Дисертації з теми "Substance P Physiological effects"

Unilateral exercise can produce certain contralateral strength effects. Deleterious events can be cross-transferred as well, as illustrated by a strict symmetry in some chronic inflammatory diseases. To date, knowledge on the effects of marked overuse of skeletal muscles is limited, and there is largely no information if unilateral overuse affects the contralateral muscles. In view of this, the present study was undertaken to test the hypothesis that unilateral muscle overuse causes alterations in tissue structure and the tachykinin system, with a focus on substance P (SP), not only in the exercised muscles, but also in the contralateral muscles. SP is a well-known neuromodulator that is known to be proinflammatory. An experimental rabbit model with unilateral muscle overuse of the soleus and gastrocnemius muscles caused by exercise via electrical muscle stimulation (E/EMS) was used. In total, 40 rabbits were randomly divided into seven groups of which two groups served as controls. The rabbits were anaesthetized and then set on a “kicking machine” to perform exercise via EMS for 2h every second day. Experimental periods for groups 1-3 were 1, 3 and 6w, respectively, whereas groups 4-6 were exercised for 1w but also subjected to injections in the peritendinous tissue with SP, NaCL, Captopril (C), an ACE inhibitor, and DL-Thiorphan (Th) which inhibits the activity of neural endopeptidase. One group was not subjected to the experiment at all. The day after the last session of E/EMS, the soleus muscle and the gastrocnemius muscle from both legs were collected for analysis. Alterations in muscle structure and the tachykinin system were analyzed with enzyme and immunohistochemical techniques, in situ hybridization and EIA methods. After 1w of E/EMS, focal areas of the exercised muscles contained a mild infiltration of inflammatory cells (myositis) and small morphological changes. After 3 and 6w of E/EMS, distinct myositis and muscle changes were bilaterally present in focal areas of both muscles. The structural changes, which mainly were observed in myositis areas, consisted of increased fiber size variability, split fibers, internal myonuclei, necrotic fibers, fibrosis, fat infiltration, and small fibers containing developmental MyHCs. Bilateral morphological changes, such as loss of axons, were also observed in nerves. In addition, expressions of tachykinin and the SP-preferred receptor, the neurokinin-1 (NK-1R), were bilaterally upregulated in nerve structures and blood vessel walls.  Infiltrating white blood cells exhibited tachykinin–like and NK-1R immunoreactivity. NK-1R immunoreactions were also found in necrotic and regenerating muscle fibers. The concentration of tachykinin (SP) was significantly increased in both soleus and gastrocnemius muscles after E/EMS. There was a significant correlation between the two sides in concentration of tachykinin and in the intensity of tachykinin-like immunoreaction in blood vessel walls. The muscle fiber size and capillary supply of fibers were bilaterally decreased after 3w of EMS. The myositis areas contained an increased number of vessels with a larger size than capillaries, while areas with increased amount of connective tissue contained a very low number of capillaries. A bilateral fiber type shift against a lower proportion of slow MyHCI fibers and higher proportion of fast MyHCII fibers was observed in both muscles. The local injections of C+Th and SP+C+Th led to marked structural changes in the muscle tissue and marked increased NK-1R and tachykinin-like immunoreactivity in the myositis areas and increased tachykinin concentration in the tissue. In conclusion, the repetitive unilateral muscle overuse caused by E/EMS led overtime to muscle injury and myositis. The affected areas contained both degenerative and regenerative alterations in the muscle tissue and nerves, and an upregulation of the tachykinin system. Most interestingly, the changes not only occurred in the exercised side, but also in the homologous contralateral muscles. The tachykinin system appears to be an important factor in the processes of crossover effects.

