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1.
Nature ; 625(7996): 760-767, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38092039

ABSTRACT

GDF15, a hormone acting on the brainstem, has been implicated in the nausea and vomiting of pregnancy, including its most severe form, hyperemesis gravidarum (HG), but a full mechanistic understanding is lacking1-4. Here we report that fetal production of GDF15 and maternal sensitivity to it both contribute substantially to the risk of HG. We confirmed that higher GDF15 levels in maternal blood are associated with vomiting in pregnancy and HG. Using mass spectrometry to detect a naturally labelled GDF15 variant, we demonstrate that the vast majority of GDF15 in the maternal plasma is derived from the feto-placental unit. By studying carriers of rare and common genetic variants, we found that low levels of GDF15 in the non-pregnant state increase the risk of developing HG. Conversely, women with ß-thalassaemia, a condition in which GDF15 levels are chronically high5, report very low levels of nausea and vomiting of pregnancy. In mice, the acute food intake response to a bolus of GDF15 is influenced bi-directionally by prior levels of circulating GDF15 in a manner suggesting that this system is susceptible to desensitization. Our findings support a putative causal role for fetally derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by prepregnancy exposure to the hormone, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.


Subject(s)
Growth Differentiation Factor 15 , Hyperemesis Gravidarum , Nausea , Vomiting , Animals , Female , Humans , Mice , Pregnancy , beta-Thalassemia/blood , beta-Thalassemia/metabolism , Fetus/metabolism , Growth Differentiation Factor 15/blood , Growth Differentiation Factor 15/metabolism , Hormones/blood , Hormones/metabolism , Hyperemesis Gravidarum/complications , Hyperemesis Gravidarum/metabolism , Hyperemesis Gravidarum/prevention & control , Hyperemesis Gravidarum/therapy , Nausea/blood , Nausea/complications , Nausea/metabolism , Placenta/metabolism , Vomiting/blood , Vomiting/complications , Vomiting/metabolism
2.
Rev Sci Tech ; 42: 173-179, 2023 05.
Article in English | MEDLINE | ID: mdl-37232307

ABSTRACT

With modelling becoming increasingly important in helping to inform decisions about animal diseases, it is essential that the process be optimised to gain the maximum benefit for the decision-maker. Here, the authors set out ten steps that can improve this process for all concerned. Four steps describe initialisation to ensure that the question, answer and timescale are defined; two steps describe the modelling process and quality assurance; and four steps describe the reporting stage. The authors believe that this greater emphasis at the beginning and end of a modelling project will increase the relevance of the work and understanding of the results, and thus contribute towards better decision-making.


Compte tenu de l'importance croissante de la modélisation pour documenter les décisions sur les maladies animales, il est essentiel d'optimiser le processus afin de le rendre le plus profitable possible pour les personnes décisionnaires. Les auteurs définissent dix étapes permettant d'améliorer le processus pour tous les intervenants. Quatre étapes concernent la phase de démarrage et visent à s'assurer que les questions posées, les réponses obtenues et le calendrier sont bien définis ; les deux étapes suivantes portent sur le processus de modélisation et sur l'assurance qualité ; les quatre dernières décrivent la phase d'élaboration des rapports. Les auteurs estiment que cette attention particulière accordée aux phases de démarrage et d'achèvement d'un projet de modélisation rend l'exercice plus pertinent et améliore la compréhension des résultats, ce qui contribue à une meilleure prise de décisions.


Dada la creciente importancia que está cobrando la modelización como herramienta para ayudar a fundamentar las decisiones relativas a enfermedades animales, es esencial optimizar el proceso para que las instancias decisorias puedan aprovecharlo al máximo. Los autores exponen diez pasos que pueden mejorar el proceso para cuantos trabajan en este ámbito. En cuatro pasos se describe la inicialización, que sirve para definir debidamente la pregunta, la respuesta y la escala temporal de que se trate. En otros dos pasos se describe el proceso de modelización y de garantía de calidad, mientras que en los últimos cuatro pasos se describe la fase de producción de informes. Los autores consideran que el hecho de otorgar mayor peso a las fases iniciales y finales de un proyecto de modelización hará que el trabajo gane en pertinencia y que se entiendan mejor sus resultados, lo que a su vez contribuye a un proceso más eficaz de adopción de decisiones.


