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Orientador: Sebastiao Roberto Taboga / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-09T02:18:22Z (GMT). No. of bitstreams: 1 Campos_SilvanaGiselePegorinde_D.pdf: 8120725 bytes, checksum: 6e1192220bc56007d359fcae3023e8d1 (MD5) Previous issue date: 2006 / Resumo: Há um grande interesse em melhor compreender a biologia da próstata devido à sua alta propensão em desenvolver lesões proliferativas, estando entre as mais comuns neoplasias que acometem o homem na atualidade. Entre os fatores de risco que contribuem para o aumento destas doenças destaca-se o envelhecimento, período em que ocorrem acentuados desequilíbrios hormonais. Vários grupos de pesquisa vêm tentando desenvolver, caracterizar e validar modelos roedores para análise do câncer de próstata sob diferentes aspectos e, modelos autóctones, têm desempenhado papel relevante nesse campo. Neste trabalho foi realizada a avaliação do comportamento biológico da próstata ventral do roedor gerbilo (Meriones unguiculatus) em fases distintas de seu desenvolvimento pós-natal. Em uma primeira etapa caracterizou-se através de análises morfológicas (estruturais e ultra-estruturais) e quantitativas os componentes celulares dos compartimentos epitelial e estromal, bem como o papel funcional de suas populações celulares na glândula. Para tanto foram utilizados gerbilos jovens, adultos e velhos. Considerando a próstata de animais jovens, constatou-se que nestes a glândula encontra-se estrutural e funcionalmente imatura. Já em animais adultos e velhos a atividade sintética está bem estabelecida e permanece estável nestas duas idades. Entretanto, a morfologia prostática em animais velhos apresentou-se diferenciada. Em uma mesma glândula puderam ser constatadas regiões funcionais com epitélio secretor semelhante aos adultos e, em outras, áreas completamente alteradas, dispondo de lesões histopatológicas. O comportamento prostático nas três fases do desenvolvimento analisadas foi diretamente influenciado pelos níveis de testosterona no soro, comprovando a importância desse andrógeno para homeostase e funcionalidade glandular. E, em animais velhos, o declínio de testosterona esteve associado a alterações proliferativas na glândula. Devido a essas constatações em uma segunda etapa, avaliou-se, exclusivamente, a próstata de animais velhos com o intuito de se caracterizar os principais tipos de lesões que podem acometê-la. As alterações mais freqüentes foram de origem epitelial, como as neoplasias intra-epiteliais (PIN), carcinomas microinvasivos e adenocarcinomas. O potencial invasivo das células anômalas pôde ser comprovado ultra-estruturalmente através da ruptura da membrana basal em alguns ácinos. No estroma, hiperplasia celular, quando constatada, esteve sempre associada a sítios de epitélio anômalo. Adicionalmente, uma maior deposição de fibrilas de colágeno (gerando fibrose estromal) foi encontrada em todos gerbilos velhos analisados. Parâmetros nucleares e nucleolares somente não foram efetivos para diagnosticar o potencial de severidade das alterações. Os índices de proliferação e morte celular, porém indicaram maior turnover celular à medida que alterações histopatológicas tornaram-se invasivas. A partir destes dados constatou-se que o gerbilo é um bom modelo para análise do comportamento prostático em diferentes fases do desenvolvimento pós-natal. Adicionalmente, o animal velho tem alta propensão em desenvolver alterações prostáticas espontâneas e estas podem auxiliar na melhor compreensão da evolução biológica do câncer prostático humano propriamente / Abstract: There is a great interest in understanding the prostate biology due to its high propensity in developing proliferative lesions. At the present time, this kind of illnes is one of the most common neoplasias which may damage men. Among the risk factors that contribute to the prostate cancer increase stands out aging, period when an accentuated hormonal unbalances happens. Several research groups are trying to develop, characterize and validate rodent models for analysis of the prostate cancer and, autochthonous models have been playing a relevant role in these aspects. In the present work, the biological behavior evaluation of the ventral prostate of gerbil rodent (Meriones unguiculatus) was accomplished in three different phases of postnatal development. Initially, the cellular components of epithelial and stromal compartments, as well as, the functional activity of those cellular populations in the gland were characterized through morphologic (structural and ultrastructural) and quantitative analyses. For this, young, adult and old gerbils were employed. Considering the prostate of young animals, it was verified that the prostate gland is structural and functionally immature. In adult and old animals the synthetic activity is well established and remained stable. However, in old animals, the prostatic morphology presented alterations. In a same gland it could be observed functional areas with a secretor epithelium similar to adults and regions completely modified, exhibiting histopathologic lesions. The prostatic behavior in the three phases of development was influenced directly by the serum testosterone levels, proving the importance of this androgen for glandular homeostasis and its functionality. In the old animals the testosterone decline was associated to the proliferative alterations presented in the gland. Because of these results, in a second stage of experiments, it was evaluated only the prostate of old animals with the purpose of characterizing the main types of lesions which may be develop in these gerbils. The most frequent changes noted were those originated in the epithelium, as the prostatic intraepithelial neoplasia (PIN), microinvasive carcinomas and adenocarcinomas. Ultrastructurally, the invasive potential of anomalous cells could be confirmed by the basement membrane disrupted noted in some acini. In the stroma, the cellular hiperplasia, when verified, it was always associated to the anomalous epithelium sites. Additionally, a larger deposition of collagen fibrils, which generates stromal fibrosis, it was found in all old gerbils analyzed. Nuclear and nucleolar parameters were not effective in diagnosing the severity potential of those alterations. The cellular proliferation and death indexes, however, indicated a larger cellular turnover according as the histhopatologic lesions become invasives. Concluding, these analyses allow confirming that the rodent gerbil is a good model for prostate behavior analysis in different phases of postnatal development. The old animal revealed a high propensity in developing spontaneous prostatic alterations and these changes may help to comprehend the natural course of the neoplasia's multistep and its biological behavior, contributing to a better understanding of the human prostate cancer / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

