Endogenous oxytocin, cortisol, and testosterone in response to group singing.

Humans have sung together for thousands of years. Today, regular participation in group singing is associated with benefits across psychological and biological dimensions of human health. Here we examine the hypothesis that a portion of these benefits stem from changes in endocrine activity associated with affiliation and social bonding. Working with a young adult choir (n = 71), we measured changes salivary concentrations of oxytocin, cortisol, and testosterone from before and after four experimental conditions crossing two factors: vocal production mode (singing vs. speaking) and social context (together vs. alone). Salivary oxytocin and cortisol decreased from before to after the experimental manipulations. For oxytocin the magnitude of this decrease was significantly smaller after singing compared to speaking, resulting in concentrations that were significantly elevated after singing together compared to speaking together, after controlling for baseline differences. In contrast, the magnitude of the salivary cortisol decreases was the same across experimental manipulations, and although large, could not be separated from diurnal cycling. No significant effects were found in a low-powered exploratory evaluation of testosterone (tested only in males). At a psychological level, we found that singing stimulates greater positive shifts in self-perceived affect compared to speaking-particularly when performed together-and that singing together enhances feelings of social connection more than speaking together. Finally, measurements of heart rate made for a subset of participants provide preliminary evidence regarding physical exertion levels across conditions. These results are discussed in the context of a growing multidisciplinary literature on the endocrinological correlates of musical behavior. We conclude that singing together can have biological and psychological effects associated with affiliation and social bonding, and that these effects extend beyond comparable but non-musical group activities. However, we also note that these effects appear heavily influenced by broader contextual factors that shape social dynamics, such as stress levels, the intimacy of interactions, and the status of existing relationships.

Wide variation of winter-induced sustained thermal energy dissipation in conifers: a common-garden study.

Low temperature in winter depresses rates of photosynthesis, which, in evergreen plants, can exacerbate imbalances between light absorption and photochemical light use. Damage that could result from increased excess light absorption is minimized by the conversion of excitation energy to heat in a process known as energy dissipation, which involves the de-epoxidized carotenoids of the xanthophyll cycle. Overwintering evergreens employ sustained forms of energy dissipation observable even after lengthy periods of dark acclimation. Whereas most studies of photoprotective energy dissipation examine one or a small number of species; here, we measured the levels of sustained thermal energy dissipation of seventy conifer taxa growing outdoors under common-garden conditions at the Red Butte Garden in Salt Lake City, Utah, U.S.A. (forty nine taxa were also sampled for needle pigment content). We observed an extremely wide range of wintertime engagement of sustained energy dissipation; the percentage decrease in dark-acclimated photosystem II quantum efficiency from summer to winter ranged from 6 to 95%. Of the many pigment-based parameters measured, the magnitude of the seasonal decrease in quantum efficiency was most closely associated with the seasonal increase in zeaxanthin content expressed on a total chlorophyll basis, which explained only slightly more than one-third of the variation. We did not find evidence for a consistent wintertime decrease in needle chlorophyll content. Thus, the prevailing mechanism for winter decreases in solar-induced fluorescence emitted by evergreen forests may be decreases in fluorescence quantum yield, and wintertime deployment of sustained energy dissipation likely underlies this effect.

Body size and vocalization in primates and carnivores.

A fundamental assumption in bioacoustics is that large animals tend to produce vocalizations with lower frequencies than small animals. This inverse relationship between body size and vocalization frequencies is widely considered to be foundational in animal communication, with prominent theories arguing that it played a critical role in the evolution of vocal communication, in both production and perception. A major shortcoming of these theories is that they lack a solid empirical foundation: rigorous comparisons between body size and vocalization frequencies remain scarce, particularly among mammals. We address this issue here in a study of body size and vocalization frequencies conducted across 91 mammalian species, covering most of the size range in the orders Primates (n = 50; ~0.11-120 Kg) and Carnivora (n = 41; ~0.14-250 Kg). We employed a novel procedure designed to capture spectral variability and standardize frequency measurement of vocalization data across species. The results unequivocally demonstrate strong inverse relationships between body size and vocalization frequencies in primates and carnivores, filling a long-standing gap in mammalian bioacoustics and providing an empirical foundation for theories on the adaptive function of call frequency in animal communication.

