PREPARE trial: a randomized phase III trial comparing preoperative, dose-dense, dose-intensified chemotherapy with epirubicin, paclitaxel and CMF versus a standard-dosed epirubicin/cyclophosphamide followed by paclitaxel ± darbepoetin alfa in primary breast cancer--results at the time of surgery.

BACKGROUND: Preoperative chemotherapy is a recommended treatment of both primary operable and locally advanced breast cancer. Strategies to improve efficacy include the use of anthracyclines, taxanes, and intensified dose with bone marrow support. PATIENTS AND METHODS: Patients received neoadjuvant epirubicin 90 mg/m(2) plus cyclophosphamide 600 mg/m(2) followed by paclitaxel 175 mg/m(2) (EC→T), each 3-weekly for four cycles (n = 370), or epirubicin 150 mg/m(2) followed by paclitaxel 225 mg/m(2) with pegfilgrastim followed by CMF (cyclophosphamide 500 mg/m(2), methotrexate 40 mg/m(2), fluorouracil 600 mg/m(2)) on days 1 and 8 (E(dd)→T(dd)→CMF), each 2-weekly and for three cycles (n = 363). Patients were randomly allocated to either simultaneous darbepoetin alfa (DA) (n = 356) or none (n = 377). RESULTS: Pathological complete response (pCR) rate (breast) was higher with E(dd)→T(dd)→CMF, 18.7% versus 13.2% with EC→T; P = 0.043, ypT0/Tis; ypN0 was reported in 20.9% versus 14.3% respectively; P = 0.019. Patients with grade 3 tumors and negative hormone receptor status had a significantly higher pCR rate. Mean hemoglobin values maintained higher with DA (13.6 versus 12.6 g/dl). E(dd)→T(dd)→CMF regimen showed more grade 3-4 mucositis, sensory neuropathy, and neurological complaints. Thromboembolic events were more frequent on DA (3% versus 6%; P = 0.055). CONCLUSION: Dose-dense and -intensified neoadjuvant chemotherapy with E(dd)→T(dd)→CMF was potentially superior to EC→T in terms of pCR. Primary use of DA did not affect pCR.

PREPARE trial: a randomized phase III trial comparing preoperative, dose-dense, dose-intensified chemotherapy with epirubicin, paclitaxel, and CMF versus a standard-dosed epirubicin-cyclophosphamide followed by paclitaxel with or without darbepoetin alfa in primary breast cancer--outcome on prognosis.

BACKGROUND: The objective of this study was to compare the effect of dose-intensified neoadjuvant chemotherapy with that of standard epirubicin plus cyclophosphamide followed by paclitaxel in combination with or without darbepoetin on survival in primary breast cancer. PATIENTS AND METHODS: A total of 733 patients received either four cycles of neoadjuvant epirubicin 90 mg/m(2) plus cyclophosphamide 600 mg/m(2) every 3 weeks followed by four cycles of paclitaxel 175 mg/m(2) every 3 weeks (EC→T), or three cycles of epirubicin 150 mg/m(2) every 2 weeks followed by three cycles of paclitaxel 225 mg/m(2) every 2 weeks followed by three cycles of combination chemotherapy with cyclophosphamide, methotrexate, and fluorouracil (E(dd)→T(dd)→CMF). The patients were randomly assigned to receive darbepoetin or none. The primary objective was to demonstrate a superior disease-free survival (DFS) of E(dd)→T(dd)→CMF compared with EC→T. RESULTS: Estimated 3-year DFS was 75.8% with EC→T versus 78.8% with E(dd)→T(dd)→CMF [hazard ratio (HR) 1.14; P = 0.37] and overall survival (OS) 88.4% versus 91.5% (HR 1.26; P = 0.237). Three-year DFS was 74.3% with darbepoetin versus 80.0% without (HR 1.31; P = 0.061) and OS 88.0% versus 91.8% (HR 1.33; P = 0.139). Patients with a pathologically documented complete response [pathological complete response (pCR)] had a significantly better DFS compared with those without achieving a pCR (estimated 3-year DFS: 89.2% versus 74.9%; HR 2.27; P = 0.001). CONCLUSION: Neoadjuvant dose-intensified chemotherapy compared with standard chemotherapy did not improve DFS, whereas the addition of darbepoetin might have detrimental effects on DFS.

