Sidelobe Suppression Techniques for Near-Field Multistatic SAR.

Multirotor Unmanned Air Systems (UAS) represent a significant improvement in capability for Synthetic Aperture Radar (SAR) imaging when compared to traditional, fixed-wing, platforms. In particular, a swarm of UAS can generate significant measurement diversity through variation of spatial and frequency collections across an array of sensors. In such imaging schemes, the image formation step is challenging due to strong extended sidelobe; however, were this to be effectively managed, a dramatic increase in image quality is theoretically possible. Since 2015, QinetiQ have developed the RIBI system, which uses multiple UAS to perform short-range multistatic collections, and this requires novel near-field processing to mitigate the high sidelobes observed and form actionable imagery. This paper applies a number of algorithms to assess image reconstruction of simulated near-field multistatic SAR with an aim to suppress sidelobes observed in the RIBI system, investigating techniques including traditional SAR processing, regularised linear regression, compressive sensing. In these simulations presented, Elastic net, Orthogonal Matched Pursuit, and Iterative Hard Thresholding all show the ability to suppress sidelobes while preserving accuracy of scatterer RCS. This has also lead to a novel processing approach for reconstructing SAR images based on the observed Elastic net and Iterative Hard Thresholding performance, mitigating weaknesses to generate an improved combined approach. The relative strengths and weaknesses of the algorithms are discussed, as well as their application to more complex real-world imagery.

Vulvar and vestibulovaginal hemangiosarcoma in a cow: morphological and histopathological observations.

Background: Hemangiosarcoma is defined as the malignant mesenchymal neoplasm of endothelial cells. It is a common tumor affecting dogs and is very rare in cattle. Case description: A seven-year-old three months pregnant female Holstein Friesian cross-breed cow was presented with a history of a proliferating irregular dark red friable mass in the vulvar region for the past month. Findings/treatment and outcome: The surface of the mass had diffuse ecchymotic hemorrhages. Histopathological examination of the tissue biopsy specimen revealed unencapsulated, infiltrating neoplasm composed of numerous vascular channels with irregular borders surrounded by endothelial cells of variable sizes and shapes supported by a scanty fibrovascular stroma. Based on morphological and histopathological findings, the case was diagnosed as vulvar and vestibulovaginal hemangiosarcoma. The animal was culled due to the poor prognosis. Conclusion: To the best of our knowledge, this is the first report of vulvar and vestibulovaginal hemangiosarcoma in a cow.

Preparation for the next major incident: are we ready? Comparing major trauma centres and other hospitals.

OBJECTIVES: A major incident is any emergency requiring special arrangements by the emergency services. All hospitals are required by law to keep a major incident plan (MIP) detailing the response to such events. In 2006 and 2019, we assessed the preparedness and knowledge of key individuals in hospitals across England and found a substantial gap in responding to the MIP. In this report, we compare responses from doctors at major trauma centres (MTCs) and other hospitals (non-MTCs). METHODS: We identified trusts in England that received over 30 000 patients through the ED in the fourth quarter of 2016/2017. We contacted the on-call anaesthetic, emergency, general surgery and trauma and orthopaedic registrar at each location and asked three questions assessing their confidence in using their hospital's MIP: (1) Have you read your hospital's MIP? (2) Do you know where you can access your hospital's MIP guidelines? (3) Do you know what role you would play if an MIP came into effect while you are on call?We compared data from MTCs and non-MTCs using multinomial mixed proportional odds models. RESULTS: There was a modest difference between responses from individuals at MTCs and non-MTCs for question 2 (OR=2.43, CI=1.03 to 5.73, p=0.04) but no evidence of a difference between question 1 (OR=1.41, CI=0.55 to 3.63, p=0.47) and question 3 (OR=1.78, CI=0.86 to 3.69, p=0.12). Emergency medicine and anaesthetic registrars showed significantly higher preparedness and knowledge across all domains. No evidence of a systematic difference in specialty response by MTC or otherwise was identified. CONCLUSIONS: Confidence in using MIPs among specialty registrars in England remains low. Doctors at MTCs tended to be better prepared and more knowledgeable, but this effect was only marginally significant. We make several recommendations to improve education on major incidents.

