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1.
J Hered ; 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38814752

RESUMEN

Small, fragmented or isolated populations are at risk of population decline due to fitness costs associated with inbreeding and genetic drift. The King Island scrubtit Acanthornis magna greeniana is a critically endangered subspecies of the nominate Tasmanian scrubtit A. m. magna, with an estimated population of < 100 individuals persisting in three patches of swamp forest. The Tasmanian scrubtit is widespread in wet forests on mainland Tasmania. We sequenced the scrubtit genome using PacBio HiFi and undertook a population genomic study of the King Island and Tasmanian scrubtits using a double-digest restriction site-associated DNA (ddRAD) dataset of 5,239 SNP loci. The genome was 1.48 Gb long, comprising 1,518 contigs with an N50 of 7.715 Mb. King Island scrubtits formed one of four overall genetic clusters, but separated into three distinct subpopulations when analysed independently of the Tasmanian scrubtit. Pairwise FST values were greater among the King Island scrubtit subpopulations than among most Tasmanian scrubtit subpopulations. Genetic diversity was lower and inbreeding coefficients were higher in the King Island scrubtit than all except one of the Tasmanian scrubtit subpopulations. We observed crown baldness in 8/15 King Island scrubtits, but 0/55 Tasmanian scrubtits. Six loci were significantly associated with baldness, including one within the DOCK11 gene which is linked to early feather development. Contemporary gene flow between King Island scrubtit subpopulations is unlikely, with further field monitoring required to quantify the fitness consequences of its small population size, low genetic diversity and high inbreeding. Evidence-based conservation actions can then be implemented before the taxon goes extinct.

2.
Heliyon ; 10(7): e28822, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38601671

RESUMEN

Background: Physiological modelling often involves models described by large numbers of variables and significant volumes of clinical data. Mathematical interpretation of such models frequently necessitates analysing data points in high-dimensional spaces. Existing algorithms for analysing high-dimensional points either lose important dimensionality or do not describe the full position of points. Hence, there is a need for an algorithm which preserves this information. Methods: The most-distant uncovered point (MDUP) hypersphere method is a binary classification approach which defines a collection of equidistant N-dimensional points as the union of hyperspheres. The method iteratively generates hyperspheres at the most distant point in the interest region not yet contained within any hypersphere, until the entire region of interest is defined by the union of all generated hyperspheres. This method is tested on a 7-dimensional space with up to 35.8 million points representing feasible and infeasible spaces of model parameters for a clinically validated cardiovascular system model. Results: For different numbers of input points, the MDUP hypersphere method tends to generate large spheres away from the boundary of feasible and infeasible points, but generates the greatest number of relatively much smaller spheres around the boundary of the region of interest to fill this space. Runtime scales quadratically, in part because the current MDUP implementation is not parallelised. Conclusions: The MDUP hypersphere method can define points in a space of any dimension using only a collection of centre points and associated radii, making the results easily interpretable. It can identify large continuous regions, and in many cases capture the general structure of a region in only a relative few hyperspheres. The MDUP method also shows promise for initialising optimisation algorithm starting conditions within pre-defined feasible regions of model parameter spaces, which could improve model identifiability and the quality of optimisation results.

3.
Curr Oncol ; 30(6): 5309-5321, 2023 05 26.
Artículo en Inglés | MEDLINE | ID: mdl-37366886

RESUMEN

BACKGROUND: With the global disease burden of cancer increasing, and with at least 60% of cancer patients requiring surgery and, hence, anaesthesia over their disease course, the question of whether anaesthetic and analgesia techniques during primary cancer resection surgery might influence long term oncological outcomes assumes high priority. METHODS: We searched the available literature linking anaesthetic-analgesic techniques and strategies during tumour resection surgery to oncological outcomes and synthesised this narrative review, predominantly using studies published since 2019. Current evidence is presented around opioids, regional anaesthesia, propofol total intravenous anaesthesia (TIVA) and volatile anaesthesia, dexamethasone, dexmedetomidine, non-steroidal anti-inflammatory medications and beta-blockers. CONCLUSIONS: The research base in onco-anaesthesia is expanding. There continue to be few sufficiently powered RCTs, which are necessary to confirm a causal link between any perioperative intervention and long-term oncologic outcome. In the absence of any convincing Level 1 recommending a change in practice, long-term oncologic benefit should not be part of the decision on choice of anaesthetic technique for tumour resection surgery.


