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At least 253 records · Page 14Linked to original sources

3D-visualization improves the dry-lab coronary anastomoses using the Zeus robotic system.

BACKGROUND: Robotic surgical instruments enable quick and precise movements and may allow complete endoscopic coronary artery bypass grafting. However, cardiac surgeons will have to become familiar with this technology and endoscopic viewing. We present our training program with special focus on 2D- and 3D-visualization. METHODS: A thoracic skeleton, covered with a neoprene suit, served as model for the chest wall. Either a glove, fixed on a metal plate, or a pig heart were placed inside for training. On the glove, a suture line consisting of two lines of 16 points each, with a distance of 2 mm between each point, was stamped. On the pig heart, the LAD was prepared and incised; subsequently an anastomosis was done using the dissected right coronary artery as a graft. The time required was measured for both models. For suturing, the Zeus System (Computer Motion, Goleta, CA) was used and the third robotic arm positioned the endoscopic camera. The scopes were connected to a 3D-camera and the picture was displayed on a headset with two integrated monitors. Visualization was set to either 2D or 3D. Three surgeons were involved in the study. Each one did at least 12 anastomoses on 2D and 3D. RESULTS: The three surgeons involved showed a clear and rapid learning curve. The times required for the suture line decreased from 12.5 +/- 1.6 to 8.5 +/- 0.5 minutes with 2D and from 11.9 +/- 5.4 to 7.8 +/- 0.5 minutes for 3D respectively. This decrease did reach statistical significance (p = 0.03). In the pig heart model, the anastomosis times decreased from 33.2 +/- 8.4 to 15.7 +/- 0.3 minutes with 3D-visualization, and from 36.2 +/- 2.2 to 29.5 +/- 3.3 minutes with 2D. The decrease in anastomosis time did again reach significance (p = 0.025). At the end of the study, the times achieved with 2D-visualization were significantly longer than those with 3D (p = 0.01). CONCLUSIONS: A surgical training program is mandatory to become familiar with these new technologies. Both models showed learning curves over an acceptable time course. 3D-visualization facilitated quick and precise movements, thus resulting in shorter anastomosis times.

Anastomosis, Surgical↗

Influence of maternal dietary fat upon rat pups.

Mother rats were fed purified rations containing different fats during gestation and lactation and at 1 day after parturition. Litter sizes were reduced to 2 male and 2 female pups. The behavior and the brain chemical composition of these selected pups were compared with similarly selected pups from dams fed a commercial ration. All offspring were fed a commercial ration after weaning. Pups from dams fed 20% safflower oil were similar to controls. Feeding 20% cocoa butter to dams resulted in pups with reduced exploratory activity and with a rapid learning performance in a T-maze, employing the aversive stimulation of an electrical shock. Feeding dams a fat-free ration produced pups which had reduced rates of growth, small brains at 2 months of age, and low brain concentrations of cholesterol, DNA, and RNA.

Animals↗

Ultrasonography performed by primary care residents for abdominal aortic aneurysm screening.

A prospective pilot study was undertaken to assess a protocol to educate primary care residents in how to personally perform ultrasonography for abdominal aortic aneurysm screening. Resident exams were proctored by a primary care physician trained in ultrasonography and were scored on the level of competence in doing the examination. Patients had ultrasound performed by a resident, followed by repeat examination by the vascular lab. Primary care resident abdominal aortic imaging was achieved in 79 of 80 attempts. Four abdominal aortic aneurysms were identified. There were 75 normal examinations; resident ultrasonography results were consistent with the results of the vascular lab. Ten residents achieved an abdominal aortic ultrasound-independent competence level after an average of 3.4 proctored exams. The main outcome of this study is that a primary care resident, with minimal training in ultrasonography imaging, is able to rapidly learn the technique of ultrasonography imaging of the abdominal aorta.

Aortic Aneurysm, Abdominal↗

The monkey's prefrontal cortex functions in motor programming.

