O emprego de cobertura por tela antigranizo em pomares de macieiras vem aumentando no Sul do Brasil. Porém, sabe-se pouco a respeito de seus possíveis efeitos sobre o microclima e, consequentemente, sobre o desenvolvimento das plantas, o rendimento e qualidade dos frutos. O objetivo deste trabalho foi avaliar alterações no microclima de pomar de macieiras sob tela antigranizo e seus efeitos sobre o desenvolvimento e a produção de macieiras na região de Vacaria, RS. O estudo foi conduzido em pomar comercial, cultivado sob tela antigranizo preta e em céu aberto, no município de Vacaria, RS, nos ciclos 2008/2009, 2009/2010 e 2010/2011. Foram feitas medições de radiação fotossinteticamente ativa (RFA), temperatura e umidade do ar, velocidade do vento e precipitação pluvial. Calculou-se a evapotranspiração de referência (ETo), o acúmulo de graus-dia e a distribuição de RFA no dossel. Foram feitas avaliações fenológicas, fenométricas, anatômicas e fisiológicas, bem como análises de qualidade e rendimento de frutos. A tela antigranizo reduziu em 32% a RFA incidente e reduziu em 39% a velocidade do vento. A qualidade de radiação não se alterou com a cobertura, mas variou entre estratos do dossel. A cobertura não alterou as temperaturas média, mínima e máxima, a pressão parcial de vapor, umidade absoluta e relativa do ar, a precipitação pluvial e ETo. O dossel sob tela interceptou 38% menos RFA que em céu aberto, porém, a eficiência de interceptação não diferiu entre ambientes. A máxima eficiência de interceptação de RFA ocorreu quando IAF foi de 1,5 sob tela e de 2,5 em céu aberto. A cobertura por tela promoveu aumento na estatura de plantas e prolongou o subperíodo entre a frutificação efetiva e a colheita, retardando a maturação dos frutos. No entanto, o número de folhas e o índice de área foliar não foram alterados pela cobertura. Quanto à anatomia e fisiologia das plantas, verificou-se a necessidade de estudos mais detalhados em parâmetros que expressam relações hídricas entre plantas e ambiente. Embora reduzindo a radiação solar incidente, a cobertura não alterou a razão entre sólidos solúveis totais e acidez titulável, a coloração, as características organolépticas de frutos e não reduziu o rendimento de maçãs ‘Royal Gala’ e ‘Fuji Suprema’. Portanto, o uso de tela antigranizo sobre pomares de macieira é uma alternativa importante para proteção de macieiras a precipitações de granizo, pois causa pequenas alterações no microclima e no crescimento das plantas, assegurando a produção dos frutos. / The use of hail net coverage in apple orchards has increased in southern Brazil. However, little is known about their possible effects on the microclimate and, consequently, on plant growth, crop yield, and fruit quality. The objective of this study was to evaluate microclimate alterations in apple orchards under hail net and its effects on the development and production of apple trees, in Vacaria, Brazil. The study was conducted in commercial orchards, grown under hail black net and in open sky, in the municipality of Vacaria, RS, during the 2008/2009, 2009/2010 and 2010/2011 vegetative cycles. Continuous measurements of photosynthetically active radiation (PAR), air temperature and humidity, wind speed and rainfall were performed. The reference evapotranspiration (ETo), accumulated degree-days and PAR distribution into the canopy were determined. Parameters of phenology, fenometry, leaf anatomy and physiology as well as analysis of quality and fruit yield were evaluated. The hail net reduced by 32% the incident PAR and also reduced by 39% the wind speed. The quality of solar radiation did not change with coverage, but varied between canopy strata. The coverage did not alter the average, minimum and maximum air temperature, the air vapor pressure and absolute humidity, as well as the rainfall and ETo. The covered canopy intercepted 38% less PAR than in open sky, while the efficiency of PAR interception did not differ between environments. The maximum efficiency of PAR interception occurred when LAI was 1.5 and 2.5 under hail net and in the open air, respectively. The hail coverage promoted an increase in plant height and prolonged the sub-period between fruit set and harvest, delaying the ripening of fruits. However, it did not affect the number of leaves and leaf area index. On the other hand, regarding the anatomy and physiology of plants, there is a need of further detailed studies on parameters that express water relationships between plants and environment. Although reducing the incident solar radiation, the coverage did not change the ratio between total soluble solids and tritable acidity, the fruit color and organoleptic characteristics and did not reduce yield of 'Royal Gala' and 'Fuji Suprema' apples. Therefore, the use of hail net coverage on apple orchards is an important alternative to protect plants against hail precipitations, since it causes small changes in microclimate and plant growth, ensuring production of fruits.

