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At least 217 records · Page 12Linked to original sources

PubMed1999

Laparoscopic exploration of the common bile duct: beyond the learning curve.

BACKGROUND: Bile duct clearance at open cholecystectomy had become normal surgical practice before the introduction of laparoscopic cholecystectomy. However, perceived technical difficulties have deterred many surgeons from treating common bile duct stones at the time of laparoscopic cholecystectomy. This has led to a reliance on preoperative clearance of ducts known to have stones and postoperative clearance of ducts found to have stones at operation or those that subsequently develop complications of retained stones. METHODS: The authors describe a series of 120 consecutive bile duct explorations carried out between April 1991 and February 1997 in a series of 1,237 laparoscopic cholecystectomies. RESULTS: Laparoscopic exploration and clearance of the bile ducts was achieved in 89% of cases in the whole series, and 97% success was attained in the last 60 cases, which also were associated with a decrease in operating time. CONCLUSIONS: We believe that for surgeons familiar with open common bile duct exploration and laparoscopic cholecystectomy, the next logical step is laparoscopic exploration of the common bile duct at the time of cholecystectomy, which is safe and readily mastered.

Chi-Square Distribution↗

PubMed2005

Intentional limited resection for small peripheral lung cancer based on intraoperative pathologic exploration.

OBJECTIVE: The aim of this study was to assess the adequacy of our intentional limited resection for small peripheral lung cancer based on intraoperative pathologic exploration. METHODS: Patients who had stage IA non-small cell lung cancer (NSCLC) with a maximum tumor diameter of 2 cm or less were candidates for limited resection. If bronchioloalveolar carcinoma (BAC) was suspected on computed tomography and intraoperative pathologic exploration revealed the lesion as BAC without foci of active fibroblastic proliferation (Noguchi type A and B), wedge resection was performed. If the tumor was not suspected of being Noguchi type A or B, extended segmentectomy with intraoperative lymph node exploration was performed. RESULTS: Limited resection was performed in 34 patients, wedge resection in 14, and extended segmentectomy in 20. The median follow-up period after wedge resection was 36 months, and all patients are alive with no signs of recurrence. The median follow-up period after extended segmentectomy was 54 months. No local recurrences were found, but distant metastasis was diagnosed in one patient. The 5-year survival rate after extended segmentectomy was 93%. In the same period, lobectomy was performed in 57 patients with stage IA NSCLC with a maximum tumor diameter of 2 cm or less, and the 5-year survival rate was 84%. There were no significant differences in 5-year survival between extended segmentectomy and lobectomy. CONCLUSIONS: Careful selection of patients based on high-resolution computed tomography findings and intraoperative pathologic exploration makes intentional limited resection an acceptable option for the treatment of small peripheral NSCLC.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed1985

Effects of inhibitors of GABA-transaminase on hole-board exploration and on temperature. Relation with effects on quasi-morphine abstinence behaviour induced by sodium dipropylacetate.

Four inhibitors of gamma-aminobutyric acid transaminase (GABA-T) were investigated together with respect to their effects on hole-board exploration and temperature and the relation with effects on quasi-morphine-abstinence behaviour induced by dipropylacetate (DPA) in rats. Amino-oxyacetic acid (AOAA), gamma-acetylenic-GABA (GAG), gamma-vinyl-GABA (GVC) and ethanolamine-O-sulfate (EOS) were found to reduce hole-board exploration especially in the higher doses used, although the time-course of the effect was different for the compounds. For EOS and GVG the decrease in hole-board exploration paralleled a strong hypothermic effect. The compounds AOAA and GAG exerted a less and more transient hypothermic effect. However, the decrease in hole-board exploration did not fall in with this decrease in temperature. AOAA and GAG were found to decrease DPA-induced body shakes and locomotor activity, while GVG and EOS had no effect on body shakes and transient effects but opposite to each other, on locomotor activity. The efficacy of the GABA-T-inhibitors was measured biochemically, and the influence on the activity of glutamate decarboxylase (GAD) was also determined. AOAA and GAG were found to be strong inhibitors of GABA-T whereas the other two compounds were less efficient in the used doses. In addition AOAA and GAG influenced the activity of GAD strongly, while using GVG only a small decrease was found. The results suggest that the anti-quasi-withdrawal, the sedative and the hypothermic effects are not related to each other nor related to an effect on GABA-T. The suppressive effects on quasi-withdrawal body shakes, however, could be related to the inhibition of GAD and a hypothesis involving a compartmentalized action of DPA on GABA-metabolism has been proposed.

