Malaria transmission potential could be reduced with current and future climate change.

Several studies suggest the potential for climate change to increase malaria incidence in cooler, marginal transmission environments. However, the effect of increasing temperature in warmer regions where conditions currently support endemic transmission has received less attention. We investigate how increases in temperature from optimal conditions (27 °C to 30 °C and 33 °C) interact with realistic diurnal temperature ranges (DTR: ± 0 °C, 3 °C, and 4.5 °C) to affect the ability of key vector species from Africa and Asia (Anopheles gambiae and An. stephensi) to transmit the human malaria parasite, Plasmodium falciparum. The effects of increasing temperature and DTR on parasite prevalence, parasite intensity, and mosquito mortality decreased overall vectorial capacity for both mosquito species. Increases of 3 °C from 27 °C reduced vectorial capacity by 51-89% depending on species and DTR, with increases in DTR alone potentially halving transmission. At 33 °C, transmission potential was further reduced for An. stephensi and blocked completely in An. gambiae. These results suggest that small shifts in temperature could play a substantial role in malaria transmission dynamics, yet few empirical or modeling studies consider such effects. They further suggest that rather than increase risk, current and future warming could reduce transmission potential in existing high transmission settings.

Utility of diffusion tensor imaging in evaluation of the peritumoral region in patients with primary and metastatic brain tumors.

In the brain, diffusion tensor imaging is a useful tool for defining white matter anatomy, planning a surgical approach to space-occupying lesions, and characterizing tumors, including distinguishing primary tumors from metastases. Recent studies have attempted, with varying success, to use DTI to define the extent of tumor microinfiltration beyond the apparent borders on T2-weighted imaging. In the present review, we discuss the current state of research on the utility of DTI for evaluating the peritumoral region of brain tumors.

Glucocorticoid receptor dimerization is required for proper recovery of LPS-induced inflammation, sickness behavior and metabolism in mice.

Endogenous glucocorticoids are essential for mobilizing energy resources, restraining inflammatory responses and coordinating behavior to an immune challenge. Impaired glucocorticoid receptor (GR) function has been associated with impaired metabolic processes, enhanced inflammation and exaggerated sickness and depressive-like behaviors. To discern the molecular mechanisms underlying GR regulation of physiologic and behavioral responses to a systemic immune challenge, GR(dim) mice, in which absent GR dimerization leads to impaired GR-DNA-binding-dependent mechanisms but intact GR protein-protein interactions, were administered low-dose lipopolysaccharide (LPS). GR(dim)-LPS mice exhibited elevated and prolonged levels of plasma corticosterone (CORT), interleukin (IL)-6 and IL-10 (but not plasma tumor necrosis factor-α (TNFα)), enhanced early expression of brain TNFα, IL-1ß and IL-6 mRNA levels, and impaired later central TNFα mRNA expression. Exaggerated sickness behavior (lethargy, piloerection, ptosis) in the GR(dim)-LPS mice was associated with increased early brain proinflammatory cytokine expression and late plasma CORT levels, but decreased late brain TNFα expression. GR(dim)-LPS mice also exhibited sustained locomotor impairment in the open field, body weight loss and metabolic alterations measured by indirect calorimetry, as well as impaired thermoregulation. Taken together, these data indicate that GR dimerization-dependent DNA-binding mechanisms differentially regulate systemic and central cytokine expression in a cytokine- and time-specific manner, and are essential for the proper regulation and recovery of multiple physiologic responses to low-dose endotoxin. Moreover, these results support the concept that GR protein-protein interactions are not sufficient for glucocorticoids to exert their full anti-inflammatory effects and suggest that glucocorticoid responses limited to GR monomer-mediated transcriptional effects could predispose individuals to prolonged behavioral and metabolic sequelae of an enhanced inflammatory state.

Progesterone regulation of uterine dendritic cell function in rodents is dependent on the stage of estrous cycle.

