The mechanisms underlying the circadian rhythm of the toxicity induced by irinotecan hydrochloride (CPT-11; 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin) were investigated from the viewpoint of the sensitivity of living organisms and the pharmacokinetics of the drug. ICR male mice were housed under standardized light-dark cycle conditions (lights on at 0700, off at 1900) wi...

Camptothecin (CPT) is a cytotoxic quinoline alkaloid endowed with the inhibition of topoisomerase I, an essential enzyme for the normal functioning of DNA. The redox behaviour of CPT was investigated at a glassy carbon electrode using cyclic, differential pulse and square wave voltammetry. It was shown that CPT can undergo reduction in a pH-dependent mechanism. In acid media only one irreversib...

The anterior cingulate gyrus (ACG) is part of a neural network implicated in attention-demanding tasks, such as the experience of pain. However, the regions within the ACG responding to cognitive demands and to painful stimulation are not identical. Since directing attention away from a painful stimulus is known to reduce the perceived pain intensity, we hypothesized that distraction from pain ...

7-Ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxy-camptothecin (irinotecan; CPT-11) is a prodrug activated by carboxylesterase enzymes. We characterized the hydrolysis of CPT-11 by two recently identified human carboxylesterase (hCE) enzymes, hCE-1 and hCE-2. Km and Vmax for hCE-1 and hCE-2 are 43 microM and 0.53 nmol/min/mg protein and 3.4 microM and 2.5 nmol/min/mg protein, respectively....

Few studies in healthy subjects have examined the neuroimmune responses associated with specific experimental pain stimuli, while none has measured multiple biomarkers simultaneously. The aim of the present study was to compare the neuro-immune responses following two common experimental pain stimuli: cold pressor test (CPT) and focal heat pain (FHP). Eight adults participated in two counterbal...

Neural stem cells and progenitor cells migrate selectively to tumor loci in vivo. We exploited the tumor-tropic properties of HB1.F3.C1 cells, an immortalized cell line derived from human fetal telencephalon, to deliver the cDNA encoding a secreted form of rabbit carboxylesterase (rCE) to disseminated neuroblastoma tumors in mice. This enzyme activates the prodrug CPT-11 more efficiently than d...

Camptothecin (CPT)-based drugs always undergo the reversible, pH-dependent lactone ring-opening reaction, yielding the inactive but toxic carboxylate form. Self-assembly strategy provides an effective route for preserving their bio-stability. In this article, nano-sized self-assemblies from CPT-based antitumor drugs were simply built up by directly diluting the stock dimethylsulfoxide solutions...

OBJECTIVE To investigate the clinical efficacy of neoadjuvant chemotherapy (NAC) with irinotecan (CPT-11) and nedaplatin (NED) followed by radical hysterectomy. METHODS Patients with locally advanced cervical cancer (stage Ib2-IIb) were treated with NAC followed by surgery, primary surgery or primary radiotherapy. NAC was usually performed using transuterine arterial chemotherapy (TUAC) or in...

Invariance under the combined transformations of CPT (in any order) is guaranteed in Quantum Field Theory in flat space times due to a basic theorem (CPT Theorem). The currently used formalism of particle physics phenomenology is based on this theorem. However, there may be violations of the basic underlying assumptions of this theorem in models of quantum gravity, namely Lorentz covariance, un...

BACKGROUND [corrected] We investigated anatomical correlates of the card-placing test (CPT) in patients with amnestic mild cognitive impairment (aMCI). METHODS Fifteen aMCI patients underwent part A and part B of the CPT and FDG-PET. The CPT scores and MMSE scores of 29 cognitively normal people were used for comparison. Statistical parametric mapping (SPM) correlation analysis was used to ex...