HEALTH & FITNESS

Scientists create test-tube sperm
Breakthrough offers hope of finding cure for male infertility
Scientists have created human sperm in the laboratory for the first time. The extraordinary development, which until a few years ago belonged in the realms of science fiction, raises hopes that infertile men may one day be able to father their own biological children.

Coping with wisdom teeth
The third molars have been traditionally called “wisdom teeth” as these cut into the mouth at a time that coincides with the maturity of the person.  In fully-developed jaws, there are a total of three molars in each side of the upper and lower jaws. The first permanent molars erupt into the mouth at roughly six years of life. After its emergence, two more permanent molars make their appearance behind these teeth.   

Health Notes
n Fish oil for memory
n Diabetes danger

 

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Scientists create test-tube sperm
Breakthrough offers hope of finding cure for male infertility
By Jeremy Laurance

Scientists have created human sperm in the laboratory for the first time. The extraordinary development, which until a few years ago belonged in the realms of science fiction, raises hopes that infertile men may one day be able to father their own biological children.

The sperm were created in a test tube, from stem cells derived from a five-day-old male embryo. The advance raises ethical questions over the safety of the procedure and the threat it poses to the future role of men. It was also challenged by experts who claimed the sperm-like cells produced in the experiment were not genuine sperm.

If the finding is confirmed, a single male embryo could, in theory, yield a stem-cell line which when stored could provide an unlimited supply of sperm. Once the stem-cell line was established, there would be no further reproductive need for men. In a briefing on the research, the scientists at Newcastle University and the NorthEast England Stem Cell Institute, led by Professor Karim Nayernia, raise the question of whether their discovery means “the end of men”.

They point out that the stem cells from which the sperm were made could only be derived from a male embryo — one containing a Y (male) chromosome — so at least one male would be required.

“However, researchers believe that the issue does need to be debated and legislated for,” they said. “As work progresses and results improve at Newcastle and elsewhere it may, in theory, be possible to develop sperm from embryonic stem cell lines which have been stored.”

Professor Nayernia said: “In theory it would be possible (to dispense with men), but only if you want to produce a population all the same size and shape (because they have the same male genetic origin). Personally I cannot see human reproduction as purely a biological process. It has human, emotional, psychological, social and ethical aspects, too. We are doing this research to help infertile men, not to replace a reproductive procedure.”

The breakthrough was achieved using stem cells derived from a human embryo which were first developed into germ line stem cells — with half the number of chromosomes — and then prompted to produce sperm which were “fully mature and functional”, despite being made in a petri dish rather than the testes of a sexually mature man. The results are reported in the journal Stem Cells and Development.

In a parallel but incomplete experiment, the same group of researchers are creating stem cells out of skin cells from which they have produced sperm, with the same genetic make-up as the skin cells from which they are derived.This would allow infertile men to produce their own biological children, using only their skin cells. Professor Nayernia said the results of this research were “promising” and added: “We hope in a few months to publish that work as well.”

However, efforts to produce sperm from female stem cells failed. It had been thought the technique might allow lesbian couples to have their own biological children but the researchers say the genes on the Y (male) chromosome are essential to sperm maturation.

Three years ago, Professor Nayernia led scientists at the University of Gottingen in Germany who became the first to produce viable sperm from mouse embryonic stem cells which were used to produce seven live offspring. However, the baby mice died shortly after birth.

The latest discovery is a further step on the way to finding a cure for male infertility. Under current legislation, researchers are banned from using sperm (or eggs) produced in the laboratory – known as in-vitro derived (IVD) sperm — to treat patients. But it is permitted for research purposes.

“Sperm production takes 15 years in a human and there are thousands of factors that could affect it,” said Professor Nayernia. “We can investigate these factors in the laboratory in a matter of months with this technique.”

Experts yesterday challenged the Newcastle researchers’ claims to have created genuine sperm.

Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said: “As a sperm biologist of 20 years’ experience, I am unconvinced from the data presented in this paper that the cells produced ... can be accurately called ‘Spermatozoa’.”

Azim Surani, a professor of physiology and reproduction at the University of Cambridge, said: “These sperm-like cells made in a dish from embryonic stem cells are a long way from being authentic sperm cells.” Professor Robin Lovell Badge, from the National Institute for Medical Research, echoed the academic criticisms, but said: “Despite these drawbacks, it may be that the authors have made some progress in obtaining sperm from human embryonic stem cells in vitro.

“This will be very important for research and ultimately, although definitely not yet, for fertility treatments.”

Professor Nayernia said his research was submitted as “proof of principle” which needed confirmation by further studies. “Our intention was to open up new avenues of research,” he said. “It seems unreasonable to criticise our work on the basis that we have not done more.”

The Human Fertilisation and Embryology Authority, which regulates research, has estimated that it will be at least five or 10 years before eggs of sperm could be produced which could potentially be used in treatment.

Before laboratory-produced sperm could be used to make babies for couples who are infertile, the 2008 Human Fertilisation and Embryology Act would have to be changed.

