A critical role for lymphatic endothelial heparan sulfate in lymph node metastasis

Abstract Background Lymph node metastasis constitutes a key event in tumor progression. The molecular control of this process is poorly understood. Heparan sulfate is a linear polysaccharide consisting of unique sulfate-modified disaccharide repeats that allow the glycan to bind a variety of proteins, including chemokines. While some chemokines may drive lymphatic trafficking of tumor cells, the functional and genetic importance of heparan sulfate as a possible mediator of chemokine actions in lymphatic metastasis has not been reported. Results We applied a loss-of-function genetic approach employing lymphatic endothelial conditional mutations in heparan sulfate biosynthesis to study the effects on tumor-lymphatic trafficking and lymph node metastasis. Lymphatic endothelial deficiency in N-deacetylase/N-sulfotransferase-1 (Ndst1), a key enzyme involved in sulfating nascent heparan sulfate chains, resulted in altered lymph node metastasis in tumor-bearing gene targeted mice. This occurred in mice harboring either a pan-endothelial Ndst1 mutation or an inducible lymphatic-endothelial specific mutation in Ndst1. In addition to a marked reduction in tumor metastases to the regional lymph nodes in mutant mice, specific immuno-localization of CCL21, a heparin-binding chemokine known to regulate leukocyte and possibly tumor-cell traffic, showed a marked reduction in its ability to associate with tumor cells in mutant lymph nodes. In vitro modified chemotaxis studies targeting heparan sulfate biosynthesis in lymphatic endothelial cells revealed that heparan sulfate secreted by lymphatic endothelium is required for CCL21-dependent directional migration of murine as well as human lung carcinoma cells toward the targeted lymphatic endothelium. Lymphatic heparan sulfate was also required for binding of CCL21 to its receptor CCR7 on tumor cells as well as the activation of migration signaling pathways in tumor cells exposed to lymphatic conditioned medium. Finally, lymphatic cell-surface heparan sulfate facilitated receptor-dependent binding and concentration of CCL21 on the lymphatic endothelium, thereby serving as a mechanism to generate lymphatic chemokine gradients. Conclusions This work demonstrates the genetic importance of host lymphatic heparan sulfate in mediating chemokine dependent tumor-cell traffic in the lymphatic microenvironment. The impact on chemokine dependent lymphatic metastasis may guide novel therapeutic strategies

What can cohort studies in the dog tell us?

This paper addresses the use of cohort studies in canine medicine to date and highlights the benefits of wider use of such studies in the future. Uniquely amongst observational studies, cohort studies offer the investigator an opportunity to assess the temporal relationship between hypothesised risk factors and diseases. In human medicine cohort studies were initially used to investigate specific exposures but there has been a movement in recent years to more broadly assess the impact of complex lifestyles on morbidity and mortality. Such studies do not focus on narrow prior hypotheses but rather generate new theories about the impact of environmental and genetic risk factors on disease. Unfortunately cohort studies are expensive both in terms of initial investment and on-going costs. There is inevitably a delay between set up and the reporting of meaningful results. Expense and time constraints are likely why this study design has been used sparingly in the field of canine health studies. Despite their rather limited numbers, canine cohort studies have made a valuable contribution to the understanding of dog health, in areas such as the dynamics of infectious disease. Individual exposures such as neutering and dietary restriction have also been directly investigated. More recently, following the trend in human health, large cohort studies have been set up to assess the wider impact of dog lifestyle on their health. Such studies have the potential to develop and test hypotheses and stimulate new theories regarding the maintenance of life-long health in canine populations

