Cryptic lineage differentiation among Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the northwest Indian Ocean.

Phylogeography can provide insight into the potential for speciation and identify geographic regions and evolutionary processes associated with species richness and evolutionary endemism. In the marine environment, highly mobile species sometimes show structured patterns of diversity, but the processes isolating populations and promoting differentiation are often unclear. The Delphinidae (oceanic dolphins) are a striking case in point and, in particular, bottlenose dolphins (Tursiops spp.). Understanding the radiation of species in this genus is likely to provide broader inference about the processes that determine patterns of biogeography and speciation, because both fine-scale structure over a range of kilometers and relative panmixia over an oceanic range are known for Tursiops populations. In our study, novel Tursiops spp. sequences from the northwest Indian Ocean (including mitogenomes and two nuDNA loci) are included in a worldwide Tursiops spp. phylogeographic analysis. We discover a new 'aduncus' type lineage in the Arabian Sea (off India, Pakistan and Oman) that diverged from the Australasian lineage ∼261 Ka. Effective management of coastal dolphins in the region will need to consider this new lineage as an evolutionarily significant unit. We propose that the establishment of this lineage could have been in response to climate change during the Pleistocene and show data supporting hypotheses for multiple divergence events, including vicariance across the Indo-Pacific barrier and in the northwest Indian Ocean. These data provide valuable transferable inference on the potential mechanisms for population and species differentiation across this geographic range.

Motion-vector optimization of control grid interpolation and overlapped block motion compensation using iterated dynamic programming.

The application of advanced motion compensation techniques--control grid interpolation (CGI) and overlapped block motion compensation (OBMC)--to video coding systems provides significant performance advantages, terms of compression ratio and visual quality, over traditional block-matching motion compensation. However, the two-dimensional (2-D) interdependence among motion vectors introduced by these compensation frameworks makes the problem of finding rate-distortion optimal motion vectors, computationally prohibitive. Thus, iterative optimization techniques are often used to achieve good compensation performance. While most reported optimization algorithms adopt an approach that uses a block-matching algorithm to obtain an initial estimate and then successively optimize each motion vector, the over-relaxed motion-vector dependency relations often result in considerable performance degradation. In view of this problem, we present a new optimization scheme for dependent motion-vector optimization problems, one based on dynamic programming. Our approach efficiently decomposes 2-D dependency problems into a series of one-dimensional (1-D) dependency problems. We show that a reliable initial estimate of motion vectors can be obtained efficiently by only considering the dependency in the rate term. We also show that at the iterative optimization stage an effective logarithmic search strategy can be used with dynamic programming to reduce the necessary complexity involved in distortion computation. Compared to conventional iterative approaches, our experimental results demonstrate that our algorithm provides superior rate and distortion performance while maintaining reasonable complexity.

Intravenous cytokine gene delivery by lipid-DNA complexes controls the growth of established lung metastases.

Local expression of cytokine genes by ex vivo transfection or intratumoral gene delivery can control the growth of cutaneous tumors. However, control of tumor metastases by conventional nonviral gene therapy approaches is more difficult. Intravenous injection of lipid-DNA complexes containing noncoding plasmid DNA can significantly inhibit the growth of early metastatic lung tumors. Therefore, we hypothesized that delivery of a cytokine gene by lipid-plasmid DNA complexes could induce even greater antitumor activity in mice with established lung metastases. The effectiveness of treatment with lipid-DNA complexes containing the IL-2 or IL-12 gene was compared with the effectiveness of treatment with complexes containing noncoding (empty vector) DNA. Treatment effects were evaluated in mice with either early (day 3) or late (day 6) established lung tumors. Lung tumor burdens and local intrapulmonary immune responses were assessed. Treatment with either noncoding plasmid DNA or with the IL-2 or IL-12 gene significantly inhibited the growth of early tumors. However, only treatment with the IL-2 or IL-12 gene induced a significant reduction in lung tumor burden in mice with more advanced metastases. Furthermore, the reduction in tumor burden was substantially greater than that achieved by treatment with recombinant cytokines. Treatment with the IL-2 or IL-12 gene was accompanied by increased numbers of NK cells and CD8+ T cells within lung tissues, increased cytotoxic activity, and increased local production of IFN-gamma by lung tissues, compared with treatment with noncoding DNA. Thus, cytokine gene delivery to the lungs by means of intravenously administered lipid-DNA complexes may be an effective method of controlling lung tumor metastases.

