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Sunday, July 13, 2014

Gallstones

Many people can develop gallstones and never know it. Gallstones are hard deposits in your gallbladder, a small organ that stores bile, a digestive fluid made in the liver. Gallstones may consist of cholesterol, salt, or bilirubin, which are discarded red blood cells. Stones can range in size, from tiny sand grains to large ones the size of golf balls.
What Causes Gallstones?
Gallstones may develop when there is too much cholesterol in the bile secreted by your liver. Bile usually dissolves or breaks down cholesterol. But if your liver makes more cholesterol than your bile can dissolve, hard stones may develop.

Other causes include the following: 
Bilirubin
Bilirubin is a chemical produced when your liver destroys old red blood cells. Some conditions such as cirrhosis of the liver and certain blood disorders cause your liver to produce more bilirubin than it should. Stones form when your gallbladder cannot break down the excess bilirubin. These hard substances are also called pigmented stones.

Concentrated Bile

Your gallbladder needs to empty bile in order to be healthy and function properly. If it fails to empty its bile content, the bile becomes overly concentrated, which causes stones to form.

Who Is at Risk for Gallstones?

You may be at risk if you have one or more of the following risk factors:
  • over the age of 40
  • female
  • Native American or Hispanic descent
  • have or had an organ or bone marrow transplant
  • diabetes
  • cirrhosis of the liver
  • on a low-calorie diet that leads to rapid weight loss

What Are the Symptoms of Gallstones?

You may not experience any symptoms if you have gallstones. Your doctor may find stones in your gallbladder while doing X-rays or surgery in the abdomen. When symptoms are present, you may experience:
  • pain that radiates in your upper abdomen (normally on the right side or in the middle)
  • fever
  • a yellowish tint in your skin or eyes (jaundice)
  • nausea or vomiting
  • clay-colored stools

How Are Gallstones Diagnosed?

Your doctor will perform a physical examination that includes checking your eyes and skin for visible changes in color. A yellowish tint in your skin or eyes may be signs of jaundice. Too much bilirubin in your body causes jaundice.
The examination may involve using diagnostic testing to see inside your body. These tests include:
Abdominal CT Scan
This is an imaging test that takes pictures of your liver and abdominal region.
Ultrasound
Ultrasound tests produce images of your abdomen.
Gallbladder Radionuclide Scan
This very important scan takes about one hour to complete. A specialist injects a radioactive substance into your veins. The substance travels through your blood to the liver and gallbladder. It highlights any infection or blockages in these organs.
Blood Tests
Your doctor may order blood tests that measure the amount of bilirubin in your blood. The tests also gauge how well your liver is functioning.

How Are Gallstones Treated?

Your doctor may use any of several treatment options to remove stones or improve your condition.
Surgeries
Surgery is often the first option if you have symptoms. A surgeon may perform a commonly used technique called laparoscopic gallbladder removal.
General anesthesia is required. Three to four incisions are made on your abdomen. The surgeon inserts a small, lighted device into one of the incisions and carefully removes your gallbladder. You usually go home on the day of the procedure if you have no complications.

Medications

Drugs that dissolve gallstones caused by cholesterol are an option if you cannot undergo surgery. These medications may take several years to eliminate the gallstones.

What Can I Expect in the Long Term?

Surgery to remove your gallbladder or any stones in your gallbladder is often successful. In most cases, stones do not return.

Can I Prevent Gallstones?

You can’t prevent gallstones, but you can reduce your risk with lifestyle strategies. Eat a balanced diet. Do not skip meals. Drink sufficient amounts of water each day to keep your body hydrated.
If you plan to lose weight, do it slowly. Aim to lose no more than two pounds a week. Quick weight loss may increase your risk for gallstones and other health problems.

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Saturday, July 12, 2014

Kidney Stones

What is a kidney stone?

A kidney stone is a solid piece of material that forms in a kidney when substances that are normally found in the urine become highly concentrated. A stone may stay in the kidney or travel down the urinary tract. Kidney stones vary in size. A small stone may pass on its own, causing little or no pain. A larger stone may get stuck along the urinary tract and can block the flow of urine, causing severe pain or bleeding.

Kidney stones are one of the most common disorders of the urinary tract. Each year in the United States, people make more than a million visits to health care providers and more than 300,000 people go to emergency rooms for kidney stone problems.

