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Biomedical subjects

N Bradford

Publications and source records attributed to N Bradford.

4 recordsLinked to original sources
PubMed1991

Loss of visual function associated with microalbuminuria in diabetes mellitus: a pilot study.

Visual function loss has been documented in diabetes mellitus in relation to flicker and contrast. However, no direct correlation between the degree of loss in sensitivity and the level of retinopathy has been established. It has been suggested that such non-invasive psychophysical procedures actually reflect metabolic disturbances within the diabetic retina. This study investigates the possibility of whether early nephropathy demonstrated by microalbuminuria, is an indicator of microangiopathy which may be a cause of retinal disturbance leading to a loss of visual function. The visual function of a group of diabetics showing microalbuminuria was studied. Contrast and flicker threshold were measured and the results compared with those obtained with an age-matched control diabetic group. The procedures used effectively separated the two groups and raises the issue of incorporating psychophysics in retinal screening programmes.

Albuminuria↗
PubMed1985

Rat liver glutaminase. Regulation by reversible interaction with the mitochondrial membrane.

Partially purified rat liver mitochondrial glutaminase shows a sigmoidal dependence on glutamine concentration, and an absolute requirement for inorganic phosphate as activator. Reconstitution with a mitochondrial membrane fraction changes the kinetic properties of the enzyme making the glutamine dependence more hyperbolic and reducing the concentration of phosphate required for half-maximum activation. Glutaminase activity in isolated mitochondria is known to be increased as a result of mitochondrial swelling. In mitochondria suspended in isotonic medium, the properties of glutaminase resemble of the isolated enzyme while in swollen mitochondria the kinetic properties revert to those exhibited by the enzyme in association with the mitochondrial membrane. It is postulated that mitochondrial glutaminase is regulated in situ by reversible association with the inner mitochondrial membrane which is mediated by mitochondrial swelling. This mechanism may explain the short-term hormonally induced activation of the enzyme observed in isolated hepatocytes.

Animals↗
PubMed1982

The effect of bacterial peptidoglycans on the immune response of hamsters to influenza virus vaccines.

The immune response of hamsters to influenza virus vaccine incorporating peptidoglycans derived from Streptomyces griseus was investigated. The results showed that although inoculation of a subunit influenza virus vaccine together with a peptidoglycan elicited a markedly increased serum HI antibody response compared to that induced by the subunit vaccine alone, pre-treatment of animals with peptidoglycans resulted in a suppression of the antibody response to the vaccine haemagglutinin antigen. The immunosuppressive effect was dose-related, and could be shown by adoptive transfer experiments to be transferred by spleen cell preparations from peptidoglycan-treated hamsters. The reasons for these findings, and their implication for the use of peptidoglycans as 'carriers' in influenza virus subunit vaccines, are discussed.

Animals↗