In an arms race between host and parasite, a lungworm's ability to infect a toad is determined by host susceptibility not parasite preference.

Evolutionary arms races can alter both parasite infectivity and host resistance, and it is difficult to separate the effects of these twin determinants of infection outcomes. We used a co-introduced, invasive host-parasite system (the lungworm Rhabdias pseudosphaerocephala and cane toads Rhinella marina), where rapid adaptation and dispersal have led to population differences in infection resistance. We quantified behavioural responses of parasite larvae to skin-chemical cues of toads from different invasive populations, and rates at which juvenile hosts became infected following standardized exposure to lungworms. Chemical cues from toad skin altered host-seeking behaviour by parasites, similarly among populations. The number of infection attempts (parasite larvae entering the host's body) also did not differ between populations, but rates of successful infection (establishment of adult worm in host lungs) were higher for range-edge toads than for range-core conspecifics. Thus, lower resistance to parasite infection in range-edge juvenile toads appears to be due to less effective immune defences of the host rather than differential behavioural responses of the parasite. In this ongoing host-parasite arms race, changing outcomes appear to be driven by shifts in host immunocompetence.

The value of pre-donation pulse assessment for apheresis donors.

OBJECTIVES: During apheresis, donors have up to 6 · 5 L of blood processed and receive citrated plasma during the return cycle. It is of concern that a donor with an unrecognised significant cardiac abnormality might therefore be put at further risk during apheresis. BACKGROUND: Apheresis donors with cardiac abnormalities may be at increased risk of severe adverse reactions as a result of repeated volume loss or the adverse effect of citrate anticoagulant on cardiac contractility as the result of reduction in ionised calcium. An abnormal rate or rhythm may indicate a cardiac abnormality. METHODS: At two donation centres between May 2001 and April 2009, the pulse rate and rhythm of every donor was measured before each apheresis procedure they underwent. Donors with a pulse rate outside the range 50-100 beats per minute and/or pulse irregularity were deferred from donation and referred to their general practitioner (GP). RESULTS: Data from 3945 apheresis donors (3874 platelet donors, 71 plasma donors, 3595 males, 350 females) were reviewed. Two hundred thirty-eight donors (6%) were identified as having abnormal pulses and were referred to their GP. Eighty-one donors had bradycardia, 16 had tachycardia and 141 had an irregular pulse. Fifteen of the 3945 donors (0 · 4%) were found to have significant cardiac disease and withdrawn from the donor panel. CONCLUSIONS: By simple monitoring, donors who may be at increased risk from the apheresis procedure can be identified. By performing pre-donation pulse assessment of all apheresis donors, we fulfil our medicolegal duty by not putting donors at avoidable risk.

Single-electron capacitance spectroscopy of individual dopants in silicon.

Motivated by recent transport experiments and proposed atomic-scale semiconductor devices, we present measurements that extend the reach of scanned-probe methods to discern the properties of individual dopants tens of nanometers below the surface of a silicon sample. Using a capacitance-based approach, we have both spatially resolved individual subsurface boron acceptors and detected spectroscopically single holes entering and leaving these minute systems of atoms. A resonance identified as the B+ state is shown to shift in energy from acceptor to acceptor. We examine this behavior with respect to nearest-neighbor distances. By directly measuring the quantum levels and testing the effect of dopant-dopant interactions, this method represents a valuable tool for the development of future atomic-scale semiconductor devices.

Intergenerational effects of manipulating DNA methylation in the early life of an iconic invader.

In response to novel environments, invasive populations often evolve rapidly. Standing genetic variation is an important predictor of evolutionary response but epigenetic variation may also play a role. Here, we use an iconic invader, the cane toad (Rhinella marina), to investigate how manipulating epigenetic status affects phenotypic traits. We collected wild toads from across Australia, bred them, and experimentally manipulated DNA methylation of the subsequent two generations (G1, G2) through exposure to the DNA methylation inhibitor zebularine and/or conspecific tadpole alarm cues. Direct exposure to alarm cues (an indicator of predation risk) increased the potency of G2 tadpole chemical cues, but this was accompanied by reductions in survival. Exposure to alarm cues during G1 also increased the potency of G2 tadpole cues, indicating intergenerational plasticity in this inducible defence. In addition, the negative effects of alarm cues on tadpole viability (i.e. the costs of producing the inducible defence) were minimized in the second generation. Exposure to zebularine during G1 induced similar intergenerational effects, suggesting a role for alteration in DNA methylation. Accordingly, we identified intergenerational shifts in DNA methylation at some loci in response to alarm cue exposure. Substantial demethylation occurred within the sodium channel epithelial 1 subunit gamma gene (SCNN1G) in alarm cue exposed individuals and their offspring. This gene is a key to the regulation of sodium in epithelial cells and may help to maintain the protective epidermal barrier. These data suggest that early life experiences of tadpoles induce intergenerational effects through epigenetic mechanisms, which enhance larval fitness. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'

Study of iron stores in regular plateletpheresis donors.