Dogslife: A web-based longitudinal study of Labrador Retriever health in the UK

<p>Abstract</p> <p>Background</p> <p>Dogslife is the first large-scale internet-based longitudinal study of canine health. The study has been designed to examine how environmental and genetic factors influence the health and development of a birth cohort of UK-based pedigree Labrador Retrievers.</p> <p>Results</p> <p>In the first 12 months of the study 1,407 Kennel Club (KC) registered eligible dogs were recruited, at a mean age of 119 days of age (SD 69 days, range 3 days – 504 days). Recruitment rates varied depending upon the study team’s ability to contact owners. Where owners authorised the provision of contact details 8.4% of dogs were recruited compared to 1.3% where no direct contact was possible. The proportion of dogs recruited was higher for owners who transferred the registration of their puppy from the breeder to themselves with the KC, and for owners who were sent an e-mail or postcard requesting participation in the project. Compliance with monthly updates was highly variable. For the 280 dogs that were aged 400 days or more on the 30^th June 2011, we estimated between 39% and 45% of owners were still actively involved in the project. Initial evaluation suggests that the cohort is representative of the general population of the KC registered Labrador Retrievers eligible to enrol with the project. Clinical signs of illnesses were reported in 44.3% of Labrador Retrievers registered with Dogslife (median age of first illness 138 days), although only 44.1% of these resulted in a veterinary presentation (median age 316 days).</p> <p>Conclusions</p> <p>The web-based platform has enabled the recruitment of a representative population of KC registered Labrador Retrievers, providing the first large-scale longitudinal population-based study of dog health. The use of multiple different methods (e-mail, post and telephone) of contact with dog owners was essential to maximise recruitment and retention of the cohort.</p

Understanding foot-and-mouth disease virus transmission biology: identification of the indicators of infectiousness

The control of foot-and-mouth disease virus (FMDV) outbreaks in non-endemic countries relies on the rapid detection and removal of infected animals. In this paper we use the observed relationship between the onset of clinical signs and direct contact transmission of FMDV to identify predictors for the onset of clinical signs and identify possible approaches to preclinical screening in the field. Threshold levels for various virological and immunological variables were determined using Receiver Operating Characteristic (ROC) curve analysis and then tested using generalized linear mixed models to determine their ability to predict the onset of clinical signs. In addition, concordance statistics between qualitative real time PCR test results and virus isolation results were evaluated. For the majority of animals (71%), the onset of clinical signs occurred 3–4 days post infection. The onset of clinical signs was associated with high levels of virus in the blood, oropharyngeal fluid and nasal fluid. Virus is first detectable in the oropharyngeal fluid, but detection of virus in the blood and nasal fluid may also be good candidates for preclinical indicators. Detection of virus in the air was also significantly associated with transmission. This study is the first to identify statistically significant indicators of infectiousness for FMDV at defined time periods during disease progression in a natural host species. Identifying factors associated with infectiousness will advance our understanding of transmission mechanisms and refine intra-herd and inter-herd disease transmission models

Facebooking in "face": Complex identities meet simple databases

Online systems often struggle to account for the complicated self-presentation and disclosure needs of those with complex identities or specialized anonymity. Using the lenses of gender, recovery, and performance, our proposed panel explores the tensions that emerge when the richness and complexity of individual personalities and subjectivities run up against design norms that imagine identity as simplistic or one-dimensional. These models of identity not only limit the ways individuals can express their own identities, but also establish norms for other users about what to expect, causing further issues when the inevitable dislocations do occur. We discuss the challenges in translating identity into these systems, and how this is further marred by technical requirements and normative logics that structure cultures and practices of databases, algorithms and computer programming

