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1.
Front Psychiatry ; 15: 1370256, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38818025

RESUMO

Suicide in children is a significant and growing problem. The "zero suicide" framework (ZSF) is one approach to suicide prevention used in health services for adults and children. This paper reports on the introduction of the first suicide prevention pathway (SPP) based on ZSF at a Child and Youth Mental Health Service (CYMHS) in Australia. It begins by describing the adaptations made to elements of the SPP originally designed for adults to meet the needs of children. Lessons learned in applying the SPP in the service are then discussed. The aim is to inform and improve practice in the use of zero suicide approaches in child and youth mental health settings in Australia and worldwide.

2.
MicroPubl Biol ; 20242024.
Artigo em Inglês | MEDLINE | ID: mdl-38725941

RESUMO

Burkholderia species belonging to the pseudomallei group include significant human and animal pathogens as well as the non-pathogenic species Burkholderia thailandensis . These bacteria co-opt the host cell machinery for their replication and spread between host cells. Thus, it is of interest to understand the structural features of these cells that contribute to host cell colonization and virulence. This study provides high-resolution cryo-electron tomograms of stationary phase Burkholderia thailandensis . It reveals the presence of compact nucleoids and storage granules, as well as examples of the type III secretion system and chemoreceptor arrays. The data can be used to investigate the near-atomic structure of stationary-phase bacterial macromolecules, such as ribosomes.

4.
Shoulder Elbow ; 16(2): 129-144, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38655415

RESUMO

Background: This systematic review aims to comprehensively summarise and present the available evidence for the treatment of primary acromioclavicular joint (ACJ) osteoarthritis (OA). Methods: Five databases were searched for studies investigating the management of ACJ OA. Included were studies with participants with clinical/radiological signs of primary ACJ OA, an intervention and included a functional outcome measure. Results: Forty-eight studies were included. Treatments consisted of physiotherapy (n = 1 study), medical only (n = 11) and operative management (n = 36). Operative studies included five comparative trials - physiotherapy versus surgery (n = 1) and open versus arthroscopic resection (n = 4). A total of 1902 shoulders were treated for ACJ OA, mean age (51 years), 58% male and mean follow-up (28.5 months). Treatment with injection showed a mean improvement of 50% in pain levels at follow-up (mean = 7.5 months). The commonest surgical procedure was arthroscopic excision of the distal clavicle and operative studies averaged 6 months of conservative management and a mean functional outcome of 87.8%. Conclusion: Studies varied in indication, intervention and quality but it did not provide evidence that both non-operative and operative interventions are effective. There was no significant difference between open or arthroscopic distal clavicle excision (DCE). Participants having between 0.5 and 2 cm of clavicle excised had good outcomes and those requiring concomitant shoulder procedures had similarly good outcomes.

5.
Infect Immun ; 92(2): e0051523, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38206007

RESUMO

Rickettsia parkeri is a pathogen of public health concern and transmitted by the Gulf Coast tick, Amblyomma maculatum. Rickettsiae are obligate intracellular bacteria that enter and replicate in diverse host cells. Rickettsial outer membrane protein B (OmpB) functions in bacterial adhesion, invasion, and avoidance of cell-autonomous immunity in mammalian cell infection, but the function of OmpB in arthropod infection is unknown. In this study, the function of R. parkeri OmpB was evaluated in the tick host. R. parkeri wild-type and R. parkeri ompBSTOP::tn (non-functional OmpB) were capillary fed to naïve A. maculatum ticks to investigate dissemination in the tick and transmission to vertebrates. Ticks exposed to R. parkeri wild-type had greater rickettsial loads in all organs than ticks exposed to R. parkeri ompBSTOP::tn at 12 h post-capillary feeding and after 1 day of feeding on host. In rats that were exposed to R. parkeri ompBSTOP::tn-infected ticks, dermal inflammation at the bite site was less compared to R. parkeri wild-type-infected ticks. In vitro, R. parkeri ompBSTOP::tn cell attachment to tick cells was reduced, and host cell invasion of the mutant was initially reduced but eventually returned to the level of R. parkeri wild-type by 90 min post-infection. R. parkeri ompBSTOP::tn and R. parkeri wild-type had similar growth kinetics in the tick cells, suggesting that OmpB is not essential for R. parkeri replication in tick cells. These results indicate that R. parkeri OmpB functions in rickettsial attachment and internalization to tick cells and pathogenicity during tick infection.


