Biomedical subjects
J H Wilkinson
Publications and source records attributed to J H Wilkinson.
Lactate dehydrogenase in the diagnosis and assessment of response to treatment of megaloblastic anaemia.
Explore the source record for details and available documents.
Alpha-hydroxybutyrate dehydrogenase activity in sex-linked muscular dystrophy.
In two families with severe sex-linked muscular dystrophy, high levels of alpha-hydroxybutyrate dehydrogenase (HBD), lactate dehydrogenase (LD), aspartate transaminase (AspT), aldolase, and creatine phosphokinase (CPK) were found in the sera of three young affected males. In both families the mother had a raised level of HBD activity. Four sisters of the three affected boys had raised serum enzyme levels, and they are regarded as presumptive carriers of the disease. Biopsy specimens of dystrophic muscle had LD and HBD contents which were significantly lower than those of control specimens, while the HBD/LD ratios were markedly greater. Muscle from two unaffected members of the same family also exhibited high ratios, indicating the presence of the electrophoretically fast LD isoenzymes, and this was confirmed by acrylamide-gel electrophoresis.
Phenolphthalein monophosphate as a substrate for serum alkaline phosphatase. An appraisal.
Explore the source record for details and available documents.
Inhibition of lactate dehydrogenase by sera of uraemic patients.
Explore the source record for details and available documents.
Organ specificity and lactate-dehydrogenase activity. Some properties of human spermatozoal lactate dehydrogenase.
1. The presence of a characteristic lactate-dehydrogenase isoenzyme (LD(x)) in human, mouse and dog testis and in human spermatozoa has been confirmed by electrophoresis on cellulose acetate and on polyacrylamide gel. 2. The human spermatozoal isoenzyme exhibits a much higher affinity for 2-oxobutyrate than any of the five isoenzymes found in other tissues. K(m) values of 0.05mm for pyruvate and 0.18mm for 2-oxobutyrate were obtained. 3. LD(x) differs from other lactate-dehydrogenase isoenzymes in that its properties cannot be correlated with its electrophoretic mobility. It resembles LD(1) in being strongly inhibited by 0.2mm-oxalate and relatively resistant to 2m-urea, and in being relatively stable to heat. 4. The surprisingly high activity of LD(x) with 2-oxobutyrate suggests that this substance or 2-hydroxybutyrate may play a part in spermatozoal metabolism.
Urea and oxalate inhibition of the serum lactate dehydrogenase.
The serum lactate dehydrogenase (LDH) of 16 normal subjects was inhibited by 55 to 68% by the incorporation into the reaction mixture of 0.2 mM-oxalate. Oxalate inhibited the serum LDH of 17 out of 19 patients with myocardial infarction to a greater extent, and that of 16 out of 18 patients with liver disease to a lesser extent than that of the controls. The serum LDH of all 16 patients with liver disease was inhibited by 2 M-urea to a greater degree and that of eight out of nine patients with myocardial infarction to a lesser extent than that of the normal controls (45-62%). The serum LDH of five patients with megaloblastic anaemia was also less sensitive to inhibition by urea than was that of the controls. The inhibitory effect of oxalate was greatest with those sera containing an excess of the electrophoretically fast LDH isoenzymes, while that of urea was most marked with those sera in which the slow LDH isoenzymes preponderated. The results of inhibition studies with urea or oxalate correlated well with other indices of isoenzyme composition. The use of oxalate or urea is recommended as an aid in the enzymatic diagnosis of heart and liver disease, especially when the results of other enzyme tests are equivocal.
A quantitative study of age-related changes in the vascular architecture of the rat cerebral cortex.
A quantitative study of age related changes in the vascular architecture of the rat cerebral cortex is described. A special vessel-filling technique, which allowed the simultaneous fixation of the vasculature, aided the identification of the vessels in histological sections. Vascular parameters, which included the total number of vessel fragments, a blood volume and a vessel wall-surface area index were obtained using a Quantimet 720 shape-analysing computer. In animals aged 13-83 weeks, there was an increase in the above vascular parameters which could mainly be attributed to an increase in the number of vessels with a diameter greater than 8 micrometers. In very old rats, aged 124 weeks, the vascularity of the cerebral cortex was severely reduced. These changes, which are very similar to those reported in the ageing human cerebral cortex, may be explained by either direct or indirect effects on the cerebral vasculature. Possible mechanisms are discussed in relation to similar changes observed in the cerebral vasculature after several different insults.
Quantitative measurement of enzymes.
Explore the source record for details and available documents.
The future of diagnostic enzymology.
Explore the source record for details and available documents.