When starting to crawl, babies’ sleep is irregular

Health Scan: Tennesse researchers explore whether homosexuality is genetic.

By JUDY SIEGEL-ITZKOVICH
Toddler (photo credit: Wikicommons)
Toddler
(photo credit: Wikicommons)
Parents of newborns know that they will not get much sleep, especially during the first three or four months after birth. But now, University of Haifa researchers claim that there is another period of sleeplessness – when the baby starts to crawl – that lasts for about another three months.
Dr. Dina Cohen of the university’s human development department, supervised by Prof. Anat Sher, studied the sleeping habits of 28 healthy babies with normal development, aged from four to 11 months. They were monitored by a device called Actigraph that is able to give objective data on sleep habits. The parents also filled out questionnaires and were interviewed. Video cameras were used to follow the babies’ crawling activity, which began – on average – when they were seven months old.
Before the babies began to crawl, they woke up an average of 1.55 times a night, but when they got about on their hands and knees, they awakened 1.98 times per night. This change occurred more among babies who learned to crawl earlier than other babies their age and among those who learned later than usual, compared to babies with normal development. But the good news for parents is that the irregular sleeping caused by crawling ability will end three months later.
The researchers have a number of possible explanations for this phenomenon.
“It may be that crawling, which is connected to many changes involved in development and renewed psychological organization, raises the level of wakefulness and causes a period of instability that presents itself as waking up from sleep,” said Cohen. Another explanation is that crawling may cause anxiety in the child, who is exposed to new surroundings and can be physically separated from its mother at a time when its psychological resilience has not yet developed. “This anxiety can be expressed in irregular sleep patterns at night,” said Cohen.
EPIGENETICS & HOMOSEXUALITY Is homosexuality genetic? It’s a long-running debate. Now researchers at the University of Tennessee at Knoxville say they’ve found a clue that may unlock the mystery. It lies in epigenetics – how gene expression is regulated by temporary switches.
The researchers used mathematical modeling that found transmission of sex-specific “epi-marks” may signal homosexuality. Epi-marks constitute an extra layer of information attached to our genes’ “backbones,” that regulates their expression.
While genes hold the instructions, epi-marks direct how those instructions are carried out. They are usually produced anew each generation, but recent evidence demonstrates that they sometimes carry over between generations.
According to the study, published recently in The Quarterly Review of Biology, sex-specific epi-marks, which are “erased” and thus normally do not pass between generations, can lead to homosexuality when they “escape erasure” and are transmitted from father to daughter or mother to son.
“Previous studies have shown that homosexuality runs in families, leading most researchers to presume a genetic underpinning of sexual preference,” said Prof.
Sergey Gavrilets, a co-author of the paper. “However, no major gene for homosexuality has been found despite numerous studies searching for a genetic connection.”
It seems that epi-marks may be the trigger they’ve been searching for.
Sex-specific epi-marks produced in early fetal development protect each sex from the substantial natural variation in testosterone that occurs during later fetal development.
Different epi-marks protect different sex-specific traits from being masculinized or feminized.
The researchers found homosexuality can occur in opposite-sex offspring when the sex-specific epimarks are carried on to another generation.
“We discovered [that] when these epi-marks are transmitted across generations from fathers to daughters or mothers to sons, they may cause reversed effects, such as the feminization of some traits in sons, such as sexual preference and, similarly a partial masculinization of daughters,” said Gavrilets. “The study solves the evolutionary riddle of homosexuality, finding that ‘sexually antagonistic’ epi-marks, which normally protect parents from natural variation in sex hormone levels during fetal development, sometimes carry over across generations and cause homosexuality in opposite- sex offspring,” he explained.
The mathematical modeling demonstrates that gene coding for these epi-marks can easily spread in the population because they always increase the fitness of the parent but only rarely escape erasure and reduce fitness in offspring. “Transmission of sexually antagonistic epimarks between generations is the most plausible evolutionary mechanism of the phenomenon of human homosexuality,” said Gavrilets.
WELCOME, DOCTORS About 70 new immigrant physicians are joining the heath system – a help given the current serious shortage of MDs. The Immigrant Absorption Ministry has been working on a special project to encourage the immigration of Jewish physicians from the Diaspora. The doctors are given help in obtaining their medical licenses, learning regular and professional Hebrew and finding an employer. Once they are hired, the ministry pays the doctors’ first monthly paycheck.
ASPARAGUS FOR HANGOVER? You should never drink too much alcohol, but if you do, asparagus extract may help with the hangover.
According to a study published in the Journal of Food Science, the amino acids and minerals found in the vegetable may alleviate alcohol hangovers and protect liver cells against toxins.
Korean researchers analyzed the components of young asparagus shoots and leaves to compare their biochemical effects on human and rat liver cells.
“The amino acid and mineral contents were found to be much higher in the leaves than the shoots,” says lead researcher B.Y. Kim.
Chronic alcohol use causes oxidative stress on the liver as well as the unpleasant physical effects associated with hangovers.
“Cellular toxicities were significantly alleviated in response to treatment with the extracts of asparagus leaves and shoots,” said Kim. “These results provide evidence of how the biological functions of asparagus can help alleviate alcohol hangover and protect liver cells.”
Asparagus has long been used as an herbal medicine due to its claimed anti-cancer effects; it also is believed to have antifungal, anti-inflammatory and diuretic properties.