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Biomedical subjects

D Tortrat

Publications and source records attributed to D Tortrat.

8 recordsLinked to original sources
PubMed1989

Cholesterol as risk factor for mortality in elderly women.

92 women aged 60 years and over (mean 82.2, SD 8.6) living in a nursing home and free from overt cancer were followed-up for 5 years. 53 died during this period; necropsy revealed cancer in only 1 patient. Serum total cholesterol at entry ranged from 4.0 to 8.8 mmol/l (mean 6.3, SD 1.1). Cox's proportional hazards analysis showed a J-shaped relation between serum cholesterol and mortality. Mortality was lowest at serum cholesterol 7.0 mmol/l, 5.2 times higher than the minimum at serum cholesterol 4.0 mmol/l, and only 1.8 times higher when cholesterol concentration was 8.8 mmol/l. This relation held true irrespective of age, even when blood pressure, body weight, history of myocardial infarction, creatinine clearance, and plasma proteins were taken into account. The relation between low cholesterol values and increased mortality was independent of the incidence of cancer.

Aged↗
PubMed1988

Maternal-fetal transfer of fluoride in pregnant women.

Gas chromatography was used to measure the maternal and fetal plasma inorganic fluoride values at term in 91 women. They were assigned to one of four groups: group A were untreated controls; group B received a single daily dose of 1.5 mg of fluoride (as calcium fluoride) during the final trimester of pregnancy; group C was given a single dose of 1.5 mg of fluoride (as sodium fluoride) and group D was given 2 daily doses of fluoride (as sodium fluoride) totaling 1.5 mg. There was a significant difference between the cord plasma fluoride levels of the newborns in the untreated group (mean: 27.8 micrograms/l) and that of the combined supplemented groups B, C and D (mean: 58.3 micrograms/l). There was no difference between the average fluoride levels in the three supplemented groups. There was no significant effect of maternal age, infant birth weight, gestation or diet during pregnancy on the cord plasma fluoride level. These results indicate that fluoride supplementation during the final trimester of pregnancy will significantly elevate cord plasma fluoride concentrations.

Adult↗
PubMed1986

[Preliminary study on transplacental transfer of fluoride. Apropos of 41 mother-infant couples].

Comparing the levels of ionised fluoride in the serum of maternal blood at the time of delivery and cord blood shows that there is a good correlation between the two levels (r = 0.66). This makes it possible to say that fluoride is transferred easily across the placenta. The transfer is not influenced by the parity of the age of the mother nor by epidural anaesthesia, nor by the Apgar score. It does, however, correlate with the duration of the pregnancy.

Adolescent↗
PubMed1985

[EEG mapping during a visuo-spatial task. Averaged maps and group statistics].

Twenty young volunteers (10 men, 10 women), righthanded, students, have been recorded in EEG cartography in different situations. We have compared the quantified EEGs when the subjects were resting, eyes closed and later, eyes opened, looking at a cartoon. The EEGs were quantified by spectral Fourier analysis and submitted to data reduction. Ten spectral parameters were computed, yielding 51 variables allowing computations and drawings of 90 EEG maps. Mean parameters, mean variables, averaged EEG maps have been computed for the entire group, between sub-groups, between hemispheres. Non-parametric permutation Fisher tests have been applied for statistical comparisons and statistical validations of the EEG maps computed between subjects. The activation of EEG tracings produced by the opening of the eyes were caracterized topographically by: mean alpha frequencies increased over temporal and rolandic areas; mean alpha amplitudes in microV divided by a factor 3 for occipital areas but unchanged in topography; mean relative amplitudes divided by a factor 2 but with a topography being more parietal than occipital for the alpha rhythm; a resonance coefficient greater over the left parietal than the right (alpha more regular), whereas it was greater over the right occipital than the left during the resting condition. Statistically for the whole group, the left hemisphere, recorded after the right, is more 'activated' in the eyes closed situation. During visual attention, the left hemisphere is less activated than the right.

Adult↗
PubMed1985

Electroencephalographic cartography. II. By means of statistical group studies-activation by visual attention.

10 male volunteers, right-handers, mean age 30.4 years, were recorded in four successive sequences: under 'eyes closed' conditions, right and then left hemisphere, followed by an 'eyes open' situation with visual attention fixed on a cartoon, right and then left hemisphere recordings. Each EEG recording was made simultaneously over 16 EEG channels for each hemisphere, according to a protocol previously described as well as Fourier analysis and EEG mapping on a minicomputer (HP 5451 C, HP 1000). Each EEG recording was stored on a cartography data base, and 90 maps could be drawn from 10 spectral parameters applied to the raw EEG and 5 frequency bands. Permutation paired Fisher tests were applied to three main EEG parameters: mean centroid frequencies, RMS amplitudes in microvolts and relative (%) amplitudes. Activation of EEG in the 'eyes open' situation during visual fixation was found compared to the 'eyes closed' situation: decreasing dominant EEG frequency and low delta and theta mean frequencies, no change in a mean alpha frequency; increasing fast mean beta frequencies, together with a major decrease in theta, alpha, beta 1 amplitudes, and a concomitant increase in raw EEG, delta and beta 2 amplitudes. Finally, the percent alpha amplitude was decreased when other percent amplitudes were increased in delta, theta, beta 1 and beta 2 frequency bands. A symmetry between hemispheres was observed in the 'eyes closed' situation. Averaged EEG maps between subjects illustrate these findings, especially relative (%) alpha amplitude maps and also maps of coefficients of resonance of the alpha rhythm.

Adult↗
PubMed1984

Computerized topo-EEG spectral maps: difficulties and perspectives.

An electric potential measurement tells us only about the difference between two electrode locations. When prior experiments or present measurements prove that an electrode's location is inactive (especially in 'mono-polar' or scalp-to-reference technique), then EEG records and EEG maps can be interpreted regionally near each electrode location. Topographical mapping requires spatial interpolation which is one factor involved in spatial resolution. The interpolation algorithm has been studied by changing the power exponent n of the interelectrode distance d. When n is close to zero, interpolated values are all equal to the average of the four electric potential measurement Vs bounding the quadrilateral in which the interpolated points of the EEG map are located. When n is very high (n = 20 or higher), the values are essentially equal to the V which is at the minimum distance d. For n = 1, the map seems unlikely to represent the true scalp field. The choice between n = 2 and n = 3 is difficult, but n = 3 EEG mapping looks better (more plausible) and is our regular choice. The choice of recording/reporting method has also been studied. If the quantitative EEG map is linearly calculated from observations, the interpretation of record activity resulting from charge separation near the non-reference electrode attached to a particular channel is only possible when inactivity can be assured. This is completely different when the quantity mapped is not linearly calculated from observations (like power values or rms amplitudes in microvolts).(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Mapping↗