Urolithiasis is the medical term used to describe stones occurring in the urinary tract. Other frequently used terms are urinary tract stone disease and nephrolithiasis. Terms that describe the location of the stone in the urinary tract are sometimes used. For example, a ureteral stone—or ureterolithiasis—is a kidney stone found in the ureter.

What is the urinary tract?

The urinary tract is the body’s drainage system for removing wastes and extra water. The urinary tract includes two kidneys, two ureters, a bladder, and a urethra. The kidneys are two bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage, one on each side of the spine. Every day, the two kidneys process about 200 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra water. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination. When the bladder empties, urine flows out of the body through a tube called the urethra at the bottom of the bladder.


Kidney stones in the kidney and urinary tract

Who gets kidney stones?

Anyone can get a kidney stone, but some people are more likely to get one. Men are affected more often than women, and kidney stones are more common in non-Hispanic white people than in non-Hispanic black people and Mexican Americans. Overweight and obese people are more likely to get a kidney stone than people of normal weight. In the United States, 8.8 percent of the population, or one in 11 people, have had a kidney stone.

What causes kidney stones?


Kidney stones can form when substances in the urine—such as calcium, oxalate, and phosphorus—become highly concentrated. Certain foods may promote stone formation in people who are susceptible, but scientists do not believe that eating any specific food causes stones to form in people who are not susceptible. People who do not drink enough fluids may also be at higher risk, as their urine is more concentrated.

  • People who are at increased risk of kidney stones are those with
  • hypercalciuria, a condition that runs in families in which urine contains unusually large amounts of calcium; this is the most common condition found in those who form calcium stones
  • a family history of kidney stones
  • cystic kidney diseases, which are disorders that cause fluid-filled sacs to form on the kidneys
  • hyperparathyroidism, a condition in which the parathyroid glands, which are four pea-sized glands located in the neck, release too much hormone, causing extra calcium in the blood
  • renal tubular acidosis, a disease that occurs when the kidneys fail to excrete acids into the urine, which causes a person’s blood to remain too acidic
  • cystinuria, a condition in which urine contains high levels of the amino acid cystine
  • hyperoxaluria, a condition in which urine contains unusually large amounts of oxalate
  • hyperuricosuria, a disorder of uric acid metabolism
  • gout, a disorder that causes painful swelling of the joints
  • blockage of the urinary tract
  • chronic inflammation of the bowel
  • a history of gastrointestinal (GI) tract surgery
  • Others at increased risk of kidney stones are people taking certain medications including
  • diuretics—medications that help the kidneys remove fluid from the body
  • calcium-based antacids
  • the protease inhibitor indinavir (Crixivan), a medication used to treat HIV infection
  • the anti-seizure medication topiramate (Topamax)

What are the types of kidney stones?

Four major types of kidney stones can form:
  • Calcium stones are the most common type of kidney stone and occur in two major forms: calcium oxalate and calcium phosphate. Calcium oxalate stones are more common. Calcium oxalate stone formation may be caused by high calcium and high oxalate excretion. Calcium phosphate stones are caused by the combination of high urine calcium and alkaline urine, meaning the urine has a high pH.
  • Uric acid stones form when the urine is persistently acidic. A diet rich in purines—substances found in animal protein such as meats, fish, and shellfish—may increase uric acid in urine. If uric acid becomes concentrated in the urine, it can settle and form a stone by itself or along with calcium.
  • Struvite stones result from kidney infections. Eliminating infected stones from the urinary tract and staying infection-free can prevent more struvite stones.
  • Cystine stones result from a genetic disorder that causes cystine to leak through the kidneys and into the urine, forming crystals that tend to accumulate into stones.

What do kidney stones look like?



Kidney stones vary in size and shape. Stones may be as small as a grain of sand or as large as a pearl. Some stones are even as big as golf balls. Stones may be smooth or jagged and are usually yellow or brown.


Kidney stones vary in size and shape. These stones are not actual size.

What are the symptoms of kidney stones?


People with kidney stones may have pain while urinating, see blood in the urine, or feel a sharp pain in the back or lower abdomen. The pain may last for a short or long time. People may experience nausea and vomiting with the pain. However, people who have small stones that pass easily through the urinary tract may not have symptoms at all.