Subject(s)
Communicable Diseases , Animals , Communicable Diseases/epidemiology , Communicable Diseases/veterinary , Health Policy
3.
Ultrasound Obstet Gynecol ; 59(2): 209-219, 2022 02.
Article in English | MEDLINE | ID: mdl-34405928

ABSTRACT

OBJECTIVE: Stillbirth is a potentially preventable complication of pregnancy. Identifying women at high risk of stillbirth can guide decisions on the need for closer surveillance and timing of delivery in order to prevent fetal death. Prognostic models have been developed to predict the risk of stillbirth, but none has yet been validated externally. In this study, we externally validated published prediction models for stillbirth using individual participant data (IPD) meta-analysis to assess their predictive performance. METHODS: MEDLINE, EMBASE, DH-DATA and AMED databases were searched from inception to December 2020 to identify studies reporting stillbirth prediction models. Studies that developed or updated prediction models for stillbirth for use at any time during pregnancy were included. IPD from cohorts within the International Prediction of Pregnancy Complications (IPPIC) Network were used to validate externally the identified prediction models whose individual variables were available in the IPD. The risk of bias of the models and cohorts was assessed using the Prediction study Risk Of Bias ASsessment Tool (PROBAST). The discriminative performance of the models was evaluated using the C-statistic, and calibration was assessed using calibration plots, calibration slope and calibration-in-the-large. Performance measures were estimated separately in each cohort, as well as summarized across cohorts using random-effects meta-analysis. Clinical utility was assessed using net benefit. RESULTS: Seventeen studies reporting the development of 40 prognostic models for stillbirth were identified. None of the models had been previously validated externally, and the full model equation was reported for only one-fifth (20%, 8/40) of the models. External validation was possible for three of these models, using IPD from 19 cohorts (491 201 pregnant women) within the IPPIC Network database. Based on evaluation of the model development studies, all three models had an overall high risk of bias, according to PROBAST. In the IPD meta-analysis, the models had summary C-statistics ranging from 0.53 to 0.65 and summary calibration slopes ranging from 0.40 to 0.88, with risk predictions that were generally too extreme compared with the observed risks. The models had little to no clinical utility, as assessed by net benefit. However, there remained uncertainty in the performance of some models due to small available sample sizes. CONCLUSIONS: The three validated stillbirth prediction models showed generally poor and uncertain predictive performance in new data, with limited evidence to support their clinical application. The findings suggest methodological shortcomings in their development, including overfitting. Further research is needed to further validate these and other models, identify stronger prognostic factors and develop more robust prediction models. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.


Subject(s)
Perinatal Death/prevention & control , Pregnancy Complications/diagnosis , Stillbirth , Cohort Studies , Female , Fetal Development/physiology , Humans , Infant, Newborn , Models, Statistical , Pregnancy , Prognosis , Regression Analysis , Risk Assessment , Ultrasonography, Prenatal
4.
One Health Outlook ; 3: 7, 2021.
Article in English | MEDLINE | ID: mdl-33834160

ABSTRACT

The novel coronavirus SARS-CoV-2 likely emerged from a wildlife source with transmission to humans followed by rapid geographic spread throughout the globe and severe impacts on both human health and the global economy. Since the onset of the pandemic, there have been many instances of human-to-animal transmission involving companion, farmed and zoo animals, and limited evidence for spread into free-living wildlife. The establishment of reservoirs of infection in wild animals would create significant challenges to infection control in humans and could pose a threat to the welfare and conservation status of wildlife. We discuss the potential for exposure, onward transmission and persistence of SARS-CoV-2 in an initial selection of wild mammals (bats, canids, felids, mustelids, great apes, rodents and cervids). Dynamic risk assessment and targeted surveillance are important tools for the early detection of infection in wildlife, and here we describe a framework for collating and synthesising emerging information to inform targeted surveillance for SARS-CoV-2 in wildlife. Surveillance efforts should be integrated with information from public and veterinary health initiatives to provide insights into the potential role of wild mammals in the epidemiology of SARS-CoV-2.