Steroid hormones, such as progesterone, are able to modify immunity and influence disease outcome. Dendritic cells (DCs) drive potent immune responses, express receptors for steroid hormones, and may be a primary target of steroid hormone actions during infection of the genital tract, including uterine tissue. Here, we report that progesterone limited DC-associated activation marker expression and inhibited cytokine secretion by uterine DCs, which was associated with changes in signal transducer and activator of transcription 1 (STAT1) activity. We also found that DCs from mice at stages with higher progesterone concentrations (diestrus, metaestrus) were more sensitive to progesterone than those in stages with lower progesterone concentrations (proestrus, estrus), both in vitro and in vivo. This difference correlated with the levels of progesterone receptor expressed by DCs. These data suggest that progesterone regulates DC function and could contribute to the susceptibility of females to uterine and other genital tract infections at selected time periods throughout the life cycle.

Effects of dexamethasone on rat dendritic cell function.

Glucocorticoids have been reported to affect immunity at varying concentrations. While glucocorticoids have shown profound effects on innate immunity, their effects on rat dendritic cells have not been fully examined. In this study, we evaluated the effects of the synthetic glucocorticoid dexamethasone on cultured rat dendritic cells (DCs) from spleen and derived from bone marrow cells to determine whether responsiveness to dexamethasone varies between DCs from different organ sites. Cells were analyzed for expression of glucocorticoid receptor (GR), the primary receptor through which dexamethasone exerts its effects and was found to be primarily located in the cytoplasm of immature DCs. Bone marrow-derived DCs showed more sensitivity to dexamethasone treatment compared to splenic DCs. Dexamethasone treatment of LPS-matured DCs had profound dose-dependent effects on cytokine production. Dexamethasone treatment also led to a dose-dependent downregulation of expression of costimulatory molecules by mature DCs. Dexamethasone modified immature DC uptake of antigen (FITC-Dextran), with slightly higher numbers of splenic DCs taking up antigen compared to bone marrow-derived DCs. These data suggest that dexamethasone is able to similarly affect both bone marrow-derived and splenic DC function at the immature and mature DC states and could contribute to exacerbation of infection by hindering DC-mediated immune responses.

Brain-immune interactions and disease susceptibility.

Many studies have established the routes by which the immune and central nervous (CNS) systems communicate. This network of connections permits the CNS to regulate the immune system through both neuroendocrine and neuronal pathways. In turn, the immune system signals the CNS through neuronal and humoral routes, via immune mediators and cytokines. This regulatory system between the immune system and CNS plays an important role in susceptibility and resistance to autoimmune, inflammatory, infectious and allergic diseases. This review focuses on the regulation of the immune system via the neuroendocrine system, and underlines the link between neuroendocrine dysregulation and development of major depressive disorders, autoimmune diseases and osteoporosis.

Different approaches to understanding autoimmune rheumatic diseases: the neuroimmunoendocrine system.

Rheumatic autoimmune diseases are characterized by dysregulation of the immune response that leads to inflammation, pain, disease and stiffness and have been shown to have differences in disease pattern, depending on the gender and age of an individual. The majority of these conditions predominantly affect females of all species and also show increased severity of disease in female animal models. In addition to the gender differences in disease development, persons are often more susceptible at specific stages of life. This review will discuss some of the data indicating age and gender differences in development of these diseases and will review hormonal and other factors that may contribute to disease expression and severity.

Lipopolysaccharide-induced oestrogen receptor regulation in the paraventricular hypothalamic nucleus of lewis and Fischer rats.