Satisfaction and genital perception after orchiectomy for prostate cancer: does the technique matter? A randomized trial.

OBJECTIVES: Bilateral extracapsular or total orchiectomy (BEO) for prostate cancer is presumed to have psychological consequences after the surgery due to perception of an empty scrotum. Bilateral subcapsular orchiectomy (BSO) was designed to preserve perception of palpable testes. We compared the patients' satisfaction and genital perception following BEO and BSO. MATERIALS AND METHODS: Prostate cancer patients eligible for androgen deprivation therapy who opted for orchiectomy were enrolled in prospective randomized study. Patients with bleeding disorder or uncorrected coagulopathy, poor performance score, and psychiatric problems were excluded. Outlook to life and own health in-general, overall satisfaction to the procedure and genital perception was evaluated using modified Fugl-Meyer questionnaire (FMQ) which was administered before and after 3 months of the surgery. Patients were randomized to BEO and BSO groups at the time of surgery using block randomization. Primary outcome was to compare the genital perception of testicular loss and patients' satisfaction to BSO and BEO. Secondary outcomes included testosterone and PSA control, operative time, and complications. RESULTS: Total 35 patients were enrolled in each group which was comparable. There was no difference in PSA control at 3 months. Mean operative time and blood loss were significantly lesser in BEO group. FMQ score at 3 months did not show significant difference. Majority of the patients in both groups were satisfied with procedure and the aesthetic value of scrotum after surgery. However, 84% in BSO group did not feel that testes were removed on self-examination, as compared to 28% in BEO group. Majority patients in both groups did not report physical or psychological discomfort from change in scrotal content. CONCLUSIONS: Results showed that patients' satisfaction and genital perception following BSO and BEO were similar. Feeling of remaining intrascrotal contents after BSO did not had added psychological advantage in terms of perception of genitalia.

Preparation for the next major incident: are we ready? A 12-year update.

OBJECTIVES: A major incident is any emergency that requires special arrangements by the emergency services and generally involves a large number of people. Recent such events in England have included the Manchester Arena bombing and the Grenfell Tower disaster. Hospitals are required by law to keep a major incident plan (MIP) outlining the response to such an event. In a survey conducted in 2006 we found a substantial knowledge gap among key individuals that would be expected to respond to the enactment of an MIP. We set out to repeat this survey study and assess any improvement since our original report. METHODS: We identified NHS trusts in England that received more than 30 000 patients through the emergency department in the fourth quarter of the 2016/2017 period. We contacted the on-call anaesthetic, emergency, general surgery, and trauma and orthopaedic registrar at each location and asked each individual to answer a short verbal survey assessing their confidence in using their hospital's MIP. RESULTS: Of those eligible for the study, 62% were able to be contacted and consented to the study. In total 50% of respondents had read all or part of their hospital's MIP, 46.8% were confident that they knew where their plan was stored, and 36% knew the role they would play if a plan came into effect. These results show less confidence among middle-grade doctors compared with 2006. CONCLUSIONS: Confidence in using MIPs among specialty registrars in England is still low. In light of this, we make a number of recommendations designed to improve the education of hospital doctors in reacting to major incidents.

Comparative assessment of faecal diagnostics for detection and predictive modelling of endemic Fasciola hepatica infection in sheep and cattle on Australian farms.

