RESUMO
Dehydration is a taphonomic process that affects nearly all skeletal remains, yet there is a dearth of evidence on this process within the forensic taphonomy literature. When considering the forensic implications of skeletal dehydration, a particular area of concern is sharp force trauma due to its global prominence in forensic cases. In an attempt to address these literature gaps and quantify the effects that dehydration has on skeletal elements, a controlled experiment subjected Sus domesticus (i.e., domestic pig) radii samples (n = 36) to laboratory-induced dehydration after they were inflicted with knife trauma. All samples were photographed pre- and post-dehydration; bone section and kerf mark length, width, and area were then measured from these photographs using ImageJ. Statistical analysis of pre- and post-dehydration samples showed that all measurements experienced significant (p ≤ 0.001) shrinkage, with bone sample area shrinking an average of 8.8 % and kerf mark area an average of 29.7 %. Alterations in length, width and area between the kerf marks and bone samples showed a weak, moderate, and strong correlation, respectively. These findings suggest that anthropological analysis may be affected by dehydration-induced shrinkage, highlighting the necessity of continued research into the effects of dehydration on skeletal trauma.
Assuntos
Desidratação , Ferimentos Perfurantes , Suínos , Animais , Restos Mortais , Osso e Ossos , Sus scrofa , Antropologia ForenseRESUMO
BACKGROUND: In the absence of a method to culture Plasmodium vivax, the only way to source parasites is ex vivo. This hampers many aspects of P. vivax research. This study aimed to assess the safety of apheresis, a method for selective removal of specific components of blood as a means of extracting and concentrating P. vivax parasites. METHODS: An iterative approach was employed across four non-immune healthy human subjects in single subject cohorts. All four subjects were inoculated with ~ 564 blood stage P. vivax (HMP013-Pv) and subjected to apheresis 10 to 11 days later. Blood samples collected during apheresis (haematocrit layers 0.5% to 11%) were tested for the presence and concentration of P. vivax by microscopy, flow cytometry, 18S rDNA qPCR for total parasites, and pvs25 qRT-PCR for female gametocyte transcripts. Safety was determined by monitoring adverse events. Malaria transmission to mosquitoes was assessed by membrane feeding assays. RESULTS: There were no serious adverse events and no significant safety concerns. Apheresis concentrated asexual parasites by up to 4.9-fold (range: 0.9-4.9-fold) and gametocytes by up to 1.45-fold (range: 0.38-1.45-fold) compared to pre-apheresis densities. No single haematocrit layer contained > 40% of all the recovered P. vivax asexual parasites. Ex vivo concentration of parasites by Percoll gradient centrifugation of whole blood achieved greater concentration of gametocytes than apheresis. Mosquito transmission was enhanced by up to fivefold in a single apheresis sample compared to pre-apheresis. CONCLUSION: The modest level of parasite concentration suggests that the use of apheresis may not be an ideal method for harvesting P. vivax. Trial Registration Australia New Zealand Clinical Trials Registry (ANZCTR) Trial ID: ACTRN12617001502325 registered on 19th October 2017. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373812.
Assuntos
Remoção de Componentes Sanguíneos/estatística & dados numéricos , Malária Vivax/parasitologia , Parasitemia/parasitologia , Plasmodium vivax/isolamento & purificação , Adulto , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Segurança , Adulto JovemRESUMO
BACKGROUND: Artemisinin monotherapy of Plasmodium falciparum infection is frequently ineffective due to recrudescence. Artemisinin-induced dormancy, shown in vitro and in animal models, provides a plausible explanation. To date, direct evidence of artemisinin-induced dormancy in humans is lacking. METHODS: Blood samples were collected from Plasmodium falciparum 3D7- or K13-infected participants before and 48-72 hours after single-dose artesunate (AS) treatment. Parasite morphology, molecular signature of dormancy, capability and dynamics of seeding in vitro cultures, and genetic mutations in the K13 gene were investigated. RESULTS: Dormant parasites were observed in post-AS blood samples of 3D7- and K13-infected participants. The molecular signature of dormancy, an up-regulation of acetyl CoA carboxylase, was detected in 3D7 and K13 samples post-AS, but not in pre-AS samples. Posttreatment samples successfully seeded in vitro cultures, with a significant delay in time to reach 2% parasitemia compared to pretreatment samples. CONCLUSIONS: This study provides strong evidence for the presence of artemisinin-induced dormant parasites in P. falciparum infections. These parasites are a likely reservoir for recrudescent infection following artemisinin monotherapy and artemisinin combination therapy (ACT). Combination regimens that target dormant parasites or remain at therapeutic levels for a sufficient time to kill recovering parasites will likely improve efficacy of ACTs.
