Evaluation of tartrate-resistant acid phosphatase (TRACP) 5b as bone resorption marker in irradiated bone metastases.

BACKGROUND: The aim of our study was to evaluate if the determination of the active isoform 5b of tartrate-resistant acid phosphatase (TRACP 5b) provides the possibility to monitor the effect of local radiotherapy in bone metastases and if TRACP 5b will predict further osseous progression. MATERIALS AND METHODS: In 48 breast cancer patients with bone metastases, patients' characteristics, diagnostic imaging and laboratory investigation, tumor- and therapy-related parameters were registered at the beginning and the end of radiotherapy, as well as 6 and 12 weeks afterwards. TRACP 5b activity was measured using a solid phase immunofixed enzyme activity assay with the monoclonal antibody O1A. RESULTS: During follow-up, progression in another part of the skeleton was diagnosed in 31 patients (65%). There was a significant decrease of TRACP 5b in patients without progression in non-irradiated regions, whereas in progressive disease, TRACP 5b levels remained stable with a slightly increasing tendency (p < 0.007). In patients with < or =3 metastases, all TRACP 5b values were significantly lower than the values of those with >3 metastases (p = 0.01). CONCLUSION: In patients without further osseous progression, TRACP 5b is able to monitor the effectiveness of local radiotherapy. The estimation of sensitivity and specificity based on each TRACP 5b value demonstrates that the ability to discriminate between those patients with or without osseous progression increases with time.

Tartrate-resistant acid phosphatase 5b as serum marker of bone metabolism in cancer patients.

BACKGROUND: The serum marker tartrate-resistant acid phosphatase isoform 5b (TRACP 5b) is considered a specific parameter of osteoclast activity and a useful marker of bone resorption. Regarding the utility of TRACP 5b in bone metastases, this review aims to draw clinically relevant conclusions. MATERIALS AND METHODS: The available literature data regarding the laboratory methods, the characteristics of TRACP 5b and the clinical data, as well as our own results about TRACP 5b in cancer patients has been reviewed. RESULTS: In contrast to enzymatic assays, two new assays based on a monoclonal antibody and on heparin-induced inhibition of TRACP 5a, respectively, demonstrated low biological and analytical variabilities in healthy subjects as well as in patients with osteoporosis. Up to now, only a few studies have evaluated the utility of TRACP 5b in cancer patients with bone metastases. In these studies, the sensitivity of TRACP 5b was higher compared to other markers. Furthermore, TRACP 5b activity correlates with the response to the treatment of bone metastases. CONCLUSION: Although the clinical data available are promising, the results are still preliminary. In addition to further evaluation of the analytical method, more studies in cancer patients are needed to establish TRACP 5b in the diagnostic procedure and in the therapy monitoring of bone metastases.

Behaviour of beta 2-adrenoceptors on lymphocytes under continuous and pulsatile tocolysis with Fenoterol.

The present study investigates the population of beta 2-receptors on lymphocytes in pregnant women with premature labor between the 29th and 34th week of pregnancy. The population of receptors on lymphocytes correlates with that on the myometrium, which is not accessible for study during pregnancy. Fourteen patients received a pulsatile tocolysis, while ten women received a continuous tocolysis with Fenoterol. Assuming an equal population of receptors in both groups before commencement of therapy, the numbers of receptors in the patients with continuous tocolysis fell to about 35% of the initial value after 72 hours. Under pulsatile tocolysis, the numbers of receptors remained unchanged for a period of three days and was still only just below 70% of the initial value by the seventh day. Our data demonstrate that continuous administration of the short-acting beta 2-agonist Fenoterol resulted in a substantial loss of beta 2-adrenoceptors on lymphocytes. In contrast, intermittent administration of the same beta 2-adrenergic agonist prevented the onset of receptor down-regulation in pregnant women with preterm labor. Further studies are required to investigate the impact of the decreased loss of beta 2-adrenoceptor density on the good clinical experience with intermittent tocolysis.