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Biomedical subjects

D Job

Publications and source records attributed to D Job.

144 records · Page 8Linked to original sources
PubMed1977

Circular dichroism of turnip peroxidases.

Circular dichroic (CD) spectra of two turnip isoperoxidases, P1 and P7, and of their derivatives were measured over the wavelength range of 200 to 650 nm. For the two isoenzymes, it was observed that although the visible and Soret bands are located at similar wavelengths, their ellipticities are different. These results suggest that the active sites are similar but that differences do exist. The results are compared with those reported for Japanese radish peroxidase a and horseradish peroxidase. It appears that a common property of plant peroxidases is the presence of negative CD Soret bands for the reduced forms and their inversion upon cyanide binding. The CD spectra in the far UV region indicate an appreciable helical content for both native enzymes and their various derivatives. The calculated contents of unordered structure are very high (greater than 50% for either P1 or P7), in agreement with other studies on glycoproteins.

Circular Dichroism↗
PubMed1976

Substituent effect on the oxidation of phenols and aromatic amines by horseradish peroxidase compound I.

A stopped-flow kinetic study shows that the reduction rate of horseradish peroxidase compound I by phenols and aromatic amines is greatly dependent upon the substituent effect on the benzene ring. Morever it has been possible to relate the reduction rate constants of monosubstituted substrates by a linear free-energy relationship (Hammett equation). The correlation of log (rate constants) with sigma values (Hammett equation) and the absence of correlation with sigma+ values (Okamoto-Brown equation) can be explained by a mechanism of aromatic substrate oxidations, in which the substrate gives an electron to the enzyme compound I and simultaneously loses a proton. The analogy which has been made with oxidation potentials of phenols or anilines strengthens the view that the reaction is only dependent on the relative ease of oxidation of the substrate. The rate constant obtained for p-aminophenol indicates that a value of 2.3 X 10(8) M-1 S-1 probably approaches the diffusion-controlled limit for a bimolecular reaction involving compound I and an aromatic substrate.

Aniline Compounds↗
PubMed1976

Estrogens, lactation and oral glucose tolerance test in the early puerperium.

An oral glucose tolerance test (OGTT) was performed on 98 women free from any known risk factor of diabetes on the fifth day of the puerperium. Results show that OGTT is greatly influenced by the conditions of lactation. A high proportion of abnormal curves (50%) is found among the group of women receiving estrogens as lactation suppressors at the time of the test. However, in breast feeding women or in non breast feeding women not given estrogen, the proportion of abnormal curves is less than 10%. It is concluded that the unexplained previously reported lack of specificity of the OGTT in the early puerperium could be related to hormonal treatment for lactation suppression.

Blood Glucose↗
PubMed1975

Ventricular compliance and ageing.

Compliance of the right ventricle has been studied in 29 aged subjects who were free from any overt heart failure. The observations indicate that a loss of ventricular compliance results, in aged subjects, in an impairment of diastolic filling, which itself is responsible for a reduction in cardiac output. However, there appears to be no relationship between ventricular compliance and systolic performance but the failure to find any such relation may be due to a contractile adaptation in subjects having a low ventricular compliance.

Adaptation, Physiological↗
PubMedDate not supplied

Diabetic retinopathy, duration of diabetes and risk factors of atherosclerotic cardiovascular disease.

The present study, concerning 145 insulin-dependent diabetics showed positive relationships between the severity of retinal disease on the one hand, and body weight, blood pressure, and serum cholesterol level on the other. These relationships remain significant when the duration of the clinical diabetes and the age of the patient are taken into account. Two interpretations are suggested. They are not incompatible. In diabetic subjects, either the increase in blood pressure and serum cholesterol level causes an aggravation of diabetic retinopathy or there exists a common factor at the origin of retinal lesions and of an increase in risk of cardiovascular disease through atherosclerosis.

Adult↗