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105 results on '"Kulkarni, Padmakar V."'

3. UTSW small animal positron emission imager

Author

Tsyganov, Edward N., Anderson, Jon, Arbique, Gary, Constantinescu, Anca, Jennewein, Marc, Kulkarni, Padmakar V., Mason, Ralph P., McColl, Roderick W., Oz, Orhan K., Parkey, Robert W., Richer, Edmond, Rosch, Frank, Seliounine, Serguei Y., Slavine, Nikolai V., Srivastava, Suresh C., Thorpe, Philip E., Zinchenko, Alexander I., and Antich, Peter P.

Subjects
Medical imaging equipment -- Design and construction, Photoelectric multipliers -- Design and construction, PET imaging -- Methods, Animals -- Medical examination, Business, Electronics, Electronics and electrical industries
Abstract

A Small Animal Imager (SAI) for PET has been designed, built, tested in phantoms, and applied to investigations in mice and rats. The device uses principles based on [gamma]-ray induced scintillation in crossed fiber optic detectors connected to Position Sensitive Photomultiplier Tubes (PSPMT). Each detector consists of an epoxied stack of 28 layers of 135 round 1 mm BCF-10 scintillating plastic fibers. The overlap region forms a 13.5 x 13.5 x 2.8 [cm.sup.3] detector volume. Scintillating light from the fibers is detected by two (X and Y directions) Hamamatsu R-2486 PSPMTs with 16 anode wires in each of two orthogonal directions. A centroid-finding algorithm gives the position of a light cluster on the face (photocathode) of a PSPMT. The accuracy of the reconstruction of an interaction position is essentially independent of light cluster position. This translates to a nearly isotropic photon response for the entire detector. The system has been used to test several 3D image reconstruction algorithms, software modifications, and improvements. The sensitivity (~12.6 cps/kBq at 9 cm inner diameter) and sub-millimeter spatial resolution (better than 1 mm in phantoms) obtained with an iterative algorithm incorporating system modeling make the SAI a relatively inexpensive high performance animal imager. The SAI is currently being used for imaging experiments in mice and rats. Index Terms--Antibodies, arsenic, FDG, image reconstruction, positron emission tomography, small animal imaging.

Published
2006

13. A New F-18 Labeled PET Agent For Imaging Alzheimer’s Plaques

Author

Kulkarni, Padmakar V., primary, Vasdev, Neil, additional, Hao, Guiyang, additional, Arora, Veera, additional, Long, Michael, additional, Slavine, Nikolai, additional, Chiguru, Srinivas, additional, Qu, Bao Xi, additional, Sun, Xiankai, additional, Bennett, Michael, additional, Antich, Peter P., additional, Bonte, Frederick J., additional, McDaniel, Floyd D., additional, and Doyle, Barney L., additional

Published
2011
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18. 4-Bromo-8-methoxyquinoline

Author

Vasdev, Neil, primary, Kulkarni, Padmakar V., additional, Wilson, Alan A., additional, Houle, Sylvain, additional, and Lough, Alan J., additional

Published
2008
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24. Reconstruction Algorithm with Resolution Deconvolution in a Small-Animal PET Imager.

Author

Kupinski, Matthew A., Barrett, Harrison H., Tsyganov, Edward N., Zinchenko, Alexander I., Slavine, Nikolai V., Antich, Pietro P., Seliounine, Serguei Y., Oz, Orhan K., Kulkarni, Padmakar V., Lewis, Matthew A., Mason, Ralph P., and Parkey, Robert W.

Abstract

A small-animal PET imaging device has been developed at the University of Texas Southwestern Medical Center at Dallas using scintillating 1-mm round BCF10 fibers and small admixture of CsF microcrystals between the fibers [Antich, 1990, Atac, 1991, Fernando, 1996 ]. The fiber core is polystyrene (C 8 H 8 )n doped with butyl-PBD and dPOPOP. The fibers are clad in a non-scintillating lucite cladding. The scintillation mechanism can be either from the excitation of π electrons in the butyl-PBD benzene ring in the fiber or from excitation within the microcrystals. In both cases, the emitted light is compatible with the optimal spectral response of standard photomultiplier cathodes. For a 511 keV photon in plastic,the photo-absorption is small, and Compton scatter interactions are dominant. The scattered electrons give up their energy well within a fiber diameter, but wave-shifting produces light in proximal fibers. The current imager uses the 2-fold coincident detection of a single event in 2 orthogonal fibers of 1-mm diameter to detect the location and the energy transferred at a point within the detector. Two sets of fibers each 60 cm in length and 1 mm in diameter were used to construct two alternating, mutually orthogonal sets of 14 planar arrays of 135 fibers each. In this detector, the planar fiber arrays are arranged along two alternating mutually orthogonal (X and Y)axes and are stacked along a third (Z). Scintillating light from the fibers is detected by two (X and Y directions) Hamamatsu R-2486 Position Sensitive Photomultiplier Tubes (PSPMT). A single-ended readout scheme is used, where the X,Z and Y,Z interaction positions in a detector are determined from coincident detection in the two PSPMT. The precision of the detection of the interaction point depends upon PSPMT performance and software filters. [ABSTRACT FROM AUTHOR]