Assuntos
Ixodidae , Rickettsia , Carrapatos , Ratos , Animais , Carrapatos/microbiologia , Ixodidae/microbiologia , Proteínas de Membrana , Mamíferos
6.
Mol Biol Cell ; 34(10): ar103, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37531263

RESUMO

Trypanosoma brucei, the causative agent of African sleeping sickness, uses its flagellum for movement, cell division, and signaling. The flagellum is anchored to the cell body membrane via the flagellum attachment zone (FAZ), a complex of proteins, filaments, and microtubules that spans two membranes with elements on both flagellum and cell body sides. How FAZ components are carried into place to form this complex is poorly understood. Here, we show that the trypanosome-specific kinesin KIN-E is required for building the FAZ in bloodstream-form parasites. KIN-E is localized along the flagellum with a concentration at its distal tip. Depletion of KIN-E by RNAi rapidly inhibits flagellum attachment and leads to cell death. A detailed analysis reveals that KIN-E depletion phenotypes include failure in cytokinesis completion, kinetoplast DNA missegregation, and transport vesicle accumulation. Together with previously published results in procyclic form parasites, these data suggest KIN-E plays a critical role in FAZ assembly in T. brucei.


Assuntos
Trypanosoma brucei brucei , Trypanosoma brucei brucei/metabolismo , Cinesinas/metabolismo , Citocinese , Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Flagelos/metabolismo , Proteínas de Protozoários/metabolismo
7.
Mol Biol Cell ; 34(9): ed2, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37486892
8.
Opt Lett ; 48(14): 3649-3652, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37450716

RESUMO

Highly efficient coherent beam combining (CBC) of two very-high-power optical amplifiers (VHPOA) with applications to long-range FSO communications such as ground-to-space feeder links is presented. The CBC setup is designed to minimize the telecom signal degradation, with a polarization beam splitter used to minimize the power fluctuations and to control the output polarization state of the beam. The system delivers 80 W output power and is proven to be compatible with 25 Gb/s telecom signals with a less than 1 dB power penalty.

9.
Biosensors (Basel) ; 13(6)2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37366941

RESUMO

Neurotransmitter release is important to study in order to better understand neurological diseases and treatment approaches. Serotonin is a neurotransmitter known to play key roles in the etiology of neuropsychiatric disorders. Fast-scan cyclic voltammetry (FSCV) has enabled the detection of neurochemicals, including serotonin, on a sub-second timescale via the well-established carbon fiber microelectrode (CFME). However, poor chronic stability and biofouling, i.e., the adsorption of interferent proteins to the electrode surface upon implantation, pose challenges in the natural physiological environment. We have recently developed a uniquely designed, freestanding, all-diamond boron-doped diamond microelectrode (BDDME) for electrochemical measurements. Key potential advantages of the device include customizable electrode site layouts, a wider working potential window, improved stability, and resistance to biofouling. Here, we present a first report on the electrochemical behavior of the BDDME in comparison with CFME by investigating in vitro serotonin (5-HT) responses with varying FSCV waveform parameters and biofouling conditions. While the CFME delivered lower limits of detection, we also found that BDDMEs showed more sustained 5-HT responses to increasing or changing FSCV waveform-switching potential and frequency, as well as to higher analyte concentrations. Biofouling-induced current reductions were significantly less pronounced at the BDDME when using a "Jackson" waveform compared to CFMEs. These findings are important steps towards the development and optimization of the BDDME as a chronically implanted biosensor for in vivo neurotransmitter detection.


