Balarama Kaimal, S; Dr.Paulose, C S(Cochin University of Science & Technology, July , 2005)
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Abstract:
The present study demonstrate the functional alterations of the GABAA and GABAB
receptors and the gene expression during the regeneration of pancreas following
partial pancreatectomy. The role of these receptors in insulin secretion and
pancreatic DNA synthesis using the specific agonists and antagonists also are studied
in vitro. The alterations of GABAA and GABAR receptor function and gene
expression in the brain stem, crebellum and hypothalamus play an important role in
the sympathetic regulation of insulin secretion during pancreatic regeneration.
Previous studies have given much information linking functional interaction between
GABA and the peripheral nervous system. The involvement of specific receptor
subtypes functional regulation during pancreatic regeneration has not given emphasis
and research in this area seems to be scarce. We have observed a decreased GABA
content, down regulation of GABAA receptors and an up regulation of GABAB
receptors in the cerebral cortex, brain stem and hypothalamus. Real Time-PCR
analysis confirmed the receptor data in the brain regions. These alterations in the
GABAA and GABAB receptors of the brain are suggested to govern the regenerative
response and growth regulation of the pancreas through sympathetic innervation. In
addition, receptor binding studies and Real Time-PCR analysis revealed that during
pancreatic regeneration GABAA receptors were down regulated and GABAB
receptors were up regulated in pancreatic islets. This suggests an inhibitory role for
GABAA receptors in islet cell proliferation i.e., the down regulation of this receptor
facilitates proliferation. Insulin secretion study during 1 hour showed GABA has
inhibited the insulin secretion in a dose dependent manner in normal and
hyperglycaemic conditions. Bicuculline did not antagonize this effect. GABAA
agonist, muscimol inhibited glucose stimulated insulin secretion from pancreatic
islets except in the lowest concentration of 1O-9M in presence of 4mM glucose.Musclmol enhanced insulin secretion at 10-7 and 10-4M muscimol in presence of
20mM glucose- 4mM glucose represents normal and 20mM represent
hyperglycaemic conditions. GABAB agonist, baclofen also inhibited glucose induced
insulin secretion and enhanced at the concentration of 1O-5M at 4mM glucose and at
10-9M baclofen in presence of 20mM glucose. This shows a differential control of
the GABAA and GABAB receptors over insulin release from the pancreatic islets.
During 24 hours in vitro insulin secretion study it showed that low concentration of
GABA has inhibited glucose stimulated insulin secretion from pancreatic islets.
Muscimol, the GABAA agonist, inhibited the insulin secretion but, gave an enhanced
secretion of insulin in presence of 4mM glucose at 10-7
, 10-5 and 1O-4M muscimol.
But in presence of 20mM glucose muscimol significantly inhibited the insulin
secretion. GABAB agonist, baclofen also inhibited glucose induced insulin secretion
in presence of both 4mM and 20mM glucose. This shows the inhibitory role of
GABA and its specific receptor subtypes over insulin synthesis from pancreatic bete-islets.
In vitro DNA synthesis studies showed that activation of GABAA receptor by
adding muscimol, a specific agonist, inhibited islet DNA synthesis. Also, the
addition of baclofen, a specific agonist of GABAB receptor resulted in the stimulation
of DNA synthesis.Thus the brain and pancreatic GABAA and GABAB receptor
gene expression differentially regulates pancreatic insulin secretion and islet cell
proliferation during pancreatic regeneration. This will have immense clinical
significance in therapeutic applications in the management of Diabetes mellitus.
Description:
Department of Biotechnology,
Cochin University of Science and Technology
Biju,M P; Paulose,C S(Department of Biotechnology, 2000)
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Abstract:
The present thesis is an attempt to understand the role of GABA, GABAA and GABAB receptors in the regulation of liver cell proliferation using in vivo and in vitro models. The work also focuses on the brain GABAergic changes associated with normal and neoplastic cell growth in liver and to delineate its regulatory function. The investigation of mechanisms involving mitogenic models without cell necrosis may contribute our knowledge about both on cell growth, carcinogenesis, liver pathology and treatment. Objectives of the present study are, to induce controlled liver cell proliferation by partial hepatectomy and lead nitrate administration and uncontrolled cell proliferation by N-nitrosodiethylamine treatment in male Wistar rats, the changes in the content of GABA, GABAA,GABAB in various rat brain regions. To study the GABAA and GABAB receptor changes in brain stem, hypothalamus, cerebellum and cerebral cortex during the active cortex during the period of active DNA synthesis in liver of different experimental groups. The changes in GABAA and GABAB receptor function of the brain stem, hypothalamus and cerebellum play an important role sympathetic regulation of cell proliferation and neoplastic growth in liver. The decrease in GABA content in brain stem, hypothalamus and cerebellum during regeneration and neoplasia in liver. The time course of brain GABAergic changes was closely correlated with that of heptic DNA synthesis. The functional significance of these changes was further explored by studying the changes in GABAA and GABAB receptors in brain.
