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1.
Proc Biol Sci ; 286(1908): 20191277, 2019 08 14.
Article in English | MEDLINE | ID: mdl-31409250

ABSTRACT

Complex life cycle parasites, including helminths, use intermediate hosts for development and definitive hosts for reproduction, with interactions between the two host types governed by food web structure. I study how a parasite's intermediate host range is controlled by the diet breadth of definitive host species and the cost of parasite generalism, a putative fitness cost that assumes host range trades off against fitness derived from a host species. In spite of such costs, a benefit to generalism may occur when the definitive host exhibits a large diet breadth, enhancing transmission of generalist parasites via consumption of a broad array of infected intermediate hosts. I develop a simple theoretical model to demonstrate how different host range infection strategies are differentially selected for across a gradient of definitive host diet breadth according to the cost of generalism. I then use a parasitic helminth-host database in conjunction with a food web database to show that diet breadth of definitive hosts promotes generalist infection strategies at the intermediate host level, indicating relatively low costs of parasite generalism among helminths.


Subject(s)
Diet/veterinary , Food Chain , Helminthiasis, Animal/parasitology , Helminths/physiology , Host Specificity , Animals , Models, Biological
2.
Radiologia (Engl Ed) ; 61(1): 4-15, 2019.
Article in English, Spanish | MEDLINE | ID: mdl-30292467

ABSTRACT

Vascular malformations and tumors, also known as "vascular anomalies", comprise an extensive variety of lesions involving all parts of the body. Knowledge of their classification and imaging characteristics is paramount. Whereas hemangiomas are benign vascular tumors, characterized by cellular proliferation and hyperplasia; vascular malformations are not real tumors and characteristically exhibit normal endothelial turnover. Vascular malformations are classified according to the predominant vascular channel as arterial, capillary, venous, lymphatic, or mixed. Ultrasound and MRI are the main imaging modalities used in the diagnosis and classification of the vascular anomalies. In this series of two articles we review the classification of vascular anomalies, describe the role of imaging, summarize their distinctive histopathogenic, clinical and imaging features, and discuss the treatment options. On the first article we discuss the high-flow lesions, whereas the slow-flow lesions will be reviewed on the second. Complex syndromes with associated vascular tumors and malformations will be also presented.


Subject(s)
Soft Tissue Neoplasms/classification , Soft Tissue Neoplasms/diagnostic imaging , Vascular Malformations/classification , Vascular Malformations/diagnostic imaging , Humans , Magnetic Resonance Imaging , Regional Blood Flow , Soft Tissue Neoplasms/physiopathology , Soft Tissue Neoplasms/therapy , Ultrasonography, Doppler , Vascular Malformations/physiopathology , Vascular Malformations/therapy
3.
Radiologia (Engl Ed) ; 61(2): 124-133, 2019.
Article in English, Spanish | MEDLINE | ID: mdl-30292466

ABSTRACT

Vascular malformations and tumors, also known as "vascular anomalies", comprise an extensive variety of lesions involving all parts of the body. Due to a lack of a complete understanding of the origin and histopathology of such lesions, this field has been traditionally obscured by the use of an unclear nomenclature. Knowledge of the classification and clinical and imaging characteristics of this group of lesions is paramount when managing these patients. The objective of this series of two articles is to review the current classification of vascular anomalies, to describe the role of imaging in their diagnosis, to summarize their distinctive histopathologic, clinical and imaging features, and to discuss the treatment options. High-flow lesions were discussed in the first article of this series. In this second article, we will focus on low-flow lesions, including complex syndromes with associated low-flow malformations.