6.
QJM ; 114(3): 159-162, 2021 05 19.
Article in English | MEDLINE | ID: mdl-33245119

Subject(s)
Videoconferencing , Humans
7.
Sci Rep ; 10(1): 22259, 2020 12 17.
Article in English | MEDLINE | ID: mdl-33335122

ABSTRACT

Abnormal maternal serum biomarkers (AMSB), identified through the aneuploidy screening programme, are frequent incidental findings in pregnancy. They are associated with fetal growth restriction (FGR), but previous studies have not examined whether this association is with early-onset (< 34 weeks) or late-onset (> 34 weeks) FGR; as a result there is no consensus on management. The aims of this study were to determine the prevalence and phenotype of FGR in women with AMSB and test the predictive value of placental sonographic screening to predict early-onset FGR. 1196 pregnant women with AMSB underwent a 21-24 week "placental screen" comprising fetal and placental size, and uterine artery Doppler. Multivariable regression was used to calculate a predictive model for early-onset FGR (birthweight centile < 3rd/< 10th with absent umbilical end-diastolic flow, < 34 weeks). FGR prevalence was high (10.3%), however early-onset FGR was uncommon (2.3%). Placental screening effectively identified early-onset (area under the curve (AUC) 0.93, 95% confidence interval (CI) 0.87-1.00), but not late-onset FGR (AUC 0.70, 95% CI 0.64-0.75). Internal validation demonstrated robust performance for detection/exclusion of early-onset FGR. In this cohort, utilisation of our proposed algorithm with targeted fetal growth and Doppler surveillance, compared with universal comprehensive surveillance would have avoided 1044 scans, potentiating significant cost-saving for maternity services.


Subject(s)
Biomarkers/blood , Fetal Growth Retardation/blood , Infant, Small for Gestational Age/blood , Placenta/diagnostic imaging , Adult , Area Under Curve , Female , Fetal Growth Retardation/physiopathology , Gestational Age , Humans , Infant, Newborn , Placenta/pathology , Predictive Value of Tests , Pregnancy , Retrospective Studies , Risk Assessment , Ultrasonography, Doppler , Ultrasonography, Prenatal/methods , Uterine Artery/diagnostic imaging , Uterine Artery/pathology
9.
Ultrasound Obstet Gynecol ; 55(5): 599-604, 2020 05.
Article in English | MEDLINE | ID: mdl-32266750

ABSTRACT

OBJECTIVE: Use of the Growth Assessment Protocol (GAP) has increased internationally under the assumption that it reduces the stillbirth rate. The evidence for this is limited and based largely on an ecological time-trend study. Discordance in the uptake of the GAP program between Scotland and England/Wales enabled us to assess the assertion that implementation of GAP leads to a reduced stillbirth rate. METHODS: We analyzed data from the National Records for Scotland and the Office for National Statistics on the number of singleton maternities and stillbirths in Scotland and in England and Wales, respectively, from 1 January 2000 to 31 December 2015. National uptake of the GAP program over time in each of the regions was recorded. Stillbirth rate per 1000 maternities was calculated, according to year of delivery, and compared between Scotland and England/Wales. RESULTS: During the study period, there were 870 632 singleton maternities in Scotland, of which 4243 were stillbirths, and there were 10 469 120 singleton maternities in England and Wales, of which 51 562 were stillbirths. There was a marked difference in uptake of the GAP program between the two regions, with substantially fewer maternity units in Scotland implementing the program. Stillbirth rates were static up to 2010, with a decline thereafter in both regions, to 3.75 (95% CI, 3.25-4.30) per 1000 maternities in Scotland and 4.30 (95% CI, 4.15-4.46) per 1000 maternities in England and Wales in 2015. From 2010 onwards, the decline in Scotland was faster, equating to 48 (95% CI, 47.9-48.1) fewer stillbirths per 100 000 maternities in Scotland than in England and Wales from 2010 to 2015 compared with 2000 to 2009. CONCLUSIONS: We observed a decline in stillbirth rate in England and Wales, which coincided with implementation of the GAP program. However, a concurrent decline in stillbirth rate was observed in Scotland in the absence of increased implementation of GAP. The secular rates of change in stillbirth rate in England and Wales cannot be used to infer efficacy of the GAP program. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.