Oestrogen receptor (ER) regulation of gene transcription in neurosecretory and pituitary cells has been proposed as an important mechanism for increased hypothalamic-pituitary-adrenal (HPA) axis responses in females of several mammalian species, including humans. Inbred female Fischer (F344/N) and Lewis (LEW/N) rats have similar oestrogen levels, although Fischer rats exhibit hyper- and Lewis rats hypo-HPA axis responses. The blunted HPA axis response of Lewis rats has been associated with their blunted hypothalamic corticotropin releasing hormone (CRH) expression. To determine if the female CRH expression deficiency in Lewis rats is associated with defective ER expression and regulation, hypothalamic paraventricular nucleus (PVN) transcript levels of CRH and ER were determined under basal conditions and after immune challenge. Microdissected PVN were obtained from control and lipopolysaccharide (LPS) treated Lewis and Fischer rats and CRH, ERalpha and beta mRNA levels were determined by semiquantitative reverse-transcriptase-polymerase chain reaction. In addition, ERalpha and beta protein levels were determined by semiquantitative Western blots. ERalpha and beta mRNA and protein levels in the PVN of control Fischer rats were significantly higher than in control Lewis rats. ERalpha and beta mRNA and protein levels in Fischer rats were reduced by LPS administration at the time of maximal CRH mRNA levels but did not change in Lewis rats, an effect independent of oestrogen levels. These data indicate that defective neuroendocrine HPA axis responses are associated with defective ER expression and regulation in Lewis PVN despite oestrogen concentrations.

Marked suppression of gastric ulcerogenesis and intestinal responses to stress by a novel class of drugs.

When exposed to prolonged stress, rats develop gastric ulceration, enhanced colon motility with depletion of its mucin content and signs of physiological and behavioral arousal. In this model, we tested whether antidepressants (fluoxetine and bupropion), anxiolytics (diazepam and buspirone) or the novel nonpeptide corticotropin-releasing hormone (CRH) type-1 receptor (CRH-R1) antagonist, antalarmin, modify these responses. Fluoxetine, bupropion, diazepam and antalarmin all suppressed stress-induced gastric ulceration in male Sprague-Dawley rats exposed to four hours of plain immobilization. Antalarmin produced the most pronounced anti-ulcer effect and additionally suppressed the stress-induced colonic hypermotility, mucin depletion, autonomic hyperarousal and struggling behavior. Intraperitoneal CRH administration reproduced the intestinal but not the gastric responses to stress while vagotomy antagonized the stress-induced gastric ulceration but not the intestinal responses. We conclude that brain CRH-R1 and vagal pathways are essential for gastric ulceration to occur in response to stress and that peripheral CRH-R1 mediates colonic hypermotility and mucin depletion in this model. Nonpeptide CRH-R1 antagonists may therefore be prophylactic against stress ulcer in the critically ill and therapeutic for other pathogenetically related gastrointestinal disorders such as peptic ulcer disease and irritable bowel syndrome.

IL-1 receptor type I gene expression in the amygdala of inflammatory susceptible Lewis and inflammatory resistant Fischer rats.

Lewis (LEW/N) and Fischer (F344/N) rats have different responses to inflammatory and behavioral stressors due to differences in hypothalamus-pituitary-adrenal (HPA) axis function. For example, LEW/N rats are more sensitive to restraint, inflammation and experimentally induced autoimmunity due to decreased HPA activity. The HPA axis response to peripheral inflammation is mediated, at least in part, by IL-1beta and its receptor, IL-1 type I (IL-1RI). Here, we studied the distribution of IL-1RI mRNA in the brains of LEW/N and F344/N rats, and demonstrated that IL-1RI mRNA expression has significantly increased in the basolateral nucleus (BLA) of the amygdala of LEW/N rats. These findings suggest that strain-specific HPA axis responses may be mediated by extrahypothalamic pathways.

A human glucocorticoid receptor gene variant that increases the stability of the glucocorticoid receptor beta-isoform mRNA is associated with rheumatoid arthritis.

OBJECTIVE: To study the occurrence and function of polymorphism in the human glucocorticoid receptor (hGR) gene in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). METHODS: We used single stranded conformation polymorphism (SSCP) and direct sequencing to study the hGR gene in 30 patients with RA, 40 with SLE, and 24 controls. A newly identified polymorphism was transfected in COS-1 cells and the stability of the mRNA containing the polymorphism was tested using real-time PCR. RESULTS: A polymorphism in the hGR gene in exon9beta, in an "ATTTA" motif, was found to be significantly associated with RA. Introduction of this polymorphism in the hGRb mRNA was found to significantly increase stability in vitro compared to the wild-type sequence. CONCLUSION: Our findings show an association between RA and a previously unreported polymorphism in the hGR gene. This polymorphism increased stability of hGRbeta mRNA, which could contribute to an altered glucocorticoid sensitivity since the hGRbeta is thought to function as an inhibitor of hGRalpha activity.

