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PubMed2002

A comparison of female and male rats' ETOH-induced ataxia and exploration following restraint or swim stress.

Animal models of stress reactivity are often employed in developing treatments for humans. Many studies use shock stress, and most use male rats. These experiments compare female and male rats exposed to either restraint stress (RS) or ambient-temperature swim stress (SS), using two durations of each stressor and naive controls. The ataxic effects of a 0.6 g/kg i.p. dose of ethanol (ETOH) were measured. Females exhibited less ataxia than males following ETOH administration. There were no significant effects of stress on ETOH-induced ataxia. Exploration was also measured in an open-field test (OFT) both pre- and poststress. In the prestress OFT, females were more active than males. For the no-stress groups and the shorter-duration stress groups, exploration decreased between the first and second OFTs. However, the groups exposed to the longer-duration stress did not show this expected decrease in exploration. A key finding of this research is that while sex differences may be present at baseline, the sexes may react similarly to stress. These data extend knowledge on sex differences in stress, alcohol reactivity and exploratory behavior.

Animals↗

PubMedDate not supplied

Mars scientific investigations as a precursor for human exploration.

In the past two years, NASA has begun to develop and implement plans for investigations on robotic Mars missions which are focused toward returning data critical for planning human missions to Mars. The Mars Surveyor Program 2001 Orbiter and Lander missions will mark the first time that experiments dedicated to preparation for human exploration will be carried out. Investigations on these missions and future missions range from characterization of the physical and chemical environment of Mars, to predicting the response of biology to the Mars environment. Planning for such missions must take into account existing data from previous Mars missions which were not necessarily focused on human exploration preparation. At the same time, plans for near term missions by the international community must be considered to avoid duplication of effort. This paper reviews data requirements for human exploration and applicability of existing data. It will also describe current plans for investigations and place them within the context of related international activities.

Climate↗

PubMed2003

International Academy of Astronautics 5th cosmic study--preparing for a 21st century program of integrated, Lunar and Martian exploration and development (executive summary).

This report is an initial review of plans for a extensive program to survey and develop the Moon and to explore the planet Mars during the 21st century. It presents current typical plans for separate, associated and fully integrated programs of Lunar and Martian research, exploration and development, and concludes that detailed integrated plans must be prepared and be subject to formal criticism. Before responsible politicians approve a new thrust into space they will demand attractive, defensible, and detailed proposals that explain the WHEN, HOW and WHY of each stage of an expanded program of 21st century space research, development and exploration. In particular, the claims of daring, innovative, but untried systems must be compared with the known performance of existing technologies. The time has come to supersede the present haphazard approach to strategic space studies with a formal international structure to plan for future advanced space missions under the aegis of the world's national space agencies, and supported by governments and the corporate sector.

Cost-Benefit Analysis↗

PubMedDate not supplied

Innovations in mission architectures for exploration beyond low Earth orbit.

Through the application of advanced technologies and mission concepts, architectures for missions beyond Earth orbit have been dramatically simplified. These concepts enable a stepping stone approach to science driven; technology enabled human and robotic exploration. Numbers and masses of vehicles required are greatly reduced, yet the pursuit of a broader range of science objectives is enabled. The scope of human missions considered range from the assembly and maintenance of large aperture telescopes for emplacement at the Sun-Earth libration point L2, to human missions to asteroids, the moon and Mars. The vehicle designs are developed for proof of concept, to validate mission approaches and understand the value of new technologies. The stepping stone approach employs an incremental buildup of capabilities, which allows for future decision points on exploration objectives. It enables testing of technologies to achieve greater reliability and understanding of costs for the next steps in exploration.

Astronomy↗

PubMed1998

Effects of amygdaloid lesions, hippocampal lesions, and buspirone on black-white exploration and food carrying in rats.

