Tuesday, December 22, 2009
A vitamin jab that shrinks tumours in a day is being hailed as a powerful new treatment for cancer.
British researchers who are testing the therapy say injecting an extract of vitamin E into the bloodstream has a rapid effect.
Within 24 hours, tumours begin to shrivel and after ten days they have almost completely disappeared.
So far, research has focused on the vitamin's ability to find and destroy skin cancers.
But scientists from the University of Glasgow and the University of Strathclyde, who led the research, are confident it will work for other types of tumours, too.
Vitamin E is vital for helping the body to fight illness and is found in foods such as vegetable oils, cereals, nuts, green vegetables and eggs.
It is rich in antioxidants that protect against disease by blocking damage from free radicals - harmful molecules that attack cells in much the same way as rust rots a car
But for the past few years, one particular compound found in vitamin E has attracted attention as a potential medicine that can attack cancer once it has set in.
Tocotrienol is an extract of vitamin E found in abundance in palm oil, cocoa butter, barley and wheat germ.
In the mid-Nineties, scientists carrying out laboratory tests discovered the ability of tocotrienol to halt the growth of breast cancer cells.
Since then, there have been several studies to see if injecting the vitamin extract into the body can help women who have a tumour.
But most failed, for several reasons.
First, much of the extract ended up floating around the bloodstream, as there was no easy way of directing it towards the cancer.
Second, very high quantities of tocotrienol can be toxic to healthy tissue as well as cancerous ones. And there is the added concern that vitamin E supplements have in the past been linked to an increased risk of lung cancer.
The latest breakthrough gets round all of these by smuggling the vitamin extract past healthy cells and making sure it hits its only target - the tumour.
To do this, scientists encapsulated the vitamin extract inside thousands of microscopic bubbles made from fat.
This meant the tocotrienol could travel through the body without damaging healthy cells.
Then, to make sure the cargo-laden bubbles headed straight for the tumour, the researchers coated them with the protein transferrin.
'This new formulation proved to be efficient and has had extremely encouraging results'
This has the job of escorting iron through the bloodstream to where it is needed, so that it can be absorbed by cells.
Cancer cells need a rich supply of iron in order to keep reproducing. This means they have large numbers of receptors on their surface designed to attract transferrin and the iron it is carrying.
By disguising the tumour-busting vitamin inside a bubble, the scientists were able to sneak it inside the cancer cell, where it launched its attack.
'This new formulation proved to be efficient and has had extremely encouraging results,' says research leader Dr Christine Dufés.
A separate British trial, due to end in 2012, is looking at whether vitamin E can stop bladder cancer returning in patients who are in remission.
Cancer Research UK voiced concerns about vitamin E supplements' previous link with lung cancer and said the new treatment's safety would have to be thoroughly tested before it could be widely used.
'This research is at an early stage and more work is needed before we'll know if this could be a viable tool in the future,' says health information officer Dr Jodie Moffat.
'Previous studies have found high doses of vitamin supplements can actually increase the risk of certain types of cancer, which highlights just how important testing with people is.'
A bandage that gradually releases infection-fighting drugs and then dissolves once the wound has healed could help thousands of burns victims.
The high-tech dressing, pioneered at Tel Aviv University in Israel, is designed to combat the high rate of infections among burns patients.
It's estimated that as many as 70 per cent of patients with very severe burns die from infections that penetrate the body through damaged skin and wounds.
Standard care involves regular cleaning and changing of bandages, which can disrupt the healing process.
One of the major problems doctors face is that if these kinds of wounds are too dry, they won't heal fully; if they are too moist, there is a high risk of contamination by bacteria.
To get round this, Israeli scientists have developed special fibres that are woven in such a way that they can 'store' significant quantities of antibiotic drugs.
These fibres are used to make a dressing that sits on top of a burn and allows the medicine to seep slowly into the wound.
The fibres are also biodegradable, which means that after a few days they dissolve harmlessly, removing the need to change the bandage constantly and expose the wound.
Tests show the experimental dressing can wipe out dangerous bacteria within days.
'We've developed the first wound dressing that releases antibiotics and biodegrades in a controlled manner,' says Professor Meital Zilberman, who is a member of the research team.
Friday, December 11, 2009
 Influence of tourniquet application on venous blood sampling for serum chemistry, hematological parameters, leukocyte activation and erythrocyte mechanical properties
Background: Venous blood sampling is usually performed using a tourniquet to help locate and define peripheral veins to achieve successful and safe venipuncture. Despite widespread usage of tourniquets for venipuncture by medical and laboratory staff, very few are aware of the effects of tourniquet application on laboratory parameters. In addition, definitive guidelines regarding when and how to use a tourniquet for blood sampling are lacking. The aim of the present study was to define the optimal sampling time after tourniquet removal to avoid adverse impact on laboratory analytes.
Methods: Blood oxygen and carbon dioxide partial pressure, pH, oxyhemoglobin saturation (satO2), hematological parameters, serum electrolyte concentrations, erythrocyte, deformability and aggregation, leukocyte activation and nitrite/nitrate concentrations obtained 180 s after tourniquet release were compared with baseline values for 10 healthy subjects.
Results: Blood gases, hematological parameters and serum electrolyte levels were not affected by the application and removal of a tourniquet. However, there were significant decreases in erythrocyte deformability at 90, 120, 180 s, and increases in erythrocyte aggregation at 5 and 30 s following removal of the tourniquet. A significant increase in granulocyte respiratory burst at 60 s was observed, confirming leukocyte activation due to application of the tourniquet. There were no significant alterations of blood nitrite/nitrate levels.
Conclusions: Our blood sampling technique which mimicked the application and release of a tourniquet indicated unaltered values for routine blood gases, hematological testing and serum electrolyte levels. Conversely, hemorheological measurements can be affected. Therefore, it is strongly recommended that tourniquet application should be avoided during blood sampling or, if this is not possible, the procedure should be well standardized and details of the sampling method should be reported.
 Additives and order of draw
The tubes in which blood is transported back to the laboratory contain a variety of additives or none at all. It is important to know which the laboratory requires for which test. In general whole blood needs to be mixed with EDTA which chelates calcium to prevent it clotting, unless the clotting time is the test to be measured in which citrates is used. The majority of biochemistry tests are performed on serum and so either a plain tube or a clotting accelerator is used. This clotting accelerator can interfere with some assays and so a plain tube is recommended in these cases but will obviously delay the result. Some assays also want whole blood but the EDTA can interfere and in this case Lithium Heparin is an alternative.
With the vacuum tube system, the needle pierces the top of the sample tube and will potentially come into contact with the additives in the tube. As it is a hollow needle some of this can be carried into the next tube and contaminate it. The most likely additive to cause trouble is EDTA which will affect the coagulation time assays and by chelating some of the metal ions may interfere with some of the biochemistry results(especially potassium). Thus EDTA samples should be drawn last in most cases and plain tubes drawn first.