Plateletpheresis donors will lose up to 100 mL of blood at each donation, leading to concern that they may become iron deficient, particularly if donating at the maximum allowed frequency under National Blood Service policy of every 2 weeks. The serum ferritin levels of 508 regular plateletpheresis donors and 101 non-donors were measured to indicate the level of their iron stores. About 33.9% (156/460) of platelet donors had depleted iron stores compared with 3.1% (3/97) non-donors. Results for male and post-menopausal female donors were similar with 36.2% (131/362) of males and 37.7% (20/53) of post-menopausal females showing iron depletion. There was clear correlation with donation frequency in males with 63.9% (46/72) of males donating at 2 weekly intervals found to be iron depleted. The percentage of iron depleted male subjects decreased as donation intervals increased. Correlation with lifetime donations of platelets was not demonstrated, although no donor who had given fewer than 14 blood and/or platelet donations was found to be iron depleted. In males there was a clear correlation between iron depletion and frequency of donation. There appeared to be no correlation with lifetime number of platelet donations. As a result of this study, we have advised that volunteers should not donate platelets more than 15 times per year, so that red cell loss is no more than the equivalent of three whole blood donations (1500 mL).

Do Epigenetic Changes Drive Corticosterone Responses to Alarm Cues in Larvae of an Invasive Amphibian?

The developmental environment can exert powerful effects on animal phenotype. Recently, epigenetic modifications have emerged as one mechanism that can modulate developmentally plastic responses to environmental variability. For example, the DNA methylation profile at promoters of hormone receptor genes can affect their expression and patterns of hormone release. Across taxonomic groups, epigenetic alterations have been linked to changes in glucocorticoid (GC) physiology. GCs are metabolic hormones that influence growth, development, transitions between life-history stages, and thus fitness. To date, relatively few studies have examined epigenetic effects on phenotypic traits in wild animals, especially in amphibians. Here, we examined the effects of exposure to predation threat (alarm cues) and experimentally manipulated DNA methylation on corticosterone (CORT) levels in tadpoles and metamorphs of the invasive cane toad (Rhinella marina). We included offspring of toads sampled from populations across the species' Australian range. In these animals, exposure to chemical cues from injured conspecifics induces shifts in developmental trajectories, putatively as an adaptive response that lessens vulnerability to predation. We exposed tadpoles to these alarm cues, and measured changes in DNA methylation and CORT levels, both of which are mechanisms that have been implicated in the control of phenotypically plastic responses in tadpoles. To test the idea that DNA methylation drives shifts in GC physiology, we also experimentally manipulated methylation levels with the drug zebularine. We found differentially methylated regions (DMRs) between control tadpoles and their full-siblings exposed to alarm cues, zebularine, or both treatments. However, the effects of these manipulations on methylation patterns were weaker than clutch (e.g., genetic, maternal, etc.) effects. CORT levels were higher in larval cane toads exposed to alarm cues and zebularine. We found little evidence of changes in DNA methylation across the GC receptor gene (NR3C1) promoter region in response to alarm cue or zebularine exposure. In both alarm cue and zebularine-exposed individuals, we found differentially methylated DNA in the suppressor of cytokine signaling 3 gene (SOCS3), which may be involved in predator avoidance behavior. In total, our data reveal that alarm cues have significant impacts on tadpole physiology, but show only weak links between DNA methylation and CORT levels. We also identify genes containing DMRs in tadpoles exposed to alarm cues and zebularine, particularly in range-edge populations, that warrant further investigation.

Single and multigenerational responses of body mass to atmospheric oxygen concentrations in Drosophila melanogaster : evidence for roles of plasticity and evolution.