The diagnosis, monitoring and flukicide efficacy testing of fasciolosis on-farm is reliant on non-terminal methods. The coproantigen ELISA (cELISA) has been recommended for diagnosis of fasciolosis and associated flukicide efficacy testing as an alternative to fluke egg counts for monitoring parasitism. Recently experimental multi-age infections have suggested that the reliability of efficacy results can be improved by a second cELISA testing at 6 weeks post-treatment (wpt) in addition to the generally accepted 1 wpt. A field study was conducted to determine the suitability of faecal fluke egg counts (FFEC) and cELISA as diagnostic, drug efficacy testing and epidemiological tools on Australian sheep and cattle farms. Faecal samples from sheep and/or cattle on three endemic farms were taken at monthly intervals for 12 months and examined by both methods. Normal farm management was maintained during the study period and opportunistic efficacy testing, in line with each farm's normal flukicide management was undertaken. Additionally, the suitability of the Ollerenshaw Index as a predictive model for fasciolosis under Australian conditions was examined. While both diagnostics demonstrated their value in the farm environment, the current data demonstrate a distinct and significant increase in diagnostic sensitivity for epidemiological studies by using the two tests in parallel. The agreement between the two diagnostics was found to be higher in cattle, despite the poor sensitivity of FFEC in this species. Similar levels of agreement between the two tests were demonstrated at both sheep properties, regardless of the marked difference in the intensity of F. hepatica challenge. Linear regression models demonstrated the results of the two diagnostics utilized in parallel were explained substantially (R2 = 0.91) as were series data (R2 = 0.88) when the respective models were fitted. In contrast, the fitted models for FFEC (R2 = 0.54) and cELISA (R2 = 0.58) were poor explanations for test outcomes. The outcomes of these models support previous findings that suggest that the two diagnostic tests are best utilized together, particularly in parallel. The application of the Ollerenshaw Index to Australian conditions requires further investigation.

Comparative assessment of faecal diagnostics for detection and predictive modelling of endemic Fasciola hepatica infection in sheep and cattle on Australian farms.

The diagnosis, monitoring and flukicide efficacy testing of fasciolosis on-farm is reliant on non-terminal methods. The coproantigen ELISA (cELISA) has been recommended for diagnosis of fasciolosis and associated flukicide efficacy testing as an alternative to fluke egg counts for monitoring parasitism. Recently experimental multi-age infections have suggested that the reliability of efficacy results can be improved by a second cELISA testing at 6 weeks post-treatment (wpt) in addition to the generally accepted 1 wpt. A field study was conducted to determine the suitability of faecal fluke egg counts (FFEC) and cELISA as diagnostic, drug efficacy testing and epidemiological tools on Australian sheep and cattle farms. Faecal samples from sheep and/or cattle on three endemic farms were taken at monthly intervals for 12 months and examined by both methods. Normal farm management was maintained during the study period and opportunistic efficacy testing, in line with each farm's normal flukicide management was undertaken. Additionally, the suitability of the Ollerenshaw Index as a predictive model for fasciolosis under Australian conditions was examined. While both diagnostics demonstrated their value in the farm environment, the current data demonstrate a distinct and significant increase in diagnostic sensitivity for epidemiological studies by using the two tests in parallel. The agreement between the two diagnostics was found to be higher in cattle, despite the poor sensitivity of FFEC in this species. Similar levels of agreement between the two tests were demonstrated at both sheep properties, regardless of the marked difference in the intensity of F. hepatica challenge. Linear regression models demonstrated the results of the two diagnostics utilized in parallel were explained substantially (R2 = 0.91) as were series data (R2 = 0.88) when the respective models were fitted. In contrast, the fitted models for FFEC (R2 = 0.54) and cELISA (R2 = 0.58) were poor explanations for test outcomes. The outcomes of these models support previous findings that suggest that the two diagnostic tests are best utilized together, particularly in parallel. The application of the Ollerenshaw Index to Australian conditions requires further investigation.

Comparison between a fixed-dose contrast protocol and a weight-based contrast dosing protocol in abdominal CT.

AIM: To compare a fixed-dose intravenous iodinated contrast medium protocol with weight-based dosing protocols for abdominal computed tomography (CT). MATERIALS AND METHODS: Fifty patients were scanned using a fixed-dose protocol, 50 patients were scanned using a full-dose weight-based contrast dosing protocol, and 13 patients were scanned using a reduced dose weight-based protocol. Radiodensity was measured at the portal vein, aorta, spleen, and liver. These values were plotted against contrast medium dose per unit weight. Images from all patients were anonymised and presented to two independent consultants who subjectively assessed contrast enhancement using a five-point Likert scale. RESULTS: Using a fixed-dose protocol, there was a statistically significant negative correlation and trend between patient weight and radiodensity at the portal vein, aorta, spleen, and liver. Using a full-dose weight-based contrast dosing protocol, there was no longer a statistically significant correlation or trend implying a more consistent degree of enhancement over a spectrum of patient weights. In addition, when the full-dose weight-based contrast dosing protocol was used, there was a statistically significant increase in the number of scans subjectively assessed as having ideal enhancement and a statistically significant decrease in the number of scans felt to have excessive enhancement when compared to a fixed-dose protocol. The weight-based dosing protocol used less contrast medium than the fixed-dose protocol and there was no evidence of contrast-induced acute kidney injury (CIAKI) in any of the patients that received a greater dose than that which they would have received using a fixed-dose protocol. The reduced-dose weight-based protocol showed less objective enhancement of the portal vein, abdominal aorta, spleen, and liver compared to the full-dose protocol and a reduction in the number of scans perceived as showing ideal enhancement. There was, however, no increase in the number of scans with poor or non-diagnostic enhancement. CONCLUSION: Weight-based contrast medium dosing has been shown to objectively provide more consistent vessel and solid-organ enhancement and subjectively improve image quality across a spectrum of weights. Depending on mean patient mass, it has also been shown to reduce overall contrast medium dose, and there is no evidence of CIAKI in patients that receive larger doses. This study also postulates that a standardised approach to contrast medium dose reduction in patients with renal impairment may be a viable strategy.

