bluuebunny/crossref_metadata_2025 huggingface dataset:
Welfare Index and Reproductive Performance in the Sow
Authors: Munsterhjelm C , Valros A , Heinonen M , Hälli O , Peltoniemi OAT
Published: August 2006

Contents

To study the relationship between on‐farm welfare and reproductive performance in the sow, the TGI 35L Animal Needs Index was modified for use in Finnish pig production. The modified index had a maximal total score of 100. It was comprised of six categories: ‘locomotion’ (maximal score 21 for dry sows and 11 for lactating sows), ‘social interaction’ (12/8), ‘floor quality’ (16/9), ‘stable climate’ (16/21), ‘feeding’ (16/23) and ‘health and stockmanship’ (19/29). Index scorings were performed separately in farrowing, breeding and gestation units on 28 representative Finnish sow farms. One‐year production parameters were collected. Multiple linear regression was used for statistical analysis. Total ANI‐points varied between 36.5–68.0 for lactating and 39.5–86.0 for dry sows. Litter size increased with increasing scores for ‘feeding’ in the dry sow unit. Controlling for breed, high scores for ‘health and stockmanship’ and ‘floor quality’ shortened the reproductive cycle, probably because of good leg health. The number of weaned piglets per sow per year (PSY) increased with increasing scores for dry sow ‘health and stockmanship’, ‘floor quality’ and an interaction of ‘feeding’ in the farrowing and mating units. PSY increased with decreasing scores for farrowing pen ‘climate’. High‐quality floors and stockmanship appear to correlate positively with reproductive performance in the sow. Effects of a welfare‐promoting feeding strategy on reproduction are contradictory.
Teaching Bovine Rectal Palpation with Live Cows in the Slaughterhouse: Is it Worthwhile?
Authors: Lopes G , Rocha A
Published: August 2006

Contents

Bovine rectal palpation, a procedure that requires considerable practice to develop the necessary skills, is often taught during extramural activities, or even learnt in practice after graduation. However, student access to cows in extramural activities may be limited because of student numbers, animal welfare considerations and concerns over induction of embryo mortality because of inexperience of the student. To overcome some of these limitations, in our school practical classes of bovine rectal palpation are taught in a slaughterhouse, with small groups of approximately 10 students per class, over a period of 30 weeks. Number of cows palpated, type of cases found and the success rate of students in the final practical exam were recorded and analysed for 3 years, and contrasted with the pre‐established goals for the course. Additionally, a questionnaire was sent to former students to assess their opinion on the usefulness of the palpation course, as well as to identify main learning difficulties and collect suggestions to improve teaching methods. Overall, the information obtained indicated that the course is useful to teach palpation skills, even if the original goals may have been very optimistic. Most (96%) of the respondents had the opinion that the course was very useful or useful. Several suggestions were offered to improve teaching methods, but there was no consensus on a single recommendation. Despite the fact that a considerable number of respondents to the questionnaire did not use bovine rectal palpation in their practice, only one considered the classes ‘not useful’. It is concluded that this method of teaching rectal palpation should be continued and the teaching methods improved with the adoption of some modifications.
Examining the metabolic syndrome in Russia
Authors: Jones Ellen D , Ivanov L Louise , Wallace Debra C , VonCannon Lois
Published: August 2006

The purpose of this study was to examine the prevalence of the metabolic syndrome and its components among residents of a small town in Russia. A descriptive design was used to examine the metabolic syndrome and its components among a convenience sample of adults aged ≥ 18 years. Health assessments and screenings were conducted in a rural health clinic in southern Russia. Data on blood pressure, fasting glucose, HDL cholesterol, triglyceride cholesterol and central obesity were collected, as well as demographic, health history and lifestyle information. 147 persons chose to participate. The majority of participants were female and 92% were ≥ 47 years of age. Many persons suffered from three or more metabolic syndrome components, with hypertension the most common metabolic syndrome component. In conclusion, patients at the clinic were at risk for developing cardiac disease. Health screening and health education for cardiovascular and diabetes risk is needed to assist this population in decreasing their metabolic syndrome and its consequential effects.
The role of the student: Salutogenic or pathogenic?
Authors: Natvig Gerd Karin , Hanestad Berit Rokne , Samdal Oddrun
Published: August 2006

Associations between sense of coherence (SOC) and school‐related resources (supportive school environment, adequate learning conditions) and stress (pressure of schoolwork, bored of school) were explored in a representative sample of 4116 Norwegian school adolescents, aged 11, 13 and 15 years. The students participated in the World Health Organization Cross‐National Survey ‘Health Behaviour in School‐Aged Children 1997/98 (HBSC)’. Multiple linear regression analyses were applied. In unadjusted analyses, all resources and stress factors were significantly related to SOC. In analyses adjusted for all these factors, support from teacher was the only variable that did not remain significant. The strongest and most adverse association with SOC was seen in the relation with feeling pressured by schoolwork among both genders. The next strongest associations were found with support from peers and adequate expectations. In general, the associations with SOC were stronger among girls than boys, but a similar tendency was found for both genders. Implications for school health promotion are discussed.
Nurses’ responses to people with cancer who use complementary and alternative medicine
Authors: Cindy Wang Shou‐Yu , Yates Patsy
Published: August 2006

