Biomedical subjects
C A Pennock
Publications and source records attributed to C A Pennock.
A collaborative study of the measurement of glycosylated haemoglobin by several methods in seven laboratories in the United Kingdom.
A collaborative study compared methods for measuring glycosylated haemoglobin in seven laboratories in the United Kingdom. No satisfactory standard for general use was found. Satisfactory internal quality control systems were in use for each assay which allowed the maintenance of a normal range in each participating laboratory. No satisfactory quality control system suitable for general use could be identified. Costs and convenience of the assays are reported. The technical problems with each type of assay and precautions for their use were identified, such as the need for standardization in incubation times, the practicability of automation of colorimetric assays, and the precision of pH needed for buffers in column separation methods. The relevance of the technical problems to interpretation of measurements is also considered. It is concluded that laboratories measuring glycosylated haemoglobin should maintain a normal range, use 'in-house' quality controls to monitor assay performance and keep clinical colleagues informed of the findings and of any changes in methodology that might affect the interpretation of results.
Mannosidosis in two brothers: prolonged survival in the severe phenotype.
Two cases of mannosidosis are reported in brothers, one aged 41 years at death, the other aged 40 years and still alive. These patients are the oldest reported in the literature. Prolonged survival has previously been associated with the milder Type II phenotype. In addition to the characteristic clinical and radiological features of mannosidosis, both had severe joint destruction, which may be related to abnormal lysosomal enzymes in cartilage. The activity of acidic alpha-mannosidase was markedly reduced in plasma, leucocytes and fibroblasts, and the altered kinetic and physical properties are described.
Impact of home blood glucose monitoring on childhood diabetes.
Ninety diabetic children each provided at least one 24-hour blood glucose profile at home using an impregnated filter paper strip. The mean 24-hour blood glucose level correlated significantly with urine control, height velocity, and Hb A1. The correlation coefficient for individual blood glucose values (r = 0.61) and for mean 24-hour blood glucose values (r = 0.73) repeated within 14 days showed an acceptable degree of reproducibility for the blood glucose profiles. Mean 24-hour blood glucose values fell significantly overall (11.4 to 9.8 mmol/l; 205 to 176 mg/100 ml) in 47 children who had repeated profiles more than 2 weeks apart. Unrecognised nocturnal hypoglycaemia (less than 3.0 mmol/l; 54 mg/100 ml) was found in 19% of children on twice-daily Semitard insulin. The study shows that children over age 7 years manage home blood glucose monitoring without difficulty. It shows that the results are reproducible and correlate with other indices of control, and that it provides a practical basis for the improvement of diabetic control.
A comparison of three methods for the estimation of capillary blood glucose in filter paper spots.
A comparison has been made between three methods for measuring capillary blood glucose collected on filter paper, including a new method using a Beckman glucose analyser 2. The methods are suitable for use with capillary blood spots collected onto filter paper for monitoring the control of diabetic patients. Their accuracy, precision, and recovery of glucose were similar. Glucose measurement with the Beckman glucose analyser 2 involves elution of the dried blood spots with 2% trichloroacetic acid and injection of a fraction of the eluate into the analyser. The method provides a simple and rapid alternative procedure for laboratories that do not have a heavy workload for this type of assay.
Cord blood C-peptide:glucose ratio - a good indicator of B cell function in infants of diabetic mothers.
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Brain gangliosides: an improved simple method for their extraction and identification.
Total ganglioside extracts prepared from brain tissue were concentrated either by dialysis against Carbowax or by employing Millipore filter cones. Thin-layer chromatography was then carried out using silica gel plates. After location of the various fractions quantitation was effected by direct densitometry. The methods that have been adopted are rapid and suitable for the study of brain gangliosides in post mortem and biopsy material in a clinical chemistry laboratory.
Keratan sulphate excretion in a patient with Kniest dysplasia.
The clinical and radiological features of a patient with Kniest dysplasia, a form of metatropic dwarfism, are described. The patient excreted glycosaminoglycans (mucopolysaccharides) in normal amounts during infancy but subsequently showed abnormal keratan sulphate excretion. The significance of these findings and the possibility that Kniest dysplasia represent another mucopolysaccharidosis are discussed.
Simple gas chromatographic screening procedure for lactic and pyruvic acids in human plasma.
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Abnormal keratan sulphate excretion.
Simple methods for the detection of keratan sulphate in urine have been applied to over 300 urine samples collected from children and adults with bone and cartilage dysplasias with or without mental retardation. Abnormal keratan sulphate excretion, which is a feature of type IV mucopolysaccharidosis (Morquio syndrome), is found in patients with that condition only during childhood. Abnormal excretion is also a feature of Kniest dysplasia and GM1 gangliosidosis and may be present in a number of other bone and cartilage dysplasias of unknown aetiology.
Identity of an oligosaccharide present in faeces in breast-fed neonates.
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Faecal excretion of oligosaccharides and other carbohydrates in normal neonates.
Chromatographic analysis of sugars in the stools of 40 normal newborn infants has shown the presence of an oligosaccharide in 85% of samples. The oligosaccharide has been shown to contain fucose (6-deoxygalactose), glucose, and galactose and is present in normal breast milk. In addition fucose has also been found in the presence of galactose in some samples and is probably a breakdown product of milk oligosaccharides. These findings, which affect the interpretation of faecal sugar excretion, have not been described previously.
Epiphyseal cartilage chemistry in thanatophoric dwarfism.
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The chemistry of human neonatal femoral epiphyseal cartilage.
The estimation of cartilage constituents such as hydroxyproline and hexosamine may be used to detect gross changes in the total amount of collagen and matrix. This simple approach, which can only be regarded as a "screening" procedure prior to more exhaustive analysis, has been applied to samples of neonatal human cartilage. It is suggested that this method would be useful in analysis cartilage biopsies, especially from patients with bone dysplasias.
Relation of urinary total hydroxyproline: Creatinine ratio to height velocity in children with retarded growth.
The urinary total hydroxyproline:creatinine ratio was measured on samples collected from 18 boys and 11 girls referred to a children's hospital because of small stature. Any serious degree of growth hormone deficiency was excluded and each child's growth and development was recorded over the following year. The hypothesis that the average hydroxyproline:creatinine ratio on random urine samples may be used to predict height velocity was examined. Such a prediction would have been incorrect on 35% of occasions, and it is concluded that this investigation cannot be used reliability to predict growth in height; it is probably only useful with sequential studies of an individual child over short periods while monitoring therapy.
Proceedings: Enzyme defects in mucopolysaccharidoses.
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A review and selection of simple laboratory methods used for the study of glycosaminoglycan excretion and the diagnosis of the mucopolysaccharidoses.
The current state of knowledge on the biochemical abnormalities in the mucopolysaccharidoses is reviewed. Methods for the estimation and identification of glycoasminoglycans excreted in the mucopolysaccharidoses are discussed and a selection of simple and reliable methods of value in a small hospital laboratory have been given in detail in an appendix.
The mucopolysaccharidoses.
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