extended to humans. We may soon be able to extend the maximum human life span and postpone or prevent the onset of diseases associated with aging. Such a possibility requires that we recognize a growing uncertainty in any attempt to project international health care costs into the next few decades. The costs may be significantly lower than projections, if life span increases and age-related disabilities are postponed or less severe, or perhaps higher, if life span increases without altering the onset and severity of disability. An appropriate uncertainty regarding the human life span undermines any attempt to accurately predict health costs in the next century.

Uncompensated hospital care: charitable mission or profitable business decision?

Provision of hospital uncompensated care is generally assumed to be adversely affected as increased healthcare competition decreases demand for compensated hospital services. Economic theory, however, suggests the question is more complex. Non-profit hospitals are assumed in this paper to maximize utility as a function of uncompensated care, subject to the constraint that revenues cover costs. For-profit hospitals, in contrast, are assumed to maximize profit while recognizing that failure to meet community expectations regarding provision of uncompensated care could negatively impact profits. Therefore, for-profit hospital supply of uncompensated care focuses on balancing the hospital's marginal costs and marginal benefits. These models predict that non-profit hospitals will respond to increased competition by reducing the supply of uncompensated care. In contrast, for-profit hospitals will increase the supply of uncompensated care when market demand decreases since the concurrent decrease in compensated care reduces the marginal cost of producing uncompensated care. The models also predict that for-profit hospitals will respond to changes in community expectations regarding the provision of uncompensated care.

Uncompensated hospital care: charitable mission or profitable business decision?

Provision of hospital uncompensated care is generally assumed to be adversely affected as increased healthcare competition decreases demand for compensated hospital services. Economic theory, however, suggests the question is more complex. Non-profit hospitals are assumed in this paper to maximize utility as a function of uncompensated care, subject to the constraint that revenues cover costs. For-profit hospitals, in contrast, are assumed to maximize profit while recognizing that failure to meet community expectations regarding provision of uncompensated care could negatively impact profits. Therefore, for-profit hospital supply of uncompensated care focuses on balancing the hospital's marginal costs and marginal benefits. These models predict that non-profit hospitals will respond to increased competition by reducing the supply of uncompensated care. In contrast, for-profit hospitals will increase the supply of uncompensated care when market demand decreases since the concurrent decrease in compensated care reduces the marginal cost of producing uncompensated care. The models also predict that for-profit hospitals will respond to changes in community expectations regarding the provision of uncompensated care.

The economic attributes of medical care: implications for rationing choices in the United States and United Kingdom

The healthcare systems of the United States and United Kingdom are vastly different. The former relies primarily on private sector incentives and market forces to allocate medical care services, while the latter is a centrally planned system funded almost entirely by the public sector. Therefore, each nation represents divergent views on the relative efficacy of the market or government in achieving social objectives in the area of medical care policy. Since its inception in 1948, the National Health Services (NHS) of the United Kingdom has consistently emphasized equity in the allocation of medical services. It has done so by creating a system whereby services are universally free of charge at the point of entry. Conversely, the United States has relied upon the evolution of a perplexing array of public and private sector insurance schemes centered more around consumer choice than equity in allocation.

Phencyclidine-induced increases in striatal neuron firing in behaving rats: reversal by haloperidol and clozapine

Amphetamine and related drugs of abuse facilitate dopamine transmission in the striatum. This action is believed to underlie the increase in firing of striatal motor-related neurons after amphetamine administration in behaving rats. The present study extended this electrophysiological investigation to phencyclidine (PCP), a nonamphetamine psychomotor stimulant that acts primarily as a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) glutamate receptors. Like amphetamine, PCP (1.0, 2.5, or 5.0 mg/kg) increased the activity of striatal motor-related neurons concomitant with behavioral activation. These effects were blocked by subsequent administration of either 1.0 mg/kg haloperidol or 20.0 mg/kg clozapine, typical and atypical neuroleptics, respectively. Dizocilpine (MK- 801), another noncompetitive NMDA antagonist, mimicked the effect of PCP. Collectively, these results indicate that amphetamine and NMDA antagonists exert comparable effects on striatal motor-related neurons, suggesting that the response of these cells to psychomotor stimulants is regulated by a dopaminergic-glutamatergic influence.

Induction of new carbonic anhydrase II following treatment with acetazolamide in DBA and C57 mice

The mechanism by which animals develop tolerance to the antiepileptic effects of the carbonic anhydrase (CA) inhibitor, acetazolamide, was explored using a quantitative immunocytochemical method. Cerebral cortex sections of DBA/2J mice susceptible to audiogenic seizures and of C57BL/6J nonsusceptible mice were stained with antibody to mouse CA II in controls and following treatment with acetazolamide (40 and 200 mg/kg) for 1, 3, and 5 days. The percentage increases in CA II fluorescent intensity of cells from C57 mice treated with 40 and 200 mg/kg acetazolamide over those of untreated mice were 22 and 36%, respectively, after 1 day, 32 and 40%, respectively, after 3 days, and 17 and 40%, respectively, after 5 days of treatment. The corresponding percentage increases in fluorescent intensity of cells from DBA mice over controls were 13 and 32%, respectively, after 1 day, 17 and 41%, respectively, after 3 days, and 26 and 58%, respectively, after 5 days of treatment. The fluorescent intensity of cells from untreated DBA mice was 35% greater than those of untreated C57 mice. In C57 mice the maximum amount of CA II per cell at each dose occurred 24 h after acetazolamide treatment, whereas the amount in DBA mice continued to increase with time and dose up to 5 days. The differences between the two strains can be explained by changes in distribution of CA II to subcellular locations or by defects in phosphorylation of the molecule.