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Papers by Kalyana Sundaram M.S

Research paper thumbnail of Fuzzy Corner Metric Based Brain Tumor Segmentation And Grade Classification

Current Signal Transduction Therapy, 2019

Background: The main idea this work is to reduce the physician time by assessing with computer ai... more Background: The main idea this work is to reduce the physician time by assessing with computer aided tumor detection Human investigation is the routine technique for brain MRI tumor detection and tumors classification. Interpretation of images is based on organized and explicit classification of brain MRI and also various techniques have been proposed. Methods: The proposed system segments the Brain MR images with the help of fuzzy corner points and the segmented tumor area is subjected for grade classification. Support vector machine classifier is implemented for the grade classification. Result & Conclusion: The proposed system is addressing a simple and robust technique for the tumor diagnosis and also the performance is 89.5% which is comparatively high when compared to the traditional classification method.

Research paper thumbnail of Impact of Urbanization on Water Resources –A Case Study of Ooty

Research paper thumbnail of Cholinergic nerve terminals in the ventrolateral medullary pressor area: pharmacological evidence

Journal of the Autonomic Nervous System, 1988

This investigation was designed to demonstrate the presence of cholinergic nerve terminals in the... more This investigation was designed to demonstrate the presence of cholinergic nerve terminals in the pressor area of the ventrolateral medulla (VLPA) and to study the effects of the release of endogenous acetylcholine in this area. Bilateral microinjections (0.1-2 nmol)/site) of 3,4-diaminopyridine (DAP), which releases acetylcholine from cholinergic nerve terminals, into the VLPA in anesthetized rats evoked an increase in blood pressure and heart rate which lasted for 20-40 min. Intravenous injections of the same doses of this agent failed to evoke a response. The ganglion blocker, chlorisondamine (3 mg/kg, i.v.) abolished the responses to microinjections of DAP indicating that the responses were mediated by the sympathetic nervous system. Microinjections of scopolamine or a specific M2 muscarinic receptor antagonist (AFDX-116) into the VLPA prevented the pressor and tachycardic responses to subsequent microinjections of DAP at the same sites indicating that the responses were mediated via M2 receptors. Microinjections of hemicholinium (3 nmol/site; which impairs acetylcholine synthesis) attenuated the responses to the subsequent microinjections of DAP at the same sites. These results indicate that the substance released from the terminals in the VLPA may be predominantly acetylcholine which evokes pressor and tachycardic responses via M2 muscarinic receptors. The origin and physiological significance of these cholinergic terminals in the VLPA are not known.

Research paper thumbnail of Relative effects of different spinal autonomic nuclei on cardiac sympathoexcitatory function

Brain Research Bulletin, 1990

MURUGAIAN, J., K. SUNDARAM, A. KRIBGER AND H. SAPRU. Relative effects of dr#erent spinal autonomi... more MURUGAIAN, J., K. SUNDARAM, A. KRIBGER AND H. SAPRU. Relative effects of dr#erent spinal autonomic nuclei on cardiac symputhoexcitatory function. BRAIN RBS BULL 24(4) 537-542, 1990.-Mean arterial pressure and heart rate were monitored in ~obili~ and artificially ventilated male Wistar rats either anesthetized with pentobarbital or decerebrated at ~dco~icui~ level. The rate of increase in the left ventricutar pressure was also monitored in order to compute contractility index. L-ghnamate (1.77 nmole) was microinjected (10 nl) into the following autonomic nuclei of the spinal cord at Cs to T4 levels: 1) intermediolateral column (&IL), 2) n. intercalatus spinalis (IC) and 3) n. intercaiatus pars paraependymahs (ICpe); this region is commonly known as the central autonomic area (CA). The site of microinjection was marked by injection of a dye; these studies suggested that microinjections of glutamate into the &IL are likely to encompass the neurons in the nucleus (n.) intermediolateralis thoracolumbalis pars principalis (ILp) and n. intermediolaterahs thoracolumbalis pars funicularis (IL& Sympathoexcitatory cardiac responses to glutamate microinjections were elicited from T, to T, levels; these responses could not be evoked at C, and T,, levels. In each of these segments, ~irn~ responses were obtained from the IML while the responses evoked from the IC and the CA were minimal. These results suggest that at T, to Ts levels of the spinal cord, IML is the main cell group regulating sympathetic cardiac function; CA and IC may play a &atively minor rote in this function. Blood pressure Contractility Heart rate Glutamate Wistar rat

