Hyperbaric hyperoxia alters innate immune functional properties during NASA Extreme Environment Mission Operation (NEEMO).

BACKGROUND: Spaceflight is associated with immune dysregulation which is considered as risk factor for the performance of exploration-class missions. Among the consequences of confinement and other environmental factors of living in hostile environments, the role of different oxygen concentrations is of importance as either low (e.g. as considered for lunar or Martian habitats) or high (e.g. during extravehicular activities) can trigger immune dysfunction. The aim of this study was to investigate the impact of increased oxygen availability--generated through hyperbaricity--on innate immune functions in the course of a 14 days NEEMO mission. METHODS: 6 male subjects were included into a 14 days undersea deployment at the Aquarius station (Key Largo, FL, USA). The underwater habitat is located at an operating depth of 47 ft. The 2.5 times higher atmospheric pressure in the habitat leads to hyperoxia. The collection of biological samples occurred 6 days before (L-6), at day 7 (MD7) and 11/13 (MD11/13) during the mission, and 90 days thereafter (R). Blood analyses included differential blood cell count, ex vivo innate immune activation status and inhibitory competences of granulocytes. RESULTS: The absolute leukocyte count showed an increase during deployment as well as the granulocyte and monocyte count. Lymphocyte count was decreased on MD7. The assessments of native adhesion molecules on granulocytes (CD11b, CD62L) indicated a highly significant cellular activation (L-6 vs. MD7/MD13) during mission. In contrast, granulocytes were more sensitive towards anti-inflammatory stimuli (adenosine) on MD13. CONCLUSION: Living in the NEEMO habitat for 14 days induced significant immune alterations as seen by an activation of adhesion molecules and vice versa higher sensitivity towards inhibition. This investigation under hyperbaric hyperoxia is important especially for Astronauts' immune competence during extravehicular activities when exposed to similar conditions.

Multiple latent viruses reactivate in astronauts during Space Shuttle missions.

Latent virus reactivation and diurnal salivary cortisol and dehydroepiandrosterone were measured prospectively in 17 astronauts (16 male and 1 female) before, during, and after short-duration (12-16 days) Space Shuttle missions. Blood, urine, and saliva samples were collected during each of these phases. Antiviral antibodies and viral load (DNA) were measured for Epstein-Barr virus (EBV), varicella-zoster virus (VZV), and cytomegalovirus (CMV). Three astronauts did not shed any virus in any of their samples collected before, during, or after flight. EBV was shed in the saliva in all of the remaining 14 astronauts during all 3 phases of flight. Seven of the 14 EBV-shedding subjects also shed VZV during and after the flight in their saliva samples, and 8 of 14 EBV-shedders also shed CMV in their urine samples before, during, and after flight. In 6 of 14 crewmembers, all 3 target viruses were shed during one or more flight phases. Both EBV and VZV DNA copies were elevated during the flight phase relative to preflight or post-flight levels. EBV DNA in peripheral blood was increased preflight relative to post-flight. Eighteen healthy controls were also included in the study. Approximately 2-5% of controls shed EBV while none shed VZV or CMV. Salivary cortisol measured preflight and during flight were elevated relative to post-flight. In contrast DHEA decreased during the flight phase relative to both preflight and post-flight. As a consequence, the molar ratio of the area under the diurnal curve of cortisol to DHEA with respect to ground (AUCg) increased significantly during flight. This ratio was unrelated to viral shedding. In summary, three herpes viruses can reactivate individually or in combination during spaceflight.

Reactivation of latent viruses is associated with increased plasma cytokines in astronauts.

