1,721,234 research outputs found
Electron microscopy in the study of human sperm pathologies
No full textThe aim of this study is to underline the role of transmission and scanning electron microscopy analysis in the diagnosis of
human sperm pathologies. Among the possible causes of male infertility, defects of sperm morphology represent an
important factor that may explain decreased fertilizing potential of sperm. Electron microscopy allowed us to identify
systematic sperm defects that affect the vast majority of sperm in a semen sample and non-systematic sperm defects, a
heterogeneous combination of randomly distributed alterations affecting the head and the tail organelles in a varied
percentage of ejaculated sperm. Correct diagnosis of specific altered sperm phenotypes is important for the advancement
of new therapies for treating male factor infertility and for the choice and outcome of assisted reproduction techniques
Sperm morphology and aneuploidies: defects of supposed genetic origin
No full textAs individuals with genetic sperm defects are intracytoplasmic sperm injection candidates, the study of the chromosomal constitution of their spermatozoa is of great interest. This study is a review of the current literature concerning fluorescence in situ hybridisation studies in spermatozoa with genetic sperm defect as 'round head', 'dysplasia of fibrous sheath' (DFS), 'primary ciliary dyskinesia' (PCD), the 'detached tail' and the 'absence of fibrous sheath'. Regarding sperm head defects, elevated XY disomy and diplodies were detected. Genetic defects affecting the sperm tail seemed to have a different correlation with chromosome meiotic segregation. Only chromosome 18, among the autosomes, was studied and the percentage of frequency of disomy was generally within the normal range. In the more frequently studied defect, DFS, the alterations in gonosome disomy and diploidy were recorded by different groups. Regarding PCD defects, elevated frequencies of disomy of sex chromosomes and diploidy were observed, whereas the absence of the fibrous sheath and the detached tail did not show any meiotic disturbance. The problem of genetic sperm defects should be seriously considered when these sperm are used for assisted reproduction, owing to the high risk of transmission of chromosomal imbalance and of mutations that could cause genetic sperm defects in offspring
Ultrastructural and Aneuploidy Studies in Sperm from Patients with History of Consanguinity
No full textThe data on the role of consanguinity in male infertility are scarce. The presence of systematic sperm defects in
consanguineous respect to non-consanguineous population was demonstrated. Systematic defects are characterized by a
specific alteration present in sperm for the whole life of the carrier.
This study was aimed at exploring the sperm quality in selected infertile consanguineous patients (group 3) with nonsystematic
sperm defects, compared with that of infertile non-consanguineous patients (group 2) and that of proven fertility
subjects (group 1). Sperm analysis was performed by light and transmission electron microscopy (TEM). TEM data
was mathematically elaborated. Fluorescence in situ hybridization (FISH) analysis for chromosome 18, X and Y was performed
in sperm nuclei for aneuploidy evaluation. The progressive motility was reduced in groups 2 (p < 0.05) and 3
(p < 0.01), compared to group 1, and in group 3 versus group 2 (p < 0.01). Regarding TEM scores, fertility index was reduced
in group 3 (p < 0.01); the percentages of sperm apoptosis, necrosis and immaturity were significantly higher in
groups 2 and 3 versus group 1 and in group 3 vs. group 2 (except for necrosis). FISH analysis showed increased frequency
of diploidy (p < 0.01) in groups 2 and 3 vs. group 1.
