Intracellular mediators of erucylphosphocholine-induced apoptosis

Induction of apoptosis contributes to the cytotoxic action of the intravenously applicable alkylphosphocholine erucylphosphocholine (ErPC). To define molecular requirements for ErPC-induced apoptosis, activation of caspases-8, -9 and -3 and cleavage of the caspase-3 substrates PARP and ICAD were tested in normal Jurkat T cells, Jurkat cells resistant to death receptor (CD95 or TNFalpha-related apoptosis inducing ligand (TRAIL)-induced apoptosis, Jurkat cells lacking caspase-8 or Fas-associated death domain (FADD) Jurkat cells expressing a dominant-negative caspase-9 or overexpressing Bcl-2 as well as BJAB B-lymphoma cells expressing a dominant-negative FADD (FADD-DN). ErPC induced a time- and dose-dependent apoptotic cell death in Jurkat and BJAB cells, which was characterized by breakdown of the phosphatidylserine asymmetry, depolarization of the mitochondrial membrane potential, release of cytochrome c, activation of caspases-9, -8 and -3, cleavage of PARP and ICAD, as well as chromatin condensation. ErPC-induced apoptosis was independent from CD95-receptor signaling and FADD since CD95- and TRAIL-resistant, caspase-8- and FADD-negative Jurkat cells, as well as BJAB cells expressing FADD-DN were sensitive to ErPC-induced apoptosis. In contrast, inhibition of caspase-9 and overexpression of Bcl-2 significantly reduced ErPC-induced caspase activation and apoptosis. Thus, ErPC triggers apoptosis via a Bcl-2-dependent mitochondrial but death receptor-independent pathway.     

Routine therapeutic drug monitoring in patients treated with 10-360 mg/day citalopram

From data collected during routine TDM, plasma concentrations of citalopram (CIT) and its metabolites demethylcitalopram (DCIT) and didemethylcitalopram (DDCIT) were measured in 345 plasma samples collected in steady-state conditions. They were from 258 patients treated with usual doses (20-60 mg/d) and from patients medicated with 80-360 mg/d CIT. Most patients had one or several comedications, including other antidepressants, antipsychotics, lithium, anticonvulsants, psychostimulants and somatic medications. Dose-corrected CIT plasma concentrations (C/D ratio) were 2.51 +/- 2.25 ng mL-1 mg-1 (n = 258; mean +/- SD). Patients >65 years had significantly higher dose-corrected CIT plasma concentrations (n = 56; 3.08 +/- 1.35 ng mL-1 mg-1) than younger patients (n = 195; 2.35 +/- 2.46 ng mL-1 mg-1) (P = 0.03). CIT plasma concentrations in the generally recommended dose range were [mean +/- SD, (median)]: 57 +/- 64 (45) ng/mL (10-20 mg/d; n = 64), 117 +/- 95 (91) ng/mL (21-60 mg/d; n = 96). At higher than usual doses, the following concentrations of CIT were measured: 61-120 mg/d CIT, 211 +/- 103 (190) ng/mL (n = 93); 121-200 mg/d: 339 +/- 143 (322) ng/mL (n = 70); 201-280 mg/d: 700 +/- 408 (565) ng/mL (n = 18); 281-360 mg/d: 888 +/- 620 (616) ng/mL (n = 4). When only one sample per patient (at the highest daily dose if repeated dosages) is considered, there is a linear and significant correlation (n = 48, r = 0.730; P < 0.001) between daily dose (10-200 mg/d) and CIT plasma concentrations. In experiments with dogs, DDCIT was reported to affect the QT interval when present at concentrations >300 ng/mL. In this study, DDCIT concentration reached 100 ng/mL in a patient treated with 280 mg/d CIT. Twelve other patients treated with 140-320 mg/d CIT had plasma concentrations of DDCIT within the range 52-73 ng/mL. In a subgroup comprised of patients treated with > or =160 mg/d CIT and with CIT plasma concentrations < or =300 ng/mL, and patients treated with < or =200 mg/d CIT and CIT plasma concentrations > or = 600 ng/mL, the enantiomers of CIT and DCIT were also analyzed. The highest S-CIT concentration measured in this subgroup was 327 ng/mL in a patient treated with 140 mg/d CIT, but the highest S-CIT concentration (632 ng/mL) was measured in patient treated with 360 mg/d CIT. In conclusion, there is a highly linear correlation between CIT plasma concentrations and CIT doses, well above the usual dose range.     