Unlesioned rats exploring a black-white two compartment box spent most of the time in the covered, black half of the box and only little time in the uncovered, white half (67 s/5 min). Large radio-frequency lesions of the amygdala or hippocampus did not alter this pattern of exploration, but rats with hippocampus lesions were more active than the other two groups of rats. Treatment with the 5-HT1A receptor agonist buspirone (0.1 mg/kg, s.c.) increased the time that unlesioned rats spent in the uncovered compartment (103 s), an effect that was less pronounced in hippocampus-lesioned rats and completely abolished by amygdala lesions. In a food transport test, unlesioned rats that traveled from a home cage to an exposed food source consumed small and medium-sized pellets immediately at the food source. Larger pellets, however, were carried back to the home cage for consumption. Rats with amygdala lesions ate fewer pellets at the food source and tended to carry more pellets back to the home cage for consumption than unlesioned rats. Rats with hippocampus lesions carried fewer pellets back to the home cage and ate more pellets at the food source. Buspirone (0.5-1.5 mg/kg, s.c.) reduced the carrying of large food items to the home cage and increased consumption of these pellets at the food source in all groups of rats. These results suggest that neither the amygdala nor the hippocampus play an important role in controlling exploratory behavior in a black-white compartment box, but that the amygdala may have some role in mediating the effect of buspirone to increase exploration of the white/open compartment. Further, the amygdala and hippocampus have opposing influences on the transport of food items to a shelter, the amygdala suppressing food carrying, and the hippocampus enhancing it. Neither structure is essential for the effect of buspirone to reduce food carrying. The hypothesis that limbic structures mediate 'fear/anxiety' responses is discussed critically.

Acoustic Stimulation↗

PubMed2003

An exploration of tutors' experiences of facilitating problem-based learning. Part 1--an educational research methodology combining innovation and philosophical tradition.

The use of problem-based learning (PBL) in Health Professional curricula is becoming more wide spread. Although the way in which the tutor facilitates PBL can have a major impact on students' learning (Andrews and Jones 1996), the literature provides little consistency as to how the tutor can effectively facilitate PBL (Haith-Cooper 2000). It is therefore important to examine the facilitation role to promote effective learning through the use of PBL. This article is the first of two parts exploring a study that was undertaken to investigate tutors' experiences of facilitating PBL. This part focuses on the methodology and the combining of innovative processes with traditional philosophical traditions to develop a systematic educational research methodology. The study was undertaken respecting the philosophy of hermeneutic phenomenology but utilised alternative data collection and analysis technique. Video conferencing and e-mail were used in conjunction with more traditional processes to access a worldwide sample. This paper explores some of the issues that arose when undertaking such a study. The second article then focuses on exploring the findings of the study and their implications for the facilitation of PBL.

Attitude of Health Personnel↗

PubMed1995

Exobiological exploration of Mars.

Of all the other planets in the solar system, Mars remains the most promising for further elucidating concepts about chemical evolution and the origin of life. Strategies were developed to pursue three exobiological objectives for Mars exploration: determining the abundance and distribution of the biogenic elements and organic compounds, detecting evidence of an ancient biota on Mars, and determining whether indigenous organisms exist anywhere on the planet. The three strategies are quite similar and, in fact, share the same sequence of phases. In the first phase, each requires global reconnaissance and remote sensing by orbiters to select sites of interest for detailed in situ analyses. In the second phase, lander missions are conducted to characterize the chemical and physical properties of the selected sites. The third phase involves conducting "critical" experiments at sites whose properties make them particularly attractive for exobiology. These critical experiments would include, for example, identification of organics, detection of fossils, and detection of extant life. The fourth phase is the detailed analysis of samples returned from these sites in Earth-based laboratories to confirm and extend previous discoveries. Finally, in the fifth phase, human exploration is needed to establish the geological settings for the earlier findings or to discover and explore sites that are not accessible to robotic spacecraft.

Evolution, Chemical↗

PubMed1994

[Rapid surgical exploration of the mediastinum].

This study aimed to evaluate the morbidity-mortality of surgical exploration of the mediastinum in patients with mediastinal masses or adenopathy in the context of a rapid-surgery program that has been operating over the past 8 years (1985-1993). A total of 93 mediastinal explorations have been carried out. Sixty-five involved transcervical mediastinoscopy, 20 were anterior mediastinotomies, 4 were combined procedures and 4 were video-thoracoscopies. We found 34 cases of lymphoma, 28 of metastasis of bronchopulmonary carcinoma and 16 of mediastinal-ganglionic tuberculosis; the 15 remaining cases were classified as miscellaneous. No deaths were directly related to the surgical procedures; morbidity involved 2 wound infections. Surgical exploration of the mediastinum is a safe diagnostic procedure, provided it is carried out by an experienced team, and allows care givers to take better advantage of therapeutic options with no loss of quality.