Subject(s)
Lymphatic System/abnormalities , Soft Tissue Neoplasms/diagnostic imaging , Vascular Malformations/diagnostic imaging , Adipose Tissue/blood supply , Adipose Tissue/diagnostic imaging , Humans , Klippel-Trenaunay-Weber Syndrome/diagnostic imaging , Lymphatic System/diagnostic imaging , Nevus, Blue/diagnostic imaging , Port-Wine Stain/diagnostic imaging , Port-Wine Stain/therapy , Proteus Syndrome/pathology , Regional Blood Flow , Skin Neoplasms/diagnostic imaging , Soft Tissue Neoplasms/classification , Soft Tissue Neoplasms/therapy , Sturge-Weber Syndrome/diagnostic imaging , Vascular Malformations/classification , Vascular Malformations/therapy , Veins/abnormalities
4.
Epidemics ; 26: 104-115, 2019 03.
Article in English | MEDLINE | ID: mdl-30583920

ABSTRACT

Healthcare-associated infections cause significant patient morbidity and mortality, and contribute to growing healthcare costs, whose effects may be felt most strongly in developing countries. Active surveillance systems, hospital staff compliance, including hand hygiene, and a rational use of antimicrobials are among the important measures to mitigate the spread of healthcare-associated infection within and between hospitals. Klebsiella pneumoniae is an important human pathogen that can spread in hospital settings, with some forms exhibiting drug resistance, including resistance to the carbapenem class of antibiotics, the drugs of last resort for such infections. Focusing on the role of patient movement within and between hospitals on the transmission and incidence of enterobacteria producing the K. pneumoniae Carbapenemase (KPC, an enzyme that inactivates several antimicrobials), we developed a metapopulation model where the connections among hospitals are made using a theoretical hospital network based on Brazilian hospital sizes and locations. The pathogen reproductive number, R0 that measures the average number of new infections caused by a single infectious individual, was calculated in different scenarios defined by both the links between hospital environments (regular wards and intensive care units) and between different hospitals (patient transfer). Numerical simulation was used to illustrate the infection dynamics in this set of scenarios. The sensitivity of R0 to model input parameters, such as hospital connectivity and patient-hospital staff contact rates was also established, highlighting the differential importance of factors amenable to change on pathogen transmission and control.


Subject(s)
Cross Infection/epidemiology , Drug Resistance, Multiple , Hospitals/statistics & numerical data , Patient Transfer/statistics & numerical data , Brazil/epidemiology , Humans , Intensive Care Units , Microbial Sensitivity Tests , Prevalence
5.
Proc Biol Sci ; 285(1874)2018 03 14.
Article in English | MEDLINE | ID: mdl-29514973

ABSTRACT

The distribution of parasites across mammalian hosts is complex and represents a differential ability or opportunity to infect different host species. Here, we take a macroecological approach to investigate factors influencing why some parasites show a tendency to infect species widely distributed in the host phylogeny (phylogenetic generalism) while others infect only closely related hosts. Using a database on over 1400 parasite species that have been documented to infect up to 69 terrestrial mammal host species, we characterize the phylogenetic generalism of parasites using standard effect sizes for three metrics: mean pairwise phylogenetic distance (PD), maximum PD and phylogenetic aggregation. We identify a trend towards phylogenetic specialism, though statistically host relatedness is most often equivalent to that expected from a random sample of host species. Bacteria and arthropod parasites are typically the most generalist, viruses and helminths exhibit intermediate generalism, and protozoa are on average the most specialist. While viruses and helminths have similar mean pairwise PD on average, the viruses exhibit higher variation as a group. Close-contact transmission is the transmission mode most associated with specialism. Most parasites exhibiting phylogenetic aggregation (associating with discrete groups of species dispersed across the host phylogeny) are helminths and viruses.


Subject(s)
Host Specificity , Host-Parasite Interactions , Mammals/parasitology , Animals , Phylogeny , Species Specificity
6.
J Evol Biol ; 27(8): 1650-61, 2014 08.
Article in English | MEDLINE | ID: mdl-24836646

