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Biomedical subjects

A Y Foo

Publications and source records attributed to A Y Foo.

36 records · Page 2Linked to original sources
PubMed1985

Incubation with neuraminidase and affinity electrophoresis with wheat-germ lectin compared for separating and quantifying alkaline phosphatase isoenzymes in plasma.

Of 98 patients' specimens examined for alkaline phosphatase (EC 3.1.3.1) isoenzymes by electrophoresis on cellulose acetate membrane after incubation with neuraminidase, 50 showed only a single liver or bone isoenzyme staining band; in 15 of these, the tissue origin of the fraction could not be accurately identified from its electrophoretic location. In the remaining 48 specimens, both liver and bone fractions were identifiable, but in only 25 of these was the electrophoretic resolution sufficient to yield separate peaks on densitometry. In contrast, both liver and bone alkaline phosphatase isoenzymes were identified in 95 of the 98 specimens by affinity electrophoresis involving wheat-germ lectin, the detection of both fractions being in agreement with the results of sequential heat inactivation. The tissue origin of the enzyme bands was readily ascertainable from their consistent electrophoretic location in this medium, and in 89 of the specimens the isoenzyme fractions could be resolved into separate peaks on densitometry. We conclude that resolution of liver and bone alkaline phosphatase by incubation with neuraminidase followed by cellulose acetate electrophoresis is greatly inferior to that obtained by wheat-germ lectin affinity electrophoresis.

Alkaline Phosphatase↗
PubMed1984

Measurement of biliary alkaline phosphatase by mini-column chromatography and by electrophoresis and its application to the detection of liver metastases in patients with breast cancer.

We describe a simple, rapid, and reproducible ion exchange mini-column chromatographic method for the quantitative measurement of biliary alkaline phosphatase in plasma. We have used this method to evaluate a cellulose acetate electrophoretic method, which was used to assess the value of measuring biliary alkaline phosphatase in 85 patients with breast cancer investigated for possible hepatic metastases. Biliary alkaline phosphatase activity was abnormal in 19 of 24 patients (79%) with liver metastases, but abnormalities were also found in 12 of 61 patients (20%) without hepatic metastases; in only 37% of patients with positive test results was this a consequence of liver metastases. For the identification of liver metastases, therefore, the method has useful sensitivity but limited specificity. Neither sensitivity nor specificity was significantly better than that of plasma gamma-glutamyltransferase activity, which was measured concomitantly.

Alkaline Phosphatase↗
PubMed1984

A new alkaline phosphatase isoenzyme abnormality.

We report on a new alkaline phosphatase isoenzyme abnormality occurring as an incidental finding in a male infant aged 4 months. Isoenzyme electrophoresis on cellulose acetate showed a prominent, diffuse alkaline phosphatase staining band in the alpha 1-globulin position together with a second band in the alpha 2/beta region and minor 'trailing' in the intermediate alpha 2 region. Normal liver and bone alkaline phosphatase were absent and intestinal phosphatase was not detected. On acrylamide gel electrophoresis a marked origin band was detectable suggesting the presence of high molecular weight enzyme. In addition, a series of compact bands in the alpha 2/beta position was present cathodal to the usual liver and bone isoenzymes. Total alkaline phosphatase activity was marginally elevated and was heat labile, L-phenylalanine resistant and partially L-homoarginine and L-leucine sensitive.

Alkaline Phosphatase↗
PubMed1984

Two new methods for separating and quantifying bone and liver alkaline phosphatase isoenzymes in plasma.

We describe two new methods for the separation and quantification of the bone and liver isoenzymes of alkaline phosphatase (EC 3.1.3.1) in plasma. In the first, we use wheat-germ lectin to precipitate the bone isoenzyme. About 80% of this, but minimal liver isoenzyme, is precipitated. The activity of the bone isoenzyme is calculated from measuring the alkaline phosphatase activity in the precipitate, that of liver alkaline phosphatase by subtracting the activity of the bone isoenzyme from total alkaline phosphatase activity. The liver fraction will also contain biliary, intestinal, and placental alkaline phosphatase if these are present in the original plasma, but correction for such activity is readily made. In the second method, samples are separated on cellulose acetate membranes that, before electrophoresis, have been soaked in buffer containing wheat-germ lectin. The bone isoenzyme is retarded and clearly separated from the liver fraction, allowing these isoenzymes to be quantified by densitometry. Both methods are rapid, reproducible, and suitable for use in the diagnostic laboratory.

