161 research outputs found
Longitudinal monitoring of Ehrlichia ruminantium infection in Gambian lambs and kids by pCS20 PCR and MAP1-B ELISA
<p>Abstract</p> <p>Background</p> <p>The epidemiology of <it>E. ruminantium </it>infection in extensively managed young animals is not adequately understood. Thus in this study, we monitored the onset (age at first infection) and kinetics of <it>E. ruminantium </it>infection and antibody response in extensively managed newborn lambs and kids at three sites in The Gambia.</p> <p>Methods</p> <p>We used a nested pCS20 PCR and MAP1-B ELISA in a longitudinal study to monitor the onset (age at first infection) and kinetics of <it>E. ruminantium </it>infection and antibody response respectively, in 77 newborn lambs and kids under a traditional husbandry system at three sites (Kerr Seringe, Keneba, Bansang) in The Gambia where heartwater is known to occur. The animals were monitored for field tick infestation and the comparative performance of the two assays in detecting <it>E. ruminantium </it>infection was also assessed.</p> <p>Results</p> <p>The infection rate detected by pCS20 PCR varied between 8.6% and 54.8% over the 162-day study period. Nineteen per cent of the animals in week 1 post-partum tested positive by pCS20 PCR with half of these infections (7/14) detected in the first 3 days after birth, suggesting that transmission other than by tick feeding had played a role. The earliest detectable <it>A. variegatum </it>infestation in the animals occurred in week 16 after birth. Antibodies detected by MAP1-B ELISA also varied, between 11.5% and 90%. Although there is considerable evidence that this assay can detect false positives and due to this and other reasons serology is not a reliable predictor of infection at least for heartwater. In contrast to the pCS20 PCR, the serological assay detected the highest proportion of positive animals in week 1 with a gradual decline in seropositivity with increasing age. The pCS20 PCR detected higher <it>E. ruminantium </it>prevalence in the animals with increasing age and both the Spearman's rank test (<it>r</it><sub><it>s </it></sub>= -0.1512; P = 0.003) and <it>kappa </it>statistic (-0.091 to 0.223) showed a low degree of agreement between the two assays.</p> <p>Conclusion</p> <p>The use of pCS20 PCR supported by transmission studies and clinical data could provide more accurate information on heartwater epidemiology in endemic areas and single-occasion testing of an animal may not reveal its true infection status. The view is supported because both the vector and vertical transmission may play a vital role in the epidemiology of heartwater in young small ruminants; the age range of 4 and 12 weeks corresponds to the period of increased susceptibility to heartwater in traditionally managed small ruminants.</p
Diagnosis of Human Visceral Pentastomiasis
Visceral pentastomiasis in humans is caused by the larval stages (nymphs) of the arthropod-related tongue worms Linguatula serrata, Armillifer armillatus, A. moniliformis, A. grandis, and Porocephalus crotali. The majority of cases has been reported from Africa, Malaysia, and the Middle East, where visceral pentastomiasis may be an incidental finding in autopsies, and less often from China and Latin America. In Europe and North America, the disease is only rarely encountered in immigrants and long-term travelers, and the parasitic lesions may be confused with malignancies, leading to a delay in the correct diagnosis. Since clinical symptoms are variable and serological tests are not readily available, the diagnosis often relies on histopathological examinations. This laboratory symposium focuses on the diagnosis of this unusual parasitic disease and presents its risk factors and epidemiology
A novel approach to estimate the distribution, density and at-sea risks of a centrally-placed mobile marine vertebrate
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Formulating management strategies for mobile marine species is challenging, as knowledge is required of distribution, density, and overlap with putative threats. As a step towards assimilating knowledge, ecological niche models may identify likely suitable habitats for species, but lack the ability to enumerate species densities. Traditionally, this has been catered for by sightings-based distance sampling methods that may have practical and logistical limitations. Here we describe a novel method to estimate at-sea distribution and densities of a marine vertebrate, using historic aerial surveys of Gabonese leatherback turtle (Dermochelys coriacea) nesting beaches and satellite telemetry data of females at sea. We contextualise modelled patterns of distribution with putative threat layers of boat traffic, including fishing vessels and large ship movements, using Vessel Monitoring System (VMS) and Automatic Identification System (AIS) data. We identify key at-sea areas in which protection for inter-nesting leatherback