Thesis (MTech Biomedical Technology)--Cape Peninsula University of Cape Town, 2005<br>In clinical radiotherapy, experiments are performed to determine optimal conditions of the radiation prior to radiotherapy. These experiments focus on the relative biological effectivness(RBE) determination and are predominantly applied in high linear energy transfer (LET) radiations i.e. fast neutrons, as the RBE values for such radiations vary greatly. In general, the RBE of a certain radiation relative to a given reference radiation flCo gamma) varies widely with the energy, dose, dose rate, fractionation, type of tissue and end-point used. Experience with neutron therapy at iThemba LABS has shown that treatment with more fractions and lower doses per fraction may be beneficial for some patients. To calculate the iso-effective treatment dose needed, an appropriate alp ratio for early effects is needed. In this study, the repair of mouse jejunum was measured for split-dose irradiations to determine if a suitable alP ratio for neutrons could be estimated using the known value for gamma rays and the applicable RBE.. Crypt stem cell survival was measured 3.5 days after split-dose exposures to p(66)/Be neutrons and 6OCo gamma rays. Dose response curves for both treatment modalities and for both acute and fractionated exposures were constructed by counting crypts of Leiberkhiin at the base of the villi in haematoxylin and Eosin-stained sections of mouse jejunum. Using a RBE value of 1.64 and an alP ratio of 7Gy noted for tbe fractionated photon exposures, an alP ratio of 11.5 IV could be estimated for neutrons.

Currently, opioids are extensively used in clinical practices in order to treat pain in patients. However, prolonged administration of opioids are not feasible due to the development of side effects especially tolerance, constipation, addiction and dependence. Our drug design is mainly aimed to reduce opioid induce side effects such as development of tolerance. The first strategy examined involves design and synthesis of peptide based single molecules that have a mu agonist and delta agonist pharmacophore in combination with a COX2 inhibitory pharmacophore. A new molecule, 3-17 having good delta agonist activity, partial COX2 inhibitory activity and weak mu agonist activity was produced. Moreover, Investigation of the bioactivities of the synthesized ligands including 3-17 in terms of their ligand receptor interactions were probed using NMR conformational analysis along with docking analysis to the respective homology modeled mu and delta opioid receptors as well as the COX2 enzyme. As a further continuation of this work, instead of peptide based mu agonist and delta agonist type pharmacophore, the highly mu selective fentanyl pharmacophore was used in combination with a pyrazole based and a pyrazolone based COX pharmacophore. Based on the SAR study and docking analysis of synthesized ligands to the homology modeled mu opioid receptor, an ideal tolerant position without significant loss of mu opioid agonist activity for fentanyl were found. The second strategy involves design and synthesis of a peptide based single molecule that has a mu agonist and a delta antagonist pharmacophore in combination with a NK1 antagonist pharmacophore. A novel molecule (4-2) containing delta antagonist activity, weak mu agonist activity and NK1 antagonist activity was identified. Its homology modeled mu opioid receptor bound conformation was compared with that of reference ligands. Docking analysis of modified 4-2 to the homology modeled mu opioid receptor revealed that it can be further modified to obtain better mu agonist activity. 4-2 showed antinociception for 45 min period of time after injection in tail flick assay. In addition to studies that were directed to avoid tolerance development due to opioid administration, peptide based potential analgesics such as biphalin was modified by introducing more peptidomimetic character in order to enhance its blood brain barrier permeability and proteolytic stability. The novel molecule (6-7) was produced in this study and its antinociception lasted for 30 min period of time after injection in the tail flick assay.

Bibliography: leaves 180-199.<br>xvii, 199, [68] leaves, [1] leaf of plates : ill. ; 30 cm.<br>Primary aim was to determine whether levels of the endogenous peptide substance P (SP) would parallel and reflect the reported increased levels of the trophic agent nerve growth factor which is associated with the development of sympathetic hyperinnervation (and ultimately hypertension) in the genetic animal model for hypertension, the spontaneously hypertensive rat.<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Clinical and Experimental Pharmacology, 1995