Asunto(s)
Anestesia de Conducción , Anestésicos , Neoplasias , Propofol , Humanos , Anestésicos/uso terapéutico , Anestesia de Conducción/métodos , Anestesia General/métodos , Neoplasias/cirugía
4.
Ecology ; 104(7): e4098, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37258300

RESUMEN

Many studies have focused on vegetation across forest edges to study impacts of edges created by human activities on forest structure and composition, or patterns of vegetation at inherent natural edges. Our objective was to create a database of plant-related variables across different types of edges from various studies (mainly from across Canada, but also in Brazil and Belize) to facilitate edge research. We compiled data on vegetation along more than 300 transects perpendicular to forest edges adjacent to clear-cuts, burned areas, bogs, lakes, barrens, insect disturbances, and riparian areas from 24 studies conducted over the past three decades. Data were compiled for more than 400 plant species and forest structure variables (e.g., trees, logs, canopy cover). All data were collected with a similar sampling design of quadrats along transects perpendicular to forest edges, but with varying numbers of transects and quadrats, and distances from the edge. The purpose for most of the studies was either to determine the distance of edge influence (edge width) or to explore the pattern of vegetation along the edge to interior gradient. We provide data tables for the cover of plant species and functional groups, the species and size of live and dead trees, the density of saplings, maximum height of functional groups and shrub species, and the cover of functional groups at different heights (vertical distribution of vegetation). The Forest Edge Research Network (FERN) database provides extensive data on many variables that can be used for further study including meta-analyses and can assist in answering questions important to conservation efforts (e.g., how is distance of edge influence from created edges affected by different factors?). We plan to expand this database with subsequent studies from the authors and we invite others to contribute to make this a more global database. The data are released under a CC0 license. When using these data, we ask that you cite this data paper and any relevant publications listed in our metadata file. We also encourage you to contact the first author if you are planning to use or contribute to this database.


Asunto(s)
Bosques , Animales , Humanos , Insectos , Árboles , Humedales
5.
Proc Natl Acad Sci U S A ; 120(11): e2220272120, 2023 03 14.
Artículo en Inglés | MEDLINE | ID: mdl-36881624

RESUMEN

T cells are present in early stages of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and play a major role in disease outcome and long-lasting immunity. Nasal administration of a fully human anti-CD3 monoclonal antibody (Foralumab) reduced lung inflammation as well as serum IL-6 and C-reactive protein in moderate cases of COVID-19. Using serum proteomics and RNA-sequencing, we investigated the immune changes in patients treated with nasal Foralumab. In a randomized trial, mild to moderate COVID-19 outpatients received nasal Foralumab (100 µg/d) given for 10 consecutive days and were compared to patients that did not receive Foralumab. We found that naïve-like T cells were increased in Foralumab-treated subjects and NGK7+ effector T cells were reduced. CCL5, IL32, CST7, GZMH, GZMB, GZMA, PRF1, and CCL4 gene expression were downregulated in T cells and CASP1 was downregulated in T cells, monocytes, and B cells in subjects treated with Foralumab. In addition to the downregulation of effector features, an increase in TGFB1 gene expression in cell types with known effector function was observed in Foralumab-treated subjects. We also found increased expression of GTP-binding gene GIMAP7 in subjects treated with Foralumab. Rho/ROCK1, a downstream pathway of GTPases signaling was downregulated in Foralumab-treated individuals. TGFB1, GIMAP7, and NKG7 transcriptomic changes observed in Foralumab-treated COVID-19 subjects were also observed in healthy volunteers, MS subjects, and mice treated with nasal anti-CD3. Our findings demonstrate that nasal Foralumab modulates the inflammatory response in COVID-19 and provides a novel avenue to treat the disease.


Asunto(s)
Anticuerpos Monoclonales , COVID-19 , Animales , Humanos , Ratones , Administración Intranasal , Anticuerpos Monoclonales/uso terapéutico , Proteínas de Unión al GTP , Proteínas de la Membrana , Quinasas Asociadas a rho , SARS-CoV-2 , Linfocitos T , Factor de Crecimiento Transformador beta1/genética
6.
Comput Methods Programs Biomed ; 229: 107254, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36459818