Success of long duration space missions will depend upon robust immunity. Decreased immunity has been observed in astronauts during short duration missions, as evident by the reactivation of latent herpes viruses. Seventeen astronauts were studied for reactivation and shedding of latent herpes viruses before, during, and after 9-14 days of 8 spaceflights. Blood, urine, and saliva samples were collected 10 days before the flight (L-10), during the flight (saliva only), 2-3h after landing (R+0), 3 days after landing (R+3), and 120 days after landing (R+120). Values at R+120 were used as baseline levels. No shedding of viruses occurred before flight, but 9 of the 17 (designated "virus shedders") shed at least one or more viruses during and after flight. The remaining 8 astronauts did not shed any of the 3 target viruses (non-virus shedders). Virus-shedders showed elevations in 10 plasma cytokines (IL-1α, IL-6, IL-8, IFNγ, IL-4, IL-10, IL-12, IL-13, eotaxin, and IP-10) at R+0 over baseline values. Only IL-4 and IP-10 were elevated in plasma of non-virus shedders. In virus shedders, plasma IL-4 (a Th2 cytokine) was elevated 21-fold at R+0, whereas IFNγ (a Th1 cytokine) was elevated only 2-fold indicating a Th2 shift. The inflammatory cytokine IL-6 was elevated 33-fold at R+0. In non-shedding astronauts at R+0, only IL-4 and IP-10 levels were elevated over baseline values. Elevated cytokines began returning to normal by R+3, and by R+120 all except IL-4 had returned to baseline values. These data show an association between elevated plasma cytokines and increased viral reactivation in astronauts.

Dopamine agonist therapy in early Parkinson's disease.

BACKGROUND: Dopamine agonists are being used increasingly as first line treatment for Parkinson's disease, but there remains uncertainty about their clinical and cost-effectiveness relative to levodopa. OBJECTIVES: This meta-analysis aims to quantify more reliably the benefits and risks of dopamine agonists compared to placebo or levodopa in early Parkinson's disease. SEARCH STRATEGY: We searched CENTRAL (The Cochrane Library), MEDLINE, EMBASE, PubMed, LILACS and Web of Science, plus major journals in the field, abstract books, conference proceedings and reference lists of retrieved publications. SELECTION CRITERIA: Randomised trials comparing an orally administered dopamine agonist (with or without levodopa) versus placebo or levodopa or both placebo and levodopa in participants with early Parkinson's disease. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data on clinician-rated disability, motor complications, other side-effects, treatment concordance, levodopa dose and mortality. MAIN RESULTS: Twenty-nine eligible trials, involving 5247 participants, were identified. Participants randomised to a dopamine agonist were less likely to develop dyskinesia (odds ratio (OR) 0.51, 95% confidence interval (CI) 0.43 to 0.59; P < 0.00001), dystonia (OR 0.64, 95% CI 0.51 to 0.81; P = 0.0002) and motor fluctuations (OR 0.75, 95% CI 0.63 to 0.90; P = 0.002) than levodopa-treated participants. However, various 'non-motor' side-effects, including oedema (OR 3.68, 95% CI 2.62 to 5.18; P < 0.00001), somnolence (OR 1.49, 95% CI 1.12 to 2.00; P = 0.007), constipation (OR 1.59, 95% CI 1.11 to 2.28; P = 0.01), dizziness (OR 1.45, 95% CI 1.09 to 1.92; P = 0.01), hallucinations (OR 1.69, 95% CI 1.13 to 2.52; P = 0.01) and nausea (OR 1.32, 95% CI 1.05 to 1.66; P = 0.02) were all increased in agonist-treated participants (compared with levodopa-treated participants). Agonist-treated participants were also significantly more likely to discontinue treatment due to adverse events (OR 2.49, 95% CI 2.08 to 2.98; P < 0.00001). Finally symptomatic control of Parkinson's disease was better with levodopa than with agonists, but data were reported too inconsistently and incompletely to meta-analyse. AUTHORS' CONCLUSIONS: This meta-analysis confirms that motor complications are reduced with dopamine agonists compared to levodopa, but also establishes that other important side-effects are increased and symptom control is poorer with agonists. Larger, long-term comparative trials assessing patient-rated quality of life are needed to assess more reliably the balance of benefits and risks of dopamine agonists compared to levodopa.

Low molecular weight GTP-binding proteins are altered in platelet hyperaggregation in IDDM.

