Quantifying the frequency and volume of urine deposition by grazing sheep using tri-axial accelerometers.

Urine patches deposited in pasture by grazing animals are sites of reactive nitrogen (N) loss to the environment due to high concentrations of N exceeding pasture uptake requirements. In order to upscale N losses from the urine patch, several urination parameters are required, including where, when and how often urination events occur as well as the volume and chemical composition. There are limited data available in this respect, especially for sheep. Here, we seek to address this knowledge gap by using non-invasive sensor-based technology (accelerometers) on ewes grazing in situ, using a Boolean algorithm to detect urination events in the accelerometer signal. We conducted an initial study with penned Welsh Mountain ewes (n = 5), with accelerometers attached to the hind, to derive urine flow rate and to determine whether urine volume could be estimated from ewe squat time. Then accelerometers attached to the hind of Welsh Mountain ewes (n = 30 at each site) were used to investigate the frequency of sheep urination events (n = 35 946) whilst grazing two extensively managed upland pastures (semi-improved and unimproved) across two seasons (spring and autumn) at each site (35-40 days each). Sheep urinated at a frequency of 10.2 ± 0.2 and 8.1 ± 0.3 times per day in the spring and autumn, respectively, while grazing the semi-improved pasture. Urination frequency was greater (19.0 ± 0.4 and 15.3 ± 0.3 times per day in the spring and autumn, respectively) in the unimproved pasture. Ewe squat duration could be reliably used to predict the volume of urine deposited per event and was thus used to estimate mean daily urine production volumes. Sheep urinated at a rate of 16.6 mL/s and, across the entire dataset, sheep squatted for an average of 9.62 ± 0.03 s per squatting event, producing an estimated average individual urine event volume of 159 ± 1 mL (n = 35 946 events), ranging between 17 and 745 mL (for squat durations of 1 to 45 s). The estimated mean daily urine volume was 2.15 ± 0.04 L (n = 2 669 days) across the entire dataset. The data will be useful for modelling studies estimating N losses (e.g. ammonia (NH3) volatilisation, nitrous oxide (N2O) emission via nitrification and denitrification and nitrate (NO3-) leaching) from urine patches.

Motor Conflict: Revealing Involuntary Conditioned Motor Preparation Using Transcranial Magnetic Stimulation.

Preparing actions to achieve goals, overriding habitual responses, and substituting actions that are no longer relevant are aspects of motor control often assumed to be driven by deliberate top-down processes. In the present study, we investigated whether motor control could come under involuntary control of environmental cues that have been associated with specific actions in the past. We used transcranial magnetic stimulation (TMS) to probe corticospinal excitability as an index of motor preparation, while participants performed a Go/No-Go task (i.e., an action outcome or no action outcome task) and rated what trial was expected to appear next (Go or No-Go). We found that corticospinal excitability during a warning cue for the upcoming trial closely matched recent experience (i.e., cue-outcome pairings), despite conflicting with what participants expected would appear. The results reveal that in an action-outcome task, neurophysiological indices of motor preparation show changes that are consistent with participants learning to associate a preparatory warning cue with a specific action, and are not consistent with the action that participants explicitly anticipate making. This dissociation with conscious expectancy ratings reveals that conditioned responding and motor preparation can operate independently of conscious expectancies about having to act.

The topography of tactile working memory.

To investigate the contribution of topographically organized brain areas to tactile working memory, we asked human subjects to compare the frequency of two vibrations presented to the same fingertip or to different fingertips. The vibrations ranged from 14 to 24 Hz and were separated by a retention interval of variable length. For intervals <1 sec, subjects were accurate when both vibrations were delivered to the same fingertip but were less accurate when the two vibrations were delivered to different fingertips. For 1 or 2 sec intervals, subjects performed equally well when comparing vibrations delivered either to the same finger or to corresponding fingers on opposite hands, but they performed poorly when the vibrations were delivered to distant fingers on either hand. These results suggest that working memory resides within a topographic framework. As a further test, we performed an experiment in which the two comparison vibrations were presented to the same fingertip but an interference vibration was presented during the retention interval. The interpolated vibration disrupted accuracy most when delivered to the same finger as the comparison vibrations and had progressively less effect when delivered to more distant fingers. We conclude that topographically organized regions of somatosensory cortex contribute to tactile working memory, possibly by holding the memory trace across the retention interval. One stimulus can be accurately compared with the memory of a previous stimulus if they engage overlapping representations, but activation of the common cortical territory by an interpolated stimulus can disrupt the memory trace.

Object orientation agnosia: a failure to find the axis?