Assuntos
Incrustação Biológica , Diamante , Microeletrodos , Serotonina , Boro , Fibra de Carbono , Neurotransmissores
10.
Cochrane Database Syst Rev ; 3: CD008579, 2023 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-36866917

RESUMO

BACKGROUND: The morbidity and socioeconomic costs of fractures are considerable. The length of time to healing is an important factor in determining a person's recovery after a fracture. Ultrasound may have a therapeutic role in reducing the time to union after fracture by stimulating osteoblasts and other bone-forming proteins. This is an update of a review previously published in February 2014.   OBJECTIVES: To assess the effects of low-intensity ultrasound (LIPUS), high-intensity focused ultrasound (HIFUS) and extracorporeal shockwave therapies (ECSW) as part of the treatment of acute fractures in adults.  SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase (1980 to March 2022), Orthopaedic Proceedings, trial registers and reference lists of articles. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs including participants over 18 years of age with acute fractures (complete or stress fractures) treated with either LIPUS, HIFUS or ECSW versus a control or placebo-control. DATA COLLECTION AND ANALYSIS: We used standard methodology expected by Cochrane. We collected data for the following critical outcomes: participant-reported quality of life, quantitative functional improvement, time to return to normal activities, time to fracture union, pain, delayed or non-union of fracture. We also collected data for treatment-related adverse events. We collected data in the short term (up to three months after surgery) and in the medium term (later than three months after surgery).   MAIN RESULTS: We included 21 studies, involving 1543 fractures in 1517 participants; two studies were quasi-RCTs. Twenty studies tested LIPUS and one trial tested ECSW; no studies tested HIFUS. Four studies did not report any of the critical outcomes. All studies had unclear or high risk of bias in at least one domain. The certainty of the evidence was downgraded for imprecision, risk of bias and inconsistency. LIPUS versus control (20 studies, 1459 participants) We found very low-certainty evidence for the effect of LIPUS on Health-related quality of life (HRQoL) measured by SF-36 at up to one year after surgery for lower limb fractures (mean difference (MD) 0.06, 95% confidence interval (CI) -3.85 to 3.97, favours LIPUS; 3 studies, 393 participants). This result was compatible with a clinically important difference of 3 units with both LIPUS or control. There may be little to no difference in time to return to work after people had complete fractures of the upper or lower limbs (MD 1.96 days, 95% CI -2.13 to 6.04, favours control; 2 studies, 370 participants; low-certainty evidence).  There is probably little or no difference in delayed union or non-union up to 12 months after surgery (RR 1.25, 95% CI 0.50 to 3.09, favours control; 7 studies, 746 participants; moderate-certainty evidence). Although data for delayed and non-union included both upper and lower limbs, we noted that there were no incidences of delayed or non-union in upper limb fractures. We did not pool data for time to fracture union (11 studies, 887 participants; very low-certainty evidence) because of substantial statistical heterogeneity which we could not explain. In upper limb fractures, MDs ranged from 0.32 to 40 fewer days to fracture union with LIPUS. In lower limb fractures, MDs ranged from 88 fewer days to 30 more days to fracture union. We also did not pool data for pain experienced at one month after surgery in people with upper limb fractures (2 studies, 148 participants; very low-certainty evidence) because of substantial unexplained statistical heterogeneity. Using a 10-point visual analogue scale, one study reported less pain with LIPUS (MD -1.7, 95% CI -3.03 to -0.37; 47 participants), and the effect was less precise in the other study (MD -0.4, 95% CI -0.61 to 0.53; 101 participants). We found little or no difference in skin irritation (a possible treatment-related adverse event) between groups but judged the certainty of the evidence from this small study to be very low (RR 0.94, 95% CI 0.06 to 14.65; 1 study, 101 participants). No studies reported data for functional recovery. Data for treatment adherence were inconsistently reported across studies, but was generally described to be good. Data for costs were reported for one study, with higher direct costs, as well as combined direct and indirect costs, for LIPUS use. ECSW versus control (1 study, 56 participants) We are uncertain whether ECSW reduces pain at 12 months after surgery in fractures of the lower limb (MD -0.62, 95% CI -0.97 to -0.27, favours ECSW); the difference between pain scores was unlikely to be clinically important, and the certainty of the evidence was very low. We are also uncertain of the effect of ECSW on delayed or non-union at 12 months because the certainty of this evidence is very low (RR 0.56, 95% CI 0.15 to 2.01; 1 study, 57 participants). There were no treatment-related adverse events. This study reported no data for HRQoL, functional recovery, time to return to normal activities, or time to fracture union. In addition, no data were available for adherence or cost. AUTHORS' CONCLUSIONS: We were uncertain of the effectiveness of ultrasound and shock wave therapy for acute fractures in terms of patient-reported outcome measures (PROMS), for which few studies reported data. It is probable that LIPUS makes little or no difference to delayed union or non-union. Future trials should be double-blind, randomised, placebo-controlled trials recording validated PROMs and following up all trial participants. Whilst time to union is difficult to measure, the proportion of participants achieving clinical and radiographic union at each follow-up point should be ascertained, alongside adherence with the study protocol and cost of treatment in order to better inform clinical practice.