A new experimental approach is presented which resulted in clarification of the specific functions of the monkey’s prefrontal cortex. Monkeys with chronically implanted transcortical nonpolarizable electrodes were trained on delayed response (DR) and visual delayed matching-to-sample (DMS) tasks. The onset of the trial for each group depended upon on-line computer detection of one of the specified events: FN – surface-negative steady potential shifts (SPS) from principalis cortex; MN – a similar SPS from precentral cortex; FB – near baseline SP from principalis cortex; LEM – rightward eye deviations; and YC – controls, with intertrial intervals yoked to those of other monkeys. Monkeys were trained with 1-s cue presentations. on successive delays of 2 to 12 s. The DR acquisition rate by the FN group was substantially faster than that of any other group, as indicated by its mean error that was only 17.24 percent the YC group’s error. The MN and LEM monkeys acquired the task at the same rates as the YCs, while the FB monkeys were the slowest learners. The correct DR performance transferred to testing with constant intertrial intervals (without preconditions). Subsequent on-line tests with brief (0.1 s) cue duration showed high DR performance by the FN, but not by other groups. No similar rapid learning was found with the DMS task. The findings from this, and other experiments, suggest that the major function of principalis cortex is the selection, or programming of delayed spatial choice responses. The view seems consonant with interpretations for the role of the human prefrontal cortex.

Animals↗

Interacting Cache memories: evidence for flexible memory use by Western Scrub-Jays (Aphelocoma californica).

When Western Scrub-Jays (Aphelocoma californica) cached and recovered perishable crickets, N. S. Clayton, K. S. Yu, and A. Dickinson (2001) reported that the jays rapidly learned to search for fresh crickets after a 1-day retention interval (RI) between caching and recovery but to avoid searching for perished crickets after a 4-day RI. In the present experiments, the jays generalized their search preference for crickets to intermediate RIs and used novel information about the rate of decay of crickets presented during the RI to reverse these search preferences at recovery. The authors interpret this reversal as evidence that the birds can integrate information about the caching episode with new information presented during the RI.

Animals↗

[Flexible ureteroscopy and holmium-Yag laser: material and technique].

Flexible ureteroscopy combined with Holmium-YAG laser is an effective, reproducible and minimally traumatic diagnostic and therapeutic technique perfectly adapted to diseases of the upper urinary tract. This technology must be part of the therapeutic armamentarium of any centre involved in the management of urinary stones. The technical facilities must be complete and adapted. Flexible ureteroscopy is a technique with a rapid learning curve once the operator is familiar with all of the equipment. This article describes the material and technique of flexible ureteroscopy combined with Holmium-YAG laser.

Equipment Design↗

[The reorganization of bimanual movements during formation of a lateralized motor food skill in rats].

After 48 h food deprivation adult Wistar rats were trained to obtain food from a narrow tube feeder using the forepaw under conditions of free choice of limb. At the initial stage of training animals use both paws: the grasping and extraction with one paw can be alternated with food grasping and extraction with another paw, and both paws can be alternately involved in movements preceding this grasping. Character of reorganization of bimanual movements was analyzed during training rats with different motor preference (right-handed and left-handed animals). It was shown that in the process of acquisition of both right- and left-hand skills, bimanual reactions in the anticipating attempts disappeared later than in the final successful movements. The disappearance of bimanual movements in the anticipating attempts is considered as an index of the maximum skill lateralization and acquisition of a novel lateralized movement coordination. The results suggest that left-handed rats more rapidly learn a novel movement coordination than right-handed animals.

Animals↗

Bilateral congenital choanal atresia at age 16: an interesting case.

A bilateral congenital posterior choanal atresia case diagnosed at the age of 16 is presented. Although bilateral congenital choanal atresia causes acute life-threatening respiratory obstruction in newborns, this case was able to compensate by rapidly learning mouth breathing and the diagnosis did escape detection for years. The patient was treated successfully via transpalatal approach.

Adolescent↗

Temporal specificity of fear conditioning: effects of different conditioned stimulus-unconditioned stimulus intervals on the fear-potentiated startle effect.