Adult↗
PubMed1982

The pancreas in primary biliary cirrhosis and primary sclerosing cholangitis.

In patients with primary biliary cirrhosis, the chronic cholestasis, salivary, and lacrimal hyposecretion suggest that the disease is a "dry gland" syndrome. To determine whether or not pancreatic damage occurs in primary biliary cirrhosis and other forms of chronic cholestasis, we have studied pancreatic structure and function in primary biliary cirrhosis, and primary sclerosing cholangitis. In a retrospective study, retrograde pancreatograms were abnormal in 43% of 35 patients with primary biliary cirrhosis and 15% of 20 patients with primary sclerosing cholangitis (p less than 0.02). In a prospective study, serum pancreatic isoamylase was abnormal in 56% of 41 patients with primary biliary cirrhosis and 36% of 22 patients with primary sclerosing cholangitis (NS), indicating pancreatic damage in both diseases. After secretin-pancreozymin stimulation, patients with primary biliary cirrhosis, but not patients with primary sclerosing cholangitis, showed a significant reduction in duodenal juice flow rate (p less than 0.01) and immunoreactive trypsin output (p less than 0.01). The reduced trypsin output in patients with primary biliary cirrhosis indicates pancreatic hyposecretion. In neither patients with primary biliary cirrhosis nor patients with primary sclerosing cholangitis was the immunoreactive trypsin concentration, or tryptic activity in duodenal juice, significantly different from controls. Pancreatic involvement in primary biliary cirrhosis is closely associated with Sjogrens syndrome, and it is likely that the pancreatic hyposecretion is a component of the sicca complex. This association was not obvious in primary sclerosing cholangitis.

Cholangitis↗
PubMed1981

A new fluorescence method for gamma-glutamyltransferase isoenzyme demonstration.

A new fluorescence method for demonstrating gamma-glutamyltransferase isoenzymes using gamma-glutamyl-5-amino-4-methyl coumarin, a commercially available, non-carcinogenic substrate is described. The procedure can readily detect gamma-glutamyltransferase isoenzymes in samples with total activity as low as 5 U/l at 30 degrees C.

Fluorescence↗
PubMed1981

Comparison of procedures for the measurement of the anodal isoenzymes of lactate dehydrogenase in serum.

Lactate dehydrogenase (LD) isoenzyme-1 levels (LD1) determined after immunoprecipitation of M-subunits, LD1 activity by electrophoresis, and the activities of alpha-hydroxybutyrate dehydrogenase (HBD), urea-stable LD, and heat-stable LD, by Association of Clinical Biochemists Proposed Methods, were examined for their ability to differentiate between serum samples from patients with cardiac or liver disease. Compared with total LD, all methods gave higher serum activity in patients with cardiac disease than in those with liver disease. Differentiation between patient groups was greatest for LD1 by immunoprecipitation, followed by heat-stable LD and LD1 by electrophoresis. HBD and urea-stable LD both gave less discrimination, with negligible difference between these two procedures. LD1 activity by immunoprecipitation correlated well with LD1 activity determined by isoenzyme electrophoresis with densitometric scanning. The advantages and disadvantages of the various procedures are considered.

Drug Stability↗
PubMed1980

Serum 25-hydroxyvitamin D levels and vitamin D intake in healthy young adults in Britain and Denmark.

The serum 25-hyroxyvitamin D (25-OHD) concentrations of healthy young hospital laboratory workers in Britain and Denmark were compared in relation to assay variation and vitamin D intake. Serum samples from subjects in London and Copenhagen were assayed in both countries. The Danish assay gave higher values than the British assay with a correlation r = 0.88 and a linear regression of British values on Danish values of y = 0.60x + 3.35. Factors which might account for this difference were differences in the extraction procedure and in the range of values covered by the standards used in the two countries. However, the mean serum 25-OHD concentrations of the Danish group were significantly higher than those of the British group when all the samples were assayed in both countries. The mean total daily vitamin D uptake of the Danish group was significantly higher than that of the British group but this difference was almost entirely due to the regular intake of vitamin D tablets by sixteen of the twenty-five Danish subjects. Only one British subject took supplements. The vitamin D content of the food eaten was similar in the two groups. No correlation was found between dietary, as opposed to supplementary, vitamin D intake and serum 25-OHD levels presumably because the exposure of these subjects to ultra-violet light was adequate to compensate for minor differences in intake.