Micro-CT scouting for transmission electron microscopy of human tissue specimens.

Transmission electron microscopy (TEM) provides sub-nanometre-scale details in volumetric samples. Samples such as pathology tissue specimens are often stained with a metal element to enhance contrast, which makes them opaque to optical microscopes. As a result, it can be a lengthy procedure to find the region of interest inside a sample through sectioning. We describe micro-CT scouting for TEM that allows noninvasive identification of regions of interest within a block sample to guide the sectioning step. In a tissue pathology study, a bench-top micro-CT scanner with 10 µm resolution was used to determine the location of patches of the mucous membrane in osmium-stained human nasal scraping samples. Once the regions of interest were located, the sample block was sectioned to expose that location, followed by ultra-thin sectioning and TEM to inspect the internal structure of the cilia of the membrane epithelial cells with nanometre resolution. This method substantially reduced the time and labour of the search process from typically 20 sections for light microscopy to three sections with no added sample preparation.

Ileostomy obstruction by ingested apricot stone with clinical-radiological-pathological correlation.

Patients with stomas often present with bowel obstruction, often secondary to adhesions. This case describes the presentation, investigation and management of a 62-year-old woman with an end ileostomy, who presented to hospital with acute abdominal pain and subacute bowel obstruction. Further questioning revealed the recent ingestion of an apricot stone and this was identified by multimodality imaging as the cause of the luminal obstruction in the distal ileum, just proximal to the stoma. After a failed period of conservative management, examination under anaesthesia was performed and digital extraction attempted, but this was unsuccessful. Rather than surgical stoma revision, endoscopic removal was achieved. The patient improved and was discharged the following day. However, her small bowel obstruction relapsed within 48 h. She was readmitted and underwent stoma revision with no further problems.

Effective control of a suspected cyromazine-resistant strain of Lucilia cuprina using commercial spray-on formulations of cyromazine or dicyclanil.

OBJECTIVE: To demonstrate the protection of Merino sheep from flystrike by Lucilia cuprina with cyromazine or dicyclanil in an implant study and in the field. METHODS: In the implant study, sheep were treated with cyromazine or dicyclanil and implanted with 1st-stage larvae from a newly isolated field strain of L. cuprina (CYR-LS) or a reference strain (DZR50), then assessed over 3 days and compared with the implants on untreated control sheep. In the field study, weaner lambs were treated with cyromazine or dicyclanil and monitored weekly for flystrike over 18 weeks of grazing on the same farm from which the L. cuprina were isolated. RESULTS: Implant study: cyromazine (6%) provided effective protection against CYR-LS and DZR50 L. cuprina for a minimum of 13 and 10 weeks, respectively. Dicyclanil (5%) provided at least 18 weeks' protection against both strains. Field study: only 1 of 386 lambs in the cyromazine-treated group was struck in the first 14 weeks of the trial. No strikes occurred in the 198 sheep treated with dicyclanil (5%). Rainfall, temperature and flytrap data indicated consistent fly pressure during the study. CONCLUSIONS: Based on the results of these studies, there was no evidence of reduced susceptibility to cyromazine or dicyclanil and the periods of protection of sheep against L. cuprina were unaffected and consistent with the registered label claims.