turtles could be considered within the coastal zone of Gabonese Exclusive Economic Zone (EEZ). Our approach offers a holistic technique that merges multiple datasets and methodologies to build a deeper and insightful knowledge base with which to manage known activities at sea. As such, the methodologies presented in this study could be applied to other species of sea turtles for cumulative assessments; and with adaptation, may have utility in defining critical habitats for other central-place foragers such as pinnipeds, or sea bird species. Although our analysis focuses on a single species, we suggest that putative threats identified within this study (fisheries, seismic activity, general shipping) likely apply to other mobile marine vertebrates of conservation concern within Gabonese and central African coastal waters, such as olive ridley sea turtles (Lepidochelys olivacea), humpback dolphins (Sousa teuszii) and humpback whales (Megaptera novaeangliae).We thank the following for support and funding: CARPE (Central African Regional Program for the Environment, Darwin Initiative, EAZA ShellShock Campaign, Gabon Sea Turtle Partnership with funding from the Marine Turtle Conservation Fund (United States Fish and Wildlife Service, U.S. Department of the Interior), Harvest Energy, Large Pelagics Research Centre at the University of Massachusetts (Boston), NERC, Vaalco Energy and the Wildlife Conservation Society. We are sincerely grateful to the field teams and logistics staff who assisted in the aerial and ground surveys and with field-site assistance. BJG and MJW receive funding from the Natural Environment Research Council (NE/J012319/1), the European Union and the Darwin Initiative
Effects of the Insemination of Hydrogen Peroxide-Treated Epididymal Mouse Spermatozoa on γH2AX Repair and Embryo Development
BACKGROUND: Cryopreservation of human semen for assisted reproduction is complicated by cryodamage to spermatozoa caused by excessive reactive oxygen species (ROS) generation. METHODS AND FINDINGS: We used exogenous ROS (H(2)O(2)) to simulate cryopreservation and examined DNA damage repair in embryos fertilized with sperm with H(2)O(2)-induced DNA damage. Sperm samples were collected from epididymis of adult male KM mice and treated with capacitation medium (containing 0, 0.1, 0.5 and 1 mM H(2)O(2)) or cryopreservation. The model of DNA-damaged sperm was based on sperm motility, viability and the expression of γH2AX, the DNA damage-repair marker. We examined fertility rate, development, cell cleavage, and γH2AX level in embryos fertilized with DNA-damaged sperm. Cryopreservation and 1-mM H(2)O(2) treatment produced similar DNA damage. Most of the one- and two-cell embryos fertilized with DNA-damaged sperm showed a delay in cleavage before the blastocyst stage. Immunocytochemistry revealed γH2AX in the one- and four-cell embryos. CONCLUSIONS: γH2AX may be involved in repair of preimplantation embryos fertilized with oxygen-stressed spermatozoa
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
BACKGROUND: Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy. METHODS: RESTART was a prospective, randomised, open-label, blinded-endpoint, parallel-group trial at 122 hospitals in the UK that assessed whether starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. For this prespecified subgroup analysis, consultant neuroradiologists masked to treatment allocation reviewed brain CT or MRI scans performed before randomisation to confirm participant eligibility and rate features of the intracerebral haemorrhage and surrounding brain. We followed participants for primary (recurrent symptomatic intracerebral haemorrhage) and secondary (ischaemic stroke) outcomes for up to 5 years (reported elsewhere). For this report, we analysed eligible participants with intracerebral haemorrhage according to their treatment allocation in primary subgroup analyses of cerebral microbleeds on MRI and in exploratory subgroup analyses of other features on CT or MRI. The trial is registered with the ISRCTN registry, number ISRCTN71907627. FINDINGS: Between May 22, 2013, and May 31, 2018, 537 participants were enrolled, of whom 525 (98%) had intracerebral haemorrhage: 507 (97%) were diagnosed on CT (252 assigned to start antiplatelet therapy and 255 assigned to avoid antiplatelet therapy, of whom one withdrew and was not analysed) and 254 (48%) underwent the required brain MRI protocol (122 in the start antiplatelet therapy group and 132 in the avoid antiplatelet therapy group). There were no clinically or statistically significant hazards of antiplatelet therapy on recurrent intracerebral haemorrhage in primary subgroup analyses of cerebral microbleed presence (2 or more) versus absence (0 or 1) (adjusted hazard ratio [HR] 0·30 [95% CI 0·08-1·13] vs 0·77 [0·13-4·61]; pinteraction=0·41), cerebral microbleed number 0-1 versus 2-4 versus 5 or more (HR 0·77 [0·13-4·62] vs 0·32 [0·03-3·66] vs 0·33 [0·07-1·60]; pinteraction=0·75), or cerebral microbleed strictly lobar versus other location (HR 0·52 [0·004-6·79] vs 0·37 [0·09-1·28]; pinteraction=0·85). There was no evidence of heterogeneity in the effects of antiplatelet therapy in any exploratory subgroup analyses (all pinteraction>0·05). INTERPRETATION: Our findings exclude all but a very modest harmful effect of antiplatelet therapy on recurrent intracerebral haemorrhage in the presence of cerebral microbleeds. Further randomised trials are needed to replicate these findings and investigate them with greater precision. FUNDING: British Heart Foundation
