Revolution in Ophthalmology : Discovery of New Corneal Layer

Harminder Dua, a professor at the University of Nottingham has conducted a research to find out the number of layers in human cornea. Up to now it was believed that human cornea was made of only five layers, but with the findings of the Professor Harminder Dua, the anatomical description of the cornea has changed. 

The professor and his team have used cornea that were donated for research purposes. Then they have injected air into these cornea to separate and visualize the layers easily. They have scanned each and every layer through an electron microscope. Through this technique they were able to find a new layer. They have named the new layer as 'Dua's Layer'.

They have also stated that the reason for corneal hydrops is tear of Dua's layer. They have also pointed out the association of this layer with many other diseases of the cornea. Therefore, the discovery of this layer will take the field of ophthalmology in to a whole new level.  

Can Adults Form New Brain Cells?

Some human organs have the ability to grow until death (e.g: hair, skin), but some stop growing at very young age (e.g: neurons) . It is believed that the development of the brain is completed at very young age. Scientists believed that after that certain age, the human brain does not grow. But, according to the latest research findings, human brain cells grow even at adult age.

Kirsty Spalding, a molecular biologist at the Karolinska Institute in Stockholm, Frisén, and colleagues have done a research to find out the ability of brain cells to divide even at adult age. For this research they have used brains of deceased humans who were exposed to above-ground nuclear weapon testing 50 years ago. During these nuclear weapon testing Carbon 14 were released in to the atmosphere. These Carbon 14 were incorporated in to DNA of cells of people who were exposed. They have found out a way to test the amount of Carbon 14 with in DNA of these cells. In their study they have extracted hippocampi of 55 deceased people who had given their consent to use their brains for research purposes. They have found out that every day about 1400 cells in hypoccampal region are being replaced. 

According to this research, it is confirmed that the brain cells have the ability to regenerate even in adult age. The results of this research will help the development of many aspects of science, especially the field of medicine.

How studying squirrel hibernation helps in transporting organs

Squirrel hibernation is one of the most amazing wonders of the Mother Nature. There is a certain kind of squirrels (ground squirrels) who can undergo hibernation. In the state of hibernation the body temperature is brought down to an extremely lower level. These squirrels undergo this physiological state to survive during extremely cold whether.

These squirrels undergo hibernation in the time of the year where the environmental temperature falls, even down to 0 Celsius. In mammals, the body temperature is kept in a constant level. The body requires optimum conditions to function correctly. Most of the mammals are programmed to keep the optimum temperature by thermoregulations. When the body temperature goes down, the body burns energy from the fat reserves and generates heat. But, this is not possible for these squirrels due to lack of food. During the cold whether, the squirrels are unable to find food. Therefore, they have to survive with whatever the energy they have already stored within their bodies.

The animal body is composed of cells. The survival of the animal depends on the survival of the each and every cell in the body. The integrity of the cell depends on the intracellular and extracellular electrolyte concentrations. These concentrations are kept at their optimum concentrations by the pumps that are present in the cell membrane. These pumps need energy and optimum temperatures to work. These pumps in the ground squirrels differ from those of non-hibernating mammals. Their pumps are able to work at very low temperatures. Therefore, these pumps are able to keep the cells viable even under very low temperatures.

HOW DOES IT HELP IN ORGAN TRANSPORT?

The organs are transported in cold temperatures to keep then viable for a longer period. But at lower temperatures, the pumps may not work properly. The absence of functioning pumps in the cells makes the organs non-viable. But, if the scientists can find the exact kind of electrolyte pumps that work at very low temperatures, then the nature of these pumps can be used to find a way to store organs for a loner period of time so they can be transported to the required area.  

According to Cryo Letters, 2000, pubmed, organs taken from squirrels that were in deep hibernation survived in cold for up to 72 hours. But, the organs from non-hibernating squirrels were able to survive only for24 hours.