Wake-up Strokes Are Similar to Known-Onset Morning Strokes in Severity and Outcome.

BACKGROUND: Stroke symptoms noticed upon waking, wake-up stroke, account for up to a quarter of all acute ischemic strokes. Patients with wake-up stroke, however, are often excluded from thrombolytic therapy. METHODS: Using our prospectively collected stroke registry, wake-up stroke and known-onset morning strokes were identified. Wakeup stroke was defined as a patient who was asleep >3 hours and first noted stroke symptoms upon awakening between 0100 and 1100. Known-onset morning stroke was defined as a patient who had symptom onset while awake during the same time interval. We compared wake-up stoke to known-onset morning stroke with respect to patient demographics, stroke severity, etiology and outcomes. RESULTS: One-quarter of patients with acute ischemic strokes (391/1415) had documented time between 0100 and 1100 of symptom onset: 141 (36%) wake-up strokes and 250 (64%) known-onset morning strokes. No difference in baseline characteristics, stroke severity, stroke etiology, neurologic deterioration, discharge disposition or functional outcome was detected. Known-onset morning stroke patients were significantly more likely to get thrombolytic therapy and have higher risk of in-hospital mortality. Wake-up stroke patients tended to be older, have higher diastolic blood pressure and have longer length of hospital stay. DISCUSSION: While patients with wake-up stroke were similar to patients with known-onset morning stroke in many respects, patients with known onset morning stroke were significantly more likely to get treated with thrombolytic therapy and have higher in-hospital mortality.

Xenon treatment protects against cold ischemia associated delayed graft function and prolongs graft survival in rats.

Prolonged hypothermic storage causes ischemia-reperfusion injury (IRI) in the renal graft, which is considered to contribute to the occurrence of the delayed graft function (DGF) and chronic graft failure. Strategies are required to protect the graft and to prolong renal graft survival. We demonstrated that xenon exposure to human proximal tubular cells (HK-2) led to activation of range of protective proteins. Xenon treatment prior to or after hypothermia-hypoxia challenge stabilized the HK-2 cellular structure, diminished cytoplasmic translocation of high-mobility group box (HMGB) 1 and suppressed NF-κB activation. In the syngeneic Lewis-to-Lewis rat model of kidney transplantation, xenon exposure to donors before graft retrieval or to recipients after engraftment decreased caspase-3 expression, localized HMGB-1 within nuclei and prevented TLR-4/NF-κB activation in tubular cells; serum pro-inflammatory cytokines IL-1ß, IL-6 and TNF-α were reduced and renal function was preserved. Xenon treatment of graft donors or of recipients prolonged renal graft survival following IRI in both Lewis-to-Lewis isografts and Fischer-to-Lewis allografts. Xenon induced cell survival or graft functional recovery was abolished by HIF-1α siRNA. Our data suggest that xenon treatment attenuates DGF and enhances graft survival. This approach could be translated into clinical practice leading to a considerable improvement in long-term graft survival.

The comparative efficacy of abamectin, monepantel and an abamectin/derquantel combination against fourth-stage larvae of a macrocyclic lactone-resistant Teladorsagia spp. isolate infecting sheep.

Anthelmintic resistance by gastrointestinal nematodes of sheep continues to be an issue of global interest. While the recent introduction in some countries of one or two new anthelmintic classes (amino-acetonitrile derivatives [AAD] and spiroindoles [SI]) has been welcomed, it is important that there is no relaxation in parasite control and the management of drug resistance. Monepantel (an AAD) was the first new anthelmintic to be approved for use (New Zealand, 2009) and was followed a year later in the same country by a combination of derquantel (a SI) and abamectin. The present study determined the efficacy of the new anthelmintic products and abamectin against fourth-stage larvae of macrocyclic lactone-resistant Teladorsagia spp. in lambs. Efficacies were calculated by comparing post-mortem nematode burdens of treated animals with those of untreated control sheep, and were 98.5, 86.3 and 34.0% for monepantel, abamectin/derquantel and abamectin, respectively. The nematode burdens of monepantel- and abamectin/derquantel-treated sheep were significantly lower than those sheep treated with abamectin and the untreated controls. Similarly, the burden of the monepantel group was significantly lower than that of the abamectin/derquantel group. These findings provide an opportunity to reinforce the recommendation that farmers and animal health advisors need to know the resistance status of nematode populations on subject farms to ensure effective control programs are designed and implemented. Such control programs should include an appropriate choice of anthelmintic(s), monitoring parasite burdens for correct timing of treatments, and pasture management to reduce larval challenge balanced with the maintenance of drug-susceptible populations in refugia.