Greater oxygen availability has been hypothesized to be important in allowing the evolution of larger invertebrates during the Earth's history, and across aquatic environments. We tested for evolutionary and developmental responses of adult body size of Drosophila melanogaster to hypoxia and hyperoxia. Individually reared flies were smaller in hypoxia, but hyperoxia had no effect. In each of three oxygen treatments (hypoxia, normoxia or hyperoxia) we reared three replicate lines of flies for seven generations, followed by four generations in normoxia. In hypoxia, responses were due primarily to developmental plasticity, as average body size fell in one generation and returned to control values after one to two generations of normoxia. In hyperoxia, flies evolved larger body sizes. Maximal fly mass was reached during the first generation of return from hyperoxia to normoxia. Our results suggest that higher oxygen levels could cause invertebrate species to evolve larger average sizes, rather than simply permitting evolution of giant species.

Achievement of thermal stability by varying metabolic heat production in flying honeybees.

Thermoregulation of the thorax allows endothermic insects to achieve power outputs during flight that are among the highest in the animal kingdom. Flying endothermic insects, including the honeybee Apis mellifera, are believed to thermoregulate almost exclusively by varying heat loss. Here it is shown that a rise in air temperature from 20 degrees to 40 degrees C causes large decreases in metabolic heat production and wing-beat frequency in honeybees during hovering, agitated, or loaded flight. Thus, variation in heat production may be the primary mechanism for achieving thermal stability in flying honeybees, and this mechanism may occur commonly in endothermic insects.

Effects of developmental stress on animal phenotype and performance: a quantitative review.

Developmental stressors are increasingly recognised for their pervasive influence on the ecology and evolution of animals. In particular, many studies have focused on how developmental stress can give rise to variation in adult behaviour, physiology, and performance. However, there remains a poor understanding of whether general patterns exist in the effects and magnitude of phenotypic responses across taxonomic groups. Furthermore, given the extensive phenotypic variation that arises from developmental stressors, it remains important to ascertain how multiple processes may explain these responses. We compiled data from 111 studies to examine and quantify the effect of developmental stress on animal phenotype and performance from juveniles to adulthood, including studies from birds, reptiles, fish, mammals, insects, arachnids, and amphibians. Using meta-analytic approaches, we show that across all studies there is, on average, a moderate to large negative effect of developmental stress exposure (posterior mean effect: |d| = -0.51) on animal phenotype or performance. Additionally, we demonstrate that interactive effects of timing of stressor onset and the duration of exposure to stressors best explained variation in developmental stress responses. Animals exposed to stressors earlier in development had more-positive responses than those with later onset, whereas longer duration of exposure to a stressor caused responses to be stronger in magnitude. However, the high amount of heterogeneity in our results, and the low degree of variance explained by fixed effects in both the meta-analysis (R2 = 0.034) and top-ranked meta-regression model (R2 = 0.02), indicate that phenotypic responses to developmental stressors are likely highly idiosyncratic in nature and difficult to predict. Despite this, our analyses address a critical knowledge gap in understanding what effect developmental stress has on phenotypic variation in animals. Additionally, our results highlight important environmental and proximate factors that may influence phenotypic responses to developmental stressors.

Impairment of short-term memory associated with low iron stores in a volunteer multidose plateletpheresis donor.

A platelet donor may lose 80-100 mL of blood both in the harness and by blood sampling at each donation, the equivalent of four to five whole blood donations per annum for a donor attending at 2-weekly intervals. A 54-year-old male multidose platelet donor had donated platelets at regular 2-weekly intervals for 6 years. He developed an impairment of anterograde memory (new learning). A self-rating scale revealed a moderate degree of depression [Beck Depression Inventory (BDI) score 22]. Memory testing (Doors and People Memory Battery) showed low scores, particularly for verbal recall and verbal recognition memory. He was found to have a normal haemoglobin of 157 g L(-1) with normal red blood cell indices, but a low serum ferritin (15 ng mL(-1)) and a low serum iron (8.1 mmol L(-1)). Following iron therapy and a return of his iron stores to normal levels, there was an improved BDI score of 13 (minimal level of depression) and a marked improvement in memory test scores. This has been maintained even though he has resumed platelet donation but at reduced intervals.

Mitochondrial DNA repair: a critical player in the response of cells of the CNS to genotoxic insults.