Assuntos
Tratamento por Ondas de Choque Extracorpóreas , Fraturas de Estresse , Ondas de Choque de Alta Energia , Adulto , Humanos , Adolescente , Ultrassonografia , Dor , Ensaios Clínicos Controlados Aleatórios como Assunto
11.
Curr Opin Microbiol ; 71: 102241, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36442349

RESUMO

Manipulation of the host cell plasma membrane is critical during infection by intracellular bacterial pathogens, particularly during bacterial entry into and exit from host cells. To manipulate host cells, bacteria deploy secreted proteins that modulate or modify host cell components. Here, we review recent advances that suggest common themes by which bacteria manipulate the host cell plasma membrane. One theme is that bacteria use diverse strategies to target or influence host cell plasma membrane composition and shape. A second theme is that bacteria take advantage of host cell plasma membrane-associated pathways such as signal transduction, endocytosis, and exocytosis. Future investigation into how bacterial and host factors contribute to plasma membrane manipulation by bacterial pathogens will reveal new insights into pathogenesis and fundamental principles of plasma membrane biology.


Assuntos
Bactérias , Endocitose , Bactérias/genética , Bactérias/metabolismo , Membrana Celular/metabolismo , Transdução de Sinais , Interações Hospedeiro-Patógeno/fisiologia
12.
Front Psychiatry ; 13: 910896, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36090378

RESUMO

Cognitive impairment is a common and pervasive feature of etiologically diverse disorders of the central nervous system, and a target indication for a growing number of symptomatic and disease modifying drugs. Remotely acquired digital endpoints have been recognized for their potential in providing frequent, real-time monitoring of cognition, but their ultimate value will be determined by the reliability and sensitivity of measurement in the populations of interest. To this end, we describe initial validation of remote self-administration of cognitive tests within a regulatorily compliant tablet-based platform. Participants were 61 older adults (age 55+), including 20 individuals with subjective cognitive decline (SCD). To allow comparison between remote (in-home) and site-based testing, participants completed 2 testing sessions 1 week apart. Results for three of four cognitive domains assessed demonstrated equivalence between remote and site-based tests, with high cross-modality ICCs (absolute agreement) for Symbol Coding (ICC = 0.75), Visuospatial Working Memory (ICC = 0.70) and Verbal Fluency (ICC > 0.73). Group differences in these domains were significant and reflected sensitivity to objective cognitive impairment in the SCD group for both remote and site-based testing (p < 0.05). In contrast, performance on tests of verbal episodic memory suggested inflated performance during unmonitored testing and indicate reliable use of remote cognitive assessments may depend on the construct, as well as the population being tested.

13.
Nat Commun ; 13(1): 3608, 2022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35750685

RESUMO

Many key insights into actin regulation have been derived through examining how microbial pathogens intercept the actin cytoskeleton during infection. Mycobacterium marinum, a close relative of the human pathogen Mycobacterium tuberculosis, polymerizes host actin at the bacterial surface to drive intracellular movement and cell-to-cell spread during infection. However, the mycobacterial factor that commandeers actin polymerization has remained elusive. Here, we report the identification and characterization of the M. marinum actin-based motility factor designated mycobacterial intracellular rockets A (MirA), which is a member of the glycine-rich PE_PGRS protein family. MirA contains an amphipathic helix to anchor into the mycobacterial outer membrane and, surprisingly, also the surface of host lipid droplet organelles. MirA directly binds to and activates the host protein N-WASP to stimulate actin polymerization through the Arp2/3 complex, directing both bacterial and lipid droplet actin-based motility. MirA is dissimilar to known N-WASP activating ligands and may represent a new class of microbial and host actin regulator. Additionally, the MirA-N-WASP interaction represents a model to understand how the enigmatic PE_PGRS proteins contribute to mycobacterial pathogenesis.


