The effects of limited and infrequent drinking, and atropine administration on feed intake and utilization was investigated in South African indigenous goats. Sixteen goats with an average body weight of 29.1 kg were subjected to water restriction and deprivation with concurrent atropine administration. They were fed ad libitum with a mixture of lucerne (Medicago sativa) and eragrostis hay (Eragrostis curvula), blended with molasses. The diet contained 10.47% crude protein, 38% crude fibre and 17.5 MJ/kg gross energy. Fifteen goats were randomly divided into 3 groups and were watered ad Libitum, 50% of ad libitum and 30% of ad libitum water intake respectively (Trial 1). In trial 2, a group of 8 animals were deprived of water for 3 days while the other group had free access to water daily (phase1). During phase 2, another group of 8 were watered on the 5th day while others had water ad libitum. A subgroup of 4 goats each were injected with atropine in both phases. The results showed that these goats have high water efficiency. The limited and infrequent supply of water decreased feed intake but enhanced nutrient utilisation. The provision of water at the 50% ad libitum level or once in 3 days is economical and beneficial to goat production in water-scarce areas. There is a need for complimentary investigations using atropine at high doses to further elucidate the effects of this drug on the gastro-intestinal functions of ruminants. / Dissertation (MSc (Physiology))--University of Pretoria, 2007. / Anatomy and Physiology / unrestricted

Please read the abstract in the section 00front of this document / Thesis (PhD (Pharmacology))--University of Pretoria, 2005. / Pharmacology / unrestricted

No description available.

Les traitements anthelminthiques (AH) visant à maîtriser l’impact des strongles gastro-intestinaux (SGI) sur la croissance des jeunes bovins doivent être rationnalisés afin de préserver durablement leur efficacité. L’objectif de cette thèse a été de développer et d’évaluer des stratégies de traitement ciblé sélectif (TCS) basées sur la croissance chez les génisses laitières de première saison de pâturage afin de préserver des populations refuges de SGI, non exposées aux AH, et ainsi de retarder l’apparition de résistance. La relation croissance/parasitisme en fin de saison a tout d’abord été étudiée dans des environnements variés ce qui a permis d’appréhender des lots plus infestés et, à l’intérieur de ces lots, des individus plus fortement infestés. Un arbre de décision de traitement de rentrée a été ensuite proposé en combinant des indicateurs de conduite au pâturage pour identifier les groupes à risque et plusieurs seuils de GMQ pour identifier les animaux souffrant le plus du parasitisme. Une stratégie de TCS basée sur le GMQ moyen réalisé à mi- saison a été évaluée sur le terrain par comparaison avec un traitement collectif. Aucune différence significative, en termes de croissance et de parasitisme, n’a été observée à la rentrée entre le groupe TCS et le groupe traité collectivement. Enfin, les attitudes et les perceptions des vétérinaires vis-à-vis du contrôle des parasitoses digestives en élevage bovin laitier et notamment d’une gestion plus raisonnée des anthelminthiques, ont été évaluées. Les vétérinaires reconnaissent la nécessité d’appréhender les traitements AH de manière raisonnée mais identifient de nombreux freins relatifs au développement du conseil et à la disponibilité d’outils simples, fiables et peu couteux. Les résultats de cette thèse montrent qu’il est possible de cibler l’utilisation des AH chez les génisses laitières de première saison de pâturage en se basant sur des indicateurs individuels et de groupe simples d’emploi. / In first grazing season calves (FGSC), the anthelmintic (AH) treatments used to control the negative impact of gastrointestinal nematodes (GIN) on growth must be rationalized to preserve their long-term efficacy. The aim of this PhD thesis was to develop and assess targeted selective treatment (TST) strategies based on growth in FGSC, in order to preserve GIN populations in refugia i.e. not exposed to AH, and thus delay the emergence of AH resistance. Firstly, the relation growth/GIN infection at housing was demonstrated in different environments which allowed identifying groups, and within groups, the most infected animals. Then, a tree treatment decision at housing was proposed combing grazing management indicators to identify the groups at risk, and several average daily weight gain (ADWG) thresholds to identify, within groups, the animals suffering the most of infection. A TST strategy based on mid- season mean ADWG was assessed in field survey in comparison with whole group treatment (WGT). No significant difference, in terms of growth and GIN infection, was observed at housing between the TST and the WGT groups. Lastly, the veterinarians’ behaviors and perceptions about the control of GIN in dairy cattle farming, including a more rational AH management, were assessed. The veterinarians recognize the need to consider the sustainability of the AH treatment but identify serval obstacles as the development of advices and the availability of simple, reliable and cheap tools.The results of this thesis show that it is possible to target the use of AH in FGSC basing on individual and group indicators.