Anju, T R; Dr. Paulose, C S(Cochin University of Science and Technology, September , 2010)
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Abstract:
The present study was designed to investigate the protective effect of
glucose, oxygen and epinephrine resuscitation on impairment in the functional role
of GABAergic, serotonergic, muscarinic receptors, PLC, BAX, SOD, CAT and
GPx expression in the brain regions of hypoxia induced neonatal rats. Also, the
role of hormones - Triiodothyronine (T3) and insulin, second messengers –
cAMP, cGMP and IP3 and transcription factors – HIF and CREB in the regulation
of neonatal hypoxia and its resuscitation methods were studied. Behavioural
studies were conducted to evaluate the motor function and cognitive deficit in one
month old control and experimental rats. The efficient and timely supplementation
of glucose plays a crucial role in correcting the molecular changes due to hypoxia,
oxygen and epinephrine. The sequence of glucose, epinephrine and oxygen
administration at the molecular level is an important aspect of the study. The
additive neuronal damage effect due to oxygen and epinephrine treatment is
another important observation. The corrective measures by initial supply of
glucose to hypoxic neonatal rats showed from the molecular study when brought
to practice will lead to healthy intellectual capacity during the later developmental
stages, which has immense clinical significance in neonatal care.
Description:
Department of Biotechnology,
Cochin University of Science and Technology
LAKSHMANAN, APARNA; . RAO, S. B; Vijayakumar, A(February 4, 2010)
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Abstract:
Abstract. The paper deals with graph operators-the Gallai graphs and the anti-Gallai
graphs. We prove the existence of a finite family of forbidden subgraphs for the Gallai graphs
and the anti-Gallai graphs to be H-free for any finite graph H. The case of complement
reducible graphs-cographs is discussed in detail. Some relations between the chromatic
number, the radius and the diameter of a graph and its Gallai and anti-Gallai graphs are
also obtained.
This paper presents gamma stochastic volatility models and investigates its distributional
and time series properties. The parameter estimators obtained by the
method of moments are shown analytically to be consistent and asymptotically
normal. The simulation results indicate that the estimators behave well. The insample
analysis shows that return models with gamma autoregressive stochastic
volatility processes capture the leptokurtic nature of return distributions and
the slowly decaying autocorrelation functions of squared stock index returns
for the USA and UK. In comparison with GARCH and EGARCH models, the
gamma autoregressive model picks up the persistence in volatility for the US
and UK index returns but not the volatility persistence for the Canadian and
Japanese index returns. The out-of-sample analysis indicates that the gamma
autoregressive model has a superior volatility forecasting performance compared
to GARCH and EGARCH models.
Lalithabhai,K N; Sankaranarayanan,K C(Department of Applied Economics, Faculty of Social Sciences, 2003)
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Abstract:
Women participating in work outside home and the resultant change in Labour market structure placeing female labour as a strong component were breakthrough of twentieth centry. The major share of women labourers in India is crowding in agriculture, household industries and other traditional sectors. Shift in cropping pattern has adverse impacts on female labour. Female labour lost opportunities in the labour market this has adverse impact on family consumption. The study is directed to investigate the impact of female labour saving shift in cropping on female labour force participation and the resultant change in household consumption pattern the specific objectives this study are impact of change in the cropping pattern on employment, change female employment, family consumption pattern and changing situations of womenlabour in agriculture sector.
Swapna,T S; Padma Nambisan(Department of Biotechnology, March , 2000)
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Abstract:
The study deals with the generation of variability for salt tolerance in rice using tissue culture techniques. Rice is the staple food of more than half of the world’s population. The management of drought, salinity and acidity in soils are all energy intensive agricultural practices. The Genetic variability is the basis of crop improvement. Somaclonal and androclonal variation can be effectively used for this purpose. In the present study, eight isozymes were studied and esterase and isocitric dehydrogenase was found to have varietal specific, developmental stage specific and stress specific banding pattern in rice. Under salt stress thickness of bands and enzyme activity showed changes. Pokkali, a moderately salt tolerant variety, had a specific band 7, which was present only in this variety and showed slight changes under stress. This band was faint in tillering and flowering stage .Based on the results obtained in the present study it is suggested that esterase could possibly be used as an isozyme marker for salt tolerance in rice. Varietal differences and stage specific variations could be detected using esterase and isocitric dehydrogenase . Moreover somaclonal and androclonal variation could be effectively detected using isozyme markers.
The thesis deals with the results of the study of the population characteristics of the marine penaeid prawn, Penaeus monodon from South India. The present findings on the morphometric and biochemical genetic structure support the hypothesis that the populations of P.monodon of South India have homogeneous stock structure. To the contrary, the significantly different random amplified polymorphic DNA (RAPD) profiles in samples of Kochi and Chennai support the hypothesis that east and west cost populations of P.monodon are separate stocks.