AKT induces senescence in human cells via mTORC1 and p53 in the absence of DNA damage: implications for targeting mTOR during malignancy.

The phosphatidylinositol 3-kinase (PI3K)/AKT and RAS oncogenic signalling modules are frequently mutated in sporadic human cancer. Although each of these pathways has been shown to play critical roles in driving tumour growth and proliferation, their activation in normal human cells can also promote cell senescence. Although the mechanisms mediating RAS-induced senescence have been well characterised, those controlling PI3K/AKT-induced senescence are poorly understood. Here we show that PI3K/AKT pathway activation in response to phosphatase and tensin homolog (PTEN) knockdown, mutant PI3K, catalytic, α polypeptide (PIK3CA) or activated AKT expression, promotes accumulation of p53 and p21, increases cell size and induces senescence-associated ß-galactosidase activity. We demonstrate that AKT-induced senescence is p53-dependent and is characterised by mTORC1-dependent regulation of p53 translation and stabilisation of p53 protein following nucleolar localisation and inactivation of MDM2. The underlying mechanisms of RAS and AKT-induced senescence appear to be distinct, demonstrating that different mediators of senescence may be deregulated during transformation by specific oncogenes. Unlike RAS, AKT promotes rapid proliferative arrest in the absence of a hyperproliferative phase or DNA damage, indicating that inactivation of the senescence response is critical at the early stages of PI3K/AKT-driven tumourigenesis. Furthermore, our data imply that chronic activation of AKT signalling provides selective pressure for the loss of p53 function, consistent with observations that PTEN or PIK3CA mutations are significantly associated with p53 mutation in a number of human tumour types. Importantly, the demonstration that mTORC1 is an essential mediator of AKT-induced senescence raises the possibility that targeting mTORC1 in tumours with activated PI3K/AKT signalling may exert unexpected detrimental effects due to inactivation of a senescence brake on potential cancer-initiating cells.

Upregulation of chemokine expression in murine cornea due to mechanical trauma or endotoxin.

BACKGROUND AND AIMS: Allograft rejection is the commonest cause of corneal transplant failure and is significantly higher in high-risk patients. Corneal tissue is reported to produce chemokines in response to stress/inflammation. Expression of chemokines is central to the recruitment of leucocytes during inflammatory events. This study was designed to evaluate the effects of surgical trauma or storage conditions on chemokine expression. METHODS: Murine corneas were manipulated by incubation in different conditions for up to 24 h, by the addition of endotoxin or by surgical trauma. The ex vivo production of chemokines was assessed using a real-time reverse-transcriptase PCR (RT-PCR) assay to measure mRNA encoding MIP-1alpha, MIP-1beta and MIP-1gamma, MCP1, IP-10, lymphotactin, fractalkine, RANTES, eotaxin, MIG, MIP2 and the cytokine MIF. The expression of RANTES was also determined by ELISA, and the ability of supernatant from corneas on chemotaxis of cells was also determined. Finally, we compared the survival of corneal grafts that had (or had not) been treated with endotoxin. RESULTS: We found that on incubation in corneal storage medium, expression of mRNA for the majority of these chemokines greatly increased. Upregulation of chemokine mRNA expression was also seen following the mechanical trauma of suture insertion and exposure of the cornea to endotoxin. In the case of mechanical trauma, functional activity of the chemokines was demonstrated using a chemotaxis assay. Orthotopic transplantation of LPS-treated corneas, in which chemokine expression was elevated, resulted in increased infiltration by leucocytes and more rapid rejection of allogeneic grafts. CONCLUSION: Our results indicate that ex vivo storage and manipulation of murine corneas can influence the expression of chemokines in corneas, and can result in earlier graft rejection. This may be of importance when considering procedures for manipulation and ex vivo storage of donor corneas prior to transplantation, as well as the surgical procedure itself.

