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The study demonstrated Bifidobacterium infantis to ferment purified human milk oligosaccharides (HMO) as a sole carbon source, while another gut commensal, Lactobacillus gasseri, did not ferment HMO. The results support the hypothesis that HMO selectively amplify bacterial populations in the infant intestine.

There are over 200 identified recessive diseases linked to the X-chromosome, which affect males only. Many of these diseases can be diagnosed prenatally by the examination of fetal cells obtained by chorion villus sampling or by amniocentesis. Other diseases may not be able to be diagnosed specifically, but the sex of the fetus can be determined. If the fetus is a male, then he has a chance of having the disease, in which case abortion can be offered. With in vitro fertilization techniques, the embryos can be diagnosed for the genetic defect before implantation in the mother's uterus, and only those embryos without defects would be implanted. The first established pregnancies from embryos that were biopsied and analyzed before implantation are reported in two couples that were at risk of transmitting adrenoleukodystrophy and X-linked mental retardation. Adrenoleukodystrophy is a rare disease that is characterized by degeneration of the adrenal gland and degeneration of myelin which surrounds the cerebrum, resulting in mental deterioration and blindness. A biopsy of a single cell was taken at the stage where the embryo contained six to eight cells. Besides a reduction in cell mass, the embryos are unaffected by removal of one or two cells at the eight-cell stage. Using a technique where small amounts of DNA are amplified to levels which can be analyzed, the sexes of the embryos were determined. Only female embryos were implanted. The rates of pregnancy after transfer of biopsied embryos appears to be the same as the transfer of intact embryos. Both women were confirmed as having normal female twins as determined by chorion villus sampling and ultrasonography. The analysis of preimplantation embryos for genetic defects can diagnose other X-linked diseases such as Lesch-Nyhan and Duchenne muscular dystrophy. This technique is being developed for cystic fibrosis and for other inherited diseases where the nature of the genetic defect is known. (Consumer Summary produced by Reliance Medical Information, Inc.)

The UK House of Commons voted on 3 February to legalize a gene-therapy technique that could help women to avoid passing genetic defects on to their children through mutations in [...]

For a man battling cancer, preserving the option to have children later in life is simple: store samples of semen. Even a single ejaculate contains millions of sperm that can [...]

A method for artificial fertilization of lancelet eggs is described, and the egg coats are studied for the first time by transmission electron microscopy. Large, ovarian oocytes and spawned, unfertilized eggs (which are about 140 [micrometer] in diameter) are surrounded by a coarsely granular vitelline layer about 1 [micrometer] thick and a jelly layer a few micrometers thick. The egg cortex is crowded with a monolayer of cortical granules, each with an average diameter of approximately 3.5 [micrometer]. About 20 to 30 s after insemination, a cortical reaction occurs almost simultaneously over the entire egg surface. The cortical granules undergo exocytosis, and part of their content evidently forms a dense layer 30 nm thick against the inside of the vitelline layer: both layers together constitute the fertilization envelope, which begins elevating from the egg surface. By 80 s after insemination, the jelly layer has disappeared, and beneath the fertilization envelope the bulk of the ejected cortical granule material has become organized into a hyaline layer with a finely fibrogranular consistency. By 20 min after insemination, the perivitelline space between the fertilization envelope and the egg surface has attained its maximum width of roughly 150 [micrometer], and both the hyaline layer and the vitelline layer component of the fertilization envelope are much attenuated and remain so until hatching about 9 h after insemination. Egg coats are compared among major deuterostome groups, and the results imply that the ancestral chordate may have been an unspecialized appendicularian.

Researchers in Japan have turned mouse stem cells into egg cells that, in turn, gave rise to healthy offspring. Katsuhiko Hayashi, Mitinori Saitou and their colleagues at Kyoto University added [...]

Making a healthy baby through in vitro fertilization (IVF) requires choosing the best sperm, the best egg and, of course, the best embryo. For the past 25-30 years, fertility experts [...]