The human GI tract has evolved to simultaneously absorb nutrients and be the frontline in host defence. These seemingly mutually exclusive goals are achieved by a single cell thick epithelial barrier, and a complex resident immune system which lives in symbiosis with the intestinal microflora and is also able to rapidly respond to invading pathogens. An immunological balance is therefore required to permit tolerance to the normal intestinal microflora, but also prevent the dissemination of pathogenic micro-organisms to the rest of the host. Inappropriate immune responses in genetically susceptible individuals are the hallmark of human inflammatory bowel disease (IBD) and are thus targeting effector immune cells and their cytokines remains the mainstay of treatment. However despite vigorous efforts to delineate the genetic contribution to IBD disease susceptibility using large multinational cohorts, the majority of disease heritability remains unknown. Epigenetics describes heritable changes in chromatin that are not conferred by DNA sequence. These incorporate changes to histones, chromatin structure and DNA methylation, which confer changes to gene transcription and thus gene expression and cellular function. Methylbinding proteins (MBD) have the ability to bind to methylated DNA and recruit large chromatin remodeling complexes that underpin a variety of epigenetic modifications. Methyl- CpG-binding domain protein 2 (MBD2) is one such MBD that is required for appropriate innate (dendritic cell) and adaptive (T cell) immune function, though its role has not been investigated in the GI tract. We hypothesized that alterations in chromatin are central to the reprogramming of normal gene expression that occurs in disease states. By defining the phenotype of immune cells in the absence of MBDs we hope to understand the mechanisms of chromatin-dysregulation that lead to immune-mediated diseases such as IBD. We therefore aimed to assess the role of MBD2 in colon immune cells in the steady state and in murine models of GI tract inflammation, thereafter identifying the culprit cell types and genes responsible for any observed changes. We envisaged that investigating heritable, epigenetic changes in gene expression that are inherently more amenable to environmental manipulation than our DNA code, may provide novel insight to a poorly understood mechanism of disease predisposition. In addition identifying the cellular and gene targets of Mbd2 mediated changes to immune homeostasis that may provide exciting and novel approaches to therapeutic modulation of pathological inflammatory responses. In chapter 3 we assessed the expression of Mbd2/MBD2 in the murine/human GI tract. Consistent with existing mouse data, levels of Mbd2 mRNA increased between anatomical divisions of small (duodenum, ileum, terminal ileum) and large intestine (caecum, colon, rectum). In addition MBD2 mRNA was greater in the rectum versus ileum, with active IBD associated with lower rectal MBD2 mRNA compared to quiescent IBD controls. Thus we sought to understand the role of Mbd2 in the colon, where mRNA levels were the highest in the GI tract and where appropriate immune function is central to prevent damaging inflammation. To address these aims required the development of existing methods of cell surface marker expression analysis using flow cytometry techniques to simultaneously identify multiple innate and adaptive immune populations. Using naïve Mbd2 deficient mice (Mbd2-/-) we observed CD11b+ CD103+ DCs were significantly reduced in number in Mbd2 deficiency. To understand the role of Mbd2 in colonic inflammation we employed a mouse model of chemical (DSS) and infectious (T. gondii) colitis comparing Mbd2-/- and littermate controls (WT). Mbd2-/- were extremely sensitive to DSS and T. gondii mediated colonic inflammation, characterized by increased symptom score, weight loss and histological score of tissue inflammation (DSS) and increased antibody specific cytokine responses (T. gondii) in Mbd2 deficient animals. Flow cytometry analysis of colon LP cells in both infectious and chemical colitis revealed significant accumulation of monocytes and neutrophils in Mbd2-/-. Indeed monocytes and neutrophils were the principal myeloid sources of IL-1b and TNF in DSS colitis and the number of IL-1b/TNF+ monocytes/neutrophils was significantly greater in Mbd2-/-. Lastly we employed our colon LP isolation techniques