A preocupação com a qualidade ambiental aumentou significativamente nos últimos anos. Isso é evidente pela rígida legislação ambiental e pela mudança de comportamento da sociedade frente a este assunto. Nesse contexto os estabelecimentos de serviço de saúde estão sendo obrigados a se adequarem aos novos sistemas de gerenciamento de resíduos sólidos, oriundos das suas atividades, mas nada se comenta à respeito do efluente gerados por estes empreendimentos. Os problemas associados aos efluentes gerados nos centros de serviços de saúde tem sido motivo de preocupação devido ao desconhecimento do perigo potencialmente escondido neste. Na cidade de Porto Alegre as águas residuais provenientes dos hospitais não são tratadas, sendo transportadas por redes coletoras até o Lago Guaíba. Este é uma das principais fontes de abastecimento de parte da população desta cidade. Este trabalho apresenta como objetivo analisar as características básicas físico-químicas de efluentes hospitalares de quatro unidades de saúde da cidade de Porto Alegre – RS, comparando-os com a legislação vigente no que diz respeito a limites de descarte de efluentes. A amostragem proposta foi aplicada a quatro unidades paralelamente, sendo coletadas cinco amostras de cada unidade num período de dois anos. As amostragens foram compostas. Por fim, constatou-se que os efluentes oriundos de serviço de saúde, para a segurança, principalmente do Meio Ambiente, deverão ser previamente tratados antes de atingir a rede pública coletora.

Este trabalho avaliou o lançamento de efluentes líquidos de quatro hospitais, de diferentes especialidades médicas, no município de Porto Alegre – RS, Brasil. Foi realizada uma pesquisa previa, nas especialidades de Traumatologia, Pneumologia, Oncologia e Geral, a fim de obter dados referentes ao descarte dos respectivos efluentes. Após foram realizadas cinco amostragens de cada especialidade hospitalar durante um ano. Os parâmetros determinados seguiram a Portaria Nº 05/89 – SSMA que aprova a Norma Técnica SSMA Nº 01/89 – DMA, que dispõe sobre critérios e padrões de efluentes líquidos a serem observados por todas as fontes poluidoras que lançam seus efluentes nos corpos d’água interiores do Estado do Rio Grande do Sul. Dos trinta e cinco parâmetros avaliados em cada amostragem, para cada hospital, vinte e oito apresentaram, concentração dentro do limite de descarte determinado pela Portaria 05/89, e sete ultrapassaram os limites de concentração da mesma Legislação. O consumo médio de água e a geração de esgotos, relacionados ao número de leitos, aproximase com os valores apresentados nas referências bibliográficas, considerando que, o número de atendimentos influencia diretamente na geração de efluentes hospitalares. A relação entre os resultados de DBO5 e DQO, de todas as especialidades, indica semelhança aos efluentes domésticos. Os resultados das concentrações de DBO5, DQO, Nitrogênio Total, Fósforo Total, pH, Coliformes Fecais e Coliformes Totais, tratados estatisticamente, apresentam semelhanças entre as amostragens e as especialidades comprovando que não há diferenças significativas entre efluentes líquidos nas especialidades hospitalares estudadas.