Cells of the CNS are constantly exposed to agents which damage DNA. Although much attention has been paid to the effects of this damage on nuclear DNA, the nucleus is not the only organelle containing DNA. Within each cell, there are hundreds to thousands of mitochondria. Within each mitochondrion are multiple copies of the mitochondrial genome. These genomes are extremely vulnerable to insult and mutations in mitochondrial DNA (mtDNA) have been linked to several neurodegenerative diseases, as well as the normal process of aging. The principal mechanism utilized by cells to avoid DNA mutations is DNA repair. Multiple pathways of DNA repair have been elucidated for nuclear DNA. However, it appears that only base excision repair is functioning in mitochondria. This repair pathway is responsible for the removal of most endogenous damage including alkylation damage, depurination reactions and oxidative damage. Within the rat CNS, there are cell-specific differences mtDNA repair. Astrocytes exhibit efficient repair, whereas, other glial cell types and neuronal cells exhibit a reduced ability to remove lesions from mtDNA. Additionally, a correlation was observed between those cells with reduced mtDNA repair and an increase in the induction of apoptosis. To demonstrate a causative relationship, a strategy of targeting DNA repair proteins to mitochondria to enhance mtDNA repair capacity was employed. Enhancement of mtDNA repair in oligodendrocytes provided protection from reactive oxygen species- and cytokine-induced apoptosis. These experiments provide a novel strategy for protecting sensitive CNS cells from genotoxic insults and thus provide new treatment options for neurodegenerative diseases.

Barriers to providing diabetes care in community health centers.

OBJECTIVE: We aimed to identify barriers to improving care for individuals with diabetes in community health centers. These findings are important because many such patients, as in most other practice settings, receive care that does not meet evidence-based standards. RESEARCH DESIGN AND METHODS: In 42 Midwestern health centers, we surveyed 389 health providers and administrators about the barriers they faced delivering diabetes care. We report on home blood glucose monitoring, HbA1c tests, dilated eye examinations, foot examinations, diet, and exercise, all of which are a subset of the larger clinical practice recommendations of the American Diabetes Association (ADA). RESULTS: Among the 279 (72%) respondents, providers perceived that patients were significantly less likely than providers to believe that key processes of care were important (overall mean on 30-point scale: providers 26.8, patients 18.2, P = 0.0001). Providers were more confident in their ability to instruct patients on diet and exercise than on their ability to help them make changes in these areas. Ratings of the importance of access to care and finances as barriers varied widely; however, >25% of the providers and administrators agreed that significant barriers included affordability of home blood glucose monitoring, HbA1c testing, dilated eye examination, and special diets; nonproximity of ophthalmologist; forgetting to order eye examinations and to examine patients' feet; time required to teach home blood glucose monitoring; and language or cultural barriers. CONCLUSIONS: Providers in health centers indicate a need to enhance behavioral change in diabetic patients. In addition, better health care delivery systems and reforms that improve the affordability, accessibility, and efficiency of care are also likely to help health centers meet ADA standards of care.

Pharmacokinetics and pharmacodynamics of recombinant factor VIIa.

OBJECTIVE: To evaluate the pharmacokinetics and pharmacodynamics of recombinant activated factor VII (rFVIIa). METHODS: Single-dose pharmacokinetics of three dose levels (17.5, 35, and 70 micrograms/kg) of rFVIIa were investigated in 15 patients with hemophilia with severe factor VIII or factor IX deficiency (with or without inhibitors) while they were in the nonbleeding state and during bleeding episodes. Factor VII clotting activity (FVII:C) was determined 5 minutes before and at 10, 20, and 50 minutes and 2, 4, 6, 8, 12, and 24 hours after rFVIIa administration. Model-independent pharmacokinetic analysis of FVII:C plasma concentration-time data included determination of plasma clearance, mean residence time, and volume of distribution. rFVIIa recovery was determined from the plasma FVII:C observed 10 minutes after administration. Pharmacodynamic assessments of prothrombin time, activated partial thromboplastic time, and Factor X values obtained concurrently with FVII:C samples were performed. RESULTS: Sufficient data to allow pharmacokinetic parameter calculation were available for 25 nonbleeding episodes in 11 patients (17.5 micrograms/kg, n = 8; 35 micrograms/kg, n = 9; 70 micrograms/kg, n = 8) and for five bleeding episodes in three patients (17.5 micrograms/kg, n = 2; 35 micrograms/kg, n = 2; 35 micrograms/kg, n = 1). Recovery was calculated during 27 nonbleeding and 17 bleeding episodes. rFVIIa distribution volume is two to three times that of plasma. Median clearance was low--31.0 ml/hr.kg in nonbleeding episodes and 32.5 mg/hr.kg in bleeding episodes. In nonbleeding episodes, median mean residence time was 3.44 hours and median half-life was 2.89 hours. In bleeding episodes, the elimination rate appears to be higher, with a median mean residence time of 2.97 hours and a median half-life of 2.30 hours. Recovery was 45.6% during nonbleeding conditions and 43.5% during bleeding episodes (p = 0.0006); it was statistically lower with the highest dose level than with the 17.5 and 35 micrograms/kg doses (p = 0.007). A significant statistical relationship was observed between values of the prothrombin time and activated partial thromboplastin time, and values of FVII:C with use of maximum effect model. CONCLUSIONS: The pharmacokinetics of rFVIIa are linear in the dose range evaluated. The results suggest potential value of prothrombin time determination in the monitoring of rFVIIa therapy.