Research paper thumbnail of Cardiac responses to the microinjections of excitatory amino acids into the intermediolateral cell column of the rat spinal cord

Brain Research, 1989

Sympathoexcitatory cardiovascular responses to the microinjections of L-glutamate into the interm... more Sympathoexcitatory cardiovascular responses to the microinjections of L-glutamate into the intermediolateral cell column (IML) of the upper thoracic cord (C s to T4) were studied. Mean arterial pressure (MAP), heart rate (HR), the rate of increase in the left ventricular pressure (dP/dt) and contractility index were monitored in immobilized and artificially ventilated male Wistar rats anesthetized with pentobarbital or isofluorane. On the right side, microinjections (10-20 nl) of L-glutamate (0.9-1.77 nmol in 0.9% sodium chloride solution, pH 7.4) into the IML at T 2 level produced marked tachycardic responses with relatively small changes in contractility. On the left side, similar microinjections produced marked increase in dP/dt and contractility index with relatively small increase in HR. On either side, the responses were smaller at T 1 and T 3 level and absent at C 8 and T 4 level. No changes in blood pressure were observed with microinjections of L-glutamate on either side. Microinjections of N-methyl-o-aspartic acid (NMDA), 1-100 pmol, into the IML elicited responses similar to those of L-glutamate. These amino acids failed to evoke any response when microinjected into the adjacent areas (e.g. 0.5 mm lateral or medial to the IML). The effects of glutamate and NMDA in the IML were blocked by microinjections of glntamic acid diethylester (GDEE) and D-2-amino-7-phosphonoheptanoic acid (D-AP7), respectively. Control microinjections of physiological saline into the IML produced no responses. These results indicate that excitatory amino acids, in small doses and volumes, can be used to identify cardiac sympathoexcitatory neuronal pools in the IML. This preparation may prove useful in characterizing pharmacological actions of various putative neurotransmitters in this region of the spinal cord. Male Wistar rats (Charles River Farms, MA), weighing 300-350 g, were used. The rats were anes

Research paper thumbnail of M2 muscarinic receptors mediate pressor responses to cholinergic agonists in the ventrolateral medullary pressor area

Brain Research, 1988

Microinjections of cholinergic agonists into the ventrolateral medullary pressor area (VLPA) evok... more Microinjections of cholinergic agonists into the ventrolateral medullary pressor area (VLPA) evoke increase in blood pressure (BP) and heart rate (HR). Recently two major subtypes of muscarinic receptors (M1 and M2) have been identified. This investigation was designed to study the role of these muscarinic receptor subtypes in pressor responses of cholinergic agonists in the VLPA. Male Wistar rats were anesthetized with pentobarbital or decerebrated at mid-collicular level. The rats were artificially ventilated and BP and HR were recorded. Ventral medulla was exposed and the VLPA identified bilaterally by microinjections of L-glutamate. Microinjections of cis-methyldioxolane (CD, a specific agonist of M2 receptors) in the doses of 0.004-4 nanomol (nmol)/site into the VLPA evoked an increase in BP (13-56 mm Hg) and HR (7-24 bpm) which lasted for 10-50 min. Intravenous injections of the same doses of this agent failed to evoke a response. AFDX-116 (a specific M2 muscarinic receptor antagonist) microinjected into the VLPA (0.2-1.6 nmol-/site) evoked depressor responses (6-20 mm Hg). Microinjections of this agent into the VLPA prevented the pressor responses to subsequent microinjections of CD at the same sites, indicating that AFDX-116 blocked M2 receptors. AFDX-116 rendered neurons in the VLPA unresponsive to L-glutamate but this effect lasted for 30-40 min while the hypotensive and M2 receptor blocking effect lasted for 60-150 min. McN-A343 (a specific agonist for M1 receptors) or pirenzepine (PZ, a specific antagonist of M1 receptors) injected into the VLPA (0.4-4 nmol/site) failed to evoke any response.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Cholinergic mechanisms in the ventrolateral medullary depressor area

