Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Darbo tikslas yra nustatyti galimus metabolinius pokyčius žmogaus danties pulpoje ortodontinio gydymo metu veikiant gramzdinimo jėgoms ir įvertinti šių jėgų įtaką pulpos gyvybingumui. Uždaviniai: 1. Nustatyti fermento aspartato aminotransferazės (toliau – AST) akty¬vumą sveikų dantų pulpos audinyje. 2. Nustatyti, kaip kinta danties pulpos AST aktyvumas veikiant dantis 7 ir 14 dienų nepertraukiama gramzdinimo jėga ir 7 dienų nepertrau¬kiama jėga su vėlesniu 7 dienų poilsiu bei palyginti šiuos aktyvumus su sveikų dantų pulpos AST fermento aktyvumu. 3. Įvertinti danties pulpos atsaką į dirginimą elektros srove, taikant elektroodontometrinio gyvybingumo testą (toliau – EPT) sveikiems ir dantims paveiktiems 7 ir 14 dienų nepertraukiama gramzdinimo jėga bei 7 dienų nepertraukiama jėga su vėlesniu 7 dienų poilsiu. 4. Atlikti jėgos, veikiančios ortodontinio krūvio metu, matematinę ana¬lizę. 5. Įvertinti galimą pulpos AST fermento aktyvumo bei pulpos EPT at¬sako ryšį su gramzdinimo jėgos dydžiu, dantų šaknų skaičiumi, žan¬dikaulio tipu, bei amžiumi. 6. Atlikti pacientų, kuriems radiografinis tyrimas taikytas odontolo¬ginio gydymo planavimui, skaitmeninių panoraminių radiogramų analizę, siekiant įvertinti pulpos akmenų pulpos kameroje ir šak¬ninėje pul¬poje paplitimą tarp jauno amžiaus pacientų. 7. Atlikti ortodontinių pacientų pirminių bei galutinių skaitmeninių pa¬no¬raminių radiogramų lyginamąją analizę, siekiant įvertinti pulpos akmenų paplitimą pulpos kameroje ir šakninėje... [toliau žr. visą tekstą] / The aim of the study was to evaluate metabolic alterations of the human dental pulp in response to application of intrusive forces, and to investigate impact of such forces on the pulp vitality.Objectives of the study: 1) to determine activity of aspartate aminotransferase (hereinafter – AST) in the dental pulp of teeth unaffected by orthodontic loading; 2) to evaluate changes in the dental pulp AST activity after appli¬cation of continuous intrusive force for 7 and for 14 days, or, continuous force for 7 days with the following 7 days of rest, and to compare the obtained values with the pulp AST activity in teeth unaffected by orthodontic loading; 3) to compare dental pulp response to electrical stimulation by means of electric odontometric pulp test (hereinafter – EPT) in teeth unaffected by orthodontic loading, and in teeth subjected to continuous intrusive force for 7 and for 14 days, also for 7 days of continuous loading with the following 7 days of rest; 4) to perform mathematical analysis of the forces acting during the orthodontic loading; 5) to analyse relation of the pulp AST activity and the EPT measu¬rements with the intrusive force magnitude, tooth type (i.e. number of tooth roots; maxilar or, mandibular), and patient‘s age; 6) to analyse digital panoramic X-ray images of the patients, sub¬jected to radiography during routine dental treatment planning, in order to observe occurence of pulp stones in the dental pulp chamber; 7) to compare baseline and final... [to full text]

<p>Camellia sinensis (tea) and Aspalathus linearis (rooibos) may improve reproductive function owing to their antioxidant properties. To test this<br /> hypothesis, male and female rats were given 2% and 5% green tea (Gt), black tea (Bt), unfermented rooibos (Ur) or fermented rooibos (Fr) as sole source of drinking for 52 and 21 days respectively. Control rats received tap water. In addition, TM3 Leydig cells were exposed to 0.025, 0.05, 0.1 and 0.5 % aqueous extracts of green tea, black tea, unfermented and fermented rooibos for 24h. In vitro analysis of tea and the herbal infusion revealed the phenolic property and antioxidant capacity (FRAP) in the order Gt &gt / Bt &gt / Ur &gt / Fr. Camellia sinensis and Aspalathus linearis revealed no significant effect on serum antioxidant capacity (p &gt / 0.05) and lipid peroxidation (MDA) in the kidney or liver in both male and female rats and in the testes of the male rats (p &gt / 0.05). In addition, the antioxidant levels were