Indiana University-Purdue University Indianapolis (IUPUI)<br>Background: Previous studies show that prazosin, an α1-adrenergic receptor antagonist, decreases alcohol drinking in animal models of alcohol use and dependence and in alcohol-dependent men. These studies extended previous findings by using a paradigm that allows for separate assessment of prazosin on motivation to seek versus consume ethanol or sucrose in selectively bred rats given acute or chronic prazosin treatment. Methods: Alcohol-preferring P rats were trained to complete an operant response that resulted in access to either 2% (Exp. 1) or 1% (Exp.2) sucrose or 10% ethanol. In Experiment 1, a 4-week consummatory testing phase consisted of rats bar-pressing to “pay” a specified amount up front to gain access to unlimited ethanol (or sucrose) for a 20-minute period. A 4-week appetitive testing phase examined how much the rats would bar-press for ethanol in an extinction session when no reinforcer could be obtained. In Experiment 2, during testing, the response requirement was dropped to a 1 and daily session cycles of drug (3 weeks/ 14 sessions from Tues to Fri) or vehicle (2 weeks/ 9 sessions from Tues to Fri) treatment were alternated per drug dose for a total of 3 drug doses (3 cycles) per rat. After each drug cycle, a single non-reinforced extinction session was conducted with no drug ‘on board’ and no reinforcer access. On test days, rats were given IP injections of either vehicle or one of three doses of prazosin (Exp 1: 0.5, 1.0, 1.5 mg/kg; Exp 2: 0.25, 0.5, 1.0 mg/kg; balanced design; -30 min). Results: In Experiment 1, prazosin significantly decreased ethanol-seeking at all doses tested. The highest dose decreased ethanol intake and increased the latency to first lever-press and first lick. Sucrose-seeking and intake were decreased by the same doses of prazosin. In Experiment 2, prazosin significantly decreased reinforcer-seeking at the lowest and highest doses while ethanol intake was not decreased by prazosin. Conversely, sucrose-seeking was decreased at the highest dose of prazosin tested while sucrose consumption was decreased by all doses. Latency to lever-press for sucrose was increased by the lowest dose of prazosin compared to vehicle. Conclusions: These findings extend previous research and indicate that prazosin decreases motivation to seek ethanol and sucrose. The specificity of prazosin on different behaviors and over different reinforcers suggests that these findings are not due to prazosin-induced motor-impairment or malaise. These data suggest that prazosin may work by decreasing the reinforcing properties of reinforcers in general.

Indiana University-Purdue University Indianapolis (IUPUI)<br>Research in the alcohol preferring (P) rat has indicated that peri-adolescent alcohol (EtOH) consumption enhances the acquisition of oral operant EtOH self-administration, inhibits the extinction of responding for EtOH, augments EtOH-seeking behaviors, and increases relative reward value of EtOH during adulthood. Experiment 1 was conducted to determine if these adult effects of peri-adolescent EtOH intake could be observed using an Intracranial Self-Administration (ICSA) model. It was hypothesized that an increased sensitivity to the rewarding actions of EtOH would be manifested in peri-adolescent-EtOH-exposed subjects compared to naive subjects when the opportunity to self-administer EtOH to the posterior ventral tegmental area (pVTA) is available in adulthood. The pVTA is a primary site for EtOH’s reinforcing and rewarding properties in the mesolimbic dopamine (DA) system. Experiment 2 was a dose-response examination of the effects of EtOH administered to the pVTA on downstream DA efflux in the nucleus accumbens shell (AcbSh) via a joint Microinjection-Microdialysis (MicroMicro) procedure. Male P rats were given 24-h free-choice exposure to 15% volume/volume EtOH from postnatal day (PD) 30 to PD 60, or remained experimentally naive, with ad lib food and water. By the end of the periadolescent exposure period, average consumption was 7.3 g/kg/day of EtOH. After PD 75, periadolescent-EtOH-exposed and naïve rats were either implanted with an injector guide cannula aimed at the right pVTA for ICSA (Experiment 1), or two cannulae, one aimed at the right pVTA (injector) and one at the ipsilateral AcbSh (microdialysis) for MicroMicro (Experiment 2). Following one week of recovery from surgery, ICSA subjects were placed in standard two-lever (active and inactive) operant chambers. Test sessions were 60 min in duration and occurred every other day for a total of 7 sessions. Rats were randomly assigned to one of 5 groups (n=4-9/group) that self-infused (FR1 schedule) either aCSF (vehicle, 0 mg%), 50, 75, 100, or 150 mg% EtOH during 4 sessions, aCSF only for sessions 5 and 6 (extinction), and the initial concentration again for session 7 (reinstatement). MicroMicro subjects received six days of recovery from surgery, probe implantation the day before testing, and then continuous microdialysis for DA with 15 min microdialysis samples collected before, during, and then two hrs after 10-min pulse microinjection of either aCSF (vehicle, 0 mg%), 50, 75, 100, or 150 mg% EtOH. Neither EtOH-exposed nor naive groups of P rats self-infused the aCSF or 50 mg% EtOH concentration. While the naive group did not self-infuse the 75 or 100 mg% EtOH concentrations, the peri-adolescent EtOH-exposed group of P rats did readily discriminate the active lever from the inactive lever at these concentrations. Both groups self-infused the 150 mg% EtOH concentration. Pulse microinjections of EtOH during the MicroMicro procedure revealed that 75 and 100 mg% concentrations of EtOH increased downstream DA in the AcbSh of EtOH-exposed, but not naïve, subjects. 150 mg% EtOH increased downstream DA in both adolescent treatment groups. Overall, the results indicate that consumption of EtOH by P rats during peri-adolescence increases the reinforcing properties of EtOH in the pVTA in adulthood. The results also indicate that there were differential effects of peri-adolescent EtOH exposure on DA efflux in the AcbSh. This provides evidence that peri-adolescent EtOH-exposure produces long-lasting alterations in neural circuitry involved in EtOH-reinforcement, during adulthood.

