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Biomedical subjects

J G Cook

Publications and source records attributed to J G Cook.

31 records · Page 2Linked to original sources
PubMed1985

Diabetic ketoacidosis due to insulin resistance treated by haemodialysis.

A 14-year-old female patient with insulin resistance is reported in whom it appeared that initially insulin breakdown was unusually rapid. Subsequently there was in addition evidence of reduced insulin sensitivity. The rapidly increasing requirement of insulin (1600 units daily), given by continuous IV infusion, was dramatically reduced by haemodialysis, and was maintained subsequently. We suggest that insulin aggregates which may have blocked insulin receptor sites, causing insulin resistance, were removed by haemodialysis.

Adolescent↗
PubMed1984

A sensitive method for the measurement of glycosylated plasma proteins using affinity chromatography.

We describe a simple, sensitive affinity technique for the routine measurement of glycosylated plasma proteins in clinical laboratories. The commercially available phenylboronic acid gel used for the chromatography has recently been marketed as a kit for this purpose (Glycogel Test Kit, Pierce Chemical Co). The manufacturers of this kit recommend loading 200 microliters neat plasma to each 1 ml gel column. This high loading is to enable the direct measurement of protein in the bound and unbound fractions at 280 nm. This loading is consistent with 10-15 mg protein being added per ml gel. Our results show that protein levels greater than 2 mg per ml gel overload the column. Therefore we used a modification of the more sensitive Bradford procedure to measure protein. The method discriminates between normals (6.29 +/- 1.87%) and diabetic patients (12.62 +/- 3.36%) and has good precision (CV 4-6%). The results obtained correlate with the colorimetric method using thiobarbituric acid (r = 0.70) and with glycosylated haemoglobin (r = 0.82).

Blood Proteins↗
PubMed1983

Measurement of glycosylated haemoglobins and glycosylated plasma proteins in maternal and cord blood using an affinity chromatography method.

We have used a simple affinity chromatography method to measure total glycosylated haemoglobins and glycosylated plasma proteins in maternal and cord blood at 50 normal deliveries. The affinity method gives equal weighting to glycosylated haemoglobins including haemoglobin F in cord blood. The mean values for glycosylated haemoglobins in maternal blood (6.49 +/- 1.2%) were significantly higher than those in cord blood (3.85 +/- 1.0%; p less than 0.001). The difference with glycosylated plasma proteins was less marked (maternal blood 5.61 +/- 0.9% and cord blood 4.75 +/- 0.6%; p less than 0.001). A contributory factor to these differences was the decrease in glucose concentration from 4.53 +/- 0.99 mmol/l in maternal blood to 3.59 +/- 0.8 mmol/l in cord blood. The results obtained at the birth of six children to diabetic mothers showed the same trends although the mean values for glycosylated haemoglobins (maternal blood 9.27 +/- 2.3%, cord blood 4.21 +/- 0.9%), glycosylated plasma proteins (maternal blood 7.44 +/- 1.6%, cord blood 5.45 +/- 1.7%) and glucose (maternal blood 10.22 +/- 7.3 mmol/l, cord blood 5.18 +/- 3.4 mmol/l) were higher in all samples than for the deliveries to non-diabetic mothers.

Adult↗
PubMed1983

An inexpensive, rapid and precise affinity chromatography method for the measurement of glycosylated haemoglobins.

We have assessed an affinity chromatography technique, using commercially available materials, for the estimation of total glycosylated haemoglobin in the routine clinical chemistry laboratory. The method gives good discrimination between normals (7.31 +/- 0.92%) and diabetics (12.70 +/- 2.88%) and has excellent precision (CV 1.5-2.0%). Labile glycosylated haemoglobin is normally removed as it is so variable. There is no significant correlation between labile glycosylated haemoglobin and blood glucose. Immediate analysis of incubated haemolysates is preferable to storage of haemolysates or erythrocytes. The affinity gel can be reused about 16 times, but oxidation must be reduced by keeping the gel at 4 degrees C in the dark when not in use. The cost of the gel is about 7p a test and 60 samples can be analysed in a working day. The method is not affected by the presence of up to 20% met-haemoglobin and should also give correct values for samples containing genetic variants of haemoglobin.

Anticoagulants↗
PubMed1982

Measurement of glycosylated haemoglobins using an affinity chromatography method.

After removal of the labile material, we have measured the stable glycosylated fraction of haemoglobin with a new, commercially available, phenylboronic acid affinity gel, Glycogel B. The mean value was established for 61 non-diabetics as 7.31 (SD +/- 0.92)% and for 108 diabetics as 12.70 (SD +/- 2.88)%. The method is highly reproducible with a coefficient of variation below 2.0%. The effect of changing the temperature from 7 degrees C to 37 degrees C, and pH from 8.1 to 8.9 was investigated. For accurate results the temperature should be maintained between 20 degrees C +/- 1 degree C, and the pH between 8.6 +/- 0.1. A poor, but significant correlation (r = 0.43) between glycosylated haemoglobin and simultaneous blood glucose was shown. There was a good correlation with the agar gel electrophoretic method (r = 0.95). The slope of the regression line was 1.20 which indicates that this affinity method measures more than just HbA1. The affinity method appears to offer selectivity for diabetics than the electrophoretic method.

Blood Glucose↗
PubMedDate not supplied

Glycosylated hemoglobins and glycosylated plasma proteins in the diagnosis of diabetes mellitus and impaired glucose tolerance.

Total and stable glycosylated hemoglobins and glycosylated plasma proteins were determined on 53 patients referred for a glucose tolerance test. Significant correlations were found with fasting blood glucose (r greater than 0.89), 2-h glucose (r greater than 0.69), and area under the glucose tolerance curve (r greater than 0.75), but the correlations with labile glycosylated proteins were not significant. Thirty-one of the patients were normal, five had impaired glucose tolerance (IGT), and seventeen diabetes mellitus (DM) according to the WHO criteria. Comparison of the glycosylated protein values showed that, in all cases, the values for those with IGT and DM were significantly (P less than 0.001) greater than the values for normals. The range of values of stable glycosylated hemoglobins for those with DM (9.4-24.4%), those with IGT (8.6-10.0%), and normals (5.0-8.5%) shows that there was no overlap between overt diabetic subjects and normal subjects. This was also found for total glycosylated hemoglobins. The results for glycosylated plasma proteins, total and stable, were comparable, but one patient with overt DM and two with IGT had values within the normal range. The measurement of glycosylated hemoglobins and glycosylated plasma proteins by the simple, precise, affinity-chromatography method is potentially a quick, accurate, and simple screening test for patients with DM and IGT and deserves consideration as criteria for their diagnosis.

Blood Glucose↗