BanAn Khaw - Academia.edu (original) (raw)

Papers by BanAn Khaw

Research paper thumbnail of Anin vitrodemonstration of overcoming drug resistance in SKOV3 TR and MCF7 ADR with targeted delivery of polymer pro-drug conjugates

Journal of Drug Targeting, 2017

Drug resistance is a common phenomenon that occurs in cancer chemotherapy. Delivery of chemothera... more Drug resistance is a common phenomenon that occurs in cancer chemotherapy. Delivery of chemotherapeutic agents as polymer pro-drug conjugates (PPDCs) pretargeted with bispecific antibodies could circumvent drug resistance in cancer cells. To demonstrate this approach to overcome drug resistance, Paclitaxel (Ptxl) resistant SKOV3 TR human ovarian-and doxorubicin (Dox) resistant MCF7 ADR human mammary-carcinoma cell lines were used. Pre-targeting overexpressed biotin or HER2/neu receptors on cancer cells was conducted by biotinylated anti-DTPA or Anti-HER2/neu affibody-anti-DTPA Fab bispecific antibody complexes. The targeting PPDCs are either D-Dox-PGA or D-Ptxl-PGA. Cytotoxicity studies demonstrate that the pretargeted approach increases cytotoxicity of Ptxl or Dox in SKOV3 TR or MCF7 ADR resistant cell lines by 5.4 and 27 times respectively. Epifluorescent microscopy-used to track internalization of D-Dox-PGA and Dox in MCF7 ADR cells-shows that the pretargeted delivery of D-Dox-PGA resulted in a 2 to 4 fold increase in intracellular Dox concentration relative to treatment with free Dox. The mechanism of internalization of PPDCs is consistant with endocytosis. Enhanced drug delivery and intracellular retention following pretargeted delivery of PPDCs resulted in greater tumor cell toxicity in the current in vitro studies.

Research paper thumbnail of Smooth muscle cell proliferation index correlates with 111In-labeled antibody Z2D3 uptake in a transplant vasculopathy swine model

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2005

Transplant vasculopathy is a major cause of morbidity and mortality in heart transplantation. The... more Transplant vasculopathy is a major cause of morbidity and mortality in heart transplantation. The proliferation of coronary vascular smooth muscle cells is a hallmark of transplant vasculopathy. The goal of this study was to detect coronary vascular smooth muscle cell proliferation in a swine model by imaging regions of uptake of a monoclonal antibody (Z2D3) labeled with 111In. Coronary-to-right carotid artery transplantation was performed in 10 Yucatan minipigs with coronary arteries from farm pigs as donors. In 5 of these experiments, the right carotid artery was also grafted to the left carotid artery as a homograft. In 1 farm pig, the left and right carotid arteries were switched. After 44 +/- 22 days (mean +/- SE), animals were injected with 5-bromo-2-deoxyuridine (BrDU) and 111In-Z2D3 F(ab')2. Approximately 24 h later, the pigs underwent planar and SPECT imaging. After the imaging session, the pigs were sacrificed and the vessels were removed. Ex vivo autoradiography of al...

Research paper thumbnail of p-Nitrophenylcarbonyl-PEG-PE-liposomes: fast and simple attachment of specific ligands, including monoclonal antibodies, to distal ends of PEG chains via p-nitrophenylcarbonyl groups

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2001

We have attempted to simplify the procedure for coupling various ligands to distal ends of liposo... more We have attempted to simplify the procedure for coupling various ligands to distal ends of liposome-grafted polyethylene glycol (PEG) chains and to make it applicable for single-step binding of a large variety of a primary amino group-containing substances, including proteins and small molecules. With this in mind, we have introduced a new amphiphilic PEG derivative, p-nitrophenylcarbonyl-PEG-1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (pNP-PEG-DOPE), synthesized by reaction of DOPE with excess of bis(p-nitrophenylcarbonyl)-PEG in a chloroform/triethylamine mixture. pNP-PEG-DOPE readily incorporates into liposomes via its PE residue, and easily binds primary amino group-containing ligands via its waterexposed pNP groups, forming stable and non-toxic urethane (carbamate) bonds. The reaction between the pNP group and the ligand amino group proceeds easily and quantitatively at pH around 8.0, and remaining free pNP groups are promptly eliminated by spontaneous hydrolysis. Therefore, pNP-PEG-DOPE could serve as a very convenient tool for protein attachment to the distal ends of liposome-grafted PEG chains. To investigate the applicability of the suggested protocol for the preparation of long-circulating targeted liposomes, we have coupled several proteins, such as concanavalin A (ConA), wheat germ agglutinin (WGA), avidin, monoclonal antimyosin antibody 2G4 (mon2G4), and monoclonal antinucleosome antibody 2C5 (mon2C5) to PEG-liposomes via terminal pNP groups and studied whether the specific activity of these immobilized proteins is preserved. The method permits the binding of several dozens protein molecules per single 200 nm liposome. All bound proteins completely preserve their specific activity. Lectin-liposomes are agglutinated by the appropriate polyvalent substrates (mannan for ConA-liposomes and glycophorin for WGA-liposomes); avidin-liposomes specifically bind with biotin-agarose; antibody-liposomes demonstrate high specific binding to the substrate monolayer both in the direct binding assay and in ELISA. A comparison of the suggested method with the method of direct membrane incorporation was made. The effect of the concentration of liposome-grafted PEG on the preservation of specific protein activity in different coupling protocols was also investigated. It was also shown that pNP-PEG-DOPE-liposomes with and without attached ligands demonstrate increased stability in mouse serum.

