Sept 21 is World Alzheimer's day:

Alzheimer's disease rampant in our ageing population

By Nilma DOLE

The nuclear family concept in Sri Lanka has been a traditional part of our culture for years but today, young Sri Lankan couples are quick to put their elderly parents in homes or leave them in a hospital until their dying day. Every person who retires longs to age gracefully and lead a quiet and rewarding retirement life but what happens when they are no longer loved or cared by their own children?

What is unfortunate is that private health companies, hospitals and care-givers are now making money by offering their services, building hostels and getting their children to put their own parents in elder's homes so that they can make money.

Presidential award winning researcher and member and head of several organisations working in brain development and neurology, Prof. Ranil de Silva of the Sri Jayawardenapura University has done extensive research into Sri Lanka's ageing population. In his research, for the past ten years, the elderly population living in developing countries has increased by 200 to 280 percent compared with a mere 30 to 40 percent increase in the developed nations.

Of the world’s 580 million elderly that is over the age of 60, 335 million which amount to 61 percent, live in developing countries. A World Bank report on Sri Lanka’s ageing population has revealed that the country is rated as the fastest aging population in South Asia.

According to Prof. de Silva, the demographically ageing population will place an additional strain on the Sri Lankan economy and health sector, which was affected by terrorism and a growing number of displaced persons. In a survey done by the Health Ministry, Sri Lanka's declining birth rate, with the high life expectancy of 74.1 years, has led to an increase in the ageing population in Sri Lanka.

Prof. de Silva said, “Sri Lanka's segment of the population over 60 years in 2000 was 9.2 percent which will reach almost 30 percent by 2050.” This statistic is the highest estimated value for South-Central Asia and the second highest for South East Asia.

In Sri Lanka, the increasing ageing population has led to the decrease in traditional family support and increase in institutionalised for elderly people. When children go abroad to better their lives, the quality of life of their own parents is not fruitful. According to the professor, there has been an increase in the number of public care homes for elders under the Department of Social Services in Sri Lanka from 68 homes in 1987 to 162 homes in 2003 (this number excluding paying homes).

If there are no means of helping Sri Lanka's ageing population in the future, our health budget will be in jeopardy to support for all those with Alzheimer's disease, Parkinson's disease and vascular dementia.

“We are sitting on a time-bomb and if nothing is done to take control of the situation, we will waste money and resources on trying to give support, help and care to Alzheimer patients,” said Prof. de Silva.

At present, there is insufficient data to accurately determine how many Alzheimer patients are there. “Data in Sri Lanka on such topics is not accurate and more research and development needs to be done on finding out the exact situation,” he said. Moreover, Sri Lanka's culture is rapidly changing to Western habits which means that not only do we eat unheathily, we have shunned our traditional culture in favour of a modern one.

“As a result of lack of a proper diet, poor exercise and Western habits we are now on the verge of becoming a population ridden with disease at a young age including Alzheimer's Disease,” said the professor. According to the professor, of the Alzheimer's patients, 75 percent is caused by dementia, 25 percent by vascular strokes and three percent by Parkinson's disease. He said, “There will be 81 million new cases of dementia in the next few years prevalent in developing counties and 4.6 cases of dementia arising every day in the Asian region.” Prof. de Silva said that a regional community survey of people over 65 years in Sri Lanka showed a dementia prevalence of 4 percent.

It has also been found that those in elder's homes are more prone to having a higher prevalence of cognitive impairment than those who are still living in the community.

The bottom line is that our ageing population is growing at an alarming rate and there is not enough infrastructure to give additional support to such patients.

While the public sector has a difficult time trying to help elderly victims who are impaired, the private sector reaps profits with those in hostels and elders homes. As a result when these elderly people are institutionalised and sent to elders homes, they sit there doing nothing.

They are seen as of no use to society, they don't use certain regions of their brain to do mathematical activities or use creative intelligence, and they quick forget. As a result these conditions make the elderly susceptible to conditions such as dementia, Parkinson's disease and Alzeimer's.Prof. de Silva said, “There is no cure for Alzheimer's disease unless of course research is done into prevention it.

However, pharmaceutical companies around the world are trying to formulate a wonder drug to cure it to no avail and make billions from long-suffering victims and their families.” Even if it is difficult to get elderly people to work or still wait in employment, there needs to be alternative ways for them to be a benefit as opposed to a burden in society.