Assuntos
Antimaláricos , Artesunato , Malária Falciparum , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Artesunato/uso terapêutico , Resistência a Medicamentos/efeitos dos fármacos , Humanos , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Proteínas de ProtozoáriosRESUMO
BACKGROUND: Artemisinin derivatives are the leading class of antimalarial drugs due to their rapid onset of action and rapid clearance of circulating parasites. The parasite clearance half-life measures the rate of loss of parasites from blood after treatment, and this is currently used to assess antimalarial activity of novel agents and to monitor resistance. However, a number of recent studies have challenged the use of parasite clearance to measure drug activity, arguing that many circulating parasites may be nonviable. METHODS: Plasmodium falciparum-infected subjects (n = 10) in a malaria volunteer infection study were administered a single dose of artesunate (2 mg/kg). Circulating parasite concentration was assessed by means of quantitative polymerase chain reaction (qPCR). Parasite viability after artesunate administration was estimated by mathematical modeling of the ex vivo growth of parasites collected from subjects. RESULTS: We showed that in artemisinin-sensitive infection, viable parasites declined to <0.1% of baseline within 8 hours after artesunate administration, while the total number of circulating parasites measured with quantitative polymerase chain reaction remained unchanged. In artemisinin-resistant infections over the same interval, viable parasites declined to 51.4% (standard error of the mean, 4.6%) of baseline. CONCLUSIONS: These results demonstrate that in vivo drug activity of artesunate is faster than is indicated by the parasite clearance half-life.
Assuntos
Antimaláricos , Artemisininas , Artesunato , Malária Falciparum , Plasmodium falciparum , Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Artesunato/uso terapêutico , Resistência a Medicamentos , Humanos , Malária Falciparum/tratamento farmacológico , Modelos Teóricos , Plasmodium falciparum/efeitos dos fármacosRESUMO
BACKGROUND: Artemisinin resistance is threatening malaria control. We aimed to develop and test a human model of artemisinin-resistant (ART-R) Plasmodium falciparum to evaluate the efficacy of drugs against ART-R malaria. METHODS AND FINDINGS: We conducted 2 sequential phase 1, single-centre, open-label clinical trials at Q-Pharm, Brisbane, Australia, using the induced blood-stage malaria (IBSM) model, whereby healthy participants are intravenously inoculated with blood-stage parasites. In a pilot study, participants were inoculated (Day 0) with approximately 2,800 viable P. falciparum ART-R parasites. In a comparative study, participants were randomised to receive approximately 2,800 viable P. falciparum ART-R (Day 0) or artemisinin-sensitive (ART-S) parasites (Day 1). In both studies, participants were administered a single approximately 2 mg/kg oral dose of artesunate (AS; Day 9). Primary outcomes were safety, ART-R parasite infectivity, and parasite clearance. In the pilot study, 2 participants were enrolled between April 27, 2017, and September 12, 2017, and included in final analyses (males n = 2 [100%], mean age = 26 years [range, 23-28 years]). In the comparative study, 25 participants were enrolled between October 26, 2017, and October 18, 2018, of whom 22 were inoculated and included in final analyses (ART-R infected participants: males n = 7 [53.8%], median age = 22 years [range, 18-40 years]; ART-S infected participants: males n = 5 [55.6%], median age = 28 years [range, 22-35 years]). In both studies, all participants inoculated with ART-R parasites became parasitaemic. A total of 36 adverse events were reported in the pilot study and 277 in the comparative study. Common adverse events in both studies included headache, pyrexia, myalgia, nausea, and chills; none were serious. Seven participants experienced transient severe falls in white cell counts and/or elevations in liver transaminase levels which were considered related to malaria. Additionally, 2 participants developed ventricular extrasystoles that were attributed to unmasking of a predisposition to benign fever-induced tachyarrhythmia. In the comparative study, parasite clearance half-life after AS was significantly longer for ART-R infected participants (n = 13, 6.5 hours; 95% confidence interval [CI] 6.3-6.7 hours) compared with ART-S infected participants (n = 9, 3.2 hours; 95% CI 3.0-3.3 hours; p < 0.001). The main limitation of this study was that the ART-R and ART-S parasite strains did not share the same genetic background. CONCLUSIONS: We developed the first (to our knowledge) human model of ART-R malaria. The delayed clearance profile of ART-R parasites after AS aligns with field study observations. Although based on a relatively small sample size, results indicate that this model can be safely used to assess new drugs against ART-R P. falciparum. TRIAL REGISTRATION: The studies were registered with the Australian New Zealand Clinical Trials Registry: ACTRN12617000244303 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372357) and ACTRN12617001394336 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373637).