Research paper thumbnail of Quo Vadis Radioimmune Imaging?—Reply

Journal of Nuclear Medicine, Aug 1, 1990

Sensitivitywas achieved with higher doses of antibody; * Sensitivity of 29% for 2.5 mg of antibod... more Sensitivitywas achieved with higher doses of antibody; * Sensitivity of 29% for 2.5 mg of antibody (n = 4) and 74% for 20 mg (n = 6);  § The false-positive rateinthisstudywas 50%. ft H = reference from Haipem et al. and 0 = reference from DeNardoand DeNardo. 3 multicenter trial, sensitivity was 94% for 202 patients with transmural infarction and 84% for 57 patients with non transmuralinfarction(6). In the caseofradioimmuno imaging for infection, the data are sparse. Similarly, imaging of throm bus alsogetsmixed reviews. Concerningthe important point raised about the number and affinity of binding sites for radioimmune imaging. Dr. Denardo states(7): â€oeIn the absenceof heterogeneousexpres sion ofthe antigen or obstacles to delivery of the antibody to the cell membrane antigenic sites, the iO'@to iO'@antibody molecules can be accumulated in 1 gram of cancer tissue.― This suggests that up to 250 @g of antibody (25% of the injecteddoseafteradministrationof 1.0mgof antibody)could be concentrated in a singlegram of tumor. These attractive assumptions, unfortunately, have not been borne out by din ical experience. In practice, lesions rarely concentrate more than 0.01%ofthe injecteddose. Weagreewiththe authorsthat the relativemassofantibody administered to a mouse or man is not the sole determinant for the different levelsof accumulation of radiolabeledanti body in tumors in these species.Imagingstudies performed following radioimmune therapy, where large amounts of pro tein and radioactivity are administered, rarely identify lesions

Research paper thumbnail of Acute myocardial infarct imaging with indium-111-labeled monoclonal antimyosin Fab

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1987

Indium-111 monoclonal antimyosin Fab scintigraphy was used to detect myocardial necrosis in 52 of... more Indium-111 monoclonal antimyosin Fab scintigraphy was used to detect myocardial necrosis in 52 of 54 patients (96.3%) with acute myocardial infarction. Infarcts were visualized when coronary arteries were persistently occluded (n = 10), became patent after thrombolysis (n = 33), or became patent after spontaneous reperfusion (n = 7). Posteroinferolateral visualizations were obtained in two patients with clinical and enzymatic evidence of infarction but normal electrocardiograms. Of the two patients in whom no infarcts were visualized, one had an anterior myocardial infarct. This patient underwent successful thrombolytic therapy, with attendant minimization of creatine kinase release. The other patient had a small, nonreperfused inferior myocardial infarct. Five patients with a history of remote infarction and acute necrosis showed antimyosin uptake only in regions concordant with the acute episodes of infarction, and radiolabeled antimyosin Fab localized in neither old infarcts nor ...

Research paper thumbnail of Monoclonal Antibodies Specific for Cardiac Myosin: In Vivo and in Vitro Diagnostic Tools in Myocardial Infarction

Research paper thumbnail of Relation of immediate and delayed thallium-201 distribution to localization of iodine-125 antimyosin antibody in acute experimental myocardial infarction

The American Journal of Cardiology, 1983

Thallium-201 (TI-201) distribution in acute experimental myocardial infarction (MI) (n = 18) was ... more Thallium-201 (TI-201) distribution in acute experimental myocardial infarction (MI) (n = 18) was compared with cardiac-specific antimyosin Fab (AM-Fab) uptake, a specific marker for myocardial necrosis. When antimyosin was injected 4 hours after ligation with TI-201 administered 23 hours 55 minutes later and measurement of myocardial distribution determined 5 minutes after intravenous administration of TI-201, (1) TI-201 distribution closely correlated with microsphere regional blood flow, and (2) an inverse exponential relation to iodine-125 (I-125) AM-Fab uptake was apparent. In another group of 4 animals, TI-201 and AM-Fab were administered intravenously 4 hours after MI, and 36 hours later myocardial distribution was measured. This delayed TI-201 distribution had a close inverse linear correlation with I-125 AM-Fab uptake. This inverse linear relation also was apparent in 28-hour-old MIs in dogs (n = 4) where collateral circulation had been established. TI-201 was administered intravenously at 27 hours after MI, and TI-201 distribution was determined 1 hour later. The present study demonstrated that whereas immediate TI-201 distribution is flow-limited, delayed TI-201 distribution is a marker of cell viability which, due to prolonged circulation time and redistribution, is not flow-limited.

Research paper thumbnail of Reagents and Methods for Bispecific Antibody-Based Binding of Target Molecules

Research paper thumbnail of Diagnosis of acute myocardial infarction by detection of circulating cardiac myosin light chains

The American Journal of Cardiology, 1984

Research paper thumbnail of Rapid noninvasive detection of experimental atherosclerotic lesions with novel 99m Tc-labeled diadenosine tetraphosphates

Proceedings of the National Academy of Sciences, 1998

The development of a noninvasive imaging procedure for identifying atherosclerotic lesions is ext... more The development of a noninvasive imaging procedure for identifying atherosclerotic lesions is extremely important for the clinical management of patients with coronary artery and peripheral vascular disease. Although numerous radiopharmaceuticals have been proposed for this purpose, none has demonstrated the diagnostic accuracy required to replace invasive angiography. In this report, we used the radiolabeled purine analog, 99m Tc diadenosine tetraphosphate (Ap 4 A; AppppA, P 1 , P 4 -di(adenosine-5′)-tetraphosphate) and its analogue 99m Tc AppCHClppA for imaging experimental atherosclerotic lesions in New Zealand White rabbits. Serial gamma camera images were obtained after intravenous injection of the radiolabeled dinucleotides. After acquiring the final images, the animals were sacrificed, ex vivo images of the aortas were recorded, and biodistribution was measured. 99m Tc-Ap 4 A and 99m Tc AppCHClppA accumulated rapidly in atherosclerotic abdominal aorta, and lesions were clearl...

