Household insecticides associated with increased risk of childhood leukaemia
Household exposure to pesticides and risk of childhood acute leukaemia; Occupational and Environmental Medicine 2006, 63: 131-4
Household insecticides may increase the risk of childhood leukaemia, suggests French research in Occupational and Environmental Medicine .
Leukaemia is the most common childhood cancer in France, affecting 43 in every million children every year.
The findings are based on 280 children newly diagnosed with acute leukaemia and a further 288 children matched for sex and age, but free of the disease.
Detailed face to face interviews were carried out with each of their mothers. These included questions about the employment history of both parents, the use of insecticides in the home and garden, and the use of insecticidal shampoos to eradicate head lice.
The risk of developing acute leukaemia was almost twice as likely in children whose mothers said that they had used insecticides in the home while pregnant and long after the birth.
Exposure to garden insecticides and fungicides as a child was associated with a more than doubling of the risk of acute childhood leukaemia. And the use of insecticidal shampoos to eradicate head lice, based on what the mothers had said, was associated with almost double the risk.
The authors say that no one agent can be singled out and a causal relation between insecticides and the development of acute childhood leukaemia "remains questionable,"
They add: "However, the consistency of our results and the results from previous studies suggests that it may be opportune to consider preventive action."
Comedy films boost blood flow to the heart
Impact of cinematic viewing on endothelial function; Heart 2006, 92: 261-2
Watching comedy films boosts blood flow to the heart, finds a small study in the journal Heart.
Researchers asked 20 healthy young adults to watch 15 to 30 minute segments of sad and humorous films, a minimum of 48 hours apart.
Examples of sad films included the opening scene of Saving Private Ryan and examples of comedy films included There's Something About Mary.
Participants were asked to abstain from drinking alcohol, using vitamins or herbs, or taking aerobic exercise the evening before the experiment, as all these can affect blood flow.
In all, 160 measurements of brachial artery blood flow were taken before and one minute after phases of laughter or sadness. The brachial artery runs from the shoulder to the elbow, and is a good indicator of blood flow around the body.
Brachial artery blood flow was reduced in 14 of the 20 participants after watching movie clips that caused distress. But it was increased in 19 of the 20 participants after watching movie clips that elicited laughter. The difference in flow between sad and happy responses exceeded 50 per cent.
The extent of the impact of watching a sad film was of the same magnitude as remembering episodes of anger and doing mental arithmetic, say the authors, while the impact of watching a funny film was equivalent to a bout of aerobic exercise or starting on statin treatment.
Mayo collaboration identifies gene in childhood kidney disease
New insight into related disorders
An international research collaboration led by Mayo Clinic has identified a new gene involved in causing the inherited kidney disorder, Meckel-Gruber syndrome (MKS). Children with MKS have central nervous system deformities as well as abnormal cysts in their kidneys, and usually die shortly after birth. The findings appear in the current edition of Nature Genetics (http://www.nature.com/ng/index.html). In addition to Mayo Clinic, the collaboration involved researchers from the Indiana University School of Medicine in Indianapolis, and the University of Birmingham, England. Significance of the Finding
This news is of immediate importance to MKS families who may now have their blood screened for the defect and seek genetic counseling. The finding also is important for advancing understanding of what goes wrong in common birth defects, such as neural tube defects, as well as for related disorders such as more common forms of polycystic kidney disease (PKD). PKD accounts for more than 5 percent of end-stage kidney disease in the United States and Europe.
"This gene has immediate relevance for a small number of families, but the broader implications are important for the understanding they bring of how cysts develop in the kidney," explains Peter Harris, Ph.D., the Mayo Clinic nephrology researcher who led the research team. "There is a kind of common linkage among these diseases. Our hope is that this new finding will aid us to devise new treatments for a broad category of disabling disease."
Meckel-Gruber kidney disease is separate from, though related to, PKD in that some of the same things go wrong to cause the abnormal formation of cysts that disrupt kidney function. Knowing the identity of one key gene involved in MKS is a first step to understanding the disorder and eventually devising therapies to blunt its effects. Treatments are being developed for the more common forms of polycystic kidney disease.
The current work is an extension of Mayo researchers' groundbreaking work for more than a decade that has helped to reveal the genetic basis of PKD and to develop therapies. In that time, Mayo researchers have identified key genes driving the most common form of the disease in adults and in infants.