Reji,Srinivas; Sajan,K(Department of Marine Geology and Geophysics, School of marine Sciences, 2002)
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Abstract:
In this study, an attempt has been made to find the textural, geochemical, sedimentological characteristics of sediments and water phases of the kayamkulam estuary located in the Southwest coast of Kerala, besides the impact of gas based thermal power plant located at the northern part of the estuary. Estuaries are an important stage in the transport of the solid weathering product of the earth’s crust. These weathered products or sediments are complex mixtures of a number of solid phases that may include clays, silica, organic matter, metal oxides, carbonates, sulfides and a number of minerals. Studies on the aquatic systems revealed the fact that it posses severe ecological impairments due to heavy discharge of sediments from 44 rivers, the continued disposal of pollutants rich materials from industries, sewage channels, agricultural areas and retting yards
Hariharan,G N; Nambiar,C G(Department of Marine Geology & Geophysics, School of Marine Sciences, 2001)
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Abstract:
The present work deals with the texture, mineralogy and geochemistry of bedload sediments of the main stream of the Chaliyar basin, a typical small drainage system of the tropics enjoying heavy rain fall and moderate climate, located essentially in the Northern Kerala and flowing over the crystalline rocks (and their laterized duricrust) of the South Indian granulite terrain. As the Chaliyar is the major river draining the Wynad Gold Fields and is known for its placer gold occurrences, the thesis gives special emphasize on understanding the nature and distribution of detrital gold in sediments of the basin, while attempting to infer the provenance characteristics and factors involved in the evolution of sediments in general. Minerologically the chaliyar basin sands are quartzose. The quartz and feldspar contents in the coarse sand fraction of the basin range from 64 to 86% and 2 to 16% respectively. The Q/F ration ranges from 4 to 38 with a slight decrease in the lower reaches. Other minerals present include, hornblende, pyroxene and heavy minerals like opaques, garnet, rutile, biotite, spene, silliminite, zircon, apatite and monazite some of which are seen as inclusions in quartz. The major element composition of Chaliyar bedload sediments in the main channel and the headwater tributaries is related to the mineralogical and textual characteristics of sediments.
Siby,Varghese; Chandramohanakumar,N(National Institute of Oceanography & CUSAT, 2003)
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Abstract:
Rare earth elements have occupied an important role in marine geochemical research, particularly as used in the format of REE abundance patterns to describe the geochemical pathways in marine sedimentation and authigenesis. This study concentrates on the distribution pattern of Rare earth elements in the sediments, behavior of Eu and Ce with respect to their occurrence in multiple oxidation states. It also concentrate the depth wise variation of sediment REEs from near shore areas (30m) to deeper depths 200m) in the Arabian Sea. It includes the downcore variation of REEs and other trace elements in the sediment cores and a comparison between the REE distributions of Arabian Sea sediment with the sediments of Andaman Sea. The study gives a general introduction regarding the importance of RRE studies, its occurrence and abundance, electronic configuration, lanthanide contraction, oxidations states and REE supply to the ocean, seawater and sediments.
Laluraj, C M; Dr. Muraleedharan Nair, S(Cochin University of Science and Technology, February , 2009)
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Abstract:
The metals present in the surface sediments have high demand on a
global perspective, and the main reservoir of these elements is believed to be
the ocean floor. A lot of studies on metals are going on throughout the world
for its quantification and exploitation. Even though, some preliminary
attempts have been made in selected areas for the quantitative study of
metals in the western continental shelf of India, no comprehensive work has
been reported so far. The importance of this study also lies on the fact that
there has not been a proper evaluation of the impact of the Great Tsunami of
2004 on the coastal areas of the south India. In View of this, an attempt has
been made to address the seasonal distribution, behavior and mechanisms
which control the deposition of metals in the sediments of the western
continental shelf and Cochin Estuary, an annex to this coastal marine region.Surface sediment samples were collected seasonally from two
subenvironemnts of southwest coast of India, (continental shelf of Kerala and
Cochin estuarine system), to estimate the seasonal distribution and geochemical
behavior of non-transition, transition, rare-earth elements, Th and U. Bottom
water samples were also taken from each station, and analysed for temperature,
salinity and dissolved oxygen, hence the response of redox sensitive elements to
oxygen minimum zone can be addressed. In addition, other sedimentary
parameters such as sand, silt, clay fractions, CaCO3 and organic carbon content
were also estimated to evaluate the control factors on level of metals present in
the sediment. The study used different environmental data analysis techniques
to evaluate the distribution and behavior of elements during different seasons.
This includes environmental parameters such as elemental normalisation,
enrichment factor, element excess, cerium and europium anomalies and
authigenic uranium.
Description:
Department of Chemical Oceanography,Cochin University of Science and Technology