Research paper thumbnail of Workload policy for Northeastern University

Research paper thumbnail of Immunoassay technique using multispecific molecules

Research paper thumbnail of Gamma imaging of atherosclerotic plaques

Current Cardiovascular Imaging Reports, 2009

ABSTRACT Noninvasive gamma imaging of atherosclerotic plaques targets various metabolic aspects o... more ABSTRACT Noninvasive gamma imaging of atherosclerotic plaques targets various metabolic aspects of atherogenesis. Vascular endothelial dysfunction or denudation resulting in the expression of adhesion molecules that attract inflammatory cells and increased vascular permeability has also been targeted. Enzymes and molecules associated with apoptosis of these inflammatory cells have provided additional targets, such as oxidized low-density lipoprotein, matrix metalloproteinases, and phosphatidylserine. In late atherosclerotic lesions, the lipid core as well as proliferating smooth muscle cells have been imaged successfully. Platelets and fibrin deposition may also be targeted to demonstrate thrombosis in plaque rupture or erosion. However, no unimodal approach can diagnose plaque vulnerability. It will require multi-modal, multitasking approaches for molecular diagnostic prediction of plaque vulnerability and impending rupture. Existing experimental and clinical gamma imaging applications in atherosclerotic lesion imaging are reviewed. Improvement by signal amplification to image small lesion and the concept of multimodal applications are introduced.

Research paper thumbnail of Monoclonal Antibody to Cardiac Myosin: Imaging of Experimental Myocardial Infarction

Hybridoma, 1984

Monoclonal antibody R11D10 to human cardiac myosin, which also cross-reacted with canine cardiac ... more Monoclonal antibody R11D10 to human cardiac myosin, which also cross-reacted with canine cardiac myosin, was used to demonstrate in vivo localization and visualization by gamma scintigraphy of experimental myocardial infarction. R111)10 Fab with a Ka of 5 x 108 M_1 was labeled with technetium-99m ("mTc) by the dithionite reduction method of technetium pertechnetate, via a bifunctional chelating agent, diethylene triamine pentaacetic acid (DTPA). Uptake of 99mTc R11D10 Fab in the infarct can be visualized as early as 2 h after intravenous administration. Comparison of Rl 11)10 uptake to thallium-201, an analogue of potassium which is sequestered by normal myocardium, showed an inverse relation (r =-0.75,-0.87,-0.89), similar to that obtained with l2sI labeled polyclonal antimyosin Fab. Ratios of Rl 11)10 Fab in the infarct to normal myocardium were as high as 30:1 where access of antibody to antigen was not blood flow limited. However, with severe blood-flow restriction, the ratios were lower at about 10:1. Despite the theoretical limitation of a single epitope per myosin molecule available for binding by Rl II) 10 Fab, the immense excess of myosin in the infarcted myocardium allowed adequate concentration of radiolabeled R11D10 for visualization of the infarct by external gamma scintiscanning.

Research paper thumbnail of Targeting the Pathological Myocardium

Biomedical Aspects of Drug Targeting, 2002

The rationale for targeting the pathological myocardium is to enable development of better diagno... more The rationale for targeting the pathological myocardium is to enable development of better diagnostic modalities or to enhance therapeutic interventions. Since the heart is an end-differentiated organ that has no substantial regenerative properties, any injury to the heart could potentially lead to high morbidity and mortality. The causes of myocardial injury are varied. Acute myocardial infarction results in oncotic myocardial cell death, whereas cardiomyopathies are now believed to be associated primarily with apoptotic myocardial cell death. If these myocardial disorders can be targeted specifically for early diagnosis, then morbidity and mortality may be reduced and novel therapeutic interventions may result in decreasing the injury to the heart. This chapter will focus primarily on targeting the oncotic myocardium. Targeting the apoptotic myocardium will not be considered in detail, but an introduction to the latest advances will be provided.

Research paper thumbnail of Targeting Atherosclerotic Plaques

Biomedical Aspects of Drug Targeting, 2002

Clinical imaging of atherosclerotic plaques is based on anatomical demonstration of the narrowing... more Clinical imaging of atherosclerotic plaques is based on anatomical demonstration of the narrowing of the involved artery (1). Angioscopy (2) and intravascular ultrasound (3) can demonstrate the precise location of the lesions, the extent of luminal narrowing and plaque thickening. However, both methods are invasive and cannot provide the composition or the metabolic status of the atherosclerotic lesion (4). Plaques rich in macrophages and foam cells may denote high risk of plaque rapture (5) whereas fibrous plaques may denote slowly emergent lesions. Lesions rich in actively proliferating smooth muscle cells may be an indication of accelerated luminal diameter reduction (6). Other targets that might have potential applications may be associated with neoantigens that are expressed due to microvascular injury inherent in atherogenesis. Therefore, targeting macrophage, foam cell hyper-accumulation or hyperactivity intravascularly, neoexpression or hyperexpression of various vascular adhesion molecules, or the metabolites that may be incorporated into the cellular components of the atherosclerotic lesions may provide novel and specific diagnostic and therapeutic applications.