Brain Research, 1989

Cardiovascular actions of cholinergic agonists in the ventrolateral medullary depressor area (VLD... more Cardiovascular actions of cholinergic agonists in the ventrolateral medullary depressor area (VLDA) were investigated. Microinjections (0.2-1.6 nmol/site) of an M 2 muscarinic receptor agonist (cis-methyldioxolane; CD) into the VLDA decreased blood pressure (33-71 mm Hg) and heart rate (11-62 beats/min). Microinjections of AFDX-116 (a specific blocker for M 2 receptors), but not those of pirenzepine (a specific blocker for M 1 receptors), prevented the depressor responses induced by CD. Unilateral microinjections of CD (0.3 nmol) into the VLDA also elicited depressor and bradycardic effects which were blocked by microinjections of bicuculline methiodide (200 pmol) into the ipsilateral ventrolateral medullary pressor area (VLPA). Bilateral vagotomy did not alter the depressor and bradycardic actions of CD in the VLDA. McN-A343 (2-3 nmol/site), an M 1 receptor agonist, failed to evoke any response when microinjected into the VLDA. These results indicate that muscarinic receptors of the M 2 type are present in the VLDA. Activation of the latter by cholinergic agonists results in depressor and bradycardic responses. These responses are mediated via the VLPA.

Research paper thumbnail of M2 muscarinic receptor agonists produce hypotension and bradycardia when injected into the nucleus tractus solitarii

Brain Research, 1989

Bilateral microinjections (0.2-2 nmol/site) of a potent M2 muscarinic receptor agonist, cis-methy... more Bilateral microinjections (0.2-2 nmol/site) of a potent M2 muscarinic receptor agonist, cis-methyldioxolane (CD), but not those of a relatively selective M1 receptor agonist (McN-A343; 3 nmol/site), into the intermediate portion of nucleus tractus solitarii (NTS) of pentobarbital-anesthetized rats elicited a decrease in blood pressure (23-52 mm Hg) and heart rate (16-50 bpm). Previous microinjections of a selective competitive M2 receptor antagonist (AFDX-116; 0.8 nmol/site), but not those of a potent selective M1 receptor antagonist (pirenzepine; 2 nmol/site), into the NTS blocked the effects of CD. These results indicate that the muscarinic receptors in the intermediate portion of NTS are of M2 type.

Research paper thumbnail of Electrolytic lesions in the depressor area of the ventrolateral medulla of the rat abolish depressor responses to the aortic nerve stimulation

Brain Research, 1989

The pressor (VLPA) and the depressor (VLDA) areas in the ventrolateral medulla were identified wi... more The pressor (VLPA) and the depressor (VLDA) areas in the ventrolateral medulla were identified with the microinjections of L-glutamate (1.77 nmoi/site) in artificially ventilated, pentobarbital-anesthetized male Wistar rats. Electrical stimulation of the left or right aortic nerve (1-6 V, 10-40 pulses/s, 3 ms) produced usual depressor responses. Electrolytic lesions (2.5 mA for 30 s) were placed bilaterally in the VLDA. Lack of responses to subsequent microinjections of glutamate into the VLDA indicated that the lesions were complete. The function of the VLPA was not compromised because it continued to respond to microinjections of glutamate. Subsequent stimulation of the aortic nerves failed to elicit the usual depressor responses. These results confirm our earlier reports indicating that the VLDA is important in mediating the depressor component of the aortic baroreflex.

