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PubMed1976

Identification of gonococcal cultures by means of their cytoplasmic antigens and an anti-cytoplasm antiserum.

Soluble antigens were released by sonication from the cells of 60 primary cultures of Neiserria gonorrhoeae, 7 other species of neisseriae and 26 "mixed" cultures containing colonies of N. gonorrhoeae and other bacteria. Rabbits were injected with the soluble antigens of four strains of gonococci (clonal types 1 and 2), four other species of neisseriae and ten bacterial genera other than Neisseria. The antigens were tested against the non-absorbed antisera by a counter-immunoelectrophoresis method. It was found that the antiserum produced against the antigens of one N. gonorrhoeae strain, the strain GEK, reacted exclusively with the sonicates of all N. gonorrhoea cultures whether pure or mixed with other microorganisms. In contrast, the antisera to the antigens of all other N. gonorrhoeae strains cross-reacted with antigens of N. catarrhalis or N. sicca. Thus, the unique restricted reactivity of the anti-GEK antiserum permits its utilization as an immunological reagent for prompt identification of gonococcal cultures.

Antigens, Bacterial↗
PubMed2000

Intra-cytoplasmic sperm injection versus partial zona dissection, subzonal insemination and conventional techniques for oocyte insemination during in vitro fertilisation.

BACKGROUND: In vitro fertilisation (IVF) and embryo transfer as treatment for male factor infertility is associated with lower fertilisation and pregnancy rates than for other indications. Since the late 1980s several assisted fertilisation techniques have emerged and have been rapidly developed to try to enhance results for couples with male factor infertility, or to help couples with severe male factor for whom conventional IVF was not possible. The technique of partial zona dissection (PZD) was developed to increase the probability that a sperm capable of fertilisation comes in contact with the oocyte. Although this method improved conventional IVF results, the improvement was only marginal and relatively large numbers of sperm are still required. This drawback applied less to the subsequent technique of subzonal microinjection of spermatozoa into the perivitelline space (SUZI). However, for all of these techniques fertilisation rates remained low, rates of polyspermic fertilisation were increased, and cases with a very limited number of spermatozoa in the ejaculate could still not be treated. The advent of intra-cytoplasmatic sperm injection (ICSI) of a single sperm (or sperm head or nucleus) into the oocyte appears to be an important breakthrough. OBJECTIVES: To investigate whether ICSI improves fertilisation and/or pregnancy rates in comparison to other fertilisation techniques. SEARCH STRATEGY: The Menstrual Disorders and Subfertility Group search strategy (see Review Group details) was used to identify trials that had compared ICSI with other infertility techniques, such as PZD, SUZI, conventional IVF and additional IVF. SELECTION CRITERIA: Trials were included if they compared the effects of these techniques on fertilisation and pregnancy outcomes. Only randomised studies were included in this review. DATA COLLECTION AND ANALYSIS: Ten studies met the inclusion criteria for this review. Eight studies compared ICSI with conventional IVF. One study compared ICSI with SUZI and one study compared ICSI with additional IVF. Data was extracted independently by two reviewers. Where relevant data was missing or unclear, the authors had been consulted. Male participants were classified according to their semen parameters, i.e. normal semen (concentration >20 million per ml, motility >50%, morphology >14%), borderline semen (concentration 10-20 million per ml, motility 30-50%, morphology 4-14% normal forms) and very poor semen (concentration <10 million per ml, motility <30%, morphology <4% normal forms). MAIN RESULTS: For couples with normal semen there is no evidence of a difference in fertilisation rates per retrieved oocyte or pregnancy rates between ICSI and conventional IVF. On the other hand, for fertilisation rate per inseminated oocyte, ICSI appears to result in better outcomes than IVF for normal semen. For couples with borderline semen ICSI results in higher fertilisation rates (all) than IVF. Couples with very poor semen will have better fertilisation outcomes with ICSI than with SUZI or additional IVF. REVIEWER'S CONCLUSIONS: There is evidence from this systematic review that fertilisation rates are significantly better with ICSI than IVF in couples with borderline semen. When the semen parameters are normal there is insufficient evidence of a difference in effectiveness between ICSI and IVF when retrieved oocytes were the unit of randomisation. However, there was a small but statistically significant increase in fertilisation rate when inseminated oocytes were the unit of randomisation. Total fertilisation rates were significantly reduced in ICSI cycles than IVF but there were no damaged oocytes in IVF cycles regardless of the semen parameters.

Embryo Implantation↗
PubMed1978

Nuclear suppressors of the [poky] cytoplasmic mutant in Neurospora crassa. III. Effects on other cytoplasmic mutants and on mitochondrial ribosome assembly in [poky].

We have previously isolated six non-allelic, nuclear mutations (sui loci) that partially suppress the growth, respiratory and cytochrome abnormalities of the extranuclear [poky] mutant. A comparison of the mitochondrial ribosome profiles of suppressed and unsuppressed [poky] strains revealed that five of the six suppressors alleviate at least partially the deficiency of mitochondrial small ribosomal subunits that is associated with the [poky] genotype. Six independently isolated Group 1 extranuclear mutants, namely [exn-1], [exn-2], [exn-4-a1, [stp-b1], [SG-1] and [SG-3-A1, which have growth and cytochrome phenotypes similar to [poky] also were found to be deficient in small subunits of mitochondrial ribosomes. Using cytochrome aa3 and b production as a criterion for mitochondrial protein synthesis, it could be shown that the nuclear su I suppressors of [poky] also suppress the other six Group I extranuclear mutants. However, differences in the efficiencies of suppression by suI suppressors suggest that at least some of Group I extrachromosomal mutants are not simply re-isolates of [poky], but represent distinct extranuclear mutations.

DNA, Mitochondrial↗