Aptamers: Features, Synthesis and Applications

Aptamers have become a topic of interest among the researchers and scientists since they not only possess all of the benefits of antibodies but also possess special qualities including heat stability, low cost, and limitless uses⋅ Here we give a review about the features, applications, and challenges of aptamers and also how they are beneficial over the antibodies for biomedical applications. Their unique features make aptamers a prominent tool in therapeutics, diagnostics, biosensors and targeted drug delivery. In conclusion, aptamers represent exciting materials for a variety of applications and can be modified to improve their properties and to extend their applications in biomedical field.

Betatron radiation and emittance growth in plasma wakefield accelerators

Beam-driven plasma wakefield acceleration (PWFA) has demonstrated significant progress during the past two decades of research. The new Facility for Advanced Accelerator Experimental Tests (FACET) II, currently under construction, will provide 10 GeV electron beams with unprecedented parameters for the next generation of PWFA experiments. In the context of the FACET II facility, we present simulation results on expected betatron radiation and its potential application to diagnose emittance preservation and hosing instability in the upcoming PWFA experiments. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Producing multi-coloured bunches through beam-induced ionization injection in plasma wakefield accelerator

This paper discusses the properties of electron beams formed in plasma wakefield accelerators through ionization injection. In particular, the potential for generating a beam composed of co-located multi-colour beamlets is demonstrated in the case where the ionization is initiated by the evolving charge field of the drive beam itself. The physics of the processes of ionization and injection are explored through OSIRIS simulations. Experimental evidence showing similar features are presented from the data obtained in the E217 experiment at the FACET facility of the SLAC National Laboratory. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Abstract P2-06-02: Development of a first-in-class small molecule inhibitor (EC359) targeting oncogenic LIF/LIFR signaling for the treatment of triple negative breast cancer

Background: Leukemia inhibitory factor (LIF) and its receptor LIFR are over-expressed in multiple solid tumors and play a key role in tumor growth, progression, and resistance to standard anti-cancer treatments. Triple-negative breast cancer (TNBC) lacks targeted therapies and represents a disproportional share of breast cancer (BCa) mortality. TNBC exhibits autocrine stimulation of the LIF/LIFR axis and overexpression of LIF is associated with poorer relapse-free survival in BCa patients. LIF signaling also promotes maintenance of stem cells. Therefore, targeting the LIF/LIFR axis may have therapeutic utility in TNBC.

Methods: We rationally designed a small organic molecule (EC359) that emulates the LIF/LIFR binding site and functions as a LIFR inhibitor from a library of compounds. In silico docking studies were used to identify the putative interaction of the EC359 and LIF/LIFR complex. Direct binding of EC359 to LIFR was confirmed using surface plasmon resonance (SPR) and microscale thermophoresis technique (MST) assays. In vitro activity was tested using Cell-Titer Glo, MTT, invasion, and apoptosis assays. Mechanistic studies were conducted using Western blot, reporter gene assays, and RNA-seq analysis. Xenograft, patient-derived xenograft (PDX), and patient-derived explant (PDEX) models were used for preclinical evaluation and toxicity.

Results: Molecular docking studies showed that EC359 interacts at the LIF/LIFR binding interface. SPR and MST studies confirmed direct interaction of EC359 to LIFR. EC359 reduced the growth of TNBC cells with high potency (IC50 50-100nM) and promoted apoptosis. Further, EC359 treatment reduced invasion and stemness of TNBC cells. EC359 activity is dependent on the expression levels of LIFR and showed little or no activity on TNBC cells that have low levels of LIFR or ER+ve BCa cells. Further, EC359 significantly reduced the viability of cisplatin and taxane-resistant TNBC cells and enhanced the efficacy of HDAC inhibitors. Mechanistic and biochemical studies showed that EC359 interacts with LIFR and effectively blocking LIF/LIFR interactions. EC359 also blocked LIFR interactions with other LIFR ligands such as oncostatin M, ciliary neurotrophic factor, and cardiotrophin-1. EC359 treatment attenuated the activation of LIF/LIFR driven pathways including STAT3, mTOR, AKT, and MAPK. RNA-seq analysis identified regulation of apoptosis as one of the important pathway modulated by EC359. In TNBC xenograft and PDX assays, EC359 significantly reduced tumor progression. Further, using human primary BCa PDEX cultures, we demonstrated that EC359 has the potential to substantially reduce the proliferation of human BCa. Pharmacologically, EC359 exhibited high oral bioavailability and long half-life with a wide therapeutic window.

