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Biomedical subjects

B Zeba

Publications and source records attributed to B Zeba.

5 recordsLinked to original sources
PubMed1998

[Osteogenesis imperfecta diagnoses early, apropos of a case at the Yalgadou Ouédraogo National Hospital Center of Ouagadougou].

Osteogenesis imperfecta which represents a family tragedy for parents, a curiosity for physicians and radiologists, constitutes a real constitutional osteoporosis, usually rare with dominant autosomic transmission. Authors report a case of a 37 week amenorrhea living foetus, presenting an osteogenesis imperfecta. This affection, with early in utero manifestations, has a bad prognosis (baby deceased 72 hours after birth). Diagnosis was suspected at echography and conformed by x-rays investigations. The new born got also clinical and pathological examinations. Authors emphasize the unusualness and the gravity of these early clinical features. They insist on doing echography and radiography for the location of osseous and visceral lesions before and afterbirth.

Fatal Outcome↗
PubMed1996

[Malignant keratoma].

INTRODUCTION: Birth of an Harlequin fetus in an African maternity ward is an exceptional event. There is no question as to the diagnosis, but no treatment is available. CASE REPORT: A female infant was delivered with typical lesions of malignant keratoma. Death occurred 20 hours after birth. DISCUSSION: In countries with adequate intensive care facilities (hydration, acitretine), such infants may occasionally survive with the risk of developing major lamellar ichthyosis which remains a handicap for the rest of life. In Burkina-Faso, such therapeutic facilities are lacking as are means of antenatal diagnosis. The ethical question as to whether or not to attempt survival measures is quite different under these conditions.

Burkina Faso↗
PubMed1980

Peroxidase content of soybean root nodules.

A peroxidase has been isolated from soybean nodules and its main characteristics have been determined. Its molecular weight (48 000) and spectral properties are similar to those of usual plant peroxidases. Its activity is comparable to that of low-efficiency plant peroxidases. The rate constant of the reaction with H2O2 is 3 x 10(5) M-1 x s-1. In this reaction, nodule peroxidase yields an oxidized intermediate analogous to the compound I species of peroxidases already studied. A comparison is made with the pseudoperoxidatic activity of soybean leghemoglobin components. Leghemoglobins a and c react with H2O2 with rate constants of 5 x 10(3) and 2.5 x 10(3) M-1 x s-1, respectively, yielding the leghemoglobin (IV) species. During these reactions leghemoglobins are inactivated.

Kinetics↗
PubMed1980

Kinetic studies of the reaction of ferric soybean leghemoglobins with hydrogen peroxide, cyanide and nicotinic acid.

A kinetic study of the reaction of two soybean leghemoglobins (components a and c) with hydrogen peroxide to form the oxidized compound (leghemoglobin IV) has been carried out over the pH range 2.5--10. Three different ionization processes of leghemoglobins with pKa values of 3,4.7 +/- 0.2 and 8.2 +/- 0.1 are required to explain the rate/pH profiles. Protonation of the former group and ionization of the latter cause a decrease in the rate of reaction of the hemoproteins with H2O2. The results are compared to those obtained for the reactions of plant peroxidases and myoglobin with H2O2. The results obtained from the kinetic study of cyanide binding to soybean leghemoglobins indicate that CN- is the reactive species. Two ionization processes of leghemoglobins with pKa values of 4.7 +/- 0.2 and 8.2 +/- 0.1 affect the reaction rates. The association and dissociation rate constants corresponding to nicotinic acid binding to leghemoglobins a and c have been measured over the pH range 2.5--7. The dissociation rate constant is affected by ionization of a group with pKa less than 2.5 for both leghemoglobin-nicotinate complexes. In this pH range the association rate constant is only affected by ionization of a group with pKa value of 4.7 +/- 0.2. The analysis of these results shows that both ionization processes corresponding to ring nitrogen atom of the ligand (pKa approximately equal to 4.9) and to a heme-linked group (pKa approximately equal to 4.7 +/- 0.2) influence the association rate constant. Furthermore, it appears that in the binding site of leghemoglobins the pKa value corresponding to ionization of the ring nitrogen atom of nicotinic acid is shifted from the normal value of 4.9 to a value of less than 2.5. This pecularity might explain the exceptional reactivity of leghemoglobins for nicotinic acid, over a large pH range. For both cyanide and nicotinic acid binding reactions, the ionizable group of leghemoglobins with pKa value of 4.7 +/- 0.2 seems to act as an electrostatic gate. When the group is deprotonated, it restricts the access of anion ligands to the heme pocket. For all the three reactions studied, leghemoglobin a reacts about twice as fast as leghemoglobin c.

Cyanides↗