RESUMEN

BACKGROUND: Central blood pressure (BP) better reflects the loading conditions on the major organs and is more closely correlated with future cardiovascular events. The increased invasiveness and risk of infection prevents the routine measurement of central BP. Arterial transfer functions can provide central BP estimates from clinically available peripheral measurements. However, current methods are either generalized, potentially lacking the ability to adapt to inter and intra subject variability, or individualized based on additional, clinically unavailable, pulse transit time measurements. This work proposes a novel, self-contained method for individualizing an arterial transfer function from a single peripheral pressure measurement, capable of accurately estimating central BP in a range of hemodynamic conditions. METHODS: Pulse wave analysis of femoral BP waves was employed to formulate initial approximations of central BP and arterial inlet flow waveforms, to serve as objective functions for the identification of all model parameters. Root mean squared error (RMSE), and systolic and pulse pressure errors were assessed with respect to invasive aortic BP measurements in a seven (7) porcine endotoxin experiments. Systolic and pulse pressure errors were analysed using Bland-Altman analysis. Method accuracy is also compared with an idealized transfer function, derived using the measured aortic-femoral pulse transit time and minimizing the RMSE of model output pressure with respect to reference aortic pressure, a generalized transfer function model, and invasive femoral pressure measurements. RESULTS: Mean bias and limits of agreement (95% CI) for the proposed method were 1.0(-4.6, 6.7)mmHg and -1.0(-6.6, 4.6)mmHg for systolic and pulse pressure, respectively, compared to 3.6(-0.9, 8.2)mmHg and 2.7(-1.8, 7.3)mmHg for the generalized transfer function model. Mean bias and limits of agreement for femoral pressure measurements were -6.4(-15.0, 2.3)mmHg and -9.4(-18.1, -0.8)mmHg, for systolic and pulse pressure, respectively. The pooled mean and standard deviation of the RMSE produced by the single measurement method, relative to reference aortic pressure, was 4.3(1.1)mmHg, consistent with estimates produced by the idealized transfer function, 3.9(1.2)mmHg, and improving of the generalized transfer function, 4.6(1.4)mmHg. CONCLUSIONS: The proposed single measurement method provides accurate central BP estimates from routinely available peripheral pressure measurements, and nothing else. The method allows for the individualization of transfer functions on a per patient basis to better capture changes in patient condition during the progression of disease and subsequent treatment, at no additional clinical cost.


Asunto(s)
Arterias , Determinación de la Presión Sanguínea , Animales , Porcinos , Presión Sanguínea/fisiología , Determinación de la Presión Sanguínea/métodos , Aorta/fisiología , Hemodinámica , Análisis de la Onda del Pulso/métodos
7.
Anim Microbiome ; 4(1): 67, 2022 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-36564793

RESUMEN

BACKGROUND: Microbes play a role in their host's fundamental ecological, chemical, and physiological processes. Host life-history traits from defence to growth are therefore determined not only by the abiotic environment and genotype but also by microbiota composition. However, the relative importance and interactive effects of these factors may vary between organisms. Such connections remain particularly elusive in Lepidoptera, which have been argued to lack a permanent microbiome and have microbiota primarily determined by their diet and environment. We tested the microbiome specificity and its influence on life-history traits of two colour genotypes of the wood tiger moth (Arctia plantaginis) that differ in several traits, including growth. All individuals were grown in the laboratory for several generations with standardized conditions. We analyzed the bacterial community of the genotypes before and after a reciprocal frass (i.e., larval faeces) transplantation and followed growth rate, pupal mass, and the production of defensive secretion. RESULTS: After transplantation, the fast-growing genotype grew significantly slower compared to the controls, but the slow-growing genotype did not change its growth rate. The frass transplant also increased the volume of defensive secretions in the fast-growing genotype but did not affect pupal mass. Overall, the fast-growing genotype appeared more susceptible to the transplantation than the slow-growing genotype. Microbiome differences between the genotypes strongly suggest genotype-based selective filtering of bacteria from the diet and environment. A novel cluster of insect-associated Erysipelotrichaceae was exclusive to the fast-growing genotype, and specific Enterococcaceae were characteristic to the slow-growing genotype. These Enterococcaceae became more prevalent in the fast-growing genotype after the transplant, which suggests that a slower growth rate is potentially related to their presence. CONCLUSIONS: We show that reciprocal frass transplantation can reverse some genotype-specific life-history traits in a lepidopteran host. The results indicate that genotype-specific selective filtering can fine-tune the bacterial community at specific life stages and tissues like the larval frass, even against a background of a highly variable community with stochastic assembly. Altogether, our findings suggest that the host's genotype can influence its susceptibility to being colonized by microbiota, impacting key life-history traits.

8.
Comput Biol Med ; 151(Pt A): 106235, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36334361

RESUMEN

Mechanical ventilation is well known for having detrimental effects on the cardiovascular system, particularly when using high positive end-expiratory pressure. High positive end-expiratory pressure levels cause a decrease in stroke volume, which, under normal conditions, usually bring about a decrease in stressed blood volume. Stressed blood volume, defined as the total pressure generating volume of the cardiovascular system, has been shown to be a potential index of fluid responsiveness, making it a potentially important diagnostic tool. Generally, respiratory and haemodynamic care are provided independently of one another. However, that positive end-expiratory pressure alters both stroke volume and stressed blood volume suggests both the pulmonary and cardiovascular state should be conjointly optimised and used to guide positive end-expiratory pressure. However, the complex and patient-specific nature of cardiopulmonary interactions which occur during mechanical ventilation presents a challenge for accurate modelling of respiratory and cardiovascular interactions required to better optimise care. Previous models attempting to incorporate cardiopulmonary interactions have suffered from poor reliability at higher PEEP levels, largely due to an exaggerated effect of intrathoracic pressure on the cardiovascular system. A new parameter, alpha, is added to a previously validated cardiopulmonary model, to modulate the percentage of intrathoracic pressure applied to the vena cava and left ventricle. The new parameter aims to increase reliability under high PEEP conditions as well as provide a patient specific solution to modelling cardiopulmonary interactions. The results from the identified optimal alpha are compared to the original model to investigate how this new parameter may be used to create a more patient-specific cardiopulmonary model, which would be better suited for guidance of care in the ICU.


