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The highly conserved and essential Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) has emerged as the leading target for vaccines against the disease-causing blood stage of malaria. However, the features of the human vaccine-induced antibody response that confer highly potent inhibition of malaria parasite invasion into red blood cells are not well defined. Here, we characterize 236 human IgG monoclonal antibodies, derived from 15 donors, induced by the most advanced PfRH5 vaccine. We define the antigenic landscape of this molecule and establish that epitope specificity, antibody association rate, and intra-PfRH5 antibody interactions are key determinants of functional anti-parasitic potency. In addition, we identify a germline IgG gene combination that results in an exceptionally potent class of antibody and demonstrate its prophylactic potential to protect against P. falciparum parasite challenge in vivo. This comprehensive dataset provides a framework to guide rational design of next-generation vaccines and prophylactic antibodies to protect against blood-stage malaria.
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Pfs230 is essential for Plasmodium falciparum transmission to mosquitoes and is the protein targeted by the most advanced malaria-transmission-blocking vaccine candidate. Prior understanding of functional epitopes on Pfs230 is based on two monoclonal antibodies (mAbs) with moderate transmission-reducing activity (TRA), elicited from subunit immunization. Here, we screened the B cell repertoire of two naturally exposed individuals possessing serum TRA and identified five potent mAbs from sixteen Pfs230 domain-1-specific mAbs. Structures of three potent and three low-activity antibodies bound to Pfs230 domain 1 revealed four distinct epitopes. Highly potent mAbs from natural infection recognized a common conformational epitope that is highly conserved across P. falciparum field isolates, while antibodies with negligible TRA derived from natural infection or immunization recognized three distinct sites. Our study provides molecular blueprints describing P. falciparum TRA, informed by contrasting potent and non-functional epitopes elicited by natural exposure and vaccination.
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Vacunas contra la Malaria , Malaria Falciparum , Humanos , Animales , Plasmodium falciparum , Epítopos , Proteínas Protozoarias , Antígenos de Protozoos , Anticuerpos Monoclonales , Anticuerpos Antiprotozoarios , Malaria Falciparum/prevención & controlRESUMEN
Malaria transmission-blocking vaccines (TBVs) aim to induce antibodies that interrupt malaria parasite development in the mosquito, thereby blocking onward transmission, and provide a much-needed tool for malaria control and elimination. The parasite surface protein Pfs48/45 is a leading TBV candidate. Here, we isolated and characterized a panel of 81 human Pfs48/45-specific monoclonal antibodies (mAbs) from donors naturally exposed to Plasmodium parasites. Genetically diverse mAbs against each of the three domains (D1-D3) of Pfs48/45 were identified. The most potent mAbs targeted D1 and D3 and achieved >80% transmission-reducing activity in standard membrane-feeding assays, at 10 and 2 µg/mL, respectively. Co-crystal structures of D3 in complex with four different mAbs delineated two conserved protective epitopes. Altogether, these Pfs48/45-specific human mAbs provide important insight into protective and non-protective epitopes that can further our understanding of transmission and inform the design of refined malaria transmission-blocking vaccine candidates.
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Culicidae , Vacunas contra la Malaria , Malaria Falciparum , Malaria , Animales , Humanos , Plasmodium falciparum , Culicidae/metabolismo , Proteínas Protozoarias , Anticuerpos Monoclonales , Malaria Falciparum/prevención & control , Anticuerpos AntiprotozoariosRESUMEN
Malaria transmission-blocking vaccines (TBVs) aim to elicit human antibodies that inhibit sporogonic development of Plasmodium falciparum in mosquitoes, thereby preventing onward transmission. Pfs48/45 is a leading clinical TBV candidate antigen and is recognized by the most potent transmission-blocking monoclonal antibody (mAb) yet described; still, clinical development of Pfs48/45 antigens has been hindered, largely by its poor biochemical characteristics. Here, we used structure-based computational approaches to design Pfs48/45 antigens stabilized in the conformation recognized by the most potently inhibitory mAb, achieving >25°C higher thermostability compared with the wild-type protein. Antibodies elicited in mice immunized with these engineered antigens displayed on liposome-based or protein nanoparticle-based vaccine platforms exhibited 1-2 orders of magnitude superior transmission-reducing activity, compared with immunogens bearing the wild-type antigen, driven by improved antibody quality. Our data provide the founding principles for using molecular stabilization solely from antibody structure-function information to drive improved immune responses against a parasitic vaccine target.