4-Aminobutyrate Transaminase↗

PubMed1995

Elevated (+)-maze and hole-board exploration in lurcher mutant mice.

The behavior of lurcher mice, a mutant with degeneration of cerebellar cells, was compared to that of normal mice for three days in two tests of exploration; an elevated (+)-maze and a 4 x 4 hole-board. In the elevated (+)-maze, lurcher mutants visited fewer closed arms than normal mice only on the first test day. Lurcher mutants were slower to emerge from the first closed arm but did not differ from normal mice for entry latencies into the first open arm. The time spent by the mutants in the open arms was higher than that of normal mice, an indication of decreased inhibition to open spaces. In the hole-board, lurcher mutants visited fewer holes than normal mice only on the first day of testing. In proportion to the total number of holes explored, lurcher mutants visited fewer center holes and fewer holes situated next to each other. These results may be due to a lesion-induced tendency to explore a more restricted region of a novel spatial environment and to explore it in a more haphazard fashion.

Animals↗

PubMed1982

Effects of agents which enhance GABA-mediated neurotransmission on licking conflict in rats and exploration in mice.

On the holeboard, exploration (dipping) and locomotion of mice were enhanced by non-sedative doses of anxiolytics; clobazam, diazepam, nitrazepam and flunitrazepam. After chronic dosing the sedative effects of flunitrazepam showed tolerance and the increases in exploration remained while locomotion was less increased. Sodium valproate and to a lesser extent GAG also increased both exploration and locomotion at non-sedative doses. Muscimol, AOAA and urethane increased locomotion at threshold sedative doses with little or no increase in exploration. Baclofen only decreased behaviour. In a drinking test benzodiazepines evoked large increases in punished drinking. After chronic dosing of flunitrazepam there was a greater increase. Sodium valproate evoked a response of similar magnitude to the benzodiazepines whilst GAG evoked a smaller increase. Muscimol did not increase punished drinking. It is suggested that anxiolytic drug actions result from a more selective enhancement of brain GABA transmission.

Animals↗

PubMed1985

Immediate radial nerve palsy complicating fracture of the shaft of the humerus: when is early exploration justified?

A series of 59 patients with immediate complete radial nerve palsy complicating a fracture of the shaft of the humerus was analysed. In 27 patients the radial nerve was explored and the fracture was fixed within 3 weeks of the accident. In 12 other patients exploration was performed after an average of 17 weeks. The remaining 20 patients showed signs of spontaneous recovery within 4 months and were managed conservatively. The mean follow-up time was 3 years. At exploration, laceration, interposition between the fragments or entrapment of the radial nerve in callus was found significantly (P less than 0.01) more often with longitudinal fractures of the distal third (46 per cent) than with transverse fractures of the middle third, in which 85 per cent of the explored cases showed the nerve to be no more than slightly bruised. Useful recovery was seen in 46 patients (78 per cent of the whole series).

Adolescent↗

PubMed1992

Cognitive and noncognitive processes involved in selective object exploration: comparison between young adult and old rats.

The age effects on locomotor activity, object-oriented exploration, habituation, and response to a spatial change were studied in young adult and old rats using an object exploration test. In this test the spatial response was evaluated by the renewal of exploration of a familiar object after its repositioning. The specificity of the spatial response was determined by comparison with control animals not submitted to a spatial change. Male Wistar rats 6 and 24 months old were used. Results showed a significant decrement in locomotor activity, object exploration, and spatial reactivity in old rats. The habituation curve and the reactivity to a new object were preserved. Detail analyses suggest that the spatial deficit of old rats is due to an incapacity to detect the spatial change and not to their poor locomotor or exploratory activity. These results corroborate those obtained in spatial orientation tasks and support the idea that the lack of spatial response observed in old animals is more related to cognitive impairments than to other factors such as sensory, motor, or motivational differences.