to analyse immune populations in active and quiescent IBD and healthy controls, using endoscopically acquired biopsy samples. Analysis revealed that as in murine colitis, active human IBD is characterized by the accumulation of CD14High monocyte-like cells, with an associated increased ratio of macrophage:monocyte-like cells. In Chapter 4 we sought to understand the cellular sources of Mbd2 that may explain the predisposition of Mbd2-/- to colitis. Firstly we restricted Mbd2 deficiency to haematopoietic cells using grafting Mbd2-/- bone marrow (BM) into lethally irradiated WT mice. These animals treated with DSS displayed increased weight loss, symptom score, neutrophil accumulation and histopathology score compared to mice irradiated and grafted with WT BM. Given the accumulation of monocytes in Mbd2-/- DSS treated mice, and existing literature supporting a pathogenic role in this model, we then investigated the role of Mbd2 in monocyte function. Colon monocytes sorted from Mbd2-/- and WT DSS treated mice displayed similar expression for many pro-inflammatory genes (Il6, Il1a, Il1b, Tnf), but demonstrated significantly dysregulated expression for some others (Regb, Lyz1, Ido1, C4a). To investigate this in a more refined model, we lethally irradiated WT mice and repopulated them with a WT:Mbd2-/- BM mix. This enabled the analysis of WT and Mbd2-/- haematopoietic cells in the same animal. Colon WT and Mbd2-/- monocyte recruitment and cytokine production in DSS treated mixed BM chimeras was equivalent between genotypes suggesting that Mbd2 deficiency in monocytes alone did not explain the increased susceptibility of Mbd2-/- to DSS colitis. We then restricted Mbd2 deficiency to CD11c expressing cells, given the known role for Mbd2 in their function, and for CD11c+ cells in DSS, using a CD11cCreMbd2Fl/Fl system. DSS treated mice with Mbd2 deficient CD11c+ cells demonstrated increased weight loss, symptoms score, histolopathology score, monocyte and neutrophil colon accumulation compared to controls. To further explore the role of Mbd2 in colon CD11c+ cells, macrophage and DCs from DSS treated WT and Mbd2-/- mice were purified and their gene expression analysed. Mbd2-/- versus WT macrophages demonstrated significantly altered expression of both pro- (Il1a, C6, Ido1, Trem2) and antiinflammatory (Tgfbi, Retnla) pathways that we hypothesized was a method for attempted host control of excessive colon damage in Mbd2-/- mice. DC gene expression analysis was hampered by small sample size, but demonstrated a large number of small expression changes, including IL-12/IL-23 (Jak2) and autophagy (Lrrk2) pathways. Lastly levels of costimualtory molecules (CD40/CD80) were increased in Mbd2-/- but not CD11cΔMbd2 colon LP DCs/macrophages suggesting that non-CD11c+ cellular sources of Mbd2 were required to produce increased activation phenotype in these cells. Finally in Chapter 5 we explored the role for Mbd2 in non-haematopoietic cells, namely the colonic epithelium. Here we first developed a novel method for identifying and purifying these cells using flow cytometry. Mbd2 deficient colonic epithelium demonstrated increased expression of activation markers MHC II and LY6A/E in the steady state and in DSS / T. muris mediated colonic inflammation. Indeed FACS purified colon epithelial cells from naive and DSS treated, Mbd2-/- and WT mice revealed conserved dysregulated gene expression independent of inflammation: Both naïve and inflamed Mbd2 deficient epithelium displayed significantly increased expression of genes responsible for antigen processing/presentation (MHC I, MHC II, immunoproteasome) and decreased expression of genes involved in cell-cell adhesion (Cldn1, Cldn4). Lastly we investigated whether the observed differences in Mbd2-/- cell types conferred alterations in the makeup of the intestinal microflora. Interestingly independent of co-housing of Mbd2-/- and WT animals, Mbd2 deficiency consistently predicted the microbial composition, with increased levels of Clostridales and decreased levels of Parabacteroides bacteria. Collectively we have identified CD11c+ cells, monocytes and colon epithelial cells as key cell types for Mbd2 mediated changes in gene expression that affect mucosal immune responses. These data thus identify Mbd2 gene targets within these cell types as exciting new areas for investigation and therapeutic modulation to limit damaging GI tract inflammation.

