Heterogeneity in response to treatment with buthionine sulfoximine or interferon in human malignant glioma cells.

Two tumor cell lines were established from each of three human malignant glioma biopsy specimens (M059, M067, M071) and sensitivity to treatment with radiation or chemotherapeutic agents (BCNU, nitrogen mustard) was determined. The effects of recombinant human interferon-alpha (rIFN) on the radiation response and of buthionine sulfoximine (BSO) on the drug response were investigated as well. For tumor M059, two cell lines that differed significantly in radiosensitivity were isolated (surviving fractions at 2 Gy = 0.02 and 0.64). The chemosensitivity and response to chemical modification differed as well. Cell lines established from tumor M071 differed in their response to rIFN only and were not sensitized by BSO. M067 cell lines showed little difference and were not sensitized by either agent. These results suggest that differences may exist both within and among human malignant gliomas with regard to their sensitivity to drugs, radiation, and the ability of chemical agents to modify treatment responses.     

IMRT for breast. a planning study.

BACKGROUND AND PURPOSE: To evaluate the performance of ten different treatment-planning systems when intensity modulated (IMRT) plans are designed for breast treatments that include the irradiation of the internal mammary chain. PATIENTS AND METHODS: A dataset of five patients (CT images and volumes of interest) was distributed to design IMRT plans on the ten systems. To minimise biases, the same geometry and clinical planning aims were imposed on the individual plans. Results were analysed in terms of dose distributions and dose volume histograms. RESULTS AND CONCLUSIONS: For target coverage, the volume receiving more than 95% of the prescribed dose ranged from 77% (OTP) to 91% (Eclipse and Pinnacle), the volume receiving more than 107% ranged from 3.3% (Hyperion) to 23.2% (OTP). The mean dose to ipsilateral lung ranged from 13 Gy (Eclipse) to 18 Gy (OTP). The volume of the contralateral breast receiving more than 10 Gy ranged from 3% (Pinnacle) to 26% (Precise). The volume of heart receiving more than 20 Gy ranged from 7% (Eclipse) to 47% (Precise), the maximum significant dose to heart ranged from approximately 27 Gy (XiO) to approximately 49 Gy (Precise). The maximum significant dose to healthy tissue ranged from approximately 51 Gy (Eclipse) to approximately 62 Gy (OTP). It was also possible to show that the treatment geometry proposed here enables to minimise contralateral breast irradiation while keeping minimal ipsilateral lung (or heart) involvement and satisfactory target coverage.     

The Erve Virus: Possible Mode of Transmission and Reservoir

Summary The Erve virus is suspected to cause severe headache in humans, lasting several days (thunderclap headache). Mice are characterized as a probable reservoir for the Erve virus. We tested 396 wild mice for Erve virus using an immunofluorescence test and found Erve virus antibodies in five cases, showing that small mammals form a reservoir for Erve virus. If ticks are the vector for the virus, a coincidence with borreliosis should exist. We were unable to confirm this in a homogeneous cohort of 955 young men, 62 of whom tested positive for borreliosis. This group did not test positive significantly more often in the immunofluorescence test than a gender- and age-matched control group. Received: October 1, 1999 · Revision accepted: February 23, 2000     

Community-wide convergent evolution in insect adaptation to toxic cardenolides by substitutions in the Na,K-ATPase

The extent of convergent molecular evolution is largely unknown, yet is critical to understanding the genetics of adaptation. Target site insensitivity to cardenolides is a prime candidate for studying molecular convergence because herbivores in six orders of insects have specialized on these plant poisons, which gain their toxicity by blocking an essential transmembrane carrier, the sodium pump (Na,K-ATPase). We investigated gene sequences of the Na,K-ATPase α-subunit in 18 insects feeding on cardenolide-containing plants (spanning 15 genera and four orders) to screen for amino acid substitutions that might lower sensitivity to cardenolides. The replacement N122H that was previously shown to confer resistance in the monarch butterfly (Danaus plexippus) and Chrysochus leaf beetles was found in four additional species, Oncopeltus fasciatus and Lygaeus kalmii (Heteroptera, Lygaeidae), Labidomera clivicollis (Coleoptera, Chrysomelidae), and Liriomyza asclepiadis (Diptera, Agromyzidae). Thus, across 300 Myr of insect divergence, specialization on cardenolide-containing plants resulted in molecular convergence for an adaptation likely involved in coevolution. Our screen revealed a number of other substitutions connected to cardenolide binding in mammals. We confirmed that some of the particular substitutions provide resistance to cardenolides by introducing five distinct constructs of the Drosophila melanogaster gene into susceptible eucaryotic cells under an ouabain selection regime. These functional assays demonstrate that combined substitutions of Q(111) and N(122) are synergistic, with greater than twofold higher resistance than either substitution alone and >12-fold resistance over the wild type. Thus, even across deep phylogenetic branches, evolutionary degrees of freedom seem to be limited by physiological constraints, such that the same molecular substitutions confer adaptation.     