Research paper thumbnail of Fuzzy Corner Metric Based Brain Tumor Segmentation And Grade Classification

Current Signal Transduction Therapy, 2019

Background: The main idea this work is to reduce the physician time by assessing with computer ai... more Background: The main idea this work is to reduce the physician time by assessing with computer aided tumor detection Human investigation is the routine technique for brain MRI tumor detection and tumors classification. Interpretation of images is based on organized and explicit classification of brain MRI and also various techniques have been proposed. Methods: The proposed system segments the Brain MR images with the help of fuzzy corner points and the segmented tumor area is subjected for grade classification. Support vector machine classifier is implemented for the grade classification. Result & Conclusion: The proposed system is addressing a simple and robust technique for the tumor diagnosis and also the performance is 89.5% which is comparatively high when compared to the traditional classification method.

Research paper thumbnail of Impact of Urbanization on Water Resources –A Case Study of Ooty

Research paper thumbnail of Cholinergic nerve terminals in the ventrolateral medullary pressor area: pharmacological evidence

Journal of the Autonomic Nervous System, 1988

This investigation was designed to demonstrate the presence of cholinergic nerve terminals in the... more This investigation was designed to demonstrate the presence of cholinergic nerve terminals in the pressor area of the ventrolateral medulla (VLPA) and to study the effects of the release of endogenous acetylcholine in this area. Bilateral microinjections (0.1-2 nmol)/site) of 3,4-diaminopyridine (DAP), which releases acetylcholine from cholinergic nerve terminals, into the VLPA in anesthetized rats evoked an increase in blood pressure and heart rate which lasted for 20-40 min. Intravenous injections of the same doses of this agent failed to evoke a response. The ganglion blocker, chlorisondamine (3 mg/kg, i.v.) abolished the responses to microinjections of DAP indicating that the responses were mediated by the sympathetic nervous system. Microinjections of scopolamine or a specific M2 muscarinic receptor antagonist (AFDX-116) into the VLPA prevented the pressor and tachycardic responses to subsequent microinjections of DAP at the same sites indicating that the responses were mediated via M2 receptors. Microinjections of hemicholinium (3 nmol/site; which impairs acetylcholine synthesis) attenuated the responses to the subsequent microinjections of DAP at the same sites. These results indicate that the substance released from the terminals in the VLPA may be predominantly acetylcholine which evokes pressor and tachycardic responses via M2 muscarinic receptors. The origin and physiological significance of these cholinergic terminals in the VLPA are not known.

Research paper thumbnail of Relative effects of different spinal autonomic nuclei on cardiac sympathoexcitatory function

Brain Research Bulletin, 1990

MURUGAIAN, J., K. SUNDARAM, A. KRIBGER AND H. SAPRU. Relative effects of dr#erent spinal autonomi... more MURUGAIAN, J., K. SUNDARAM, A. KRIBGER AND H. SAPRU. Relative effects of dr#erent spinal autonomic nuclei on cardiac symputhoexcitatory function. BRAIN RBS BULL 24(4) 537-542, 1990.-Mean arterial pressure and heart rate were monitored in ~obili~ and artificially ventilated male Wistar rats either anesthetized with pentobarbital or decerebrated at ~dco~icui~ level. The rate of increase in the left ventricutar pressure was also monitored in order to compute contractility index. L-ghnamate (1.77 nmole) was microinjected (10 nl) into the following autonomic nuclei of the spinal cord at Cs to T4 levels: 1) intermediolateral column (&IL), 2) n. intercalatus spinalis (IC) and 3) n. intercaiatus pars paraependymahs (ICpe); this region is commonly known as the central autonomic area (CA). The site of microinjection was marked by injection of a dye; these studies suggested that microinjections of glutamate into the &IL are likely to encompass the neurons in the nucleus (n.) intermediolateralis thoracolumbalis pars principalis (ILp) and n. intermediolaterahs thoracolumbalis pars funicularis (IL& Sympathoexcitatory cardiac responses to glutamate microinjections were elicited from T, to T, levels; these responses could not be evoked at C, and T,, levels. In each of these segments, ~irn~ responses were obtained from the IML while the responses evoked from the IC and the CA were minimal. These results suggest that at T, to Ts levels of the spinal cord, IML is the main cell group regulating sympathetic cardiac function; CA and IC may play a &atively minor rote in this function. Blood pressure Contractility Heart rate Glutamate Wistar rat

