RESUMO
Dealing with an uncertain or missed diagnosis is commonplace in the intensive care unit setting. Affected patients are subject to a potential decrease in quality of care and a greater risk of a poor outcome. The diagnostic process is a complex task that starts with information gathering, followed by integration and interpretation of data, hypothesis generation and, finally, confirmation of a (hopefully correct) diagnosis. This may be particularly challenging in the patient who is critically ill where a good history may not be forthcoming and/or clinical, laboratory and imaging features are non-specific. The aim of this narrative review is to analyse and describe common causes of diagnostic error in the intensive care unit, highlighting the multiple types of cognitive bias, and to suggest a diagnostic framework. To inform this review, we performed a literature search to identify relevant articles, particularly those pertinent to unclear diagnoses in patients who are critically ill. Clinicians should be cognisant as to how they formulate diagnoses and utilise debiasing strategies. Multidisciplinary teamwork and more time spent with the patient, supported by effective and efficient use of electronic healthcare records and decision support resources, is likely to improve the quality of the diagnostic process, patient care and outcomes.
Assuntos
Estado Terminal , Unidades de Terapia Intensiva , Humanos , IncertezaRESUMO
BACKGROUND: 16S rRNA gene sequencing is currently the most common way of determining the composition of microbiota. This technique has enabled many new discoveries to be made regarding the relevance of microbiota to the health and disease of the host. However, compared to other diagnostic techniques, 16S rRNA gene sequencing is fairly costly and labor intensive, leaving room for other techniques to improve on these aspects. RESULTS: The current study aimed to compare the output of 16S rRNA gene sequencing to the output of the quick IS-pro analysis, using vaginal swab samples from 297 women of reproductive age. 16S rRNA gene sequencing and IS-pro analyses yielded very similar vaginal microbiome profiles, with a median Pearson's R2 of 0.97, indicating a high level of similarity between both techniques. CONCLUSIONS: We conclude that the results of 16S rRNA gene sequencing and IS-pro are highly comparable and that both can be used to accurately determine the vaginal microbiota composition, with the IS-pro analysis having the benefit of rapidity.
Assuntos
Bactérias/genética , Técnicas Bacteriológicas/normas , Microbiota/genética , Vagina/microbiologia , Adulto , Técnicas Bacteriológicas/economia , Eletroforese Capilar/economia , Eletroforese Capilar/normas , Feminino , Humanos , RNA Ribossômico 16S/genética , Análise de Sequência de DNA/economia , Análise de Sequência de DNA/normasRESUMO
The E2 protein in classical swine fever (CSF) virus (CSFV) is the major virus structural glycoprotein and is an essential component of the viral particle. E2 has been shown to be involved in several functions, including virus adsorption, induction of protective immunity, and virulence in swine. Using the yeast two-hybrid system, we previously identified a swine host protein, dynactin subunit 6 (DCTN6) (a component of the cell dynactin complex), as a specific binding partner for E2. We confirmed the interaction between DCTN6 and E2 proteins in CSFV-infected swine cells by using two additional independent methodologies, i.e., coimmunoprecipitation and proximity ligation assays. E2 residues critical for mediating the protein-protein interaction with DCTN6 were mapped by a reverse yeast two-hybrid approach using a randomly mutated E2 library. A recombinant CSFV mutant, E2ΔDCTN6v, harboring specific substitutions in those critical residues was developed to assess the importance of the E2-DCTN6 protein-protein interaction for virus replication and virulence in swine. CSFV E2ΔDCTN6v showed reduced replication, compared with the parental virus, in an established swine cell line (SK6) and in primary swine macrophage cultures. Remarkably, animals infected with CSFV E2ΔDCTN6v remained clinically normal during the 21-day observation period, which suggests that the ability of CSFV E2 to bind host DCTN6 protein efficiently during infection may play a role in viral virulence.IMPORTANCE Structural glycoprotein E2 is an important component of CSFV due to its involvement in many virus activities, particularly virus-host interactions. Here, we present the description and characterization of the protein-protein interaction between E2 and the swine host protein DCTN6 during virus infection. The E2 amino acid residues mediating the interaction with DCTN6 were also identified. A recombinant CSFV harboring mutations disrupting the E2-DCTN6 interaction was created. The effect of disrupting the E2-DCTN6 protein-protein interaction was studied using reverse genetics. It was shown that the same amino acid substitutions that abrogated the E2-DCTN6 interaction in vitro constituted a critical factor in viral virulence in the natural host, domestic swine. This highlights the potential importance of the E2-DCTN6 protein-protein interaction in CSFV virulence and provides possible mechanisms of virus attenuation for the development of improved CSF vaccines.