Subject(s)
Fetal Growth Retardation/diagnosis , Prenatal Diagnosis/statistics & numerical data , Risk Assessment/statistics & numerical data , Stillbirth/epidemiology , England/epidemiology , Female , Fetal Development , Health Plan Implementation , Humans , Pregnancy , Prenatal Diagnosis/methods , Prenatal Diagnosis/standards , Program Evaluation , Risk Assessment/methods , Risk Assessment/standards , Scotland/epidemiology , United Kingdom/epidemiology , Wales/epidemiology
11.
Nanoscale ; 11(12): 5771, 2019 03 21.
Article in English | MEDLINE | ID: mdl-30855062

ABSTRACT

Correction for 'High performing AgNW transparent conducting electrodes with a sheet resistance of 2.5 Ω Sq-1 based upon a roll-to-roll compatible post-processing technique' by D. Kumar et al., Nanoscale, 2019, DOI: 10.1039/c8nr07974a.

12.
Nanoscale ; 11(12): 5760-5769, 2019 Mar 21.
Article in English | MEDLINE | ID: mdl-30775736

ABSTRACT

A report of transparent and conducting silver nanowires (AgNWs) that produce remarkable electrical performance, surface planarity and environmental stability is given. This research presents an innovative process that relies on three sequential steps, which are roll-to-roll (R2R) compatible: thermal embossing, infrared sintering and plasma treatment. This process leads to the demonstration of a conductive film with a sheet resistance of 2.5 Ω sq-1 and high transmittance, thus demonstrating the highest reported figure-of-merit in AgNWs to date (FoM = 933). A further benefit of the process is that the surface roughness is substantially reduced compared to traditional AgNW processing techniques. The consideration of the long-term stability is given by developing an accelerated life test process that simultaneously stresses the applied bias and temperature. Regression line fitting shows that a ∼150-times improvement in stability is achieved under 'normal operational conditions' when compared to traditionally deposited AgNW films. X-ray photoelectron spectroscopy (XPS) is used to understand the root cause of the improvement in long-term stability, which is related to reduced chemical changes in the AgNWs.

13.
J Inorg Biochem ; 191: 94-111, 2019 02.
Article in English | MEDLINE | ID: mdl-30476714

ABSTRACT

Curcumin is a natural product with a broad spectrum of beneficial properties relating to pharmaceutical applications, extending from traditional remedies to modern cosmetics. The biological activity of such pigments, however, is limited by their solubility and bioavailability, thereby necessitating new ways of achieving optimal tissue cellular response and efficacy as drugs. Metal ion complexation provides a significant route toward improvement of curcumin stability and biological activity, with vanadium being a representative such metal ion, amply encountered in biological systems and exhibiting exogenous bioactivity through potential pharmaceuticals. Driven by the need to optimally increase curcumin bioavailability and bioactivity through complexation, synthetic efforts were launched to seek out stable species, ultimately leading to the synthesis and isolation of a new ternary V(IV)-curcumin-(2,2'-bipyridine) complex. Physicochemical characterization (elemental analysis, FT-IR, Thermogravimetry (TGA), UV-Visible, NMR, ESI-MS, Fluorescence, X-rays) portrayed the solid-state and solution properties of the ternary complex. Pulsed-EPR spectroscopy, in frozen solutions, suggested the presence of two species, cis- and trans-conformers. Density Functional Theory (DFT) calculations revealed the salient features and energetics of the two conformers, thereby complementing EPR spectroscopy. The well-described profile of the vanadium species led to its in vitro biological investigation involving toxicity, cell metabolism inhibition in S. cerevisiae cultures, Reactive Oxygen Species (ROS)-suppressing capacity, lipid peroxidation, and plasmid DNA degradation. A multitude of bio-assays and methodologies, in comparison to free curcumin, showed that it exhibits its antioxidant potential in a concentration-dependent fashion, thereby formulating a bioreactivity profile supporting development of new efficient vanado-pharmaceuticals, targeting (extra)intra-cellular processes under (patho)physiological conditions.


Subject(s)
Antioxidants/chemistry , Antioxidants/pharmacology , Curcumin/chemistry , Curcumin/pharmacology , Antioxidants/chemical synthesis , Crystallography, X-Ray , Curcumin/chemical synthesis , In Vitro Techniques , Reactive Oxygen Species/metabolism , Spectrum Analysis/methods
14.
Ultrasound Obstet Gynecol ; 52(1): 78-86, 2018 07.
Article in English | MEDLINE | ID: mdl-28452133