Aging↗

PubMed1996

Differential environmental modulations on locomotor activity, exploration and spatial behaviour in young and old rats.

The effects of environmental enrichment on motor activity, exploration and spatial performances were studied in young and old rats. Both young (4 mo old) and old (22 mo old) rats were housed from weaning to testing either in standard or in enriched conditions. All rats were submitted successively to spontaneous alternation test and to object exploration test. Results show that locomotion is decreased by age and enrichment but that the quality of exploration expressed by corrected alternation scores or by the response to spatial change is improved by enrichment sometimes in old, sometimes in young rats. Enrichment tends to accelerate the acquisition of spatial informations in young rats, but it does not succeed to restore the reactivity to spatial change of old rats in the object exploration test. These results, although they do not rule out a persistance of a continued behavioural plasticity during aging, also support the idea that the beneficial effects of environmental stimulations do not succeed to restore high cognitive function, such as the capacity to have a spatial representation, in old animals.

Aging↗

PubMed1977

Effects of parachlorophenylalanine and amphetamine on habituation of exploration.

Parachlorophenylalanine (PCPA, 400 mg/kg) retarded the habituation of exploration in the rat recorded over 3 successive days. A more detailed analysis showed that this was not due to any retention deficit, but was secondary to an impairment of habituation within each session. PCPA also disrupted the response of rats to a change of stimuli. (+)amphetamine (4 mg/kg) prevented exploration in the rat and a 2 mg/kg dose reduced exploration and impaired within-session habituation. (+)amphetamine (1 mg/kg) in mice impaired within-session habituation, without significantly reducing exploration. The nature of the deficits produced by these 2 drugs is discussed.

Animals↗

PubMed1992

From a lunar outpost to Mars: science, policy and the U.S. Space Exploration Initiative.

The U.S. Space Exploration Initiative (SEI) is aimed at the establishment of an outpost for humans on the Moon, followed by the human exploration of Mars. It also encompasses robotic missions to the Moon and Man that will precede and perhaps accompany human presence. Science plays a dual role in SEI. First, many scientific questions must be answered to insure the health and safety of human explorers. Second, scientific investigations will be among the central objectives of human explorers. A substantial body of U.S. policy on SEI has been announced by President Bush. Its implementation is coordinated by the U.S. National Space Council under the Chairmanship of Vice President Quayle. That policy directs the early focus of SEI to be on technology development, including the identification of "high leverage technologies," and the identification of alternative mission architectures. It also envisions international cooperation as an important beneficial aspect of SEI.

Aerospace Medicine↗

PubMed2005

One-gland exploration for mediastinal parathyroid adenomas: cervical and thoracoscopic approaches.

BACKGROUND: In patients with sporadic primary hyperparathyroidism, preoperative localization studies may discover a solitary mediastinal parathyroid adenoma. In this circumstance a 1-gland mediastinal exploration, either cervical or thoracoscopic, may be curative. METHODS: In an 18-month period, 5 of 120 consecutive patients underwent an initial 1-gland mediastinal exploration for a solitary mediastinal parathyroid adenoma and 2 patients had a 1-gland mediastinal exploration for persistent hyperparathyroidism. Clinical presentation, imaging studies, surgical techniques, and outcomes were reviewed. RESULTS: Sestamibi scans showed a mediastinal parathyroid adenoma in all 7 patients. Computed tomography provided anatomic localization of middle mediastinal parathyroid adenomas. A cervical approach was used in 4 patients who had a superior mediastinal parathyroid adenoma. Thoracoscopic excision was performed in 3 patients with a middle mediastinal parathyroid adenoma. No complications occurred. Calcium and parathyroid hormone levels normalized in all patients. CONCLUSIONS: Sporadic primary hyperparathyroidism caused by a solitary mediastinal parathyroid adenoma can be treated successfully with 1-gland mediastinal exploration either by a cervical or a thoracoscopic approach as indicated by localization imaging.

Adenoma↗

PubMed2005

Selective unilateral parathyroid exploration: an effective treatment for primary hyperparathyroidism.

