Judgement bias testing in group-housed gestating sows.

Societal concerns about animal welfare have triggered the movement of gestating sows from individual stalls to group housing in many countries. Common methods of assessing sow welfare focus on overt physical ailments, and potentially neglect psychological stressors. A judgement bias task may allow researchers to evaluate an animal's subjective mental or affective state to provide a more comprehensive welfare assessment. Thus, group housed sows were trained to a spatial differentiation task to evaluate their ability to be assessed for individual judgement bias. A total of 45 sows were trained to the task across two replicates, with 24 successfully meeting the learning criteria required to be tested for a judgement bias. In the first replicate, 60% of sows displayed positive bias while 40% displayed negative biases. In the second replicate, 52% of sows displayed positive biases while 33% of sows displayed negative biases. A linear mixed effects model revealed that feed rank affected the latency to approach the ambiguous stimulus (χ2 (1) = 9.47, p = 0.002) with more dominant animals being more likely to exhibit a positive bias. Given that all sows in the present study were group housed, as well as fed and managed similarly, these findings highlight the complexities underlying judgement bias outcomes.

Ontogeny of behavioral traits in commercial sows.

As the number of gestating sows reared in group housing increases, a better understanding of behavioral traits needed to negotiate these more complex social interactions promises to increase animal welfare and productivity. However, little is known about different behavioral strategies or coping styles in sows, and even less is understood about their ontogeny. To study the development of coping styles in adult gestating sows, 36 sows from the same sire line and same commercial maternal genetics were followed from birth through their second parity. Each animal was observed in a battery of stress-related behavioral tests at 5 weeks, and 3 months of age as well as 24 h postpartum as a parity 1 sow, and during introduction to subsequent gestation period in group housing. The tests at different ages included response to handling, open field exploration, human interaction, litter handling and social interactions with conspecifics. Many of the observed behaviors were correlated during the same period of the animal's life and provided the motivation for a principal component analysis by age. Using principal component analysis, multiple traits were determined at each age point; at 5 weeks old: active, non-exploratory and cautious explained 82.5% of the variance; at 3 months of age: active, non-exploratory and low fear of humans explained 87.7% of the variance; and as primiparous sows: active, aggressive/dominant and submissive explained 82.0% of the variance. Several individual juvenile behaviors were associated with adult behavioral traits. For instance, the response to handling at 5 weeks was significantly predictive (ß=0.4; P<0.05) of the aggressive/dominant trait of parity 1 sows. Taken together results presented here suggest that early behavioral responses of prepuberal gilts during specific instances of elevated environmental or social stress can predict future behavioral response as gestating sows.

Temporal stability of personality traits in group-housed gestating sows.

The movement of sows (Sus scrofa domesticus) out of individual gestation stalls and into group housing can introduce new sources of stress due to the enhanced environmental and social complexity. Some sows may have the behavioral capacity to adapt to these changes better than others. However, little is known about individual differences in behavioral responses, or personality traits, in gestating sows and how they impact the animal's ability to cope with group housing. The temporal consistency in the assessment of an animal's behavior is a prerequisite to the establishment of personality traits and was addressed at an interval of approximately five months during two consecutive gestation periods in the present study. Forty-six group-housed sows from a commercially available genetic line were assessed for aggressive and social behaviors at mixing into a group, reaction to human approach, ease of handling, exploration of an open field, and reaction to a novel object. Principal component analysis revealed the presence of three traits accounting for over 60% of the variance in behaviors: aggressive/dominant, avoidant of humans and active/exploratory. Individual component scores were significantly correlated between pregnancies demonstrating temporal stability of trait assessment. Significant relationships were found between aggressive/dominant component scores and individual feed rank at electronic sow feeding stations and skin lesion scores, as well as between avoidant of humans component scores and average number of stillbirths per litter. These findings provide evidence for the temporal stability of distinct behaviors contributing to personality traits within a group of genetically similar sows and demonstrate how these traits may be useful in identifying individuals likely to succeed in group housing.

Brain-computer interface targeting non-motor functions after spinal cord injury: a case report.