How are kidney stones diagnosed?


To diagnose kidney stones, the health care provider will perform a physical exam and take a medical history. The medical history may include questions about family history of kidney stones, diet, GI problems, and other diseases and disorders. The health care provider may perform urine, blood, and imaging tests, such as an x ray or computerized tomography (CT) scan to complete the diagnosis.
  • Urinalysis. Urinalysis is testing of a urine sample. The urine sample is collected in a special container in a health care provider’s office or commercial facility and can be tested in the same location or sent to a lab for analysis. Urinalysis can show whether the person has an infection or the urine contains substances that form stones.
  • Blood test. A blood test involves drawing blood at a health care provider’s office or commercial facility and sending the sample to a lab for analysis. The blood test can show biochemical problems that can lead to kidney stones.
  • Abdominal x ray. An abdominal x ray is a picture created using radiation and recorded on film or on a computer. The amount of radiation used is small. An x ray is performed at a hospital or outpatient center by an x-ray technician, and the images are interpreted by a radiologist—a doctor who specializes in medical imaging. Anesthesia is not needed. The person will lie on a table or stand during the x ray. The x-ray machine is positioned over the abdominal area. The person will hold his or her breath as the picture is taken so that the picture will not be blurry. The person may be asked to change position for additional pictures. The x rays can show the location of stones in the kidney or urinary tract.
  • CT scans. CT scans use a combination of x rays and computer technology to create three-dimensional (3-D) images. A CT scan may include the injection of a special dye, called contrast medium. CT scans require the person to lie on a table that slides into a tunnel-shaped device where the x rays are taken. The procedure is performed in an outpatient center or hospital by an x-ray technician, and the images are interpreted by a radiologist. Anesthesia is not needed. CT scans can show stone locations and conditions that may have caused the stone to form.

How are kidney stones treated?

Treatment for kidney stones usually depends on their size and what they are made of, as well as whether they are causing pain or obstructing the urinary tract. Kidney stones may be treated by a general practitioner or by a urologist—a doctor who specializes in the urinary tract. Small stones usually pass through the urinary tract without treatment. Still, the person may need pain medication and should drink lots of fluids to help move the stone along. Pain control may consist of oral or intravenous (IV) medication, depending on the duration and severity of the pain. IV fluids may be needed if the person becomes dehydrated from vomiting or an inability to drink. A person with a larger stone, or one that blocks urine flow and causes great pain, may need more urgent treatment, such as
  • Shock wave lithotripsy. A machine called a lithotripter is used to crush the kidney stone. The procedure is performed by a urologist on an outpatient basis and anesthesia is used. In shock wave lithotripsy, the person lies on a table or, less commonly, in a tub of water above the lithotripter. The lithotripter generates shock waves that pass through the person’s body to break the kidney stone into smaller pieces to pass more readily through the urinary tract.
  • Ureteroscopy. A ureteroscope—a long, tubelike instrument with an eyepiece—is used to find and retrieve the stone with a small basket or to break the stone up with laser energy. The procedure is performed by a urologist in a hospital with anesthesia. The urologist inserts the ureteroscope into the person’s urethra and slides the scope through the bladder and into the ureter. The urologist removes the stone or, if the stone is large, uses a flexible fiber attached to a laser generator to break the stone into smaller pieces that can pass out of the body in the urine. The person usually goes home the same day.

Ureteroscopic stone removal
  • Percutaneous nephrolithotomy. In this procedure, a wire-thin viewing instrument called a nephroscope is used to locate and remove the stone. The procedure is performed by a urologist in a hospital with anesthesia. During the procedure, a tube is inserted directly into the kidney through a small incision in the person’s back. For large stones, an ultrasonic probe that acts as a lithotripter may be needed to deliver shock waves that break the stone into small pieces that can be removed more easily. The person may have to stay in the hospital for several days after the procedure and may have a small tube called a nephrostomy tube inserted through the skin into the kidney. The nephrostomy tube drains urine and any residual stone fragments from the kidney into a urine collection bag. The tube is usually left in the kidney for 2 or 3 days while the person remains in the hospital.
Drawing of a kidney cross section with a kidney stone. A wire called a nephroscope is inserted through the skin into the kidney to locate the stone. A thicker probe labeled ultrasonic probe is inserted through the skin into the kidney to deliver sound waves that will break up the kidney stone.
Percutaneous nephrolithotomy

Nephrostomy tube

How are kidney stones prevented?


