861 |
Melatonin : a new factor in wound healingPugazhenthi, Kamali, n/a January 2008 (has links)
Wound healing is a dynamic process that ultimately leads to restoration of tissue integrity and function. The pineal gland hormone melatonin is known for its anti-oncotic, anti- inflammatory and immuno-modulatory effects. However, its role in wound healing has not been established.
Since melatonin is synthesised endogenously, we primarily sought to investigate whether the melatonin receptors played a role in the wound healing process. Using immunohistochemical methods and Western blot analysis we observed that MT₁ was normally absent in the rat skin but was strongly expressed on day 1 to day 3 post wounding in the epidermis adjacent to the wound edge. MT₁ expression was restricted to the stratum granulosum and stratum spinosum layers of the epidermis in the rat wounds. MT₁ expression declined thereafter and became nonexistent by day 21 when the wound had completely healed. In contrast, MT₂ was constitutively expressed in all the layers of the normal rat epidermis. MT₂ expression gradually decreased at the injury site following wounding but returned to the normal profile by day 21. Aged rat epidermis showed similar MT₁ and MT₂ expression as adult rats. The profile of tissue distribution of MT₁ and MT₂ in the human epidermis was comparable to the rat epidermis. In the CVUs MT₁ and MT₂ localisation profiles resembled that of a healing wound, akin to a day 1 or day 3 rat dermal wound, during the inflammatory phase. Surprisingly, in contrast to all the tissues investigated, MT₁ was also localised in the stratum basale layer of the keloid epidermis. MT₂ localisation in the same keloid tissues however resembled normal human skin profiles.
Secondly, we determined the effects of exogenously administered melatonin, on scarring and wound healing, using a full thickness incisional model of wound healing in rats. Melatonin treatment significantly improved the quality of scarring by day 21. However, our findings would have been strengthened by a more explicit wound closure analysis, measurement of granulation tissue weight, tensile strength, hydroxyl proline content and immunohistochemical assessments of neutrophil infiltration, macrophages, fibroblasts, myofibroblasts and reepithelialization. The treatment also accelerated the angiogenic process and enhanced the VEGF protein profile. Arginase generates proline, the building block for collagen synthesis. Melatonin treatment increased arginase activity and consequently would increase collagen synthesis from day 1. An increase in NOS activity and therefore NO production is known to be detrimental during inflammation. However, various studies have also shown that the NO is essential for granulation tissue formation. Melatonin treatment significantly decreased iNOS activity during the acute inflammatory phase in this study, but significantly increased iNOS activity during the resolving phase. Other markers of inflammatory response and repair were also examined in this study. COX-2 has been shown to play an anti-inflammatory role and melatonin increased COX-2 activity and protein following wounding. SOD (the antioxidant enzyme) activity was also significantly increased during the chronic inflammatory phase on melatonin administration. HO-1 and HO-2 isoforms have also been previously demonstrated to participate in the repair process. Melatonin treatment increased up-regulation of both HO-1 and HO-2 protein expression in the wounded skin. A significant decrease in all the mitochondrial enzyme activities (except complex-II-III), was observed post wounding. Melatonin treatment restored the complex activities to near normal levels. Melatonin also protected mitochondrial membrane integrity and reduced oxidative stress as evidenced by the maintained level of aconitase and citrate synthase activities at near normal levels.
In vitro experiments using macrophage and fibroblast cell lines illustrated that melatonin may decrease NOS activity and protein profiles indirectly by stimulating arginase activity and thereby depleting the availability of arginine.
This study is the first to fully demonstrate the distribution of melatonin receptors in normal and abnormal wounds. Improvement in the quality of scarring in a rat model of wound healing on melatonin administration is promising but much more quantitative work and preclinical studies are required before melatonin advances into clinical assessment.
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862 |
The role of dopamine in the control of gonadotropin and prolactin secretion in the human femaleJudd, Stephen John January 1978 (has links)
ix, 237 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D. 1979) from the Dept. of Obstetrics and Gynaecology, University of Adelaide
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863 |
Anticonvulsant drugs in immunosuppression and carcinogenesis / by Tania C. SorrellSorrell, Tania Christine January 1974 (has links)
[20] 172 [45] leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D. 1974) from the Dept. of Medicine, University of Adelaide
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864 |
Factors influencing the response of the rat tail artery to sympathomimetic amines / by Michael Gerard VenningVenning, Michael Gerard January 1982 (has links)
Typescript (photocopy) / 1 v. (various paging) : ill., (part col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pharmacology, 1982
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865 |
Energy balance and leptin in the fetus / Bernard Sin Jee Yuen.Yuen, Bernard Sin Jee January 2004 (has links)
Includes bibliographical references (leaves 165-225) / xx, 298 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Molecular and Biological Sciences, Discipline of Physiology, 2004
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866 |
Cell kinetics and residual damageTrainor, Kevin James. January 1980 (has links) (PDF)
No description available.