Assuntos
Anti-Infecciosos/uso terapêutico , Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Malária Falciparum/sangue , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/metabolismo , Adolescente , Adulto , Animais , Anti-Infecciosos/efeitos adversos , Anti-Infecciosos/farmacologia , Antimaláricos/efeitos adversos , Antimaláricos/farmacologia , Artemisininas/efeitos adversos , Artemisininas/farmacologia , Artesunato/efeitos adversos , Artesunato/farmacologia , Artesunato/uso terapêutico , Austrália/epidemiologia , Feminino , Cefaleia/induzido quimicamente , Voluntários Saudáveis , Humanos , Malária Falciparum/epidemiologia , Masculino , Náusea/induzido quimicamente , Parasitos/metabolismo , Projetos Piloto , Adulto JovemRESUMO
BACKGROUND: Plasmodium malariae is considered a minor malaria parasite, although its global disease burden is underappreciated. The aim of this study was to develop an induced blood-stage malaria (IBSM) model of P. malariae to study parasite biology, diagnostic assays, and treatment. METHODS: This clinical trial involved 2 healthy subjects who were intravenously inoculated with cryopreserved P. malariae-infected erythrocytes. Subjects were treated with artemether-lumefantrine after development of clinical symptoms. Prior to antimalarial therapy, mosquito-feeding assays were performed to investigate transmission, and blood samples were collected for rapid diagnostic testing and parasite transcription profiling. Serial blood samples were collected for biomarker analysis. RESULTS: Both subjects experienced symptoms and signs typical of early malaria. Parasitemia was detected 7 days after inoculation, and parasite concentrations increased until antimalarial treatment was initiated 25 and 21 days after inoculation for subjects 1 and 2 respectively (peak parasitemia levels, 174 182 and 50 291 parasites/mL, respectively). The parasite clearance half-life following artemether-lumefantrine treatment was 6.7 hours. Mosquito transmission was observed for 1 subject, while in vivo parasite transcription and biomarkers were successfully profiled. CONCLUSIONS: An IBSM model of P. malariae has been successfully developed and may be used to study the biology of, diagnostic testing for, and treatment of this neglected malaria species. CLINICAL TRIALS REGISTRATION: ACTRN12617000048381.
Assuntos
Antimaláricos/uso terapêutico , Combinação Arteméter e Lumefantrina/uso terapêutico , Malária/sangue , Malária/parasitologia , Plasmodium malariae/genética , Adolescente , Animais , Anopheles/parasitologia , Comportamento Alimentar , Humanos , Malária/patologia , Masculino , Parasitemia/sangue , Parasitemia/tratamento farmacológico , Parasitemia/parasitologia , Plasmodium malariae/fisiologia , Transcriptoma , Adulto JovemRESUMO
Vitamin D deficiency rickets was considered endemic in the industrialized cities of 19th century England, but was rarely reported in more rural and suburban areas. The commercial excavation of St. John's Church, Redhill, Surrey, UK provided an opportunity to examine to what extent suburban children were affected by rickets and the factors responsible for its development. Seventy-nine non-adults (0-17 years) from St. John's Church were subjected to macroscopic and radiographic analysis to identify skeletal manifestations of vitamin D deficiency. Rachitic lesions were identified in 14/79 individuals (17.7%) aged from six months to six years. Active cases occurred from six months to two years of age with healed cases observed from three to six years. One seven month old infant also displayed healed lesions. The age-specific pattern of active and healed rickets suggests the population was vulnerable to the seasonal restriction of sunlight hours, with the considerably low vitamin D content of the infant diet unable to provide sufficient amounts to maintain metabolic functions. This research demonstrates that rickets was not simply a disease of industrialization but that a variety of factors contributed to its development in groups previously considered to be low risk.
