Day: 03/08/2011

Helicobacter pylori infection, host genetics and gastric cancer

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Helicobacter pylori infects half the world’s population and is responsible for a considerable global health burden, including peptic ulcer disease and gastric cancer. The infection causes a chronic gastritis, the severity and distribution of which determine the clinical outcome. Bacterial, environmental and host genetic factors combine to define the degree of gastric damage. Most patients have a limited mild pan-gastritis with no significant clinical consequences. Antral-predominant gastritis is associated with high gastric acid output and an increased risk of duodenal ulcers. Corpus-predominant gastritis is associated with a reduction in gastric acid, multifocal gastric atrophy and an increased risk of gastric cancer. Host genetic factors are particularly important in defining the severity and extent of Helicobacter-induced gastritis. The most relevant and consistent genetic factors uncovered thus far are in the interleukin-1 and tumor necrosis factor-A gene clusters. These cytokines appear to play a key role in the pathophysiology of gastric cancer and their roles have been confirmed in animal models that mimic human gastric neoplasia. More genetic factors have also been uncovered and, with advancing technology, there is every prospect of defining a full genetic risk profile in the next decade. This will aid in targeting the testing and treatment of Helicobacter pylori, which offers a true opportunity to prevent and defeat this global killer.Helicobacter pylori infects half the world’s population and is responsible for a considerable global health burden, including peptic ulcer disease and gastric cancer. The infection causes a chronic gastritis, the severity and distribution of which determine the clinical outcome. Bacterial, environmental and host genetic factors combine to define the degree of gastric damage. Most patients have a limited mild pan-gastritis with no significant clinical consequences. Antral-predominant gastritis is associated with high gastric acid output and an increased risk of duodenal ulcers. Corpus-predominant gastritis is associated with a reduction in gastric acid, multifocal gastric atrophy and an increased risk of gastric cancer. Host genetic factors are particularly important in defining the severity and extent of Helicobacter-induced gastritis. The most relevant and consistent genetic factors uncovered thus far are in the interleukin-1 and tumor necrosis factor-A gene clusters. These cytokines appear to play a key role in the pathophysiology of gastric cancer and their roles have been confirmed in animal models that mimic human gastric neoplasia. More genetic factors have also been uncovered and, with advancing technology, there is every prospect of defining a full genetic risk profile in the next decade. This will aid in targeting the testing and treatment of Helicobacter pylori, which offers a true opportunity to prevent and defeat this global killer.

source: journal of digestive disease

Flying robots could help in disaster rescue

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Swarming micro air vehiclesTen of these flying robots could set up a 1.5 kilometre communication line between rescuers 

Laboratory of Intelligent Systems, Swiss Federal Institute of Technology in Lausanne

Swarms of flying robots inspired by insect behaviour could be used to establish emergency rescue networks following natural disasters, say Swiss researchers who plan to start testing their system from April.

In the aftermath of earthquakes and other disasters, when communications infrastructure is damaged or overloaded, the first thing rescue teams do is set up temporary radio or mobile communication networks to coordinate the search for survivors.

But these networks have limited data transmission capacity, take time and specialists to establish, and can suffer interference from existing commercial networks.

Now a team of scientists at the Swiss Federal Institute of Technology in Lausanne, has developed a quick way to establish a wireless network using ‘swarming micro air vehicles’ — flying robots.

“The main point is to provide high bandwidth digital communication, for instance to transmit high-resolution images, video streams and voice,” Jean-Christophe Zufferey, the project leader, told SciDev.Net.

A fleet of vehicles would hover above a disaster zone with a module in the wing of each robot emitting a wireless signal to enable communication between rescuers.

Each vehicle is made from lightweight, flexible polypropylene plastic, weighs less than half a kilogram and has a wing span of 80 centimetres. A battery-powered motor enables each vehicle to fly for up to half an hour before visiting a recharging station.

The team is preparing a paper describing how it flew 10 robots — enough to establish and autonomously maintain a 1.5-kilometre communication line — to link up two rescuers on the ground.

To distribute the vehicles effectively above a designated zone, Zufferey’s team took inspiration from the way ants leave chemical trails to guide colonies to sources of food. Some of the vehicles hover in small circles linked to the location of rescuers and the other vehicles navigate around these markers.

Renzo De Nardi, a robotics researcher at University College London in the United Kingdom, is impressed by the ease with which the system can deliver a high quality wireless signal, a feature that would be particularly useful in developing countries lacking fixed communication networks.

De Nardi warned, however, that the lightweight vehicles would likely be affected by wind and bad weather.

Julian De Hoog, head of the Robotic Search and Rescue project at the UK-based University of Oxford, described the aerial robot swarm as an “impressive achievement”, but said the main challenge will be to boost vehicle durability while keeping them light enough to be safe if they crash.

He added that rescuers have many other factors competing for their attention so using the technology “would have to be very simple and straightforward”.

The researchers will begin testing the technology in mock rescue contexts this spring.

It will take up to three years to prove the robustness of the technology in real-life situations, according to Zufferey, although a simpler, single-robot system for crop and biodiversity monitoring has already been rolled out through a spin-off company, senseFly.

