Direct delivery of functional proteins and enzymes to the cytosol using nanoparticle-stabilized nanocapsules

Intracellular protein delivery is an important tool for both therapeutic and fundamental applications. Effective protein delivery faces two major challenges: efficient cellular uptake and avoiding endosomal sequestration. We report here a general strategy for direct delivery of functional proteins to the cytosol using nanoparticle-stabilized capsules (NPSCs). These NPSCs are formed and stabilized through supramolecular interactions between the nanoparticle, the protein cargo, and the fatty acid capsule interior. The NPSCs are ~130 nm in diameter and feature low toxicity and excellent stability in serum. The effectiveness of these NPSCs as therapeutic protein carriers was demonstrated through the delivery of fully functional caspase-3 to HeLa cells with concomitant apoptosis. Analogous delivery of green fluorescent protein (GFP) confirmed cytosolic delivery as well as intracellular targeting of the delivered protein, demonstrating the utility of the system for both therapeutic and imaging applications.

Verification of dose calculation algorithms in a multi-layer heterogeneous phantom using films

The development of advanced radiation treatment techniques such as intensity modulated radiation therapy (IMRT) and volumetric intensity modulated arc therapy (VMAT) require more accurate dose calculation algorithms within the treatment planning systems (TPS) considering that the human body is composed of tissues of widely differing radiological properties and the characteristics of a therapeutic radiation treatment beam along a heterogeneous path will be different. The objective of this study was to evaluate the accuracy of 2D-isodose distributions predicted by pencil beam convolution algorithm (PBC) and anisotropic analytic algorithm (AAA) in a heterogeneous slab phantom composed of media equivalent to air, water and bone density. The measurements were done by using the films at multiple depths in the phantom for open field sizes 5 × 5 cm2 and 10 × 10 cm2. The results from this study indicated that the AAA had better agreement with the measurement compared to PBC for both the test field sizes at all selected depths; however, the limitation of AAA in predicting doses within and beyond low-density medium was observed, especially for a smaller field size (up to 32.7% and 34.0% for AAA and PBC, respectively). Furthermore, discrepancies up to -4.8% for AAA and -14.6% for PBC was seen in the high-density medium as well. Dose prediction errors by the AAA and PBC were more pronounced for a smaller test field size, especially in the low-density medium.

KEYWORDS

IMRT, dose calculation algorithms, Anisotropic Analytical Algorithm (AAA), Pencil Beam Convolution (PBC), Varian's Eclipse treatment planning system.

Cost and resource implications with serum angiogenic factor estimation in the triage of pre-eclampsia

OBJECTIVES

To analyse the economic and resource implications of using plasma soluble fms-like tyrosine kinase-1 s(Flt1) and placenta growth factor (PlGF) measurements in pre-eclampsia evaluation and management.

DESIGN

Retrospective cost analysis of our prospective cohort study.

SETTING

Boston, Massachusetts (USA).

POPULATION

Women (n = 176) presenting to the hospital at <34 weeks of gestation for evaluation of possible pre-eclampsia during 2009-10. Cases without complete cost or outcome data (n = 9) and re-enrolments (n = 18) were excluded.

METHODS

Modelled comparisons between the standard approach (combination of blood pressure, urinary protein excretion, alanine aminotransferase and platelet counts) and a novel approach (ratio of plasma sFlt1 and PlGF) using actual hospital data converted to 2012 US dollars in accordance with the Centers for Medicare and Medicaid Services.

MAIN OUTCOME MEASURES

Direct 2-week costs and resource use by groups having true or false positive and negative test results for adverse outcomes according to approach.

RESULTS

The improved specificity of the novel approach decreased the proportion of women falsely labelled as test-positive from 42.3% (34.4-50.2%) to 4.0% (0.85-7.15%) and increased the proportion correctly labelled as test-negative from 23.5% (16.7-30.3%) to 61.7% (53.9-69.5%). This could potentially reduce average per-patient costs by $1215. Substantial quantities of resources [47.2% (35.7-58.7%) of antenatal admissions and 72.5% (68.0-77.0%) of tests for fetal wellbeing] were unnecessarily used for women who were truly negative. A proportion of iatrogenic preterm deliveries among women with negative results was potentially avoidable representing further cost and resource savings.

