SEARCH · PubMed Health

Results for “Exploration”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources

PubMed2006

A visual-haptic Necker cube reveals temporal constraints on intersensory merging during perceptual exploration.

When viewing a three-dimensional Necker cube with one eye, participants can experience illusory reversals even while they feel the cube with their hands. This surprising property of the visual-haptic Necker cube affords a unique opportunity to investigate temporal constraints on interactions between vision and touch during extended observation of a three-dimensional object. Our observers reported reversals while they viewed the cube and, at the same time, they either held it with two-finger grips, felt it with while their hands remained stationary, or actively explored it by moving one hand. Consistent with a multisensory approach to three-dimensional form perception, touch had a clear effect on both the number and the duration of illusory percepts. Additionally, when observers alternated between stationary and moving periods during exploration, transitions from stationary to moving-hand haptics played a crucial role in inhibiting illusory reversals. A temporal analysis of the probability of first reversals occurring after different types of motor transition revealed a "vetoing window" initiating approximately 2s after the transition and lasting at least another 1-2s. Implications for multisensory processes during exploration are discussed.

Form Perception↗

PubMed2005

Exploration and risk assessment in female wild house mice (Mus musculus musculus) and two laboratory strains.

In an evolutionary prospective, it is possible that female mice have a differential perception of novel events than male mice and use a different behavioural strategy for risk assessment. However, female mice are less studied than male mice in behavioural tests of emotional reactivity. The aim of the present study was to investigate how wild-derived female house mice differ from domesticated female mice in their risk assessment strategy. A total of 46 adult female mice, 14 BALB/c, 16 C57BL/6 and 14 Wild mice were tested in the Concentric Square Field (CSF), Open Field (OF) and Elevated Plus Maze (EPM) at three consecutive days. Parameters from all three tests were categorized according to their relevance to activity, exploration, approach-avoidance and use of open areas-shelter. Principal Component Analysis (PCA-SIMCA) of the animals' behaviour in the CSF arena was performed both for females alone and in comparison with earlier findings in male mice under the same test conditions. The results clearly show that female wild mice had a higher avoidance of open areas than the laboratory strains. There was also a trend indicating differences in exploration and approach-avoidance between female Wild and the laboratory strains. The multivariate test, CSF, was able to detect differences between Wild and laboratory strains in three (exploration, approach-avoidance, open-shelter) of the four functional categories measured. Wild female mice also had a higher frequency of rearing and grooming and a lower duration in the corridors in the CSF. Clear strain differences were found between BALB and C57BL in all tests where BALB generally had higher risk assessment and lower risk taking than C57BL. No general sex differences were found, however the sex differences were greater in Wild mice compared to the laboratory strains.

Analysis of Variance↗

PubMed2005

A prospective evaluation of laparoscopic exploration with intraoperative ultrasound as a technique for localizing sporadic insulinomas.

BACKGROUND: Preoperative imaging studies localize insulinomas in less than 50% of patients. Arteriography with calcium stimulation and venous sampling (ASVS) regionalizes greater than 90% of insulinomas but requires specialized expertise and an invasive procedure. This prospective study evaluated laparoscopic exploration with IOUS compared with the other localization procedures in patients with a sporadic insulinoma. METHODS: Between March 2001 and October 2004, 14 patients (7 women and 7 men; mean age, 53) with an insulinoma were enrolled in an IRB-approved protocol. Computed tomography, magnetic resonance imaging, ultrasound scan, and arteriography with calcium stimulation and venous sampling were performed preoperatively. A surgeon, blinded to the results of the localizing studies, performed a laparoscopic exploration with intraoperative ultrasound (IOUS). At the completion of the exploration, the success of laparoscopy for localization was scored, and the tumor was resected. RESULTS: Twelve of 14 tumors were localized successfully before laparoscopy (noninvasive, 7 of 14; invasive, 11 of 14). Laparoscopic IOUS localized successfully 12 of 14 tumors. All lesions were resected, and all patients were cured (median follow-up, 36 months). CONCLUSION: Laparoscopic IOUS identified 86% of tumors. The authors consider laparoscopic IOUS to be equivalent to ASVS in localizing insulinomas. Further study is therefore warranted to determine the role of laparoscopy with IOUS in the localization and treatment algorithm for patients with sporadic insulinoma.

