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  • 1
    ISSN: 1573-7330
    Keywords: subzonal sperm insertion ; partial zona dissection ; sperm factors ; oligoasthenoteratozoospermia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Subzonal sperm insertion and partial zona dissection were applied in 250 in vitro fertilization cycles in couples (n =200) with abnormal semen analyses; 61 clinical pregnancies were established (24% per egg retrieval). Patients were selected without using minimal cutoff criteria. The study included patients with 0% normal sperm forms (strict criteria), no motile sperm (but some live cells), and sperm counts which could be assessed only after centrifugation. Patients were categorized into three subsets. Group A (n =116 cycles) failed to fertilize in a previous cycle. Group B (n =40) was excluded from IVF due to the severity of sperm profiles, such as a maximum of 2% normal forms. Group C (n =94) constitutes those patients for whom a standard cycle could possibly result in failure. Monospermic fertilization rates were 18% (A), 19% (B), and 24% (C). The incidences of embryo replacement were 63% (A), 53% (B), and 69% (C). Rates of clinical pregnancy were 22% (A), 23% (B), and 28% (C). The presence of one, two, or three semen abnormalities did not correlate with the outcome of microsurgical fertilization. Twenty-two percent of patients with combined oligoasthenoteratozoospermia became pregnant. Moreover, ongoing pregnancies were established in instances with 0% normal sperm forms and no progressively motile spermatozoa. It is concluded that stringent cutoff criteria may not be necessary when both partial zona dissection and subzonal sperm insertion are performed efficiently.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of assisted reproduction and genetics 9 (1992), S. 97-101 
    ISSN: 1573-7330
    Keywords: subzonal sperm insertion ; number of male pronuclei ; polyspermy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The subzonal sperm insertion technique was applied to assess the potential of motile human spermatozoa to form pronuclei. In 184 mature human oocytes, subzonal sperm insertion was used as the primary mode of insemination in cases with abnormal semen analyses. Oocytes (n =131) that failed to fertilize in vitro in cases with normal semen profiles were also micromanipulated for secondary insemination. The frequency of sperm fusion, expressed as a percentage, was defined as the total number of male pronuclei formed divided by the total number of spermatozoa inserted subzonally. Our results indicate that 37% of spermatozoa from men with normal semen are able to fuse with the oolemma and decondense within the ooplasm, when placed in the perivitelline space of the oocyte. Excluding the oocytes that appeared morphologically abnormal (presence of cytoplasmic inclusions such as refractile bodies within the ooplasm), the frequency of sperm fusion increased to nearly 60%. Moreover, 14% of subzonally inserted spermatozoa from men with abnormal semen analyses demonstrated an ability to form a pronucleus. The incidence of polyspermy was high, ranging from 30 to 80% in the different groups studied. It is therefore concluded that the human oolemma provides little protection against multiple sperm fusion and that the frequency of gamete fusion is unexpectedly high, even when the spermatozoa are derived from infertile men.
    Type of Medium: Electronic Resource
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