We examined the hypothesis that hyperaggregating platelets from patients with insulin dependent diabetes mellitus (IDDM) have an alteration in location and function of the guanine nucleotide (GTP)-binding proteins. Platelets from 10 IDDM and 12 age-matched healthy control subjects were collected and washed. Thrombin-induced platelet aggregation (0.025 and 0.05 units for 60 seconds) was increased in IDDM (8.3 +/- 1.8% vs 22.3 +/- 4.4%, P < .05 and 49.9 +/- 7.3% vs 70.9 +/- 7.0%, P < .05). Four small molecular weight GTP-binding proteins were identified by binding of [32P]-GTP on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the cytosol and membranes of these platelets. Each showed specificity for binding [32P]-GTP by competitive inhibition with unlabeled GTP. The total of the 27/28 kDa proteins was decreased in the membrane fraction (414 +/- 30 vs 252 +/- 40 dpm micrograms-1 protein x min, P < .05) and increased in the cytosolic fraction (62 +/- 8 vs 129 +/- 21 dpm unit-1 LDH x min, P < .05) in IDDM. The 21 kDa protein (60.3 +/- 3.5 vs 45.4 +/- 2.9 dpm micrograms-1 protein x min, P < .05) was decreased in platelet membrane in persons with IDDM. In conclusion, increased platelet aggregation in IDDM is accompanied by an altered cellular distribution of a 27/28 kDa GTP-binding protein. These data suggest that the low molecular weight GTP-binding proteins of the 27/28 kDa range may play an important regulatory role in the hyperaggregatory platelets in diabetes.

Leukocyte subsets and neutrophil function after short-term spaceflight.

Changes in leukocyte subpopulations and function after spaceflight have been observed but the mechanisms underlying these changes are not well defined. This study investigated the effects of short-term spaceflight (8-15 days) on circulating leukocyte subsets, stress hormones, immunoglobulin levels, and neutrophil function. At landing, a 1.5-fold increase in neutrophils was observed compared with preflight values; lymphocytes were slightly decreased, whereas the results were variable for monocytes. No significant changes were observed in plasma levels of immunoglobulins, cortisol, or adrenocorticotropic hormone. In contrast, urinary epinephrine, norepinephrine, and cortisol were significantly elevated at landing. Band neutrophils were observed in 9 of 16 astronauts. Neutrophil chemotactic assays showed a 10-fold decrease in the optimal dose response after landing. Neutrophil adhesion to endothelial cells was increased both before and after spaceflight. At landing, the expression of MAC-1 was significantly decreased while L-selectin was significantly increased. These functional alterations may be of clinical significance on long-duration space missions.

Monoamine oxidase B inhibitors for early Parkinson's disease.

BACKGROUND: It has been postulated that monoamine oxidase B (MAO-B) inhibitors alter disease progression in Parkinson's disease (PD). Clinical trials have produced conflicting results. OBJECTIVES: To assess the evidence from randomized controlled trials for the effectiveness and safety of long-term use of MAO-B inhibitors in early PD. SEARCH STRATEGY: We searched the following electronic databases: Cochrane Central Register of Controlled trials (CENTRAL) (The Cochrane Library Issue 2, 2004), MEDLINE (last searched 18th August 2004) and EMBASE (last searched 18th August 2004). We also handsearched neurology and movement disorders conference proceedings, checked reference lists of relevant studies and contacted other researchers. SELECTION CRITERIA: We sought to include all unconfounded randomized controlled trials that compared a MAO-B inhibitor with control, in the presence or absence of levodopa or dopamine agonists, in patients with early PD and where treatment and follow up lasted at least one year. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed the methodological quality, and extracted the data. A small amount of additional data was provided by the original authors. Random-effects models were used to analyse results, where appropriate. MAIN RESULTS: Ten trials were included (a total of 2422 patients), nine using selegiline, one using lazabemide. The methodological quality was reasonable although concealment of allocation was definitely adequate in only four trials. The mean follow up was for 5.8 years. MAO-B inhibitors were not associated with a significant increase in deaths (odds ratio (OR) 1.15; 95% confidence interval (CI) 0.92 to 1.44). They provided small benefits over control in impairment (weighted mean difference (WMD) for change in motor UPDRS score was 3.81 points less with MAO-B inhibitors; 95% CI 2.27 to 5.36) and disability (WMD for change in UPDRS ADL score was 1.50 less; 95% CI 0.48 to 2.53) at one year which, although statistically significant, were not clinically significant. There was a marked levodopa-sparing effect with MAO-B inhibitors which was associated with a significant reduction in motor fluctuations (OR 0.75; 95% CI 0.59 to 0.94) but not dyskinesia (OR 0.97; 95% CI 0.76 to 1.25). The reduction in motor fluctuations was, however, not robust in sensitivity analyses. Although adverse events were generally mild and infrequent, withdrawals due to side-effects were higher (OR 2.36; 95% CI 1.32 to 4.20) with MAO-B inhibitors. AUTHORS' CONCLUSIONS: MAO-B inhibitors do not appear to delay disease progression but may have a beneficial effect on motor fluctuations. There was no statistically significant effect on deaths although the confidence interval does not exclude a small increase with MAO-B inhibitors. At present we do not feel these drugs can be recommended for routine use in the treatment of early Parkinson's disease but further randomized controlled trials should be carried out to clarify, in particular, their effect on deaths and motor complications.