Characterisation and modeling of cattle movements in Cameroon

Introduction In sub-Saharan Africa, rapid urbanisation and per capita consumption of animal source foods are expected to accelerate in the short-medium term and to increase the movements of live animals and animal products in the region. In Cameroon, where the livelihood of most of the rural population depends on the agricultural and livestock sector, a wide range of endemic transboundary infectious diseases (TADs) affect livestock production and trade, and have direct detrimental effects on animal, human and environmental health. Livestock mobility represents a central economic activity in the livestock value chain of the country as well as a central strategy of seasonal adaptation to the ecosystem. Livestock movements, however, are also a central driver of infectious diseases dynamics and contacts between livestock populations are major risk factors for disease introduction and circulation. In countries where financial and technical resources are constrained, such as Cameroon, strategic interventions aiming at the surveillance and control of multiple infectious diseases simultaneously are essential for optimising their cost-effectiveness. The overall aim of this study was to apply a methodological framework to contribute to the understanding of cattle movements in Cameroon and of their implications for disease circulation. Methods This project used a variety of epidemiological and statistical methods to characterise cattle movements in the country across different scales. The collection of primary data and information targeted both the formal cattle trade system, across the country, and the informal seasonal transhumance, across the main livestock production areas. Between September 2014 and May 2015 diverse strategies were applied for collecting empirical data and various data sources from multiple Regions of the country were combined. Cattle trade in Cameroon mainly occurs via multiple trading points owned and managed either by the veterinary authorities or the municipalities. A total of 62 livestock markets, and the relevant offices of the Ministry of Livestock, Fisheries and Animal Products (MINEPIA), were targeted for collecting official data on cattle trade referring to a 12-month period ranging between September 2013 and August 2014. Additionally, a questionnaire-based survey with the various livestock markets stakeholders (herders, traders, butchers and veterinary officials) was carried out to collect a variety of information on the cattle market system. During this 9-month period of field work, data on cattle seasonal transhumance were simultaneously collected using a combination of GPS-tracking technology and questionnaire-based survey. Results Volumes of cattle trade, the type of traded animals and their commercial values varied over the year and across the Regions of the country included in this study. Nevertheless, the market supply of live cattle showed similar temporal trends over the year and across the Regions. Although for almost the entire study area the peak of traded animals in the market system was in December 2013, the trade volume was consistently higher during the rainy season (May to September). On the contrary, the reduction in the trade volume during the dry season was accompanied by an opposite trend in the cattle price, with their commercial value being higher during the dry season. Furthermore, a cattle price differential was highlighted between production Regions and high consumption Regions of the country. The highest volume of cattle trade was recorded in the Adamawa Region, which was the main source of cattle for the country while also receiving animals from neighbouring countries, such as Chad and Central African Republic. In contrast, major urban markets in the Littoral and Central Regions were the main receivers of cattle originating from almost all the other areas of the country. Interestingly, the North-West Region appeared to be more independent and isolated within the cattle trade network of Cameroon, particularly receiving few animals from other Regions. Importantly, there was little variation in the structural characteristics of the cattle trade network as well as in its properties across seasons, showing that, despite the seasonality in traded numbers, the network of cattle moving between markets in Cameroon is very stable. This consistent structure of the network over the year increases the robustness of strategic targeted interventions. We found that targeting the top 20% of the most connected markets would significantly reduce the network cohesiveness providing opportunities for strategic disease surveillance, communication and risk mitigation interventions. The centrality of the market within the trading network was also found to be positively associated with the price of live cattle, which tended to be heavily affected by phenotypic characteristics of the traded cattle. The seasonal cattle transhumance has been found as a common and widespread practice for herders attending the market system across whole the study area, highlighting the close relation between formal trading movements and informal pastoral movements across the country. Transhumant herds were observed to undertake migrations across multiple Regions for period exceeding 6 months and showing the potential for multiple types of interactions with domestic and wild animals. Discussion Multiple livestock infectious diseases were identified as being related to the cattle trade system. As neighbouring and non-neighbouring countries were found to be epidemiologically connected it is clear that national strategies for surveillance and control are likely to have limited effectiveness. Regional coordination for designing and implementing prevention and mitigation strategies against infectious diseases is essential to improve animal health also at national level. This study highlights the opportunity for strategic surveillance, control and communication interventions targeting key livestock markets and Regions of Cameroon. Live cattle price and centrality of markets, represented by their connectedness within the trading network, highlights the need to further investigate the links between economic factors and drivers of disease dynamics, such as livestock movements. The complexity of cattle movements in this context was further evidenced by the seasonal transhumance representing an established common mechanism for managing livestock, and closely interacting with the formal trading system as well as with other domestic and wild animal populations. Better data collection and analysis of livestock movements is required for improving the effectiveness of surveillance and control of infectious diseases. Although animal identification and registration systems would represent an ideal step for increasing traceability of cattle movements, enhancing animal health management and the overall competitiveness of the livestock industry, in the short-term a cost-effective intervention should aim at further developing the current data recording and management systems. Pastoralism, for long seen as an economic and environmental activity with little future, also needs to be acknowledged as a key component of the livestock production system in the country and to be considered accordingly in the management of infectious diseases