Impact of treatment policies on patient outcomes and resource utilization in acute cholecystitis in Japanese hospitals
BACKGROUND: Although currently available evidence predominantly recommends early laparoscopic cholecystectomy (LC) for the treatment of acute cholecystitis, this strategy has not been widely adopted in Japan. Herein, we describe a hospital-based study of patients with acute cholecystitis in 9 Japanese teaching hospitals in order to evaluate the impact of different institutional strategies in treating acute cholecystitis on overall patient outcomes and medical resource utilization. METHODS: From an administrative database and chart review, we identified 228 patients diagnosed with acute cholecystitis who underwent cholecystectomy between April 2001 and June 2003. In order to examine the relationship between hospitals' propensity to perform LC and patient outcomes and/or medical resource utilization, we divided the hospitals into three groups according to the observed to expected ratio of performing LC (LC propensity), and compared the postoperative complication rate, length of hospitalization (LOS), and medical charges. RESULTS: No hospital adopted the policy of early surgery, and the mean overall LOS among the subjects was 30.9 days. The use of laparoscopic surgery varied widely across the hospitals; the adjusted rates of LC to total cholecystectomies ranged from 9.5% to 77%. Although intra-operative complication rate was significantly higher among patients whom LC was initially attempted when compared to those whom OC was initially attempted (9.7% vs. 0%), there was no significant association between LC propensity and postoperative complication rates. Although the postoperative time to oral intake and postoperative LOS was significantly shorter in hospitals with high use of LC, the overall LOS did not differ among hospital groups with different LC propensities. Medical charges were not associated with LC propensity. CONCLUSION: Under the prevailing policy of delayed surgery, in terms of the postoperative complication rate and medical resource utilization, our study did not show the superiority of LC in treating acute cholecystitis patients. The timing of surgery and discharge was mainly determined by the institutional policy in Japan, rather than by the clinical course of the patient; however, considering the substantially less postoperative pain and shorter recovery time of LC compared to OC, LC should be actively applied for the treatment of acute cholecystitis. If the policy of early surgery were universally applied, the advantage of LC over OC may be more clearly demonstrated
Expression of ADAMTS-8, a secreted protease with antiangiogenic properties, is downregulated in brain tumours
Angiogenesis and extracellular matrix degradation are key events in tumour progression, and factors regulating stromal–epithelial interactions and matrix composition are potential targets for the development of novel anti-invasive/antiangiogenic therapies. Here, we examine the expression of ADAMTS-8, a secreted protease with antiangiogenic properties, in brain tissues. Using quantitative RT–polymerase chain reaction (PCR), high, equivalent expression of ADAMTS-8 was found in normal whole brain, cerebral cortex, frontal lobe, cerebellum and meninges. ADAMTS-8 expression in 34 brain tumours (including 22 high-grade gliomas) and four glioma cell lines indicated at least two-fold reduction in mRNA compared to normal whole brain in all neoplastic tissues, and no detectable expression in 14 out of 34 (41%) tumours or four out of four (100%) cell lines. In contrast, differential expression of TSP1 and VEGF was seen in nine out of 15 (60%) and seven out of 13 (54%) tumours, with no relationship in the expression of these genes. Immunohistochemistry and Western analysis indicated downregulation of ADAMTS-8 protein in >77% tumours. Methylation-specific PCR analysis of ADAMTS-8 indicated promoter hypermethylation in one out of 24 brain tumours (a metastasis) and three out of four glioma cell lines suggesting an alternative mechanism of downregulation. These data suggest a role for ADAMTS-8 in brain tumorigenesis, warranting further investigation into its role in regulation of tumour angiogenesis and local invasion
Informing Marine Protected Area Designation and Management for Nesting Olive Ridley Sea Turtles Using Satellite Tracking