Accuracy of four clinical diagnostic criteria for the diagnosis of neurodegenerative dementias.

OBJECTIVE: To evaluate the inter-rater reliability and validity of clinical diagnostic criteria for neurodegenerative dementias. BACKGROUND: Inter-rater accuracy of the diagnosis of AD has been explored, but there are few accuracy studies for progressive supranuclear palsy (PSP) and frontotemporal lobe dementia (FTD). Furthermore, there have been no simultaneous accuracy studies in a mixed sample of patients with cortical and subcortical neurodegenerative processes. METHODS: Four experienced clinicians reviewed first-visit clinical data abstracted from the records of 40 pathologically diagnosed demented subjects. They were asked to apply the NINCDS-ADRDA criteria for AD, the NINDS-SPSP clinical criteria for PSP, the Lund and Manchester criteria for FTD, and the Consensus Guidelines for the Clinical Diagnosis of Dementia with Lewy Bodies (DLB). RESULTS: The generalized K for AD was 0.73, for PSP 0.82, for FTD 0.75, and for DLB 0.37. The K pool test showed a statistically significant difference between DLB and the other disease processes, and no differences were observed among AD, FTD, and PSP. The mean sensitivity for AD was 95%, for PSP 75%, for FTD 97%, and for DLB 34%. The mean specificity for AD was 79%, for PSP 98.5%, for FTD 97%, and for DLB 94%. CONCLUSIONS: We found improved inter-rater reliability for the diagnosis of AD among clinicians compared with earlier studies. Similarly, there was a near-perfect and substantial inter-rater agreement for the diagnosis of PSP and FTD. The sensitivity for the diagnosis of AD was high, although clinicians overdiagnosed this condition. However, there was a reasonable accuracy for the diagnosis of PSP and FTD. Heterogeneity of the clinical presentation of DLB significantly affected inter-rater agreement and accuracy. The use of multiple diagnostic criteria for cortical and subcortical dementia increases the level of clinical diagnostic accuracy.

Routine detection of Epstein-Barr virus specific T-cells in the peripheral blood by flow cytometry.

The ability to detect cytomegalovirus-specific T-cells (CD4(+)) in the peripheral blood by flow cytometry has been recently described by Picker et al. In this method, cells are incubated with viral antigen and responding (cytokine producing) T-cells are then identified by flow cytometry. To date, this technique has not been reliably used to detect Epstein-Barr virus (EBV)-specific T-cells primarily due to the superantigen/mitogenic properties of the virus which non-specifically activate T-cells. By modifying culture conditions under which the antigens are presented, we have overcome this limitation and developed an assay to detect and quantitate EBV-specific T-cells. The detection of cytokine producing T-cells by flow cytometry requires an extremely strong signal (such as culture in the presence of PMA and ionomycin). Our data indicate that in modified culture conditions (early removal of viral antigen) the non-specific activation of T-cells by EBV is reduced, but antigen presentation will continue uninhibited. Using this method, EBV-specific T-cells may be legitimately detected using flow cytometry. No reduction in the numbers of antigen-specific T-cells was observed by the early removal of target antigen when verified using cytomegalovirus antigen (a virus with no non-specific T-cell activation properties). In EBV-seropositive individuals, the phenotype of the EBV-specific cytokine producing T-cells was evaluated using four-color flow cytometry and found to be CD45(+), CD3(+), CD4(+), CD45RA(-), CD69(+), CD25(-). This phenotype indicates the stimulation of circulating previously unactivated memory T-cells. No cytokine production was observed in CD4(+) T-cells from EBV-seronegative individuals, confirming the specificity of this assay. In addition, the use of four color cytometry (CD45, CD3, CD69, IFNgamma/IL-2) allows the total quantitative assessment of EBV-specific T-cells while monitoring the interference of EBV non-specific mitogenic activity. This method may have significant utility for the monitoring of the immune response to latent virus infection/reactivation.