Research paper thumbnail of Radionuclide Imaging of the Synthetic Smooth Muscle Cell Phenotype in Experimental Atherosclerotic Lesions

Trends in Cardiovascular Medicine, 1996

Hypertrophic stimufi induce tmnsforming growth factor-beta 1 expressionin rat ventricular myocyte... more Hypertrophic stimufi induce tmnsforming growth factor-beta 1 expressionin rat ventricular myocytes. J Clin Invest 94:147& 1476. ThaikCM, CafderoneA, Takahashi N, Cheng,et af.: 1995.Effects of inflammatorycytokines on growth and growth factor expressionin cardiac myocytesand fibroblasts[abst]. Cir-culation92:1-569.

Research paper thumbnail of Palmitoyl Ascorbate Liposomes and Free Ascorbic Acid: Comparison of Anticancer Therapeutic Effects Upon Parenteral Administration

Pharmaceutical Research, 2011

To evaluate and compare anticancer therapeutic effect of palmitoyl ascorbate liposomes (PAL) and ... more To evaluate and compare anticancer therapeutic effect of palmitoyl ascorbate liposomes (PAL) and free ascorbic acid (AA). Liposomes incorporating palmitoyl ascorbate (PA) were prepared and evaluated for PA content by HPLC. To elucidate mechanism of action of cell death in vitro, effect of various H(2)O(2) scavengers and metal chelators on PA-mediated cytotoxicity was studied. Effect of various combinations of PAL and free AA on in vitro cytotoxicity was evaluated on 4T1 cells. In vivo, PAL formulation was modified with polyethylene glycol; effect of PEGylation on in vitro cytotoxicity was evaluated. Biodistribution of PEG-PAL formulation was investigated in female Balb/c mice bearing murine mammary carcinoma (4T1 cells). In vivo anticancer activity of PEG-PAL (PEG-PAL equivalent to 20 mg/kg of PA injected intravenously on alternate days) was compared with free AA therapy in same model. PEG-PAL treatment was significantly more effective than free AA treatment in slowing tumor growth. Nanoparticle formulations incorporating PA can kill cancer cells in vitro. The mechanism of PA cytotoxicity is based on production of extracellular reactive oxygen species and involves intracellular transition metals.

Research paper thumbnail of Targeting very small model lesions pretargeted with bispecific antibody with 99mTc-labeled high-specific radioactivity polymers

Nuclear Medicine Communications, 2010

Background Two-step targeting with bispecific antibody and 99m Tc-labeled high-specific radioacti... more Background Two-step targeting with bispecific antibody and 99m Tc-labeled high-specific radioactivity polymers was used for molecular imaging of two very small model lesions in rats. Methods and results Sprague-Dawley rats (group I) were injected with surrogate antigen-coated beads (SA beads) in the right hind leg or unmodified beads in the contralateral hind leg. In group II, femoral artery de-endothelialization was induced in the left hind leg and sham operation was performed in the contralateral hind leg. Bispecific antibody Z 2 D 3 F(ab 0) 2-anti-DTPA F(ab 0) 2 was injected intravenously 24 h after SAB injection or 1 week after endothelial denudation. 99m Tc-labeled polymers were injected intravenously 24 h later and c-images obtained at 2 and 24 h in group I or approximately 2.5 h in group II. Lesions were visualized by 2 h. In group I, SA beads-specific uptake in muscles was significantly greater than with unmodified beads (P < 0.015). In group II, lesions were visualized by 2.5 h after radiopolymer injection with uptake activity 2.1 ± 0.6 times greater than in the contralateral side from in-vivo images (P < 0.004) and 1.8 ± 0.7 times by c-scintillation counting (P < 0.04). Conclusion Pretargeting with Z 2 D 3 bispecific antibody for the localization of radiolabeled polymers enabled successful in-vivo c-imaging of very small lesions in two rat models of extravascular and intravascular targets. Biodistribution data confirmed that pretargeting with bispecific antibody enabled targeted visualization of two different very small model lesions by in-vivo c-imaging. Nucl Med Commun 31:320-327

Research paper thumbnail of Apoptosis in Myocytes in End-Stage Heart Failure

New England Journal of Medicine, 1996

Background Heart failure can result from a variety of causes, including ischemic, hypertensive, t... more Background Heart failure can result from a variety of causes, including ischemic, hypertensive, toxic, and inflammatory heart disease. However, the cellular mechanisms responsible for the progressive deterioration of myocardial function observed in heart failure remain unclear and may result from apoptosis (programmed cell death). Methods We examined seven explanted hearts obtained during cardiac transplantation for evidence of apoptosis. All seven patients had severe chronic heart failure: four had idiopathic dilated cardiomyopathy, and three had ischemic cardiomyopathy. DNA fragmentation (an indicator of apoptosis) was identified histochemically by in situ end-labeling as well as by agarose-gel electrophoresis of end-labeled DNA. Myocardial tissues obtained from four patients who had had a myocardial infarction one to two days previously were used as positive controls, and heart tissues obtained from four persons who died in motor vehicle accidents were used as negative controls for the end-labeling studies. Results Hearts from all four patients with idiopathic dilated cardiomyopathy and from one of the three patients with ischemic cardiomyopathy had histochemical evidence of DNA fragmentation. All four myocardial samples from patients with dilated cardiomyopathy also demonstrated DNA laddering, a characteristic of apoptosis, whereas this was not seen in any of the samples from patients with ischemic cardiomyopathy. Histologic evidence of apoptosis was also observed in the central necrotic zone of acute myocardial infarcts, but not in myocardium remote from the infarcted zone. Rare isolated apoptotic myocytes were seen in the myocardium from the four persons who died in motor vehicle accidents. Conclusions Loss of myocytes due to apoptosis occurs in patients with end-stage cardiomyopathy and may contribute to progressive myocardial dysfunction.