Esta dissertação tem como objetivo geral fazer um levantamento toponímico das linhas, comunidades, bairros e ruas do município de São Marcos/RS, para relacionar a motivação toponímica com a realidade sociocultural de seus habitantes. O objetivo geral desdobra-se nos objetivos específicos, que atendem aos procedimentos metodológicos adotados, e que são os seguintes: revisar trabalhos sobre toponímia da Região de Colonização Italiana; fazer um inventário de nomes das linhas, comunidades, bairros e ruas do município de São Marcos de acordo com fontes oficiais; investigar nomes populares desses lugares; pesquisar a origem de alguns nomes oficiais e populares; investigar se os topônimos sofreram modificações ao longo do tempo. Além disso, objetiva-se também analisar padrões de motivação entre os topônimos investigados e relacioná-los com questões de identidade e cultura regional. Para a constituição do corpus foi feito um levantamento dos nomes das linhas, comunidades, bairros e ruas em mapas oficiais de São Marcos. A partir da análise do corpus verifica-se que na denominação de linhas, bairros e ruas há uma forte predominância de antropotopônimos masculinos e de origem italiana. No caso das ruas, há predominância de antropotopônimos que homenageiam pessoas comuns, diretamente ligadas à comunidade, mostrando o sentimento de valorização local e a construção de uma identidade regional. Já no caso das comunidades, predominam os hagiotopônimos, demonstrando a forte influência religiosa e devoção aos santos que os primeiros moradores, imigrantes italianos, passaram a seus descendentes. / The general objective of this dissertation is to do a toponymic survey of lines, communities, districts and streets of São Marcos/RS in order to relate the toponimic motivation with its inhabitants’ sociocultural reality. The general objective is opened up in the following specific objectives: to review work on Toponymy of the Region of Italian Colonization (RCI); to make an inventory of the names of lines, communities, districts and streets of São Marcos/RS according to official sources; to investigate popular place names; to research the origin of some official and popular names; to investigate whether the toponyms have suffered modification over time; to analyze patterns of motivation among the investigated toponyms, and relate them with regional cultural and regional identity issues. In order to compose the samples we did a survey of the names of lines, communities, districts and streets on official maps of São Marcos. From the analysis of the samples, it has been noticed that there is a higher predominance of masculine anthropotoponyms of Italian origin. With regard to streets, there is predominance of anthropotoponyms which honor ordinary people, directly related to the community, showing a feeling of local valuing and the construction of a regional identity. In the case of communities, there is a higher predominance of hagiotoponyms. This shows the religious influence and devotion to saints that the first inhabitants, Italian immigrants, passed to their descendents.

Orientadores: João Semir, Flavio Maes dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-03T06:30:00Z (GMT). No. of bitstreams: 1 Liesenfeld_MarcusViniciusAthaydes_M.pdf: 4255872 bytes, checksum: a1829189f385e73de5d8ec3c28c4ebcb (MD5) Previous issue date: 2003 / Resumo: O maior benefício que os animais frugívoros proporcionam às sementes é distribuí-Ias em sítios favoráveis à sua sobrevivência. Entretanto, poucos trabalhos relacionaram diretamente o destino das sementes pós-dispersão e a contribuição feita pelo dispersor através da avaliação do sítio de dispersão. A eficiência da dispersão pode ser determinada pela qualidade do sítio de dispersão da semente, o que, por sua vez, influencia diretamente a sobrevivência de sementes na pós-dispersão, bem como a sobrevivência das plântulas. O bugio-ruivo Alouatta guariba clamitans (PRIMATES - ATELlDAE) consome os frutos e defeca as sementes do caquizinho-do-mato Diospyros inconstans (ESENACEAE), uma espécie secundária tardia, presente nas matas de encosta e restinga de Porto Alegre - RS. O propósito do estudo foi avaliar a qualidade desse primata como dispersor, baseando-se no seu comportamento e na análise do destino, da sobrevivência e da