Browsing by Author "Saraswathy, A"

Now showing 1 - 20 of 29
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    Asialoglycoprotein receptor targeted optical and magnetic resonance imaging and therapy of liver fbrosis using pullulan stabilized multi-functional iron oxide nanoprobe
    (Scientific Reports., 2021-09) Saraswathy, A; Nazeer, SS; Nimi, N; Hema, S; Parvathy, RS; Jibin, K; Victor, M; Fernandez, FB; Sabareeswaran, A; Shenoy, SJ; Harikrishna Varma, PR; Jayasre, RS
    Early diagnosis and therapy of liver fibrosis is of utmost importance, especially considering the increased incidence of alcoholic and non-alcoholic liver syndromes. In this work, a systematic study is reported to develop a dual function and biocompatible nanoprobe for liver specific diagnostic and therapeutic applications. A polysaccharide polymer, pullulan stabilized iron oxide nanoparticle (P-SPIONs) enabled high liver specificity via asialogycoprotein receptor mediation. Longitudinal and transverse magnetic relaxation rates of 2.15 and 146.91 mM−1 s−1 respectively and a size of 12 nm, confirmed the T2 weighted magnetic resonance imaging (MRI) efficacy of P-SPIONs. A current of 400A on 5 mg/ml of P-SPIONs raised the temperature above 50 °C, to facilitate effective hyperthermia. Finally, a NIR dye conjugation facilitated targeted dual imaging in liver fibrosis models, in vivo, with favourable histopathological results and recommends its use in early stage diagnosis using MRI and optical imaging, and subsequent therapy using hyperthermia.
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    Catechin tuned magnetism of Gd-doped orthovanadate through morphology as T-1-T-2 MRI contrast agents
    (SCIENTIFIC REPORTS, 2016) Vairapperumal, T; Saraswathy, A; Ramapurath, JS; Janardhanan, SK; Unni, NB
    Tetragonal (t)-LaVO4 has turned out to be a potential host for luminescent materials. Synthesis of t-LaVO4 till date has been based on chelating effect of EDTA making it not ideal for bioimaging applications. An alternative was proposed by us through the use of catechin. In recent times there is interest for new MRI contrast agents that can through appropriate doping function both as MRI contrast and optical/upconversion materials. It is generally believed that under appropriate doping, t-LaVO4 would be a better upconversion material than monoclinic (m)-LaVO4. Based on these postulations, this work explores the use of gadolinium doped t-LaVO4 as an MRI contrast agent. From literature, gadolinium oxide is a good T-1 contrast agent. Through this work, using catechin as a template for the synthesis of Gd doped t-LaVO4, we demonstrate the possible use as a T-1 contrast agent. Interestingly, as the catechin concentration changes, morphology changes from nanorods to square nanoplates and spheres. In this process, a switch from T-1 to T-2 contrast agent was also observed. Under optimal concentration of catechin, with a rod shaped Gd doped t-LaVO4 an r(2)/r(1) value of 21.30 was observed. Similarly, with a spherical shape had an r(2)/r(1) value of 1.48 was observed.
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    Catechin tuned magnetism of Gd-doped orthovanadate through morphology as T1-T2 MRI contrast agents
    (Scientific Reports, 2016-10) Vairapperumal, T; Saraswathy, A; Ramapurath, S Jayasree; Janardhanan, SK; Unni, NB
    Tetragonal (t)-LaVO4 has turned out to be a potential host for luminescent materials. Synthesis of t-LaVO4 till date has been based on chelating effect of EDTA making it not ideal for bioimaging applications. An alternative was proposed by us through the use of catechin. In recent times there is interest for new MRI contrast agents that can through appropriate doping function both as MRI contrast and optical/upconversion materials. It is generally believed that under appropriate doping, t-LaVO4 would be a better upconversion material than monoclinic (m)-LaVO4. Based on these postulations, this work explores the use of gadolinium doped t-LaVO4 as an MRI contrast agent. From literature, gadolinium oxide is a good T1 contrast agent. Through this work, using catechin as a template for the synthesis of Gd doped t-LaVO4, we demonstrate the possible use as a T1 contrast agent. Interestingly, as the catechin concentration changes, morphology changes from nanorods to square nanoplates and spheres. In this process, a switch from T1 to T2 contrast agent was also observed. Under optimal concentration of catechin, with a rod shaped Gd doped t-LaVO4 an r2/r1 value of 21.30 was observed. Similarly, with a spherical shape had an r2/r1 value of 1.48 was observed.