Treatment results of childhood acute lymphoblastic leukemia in Austria--a report of 20 years' experience

Between 1981 and 1999, 890 Austrian children with acute lymphoblastic leukemia (ALL) were treated in 5 consecutive trials using protocols from the Berlin-Frankfurt-Münster (BFM) Group. In the trials BFM-A (Austria) 81 and ALL A 84, treatment stratification was performed using a risk factor, which was calculated from the initial peripheral blast cell count, and size of liver and spleen. In the following studies (BFM-A 86, 90 and 95) early response to a 7-day systemic mono-therapy with prednisone (as measured by the peripheral blast cell count) was used as an overriding stratification factor; in order to reduce the need for cranial radiotherapy, all patients received high-dose methotrexate (5 g/m2) for preventive central nervous system treatment. Event-free survival (EFS) rates increased from study BFM-A 81 (n = 141, probability (p) of EFS: 59% +/- 4%) and study ALL A 84 (n = 127, pEFS: 67% +/- 4%) to 77% +/- 4% in trial BFM-A 86 (n = 142), 79% +/- 3% in trial BFM-A 90 (n = 256), and 84% +/- 3% in trial BFM-A 95 (n = 224). However, the prognosis for high-risk patients has not significantly improved within the last 20 years (pEFS: 50%). Furthermore, conventional risk factors such as leukocyte count and age at time of diagnosis, could not be used to indicate patients in the low and intermediate risk group who might eventually relapse. Thus, in trial BFM-A 2000, detection of minimal residual disease by polymerase chain reaction-based methods after 5 and 12 weeks of therapy was introduced for treatment stratification. Minimal residual disease was prospectively shown to predict relapses more precisely and, as a matter of fact, may allow a more exact definition of which patients are at risk and which patients belong to the subgroup with a good prognosis despite reduced treatment.     

Prophylaxis and treatment of neoplastic meningeosis in childhood acute lymphoblastic leukemia

The introduction of cranial radiotherapy (CRT) has provided efficient control of overt or subclinical meningeosis in acute leukemia. Especially due to the long-term toxicity of CRT, reduction or elimination of radiotherapy appeared mandatory after cure rates of more than 70% had been achieved in acute lymphoblastic leukemia (ALL). Several large clinical trials of the Berlin-Frankfurt-Münster (BFM) Study Group with more than 3500 patients since 1981 have demonstrated that intensive systemic and intrathecal chemotherapy without or with limited CRT can efficiently prevent central nervous system (CNS) relapses in a large percentage of patients. However, only in low-risk patients prophylactic radiotherapy can be completely and safely replaced by conventional doses of methotrexate. In addition, reduction of chemotherapy in low-risk ALL increased the rate of relapses with CNS involvement. Thus, only a combination of multidrug induction, high-dose methotrexate (HD-MTX) consolidation, and reintensification allowed safe elimination of CRT in low-risk ALL. This approach combined with CRT with 12Gy and 18 Gy in medium and high risk ALL, respectively, reduced the incidence of relapses with CNS involvement to less than 5% (trial ALL-BFM 86). Patients with inadequate response to therapy, or with T-cell ALL, or with overt CNS disease are at particularly high risk for relapse with CNS involvement, and require more systemic and intrathecal chemotherapy combined with cranial irradiation. In B-cell ALL, short intensive chemotherapy pulses including HD-MTX could completely replace radiotherapy. In AML, post-consolidation CRT appears to be advantageous with regard to control of extramedullary as well as systemic relapses.     

Polyvalent DNA vaccines with bidirectional promoters

The hepatitis B surface antigen (HBsAg) and core antigen (HBcAg) were coexpressed from a synthetic bidirectional promoter with the tetracycline-inactivated transactivator (tTA). The function of this autoregulative system was evaluated following either transfer into established cell lines or intramuscular and intradermal injection of high or low doses of DNA into mice. We measured in vitro antigen expression and in vivo the induction of specific humoral and cellular immune responses. Successful regulation of antigen expression was observed in cultured cells. DNA vaccination with these constructs efficiently primed hepatitis B virus (HBV) specific immunity. However, immunogenic concentrations of the antigens were expressed even in the absence of the transactivator, indicating that low expression level is sufficient to prime an immune response. The bidirectional promoter allows coexpression of either both HBV antigens or a HBV antigen and enhanced green fluorescent protein leading to efficient priming of stable immunity against both antigens. This study demonstrates the potential of synthetic polyvalent plasmids in DNA vaccination.     

Inductively coupled rf coils for examinations of small animals and objects in standard whole-body MR scanners

Inductively coupled solenoid coils fitting to objects in the size of mice or rats were developed to adapt modem whole-body MR scanners featuring sufficient gradient strength for animal examinations with high spatial resolution. Homogenous receiver characteristics is achievable over almost the whole inner region of the solenoid coils. The SNR can be increased by a factor 2 to 6 with the adapting coils for examinations using the head coil as connected receiver. Standard sequences on clinical 1.5 T scanners can be applied with adapted transmitter voltages. For example, a SNR value of about 30 is achievable in a mouse liver after 10 minutes measuring time using a 2-D spin echo imaging sequence and a size of 0.3 x 0.3 x 0.8 mm3 for the picture elements.     