Uptake and killing of Listeria monocytogenes by normal human peripheral blood granulocytes and monocytes as measured by flow cytometry and cell sorting.

Cellular components of innate immunity (NK cells, monocytes and granulocytes) play an important role in early resistance to Listeria monocytogenes in the mouse model. Minimally invasive methods of measuring the bacteriocidal capacity of these cells may be useful as a biomarker of susceptibility in humans. A technique was developed whereby the uptake and survival of L. monocytogenes could be measured in human granulocytes and monocytes using small volumes of peripheral blood. This method used flow cytometry to detect the presence of PKH-2-labeled bacteria within these cells. Survival of bacteria was determined by sorting of infected cells based on a combination of fluorescence and light scattering properties. Considerable variation in bacterial recovery was seen between normal volunteers. There was consistently greater survival of a fully virulent strain of L. monocytogenes within monocytes and granulocytes compared with an isogenic strain lacking the hemolysin, listeriolysin O, when measured at baseline. There was no evidence of longer-term bacterial survival or growth at 2 or 24 h. This technique may be useful for assessment of both host resistance and pathogen virulence.

Neuroendocrine regulation of autoimmune/inflammatory disease.

Interactions between the immune and nervous systems play an important role in modulating host susceptibility and resistance to inflammatory disease. Neuroendocrine regulation of inflammatory and immune responses and disease occurs at multiple levels: systemically, through the anti-inflammatory action of glucocorticoids released via hypothalamic-pituitary-adrenal axis stimulation; regionally, through production of glucocorticoids within and sympathetic innervation of immune organs such as the thymus; locally, at sites of inflammation. Estrogens also play an important role in immune modulation, and contribute to the approximately 2- to 10-fold higher incidence of autoimmune/inflammatory diseases seen in females of all mammalian species. During inflammation, cytokines from the periphery activate the central nervous system through multiple routes. This results in stimulation of the hypothalamic-pituitary-adrenal axis which, in turn through the immunosuppressive effects of the glucocorticoids, generally inhibits inflammation. Recent studies indicate that physiological levels of glucocorticoids are immunomodulatory rather than solely immunosuppressive, causing a shift in patterns of cytokine production from a TH1- to a TH2-type pattern. Interruptions of this loop at any level and through multiple mechanisms, whether genetic, or through surgical or pharmacological interventions, can render an inflammatory resistant host susceptible to inflammatory disease. Over-activation of this axis, as occurs during stress, can also affect severity of infectious disease through the immunosuppressive effects of the glucocorticoids. These interactions have been clearly demonstrated in many animal models, across species, strains and diseases, and are also relevant to human inflammatory, autoimmune and allergic illnesses, including rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, allergic asthma and atopic skin disease. While many genes and environmental factors contribute to susceptibility and resistance to autoimmune/inflammatory diseases, a full understanding of the molecular effects on immune responses of combinations of neuropeptides, neurohormones and neurotransmitters at all levels has opened up new therapeutic approaches and are essential for the design of future therapies based on such principles.

Neuroendocrine responses regulating susceptibility and resistance to autoimmune/inflammatory disease in inbred rat strains.

Rodent animal models of inflammatory and autoimmune disease have been important tools in the study of the interaction between neuroendocrine physiology and the immune responses. The rat has been particularly useful in part because, in contrast to other species, most rat models of autoimmune/inflammatory disease are induced rather than spontaneous. This allows for systematic and controlled manipulations of the neuroendocrine system in relation to exposure to the antigen or proinflammatory trigger. The most frequently used immune challenges include lipopolysaccharide-induced septic shock, carrageenan-induced local inflammation and adjuvant or bacterial cell wall-induced arthritis. By analyzing the responses to these challenges in different strains of rats and mice it has been possible to define the relationships between the neuroendocrine and immune systems and to identify some mechanisms through which these connections confer susceptibility and resistance to autoimmune and inflammatory diseases. The present review will discuss data obtained from rodent physiology, indicating that an important component in the susceptibility or resistance to development of these diseases is due to dysfunctional regulation of the immune response by the neuroendocrine hypothalamic-pituitary-adrenal axis. In particular, the importance of neurons of the paraventricular hypothalamic nucleus in determining susceptibility or resistance to autoimmune and inflammatory disease will be discussed.

