bluuebunny/crossref_metadata_2025 huggingface dataset:
Where do I go from here: We've got enough seniors?
Authors: Gillham Selena , Ristevski Eli
Published: September 2007

Objective:  To identify recruitment and retention issues for allied health professionals at two rural health services.

Design:  A qualitative study using semi‐structured interviews was used to collect the data which were analysed using thematic analysis.

Setting:  A regional public health service and a community health service in central eastern Victoria, Australia.

Participants:  Eight final‐year allied health students, 7 allied health or discipline managers, 18 current allied health staff and 10 former allied health staff participated in the interviews. Participants' professional backgrounds included: dentistry, dietetics, occupational therapy, physiotherapy, psychology, social work and speech pathology.

Main outcome measures:  Recruitment and retention themes identified from the interview transcripts.

Results:  Career opportunities and social and community connections were significant for both recruitment and retention of all the participant groups. Financial incentives were important for recruiting staff, while organisational management and policy were important for retaining staff. Health service resources were a specific issue for the recruitment of dentists, but were found to be a significant factor in the retention of all allied health staff.

Conclusion:  A number of strategies can be used by health care organisations in rural areas to recruit staff, including: career progression, mentoring and profession development, connecting people with social networks and providing financial remuneration. To maximise staff retention, it is important to ensure that there are career progression pathways within the organisation, and that organisational management and policy provides support and opportunities for staff. Staff also need to be included as part of a social network in the community.
Diabetes risk factors, diabetes and diabetes care in a rural Australian community
Authors: Simmons David , Bourke Lisa , Yau Edward , Hoodless Mary
Published: September 2007

Objective:  To comprehensively describe diabetes‐related risk factors, quality of care and patient‐perceived barriers to care in a rural community.

Design:  Cross‐sectional mail study, self‐completed survey and retrospective chart review.

Setting:  Community and health services in Corryong, rural Victoria, Australia.

Participants:  Ninety‐seven patients with diabetes and 495 with other diseases in the mail study, 84 with diabetes in the self‐completed survey and 101 diabetic patient chart reviews.

Main outcome measures:  Self‐reported lifestyle activities, uptake of health checks, metabolic measures and uptake of medication, and self‐reported barriers to diabetes care.

Results:  Most residents without diabetes had recently had their blood pressure and cholesterol checked; 60.4% were trying to control their weight and 73.9% were exercising regularly (although only 30.7% to an adequate level). Those with diabetes reported a greater uptake of healthy living messages, and had a mean HbA1c of 7.3%, total cholesterol of 5.0 mmol L

−1

; 12.9% had a diastolic blood pressure ≥85 mmHg. Foot checks were infrequent (18%). There was substantial room to increase antiplatelet, blood pressure, antihyperglycaemia and lipid‐lowering therapy. Most patients reported psychological (84.5%) and educational (82.1%) barriers to care, with few perceiving physical barriers to care.

Conclusion:  Living in a rural area with predominantly GP care can be associated with comparatively good metabolic control, although psycho‐educational barriers are frequently present. In the wider community, risk factors for diabetes remain common, and the majority have been screened for components of the metabolic syndrome in the previous year.
Improving access to and outcomes from mental health care in rural Australia
Authors: Morley Belinda , Pirkis Jane , Naccarella Lucio , Kohn Fay , Blashki Grant , Burgess Philip
Published: September 2007

Objective:  Rural Australians face particular difficulties in accessing mental health care. This paper explores whether 51 rural Access to Allied Psychological Services projects, funded under the Better Outcomes in Mental Health Care program, are improving such access, and, if so, whether this is translating to positive consumer outcomes.

Design and method:  The paper draws on three data sources (a survey of models of service delivery, a minimum dataset and three case studies) to examine the operation and achievements of these projects, and makes comparisons with their 57 urban equivalents as relevant.

Results:  Proportionally, uptake of the projects in rural areas has been higher than in urban areas: more GPs and allied health professionals are involved, and more consumers have received care. There is also evidence that the models of service delivery used in these projects have specifically been designed to resolve issues particular to rural areas, such as difficulties recruiting and retaining providers. The projects are being delivered at no or low cost to consumers, and are achieving positive outcomes as assessed by standardised measures.

Conclusion:  The findings suggest that the rural projects have the potential to improve access to mental health care for rural residents with depression and anxiety, by enabling GPs to refer them to allied health professionals. The findings are discussed with reference to recent reforms to mental health care delivery in Australia.
Self‐reported confidence and skills of general practitioners in management of mental health disorders
Authors: Browne Mark Oakley , Lee Adeline , Prabhu Radha
Published: September 2007

Objective:  To identify the predictors of self‐reported confidence and skills of GPs in management of patients with mental health problems.

Design:  Cross‐sectional survey, with questionnaire presented to 246 GPs working in 62 practices throughout Gippsland.

Setting:  Rural general practices in Gippsland.

Participants:  One hundred and thirty‐four GPs across Gippsland.

Main outcome measures:  GPs completed a questionnaire assessing self‐perception of knowledge and skills in recognition and management of common mental health problems.

Results:  Of 134 GPs, 45% reported that they have a specific interest in mental health, and 39% of GPs reported that they had previous mental health training. Only 22% of GPs describe having both an interest and prior training in mental health care. Age and years since graduation are not significantly related to self‐reported confidence and skills.