germinação in situ de sementes ingeridas pelos macacos, comparando-as com sementes não ingeridas (ou seja, oriundas de frutos caídos). Para tanto, foram marcadas estações circulares (20 cm de diâmetro) com sementes ingeridas e não ingeridas pelos bugios, localizadas abaixo de três situações (tratamentos): a) árvore-mãe de D. inconstans; b) dormitório noturno dos macacos; c) porções de floresta secundária jovem. Um total de 100 estações contendo 1832 sementes foram monitoradas durante 314 dias, quando as sementes foram quantificadas dentro de seis categorias de destino: 1) predadas; 2) atacadas por fungos; 3) removidas (desaparecidas da estação); 4) presentes na estação, mas sem germinar; 5) germinadas e 6) plântulas mortas após germinar. A morte das sementes por insetos iniciou tão logo os frutos ou as sementes nas fezes chegavam ao solo. Em todos os tratamentos, sementes não dispersas pelos bugios foram mais predadas por insetos do que sementes dispersas. Adicionalmente ao processo de deslocar sementes das árvores-mãe para sítios favoráveis para germinação, as sementes dispersas pelo bugio-ruivo sobreviveram por mais tempo do que as sementes não dispersas. Portanto, conclui-se que A. g. clamitans é um efetivo e eficaz dispersor de D. inconstans, pois distribui viáveis as sementes desta espécie para vários locais da floresta em que habita, aumentando a sobrevivência destas apesar de não alterar a velocidade de germinação. Não obstante, A. g. clamitans colabora com o recrutamento de D. inconstans na floresta secundária jovem / Abstract: The main benefit frugivorous vertebrates provide to plants is the distribution of their seeds in sites favorable for survival. The dispersal efficiency may be determined by the quality of the dispersal site, which directly influences post-dispersal seed and seedling survival. However, very few studies have investigated the relations between disperser activity, quality of the post-dispersal seeds and dispersal site features. The brown howler monkey Alouatta guariba clamitans (ATELlDAE, bugio-ruivo) is known to consume and disperse the seeds of Diospyros inconstans (caquizinho-do-mato, ESENACEAE), a Iate secondary forest tree found in the slope and plain Iate secondary forests of Porto Alegre city, South Brazil. The aim of this study was to evaluate the quality of the dispersal services provide by brown howler monkey to D. inconstans comparing the fate, survival and in situ germination rate of seeds consumed and not-consumed by this primate. Plots (20 cm diameter) containing dispersed and non dispersed seeds were tagged and classified into three types, related to their position within the forest: under the parent-tree, under nocturnal A. g. clamitans sleeping sites and distributed within the forest (treatments). It was found a total of 1832 seeds, which were accompanied along 314 days, when they were classified into six categories: predated, attacked by fungi, removed, not-removed, germinated and dead seedlings. Seed predation by insects occurred as soon as the fruits (or seeds into feces) fell to the ground, and it was observed that, in ali treatments, non-dispersed seeds were more insect-predated than dispersed ones. Additionally to the occupation of favorable sites for germination, dispersed seeds presented higher survival rates when compared with non-dispersed ones, which indicates that A. g. clamitans is an efficient disperser of D. inconstans seeds. Despite some neutral effects (percent germination and germination rate), the dispersal of D. inconstans seeds by A. guariba contributes to the species recruitment in early secondary forests / Mestrado / Mestre em Ecologia

Nasopharyngeal cancer lies in the upper part of throat behind the nose and near the base of the skull called the nasopharynx. It is more commonly diagnosed in parts of Asia, particularly in the southern China. Five local edible plants from different families; namely curry leaf (Murraya koenigii), temu kunci (Boesenbergia rotunda), spring onion leaf (Allium cepa), mushroom bean (Phaseolus vulgaris) and bunga kantan (Phaeomeria imperialis) were macerated to obtain methanol, ethyl acetate and hexane crude extracts. Each crude extract was tested against nasopharyngeal carcinoma (HK-1) and normal nasopharyngeal epithelial (NP-69) cell lines. All