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Vacunas contra la Malaria , Malaria Falciparum , Animales , Anticuerpos Bloqueadores , Anticuerpos Monoclonales , Anticuerpos Antiprotozoarios , Formación de Anticuerpos , Antígenos de Protozoos , Humanos , Malaria Falciparum/prevención & control , Glicoproteínas de Membrana , Ratones , Plasmodium falciparum , Proteínas Protozoarias , VacunaciónRESUMEN
Human epithelial tissues accumulate cancer-driver mutations with age1-9, yet tumour formation remains rare. The positive selection of these mutations suggests that they alter the behaviour and fitness of proliferating cells10-12. Thus, normal adult tissues become a patchwork of mutant clones competing for space and survival, with the fittest clones expanding by eliminating their less competitive neighbours11-14. However, little is known about how such dynamic competition in normal epithelia influences early tumorigenesis. Here we show that the majority of newly formed oesophageal tumours are eliminated through competition with mutant clones in the adjacent normal epithelium. We followed the fate of nascent, microscopic, pre-malignant tumours in a mouse model of oesophageal carcinogenesis and found that most were rapidly lost with no indication of tumour cell death, decreased proliferation or an anti-tumour immune response. However, deep sequencing of ten-day-old and one-year-old tumours showed evidence of selection on the surviving neoplasms. Induction of highly competitive clones in transgenic mice increased early tumour removal, whereas pharmacological inhibition of clonal competition reduced tumour loss. These results support a model in which survival of early neoplasms depends on their competitive fitness relative to that of mutant clones in the surrounding normal tissue. Mutant clones in normal epithelium have an unexpected anti-tumorigenic role in purging early tumours through cell competition, thereby preserving tissue integrity.
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Competencia Celular , Proliferación Celular , Células Clonales/citología , Células Clonales/metabolismo , Células Epiteliales/citología , Neoplasias Esofágicas/patología , Mutación , Animales , Carcinogénesis/inmunología , Muerte Celular , Supervivencia Celular , Modelos Animales de Enfermedad , Células Epiteliales/inmunología , Células Epiteliales/patología , Epitelio/inmunología , Neoplasias Esofágicas/inmunología , Femenino , Masculino , Ratones , Factores de TiempoRESUMEN
Mechanophores are molecular motifs that respond to mechanical perturbance with targeted chemical reactions toward desirable changes in material properties. A large variety of mechanophores have been investigated, with applications focusing on functional materials, such as strain/stress sensors, nanolithography, and self-healing polymers, among others. The responses of engineered mechanophores, such as light emittance, change in fluorescence, and generation of free radicals (FRs), have potential for bioimaging and therapy. However, the biomedical applications of mechanophores are not well explored. Herein, we report an in vitro demonstration of an FR-generating mechanophore embedded in biocompatible hydrogels for noninvasive cancer therapy. Controlled by high-intensity focused ultrasound (HIFU), a clinically proven therapeutic technique, mechanophores were activated with spatiotemporal precision to generate FRs that converted to reactive oxygen species (ROS) to effectively kill tumor cells. The mechanophore hydrogels exhibited no cytotoxicity under physiological conditions. Upon activation with HIFU sonication, the therapeutic efficacies in killing in vitro murine melanoma and breast cancer tumor cells were comparable with lethal doses of H2O2 This process demonstrated the potential for mechanophore-integrated HIFU combination as a noninvasive cancer treatment platform, named "mechanochemical dynamic therapy" (MDT). MDT has two distinct advantages over other noninvasive cancer treatments, such as photodynamic therapy (PDT) and sonodynamic therapy (SDT). 1) MDT is ultrasound based, with larger penetration depth than PDT. 2) MDT does not rely on sonosensitizers or the acoustic cavitation effect, both of which are necessary for SDT. Taking advantage of the strengths of mechanophores and HIFU, MDT can provide noninvasive treatments for diverse cancer types.