Smooth muscle cell proliferation but not neointimal formation is dependent on alloantibody in a murine model of intimal hyperplasia.

Transplant coronary artery disease is the pre-eminent cause of late cardiac allograft failure. It is primarily characterized by a concentric intimal hyperplasia, which we designate transplant intimal hyperplasia (TIH). Although the pathogenesis of TIH is predominately immune driven, the specific role of alloantibodies in the disease process remains undefined. In this study we investigated the contribution of alloantibodies to the development of TIH in a murine model. Orthotopic, carotid artery transplantation was performed between B10A(2R) (H-2(h2)) donor mice and B-cell deficient muMT(-/-) knockout or wild-type C57BL/6 (H-2(b)) recipients in the absence of immunosuppression. Grafts were harvested at 35 days and subjected to planimetry and immunohistochemistry. Alloantibodies were detectable in wild-type recipients within 7 days of transplantation and recipients developed marked TIH at 35 days. Allografts harvested from B-cell deficient recipient mice also developed TIH, which was comparable in severity with wild-type recipients. However, whereas allografts from wild-type recipients showed marked intimal smooth muscle cell (SMC) proliferation, the neointima in B-cell deficient recipients lacked SMCs. Post-transplantation administration of anti-donor serum to muMT(-/-) recipients restored neointimal SMC population but did not influence the severity of TIH. Significant neointimal formation occurs in the absence of alloantibodies but lacks a SMC component. Therefore, SMC migration and proliferation is antibody dependent.

A rapid method for labelling CD4+ T cells with ultrasmall paramagnetic iron oxide nanoparticles for magnetic resonance imaging that preserves proliferative, regulatory and migratory behaviour in vitro.

A number of techniques have been developed to track the migration of T cells in vivo, but they all suffer significant shortcomings, including the examination of selected organs rather than the organism as a whole--thus precluding longitudinal studies--or limitations imposed by poor spatial resolution and the application of ionizing radiation. By conjugating the HIV tat peptide to ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles in a reaction yielding a mean valence of 45, a magnetic resonance (MR) contrast agent was synthesised that allowed T cells to be efficiently labelled within just 5 min. The USPIO nanoparticles were incorporated into both the cytoplasm and nucleus of labelled cells, which retained normal in vitro proliferative responses to a polyclonal stimulus; suppressive responses mediated by labelled CD4(+) CD25(+) regulatory T cells; chemotactic responses to the chemokine CXCL-12; and transmigration of an activated endothelial monolayer. We believe that this rapid, efficient and essentially non-toxic approach to labelling both murine and human T cells for MRI holds considerable promise, paving the way for the wider immunological application of this exciting technology.

Aspirin-treated human DCs up-regulate ILT-3 and induce hyporesponsiveness and regulatory activity in responder T cells.

Mature dendritic cells (mDCs) are potent antigen presenting cells, but immature DCs (iDCs) have been shown to have reduced antigen stimulatory capacity. Different strategies have been investigated to augment the tolerogenic capacity of dendritic cells (DCs). We demonstrate that in aspirin-treated human DCs, there is reduced expression of CD1a, HLA-DR and CD86, up-regulation of ILT-3 expression and marginal increases in PDL-1. Aspirin-treated DCs are partially resistant to phenotypic changes following maturational stimuli, such as lipopolysaccharide (LPS) or TNFalpha, IL-1alpha and PGE2. Aspirin-treated DCs demonstrate normal endocytic function, but have a reduced ability to stimulate allogeneic T cells, which is comparable to iDCs. Furthermore, they induce hyporesponsiveness and regulatory activity in responder naïve and memory T cells; for naïve T cells this is achieved more quickly and efficiently than with iDCs. We investigated the mechanism of this regulatory activity and found that both cell-cell contact and inhibitory cytokine activity are involved, although no one cytokine predominates in importance. Blocking ILT-3 or IL-12 does not diminish the capacity of these DCs to induce regulation or Foxp3 expression on the regulatory T cells. Results demonstrate that aspirin-treated DCs display tolerogenic potential, which is of interest in their therapeutic potential in reducing chronic allograft rejection.