Assuntos
Vírus da Febre Suína Clássica/genética , Peste Suína Clássica/virologia , Complexo Dinactina/genética , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Proteínas do Envelope Viral/genética , Animais , Sítios de Ligação , Linhagem Celular , Peste Suína Clássica/mortalidade , Peste Suína Clássica/patologia , Vírus da Febre Suína Clássica/metabolismo , Vírus da Febre Suína Clássica/patogenicidade , Complexo Dinactina/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/virologia , Biblioteca Gênica , Macrófagos/metabolismo , Macrófagos/virologia , Mutação , Cultura Primária de Células , Ligação Proteica , Transdução de Sinais , Análise de Sobrevida , Suínos , Técnicas do Sistema de Duplo-Híbrido , Proteínas do Envelope Viral/metabolismo , Replicação ViralRESUMO
The Dietary Approaches to Stop Hypertension (DASH) eating pattern has been shown to reduce blood pressure (BP) in previous clinical trials. In the PREMIER study, an established behavioural intervention, with or without DASH, promoted greater weight loss than an advice-only control group, but effects of the DASH intervention on BP were weaker. In these analyses, PREMIER data were used to evaluate whether change in dairy product or fruit and vegetable (FV) intake during the first six intervention months impacted changes in weight and/or BP. Study participants were classified as having low or high intakes of dairy products (<1·5 v. ≥1·5 servings/d) and FV (<5 v. ≥5 servings/d) at baseline and 6 months. For dairy products, in particular, participants with higher baseline intakes tended to decrease their intakes during the intervention. In these analyses, subjects consuming <1·5 dairy servings/d at baseline whose intake increased during the intervention lost more weight than those whose intake decreased or remained low throughout (10·6 v. 7·0 pounds (4·8 v. 3·2 kg) lost, respectively, P = 0·002). The same was true for FV intake (11·0 v. 5·9 pounds (5·0 v. 2·7 kg) lost, P < 0·001). We also found synergistic effects of dairy products and FV on weight loss and BP reduction. Specifically, subjects who increased their intakes of dairy products and also consumed ≥5 servings of FV/d lost more weight and had greater reductions in BP than other groups; in addition, higher FV intakes had the greatest benefit to BP among those consuming more dairy products. These results provide evidence that the DASH pattern was most beneficial to individuals whose baseline diet was less consistent with DASH.
Assuntos
Dieta , Abordagens Dietéticas para Conter a Hipertensão , Comportamentos Relacionados com a Saúde , Hipertensão/dietoterapia , Estilo de Vida , Adulto , Pressão Sanguínea , Feminino , Humanos , Hipertensão/prevenção & controle , Masculino , Pessoa de Meia-IdadeRESUMO
In view of the current coronavirus disease 2019 (COVID-19) pandemic, patient care, including that of psychiatric patients, is facing unprecedented challenges. Treatment strategies for mental illness include psychotherapy and psychopharmacological interventions. The latter are associated with a multitude of adverse drug reactions (ADR); however, they may currently represent the preferred treatment due to restrictions regarding patient care (i.e. social distancing). Direct contact to patients may have to be reduced in favor of telephone calls or video conferences, so that new techniques in diagnosing and treating patients have to be established to guarantee patient safety. Patients should be extensively informed about relevant ADRs and physicians should actively ask patients about the timely recognition of ADRs. The use of psychotropic drugs may lead to an increased risk of developing ADRs, which are considered to be particularly unfavorable if they occur simultaneously with an acute infection or may even lead to an increased risk of infection. These include respiratory depression, agranulocytosis, intoxication by inhibition of metabolizing enzymes and venous thromboembolism, each of which may be associated with potentially fatal consequences; however, physicians should simultaneously ensure adequate efficacy of treatment, since the ongoing crisis may lead to a worsening of preexisting mental illnesses and to a surge in first onset of psychiatric disorders.