maintained in the testes, liver and kidneys in both the male and female rats. In the male rats, no significant alterations were observed in body weight gain, liver and reproductive organs weight, and serum testosterone (p &gt / 0.05). Only, 5% green tea significantly increased testosterone level (p &lt / 0.05). Seminiferous tubules displayed complete spermatogenesis with abundant sperm in the lumen in all treated groups. However, a significant decrease in diameter and germinal epithelial height of these tubules were observed (p &lt / 0.05). In the epididymides, epithelial height of caput region showed a significant increase (p &lt / 0.01), while the cauda region was increased by Camellia sinensis but decreased by Aspalathus linearis. Sperm concentration improved significantly by green tea and unfermented rooibos (p &lt / 0.05), while black tea and fermented rooibos produced a non significant effect (p &gt / 0.05). Sperm viability was enhanced in all treatment groups (p &lt / 0.05). Furthermore, green tea, black tea and unfermented rooibos significantly improved the motility of rat sperm (p &lt / 0.05) / fermented rooibos tended to improve it (p &gt / 0.05). In addition, green tea, black tea and fermented rooibos enhanced acrosome reaction (p &lt / 0.05). Creatinine activity was significantly higher in rats treated with black tea, unfermented rooibos or fermented rooibos (p &lt / 0.05), green tea tended to increase it (p &gt / 0.05) reflecting the significant increased kidney weight in the treatment groups at high concentrations. Liver markers, ALT and AST, decreased significantly in all treated groups (p &lt / 0.05), except in 5% fermented rooibos where a significant increase in AST level was observed (p &lt / 0.01). In the female rats, the body weight gain, and reproductive organs weight was no affected (p &gt / 0.05). However, 5% fermented rooibos reduced the ovarian weight (p &lt / 0.05), while 5% unfermented rooibos significantly increased the uterine weight (p &lt / 0.05). Liver weight increased significantly by black tea and unfermented rooibos (p &lt / 0.05) while the kidney weight increased significantly by 5% black tea (p &lt / 0.05). No significant effect was observed in the level of FSH produced, on the other hand, Camellia sinensis significantly lowered the level of LH (p &lt / 0.05), while Aspalathus linearis had no effect (p &gt / 0.05). Creatinine activity was enhanced significantly only by 5% fermented rooibos (p &lt / 0.05). Liver markers, ALT and AST were reduced in most treated groups except in fermented rooibos where an increase was observed. In addition, histological sections revealed no obvious alteration in the ovaries, uteri, kidneys and liver of all treated female rats. Camellia sinensis and Aspalathus linearis significantly reduced the level of testosterone produced in TM3 Leydig cells under stimulated conditions in vitro (p&lt / 0.05). Furthermore, both plants maintained the viability and morphology of the cells. However, at 0.5% of either plant extracts, a significant decrease in the viability (p &lt / 0.05) and altered morphology of the TM3 Leydig cells was observed. In conclusion, Camellia sinensis and Aspalathus linearis significantly improved certain sperm function which might be attributed to their high level of antioxidant activity. However, the prolonged exposure of both plant extracts might result in subtle structural changes in the male reproductive system and impair kidney function. In addition, fermented rooibos at high concentration may also impair the functions of the liver. In vitro, both plants were shown to possess anti-androgenic property on TM3 Leydig cells. Furthermore, both Camellia sinensis and Aspalathus linearis may be classified as weak phytoestrogens due to the changes in the weight of the uterus and ovaries observed.</p>

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Thesis (Ph.D. in Human Medical Genetics) -- University of Colorado at Denver and Health Sciences Center, 2005. / Typescript. Includes bibliographical references (leaves 166-195).