Stability of ascorbic acid in commercially available orange juices.

OBJECTIVE: To compare the vitamin C content of reconstituted frozen orange juice concentrates at preparation to that of ready-to-drink orange juices purchased 4 to 5 weeks from expiration. DESIGN: Juices were unsealed and analyzed for reduced and oxidized vitamin C content at the time of purchase and reanalyzed 3 times weekly for 4 to 5 weeks. Same-lot samples of the ready-to-drink juices remained sealed after purchase and were opened for analyses at 3, 2, 1, or 0 weeks before expiration. SAMPLES/SETTING: Orange juices were reconstituted frozen concentrates, ready-to-drink juice packaged in resealable, screw-top containers, or ready-to-drink juice packaged in nonresealable containers. Juices were obtained from local retailers and stored at 4 degrees C in their original containers when appropriate. STATISTICAL ANALYSES PERFORMED: The reduced vitamin C content of juices analyzed repeatedly, 3 times weekly for 4 weeks, were compared using repeated measures analysis of variance. Linear regression lines were computed for reduced vitamin C in each juice over time, and differences between slopes were analyzed by oneway analysis of variance. RESULTS: The orange juices from frozen concentrates contained 86 mg reduced vitamin C per fluid cup at initial preparation and 39 to 46 mg/c after 4 weeks of storage. Ready-to-drink juices averaged significantly lower reduced vitamin C: 27 to 65 mg/c at opening and 0 to 25 mg/c at expiration 4 weeks later. Ready-to-drink orange juices had twofold to threefold higher concentrations of oxidized vitamin C vs the orange juices reconstituted from frozen, and the decomposition rate of reduced vitamin C was similar for all juices, about 2% per day once opened. APPLICATIONS: Ready-to-drink orange juices should be purchased 3 to 4 weeks before expiration date and consumed within 1 week of opening.

Autologous, cadaveric, and synthetic materials used in sling surgery: comparative biomechanical analysis.

OBJECTIVES: To compare the biomechanical properties of allografts, autografts, and synthetic materials used in sling surgery using the Instron tensinometer. METHODS: The sling grafts we studied consisted of autologous tissues (dermis, rectus fascia, and vaginal mucosa), cadaver tissues (decellularized dermis and freeze-dried, gamma-irradiated fascia lata), and synthetics (Gore-Tex and polypropylene mesh). The sling grafts were constructed into two types of slings: full strip sling (FSS) versus patch suture sling (PSS). The slings were loaded onto the Instron tensinometer and uniaxially loaded in tension until failure. From the load deformation curve, the mechanical properties of the sling grafts were compared. RESULTS: A total of 140 sling grafts were analyzed. In rank order for the FSSs, cadaver allografts had the strongest tensile strength followed by the synthetics and autologous tissues (P <0.05). The tensile strength of the FSSs was greater than for the PSSs for all groups (P

Enteral glutamine supplementation for very-low-birth-weight infants decreases hospital costs.

BACKGROUND: There is growing evidence that glutamine may be a conditionally essential amino acid for critically ill patients, including preterm infants cared for in neonatal intensive care units (NICUs). In a randomized study of 68 very-low-birth-weight (VLBW) infants, we found evidence of lower morbidity in a group fed glutamine-supplemented preterm infant formula from postnatal day 3 to day 30 than in a group fed a standard formula. We report here the effects of the glutamine supplementation on hospital costs in these infants. METHODS: The costs were analyzed by log-rank tests and Kaplan-Meier plots. RESULTS: The median costs for hospitalization, radiology, pharmacy, laboratory, and the NICU, and the median number of utilization units were reduced with glutamine supplementation. CONCLUSIONS: This study provides the first evidence for decreased hospital costs in VLBW neonates who receive enteral glutamine supplementation.