Assuntos
Raquitismo/etiologia , Raquitismo/história , Deficiência de Vitamina D/etiologia , Deficiência de Vitamina D/história , Pré-Escolar , Inglaterra , História do Século XIX , Humanos , Lactente , Raquitismo/patologia , População Suburbana , Deficiência de Vitamina D/patologiaRESUMO
This study examined the effect of time pressure on face-matching accuracy. Across two experiments, observers decided whether pairs of faces depict one person or different people. Time pressure was exerted via two additional displays, which were constantly updated to inform observers on whether they were on track to meet or miss a time target. In this paradigm, faces were matched under increasing or decreasing (Experiment 1) and constant time pressure (Experiment 2), which varied from 10 to 2 seconds. In both experiments, time pressure reduced accuracy, but the point at which this declined varied from 8 to 2 seconds. A separate match response bias was found, which developed over the course of the experiments. These results indicate that both time pressure and the repetitive nature of face matching are detrimental to performance.
RESUMO
OBJECTIVES: This study provides the first large scale analysis of the age at which adolescents in medieval England entered and completed the pubertal growth spurt. This new method has implications for expanding our knowledge of adolescent maturation across different time periods and regions. METHODS: In total, 994 adolescent skeletons (10-25 years) from four urban sites in medieval England (AD 900-1550) were analyzed for evidence of pubertal stage using new osteological techniques developed from the clinical literature (i.e., hamate hook development, cervical vertebral maturation (CVM), canine mineralization, iliac crest ossification, and radial fusion). RESULTS: Adolescents began puberty at a similar age to modern children at around 10-12 years, but the onset of menarche in girls was delayed by up to 3 years, occurring around 15 for most in the study sample and 17 years for females living in London. Modern European males usually complete their maturation by 16-18 years; medieval males took longer with the deceleration stage of the growth spurt extending as late as 21 years. CONCLUSIONS: This research provides the first attempt to directly assess the age of pubertal development in adolescents during the 10th-17th centuries. Poor diet, infections, and physical exertion may have contributed to delayed development in the medieval adolescents, particularly for those living in the city of London. This study sheds new light on the nature of adolescence in the medieval period, highlighting an extended period of physical and social transition.
Assuntos
Determinação da Idade pelo Esqueleto/métodos , Arqueologia/métodos , Puberdade , Maturidade Sexual , Adolescente , Criança , Inglaterra , Feminino , História do Século XV , História do Século XVI , História do Século XVII , História Medieval , Humanos , Masculino , Adulto JovemRESUMO
OBJECTIVES: Episodes of ill-health in childhood can predispose affected individuals to further periods of illness and early adult mortality. This study uses nonspecific indicators of stress to examine how growth disruptions during infancy/early childhood, and late childhood/early adolescence affected adult longevity in later medieval and post-medieval London. MATERIALS AND METHODS: Hazards analysis was used to evaluate the effect of linear enamel hypoplasia (LEH) and the size of the anteroposterior (AP) and transverse (TR) diameters of the vertebral neural canal (VNC) on adult age-at-death. This was applied to skeletal samples from later medieval (n = 461) and post-medieval (n = 480) London. RESULTS: Growth disruptions during infancy/early childhood (LEH and AP VNC diameters) were not associated with longevity, or with impaired growth at later stages of development (TR VNC diameters). Growth disruptions during late childhood/early adolescence (TR VNC diameters) were associated with a significantly increased risk of adult mortality. DISCUSSION: Macroscopic hypoplasia represent short periods of stress during infancy/early childhood which did not disrupt future investments in growth or cause long-term damage to health. Small TR diameters represent chronic stress during late childhood/early adolescence which resulted in greater susceptibility to infections and increased risk of mortality. These interactions were influenced by sex and socioeconomic status, suggesting that socioeconomic circumstances in both childhood and adult life could influence exposure and resistance to stressors.