There is a growing demand for complementary and alternative medicines (CAMs) among people with cancer. This study aims to describe how nurses’ respond to people with cancer who use CAMs, and the factors which might contribute to these different responses. A grounded theory approach was used. Six semistructured interviews were conducted with nurses who were working in cancer settings. The core category which emerged from this study was ‘nurses’ responses towards patients who use CAMs’. Nurses respond in a variety of ways to patients who use CAMs. They include: open, sceptical and ambivalent responses. A range of factors which influence the way nurses respond were also identified. These include the ambiguous definitions of CAM, nurses’ personal philosophies, life experiences, evidence of the therapy’s effectiveness, impact on patients, the motives of patients who use CAM and organizational culture. Several implications for nursing education and practice are identified from these findings.
Cell death in pancreatitis: Effects of alcohol
Authors: Gukovskaya Anna S , Mareninova Olga A , Odinokova Irina V , Sung Kai‐Feng , Lugea Aurelia , Fischer Lars , Wang Yan‐Ling , Gukovsky Ilya , Pandol Stephen J
Published: August 2006

Pancreatitis is a severe and frequently lethal disorder, a major cause of which is alcohol abuse. Parenchymal cell death is a major complication of pancreatitis. In experimental models of (non‐alcoholic) acute pancreatitis, acinar cells have been shown to die through both necrosis and apoptosis, the two principal pathways of cell death. The severity of experimental acute pancreatitis correlates directly with the extent of necrosis and inversely with apoptosis. Thus, understanding the regulation of apoptosis and necrosis, and whether it is possible to manipulate the pattern of death responses, is becoming exceedingly important in investigations of the pathogenesis and treatment of pancreatitis. The effects of alcohol on cell death responses of pancreatitis, and the mechanisms that may mediate these effects, are just starting to be explored. This paper reviews the signaling pathways mediating the balance between apoptosis and necrosis in acute pancreatitis, and alcohol’s effects on cell death responses in pancreatitis.
In vivo imaging of hepatic fatty acid metabolism in patients with non‐alcoholic steatohepatitis using semiquantitative 123I‐labeled branched‐chain fatty acid analog
Authors: Onishi Saburo , Saibara Toshiji
Published: August 2006

Obesity is now prevailing worldwide, coincident with the increase of hepatic steatosis. Metabolic syndrome with obesity and hypertension, hyperlipidemia, and impaired glucose tolerance is one of the most frequent life‐threatening diseases and non‐alcoholic steatohepatitis is believed to be a hepatic expression of this syndrome. Non‐alcoholic steatohepatitis is prevalent and well characterized in Caucasians, but little is known about non‐alcoholic steatohepatitis in Asia–Oceania. Obesity will be a serious social problem in Asia–Oceania in the next two decades and we need to prevent the increase of this syndrome. Therefore, it is extremely important to know about non‐alcoholic steatohepatitis based on racial differences, because this syndrome is likely to be a multi‐factorial syndrome resulting from different combinations of susceptibility genes superimposed on different environmental factors. Because hepatic steatosis is the first step in the development of not only metabolic syndrome but also non‐alcoholic steatohepatitis, the genetic background of Japanese NASH patients was investigated and a measure to assess fatty acid β‐oxidation in the liver in vivo was developed.
Update on pancreatic cancer and alcohol‐associated risk
Authors: Welsch Thilo , Kleeff Jörg , Seitz Helmut K , Büchler Peter , Friess Helmut , Büchler Markus W
Published: August 2006

Ductal adenocarcinoma of the pancreas is characterized by extremely aggressive behavior, with an overall 5‐year survival of <4%. Because conventional and specifically tailored therapeutic regimens have little impact on patient survival, epidemiological and molecular research aims at identifying and reducing risk factors. Cigarette smoking, obesity, diabetes mellitus, and chronic pancreatitis are amenable to medical prevention or therapy. Heavy alcohol consumption is an inconsistent single risk factor for pancreatic cancer but may promote carcinogenesis by increasing the risk of diabetes mellitus or chronic pancreatitis. For various agents, the key carcinogenic effect is probably an inflammatory response in the pancreatic tissue. On the molecular level, mutations of oncogenes and tumor suppressor genes, as well as various epigenetic alterations, such as overexpression of growth factors and their receptors, are important in tumorigenesis. Complete and safe surgical resection, together with adjuvant therapy, offers prolonged survival, with 5‐year survival rates of approximately 25%. However, for unresectable or disseminated disease, which constitutes the vast majority of cases, treatment is palliative. Despite increasing knowledge about the molecular pathology of pancreatic cancer and despite advances in treatment, the overall course of the disease is dismal, and reinforced efforts to reduce incidence and improve outcome are needed desperately.
Vacuolar adenosine triphosphatase and pancreatic acinar cell function
Authors: Gorelick Fred S , Shugrue Christine A , Kolodecik Thomas R , Thrower Edwin C
Published: August 2006

