In a new study published in Disease Models & Mechanisms, scientists use the zebrafish to gain insight into the influence of known cancer genes on the development and progression of melanoma, an aggressive form of human skin cancer with limited treatment options.

Inside the cell, signals are delivered that direct the cell on whether to divide, migrate or even die. Cancer often results when the molecules that relay these signals become mutated so that they do not function normally. In cancer, cells divide, grow and migrate when they should not, therefore resulting in an aggressive disease that can spread throughout the body. A key molecule in this signaling pathway is RAS, and mutations in it are known to lead to cancer. In some cases, the type of RAS mutation is a predictor of a patient's response to treatment and their overall prognosis.

Therefore, scientists at the University of Manchester in England and the University Hospital Zürich in Switzerland generated several zebrafish with changes in RAS or other RAS-regulated proteins to create a useful model that can be used to study and understand human melanoma. Zebrafish are a useful tool to understand human disease because they are small, transparent, and easy to propagate and maintain. Tumors created from the pigmented cells of zebrafish, known as melanocytes, are easy to see against their thin, light colored bodies.

The research team notes that these fish may be a useful experimental tool for human disease. Many of the changes they made caused melanoma in the zebrafish, indicating that zebrafish respond similarly to changes in these signals as do humans. Zebrafish that were born from the original mutant fish displayed abnormal growth of their melanocytes, reminiscent of familial atypical mole and melanoma syndrome (FAMM) seen in humans. By producing other signaling molecules in the mutant fish, the researchers were able to identify a pathway that reduced the effects of RAS mutations on melanoma progression in zebrafish.

The relationship between the dental disease periodontitis and coronary heart disease (CHD) has been known for several years. Although a genetic link seemed likely, until now its existence was uncertain. Now, for the first time, scientists have discovered a genetic relationship between the two conditions, a researcher told the annual conference of the European Society of Human Genetics.

Dr. Arne Schaefer, of the Institute for Clinical Molecular Biology, University of Kiel, Germany, said that his team had discovered a genetic variant situated on chromosome 9 which was shared between the two diseases. "We studied a genetic locus on chromosome 9p21.3 that had previously been identified to be associated with myocardial infarction, in a group of 151 patients suffering from the most aggressive, early-onset forms of periodontitis, and a group of 1097 CHD patients who had already had a heart attack. The genetic variation associated with the clinical pictures of both diseases was identical," he said. The scientists went on to verify the association in further groups of 1100 CHD patients and 180 periodontitis patients.

"We found that the genetic risk variant is located in a genetic region that codes for an antisense DNA called ANRIL", said Dr. Schaefer, "and that it is identical for both diseases."

When a gene is ready to produce a protein, the two strands of DNA in the gene unravel. One strand produces messenger RNA, and will express a protein. Antisense RNA is complementary to the mRNA, and is often carried by the reverse strand, the 'anti-sense' strand of the DNA double helix. This strand does not encode for a protein, but can bind specifically to the messenger RNA to form a duplex. Through this binding, the antisense strand inhibits the protein expression of the mRNA .

Coronary heart disease is the leading cause of death worldwide, and periodontitis, which leads to the loss of connective tissue and the bone support of teeth, is the major cause of tooth loss in adults over 40 years. Periodontitis is very common, and around 90% of people aged over 60 suffer from it. Research has already shown a genetic basis for both diseases.

"We intend to push ahead with our work to try to understand more about the function of this RNA molecule and the pathway in which it operates in healthy gums and also in periodontitis. In the meantime, because of its association with CHD, we think that periodontitis should be taken very seriously by dentists and diagnosed and treated as early as possible", said Dr. Schaefer.

Both CHD and periodontitis are propagated by the same risk factors - most importantly smoking, diabetes and obesity - and there is also a gender relationship, with men possibly more liable to these diseases than women. Researchers have also shown similarities in the bacteria found in the oral cavity and in coronary plaques, and both diseases are characterised by an imbalanced immune reaction and chronic inflammation.

Spring cleaning? While clearing out cobwebs and boxing up old clothes, don't forget an invisible but crucial component of your home: the air you breathe. Even in the spring, people spend most of their time indoors-as much as 90 percent, according to the Environmental Protection Agency (EPA). For those with allergies or asthma, having clean indoor air is crucial to managing symptoms.

Allergy & Asthma Network Mothers of Asthmatics (AANMA), the sole organization whose mission is to eliminate suffering and death due to asthma, allergies and related conditions, gives you five tips for spring-cleaning the air in your home to make it lung-friendly by reducing allergens and irritants.

1. Smoking: Ask family members or visitors not to smoke in your home. Consider having your family take the EPA Smoke-Free Home Pledge.

2. Mold: Search under sinks, around tubs and showers, on windowsills and in laundry areas for any signs of dampness and mold. Track the source of water, plug it up and clean up visible mold. Purchase and use a dehumidifier in basement areas.

3. Air it out: Give your bedroom a thorough airing out-wash curtains, linens and bedspreads, and make sure to clean anywhere dust and allergens collect.

4. Use a HEPA vacuum: If you don't have one already, consider getting a HEPA (High Efficiency Particulate Air) vacuum. These vacuums have special filters that keep dust and allergens from blowing back into the air in your home.

5. Replace HVAC filters: Replace your furnace filters before air-conditioning season. And since the filter that comes with your HVAC (heating, ventilating and air conditioning) system isn't designed to help you breathe better (it simply keeps dust and debris from clogging parts of the system) look into a high-efficiency filter or an air-cleaning unit.