Asunto(s)
Respiración con Presión Positiva , Respiración Artificial , Humanos , Reproducibilidad de los Resultados , Respiración con Presión Positiva/métodos , Corazón , Volumen Sistólico
9.
Proc Biol Sci ; 289(1978): 20220358, 2022 07 13.
Artículo en Inglés | MEDLINE | ID: mdl-35858071

RESUMEN

Mistletoes are hemiparasitic plants and keystone species in many ecosystems globally. Given predicted increases in drought frequency and intensity, mistletoes may be crucial for moderating drought impacts on community structure. Dependent on host vascular flows, mistletoes can succumb to stress when water availability falls, making them susceptible to mortality during drought. We counted mistletoe across greater than 350 000 km2 of southeastern Australia and conducted standardized bird surveys between 2016 and 2021, spanning a major drought event in 2018-2019. We aimed to identify predictors of mistletoe abundance and mortality and determine whether mistletoes might moderate drought impacts on woodland birds. Live mistletoe abundance varied with tree species composition, land use and presence of mistletoebirds. Mistletoe mortality was widespread, consistent with high 2018/2019 summer temperatures, low 2019/2020 summer rainfall and the interaction between summer temperatures and rainfall in 2019/2020. The positive association between surviving mistletoes and woodland birds was greatest in the peak drought breeding seasons of 2018/2019 and 2019/2020, particularly for small residents and insectivores. Paradoxically, mistletoes could moderate drought impacts on birds, but are themselves vulnerable to drought-induced mortality. An improved understanding of the drivers and dynamics of mistletoe mortality is needed to address potential cascading trophic impacts associated with mistletoe die-off.


Asunto(s)
Muérdago , Animales , Aves , Sequías , Ecosistema , Fitomejoramiento
10.
Sex Med ; 10(4): 100535, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35667245

RESUMEN

BACKGROUND: Intracavernosal injection therapy (ICI) is an effective intervention used to treat erectile dysfunction (ED). It has been proposed that caution should be exercised when prescribing ICI to patients currently taking anticoagulants (AC) due to the theoretical increased risk of bleeding, however, there is limited literature describing complication rates of actively anticoagulated patients utilizing ICI. AIM: We sought to determine whether there was a difference in bleeding and other complications in a cohort of patients using ICI therapy with or without concurrent AC use. METHODS: We reviewed our institutional electronic health record and identified 168 patients who were seen in our clinic from January to August 2020 who had either currently or previously utilized ICI therapy for ED treatment. These patients were surveyed regarding their ICI therapy as well as given the erectile dysfunction inventory for treatment satisfaction questionnaire. Data from 85 patients was obtained; 43 concurrently using AC during ICI therapy and 42 with no AC use. Fisher's exact test for categorical variables and a 2-tailed t-test were used with P < .05 considered to be significant. OUTCOME: Documented bleeding events (eg, bruising, hematoma), complications, and mean erectile dysfunction inventory for treatment satisfaction scores were compared between the 2 groups. RESULTS: There were more absolute bleeding complications in the AC group vs the no AC group, with 3 of 43 AC patients (7%, 95% confidence interval: 2.4-18.6) and 0/42 no AC patients (0%, 95% confidence interval: 0-8.4) experiencing some type of bleeding complication on ICI. However, there was no statistically significant difference found in overall or stratified documented bleeding events and complications between the 2 groups. CLINICAL IMPLICATIONS: Patients with concurrent AC usage on ICI therapy reported a higher rate of absolute bleeding complications than our non-AC group. STRENGTHS AND LIMITATIONS: The strength of this study is addressing question of safety of ICI therapy in patients with concurrent AC usage. Limitations include single-center retrospective study design and underpowered sample size limiting confidence with which conclusions from data should guide future patient counseling regarding ICI risks. CONCLUSION: Findings from a single-center cohort of patients suggest that ICI therapy may be a safe and effective treatment modality for ED in patients with concurrent anticoagulant usage, however, given the higher rate of absolute bleeding events in our AC cohort, future assessment in a higher-powered study is warranted in determining a more accurate estimation of risk or propensity for bleeding complications in patients on AC using ICI therapy. Blum KA, Mehr JP, Green T, et al. Complication Rates in Patients Using Intracavernosal Injection Therapy for Erectile Dysfunction With or Without Concurrent Anticoagulant Use-A Single-Center, Retrospective Pilot Study. Sex Med 2022;10:100535.