Adolescent↗

PubMed2003

The anxiogenic beta-carboline FG-7142 inhibits locomotor exploration similarly in postweanling and adult rats.

The beta-carboline FG-7142 exerts many stress-like effects in the adult rat, including the inhibition of locomotor exploration. However, comparable effects in immature animals have not been reported. Stress-like effects of FG-7142 are mediated via its inverse agonist actions on gamma-aminobutyric acid (GABA) receptors. GABA systems change considerably with development and GABA agonists such as diazepam have opposite behavioral actions in immature and adult rats. Accordingly, we compared FG-7142 effects on locomotor exploration in postweanling and adult rats. Postweanling male rats (24 days) and adult rats (90 days) received a single injection of vehicle or FG-7142 (15 mg/kg i.p.) and 15 min later were placed in photocell monitors for 1 h. Although postweanling animals traveled a smaller distance overall than adults, FG-7142 inhibited locomotor exploration to a similar degree in both groups. We conclude that FG-7142 exerts stress-like effects in postweanling rats and may be considered for use as a model of childhood stress.

Age Factors↗

PubMed1998

Retained glass foreign bodies in wounds: predictive value of wound characteristics, patient perception, and wound exploration.

A convenience sample of 164 adult patients with 185 glass-caused wounds who presented to an emergency department (ED) and consented to a radiograph was prospectively studied. The purpose was to determine the characteristics of wounds at high risk for foreign body (FB) and the predictive value of patient FB sensation and probing wound exploration for FB retention. Retained glass was located in 28 (15%) wounds. Motor vehicle as a mechanism of injury (P=.003), head as a location (P=.035), and puncture as wound type (P=.002) were more likely to be associated with retained FBs (chi2 analysis). Patients with wounds with glass were more likely to have a positive perception of a foreign body (41%) than those with no glass (17%) (P=.005). The positive predictive value of patient perception was 31%; negative predictive value was 89%. In five cases, wound exploration was negative and subsequent radiograph was positive for FB. In one of these cases, a 4-mm glass FB was removed; in the other four, no FB was found. In conclusion, head wounds resulting from motor vehicle accidents or puncture wounds are more likely to harbor retained glass FBs. Patients with glass FB in wounds are more likely to have a positive perception of FB; however, a positive perception has a low predictive value of glass FB. In this series, a negative wound exploration made the presence of retained FB greater than 2 mm less likely but did not rule out the presence of retained glass.

Adult↗

PubMed2003

Using combined research methods for exploring diabetes patient education.

This paper explores a trial of an educational intervention designed for people who have Type 2 diabetes. The aim of the trial was to understand how the intervention had influenced outcomes in the context of participants' everyday lives. A randomised-controlled wait-list trial design was used. The study was also informed by a qualitative approach which explored the meanings held by participants for informing their behaviours. Outcomes were measured using diabetes-specific questionnaires and clinical measures of blood glucose control, weight and drug treatment. Alongside these, focus group discussions were held to explore how outcome effects had transpired. Using these different methods resulted in two separate data sets which required diverse methods for analysis. This paper uses examples of compatibilities and contradictions between the data sets to look at how they were combined to produce valid results. Conclusions drawn showed that a combined methods approach was essential to expand the scope and improve the analytic power of trials of patient education. It produced illuminating results which provided guidelines for practice and suggested further areas for research.

Diabetes Mellitus, Type 2↗

PubMedDate not supplied

Control of exploitation-exploration meta-parameter in reinforcement learning.

In reinforcement learning (RL), the duality between exploitation and exploration has long been an important issue. This paper presents a new method that controls the balance between exploitation and exploration. Our learning scheme is based on model-based RL, in which the Bayes inference with forgetting effect estimates the state-transition probability of the environment. The balance parameter, which corresponds to the randomness in action selection, is controlled based on variation of action results and perception of environmental change. When applied to maze tasks, our method successfully obtains good controls by adapting to environmental changes. Recently, Usher et al. [Science 283 (1999) 549] has suggested that noradrenergic neurons in the locus coeruleus may control the exploitation-exploration balance in a real brain and that the balance may correspond to the level of animal's selective attention. According to this scenario, we also discuss a possible implementation in the brain.

Animals↗

PubMed1990

Brachial artery damage following cardiac catheterisation. When to re-explore.