BACKGROUND: Unilateral neck exploration (UNE) is a well-recognized approach in the treatment of primary hyperparathyroidism (PHP). The objective of this study was to review the success of an approach involving UNE guided by preoperative sestamibi (SM) scanning. METHODS: All data were gathered by retrospective chart review. All patients undergoing surgery for the treatment of primary hyperparathyroidism at a tertiary referral center over a 3-year period were included in the study cohort. RESULTS: Fifty-two of 80 patients (65%) had an SM scan consistent with a solitary adenoma and were eligible for a UNE, with 57.5% (46/80) undergoing a UNE. Seventy-seven of 80 (96.3%) patients were normocalcemic after initial neck exploration. UNE was curative in 50 of 52 (96.2%) UNE eligible patients and required less operative time than bilateral neck exploration (mean, 60 versus 87 minutes). CONCLUSION: Selective unilateral neck exploration, guided by preoperative SM scanning, is an effective surgical approach for the management of primary hyperparathyroidism.

Adenoma↗

PubMed2004

The balance between approach and avoidance behaviors in a novel object exploration paradigm in mice.

Approach and avoidance are critical components of novelty seeking, which plays an important role in susceptibility to drug abuse and aspects of cognition. This experiment was designed to examine whether brief periods of handling or prior exposure to a novel environment affect various measures of novel object exploration in mice. Forty male C57BL/6J mice were handled by the experimenter or received minimal exposure to human contact. In addition to manipulating the degree of familiarity with the experimenter (handling), we also manipulated the degree of familiarity with the object. All mice were tested over a 3-day period. On day 1, all mice were tested in the open field for 60 min. On day 2, there were two, 30-min sessions. In the first 30-min session, there was no object present. In the second 30-min session, half of the mice were exposed to a novel object. On day 3, all mice were placed in the open field for 30 min followed by a 30-min period in which the object was placed in the center of the open field. Handled mice showed a trend toward more object exploration on day 2 compared to non-handled mice. Mice with prior exposure to the novel object showed more object exploration compared to object-naïve mice on day 3. These results are consistent with the hypothesis that a certain degree of familiarity with the object or with the experimenter decreases avoidance and increases exploration of novel stimuli. In combination, these results show that the approach and avoidance dimensions of novelty seeking can be manipulated experimentally and may be used in subsequent studies to examine the effects of drugs of abuse.

Animals↗

PubMed2004

Medial prefrontal cortex is involved in spatial temporal order memory but not spatial recognition memory in tests relying on spontaneous exploration in rats.

The present study describes two novel tasks relying on spontaneous patterns of exploration in a radial-arm maze that can be used to assess spatial recognition memory and spatial temporal order memory (i.e. memory for the order in which places have been visited) in the rat. In the recognition memory task, rats were permitted to freely explore two arms in the maze on a first trial and one 'familiar' arm and one novelly located arm on a second trial 105 min later. In the temporal order memory task, rats were permitted to explore two arms in the maze on a first trial, two novel arms on a second trial 60 min later, and one 'older familiar' arm and one 'more recent familiar' arm on a third trial 45 min later. Using these tasks, we found that rats direct greater exploration at a novel than a familiar arm location, thus showing long-term spatial recognition memory, and at an older familiar arm than a more recent familiar arm, thus showing long-term spatial temporal order memory. Lidocaine inactivation of the mPFC prior to the final trial in each task disrupted performance on the temporal order but not the recognition memory task, thereby demonstrating a role for the mPFC in the retrieval and/or use of temporal order information but not in spatial memory per se. These findings highlight the specific involvement of the rat mPFC in temporal order memory and have important implications for a broader understanding of mPFC function.

Analysis of Variance↗

PubMed2006

Quantification of three-dimensional exploration in the cylinder test by the common marmoset (Callithrix jacchus).