ABSTRACT

Like many organisms, individuals of the freshwater ostracod species Eucypris virens exhibit either obligate sexual or asexual reproductive modes. Both types of individual routinely co-occur, including in the same temporary freshwater pond (their natural habitat in which they undergo seasonal diapause). Given the well-known two-fold cost of sex, this begs the question of how sexually reproducing individuals are able to coexist with their asexual counterparts in spite of such overwhelming costs. Environmental stochasticity in the form of 'false dawn' inundations (where the first hydration is ephemeral and causes loss of early hatching individuals) may provide an advantage to the sexual subpopulation, which shows greater variation in hatching times following inundation. We explore the potential role of environmental stochasticity in this system using life-history data analysis, climate data, and matrix projection models. In the absence of environmental stochasticity, the population growth rate is significantly lower in sexual subpopulations. Climate data reveal that 'false dawn' inundations are common. Using matrix projection modelling with and without environmental stochasticity, we demonstrate that this phenomenon can restore appreciable balance to the system, in terms of population growth rates. This provides support for the role of environmental stochasticity in helping to explain the maintenance of sex and the occurrence of geographical parthenogenesis.


Subject(s)
Crustacea/physiology , Environment , Models, Biological , Reproduction, Asexual/physiology , Sex , Animals , Climate , Population Dynamics , Spain , Species Specificity , Stochastic Processes
7.
Equine Vet J ; 45(6): 784-8, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23679041

ABSTRACT

Mathematical modelling of infectious disease is increasingly regarded as an important tool in the development of disease prevention and control measures. This article brings together key findings from various modelling studies conducted over the past 10 years that are of relevance to those on the front line of the battle against equine influenza.


Subject(s)
Horse Diseases/prevention & control , Models, Biological , Orthomyxoviridae Infections/veterinary , Animals , Horses , Influenza Vaccines/immunology , Orthomyxoviridae Infections/prevention & control
8.
Cardiovasc Intervent Radiol ; 36(4): 1068-72, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23152040

ABSTRACT

PURPOSE: This study describes and evaluated the effectiveness of occluding distal ureters in the clinical setting of urinary vaginal (vesicovaginal or enterovesicovaginal) fistulae utilizing a new technique which combines Amplatzer vascular plugs and N-butyl cyanoacrylate. MATERIALS: This is a retrospective study (January 2007-December 2010) of patients with urinary-vaginal fistulae undergoing distal ureter embolization utilizing an Amplatzer-N-butyl cyanoacrylate-Amplatzer sandwich technique. An 8-12-mm type-I or type-II Amplatzer vascular plug was delivered using the sheath and deployed in the ureter distal to the pelvic brim. Instillation of 0.8-1.5 cc of N-butyl cyanoacrylate into ureter proximal to the Amplatzer plug was performed. This was followed by another set of 8-12-mm type-I or type-II Amplatzer vascular plugs in a technique referred to as the "sandwich technique." RESULTS: Five ureters in three patients were occluded utilizing the above-described technique during the 4-year study period. Mean maximum size Amplatzer used per ureter was 10.8 mm (range, 8-12). One ureter required three Amplatzer plugs and the rest required two. Two patients (3 ureters) were clinically successful with complete resolution of symptoms in 36-48 h. The third patient (2 ureters) was partly successful and required a second Amplatzer-N-butyl cyanoacrylate sandwich technique embolization. The mean clinical follow-up was 11.3 months (range, 1.7-29.2). CONCLUSIONS: The Amplatzer-N-butyl cyanoacrylate-Amplatzer sandwich technique for occluding the distal ureter is safe and effective with a quick (probably due to the N-butyl cyanoacrylate) and durable (probably due to the Amplatzer plugs) clinical response.


Subject(s)
Embolization, Therapeutic/methods , Enbucrilate/therapeutic use , Septal Occluder Device , Ureteral Diseases/therapy , Vesicovaginal Fistula/therapy , Adult , Aged , Cohort Studies , Female , Follow-Up Studies , Humans , Middle Aged , Retrospective Studies , Risk Assessment , Treatment Outcome , Urinary Bladder Fistula/diagnosis , Urinary Bladder Fistula/therapy , Urinary Catheterization/instrumentation , Urinary Catheterization/methods , Vesicovaginal Fistula/diagnosis
9.
Thrombosis ; 2011: 246410, 2011.
Article in English | MEDLINE | ID: mdl-22254138

