48 research outputs found
Rapid Stereomicroscopic Imaging of HER2 Overexpression in Ex Vivo Breast Tissue Using Topically Applied Silica-Based Gold Nanoshells
Tumor margin detection for patients undergoing breast conservation surgery primarily occurs postoperatively. Previously, we
demonstrated that gold nanoshells rapidly enhance contrast of HER2 overexpression in ex vivo tissue sections. Our ultimate
objective, however, is to discern HER2 overexpressing tissue from normal tissue in whole, nonsectioned, specimens to facilitate
rapid diagnoses. Here, we use targeted nanoshells to quickly and effectively visualize HER2 receptor expression in intact ex vivo
human breast tissue specimens. Punch biopsies of human breast tissue were analyzed after a brief 5-minute incubation with and
without HER2-targeted silica-gold nanoshells using two-photon microscopy and stereomicroscopy. Labeling was subsequently
verified using reflectance confocal microscopy, darkfield hyperspectral imaging, and immunohistochemistry to confirm levels
of HER2 expression. Our results suggest that anti-HER2 nanoshells used in tandem with a near-infrared reflectance confocal
microscope and a standard stereomicroscope may potentially be used to discern HER2-overexpressing cancerous tissue from
normal tissue in near real time and offer a rapid supplement to current diagnostic techniques
T cells enhance gold nanoparticle delivery to tumors in vivo
Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production). Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation
Size-controlled synthesis of monodispersed gold nanoparticles via carbon monoxide gas reduction
An in depth analysis of gold nanoparticle (AuNP) synthesis and size tuning, utilizing carbon monoxide (CO) gas as a reducing agent, is presented for the first time. The sizes of the AuNPs are tunable from ~4 to 100 nm by altering the concentration of HAuCl4 and inlet CO gas-injection flow rate. It is also found that speciation of aqueous HAuCl4, prior to reduction, influences the size, morphology, and properties of AuNPs when reduced with CO gas. Ensemble extinction spectra and TEM images provide clear evidence that CO reduction offers a high level of monodispersity with standard deviations as low as 3%. Upon synthesis, no excess reducing agent remains in solution eliminating the need for purification. The time necessary to synthesize AuNPs, using CO, is less than 2 min
Elimination of Metastatic Melanoma Using Gold Nanoshell-Enabled Photothermal Therapy and Adoptive T Cell Transfer
Ablative treatments such as photothermal therapy (PTT) are attractive anticancer strategies because they debulk accessible
tumor sites while simultaneously priming antitumor immune responses. However, the immune response following thermal
ablation is often insufficient to treat metastatic disease. Here we demonstrate that PTT induces the expression of
proinflammatory cytokines and chemokines and promotes the maturation of dendritic cells within tumor-draining lymph
nodes, thereby priming antitumor T cell responses. Unexpectedly, however, these immunomodulatory effects were not
beneficial to overall antitumor immunity. We found that PTT promoted the infiltration of secondary tumor sites by
CD11b+Ly-6G/C+ myeloid-derived suppressor cells, consequently failing to slow the growth of poorly immunogenic B16-F10
tumors and enhancing the growth of distant lung metastases. To exploit the beneficial effects of PTT activity against local
tumors and on antitumor immunity whilst avoiding the adverse consequences, we adoptively transferred gp100-specific
pmel T cells following PTT. The combination of local control by PTT and systemic antitumor immune reactivity provided by
adoptively transferred T cells prevented primary tumor recurrence post-ablation, inhibited tumor growth at distant sites,
and abrogated the outgrowth of lung metastases. Hence, the combination of PTT and systemic immunotherapy prevented
the adverse effects of PTT on metastatic tumor growth and optimized overall tumor control
The Photoeccentric Effect and Proto-Hot Jupiters II. KOI-1474.01, a candidate eccentric planet perturbed by an unseen companion
The exoplanets known as hot Jupiters---Jupiter-sized planets with periods
less than 10 days---likely are relics of dynamical processes that shape all
planetary system architectures. Socrates et al. (2012) argued that high
eccentricity migration (HEM) mechanisms proposed for situating these close-in
planets should produce an observable population of highly eccentric proto-hot
Jupiters that have not yet tidally circularized. HEM should also create
failed-hot Jupiters, with periapses just beyond the influence of fast
circularization. Using the technique we previously presented for measuring
eccentricities from photometry (the "photoeccentric effect"), we are distilling
a collection of eccentric proto- and failed-hot Jupiters from the Kepler
Objects of Interest (KOI). Here we present the first, KOI-1474.01, which has a
long orbital period (69.7340 days) and a large eccentricity e =
0.81+0.10/-0.07, skirting the proto-hot Jupiter boundary. Combining Kepler
photometry, ground-based spectroscopy, and stellar evolution models, we
characterize host KOI-1474 as a rapidly-rotating F-star. Statistical arguments
reveal that the transiting candidate has a low false-positive probability of
3.1%. KOI-1474.01 also exhibits transit timing variations of order an hour. We
explore characteristics of the third-body perturber, which is possibly the
"smoking-gun" cause of KOI-1474.01's large eccentricity. Using the host-star's
rotation period, radius, and projected rotational velocity, we find
KOI-1474.01's orbit is marginally consistent with aligned with the stellar spin
axis, although a reanalysis is warranted with future additional data. Finally,
we discuss how the number and existence of proto-hot Jupiters will not only
demonstrate that hot Jupiters migrate via HEM, but also shed light on the
typical timescale for the mechanism.Comment: ApJ, in press. Received 2012 July 7; accepted 2012 October 1
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.
Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707