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Fenómenos Biomecánicos , Biopolímeros/química , Hidrogeles/química , Ondas Ultrasónicas , Animales , Compuestos Azo/química , Humanos , Hidrogeles/síntesis química , Melanoma Experimental , Ratones , Neoplasias/terapia , Polietilenglicoles/química , Especies Reactivas de Oxígeno/química , Especies Reactivas de Oxígeno/metabolismo , Termodinámica , Terapia por Ultrasonido/métodosRESUMEN
Both neuronal and genetic mechanisms regulate brain function. While there are excellent methods to study neuronal activity in vivo, there are no nondestructive methods to measure global gene expression in living brains. Here, we present a method, epigenetic MRI (eMRI), that overcomes this limitation via direct imaging of DNA methylation, a major gene-expression regulator. eMRI exploits the methionine metabolic pathways for DNA methylation to label genomic DNA through 13C-enriched diets. A 13C magnetic resonance spectroscopic imaging method then maps the spatial distribution of labeled DNA. We validated eMRI using pigs, whose brains have stronger similarity to humans in volume and anatomy than rodents, and confirmed efficient 13C-labeling of brain DNA. We also discovered strong regional differences in global DNA methylation. Just as functional MRI measurements of regional neuronal activity have had a transformational effect on neuroscience, we expect that the eMRI signal, both as a measure of regional epigenetic activity and as a possible surrogate for regional gene expression, will enable many new investigations of human brain function, behavior, and disease.
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Encéfalo/metabolismo , Metilación de ADN , Epigénesis Genética , Imagen por Resonancia Magnética/métodos , Animales , Encéfalo/diagnóstico por imagen , Isótopos de Carbono/metabolismo , Espectroscopía de Resonancia Magnética con Carbono-13 , Humanos , Metionina/administración & dosificación , Reproducibilidad de los Resultados , PorcinosRESUMEN
Potent and durable vaccine responses will be required for control of malaria caused by Plasmodium falciparum (Pf). RTS,S/AS01 is the first, and to date, the only vaccine that has demonstrated significant reduction of clinical and severe malaria in endemic cohorts in Phase 3 trials. Although the vaccine is protective, efficacy declines over time with kinetics paralleling the decline in antibody responses to the Pf circumsporozoite protein (PfCSP). Although most attention has focused on antibodies to repeat motifs on PfCSP, antibodies to other regions may play a role in protection. Here, we expressed and characterized seven monoclonal antibodies to the C-terminal domain of CSP (ctCSP) from volunteers immunized with RTS,S/AS01. Competition and crystal structure studies indicated that the antibodies target two different sites on opposite faces of ctCSP. One site contains a polymorphic region (denoted α-ctCSP) and has been previously characterized, whereas the second is a previously undescribed site on the conserved ß-sheet face of the ctCSP (denoted ß-ctCSP). Antibodies to the ß-ctCSP site exhibited broad reactivity with a diverse panel of ctCSP peptides whose sequences were derived from field isolates of P. falciparum whereas antibodies to the α-ctCSP site showed very limited cross reactivity. Importantly, an antibody to the ß-site demonstrated inhibition activity against malaria infection in a murine model. This study identifies a previously unidentified conserved epitope on CSP that could be targeted by prophylactic antibodies and exploited in structure-based vaccine design.