Adult↗

PubMed2005

Exploring the microbial biodegradation and biotransformation gene pool.

Similar to the New World explorers of the 16th and 17th century, microbiologists today find themselves at the edge of unknown territory. It is estimated that only 0.1-1% of microorganisms can be cultivated using current techniques; the vastness of microbial lifestyles remains to be explored. Because the microbial metagenome is the largest reservoir of genes that determine enzymatic reactions, new techniques are being developed to identify the genes that underlie many valuable chemical biotransformations carried out by microbes, particularly in pathways for biodegradation of recalcitrant and xenobiotic molecules. Our knowledge of catabolic routes built on research during the past 40 years is a solid basis from which to venture on to the little-explored pathways that might exist in nature. However, it is clear that the vastness of information to be obtained requires astute experimental strategies for finding novel reactions.

Bacteria↗

PubMed2003

Is contralateral exploration necessary in girls with unilateral inguinal hernia?

BACKGROUND/PURPOSE: Routine contralateral groin exploration in girls with unilateral inguinal hernia (UIH) continues to be controversial. The aim of this study was to determine the incidence of contralateral hernia development in girls after UIH repair. METHODS: Between 1972 and 2000, 391 girls underwent repair of UIH. Ninety-one (23%) of the 391 girls underwent routine contralateral exploration during UIH repair and were excluded from the study. The median age at operation in the remaining 300 girls was 3.3 years (range, 1 month to 14 years). Two hundred ten (70%) girls had right-sided and 90 (30%) had left-sided UIH. Familial history of hernia was identified in 8 (3%) patients. The follow-up ranged from 1.5 to 14 years. Mann-Whitney U test was used for intergroup comparison. RESULTS: A contralateral hernia developed in 24 (8%) of the 300 patients who had unilateral repair of inguinal hernia. Median time from operation to occurrence of the contralateral hernia was 3 years (range, 1 to 4 years). Age at operation, side of hernia, and familial history did not influence the development of contralateral hernia. CONCLUSIONS: These data suggest that the low incidence of contralateral hernia development in girls undergoing UIH repair does not justify routine contralateral groin exploration.

Adolescent↗

PubMed1992

Further evidence against the routine use of parathyroid ultrasonography prior to initial neck exploration for hyperparathyroidism.

The role of preoperative localization tests in patients undergoing initial neck exploration for hyperparathyroidism (HPT) is controversial. The use of parathyroid ultrasonography (US) in 46 patients (7 men, 39 women; mean age: 60 years) who underwent initial neck exploration for hypercalcemia and who had the diagnosis of HPT confirmed at surgery is reported. At surgery, a single adenoma was found in 40 patients and multiple hyperplastic glands in 6 patients. Of the 40 adenomas, only 22 (58%) were localized to the correct side by the preoperative US, and only 5 of 18 hyperplastic glands (28%) were correctly localized. The rates of false-positive and false-negative results were 10% and 46%, respectively. The sensitivity of parathyroid US was 54%, the specificity 90%, and the accuracy 70%. The low sensitivity and accuracy and the high rate of false-negative test results that were observed suggest that there is no role for the routine use of parathyroid US in patients undergoing initial neck exploration for HPT.

Adenoma↗

PubMed1993

Parathyroid localization prior to primary exploration.

The success of parathyroid surgery is based on accurate localization of normal and abnormal parathyroid glands, knowledge of the pathologic conditions, and meticulous dissection during removal of the abnormal glands. Although parathyroid localization is essential in cases requiring re-exploration, there is considerable controversy regarding the indications for localization studies prior to primary exploration, since the success rate for surgery exceeds 90% to 95%. However, in specific circumstances, including diagnostic problems, technical considerations, and high-risk patient factors, preoperative parathyroid localization assists the operating surgeon even during the primary cervical exploration. The purpose of this paper is to define these specific circumstances and discuss the appropriate studies.

Adolescent↗

PubMed1999

Success of cervical exploration for patients with asymptomatic primary hyperparathyroidism.

