Monday, September 28, 2009

Beware of premature cornea ageing

A pair of contact lenses, positioned with the ...Image via Wikipedia


Neo Chai Chin

HERE's one more thing for contact lens wearers to be wary of - your corneas may be prematurely ageing.

Wearing contact lenses with low oxygen permeability for prolonged periods can damage the cornea, a transparent layer covering the eye. And the majority of Asians are using such lenses, said Australian eyecare expert Professor Brien Holden (picture).

This, in turn, may cause conditions like dry eyes, and cause the corneas to look "older" than normal. A sign of the latter is when the cells on the innermost layer of the cornea become varied in size - a condition called polymegethism, which is closely associated with corneal exhaustion syndrome, said Prof Holden of the University of New South Wales.

Cell density decreases with age, but studies have shown that a lack of oxygen accelerates the process. When that happens, a person may then have to cease wearing contact lenses altogether, he said.

Prof Holden, who is also chief executive of the Institute for Eye Research, an Australian company, was in Singapore yesterday.

"The first thing to do is to consult your local optometrist or ophthalmologist and talk to them about whether you are showing signs of excessive redness of the eye associated with low oxygen of your lenses, " he told Channel NewsAsia.

However, the "simplest thing" is to wear high oxygen permeable contact lenses or silicon hydrogel lenses, he said.

Singaporeans, it seems, are already making the switch.

Optometrists told Today of a rapid uptake since silicon hydrogel lenses became readily available four years ago.

President of the Singapore Optometric Association David Chong said over half his customers are using them. For optometrist Dr Koh Liang Hwee, the number is three in 10 monthly disposable lens users, and nine in 10 bi-weekly disposable lens users.

Silicone hydrogel lenses cost about 20 per cent more than regular soft lenses, they said.

To spread awareness, contact lens manufacturer Ciba Vision is launching a premature corneal ageing campaign this month.

A better alternative however, is to avoid wearing contact lenses altogether, said Dr Ray Manotosh of the Department of Opthalmology at the National University Hospital (corrected at 3:15PM, Sep 1).

"Contact lenses have many side effects (including) infection related to hygiene, and bacterial infection where you can lose your eyesight," he said.

Dr Manotosh added that compared with hard lenses (usually worn on doctor's prescription), the incidence of polymegethism among soft lens wearers is low.

But for those who insist on wearing contact lenses, "silicon hydrogels are the better lens, and the preferred lens should be those for daily wear instead of weekly or bi-weekly wear", he said.

From TODAY, Health – Tuesday, 01-Sep-2009

Knowing the signs will save your neck

Sagittal section of human vocal tractImage via Wikipedia

When seemingly trivial ailments such as a sore throat may mean cancer

Eveline Gan

THE sign seemed innocuous at first - a sore throat, which Mr L H Sim thought nothing of. But, unlike most sore throats, the discomfort didn't go away.

Mr Sim gradually lost his voice and appetite, too, which prompted him to seek medical attention.

A biopsy taken from a lump in his throat confirmed the 60-year-old car-cushion manufacturer's worst fears - he had third-stage throat cancer, a type of head and neck cancer.

The others in this category include cancer of the oral cavity, nasal cavity, throat, sinuses, larynx or voice box, thyroid and salivary glands.

Head and neck cancer afflicts about 500 Singaporeans each year, but the symptoms are hard to detect. That's because, like the case of Mr Sim, they seem to be trivial ailments.

A sore throat, stuffy nose or mouth ulcer might hardly be cause for alarm, but these could be signs of more insidious medical conditions.

To raise awareness of the disease, which is the sixth most common cancer to afflict men in Singapore, two public forums this Saturday will address issues and treatment options of the various forms of head and neck cancer (see health listings).

"Some of the early symptoms of head and neck cancer are similar to those of common ailments like upper respiratory tract infection and may be ignored," said medical oncologist Dr Leong Swan Swan, who had treated Mr Sim.