The use of relaxed eddy accumulation to measure biosphere-atmosphere exchange of isoprene and other biological trace gases.

The micrometeorological flux measurement technique known as relaxed eddy accumulation (REA) holds promise as a powerful new tool for ecologists. The more popular eddy covariance (eddy correlation) technique requires the use of sensors that can respond at fast rates (10 Hz), and these are unavailable for many ecologically relevant compounds. In contrast, the use of REA allows flux measurement with sensors that have much slower response time, such as gas chromatography and mass spectrometry. In this review, relevant micrometeorological details underlying REA are presented, and critical analytical and system design details are discussed, with the goal of introducing the technique and its potential applications to ecologists. The validity of REA for measuring fluxes of isoprene, a photochemically reactive hydrocarbon emitted by several plant species, was tested with measurements over an oak-hickory forest in the Walker Branch Watershed in eastern Tennessee. Concurrent eddy covariance measurements of isoprene flux were made using a newly available chemiluminesence instrument. Excellent agreement was obtained between the two techniques (r 2 = 0.974, n = 62), providing the first direct comparison between REA and eddy covariance for measuring the flux rate of a reactive compound. The influence of a bias in vertical wind velocity on the accuracy of REA was examined. This bias has been thought to be a source of significant error in the past. Measurements of normalized bias ([Formula: see text]) alone would lead us to think that a large potential error exists at this site. However, with our isoprene data and through simulations of REA with fast-response H2O and CO2 data, we conclude that accurate REA flux measurements can be made even in the presence of a bias in w.

Enteral glutamine supplementation for very low birth weight infants decreases morbidity.

Glutamine, described as a "conditionally essential" amino acid for critically ill patients, has not been routinely added to parenteral amino acid formulations for critically ill neonates and is provided in only small quantities by the enteral route when enteral intake is low. We conducted a blinded, randomized study of enteral glutamine supplementation in 68 very low birth weight neonates randomly assigned to receive glutamine-supplemented premature formula versus premature formula alone between days 3 and 30 of life. Primary end points consisted of hospital-acquired sepsis, tolerance to subsequent enteral feedings (days with no oral intake), and duration of hospital stay. Hospital acquired sepsis was 30% (control group) and 11% (glutamine group). Logistic regression with birth weight as a covariate showed that: (1) feeding group was significant (p = 0.048) in determining the probability of developing proven sepsis over the course of hospitalization and (2) the estimated odds of developing sepsis were 3.8 times higher for infants in the control group than for those treated with glutamine. Glutamine-supplemented infants had better tolerance to enteral feedings as measured by percent of days on which feedings needed to be withheld (mean percentage of 8.8 vs 23.8, p = 0.007). Analysis of T cells demonstrated a blunting of the rise in HLA-DR+ and CD16 subsets in glutamine-supplemented infants. There were no differences in growth; in serum ammonia, urea, liver transaminase, or prealbumin concentrations; or in mean hospital stay. This study provides evidence for decreased morbidity in very-low-birth-weight neonates who receive enteral glutamine supplementation.

Zinc status is not adversely affected by folic acid supplementation and zinc intake does not impair folate utilization in human subjects.

Changes in zinc status in response to folic acid supplementation and the effect of zinc intake on folate utilization were evaluated in 12 men (20-34 y old) consuming a diet containing 3.5 or 14.5 mg zinc/d for two 25-d intervals. Deuterium-labeled folic acid (800 micrograms/d) or a placebo was administered orally during each phase. No differences in plasma zinc, erythrocyte zinc, urinary zinc, erythrocyte metallothionein or serum alkaline phosphatase, due to supplemental folic acid, were detected at either level of zinc intake. Differences in the response to folic acid supplementation, due to the level of zinc intake, were not detected for serum, erythrocyte or urinary (labeled and unlabeled) folate. Within the constraints of this short-term folic acid supplementation study, adverse effects on zinc status were not observed and our data suggest that folic acid utilization was not influenced by level of zinc intake.