When given a choice between two foods of equal caloric value but different flavors, rats show a robust preference for that food whose flavor was previously associated with a higher calorie food. This finding suggests that rodents may identify food quality by sensory signals such as taste. The first portion of this thesis explores this flavor-calorie conditioning effect in other rodents, namely hamsters and gerbils. When hamsters were tested in the same paradigm as rats, the conditioning effect was not observed. This discrepancy may have resulted from the hamsters' ability to store food mash in their cheekpouches. Accordingly, hamsters were next presented with liquid diets which could not be cheekpouched. The conditioning effect was observed when different flavors were associated with different quality liquid diets. However, the effect was less robust than that discovered for rats. A second species, gerbils, did show robust conditioning effects. Thus, unlike rats and gerbils who show a robust flavor-calorie conditioning effect, hamsters are less likely to identify food quality by using taste cues. Once conditioned to detect caloric density by using flavor cues, hamsters and gerbils were placed on an 8-arm radial maze that consisted of four arms baited with high-calorie liquid and four arms baited with low-calorie liquid. The purpose of this second, part of the thesis research was to investigate the rodents' preference for food locations that contained food of varying qualities. Both species were expected to visit and drink first from the arm locations containing the higher calorie liquid. Although hamsters did not visit more high-calorie arm locations, they did drink from these arms more often. When visiting arm locations, hamsters appeared to use a circling strategy that began in the same arm each trial and consisted of visits to consecutive arms. Gerbils neither visited nor drank more often from the high-calorie arm locations. Gerbils also did not appear to use a circling strategy. Thus, when foraging on an 8-arm radial maze for food of varying quality, hamsters' use of a circling strategy prohibited them from first visiting high-calorie arms but not from preferentially drinking from these locations. Unlike hamsters, gerbils did not adopt a strategy to collect food rewards and were not selective about the food reward that was consumed. The foraging strategies of hamsters was further explored in the third part of the thesis. Hamsters were allowed to forage on an equally-baited 17-arm radial maze. Each arm location was baited with a sunflower seed. Once again, hamsters visited arm locations by using a circling strategy which consisted of visits to consecutive arms. However, on the larger maze hamsters did not begin each trial in the same arm location. In addition, hamsters that were placed on the same maze with 4 of the 17 baited arms blocked, given 13 arm location choices, removed from the maze while the blocks were also removed, and placed back on the maze to select 4 additional arm locations, did not preferentially select the previously blocked arms. Thus, hamsters whose response algorithm was disrupted did not show a memory-based strategy for collecting seeds from the maze. The major conclusions from this research are that 1.) Hamsters can learn to associate caloric density and flavor cues, but the learned effect is easily extinguished. 2.) This dietary information may be used when deciding what to eat but not where to forage. 3.) Hamsters appear to be harvesters who visit all foraging locations by adopting a response strategy. 4.) Gerbils can also learn to associate caloric density and flavor, and the learned effect is robust. 5.) Gerbils do not appear to use this information when deciding which foods to eat or where to forage. It will be interesting for future studies to see if rats use flavor-calorie information in foraging settings. / Arts, Faculty of / Psychology, Department of / Graduate

Toxocara canis (Werner, 1782) is the most common nematode parasite of dogs. In parts of the United States 21% of all dogs are infected with this intestinal roundworm (Ehrenford, 1957). In Provo, Utah, where 97 adult dogs were examined, 17. 5% harbored T. canis adults (Fox, personal communication).