Hence, it is imperative to ensure that the public and private health sectors ensure that there is a better tomorrow for our senior citizens if we don't want Alzheimer's to be an nation-wide epidemic.

Depression in adolescents

by Dr. R. A. R. Perera

Depression is now recognised as one of the most serious global public health problems and is predicted to become the second leading cause of disease burden worldwide by the year 2020. Untreated depression has a significant effect on a young person's development and functioning in all areas of their lives and early case identification and intensive treatment of first episodes of depression will reduce prevalence, cost and hospital admission.

Adolescent depression is not expressed as a single symptom but as a cluster of symptoms that may include the features of depression in adults.

Depressed adolescents are also likely to present with symptoms that are more specific to their development stage. Depression in adolescents might show characteristics such as

* Irritability of mood
* Eating disturbance and failure to make expected weight gain
* Diminished school performance and unexplained boredom
* Lowered self esteem and self criticism
* Self destructive impulses and risk taking
* Anxiety and tearfulness
* Unexplained aggression, social withdrawal from friends and usual activities
* Fatigue and somatic complaints
* Substance abuse

Depressive symptoms range from mild to severe. In mild forms, depression can be a self-limiting condition associated with spontaneous remission and in more severe forms it is associated with suicidal behaviour. Adolescents experiencing a depressive episode are highly vulnerable to experience further episodes throughout their lifetime and in many individuals, depression shows a worsening pattern over the course of repeated episodes characterised by increased severity and frequency.

In Sri Lanka, the prevalence of depression is increasing and up to 24 pc of adolescents will have had major depression by the age of 18. There is a higher prevalence of adolescent mental health problems among those living in low income, and sole parent families.

The prevalence of depression in childhood is approximately 2pc and then rises to approximately 5pc from the ages of 9-19. Adolescent girls are twice as likely to suffer from depressive symptoms.

The reasons for the sex difference are unclear but genetic factors; hormone effects, socialisation and histories of sexual abuse may contribute to this gender difference.

Depression may manifest in a number of ways including relationship problems with family and peers, due to irritability or social withdrawal. Failing ability to function within family, school or other usual situations in a previously well functioning young person is a serious warning sign. The assessment of adolescent depression also involves exploring the

* Cause and precipitating factors
* Duration of the disorder
* Risk factors and suicidal intent

Genetic factors play a big role in causing adolescent depression. Depression may be precipitated by stressful events at home (marital problems, parental divorce) or school (academic difficulties, peer rejection). Uncaring or over controlling parenting is also associated with depressive disorder in adolescents. Better assessment and management of the most salient risk factors may prevent or reduce the duration of depression. The severity of depression has been found to be significantly associated with longer duration and with greater likelihood or recurrence.

Factors associated with persistent depressive symptoms are

* Poor general health and female gender
* School suspension
* Weaker family relationship
* Refusal or inadequate treatment

Treatment

Cognitive behavioural therapy is a treatment of first choice. But this is more suitable in mild and moderate depression. There is growing evidence that other psychotherapies, such as interpersonal therapy, and family therapy are also effective.

Antidepressant drugs are useful in severe depression. However cognitive therapy is effective in approximately 65pc cases compared with 50pc cases treated with drugs.When long-term outcome for depression is considered, it appears that cognitive therapy is more effective at preventing relapse, and more cost effective than drugs.

Interpersonal therapy, which involves systematic identification and resolution of relationship problems and family therapy, which reduce family dysfunction and conflict, are the other two useful methods in reducing depression in adolescents.

Successful management may involve combination of above treatments and a multidisciplinary team approach including school counselors, psychologists and social workers.

The writer is a Consultant Psychologist

Ants have an exceptionally ‘Hi-Def’ sense of smell

Ants have four to five times more odor receptors than most other insects, a team of researchers have discovered.

The research team, led by Lawrence Zwiebel at Vanderbilt, recently completed the first full map of olfactory system that provides ants with their sense of taste and smell.

They found the industrious insects have genes that make about 400 distinct odorant receptors, special proteins that detect different odors.

By comparison, silk moths have 52, fruit flies have 61, mosquitoes range from 74 to 158 and honeybees have 174.