The first step in preventing kidney stones is to understand what is causing the stones to form. The health care provider may ask the person to try to catch the kidney stone as it passes, so it can be sent to a lab for analysis. Stones that are retrieved surgically can also be sent to a lab for analysis.

The health care provider may ask the person to collect urine for 24 hours after a stone has passed or been removed to measure daily urine volume and mineral levels. Producing too little urine or having a mineral abnormality can make a person more likely to form stones. Kidney stones may be prevented through changes in eating, diet, and nutrition and medications.

Eating, Diet, and Nutrition


People can help prevent kidney stones by making changes in their fluid intake. Depending on the type of kidney stone a person has, changes in the amounts of sodium, animal protein, calcium, and oxalate consumed can also help.
Drinking enough fluids each day is the best way to help prevent most types of kidney stones. Health care providers recommend that a person drink 2 to 3 liters of fluid a day. People with cystine stones may need to drink even more. Though water is best, other fluids may also help prevent kidney stones, such as citrus drinks.
Recommendations based on the specific type of kidney stone include the following:
Calcium Oxalate Stones
  • reducing sodium
  • reducing animal protein, such as meat, eggs, and fish
  • getting enough calcium from food or taking calcium supplements with food
  • avoiding foods high in oxalate, such as spinach, rhubarb, nuts, and wheat bran 
Calcium Phosphate Stones
  • reducing sodium
  • reducing animal protein
  • getting enough calcium from food or taking calcium supplements with food
    • Uric Acid Stones
  • limiting animal protein
More information about how changes in diet affect kidney stone formation can be found in the National Kidney and Urologic Diseases Information Clearinghouse fact sheet Diet for Kidney Stone Prevention at www.kidney.niddk.nih.gov.
Medications
  • The health care provider may prescribe certain medications to help prevent kidney stones based on the type of stone formed or conditions that make a person more prone to form stones:
  • hyperuricosuria—allopurinol (Zyloprim), which decreases uric acid in the blood and urine
  • hypercalciuria—diuretics, such as hydrochlorothiazide
  • hyperoxaluria—potassium citrate to raise the citrate and pH of urine
  • uric acid stones—allopurinol and potassium citrate
  • cystine stones—mercaptopropionyl glycine, which decreases cystine in the urine, and potassium citrate
  • struvite stones—antibiotics, which are bacteria-fighting medications, when needed to treat infections, or acetohydroxamic acid with long-term antibiotic medications to prevent infection
People with hyperparathyroidism sometimes develop calcium stones. Treatment in these cases is usually surgery to remove the parathyroid glands. In most cases, only one of the glands is enlarged. Removing the glands cures hyperparathyroidism and prevents kidney stones.

Points to Remember


  • A kidney stone is a solid piece of material that forms in a kidney when substances that are normally found in the urine become highly concentrated.
  • Kidney stones are one of the most common disorders of the urinary tract.
  • Certain foods may promote stone formation in people who are susceptible, but scientists do not believe that eating any specific food causes stones to form in people who are not susceptible.
  • People with kidney stones may have pain while urinating, see blood in the urine, or feel a sharp pain in the back or lower abdomen. However, people who have small stones that pass easily through the urinary tract may not have symptoms at all.
  • To diagnose kidney stones, the health care provider will perform a physical exam and take a medical history. The health care provider may perform urine, blood, and imaging tests to complete the diagnosis.
  • Treatment for kidney stones usually depends on their size and what they are made of, as well as whether they are causing pain or obstructing the urinary tract. Treatments may include shock wave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy.
  • Kidney stones may be prevented through changes in eating, diet, and nutrition and medications.

Hope through Research


The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) funds research on the causes, treatments, and prevention of kidney stones. The International Registry for Hereditary Kidney Stone Diseases, funded under National Institutes of Health (NIH) clinical trial number NCT00588562, collects medical information from a large number of patients with kidney stones to create a registry that will help researchers compare similarities and differences in patients and their symptoms.

The Study of the Biological and Physical Manifestations of Spontaneous Uric Acid Kidney Stone Disease, funded under NIH clinical trial number NCT00904046, aims to determine how much fat accumulates within cells and how it affects the kidneys by correlating kidney fat content with urine test results. A second aim is to evaluate the effect of the medication thiazolidinedione on excess fatty acid accumulation in kidney tissue and its correlation with uric acid stone formation.