Intraductal tetracycline therapy for the treatment of chronic recurrent parotitis.

Chronic recurrent parotitis (CRP) is recurrent parotid inflammation with non-obstructive sialectasis. Therapies which produce acinar atrophy or remove the acini are effective in treating CRP. Parotidectomy, tympanic neurectomy, duct ligation, and radiation therapy have either a low success rate or a high risk of morbidity. Intraductal antibiotic instillation has been proposed as a possible method of treatment. We hypothesized that the cytotoxic effects of tetracycline could produce acinar atrophy. A double-blind experiment of intraductal tetracycline instillation was performed in ten rabbits. Acinar atrophy and acute inflammation were found in 40% of the tetracycline treated glands; controls had a complete absence of these histologic changes. These results support the use of tetracycline instillation to produce acinar atrophy and therefore, intraductal tetracycline may be an effective, low-risk therapy for CRP. The clinical features of CRP will be reviewed and therapeutic implications discussed.

Evaluation of capillary supercritical fluid chromatography with mass spectrometric detection for the analysis of a drug (mebeverine) in a dog plasma matrix.

Supercritical fluid chromatography with mass spectrometric detection was evaluated as a technique for the analysis of drugs in biological fluids. Dog plasma was spiked with a model drug, mebeverine, and with a deuterium-labeled analog of mebeverine. The spiked plasma was prepared for analysis by solid-phase extraction on octadecylsilane cartridges. Mebeverine levels in the spiked dog plasma samples were determined by interpolation from a standard curve. Accuracy and precision of the analysis were determined within and between days. In general, accuracy was found to be 100 +/- 15% for plasma samples spiked with 6 to 60 ng mebeverine/ml. The relative standard deviation for replicate sample analysis over this concentration range was between 5 and 12.5%.

ON and OFF activity gradients in the lateral geniculate nucleus of the cat: a combined 14C 2-deoxyglucose and D,L-2-amino-4-phosphonobutyric acid study.

Experiments on the lateral geniculate nucleus (LGN) of the cat based on 14C 2-deoxyglucose (2-DG) autoradiography and intraocular injections of 2-amino-4-phosphonobutyric acid (APB) provided evidence for gradients of metabolic activity in the ON and OFF pathways in layer A, but only very weakly, if at all, in layer A1. Alert and freely moving cats were exposed to square-wave gratings over a 45-min period after injection of the 2-DG. When one eye had been treated previously with APB, contralateral layer A showed a clear gradient of 2-DG label indicating that the remaining OFF pathway was most active ventrally in the layer and, by implication, that the ON pathway is normally most active dorsally. No gradient was apparent in layer A1 ipsilateral to the APB eye. Control experiments based on binocular injections of tetrodotoxin (TTX) demonstrated that no gradients were present in the baseline activity within the layers. Finally, monocular injections of TTX provided evidence for gradients of nondominant eye activity in layers A and A1 that were maximal near the interlaminar zone between layers A and A1 and declined in mirror-symmetric fashion toward the dorsal border of A and the ventral border of A1. Combined with earlier anatomical studies showing depth-dependent patterns of geniculo-cortical projection, these results indicate that in the cat, as in several other species, the visual input to striate cortex is partly organized around ON and OFF pathways. In addition, the results suggest that a systematic variation of binocular interaction, perhaps related to ocular dominance, exists through the depths of the geniculate layers.(ABSTRACT TRUNCATED AT 250 WORDS)

Meconium passage in very-low-birth-weight infants.

