There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Osteoclasts are specialized cells derived from the monocyte/macrophage haematopoietic lineage that develop and adhere to bone matrix, then secrete acid and lytic enzymes that degrade it in a specialized, extracellular compartment. Discovery of the RANK signalling pathway in the osteoclast has provided insight into the mechanisms of osteoclastogenesis and activation of bone resorption, and how hormonal signals impact bone structure and mass. Further study of this pathway is providing the molecular basis for developing therapeutics to treat osteoporosis and other diseases of bone loss.

Osteoclast differentiation and activation

Background Sipuleucel-T, an autologous active cellular immunotherapy, has shown evidence of efficacy in reducing the risk of death among men with metastatic castration-resistant prostate cancer. Methods In this double-blind, placebo-controlled, multicenter phase 3 trial, we randomly assigned 512 patients in a 2:1 ratio to receive either sipuleucel-T (341 patients) or placebo (171 patients) administered intravenously every 2 weeks, for a total of three infusions. The primary end point was overall survival, analyzed by means of a stratified Cox regression model adjusted for baseline levels of serum prostate-specific antigen (PSA) and lactate dehydrogenase. Results In the sipuleucel-T group, there was a relative reduction of 22% in the risk of death as compared with the placebo group (hazard ratio, 0.78; 95% confidence interval [CI], 0.61 to 0.98; P = 0.03). This reduction represented a 4.1-month improvement in median survival (25.8 months in the sipuleucel-T group vs. 21.7 months in the placebo group). The 36-month survival probability was 31.7% in the sipuleucel-T group versus 23.0% in the placebo group. The treatment effect was also observed with the use of an unadjusted Cox model and a log-rank test (hazard ratio, 0.77; 95% CI, 0.61 to 0.97; P = 0.02) and after adjustment for use of docetaxel after the study therapy (hazard ratio, 0.78; 95% CI, 0.62 to 0.98; P = 0.03). The time to objective disease progression was similar in the two study groups. Immune responses to the immunizing antigen were observed in patients who received sipuleucel-T. Adverse events that were more frequently reported in the sipuleucel-T group than in the placebo group included chills, fever, and headache. Conclusions The use of sipuleucel-T prolonged overall survival among men with metastatic castration-resistant prostate cancer. No effect on the time to disease progression was observed. (Funded by Dendreon; ClinicalTrials.gov number, NCT00065442.)

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Sipuleucel-T immunotherapy for castration-resistant prostate cancer.

admission. This proportion could already be greater in some parts of the country and may increase if referrals of cases of self-poisoning increase faster than the facilities for their assessment and management. The provision of social work and psychiatric expertise in casualty departments may be one means of preventing unnecessary medical admissions without risk to the patients. Dr Blake's and Dr Bramble's figures do not demonstrate, however, that any advantage would attach to medical teams taking over assessment from psychiatrists except that, by implication, assessments would be completed sooner by staff working on the ward full time. What the figures actually suggest is that if assessment of overdoses were left to house doctors there would be an increase in admissions to psychiatric units (by 19°U), outpatients (by 5O°'), and referrals to social services (by 140o). So for house doctors to assess overdoses would provide no economy for the psychiatric or social services. The study does not tell us what the consequences would have been for the six patients who the psychiatrists would have admitted but to whom the house doctors would have offered outpatient appointments. E J SALTER

Vitamin D deficiency.

Both bisphosphonates and radiotherapy are highly effective for the management of bone metastases. Our in vitro study examined the cytotoxic effects resulting from combinations of ibandronate and ionising radiations (RX) in various sequences on breast cancer cells. Single radiation doses were given before, at halftime of, or after acute ibandronate incubation (48 h). Single or fractionated radiation doses were applied at the end of chronic ibandronate incubation (5 weeks). Combination of acute ibandronate exposure and single radiation doses led to synergistic cytotoxic effects in MDA-MB-231 cell line, but only with low ibandronate concentrations in MCF-7 cell line. In both cell lines, synergy was more marked when ibandronate followed RX. After long-term ibandronate exposure, only high single radiation doses induced synergistic effects in MDA-MB-231 cell line. Synergy was only detected with low ibandronate concentrations in MCF-7 cell line. In both cell lines, fractionated radiation doses exerted similar effects. The combination of ibandronate with radiation can exert synergistic effects on the inhibition of breast cancer cells growth, depending on cell line, drug sequence and dosage. Our data might provide a rationale for associating bisphosphonates and radiotherapy for the treatment of bone metastases from breast cancer.