Cardiac catheterisation is frequently performed in modern medical practice and the brachial artery is frequently used. The brachial and forearm systolic pressures were measured by Doppler ultrasound at rest and after hand exercise for 60 s in 75 patients undergoing catheterisation. These objective measurements, together with a history of forearm claudication during the one minute of exercise and clinical examination of the radial pulse were repeated again at 1 hour, 1 week and 3 months. Changes in the forearm/brachial pressure index (PI) at rest and a fall in forearm pressure after exercise were compared with the pre-catheterisation values. Sixteen per cent of patients suffered claudication of the forearm during the one minute hand exercise immediately after catheterisation. Of those seen at 3 months, 12% had persistent claudication and all had a markedly reduced PI measured following catheterisation. Conversely, at 1 [corrected] hour after catheterisation, the radial pulse was weak or absent in 20% and 33% were abnormal on Doppler studies and not all had symptoms. It emerges that to avoid claudicating forearms at 3 months, re-exploration, one hour after brachial catheterisation is indicated in some cases. We are inclined to base this upon the 16% who had forearm claudication after one minute of exercise and who also had absent or reduced radial [corrected] pulse and abnormal Doppler studies. Conversely to base the need for re-exploration upon a reduction or absence of the radial pulse [corrected] (20%) on Doppler studies (33%) would lead to an unnecessarily high rate of re-exploration just after the procedure.

Arterial Occlusive Diseases↗

PubMed2003

Diagnosis and exploration of massively univariate neuroimaging models.

The goal of this work is to establish the validity of neuroimaging models and inferences through diagnosis and exploratory data analysis. While model diagnosis and exploration are integral parts of any statistical modeling enterprise, these aspects have been mostly neglected in functional neuroimaging. We present methods that make diagnosis and exploration of neuroimaging data feasible. We use three- and one-dimensional summaries that characterize the model fit and the four-dimensional residuals. The statistical tools are diagnostic summary statistics with tractable null distributions and the dynamic graphical tools which allow the exploration of multiple summaries in both spatial and temporal/interscan aspects, with the ability to quickly jump to spatiotemporal detail. We apply our methods to a fMRI data set, demonstrating their ability to localize subtle artifacts and to discover systematic experimental variation not captured by the model.

Algorithms↗

PubMedDate not supplied

Transcystic common bile duct exploration in the management of patients with choledocholithiasis.

Common bile duct stones are found in approximately 16% of patients undergoing laparoscopic cholecystectomy. If the diagnosis of choledocholithiasis is made at the preoperative workup, it is common practice to refer the patient for endoscopic retrograde cholangiography and endoscopic sphincterotomy. However, if the diagnosis is established during intraoperative cholangiography, the surgeon is confronted with a therapeutic dilemma-that is, the choice between laparoscopic common bile duct exploration, conversion to open surgery, or postoperative endoscopic sphincterotomy. We have opted to treat patients with choledocholithiasis in only one session during the laparoscopic cholecystectomy; we use the transcystic common bile duct exploration technique employing the choledochoscope. We report our early experience in terms of success of stone removal, operative time, morbidity and mortality, and length of hospital stay. From 1992 to 2002, we performed 350 laparoscopic cholecystectomies. Selective cholangiography was used in 105 patients (30%); 40 of them were found to have common bile duct stones, for an incidence of 11.4%. Among this group, we performed laparoscopic transcystic common bile duct exploration in all but six patients. Our success rate for stone removal was 94.1% (32 of 34 patients), with only two failures related to multiple stones and impaction at the ampulla, for a conversion rate of 5.8%. The mean operative time was 120+/-40 minutes. The morbidity rate was 8.8%, and there were no deaths. Length of hospital stay was 24 to 48 hours. Mean recovery time was 7 days, and time to return to work was 15+/-3 days. We concluded that most of the patients with common bile duct stones found during laparoscopic cholecystectomy could be treated successfully by means of the transcystic technique with choledochoscopy, with no increase in morbidity or mortality and a shortened hospital stay and recovery time, similar to patients who undergo only laparoscopic cholecystectomy. On the basis of our results, we recommend that this method become the primary strategy in the great majority of patients with common bile duct stones found during intraoperative cholangiography.

Adolescent↗

PubMed2003

Therapeutic landscapes and First Nations peoples: an exploration of culture, health and place.