"This may cause delays in seeking medical attention and hence more advanced cancers at diagnosis," added the doctor, who is based at Gleneagles Medical Centre's Oncocare Cancer Centre.

About half of head and neck cancers occur in the mouth - mostly on the tongue, floor of the mouth and cheeks, said Assistant Professor Victor Fan, consultant at the National University Hospital's department of oral and maxillofacial surgery.


While a person with early-stage oral cancer may sometimes have no symptoms, a sign to look out for is a non-healing mouth ulcer, said Asst Prof Fan.

"The ulcers that most people get typically heal within 10 to 14 days. Any ulcer that doesn't heal in two weeks is suspicious," he added.

Other warning signs include a persistent sore throat or congested nose, as well as unusual lumps, and red or white patches in the mouth.

In more advanced cases, said Asst Prof Fan, the patient may have difficulty swallowing or slurred speech, especially those who have tongue cancer. Others may have abnormal lumps in the neck.

With many of head and neck cancer symptoms resembling common ailments, when should one sound the alarm?

"Symptoms due to common ailments should resolve spontaneously, or after medication. If they persist, it is always good to seek medical attention," said Dr Leong.

Head and neck cancers are usually diagnosed by specialists, such as an otolaryngologist or a head and neck surgeon, who may perform a biopsy on a suspicious lump or lesion. For oral cancer, a trained dentist can detect warning signs in the mouth, especially those in hidden corners.

With early diagnosis, head and neck cancers are curable, both doctors stressed.

Another plus point is that treatment of the early-stage cancer tends to be less traumatic for patients, said Assistant Prof Fan. The cure rate also drops dramatically if the cancer spreads to other parts of the body.

Traditional treatments involve surgery, radiotherapy or chemo-radiotherapy. According to Dr Leong, new options - such as drugs that target and destroy some types of cancer cells while causing little harm to normal cells - have become available for treatment.

After undergoing chemotherapy and radiotherapy, Mr Sim is now recovering. However, the side effect of his radiotherapy - which left him in excruciating pain and unable to eat or drink properly because his throat and neck were badly burned and scarred inside out - is something he will have to grapple with for a long time.

Quit smoking, drinking ... and chewing betel nuts

Research has found that smoking and alcohol consumption are two of the top causes of oral cancer, which forms about half of all head and neck cancer diagnoses.

According to Assistant Professor Victor Fan, your risk of oral cancer is six times higher than an average person if you smoke heavily, and up to 24 times higher if you smoke and consume more than 30 glasses of alcohol per week.

Other risk factors may be linked to heavy consumption of preserved foods such as salted fish, and viral causes such as human papillomavirus (HPV) infection and Epstein-Barr virus.

The chewing of betel nuts - which contains nicotine - may also increase the risk of cancer.

From TODAY, Health – Tuesday, 01-Sep-2009
In collaboration with Health Promotion Board

Tainted car seats a hazard

LEAD poisoning in children is usually traced to peeling paint in old homes or old lead pipes. But the family car, and the children's car seats, can also become contaminated, especially if parents work in jobs that expose them to lead.

When six babies and toddlers in Maine, in the United States, were found to have dangerously high levels of lead in their blood last year, public health workers tested the children's homes, but found no traces of lead except in some deck and outdoor areas where family members left their shoes and dirty clothes.
Then they tested the family cars.

"We consider levels of 40 microgrammes per square foot an elevated level for floors, which are a contact area for kids," said Ms Tina Bernier, an environmental specialist for Maine's Childhood Lead Poisoning Prevention Program.

"Some of the numbers in the car seats were in the 400 range, and it went up to 1,000 in other areas of the cars."

The parents of several children worked in removing paint from old buildings under renovation; three of them were employed by the same painting contractor, who did not provide workers with showers or places to change clothes before going home, as required, investigators said.

Another parent was a self-employed metal recycler.