Research paper thumbnail of Anin vitrodemonstration of overcoming drug resistance in SKOV3 TR and MCF7 ADR with targeted delivery of polymer pro-drug conjugates

Journal of Drug Targeting, 2017

Drug resistance is a common phenomenon that occurs in cancer chemotherapy. Delivery of chemothera... more Drug resistance is a common phenomenon that occurs in cancer chemotherapy. Delivery of chemotherapeutic agents as polymer pro-drug conjugates (PPDCs) pretargeted with bispecific antibodies could circumvent drug resistance in cancer cells. To demonstrate this approach to overcome drug resistance, Paclitaxel (Ptxl) resistant SKOV3 TR human ovarian-and doxorubicin (Dox) resistant MCF7 ADR human mammary-carcinoma cell lines were used. Pre-targeting overexpressed biotin or HER2/neu receptors on cancer cells was conducted by biotinylated anti-DTPA or Anti-HER2/neu affibody-anti-DTPA Fab bispecific antibody complexes. The targeting PPDCs are either D-Dox-PGA or D-Ptxl-PGA. Cytotoxicity studies demonstrate that the pretargeted approach increases cytotoxicity of Ptxl or Dox in SKOV3 TR or MCF7 ADR resistant cell lines by 5.4 and 27 times respectively. Epifluorescent microscopy-used to track internalization of D-Dox-PGA and Dox in MCF7 ADR cells-shows that the pretargeted delivery of D-Dox-PGA resulted in a 2 to 4 fold increase in intracellular Dox concentration relative to treatment with free Dox. The mechanism of internalization of PPDCs is consistant with endocytosis. Enhanced drug delivery and intracellular retention following pretargeted delivery of PPDCs resulted in greater tumor cell toxicity in the current in vitro studies.

Research paper thumbnail of Smooth muscle cell proliferation index correlates with 111In-labeled antibody Z2D3 uptake in a transplant vasculopathy swine model

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2005

Transplant vasculopathy is a major cause of morbidity and mortality in heart transplantation. The... more Transplant vasculopathy is a major cause of morbidity and mortality in heart transplantation. The proliferation of coronary vascular smooth muscle cells is a hallmark of transplant vasculopathy. The goal of this study was to detect coronary vascular smooth muscle cell proliferation in a swine model by imaging regions of uptake of a monoclonal antibody (Z2D3) labeled with 111In. Coronary-to-right carotid artery transplantation was performed in 10 Yucatan minipigs with coronary arteries from farm pigs as donors. In 5 of these experiments, the right carotid artery was also grafted to the left carotid artery as a homograft. In 1 farm pig, the left and right carotid arteries were switched. After 44 +/- 22 days (mean +/- SE), animals were injected with 5-bromo-2-deoxyuridine (BrDU) and 111In-Z2D3 F(ab')2. Approximately 24 h later, the pigs underwent planar and SPECT imaging. After the imaging session, the pigs were sacrificed and the vessels were removed. Ex vivo autoradiography of al...

Research paper thumbnail of p-Nitrophenylcarbonyl-PEG-PE-liposomes: fast and simple attachment of specific ligands, including monoclonal antibodies, to distal ends of PEG chains via p-nitrophenylcarbonyl groups

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2001

We have attempted to simplify the procedure for coupling various ligands to distal ends of liposo... more We have attempted to simplify the procedure for coupling various ligands to distal ends of liposome-grafted polyethylene glycol (PEG) chains and to make it applicable for single-step binding of a large variety of a primary amino group-containing substances, including proteins and small molecules. With this in mind, we have introduced a new amphiphilic PEG derivative, p-nitrophenylcarbonyl-PEG-1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (pNP-PEG-DOPE), synthesized by reaction of DOPE with excess of bis(p-nitrophenylcarbonyl)-PEG in a chloroform/triethylamine mixture. pNP-PEG-DOPE readily incorporates into liposomes via its PE residue, and easily binds primary amino group-containing ligands via its waterexposed pNP groups, forming stable and non-toxic urethane (carbamate) bonds. The reaction between the pNP group and the ligand amino group proceeds easily and quantitatively at pH around 8.0, and remaining free pNP groups are promptly eliminated by spontaneous hydrolysis. Therefore, pNP-PEG-DOPE could serve as a very convenient tool for protein attachment to the distal ends of liposome-grafted PEG chains. To investigate the applicability of the suggested protocol for the preparation of long-circulating targeted liposomes, we have coupled several proteins, such as concanavalin A (ConA), wheat germ agglutinin (WGA), avidin, monoclonal antimyosin antibody 2G4 (mon2G4), and monoclonal antinucleosome antibody 2C5 (mon2C5) to PEG-liposomes via terminal pNP groups and studied whether the specific activity of these immobilized proteins is preserved. The method permits the binding of several dozens protein molecules per single 200 nm liposome. All bound proteins completely preserve their specific activity. Lectin-liposomes are agglutinated by the appropriate polyvalent substrates (mannan for ConA-liposomes and glycophorin for WGA-liposomes); avidin-liposomes specifically bind with biotin-agarose; antibody-liposomes demonstrate high specific binding to the substrate monolayer both in the direct binding assay and in ELISA. A comparison of the suggested method with the method of direct membrane incorporation was made. The effect of the concentration of liposome-grafted PEG on the preservation of specific protein activity in different coupling protocols was also investigated. It was also shown that pNP-PEG-DOPE-liposomes with and without attached ligands demonstrate increased stability in mouse serum.