Sudden cardiovascular death associated with sexual activity

In recent discussions about potency-enhancing drugs such as sildenafil, health hazards associated with sexual activity have attracted increasing attention (1). In a medicolegal postmortem study performed in the Center of Legal Medicine at the University Hospital in Frank furt/Main over a 33-year period (1972–2004), about 32,000 forensic autopsies revealed 68 (0.22%) natural deaths occurring during sexual activity. Except for 5 women (7.4%; average age 39.8 years), in most cases, men were involved (92.6%; average age 59.1 years). The most frequent cause of death was myocardial infarction (n=28; 41.2%). In three cases, pericardial tamponade accompanied by myomalacia were observed. In 20 patients (29.4%), coronary artery disease (CAD) without signs of acute myocardial infarction (MI) was diagnosed. The medical history of 19 of the deceased indicated previous MI. There were seven cerebral hemorrhages (10.3%). The annual incidence of sudden cardiovascular death during sexual activity is estimated to be 1.9 per 1000 autopsies for men and 0.16 per 1000 autopsies for women (1). It is necessary to inform patients with CAD about prodromes and risk in relation to any form of physical and/or emotional stress. This study was presented at the Sixth International Symposium in Advanced Legal Medicine (ISALM), Hamburg, Germany, September 2006.     

A Small Prospective Study of Chordomas Treated with Radiotherapy and Razoxane

PURPOSE: To evaluate the local effect of conventional photon irradiation in chordomas if the radiosensitizing agent razoxane is added. The rationale for this procedure were improved results previously seen in soft tissue and chondrosarcomas with this combination. PATIENTS AND METHODS: Between 1988 and 1996, five patients with histologically confirmed chordomas of the skull base or the spine (three females, two males) were irradiated with 6- and 25-MeV photons under razoxane medication, one patient was treated with a telecobalt unit. Single doses of 180-200 cGy were given five times a week. The median total tumor dose was 63 Gy (range 54-67 Gy). Concomitantly, the radiosensitizer razoxane was administered at a dose of 125 mg twice daily p.o., median total dose 7.6 g. The drug was started 3-5 days before the first irradiation, and continued until the end of radiotherapy. RESULTS: After a potential median follow-up time of 10 years, three of the five patients are alive and show neither symptoms nor signs of recurrence in CT or MR images. One patient with persistent sacral chordoma died after 8 years from cardiac insufficiency, and another patient died after 6.5 years from a bleeding complication following surgery for recurrence. The patients remained locally controlled for 5, 5.5+, 6.4, 11+, and 13+ years, respectively. Objective tumor regressions were noted in three of four patients with measurable disease. Acute side effects included mucosal reactions, two of five patients developed a leukopenia WHO grade 3 due to razoxane. Serious long-term complications were not observed. CONCLUSIONS: Although the patient series is small, there is an interesting trend in local control and survival. The cases are unselected, and the follow-up time is of considerable duration. The treatment can easily be performed at any institution and is tolerated fairly well.     

rf enhancement and shielding in MRI caused by conductive implants: dependence on electrical parameters for a tube model

Radio frequency (rf) eddy-currents induced in implants made of conductive material might cause significant image artifacts in magnetic resonance imaging (MRI) such as shielding of the lumen of vascular stents. rf alteration near metal parts was assessed theoretically in the approximation of alternating current electrodynamics: The implant was modeled as tube with diameter d(o), resistance R, and reactance Y, constituting the secondary winding of a transformer. The transmitter coil of the scanner acted as primary winding and generated the linearly polarized rf field B1,app. Tube axis was assumed parallel to B1,app. The results of the calculations were as follows: Ninety percent of the applied rf-field amplitude is reached in the lumen at a ratio chi=R/Y approximately 2. A rapid drop occurs with the reduction of chi, whereas a further increase of chi causes only a small effect. With chi approximately 1/d(o)(Y approximately d2o,R approximately d(o)), conditions for rf alteration clearly depend on the diameter of the tube. Inside tubes with smaller diameter, rf shielding is less pronounced. rf alteration increases in good approximation with the square root of the strength of the static field B0. The following experiments were carried out: Tubes of similar diameter (d(o) approximately 8 mm) made of material of different conductivity (Cu, Nitinol, carbon fiber reinforced plastic with three different fiber structures) were examined at B0=0.2 and 1.5 T in water phantoms. Tube axis was aligned perpendicular to B0 and spin-echo technique was applied. Local rf enhancement near the outer surface of the metal tubes was detected applying manual reduction of the transmitter amplitude. Shielding inside a carbon fiber tube with d(o) approximately 8 mm and inside a smaller tube with d(o)=3.3 mm was compared. Both tubes showed the same wall structure and thickness (d(w)=0.4 mm). All measurements confirmed the theoretical results. Consequences for the construction of vascular stents are discussed, as well as problems with image artifacts due to rf enhancement near solid conductive implants.