Assuntos
Infecções por Coronavirus , Pandemias , Pneumonia Viral , Psicoterapia , Psicotrópicos , Betacoronavirus , COVID-19 , Infecções por Coronavirus/psicologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Humanos , Pandemias/estatística & dados numéricos , Pneumonia Viral/psicologia , Psicoterapia/métodos , Psicoterapia/organização & administração , Psicotrópicos/administração & dosagem , Psicotrópicos/efeitos adversos , SARS-CoV-2RESUMO
STUDY QUESTION: Is the presence or absence of certain vaginal bacteria associated with failure or success to become pregnant after an in vitro fertilization (IVF) or IVF with intracytoplasmic sperm injection (IVF-ICSI) treatment? SUMMARY ANSWER: Microbiome profiling with the use of interspace profiling (IS-pro) technique enables stratification of the chance of becoming pregnant prior to the start of an IVF or IVF-ICSI treatment. WHAT IS KNOWN ALREADY: Live-birth rates for an IVF or IVF-ICSI treatment vary between 25 and 35% per cycle and it is difficult to predict who will or will not get pregnant after embryo transfer (ET). Recently, it was suggested that the composition of the vaginal microbiota prior to treatment might predict pregnancy outcome. Analysis of the vaginal microbiome prior to treatment might, therefore, offer an opportunity to improve the success rate of IVF or IVF-ICSI. STUDY DESIGN, SIZE, DURATION: In a prospective cohort study, 303 women (age, 20-42 years) undergoing IVF or IVF-ICSI treatment in the Netherlands were included between June 2015 and March 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: Study subjects provided a vaginal sample before the start of the IVF or IVF-ICSI procedure. The vaginal microbiota composition was determined using the IS-pro technique. IS-pro is a eubacterial technique based on the detection and categorization of the length of the 16S-23S rRNA gene interspace region. Microbiome profiles were assigned to community state types based on the dominant bacterial species. The predictive accuracy of the microbiome profiles for IVF and IVF-ICSI outcome of fresh ET was evaluated by a combined prediction model based on a small number of bacterial species. From this cohort, a model was built to predict outcome of fertility treatment. This model was externally validated in a cohort of 50 women who were undergoing IVF or IVF-ICSI treatment between March 2018 and May 2018 in the Dutch division of the MVZ VivaNeo Kinderwunschzentrum Düsseldorf, Germany. MAIN RESULTS AND THE ROLE OF CHANCE: In total, the vaginal microbiota of 192 women who underwent a fresh ET could be analysed. Women with a low percentage of Lactobacillus in their vaginal sample were less likely to have a successful embryo implantation. The prediction model identified a subgroup of women (17.7%, n = 34) who had a low chance to become pregnant following fresh ET. This failure was correctly predicted in 32 out of 34 women based on the vaginal microbiota composition, resulting in a predictive accuracy of 94% (sensitivity, 26%; specificity, 97%). Additionally, the degree of dominance of Lactobacillus crispatus was an important factor in predicting pregnancy. Women who had a favourable profile as well as <60% L. crispatus had a high chance of pregnancy: more than half of these women (50 out of 95) became pregnant. In the external validation cohort, none of the women who had a negative prediction (low chance of pregnancy) became pregnant. LIMITATIONS, REASONS FOR CAUTION: Because our study uses a well-defined study population, the results will be limited to the IVF or IVF-ICSI population. Whether these results can be extrapolated to the general population trying to achieve pregnancy without ART cannot be determined from these data. WIDER IMPLICATIONS OF THE FINDINGS: Our results indicate that vaginal microbiome profiling using the IS-pro technique enables stratification of the chance of becoming pregnant prior to the start of an IVF or IVF-ICSI treatment. Knowledge of their vaginal microbiota may enable couples to make a more balanced decision regarding timing and continuation of their IVF or IVF-ICSI treatment cycles. STUDY FUNDING/COMPETING INTEREST(S): This study was financed by NGI Pre-Seed 2014-2016, RedMedTech Discovery Fund 2014-2017, STW Valorisation grant 1 2014-2015, STW Take-off early phase trajectory 2015-2016 and Eurostars VALBIOME grant (reference