Research paper thumbnail of Quo Vadis Radioimmune Imaging?—Reply

Journal of Nuclear Medicine, Aug 1, 1990

Sensitivitywas achieved with higher doses of antibody; * Sensitivity of 29% for 2.5 mg of antibod... more Sensitivitywas achieved with higher doses of antibody; * Sensitivity of 29% for 2.5 mg of antibody (n = 4) and 74% for 20 mg (n = 6);  § The false-positive rateinthisstudywas 50%. ft H = reference from Haipem et al. and 0 = reference from DeNardoand DeNardo. 3 multicenter trial, sensitivity was 94% for 202 patients with transmural infarction and 84% for 57 patients with non transmuralinfarction(6). In the caseofradioimmuno imaging for infection, the data are sparse. Similarly, imaging of throm bus alsogetsmixed reviews. Concerningthe important point raised about the number and affinity of binding sites for radioimmune imaging. Dr. Denardo states(7): â€oeIn the absenceof heterogeneousexpres sion ofthe antigen or obstacles to delivery of the antibody to the cell membrane antigenic sites, the iO'@to iO'@antibody molecules can be accumulated in 1 gram of cancer tissue.― This suggests that up to 250 @g of antibody (25% of the injecteddoseafteradministrationof 1.0mgof antibody)could be concentrated in a singlegram of tumor. These attractive assumptions, unfortunately, have not been borne out by din ical experience. In practice, lesions rarely concentrate more than 0.01%ofthe injecteddose. Weagreewiththe authorsthat the relativemassofantibody administered to a mouse or man is not the sole determinant for the different levelsof accumulation of radiolabeledanti body in tumors in these species.Imagingstudies performed following radioimmune therapy, where large amounts of pro tein and radioactivity are administered, rarely identify lesions

Research paper thumbnail of Acute myocardial infarct imaging with indium-111-labeled monoclonal antimyosin Fab

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1987

Indium-111 monoclonal antimyosin Fab scintigraphy was used to detect myocardial necrosis in 52 of... more Indium-111 monoclonal antimyosin Fab scintigraphy was used to detect myocardial necrosis in 52 of 54 patients (96.3%) with acute myocardial infarction. Infarcts were visualized when coronary arteries were persistently occluded (n = 10), became patent after thrombolysis (n = 33), or became patent after spontaneous reperfusion (n = 7). Posteroinferolateral visualizations were obtained in two patients with clinical and enzymatic evidence of infarction but normal electrocardiograms. Of the two patients in whom no infarcts were visualized, one had an anterior myocardial infarct. This patient underwent successful thrombolytic therapy, with attendant minimization of creatine kinase release. The other patient had a small, nonreperfused inferior myocardial infarct. Five patients with a history of remote infarction and acute necrosis showed antimyosin uptake only in regions concordant with the acute episodes of infarction, and radiolabeled antimyosin Fab localized in neither old infarcts nor ...

Research paper thumbnail of Monoclonal Antibodies Specific for Cardiac Myosin: In Vivo and in Vitro Diagnostic Tools in Myocardial Infarction

Research paper thumbnail of Relation of immediate and delayed thallium-201 distribution to localization of iodine-125 antimyosin antibody in acute experimental myocardial infarction

The American Journal of Cardiology, 1983

Thallium-201 (TI-201) distribution in acute experimental myocardial infarction (MI) (n = 18) was ... more Thallium-201 (TI-201) distribution in acute experimental myocardial infarction (MI) (n = 18) was compared with cardiac-specific antimyosin Fab (AM-Fab) uptake, a specific marker for myocardial necrosis. When antimyosin was injected 4 hours after ligation with TI-201 administered 23 hours 55 minutes later and measurement of myocardial distribution determined 5 minutes after intravenous administration of TI-201, (1) TI-201 distribution closely correlated with microsphere regional blood flow, and (2) an inverse exponential relation to iodine-125 (I-125) AM-Fab uptake was apparent. In another group of 4 animals, TI-201 and AM-Fab were administered intravenously 4 hours after MI, and 36 hours later myocardial distribution was measured. This delayed TI-201 distribution had a close inverse linear correlation with I-125 AM-Fab uptake. This inverse linear relation also was apparent in 28-hour-old MIs in dogs (n = 4) where collateral circulation had been established. TI-201 was administered intravenously at 27 hours after MI, and TI-201 distribution was determined 1 hour later. The present study demonstrated that whereas immediate TI-201 distribution is flow-limited, delayed TI-201 distribution is a marker of cell viability which, due to prolonged circulation time and redistribution, is not flow-limited.

Research paper thumbnail of Reagents and Methods for Bispecific Antibody-Based Binding of Target Molecules

Research paper thumbnail of Diagnosis of acute myocardial infarction by detection of circulating cardiac myosin light chains

The American Journal of Cardiology, 1984

Research paper thumbnail of Rapid noninvasive detection of experimental atherosclerotic lesions with novel 99m Tc-labeled diadenosine tetraphosphates

Proceedings of the National Academy of Sciences, 1998

The development of a noninvasive imaging procedure for identifying atherosclerotic lesions is ext... more The development of a noninvasive imaging procedure for identifying atherosclerotic lesions is extremely important for the clinical management of patients with coronary artery and peripheral vascular disease. Although numerous radiopharmaceuticals have been proposed for this purpose, none has demonstrated the diagnostic accuracy required to replace invasive angiography. In this report, we used the radiolabeled purine analog, 99m Tc diadenosine tetraphosphate (Ap 4 A; AppppA, P 1 , P 4 -di(adenosine-5′)-tetraphosphate) and its analogue 99m Tc AppCHClppA for imaging experimental atherosclerotic lesions in New Zealand White rabbits. Serial gamma camera images were obtained after intravenous injection of the radiolabeled dinucleotides. After acquiring the final images, the animals were sacrificed, ex vivo images of the aortas were recorded, and biodistribution was measured. 99m Tc-Ap 4 A and 99m Tc AppCHClppA accumulated rapidly in atherosclerotic abdominal aorta, and lesions were clearl...