The pathologic activation of proteases within the pancreatic acinar cell is a key initiating event in acute pancreatitis. Past studies have suggested that the generation of a low‐pH environment is critical to this process. Vacuolar adenosine triphosphatase (vATPase) is a multiprotein complex that transports protons across cellular membranes. Activation of the vATPase requires assembly of the soluble (V1) subunits on the membrane subunits (V0). It is found that conditions that cause protease activation in the acinar cell also cause assembly of V1 on V0. Further, inhibitors of vATPase block this protease activation. Ethanol and butanol sensitize the acinar cell to cholecystokinin‐induced zymogen activation; vATPase inhibitors also blocked this activation. Activation of the vATPase may be central to the pathologic activation of proteases in the acinar cell and may also modulate the sensitizing effects of alcohols.
Role of Ca2+ in pancreatic cell death induced by alcohol metabolites
Authors: Criddle David N , Sutton Robert , Petersen Ole H
Published: August 2006

Whereas alcohol itself, even in high concentrations, has little effect on the functional performance of isolated pancreatic acinar cells, non‐oxidative metabolites (fatty acid ethyl esters [FAEE] and fatty acids [FA]) can cause Ca2+‐dependent necrosis. The mechanism of action of FAEE has been investigated using a combination of patch clamp whole‐cell current recording and Ca2+ imaging. At low stimulation intensities, FAEE evoke repetitive short‐lasting cytosolic Ca2+ spikes, which are inhibited by caffeine, used as an inositol trisphosphate receptor antagonist. With more intense stimulation, sustained elevations of the cytosolic Ca2+ concentration are observed, which can be prevented by pharmacological inhibition of the conversion of FAEE to FA. It is therefore the FA and not the FAEE that cause necrosis. The effect of FA cannot be blocked by inositol trisphosphate receptor antagonists. Fatty acids elicit a marked reduction in the cytosolic adenosine triphosphate (ATP) level. The patch clamp experiments show that the toxic sustained Ca2+ signal generation induced by FA can be prevented by adding ATP to the cell interior. The toxic alcohol effects are principally due to FAEE produced under non‐oxidative conditions and their subsequent conversion to FA. The FA‐induced necrosis is Ca2+‐dependent. The destructive sustained Ca2+ signals are due to inhibition of mitochondrial function with failure of ATP generation.
SPINK1 gene mutations and pancreatitis in Japan
Authors: Shimosegawa Tooru , Kume Kiyoshi , Masamune Atsushi
Published: August 2006

SPINK1 can inhibit up to 20% of trypsin activity, and may constitute one major mechanism to protect the pancreas from autodigestion. In 2000, Witt et al. first recognized the association between mutations in the SPINK1 gene and chronic pancreatitis (CP), but the significance of SPINK1 gene mutation in pancreatitis and its relation to alcohol consumption remains unclear in Japan. The aim of the present paper was to clarify the incidence of SPINK1 mutations in CP patients with various etiologies in Japan and, in addition, to examine the relationship between alcohol metabolism and the polymorphisms in the key enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase‐2 (ALDH2). A total of 156 patients with CP, and 165 healthy volunteers, all Japanese, were examined for the SPINK1 mutations by polymerase chain reaction–restriction fragment length polymorphism and direct sequencing. In Japan, the prevalence of [N34S; IVS1–37T > C] and [−215G > A; IVS3 + 2T > C] was significantly higher in patients with idiopathic CP (10.6% and 12.8%, respectively) than normal subjects (0.6% and 0%). The frequency of the [−215G > A; IVS3 + 2T > C] mutation in Japan was significantly higher than that reported in other populations. Concerning alcoholic CP, the [−215G > A; IVS3 + 2T > C] mutation was found in only a small number of patients (3.9%). On analysis of ADH2 and ALDH2 gene polymorphisms an association was found between ADH2*2 allele and alcoholic CP, and the ADH2*2/2*2 genotype had a tendency to increase the risk of developing pancreatic pseudocyst. In conclusion, in Japan the [−215G > A; IVS3 + 2T > C] mutation in the SPINK1 gene may form a unique genetic background for pancreatitis.
Cytochrome P450 2E1‐dependent oxidant stress and upregulation of anti‐oxidant defense in liver cells
Authors: Cederbaum Arthur I
Published: August 2006

Induction of cytochrome P450 2E1 (CYP2E1) is a central pathway by which ethanol generates oxidative stress. Cytochrome P450 2E1 metabolizes many other toxicologic compounds. Toxicity of these agents is enhanced by ethanol, due to induction of CYP2E1. Cytochrome P450 2E1 is induced under a variety of physiological and pathophysiological conditions. The laboratory at Mount Sinai School of Medicine established HepG2 cell lines that constitutively express human CYP2E1. Ethanol, polyunsaturated fatty acids and iron were toxic to the HepG2 cells that express CYP2E1 (E47 cells) but not control HepG2 cells. The E47 cells had higher glutathione levels than control HepG2 cells due to activation of the genes encoding the heavy and light subunits of gamma glutamyl cysteine synthetase (GCLC and GCLM). There was also a twofold increase in catalase, cytosolic and microsomal glutathione transferase, and heme oxygenase‐1 (HO‐1) in the E47 cells due to activation of their respective genes. These activations were prevented by anti‐oxidants, suggesting that the upregulation of these anti‐oxidant genes may reflect an adaptive mechanism to remove CYP2E1‐derived oxidants. Increases in nuclear factor erythroid 2‐related factor 2 (Nrf2) protein and mRNA were observed in livers of hepatocytes of chronic alcohol‐fed and of pyrazole‐treated rats or mice, conditions known to elevate CYP2E1. E47 cells showed increased Nrf2 mRNA and protein expression. Upregulation of GCLC and HO‐1 in E47 cells is dependent on Nrf2. These results suggest that Nrf2 is activated and its levels are increased when CYP2E1 is elevated. It is suggested that Nrf2 plays a key role in the adaptive response against increased oxidative stress caused by CYP2E1.
Two proxy records revealing the late Holocene fire history at a site on the central coast of New South Wales, Australia
Authors: MOONEY SCOTT. D. , MALTBY EMMA L.
Published: August 2006