Parkinson’s disease is a neurodegenerative disease resulting primarily from loss of dopaminergic innervation in the striatum subsequent to cell loss in the substantia nigra pars compacta. The abnormal accumulation of the normal pre-synaptic protein α-synuclein (αsyn) forms intraneuronal inclusions known as Lewy neurites and Lewy bodies. The origins of central Lewy pathology have been suggested to lie in the enteric nervous system, ascending through the vagus nerve to the dorsal motor nucleus of the vagus. To ascertain gastrointestinal regions most likely to be the source of central Lewy pathology, αsyn expression was evaluated in the neural elements of gastrointestinal regions receiving the densest vagal innervation. The vermiform appendix was found to have the densest αsyn-immunoreactive innervation in all layers of the gut wall. In addition, macrophages in the appendiceal mucosa were laden with αsyn within lysosomes, consistent with attempts to prevent the spread of disease or to correct synaptic dysfunction.

Orientadores: Jaime Amaya-Farfan, Fernanda de Pace / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T12:05:55Z (GMT). No. of bitstreams: 1 Roquetto_AlineRissetti_M.pdf: 2148135 bytes, checksum: 6a59bf58e9dbc6285574497bb9558141 (MD5) Previous issue date: 2015 / Resumo: A obesidade é um dos maiores problemas de saúde pública no mundo, sendo associada a diversas doenças metabólicas como inflamação, resistência insulínica, dislipidemia, esteatose hepática, entre outras. Recentemente, tem sido demonstrado que alterações nas proporções dos filos que compõem a microbiota intestinal repercutem negativamente sobre o metabolismo e processos fisiológicos do hospedeiro. A dieta moderna é apontada como um dos fatores capazes de modular as bactérias intestinais e desencadear respostas inflamatórias. Diante deste cenário e tendo conhecimento de que a própolis, resina produzida por abelhas que possui ação anti-inflamatória e antimicrobiana, a presente pesquisa teve como objetivo avaliar o efeito da suplementação da própolis em camundongos tratados com dieta hiperlipídica sobre a microbiota intestinal e biomarcadores inflamatórios. Quarenta camundongos da linhagem C57BL/6 foram divididos em 4 grupos (n=10) aleatoriamente: grupo controle ¿ dieta baseada na AIN-93G; grupo hiperlipídico (HF) ¿ dieta com 37% de gordura; e grupos HFP2 e HFP5 tratados com dieta hiperlipídica, seguida de suplementação com própolis 0,2% nas duas e cinco semanas que antecederam ao sacrifício respectivamente. Foram coletadas amostras de sangue e músculo para determinações bioquímicas e indicadores de inflamação, o conteúdo cecal foi extraído para sequenciamento do DNA da microbiota intestinal. Os resultados não mostraram diferenças no ganho de peso entre os grupos experimentais, mas o tratamento com própolis por 5 semanas foi efetivo em reverter a disbiose causada pela dieta HF, com relação aos filos Firmicutes, e Proteobacteria. Os níveis de lipopolissacarídeos (LPS) no soro, bem como a expressão de toll-like receptor-4 (TLR4) e de citocinas pró-inflamatórias no músculo foram reduzidos pelo tratamento prolongado com própolis. Além disso, esta intervenção melhorou os níveis séricos de glicose e triacilgliceróis. Estes resultados sugerem a possibilidade de que a própolis exerça ação benéfica modificando o microbioma que limita a permeabilização da parede intestinal, regulando a translocação de componentes bacterianos para a corrente sanguínea e, consequentemente, conduzindo a uma menor expressão de citocinas inflamatórias / Abstract: Obesity is a major world-wide public health problem and is associated with metabolic disorders as generalized