Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 115-146) Also available in print.

Thesis (M. Med. Sc.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--Lehigh University, 1998. / Includes vita. Bibliography: leaves 51-64.

Proefschrift Maastricht. / Met lit. opg. - Met samenvattingen in het Nederlands en Turks.

Orientadores: Luis Antonio Violin Dias Pereira, Luis Guillermo Bahamondes / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-06T16:12:03Z (GMT). No. of bitstreams: 1 Santis_LucianaHelenade_M.pdf: 1888365 bytes, checksum: c15bc77fd1c517ee962df896bde92224 (MD5) Previous issue date: 2006 / Resumo: O espermatozóide é uma célula altamente especializada, uma vez que apresenta diferenciações morfofisiológicas que garantem o sucesso da fecundação. Com o objetivo de adquirir a capacidade de fecundação precisam passar por três processos seqüenciais, maturação epididimária, capacitação e reação acrossômica (RA). A capacitação é um processo que acontece no trato reprodutor feminino e define-se como uma mudança bioquímica na membrana plasmática do espermatozóide, sendo a presença de progesterona e o aumento na concentração intracelular do cálcio ('Ca POT +2¿) eventos característicos e obrigatórios para a posterior RA. O levonogestrel (LNG) é um progestágeno sintético, semelhante a progesterona, o qual tem sido usado como contraceptivo feminino, seja na contracepção de emergência (CE), nas pílulas contraceptivas combinadas ou com o dispositivo intra-uterino (DIU). Entretanto, na literatura não há dados que relacionem a eficácia contraceptiva do lenovogestrel com possíveis efeitos deste hormônio sobre os espermatozóides humanos. Assim, com o objetivo de adicionar dados a respeito do mecanismo de ação contraceptiva do LNG, este estudo teve como objetivo avaliar o efeito de 5 concentrações de LNG, comparáveis as concentrações encontradas no plasma sanguíneo de mulheres, após a ingestão de LNG sob a forma de (CE) com a concentração intracelular do cálcio em espermatozóides capacitados de homens férteis. Um total de 24 amostras de sêmen, provenientes de 4 homens férteis foram avaliadas. Os espermatozóides foram selecionados através de um gradiente de Percoll, e foram submetidas a um período de capacitação. Às amostras foi adicionado o corante Fura2/AM e a seguir estas foram expostas às concentrações de 8, 10, 14, 1.000 e 10.000 ng/mL de LNG e a dois controles, um positivo e outro negativo, sendo respectivamente a progesterona (32 'mu' M = 11.000 ng/mL) e a meio de cultivo human tubal fluid (HTF). A seguir as amostras foram avaliadas através da espectrofotometria de fluorescência, com exitação de 340 nm e emissão de 510 nm. A taxa de fluorescência foi convertida em medidas de concentração intracelular de cálcio ([('Ca POT 2+¿]i), utilizando a equação de Grynkiewicz et al. (1985), a qual demonstrou que as concentrações de 8, 10, 14 e 1.000 ng/mL de LNG foram capazes de induzir um aumento na [('Ca POT 2+¿]i significativamente maior quando comparados ao obtido com HTF, e significativamente menor que ao obtido com progesterona (o indutor natural), excetuando-se a concentração de 10.000 ng/ml (32 'mu' M) de LNG, a qual foi estatisticamente similar que a progesterona 11.000 ng/ml (32 'mu' M). Assim, é possível sugerir que o LNG in vitro, em baixas concentrações, aumente a [('Ca POT 2+¿]i nos espermatozóides. No entanto, este mecanismo, de maneira isolada, não deva ser o responsável pela indução da RA. Entretanto a [('Ca POT 2+¿]i obtida através de altas concentrações de LNG (10.000 ng/ml) pode ser sim, um possível mecanismo de ação do LNG como droga contraceptiva / Abstract: The spermatozoa is a highly specialized cell because it contains morfophysiological modifications that guarantees fecundation success. Spermatozoa must undergo three sequential changes before they acquire their fertilizing capacity: maturation in epididymis, capacitation and acrosome reaction (RA). Capacitation is a process that takes place in the female reproductive tract and is defined as a biochemical modification on the spermatozoa plasmatic membrane. The presence of progesterone (P) and the intracellular calcium concentration increase inside the spermatozoa are typical and obligatory events in the capacitation stage for further RA. Levonogestrel (LNG) is a synthetic progestin, similar to P, which has being used as a female contraceptive in several manners, among them they are: emergency contraception (EC), contraceptive pills combine and with the intrauterine system (IUS). Nevertheless, there are no available data or the scientific literature that correlate LNG contraceptive efficacy with possible effects of the hormones over human spermatozoa. Therefore, to add data over the contraceptive action mechanism of LNG, the aim of this study was to evaluate the effect of 5 concentrations of LNG somes comparable to the levels found in serum following ingestion of LNG as EC on the calcium intracellular concentration (['Ca POT 2+¿]i) rates of capacitated spermatozoa of fertile men. A total of 24 semen samples from 4 fertile men were evaluated. The spermatozoa were selected by Percoll gradient, following incubation with human tubal fluid medium supplemented with bovine serum albumin (HTF/BSA) under capacitating conditions. The sperm suspensions were incubated with Fura2/AM Subsequently the cells were exposed to the following concentration of LNG: 8, 10, 14, 1,000 and 10,000 ng/mL, and two controls (positive and negative). The positive control was P (32 'mu' M=11,000 ng/ml) and the negative one was medium (HTF). Cells were transferred to a quartz cuvette to make the reading in the spectrofluorometer at 340 nm excitation with emission at 510nm. Fluorescence measurements were converted to ['Ca POT 2+¿]i by the equation of Grynkiewicz et al. (1985). The Grynkiewicz equation shown that LNG concentration of 8, 10, 14, and 1,000 ng/mL were able to induce increase in the ['Ca POT 2+¿]i with significantly higher values, when compared with the rate obtained with HTF medium ( as a negative control), and significantly lower than the rate obtained with natural P (as a positive control). However, the exception was the LNG concentration of 10,000 ng/mL (32 'mu' M) in which values of ['Ca POT 2+¿]i were similar to those observed with P at a concentration of 11,000 ng/mL (32 'mu' M). In conclusion, it is possible to suggest that although LNG in vitro, in low concentration, increase the ['Ca POT 2+¿]i in the spermatozoids. Despite the fact that this mechanism is not the only responsible for the RA induction the calcium obtained through high concentration of LNG (10,000 ng/ml) might have a contraceptive action in the spermatozoa / Mestrado / Histologia / Mestre em Biologia Celular e Estrutural