crude extracts from temu kunci (Boesenbergia rotunda) were found to contain flavonoids, alkaloids and polyphenols. Both methanolic and hexane crude extracts were found to exhibit cytotoxic effects against HK-1 cells but non-toxic against NP-69 cell line. Of all the bioactive compounds previously extracted from B. Rotunda, we have selected four commercially available flavonoids and polyphenols to narrow down our search to one potential anticancer agent. These compounds were tested against HK-1 and NP-69 cell lines for cytotoxicity and it was found that cardamonin exhibits highest cytotoxic effect against HK-1 cells with IC50 of 22 μg/mL. Cardamonin, a naturally occurring chalcone from the rhizome of Boesenbergia rotunda (locally known as temu kunci) was found to induce apoptosis in human nasopharyngeal carcinoma (HK-1) cell line in vitro. It exhibits a significant cytotoxic effect against human nasopharyngeal carcinoma cell line without affecting normal immortalized nasopharyngeal epithelial cell line (NP-69) in MTT assay. Based on these results, HK-1 cell line was treated with IC50 22 μg/mL in time-dependent manner 24, 48 and 72 hrs to further investigate the mechanisms of apoptosis. Apoptotic cells induced by cardamonin were illustrated by change in cellular morphology, increase in G2/M phase population and DNA fragmentation. Furthermore, up-regulation of caspase-3 and caspase-8 activities substantiated the induction of apoptosis through caspase-dependent pathway. Cardamonin leads to a decrease in overproduction of reactive oxygen species (ROS), disruption in mitochondrial membrane potential and drop in intracellular ATP level in HK-1 cells. Present study also revealed up-regulation of pro-apoptotic protein, Bax and apoptotic signalling factor, cytochrome c resulting in down-regulation of anti-apoptotic protein, Bcl-2. There was no fold change in caspase-9 gene expression level suggesting that HK-1 cellular apoptosis occurred independent of caspase-9. Activation of caspase-3 was directly regulated by caspase-8 and does not require caspase-9. Current findings on the mode of actions of cardamonin suggested its potential application as an anticancer agent against nasopharyngeal carcinoma.

The discovery of antibiotics has played a significant role in raising public health standards and improving the outcomes for patients with bacterial infections. Unfortunately, drug discovery efforts have not kept pace with emergence and spread of antibiotic resistance. This project is part of a discovery programme designed to assess the metabolic potential of Actinoallomurus, a recently described genus within the Actinobacteria. The schedule of work included small-scale fermentations (from 200 strains) followed by bioactivity testing. The most promising positive samples were then subjected to a combination of bioassays with chemical analyses to determine the chemical identity of the active compounds, with the objective of finding novel antibiotics. The Results section is organized in four different but closely related chapters. These present Actinoallomurus as a potential new source for active metabolites. Firstly, by showing, in a sample of around 200 strains, over 40% inhibited antimicrobial growth in the conditions tested but also by adding to the elevated quantity of positive hits a high degree of diversity, with the major biosynthetic pathways being identified whether in the molecules screened or also in the genomes analysed. To illustrate not only the type of metabolites produced by Actinoallomurus, but also the multidisciplinary of Drug Discovery expeditions three chapters characterizing new compounds are presented followed by a genomic characterization of four Actinoallomurus Strains. These three chapters show how the delivery of new potential drug candidates demands an always broader set of diverse tools to be applied. While the three new molecules support not only the ability of Actinoallomurus to produce interesting active metabolites, but also the importance that a proper strain library plays in drug discovery, the genomic analyses predict, as for many other actinomycetes, an even brighter future, since the genetic potential for producing bioactive molecules surpasses the compounds that can be detected under routine cultivation conditions.