Meanwhile his team is also working to develop ground-based robots and flying vehicles that can enter buildings and scan for survivors.

source: scienceVX

url:
http://www.scidev.net/en/news/flying-robots-could-help-in-disaster-rescue.html

author:James Dacey

Facebook Boosts Self-esteem

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Facebook Allows You to Put Your Best Face Forward, Which Can Make You Feel Better About Yourself, Study Finds

 

college girl on laptop

March 4, 2011 — If you’re feeling a little blue, don’t look into a mirror. Take a gander instead at your Facebook page, which may boost your self-esteem.

That’s the conclusion of a new study by Cornell University researchers involving the wildly popular online social networking site.

The reasons for this positive effect seem clear, the researchers say.

  • Facebook lets you put your best face forward, allowing you to filter out anything that will make you feel bad.
  • Facebook can depict you in a very positive light, without blemishes a mirror might reflect, real or imagined.

“Unlike a mirror, which reminds us of who we really are and may have a negative effect on self-esteem if that image does match with our ideal, Facebook can show a positive version of ourselves,” Jeffrey Hancock, PhD, one of the authors of the study, says in a prepared statement. “We’re not saying that it’s a deceptive version of self, but it’s a positive one.”

Facebook and Self-esteem

Hancock and fellow researcher Amy L. Gonzales, MA, now a scholar at the University of Pennsylvania, signed up 63 Cornell students to take part in experiments in the university’s Social Media Lab.

The students were either seated at computers showing their Facebook profiles or at computers that were turned off. Some of those at turned-off computers had mirrors to look at, and others didn’t. Students in the third group were encouraged to fiddle with their Facebook profiles.

The students on Facebook were allowed to spend three minutes perusing the page, exploring only their own profiles and associated tabs.

All 63 students were given a questionnaire designed to measure self-esteem.

Students who looked at their Facebook profiles during the experiment had higher self-esteem than students in the groups where the computer was turned off.

Students who viewed their Facebook profile but left their profile site during the study reported lower self-esteem than students who exclusively viewed their own profile site.

Also, study participants who edited their Facebook profile during the study reported higher self-esteem than those who did not change their profile. The researchers viewed editing as a primary means of optimizing self-presentation. Because Facebook users can be selective about what they say or present about themselves, including photographs and autobiographical information, they can present  themselves as conforming to an ideal, the authors write.

Polishing Your Image

With Facebook, users are able to enhance “awareness of the optimal self,” the study says. And the self-image can be polished unabashedly with clever comments and by providing personal details and photos that users deem flattering.

“For many people, there’s an automatic assumption that the Internet is bad,” Hancock says. “This is one of the first studies to show that there’s a psychological benefit of Facebook.”

source: Cyberpsychology, Behavior and Social Networking.

Drug-Induced Hair Loss

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Medications are designed to treat a variety of health conditions, but sometimes they can have unwanted side effects — including changes to the hair. Certain drugs can contribute to excess hair growth, changes in hair color or texture, or hair loss.

Drug-induced hair loss, like any other type of hair loss, can have a real effect on your self-esteem. The good news is that in most cases, it’s easily reversible once you stop taking the drug.

Recommended Related to Hair Loss

Hair Problems

It can be long and wavy, short and straight, frizzy and unmanageable, or smooth and shiny. Hair comes in many different lengths, styles, colors, and textures. Yet just about everyone — no matter what kind of hair they have — falls prey to at least one hair problem at some point in life. This article covers some of the most common hair dilemmas, from hair loss to greasy hair.

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How Do Drugs Cause Hair Loss?

Drugs cause hair loss by interfering with the normal cycle of scalp hair growth. During the anagen phase, which lasts for three to four years, the hair grows. During the telogen phase, which lasts about three months, the hair rests. At the end of the telogen phase, the hair falls out and is replaced by a new hair.

Medications can lead to two types of hair loss: telogen effluvium and Anagen effluvium.

Telogen effluvium is the most common form of drug-induced hair loss. It usually appears within two to four months after taking the drug. This condition causes the hair follicles to go into their resting phase (telogen) and fall out too early. People with telogen effluvium usually shed between 100 and 150 hairs a day.

Anagen effluvium is hair loss that occurs during the anagen phase of the hair cycle, when the hairs are actively growing. It prevents the matrix cells, which produce new hairs, from dividing normally. This type of hair loss usually occurs within a few days to weeks after taking the medication. It’s most common in people who are taking chemotherapy drugs and is often severe, causing people to lose most or all of the hair on their head, as well as their eyebrows, eyelashes, and other body hairs.

The severity of drug-induced hair loss depends on the type of drug and dosage, as well as your sensitivity to that drug.

What Types of Drugs Cause Hair Loss?