“The most exciting moment for me was when the analysis came back showing that we had identified more than 400 OR genes, the largest number of any known insect species,” said Xiaofan Zhou, the research associate who headed up the characterisation process. “It meant that we had successfully taken the first step toward gaining a new level of understanding of the complex social system that has made ants one of the most successful families on the planet.”

People have long been intrigued and inspired by ants’ ability to form highly organised colonies with division of labour, communication between individuals and ability to solve complex problems. For some time, scientists have also known that chemical communication plays an important role in ant behaviour. “So it's a reasonable supposition that this dramatic expansion in odour-sensing capability is what allowed ants to develop such a high level of social organisation,” said Laurence Zwiebel, professor of biological sciences, who directed the new study published in the August. 30 issue of the journal PLoS Genetics.

Zwiebel's team characterised the olfactory systems of two distinctly different ant species as part of an interdisciplinary project titled “Epigenetics of Behaviour, Longevity and Social Organisation in Ants,” headed by Danny Reinberg of New York University and funded by the Howard Hughes Medical Institute.

In 2010, the project sequenced the genomes of the two species - the Florida carpenter ant (Camponotus floridanus) and the Indian jumping ant (Harpegnathos saltator) - for the first time.

This effort set the stage to make the detailed olfactory study possible.

The olfactory system of most insects is centered in their antennae and is broadly made up of three different classes of receptors: odorant receptors (ORs), that identify different aromatic compounds and pheromones; gustatory receptors (GRs), that distinguish between different tastes and react to some pheromones; and newly discovered ionotropic glutamate receptors (IRs),that are narrowly tuned to various poisonous and toxic compounds.

The study found that the primary expansion in the ant's olfactory system is focused on ORs. The number of GRs and IRs are comparable to those found in other insects.

The initial automated analysis of the two ant genomes found only about 100 genes for ORs and ten GRs.

“We knew these numbers were low because olfactory receptors are very difficult to identify,” Zhou said. So he and his colleagues designed a novel automated bioinformatic process for this purpose, combined with extensive manual evaluation.

The researchers also compared both the identity and expression levels of ORs in the two species and found significant differences.

This wasn't surprising because the two species were selected to reflect the high level of diversity that exists within the ant family. Carpenter ants live in large colonies with long-lived queens that produce all the fertilised eggs.There are two castes of sterile workers. When the queen dies so does the colony. Jumping ants, by contrast, live in small groups, the difference between the queen and workers is limited, and some workers can mate and lay fertilised eggs.

“The differences in receptors are most probably associated with the difference in lifestyles of the two species,” Zhou said.

Similarly, their analysis found important differences in the ORs in the antennae of males and females.

Overall, they found that the males have only one third the number of ORs that the females express.

“The primary role of males is fertilisation of eggs, so we assume that the ORs that males express and that females don't are probably tuned to pheromones produced by the queen,” Zhou said.

The team also took the initial steps in identifying the chemical signals that set off specific ORs.

Research Associate Jesse Slone adapted an assay that the group initially developed for matching ORs with chemical signals in the malaria mosquito.

The assay involves inserting the gene for a receptor into frog eggs so that the receptors are expressed on the egg's surface.

By wiring the eggs and then exposing them to different chemical compounds, the eggs produce a measurable electric signal when the receptor is activated. Slone used this assay to identify the compounds that trigger one OR on each of the ant species.

He found that an aromatic compound found in anise triggered the OR from the jumping ant that he tested.

The receptors were found in both males and workers.

Since studies have shown that anise oil has a repellant and/or insecticidal effect on some species of insects, the compound may be a general insect repellent that this OR is designed to detect, Slone speculates.

By comparison, the OR from the carpenter ant turned out to react to a naturally occurring odorant found in cooked beef and pork.

The scientists have no idea why this compound is relevant to the ants, but they did establish that the specific receptor is enhanced in workers, relative to males.

“This is just the beginning. But we have demonstrated that we have the basic tools we need to act as ‘OR detectives’ to map the ants ‘odour space’ and identify the chemical signals that trigger specific behaviours in the ant's extensive repertoire,” Slone said.

This represents the opening of a major new research avenue for the Zwiebel Lab, which has been focused on pioneering work deconstructing the olfactory system of the malaria mosquito.

“When I was in graduate school, a group of us dreamed about deciphering the role that genes might play in ant social behaviour.

So I couldn't pass up this opportunity when it came along.

It's taken 30 years but we've finally got to the point where we can actually do these studies.”

- MNT