STUDY DESIGN: This is a case report. OBJECTIVES: The objective of this study was to report on a brain-computer interface (BCI) paradigm that is successfully used with an inpatient spinal cord injury patient. SETTING: This study was conducted in an inpatient rehabilitation hospital. METHODS: A 25-year-old man with a C5 burst fracture and subsequent tetraplegia (The American Spinal Injury Association) participated in this case study. He completed a brief battery of psychological, pain, cognitive and other screening measures at points before and after the BCI paradigm during his rehabilitation hospitalization. RESULTS: The paradigm was easily learned and well tolerated with no adverse effects. CONCLUSIONS: This case is reflective of the trends in our ongoing feasibility study evaluating BCI technology in the inpatient rehabilitation setting. Clinical implications and challenges of using this technology in a busy hospital unit are reviewed.

Cognitive effects of short-term use of raloxifene: a randomized clinical trial.

Two questions regarding findings from the Women's Health Initiative are (1) What is the effect of various hormonal regimens including selective estrogen receptor modulators? and (2) Is the negative effect on cognitive functioning related to the older age (65+ years) of the women? This study addresses these two questions in a short-term randomized trial of the effects of raloxifene versus alendronate on cognition. The study found only one significant interaction where the raloxifene and alendronate group changed differently across the two testing occasions. Hence, raloxifene does not have any impact, positive or negative, on short-term cognitive functioning when compared to alendronate.

Structure and function of the hair cell ribbon synapse.

Faithful information transfer at the hair cell afferent synapse requires synaptic transmission to be both reliable and temporally precise. The release of neurotransmitter must exhibit both rapid on and off kinetics to accurately follow acoustic stimuli with a periodicity of 1 ms or less. To ensure such remarkable temporal fidelity, the cochlear hair cell afferent synapse undoubtedly relies on unique cellular and molecular specializations. While the electron microscopy hallmark of the hair cell afferent synapse--the electron-dense synaptic ribbon or synaptic body--has been recognized for decades, dissection of the synapse's molecular make-up has only just begun. Recent cell physiology studies have added important insights into the synaptic mechanisms underlying fidelity and reliability of sound coding. The presence of the synaptic ribbon links afferent synapses of cochlear and vestibular hair cells to photoreceptors and bipolar neurons of the retina. This review focuses on major advances in understanding the hair cell afferent synapse molecular anatomy and function that have been achieved during the past years.

Dhea supplementation and cognition in postmenopausal women.

Previous work has suggested that DHEA supplementation may have adverse cognitive effects in elderly women. This article analyzed 24-h measurements of DHEA, DHEAS, and cortisol to determine if cognitive decrease with treatment is mediated by DHEA's impact on endogenous cortisol. It was found that DHEA administration increased cortisol at several hours during the day. In the treatment group, cortisol was positively associated with cognition at study completion. An increase in negative associations between DHEA(S) levels and cognition was found at completion. Increased cortisol does not explain the cognitive deficits associated with DHEA, suggesting a direct negative effect of exogenous DHEA on cognition.

Pregnancy history and cognition during and after pregnancy.

An increasing body of literature confirms anecdotal reports that cognitive changes occur during pregnancy. This article assessed whether prior pregnancy, which alters a woman's subsequent hormonal environment, is associated with a specific cognitive profile during and after pregnancy. Seven primigravids and nine multigravids were compared, equivalent for age and education. No differences between groups were found during pregnancy. After delivery, multigravids performed better than primigravids on verbal memory tasks. After controlling for mood, a significant difference in verbal memory remained. A neuroadaptive mechanism may develop after first pregnancy that increases the ability to recover from some cognitive deficits after later pregnancies.

Synaptic ribbon. Conveyor belt or safety belt?

The synaptic ribbon in neurons that release transmitter via graded potentials has been considered as a conveyor belt that actively moves vesicles toward their release sites. But evidence has accumulated to the contrary, and it now seems plausible that the ribbon serves instead as a safety belt to tether vesicles stably in mutual contact and thus facilitate multivesicular release by compound exocytosis.

Chick cochlear hair cell exocytosis mediated by dihydropyridine-sensitive calcium channels.