Conclusions:  The results of this study highlight that self‐professed interest and prior training in mental health are associated. Self‐professed interest in mental health care predicts confidence and self‐perceived skills in recognition, assessment and management of common mental health disorders. Similarly, prior training in mental health care predicts confidence and self‐perceived skills in recognition, assessment and management of common mental health problems. Self‐professed interest in mental health issues is also associated with hours of participation in continuing medical education related to mental health care. Unfortunately, only a minority described having both interest and prior training in mental health care.
Where is the evidence that rural exposure increases uptake of rural medical practice?
Authors: Ranmuthugala Geetha , Humphreys John , Solarsh Barbara , Walters Lucie , Worley Paul , Wakerman John , Dunbar James A. , Solarsh Geoff
Published: September 2007

Australian Government initiatives to address medical workforce shortages in rural Australia include increasing the intake of students of rural background and increasing exposure to rural medicine during training. Rural‐orientated medical training programs in the USA that selectively admit students from rural backgrounds and who intend to practise as family practitioners have demonstrated success in increasing uptake of practice in rural/underserved areas. However, in examining the specific contribution of rural exposure towards increasing uptake of rural practice, the evidence is inconclusive, largely due to the failure to adjust for these critical independent predictors of rural practice. This paper identifies this evidence gap, examines the concept of rural exposure, and highlights the need to identify which aspects of rural exposure contribute to a positive attitude towards rural practice, thereby influencing students to return to rural areas. The cost of rural exposure through student placements is not insignificant, and there is a need to identify which aspects are most effective in increasing the uptake of rural practice, thereby helping to address the medical workforce shortage experienced in rural Australia.
Supporting an emerging workforce: Characteristics of rural and remote therapy assistants in Western Australia
Authors: Lin Ivan , Goodale Belinda , Villanueva Karen , Spitz Suzanne
Published: September 2007

Objective:  Multidisciplinary therapy assistants (TAs) are an emerging but poorly understood rural and remote allied health workforce. As an aid to planning and support of TA programs in rural and remote Western Australia (WA), the number, locality and a range of practice variables of rural and remote TAs in WA were determined.

Design:  Survey questionnaire.

Setting:  Rural and remote regions of WA.

Participants:  Allied health professionals, TAs, TA coordinators and managers of allied health in country regions of WA.

Main outcome measures:  Information was gathered on TA location, qualifications, employing organisation, allied health disciplines TAs work with, supervision practices, role and work scenarios.

Results:  Ninety‐eight TAs were identified in rural and remote WA with a further 23 vacant TA positions. Most TAs work across multiple allied health disciplines, half are located at a distance to their supervisors, and very few have a recognised qualification for their TA work.

Conclusion:  A substantial rural and remote TA workforce was found. A range of TA characteristics were identified that have considerable relevance to the future planning of TA initiatives in rural and remote WA.
Proposal of Pseudochattonella verruculosa gen. nov., comb. nov. (Dictyochophyceae) for a formar raphidophycean alga Chattonella verruculosa, based on 18S rDNA phylogeny and ultrastructural characteristics
Authors: Hosoi‐Tanabe Shoko , Honda Daiske , Fukaya Sachiko , Otake Isamu , Inagaki Yuji , Sako Yoshihiko
Published: September 2007

Chattonella verruculosa Y. Hara et Chihara was re‐examined by molecular methods and microscopic examination. The 18S rDNA phylogenetic analysis clearly indicated that C. verruculosa is a member of the Dictyochophyceae, with a specific affinity to Florenciella parvula. The morphological features in C. verruculosa– namely the proximal helix with two gyres and many scattered DNA‐containing areas in the chloroplasts – display the evolutionary link to the Dictyochophyceae, instead of the Raphidophyceae. Similarly, unique pyrenoid morphologies are shared between C. verruculosa and the dictyochophycean algae. Combining the molecular data and morphological characteristics, C. verruculosa is transferred to Pseudochattonella gen. nov. of the class Dictyochophyceae as Pseudochattonella verruculosa (Y. Hara et Chihara) Hosoi‐Tanabe, Honda, Fukaya, Inagaki et Sako comb. nov.
Cladosiphon umezakiisp. nov. (Ectocarpales, Phaeophyceae) from Japan
Authors: Ajisaka Tetsuro , Kim Sung‐Ho , Uwai Shinya , Kawai Hiroshi
Published: September 2007

The new speciesCladosiphon umezakiiAjisaka (Ectocarpales, Phaeophyceae) is described from Japan based on morphology and DNA sequences. The species resemblesCladosiphon okamuranusTokida in its gross morphology; somewhat slimy, cylindrical, multiaxial and sympodial erect thallus, arising from a small disc‐shaped holdfast, and branching once to twice. However,C. umezakiihas considerably longer assimilatory filaments (up to 840 μm long, composed of up to 90 cells) than any known taxa of the genus. The species is a winter to spring annual, growing on lower intertidal to subtidal rocks of more or less exposed sites on the north‐eastern coast of Kyushu and on both the Pacific and the Sea of Japan coasts of Honshu. Specimens from the Sea of Japan coast had both unilocular and plurilocular zoidangia, whereas those from Kyushu and from the Pacific had only unilocular zoidangia. Unilocular zoidangia were formed on the basal part of assimilatory filaments, and plurilocular ones were transformed from the distal part of assimilatory filaments. DNA sequences of the Rubisco‐spacer (rbc‐spacer) region and the nuclear rDNA ITS region (ITS1, 5.8S and ITS2) supported the distinctness of the species.
Re‐examination of ultrastructures of the stellate chloroplast organization in brown algae: Structure and development of pyrenoids
Authors: Tanaka Atsuko , Nagasato Chikako , Uwai Shinya , Motomura Taizo , Kawai Hiroshi
Published: September 2007

