Photodynamic Therapy Using Endogenous Photosensitization for Gastrointestinal Tumors

Photodynamic therapy (PDT) is a novel approach in the treatment of carcinomas of the gastrointestinal tract. This review defines PDT, discusses means of photosensitization and considers the mechanisms by which PDT causes cell death of the target tissue while at the same time avoid damage to normal tissues. Additional considerations include the time of PDT application, activation of the photosensitizer, effectiveness and toxicity of PDT, potential need for additional modalities of treatment and concludes with application of PDT principals to the early detection of malignancy. Data regarding the long term effectiveness of PDT for digestive tract adenocarcinomas are lacking because this field is still in its infancy.     

Widespread occurrence in Australian marsupials of neutralizing antibodies to a herpesvirus from a parma wallaby.

Serum neutralizing antibodies to a parma wallaby herpesvirus (PWHV) have been detected in a wide range of marsupials from different locations across Australia, including several islands. A study of 242 animals (mostly macropods) sampled in the wild showed that 23% had antibodies; a significantly higher frequency (41%) of 116 animals in captivity had antibodies, which were generally at higher levels than those of animals in the wild. Antibodies to PWHV were also detected among parma wallabies from a colony on Kawau Island, New Zealand. The highest antibody levels were found in a group of captive tammar wallabies during recurrent outbreaks of clinical infection. It is suggested that PWHV has evolved along with a marsupial host, and that the high antibody levels among captive animals reflects ease of virus transmission due to crowding, or to conditions of stress leading to expression of latent virus.     

The problem and promise of scale in multilayer animal social networks

Scale remains a foundational concept in ecology.Spatial scale,for instance,has become a central consideration in the way we understand landscape ecology and animal space use.Meanwhile,scale-dependent social processes can range from fine scale interactions to co-occurrence and overlapping home ranges.Furthermore,sociality can vary within and across seasons.Multilayer networks promise the explicit integration of the social,spatial,and temporal contexts.Given the complex interplay of sociality and animal space use in heterogeneous landscapes,there remains an important gap in our understanding of the influence of scale on animal social networks.Using an empirical case study,we discuss ways of considering social,spatial,and temporal scale in the context of multilayer caribou social networks.Effective integration of social and spatial processes,including biologically meaningful scales,within the context of animal social networks is an emerging area of research.We incorporate perspectives that link the social environment to spatial processes across scales in a multilayer context.     

Registration of Phlebiopsis gigantea as a Forest Biocontrol Agent in the UK: Recent Experience

The registration of one of the world's first biological control agents for a plant pathogen, in January 1998, after 30 years of field use, is discussed in relation to its approval under the UK Control of Pesticides Regulations 1986. The control agent, Phlebiopsis gigantea (formerly known as Peniophora gigantea), is a common wood-rotting basidiomycete which is applied to the freshly cut surfaces of pine stumps to prevent their colonization by the pathogenic rootrotting fungus Heterobasidion annosum . Unlike many other biocontrol agents, P. gigantea is not a biocide that kills the target organism. Rather, it competes for resources that the pathogen would otherwise use, providing an extension to a naturally occurring process. Experience in securing approval is reviewed, with special reference to the identity of the organism and its natural distribution, and to assessments of the risk its use might pose in the environment. It is suggested that before the formal process of applying for approval of a biocontrol agent begins, there should be procedures for agreeing precise data requirements. These should be based on the type of crop to be treated and the mode of operation and characteristics of the biocontrol organism. This would streamline the registration process.