1. A semi-intact preparation of the chick basilar papilla was developed to study calcium-dependent neurotransmitter release by tall hair cells (avian equivalent of cochlear inner hair cells). 2. Tall hair cell depolarization resulted in changes in cell membrane capacitance (DeltaC(m)) that reflected cell surface area increases following synaptic vesicle exocytosis and provided a surrogate measure of neurotransmitter release. Both calcium current (I(Ca)) and DeltaC(m) were reversibly blocked by cobalt, and exhibited a similar bell-shaped dependency on voltage with a peak response around -10 mV. 3. Pharmacological agents selective for L-type calcium channels were employed to assess the role of this channel type in neurotransmitter exocytosis. Nimodipine, a dihydropyridine (DHP) antagonist, suppressed I(Ca) and blocked DeltaC(m). Conversely, the DHP agonist Bay K 8644 increased both I(Ca) and DeltaC(m) amplitude nearly 3-fold. These findings suggest that chick tall hair cell neurotransmitter release is mediated by calcium influx through L-type calcium channels.

Nutrient management practices among swine operations of various sizes.

OBJECTIVE: To determine feeding, cropping, and manure-handling practices of swine operations of various sizes. DESIGN: Producer survey. SAMPLE POPULATION: 85 sow units and 132 finish floors. PROCEDURE: Swine producers were surveyed by mail and during farm visits for information regarding herd characteristics and management practices, with emphasis on the 3 components of the nutrient cycle: cropping, feeding and nutrition, and manure handling. Farms were categorized by operation type as sow units or finish floors and, subsequently, stratified by size as small sow units (< 600 head), large sow units (> or = 600 head), small finish floors (< 2,000 head), and large finish floors (2 > or = 2,000 head). RESULTS: Large sow units and large finish floors were approximately twice as likely to use environmentally sound nutrient management practices as small sow units or small finish floors. These large operations were more likely to use progressive feeding practices, to be aware of their nutrient flows, and to be capable of using these nutrients properly. CONCLUSIONS AND CLINICAL RELEVANCE: There is a need for greater environmental awareness among all swine producers, especially among small producers. This provides a possible growth area for large-animal veterinary consultants. Economy of scale and increased governmental regulations allow large farms to use environmentally sound practices. Thus, large swine farms are not necessarily harmful to the environment.

Millisecond studies of calcium-dependent exocytosis in pituitary melanotrophs: comparison of the photolabile calcium chelators nitrophenyl-EGTA and DM-nitrophen.

DM-nitrophen (DMN) is a photolabile calcium chelator that has been used extensively to study calcium-triggered exocytosis. Nitrophenyl-EGTA (NPE) is a recently synthesized photolabile calcium chelator that, unlike DMN, selectively binds calcium over magnesium. Here, we compare NPE and DMN for their effectiveness in raising cytosolic calcium ([Ca]i) to trigger exocytosis. The whole cell patch clamp technique was used to monitor membrane capacitance (Cm) and to load both calcium indicator dye and photolabile chelators into rat pituitary melanotrophs prior to flash photolysis. In cells dialysed with DMN, a transient increase in [Ca]i was observed immediately after continuity between the patch pipette and the cell cytosol was achieved. This 'loading transient' reflects the release of calcium from DMN during the binding of intracellular magnesium. No such transient was seen with NPE, consistent with the negligible binding of magnesium to this chelator. Following flash photolysis of DMN or NPE, [Ca]i increased, triggering both a rapid exocytic burst and slower sustained phases of exocytosis. When flashes of the same intensity were compared, the photolysis of NPE resulted in smaller increases in [Ca]i and slower exocytic bursts than that of DMN. These findings are in accordance with the properties of the two compounds [Ellis-Davies G.C.R., Kaplan J.H. Nitrophenyl-EGTA, a photolabile chelator that selectively binds Ca2+ with high affinity and releases it rapidly upon photolysis. Proc Natl Acad Sci USA 1994; 91: 187-191] and the calcium dependency of the exocytic burst [Thomas P., Wong J.G., Lee A.K., Almers W. A low affinity Ca2+ receptor controls the final steps in peptide secretion from pituitary melanotrophs. Neuron 1993; 11: 93-104]. Although NPE is somewhat less effective than DMN in raising [Ca]i, this chelator promises to be a useful and interesting tool for the time-resolved study of calcium-dependent exocytosis in the presence of physiological concentrations of magnesium.