The timing of the first meconium stool has been considered a marker for proper gastrointestinal functioning in the term infant. There is limited information on the meconium passage patterns of very-low-birth-weight infants of less than 32 weeks' gestation. It is unknown whether feeding practices influence the timing of the first stool in these infants. We retrospectively studied 47 very-low-birth-weight infants with birth weights of 1250 g or less who were previously enrolled in a study of gastrointestinal (GI) priming. Infants whose mothers desired to breast feed (n = 7) were given GI priming with their own mother's milk. The remaining infants had been randomly assigned to receive total parenteral nutrition alone (n = 21) or GI priming with infant formula (n = 19) during the first 14 days of life. We attempted to advance all infants to full enteral nutrition by 21 days of age. There was no statistically significant difference in timing of the first stool among the three groups. The overall median age at first stool was 43 hours, and the 75th percentile was 10 days. The range was 1/2 hour to 27 days. There was no concordance between time of first stool and birth weight within the range studied. There was no concordance between time of first stool and necrotizing enterocolitis, although there was little statistical power to detect this. There was also very little concordance with feeding tolerance. Other than necrotizing enterocolitis, no significant GI disease developed in any of the infants studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Spatial memory deficits in aged rats: contributions of monoaminergic systems.

Age-dependent changes in monoaminergic systems and their relationship to senescent memory decline were investigated in 4- and 25-26-month-old, female, Fischer 344 rats. Spatial memory performance was tested on an 8-arm radial maze, and levels of norepinephrine (NE), dopamine (DA) and metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid, serotonin (5-HT) and metabolite 5-hydroxyindoleacetic acid were measured in brain areas which contribute to memory function--basal forebrain cholinergic nuclei, subfields of the hippocampus, frontal and entorhinal cortex--and in monoaminergic cell body areas. The performance of aged subjects was significantly impaired as compared to young subjects, and alterations of 20-60% in monoamine and metabolite levels were measured in specific brain areas of aged rats. Decreased NE levels were found in basal forebrain nuclei and cortical areas but not in hippocampal subfields of aged rats. Changes in the 5-HT system were present in hippocampal, cortical and basal forebrain sites. Changes in the DA system were the most pervasive with aged rats showing decreased DA and/or metabolites in several basal forebrain nuclei, cortical areas, and the hippocampus. Aged rats showed 50% decreases of monoamines in locus coeruleus and substantia nigra and 30% decreases in the dorsal raphe nucleus. Some but not all of the changes correlated with memory performance. The present results in rats support evidence that age-dependent changes in monoaminergic function in discrete brain sites contribute to senescent memory decline and suggest that monoaminergic-cholinergic interactions within basal forebrain nuclei may be important in this decline.

Three-dimensional form and a simple, interrupted flat map of a single layer in the lateral geniculate nucleus of the cat.

A simple, computer-based procedure is described for measuring the 3-dimensional (3D) coordinates and making two-dimensional (2D) flat maps of a curved surface representing the middle depth of layer A1 in the lateral geniculate nucleus (LGN) of the cat. The surface was defined from histological sections and flattened by tiling it with small triangular tiles which were then laid in a single plane to form several flat strips or lunes. Though the resultant maps are discontinuous (interrupted), they preserve total area to within a few percent, have constant scales throughout and closely approximate true shape within individual tiles. The results represent a step in assessing the potential contribution of form to visual function in the LGN. They provide graphic 3D and 2D images of the complex shape of a single layer and a quantitative framework for constructing models of geniculocortical processing that can incorporate the 3D form of the LGN as well as other anatomical and physiological data.

Evidence for sublaminar organization of the cells of origin of the geniculo-striate pathway in the cat: a novel method for cortical deposition of HRP.