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867 |
Effect of nitrate and ammonium ions on the metabolism and growth of the tomato plant, Lycopersicum esculentum millWoolhouse, Harold W. January 1959 (has links) (PDF)
Typewritten Bibiography: leaves 209-222.
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868 |
Behavior of certain radionuclides in a marine benthic amphipodCross, Ford A. 22 August 1967 (has links)
Graduation date: 1968
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869 |
Role of oceanic heat transport processes in CO₂-induced warming : analysis of simulations by the OSU coupled atmosphere-ocean general circulation modelJiang, Xingjian 25 November 1986 (has links)
The OSU global coupled atmosphere/ocean general circulation
model (A/O GCM) has been used to simulate the present (lxCO₂)
climate and to investigate a CO₂-induced (2xCO₂) climate change.
Previous analysis of the lxCO₂ simulation showed distinct errors in
the simulated sea surface temperature (SST) and sea ice which were
attributed primarily to the atmospheric GM (AGCM). Analysis of
the 2xCO₂ simulation showed that the CO₂-induced warming penetrated
into the ocean; this caused a delay in the equilibration of the
climate system with an estimated e-folding time of 50-75 years.
The present study has two objectives. The principal objective is
to answer the question: By what pathways and through which physical
processes does the simulated ocean general circulation produce
the penetration of the CO₂-induced warming into the ocean? The
secondary objective is to evaluate the performance of the oceanic
GCM (OGCM) in the lxCO₂ simulation.
The comparison of the simulated lxCO₂ internal oceanic fields
with the corresponding observations shows that although they are
basically similar, there are distinct errors. Further analysis
shows that these errors were generated by the OGCM during its spin-up
integration prior to its coupling with the AGCM. This study
thus shows that it is not sufficient to compare the simulated SST
with the observed SST to evaluate the performance of the OGCM. It
is also necessary to compare the simulated internal oceanic quantities
with the corresponding observed quantities.
The global mean analysis of the CO₂-induced climate changes
shows that the ocean gains heat at a rate of 3 W/m² due to the CO₂
doubling. This heat penetrates downward into the ocean predominantly
through the reduction in the convective overturning. The
zonal mean analysis shows that the surface warming increased from
the tropics toward the mid-latitudes of both hemispheres and penetrated
gradually to the deeper ocean. The oceanic warming penetrated
to a greater depth in the subtropics and mid-latitudes than
in the equatorial region. A zonal mean heat budget analysis shows
that the CO₂-induced warming of the ocean occurs predominantly
through the downward transport of heat, with the meridional heat
flux being only of secondary importance. In the tropics the penetration
of the CO₂-induced heating is minimized by the upwelling of
cold water. In the subtropics the heating is transported downward
more readily by the downwelling existing there. In the high latitudes
the suppressed convection plays the dominant role in the
downward penetration of the CO₂-induced heating. / Graduation date: 1987
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870 |
Development of nickel aluminide (NiAl) microchannel array devices for high-temperature applicationsKanlayasiri, Kannachai 21 March 2003 (has links)
The miniaturization of Microtechnology-based Energy, Chemical and
Biological Systems (MECS) is made possible by the use of high aspect ratio
microchannel arrays to increase the surface-area-to-volume ratio of the flow
conduits within the devices, resulting in an improvement in the heat and mass
transfer performance of the devices. However, advantages of the MECS concept
cannot be applied to high-temperature applications (above 650��C) due to lack of
high-temperature MECS devices; therefore, the development of high-temperature
MECS devices is necessary to overcome this bottleneck. This dissertation involves
the development of high-temperature MECS devices from a high-temperature
material, nickel aluminide (NiAl). NiAl foil was synthesized from elemental nickel
(Ni) and aluminum (Al) foils through a two step process--tack bonding and
reactive diffusion. The elemental foils were tack bonded at 500��C, 3.9 MPa for
15 minutes. The reactive diffusion process was then performed through a heat
treatment at 1000��C for a period of time corresponding to the thickness of the
composite foil. The synthesized NiAl foil showed an atomic ratio of Al to Ni up to
0.96. The foil also showed a decent flatness and surface roughness. This
dissertation proposes a reactive diffusion bonding as a joining technique of nickel
aluminides. An investigation of bonding parameter effects on the warpage of
nickel aluminide fins in the reactive diffusion bonding process was performed.
Results showed that bonding time and temperature had significant effects on
warpage of the fin. The fin warpage increased with the increase of bonding time
and bonding temperature. Results also suggested that the bonding pressure had an
effect on the fin warpage. However, chemical compositions of the fin were not
significant to the warpage. This research also proposes a new fabrication procedure
for producing NiAl MECS devices. NiAl foils were used as the starting material,
and the reactive diffusion bonding technique was employed as the joining
technique. The research outcome indicated the viability of the proposed method in
fabricating NiAl MECS devices. This method achieved leak-tight devices with a
reasonable fin flatness. / Graduation date: 2003
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