Research paper thumbnail of Workload policy for Northeastern University

Research paper thumbnail of Immunoassay technique using multispecific molecules

Research paper thumbnail of Gamma imaging of atherosclerotic plaques

Current Cardiovascular Imaging Reports, 2009

ABSTRACT Noninvasive gamma imaging of atherosclerotic plaques targets various metabolic aspects o... more ABSTRACT Noninvasive gamma imaging of atherosclerotic plaques targets various metabolic aspects of atherogenesis. Vascular endothelial dysfunction or denudation resulting in the expression of adhesion molecules that attract inflammatory cells and increased vascular permeability has also been targeted. Enzymes and molecules associated with apoptosis of these inflammatory cells have provided additional targets, such as oxidized low-density lipoprotein, matrix metalloproteinases, and phosphatidylserine. In late atherosclerotic lesions, the lipid core as well as proliferating smooth muscle cells have been imaged successfully. Platelets and fibrin deposition may also be targeted to demonstrate thrombosis in plaque rupture or erosion. However, no unimodal approach can diagnose plaque vulnerability. It will require multi-modal, multitasking approaches for molecular diagnostic prediction of plaque vulnerability and impending rupture. Existing experimental and clinical gamma imaging applications in atherosclerotic lesion imaging are reviewed. Improvement by signal amplification to image small lesion and the concept of multimodal applications are introduced.

Research paper thumbnail of Monoclonal Antibody to Cardiac Myosin: Imaging of Experimental Myocardial Infarction

Hybridoma, 1984

Monoclonal antibody R11D10 to human cardiac myosin, which also cross-reacted with canine cardiac ... more Monoclonal antibody R11D10 to human cardiac myosin, which also cross-reacted with canine cardiac myosin, was used to demonstrate in vivo localization and visualization by gamma scintigraphy of experimental myocardial infarction. R111)10 Fab with a Ka of 5 x 108 M_1 was labeled with technetium-99m ("mTc) by the dithionite reduction method of technetium pertechnetate, via a bifunctional chelating agent, diethylene triamine pentaacetic acid (DTPA). Uptake of 99mTc R11D10 Fab in the infarct can be visualized as early as 2 h after intravenous administration. Comparison of Rl 11)10 uptake to thallium-201, an analogue of potassium which is sequestered by normal myocardium, showed an inverse relation (r =-0.75,-0.87,-0.89), similar to that obtained with l2sI labeled polyclonal antimyosin Fab. Ratios of Rl 11)10 Fab in the infarct to normal myocardium were as high as 30:1 where access of antibody to antigen was not blood flow limited. However, with severe blood-flow restriction, the ratios were lower at about 10:1. Despite the theoretical limitation of a single epitope per myosin molecule available for binding by Rl II) 10 Fab, the immense excess of myosin in the infarcted myocardium allowed adequate concentration of radiolabeled R11D10 for visualization of the infarct by external gamma scintiscanning.

Research paper thumbnail of Targeting the Pathological Myocardium

Biomedical Aspects of Drug Targeting, 2002

The rationale for targeting the pathological myocardium is to enable development of better diagno... more The rationale for targeting the pathological myocardium is to enable development of better diagnostic modalities or to enhance therapeutic interventions. Since the heart is an end-differentiated organ that has no substantial regenerative properties, any injury to the heart could potentially lead to high morbidity and mortality. The causes of myocardial injury are varied. Acute myocardial infarction results in oncotic myocardial cell death, whereas cardiomyopathies are now believed to be associated primarily with apoptotic myocardial cell death. If these myocardial disorders can be targeted specifically for early diagnosis, then morbidity and mortality may be reduced and novel therapeutic interventions may result in decreasing the injury to the heart. This chapter will focus primarily on targeting the oncotic myocardium. Targeting the apoptotic myocardium will not be considered in detail, but an introduction to the latest advances will be provided.

Research paper thumbnail of Targeting Atherosclerotic Plaques

Biomedical Aspects of Drug Targeting, 2002

Clinical imaging of atherosclerotic plaques is based on anatomical demonstration of the narrowing... more Clinical imaging of atherosclerotic plaques is based on anatomical demonstration of the narrowing of the involved artery (1). Angioscopy (2) and intravascular ultrasound (3) can demonstrate the precise location of the lesions, the extent of luminal narrowing and plaque thickening. However, both methods are invasive and cannot provide the composition or the metabolic status of the atherosclerotic lesion (4). Plaques rich in macrophages and foam cells may denote high risk of plaque rapture (5) whereas fibrous plaques may denote slowly emergent lesions. Lesions rich in actively proliferating smooth muscle cells may be an indication of accelerated luminal diameter reduction (6). Other targets that might have potential applications may be associated with neoantigens that are expressed due to microvascular injury inherent in atherogenesis. Therefore, targeting macrophage, foam cell hyper-accumulation or hyperactivity intravascularly, neoexpression or hyperexpression of various vascular adhesion molecules, or the metabolites that may be incorporated into the cellular components of the atherosclerotic lesions may provide novel and specific diagnostic and therapeutic applications.