Conclusions: EC359 is a novel targeted therapeutic agent that inhibits LIF/LIFR oncogenic signaling in TNBC via a unique mechanism of action. EC359 has the distinct pharmacologic advantages of oral bioavailability, in vivo stability, and is associated with minimal systemic side effects. (DOD BCRP grant #BC170312)

Citation Format: Viswanadhapalli S, Luo Y, Sareddy GR, Santhamma B, Zhou M, Li M, Pratap UP, Altwegg KA, Li X, Srinivasan U, Ma S, Chang A, Riveros AC, Zhang KY, Dileep KV, Pan X, Murali R, Bajda M, Raj G, Brenner A, Manthati V, Rao M, Tekmal RR, Nair HB, Nickisch KJ, Vadlamudi RK. Development of a first-in-class small molecule inhibitor (EC359) targeting oncogenic LIF/LIFR signaling for the treatment of triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-06-02.

An ultra-high gain and efficient amplifier based on Raman amplification in plasma

Raman amplification arising from the excitation of a density echelon in plasma could lead to amplifiers that significantly exceed current power limits of conventional laser media. Here we show that 1-100 J pump pulses can amplify picojoule seed pulses to nearly joule level. The extremely high gain also leads to significant amplification of backscattered radiation from "noise", arising from stochastic plasma fluctuations that competes with externally injected seed pulses, which are amplified to similar levels at the highest pump energies. The pump energy is scattered into the seed at an oblique angle with 14 J sr-1, and net gains of more than eight orders of magnitude. The maximum gain coefficient, of 180 cm-1, exceeds high-power solid-state amplifying media by orders of magnitude. The observation of a minimum of 640 J sr-1 directly backscattered from noise, corresponding to ≈10% of the pump energy in the observation solid angle, implies potential overall efficiencies greater than 10%.

Impact of Laser Beam Speckle Structure on Crossed Beam Energy Transfer via Beam Deflections and Ponderomotive Self-Focusing

The role of laser speckle structure (hot spots) and its ponderomotive self-focusing (PSF), in crossed beam energy transfer (CBET), of smoothed laser beams is investigated in an inhomogeneous expanding plasma. Numerical simulations using the code harmony in two spatial dimensions, demonstrate how self-focusing of laser hot spots in crossed beams can significantly affect the transfer of energy from one beam to the other in addition to the stimulated Brillouin scattering (SBS) process. It is shown that for sufficiently intense laser beams, when the laser hot spots exceed the criterion for self-focusing in a plasma with flow, the angular spread of transmitted light beams increases considerably with the intensity, which arises in particular, in expanding plasma where significant beam deflection is observed. It is shown for the first time that besides SBS, the contribution of speckle structure, PSF, and deflections of the intense hot spots in multiple speckle beams to CBET, therefore matters.

Characterization of glioma-cells derived from human polyomavirus-induced brain-tumors in hamsters

Intracerebral injection of human polyomavirus, JCV, into neonatal hamsters causes tumors of,glial origin. HJC is an established cell Line derived from a JCV-induced mixed hamster brain tumor with astrocytic and ependymal components. Flow cytometric and immunohistochemical analysis of HJC suggests that it is comprised of a mixed population of cells all of which contain the JCV early protein, T-antigen, in the nuclei. Five individual clonal lines, called HJC-15a to HJC-15e, were isolated by limiting dilution and were found to exhibit distinct morphological characteristics with 25-30% variation in their sizes. It was evident that each clone has unique growth rates, doubling times, and cell cycle parameters with different G(1), S, and G(2) phase times. All clonal cells showed the presence of the JCV early protein in the nucleus. Of interest was the observation from immunoprecipitation and Western analysis indicating qualitative and quantitative differences in the T-antigen isoforms produced in these cells. Similar to the parental clone, HJC-15b produced two distinct forms of JCV T-antigen isoforms, 88 kDa and 92 kDa proteins. In addition, HJC-15c was able to produce a 23-25 kDa protein which was recognized by anti-T-antigen antibody. The activity of cyclin-dependent kinases, in particular cdc2, was higher in HJC-15c than in the other cell lines. The data presented herein indicates that glioblastomas induced by viral T-antigen expression are composed of a multitude of distinct cells that possess a variety of different characteristics.