Anti-inflammatory cytokines: expression and action in the brain.

Transforming growth factor-beta(1) (TGF-beta(1)) and interleukin (IL)-10 gene expression is equivocal in normal brain and upregulated in over a dozen central and peripheral diseases/disorders. The patterns of specific expression of cytokines differ in these diseases. Published data indicate that these cytokines are produced by and act on both neurons and glial cells. Although their actions are commonly viewed as 'anti-inflammatory', they protect neurons and downregulate the responses of glial cells to diseases/disorders in the absence of inflammation. Their actions counterbalance the actions of elevated IL-1 and/or tumor necrosis factor-alpha to maintain homeostasis. Their therapeutic potential will be realized by improving our understanding of their place in neural cytokine networks.

Emotional selection in memes: the case of urban legends.

This article explores how much memes like urban legends succeed on the basis of informational selection (i.e., truth or a moral lesson) and emotional selection (i.e., the ability to evoke emotions like anger, fear, or disgust). The article focuses on disgust because its elicitors have been precisely described. In Study 1, with controls for informational factors like truth, people were more willing to pass along stories that elicited stronger disgust. Study 2 randomly sampled legends and created versions that varied in disgust; people preferred to pass along versions that produced the highest level of disgust. Study 3 coded legends for specific story motifs that produce disgust (e.g., ingestion of a contaminated substance) and found that legends that contained more disgust motifs were distributed more widely on urban legend Web sites. The conclusion discusses implications of emotional selection for the social marketplace of ideas.

Effects of cross fostering on open-field behavior, acoustic startle, lipopolysaccharide-induced corticosterone release, and body weight in Lewis and Fischer rats.

Lewis (LEW/N) and Fischer (F344/N) rats differ on a myriad of behavioral and physiological endpoints, some of which have been reported to be affected by maternal experience in outbred rats and other strains. To assess whether epigenetic factors contribute to the differential behavioral responses to stress and pro-inflammatory challenges in these strains, the effects of cross fostering on open-field, acoustic startle, and glucocorticoid reactivity to lipopolysaccharide (LPS) were examined in the present experiment. In the open-field test, although in-fostered female LEW/N and F344/N strains did not differ, female LEW/N rats displayed significantly greater activity than female F344/N rats in the cross-fostered condition. Differences between males of the two strains were increased by cross fostering, with the LEW/N strain displaying greater total activity. In acoustic startle, there was little strain difference between in-fostered or cross-fostered female rats. On the other hand, in-fostered male LEW/N rats had a significantly greater startle response than in-fostered male F344/N rats, an effect that was dramatically reduced by cross fostering. In-fostered female LEW/N rats displayed a blunted corticosterone response relative to in-fostered female F344/N rats, an effect that was reduced by cross fostering. Conversely, although there was no strain difference between male in-fostered rats, cross-fostered male F344/N rats displayed a significantly greater corticosterone response to LPS than cross-fostered male LEW/N rats. Finally, body weight differences between in-fostered LEW/N and F344/N rats were reduced by cross fostering. Together, these data illustrate that maternal factors play a role in the behavioral and physiological responses to stress between the two strains.

Maternal estrogen receptor-beta expression during mouse gestation.