Adult Fanconi syndrome with monoclonal abnormality of immunoglobulin light chain.

Two adult cases of the Fanconi syndrome are described, in each of which there was abnormal urinary excretion of immunoglobulin kappa-chain. The significance of this finding is discussed in relation to the recognized association between multiple myeloma and the Fanconi syndrome.

Lysozymuria and acute disorders of renal function.

On the assumption that increased urinary lysozyme concentration (;lysozymuria') indicates tubular proteinuria and therefore impaired tubular function, urinary lysozyme has been estimated in acute disorders where transient disturbances of renal function might be expected, in cases diagnosed clinically as extrarenal uraemia, and in a few examples of acute renal disease. Reversible lysozymuria occurred with hypokalaemia, postoperative ;collapse', electrolyte depletion, severe extrarenal infection, acute pyelonephritis, the nephrotic syndrome, after a few apparently uncomplicated surgical operations, and very transiently after ventricular fibrillation abolished by DC shock. There was no lysozymuria with severe uraemic heart failure, aspirin and paracetamol poisoning, or severe jaundice, nor in two cases of acute glomerulonephritis. Although lysozymuria may occasionally be useful in the clinical diagnosis of acutely disordered renal function, the results suggest that its value is limited; on the other hand, they have provided information on renal pathophysiology in acute disease.

Safety and initial clinical efficacy of three dose levels of recombinant activated factor VII (rFVIIa): results of a phase I study.

The safety and efficacy of recombinant DNA-produced factor VIIa (rFVIIa) was investigated in 15 haemophilic patients in non-bleeding states and during bleeding episodes (mild to moderate joint bleed). Patients with severe haemophilia A without inhibitors (n = 4), haemophilia A with inhibitors (n = 10), and haemophilia B with inhibitor (n = 1) received one or more doses of rFVIIa during 32 non-bleeding study episodes and 23 bleeding episodes. The study was an open, uncontrolled, dose-escalation (17.5 micrograms/kg, 35 micrograms/kg, 70 micrograms/kg) trial. Physical evaluation, laboratory assessment, and immunology testing were conducted at baseline, monthly for 3 months and every 3 months thereafter. The immediate safety of rFVIIa was assessed by monitoring of D-dimer, fibrinogen, platelet count, antithrombin III, thrombin-antithrombin complex, and alpha 2-antiplasmin 5 min before and at multiple times throughout the following 24 h. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) values were also obtained. Pain, swelling, joint circumference, and range of motion were recorded before administration of the initial dose of rFVIIa in bleeding patients and at 6, 12, and 24 h. Haemostatic response to rFVIIa was observed in patients with severe VIII and IX deficiency with and without inhibitors. Therapy with rFVIIa was judged effective in 19 of the 22 evaluable bleeding episodes at one or more time points. The 35 micrograms/kg and 70 micrograms/kg doses were associated with higher response rates at 6 and 12 h compared to the 17.5 micrograms/kg dose level. A second dose of rFVIIa was administered in 20 of the 22 bleeding episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

The beneficial acclimation hypothesis versus acclimation of specific traits: physiological change in water-stressed Manduca sexta caterpillars.

