Unambiguous identification of Ancylostoma caninum and Uncinaria stenocephala in Australian and New Zealand dogs from faecal samples.

Hookworms (Ancylostomatidae) are well-known parasites in dogs due to their health impacts and zoonotic potential. While faecal analysis is the traditional method for detection, improvements in husbandry and deworming have decreased their prevalence in urban owned dogs. Drug resistance in Ancylostoma caninum is becoming a discussion point in small animal practices across the region. This study aimed to identify hookworm species present in Australian and New Zealand dogs using molecular techniques. The ITS-2 and isotype-1 ß-tubulin assays were used to identify and quantify hookworm species. Results showed absence of coinfection in Australian samples from Greater Sydney region belonging either to A. caninum or Uncinaria stenocephala, while New Zealand samples were a mixture of A. caninum and U. stenocephala. The amplified isotype-1 ß-tubulin sequences exhibited susceptibility to benzimidazole drugs. Rare mutations were identified in A. caninum and U. stenocephala sequences, representing a small percentage of reads. This study highlights the importance of molecular techniques in accurately identifying and quantifying hookworm species in dog populations.

Abrupt CO2 release to the atmosphere under glacial and early interglacial climate conditions.

Pulse-like carbon dioxide release to the atmosphere on centennial time scales has only been identified for the most recent glacial and deglacial periods and is thought to be absent during warmer climate conditions. Here, we present a high-resolution carbon dioxide record from 330,000 to 450,000 years before present, revealing pronounced carbon dioxide jumps (CDJ) under cold and warm climate conditions. CDJ come in two varieties that we attribute to invigoration or weakening of the Atlantic meridional overturning circulation (AMOC) and associated northward and southward shifts of the intertropical convergence zone, respectively. We find that CDJ are pervasive features of the carbon cycle that can occur during interglacial climate conditions if land ice masses are sufficiently extended to be able to disturb the AMOC by freshwater input.

Coronary plaque volume and predictors for fast plaque progression assessed by serial coronary CT angiography-A single-center observational study.

PURPOSE: The rationale of this study was to identify patients with fast progression of coronary plaque volume PV and characterize changes in PV and plaque components over time. METHOD: Total PV (TPV) was measured in 350 patients undergoing serial coronary computed tomography angiography (median scan interval 3.6 years) using semi-automated software. Plaque morphology was assessed based on attenuation values and stratified into calcified, fibrous, fibrous-fatty and low-attenuation PV for volumetric measurements. Every plaque was additionally classified as either calcified, partially calcified or non-calcified. RESULTS: In total, 812 and 955 plaques were detected in the first and second scan. Mean TPV increase was 20 % on a per-patient base (51.3 mm³ [interquartile range (IQR): 14.4, 126.7] vs. 61.6 mm³ [IQR: 16.7, 170.0]). TPV increase was driven by calcified PV (first scan: 7.6 mm³ [IQR: 0.2, 33.6] vs. second scan: 16.6 mm³ [IQR: 1.8, 62.1], p < 0.01). Forty-two patients showed fast progression of TPV, defined as >1.3 mm3 increase of TPV per month. Male sex (odds ratio 3.1, p = 0.02) and typical angina (odds ratio 3.95, p = 0.03) were identified as risk factors for fast TPV progression, while high-density lipoprotein cholesterol had a protective effect (odds ratio per 10 mg/dl increase of HDL cholesterol: 0.72, p < 0.01). Progression to >50 % stenosis at follow-up was observed in 34 of 327 (10.4 %) calcified plaques, in 13 of 401 (3.2 %) partially calcified plaques and 2 of 221 (0.9 %) non-calcified plaques (p < 0.01). CONCLUSION: Fast plaque progression was observed in male patients and patients with typical angina. High HDL cholesterol showed a protective effect.

Effects of a CACNA1C genotype on attention networks in healthy individuals.