Assuntos
Desenvolvimento Infantil/fisiologia , Mortalidade/história , Estresse Fisiológico/fisiologia , Adolescente , Adulto , Antropologia Física , Criança , Hipoplasia do Esmalte Dentário/história , Hipoplasia do Esmalte Dentário/patologia , Feminino , História Medieval , Humanos , Londres , Masculino , Pessoa de Meia-Idade , Canal Medular/anatomia & histologia , Adulto JovemRESUMO
Urinary tract infections (UTIs) are among the most common infectious diseases of humans, with Escherichia coli responsible for >80% of all cases. One extreme of UTI is asymptomatic bacteriuria (ABU), which occurs as an asymptomatic carrier state that resembles commensalism. To understand the evolution and molecular mechanisms that underpin ABU, the genome of the ABU E. coli strain VR50 was sequenced. Analysis of the complete genome indicated that it most resembles E. coli K-12, with the addition of a 94-kb genomic island (GI-VR50-pheV), eight prophages, and multiple plasmids. GI-VR50-pheV has a mosaic structure and contains genes encoding a number of UTI-associated virulence factors, namely, Afa (afimbrial adhesin), two autotransporter proteins (Ag43 and Sat), and aerobactin. We demonstrated that the presence of this island in VR50 confers its ability to colonize the murine bladder, as a VR50 mutant with GI-VR50-pheV deleted was attenuated in a mouse model of UTI in vivo. We established that Afa is the island-encoded factor responsible for this phenotype using two independent deletion (Afa operon and AfaE adhesin) mutants. E. coli VR50afa and VR50afaE displayed significantly decreased ability to adhere to human bladder epithelial cells. In the mouse model of UTI, VR50afa and VR50afaE displayed reduced bladder colonization compared to wild-type VR50, similar to the colonization level of the GI-VR50-pheV mutant. Our study suggests that E. coli VR50 is a commensal-like strain that has acquired fitness factors that facilitate colonization of the human bladder.
Assuntos
Adaptação Biológica , Bacteriúria/microbiologia , Portador Sadio/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/genética , Evolução Molecular , Sistema Urinário/microbiologia , Adulto , Animais , Aderência Bacteriana , Linhagem Celular , DNA Bacteriano/química , DNA Bacteriano/genética , Células Epiteliais/microbiologia , Escherichia coli/isolamento & purificação , Feminino , Genoma Bacteriano , Humanos , Camundongos Endogâmicos C57BL , Modelos Animais , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
Iron acquisition is an important aspect of the host-pathogen interaction. In the case of Salmonella it is established that catecholate siderophores are important for full virulence. In view of their very high affinity for ferric iron, functional studies of siderophores have been almost exclusively focused on their role in acquisition of iron from the host. In the present study, we investigated whether the siderophores (enterobactin and salmochelin) produced by Salmonella enterica sv. Typhimurium could act as antioxidants and protect from the oxidative stress encountered after macrophage invasion. Our results show that the ability to produce siderophores enhanced the survival of Salmonella in the macrophage mainly at the early stages of infection, coincident with the oxidative burst. Using siderophore biosynthetic and siderophore receptor mutants we demonstrated that salmochelin and enterobactin protect S. Typhimurium against ROS (reactive oxygen species) in vitro and that siderophores must be intracellular to confer full protection. We also investigated whether other chemically distinct siderophores (yersiniabactin and aerobactin) or the monomeric catechol 2,3-dihydroxybenzoate could provide protection against oxidative stress and found that only catecholate siderophores have this property. Collectively, the results of the present study identify additional functions for siderophores during host-pathogen interactions.