Abstract:  The local fire history of a coastal swamp catchment in New South Wales was reconstructed using two proxy records of fire: sedimentary macroscopic charcoal and fire‐scar analyses of Xanthorrhoea johnsonii. The charcoal analysis provided a record of fire activity spanning the last 2800 years, while the Xanthorrhoea record covered the last approx. 300 years. The ability of each method to accurately record fire events was verified by cross referencing against the recent (post 1968) historic fire record. Fire history was then extrapolated beyond the historic record, to reveal an unprecedented level of fire activity in the last 35 years, which coincides with increased human activity in the area. In the prehistoric period charcoal and fire scars are comparatively rare, which is most parsimoniously ascribed to little fire activity, but perhaps represents skilful fire manipulation, as is often attributed to Aboriginal people. The comparatively minor fluctuations in macroscopic charcoal during the prehistoric period were approximately coeval with previous evidence of late Holocene environmental change in south‐eastern Australia, suggesting that fire frequency at the site responded to climatic variability. The longer temporal perspective of this palaeoenvironmental approach provides information for the contemporary management of fire in this conservation reserve.
Effect of fire on benthic algal assemblage structure and recolonization in intermittent streams
Authors: COWELL AMANDA L. , MATTHEWS TY G. , LIND PETER R.
Published: August 2006

Abstract:  Dry biofilm on rocks and other substrata forms an important drought refuge for benthic algae in intermittent streams following the cessation of flow. This dry biofilm is potentially susceptible to disturbance from bushfires, including direct burning and/or scorching and damage from radiant heat, particularly when streams are dry. Therefore, damage to dry biofilms by fire has the potential to influence algal recolonization and assemblage structure in intermittent streams following commencement of flow. The influence of fire on benthic algal assemblages and recolonization was examined in intermittent streams of the Grampians National Park, Victoria, Australia, using a field survey and manipulative field experiment. The field survey compared assemblages in two intermittent streams within a recently burnt area (within 5 months of the fire) with two intermittent streams within an unburnt area. The two burnt streams were still flowing during the fire so most biofilms were not likely to be directly exposed to flames. Considerable site‐to‐site and stream‐to‐stream variation was detected during the field survey, which may have obscured potential differences attributable to indirect effects of the fire. The manipulative field experiment occurred in two intermittent streams and consisted of five treatments chosen to replicate various characteristics of bushfires that may influence dry biofilms: dry biofilm exposed directly to fire; dry biofilm exposed to radiant heat; dry biofilm exposed to ash; and two procedural controls. After exposure to the different treatments, rocks were replaced in the streams and algae were sampled 7 days after flow commenced. Differences occurred across treatments, but treatment differences were inconsistent across the two streams. For example, direct exposure to fire reduced the abundance of recolonizing algae and altered assemblage structure in both streams, while radiant heat had an effect on assemblage structure in one stream only. The manipulative field experiment is likely to have represented the intensity of a small bushfire only. Nonetheless, significant differences across treatments were detected, so these experimental results suggest that fire can damage dry biofilms, and hence, influence algal recolonization and assemblage structure in intermittent streams.
Species and community responses to short‐term climate manipulation: Microarthropods in the sub‐Antarctic
Authors: MCGEOCH MELODIE A. , LE ROUX PETER C. , HUGO ELIZABETH A. , CHOWN STEVEN L.
Published: August 2006

Abstract: Both species and community‐level investigations are important for understanding the biotic impacts of climate change, because current evidence suggests that individual species responses are idiosyncratic. However, few studies of climate change impacts have been conducted on entire terrestrial arthropod communities living in the same habitat in the southern Hemisphere, and the effects of precipitation changes on them are particularly poorly understood. Here we investigate the species‐ and community‐level responses of microarthropods inhabiting a keystone plant species, on sub‐Antarctic Marion Island, to experimental reduction in precipitation, warming and shading. These climate manipulations were chosen based on observed climate trends and predicted indirect climate change impacts on this system. The dry‐warm and shade inducing treatments that were imposed effected significant species‐ and community‐level responses after a single year. Although the strongest community‐level trends included a dramatic decline in springtail abundance and total biomass under the dry‐warm and shade treatments, species responses were generally individualistic, that is, springtails responded differently to mites, and particular mite and springtail species responded differently to each other. Our results therefore provide additional support for the dynamic rather than static model for community responses to climate change, in the first such experiment in the sub‐Antarctic. In conclusion, these results show that an ongoing decline in precipitation and increase in temperature is likely to have dramatic direct and indirect effects on this microarthropod community. Moreover, they indicate that while at a broad scale it may be possible to make generalizations regarding species responses to climate change, these generalizations are unlikely to translate into predictable effects at the community level.
Habitat avoidance of an introduced weed by native lizards
Authors: VALENTINE LEONIE E.
Published: August 2006