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    Citrate coated iron oxide nanoparticles with enhanced relaxivity for in vivo magnetic resonance imaging of liver fibrosis.
    (Colloids and surfaces B: Biointerfaces., 2014-03) Saraswathy, A; Shaiju, S. Nazeer; Madhumol, Jeevan; N. Nimi; A.Sabareeswaran; V.S.Harikrishnan; P.R. Harikrishna Varma; R.S. Jayasree
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    Diagnostic utility of immunohistochemical techniques in intramedullary Schwann-cell tumours.
    (Indian journal of pathology & microbiology, 1993)
    Histopathologic features in two intramedullary schwann-cell tumours, closely resembled with those of fibrillary astrocytoma and could not be differentiated from each other by the conventional histochemical stains. However application of tumour markers-Glial fibrillary acidic protein (GFAP) and S-100 protein were found to be useful in differentiating these two tumours and thus helped in making an accurate histopathological diagnosis in these two patients.
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    Diffuse form of primary leptomeningeal gliomatosis--a case report.
    (Indian journal of pathology & microbiology, 1994)
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    Disseminated intra-cerebral microabscesses: a clinico-pathologic study.
    (Indian journal of pathology & microbiology, 1994)
    In this retrospective study, clinical and neuropathological features were analysed in eight patients with disseminated intracerebral microabscesses. All the patients presented with clinical features, suggestive of an encephalopathic process of an acute onset. Neuroradiological and laboratory investigations were not helpful in establishing the diagnosis in any patient during their hospital stay. All the eight patients died in the hospital and at autopsy disseminated intracerebral microabscesses were the most striking feature. In two patients hyphae of Candida albicans were demonstrated within the microabscesses. Gram negative bacilli in two patients and gram positive and gram positive cocci in one patient were demonstrated in the microabscesses. Disseminated intra-cerebral microabscesses are usually an unrecognised manifestation of central nervous system infections and should be considered in the differential diagnosis of patients with encephalopathy of unknown aetiology.
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    Effect of myosin B on guinea pig muscles--light microscopic and immunological aspects.
    (Indian journal of experimental biology, 1994)
    Experimental myositis was induced in guinea pigs by multiple inoculations with Myosin B fraction of the rabbit skeletal muscle. Quantitative histopathological features were studied and they include necrosis, central nucleation, inflammatory cellular reaction. Besides myositis, features of myocarditis were evident in 40% animals. Circulating immune complexes (CICs) in the sera of experimental animals were isolated by a polyethylene glycol (PEG) precipitation method. Presence of antimyosin B antibody in the immune complexes was characterised by an enzyme-linked immunosorbent assay. The role of circulating immune complexes in pathogenesis of experimental myositis and human polymyositis have been emphasised.
