15.10.2009

Гипервитаминоз А

В детстве у меня был гипервитаминоз А - мама решила помочь мне справиться с трещинками на губах и помазала их витамином А из капсулки... Видимо - передоз. Потому что потом ещё неделю я ходила с распухшим, в красных пятнышках, личиком...
Вот и свежая статейка об эффектах витамина А при превышении дозы, читаю тут - http://www.biologynews.net/archives/2009/10/08/too_much_of_a_good_thing_scientists_explain_cellular_effects_of_vitamin_a_overdose_and_deficiency.html:

If a little vitamin A is good, more must be better, right? Wrong! New research published online in the FASEB Journal (http://www.fasebj.org) shows that vitamin A plays a crucial role in energy production within cells, explaining why too much or too little has a complex negative effect on our bodies. This is particularly important as combinations of foods, drinks, creams, and nutritional supplements containing added vitamin A make an overdose more possible than ever before.

"Our work illuminates the value and potential harm of vitamin A use in cosmetic creams and nutritional supplements," said Ulrich Hammerling, co-author of the study, from the Sloan-Kettering Institute for Cancer Research in New York. "Although vitamin A deficiency is not very common in our society, over-use of this vitamin could cause significant disregulation of energy production impacting cell growth and cell death."

Although the importance of vitamin A to human nutrition and fetal development is well-known, it has been unclear why vitamin A deficiencies and overdoses cause such widespread and profound harm to our organs, until now. The discovery by Hammerling and colleagues explains why these effects occur, while also providing insight into vitamin A's anti-cancer effects. The scientists used cultures from both human and mice cells containing specific genetic modifications of the chemical pathways involved in mitochondrial energy production. The cells were then grown with and without vitamin A, and scientists examined the impact on the various steps of energy production. Results showed that retinol, the key component of vitamin A, is essential for the metabolic fitness of mitochondria and acts as a nutritional sensor for the creation of energy in cells. When there is too much or too little vitamin A, mitochondria do not function properly, wreaking havoc on our organs.

"Beauty might be only skin deep, but vitamin A isn't. It goes to the nucleus of our cells and can affect our health for better or worse," said Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal. "Using too many products enriched with vitamin A could lead to negative, even fatal, consequences."

Source : Federation of American Societies for Experimental Biology

Безумие и гениальность

Читаем на http://www.eurekalert.org/pub_releases/2009-09/afps-mgs092809.php

Vincent van Gogh cut off his ear. Sylvia Plath stuck her head in the oven. History teems with examples of great artists acting in very peculiar ways. Were these artists simply mad or brilliant? According to new research reported in Psychological Science, a journal of the Association for Psychological Science, maybe both.

In order to examine the link between psychosis and creativity, psychiatrist Szabolcs Kéri of Semmelweis University in Hungary focused his research on neuregulin 1, a gene that normally plays a role in a variety of brain processes, including development and strengthening communication between neurons. However, a variant of this gene (or genotype) is associated with a greater risk of developing mental disorders, such as schizophrenia and bipolar disorder.

In this study, the researchers recruited volunteers who considered themselves to be very creative and accomplished. They underwent a battery of tests, including assessments for intelligence and creativity. To measure creativity, the volunteers were asked to respond to a series of unusual questions (for example, "Just suppose clouds had strings attached to them which hang down to earth. What would happen?") and were scored based on the originality and flexibility of their answers. They also completed a questionnaire regarding their lifetime creative achievements before the researchers took blood samples.

The results show a clear link between neuregulin 1 and creativity: Volunteers with the specific variant of this gene were more likely to have higher scores on the creativity assessment and also greater lifetime creative achievements than volunteers with a different form of the gene. Kéri notes that this is the first study to show that a genetic variant associated with psychosis may have some beneficial functions. He observes that "molecular factors that are loosely associated with severe mental disorders but are present in many healthy people may have an advantage enabling us to think more creatively." In addition, these findings suggest that certain genetic variations, even though associated with adverse health problems, may survive evolutionary selection and remain in a population's gene pool if they also have beneficial effects.