Traumatic brain injury (TBI) today remains a major health and social problem for both developed and developing countries. It is the leading cause of death and disability under the age of 40, and despite the significance of this public health problem, no effective therapy exists. While a number of factors have been shown to be associated with the development of irreversible tissue injury after TBI, the formation of oedema and opening of the blood brain barrier (BBB) have been shown to be of major significance to outcome. Oedema formation in the brain, when left uncontrolled, results in increased intracranial pressure that may lead to a decrease in brain tissue perfusion, localised hypoxia and ischemia, and ultimately tissue herniation and death. The mechanisms associated with the development of oedema are largely unclear, and accordingly, current therapies are generally ineffective, often resulting in dehydration, hypotension and renal problems. This thesis describes the characterisation of neurogenic inflammation in the development of post-traumatic brain oedema and functional deficits, and particularly the role of substance P (SP) in mediating their development, using rodent models of both focal and diffuse TBI. Results from this thesis demonstrate that increased SP immunoreactivity, particularly at the level of the vasculature, is a ubiquitous feature of TBI implying a potential role in the breakdown of the blood brain barrier (BBB) following TBI. This was confirmed through the use of the NK[subscript 1] receptor antagonists, which attenuated BBB and oedema formation as well as deleterious morphological events such as dark cell change and axonal injury. The NK[subscript 1] receptor antagonists also resulted in an associated improvement in both motor and cognitive deficits, as assessed using a battery of functional outcome tests. Possible mechanisms of action of the NK[subscript 1] receptor antagonist included effects on the BBB, SP release, intracellular free magnesium concentration and aquaporin-4 channels. Neuroprotection could be facilitated with administration of a non-lipid permeable NK[subscript 1] receptor antagonist in the immediate postinjury period, or up to 12 h after TBI with a lipid permeable NK[subscript 1] receptor antagonist, suggesting that this class of drugs have a clinically viable therapeutic window. We conclude that SP has a significant role in the secondary injury process following TBI and may offer a novel target for the development of interventional pharmacological strategies.<br>Thesis (Ph.D.)--School of Medical Sciences, 2006.

