Wednesday, 17 February 2016

The Zika Virus

The Zika virus epidemic  has been declared an International Emergency by the World Health organization on the 1st February. The infection has spread rapidly and is now threatening to spread to other regions of the world.

The Zika virus has been associated with two dangerous medical conditions:

(a)    Microcephaly: This is a condition in which the size of the head is distinctly smaller than normal. It occurs when the brains fails to grow and mature  during fetal life. Since the brain does not grow, the skull does not grow either. The baby may have  severe developmental anomalies, seizures, mental retardation, problems with muscular co-ordination and gait, difficulty in moving the eyes, lips, facial muscles etc.


It has not yet been conclusively proved that the Zika virus causes microcephaly but the incidence of microcephaly has shot up in areas with the Zika virus epidemic and this has been considered serious enough for health authorities to advise women not to get pregnant  in those areas. Zika infection in the first trimester is considered more risky than at other times in pregnancy.

(b)    Guillan barre Syndrome (GBS): This is an autoimmune condition in which the immune system of the body attacks the nervous system leading to inflammation of the nerves with paralysis of the muscles. It occurs in adults. It starts with tingling and numbness of the fingers and toes followed by weakness of the muscles of the arms and legs. The weakness gradually spreads all over the body.  If the respiratory muscles  are affected, there may be  acute difficulty in breathing. Mortality rate is high.

Spread of the Zika virus:

 The Zika virus is spread  through the bite of a  mosquito known as the Aedes mosquito. This is a daytime mosquito found mainly  in urban and semi-urban areas. It has typical white markings on its legs and body. It lays eggs in stagnant water in pots and containers around the house. It needs human blood to get nutrients for growth of the eggs.

Symptoms of Zika virus

The first symptom occurs about 2-7 days after  the bite of an infected mosquito.

-          In many cases, there may be no symptoms at all. Or the symptoms may be so mild  that the patient does not realize that she is infected. These people can then become carriers of the disease.

-          The early symptoms  are  fever, bodyache, headache muscular aches, conjunctivitis (pink eye)  and a rash over the body.

-          There may be a general feeling of ill health.

-          Symptoms may linger for days before clearing up spontaneously.

The Zika virus can be diagnosed by  the presence of the virus in the blood (virological test) or by the presence of antibodies to the virus(serological tests). The virological test is positive in the first 3-5 days of infection. The serological tests are positive after the first 5 days.


-          There is no specific treatment for Zika. Medicines are prescribed  for  symptomatic relief .
-          Painkillers like acetaminophen or paracetamol to manage the aches and pain. NSAIDS like ibuprofen and Naproxen should  not be taken as they increase the risks of bleeding.
-          Adequate fluids should be taken to overcome dehydration
-          Rest
-          It is best to avoid getting pregnant  if a case of Zika is diagnosed in the locality. Contraceptives should be used.
-          At present there are no vaccines for Zika.  A  vaccine (‘Zikavac’) is under production in India   and is at the stage of animal trials.


The infection can be prevented by (a) preventing breeding of  mosquitoes in  and around the house (b) avoiding mosquito bites.

a)      How to prevent breeding of mosquitoes
-          Drain out and remove anything around the house that can collect stagnant water, e.g. flower pots, bottles, drinking bowls of pets etc.
-          Cover water tanks
-          Attach mosquito screens over doors and windows.
-          Clear away all collected garbage, including that around nearby eateries and restaurants.

b)      How to prevent mosquito bites
-          Wear long sleeved shirts and/or blouses at all time, especially during the day since the Aedes mosquito is a daytime biter.
-          Use mosquito repellents.
-          Use mosquito nets.

Friday, 24 July 2015

Medical Ultrasonography

Medical Ultrasonography is a medical diagnostic technique used to visualize inner body  structures like muscles and other soft tissues as well as  organs like the liver, gallbladder and various other  structures.  It helps to identify  any pathology in the tissues   and record any lesion.

The Ultrasound Machine

The word ‘ultrasound’ refers to sound waves  with a frequency too high for human ears to hear. In medical ultrasound, sound waves  in frequencies ranging from 1.6 to 10 megahertz are employed. Superficial structures like muscles, tendons, thyroid etc  are at a higher frequency (7–18 MHz) while deeper structures such as the liver and kidney are imaged at a lower frequency 1–6 MHz.

Ultrasonography  utilizes sound waves which are  sent into the body in pulsatile waves with the help of a transducer or probe. The sound waves bounce off the structures and the echo is received  by the probe and displayed on screen on a monitor.

Ultrasonography used during pregnancy to monitor the growth and health of the fetus  and other pregnancy tissues like the placenta and amniotic fluid is known as Obstetrical ultrasound and is widely used. Nowadays, it is a routine procedure performed in all pregnancies in the first trimester  to help identify any anatomical defects in the fetus.