A dissociation between the ability to recognize misoriented objects and to determine their orientation has been reported in a small number of patients with vascular lesions. In this article, we describe a 57-year-old man with probable Alzheimer' s disease who shows the same dissociation. Neuroimaging findings indicated marked hypometabolism in the posterior cortical regions, particularly the postero-superior parietal lobes. Clinically, the patient had good object recognition accompanied by severely impaired spatial abilities. The experimental investigations comprised a variety of tasks in which he identified misoriented objects, evaluated the orientation of single objects, or discriminated the orientation of simultaneously presented items. Results revealed that his object recognition was independent of orientation and was largely mediated by salient features. With respect to orientation judgements, the patient displayed a profound inability to judge the orientation of nonupright objects, but remarkably intact (though largely implicit) knowledge of the upright orientation. Strikingly, his orientation judgements were also more accurate for upside-down objects than for other orientations (i.e., 90 degrees ). We interpret these results as evidence that judgements about object orientation are facilitated when the orientation of the principal axis of the object matches that of an internal representation. We propose that the inability to determine other orientations may be due to the failure of an "axis-finding" mechanism implemented in the posterior parietal lobes, that translates between object-centered and eye-centered coordinates appropriate for guiding visual scanning.

Effect of ABO blood group mismatching on corneal epithelial cells: an in vitro study.

AIM: To determine, in vitro, the effects of blood group ABO mismatching on corneal epithelial cells. METHODS: Corneal epithelial cell cultures were established from 32 human cadaver donor eyes. Epithelial cells (100 microl of 4 x 10(2) cells per microl) were incubated for 4 hours with antibodies against blood group antigens A, B, and AB, with and without complement. Cell lysis was assayed by a chemiluminescent assay using Cytolite reagent. Live cells, remaining after incubation, were counted in a scintillation counter. The blood group of the donors was determined retrospectively, in a blinded manner. RESULTS: Retrospective tracing of donor blood groups was possible for 20 donors. In all cases the blood group corresponded with that suggested by the cell lysis assay. Significant cell lysis was observed when known A group cells were incubated with anti-A and anti-AB antibody, B group cells were incubated with anti-B and AB antibody, and AB group cells were incubated with anti-AB antibody. Lysis occurred only in the presence of complement. No lysis of O group cells was observed with any of the antibodies. In all cases, lysis was observed only with neat (serum) antibody concentrations. CONCLUSIONS: Blood group ABO mismatching results in significant lysis of corneal epithelial cells. The antibody concentration required for lysis equals that found in serum. Such levels of antibody are unlikely to be achieved in tears and/or aqueous. This may offer an explanation for the conflicting reports of the studies on the effect of blood group matching on corneal grafts. The variability in the outcome may reflect the levels of antibodies gaining access to the corneal cells and not the mismatching alone.

The effects of mesial temporal and cerebellar hypometabolism on learning and memory.

The effects of mesial temporal (MT) and cerebellar hypometabolism were studied using measures of verbal, visual and motor skill learning. Twelve patients with refractory temporal lobe epilepsy who showed asymmetrical mesial temporal lobe hypometabolism on [18F] fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) were given tests involving 4 consecutive learning trials and a 30-min delayed recall trial. Delayed recognition was also assessed for the words and designs, and skill transfer was evaluated for mirror drawing. Compared to 9 normal control participants, patients with more marked MT hypometabolism on the left had impaired delayed recall of words and patients with more marked MT hypometabolism on the right showed impaired learning of novel designs, but normal retention over delay. Patients were not impaired in their mirror-drawing performance. The findings for MT hypometabolism correspond well to those obtained in other studies where patients have been classified on the basis of side of hippocampal atrophy or temporal lobe excision.

The topography of tactile learning in humans.

The spatial distribution of learned information within a sensory system can shed light on the brain mechanisms of sensory-perceptual learning. It has been argued that tactile memories are stored within a somatotopic framework in monkeys and rats but within a widely distributed network in humans. We have performed experiments to reexamine the spread of tactile learning across the fingertips. In all experiments, subjects were trained to use one fingertip to discriminate between two stimuli. Experiment 1 required identification of vibration frequency, experiment 2 punctate pressure, and experiment 3 surface roughness. After learning to identify the stimuli reliably, subjects were tested with the trained fingertip, its first and second neighbors on the same hand, and the three corresponding fingertips on the opposite hand. As expected, for all stimulus types, subjects showed retention of learning with the trained fingertip. However, the transfer beyond the trained fingertip varied according to the stimulus type. For vibration, learning did not transfer to other fingertips. For both pressure and roughness stimuli, there was limited transfer, dictated by topographic distance; subjects performed well with the first neighbor of the trained finger and with the finger symmetrically opposite the trained one. These results indicate that tactile learning is organized within a somatotopic framework, reconciling the findings in humans with those in other species. The differential distribution of tactile memory according to stimulus type suggests that the information is stored in stimulus-specific somatosensory cortical fields, each characterized by a unique receptive field organization, feature selectivity, and callosal connectivity.

Regulatory and ethical issues with dietary supplements.

Dietary supplements are commonly used, and many are effective or hold promise for treating various conditions. However, they do not require Food and Drug Administration (FDA) approval. Impurities and adulterants have been found in the products, mostly due to the lack of requirements for good manufacturing practices. In addition, as no standardization is required, the active ingredient may be absent or highly variable among manufacturers. The FDA published its 10-year plan for dietary supplements that addresses safety, labeling, boundaries, enforcement, research, and outreach. This endeavor, if put into place, will be instrumental in providing consumers with more confidence in the safety, composition, and labeling of dietary supplements.