CONCLUSIONS

Clinical use of the plasma sFlt1 and PlGF ratio improves risk stratification among women presenting for pre-eclampsia evaluation and has the potential to reduce costs and resource use.

Bone marrow negative visceral leishmaniasis in an adolescent male

Visceral Leishmaniasis or Kala Azar is endemic in certain regions of India. In endemic areas, the constellation of fever, progressive weight loss, weakness, pronounced splenomegaly, anemia, leukopenia, and hypergammaglobulinemia is highly suggestive of visceral leishmaniasis. Demonstration of the parasite in liver, splenic or bone marrow aspirates is confirmatory. We present a case in which Leishmania donovani (LD) bodies were demonstrated on splenic aspirate. We were unable to demonstrate LD bodies on bone marrow aspiration.

Chemoselective nanoporous membranes via chemically directed assembly of nanoparticles and dendrimers

Chemoselective nanoporous membranes: tunably porous membranes with embedded functionalities are generated using a template-free, chemically directed nanoparticle-dendrimer (NP-Den) network assembly. This approach provides a direction in the design of post-functionalizable nanoporous membranes for distinguishing both organic molecules and proteins with excellent chemo- and bioselectivity.

Differentiation of cancer cell type and phenotype using quantum dot-gold nanoparticle sensor arrays

We demonstrate rapid and efficient sensing of mammalian cell types and states using nanoparticle-based sensor arrays. These arrays are comprised of cationic quantum dots (QDs) and gold nanoparticles (AuNPs) that interact with cell surfaces to generate distinguishable fluorescence responses based on cell surface signatures. The use of QDs as the recognition elements as well as the signal transducers presents the potential for direct visualization of selective cell surface interactions. Notably, this sensor is unbiased, precluding the requirement of pre-knowledge of cell state biomarkers and thus providing a general approach for phenotypic profiling of cell states, with additional potential for imaging applications.

Array-based sensing of metastatic cells and tissues using nanoparticle-fluorescent protein conjugates

Rapid and sensitive methods of discriminating between healthy tissue and metastases are critical for predicting disease course and designing therapeutic strategies. We report here the use of an array of gold nanoparticle-green fluorescent protein elements to rapidly detect metastatic cancer cells (in minutes), as well as to discriminate between organ-specific metastases and their corresponding normal tissues through their overall intracellular proteome signatures. Metastases established in a new preclinical non-small-cell lung cancer metastasis model in athymic mice were used to provide a challenging and realistic testbed for clinical cancer diagnosis. Full differentiation between the analyte cell/tissue was achieved with as little as 200 ng of intracellular protein (~1000 cells) for each nanoparticle, indicating high sensitivity of this sensor array. Notably, the sensor created a distinct fingerprint pattern for the normal and metastatic tumor tissues. Moreover, this array-based approach is unbiased, precluding the requirement of a priori knowledge of the disease biomarkers. Taken together, these studies demonstrate the utility of this sensor for creating fingerprints of cells and tissues in different states and present a generalizable platform for rapid screening amenable to microbiopsy samples.

Reduction of Acute Anterior Shoulder Dislocation Using Intraarticular Lidocaine(IAL) and Stimson’s Technique

Introduction: Shoulder dislocation is common injury requiring urgent reduction. For the reason that patient is not nill orally and anesthetists are not available, reduction under intra venous anaesthesia is not possible. This study was aimed to evaluate the effectiveness of intraarticular lidocaine and stimson’s technique of shoulder dislocation, which could be performed without anesthetist and irrespective of nill orally status. Methods: A prospective observational study was performed from December 2009 to December 2010. Under all antiseptic precautions 20 ml of Lidocaine was injected intraarticularly and reduction was performed by Stimson’s technique. Visual Analogue Score, time for reduction and failure to reduction by this technique was recorded. Results: Out of 27 dislocations 22 were successfully reduced and remaining required added scapular manipulation. The mean VAS scor was 2.3±1.26 and the mean time of reduction was 17.96±1.9 minutes. Conclusion: Stimson’s method with Intraarticular Lidocaine is effective, safe, less costly and can be performed in periphery where anesthetist and monitoring facilities are not available. DOI: http://dx.doi.org/10.3126/mjsbh.v10i1.6406 Medical Journal of Shree Birendra Hospital Jan-June 2011 10(1) 6-8

OS094. Subclinical left ventricular dysfunction in preeclamptic women with preserved left ventricular ejection fraction: A 2D speckle tracking imaging study

INTRODUCTION

Patients with preeclampsia are at risk for cardiovascular disease [1,2]. Changes in cardiac function are subtle in preeclampsia and are quantitatively difficult with conventional imaging. Strain measurements using speckle-tracking echocardiography have been used to sensitively quantifyabnormalities in other disease settings [3].

