Hebrew University scientists have reported a “major breakthrough” in understanding the molecular basis for Prader-Willi syndrome (PWS) – perhaps the most studied among the class of diseases that involves defects in parental imprinting.
The work, described in an online edition of the prestigious journal Nature Genetics, was led by cancer researcher Prof. Nissim Benvenisty, who is director of the stem cell unit at HU’s Alexander Silberman Institute of Life Sciences. Also participating were his doctoral student Yonatan Stelzer, graduate student Ido Sagi and Drs. Ofra Yanuka and Rachel Eiges.
Parental imprinting is a mode of inheritance that results in a small subset of genes to be expressed exclusively from either the mother or father. The disease is a multisystem disorder characterized by learning disabilities, a constant feeling of hunger, excessive weight gain and defective sexual development and is known to result from aberrations in paternal genes in what is known as the Prader-Willi genomic region of chromosome 15.
“What characterizes this chromosomal region is that paternal genes are active, while the maternal genes are inactive. And while most people would have one normal working and one silenced set of these genes, people with Prader-Willi syndrome have only a defective set (the paternal one) and a silenced (maternal) set,” explains Stelzer.
To achieve a greater understanding of this process, the researchers created a model for the syndrome by reprogramming skin cells from PWS patients into embryonic-like cells.
Using this system, they showed that the genes expressed from the father are actually affecting and silencing the genes that are expressed from the mother. These findings have significance in the way that we view parental imprinting and in particular the molecular basis of Prader-Willi syndrome, the scientists say.
Future research should allow further characterization of the contribution of this novel genetic region to the origin of this disease, and it may pave the way for identification of possible treatment and characterization of PWS patients. Furthermore, the identification of functional, genomic cross-talk in regions containing parental imprinted genes may significantly change our overall understanding of the evolution of this phenomenon in placental mammals, say the researchers.
SCHNEIDER CHILDREN’S HOSPITAL AGAIN GETS EXCELLENCE AWARD
Clalit Health Services, the largest of the four public health funds, chose Schneider Childen’s Medical Center in Petah Tikva for the second year in a row as its outstanding hospital. The prize ceremony was held earlier in May. Clalit director-general Eli Depes presented the award to Schneider director Prof. Joseph Press.
Ironically, when the late Irving Schneider, the hospital’s benefactor, launched his campaign to establish the country’s first free-standing children’s hospital, he was warned that it would be a “white elephant.”
But since its opening in 1991, it has been a great success in treatment and research and is full to capacity with children who need different treatment that than given to adults.
POLLING THE KIDS ABOUT FOOD
Usually, young children are not asked whether they enjoy the food served them in pre-school frameworks; sometimes, they vote with their forks by not eating it. Now the Jerusalem Municipality have actually surveyed kindergarten children who are served more healthful meals in class. The new menu includes whole grains, less salt and sugar, more fruits and vegetables and unprocessed meats.
According to the survey in 15 municipal kindergartens chosen to take part in the pilot program initiated by deputy mayor Rachel Azaria, whole-grain couscous was the most popular, while turkey pieces and zucchini were the least liked.
The municipality said it would make changes in the menus according to the children’s preferences of healthful foods and expand the program to all the city’s kindergartens.
The whole-grain couscous received an 8.4 rating out of 10, followed by a lentil dish (8), cooked vegetables served with couscous (7.9), cooked carrots (7.6). whole-grain pasta (7.6) and chicken thighs. Green beans in sauce received only 6.8, zucchini in sauce 6.6, while most of the children refused to eat the turkey pieces in sauce (a rating of only 5.9). Parents and kindergarten teachers will also provide feedback before decisions are made.
Mayor Nir Barkat commented that “children are our customers, and since it’s important to us that they get healthful and tasty food, we will continue to ask them what they think.
Azaria added that “unlike in our day, young children today eat their main meal in the afternoon in their afternoon framework and not at home. What they eat will determine their eating habits for their whole lives.”
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