Optimierter Einsatz der Strahlentherapie durch IMRT und Präzisionslokalisationsverfahren bei der Behandlung des fortgeschrittenen Prostatakarzinoms

Zusammenfassung Mit der intensitätsmodulierten Strahlentherapie (IMRT) zusammen mit modernen, nichtinvasiven Lokalisationsverfahren steht eine Methodik zur Verfügung, mit der die konformale Bestrahlung des Prostatakarzinoms unter optimaler Schonung des Rektums potentiell verbessert werden kann.Diese Übersicht fasst einerseits die klinischen Erfordernisse an die Strahlentherapie beim fortgeschrittenen Prostatakarzinom und andererseits die neuen nichtinvasiven technischen Möglichkeiten zusammen, die helfen, diese Erfordernisse besser zu erfüllen. Zusammen mit der Diskussion der neuen biologischen Daten, die evtl. die Verkürzung der Radiotherapie ermöglichen, wurde versucht, diese Entwicklungen mit ihren theoretischen Vorteilen und eventuellen Problemen zu schildern, um diese Vorgänge über die Strahlentherapie hinaus transparent zu machen.     

Protective effect of drug delivery systems against the enzymatic degradation of dermally applied DNAzyme

Yet, no standardized test method for drug release measurements from PLGA-based microparticles has been generally agreed on, or described by the regulatory authorities. Often, perfect sink conditions are provided in vitro to avoid artificial drug saturation effects. However, the maintenance of such conditions might strongly affect PLGA degradation. The involved physicochemical processes are complex and the potential impact of perfect sink conditions is not yet well understood. Differently sized, highly porous, carbamazepine- and ibuprofen-loaded PLGA microparticles were prepared by a W/O/W emulsion solvent extraction/evaporation technique. The initial drug loading was intentionally low (3-4%) so that the two drugs were molecularly dispersed within the polymeric matrices (monolithic solutions). This was important to be able to exclude potential limited drug solubility effects on the resulting release kinetics. Drug release into phosphate buffer pH 7.4 was measured under perfect sink conditions. SEC, DSC and SEM were used to characterize polymer degradation. The decrease in the average polymer molecular weight, glass transition temperature as well as changes in the inner and outer morphology of the PLGA microparticles were strongly affected by the bulk fluid's volume. In the case of the poorly water-soluble drug carbamazepine, much lower "microparticle mass:phosphate buffer volume" ratios were required to maintain perfect sink conditions, resulting in stable pH values within the bulk fluid, slower PLGA degradation and, thus, lower drug release rates. Thus, great care has to be taken when defining the conditions for in vitro drug release measurements from PLGA-based microparticles, avoiding potentially artificial conditions for polymer degradation.     

Seroepidemiological study in a Puumala virus outbreak area in South-East Germany

Puumala virus (PUUV) is the cause of the majority of haemorrhagic fever with renal syndrome cases in Germany. In 2004, a nephropathia epidemica outbreak was recorded in Lower Bavaria, South-East Germany. For a seroepidemiological study in this region including the resident population at four locations (n = 178) and soldiers from one location (n = 208) indirect immunoglobulin M (IgM) and immunoglobulin G (IgG) enzyme-linked immunosorbent assays (ELISAs) and immunoblot tests based on a yeast-expressed PUUV nucleocapsid protein were established. The validation using human serum panels originating from Germany revealed a diagnostic sensitivity and specificity of 98/100% for the IgM ELISA, 99/99% for the IgG ELISA, 99/100% for the IgM immunoblot test and 100/96% for the IgG immunoblot test. Using the novel IgG assays as well as a commercial IgG ELISA and an immunofluorescence assay for the resident population an average prevalence of 6.7% (12 of 178) with a range of 0% (0 of 21) to 11.9% (7 of 59) was observed. Positive serological results were equally distributed between males and females with an average age of 63 for males and 52 for females. The seroprevalence in the soldier group was found to be about 1% with one positive male of 203 (age 46 years) and one positive female of five (age 47 years). In conclusion, the PUUV seroprevalence in the residents of the outbreak region in Lower Bavaria was found to be up to fivefold higher than the average hantavirus seroprevalence of the German population.