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A Y Foo

Publications and source records attributed to A Y Foo.

At least 19 recordsLinked to original sources
PubMed1998

Amylase measurement with 2-chloro-4-nitrophenyl maltotrioside as substrate.

The use of 2-chloro-4-nitrophenyl maltotrioside (CNP-G3) as substrate to measure amylase (EC 3.2.1.1) activity in serum directly without the use of auxiliary enzymes was evaluated at two centres. The method was precise (within-run C.V. < 2% and between-run C.V. < 3%), there was no lag phase, background absorbance was low and there were minimal effects of pH changes. When compared with a method which uses 4,6-ethylidene (G7)-p-nitrophenyl (G1)-alpha-D-maltoheptaoside (EPS-G7) as substrate, the CNP-G3 method had greater sensitivity and longer reagent stability (21 days compared with 2 days at 4 degrees C). The activity measured with the CNP-G3 method correlated well with methods using either EPS-G7 and maltotetraose as substrates.

Amylases↗
PubMed1997

Familial hyperamylasaemia.

A six year old boy underwent extensive investigation for recurrent abdominal pain and was found to have a persistently raised serum amylase. Endoscopic retrograde cholangiopancreatography was normal and macroamylasaemia was excluded. Serum amylase concentrations were found to be raised in other family members spanning three generations, all of whom were asymptomatic. Clearance studies suggested no evidence of a renal tubular defect and serum lipase concentrations were normal. This is the first report of apparently familial hyperamylasaemia and the mode of inheritance is consistent with an autosomal dominant pattern.

Abdominal Pain↗
PubMed1993

Benign familial hyperphosphatasaemia as a cause of unexplained increase in plasma alkaline phosphatase activity.

AIMS: To consider a possible genetic origin for the persistent unexplained increase in plasma alkaline phosphatase (ALP) in five non-related patients referred over an 18 month period. METHODS: Plasma ALP isoenzyme activities were measured in patients and their first degree relatives. RESULTS: In each patient there was a noticeable increase in intestinal plasma ALP, either alone or accompanied by an increase in bone or liver ALP. Family studies showed an unexpected increase in plasma ALP and similar isoenzyme changes in first degree relatives. The findings were consistent with autosomal dominant inheritance. CONCLUSION: Inherited raised plasma ALP activity is a reasonably common cause of persistent unexplained hyperphosphatasaemia which deserves wider recognition.

Adult↗
PubMed1993

Renal isoamylase clearance as a measure of altered renal charge selectivity in patients with diabetes mellitus.

Microalbuminuria is well established as a marker for early renal damage in diabetic patients. Differences in charge selectivity in glomerular protein filtration may also be an early marker of renal damage. We investigated the possible usefulness of the renal clearances of pancreatic and salivary amylases, and the ratio of the two, as markers of early renal damage in 55 diabetic subjects and 21 healthy controls. Diabetic patients with established albuminuria and microalbuminuria had increased clearance of salivary amylase and a trend toward lower pancreatic/salivary amylase clearance ratios compared to healthy controls and diabetic subjects without albuminuria, but the overlap with controls and diabetics without albuminuria was too large for the test to be useful.

Adolescent↗
PubMed1993

Multicenter evaluation of Iso-ALP test kit for measurement of bone alkaline phosphatase activity in serum and plasma.

A test kit (Iso-ALP, Boehringer Mannheim) for measuring human bone alkaline phosphatase activity in serum or plasma was evaluated in five laboratories in three countries. The assay is based on the principle described by Rosalki and Foo (Clin Chem 1984;30:1182-6) and uses wheat germ lectin to precipitate bone alkaline phosphatase. Residual ALP in the supernate in comparison with total ALP is used to quantify the bone fraction. The imprecision of residual ALP measurement was low (median between-run CV 4.9%) and comparable with that of total ALP. Linearity of precipitation was demonstrable up to a bone ALP activity (diethanolamine buffer 37 degrees C) of 2000 U/L, though a matrix effect was observed for dilutions of high-activity sera in saline or bovine serum albumin. For assaying patients' samples, different batches of lectin demonstrated excellent comparability. Taking electrophoresis as a basis for standardization, we determined that the lectin precipitated approximately 90% of bone ALP, but < 5% of nonbone ALP. From this we derived serum/plasma upper reference limits for bone ALP activity in adults and children.