inflammation, insulin resistance, dyslipidemia, hepatic steatosis, among others. Recently, it has been demonstrated that changes in the proportions of phyla that make up the gut microbiota have a profound effect on the metabolism and physiology of the host. The modern diet has been identified as one of the factors that modulate the intestinal bacteria and trigger inflammatory responses. Considering this state of affairs and knowing that propolis, a resin present in bee honey, has anti-inflammatory and anti-microbial action, the present study was designed to evaluate the effect of propolis supplementation on the intestinal microbiome and inflammatory biomarkers of mice pre-conditioned with a high-fat diet. Forty mice of the C57BL/6 strain were randomly divided into four groups (n = 10): control group ¿ diet based on the AIN 93-G; high-fat group ¿ diet with 37% fat; and two other groups treated with high-fat, HFP2 and HFP5, that were supplemented with 0.2% propolis during two and five weeks preceding sacrifice, respectively. Blood and muscle samples were collected for biochemical analyses and inflammation markers, the cecal contents were extracted for DNA sequencing of the intestinal microbiota¿s genome. The results showed no differences in weight gain among the experimental groups, but treatment with propolis for 5 weeks effectively reverted the dysbiosis caused by the HF diet with respect to the Firmicutes and Proteobacteria phyla. The levels of serum lipopolysaccharide (LPS), and Toll-like receptor-4 (TLR4) expression, and proinflammatory cytokines in muscle were reduced by the longer propolis treatment. In addition, this intervention improved serum glucose and serum triacylglycerol levels. The present results suggest that ingested propolis exerts its beneficial action, first modifying the intestinal microbiota, which limits intestinal wall permeability and controls the translocation of bacterial components into the bloodstream and thus averting inflammatory cytokine overexpression / Mestrado / Nutrição Experimental e de Alimentos / Mestra em Alimentos e Nutrição

Ample studies have shown that perturbation of metabolic phenotype is correlated with gene mutation and pathogenesis of colorectal cancer (CRC) and rheumatoid arthritis (RA). Mass spectrometry (MS)-based metabolomics as a powerful and stable approach is widely applied to bridge the gap from genotype/metabolites to phenotype. In CRC suffers, KRAS mutation accounts for 35%-45%. In previous study, SLC25A22 that encodes the mitochondrial glutamate transporter was found to be overexpressed in CRC tumor and thus to be essential for the proliferation of CRC cells harboring KRAS mutations. However, the role of SLC25A22 on metabolic regulation in KRAS-mutant CRC cells has not been comprehensively characterized. We performed non-targeted metabolomics, targeted metabolomics and isotope kinetic analysis of KRAS-mutant DLD1 cells with or without SLC25A22 knockdown using ultra-high performance liquid chromatography (UHPLC) coupled to Orbitrap MS and tandem MS (MS/MS). In global metabolomics analysis, 35 differentially regulated metabolites were identified, which were primarily involved in alanine, aspartate and glutamate metabolism, urea cycle and polyamine metabolism. Then targeted metabolomics analysis on intracellular metabolites, including tricarboxylic acid (TCA) cycle intermediates, amino acids and polyamines, was established by using LC-MS/MS coupled with an Amide BEH column. Targeted metabolomics analysis revealed that most TCA cycle intermediates, aspartate (Asp)-derived asparagine, alanine and ornithine (Orn)-derived polyamines were strongly