PROBLEM: Although estrogen receptor (ER)-alpha has been well characterized, the recently identified novel ER-beta has not. In some tissues, there is overlap of the ERs, which allows for rescue in cases of deficiency; in other tissues, the ERs appear to have opposite effects. The objective of this study was to evaluate the expression of ER-beta during pregnancy. METHOD OF STUDY: Pregnant mouse uteri (embryonic days 6-14, 16, 18) were studied. ER-alpha and ER-beta oligonucleotide probes were end-labeled and in situ hybridization histochemistry was performed. RESULTS: ER-beta was strongly expressed in maternal ovaries; there was no other evidence of strong expression during gestation. ER-alpha was expressed in the uterus throughout gestation, with decreasing intensity as gestation progressed, and in maternal ovarian tissue. CONCLUSIONS: Differential expression of the two ERs was apparent during pregnancy, with ER-alpha playing a dominant role. This may have implications for selective drug treatment targeting estrogen receptors.

Multimodality management in severe pediatric spleen trauma.

BACKGROUND: Trauma is the leading cause of death in children. In abdominal lesions the spleen is the most commonly involved organ. During the last two decades much effort has focused on spleen tissue conservation. OBJECTIVES: To analyze the rationale of a multimodality management policy that includes autotransfusion and mesh wrapping. METHODS: Data gathered over 14 years illustrate the introduction of new techniques and their impact on cases of severe spleen rupture. RESULTS: A total of 122 children were treated during the 14 year period, 1985-98. In 16 children an absorbable mesh wrapping, alone or in combination with other techniques, was used to obtain hemostatis and save spleen tissue. CONCLUSIONS: Mesh wrapping, partial splenectomy and autotransfusion can be used, alone or in combination, to preserve severely injured spleens. According to our records, all children survived with a functional spleen. There were no cases of rebleeding. In only one case of prolonged postoperative fever could the cause be traced to an infected spleen hematoma that was drained transcutaneously. Autotransfusion is performed simply and without the use of a "cell saver." Its use can be crucial in small or field hospitals or in a situation of mass casualty.

Exclusion of angiotensin I-converting enzyme as a candidate gene involved in exudative inflammatory resistance in F344/N rats.

BACKGROUND: Inbred LEW/N and F344/N rats respectively, are susceptible and relatively resistant to a broad range of inflammatory/autoimmune diseases. We recently identified a quantitative trait locus (QTL) on chromosome 10 that protects the F344/N rat from carrageenan-induced exudation in a dominant fashion. Angiotensin I-converting enzyme (ACE) is one of the candidate genes located in this QTL region that plays an important role in inflammation. MATERIALS AND METHODS: RNA was extracted from both LEW/N and F344/N rat strains and used to produce full length cDNA by reverse transcription polymerase chain reaction (RT-PCR). Both strands of the PCR products were entirely sequenced to determine nucleotide differences between strains. ACE activity was measured using the synthetic substrate 3H-hippuryl-glycylglycine. ACE protein levels were determined by Western blot using a specific ACE antibody. ACE kinetic and inhibition studies were performed using specific substrates (Hip-His-Leu and Acetyl-Seryl-Aspartyl-Acetyl-Lysyl-Proline) and inhibitors (lisinopril, captopril and quinaprilat) for each C- and N-terminal active site. Finally, the dose-effects of lisinopril treatment on carrageenen-induced exudate volume and ACE activity was studied. RESULTS: In this study, we report for the first time a missense mutation in the coding region of ACE cDNA at 5' 1021 from C to T, resulting in a Leu-341 to Phe substitution, close to the N-domain active site in the F344/N rats. Full characterization of soluble and tissue ACE in both LEW/N and F344/N rat strains showed that soluble ACE levels in serum and exudate were 1.5 fold higher in the F344/N rats than those in LEW/N rats. In addition, the soluble ACE level was inversely correlated with the exudate volume. However, the specific ACE activity and its catalytic properties were identical in both strains. Furthermore, the chronic inhibition of serum and exudate ACE levels by lisinopril treatment did not affect the exudate volume in F344/N rats, indicating that several factors besides ACE were involved in the control of carrageenan-induced exudation. CONCLUSIONS: This report describes a complete molecular, biochemical, enzymatic and pharmacologic study of a missense mutation in the ACE cDNA in F344/N rats, that taken together, excludes ACE as a candidate gene involved with resistance to carrageenan-induced exudation in F344/N rats.