number: 8884). The employer of W.J.S.S.C. has in collaboration with ARTPred acquired a MIND subsidy to cover part of the costs of this collaboration project. The following grants are received but not used to finance this study: grants from Innovatie Prestatie Contract, MIT Haalbaarheid, other from Dutch R&D tax credit WBSO, RedMedTech Discovery Fund, (J.D.d.J.). Grants from Ferring (J.S.E.L., K.F., C.B.L. and J.M.J.S.S.), Merck Serono (K.F. and C.B.L.), Dutch Heart Foundation (J.S.E.L.), Metagenics Inc. (J.S.E.L.), GoodLife (K.F.), Guerbet (C.B.L.). R.K. is employed by ARTPred B.V. during her PhD at Erasmus Medical Centre (MC). S.A.M. has a 100% University appointment. I.S.P.H.M.S., S.A.M. and A.E.B. are co-owners of IS-Diagnostics Ltd. J.D.d.J. is co-owner of ARTPred B.V., from which he reports personal fees. P.H.M.S. reports non-financial support from ARTPred B.V. P.H.M.S., J.D.d.J. and A.E.B. have obtained patents `Microbial population analysis' (9506109) and `Microbial population analysis' (20170159108), both licenced to ARTPred B.V. J.D.d.J. and A.E.B. report patent applications `Method and kit for predicting the outcome of an assisted reproductive technology procedure' (392EPP0) and patent `Method and kit for altering the outcome of an assisted reproductive technology procedure' by ARTPred. W.J.S.S.C. received personal consultancy and educational fees from Goodlife Fertility B.V. J.S.E.L. reports personal consultancy fees from ARTPred B.V., Titus Health B.V., Danone, Euroscreen and Roche during the conduct of the study. J.S.E.L. and N.G.M.B. are co-applicants on an Erasmus MC patent (New method and kit for prediction success of in vitro fertilization) licenced to ARTPred B.V. F.J.M.B. reports personal fees from Advisory Board Ferring, Advisory Board Merck Serono, Advisory Board Gedeon Richter and personal fees from Educational activities for Ferring, outside the submitted work. K.F. reports personal fees from Ferring (commercial sponsor) and personal fees from GoodLife (commercial sponsor). C.B.L. received speakers' fee from Ferring. J.M.J.S.S. reports personal fees and other from Merck Serono and personal fees from Ferring, unrelated to the submitted paper. The other authors declare that they have no competing interests. TRIAL REGISTRATION NUMBER: ISRCTN83157250. Registered 17 August 2018. Retrospectively registered.
Assuntos
Transferência Embrionária/estatística & dados numéricos , Infertilidade Feminina/terapia , Lactobacillus crispatus/isolamento & purificação , Microbiota , Injeções de Esperma Intracitoplásmicas/estatística & dados numéricos , Vagina/microbiologia , Adulto , Coeficiente de Natalidade , Tomada de Decisão Clínica/métodos , DNA Bacteriano/isolamento & purificação , Feminino , Alemanha , Humanos , Lactobacillus crispatus/genética , Modelos Estatísticos , Países Baixos , Valor Preditivo dos Testes , Gravidez , Estudos Prospectivos , RNA Ribossômico 16S/genética , Medição de Risco/métodos , Fatores de Tempo , Resultado do TratamentoRESUMO
The high-efficiency injection of a low-energy positron beam into the confinement volume of a magnetic dipole has been demonstrated experimentally. This was accomplished by tailoring the three-dimensional guiding-center drift orbits of positrons via optimization of electrostatic potentials applied to electrodes at the edge of the trap, thereby producing localized and essentially lossless cross-field particle transport by means of the E×B drift. The experimental findings are reproduced and elucidated by numerical simulations, enabling a comprehensive understanding of the process. These results answer key questions and establish methods for use in upcoming experiments to create an electron-positron plasma in a levitated dipole device.
RESUMO
An ensemble of low-energy positrons injected into a supported magnetic dipole trap can remain trapped for more than a second. Trapping experiments with and without a positive magnet bias yield confinement times up to τ_{A}=(1.5±0.1) and τ_{B}=(0.28±0.04) s, respectively. Supported by single-particle simulations, we conclude that the dominant mechanism limiting the confinement in this trap is scattering off of neutrals, which can lead to both radial transport and parallel losses onto the magnet surface. These results provide encouragement for plans to confine an electron-positron plasma in a levitated dipole trap.
