- 'Lab-made sperm' fertility hope Scientists have proved for the first time that sperm grown from embryonic stem cells can be used to produce offspring.
- And Then There was YHow the afterthought to the Human Genome Project broke the chromosomal mold The Y chromosome gets no respect. Regarded as a genetic junkyard with little to offer but sex, genomes have commonly rolled off the presses without a nod to Y. Then there's the matter of decay. Without a recombination partner, genetic insults whittle away the already diminutive Y, suggesting the chromosome's, and by extension man's, eventual extinction.
damage can be passed down the generations There
is now evidence that radiation damage can be passed down
the generations DURING the 1950s, one of the least inviting
holiday destinations on the planet would have been Semipalatinsk,
in Kazakhstan. It is a mere 150km (about 100 miles) from
the Soviet Union's main atomic-bomb testing site and it
was subjected to the fallout from 118 tests over 13 years.
From this and other grim and inadvertent experiments, it
is clear that nuclear radiation is a powerful cause of mutations
in human DNA in the ordinary cells (those that are not concerned
with reproduction) of the body. Such mutations can, in turn,
cause cancers. But evidence supporting another oft-voiced
fear—that radiation-induced mutations might affect human
reproductive (or “germ-line”) cells—is weak and surprisingly
ωαρίων και ιστού ωοθηκών για την επαναφορά της γονιμότητας
μετά από χημειοθεραπεία (Έγγραφο Word,
transplant pregnancy first
A woman has become pregnant after having an ovary tissue
transplant for the first time, it has emerged.
The breakthrough gives hope to thousands of cancer patients
whose treatment can make them infertile.
σπερματοζωάρια παρέχουν και mRNA
Λονδίνο: Τα σπερματοζωάρια δεν παρέχουν μόνο χρωμοσώματα
στο ωάριο κατά τη γονιμοποίηση αλλά και mRNA, όπως αποδεικνύουν
για πρώτη φορά Αμερικανοί και Βρετανοί επιστήμονες σε μελέτη
τους που δημοσιεύεται στο έγκυρο επιστημονικό περιοδικό
Οι επιστήμονες του Wayne State University στο Ντιτρόιτ κατέληξαν
στο συμπέρασμα αυτό αφού προσδιόρισαν έξι διαφορετικά μόρια
mRNA τα οποία περιέχονταν στα σπερματοζωάρια και το γονιμοποιημένο
ωάριο, αλλά όχι και στο μη γονιμοποιημένο.
Πιστεύεται ότι το συγκεκριμένο αγγελιοφόρο RNA δρα στο γονιμοποιημένο
ωάριο κατά τέτοιο τρόπο, ώστε να συμβάλλει σημαντικά στην
αρχική ανάπτυξη του εμβρύου.
Όπως αναφέρει χαρακτηριστικά ο Δρ Στέφεν Κράβετς που ηγήθηκε
της έρευνας, η ανακάλυψή τους ενδεχομένως εξηγεί γιατί η
κλονοποίηση συνοδεύεται από τόσο χαμηλά ποσοστά επιτυχίας,
αφού δεν απαιτεί σπέρμα και κατά συνέπεια δεν μεταφέρεται
το αγγελιοφόρο RNA από τα σπερματοζωάρια.
mothers, older fathers
Women aged 35 or more have long been known to have an increased
risk of infertility. But does advancing age in the male
partner have similar effects? The results of previous studies
in this area have been conflicting.
To investigate the risk of infertility associated with paternal
age, researchers from the Human Fertility Research Group
at Paule de Viguier Hospital in Toulouse, France, interviewed
3,287 couples in which both partners were within the range
Does paternal age contribute to infertility?
Investigating the impact of the age of the male on fertility
in a large European database.
Once men reach the age of 40 years they become a risk factor
for infertility, say researchers.
Whereas a maternal age of 35 years of age and above is a
well-known risk factor for infertility, the impact of the
age of the male has been rarely investigated, note Patrick
Thonneau (Paule de Viguier Hospital, Toulouse, France) and
Primates successfully give birth following ovarian cryopreservation
The first successful birth following ovarian cryopreservation
in a primate model was reported at the XVII FIGO World Congress
in Santiago, Chile (2-7 November 2003).