Research paper thumbnail of Cardiac responses to the microinjections of excitatory amino acids into the intermediolateral cell column of the rat spinal cord

Brain Research, 1989

Sympathoexcitatory cardiovascular responses to the microinjections of L-glutamate into the interm... more Sympathoexcitatory cardiovascular responses to the microinjections of L-glutamate into the intermediolateral cell column (IML) of the upper thoracic cord (C s to T4) were studied. Mean arterial pressure (MAP), heart rate (HR), the rate of increase in the left ventricular pressure (dP/dt) and contractility index were monitored in immobilized and artificially ventilated male Wistar rats anesthetized with pentobarbital or isofluorane. On the right side, microinjections (10-20 nl) of L-glutamate (0.9-1.77 nmol in 0.9% sodium chloride solution, pH 7.4) into the IML at T 2 level produced marked tachycardic responses with relatively small changes in contractility. On the left side, similar microinjections produced marked increase in dP/dt and contractility index with relatively small increase in HR. On either side, the responses were smaller at T 1 and T 3 level and absent at C 8 and T 4 level. No changes in blood pressure were observed with microinjections of L-glutamate on either side. Microinjections of N-methyl-o-aspartic acid (NMDA), 1-100 pmol, into the IML elicited responses similar to those of L-glutamate. These amino acids failed to evoke any response when microinjected into the adjacent areas (e.g. 0.5 mm lateral or medial to the IML). The effects of glutamate and NMDA in the IML were blocked by microinjections of glntamic acid diethylester (GDEE) and D-2-amino-7-phosphonoheptanoic acid (D-AP7), respectively. Control microinjections of physiological saline into the IML produced no responses. These results indicate that excitatory amino acids, in small doses and volumes, can be used to identify cardiac sympathoexcitatory neuronal pools in the IML. This preparation may prove useful in characterizing pharmacological actions of various putative neurotransmitters in this region of the spinal cord. Male Wistar rats (Charles River Farms, MA), weighing 300-350 g, were used. The rats were anes

Research paper thumbnail of M2 muscarinic receptors mediate pressor responses to cholinergic agonists in the ventrolateral medullary pressor area

Brain Research, 1988

Microinjections of cholinergic agonists into the ventrolateral medullary pressor area (VLPA) evok... more Microinjections of cholinergic agonists into the ventrolateral medullary pressor area (VLPA) evoke increase in blood pressure (BP) and heart rate (HR). Recently two major subtypes of muscarinic receptors (M1 and M2) have been identified. This investigation was designed to study the role of these muscarinic receptor subtypes in pressor responses of cholinergic agonists in the VLPA. Male Wistar rats were anesthetized with pentobarbital or decerebrated at mid-collicular level. The rats were artificially ventilated and BP and HR were recorded. Ventral medulla was exposed and the VLPA identified bilaterally by microinjections of L-glutamate. Microinjections of cis-methyldioxolane (CD, a specific agonist of M2 receptors) in the doses of 0.004-4 nanomol (nmol)/site into the VLPA evoked an increase in BP (13-56 mm Hg) and HR (7-24 bpm) which lasted for 10-50 min. Intravenous injections of the same doses of this agent failed to evoke a response. AFDX-116 (a specific M2 muscarinic receptor antagonist) microinjected into the VLPA (0.2-1.6 nmol-/site) evoked depressor responses (6-20 mm Hg). Microinjections of this agent into the VLPA prevented the pressor responses to subsequent microinjections of CD at the same sites, indicating that AFDX-116 blocked M2 receptors. AFDX-116 rendered neurons in the VLPA unresponsive to L-glutamate but this effect lasted for 30-40 min while the hypotensive and M2 receptor blocking effect lasted for 60-150 min. McN-A343 (a specific agonist for M1 receptors) or pirenzepine (PZ, a specific antagonist of M1 receptors) injected into the VLPA (0.4-4 nmol/site) failed to evoke any response.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Cholinergic mechanisms in the ventrolateral medullary depressor area