Abstract:  Rubber vine (Cryptostegia grandiflora) is an environmental weed that frequently invades riparian habitats in northern Australia. I examined the habitat use of lizards in riparian and woodland environments comprised of native and rubber vine vegetation. Rubber vine was a major component of vegetation in the riparian habitat (approximately 40%), but only a minor component of woodland habitat (approximately 5%). Of 132 lizards, none were observed using rubber vine vegetation in riparian habitats, significantly less than expected, and only one lizard was observed in rubber vine vegetation in the woodland habitat. As rubber vine vegetation contains features that superficially resemble native habitat used by lizards, such as leaf litter, the avoidance of rubber vine by lizards suggests that rubber vine has underlying characteristics that create a suboptimal environment for lizards.
Immediate and short‐term responses of bird and mammal assemblages to a subalpine wildfire in the Snowy Mountains, Australia
Authors: GREEN KEN , SANECKI GLENN
Published: August 2006

Abstract  Over 35 days in January–February 2003, wildfires burnt across much of the subalpine/alpine landscape of south‐eastern Australia, including about 70% of the land above 1500 m in the Snowy Mountains. At the time of the fire, studies of two subalpine faunal assemblages were being undertaken. The opportunity to resurvey the assemblages was taken in order to examine the immediate impact of fire in an environment where it is uncommon but predicted to occur increasingly with global warming. A study area in the Whites River Valley, where the number of bird species was counted monthly from 1996 to 2003, and weekly in late winter–spring from 2000 to 2003, was burnt in one fire. As well as the expected decrease in the number of individual birds, the fire resulted in an immediate decrease in the number of bird species, unlike in previously studied montane forest, with only the regularly wintering species plus the olive whistler and the ground‐feeding flame robin remaining. During the post‐winter avian immigration, few regular spring migrants appeared on burnt sites despite their nearby presence on the unburnt side of the valley. Five of six small mammal trapping grids were burnt. As with fires at lower altitudes, there was an immediate reduction in mammal numbers on burnt grids following the fire, but in addition, one species, Mastacomys fuscus, declined further in the ensuing 2 months both on burnt and unburnt sites. Numbers of Antechinus swainsonii and Rattus fuscipes stabilized until autumn/winter when there was a further decline due to the unavailability of subnivean space to allow winter foraging, allied with a concentration of fox predation on areas still carrying populations of small mammals.
Current distribution and potential extent of the most invasive alien plant species on La Réunion (Indian Ocean, Mascarene islands)
Authors: BARET STEPHANE , ROUGET MATHIEU , RICHARDSON DAVID M. , LAVERGNE CHRISTOPHE , EGOH BENIS , DUPONT JOEL , STRASBERG DOMINIQUE
Published: August 2006

Abstract  La Réunion Island has the largest area of intact vegetation of the islands in the Mascarene archipelago. Biological invasions are the primary threat to biodiversity in the intact habitats of the island (those not already transformed by agriculture and urbanization). Our study aimed to identify areas to prioritize in managing invasive alien plants for biodiversity conservation. We used extensive surveys of 238 distinct untransformed areas on La Réunion to define the current distribution patterns of all invasive species. Using expert knowledge, we compiled maps of the current distribution of the 46 most widespread/important invasive plants at the habitat scale (identified according to vegetation structure). Data from 440 botanical relevés for the 20 most threatening invasive alien plant species across the island and climatic envelope models were used to derive climatic suitability surfaces; these were used to map potential distributions for these species. More than 10 species invade 16.7% of the remaining habitat. Five habitat types are invaded by 25 or more species, and eight have fewer than 10 invasive alien plant species. Cluster analysis based on presence/absence of species in the 18 habitat types produced eight groups of species that invade particular habitats. Potential distribution models show that some species have invaded large parts of their potential range (e.g. Fuchsia magellanica, Furcraea foetida, Hiptage benghalensis), whereas others have the potential to increase their range substantially (e.g. Clidemia hirta, Strobilanthes hamiltonianus, Ulex europaeus). Management implications are identified for both groups. Three broad groups of habitats were identified: (i) intact habitats with a low level of invasion (e.g. subalpine shrubland); (ii) moderately invaded habitats with varying levels of intactness (ranging from windward submountain rainforest to the Acacia heterophylla forest); and (iii) habitats with little remaining intact area and high levels of invasion (e.g. lowland rainforest). Different management interventions are appropriate for these three groups.
High Nothofagusﬂower consumption and pollen emptying in the southern South American austral parakeet (Enicognathus ferrugineus)
Authors: DÍAZ SOLEDAD , KITZBERGER THOMAS
Published: August 2006