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    Fluorescence spectroscopy as a highly potential single-entity tool to identify chromophores and fluorophores: study on neoplastic human brain lesions
    (JOURNAL OF BIOMEDICAL OPTICS, 2013) Nazeer, SS; Saraswathy, A; Gupta, AK; Jayasree, RS
    Fluorescence and diffuse reflectance spectroscopy are powerful tools to differentiate normal and malignant tissue based on the emissions from endogenous fluorophores and diffuse reflection of absorbers such as hemoglobin. However, separate analytical methods are used for the identification of fluorophores and hemoglobin. The estimation of fluorophores and hemoglobin simultaneously using a single technique of autofluorescence spectroscopy is reported, and its diagnostic potential on clinical tissue samples is potentially exploited. Surgically removed brain tissues from patients that are later identified pathologically as astrocytoma, glioma, meningioma, and schwannoma are studied. The emissions from prominent fluorophores collagen, flavin adenine dinucleotide, phospholipids, and porphyrin are analyzed at 320 and 410 nm excitations. The hemoglobin concentration is also calculated from the ratio of fluorescence emissions at 500 and 570 nm. A better classification of normal and tumor tissues is yielded for 410 nm excitation compared to 320 nm when diagnostic algorithm based on linear discriminant analysis is used. The potential of fluorescence spectroscopy as a single entity to evaluate the prominent fluorophores as well as the hemoglobin concentration within normal and tumor brain tissues is emphasized. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)
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    Fluorescence spectroscopy as an efficient tool for staging the degree of liver fibrosis: an in vivo comparison with MRI
    (Sci Rep. 2018, 2018-07) Nazeer, SS; Saraswathy, A; Shenoy, SJ; Jayasree, RS
    The study utilizes autofuorescence spectroscopy (AFS) along with multivariate spectral analysis for diferentiating various stages of hepatic fbrosis. AFS has recently emerged as an efcient tool for evaluating the variations in diferent endogenous furophores. In this study, the potential of AFS for diferentiating the stages of liver fbrosis is assessed and compared with the results of enzyme evaluation, histopathology and the most advanced diagnostic tool, MRI. Using a fber optic probe, the emission profle of the furophores such as favin adenine dinucleotide (FAD), lipofuscin-like lipopigments (lipopigments), porphyrins and the variation in the total hemoglobin concentration are evaluated in vivo on liver fbrosis induced animal models adopting a minimally invasive technique. Signifcant diference (p<0.05) in the level of these biomarkers was observed between diferent stages of liver fbrosis. Normal hepatic tissue could be distinguished from mild and moderate hepatic fbrosis with a sensitivity of 95 to 100% and specifcity of 90 to 100% using multivariate spectral analysis. The results are favourable to consider this technique as a potential tool for diagnosing liver fbrosis at an early stage, which is monumental as it otherwise can lead to cirrhosis and liver failure.
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    Fluorescence spectroscopy to discriminate neoplastic human brain lesions: a study using the spectral intensity ratio and multivariate linear discriminant analysis
    (LASER PHYSICS, 2014) Nazeer, SS; Saraswathy, A; Gupta, AK; Jayasree, RS
    Fluorescence spectroscopy is an emerging tool used to differentiate normal and malignant tissue based on the emission spectral profile from endogenous fluorophores. The goal of this study is to estimate the concentration of fluorophores using autofluorescence spectroscopy and try to utilize its diagnostic potential on samples of clinical importance. Brain tumor tissues from patients who received craniotomy for the removal of astrocytoma, glioma, meningioma and schwannoma were utilized in this study. Fluorescence emissions of the formalin fixed samples were recorded at excitation wavelengths of 320 and 410 nm. The emission characteristics of fluorophores such as collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), phospholipids and porphyrins of tumor tissue and adjacent normal tissue were elicited. Exact tissue classification was carried out using the spectral intensity ratio (SIR) and multivariate principal component analysis-linear discriminant analysis (PCA-LDA). The diagnostic algorithm based on PCA-LDA provided better classification efficiency than SIR. Moreover, the spectral data based on an excitation wavelength of 410 nm are found to be more efficient in the classification than 320 nm excitation, using PCA-LDA. Better efficacy of PCA-LDA in tissue classification was further confirmed by the receiver operator characteristic (ROC) curve method. The results of this study establish the feasibility of using fluorescence spectroscopy based real time tools for the discrimination of brain tumors from the adjacent normal tissue during craniotomies, which at present faces a huge challenge.
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    Fluorescence spectroscopy to discriminate neoplastic human brain lesions: a study using the spectral intensity ratio and multivariate linear discriminant analysis.