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / In the present work, behavioral, neurochemical (determination of monoamines and metabolites levels rat in striatum), histopatological and biochemical (lipoproteins and transaminases) alterations produced by cocaine, ethanol and the association of theses were analyzed. Females Wistar rats (180-200 g) were treated during 7 days with cocaine (Coc 10 and 20 mg/kg, i.p.), ethanol (Et 2 and 4g/kg, p.o.) and the association of theses (Coc 10 mg + Et 2g - low interaction doses; Coc 20 mg + Ethanol 4g - high interaction doses). The results demonstrated that the spontaneous locomotor activity (SLA) was increased after cocaine administration and decreased after ethanol in both doses. It was not observed alterations in the SLA in the association cocaine + ethanol. The treatment with cocaine and ethanol caused an increase in dopamine level. The association cocaine + ethanol in higher doses caused an increase of dopamine and serotonin and decrease of DOPAC levels, suggesting that those drugs would can actuate directly in those systems or, indirectly, across a process of modulation. Cocaine, ethanol and the association of theses, after subcronic administration and in both doses, caused a donwregulation of D2-like receptors, not by recurring alterations in the values of Kd. The values of Bmax and Kd of the M1 + M2-like receptors have not already suffered alterations. In the biochemical study, the administration of cocaine induced an increase the concentrations of TGO and triglycerides, and decrease of the concentrations of TGP, total cholesterol and HDL. The treatment with ethanol decreases the levels of HDL, total cholesterol and triglycerides. The association cocaine + ethanol caused in both doses decrease of triglycerides, HDL, TGP and total cholesterol. All treatments did promote histopatological alterations in cardiac and hepatic woven. Ours results suggest that the association cocaine + ethanol appears to interfere more intense in the systems of neurotransmitters and in the biochemical parameters than the use of the isolated drugs. / No presente trabalho foram estudadas as alteraÃÃes comportamentais, neuroquÃmicas (determinaÃÃes dos nÃveis de monoaminas e metabÃlitos), histopatolÃgicas e bioquÃmicas (lipoproteÃnas e transaminases) em corpo estriado de ratos tratados com cocaÃna e etanol isoladamente ou em associaÃÃo. Foram utilizadas ratas Wistar (180-200 g), que foram tratadas durante 7 dias com cocaÃna (Coc 10 e 20 mg/kg, i.p.), etanol (Et 2 e 4g/kg, v.o.) e a associaÃÃo destes (Coc 10 mg + Et 2g - interaÃÃo baixas doses; Coc 20 mg + Etanol 4g - interaÃÃo altas doses). Os resultados demonstraram que a atividade locomotora espontÃnea (ALE) foi aumentada apÃs administraÃÃo de cocaÃna em ambas as doses e diminuÃda apÃs a administraÃÃo de etanol em ambas as doses. NÃo foram observadas alteraÃÃes na ALE na associaÃÃo cocaÃna + etanol. O tratamento com cocaÃna e etanol causou um aumento de dopamina, sem alteraÃÃes nos demais neurotransmissores e metabÃlitos. A associaÃÃo cocaÃna + etanol em altas doses, promoveu aumento dos nÃveis de dopamina, diminuiÃÃo de DOPAC e aumento dos nÃveis de 5-HT, sugerindo que essas drogas poderiam atuar diretamente nesses sistemas ou, indiretamente, atravÃs de um processo de modulaÃÃo. A cocaÃna, etanol e a associaÃÃo destes, apÃs administraÃÃo sub-crÃnica e em ambas as doses, causou uma downregulation em receptores D2-sÃmile, nÃo ocorrendo alteraÃÃes nos valores de Kd. Os valores de Bmax e Kd dos receptores M1 + M2-sÃmile nÃo sofreram alteraÃÃes. No estudo bioquÃmico, a administraÃÃo de cocaÃna induziu um aumento nas concentraÃÃes de TGO e triglicerÃdeos, e diminuiÃÃo das concentraÃÃes de TGP, colesterol total e HDL. O tratamento com etanol diminuiu os nÃveis de HDL, colesterol total e triglicerÃdeos. A associaÃÃo cocaÃna + etanol promoveu em ambas as doses diminuiÃÃo de trigicerÃdeos, HDL, TGP e colesterol total. Todos os tratamentos promoveram alteraÃÃes histopatolÃgicas em tecido cardÃaco e hepÃtico. Nossos resultados sugerem que a associaÃÃo cocaÃna + etanol parece interferir de maneira mais intensa nos sistemas de neurotransmissÃo e nos parÃmetros bioquÃmicos do que o uso das drogas isoladas.