RESUMO
BACKGROUND: Commercially available crystalloid solutions used for volume replacement do not exactly match the balance of electrolytes found in plasma. Large volume administration may lead to electrolyte imbalance and potential harm. We hypothesised that haemodilution using solutions containing different anions would result in diverse biochemical effects, particularly on acid-base status, and different outcomes. METHODS: Anaesthetised, fluid-resuscitated, male Wistar rats underwent isovolaemic haemodilution by removal of 10% blood volume every 15 min, followed by replacement with one of three crystalloid solutions based on acetate, lactate, or chloride. Fluids were administered in a protocolised manner to achieve euvolaemia based on echocardiography-derived left ventrical volumetric measures. Removed blood was sampled for plasma ions, acid-base status, haemoglobin, and glucose. This cycle was repeated at 15-min intervals until death. The primary endpoint was change in plasma bicarbonate within each fluid group. Secondary endpoints included time to death and cardiac function. RESULTS: During haemodilution, chloride-treated rats showed significantly greater decreases in plasma bicarbonate and strong ion difference levels compared with acetate- and lactate-treated rats. Time to death, total volume of fluid administered: chloride group 56 (3) ml, lactate group 62 (3) ml, and acetate group 65 (3) ml; haemodynamic and tissue oxygenation changes were, however, similar between groups. CONCLUSIONS: With progressive haemodilution, resuscitation with a chloride-based solution induced more acidosis compared with lactate- and acetate-based solutions, but outcomes were similar. No short-term impact was seen from hyperchloraemia in this model.
Assuntos
Equilíbrio Ácido-Base/efeitos dos fármacos , Soluções Cristaloides/farmacologia , Hidratação/métodos , Hemodiluição/métodos , Substitutos do Plasma/farmacologia , Acetatos/farmacologia , Acidose/sangue , Acidose/etiologia , Animais , Bicarbonatos/sangue , Cloretos/farmacologia , Soluções Cristaloides/efeitos adversos , Hidratação/efeitos adversos , Hemodinâmica/efeitos dos fármacos , Lactatos/farmacologia , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Substitutos do Plasma/efeitos adversos , Ratos WistarRESUMO
BACKGROUND: During early treatment of haemorrhagic shock, cerebral perfusion pressure can be restored by small-volume resuscitation with vasopressors. Whether this therapy is improved with additional fluid remains unknown. We assessed the value of terlipressin and lactated Ringer's solution (LR) on early recovery of microcirculation, tissue oxygenation, and mitochondrial and electrophysiological function in the rat cerebral cortex. METHODS: Animals treated with LR replacing three times (3LR) the volume bled (n=26), terlipressin (n=27), terlipressin plus 1LR (n=26), 2LR (n=16), or 3LR (n=15) were compared with untreated (n=36) and sham-operated rats (n=17). In vivo confocal microscopy was used to assess cortical capillary perfusion, changes in tissue oxygen concentration, and mitochondrial membrane potential and redox state. Electrophysiological function was assessed by cortical somatosensory evoked potentials, spinal cord dorsum potential, and peripheral electromyography. RESULTS: Compared with sham treatment, haemorrhagic shock reduced the mean (SD) area of perfused vessels [82% (sd 10%) vs 38% (12%); P<0.001] and impaired oxygen concentration, mitochondrial redox state [99% (4%) vs 59% (15%) of baseline; P<0.001], and somatosensory evoked potentials [97% (13%) vs 27% (19%) of baseline]. Administration of terlipressin plus 1LR or 2LR was able to recover these measures, but terlipressin plus 3LR or 3LR alone were not as effective. Spinal cord dorsum potential was preserved in all groups, but no therapy protected electromyographic function. CONCLUSIONS: Resuscitation from haemorrhagic shock using terlipressin with small-volume LR was superior to high-volume LR, with regard to cerebral microcirculation, and mitochondrial and electrophysiological functions.