    (Laser Physics., 2014-01) Nazeer, SS; Saraswathy, A; Gupta, AK; Jayasree, RS
    Fluorescence spectroscopy is an emerging tool used to differentiate normal and malignant tissue based on the emission spectral profile from endogenous fluorophores. The goal of this study is to estimate the concentration of fluorophores using autofluorescence spectroscopy and try to utilize its diagnostic potential on samples of clinical importance. Brain tumor tissues from patients who received craniotomy for the removal of astrocytoma, glioma, meningioma and schwannoma were utilized in this study. Fluorescence emissions of the formalin fixed samples were recorded at excitation wavelengths of 320 and 410 nm. The emission characteristics of fluorophores such as collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), phospholipids and porphyrins of tumor tissue and adjacent normal tissue were elicited. Exact tissue classification was carried out using the spectral intensity ratio (SIR) and multivariate principal component analysis–linear discriminant analysis (PCA–LDA). The diagnostic algorithm based on PCA–LDA provided better classification efficiency than SIR. Moreover, the spectral data based on an excitation wavelength of 410 nm are found to be more efficient in the classification than 320 nm excitation, using PCA–LDA. Better efficacy of PCA–LDA in tissue classification was further confirmed by the receiver operator characteristic (ROC) curve method. The results of this study establish the feasibility of using fluorescence spectroscopy based real time tools for the discrimination of brain tumors from the adjacent normal tissue during craniotomies, which at present faces a huge challenge.
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    Fluorescent carbon dots tailored iron oxide nano hybrid system for in vivo optical imaging of liver fibrosis
    (Methods and Applications in Fluorescence, 2023-03) Nazeer, SS; Saraswathy, A; Nimi, N; Sarathkumar, E; Resmi, AN; Shenoy, SJ; Jayasree, RS
    Hybrid nanoparticles are innovative invention of last decade designed to overcome limitations of single-component nanoparticles by introducing multiple functionalities through combining two or more different nanoparticles. In this study, we are reporting development of magneto-fluorescent hybrid nanoparticles by combining iron oxide and carbon nanoparticles to enablein vivofluorescence imaging which also has all the required characteristic properties to use as Magnetic Resonance Imaging (MRI) contrast agent. In order to achieve dual-functional imaging, alginate and pullulan coated super paramagnetic iron oxide nanoparticles (ASPION and PSPION) and Carbon dots (Cdts) were synthesised separately. ASPIONs and PSPIONs were further chemically conjugated with Cdts and developed dual-functional nanohybrid particles ASPION-Cdts and PSPION-Cdts. Subsequently, evaluation of the materials for its size, functionalisation efficiency, fluorescence and magnetic properties, biocompatibility and cellular uptake efficiency has been carried out. Fluorescence imaging of liver fibrosis was performedin vivoin rodent model of liver fibrosis using the two nanohybrids, which is further confirmed by high fluorescence signal from the harvested liver.
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    Glial and cartilagenous differentiation in medulloblastoma--a case report.
    (Indian journal of pathology & microbiology, 1994)
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    Intraventricular neurocytoma: a report of two cases.
    (Indian journal of cancer, 1994)
    Central neurocytomas are uncommon intracranial neoplasms. More than one hundred cases are documentated in the literature. In this report we describe the clinical and histopathological features in two patients with intraventricular neurocytoma. As the light microscopic features of neurocytoma resemble with that of an oligodendroglioma, it is essential to differentiate these two tumours, using either ultrastructural or immunohistochemical techniques.
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    Lymphocytic hypophysitis--a report of a case.
    (Indian journal of pathology & microbiology, 1995)
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    Magnetic nanoparticles for liver imaging.
    (Nature India. 2013, 2013-12) Saraswathy, A; Nazeer, SS; Nimi, N; Arumugam, S; Shenoy, SJ; Jayasree, RS
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    Mitochondrial myopathies--a clinicopathological study.
    (Indian journal of pathology & microbiology, 1998)
    Mitochondrial myopathies are heterogeneous group of clinical disorders that can affect multiple systems besides skeletal muscles. The mitochondrial abnormalities in the skeletal muscles are morphologically identified by the presence of characteristic Ragged-red fibers (RRF) in the cryostat sections of the muscle stained with modified Gomori's trichrome stain. In this retrospective study, clinical and histopathological features in six patients with mitochondrial myopathies have been analysed. The utility of histochemical methods in confirming the diagnosis of mitochondrial myopathy has been emphasised.
