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At least 217 records · Page 12Linked to original sources
PubMed2003

[Fiberoptic intubation in adult patients with predictive signs of difficult intubation: inhalational induction using sevoflurane and an endoscopic facial mask].

OBJECTIVE: To evaluate the combination of inhalational induction with sevoflurane and fiberoptic intubation through a specific facial mask for anticipated difficult tracheal intubation (DI) in adults. STUDY DESIGN: Prospective study. PATIENTS AND METHODS: Eighteen consecutive patients at risk of DI. After premedication made of hydroxyzine 2 mg x kg(-1), preoxygenation, 0.1 microg x kg(-1) sufentanil was administered (T0), then, inhalational induction was started: sevoflurane 8% in 100% O2 l x min(-1). After 1 min, sevoflurane was decreased to 5% and, if necessary, adapted to obtain an adequate depth of anaesthesia (Ramsay score > 3). Fiberoptic bronchoscopy was performed through a Fibroxy mask. BP was measured every 2.5 min, HR, SpO2, RR were recorded. The results were analyzed by Newman-Keuls test. RESULTS: Intubation was easily realized but it was necessary to assist ventilation in patients presenting prolonged apnea lasting more than 30 s (5 out of 9 patients who presented apnea during procedure). Intubation was quickly realized (T+ 4 +/- 3 min). Haemodynamics and saturation were not altered during procedure. Inhalatory induction using sevoflurane costs 6 10 versus 16 80 for intravenous target controlled propofol anesthesia (using only one preconditionned syringe). CONCLUSION: Inhalational induction with sevoflurane and fiberoptic intubation appeared easy, fast and cheap.

Adult↗
PubMed2003

Free amino acids in the clam Macoma balthica L. (Bivalvia, Mollusca) from brackish waters of the southern Baltic Sea.

Fourteen acidic and neutral free amino acids (FAA) were investigated in soft tissue of Macoma balthica from different depth zones of the Gulf of Gdansk (Baltic Sea) over a full seasonal cycle. The dry weight of the bivalves and physico-chemical parameters of overlying bottom water and surface sediments were measured simultaneously at each site. In the brackish waters of the Baltic, the main pool of FAA is composed of Ala, Gln, Arg, Gly and Orn which represent approximately 80% of the total. Compared to the full saline environments, the composition of FAA in the clams from the Baltic differs substantially. The differences can be attributed to the lower salinity of the Baltic. In the Baltic, Gly appears to play a most important role in regulating intracellular osmolarity in the clams, a function performed primarily by Tau in Atlantic and North Sea populations. Spatio-temporal variations of the FAA are affected by biotic and environmental parameters; their respective influence differs with the amino acids. The concentration of Arg depends on its uptake from the external medium. However, its level might be temporarily modified by stress-induced metabolic transformation (e.g. hydrolysis to Orn) caused by changes in the ambient environment. The concentration of Ala increases with depth, probably because of physiological adaptations of the animal to diminishing oxygen concentration through anaerobic glucose catabolism. Biosynthesis of Ala, similarly to Gln, in the shallower zone is generally related to the physiological state of an organism. The concentration of Gly is most likely regulated by internal mechanisms driven by gonadal development and reproduction.

Alanine↗
PubMed2000

3-D vision improves performance in a pelvic trainer.

BACKGROUND AND STUDY AIMS: Experienced endoscopic surgeons have adapted to the absence of depth perception while using two-dimensional (2-D) visualization. However, three-dimensional (3-D) vision may prove useful at least at the beginning of the learning curve in celioscopic training. METHODS: In a pelvitrainer with a fixed camera, two skill tests were designed to assess the performance of three groups of operators: "non-surgeons", "non-celioscopist surgeons", and "trained celioscopists". In the first test, the candidate had to touch with a needle a sequence of dots distributed on a 7.1-cm2 area. In the second test, a 6-0 C-1 needle had to be passed consecutively through two 1-mm holes made in a thin vertical plastic wall. Each test was performed ten times, using either 2-D vision (five times) or 3-D vision (five times) interspersed in a random manner. RESULTS: In both tests and within each group, performance was related to the experience of the operator, with the trained celioscopists' group obtaining the best results and the non-surgeons the worst. In every situation, including the trained celioscopists' group, 3-D vision significantly improved performances. No significant difference was observed between the results of the non-celioscopist surgeons' group using 3-D vision and those of the trained celioscopists' group using 2-D vision. CONCLUSIONS: 3-D vision improves the performance and accuracy of endoscopic surgeons. It provides a visual perception "close to reality", and helps celioscopic beginners to accelerate their training.