The mammalian hearing organ, the cochlea, has a marvelous sensitivity and frequency resolution. Due to passive mechanical properties (e.g. mass, stiffness, damping), sound-induced traveling waves are formed on the basilar membrane (BM), which are longitudinally tuned to different frequencies. In a live cochlea, a phenomenon called cochlear amplification, derived from the mechano-electric transduction of the outer hair cells (OHCs), locally enhances the traveling wave and increases the frequency selectivity. My research during the PhD program was focused on studying the in-vivo mechanical and electrophysiological responses of the cochlea in animal models.In the first set of experiments, the intra-cochlear motion and the OHC-generated local cochlear microphonic (LCM) responses were measured in the base of the gerbil cochlea. We used optical coherence tomography (OCT) to measure the intra-cochlear motion and a tungsten micro-electrode to obtain the LCM responses. We explored the effect of the two types of sound stimuli, single and multi-tone stimuli, to the nonlinear behavior of the LCM and the intra-cochlear motion responses in two frequency bands: a frequency band in which cochlear responses show a nonlinear peak (the best frequency (BF) band) and a frequency range below the large peak (sub-BF band: f < ∼ 0.7 × BF). In the sub-BF band, BM motion had linear growth for both stimulus types, and the motion in the OHC region was mildly nonlinear for single tones, and relatively strongly nonlinear for multi-tones. Sub-BF, the nonlinear character of the LCM was similar to that of the OHC- region motion. In the BF band, the LCM and the intra-cochlear motions all possessed the BF peak nonlinearity. Coupling these observations with previous findings on phasing between OHC force and traveling wave motions, we proposed the following framework for cochlear nonlinearity: The BF-band nonlinearity is an amplifying nonlinearity, in which OHC forces input power into the traveling wave, allowing it to travel further apical to the region where it peaks. The sub-BF nonlinearity is a non- amplifying nonlinearity; it represents OHC electromotility, and saturates due to OHC current saturation, but the OHC forces do not possess the proper phasing to feed power into the traveling wave. In the second set of experiments, we repeated the cochlear measurements as in the first project in the base of guinea pig cochlea. The goal was to compare the degree of nonlinearity and amplification in the LCM and intra-cochlear responses between gerbil and guinea pig. The experimental condition and method were similar to the gerbil study. In the BF band, our observations were similar to our previous measurements in gerbil: a nonlinear peak in LCM responses and in intra- cochlear displacements, and higher motion in the OHC region than the BM. Sub-BF, the responses in the two species were different. In both species the BM motion responses in the sub-BF band was linear and LCM was nonlinear. Sub-BF in the OHC-region, nonlinearity was only observed in a subset of healthy guinea pig cochleae while in gerbil, robust nonlinearity was observed in all healthy cochleae. The differences suggest that gerbils and guinea pigs may employ different mech- anisms for to achieve frequency selectivity. However, it cannot be ruled out that the differences are due to technical measurement differences across the species.

Studies using Mongolian gerbils found that during a primary infection with Giardia lamblia trophozoites, disaccharidase activities were decreased from day 10 post-infection (p.i.) until well past elimination of the parasite. However, during a challenge infection, enzyme deficiencies were short-lived. A challenge with a soluble extract of G. lamblia trophozoites also resulted in reductions in disaccharidase activity. The degree of these reductions in enzyme activity was dependent on the extract dose. Gel filtration of the trophozoite crude extract resulted in fractions F1, F2, and F3. However, only a challenge with F1 led to disaccharidase deficiencies. Further separation of F1 resulted in fractions F1a and F1b. Impairments of enzyme activity were obtained only in gerbils challenged with F1b. Protein analysis of F1b revealed several high and low molecular weight bands. When gerbils previously exposed to G. lamblia were challenged with an extract of Entamoeba histolytica trophozoites, disaccharidase activities remained comparable to controls. Moreover, enzyme levels in gerbils challenged with excretory/secretory G. lumblia products were affected in a manner which was inconsistent with the live parasitic challenge. Results suggest that the disaccharidase deficiencies in giardiasis are parasite-specific and are induced by a heat-stable constituent(s) of fraction F1b, possibly through an immune response to an antigenic component of this parasite fraction.

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