down-regulated in SLC25A22 knockdown cells. Moreover, the targeted kinetic isotope analysis using [U-13C5]-glutamine as isotope tracer showed that most of the 13C-labeled TCA cycle intermediates were down-regulated in SLC25A22-silencing cells. Orn-derived polyamines were significantly decreased in SLC25A22 knockdown cells and culture medium. Meanwhile, accumulation of Asp in knockdown of GOT1 cells indicated that oxaloacetate (OAA) was majorly converted from Asp through GOT1. Exogenous addition of polyamines could significantly promote cell proliferation in DLD1 cells, highlighting their potential role as oncogenic metabolites that function downstream of SLC25A22-mediated glutamine metabolism. SLC25A22 acts as an essential metabolic regulator during CRC progression as promotes the synthesis of TCA cycle intermediates, Asp-derived amino acids and polyamines in KRAS-mutant CRC cells. Moreover, OAA and polyamine could promote KRAS-mutant CRC cell growth and survival. Rheumatoid arthritis (RA) is a chronic, inflammatory and symmetric autoimmune disease and a major cause of disability. However, there is insufficient pathological evidence in term of metabolic signatures of rheumatoid arthritis, especially the metabolic perturbation associated with gut microbiota (GM). Based on consistent criteria without special diet and therapeutic intervention to GM, we enrolled 50 RA patients and 50 healthy controls. On basis of the platform of UHPLC-MS and GC-MS, were performed for the non-targeted metabolomics to investigate alterations of endogenous metabolites in response to RA inflammation and interaction with GM. 32 and 34 significantly changed metabolites were identified in urine and serum of patients with RA, respectively. The altered metabolites were identified by HMDB, METLIN database or authentic standards, and mostly metabolites were attributed into tryptophan and phenylalanine metabolism, valine, leucine and isoleucine biosynthesis, aminoacyl-tRNA biosynthesis and citrate cycle. To obtain alterations of more components in tryptophan and phenylalanine metabolism, we developed and validated a targeted metabolomics method of 19 metabolites by using LC-QqQ MS. Combining the results of targeted metabolomics with global metabolomics, significantly up-regulated kynurenine (KYN), anthranilic acid (AA) and 5-hydroxylindoleacetic acid (HIAA) simultaneously in urine and serum was found to implicate the activation of tryptophan metabolism under the condition of RA, which acted pro-inflammatory roles in inflammation and was closely correlated with GM. IDO/TDO functioned as a pro-inflammation mediator was overexpressed in RA patients. Urinary kynurenic acid and serum serotonin that have impacts on anti-inflammation in immune system were down-regulated in RA patients. The levels of phenylacetic acid and phenyllactic acid serving as a pro-inflammatory and an anti-inflammatory agent, respectively, increased in serum of patients with RA. Moreover, certain essential amino acids (EAAs), and mostly conditional EAAs were decreased in RA patients, which have been reported to inhibit cell proliferation of immune cells. In particular, deficiency of branched chain amino acids (BCAAs, valine and isoleucine) was observed in serum of patients with RA, which may lead to muscle loss and cartilage damage. The specificity of all altered metabolites resulted from RA was considerably contributed through the GM-derived metabolites. The findings revealed that GM-modulated RA inflammation was mainly resulted from tryptophan and phenylalanine metabolism, and amino acid biosynthesis, which may provide more information for better understanding the RA mechanism.