ABSTRACT

OBJECTIVES: To compare the association between risk of emergency Cesarean delivery (CD) and non-customized vs customized ultrasound estimated fetal weight (EFW) at 36 weeks' gestation, determine whether addition of ultrasound EFW to a model based on maternal characteristics alone improved prediction of emergency CD, assess the screening performance of a multivariable model using both EFW and maternal characteristics to predict emergency CD, and determine whether women at high predicted risk of emergency CD based on this model had higher risk of maternal and perinatal morbidity compared with screen-negative women. METHODS: We studied 3047 low-risk (no pre-existing medical conditions or acquired complications of pregnancy) nulliparous women from the prospective Pregnancy Outcome Prediction study (Cambridge, UK) cohort, who underwent ultrasound EFW at ∼36 weeks' gestation. Both the women and their clinicians were blinded to fetal biometry results. Emergency CD was defined as delivery by Cesarean section in pregnancies in which the date of delivery had not been prearranged. Additional candidate predictors of emergency CD evaluated were maternal age, height, body mass index (BMI), weight gain, fetal abdominal circumference growth velocity and fetal sex. External validation of the predictive model was performed using routinely collected data from 55 337 births in Scotland between 2003 and 2008. Women with an estimated risk of emergency CD ≥ 40% were defined as screen positive. RESULTS: Blinded EFW was associated strongly with the risk of emergency CD (coefficient for increase of 1 SD in EFW, 0.39 (95% CI, 0.30-0.48); odds ratio (OR), 1.48 (95% CI, 1.35-1.62)). The coefficient for customized EFW was similar (0.42 (95% CI, 0.33-0.51); OR, 1.53 (95% CI, 1.39-1.67)); hence, for simplicity, non-customized EFW was employed subsequently. A multivariable logistic regression model combining maternal characteristics (age, height, BMI and weight gain between 12 and 36 weeks) was moderately predictive of emergency CD (area under the receiver-operating characteristics curve (AUC) = 0.68). Addition of blinded EFW to the model increased the AUC to 0.71 and improved prediction (likelihood-ratio test P < 0.0001). Based on this model, 189 (6.2%) women were screen positive and 48% of these delivered by CD. Screen-positive women had elevated risks of severe postpartum hemorrhage (relative risk (RR), 2.49; 95% CI, 1.83-3.38), any adverse neonatal outcome (RR, 1.86; 95% CI, 1.22-2.82) and severe adverse neonatal outcome (RR, 4.03; 95% CI, 1.35-12.03) compared with screen-negative women. The risks of these events were also higher compared with women who had a term CD for breech presentation. The model was similarly predictive of the risk of emergency CD and perinatal morbidity when evaluated using the dataset from Scotland. CONCLUSIONS: Ultrasound EFW at 36 weeks, combined with maternal characteristics, can identify women who are at increased risk of subsequent emergency CD. These women are at increased risk of maternal and perinatal morbidity compared with women at low risk of emergency CD and those having CD for breech presentation at term. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.


Subject(s)
Biometry , Cesarean Section/statistics & numerical data , Fetal Growth Retardation/diagnostic imaging , Fetal Weight/physiology , Labor, Induced/statistics & numerical data , Ultrasonography, Prenatal , Adult , Double-Blind Method , Female , Fetal Growth Retardation/physiopathology , Gestational Age , Humans , Infant, Newborn , Infant, Small for Gestational Age , Parity , Predictive Value of Tests , Pregnancy , Pregnancy Outcome , Pregnancy Trimester, Third , Prospective Studies , ROC Curve , Risk Assessment
15.
Ultrasound Obstet Gynecol ; 51(6): 783-791, 2018 Jun.
Article in English | MEDLINE | ID: mdl-28425156