ABSTRACT

Purpose. To evaluate the safety and efficacy of the Possis rheolytic thrombectomy with or without indwelling catheter-directed pharmacolysis for the treatment of massive pulmonary embolus in patients presenting with right heart strain and/or a pulseless electrical activity (PEA). Materials and Methods. Retrospective review of patients undergoing pulmonary pharmacolysis was performed (07/2004-06/2009). Pre- and posttreatment Miller index scoring weres calculated and compared. Patients were evaluated for tPA doses, ICU stay, hospital stay, and survival by Kaplan-Meier analysis. Results. 11 patients with massive PE were found, with 10/11 presenting with a Miller score of >17 (range: 16-27, mean: 23.2). CTPA and/or echocardiographic evidence of right heart strain was found in 10/11 patients. 3 (27%) patients presented with a PEA event. Two (18%) patients had a contraindication to pharmacolysis and were treated with mechanical thrombectomy alone. The intraprocedural mortality was 9% (n = 1/11). Of the 10 patients who survived the initial treatment, 7 patients underwent standard mechanical thrombectomy initially, while 5 received power pulse spray mechanical thrombectomy. Eight of these 10 patients underwent adjunctive indwelling catheter-directed thrombolysis. The mean catheter-directed infusion duration was 18 hours (range of 12-26 hours). The average intraprocedural, infusion, and total doses of tPA were 7 mg, 19.7 mg, and 26.7 mg, respectively. There was a 91% (10/11) technical success rate. The failure was the single mortality. Average reduction in Miller score was 9.5 or 41% (P = 0.009), obstructive index of 6.4 or 47% (P = 0.03), and perfusion index of 2.7 or 28% (P = 0.05). Average ICU and hospital stay were 7.4 days (range 2-27 days) and 21.3 days (range 6-60 days), respectively. Intent to treat survival was 90% at 6, 12, and 18 months. Conclusion. Rheolytic thrombectomy with or without adjunctive catheter-directed thrombolysis provides a safe and effective method for treatment of acute PE in patients who present with right heart strain and/or a PEA event.

10.
J Evol Biol ; 23(5): 1013-23, 2010 May.
Article in English | MEDLINE | ID: mdl-20345815

ABSTRACT

The restrictive assumptions associated with purely genetic and purely ecological mechanisms suggest that neither of the two forces, in isolation, can offer a general explanation for the evolutionary maintenance of sex. Consequently, attention has turned to pluralistic models (i.e. models that apply both ecological and genetic mechanisms). Existing research has shown that combining mutation accumulation and parasitism allows restrictive assumptions about genetic and parasite parameter values to be relaxed while still predicting the maintenance of sex. However, several empirical studies have shown that deleterious mutations and parasitism can reduce fitness to a greater extent than would be expected if the two acted independently. We show how interactions between these genetic and ecological forces can completely reverse predictions about the evolution of reproductive modes. Moreover, we demonstrate that synergistic interactions between infection and deleterious mutations can render sex evolutionarily stable even when there is antagonistic epistasis among deleterious mutations, thereby widening the conditions for the evolutionary maintenance of sex.


Subject(s)
Biological Evolution , Genetic Fitness/genetics , Models, Genetic , Mutation/genetics , Parasites , Sex , Animals , Computer Simulation
11.
Br J Radiol ; 79(947): e171-3, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17065280

ABSTRACT

This report describes a bronchial artery originating from the left gastric artery in a patient with recurrent massive haemoptysis caused by chronic pulmonary tuberculosis. The artery was not evident on the initial angiographic work-up including thoracic aortography, but it was evident in the selective angiography upon follow-up study. Haemoptysis was successfully controlled with transarterial embolisation. The left gastric artery should be included as a location for the possible origin of the bronchial artery.