Some taxa of brown algae have a so‐called ‘stellate’ chloroplast arrangement composed of multiple chloroplasts arranged in a stellate configuration, or else a single chloroplast with radiating lobes. The fine structures of chloroplasts and pyrenoids have been studied, but the details of their membrane configurations as well as pyrenoid ontogeny have not been well understood. The ultrastructure of the single stellate chloroplast in Splachnidium rugosum and Scytothamnus australis were re‐examined in the present study, as well as the stellate arrangement of chloroplasts in Asteronema ferruginea and Asterocladon interjectum, using freeze‐substitution fixation. It was confirmed that the chloroplast envelope invaginated into the pyrenoid in Splachnidium rugosum, Scytothamnus australis and Asteronema ferruginea, but chloroplast endoplasmic reticulum (CER) remained on the surface of the chloroplast. The space between the invaginated chloroplast envelope and CER was filled with electron‐dense material. In Asteronema ferruginea, CER surrounding each pyrenoid was closely appressed to the neighboring CER over the pyrenoids, so that the chloroplasts formed a stellate configuration; however, in the apical cells chloroplasts formed two or more loose groups, or were completely dispersed. The pyrenoids of Asterocladon interjectum did not have any invagination of the chloroplast envelope, but a unique membranous sac surrounded the pyrenoid complex and occasionally other organelles (e.g. mitochondria). Immunolocalization of β‐1,3‐glucans showed that the membranous sac in Asterocladon interjectum did not contain photosynthetic products such as chrysolaminaran. Observations in the dividing cells of Splachnidium rugosum and Scytothamnus australis indicated that the pyrenoid in the center of the chloroplast enlarged and divided into two before or during chloroplast division.
Variation in metal concentrations in the brown alga Undaria pinnatifida in Osaka Bay, Japan
Authors: Yamada Mika , Yamamoto Koshi , Ushihara Yasuhiro , Kawai Hiroshi
Published: September 2007

In order to evaluate the usefulness of a biomonitoring system using seaweeds for assessing the geographic distribution of metal ions in coastal seawaters, the metal concentrations in the sporophytes of an annual kelp, Undaria pinnatifida (Harvey) Suringar, were collected at 15 localities in Osaka Bay, Japan and compared. About 160 cm2 of the blade was cut out from the central part of clean sporophytes, rinsed in filtered seawater using an ultrasonic cleaning bath, and freeze‐dried. After digestion with 12% HNO3 in a microwave apparatus, metal concentrations in the samples were determined by inductively coupled plasma mass spectrometry. The concentrations (dry weight basis) of most examined elements were in the parts per million range; Cr, 0.48–3.18; Ni, 0.77–5.94; Cu, 3.20–43.8; Zn, 11.3–86.8; Pb, 0.14–3.53. Comparisons of metal compositions of the U. pinnatifida samples from the northeastern area of the bay, which has a large urban population and highly developed industries inland, showed high concentrations of Cd, Pb and Cu compared with the samples from the southwestern area of the bay where the population and industries are much smaller. This suggests that U. pinnatifida metal loads can be used as a marker to track the geographic distributions of the metal concentrations in coastal seawaters, reflecting inland human activities such as shipbuilding and repairing in port areas, and can be used as a useful biomonitoring system of coastal environments for long‐term trend.
Cochlodinium fulvescens sp. nov. (Gymnodiniales, Dinophyceae), a new chain‐forming unarmored dinoflagellate from Asian coasts
Authors: Iwataki Mitsunori , Kawami Hisae , Matsuoka Kazumi
Published: September 2007

Cellular morphology and the phylogenetic position of a new unarmored photosynthetic dinoflagellate Cochlodinium fulvescens Iwataki, Kawami et Matsuoka sp. nov. were examined by light microscopy and molecular phylogenetic analyses based on partial large subunit ribosomal DNA (LSU rDNA) and small subunit ribosomal DNA (SSU rDNA) sequences. The cells of C. fulvescens closely resemble C. polykrikoides, one of the most harmful red tide forming dinoflagellates, due to it possessing a cingulum encircling the cell approximately twice, a spherical nucleus positioned in the anterior part of the cell and an eyespot‐like orange pigmented body located in the dorsal side of the epicone, as well as formation of cell‐chains. However, this species is clearly distinguished from C. polykrikoides based on several morphological characteristics, namely, cell size, shape of chloroplasts and the position of narrow sulcus situated in the cell surface. The sulcus of C. fulvescens is located at the intermediate position of the cingulum in the dorsal side, whereas that of C. polykrikoides is situated immediately beneath the cingulum. LSU rDNA phylogenies indicated that C. fulvescens is clearly distinct from, but closely related to C. polykrikoides among dinoflagellates.
Halichrysis corallinarius sp. nov. (Rhodymeniaceae, Rhodophyta) from Puerto Rico, Caribbean Sea
Authors: Ballantine David L. , Saunders Gary W. , Ruiz Hector
Published: September 2007

A new species, Halichrysis corallinarius sp. nov. is described from coral reef habitats in southwest Puerto Rico as well as from Grand Cayman Island. The new species produces strap‐shaped thalli supported above the substrata by abundant peg‐like stipes. The lobed branches are frequently anastomosed with colonies measuring to 4.0 cm broad with individual axes measuring to 7.0 mm across. Algae possess up to five layers of medullary cells with frequent open spaces in the medulla. Tetrasporangia, measure to 19 × 25 μm, and are borne in sori limited to ventral surfaces. Gametophytes are monoecious and hemispherical carposporophytes are produced dorsally, measuring to 900 μm in diameter and 600 μm high.
Role of Wnt/β‐catenin signaling pathway in epithelial‐mesenchymal transition of human prostate cancer induced by hypoxia‐inducible factor‐1α
Authors: Jiang Yong‐Guang , Luo Yong , He Da‐lin , Li Xiang , Zhang Lin‐lin , Peng Tao , Li Ming‐Chuan , Lin Yun‐Hua
Published: September 2007