Published
2005
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27. Influence of Cardiopulmonary Bypass on Platelet and Neutrophil Accumulations in Internal Organs

Author

BHUJLE, ROHAN, primary, LI, JUN, additional, SHASTRI, PARAG, additional, GAFFKE, JOHN N., additional, CLIFT, JAMES E., additional, YE, YUN-WEI, additional, DOLLAR, MICHAEL L., additional, CHING, PETER, additional, CHAO, ROBERT, additional, CONSTANTINESCU, ANCA, additional, KULKARNI, PADMAKAR V., additional, CHENG, QIN-CHANG, additional, WIANS, FRANK, additional, JESSEN, MICHAEL E., additional, and EBERHART, ROBERT C., additional

Published
1997
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28. Platelet and Neutrophil Distributions in Pump Oxygenator Circuits

Author

SLY, M. KURT, primary, PRAGER, MORTON D., additional, LI, JUN, additional, HARRIS, FREDERICK B., additional, SHASTRI, PARAG, additional, BHUJLE, ROHAN, additional, CHAO, ROBERT, additional, KULKARNI, PADMAKAR V., additional, CONSTANTINESCU, ANCA, additional, JESSEN, MICHAEL E., additional, and EBERHART, ROBERT C., additional

Published
1996
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31. Controlled release of therapeutics using interpenetrating polymeric networks

Author

Aminabhavi, Tejraj M, Nadagouda, Mallikarjuna N, More, Uttam A, Joshi, Shrinivas D, Kulkarni, Venkatrao H, Noolvi, Malleshappa N, and Kulkarni, Padmakar V

Abstract

Introduction:The ever-increasing developments in pharmaceutical formulations have led to the widespread use of biodegradable polymers in various forms and configurations. In particular, interpenetrating network (IPN) and semi-IPN polymer structures that are capable of releasing drugs in a controlled manner have gained much wider importance in recent years.Areas covered:Recently, IPNs and semi-IPNs have emerged as innovative materials of choice in controlled release (CR) of drugs as the release from these systems depends on pH of the media and temperature in addition to the nature of the system. These networks can be prepared as smart hydrogels following chemical or physical crosslinking methods to show remarkable drug release patterns compared to single polymer systems.Expert opinion:A large number of IPNs and semi-IPNs have been reported in the literature. The present review is focused on the preparation methods and their CR properties with reference to anticancer, anti-asthmatic, antibiotic, anti-inflammatory, anti-tuberculosis and antihypertensive drugs, as majority of these drugs have been reported to be the ideal choices for using IPNs and semi-IPNs.

Published
2015
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32. Imaging of folate receptors with I-125 labeled folate using small animal imaging system built with plastic scintillating optical fibers

Author

Kulkarni, Padmakar V., primary, Antich, Peter P., additional, Constantinescu, Anca, additional, Anderson, Jon A., additional, Fernando, Johann L., additional, Prior, John O., additional, Nguyen, Ton, additional, Parkey, Robert W., additional, Weitman, S. D., additional, Kamen, B. A., additional, Chaney, Roy C., additional, and Fenyves, Ervin J., additional

Published
1994
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40. Quinoline- n-butylcyanoacrylate-based nanoparticles for brain targeting for the diagnosis of Alzheimer's disease.

Author

Kulkarni, Padmakar V., Roney, Celeste A., Antich, Peter P., Bonte, Frederick J., Raghu, Anjanapura V., and Aminabhavi, Tejraj M.