Ultrasonography is also used  as an aid in  treatment procedures – for example,  draining of fluid or pus or in ultrasound guided biopsies. This procedure is known as interventional ultrasonography.
Other types of ultrasonography include cardiac ultrasonography (echocardiography), dental ultrasonography, Doppler ultrasonography to study blood flow and muscle motion as well as high intensity focused ultrasonography. Lithotripsy , a procedure used to break up kidney stones is a type of high intensity focused ultrasonography.

Compared to other medical devices, ultrasound has many advantages – it is safe because it does not use any ionizing radiation, the device is portable and can be easily carried to the patient’s bedside,  it is not very expensive and the results are obtained in real time, meaning that the result is available instantly at the time of the test and the patient does not need to wait for a long time for the report to be available.

The main disadvantage of ultrasound is that it requires a skilled operator  for an accurate report. Another disadvantage is that structures behind bones may not be readily seen.

Ultrasonography is one of the most widely used diagnostic aids in medical care today.

Monday, 8 June 2015

How Life Began on Earth

Life on earth began in a primordial soup  of chemicals  about 3.6 billion years ago.  Specific chemicals combined to form amino acids – the basic building blocks of life. The amino acids combined to form proteins and the proteins combined to form the first  single celled living organism. And these cells developed to form the multicellular plants and animals that we know today.

The Primordial Soup

  The first single celled organism is also known as the LUCA or the Last Universal  Common Ancestor. It  resembled a modern day cell with its own nucleic acid, lipids, and genes capable of reproduction. It also had the complete blueprints for DNA replication, RNA transcription and protein synthesis.

There is widespread scientific consensus on how  the LUCA  developed into the multicellular complex life forms we see on earth today. But for a long time, it was not known how or what caused the amino acid blocks in the primordial soup to combine to form the LUCA.

A common theory to explain this phenomenon is the ‘RNA world’ theory. Ribonucleic acid (RNA) is a polymeric molecule implicated in coding, decoding, regulation, and expression of genes. Together with DNA and proteins, it is one of the main macromolecules  essential for all forms of life.

 The RNA world theory suggests that RNA lifted itself from the primordial soup of chemicals to form short peptides which then formed the fist cell. But recent research by two long-time University of North Carolina scientists — Richard Wolfenden, PhD, and Charles Carter, PhD  suggests that RNA did not work alone – that RNA and amino acids developed simultaneously.
“Our work shows that the close linkage between the physical properties of amino acids, the genetic code, and protein folding was likely essential from the beginning, long before large, sophisticated molecules arrived on the scene,” Carter said in a statement. “This close interaction was likely the key factor in the evolution from building blocks to organisms.”

Protein must fold in specific way to function properly.  The complex process of protein folding depends on  both the polarities of the  amino acids (how they distribute between water and oil) and their sizes.  It is during the process of protein folding that the amino acids arrange themselves into 3-dimensional structures capable of a particular biological function.

Protein folding  is brought about by the tRNA – a type of RNA known as the transcriptor RNA. One end of the tRNA selected the amino acids by size while the other end selected the  amino acids by polarity. This helped to transfer the genetic code  accurately to the messenger RNA which could then make the correct amino acid.

“Dr. Wolfenden established physical properties of the 20 amino acids, and we have found a link between those properties and the genetic code,” Carter said. “That link suggests to us that there was a second, earlier code that made possible the peptide-RNA interactions necessary to launch a selection process that we can envision creating the first life on Earth.”

“The collaboration between RNA and peptides was likely necessary for the spontaneous emergence of complexity,” Carter added. “In our view, it was a peptide-RNA world, not an RNA-only world.”

The National Institutes of Health funded this work. Dr. Wolfenden holds a joint appointment in the department of chemistry in the College of Arts and Sciences at UNC-Chapel Hill.

Monday, 12 January 2015

Almonds can Reduce Belly Fat

Can eating a handful of almonds daily reduce belly fat?

A study  carried out in the Pennsylvania State University and published in the  Journal of  the American Heart Association suggests that including 42 gms (1.5 ounces) of almonds daily can not only cut down on the risk of heart diseases but also reduce belly fat,  producing a trimmer waistline.

In a 12 week randomized, controlled clinical study, the scientists compared 52 overweight, middle aged adults who had high cholesterol but were otherwise healthy. All the paticipants were put on an identical  cholesterol lowering diet, with all meals and snacks in amounts necessary to maintain their body weight.

But while  half of the  group was given a snack of 42 gms of almonds daily, the other group was allowed to snack on a banana muffin. This was the only difference in the diet. The almonds and the banana muffin contained the same amount of calories.  There is 160 calories in an ounce of almonds as well as protein, fibre, vitamin and minerals. A single almond weighs approximately 2 gms.

After six weeks, it was noted that the  participants on the diet with almond snacks had  significantly reduced  central adiposity with resultant decrease in waist circumference and belly fat.Leg fat was also considerably reduced. There was no difference in total weight between the two groups. Central adiposity is  a well known risk factor for heart disease.

Not only that, there was reduction in the total cholesterol,   LDL cholesterol and remnant lipoproteins.