Modeling of membrane excitability in gonadotropin-releasing hormone-secreting hypothalamic neurons regulated by Ca2+-mobilizing and adenylyl cyclase-coupled receptors.

Gonadotropin-releasing hormone (GnRH) secretion from native and immortalized hypothalamic neurons is regulated by endogenous Ca(2+)-mobilizing and adenylyl cyclase (AC)-coupled receptors. Activation of both receptor types leads to an increase in action potential firing frequency and a rise in the intracellular Ca(2+) concentration ([Ca(2+)](i)) and neuropeptide secretion. The stimulatory action of Ca(2+)-mobilizing agonists on voltage-gated Ca(2+) influx is determined by depletion of the intracellular Ca(2+) pool, whereas AC agonist-stimulated Ca(2+) influx occurs independently of stored Ca(2+) and is controlled by cAMP, possibly through cyclic nucleotide-gated channels. Here, experimental records from immortalized GnRH-secreting neurons are simulated with a mathematical model to determine the requirements for generating complex membrane potential (V(m)) and [Ca(2+)](i) responses to Ca(2+)-mobilizing and AC agonists. Included in the model are three pacemaker currents: a store-operated Ca(2+) current (I(SOC)), an SK-type Ca(2+)-activated K(+) current (I(SK)), and an inward current that is modulated by cAMP and [Ca(2+)](i) (I(d)). Spontaneous electrical activity and Ca(2+) signaling in the model are predominantly controlled by I(d), which is activated by cAMP and inhibited by high [Ca(2+)](i). Depletion of the intracellular Ca(2+) pool mimics the receptor-induced activation of I(SOC) and I(SK), leading to an increase in the firing frequency and Ca(2+) influx after a transient cessation of electrical activity. However, increasing the activity of I(d) simulates the experimental response to forskolin-induced activation of AC. Analysis of the behaviors of I(SOC), I(d), and I(SK) in the model reveals the complexity in the interplay of these currents that is necessary to fully account for the experimental results.

Magnesium metabolism: basic aspects and implications of ciclosporine toxicity in rats.

In rapidly growing male Sprague-Dawley rats with an initial body weight of 100 +/- 10 g, we investigated how alimentary magnesium (Mg) supply, Mg metabolism and ciclosporine (Ci)-associated nephrotoxicity are interrelated. Food with 100 ppm Mg (1Mg) or 1,000 ppm Mg (stMg) or 10,000 ppm Mg (rMg), Ci 20 mg/kg body weight daily or olive oil were applied for 3 months (n = 10/group). Mg concentrations in various compartments were measured by atomic absorption spectrophotometry. Creatinine clearance (Jaffe), urinary N-acetyl-beta-D-glucosaminidase (NAG) activity (fluorometrically), urinary sodium excretion (flame photometry) and osmolality were measured. Histomorphological examination was done and renal renin expression was studied by monoclonal antibodies. Ci reduced the Mg concentration of the femur under 1Mg (72.6 +/- 9.7 vs. 112.6 +/- 14.3 mmol/kg dry substance, p < 0.05) and under stMg (150.6 +/- 16.6 vs. 194.1 +/- 10.2 mmol/kg dry substance, p < 0.05), thus indicating Ci-related Mg deficiency. This was due to a significant increase in Mg excretion in Ci treatment compared to dietary controls. Under rMg, there was no difference between Ci-treated and control animals. Ci treatment lowered creatinine clearance in 1Mg (1.42 +/- 0.05 vs. 3.02 +/- 0.58 ml/min) and in stMg (1.04 +/- 0.45 vs. 2.18 +/- 0.51 ml/min), NAG/creatinine and urinary sodium excretion were negatively affected by Ci under 1Mg and stMg. Histomorphology showed macrocalcifications due to Mg deficiency and Ci-specific findings, which were markedly enhanced in 1Mg and stMg. Animals with plentiful Mg supply had no functional alterations due to Ci and no or weakly expressed histomorphological lesions. Renin-positive stained cells were higher in Ci-treated animals. This seems to be functionally relevant under 1Mg and stMg, since it was associated with sodium retention and elevated relative heart weight, indicating hypertension. Alimentary or drug-induced Mg deficiency plays a relevant role in the pathophysiology of chronic Ci nephrotoxicity. Our data suggest that Mg supplementation is helpful to reduce Ci toxicity, even if there is 'normal' alimentary Mg intake.