Tamsulosin for Urolithiasis in the Emergency Department, funded under NIH clinical trial number NCT00382265, studies the effectiveness and safety of tamsulosin in treatment of kidney stones. Other areas of focus include reduction in time to pain-free recovery, decrease in narcotic medication for pain, less need for follow-up, decrease in the need for surgery, and cost savings.

Clinical trials are research studies involving people. Clinical trials look at safe and effective new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. To learn more about clinical trials, why they matter, and how to participate, visit the NIH Clinical Research Trials and You website at www.nih.gov/health/clinicaltrials. For information about current studies, visit www.ClinicalTrials.gov.
Source: kidney.niddk.nih.gov/kudiseases/pubs/stonesadults/
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Thursday, July 10, 2014

Google Glass hack allows brainwave control

Dave Lee tested the software hack at This Place's London office

Google Glass has been hacked so that it can be controlled by brainwaves.

By combining the smart glasses with an electroencephalography (EEG) headset, the software makes it possible to take a picture without moving a muscle.
London-based start-up This Place said the tech could be utilised in high-pressure hands-free situations - such as during surgery.
It has released the MindRDR software for free in the hope that developers will adapt it for other uses.
Google made it clear that it does not support the app.
"Google Glass cannot read your mind," a spokeswoman told the BBC.
"This particular application seems to work through a separate piece of kit which you attach to Glass.
The app needs to be paired with an EEG
 headset to be able to control Google Glass

"We have not reviewed, nor approved, the app so it won't be available in the Glass app store."

Google launched Glass in the UK last month.
The spokeswoman added: "Of course, we are always interested in hearing about new applications of Glass and we've already seen some great research from a variety of medical fields from surgery to Parkinson's."

Concentration camera

An EEG headset can be used to measure when certain parts of the brain show a greater level of activity.
In this case, the MindRDR software monitors when the wearer engages in high levels of concentration.
Within Google Glass's "screen" - a small window that appears in the corner of the wearer's right eye - 
a white horizontal line is shown.
As a user concentrates, the white line rises up the screen. Once it reaches the top, a picture is taken using Glass's inbuilt camera.
The software allows the wearer to take a photo
 and post it online just by thinking

Repeating this process


Google Glass users run the risk of attracting even more stares by wearing the extra kit

 will then post it to a pre-configured social media profile.
At present, Google Glass is controlled by either voice command - "OK Glass, take a picture" - or by tapping and swiping on the side of the device.
"We wanted to realise the true potential of Glass by allowing users to control it with their minds," said Dusan Hamlin, chief executive of This Place.
"Currently, users either have to touch it or use voice commands, which are restrictive for some social situations and for users with disabilities."
'Wider world'
The firm's creative director Chloe Kirton said: "While MindRDR's current capabilities are limited to taking and sharing an image, the possibilities of Google Glass 'telekinesis' are vast.
"In the future, MindRDR could give those with conditions like locked-in syndrome, severe multiple sclerosis or quadriplegia the opportunity to interact with the wider world through wearable technology."

EEG technology is a growing area.

In the past, the equipment was prohibitively expensive, but many headsets are now available for less than £100.

Mick Donegan is the founder of SpecialEffect, a charity which adapts games controllers so they can be used by people with limited mobility.

He told the BBC that there had been some issues with the reliability of EEG headsets in the past, but that he was excited by the possibilities of the Google Glass hack.

"It will mean someone who currently has no control at all, who can't even control the movement of their eyes - those people will be able to use that system. For me, that's the final frontier," he said,

He added that developers would have to make intuitive user interfaces.

"Instead of people controlling a cursor, if you have a carefully designed interface that goes through options on a screen to choose - that's taking the load of the user. That's what you're looking for."

Other applications have included video games that attempt to monitor your emotional state, and change the game experience accordingly.

However, the technology is in its infancy - early experimental games have suffered from a lack of precision, leading to frustration among players.