If these studies become successful, a way can be found to preserve organs for a longer period of time.

Long Standing Dialysis and Arterial Calcification

It is a common finding that patients with a history of long standing dialysis developing arterial calcification.  This is more frequently seen in patients with following associated risk factors.

1.      Diabetes

2.      Dyslipidemia

3.      Increased pulse pressure – pulse pressure is the difference between the systolic and diastolic blood pressures.

4.      disordered mineral metabolism

5.      Older patients

Investigation Findings:

·         Plain radiograph of the abdomen - marked calcification of the wall of the abdominal aorta and the common iliac arteries.

·         computed tomography of the lower abdomen -  calcification of the abdominal aorta

What is an “amalgam tattoo”?

Biopsy Appearance: interstitial accumulation of brown and black particles within the submucosa

Amalgam dental fillings are used in tooth restoration. Amalgam tattoo is caused by implantation of contents of amalgam dental filling in to adjacent mucosa.  Amalgam dental filling contain following ingredients.

1.      Mercury

2.      Silver

3.      other metals

Appearance: black, blue, or gray macules

They are asymptomatic but may mimic other dangerous lesions such as melanoma or Kaposi's sarcoma. Therefore, a biopsy can be done if the patient is worried or the practitioner is not sure to confirm. But, if the practitioner is experienced and sure about the diagnosis it is not necessary to do a biopsy.

Tuberculosis in the United States

Majority (>80%) of Tuberculosis cases in United States are due to reactivation of latent tuberculosis. Latent tuberculosis is a stage of tuberculosis infection where the there is not symptom indicating the disease, but the patients act as reservoirs of tuberculosis bacteria, Mycobacterium tuberculosis. But, if these latent cases of tuberculosis are detected early, they can be cured completely only by following a course of drugs. Therefore, in United Stated it is recommended to screen for latent tuberculosis cases.

Screening is recommended only for population subgroups with a high prevalence of latent tuberculosis infection or those with a high likelihood of progression from latent tuberculosis infection to active disease.

Direct detection of the bacteria in latent patients is very difficult because the number of bacteria is very low. Therefore, the commonly used method is the “Tuberculin Test”, which looks for the immune reaction which occurs only in infected persons. This test has a high sensitivity, but its specificity is very low.

Screening for latent tuberculosis using tuberculin test has been done in year 1999 and 2000. The test has revealed that 4.5% of people who underwent the test had tuberculosis. Of these positive patients only 5% has developed tuberculosis later in their life. Considering the above difficulties, two other tests methods have come into play. They are,

1.      QuantiFERON–TB Gold (QFT) (Cellestis)

2.      T-SPOT.TB test (Oxford Immunotec)

The disease is possible to cure completely only if the patients takes the course of antibiotics continuously for 9 months. Since this is a very long period, the patient compliance is as low as 50%.

How to prevention of Methicillin-resistant Staphylococcus aureus (MRSA) infections

MRSA is associated with,

1.      Ventilator-associated pneumonia – Pneumonia can be life threatening especially when it occurs in intensive care patients. These patients’ immune system is already compromised and infection with resistant bacteria multiplies the risks.

2.      Bloodstream infection associated with central venous catheters, and surgical-site infections – Hospitalized patients undergo various invasive procedures that involve access to the blood stream. This leads to introduction of resistant bacteria to the systemic circulation. 

These have become major problems in health sector because they are associated with significant amount of morbidity and mortality. These infections are acquired from the hospital a, because the resistant bacteria present in the hospital. A system called “MRSA BUNDLE” is used to prevent MRSA associated infections in the health care facilities.

This bundle consists of following guidelines.

1.      universal nasal surveillance for MRSA colonization

2.      contact precautions for patients who were carriers of MRSA

3.      hand hygiene

4.      institutional culture change whereby infection control became the responsibility of everyone who had contact with patients

Studies done show that MRSA infection rates have been reduced significantly when above guidelines are followed.