Adult↗
PubMed1991

Creatine kinase determination: a European evaluation of the creatine kinase determination in serum, plasma and whole blood with the Reflotron system.

We evaluated a new dry-reagent carrier system for the determination of creatine kinase (EC 2.7.3.2) activity, Reflotron CK, with special attention to analytical performance with whole blood. We found a good within series imprecision. The median coefficient of variation was 3.1% for Reflotron CK (blood, serum and plasma) and 0.9% for the automatic analysers (serum and plasma only). The between-days imprecision with Reflotron CK (median CV: less than or equal to 3%) was similar to that for the comparison method on different analysers. Fresh samples of human blood, plasma and serum were examined by Reflotron CK and by a N-acetylcysteine activated creatine kinase method in six different clinical laboratories and in the Evaluation Department of Boehringer Mannheim GmbH. The correlation between these methods was excellent (r greater than or equal to 0.99), the median systematic deviation (bias) for all samples being smaller than -5%. Haematocrits between 0.25 and 0.50, haemolysis up to 6 g/l haemoglobin, and icteric samples with bilirubin concentrations up to 0.2 g/l showed no interference. No drug in therapeutic concentration was found to affect the Reflotron CK results; ascorbic acid, calcium dobesilate and sulphamethoxazole lowered the values only when present in high concentrations. Reflotron CK may be considered as a suitable alternative for decentralized testing sites, especially in situations where creatine kinase results are needed quickly.

Autoanalysis↗
PubMed1987

Plasma intestinal alkaline phosphatase and intermediate molecular mass gamma glutamyltransferase activities in the differential diagnosis of jaundice.

An assessment was made of the value of: (i) the demonstration of intestinal alkaline phosphatase in plasma for the differentiation of intrahepatic from post-hepatic jaundice in 122 jaundiced patients; and (ii) the demonstration of an intermediate molecular mass gamma glutamyltransferase in plasma for the identification of post-hepatic cholestasis in 74 jaundiced patients. The first test had a diagnostic sensitivity of only 32% with a specificity of 86%; the second test had a sensitivity of 50% and specificity of 75%. It is concluded that neither procedure is worth while.

Alkaline Phosphatase↗
PubMed1987

Identification of bone and liver metastases from breast cancer by measurement of plasma alkaline phosphatase isoenzyme activity.

Plasma alkaline phosphatase isoenzyme activities were determined in patients with breast cancer to diagnose and monitor bone and liver metastases. Bone alkaline phosphatase activity was increased in 21 of 50 patients (42%) with radiologically confirmed bone metastases, while total alkaline phosphatase activity was increased in only 10 of 50 (20%); liver alkaline phosphatase activity was raised in 12 of 25 patients (48%) with liver metastases. All patients with liver metastases had bone metastases. Bone alkaline phosphatase activity was significantly higher in patients with symptomatic bone disease. Isoenzyme determination provided additional information that would have changed patient management in five of 20 patients who were monitored serially. Measurement of alkaline phosphatase isoenzyme activity, though less sensitive than imaging procedures, can assist in screening for, and in early detection of, a high proportion of bone and liver metastases, and can provide useful objective evidence of their response to treatment.

Adult↗
PubMed1987

Transient hyperphosphatasemia of infancy and early childhood: clinical and biochemical features of 21 cases and literature review.

Clinical and biochemical features of transient hyperphosphatasemia of infancy and early childhood are reviewed in 21 patients we have studied and in a further 93 cases reported in the literature. The diagnosis is suggested by the finding of an increased activity of alkaline phosphatase (EC 3.1.3.1) in plasma, typically more than fivefold the adult upper reference limit, in a child under five years of age, without evidence of liver or bone disease. The condition is confirmed by the presence of a characteristic pattern of alkaline phosphatase isoenzymes and by the normalization of the enzyme's activity in plasma within approximately three months. The etiology of the condition and possible mechanisms of the enzyme increase are discussed.

Age Factors↗