11.
Comput Methods Programs Biomed ; 220: 106819, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35461125

RESUMEN

BACKGROUND AND OBJECTIVE: Mechanical ventilation causes adverse effects on the cardiovascular system. However, the exact nature of the effects on haemodynamic parameters is not fully understood. A recently developed cardio-vascular system model which incorporates cardio-pulmonary interactions is compared to the original 3-chamber cardiovascular model to investigate the exact effects of mechanical ventilation on haemodynamic parameters and to assess the trade-off of model complexity and model reliability between the 2 models. METHODS: Both the cardio-pulmonary and three chamber models are used to identify cardiovascular system parameters from aortic pressure, left ventricular volume, airway flow and airway pressure measurements from 4 pigs during a preload reduction manoeuvre. Outputs and parameter estimations from both models are contrasted to assess the relative performance of each model and to further investigate the effects of mechanical ventilation on haemodynamic parameters. RESULTS: Both models tracked measurements accurately as expected. There was no identifiable increase in error from the added complexity of the cardio-pulmonary model, with both models having a mean average error below 0.5% for all pigs. Identified left ventricle and vena cava elastances of the 3-chamber model was found to diverge exponentially with PEEP from identified left ventricle and vena cava elastances of the cardio-pulmonary model. The r2 of the fit for each pig ranged from 0.888 to 0.998 for left ventricle elastance divergence and from 0.905 to 0.999 for vena cava elastance divergence. All other identified parameters showed no significant difference between models. CONCLUSIONS: Despite the increase in model complexity, there was no loss in the cardio-pulmonary model's ability to accurately estimate haemodynamic parameters and reproduce system dynamics. Furthermore, the cardio-pulmonary model was able to demonstrate how mechanical ventilation affected parameter estimations as PEEP was increased. The 3-chamber model was shown to produce parameter estimations which diverged exponentially with PEEP, while the cardiopulmonary model estimations remained more stable, suggesting its ability to produce more physiologically accurate parameter estimations under higher PEEP conditions.


Asunto(s)
Respiración con Presión Positiva , Respiración Artificial , Animales , Corazón , Ventrículos Cardíacos , Hemodinámica/fisiología , Reproducibilidad de los Resultados , Porcinos
12.
Proc Biol Sci ; 288(1961): 20211819, 2021 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-34666517

RESUMEN

Antibiotics have long been used in the raising of animals for agricultural, industrial or laboratory use. The use of subtherapeutic doses in diets of terrestrial and aquatic animals to promote growth is common and highly debated. Despite their vast application in animal husbandry, knowledge about the mechanisms behind growth promotion is minimal, particularly at the molecular level. Evidence from evolutionary research shows that immunocompetence is resource-limited, and hence expected to trade off with other resource-demanding processes, such as growth. Here, we ask if accelerated growth caused by antibiotics can be explained by genome-wide trade-offs between growth and costly immunocompetence. We explored this idea by injecting broad-spectrum antibiotics into wood tiger moth (Arctia plantaginis) larvae during development. We follow several life-history traits and analyse gene expression (RNA-seq) and bacterial (r16S) profiles. Moths treated with antibiotics show a substantial depletion of bacterial taxa, faster growth rate, a significant downregulation of genes involved in immunity and significant upregulation of growth-related genes. These results suggest that the presence of antibiotics may aid in up-keeping the immune system. Hence, by reducing the resource load of this costly process, bodily resources may be reallocated to other key processes such as growth.


Asunto(s)
Rasgos de la Historia de Vida , Mariposas Nocturnas , Animales , Antibacterianos/farmacología , Evolución Biológica , Larva , Mariposas Nocturnas/fisiología
13.
Comput Methods Programs Biomed ; 204: 106062, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33813060