A novel technique for retrograde labelling was used to trace the axonal projections from the lateral geniculate nucleus (LGN) to the striate cortex in the cat. Cortical deposits of horseradish peroxidase were made in the form of long straight lines oblique to layer IV. The projections along the lengths of these linear deposits were inferred, by retinotopic correspondence, from the distributions of the retrogradely labelled cells in the LGN. The results are consistent with an earlier report, by Humphrey et al., that the depths of axon terminations in layer IV reflect the depths of the parent cell bodies in layers A and A1 of the LGN. The pattern observed in the present experiments--border cells in the A layers project mainly to cortical layers IVa and centre cells to IVb--suggests that: (1) the sublaminar segregation of the ON and OFF pathways that occurs in the cat LGN is reversed by convergent projections to IVa from the dorsal (ON-rich) and ventral (OFF-rich) borders of the A layers, and (2) the paucity of Y input to IVb is due to the near absence of Y cells in the narrow central sublaminae of the A layers that supply the main input to IVb.

ON/OFF organization in the cat lateral geniculate nucleus: sublaminae vs. columns.

The hypothesis was tested that ON and OFF cells in the A layers of the cat's lateral geniculate nucleus (l.g.n.) form separate ON and OFF columns, and new evidence for their sublaminar distributions is presented. Evidence for columns was sought in previously published results from 184 electrode tracks oriented parallel to the layers and in new experiments, based on multiple, closely spaced electrode tracks oriented vertically to the layers. The tracks parallel to the layers were analyzed in two ways. First, the distances between cells of like-sign and unlike-sign were measured. Second, the signs of response of cells above and below one another, from pairs of tracks made simultaneously in the same layer, were compared. The analyses, which included computer simulations of the experiments based on columnar and noncolumnar models, provided no evidence for columns. The results from the closely spaced, vertical tracks also failed to show columns but confirmed that the organization of ON and OFF cells in the layers is fundamentally sublaminar.

Timing differences between the light responses of X cells recorded simultaneously in cat lateral geniculate nucleus.

Using two microelectrodes, recordings were made from pairs of like-signed cells at different depths in single layers (A or A1) of the cat's lateral geniculate nucleus (LGN). The cells were chosen to have near or overlapping receptive fields so that they could be stimulated simultaneously with a single spot or bar of light. Under these controlled conditions, paired X cells (n = 32 pairs) showed differences in latency from less than 10 to about 80 ms, but no latency differences were observed between paired Y cells (n = 3 pairs). Within XY pairs (n = 11) the Y cells responded faster than the X cells. A separate analysis of previously reported, singly recorded X cells (n = 131) also showed wide differences in X cell latencies. The results confirm that temporal differences in signalling occur within the X pathway in the cat LGN (Mastronarde, 1981, 1987a; Humphrey & Weller, 1988a) and they show explicitly that the differences occur simultaneously, in single layers and at single retinotopic loci. No consistent relationship was found between timing and depth, but the possibility of weak, depth-dependent trends is considered in the Discussion.

Differences in the amplitude of X-cell responses as a function of depth in layer A of lateral geniculate nucleus in cat.

1. Extracellular recordings were made from 131 X-like cells (hereafter called X cells) at different depths in layer A of the lateral geniculate nucleus (l.g.n.) in the cat. The depths of the cells were measured accurately by orienting the electrodes parallel to the borders of the layer and reconstructing the electrode tracks from histological sections. 2. Each cell was stimulated with a standardized stimulus; a 500 ms, low-contrast (10%) spot of light, matched in size to the centres of the receptive fields. The responses were later compared with the depths of the cells in the layer. 3. The amplitudes of the responses, which ranged between peak values of 20 and 400 spikes/s in different cells, were related to the depths of the cells in the layer. On average, the response amplitudes of the X-on cells near the borders of the layer were small compared to those in the middle. The responses of the X-off cells were reciprocal; large near the borders of the layer and small in the middle. 4. The results reveal a sublaminar organization in layer A based on the signs and amplitudes of X-cell responses. It is suggested that the pattern reflects differences in signalling within the X-on and X-off channels that are preserved in the relay to the visual cortex.