Selective labelling of 5-HT7 receptor recognition sites in rat brain using [3H]5-carboxamidotryptamine.

The aim of the present study was to establish a radioligand binding assay to selectively label the native 5-HT7 receptor expressed in rat brain. In rat whole brain (minus cerebellum and striatum) homogenate, (+/-)-pindolol (10 microM)-insensitive [3H]5-CT ([3H]5-carboxamidotryptamine; 0.5 nM) specific binding (defined by 5-HT, 10 microM) displayed a pharmacological profile similar to the recombinant 5-HT7 receptor, although the Hill coefficients for competition curves generated by methiothepin, ritanserin, sumatriptan, clozapine and pimozide were significantly less than unity. In homogenates of rat hypothalamus, (+/-)-pindolol (10 microM)-insensitive [3H]5-CT recognition sites also resembled, pharmacologically, the 5-HT7 receptor, although pimozide still generated Hill coefficients significantly less than unity. Subsequent studies were performed in the additional presence of WAY100635 (100 nM) to prevent [3H]5-CT binding to residual, possibly, 5-HT1A sites. Competition for this [3H]5-CT binding indicated the labelling in whole rat brain homogenate of a homogenous population of sites with the pharmacological profile of the 5-HT7 receptor. Saturation studies also indicated that (+/-)-pindolol (10 microM)/WAY 100635 (100 nM)-insensitive [3H]5-CT binding to homogenates of whole rat brain was saturable and to an apparently homogenous population of sites which were labelled with nanomolar affinity (Bmax=33.2+/-0.7 fmol mg(-1) protein, pKd=8.78+/-0.05, mean+/-S.E.M., n=3). The development of this 5-HT7 receptor binding assay will aid investigation of the rat native 5-HT7 receptor.

Spreadsheet macro for setting up PCR assay tubes.

This article describes a Microsoft Excel macro designed to calculate PCR master mix amounts based on variations in the DNA template amounts added to each tube, the total number of PCR assay tubes being set up or both. This macro uses a dynamic dialog box to quickly calculate and display the new component volumes after changes in one or both of the variables. The PCR assay mix protocol can then be printed in a format suitable for record keeping. This macro was designed for use with the Windows version of Excel but will also run on Macintosh computers.

Ability of 5-HT4 receptor ligands to modulate rat striatal dopamine release in vitro and in vivo.