RESUMEN

BACKGROUND AND OBJECTIVES: Accurate, reproducible, and reliable real-time clinical measurement of stroke volume (SV) is challenging. To accurately estimate arterial mechanics and SV by pulse contour analysis, accounting for wave reflection, such as by a tube-load model, is potentially important. This study tests for the first time whether a dynamically identified tube-load model, given a single peripheral arterial input signal and pulse transit time (PTT), provides accurate SV estimates during hemodynamic instability. METHODS: The model is tested for 5 pigs during hemodynamic interventions, using either an aortic flow probe or admittance catheter for a validation SV measure. Performance is assessed using Bland-Altman and polar plot analysis for a series of long-term state-change and short-term dynamic events. RESULTS: The overall median bias and limits of agreement (2.5th, 97.5th percentile) from Bland-Altman analysis were -10% [-49, 36], and -1% [-28,20] for state-change and dynamic events, respectively. The angular limit of agreement (maximum of 2.5th, 97.5th percentile) from polar-plot analysis for state-change and dynamic interventions was 35.6∘, and 35.2∘, respectively. CONCLUSION: SV estimation agreement and trending performance was reasonable given the severity of the interventions. This simple yet robust method has potential to track SV within acceptable limits during hemodynamic instability in critically ill patients, provided a sufficiently accurate PTT measure.


Asunto(s)
Hemodinámica , Análisis de la Onda del Pulso , Animales , Arterias , Gasto Cardíaco , Frecuencia Cardíaca , Humanos , Volumen Sistólico , Porcinos
14.
Biomed Phys Eng Express ; 6(1): 015031, 2020 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-33438619

RESUMEN

Leipzig-style skin brachytherapy applicators are an excellent choice for the treatment of small surface lesions, since they can be used with a high dose rate source to produce a tightly constrained treatment field on the desired area of the skin. The dosimetry of these applicators is challenging to independently verify due to their small dimensions, complex energy spectrum and steep dose gradients. In particular the close proximity of the brachytherapy source to the treatment region is cause for concern, since small variations in the position of the radioactive source may significantly affect the resulting dose distribution. The aim of this work was to assess the dosimetry of these applicators using three independently techniques and use these results to examine the effect of variation in source position on the dose distribution. Simulation of different sized applicators in conjunction with a Gammamed + Ir192 source was performed using the EGSnrc Monte Carlo code. Dose distributions at the prescription depth and at the surface generated by Monte Carlo were compared to the outputs of a commercially available treatment planning system and measurements using radiochromic film. Source displacements of up to 0.5 mm in the vertical direction, 0.65 mm in the horizontal direction, and rotations of the source by up to 5° were all simulated. Changes in dose of over 6% at the prescription point and reductions in coverage at the 100% isodose level of several millimetres were observed even for small shifts of the source from its intended position. This work demonstrates that variation in the position of the radiation source is the dominant source of uncertainty in the use of these types of applicators. Centres wishing to perform treatments using these applicators are advised to take steps to control the uncertainty and ensure it remains at an acceptable level.


Asunto(s)
Braquiterapia/métodos , Simulación por Computador , Radioisótopos de Iridio/uso terapéutico , Método de Montecarlo , Fantasmas de Imagen , Radiometría/métodos , Enfermedades de la Piel/radioterapia , Humanos , Dosificación Radioterapéutica
15.
Ann Biomed Eng ; 48(2): 682-694, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31768794

RESUMEN

Total stressed blood volume ([Formula: see text]) and arterial elastance ([Formula: see text]) are two potentially important, clinically applicable metrics for guiding treatment in patients with altered hemodynamic states. Defined as the total pressure generating blood in the circulation, [Formula: see text] is a potential direct measurement of tissue perfusion, a critical component in treatment of sepsis. [Formula: see text] is closely related to arterial tone thus provides insight into cardiac efficiency. However, it is not clinically feasible or ethical to measure [Formula: see text] in patients, so a three chambered cardiovascular system model using measured left ventricle pressure and volume, aortic pressure and central venous pressure is implemented to identify [Formula: see text] and [Formula: see text] from clinical data. [Formula: see text] and [Formula: see text] are identified from clinical data from six (6) pigs, who have undergone clinical procedures aimed at simulating septic shock and subsequent treatment, to identify clinically relevant changes. A novel, validated trend analysis method is used to adjudge clinically significant changes in state in the real-time [Formula: see text] and [Formula: see text] traces. Results matched hypothesised increases in [Formula: see text] during fluid therapy, with a mean change of + 21% during initial therapy, and hypothesised decreases during endotoxin induced sepsis, with a mean change of - 29%. [Formula: see text] displayed the hypothesised reciprocal behaviour with a mean changes of - 12 and + 30% during initial therapy and endotoxin induced sepsis, respectively. The overall results validate the efficacy of [Formula: see text] in tracking changes in hemodynamic state in septic shock and fluid therapy.


