Ajoene, an experimental anti-leukemic drug: mechanism of cell death.

The organosulfur compound ajoene, a constitutent of garlic, has been shown to induce apoptosis in a leukemic cell line as well as in blood cells of a leukemic patient. The mechanisms of action of ajoene, however, are unknown. The present study aims to characterize the molecular events leading to ajoene-triggered apoptosis. We show here that ajoene (20 microM) leads to a time-dependent activation of caspase-3-like activity as well as to the proteolytic processing of procaspase-3 and -8. Activation of caspases was necessary for ajoene-induced apoptosis since the broad-range caspase inhibitor zVAD-fmk completely abrogated ajoene-mediated DNA fragmentation. Although the initiator caspase-8 was activated, the CD95 death receptor was not involved in death signaling since the HL-60 clone used was shown to express a functionally inactive CD95 receptor. Furthermore, ajoene induced the release of cytochrome c, which was not inhibited by zVAD-fmk indicating that cytochrome c release precedes caspase activation. Ajoene also led to a dissipation of the mitochondrial transmembrane potential. Overexpression of Bcl-x(L) clearly diminished ajoene-induced caspase activation as well as apoptosis. These results indicate that apoptosis in leukemia cells triggered by ajoene is based on the activation of a mitochondria-dependent caspase cascade which includes also the activation of the initiator caspase-8.     

Unerwünschte Wirkungen einer zytostatischen Chemotherapie bei Patienten mit Kopf-Hals-Karzinomen ¶ Prophylaxe und Therapie

Ziel des Artikels ist es nicht, internistisch-onkologisches Lehrbuchwissen zu ersetzen, sondern für die klinische Routine eine Basisinformation zur Prophylaxe und Therapie unerwünschter Wirkungen einer zytostatischen Chemotherapie bei Kopf-Hals-Karzinomen zu geben. Hierzu werden im 1. Abschnitt generelle Empfehlungen zur Vermeidung unerwünschter Wirkungen im Umgang mit Zytostatika dargestellt. Im 2. Abschnitt soll auf die Besonderheiten der heute bei Kopf-Hals-Karzinomen zugelassenen Substanzen eingegangen werden mit entsprechenden substanzspezifischen Empfehlungen zur Prophylaxe und Therapie unerwünschter Wirkungen. Im 3. Abschnitt werden spezielle supportive Therapieverfahren zur Behandlung bzw- Vermeidung unerwünschter Wirkungen einer zytostatischen Chemotherapie abgehandelt, die unabh?ngig von der jeweiligen Substanz eingesetzt werden k?nnen.     

Noninvasive measurement of bone strontium.

The strontium content of bone has hitherto been impossible to measure noninvasively. A novel dual-photon absorptiometry (DPA) method was developed. 241Am (59.5 keV) and 133Ba (356 keV) were used as radiation sources. The linearity of the DPA method was studied in monkey bones ex vivo after treatment over 52 wk with strontium ranelate. The bone strontium expressed in terms of the percentage molar ratio SrHA/(SrHA + CaHA) x 100%, where HA denotes hydroxyapatite, was measured (1) by the DPA method and (2) by inductively coupled plasma-atomic emission spectrophotometry at the same distal site of the femur. The results correlated significantly: y = 0.33%Sr + 1.086x; r = 0.976; standard error of the estimate (SEE) = 0.57%Sr. In order to measure the accuracy error of Sr%, 30 normal volunteers were measured. Their mean values did not differ significantly from zero and the SD was 0.5%. The radiation dose was small, the equivalent whole-body dose to human subjects being 0.005 micro Sv. This novel DPA method is likely to be successful for bone strontium measurement in humans.     

Lack of mutations in the epsilon-sarcoglycan gene in patients with different subtypes of primary dystonias.

Primary dystonias represent a clinically and genetically heterogeneous group of movement disorders. Mutations in the epsilon-sarcoglycan (SGCE) gene have been found recently to cause myoclonus-dystonia (MD). Considerable clinical variation of SGCE mutation carriers leads to the hypothesis that mutations in the SGCE gene might also be relevant for other subtypes of dystonias. To determine the contribution of mutations in the SGCE gene in patients with different subtypes of dystonias, we analyzed the coding sequence of the SGCE gene in a group of 296 patients with a clinical phenotype of primary dystonia and in 2 patients with a clinical phenotype of myoclonus-dystonia. Patients with mutations in the DYT1 gene were excluded. We could not detect a mutation in the SGCE gene in any of the 298 patients. Our results suggest that mutations in the SGCE gene cannot be held responsible for other subtypes of primary dystonia.     

Evaluation of HMG-CoA reductase inhibitors for multiple sclerosis: opportunities and obstacles

The disease-modifying agents currently used in the treatment of multiple sclerosis (MS) are not completely effective and are associated with adverse effects and high costs. Thus, alternative treatment options are highly desirable. HMG-CoA reductase inhibitors (statins), widely prescribed as cholesterol-lowering agents, may be a future treatment option for MS--either in an add-on therapy regimen or alone--as they have been shown to exhibit potent immunomodulatory effects. Several recent reports have demonstrated that HMG-CoA reductase inhibitors prevent and reverse chronic and relapsing experimental autoimmune encephalomyelitis, an animal model of MS. Furthermore, in vitro experiments with human immune cells have shown an immunomodulatory mode of action of HMG-CoA reductase inhibitors that is comparable to that of interferon-beta, an established treatment for MS. An open-label clinical trial assessing simvastatin treatment in patients with MS revealed a significant decrease in the number and volume of new lesions, as assessed using magnetic resonance imaging, and a favourable safety profile. A large multicentre, placebo-controlled phase II clinical trial assessing atorvastatin in patients with a clinically isolated syndrome (i.e. a single clinical event that is indicative of demyelination, and that predisposes to the development MS) has recently been initiated. However, prospective placebo-controlled trials of HMG-CoA reductase inhibitors in definite MS are difficult to perform because of ethical and financial issues. Furthermore, overly optimistic reports in the popular media, as well as the often uncontrolled access to HMG-CoA reductase inhibitors by patients with MS, complicate the evaluation of HMG-CoA reductase inhibitors as a realistic future treatment option for MS.     