Low emittance, high brilliance relativistic electron beams from a laser-plasma accelerator

Progress in laser wakefield accelerators indicates their suitability as a driver of compact free-electron lasers (FELs). High brightness is defined by the normalized transverse emittance, which should be less than 1π mm mrad for an x-ray FEL. We report high-resolution measurements of the emittance of 125 MeV, monoenergetic beams from a wakefield accelerator. An emittance as low as 1.1±0.1π mm mrad is measured using a pepper-pot mask. This sets an upper limit on the emittance, which is comparable with conventional linear accelerators. A peak transverse brightness of 5×10¹⁵ A m⁻¹ rad⁻¹ makes it suitable for compact XUV FELs.

Adverse cardiac events after surgery: assessing risk in a veteran population

OBJECTIVE

To establish rates of and risk factors for cardiac complications after noncardiac surgery in veterans.

DESIGN

Prospective cohort study.

SETTING

A large urban veterans affairs hospital.

PARTICIPANTS

One thousand patients with known or suspected cardiac problems undergoing 1,121 noncardiac procedures.

MEASUREMENTS

Patients were assessed preoperatively for important clinical variables. Postoperative evaluation was done by an assessor blinded to preoperative status with a daily physical examination, electrocardiogram, and creatine kinase with MB fraction until postoperative day 6, day of discharge, death, or reoperation (whichever occurred earliest). Serial electrocardiograms, enzymes, and chest radiographs were obtained as indicated. Severe cardiac complications included cardiac death, cardiac arrest, myocardial infarction, ventricular tachycardia, and fibrillation and pulmonary edema. Serious cardiac complications included the above, heart failure, and unstable angina.

MAIN RESULTS

Severe and serious complications were seen in 24% and 32% of aortic, 8.3% and 10% of carotid, 11.8% and 14.7% of peripheral vascular, 9.0% and 13.1% of intraabdominal/intrathoracic, 2.9% and 3.3% of intermediate-risk (head and neck and major orthopedic procedures), and 0.27% and 1.1% of low-risk procedures respectively. The five associated patient-specific risk factors identified by logistic regression are: myocardial infarction < 6 months (odds ratio [OR], 4.5; 95% confidence interval [CI], 1.9 to 12.9), emergency surgery (OR, 2.6; 95% CI, 1.2 to 5.6), myocardial infarction > 6 months (OR, 2.2; 95% CI, 1.4 to 3.5), heart failure ever (OR, 1.9; 95% CI, 1.2 to 3.0), and rhythm other than sinus (OR, 1.7; 95% CI, 0.9 to 3.2). Inclusion of the planned operative procedure significantly improves the predictive ability of our risk model.

CONCLUSIONS

Five patient-specific risk factors are associated with high risk for cardiac complications in the perioperative period of noncardiac surgery in veterans. Inclusion of the operative procedure significantly improves the predictive ability of the risk model. Overall cardiac complication rates (pretest probabilities) are established for these patients. A simple nomogram is presented for calculation of post-test probabilities by incorporating the operative procedure.

Influence of body weight on response to subcutaneous vitamin K administration in over-anticoagulated patients

PURPOSE

To determine the influence of body weight on the international normalized ratio (INR) response to a fixed dose of vitamin K in overanticoagulated patients.

METHODS

Retrospective review of records of patients who received 1 mg of vitamin K subcutaneously to correct excessive INR. Dose of vitamin K in milligrams per kilograms plotted against change in INR in 24 hours.