Assuntos
Circulação Cerebrovascular/efeitos dos fármacos , Hidratação/métodos , Choque Hemorrágico/terapia , Terlipressina/uso terapêutico , Vasoconstritores/uso terapêutico , Animais , Córtex Cerebral/irrigação sanguínea , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos/métodos , Estimativa de Kaplan-Meier , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Potencial da Membrana Mitocondrial/fisiologia , Microcirculação/efeitos dos fármacos , Microscopia Confocal , Mitocôndrias/metabolismo , Oxirredução , Consumo de Oxigênio/efeitos dos fármacos , Distribuição Aleatória , Ratos Sprague-Dawley , Lactato de Ringer/farmacologia , Lactato de Ringer/uso terapêutico , Choque Hemorrágico/fisiopatologia , Terlipressina/farmacologia , Vasoconstritores/farmacologiaRESUMO
The endogenous cannabinoid 2-arachidonoyl glycerol (2-AG) is an anti-fibrotic lipid mediator that induces apoptosis in hepatic stellate cells (HSCs), but not in hepatocytes. However, the exact molecular mechanisms of this selective induction of HSC death are still unresolved. Interestingly, the inducible isoform of cyclooxygenase, COX-2, can metabolize 2-AG to pro-apoptotic prostaglandin glycerol esters (PG-GEs). We analyzed the roles of COX-2 and endocannabinoid-derived PG-GEs in the differential susceptibility of primary activated HSCs and hepatocytes toward 2-AG-induced cell death. HSCs displayed significant COX-2 expression in contrast to hepatocytes. Similar to 2-AG, treatment of HSCs with PGD2-GE dose-dependently induced cell death independently from cannabinoid receptors that was accompanied by PARP- and caspase 3-cleavage. In contrast to 2-AG, PGD2-GE failed to induce significant ROS formation in HSCs, and depletion of membrane cholesterol did not rescue HSCs from PGD2-GE-induced apoptosis. These findings indicate differential engagement of initial intracellular signaling pathways by 2-AG and its COX-2-derived metabolite PGD2-GE, but similar final cell death pathways. Other PG-GEs, such as PGE2-or PGF2α-GE did not induce apoptosis in HSCs. Primary rat hepatocytes were mainly resistant against 2-AG- and PGD2-GE-induced apoptosis. HSCs, but not hepatocytes were able to metabolize 2-AG to PGD2-GE. As a proof of principle, HSCs from COX-2(-/-) mice lacked PDG2-GE production after 2-AG treatment. Accordingly, COX-2(-/-) HSCs were resistant against 2-AG-induced apoptosis. In conclusion, the divergent expression of COX-2 in HSCs and hepatocytes contributes to the different susceptibility of these cell types towards 2-AG-induced cell death due to the generation of pro-apoptotic PGD2-GE by COX-2 in HSCs. Modulation of COX-2-driven metabolization of 2-AG may provide a novel physiological concept allowing the specific targeting of HSCs in liver fibrosis.
Assuntos
Apoptose/fisiologia , Ácidos Araquidônicos/administração & dosagem , Ciclo-Oxigenase 2/metabolismo , Endocanabinoides/administração & dosagem , Glicerídeos/administração & dosagem , Células Estreladas do Fígado/fisiologia , Hepatócitos/fisiologia , Animais , Apoptose/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Endocanabinoides/metabolismo , Células Estreladas do Fígado/citologia , Células Estreladas do Fígado/efeitos dos fármacos , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Espécies Reativas de OxigênioRESUMO
BACKGROUND: Type II shell evolution has recently been identified as a microscopic cause for nuclear shape coexistence. PURPOSE: Establish a low-lying rotational band in ^{96}Zr. METHODS: High-resolution inelastic electron scattering and a relative analysis of transition strengths are used. RESULTS: The B(E2;0_{1}^{+}â2_{2}^{+}) value is measured and electromagnetic decay strengths of the 2_{2}^{+} state are deduced. CONCLUSIONS: Shape coexistence is established for ^{96}Zr. Type II shell evolution provides a systematic and quantitative mechanism to understand deformation at low excitation energies.