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Coping with wisdom teeth
Dr H.S. Chawla

The third molars have been traditionally called “wisdom teeth” as these cut into the mouth at a time that coincides with the maturity of the person.  

In fully-developed jaws, there are a total of three molars in each side of the upper and lower jaws. The first permanent molars erupt into the mouth at roughly six years of life. After its emergence, two more permanent molars make their appearance behind these teeth.   

The second permanent molars cut in at about 12 years of age. The eruption of the first and second molars generally escapes attention because these do not cause pain. In fact, none of the permanent teeth cause any untoward reaction during eruption. 

The emergence of the third permanent molars — or wisdom teeth — causes problems in some individuals. The wisdom teeth, one in each jaw, erupt into the mouth behind the second molars between 18—21 years in well-developed jaws. These are the last permanent teeth to cut into the mouth. The emergence of third molars in the jaws occasionally causes pain and sometimes swelling of the soft tissue overlying these teeth. These problems are more frequently associated with lower wisdom teeth.  

Why does the eruption of wisdom teeth cause pain and discomfort? 

With the change of our diet from coarse and fibrous food to soft food due to the advances in civilization, the size of the jaw has become smaller over the years, whereas the size of the teeth has not reduced — kept pace with evolution.

Since the third molars —wisdom teeth— are the last teeth to erupt in the mouth, the brunt of the lack of space in the jaw falls on these teeth. It is like the last person entering a bus with all seats occupied. Either this person has to be sent out or squeezed in. The third molars, likewise, when trying to cut into the limited space, either cannot physically emerge into the mouth or their path of eruption gets deviated and they come out tilted. These teeth may erupt bent mesially, distally, bucally or lingually, or in a combination of these directions.  

The wisdom teeth thus exert tremendous pressure on the other teeth while erupting, and pain ensues.  

Another problem that is encountered is the swelling of the soft tissue that overlie the erupting lower third molar. It is technically called ‘Pericoronitis’. This is encountered particularly in cases where the eruption of upper wisdom tooth has preceded the eruption of the lower wisdom teeth. The soft tissue overlying the lower tooth gets a little inflamed due to erupting pressure of the molar. If it further gets stoked by the already erupted upper molar, the local inflammation is markedly aggravated, and a vicious cycle sets in. In these cases, the extraction of the upper molar eases the pain. 

The pain that comes during the active phases of eruption of wisdom teeth is temporary and would subside after a little time, i.e., once the active period of growth subsides. The pain due to inflammation of soft tissue overlying the molar will subside only with releasing of pressure of opposing tooth by extraction of the offending third molar. The grinding of the upper molar causing trauma to the soft tissue would give temporary relief. If the soft tissue catches infection, antibiotics are required. 

When should a wisdom tooth be got extracted? 

It warrants extraction if i) there are recurrent episodes of pain and discomfort, ii) it is partially erupted and impacted, iii) is causing food impaction, iv) despite your best efforts, you can not keep it clean, v) it has caused or is likely to cause dental cavity in its own hard structure, or that of the tooth in front of it, vi) there is overcrowding in the anterior region as the  wisdom tooth’s pressure is likely to increase the overcrowding, and vii) there are signs of cheek bite due to its mal-positioning. 

Would extraction loosen other teeth? 

There is a common notion that extraction of the wisdom tooth will loosen the rest of the teeth. But it is not so. All the teeth in both upper and lower jaws are naturally forwardly inclined and exert a mesial pressure.  

When the wisdom tooth was present, it was the last tooth. When it is extracted the tooth in front will now become the last. So there will always be a last tooth in the arch without support from behind. 

The writer, Head of the Dental Department, The Apollo Clinicx, Chandigarh, is a former Head, Oral Health Sciences Centre, PGI, Chandigarh. Email: chawlahs@gmail.com

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Health Notes
Fish oil for memory

London: A study carried out by American bioscience company Martek suggests that taking fish oil supplements can reduce memory loss in old age. Dr Karin Yurko-Mauro, a researcher associated with the company, has revealed that taking a supplement of Omega 3 for six months had a beneficial effect on people with age-related forgetfulness and loss of learning ability during the study. According to the study report, taking 900mg capsules every day was found to be the equivalent of turning back the clock three years. The researchers hope that future studies will provide promising results suggesting that the fatty acid may help stave off Alzheimer’s disease, if new techniques can be found to diagnose it before it take holds.

Diabetes danger

London: Middle-aged men are almost twice as likely to have diabetes compared to their female counterparts. A report from the health charity Diabetes UK found that cases of diabetes have risen four times faster in men aged 35 to 44 over the last 12 years compared with women of the same age. Over that time, men have consistently been more overweight than women, which is fuelling their higher rates of Type 2 diabetes. This type is associated with unhealthy lifestyles, including a lack of exercise and obesity, and accounts for around nine out of 10 cases of the disease. On contrary, the other sort of diabetes, Type 1, is not linked to obesity and usually develops in childhood or adolescence. — ANI

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