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For more information about this study, please contact: Szabolcs Kéri (szkeri@phys.szote.u-szeged.hu)

Psychological Science is ranked among the top 10 general psychology journals for impact by the Institute for Scientific Information. For a copy of the article "Genes for Psychosis and Creativity" and access to other Psychological Science research findings, please contact Barbara Isanski at 202-293-9300 or bisanski@psychologicalscience.org

Активные формы Кислорода в сигнальных каскадах!

Немного новостей об АФК в новом функциональном свете на http://www.eurekalert.org/pub_releases/2009-09/uoc--roi092309.php

For years, health conscious people have been taking antioxidants to reduce the levels of reactive oxygen in their blood and prevent the DNA damage done by free radicals, which are the result of oxidative stress. But could excessive use of antioxidants deplete our immune systems?

Research at UCLA's Jonsson Comprehensive Cancer Center has raised that question.

It has been known for decades that reactive oxygen species (ROS) - ions or very small molecules that include free radicals - damage cells. But much to their surprise, Jonsson Cancer Center researchers found that in Drosophila, the common fruit fly, moderately elevated levels of ROS are a good thing.

These small molecules act as an internal communicator, signaling certain blood precursor cells, or blood stem cells, to differentiate into immune-bolstering cells in reaction to a threat. After the progenitor cells differentiate, the ROS levels return to normal, ensuring the safety and survival of the mature blood cells, said Utpal Banerjee, a Jonsson Cancer Center researcher and senior author of the study.

The study is published in the Sept. 24, 2009 issue of the peer-reviewed journal Nature.

The new finding was launched when Banerjee and his team set out to discover why fruit flies had naturally occurring, slightly elevated levels of ROS in their blood cell precursors, which is atypical of most other precursor cells.

"Reducing levels of reactive oxygen is usually the goal, and what we found was surprising," said Banerjee, professor and chairman of the molecular, cell, and developmental biology department at UCLA. "Most stem cells don't want to be damaged, so they have very low ROS levels. We wanted to know why this was different in the cells that we were investigating."

Banerjee discovered that when ROS was taken away in the blood stem cells, they failed to differentiate into the immune-bolstering cells, called macrophages. On the other hand, when levels of ROS were further increased by genetic means, the blood stem cells "differentiated like gang busters," Banerjee said, making a large number of macrophages.

But how did this happen? The ROS, Banerjee said, acted as a signaling mechanism that kept the blood stem cells in a certain state – when levels rose, it was a message to the cell to differentiate.

The implications from the finding are several fold, Banerjee said. The blood stem cells are stress sensing cells, their function is to sense conditions that increase oxidative stress and react with an immune response. Keeping their ROS levels slightly elevated puts the cells on alert, sensitized and ready to respond to any threat quickly.

That sparked a question: If fruit fly blood stem cells and mammalian blood stem cells operate in the same way, is it a good thing for people to be taking antioxidants? Are antioxidants dulling the immune system and its ability to react to threats?

"On the one hand, it's good to have antioxidants to reduce the amount of reactive oxygen in our body that causes DNA damage," Banerjee said. "But if we find that those blood stem cells aren't primed to respond because the ROS levels are reduced, that would not be a good thing. Our findings raise the possibility that wanton overdose of antioxidant products may in fact inhibit formation of cells participating in innate immune response."

It is known that certain types of mammalian blood stem cells, called common myeloid progenitors, do have elevated levels of ROS, but it isn't known whether those levels operate as messengers for differentiation. Studies of mammalian systems are needed to determine why ROS levels are elevated and what, if any, function that serves in the cell. It is interesting, however, that these types of blood progenitors in mammals also give rise to macrophages, Banerjee said.