BACKGROUND: This study examined the success and safety of cervical exploration in patients with asymptomatic primary hyperparathyroidism compared with those with symptomatic disease. METHODS: Records of patients undergoing cervical exploration for primary hyperparathyroidism from June 1990 to October 1996 were reviewed. Patients were divided into three groups: (1) asymptomatic, (2) symptomatic, and (3) afflicted (those with associated complications). Information collected consisted of preoperative and postoperative symptoms, serum calcium and parathyroid hormone levels (PTH), and descriptions of pathologic and operative findings. RESULTS: Sixty-one patients were identified. Nineteen (31%) had no symptoms, 21 (34%) had subjective symptoms, and 21 had associated conditions, as described. Average preoperative and postoperative calcium levels were 11.5 mg% and 8.5 mg%, respectively. Average PTH levels also fell from 142 pg/mL to 49 pg/mL after surgery. Preoperative and postoperative calcium and PTH levels for the three groups showed no significant differences. The success of surgery in identifying pathology ranged from 90.5% to 95%, and again showed no difference among the three groups. Long-term morbidity (>6 months) in all groups was 0%. CONCLUSIONS: Cervical exploration and parathyroidectomy for asymptomatic primary hyperparathryoidism is safe and has similar success rates in identifying pathology and correcting biochemical abnormalities compared with patients with symptomatic disease.

Adenoma↗

PubMed1998

Role of the cerebellum in exploration behavior.

Compared to +/+ mice, Lurcher (+/Lc) mutant mice whose cerebellar cortex is lacking almost all Purkinje cells and granule cells, exhibit a low level of exploration; this deficit is not due to a low level of activity but to both a decreased motivation to explore a novel environment and to spatial deficits. The characteristics of exploration in cerebellectomized +/+ and +/Lc mice suggest that the cerebellum is involved not only in cognitive but also in motivational processes.

Animals↗

PubMed1983

Use of fiberoptic choledochoscope in common bile duct and intrahepatic duct exploration.

This report summarizes our experience with 339 consecutive flexible fiberoptic choledochoscopic examinations performed in the course of 598 common bile duct explorations for biliary tract stones. Routine choledochoscopy added 5 to 10 minutes to the operation and caused no complications. In 81 of the patients, additional stones were discovered with choledochofiberscopy after completion of routine bile duct exploration. Postoperative cholangiography demonstrated a retained stone in 57 patients (two in the common bile duct and 55 in the intrahepatic ducts). Forty-two patients with stones retained in the intrahepatic ducts were diagnosed during operation with the fiberoptic choledochoscope, but those stones were very difficult for us to remove. The accuracy of postexploratory choledochoscopy in diagnosis of stones in the common bile duct and intrahepatic ducts was 99.0% and 90.5%, respectively. Choledochofiberscopy is useful in exploration of the common bile duct and a safe procedure in the diagnosis of biliary tract stones during operation.

Bile Ducts, Intrahepatic↗

PubMed1994

The panopticon re-visited?: an exploration of the social and political dimensions of contemporary health care and nursing practice.

Insights from critical and postmodern perspectives are used to explore some of the aspects of contemporary nursing practice and health care which are taken for granted. Such an exploration begins to deconstruct the power relations implicit within the socio-political context of the health care arena in which nursing operates. In particular, the work of the French philosopher Michel Foucault is used to explore the discourses of the various health care "experts". Aspects of women's health and nursing practice are used as exemplars of the limiting effects of such discourses.

Delivery of Health Care↗

PubMed1993

Do all children with an acute scrotum require exploration?

A total of 77 consecutive children ranging in age from 1 day to 17 years was evaluated for an acute scrotum by a single examiner (E. J. K.). In 10 children a definite diagnosis of acute spermatic cord torsion was made based upon the history and physical examination. No imaging studies were performed and torsion was confirmed at surgery in 9 children. The diagnosis of testis torsion was not as clear-cut in the remaining 67 children and, therefore, a color Doppler ultrasound was performed before any surgical intervention. The study demonstrated normal or increased blood flow in 55 of these children and none proved to have testicular torsion, although other scrotal pathology requiring surgery was noted in 5 children. Twelve children did not demonstrate evidence of testicular blood flow on the color Doppler ultrasound and all had surgical confirmation of testis torsion. We conclude that in our experience the majority (71%) of children with an acute scrotum did not require immediate surgical exploration. Color Doppler ultrasound can reliably identify those children with an acute scrotum who require exploration and spare the majority needless surgery. Routine scrotal exploration is no longer necessary for all children with an acute scrotum.

