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Biomedical subjects

J Charlier

Publications and source records attributed to J Charlier.

At least 37 records · Page 2Linked to original sources
PubMed1992

Acetylornithine deacetylase, succinyldiaminopimelate desuccinylase and carboxypeptidase G2 are evolutionarily related.

The nucleotide (nt) sequence of the Escherichia coli argE gene, encoding the acetylornithine deacetylase (AO) subunit, has been established and corresponds to a 43-kDa (M(r) 42,320) polypeptide. The enzyme has been purified to near homogeneity and it appears to be a dimer consisting of two 43-kDa subunits. The amino acid sequence deduced from the nt sequence was compared to that of the subunit of E. coli succinyldiaminopimelate desuccinylase (the dapE gene product involved in the diaminopimelate pathway for lysine biosynthesis), since both enzymes share functional and biochemical features. Significant similarity covering the entire sequence allows us to infer a common origin for both deacylases. This homology extends to the Pseudomonas sp. G2 carboxypeptidase (G2CP); this or a functionally related enzyme may be responsible for the minor AO activity found in organisms relying on ornithine acetyltransferase for ornithine biosynthesis.

Amidohydrolases↗
PubMed1992

[Evaluation of spatial discrimination performances of newborn infants with the visual pursuit of structured stimuli].

Pursuit eye movements have been recorded with the photo-oculographic technique from newborn infants during the presentation of stimulations specific for spatial discrimination functions. 72.5 per cent of 51 subjects whose eye movements have been recorded have successfully followed stimuli of spatial frequency up to 0.4 cycles per degree. Estimations of grating visual acuity are similar to those provided by the preferential looking technique.

Eye Movements↗
PubMed1992

Visual acuities and scotomas after one week levodopa administration in human amblyopia.

The authors previously showed that a single dose of levodopa improves the contrast sensitivity and decreases the size of fixation point scotomas in amblyopic patients. In the present study, they investigated the effect of levodopa after 1 wk of daily administration using a cross-over, double masked design. The decrease of fixation point scotomas was confirmed with automatic static perimetry. An improvement of visual acuity occurred in 70% of the patients after 1 wk of levodopa administration compared to only 22% in the authors' previous study using one single dose. The improvements in visual acuities and visual fields persisted even after the levodopa administration was completed.

Administration, Oral↗
PubMed1991

Static flicker perimetry in glaucoma and ocular hypertension.

The visual threshold for standard and flickering targets was determined and compared in 8 glaucoma patients, 8 glaucoma suspects and 13 normal controls. Using a Goldmann size III standard white light target, 25 points in the central 30 degrees of the visual field were tested. The location of these points was designed to reflect areas of the visual field commonly affected by glaucomatous damage. The same determinations were then repeated with the test target flickering at 25 Hz. All glaucoma patients had elevation of the visual threshold compared to normal controls for both standard and flickering targets. The absolute value of threshold elevation was not significantly different between standard and flickering lights. However, when larger targets were used, flicker thresholds were an average 8 dB higher (p less than 0.05) in the glaucoma patients compared to the normals, suggesting improved identification of glaucomatous damage with the use of larger flickering targets.

Adult↗
PubMed1990

[A new technic for recording eye movements by image processing. Principle and method].

Nowadays, electro-oculography remains the only clinical method for ocular movement recording which is largely used in daily practise, but it has many drawbacks and limits. Till now the photo-oculographic technics have been only applied in laboratory conditions. A new differential photo-oculographic procedure is presented. This optical method is based upon the measurement of gaze direction and ocular movement amplitude from the relative pattern of five reflected corneal dots and pupil image which are located in two different optical plans. The authors relate in detail the recording devices and processing materials for the computerized analysis of video signals. The preliminary results confirm the real advantages of the method which allows to record all sorts of ocular movements in clinical conditions.

Eye Movements↗
PubMed1990

[Comparative study of electrooculographic and photooculographic recordings].

The authors present the results of clinical application of a new invasive real time method for ocular movement recording. There is an optical system which measures the gaze direction from the video signals of five reflected corneal dots and pupil image. Their study is based upon 110 simultaneous P.O.G. - E.O.G. recordings of normal beings or patients having various oculomotor troubles. It appears that the heavy odds of such a new method is obvious. It allows to obtain an absolute measurement of eye positions in relation to the basic line whatever the pattern and axis of the moving may be. A quantitative evaluation of all movement parameters is in progress. It still remains to solve the problem of large deviations and the wearing of optical correction during the examination.

Electrooculography↗
PubMed1989

[Asymmetry of visual perceptive activity of faces and emotional facial expressions].

Eye movements were studied in 40 right-handed subjects during perception of symmetrical chimerical faces. These movements were recorded using an original system based on a differential optical method for the detection of corneal reflection and of the pupil made shiny. Under basal conditions, the first fixation was usually located in the left visual hemifield. The subjects spent more time gazing at the right hemiface (P less than 0.04). This visuo-spatial asymmetry in favour of the left hemispace was increased when the subject was requested to determine the emotional expressions of a new series of faces (P less than 0.002). Compared with basal conditions, the increase in the percentage of time spent in the left area was significant (P less than 0.035). An analysis performed on the first 3 seconds confirmed and amplified the differences observed. These results can partly be explained by reading habits and exploratory activity for symmetrical shapes. However, activation of the right hemisphere, specialized in the perception of faces and facial expressions, probably influenced visual exploration by drawing attention to the left area and favouring the left visual hemifield.

Adult↗