Immunotherapy of murine leukemia. VIII. Efficacy of passive serum therapy of Friend leukemia virus-induced disease in immunocompromised mice

Previous studies have demonstrated that the passive therapy of Friend murine leukemia virus (F-MuLV)-induced disease with chimpanzee anti-F-MuLV serum is accompanied by the development of host antiviral humoral and cellular immunity, the latter measurable in adoptive transfer protocols and by the ability of serum-protected mice to resist virus rechallenge. The present study was designed to further examine the contribution of various compartments of the host immune system to serum therapy itself, as well as to the acquired antiviral immunity that develops in serum-protected mice, through the use of naturally immunocompromised animals [e.g., nude athymic mice and natural killer (NK)-deficient beige mutant mice] or mice treated with immunoabrogating agents such as sublethal irradiation, cyclophosphamide [Cytoxan (Cy)], cortisone, and 89Sr. The studies in nude mice indicate that while mature T-cells are not needed for effective serum therapy, they do appear to be necessary for the long-term resistance of serum-protected mice to virus rechallenge and for the generation of the cell population(s) responsible for adoptive transfer of antiviral immunity. Furthermore, this acquired resistance is not due to virus neutralization by serum antibodies since antibody-negative, Cy-treated, serum-protected mice still reject the secondary virus infection. Lastly, while the immunocompromise systems examined did effect various host antiviral immune responses, none of them, including the NK-deficient beige mutation, significantly diminished the efficacy of the passive serum therapy of F-MuLV-induced disease.     

Competitive quenching: a possible novel approach in protecting RPE cells from damage during PDT

PURPOSE: The purpose of this study is to demonstrate feasibility of using our novel concept, termed competitive quenching, for protecting the choroidal extravascular compartment and retinal pigment epithelium (RPE) from verteporfin (VP)-induced phototoxicity using hypericin. Furthermore, we aim to achieve partitioning of the quencher, hypericin, in the extravascular space and VP within the microvascular compartment of the chorio-retinal complex in vivo. METHODS: We protect RPE cells from damage inflicted by photoactivated VP by introducing hypericin into these cells prior to photosensitization to quench the photosensitizing activity of VP. Cell protection levels were measured by MTT and Hemacolor viability assays. Wavelength range used for VP photoexcitation (700 +/- 40 nm) excludes the absorption range of hypericin, preventing the latter from photoactivation. Pharmacokinetic conditions, in which hypericin spreads throughout the choroidal and retinal extravascular space while VP is confined to the vasculature, are delineated using double-fluorescence imaging. RESULTS: Cell viability increased 3- to 5-fold when 10-20 microM hypericin were present in RPE cells during photosensitization with 0.1-0.5 microM VP. VP fluorescence intensity was unchanged by the presence of hypericin in the cells. Hypericin administered intravenously to rats was confined to the choroidal vasculature after 15 min to 2 hr. Subsequently, hypericin partitioned to the choroidal and retinal extravascular space. VP administered at this time was confined to the microvasculature. CONCLUSIONS: RPE and choroid may potentially be protected by compartmentalizing hypericin to the extravascular compartment while VP administered shortly before photosensitization is confined to the microvasculature. Adverse photodynamic therapy (PDT) damage to choroidal tissues adjacent to neovasculature targeted for photoablation have the potential of being prevented by competitive quenching with hypericin.     

The effect of beclomethasone dipropionate in ultrafine particles on bronchial hyper-reactivity in young children

Aim: Bronchial hyper‐reactivity (BHR) provides a tool for asthma diagnosis, assessment of severity and response to treatment. The effect of beclomethasone dipropionate in ultrafine particles (BDP‐HFA) on BHR as measured by the adenosine challenge test in young children has not yet been determined. Our aim was to determine the effect of BDP‐HFA (100 μg twice daily) on BHR as evaluated by a reduction of 20% from baseline FEV1 (PC20‐FEV1) values in young asthmatic children. Methods: Twenty‐one young children (13 males), mean age 4.95 ± 1.05 years, with partially controlled or controlled asthma completed a double‐blind randomized, placebo‐controlled, cross‐over study. Each child received 4 weeks of treatment with either 100 μg BDP‐HFA twice daily or placebo, and after a 2‐week washout period the other way around. Primary outcomes were PC20‐FEV1 concentration, and the stage number at which FEV1 values dropped by 20%. Results: Following 4 weeks of treatment, median PC20‐FEV1 was 81.28 mg/mL while on BDP‐HFA, compared with 9.64 mg/mL on placebo (p < 0.001). The median increase in stages required to achieve PC20 on BDP‐HFA compared with placebo was three (95% CI 2.28–4.86). Conclusion: Four weeks of treatment with BDP‐HFA resulted in significantly decreased BHR in young children.     

