Recently portable Raman probes have emerged along with a variety of applications, including carbon nanotube (CNT) characterization. Aqueous dispersed CNTs have shown promise for biomedical ...applications such as drug/gene delivery vectors, photo-thermal therapy, and photoacoustic imaging. In this study we report the simultaneous detection and irradiation of carbon nanotubes in 2D monolayers of cancer cells and in 3D spheroids using a portable Raman probe. A portable handheld Raman instrument was utilized for dual purposes: as a CNT detector and as an irradiating laser source. Single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) were dispersed aqueously using a lipid-polymer (LP) coating, which formed highly stable dispersions both in buffer and cell media. The LP coated SWCNT and MWCNT aqueous dispersions were characterized by atomic force microscopy, transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy and Raman spectroscopy. The cellular uptake of the LP-dispersed SWCNTs and MWCNTs was observed using confocal microscopy, and fluorescein isothiocyanate (FITC)-nanotube conjugates were found to be internalized by ovarian cancer cells by using Z-stack fluorescence confocal imaging. Biocompatibility of SWCNTs and MWCNTs was assessed using a cell viability MTT assay, which showed that the nanotube dispersions did not hinder the proliferation of ovarian cancer cells at the dosage tested. Ovarian cancer cells treated with SWCNTs and MWCNTs were simultaneously detected and irradiated live in 2D layers of cancer cells and in 3D environments using the portable Raman probe. An apoptotic terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay carried out after laser irradiation confirmed that cell death occurred only in the presence of nanotube dispersions. We show for the first time that both SWCNTs and MWCNTs can be selectively irradiated and detected in cancer cells using a simple handheld Raman instrument. This approach could potentially be used to treat various diseases, including cancer.
We report the investigation of the self-assembly mechanism of nanofibers, using a small peptide amphiphile (NapFFKYp) as a model. Combining experimental and simulation methods, we identify the ...self-assembly pathways in the solution and on the substrates, respectively. In the solution, peptide amphiphiles undergo the nucleation process to grow into nanofibers. The nanofibers can further twist into high-ordered nanofibers with aging. On the substrates, peptide amphiphiles form nanofibers and nanosheet structures simultaneously. This surface-induced nanosheet consists of rod-like structures, and its thickness is substrate-dependent. Most intriguingly, water can transform the nanosheet into the nanofiber. Molecular dynamic simulation suggests that hydrophobic and ion-ion interactions are dominant forces during the self-assembly process.
Immunization with a recombinant yeast-expressed
Plasmodium falciparum merozoite surface protein 3 (MSP3) protected
Aotus nancymai monkeys against a virulent challenge infection. Unfortunately, the ...production process for this yeast-expressed material was not optimal for human trials. In an effort to produce a recombinant MSP3 protein in a scaleable manner, we expressed and purified near-full-length MSP3 in
Escherichia coli (EcMSP3). Purified EcMSP3 formed non-globular dimers as determined by analytical size-exclusion HPLC with in-line multi-angle light scatter and quasi-elastic light scatter detection and velocity sedimentation (
R
h
7.6
±
0.2
nm and 6.9
nm, respectively). Evaluation by high-resolution atomic force microscopy revealed non-linear asymmetric structures, with beaded domains and flexible loops that were recognized predominantly as dimers, although monomers and larger multimers were observed. The beaded substructure corresponds to predicted structural domains, which explains the velocity sedimentation results and improves the conceptual model of the protein. Vaccination with EcMSP3 in Freund's adjuvant-induced antibodies that recognized native MSP3 in parasitized erythrocytes by an immunofluorescence assay and gave delayed time to treatment in a group of
Aotus monkeys in a virulent challenge infection with the FVO strain of
P. falciparum. Three of the seven monkeys vaccinated with EcMSP3 had low peak parasitemias. EcMSP3, which likely mimics the native MSP3 structure located on the merozoite surface, is a viable candidate for inclusion in a multi-component malaria vaccine.
Atrial fibrillation is a leading preventable cause of recurrent stroke for which early detection and treatment are critical. However, paroxysmal atrial fibrillation is often asymptomatic and likely ...to go undetected and untreated in the routine care of patients with ischemic stroke or transient ischemic attack (TIA).