OBJECTIVES

The objective of this study was to evaluate changes in myocardial strain using speckle tracking echocardiography in women with and without preeclampsia. We hypothesized that global left systolic strain measures would prove more sensitive than conventional left ventricular ejection fraction in detecting early changes in systolic LV function manifesting as subclinical disease prior to overt progression.

METHODS

We evaluated the feasibility and sensitivity of strain imaging using speckle tracking echocardiography. Thirty-six women were enrolled in this pilot study; 28 were analyzed: 11 with preeclampsia and 17 without preeclampsia. Echocardiographic Ejection fraction and global peak longitudinal ,radial and circumferential strain were measured.

RESULTS

Global Median longitudinal strain was significantly worsened in women with preeclampsia compared to women without preeclampsia (P<0.0001). Similar results were observed for global radial strain (P=0.006) and circumferential strain (P=0.03). There was no significant difference in ejection fraction between the groups (P=0.52) (Table 1). Data are presented as median (interquartile range).

CONCLUSION

Myocardial strain imaging using speckle tracking is more sensitive than left ventricular ejection fraction to detect differences in left ventricular systolic function in women with and without preeclampsia.

Gold nanoparticle-polymer/biopolymer complexes for protein sensing

Nanoparticle-based sensor arrays have been used to distinguish a wide range of biomolecular targets through pattern recognition. Such biosensors require selective receptors that generate a unique response pattern for each analyte. The tunable surface properties of gold nanoparticles make these systems excellent candidates for the recognition process. Likewise, the metallic core makes these particles fluorescence superquenchers, facilitating transduction of the binding event. In this report we analyze the role of gold nanoparticles as receptors in differentiating a diversity of important human proteins, and the role of the polymer/biopolymer fluorescent probes for transducing the binding event. A structure-activity relationship analysis of both the probes and the nanoparticles is presented, providing direction for the engineering of future sensor systems.

Surface functionalization of nanoparticles for nanomedicine

Control of interactions between nanoparticles and biosystems is essential for the effective utilization of these materials in biomedicine. A wide variety of nanoparticle surface structures have been developed for imaging, sensing, and delivery applications. In this research Highlight, we will emphasize advances in tailoring nanoparticle interfaces for implementation in nanomedicine.

Monolayer coated gold nanoparticles for delivery applications

Gold nanoparticles (AuNPs) provide attractive vehicles for delivery of drugs, genetic materials, proteins, and small molecules. AuNPs feature low core toxicity coupled with the ability to parametrically control particle size and surface properties. In this review, we focus on engineering of the AuNP surface monolayer, highlighting recent advances in tuning monolayer structures for efficient delivery of drugs and biomolecules. This review covers two broad categories of particle functionalization, organic monolayers and biomolecule coatings, and discusses their applications in drug, DNA/RNA, protein and small molecule delivery.

Control of surface tension at liquid-liquid interfaces using nanoparticles and nanoparticle-protein complexes

Subtle changes in the monolayer structure of nanoparticles (NPs) influence the interfacial behavior of both NPs and NP-protein conjugates. In this study, we use a series of monolayer-protected gold NPs to explore the role of particle hydrophobicity on their dynamic behavior at the toluene-water interface. Using dynamic surface tension measurements, we observed a linear decrease in the meso-equilibrium surface tension (γ) and faster dynamics as the hydrophobicity of the ligands increases. Further modulation of γ is observed for the corresponding NP-protein complexes at the charge-neutralization point.

Imaging assessment of desmoid tumours in familial adenomatous polyposis: is state-of-the-art 1.5 T MRI better than 64-MDCT?

OBJECTIVE

Desmoid tumour is a common extraintestinal manifestation of patients with familial adenomatous polyposis (FAP) who have undergone prophylactic colectomy. We aimed to determine whether MRI provides equivalent or better assessment of desmoid tumours than CT, the current first-line investigation.