Researchers have reported the first successful birth following
ovarian tissue cryopreservation in a monkey. But they stress
the research remains technically challenging at the current
PGD reduces recurrent miscarriage abortion rate
A study presented at the XVII FIGO World Congress that was
held in Santiago, Chile (2-7 November 2003) shows that less
than one-third of embryos generated from recurrent miscarriage
couples are normal. Preimplantation genetic diagnosis (PGD)
may have a role to play in the diagnosis and management
of patients with recurrent miscarriage, according to Spanish
First human ovarian transplant reported
Indian gynecologists reported the first successful ovarian
transplant in humans at the XVII FIGO World Congress held
in Santiago, Chile (2-7 November 2003).
A patient with Turner’s syndrome has been successfully transplanted
with an ovary from her living sister, said Dr. Parvin Mhatre
(Kothari Hospital, Mumbai, India).
The transplant was carried out from a live donor, who was
26 years old and had two children herself, to her younger
sister, aged 17 years, in March 2002. The recipient had
bilateral streak ovaries and chromosomal configuration of
XO—Turner’s syndrome. The donor and recipient were immunologically
matched by blood group, HLA matching, and lymphocytic cross
Sex ratio at conception shows seasonal variation
Seasonal patterns of conception may help preserve the male
to female sex ratio.
Couples who want to have a boy should try to conceive in
autumn, while the chances of having a girl are increased
by conceiving in spring, study findings indicate.
Given that male fetuses and neonates are more fragile than
females, the study authors believe that the seasonal variation
helps to preserve the sex ratio, by allowing more boys to
be conceived during optimal conditions for pregnancy and
Egg-sharing does not damage a donor's own chance of a baby
say UK researchers
Women who take part in egg sharing programmes run by fertility
clinics are not compromising their chance of having a baby
by donating some of their eggs, according to UK research
published today (Thursday 30 October) in Europe's leading
reproductive medicine journal Human Reproduction.
Danish study finds that taking a long time to conceive is
linked to problems at birth
Women who take more than a year to conceive have a higher
than normal risk of having a premature birth, a full-term
baby with low birthweight, or a Caesarean section, according
to a large Danish study reported (Thursday 30 October) in
Europe's leading reproductive medicine journal Human Reproduction.
Fever impact on semen quality confirmed
Testing the validity of claims that semen quality is affected
by febrile illness.
Semen quality may be impaired by the development of a fever
up to 2 months before ejaculation, study findings suggest.
Although previous publications have stated that "it
is a well-known phenomenon that semen quality can be affected
by febrile illness," the data supporting this claim
are of low quality, note Elisabeth Carlsen (Rigshospitalet,
Blegdamsvej, Denmark) and colleagues.
To address this issue, the researchers examined the influence
of febrile episodes on monthly sperm samples of 27 healthy
men, over a 16-month period.
and p53 inversely correlated in genital tract tumors
Correlating human papillomavirus positivity with p53 over
expression in cervical, vaginal, and vulvar squamous cell
carcinomas. The overexpression of p53 and human papillomavirus
(HPV) infection may reflect independent carcinogenic processes,
While "one well characterized pathway for the induction
of growth arrest and apoptosis is through the activation
of the p53 tumor suppressor protein," human papillomavirus
appears to abrogate this response by targeting the tumor
suppressor for ubiquitin-dependent degradation. Consequently,
it has been suggested that p53 mutations play a role in
HPV negative carcinomas, although evidence of an inverse
relationship between the presence of HPV DNA and mutant
p53 expression is conflicting, explain Yasuko Koyamatsu
(Saga Medical School, Japan) and co-workers.
Fertility first with tissue transplant **
US scientists use ovarian tissue to produce a live monkey
birth, a move which could benefit women made infertile by
cancer treatment. The procedure carried out in a rhesus
monkey could, researchers say, be used for humans.
The development gives new hope to women who have become
infertile following cancer treatment.
New technique allows real-time placenta imaging
Researchers recommend a new imaging technique for staging
human placental development.
Using a new imaging technique, it is now possible to monitor
placental development during pregnancy, reveal researchers
in a finding that holds promise for the real-time diagnosis
of placental pathologies.