Asunto(s)
Presión Sanguínea , Modelos Cardiovasculares , Modelación Específica para el Paciente , Sepsis/fisiopatología , Animales , Modelos Animales de Enfermedad , Prueba de Estudio Conceptual , Porcinos
16.
Philos Trans R Soc Lond B Biol Sci ; 374(1783): 20190069, 2019 10 14.
Artículo en Inglés | MEDLINE | ID: mdl-31438812

RESUMEN

Antipredator strategies of the pupal stage in insects have received little attention in comparison to larval or adult stages. This is despite the fact that predation risk can be high during the pupal stage, making it a critical stage for subsequent fitness. The immobile pupae are not, however, defenceless; a wide range of antipredator strategies have evolved against invertebrate and vertebrate predators. The most common strategy seems to be 'avoiding encounters with predators' by actively hiding in vegetation and soil or via cryptic coloration and masquerade. Pupae have also evolved behavioural and secondary defences such as defensive toxins, physical defences or deimatic movements and sounds. Interestingly, warning coloration used to advertise unprofitability has evolved very rarely, even though the pupal stage often contains defensive toxins in chemically defended species. In some species, pupae gain protection from conspecifics or mimic chemical and auditory signals and thereby manipulate other species to protect them. Our literature survey highlights the importance of studying selection pressures across an individual's life stages to predict how ontogenetic variation in selective environments shapes individual fitness and population dynamics in insects. Finally, we also suggest interesting avenues for future research to pursue. This article is part of the theme issue 'The evolution of complete metamorphosis'.


Asunto(s)
Cadena Alimentaria , Insectos/fisiología , Pupa/fisiología , Animales , Ambiente , Insectos/genética , Insectos/crecimiento & desarrollo , Pupa/genética , Pupa/crecimiento & desarrollo , Selección Genética
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2019: 2951-2954, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31946509

RESUMEN

Sepsis can cause major complications in the cardiovascular system. Accurate monitoring of model-based bio-markers, such as total stressed blood volume, SBVT , have been shown to be important parameters in determining the effectiveness of fluid therapy in sepsis patients. Another such parameter is arterial elastance, Ea, which is a measure of the relative stiffness of arteries. This work investigates the effect of fluid therapy and induced sepsis on these parameters through a state average analysis and comparison to previously defined clinical references. A three chambered lumped cardiovascular system model was implemented to develop model based analogues of the two parameters in six porcine subjects. A mean state average increase of 20.9% in SBVT was found in response to fluid therapy, while a mean state average decrease of 32.7% occurred, in surviving subjects, after sepsis was induced. Ea showed a mean state average drop of 12.2% during fluid therapy and an increase of 45% after sepsis is induced. Both results match hypothesised expectations.


Asunto(s)
Arterias/fisiología , Volumen Sanguíneo , Modelos Cardiovasculares , Sepsis/fisiopatología , Resistencia Vascular , Animales , Presión Sanguínea , Elasticidad , Fluidoterapia , Porcinos
18.
J Biol Chem ; 286(20): 17898-909, 2011 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-21383009

RESUMEN

Insulin-like growth factor-binding protein-3 (IGFBP-3) is a multifunctional protein known for modulating mitogenic and metabolic actions of IGFs as well as exerting a variety of biological actions not involving IGFs. Here, we show that IGFBP-3 blocks specific physiological consequences of asthma in an IGF-independent manner in vitro and in vivo. IGFBP-3 treatment effectively reduced all physiological manifestations of asthma examined in vivo (airway hyper-responsiveness, cellular and pathological changes in bronchoalveolar lavage fluid and lung tissue, and expression of numerous proinflammatory molecules). These unique IGFBP-3 effects were further confirmed in IGFBP-3-transgenic mice, thus strengthening the notion of IGFBP-3 actions within the respiratory system. Using human epithelial cells, we demonstrated the following: 1) IGFBP-3 blocks TNF-α-induced expression of proinflammatory molecules; 2) IGFBP-3 attenuates the TNF-α-induced migratory response of eosinophils; and 3) IGFBP-3 negatively regulates TNF-α-induced expression of the key NF-κB regulatory molecules IκBα and p65-NF-κB at the post-translational level. We identified that IGFBP-3 degrades IκBα and p65-NF-κB proteins through IGFBP-3 receptor (IGFBP-3R)-mediated activation of caspases thereby inhibiting TNF-α-induced activation of NF-κB signaling cascades. This unique IGFBP-3/IGFBP-3R action was further confirmed by demonstrating complete inhibition of IGFBP-3 action in the presence of caspase inhibitors as well as IGFBP-3R siRNAs. Non-IGF-binding IGFBP-3 mutants further proved the IGF-independent action of IGFBP-3. Our findings indicate that IGFBP-3 inhibits airway inflammation and hyper-responsiveness via an IGF-independent mechanism that involves activation of IGFBP-3R signaling and cross-talk with NF-κB signaling. The IGFBP-3/IGFBP-3R system therefore plays a pivotal role in the pathogenesis of asthma and can serve as a newly identified potential therapeutic target for this debilitating disease.


