Intraoperative and postoperative PTH secretion mode in patients with hyperparathyroidism

The development of a sensitive 2-site immunoradiometric assay which detects only intact human PTH (1-84) enabled us to study kinetics of PTH secretion intraoperatively. In a prospective study, we assessed the PTH (1-84) secretion mode intraoperatively in 54 patients with adenomas, in 14 patients with tertiary hyperparathyroidism (HPT), and in 2 patients with persistent HPT. After the removal of adenomatous or hyperplastic tissue, a significant drop of PTH (1-84) concentration was seen. A 50% decrease in the basal PTH concentration was reached significantly earlier for adenomas than for hyperplasias. In the 2 cases with unrevealing neck exploration, the PTH (1-84) concentrations showed hardly any change. The recovery of PTH secretion was studied in 23 patients, 20 of whom had a single adenoma; in 2 cases, a hyperplasia was present and 1 patient showed the clinical signs of a toxic HPT. We found an initial drop of PTH concentration 4 hours postoperatively below the limit of detection and a rapid recovery within 24 hours postoperatively. The PTH concentration values were well within the normal range after 48-72 hours.

Intact parathyroid hormone in primary hyperparathyroidism

In 49 patients with primary hyperparathyroidism, intact parathyroid hormone (PTH) was measured with a recently developed immunoradiometric assay, and midregional PTH fragments (sequence 44-68) were measured with an established radioimmunoassay technique. In 47 normal subjects, the concentration of intact PTH ranged from 2.0 to 6.8 pmol/l, and in 49 patients with primary hyperparathyroidism it ranged from 6.4 to 80.0 pmol/l. In contrast, midregional PTH fragments were normal in seven of 49 patients with primary hyperparathyroidism. In five healthy controls and in 12 patients with surgically confirmed primary hyperparathyroidism and serum calcium levels below 3.0 mmol/l, a rapid calcium loading test was performed. In healthy controls, intact PTH was in the low normal to subnormal range within 2.5-5.0 min, and had recovered within 15 min of calcium infusion. In patients with primary hyperparathyroidism, the calcium infusion also led to a 30-50 per cent decrease in intact PTH levels within 5.0-7.5 min after injection, with a slow recovery after 10-15 min. In six of the patients with only slightly elevated basal intact PTH, a suppression to the normal range was observed. In 24 patients (16 patients with a solitary adenoma and eight patients with four-gland hyperplasia) the intact PTH levels were followed intraoperatively during parathyroidectomy, revealing a significantly different rate of decline for single adenomas compared with hyperplasia during the first 15 min after removal of the primary enlarged gland. Intact PTH values remained constantly elevated in one patient with primary hyperparathyroidism and an unsuccessful neck exploration. These results confirm that (a) the measurement of intact PTH in patients with primary hyperparathyroidism is superior to the measurement of midregional fragments; (b) PTH secretion in primary hyperparathyroidism is not totally autonomous; and (c) intraoperative monitoring of intact PTH values could be used to monitor the success of surgery.

Two-site immunochemiluminometric assay of intact human parathyrin in serum with use of a tracer peptide purified by reversed-phase high-performance liquid chromatography

For this two-site immunochemiluminometric assay of intact human parathyrin (hPTH), the luminescent tracer was synthetic hPTH(53-84), conjugated via succinimide linkage to (aminobutyl)ethyl-isoluminol hemisuccinimide (abei-h). Purification of the labeled hPTH(53-84) by reversed-phase high-performance liquid chromatography allowed isolation of the conjugate having the highest incorporation of abei-h, 1.6 mol per mole of hPTH(53-84). The solid-phase antibody directed against the N-terminal part of hPTH was immobilized by adsorption onto the polystyrene surface of the assay tube and extracted the intact hPTH and N-terminal fragments. Another antibody against synthetic hPTH(53-84), which bound to the C-terminal part of intact hPTH, was indirectly labeled at its second free binding site with the abei-h-labeled hPTH(53-84). The assay has a detection limit of 0.5 pmol/L; it is accurate, precise, and reliable; and it shows a linear response for samples containing up to 100 pmol of hPTH per liter. The normal reference interval ranged from 1.8 to 5.9 pmol/L; 56 patients with primary hyperparathyroidism had concentrations ranging from 5.9 to 113 pmol/L. The concentrations detected in patients with idiopathic hypoparathyroidism were below the normal reference interval.

