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Despite a stringent donor selection, human islet isolation remains frustratingly unpredictable. In this study, we measured acute insulin response to arginine (AIRarg), an in vivosurrogate measure of islet mass, in 29 human deceased donors before organ donation, and correlated values with the outcome of islet isolation. Thirteen isolations (45) met the threshold for clinical islet transplantation. Among all measured donor characteristics, the only discriminating variable between successful or unsuccessful isolations was donor AIRarg (p < 0.01). Using a threshold of 55 ?IUmL (ROC curve AUC: 72), isolation was successful in 1219 donors with high AIRarg and in 110 donors with low AIRarg (p < 0.001). The negative and positive predictive values were 90 and 63, respectively. If used to select donors in the entire cohort, AIRarg would have increased our success rate by 40 and avoided 56 of unsuccessful isolations while missing only 8 of successful preparations. Our results suggest that donor AIRarg is markedly superior to body mass index (BMI) and other criteria currently used to predict isolation outcome. If routinely performed in deceased donors, this simple test could significantly reduce the failure rate of human islet isolation.

Despite a stringent donor selection, human islet isolation remains frustratingly unpredictable. In this study, we measured acute insulin response to arginine (AIRarg), an in vivo surrogate measure of islet mass, in 29 human deceased donors before organ donation, and correlated values with the outcome of islet isolation. Thirteen isolations (45%) met the threshold for clinical islet transplantation. Among all measured donor characteristics, the only discriminating variable between successful or unsuccessful isolations was donor AIRarg (p < 0.01). Using a threshold of 55 μIU/mL (ROC curve AUC: 72%), isolation was successful in 12/19 donors with high AIRarg and in 1/10 donors with low AIRarg (p < 0.001). The negative and positive predictive values were 90 and 63%, respectively. If used to select donors in the entire cohort, AIRarg would have increased our success rate by 40% and avoided 56% of unsuccessful isolations while missing only 8% of successful preparations. Our results suggest that donor AIRarg is markedly superior to body mass index (BMI) and other criteria currently used to predict isolation outcome. If routinely performed in deceased donors, this simple test could significantly reduce the failure rate of human islet isolation.

We examined whether 1,25 dihydroxyvitamin D(3) (1,25 D(3)), the active form of vitamin D involved in the regulation of the immune system, may also protect human pancreatic islet cells from destruction induced by cytokines. In this study, we specifically investigated the effect of 1,25 D(3) on oxidative stress and major histocompatibility complex (MHC) induction, both implicated in cytokine-induced islet cell dysfunction and destruction. We also investigated the effects of 1,25 D(3) on interleukin (IL)-6, a pleiotropic cytokine implicated in the pathogenesis of immunoinflammatory disorders. Human pancreatic islets, isolated from heart-beating donors, were treated with a combination of three cytokines, IL-1beta+tumor necrosis factor alpha+interferon gamma, in the presence or absence of vitamin D, and compared with with untreated control cells. Metabolic activity was assessed by cell viability and insulin content. Oxidative stress was estimated by heat shock protein 70 (hsp70) expression, cell manganese superoxide dismutase (MnSOD) activity and nitrite release, a reflexion of nitric oxide (NO) synthesis. Variation of immunogenicity of islet preparations was determined by analysis of the MHC class I and class II transcripts. Inflammatory status was evaluated by IL-6 production. After 48 h of contact with cytokines, insulin content was significantly decreased by 40% but cell viability was not altered. MHC expression significantly increased six- to sevenfold as well as NO and IL-6 release (two- to threefold enhancement). MnSOD activity was not significantly induced and hsp70 expression was not affected by the combination of cytokines. The addition of 1,25 D(3) significantly reduced nitrite release, IL-6 production and MHC class I expression which then became not significantly different from controls. These results suggest that the effect of 1,25 D(3) in human pancreatic islets cells may be a reduction of the vulnerability of cells to cytotoxic T lymphocytes and a reduction of cytotoxic challenge. Hence, 1,25 D(3) might play a role in the prevention of type 1 diabetes and islet allograft rejection.