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Vacunas contra la Malaria , Malaria Falciparum , Malaria , Animales , Anticuerpos Antiprotozoarios , Epítopos , Humanos , Malaria Falciparum/prevención & control , Ratones , Plasmodium falciparum , Proteínas Protozoarias/genéticaRESUMEN
Over 60 years ago, stone tools and remains of megafauna were discovered on the Southeast Asian islands of Flores, Sulawesi and Luzon, and a Middle Pleistocene colonization by Homo erectus was initially proposed to have occurred on these islands1-4. However, until the discovery of Homo floresiensis in 2003, claims of the presence of archaic hominins on Wallacean islands were hypothetical owing to the absence of in situ fossils and/or stone artefacts that were excavated from well-documented stratigraphic contexts, or because secure numerical dating methods of these sites were lacking. As a consequence, these claims were generally treated with scepticism 5 . Here we describe the results of recent excavations at Kalinga in the Cagayan Valley of northern Luzon in the Philippines that have yielded 57 stone tools associated with an almost-complete disarticulated skeleton of Rhinoceros philippinensis, which shows clear signs of butchery, together with other fossil fauna remains attributed to stegodon, Philippine brown deer, freshwater turtle and monitor lizard. All finds originate from a clay-rich bone bed that was dated to between 777 and 631 thousand years ago using electron-spin resonance methods that were applied to tooth enamel and fluvial quartz. This evidence pushes back the proven period of colonization 6 of the Philippines by hundreds of thousands of years, and furthermore suggests that early overseas dispersal in Island South East Asia by premodern hominins took place several times during the Early and Middle Pleistocene stages1-4. The Philippines therefore may have had a central role in southward movements into Wallacea, not only of Pleistocene megafauna 7 , but also of archaic hominins.
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Fósiles , Hominidae , Comportamiento del Uso de la Herramienta , Silicatos de Aluminio , Migración Animal , Animales , Arcilla , Espectroscopía de Resonancia por Spin del Electrón , Sedimentos Geológicos , Historia Antigua , Filipinas , Datación RadiométricaRESUMEN
OBJECTIVES: To determine the relationship between food insecurity and periodontitis among adults in the United States (US). METHODS: Secondary analysis of the 2009-2014 National Health and Nutrition Examination Survey data. The sample included 6,108 US participants aged ≥ 30 years in a probability weighted sample. Periodontitis status was measured in full-month oral examinations at 6 sites per tooth for clinical attachment loss and periodontal probing depth. Food insecurity was assessed by the 18-item US Food Security Survey Module. RESULTS: Controlling for covariates, multiple logistic regression showed that periodontitis was associated with low food security (adjusted odds ratio (aOR)=1.30, 95% CI: 1.08-1.57). Risk factors for periodontitis included HbA1c ≥ 7% (aOR=1.74, 95% CI: 1.26-2.40), seeking emergency dental care (aOR=1.36, 95% CI:1.19-1.55), smoking status, racial minorities, low income, and older age. Protective factors for periodontitis were annual dental visit (aOR=0.52, 95% CI: 0.43-0.64), health insurance (aOR=0.66, 95% CI: 0.54-0.80), female gender, and college education. CONCLUSIONS: Food insecurity was associated with a higher risk of periodontitis among US adults. Having enough food to eat is a basic human right and would improve well-being.
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Preprocessing fMRI data requires striking a fine balance between conserving signals of interest and removing noise. Typical steps of preprocessing include motion correction, slice timing correction, spatial smoothing, and high-pass filtering. However, these standard steps do not remove many sources of noise. Thus, noise-reduction techniques, for example, CompCor, FIX, and ICA-AROMA have been developed to further improve the ability to draw meaningful conclusions from the data. The ability of these techniques to minimize noise while conserving signals of interest has been tested almost exclusively in resting-state fMRI and, only rarely, in task-related fMRI. Application of noise-reduction techniques to task-related fMRI is particularly important given that such procedures have been shown to reduce false positive rates. Little remains known about the impact of these techniques on the retention of signal in tasks that may be associated with systemic physiological changes. In this paper, we compared two ICA-based, that is FIX and ICA-AROMA, two CompCor-based noise-reduction techniques, that is aCompCor, and tCompCor, and standard preprocessing using a large (n = 101) fMRI dataset including noxious heat and non-noxious auditory stimulation. Results show that preprocessing using FIX performs optimally for data obtained using noxious heat, conserving more signals than CompCor-based techniques and ICA-AROMA, while removing only slightly less noise. Similarly, for data obtained during non-noxious auditory stimulation, FIX noise-reduction technique before analysis with a covariate of interest outperforms the other techniques. These results indicate that FIX might be the most appropriate technique to achieve the balance between conserving signals of interest and removing noise during task-related fMRI.