Objectives:  Epithelial‐mesenchymal transition (EMT) is an important process in tumor development, and several studies suggest that the Wnt/β‐catenin signal pathway may play an important role in EMT. However, there is no direct evidence showing that the Wnt/β‐catenin pathway actually determines the EMT induced by an exogenous signal. Our previous research has successfully proved that overexpression of hypoxia‐inducible factor‐1α (HIF‐1α) could induce EMT in LNCaP cells, but not in PC‐3. The present study aims to determine whether the signal of HIF‐1α for inducing prostate cancer cells to undergo EMT might possibly pass through the Wnt/β‐catenin pathway.

Methods:  Epithelial‐mesenchymal transition associated proteins were detected in several human prostate carcinoma cell lines by Western blot, and then we distinguished the EMT positive cell lines from the EMT negative cell lines. Furthermore, we evaluated the possible correlation between potency of invasiveness and proliferation among these cell lines with different characteristics of EMT using Matrigel transwell and thiazolyl blue tetrazolium bromide (MTT) assays. Finally, the different expression of some critical proteins and genes in Wnt/β‐catenin signaling pathway were analyzed by Western blot and reverse transcription‐polymerase chain reaction (RT‐PCR) in these cells with different characteristics of EMT.

Results:  Among several prostate cancer cell lines, PC‐3, LNCaP and PC‐3/HIF‐1α are EMT negative cell lines, whereas LNCaP/HIF‐1α and IA8 have undergone the EMT process. EMT positive cells (LNCaP/HIF‐1α and IA8) exhibit much stronger potency of invasiveness and proliferation than those of PC‐3 and LNCaP, which belong to EMT negative cells. Interestingly, although PC‐3/HIF‐1α had not completed the EMT process, it still displayed stronger potency of invasion and proliferation, resembling EMT positive cells. The protein expression level of total glycogensynthase kinase 3β (GSK‐3β) and phospho‐GSK‐3β in LNCaP/HIF‐1α, IA8 and PC‐3/HIF‐1α cells significantly decreased; however, the relative ratios of p‐GSK3β/t‐GSK3β in LNCaP/HIF‐1α, IA8 and PC‐3/HIF‐1α cells were significantly higher than PC‐3 and LNCaP. Consistently, β‐catenin protein expression increased in LNCaP/HIF‐1α and IA8 cells, but not in PC‐3/HIF‐1α; RT‐PCR confirmed these results, except for the enhanced transcription activity of β‐catenin mRNA in PC‐3/HIF‐1α.

Conclusion:  Our data suggests that activation of the Wnt/β‐catenin signaling pathway correlates with the characteristic of EMT and potency of invasiveness and proliferation. This may be the critical factor that directly controls the process of EMT induced by HIF‐1α in prostate cancer cells.
Insulin‐sensitizing antihyperglycaemic medications are associated with better outcome in patients with diabetes undergoing cardiac stress testing
Authors: Kapinya K. , Nijjar P. S. , Stanek M. , Amanullah A.
Published: September 2007

Background:  There are several treatment modalities available for diabetes; however, the effects of the different medications on coronary artery disease are less understood. The purpose of this study was to evaluate the correlation of insulin‐sensitizing therapy with the outcome of stress myocardial perfusion testing and to compare it with conventional therapy.

Methods:  Of 417 patients referred to stress testing for evaluation of chest pain, 222 were identified as being treated with conventional therapy only (insulin and insulin secretagogues) and 195 as being treated with insulin sensitizers (metformin and thiazolidinediones (TZD)). Multivariate logistic regression models were used to correct for confounding factors and to determine the independent relation between treatment type and stress‐test outcome.

Results:  Ischaemia, infarction and the composite outcome were less frequent in the insulin‐sensitizer group than in the conventional therapy group (odds ratio (OR) = 0.39, P = 0.025; OR = 0.32, P = 0.021 and OR = 0.38, P = 0.009, respectively). The subgroup analysis showed that treatment with metformin (n = 125) compared with conventional therapy was associated with less infarction or the composite outcome of ischaemia and/or ischaemia (OR = 0.18 (95% confidence interval (CI): 0.05–0.66), P = 0.010; OR = 0.34 (95%CI: 0.15–0.80), P = 0.014, respectively). Treatment with TZD (n = 43) was associated with a trend to less frequent ischaemia (OR = 0.18 (95%CI: 0.03–1.01), P = 0.051).

Conclusion:  The addition of insulin‐sensitizing medications to the conventional diabetes therapy or their sole use was associated with decreased coronary artery disease or its severity in patients with diabetes as determined by stress myocardial perfusion study. Randomized prospective trials will be necessary to prove this benefit.
Endothelial dysfunction in Turkish patients with non‐alcoholic fatty liver disease
Authors: Senturk O. , Kocaman O. , Hulagu S. , Sahin T. , Aygun C. , Konduk T. , Celebi A.
Published: September 2007

Background:  The components of the metabolic syndrome are closely related with endothelial dysfunction, which is a pathophysiological issue of cardiovascular diseases. Non‐alcoholic fatty liver disease (NAFLD) is considered as one of the components of the metabolic syndrome. The aim of this study was to evaluate the endothelial‐dependent dilatation (EDD) and endothelial‐independent dilatation (EID) of the brachial artery in NAFLD.