Financial evaluation of vaccination and testing alternatives for control of parvovirus-induced reproductive failure in swine.

OBJECTIVE: To identify the preferable testing and vaccination strategy for control of porcine parvovirus (PPV) during a 6-month period. DESIGN: Decision-tree analysis and computer simulations. SAMPLE POPULATION: Computer modeling of 300-sow farrow-to-finish herd. PROCEDURE: Serologic testing of 30 females to estimate herd PPV prevalence versus not testing any females was the initial decision alternative. On the basis of serologic test results, herds were classified into 1 of 3 PPV-risk categories: low (> or = 80% seropositive females), moderate (40 to < 80% seropositive females), or high (< 40% seropositive females). Vaccinating all females, only gilts, or not vaccinating was the second decision alternative. RESULTS: For initial model assumptions (test sensitivity and specificity = 0.95; test cost = $5/female; vaccination cost = $0.30/dose; vaccination efficacy = 0.95; and foregone gross margin = $10.85/pig), vaccination of all females (with or without serologic testing) was preferable, but the financially preferable option was to omit serologic testing. Most profitable vaccination option varied with foregone gross margin, vaccination cost, and efficacy. For herds in which all sows were known to be immune, vaccinating only gilts was financially preferable, and serologic testing was not warranted. Variation is expected monetary losses was less in vaccination options than with nonvaccination. CLINICAL IMPLICATIONS: For most herds in the United States, serologic screening for PPV prior to selection of a vaccination program is unlikely to be cost-effective, because vaccination is inexpensive ($0.30/dose) and effective (95%). At current profit margins ($10.85/pig), vaccination of all females has the least-risk and is the preferred option.

Docked granules, the exocytic burst, and the need for ATP hydrolysis in endocrine cells.

Ca(2+)-triggered exocytosis was studied in single rat melanotrophs and bovine chromaffin cells by capacitance measurements. Sustained exocytosis required MgATP, but even in the absence of MgATP, Ca2+ could trigger exocytosis of 2700 granules in a typical melanotroph and of 840 granules in a chromaffin cell. Granules undergoing ATP-independent exocytosis were similar in number to those appearing docked to the plasmalemma in quickly frozen unfixed sections (3300 in a melanotroph and 830 in a chromaffin cell). Most exocytosis required tens of seconds, but a small pool of granules was released in tens of milliseconds. Evidently, only a small subset of docked granules is rapidly releasable. We suggest that, temporally, the last ATP-dependent step in exocytosis is closely associated with docking and that docked granules reach fusion competence only after subsequent steps.

Calcium-triggered exocytosis and endocytosis in an isolated presynaptic cell: capacitance measurements in saccular hair cells.

Depolarization of isolated frog saccular hair cells caused Ca(2+)-dependent increases in membrane capacitance that we interpret as the fusion of synaptic vesicles with the plasma membrane. During a maintained depolarization to -10 mV, the capacitance increased at a rate corresponding to the fusion of approximately 500 vesicles per second at each active zone. Release continued at this high rate for up to 2 s, long enough to exhaust > 5 times the number of vesicles initially in close apposition to the plasma membrane at active zones. We therefore propose that hair cells are specialized for rapid replenishment of vesicles at release sites. Upon repolarization to -70 mV, the capacitance returned exponentially (time constant, approximately 14 s) to near the prestimulus level in perforated-patch recordings, but not in whole-cell recordings, suggesting that a mobile intracellular factor is required for membrane retrieval.

Regulation of Ca2+ current in frog ventricular cardiomyocytes by guanosine 5'-triphosphate analogues and isoproterenol.