Abstract  We describe extraordinary aspects of the feeding ecology of the austral parakeet, Enicognathus ferrugineus– the most southerly distributed psittacid in the world – that allow this endemic species to inhabit and become a common bird in relatively species‐poor temperate and subantarctic Nothofagus forests of South America. We used two sources of information to analyse temporal and spatial dietary changes of austral parakeets in subalpine forests near Lake Distric of southern Argentina: (i) relative abundance of parakeet foraging on the forest ﬂoor along an altitudinal transect from 1000 to 1420 m; and (ii) faeces analyses of seasonal collections. Austral parakeets largely relied on a protein‐rich pollen‐based spring–early summer diet by destructively harvesting large quantities of wind‐pollinated Nothofagus pumilioﬂowers and efficiently emptying pollen grains – specializations previously described only in pollinating nectarivorous vertebrates. Pollen emptying rates (c. 65%) were the highest reported for psittacids and among the highest for vertebrates in general. Parakeets made extended use of short‐lived N. pumilioﬂowers by tracking the altitudinal shifts in ﬂowering phenology. Additionally, parakeets complemented their diet with carbohydrates from N. pumilio insect exudates. By late summer, parakeets switched to a lipid‐rich diet based on N. pumilio seeds. This resource remained available through mid‐autumn because parakeets also followed in altitude the phenological delays in fruiting. In winter, parakeets fed on N. pumilio parasitic Misodendrum mistletoe buds and leaves and Cyttaria sp. parasitic canopy fungi. These results suggest that stringent food availability in these relatively high latitudes may have led to behavioural and physiological specializations of austral parakeets to obtain year‐round food resources efficiently from Nothofagus trees.
Effects of the Neotyphodium endophyte fungus on dormancy and germination rate of Lolium multiflorum seeds
Authors: GUNDEL PEDRO E. , MASEDA PABLO H. , GHERSA CLAUDIO M. , BENECH‐ARNOLD ROBERTO L.
Published: August 2006

Abstract  Neotyphodium frequently occurs as an endophyte in grasses. Evidence shows enhanced fitness of endophyte infected grasses relative to non‐infected ones. Some studies of seed germination show endophyte enhancement of plant fitness in various environments, but inconsistent results indicate that further studies are needed. So far, experiments have failed to separate the confounded effects of population origin and seed management. For this reason, we evaluated the effects of endophyte infection on seed dormancy and germination in Lolium multiflorum using an experimental design controlling these factors. Depending on the year of seed production, endophyte infection modified seed response to light quality, affecting predominantly seed dormancy levels. Nevertheless, the endophyte did not affect base temperature or thermal time of germination. We concluded that endophytes were not a strong influence on germination behaviour. We speculate from our results that the presence of the endophyte changes germination by an indirect effect, in extending growth of the maternal plant during seed development and ripening. The direct effect of hyphae in the seed on seed behaviour was disregarded, because the difference between infected and non‐infected seed varied within the year of seed production. Future experiments should focus on effects of the endophyte on the canopy of parent plants during seed production and ripening, and, hence, on subsequent dormancy and germination of the seeds.
Extrafloral nectaries as a deterrent mechanism against seed predators in the chemically protected weed Crotalaria pallida (Leguminosae)
Authors: GUIMARÃES PAULO R. , RAIMUNDO RAFAEL L. G. , BOTTCHER CLÁUDIA , SILVA ROGÉRIO R. , TRIGO JOSÉ R.
Published: August 2006

Abstract  In several plants, extrafloral nectaries (EFN) are located close to the reproductive structures, suggesting that ants may act as a defence against specialized seed predators that overcome chemical defences. Alternatively, ants may also deter herbivores in a generalized manner, thereby protecting the whole plant. In this work, we examined the relationship between the chemically protected weed Crotalaria pallida Ait. (Leguminosae) that bears EFN, its specialized seed predator, the larvae of the arctiid moth Utetheisa ornatrix L. (Arctiidae) and ants. We tested two hypotheses related to the type of deterrence caused by ants. The Seed Predator Deterrence Hypothesis predicts that ant deterrence is directed primarily towards herbivores that destroy seeds and other reproductive structures, without attacking herbivores on vegetative structures. The General Deterrence Hypothesis states that ants are general in their effects, equally deterring herbivores in vegetative and reproductive structures. Our results supported the predictions of the Seed Predator Deterrence Hypothesis, namely, that (i) ant activity on EFN was related to the vulnerability of reproductive structures to attack by U. ornatrix; (ii) ant patrolling was restricted almost entirely to racemes; (iii) ants removed termites used as baits more frequently on racemes than on leaves; and (iv) U. ornatrix larvae were often expulsed from the racemes. These results indicate that EFN can act as another deterrent mechanism in chemically protected plants by promoting the expulsion of specialist seed predators.
Evaluation of macrofaunal effects on leaf litter breakdown rates in aquatic and terrestrial habitats
Authors: RIBAS AUGUSTO C. DE A. , TANAKA MARCEL O. , DE SOUZA ANDRÉA L. T.
Published: August 2006

Abstract Decomposition of the organic matter is a key process in the functioning of aquatic and terrestrial ecosystems, although different factors influence processing rates between and within these habitats. Most patterns were described for temperate regions, with fewer studies in tropical, warmer sites. In this study, we carried out a factorial experiment to compare processing rates of mixed species of leaf litter between terrestrial and aquatic habitats at a tropical site, using ﬁne and coarse mesh cages to allow or prevent colonization by macroinvertebrates. The experiment was followed for 10 weeks, and loss of leaf litter mass through time was evaluated using exponential models. We found no interaction between habitat and mesh size and leaf litter breakdown rates did not differ between ﬁne and coarse mesh cages, suggesting that macroinvertebrates do not influence leaf litter decomposition in either habitat at our studied site. Leaf breakdown rates were faster in aquatic than in terrestrial habitats and the magnitude of these differences were comparable to studies in temperate regions, suggesting that equivalent factors can influence between‐habitat differences detected in our study.
Glutamate regulates retinal progenitors cells proliferation during development
Authors: Martins Rodrigo A. P. , Linden Rafael , Dyer Michael A.
Published: August 2006