An optimal brain can be composed of conflicting agents

Many behaviors have been attributed to internal conflict within the animal and human mind. However, internal conflict has not been reconciled with evolutionary principles, in that it appears maladaptive relative to a seamless decision-making process. We study this problem through a mathematical analysis of decision-making structures. We find that, under natural physiological limitations, an optimal decision-making system can involve "selfish" agents that are in conflict with one another, even though the system is designed for a single purpose. It follows that conflict can emerge within a collective even when natural selection acts on the level of the collective only.     

Strigolactone analogues induce apoptosis through activation of p38 and the stress response pathway in cancer cell lines and in conditionally reprogramed primary prostate cancer cells.

Strigolactones are a novel class of plant hormones produced in roots and regulate shoot and root development. We have previously shown that synthetic strigolactone analogues potently inhibit growth of breast cancer cells and breast cancer stem cells. Here we show that strigolactone analogues inhibit the growth and survival of an array of cancer-derived cell lines representing solid and non-solid cancer cells including: prostate, colon, lung, melanoma, osteosarcoma and leukemic cell lines, while normal cells were minimally affected. Treatment of cancer cells with strigolactone analogues was hallmarked by activation of the stress-related MAPKs: p38 and JNK and induction of stress-related genes; cell cycle arrest and apoptosis evident by increased percentages of cells in the sub-G1 fraction and Annexin V staining. In addition, we tested the response of patient-matched conditionally reprogrammed primary prostate normal and cancer cells. The tumor cells exhibited significantly higher sensitivity to the two most potent SL analogues with increased apoptosis confirmed by PARP1 cleavage compared to their normal counterpart cells. Thus, Strigolactone analogues are promising candidates for anticancer therapy by their ability to specifically induce cell cycle arrest, cellular stress and apoptosis in tumor cells with minimal effects on growth and survival of normal cells.     

Brain neurons and glial cells express Neu differentiation factor/heregulin: a survival factor for astrocytes.

Neu differentiation factor (NDF, also called heregulin) was isolated from mesenchymal cells on the basis of its ability to elevate phosphorylation of ErbB proteins. Earlier in situ hybridization analysis showed that NDF was transcribed predominantly in the central nervous system during embryonic development. To gain insights into the role of NDF in brain we analyzed its distribution by immunohistochemistry and in situ hybridization. Late-gestation (day 17) rat embryos displayed high NDF immunoreactivity in both motor (e.g., putamen) and limbic (e.g., septum) regions. Lower levels of the factor were exhibited by adult brain, except for the cerebellum, where NDF expression was increased postnatally. Both neurons and glial cells were identified by immunohistochemistry as NDF-producing cells (e.g., pyramidal neurons in the cerebral cortex and glial cells in the corpus callosum). By establishment of primary cultures of rat brain cells we confirmed that NDF was expressed in neurons as well as in astrocytes. In addition, by using such primary cultures we observed that NDF treatment exerted only a limited mitogenic effect, which was accompanied by significant acceleration of astrocyte maturation. Furthermore, long-term incubation with the factor specifically protected astrocytes from apoptosis, implying that NDF functions in brain as a survival and maturation factor for astrocytes.     

Experimental approaches to hypothetical hormones: detection of a candidate ligand of the neu protooncogene.

There is a growing list of oncogenes encoding transmembrane tyrosine kinases that have structures reminiscent of growth factor receptors. In most cases, the ligands for these putative receptors are unknown. Using the neu oncogene as a model system, we have developed several experimental approaches for the detection of such hypothetical ligands. The following lines of evidence collectively imply that a candidate ligand of the neu-encoded oncoprotein is secreted by ras-transformed fibroblasts: Medium conditioned by ras transformants is able to induce down-modulation of the neu-encoded p185 and to activate its intrinsic tyrosine kinase activity in vitro. In addition, a rapid increase in the phosphorylation in vivo of tyrosine residues of the neu-encoded protein is induced by the conditioned medium. Finally, transfer of the neu gene into hematopoietic cells renders them mitogenically responsive to the conditioned medium. The possibility of indirect activation of the oncoprotein through other known receptors, especially the receptor for the epidermal growth factor, was experimentally excluded.