Belly fat not only makes the body unsightly, but it  is also linked to metabolic syndrome - a disorder characterized by a combination of diabetes, high blood pressure, high cholesterol levels and central obesity. The nuts moderate blood sugar level - particularly beneficial for people with diabetes.

Almonds are also high in monounsaturated fatty acids and vitamin E which protect against Alzheimer's disease, The flavonoids in the almond skin act as anti-oxidants and  together with Vitamin  E decreases wrinkles and age spots.

"Our research found that substituting almonds for a high-carbohydrate snack improved numerous heart health risk factors, including the new finding that eating almonds reduced belly fat," said Claire Berryman, lead researcher of the study. 

"Choosing almonds as a snack may be a simple way to help fight the onset of metabolic and cardiovascular diseases," said Berryman. 

The study provides evidence that snacking on almonds instead of a high carbohydrate snack helps to limit belly fat and has overall benefits on body composition.

Monday, 17 March 2014

The Playing Fields of Science: Searching for a New Earth

The Playing Fields of Science: Searching for a New Earth: Is there anybody else out there? Or are we the only living things in the universe? Humans have  asked themselves this question for as long ...

Thursday, 27 February 2014

Human Lungs made from Stem Cells for the First Time

In a remarkable scientific breakthrough, scientists at the University of Texas Medical Branch has created a human lung in the laboratory. Research into the process of developing new lungs started in July 2010.

In experiments on rats, the scientists stripped down rat lungs from all cells by a process of freezing and thawing and exposure to detergent. This caused only the scaffolding of the lungs, composed of structural protein like collagen and elastin tissue, to remain. This acellular scaffold was then seeded with  mouse embryonic stem cells. The cells thrived on this scaffold and developed into new lungs .

The lung is one of the most complex organs in the body - the   cells in the respiratory tree ( trachea and bronchii) is different from the cells in the alveoli (small air sacs). These different cells were successfully grown in the experiment.

On 14th February  this year, the scientists  could repeat the process in human lungs. Lungs were taken from two children who had died from a trauma. The lungs were too damaged to be used for transplants but still had some healthy tissue.

One of the lungs was used as the scaffold by stripping away all cells. Cells from the other lung was was then seeded onto the scaffold. The structure was then immersed in a  media containing nutrients and stimulating factors (placed in a fish tank bought from a pet store!). And in about 4 weeks, the human lung emerged.

The picture on the left is of the scaffold  of collagen tissue. Image B is of the lungs after they have  formed - they look pinkish and dense because of the   new cells.

The scientists have managed to repeat the process successfully in another two children who had died.

Lungs developed from stem cells will probably become available for transplants into humans after about 12 years. They will be first transplanted into pigs to see how well they perform in the body.

This is an exciting step forward in regenerative medicine. For people who suffer from  serious respiratory conditions like COPD and Cystic Fibrosis, lung transplants often provide the only hope for long term survival. Many persons die of the disease before a matching donor can be found. The successful engineering of human lungs in the lab for the first time provides a definite ray of hope  for humans.

Tuesday, 25 February 2014

Indian team among finalists for Google lunar X prize

Team Indus , founded by Rahul Narayan and Indranil Chakravarty has been named among the five finalists aiming for a milestone prize  in the Google Lunar X Prize. The milestone prizes are meant to help fund some of the competitions best ideas.

 The Google Lunar X Prize  was announced in September 2007.  The total prize at stake was 30 million in incentive based prizes with a deadline of December 2015. There were 33 teams in the competition when registrations closed in 2011.  Currently, 18 remain in the competition.

The aim was something never accomplished at any time - the safe landing of a private craft on the surface of the moon.  The private company which wins the prize will not only have to land the spacecraft safely on the moon surface but also travel 500 meters above, below or on the surface of the moon and also send back at least two 'Mooncasts' to the earth. Bonus prizes could be picked up for exploring lunar artifacts or surviving the lunar night. Milestone prizes for reaching certain milestones were also declared.

The teams have to:
 (a) develop a spacecraft that can do a soft and safe landing on the moon,
 (b) develop a rover that can dismount from the landing craft and travel at least 500 meters on the moon
(c) develop an imaging system that can send back high quality images and videas from the surface of the moon.

On 19th February, the organisers announced the Milestone prizes in these three categories. Team Indus is among  three finalists for the landing system and among the four named for the imaging system.

The other teams among the finalists are Astrobotic and Moon Express from the USA, Hakuto from Japan and Part Time Scientists from Germany.

Chakraborty and Narayan, friends since Standard 6 in school,  resigned from their jobs and decided to focus on this space venture but had barely any funds to do so. They  managed to borrow the $50,000 required for the registration  from friends and family. They also manage to stimulate enough interest to garner support from a large number of people, especially from the social media.

But it is not going to be easy -  they need a further $34 million to build and launch the spacecraft. Since this is a competition for a private  space craft, they cannot take government help.

Nevertheless, doors do open up and here is hoping that Team Indus succeeds in winning the prize. That will be a great day for India and all Indians.