Philosophiae Doctor - PhD / Camellia sinensis (tea) and Aspalathus linearis (rooibos) may improve reproductive function owing to their antioxidant properties. To test this hypothesis, male and female rats were given 2% and 5% green tea (Gt), black tea (Bt), unfermented rooibos (Ur) or fermented rooibos (Fr) as sole source of drinking for 52 and 21 days respectively. Control rats received tap water. In addition, TM3 Leydig cells were exposed to 0.025, 0.05, 0.1 and 0.5 % aqueous extracts of green tea, black tea, unfermented and fermented rooibos for 24h. In vitro analysis of tea and the herbal infusion revealed the phenolic property and antioxidant capacity (FRAP) in the order Gt > Bt > Ur > Fr. Camellia sinensis and Aspalathus linearis revealed no significant effect on serum antioxidant capacity (p > 0.05) and lipid peroxidation (MDA) in the kidney or liver in both male and female rats and in the testes of the male rats (p > 0.05). In addition, the antioxidant levels were maintained in the testes, liver and kidneys in both the male and female rats. In the male rats, no significant alterations were observed in body weight gain, liver and reproductive organs weight, and serum testosterone (p > 0.05). Only, 5% green tea significantly increased testosterone level (p < 0.05). Seminiferous tubules displayed complete spermatogenesis with abundant sperm in the lumen in all treated groups. However, a significant decrease in diameter and germinal epithelial height of these tubules were observed (p < 0.05). In the epididymides, epithelial height of caput region showed a significant increase (p < 0.01), while the cauda region was increased by Camellia sinensis but decreased by Aspalathus linearis. Sperm concentration improved significantly by green tea and unfermented rooibos (p < 0.05), while black tea and fermented rooibos produced a non significant effect (p > 0.05). Sperm viability was enhanced in all treatment groups (p < 0.05). Furthermore, green tea, black tea and unfermented rooibos significantly improved the motility of rat sperm (p < 0.05); fermented rooibos tended to improve it (p > 0.05). In addition, green tea, black tea and fermented rooibos enhanced acrosome reaction (p < 0.05). Creatinine activity was significantly higher in rats treated with black tea, unfermented rooibos or fermented rooibos (p < 0.05), green tea tended to increase it (p > 0.05) reflecting the significant increased kidney weight in the treatment groups at high concentrations. Liver markers, ALT and AST, decreased significantly in all treated groups (p < 0.05), except in 5% fermented rooibos where a significant increase in AST level was observed (p < 0.01). In the female rats, the body weight gain, and reproductive organs weight was no affected (p > 0.05). However, 5% fermented rooibos reduced the ovarian weight (p < 0.05), while 5% unfermented rooibos significantly increased the uterine weight (p < 0.05). Liver weight increased significantly by black tea and unfermented rooibos (p < 0.05) while the kidney weight increased significantly by 5% black tea (p < 0.05). No significant effect was observed in the level of FSH produced, on the other hand, Camellia sinensis significantly lowered the level of LH (p < 0.05), while Aspalathus linearis had no effect (p > 0.05). Creatinine activity was enhanced significantly only by 5% fermented rooibos (p < 0.05). Liver markers, ALT and AST were reduced in most treated groups except in fermented rooibos where an increase was observed. In addition, histological sections revealed no obvious alteration in the ovaries, uteri, kidneys and liver of all treated female rats. Camellia sinensis and Aspalathus linearis significantly reduced the level of testosterone produced in TM3 Leydig cells under stimulated conditions in vitro (p< 0.05). Furthermore, both plants maintained the viability and morphology of the cells. However, at 0.5% of either plant extracts, a significant decrease in the viability (p < 0.05) and altered morphology of the TM3 Leydig cells was observed. In conclusion, Camellia sinensis and Aspalathus linearis significantly improved certain sperm function which might be attributed to their high level of antioxidant activity. However, the prolonged exposure of both plant extracts might result in subtle structural changes in the male reproductive system and impair kidney function. In addition, fermented rooibos at high concentration may also impair the functions of the liver. In vitro, both plants were shown to possess anti-androgenic property on TM3 Leydig cells. Furthermore, both Camellia sinensis and Aspalathus linearis may be classified as weak phytoestrogens due to the changes in the weight of the uterus and ovaries observed. / South Africa