Assuntos
Antioxidantes/fisiologia , Enterobactina/análogos & derivados , Enterobactina/fisiologia , Salmonella typhimurium/metabolismo , Sideróforos/fisiologia , Catecóis/metabolismo , Glucosídeos , Peróxido de Hidrogênio/metabolismo , Ferro/fisiologia , Oxidantes/metabolismo , Salmonella typhimurium/crescimento & desenvolvimentoRESUMO
Aponogeton madagascariensis produces perforations over its leaf surface via programmed cell death (PCD). PCD begins between longitudinal and transverse veins at the center of spaces regarded as areoles, and continues outward, stopping several cells from these veins. The gradient of PCD that exists within a single areole of leaves in an early stage of development was used as a model to investigate cellular dynamics during PCD. Mitochondria have interactions with a family of proteases known as caspases, and the actin cytoskeleton during metazoan PCD; less is known regarding these interactions during plant PCD. This study employed the actin stain Alexa Fluor 488 phalloidin, the actin depolymerizer Latrunculin B (Lat B), a synthetic caspase peptide substrate and corresponding specific inhibitors, as well as the mitochondrial pore inhibitor cyclosporine A (CsA) to analyze the role of these cellular constituents during PCD. Results depicted that YVADase (caspase-1) activity is higher during the very early stages of perforation formation, followed by the bundling and subsequent breakdown of actin. Actin depolymerization using Lat B caused no change in YVADase activity. In vivo inhibition of YVADase activity prevented PCD and actin breakdown, therefore substantiating actin as a likely substrate for caspase-like proteases (CLPs). The mitochondrial pore inhibitor CsA significantly decreased YVADase activity, and prevented both PCD and actin breakdown; therefore suggesting the mitochondria as a possible trigger for CLPs during PCD in the lace plant. To our knowledge, this is the first in vivo study using either caspase-1 inhibitor (Ac-YVAD-CMK) or CsA, following which the actin cytoskeleton was examined. Overall, our findings suggest the mitochondria as a possible upstream activator of YVADase activity and implicate these proteases as potential initiators of actin breakdown during perforation formation via PCD in the lace plant.
Assuntos
Citoesqueleto de Actina/metabolismo , Alismatales/citologia , Alismatales/enzimologia , Apoptose , Caspases/metabolismo , Mitocôndrias/metabolismo , Citoesqueleto de Actina/efeitos dos fármacos , Actinas/metabolismo , Alismatales/efeitos dos fármacos , Alismatales/crescimento & desenvolvimento , Apoptose/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Inibidores de Caspase/farmacologia , Ciclosporina/farmacologia , Cinética , Mitocôndrias/efeitos dos fármacos , Folhas de Planta/citologia , Folhas de Planta/crescimento & desenvolvimento , Polimerização/efeitos dos fármacos , Tiazolidinas/farmacologiaRESUMO
Changing patterns of stress indicators were used to examine the impact of external biocultural changes on childhood development and to explore the association between developmental health and adult longevity in a small market town in Lincolnshire, England. Cribra orbitalia, linear enamel hypoplasias (LEH), vertebral neural canal (VNC) size, craniofacial fluctuating asymmetry and femoral length were recorded in 267 adult skeletons dating from an earlier agricultural community (n=157) (AD1150-1700) and a later urbanised, middle-class community (n=110) (AD1700-1855) buried at St. Peter's Church, Barton-upon-Humber. The only stress indicator to display a statistical difference between periods was VNC size, which increased significantly in AD1700-1855. Analysis of stress indicators according to adult age-at-death revealed that cribra orbitalia, small VNC diameter and short femoral length in males and cribra orbitalia and craniofacial asymmetry in females were associated with a younger age-at-death in AD1150-1700. During AD1700-1855 both sexes showed selectivity for small VNC size. This demonstrates that external biocultural changes at Barton-upon-Humber had limited impact on growth, but did alter the long term sequelae of health insults experienced during childhood development.