BACKGROUND: Recent genetic studies found the A allele of the variant rs1006737 in the alpha 1C subunit of the L-type voltage-gated calcium channel (CACNA1C) gene to be over-represented in patients with psychosis, including schizophrenia, bipolar disorder and major depressive disorder. In these disorders, attention deficits are among the main cognitive symptoms and have been related to altered neural activity in cerebral attention networks. The particular effect of CACNA1C on neural function, such as attention networks, remains to be elucidated. METHOD: The current event-related functional magnetic resonance imaging (fMRI) study investigated the effect of the CACNA1C gene on brain activity in 80 subjects while performing a scanner-adapted version of the Attention Network Test (ANT). Three domains of attention were probed simultaneously: alerting, orienting and executive control of attention. RESULTS: Risk allele carriers showed impaired performance in alerting and orienting in addition to reduced neural activity in the right inferior parietal lobule [Brodmann area (BA) 40] during orienting and in the medial frontal gyrus (BA 8) during executive control of attention. These areas belong to networks that have been related to impaired orienting and executive control mechanisms in neuropsychiatric disorders. CONCLUSIONS: Our results suggest that CACNA1C plays a role in the development of specific attention deficits in psychiatric disorders by modulation of neural attention networks.

Genetic variation in schizophrenia-risk-gene dysbindin 1 modulates brain activation in anterior cingulate cortex and right temporal gyrus during language production in healthy individuals.

Genetic variation in dysbindin 1 (DTNBP1) gene region tagged by SNP rs1018381 exhibits a linkage with cognitive deficits in patients with schizophrenia and healthy subjects. Language production deficits are core features of schizophrenia with more impairment in semantic than lexical verbal fluency tasks. We investigated the link between brain activation and DTNBP1 SNP rs1018381 during semantic verbal fluency task in a German healthy population. 46 healthy subjects genotyped for SNP rs1018381 status were divided in heterozygous risk-allele carriers (T/C) and homozygous non-carriers (C/C). Neural correlates of semantic verbal fluency were investigated with functional magnetic resonance imaging (fMRI). Stronger right hemispherical brain activation in anterior cingulate gyrus (BA 24), superior (BA 22, 38) and middle (BA 21) temporal gyrus was observed in the carriers compared to non-carriers. Brain activations occurred in the absence of task performance differences. No significant correlations were found between personality traits and brain activation differences. The results point to an influence of genetic variation in DTNBP1 gene region tagged by SNP rs1018381 on neural correlates of language production. Carriers may exhibit higher processing efforts to reach the same behavioural performance as non-carriers as reflected in activation of schizophrenia-related regions.

fMRI reveals cognitive and emotional processing in a long-term comatose patient.

We report on a 41-year old woman with prolonged comatose unresponsiveness following traumatic head injury. Structural MRI showed bilateral midbrain damage and ventriculomegalia. Functional MRI revealed robust cortical responses to visual, auditory and tactile stimulation. Speech stimuli moreover consistently elicited activation in Broca's and Wernicke's areas. Familiar speakers and direct addressing evoked significantly stronger amygdala activation than unfamiliar speakers and neutral phrases. This study hence demonstrates the potential of functional neuroimaging in the investigation of residual higher cortical functions in unresponsive comatose patients.

Fast quantitative mapping of absolute water content with full brain coverage.

Quantitative mapping of water content, especially in the human brain, has the potential to provide important information for the study and diagnosis of diseases associated with a focal or global change in tissue water homeostasis. In the current work, an imaging method for the precise and accurate quantification of tissue water content is presented. The method allows the acquisition of water content maps with voxel dimensions of 1x1x2 mm(3) and full brain coverage in less than 10 min on a standard clinical 1.5 T scanner. The precision was optimised for human brain imaging and possible sources of systematic error were carefully investigated, demonstrating the ability of the method to quantify water content with high accuracy and precision. The approach was validated in phantom experiments and quantitative cerebral water content maps of a group of 10 healthy volunteers were obtained.

Dust-climate couplings over the past 800,000 years from the EPICA Dome C ice core.

Dust can affect the radiative balance of the atmosphere by absorbing or reflecting incoming solar radiation; it can also be a source of micronutrients, such as iron, to the ocean. It has been suggested that production, transport and deposition of dust is influenced by climatic changes on glacial-interglacial timescales. Here we present a high-resolution record of aeolian dust from the EPICA Dome C ice core in East Antarctica, which provides an undisturbed climate sequence over the past eight climatic cycles. We find that there is a significant correlation between dust flux and temperature records during glacial periods that is absent during interglacial periods. Our data suggest that dust flux is increasingly correlated with Antarctic temperature as the climate becomes colder. We interpret this as progressive coupling of the climates of Antarctic and lower latitudes. Limited changes in glacial-interglacial atmospheric transport time suggest that the sources and lifetime of dust are the main factors controlling the high glacial dust input. We propose that the observed approximately 25-fold increase in glacial dust flux over all eight glacial periods can be attributed to a strengthening of South American dust sources, together with a longer lifetime for atmospheric dust particles in the upper troposphere resulting from a reduced hydrological cycle during the ice ages.