1. The ability of 5-HT4 (5-hydroxytryptamine4) receptor ligands to modify dopamine release from rat striatal slices in vitro and in the striatum of freely moving rats was assessed by the microdialysis technique. 2. The release of dopamine from slices of rat striatum continually perfused with Krebs buffer was enhanced by 5-HT4 receptor agonists; 5-HT (10 microM), 5-methoxytryptamine (5-MeOT; 10 microM), renzapride (10 microM) and (S)-zacopride (10 microM) maximally increased dopamine release by 133 +/- 5, 214 +/- 25, 232 +/- 29 and 264 +/- 69%, respectively (mean +/- s.e.mean, n = 3-8). The drug-induced responses were maximal within the first 2 min of drug application, and subsequently declined. The non-selective 5-HT3/5-HT4 receptor antagonist, SDZ205-557 (10 microM), failed to modify basal dopamine release from striatal slices but completely antagonized the (S)-zacopride (10 microM)-induced increase in dopamine release. 3. To allow faster drug application, the modulation of dopamine release from rat striatal slices in a static release preparation was also investigated. The 5-HT4 receptor agonist, renzapride (10 microM) also enhanced dopamine release in this preparation (maximal increase = 214 +/- 35%, mean +/- s.e.mean, n = 14), whilst a lower concentration of renzapride (3 microM) was less effective. The renzapride-induced response was maximal within the first 2 min of drug application, before declining. In this preparation, the stimulation of dopamine release by renzapride (10 microM), was completely antagonized by the selective 5-HT4 receptor antagonist, GR113808 (100 nM). In addition, both the Na+ channel blocker, tetrodotoxin (100 nM) and the non-selective protein kinase A inhibitor, H7 (100 nM) completely prevented the stimulation of dopamine release induced by renzapride (10 microM). 4. In vivo microdialysis studies demonstrated that the 5-HT4 receptor agonists, 5-MeOT (10 microM), renzapride (100 microM) and (S)-zacopride (100 microM) maximally elevated extracellular levels of dopamine in the striatum by 220 +/- 20, 161 +/- 10 and 189 +/- 53%, respectively (mean +/- s.e.mean, n = 5-9). A lower concentration of renzapride (10 microM) was less effective. The elevation of extracellular striatal dopamine levels induced by either renzapride (100 microM) or (S)-zacopride (100 microM) were completely antagonized by the non-selective 5-HT4 receptor antagonist, SDZ205-557 (100 microM). In addition, the elevation of extracellular levels of dopamine induced by either 5-MeOT (10 microM) or renzapride (100 microM) was completely prevented by the selective 5-HT4 receptor antagonist, GR113808 (1 microM) and the renzapride (100 microM)-induced response was also completely prevented by the non-selective protein kinase A inhibitor, H7 (1 microM). In this in vivo preparation, both GR113808 (1 microM) and H7 (1 microM), when perfused alone, reduced extracellular levels of dopamine. 5. In conclusion, the present study provides evidence that the 5-HT4 receptor facilitates rat striatal dopamine release in vitro and in vivo.

Detection and quantification of Epstein-Barr virus EBER1 in EBV-infected cells by fluorescent in situ hybridization and flow cytometry.

A rapid and highly sensitive fluorescent in situ hybridization (FISH) assay was developed to detect Epstein Barr virus (EBV)-infected cells in peripheral blood. Multiple fluorescein-labeled antisense oligonucleotide probes were designed to hybridize to the EBER1 transcript, which is highly expressed in latently infected cells. After a rapid (30 min) hybridization, the cells were analyzed by flow cytometry. EBER1 was detected in several positive control cell lines that have variable numbers of EBV genome copies. No EBER1 was detected in two known EBV-negative cell lines. Northern blot analyses confirmed the presence and quantity of EBER1 transcripts in each cell line. This method was used to quantify the number of EBV-infected cells in peripheral blood from a patient with chronic mononucleosis. These results indicate that EBV-infected cells can be detected at the single cell level, and that this assay can be used to quantify the number of EBV-infected cells in clinical samples.

Incidence of Epstein-Barr virus in astronaut saliva during spaceflight.

BACKGROUND: Astronauts experience psychological and physical stresses that may result in reactivation of latent viruses during space-flight, potentially increasing the risk of disease among crewmembers. HYPOTHESIS: The shedding of Epstein-Barr virus (EBV) in the saliva of astronauts will increase during spaceflight. METHODS: A total of 534 saliva specimens were collected from 11 EBV-seropositive astronauts before, during, and after four space shuttle missions. The presence of EBV DNA in saliva, assessed by polymerase chain reaction (PCR), was used to determine shedding patterns before, during, and after space-flight. RESULTS: EBV DNA was detected more frequently before flight than during (p < 0.001) or after (p < 0.01) flight. No significant difference between the inflight and postflight periods was detected in the frequency of occurrence of EBV DNA. CONCLUSIONS: The increased frequency of shedding of EBV before flight suggests that stress levels may be greater before launch than during or after spaceflight.