RESUMO
Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) are a significant health concern, exacerbated by the rapid emergence of multidrug resistant strains refractory to antibiotic treatment. P fimbriae are strongly associated with upper urinary tract colonization due to specific binding to α-D-galactopyranosyl-(1-4)-ß-D-galactopyranoside receptors in the kidneys. Thus, inhibiting P-fimbrial adhesion may reduce the incidence of UPEC-mediated UTI. E. coli 83972 is an asymptomatic bacteriuria isolate successfully used as a prophylactic agent to prevent UTI in human studies. We constructed a recombinant E. coli 83972 strain displaying a surface-located oligosaccharide P fimbriae receptor mimic that bound to P-fimbriated E. coli producing any of the 3 PapG adhesin variants. The recombinant strain, E. coli 83972::lgtCE, impaired P fimbriae-mediated adhesion to human erythrocytes and kidney epithelial cells. Additionally, E. coli 83972::lgtCE impaired urine colonization by UPEC in a mouse UTI model, demonstrating its potential as a prophylactic agent to prevent UTI.
Assuntos
Aderência Bacteriana , Proteínas de Fímbrias/metabolismo , Oligossacarídeos/metabolismo , Escherichia coli Uropatogênica/patogenicidade , Animais , Modelos Animais de Doenças , Células Epiteliais/microbiologia , Eritrócitos/microbiologia , Feminino , Proteínas de Fímbrias/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Oligossacarídeos/genética , Ligação Proteica , Infecções Urinárias/prevenção & controle , Escherichia coli Uropatogênica/genéticaRESUMO
The molecular mechanisms that define asymptomatic bacteriuria (ABU) Escherichia coli colonization of the human urinary tract remain to be properly elucidated. Here, we utilize ABU E. coli strain 83972 as a model to dissect the contribution of siderophores to iron acquisition, growth, fitness, and colonization of the urinary tract. We show that E. coli 83972 produces enterobactin, salmochelin, aerobactin, and yersiniabactin and examine the role of these systems using mutants defective in siderophore biosynthesis and uptake. Enterobactin and aerobactin contributed most to total siderophore activity and growth in defined iron-deficient medium. No siderophores were detected in an 83972 quadruple mutant deficient in all four siderophore biosynthesis pathways; this mutant did not grow in defined iron-deficient medium but grew in iron-limited pooled human urine due to iron uptake via the FecA ferric citrate receptor. In a mixed 1:1 growth assay with strain 83972, there was no fitness disadvantage of the 83972 quadruple biosynthetic mutant, demonstrating its capacity to act as a "cheater" and utilize siderophores produced by the wild-type strain for iron uptake. An 83972 enterobactin/salmochelin double receptor mutant was outcompeted by 83972 in human urine and the mouse urinary tract, indicating a role for catecholate receptors in urinary tract colonization.
Assuntos
Bacteriúria/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/metabolismo , Escherichia coli/patogenicidade , Sideróforos/metabolismo , Infecções Urinárias/microbiologia , Fatores de Virulência/metabolismo , Animais , Meios de Cultura/química , Feminino , Deleção de Genes , Humanos , Ferro/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Sideróforos/genética , Sistema Urinário/microbiologia , Urina/microbiologia , Fatores de Virulência/genéticaRESUMO
The natural killer (NK) type of aggressive large granular lymphocytic (LGL) leukemia is a fatal illness that pursues a rapid clinical course. There are no effective therapies for this illness, and pathogenetic mechanisms remain undefined. Here we report that the survivin was highly expressed in both aggressive and chronic leukemic NK cells but not in normal NK cells. In vitro treatment of human and rat NK-LGL leukemia cells with cell-permeable, short-chain C6-ceramide (C6) in nanoliposomal formulation led to caspase-dependent apoptosis and diminished survivin protein expression, in a time- and dose-dependent manner. Importantly, systemic intravenous delivery of nanoliposomal ceramide induced complete remission in the syngeneic Fischer F344 rat model of aggressive NK-LGL leukemia. Therapeutic efficacy was associated with decreased expression of survivin in vivo. These data suggest that in vivo targeting of survivin through delivery of nanoliposomal C6-ceramide may be a promising therapeutic approach for a fatal leukemia.
