Intra-operative parathyroid hormone measurements - experience of a non-academic hospital.

BACKGROUND: Surgery is the treatment of choice for symptomatic primary hyperparathyroidism. The majority of research concerning intra-operative parathyroid hormone (ioPTH) measurements is conducted in university hospitals. Whether ioPTH measurements are feasible and useful in predicting the presence of remaining hyperfunctioning parathyroid tissue in a non-academic hospital remains uncertain. METHODS: Data were collected on all patients with biochemically proven and surgically treated primary hyperparathyroidism treated at the Reinier de Graaf Hospital from August 2002 to December 2007. RESULTS: Sixty-five patients were included. The mean pre-operative serum calcium level was 2.78 mmol/l (range 2.28 - 3.80 mmol/l, normal range 2.20 - 2.65 mmol/l) and the mean serum parathyroid hormone level 17.0 pmol/l (range 4.0 - 90.3 pmol/l, normal range 1.0 - 5.5 pmol/l). All patients were operated on for primary hyperparathyroidism, using ioPTH measurements during their first operation. Sensitivity and specificity rates of ioPTH measurements were 98% and 89%, respectively. The ioPTH test accurately indicated incomplete removal of all hyperfunctioning parathyroid tissue in 8 patients (12%). Five patients (8%) were re-explored immediately, of whom 4 were successfully treated in this single operative session. One patient was operated on successfully the next day. Two patients were operated on with a successful result during a second admission. In all the ioPTH measurements there was 1 false-positive result (1.5%) and 1 false-negative result (1.5%). The mean postoperative calcium value for the successfully treated patients was 2.34 mmol/l (range 2.14 - 2.71 mmol/l, normal range 2.20 - 2.65 mmol/l). The mean postoperative PTH level for the successfully treated patients was 3.76 pmol/l (range 0.40 - 7.1 pmol/l). CONCLUSION: Our data suggest that ioPTH measurements are feasible and useful in a non-academic hospital.

Initial activity and inactivation of alkaline phosphatase in different lots of buffer.

Alkaline phosphatase activities were determined in six lots of 2-amino-2-methyl-1-propanol (AMP) and in six lots of diethanolamine (DEA) buffers without preincubation of the sample. There appeared to be differences between the lot numbers in both cases, resulting in a variation in initial activity. When serum samples are preincubated with buffer a loss of activity was observed in 4 out of the 6 AMP buffers. Four human isoenzymes showed varying inactivation during preincubation with AMP buffer. No loss of activity was observed when the preincubation was done with the six DEA buffers. These results indicate that the purity of the commercially-available buffers is quite unsatisfactory.

Influence of zinc ions addition to different lots of 2-amino-2-methyl-1-propanol (AMP) buffer on the alkaline phosphatase activities.

The influence of Zn2+ on the inactivation of alkaline phosphatase [orthophosphoric monoester phosphohydrolase (alkaline optimum), EC 3.1 3.1] in serum during preincubation with 2-amino-2-methyl-1-propanol (AMP) buffers was investigated. Addition of Zn2+ to the buffer before preincubation increases the enzyme activity. An optimum Zn2+ concentration different for each lot of AMP buffer can be found, at which the enzyme activities are restored to a level equal to activities measured without preincubation. There is a relation between the inactivating properties of the different AMP buffers and the amount of Zn2+ needed to prevent this inactivation. Since Zn2+ chelating substituted diamines are held responsible for the inactivation by removing Zn2+ from the enzyme, we assume that the addition of Zn2+ to the buffer prevents this removal. As Zn2+ itself is an inhibitor of the enzyme, the addition of both too much or too little Zn2+ results in lower enzyme activities after preincubation with AMP buffer.

Alterations in carbohydrate composition of serum IgG from patients with rheumatoid arthritis and from pregnant women.

The carbohydrate composition of IgG purified from serum of patients with rheumatoid arthritis (RA), pregnant women, and blood donors has been determined by gas-liquid chromatography. Comparison of the results indicates that IgG from patients with RA contains significantly less galactose but more N-acetylglucosamine than normal IgG, whereas the fucose and sialic acid contents are not changed. The carbohydrate content of IgG in RA is reduced. IgG in pregnancy contains more galactose and more sialic acid than normal IgG, whereas fucose, N-acetylglucosamine, and the total carbohydrate content are not changed. These data suggest a temporal compensation of the RA associated undergalactosylation of IgG in female patients with RA during pregnancy, a period during which remission of the disease is often observed.

Absence of IgA nephropathy in patients with ankylosing spondylitis.

In 40 patients with ankylosing spondylitis (AS) no evidence for IgA nephropathy was obtained. This conclusion was based on the absence of hematuria and on the inability to find an increased incidence of IgA-containing immunoglobulin deposits in skin biopsies. Increased Clq binding assay was only found in those AS patients with anterior uveitis. In 26% of the skin biopsies perivascular mononuclear cell infiltrates were observed, and immunoglobulin deposits were seen in 65%. These facts suggest that the immunologic system is involved in the pathogenesis of this disease.

Lectin-enzyme immunoassay of transferrin sialovariants using immobilized antitransferrin and enzyme-labeled galactose-binding lectin from Ricinus communis.

A heterologous lectin-enzyme immunoassay is described. Microtiter plate wells were coated with affinity-purified antibodies to human transferrin. After incubation with transferrin sialovariants, prepared by limited neuraminidase treatment and separated with chromatofocusing, a lectin-enzyme-streptavidin complex was added. A good correlation was obtained between the number of terminal galactose groups on transferrin and the response in the lectin-enzyme immunoassay using Ricinus communis agglutinin as the galactose-binding lectin. The results indicate that characterization of glycosylation is possible with less than a microgram of the glycoprotein available, using lectin-enzyme immunoassays.