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Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Artefactos , Análisis de Componente Principal , Movimiento (Física) , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Mapeo Encefálico/métodosRESUMEN
BACKGROUND: Mobile technology offers unique opportunities for monitoring short-term suicide risk in daily life. In this study of suicidal adolescent inpatients, theoretically informed risk factors were assessed daily following discharge to predict near-term suicidal ideation and inform decision algorithms for identifying elevations in daily level risk, with implications for real-time suicide-focused interventions. METHODS: Adolescents (N = 78; 67.9% female) completed brief surveys texted daily for 4 weeks after discharge (n = 1621 observations). Using multi-level classification and regression trees (CARTSs) with repeated 5-fold cross-validation, we tested (a) a simple prediction model incorporating previous-day scores for each of 10 risk factors, and (b) a more complex model incorporating, for each of these factors, a time-varying person-specific mean over prior days together with deviation from that mean. Models also incorporated missingness and contextual (study week, day of the week) indicators. The outcome was the presence/absence of next-day suicidal ideation. RESULTS: The best-performing model (cross-validated AUC = 0.86) was a complex model that included ideation duration, hopelessness, burdensomeness, and self-efficacy to refrain from suicidal action. An equivalent model that excluded ideation duration had acceptable overall performance (cross-validated AUC = 0.78). Models incorporating only previous-day scores, with and without ideation duration (cross-validated AUC of 0.82 and 0.75, respectively), showed relatively weaker performance. CONCLUSIONS: Results suggest that specific combinations of dynamic risk factors assessed in adolescents' daily life have promising utility in predicting next-day suicidal thoughts. Findings represent an important step in the development of decision tools identifying short-term risk as well as guiding timely interventions sensitive to proximal elevations in suicide risk in daily life.
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Ideación Suicida , Suicidio , Humanos , Adolescente , Hospitalización , Alta del Paciente , Factores de Riesgo , Aprendizaje AutomáticoRESUMEN
BACKGROUND: Concerns have been raised about the utility of self-report assessments in predicting future suicide attempts. Clinicians in pediatric emergency departments (EDs) often are required to assess suicidal risk. The Death Implicit Association Test (IAT) is an alternative to self-report assessment of suicidal risk that may have utility in ED settings. METHODS: A total of 1679 adolescents recruited from 13 pediatric emergency rooms in the Pediatric Emergency Care Applied Research Network were assessed using a self-report survey of risk and protective factors for a suicide attempt, and the IAT, and then followed up 3 months later to determine if an attempt had occurred. The accuracy of prediction was compared between self-reports and the IAT using the area under the curve (AUC) with respect to receiver operator characteristics. RESULTS: A few self-report variables, namely, current and past suicide ideation, past suicidal behavior, total negative life events, and school or social connectedness, predicted an attempt at 3 months with an AUC of 0.87 [95% confidence interval (CI), 0.84-0.90] in the entire sample, and AUC = 0.91, (95% CI 0.85-0.95) for those who presented without reported suicidal ideation. The IAT did not add significantly to the predictive power of selected self-report variables. The IAT alone was modestly predictive of 3-month attempts in the overall sample ((AUC = 0.59, 95% CI 0.52-0.65) and was a better predictor in patients who were non-suicidal at baseline (AUC = 0.67, 95% CI 0.55-0.79). CONCLUSIONS: In pediatric EDs, a small set of self-reported items predicted suicide attempts within 3 months more accurately than did the IAT.