In experimentally exposed mice, the environmental contaminant 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) produces significant suppression of adaptive immune responses at low doses. However, the underlying biochemical and cellular mechanisms of TCDD-induced immunotoxicity have remained elusive since the identification of these effects nearly 30 years ago. Antigen-presenting cells (APC) constitute various populations of cells essential for the initiation and maintenance of adaptive immune responses, and represent a potential target of TCDD toxicity. Thus, the studies presented here address the ability of TCDD to directly affect APC. The underlying objectives of these studies focus on the investigation of molecular signaling pathways and cellular processes potentially affected by TCDD. In order to eliminate conflicting variables found in vivo, we used ex vivo and in vitro models to address these objectives. Initial studies investigated the status and behavior of the aryl hydrocarbon receptor (AhR), a transcription factor recognized as the principal mediator of TCDD-induced immunotoxic effects, in the two main APC populations, macrophages and dendritic cells (DC). The results demonstrated that both APC populations expressed AhR. However, TCDD induced binding of AhR to dioxin response elements only in macrophages, and not DC. Because TCDD has been shown to alter DC function and survival in vivo, the possibility that TCDD altered other signaling pathways was addressed. Specifically, activation of the transcription factor NF-kB/Rel, integral in DC generation and function, was found to be suppressed by TCDD. This suppression was apparently mediated by a physical association between the AhR and proteins of NF-kB/Rel. Additional studies demonstrated that TCDD enhances the maturation of DC and appears to sensitize DC to apoptosis. These data establish that TCDD directly affects DC on the molecular and cellular levels and support several potential mechanisms of TCDD-induced immunotoxicity.<br>Graduation date: 2002

Qin, Jing.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.<br>Includes bibliographical references (leaves 162-218).<br>Abstract also in Chinese.<br>Acknowledgment --- p.i<br>Abstract --- p.ii<br>摘要 --- p.iv<br>Table of Content --- p.vi<br>List of Figures --- p.x<br>List of Tables --- p.xv<br>Abbreviations --- p.xvii<br>Chapter Chapter 1 --- Introduction --- p.1<br>Chapter 1.1 --- Ganoderma spp --- p.1<br>Chapter 1.1.1 --- Introduction of Ganoderma spp --- p.1<br>Chapter 1.1.2 --- Bioactivities of Ganoderma spp --- p.3<br>Chapter 1.1.3 --- Endocrine system and breast cancer --- p.11<br>Chapter 1.1.3.1 --- Estrogen --- p.11<br>Chapter 1.1.3.2 --- Estrogen receptors --- p.12<br>Chapter 1.1.3.3 --- Estrogen responsive genes --- p.15<br>Chapter 1.1.3.3.1 --- pS2 --- p.15<br>Chapter 1.1.3.3.2 --- Progesterone receptor --- p.18<br>Chapter 1.1.3.4 --- Androgen --- p.21<br>Chapter 1.1.3.5 --- Androgen receptor --- p.23<br>Chapter 1.1.3.6 --- Androgen responsive gene --- p.24<br>Chapter 1.1.3.6.1 --- Transmembrane prostate androgen-induced RNA --- p.24<br>Chapter 1.1.3.6.2 --- Uridine diphosphate glucose dehydrogenase --- p.26<br>Chapter 1.1.3.7 --- Breast cancer --- p.26<br>Chapter 1.2 --- "Endocrine Disruption of p,p '-DDE" --- p.28<br>Chapter 1.2.1 --- Introduction of p´ةp '-DDE --- p.28<br>Chapter 1.2.2 --- "p,p '-DDE in environments" --- p.29<br>Chapter 1.2.3 --- "p,p '-DDE in human body" --- p.32<br>Chapter 1.2.4 --- "p,p '-DDE and reproductive system" --- p.33<br>Chapter 1.2.5 --- Endocrine disruptor --- p.35<br>Chapter 1.2.6 --- "Action mechanism of p,p '-DDE on endocrine system" --- p.37<br>Chapter 1.2.7 --- Apoptosis --- p.39<br>Chapter 1.3 --- Food therapy against endocrine disruption --- p.41<br>Chapter 1.3.1 --- Food therapy and functional food --- p.41<br>Chapter 1.3.2 --- Ganoderma as a Functional food --- p.47<br>Chapter 1.3.3 --- Cancer prevention by dietary agents --- p.47<br>Chapter 1.3.4 --- Hormone therapy --- p.48<br>Chapter 1.3.5 --- Hormone-related properties of Ganoderma spp --- p.50<br>Chapter 1.4 --- The aim of the study --- p.51<br>Chapter Chapter 2 --- Materials and Methods --- p.52<br>Chapter 2.1 --- Ganoderma samples --- p.52<br>Chapter 2.2 --- Artificial cultivation of Ganoderma spp --- p.54<br>Chapter 2.3 --- Molecular identification of Ganoderma spp --- p.55<br>Chapter 2.3.1 --- Extraction of genomic DNA --- p.55<br>Chapter 2.3.2 --- Gene-specific polymerase chain reaction (PCR) --- p.56<br>Chapter 2.3.3 --- Gel electrophoresis --- p.56<br>Chapter 2.3.4 --- Purification of PCR amplified product for sequencing --- p.57<br>Chapter 2.3.5 --- Cycle-sequencing --- p.57<br>Chapter 2.3.6 --- Sequencing --- p.58<br>Chapter 2.3.7 --- Sequence analysis --- p.58<br>Chapter 2.4 --- Chemical analyses of Ganoderma spp --- p.59<br>Chapter 2.4.1 --- Polysaccharide preparations --- p.59<br>Chapter 2.4.2 --- Terpene profile --- p.60<br>Chapter 2.4.3 --- Fatty acid profile --- p.60<br>Chapter 2.5 --- Anti-oxidation activities --- p.61<br>Chapter 2.5.1 --- Superoxide radical scavenging assay --- p.61<br>Chapter 2.5.2 --- DPPH radical scavenging assay --- p.62<br>Chapter 2.6 --- Anti-proliferation effect on human breast cancer cells --- p.62<br>Chapter 2.7 --- Hormone-like effects --- p.63<br>Chapter 2.7.1 --- E-screen test --- p.63<br>Chapter 2.7.2 --- In vitro estrogen receptors (ERs) competitor binding assays --- p.64<br>Chapter 2.7.3 --- "Recombinant yeast cell based ER-, AR- and PGR-responsible promoter assays" --- p.65<br>Chapter 2.7.3.1 --- Recombinant yeasts --- p.65<br>Chapter 2.7.3.2 --- Growth medium for recombinant yeasts --- p.66<br>Chapter 2.7.3.3 --- "ER, AR and PGR assays" --- p.67<br>Chapter 2.7.3.4 --- β-Galactosidase assay --- p.67<br>Chapter 2.7.4 --- Real time PCR --- p.68<br>Chapter 2.8 --- Flow cytometry --- p.71<br>Chapter 2.9 --- Comet assay --- p.71<br>Chapter 2.10 --- DNA microarray --- p.73<br>Chapter 2.10.1 --- Total RNA isolation --- p.73<br>Chapter 2.10.2 --- cDNA synthesis --- p.73<br>Chapter 2.10.3 --- Preparation of labelled cDNA --- p.74<br>Chapter 2.10.4 --- cDNA purification --- p.74<br>Chapter 2.10.5 --- Oligo GEArray hybridization --- p.75<br>Chapter 2.10.6 --- Chemiluminescent detection --- p.76<br>Chapter 2.10.7 --- Data analysis --- p.77<br>Chapter Chapter 3 --- Results --- p.78<br>Chapter 3.1 --- Analysis of Ganderma spp --- p.78<br>Chapter 3.1.1 --- Mycelia and fruiting bodies --- p.78<br>Chapter 3.1.2 --- Identification of Ganoderma spp --- p.79<br>Chapter 3.1.3 --- Chemical properties of samples --- p.80<br>Chapter 3.1.4 --- Anti-oxidation activities --- p.90<br>Chapter 3.1.5 --- Anti-proliferation effect on human breast cancer cells --- p.90<br>Chapter 3.1.6 --- Hormone-like bioactivities --- p.93<br>Chapter 3.1.6.1 --- E-screen test --- p.93<br>Chapter 3.1.6.2 --- In vitro estrogen receptors (ERs) competitor binding assays --- p.94<br>Chapter 3.1.6.3 --- "Recombinant yeast cell-based ER-, AR- and PGR-responsible promoter assays" --- p.95<br>Chapter 3.1.6.4 --- ER- and AR-pathway gene expression by real time PCR --- p.97<br>Chapter 3.2 --- "Action mechanism of p,p' -DDE" --- p.99<br>Chapter 3.2.1 --- E-screen --- p.99<br>Chapter 3.2.2 --- In vitro estrogen receptors (ERs) competitor binding assays --- p.101<br>Chapter 3.2.3 --- Recombinant yeast cell based ER- and AR-responsible promoter assays --- p.103<br>Chapter 3.2.4 --- ER- and AR-pathway gene expression by real time PCR --- p.106<br>Chapter 3.3 --- Ganoderma tsugae mycelia extract against p.p' -DDE --- p.109<br>Chapter 3.3.1 --- E-screen test --- p.109<br>Chapter 3.3.2 --- ER- and AR-pathway gene expression by real time PCR --- p.110<br>Chapter 3.3.3 --- Analysis of cell cycle --- p.112<br>Chapter 3.3.4 --- Analysis of DNA damage --- p.114<br>Chapter 3.3.5 --- Analysis of sub-G1 peak --- p.117<br>Chapter 3.3.6 --- DNA damage and apoptosis relative gene expression by real time PCR --- p.120<br>Chapter 3.3.7 --- DNA microarray --- p.121<br>Chapter Chapter 4 --- Discussion --- p.131<br>Chapter 4.1 --- Analysis of Ganoderma spp --- p.131<br>Chapter 4.2 --- Effects of p.p´ة-DDE --- p.144<br>Chapter 4.3 --- Protective effects of G. tsugae against p.p' -DDE --- p.151<br>Chapter 4.4 --- Further investigation --- p.159<br>Chapter 4.5 --- Conclusion --- p.160<br>References --- p.162