Homocysteine (Hcy) is a sulfur containing amino acid and is a potent neurotoxin. It has been shown that elevated levels of Hcy, termed hyperhomocysteinemia, plays a role in the pathologies of Alzheimer’s disease (AD) and age-related cognitive decline. Hcy is a glutamate agonist, which causes in increase in Ca[superscript (2+)] influx via the activation of NMDA class of excitatory amino acid receptors, which results in neuronal cell death and apoptosis. Estrogen and progesterone are female hormones that are responsible for reproduction and maternal behaviour. However, in the last decade, it is evident that both female hormones have neuroprotective properties in many animal models of neurodegeneration. Collectively, both estrogen and progesterone reduce the consequences of the oxidative stress by enhancing the antioxidant defence mechanisms, reducing excitotoxicity by altering glutamate receptor activity and reducing the damage caused by lipid peroxidation. However, the mechanisms by which estrogen and progesterone provide such neuroprotection probably depend on the type and concentration of hormone present. Moreover, numerous studies have shown that hormone replacement therapy (HRT, estrogen and progestins) or estrogen-only replacement therapy (ERT) may prevent or delay the onset of AD and improve cognition for women with AD. Clinical trials have also shown that women taking HRT may modify the effects of Hcy levels on cognitive functioning. Oxidative stress increases in the aging brain and thus has a powerful effect on enhanced susceptibility to neurodegenerative disease. The detection and measurement of lipid peroxidation and superoxide anion radicals in the brain tissue supports the involvement of free radical reactions in neurotoxicity and in neurodegenerative disorders. The hippocampus is an important region of the brain responsible for the formation of memory. However, agents that induce stress in this area have harmful effects and could lead to dementia. This study aims to investigate and clarify the neuroprotective effects of estrogen and progesterone, using Hcy-induced neurodegenerative models. The initial studies demonstrate that estrogen and progesterone have the ability to scavenge potent free radicals. Histological studies undertaken reveal that both estrogen and progesterone protect against Hcy-induced neuronal cell death. In addition, immunohistochemical investigations show that Hcy-induced apoptosis in the hippocampus can be inhibited by both estrogen and progesterone. However, estrogen also acts at the NMDA receptor as an agonist, while progesterone blocks at the NMDA receptor. These mechanisms reduce the ability of Hcy to cause damage to neurons, since Hcy-induced neurotoxicity is dependent on the overstimulation of the NMDA receptor. SOD and GPx are important enzymatic antioxidants which can react with ROS and neutralize them before these inflict damage in the brain. Hcy can increase oxidative stress by inhibiting expression and function of these antioxidants. However, it has been shown that the antioxidant abilities of both estrogen and progesterone can up-regulate the activities of SOD and GPx. These results provide further evidence that estrogen and progesterone act as antioxidants and are free radical scavengers. The discovery of neuroprotective agents is becoming important as accumulating evidence indicates the protective role of both estrogen and progesterone in Hcy-induced neurodegeneration. Thus further work in clinical trials is needed to examine whether reducing Hcy levels with HRT can become the treatment of neurodegenerative disorders, such as Alzheimer’s disease.