RESUMO
Live imaging of mitochondrial function is crucial to understand the important role played by these organelles in a wide range of diseases. The mitochondrial redox potential is a particularly informative measure of mitochondrial function, and can be monitored using the endogenous green fluorescence of oxidized mitochondrial flavoproteins. Here, we have observed flavoprotein fluorescence in the exposed murine cerebral cortex in vivo using confocal imaging; the mitochondrial origin of the signal was confirmed using agents known to manipulate mitochondrial redox potential. The effects of cerebral oxygenation on flavoprotein fluorescence were determined by manipulating the inspired oxygen concentration. We report that flavoprotein fluorescence is sensitive to reductions in cortical oxygenation, such that reductions in inspired oxygen resulted in loss of flavoprotein fluorescence with the exception of a preserved 'halo' of signal in periarterial regions. The findings are consistent with reports that arteries play an important role in supplying oxygen directly to tissue in the cerebral cortex, maintaining mitochondrial function.
Assuntos
Córtex Cerebral/metabolismo , Flavoproteínas/análise , Mitocôndrias/fisiologia , Oxigênio/metabolismo , Animais , Hipóxia Celular , Fluorescência , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Tissue oxygen tension is the partial pressure of oxygen within the interstitial space of an organ bed. As it represents the balance between local oxygen delivery and consumption at any given time, it offers a ready monitoring capability to assess the adequacy of tissue perfusion relative to local demands. This review covers the various methodologies used to measure tissue oxygen tension, describes the underlying physiological and pathophysiological principles, and summarizes human and laboratory data published to date.
Assuntos
Monitorização Intraoperatória/instrumentação , Monitorização Intraoperatória/métodos , Oximetria/instrumentação , Oximetria/métodos , Consumo de Oxigênio/fisiologia , Oxigênio/metabolismo , Gasometria , Humanos , Pressão Parcial , Fluxo Sanguíneo RegionalRESUMO
Cardiovascular resuscitation is a cornerstone of critical care practice. Experimental advances have increased our understanding of the role of the microcirculation in shock states and the development of multi-organ failure. Strategies that target the microcirculation in such conditions, while theoretically appealing, have not yet been shown to impact upon clinical outcomes. This review outlines the current understanding of microcirculatory dysfunction in septic, cardiogenic, and hypovolaemic shock and outlines available treatments and strategies with reference to their effects upon the microcirculation.
Assuntos
Cuidados Críticos/métodos , Microcirculação/fisiologia , Ressuscitação/métodos , Choque/fisiopatologia , Choque/terapia , HumanosRESUMO
BACKGROUND: The accuracy of oxygen consumption measurement by indirect calorimeters is poorly validated in mechanically ventilated intensive care patients where multiple confounders exist. This study sought to compare the Medgraphics Ultima (MGU) and Deltatrac II (DTII) devices, and the Douglas bag (DB) technique in mechanically ventilated patients at rest. METHODS: Prospective comparison of oxygen consumption measurement using three indirect calorimetry techniques in stable, resting mechanically ventilated patients at rest. Oxygen consumption (VO2), carbon dioxide production (VCO2), resting energy expenditure (REE), and respiratory quotient (RQ) were recorded breath-by-breath by the MGU over a 30-75 min period. During this time, simultaneous measurements were taken using the DTII, the DB, or both. RESULTS: While there was no systematic error (bias) between measurements made by the three techniques (VO2: MGU vs DTII 3.6%, MGU vs DB 3.3%), the limits of agreement were wide (VO2: MGU vs DTII 33%, MGU vs DB 54%). CONCLUSIONS: Resting oxygen consumption values in stable mechanically ventilated patients measured by the three techniques showed acceptable bias but poor precision. There is an important clinical and research need to develop new indirect calorimeters specifically tailored to measure oxygen consumption during mechanical ventilation.