Immune responses and latent herpesvirus reactivation in spaceflight.

BACKGROUND: Increased frequency and severity of herpesvirus infections are common in individuals with impaired cellular immunity, a phenomenon observed in both the elderly and astronauts alike. This study investigated immune responses and latent herpesvirus reactivation during a 9-d spaceflight. In addition, adrenocortical and immune responses of an elderly astronaut (payload specialist-2, PS2; age 77) who flew on this mission were compared with that of younger crewmembers. HYPOTHESIS: Spaceflight and associated stresses will decrease cellular immunity and reactivate latent herpesviruses. METHODS: Blood and urine samples, collected from the seven crewmembers who flew on the Space Shuttle Discovery (STS-95), were analyzed for levels of neuroendocrine hormones, leukocyte and lymphocyte subsets, and evidence of herpes-virus reactivation. RESULTS: Prior to flight, increased antibody titers to latent Epstein-Barr virus were found. During flight, acute changes in dehydroepiandrosterone sulfate (DHEAS) and cortisol resulted in a pronounced decrease in the DHEAS/cortisol ratio by the end of the mission for PS2 and a younger crewmember. Shedding of cytomegalovirus (CMV) in urine and increased CMV antibody titers also occurred inflight. At landing, the percent increases in adrenocorticotropic hormone and cortisol were greatest for PS2 as compared with the other six crewmembers. A significant neutrophilia also was observed in all crewmembers. Notably, PS2 had large increases in monocytes and natural killer cells at landing while other crewmembers showed little change or a decrease. CONCLUSIONS: These findings indicate that spaceflight and associated stresses reactivate latent herpesviruses and suggest that acute changes in neuroendocrine hormones mediate these changes in part by downregulating cellular immunity. Moreover, the similarities between aging and spaceflight suggest that the study of the immune system in elderly subjects may be useful as a predictive model for astronauts enduring long-term spaceflights.

Environmental hazards and stress: evidence from the Texas City Stress and Health Study.

BACKGROUND: Substantial research has suggested that exposure to environmental health hazards, such as polluting industrial activity, has deleterious effects on psychological and physiological well-being. However, one gap in the existing literature is comparative analysis of objective and subjective exposure's relative association with various measurable outcomes of exposure. METHODS: These relationships were explored within a community sample of 2604 respondents living near a large petrochemical complex in Texas City, Texas, USA. Objective exposure was investigated using distance of residence from a cluster of petrochemical plants and subjective exposure using residents' concern about potential health effects from those plants. Regression models were then used to examine how each type of exposure predicts perceived stress, physiological markers of stress and perceived health. RESULTS: Results suggest that objective exposure was associated primarily with markers of physiological stress (interleukin-6 and viral reactivation), and subjective exposure (concern about petrochemical health risk) was associated with variables assessing perceived health. CONCLUSIONS: From the analysis, it can be inferred that, in the context of an environmental hazard of this type, subjective exposure may be at least as important a predictor of poor health outcomes as objective exposure.

Epstein-Barr virus shedding by astronauts during space flight.

Patterns of Epstein-Barr virus (EBV) reactivation in 32 astronauts and 18 healthy age-matched control subjects were characterized by quantifying EBV shedding. Saliva samples were collected from astronauts before, during, and after 10 space shuttle missions of 5-14 days duration. At one time point or another, EBV was detected in saliva from each of the astronauts. Of 1398 saliva specimens from 32 astronauts, polymerase chain reaction analysis showed that 314 (23%) were positive for EBV DNA. Examination by flight phase showed that 29% of the saliva specimens collected from 28 astronauts before flight were positive for EBV DNA, as were 16% of those collected from 25 astronauts during flight and 16% of those collected after flight from 23 astronauts. The mean number of EBV copies from samples taken during the flights was 417 per mL, significantly greater (p<.05) than the number of viral copies from the preflight (40) and postflight (44) phases. In contrast, the control subjects shed EBV DNA with a frequency of 3.7% and mean number of EBV copies of 40 per mL of saliva. Ten days before flight and on landing day, titers of antibody to EBV viral capsid antigen were significantly (p<.05) greater than baseline levels. On landing day, urinary levels of cortisol and catecholamines were greater than their preflight values. In a limited study (n=5), plasma levels of substance P and other neuropeptides were also greater on landing day. Increases in the number of viral copies and in the amount of EBV-specific antibody were consistent with EBV reactivation before, during, and after space flight.