Assuntos
Mycobacterium marinum , Mycobacterium tuberculosis , Actinas/metabolismo , Proteínas de Bactérias/metabolismo , Parede Celular/metabolismo , Glicina/metabolismo , Humanos , Mycobacterium tuberculosis/metabolismo
14.
Nat Commun ; 13(1): 3656, 2022 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-35760786

RESUMO

Rickettsia species of the spotted fever group are arthropod-borne obligate intracellular bacteria that can cause mild to severe human disease. These bacteria invade host cells, replicate in the cell cytosol, and spread from cell to cell. To access the host cytosol and avoid immune detection, they escape membrane-bound vacuoles by expressing factors that disrupt host membranes. Here, we show that a patatin-like phospholipase A2 enzyme (Pat1) facilitates Rickettsia parkeri infection by promoting escape from host membranes and cell-cell spread. Pat1 is important for infection in a mouse model and, at the cellular level, is crucial for efficiently escaping from single and double membrane-bound vacuoles into the host cytosol, and for avoiding host galectins that mark damaged membranes. Pat1 is also important for avoiding host polyubiquitin, preventing recruitment of autophagy receptor p62, and promoting actin-based motility and cell-cell spread.


Assuntos
Sistemas de Transporte de Aminoácidos/metabolismo , Infecções por Rickettsia , Rickettsia , Simportadores/metabolismo , Animais , Citosol/microbiologia , Camundongos , Fosfolipases/metabolismo , Rickettsia/genética , Rickettsia/metabolismo , Infecções por Rickettsia/microbiologia
16.
Mol Biol Cell ; 33(8): ar70, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35594178

RESUMO

Cell-cell fusion is important for biological processes including fertilization, development, immunity, and microbial pathogenesis. Bacteria in the pseudomallei group of the Burkholderia species, including B. thailandensis, spread between host cells by inducing cell-cell fusion. Previous work showed that B. thailandensis-induced cell-cell fusion requires intracellular bacterial motility and a bacterial protein secretion apparatus called the type VI secretion system-5 (T6SS-5), including the T6SS-5 protein VgrG5. However, the cellular-level mechanism of and T6SS-5 proteins important for bacteria-induced cell-cell fusion remained incompletely described. Using live-cell imaging, we found bacteria used actin-based motility to push on the host cell plasma membrane to form plasma membrane protrusions that extended into neighboring cells. Then, membrane fusion occurred within membrane protrusions either proximal to the bacterium at the tip or elsewhere within protrusions. Expression of VgrG5 by bacteria within membrane protrusions was required to promote cell-cell fusion. Furthermore, a second predicted T6SS-5 protein, TagD5, was also required for cell-cell fusion. In the absence of VgrG5 or TagD5, bacteria in plasma membrane protrusions were engulfed into neighboring cells. Our results suggest that the T6SS-5 effectors VgrG5 and TagD5 are secreted within membrane protrusions and act locally to promote membrane fusion.


Assuntos
Burkholderia , Sistemas de Secreção Tipo VI , Proteínas de Bactérias/metabolismo , Burkholderia/metabolismo , Fusão Celular , Membrana Celular/metabolismo , Sistemas de Secreção Tipo VI/metabolismo
17.
Mol Biol Cell ; 33(4): ed1, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35319238
18.
J Spec Oper Med ; 21(4): 63-65, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34969128

RESUMO

BACKGROUND: We sought to test whether Celox topical hemostatic dressing (Medtrade Products) would maintain hemostasis in extended use. METHODS: An anesthetized swine underwent bilateral arteriotomies and treatment with topical hemostatic dressings in line with the Kheirabadi method. The dressings were covered with standard field dressings, and these were visually inspected for bleeding every 2 hours until 8 hours, when the swine was euthanized. RESULTS: There was no evidence of rebleeding at any point up to and including 8 hours. The Celox dressings maintained hemostasis in extended use. CONCLUSION: Celox topical hemostatic dressing is effective for extended use and maintains hemostasis. It should be considered for use in situations in which evacuation and definitive care may be delayed.