Source:  Dave Lee  news from BBC
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Sunday, July 6, 2014

Gate Control Theory and Pain Management


Pain perception varies across different individuals according to their mood, emotional condition and prior experience, even if the pain is caused by similar physical stimuli and results in a similar degree of damage. In 1965, Ronald Melzack and Patrick Wall outlined a scientific theory about psychological influence on pain perception; the ‘gate control theory’.
If not for this theory, pain perception would be still associated with the intensity of the pain stimulus and the degree of damage caused to the affected tissue. But Melzack and Wall made it evident that pain perception is far more complex.
According to the gate control theory, pain signals are not free to reach the brainas soon as they are generated at the injured tissues or sites. They need to encounter certain ‘neurological gates’ at the spinal cord level and these gates determine whether the pain signals should reach the brain or not. In other words, pain is perceived when the gate gives way to the pain signals and it is less intense or not at all perceived when the gate closes for the signals to pass through. This theory gives the explanation for why someone finds relief byrubbing or massaging an injured or a painful area.
Though the gate control theory cannot present the complete picture of the central system that underlies pain, it has visualized the mechanism of pain perception in a new dimension and it has paved the way for various pain management strategies.
Peripheral nerve fibers involved in transmission of sensory signals
Every organ or part of the human body has its own nerve supply and the nerves carry the electrical impulses generated in response to various sensations like touch, temperature, pressure and pain. These nerves – that constitute the peripheral nervous system – transmit these impulses to the central nervous system (the brain and spinal cord) so that these impulses are interpreted and perceived as sensations. The peripheral nerves send signals to the dorsal horn of the spinal cord and from there the sensory signals are transmitted to the brain through the spinothalamic tract. Pain is a sensation that alerts a person that a tissue or a particular part of the human body has been injured or damaged.
According to the axonal diameter and the conduction velocity, nerve fibers can be classified into three types – A, B and C. The C fibers are the smallest among all the three types. Among the ‘A’ fibers are four subtypes: A-alpha, A-beta, A-gamma and A-delta. Among the A subtypes, the A-alpha fibers are the largest and the A-delta fibers are the smallest.
The A fibers that are larger than the A-delta fibers, carry sensations like touch, pressure, etc. to the spinal cord. The A-delta fibers and the C fibers carry pain signals to the spinal cord. A-delta fibers are faster and carry sharp pain signals while the C fibers are slower and carry diffuse pain signals.
When considering the conduction velocity, the A-alpha fibers (the large nerve fibers) have higher conduction velocity when compared to the A-delta fibers and the C fibers (small nerve fibers). When a tissue is injured, the A-delta fibers are activated first, followed by the activation of the C fibers. These fibers tend to carry the pain signals to the spinal cord and then to the brain. But the pain signals are not transmitted simply like that.
What does the gate control theory say?
The gate control theory suggests that the signals encounter ‘nerve gates’ at the level of the spinal cord and they need to get cleared through these gates to reach the brain. Various factors determine how the pain signals should be treated at the neurological gates. They are:
The intensity of the pain signals
The intensity of the other sensory signals (touch, temperature and pressure), if generated at the site of injury
The message from the brain itself (to send the pain signals or not)

As already mentioned, the nerve fibers, large and small, carrying the sensory signals, end in the dorsal horn of the spinal cord from where the signals are transmitted to the brain. According to the original postulate of Melzack and Wall, the nerve fibers project to the substantia gelatinosa (SG) of the dorsal horn and the first central transmission (T) cells of the spinal cord. The SG consists of inhibitory interneurons that act as the gate and determine which signals should reach the T cells and then go further through the spinothalamic tract to reach the brain.

When the pain signals carried by the small fibers (A-delta and C fibers) are less intense compared to the other non-pain sensory signals like touch, pressure and temperature, the inhibitory neurons prevent the transmission of the pain signals through the T cells. The non-pain signals override the pain signals and thus the pain is not perceived by the brain. When the pain signals are more intense compared to the non-pain signals, the inhibitory neurons are inactivated and the gate is opened. The T cells transmit the pain signals to the spinothalamic tract that carries those signals to the brain. As a result, the neurological gate is influenced by the relative amount of activity in the large and the small nerve fibers.

Emotions and thoughts determine the way how pain is perceived

The theory also proposed that the pain signal transmission can be influenced by emotions and thoughts. It is well known that people do not feel a chronic pain or, to be more appropriate, the pain does not disturb them when they concentrate on other activities that interest them. Whereas, people who are anxious or depressed feel intense pain and find it difficult to cope up with it. This is because the brain sends messages through descending fibers that stop, reduce or amplify the transmission of pain signals through the gate, depending on the thoughts and emotions of a person.