The precise coordination of cell cycle exit and cell fate specification is essential for generating the correct proportion of retinal cell types during development. The decision to exit the cell cycle is regulated by intrinsic and extrinsic cues. There is growing evidence that neurotransmitters can regulate cell proliferation and cell fate specification during the early stages of CNS development prior to the formation of synaptic connections. We found that the excitatory neurotransmitter glutamate regulates retinal progenitor cell proliferation during embryonic development of the mouse. AMPA/kainate and N‐methyl‐d‐aspartate receptors are expressed in embryonic retinal progenitor cells. Addition of exogenous glutamate leads to a dose‐dependent decrease in cell proliferation without inducing cell death or activating the p53 pathway. Activation of AMPA/kainate receptors induced retinal progenitor cells to prematurely exit the cell cycle. Using a replication‐incompetent retrovirus to follow the clonal expansion of individual retinal progenitor cells, it was observed that blockade of AMPA/kainate receptors increased the proportion of large clones, showing that modulation of endogenous glutamatergic activity can have long‐term consequences on retinal cell proliferation. Real time reverse transcriptase‐polymerase chain reaction and immunoblot analyses demonstrated that glutamate does not alter the levels of the mRNA and proteins that regulate the G1/S‐phase transition. Instead, the activity of the Cdk2 kinase is reduced in the presence of glutamate. These data indicate that glutamate regulates retinal progenitor cell proliferation by post‐translational modulation of cyclin/Cdk2 kinase activity.
Hypo‐response of the hypothalamic‐pituitary‐adrenocortical axis after an ethanol challenge in prenatally stressed adolescent male rats
Authors: Van Waes Vincent , Enache Mihaela , Dutriez Isabelle , Lesage Jean , Morley‐Fletcher Sara , Vinner Elisabeth , Lhermitte Michel , Vieau Didier , Maccari Stefania , Darnaudéry Muriel
Published: August 2006

The period of adolescence and environmental factors, such as stress, are important in determining ethanol vulnerability in both humans and rats. Ethanol is a powerful activator of the hypothalamic‐pituitary‐adrenal (HPA) axis but attenuated responses of the HPA axis to ethanol have been described in populations with a high risk of ethanol abuse. In rats, prenatal stress leads to prolonged stress‐induced corticosterone secretion and increases the vulnerability to drugs of abuse, such as amphetamine and nicotine in adulthood and 3,4‐methylenedioxymethamphetamine in adolescent rats. The aim of the present study was to assess the impact of a prenatal stress on HPA axis responsiveness to a moderate dose of ethanol (1.5 g/kg i.p.) in adolescent male rats (28 days old). The parameters evaluated were plasma adrenocorticotropic hormone, plasma corticosterone and mRNA expression of HPA axis central markers (mineralocorticoid receptor, glucocorticoid receptor, corticotropin‐releasing hormone and pro‐opiomelanocortin). Contrary to prior expectations, our results demonstrate that prenatal stress blunts the HPA axis responsiveness to a moderate dose of ethanol in adolescent rats in spite of similar blood ethanol levels. These data suggest that prenatal stress may have the opposite effect on the response to stress depending on the attributes of the stressor stimulus. They thus raise questions about the possible impact of prenatal stress on the further development of ethanol vulnerability.
Microglial glutamate uptake is coupled to glutathione synthesis and glutamate release
Authors: Persson Mikael , Sandberg Mats , Hansson Elisabeth , Rönnbäck Lars
Published: August 2006

The physiological function of microglial glutamate uptake has been debated as it is about 10% of that measured for astrocytes. This study addresses how glutamate, taken up from the extracellular space, is utilized by microglia. It was found that purified rat microglia incubated for 60 min with 3H‐glutamate had an increased intracellular accumulation of 3H‐glutamate after 12 h incubation with tumour necrosis factor alpha (TNF‐α) but not after incubation with lipopolysaccharide (LPS). Furthermore, LPS‐ but not TNF‐α‐treated cells showed an increased efflux of 3H‐labelled compounds, presumably glutamate through the XC– system and treatment with LPS or TNF‐α increased the microglial glutathione concentrations and led to an increased incorporation of 3H‐glutamate into glutathione. Depending on the stimuli, 3–6% of the total labelled contents were found in the form of glutathione and 25–35% in the form of glutamate. These results show that microglial glutamate uptake is directly coupled to glutathione synthesis and release of glutamate and/or glutamate metabolites. Additionally, the increased glutathione contents after LPS or TNF‐α treatment were able to reduce microglial cell death after H2O2 challenge, showing a potential (self)‐protective function for microglial glutamate transporter expression and glutathione synthesis.
Hypothalamic–endocrine aspects in Huntington's disease
Authors: Petersén Åsa , Björkqvist Maria
Published: August 2006