Assuntos
Hemostáticos , Animais , Bandagens , Modelos Animais de Doenças , Hemostasia , Técnicas Hemostáticas , Hemostáticos/uso terapêutico , Suínos
19.
Artigo em Inglês | MEDLINE | ID: mdl-34682380

RESUMO

This study explored the experiences of healthcare consumers who had recently attempted suicide, and their carers, following placement on a Suicide Prevention Pathway based on the Zero Suicide framework. Qualitative interviews were conducted with 10 consumers and 5 carers using a semi-structured interview schedule. Interviews were transcribed and thematic analysis was applied to identify prominent themes and sub-themes. Three interrelated themes were identified. The first theme was 'Feeling safe and valued' with the associated sub-theme pertaining to perceived stigmatizing treatment and self-stigma. The second was 'Intersection of consumer and staff/organizational needs' with a related sub-theme of time pressure and reduced self-disclosure. The final theme was 'Importance of the 'whole picture', highlighting the relevance of assessing and addressing psychosocial factors when planning for consumer recovery. Overall, consumers and their carers reported a favorable experience of the Suicide Prevention Pathway; however, there were several areas identified for improvement. These included reconciling the time-pressures of a busy health service system, ensuring consumers and carers feel their psychosocial concerns are addressed, and ensuring that adequate rapport is developed. Key to this is ensuring consumers feel cared for and reducing perceptions of stigma.


Assuntos
Cuidadores , Estigma Social , Atenção à Saúde , Humanos , Pesquisa Qualitativa , Tentativa de Suicídio
20.
Elife ; 102021 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-34423779

RESUMO

Arthropod-borne rickettsial pathogens cause mild and severe human disease worldwide. The tick-borne pathogen Rickettsia parkeri elicits skin lesions (eschars) and disseminated disease in humans; however, inbred mice are generally resistant to infection. We report that intradermal infection of mice lacking both interferon receptors (Ifnar1-/-;Ifngr1-/-) with as few as 10 R. parkeri elicits eschar formation and disseminated, lethal disease. Similar to human infection, eschars exhibited necrosis and inflammation, with bacteria primarily found in leukocytes. Using this model, we find that the actin-based motility factor Sca2 is required for dissemination from the skin to internal organs, and the outer membrane protein OmpB contributes to eschar formation. Immunizing Ifnar1-/-;Ifngr1-/- mice with sca2 and ompB mutant R. parkeri protects against rechallenge, revealing live-attenuated vaccine candidates. Thus, Ifnar1-/-;Ifngr1-/- mice are a tractable model to investigate rickettsiosis, virulence factors, and immunity. Our results further suggest that discrepancies between mouse and human susceptibility may be due to differences in interferon signaling.


Tick bites allow disease-causing microbes, including multiple species of Rickettsia bacteria, to pass from arthropods to humans. Being exposed to Rickettsia parkeri, for example, can cause a scab at the bite site, fever, headache and fatigue. To date, no vaccine is available against any of the severe diseases caused by Rickettsia species. Modelling human infections in animals could help to understand and combat these illnesses. R. parkeri is a good candidate for such studies, as it can give insight into more severe Rickettsia infections while being comparatively safer to handle. However, laboratory mice are resistant to this species of bacteria, limiting their use as models. To explore why this is the case, Burke et al. probed whether an immune mechanism known as interferon signalling protects laboratory rodents against R. parkeri. During infection, the immune system releases molecules called interferons that stick to 'receptors' at the surface of cells, triggering defense mechanisms that help to fight off an invader. Burke et al. injected R. parkeri into the skin of mice that had or lacked certain interferon receptors, showing that animals without two specific receptors developed scabs and saw the disease spread through their body. Further investigation showed that two R. parkeri proteins, known as OmpB or Sca2, were essential for the bacteria to cause skin lesions and damage internal organs. Burke et al. then used R. parkeri that lacked OmpB or Sca2 to test whether these modified, inoffensive microbes could act as 'vaccines'. And indeed, vulnerable laboratory mice which were first exposed to the mutant bacteria were then able to survive the 'normal' version of the microbe. Together, this work reveals that interferon signalling protects laboratory mice against R. parkeri infections. It also creates an animal model that can be used to study disease and vaccination.


Assuntos
Estudos de Associação Genética , Receptores de Interferon/deficiência , Receptores de Interferon/genética , Infecções por Rickettsia/imunologia , Animais , Medula Óssea , Feminino , Imunidade Inata , Inflamação , Listeria monocytogenes , Macrófagos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptor de Interferon alfa e beta/genética , Rickettsia , Infecções por Rickettsia/patologia , Carrapatos
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