Summary The prognostic significance of estradiol (ER) and progesterone receptors (PgR) for survival from relapse has been studied in two groups of breast cancer patients: group 1, 35 patients in whom receptor levels were measured at the time of mastectomy; group II, 49 patients in whom receptor levels were measured at the time of recurrence. ER + (>10 fmoles/mg) patients had a better survival from relapse than ER — patients. High levels of PgR (>50 fmoles/mg) had a prognostic significance only in group II patients.

A continous line of human breast carcinoma cells, VHB-1, was established in culture following collagenase treatment of an infiltrating duct cell carcinoma. The cells displayed an epithelial pattern and multiplied rapidly. Maintained in monolayer culture, the VHB-1 cells exhibited a 30-h doubling time and a plating efficiency of 20%. The cells possessed an abnormal karyotype with a mode of 70–74 chromosomes per cell. the karyotype was heavily rearranged and numerous marker chromosomes were found. Transplantation of the cells into nude mice produced tumors bearing histological resemblance to the original material. The VHB-1 cells contained significant levels of prolactin receptors, were steroid hormone (estrogen, progesterone, androgen, glucocorticoid) receptor positive, and were capable of functional differentiation in vitro. These characteristics make the VHB-1 cell line a suitable model for studying the biological properties of human breast tumors.

Summary Total and free prolactin receptors were assayed in 72 human breast tumor biopsies. Forty-nine percent of the tumors are positive (specific binding greater than 0.8% of total radioactivity) when assaying free receptors, while 71% are positive when total receptors levels are determined. No clear relationship exists between the prolactin receptor positivity and the presence of either progesterone or estradiol receptors. Measurement of total prolactin receptors could be an important and independent criterion of the hormonal sensitivity of the tumors.

Breast tumor cells have been shown to be responsive to calcium in that external calcium modifies cell calcium, shape and growth. In order to highlight some of the numerous mechanisms by which calcium is operating, we investigated its influence on the cell microenvironment and particularly its effect on membrane-associated heparan sulfate proteoglycans. The breast cancer cells MCF-7 were grown either at low (0.04 mM) or high (2.5 mM) calcium concentration. After 3 days of culture, cells were labeled with Na235SO4 for 24 h and cell-associated proteoglycans extracted and purified. We showed that calcium enhances approximately twofold the synthesis of sulfated proteoglycans and, among these sulfated proteoglycans, chemical treatments indicated a specific two-to threefold increase of heparan sulfate proteoglycans. In view of the increasing implication of heparan sulfate proteoglycans in numerous mechanisms such as cell-cell contact, cell-matrix interactions and cell growth control, it appears that calcium may be a target for modulating metastatic and growth processes in breast tumor cells.

Summary Usingl-[3H]dihydroalprenolol ([3H]DHA), a potentß-adrenergic antagonist, we demonstrated in breast cancer cells the presence ofß-adrenergic receptors with high affinity (Kd 1–9 nM) as shown by Scatchard analyses. Natural and synthetic agonists inhibited the [3H] DHA binding in the following order of potency:l-isoproterenol=l epinephrine > > >l-norepinephrine, identical to the well-established order of potency for these compounds in producingß-adrenergic responses. We verified that these compounds actually stimulated cAMP production in breast cancer cells. At the present time, the pathophysiological significance ofß-adrenergic receptors remains unclear. In view of the importance of cAMP in lactose production and in tumor growth mechanisms, it seems to be important to characterize theß-adrenergic receptors in breast cancer cells in more detail and study their possible involvement in breast tumor growth.

Transferrin receptors were demonstrated on the cell membrane of breast cancer epithelial cells in primary or long-term culture. Diferric transferrin binding was saturable, specific and was not related to DNA content or clinical and histological features of the tumour. However a good correlation (p<0.01) was found between transferrin binding and thymidine incorporation. These results suggest the possibility of transferrin receptor measurement as a reflection of the proliferative activity of cultured breast tumour cells.