We randomly assigned 572 patients 55 years of age or older, without known atrial fibrillation, who had had a cryptogenic ischemic stroke or TIA within the previous 6 months (cause undetermined after standard tests, including 24-hour electrocardiography ECG), to undergo additional noninvasive ambulatory ECG monitoring with either a 30-day event-triggered recorder (intervention group) or a conventional 24-hour monitor (control group). The primary outcome was newly detected atrial fibrillation lasting 30 seconds or longer within 90 days after randomization. Secondary outcomes included episodes of atrial fibrillation lasting 2.5 minutes or longer and anticoagulation status at 90 days.
Atrial fibrillation lasting 30 seconds or longer was detected in 45 of 280 patients (16.1%) in the intervention group, as compared with 9 of 277 (3.2%) in the control group (absolute difference, 12.9 percentage points; 95% confidence interval CI, 8.0 to 17.6; P<0.001; number needed to screen, 8). Atrial fibrillation lasting 2.5 minutes or longer was present in 28 of 284 patients (9.9%) in the intervention group, as compared with 7 of 277 (2.5%) in the control group (absolute difference, 7.4 percentage points; 95% CI, 3.4 to 11.3; P<0.001). By 90 days, oral anticoagulant therapy had been prescribed for more patients in the intervention group than in the control group (52 of 280 patients 18.6% vs. 31 of 279 11.1%; absolute difference, 7.5 percentage points; 95% CI, 1.6 to 13.3; P=0.01).
Among patients with a recent cryptogenic stroke or TIA who were 55 years of age or older, paroxysmal atrial fibrillation was common. Noninvasive ambulatory ECG monitoring for a target of 30 days significantly improved the detection of atrial fibrillation by a factor of more than five and nearly doubled the rate of anticoagulant treatment, as compared with the standard practice of short-duration ECG monitoring. (Funded by the Canadian Stroke Network and others; EMBRACE ClinicalTrials.gov number, NCT00846924.).
It is still in high demand to develop extremely sensitive and accurate clinical tools for biomarkers of interest for early diagnosis and monitoring of diseases. In this report, we present a highly ...sensitive and compatible gold nanoparticle (AuNP)-based fluorescence activatable probe for sensing ultra-low levels of prostate-specific antigen (PSA) in patient serum samples. The limit of detection of the newly-developed probe for PSA was pushed down to 0.032 pg/mL, which is more than two orders of magnitude lower than that of the conventional fluorescence probe. The ultrahigh sensitivity of this probe was attributed to the high loading efficiency of the dyes on AuNP surfaces and high fluorescence quenching unquenching abilities of the dye-AuNP pairs. The efficiency and robustness of this probe was investigated in patient serum samples, demonstrating the great potential of this probe in real-world applications.
Recanalization of intracranial thrombus is associated with improved clinical outcome in patients with acute ischemic stroke. The association of intravenous alteplase treatment and thrombus ...characteristics with recanalization over time is important for stroke triage and future trial design.
To examine recanalization over time across a range of intracranial thrombus occlusion sites and clinical and imaging characteristics in patients with ischemic stroke treated with intravenous alteplase or not treated with alteplase.
Multicenter prospective cohort study of 575 patients from 12 centers (in Canada, Spain, South Korea, the Czech Republic, and Turkey) with acute ischemic stroke and intracranial arterial occlusion demonstrated on computed tomographic angiography (CTA).
Demographics, clinical characteristics, time from alteplase to recanalization, and intracranial thrombus characteristics (location and permeability) defined on CTA.
Recanalization on repeat CTA or on first angiographic acquisition of affected intracranial circulation obtained within 6 hours of baseline CTA, defined using the revised arterial occlusion scale (rAOL) (scores from 0 primary occlusive lesion remains the same to 3 complete revascularization of primary occlusion).
Among 575 patients (median age, 72 years IQR, 63-80; 51.5% men; median time from patient last known well to baseline CTA of 114 minutes IQR, 74-180), 275 patients (47.8%) received intravenous alteplase only, 195 (33.9%) received intravenous alteplase plus endovascular thrombectomy, 48 (8.3%) received endovascular thrombectomy alone, and 57 (9.9%) received conservative treatment. Median time from baseline CTA to recanalization assessment was 158 minutes (IQR, 79-268); median time from intravenous alteplase start to recanalization assessment was 132.5 minutes (IQR, 62-238). Successful recanalization occurred at an unadjusted rate of 27.3% (157/575) overall, including in 30.4% (143/470) of patients who received intravenous alteplase and 13.3% (14/105) who did not (difference, 17.1% 95% CI, 10.2%-25.8%). Among patients receiving alteplase, the following factors were associated with recanalization: time from treatment start to recanalization assessment (OR, 1.28 for every 30-minute increase in time 95% CI, 1.18-1.38), more distal thrombus location, eg, distal M1 middle cerebral artery (39/84 46.4%) vs internal carotid artery (10/92 10.9%) (OR, 5.61 95% CI, 2.38-13.26), and higher residual flow (thrombus permeability) grade, eg, hairline streak (30/45 66.7%) vs none (91/377 24.1%) (OR, 7.03 95% CI, 3.32-14.87).
