Total Assimilation in Persian Phonology: A Modified Contrastive Specification Account

Nowadays the main stream in the most fields of linguistics including phonology is minimalism and redundancy removing, which derives from the principle of the economy of language. The advent of under specification theory in the late 19th century can be considered as the beginning of redundancy removing in the domain of phonology. During recent decades different versions of under specification such as Radical Under specification, Contrastive Specification and Modified Contrastive Specification (MCS) have been presented. Modified Contrastive Specification (MCS), which is the finding of Toronto Phonology School is based on Contrastive Hypothesis in which a contrastive hierarchy is applied to specify the contrastive features. It is believed that only contrastive features are specified in phonological representations and redundant values never exist in underlying representations. This paper aims to present a novel analysis of total assimilation process in terms of the manner of articulation in consonant clusters having the structures of –st and –zd in Persian which is an active process in phonology of Persian. Working within the framework of the MCS, through drawing a contrastive hierarchy for phonological features, this paper leads to this conclusion that the feature [continuant] in Persian consonants is a contrastive feature so by spreading this feature, the coronal stops /t/, /d/ assimilate to fricatives /s/ and /z/ respectively. To represent contrast and markedness in this system, we have proposed a contrastive hierarchy of [son] > [lab] > [cont]> [voiced] for consonants involved in the process of total assimilation in Persian

DNA fragmentation of spermatozoa and assisted reproduction technology

Despite the ever-increasing knowledge of the fertilization process, there is still a need for better understanding of the causes of sperm DNA fragmentation and its impact on fertilization and pregnancy. For this reason, human sperm DNA fragmentation was investigated by means of the terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) assay and the production of reactive oxygen species (ROS) in the ejaculate and in the spermatozoa themselves. These data were correlated with fertilization and pregnancy data from IVF and intracytoplasmic sperm injection (ICSI) patients. Sperm DNA fragmentation did not correlate with fertilization rate, but there was a significantly reduced pregnancy rate in IVF patients inseminated with TUNEL-positive spermatozoa. ICSI patients exhibited the same tendency. This implies that spermatozoa with damaged DNA are able to fertilize an oocyte, but at the time the paternal genome is switched on, further development stops. The determination of ROS in the ejaculate and the percentage of ROS-producing spermatozoa revealed markedly stronger correlations between sperm functions (i.e. motility) and the percentage of ROS-producing spermatozoa. The influence of seminal leukocytes, known to produce large amounts of oxidants, on sperm DNA fragmentation should not be neglected.Articl

Influence of deoxyribonucleic acid damage on fertilization and pregnancy

Objective To investigate sperm DNA damage in relation to fertilization and pregnancy. Design Prospective study. Setting The Institute of Reproductive Medicine, Giessen, Germany. Patient(s) Semen collected from 249 patients attending the IVF program. Main outcome measure(s) The percentage of terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling- (TUNEL-), Fas-, and annexin-V-positive sperm and the proportion of green-fluorescing sperm in the acridine orange stain was determined and correlated with sperm concentration, motility, fertilization, and pregnancy. Result(s) Significant correlations with the concentration of motile sperm were only found for the acridine orange stain (before and after sperm separation) and for the TUNEL assay (after sperm separation). Moreover, patients whose sperm had a high percentage of DNA fragmentations showed significantly lower pregnancy rates (TUNEL assay: 19.05% vs. 34.65%; acridine orange stain: 24.58% vs. 37.93%). The apoptosis parameters (annexin V binding and Fas expression) showed no statistically significant differences. Conclusions Our data clearly demonstrate that DNA fragmentation, as determined by the TUNEL assay, is predictive for pregnancy in IVF. This implies that spermatozoa with DNA fragmentation can still fertilize an oocyte but that when paternal genes are "switched on," further embryonic development stops, resulting in failed pregnancy. It seems that, at least in the patients we analyzed, apoptosis in the sperm does not play a role for fertilization. This would imply that DNA fragmentation in human spermatozoa is caused by external factors, such as reactive oxygen species, rather than by apoptosis. © 2004 by American Society for Reproductive Medicine.Articl

Urogenital inflammation: Changes of leucocytes and ROS

The presence of excess leucocytes in the semen has been associated with male infertility. According to the WHO, concentrations of more than 10 leucocytes ml-1 are considered as leucocytospermia, indicating genital tract infections. Up to now, no consensus has been achieved on how leucocytes should be quantified in semen. Using the peroxidase staining and monoclonal antibodies to CD15, CD45 and CD68, we found significant differences between the detection methods. Only 47.4% of the semen samples that were assessed as leucocytospermic by CD45 were identified as such by peroxidase staining. The concentration of peroxidase-positive cells was significantly correlated with polymorphonuclear granulocyte (PMN) elastase (P < 0.0001). However, a negative correlation of peroxidase-positive cells with the sperm concentration was only found in oligozoospermic patients (P < 0.0001). Moreover, the slightly positive correlation with normal sperm morphology seems to be applicable only in cases of oligozoospermia. Significant negative correlation of the number of peroxidase-positive cells were found for both maximal inducible acrosome reaction (P = 0.0219) and the inducibility of acrosome reaction (P = 0.0370), indicating a rather deleterious effect of leucocytes on this important sperm function. Concerning the result in the in vitro fertilization programme, none of the examined parameters (PMN elastase, concentration of round cells and peroxidase-positive cells) showed a correlation with either fertilization or pregnancy. This result seems to be reasonable as severely damaged spermatozoa and leucocytes are eliminated from the ejaculate by different sperm separation methods. Interestingly, a significant negative correlation of the TUNEL assay as a measure of sperm DNA fragmentation was found only with pregnancy (P = 0.006) but not with fertilization. As DNA fragmentation can also be caused by ROS that are generated by leucocytes, this causality should not be neglected.Conference Pape