RESULTS

Fifteen patients were identified who met all inclusion criteria. Linear regression analysis plotted INR response at 24 hours versus dose of vitamin K adjusted for body weight. Pearson's product moment correlation (R = 0.85) indicated a significant relationship between INR response at 24 hours to an adjusted body weight dose of subcutaneous vitamin K (P = 0.0000523). A strong correlation (r = 0.69) also existed between INR response at 24 hours and the actual body weight dose of subcutaneous vitamin K (P = 0.004).

CONCLUSIONS

In overanticoagulated patients, variability in response to vitamin K may be explained by variability in body weight. Dosing vitamin K according to body weight may result in a more predictable INR response.

Granulocytic sarcoma of the head and neck: a case report

A rare case of granulocytic sarcoma of the head and neck region is presented to highlight its unusual clinical presentation and the difficulties encountered in its diagnosis. The risk factors, pathological findings, and treatment modalities are discussed to make head and neck surgeons aware of this condition, which can have a fatal outcome as happened in our case.

Time course of reversal of anticoagulant effect of warfarin by intravenous and subcutaneous phytonadione

BACKGROUND

Excessive anticoagulation increases the risk of hemorrhagic complications associated with oral anticoagulant therapy. Oral or parenteral phytonadione is used to reverse excessive anticoagulation. Intravenous (IV) phytonadione, while effective, is associated with a small risk of serious anaphylactic reactions. Subcutaneous (SC) administration is safer, but there is little information on its relative efficacy in small doses.

METHODS

Twenty-two patients with asymptomatic prolongation of prothrombin time were prospectively randomized and treated with 1 mg of phytonadione IV or 1 mg SC. Prothrombin time was measured at baseline and at 8 and 24 hours after phytonadione administration and expressed as international normalized ratio (INR).

RESULTS

Mean INR at baseline was 8.0 and 8.5 in the IV and SC groups, respectively (P = .70). At 8 hours, mean INR was 4.6 in the IV group and 8.0 in the SC group (P = .006), and at 24 hours, mean INR was 3.1 in the IV group and 5.0 in the SC group (P = .009). Mean decrease in INR 8 hours after administration of phytonadione was 3.4 in the IV group and 0.4 in the SC group (P = .02), and mean decrease in INR after 24 hours was 4.9 in the IV group and 3.4 in the SC group (P = .18).

CONCLUSIONS

For patients who are excessively anticoagulated with warfarin, small doses of SC phytonadione may not correct the INR as rapidly or as effectively as when administered IV. Higher doses must be considered for more rapid and complete reversal of anticoagulation by the SC route.

Safety of intramuscular influenza immunization among patients receiving long-term warfarin anticoagulation therapy

BACKGROUND

The effect of influenza vaccine on the prothrombin time (PT) among patients taking warfarin is unclear, as previous studies have shown conflicting results and the clinical significance of such a purported effect is uncertain. Moreover, to our knowledge, there are no data confirming the safety of intramuscular injections in patients receiving anticoagulant therapy with regard to possible local hematoma formation. We measured the effect of influenza vaccine on the PT among patients receiving long-term warfarin sodium therapy and evaluated the safety of intramuscular injections among them.

METHODS

Forty-one adult patients who were receiving anticoagulant therapy were given 0.5 mL of influenza vaccine intramuscularly. Prothrombin time and arm girth were measured at baseline and on days 3, 7, and 14 after immunization. Local pain and tenderness were assessed on a five-point scale. Patients and study nurses were blinded to all prior measurements. Differences between baseline PT and that at each subsequent visit and the maximal change in arm circumference from baseline were calculated for each patient. Mean, range, and 95% confidence intervals were calculated for the entire group.

RESULTS

There was no statistically significant change in PT between baseline and days 3, 7, and 14 after vaccination, and no significant change in arm circumference was noted. There were no clinically detectable local complications after intramuscular injection and no major or minor bleeding episodes after influenza vaccination.

CONCLUSIONS

Influenza vaccine has no significant effect on the PT in patients who are being treated with warfarin. Influenza vaccine can be administered intramuscularly to patients who are receiving anticoagulant therapy without the risk of local bleeding complications.