METHODS

Following ethics approval and informed consent, FAP patients with known desmoid tumour underwent contrast-enhanced 64-slice multidetector CT (MDCT) and 1.5 T MRI (incorporating T(1) weighted, T(2) weighted, short tau inversion-recovery and T(1) weighted with contrast, axial, sagittal and coronal sequences). The number, site, size, local extent, tumour signal intensity and desmoid-to-aorta enhancement ratio were analysed.

RESULTS

MRI identified 23 desmoid tumours in 9 patients: 9 intra-abdominal desmoid (IAD) tumours, 10 abdominal wall desmoid (AWD) tumours and 4 extra-abdominal desmoid (EAD) tumours. CT identified only 21 desmoids; 1 EAD and 1 AWD were not identified. The two modalities were equivalent in terms of defining local extent of desmoid. Five IAD tumours involved the bowel, six caused ureteric compression and none compromised the proximal superior mesenteric artery. There was no difference in median desmoid size: 56.7 cm(2) (range 2-215 cm(2)) on MDCT and 56.3 cm(2) (3-215 cm(2)) on MRI (p=0.985). The mean MRI enhancement ratio, at 1.12 (standard deviation 0.43), was greater than the CT enhancement ratio, which was 0.48 (0.16) (p<0.0001). High signal intensity on T(2) MRI was associated with increased MRI enhancement ratio (p=0.006).

CONCLUSIONS

MRI is at least equivalent (and may be superior) to MDCT for the detection of desmoid tumours in FAP. Coupled with the advantage of avoiding radiation, it should be considered as the primary imaging modality for young FAP patients.

Use of human urine in phytoplankton production as a tool for ecological sanitation

Measurements of primary productivity of phytoplankton and enumeration of the counts of coliform and heterotrophic bacteria (HB) were made in the water of 12 experimental tanks used for 3 treatments and control in triplicate as follows: (a) fresh human urine (0.02%), (b) stored human urine (0.02%), (c) mixed urine of fresh and stored human urine (0.02%) and (d) control without input of urine. The gross primary productivity of phytoplankton was highest in the stored urine treated tanks (508 mg C m(-2) h(-1)) followed by fresh urine (353 mg C m(-2) h(-1)), mixed urine (303 mg C m(-2) h(-1)) and control (215 mg C m(-2) h(-1)). Similar was the response of net primary production of phytoplankton. The mean count of HB observed in stored urine fed tanks was significantly higher (59-184%) than the remaining urine fed treatments. The mean count of Escherichia coli did not differ from urine treated tanks to control implying the good quality of water. The concentration of dissolved oxygen of water (7.6 to 12.8 mg L(-1)) in these tanks remained satisfactory for aquaculture. The mean concentration of ammonium-N observed in fresh urine treated tanks was more than 10 times higher than the remaining treatments employed. In contrast, the level of phosphate and electrical conductivity in the stored urine treated tanks were significantly higher than the remaining treatments. It is proposed that stored urine with a significantly reduced load of E. coli might be an effective low cost liquid fertilizer for algal biomass production.

Mechanism of anti-angiogenic property of gold nanoparticles: role of nanoparticle size and surface charge

Discovering therapeutic inorganic nanoparticles (NPs) is evolving as an important area of research in the emerging field of nanomedicine. Recently, we reported the anti-angiogenic property of gold nanoparticles (GNPs): It inhibits the function of pro-angiogenic heparin-binding growth factors (HB-GFs), such as vascular endothelial growth factor 165 (VEGF165) and basic fibroblast growth factor (bFGF), etc. However, the mechanism through which GNPs imparts such an effect remains to be investigated. Using GNPs of different sizes and surface charges, we demonstrate here that a naked GNP surface is required and core size plays an important role to inhibit the function of HB-GFs and subsequent intracellular signaling events. We also demonstrate that the inhibitory effect of GNPs is due to the change in HB-GFs conformation/configuration (denaturation) by the NPs, whereas the conformations of non-HB-GFs remain unaffected. We believe that this significant study will help structure-based design of therapeutic NPs to inhibit the functions of disease-causing proteins.