Methods:  Fifteen non‐alcoholic steatohepatitis (NASH), 17 patients with simple steatosis and 16 healthy subjects formed the study group. Non‐alcoholic fatty liver disease group was composed of patients admitted to the gastroenterology outpatient clinic because of increased liver enzymes. Endothelial functions of the brachial artery were evaluated by vascular ultrasound. EDD was assessed by establishing reactive hyperaemia, and EID was determined by using sublingual nitrate.

Results:  No statistical difference for the basal diameter of brachial artery was found between the groups (P = 0.49). The values for EDD and EID were significantly different across all three groups (P < 0.0001 and P < 0.0001, respectively). EDD and EID were significantly lower in NASH compared with simple steatosis (P = 0.01 and P < 0.01, respectively). However, there was no statistical significance for EDD and EID in simple steatosis groups compared with controls (P = 0.58 and P = 0.98, respectively).

Conclusions:  Our study showed that patients with NASH had significantly worse endothelial dysfunction compared with patients with simple steatosis and healthy subjects. The treatment strategies with ameliorative effects for endothelial dysfunction might be effective for delaying the development of cardiovascular complications in NAFLD.
Surveillance following treatment for colorectal cancer in Australia. Has best practice been adopted by medical oncologists?
Authors: Kosmider S. , Field K. , Jefford M. , Jennens R. , Gibbs P.
Published: September 2007

Background:  Intensive follow up after surgery for colorectal cancer is associated with a significant survival advantage and is endorsed by expert panels, but are physicians convinced of the benefit?

Methods:  A questionnaire was mailed to all members of the Medical Oncology Group of Australia, assessing surveillance practices after completion of adjuvant treatments.

Results:  Responses were obtained from 141 (55%) medical oncologists of which 121 were considered evaluable. Thirteen per cent (n = 16) routinely did not carry out follow‐up investigations. Of those carrying out surveillance, 47% (n = 51) nominated identifying potentially resectable metastatic disease as prime consideration. Many (44%) were motivated by patient reassurance and expectation. Carcinoembryonic antigen levels were commonly monitored 3 monthly in years 1 (77%, n = 85) and 2 (57%, n = 63) and 6 monthly thereafter (67%, n = 74). Eighty per cent (n = 88) carried out computed tomography (CT) surveillance 1 year after surgery, 69% (n = 76) at year 2 and 55% (n = 60) at year 3. Twenty‐six per cent (n = 29) continued scanning annually up to 5 years. Inclusion of CT chest was routine for 33% (n = 36) and never carried out by 11% (n = 12).

Conclusion:  A significant minority (13%) of oncologists carry out no follow‐up investigations, despite level I evidence of a survival advantage similar to standard adjuvant therapies. Further education and study of physician attitudes and reservations to routine surveillance are required.
Estimating fatigue sensitivity to polycrystalline Ni‐base superalloy microstructures using a computational approach
Authors: SHENOY M. , ZHANG J. , McDOWELL D.L.
Published: September 2007

A computational study is conducted to determine the influence of microstructure attributes and properties on driving forces for fatigue crack formation and microstructurally small crack growth in a polycrystalline Ni‐base superalloy, IN100, a turbine disk alloy. A principal objective is to obtain quantitative estimates of the effect of variability of microstructure features on scatter in fatigue life or fatigue strength for a given life. Understanding is sought regarding sensitivity of driving forces to various microstructure attributes that may guide selection of the process route to tailor microstructure to achieve fatigue resistance. A microstructure‐sensitive crystal plasticity model is used to explicitly model individual grains and polycrystals, which is then used to explore effects of: (a) grain size distribution and (b) secondary and tertiary coherent γ′ precipitate size distributions and volume fractions on the cyclic inelastic strain distribution. Multiple statistical volume elements (SVEs) are subjected to random periodic boundary conditions to build up statistically significant measures of distributions of cyclic microplasticity. Multiaxial fatigue criteria with critical plane approaches are used to estimate the crack initiation life. Methods are developed for assessing crack formation and microstructurally small crack growth as a function of microstructure attributes.
GABAergic pathways in the rat subcortical visual system: a comparative study in vivo and in vitro
Authors: Born Gesche , Schmidt Matthias
Published: September 2007

Inhibitory pathways project from the pretectal nuclear complex to the ipsilateral superior colliculus (SC) and dorsal lateral geniculate nucleus (dLGN). Both pathways arise from GABAergic neurones that are located in the dorsal pretectal nuclear complex. In the present experiments, we compared the anatomy and physiology of these two pathways with the objective of determining whether they have similar functions. First, we injected retrograde axonal tracers that fluoresce at different wavelengths in the dLGN and SC of single animals to determine if individual GABAergic neurones in the pretectum project to both structures. The results showed that the dLGN and SC receive input from different cell groups. Next, morphological reconstructions of cells labelled after in‐vitro whole‐cell patch‐clamp recordings demonstrated that the pretectal‐recipient cells in the dLGN are GABAergic interneurones, whereas those in the SC are projection cells. Finally, with in‐vitro whole‐cell patch‐clamp recordings we showed that inhibitory currents generated by both pathways are mediated by GABAA receptors. Taken together, these results suggest that these inhibitory projections may function to facilitate the relay of information from the dLGN to the visual cortex by suppressing the activity of dLGN interneurones, and to reduce the level of activity leaving the SC by inhibiting the projection neurones. These hypotheses will be discussed in the context of the known functions of the pretectal complex.
Modifications of cognitive and motor tasks affect the occurrence of event‐related potentials in the human cortex
Authors: Rektor Ivan , Brázdil Milan , Nestrašil Igor , Bareš Martin , Daniel Pavel
Published: September 2007