Assessing the scientific strength of Chile.

We use analysis of co-citation and relative citation rates to assess the scientific strength of Chile as compared with other developing countries and to evaluate the potential for increased international collaboration between Chile and the United States in science and engineering. Co-citation is the citation of two scientific papers by a third paper. By examining frequency and patterns of co-citation, the intellectual structure and evolution of scientific disciplines and research specialties can be traced. Chile is especially "strong", as defined by the co-citation model we employ, in biomedicine and clinical medicine, and in astronomy. A relative citation rate is the ratio of the number of citations a paper receives to the average number of citations for all papers published in the same journal over time. Analysis of relative citation rates of papers published by authors with Chilean addresses show that Chilean physics, including earth and space sciences, is of unusually high quality, considerably higher than any other developing country and comparable to several industrialized countries. We conclude that Chile's scientific capacity is advanced enough to absorb and benefit significantly from strategic additions to the country's resources and capabilities for research. These would include increases in: exchanges of researchers in specific fields with U.S. and other Latin American academic, industrial, and government scientists and engineers; training at outstanding U.S. and Latin American institutions; laboratory equipment, computer time, communications links, and library materials; and funding from U.S. and international organizations. It is also apparent that Chile is strong enough in certain fields to cooperate with the U.S. in mutually beneficial international efforts.

Elevated stress hormone levels relate to Epstein-Barr virus reactivation in astronauts.

OBJECTIVE: The objective of this study was to determine the effects of stress and spaceflight on levels of neuroendocrine hormones and Epstein-Barr virus (EBV)-specific antibodies in astronauts. METHODS: Antiviral antibody titers and stress hormones were measured in plasma samples collected from 28 astronauts at their annual medical exam (baseline), 10 days before launch (L-10), landing day (R+0), and 3 days after landing (R+3). Urinary stress hormones were also measured at L-10 and R+0. RESULTS: Significant increases (p <.01) in EBV virus capsid antigen antibodies were found at all three time points (L-10, R+0, and R+3) as compared with baseline samples. Anti-EBV nuclear antigen antibodies were significantly decreased at L-10 (p <.05) and continued to decrease after spaceflight (R+0 and R+3, p <.01). No changes were found in antibodies to the nonlatent measles virus. The 11 astronauts who showed evidence of EBV reactivation had significant increases in urinary epinephrine and norepinephrine as compared with astronauts without EBV reactivation. CONCLUSION: These findings indicate that physical and psychological stresses associated with spaceflight resulted in decreased virus-specific T-cell immunity and reactivation of EBV.

Stress-induced reactivation of Epstein-Barr virus in astronauts.

Herpesviruses are leading causes of infectious blindness and death in immunocompromised individuals. Impaired cellular immunity, which is known to result in increased frequency and severity of herpesvirus infections, has been demonstrated both during and after spaceflight. Therefore, we examined whether Epstein-Barr virus (EBV), a well-characterized latent herpesvirus, undergoes reactivation in astronauts. Sera from Shuttle astronauts, taken before and after spaceflight, were examined for evidence of EBV reactivation. The geometric mean antibody titer to EBV viral capsid antigen (VCA) was significantly increased prior to flight compared to baseline (p = 0. 0001). After spaceflight, evidence of acute lytic replication was found in which 8- to 64-fold increases in EBV early antigen (EA) antibodies occurred without significant increases in antibodies to measles virus. Additionally, stress-induced shifts in circulating leukocytes and elevated levels of urinary cortisol and epinephrine were found. Overall, significant increases in EA or high VCA/EA antibody titers were found in 8 of 23 (35%) male astronauts and 3 of 5 (60%) female astronauts. These results indicate that stress reactivates EBV prior to flight and suggest that acute lytic replication of EBV occurs during spaceflight.