Asunto(s)
Asma/metabolismo , Caspasas/metabolismo , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Receptores de Superficie Celular/metabolismo , Transducción de Señal , Factor de Transcripción ReIA/metabolismo , Animales , Asma/genética , Caspasas/genética , Línea Celular , Movimiento Celular , Activación Enzimática/genética , Eosinófilos/metabolismo , Femenino , Humanos , Proteínas I-kappa B/genética , Proteínas I-kappa B/metabolismo , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/genética , Masculino , Ratones , Ratones Transgénicos , Mutación , Inhibidor NF-kappaB alfa , Receptores de Superficie Celular/genética , Factor de Transcripción ReIA/genética , Factor de Necrosis Tumoral alfa/biosíntesis , Factor de Necrosis Tumoral alfa/genética
19.
J Biol Chem ; 282(25): 18108-18115, 2007 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-17478427

RESUMEN

Transglutaminase 2 (TG2, tissue transglutaminase) is a multifunctional protein involved in cross-linking a variety of proteins, including retinoblastoma protein (Rb). Here we show that Rb is also a substrate for the recently identified serine/threonine kinase activity of TG2 and that TG2 phosphorylates Rb at the critically important Ser780 residue. Furthermore, phosphorylation of Rb by TG2 destabilizes the Rb.E2F1 complex. TG2 phosphorylation of Rb was abrogated by high Ca2+ concentrations, whereas TG2 transamidating activity was inhibited by ATP. TG2 was itself phosphorylated by protein kinase A (PKA). Phosphorylation of TG2 by PKA attenuated its transamidating activity and enhanced its kinase activity. Activation of PKA in mouse embryonic fibroblasts (MEF) with dibutyryl-cAMP enhanced phosphorylation of both TG2 and Rb by a process that was inhibited by the PKA inhibitor H89. Treatment with dibutyryl-cAMP enhanced Rb phosphorylation in MEFtg2+/+ cells but not in MEFtg2-/- cells. These data indicate that Rb is a substrate for TG2 kinase activity and suggest that phosphorylation of Rb, which results from activation of PKA in fibroblasts, is indirect and requires TG2 kinase activity.


Asunto(s)
Calcio/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Proteínas de Unión al GTP/metabolismo , Proteína de Retinoblastoma/metabolismo , Transglutaminasas/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Apoptosis , Ciclo Celular , Línea Celular , Fibroblastos/metabolismo , Humanos , Ratones , Fosforilación , Proteína Glutamina Gamma Glutamiltransferasa 2 , Fase S , Serina/química
20.
Diabetes Care ; 30(2): 286-91, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17259496

RESUMEN

OBJECTIVE: We sought to compare the relationship between body composition, insulin resistance, and inflammatory adipokines in Aboriginal Canadian women, who are at high risk of vascular disease, with white women. RESEARCH DESIGN AND METHODS: A subgroup of the First Nations Bone Health Study population, consisting of 131 Aboriginal women and 132 matched white women, was utilized. Body composition was determined by whole-body dual X-ray absorptiometry, and blood analytes were measured after an overnight fast. RESULTS: After excluding individuals with diabetes, A1C, BMI, percent trunk fat, and homeostasis model assessment of insulin resistance (HOMA-IR) were greater in First Nation women compared with white women, whereas adiponectin, retinol binding protein (RBP)4, and insulin-like growth factor binding protein-1 (IGFBP-1) were lower. First Nation women had more trunk fat for any given level of total fat than white women. There were no differences in resistin, leptin, tumor necrosis factor (TNF)-alpha, or C-reactive protein (CRP) levels between First Nation and white women. Insulin resistance correlated with leptin and inversely with adiponectin levels in both First Nation and white women. There were weak correlations between insulin resistance and TNF-alpha, interleukin-6, and CRP, but these were not significant after correction for body fat. No correlation was found between RBP4 and insulin resistance. ANCOVA revealed a higher HOMA-IR adjusted for total body fat in First Nation women than in white women (P = 0.015) but not HOMA-IR adjusted for trunk fat (P > 0.2). CONCLUSIONS: First Nation women are more insulin resistant than white women, and this is explained by trunk fat but not total fat. Despite the increased insulin resistance, inflammatory adipokines are not significantly increased in First Nation women compared with white women.


Asunto(s)
Adiponectina/sangre , Etnicidad , Inflamación/fisiopatología , Resistencia a la Insulina , Enfermedades Vasculares/epidemiología , Adulto , Glucemia/metabolismo , Composición Corporal , Índice de Masa Corporal , Femenino , Humanos , Indígenas Norteamericanos , Inflamación/sangre , Insulina/sangre , Manitoba , Persona de Mediana Edad , Factores de Riesgo , Población Blanca
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