Huntington's disease (HD) is a hereditary and fatal disorder caused by an expanded CAG triplet repeat in the HD gene, resulting in a mutant form of the protein huntingtin. Wild‐type and mutant huntingtin are expressed in most tissues of the body but the normal function of huntingtin is not fully known. In HD, the neuropathology is characterized by intranuclear and cytoplasmic inclusions of huntingtin aggregates, and cell death primarily in striatum and cerebral cortex. However, hypothalamic atrophy occurs at early stages of HD with loss of orexin‐ and somatostatin‐containing cell populations. Several symptoms of HD such as sleep disturbances, alterations in circadian rhythm, and weight loss may be due to hypothalamic dysfunction. Endocrine changes including increased cortisol levels, reduced testosterone levels and increased prevalence of diabetes are found in HD patients. In HD mice, alterations in the hypothalamic–pituitary–adrenal axis occurs as well as pancreatic β‐cell and adipocyte dysfunction. Increasing evidence points towards important pathology of the hypothalamus and the endocrine system in HD. As many neuroendocrine factors are secreted into the cerebrospinal fluid, blood and urine, it is possible that their levels may reflect the disease state in the central nervous system. Investigating neuroendocrine changes in HD opens up the possibility of finding biomarkers to evaluate future therapies for HD, as well as of identifying novel targets for therapeutic interventions.
Endogenous opioids encode relative taste preference
Authors: Taha Sharif A. , Norsted Ebba , Lee Lillian S. , Lang Penelope D. , Lee Brian S. , Woolley Joshua D. , Fields Howard L.
Published: August 2006

Endogenous opioid signaling contributes to the neural control of food intake. Opioid signaling is thought to regulate palatability, the reward value of a food item as determined by orosensory cues such as taste and texture. The reward value of a food reflects not only these sensory properties but also the relative value of competing food choices. In the present experiment, we used a consummatory contrast paradigm to manipulate the relative value of a sucrose solution for two groups of rats. Systemic injection of the nonspecific opioid antagonist naltrexone suppressed sucrose intake; for both groups, however, this suppression was selective, occurring only for the relatively more valuable sucrose solution. Our results indicate that endogenous opioid signaling contributes to the encoding of relative reward value.
A pilot study of inhaled methoxyflurane for procedural analgesia in children
Authors: BABL FRANZ , BARNETT PETER , PALMER GRETA , OAKLEY ED , DAVIDSON ANDREW
Published: August 2006

Background:  Methoxyflurane (MF), a potent volatile anesthetic, can be used as an analgesic in subanesthetic concentrations. In Australia, MF is extensively used in children and adults as an analgesic in the prehospital setting via a hand‐held inhaler device. We conducted a pilot study to explore its use as a patient controlled analgesic for painful procedures in children in the emergency department (ED).

Methods:  This is a prospective observational case series of children aged 5 years and older requiring procedural analgesia for brief painful procedures. Pain scores, depth of sedation, adverse events and patient, parent and staff satisfaction were assessed as well as consumption of MF measured.

Results:  Fourteen patients (aged 6–13 years) received MF mainly for extremity injuries. Amount of MF consumed ranged from 0.36 to 3.06 g per patient inhaled over 4–25 min. There were no serious adverse events. No patient was deeply sedated. Five patients had mild brief self‐resolving adverse events including agitation, euphoria, blurry vision, dizziness and cough. Four patients with fractures with initial high pain scores (≥6) received MF for bridging analgesia with large drops in pain scores. Four patients who required fracture reductions with initial low scores did not achieve adequate analgesia. The remaining six patients had painful procedures undertaken with satisfactory analgesia.

Conclusions:  On the basis of this small pilot study of MF use in children in the ED, this agent appears to be a powerful analgesic. MF seems most useful as a self‐titrated bridging analgesic agent in patients after extremity trauma. It appears less useful as a procedural agent when patients are unable to anticipate and achieve a sufficient level of analgesia before painful stimulus infliction. Pre‐ and intraprocedure coaching is an important aspect of its use especially if initial pain scores are low.
Ecosystem productivity can be predicted from potential relative growth rate and species abundance
Authors: Vile Denis , Shipley Bill , Garnier Eric
Published: August 2006

We show that ecosystem‐specific aboveground net primary productivity (SANPP, g g−1 day−1, productivity on a per gram basis) can be predicted from species‐level measures of potential relative growth rate (RGRmax), but only if RGRmax is weighted according to the species’ relative abundance. This is in agreement with Grime's mass‐ratio hypothesis. Productivity was measured in 12 sites in a French Mediterranean post‐agricultural succession, while RGRmax was measured on 26 of the most abundant species from this successional sere, grown hydroponically. RGRmax was only weakly correlated (r2 = 0.12, P < 0.05) with field age when species abundance was not considered, but the two variables were strongly correlated (r2 = 0.81, P < 0.001) when the relative abundance of species in each field was taken into account. SANPP also decreased significantly with field age. This resulted in a tight relationship (r2 = 0.77, P < 0.001) between productivity and RGRmax weighted according to species relative biomass contribution. Our study shows that scaling‐up from the potential properties of individual species is possible, and that information on potential and realized species traits can be integrated to predict ecosystem functioning.