Gate control theory in pain management

The gate control theory has brought about a drastic revolution in the field of pain management. The theory suggested that pain management can be achieved by selectively influencing the larger nerve fibers that carry non-pain stimuli. The theory has also paved way for more research on cognitive and behavioral approaches to achieve pain relief.

One of the tremendous advances in pain management research is the advent of Transcutaneous Electrical Nerve Stimulation (TENS). The gate control theory forms the basis of TENS. In this technique, the selective stimulation of the large diameter nerve fibers carrying non-pain sensory stimuli from a specific region nullifies or reduces the effect of pain signals from the region. TENS is a non-invasive and inexpensive pain management approach that has been widely used for the treatment of chronic and intractable pain that are otherwise non-responsive to analgesics and surgical treatments. TENS is highly advantageous over pain medications in the aspect that it does not have the problem of drug interactions and toxicity.

Many other invasive and non-invasive electrical stimulation techniques have been found to be useful in various chronic pain conditions like arthritic pain, diabetic neuropathy, fibromyalgia, etc. The theory has also been extensively studied in the treatment of chronic back pain and cancer pain. However, favorable results are not attained in some conditions and the long term efficacy of the techniques based on the theory is under question.

Nevertheless, the gate control theory has dramatically revolutionized the field of pain research and it has sown seeds for numerous studies that aim at presenting a pain-free lifestyle to the patients who suffer from chronic pain.
Source : brainblogger
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Friday, July 4, 2014

Samsung has announced it will scrap plasma TVs

Samsung is to stop producing plasma televisions (PDP TVs) by 30 November.
It said falling demand meant it would instead focus on producing curved and ultra-high-definition (UHD) TVs.
"We remain committed to providing consumers with products that meet their need," Samsung told the CNET website.
Panasonic, Sony, Hitachi and Pioneer have also pulled out of the sector in recent years. And, according to the Tech Radar website, LG is expected to follow suit soon.
Plasma screens, which use electrically charged ionised gases, are often applauded for their brightness, deep blacks, and high frame rates, considered ideal for watching sport and films.
But they tend to use more electricity and are considerably bulkier than the now more popular liquid-crystal display (LCD) and light-emitting diode (LED) TVs.

Stylish tellies

TrustedReviews website editor Evan Kypreos said: "It's not at all surprising that Samsung has dumped plasma.
"The main issue is that it's very tricky to make [UHD] plasmas, and [UHD] is the future of big TVs.
"While plasma is a lot better than LED/LCD TVs in terms of image quality, such as contrast ratio, and motion handling, it has a few drawbacks.
"Plasma TVs can't be made a thin as LEDs, for example. People like stylish tellies."
With the introduction of increasingly advanced organic LED TVs, which arguably have better black levels, brightness and colour gamut than plasmas, there was little reason to continue manufacturing plasma screens, Mr Kypreos said.
"Home-cinema connoisseurs will always have a soft spot for plasmas, but they have simply been technologically superseded," he said.
Source BBC
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Thursday, July 3, 2014

How to make Rainbow

Hello friends are you want to learn how to make a rainbow with this fun science experiment for kids and all. Using just a few simple everyday items you can find out how rainbows work while enjoying an interactive, hands on activity that’s perfect for alls.

What you'll need:

A glass of water (about three quarters full)
White paper
A sunny day

Instructions:

Take the glass of water and paper to a part of the room with sunlight (near a window is good).
Hold the glass of water (being careful not to spill it) above the paper and watch as sunlight passes through the glass of water, refracts (bends) and forms a rainbow of colors on your sheet of paper.
Try holding the glass of water at different heights and angles to see if it has a different effect.

What's happening?

While you normally see a rainbow as an arc of color in the sky, they can also form in other situations. You may have seen a rainbow in a water fountain or in the mist of a waterfall and you can even make your own such as you did in this experiment.

Rainbows form in the sky when sunlight refracts (bends) as it passes through raindrops, it acts in the same way when it passes through your glass of water. The sunlight refracts, separating it into the colors red, orange, yellow, green, blue, indigo and violet.
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