This paper contributes to an expanding body of research within Health Geography that focuses on the role of therapeutic landscapes in shaping health. Therapeutic landscapes demonstrate the importance of places for maintaining physical, emotional, mental and spiritual health. Meanings of place and the relationship between place and health have culturally specific dimensions, yet these tend to be overlooked especially with respect to First Nations peoples. This paper broadens the analysis of therapeutic landscapes by exploring their culturally specific dimensions in the context of the everyday lives of 'Anishinabek' and thus contributes to a better understanding of First Nations peoples. First Nations peoples contend that the relationship they have with the land shapes the cultural, spiritual, emotional, physical and social lives of individuals and communities. While geographic research has explored First Nations peoples health, few studies have attempted to explore the influence of cultural beliefs and values on health-let alone the intricate link between the land and health. This paper presents the results of 17 in-depth interviews conducted with Anishinabek (Ojibway and Odawa) living in one First Nations community in northern Ontario, Canada. The findings from the interviews demonstrate that culture is an important component of the link between health and place in everyday life. Incorporating First Nations peoples' perspectives of health and place reveals that the current conceptualizations of health and place within the Geography of Health literature are only partial.

Attitude to Health↗

PubMed2005

Endoscopic transgastric abdominal exploration and organ resection: initial experience in a porcine model.

BACKGROUND & AIMS: The evolution of flexible endoscopes and endoscopic devices has recently enabled per-oral transgastric abdominal exploration in animal models. This study was undertaken to assess the ability to systematically identify abdominopelvic organs and to determine the feasibility of organ resection via the transgastric route. METHODS: Female Yorkshire pigs were used for the study. Under general anesthesia, a gastroscope was used to place a sterile overtube into the esophagus. After antibacterial lavage, the gastric wall was incised, and a sterile dual-channel endoscope was advanced into the peritoneal cavity. Endoscopic abdominal exploration was then methodically performed in 9 animals with oophorectomy and partial hysterectomy in 6 animals. The gastric incision was closed with endoclips. Of the animals that underwent organ resection, 3 were sacrificed immediately after surgery, and the subsequent 3 survived. RESULTS: The peritoneal cavity was accessed uneventfully, and the stomach, liver, small bowel, colon, urinary bladder, uterus, fallopian tubes, and ovaries were able to be evaluated in all cases. The gallbladder could be visualized in only 5 of the 9 animals, and retroperitoneal structures could not be consistently identified. Oophorectomy with partial hysterectomy was performed in 6 animals. The 3 animals in the survival group did well for 24 hours without sequelae. CONCLUSIONS: This study shows the ability of endoscopic transgastric peritoneal exploration to successfully identify most abdominopelvic organs and demonstrates the technical feasibility of transgastric organ resection.

Abdomen↗

PubMedDate not supplied

Molecular Property eXplorer: a novel approach to visualizing SAR using tree-maps and heatmaps.

The tremendous increase in chemical structure and biological activity data brought about through combinatorial chemistry and high-throughput screening technologies has created the need for sophisticated graphical tools for visualizing and exploring structure-activity data. Visualization plays an important role in exploring and understanding relationships within such multidimensional data sets. Many chemoinformatics software applications apply standard clustering techniques to organize structure-activity data, but they differ significantly in their approaches to visualizing clustered data. Molecular Property eXplorer (MPX) is unique in its presentation of clustered data in the form of heatmaps and tree-maps. MPX employs agglomerative hierarchical clustering to organize data on the basis of the similarity between 2D chemical structures or similarity across a predefined profile of biological assay values. Visualization of hierarchical clusters as tree-maps and heatmaps provides simultaneous representation of cluster members along with their associated assay values. Tree-maps convey both the spatial relationship among cluster members and the value of a single property (activity) associated with each member. Heatmaps provide visualization of the cluster members across an activity profile. Unlike a tree-map, however, a heatmap does not convey the spatial relationship between cluster members. MPX seamlessly integrates tree-maps and heatmaps to represent multidimensional structure-activity data in a visually intuitive manner. In addition, MPX provides tools for clustering data on the basis of chemical structure or activity profile, displaying 2D chemical structures, and querying the data based over a specified activity range, or set of chemical structure criteria (e.g., Tanimoto similarity, substructure match, and "R-group" analysis).

Cluster Analysis↗