Doctor Pharmaceuticae - DPharm / The popularity and increasing complexity of sustained release dosage forms has resulted in increased costs to the patient. One approach to achieve cheaper, yet effective, sustained release medication is through the simplification of production processes. Matrix tablets have been used to sustain the release of numerous drugs and are cheap to prepare. Since they are single-unit dosage forms, however, they display less predictable transit through the gastrointestinal tract. Hence, they provide less reliable blood levels of the drug in comparison with multi particulate dosage forms. Of the various types of multiparticulates available, pellets are popular for oral administration. A fairly recent innovation, in pelletization technology, is extrusion and spheronization. With this technique it is possible to produce pellets with a high degree of drug loading directly and rapidly. The drug loaded beads are usually coated for a sustained release effect. If one could omit the coating step, it would avoid many problems (thus reducing the number of quality control procedures required) and save chemicals, labour and capital for the purchase of additional equipment. The primary aim of this project was to investigate the preparation of non-coated, spheronized sustained release pellets, while a secondary aim was to prepare beads that can be compressed into sustained release tablets. A tablet can accommodate a larger mass and the compaction forces involved may enhance the sustained release effect. Several techniques were used in an attempt to sustain the release of drugs of different solubilities. In one series of formulations, a novel method was used to incorporate a binder consisting of ethylcellulose in ethanol. Using this technique, the release of Theophylline was sustained for approximately 8 hours. In other formulations, several materials were added to beads with the aim of forming sustained release matrixes. Only magnesium stearate was able to prolong the release of Acetaminophen and Theophylline for a reasonable time. In an attempt to explain why materials that were successfully used in sustained release matrix tablets were of very limited value in beads, an equation was developed to calculate the approximate distance between the retardant particles. Calculations using this equation revealed that the retardant particles were too far apart, within each bead, to expect consolidation to occur. The discrete retardant particles do not retard drug release effectively. Eudragit?-containing beads, which sustained the release of the drug to a small extent, were successfully compressed into tablets, both on their own and in combination with non pareil seeds. In each case, the sustained release effect was improved by compaction. In the case of the products manufactured with non pareil seeds, the tablets disintegrated rapidly to release the beads, thus ensuring that the advantages of multiparticulates were maintained. Because it was realised that a large amount of the matrix material could not be incorporated within the beads if a high dose drug was formulated with Avicel? PH 101, the idea of forming the matrix outside the beads was developed. Several materials were tried in an attempt to form a sustained release external matrix. Eudragit? RSPO prolonged the dissolution of Theophylline for more than four hours. Magnesium stearate was able to sustain the release of Acetaminophen and Theophylline appreciably. In the latter case, the dissolution, in water, of a standard adult dose of the drug was prolonged for more than 12 hours. However, the dissolution in an acidic medium was much faster. The described technique represents an advance in extrusion and spheronization technology. While beads containing Cutina? HR did not show promise as sustained release units, they compacted to form sustained release tablets of good appearance and acceptable strength. These tablets were considered to have been efficiently prepared because the constituent beads were easily manufactured and showed good flowability, and because a glidant and a lubricant were not required. The production of sustained release Indomethacin beads with a more steady release profile than the innovator's product has also been described in other experiments. The research described in this thesis represents progress towards the widespread commercial production of effective non-coated sustained release beads and may encourage further work towards this goal.

The scope of this masters thesis is the preparation of a model mucin system and its utilization as an artificial model of the native mucus system. The creation of this model system, according to several designed methods was a part of experimental part of the thesis. The preparation of mucin system comprised of physical and chemical methods of hydrogel formation, screening and characterisation of the various physical conditions of the mucin properties on its molecular level, and the preparation of sorbent with sorption surface containing mucin. Methods of light scattering, namely dynamic light scattering (DLS), used for mucin particles size change monitoring, and electroforetic light scattering (ELS), used for Zeta potential change monitoring, were used for the screening of the impact of physical factors on the properties of mucin.For the characterisation of impact of the temperature on changes in mucin sctructure was, apart from monitoring of light scattering, used also a diferential scanning calorimetry (DSC), which registered temperature value, at which mucin thermal denaturation occurs. In the next part of the thesis we subdued the created sorption surfaces to various physical-chemical analyses, which task is the characterisation and projection of surface and confirmation of mucin presence.Substancial part in monitoring and characterisation of changes in surface sctructure of sorption surface was accomplished by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscophy (SEM) was used for the final, more detailed, projection of the mucin enriched, sorbent surface structure. Suggested methods of mucin hydrogel, didnt prove sufficient results for the possibility of application of hydrogel as a artificial model of real mucus system, but the sorbent application was indicated as a suitable alternative and an instrument for the further mucin behaviour research and possibly subsequent bacterial adhesion, which represents the first step in the formation of the bacterial biofilm.