Assuntos
Ceramidas/farmacologia , Leucemia Linfocítica Granular Grande/terapia , Lipossomos/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Nanopartículas/química , Animais , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Ceramidas/uso terapêutico , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Humanos , Leucemia Linfocítica Granular Grande/tratamento farmacológico , Leucemia Linfocítica Granular Grande/enzimologia , Leucemia Linfocítica Granular Grande/patologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/patologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Ratos , Ratos Endogâmicos F344 , Indução de Remissão , Survivina , Resultado do TratamentoRESUMO
Urinary tract infections (UTIs) are among the most common infectious diseases of humans, with Escherichia coli being responsible for >80% of all cases. Asymptomatic bacteriuria (ABU) occurs when bacteria colonize the urinary tract without causing clinical symptoms and can affect both catheterized patients (catheter-associated ABU [CA-ABU]) and noncatheterized patients. Here, we compared the virulence properties of a collection of ABU and CA-ABU nosocomial E. coli isolates in terms of antibiotic resistance, phylogenetic grouping, specific UTI-associated virulence genes, hemagglutination characteristics, and biofilm formation. CA-ABU isolates were similar to ABU isolates with regard to the majority of these characteristics; exceptions were that CA-ABU isolates had a higher prevalence of the polysaccharide capsule marker genes kpsMT II and kpsMT K1, while more ABU strains were capable of mannose-resistant hemagglutination. To examine biofilm growth in detail, we performed a global gene expression analysis with two CA-ABU strains that formed a strong biofilm and that possessed a limited adhesin repertoire. The gene expression profile of the CA-ABU strains during biofilm growth showed considerable overlap with that previously described for the prototype ABU E. coli strain, 83972. This is the first global gene expression analysis of E. coli CA-ABU strains. Overall, our data suggest that nosocomial ABU and CA-ABU E. coli isolates possess similar virulence profiles.
Assuntos
Bacteriúria/microbiologia , Escherichia coli , Cateterismo Urinário , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biofilmes , Cateteres de Demora/microbiologia , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/patogenicidade , Feminino , Perfilação da Expressão Gênica , Genes Bacterianos , Humanos , Ferro/metabolismo , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Filogenia , Fatores de Virulência/genética , Resistência beta-Lactâmica/genéticaRESUMO
Melanoma is a progressive disease that claims many lives each year due to lack of therapeutics effective for the long-term treatment of patients. Currently, the best treatment option is early detection followed by surgical removal. Better melanoma therapies that are effectively delivered to tumors with minimal toxicity for patients are urgently needed. Nanotechnologies provide one approach to encapsulate therapeutic agents leading to improvements in circulation time, enhanced tumor uptake, avoidance of the reticulo-endothelial system, and minimization of toxicity. Liposomes in particular are a promising nanotechnology that can be used for more effective delivery of therapeutic agents to treat melanoma. Liposomes delivering chemotherapies, siRNA, asODNs, DNA, and radioactive particles are just some of the promising new nanotechnology based therapies under development for the treatment of melanoma that are discussed in this review.
Assuntos
Antineoplásicos/administração & dosagem , Lipossomos , Melanoma/terapia , Neoplasias Cutâneas/terapia , Antineoplásicos/uso terapêutico , Composição de Medicamentos , Terapia Genética , Humanos , Melanoma/tratamento farmacológico , Nanoestruturas , Ácidos Nucleicos/administração & dosagem , Ácidos Nucleicos/uso terapêutico , Neoplasias Cutâneas/tratamento farmacológicoRESUMO
In asymptomatic bacteriuria (ABU), bacteria colonize the urinary tract without provoking symptoms. Here, we compared the virulence properties of a collection of ABU Escherichia coli strains to cystitis and pyelonephritis strains. Specific urinary tract infection (UTI)-associated virulence genes, hemagglutination characteristics, siderophore production, hemolysis, biofilm formation, and the ability of strains to adhere to and induce cytokine responses in epithelial cells were analyzed. ABU strains were phylogenetically related to strains that cause symptomatic UTI. However, the virulence properties of the ABU strains were variable and dependent on a combination of genotypic and phenotypic factors. Most ABU strains adhered poorly to epithelial cells; however, we also identified a subgroup of strongly adherent strains that were unable to stimulate an epithelial cell IL-6 cytokine response. Poor immune activation may represent one mechanism whereby ABU E. coli evade immune detection after the establishment of bacteriuria.