Adult↗
PubMed1979

Lecithin-cholesterol acyltransferase and the lipoprotein abnormalities of parenchymal liver disease.

1. Detailed studies have been made of the plasma lipoprotein abnormalities in parenchymal liver disease to test the hypothesis that the abnormalities would correlate with plasma lecithin-cholesterol acyltransferase (LCAT) activity. 2. When LCAT was high, very-low-density-lipoproteins (VLDL) were normal in composition and had a normal pre-beta electrophoretic mobility. When LCAT was low, VLDL concentrations were greatly reduced. 3. With high LCAT low-density lipoproteins (LDL) were normal. The LDL particles found with low LCAT activity were of normal size but of abnormal composition, being triglyceride rich and cholesteryl ester poor. Regardless of LCAT activity LDL were present in normal amounts. 4. High-density lipoproteins (HDL) were normal in composition and electron-microscopic appearance when LCAT activity was high. When LCAT activity was low HDL were abnormal in composition and 'stacked discs' were seen on electron microscopy. 5. These results suggest that low LCAT activity may be the cause of at least some of the lipoprotein changes of parenchymal liver disease.

Adult↗
PubMed1977

Metabolic response to intravenous salbutamol therapy in acute asthma.

In patients suffering from an acute attack of asthma the effects of salbutamol infusion (10 microng/min) on their plasma concentrations of non-esterified fatty acids (NEFA), triglyceride, insulin, and glucose were compared with those in a group of asthmatics not requiring infusion. Salbutamol was found significantly to increase the plasma concentrations of glucose and insulin while having little effect on NEFA or triglyceride. However, NEFA concentrations were found to be significantly increased in patients with an acute attack of asthma at the time of their admission to hospital. This increase is attributed to the stress of the asthmatic attack itself.

Acute Disease↗
PubMed1976

Hydroxyapatite - a reagent for the separation of free and antibody-bound steroid during the radioimmunoassay.

The use of hydroxyapatite to absorb antibody-bound steroid and thus separate free and antibody-bound steroid during radioimmunoassay has been examined using three steroid antisera (to testosterone, to 17-hydroxyprogesterone and to estradiol-17beta). For all three antisera studied the separation was shown to be independent of length of time in contact with hydroxyapatite (up to 1h); temperature variations from 4 degrees -37 degrees and pH over the range 4.9-8.0. The presence of protein affected the absorption of antibody-bound steroid but this effect could be overcome by the addition of increasing amounts of hydroxyapatite. Further increase in the amount of hydroxyapatite added had no effect on the separation of free and bound steroid. Sodium phosphate buffers of molarity greater than 0.01M eluted antibody-bount steroid from hydroxyapatite, but Tris-HC1 buffers up to molarities of 0.1 M had no effect. Hydroxyapatite when used as a dry powder had the same effects as suspensions. No effect on the cross-reactivities of the antisera used could be demonstrated when hydroxyapatite was used and plasma testosterone assays on 22 plasma samples using hydroxyapatite gave essentially the same results as assays on the plasma using a coated-tube assay. Hydroxyapatite can also be successfully pumped along small bore plastic tubing without settling and can thus be used in automated immunoassay systems.

Estradiol↗
PubMedDate not supplied

Lectin affinity electrophoresis of alkaline phosphatase for the differentiation of bone and hepatobiliary disease.

An affinity electrophoresis procedure is described for the separation and quantification of the bone- and liver-derived fractions of alkaline phosphatase in plasma. Separation is carried out on cellulose acetate membrane pre-soaked with buffer containing wheat germ lectin. The electrophoretic mobility of the bone enzyme is preferentially retarded by the lectin and this fraction is well separated from the liver fraction. After separation, enzyme activity is demonstrated by staining using an indigogenic alkaline phosphatase substrate incorporated in agar gel, and the stained fractions quantified by densitometry. The procedure has low imprecision, good linearity, and the activities of the bone and liver fractions correlate well with values obtained using nonelectrophoretic quantification methods. The procedure is especially suitable for use in the diagnostic laboratory.

Alkaline Phosphatase↗