Development of the larval migration inhibition test for comparative analysis of ivermectin sensitivity in cyathostomin populations

Cyathostomins are the most prevalent parasitic pathogens of equids worldwide. These nematodes have been controlled using broad-spectrum anthelmintics; however, cyathostomin resistance to each anthelmintic class has been reported and populations insensitive to more than one class are relatively commonplace. The faecal egg count reduction test (FECRT) is considered the most suitable method for screening anthelmintic sensitivity in horses, but is subject to variation and is relatively time-consuming to perform. Here, we describe a larval migration inhibition test (LMIT) to assess ivermectin (IVM) sensitivity in cyathostomin populations. This test measures the paralysing effect of IVM on the ability of third stage larvae (L3) to migrate through a pore mesh. When L3 from a single faecal sample were examined on multiple occasions, variation in migration was observed: this was associated with the length of time that the L3 had been stored before testing but the association was not significant. Half maximal effective concentration (EC50) values were then obtained for cyathostomin L3 from six populations of horses or donkeys that showed varying sensitivity to IVM in previous FECRTs. Larvae from populations indicated as IVM resistant by FECRT displayed significantly higher EC50 values in the LMIT than L3 from populations classified as IVM sensitive or L3 from populations that had not been previously exposed to IVM or had limited prior exposure. The analysis also showed that EC50 values obtained using L3 from animals in which IVM faecal egg count reduction (FECR) levels had been recorded as 95%. For one of the populations, time that had elapsed since IVM administration had an effect on the EC50 value obtained, with a longer time since treatment associated with lower EC50 values. These results indicate that the LMIT has value in discriminating IVM sensitivity amongst cyathostomin populations, but several factors were identified that need to be taken into account when executing the test and interpreting the derived data

Mortality in East African shorthorn zebu cattle under one year: predictors of infectious-disease mortality

BACKGROUND: Infectious livestock diseases remain a major threat to attaining food security and are a source of economic and livelihood losses for people dependent on livestock for their livelihood. Knowledge of the vital infectious diseases that account for the majority of deaths is crucial in determining disease control strategies and in the allocation of limited funds available for disease control. Here we have estimated the mortality rates in zebu cattle raised in a smallholder mixed farming system during their first year of life, identified the periods of increased risk of death and the risk factors for calf mortality, and through analysis of post-mortem data, determined the aetiologies of calf mortality in this population. A longitudinal cohort study of 548 zebu cattle was conducted between 2007 and 2010. Each calf was followed during its first year of life or until lost from the study. Calves were randomly selected from 20 sub-locations and recruited within a week of birth from different farms over a 45 km radius area centered on Busia in the Western part of Kenya. The data comprised of 481.1 calf years of observation. Clinical examinations, sample collection and analysis were carried out at 5 week intervals, from birth until one year old. Cox proportional hazard models with frailty terms were used for the statistical analysis of risk factors. A standardized post-mortem examination was conducted on all animals that died during the study and appropriate samples collected. RESULTS: The all-cause mortality rate was estimated at 16.1 (13.0-19.2; 95% CI) per 100 calf years at risk. The Cox models identified high infection intensity with Theileria spp., the most lethal of which causes East Coast Fever disease, infection with Trypanosome spp., and helminth infections as measured by Strongyle spp. eggs per gram of faeces as the three important infections statistically associated with infectious disease mortality in these calves. Analysis of post-mortem data identified East Coast Fever as the main cause of death accounting for 40% of all deaths, haemonchosis 12% and heartwater disease 7%. CONCLUSION: The findings demonstrate the impact of endemic parasitic diseases in indigenous animals expected to be well adapted against disease pressures. Additionally, agreement between results of Cox models using data from simple diagnostic procedures and results from post-mortem analysis underline the potential use such diagnostic data to reduce calf mortality. The control strategies for the identified infectious diseases have been discussed

Метод лабораторного определения параметров устройства гидроимпульсного воздействия

Дана стаття описує лабораторний метод, що визначає: мету, умови, обсяг і порядок проведення досліджень параметрів пристрою гідроімпульсної дії.This article describes the laboratory method that defines: the purpose, conditions, effort and procedure of the researching the device settings of hydroimpulsive impact