Brain Research, 1989

Cardiovascular actions of cholinergic agonists in the ventrolateral medullary depressor area (VLD... more Cardiovascular actions of cholinergic agonists in the ventrolateral medullary depressor area (VLDA) were investigated. Microinjections (0.2-1.6 nmol/site) of an M 2 muscarinic receptor agonist (cis-methyldioxolane; CD) into the VLDA decreased blood pressure (33-71 mm Hg) and heart rate (11-62 beats/min). Microinjections of AFDX-116 (a specific blocker for M 2 receptors), but not those of pirenzepine (a specific blocker for M 1 receptors), prevented the depressor responses induced by CD. Unilateral microinjections of CD (0.3 nmol) into the VLDA also elicited depressor and bradycardic effects which were blocked by microinjections of bicuculline methiodide (200 pmol) into the ipsilateral ventrolateral medullary pressor area (VLPA). Bilateral vagotomy did not alter the depressor and bradycardic actions of CD in the VLDA. McN-A343 (2-3 nmol/site), an M 1 receptor agonist, failed to evoke any response when microinjected into the VLDA. These results indicate that muscarinic receptors of the M 2 type are present in the VLDA. Activation of the latter by cholinergic agonists results in depressor and bradycardic responses. These responses are mediated via the VLPA.

Research paper thumbnail of M2 muscarinic receptor agonists produce hypotension and bradycardia when injected into the nucleus tractus solitarii

Brain Research, 1989

Bilateral microinjections (0.2-2 nmol/site) of a potent M2 muscarinic receptor agonist, cis-methy... more Bilateral microinjections (0.2-2 nmol/site) of a potent M2 muscarinic receptor agonist, cis-methyldioxolane (CD), but not those of a relatively selective M1 receptor agonist (McN-A343; 3 nmol/site), into the intermediate portion of nucleus tractus solitarii (NTS) of pentobarbital-anesthetized rats elicited a decrease in blood pressure (23-52 mm Hg) and heart rate (16-50 bpm). Previous microinjections of a selective competitive M2 receptor antagonist (AFDX-116; 0.8 nmol/site), but not those of a potent selective M1 receptor antagonist (pirenzepine; 2 nmol/site), into the NTS blocked the effects of CD. These results indicate that the muscarinic receptors in the intermediate portion of NTS are of M2 type.

Research paper thumbnail of Electrolytic lesions in the depressor area of the ventrolateral medulla of the rat abolish depressor responses to the aortic nerve stimulation

Brain Research, 1989

The pressor (VLPA) and the depressor (VLDA) areas in the ventrolateral medulla were identified wi... more The pressor (VLPA) and the depressor (VLDA) areas in the ventrolateral medulla were identified with the microinjections of L-glutamate (1.77 nmoi/site) in artificially ventilated, pentobarbital-anesthetized male Wistar rats. Electrical stimulation of the left or right aortic nerve (1-6 V, 10-40 pulses/s, 3 ms) produced usual depressor responses. Electrolytic lesions (2.5 mA for 30 s) were placed bilaterally in the VLDA. Lack of responses to subsequent microinjections of glutamate into the VLDA indicated that the lesions were complete. The function of the VLPA was not compromised because it continued to respond to microinjections of glutamate. Subsequent stimulation of the aortic nerves failed to elicit the usual depressor responses. These results confirm our earlier reports indicating that the VLDA is important in mediating the depressor component of the aortic baroreflex.