Method: From Rat to Humans
The research collaboration brought together Mayo's expertise in polycystic disease genetics with an animal model characterized in Indiana: a rat that mimicked PKD but that also showed symptoms of abnormal brain development. These clinical characteristics linked to a gene made this a useful model for an atypical form of PKD. The researchers identified the neighborhood in the model's genome where the error likely occurred, ultimately finding one gene that was defective. They then looked at the same neighborhood in the human genome for evidence of a disease with symptoms similar to the model (the bottom of chromosome 8) and found Meckel-Gruber syndrome type 3 (MKS3). Screening the corresponding gene, they identified similar changes in the MKS3 patients (characterized by the Birmingham group) and identified the disease gene.
http://tinyurl.com/77a4f
Antidepressant therapy for major depression in children and adolescents
Dr. Graham Emslie, a world leader in research into the use of antidepressants in children and adolescents, along with colleagues Amy Cheung and Taryn Mayes review the evidence from published and unpublished randomized controlled trials on the benefits and harms (including suicide and suicide ideation) of antidepressant therapy for major depressive disorder in pediatric patients. They also make clinical recommendations based on their findings.
p. 193 The use of antidepressants to treat depression in children and adolescents -- A.H. Cheung et al
Absence of critical protein linked to infertility
The absence of a key protein may lead to infertility.
Researchers at the University of Illinois at Urbana-Champaign report that experiments involving mice -- to be detailed in the Proceedings of the National Academy of Sciences -- indicate that the transcription factor protein C/EBPb must be present in the uterus for pregnancy to occur. The study appears online this week at the PNAS Web site.
Without it, they say, an embryo cannot survive in uterine tissue or attach to a mother's blood supply. Other genes also play roles, but C/EBPb is critical for implantation of an embryo, said Milan K. Bagchi, a professor of molecular and integrative physiology.
C/EBPb is scientifically known as CCAAT/Enhancer Binding Protein beta. It is regulated by the hormones estrogen and progesterone. In normal conditions, the protein, driven mostly by progesterone, is expressed rapidly and in large quantities during the critical four-day implantation period in mice, Bagchi said.
During this period, an embryo attaches to the wall of the uterus, advances into it and eventually attaches to the blood supply and forms the placenta. For a successful pregnancy to occur, stromal cells of the uterus must be transformed into decidual cells, which secrete nutrients that allow the embryo to survive until it plugs into the blood supply. C/EBPb is necessary for decidualization, the researchers discovered.
"This protein in the mouse is also in humans," Bagchi said. "We believe it plays a critical role in human pregnancy. It is expressed in the human endometrium at a time that coincides with the time of implantation. We have demonstrated very clearly in the mouse that in the absence of C/EBPb there is no decidualization. We transferred viable mouse embryos from healthy mice into mice lacking the gene, and pregnancy failed."
The project began more than four years ago. First, researchers used DNA microarrays to identify gene expression under normal and abnormal conditions during implantation. After messenger RNA profiling zeroed in on C/EBPb's activity, the researchers collaborated with Peter F. Johnson of the National Cancer Institute's Laboratory of Protein Dynamics and Signaling, who created mice that lacked the protein.
The experimental mice were then used to observe the relationships of the hormones and their receptors with the protein under varying conditions during the critical implantation period. In doing so, researchers determined that C/EBPb is a critical mediator of steroid hormone responsiveness in the uterus.
"This gene is expressed when the uterus is ready for embryo attachment," said co-author Indrani C. Bagchi, a professor of veterinary biosciences in the College of Veterinary Medicine at Illinois. "Its presence indicates a window for success."
If the findings are replicated in human tissue, as expected, she said, the protein's presence could become a vital gene marker for predicting uterine readiness for pregnancy.
"The success rate for the practice of in vitro fertilization currently is, on average, about 25 percent," she said. "The major problem is that the conditions occurring when the embryo is transferred often are not the best in the uterus. It's not known if the uterus is ready to accept an embryo, so often multiple embryos are transferred in hopes that one will attach. In future studies, confirmation of C/EBPb as a marker that correctly indicates uterine readiness for implantation in the human is likely to alleviate these shortcomings."
Other co-authors of the paper were doctoral student Srinivasa Raju Mantena, postdoctoral researchers Athilakshmi Kannan and Yong-Pil Cheon, and research scientist Quanxi Li, all in Indrani Bagchi's veterinary biosciences laboratory.