Subject(s)
Bronchial Arteries/abnormalities , Hemoptysis/etiology , Stomach/blood supply , Tuberculosis, Pulmonary/complications , Bronchial Arteries/diagnostic imaging , Chronic Disease , Hemoptysis/diagnostic imaging , Humans , Male , Middle Aged , Radiography , Tuberculosis, Pulmonary/diagnostic imaging
12.
Vet Rec ; 157(2): 41-6, 2005 Jul 09.
Article in English | MEDLINE | ID: mdl-16006639

ABSTRACT

The transmission of contagious equine metritis (CEM) on stud farms in Britain, Ireland and other European countries is prevented by following the recommendations in the Horserace Betting Levy Board's Code of Practice on CEM. A quantitative risk assessment was undertaken to estimate the likely impact of removing the recommendation, from the 2002 code, to culture endometrial or cervical swabs microaerophilically for the presence of Taylorella equigenitalis, the causative organism. The scientific literature was reviewed for evidence about the anatomical distribution of T. equigenitalis at different times after infection and it was found that, in chronically infected mares, the organism was detectable in the clitoral swabs of nearly 93 per cent, but in the cervical swabs of only 31 per cent. In contrast, in acutely infected mares, the organism was detectable in the clitoral swabs of nearly 69 per cent, but in the cervical swabs of 84 per cent. By using these results, a quantitative risk assessment was undertaken, assessing the likely effects of removing the recommendation that swabs from the cervix of low-risk mares should be cultured for T. equigenitalis. The results were sensitive to the prevalence of the infection, but when it was low, there appeared to be few benefits in continuing to culture cervical swabs routinely. However, such swabs are vital when the disease is suspected.


Subject(s)
Gram-Negative Bacterial Infections/veterinary , Horse Diseases/microbiology , Taylorella equigenitalis/isolation & purification , Algorithms , Animals , Carrier State/veterinary , Endometritis/microbiology , Endometritis/prevention & control , Endometritis/veterinary , Female , Gram-Negative Bacterial Infections/diagnosis , Gram-Negative Bacterial Infections/prevention & control , Horse Diseases/epidemiology , Horse Diseases/prevention & control , Horses , Risk Assessment
13.
Proc Biol Sci ; 271(1548): 1547-55, 2004 Aug 07.
Article in English | MEDLINE | ID: mdl-15306299

ABSTRACT

We assess the effects of strain heterology (strains that are immunologically similar but not identical) on equine influenza in a vaccinated population. Using data relating to individual animals, for both homologous and heterologous vaccinees, we estimate distributions for the latent and infectious periods, quantify the risk of becoming infected in terms of the quantity of cross-reactive antibodies to a key surface protein of the virus (haemagglutinin) and estimate the probability of excreting virus (i.e. becoming infectious) given that infection has occurred. The data suggest that the infectious period, the risk of becoming infected (for a given vaccine-induced level of cross-reactive antibodies) and the probability of excreting virus are increased for heterologously vaccinated animals when compared with homologously vaccinated animals. The data are used to parameterize a modified susceptible, exposed, infectious and recovered/resistant (SEIR) model, which shows that these relatively small differences combine to have a large effect at the population level, where populations of heterologous vaccinees face a significantly increased risk of an epidemic occurring.


Subject(s)
Antibodies, Viral/immunology , Antigens, Heterophile/immunology , Horse Diseases/virology , Influenza A virus/immunology , Models, Immunological , Orthomyxoviridae Infections/veterinary , Vaccination/veterinary , Animals , Computer Simulation , Cross Reactions/immunology , Hemagglutinin Glycoproteins, Influenza Virus/immunology , Horse Diseases/epidemiology , Horse Diseases/immunology , Horse Diseases/prevention & control , Horses , Monte Carlo Method , Orthomyxoviridae Infections/epidemiology , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/prevention & control , Risk Assessment , Species Specificity
15.
Vaccine ; 21(21-22): 2862-70, 2003 Jun 20.
Article in English | MEDLINE | ID: mdl-12798628

ABSTRACT

A stochastic model of equine influenza (EI) is constructed to assess the risk of an outbreak in a Thoroughbred population at a typical flat race training yard. The model is parameterised using data from equine challenge experiments conducted by the Animal Health Trust (relating to the latent and infectious period of animals) and also published data on previous epidemics (to estimate the transmission rate for equine influenza). Using 89 ponies, an empirical relationship between pre-challenge antibody and the probability of becoming infectious is established using logistic regression. Changes in antibody level over time are quantified using published and unpublished studies comprising 618 ponies and horses. A plausible Thoroughbred population is examined over the course of a year and the model is used to assess the risk of an outbreak of EI in the yard under the current minimum vaccination policy in the UK. The model is adapted to consider an alternative vaccination programme where the frequency of vaccination in older horses (2-year-olds and upwards) is increased. Model results show that this practical alternative would offer a significant increase in protection. Spread of infection between yards is also considered to ascertain the risk of secondary outbreaks.