Adult↗
PubMed1987

Effect of target size on anomalous sensory responses in the Bagolini striated lens test.

Different results obtained by different methods of retinal correspondence testing are generally accepted to be a sign of the depth of the anomalous sensory adaptation. The Bagolini striated lens test is considered a standard "natural" test to which others are compared. In this study, the Bagolini striated lens test was performed on 25 strabismic subjects using three target sizes in order to determine if target size might be a factor in response variability. Kappa Measure of Agreement, used to analyze the results statistically, showed a moderately high to high level of agreement among the three targets. This indicates that practitioners can feel confident of consistent test results on the striated lens test using any of the three readily available target sizes selected. A brief literature review has been provided as a guide to the theories of strabismus and correspondence and to emphasize the purpose of this research.

Child↗
PubMed2004

The coriotome--a new hand-held device for trimming of skin grafts.

BACKGROUND: Skin grafts require a meticulous removal of subcutaneous fat from their underside to ensure their survival at the recipient site. Often a dermal layer is trimmed as well to improve the take of a skin graft or to adapt its thickness to the depth of a defect. OBJECTIVE: The authors present a new hand-held surgical device, the coriotome, that permits trimming a skin graft more evenly and in a considerably shorter period of time than by applying the conventional method using surgical scissors or a scalpel. RESULTS: A total of 154 skin grafts (98 from preauricular, 45 from supraclavicular, and 11 from inguinal donor sites) were trimmed with the coriotome to a desired thickness. In 2 cases minor lacerations (<3 mm) of skin grafts occurred as a result of an inappropriate use. CONCLUSION: The coriotome permits a fast and safe trimming of skin grafts.

Humans↗
PubMed1975

Intrinsic renal disease leading to abnormal urate excretion.

Since approximately two thirds of daily urate production is normally excreted by the kidney, intrinsic renal disease resulting in abnormalities of urate excretion may have a profound effect upon urate homeostasis. Alterations in the pattern of urate excretion encountered in chronic renal failure are reviewed in depth, with a description of adaptive mechanisms for urate excretion which develop in residual nephrons, as exemplified by the remaining normal kidney of transplant donors. In addition, abnormalities in urate excretion in the presence of a normal complement of nephrons are described. Diminished urate excretion per nephron appears to be responsible for hyperuricemia in some patients with gout, while a variety of tubular defects resulting in excessive renal urate excretion have been documented as the basis for some cases of hypouricemia.

Acute Kidney Injury↗
PubMed1993

Concentrations, metabolic clearance rates, production rates and plasma binding of cortisol in Antarctic phocid seals.

We have reported previously that plasma of the Weddell seal, a member of the phocid family, contains a very high concentration of cortisol. The present study was undertaken to determine whether high cortisol levels were common to seals in the Antarctic environment, or to other phocidae, and to determine the mechanism of the hypercortisolaemia. High levels of cortisol (0.82-2.38 mumol/l) were found in 4 phocidae (Weddell, crabeater, leopard and Southern elephant seals), whereas levels in a member of the otariid family (Antarctic fur seal) were similar to human values. Metabolic clearance rates (MCR) and production rates (PR) of cortisol were determined in the field in Weddell (N = 1), crabeater (N = 3) and leopard (N = 3) seals following bolus injections of [3H] cortisol. The MCR and PR did not differ between the three phocids, but whereas the MCR of 410-590 1/day was twice that of human values, the PR of 460-1180 mumol.m-2 x d-1 was up to 40-fold greater. The binding capacity of corticosteroid-binding globulin (CBG) was equal to or greater than the plasma concentrations of cortisol, resulting in relatively low concentrations of free cortisol. We conclude that hypercortisolaemia is maintained in phocid seals mainly by a high production rate--the highest (corrected for surface area) reported in any species. The relatively low cortisol levels in otariid seals studied in the same environment suggest that the high PR in phocidae is unrelated to the harsh climatic conditions, but may be part of their adaptation for diving to extreme depths.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