Pantothenate (vitamin B5), which is the invariable metabolic precursor to coenzyme A, is synthesized from L-aspartate and alpha-ketoisovalerate in a converging four-step process in bacteria. Here, structural studies of two enzymes of pantothenate biosynthesis in Escherichia coli, L-aspartate-alpha-decarboxylase and ketopantoate hydroxymethyltransferase, are described. Ketopantoate hydroxymethyltransferase catalyzes the transfer of a hydroxymethyl group on to alpha-ketoisovalerate, assisted by the cofactor 5,10-methylene-5,6,7,8-tetrahydrofolate. In order to determine the mode of cofactor binding to the protein, ketopantoate hydroxymethyltransferase was crystallized in the presence of two 5,10-methylene-5,6,7,8-tetrahydrofolate analogues and alpha-ketoisovalerate. X-ray diffraction patterns, collected on the in-house X-ray diffraction data collection facility, extended to 4.0 Angstroem. Unit cell dimensions derived from these diffraction patterns indicate an asymmetric unit with one decameric enzyme. A detailed comparative structural analysis of the fold of ketopantoate hydroxymethyltransferase was carried out. Based on this investigation it was possible to assign the enzyme to the phosphoenolpyruvate/pyruvate enzyme superfamily. Furthermore, similarities in the mode of ligand binding to the catalytic magnesium, as well as differences in the mechanisms between the enzymes within this superfamily could be delineated. In common with a small, but widely distributed, group of mechanistically-related enzymes, L-aspartate-alpha-decarboxylase is translated as an inactive pro-enzyme, which self-processes at a specific site. In this process of intra-molecular protein maturation a covalently bound pyruvoyl cofactor is formed. A fast purification system for eight L-aspartate-alpha-decarboxylase mutants was established that allows production of large amounts of enzyme. In order to gain insights into the molecular mechanism of self-processing, crystallographic studies were carried out. Several of the purified mutants have been crystallized. X-ray diffraction data from glycine 24 to serine and serine 25 to threonine mutants were collected, to a maximum resolution of 1.26 Angstroem. The respective crystal structures were solved by molecular replacement. Along with the structures of an unprocessed, native precursor form of L-aspartate-alpha-decarboxylase and a serine 25 to alanine mutation, the structure models were refined and evaluated, and the models deposited in the Protein Data Bank. Analysis of these four structures together with four other L-aspartate-alpha-decarboxylase mutant structures revealed specific conformational constraints on the self-processing mechanism. Threonine 57 and a water molecule could be identified as catalytic elements, most likely essential for acid-base catalysis, and stabilization of the oxyoxazolidine intermediate in the self-processing reaction. A molecular mechanism for self-processing in L-aspartate-alpha-decarboxylase, largely based on the threonine 57 and a water molecule, is proposed. The differences in the structures of the cleavage site of the serine 25 to alanine and serine 25 to threonine mutants, relative to the structure of the unprocessed native precursor, suggest that molecular models of the cleavage site and mechanisms, based solely on serine to alanine and serine to threonine mutants, may lead to erroneous interpretations of the mechanism. On comparison with other self-processing systems, particularly, glycosylasparaginase, remarkable parallels in the structural features of the environment of the cleavage site were identified.