The FDA (Food and Drug Administration) has approved Samsca (tolvaptan), in tablet form, for the treatment of hyponatremia. Hyponatremia is when levels of sodium in the blood are abnormally low - it is associated with dehydration.

Norman Stockbridge, M.D., Director, Division of Cardiovascular and Renal Products, Center for Drug Evaluation and Research, FDA, said "With the approval of Samsca, physicians will have an additional tool to treat hyponatremia."

Samsca is approved to treat hyponatremia associated with congestive heart failure, liver cirrhosis, and the syndrome of inappropriate antidiuretic hormone secretion.

When levels of sodium fall in the fluid outside of cells throughout the human body, water enters the cells to balance sodium levels - this makes the cells swell. Many symptoms of hyponatremia are thought to arise from the swelling of the brain cells, the FDA informs. Symptoms include:

* Headache
* Weakness
* Confusion
* Decreased consciousness
* Nausea

Samsca removes extra body water in the urine, thus helping raise sodium levels in the blood. In clinical trials, participants taking Samsca had higher increases in blood sodium levels compared to participants receiving a placebo (dummy drug).

The approval of Samsca includes a boxed warning that alerts doctors, pharmacists, other health care professionals, and patients that the medication should be started only in a hospital where blood sodium levels can be monitored carefully. If blood sodium levels rise to quickly there is a risk of osmotic demyelination syndrome (ODS). ODS can lead to coma, and even death. It can cause the patient to have problems speaking, swallowing, as well as causing drowsiness, confusion, mood changes, seizures, and problems controlling body movement with muscle weakness in the limbs.

Even though there were no cases of ODS detected during the clinical trials of Samsca, ODS is a known risk and it is crucial that doctors be aware of it, and make sure rapid increases in sodium levels do not occur, the FDA said. In addition, the FDA is requiring a Risk Evaluation and Mitigation Strategy that requires a patient Medication Guide be given when the drug is dispensed. The Medication Guide will have information about the risks and benefits of the drug.

During the clinical trials, the following side-effects were reported by participants: thirst, dry mouth, weakness, constipation, excessive urination, frequent urination, and raised blood sugar levels.

A new study suggests that by 2010, India's death toll due to tobacco smoking will be about 1 million people a year (10 lakh in Indian counting system), taking the country's smoking epidemic to catastrophic proportions. This figures will represent one fifth of deaths in men and one twentieth of deaths in women aged 30 to 69, with smoking causing deaths from tuberculosis, respiratory disease, cardiovascular disease, and cancer.

There are about 120 million (12 crore in Indian counting system) smokers in India. About 5 per cent of women and more than one third of men aged between 30 and 69 smoke either conventional cigarettes or bidis, a type of Asian cigarette made from one quarter of the tobacco content of a conventional cigarette and wrapped in the leaf of a temburni plant.

The researchers calculated that on average in India, compared with non smokers, men who smoke bidis die about six years earlier, women who smoke them die about eight years earlier, and men who smoke cigarettes die about 10 years earlier (about the same as in the West).

Even low levels of smoking were not found to be safe, wrote the researchers. Smoking a few bidis a day brought substantial risks, and smoking a few cigarettes a day brought even more, to the point of doubling the risk of death in middle age, they wrote.

India's Health Minister, Dr Abumani Ramadoss, said he was alarmed at the results of the study, and that:

"The government of India is trying to take all steps to control tobacco use; in particular by informing the many poor and illiterate of smoke risks."

Professor Prabhat Jha of the Centre for Global Health Research (CGHR), St. Michael's Hospital at the University of Toronto in Canada, who led the study said:

"The extreme risks from smoking that we found surprised us, as smokers in India start at a later age than those in Europe or America and smoke less. And, smoking kills not only from diseases like cancer and lung diseases but also from tuberculosis and heart attacks."

The large study employed some 900 field workers to carry out a nationally representative survey of 1.1 million (11 lakh) homes throughout India. From this the researchers were able to compare the smoking histories of 74,000 adults who had died (33,000 women and 41,000 men) with 78,000 living unmatched controls (35,000 women and 43,000 men). They then worked out the risk ratios for death comparing smokers and non smokers and adjusted them for age, educational level, and alcohol consumption.

The results showed that among men who died at ages 30 to 69, smoking was responsible for:

* 38 per cent of all deaths from tuberculosis (1,174 deaths out of 3,119).
* 31 per cent of all deaths from respiratory disease (1,078 of 3,487).
* 20 per cent of all deaths from vascular disease (1,102 of 5,409).
* 32 per cent of all deaths from cancer (709 of 2,248).
* 23 per cent of all deaths from any disease (5,651 of 25,290)

Jha and colleagues found that 61 per of male smokers are likely to die between the ages of 30 and 69 compared with only 41 per cent of their non smoking counterparts. For women the researchers calculated the figures to be 62 per cent can expect to die in the age range 30 to 69 compared with only 38 per cent of their non smoking counterparts.

The study also found that:

* Smoking 1 to 7 bidis a day raised risk of death by one-third, and smoking 1 to 7 cigarettes a day nearly doubled it.

* Smoking is responsible for most of the gap between male and female rates of death in middle age.

* The risks were significant among both educated and illiterate adults, in both urban and in rural areas.

* Quitting smoking works, but only 2 per cent of adults in India have quit, mostly after falling ill.

Professor Amartya Sen, well known Indian economist and philosopher who won the Nobel Prize for Economics in 2001, said:

"It is truly remarkable that one single factor, namely smoking, which is entirely preventable, accounts for nearly one in ten of all deaths in India."

He said that the study "brings out forcefully the need for immediate public action in this much neglected field".