ABSTRACT

OBJECTIVES: To compare the diagnostic effectiveness of selective vs universal ultrasonography as a screening test for large-for-gestational-age (LGA) infants, and to determine whether previously described ultrasound markers of excessive fetal growth could identify suspected LGA fetuses that are at increased risk of adverse neonatal outcome. METHODS: Data from the Pregnancy Outcome Prediction study, a prospective cohort study of nulliparous women with a viable singleton pregnancy at the time of the dating ultrasound scan, were analyzed. Women were selected for clinically indicated ultrasound assessment in the third trimester as per routine clinical care, and the results of these scans were reported ('selective ultrasonography'). In addition, all participants underwent research ultrasound scans, including estimated fetal weight (EFW) assessment, at around 36 weeks' gestation, in which both the women and their clinicians were blinded to the results ('universal ultrasonography'). Participants who attended the 36-week research scan and had a live birth at the Rosie Hospital were included in the study. Screen positive for LGA was defined as EFW > 90th percentile at ≥ 34 weeks. RESULTS: The current analysis included 3866 eligible women, of whom 1354 (35%) had a clinically indicated ultrasound scan at or after 34 weeks' gestation. A total of 177 (4.6%) infants had a birth weight > 90th percentile. The sensitivity for detection of LGA infants was 27% for selective ultrasonography and 38% for universal ultrasonography. The specificity of both approaches was high (99% and 97%, respectively). Using universal ultrasonography, neonatal outcome differed (P for interaction) by abdominal circumference growth velocity (ACGV) for both any neonatal morbidity (P = 0.08) and severe adverse neonatal outcome (P = 0.03). LGA fetuses with increased ACGV had a relative risk of any neonatal morbidity of 2.0 (95% CI, 1.1-3.6; P = 0.04) and of severe adverse neonatal outcome of 6.5 (95% CI, 2.0-21.1; P = 0.01), whereas LGA fetuses with normal ACGV were not at increased risk. CONCLUSIONS: Third-trimester screening of nulliparous women by universal ultrasound fetal biometry increases the detection rate of LGA infants and, combined with ACGV, identifies those at increased risk of adverse neonatal outcome. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.


Subject(s)
Fetal Macrosomia/diagnosis , Ultrasonography, Prenatal , Adult , Cohort Studies , Decision Support Techniques , England , Female , Fetal Macrosomia/diagnostic imaging , Fetal Macrosomia/mortality , Humans , Infant, Newborn , Predictive Value of Tests , Pregnancy , Pregnancy Outcome , Pregnancy Trimesters , Prospective Studies , Sensitivity and Specificity , Young Adult
16.
Rev Sci Tech ; 37(2): 551-557, 2018 Aug.
Article in English | MEDLINE | ID: mdl-30747126

ABSTRACT

Rabies is probably the most commonly modelled disease as both its epidemiology and host dynamics are well understood. Models are simplifications of reality and there are different approaches to achieving these representations. Over time, modelling has moved from simple mathematical methods towards more realistic biological models that incorporate spatial and individual variation. In this article, the author reviews models that have increased our understanding of actions taken to manage disease. The most developed of these focus on fox (Vulpes vulpes) rabies in Europe, where a suite of models has helped researchers to explore fox management options and the complications caused by other potential hosts, such as raccoon dogs (Nyctereutes procyonoides). Models of dog (Canis familiaris) rabies support the idea of a 70% vaccine threshold for disease elimination and are now being used to explore and optimise management methods, combining vaccination with either surgical sterilisation or the use of chemical sterilisation. Future challenges are also identified, such as the need to develop practical management models in other hosts, and to explore different Lyssavirus strains in bats.


La rage est probablement la maladie pour laquelle on recourt le plus souvent à des modèles, son épidémiologie et sa dynamique chez ses hôtes étant désormais bien connues. Les modèles sont des représentations simplifiées de la réalité que l'on peut obtenir de différentes manières. Au fil du temps, la modélisation a évolué depuis les premières méthodes mathématiques simples jusqu'aux modèles biologiques actuels, plus réalistes et capables d'intégrer des variations spatiales et individuelles. L'auteur passe en revue les modèles qui ont permis de mieux comprendre les mesures à adopter pour maîtriser la maladie. Les plus sophistiqués de ces modèles portent sur la rage chez le renard (Vulpes vulpes) en Europe, où une suite de modèles a permis aux chercheurs d'étudier diverses options en matière de gestion des renards, ainsi que les complications induites par la présence d'autres hôtes potentiels, en particulier le chien viverrin (Nyctereutes procyonoides). Les modèles portant sur la rage chez le chien (Canis familiaris) confortent l'idée d'un seuil de 70 % de couverture vaccinale pour l'élimination de la maladie et sont utilisés actuellement pour étudier et optimiser les méthodes de gestion qui associent à la vaccination canine une stérilisation chirurgicale ou chimique. Les défis à venir sont également mis en lumière, par exemple la nécessité de mettre au point des modèles de gestion applicables chez d'autres hôtes et d'étudier les différentes souches de Lyssavirus chez les chauves-souris.


