Oligoclonal in vitro response of CD4 T cells to vesicles of mistletoe extracts in mistletoe-treated cancer patients

 Mistletoe (Viscum album) extracts are widely used in adjuvant cancer therapy. We have investigated the in vitro responsiveness of T cells from mistletoe-treated cancer patients and untreated healthy donors to various preparations of mistletoe extracts. Proliferation of peripheral blood mononuclear cells from treated but not from untreated patients was observed in response to therapeutically used mistletoe extracts prepared from apple (mali) or pine (pini) host trees. The strongest proliferation was induced by a vesicle preparation of mali extract. Activation was strongly inhibited by interleukin-10. Using a newly developed flow-cytometry assay, we determined that cell growth was restricted to CD4 T cells. Analysis with a panel of monoclonal antibodies against the variable region of the T cell receptor β chain (Vβ) revealed an oligoclonal pattern of CD4 T cell activation. These results indicate that therapeutic administration of mistletoe extracts sensitizes a restricted set of CD4 T lymphocytes in mistletoe-treated patients. Received: 25 May 1996 / Accepted: 9 January 1997     

The concentration of Ca,Sr, Ba and Mn in successive needle age classes of Norway spruce [Picea abies (L.) Karst.]

The concentrations of Ca, Sr, Ba and Mn were determined in up to five successive needle age classes from 54 individual Norway spruce trees [Picea abies (L.) Karst] from nine different sites. The accumulation behaviour was found to be very nonuniform, going from an increase with needle age to a decrease; irregular patterns were also found. The type of accumulation is largely site specific. The increasing behaviour can in most cases be approximated by a simple arithmetic function. All four elements usually show the same accumulation pattern, the similarities being closest between Ca and Mn and least between Ca and Ba. It is postulated that the similarity between the four elements is due to their precipitation and storage as oxalates. The similarity between Ca, Sr and Ba is observed at all concentrations, that with Mn only at concentrations larger than 300 g/g. Mn at small concentrations (< 50 g/g) shows a decreasing pattern and no similarity at all with Ca, Sr and Ba, but behaves similar to mobile elements.     

Elektronenmikroskopische Untersuchungen zur Struktur und Funktion der Rektalpapillen von Drosophila melanogaster

Zusammenfassung Die Zellen der vier Rektalpapillen von Drosophila melanogaster sind polar gebaute, hochdifferenzierte, transportaktive Zellen mit großflächigen Ein- und Ausfaltungen des Plasmalemms. Ihre basale und laterale Zellmembran bildet ein Netzwerk von Einfaltungen, aus dem zahlreiche Stapel von Membranpaaren hervorgehen, die mit Mitochondrien vergesellschaftet sind. Apikal besitzt die Zelle ein System von Mikroleisten, an deren Basis ebenfalls Mitochondrien akkumuliert sind (s. Abb. 9). Bei Drosophila werden nach Durchführung der entsprechenden elektronenmikroskopischen Nachweise Natriumionen an den Membranen der apikalen Ausfaltungen, an den Membranen der interzellulären Stapel der Membranpaare, innerhalb deren Lumina und in den basalen und lateralen Einfaltungen gefunden. Eine bevorzugte Lokalisation von Chloridionen ist nicht vorhanden.Diese Feinstrukturaspekte und die Ergebnisse der Nachweisreaktionen für Natrium und Chloridionen werden mit den Verhältnissen bei Calliphora erythrocephala (Gupta und Berridge, 1966) verglichen und die Transportwege der Ionen eingehend diskutiert.

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Electron microscopic studies on the structure and function of the rectal papillae in Drosophila melanogaster

Summary In Drosophila melanogaster the cells of the rectal papillae are highly differentiated and very active in transport. These cells show extensive infoldings of the plasmalemma. The basal and lateral cell membranes form a system of infoldings, continuous with intracellular stacks of paired membranes which are associated with mitochondria. The apex of the cell displays a system of micro-ridges with basal mitochondria (see Fig. 9). In Drosophila Na⁺ ions can be demonstrated by electron microscopy at the membranes of the apical micro-ridges, at the membranes and within the lumina of the intracellular stacks of paired membranes, and within the basal and lateral infoldings. In contrast, there is no predominant localization of Cl^– ions. The fine structure of the cells of the rectal papillae and the results of cytochemical demonstration of Na⁺ and Cl^– ions are compared with the findings of Gupta and Berridge (1966) in Calliphora erythrocephala. The possible pathways for ion transport are discussed in detail.

Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Using the stable isotope marker 13C to study extrafloral nectar uptake by parasitoids under controlled conditions and in the field

Parasitic wasps are prominent natural enemies of crop pests. They usually feed on floral resources during the adult stage (nectar, pollen, or honeydew). Extrafloral nectar is an alternative source of sugar easily accessible to adult parasitoids. We developed an original method of nectar labelling based on the injection of labelled sugar solution into the plant stem in order to analyse the nectar uptake by parasitoids (cotton wick method). This method was used to artificially enrich extrafloral cornflower, Centaurea cyanus L. (Asteraceae), nectar with the stable isotope ¹³C. We analysed (1) the transfer of ¹³C from the sugar solution into extrafloral nectaries, (2) the uptake of labelled nectar by parasitoids under laboratory conditions, and (3) the ability of the method to discriminate, in an oilseed rape (Brassica napus L., Brassicaceae) field, between labelled parasitoids (i.e., those who have fed on labelled cornflowers located adjacent to the field) and unlabelled parasitoids to track parasitoid movements from the margin into the field. The extrafloral nectar of all test plants was ¹³C‐labelled. Most (66%) of the parasitoids were identified as marked after 96 h of exposure to labelled plants in the laboratory. We could also detect labelled parasitoids inside the field, but the detection rate was only 1%. The experiments clearly demonstrate that the cotton wick method is appropriate to label extrafloral nectar and parasitoids feeding on this labelled nectar. Further research is needed on the amount of labelled extrafloral nectar required to obtain a sufficient marker level to track parasitoid movements in the field.     

A rise of ploidy level influences the rate of cytomixis in tobacco male meiosis

The effect of plant ploidy level on the rate of cytomixis in microsporogenesis has been analyzed with the help of a unique model, the collection of tobacco plants of different ploidies (2n?=?2x?=?24, 4x?=?48, 6x?=?72, and 8x?=?96). As has been shown, the rate of cytomixis proportionally increases in 6x and 8x cytotypes, being rather similar in 2x and 4x plants. The rate of cytomixis is highly variable, differing even in the genetically identical plants grown under the same conditions. The cytological pattern of cytomixis in the microsporogenesis of control 4x plants has been compared with the corresponding patterns of 2x, 6x, and 8x plants. Involvement of cytomixis in production of unreduced gametes and stabilization of the newly formed hybrid and polyploidy genomes is discussed.     

Theory and Experimental Validation of a Spatio-temporal Model of Chemotherapy Transport to Enhance Tumor Cell Kill

It has been hypothesized that continuously releasing drug molecules into the tumor over an extended period of time may significantly improve the chemotherapeutic efficacy by overcoming physical transport limitations of conventional bolus drug treatment. In this paper, we present a generalized space- and time-dependent mathematical model of drug transport and drug-cell interactions to quantitatively formulate this hypothesis. Model parameters describe: perfusion and tissue architecture (blood volume fraction and blood vessel radius); diffusion penetration distance of drug (i.e., a function of tissue compactness and drug uptake rates by tumor cells); and cell death rates (as function of history of drug uptake). We performed preliminary testing and validation of the mathematical model using in vivo experiments with different drug delivery methods on a breast cancer mouse model. Experimental data demonstrated a 3-fold increase in response using nano-vectored drug vs. free drug delivery, in excellent quantitative agreement with the model predictions. Our model results implicate that therapeutically targeting blood volume fraction, e.g., through vascular normalization, would achieve a better outcome due to enhanced drug delivery.

Author Summary

Cancer treatment efficacy can be significantly enhanced through the elution of drug from nano-carriers that can temporarily stay in the tumor vasculature. Here we present a relatively simple yet powerful mathematical model that accounts for both spatial and temporal heterogeneities of drug dosing to help explain, examine, and prove this concept. We find that the delivery of systemic chemotherapy through a certain form of nano-carriers would have enhanced tumor kill by a factor of 2 to 4 over the standard therapy that the patients actually received. We also find that targeting blood volume fraction (a parameter of the model) through vascular normalization can achieve more effective drug delivery and tumor kill. More importantly, this model only requires a limited number of parameters which can all be readily assessed from standard clinical diagnostic measurements (e.g., histopathology and CT). This addresses an important challenge in current translational research and justifies further development of the model towards clinical translation.