Orbital and millennial Antarctic climate variability over the past 800,000 years.

A high-resolution deuterium profile is now available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage 20.2, approximately 800,000 years ago. Experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation. We assessed the general correspondence between Dansgaard-Oeschger events and their smoothed Antarctic counterparts for this Dome C record, which reveals the presence of such features with similar amplitudes during previous glacial periods. We suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records.

Southern Ocean sea-ice extent, productivity and iron flux over the past eight glacial cycles.

Sea ice and dust flux increased greatly in the Southern Ocean during the last glacial period. Palaeorecords provide contradictory evidence about marine productivity in this region, but beyond one glacial cycle, data were sparse. Here we present continuous chemical proxy data spanning the last eight glacial cycles (740,000 years) from the Dome C Antarctic ice core. These data constrain winter sea-ice extent in the Indian Ocean, Southern Ocean biogenic productivity and Patagonian climatic conditions. We found that maximum sea-ice extent is closely tied to Antarctic temperature on multi-millennial timescales, but less so on shorter timescales. Biological dimethylsulphide emissions south of the polar front seem to have changed little with climate, suggesting that sulphur compounds were not active in climate regulation. We observe large glacial-interglacial contrasts in iron deposition, which we infer reflects strongly changing Patagonian conditions. During glacial terminations, changes in Patagonia apparently preceded sea-ice reduction, indicating that multiple mechanisms may be responsible for different phases of CO2 increase during glacial terminations. We observe no changes in internal climatic feedbacks that could have caused the change in amplitude of Antarctic temperature variations observed 440,000 years ago.

Linking retinotopic fMRI mapping and anatomical probability maps of human occipital areas V1 and V2.

Using functional MRI, we characterized field sign maps of the occipital cortex and created three-dimensional maps of these areas. By averaging the individual maps into group maps, probability maps of functionally defined V1 or V2 were determined and compared to anatomical probability maps of Brodmann areas BA17 and BA18 derived from cytoarchitectonic analysis (Amunts, K., Malikovic, A., Mohlberg, H., Schormann, T., Zilles, K., 2000. Brodmann's areas 17 and 18 brought into stereotaxic space-where and how variable? NeuroImage 11, 66-84). Comparison of areas BA17/V1 and BA18/V2 revealed good agreement of the anatomical and functional probability maps. Taking into account that our functional stimulation (due to constraints of the visual angle of stimulation achievable in the MR scanner) only identified parts of V1 and V2, for statistical evaluation of the spatial correlation of V1 and BA17, or V2 and BA18, respectively, the a priori measure kappa was calculated testing the hypothesis that a region can only be part of functionally defined V1 or V2 if it is also in anatomically defined BA17 or BA18, respectively. kappa = 1 means the hypothesis is fully true, kappa = 0 means functionally and anatomically defined visual areas are independent. When applying this measure to the probability maps, kappa was equal to 0.84 for both V1/BA17 and V2/BA18. The data thus show a good correspondence of functionally and anatomically derived segregations of early visual processing areas and serve as a basis for employing anatomical probability maps of V1 and V2 in group analyses to characterize functional activations of early visual processing areas.

High-resolution record of Northern Hemisphere climate extending into the last interglacial period.

Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5 degrees C warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time.

Strong hemispheric coupling of glacial climate through freshwater discharge and ocean circulation.

The climate of the last glacial period was extremely variable, characterized by abrupt warming events in the Northern Hemisphere, accompanied by slower temperature changes in Antarctica and variations of global sea level. It is generally accepted that this millennial-scale climate variability was caused by abrupt changes in the ocean thermohaline circulation. Here we use a coupled ocean-atmosphere-sea ice model to show that freshwater discharge into the North Atlantic Ocean, in addition to a reduction of the thermohaline circulation, has a direct effect on Southern Ocean temperature. The related anomalous oceanic southward heat transport arises from a zonal density gradient in the subtropical North Atlantic caused by a fast wave-adjustment process. We present an extended and quantitative bipolar seesaw concept that explains the timing and amplitude of Greenland and Antarctic temperature changes, the slow changes in Antarctic temperature and its similarity to sea level, as well as a possible time lag of sea level with respect to Antarctic temperature during Marine Isotope Stage 3.