Many different types of drugs are thought to cause hair loss, including:

  • Acne medications containing vitamin A (retinoids)
  • Antibiotics and antifungal drugs
  • Antidepressants
  • Birth control pills
  • Anticlotting drugs
  • Cholesterol-lowering drugs
  • Drugs that suppress the immune system
  • Drugs that treat breast cancer
  • Epilepsy drugs (anticonvulsants)
  • High blood pressure medications (anti-hypertensives), such as beta-blockers, ACE inhibitors, and diuretics
  • Hormone replacement therapy
  • Mood stabilizers
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Parkinson’s disease drugs
  • Steroids
  • Thyroid medications
  • Weight loss drugs

Chemotherapy drugs often lead to the anagen effluvium type of hair loss. As these drugs kill cancer cells throughout the body, they also can damage healthy cells, including hair matrix cells. The hair typically starts to fall out within two weeks of starting chemotherapy and progresses more rapidly after 1-2 months, according to the American Cancer Society. Hair loss is more common and severe in patients taking combinations of chemotherapy drugs than in those who take just one drug.

Chemotherapy drugs that tend to cause hair loss include:

  • adriamycin
  • cyclophosphamide
  • cactinomycin
  • docetaxel
  • doxorubicin
  • etoposide
  • ifosfamide
  • irinotecan
  • paclitaxel
  • topotecan
  • vinorelbine

 

How Is Drug-Induced Hair Loss Diagnosed?

If you are experiencing hair loss, your doctor will ask you several questions, including:

  • When did the hair loss start?
  • How quickly has the hair been falling out?
  • What other symptoms do you have, such as scalp itching, burning, or tingling?
  • What drugs were you taking in the four months leading up to the hair loss?
  • What other illnesses do you have?
  • Have you made any changes to your diet or hair-care routine?

The doctor also will examine your scalp to look at the pattern of hair loss.

Tests that may be done include:

  • Thyroid function tests to look for thyroid disorders, which can sometimes cause hair loss
  • Hair shaft exam to look at the shape, length, and fragility of the hairs
  • Pull test: gently pulling on about 60 hairs to see how many come out
  • Biopsy: removing a piece of scalp tissue for examination
  • Hormone tests

It can be difficult to prove which drug is causing the hair loss, or even that a drug is to blame. Your doctor may ask you to stop taking one drug at a time and see whether your hair stops falling out, but it can take two to three months after stopping a drug for the hair loss to end.

How Is Drug-Induced Hair Loss Treated?

It’s important to review any medications you take, and discuss their potential side effects with your doctor and pharmacist. When hair loss does occur from a drug you’re taking, there is a good chance that the hair will grow back on its own after you stop taking the medication. If stopping the drug does not improve hair thinning, you may need to be treated with finasteride (Propecia) or minoxidil (Rogaine), medications that slow hair loss and can stimulate new hair growth.

One technique may help prevent hair loss during chemotherapy. It’s called scalp hypothermia, and it involves placing ice packs on the scalp a few minutes before — and for about a half-hour after — chemotherapy treatment. Cooling the scalp reduces blood flow to the hair follicles, making it harder for the chemotherapy drugs to get into the follicular cells. Cooling also reduces biochemical activity, making the hair follicles less susceptible to damage from chemotherapy drugs.  One concern with this technique is the risk of cancer recurrence in the scalp.

After chemotherapy treatment, the hair usually grows back in very quickly, but it may change in texture. In rare cases, the hair will stay thin even after treatment has been stopped. Minoxidil can help regrow hair that is slow to return. Some chemotherapy patients wear a wig or hat to hide their hair loss until their hair grows back.

source: web MD

 

 

Enoxaparin and Antifactor Xa Levels in Acute Burn Patients

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Altered pharmacokinetics in critically ill patients have been shown to result in inadequate enoxaparin dosing for venous thromboembolism (VTE) prophylaxis. In the burn unit, routine monitoring of antifactor Xa levels was implemented to ensure adequate VTE prophylaxis. The purpose of this study was to examine the appropriateness of enoxaparin dosing for VTE prophylaxis in this specialized patient population. The authors reviewed patients with acute burn injury from June 1, 2009, to October 20, 2009, who had enoxaparin therapy monitored with antifactor Xa levels. Data collection occurred prospectively. Thirty-eight patients received enoxaparin subcutaneously for prophylaxis of VTE and had antifactor Xa levels measured. Thirty (79%) patients had initial antifactor Xa levels less than 0.2 U/ml. Enoxaparin dosages were subsequently increased as needed to achieve antifactor Xa levels of 0.2 to 0.4 U/ml. Eight of 38 patients never achieved goal antifactor Xa level before enoxaparin was discontinued. The median final dose required to achieve an antifactor Xa level within therapeutic range was 50 mg every 12 hours (range 30–70 mg). In linear regression, final enoxaparin dose correlated with TBSA. Two patients had clinically significant thromboembolic events. There were no documented episodes of significant hemorrhage, thrombocytopenia, or heparin-associated allergy. The low antifactor Xa levels observed in this study demonstrate that standard dosing of enoxaparin for VTE prophylaxis is inadequate for patients with acute burns. In these patients, both a higher initial enoxaparin dose and routine monitoring of antifactor Xa levels are recommended.

source: the journal of burn care and research