"Maldevelopment of placental villous trees and their
blood vessels results in impaired fetal growth, which can
greatly compromise fetal, neonatal, childhood, and adulthood
health," write Justin Konje (University of Leicester,
UK) and colleagues. However, "there are no means of
directly assessing such maldevelopment."
First trimester trisomy screening supported
Researchers test the sensitivity of a combined approach
to first trimester screening for the detection of trisomies
18 and 21. First trimester screening combining biochemical
markers and fetal nuchal translucency for the detection
of trisomies 21 and 18 is an accurate and efficient alternative
to second trimester screening, say researchers.
Perimenopausal depression linked to ovarian function
Examining the relationship between changes in mood and pituitary-ovarian
axis function in perimenopausal women. A normal dietary
intake of isoflavones is linked to lower levels of total
body fat in postmenopausal women, and may prove useful for
the prevention of chronic disease.
"Previous studies suggest an association between isoflavone
supplementation and improved body composition," write
Deborah Goodman-Gruen and Donna Kritz-Silverstein from the
University of California in San Diego, USA. However, "the
effect of usual dietary isoflavone consumption on obesity
among postmenopausal women consuming a typical Western diet,"
has not been reported.
Oxidative stress linked to infertility apoptosis
Investigating whether semen quality is associated with apoptosis
in the presence of oxidative stress.
High levels of reactive oxygen species (ROS) in the semen
of patients with male factor infertility are associated
with increased levels of caspase-mediated apoptosis, a study
While both oxidative stress and high rates of apoptosis
have been independently associated with testicular insufficiency
in male infertility, "it is unclear whether the caspase-mediated
pathway is involved in inducing apoptosis in ejaculated
spermatozoa, and, if so, how it is influenced by oxidative
stress," write researchers, led by Xia Wang from the
Cleveland Clinic Foundation in Ohio, USA.
Iron supplementation improves birth weight
Scientists hypothesize that prophylactic iron supplementation
in early pregnancy reduces anemia and increases birth weight.
Results from a randomized controlled trial suggest that
prenatal prophylactic iron supplementation in iron-replete,
nonanemic women improves birth weight, and may have beneficial
effects on related health care costs.
IVF and ICSI synergy in unexplained infertility
Researchers further examine the value of splitting sibling
oocytes from patients with unexplained infertility between
IVF and ICSI.
The International Federation of Gynecology and Obstetrics
(FIGO) has published its World Report on Women's Health
2003, in a special issue of its journal.
The report consists of a series of articles providing commentary
on a wide range of issues that impact on women's health,
highlighting new developments and initiatives that are leading
to real improvements in care.
Sex selection for social reasons: religious and moral perspectives
Two reports in the 25 September 2003 issue of Human Reproduction
suggest that the coming availability of sex selection technology
is not likely to skew the balance between the sexes. Two
experts in religion and reproductive technology respond
to this report and to the way it might be used in the ethics
and public policy debate over the availability of sex selection
Fetal exposure to two chemicals cause of male reproductive
disorders later in life
Primary author of several recent studies involving di-n-butyl
phthalate (DBP) and linuron (L) discusses his findings and
what they mean for understanding human development.
(Philadelphia, PA) – Over the last ten years, US researchers
have observed a marked increase in some male reproductive
disorders, including undescended testicles, increased instances
of testicular cancer, and decreased sperm count. In the
last 20 years the rates for testicular cancer have grown
almost five-fold in Denmark, yet neighboring Finland has
not experienced such a dramatic increase. In an effort to
explain this phenomenon, scientists have hypothesized that
these human male reproductive deficits may have a common
origin: a disturbance in the level of androgen and other
critical hormones during fetal development. The results
from tests with laboratory animals may help scientists better
understand the effect of fetal exposure to certain chemicals
has on male reproduction abilities later in life.
ART pregnancy indicators defined
Examining the implantation potential of embryos from assisted
reproductive technology cycles with low embryo production.
Researchers claim that cumulative embryo score (ES) can
serve as a predictor of pregnancy in assisted reproductive
technology (ART) cycles, and recommend that the emphasis,
in terms of achieving pregnancy, should be shifted from
ovarian response to the production of viable embryos.
trait boosts IVF success
Can examination of the blastomere nucleus improve implantation
rates in IVF? Japanese researchers have discovered that
blastomere nuclei status may be more important than conventional
features such as fragmentation and uniformity in predicting
embryo implantation rates.