La rabia es probablemente la enfermedad de la que más a menudo se elaboran modelos, pues se conocen bien tanto su epidemiología como su dinámica en los anfitriones. Para construir modelos, que son simplificaciones de la realidad, cabe aplicar distintas lógicas. Con el transcurrir del tiempo, los primeros modelos, que eran sencillos métodos matemáticos, han dado paso a modelos biológicos más cercanos a la realidad, que incorporan las variaciones espaciales e individuales. El autor pasa revista a los modelos que nos han aportado un mejor conocimiento de las medidas adecuadas para combatir la enfermedad. De ellos, los más perfeccionados se refieren a la rabia del zorro (Vulpes vulpes) en Europa, donde los investigadores se han servido de un conjunto de modelos para estudiar distintas opciones de lucha en el zorro, así como las complicaciones ocasionadas por otros posibles anfitriones, como el perro mapache (Nyctereutes procyonoides). Los modelos de la rabia del perro (Canis familiaris) avalan la idea de que el umbral de vacunaciones para poder eliminar la enfermedad se sitúa en un 70%. Estos modelos se utilizan ahora para estudiar y optimizar los métodos de lucha, combinando la práctica de vacunaciones con procedimientos de esterilización quirúrgica o química. El autor también expone las dificultades que nos aguardan de cara el futuro, como la elaboración de modelos prácticos para combatir la enfermedad en otros anfitriones o el estudio de diferentes cepas de Lyssavirus en los murciélagos.


Subject(s)
Dog Diseases/prevention & control , Models, Biological , Rabies/veterinary , Animals , Animals, Wild , Dogs , Humans , Rabies/prevention & control
17.
Placenta ; 63: 45-52, 2018 03.
Article in English | MEDLINE | ID: mdl-29183631

ABSTRACT

INTRODUCTION: Birth weight to placenta weight (BWPW)-ratio is an indicator of the ability of the placenta to maintain adequate nutrient supply to the fetus. We sought to investigate the relationship between BWPW-ratio with fetal growth, utero-placental Doppler and neonatal and maternal morbidity. METHODS: We studied a group of 3311 women recruited to a prospective cohort study of nulliparous women (Rosie Hospital, Cambridge, UK) who delivered a live born infant at term and whose placental weight and birth weight were known. Ultrasonic indices and BWPW ratio were converted to gestational age adjusted z scores. Analysis of continuous variables was by multivariable linear regression. BWPW ratio was also categorized (lowest or highest quintile, both referent to quintiles 2 to 4) and associations with adverse outcomes analyzed using multivariable logistic regression. RESULTS: Lowest quintile of BWPW-ratio was associated (adjusted odds ratio [95% CI], P) with both neonatal morbidity (1.55 [1.12-2.14], 0.007) and maternal diabetes (1.75 [1.18-2.59], 0.005). Highest quintile of BWPW ratio was associated with a reduced risk of maternal obesity (0.71 [0.53 to 0.95], 0.02) and preeclampsia (0.51 [0.31 to 0.84], 0.008), but higher (adjusted z score [95% CI], P) uterine artery Doppler mean pulsatility index (PI) at 20 weeks of gestation (0.09 [0.01-0.18], 0.04) and umbilical artery Doppler PI at 36 weeks of gestation (0.16 [0.07-0.25], <0.001). CONCLUSION: BWPW-ratio is related to ultrasonic measurements and both neonatal and maternal morbidity. Therefore, this ratio may be an indicative marker of immediate and longer term health risks for an individual.


Subject(s)
Birth Weight/physiology , Parity/physiology , Placenta/anatomy & histology , Adult , Female , Humans , Organ Size/physiology , Placenta/diagnostic imaging , Pregnancy , Prospective Studies , Ultrasonography, Prenatal , Umbilical Arteries/diagnostic imaging , Uterine Artery/diagnostic imaging
18.
Epidemiol Infect ; 145(12): 2445-2457, 2017 09.
Article in English | MEDLINE | ID: mdl-28737119