Whoonga is a relatively new addition into the drug market. The need for this study was prompted by the devastating effects this new arrival has had in the lives of young people addicted to it. The purpose of this study was to investigate the effects of whoonga on the learning of affected youth in Kwa-Dabeka Township. This study adopted a qualitative method and employed a phenomenological approach to explore the experiences of participants with regard to whoonga use and their learning. Data was collected through purposive sampling. Interviews were conducted, using semi-structured and unstructured questions with the help of an interview guide. Observations were also conducted to collect more data. This was done in the classroom during teaching and learning, as well as outside the classroom during recess. The study employed a social learning theoretical framework on the experiences of participants with regard to the use of whoonga. Four participants from one high school in Kwa-Dabeka Township were involved in the study. Themes that emerged from the study were that all the participants were totally ignorant of what they were getting themselves into before they started using whoonga. Peer pressure, coupled with curiosity made their decision to use whoonga easy. Challenges that participants face now on daily basis are far beyond their young age. The findings have indicated that learning is a situation of near impossibility for the participants. The findings have also depicted a picture of young people who are trapped in a vicious cycle of one of life‟s harshest living conditions in terms of their encounters with parents, school and the communities they come from. Despite their hopes for a brighter future one day, participants see no end in sight for their suffering at the hands of this unforgiving, destructive drug at this point in time.<br>Educational Studies<br>M. Ed. (Socio-Education)

Indiana University-Purdue University Indianapolis (IUPUI)<br>Drug-drug interactions (DDIs) refer to situations where one drug affects the pharmacokinetics or pharmacodynamics of another. DDIs represent a major cause of morbidity and mortality. A common adverse drug reaction (ADR) that can result from, or be exacerbated by DDIs is drug-induced myopathy. Identifying DDIs and understanding their underlying mechanisms is key to the prevention of undesirable effects of DDIs and to efforts to optimize therapeutic outcomes. This dissertation is dedicated to identification of clinically important myopathic DDIs and to elucidation of their underlying mechanisms. Using data mined from the published cytochrome P450 (CYP) drug interaction literature, 13,197 drug pairs were predicted to potentially interact by pairing a substrate and an inhibitor of a major CYP isoform in humans. Prescribing data for these drug pairs and their associations with myopathy were then examined in a large electronic medical record database. The analyses identified fifteen drug pairs as DDIs significantly associated with an increased risk of myopathy. These significant myopathic DDIs involved clinically important drugs including alprazolam, chloroquine, duloxetine, hydroxychloroquine, loratadine, omeprazole, promethazine, quetiapine, risperidone, ropinirole, trazodone and simvastatin. Data from in vitro experiments indicated that the interaction between quetiapine and chloroquine (risk ratio, RR, 2.17, p-value 5.29E-05) may result from the inhibitory effects of quetiapine on chloroquine metabolism by cytochrome P450s (CYPs). The in vitro data also suggested that the interaction between simvastatin and loratadine (RR 1.6, p-value 4.75E-07) may result from synergistic toxicity of simvastatin and desloratadine, the major metabolite of loratadine, to muscle cells, and from the inhibitory effect of simvastatin acid, the active metabolite of simvastatin, on the hepatic uptake of desloratadine via OATP1B1/1B3. Our data not only identified unknown myopathic DDIs of clinical consequence, but also shed light on their underlying pharmacokinetic and pharmacodynamic mechanisms. More importantly, our approach exemplified a new strategy for identification and investigation of DDIs, one that combined literature mining using bioinformatic algorithms, ADR detection using a pharmacoepidemiologic design, and mechanistic studies employing in vitro experimental models.