PubMed Health⌕ Search

Biomedical subjects

E Azoulay

Publications and source records attributed to E Azoulay.

125 records · Page 7Linked to original sources
PubMedDate not supplied

Isolation and characterization of cytochrome b5 from Candida tropicalis grown on alkane.

Cytochrome b5 from Candida tropicalis grown on alkane has been solubulized in three different ways (sodium cholate, trypsin, osmotic wash). After solubilization of the microsomal membrane with sodium cholate, the purification of cytochrome b5 was achieved by DEAE-cellulose chromatography, hydroxylapatite chromatography, a second DEAE-cellulose chromatography and a Sephadex G-75 gel filtration. The purified protein had an apparent molecular weight of 16 000 +/- 1 000. After solubilization by trypsin treatment or osmotic wash, the purification procedure yielded a protein with an apparent molecular weight of 12 000 +/- 1 000. Though the purified proteins presented molecular weights depending on the technique of solubilization, they exhibited identical optical properties, a great stability with respect to temperature and pH, and were all autooxidable. Redox titrations revealed differences in their midpoint potential values, which were 35 +/- 5 mV for the b5 purified after cholate solubilization, -59 +/- 5 mV for the b5 purified after trypsin treatment and -65 +/- 5 mV for the b5 purified after osmotic wash.

Alkanes↗
PubMedDate not supplied

[Hemoglobin oxygen transport during experimental acute hypercapnia (author's transl)].

The effects on hemoglobin oxygen transport of acute respiratory acidosis have been studied in dogs inhaling a gaseous mixture with 12% CO2 (O2 21%) for two to five hours. In a first series of experiments, it was shown that the shape of the oxyhemoglobin dissociation curve (ODC) was not modified by severe acidosis (pH congruent to 7) lasting for two and a half hours. The Hill number (N equals 2.6) did not change significantly. The aim of the second experimental series was to stuey the Bohr effect and the hemoglobin oxygen affinity (P50). The control value for the respiratory Bohr coefficient (B) was --0.54; neither after two hours (--0.52), nor after five hours of hypercapnia (--0.55) was it significantly modified. The P50 expressed at arterial pH was much increased in acidosis (congruent to 45 torr); when expressed at standard p/ 7.4, it was slightly but significantly decreased (congruent to 1 torr) at the fifth hour. At the same time there was a decrease (p smaller than 0.05) in the erythrocyte 2,3-DPG approaching 15 p. cent; on the other hand the ATP concentration did not change significantly. No significant individual correlation was found between P50(7.4), 2,3-DPG and mean hemoglobin corpuscular concentration. These results suggest that during severe respiratory acidosis neither a change in the shape of ODC, nor a change in Bohr effect do affect the hemoglobin oxygen transport. The main characteristic remains the decrease in oxygen affinity of hemoglobin, due to the erythrocyte [H+] increase induced by hypercapnia ; this phenomenon is observed as long as the 2,3-DPG decrease stays moderate.

Acidosis, Respiratory↗
PubMedDate not supplied

Nitric oxide effects on lung structure and blood oxygen affinity in rats.

Two month-old Wistar rats were exposed continuously for six weeks, either to 2.0 +/- 0.1 ppm nitric oxide (NO) mixed homogeneously with air for tests, or to ambient air for controls. Oxyhemoglobin dissociation curve (ODC), erythrocytic variables, methemoglobin (MetHb) concentration and lung structure, particularly through electron microscopy studies, were investigated each week of exposure. The hemoglobin affinity for oxygen was not modified, probably as a result of both pH and 2,3-diphosphoglycerate (2,3-DPG) stability. Moreover MetHb formation was not found in treated rats. The few ultrastructural alterations found under electron microscopy may not prove NO-induced since they were found similarly in both groups. Slight emphysematous changes were found only in 1 micrometer-thick sections of lungs from NO-treated rats.

Adenosine Triphosphate↗