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Ideación Suicida , Intento de Suicidio , Humanos , Adolescente , Niño , Autoinforme , Factores Protectores , Medición de Riesgo/métodos , Servicio de Urgencia en Hospital , Factores de RiesgoRESUMEN
Shape stability is key to avoiding degradation of performance for metallic nanocrystals synthesized with facetted non-equilibrium shapes to optimize properties for catalysis, plasmonics, and so on. Reshaping of facetted nanocrystals is controlled by the surface diffusion-mediated nucleation and growth of new outer layers of atoms. Kinetic Monte Carlo (KMC) simulation of a realistic stochastic atomistic-level model is applied to precisely track the reshaping of Pd octahedra and nanocubes. Unexpectedly, separate constrained equilibrium Monte Carlo analysis of the free energy profile during reshaping reveals a fundamental failure of the classical nucleation theory (CNT) prediction for the reshaping barrier and rate. Why? Nucleation barriers can be relatively low for these processes, so the system is not locally equilibrated before crossing the barrier, as assumed in CNT. This claim is supported by an analysis of a first-passage problem for reshaping within a master equation framework for the model that reasonably captures the behavior in KMC simulations.
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Detecting metal ions in vivo with a high spatiotemporal resolution is critical to understanding the roles of the metal ions in both healthy and disease states. Although spatiotemporal controls of metal-ion sensors using light have been demonstrated, the lack of penetration depth in tissue and in vivo has limited their application. To overcome this limitation, we herein report the use of high-intensity focused ultrasound (HIFU) to remotely deliver on-demand, spatiotemporally resolved thermal energy to activate the DNAzyme sensors at the targeted region both in vitro and in vivo. A Zn2+-selective DNAzyme probe is inactivated by a protector strand to block the formation of catalytic enzyme structure, which can then be activated by an HIFU-induced increase in the local temperature. With this design, Zn2+-specific fluorescent resonance energy transfer (FRET) imaging has been demonstrated by the new DNAzyme-HIFU probes in both HeLa cells and mice. The current method can be applied to monitor many other metal ions for in vivo imaging and medical diagnosis using metal-specific DNAzymes that have either been obtained or can be selected using in vitro selection.
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ADN Catalítico , Animales , ADN Catalítico/química , Transferencia de Energía , Células HeLa , Humanos , Iones , Metales/química , RatonesRESUMEN
Lasting protection has long been a goal for malaria vaccines. The major surface antigen on Plasmodium falciparum sporozoites, the circumsporozoite protein (PfCSP), has been an attractive target for vaccine development and most protective antibodies studied to date interact with the central NANP repeat region of PfCSP. However, it remains unclear what structural and functional characteristics correlate with better protection by one antibody over another. Binding to the junctional region between the N-terminal domain and central NANP repeats has been proposed to result in superior protection: this region initiates with the only NPDP sequence followed immediately by NANP. Here, we isolated antibodies in Kymab mice immunized with full-length recombinant PfCSP and two protective antibodies were selected for further study with reactivity against the junctional region. X-ray and EM structures of two monoclonal antibodies, mAb667 and mAb668, shed light on their differential affinity and specificity for the junctional region. Importantly, these antibodies also bind to the NANP repeat region with equal or better affinity. A comparison with an NANP-only binding antibody (mAb317) revealed roughly similar but statistically distinct levels of protection against sporozoite challenge in mouse liver burden models, suggesting that junctional antibody protection might relate to the ability to also cross-react with the NANP repeat region. Our findings indicate that additional efforts are necessary to isolate a true junctional antibody with no or much reduced affinity to the NANP region to elucidate the role of the junctional epitope in protection.