Calcium currents (ICa) were measured in frog ventricular myocytes using the whole-cell patch clamp technique and a perfused pipette. To gain insight into the role of G proteins in the regulation of ICa in intact cells, the effect of internal perfusion with hydrolysis-resistant GTP analogues, guanylyl 5'-imidodiphosphate (GppNHp) or guanosine 5'-thiotriphosphate (GTP gamma S), on ICa stimulated by isoproterenol (Iso) or forskolin (Forsk) was examined. Significant differences were observed between the effects of the two GTP analogues. Internal perfusion of GppNHp resulted in a near-complete (approximately 80%) and irreversible inhibition of Iso-stimulated ICa. In contrast, internal perfusion with GTP gamma S resulted in only a partial (approximately 40%) inhibition of Iso- or Forsk-stimulated ICa. The fraction of the current not inhibited by GTP gamma S remained persistently elevated after the washout of Iso but declined to basal levels upon washout of Forsk. Excess internal GTP or GppNHp did not reduce the persistent ICa. Internal adenosine 5'-thiotriphosphate (ATP gamma S) mimicked the GTP gamma S-induced, persistent ICa. GppNHp sometimes induced a persistent ICa, but only if GppNHp was present at high concentration before Iso exposure. Inhibitors of protein kinase A inhibited both the GTP gamma S- and ATP gamma S-induced, persistent ICa. We conclude that: (a) GTP gamma S is less effective than GppNHp in inhibiting adenylyl cyclase (AC) via the inhibitory G protein, Gi; and (b) the persistent ICa results from a long-lived Gs-GTP gamma S complex that can activate AC in the absence of Iso. These results suggest that different hydrolysis-resistant nucleotide analogues may behave differently in activating G proteins and imply that the efficacy of G protein-effector molecule interactions can depend on the GTP analogue with which the G protein is activated.

Aminoglycoside antibiotics block voltage-dependent calcium channels in intact vertebrate nerve terminals.

Intrinsic and extrinsic optical signals recorded from the intact nerve terminals of vertebrate neurohypophyses were used to investigate the anatomical site and physiological mechanism of the antagonistic effects of aminoglycoside antibiotics on neurotransmission. Aminoglycoside antibiotics blocked the intrinsic light scattering signal closely associated with neurosecretion in the mouse neurohypophysis in a concentration-dependent manner with an IC50 of approximately 60 microM and the block was relieved by increasing [Ca2+]o. The rank order potency of different aminoglycoside antibiotics for blocking neurosecretion in this preparation was determined to be: neomycin greater than gentamicin = kanamycin greater than streptomycin. Optical recordings of rapid changes in membrane potential using voltage-sensitive dyes revealed that aminoglycoside antibiotics decreased the Ca(2+)-dependent after-hyperpolarization of the normal action potential and both the magnitude and after-hyperpolarization of the regenerative Ca2+ spike. The after-hyperpolarization results from a Ca-activated potassium conductance whose block by aminoglycoside antibiotics was also reversed by increased [Ca2+]o. These studies demonstrate that the capacity of aminoglycoside antibiotics to antagonize neurotransmission can be attributed to the block of Ca channels in the nerve terminal.

Long-term optical recording of patterns of electrical activity in ensembles of cultured Aplysia neurons.