Precipitation reactions with Newcastle disease virus

Acid precipitated and detergent treated Newcastle disease virus (NDV) antigen was prepared and characterised using the agar gel precipitation (AGP) test. The detergent treated NDV antigen was used to screen antibodies to NDV and the results compared with the conventional haemagglutination inhibition (HI) test titres. AGP test could detect NDV antibodies in serum samples when the corresponding HI titres were 1:8 and above. Detergent treatment of Newcastle disease virus greatly reduced its haemagglutinating ability. Simultaneous detection of antibodies to NDV and infectious bursal disease virus in AGP test was attempted and found successful.

Transcription of a human neurotropic virus promoter in glial cells: effect of YB-1 on expression of the JC virus late gene

We have isolated a partial recombinant cDNA clone from a HeLa expression library which encodes a protein capable of binding to the central region of the human neurotropic JC virus (JCV) enhancer/promoter, termed the B region. Sequence analysis revealed a complete homology of the partial cDNA clone to the N-terminal region, of a previously described DNA-binding protein, termed YB-1. Band shift analyses have indicated that the bacterially produced YB-1 interacts specifically with the double-stranded B oligonucleotide as well as the corresponding single-stranded DNA fragment representing the early promoter sequence. Further analysis indicated that the YB-1 protein binds specifically to the C/T-rich sequence of the B domain, which is located in close proximity to the TATA box within the virus enhancer/promoter. Results from cotransfection experiments demonstrated that the full-length (YB-1) but not the partial cDNA enhances expression of the JCV late (JCVL) promoter in glial cells. Cointroduction into glial cells of a recombinant expressing the YB-1 and JCVL deletion mutants indicated that removal of the C/T-rich sequence of the B domain reduces the level of activation of the virus promoter by YB-1. Further cotransfection experiments revealed that the virus transactivating protein T antigen appears to diminish the ability of YB-1 to activate JCVL gene expression. RNA studies indicated that YB-1 is expressed in several cell types and tissues. Examination of YB-1 RNA from mouse brain at various stages of development revealed high levels of YB-1 RNA at early stages of development and lower levels at all subsequent developmental stages.

Late infantile neuronal ceroid lipofuscinosis: an ultrastructural investigation

Late infantile neuronal lipofuscinosis was confirmed by electron microscopy in this case. At magnifications above 100,000 a particular alternating linear pattern of the curvilinear bodies was found.

Long-term oral anticoagulant therapy: update on indications, therapeutic ranges, and monitoring

Oral anticoagulant therapy is used extensively in the treatment of deep venous thrombosis-pulmonary embolism and prevention of systemic thromboembolism. Adoption of the International Normalized Ratio system for the laboratory monitoring of therapy has solved the problems encountered with the variable sensitivities of the available thromboplastins in North America. Although in recent years the recommended intensity of treatment has been reduced for many indications, bleeding remains the most common side effect of long-term oral anticoagulation therapy. Several drugs interact with warfarin sodium, the most commonly used oral anticoagulant drug, and potentiate its effect, thereby increasing the risk of bleeding. However, awareness of potential drug interactions and careful monitoring to maintain patients within the recommended therapeutic ranges can minimize the risk of bleeding and lead to its safe use in most patients.

Perioperative prophylaxis of venous thromboembolism

Venous thromboembolism is an important cause of morbidity and mortality in hospitalized patients, causing 100,000 to 200,000 deaths per year in the United States. Patients undergoing surgery are at the highest risk of venous thromboembolism. The magnitude of this risk in a patient depends on the surgical procedure performed and the presence of other risk factors that predispose to venous thromboembolism. The clinical diagnosis of both deep vein thrombosis and pulmonary embolism is notoriously inaccurate. Furthermore, two thirds of all fatal pulmonary emboli cause death within 30 minutes of the embolic episode, leaving little time for diagnostic work-up and effective treatment. Prophylactic treatment for prevention of venous thromboembolism is therefore important in these patients, and several effective mechanical and chemical methods for this purpose are available. The pathogenesis of deep vein thrombosis in the surgical patients, the predisposing risk factors, and the available prophylactic modalities are discussed in this article. Recommendations for the use of various approaches in different risk categories are provided.