White paper on herbal products. American College of Clinical Pharmacy.

Individuals increasingly are taking a more active role in their health care, and herbal products have emerged as a common choice among self-care therapies. Pharmacists are active participants in the care of patients who are taking herbal products. Currently, most pharmacists are not educated adequately about herbal products and other types of alternative medicine. Furthermore, good information about many of these products is not available. These combined factors present a challenge for pharmacists as they seek to provide optimal care and counseling to patients who use herbs or supplements. We recommend the following actions to place pharmacists in better positions as effective agents protecting public safety: Regulations should be implemented at a federal level to require basic levels of standardization and quality control in the manufacture of herbal products. Indexing terms in medical bibliographic systems should be expanded to target herbal products. Funding should be increased for scientific research evaluating herbal products. Pharmacy schools should include a competency statement in their curricula regarding herbal medicines. Continuing education in herbal products should be available and encouraged for all pharmacists. Pharmacists should approach the use of all therapeutic interventions with scientific rigor, whether they are traditional or complementary in nature. Patients will benefit as more information is known and widely disseminated. By actively embracing the responsibility for counseling individuals on the appropriate use of herbal products, pharmacists will become a recognized source of expert information in this rapidly growing area, yielding important improvements in the quality of care.

Selective right parietal lobe activation during mental rotation: a parametric PET study.

Regional cerebral blood flow (rCBF) was measured with PET in seven healthy subjects while they carried out a mental rotation task in which they decided whether alphanumeric characters presented in different orientations were in their canonical form or mirror-reversed. Consistent with previous findings, subjects took proportionally longer to respond as characters were rotated further from the upright, indicating that they were mentally rotating the characters to the upright position before making a decision. We used a parametric design in which we varied the mental rotation demands in an incremental fashion while keeping all other aspects of the task constant. In four different scanning conditions, 10, 40, 70 or 100% of the stimuli presented during the scan required mental rotation while the rest were upright. The statistical parametric mapping technique was used to identify areas where changes in rCBF were correlated with the rotational demands of the task. Significant activation was found in only one area located in the right posterior parietal lobe, centred on the intraparietal sulcus (Brodmann area 7). The experimental literature on monkeys and humans suggests that this area is involved in a variety of spatial transformations. Our results contribute evidence that such transformations are recruited during mental rotation and add to a body of evidence which suggests that the right posterior parietal lobe is important for carrying out visuospatial transformations.

Homocysteine and cardiovascular disease.

After a thorough review of the available literature, it appears that hyperhomocysteinemia is an independent risk factor for CHD. Furthermore, folic acid has been shown to reduce homocysteine concentration. Nevertheless, CHD is a multifactorial process, and many risk factors play a role in its pathogenesis. Several unanswered questions remain regarding the role of folic acid supplementation in hyperhomocysteinemia (Table 3). The absolute homocysteine concentration at which cardiovascular risk increases is not certain, and the magnitude of homocysteine-lowering needed to prevent events is unknown. Consequently, the number needed to treat cannot be calculated for folic acid supplements. Based on these data, the populations in whom to evaluate a homocysteine concentration have yet to be described. Because the POEMs are not yet available, it is unknown whether supplemental folic acid to lower homocysteine concentration will reduce CHD morbidity and mortality. It will take several years before any randomized, controlled trials are done, and primary prevention trials will need to be of very long duration to show any change in outcomes. Widespread use of folic acid supplementation has been recommended, however, and the need for clinical outcomes might be precluded. Even in the absence of outcome data, the potential benefits of using folic acid appear to outweigh any risks. A diet high in folic acid should be encouraged in everyone (Table 4). The FDA-mandated folic acid fortification of enriched grain products is most likely insufficient to lower homocysteine concentrations meaningfully, and a daily multivitamin that contains 400 microg of folic acid should be considered for patients who have documented CHD (especially when other risk factors are absent or in patients with premature atherosclerosis) and men and women who have cardiovascular risk factors, in addition to women of childbearing potential. Folic acid supplementation in the form of a multivitamin once daily is safe and inexpensive and might prevent the development and progression of CHD.

Cardiac sarcoidosis: a new approach to treatment.

Cardiac sarcoid is a disease of young adults. Arrhythmias or sudden death may be the first manifestation of cardiac sarcoidosis. Consideration for cardiac sarcoid should be given to all young patients with arrhythmias, heart failure, or episodes of sudden death. Surgical intervention may be warranted in patients with symptomatic cardiac sarcoid because of poor response to current medical therapy.

The M1 Kegworth aircraft disaster: experience in three hospital blood transfusion laboratories and the regional transfusion centre.

Eighty-eight survivors of an aircraft accident on the M1 motorway were taken to three major hospitals, two of which were teaching hospitals, in the immediate vicinity. We describe the effects of this on the three blood transfusion and haematology laboratories concerned and on the regional transfusion centre, describe how the work was processed, and list the lessons learnt.

An additional example of autoanti-M.

A sixth example of a potent autoanti-M is described in a nongravida, nontransfused Caucasian woman. The anti-M was still present after a period of 12 months without any apparent cause.