M.Sc. (Zoology) / Milt and blood samples of Aarbus aeneus were collected during November in order to perform chemical analyses of the blood and seminal plasma. Physical analyses were also carried out on milt. Throughout the year testes were collected in order to determine the stages of testicular development. This was done by means of histological analyses. The sperm counts averaged 8,41 x 10-3 cells rom while the spermatocrit value varied between 44% and 82% (average of 61,9%). All the milt samples collected were white in colour showing a high viscosity. Sperm motility gradually declined after activation and stopped after 82,5 seconds. Chemical values of the components tested in the blood plasma were statistically compared to those in the seminal plasma and no statistically significant differences were recorded between sodium, potassium, chloride, calcium, magnesium, glucose, total lipid, total proteien concentrations, osmolality and pH. The only component where a difference in concentration occured was fructose (30% probability). Sodium, calcium, magnesium, glucose, fructose, total lipid and total proteien concentrations in the blood plasma were significantly lower than the corresponding concentrations in the seminal plasma. In contrast the potassium concentration were higher in the seminal plasma. The pH of the seminal plasma (8,63) was alkaline while a pH of 7,5 was recorded for blood plasma. In the two lobe testis of Barbus aeneus semen is collected with seminiferous ducts into the vas deferens which together with the blood vessels are housed within a hilus. The testis is surrounded by a tunica albugenea and the seminiferous lobules are filled with cysts. The testis of the smallmouth yellowfish appears to be lobular and sperm are deposited into lumens which exist between the cysts. During the resting phase the interstitial tissue is very difficult to distinguish and is seen as a thin layer of cells between the lobules seperating them from one another...

This thesis is a systematic description of normal and abnormal dog spermatozoa by means of bright field light and transmission electron microscopy, and an investigation into the effect that abnormal sperm have on canine fertility. A total of 101 ejaculates were collected from 88 dogs, of 34 different breeds. Sperm samples were examined macroscopically for volume, colour, consistency, and pH. Microscopic evaluation of sperm motility was conducted on all samples. Morphological evaluation using light microscopy was conducted on 71 of the samples. Samples from 10 of the dogs were examined ultrastructurally. A novel classification for abnormal dog sperm is presented. Abnormal sperm were classified into one of the following groups: Acrosomal defects, head defects, midpiece defects, tail defects and other abnormalities. Abnormalities were further sub-divided into major and minor defects. The most common abnormalities encountered were major sperm head defects. The abnormalities are compared with those described for other species, in particular the bull and man. The association between the percentage abnormal sperm in the ejaculate and the fertility of the dog was statistically evaluated. On this basis, the dogs were divided into normal and sub-normal groups. The percentage normal morphology below which fertility was adversely affected was found to be sixty percent. The fertility of dogs with greater than or equal to 60 percent normal morphology was 61 percent, while the fertility of dogs with · less than 60 percent normal morphology was 13 percent. There was no statistical difference between the ages of the dogs in the two groups; from this it was concluded that sub-fertility may affect a dog at any age. A means of evaluating dogs for reproductive potential is discussed.

No description available.

No description available.

Call number: LD2668 .T4 1964 C288 / Master of Science