"What we found is that the fruit fly keeps its own ROS levels in the blood stem cells slightly high for its own benefit," Banerjee said. "We do not have any direct evidence that this is true in humans, but our results suggest that further studies are needed to investigate a possible signaling role for ROS in the differentiation of precursor cells in mammalian myeloid cell development and oxidative stress response."

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UCLA's Jonsson Comprehensive Cancer Center has more than 240 researchers and clinicians engaged in disease research, prevention, detection, control, treatment and education. One of the nation's largest comprehensive cancer centers, the Jonsson center is dedicated to promoting research and translating basic science into leading-edge clinical studies. In July 2009, the Jonsson Cancer Center was named among the top 12 cancer centers nationwide by U.S. News & World Report, a ranking it has held for 10 consecutive years. For more information on the Jonsson Cancer Center, visit our website at http://www.cancer.ucla.edu.

Новое лекарство от шизофрении

Интересно, как обычно на этом блоге! Статья с http://scienceblogs.com/corpuscallosum/2009/09/iloperidone_approved_for_treat.php?utm_source=combinedfeed&utm_medium=rss
The new drug is called iloperidone; the brand name in the USA will be Fanapt. It is yet another antipsychotic that blocks D2 and 5HT2 receptors. Although there is no universally accepted way of classifying drugs into families, it will be referred to as an atypical or second-generation antipsychotic. This designation will indicate a loose kind of similarity to risperidone, aripiperazole, ziprasidone, quetiapine, olanzapine, clozapine, and paliperidone.

It turns out that there is a Wikipedia page for iloperidone. It is not one of the better pages on Wikipedia.

Iloperidone is a monoamine directed towards acting upon and antagonizing specific neurotransmitters.

Iloperidone does act upon the transmitter. It blocks the receptor, which causes the transmitter to be ineffective, or less effective, at transmitting whatever message it otherwise would have transmitted.

There are several other quibbles I have with the Wikipedia page. If I were unemployed, I would edit it. But it is going to take a lot of work.

Anyway, I could write the kind of blog post that I usually have written when potentially-interesting new drugs come out. But it turns out that there is already a good, concise article in an open-access journal. It says all the things I would have said.

Iloperidone for schizophrenia
Peter J. Weiden, MD, and Jeffrey R. Bishop, PharmD, BCPP
Current Psychiatry Online
Vol. 8, No. 9 / September 2009

Iloperidone is a second-generation (atypical) antipsychotic the FDA approved in May 2009 for treating acute schizophrenia in adults (Table 1). Iloperidone is not a derivative (metabolite, isomer, or different formulation) of any other antipsychotic. Clinical trials have shown that iloperidone is efficacious and suggest that for some patients its side-effect profile may be more favorable than that of other antipsychotics.

It is expected to be available later this year. It is not possible for me, or anyone else, to say exactly when this will be.

The high points are: oral bioavailability 95%, half-life about 18 hours, protein binding about 95%, high affinity for D2 and 5HT2A, low for H1, minimal for muscarinic, and moderate for NEα1. The cost will be too high, but I don't know exactly how high. The manufacturer, Vanda Pharmaceuticals, reportedly is working on a long-acting injectable product.

The one sort of interesting thing has to do with the alpha-1 antagonism. This is a nuisance sometimes, because it can cause orthostatic hypotension (dizziness upon standing up, due to drop in blood pressure). This is a side effect, which may or may not happen in a given individual. It is potentially an adverse effect.

Prazosin is an antihypertensive drug that blocks alpha-1 receptors. Prazosin has been used, off-label, to reduce nightmares in persons with PTSD.

Could iloperidone have a similar effect? If so, it would be a side effect, but not an adverse effect. It would be a beneficial side effect. It remains to be seen whether this will turn out to be the case. In general, it is tricky to anticipate clinical effects, based upon the in vitro pharmacology of a drug, when it comes to the effects in the brain.

Несколько весёлостей из научных новостей о сексе

Здесь - о сексе и оргазме. Всегда ли одно не возможно без другого?
Здесь - о полезности здоровой сексуальной жизни для самочувствия женщин.