The consanguinity seems to influence the spermatogenetic process from a morphological point of view, by reducing the
motility and fertility index and increasing sperm apoptosis and immaturity; chromosome meiotic segregation was not affected
by the condition of consanguinity
Generazione «Controspazio». Il ruolo di un progetto culturale nel dibattito architettonico italiano (1969-1981)
No full textLe tematiche affrontate nella tesi si sviluppano intorno alle vicende editoriali proprie alla rivista di Architettura e Urbanistica «Controspazio», fondata nel 1969 da Paolo Portoghesi a Milano e da lui diretta sino al 1981. Attraverso la ricerca bibliografica, l’indagine dei periodici coevi, il sondaggio degli archivi dei protagonisti e soprattutto il confronto con la rivista stessa, vale a dire la fonte primaria su cui basare le indagini, il lavoro di ricerca prova a chiarire l’implicazione e soprattutto il ruolo di «Controspazio» nel dibattito architettonico italiano tra la fine degli anni Sessanta e per tutto il decennio successivo. La rivista, infatti, è stata la lente attraverso la quale guardare un intero periodo dell’architettura italiana, con i suoi temi e i problemi che i progettisti hanno affrontato. A partire dal suo indirizzo di fondo, ossia la rifondazione disciplinare, la tesi indaga una serie di questioni che si attestano intorno a questo orizzonte di interesse. Il tema teorico dell’autonomia dell’architettura, il problema del rinnovamento della didattica, le questioni urbane e morfologiche che maturano soprattutto intorno alla scuola milanese e veneziana, il confronto con la matrice storica che caratterizza in modo particolare i suoi ultimi anni di pubblicazione (1976-1981) sono individuati come alcuni tra i principali argomenti di discussione.The topics addressed in the thesis revolve around the editorial events related to the Architecture and Urbanism magazine "Controspazio," founded in 1969 by Paolo Portoghesi in Milan and directed by him until 1981. Through bibliographic research, analysis of contemporaneous periodicals, surveys of key figures' archives, and primarily engaging with the magazine itself as the primary source for the investigation, the research work attempts to clarify the implication and, especially, the role of "Controspazio" in the Italian architectural debate from the late 1960s throughout the subsequent decade. Indeed, the magazine served as a lens through which to view an entire period of Italian architecture, with its themes and the problems that designers faced. Starting from its fundamental direction, namely disciplinary redefinition, the thesis explores a series of issues that revolve around this sphere of interest. The theoretical theme of architectural autonomy, the issue of educational renewal, urban and morphological questions that primarily evolved around the Milanese and Venetian schools, and the comparison with the historical framework that particularly characterized its last years of publication (1976-1981) are identified as some of the main topics of discussion
The role of transmission electron microscopy analysis in different cases of reduced motility in human spermatozoa
No full textThe aim of this review is to highlight the pivotal role of transmission electron microscopy (TEM) analysis in the diagnosis of human sperm pathologies related to flagellum and affecting motility.
The analysis of sperm motility plays a central role in the evaluation of male fertility, as it is known that a high percentage of poorly motile or immotile sperm will not be able to fertilize. The study of sperm flagellum and its abnormal forms is generally carried out by light microscope with obvious technical limitations. Only the use of TEM allows for the performance of an ultrastructural evaluation of sperm flagellar assembly with a precise characterization of anomalies, also extrapolating the functional aspect. Severely reduced or completely absent sperm motility in subfertile or infertile men is associated with submicroscopic alterations in the cytoskeletal structure of sperm flagellum, in the mitochondria structure and assembly, in the axonemal pattern and periaxonemal accessory structures, such as the outer dense fibres and fibrous sheath. Sperm anomalies are classified as non-specific, or non-systematic sperm defects, or as systematic sperm defects. The first and most frequent type is related to a heterogeneous combination of randomly distributed alterations affecting the head and the tail organelles in a varied percentage in sperm ejaculate. These alterations can be related to andrological pathologies or to other endogenous or exogenous factors. Necrozoospermia, an extreme manifestation of asthenozoospermia, is, a rather rare phenomenon characterized by an increase in non-viable sperm up to the persistent presence of 100% dead spermatozoa in different ejaculates from the same patient. TEM has proved to be the only tool able to specifically characterize the morphological features of the systematic sperm defects in which an identical and specific alteration affects the vast majority of the sperm population in sterile patients. These defects tend to show family clustering and are significantly more frequent in individuals with a history of consanguinity. The most documented sperm defects of supposed genetic origin affecting the tail structures include: "Dysplasia of Fibrous Sheath", "Primary Ciliary Dyskinesia ", "Detached tail", "Absence of fibrous sheath ", "Absent axoneme"
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