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    Multifunctional hybrid nanoconstruct of zerovalent iron and carbon dots for magnetic resonance angiography and optical imaging: An In vivo study
    (Biomaterials, 2018-07) Nimi, N; Saraswathy, A; Nazeer, SS; Francis, N; Shenoy, SJ; Jayasree, RS
    In magnetic resonance imaging (MRI), gadolinium (Gd) complexes are very often used as contrast agents to enhance the signal from soft tissue deformities and vascular anomalies, to improve the accuracy of diagnosis. The safety concern of using Gd complexes in renally compromised patients pose limitations on its application. To overcome this scenario, we introduce a nontoxic zerovalent iron based nanoparticle as a novel contrast agent for MR angiography and a hybrid version of the same to serve as a dual function contrast agent for targeted liver imaging. The synthesized zerovalent iron (ZVI) nanoparticles after citrate stabilization (C@ZVI) had an average size of 10 nm and exhibited paramagnetic property which is a prerequisite for a positive MRI contrast agent. The longitudinal magnetic relaxivity, r1 of C@ZVI was 4.93 mM-1s-1 which is much higher than that of clinically used Gd based agent, gadoterate meglumine (3.6 mM-1s-1). For multimodal imaging of the liver, initially the ZVI nanoparticle was tailored with a highly liver specific polysaccharide pullulan, and later with fluorescent carbon dots (Cdts) facilitating both optical and MR imaging. The magnetic relaxivity was retained in P@ZVI-Cdts for T1 contrast imaging with an r1 value of 3.48 mM-1s-1. The in vivo MR angiogram using C@ZVI and the liver targeted MRI and optical imaging using P@ZVI-Cdts were successfully demonstrated proving their potential as MRA contrast agent and a liver specific multimodal imaging agent.
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    Near infrared-emitting multimodal nanosystem for in vitro magnetic hyperthermia of hepatocellular carcinoma and dual imaging of in vivo liver fibrosis
    (Scientific Reports, 2023-08) Nazeer, SS; Saraswathy, A; Nimi, N; Santhakumar, H; Radhakrishnapillai Suma, P; Shenoy, SJ; Jayasree, RS
    Prolonged usage of traditional nanomaterials in the biological field has posed several short- and long-term toxicity issues. Over the past few years, smart nanomaterials (SNs) with controlled physical, chemical, and biological features have been synthesized in an effort to allay these challenges. The current study seeks to develop theranostic SNs based on iron oxide to enable simultaneous magnetic hyperthermia and magnetic resonance imaging (MRI), for chronic liver damage like liver fibrosis which is a major risk factor for hepatocellular carcinoma. To accomplish this, superparamagnetic iron oxide nanoparticles (SPIONs) were prepared, coated with a biocompatible and naturally occurring polysaccharide, alginate. The resultant material, ASPIONs were evaluated in terms of physicochemical, magnetic and biological properties. A hydrodynamic diameter of 40 nm and a transverse proton relaxation rate of 117.84 mM−1 s−1 pronounces the use of ASPIONs as an efficient MRI contrast agent. In the presence of alternating current of 300 A, ASPIONs could elevate the temperature to 45 °C or more, with the possibility of hyperthermia based therapeutic approach. Magnetic therapeutic and imaging potential of ASPIONs were further evaluated respectively in vitro and in vivo in HepG2 carcinoma cells and animal models of liver fibrosis, respectively. Finally, to introduce dual imaging capability along with magnetic properties, ASPIONs were conjugated with near infrared (NIR) dye Atto 700 and evaluated its optical imaging efficiency in animal model of liver fibrosis. Histological analysis further confirmed the liver targeting efficacy of the developed SNs for Magnetic theranostics and optical imaging as well as proved its short-term safety, in vivo.