Research paper thumbnail of Radionuclide Imaging of the Synthetic Smooth Muscle Cell Phenotype in Experimental Atherosclerotic Lesions

Trends in Cardiovascular Medicine, 1996

Hypertrophic stimufi induce tmnsforming growth factor-beta 1 expressionin rat ventricular myocyte... more Hypertrophic stimufi induce tmnsforming growth factor-beta 1 expressionin rat ventricular myocytes. J Clin Invest 94:147& 1476. ThaikCM, CafderoneA, Takahashi N, Cheng,et af.: 1995.Effects of inflammatorycytokines on growth and growth factor expressionin cardiac myocytesand fibroblasts[abst]. Cir-culation92:1-569.

Research paper thumbnail of Palmitoyl Ascorbate Liposomes and Free Ascorbic Acid: Comparison of Anticancer Therapeutic Effects Upon Parenteral Administration

Pharmaceutical Research, 2011

To evaluate and compare anticancer therapeutic effect of palmitoyl ascorbate liposomes (PAL) and ... more To evaluate and compare anticancer therapeutic effect of palmitoyl ascorbate liposomes (PAL) and free ascorbic acid (AA). Liposomes incorporating palmitoyl ascorbate (PA) were prepared and evaluated for PA content by HPLC. To elucidate mechanism of action of cell death in vitro, effect of various H(2)O(2) scavengers and metal chelators on PA-mediated cytotoxicity was studied. Effect of various combinations of PAL and free AA on in vitro cytotoxicity was evaluated on 4T1 cells. In vivo, PAL formulation was modified with polyethylene glycol; effect of PEGylation on in vitro cytotoxicity was evaluated. Biodistribution of PEG-PAL formulation was investigated in female Balb/c mice bearing murine mammary carcinoma (4T1 cells). In vivo anticancer activity of PEG-PAL (PEG-PAL equivalent to 20 mg/kg of PA injected intravenously on alternate days) was compared with free AA therapy in same model. PEG-PAL treatment was significantly more effective than free AA treatment in slowing tumor growth. Nanoparticle formulations incorporating PA can kill cancer cells in vitro. The mechanism of PA cytotoxicity is based on production of extracellular reactive oxygen species and involves intracellular transition metals.

Research paper thumbnail of Targeting very small model lesions pretargeted with bispecific antibody with 99mTc-labeled high-specific radioactivity polymers

Nuclear Medicine Communications, 2010

Background Two-step targeting with bispecific antibody and 99m Tc-labeled high-specific radioacti... more Background Two-step targeting with bispecific antibody and 99m Tc-labeled high-specific radioactivity polymers was used for molecular imaging of two very small model lesions in rats. Methods and results Sprague-Dawley rats (group I) were injected with surrogate antigen-coated beads (SA beads) in the right hind leg or unmodified beads in the contralateral hind leg. In group II, femoral artery de-endothelialization was induced in the left hind leg and sham operation was performed in the contralateral hind leg. Bispecific antibody Z 2 D 3 F(ab 0) 2-anti-DTPA F(ab 0) 2 was injected intravenously 24 h after SAB injection or 1 week after endothelial denudation. 99m Tc-labeled polymers were injected intravenously 24 h later and c-images obtained at 2 and 24 h in group I or approximately 2.5 h in group II. Lesions were visualized by 2 h. In group I, SA beads-specific uptake in muscles was significantly greater than with unmodified beads (P < 0.015). In group II, lesions were visualized by 2.5 h after radiopolymer injection with uptake activity 2.1 ± 0.6 times greater than in the contralateral side from in-vivo images (P < 0.004) and 1.8 ± 0.7 times by c-scintillation counting (P < 0.04). Conclusion Pretargeting with Z 2 D 3 bispecific antibody for the localization of radiolabeled polymers enabled successful in-vivo c-imaging of very small lesions in two rat models of extravascular and intravascular targets. Biodistribution data confirmed that pretargeting with bispecific antibody enabled targeted visualization of two different very small model lesions by in-vivo c-imaging. Nucl Med Commun 31:320-327

Research paper thumbnail of Apoptosis in Myocytes in End-Stage Heart Failure

New England Journal of Medicine, 1996

Background Heart failure can result from a variety of causes, including ischemic, hypertensive, t... more Background Heart failure can result from a variety of causes, including ischemic, hypertensive, toxic, and inflammatory heart disease. However, the cellular mechanisms responsible for the progressive deterioration of myocardial function observed in heart failure remain unclear and may result from apoptosis (programmed cell death). Methods We examined seven explanted hearts obtained during cardiac transplantation for evidence of apoptosis. All seven patients had severe chronic heart failure: four had idiopathic dilated cardiomyopathy, and three had ischemic cardiomyopathy. DNA fragmentation (an indicator of apoptosis) was identified histochemically by in situ end-labeling as well as by agarose-gel electrophoresis of end-labeled DNA. Myocardial tissues obtained from four patients who had had a myocardial infarction one to two days previously were used as positive controls, and heart tissues obtained from four persons who died in motor vehicle accidents were used as negative controls for the end-labeling studies. Results Hearts from all four patients with idiopathic dilated cardiomyopathy and from one of the three patients with ischemic cardiomyopathy had histochemical evidence of DNA fragmentation. All four myocardial samples from patients with dilated cardiomyopathy also demonstrated DNA laddering, a characteristic of apoptosis, whereas this was not seen in any of the samples from patients with ischemic cardiomyopathy. Histologic evidence of apoptosis was also observed in the central necrotic zone of acute myocardial infarcts, but not in myocardium remote from the infarcted zone. Rare isolated apoptotic myocytes were seen in the myocardium from the four persons who died in motor vehicle accidents. Conclusions Loss of myocytes due to apoptosis occurs in patients with end-stage cardiomyopathy and may contribute to progressive myocardial dysfunction.