[What do you actually see? Visual impairments and their simulation for well-seeing subjects].

Most physicians know little about how persons with limited vision perceive something. Sometimes, simple technical aids can make it possible to get an idea as to what a visual disorder means to the person involved. Examples of this are the wearing of glasses of varying positive power and light transmittance, or the study of case histories, paintings and photographic simulations. Among the latter are a woman who painted what she 'saw' with her removed eye, an anophthalmic man who painted from memory, and the painting of a protanopic artist who chose colours by reading the labels on the paint tubes. Thus one may gain insight in disturbances such as phantom images, diminished visual acuity and visual field loss, metamorphopsia, diplopia, dazzling, and visual agnosia. And also in disturbed image fusion, in depth and stereoscopic vision, dark adaptation and colour vision, as well as diminishing visual functions at high age. This article contains colour illustrations that simulate the disturbances.

Aging↗
PubMedDate not supplied

[Microsporidians of the genus Myxidium in rattail fish from the North Atlantic and the Pacific Ocean].

In contrast to macrurids from the Pacific, for which 5 species of myxosporidia of the genus Myxidium are known, only one species, M. coryphaenoidium, is recorded for this group of fishes from northern Atlantic. In 9 of 13 species of macrurids there were found M. melanostigmum, M. melanocetum, M. noblei sp. n., Myxidium sp. M. coryphaenoidium, the diagnosis of which is rather wider and includes the parameters of other species, was not found. The spores found have a large size, rough polar filament, flattened ends of spores and unequal polar capsules. This favours apparently the sinking of spores to a considerable depth and so is an adaptation for parasitism in deepwater fishes.

Animals↗
PubMed1997

Dual multiple-scale processing for motion in the human visual system.

A number of psychophysical and physiological studies have suggested that first- and second-order motion signals are processed, at least initially, by independent pathways, and that the two pathways both consist of multiple motion-detecting channels that are each narrowly tuned to a different spatial scale (spatial frequency). However, the precise number and nature of the mechanisms that subserve first- and second-order motion perception in human vision remain both controversial and speculative. We sought to clarify this issue by conducting selective adaptation experiments, in which modulation-depth thresholds for identifying the direction of stimulus motion of first-order (luminance-defined) and second-order (contrast-defined) drifting gratings were measured both prior to and following adaptation to motion. The drift direction, spatial frequency and stimulus type (either first- or second-order) of the adaptation and test stimuli were systematically manipulated. When the adaptation and test stimuli were either both first-order gratings or both second-order gratings, robust elevations of direction-identification thresholds were found and, importantly, these aftereffects exhibited both direction-selectivity and spatial-frequency selectivity. Cross-over-adaptation effects between first- and second-order gratings were also sometimes observed, but were very weak and not spatial-frequency selective. These findings give direct support for the existence of multiple-scale processing for first- and second-order motion in the human visual system and provide additional evidence that the two varieties of motion are initially processed by independent pathways.

Adaptation, Ocular↗
PubMed1989

[Fatigue strength and marginal adaptation of composite fillings].