Assuntos
Calorimetria Indireta/instrumentação , Calorimetria Indireta/métodos , Cuidados Críticos/métodos , Metabolismo/fisiologia , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Idoso , Idoso de 80 Anos ou mais , Dióxido de Carbono/metabolismo , Metabolismo Energético/fisiologia , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Respiração ArtificialRESUMO
The first step in attachment of Chlamydia to host cells is thought to involve reversible binding to host heparan sulfate proteoglycans (HSPGs), polymers of variably sulfated repeating disaccharide units coupled to diverse protein backbones. However, the key determinants of HSPG structure that are involved in Chlamydia binding are incompletely defined. A previous genome-wide Drosophila RNAi screen suggested that the level of HSPG 6-O sulfation rather than the identity of the proteoglycan backbone maybe a critical determinant for binding. Here, we tested in mammalian cells whether SULF1 or SULF2, human endosulfatases, which remove 6-O sulfates from HSPGs, modulate Chlamydia infection. Ectopic expression of SULF1 or SULF2 in HeLa cells, which decreases cell surface HSPG sulfation, diminished C. muridarum binding and decreased vacuole formation. ShRNA depletion of endogenous SULF2 in a cell line that primarily expresses SULF2 augmented binding and increased vacuole formation. C. muridarum infection of diverse cell lines resulted indownregulation of SULF2 mRNA. In a murine model of acute pneumonia, mice genetically deficient in both endosulfatases or in SULF2 alone demonstrated increased susceptibility to C. muridarum lung infection. Collectively, these studies demonstrate that the level of HSPG 6-O sulfation is a critical determinant of C. muridarum infection in vivo and that 6-O endosulfatases are previously unappreciated modulators of microbial pathogenesis.
Assuntos
Aderência Bacteriana , Infecções por Chlamydia/imunologia , Chlamydia muridarum/imunologia , Heparitina Sulfato/metabolismo , Sulfotransferases/imunologia , Animais , Infecções por Chlamydia/microbiologia , Chlamydia muridarum/crescimento & desenvolvimento , Modelos Animais de Doenças , Suscetibilidade a Doenças , Células HeLa , Humanos , Camundongos , Camundongos Knockout , Pneumonia Bacteriana/imunologia , Pneumonia Bacteriana/microbiologia , Sulfatases/deficiência , Sulfatases/imunologia , Sulfotransferases/deficiência , Sulfotransferases/metabolismoRESUMO
Some insect herbivores sequester plant secondary metabolites (PSMs) for their own defense, raising the interesting possibility that grazing herbivores are defended by combinations of PSMs from different plant species. In this study, we tested the hypothesis that the grazing caterpillar, Grammia incorrupta, deters the ant, Aphaenogaster cockerelli, by eating a mixture of plants containing iridoid glycosides (IGs) and those containing pyrrolizidine alkaloids (PAs), and that this deterrence is greater than that attained by eating either plant alone. This hypothesis was tested against the non-mutually exclusive hypothesis that mixing plants containing PAs with those containing IGs improves growth performance. Caterpillar survival and growth were measured on three experimental diets: a PA plant, an IG plant, and a mixture of the two. We measured the degree of deterrence associated with these, and an additional experimental diet devoid of PSMs at naturally occurring A. cockerelli nests. Caterpillars fed both plants gained more mass than those fed either plant alone, but took longer to develop. These differences were not caused by diet-based variation in growth efficiency, but by eating more food when offered the mixed-plant diet relative to single-plant diets. The mixed diet was shown to provide deterrence to ants, whereas caterpillars fed single-plant diets were not significantly more deterrent than caterpillars that had eaten the PSM-free diet. We hypothesize that enhanced defense results from increased food consumption in response to multiple plant species, perhaps leading to greater PSM sequestration. Through this mechanism, bottom-up and top-down effects may mutually reinforce the grazing dietary strategy.
Assuntos
Formigas , Comportamento Alimentar/fisiologia , Herbivoria , Mariposas/fisiologia , Plantas Tóxicas/química , Animais , Dieta , Glicosídeos Iridoides/química , Larva/química , Larva/fisiologia , Mariposas/química , Comportamento Predatório , Alcaloides de Pirrolizidina/químicaRESUMO
The number of people travelling to malaria-endemic countries continues to increase, and malaria remains the commonest cause of serious imported infection in non-endemic areas. Severe malaria, mostly caused by Plasmodium falciparum, often requires intensive care unit (ICU) admission and can be complicated by cerebral malaria, respiratory distress, acute kidney injury, bleeding complications, and co-infection. The mortality from imported malaria remains significant. This article reviews the manifestations, complications and principles of management of severe malaria as relevant to critical care clinicians, incorporating recent studies of anti-malarial and adjunctive treatment. Effective management of severe malaria includes prompt diagnosis and early institution of effective anti-malarial therapy, recognition of complications, and appropriate supportive management in an ICU. All cases should be discussed with a specialist unit and transfer of the patient considered.