Separate groups of rats were given 30 pairings of a light (conditioned stimulus, CS) and 500-ms shock (unconditioned stimulus, US) at CS-US intervals of 0, 25, 50, 100, 200, 800, 3,200, 12,800, or 51,200 ms. Other groups had lights and shocks inconsistently paired. The startle reflex was elicited 2-4 days later with a noise burst alone or 25-51,200 ms after light onset. After CS-US pairings over a wide range of intervals (25-51,200 ms), startle was potentiated in testing, sometimes as rapidly as 50 ms after light onset. Magnitude of potentiation and resistance to extinction were generally greater with longer CS-US intervals. In several groups, potentiation was maximal at a test interval that matched the CS-US interval used in training. This temporal specificity sharpened with increasing numbers of training trials but even occurred with a single training trial in which a 51,200-ms CS-US interval was used. The data indicate that even during simple fear conditioning, animals rapidly learn a temporal CS-US relationship. This has important implications for understanding the neural mechanisms of fear conditioning.

Animals↗

Computer corner #18. A computer program suitable for routine hip replacement follow up and clinical research.

A computer program was developed to facilitate routine follow up examination of patients with total hip replacements and to allow detailed analysis of the collected data for clinical research purposes. Information on more than 800 low friction arthroplasties has now been entered into the computer program. The system is versatile and can be modified to suit particular needs. The method of entering and recalling data can be learned rapidly by those unfamiliar with computers, however, analysis of the data requires advanced computer expertise. Hardware and software requirements for the program are listed at the end of this article.

Follow-Up Studies↗

Functional significance of different amygdalar areas in performance of instrumental conditioned alimentary reflexes in rats.

Bilateral lesions of the basolateral amygdala caused facilitation of instrumental alimentary conditioned reflexes while bilateral cortico-medial amygdala damage produced inhibition of conditioned responses. The most rapid learning was in rats after basolateral lesions whereas the cortico-medial rats required more trials to criterion than controls. In basolateral rats the largest number of intertrial responses were found, while cortico-medial rats had a small number of ITR in criterion sessions. Thus, the cortico-medial amygdala was concerned with the excitatory system and the basolateral amygdala with the inhibitory system of the rat forebrain. The results of combined unilateral lesions of basolateral and cortico-medial amygdala in each hemisphere suggest that in healthy animals the inhibitory influence of the former was stronger and overlapped or regulated the excitatory action of the latter. Our evidence suggests the existence of two antagonistic systems in the rat amygdala which play different roles in conditioning.

Amygdala↗

Two behavioral paradigms for study of rapid changes in functional grouping of neurons.

Recent progress in extracellular recording technology and in analytic methodology for the resulting spike trains are making practical the simultaneous registration of twenty or more neurons. This begins to make possible the direct experimental observation of functional neuronal assemblies, particularly as they dynamically change in membership or properties during a behavioral task. Behavioral paradigms appropriate for such experiments have very stringent requirements in order, with high likelihood, to produce changes in neuronal assembly structure during the time that stable recording can be maintained. We describe two motor system paradigms that seem to be appropriate, the first with crayfish claw, the second with monkey paw. The crayfish task involves a rapid learning of claw position. The monkey task involves a preset state which determines the responses to a subsequent somatosensory discrimination.

Animals↗

[Importance of appendix stump management in laparoscopic appendectomy].

In laparoscopic appendectomy several variants of technique have been proposed. In a randomized prospective trial we compared three common techniques: 1. application of two endoloops, 2. application of two endoloops and additional manual stump sinking 3. application of endo-cutter. The study included 150 patients, 50 each per technique. The application of two endoloops with additional manual stump sinking as well as the cutter technique were associated with a low risk for complications. In contrast, appendectomy by two endoloops without stump sinking was associated with a higher risk for local complications. The manual stump sinking requires a high level of manual experience, whereas the cutter technique can be learned rapidly by surgical residents. Therefore, we recommend the cutter technique as standard procedure, because it allows laparoscopic appendectomy to be performed with high reliability by experienced surgeons as well as by novice surgical residents.

Appendectomy↗

Hedgehog rehabilitation in perspective.