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Anticuerpos Monoclonales de Origen Murino/química , Anticuerpos Antiprotozoarios/química , Sitios de Unión de Anticuerpos , Epítopos/química , Plasmodium falciparum/química , Proteínas Protozoarias/química , Animales , Anticuerpos Monoclonales de Origen Murino/inmunología , Anticuerpos Antiprotozoarios/inmunología , Epítopos/inmunología , Femenino , Masculino , Ratones , Ratones Transgénicos , Plasmodium falciparum/inmunología , Proteínas Protozoarias/inmunología , Relación Estructura-ActividadRESUMEN
While study in the field of polymer mechanochemistry has yielded mechanophores that perform various chemical reactions in response to mechanical stimuli, there is not yet a triggering method compatible with biological systems. Applications such as using mechanoluminescence to generate localized photon flux in vivo for optogenetics would greatly benefit from such an approach. Here we introduce a method of triggering mechanophores by using high-intensity focused ultrasound (HIFU) as a remote energy source to drive the spatially and temporally resolved mechanical-to-chemical transduction of mechanoresponsive polymers. A HIFU setup capable of controlling the excitation pressure, spatial location, and duration of exposure is employed to activate mechanochemical reactions in a cross-linked elastomeric polymer in a noninvasive fashion. One reaction is the chromogenic isomerization of a naphthopyran mechanophore embedded in a polydimethylsiloxane (PDMS) network. Under HIFU irradiation evidence of the mechanochemical transduction is the observation of a reversible color change as expected for the isomerization. The elastomer exhibits this distinguishable color change at the focal spot, depending on ultrasonic exposure conditions. A second reaction is the demonstration that HIFU irradiation successfully triggers a luminescent dioxetane, resulting in localized generation of visible blue light at the focal spot. In contrast to conventional stimuli such as UV light, heat, and uniaxial compression/tension testing, HIFU irradiation provides spatiotemporal control of the mechanochemical activation through targeted but noninvasive ultrasonic energy deposition. Targeted, remote light generation is potentially useful in biomedical applications such as optogenetics where a light source is used to trigger a cellular response.
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Elastómeros/química , Ultrasonido Enfocado de Alta Intensidad de Ablación/métodos , Luz , Ultrasonido/métodosRESUMEN
Internal teat sealants (ITS) reduce the risk of new intramammary infections over the dry period by forming a physical barrier to pathogen ingress. As the first and last 2 wk of the dry period are high-risk periods for new infections, maintaining an effective barrier in this period is a key requirement. Few studies have systematically examined sealant retention and none have done so under New Zealand pastoral conditions, where cows frequently move to separate grazing for dry periods, typically 80 to 90 d long. This multi-herd study was a split-udder equivalence trial comparing 2 ITS formulations for retention and efficacy in preventing periparturient clinical and subclinical mastitis. Both ITS contained 65% (2.6 g) bismuth salts, which contribute to the barrier within the teat canal, emulsified in ≤1.4 g of mineral oil. However, one ITS additionally contained <10% amorphous silica. At dry-off, treatment was randomly allocated to diagonal teat-pairs within 409 cows on 4 farms. All cows met industry best practice criteria for ITS treatment alone. The study unit was quarter within cow and farm. Outcomes included clinical mastitis (CM) incidence for the last 7 d of the dry period and first 42 d of lactation, subclinical mastitis (SCM) incidence 96 h after calving, and quantity of residual after centrifuging 50 mL of colostrum collected from each quarter within 24 h of calving. Proportional outcomes were analyzed using Bayesian mixed models with a binomial distribution and logit link function, whereas the quantity of residual was analyzed using Bayesian finite mixture models and cluster bootstrapping. We set a region of probable equivalence (ROPE) of ±2.5% between proportions and ±0.2 g for residual weight. Records were available for 1,596 quarters (399 cows). We detected no meaningful difference in incidence of CM or SCM attributable to differences in sealant: the model predicted treatment differences of 0.00 with a 95% highest density interval (HDI) of ±1.00%. Across all cows and farms, the marginal difference in the percentage of quarters with CM was 0.11% (95% HDI: -2.11 to 2.49%), and for SCM 0.00 (95% HDI: -1.98 to 1.94%). Including the quantity of residual recovered at calving did not improve fit or predictive ability of the models predicting CM or SCM, and the coefficient spanned the null value. The distribution of the weight of material recovered at calving was multi-modal; for 25% of quarters, more residual was recovered than inserted. When the residual weight was less than or equal to the median residual weight (2.06 g; range: 0.19-6.03 g), there was a ≥90% probability that any treatment difference in residual was ≤0.2 g. When the residual weight was between the median and 75th percentile (4.40 g; 95% HDI: 4.00 to 4.75 g), there was no clear difference in residual between products. Above the 75th percentile, there was a 90% probability that the residual from quarters differed by product type (difference = 0.36 g, 90% HDI: 0.20 to 0.54 g). In conclusion, both products had equivalent efficacy for SCM and CM. As the quantity of residual increased, the difference in residual weight recovered increased but this may represent increases in debris rather than indicating a more effective barrier.