Abstract

A survey of research activity on nanoparticles (NPs) based on polymeric devices that could cross the blood-brain barrier (BBB) is given along with the presentation of our own data on the development of NPs of n-butyl-2-cyanoacrylate (BCA) for brain delivery to aid the early diagnosis of Alzeimer's disease (AD), a neurodegenerative disorder of the elderly people, the most prevalent form of dementia. Typical data are presented on in vivo detection of amyloid peptides (Aβ) (amyloid plaques) that are used as targets for developing the biological markers for the diagnosis of AD. In order to develop efficient in vivo probes, polymeric n-butyl-2-cyanoacrylate (PBCA) NPs have been prepared and encapsulated with the radio-labeled amyloid affinity drug I-clioquinol (CQ, 5-chloro-7-iodo-8-hydroxyquinoline) to improve the transport to brain and amyloid plaque retention of I-CQ using the NPs of PBCA. The I-CQ discriminately binds to the AD post-mortem brain tissue homogenates versus control. I-CQ-PBCA NPs labeled the Aβ plaques from the AD human post-mortem frontal cortical sections on paraffin-fixed slides. Storage phosphor imaging verified preferential uptake by AD brain sections compared to cortical control sections. The I-CQ-PBCA NPs crossed the BBB in wild type mouse, giving an increased brain uptake measured in terms of % ID/g i.e., injected dose compared to I-CQ. Brain retention of I-CQ-PBCA NPs was significantly increased in the AD transgenic mice (APP/PS1) and in mice injected with aggregated Aβ42 peptide versus age-matched wild type controls. The results of this study are verified by in vivo storage phosphor imaging and validated by histopathological staining of plaques and select metal ions, viz. Fe and Cu. The I-CQ-PBCA NPs had more efficient brain entry and rapid clearance in normal mice and enhanced the retention in AD mouse brain demonstrating the ideal in vivo imaging characteristics. The I-CQ-PBCA NPs exhibited specificity for Aβ plaques both in vitro and in vivo. This combination offered radio-iodinated CQ-PBCA NPs as the promising delivery vehicle for in vivo single photon emission tomography (SPECT) (I) or PET (I) amyloid imaging agent. The importance of the topic in relation to brain delivery and other similar type of work published in this area are covered to highlight the importance of this research to medical disciplines. WIREs Nanomed Nanobiotechnol 2010 2 35-47 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

Published
2010
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47. Simultaneous intracellular and extracelular pHmeasurement in the heart by 19F NMR of 6‐fluoropyridoxol

Author

Hunjan, Sandeep, Mason, Ralph P., Mehta, Vimal D., Kulkarni, Padmakar V., Aravind, Subramanian, Arora, Veeva, and Antich, Peter P.

Abstract

6‐Fluoropyridoxol (6‐FPOL) was evaluated as a simultaneous indicator of intracellular and extracellular pH and, hence, pH gradient in perfused rat hearts. After infusion, 19F NMR spectra rapidly showed two well‐resolved peaks assigned to the intracellular and extracellular compartments, and pH was calculated on the basis of chemical shift with respect to asodium trifluoroacetate standard. To demonstrate use of this molecule, dynamic changes in myocardial pH were assessed with a time resolution of 2 min during respiratory and metabolic alkalosis or acidosis and ischemia. For a typical heart, intracellular pH (pHi) = 7.14 ± 0.01 and extracellular pH (pHe) = 7.52 ± 0.02. In response to metabolic alkalosis, pHi remained relatively constant and the pH gradient increased. In contrast, respiratory challenge caused a significant increase in pHi. Independent measurements using pH electrodes and 31P NMR confirmed validity of the 19F NMR results.

Published
1998
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48. 6-Fluoropyridoxol: A novel probe of cellular pH using 19F NMR spectroscopy

Author

Mehta, Vimal D., Kulkarni, Padmakar V., Mason, Ralph P., Constantinescu, Anca, Aravind, Sivasubramanian, Goomer, Naresh, and Antich, Peter P.

Abstract

6-Fluoropyridoxol was evaluated as an intracellular pH indicator. This molecule exhibits exceptional sensitivity to changes in pH (∼ 10 ppm acid/base shift) and a p Ka∼8.2 appropriate for physiological investigations. Using 19F NMR spectroscopy we determined both intra- and extracellular pH in whole blood and confirmed the measurements using traditional techniques: ion-electrodes and 31P NMR spectroscopy.

Published
1994
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49. Development of novel 19F NMR pH indicators: synthesis and evaluation of a series of fluorinated vitamin B6analogues

Author

He, Sha, Mason, Ralph P., Hunjan, Sandeep, Mehta, Vimal D., Arora, Veera, Katipally, Revathi, Kulkarni, Padmakar V., and Antich, Peter P.

Abstract

We have synthesized a series of novel fluorinated vitamin B6analogues (6-fluoropyridoxol derivatives) as potential 19F NMR pH indicators for use in vivo. Modifications included addition of aldehyde, carboxyl or aminomethyl groups at the 4- or 5-ring position, and examination of a trifluoromethyl moiety as an internal chemical shift standard. The variation in chemical shift with respect to acid–base titration showed pKavalues in the range 7.05–9.5 with a chemical shift sensitivity in the range 7.4–12ppm. Several of the molecules readily cross cell membranes providing estimates of both intra- and extra-cellular pH in whole blood. 6-Fluoropyridoxamine (6-FPAM) exhibits a pKa=7.05, which is closer to normal physiological pH than the parent molecule 6-fluoropyridoxol (6-FPOL) (pKa=8.2), and should thus, be useful for precise and accurate measurements of pH in vivo. Enhanced spectral resolution for 6-FPAM over 6-FPOL is demonstrated in whole blood and the perfused rat heart.

Published
1998
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