Two-site immunochemiluminometric assay of intact human parathyrin in serum with use of a tracer peptide purified by reversed-phase high-performance liquid chromatography

For this two-site immunochemiluminometric assay of intact human parathyrin (hPTH), the luminescent tracer was synthetic hPTH(53-84), conjugated via succinimide linkage to (aminobutyl)ethyl-isoluminol hemisuccinimide (abei-h). Purification of the labeled hPTH(53-84) by reversed-phase high-performance liquid chromatography allowed isolation of the conjugate having the highest incorporation of abei-h, 1.6 mol per mole of hPTH(53-84). The solid-phase antibody directed against the N-terminal part of hPTH was immobilized by adsorption onto the polystyrene surface of the assay tube and extracted the intact hPTH and N-terminal fragments. Another antibody against synthetic hPTH(53-84), which bound to the C-terminal part of intact hPTH, was indirectly labeled at its second free binding site with the abei-h-labeled hPTH(53-84). The assay has a detection limit of 0.5 pmol/L; it is accurate, precise, and reliable; and it shows a linear response for samples containing up to 100 pmol of hPTH per liter. The normal reference interval ranged from 1.8 to 5.9 pmol/L; 56 patients with primary hyperparathyroidism had concentrations ranging from 5.9 to 113 pmol/L. The concentrations detected in patients with idiopathic hypoparathyroidism were below the normal reference interval.

Two-site assay of intact parathyroid hormone in the investigation of primary hyperparathyroidism and other disorders of calcium metabolism compared with a midregion assay

We compared the utility of measurements of serum intact human PTH-(1-84) and midregion human PTH-(44-68) in patients with disorders of extracellular calcium metabolism. Serum midregion PTH was determined by RIA, and serum intact PTH was measured by a sensitive and specific immunoradiometric two-site assay. The serum intact PTH concentrations in 70 patients with primary hyperparathyroidism were above the normal range in 69, and thus widely separated from the levels in 40 patients with hypercalcemia of malignancy, in whom serum intact PTH values were usually below normal. In contrast, both groups had overlapping serum midregion PTH values. In patients after renal transplantation and those with chronic renal failure, serum intact PTH levels were in the normal range twice as often as were serum midregion PTH values. The intact PTH assay was also superior in detecting venous gradients of the hormone and changes in PTH secretion caused by altered serum calcium concentrations, and serum intact PTH was remarkably low in hepatic venous effluent. We conclude that this new assay for serum intact PTH is superior to the midregion RIA in investigating parathyroid function in several different clinical conditions.

[Lichen sclerosis et atrophicus as a cause of acquired phimosis--circumcision as a preventive procedure against penis cancer?]

From January to December 1985, circumcision for acquired phimosis was performed at our department in 140 boys with a median age of 4 3/4 years. The histological examination of the prepuce revealed the existence of lichen sclerosus et atrophicus (LSA) in 6 cases, e.g. 4.3% of all circumcisions performed. The striking frequency of this chronic inflammatory epithelial change and the often cited connection between the existence of LSA and the development of penile cancer during adulthood as well as the well-known tendency towards the incidence of recurrent phimosis in LSA patients support the claim for total circumcision in these cases.

Does in vitro colony formation and chemosensitivity relate to DNA ploidy and S-phase fractions?

In vitro colony formation and chemosensitivity were analyzed in 65 human solid tumors and compared to proliferation parameters simultaneously obtained by DNA flow cytometry of the same tumor specimens. Colony growth in the human tumor colony assay was enhanced in aneuploid tumors (39/65) in comparison to diploid tumors (26/65, P less than 0.05). In addition, there was a relationship between % S-phase and colony growth. The existence of polyploid sublines (23/65) improved in vitro growth even in tumors with a diploid main G0/1-peak or with a low % S-phase. Metastases exhibited a higher proportion of aneuploidy and showed slightly better growth in vitro than primary tumors. Sensitivity testing in 34 of the 65 tumors showed no convincing relation between DNA parameters and the inhibition of colony formation by five standard anticancer agents with different mechanisms of action. This indicates additional factors other than the proliferative activity of the tumor to be responsible for drug sensitivity or resistance.

Comparison of 5-FU versus FUDR activity in human colorectal cancer using an in vitro clonogenic assay (HTCA)

Comparative in vitro drug testing was performed in 72 of 183 surgically removed human colorectal cancer specimens (34 primary lesions, 38 metastases). In 10 of these tumors, comparative dose-response curves were obtained. Given a greater than or equal to 70% ICF (inhibition of colony formation) as threshold for in vitro sensitivity, 5-FU was active in 16/62 specimens, and FUDR in 14/62. Significantly discordant sensitivity results were observed in 8/62 tests, 5-FU being the more active agent in 5 of these cases. These data are supported by the finding of 3 considerably differing dose-response curves in 10 additional comparative studies of human primary tumors.

Is chemosensitivity testing for peri-operative treatment planning in gastro-intestinal cancer by the human tumour colony assay worthwhile?