Subject(s)
Horse Diseases/prevention & control , Influenza Vaccines/immunology , Orthomyxoviridae Infections/veterinary , Vaccination/veterinary , Age Factors , Animals , Disease Outbreaks/veterinary , Horse Diseases/epidemiology , Horse Diseases/transmission , Horses , Influenza Vaccines/administration & dosage , Models, Biological , Orthomyxoviridae Infections/epidemiology , Orthomyxoviridae Infections/immunology , Physical Conditioning, Animal , Time Factors
18.
J Nihon Univ Sch Dent ; 33(4): 211-43, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1787417

ABSTRACT

Belief in a golden age has provided mankind with solace in times of despair and with élan during the expansive periods of history. Dreamers imagine the golden age in the remote past, in paradise lost, free from toil and grief. Optimists put their faith in the future and believe that mankind, Prometheus-like, will master the arts of life through power and knowledge. Thus, the golden age means different things to different men, but the very belief in its existence implies the conviction that perfect health and happiness are birthrights of men. Yet, in reality, complete freedom from disease and from struggle is almost incompatible with the process of living.


Subject(s)
Mouth Diseases/history , Paleodontology , Paleopathology , Tooth Diseases/history , Africa , Animal Diseases/history , Animals , Animals, Domestic , Asia , Bone Diseases/history , Europe , Facial Bones , History, Ancient , Humans , Mouth Diseases/veterinary , Tooth Diseases/veterinary
19.
Eur J Morphol ; 29(1): 41-52, 1991.
Article in English | MEDLINE | ID: mdl-2059556

ABSTRACT

An assessment of the growth rate pattern based on longitudinal weight data of guinea pigs was conducted over the presumptive preweaning and early postweaning period. The study covered the minimum of 44 and maximum of 53 days with means calculated for 3-day intervals involving 13 litters and a total of 40 young. Initial analysis showed males heavier than females at birth and both sexes being inversely proportional to litter size at birth. At the end of the experimental period the males were still heavier than the females but their weight distribution peaked in litter of three while the females were heaviest in the largest litters of five and lightest in the litter of one. Phasic linear regression line analysis revealed 4 litters with a triphasic growth outline and 6 litters with quadrophasic growth outline. Final assessments indicate that the total period of 53 days manifests a quadrophasic growth outline while, in contrast, the period specifically involved with the process of lactation and weaning displays a definite diphasic growth spectrum and is comparable to the tri- or quadrophasic spectrum occurring in the albino rats, rice rats and hamsters.


Subject(s)
Animals, Newborn/growth & development , Animals, Suckling/growth & development , Weight Gain/physiology , Age Factors , Animals , Guinea Pigs , Litter Size , Regression Analysis , Sex Factors , Weaning
20.
J Nihon Univ Sch Dent ; 32(3): 175-80, 1990 Sep.
Article in English | MEDLINE | ID: mdl-2230960

ABSTRACT

Among 350 inhabitants of two villages, 31 (8.9%) cleaned their teeth using table salt and charcoal applied to their forefinger or a Melastoma brush. As a result, all had distinct forms of abrasion cavity on the labial surfaces of their teeth. All of the above three agents are highly abrasive and injurious to both the hard and soft oral tissues. This dying practice is only popular among a very small number of persons in the older age group, and should be discouraged.


Subject(s)
Tooth Abrasion/etiology , Adult , Charcoal/adverse effects , Gingival Diseases/etiology , Humans , Malaysia , Medicine, Traditional , Middle Aged , Plants , Sodium Chloride/adverse effects , Toothbrushing/instrumentation
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