There is an acute clinical need for small-calibre (<6 mm) vascular grafts for surgery, but unlike their large counterparts they still fail in long-term clinical application. The failures of small diameter grafts are primarily due to the early formation of thrombosis and intimal hyperplasia. Dynamics of blood flow leading to wall shear rate and blood flow pattern and their effect on the endothelial cell proliferation along with other anomalies, have been identified as one of the major deciding factors for the efficiency of grafts. Research has showed that intimal hyperplasia and associated complications which leads to the failure of graft develop preferentially in regions where there is disturbed blood flow haemodynamics which leads to uneven shear stress and turbulence in the flow, followed by flow stagnancy in the periphery of the graft. On the basis of these findings and the established advantages of swirling physiological blood flow, a new graft design having a swirling flow inducer on the inner surface of the graft throughout the axis has been proposed. Initially, different swirling profiles have been analysed using final elemental analysis and compared with conventional or plain grafts. The numerical analysis has revealed that the proposed design could indeed produce the swirling blood flow with much better haemodynamics. These analyses have shown that compared to plain graft, in swirling graft, blood flow velocity near the vessel walls significantly enhanced with uniform distribution of shear stress and thus could theoretically enhance performance of the grafts by providing a "wash away" effect and prevent the plaque formation. Electrospinning has been used to fabricate the proposed design and prototype samples have been produced using polyvinyl alcohol (PVA) and gelatine. After cross linking, prototype grafts have been tested as per standard protocols and various tests such as; uniaxial tensile tests, bursting strength tests and suture retention test were carried out and results were evaluated and compared with the conventional grafts. Human coronary artery, endothelial cells (HCAEC) and human cardiac myocytes (HCM) were seeded on the helical and plain grafts using surface seeding technique. At various time intervals cell proliferation, viability and morphology were observed in the presence of static and circulating media and results were compared with their conventional counterpart kept under the same conditions. Results obtained showed considerable amount of difference in cell spreading and cell viability in the helical graft as compared to the conventional graft which provided the advantage edge. Also, in the case of helical graft more uniformly in arranged HCAEC were observed with elongated morphology. Pressure myography studies were performed on both grafts and after endothelization, the helical graft proved to be more reliable and capable of withstanding the pressure as compared to conventional counterparts. It is therefore suggested, that the electrospun helical graft designed and fabricated in this work may be an attractive candidate for use as a potential small diameter vascular graft for implantation. This is based on its ability to better regulate haemodynamics of blood flow and support endothelization, albeit in vivo studies are required to fully substantiate the in vitro results.

There has been a lot of interest on solid lipid nanoparticles (SLNs) as these colloidal submicron drug dosage forms present a promising frontier in drug delivery. It is possible to incorporate susceptible drugs such as protein intended for oral delivery. Here, we aim to develop an oral delivery system based on SLNs to deliver the peptide hormone, insulin using the double emulsion (W/O/W) solvent evaporation technique for formulating the SLNs. The choice of lipids was carefully selected to incorporate acceptability to biological milieu. The main purpose of the work was to formulate SLNs to achieve different localisation of insulin within the SLNs, based on the three hypothetical models proposed by Muller et al. (2000). Following that, the effect of this localisation on the propensity of the SLNs to be taken up by absorptive cells was investigated. SLNs was successfully fabricated to achieve two insulin localisation models, namely the solid solution model and the core-shell model with drug-enriched shell. The zeta potential measurements was used to indirectly indicate the appropriate insulin localisation model. The zeta potential of the unloaded SLNs, insulin-loaded SLNs and surface-adsorbed insulin SLNs were recorded as -51.7 ± 1 mV, -45.8 ± 1 mV and -40.8 ± 1 mV respectively. In vitro cell studies showed a notable difference in the Caco-2 cell lines when the cells were exposed to SLNs of the two different insulin localisation models. Thus, different effects seen on the Caco-2 cells suggests that the localisation of insulin within SLNs can potentially influence its uptake, stressing the importance of characterising drug localisation in nanoparticles, as this eventually affects drug bioavailability.

