sábado, 14 de junio de 2014

FISIOLOGIA DE HEMOSTASIA (COAGULACION)

Video de Bayer sobre coagulación

video

La marihuana puede resultar beneficiosa en el tratamiento de las enfermedades autoinmunitarias

La marihuana se usa actualmente para fines médicos, entre otros, para aliviar los efectos secundarios de la quimioterapia y tratar el dolor crónico. El "Journal of Biological Chemistry" informó de que científicos estadounidenses han encontrado ahora una posible aplicación nueva: el tratamiento de las enfermedades autoinmunitarias.
Científicos de la Universidad de Carolina del Sur (Columbia) investigaron si el tetrahidrocannabinol (THC) presente en la marihuana es capaz o no de alterar la expresión del ADN a través de vías epigenéticas. Al hacerlo, descubrieron que el THC afecta en realidad a un grupo de moléculas denominadas histonas. El sistema inmunitario, por tanto, queda suprimido.
Normalmente, la supresión del beneficioso sistema inmunitario es una de las consecuencias negativas del uso de la marihuana. Pero en las enfermedades autoinmunitarias, como la artritis, el lupus o la esclerosis múltiple, en las que la inflamación crónica desempeña un papel fundamental, el uso de la marihuana podría ser efectivo, sugieren los investigadores
Tomado de Univadis.com

  • Xiaoming Yang
  • Venkatesh L. Hegde
  • Roshni Rao
  • Jiajia Zhang,
  • Prakash S. Nagarkatti
  • and Mitzi Nagarkatti 
Histone modifications are associated with Delta(9)-tetrahydrocannabinol-mediated alterations in antigen-specific T cell responses. J. Biol. Chem. jbc.M113.545210. First Published on May 19, 2014,doi:10.1074/jbc.M113.545210

Cannabis can disrupt fertility in men

Men who take cannabis regularly could impair their ability to father a child. According to a British study published in "Human Reproduction", cannabis changes the shape and size of sperm.
For the study, scientists from the universities of Sheffield and Manchester recruited over 2,200 men from 14 fertility clinics in Great Britain and asked them to complete detailed questionnaires about their lifestyle and medical history. Data on sperm morphology was available from 1,970 men. In 318 of them, less than four per cent of the sperm was of normal size and shape. These men were compared to the other 1,652 people.
The researchers found that men with less than four per cent of "normal" sperm, were nearly twice as likely to have produced the sperm samples during the summer months (June to August), or, if they were younger than 30 years of age, they had used cannabis during the previous three months. However, the morphology of the sperm was better when the subjects had been sexually inactive for more than six days.
Other lifestyle factors such as smoking or drinking did not affect shape and size of the sperm. However, effects on the DNA of the sperm could not be entirely ruled out.
Men with poor sperm morphology were frequently looking for possible factors in their lifestyles that could be causing this, said study author Allan Pacey. "It is therefore reassuring to find that there are very few identifiable risks." He advised cannabis users to stop using the drug if they want to father a child.
Tomado: Univadis.com
Ref:  A: Pacey y cols.  Modifiable and non-modifiable risk factors for poor sperm morphology. Hum. Reprod.

martes, 27 de mayo de 2014

El Futuro de la Medicina Genómica



Conferencia de Andrew Hessel  quien habla del futuro de la medicina genómica
Gracias a la recomendación del Q. Ignacio Navarro
Tomado de aldeadigitalmx.com

lunes, 26 de mayo de 2014

ALTERACIONES DE LA COAGULACION EN HEPATOPATIAS



Chromium supplementation cannot prevent diabetes

Around one quarter of the US population suffers from impaired fasting glucose, a preliminary stage of type 2 diabetes. Earlier studies have indicated that chromium supplements may have a positive effect and prevent the onset of diabetes. However, a study published in "Biological Trace Element Research" now suggests that this may not be the case.
In a meta-analysis, a researcher at the University of Miami analysed studies from the past 30 years on this topic using an improved statistical method. 16 studies published from 1985 to 2012 in which participants aged 36 to 67 years received different doses of chromium were analysed. The supplements included chromium chloride, chromium picolinate, chromium nicotinate, chromium dinicocysteinate and chromium yeast.
The analysis showed that administering chromium did not reduce the fasting glucose levels in diabetics or non-diabetics. "Some previous research reported that chromium supplements lower the levels of fasting glucose," said study author Christopher Bailey. "However, the effect may have been exaggerated or mistaken for the effects of other concurrent treatments, such as exercise training." The researcher also emphasised that previous studies had used other statistical methods that may have led to differing results.
"Although chromium supplementation doesn't lower fasting blood sugar, there may be other beneficial effects on the body that require more research," says Bailey. "Fasting blood sugar is only one aspect of human health.
Tomado de Univadis.com
Biological Trace Element Research