This study concerns the question of how task modification affects the frequency occurrence of event‐related potentials (ERP) inside the active cortical areas. In 13 candidates for epilepsy surgery, 156 sites in the temporal (74), frontal (73), and parietal (9) cortices were recorded by means of depth and subdural electrodes. Four modifications of the somatosensory evoked P3‐like potentials were performed; (i) an oddball paradigm with silent counting of target stimuli (P3c); (ii) an oddball paradigm with a hand movement in response to target stimuli (P3m); (iii) an S1–S2 paradigm, ERP in the P300 time window after the S2 stimulus, with silent counting of target stimuli (S2c), and (iv) an S1–S2 paradigm with a hand movement in response to target stimuli (S2m). In comparing the oddball paradigms with the S1–S2 (contingent negative variation, CNV) paradigms, four regions emerge that are significantly linked with the oddball P3; the prefrontal cortex, the cingulate, the amygdalo‐hippocampal complex, and the lateral temporal cortex. A prominent role of the cingulate and the fronto‐orbital cortex in the cognitive processing of movement was supported when tasks with identical cognitive loads but different required responses were compared. Even relatively simple cognitive tasks activate many cortical regions. The investigated areas were activated in all tests; however, small regions in each field were active or inactive in relation to the nature of the task. The study indicates a variable and task‐dependent internal organization of a highly complex and widely distributed system of active cortical areas.
Recovery from spinal cord injury differs between rat strains in a major histocompatibility complex‐independent manner
Authors: Birdsall Abrams M. , Josephson Anna , Dominguez Cecilia , Öberg Johanna , Diez Margarita , Spenger Christian , Olson Lars , Piehl Fredrik , Lidman Olle
Published: September 2007

Inflammation is a common characteristic of spinal cord injury. The nature of this response, whether it is beneficial or detrimental, has been the subject of debate. It has been reported that susceptibility to autoimmunity is correlated with increased functional impairment following spinal cord injury. As the ability to mount an autoimmune response has most consistently been associated with certain haplotypes of the major histocompatibility complex (MHC), we analysed the possible effects of the MHC haplotype on functional impairment and recovery following spinal cord injury. A contusion injury was induced in experimental autoimmune encephalomyelitis‐susceptible and ‐resistant rats [Dark Agouti, Lewis and Piebald Viral Glaxo (PVG), respectively]. We found that locomotion recovered significantly better in Dark Agouti rats compared with PVG and Lewis rats but an F2 intercross (PVG × PVG‐RT1av1) excluded the possibility that this difference was MHC haplotype‐dependent. Thus, we conclude that recovery following spinal cord injury is subject to considerable genetic heterogeneity that is not coupled to the MHC haplotype region. Continued research of genetic variants regulating recovery following spinal cord injury is warranted.
Frontal and temporal functional connections of the living human brain
Authors: Lacruz M. E. , García Seoane J. J. , Valentin A. , Selway R. , Alarcón G.
Published: September 2007

Connections between human temporal and frontal cortices were investigated by intracranial electroencephalographic responses to electrical stimulation with 1‐ms single pulses in 51 patients assessed for surgery for treatment of epilepsy. The areas studied were medial temporal, entorhinal, lateral temporal, medial frontal, lateral frontal and orbital frontal cortices. Findings were assumed to be representative of human brain as no differences were found between epileptogenic and non‐epileptogenic hemispheres. Connections between intralobar temporal and frontal regions were common (43–95%). Connections from temporal to ipsilateral frontal regions were relatively uncommon (seen in 0–25% of hemispheres). Connections from frontal to ipsilateral temporal cortices were more common, particularly from orbital to ipsilateral medial temporal regions (40%). Contralateral temporal connections were rare (< 9%) whereas contralateral frontal connections were frequent and faster, particularly from medial frontal to contralateral medial frontal (61%) and orbital frontal cortices (57%), and between both orbital cortices (67%). Orbital cortex receives profuse connections from the ipsilateral medial (78%) and lateral (88%) frontal cortices, and from the contralateral medial (57%) and orbital (67%) frontal cortices. The high incidence of intralobar temporal connections supports the presence of temporal reverberating circuits. Frontal cortex projects within the lobe and beyond, to ipsilateral and contralateral structures.
Brain imaging of analgesic and antihyperalgesic effects of cyclooxygenase inhibition in an experimental human pain model: a functional MRI study
Authors: Maihöfner Christian , Ringler Ralf , Herrndobler Franz , Koppert Wolfgang
Published: September 2007