In patients with acute ischemic stroke, more distal thrombus location, greater thrombus permeability, and longer time to recanalization assessment were associated with recanalization of arterial occlusion after administration of intravenous alteplase; among patients who did not receive alteplase, rates of arterial recanalization were low. These findings may help inform treatment and triage decisions in patients with acute ischemic stroke.
Conventional evaluation methods of chemotherapeutic efficacy such as tissue biopsy and anatomical measurement are either invasive with potential complications or dilatory to capture the rapid ...pathological changes. Here, a sensitive and resolution-scalable photoacoustic microscopy (PAM) with theranostic nanoformulation was developed to noninvasively monitor the therapy response in a timely manner. Ultrasmall graphene oxide nanosheets were designed as both drug-loading vehicle and photoacoustic signal amplifier to the tumor. With the signal enhancement by the injected contrast agents, the subtle microvascular changes of the chemotherapy response in tumor were advantagely revealed by our PAM system, which was much earlier than the morphological measurement by standard imaging techniques. High tumor uptake of the enhanced nanodrug with Cy5.5 labeling was validated by fluorescence imaging. At different observation scales, PAM offered unprecedented sensitivity of optical absorption and high spatial resolution over optical imaging. Our studies demonstrate the PAM system with synergistic theranostic strategy to be a multiplexing platform for tumor diagnosis, drug delivery, and chemotherapy response monitoring at a very early stage and in an effective way.
Background: Isolated dysarthria is an uncommon presentation of transient ischemic attack (TIA)/minor stroke and has a broad differential diagnosis. There is little information in the literature about ...how often this presentation is confirmed to be a TIA/stroke, and therefore there is debate about the risk of subsequent vascular events. Given the uncertain prognosis, it is unclear how to best manage patients presenting to the emergency department (ED) with isolated dysarthria. The objective of this study was to prospectively identify and follow a cohort of patients presenting to EDs with isolated dysarthria in order to explore their natural history and risk of recurrent cerebrovascular events. Specifically, we sought to determine early outcomes of individuals with this nonspecific and atypical presentation in order to appropriately expedite their management. Methods: Patients with isolated dysarthria having presented to 8 Canadian EDs between October 2006 and April 2009 were analyzed as part of a prospective multicenter cohort study of patients with acute neurological symptoms as assessed by emergency physicians. The study inclusion criteria were age ≥18 years, a normal level of consciousness, and a symptom onset <1 week prior to presentation without an established nonvascular etiology. The primary outcome was a subsequent stroke within 90 days of the index visit. The secondary outcomes were the rate of TIA, myocardial infarction, and death. Isolated dysarthria was defined as slurring with imprecise articulation but without evidence of language dysfunction. The overall rate of stroke in this cohort was compared with that predicted by the median ABCD2 score for this group. Results: Between 2006 and 2009, 1,528 patients were enrolled and had a 90-day follow-up. Of these, 43 patients presented with isolated acute-onset dysarthria (2.8%). Recurrent stroke occurred in 6/43 (14.0%) within 90 days of enrollment. The predicted maximal 90-day stroke rate was 9.8% (based on a median ABCD2 score of 5 for the isolated dysarthria cohort). After adjusting for covariates, isolated dysarthria independently predicted stroke within 90 days (aOR: 3.96; 95% CI: 1.3-11.9; p = 0.014). Conclusions: The isolated dysarthria cohort carried a recurrent stroke risk comparable to that predicted by the median ABCD2 scores. Although isolated dysarthria is a nonspecific and uncommon clinical presentation of TIA, these findings support the need to view it first and foremost as a vascular presentation until proven otherwise and to manage such patients as if they were at high risk of stroke in accordance with established high-risk TIA guidelines.
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