miércoles, 14 de mayo de 2014

Recycling a Patient's Lost Blood During Surgery Better Than Using Banked Blood

     Patients whose own red blood cells are recycled and given back to them during heart surgery have healthier blood cells better able to carry oxygen where it is most needed compared to those who get transfusions of blood stored in a blood bank, according to results of a small study at Johns Hopkins.
      In a report for the June issue of the journal Anesthesia & Analgesia, the researchers say they found that the more units of banked blood a patient received, the more red cell damage they observed. The damage renders the cells less flexible and less able to squeeze through a body’s smallest capillaries and deliver oxygen to tissues. Among patients who received five or more units of red blood cells from a hospital blood bank during the study, the damage persisted for at least three days after surgery. In the past, studies have linked transfusions to increased risk of hospital-acquired infections, longer hospital stays and increased risk of death.
     “We now have more evidence that fresh blood cells are of a higher quality than what comes from a blood bank,” says study leader Steven Frank, M.D., an associate professor of anesthesiology and critical care medicine at the Johns HopkinsUniversity School of Medicine. “If banked blood, which is stored for up to six weeks, is now shown to be of a lower quality, it makes more sense to use recycled blood that has only been outside the body for one or two hours. It’s always been the case that patients feel better about getting their own blood, and recycling is also more cost effective.”
      To recycle the blood, a machine known as a cell saver is used to collect what a patient loses during surgery, rinse away unneeded fat and tissue, and then centrifuge and separate the red cells, which are then returned to the patient should he or she need it. Disposable parts of the cell saver, which can be used to process multiple units of blood, cost around $120, compared to $240 for each unit of banked blood.
      Such recycling first became popular during the early years of the HIV/AIDS crisis, so patients could avoid the risk of getting the virus in transfused blood. Today, Frank says, the blood supply is much safer, with the incidence of contracting HIV from a transfusion down from one in 100 in the early 1980s to one in 2 million now — but focus should be on recycling, because fresher blood is better. The practice also reduces the risk of contracting hepatitis B or C infections, or of bad transfusion-related reactions, Frank adds.
     For the study, the Johns Hopkins researchers categorized 32 cardiac surgery patients by their transfusion status: those who received only their own recycled red blood cells (12 patients), those who received their own blood plus fewer than five units of banked blood (10) and those who received their own blood plus five or more units of stored blood (10). All had blood samples drawn before, during and for three days after surgery. The samples were examined for blood cell membrane stiffness and flexibility, a measure of how well oxygen is likely to get to where it is needed.
     In patients who received only their own recycled blood, their cells behaved normally right away, as if they had never been outside the body. The more blood a patient got from the bank, the less flexible their entire population of red blood cells. Three days after surgery, the red blood cells in the group that got the largest number of transfused units still had not recovered their full function.
     “If something is bad for you, a little bit might be OK, but a lot of it is much worse,” Frank says. “It turns out that blood is more like milk, which has a relatively short shelf life, than a fine wine, which gets better with age.”
     Frank cautions that cell saver machines are not appropriate for all operations, and not all hospitals have access to round-the-clock perfusionists to run them. For heart surgeries, however, a perfusionist is already in the operating room to run the heart-lung bypass machine. And, he adds, many operations are considered to be low risk for blood loss, in which case the cell saver is unnecessary. But he advocates wider use of recycled blood.
     “In any patient where you expect to give one unit of red blood cells or more, it’s cost-effective and beneficial to recycle,” he says.
     Patients who lose blood may also need platelets and plasma, which they receive regardless of whether they receive their own blood or blood from a bank.
Frank is medical director of the Johns Hopkins Center for Bloodless Medicine and Surgery, which primarily serves Jehovah’s Witnesses, who do not accept blood transfusions but will accept recycled cell saver blood. By using the cell saver as a primary method of blood conservation, their efforts have allowed these patients to do just as well or better than patients who get transfusions of donated blood, he says. Preliminary findings suggest patients who avoid banked blood develop fewer hospital-acquired infections.

Tomado de :hopkinsmedicine.org
Release Date: May 8, 2014