ABSTRACT

Passive surveillance for lyssaviruses in UK bats has been ongoing since 1987 and has identified 13 cases of EBLV-2 from a single species; Myotis daubentonii. No other lyssavirus species has been detected. Between 2005 and 2015, 10 656 bats were submitted, representing 18 species, creating a spatially and temporally uneven sample of British bat fauna. Uniquely, three UK cases originate from a roost at Stokesay Castle in Shropshire, England, where daily checks for grounded and dead bats are undertaken and bat carcasses have been submitted for testing since 2007. Twenty per cent of Daubenton's bats submitted from Stokesay Castle since surveillance began, have tested positive for EBLV-2. Phylogenetic analysis reveals geographical clustering of UK viruses. Isolates from Stokesay Castle are more closely related to one another than to viruses from other regions. Daubenton's bats from Stokesay Castle represent a unique opportunity to study a natural population that appears to maintain EBLV-2 infection and may represent endemic infection at this site. Although the risk to public health from EBLV-2 is low, consequences of infection are severe and effective communication on the need for prompt post-exposure prophylaxis for anyone that has been bitten by a bat is essential.


Subject(s)
Chiroptera , Lyssavirus/isolation & purification , Rhabdoviridae Infections/veterinary , Animals , Epidemiological Monitoring/veterinary , Nucleocapsid Proteins/genetics , Phylogeny , Rhabdoviridae Infections/epidemiology , Rhabdoviridae Infections/virology , Sequence Analysis, DNA/veterinary , United Kingdom/epidemiology
19.
J Anim Sci ; 94(11): 4921-4929, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27898937

ABSTRACT

The objective of this study was to identify the maximum time of refrigerated storage before aerobic psychrotrophic bacteria grew to a level indicative of spoilage (7 log cfu/g) or other indicators of spoilage were observed for whole-muscle pork and ground pork sausage packaged using FreshCase technology. Pork chops and pork sausage were packaged using conventional vacuum packaging without nitrite in film (Control) or using FreshCase technology and were compared with respect to microbial counts, pH, instrumental color measurements, lipid oxidation level, and sensory properties. The storage life was 45 d for pork chops stored in FreshCase packages at 1°C and 19 d for ground pork sausage stored under the same condition. Results indicated that both pork chops and sausage stored in FreshCase packages retained redder color ( < 0.05) than those stored in Control packages. No differences ( > 0.05) existed between Control and FreshCase packaged samples for any off-odor detection for either pork chops or sausage. Moreover, levels of oxidative rancidity in all packages had low thiobarbituric acid reactive substances values. The results indicated that FreshCase technology can be used to extend storage life of pork products without having adverse effects on pork quality.


Subject(s)
Food Packaging/methods , Food Preservation/methods , Meat Products/microbiology , Red Meat/microbiology , Animals , Bacteria, Aerobic/growth & development , Oxidation-Reduction , Swine , Thiobarbituric Acid Reactive Substances/analysis
20.
Placenta ; 43: 35-40, 2016 07.
Article in English | MEDLINE | ID: mdl-27324097

ABSTRACT

OBJECTIVE: The aim of this work was to evaluate whether the uterine arteries (UtA) could be identified and their flow profiles measured during a fetal MRI examination. A comparison was performed against same day sonographic Doppler assessment. METHODS: 35 normal, healthy, singleton pregnancies at 28-32 weeks gestation underwent routine Doppler examination, followed by MRI examination. The resistivity index (RI) and pulsatility index (PI) of the left and right UtA were measured using phase contrast MRI. Bland Altman statistics were used to compare MRI and ultrasound results. RESULTS: Sixty-nine comparable vessels were analysed. Six vessels were excluded due to artefact or technical error. Bland-Altman analysis demonstrated the ultrasound indices were comparable, although systematically lower than the MRI indices; Right UtA RI bias -0.03 (95% limits of agreement (LOA) -0.27 to +0.20), and left UtA RI bias -0.06 (95% LOA -0.26 to +0.14); Right UtA PI bias -0.06 (95% LOA -0.50 to +0.38), Left UtA PI bias -0.11 (95% LOA -0.54 to +0.32). The inter-rater agreement for the MRI derived PI and RI analysis was good. CONCLUSION: This study demonstrates that in the majority of early third trimester pregnancies, the uterine arteries can be identified, and their flow profiles measured using MRI, and that the derived PI and RI values are comparable with Doppler ultrasound values.


Subject(s)
Magnetic Resonance Imaging , Pregnancy Trimester, Third/physiology , Ultrasonography, Doppler , Uterine Artery/diagnostic imaging , Vascular Resistance/physiology , Female , Humans , Pregnancy , Pulsatile Flow/physiology , Uterine Artery/physiology
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