Magnetic Marker Monitoring: An application of biomagnetic measurement instrumentation and principles for the determination of the gastrointestinal behavior of magnetically marked solid dosage forms

Magnetic Marker Monitoring offers an alternative to investigate the behavior of solid dosage forms in the organs of the gastrointestinal tract without the need to apply radiation. For Magnetic Marker Monitoring, the dosage form is marked as a permanent magnetic dipole by the incorporation of small amounts of ferromagnetic material, as for example the colorant black iron oxide, and subsequent magnetization. Thereby, the dosage form is labeled as the source of a well defined magnetic field, which can be measured using a measurement technique that is established for biomagnetic investigations. Using the established concepts for magnetic source localization, the three dimensional localization and orientation as well as the strength of the magnetic source can be reconstructed from these magnetic measurement data as a function of time. Furthermore, it is possible to gain quantitative information on the disintegration of dosage forms in vivo. Examples are given for results obtained concerning the esophageal transit, the gastric and the intestinal behavior of capsules and tablets.     

Association of circulating interleukin (IL)-12- and IL-10-producing dendritic cells with time posttransplant, dose of immunosuppression, and plasma cytokines in renal-transplant recipients

BACKGROUND: Interleukin (IL)-12-producing dendritic cells (IL-12+DC) polarize T helper (Th) differentiation toward Th1, whereas IL-10+DC induce Th differentiation toward Th2. We investigated DC and plasma cytokine patterns early and late after transplantation. METHODS: Twenty-five hospitalized renal-transplant recipients without acute rejection or infection early (<40 days) posttransplant, 32 symptom-free outpatients with long-term functioning transplants (2,762+/-2,423 days posttransplant), and 17 healthy controls were studied. The intracellular production of IL-12 and IL-10 in CD11c+ CD83+ CD40+ DC was measured in freshly obtained whole blood using four-color fluorescence flow cytometry. In addition, plasma cytokine levels were investigated. RESULTS: Early and late posttransplant patients had significantly lower proportions of IL-12+DC (early: P=0.001; late: P=0.034) and lower ratios of IL-12+/IL-10+DC (early: P=0.0001; late: P<0.0001) than healthy controls. IL-10+DC (P=0.0004) and IL-12+DC (P=0.002) increased with time posttransplant in association with dose reductions of cyclosporine (IL-10+DC: P=0.003; IL-12+DC: P=0.005), methylprednisolone (IL-10+DC: P<0.0001; IL-12+DC: P=0.001) and mycophenolate mofetil (IL-10+DC: P<0.0001; IL-12+DC: P=0.004). Both IL-10+DC and IL-12+DC were associated with low plasma IL-10 (IL-10+DC: P=0.010; IL-12+DC: P=0.011) and high plasma IL-6 (IL-10+DC: P=0.001; IL-12+DC: P=0.009). IL-10+DC were also associated with high plasma levels of IL-3 (P=0.003), interferon (IFN)-gamma (P=0.014), and IL-2 (P=0.058). CONCLUSION: IL-10+DC and IL-12+DC in peripheral blood are associated with time after transplantation and dosage of immunosuppression. IL-10+DC dominate late posttransplant in the presence of Th1 plasma cytokines (high IFN-gamma and IL-2), high IL-3, and low IL-10. These findings could be a reflection of immunoregulatory processes favoring long-term allograft acceptance.     

C-mode real-time tomographic reflection for a matrix array ultrasound sonic flashlight

RATIONALE AND OBJECTIVES: Real-time tomographic reflection (RTTR) permits in situ visualization of tomographic images so that natural hand-eye coordination can be used directly during invasive procedures. The method uses a half-silvered mirror to merge the visual outer surface of the patient with a simultaneous scan of the patient's interior without requiring a head-mounted display or tracking. A viewpoint-independent virtual image is reflected precisely into its actual location. When applied to ultrasound, we call the resulting RTTR device the sonic flashlight. We previously implemented the sonic flashlight using conventional two-dimensional ultrasound scanners that produce B-mode slices. Real-time three-dimensional (RT3D) ultrasound scanners recently have been developed that permit RTTR to be applied to slices with other orientations, including C-mode (parallel to the face of the transducer). Such slice orientation may offer advantages for image-guided intervention. MATERIALS AND METHODS: Using a prototype scanner developed at Duke University (Durham, NC) with a matrix array that electronically steers an ultrasound beam at high speed in 3D, we implemented a sonic flashlight capable of displaying C-mode images in situ in real time. RESULTS: We present the first images from the C-mode sonic flashlight, showing bones in the hand and the cardiac ventricles. CONCLUSION: The extension of RTTR to matrix array RT3D ultrasound offers the ability to visualize in situ slices other than the conventional B-mode slice, including C-mode slices parallel to the face of the transducer. This orientation may provide a broader target, facilitating certain interventional procedures. Future work is discussed, including display of slices with arbitrary orientation and use of a holographic optical element instead of a mirror.