Threshold load tests have shown that the fatigue strength of Class I composite fillings may be increased up to 150 N by the application of a base material. This effect varied only with the consistency of the composite, not with the type of base material used. However, differences were found in the depths at which losses of marginal adaptation occurred: where glass ionomer cement base (polyalkenoate) was used, marginal leakage demonstrated by pigment penetration tests stopped at the interface between filling and base, while in those cases where phosphate cement was used as base material, pigment penetration was shown to extend down to the floor of the cavity. Mesiodistal sections through Class II MOD restorations with the same combinations of materials after 24 hours of storage in pigment solutions and without loading revealed that a close marginal fit in the area of the cervical step can be obtained with the use of glass ionomer cement as base material. In contrast to this observation the use of phosphate cement as base material is associated with marginal leakage down to the area of the floor of the cavity in about one half of the restorations.

Composite Resins↗
PubMed1993

On the perceptual identity of dynamic stereopsis and kinetic depth.

This paper presents a set of experiments demonstrating novel interactions between kinetic depth (depth-from-motion) and dynamic stereopsis (depth-from-disparity). Previous research has shown that adaptation to a moving stereoscopic figure influences the subjective percept of a subsequently viewed kinetic depth figure. In this paper the interactions between kinetic depth and dynamic stereopsis are shown to be very robust and to occur in situations involving perceptual priming. It is also found that kinetic depth and dynamic stereo stimuli are indistinguishable when the stereoscopic stimulus has small, but perceptually salient, disparity. These results are consistent with the hypothesis that stimuli for kinetic depth and for dynamic stereopsis engage a common neural network.

Depth Perception↗
PubMed1996

Enterocytic gene expression in intestinal adaptation: evidence for a specific cellular response.

After massive small bowel resection, the remnant gut epithelium undergoes an adaptive response marked by an increase in villus height, crypt depth, and crypt cell production rate. Although morphological features of gut adaptation have been well characterized, the differentiation status and response of epithelial cells populating the adaptive villus is unclear. To address these issues, cell-specific and spatial patterns of expression of a set of enterocytic genes were characterized in rats after 70% small bowel resection. The liver and intestinal (I) fatty acid binding protein (FABP) and apolipoprotein A-I (apo A-I) and apo A-IV genes were studied because they exhibit unique regional and cell-specific patterns of expression in the developing and adult gut. At 48 h after surgery, apo A-IV and I-FABP mRNA levels were increased up to 3.5-fold in adaptive remnant ileum compared with sham-operated or sham-resected control ileum. In situ hybridization and immunohistochemical analyses revealed a marked increase in enterocytic apo A-IV mRNA and protein expression in the adaptive ileum, from villus base to tip but not in crypts. By 1 wk after resection, apo A-IV, but not I-FABP, mRNA levels remained elevated in remnant ileum, although duodenal I-FABP mRNA levels were still increased. In contrast, apo A-I mRNA levels were not significantly induced. These results indicate that the enterocyte can respond acutely to loss of small bowel surface area by increasing expression of several genes. This compensatory enterocytic response is spatially (from duodenum to ileum) and temporally regulated. These results suggest initiation of the adaptive response occurs by way of a complex set of molecular pathways involving villus and crypt cells.

Adaptation, Physiological↗
PubMedDate not supplied

Crestal bone resorption 5 years after implant loading: clinical and radiologic results with a 2-stage implant system.

PURPOSE: The aim of the present study was to assess crestal bone resorption 5 years after loading by conducting a clinical and radiographic evaluation of 112 Frialit-2 implants consecutively placed in 51 patients from January 1994 through June 1994. MATERIALS AND METHODS: All implants were placed in the same private-practice clinic by the same surgeon. Clinical assessment included plaque score monitoring, bleeding on probing, probing depth, type of occlusion, and prosthetic adaptation. Intraoral radiographs were taken and compared using suitable software to accurately measure peri-implant bone resorption. RESULTS: The survival rate of the implants was 100%. Plaque was present on 47 (42%) implants. Bleeding on probing was detectable at 17 implants (15.5%). Probing depth was > 5 mm for 5 implants (4.5%). Crestal bone resorption was > 3 mm for 32 implants (28.6%); the average observed crestal bone resorption was 2.17+/-1.6 mm. DISCUSSION: The survival rate of the implants may be the result of the relatively short functional period as well as the strict and frequent clinical evaluations associated with oral hygiene procedures during the supportive periodontal therapy. CONCLUSION: The results suggest that with strict plaque control, and provided that the patient follows a regular program of supportive therapy, crestal bone resorption around a 2-stage implant system may be limited.