Do organisms make beneficial physiological adjustments in response to environmental change? We examined this question by measuring the effects of short-term (12-36 h) and long-term (larval lifetime) hydric stress on the tobacco hornworm, Manduca sexta. Larvae were reared from the first instar on low-water (69%) or high-water (80%) artificial diets and then transferred early in the fifth instar to the same or opposite diet (2x2 design). Within the subsequent 36 h, we measured 24-h growth rates and three primary determinants of the water budget: water gain via consumption and water loss via evaporation and defecation. Larvae preexposed to low-water diet grew less rapidly on low-water diet than those switched acutely to low-water diet from high-water diet, showing that larvae preexposed to a particular environment do not necessarily acclimate beneficially to that environment. Our data on water fluxes to and from larvae, however, strongly suggest that water-stressed larvae did make beneficial physiological adjustments. Larvae responded to short-term hydric stress by minimizing rates of water excretion, primarily by increasing rates of rectal water absorption. Larvae responded to chronic water stress by significantly reducing rates of evaporative water loss; they also showed additional reductions in fecal water excretion, but these decreases were due to lowered consumption and not to further increases in rate of rectal water absorption. This mismatch between maladaptive acclimation of organismal performance and beneficial adjustment of suborganismal traits can be reconciled by recognizing that organismal physiology is hierarchical: fitness-related performance traits represent the aggregate outcome of numerous, more mechanistic physiological traits. Although chronic exposure to an environment may depress the aggregate effect of these mechanistic traits on performance, organisms are not precluded from making beneficial adjustments to individual traits contributing to performance.

Interactive effects of rearing temperature and oxygen on the development of Drosophila melanogaster.

Although higher temperatures strongly stimulate ectothermic metabolic rates, they only slightly increase oxygen diffusion rates and decrease oxygen solubility. Consequently, we predicted that insect gas exchange systems would have more difficulty meeting tissue oxygen demands at higher temperatures. In this study, Drosophila melanogaster were reared from egg to adult in hyperoxic (40%), hypoxic (10%), and normoxic (21%) conditions and in temperatures ranging from 15 degrees -31.5 degrees C to examine the interactive effect of temperature and oxygen on development. Hyperoxia generally increased mass and growth rate at higher rearing temperatures. At lower rearing temperatures, however, hyperoxia had a very small effect on mass, did not affect growth rate, and lengthened time to eclosion. Relative to normoxia, flies reared in hypoxic conditions were generally smaller (mass and thorax length), had longer eclosion times, slower growth rates, and reduced survival. At cooler temperatures, hypoxia had relatively modest or nonsignificant effects on development, while at higher temperatures, the effects of hypoxia were large. These results suggest that higher temperatures reduce oxygen delivery capacity relative to tissue oxygen needs, which may partially explain why ectotherms are smaller when development occurs at higher temperatures.

Effects of diet on titratable acid-base excretion in grasshoppers.

Despite the potential for diet to affect organismal acid-base status, especially in herbivores, little is known about the effects of diet on acid-base loading and excretion. We tested the effects of diet on acid-base loading and excretion in grasshoppers by (a) comparing the fecal acid-base content of 15 grasshopper species collected from the field and (b) comparing fecal acid-base excretion rates of Schistocerca americana grasshoppers fed vegetable diets that differed in their ashed and raw acid-base contents. The field experiments indicated that grass-feeding species excrete fairly neutral fecal pellets, while forb/mixed-feeding species vary widely in their fecal acid-base contents. In the laboratory experiment, acid-base excretion rates were positively correlated with dietary ashed base intake rates but were not correlated with the acid-base content of raw, unashed diet or feeding rate. These experiments suggest that some diets could strongly challenge the acid-base homeostasis of herbivores; in some grasshoppers, dietary acid-base loads could produce certainly lethal 1-unit changes in average body pH within 6 h if they were not excreted.

Effect of music and auditory stimuli on secretory immunoglobulin A (IgA).

This study investigated the effects of music and an auditory stimulus on immunoglobulin A (IgA). Groups of college students (N = 66) were exposed to one of four conditions: a 30-min, tone/click presentation; 30 min. of silence; 30 min, of a Muzak tape referred to as "Environmental Music"; and a 30-min. radio broadcast comparable in musical style. Saliva samples collected before and after each 30-min. treatment were assayed for IgA. Analysis indicated significant increases in IgA for the Muzak condition (n = 20) but not for any of the other conditions. Possible mechanisms of action and implications for immunocompetence are discussed.