Status Epilepticus in Children

Status epilepticus (SE) is a life-threatening emergency that requires prompt treatment, including basic neuroresuscitation principles (the ABCs), antiepileptic drugs to stop the seizure and identification of etiology. It results from an inability to normally abort an isolated seizure either due to ineffective inhibition, or due to abnormally persistent excessive excitation. Symptomatic SE is more common in younger children and the likely etiology depends on the age of the child. Treating the precipitating cause may prevent ongoing neurologic injury and facilitates seizure control. Benzodiapenes, phenytoin and phenobarbital form the mainstay of treatment. A systematic treatment regimen, planned in advance, is needed, including one for refractory status epilepticus (RSE). Patient education and home management of seizures is important to reduce the morbidity and mortality associated with SE.

Electrostatic selectivity in protein-nanoparticle interactions

The binding of bovine serum albumin (BSA) and β-lactoglobulin (BLG) to TTMA (a cationic gold nanoparticle coupled to 3,6,9,12-tetraoxatricosan-1-aminium, 23-mercapto-N,N,N-trimethyl) was studied by high-resolution turbidimetry (to observe a critical pH for binding), dynamic light scattering (to monitor particle growth), and isothermal titration calorimetry (to measure binding energetics), all as a function of pH and ionic strength. Distinctively higher affinities observed for BLG versus BSA, despite the lower pI of the latter, were explained in terms of their different charge anisotropies, namely, the negative charge patch of BLG. To confirm this effect, we studied two isoforms of BLG that differ in only two amino acids. Significantly stronger binding to BLGA could be attributed to the presence of the additional aspartates in the negative charge domain for the BLG dimer, best portrayed in DelPhi. This selectivity decreases at low ionic strength, at which both isoforms bind well below pI. Selectivity increases with ionic strength for BLG versus BSA, which binds above pI. This result points to the diminished role of long-range repulsions for binding above pI. Dynamic light scattering reveals a tendency for higher-order aggregation for TTMA-BSA at pH above the pI of BSA, due to its ability to bridge nanoparticles. In contrast, soluble BLG-TTMA complexes were stable over a range of pH because the charge anisotropy of this protein at makes it unable to bridge nanoparticles. Finally, isothermal titration calorimetry shows endoenthalpic binding for all proteins: the higher affinity of TTMA for BLGA versus BLGB comes from a difference in the dominant entropy term.

Engineering the nanoparticle-protein interface: applications and possibilities

Covalent and non-covalent conjugation of proteins to nanoparticles provides access to functional hybrid systems with applications in biotechnology, medicine, and catalysis. The creation of effective conjugates requires the retention of protein structure and function, a challenging task. In this review we discuss successes, challenges and opportunities in the area of protein-nanoparticle bioconjugation.

Investigation of Burkholderia cepacia complex in septicaemic patients in a tertiary care hospital, India

Burkholderia cepacia complex (BCC) is being increasingly recognized as an important pathogen of humans. During the year 2007-8, 39 putative BCC isolates were obtained from 21 cases and subjected to recA PCR RFLP. Twenty-four isolates were confirmed as Burkholderia cenocepacia IIIA (nineteen isolates, recA PCR RFLP type G and five isolates, recA PCR RFLP type I), six were confirmed as B. cepacia (recA PCR RFLP type E). BCC were isolated from inpatients of different wards of Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh with increased isolation from children admitted to different wards of Advanced Pediatric Centre (11/21 cases). BCC isolates are often resistant to most commonly used antibiotics and an early use of effective antimicrobial therapy can decrease morbidity and mortality.

Modulation of enzyme-substrate selectivity using tetraethylene glycol functionalized gold nanoparticles

Tetraethylene glycol (TEG) functionalized gold nanoparticles with 2 nm core diameters (AuTEG) enhance alpha-chymotrypsin (ChT) enzyme activity in a substrate-selective fashion. We explored the hydrolysis of four different substrates and observed a marked increase in activity with the most hydrophobic substrate N-succinyl-alanine-alanine-proline-phenylalanine- p-nitroanilide (TP), while the other substrates remain virtually unaffected by the AuTEG 'crowding effect' in solution. The enhancement in catalysis is indicated by an increase in K(cat)/K(m) as obtained from Lineweaver-Burk analysis and we hypothesize it to arise from a macromolecular crowding effect analogous to that observed with high molecular weight poly(ethylene glycol) (PEG) polymers.