Adolescent↗
PubMed2006

Motion aftereffects specific to surface depth order: beyond binocular disparity.

Despite evidence for concurrent processing of motion and stereopsis from psychophysics and neurophysiology, the detailed relationship between depth and motion processing is not yet clear. Using the contingent aftereffect paradigm, we investigated how the order of surfaces presented across depth influenced motion perception. After having observers adapt to two superimposed populations of dots moving in opposite directions at different binocular disparities, we assessed how much of the motion aftereffect (MAE) was specific to absolute disparity and how much was specific to the depth order of the surfaces. The test contained two planes of moving dots at several different pairs of disparities and asked observers to report the MAE direction at one of the planes (the target). In addition to the disparity-contingent MAE (Verstraten, Verlinde, Fredericksen, & van de Grind, 1994), we found MAEs dependent on surface order. When the target surface was in front of another surface, observers more often reported the MAE in the direction opposite to the front adapting surface than the back. This effect was observed despite differences in absolute and relative disparity between the adapted and test surfaces. The results suggest that some motion information is represented in terms of surface depth order.

Adult↗
PubMed2004

Generalized parallel-perspective stereo mosaics from airborne video.

In this paper, we present a new method for automatically and efficiently generating stereoscopic mosaics by seamless registration of images collected by a video camera mounted on an airborne platform. Using a parallel-perspective representation, a pair of geometrically registered stereo mosaics can be precisely constructed under quite general motion. A novel parallel ray interpolation for stereo mosaicing (PRISM) approach is proposed to make stereo mosaics seamless in the presence of obvious motion parallax and for rather arbitrary scenes. Parallel-perspective stereo mosaics generated with the PRISM method have better depth resolution than perspective stereo due to the adaptive baseline geometry. Moreover, unlike previous results showing that parallel-perspective stereo has a constant depth error, we conclude that the depth estimation error of stereo mosaics is in fact a linear function of the absolute depths of a scene. Experimental results on long video sequences are given.

Aircraft↗
PubMed2005

Seeing motion in depth using inter-ocular velocity differences.

An object moving in depth produces retinal images that change in position over time by different amounts in the two eyes. This allows stereoscopic perception of motion in depth to be based on either one or both of two different visual signals: inter-ocular velocity differences, and binocular disparity change over time. Disparity change over time can produce the perception of motion in depth. However, demonstrating the same for inter-ocular velocity differences has proved elusive because of the difficulty of isolating this cue from disparity change (the inverse can easily be done). No physiological data are available, and existing psychophysical data are inconclusive as to whether inter-ocular velocity differences are used in primate vision. Here, we use motion adaptation to assess the contribution of inter-ocular velocity differences to the perception of motion in depth. If inter-ocular velocity differences contribute to motion in depth, we would expect that discriminability of direction of motion in depth should be improved after adaptation to frontoparallel motion. This is because an inter-ocular velocity difference is a comparison between two monocular frontoparallel motion signals, and because frontoparallel speed discrimination improves after motion adaptation. We show that adapting to frontoparallel motion does improve both frontoparallel speed discrimination and motion-in-depth direction discrimination. No improvement would be expected if only disparity change over time contributes to motion in depth. Furthermore, we found that frontoparallel motion adaptation diminishes discrimination of both speed and direction of motion in depth in dynamic random dot stereograms, in which changing disparity is the only cue available. The results provide strong evidence that inter-ocular velocity differences contribute to the perception of motion in depth and thus that the human visual system contains mechanisms for detecting differences in velocity between the two eyes' retinal images.

Adaptation, Physiological↗