Thousands of hedgehogs are taken into care each year, mostly injured animals or late-born young unlikely to survive hibernation. Many are returned to the wild, but until recently there was little information about their welfare, behaviour or survival after release. A review of three studies undertaken in different regions of Britain, showed that the majority of 33 released adults and juveniles adapted quickly to life in the wild despite the juveniles having been raised in captivity. They found food readily, made nests and rapidly learned their way about. They all lost weight initially but, after two three weeks, stabilised at a similar weight to wild animals. The hedgehogs which were heaviest at release lost the greatest percentage of their bodyweight, suggesting they had become overweight in captivity. The hedgehogs which were known not to have survived at least six weeks after release included three road casualties and three eaten by badgers. Although wild hedgehogs may die in the same ways, it is possible that the released hedgehogs' susceptibility to such dangers may be increased by their becoming tame during captivity. However, the high survival rate suggests that the release of rehabilitated hedgehogs back into the wild is worthwhile.

Animal Welfare↗

A new model of active avoidance conditioning adequate for pharmacological studies.

A model of rapid learning (active avoidance conditioning), using rats, is described which induces retention depending on the number of trials to which the animals are submitted. For 3 trials (double stimulation) adequately spaced, the memory trace lasts for 48 hr, whilst 6 trails induce a trace for 10 days. One single application of the double stimulation does not give any apparent retention in normal rats for 24 hr. This experimental fact is used to study and screen the activity of substances on the learning process. Animals treated with piracetam, pemoline, methamphetamin, strychnine, pyritinol and meclofenoxate before this single trial, display evidence of retention 24 hr later. Other substances, with known clinical CNS activites, eg, tranquillizers, analgesics, etc... show no positive effect on the mnesic trace.

Animals↗

Two eyes are better than one: superior binocular discrimination learning in pigeons.

Four groups of pigeons each were trained to perform four visual-discrimination tasks of varying difficulty. Two groups received the training binocularly and the other two monocularly. Two types of stimulus displays were used. In one display the two pecking keys were mounted in a horizontal arrangement, whereas, in the other display, the two keys were mounted in a vertical arrangement. In both displays binocular learning was more rapid than monocular learning. This difference increased with problem difficulty. Moreover, training with the horizontal key arrangement resulted in more rapid learning with either viewing condition. These results suggest that the inferiority of monocular learning was not caused by restriction of the visual field along the horizontal plane, and the failure to detect monocular-binocular differences in learning in previous reports may have resulted from inadequate task difficulty. Finally, the results suggest that monocularly-viewing birds should not be regarded as "natural split-brain" preparations.

Animals↗

Animal cognition: how archer fish learn to down rapidly moving targets.

In extremely rapid maneuvers, animals including man can launch ballistic motor patterns that cannot immediately be corrected. Such patterns are difficult to direct at targets that move in three-dimensional space, and it is presently unknown how animals learn to acquire the precision required. Archer fish live in groups and are renowned for their ballistic hunting technique in which they knock down stationary aerial insect prey with a precisely aimed shot of water. Here we report that these fish can learn to release their shots so as to hit prey that moves rapidly at great height, a remarkable accomplishment in which the shooter must take both the target's three-dimensional motion as well as that of its rising shot into account. To successfully perform in the three-dimensional task, training with horizontal motion suffices. Moreover, all archer fish of a group were able to learn the complex sensomotor skill from watching a performing group member, without having to practice. This instance of social learning in a fish is most remarkable as it could imply that observers can "change their viewpoint," mapping the perceived shooting characteristics of a distant team member into angles and target distances that they later must use to hit.

Animals↗

The genetics of learning disabilities.

Rapid progress in the study of learning disabilities requires a common context within which investigators and professionals with very diverse backgrounds can work towards common goals. Much evidence points to the heterogeneity of origin and clinical expression of learning disabilities as well as to many other ways in which they resemble such multifactorial conditions as mental retardation, gout and hypertension. In these conditions, genetic and epidemiological methods have been used to sort out the constitutional and environmental factors which precipitate disease in susceptible persons. Such an approach to learning disabilities can be expected to be rewarding.

Dyslexia↗