The report, published last week in the Morbidity and Mortality Weekly Report for the Centers for Disease Control and Prevention, is the first known case of lead exposure through car seats, though lead has previously been found in cars. The New York Times

From TODAY, Health – Tuesday, 01-Sep-2009

Wednesday, September 23, 2009

Imaging tests increase risk of radiation damage

Radioactive hazard trefoilImage via Wikipedia

Doctors should weigh the benefits of medical imaging against the risk of cancer from cumulative exposures to radiation, as the use of the tests grows, researchers said.

Almost 70 per cent of around 950,000 patients surveyed underwent at least one imaging procedure, like a computer tomography scan, that exposed them to ionizing radiation over a three-year period, according to research published on Wednesday in the New England Journal of Medicine.

Low-dose radiation from medical imaging procedures has been linked to cancer, lead author Reza Fazel said. 

Doctors should prescribe tests only when the benefits outweigh the risks, he said. Researchers analysed data from 952,420 people who are part of United Healthcare Group's United Healthcare unit, estimating patients' radiation exposure based on the imaging procedures they were given.

"It is important to note that we are talking about radiation doses that are incurred in one year," said Brahmajee Nallamothu, a study author and cardiologist from the University of Michigan. "Cumulative doses over a lifetime may be much higher." BLOOMBERG

From TODAY, World – Friday, 28-Aug-2009

Did diet drug damage liver?

RofecoxibImage via Wikipedia

A late post, but something to be aware of concerning some drugs…


WASHINGTON - Health officials in the United States are investigating reports of liver injury in patients who took weight-loss drug Xenical and its over-the-counter version Alli.

The Food and Drug Administration (FDA) said on Monday they have received more than 30 reports of liver damage in patients taking the drug, which is known as Orlistat. The reports, submitted between 1999 and October 2008, included 27 hospitalised patients, and six who suffered liver failure.

Alli and Xenical are both marketed by British drug-maker GlaxoSmithKline, though Xenical is manufactured by Swiss firm Roche.

The FDA says it has not established a direct relationship between the weight loss treatments and liver injury, and advised patients to continue using the drugs as directed.

"Consumers should consult their health care professional if they experience symptoms," the agency said on its website. Signs of liver damage include fatigue, fever, nausea and vomiting.

The FDA said it is reviewing additional details about the suspected cases of liver injury submitted by manufacturers.

Roche referred questions to GlaxoSmithKline.

A spokeswoman for GlaxoSmithKline said there is no evidence the company's drug causes liver injury, noting that it primarily acts on the intestinal tract. She said Alli's safety has been studied in more 30,000 patients enrolled in 100 clinical studies.

"Liver changes can have many causes," said Ms Debbie Bolding, in a statement. "People who are overweight and obese are predisposed to liver-related disorders."

The FDA first approved Xenical in 1999 and Alli in 2007. The prescription pill is twice as potent as Alli.

In general, the FDA has started notifying the public earlier about possible safety issues with drugs, after coming under fire for acting too slowly on problems with blockbuster treatments like Merck's painkiller Vioxx. AGENCIES



Singapore HSA is monitoring Xenical probe

Singapore has two products containing Orlistat: Xenical which is prescription-only and the Xenical which can be dispensed under the supervision of a registered pharmacist.

Since 2000, the Health Sciences Authority has received four adverse reaction reports here that are suspected to be linked to Orlistat.

While two involved liver injuries, the link between the injuries and the weight loss drug could not be "conclusively established due to incomplete information and presence of confounding factors", said a spokeswoman.

Singapore has two products containing Orlistat: Xenical which is prescription-only and the Xenical which can be dispensed under the supervision of a registered pharmacist.

HSA said it will monitor the US FDA's investigation closely.

Meanwhile, patients may continue with the medication as directed by their doctors. But they should seek medical attention if they experience fever, fatigue, jaundice or nausea.

A spokeswoman for Roche said the company will continue distributing Xenical in Singapore: "Roche takes the issues of safety seriously and will continue to work with the health authorities closely."


Taken from TODAY, Health – Wednesday, 26-Aug-2009