Based on the concept of a combined modality cancer treatment in surgical oncology, the use of the human tumour colony assay for routine chemosensitivity testing and prospective treatment planning was investigated in 204 surgical biopsies of primary human solid tumours. The majority of the tumours (135/204) were of gastro-intestinal (GI) origin. Sufficient growth for drug testing occurred in 29-67% of all tumours depending on the tumour type, with a mean of 36% in GI-carcinomas. Chemosensitivity testing in vitro against standard anti-cancer agents correlated well with clinical experience, 5-FU and FUDR being the most active drugs (27% respectively 24% sensitive tumours in vitro) in GI-carcinomas. Relatively good agreement of in vitro/in vivo correlations was seen with an overall of 25/32 correct predictions in GI and other tumours. Predictivity was particularly good for loco-regional chemotherapy. Nevertheless, the limited in vitro growth rate of gastro-intestinal tumour specimens and their chemoresistance restrict the use of this method-in particular with respect to individual treatment planning.

Potentiation by amphotericin B of the cytotoxicity of anticancer agents against MOPC-315 plasmacytoma and Lewis lung carcinoma

The ability of amphotericin B (AmB) to potentiate the cytotoxicity of several different anticancer agents against two murine tumor models was examined. A spleen colony assay was used to quantitate the cytotoxicity of BCNU, CCNU, and L-PAM, either alone or in combination with AmB against the MOPC-315 plasmacytoma. A high level of potentiation of the effects of CCNU and L-PAM by AmB occurred, but AmB did not increase the cytotoxicity of BCNU. Tumor growth curves and calculation of cell survival demonstrated significant potentiation of the cytotoxicity of CCNU by AmB against SC Lewis lung carcinoma.

Differential effect of hyperthermia on murine bone marrow normal colony-forming units and AKR and L1210 leukemia stem cells

Thermal dose-survival curves for normal hematopoietic and leukemia cells were assessed by spleen colony assays after in vitro heat exposure ranging from 41 degrees to 45 degrees. No effect of 43 degrees heat treatment on the fraction of cells lodging in the spleen was observed. Marked differences in heat sensitivity were observed between normal, L1210, and AKR leukemia cells, the first being les sensitive than were the malignant cells. Furthermore, a greater relative difference between normal stem cells and leukemia cells was observed at lower temperatures. Normal bone marrow cells forced into regenerative activity prior to heat treatment were more heat sensitive than was their undisturbed counterpart, suggesting that noncycling hematopoietic cells are less heat sensitive than are proliferating cells.

Chemosensitivity testing of human neoplasms using the soft agar colony assay

An in vitro soft agar assay for cloning of primary human tumour cells and sensitivity testing to anticancer agents has been developed by Hamburger and Salmon (human tumour stem cell assay, HTSCA). Based on the stem cell model, this assay may predict chemosensitivity for a defined tumour cell subpopulation of human solid neoplasms. But, methodological problems like the representative quality of a tumour sample, the disaggregation as well as the limited plating efficiency have to be solved before the clinical value of this test can be evaluated. Depending on the histological tumour type a sufficient colony growth for chemosensitivity testing can only be obtained in about 1/3 of all cases. Because of the limited biopsy material, more than five anticancer agents can only be tested in half of all assays. Paradoxical dose-response relationships for cytostatic agents or radiation in vitro point to artifacts. In vivo pharmacokinetics can only be partly imitated by in vitro conditions. Quality-control trials using an established cell line reveal a variability of the in vitro test conditions for certain agents. In addition, the testing of different tumour biopsy samples of the same patient yields variable results. In spite of the methodological problems, large in vivo-in vitro trials show sufficient correlations. The results reflect the high proportion of resistance of human solid tumours. Further development and improvement of the assay promises application of the test system in preclinical testing of anticancer agents.

Analysis of MOPC-315 plasmacytoma by elutriation and flow cytometry

Intravenously transplanted murine plasmacytoma MOPC-315 cells were separated from normal spleen cells from a tumour-bearing mouse by elutriation and characterized according to morphology, immunologic properties and clonogenicity. Morphologically, both lymphocytoid and plasmacytoid cells were separable by elutriation. Flow cytometry correlated DNA content and intracytoplasmic IgA content and demonstrated two distinct populations, both in cell cycle, but with markedly different cellular IgA levels. Density gradient separation characterized the lower-density cells with lower IgA content and higher clonogenicity. From these studies a model of cellular differentiation is proposed.

The effect of hyperthermia on hemopoietic progenitor cells of the mouse

We have studied the effect of heat on four lineage-specific clonogenic cells from mouse bone marrow. The thermal sensitivities of two red cell precursors, one primitive (BFU-E) and one more differentiated (CFU-E), a granulocyte-macrophage precursor (CFU-GM), and a megakaryocyte precursor (CFU-M) were determined after exposure to 42, 43, and 44 degrees C. We found that the erythroid precursors were much more heat sensitive than either the CFU-GM or CFU-M. At 42 degrees C the CFU-E and BFU-E had a D0 of about 30 min, while the CFU-GM and CFU-M had D0 values of about 60 min. Thus the four progenitors could be divided into two distinct classes with respect to their sensitivity to hyperthermia. These results suggest that erythropoiesis is more likely to be suppressed than either thrombopoiesis or leukocyte production when hyperthermia is applied in a clinical setting.