Acute Disease↗

PubMed1992

Laparoscopy for nonpalpable testes in childhood: is inguinal exploration also necessary when vas and vessels exit the inguinal ring?

Laparoscopy has proved to be a safe method for determining the status for nonpalpable testes. In a combined series 52 boys with 57 nonpalpable testes were evaluated laparoscopically. Of the 57 nonpalpable testes 26 were located above the internal inguinal ring (abdominal), 4 were found more distally, and blind-ending vas and vessels terminated in the abdomen in 3, and beyond the internal ring (vanished testes) in 24. Of 29 abdominal testes primary orchiopexy was performed in 15, 4 were removed, the vessels were transected (Fowler-Stephens) in 5, stage 1 of staged repairs was done in 2, distinct laparoscopic evidence of blind-ending vessels and vas obviated further surgery in 2, and testis was not identified either laparoscopically or by abdominal exploration. Finally, inguinal exploration in 28 children in whom vas and vessels were found to exit the internal ring resulted in localization of 4 testes that were brought into the scrotum. Removal of 23 testicular nubbins and their evaluation histologically resulted in identification of viable tubular structures in 3. We recommend inguinal exploration in all children who on laparoscopy are found to have vas and vessels exit the internal ring, and removal of testicular nubbins.

Blood Vessels↗

PubMed1983

When to use the Chevassu maneuver during exploration of intrascrotal masses.

As many as 50 per cent of explorations for intrascrotal masses result in orchiectomy for benign disease. The most common diagnoses are hydrocele, epididymitis and benign testicular tumors. Many of these diagnoses could be made before orchiectomy if the tunica vaginalis and, occasionally, the tunica albuginea were opened, and the lesion biopsied. However, violation of the testicular tunics traditionally has been considered taboo because of the dangers of tumor seeding. In 1906 Chevassu suggested inguinal exploration and occlusion of the testicular vessels before biopsy of suspicious lesions. We have added scrotal hypothermia, double ligation of the gubernaculum before its division and irrigation with distilled water to provide a procedure that adheres to the principles of good cancer surgery. Its use during inguinal explorations for suspicious intrascrotal masses in 5 patients led to a benign diagnosis and preservation of the testis in 3 instances without subsequent testicular atrophy. Its judicious use can decrease the incidence of orchiectomy for benign disease.

Adolescent↗

PubMed1997

Using models to explore whole-body metabolism and accessing models through a model library.

A model is a mathematical representation of a system that can be used to explore the system in a number of ways: to determine the system's internal connections, to calculate properties of the system such as flow rates and pool sizes, and to make predictions about the system's behavior under different conditions. The use of modeling to explore whole-body metabolism is demonstrated using a compartmental model of zinc kinetics as an example. Because models are useful tools for exploring systems, a facility called a "model library" is being established on the Internet to provide access to working versions of published models.

Animals↗

PubMed2005

[Postoperative results after arthroscopic treatment of rotator cuff calcifying tendonitis, with or without associated glenohumeral exploration].