"In this analysis, the venerable tradition of gathering
information on past infections and symptoms of past infection
did not help predict tubal disease among infertile nulligravid
women." This conclusion from an evaluation of history-taking
in 321 women is the source of much debate among specialists
in the latest issue of the journal Fertility and Sterility.
variability reveals menopause timing
Determining how accurately menstrual characteristics can
predict time to menopause. Simple questions about menstrual
variability can help identify how soon a woman is likely
to go through the menopause, US researchers have found.
Sylvia Taylor (Columbia University, New York) and colleagues
interviewed 326 women, aged 44 to 56 years, on six definitions
of menstrual variability. Participants had all menstruated
in the past year, and were followed-up for around 4.8 years-until
they reached menopause (12 months without menstruation)
or the study ended.
Embryoid bodies contain primordial germ cells that can mature
into male gametes By David Secko.
Mouse germ cell development requires primordial germ cells
(PGCs) in order to develop the egg and sperm cells (gametes).
These PGCs are generated in a region in the embryo that
also gives rise to the first blood lineages. Embryonic stem
(ES) cells, when differentiated into embryoid bodies (EBs),
also maintain blood development. In addition, the surface
antigen SSEA1-a marker of undifferentiated ES cells and
PGCs-persists at low levels in different Ebs, suggesting
that ES-derived embryoid bodies could also support PGC formation.
In the December 11 Nature, Niels Geijsen and colleagues
at the Whitehead Institute for Biomedical Science have isolated
PGCs from embryoid bodies and observed that they can form
male gametes (Nature, DOI:10.1038/nature02247, December
levels of PCBs found to influence sex ratio
Women with high blood levels of polychlorinated biphenyls
are more likely to give birth to a girl than a boy. Maternal
exposure to polychlorinated biphenyls (PCBs), primarily
through eating contaminated fish, appears to result in an
abnormal sex ratio with a preponderance of female offspring,
ovarian reserve linked to recurrent miscarriage
An association between ovarian reserve and the risk of recurrent
miscarriage is proposed.
Diminished ovarian reserve, as evidenced by elevated serum
FSH and/or estradiol (E2) levels, may be associated with
recurrent pregnancy loss (RPL) in some cases, research indicates.
genetic response in animal species to global warming.
For the first time ever, a University of Alberta researcher
has discovered that an animal species has changed its genetic
make-up to cope with global warming. In the past, organisms
have shown the flexibility--or plasticity--to adapt to their
surroundings, but this is the first time it has been proven
a species has responded genetically to cope with environmental
fate genes. Flk1 and Tal1 control vascular and hematopoietic
development during embryogenesis.
| Tudor P Toma Endothelial precursors and primitive hematopoietic
cells are closely associated during development. They are
thought to originate from a common progenitor, the hemangioblast,
but the molecular mechanisms that control the fate of hemangioblasts
have been unclear.
mutations may be associated
with some hereditary pancreatic cancers
BRCA2 mutations may be associated with some hereditary pancreatic
cancers Mutations in the breast cancer susceptibility gene
BRCA2 may be associated with a predisposition to familial
(hereditary) pancreatic cancer, a new study suggests. The
findings appear in the February 5 issue of the Journal of
the National Cancer Institute.
heterogeneity of Icelanders
Research undertaken by Professor Einar Αrnason at the University
of Iceland, Reykjavik and published in the January 2003
issue of Annals of Human Genetics highlights the inaccuracy
of claims that Icelanders are a 'genetically homogenous'
of Genes on the Drosophila X Chromosome
Showing Male-Biased Expression
Sex chromosomes are primary determinants of sexual dimorphism
in many organisms. These chromosomes are thought to arise
via the divergence of an ancestral autosome pair and are
almost certainly influenced by differing selection in males
and females. Exploring how sex chromosomes differ from autosomes
is highly amenable to genomic analysis. We examined global
gene expression in Drosophila melanogaster and report a
dramatic underrepresentation of X-chromosome genes showing
high relative expression in males. Using comparative genomics,
we find that these same X-chromosome genes are exceptionally
poorly conserved in the mosquito Anopheles gambiae. These
data indicate that the X chromosome is a disfavored location
for genes selectively expressed in males.