One of the most distressing symptoms of many neuropathic pain syndromes is the enhanced pain sensation to tactile or thermal stimulation (hyperalgesia). In the present study we used functional magnetic resonance imaging (fMRI) and explored brain activation patterns during acute impact pain and mechanical hyperalgesia in the human ultraviolet (UV)‐B model. To investigate pharmacological modulation, we examined potential differential fMRI correlates of analgesic and antihyperalgesic effects of two intravenous cyclooxygenase inhibitors, i.e. parecoxib and acetylsalicylic acid (ASA). Fourteen healthy volunteers participated in this double‐blinded, randomized and placebo‐controlled crossover study. Tactile stimuli and mechanical impact hyperalgesia were tested at the site of a UV‐B irradiation and acute mechanical pain was tested at a site distant from the irradiated skin. These measurements were conducted before and 30 min after a 5‐min intravenous infusion of either saline (placebo), parecoxib 40 mg or ASA 1000 mg. Acute mechanical pain and mechanical hyperalgesia led to widespread activations of brain areas known to comprise the human pain matrix. Analgesic effects were found in primary (S1) and secondary (S2) somatosensory cortices, parietal association cortex (PA), insula, anterior parts of the cingulate cortex and prefrontal cortices. These brain areas were also modulated under antihyperalgesic conditions. However, we observed a greater drug‐induced modulation of mainly PA and inferior frontal cortex during mechanical hyperalgesia; during acute mechanical pain there was a greater modulation of mainly bilateral S2. Therefore, the results of the present study suggest that there is a difference in the brain areas modulated by analgesia and antihyperalgesia.
Noise‐improved signal detection in cat primary visual cortex via a well‐balanced stochastic resonance‐like procedure
Authors: Funke Klaus , Kerscher Nicolas J. , Wörgötter Florentin
Published: September 2007

Adding noise to a weak signal can paradoxically improve signal detection, a process called ‘stochastic resonance’ (SR). In the visual system, noise might be introduced by the image jitter resulting from high‐frequency eye movements, like eye microtremor and microsaccades. To test whether this kind of noise might be beneficial or detrimental for cortical signal detection, we performed single‐unit recordings from area 17 of anaesthetized cats while jittering the visual stimulus in a frequency and amplitude range resembling the possible range of eye movements. We used weak, sub‐ and peri‐threshold visual stimuli, on top of which we superimposed noise with variable jitter amplitude. In accordance with the typical SR effect, we found that small noise levels actually increased the signal‐to‐noise ratio (SNR) of previously weak cortical visual responses, while originally strong responses were little affected or even reduced. Above a certain noise level, the SNR dropped a little, but not as a result of increased background activity − as would be proposed by SR theory − but because of a lowered response to signal and noise. Therefore, it seems that the ascending visual pathway optimally utilizes signal detection improvement by a SR‐like process, while at the same time preventing spurious noise‐induced activity and keeping the SNR sufficiently high.
Brain edema and breakdown of the blood–brain barrier during methamphetamine intoxication: critical role of brain hyperthermia
Authors: Kiyatkin Eugene A. , Brown P. Leon , Sharma Hari S.
Published: September 2007

To clarify the role of brain temperature in permeability of the blood–brain barrier (BBB), rats were injected with methamphetamine (METH 9 mg/kg) at normal (23 °C) and warm (29 °C) environmental conditions and internal temperatures were monitored both centrally (nucleus accumbens, NAcc) and peripherally (skin and nonlocomotor muscle). Once NAcc temperatures peaked or reached 41.5 °C (a level suggesting possible lethality), animals were administered Evans blue dye (protein tracer that does not normally cross the BBB), rapidly anaesthetized, perfused and had their brains removed. All METH‐treated animals showed brain and body hyperthermia associated with relative skin hypothermia, suggesting metabolic activation coupled with peripheral vasoconstriction. While METH‐induced NAcc temperature elevation varied from 37.60 to 42.46 °C (or 1.2–5.1 °C above baseline), it was stronger at 29 °C (+4.13 °C) than 23 °C (+2.31 °C). Relative to control, METH‐treated animals had significantly higher brain levels of water, Na+, K+ and Cl–, suggesting brain edema, and intense immunostaining for albumin, indicating breakdown of the BBB. METH‐treated animals also showed strong immunoreactivity for glial fibrillary acidic protein (GFAP), possibly suggesting acute abnormality or damage of astrocytes. METH‐induced changes in brain water, albumin and GFAP correlated linearly with NAcc temperature (r = 0.93, 0.98 and 0.98, respectively), suggesting a key role of brain hyperthermia in BBB permeability, development of brain edema and subsequent functional and structural neural abnormalities. Therefore, along with a direct destructive action on neural cells and functions, brain hyperthermia, via breakdown of the BBB, may be crucial for both decompensation of brain functions and cell injury following acute METH intoxication, possibly contributing to neurodegeneration resulting from chronic drug use.
Antagonism of group III metabotropic glutamate receptors results in impairment of LTD but not LTP in the hippocampal CA1 region, and prevents long‐term spatial memory
Authors: Altinbilek Bengi , Manahan‐Vaughan Denise
Published: September 2007

Recently it has emerged that hippocampal long‐term depression (LTD) may play an important role in the acquisition and storage of spatial memories. This form of synaptic plasticity is tightly regulated by metabotropic glutamate receptors (mGluRs) that negatively couple to adenylyl cyclase. Activation of group III mGluRs is necessary for persistent hippocampal LTD, but is not required for depotentiation or long‐term potentiation (LTP) in the dentate gyrus in vivo. In the CA1 region antagonism of group III mGluRs prevents LTD in vivo. Effects on LTP in vivo are as yet unknown. We investigated the effects of group III mGluR antagonism on LTP and LTD at Schaffer collateral‐CA1 synapses, and on spatial learning in the eight‐arm radial maze. Daily application of the group III mGluR antagonist (R,S)‐α‐cyclopropyl‐4‐phosphonophenylglycine (CPPG) resulted in impairment of long‐term (reference) memory, with effects becoming apparent 4 days after training and drug treatment began. Short‐term (working) memory was unaffected throughout the 10‐day study. Application of CPPG prevented LTD, but not LTP, in the CA1 region. These data suggest that activation of group III mGluRs is required for the establishment of spatial long‐term memory. Their exclusive role in mediating hippocampal LTD provides correlational evidence for a role for LTD in the type of spatial learning studied.
Hydroxy‐α‐sanshool activates TRPV1 and TRPA1 in sensory neurons
Authors: Koo Jae Yeon , Jang Yongwoo , Cho Hawon , Lee Chang‐Hun , Jang Kyoung Hwa , Chang Yong Ha , Shin Jongheon , Oh Uhtaek
Published: September 2007