Lipid-DNA complexes induce potent activation of innate immune responses and antitumor activity when administered intravenously.

Cationic lipid-DNA complexes (CLDC) are reported to be safe and effective for systemic gene delivery, particularly to the lungs. However, we observed that i.v. injection of CLDC induced immunologic effects not previously reported. We found that even very low doses of CLDC administered i.v. induced marked systemic immune activation. This response included strong up-regulation of CD69 expression on multiple cell types and systemic release of high levels of Th1 cytokines, from both lung and spleen mononuclear cells. CLDC were much more potent immune activators on a per weight basis than either LPS or poly(I:C). The remarkable potency of CLDC appeared to result from enhancement of the immune stimulatory properties of DNA, since cationic lipids alone were without immune stimulatory activity. Systemic treatment with CLDC controlled tumor growth and significantly prolonged survival times in mice with metastatic pulmonary tumors. NK cells accumulated to high levels in the lungs of CLDC-treated mice, were functionally activated, and released high levels of IFN-gamma. The antitumor activity induced by CLDC injection was dependent on both NK cells and IFN-gamma. Thus, DNA complexed to cationic liposomes becomes highly immunostimulatory and capable of inducing strong antitumor activity when administered systemically.

In vivo tumor transfection with superantigen plus cytokine genes induces tumor regression and prolongs survival in dogs with malignant melanoma.

In vivo transfection of established tumors with immunostimulatory genes can elicit antitumor immunity. Therefore, we evaluated the safety and efficacy of intratumoral injections of a bacterial superantigen with a cytokine gene in dogs with malignant melanoma, a spontaneous and highly malignant canine tumor. 26 dogs with melanoma were treated with lipid-complexed plasmid DNA encoding staphylococcal enterotoxin B and either GM-CSF or IL-2. Dogs were evaluated for treatment-associated toxicity, tumor responses, immunologic responses, and survival times. The overall response rate (complete or partial remissions) for all 26 dogs was 46% (12 of 26), and was highest in patients with smaller tumors. Toxicity was minimal or absent in all dogs. Injected tumors developed marked infiltrates of CD4+ and CD8+ T cells and macrophages, and tumor regression was associated with development of high levels of antitumor cytotoxic T lymphocyte activity in peripheral blood lymphocytes. Survival times for animals with stage III melanomas treated by intratumoral gene therapy were prolonged significantly compared with animals treated with surgical tumor excision only. Thus, local tumor transfection with superantigen and cytokine genes was capable of inducing both local and systemic antitumor immunity in an outbred animal with a spontaneously developing malignant tumor.

Direct activation of porcine endothelial cells by human natural killer cells.

Endothelial cell (EC) activation is a consistent feature of discordant xenograft rejection. Treatment of xenograft recipients with complement inhibitors and xenoreactive natural antibody depletion leads to delayed xenograft rejection associated with a cellular infiltrate comprising up to 20% natural killer (NK) cells. To determine the importance of NK cells in xenograft rejection, we studied EC activation and cytotoxicity in co-cultures containing human NK cells and porcine EC. The addition of freshly isolated NK cells to porcine EC resulted in EC cell activation, characterized by the induction of mRNA and protein for the adhesion molecule E-selectin and the chemotactic cytokine interleukin (IL)-8. The induction of E-selectin and IL-8 occurred with three separate sources of NK cells: purified CD56+ve cells, the NK cell clone B22, and the Fc receptor-deficient NK cell line NK92. Transwell cultures demonstrated that direct NK-EC contact was required for the EC induction of E-selectin and IL-8. These effects could not be inhibited with human recombinant tumor necrosis factor-alpha receptor, and the transfer of supernatants or cell lysates from activated EC to secondary cultures did not result in EC activation. The addition of human IgG enhanced the level of E-selectin expression and cellular cytotoxicity, and resulted in tumor necrosis factor-alpha and interferon-gamma secretion. Thus, human NK cells can lyse or activate EC by direct cell contact and the addition of IgG enhances EC activation and NK cell cytokine secretion. These findings implicate NK cells in EC activation and cell-mediated xenograft rejection.

Prescription for a system.

Health authorities' drug budgets are large and difficult to control. Alan Willson and colleagues outline the system requirements for audit, resource management and costing reports.