Successful delivery of pharmaceuticals orally requires a firm understanding of how dosage forms behave during their passage through the gastrointestinal (GI) tract. In this study, the GI transit time and absorption of amphotericin B (AmB) solid lipid nanoparticles (SLN) were investigated in rats, using paracetamol (PAR) and sulphapyridine (SP) as indirect markers. A high encapsulation efficiency of 91.2% was obtained for the AmB SLNs. The SLNs were exhaustively characterised with regards to size, zeta potential (ZP), viscosity, density, migration propensity within agarose gel, in vitro drug release and morphology, to ensure similar disposition in the GI tract after simultaneous oral administration. Freeze-drying did not significantly alter the size or ZP of the AmB SLNs, and in vitro drug release from fresh and freeze-dried SLNs were identical. AmB, PAR and sulphasalazine (SSZ) (the latter being the prodrug of SP) were individually formulated into SLNs using beeswax and theobroma oil as the lipid matrix. The z-averages, polydispersity indices and ZPs of the SLNs ranged from 206.5-224.8 nm, 0.161-0.218 and |61.90|-|71.90| mV, respectively. Gel electrophoresis studies indicated a similar movement propensity among the three SLNs as their migration distances were identical (22.2-22.4 mm) within agarose gel. Scanning electron and atomic force microscopy studies revealed that all three SLNs were spherical in morphology and with similar surface characteristics. The SLNs were assessed for changes in size and surface charge on exposure to simulated GI fluids using dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). On contact with the fluids, the particles had a slight increase in size due to ingress of the dissolution media. NTA results were found to be more beneficial than DLS as the latter was biased towards larger particles that were present possibly due to aggregation. After incubation in simulated gastric fluid followed by simulated intestinal fluid (mimicking gastric emptying), all the SLNs were found to be less than 350 nm in size and neutral in charge, which are optimal attributes for intestinal absorption. Time-of-flight secondary ion mass spectroscopic (ToF-SIMS) analyses revealed minimal drug amounts on the surfaces of the particles indicating that drug location was in the core of the SLNs. A developed and validated high-performance liquid chromatography (HPLC) method for simultaneous assay of the drugs in rat plasma using piroxicam as internal standard was found to be sensitive, accurate and precise, with drug recovery from plasma exceeding 92% in each case. A pilot GI transit study conducted in rats showed that the HPLC method was appropriate for the study. In the main study, the effects of food on the transit and absorption of the AmB SLNs were investigated. The presence of food slowed the transit of the SLNs in the GI tract. The gastric transit time of the AmB SLNs was estimated indirectly using PAR and was obtained as 1.71-2.25 hr. Caecal arrival time (CAT) of the AmB SLNs was estimated using SP detection in plasma as SSZ metabolism to produce SP occurs predominantly by the activity of colonic flora. In both fasted and fed states, CAT was 1.80-1.90 hr whereas transit time through the small intestine was 1.65-1.79 hr. A delayed rate of AmB absorption was observed in the fed state however, the extent of absorption was not affected by food. The percentage AmB absorption during the fasted state in the stomach, small intestine and colon were not significantly different from absorption within the respective regions in the fed state. In both states however, absorption was highest in the colon and appeared to be a summation of small intestinal absorption plus absorption proper within the colon. The study indicated that, AmB SLNs irrespective of food status were slowly but predominantly taken up via the lymphatic route and the small intestine was the most favourable site for their absorption. The data obtained indicate that it is possible to enhance the bioavailability of AmB through its incorporation into SLNs. Further enhancement of AmB bioavailability can be achieved through appropriate formulation interventions aimed at slowing transit of the SLNs in the small intestine. Finally, being a lipid-based system, the SLNs may have a potential to reduce the nephrotoxic effects of AmB.