Sanshools are major active ingredients of Zanthoxylum piperitum and are used as food additives in East Asia. Sanshools cause irritant, tingling and sometimes paresthetic sensations on the tongue. However, the molecular mechanism underlying the pungent or tingling sensation induced by sanshools is not known. Because many transient receptor potential (TRP) channels are responsible for the sensations induced by various spices and food additives, we expressed 17 TRP channels in human embryonic kidney (HEK) cells and investigated their activation by hydroxy‐α‐sanshool (HαSS) or hydroxy‐β‐sanshool (HβSS) isolated from Zanthoxylum piperitum. It was found that HαSS, but not HβSS, depolarized sensory neurons with concomitant firing of action potentials and evoked inward currents. Among 17 TRP channels expressed in HEK cells, HαSS caused Ca2+ influx in cells transfected with TRPV1 or TRPA1, and evoked robust inward currents in cells transfected with TRPV1 or TRPA1. In primary cultured sensory neurons, HαSS induced inward currents and Ca2+ influx in a capsazepine‐dependent manner. Moreover, HαSS‐induced currents and Ca2+ influx were greatly diminished in TRPV1–/– mice. HαSS evoked licking behavior when injected into a single hind paw of wild‐type mice, but this was much reduced in TRPV1‐deficient mice. These results indicate that TRPV1 and TRPA1 are molecular targets of HαSS in sensory neurons. We conclude that the activations of TRPV1 and TRPA1 by HαSS explain its unique pungent, tingling sensation.
Divergent co‐transmitter actions underlie motor pattern activation by a modulatory projection neuron
Authors: Stein Wolfgang , DeLong Nicholas D. , Wood Debra E. , Nusbaum Michael P.
Published: September 2007

Co‐transmission is a common means of neuronal communication, but its consequences for neuronal signaling within a defined neuronal circuit remain unknown in most systems. We are addressing this issue in the crab stomatogastric nervous system by characterizing how the identified modulatory commissural neuron (MCN)1 uses its co‐transmitters to activate the gastric mill (chewing) rhythm in the stomatogastric ganglion (STG). MCN1 contains γ‐aminobutyric acid (GABA) plus the peptides proctolin and Cancer borealis tachykinin‐related peptide Ia (CabTRP Ia), which it co‐releases during the retractor phase of the gastric mill rhythm to influence both retractor and protractor neurons. By focally applying each MCN1 co‐transmitter and pharmacologically manipulating each co‐transmitter action during MCN1 stimulation, we found that MCN1 has divergent co‐transmitter actions on the gastric mill central pattern generator (CPG), which includes the neurons lateral gastric (LG) and interneuron 1 (Int1), plus the STG terminals of MCN1 (MCN1STG). MCN1 used only CabTRP Ia to influence LG, while it used only GABA to influence Int1 and the contralateral MCN1STG. These MCN1 actions caused a slow excitation of LG, a fast excitation of Int1 and a fast inhibition of MCN1STG. MCN1‐released proctolin had no direct influence on the gastric mill CPG, although it likely indirectly regulates this CPG via its influence on the pyloric rhythm. MCN1 appeared to have no ionotropic actions on the gastric mill follower motor neurons, but it did use proctolin and/or CabTRP Ia to excite them. Thus, a modulatory projection neuron can elicit rhythmic motor activity by using distinct co‐transmitters, with different time courses of action, to simultaneously influence different CPG neurons.
GABAergic projections from the hippocampus to the retrosplenial cortex in the rat
Authors: Miyashita Toshio , Rockland Kathleen S.
Published: September 2007

The retrosplenial cortex (RS) in rats has been implicated in a wide range of behaviors, including spatial navigation and memory. Relevant to this, the RS is closely interconnected with the hippocampus by multiple direct and indirect routes. Here, by injecting the retrograde tracer cholera toxin subunit B conjugated with Alexa488 (CTB‐Alexa488) in the granular retrosplenial cortex (GRS), we demonstrate a moderately dense non‐pyramidal projection from CA1. Neurons are in several layers, but mainly (about 65%) at the border of the stratum radiatum (SR) and stratum lacunosum moleculare (SLM). In particular, by double‐labeling with GAD67 or γ‐aminobutyric acid (GABA), we establish that these neurons are GABAergic. Further immunocytochemical screening for calcium‐binding proteins, somatostatin (SS) or cholecystokinin (CCK) failed to identify additional neurochemical subgroups; but a small subset (about 14%) is positive for the m2 muscarinic acetylcholine receptor (M2R). Terminations target layer 1 of the GRS, as shown by biotinylated dextran amine (BDA) injections into CA1 and confirmed by a very superficial injection of CTB‐Alexa488 in GRS. The superficial injection shows that there is a sparse GABAergic projection from the subiculum to layer 1 of the GRS, in addition to the dense excitatory connections to layer 3. The role of these dual inhibitory–excitatory pathways − within the subiculum, and in parallel from CA1 and the subiculum − remains to be determined, but may be related to synchronized oscillatory activity in the hippocampal complex and GRS, or to the generation of rhythmic activity within the GRS.