PURPOSE OF THE STUDY: Arthroscopic treatment of calcifying tendonitis usually includes a glenohumeral exploration first, followed by deposit removal via a bursal approach. The aim of this study was to analyze the relevance of a systematic glenohumeral exploration during arthroscopic treatment of calcified tendonitis of the rotator cuff. MATERIAL AND METHODS: Sixty-four consecutive patients treated by arthroscopic removal of calcific deposits in the rotator cuff were studied retrospectively. All patients had had at least six months of medical treatment. The treatment involved a glenohumeral approach in 32 patients (group GH) and an isolated bursal approach in 32 (group B). Both groups were similar with regard to epidemiological data and deposit aspect. In all cases, the deposit was removed from the bursal side and the cuff was not sutured. Assessment included duration of pain after surgery, Constant score, and x-ray aspect at six months follow-up and the delay for return to work. RESULTS: In the GH group, degenerative changes were noted on the labrum in three cases and a partial tear of the supraspinatus in two. No lesions noted in the glenohumeral joint required specific treatment. Postoperatively, the average duration of pain was significantly higher in group GH than in group B (11 weeks versus 6 weeks, p < 0.05) with a significant latency in return-to-work (12 weeks versus 5 weeks, p < 0.05). At six months follow-up, there was no difference between the groups for Constant score and deposit disappearance. DISCUSSION: Systematic exploration of the glenohumeral joint is not relevant in the arthroscopic treatment of calcified tendonitis and has a negative effect. Considering these results and those previously published in the literature, we recommend using an isolated bursal approach for arthroscopic calcifying tendonitis removal.

Adult↗

PubMed2005

[A new method of visual exploration analysis].

The term visual field corresponds to the angular field of view that is seen by the eyes when they are fixed on a point straight-ahead. In neurological patients--e.g. stroke, trauma, or tumour patients--visual field function can be restricted, depending on lesion site and size. In contrast, the term "functional visual field" describes the area of visual field responsiveness under more ordinary viewing conditions. The visual exploration, i.e. the capacity to explore and analyze our visual world, is dependent on the integrity of the visual system and the oculomotor system which has to move the fovea from one object of interest to the next. In this paper, we present a new method to assess the functional visual field, conceptualized as the area that a patient actively scans with eye movements to detect predefined targets placed on everyday scenes. This method allows us to compare three levels of visual field function: (a) the spatial distribution of successful search (hits, i.e. which targets did the patient find?), (b) the spatial distribution of fixations (i.e. where did the patient preferentially search for targets?), and (c) the retinotopic level (i.e. the visual field assessed by perimetry). By integrating these three levels, one can evaluate functional outcomes of visual field disorders. Of particular importance is the question of how a patient compensates for a visual field loss with appropriate eye movements. A further clinical application of this method is the comparison of pre- with post-treatment data. Patients with visual field disorders usually undergo specific exploration trainings, aimed at enhancing the number and amplitude of saccades towards the region of the visual field deficit. The first experiences and clinical application with this method are presented here.

Eye Movements↗

PubMed1997

Experimental development of an endoscopic approach to neck exploration and parathyroidectomy.

BACKGROUND: Recent advances in minimally invasive surgical technology have the potential to lead to new applications outside body cavities. The purpose of the present study was to develop techniques for obtaining endoscopic exposure and access to the pretracheal space in the neck with the goal of performing neck exploration and parathyroidectomy and to evaluate the safety and efficacy of such an approach experimentally. METHODS: The technique for endoscopic neck exploration was developed in eight adult mongrel dogs and was further evaluated in a survival dog model and in human cadavers. The pretracheal space was accessed by a 2.5 cm midline incision in the lower neck. This space was expanded with a balloon dissector, and exposure was maintained with an external lift device. A 5 or 10/12 mm midline port and two to four lateral 5 mm cervical ports were placed, and dissection was carried out with pediatric endoscopic instruments and an ultrasonic coagulator. Excised parathyroid tissue was verified histologically. RESULTS: Two-gland parathyroidectomy was successfully completed in five of six dogs; inadequate exposure led to a failed procedure in one animal. Mean operative time was 130 +/- 6 minutes, and there were no operative complications. Serum calcium levels did not change significantly after operation (p = not significant). At autopsy, approximately 20 ml of clear sterile fluid was present in the pretracheal space of every dog. In five human cadavers mean dissection time for attempted four-gland parathyroidectomy was 69 +/- 38 minutes (range, 45 to 135 minutes). Four of four parathyroids were identified and removed in two patients, three of three parathyroids in one patient, three of four parathyroids in one patient, and two of four parathyroids in one patient. CONCLUSIONS: Parathyroidectomy may be performed safely and reliably in an animal model with minimally invasive techniques that can be applied to parathyroid dissection in human cadavers. These results suggest that an endoscopic approach to neck exploration and parathyroidectomy is potentially feasible and may warrant further study in clinical trials.

Animals↗