Abrupt climate change.

Large, abrupt, and widespread climate changes with major impacts have occurred repeatedly in the past, when the Earth system was forced across thresholds. Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events. Were such an event to recur, the economic and ecological impacts could be large and potentially serious. Unpredictability exhibited near climate thresholds in simple models shows that some uncertainty will always be associated with projections. In light of these uncertainties, policy-makers should consider expanding research into abrupt climate change, improving monitoring systems, and taking actions designed to enhance the adaptability and resilience of ecosystems and economies.

Atmospheric CO2 concentrations over the last glacial termination.

A record of atmospheric carbon dioxide (CO2) concentration during the transition from the Last Glacial Maximum to the Holocene, obtained from the Dome Concordia, Antarctica, ice core, reveals that an increase of 76 parts per million by volume occurred over a period of 6000 years in four clearly distinguishable intervals. The close correlation between CO2 concentration and Antarctic temperature indicates that the Southern Ocean played an important role in causing the CO2 increase. However, the similarity of changes in CO2 concentration and variations of atmospheric methane concentration suggests that processes in the tropics and in the Northern Hemisphere, where the main sources for methane are located, also had substantial effects on atmospheric CO2 concentrations.

Activity of the hypothalamic-pituitary-adrenal axis is altered by aging and exposure to social stress in female rhesus monkeys.

Age-related changes in glucocorticoid negative feedback inhibition of hypothalamic CRF and pituitary ACTH are observed in rodents. Attempts to study similar effects in humans have produced mixed results due in part to the difficulty in matching older subjects on social and lifestyle variables. The present study used female rhesus monkeys as a model for women by comparing young adult (n = 20) to old (n = 20) females to test the hypotheses that the hypothalamic-pituitary-adrenal axis is altered in older animals and that this difference is exacerbated by exposure to social stress. The effects of age on the response to two doses of dexamethasone and two doses of CRF were assessed in females living in a stable social environment (control) and in socially stressed females removed from their group and housed temporarily in a remote, nonsocial environment (separated). The suppression of serum cortisol was not different between the two doses of dexamethasone. Before dexamethasone administration (2100 h), serum cortisol was significantly higher in old control females than in either young or old separated females, who were not different from one another. The young control females had baseline cortisol concentrations significantly lower than all other groups. Serum cortisol was suppressed approximately 75% below baseline values in all groups by 10 h after dexamethasone administration. Age significantly affected serum cortisol after dexamethasone, as the old control group showed a release from suppression 19 h posttreatment compared to the young control group and compared to the separated groups. Social condition had a significant effect on the responses of serum cortisol and plasma ACTH to CRF administration. At baseline (0930 h), serum cortisol was significantly higher in young controls compared with older controls, with both separated groups having intermediate values. Similarly, plasma ACTH at baseline was significantly higher in young controls compared to all other groups. Social separation significantly diminished the elevation of both serum cortisol and ACTH after stimulation with either dose of CRF. Control females showed a prolonged increase in plasma ACTH through 60 min and an increase in serum cortisol through 120 min after CRF. In contrast, these hormones either declined by 60 min or did not increase in socially separated females after CRF administration. These data suggest that the circadian rhythm in serum cortisol may be affected by aging, as levels were higher in the evening and lower in the morning in old control compared to young control females. The effect of age on the response to dexamethasone treatment among the control groups lends support to the hypothesis that the sensitivity of glucocorticoid negative feedback diminishes with aging. Although age did not affect the response to CRF, social separation diminished the elevation in both serum cortisol and plasma ACTH. Whether this effect was due to stress-induced down-regulation of pituitary CRF receptors remains to be determined.

Abrupt climate change in the computer: is it real?

Models suggest that dramatic changes in the ocean circulation are responsible for abrupt climate changes during the last ice age and may possibly alter the relative climate stability of the last 10,000 years.