02.10.2009

Об эффективности обогащённой тромбоцитами плазмы

Ещё один объект моего изучения и тестирования попал сегодня в сводку новостей с научных фронтов. Прочитала на http://www.biologynews.net/archives/2009/10/01/plateletrich_plasma_does_it_work.html:

Platelet -rich plasma (PRP) is currently used as an alternative treatment method for several common orthopaedic-related sports medicine conditions. According to a new study in the October issue of the Journal of the American Academy of Orthopaedic Surgeons (JAAOS), early outcomes of PRP appear promising; however, larger clinical studies are still needed to determine the benefits of its use.

"Some believe that PRP may catalyze the body's repair mechanisms at areas of injury, improve healing and shorten recovery time," said study co-author Michael Hall, MD, a senior orthopaedic surgery resident at the NYU Hospital for Joint Diseases in New York. "However, there currently is minimal evidence of this clinically and more research must be performed."

A Simple Process and Procedure

  • Obtaining and utilizing PRP is a relatively simple process: a patient's own blood is placed into a centrifuge that rotates at high speed.
  • This procedure separates the red blood cells from the platelets, which are blood cells that release growth factors that help the body heal itself.
  • Next, the physician takes the platelet-rich portion of this blood (PRP) and injects it directly into the patient's injured area and the treatment is complete.

PRP Used Primarily for Chronic Conditions

PRP treatments have been used for the past two decades to improve wound healing and bone grafting procedures by plastic and maxillofacial (mouth, jaw and neck) surgeons. It is only in recent years that orthopaedic surgeons and sports medicine specialists have utilized this technology.

PRP use in sports medicine primarily has been for the treatment of chronic tendon conditions, but also for acute muscle injuries and for the augmentation of tendon repair in the operating room.

The most common applications include:

  • tennis elbow (lateral epicondylitis);
  • Achilles tendonitis (inflammation and swelling of the Achilles tendon);
  • patellar tendonitis (inflammation of the patellar tendon, also called "Jumper's Knee"); and
  • rotator cuff tendonopathy.

Should I Have PRP Treatment?

According to Dr. Hall, PRP use has increased in recent years, and it has become a popular topic of discussion because the process is "simple, quick and relatively safe for patients."

"Use of PRP has increased, in large part due to new devices that enable fast preparation in the outpatient setting. A patient gives a blood sample and 30 minutes later can receive their injection," he explained. "There is always a risk of infection with any injection, and some have reported increased pain or inflammation at the injection site, but otherwise the risks with PRP appear minimal."

Questions to Ask Your Doctor

Each patient and injury is unique; therefore it is important to discuss any treatment with an orthopaedic surgeon. If PRP treatment is recommended, Dr. Hall suggests asking your doctor the following to help determine if it is right for you:

  1. What is your experience in administering PRP? (Precise placement of PRP injection into the area of injury is important for it to be effective, therefore physicians with more experience may be best.)
  2. What are possible side effects? (Examples include increased pain or inflammation at the injection site.)
  3. How many injections will I receive? (Several studies have reported using multiple injections, but the benefit of this is unknown.)
  4. Will there be any restrictions? (Generally, patients are asked to avoid strenuous activity or sports for a short period of time after the injection to aid in the healing process.)
  5. Will my insurance cover treatment? (Currently, most insurance companies do not cover treatment.)

Also, before embarking on PRP, Dr. Hall suggests trying conventional treatments, such as anti-inflammatory medications, physical therapy, massage, activity modification, bracing and even cortisone injections.

"The bottom line is that there are some studies indicating that PRP may be beneficial in the healing process. Does it really have a positive effect clinically? We don't know," said Dr. Hall. "The good news is that there are a tremendous amount of studies underway. Hopefully, in the next few years, we will be able to help determine the true benefit of PRP."

Source : American Academy of Orthopaedic Surgeons