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Biomedical subjects

L Hamzaoui

Publications and source records attributed to L Hamzaoui.

6 recordsLinked to original sources

Ex vivo discrimination between normal and pathological tissues in human breast surgical biopsies using bioimpedance spectroscopy.

Ex vivo bioimpedance data measured on normal and cancerous female breast tissues are reported. They clearly show that the electrical properties of normal tissues, surrounding tissues, and carcinoma are different. These differences lie in the conductivity, in the characteristic frequency (frequency of the maximum of the imaginary part of the bioimpedance), and also in the shape of the Bode plots. Modeling using an R-S-Zcpe model is reported as well as indexes extracted from the real and imaginary parts of the bioimpedance. Even if a classification of the different types of tissues remains a difficult task and leads to much less precise diagnosis than microscopic examination, the electrical behavior of mammary tissue could be used to develop a noninvasive technique for early breast cancer detection.

Biopsy↗

Parametric modelling for electrical impedance spectroscopy system.

Three parametric modelling approaches based on the Cole-Cole model are introduced. Comparison between modelling only the real part and modelling both the real and imaginary parts is carried out by simulations, in which random and systematic noise are considered, respectively. The results of modelling the in vitro data collected from sheep are given to reach the conclusions.

Animals↗

In vitro tissue characterization and modelling using electrical impedance measurements in the 100 Hz-10 MHz frequency range.

In vitro electrical impedance spectrometry was performed on tissue samples excised from sheep. Measured data have been processed to reduce dispersion in measurements and to provide criteria useful for tissue comparison. Two electrical models are proposed for tissues exhibiting a one-circle impedance locus and a two-circle impedance locus. Measurement results and electrical parameters of tissues and models fitted to experimental data are presented. Model sensitivity to parameter variations is discussed.

Animals↗

Tissue characterization by impedance: a multifrequency approach.

Two experimental set-ups for in vitro characterization of electrical bio-impedance are described. The first one, based on a commercially available instrument, operates in the frequency range 1 Hz-10 MHz. The second one uses an identification process and operates in the frequency range 1 Hz-1 MHz. Some results are presented and discussed in the context of multifrequency electrical impedance tomography.

Animals↗

[Difference albumin-transferrin interest in the iron deficiency detection in a cohort of 1288 schoolchildren in the district of Tunis].

Iron deficiency (ID) is the most common nutritional deficiency worldwide especially among young children, women in pregnancy and breastfeeding. This study was undertaken to assess the prevalence of ID in 1288 pupil ranging in age from 11 to 14 years. Haemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), serum iron (Fe) serum transferrin (Trf), serum ferritin (Ft) and an inflammtory proteic profil (IPP) were measured. The IPP combines the analysis of protein variations: protein results are converted in percent of normal values referenced for the technique used. It has been suggested that on the protein profile, an increase in serum transferrin level compared to a normal serum albumin level (DAT: difference albumin-transferrin), appears early in the course of ID. Iron deficiency was defined by a low serum ferritin (< 15 ng/mL) and/or a pathologic DAT (> 28%). Approximately, 33.8% of children had Ft < 15 ng/mL and 12,8% had DAT > 28% while ferritin values were in the normal range. Diagnosis performance (sensitivity, specificity and diagnosis efficacy) of ferritin and DAT were compared to the performance of high serum transferrin receptor (sTfR) values in 2 populations presenting or not a biological inflammation. Only the diagnosis efficacy of DAT was constant in both situations. In conclusion, the serum ferritin concentration is the first indicator of body storage iron identifying ID, however normal or elevated values of ferritin may be difficult to interpret particulary in the presence of inflammation. sTfR and DAT values are thus reliable indicators of ID in such circumstances.

Adolescent↗