1. Left upper quadrant (LUQ) cells isolated from the abdominal ganglion of Aplysia were maintained in culture to study how the cellular and synaptic properties of individual neurons contribute to the generation of patterns of electrical activity by neuronal ensembles. 2. Conventional microelectrodes were used to examine the spiking characteristics of individually cultured LUQ cells in vitro and to characterize their synaptic interactions. 3. In vitro, in contrast to in situ, LUQ neurons innervate other LUQ neurons. Intracellular recordings from pairs of LUQ cells showed that the prevalent type of postsynaptic potential was purely inhibitory. The other type of response was a dual-action postsynaptic potential, with inhibition followed by a delayed, slow excitation. 4. We established a set of criteria for the use of multiple-site optical recording techniques, in combination with impermeant probes of membrane potential, to observe the patterns of electrical activity generated by ensembles of co-cultured LUQ cells. 5. The spiking activity of individual cells within the neuronal ensembles was detected by means of the change in optical absorption of cells that were vitally stained with the dye RH155. The change in absorption was typically delta A congruent to 4 X 10(-4) per spike. We achieved a signal-to-noise (peak-to-peak) ratio of approximately 10 for a 50 X 50-microns photodetector field and an incident intensity of approximately 10 mW/cm2, close to the theoretical limit. 6. These conditions permitted, for the first time, continuous optical recording from cultured neurons for periods of up to 3 h with no discernible photodynamic damage or photobleaching. This long-term optical recording permitted examination of the different patterns of electrical activity generated by individual neuronal ensembles under several different experimental conditions. 7. An elaborate tracery of regenerated neurites present in these cultures resulted in individual photodetectors recording simultaneously the activity of multiple neurons. We reconstructed the temporal firing patterns for individual neurons within ensembles even with all the neurons active simultaneously and determined the functional connections in the ensemble by analyzing the temporal relationships between firing patterns of individual neurons. Excitatory as well as inhibitory functional interactions could be observed within the neuronal ensemble, the latter after the tonic activity of the neurons was increased by reducing the extracellular [Mg2+]. 8. Examination of the optical data from ensembles constructed from identified cells having characteristic physiological responses allowed us to address the question of how cellular and synaptic properties affect the patterns of electrical activity generated by neuronal ensembles.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of Ca2+ current in frog ventricular cardiomyocytes by 5'-guanylylimidodiphosphate and acetylcholine.

1. Calcium currents (ICa) were measured in frog ventricular myocytes using the whole-cell patch clamp technique and a perfused pipette. The effect of internal perfusion with the hydrolysis-resistant GTP analogue, GppNHp (5'guanylylimidodiphosphate), on basal ICa and ICa stimulated with forskolin or isoprenaline was examined to gain insight into the role of G proteins in ICa regulation. 2. Without added guanine nucleotides, isoprenaline stimulated ICa approximately 14-fold with an EC50 of 0.09 microM. Forskolin stimulated ICa approximately 10-fold with an EC50 of 0.30 microM. 3. Internal 30 microM-GppNHp produced an approximately 80% decrease in ICa elevated by 0.3 microM-isoprenaline or 3 microM-forskolin. The inhibition of isoprenaline stimulation was due to a decrease in the maximal stimulation from approximately 14-fold to approximately 14-fold without a significant change in the EC50. In contrast, the reduction in forskolin stimulation was due to a 22-fold increase in the EC50 to 11.4 microM, with little change in maximal stimulation. 4. The inhibition of stimulated ICa by GppNHp is likely to be mediated by a G protein, because the effects of GppNHp are irreversible, and are blocked by excess GTP. ICa is affected similarly by GppNHp and by ACh. This suggests that GppNHp activates the same G protein that is normally activated by ACh, but activation by GppNHp occurs in the absence of agonist occupation of the muscarinic receptor. 5. The increase in the EC50 for forskolin produced by internal GppNHp was reversed by exposure to isoprenaline, which itself did not affect ICa amplitude. On average, exposure to isoprenaline in the presence of GppNHp caused an irreversible 81-fold decrease in the EC50 for forskolin to 0.14 microM. Stimulation of ICa by forskolin after internal GppNHp and exposure to isoprenaline was completely blocked by the protein kinase A inhibitor PKI(5-22). 6. These effects do not involve the phospholipase C system, because they are not mimicked by phorbol esters or internal inositol 1,4,5-trisphosphate (IP3) and are not blocked by bromophenacyl bromide or neomycin. 7. Direct effects of G proteins on ICa were not evident, because internal perfusion with PKI(5-22) completely inhibited isoprenaline- or forskolin-stimulated increases in ICa, and neither ACh nor internal GppNHp (30-500 microM) affected basal ICa or ICa elevated by internally perfused cyclic AMP. 8. These results suggest that the predominant site of action of the inhibitory G protein activated by either GppNHp or ACh is adenylyl cyclase. Furthermore, the internally perfused frog cardiomyocytes may provide a useful approach for probing the detailed interactions of G proteins, forskolin, and adenylyl cyclase in an intact cell.