This is the final version. Available from Frontiers Media via the DOI in this record. Understanding the horizontal and vertical habitat of olive ridley sea turtles (Lepidochelys olivacea), a threatened species, is critical for determining regions for protection and relevant gear modifications that may effectively reduce bycatch, the largest threat to this species. Satellite transmitters were used to determine the movement and dive behavior of 21 female olive ridley turtles tagged in Pongara National Park, Gabon during the 2012, 2013, and 2015 nesting seasons. A switching state-space model was used to filter the tracking data and categorize the internesting and post-nesting movements. Gridded utilization distribution (UD) home range analysis of tracking data revealed that the entire core habitat occurred in the Komo Estuary during the internesting period. Within the Komo Estuary, 58% of this core UD occurred in shipping lanes. Dive data from the 2015 tagging season revealed that during the internesting period, turtles spent the majority of their time resting on the estuary seabed. Approximately 20% of all dive time was spent on the bottom and all maximum dive depths corresponded to the depth of the seabed, indicating that bottom set gear during the internesting period may pose the greatest potential for fisheries interactions. National parks currently protect many of the nesting sites and the Gabon Bleu initiative has formally designated 10 new marine parks and a network of community and industrial fishing zones; this data was a layer used in determining the park and zone boundaries. Shared use of the estuary by fisheries, shipping, and olive ridley turtles creates a need for management measures to reduce interactions. Thus, the results from this study can further provide detailed information that can be used to support the development of evidence-based management plans
Cerebral blood volume, genotype and chemosensitivity in oligodendroglial tumours
INTRODUCTION: The biological factors responsible for differential chemoresponsiveness in oligodendroglial tumours with or without the −1p/−19q genotype are unknown, but tumour vascularity may contribute. We aimed to determine whether dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) could distinguish molecular subtypes of oligodendroglial tumour, and examined the relationship between relative cerebral blood volume (rCBV) and outcome following procarbazine, lomustine and vincristine (PCV) chemotherapy. METHODS: Pretherapy rCBV was calculated and inter- and intraobserver variability assessed. Allelic imbalance in 1p36, 19q13, 17p13, 10p12–15, and 10q22–26 and p53 mutation (exons 5–8) were determined. rCBV was compared with genotype and clinicopathological characteristics (n=37) and outcome following PCV chemotherapy (n=33). RESULTS: 1p/19q loss was seen in 6/9 grade II oligodendrogliomas, 6/14 grade II oligoastrocytomas, 4/4 grade III oligodendrogliomas, and 3/10 grade III oligoastrocytomas. rCBV measurements had good inter- and intraobserver variability, but did not distinguish histology subtype or grade. Tumours with 1p/19q loss had higher rCBV values (Student’s t-test P=0.001). Receiver operating characteristic analysis revealed a cut-off of 1.59 for identifying genotype (sensitivity 92%, specificity 76%). Tumours with high and low rCBV showed response to chemotherapy. The −1p/−19q genotype, but not rCBV, was strongly associated with response, progression-free and overall survival following PCV chemotherapy. Tumours with high rCBV and intact 1p/19q were associated with shorter progression-free and overall patient survival than those with intact 1p/19q and low rCBV or high rCBV and 1p/19q loss. CONCLUSION: rCBV identifies oligodendroglial tumours with 1p/19q loss, but does not predict chemosensitivity. The prognostic significance of rCBV may differ in oligodendroglial tumours with or without the −1p/−19q genotype
Targeting neonatal ischemic brain injury with a pentapeptide-based irreversible caspase inhibitor
Brain protection of the newborn remains a challenging priority and represents a totally unmet medical need. Pharmacological inhibition of caspases appears as a promising strategy for neuroprotection. In a translational perspective, we have developed a pentapeptide-based group II caspase inhibitor, TRP601/ORPHA133563, which reaches the brain, and inhibits caspases activation, mitochondrial release of cytochrome c, and apoptosis in vivo. Single administration of TRP601 protects newborn rodent brain against excitotoxicity, hypoxia–ischemia, and perinatal arterial stroke with a 6-h therapeutic time window, and has no adverse effects on physiological parameters. Safety pharmacology investigations, and toxicology studies in rodent and canine neonates, suggest that TRP601 is a lead compound for further drug development to treat ischemic brain damage in human newborns
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