The increasing trend in use of marmoset monkeys in behavioral studies has necessitated a greater understanding of their natural behavior, especially within confined spatial environments. One way to approach this issue is to examine locomotor and exploratory strategies using the cylinder test, as done recently for the rat by Gharbawie et al. [Gharbawie OA, Whishaw PA, Whishaw IQ. The topography of three-dimensional exploration: a new quantification of vertical and horizontal exploration, postural support, and exploratory bouts in the cylinder test. Behav Brain Res 2004;151:125-35]. We have used this paradigm in conjunction with Eshkol-Wachmann movement analysis in marmoset monkeys. We provide evidence that marmosets display systematic changes in both horizontal and vertical progressions during exploration. Quantitative analysis and comparison with the extant data in rats showed both similarities and differences. For example, both species display horizontal and vertical scanning movements, although the variability is considerably greater for the marmoset. The horizontal progressions consist of head scans, turning, and stepping. The amplitude of these progressions oscillates and decreases with trial duration. Vertical progressions, which consist of rears, head scans, and descent, also strongly oscillate but with constant mean amplitude during a trial. The difference between the two species is most evident in locomotor behavior. Rats use their forepaws primarily for postural support and follow forequarter movements while body weight shifts are generated by the hind limbs. Marmosets, however, can hold a vertical position without hand support and display more complex movement characteristics during exploration. The data from this study should be of use in designing experiments in which marmosets are engaged in free-roaming behavior within a confined space.

Animals↗

PubMed2006

Temporal stability of novelty exploration in mice exposed to different open field tests.

We investigated behavioural activity and temporal distribution (patterning) of mouse exploration in different open field (OF) arenas. Mice of 129S1 (S1) strain were subjected in parallel to three different OF arenas (Experiment 1), two different OF arenas in two trials (Experiment 2) or two trials of the same OF test (Experiment 3). Overall, mice demonstrated a high degree of similarity in the temporal profile of novelty-induced horizontal and vertical exploration (regardless of the size, colour and shape of the OF), which remained stable in subsequent OF exposures. In Experiments 4 and 5, we tested F1 hybrid mice (BALB/c-S1; NMRI-S1), and Vitamin D receptor knockout mice (generated on S1 genetic background), again showing strikingly similar temporal patterns of their OF exploration, despite marked behavioural strain differences in anxiety and activity. These results suggest that mice are characterised by stability of temporal organization of their exploration in different OF novelty situations.

Animals↗

PubMed2005

Influence of explorer tip diameter in identifying restoration margin discrepancies.

OBJECTIVES: Evaluations of the marginal adaptation of restorations in clinical trials rely on subjective assessments by evaluators. The purpose of the present study was to assess the use of dental explorers with different tip diameters to detect simulated marginal discrepancies. METHODS: Using three devices simulating vertical steps, horizontal gaps, and the combination of vertical and horizontal discrepancies and explorers with five different tip diameters, 10 experienced dental faculty members were asked to identify discrepancies at the boundary between Alfa (replacement unnecessarily) and Bravo (replacement questionable) ratings, according to modified United States Public Health Service criteria. RESULTS: A significant correlation was found between the tip diameters of the explorers and the Alfa/Bravo boundaries for the horizontal gaps, but not for the vertical steps. CONCLUSION: It was concluded that the tip diameter of dental explorers had no significant effect on the detection of vertical steps, but had a significant effect on the detection of horizontal gaps. The diagnosis of restoration marginal discrepancies and the rating of marginal adaptation in clinical trials may subsequently be found to be best achieved using techniques other than the probing of restoration margins.

Dental Instruments↗

PubMed2004

Unilateral neck exploration for primary hyperparathyroidism.

Focused unilateral cervical exploration is a controversial alternative to conventional bilateral neck exploration for primary hyperparathyroidism (HPT) due to solitary adenoma. Development of preoperative localization techniques, notably isotope scintigraphy and small-part, real-time ultrasonography, has increased preoperative parathyroid tumor identification. Critics of scan directed unilateral neck exploration argue it may overlook enlarged parathyroid glands on the unexplored side, increasing the incidence of persistent and recurrent hypercalcemia. Our experience of this operation and prolonged follow-up of patients, however, confirm that it does not increase risk of persistent or recurrent HPT if a strict selection protocol is observed. This ensures the confident further development of minimally invasive surgical procedures for HPT based on the principle of a focused exploration following preoperative localization of the parathyroid adenoma.

Adenoma↗