Sequence- and concentration-dependent effects of acute and long-term exposure to the bisphosphonate ibandronate in combination with single and multiple fractions of ionising radiation doses in human breast cancer cell lines

We have reported the existence of specific and high-affinity calcitonin (CT) receptors on normal human T-lymphocytes Because of the increasingly recognized importance of interleukin-1 (IL-1) and IL-6 in the control of bone metabolism, we have examined their influence on the binding parameters of labeled salmon calcitonin (sCT) on lymphocytes After a 24-hour incubation, IL-1 at 100–5000 U/ml and IL-6, at 1–1000 U/ml, decreased the apparent number of CT binding sites (Bmax) on T-lymphocytes The effects of IL-6 on purified T-lymphocytes were dose related and 100 U of IL-6/ml reduced sCT binding to 57±16% (mean ± SD) of the control values (n=6) There was no significant change in CT binding affinity (Kd, 071±054x10-10 M for controls versus 090±055x10-10 M after IL-6) and the decrease in Bmax was reversible after 48 hours The effects of IL-1 appeared to be mediated through an increased production of IL-6 as they were neutralized by a polyclonal antiserum against IL-6 Added alone, the antiserum caused a slight increase in the apparent number of CT binding sites on T-lymphocytes to 115±5% of control values (n=3) In summary, IL-1 and IL-6 can induce a marked apparent loss of CT binding sites on normal T-lymphocytes at concentrations known to be active on bone metabolism The contributions of our observations to the osteolytic activity of these cytokines deserve further investigation

Regulation of lymphocyte calcitonin receptors by interleukin-1 and interleukin-6.

The objective of this study was to determine the calcitonin (CT) hormone reserve in different severity of atrophic autoimmune thyroiditis (AAT). Forty-eight female patients with AAT were divided into four groups based on basal and peak thyrotropin (TSH) values (after oral thyrotropin-releasing hormone [TRH], free triiodothyronine (FT3) and free thyroxine (FT4) ranging from normal in group 1 to overt hypothyroidism in group 4. All had thyroid antibodies. The control group comprised euthyroid females of comparable age, without thyroid antibodies. Basal CT and CT response to calcium infusion (area under the curve) were investigated as parameters of CT reserve. Basal CT was lower in groups 2 to 4 of patients with AAT (compared to controls), but the difference was not significant. Stimulated CT levels were lower (p < 0.05) in all groups of patients compared to controls, with markedly reduced CT-secretory reserve in group 4. Thyroid antibody concentrations and, basal and postinfusion calcium levels were not significantly different among the various groups. In conclusion CT deficiency (especially stimulated values) occurs in AAT and is more severe in hypothyroid patients than in earlier stages of AAT.

Calcitonin reserve in different stages of atrophic autoimmune thyroiditis.

Bisphosphonates in breast cancer and other solid tumors

Circulating interleukin-6 (IL-6) concentrations correlate with disease activity in severe inflammatory conditions, in sepsis and in some hematological malignancies. On the other hand, IL-6 is a potent stimulator of osteoclastogenesis and has been implicated as a contributory factor in the genesis of osteopenic conditions. We measured circulating IL-6 levels by a sensitive (detection limit of 10 U/ml) and specific bioassay in 103 patients with advanced cancer, including 41 with tumor-induced hypercalcemia before any specific hypocalcemic therapy. We related IL-6 concentrations to clinical features and to biochemical parameters of bone metabolism, including blood Ca, Ca2+, Pi, intact parathyroid hormone, parathyroid hormone-related protein, osteocalcin, 1,25-(OH)2-vitamin D and, as markers of bone resorption, the fasting urinary excretion of calcium (Ca/creatinine) and hydroxyproline. IL-6 levels were increased, i.e. detectable, in 23% of the patients, 8/41 (20%) hypercalcemic and 16/62 (26%) normocalcemic patients (NS); the distribution of the values was similar in the two groups. The presence of increased IL-6 concentrations was not related to any clinical characteristic, notably not to the survival nor to the existence of bone metastases, whether in hypercalcemic or normocalcemic patients; e.g., only 3/12 (25%) hypercalcemic subjects without bone metastases had elevated IL-6 levels. We found no significant correlations between IL-6 concentrations and any of the biochemical parameters studied. Hypercalcemic subjects with increased IL-6 had higher urinary Ca/creatinine levels than patients with normal IL-6 levels (P<0.005) but this was not the case in normocalcemic subjects. Mean concentrations of inflammatory or other bone metabolism markers were not significantly different between patients with normal or with elevated IL-6 levels. In summary, circulating IL-6 levels were increased in 23% of 103 patients with advanced cancer, but the frequency of increased IL-6 concentrations was not related to the presence of hypercalcemia or to any marker of calcium metabolism or bone turnover. The pathogenic importance of circulating IL-6 in patients with solid tumors remains to be demonstrated and our data indicate that increased circulating levels of IL-6, possibly reflecting the activation of the immune system, only contribute in a minor way to the osteolytic process in patients with tumor-induced hypercalcemia.

Jean-Jacques Body

Papers

Sequence- and concentration-dependent effects of acute and long-term exposure to the bisphosphonate ibandronate in combination with single and multiple fractions of ionising radiation doses in human breast cancer cell lines

Regulation of lymphocyte calcitonin receptors by interleukin-1 and interleukin-6.

Calcitonin reserve in different stages of atrophic autoimmune thyroiditis.

Bisphosphonates in breast cancer and other solid tumors

Circulating concentrations of interleukin-6 in cancer patients and their pathogenic role in tumor-induced hypercalcemia.