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Enfermedades de los Bovinos , Mastitis Bovina , Animales , Antibacterianos/uso terapéutico , Teorema de Bayes , Bovinos , Enfermedades de los Bovinos/tratamiento farmacológico , Femenino , Lactancia , Glándulas Mamarias Animales , Mastitis Bovina/epidemiología , LecheRESUMEN
The aim of this study was to explore provider practices and attitudes towards routine follow-up counselling after prescription of contraceptives. An anonymous 16-item survey was pilot-tested and sent to providers of the Internal Medicine, Family Medicine, Pediatrics, and OBGYN departments of Thomas Jefferson University Hospitals (TJUH), an urban academic medical centre in Philadelphia, PA, USA. Frequency and descriptive statistics were used to analyse quantitative data while a framework analysis approach was applied to open-ended questions. Fifty percent of providers said they typically follow up with patients regarding a newly prescribed contraceptive. Only 15.3% said they do for an existing prescription. Eighty-three percent reported that it is important though only 30% believed follow-up guidelines were clear. Ultimately, there is a gap between providers' interest in delivering follow-up care and established direction on how to do so.Impact StatementWhat is already known on the subject? Prescription contraceptive adherence is suboptimal. However, it is known that proactive follow-up has positive effects on prescription contraceptive adherence.What do the results of the study add? Most respondents believe that patients take their prescription contraception as prescribed. In light of this finding, providers are less likely to follow up with an existing prescription contraceptive. Interestingly, most respondents do believe that follow-up is important for patients using prescribed contraception but endorse that guidelines about follow-up are neither established nor clear.What are the implications of these findings for clinical practice and/or further research? Patient adherence to prescription contraceptives can be improved through optimised routine patient follow-up after initial prescription. This must be done in ways that minimise burdens to both patients and providers. Providers could benefit from clear guidelines regarding best practices. Future research is needed to understand how providers can best support patients on their contraceptive journey.
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Actitud del Personal de Salud , Continuidad de la Atención al Paciente , Anticoncepción , Prescripciones , Niño , Femenino , Humanos , Actitud , Anticoncepción/métodos , Anticonceptivos Orales , Conocimientos, Actitudes y Práctica en SaludRESUMEN
The Plasmodium falciparum circumsporozoite protein (PfCSP) is a sporozoite surface protein whose role in sporozoite motility and cell invasion has made it the leading candidate for a pre-erythrocytic malaria vaccine. However, production of high yields of soluble recombinant PfCSP, including its extensive NANP and NVDP repeats, has proven problematic. Here, we report on the development and characterization of a secreted, soluble, and stable full-length PfCSP (containing 4 NVDP and 38 NANP repeats) produced in the Lactococcus lactis expression system. The recombinant full-length PfCSP, denoted PfCSP4/38, was produced initially with a histidine tag and purified by a simple two-step procedure. Importantly, the recombinant PfCSP4/38 retained a conformational epitope for antibodies as confirmed by both in vivo and in vitro characterizations. We characterized this complex protein by HPLC, light scattering, MS analysis, differential scanning fluorimetry, CD, SDS-PAGE, and immunoblotting with conformation-dependent and -independent mAbs, which confirmed it to be both pure and soluble. Moreover, we found that the recombinant protein is stable at both frozen and elevated-temperature storage conditions. When we used L. lactis-derived PfCSP4/38 to immunize mice, it elicited high levels of functional antibodies that had the capacity to modify sporozoite motility in vitro We concluded that the reported yield, purity, results of biophysical analyses, and stability of PfCSP4/38 warrant further consideration of using the L. lactis system for the production of circumsporozoite proteins for preclinical and clinical applications in malaria vaccine development.